From dd21c8a577f8bfba9caa58c7567893b2ec10aef9 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Wed, 10 Aug 2016 17:27:46 -0700
Subject: Rev nlohmann/json

---
 ext/json/json.hpp | 2306 +++++++++++++++++++++++++++++------------------------
 1 file changed, 1279 insertions(+), 1027 deletions(-)

(limited to 'ext/json/json.hpp')

diff --git a/ext/json/json.hpp b/ext/json/json.hpp
index 9d6687dd..878fb899 100644
--- a/ext/json/json.hpp
+++ b/ext/json/json.hpp
@@ -1,7 +1,7 @@
 /*
     __ _____ _____ _____
  __|  |   __|     |   | |  JSON for Modern C++
-|  |  |__   |  |  | | | |  version 2.0.0
+|  |  |__   |  |  | | | |  version 2.0.2
 |_____|_____|_____|_|___|  https://github.com/nlohmann/json
 
 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
@@ -32,11 +32,10 @@ SOFTWARE.
 #include <algorithm>
 #include <array>
 #include <cassert>
-#include <cerrno>
 #include <ciso646>
 #include <cmath>
 #include <cstddef>
-#include <cstdio>
+#include <cstdint>
 #include <cstdlib>
 #include <functional>
 #include <initializer_list>
@@ -44,8 +43,10 @@ SOFTWARE.
 #include <iostream>
 #include <iterator>
 #include <limits>
+#include <locale>
 #include <map>
 #include <memory>
+#include <numeric>
 #include <sstream>
 #include <stdexcept>
 #include <string>
@@ -53,6 +54,19 @@ SOFTWARE.
 #include <utility>
 #include <vector>
 
+// exclude unsupported compilers
+#if defined(__clang__)
+    #define CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
+    #if CLANG_VERSION < 30400
+        #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
+    #endif
+#elif defined(__GNUC__)
+    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
+    #if GCC_VERSION < 40900
+        #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
+    #endif
+#endif
+
 // disable float-equal warnings on GCC/clang
 #if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
     #pragma GCC diagnostic push
@@ -76,7 +90,13 @@ namespace
 {
 /*!
 @brief Helper to determine whether there's a key_type for T.
+
+Thus helper is used to tell associative containers apart from other containers
+such as sequence containers. For instance, `std::map` passes the test as it
+contains a `mapped_type`, whereas `std::vector` fails the test.
+
 @sa http://stackoverflow.com/a/7728728/266378
+@since version 1.0.0
 */
 template<typename T>
 struct has_mapped_type
@@ -90,11 +110,18 @@ struct has_mapped_type
 
 /*!
 @brief helper class to create locales with decimal point
+
+This struct is used a default locale during the JSON serialization. JSON
+requires the decimal point to be `.`, so this function overloads the
+`do_decimal_point()` function to return `.`. This function is called by
+float-to-string conversions to retrieve the decimal separator between integer
+and fractional parts.
+
 @sa https://github.com/nlohmann/json/issues/51#issuecomment-86869315
+@since version 2.0.0
 */
-class DecimalSeparator : public std::numpunct<char>
+struct DecimalSeparator : std::numpunct<char>
 {
-  protected:
     char do_decimal_point() const
     {
         return '.';
@@ -163,6 +190,13 @@ default)
    JSON values can be used like STL containers and provide reverse iterator
    access.
 
+@invariant The member variables @a m_value and @a m_type have the following
+relationship:
+- If `m_type == value_t::object`, then `m_value.object != nullptr`.
+- If `m_type == value_t::array`, then `m_value.array != nullptr`.
+- If `m_type == value_t::string`, then `m_value.string != nullptr`.
+The invariants are checked by member function assert_invariant().
+
 @internal
 @note ObjectType trick from http://stackoverflow.com/a/9860911
 @endinternal
@@ -188,13 +222,8 @@ class basic_json
 {
   private:
     /// workaround type for MSVC
-    using basic_json_t = basic_json<ObjectType,
-          ArrayType,
-          StringType,
-          BooleanType,
-          NumberIntegerType,
-          NumberUnsignedType,
-          NumberFloatType,
+    using basic_json_t = basic_json<ObjectType, ArrayType, StringType,
+          BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType,
           AllocatorType>;
 
   public:
@@ -207,6 +236,8 @@ class basic_json
     /////////////////////
 
     /// @name container types
+    /// The canonic container types to use @ref basic_json like any other STL
+    /// container.
     /// @{
 
     /// the type of elements in a basic_json container
@@ -256,6 +287,8 @@ class basic_json
     ///////////////////////////
 
     /// @name JSON value data types
+    /// The data types to store a JSON value. These types are derived from
+    /// the template arguments passed to class @ref basic_json.
     /// @{
 
     /*!
@@ -358,7 +391,7 @@ class basic_json
 
     @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
     `std::list`)
-    @tparam AllocatorType  allocator to use for arrays (e.g., `std::allocator`)
+    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
 
     #### Default type
 
@@ -595,15 +628,14 @@ class basic_json
     > that implementations will agree exactly on their numeric values.
 
     As this range is a subrange (when considered in conjunction with the
-    number_integer_t type) of the exactly supported range [0, UINT64_MAX], this
-    class's integer type is interoperable.
+    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
+    this class's integer type is interoperable.
 
     #### Storage
 
     Integer number values are stored directly inside a @ref basic_json type.
 
     @sa @ref number_float_t -- type for number values (floating-point)
-
     @sa @ref number_integer_t -- type for number values (integer)
 
     @since version 2.0.0
@@ -691,7 +723,19 @@ class basic_json
     This enumeration collects the different JSON types. It is internally used
     to distinguish the stored values, and the functions @ref is_null(), @ref
     is_object(), @ref is_array(), @ref is_string(), @ref is_boolean(), @ref
-    is_number(), and @ref is_discarded() rely on it.
+    is_number() (with @ref is_number_integer(), @ref is_number_unsigned(), and
+    @ref is_number_float()), @ref is_discarded(), @ref is_primitive(), and
+    @ref is_structured() rely on it.
+
+    @note There are three enumeration entries (number_integer,
+    number_unsigned, and number_float), because the library distinguishes
+    these three types for numbers: @ref number_unsigned_t is used for unsigned
+    integers, @ref number_integer_t is used for signed integers, and @ref
+    number_float_t is used for floating-point numbers or to approximate
+    integers which do not fit in the limits of their respective type.
+
+    @sa @ref basic_json(const value_t value_type) -- create a JSON value with
+    the default value for a given type
 
     @since version 1.0.0
     */
@@ -702,7 +746,7 @@ class basic_json
         array,           ///< array (ordered collection of values)
         string,          ///< string value
         boolean,         ///< boolean value
-        number_integer,  ///< number value (integer)
+        number_integer,  ///< number value (signed integer)
         number_unsigned, ///< number value (unsigned integer)
         number_float,    ///< number value (floating-point)
         discarded        ///< discarded by the the parser callback function
@@ -711,73 +755,6 @@ class basic_json
 
   private:
 
-    /*!
-    @brief a type to hold JSON type information
-
-    This bitfield type holds information about JSON types. It is internally
-    used to hold the basic JSON type enumeration, as well as additional
-    information in the case of values that have been parsed from a string
-    including whether of not it was created directly or parsed, and in the
-    case of floating point numbers the number of significant figures in the
-    original representaiton and if it was in exponential form, if a '+' was
-    included in the exponent and the capitilization of the exponent marker.
-    The sole purpose of this information is to permit accurate round trips.
-
-    @since version 2.0.0
-    */
-    union type_data_t
-    {
-        struct
-        {
-            /// the type of the value (@ref value_t)
-            uint16_t type : 4;
-            /// whether the number was parsed from a string
-            uint16_t parsed : 1;
-            /// whether parsed number contained an exponent ('e'/'E')
-            uint16_t has_exp : 1;
-            /// whether parsed number contained a plus in the exponent
-            uint16_t exp_plus : 1;
-            /// whether parsed number's exponent was capitalized ('E')
-            uint16_t exp_cap : 1;
-            /// the number of figures for a parsed number
-            uint16_t precision : 8;
-        } bits;
-        uint16_t data;
-
-        /// return the type as value_t
-        operator value_t() const
-        {
-            return static_cast<value_t>(bits.type);
-        }
-
-        /// test type for equality (ignore other fields)
-        bool operator==(const value_t& rhs) const
-        {
-            return static_cast<value_t>(bits.type) == rhs;
-        }
-
-        /// assignment
-        type_data_t& operator=(value_t rhs)
-        {
-            bits.type = static_cast<uint16_t>(rhs) & 15; // avoid overflow
-            return *this;
-        }
-
-        /// construct from value_t
-        type_data_t(value_t t) noexcept
-        {
-            *reinterpret_cast<uint16_t*>(this) = 0;
-            bits.type = static_cast<uint16_t>(t) & 15; // avoid overflow
-        }
-
-        /// default constructor
-        type_data_t() noexcept
-        {
-            data = 0;
-            bits.type = reinterpret_cast<uint16_t>(value_t::null);
-        }
-    };
-
     /// helper for exception-safe object creation
     template<typename T, typename... Args>
     static T* create(Args&& ... args)
@@ -789,6 +766,7 @@ class basic_json
         };
         std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
         alloc.construct(object.get(), std::forward<Args>(args)...);
+        assert(object.get() != nullptr);
         return object.release();
     }
 
@@ -799,7 +777,24 @@ class basic_json
     /*!
     @brief a JSON value
 
-    The actual storage for a JSON value of the @ref basic_json class.
+    The actual storage for a JSON value of the @ref basic_json class. This
+    union combines the different storage types for the JSON value types
+    defined in @ref value_t.
+
+    JSON type | value_t type    | used type
+    --------- | --------------- | ------------------------
+    object    | object          | pointer to @ref object_t
+    array     | array           | pointer to @ref array_t
+    string    | string          | pointer to @ref string_t
+    boolean   | boolean         | @ref boolean_t
+    number    | number_integer  | @ref number_integer_t
+    number    | number_unsigned | @ref number_unsigned_t
+    number    | number_float    | @ref number_float_t
+    null      | null            | *no value is stored*
+
+    @note Variable-length types (objects, arrays, and strings) are stored as
+    pointers. The size of the union should not exceed 64 bits if the default
+    value types are used.
 
     @since version 1.0.0
     */
@@ -903,6 +898,21 @@ class basic_json
         }
     };
 
+    /*!
+    @brief checks the class invariants
+
+    This function asserts the class invariants. It needs to be called at the
+    end of every constructor to make sure that created objects respect the
+    invariant. Furthermore, it has to be called each time the type of a JSON
+    value is changed, because the invariant expresses a relationship between
+    @a m_type and @a m_value.
+    */
+    void assert_invariant() const
+    {
+        assert(m_type != value_t::object or m_value.object != nullptr);
+        assert(m_type != value_t::array or m_value.array != nullptr);
+        assert(m_type != value_t::string or m_value.string != nullptr);
+    }
 
   public:
     //////////////////////////
@@ -915,6 +925,8 @@ class basic_json
     This enumeration lists the parser events that can trigger calling a
     callback function of type @ref parser_callback_t during parsing.
 
+    @image html callback_events.png "Example when certain parse events are triggered"
+
     @since version 1.0.0
     */
     enum class parse_event_t : uint8_t
@@ -937,12 +949,13 @@ class basic_json
     @brief per-element parser callback type
 
     With a parser callback function, the result of parsing a JSON text can be
-    influenced. When passed to @ref parse(std::istream&, parser_callback_t) or
-    @ref parse(const string_t&, parser_callback_t), it is called on certain
-    events (passed as @ref parse_event_t via parameter @a event) with a set
-    recursion depth @a depth and context JSON value @a parsed. The return
-    value of the callback function is a boolean indicating whether the element
-    that emitted the callback shall be kept or not.
+    influenced. When passed to @ref parse(std::istream&, const
+    parser_callback_t) or @ref parse(const string_t&, const parser_callback_t),
+    it is called on certain events (passed as @ref parse_event_t via parameter
+    @a event) with a set recursion depth @a depth and context JSON value
+    @a parsed. The return value of the callback function is a boolean
+    indicating whether the element that emitted the callback shall be kept or
+    not.
 
     We distinguish six scenarios (determined by the event type) in which the
     callback function can be called. The following table describes the values
@@ -957,6 +970,8 @@ class basic_json
     parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
     parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
 
+    @image html callback_events.png "Example when certain parse events are triggered"
+
     Discarding a value (i.e., returning `false`) has different effects
     depending on the context in which function was called:
 
@@ -982,7 +997,9 @@ class basic_json
 
     @since version 1.0.0
     */
-    using parser_callback_t = std::function<bool(int depth, parse_event_t event, basic_json& parsed)>;
+    using parser_callback_t = std::function<bool(int depth,
+                              parse_event_t event,
+                              basic_json& parsed)>;
 
 
     //////////////////
@@ -990,6 +1007,8 @@ class basic_json
     //////////////////
 
     /// @name constructors and destructors
+    /// Constructors of class @ref basic_json, copy/move constructor, copy
+    /// assignment, static functions creating objects, and the destructor.
     /// @{
 
     /*!
@@ -1033,7 +1052,9 @@ class basic_json
     */
     basic_json(const value_t value_type)
         : m_type(value_type), m_value(value_type)
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create a null object (implicitly)
@@ -1041,6 +1062,9 @@ class basic_json
     Create a `null` JSON value. This is the implicit version of the `null`
     value constructor as it takes no parameters.
 
+    @note The class invariant is satisfied, because it poses no requirements
+    for null values.
+
     @complexity Constant.
 
     @exceptionsafety No-throw guarantee: this constructor never throws
@@ -1085,7 +1109,9 @@ class basic_json
     */
     basic_json(std::nullptr_t) noexcept
         : basic_json(value_t::null)
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create an object (explicit)
@@ -1108,7 +1134,9 @@ class basic_json
     */
     basic_json(const object_t& val)
         : m_type(value_t::object), m_value(val)
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create an object (implicit)
@@ -1147,6 +1175,7 @@ class basic_json
         using std::begin;
         using std::end;
         m_value.object = create<object_t>(begin(val), end(val));
+        assert_invariant();
     }
 
     /*!
@@ -1170,7 +1199,9 @@ class basic_json
     */
     basic_json(const array_t& val)
         : m_type(value_t::array), m_value(val)
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create an array (implicit)
@@ -1214,6 +1245,7 @@ class basic_json
         using std::begin;
         using std::end;
         m_value.array = create<array_t>(begin(val), end(val));
+        assert_invariant();
     }
 
     /*!
@@ -1239,7 +1271,9 @@ class basic_json
     */
     basic_json(const string_t& val)
         : m_type(value_t::string), m_value(val)
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create a string (explicit)
@@ -1263,7 +1297,9 @@ class basic_json
     */
     basic_json(const typename string_t::value_type* val)
         : basic_json(string_t(val))
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create a string (implicit)
@@ -1294,7 +1330,9 @@ class basic_json
               = 0>
     basic_json(const CompatibleStringType& val)
         : basic_json(string_t(val))
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create a boolean (explicit)
@@ -1312,7 +1350,9 @@ class basic_json
     */
     basic_json(boolean_t val) noexcept
         : m_type(value_t::boolean), m_value(val)
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create an integer number (explicit)
@@ -1345,7 +1385,9 @@ class basic_json
              = 0>
     basic_json(const number_integer_t val) noexcept
         : m_type(value_t::number_integer), m_value(val)
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create an integer number from an enum type (explicit)
@@ -1375,7 +1417,9 @@ class basic_json
     basic_json(const int val) noexcept
         : m_type(value_t::number_integer),
           m_value(static_cast<number_integer_t>(val))
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create an integer number (implicit)
@@ -1412,15 +1456,17 @@ class basic_json
     basic_json(const CompatibleNumberIntegerType val) noexcept
         : m_type(value_t::number_integer),
           m_value(static_cast<number_integer_t>(val))
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create an unsigned integer number (explicit)
 
     Create an unsigned integer number JSON value with a given content.
 
-    @tparam T  helper type to compare number_unsigned_t and unsigned int
-    (not visible in) the interface.
+    @tparam T  helper type to compare number_unsigned_t and unsigned int (not
+    visible in) the interface.
 
     @param[in] val  an integer to create a JSON number from
 
@@ -1439,7 +1485,9 @@ class basic_json
              = 0>
     basic_json(const number_unsigned_t val) noexcept
         : m_type(value_t::number_unsigned), m_value(val)
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create an unsigned number (implicit)
@@ -1471,7 +1519,9 @@ class basic_json
     basic_json(const CompatibleNumberUnsignedType val) noexcept
         : m_type(value_t::number_unsigned),
           m_value(static_cast<number_unsigned_t>(val))
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create a floating-point number (explicit)
@@ -1484,8 +1534,8 @@ class basic_json
     disallows NaN values:
     > Numeric values that cannot be represented in the grammar below (such as
     > Infinity and NaN) are not permitted.
-    In case the parameter @a val is not a number, a JSON null value is
-    created instead.
+    In case the parameter @a val is not a number, a JSON null value is created
+    instead.
 
     @complexity Constant.
 
@@ -1506,6 +1556,8 @@ class basic_json
             m_type = value_t::null;
             m_value = json_value();
         }
+
+        assert_invariant();
     }
 
     /*!
@@ -1546,7 +1598,9 @@ class basic_json
              >
     basic_json(const CompatibleNumberFloatType val) noexcept
         : basic_json(number_float_t(val))
-    {}
+    {
+        assert_invariant();
+    }
 
     /*!
     @brief create a container (array or object) from an initializer list
@@ -1558,21 +1612,21 @@ class basic_json
 
     1. If the list is empty, an empty JSON object value `{}` is created.
     2. If the list consists of pairs whose first element is a string, a JSON
-    object value is created where the first elements of the pairs are treated
-    as keys and the second elements are as values.
+       object value is created where the first elements of the pairs are
+       treated as keys and the second elements are as values.
     3. In all other cases, an array is created.
 
     The rules aim to create the best fit between a C++ initializer list and
     JSON values. The rationale is as follows:
 
     1. The empty initializer list is written as `{}` which is exactly an empty
-    JSON object.
+       JSON object.
     2. C++ has now way of describing mapped types other than to list a list of
-    pairs. As JSON requires that keys must be of type string, rule 2 is the
-    weakest constraint one can pose on initializer lists to interpret them as
-    an object.
+       pairs. As JSON requires that keys must be of type string, rule 2 is the
+       weakest constraint one can pose on initializer lists to interpret them
+       as an object.
     3. In all other cases, the initializer list could not be interpreted as
-    JSON object type, so interpreting it as JSON array type is safe.
+       JSON object type, so interpreting it as JSON array type is safe.
 
     With the rules described above, the following JSON values cannot be
     expressed by an initializer list:
@@ -1621,22 +1675,13 @@ class basic_json
                bool type_deduction = true,
                value_t manual_type = value_t::array)
     {
-        // the initializer list could describe an object
-        bool is_an_object = true;
-
         // check if each element is an array with two elements whose first
         // element is a string
-        for (const auto& element : init)
+        bool is_an_object = std::all_of(init.begin(), init.end(),
+                                        [](const basic_json & element)
         {
-            if (not element.is_array() or element.size() != 2
-                    or not element[0].is_string())
-            {
-                // we found an element that makes it impossible to use the
-                // initializer list as object
-                is_an_object = false;
-                break;
-            }
-        }
+            return element.is_array() and element.size() == 2 and element[0].is_string();
+        });
 
         // adjust type if type deduction is not wanted
         if (not type_deduction)
@@ -1660,12 +1705,10 @@ class basic_json
             m_type = value_t::object;
             m_value = value_t::object;
 
-            assert(m_value.object != nullptr);
-
-            for (auto& element : init)
+            std::for_each(init.begin(), init.end(), [this](const basic_json & element)
             {
                 m_value.object->emplace(*(element[0].m_value.string), element[1]);
-            }
+            });
         }
         else
         {
@@ -1673,6 +1716,8 @@ class basic_json
             m_type = value_t::array;
             m_value.array = create<array_t>(init);
         }
+
+        assert_invariant();
     }
 
     /*!
@@ -1777,6 +1822,7 @@ class basic_json
         : m_type(value_t::array)
     {
         m_value.array = create<array_t>(cnt, val);
+        assert_invariant();
     }
 
     /*!
@@ -1797,6 +1843,8 @@ class basic_json
     @param[in] first begin of the range to copy from (included)
     @param[in] last end of the range to copy from (excluded)
 
+    @pre Iterators @a first and @a last must be initialized.
+
     @throw std::domain_error if iterators are not compatible; that is, do not
     belong to the same JSON value; example: `"iterators are not compatible"`
     @throw std::out_of_range if iterators are for a primitive type (number,
@@ -1819,14 +1867,20 @@ class basic_json
                   std::is_same<InputIT, typename basic_json_t::const_iterator>::value
                   , int>::type
               = 0>
-    basic_json(InputIT first, InputIT last) : m_type(first.m_object->m_type)
+    basic_json(InputIT first, InputIT last)
     {
+        assert(first.m_object != nullptr);
+        assert(last.m_object != nullptr);
+
         // make sure iterator fits the current value
         if (first.m_object != last.m_object)
         {
             throw std::domain_error("iterators are not compatible");
         }
 
+        // copy type from first iterator
+        m_type = first.m_object->m_type;
+
         // check if iterator range is complete for primitive values
         switch (m_type)
         {
@@ -1853,35 +1907,30 @@ class basic_json
         {
             case value_t::number_integer:
             {
-                assert(first.m_object != nullptr);
                 m_value.number_integer = first.m_object->m_value.number_integer;
                 break;
             }
 
             case value_t::number_unsigned:
             {
-                assert(first.m_object != nullptr);
                 m_value.number_unsigned = first.m_object->m_value.number_unsigned;
                 break;
             }
 
             case value_t::number_float:
             {
-                assert(first.m_object != nullptr);
                 m_value.number_float = first.m_object->m_value.number_float;
                 break;
             }
 
             case value_t::boolean:
             {
-                assert(first.m_object != nullptr);
                 m_value.boolean = first.m_object->m_value.boolean;
                 break;
             }
 
             case value_t::string:
             {
-                assert(first.m_object != nullptr);
                 m_value = *first.m_object->m_value.string;
                 break;
             }
@@ -1900,10 +1949,11 @@ class basic_json
 
             default:
             {
-                assert(first.m_object != nullptr);
                 throw std::domain_error("cannot use construct with iterators from " + first.m_object->type_name());
             }
         }
+
+        assert_invariant();
     }
 
     /*!
@@ -1926,9 +1976,10 @@ class basic_json
 
     @since version 2.0.0
     */
-    explicit basic_json(std::istream& i, parser_callback_t cb = nullptr)
+    explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)
     {
         *this = parser(i, cb).parse();
+        assert_invariant();
     }
 
     ///////////////////////////////////////
@@ -1960,25 +2011,25 @@ class basic_json
     basic_json(const basic_json& other)
         : m_type(other.m_type)
     {
+        // check of passed value is valid
+        other.assert_invariant();
+
         switch (m_type)
         {
             case value_t::object:
             {
-                assert(other.m_value.object != nullptr);
                 m_value = *other.m_value.object;
                 break;
             }
 
             case value_t::array:
             {
-                assert(other.m_value.array != nullptr);
                 m_value = *other.m_value.array;
                 break;
             }
 
             case value_t::string:
             {
-                assert(other.m_value.string != nullptr);
                 m_value = *other.m_value.string;
                 break;
             }
@@ -2012,6 +2063,8 @@ class basic_json
                 break;
             }
         }
+
+        assert_invariant();
     }
 
     /*!
@@ -2036,9 +2089,14 @@ class basic_json
         : m_type(std::move(other.m_type)),
           m_value(std::move(other.m_value))
     {
+        // check that passed value is valid
+        other.assert_invariant();
+
         // invalidate payload
         other.m_type = value_t::null;
         other.m_value = {};
+
+        assert_invariant();
     }
 
     /*!
@@ -2071,9 +2129,14 @@ class basic_json
         std::is_nothrow_move_assignable<json_value>::value
     )
     {
+        // check that passed value is valid
+        other.assert_invariant();
+
         using std::swap;
         swap(m_type, other.m_type);
         swap(m_value, other.m_value);
+
+        assert_invariant();
         return *this;
     }
 
@@ -2094,6 +2157,8 @@ class basic_json
     */
     ~basic_json()
     {
+        assert_invariant();
+
         switch (m_type)
         {
             case value_t::object:
@@ -2136,19 +2201,20 @@ class basic_json
     ///////////////////////
 
     /// @name object inspection
+    /// Functions to inspect the type of a JSON value.
     /// @{
 
     /*!
     @brief serialization
 
     Serialization function for JSON values. The function tries to mimic
-    Python's @p json.dumps() function, and currently supports its @p indent
+    Python's `json.dumps()` function, and currently supports its @a indent
     parameter.
 
-    @param[in] indent if indent is nonnegative, then array elements and object
+    @param[in] indent If indent is nonnegative, then array elements and object
     members will be pretty-printed with that indent level. An indent level of
-    0 will only insert newlines. -1 (the default) selects the most compact
-    representation
+    `0` will only insert newlines. `-1` (the default) selects the most compact
+    representation.
 
     @return string containing the serialization of the JSON value
 
@@ -2164,6 +2230,14 @@ class basic_json
     string_t dump(const int indent = -1) const
     {
         std::stringstream ss;
+        // fix locale problems
+        ss.imbue(std::locale(std::locale(), new DecimalSeparator));
+
+        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
+        // string->float->string, string->double->string or string->long
+        // double->string; to be safe, we read this value from
+        // std::numeric_limits<number_float_t>::digits10
+        ss.precision(std::numeric_limits<double>::digits10);
 
         if (indent >= 0)
         {
@@ -2549,7 +2623,6 @@ class basic_json
     {
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             return T(m_value.object->begin(), m_value.object->end());
         }
         else
@@ -2563,7 +2636,6 @@ class basic_json
     {
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             return *(m_value.object);
         }
         else
@@ -2586,7 +2658,6 @@ class basic_json
         if (is_array())
         {
             T to_vector;
-            assert(m_value.array != nullptr);
             std::transform(m_value.array->begin(), m_value.array->end(),
                            std::inserter(to_vector, to_vector.end()), [](basic_json i)
             {
@@ -2611,7 +2682,6 @@ class basic_json
         if (is_array())
         {
             std::vector<T> to_vector;
-            assert(m_value.array != nullptr);
             to_vector.reserve(m_value.array->size());
             std::transform(m_value.array->begin(), m_value.array->end(),
                            std::inserter(to_vector, to_vector.end()), [](basic_json i)
@@ -2636,7 +2706,6 @@ class basic_json
     {
         if (is_array())
         {
-            assert(m_value.array != nullptr);
             return T(m_value.array->begin(), m_value.array->end());
         }
         else
@@ -2650,7 +2719,6 @@ class basic_json
     {
         if (is_array())
         {
-            assert(m_value.array != nullptr);
             return *(m_value.array);
         }
         else
@@ -2668,7 +2736,6 @@ class basic_json
     {
         if (is_string())
         {
-            assert(m_value.string != nullptr);
             return *m_value.string;
         }
         else
@@ -2814,8 +2881,10 @@ class basic_json
     template<typename ReferenceType, typename ThisType>
     static ReferenceType get_ref_impl(ThisType& obj)
     {
-        // delegate the call to get_ptr<>()
+        // helper type
         using PointerType = typename std::add_pointer<ReferenceType>::type;
+
+        // delegate the call to get_ptr<>()
         auto ptr = obj.template get_ptr<PointerType>();
 
         if (ptr != nullptr)
@@ -2832,6 +2901,7 @@ class basic_json
   public:
 
     /// @name value access
+    /// Direct access to the stored value of a JSON value.
     /// @{
 
     /*!
@@ -2882,7 +2952,8 @@ class basic_json
     Explicit pointer access to the internally stored JSON value. No copies are
     made.
 
-    @warning The pointer becomes invalid if the underlying JSON object changes.
+    @warning The pointer becomes invalid if the underlying JSON object
+    changes.
 
     @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
     object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
@@ -2937,7 +3008,8 @@ class basic_json
 
     @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
     object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
-    @ref number_unsigned_t, or @ref number_float_t.
+    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
+    assertion.
 
     @return pointer to the internally stored JSON value if the requested
     pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
@@ -2957,6 +3029,21 @@ class basic_json
                  , int>::type = 0>
     PointerType get_ptr() noexcept
     {
+        // get the type of the PointerType (remove pointer and const)
+        using pointee_t = typename std::remove_const<typename
+                          std::remove_pointer<typename
+                          std::remove_const<PointerType>::type>::type>::type;
+        // make sure the type matches the allowed types
+        static_assert(
+            std::is_same<object_t, pointee_t>::value
+            or std::is_same<array_t, pointee_t>::value
+            or std::is_same<string_t, pointee_t>::value
+            or std::is_same<boolean_t, pointee_t>::value
+            or std::is_same<number_integer_t, pointee_t>::value
+            or std::is_same<number_unsigned_t, pointee_t>::value
+            or std::is_same<number_float_t, pointee_t>::value
+            , "incompatible pointer type");
+
         // delegate the call to get_impl_ptr<>()
         return get_impl_ptr(static_cast<PointerType>(nullptr));
     }
@@ -2972,6 +3059,21 @@ class basic_json
                  , int>::type = 0>
     constexpr const PointerType get_ptr() const noexcept
     {
+        // get the type of the PointerType (remove pointer and const)
+        using pointee_t = typename std::remove_const<typename
+                          std::remove_pointer<typename
+                          std::remove_const<PointerType>::type>::type>::type;
+        // make sure the type matches the allowed types
+        static_assert(
+            std::is_same<object_t, pointee_t>::value
+            or std::is_same<array_t, pointee_t>::value
+            or std::is_same<string_t, pointee_t>::value
+            or std::is_same<boolean_t, pointee_t>::value
+            or std::is_same<number_integer_t, pointee_t>::value
+            or std::is_same<number_unsigned_t, pointee_t>::value
+            or std::is_same<number_float_t, pointee_t>::value
+            , "incompatible pointer type");
+
         // delegate the call to get_impl_ptr<>() const
         return get_impl_ptr(static_cast<const PointerType>(nullptr));
     }
@@ -2987,7 +3089,7 @@ class basic_json
 
     @tparam ReferenceType reference type; must be a reference to @ref array_t,
     @ref object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, or
-    @ref number_float_t.
+    @ref number_float_t. Enforced by static assertion.
 
     @return reference to the internally stored JSON value if the requested
     reference type @a ReferenceType fits to the JSON value; throws
@@ -3077,6 +3179,7 @@ class basic_json
     ////////////////////
 
     /// @name element access
+    /// Access to the JSON value.
     /// @{
 
     /*!
@@ -3108,7 +3211,6 @@ class basic_json
         {
             try
             {
-                assert(m_value.array != nullptr);
                 return m_value.array->at(idx);
             }
             catch (std::out_of_range&)
@@ -3152,7 +3254,6 @@ class basic_json
         {
             try
             {
-                assert(m_value.array != nullptr);
                 return m_value.array->at(idx);
             }
             catch (std::out_of_range&)
@@ -3200,7 +3301,6 @@ class basic_json
         {
             try
             {
-                assert(m_value.object != nullptr);
                 return m_value.object->at(key);
             }
             catch (std::out_of_range&)
@@ -3248,7 +3348,6 @@ class basic_json
         {
             try
             {
-                assert(m_value.object != nullptr);
                 return m_value.object->at(key);
             }
             catch (std::out_of_range&)
@@ -3295,16 +3394,18 @@ class basic_json
         {
             m_type = value_t::array;
             m_value.array = create<array_t>();
+            assert_invariant();
         }
 
         // operator[] only works for arrays
         if (is_array())
         {
-            // fill up array with null values until given idx is reached
-            assert(m_value.array != nullptr);
-            for (size_t i = m_value.array->size(); i <= idx; ++i)
+            // fill up array with null values if given idx is outside range
+            if (idx >= m_value.array->size())
             {
-                m_value.array->push_back(basic_json());
+                m_value.array->insert(m_value.array->end(),
+                                      idx - m_value.array->size() + 1,
+                                      basic_json());
             }
 
             return m_value.array->operator[](idx);
@@ -3339,7 +3440,6 @@ class basic_json
         // const operator[] only works for arrays
         if (is_array())
         {
-            assert(m_value.array != nullptr);
             return m_value.array->operator[](idx);
         }
         else
@@ -3382,12 +3482,12 @@ class basic_json
         {
             m_type = value_t::object;
             m_value.object = create<object_t>();
+            assert_invariant();
         }
 
         // operator[] only works for objects
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             return m_value.object->operator[](key);
         }
         else
@@ -3428,7 +3528,6 @@ class basic_json
         // const operator[] only works for objects
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             assert(m_value.object->find(key) != m_value.object->end());
             return m_value.object->find(key)->second;
         }
@@ -3541,12 +3640,12 @@ class basic_json
         {
             m_type = value_t::object;
             m_value = value_t::object;
+            assert_invariant();
         }
 
         // at only works for objects
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             return m_value.object->operator[](key);
         }
         else
@@ -3588,7 +3687,6 @@ class basic_json
         // at only works for objects
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             assert(m_value.object->find(key) != m_value.object->end());
             return m_value.object->find(key)->second;
         }
@@ -3601,8 +3699,8 @@ class basic_json
     /*!
     @brief access specified object element with default value
 
-    Returns either a copy of an object's element at the specified key @a key or
-    a given default value if no element with key @a key exists.
+    Returns either a copy of an object's element at the specified key @a key
+    or a given default value if no element with key @a key exists.
 
     The function is basically equivalent to executing
     @code {.cpp}
@@ -3674,13 +3772,88 @@ class basic_json
 
     /*!
     @brief overload for a default value of type const char*
-    @copydoc basic_json::value()
+    @copydoc basic_json::value(const typename object_t::key_type&, ValueType) const
     */
     string_t value(const typename object_t::key_type& key, const char* default_value) const
     {
         return value(key, string_t(default_value));
     }
 
+    /*!
+    @brief access specified object element via JSON Pointer with default value
+
+    Returns either a copy of an object's element at the specified key @a key
+    or a given default value if no element with key @a key exists.
+
+    The function is basically equivalent to executing
+    @code {.cpp}
+    try {
+        return at(ptr);
+    } catch(std::out_of_range) {
+        return default_value;
+    }
+    @endcode
+
+    @note Unlike @ref at(const json_pointer&), this function does not throw
+    if the given key @a key was not found.
+
+    @param[in] ptr  a JSON pointer to the element to access
+    @param[in] default_value  the value to return if @a ptr found no value
+
+    @tparam ValueType type compatible to JSON values, for instance `int` for
+    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
+    JSON arrays. Note the type of the expected value at @a key and the default
+    value @a default_value must be compatible.
+
+    @return copy of the element at key @a key or @a default_value if @a key
+    is not found
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    value() with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be queried
+    with a default value.,basic_json__value_ptr}
+
+    @sa @ref operator[](const json_pointer&) for unchecked access by reference
+
+    @since version 2.0.2
+    */
+    template <class ValueType, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, ValueType>::value
+                  , int>::type = 0>
+    ValueType value(const json_pointer& ptr, ValueType default_value) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            // if pointer resolves a value, return it or use default value
+            try
+            {
+                return ptr.get_checked(this);
+            }
+            catch (std::out_of_range&)
+            {
+                return default_value;
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use value() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief overload for a default value of type const char*
+    @copydoc basic_json::value(const json_pointer&, ValueType) const
+    */
+    string_t value(const json_pointer& ptr, const char* default_value) const
+    {
+        return value(ptr, string_t(default_value));
+    }
+
     /*!
     @brief access the first element
 
@@ -3840,24 +4013,25 @@ class basic_json
 
                 if (is_string())
                 {
-                    delete m_value.string;
+                    AllocatorType<string_t> alloc;
+                    alloc.destroy(m_value.string);
+                    alloc.deallocate(m_value.string, 1);
                     m_value.string = nullptr;
                 }
 
                 m_type = value_t::null;
+                assert_invariant();
                 break;
             }
 
             case value_t::object:
             {
-                assert(m_value.object != nullptr);
                 result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator);
                 break;
             }
 
             case value_t::array:
             {
-                assert(m_value.array != nullptr);
                 result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator);
                 break;
             }
@@ -3948,17 +4122,19 @@ class basic_json
 
                 if (is_string())
                 {
-                    delete m_value.string;
+                    AllocatorType<string_t> alloc;
+                    alloc.destroy(m_value.string);
+                    alloc.deallocate(m_value.string, 1);
                     m_value.string = nullptr;
                 }
 
                 m_type = value_t::null;
+                assert_invariant();
                 break;
             }
 
             case value_t::object:
             {
-                assert(m_value.object != nullptr);
                 result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator,
                                               last.m_it.object_iterator);
                 break;
@@ -3966,7 +4142,6 @@ class basic_json
 
             case value_t::array:
             {
-                assert(m_value.array != nullptr);
                 result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator,
                                              last.m_it.array_iterator);
                 break;
@@ -4015,7 +4190,6 @@ class basic_json
         // this erase only works for objects
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             return m_value.object->erase(key);
         }
         else
@@ -4058,7 +4232,6 @@ class basic_json
                 throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
             }
 
-            assert(m_value.array != nullptr);
             m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
         }
         else
@@ -4101,7 +4274,6 @@ class basic_json
 
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             result.m_it.object_iterator = m_value.object->find(key);
         }
 
@@ -4118,7 +4290,6 @@ class basic_json
 
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             result.m_it.object_iterator = m_value.object->find(key);
         }
 
@@ -4146,7 +4317,6 @@ class basic_json
     size_type count(typename object_t::key_type key) const
     {
         // return 0 for all nonobject types
-        assert(not is_object() or m_value.object != nullptr);
         return is_object() ? m_value.object->count(key) : 0;
     }
 
@@ -4488,6 +4658,10 @@ class basic_json
             object      | result of function `object_t::empty()`
             array       | result of function `array_t::empty()`
 
+    @note This function does not return whether a string stored as JSON value
+    is empty - it returns whether the JSON container itself is empty which is
+    false in the case of a string.
+
     @complexity Constant, as long as @ref array_t and @ref object_t satisfy
     the Container concept; that is, their `empty()` functions have constant
     complexity.
@@ -4517,13 +4691,13 @@ class basic_json
 
             case value_t::array:
             {
-                assert(m_value.array != nullptr);
+                // delegate call to array_t::empty()
                 return m_value.array->empty();
             }
 
             case value_t::object:
             {
-                assert(m_value.object != nullptr);
+                // delegate call to object_t::empty()
                 return m_value.object->empty();
             }
 
@@ -4551,6 +4725,10 @@ class basic_json
             object      | result of function object_t::size()
             array       | result of function array_t::size()
 
+    @note This function does not return the length of a string stored as JSON
+    value - it returns the number of elements in the JSON value which is 1 in
+    the case of a string.
+
     @complexity Constant, as long as @ref array_t and @ref object_t satisfy
     the Container concept; that is, their size() functions have constant
     complexity.
@@ -4581,13 +4759,13 @@ class basic_json
 
             case value_t::array:
             {
-                assert(m_value.array != nullptr);
+                // delegate call to array_t::size()
                 return m_value.array->size();
             }
 
             case value_t::object:
             {
-                assert(m_value.object != nullptr);
+                // delegate call to object_t::size()
                 return m_value.object->size();
             }
 
@@ -4641,13 +4819,13 @@ class basic_json
         {
             case value_t::array:
             {
-                assert(m_value.array != nullptr);
+                // delegate call to array_t::max_size()
                 return m_value.array->max_size();
             }
 
             case value_t::object:
             {
-                assert(m_value.object != nullptr);
+                // delegate call to object_t::max_size()
                 return m_value.object->max_size();
             }
 
@@ -4724,21 +4902,18 @@ class basic_json
 
             case value_t::string:
             {
-                assert(m_value.string != nullptr);
                 m_value.string->clear();
                 break;
             }
 
             case value_t::array:
             {
-                assert(m_value.array != nullptr);
                 m_value.array->clear();
                 break;
             }
 
             case value_t::object:
             {
-                assert(m_value.object != nullptr);
                 m_value.object->clear();
                 break;
             }
@@ -4783,10 +4958,10 @@ class basic_json
         {
             m_type = value_t::array;
             m_value = value_t::array;
+            assert_invariant();
         }
 
         // add element to array (move semantics)
-        assert(m_value.array != nullptr);
         m_value.array->push_back(std::move(val));
         // invalidate object
         val.m_type = value_t::null;
@@ -4819,10 +4994,10 @@ class basic_json
         {
             m_type = value_t::array;
             m_value = value_t::array;
+            assert_invariant();
         }
 
         // add element to array
-        assert(m_value.array != nullptr);
         m_value.array->push_back(val);
     }
 
@@ -4869,10 +5044,10 @@ class basic_json
         {
             m_type = value_t::object;
             m_value = value_t::object;
+            assert_invariant();
         }
 
         // add element to array
-        assert(m_value.object != nullptr);
         m_value.object->insert(val);
     }
 
@@ -4969,7 +5144,6 @@ class basic_json
 
             // insert to array and return iterator
             iterator result(this);
-            assert(m_value.array != nullptr);
             result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
             return result;
         }
@@ -5025,7 +5199,6 @@ class basic_json
 
             // insert to array and return iterator
             iterator result(this);
-            assert(m_value.array != nullptr);
             result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
             return result;
         }
@@ -5092,7 +5265,6 @@ class basic_json
 
         // insert to array and return iterator
         iterator result(this);
-        assert(m_value.array != nullptr);
         result.m_it.array_iterator = m_value.array->insert(
                                          pos.m_it.array_iterator,
                                          first.m_it.array_iterator,
@@ -5140,7 +5312,6 @@ class basic_json
 
         // insert to array and return iterator
         iterator result(this);
-        assert(m_value.array != nullptr);
         result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, ilist);
         return result;
     }
@@ -5171,6 +5342,7 @@ class basic_json
     {
         std::swap(m_type, other.m_type);
         std::swap(m_value, other.m_value);
+        assert_invariant();
     }
 
     /*!
@@ -5198,7 +5370,6 @@ class basic_json
         // swap only works for arrays
         if (is_array())
         {
-            assert(m_value.array != nullptr);
             std::swap(*(m_value.array), other);
         }
         else
@@ -5232,7 +5403,6 @@ class basic_json
         // swap only works for objects
         if (is_object())
         {
-            assert(m_value.object != nullptr);
             std::swap(*(m_value.object), other);
         }
         else
@@ -5266,7 +5436,6 @@ class basic_json
         // swap only works for strings
         if (is_string())
         {
-            assert(m_value.string != nullptr);
             std::swap(*(m_value.string), other);
         }
         else
@@ -5353,14 +5522,10 @@ class basic_json
             {
                 case value_t::array:
                 {
-                    assert(lhs.m_value.array != nullptr);
-                    assert(rhs.m_value.array != nullptr);
                     return *lhs.m_value.array == *rhs.m_value.array;
                 }
                 case value_t::object:
                 {
-                    assert(lhs.m_value.object != nullptr);
-                    assert(rhs.m_value.object != nullptr);
                     return *lhs.m_value.object == *rhs.m_value.object;
                 }
                 case value_t::null:
@@ -5369,8 +5534,6 @@ class basic_json
                 }
                 case value_t::string:
                 {
-                    assert(lhs.m_value.string != nullptr);
-                    assert(rhs.m_value.string != nullptr);
                     return *lhs.m_value.string == *rhs.m_value.string;
                 }
                 case value_t::boolean:
@@ -5543,14 +5706,10 @@ class basic_json
             {
                 case value_t::array:
                 {
-                    assert(lhs.m_value.array != nullptr);
-                    assert(rhs.m_value.array != nullptr);
                     return *lhs.m_value.array < *rhs.m_value.array;
                 }
                 case value_t::object:
                 {
-                    assert(lhs.m_value.object != nullptr);
-                    assert(rhs.m_value.object != nullptr);
                     return *lhs.m_value.object < *rhs.m_value.object;
                 }
                 case value_t::null:
@@ -5559,8 +5718,6 @@ class basic_json
                 }
                 case value_t::string:
                 {
-                    assert(lhs.m_value.string != nullptr);
-                    assert(rhs.m_value.string != nullptr);
                     return *lhs.m_value.string < *rhs.m_value.string;
                 }
                 case value_t::boolean:
@@ -5702,6 +5859,10 @@ class basic_json
     `std::setw(4)` on @a o sets the indentation level to `4` and the
     serialization result is the same as calling `dump(4)`.
 
+    @note During serializaion, the locale and the precision of the output
+    stream @a o are changed. The original values are restored when the
+    function returns.
+
     @param[in,out] o  stream to serialize to
     @param[in] j  JSON value to serialize
 
@@ -5723,8 +5884,22 @@ class basic_json
         // reset width to 0 for subsequent calls to this stream
         o.width(0);
 
+        // fix locale problems
+        const auto old_locale = o.imbue(std::locale(std::locale(), new DecimalSeparator));
+        // set precision
+
+        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
+        // string->float->string, string->double->string or string->long
+        // double->string; to be safe, we read this value from
+        // std::numeric_limits<number_float_t>::digits10
+        const auto old_precision = o.precision(std::numeric_limits<double>::digits10);
+
         // do the actual serialization
         j.dump(o, pretty_print, static_cast<unsigned int>(indentation));
+
+        // reset locale and precision
+        o.imbue(old_locale);
+        o.precision(old_precision);
         return o;
     }
 
@@ -5766,12 +5941,13 @@ class basic_json
     @liveexample{The example below demonstrates the `parse()` function with
     and without callback function.,parse__string__parser_callback_t}
 
-    @sa @ref parse(std::istream&, parser_callback_t) for a version that reads
-    from an input stream
+    @sa @ref parse(std::istream&, const parser_callback_t) for a version that
+    reads from an input stream
 
     @since version 1.0.0
     */
-    static basic_json parse(const string_t& s, parser_callback_t cb = nullptr)
+    static basic_json parse(const string_t& s,
+                            const parser_callback_t cb = nullptr)
     {
         return parser(s, cb).parse();
     }
@@ -5795,20 +5971,22 @@ class basic_json
     @liveexample{The example below demonstrates the `parse()` function with
     and without callback function.,parse__istream__parser_callback_t}
 
-    @sa @ref parse(const string_t&, parser_callback_t) for a version that
-    reads from a string
+    @sa @ref parse(const string_t&, const parser_callback_t) for a version
+    that reads from a string
 
     @since version 1.0.0
     */
-    static basic_json parse(std::istream& i, parser_callback_t cb = nullptr)
+    static basic_json parse(std::istream& i,
+                            const parser_callback_t cb = nullptr)
     {
         return parser(i, cb).parse();
     }
 
     /*!
-    @copydoc parse(std::istream&, parser_callback_t)
+    @copydoc parse(std::istream&, const parser_callback_t)
     */
-    static basic_json parse(std::istream&& i, parser_callback_t cb = nullptr)
+    static basic_json parse(std::istream&& i,
+                            const parser_callback_t cb = nullptr)
     {
         return parser(i, cb).parse();
     }
@@ -5831,8 +6009,8 @@ class basic_json
     @liveexample{The example below shows how a JSON value is constructed by
     reading a serialization from a stream.,operator_deserialize}
 
-    @sa parse(std::istream&, parser_callback_t) for a variant with a parser
-    callback function to filter values while parsing
+    @sa parse(std::istream&, const parser_callback_t) for a variant with a
+    parser callback function to filter values while parsing
 
     @since version 1.0.0
     */
@@ -5860,8 +6038,19 @@ class basic_json
     // convenience functions //
     ///////////////////////////
 
-    /// return the type as string
-    string_t type_name() const noexcept
+    /*!
+    @brief return the type as string
+
+    Returns the type name as string to be used in error messages - usually to
+    indicate that a function was called on a wrong JSON type.
+
+    @return basically a string representation of a the @ref m_type member
+
+    @complexity Constant.
+
+    @since version 1.0.0
+    */
+    std::string type_name() const
     {
         switch (m_type)
         {
@@ -5892,9 +6081,8 @@ class basic_json
     */
     static std::size_t extra_space(const string_t& s) noexcept
     {
-        std::size_t result = 0;
-
-        for (const auto& c : s)
+        return std::accumulate(s.begin(), s.end(), size_t{},
+                               [](size_t res, typename string_t::value_type c)
         {
             switch (c)
             {
@@ -5907,8 +6095,7 @@ class basic_json
                 case '\t':
                 {
                     // from c (1 byte) to \x (2 bytes)
-                    result += 1;
-                    break;
+                    return res + 1;
                 }
 
                 default:
@@ -5916,14 +6103,15 @@ class basic_json
                     if (c >= 0x00 and c <= 0x1f)
                     {
                         // from c (1 byte) to \uxxxx (6 bytes)
-                        result += 5;
+                        return res + 5;
+                    }
+                    else
+                    {
+                        return res;
                     }
-                    break;
                 }
             }
-        }
-
-        return result;
+        });
     }
 
     /*!
@@ -6017,16 +6205,15 @@ class basic_json
                     {
                         // convert a number 0..15 to its hex representation
                         // (0..f)
-                        const auto hexify = [](const int v) -> char
+                        static const char hexify[16] =
                         {
-                            return (v < 10)
-                            ? ('0' + static_cast<char>(v))
-                            : ('a' + static_cast<char>((v - 10) & 0x1f));
+                            '0', '1', '2', '3', '4', '5', '6', '7',
+                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
                         };
 
                         // print character c as \uxxxx
                         for (const char m :
-                    { 'u', '0', '0', hexify(c >> 4), hexify(c & 0x0f)
+                    { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f]
                         })
                         {
                             result[++pos] = m;
@@ -6076,8 +6263,6 @@ class basic_json
         {
             case value_t::object:
             {
-                assert(m_value.object != nullptr);
-
                 if (m_value.object->empty())
                 {
                     o << "{}";
@@ -6118,8 +6303,6 @@ class basic_json
 
             case value_t::array:
             {
-                assert(m_value.array != nullptr);
-
                 if (m_value.array->empty())
                 {
                     o << "[]";
@@ -6158,7 +6341,6 @@ class basic_json
 
             case value_t::string:
             {
-                assert(m_value.string != nullptr);
                 o << string_t("\"") << escape_string(*m_value.string) << "\"";
                 return;
             }
@@ -6183,79 +6365,14 @@ class basic_json
 
             case value_t::number_float:
             {
-                // check if number was parsed from a string
-                if (m_type.bits.parsed)
+                if (m_value.number_float == 0)
                 {
-                    // check if parsed number had an exponent given
-                    if (m_type.bits.has_exp)
-                    {
-                        // buffer size: precision (2^8-1 = 255) + other ('-.e-xxx' = 7) + null (1)
-                        char buf[263];
-                        int len;
-
-                        // handle capitalization of the exponent
-                        if (m_type.bits.exp_cap)
-                        {
-                            len = snprintf(buf, sizeof(buf), "%.*E",
-                                           m_type.bits.precision, m_value.number_float) + 1;
-                        }
-                        else
-                        {
-                            len = snprintf(buf, sizeof(buf), "%.*e",
-                                           m_type.bits.precision, m_value.number_float) + 1;
-                        }
-
-                        // remove '+' sign from the exponent if necessary
-                        if (not m_type.bits.exp_plus)
-                        {
-                            if (len > static_cast<int>(sizeof(buf)))
-                            {
-                                len = sizeof(buf);
-                            }
-                            for (int i = 0; i < len; i++)
-                            {
-                                if (buf[i] == '+')
-                                {
-                                    for (; i + 1 < len; i++)
-                                    {
-                                        buf[i] = buf[i + 1];
-                                    }
-                                }
-                            }
-                        }
-
-                        o << buf;
-                    }
-                    else
-                    {
-                        // no exponent - output as a decimal
-                        std::stringstream ss;
-                        ss.imbue(std::locale(std::locale(), new DecimalSeparator));  // fix locale problems
-                        ss << std::setprecision(m_type.bits.precision)
-                           << std::fixed << m_value.number_float;
-                        o << ss.str();
-                    }
+                    // special case for zero to get "0.0"/"-0.0"
+                    o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
                 }
                 else
                 {
-                    if (m_value.number_float == 0)
-                    {
-                        // special case for zero to get "0.0"/"-0.0"
-                        o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
-                    }
-                    else
-                    {
-                        // Otherwise 6, 15 or 16 digits of precision allows
-                        // round-trip IEEE 754 string->float->string,
-                        // string->double->string or string->long
-                        // double->string; to be safe, we read this value from
-                        // std::numeric_limits<number_float_t>::digits10
-                        std::stringstream ss;
-                        ss.imbue(std::locale(std::locale(), new DecimalSeparator));  // fix locale problems
-                        ss << std::setprecision(std::numeric_limits<double>::digits10)
-                           << m_value.number_float;
-                        o << ss.str();
-                    }
+                    o << m_value.number_float;
                 }
                 return;
             }
@@ -6280,7 +6397,7 @@ class basic_json
     //////////////////////
 
     /// the type of the current element
-    type_data_t m_type = value_t::null;
+    value_t m_type = value_t::null;
 
     /// the value of the current element
     json_value m_value = {};
@@ -6472,6 +6589,12 @@ class basic_json
     This class implements a const iterator for the @ref basic_json class. From
     this class, the @ref iterator class is derived.
 
+    @note An iterator is called *initialized* when a pointer to a JSON value
+          has been set (e.g., by a constructor or a copy assignment). If the
+          iterator is default-constructed, it is *uninitialized* and most
+          methods are undefined. The library uses assertions to detect calls
+          on uninitialized iterators.
+
     @requirement The class satisfies the following concept requirements:
     - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
       The iterator that can be moved to point (forward and backward) to any
@@ -6499,7 +6622,12 @@ class basic_json
         /// default constructor
         const_iterator() = default;
 
-        /// constructor for a given JSON instance
+        /*!
+        @brief constructor for a given JSON instance
+        @param[in] object  pointer to a JSON object for this iterator
+        @pre object != nullptr
+        @post The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         explicit const_iterator(pointer object) noexcept
             : m_object(object)
         {
@@ -6527,40 +6655,53 @@ class basic_json
             }
         }
 
-        /// copy constructor given a nonconst iterator
+        /*!
+        @brief copy constructor given a non-const iterator
+        @param[in] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
         explicit const_iterator(const iterator& other) noexcept
             : m_object(other.m_object)
         {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
+            if (m_object != nullptr)
             {
-                case basic_json::value_t::object:
+                switch (m_object->m_type)
                 {
-                    m_it.object_iterator = other.m_it.object_iterator;
-                    break;
-                }
+                    case basic_json::value_t::object:
+                    {
+                        m_it.object_iterator = other.m_it.object_iterator;
+                        break;
+                    }
 
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = other.m_it.array_iterator;
-                    break;
-                }
+                    case basic_json::value_t::array:
+                    {
+                        m_it.array_iterator = other.m_it.array_iterator;
+                        break;
+                    }
 
-                default:
-                {
-                    m_it.primitive_iterator = other.m_it.primitive_iterator;
-                    break;
+                    default:
+                    {
+                        m_it.primitive_iterator = other.m_it.primitive_iterator;
+                        break;
+                    }
                 }
             }
         }
 
-        /// copy constructor
+        /*!
+        @brief copy constructor
+        @param[in] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
         const_iterator(const const_iterator& other) noexcept
             : m_object(other.m_object), m_it(other.m_it)
         {}
 
-        /// copy assignment
+        /*!
+        @brief copy assignment
+        @param[in,out] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
         const_iterator& operator=(const_iterator other) noexcept(
             std::is_nothrow_move_constructible<pointer>::value and
             std::is_nothrow_move_assignable<pointer>::value and
@@ -6574,7 +6715,10 @@ class basic_json
         }
 
       private:
-        /// set the iterator to the first value
+        /*!
+        @brief set the iterator to the first value
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         void set_begin() noexcept
         {
             assert(m_object != nullptr);
@@ -6583,14 +6727,12 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    assert(m_object->m_value.object != nullptr);
                     m_it.object_iterator = m_object->m_value.object->begin();
                     break;
                 }
 
                 case basic_json::value_t::array:
                 {
-                    assert(m_object->m_value.array != nullptr);
                     m_it.array_iterator = m_object->m_value.array->begin();
                     break;
                 }
@@ -6610,7 +6752,10 @@ class basic_json
             }
         }
 
-        /// set the iterator past the last value
+        /*!
+        @brief set the iterator past the last value
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         void set_end() noexcept
         {
             assert(m_object != nullptr);
@@ -6619,14 +6764,12 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    assert(m_object->m_value.object != nullptr);
                     m_it.object_iterator = m_object->m_value.object->end();
                     break;
                 }
 
                 case basic_json::value_t::array:
                 {
-                    assert(m_object->m_value.array != nullptr);
                     m_it.array_iterator = m_object->m_value.array->end();
                     break;
                 }
@@ -6640,7 +6783,10 @@ class basic_json
         }
 
       public:
-        /// return a reference to the value pointed to by the iterator
+        /*!
+        @brief return a reference to the value pointed to by the iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         reference operator*() const
         {
             assert(m_object != nullptr);
@@ -6649,14 +6795,12 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    assert(m_object->m_value.object);
                     assert(m_it.object_iterator != m_object->m_value.object->end());
                     return m_it.object_iterator->second;
                 }
 
                 case basic_json::value_t::array:
                 {
-                    assert(m_object->m_value.array);
                     assert(m_it.array_iterator != m_object->m_value.array->end());
                     return *m_it.array_iterator;
                 }
@@ -6680,7 +6824,10 @@ class basic_json
             }
         }
 
-        /// dereference the iterator
+        /*!
+        @brief dereference the iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         pointer operator->() const
         {
             assert(m_object != nullptr);
@@ -6689,14 +6836,12 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    assert(m_object->m_value.object);
                     assert(m_it.object_iterator != m_object->m_value.object->end());
                     return &(m_it.object_iterator->second);
                 }
 
                 case basic_json::value_t::array:
                 {
-                    assert(m_object->m_value.array);
                     assert(m_it.array_iterator != m_object->m_value.array->end());
                     return &*m_it.array_iterator;
                 }
@@ -6715,7 +6860,10 @@ class basic_json
             }
         }
 
-        /// post-increment (it++)
+        /*!
+        @brief post-increment (it++)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         const_iterator operator++(int)
         {
             auto result = *this;
@@ -6723,7 +6871,10 @@ class basic_json
             return result;
         }
 
-        /// pre-increment (++it)
+        /*!
+        @brief pre-increment (++it)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         const_iterator& operator++()
         {
             assert(m_object != nullptr);
@@ -6732,13 +6883,13 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    ++m_it.object_iterator;
+                    std::advance(m_it.object_iterator, 1);
                     break;
                 }
 
                 case basic_json::value_t::array:
                 {
-                    ++m_it.array_iterator;
+                    std::advance(m_it.array_iterator, 1);
                     break;
                 }
 
@@ -6752,7 +6903,10 @@ class basic_json
             return *this;
         }
 
-        /// post-decrement (it--)
+        /*!
+        @brief post-decrement (it--)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         const_iterator operator--(int)
         {
             auto result = *this;
@@ -6760,7 +6914,10 @@ class basic_json
             return result;
         }
 
-        /// pre-decrement (--it)
+        /*!
+        @brief pre-decrement (--it)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         const_iterator& operator--()
         {
             assert(m_object != nullptr);
@@ -6769,13 +6926,13 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    --m_it.object_iterator;
+                    std::advance(m_it.object_iterator, -1);
                     break;
                 }
 
                 case basic_json::value_t::array:
                 {
-                    --m_it.array_iterator;
+                    std::advance(m_it.array_iterator, -1);
                     break;
                 }
 
@@ -6789,7 +6946,10 @@ class basic_json
             return *this;
         }
 
-        /// comparison: equal
+        /*!
+        @brief  comparison: equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         bool operator==(const const_iterator& other) const
         {
             // if objects are not the same, the comparison is undefined
@@ -6819,13 +6979,19 @@ class basic_json
             }
         }
 
-        /// comparison: not equal
+        /*!
+        @brief  comparison: not equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         bool operator!=(const const_iterator& other) const
         {
             return not operator==(other);
         }
 
-        /// comparison: smaller
+        /*!
+        @brief  comparison: smaller
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         bool operator<(const const_iterator& other) const
         {
             // if objects are not the same, the comparison is undefined
@@ -6855,25 +7021,37 @@ class basic_json
             }
         }
 
-        /// comparison: less than or equal
+        /*!
+        @brief  comparison: less than or equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         bool operator<=(const const_iterator& other) const
         {
             return not other.operator < (*this);
         }
 
-        /// comparison: greater than
+        /*!
+        @brief  comparison: greater than
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         bool operator>(const const_iterator& other) const
         {
             return not operator<=(other);
         }
 
-        /// comparison: greater than or equal
+        /*!
+        @brief  comparison: greater than or equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         bool operator>=(const const_iterator& other) const
         {
             return not operator<(other);
         }
 
-        /// add to iterator
+        /*!
+        @brief  add to iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         const_iterator& operator+=(difference_type i)
         {
             assert(m_object != nullptr);
@@ -6887,7 +7065,7 @@ class basic_json
 
                 case basic_json::value_t::array:
                 {
-                    m_it.array_iterator += i;
+                    std::advance(m_it.array_iterator, i);
                     break;
                 }
 
@@ -6901,13 +7079,19 @@ class basic_json
             return *this;
         }
 
-        /// subtract from iterator
+        /*!
+        @brief  subtract from iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         const_iterator& operator-=(difference_type i)
         {
             return operator+=(-i);
         }
 
-        /// add to iterator
+        /*!
+        @brief  add to iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         const_iterator operator+(difference_type i)
         {
             auto result = *this;
@@ -6915,7 +7099,10 @@ class basic_json
             return result;
         }
 
-        /// subtract from iterator
+        /*!
+        @brief  subtract from iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         const_iterator operator-(difference_type i)
         {
             auto result = *this;
@@ -6923,7 +7110,10 @@ class basic_json
             return result;
         }
 
-        /// return difference
+        /*!
+        @brief  return difference
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         difference_type operator-(const const_iterator& other) const
         {
             assert(m_object != nullptr);
@@ -6947,7 +7137,10 @@ class basic_json
             }
         }
 
-        /// access to successor
+        /*!
+        @brief  access to successor
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         reference operator[](difference_type n) const
         {
             assert(m_object != nullptr);
@@ -6961,7 +7154,7 @@ class basic_json
 
                 case basic_json::value_t::array:
                 {
-                    return *(m_it.array_iterator + n);
+                    return *std::next(m_it.array_iterator, n);
                 }
 
                 case basic_json::value_t::null:
@@ -6983,7 +7176,10 @@ class basic_json
             }
         }
 
-        /// return the key of an object iterator
+        /*!
+        @brief  return the key of an object iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         typename object_t::key_type key() const
         {
             assert(m_object != nullptr);
@@ -6998,7 +7194,10 @@ class basic_json
             }
         }
 
-        /// return the value of an iterator
+        /*!
+        @brief  return the value of an iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
         reference value() const
         {
             return operator*();
@@ -7300,7 +7499,7 @@ class basic_json
         explicit lexer(const string_t& s) noexcept
             : m_stream(nullptr), m_buffer(s)
         {
-            m_content = reinterpret_cast<const lexer_char_t*>(s.c_str());
+            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
             assert(m_content != nullptr);
             m_start = m_cursor = m_content;
             m_limit = m_content + s.size();
@@ -7311,7 +7510,7 @@ class basic_json
             : m_stream(s), m_buffer()
         {
             assert(m_stream != nullptr);
-            getline(*m_stream, m_buffer);
+            std::getline(*m_stream, m_buffer);
             m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
             assert(m_content != nullptr);
             m_start = m_cursor = m_content;
@@ -7326,24 +7525,32 @@ class basic_json
         lexer operator=(const lexer&) = delete;
 
         /*!
-        @brief create a string from a Unicode code point
+        @brief create a string from one or two Unicode code points
+
+        There are two cases: (1) @a codepoint1 is in the Basic Multilingual
+        Plane (U+0000 through U+FFFF) and @a codepoint2 is 0, or (2)
+        @a codepoint1 and @a codepoint2 are a UTF-16 surrogate pair to
+        represent a code point above U+FFFF.
 
         @param[in] codepoint1  the code point (can be high surrogate)
         @param[in] codepoint2  the code point (can be low surrogate or 0)
 
-        @return string representation of the code point
+        @return string representation of the code point; the length of the
+        result string is between 1 and 4 characters.
 
         @throw std::out_of_range if code point is > 0x10ffff; example: `"code
         points above 0x10FFFF are invalid"`
         @throw std::invalid_argument if the low surrogate is invalid; example:
         `""missing or wrong low surrogate""`
 
+        @complexity Constant.
+
         @see <http://en.wikipedia.org/wiki/UTF-8#Sample_code>
         */
         static string_t to_unicode(const std::size_t codepoint1,
                                    const std::size_t codepoint2 = 0)
         {
-            // calculate the codepoint from the given code points
+            // calculate the code point from the given code points
             std::size_t codepoint = codepoint1;
 
             // check if codepoint1 is a high surrogate
@@ -7405,7 +7612,7 @@ class basic_json
         }
 
         /// return name of values of type token_type (only used for errors)
-        static std::string token_type_name(token_type t)
+        static std::string token_type_name(const token_type t)
         {
             switch (t)
             {
@@ -7454,769 +7661,798 @@ class basic_json
         function consists of a large block of code with `goto` jumps.
 
         @return the class of the next token read from the buffer
+
+        @complexity Linear in the length of the input.\n
+
+        Proposition: The loop below will always terminate for finite input.\n
+
+        Proof (by contradiction): Assume a finite input. To loop forever, the
+        loop must never hit code with a `break` statement. The only code
+        snippets without a `break` statement are the continue statements for
+        whitespace and byte-order-marks. To loop forever, the input must be an
+        infinite sequence of whitespace or byte-order-marks. This contradicts
+        the assumption of finite input, q.e.d.
         */
         token_type scan() noexcept
         {
-            // pointer for backtracking information
-            m_marker = nullptr;
+            while (true)
+            {
+                // pointer for backtracking information
+                m_marker = nullptr;
 
-            // remember the begin of the token
-            m_start = m_cursor;
-            assert(m_start != nullptr);
+                // remember the begin of the token
+                m_start = m_cursor;
+                assert(m_start != nullptr);
 
 
-            {
-                lexer_char_t yych;
-                unsigned int yyaccept = 0;
-                static const unsigned char yybm[] =
-                {
-                    0,   0,   0,   0,   0,   0,   0,   0,
-                    0,  32,  32,   0,   0,  32,   0,   0,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    160, 128,   0, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    192, 192, 192, 192, 192, 192, 192, 192,
-                    192, 192, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128,   0, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                    128, 128, 128, 128, 128, 128, 128, 128,
-                };
-                if ((m_limit - m_cursor) < 5)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yybm[0 + yych] & 32)
-                {
-                    goto basic_json_parser_6;
-                }
-                if (yych <= '\\')
-                {
-                    if (yych <= '-')
-                    {
-                        if (yych <= '"')
-                        {
-                            if (yych <= 0x00)
-                            {
-                                goto basic_json_parser_2;
-                            }
-                            if (yych <= '!')
-                            {
-                                goto basic_json_parser_4;
-                            }
-                            goto basic_json_parser_9;
-                        }
-                        else
-                        {
-                            if (yych <= '+')
-                            {
-                                goto basic_json_parser_4;
-                            }
-                            if (yych <= ',')
-                            {
-                                goto basic_json_parser_10;
-                            }
-                            goto basic_json_parser_12;
-                        }
+                {
+                    lexer_char_t yych;
+                    unsigned int yyaccept = 0;
+                    static const unsigned char yybm[] =
+                    {
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,  32,  32,   0,   0,  32,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        160, 128,   0, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        192, 192, 192, 192, 192, 192, 192, 192,
+                        192, 192, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128,   0, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                    };
+                    if ((m_limit - m_cursor) < 5)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
                     }
-                    else
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 32)
                     {
-                        if (yych <= '9')
-                        {
-                            if (yych <= '/')
-                            {
-                                goto basic_json_parser_4;
-                            }
-                            if (yych <= '0')
-                            {
-                                goto basic_json_parser_13;
-                            }
-                            goto basic_json_parser_15;
-                        }
-                        else
-                        {
-                            if (yych <= ':')
-                            {
-                                goto basic_json_parser_17;
-                            }
-                            if (yych == '[')
-                            {
-                                goto basic_json_parser_19;
-                            }
-                            goto basic_json_parser_4;
-                        }
+                        goto basic_json_parser_6;
                     }
-                }
-                else
-                {
-                    if (yych <= 't')
+                    if (yych <= '\\')
                     {
-                        if (yych <= 'f')
+                        if (yych <= '-')
                         {
-                            if (yych <= ']')
+                            if (yych <= '"')
                             {
-                                goto basic_json_parser_21;
+                                if (yych <= 0x00)
+                                {
+                                    goto basic_json_parser_2;
+                                }
+                                if (yych <= '!')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_9;
                             }
-                            if (yych <= 'e')
+                            else
                             {
-                                goto basic_json_parser_4;
+                                if (yych <= '+')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                if (yych <= ',')
+                                {
+                                    goto basic_json_parser_10;
+                                }
+                                goto basic_json_parser_12;
                             }
-                            goto basic_json_parser_23;
                         }
                         else
                         {
-                            if (yych == 'n')
+                            if (yych <= '9')
                             {
-                                goto basic_json_parser_24;
+                                if (yych <= '/')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                if (yych <= '0')
+                                {
+                                    goto basic_json_parser_13;
+                                }
+                                goto basic_json_parser_15;
                             }
-                            if (yych <= 's')
+                            else
                             {
+                                if (yych <= ':')
+                                {
+                                    goto basic_json_parser_17;
+                                }
+                                if (yych == '[')
+                                {
+                                    goto basic_json_parser_19;
+                                }
                                 goto basic_json_parser_4;
                             }
-                            goto basic_json_parser_25;
                         }
                     }
                     else
                     {
-                        if (yych <= '|')
+                        if (yych <= 't')
                         {
-                            if (yych == '{')
+                            if (yych <= 'f')
                             {
-                                goto basic_json_parser_26;
+                                if (yych <= ']')
+                                {
+                                    goto basic_json_parser_21;
+                                }
+                                if (yych <= 'e')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_23;
+                            }
+                            else
+                            {
+                                if (yych == 'n')
+                                {
+                                    goto basic_json_parser_24;
+                                }
+                                if (yych <= 's')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_25;
                             }
-                            goto basic_json_parser_4;
                         }
                         else
                         {
-                            if (yych <= '}')
+                            if (yych <= '|')
                             {
-                                goto basic_json_parser_28;
+                                if (yych == '{')
+                                {
+                                    goto basic_json_parser_26;
+                                }
+                                goto basic_json_parser_4;
                             }
-                            if (yych == 0xEF)
+                            else
                             {
-                                goto basic_json_parser_30;
+                                if (yych <= '}')
+                                {
+                                    goto basic_json_parser_28;
+                                }
+                                if (yych == 0xEF)
+                                {
+                                    goto basic_json_parser_30;
+                                }
+                                goto basic_json_parser_4;
                             }
-                            goto basic_json_parser_4;
                         }
                     }
-                }
 basic_json_parser_2:
-                ++m_cursor;
-                {
-                    return token_type::end_of_input;
-                }
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_of_input;
+                        break;
+                    }
 basic_json_parser_4:
-                ++m_cursor;
+                    ++m_cursor;
 basic_json_parser_5:
-                {
-                    return token_type::parse_error;
-                }
+                    {
+                        last_token_type = token_type::parse_error;
+                        break;
+                    }
 basic_json_parser_6:
-                ++m_cursor;
-                if (m_limit <= m_cursor)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yybm[0 + yych] & 32)
-                {
-                    goto basic_json_parser_6;
-                }
-                {
-                    return scan();
-                }
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 32)
+                    {
+                        goto basic_json_parser_6;
+                    }
+                    {
+                        continue;
+                    }
 basic_json_parser_9:
-                yyaccept = 0;
-                yych = *(m_marker = ++m_cursor);
-                if (yych <= 0x0F)
-                {
-                    goto basic_json_parser_5;
-                }
-                goto basic_json_parser_32;
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych <= 0x1F)
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    goto basic_json_parser_32;
 basic_json_parser_10:
-                ++m_cursor;
-                {
-                    return token_type::value_separator;
-                }
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::value_separator;
+                        break;
+                    }
 basic_json_parser_12:
-                yych = *++m_cursor;
-                if (yych <= '/')
-                {
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    if (yych <= '0')
+                    {
+                        goto basic_json_parser_13;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_15;
+                    }
                     goto basic_json_parser_5;
-                }
-                if (yych <= '0')
-                {
-                    goto basic_json_parser_13;
-                }
-                if (yych <= '9')
-                {
-                    goto basic_json_parser_15;
-                }
-                goto basic_json_parser_5;
 basic_json_parser_13:
-                yyaccept = 1;
-                yych = *(m_marker = ++m_cursor);
-                if (yych <= 'D')
-                {
-                    if (yych == '.')
+                    yyaccept = 1;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych <= 'D')
                     {
-                        goto basic_json_parser_37;
+                        if (yych == '.')
+                        {
+                            goto basic_json_parser_37;
+                        }
                     }
-                }
-                else
-                {
-                    if (yych <= 'E')
+                    else
                     {
-                        goto basic_json_parser_38;
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
                     }
-                    if (yych == 'e')
+basic_json_parser_14:
                     {
-                        goto basic_json_parser_38;
+                        last_token_type = token_type::value_number;
+                        break;
                     }
-                }
-basic_json_parser_14:
-                {
-                    return token_type::value_number;
-                }
 basic_json_parser_15:
-                yyaccept = 1;
-                m_marker = ++m_cursor;
-                if ((m_limit - m_cursor) < 3)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yybm[0 + yych] & 64)
-                {
-                    goto basic_json_parser_15;
-                }
-                if (yych <= 'D')
-                {
-                    if (yych == '.')
+                    yyaccept = 1;
+                    m_marker = ++m_cursor;
+                    if ((m_limit - m_cursor) < 3)
                     {
-                        goto basic_json_parser_37;
+                        yyfill();    // LCOV_EXCL_LINE;
                     }
-                    goto basic_json_parser_14;
-                }
-                else
-                {
-                    if (yych <= 'E')
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 64)
                     {
-                        goto basic_json_parser_38;
+                        goto basic_json_parser_15;
                     }
-                    if (yych == 'e')
+                    if (yych <= 'D')
+                    {
+                        if (yych == '.')
+                        {
+                            goto basic_json_parser_37;
+                        }
+                        goto basic_json_parser_14;
+                    }
+                    else
                     {
-                        goto basic_json_parser_38;
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        goto basic_json_parser_14;
                     }
-                    goto basic_json_parser_14;
-                }
 basic_json_parser_17:
-                ++m_cursor;
-                {
-                    return token_type::name_separator;
-                }
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::name_separator;
+                        break;
+                    }
 basic_json_parser_19:
-                ++m_cursor;
-                {
-                    return token_type::begin_array;
-                }
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::begin_array;
+                        break;
+                    }
 basic_json_parser_21:
-                ++m_cursor;
-                {
-                    return token_type::end_array;
-                }
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_array;
+                        break;
+                    }
 basic_json_parser_23:
-                yyaccept = 0;
-                yych = *(m_marker = ++m_cursor);
-                if (yych == 'a')
-                {
-                    goto basic_json_parser_39;
-                }
-                goto basic_json_parser_5;
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'a')
+                    {
+                        goto basic_json_parser_39;
+                    }
+                    goto basic_json_parser_5;
 basic_json_parser_24:
-                yyaccept = 0;
-                yych = *(m_marker = ++m_cursor);
-                if (yych == 'u')
-                {
-                    goto basic_json_parser_40;
-                }
-                goto basic_json_parser_5;
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'u')
+                    {
+                        goto basic_json_parser_40;
+                    }
+                    goto basic_json_parser_5;
 basic_json_parser_25:
-                yyaccept = 0;
-                yych = *(m_marker = ++m_cursor);
-                if (yych == 'r')
-                {
-                    goto basic_json_parser_41;
-                }
-                goto basic_json_parser_5;
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'r')
+                    {
+                        goto basic_json_parser_41;
+                    }
+                    goto basic_json_parser_5;
 basic_json_parser_26:
-                ++m_cursor;
-                {
-                    return token_type::begin_object;
-                }
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::begin_object;
+                        break;
+                    }
 basic_json_parser_28:
-                ++m_cursor;
-                {
-                    return token_type::end_object;
-                }
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_object;
+                        break;
+                    }
 basic_json_parser_30:
-                yyaccept = 0;
-                yych = *(m_marker = ++m_cursor);
-                if (yych == 0xBB)
-                {
-                    goto basic_json_parser_42;
-                }
-                goto basic_json_parser_5;
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 0xBB)
+                    {
+                        goto basic_json_parser_42;
+                    }
+                    goto basic_json_parser_5;
 basic_json_parser_31:
-                ++m_cursor;
-                if (m_limit <= m_cursor)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
 basic_json_parser_32:
-                if (yybm[0 + yych] & 128)
-                {
-                    goto basic_json_parser_31;
-                }
-                if (yych <= 0x0F)
-                {
-                    goto basic_json_parser_33;
-                }
-                if (yych <= '"')
-                {
-                    goto basic_json_parser_34;
-                }
-                goto basic_json_parser_36;
+                    if (yybm[0 + yych] & 128)
+                    {
+                        goto basic_json_parser_31;
+                    }
+                    if (yych <= 0x1F)
+                    {
+                        goto basic_json_parser_33;
+                    }
+                    if (yych <= '"')
+                    {
+                        goto basic_json_parser_34;
+                    }
+                    goto basic_json_parser_36;
 basic_json_parser_33:
-                m_cursor = m_marker;
-                if (yyaccept == 0)
-                {
-                    goto basic_json_parser_5;
-                }
-                else
-                {
-                    goto basic_json_parser_14;
-                }
+                    m_cursor = m_marker;
+                    if (yyaccept == 0)
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    else
+                    {
+                        goto basic_json_parser_14;
+                    }
 basic_json_parser_34:
-                ++m_cursor;
-                {
-                    return token_type::value_string;
-                }
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::value_string;
+                        break;
+                    }
 basic_json_parser_36:
-                ++m_cursor;
-                if (m_limit <= m_cursor)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yych <= 'e')
-                {
-                    if (yych <= '/')
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 'e')
                     {
-                        if (yych == '"')
+                        if (yych <= '/')
                         {
+                            if (yych == '"')
+                            {
+                                goto basic_json_parser_31;
+                            }
+                            if (yych <= '.')
+                            {
+                                goto basic_json_parser_33;
+                            }
                             goto basic_json_parser_31;
                         }
-                        if (yych <= '.')
+                        else
                         {
-                            goto basic_json_parser_33;
+                            if (yych <= '\\')
+                            {
+                                if (yych <= '[')
+                                {
+                                    goto basic_json_parser_33;
+                                }
+                                goto basic_json_parser_31;
+                            }
+                            else
+                            {
+                                if (yych == 'b')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                goto basic_json_parser_33;
+                            }
                         }
-                        goto basic_json_parser_31;
                     }
                     else
                     {
-                        if (yych <= '\\')
+                        if (yych <= 'q')
                         {
-                            if (yych <= '[')
+                            if (yych <= 'f')
                             {
-                                goto basic_json_parser_33;
+                                goto basic_json_parser_31;
                             }
-                            goto basic_json_parser_31;
+                            if (yych == 'n')
+                            {
+                                goto basic_json_parser_31;
+                            }
+                            goto basic_json_parser_33;
                         }
                         else
                         {
-                            if (yych == 'b')
+                            if (yych <= 's')
                             {
-                                goto basic_json_parser_31;
+                                if (yych <= 'r')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                goto basic_json_parser_33;
+                            }
+                            else
+                            {
+                                if (yych <= 't')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                if (yych <= 'u')
+                                {
+                                    goto basic_json_parser_43;
+                                }
+                                goto basic_json_parser_33;
                             }
+                        }
+                    }
+basic_json_parser_37:
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_33;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_44;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_38:
+                    yych = *++m_cursor;
+                    if (yych <= ',')
+                    {
+                        if (yych == '+')
+                        {
+                            goto basic_json_parser_46;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= '-')
+                        {
+                            goto basic_json_parser_46;
+                        }
+                        if (yych <= '/')
+                        {
                             goto basic_json_parser_33;
                         }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_47;
+                        }
+                        goto basic_json_parser_33;
                     }
-                }
-                else
-                {
-                    if (yych <= 'q')
+basic_json_parser_39:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
                     {
-                        if (yych <= 'f')
+                        goto basic_json_parser_49;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_40:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
+                    {
+                        goto basic_json_parser_50;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_41:
+                    yych = *++m_cursor;
+                    if (yych == 'u')
+                    {
+                        goto basic_json_parser_51;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_42:
+                    yych = *++m_cursor;
+                    if (yych == 0xBF)
+                    {
+                        goto basic_json_parser_52;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_43:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
                         {
-                            goto basic_json_parser_31;
+                            goto basic_json_parser_33;
                         }
-                        if (yych == 'n')
+                        if (yych <= '9')
                         {
-                            goto basic_json_parser_31;
+                            goto basic_json_parser_54;
                         }
                         goto basic_json_parser_33;
                     }
                     else
                     {
-                        if (yych <= 's')
+                        if (yych <= 'F')
                         {
-                            if (yych <= 'r')
-                            {
-                                goto basic_json_parser_31;
-                            }
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_54;
                         }
-                        else
+                        if (yych <= '`')
                         {
-                            if (yych <= 't')
-                            {
-                                goto basic_json_parser_31;
-                            }
-                            if (yych <= 'u')
-                            {
-                                goto basic_json_parser_43;
-                            }
                             goto basic_json_parser_33;
                         }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_54;
+                        }
+                        goto basic_json_parser_33;
                     }
-                }
-basic_json_parser_37:
-                yych = *++m_cursor;
-                if (yych <= '/')
-                {
-                    goto basic_json_parser_33;
-                }
-                if (yych <= '9')
-                {
-                    goto basic_json_parser_44;
-                }
-                goto basic_json_parser_33;
-basic_json_parser_38:
-                yych = *++m_cursor;
-                if (yych <= ',')
-                {
-                    if (yych == '+')
-                    {
-                        goto basic_json_parser_46;
-                    }
-                    goto basic_json_parser_33;
-                }
-                else
-                {
-                    if (yych <= '-')
+basic_json_parser_44:
+                    yyaccept = 1;
+                    m_marker = ++m_cursor;
+                    if ((m_limit - m_cursor) < 3)
                     {
-                        goto basic_json_parser_46;
+                        yyfill();    // LCOV_EXCL_LINE;
                     }
-                    if (yych <= '/')
+                    yych = *m_cursor;
+                    if (yych <= 'D')
                     {
-                        goto basic_json_parser_33;
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_14;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_44;
+                        }
+                        goto basic_json_parser_14;
                     }
-                    if (yych <= '9')
+                    else
                     {
-                        goto basic_json_parser_47;
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        goto basic_json_parser_14;
                     }
-                    goto basic_json_parser_33;
-                }
-basic_json_parser_39:
-                yych = *++m_cursor;
-                if (yych == 'l')
-                {
-                    goto basic_json_parser_49;
-                }
-                goto basic_json_parser_33;
-basic_json_parser_40:
-                yych = *++m_cursor;
-                if (yych == 'l')
-                {
-                    goto basic_json_parser_50;
-                }
-                goto basic_json_parser_33;
-basic_json_parser_41:
-                yych = *++m_cursor;
-                if (yych == 'u')
-                {
-                    goto basic_json_parser_51;
-                }
-                goto basic_json_parser_33;
-basic_json_parser_42:
-                yych = *++m_cursor;
-                if (yych == 0xBF)
-                {
-                    goto basic_json_parser_52;
-                }
-                goto basic_json_parser_33;
-basic_json_parser_43:
-                ++m_cursor;
-                if (m_limit <= m_cursor)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yych <= '@')
-                {
+basic_json_parser_46:
+                    yych = *++m_cursor;
                     if (yych <= '/')
                     {
                         goto basic_json_parser_33;
                     }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_54;
-                    }
-                    goto basic_json_parser_33;
-                }
-                else
-                {
-                    if (yych <= 'F')
-                    {
-                        goto basic_json_parser_54;
-                    }
-                    if (yych <= '`')
+                    if (yych >= ':')
                     {
                         goto basic_json_parser_33;
                     }
-                    if (yych <= 'f')
+basic_json_parser_47:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
                     {
-                        goto basic_json_parser_54;
+                        yyfill();    // LCOV_EXCL_LINE;
                     }
-                    goto basic_json_parser_33;
-                }
-basic_json_parser_44:
-                yyaccept = 1;
-                m_marker = ++m_cursor;
-                if ((m_limit - m_cursor) < 3)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yych <= 'D')
-                {
+                    yych = *m_cursor;
                     if (yych <= '/')
                     {
                         goto basic_json_parser_14;
                     }
                     if (yych <= '9')
                     {
-                        goto basic_json_parser_44;
+                        goto basic_json_parser_47;
                     }
                     goto basic_json_parser_14;
-                }
-                else
-                {
-                    if (yych <= 'E')
+basic_json_parser_49:
+                    yych = *++m_cursor;
+                    if (yych == 's')
                     {
-                        goto basic_json_parser_38;
+                        goto basic_json_parser_55;
                     }
-                    if (yych == 'e')
+                    goto basic_json_parser_33;
+basic_json_parser_50:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
                     {
-                        goto basic_json_parser_38;
+                        goto basic_json_parser_56;
                     }
-                    goto basic_json_parser_14;
-                }
-basic_json_parser_46:
-                yych = *++m_cursor;
-                if (yych <= '/')
-                {
-                    goto basic_json_parser_33;
-                }
-                if (yych >= ':')
-                {
                     goto basic_json_parser_33;
-                }
-basic_json_parser_47:
-                ++m_cursor;
-                if (m_limit <= m_cursor)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yych <= '/')
-                {
-                    goto basic_json_parser_14;
-                }
-                if (yych <= '9')
-                {
-                    goto basic_json_parser_47;
-                }
-                goto basic_json_parser_14;
-basic_json_parser_49:
-                yych = *++m_cursor;
-                if (yych == 's')
-                {
-                    goto basic_json_parser_55;
-                }
-                goto basic_json_parser_33;
-basic_json_parser_50:
-                yych = *++m_cursor;
-                if (yych == 'l')
-                {
-                    goto basic_json_parser_56;
-                }
-                goto basic_json_parser_33;
 basic_json_parser_51:
-                yych = *++m_cursor;
-                if (yych == 'e')
-                {
-                    goto basic_json_parser_58;
-                }
-                goto basic_json_parser_33;
+                    yych = *++m_cursor;
+                    if (yych == 'e')
+                    {
+                        goto basic_json_parser_58;
+                    }
+                    goto basic_json_parser_33;
 basic_json_parser_52:
-                ++m_cursor;
-                {
-                    return scan();
-                }
-basic_json_parser_54:
-                ++m_cursor;
-                if (m_limit <= m_cursor)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yych <= '@')
-                {
-                    if (yych <= '/')
+                    ++m_cursor;
                     {
-                        goto basic_json_parser_33;
+                        continue;
                     }
-                    if (yych <= '9')
+basic_json_parser_54:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
                     {
-                        goto basic_json_parser_60;
+                        yyfill();    // LCOV_EXCL_LINE;
                     }
-                    goto basic_json_parser_33;
-                }
-                else
-                {
-                    if (yych <= 'F')
+                    yych = *m_cursor;
+                    if (yych <= '@')
                     {
-                        goto basic_json_parser_60;
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_60;
+                        }
+                        goto basic_json_parser_33;
                     }
-                    if (yych <= '`')
+                    else
                     {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_60;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_60;
+                        }
                         goto basic_json_parser_33;
                     }
-                    if (yych <= 'f')
+basic_json_parser_55:
+                    yych = *++m_cursor;
+                    if (yych == 'e')
                     {
-                        goto basic_json_parser_60;
+                        goto basic_json_parser_61;
                     }
                     goto basic_json_parser_33;
-                }
-basic_json_parser_55:
-                yych = *++m_cursor;
-                if (yych == 'e')
-                {
-                    goto basic_json_parser_61;
-                }
-                goto basic_json_parser_33;
 basic_json_parser_56:
-                ++m_cursor;
-                {
-                    return token_type::literal_null;
-                }
-basic_json_parser_58:
-                ++m_cursor;
-                {
-                    return token_type::literal_true;
-                }
-basic_json_parser_60:
-                ++m_cursor;
-                if (m_limit <= m_cursor)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yych <= '@')
-                {
-                    if (yych <= '/')
+                    ++m_cursor;
                     {
-                        goto basic_json_parser_33;
+                        last_token_type = token_type::literal_null;
+                        break;
                     }
-                    if (yych <= '9')
+basic_json_parser_58:
+                    ++m_cursor;
                     {
-                        goto basic_json_parser_63;
+                        last_token_type = token_type::literal_true;
+                        break;
                     }
-                    goto basic_json_parser_33;
-                }
-                else
-                {
-                    if (yych <= 'F')
+basic_json_parser_60:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
                     {
-                        goto basic_json_parser_63;
+                        yyfill();    // LCOV_EXCL_LINE;
                     }
-                    if (yych <= '`')
+                    yych = *m_cursor;
+                    if (yych <= '@')
                     {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_63;
+                        }
                         goto basic_json_parser_33;
                     }
-                    if (yych <= 'f')
-                    {
-                        goto basic_json_parser_63;
-                    }
-                    goto basic_json_parser_33;
-                }
-basic_json_parser_61:
-                ++m_cursor;
-                {
-                    return token_type::literal_false;
-                }
-basic_json_parser_63:
-                ++m_cursor;
-                if (m_limit <= m_cursor)
-                {
-                    yyfill();    // LCOV_EXCL_LINE;
-                }
-                yych = *m_cursor;
-                if (yych <= '@')
-                {
-                    if (yych <= '/')
+                    else
                     {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_63;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_63;
+                        }
                         goto basic_json_parser_33;
                     }
-                    if (yych <= '9')
+basic_json_parser_61:
+                    ++m_cursor;
                     {
-                        goto basic_json_parser_31;
+                        last_token_type = token_type::literal_false;
+                        break;
                     }
-                    goto basic_json_parser_33;
-                }
-                else
-                {
-                    if (yych <= 'F')
+basic_json_parser_63:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
                     {
-                        goto basic_json_parser_31;
+                        yyfill();    // LCOV_EXCL_LINE;
                     }
-                    if (yych <= '`')
+                    yych = *m_cursor;
+                    if (yych <= '@')
                     {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_31;
+                        }
                         goto basic_json_parser_33;
                     }
-                    if (yych <= 'f')
+                    else
                     {
-                        goto basic_json_parser_31;
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_31;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_31;
+                        }
+                        goto basic_json_parser_33;
                     }
-                    goto basic_json_parser_33;
                 }
+
             }
 
+            return last_token_type;
         }
 
         /// append data from the stream to the internal buffer
@@ -8246,7 +8482,7 @@ basic_json_parser_63:
         }
 
         /// return string representation of last read token
-        string_t get_token() const
+        string_t get_token_string() const
         {
             assert(m_start != nullptr);
             return string_t(reinterpret_cast<typename string_t::const_pointer>(m_start),
@@ -8271,12 +8507,49 @@ basic_json_parser_63:
            of the construction of the values.
         2. Unescaped characters are copied as is.
 
+        @pre `m_cursor - m_start >= 2`, meaning the length of the last token
+        is at least 2 bytes which is trivially true for any string (which
+        consists of at least two quotes).
+
+            " c1 c2 c3 ... "
+            ^                ^
+            m_start          m_cursor
+
+        @complexity Linear in the length of the string.\n
+
+        Lemma: The loop body will always terminate.\n
+
+        Proof (by contradiction): Assume the loop body does not terminate. As
+        the loop body does not contain another loop, one of the called
+        functions must never return. The called functions are `std::strtoul`
+        and to_unicode. Neither function can loop forever, so the loop body
+        will never loop forever which contradicts the assumption that the loop
+        body does not terminate, q.e.d.\n
+
+        Lemma: The loop condition for the for loop is eventually false.\n
+
+        Proof (by contradiction): Assume the loop does not terminate. Due to
+        the above lemma, this can only be due to a tautological loop
+        condition; that is, the loop condition i < m_cursor - 1 must always be
+        true. Let x be the change of i for any loop iteration. Then
+        m_start + 1 + x < m_cursor - 1 must hold to loop indefinitely. This
+        can be rephrased to m_cursor - m_start - 2 > x. With the
+        precondition, we x <= 0, meaning that the loop condition holds
+        indefinitly if i is always decreased. However, observe that the value
+        of i is strictly increasing with each iteration, as it is incremented
+        by 1 in the iteration expression and never decremented inside the loop
+        body. Hence, the loop condition will eventually be false which
+        contradicts the assumption that the loop condition is a tautology,
+        q.e.d.
+
         @return string value of current token without opening and closing
         quotes
         @throw std::out_of_range if to_unicode fails
         */
         string_t get_string() const
         {
+            assert(m_cursor - m_start >= 2);
+
             string_t result;
             result.reserve(static_cast<size_t>(m_cursor - m_start - 2));
 
@@ -8392,11 +8665,6 @@ basic_json_parser_63:
         the number
 
         @return the floating point number
-
-        @bug This function uses `std::strtof`, `std::strtod`, or `std::strtold`
-        which use the current C locale to determine which character is used as
-        decimal point character. This may yield to parse errors if the locale
-        does not used `.`.
         */
         long double str_to_float_t(long double* /* type */, char** endptr) const
         {
@@ -8457,18 +8725,12 @@ basic_json_parser_63:
         number_integer_t or @ref number_unsigned_t then it sets the result
         parameter accordingly.
 
-        The 'floating point representation' includes the number of significant
-        figures after the radix point, whether the number is in exponential or
-        decimal form, the capitalization of the exponent marker, and if the
-        optional '+' is present in the exponent. This information is necessary
-        to perform accurate round trips of floating point numbers.
-
         If the number is a floating point number the number is then parsed
         using @a std:strtod (or @a std:strtof or @a std::strtold).
 
         @param[out] result  @ref basic_json object to receive the number, or
-          NAN if the conversion read past the current token. The latter case
-          needs to be treated by the caller function.
+        NAN if the conversion read past the current token. The latter case
+        needs to be treated by the caller function.
         */
         void get_number(basic_json& result) const
         {
@@ -8476,15 +8738,6 @@ basic_json_parser_63:
 
             const lexer::lexer_char_t* curptr = m_start;
 
-            // remember this number was parsed (for later serialization)
-            result.m_type.bits.parsed = true;
-
-            // 'found_radix_point' will be set to 0xFF upon finding a radix
-            // point and later used to mask in/out the precision depending
-            // whether a radix is found i.e. 'precision &= found_radix_point'
-            uint8_t found_radix_point = 0;
-            uint8_t precision = 0;
-
             // accumulate the integer conversion result (unsigned for now)
             number_unsigned_t value = 0;
 
@@ -8517,22 +8770,11 @@ basic_json_parser_63:
                     {
                         // don't count '.' but change to float
                         type = value_t::number_float;
-
-                        // reset precision count
-                        precision = 0;
-                        found_radix_point = 0xFF;
                         continue;
                     }
                     // assume exponent (if not then will fail parse): change to
                     // float, stop counting and record exponent details
                     type = value_t::number_float;
-                    result.m_type.bits.has_exp = true;
-
-                    // exponent capitalization
-                    result.m_type.bits.exp_cap = (*curptr == 'E');
-
-                    // exponent '+' sign
-                    result.m_type.bits.exp_plus = (*(++curptr) == '+');
                     break;
                 }
 
@@ -8540,7 +8782,7 @@ basic_json_parser_63:
                 if (type != value_t::number_float)
                 {
                     // multiply last value by ten and add the new digit
-                    auto temp = value * 10 + *curptr - 0x30;
+                    auto temp = value * 10 + *curptr - '0';
 
                     // test for overflow
                     if (temp < value || temp > max)
@@ -8554,13 +8796,8 @@ basic_json_parser_63:
                         value = temp;
                     }
                 }
-                ++precision;
             }
 
-            // If no radix point was found then precision would now be set to
-            // the number of digits, which is wrong - clear it.
-            result.m_type.bits.precision = precision & found_radix_point;
-
             // save the value (if not a float)
             if (type == value_t::number_unsigned)
             {
@@ -8595,6 +8832,8 @@ basic_json_parser_63:
         const lexer_char_t* m_cursor = nullptr;
         /// pointer to the end of the buffer
         const lexer_char_t* m_limit = nullptr;
+        /// the last token type
+        token_type last_token_type = token_type::end_of_input;
     };
 
     /*!
@@ -8606,7 +8845,7 @@ basic_json_parser_63:
     {
       public:
         /// constructor for strings
-        parser(const string_t& s, parser_callback_t cb = nullptr) noexcept
+        parser(const string_t& s, const parser_callback_t cb = nullptr) noexcept
             : callback(cb), m_lexer(s)
         {
             // read first token
@@ -8614,7 +8853,7 @@ basic_json_parser_63:
         }
 
         /// a parser reading from an input stream
-        parser(std::istream& _is, parser_callback_t cb = nullptr) noexcept
+        parser(std::istream& _is, const parser_callback_t cb = nullptr) noexcept
             : callback(cb), m_lexer(&_is)
         {
             // read first token
@@ -8625,12 +8864,13 @@ basic_json_parser_63:
         basic_json parse()
         {
             basic_json result = parse_internal(true);
+            result.assert_invariant();
 
             expect(lexer::token_type::end_of_input);
 
             // return parser result and replace it with null in case the
             // top-level value was discarded by the callback function
-            return result.is_discarded() ? basic_json() : result;
+            return result.is_discarded() ? basic_json() : std::move(result);
         }
 
       private:
@@ -8647,7 +8887,7 @@ basic_json_parser_63:
                     {
                         // explicitly set result to object to cope with {}
                         result.m_type = value_t::object;
-                        result.m_value = json_value(value_t::object);
+                        result.m_value = value_t::object;
                     }
 
                     // read next token
@@ -8725,7 +8965,7 @@ basic_json_parser_63:
                     {
                         // explicitly set result to object to cope with []
                         result.m_type = value_t::array;
-                        result.m_value = json_value(value_t::array);
+                        result.m_value = value_t::array;
                     }
 
                     // read next token
@@ -8838,7 +9078,8 @@ basic_json_parser_63:
             if (t != last_token)
             {
                 std::string error_msg = "parse error - unexpected ";
-                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token() + "'") :
+                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
+                              "'") :
                               lexer::token_type_name(last_token));
                 error_msg += "; expected " + lexer::token_type_name(t);
                 throw std::invalid_argument(error_msg);
@@ -8850,7 +9091,8 @@ basic_json_parser_63:
             if (t == last_token)
             {
                 std::string error_msg = "parse error - unexpected ";
-                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token() + "'") :
+                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
+                              "'") :
                               lexer::token_type_name(last_token));
                 throw std::invalid_argument(error_msg);
             }
@@ -8860,7 +9102,7 @@ basic_json_parser_63:
         /// current level of recursion
         int depth = 0;
         /// callback function
-        parser_callback_t callback;
+        const parser_callback_t callback = nullptr;
         /// the type of the last read token
         typename lexer::token_type last_token = lexer::token_type::uninitialized;
         /// the lexer
@@ -8928,14 +9170,12 @@ basic_json_parser_63:
         */
         std::string to_string() const noexcept
         {
-            std::string result;
-
-            for (const auto& reference_token : reference_tokens)
+            return std::accumulate(reference_tokens.begin(),
+                                   reference_tokens.end(), std::string{},
+                                   [](const std::string & a, const std::string & b)
             {
-                result += "/" + escape(reference_token);
-            }
-
-            return result;
+                return a + "/" + escape(b);
+            });
         }
 
         /// @copydoc to_string()
@@ -8978,6 +9218,8 @@ basic_json_parser_63:
 
         /*!
         @brief create and return a reference to the pointed to value
+
+        @complexity Linear in the number of reference tokens.
         */
         reference get_and_create(reference j) const
         {
@@ -9299,7 +9541,7 @@ basic_json_parser_63:
 
         @param[in,out] s  the string to manipulate
         @param[in]     f  the substring to replace with @a t
-        @param[out]    t  the string to replace @a f
+        @param[in]     t  the string to replace @a f
 
         @return The string @a s where all occurrences of @a f are replaced
                 with @a t.
@@ -10002,9 +10244,12 @@ basic_json_parser_63:
                     // in a second pass, traverse the remaining elements
 
                     // remove my remaining elements
+                    const auto end_index = static_cast<difference_type>(result.size());
                     while (i < source.size())
                     {
-                        result.push_back(object(
+                        // add operations in reverse order to avoid invalid
+                        // indices
+                        result.insert(result.begin() + end_index, object(
                         {
                             {"op", "remove"},
                             {"path", path + "/" + std::to_string(i)}
@@ -10152,7 +10397,7 @@ struct hash<nlohmann::json>
 @brief user-defined string literal for JSON values
 
 This operator implements a user-defined string literal for JSON objects. It
-can be used by adding \p "_json" to a string literal and returns a JSON object
+can be used by adding `"_json"` to a string literal and returns a JSON object
 if no parse error occurred.
 
 @param[in] s  a string representation of a JSON object
@@ -10168,6 +10413,13 @@ inline nlohmann::json operator "" _json(const char* s, std::size_t)
 /*!
 @brief user-defined string literal for JSON pointer
 
+This operator implements a user-defined string literal for JSON Pointers. It
+can be used by adding `"_json"` to a string literal and returns a JSON pointer
+object if no parse error occurred.
+
+@param[in] s  a string representation of a JSON Pointer
+@return a JSON pointer object
+
 @since version 2.0.0
 */
 inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t)
-- 
cgit v1.2.3


From c30f74987ff9027e3f7be3a9f400134c17d555e6 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Fri, 12 Aug 2016 11:30:27 -0700
Subject: Starting refactor of controller...

---
 controller/SqliteNetworkController.cpp |   672 +-
 controller/SqliteNetworkController.hpp |    74 +-
 controller/schema.sql                  |    24 +-
 ext/json/LICENSE.MIT                   |    22 -
 ext/json/README.md                     |   511 --
 ext/json/json.hpp                      | 10435 -------------------------------
 ext/offbase/README.md                  |    59 +
 ext/offbase/json/LICENSE.MIT           |    22 +
 ext/offbase/json/README.md             |   511 ++
 ext/offbase/json/json.hpp              | 10435 +++++++++++++++++++++++++++++++
 ext/offbase/offbase.hpp                |   393 ++
 11 files changed, 11552 insertions(+), 11606 deletions(-)
 delete mode 100644 ext/json/LICENSE.MIT
 delete mode 100644 ext/json/README.md
 delete mode 100644 ext/json/json.hpp
 create mode 100644 ext/offbase/README.md
 create mode 100644 ext/offbase/json/LICENSE.MIT
 create mode 100644 ext/offbase/json/README.md
 create mode 100644 ext/offbase/json/json.hpp
 create mode 100644 ext/offbase/offbase.hpp

(limited to 'ext/json/json.hpp')

diff --git a/controller/SqliteNetworkController.cpp b/controller/SqliteNetworkController.cpp
index 81017897..56bddbc3 100644
--- a/controller/SqliteNetworkController.cpp
+++ b/controller/SqliteNetworkController.cpp
@@ -37,16 +37,11 @@
 #include <utility>
 #include <stdexcept>
 #include <set>
+#include <map>
 
 #include "../include/ZeroTierOne.h"
 #include "../node/Constants.hpp"
 
-#ifdef ZT_USE_SYSTEM_JSON_PARSER
-#include <json-parser/json.h>
-#else
-#include "../ext/json-parser/json.h"
-#endif
-
 #include "SqliteNetworkController.hpp"
 
 #include "../node/Node.hpp"
@@ -60,17 +55,17 @@
 
 #include "../osdep/OSUtils.hpp"
 
-// Include ZT_NETCONF_SCHEMA_SQL constant to init database
-#include "schema.sql.c"
+// offbase includes and builds upon nlohmann::json
+using json = nlohmann::json;
 
 // Stored in database as schemaVersion key in Config.
 // If not present, database is assumed to be empty and at the current schema version
 // and this key/value is added automatically.
-#define ZT_NETCONF_SQLITE_SCHEMA_VERSION 5
-#define ZT_NETCONF_SQLITE_SCHEMA_VERSION_STR "5"
+//#define ZT_NETCONF_SQLITE_SCHEMA_VERSION 5
+//#define ZT_NETCONF_SQLITE_SCHEMA_VERSION_STR "5"
 
 // API version reported via JSON control plane
-#define ZT_NETCONF_CONTROLLER_API_VERSION 2
+#define ZT_NETCONF_CONTROLLER_API_VERSION 3
 
 // Number of requests to remember in member history
 #define ZT_NETCONF_DB_MEMBER_HISTORY_LENGTH 8
@@ -79,155 +74,19 @@
 #define ZT_NETCONF_MIN_REQUEST_PERIOD 1000
 
 // Delay between backups in milliseconds
-#define ZT_NETCONF_BACKUP_PERIOD 300000
+//#define ZT_NETCONF_BACKUP_PERIOD 300000
 
 // Nodes are considered active if they've queried in less than this long
 #define ZT_NETCONF_NODE_ACTIVE_THRESHOLD ((ZT_NETWORK_AUTOCONF_DELAY * 2) + 5000)
 
-// Flags for Network 'flags' field in table
-#define ZT_DB_NETWORK_FLAG_ZT_MANAGED_V4_AUTO_ASSIGN 1
-#define ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_RFC4193 2
-#define ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_6PLANE 4
-#define ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_AUTO_ASSIGN 8
-
-// Flags with all V6 managed mode flags flipped off -- for masking in update operation and in string form for SQL building
-#define ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_MASK_S "268435441"
-
-// Uncomment to trace Sqlite for debugging
-//#define ZT_NETCONF_SQLITE_TRACE 1
-
 namespace ZeroTier {
 
-namespace {
-
-static std::string _jsonEscape(const char *s)
-{
-	if (!s)
-		return std::string();
-	std::string buf;
-	for(const char *p=s;(*p);++p) {
-		switch(*p) {
-			case '\t': buf.append("\\t");  break;
-			case '\b': buf.append("\\b");  break;
-			case '\r': buf.append("\\r");  break;
-			case '\n': buf.append("\\n");  break;
-			case '\f': buf.append("\\f");  break;
-			case '"':  buf.append("\\\""); break;
-			case '\\': buf.append("\\\\"); break;
-			case '/':  buf.append("\\/");  break;
-			default:   buf.push_back(*p);  break;
-		}
-	}
-	return buf;
-}
-static std::string _jsonEscape(const std::string &s) { return _jsonEscape(s.c_str()); }
-
-// Converts an InetAddress to a blob and an int for storage in database
-static void _ipToBlob(const InetAddress &a,char *ipBlob,int &ipVersion) /* blob[16] */
-{
-	switch(a.ss_family) {
-		case AF_INET:
-			memset(ipBlob,0,12);
-			memcpy(ipBlob + 12,a.rawIpData(),4);
-			ipVersion = 4;
-			break;
-		case AF_INET6:
-			memcpy(ipBlob,a.rawIpData(),16);
-			ipVersion = 6;
-			break;
-	}
-}
-
-// Member.recentHistory is stored in a BLOB as an array of strings containing JSON objects.
-// This is kind of hacky but efficient and quick to parse and send to the client.
-class MemberRecentHistory : public std::list<std::string>
-{
-public:
-	inline std::string toBlob() const
-	{
-		std::string b;
-		for(const_iterator i(begin());i!=end();++i) {
-			b.append(*i);
-			b.push_back((char)0);
-		}
-		return b;
-	}
-
-	inline void fromBlob(const char *blob,unsigned int len)
-	{
-		for(unsigned int i=0,k=0;i<len;++i) {
-			if (!blob[i]) {
-				push_back(std::string(blob + k,i - k));
-				k = i + 1;
-			}
-		}
-	}
-};
-
-struct MemberRecord
-{
-	sqlite3_int64 rowid;
-	char nodeId[16];
-	bool authorized;
-	bool activeBridge;
-	uint64_t lastRequestTime;
-	MemberRecentHistory recentHistory;
-
-	MemberRecord() :
-		rowid(0),
-		authorized(false),
-		activeBridge(false),
-		lastRequestTime(0)
-	{
-		nodeId[0] = (char)0;
-	}
-};
-
-struct NetworkRecord
-{
-	char id[24];
-	const char *name;
-	int flags;
-	bool isPrivate;
-	bool enableBroadcast;
-	bool allowPassiveBridging;
-	int multicastLimit;
-	uint64_t creationTime;
-	uint64_t revision;
-	uint64_t memberRevisionCounter;
-
-	NetworkRecord() :
-		name((const char *)0),
-		flags(0),
-		isPrivate(true),
-		enableBroadcast(false),
-		allowPassiveBridging(false),
-		multicastLimit(0),
-		creationTime(0),
-		revision(0),
-		memberRevisionCounter(0)
-	{
-		id[0] = (char)0;
-	}
-};
-
-#ifdef ZT_NETCONF_SQLITE_TRACE
-static void sqliteTraceFunc(void *ptr,const char *s)
-{
-	fprintf(stderr,"SQLITE: %s\n",s);
-}
-#endif
-
-} // anonymous namespace
-
 SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,const char *circuitTestPath) :
 	_node(node),
-	_backupThreadRun(true),
-	_backupNeeded(true),
-	_dbPath(dbPath),
-	_circuitTestPath(circuitTestPath),
-	_db((sqlite3 *)0)
+	_db(dbPath),
+	_dbCommitThreadRun(true)
 {
+	/*
 	if (sqlite3_open_v2(dbPath,&_db,SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE,(const char *)0) != SQLITE_OK)
 		throw std::runtime_error("SqliteNetworkController cannot open database file");
 	sqlite3_busy_timeout(_db,10000);
@@ -337,11 +196,12 @@ SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,c
 		if (schemaVersion < 5) {
 			// Upgrade old rough draft Rule table to new release format
 			if (sqlite3_exec(_db,
+					"DROP TABLE Relay;\n"
 					"DROP INDEX Rule_networkId_ruleNo;\n"
 					"ALTER TABLE \"Rule\" RENAME TO RuleOld;\n"
 					"CREATE TABLE Rule (\n"
 					"  networkId char(16) NOT NULL REFERENCES Network(id) ON DELETE CASCADE,\n"
-					"  policyId varchar(32),\n"
+					"  capId integer,\n"
 					"  ruleNo integer NOT NULL,\n"
 					"  ruleType integer NOT NULL DEFAULT(0),\n"
 					"  \"addr\" blob(16),\n"
@@ -353,8 +213,16 @@ SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,c
 					"INSERT INTO \"Rule\" SELECT networkId,(ruleNo*2) AS ruleNo,37 AS \"ruleType\",etherType AS \"int1\" FROM RuleOld WHERE RuleOld.etherType IS NOT NULL AND RuleOld.etherType > 0;\n"
 					"INSERT INTO \"Rule\" SELECT networkId,((ruleNo*2)+1) AS ruleNo,1 AS \"ruleType\" FROM RuleOld;\n"
 					"DROP TABLE RuleOld;\n"
-					"CREATE INDEX Rule_networkId_ruleNo ON Rule (networkId, ruleNo);\n"
-					"CREATE INDEX Rule_networkId_policyId ON Rule (networkId, policyId);\n"
+					"CREATE INDEX Rule_networkId_capId ON Rule (networkId,capId);\n"
+					"CREATE TABLE MemberTC (\n"
+					"  networkId char(16) NOT NULL REFERENCES Network(id) ON DELETE CASCADE,\n"
+					"  nodeId char(10) NOT NULL REFERENCES Node(id) ON DELETE CASCADE,\n"
+					"  tagId integer,\n"
+					"  tagValue integer,\n"
+					"  capId integer,\n"
+					"  capMaxCustodyChainLength integer NOT NULL DEFAULT(1)\n"
+					");\n"
+					"CREATE INDEX MemberTC_networkId_nodeId ON MemberTC (networkId,nodeId);\n"
 					"UPDATE \"Config\" SET \"v\" = 5 WHERE \"k\" = 'schemaVersion';\n"
 				,0,0,0) != SQLITE_OK) {
 				char err[1024];
@@ -383,7 +251,6 @@ SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,c
 
 	if (
 
-			/* Network */
 			  (sqlite3_prepare_v2(_db,"SELECT name,private,enableBroadcast,allowPassiveBridging,\"flags\",multicastLimit,creationTime,revision,memberRevisionCounter,(SELECT COUNT(1) FROM Member WHERE Member.networkId = Network.id AND Member.authorized > 0) FROM Network WHERE id = ?",-1,&_sGetNetworkById,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"SELECT revision FROM Network WHERE id = ?",-1,&_sGetNetworkRevision,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"UPDATE Network SET revision = ? WHERE id = ?",-1,&_sSetNetworkRevision,(const char **)0) != SQLITE_OK)
@@ -392,33 +259,23 @@ SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,c
 			||(sqlite3_prepare_v2(_db,"SELECT id FROM Network ORDER BY id ASC",-1,&_sListNetworks,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"UPDATE Network SET memberRevisionCounter = (memberRevisionCounter + 1) WHERE id = ?",-1,&_sIncrementMemberRevisionCounter,(const char **)0) != SQLITE_OK)
 
-			/* Node */
 			||(sqlite3_prepare_v2(_db,"SELECT identity FROM Node WHERE id = ?",-1,&_sGetNodeIdentity,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"INSERT OR REPLACE INTO Node (id,identity) VALUES (?,?)",-1,&_sCreateOrReplaceNode,(const char **)0) != SQLITE_OK)
 
-			/* Rule */
 			||(sqlite3_prepare_v2(_db,"INSERT INTO Rule (networkId,ruleNo,nodeId,ztSource,ztDest,vlanId,vlanPcp,vlanDei,) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)",-1,&_sCreateRule,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"SELECT ruleNo,nodeId,sourcePort,destPort,vlanId,vlanPcp,etherType,macSource,macDest,ipSource,ipDest,ipTos,ipProtocol,ipSourcePort,ipDestPort,\"flags\",invFlags,\"action\" FROM Rule WHERE networkId = ? ORDER BY ruleNo ASC",-1,&_sListRules,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"DELETE FROM Rule WHERE networkId = ?",-1,&_sDeleteRulesForNetwork,(const char **)0) != SQLITE_OK)
 
-			/* IpAssignmentPool */
 			||(sqlite3_prepare_v2(_db,"SELECT ipRangeStart,ipRangeEnd FROM IpAssignmentPool WHERE networkId = ? AND ipVersion = ?",-1,&_sGetIpAssignmentPools,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"SELECT ipRangeStart,ipRangeEnd,ipVersion FROM IpAssignmentPool WHERE networkId = ? ORDER BY ipRangeStart ASC",-1,&_sGetIpAssignmentPools2,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"INSERT INTO IpAssignmentPool (networkId,ipRangeStart,ipRangeEnd,ipVersion) VALUES (?,?,?,?)",-1,&_sCreateIpAssignmentPool,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"DELETE FROM IpAssignmentPool WHERE networkId = ?",-1,&_sDeleteIpAssignmentPoolsForNetwork,(const char **)0) != SQLITE_OK)
 
-			/* IpAssignment */
 			||(sqlite3_prepare_v2(_db,"SELECT ip,ipNetmaskBits,ipVersion FROM IpAssignment WHERE networkId = ? AND nodeId = ? AND \"type\" = 0 ORDER BY ip ASC",-1,&_sGetIpAssignmentsForNode,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"SELECT 1 FROM IpAssignment WHERE networkId = ? AND ip = ? AND ipVersion = ? AND \"type\" = ?",-1,&_sCheckIfIpIsAllocated,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"INSERT INTO IpAssignment (networkId,nodeId,\"type\",ip,ipNetmaskBits,ipVersion) VALUES (?,?,?,?,?,?)",-1,&_sAllocateIp,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"DELETE FROM IpAssignment WHERE networkId = ? AND nodeId = ? AND \"type\" = ?",-1,&_sDeleteIpAllocations,(const char **)0) != SQLITE_OK)
 
-			/* Relay */
-			||(sqlite3_prepare_v2(_db,"SELECT \"address\",\"phyAddress\" FROM Relay WHERE \"networkId\" = ? ORDER BY \"address\" ASC",-1,&_sGetRelays,(const char **)0) != SQLITE_OK)
-			||(sqlite3_prepare_v2(_db,"DELETE FROM Relay WHERE networkId = ?",-1,&_sDeleteRelaysForNetwork,(const char **)0) != SQLITE_OK)
-			||(sqlite3_prepare_v2(_db,"INSERT INTO Relay (\"networkId\",\"address\",\"phyAddress\") VALUES (?,?,?)",-1,&_sCreateRelay,(const char **)0) != SQLITE_OK)
-
-			/* Member */
 			||(sqlite3_prepare_v2(_db,"SELECT rowid,authorized,activeBridge,memberRevision,\"flags\",lastRequestTime,recentHistory FROM Member WHERE networkId = ? AND nodeId = ?",-1,&_sGetMember,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"SELECT m.authorized,m.activeBridge,m.memberRevision,n.identity,m.flags,m.lastRequestTime,m.recentHistory FROM Member AS m LEFT OUTER JOIN Node AS n ON n.id = m.nodeId WHERE m.networkId = ? AND m.nodeId = ?",-1,&_sGetMember2,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"INSERT INTO Member (networkId,nodeId,authorized,activeBridge,memberRevision) VALUES (?,?,?,0,(SELECT memberRevisionCounter FROM Network WHERE id = ?))",-1,&_sCreateMember,(const char **)0) != SQLITE_OK)
@@ -431,12 +288,10 @@ SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,c
 			||(sqlite3_prepare_v2(_db,"DELETE FROM Member WHERE networkId = ?",-1,&_sDeleteAllNetworkMembers,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"SELECT nodeId,recentHistory FROM Member WHERE networkId = ? AND lastRequestTime >= ?",-1,&_sGetActiveNodesOnNetwork,(const char **)0) != SQLITE_OK)
 
-			/* Route */
 			||(sqlite3_prepare_v2(_db,"INSERT INTO Route (networkId,target,via,targetNetmaskBits,ipVersion,flags,metric) VALUES (?,?,?,?,?,?,?)",-1,&_sCreateRoute,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"SELECT DISTINCT target,via,targetNetmaskBits,ipVersion,flags,metric FROM \"Route\" WHERE networkId = ? ORDER BY ipVersion,target,via",-1,&_sGetRoutes,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"DELETE FROM \"Route\" WHERE networkId = ?",-1,&_sDeleteRoutes,(const char **)0) != SQLITE_OK)
 
-			/* Config */
 			||(sqlite3_prepare_v2(_db,"SELECT \"v\" FROM \"Config\" WHERE \"k\" = ?",-1,&_sGetConfig,(const char **)0) != SQLITE_OK)
 			||(sqlite3_prepare_v2(_db,"INSERT OR REPLACE INTO \"Config\" (\"k\",\"v\") VALUES (?,?)",-1,&_sSetConfig,(const char **)0) != SQLITE_OK)
 
@@ -446,9 +301,6 @@ SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,c
 		throw std::runtime_error(err);
 	}
 
-	/* Generate a 128-bit / 32-character "instance ID" if one isn't already
-	 * defined. Clients can use this to determine if this is the same controller
-	 * database they know and love. */
 	sqlite3_reset(_sGetConfig);
 	sqlite3_bind_text(_sGetConfig,1,"instanceId",10,SQLITE_STATIC);
 	if (sqlite3_step(_sGetConfig) != SQLITE_ROW) {
@@ -474,72 +326,32 @@ SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,c
 #endif
 
 	_backupThread = Thread::start(this);
+	*/
+
+	_dbCommitThread = Thread::start(this);
 }
 
 SqliteNetworkController::~SqliteNetworkController()
 {
-	_backupThreadRun = false;
-	Thread::join(_backupThread);
-
-	Mutex::Lock _l(_lock);
-	if (_db) {
-		sqlite3_finalize(_sGetNetworkById);
-		sqlite3_finalize(_sGetMember);
-		sqlite3_finalize(_sCreateMember);
-		sqlite3_finalize(_sGetNodeIdentity);
-		sqlite3_finalize(_sCreateOrReplaceNode);
-		sqlite3_finalize(_sGetActiveBridges);
-		sqlite3_finalize(_sGetIpAssignmentsForNode);
-		sqlite3_finalize(_sGetIpAssignmentPools);
-		sqlite3_finalize(_sCheckIfIpIsAllocated);
-		sqlite3_finalize(_sAllocateIp);
-		sqlite3_finalize(_sDeleteIpAllocations);
-		sqlite3_finalize(_sGetRelays);
-		sqlite3_finalize(_sListNetworks);
-		sqlite3_finalize(_sListNetworkMembers);
-		sqlite3_finalize(_sGetMember2);
-		sqlite3_finalize(_sGetIpAssignmentPools2);
-		sqlite3_finalize(_sListRules);
-		sqlite3_finalize(_sCreateRule);
-		sqlite3_finalize(_sCreateNetwork);
-		sqlite3_finalize(_sGetNetworkRevision);
-		sqlite3_finalize(_sSetNetworkRevision);
-		sqlite3_finalize(_sDeleteRelaysForNetwork);
-		sqlite3_finalize(_sCreateRelay);
-		sqlite3_finalize(_sDeleteIpAssignmentPoolsForNetwork);
-		sqlite3_finalize(_sDeleteRulesForNetwork);
-		sqlite3_finalize(_sCreateIpAssignmentPool);
-		sqlite3_finalize(_sUpdateMemberAuthorized);
-		sqlite3_finalize(_sUpdateMemberActiveBridge);
-		sqlite3_finalize(_sUpdateMemberHistory);
-		sqlite3_finalize(_sDeleteMember);
-		sqlite3_finalize(_sDeleteAllNetworkMembers);
-		sqlite3_finalize(_sGetActiveNodesOnNetwork);
-		sqlite3_finalize(_sDeleteNetwork);
-		sqlite3_finalize(_sCreateRoute);
-		sqlite3_finalize(_sGetRoutes);
-		sqlite3_finalize(_sDeleteRoutes);
-		sqlite3_finalize(_sIncrementMemberRevisionCounter);
-		sqlite3_finalize(_sGetConfig);
-		sqlite3_finalize(_sSetConfig);
-		sqlite3_close(_db);
-	}
+	_lock.lock();
+	_dbCommitThreadRun = false;
+	_lock.unlock();
+	Thread::join(_dbCommitThread);
 }
 
-NetworkController::ResultCode SqliteNetworkController::doNetworkConfigRequest(const InetAddress &fromAddr,const Identity &signingId,const Identity &identity,uint64_t nwid,const Dictionary<ZT_NETWORKCONFIG_DICT_CAPACITY> &metaData,NetworkConfig &nc)
+NetworkController::ResultCode SqliteNetworkController::doNetworkConfigRequest(const InetAddress &fromAddr,const Identity &signingId,const Identity &identity,uint64_t nwid,const Dictionary<ZT_NETWORKCONFIG_METADATA_DICT_CAPACITY> &metaData,NetworkConfig &nc)
 {
 	if (((!signingId)||(!signingId.hasPrivate()))||(signingId.address().toInt() != (nwid >> 24))) {
 		return NetworkController::NETCONF_QUERY_INTERNAL_SERVER_ERROR;
 	}
 
-	const uint64_t now = OSUtils::now();
-
-	NetworkRecord network;
-	Utils::snprintf(network.id,sizeof(network.id),"%.16llx",(unsigned long long)nwid);
+	char nwids[24],nodeIds[24];
+	Utils::snprintf(nwids,sizeof(nwids),"%.16llx",(unsigned long long)nwid);
+	Utils::snprintf(nodeIds,sizeof(nodeIds),"%.10llx",(unsigned long long)identity.address().toInt());
 
-	MemberRecord member;
-	Utils::snprintf(member.nodeId,sizeof(member.nodeId),"%.10llx",(unsigned long long)identity.address().toInt());
+	const uint64_t now = OSUtils::now();
 
+	/*
 	{ // begin lock
 		Mutex::Lock _l(_lock);
 
@@ -874,13 +686,13 @@ NetworkController::ResultCode SqliteNetworkController::doNetworkConfigRequest(co
 						sqlite3_bind_text(_sCheckIfIpIsAllocated,1,network.id,16,SQLITE_STATIC);
 						sqlite3_bind_blob(_sCheckIfIpIsAllocated,2,(const void *)ip6.rawIpData(),16,SQLITE_STATIC);
 						sqlite3_bind_int(_sCheckIfIpIsAllocated,3,6); // 6 == IPv6
-						sqlite3_bind_int(_sCheckIfIpIsAllocated,4,(int)0 /*ZT_IP_ASSIGNMENT_TYPE_ADDRESS*/);
+						sqlite3_bind_int(_sCheckIfIpIsAllocated,4,(int)0);
 						if (sqlite3_step(_sCheckIfIpIsAllocated) != SQLITE_ROW) {
 							// No rows returned, so the IP is available
 							sqlite3_reset(_sAllocateIp);
 							sqlite3_bind_text(_sAllocateIp,1,network.id,16,SQLITE_STATIC);
 							sqlite3_bind_text(_sAllocateIp,2,member.nodeId,10,SQLITE_STATIC);
-							sqlite3_bind_int(_sAllocateIp,3,(int)0 /*ZT_IP_ASSIGNMENT_TYPE_ADDRESS*/);
+							sqlite3_bind_int(_sAllocateIp,3,(int)0);
 							sqlite3_bind_blob(_sAllocateIp,4,(const void *)ip6.rawIpData(),16,SQLITE_STATIC);
 							sqlite3_bind_int(_sAllocateIp,5,routedNetmaskBits); // IP netmask bits from matching route
 							sqlite3_bind_int(_sAllocateIp,6,6); // 6 == IPv6
@@ -943,13 +755,13 @@ NetworkController::ResultCode SqliteNetworkController::doNetworkConfigRequest(co
 						sqlite3_bind_text(_sCheckIfIpIsAllocated,1,network.id,16,SQLITE_STATIC);
 						sqlite3_bind_blob(_sCheckIfIpIsAllocated,2,(const void *)ipBlob,16,SQLITE_STATIC);
 						sqlite3_bind_int(_sCheckIfIpIsAllocated,3,4); // 4 == IPv4
-						sqlite3_bind_int(_sCheckIfIpIsAllocated,4,(int)0 /*ZT_IP_ASSIGNMENT_TYPE_ADDRESS*/);
+						sqlite3_bind_int(_sCheckIfIpIsAllocated,4,(int)0);
 						if (sqlite3_step(_sCheckIfIpIsAllocated) != SQLITE_ROW) {
 							// No rows returned, so the IP is available
 							sqlite3_reset(_sAllocateIp);
 							sqlite3_bind_text(_sAllocateIp,1,network.id,16,SQLITE_STATIC);
 							sqlite3_bind_text(_sAllocateIp,2,member.nodeId,10,SQLITE_STATIC);
-							sqlite3_bind_int(_sAllocateIp,3,(int)0 /*ZT_IP_ASSIGNMENT_TYPE_ADDRESS*/);
+							sqlite3_bind_int(_sAllocateIp,3,(int)0);
 							sqlite3_bind_blob(_sAllocateIp,4,(const void *)ipBlob,16,SQLITE_STATIC);
 							sqlite3_bind_int(_sAllocateIp,5,routedNetmaskBits); // IP netmask bits from matching route
 							sqlite3_bind_int(_sAllocateIp,6,4); // 4 == IPv4
@@ -980,6 +792,7 @@ NetworkController::ResultCode SqliteNetworkController::doNetworkConfigRequest(co
 	}
 
 	return NetworkController::NETCONF_QUERY_OK;
+	*/
 }
 
 unsigned int SqliteNetworkController::handleControlPlaneHttpGET(
@@ -1671,76 +1484,19 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpDELETE(
 void SqliteNetworkController::threadMain()
 	throw()
 {
-	uint64_t lastBackupTime = OSUtils::now();
-	uint64_t lastCleanupTime = OSUtils::now();
-
-	while (_backupThreadRun) {
-		if ((OSUtils::now() - lastCleanupTime) >= 5000) {
-			const uint64_t now = OSUtils::now();
-			lastCleanupTime = now;
-
+	bool run = true;
+	while(run) {
+		Thread::sleep(250);
+		try {
+			std::vector<std::string> errors;
 			Mutex::Lock _l(_lock);
-
-			// Clean out really old circuit tests to prevent memory build-up
-			for(std::map< uint64_t,_CircuitTestEntry >::iterator ct(_circuitTests.begin());ct!=_circuitTests.end();) {
-				if (!ct->second.test) {
-					_circuitTests.erase(ct++);
-				} else if ((now - ct->second.test->timestamp) >= ZT_SQLITENETWORKCONTROLLER_CIRCUIT_TEST_TIMEOUT) {
-					_node->circuitTestEnd(ct->second.test);
-					::free((void *)ct->second.test);
-					_circuitTests.erase(ct++);
-				} else ++ct;
+			run = _dbCommitThreadRun;
+			if (!_db.commit(&errors)) {
+				// TODO: handle anything really bad
 			}
+		} catch ( ... ) {
+			// TODO: handle anything really bad
 		}
-
-		if (((OSUtils::now() - lastBackupTime) >= ZT_NETCONF_BACKUP_PERIOD)&&(_backupNeeded)) {
-			lastBackupTime = OSUtils::now();
-
-			char backupPath[4096],backupPath2[4096];
-			Utils::snprintf(backupPath,sizeof(backupPath),"%s.backupInProgress",_dbPath.c_str());
-			Utils::snprintf(backupPath2,sizeof(backupPath),"%s.backup",_dbPath.c_str());
-			OSUtils::rm(backupPath); // delete any unfinished backups
-
-			sqlite3 *bakdb = (sqlite3 *)0;
-			sqlite3_backup *bak = (sqlite3_backup *)0;
-			if (sqlite3_open_v2(backupPath,&bakdb,SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE,(const char *)0) != SQLITE_OK) {
-				fprintf(stderr,"SqliteNetworkController: CRITICAL: backup failed on sqlite3_open_v2()"ZT_EOL_S);
-				continue;
-			}
-			bak = sqlite3_backup_init(bakdb,"main",_db,"main");
-			if (!bak) {
-				sqlite3_close(bakdb);
-				OSUtils::rm(backupPath); // delete any unfinished backups
-				fprintf(stderr,"SqliteNetworkController: CRITICAL: backup failed on sqlite3_backup_init()"ZT_EOL_S);
-				continue;
-			}
-
-			int rc = SQLITE_OK;
-			for(;;) {
-				if (!_backupThreadRun) {
-					sqlite3_backup_finish(bak);
-					sqlite3_close(bakdb);
-					OSUtils::rm(backupPath);
-					return;
-				}
-				_lock.lock();
-				rc = sqlite3_backup_step(bak,64);
-				_lock.unlock();
-				if ((rc == SQLITE_OK)||(rc == SQLITE_LOCKED)||(rc == SQLITE_BUSY))
-					Thread::sleep(50);
-				else break;
-			}
-
-			sqlite3_backup_finish(bak);
-			sqlite3_close(bakdb);
-
-			OSUtils::rm(backupPath2);
-			::rename(backupPath,backupPath2);
-
-			_backupNeeded = false;
-		}
-
-		Thread::sleep(250);
 	}
 }
 
@@ -1753,27 +1509,40 @@ unsigned int SqliteNetworkController::_doCPGet(
 	std::string &responseContentType)
 {
 	// Assumes _lock is locked
-	char json[65536];
-
 	if ((path.size() > 0)&&(path[0] == "network")) {
+		auto networks = _db.get<const json::object_t *>("network");
+		if (!networks) return 404;
 
 		if ((path.size() >= 2)&&(path[1].length() == 16)) {
-			uint64_t nwid = Utils::hexStrToU64(path[1].c_str());
+			const uint64_t nwid = Utils::hexStrToU64(path[1].c_str());
 			char nwids[24];
 			Utils::snprintf(nwids,sizeof(nwids),"%.16llx",(unsigned long long)nwid);
+			auto network = _db.get<const json::object_t *>(nwids);
+			if (!network) return 404;
 
 			if (path.size() >= 3) {
-				// /network/<nwid>/...
 
 				if (path[2] == "member") {
+					auto members = network->get<const json::object_t *>("member");
+					if (!members) return 404;
 
 					if (path.size() >= 4) {
-						// Get specific member info
-
-						uint64_t address = Utils::hexStrToU64(path[3].c_str());
+						const uint64_t address = Utils::hexStrToU64(path[3].c_str());
 						char addrs[24];
 						Utils::snprintf(addrs,sizeof(addrs),"%.10llx",address);
+						auto member = members->get<const json::object_t *>(addrs);
+						if (!member) return 404;
+
+						nlohmann::json o(member);
+						o["nwid"] = nwids;
+						o["address"] = addrs;
+						o["controllerInstanceId"] = _instanceId;
+						o["clock"] = OSUtils::now();
+						responseBody = o.dump(2);
+						responseContentType = "application/json";
+						return 200;
 
+						/*
 						sqlite3_reset(_sGetMember2);
 						sqlite3_bind_text(_sGetMember2,1,nwids,16,SQLITE_STATIC);
 						sqlite3_bind_text(_sGetMember2,2,addrs,10,SQLITE_STATIC);
@@ -1838,20 +1607,18 @@ unsigned int SqliteNetworkController::_doCPGet(
 							responseContentType = "application/json";
 							return 200;
 						} // else 404
+						*/
 
 					} else {
-						// List members
 
-						sqlite3_reset(_sListNetworkMembers);
-						sqlite3_bind_text(_sListNetworkMembers,1,nwids,16,SQLITE_STATIC);
 						responseBody.push_back('{');
-						bool firstMember = true;
-						while (sqlite3_step(_sListNetworkMembers) == SQLITE_ROW) {
-							responseBody.append(firstMember ? "\"" : ",\"");
-							firstMember = false;
-							responseBody.append((const char *)sqlite3_column_text(_sListNetworkMembers,0));
-							responseBody.append("\":");
-							responseBody.append((const char *)sqlite3_column_text(_sListNetworkMembers,1));
+						for(auto i(members->begin());i!=members->end();++i) {
+							responseBody.append((i == members->begin()) ? "\"" : ",\"");
+							responseBody.append(i->key());
+							responseBody.append("\":\"");
+							const std::string rc = i->value().value("memberRevision","0");
+							responseBody.append(rc);
+							responseBody.append('"');
 						}
 						responseBody.push_back('}');
 						responseContentType = "application/json";
@@ -1861,33 +1628,23 @@ unsigned int SqliteNetworkController::_doCPGet(
 
 				} else if ((path[2] == "active")&&(path.size() == 3)) {
 
-					sqlite3_reset(_sGetActiveNodesOnNetwork);
-					sqlite3_bind_text(_sGetActiveNodesOnNetwork,1,nwids,16,SQLITE_STATIC);
-					sqlite3_bind_int64(_sGetActiveNodesOnNetwork,2,(int64_t)(OSUtils::now() - ZT_NETCONF_NODE_ACTIVE_THRESHOLD));
-
 					responseBody.push_back('{');
-					bool firstActiveMember = true;
-					while (sqlite3_step(_sGetActiveNodesOnNetwork) == SQLITE_ROW) {
-						const char *nodeId = (const char *)sqlite3_column_text(_sGetActiveNodesOnNetwork,0);
-						const char *rhblob = (const char *)sqlite3_column_blob(_sGetActiveNodesOnNetwork,1);
-						if ((nodeId)&&(rhblob)) {
-							MemberRecentHistory rh;
-							rh.fromBlob(rhblob,sqlite3_column_bytes(_sGetActiveNodesOnNetwork,1));
-							if (rh.size() > 0) {
-								if (firstActiveMember) {
-									firstActiveMember = false;
-								} else {
-									responseBody.push_back(',');
-								}
-								responseBody.push_back('"');
-								responseBody.append(nodeId);
+					bool firstMember = true;
+					const uint64_t threshold = OSUtils::now() - ZT_NETCONF_NODE_ACTIVE_THRESHOLD;
+					for(auto i(members->begin());i!=members->end();++i) {
+						auto recentLog = i->value()->get<const json::array_t *>("recentLog");
+						if ((recentLog)&&(recentLog.size() > 0)) {
+							auto mostRecentLog = recentLog[0];
+							if ((mostRecentLog.is_object())&&((uint64_t)mostRecentLog.value("ts",0ULL) >= threshold)) {
+								responseBody.append((firstMember) ? "\"" : ",\"");
+								firstMember = false;
+								responseBody.append(i->key());
 								responseBody.append("\":");
-								responseBody.append(rh.front());
+								responseBody.append(mostRecentLog.dump());
 							}
 						}
 					}
 					responseBody.push_back('}');
-
 					responseContentType = "application/json";
 					return 200;
 
@@ -1909,249 +1666,42 @@ unsigned int SqliteNetworkController::_doCPGet(
 
 			} else {
 
-				sqlite3_reset(_sGetNetworkById);
-				sqlite3_bind_text(_sGetNetworkById,1,nwids,16,SQLITE_STATIC);
-				if (sqlite3_step(_sGetNetworkById) == SQLITE_ROW) {
-					unsigned int fl = (unsigned int)sqlite3_column_int(_sGetNetworkById,4);
-					std::string v6modes;
-					if ((fl & ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_RFC4193) != 0)
-						v6modes.append("rfc4193");
-					if ((fl & ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_6PLANE) != 0) {
-						if (v6modes.length() > 0)
-							v6modes.push_back(',');
-						v6modes.append("6plane");
-					}
-					if ((fl & ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_AUTO_ASSIGN) != 0) {
-						if (v6modes.length() > 0)
-							v6modes.push_back(',');
-						v6modes.append("zt");
-					}
-
-					Utils::snprintf(json,sizeof(json),
-						"{\n"
-						"\t\"nwid\": \"%s\",\n"
-						"\t\"controllerInstanceId\": \"%s\",\n"
-						"\t\"clock\": %llu,\n"
-						"\t\"name\": \"%s\",\n"
-						"\t\"private\": %s,\n"
-						"\t\"enableBroadcast\": %s,\n"
-						"\t\"allowPassiveBridging\": %s,\n"
-						"\t\"v4AssignMode\": \"%s\",\n"
-						"\t\"v6AssignMode\": \"%s\",\n"
-						"\t\"multicastLimit\": %d,\n"
-						"\t\"creationTime\": %llu,\n"
-						"\t\"revision\": %llu,\n"
-						"\t\"memberRevisionCounter\": %llu,\n"
-						"\t\"authorizedMemberCount\": %llu,\n"
-						"\t\"relays\": [",
-						nwids,
-						_instanceId.c_str(),
-						(unsigned long long)OSUtils::now(),
-						_jsonEscape((const char *)sqlite3_column_text(_sGetNetworkById,0)).c_str(),
-						(sqlite3_column_int(_sGetNetworkById,1) > 0) ? "true" : "false",
-						(sqlite3_column_int(_sGetNetworkById,2) > 0) ? "true" : "false",
-						(sqlite3_column_int(_sGetNetworkById,3) > 0) ? "true" : "false",
-						(((fl & ZT_DB_NETWORK_FLAG_ZT_MANAGED_V4_AUTO_ASSIGN) != 0) ? "zt" : ""),
-						v6modes.c_str(),
-						sqlite3_column_int(_sGetNetworkById,5),
-						(unsigned long long)sqlite3_column_int64(_sGetNetworkById,6),
-						(unsigned long long)sqlite3_column_int64(_sGetNetworkById,7),
-						(unsigned long long)sqlite3_column_int64(_sGetNetworkById,8),
-						(unsigned long long)sqlite3_column_int64(_sGetNetworkById,9));
-					responseBody = json;
-
-					sqlite3_reset(_sGetRelays);
-					sqlite3_bind_text(_sGetRelays,1,nwids,16,SQLITE_STATIC);
-					bool firstRelay = true;
-					while (sqlite3_step(_sGetRelays) == SQLITE_ROW) {
-						responseBody.append(firstRelay ? "\n\t\t" : ",\n\t\t");
-						firstRelay = false;
-						responseBody.append("{\"address\":\"");
-						responseBody.append((const char *)sqlite3_column_text(_sGetRelays,0));
-						responseBody.append("\",\"phyAddress\":\"");
-						responseBody.append(_jsonEscape((const char *)sqlite3_column_text(_sGetRelays,1)));
-						responseBody.append("\"}");
-					}
-
-					responseBody.append("],\n\t\"routes\": [");
-
-					sqlite3_reset(_sGetRoutes);
-					sqlite3_bind_text(_sGetRoutes,1,nwids,16,SQLITE_STATIC);
-					bool firstRoute = true;
-					while (sqlite3_step(_sGetRoutes) == SQLITE_ROW) {
-						responseBody.append(firstRoute ? "\n\t\t" : ",\n\t\t");
-						firstRoute = false;
-						responseBody.append("{\"target\":");
-						char tmp[128];
-						const unsigned char *ip = (const unsigned char *)sqlite3_column_blob(_sGetRoutes,0);
-						switch(sqlite3_column_int(_sGetRoutes,3)) { // ipVersion
-							case 4:
-								Utils::snprintf(tmp,sizeof(tmp),"\"%d.%d.%d.%d/%d\"",(int)ip[12],(int)ip[13],(int)ip[14],(int)ip[15],sqlite3_column_int(_sGetRoutes,2));
-								break;
-							case 6:
-								Utils::snprintf(tmp,sizeof(tmp),"\"%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x/%d\"",(int)ip[0],(int)ip[1],(int)ip[2],(int)ip[3],(int)ip[4],(int)ip[5],(int)ip[6],(int)ip[7],(int)ip[8],(int)ip[9],(int)ip[10],(int)ip[11],(int)ip[12],(int)ip[13],(int)ip[14],(int)ip[15],sqlite3_column_int(_sGetRoutes,2));
-								break;
-						}
-						responseBody.append(tmp);
-						if (sqlite3_column_type(_sGetRoutes,1) == SQLITE_NULL) {
-							responseBody.append(",\"via\":null");
-						} else {
-							responseBody.append(",\"via\":");
-							ip = (const unsigned char *)sqlite3_column_blob(_sGetRoutes,1);
-							switch(sqlite3_column_int(_sGetRoutes,3)) { // ipVersion
-								case 4:
-									Utils::snprintf(tmp,sizeof(tmp),"\"%d.%d.%d.%d\"",(int)ip[12],(int)ip[13],(int)ip[14],(int)ip[15]);
-									break;
-								case 6:
-									Utils::snprintf(tmp,sizeof(tmp),"\"%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x\"",(int)ip[0],(int)ip[1],(int)ip[2],(int)ip[3],(int)ip[4],(int)ip[5],(int)ip[6],(int)ip[7],(int)ip[8],(int)ip[9],(int)ip[10],(int)ip[11],(int)ip[12],(int)ip[13],(int)ip[14],(int)ip[15]);
-									break;
-							}
-							responseBody.append(tmp);
-						}
-						responseBody.append(",\"flags\":");
-						responseBody.append((const char *)sqlite3_column_text(_sGetRoutes,4));
-						responseBody.append(",\"metric\":");
-						responseBody.append((const char *)sqlite3_column_text(_sGetRoutes,5));
-						responseBody.push_back('}');
-					}
-
-					responseBody.append("],\n\t\"ipAssignmentPools\": [");
-
-					sqlite3_reset(_sGetIpAssignmentPools2);
-					sqlite3_bind_text(_sGetIpAssignmentPools2,1,nwids,16,SQLITE_STATIC);
-					bool firstIpAssignmentPool = true;
-					while (sqlite3_step(_sGetIpAssignmentPools2) == SQLITE_ROW) {
-						const char *ipRangeStartB = reinterpret_cast<const char *>(sqlite3_column_blob(_sGetIpAssignmentPools2,0));
-						const char *ipRangeEndB = reinterpret_cast<const char *>(sqlite3_column_blob(_sGetIpAssignmentPools2,1));
-						if ((ipRangeStartB)&&(ipRangeEndB)) {
-							InetAddress ipps,ippe;
-							int ipVersion = sqlite3_column_int(_sGetIpAssignmentPools2,2);
-							if (ipVersion == 4) {
-								ipps.set((const void *)(ipRangeStartB + 12),4,0);
-								ippe.set((const void *)(ipRangeEndB + 12),4,0);
-							} else if (ipVersion == 6) {
-								ipps.set((const void *)ipRangeStartB,16,0);
-								ippe.set((const void *)ipRangeEndB,16,0);
-							}
-							if (ipps) {
-								responseBody.append(firstIpAssignmentPool ? "\n\t\t" : ",\n\t\t");
-								firstIpAssignmentPool = false;
-								Utils::snprintf(json,sizeof(json),"{\"ipRangeStart\":\"%s\",\"ipRangeEnd\":\"%s\"}",
-									_jsonEscape(ipps.toIpString()).c_str(),
-									_jsonEscape(ippe.toIpString()).c_str());
-								responseBody.append(json);
-							}
-						}
-					}
+				nlohmann::json o(network);
+				o["nwid"] = nwids;
+				o["controllerInstanceId"] = _instanceId;
+				o["clock"] = OSUtils::now();
+				responseBody = o.dump(2);
+				responseContentType = "application/json";
+				return 200;
 
-					responseBody.append("],\n\t\"rules\": [");
-
-					sqlite3_reset(_sListRules);
-					sqlite3_bind_text(_sListRules,1,nwids,16,SQLITE_STATIC);
-					bool firstRule = true;
-					while (sqlite3_step(_sListRules) == SQLITE_ROW) {
-						responseBody.append(firstRule ? "\n\t{\n" : ",{\n");
-						firstRule = false;
-						Utils::snprintf(json,sizeof(json),"\t\t\"ruleNo\": %lld,\n",sqlite3_column_int64(_sListRules,0));
-						responseBody.append(json);
-						if (sqlite3_column_type(_sListRules,1) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"nodeId\": \"%s\",\n",(const char *)sqlite3_column_text(_sListRules,1));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,2) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"sourcePort\": \"%s\",\n",(const char *)sqlite3_column_text(_sListRules,2));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,3) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"destPort\": \"%s\",\n",(const char *)sqlite3_column_text(_sListRules,3));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,4) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"vlanId\": %d,\n",sqlite3_column_int(_sListRules,4));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,5) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"vlanPcp\": %d,\n",sqlite3_column_int(_sListRules,5));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,6) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"etherType\": %d,\n",sqlite3_column_int(_sListRules,6));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,7) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"macSource\": \"%s\",\n",MAC((const char *)sqlite3_column_text(_sListRules,7)).toString().c_str());
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,8) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"macDest\": \"%s\",\n",MAC((const char *)sqlite3_column_text(_sListRules,8)).toString().c_str());
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,9) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"ipSource\": \"%s\",\n",_jsonEscape((const char *)sqlite3_column_text(_sListRules,9)).c_str());
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,10) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"ipDest\": \"%s\",\n",_jsonEscape((const char *)sqlite3_column_text(_sListRules,10)).c_str());
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,11) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"ipTos\": %d,\n",sqlite3_column_int(_sListRules,11));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,12) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"ipProtocol\": %d,\n",sqlite3_column_int(_sListRules,12));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,13) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"ipSourcePort\": %d,\n",sqlite3_column_int(_sListRules,13));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,14) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"ipDestPort\": %d,\n",sqlite3_column_int(_sListRules,14));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,15) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"flags\": %lu,\n",(unsigned long)sqlite3_column_int64(_sListRules,15));
-							responseBody.append(json);
-						}
-						if (sqlite3_column_type(_sListRules,16) != SQLITE_NULL) {
-							Utils::snprintf(json,sizeof(json),"\t\t\"invFlags\": %lu,\n",(unsigned long)sqlite3_column_int64(_sListRules,16));
-							responseBody.append(json);
-						}
-						responseBody.append("\t\t\"action\": \"");
-						responseBody.append(_jsonEscape( (sqlite3_column_type(_sListRules,17) == SQLITE_NULL) ? "drop" : (const char *)sqlite3_column_text(_sListRules,17) ));
-						responseBody.append("\"\n\t}");
-					}
-
-					responseBody.append("]\n}\n");
-					responseContentType = "application/json";
-					return 200;
-				} // else 404
 			}
 		} else if (path.size() == 1) {
-			// list networks
-			sqlite3_reset(_sListNetworks);
-			responseContentType = "application/json";
+
 			responseBody = "[";
-			bool first = true;
-			while (sqlite3_step(_sListNetworks) == SQLITE_ROW) {
-				if (first) {
-					first = false;
-					responseBody.push_back('"');
-				} else responseBody.append(",\"");
-				responseBody.append((const char *)sqlite3_column_text(_sListNetworks,0));
-				responseBody.push_back('"');
+			for(auto i(networks->begin());i!=networks.end();++i) {
+				responseBody.append((i == networks->begin()) ? "\"" : ",\"");
+				responseBody.append(i->key());
+				responseBody.append("\"");
 			}
 			responseBody.push_back(']');
+			responseContentType = "application/json";
 			return 200;
+
 		} // else 404
 
+	} else if ((path.size() > 0)&&(path[0] == "_dump")) {
+
+		responseBody = _db.dump(2);
+		responseContentType = "application/json";
+		return 200;
+
 	} else {
-		// GET /controller returns status and API version if controller is supported
+
 		Utils::snprintf(json,sizeof(json),"{\n\t\"controller\": true,\n\t\"apiVersion\": %d,\n\t\"clock\": %llu,\n\t\"instanceId\": \"%s\"\n}\n",ZT_NETCONF_CONTROLLER_API_VERSION,(unsigned long long)OSUtils::now(),_instanceId.c_str());
 		responseBody = json;
 		responseContentType = "application/json";
 		return 200;
+
 	}
 
 	return 404;
diff --git a/controller/SqliteNetworkController.hpp b/controller/SqliteNetworkController.hpp
index b917f6fb..0d549abc 100644
--- a/controller/SqliteNetworkController.hpp
+++ b/controller/SqliteNetworkController.hpp
@@ -30,22 +30,17 @@
 
 #include <stdint.h>
 
-#include <sqlite3.h>
-
 #include <string>
 #include <map>
 #include <vector>
 
 #include "../node/Constants.hpp"
+
 #include "../node/NetworkController.hpp"
 #include "../node/Mutex.hpp"
 #include "../osdep/Thread.hpp"
 
-// Number of in-memory last log entries to maintain per user
-#define ZT_SQLITENETWORKCONTROLLER_IN_MEMORY_LOG_SIZE 32
-
-// How long do circuit tests last before they're forgotten?
-#define ZT_SQLITENETWORKCONTROLLER_CIRCUIT_TEST_TIMEOUT 60000
+#include "../ext/offbase/offbase.hpp"
 
 namespace ZeroTier {
 
@@ -54,7 +49,7 @@ class Node;
 class SqliteNetworkController : public NetworkController
 {
 public:
-	SqliteNetworkController(Node *node,const char *dbPath,const char *circuitTestPath);
+	SqliteNetworkController(Node *node,const char *dbPath);
 	virtual ~SqliteNetworkController();
 
 	virtual NetworkController::ResultCode doNetworkConfigRequest(
@@ -62,7 +57,7 @@ public:
 		const Identity &signingId,
 		const Identity &identity,
 		uint64_t nwid,
-		const Dictionary<ZT_NETWORKCONFIG_DICT_CAPACITY> &metaData,
+		const Dictionary<ZT_NETWORKCONFIG_METADATA_DICT_CAPACITY> &metaData,
 		NetworkConfig &nc);
 
 	unsigned int handleControlPlaneHttpGET(
@@ -92,15 +87,6 @@ public:
 		throw();
 
 private:
-	/* deprecated
-	enum IpAssignmentType {
-		// IP assignment is a static IP address
-		ZT_IP_ASSIGNMENT_TYPE_ADDRESS = 0,
-		// IP assignment is a network -- a route via this interface, not an address
-		ZT_IP_ASSIGNMENT_TYPE_NETWORK = 1
-	};
-	*/
-
 	unsigned int _doCPGet(
 		const std::vector<std::string> &path,
 		const std::map<std::string,std::string> &urlArgs,
@@ -111,13 +97,11 @@ private:
 
 	static void _circuitTestCallback(ZT_Node *node,ZT_CircuitTest *test,const ZT_CircuitTestReport *report);
 
-	Node *_node;
-	Thread _backupThread;
-	volatile bool _backupThreadRun;
-	volatile bool _backupNeeded;
-	std::string _dbPath;
-	std::string _circuitTestPath;
+	Node *const _node;
 	std::string _instanceId;
+	offbase _db;
+	Thread _dbCommitThread;
+	volatile bool _dbCommitThreadRun;
 
 	// Circuit tests outstanding
 	struct _CircuitTestEntry
@@ -130,48 +114,6 @@ private:
 	// Last request time by address, for rate limitation
 	std::map< std::pair<uint64_t,uint64_t>,uint64_t > _lastRequestTime;
 
-	sqlite3 *_db;
-
-	sqlite3_stmt *_sGetNetworkById;
-	sqlite3_stmt *_sGetMember;
-	sqlite3_stmt *_sCreateMember;
-	sqlite3_stmt *_sGetNodeIdentity;
-	sqlite3_stmt *_sCreateOrReplaceNode;
-	sqlite3_stmt *_sGetActiveBridges;
-	sqlite3_stmt *_sGetIpAssignmentsForNode;
-	sqlite3_stmt *_sGetIpAssignmentPools;
-	sqlite3_stmt *_sCheckIfIpIsAllocated;
-	sqlite3_stmt *_sAllocateIp;
-	sqlite3_stmt *_sDeleteIpAllocations;
-	sqlite3_stmt *_sGetRelays;
-	sqlite3_stmt *_sListNetworks;
-	sqlite3_stmt *_sListNetworkMembers;
-	sqlite3_stmt *_sGetMember2;
-	sqlite3_stmt *_sGetIpAssignmentPools2;
-	sqlite3_stmt *_sListRules;
-	sqlite3_stmt *_sCreateRule;
-	sqlite3_stmt *_sCreateNetwork;
-	sqlite3_stmt *_sGetNetworkRevision;
-	sqlite3_stmt *_sSetNetworkRevision;
-	sqlite3_stmt *_sDeleteRelaysForNetwork;
-	sqlite3_stmt *_sCreateRelay;
-	sqlite3_stmt *_sDeleteIpAssignmentPoolsForNetwork;
-	sqlite3_stmt *_sDeleteRulesForNetwork;
-	sqlite3_stmt *_sCreateIpAssignmentPool;
-	sqlite3_stmt *_sUpdateMemberAuthorized;
-	sqlite3_stmt *_sUpdateMemberActiveBridge;
-	sqlite3_stmt *_sUpdateMemberHistory;
-	sqlite3_stmt *_sDeleteMember;
-	sqlite3_stmt *_sDeleteAllNetworkMembers;
-	sqlite3_stmt *_sGetActiveNodesOnNetwork;
-	sqlite3_stmt *_sDeleteNetwork;
-	sqlite3_stmt *_sCreateRoute;
-	sqlite3_stmt *_sGetRoutes;
-	sqlite3_stmt *_sDeleteRoutes;
-	sqlite3_stmt *_sIncrementMemberRevisionCounter;
-	sqlite3_stmt *_sGetConfig;
-	sqlite3_stmt *_sSetConfig;
-
 	Mutex _lock;
 };
 
diff --git a/controller/schema.sql b/controller/schema.sql
index 479daa68..d1daf8d0 100644
--- a/controller/schema.sql
+++ b/controller/schema.sql
@@ -86,17 +86,9 @@ CREATE TABLE Route (
 
 CREATE INDEX Route_networkId ON Route (networkId);
 
-CREATE TABLE Relay (
-  networkId char(16) NOT NULL REFERENCES Network(id) ON DELETE CASCADE,
-  address char(10) NOT NULL,
-  phyAddress varchar(64) NOT NULL
-);
-
-CREATE UNIQUE INDEX Relay_networkId_address ON Relay (networkId,address);
-
 CREATE TABLE Rule (
   networkId char(16) NOT NULL REFERENCES Network(id) ON DELETE CASCADE,
-  policyId varchar(32),
+  capId integer,
   ruleNo integer NOT NULL,
   ruleType integer NOT NULL DEFAULT(0),
   "addr" blob(16),
@@ -106,5 +98,15 @@ CREATE TABLE Rule (
   "int4" integer
 );
 
-CREATE INDEX Rule_networkId_ruleNo ON Rule (networkId, ruleNo);
-CREATE INDEX Rule_networkId_policyId ON Rule (networkId, policyId);
+CREATE INDEX Rule_networkId_capId ON Rule (networkId,capId);
+
+CREATE TABLE MemberTC (
+  networkId char(16) NOT NULL REFERENCES Network(id) ON DELETE CASCADE,
+  nodeId char(10) NOT NULL REFERENCES Node(id) ON DELETE CASCADE,
+  tagId integer,
+  tagValue integer,
+  capId integer,
+  capMaxCustodyChainLength integer NOT NULL DEFAULT(1)
+);
+
+CREATE INDEX MemberTC_networkId_nodeId ON MemberTC (networkId,nodeId);
diff --git a/ext/json/LICENSE.MIT b/ext/json/LICENSE.MIT
deleted file mode 100644
index e2ac4891..00000000
--- a/ext/json/LICENSE.MIT
+++ /dev/null
@@ -1,22 +0,0 @@
-The library is licensed under the MIT License 
-<http://opensource.org/licenses/MIT>:
-
-Copyright (c) 2013-2016 Niels Lohmann
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
diff --git a/ext/json/README.md b/ext/json/README.md
deleted file mode 100644
index c0bb61b1..00000000
--- a/ext/json/README.md
+++ /dev/null
@@ -1,511 +0,0 @@
-[![JSON for Modern C++](https://raw.githubusercontent.com/nlohmann/json/master/doc/json.gif)](https://github.com/nlohmann/json/releases)
-
-[![Build Status](https://travis-ci.org/nlohmann/json.svg?branch=master)](https://travis-ci.org/nlohmann/json)
-[![Build Status](https://ci.appveyor.com/api/projects/status/1acb366xfyg3qybk?svg=true)](https://ci.appveyor.com/project/nlohmann/json)
-[![Coverage Status](https://img.shields.io/coveralls/nlohmann/json.svg)](https://coveralls.io/r/nlohmann/json)
-[![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
-[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/p5o4znPnGHJpDVqN)
-[![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](http://nlohmann.github.io/json)
-[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
-[![Github Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
-[![Github Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](http://github.com/nlohmann/json/issues)
-
-## Design goals
-
-There are myriads of [JSON](http://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
-
-- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you know, what I mean.
-
-- **Trivial integration**. Our whole code consists of a single header file [`json.hpp`](https://github.com/nlohmann/json/blob/develop/src/json.hpp). That's it. No library, no subproject, no dependencies, no complex build system. The class is written in vanilla C++11. All in all, everything should require no adjustment of your compiler flags or project settings.
-
-- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/blob/master/test/src/unit.cpp) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) that there are no memory leaks.
-
-Other aspects were not so important to us:
-
-- **Memory efficiency**. Each JSON object has an overhead of one pointer (the maximal size of a union) and one enumeration element (1 byte). The default generalization uses the following C++ data types: `std::string` for strings, `int64_t`, `uint64_t` or `double` for numbers, `std::map` for objects, `std::vector` for arrays, and `bool` for Booleans. However, you can template the generalized class `basic_json` to your needs.
-
-- **Speed**. We currently implement the parser as naive [recursive descent parser](http://en.wikipedia.org/wiki/Recursive_descent_parser) with hand coded string handling. It is fast enough, but a [LALR-parser](http://en.wikipedia.org/wiki/LALR_parser) may be even faster (but would consist of more files which makes the integration harder).
-
-See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.github/CONTRIBUTING.md#please-dont) for more information.
-
-
-## Integration
-
-The single required source, file `json.hpp` is in the `src` directory or [released here](https://github.com/nlohmann/json/releases). All you need to do is add
-
-```cpp
-#include "json.hpp"
-
-// for convenience
-using json = nlohmann::json;
-```
-
-to the files you want to use JSON objects. That's it. Do not forget to set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).
-
-:beer: If you are using OS X and [Homebrew](http://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann_json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann_json --HEAD`.
-
-
-## Examples
-
-Here are some examples to give you an idea how to use the class.
-
-Assume you want to create the JSON object
-
-```json
-{
-  "pi": 3.141,
-  "happy": true,
-  "name": "Niels",
-  "nothing": null,
-  "answer": {
-    "everything": 42
-  },
-  "list": [1, 0, 2],
-  "object": {
-    "currency": "USD",
-    "value": 42.99
-  }
-}
-```
-
-With the JSON class, you could write:
-
-```cpp
-// create an empty structure (null)
-json j;
-
-// add a number that is stored as double (note the implicit conversion of j to an object)
-j["pi"] = 3.141;
-
-// add a Boolean that is stored as bool
-j["happy"] = true;
-
-// add a string that is stored as std::string
-j["name"] = "Niels";
-
-// add another null object by passing nullptr
-j["nothing"] = nullptr;
-
-// add an object inside the object
-j["answer"]["everything"] = 42;
-
-// add an array that is stored as std::vector (using an initializer list)
-j["list"] = { 1, 0, 2 };
-
-// add another object (using an initializer list of pairs)
-j["object"] = { {"currency", "USD"}, {"value", 42.99} };
-
-// instead, you could also write (which looks very similar to the JSON above)
-json j2 = {
-  {"pi", 3.141},
-  {"happy", true},
-  {"name", "Niels"},
-  {"nothing", nullptr},
-  {"answer", {
-    {"everything", 42}
-  }},
-  {"list", {1, 0, 2}},
-  {"object", {
-    {"currency", "USD"},
-    {"value", 42.99}
-  }}
-};
-```
-
-Note that in all these cases, you never need to "tell" the compiler which JSON value you want to use. If you want to be explicit or express some edge cases, the functions `json::array` and `json::object` will help:
-
-```cpp
-// a way to express the empty array []
-json empty_array_explicit = json::array();
-
-// ways to express the empty object {}
-json empty_object_implicit = json({});
-json empty_object_explicit = json::object();
-
-// a way to express an _array_ of key/value pairs [["currency", "USD"], ["value", 42.99]]
-json array_not_object = { json::array({"currency", "USD"}), json::array({"value", 42.99}) };
-```
-
-
-### Serialization / Deserialization
-
-You can create an object (deserialization) by appending `_json` to a string literal:
-
-```cpp
-// create object from string literal
-json j = "{ \"happy\": true, \"pi\": 3.141 }"_json;
-
-// or even nicer with a raw string literal
-auto j2 = R"(
-  {
-    "happy": true,
-    "pi": 3.141
-  }
-)"_json;
-
-// or explicitly
-auto j3 = json::parse("{ \"happy\": true, \"pi\": 3.141 }");
-```
-
-You can also get a string representation (serialize):
-
-```cpp
-// explicit conversion to string
-std::string s = j.dump();    // {\"happy\":true,\"pi\":3.141}
-
-// serialization with pretty printing
-// pass in the amount of spaces to indent
-std::cout << j.dump(4) << std::endl;
-// {
-//     "happy": true,
-//     "pi": 3.141
-// }
-```
-
-You can also use streams to serialize and deserialize:
-
-```cpp
-// deserialize from standard input
-json j;
-std::cin >> j;
-
-// serialize to standard output
-std::cout << j;
-
-// the setw manipulator was overloaded to set the indentation for pretty printing
-std::cout << std::setw(4) << j << std::endl;
-```
-
-These operators work for any subclasses of `std::istream` or `std::ostream`.
-
-Please note that setting the exception bit for `failbit` is inappropriate for this use case. It will result in program termination due to the `noexcept` specifier in use.
-
-
-### STL-like access
-
-We designed the JSON class to behave just like an STL container. In fact, it satisfies the [**ReversibleContainer**](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) requirement.
-
-```cpp
-// create an array using push_back
-json j;
-j.push_back("foo");
-j.push_back(1);
-j.push_back(true);
-
-// iterate the array
-for (json::iterator it = j.begin(); it != j.end(); ++it) {
-  std::cout << *it << '\n';
-}
-
-// range-based for
-for (auto& element : j) {
-  std::cout << element << '\n';
-}
-
-// getter/setter
-const std::string tmp = j[0];
-j[1] = 42;
-bool foo = j.at(2);
-
-// other stuff
-j.size();     // 3 entries
-j.empty();    // false
-j.type();     // json::value_t::array
-j.clear();    // the array is empty again
-
-// convenience type checkers
-j.is_null();
-j.is_boolean();
-j.is_number();
-j.is_object();
-j.is_array();
-j.is_string();
-
-// comparison
-j == "[\"foo\", 1, true]"_json;  // true
-
-// create an object
-json o;
-o["foo"] = 23;
-o["bar"] = false;
-o["baz"] = 3.141;
-
-// special iterator member functions for objects
-for (json::iterator it = o.begin(); it != o.end(); ++it) {
-  std::cout << it.key() << " : " << it.value() << "\n";
-}
-
-// find an entry
-if (o.find("foo") != o.end()) {
-  // there is an entry with key "foo"
-}
-
-// or simpler using count()
-int foo_present = o.count("foo"); // 1
-int fob_present = o.count("fob"); // 0
-
-// delete an entry
-o.erase("foo");
-```
-
-
-### Conversion from STL containers
-
-Any sequence container (`std::array`, `std::vector`, `std::deque`, `std::forward_list`, `std::list`) whose values can be used to construct JSON types (e.g., integers, floating point numbers, Booleans, string types, or again STL containers described in this section) can be used to create a JSON array. The same holds for similar associative containers (`std::set`, `std::multiset`, `std::unordered_set`, `std::unordered_multiset`), but in these cases the order of the elements of the array depends how the elements are ordered in the respective STL container.
-
-```cpp
-std::vector<int> c_vector {1, 2, 3, 4};
-json j_vec(c_vector);
-// [1, 2, 3, 4]
-
-std::deque<double> c_deque {1.2, 2.3, 3.4, 5.6};
-json j_deque(c_deque);
-// [1.2, 2.3, 3.4, 5.6]
-
-std::list<bool> c_list {true, true, false, true};
-json j_list(c_list);
-// [true, true, false, true]
-
-std::forward_list<int64_t> c_flist {12345678909876, 23456789098765, 34567890987654, 45678909876543};
-json j_flist(c_flist);
-// [12345678909876, 23456789098765, 34567890987654, 45678909876543]
-
-std::array<unsigned long, 4> c_array {{1, 2, 3, 4}};
-json j_array(c_array);
-// [1, 2, 3, 4]
-
-std::set<std::string> c_set {"one", "two", "three", "four", "one"};
-json j_set(c_set); // only one entry for "one" is used
-// ["four", "one", "three", "two"]
-
-std::unordered_set<std::string> c_uset {"one", "two", "three", "four", "one"};
-json j_uset(c_uset); // only one entry for "one" is used
-// maybe ["two", "three", "four", "one"]
-
-std::multiset<std::string> c_mset {"one", "two", "one", "four"};
-json j_mset(c_mset); // only one entry for "one" is used
-// maybe ["one", "two", "four"]
-
-std::unordered_multiset<std::string> c_umset {"one", "two", "one", "four"};
-json j_umset(c_umset); // both entries for "one" are used
-// maybe ["one", "two", "one", "four"]
-```
-
-Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON types (see examples above) can be used to to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
-
-```cpp
-std::map<std::string, int> c_map { {"one", 1}, {"two", 2}, {"three", 3} };
-json j_map(c_map);
-// {"one": 1, "three": 3, "two": 2 }
-
-std::unordered_map<const char*, double> c_umap { {"one", 1.2}, {"two", 2.3}, {"three", 3.4} };
-json j_umap(c_umap);
-// {"one": 1.2, "two": 2.3, "three": 3.4}
-
-std::multimap<std::string, bool> c_mmap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
-json j_mmap(c_mmap); // only one entry for key "three" is used
-// maybe {"one": true, "two": true, "three": true}
-
-std::unordered_multimap<std::string, bool> c_ummap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
-json j_ummap(c_ummap); // only one entry for key "three" is used
-// maybe {"one": true, "two": true, "three": true}
-```
-
-### JSON Pointer and JSON Patch
-
-The library supports **JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) as alternative means to address structured values. On top of this, **JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) allows to describe differences between two JSON values - effectively allowing patch and diff operations known from Unix.
-
-```cpp
-// a JSON value
-json j_original = R"({
-  "baz": ["one", "two", "three"],
-  "foo": "bar"
-})"_json;
-
-// access members with a JSON pointer (RFC 6901)
-j_original["/baz/1"_json_pointer];
-// "two"
-
-// a JSON patch (RFC 6902)
-json j_patch = R"([
-  { "op": "replace", "path": "/baz", "value": "boo" },
-  { "op": "add", "path": "/hello", "value": ["world"] },
-  { "op": "remove", "path": "/foo"}
-])"_json;
-
-// apply the patch
-json j_result = j_original.patch(j_patch);
-// {
-//    "baz": "boo",
-//    "hello": ["world"]
-// }
-
-// calculate a JSON patch from two JSON values
-json::diff(j_result, j_original);
-// [
-//   { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] },
-//   { "op": "remove","path": "/hello" },
-//   { "op": "add", "path": "/foo", "value": "bar" }
-// ]
-```
-
-
-### Implicit conversions
-
-The type of the JSON object is determined automatically by the expression to store. Likewise, the stored value is implicitly converted.
-
-```cpp
-// strings
-std::string s1 = "Hello, world!";
-json js = s1;
-std::string s2 = js;
-
-// Booleans
-bool b1 = true;
-json jb = b1;
-bool b2 = jb;
-
-// numbers
-int i = 42;
-json jn = i;
-double f = jn;
-
-// etc.
-```
-
-You can also explicitly ask for the value:
-
-```cpp
-std::string vs = js.get<std::string>();
-bool vb = jb.get<bool>();
-int vi = jn.get<int>();
-
-// etc.
-```
-
-
-## Supported compilers
-
-Though it's 2016 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
-
-- GCC 4.9 - 6.0 (and possibly later)
-- Clang 3.4 - 3.9 (and possibly later)
-- Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
-
-I would be happy to learn about other compilers/versions.
-
-Please note:
-
-- GCC 4.8 does not work because of two bugs ([55817](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55817) and [57824](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57824)) in the C++11 support. Note there is a [pull request](https://github.com/nlohmann/json/pull/212) to fix some of the issues.
-- Android defaults to using very old compilers and C++ libraries. To fix this, add the following to your `Application.mk`. This will switch to the LLVM C++ library, the Clang compiler, and enable C++11 and other features disabled by default.
- 
-    ```
-    APP_STL := c++_shared
-    NDK_TOOLCHAIN_VERSION := clang3.6
-    APP_CPPFLAGS += -frtti -fexceptions
-    ```
- 
-    The code compiles successfully with [Android NDK](https://developer.android.com/ndk/index.html?hl=ml), Revision 9 - 11 (and possibly later) and [CrystaX's Android NDK](https://www.crystax.net/en/android/ndk) version 10.
-
-- For GCC running on MinGW or Android SDK, the error `'to_string' is not a member of 'std'` (or similarly, for `strtod`) may occur. Note this is not an issue with the code,  but rather with the compiler itself. On Android, see above to build with a newer environment.  For MinGW, please refer to [this site](http://tehsausage.com/mingw-to-string) and [this discussion](https://github.com/nlohmann/json/issues/136) for information on how to fix this bug. For Android NDK using `APP_STL := gnustl_static`, please refer to [this discussion](https://github.com/nlohmann/json/issues/219).
-
-The following compilers are currently used in continuous integration at [Travis](https://travis-ci.org/nlohmann/json) and [AppVeyor](https://ci.appveyor.com/project/nlohmann/json):
-
-| Compiler        | Operating System             | Version String |
-|-----------------|------------------------------|----------------|
-| GCC 4.9.3       | Ubuntu 14.04.4 LTS           | g++-4.9 (Ubuntu 4.9.3-8ubuntu2~14.04) 4.9.3 |
-| GCC 5.3.0       | Ubuntu 14.04.4 LTS           | g++-5 (Ubuntu 5.3.0-3ubuntu1~14.04) 5.3.0 20151204 |
-| GCC 6.1.1       | Ubuntu 14.04.4 LTS           | g++-6 (Ubuntu 6.1.1-3ubuntu11~14.04.1) 6.1.1 20160511 |
-| Clang 3.8.0     | Ubuntu 14.04.4 LTS           | clang version 3.8.0 (tags/RELEASE_380/final) |
-| Clang Xcode 6.1 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) |
-| Clang Xcode 6.2 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) |
-| Clang Xcode 6.3 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn) |
-| Clang Xcode 6.4 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn) |
-| Clang Xcode 7.1 | Darwin Kernel Version 14.5.0 (OSX 10.10.5) | Apple LLVM version 7.0.0 (clang-700.1.76) |
-| Clang Xcode 7.2 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.0.2 (clang-700.1.81) |
-| Clang Xcode 7.3 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.3.0 (clang-703.0.29) |
-| Clang Xcode 8.0 | Darwin Kernel Version 15.5.0 (OSX 10.11.5) | Apple LLVM version 8.0.0 (clang-800.0.24.1) |
-| Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25123.0 | 
-
-
-## License
-
-<img align="right" src="http://opensource.org/trademarks/opensource/OSI-Approved-License-100x137.png">
-
-The class is licensed under the [MIT License](http://opensource.org/licenses/MIT):
-
-Copyright &copy; 2013-2016 [Niels Lohmann](http://nlohmann.me)
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-
-## Thanks
-
-I deeply appreciate the help of the following people.
-
-- [Teemperor](https://github.com/Teemperor) implemented CMake support and lcov integration, realized escape and Unicode handling in the string parser, and fixed the JSON serialization.
-- [elliotgoodrich](https://github.com/elliotgoodrich) fixed an issue with double deletion in the iterator classes.
-- [kirkshoop](https://github.com/kirkshoop) made the iterators of the class composable to other libraries.
-- [wancw](https://github.com/wanwc) fixed a bug that hindered the class to compile with Clang.
-- Tomas Åblad found a bug in the iterator implementation.
-- [Joshua C. Randall](https://github.com/jrandall) fixed a bug in the floating-point serialization.
-- [Aaron Burghardt](https://github.com/aburgh) implemented code to parse streams incrementally. Furthermore, he greatly improved the parser class by allowing the definition of a filter function to discard undesired elements while parsing.
-- [Daniel Kopeček](https://github.com/dkopecek) fixed a bug in the compilation with GCC 5.0.
-- [Florian Weber](https://github.com/Florianjw) fixed a bug in and improved the performance of the comparison operators.
-- [Eric Cornelius](https://github.com/EricMCornelius) pointed out a bug in the handling with NaN and infinity values. He also improved the performance of the string escaping.
-- [易思龙](https://github.com/likebeta) implemented a conversion from anonymous enums.
-- [kepkin](https://github.com/kepkin) patiently pushed forward the support for Microsoft Visual studio.
-- [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators and helped with numerous hints and improvements.
-- [Caio Luppi](https://github.com/caiovlp) fixed a bug in the Unicode handling.
-- [dariomt](https://github.com/dariomt) fixed some typos in the examples.
-- [Daniel Frey](https://github.com/d-frey) cleaned up some pointers and implemented exception-safe memory allocation.
-- [Colin Hirsch](https://github.com/ColinH) took care of a small namespace issue.
-- [Huu Nguyen](https://github.com/whoshuu) correct a variable name in the documentation.
-- [Silverweed](https://github.com/silverweed) overloaded `parse()` to accept an rvalue reference.
-- [dariomt](https://github.com/dariomt) fixed a subtlety in MSVC type support and implemented the `get_ref()` function to get a reference to stored values.
-- [ZahlGraf](https://github.com/ZahlGraf) added a workaround that allows compilation using Android NDK.
-- [whackashoe](https://github.com/whackashoe) replaced a function that was marked as unsafe by Visual Studio.
-- [406345](https://github.com/406345) fixed two small warnings.
-- [Glen Fernandes](https://github.com/glenfe) noted a potential portability problem in the `has_mapped_type` function.
-- [Corbin Hughes](https://github.com/nibroc) fixed some typos in the contribution guidelines.
-- [twelsby](https://github.com/twelsby) fixed the array subscript operator, an issue that failed the MSVC build, and floating-point parsing/dumping. He further added support for unsigned integer numbers and implemented better roundtrip support for parsed numbers.
-- [Volker Diels-Grabsch](https://github.com/vog) fixed a link in the README file.
-- [msm-](https://github.com/msm-) added support for american fuzzy lop. 
-- [Annihil](https://github.com/Annihil) fixed an example in the README file.
-- [Themercee](https://github.com/Themercee) noted a wrong URL in the README file.
-- [Lv Zheng](https://github.com/lv-zheng) fixed a namespace issue with `int64_t` and `uint64_t`.
-- [abc100m](https://github.com/abc100m) analyzed the issues with GCC 4.8 and proposed a [partial solution](https://github.com/nlohmann/json/pull/212).
-- [zewt](https://github.com/zewt) added useful notes to the README file about Android.
-- [Róbert Márki](https://github.com/robertmrk) added a fix to use move iterators and improved the integration via CMake.
-- [Chris Kitching](https://github.com/ChrisKitching) cleaned up the CMake files.
-- [Tom Needham](https://github.com/06needhamt) fixed a subtle bug with MSVC 2015 which was also proposed by [Michael K.](https://github.com/Epidal).
-- [Mário Feroldi](https://github.com/thelostt) fixed a small typo.
-- [duncanwerner](https://github.com/duncanwerner) found a really embarrassing performance regression in the 2.0.0 release.
-- [Damien](https://github.com/dtoma) fixed one of the last conversion warnings.
-
-Thanks a lot for helping out!
-
-
-## Notes
-
-- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](http://en.cppreference.com/w/cpp/error/assert).
-- As the exact type of a number is not defined in the [JSON specification](http://rfc7159.net/rfc7159), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
-
-
-## Execute unit tests
-
-To compile and run the tests, you need to execute
-
-```sh
-$ make
-$ ./json_unit "*"
-
-===============================================================================
-All tests passed (8905012 assertions in 32 test cases)
-```
-
-For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).
diff --git a/ext/json/json.hpp b/ext/json/json.hpp
deleted file mode 100644
index 878fb899..00000000
--- a/ext/json/json.hpp
+++ /dev/null
@@ -1,10435 +0,0 @@
-/*
-    __ _____ _____ _____
- __|  |   __|     |   | |  JSON for Modern C++
-|  |  |__   |  |  | | | |  version 2.0.2
-|_____|_____|_____|_|___|  https://github.com/nlohmann/json
-
-Licensed under the MIT License <http://opensource.org/licenses/MIT>.
-Copyright (c) 2013-2016 Niels Lohmann <http://nlohmann.me>.
-
-Permission is hereby  granted, free of charge, to any  person obtaining a copy
-of this software and associated  documentation files (the "Software"), to deal
-in the Software  without restriction, including without  limitation the rights
-to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
-copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
-IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
-FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
-AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
-LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
-*/
-
-#ifndef NLOHMANN_JSON_HPP
-#define NLOHMANN_JSON_HPP
-
-#include <algorithm>
-#include <array>
-#include <cassert>
-#include <ciso646>
-#include <cmath>
-#include <cstddef>
-#include <cstdint>
-#include <cstdlib>
-#include <functional>
-#include <initializer_list>
-#include <iomanip>
-#include <iostream>
-#include <iterator>
-#include <limits>
-#include <locale>
-#include <map>
-#include <memory>
-#include <numeric>
-#include <sstream>
-#include <stdexcept>
-#include <string>
-#include <type_traits>
-#include <utility>
-#include <vector>
-
-// exclude unsupported compilers
-#if defined(__clang__)
-    #define CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
-    #if CLANG_VERSION < 30400
-        #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
-    #endif
-#elif defined(__GNUC__)
-    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
-    #if GCC_VERSION < 40900
-        #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
-    #endif
-#endif
-
-// disable float-equal warnings on GCC/clang
-#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-    #pragma GCC diagnostic push
-    #pragma GCC diagnostic ignored "-Wfloat-equal"
-#endif
-
-/*!
-@brief namespace for Niels Lohmann
-@see https://github.com/nlohmann
-@since version 1.0.0
-*/
-namespace nlohmann
-{
-
-
-/*!
-@brief unnamed namespace with internal helper functions
-@since version 1.0.0
-*/
-namespace
-{
-/*!
-@brief Helper to determine whether there's a key_type for T.
-
-Thus helper is used to tell associative containers apart from other containers
-such as sequence containers. For instance, `std::map` passes the test as it
-contains a `mapped_type`, whereas `std::vector` fails the test.
-
-@sa http://stackoverflow.com/a/7728728/266378
-@since version 1.0.0
-*/
-template<typename T>
-struct has_mapped_type
-{
-  private:
-    template<typename C> static char test(typename C::mapped_type*);
-    template<typename C> static char (&test(...))[2];
-  public:
-    static constexpr bool value = sizeof(test<T>(0)) == 1;
-};
-
-/*!
-@brief helper class to create locales with decimal point
-
-This struct is used a default locale during the JSON serialization. JSON
-requires the decimal point to be `.`, so this function overloads the
-`do_decimal_point()` function to return `.`. This function is called by
-float-to-string conversions to retrieve the decimal separator between integer
-and fractional parts.
-
-@sa https://github.com/nlohmann/json/issues/51#issuecomment-86869315
-@since version 2.0.0
-*/
-struct DecimalSeparator : std::numpunct<char>
-{
-    char do_decimal_point() const
-    {
-        return '.';
-    }
-};
-
-}
-
-/*!
-@brief a class to store JSON values
-
-@tparam ObjectType type for JSON objects (`std::map` by default; will be used
-in @ref object_t)
-@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
-in @ref array_t)
-@tparam StringType type for JSON strings and object keys (`std::string` by
-default; will be used in @ref string_t)
-@tparam BooleanType type for JSON booleans (`bool` by default; will be used
-in @ref boolean_t)
-@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
-default; will be used in @ref number_integer_t)
-@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
-`uint64_t` by default; will be used in @ref number_unsigned_t)
-@tparam NumberFloatType type for JSON floating-point numbers (`double` by
-default; will be used in @ref number_float_t)
-@tparam AllocatorType type of the allocator to use (`std::allocator` by
-default)
-
-@requirement The class satisfies the following concept requirements:
-- Basic
- - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
-   JSON values can be default constructed. The result will be a JSON null value.
- - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
-   A JSON value can be constructed from an rvalue argument.
- - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
-   A JSON value can be copy-constructed from an lvalue expression.
- - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
-   A JSON value van be assigned from an rvalue argument.
- - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
-   A JSON value can be copy-assigned from an lvalue expression.
- - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
-   JSON values can be destructed.
-- Layout
- - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
-   JSON values have
-   [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
-   All non-static data members are private and standard layout types, the class
-   has no virtual functions or (virtual) base classes.
-- Library-wide
- - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
-   JSON values can be compared with `==`, see @ref
-   operator==(const_reference,const_reference).
- - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
-   JSON values can be compared with `<`, see @ref
-   operator<(const_reference,const_reference).
- - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
-   Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
-   other compatible types, using unqualified function call @ref swap().
- - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
-   JSON values can be compared against `std::nullptr_t` objects which are used
-   to model the `null` value.
-- Container
- - [Container](http://en.cppreference.com/w/cpp/concept/Container):
-   JSON values can be used like STL containers and provide iterator access.
- - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
-   JSON values can be used like STL containers and provide reverse iterator
-   access.
-
-@invariant The member variables @a m_value and @a m_type have the following
-relationship:
-- If `m_type == value_t::object`, then `m_value.object != nullptr`.
-- If `m_type == value_t::array`, then `m_value.array != nullptr`.
-- If `m_type == value_t::string`, then `m_value.string != nullptr`.
-The invariants are checked by member function assert_invariant().
-
-@internal
-@note ObjectType trick from http://stackoverflow.com/a/9860911
-@endinternal
-
-@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
-Format](http://rfc7159.net/rfc7159)
-
-@since version 1.0.0
-
-@nosubgrouping
-*/
-template <
-    template<typename U, typename V, typename... Args> class ObjectType = std::map,
-    template<typename U, typename... Args> class ArrayType = std::vector,
-    class StringType = std::string,
-    class BooleanType = bool,
-    class NumberIntegerType = std::int64_t,
-    class NumberUnsignedType = std::uint64_t,
-    class NumberFloatType = double,
-    template<typename U> class AllocatorType = std::allocator
-    >
-class basic_json
-{
-  private:
-    /// workaround type for MSVC
-    using basic_json_t = basic_json<ObjectType, ArrayType, StringType,
-          BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType,
-          AllocatorType>;
-
-  public:
-    // forward declarations
-    template<typename Base> class json_reverse_iterator;
-    class json_pointer;
-
-    /////////////////////
-    // container types //
-    /////////////////////
-
-    /// @name container types
-    /// The canonic container types to use @ref basic_json like any other STL
-    /// container.
-    /// @{
-
-    /// the type of elements in a basic_json container
-    using value_type = basic_json;
-
-    /// the type of an element reference
-    using reference = value_type&;
-    /// the type of an element const reference
-    using const_reference = const value_type&;
-
-    /// a type to represent differences between iterators
-    using difference_type = std::ptrdiff_t;
-    /// a type to represent container sizes
-    using size_type = std::size_t;
-
-    /// the allocator type
-    using allocator_type = AllocatorType<basic_json>;
-
-    /// the type of an element pointer
-    using pointer = typename std::allocator_traits<allocator_type>::pointer;
-    /// the type of an element const pointer
-    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
-
-    /// an iterator for a basic_json container
-    class iterator;
-    /// a const iterator for a basic_json container
-    class const_iterator;
-    /// a reverse iterator for a basic_json container
-    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
-    /// a const reverse iterator for a basic_json container
-    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;
-
-    /// @}
-
-
-    /*!
-    @brief returns the allocator associated with the container
-    */
-    static allocator_type get_allocator()
-    {
-        return allocator_type();
-    }
-
-
-    ///////////////////////////
-    // JSON value data types //
-    ///////////////////////////
-
-    /// @name JSON value data types
-    /// The data types to store a JSON value. These types are derived from
-    /// the template arguments passed to class @ref basic_json.
-    /// @{
-
-    /*!
-    @brief a type for an object
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
-    > An object is an unordered collection of zero or more name/value pairs,
-    > where a name is a string and a value is a string, number, boolean, null,
-    > object, or array.
-
-    To store objects in C++, a type is defined by the template parameters
-    described below.
-
-    @tparam ObjectType  the container to store objects (e.g., `std::map` or
-    `std::unordered_map`)
-    @tparam StringType the type of the keys or names (e.g., `std::string`).
-    The comparison function `std::less<StringType>` is used to order elements
-    inside the container.
-    @tparam AllocatorType the allocator to use for objects (e.g.,
-    `std::allocator`)
-
-    #### Default type
-
-    With the default values for @a ObjectType (`std::map`), @a StringType
-    (`std::string`), and @a AllocatorType (`std::allocator`), the default
-    value for @a object_t is:
-
-    @code {.cpp}
-    std::map<
-      std::string, // key_type
-      basic_json, // value_type
-      std::less<std::string>, // key_compare
-      std::allocator<std::pair<const std::string, basic_json>> // allocator_type
-    >
-    @endcode
-
-    #### Behavior
-
-    The choice of @a object_t influences the behavior of the JSON class. With
-    the default type, objects have the following behavior:
-
-    - When all names are unique, objects will be interoperable in the sense
-      that all software implementations receiving that object will agree on
-      the name-value mappings.
-    - When the names within an object are not unique, later stored name/value
-      pairs overwrite previously stored name/value pairs, leaving the used
-      names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will
-      be treated as equal and both stored as `{"key": 1}`.
-    - Internally, name/value pairs are stored in lexicographical order of the
-      names. Objects will also be serialized (see @ref dump) in this order.
-      For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored
-      and serialized as `{"a": 2, "b": 1}`.
-    - When comparing objects, the order of the name/value pairs is irrelevant.
-      This makes objects interoperable in the sense that they will not be
-      affected by these differences. For instance, `{"b": 1, "a": 2}` and
-      `{"a": 2, "b": 1}` will be treated as equal.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the maximum depth of nesting.
-
-    In this class, the object's limit of nesting is not constraint explicitly.
-    However, a maximum depth of nesting may be introduced by the compiler or
-    runtime environment. A theoretical limit can be queried by calling the
-    @ref max_size function of a JSON object.
-
-    #### Storage
-
-    Objects are stored as pointers in a @ref basic_json type. That is, for any
-    access to object values, a pointer of type `object_t*` must be
-    dereferenced.
-
-    @sa @ref array_t -- type for an array value
-
-    @since version 1.0.0
-
-    @note The order name/value pairs are added to the object is *not*
-    preserved by the library. Therefore, iterating an object may return
-    name/value pairs in a different order than they were originally stored. In
-    fact, keys will be traversed in alphabetical order as `std::map` with
-    `std::less` is used by default. Please note this behavior conforms to [RFC
-    7159](http://rfc7159.net/rfc7159), because any order implements the
-    specified "unordered" nature of JSON objects.
-    */
-    using object_t = ObjectType<StringType,
-          basic_json,
-          std::less<StringType>,
-          AllocatorType<std::pair<const StringType,
-          basic_json>>>;
-
-    /*!
-    @brief a type for an array
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
-    > An array is an ordered sequence of zero or more values.
-
-    To store objects in C++, a type is defined by the template parameters
-    explained below.
-
-    @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
-    `std::list`)
-    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
-
-    #### Default type
-
-    With the default values for @a ArrayType (`std::vector`) and @a
-    AllocatorType (`std::allocator`), the default value for @a array_t is:
-
-    @code {.cpp}
-    std::vector<
-      basic_json, // value_type
-      std::allocator<basic_json> // allocator_type
-    >
-    @endcode
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the maximum depth of nesting.
-
-    In this class, the array's limit of nesting is not constraint explicitly.
-    However, a maximum depth of nesting may be introduced by the compiler or
-    runtime environment. A theoretical limit can be queried by calling the
-    @ref max_size function of a JSON array.
-
-    #### Storage
-
-    Arrays are stored as pointers in a @ref basic_json type. That is, for any
-    access to array values, a pointer of type `array_t*` must be dereferenced.
-
-    @sa @ref object_t -- type for an object value
-
-    @since version 1.0.0
-    */
-    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
-
-    /*!
-    @brief a type for a string
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
-    > A string is a sequence of zero or more Unicode characters.
-
-    To store objects in C++, a type is defined by the template parameter
-    described below. Unicode values are split by the JSON class into
-    byte-sized characters during deserialization.
-
-    @tparam StringType  the container to store strings (e.g., `std::string`).
-    Note this container is used for keys/names in objects, see @ref object_t.
-
-    #### Default type
-
-    With the default values for @a StringType (`std::string`), the default
-    value for @a string_t is:
-
-    @code {.cpp}
-    std::string
-    @endcode
-
-    #### String comparison
-
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
-    > Software implementations are typically required to test names of object
-    > members for equality. Implementations that transform the textual
-    > representation into sequences of Unicode code units and then perform the
-    > comparison numerically, code unit by code unit, are interoperable in the
-    > sense that implementations will agree in all cases on equality or
-    > inequality of two strings. For example, implementations that compare
-    > strings with escaped characters unconverted may incorrectly find that
-    > `"a\\b"` and `"a\u005Cb"` are not equal.
-
-    This implementation is interoperable as it does compare strings code unit
-    by code unit.
-
-    #### Storage
-
-    String values are stored as pointers in a @ref basic_json type. That is,
-    for any access to string values, a pointer of type `string_t*` must be
-    dereferenced.
-
-    @since version 1.0.0
-    */
-    using string_t = StringType;
-
-    /*!
-    @brief a type for a boolean
-
-    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
-    type which differentiates the two literals `true` and `false`.
-
-    To store objects in C++, a type is defined by the template parameter @a
-    BooleanType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a BooleanType (`bool`), the default value for
-    @a boolean_t is:
-
-    @code {.cpp}
-    bool
-    @endcode
-
-    #### Storage
-
-    Boolean values are stored directly inside a @ref basic_json type.
-
-    @since version 1.0.0
-    */
-    using boolean_t = BooleanType;
-
-    /*!
-    @brief a type for a number (integer)
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
-
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
-
-    To store integer numbers in C++, a type is defined by the template
-    parameter @a NumberIntegerType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a NumberIntegerType (`int64_t`), the default
-    value for @a number_integer_t is:
-
-    @code {.cpp}
-    int64_t
-    @endcode
-
-    #### Default behavior
-
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in integer literals lead to an interpretation as octal
-      number. Internally, the value will be stored as decimal number. For
-      instance, the C++ integer literal `010` will be serialized to `8`.
-      During deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the range and precision of numbers.
-
-    When the default type is used, the maximal integer number that can be
-    stored is `9223372036854775807` (INT64_MAX) and the minimal integer number
-    that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers
-    that are out of range will yield over/underflow when used in a
-    constructor. During deserialization, too large or small integer numbers
-    will be automatically be stored as @ref number_unsigned_t or @ref
-    number_float_t.
-
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
-    > Note that when such software is used, numbers that are integers and are
-    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
-    > that implementations will agree exactly on their numeric values.
-
-    As this range is a subrange of the exactly supported range [INT64_MIN,
-    INT64_MAX], this class's integer type is interoperable.
-
-    #### Storage
-
-    Integer number values are stored directly inside a @ref basic_json type.
-
-    @sa @ref number_float_t -- type for number values (floating-point)
-
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
-
-    @since version 1.0.0
-    */
-    using number_integer_t = NumberIntegerType;
-
-    /*!
-    @brief a type for a number (unsigned)
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
-
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
-
-    To store unsigned integer numbers in C++, a type is defined by the
-    template parameter @a NumberUnsignedType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a NumberUnsignedType (`uint64_t`), the
-    default value for @a number_unsigned_t is:
-
-    @code {.cpp}
-    uint64_t
-    @endcode
-
-    #### Default behavior
-
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in integer literals lead to an interpretation as octal
-      number. Internally, the value will be stored as decimal number. For
-      instance, the C++ integer literal `010` will be serialized to `8`.
-      During deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the range and precision of numbers.
-
-    When the default type is used, the maximal integer number that can be
-    stored is `18446744073709551615` (UINT64_MAX) and the minimal integer
-    number that can be stored is `0`. Integer numbers that are out of range
-    will yield over/underflow when used in a constructor. During
-    deserialization, too large or small integer numbers will be automatically
-    be stored as @ref number_integer_t or @ref number_float_t.
-
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
-    > Note that when such software is used, numbers that are integers and are
-    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
-    > that implementations will agree exactly on their numeric values.
-
-    As this range is a subrange (when considered in conjunction with the
-    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
-    this class's integer type is interoperable.
-
-    #### Storage
-
-    Integer number values are stored directly inside a @ref basic_json type.
-
-    @sa @ref number_float_t -- type for number values (floating-point)
-    @sa @ref number_integer_t -- type for number values (integer)
-
-    @since version 2.0.0
-    */
-    using number_unsigned_t = NumberUnsignedType;
-
-    /*!
-    @brief a type for a number (floating-point)
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
-
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
-
-    To store floating-point numbers in C++, a type is defined by the template
-    parameter @a NumberFloatType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a NumberFloatType (`double`), the default
-    value for @a number_float_t is:
-
-    @code {.cpp}
-    double
-    @endcode
-
-    #### Default behavior
-
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in floating-point literals will be ignored. Internally,
-      the value will be stored as decimal number. For instance, the C++
-      floating-point literal `01.2` will be serialized to `1.2`. During
-      deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
-    > This specification allows implementations to set limits on the range and
-    > precision of numbers accepted. Since software that implements IEEE
-    > 754-2008 binary64 (double precision) numbers is generally available and
-    > widely used, good interoperability can be achieved by implementations
-    > that expect no more precision or range than these provide, in the sense
-    > that implementations will approximate JSON numbers within the expected
-    > precision.
-
-    This implementation does exactly follow this approach, as it uses double
-    precision floating-point numbers. Note values smaller than
-    `-1.79769313486232e+308` and values greater than `1.79769313486232e+308`
-    will be stored as NaN internally and be serialized to `null`.
-
-    #### Storage
-
-    Floating-point number values are stored directly inside a @ref basic_json
-    type.
-
-    @sa @ref number_integer_t -- type for number values (integer)
-
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
-
-    @since version 1.0.0
-    */
-    using number_float_t = NumberFloatType;
-
-    /// @}
-
-
-    ///////////////////////////
-    // JSON type enumeration //
-    ///////////////////////////
-
-    /*!
-    @brief the JSON type enumeration
-
-    This enumeration collects the different JSON types. It is internally used
-    to distinguish the stored values, and the functions @ref is_null(), @ref
-    is_object(), @ref is_array(), @ref is_string(), @ref is_boolean(), @ref
-    is_number() (with @ref is_number_integer(), @ref is_number_unsigned(), and
-    @ref is_number_float()), @ref is_discarded(), @ref is_primitive(), and
-    @ref is_structured() rely on it.
-
-    @note There are three enumeration entries (number_integer,
-    number_unsigned, and number_float), because the library distinguishes
-    these three types for numbers: @ref number_unsigned_t is used for unsigned
-    integers, @ref number_integer_t is used for signed integers, and @ref
-    number_float_t is used for floating-point numbers or to approximate
-    integers which do not fit in the limits of their respective type.
-
-    @sa @ref basic_json(const value_t value_type) -- create a JSON value with
-    the default value for a given type
-
-    @since version 1.0.0
-    */
-    enum class value_t : uint8_t
-    {
-        null,            ///< null value
-        object,          ///< object (unordered set of name/value pairs)
-        array,           ///< array (ordered collection of values)
-        string,          ///< string value
-        boolean,         ///< boolean value
-        number_integer,  ///< number value (signed integer)
-        number_unsigned, ///< number value (unsigned integer)
-        number_float,    ///< number value (floating-point)
-        discarded        ///< discarded by the the parser callback function
-    };
-
-
-  private:
-
-    /// helper for exception-safe object creation
-    template<typename T, typename... Args>
-    static T* create(Args&& ... args)
-    {
-        AllocatorType<T> alloc;
-        auto deleter = [&](T * object)
-        {
-            alloc.deallocate(object, 1);
-        };
-        std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
-        alloc.construct(object.get(), std::forward<Args>(args)...);
-        assert(object.get() != nullptr);
-        return object.release();
-    }
-
-    ////////////////////////
-    // JSON value storage //
-    ////////////////////////
-
-    /*!
-    @brief a JSON value
-
-    The actual storage for a JSON value of the @ref basic_json class. This
-    union combines the different storage types for the JSON value types
-    defined in @ref value_t.
-
-    JSON type | value_t type    | used type
-    --------- | --------------- | ------------------------
-    object    | object          | pointer to @ref object_t
-    array     | array           | pointer to @ref array_t
-    string    | string          | pointer to @ref string_t
-    boolean   | boolean         | @ref boolean_t
-    number    | number_integer  | @ref number_integer_t
-    number    | number_unsigned | @ref number_unsigned_t
-    number    | number_float    | @ref number_float_t
-    null      | null            | *no value is stored*
-
-    @note Variable-length types (objects, arrays, and strings) are stored as
-    pointers. The size of the union should not exceed 64 bits if the default
-    value types are used.
-
-    @since version 1.0.0
-    */
-    union json_value
-    {
-        /// object (stored with pointer to save storage)
-        object_t* object;
-        /// array (stored with pointer to save storage)
-        array_t* array;
-        /// string (stored with pointer to save storage)
-        string_t* string;
-        /// boolean
-        boolean_t boolean;
-        /// number (integer)
-        number_integer_t number_integer;
-        /// number (unsigned integer)
-        number_unsigned_t number_unsigned;
-        /// number (floating-point)
-        number_float_t number_float;
-
-        /// default constructor (for null values)
-        json_value() = default;
-        /// constructor for booleans
-        json_value(boolean_t v) noexcept : boolean(v) {}
-        /// constructor for numbers (integer)
-        json_value(number_integer_t v) noexcept : number_integer(v) {}
-        /// constructor for numbers (unsigned)
-        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
-        /// constructor for numbers (floating-point)
-        json_value(number_float_t v) noexcept : number_float(v) {}
-        /// constructor for empty values of a given type
-        json_value(value_t t)
-        {
-            switch (t)
-            {
-                case value_t::object:
-                {
-                    object = create<object_t>();
-                    break;
-                }
-
-                case value_t::array:
-                {
-                    array = create<array_t>();
-                    break;
-                }
-
-                case value_t::string:
-                {
-                    string = create<string_t>("");
-                    break;
-                }
-
-                case value_t::boolean:
-                {
-                    boolean = boolean_t(false);
-                    break;
-                }
-
-                case value_t::number_integer:
-                {
-                    number_integer = number_integer_t(0);
-                    break;
-                }
-
-                case value_t::number_unsigned:
-                {
-                    number_unsigned = number_unsigned_t(0);
-                    break;
-                }
-
-                case value_t::number_float:
-                {
-                    number_float = number_float_t(0.0);
-                    break;
-                }
-
-                default:
-                {
-                    break;
-                }
-            }
-        }
-
-        /// constructor for strings
-        json_value(const string_t& value)
-        {
-            string = create<string_t>(value);
-        }
-
-        /// constructor for objects
-        json_value(const object_t& value)
-        {
-            object = create<object_t>(value);
-        }
-
-        /// constructor for arrays
-        json_value(const array_t& value)
-        {
-            array = create<array_t>(value);
-        }
-    };
-
-    /*!
-    @brief checks the class invariants
-
-    This function asserts the class invariants. It needs to be called at the
-    end of every constructor to make sure that created objects respect the
-    invariant. Furthermore, it has to be called each time the type of a JSON
-    value is changed, because the invariant expresses a relationship between
-    @a m_type and @a m_value.
-    */
-    void assert_invariant() const
-    {
-        assert(m_type != value_t::object or m_value.object != nullptr);
-        assert(m_type != value_t::array or m_value.array != nullptr);
-        assert(m_type != value_t::string or m_value.string != nullptr);
-    }
-
-  public:
-    //////////////////////////
-    // JSON parser callback //
-    //////////////////////////
-
-    /*!
-    @brief JSON callback events
-
-    This enumeration lists the parser events that can trigger calling a
-    callback function of type @ref parser_callback_t during parsing.
-
-    @image html callback_events.png "Example when certain parse events are triggered"
-
-    @since version 1.0.0
-    */
-    enum class parse_event_t : uint8_t
-    {
-        /// the parser read `{` and started to process a JSON object
-        object_start,
-        /// the parser read `}` and finished processing a JSON object
-        object_end,
-        /// the parser read `[` and started to process a JSON array
-        array_start,
-        /// the parser read `]` and finished processing a JSON array
-        array_end,
-        /// the parser read a key of a value in an object
-        key,
-        /// the parser finished reading a JSON value
-        value
-    };
-
-    /*!
-    @brief per-element parser callback type
-
-    With a parser callback function, the result of parsing a JSON text can be
-    influenced. When passed to @ref parse(std::istream&, const
-    parser_callback_t) or @ref parse(const string_t&, const parser_callback_t),
-    it is called on certain events (passed as @ref parse_event_t via parameter
-    @a event) with a set recursion depth @a depth and context JSON value
-    @a parsed. The return value of the callback function is a boolean
-    indicating whether the element that emitted the callback shall be kept or
-    not.
-
-    We distinguish six scenarios (determined by the event type) in which the
-    callback function can be called. The following table describes the values
-    of the parameters @a depth, @a event, and @a parsed.
-
-    parameter @a event | description | parameter @a depth | parameter @a parsed
-    ------------------ | ----------- | ------------------ | -------------------
-    parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded
-    parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key
-    parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object
-    parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded
-    parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
-    parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
-
-    @image html callback_events.png "Example when certain parse events are triggered"
-
-    Discarding a value (i.e., returning `false`) has different effects
-    depending on the context in which function was called:
-
-    - Discarded values in structured types are skipped. That is, the parser
-      will behave as if the discarded value was never read.
-    - In case a value outside a structured type is skipped, it is replaced
-      with `null`. This case happens if the top-level element is skipped.
-
-    @param[in] depth  the depth of the recursion during parsing
-
-    @param[in] event  an event of type parse_event_t indicating the context in
-    the callback function has been called
-
-    @param[in,out] parsed  the current intermediate parse result; note that
-    writing to this value has no effect for parse_event_t::key events
-
-    @return Whether the JSON value which called the function during parsing
-    should be kept (`true`) or not (`false`). In the latter case, it is either
-    skipped completely or replaced by an empty discarded object.
-
-    @sa @ref parse(std::istream&, parser_callback_t) or
-    @ref parse(const string_t&, parser_callback_t) for examples
-
-    @since version 1.0.0
-    */
-    using parser_callback_t = std::function<bool(int depth,
-                              parse_event_t event,
-                              basic_json& parsed)>;
-
-
-    //////////////////
-    // constructors //
-    //////////////////
-
-    /// @name constructors and destructors
-    /// Constructors of class @ref basic_json, copy/move constructor, copy
-    /// assignment, static functions creating objects, and the destructor.
-    /// @{
-
-    /*!
-    @brief create an empty value with a given type
-
-    Create an empty JSON value with a given type. The value will be default
-    initialized with an empty value which depends on the type:
-
-    Value type  | initial value
-    ----------- | -------------
-    null        | `null`
-    boolean     | `false`
-    string      | `""`
-    number      | `0`
-    object      | `{}`
-    array       | `[]`
-
-    @param[in] value_type  the type of the value to create
-
-    @complexity Constant.
-
-    @throw std::bad_alloc if allocation for object, array, or string value
-    fails
-
-    @liveexample{The following code shows the constructor for different @ref
-    value_t values,basic_json__value_t}
-
-    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
-    @sa @ref basic_json(boolean_t value) -- create a boolean value
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const object_t&) -- create a object value
-    @sa @ref basic_json(const array_t&) -- create a array value
-    @sa @ref basic_json(const number_float_t) -- create a number
-    (floating-point) value
-    @sa @ref basic_json(const number_integer_t) -- create a number (integer)
-    value
-    @sa @ref basic_json(const number_unsigned_t) -- create a number (unsigned)
-    value
-
-    @since version 1.0.0
-    */
-    basic_json(const value_t value_type)
-        : m_type(value_type), m_value(value_type)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a null object (implicitly)
-
-    Create a `null` JSON value. This is the implicit version of the `null`
-    value constructor as it takes no parameters.
-
-    @note The class invariant is satisfied, because it poses no requirements
-    for null values.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this constructor never throws
-    exceptions.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - As postcondition, it holds: `basic_json().empty() == true`.
-
-    @liveexample{The following code shows the constructor for a `null` JSON
-    value.,basic_json}
-
-    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
-
-    @since version 1.0.0
-    */
-    basic_json() = default;
-
-    /*!
-    @brief create a null object (explicitly)
-
-    Create a `null` JSON value. This is the explicitly version of the `null`
-    value constructor as it takes a null pointer as parameter. It allows to
-    create `null` values by explicitly assigning a `nullptr` to a JSON value.
-    The passed null pointer itself is not read -- it is only used to choose
-    the right constructor.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this constructor never throws
-    exceptions.
-
-    @liveexample{The following code shows the constructor with null pointer
-    parameter.,basic_json__nullptr_t}
-
-    @sa @ref basic_json() -- default constructor (implicitly creating a `null`
-    value)
-
-    @since version 1.0.0
-    */
-    basic_json(std::nullptr_t) noexcept
-        : basic_json(value_t::null)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an object (explicit)
-
-    Create an object JSON value with a given content.
-
-    @param[in] val  a value for the object
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for object value fails
-
-    @liveexample{The following code shows the constructor with an @ref
-    object_t parameter.,basic_json__object_t}
-
-    @sa @ref basic_json(const CompatibleObjectType&) -- create an object value
-    from a compatible STL container
-
-    @since version 1.0.0
-    */
-    basic_json(const object_t& val)
-        : m_type(value_t::object), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an object (implicit)
-
-    Create an object JSON value with a given content. This constructor allows
-    any type @a CompatibleObjectType that can be used to construct values of
-    type @ref object_t.
-
-    @tparam CompatibleObjectType An object type whose `key_type` and
-    `value_type` is compatible to @ref object_t. Examples include `std::map`,
-    `std::unordered_map`, `std::multimap`, and `std::unordered_multimap` with
-    a `key_type` of `std::string`, and a `value_type` from which a @ref
-    basic_json value can be constructed.
-
-    @param[in] val  a value for the object
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for object value fails
-
-    @liveexample{The following code shows the constructor with several
-    compatible object type parameters.,basic_json__CompatibleObjectType}
-
-    @sa @ref basic_json(const object_t&) -- create an object value
-
-    @since version 1.0.0
-    */
-    template <class CompatibleObjectType, typename
-              std::enable_if<
-                  std::is_constructible<typename object_t::key_type, typename CompatibleObjectType::key_type>::value and
-                  std::is_constructible<basic_json, typename CompatibleObjectType::mapped_type>::value, int>::type
-              = 0>
-    basic_json(const CompatibleObjectType& val)
-        : m_type(value_t::object)
-    {
-        using std::begin;
-        using std::end;
-        m_value.object = create<object_t>(begin(val), end(val));
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an array (explicit)
-
-    Create an array JSON value with a given content.
-
-    @param[in] val  a value for the array
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for array value fails
-
-    @liveexample{The following code shows the constructor with an @ref array_t
-    parameter.,basic_json__array_t}
-
-    @sa @ref basic_json(const CompatibleArrayType&) -- create an array value
-    from a compatible STL containers
-
-    @since version 1.0.0
-    */
-    basic_json(const array_t& val)
-        : m_type(value_t::array), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an array (implicit)
-
-    Create an array JSON value with a given content. This constructor allows
-    any type @a CompatibleArrayType that can be used to construct values of
-    type @ref array_t.
-
-    @tparam CompatibleArrayType An object type whose `value_type` is
-    compatible to @ref array_t. Examples include `std::vector`, `std::deque`,
-    `std::list`, `std::forward_list`, `std::array`, `std::set`,
-    `std::unordered_set`, `std::multiset`, and `unordered_multiset` with a
-    `value_type` from which a @ref basic_json value can be constructed.
-
-    @param[in] val  a value for the array
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for array value fails
-
-    @liveexample{The following code shows the constructor with several
-    compatible array type parameters.,basic_json__CompatibleArrayType}
-
-    @sa @ref basic_json(const array_t&) -- create an array value
-
-    @since version 1.0.0
-    */
-    template <class CompatibleArrayType, typename
-              std::enable_if<
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::reverse_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_reverse_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename array_t::iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename array_t::const_iterator>::value and
-                  std::is_constructible<basic_json, typename CompatibleArrayType::value_type>::value, int>::type
-              = 0>
-    basic_json(const CompatibleArrayType& val)
-        : m_type(value_t::array)
-    {
-        using std::begin;
-        using std::end;
-        m_value.array = create<array_t>(begin(val), end(val));
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a string (explicit)
-
-    Create an string JSON value with a given content.
-
-    @param[in] val  a value for the string
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for string value fails
-
-    @liveexample{The following code shows the constructor with an @ref
-    string_t parameter.,basic_json__string_t}
-
-    @sa @ref basic_json(const typename string_t::value_type*) -- create a
-    string value from a character pointer
-    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
-    from a compatible string container
-
-    @since version 1.0.0
-    */
-    basic_json(const string_t& val)
-        : m_type(value_t::string), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a string (explicit)
-
-    Create a string JSON value with a given content.
-
-    @param[in] val  a literal value for the string
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for string value fails
-
-    @liveexample{The following code shows the constructor with string literal
-    parameter.,basic_json__string_t_value_type}
-
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
-    from a compatible string container
-
-    @since version 1.0.0
-    */
-    basic_json(const typename string_t::value_type* val)
-        : basic_json(string_t(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a string (implicit)
-
-    Create a string JSON value with a given content.
-
-    @param[in] val  a value for the string
-
-    @tparam CompatibleStringType an string type which is compatible to @ref
-    string_t, for instance `std::string`.
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for string value fails
-
-    @liveexample{The following code shows the construction of a string value
-    from a compatible type.,basic_json__CompatibleStringType}
-
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const typename string_t::value_type*) -- create a
-    string value from a character pointer
-
-    @since version 1.0.0
-    */
-    template <class CompatibleStringType, typename
-              std::enable_if<
-                  std::is_constructible<string_t, CompatibleStringType>::value, int>::type
-              = 0>
-    basic_json(const CompatibleStringType& val)
-        : basic_json(string_t(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a boolean (explicit)
-
-    Creates a JSON boolean type from a given value.
-
-    @param[in] val  a boolean value to store
-
-    @complexity Constant.
-
-    @liveexample{The example below demonstrates boolean
-    values.,basic_json__boolean_t}
-
-    @since version 1.0.0
-    */
-    basic_json(boolean_t val) noexcept
-        : m_type(value_t::boolean), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an integer number (explicit)
-
-    Create an integer number JSON value with a given content.
-
-    @tparam T A helper type to remove this function via SFINAE in case @ref
-    number_integer_t is the same as `int`. In this case, this constructor
-    would have the same signature as @ref basic_json(const int value). Note
-    the helper type @a T is not visible in this constructor's interface.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @complexity Constant.
-
-    @liveexample{The example below shows the construction of an integer
-    number value.,basic_json__number_integer_t}
-
-    @sa @ref basic_json(const int) -- create a number value (integer)
-    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
-    value (integer) from a compatible number type
-
-    @since version 1.0.0
-    */
-    template<typename T,
-             typename std::enable_if<
-                 not (std::is_same<T, int>::value)
-                 and std::is_same<T, number_integer_t>::value
-                 , int>::type
-             = 0>
-    basic_json(const number_integer_t val) noexcept
-        : m_type(value_t::number_integer), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an integer number from an enum type (explicit)
-
-    Create an integer number JSON value with a given content.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @note This constructor allows to pass enums directly to a constructor. As
-    C++ has no way of specifying the type of an anonymous enum explicitly, we
-    can only rely on the fact that such values implicitly convert to int. As
-    int may already be the same type of number_integer_t, we may need to
-    switch off the constructor @ref basic_json(const number_integer_t).
-
-    @complexity Constant.
-
-    @liveexample{The example below shows the construction of an integer
-    number value from an anonymous enum.,basic_json__const_int}
-
-    @sa @ref basic_json(const number_integer_t) -- create a number value
-    (integer)
-    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
-    value (integer) from a compatible number type
-
-    @since version 1.0.0
-    */
-    basic_json(const int val) noexcept
-        : m_type(value_t::number_integer),
-          m_value(static_cast<number_integer_t>(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an integer number (implicit)
-
-    Create an integer number JSON value with a given content. This constructor
-    allows any type @a CompatibleNumberIntegerType that can be used to
-    construct values of type @ref number_integer_t.
-
-    @tparam CompatibleNumberIntegerType An integer type which is compatible to
-    @ref number_integer_t. Examples include the types `int`, `int32_t`,
-    `long`, and `short`.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @complexity Constant.
-
-    @liveexample{The example below shows the construction of several integer
-    number values from compatible
-    types.,basic_json__CompatibleIntegerNumberType}
-
-    @sa @ref basic_json(const number_integer_t) -- create a number value
-    (integer)
-    @sa @ref basic_json(const int) -- create a number value (integer)
-
-    @since version 1.0.0
-    */
-    template<typename CompatibleNumberIntegerType, typename
-             std::enable_if<
-                 std::is_constructible<number_integer_t, CompatibleNumberIntegerType>::value and
-                 std::numeric_limits<CompatibleNumberIntegerType>::is_integer and
-                 std::numeric_limits<CompatibleNumberIntegerType>::is_signed,
-                 CompatibleNumberIntegerType>::type
-             = 0>
-    basic_json(const CompatibleNumberIntegerType val) noexcept
-        : m_type(value_t::number_integer),
-          m_value(static_cast<number_integer_t>(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an unsigned integer number (explicit)
-
-    Create an unsigned integer number JSON value with a given content.
-
-    @tparam T  helper type to compare number_unsigned_t and unsigned int (not
-    visible in) the interface.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @complexity Constant.
-
-    @sa @ref basic_json(const CompatibleNumberUnsignedType) -- create a number
-    value (unsigned integer) from a compatible number type
-
-    @since version 2.0.0
-    */
-    template<typename T,
-             typename std::enable_if<
-                 not (std::is_same<T, int>::value)
-                 and std::is_same<T, number_unsigned_t>::value
-                 , int>::type
-             = 0>
-    basic_json(const number_unsigned_t val) noexcept
-        : m_type(value_t::number_unsigned), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an unsigned number (implicit)
-
-    Create an unsigned number JSON value with a given content. This
-    constructor allows any type @a CompatibleNumberUnsignedType that can be
-    used to construct values of type @ref number_unsigned_t.
-
-    @tparam CompatibleNumberUnsignedType An integer type which is compatible
-    to @ref number_unsigned_t. Examples may include the types `unsigned int`,
-    `uint32_t`, or `unsigned short`.
-
-    @param[in] val  an unsigned integer to create a JSON number from
-
-    @complexity Constant.
-
-    @sa @ref basic_json(const number_unsigned_t) -- create a number value
-    (unsigned)
-
-    @since version 2.0.0
-    */
-    template <typename CompatibleNumberUnsignedType, typename
-              std::enable_if <
-                  std::is_constructible<number_unsigned_t, CompatibleNumberUnsignedType>::value and
-                  std::numeric_limits<CompatibleNumberUnsignedType>::is_integer and
-                  not std::numeric_limits<CompatibleNumberUnsignedType>::is_signed,
-                  CompatibleNumberUnsignedType>::type
-              = 0>
-    basic_json(const CompatibleNumberUnsignedType val) noexcept
-        : m_type(value_t::number_unsigned),
-          m_value(static_cast<number_unsigned_t>(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a floating-point number (explicit)
-
-    Create a floating-point number JSON value with a given content.
-
-    @param[in] val  a floating-point value to create a JSON number from
-
-    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
-    disallows NaN values:
-    > Numeric values that cannot be represented in the grammar below (such as
-    > Infinity and NaN) are not permitted.
-    In case the parameter @a val is not a number, a JSON null value is created
-    instead.
-
-    @complexity Constant.
-
-    @liveexample{The following example creates several floating-point
-    values.,basic_json__number_float_t}
-
-    @sa @ref basic_json(const CompatibleNumberFloatType) -- create a number
-    value (floating-point) from a compatible number type
-
-    @since version 1.0.0
-    */
-    basic_json(const number_float_t val) noexcept
-        : m_type(value_t::number_float), m_value(val)
-    {
-        // replace infinity and NAN by null
-        if (not std::isfinite(val))
-        {
-            m_type = value_t::null;
-            m_value = json_value();
-        }
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an floating-point number (implicit)
-
-    Create an floating-point number JSON value with a given content. This
-    constructor allows any type @a CompatibleNumberFloatType that can be used
-    to construct values of type @ref number_float_t.
-
-    @tparam CompatibleNumberFloatType A floating-point type which is
-    compatible to @ref number_float_t. Examples may include the types `float`
-    or `double`.
-
-    @param[in] val  a floating-point to create a JSON number from
-
-    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
-    disallows NaN values:
-    > Numeric values that cannot be represented in the grammar below (such as
-    > Infinity and NaN) are not permitted.
-    In case the parameter @a val is not a number, a JSON null value is
-    created instead.
-
-    @complexity Constant.
-
-    @liveexample{The example below shows the construction of several
-    floating-point number values from compatible
-    types.,basic_json__CompatibleNumberFloatType}
-
-    @sa @ref basic_json(const number_float_t) -- create a number value
-    (floating-point)
-
-    @since version 1.0.0
-    */
-    template<typename CompatibleNumberFloatType, typename = typename
-             std::enable_if<
-                 std::is_constructible<number_float_t, CompatibleNumberFloatType>::value and
-                 std::is_floating_point<CompatibleNumberFloatType>::value>::type
-             >
-    basic_json(const CompatibleNumberFloatType val) noexcept
-        : basic_json(number_float_t(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a container (array or object) from an initializer list
-
-    Creates a JSON value of type array or object from the passed initializer
-    list @a init. In case @a type_deduction is `true` (default), the type of
-    the JSON value to be created is deducted from the initializer list @a init
-    according to the following rules:
-
-    1. If the list is empty, an empty JSON object value `{}` is created.
-    2. If the list consists of pairs whose first element is a string, a JSON
-       object value is created where the first elements of the pairs are
-       treated as keys and the second elements are as values.
-    3. In all other cases, an array is created.
-
-    The rules aim to create the best fit between a C++ initializer list and
-    JSON values. The rationale is as follows:
-
-    1. The empty initializer list is written as `{}` which is exactly an empty
-       JSON object.
-    2. C++ has now way of describing mapped types other than to list a list of
-       pairs. As JSON requires that keys must be of type string, rule 2 is the
-       weakest constraint one can pose on initializer lists to interpret them
-       as an object.
-    3. In all other cases, the initializer list could not be interpreted as
-       JSON object type, so interpreting it as JSON array type is safe.
-
-    With the rules described above, the following JSON values cannot be
-    expressed by an initializer list:
-
-    - the empty array (`[]`): use @ref array(std::initializer_list<basic_json>)
-      with an empty initializer list in this case
-    - arrays whose elements satisfy rule 2: use @ref
-      array(std::initializer_list<basic_json>) with the same initializer list
-      in this case
-
-    @note When used without parentheses around an empty initializer list, @ref
-    basic_json() is called instead of this function, yielding the JSON null
-    value.
-
-    @param[in] init  initializer list with JSON values
-
-    @param[in] type_deduction internal parameter; when set to `true`, the type
-    of the JSON value is deducted from the initializer list @a init; when set
-    to `false`, the type provided via @a manual_type is forced. This mode is
-    used by the functions @ref array(std::initializer_list<basic_json>) and
-    @ref object(std::initializer_list<basic_json>).
-
-    @param[in] manual_type internal parameter; when @a type_deduction is set
-    to `false`, the created JSON value will use the provided type (only @ref
-    value_t::array and @ref value_t::object are valid); when @a type_deduction
-    is set to `true`, this parameter has no effect
-
-    @throw std::domain_error if @a type_deduction is `false`, @a manual_type
-    is `value_t::object`, but @a init contains an element which is not a pair
-    whose first element is a string; example: `"cannot create object from
-    initializer list"`
-
-    @complexity Linear in the size of the initializer list @a init.
-
-    @liveexample{The example below shows how JSON values are created from
-    initializer lists.,basic_json__list_init_t}
-
-    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
-    value from an initializer list
-    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
-    value from an initializer list
-
-    @since version 1.0.0
-    */
-    basic_json(std::initializer_list<basic_json> init,
-               bool type_deduction = true,
-               value_t manual_type = value_t::array)
-    {
-        // check if each element is an array with two elements whose first
-        // element is a string
-        bool is_an_object = std::all_of(init.begin(), init.end(),
-                                        [](const basic_json & element)
-        {
-            return element.is_array() and element.size() == 2 and element[0].is_string();
-        });
-
-        // adjust type if type deduction is not wanted
-        if (not type_deduction)
-        {
-            // if array is wanted, do not create an object though possible
-            if (manual_type == value_t::array)
-            {
-                is_an_object = false;
-            }
-
-            // if object is wanted but impossible, throw an exception
-            if (manual_type == value_t::object and not is_an_object)
-            {
-                throw std::domain_error("cannot create object from initializer list");
-            }
-        }
-
-        if (is_an_object)
-        {
-            // the initializer list is a list of pairs -> create object
-            m_type = value_t::object;
-            m_value = value_t::object;
-
-            std::for_each(init.begin(), init.end(), [this](const basic_json & element)
-            {
-                m_value.object->emplace(*(element[0].m_value.string), element[1]);
-            });
-        }
-        else
-        {
-            // the initializer list describes an array -> create array
-            m_type = value_t::array;
-            m_value.array = create<array_t>(init);
-        }
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief explicitly create an array from an initializer list
-
-    Creates a JSON array value from a given initializer list. That is, given a
-    list of values `a, b, c`, creates the JSON value `[a, b, c]`. If the
-    initializer list is empty, the empty array `[]` is created.
-
-    @note This function is only needed to express two edge cases that cannot
-    be realized with the initializer list constructor (@ref
-    basic_json(std::initializer_list<basic_json>, bool, value_t)). These cases
-    are:
-    1. creating an array whose elements are all pairs whose first element is a
-    string -- in this case, the initializer list constructor would create an
-    object, taking the first elements as keys
-    2. creating an empty array -- passing the empty initializer list to the
-    initializer list constructor yields an empty object
-
-    @param[in] init  initializer list with JSON values to create an array from
-    (optional)
-
-    @return JSON array value
-
-    @complexity Linear in the size of @a init.
-
-    @liveexample{The following code shows an example for the `array`
-    function.,array}
-
-    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
-    create a JSON value from an initializer list
-    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
-    value from an initializer list
-
-    @since version 1.0.0
-    */
-    static basic_json array(std::initializer_list<basic_json> init =
-                                std::initializer_list<basic_json>())
-    {
-        return basic_json(init, false, value_t::array);
-    }
-
-    /*!
-    @brief explicitly create an object from an initializer list
-
-    Creates a JSON object value from a given initializer list. The initializer
-    lists elements must be pairs, and their first elements must be strings. If
-    the initializer list is empty, the empty object `{}` is created.
-
-    @note This function is only added for symmetry reasons. In contrast to the
-    related function @ref array(std::initializer_list<basic_json>), there are
-    no cases which can only be expressed by this function. That is, any
-    initializer list @a init can also be passed to the initializer list
-    constructor @ref basic_json(std::initializer_list<basic_json>, bool,
-    value_t).
-
-    @param[in] init  initializer list to create an object from (optional)
-
-    @return JSON object value
-
-    @throw std::domain_error if @a init is not a pair whose first elements are
-    strings; thrown by
-    @ref basic_json(std::initializer_list<basic_json>, bool, value_t)
-
-    @complexity Linear in the size of @a init.
-
-    @liveexample{The following code shows an example for the `object`
-    function.,object}
-
-    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
-    create a JSON value from an initializer list
-    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
-    value from an initializer list
-
-    @since version 1.0.0
-    */
-    static basic_json object(std::initializer_list<basic_json> init =
-                                 std::initializer_list<basic_json>())
-    {
-        return basic_json(init, false, value_t::object);
-    }
-
-    /*!
-    @brief construct an array with count copies of given value
-
-    Constructs a JSON array value by creating @a cnt copies of a passed value.
-    In case @a cnt is `0`, an empty array is created. As postcondition,
-    `std::distance(begin(),end()) == cnt` holds.
-
-    @param[in] cnt  the number of JSON copies of @a val to create
-    @param[in] val  the JSON value to copy
-
-    @complexity Linear in @a cnt.
-
-    @liveexample{The following code shows examples for the @ref
-    basic_json(size_type\, const basic_json&)
-    constructor.,basic_json__size_type_basic_json}
-
-    @since version 1.0.0
-    */
-    basic_json(size_type cnt, const basic_json& val)
-        : m_type(value_t::array)
-    {
-        m_value.array = create<array_t>(cnt, val);
-        assert_invariant();
-    }
-
-    /*!
-    @brief construct a JSON container given an iterator range
-
-    Constructs the JSON value with the contents of the range `[first, last)`.
-    The semantics depends on the different types a JSON value can have:
-    - In case of primitive types (number, boolean, or string), @a first must
-      be `begin()` and @a last must be `end()`. In this case, the value is
-      copied. Otherwise, std::out_of_range is thrown.
-    - In case of structured types (array, object), the constructor behaves as
-      similar versions for `std::vector`.
-    - In case of a null type, std::domain_error is thrown.
-
-    @tparam InputIT an input iterator type (@ref iterator or @ref
-    const_iterator)
-
-    @param[in] first begin of the range to copy from (included)
-    @param[in] last end of the range to copy from (excluded)
-
-    @pre Iterators @a first and @a last must be initialized.
-
-    @throw std::domain_error if iterators are not compatible; that is, do not
-    belong to the same JSON value; example: `"iterators are not compatible"`
-    @throw std::out_of_range if iterators are for a primitive type (number,
-    boolean, or string) where an out of range error can be detected easily;
-    example: `"iterators out of range"`
-    @throw std::bad_alloc if allocation for object, array, or string fails
-    @throw std::domain_error if called with a null value; example: `"cannot
-    use construct with iterators from null"`
-
-    @complexity Linear in distance between @a first and @a last.
-
-    @liveexample{The example below shows several ways to create JSON values by
-    specifying a subrange with iterators.,basic_json__InputIt_InputIt}
-
-    @since version 1.0.0
-    */
-    template <class InputIT, typename
-              std::enable_if<
-                  std::is_same<InputIT, typename basic_json_t::iterator>::value or
-                  std::is_same<InputIT, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
-    basic_json(InputIT first, InputIT last)
-    {
-        assert(first.m_object != nullptr);
-        assert(last.m_object != nullptr);
-
-        // make sure iterator fits the current value
-        if (first.m_object != last.m_object)
-        {
-            throw std::domain_error("iterators are not compatible");
-        }
-
-        // copy type from first iterator
-        m_type = first.m_object->m_type;
-
-        // check if iterator range is complete for primitive values
-        switch (m_type)
-        {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
-            {
-                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
-                {
-                    throw std::out_of_range("iterators out of range");
-                }
-                break;
-            }
-
-            default:
-            {
-                break;
-            }
-        }
-
-        switch (m_type)
-        {
-            case value_t::number_integer:
-            {
-                m_value.number_integer = first.m_object->m_value.number_integer;
-                break;
-            }
-
-            case value_t::number_unsigned:
-            {
-                m_value.number_unsigned = first.m_object->m_value.number_unsigned;
-                break;
-            }
-
-            case value_t::number_float:
-            {
-                m_value.number_float = first.m_object->m_value.number_float;
-                break;
-            }
-
-            case value_t::boolean:
-            {
-                m_value.boolean = first.m_object->m_value.boolean;
-                break;
-            }
-
-            case value_t::string:
-            {
-                m_value = *first.m_object->m_value.string;
-                break;
-            }
-
-            case value_t::object:
-            {
-                m_value.object = create<object_t>(first.m_it.object_iterator, last.m_it.object_iterator);
-                break;
-            }
-
-            case value_t::array:
-            {
-                m_value.array = create<array_t>(first.m_it.array_iterator, last.m_it.array_iterator);
-                break;
-            }
-
-            default:
-            {
-                throw std::domain_error("cannot use construct with iterators from " + first.m_object->type_name());
-            }
-        }
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief construct a JSON value given an input stream
-
-    @param[in,out] i  stream to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below demonstrates constructing a JSON value from
-    a `std::stringstream` with and without callback
-    function.,basic_json__istream}
-
-    @since version 2.0.0
-    */
-    explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)
-    {
-        *this = parser(i, cb).parse();
-        assert_invariant();
-    }
-
-    ///////////////////////////////////////
-    // other constructors and destructor //
-    ///////////////////////////////////////
-
-    /*!
-    @brief copy constructor
-
-    Creates a copy of a given JSON value.
-
-    @param[in] other  the JSON value to copy
-
-    @complexity Linear in the size of @a other.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-    - As postcondition, it holds: `other == basic_json(other)`.
-
-    @throw std::bad_alloc if allocation for object, array, or string fails.
-
-    @liveexample{The following code shows an example for the copy
-    constructor.,basic_json__basic_json}
-
-    @since version 1.0.0
-    */
-    basic_json(const basic_json& other)
-        : m_type(other.m_type)
-    {
-        // check of passed value is valid
-        other.assert_invariant();
-
-        switch (m_type)
-        {
-            case value_t::object:
-            {
-                m_value = *other.m_value.object;
-                break;
-            }
-
-            case value_t::array:
-            {
-                m_value = *other.m_value.array;
-                break;
-            }
-
-            case value_t::string:
-            {
-                m_value = *other.m_value.string;
-                break;
-            }
-
-            case value_t::boolean:
-            {
-                m_value = other.m_value.boolean;
-                break;
-            }
-
-            case value_t::number_integer:
-            {
-                m_value = other.m_value.number_integer;
-                break;
-            }
-
-            case value_t::number_unsigned:
-            {
-                m_value = other.m_value.number_unsigned;
-                break;
-            }
-
-            case value_t::number_float:
-            {
-                m_value = other.m_value.number_float;
-                break;
-            }
-
-            default:
-            {
-                break;
-            }
-        }
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief move constructor
-
-    Move constructor. Constructs a JSON value with the contents of the given
-    value @a other using move semantics. It "steals" the resources from @a
-    other and leaves it as JSON null value.
-
-    @param[in,out] other  value to move to this object
-
-    @post @a other is a JSON null value
-
-    @complexity Constant.
-
-    @liveexample{The code below shows the move constructor explicitly called
-    via std::move.,basic_json__moveconstructor}
-
-    @since version 1.0.0
-    */
-    basic_json(basic_json&& other) noexcept
-        : m_type(std::move(other.m_type)),
-          m_value(std::move(other.m_value))
-    {
-        // check that passed value is valid
-        other.assert_invariant();
-
-        // invalidate payload
-        other.m_type = value_t::null;
-        other.m_value = {};
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief copy assignment
-
-    Copy assignment operator. Copies a JSON value via the "copy and swap"
-    strategy: It is expressed in terms of the copy constructor, destructor,
-    and the swap() member function.
-
-    @param[in] other  value to copy from
-
-    @complexity Linear.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-
-    @liveexample{The code below shows and example for the copy assignment. It
-    creates a copy of value `a` which is then swapped with `b`. Finally\, the
-    copy of `a` (which is the null value after the swap) is
-    destroyed.,basic_json__copyassignment}
-
-    @since version 1.0.0
-    */
-    reference& operator=(basic_json other) noexcept (
-        std::is_nothrow_move_constructible<value_t>::value and
-        std::is_nothrow_move_assignable<value_t>::value and
-        std::is_nothrow_move_constructible<json_value>::value and
-        std::is_nothrow_move_assignable<json_value>::value
-    )
-    {
-        // check that passed value is valid
-        other.assert_invariant();
-
-        using std::swap;
-        swap(m_type, other.m_type);
-        swap(m_value, other.m_value);
-
-        assert_invariant();
-        return *this;
-    }
-
-    /*!
-    @brief destructor
-
-    Destroys the JSON value and frees all allocated memory.
-
-    @complexity Linear.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-    - All stored elements are destroyed and all memory is freed.
-
-    @since version 1.0.0
-    */
-    ~basic_json()
-    {
-        assert_invariant();
-
-        switch (m_type)
-        {
-            case value_t::object:
-            {
-                AllocatorType<object_t> alloc;
-                alloc.destroy(m_value.object);
-                alloc.deallocate(m_value.object, 1);
-                break;
-            }
-
-            case value_t::array:
-            {
-                AllocatorType<array_t> alloc;
-                alloc.destroy(m_value.array);
-                alloc.deallocate(m_value.array, 1);
-                break;
-            }
-
-            case value_t::string:
-            {
-                AllocatorType<string_t> alloc;
-                alloc.destroy(m_value.string);
-                alloc.deallocate(m_value.string, 1);
-                break;
-            }
-
-            default:
-            {
-                // all other types need no specific destructor
-                break;
-            }
-        }
-    }
-
-    /// @}
-
-  public:
-    ///////////////////////
-    // object inspection //
-    ///////////////////////
-
-    /// @name object inspection
-    /// Functions to inspect the type of a JSON value.
-    /// @{
-
-    /*!
-    @brief serialization
-
-    Serialization function for JSON values. The function tries to mimic
-    Python's `json.dumps()` function, and currently supports its @a indent
-    parameter.
-
-    @param[in] indent If indent is nonnegative, then array elements and object
-    members will be pretty-printed with that indent level. An indent level of
-    `0` will only insert newlines. `-1` (the default) selects the most compact
-    representation.
-
-    @return string containing the serialization of the JSON value
-
-    @complexity Linear.
-
-    @liveexample{The following example shows the effect of different @a indent
-    parameters to the result of the serialization.,dump}
-
-    @see https://docs.python.org/2/library/json.html#json.dump
-
-    @since version 1.0.0
-    */
-    string_t dump(const int indent = -1) const
-    {
-        std::stringstream ss;
-        // fix locale problems
-        ss.imbue(std::locale(std::locale(), new DecimalSeparator));
-
-        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
-        // string->float->string, string->double->string or string->long
-        // double->string; to be safe, we read this value from
-        // std::numeric_limits<number_float_t>::digits10
-        ss.precision(std::numeric_limits<double>::digits10);
-
-        if (indent >= 0)
-        {
-            dump(ss, true, static_cast<unsigned int>(indent));
-        }
-        else
-        {
-            dump(ss, false, 0);
-        }
-
-        return ss.str();
-    }
-
-    /*!
-    @brief return the type of the JSON value (explicit)
-
-    Return the type of the JSON value as a value from the @ref value_t
-    enumeration.
-
-    @return the type of the JSON value
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `type()` for all JSON
-    types.,type}
-
-    @since version 1.0.0
-    */
-    constexpr value_t type() const noexcept
-    {
-        return m_type;
-    }
-
-    /*!
-    @brief return whether type is primitive
-
-    This function returns true iff the JSON type is primitive (string, number,
-    boolean, or null).
-
-    @return `true` if type is primitive (string, number, boolean, or null),
-    `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_primitive()` for all JSON
-    types.,is_primitive}
-
-    @sa @ref is_structured() -- returns whether JSON value is structured
-    @sa @ref is_null() -- returns whether JSON value is `null`
-    @sa @ref is_string() -- returns whether JSON value is a string
-    @sa @ref is_boolean() -- returns whether JSON value is a boolean
-    @sa @ref is_number() -- returns whether JSON value is a number
-
-    @since version 1.0.0
-    */
-    constexpr bool is_primitive() const noexcept
-    {
-        return is_null() or is_string() or is_boolean() or is_number();
-    }
-
-    /*!
-    @brief return whether type is structured
-
-    This function returns true iff the JSON type is structured (array or
-    object).
-
-    @return `true` if type is structured (array or object), `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_structured()` for all JSON
-    types.,is_structured}
-
-    @sa @ref is_primitive() -- returns whether value is primitive
-    @sa @ref is_array() -- returns whether value is an array
-    @sa @ref is_object() -- returns whether value is an object
-
-    @since version 1.0.0
-    */
-    constexpr bool is_structured() const noexcept
-    {
-        return is_array() or is_object();
-    }
-
-    /*!
-    @brief return whether value is null
-
-    This function returns true iff the JSON value is null.
-
-    @return `true` if type is null, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_null()` for all JSON
-    types.,is_null}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_null() const noexcept
-    {
-        return m_type == value_t::null;
-    }
-
-    /*!
-    @brief return whether value is a boolean
-
-    This function returns true iff the JSON value is a boolean.
-
-    @return `true` if type is boolean, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_boolean()` for all JSON
-    types.,is_boolean}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_boolean() const noexcept
-    {
-        return m_type == value_t::boolean;
-    }
-
-    /*!
-    @brief return whether value is a number
-
-    This function returns true iff the JSON value is a number. This includes
-    both integer and floating-point values.
-
-    @return `true` if type is number (regardless whether integer, unsigned
-    integer or floating-type), `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number()` for all JSON
-    types.,is_number}
-
-    @sa @ref is_number_integer() -- check if value is an integer or unsigned
-    integer number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
-    @sa @ref is_number_float() -- check if value is a floating-point number
-
-    @since version 1.0.0
-    */
-    constexpr bool is_number() const noexcept
-    {
-        return is_number_integer() or is_number_float();
-    }
-
-    /*!
-    @brief return whether value is an integer number
-
-    This function returns true iff the JSON value is an integer or unsigned
-    integer number. This excludes floating-point values.
-
-    @return `true` if type is an integer or unsigned integer number, `false`
-    otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number_integer()` for all
-    JSON types.,is_number_integer}
-
-    @sa @ref is_number() -- check if value is a number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
-    @sa @ref is_number_float() -- check if value is a floating-point number
-
-    @since version 1.0.0
-    */
-    constexpr bool is_number_integer() const noexcept
-    {
-        return m_type == value_t::number_integer or m_type == value_t::number_unsigned;
-    }
-
-    /*!
-    @brief return whether value is an unsigned integer number
-
-    This function returns true iff the JSON value is an unsigned integer
-    number. This excludes floating-point and (signed) integer values.
-
-    @return `true` if type is an unsigned integer number, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number_unsigned()` for all
-    JSON types.,is_number_unsigned}
-
-    @sa @ref is_number() -- check if value is a number
-    @sa @ref is_number_integer() -- check if value is an integer or unsigned
-    integer number
-    @sa @ref is_number_float() -- check if value is a floating-point number
-
-    @since version 2.0.0
-    */
-    constexpr bool is_number_unsigned() const noexcept
-    {
-        return m_type == value_t::number_unsigned;
-    }
-
-    /*!
-    @brief return whether value is a floating-point number
-
-    This function returns true iff the JSON value is a floating-point number.
-    This excludes integer and unsigned integer values.
-
-    @return `true` if type is a floating-point number, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number_float()` for all
-    JSON types.,is_number_float}
-
-    @sa @ref is_number() -- check if value is number
-    @sa @ref is_number_integer() -- check if value is an integer number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
-
-    @since version 1.0.0
-    */
-    constexpr bool is_number_float() const noexcept
-    {
-        return m_type == value_t::number_float;
-    }
-
-    /*!
-    @brief return whether value is an object
-
-    This function returns true iff the JSON value is an object.
-
-    @return `true` if type is object, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_object()` for all JSON
-    types.,is_object}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_object() const noexcept
-    {
-        return m_type == value_t::object;
-    }
-
-    /*!
-    @brief return whether value is an array
-
-    This function returns true iff the JSON value is an array.
-
-    @return `true` if type is array, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_array()` for all JSON
-    types.,is_array}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_array() const noexcept
-    {
-        return m_type == value_t::array;
-    }
-
-    /*!
-    @brief return whether value is a string
-
-    This function returns true iff the JSON value is a string.
-
-    @return `true` if type is string, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_string()` for all JSON
-    types.,is_string}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_string() const noexcept
-    {
-        return m_type == value_t::string;
-    }
-
-    /*!
-    @brief return whether value is discarded
-
-    This function returns true iff the JSON value was discarded during parsing
-    with a callback function (see @ref parser_callback_t).
-
-    @note This function will always be `false` for JSON values after parsing.
-    That is, discarded values can only occur during parsing, but will be
-    removed when inside a structured value or replaced by null in other cases.
-
-    @return `true` if type is discarded, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_discarded()` for all JSON
-    types.,is_discarded}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_discarded() const noexcept
-    {
-        return m_type == value_t::discarded;
-    }
-
-    /*!
-    @brief return the type of the JSON value (implicit)
-
-    Implicitly return the type of the JSON value as a value from the @ref
-    value_t enumeration.
-
-    @return the type of the JSON value
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies the @ref value_t operator for
-    all JSON types.,operator__value_t}
-
-    @since version 1.0.0
-    */
-    constexpr operator value_t() const noexcept
-    {
-        return m_type;
-    }
-
-    /// @}
-
-  private:
-    //////////////////
-    // value access //
-    //////////////////
-
-    /// get an object (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<typename object_t::key_type, typename T::key_type>::value and
-                  std::is_convertible<basic_json_t, typename T::mapped_type>::value
-                  , int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_object())
-        {
-            return T(m_value.object->begin(), m_value.object->end());
-        }
-        else
-        {
-            throw std::domain_error("type must be object, but is " + type_name());
-        }
-    }
-
-    /// get an object (explicit)
-    object_t get_impl(object_t*) const
-    {
-        if (is_object())
-        {
-            return *(m_value.object);
-        }
-        else
-        {
-            throw std::domain_error("type must be object, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, typename T::value_type>::value and
-                  not std::is_same<basic_json_t, typename T::value_type>::value and
-                  not std::is_arithmetic<T>::value and
-                  not std::is_convertible<std::string, T>::value and
-                  not has_mapped_type<T>::value
-                  , int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_array())
-        {
-            T to_vector;
-            std::transform(m_value.array->begin(), m_value.array->end(),
-                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
-            {
-                return i.get<typename T::value_type>();
-            });
-            return to_vector;
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, T>::value and
-                  not std::is_same<basic_json_t, T>::value
-                  , int>::type = 0>
-    std::vector<T> get_impl(std::vector<T>*) const
-    {
-        if (is_array())
-        {
-            std::vector<T> to_vector;
-            to_vector.reserve(m_value.array->size());
-            std::transform(m_value.array->begin(), m_value.array->end(),
-                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
-            {
-                return i.get<T>();
-            });
-            return to_vector;
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_same<basic_json, typename T::value_type>::value and
-                  not has_mapped_type<T>::value
-                  , int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_array())
-        {
-            return T(m_value.array->begin(), m_value.array->end());
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    array_t get_impl(array_t*) const
-    {
-        if (is_array())
-        {
-            return *(m_value.array);
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get a string (explicit)
-    template <typename T, typename
-              std::enable_if<
-                  std::is_convertible<string_t, T>::value
-                  , int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_string())
-        {
-            return *m_value.string;
-        }
-        else
-        {
-            throw std::domain_error("type must be string, but is " + type_name());
-        }
-    }
-
-    /// get a number (explicit)
-    template<typename T, typename
-             std::enable_if<
-                 std::is_arithmetic<T>::value
-                 , int>::type = 0>
-    T get_impl(T*) const
-    {
-        switch (m_type)
-        {
-            case value_t::number_integer:
-            {
-                return static_cast<T>(m_value.number_integer);
-            }
-
-            case value_t::number_unsigned:
-            {
-                return static_cast<T>(m_value.number_unsigned);
-            }
-
-            case value_t::number_float:
-            {
-                return static_cast<T>(m_value.number_float);
-            }
-
-            default:
-            {
-                throw std::domain_error("type must be number, but is " + type_name());
-            }
-        }
-    }
-
-    /// get a boolean (explicit)
-    constexpr boolean_t get_impl(boolean_t*) const
-    {
-        return is_boolean()
-               ? m_value.boolean
-               : throw std::domain_error("type must be boolean, but is " + type_name());
-    }
-
-    /// get a pointer to the value (object)
-    object_t* get_impl_ptr(object_t*) noexcept
-    {
-        return is_object() ? m_value.object : nullptr;
-    }
-
-    /// get a pointer to the value (object)
-    constexpr const object_t* get_impl_ptr(const object_t*) const noexcept
-    {
-        return is_object() ? m_value.object : nullptr;
-    }
-
-    /// get a pointer to the value (array)
-    array_t* get_impl_ptr(array_t*) noexcept
-    {
-        return is_array() ? m_value.array : nullptr;
-    }
-
-    /// get a pointer to the value (array)
-    constexpr const array_t* get_impl_ptr(const array_t*) const noexcept
-    {
-        return is_array() ? m_value.array : nullptr;
-    }
-
-    /// get a pointer to the value (string)
-    string_t* get_impl_ptr(string_t*) noexcept
-    {
-        return is_string() ? m_value.string : nullptr;
-    }
-
-    /// get a pointer to the value (string)
-    constexpr const string_t* get_impl_ptr(const string_t*) const noexcept
-    {
-        return is_string() ? m_value.string : nullptr;
-    }
-
-    /// get a pointer to the value (boolean)
-    boolean_t* get_impl_ptr(boolean_t*) noexcept
-    {
-        return is_boolean() ? &m_value.boolean : nullptr;
-    }
-
-    /// get a pointer to the value (boolean)
-    constexpr const boolean_t* get_impl_ptr(const boolean_t*) const noexcept
-    {
-        return is_boolean() ? &m_value.boolean : nullptr;
-    }
-
-    /// get a pointer to the value (integer number)
-    number_integer_t* get_impl_ptr(number_integer_t*) noexcept
-    {
-        return is_number_integer() ? &m_value.number_integer : nullptr;
-    }
-
-    /// get a pointer to the value (integer number)
-    constexpr const number_integer_t* get_impl_ptr(const number_integer_t*) const noexcept
-    {
-        return is_number_integer() ? &m_value.number_integer : nullptr;
-    }
-
-    /// get a pointer to the value (unsigned number)
-    number_unsigned_t* get_impl_ptr(number_unsigned_t*) noexcept
-    {
-        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
-    }
-
-    /// get a pointer to the value (unsigned number)
-    constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t*) const noexcept
-    {
-        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
-    }
-
-    /// get a pointer to the value (floating-point number)
-    number_float_t* get_impl_ptr(number_float_t*) noexcept
-    {
-        return is_number_float() ? &m_value.number_float : nullptr;
-    }
-
-    /// get a pointer to the value (floating-point number)
-    constexpr const number_float_t* get_impl_ptr(const number_float_t*) const noexcept
-    {
-        return is_number_float() ? &m_value.number_float : nullptr;
-    }
-
-    /*!
-    @brief helper function to implement get_ref()
-
-    This funcion helps to implement get_ref() without code duplication for
-    const and non-const overloads
-
-    @tparam ThisType will be deduced as `basic_json` or `const basic_json`
-
-    @throw std::domain_error if ReferenceType does not match underlying value
-    type of the current JSON
-    */
-    template<typename ReferenceType, typename ThisType>
-    static ReferenceType get_ref_impl(ThisType& obj)
-    {
-        // helper type
-        using PointerType = typename std::add_pointer<ReferenceType>::type;
-
-        // delegate the call to get_ptr<>()
-        auto ptr = obj.template get_ptr<PointerType>();
-
-        if (ptr != nullptr)
-        {
-            return *ptr;
-        }
-        else
-        {
-            throw std::domain_error("incompatible ReferenceType for get_ref, actual type is " +
-                                    obj.type_name());
-        }
-    }
-
-  public:
-
-    /// @name value access
-    /// Direct access to the stored value of a JSON value.
-    /// @{
-
-    /*!
-    @brief get a value (explicit)
-
-    Explicit type conversion between the JSON value and a compatible value.
-
-    @tparam ValueType non-pointer type compatible to the JSON value, for
-    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
-    `std::vector` types for JSON arrays
-
-    @return copy of the JSON value, converted to type @a ValueType
-
-    @throw std::domain_error in case passed type @a ValueType is incompatible
-    to JSON; example: `"type must be object, but is null"`
-
-    @complexity Linear in the size of the JSON value.
-
-    @liveexample{The example below shows several conversions from JSON values
-    to other types. There a few things to note: (1) Floating-point numbers can
-    be converted to integers\, (2) A JSON array can be converted to a standard
-    `std::vector<short>`\, (3) A JSON object can be converted to C++
-    associative containers such as `std::unordered_map<std::string\,
-    json>`.,get__ValueType_const}
-
-    @internal
-    The idea of using a casted null pointer to choose the correct
-    implementation is from <http://stackoverflow.com/a/8315197/266378>.
-    @endinternal
-
-    @sa @ref operator ValueType() const for implicit conversion
-    @sa @ref get() for pointer-member access
-
-    @since version 1.0.0
-    */
-    template<typename ValueType, typename
-             std::enable_if<
-                 not std::is_pointer<ValueType>::value
-                 , int>::type = 0>
-    ValueType get() const
-    {
-        return get_impl(static_cast<ValueType*>(nullptr));
-    }
-
-    /*!
-    @brief get a pointer value (explicit)
-
-    Explicit pointer access to the internally stored JSON value. No copies are
-    made.
-
-    @warning The pointer becomes invalid if the underlying JSON object
-    changes.
-
-    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
-    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
-    @ref number_unsigned_t, or @ref number_float_t.
-
-    @return pointer to the internally stored JSON value if the requested
-    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how pointers to internal values of a
-    JSON value can be requested. Note that no type conversions are made and a
-    `nullptr` is returned if the value and the requested pointer type does not
-    match.,get__PointerType}
-
-    @sa @ref get_ptr() for explicit pointer-member access
-
-    @since version 1.0.0
-    */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
-    PointerType get() noexcept
-    {
-        // delegate the call to get_ptr
-        return get_ptr<PointerType>();
-    }
-
-    /*!
-    @brief get a pointer value (explicit)
-    @copydoc get()
-    */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
-    constexpr const PointerType get() const noexcept
-    {
-        // delegate the call to get_ptr
-        return get_ptr<PointerType>();
-    }
-
-    /*!
-    @brief get a pointer value (implicit)
-
-    Implicit pointer access to the internally stored JSON value. No copies are
-    made.
-
-    @warning Writing data to the pointee of the result yields an undefined
-    state.
-
-    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
-    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
-    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
-    assertion.
-
-    @return pointer to the internally stored JSON value if the requested
-    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how pointers to internal values of a
-    JSON value can be requested. Note that no type conversions are made and a
-    `nullptr` is returned if the value and the requested pointer type does not
-    match.,get_ptr}
-
-    @since version 1.0.0
-    */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
-    PointerType get_ptr() noexcept
-    {
-        // get the type of the PointerType (remove pointer and const)
-        using pointee_t = typename std::remove_const<typename
-                          std::remove_pointer<typename
-                          std::remove_const<PointerType>::type>::type>::type;
-        // make sure the type matches the allowed types
-        static_assert(
-            std::is_same<object_t, pointee_t>::value
-            or std::is_same<array_t, pointee_t>::value
-            or std::is_same<string_t, pointee_t>::value
-            or std::is_same<boolean_t, pointee_t>::value
-            or std::is_same<number_integer_t, pointee_t>::value
-            or std::is_same<number_unsigned_t, pointee_t>::value
-            or std::is_same<number_float_t, pointee_t>::value
-            , "incompatible pointer type");
-
-        // delegate the call to get_impl_ptr<>()
-        return get_impl_ptr(static_cast<PointerType>(nullptr));
-    }
-
-    /*!
-    @brief get a pointer value (implicit)
-    @copydoc get_ptr()
-    */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 and std::is_const<typename std::remove_pointer<PointerType>::type>::value
-                 , int>::type = 0>
-    constexpr const PointerType get_ptr() const noexcept
-    {
-        // get the type of the PointerType (remove pointer and const)
-        using pointee_t = typename std::remove_const<typename
-                          std::remove_pointer<typename
-                          std::remove_const<PointerType>::type>::type>::type;
-        // make sure the type matches the allowed types
-        static_assert(
-            std::is_same<object_t, pointee_t>::value
-            or std::is_same<array_t, pointee_t>::value
-            or std::is_same<string_t, pointee_t>::value
-            or std::is_same<boolean_t, pointee_t>::value
-            or std::is_same<number_integer_t, pointee_t>::value
-            or std::is_same<number_unsigned_t, pointee_t>::value
-            or std::is_same<number_float_t, pointee_t>::value
-            , "incompatible pointer type");
-
-        // delegate the call to get_impl_ptr<>() const
-        return get_impl_ptr(static_cast<const PointerType>(nullptr));
-    }
-
-    /*!
-    @brief get a reference value (implicit)
-
-    Implict reference access to the internally stored JSON value. No copies
-    are made.
-
-    @warning Writing data to the referee of the result yields an undefined
-    state.
-
-    @tparam ReferenceType reference type; must be a reference to @ref array_t,
-    @ref object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, or
-    @ref number_float_t. Enforced by static assertion.
-
-    @return reference to the internally stored JSON value if the requested
-    reference type @a ReferenceType fits to the JSON value; throws
-    std::domain_error otherwise
-
-    @throw std::domain_error in case passed type @a ReferenceType is
-    incompatible with the stored JSON value
-
-    @complexity Constant.
-
-    @liveexample{The example shows several calls to `get_ref()`.,get_ref}
-
-    @since version 1.1.0
-    */
-    template<typename ReferenceType, typename
-             std::enable_if<
-                 std::is_reference<ReferenceType>::value
-                 , int>::type = 0>
-    ReferenceType get_ref()
-    {
-        // delegate call to get_ref_impl
-        return get_ref_impl<ReferenceType>(*this);
-    }
-
-    /*!
-    @brief get a reference value (implicit)
-    @copydoc get_ref()
-    */
-    template<typename ReferenceType, typename
-             std::enable_if<
-                 std::is_reference<ReferenceType>::value
-                 and std::is_const<typename std::remove_reference<ReferenceType>::type>::value
-                 , int>::type = 0>
-    ReferenceType get_ref() const
-    {
-        // delegate call to get_ref_impl
-        return get_ref_impl<ReferenceType>(*this);
-    }
-
-    /*!
-    @brief get a value (implicit)
-
-    Implicit type conversion between the JSON value and a compatible value.
-    The call is realized by calling @ref get() const.
-
-    @tparam ValueType non-pointer type compatible to the JSON value, for
-    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
-    `std::vector` types for JSON arrays. The character type of @ref string_t
-    as well as an initializer list of this type is excluded to avoid
-    ambiguities as these types implicitly convert to `std::string`.
-
-    @return copy of the JSON value, converted to type @a ValueType
-
-    @throw std::domain_error in case passed type @a ValueType is incompatible
-    to JSON, thrown by @ref get() const
-
-    @complexity Linear in the size of the JSON value.
-
-    @liveexample{The example below shows several conversions from JSON values
-    to other types. There a few things to note: (1) Floating-point numbers can
-    be converted to integers\, (2) A JSON array can be converted to a standard
-    `std::vector<short>`\, (3) A JSON object can be converted to C++
-    associative containers such as `std::unordered_map<std::string\,
-    json>`.,operator__ValueType}
-
-    @since version 1.0.0
-    */
-    template < typename ValueType, typename
-               std::enable_if <
-                   not std::is_pointer<ValueType>::value
-                   and not std::is_same<ValueType, typename string_t::value_type>::value
-#ifndef _MSC_VER  // Fix for issue #167 operator<< abiguity under VS2015
-                   and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
-#endif
-                   , int >::type = 0 >
-    operator ValueType() const
-    {
-        // delegate the call to get<>() const
-        return get<ValueType>();
-    }
-
-    /// @}
-
-
-    ////////////////////
-    // element access //
-    ////////////////////
-
-    /// @name element access
-    /// Access to the JSON value.
-    /// @{
-
-    /*!
-    @brief access specified array element with bounds checking
-
-    Returns a reference to the element at specified location @a idx, with
-    bounds checking.
-
-    @param[in] idx  index of the element to access
-
-    @return reference to the element at index @a idx
-
-    @throw std::domain_error if the JSON value is not an array; example:
-    `"cannot use at() with string"`
-    @throw std::out_of_range if the index @a idx is out of range of the array;
-    that is, `idx >= size()`; example: `"array index 7 is out of range"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how array elements can be read and
-    written using `at()`.,at__size_type}
-
-    @since version 1.0.0
-    */
-    reference at(size_type idx)
-    {
-        // at only works for arrays
-        if (is_array())
-        {
-            try
-            {
-                return m_value.array->at(idx);
-            }
-            catch (std::out_of_range&)
-            {
-                // create better exception explanation
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use at() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified array element with bounds checking
-
-    Returns a const reference to the element at specified location @a idx,
-    with bounds checking.
-
-    @param[in] idx  index of the element to access
-
-    @return const reference to the element at index @a idx
-
-    @throw std::domain_error if the JSON value is not an array; example:
-    `"cannot use at() with string"`
-    @throw std::out_of_range if the index @a idx is out of range of the array;
-    that is, `idx >= size()`; example: `"array index 7 is out of range"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how array elements can be read using
-    `at()`.,at__size_type_const}
-
-    @since version 1.0.0
-    */
-    const_reference at(size_type idx) const
-    {
-        // at only works for arrays
-        if (is_array())
-        {
-            try
-            {
-                return m_value.array->at(idx);
-            }
-            catch (std::out_of_range&)
-            {
-                // create better exception explanation
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use at() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element with bounds checking
-
-    Returns a reference to the element at with specified key @a key, with
-    bounds checking.
-
-    @param[in] key  key of the element to access
-
-    @return reference to the element at key @a key
-
-    @throw std::domain_error if the JSON value is not an object; example:
-    `"cannot use at() with boolean"`
-    @throw std::out_of_range if the key @a key is is not stored in the object;
-    that is, `find(key) == end()`; example: `"key "the fast" not found"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read and
-    written using `at()`.,at__object_t_key_type}
-
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    reference at(const typename object_t::key_type& key)
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            try
-            {
-                return m_value.object->at(key);
-            }
-            catch (std::out_of_range&)
-            {
-                // create better exception explanation
-                throw std::out_of_range("key '" + key + "' not found");
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use at() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element with bounds checking
-
-    Returns a const reference to the element at with specified key @a key,
-    with bounds checking.
-
-    @param[in] key  key of the element to access
-
-    @return const reference to the element at key @a key
-
-    @throw std::domain_error if the JSON value is not an object; example:
-    `"cannot use at() with boolean"`
-    @throw std::out_of_range if the key @a key is is not stored in the object;
-    that is, `find(key) == end()`; example: `"key "the fast" not found"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read using
-    `at()`.,at__object_t_key_type_const}
-
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    const_reference at(const typename object_t::key_type& key) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            try
-            {
-                return m_value.object->at(key);
-            }
-            catch (std::out_of_range&)
-            {
-                // create better exception explanation
-                throw std::out_of_range("key '" + key + "' not found");
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use at() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified array element
-
-    Returns a reference to the element at specified location @a idx.
-
-    @note If @a idx is beyond the range of the array (i.e., `idx >= size()`),
-    then the array is silently filled up with `null` values to make `idx` a
-    valid reference to the last stored element.
-
-    @param[in] idx  index of the element to access
-
-    @return reference to the element at index @a idx
-
-    @throw std::domain_error if JSON is not an array or null; example:
-    `"cannot use operator[] with string"`
-
-    @complexity Constant if @a idx is in the range of the array. Otherwise
-    linear in `idx - size()`.
-
-    @liveexample{The example below shows how array elements can be read and
-    written using `[]` operator. Note the addition of `null`
-    values.,operatorarray__size_type}
-
-    @since version 1.0.0
-    */
-    reference operator[](size_type idx)
-    {
-        // implicitly convert null value to an empty array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value.array = create<array_t>();
-            assert_invariant();
-        }
-
-        // operator[] only works for arrays
-        if (is_array())
-        {
-            // fill up array with null values if given idx is outside range
-            if (idx >= m_value.array->size())
-            {
-                m_value.array->insert(m_value.array->end(),
-                                      idx - m_value.array->size() + 1,
-                                      basic_json());
-            }
-
-            return m_value.array->operator[](idx);
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified array element
-
-    Returns a const reference to the element at specified location @a idx.
-
-    @param[in] idx  index of the element to access
-
-    @return const reference to the element at index @a idx
-
-    @throw std::domain_error if JSON is not an array; example: `"cannot use
-    operator[] with null"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how array elements can be read using
-    the `[]` operator.,operatorarray__size_type_const}
-
-    @since version 1.0.0
-    */
-    const_reference operator[](size_type idx) const
-    {
-        // const operator[] only works for arrays
-        if (is_array())
-        {
-            return m_value.array->operator[](idx);
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element
-
-    Returns a reference to the element at with specified key @a key.
-
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
-
-    @param[in] key  key of the element to access
-
-    @return reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    reference operator[](const typename object_t::key_type& key)
-    {
-        // implicitly convert null value to an empty object
-        if (is_null())
-        {
-            m_type = value_t::object;
-            m_value.object = create<object_t>();
-            assert_invariant();
-        }
-
-        // operator[] only works for objects
-        if (is_object())
-        {
-            return m_value.object->operator[](key);
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief read-only access specified object element
-
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
-
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
-
-    @param[in] key  key of the element to access
-
-    @return const reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    const_reference operator[](const typename object_t::key_type& key) const
-    {
-        // const operator[] only works for objects
-        if (is_object())
-        {
-            assert(m_value.object->find(key) != m_value.object->end());
-            return m_value.object->find(key)->second;
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element
-
-    Returns a reference to the element at with specified key @a key.
-
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
-
-    @param[in] key  key of the element to access
-
-    @return reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    template<typename T, std::size_t n>
-    reference operator[](T * (&key)[n])
-    {
-        return operator[](static_cast<const T>(key));
-    }
-
-    /*!
-    @brief read-only access specified object element
-
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
-
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
-
-    @note This function is required for compatibility reasons with Clang.
-
-    @param[in] key  key of the element to access
-
-    @return const reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    template<typename T, std::size_t n>
-    const_reference operator[](T * (&key)[n]) const
-    {
-        return operator[](static_cast<const T>(key));
-    }
-
-    /*!
-    @brief access specified object element
-
-    Returns a reference to the element at with specified key @a key.
-
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
-
-    @param[in] key  key of the element to access
-
-    @return reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.1.0
-    */
-    template<typename T>
-    reference operator[](T* key)
-    {
-        // implicitly convert null to object
-        if (is_null())
-        {
-            m_type = value_t::object;
-            m_value = value_t::object;
-            assert_invariant();
-        }
-
-        // at only works for objects
-        if (is_object())
-        {
-            return m_value.object->operator[](key);
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief read-only access specified object element
-
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
-
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
-
-    @param[in] key  key of the element to access
-
-    @return const reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.1.0
-    */
-    template<typename T>
-    const_reference operator[](T* key) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            assert(m_value.object->find(key) != m_value.object->end());
-            return m_value.object->find(key)->second;
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element with default value
-
-    Returns either a copy of an object's element at the specified key @a key
-    or a given default value if no element with key @a key exists.
-
-    The function is basically equivalent to executing
-    @code {.cpp}
-    try {
-        return at(key);
-    } catch(std::out_of_range) {
-        return default_value;
-    }
-    @endcode
-
-    @note Unlike @ref at(const typename object_t::key_type&), this function
-    does not throw if the given key @a key was not found.
-
-    @note Unlike @ref operator[](const typename object_t::key_type& key), this
-    function does not implicitly add an element to the position defined by @a
-    key. This function is furthermore also applicable to const objects.
-
-    @param[in] key  key of the element to access
-    @param[in] default_value  the value to return if @a key is not found
-
-    @tparam ValueType type compatible to JSON values, for instance `int` for
-    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
-    JSON arrays. Note the type of the expected value at @a key and the default
-    value @a default_value must be compatible.
-
-    @return copy of the element at key @a key or @a default_value if @a key
-    is not found
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    value() with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be queried
-    with a default value.,basic_json__value}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
-
-    @since version 1.0.0
-    */
-    template <class ValueType, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, ValueType>::value
-                  , int>::type = 0>
-    ValueType value(const typename object_t::key_type& key, ValueType default_value) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            // if key is found, return value and given default value otherwise
-            const auto it = find(key);
-            if (it != end())
-            {
-                return *it;
-            }
-            else
-            {
-                return default_value;
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use value() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief overload for a default value of type const char*
-    @copydoc basic_json::value(const typename object_t::key_type&, ValueType) const
-    */
-    string_t value(const typename object_t::key_type& key, const char* default_value) const
-    {
-        return value(key, string_t(default_value));
-    }
-
-    /*!
-    @brief access specified object element via JSON Pointer with default value
-
-    Returns either a copy of an object's element at the specified key @a key
-    or a given default value if no element with key @a key exists.
-
-    The function is basically equivalent to executing
-    @code {.cpp}
-    try {
-        return at(ptr);
-    } catch(std::out_of_range) {
-        return default_value;
-    }
-    @endcode
-
-    @note Unlike @ref at(const json_pointer&), this function does not throw
-    if the given key @a key was not found.
-
-    @param[in] ptr  a JSON pointer to the element to access
-    @param[in] default_value  the value to return if @a ptr found no value
-
-    @tparam ValueType type compatible to JSON values, for instance `int` for
-    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
-    JSON arrays. Note the type of the expected value at @a key and the default
-    value @a default_value must be compatible.
-
-    @return copy of the element at key @a key or @a default_value if @a key
-    is not found
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    value() with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be queried
-    with a default value.,basic_json__value_ptr}
-
-    @sa @ref operator[](const json_pointer&) for unchecked access by reference
-
-    @since version 2.0.2
-    */
-    template <class ValueType, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, ValueType>::value
-                  , int>::type = 0>
-    ValueType value(const json_pointer& ptr, ValueType default_value) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            // if pointer resolves a value, return it or use default value
-            try
-            {
-                return ptr.get_checked(this);
-            }
-            catch (std::out_of_range&)
-            {
-                return default_value;
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use value() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief overload for a default value of type const char*
-    @copydoc basic_json::value(const json_pointer&, ValueType) const
-    */
-    string_t value(const json_pointer& ptr, const char* default_value) const
-    {
-        return value(ptr, string_t(default_value));
-    }
-
-    /*!
-    @brief access the first element
-
-    Returns a reference to the first element in the container. For a JSON
-    container `c`, the expression `c.front()` is equivalent to `*c.begin()`.
-
-    @return In case of a structured type (array or object), a reference to the
-    first element is returned. In cast of number, string, or boolean values, a
-    reference to the value is returned.
-
-    @complexity Constant.
-
-    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
-    or an empty array or object (undefined behavior, guarded by assertions).
-    @post The JSON value remains unchanged.
-
-    @throw std::out_of_range when called on `null` value
-
-    @liveexample{The following code shows an example for `front()`.,front}
-
-    @sa @ref back() -- access the last element
-
-    @since version 1.0.0
-    */
-    reference front()
-    {
-        return *begin();
-    }
-
-    /*!
-    @copydoc basic_json::front()
-    */
-    const_reference front() const
-    {
-        return *cbegin();
-    }
-
-    /*!
-    @brief access the last element
-
-    Returns a reference to the last element in the container. For a JSON
-    container `c`, the expression `c.back()` is equivalent to
-    @code {.cpp}
-    auto tmp = c.end();
-    --tmp;
-    return *tmp;
-    @endcode
-
-    @return In case of a structured type (array or object), a reference to the
-    last element is returned. In cast of number, string, or boolean values, a
-    reference to the value is returned.
-
-    @complexity Constant.
-
-    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
-    or an empty array or object (undefined behavior, guarded by assertions).
-    @post The JSON value remains unchanged.
-
-    @throw std::out_of_range when called on `null` value.
-
-    @liveexample{The following code shows an example for `back()`.,back}
-
-    @sa @ref front() -- access the first element
-
-    @since version 1.0.0
-    */
-    reference back()
-    {
-        auto tmp = end();
-        --tmp;
-        return *tmp;
-    }
-
-    /*!
-    @copydoc basic_json::back()
-    */
-    const_reference back() const
-    {
-        auto tmp = cend();
-        --tmp;
-        return *tmp;
-    }
-
-    /*!
-    @brief remove element given an iterator
-
-    Removes the element specified by iterator @a pos. The iterator @a pos must
-    be valid and dereferenceable. Thus the `end()` iterator (which is valid,
-    but is not dereferenceable) cannot be used as a value for @a pos.
-
-    If called on a primitive type other than `null`, the resulting JSON value
-    will be `null`.
-
-    @param[in] pos iterator to the element to remove
-    @return Iterator following the last removed element. If the iterator @a
-    pos refers to the last element, the `end()` iterator is returned.
-
-    @tparam InteratorType an @ref iterator or @ref const_iterator
-
-    @post Invalidates iterators and references at or after the point of the
-    erase, including the `end()` iterator.
-
-    @throw std::domain_error if called on a `null` value; example: `"cannot
-    use erase() with null"`
-    @throw std::domain_error if called on an iterator which does not belong to
-    the current JSON value; example: `"iterator does not fit current value"`
-    @throw std::out_of_range if called on a primitive type with invalid
-    iterator (i.e., any iterator which is not `begin()`); example: `"iterator
-    out of range"`
-
-    @complexity The complexity depends on the type:
-    - objects: amortized constant
-    - arrays: linear in distance between pos and the end of the container
-    - strings: linear in the length of the string
-    - other types: constant
-
-    @liveexample{The example shows the result of `erase()` for different JSON
-    types.,erase__IteratorType}
-
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
-
-    @since version 1.0.0
-    */
-    template <class InteratorType, typename
-              std::enable_if<
-                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
-                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
-    InteratorType erase(InteratorType pos)
-    {
-        // make sure iterator fits the current value
-        if (this != pos.m_object)
-        {
-            throw std::domain_error("iterator does not fit current value");
-        }
-
-        InteratorType result = end();
-
-        switch (m_type)
-        {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
-            {
-                if (not pos.m_it.primitive_iterator.is_begin())
-                {
-                    throw std::out_of_range("iterator out of range");
-                }
-
-                if (is_string())
-                {
-                    AllocatorType<string_t> alloc;
-                    alloc.destroy(m_value.string);
-                    alloc.deallocate(m_value.string, 1);
-                    m_value.string = nullptr;
-                }
-
-                m_type = value_t::null;
-                assert_invariant();
-                break;
-            }
-
-            case value_t::object:
-            {
-                result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator);
-                break;
-            }
-
-            case value_t::array:
-            {
-                result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator);
-                break;
-            }
-
-            default:
-            {
-                throw std::domain_error("cannot use erase() with " + type_name());
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief remove elements given an iterator range
-
-    Removes the element specified by the range `[first; last)`. The iterator
-    @a first does not need to be dereferenceable if `first == last`: erasing
-    an empty range is a no-op.
-
-    If called on a primitive type other than `null`, the resulting JSON value
-    will be `null`.
-
-    @param[in] first iterator to the beginning of the range to remove
-    @param[in] last iterator past the end of the range to remove
-    @return Iterator following the last removed element. If the iterator @a
-    second refers to the last element, the `end()` iterator is returned.
-
-    @tparam InteratorType an @ref iterator or @ref const_iterator
-
-    @post Invalidates iterators and references at or after the point of the
-    erase, including the `end()` iterator.
-
-    @throw std::domain_error if called on a `null` value; example: `"cannot
-    use erase() with null"`
-    @throw std::domain_error if called on iterators which does not belong to
-    the current JSON value; example: `"iterators do not fit current value"`
-    @throw std::out_of_range if called on a primitive type with invalid
-    iterators (i.e., if `first != begin()` and `last != end()`); example:
-    `"iterators out of range"`
-
-    @complexity The complexity depends on the type:
-    - objects: `log(size()) + std::distance(first, last)`
-    - arrays: linear in the distance between @a first and @a last, plus linear
-      in the distance between @a last and end of the container
-    - strings: linear in the length of the string
-    - other types: constant
-
-    @liveexample{The example shows the result of `erase()` for different JSON
-    types.,erase__IteratorType_IteratorType}
-
-    @sa @ref erase(InteratorType) -- removes the element at a given position
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
-
-    @since version 1.0.0
-    */
-    template <class InteratorType, typename
-              std::enable_if<
-                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
-                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
-    InteratorType erase(InteratorType first, InteratorType last)
-    {
-        // make sure iterator fits the current value
-        if (this != first.m_object or this != last.m_object)
-        {
-            throw std::domain_error("iterators do not fit current value");
-        }
-
-        InteratorType result = end();
-
-        switch (m_type)
-        {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
-            {
-                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
-                {
-                    throw std::out_of_range("iterators out of range");
-                }
-
-                if (is_string())
-                {
-                    AllocatorType<string_t> alloc;
-                    alloc.destroy(m_value.string);
-                    alloc.deallocate(m_value.string, 1);
-                    m_value.string = nullptr;
-                }
-
-                m_type = value_t::null;
-                assert_invariant();
-                break;
-            }
-
-            case value_t::object:
-            {
-                result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator,
-                                              last.m_it.object_iterator);
-                break;
-            }
-
-            case value_t::array:
-            {
-                result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator,
-                                             last.m_it.array_iterator);
-                break;
-            }
-
-            default:
-            {
-                throw std::domain_error("cannot use erase() with " + type_name());
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief remove element from a JSON object given a key
-
-    Removes elements from a JSON object with the key value @a key.
-
-    @param[in] key value of the elements to remove
-
-    @return Number of elements removed. If @a ObjectType is the default
-    `std::map` type, the return value will always be `0` (@a key was not
-    found) or `1` (@a key was found).
-
-    @post References and iterators to the erased elements are invalidated.
-    Other references and iterators are not affected.
-
-    @throw std::domain_error when called on a type other than JSON object;
-    example: `"cannot use erase() with null"`
-
-    @complexity `log(size()) + count(key)`
-
-    @liveexample{The example shows the effect of `erase()`.,erase__key_type}
-
-    @sa @ref erase(InteratorType) -- removes the element at a given position
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
-
-    @since version 1.0.0
-    */
-    size_type erase(const typename object_t::key_type& key)
-    {
-        // this erase only works for objects
-        if (is_object())
-        {
-            return m_value.object->erase(key);
-        }
-        else
-        {
-            throw std::domain_error("cannot use erase() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief remove element from a JSON array given an index
-
-    Removes element from a JSON array at the index @a idx.
-
-    @param[in] idx index of the element to remove
-
-    @throw std::domain_error when called on a type other than JSON array;
-    example: `"cannot use erase() with null"`
-    @throw std::out_of_range when `idx >= size()`; example: `"array index 17
-    is out of range"`
-
-    @complexity Linear in distance between @a idx and the end of the container.
-
-    @liveexample{The example shows the effect of `erase()`.,erase__size_type}
-
-    @sa @ref erase(InteratorType) -- removes the element at a given position
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-
-    @since version 1.0.0
-    */
-    void erase(const size_type idx)
-    {
-        // this erase only works for arrays
-        if (is_array())
-        {
-            if (idx >= size())
-            {
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
-            }
-
-            m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
-        }
-        else
-        {
-            throw std::domain_error("cannot use erase() with " + type_name());
-        }
-    }
-
-    /// @}
-
-
-    ////////////
-    // lookup //
-    ////////////
-
-    /// @name lookup
-    /// @{
-
-    /*!
-    @brief find an element in a JSON object
-
-    Finds an element in a JSON object with key equivalent to @a key. If the
-    element is not found or the JSON value is not an object, end() is
-    returned.
-
-    @param[in] key key value of the element to search for
-
-    @return Iterator to an element with key equivalent to @a key. If no such
-    element is found, past-the-end (see end()) iterator is returned.
-
-    @complexity Logarithmic in the size of the JSON object.
-
-    @liveexample{The example shows how `find()` is used.,find__key_type}
-
-    @since version 1.0.0
-    */
-    iterator find(typename object_t::key_type key)
-    {
-        auto result = end();
-
-        if (is_object())
-        {
-            result.m_it.object_iterator = m_value.object->find(key);
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief find an element in a JSON object
-    @copydoc find(typename object_t::key_type)
-    */
-    const_iterator find(typename object_t::key_type key) const
-    {
-        auto result = cend();
-
-        if (is_object())
-        {
-            result.m_it.object_iterator = m_value.object->find(key);
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief returns the number of occurrences of a key in a JSON object
-
-    Returns the number of elements with key @a key. If ObjectType is the
-    default `std::map` type, the return value will always be `0` (@a key was
-    not found) or `1` (@a key was found).
-
-    @param[in] key key value of the element to count
-
-    @return Number of elements with key @a key. If the JSON value is not an
-    object, the return value will be `0`.
-
-    @complexity Logarithmic in the size of the JSON object.
-
-    @liveexample{The example shows how `count()` is used.,count}
-
-    @since version 1.0.0
-    */
-    size_type count(typename object_t::key_type key) const
-    {
-        // return 0 for all nonobject types
-        return is_object() ? m_value.object->count(key) : 0;
-    }
-
-    /// @}
-
-
-    ///////////////
-    // iterators //
-    ///////////////
-
-    /// @name iterators
-    /// @{
-
-    /*!
-    @brief returns an iterator to the first element
-
-    Returns an iterator to the first element.
-
-    @image html range-begin-end.svg "Illustration from cppreference.com"
-
-    @return iterator to the first element
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-
-    @liveexample{The following code shows an example for `begin()`.,begin}
-
-    @sa @ref cbegin() -- returns a const iterator to the beginning
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref cend() -- returns a const iterator to the end
-
-    @since version 1.0.0
-    */
-    iterator begin() noexcept
-    {
-        iterator result(this);
-        result.set_begin();
-        return result;
-    }
-
-    /*!
-    @copydoc basic_json::cbegin()
-    */
-    const_iterator begin() const noexcept
-    {
-        return cbegin();
-    }
-
-    /*!
-    @brief returns a const iterator to the first element
-
-    Returns a const iterator to the first element.
-
-    @image html range-begin-end.svg "Illustration from cppreference.com"
-
-    @return const iterator to the first element
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).begin()`.
-
-    @liveexample{The following code shows an example for `cbegin()`.,cbegin}
-
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref cend() -- returns a const iterator to the end
-
-    @since version 1.0.0
-    */
-    const_iterator cbegin() const noexcept
-    {
-        const_iterator result(this);
-        result.set_begin();
-        return result;
-    }
-
-    /*!
-    @brief returns an iterator to one past the last element
-
-    Returns an iterator to one past the last element.
-
-    @image html range-begin-end.svg "Illustration from cppreference.com"
-
-    @return iterator one past the last element
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-
-    @liveexample{The following code shows an example for `end()`.,end}
-
-    @sa @ref cend() -- returns a const iterator to the end
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref cbegin() -- returns a const iterator to the beginning
-
-    @since version 1.0.0
-    */
-    iterator end() noexcept
-    {
-        iterator result(this);
-        result.set_end();
-        return result;
-    }
-
-    /*!
-    @copydoc basic_json::cend()
-    */
-    const_iterator end() const noexcept
-    {
-        return cend();
-    }
-
-    /*!
-    @brief returns a const iterator to one past the last element
-
-    Returns a const iterator to one past the last element.
-
-    @image html range-begin-end.svg "Illustration from cppreference.com"
-
-    @return const iterator one past the last element
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).end()`.
-
-    @liveexample{The following code shows an example for `cend()`.,cend}
-
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref cbegin() -- returns a const iterator to the beginning
-
-    @since version 1.0.0
-    */
-    const_iterator cend() const noexcept
-    {
-        const_iterator result(this);
-        result.set_end();
-        return result;
-    }
-
-    /*!
-    @brief returns an iterator to the reverse-beginning
-
-    Returns an iterator to the reverse-beginning; that is, the last element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `reverse_iterator(end())`.
-
-    @liveexample{The following code shows an example for `rbegin()`.,rbegin}
-
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref crend() -- returns a const reverse iterator to the end
-
-    @since version 1.0.0
-    */
-    reverse_iterator rbegin() noexcept
-    {
-        return reverse_iterator(end());
-    }
-
-    /*!
-    @copydoc basic_json::crbegin()
-    */
-    const_reverse_iterator rbegin() const noexcept
-    {
-        return crbegin();
-    }
-
-    /*!
-    @brief returns an iterator to the reverse-end
-
-    Returns an iterator to the reverse-end; that is, one before the first
-    element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `reverse_iterator(begin())`.
-
-    @liveexample{The following code shows an example for `rend()`.,rend}
-
-    @sa @ref crend() -- returns a const reverse iterator to the end
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
-
-    @since version 1.0.0
-    */
-    reverse_iterator rend() noexcept
-    {
-        return reverse_iterator(begin());
-    }
-
-    /*!
-    @copydoc basic_json::crend()
-    */
-    const_reverse_iterator rend() const noexcept
-    {
-        return crend();
-    }
-
-    /*!
-    @brief returns a const reverse iterator to the last element
-
-    Returns a const iterator to the reverse-beginning; that is, the last
-    element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).rbegin()`.
-
-    @liveexample{The following code shows an example for `crbegin()`.,crbegin}
-
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref crend() -- returns a const reverse iterator to the end
-
-    @since version 1.0.0
-    */
-    const_reverse_iterator crbegin() const noexcept
-    {
-        return const_reverse_iterator(cend());
-    }
-
-    /*!
-    @brief returns a const reverse iterator to one before the first
-
-    Returns a const reverse iterator to the reverse-end; that is, one before
-    the first element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).rend()`.
-
-    @liveexample{The following code shows an example for `crend()`.,crend}
-
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
-
-    @since version 1.0.0
-    */
-    const_reverse_iterator crend() const noexcept
-    {
-        return const_reverse_iterator(cbegin());
-    }
-
-  private:
-    // forward declaration
-    template<typename IteratorType> class iteration_proxy;
-
-  public:
-    /*!
-    @brief wrapper to access iterator member functions in range-based for
-
-    This function allows to access @ref iterator::key() and @ref
-    iterator::value() during range-based for loops. In these loops, a
-    reference to the JSON values is returned, so there is no access to the
-    underlying iterator.
-
-    @note The name of this function is not yet final and may change in the
-    future.
-    */
-    static iteration_proxy<iterator> iterator_wrapper(reference cont)
-    {
-        return iteration_proxy<iterator>(cont);
-    }
-
-    /*!
-    @copydoc iterator_wrapper(reference)
-    */
-    static iteration_proxy<const_iterator> iterator_wrapper(const_reference cont)
-    {
-        return iteration_proxy<const_iterator>(cont);
-    }
-
-    /// @}
-
-
-    //////////////
-    // capacity //
-    //////////////
-
-    /// @name capacity
-    /// @{
-
-    /*!
-    @brief checks whether the container is empty
-
-    Checks if a JSON value has no elements.
-
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `true`
-            boolean     | `false`
-            string      | `false`
-            number      | `false`
-            object      | result of function `object_t::empty()`
-            array       | result of function `array_t::empty()`
-
-    @note This function does not return whether a string stored as JSON value
-    is empty - it returns whether the JSON container itself is empty which is
-    false in the case of a string.
-
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their `empty()` functions have constant
-    complexity.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `begin() == end()`.
-
-    @liveexample{The following code uses `empty()` to check if a JSON
-    object contains any elements.,empty}
-
-    @sa @ref size() -- returns the number of elements
-
-    @since version 1.0.0
-    */
-    bool empty() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-            {
-                // null values are empty
-                return true;
-            }
-
-            case value_t::array:
-            {
-                // delegate call to array_t::empty()
-                return m_value.array->empty();
-            }
-
-            case value_t::object:
-            {
-                // delegate call to object_t::empty()
-                return m_value.object->empty();
-            }
-
-            default:
-            {
-                // all other types are nonempty
-                return false;
-            }
-        }
-    }
-
-    /*!
-    @brief returns the number of elements
-
-    Returns the number of elements in a JSON value.
-
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `0`
-            boolean     | `1`
-            string      | `1`
-            number      | `1`
-            object      | result of function object_t::size()
-            array       | result of function array_t::size()
-
-    @note This function does not return the length of a string stored as JSON
-    value - it returns the number of elements in the JSON value which is 1 in
-    the case of a string.
-
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their size() functions have constant
-    complexity.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `std::distance(begin(), end())`.
-
-    @liveexample{The following code calls `size()` on the different value
-    types.,size}
-
-    @sa @ref empty() -- checks whether the container is empty
-    @sa @ref max_size() -- returns the maximal number of elements
-
-    @since version 1.0.0
-    */
-    size_type size() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-            {
-                // null values are empty
-                return 0;
-            }
-
-            case value_t::array:
-            {
-                // delegate call to array_t::size()
-                return m_value.array->size();
-            }
-
-            case value_t::object:
-            {
-                // delegate call to object_t::size()
-                return m_value.object->size();
-            }
-
-            default:
-            {
-                // all other types have size 1
-                return 1;
-            }
-        }
-    }
-
-    /*!
-    @brief returns the maximum possible number of elements
-
-    Returns the maximum number of elements a JSON value is able to hold due to
-    system or library implementation limitations, i.e. `std::distance(begin(),
-    end())` for the JSON value.
-
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `0` (same as `size()`)
-            boolean     | `1` (same as `size()`)
-            string      | `1` (same as `size()`)
-            number      | `1` (same as `size()`)
-            object      | result of function `object_t::max_size()`
-            array       | result of function `array_t::max_size()`
-
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their `max_size()` functions have constant
-    complexity.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of returning `b.size()` where `b` is the largest
-      possible JSON value.
-
-    @liveexample{The following code calls `max_size()` on the different value
-    types. Note the output is implementation specific.,max_size}
-
-    @sa @ref size() -- returns the number of elements
-
-    @since version 1.0.0
-    */
-    size_type max_size() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::array:
-            {
-                // delegate call to array_t::max_size()
-                return m_value.array->max_size();
-            }
-
-            case value_t::object:
-            {
-                // delegate call to object_t::max_size()
-                return m_value.object->max_size();
-            }
-
-            default:
-            {
-                // all other types have max_size() == size()
-                return size();
-            }
-        }
-    }
-
-    /// @}
-
-
-    ///////////////
-    // modifiers //
-    ///////////////
-
-    /// @name modifiers
-    /// @{
-
-    /*!
-    @brief clears the contents
-
-    Clears the content of a JSON value and resets it to the default value as
-    if @ref basic_json(value_t) would have been called:
-
-    Value type  | initial value
-    ----------- | -------------
-    null        | `null`
-    boolean     | `false`
-    string      | `""`
-    number      | `0`
-    object      | `{}`
-    array       | `[]`
-
-    @note Floating-point numbers are set to `0.0` which will be serialized to
-    `0`. The vale type remains @ref number_float_t.
-
-    @complexity Linear in the size of the JSON value.
-
-    @liveexample{The example below shows the effect of `clear()` to different
-    JSON types.,clear}
-
-    @since version 1.0.0
-    */
-    void clear() noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::number_integer:
-            {
-                m_value.number_integer = 0;
-                break;
-            }
-
-            case value_t::number_unsigned:
-            {
-                m_value.number_unsigned = 0;
-                break;
-            }
-
-            case value_t::number_float:
-            {
-                m_value.number_float = 0.0;
-                break;
-            }
-
-            case value_t::boolean:
-            {
-                m_value.boolean = false;
-                break;
-            }
-
-            case value_t::string:
-            {
-                m_value.string->clear();
-                break;
-            }
-
-            case value_t::array:
-            {
-                m_value.array->clear();
-                break;
-            }
-
-            case value_t::object:
-            {
-                m_value.object->clear();
-                break;
-            }
-
-            default:
-            {
-                break;
-            }
-        }
-    }
-
-    /*!
-    @brief add an object to an array
-
-    Appends the given element @a val to the end of the JSON value. If the
-    function is called on a JSON null value, an empty array is created before
-    appending @a val.
-
-    @param[in] val the value to add to the JSON array
-
-    @throw std::domain_error when called on a type other than JSON array or
-    null; example: `"cannot use push_back() with number"`
-
-    @complexity Amortized constant.
-
-    @liveexample{The example shows how `push_back()` and `+=` can be used to
-    add elements to a JSON array. Note how the `null` value was silently
-    converted to a JSON array.,push_back}
-
-    @since version 1.0.0
-    */
-    void push_back(basic_json&& val)
-    {
-        // push_back only works for null objects or arrays
-        if (not(is_null() or is_array()))
-        {
-            throw std::domain_error("cannot use push_back() with " + type_name());
-        }
-
-        // transform null object into an array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value = value_t::array;
-            assert_invariant();
-        }
-
-        // add element to array (move semantics)
-        m_value.array->push_back(std::move(val));
-        // invalidate object
-        val.m_type = value_t::null;
-    }
-
-    /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
-    */
-    reference operator+=(basic_json&& val)
-    {
-        push_back(std::move(val));
-        return *this;
-    }
-
-    /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
-    */
-    void push_back(const basic_json& val)
-    {
-        // push_back only works for null objects or arrays
-        if (not(is_null() or is_array()))
-        {
-            throw std::domain_error("cannot use push_back() with " + type_name());
-        }
-
-        // transform null object into an array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value = value_t::array;
-            assert_invariant();
-        }
-
-        // add element to array
-        m_value.array->push_back(val);
-    }
-
-    /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
-    */
-    reference operator+=(const basic_json& val)
-    {
-        push_back(val);
-        return *this;
-    }
-
-    /*!
-    @brief add an object to an object
-
-    Inserts the given element @a val to the JSON object. If the function is
-    called on a JSON null value, an empty object is created before inserting
-    @a val.
-
-    @param[in] val the value to add to the JSON object
-
-    @throw std::domain_error when called on a type other than JSON object or
-    null; example: `"cannot use push_back() with number"`
-
-    @complexity Logarithmic in the size of the container, O(log(`size()`)).
-
-    @liveexample{The example shows how `push_back()` and `+=` can be used to
-    add elements to a JSON object. Note how the `null` value was silently
-    converted to a JSON object.,push_back__object_t__value}
-
-    @since version 1.0.0
-    */
-    void push_back(const typename object_t::value_type& val)
-    {
-        // push_back only works for null objects or objects
-        if (not(is_null() or is_object()))
-        {
-            throw std::domain_error("cannot use push_back() with " + type_name());
-        }
-
-        // transform null object into an object
-        if (is_null())
-        {
-            m_type = value_t::object;
-            m_value = value_t::object;
-            assert_invariant();
-        }
-
-        // add element to array
-        m_value.object->insert(val);
-    }
-
-    /*!
-    @brief add an object to an object
-    @copydoc push_back(const typename object_t::value_type&)
-    */
-    reference operator+=(const typename object_t::value_type& val)
-    {
-        push_back(val);
-        return *this;
-    }
-
-    /*!
-    @brief add an object to an object
-
-    This function allows to use `push_back` with an initializer list. In case
-
-    1. the current value is an object,
-    2. the initializer list @a init contains only two elements, and
-    3. the first element of @a init is a string,
-
-    @a init is converted into an object element and added using
-    @ref push_back(const typename object_t::value_type&). Otherwise, @a init
-    is converted to a JSON value and added using @ref push_back(basic_json&&).
-
-    @param init  an initializer list
-
-    @complexity Linear in the size of the initializer list @a init.
-
-    @note This function is required to resolve an ambiguous overload error,
-          because pairs like `{"key", "value"}` can be both interpreted as
-          `object_t::value_type` or `std::initializer_list<basic_json>`, see
-          https://github.com/nlohmann/json/issues/235 for more information.
-
-    @liveexample{The example shows how initializer lists are treated as
-    objects when possible.,push_back__initializer_list}
-    */
-    void push_back(std::initializer_list<basic_json> init)
-    {
-        if (is_object() and init.size() == 2 and init.begin()->is_string())
-        {
-            const string_t key = *init.begin();
-            push_back(typename object_t::value_type(key, *(init.begin() + 1)));
-        }
-        else
-        {
-            push_back(basic_json(init));
-        }
-    }
-
-    /*!
-    @brief add an object to an object
-    @copydoc push_back(std::initializer_list<basic_json>)
-    */
-    reference operator+=(std::initializer_list<basic_json> init)
-    {
-        push_back(init);
-        return *this;
-    }
-
-    /*!
-    @brief inserts element
-
-    Inserts element @a val before iterator @a pos.
-
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] val element to insert
-    @return iterator pointing to the inserted @a val.
-
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-
-    @complexity Constant plus linear in the distance between pos and end of the
-    container.
-
-    @liveexample{The example shows how `insert()` is used.,insert}
-
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, const basic_json& val)
-    {
-        // insert only works for arrays
-        if (is_array())
-        {
-            // check if iterator pos fits to this JSON value
-            if (pos.m_object != this)
-            {
-                throw std::domain_error("iterator does not fit current value");
-            }
-
-            // insert to array and return iterator
-            iterator result(this);
-            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
-            return result;
-        }
-        else
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief inserts element
-    @copydoc insert(const_iterator, const basic_json&)
-    */
-    iterator insert(const_iterator pos, basic_json&& val)
-    {
-        return insert(pos, val);
-    }
-
-    /*!
-    @brief inserts elements
-
-    Inserts @a cnt copies of @a val before iterator @a pos.
-
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] cnt number of copies of @a val to insert
-    @param[in] val element to insert
-    @return iterator pointing to the first element inserted, or @a pos if
-    `cnt==0`
-
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-
-    @complexity Linear in @a cnt plus linear in the distance between @a pos
-    and end of the container.
-
-    @liveexample{The example shows how `insert()` is used.,insert__count}
-
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, size_type cnt, const basic_json& val)
-    {
-        // insert only works for arrays
-        if (is_array())
-        {
-            // check if iterator pos fits to this JSON value
-            if (pos.m_object != this)
-            {
-                throw std::domain_error("iterator does not fit current value");
-            }
-
-            // insert to array and return iterator
-            iterator result(this);
-            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
-            return result;
-        }
-        else
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief inserts elements
-
-    Inserts elements from range `[first, last)` before iterator @a pos.
-
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] first begin of the range of elements to insert
-    @param[in] last end of the range of elements to insert
-
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-    @throw std::domain_error if @a first and @a last do not belong to the same
-    JSON value; example: `"iterators do not fit"`
-    @throw std::domain_error if @a first or @a last are iterators into
-    container for which insert is called; example: `"passed iterators may not
-    belong to container"`
-
-    @return iterator pointing to the first element inserted, or @a pos if
-    `first==last`
-
-    @complexity Linear in `std::distance(first, last)` plus linear in the
-    distance between @a pos and end of the container.
-
-    @liveexample{The example shows how `insert()` is used.,insert__range}
-
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, const_iterator first, const_iterator last)
-    {
-        // insert only works for arrays
-        if (not is_array())
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
-
-        // check if iterator pos fits to this JSON value
-        if (pos.m_object != this)
-        {
-            throw std::domain_error("iterator does not fit current value");
-        }
-
-        // check if range iterators belong to the same JSON object
-        if (first.m_object != last.m_object)
-        {
-            throw std::domain_error("iterators do not fit");
-        }
-
-        if (first.m_object == this or last.m_object == this)
-        {
-            throw std::domain_error("passed iterators may not belong to container");
-        }
-
-        // insert to array and return iterator
-        iterator result(this);
-        result.m_it.array_iterator = m_value.array->insert(
-                                         pos.m_it.array_iterator,
-                                         first.m_it.array_iterator,
-                                         last.m_it.array_iterator);
-        return result;
-    }
-
-    /*!
-    @brief inserts elements
-
-    Inserts elements from initializer list @a ilist before iterator @a pos.
-
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] ilist initializer list to insert the values from
-
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-
-    @return iterator pointing to the first element inserted, or @a pos if
-    `ilist` is empty
-
-    @complexity Linear in `ilist.size()` plus linear in the distance between
-    @a pos and end of the container.
-
-    @liveexample{The example shows how `insert()` is used.,insert__ilist}
-
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, std::initializer_list<basic_json> ilist)
-    {
-        // insert only works for arrays
-        if (not is_array())
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
-
-        // check if iterator pos fits to this JSON value
-        if (pos.m_object != this)
-        {
-            throw std::domain_error("iterator does not fit current value");
-        }
-
-        // insert to array and return iterator
-        iterator result(this);
-        result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, ilist);
-        return result;
-    }
-
-    /*!
-    @brief exchanges the values
-
-    Exchanges the contents of the JSON value with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
-
-    @param[in,out] other JSON value to exchange the contents with
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how JSON values can be swapped with
-    `swap()`.,swap__reference}
-
-    @since version 1.0.0
-    */
-    void swap(reference other) noexcept (
-        std::is_nothrow_move_constructible<value_t>::value and
-        std::is_nothrow_move_assignable<value_t>::value and
-        std::is_nothrow_move_constructible<json_value>::value and
-        std::is_nothrow_move_assignable<json_value>::value
-    )
-    {
-        std::swap(m_type, other.m_type);
-        std::swap(m_value, other.m_value);
-        assert_invariant();
-    }
-
-    /*!
-    @brief exchanges the values
-
-    Exchanges the contents of a JSON array with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
-
-    @param[in,out] other array to exchange the contents with
-
-    @throw std::domain_error when JSON value is not an array; example: `"cannot
-    use swap() with string"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how arrays can be swapped with
-    `swap()`.,swap__array_t}
-
-    @since version 1.0.0
-    */
-    void swap(array_t& other)
-    {
-        // swap only works for arrays
-        if (is_array())
-        {
-            std::swap(*(m_value.array), other);
-        }
-        else
-        {
-            throw std::domain_error("cannot use swap() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief exchanges the values
-
-    Exchanges the contents of a JSON object with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
-
-    @param[in,out] other object to exchange the contents with
-
-    @throw std::domain_error when JSON value is not an object; example:
-    `"cannot use swap() with string"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how objects can be swapped with
-    `swap()`.,swap__object_t}
-
-    @since version 1.0.0
-    */
-    void swap(object_t& other)
-    {
-        // swap only works for objects
-        if (is_object())
-        {
-            std::swap(*(m_value.object), other);
-        }
-        else
-        {
-            throw std::domain_error("cannot use swap() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief exchanges the values
-
-    Exchanges the contents of a JSON string with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
-
-    @param[in,out] other string to exchange the contents with
-
-    @throw std::domain_error when JSON value is not a string; example: `"cannot
-    use swap() with boolean"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how strings can be swapped with
-    `swap()`.,swap__string_t}
-
-    @since version 1.0.0
-    */
-    void swap(string_t& other)
-    {
-        // swap only works for strings
-        if (is_string())
-        {
-            std::swap(*(m_value.string), other);
-        }
-        else
-        {
-            throw std::domain_error("cannot use swap() with " + type_name());
-        }
-    }
-
-    /// @}
-
-
-    //////////////////////////////////////////
-    // lexicographical comparison operators //
-    //////////////////////////////////////////
-
-    /// @name lexicographical comparison operators
-    /// @{
-
-  private:
-    /*!
-    @brief comparison operator for JSON types
-
-    Returns an ordering that is similar to Python:
-    - order: null < boolean < number < object < array < string
-    - furthermore, each type is not smaller than itself
-
-    @since version 1.0.0
-    */
-    friend bool operator<(const value_t lhs, const value_t rhs) noexcept
-    {
-        static constexpr std::array<uint8_t, 8> order = {{
-                0, // null
-                3, // object
-                4, // array
-                5, // string
-                1, // boolean
-                2, // integer
-                2, // unsigned
-                2, // float
-            }
-        };
-
-        // discarded values are not comparable
-        if (lhs == value_t::discarded or rhs == value_t::discarded)
-        {
-            return false;
-        }
-
-        return order[static_cast<std::size_t>(lhs)] < order[static_cast<std::size_t>(rhs)];
-    }
-
-  public:
-    /*!
-    @brief comparison: equal
-
-    Compares two JSON values for equality according to the following rules:
-    - Two JSON values are equal if (1) they are from the same type and (2)
-      their stored values are the same.
-    - Integer and floating-point numbers are automatically converted before
-      comparison. Floating-point numbers are compared indirectly: two
-      floating-point numbers `f1` and `f2` are considered equal if neither
-      `f1 > f2` nor `f2 > f1` holds.
-    - Two JSON null values are equal.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether the values @a lhs and @a rhs are equal
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__equal}
-
-    @since version 1.0.0
-    */
-    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
-    {
-        const auto lhs_type = lhs.type();
-        const auto rhs_type = rhs.type();
-
-        if (lhs_type == rhs_type)
-        {
-            switch (lhs_type)
-            {
-                case value_t::array:
-                {
-                    return *lhs.m_value.array == *rhs.m_value.array;
-                }
-                case value_t::object:
-                {
-                    return *lhs.m_value.object == *rhs.m_value.object;
-                }
-                case value_t::null:
-                {
-                    return true;
-                }
-                case value_t::string:
-                {
-                    return *lhs.m_value.string == *rhs.m_value.string;
-                }
-                case value_t::boolean:
-                {
-                    return lhs.m_value.boolean == rhs.m_value.boolean;
-                }
-                case value_t::number_integer:
-                {
-                    return lhs.m_value.number_integer == rhs.m_value.number_integer;
-                }
-                case value_t::number_unsigned:
-                {
-                    return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned;
-                }
-                case value_t::number_float:
-                {
-                    return lhs.m_value.number_float == rhs.m_value.number_float;
-                }
-                default:
-                {
-                    return false;
-                }
-            }
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
-        {
-            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
-        {
-            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer;
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned);
-        }
-
-        return false;
-    }
-
-    /*!
-    @brief comparison: equal
-
-    The functions compares the given JSON value against a null pointer. As the
-    null pointer can be used to initialize a JSON value to null, a comparison
-    of JSON value @a v with a null pointer should be equivalent to call
-    `v.is_null()`.
-
-    @param[in] v  JSON value to consider
-    @return whether @a v is null
-
-    @complexity Constant.
-
-    @liveexample{The example compares several JSON types to the null pointer.
-    ,operator__equal__nullptr_t}
-
-    @since version 1.0.0
-    */
-    friend bool operator==(const_reference v, std::nullptr_t) noexcept
-    {
-        return v.is_null();
-    }
-
-    /*!
-    @brief comparison: equal
-    @copydoc operator==(const_reference, std::nullptr_t)
-    */
-    friend bool operator==(std::nullptr_t, const_reference v) noexcept
-    {
-        return v.is_null();
-    }
-
-    /*!
-    @brief comparison: not equal
-
-    Compares two JSON values for inequality by calculating `not (lhs == rhs)`.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether the values @a lhs and @a rhs are not equal
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__notequal}
-
-    @since version 1.0.0
-    */
-    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs == rhs);
-    }
-
-    /*!
-    @brief comparison: not equal
-
-    The functions compares the given JSON value against a null pointer. As the
-    null pointer can be used to initialize a JSON value to null, a comparison
-    of JSON value @a v with a null pointer should be equivalent to call
-    `not v.is_null()`.
-
-    @param[in] v  JSON value to consider
-    @return whether @a v is not null
-
-    @complexity Constant.
-
-    @liveexample{The example compares several JSON types to the null pointer.
-    ,operator__notequal__nullptr_t}
-
-    @since version 1.0.0
-    */
-    friend bool operator!=(const_reference v, std::nullptr_t) noexcept
-    {
-        return not v.is_null();
-    }
-
-    /*!
-    @brief comparison: not equal
-    @copydoc operator!=(const_reference, std::nullptr_t)
-    */
-    friend bool operator!=(std::nullptr_t, const_reference v) noexcept
-    {
-        return not v.is_null();
-    }
-
-    /*!
-    @brief comparison: less than
-
-    Compares whether one JSON value @a lhs is less than another JSON value @a
-    rhs according to the following rules:
-    - If @a lhs and @a rhs have the same type, the values are compared using
-      the default `<` operator.
-    - Integer and floating-point numbers are automatically converted before
-      comparison
-    - In case @a lhs and @a rhs have different types, the values are ignored
-      and the order of the types is considered, see
-      @ref operator<(const value_t, const value_t).
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is less than @a rhs
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__less}
-
-    @since version 1.0.0
-    */
-    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
-    {
-        const auto lhs_type = lhs.type();
-        const auto rhs_type = rhs.type();
-
-        if (lhs_type == rhs_type)
-        {
-            switch (lhs_type)
-            {
-                case value_t::array:
-                {
-                    return *lhs.m_value.array < *rhs.m_value.array;
-                }
-                case value_t::object:
-                {
-                    return *lhs.m_value.object < *rhs.m_value.object;
-                }
-                case value_t::null:
-                {
-                    return false;
-                }
-                case value_t::string:
-                {
-                    return *lhs.m_value.string < *rhs.m_value.string;
-                }
-                case value_t::boolean:
-                {
-                    return lhs.m_value.boolean < rhs.m_value.boolean;
-                }
-                case value_t::number_integer:
-                {
-                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
-                }
-                case value_t::number_unsigned:
-                {
-                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
-                }
-                case value_t::number_float:
-                {
-                    return lhs.m_value.number_float < rhs.m_value.number_float;
-                }
-                default:
-                {
-                    return false;
-                }
-            }
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
-        {
-            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
-        {
-            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
-        }
-
-        // We only reach this line if we cannot compare values. In that case,
-        // we compare types. Note we have to call the operator explicitly,
-        // because MSVC has problems otherwise.
-        return operator<(lhs_type, rhs_type);
-    }
-
-    /*!
-    @brief comparison: less than or equal
-
-    Compares whether one JSON value @a lhs is less than or equal to another
-    JSON value by calculating `not (rhs < lhs)`.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is less than or equal to @a rhs
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__greater}
-
-    @since version 1.0.0
-    */
-    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (rhs < lhs);
-    }
-
-    /*!
-    @brief comparison: greater than
-
-    Compares whether one JSON value @a lhs is greater than another
-    JSON value by calculating `not (lhs <= rhs)`.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is greater than to @a rhs
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__lessequal}
-
-    @since version 1.0.0
-    */
-    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs <= rhs);
-    }
-
-    /*!
-    @brief comparison: greater than or equal
-
-    Compares whether one JSON value @a lhs is greater than or equal to another
-    JSON value by calculating `not (lhs < rhs)`.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is greater than or equal to @a rhs
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__greaterequal}
-
-    @since version 1.0.0
-    */
-    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs < rhs);
-    }
-
-    /// @}
-
-
-    ///////////////////
-    // serialization //
-    ///////////////////
-
-    /// @name serialization
-    /// @{
-
-    /*!
-    @brief serialize to stream
-
-    Serialize the given JSON value @a j to the output stream @a o. The JSON
-    value will be serialized using the @ref dump member function. The
-    indentation of the output can be controlled with the member variable
-    `width` of the output stream @a o. For instance, using the manipulator
-    `std::setw(4)` on @a o sets the indentation level to `4` and the
-    serialization result is the same as calling `dump(4)`.
-
-    @note During serializaion, the locale and the precision of the output
-    stream @a o are changed. The original values are restored when the
-    function returns.
-
-    @param[in,out] o  stream to serialize to
-    @param[in] j  JSON value to serialize
-
-    @return the stream @a o
-
-    @complexity Linear.
-
-    @liveexample{The example below shows the serialization with different
-    parameters to `width` to adjust the indentation level.,operator_serialize}
-
-    @since version 1.0.0
-    */
-    friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
-    {
-        // read width member and use it as indentation parameter if nonzero
-        const bool pretty_print = (o.width() > 0);
-        const auto indentation = (pretty_print ? o.width() : 0);
-
-        // reset width to 0 for subsequent calls to this stream
-        o.width(0);
-
-        // fix locale problems
-        const auto old_locale = o.imbue(std::locale(std::locale(), new DecimalSeparator));
-        // set precision
-
-        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
-        // string->float->string, string->double->string or string->long
-        // double->string; to be safe, we read this value from
-        // std::numeric_limits<number_float_t>::digits10
-        const auto old_precision = o.precision(std::numeric_limits<double>::digits10);
-
-        // do the actual serialization
-        j.dump(o, pretty_print, static_cast<unsigned int>(indentation));
-
-        // reset locale and precision
-        o.imbue(old_locale);
-        o.precision(old_precision);
-        return o;
-    }
-
-    /*!
-    @brief serialize to stream
-    @copydoc operator<<(std::ostream&, const basic_json&)
-    */
-    friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
-    {
-        return o << j;
-    }
-
-    /// @}
-
-
-    /////////////////////
-    // deserialization //
-    /////////////////////
-
-    /// @name deserialization
-    /// @{
-
-    /*!
-    @brief deserialize from string
-
-    @param[in] s  string to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-
-    @return result of the deserialization
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below demonstrates the `parse()` function with
-    and without callback function.,parse__string__parser_callback_t}
-
-    @sa @ref parse(std::istream&, const parser_callback_t) for a version that
-    reads from an input stream
-
-    @since version 1.0.0
-    */
-    static basic_json parse(const string_t& s,
-                            const parser_callback_t cb = nullptr)
-    {
-        return parser(s, cb).parse();
-    }
-
-    /*!
-    @brief deserialize from stream
-
-    @param[in,out] i  stream to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-
-    @return result of the deserialization
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below demonstrates the `parse()` function with
-    and without callback function.,parse__istream__parser_callback_t}
-
-    @sa @ref parse(const string_t&, const parser_callback_t) for a version
-    that reads from a string
-
-    @since version 1.0.0
-    */
-    static basic_json parse(std::istream& i,
-                            const parser_callback_t cb = nullptr)
-    {
-        return parser(i, cb).parse();
-    }
-
-    /*!
-    @copydoc parse(std::istream&, const parser_callback_t)
-    */
-    static basic_json parse(std::istream&& i,
-                            const parser_callback_t cb = nullptr)
-    {
-        return parser(i, cb).parse();
-    }
-
-    /*!
-    @brief deserialize from stream
-
-    Deserializes an input stream to a JSON value.
-
-    @param[in,out] i  input stream to read a serialized JSON value from
-    @param[in,out] j  JSON value to write the deserialized input to
-
-    @throw std::invalid_argument in case of parse errors
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below shows how a JSON value is constructed by
-    reading a serialization from a stream.,operator_deserialize}
-
-    @sa parse(std::istream&, const parser_callback_t) for a variant with a
-    parser callback function to filter values while parsing
-
-    @since version 1.0.0
-    */
-    friend std::istream& operator<<(basic_json& j, std::istream& i)
-    {
-        j = parser(i).parse();
-        return i;
-    }
-
-    /*!
-    @brief deserialize from stream
-    @copydoc operator<<(basic_json&, std::istream&)
-    */
-    friend std::istream& operator>>(std::istream& i, basic_json& j)
-    {
-        j = parser(i).parse();
-        return i;
-    }
-
-    /// @}
-
-
-  private:
-    ///////////////////////////
-    // convenience functions //
-    ///////////////////////////
-
-    /*!
-    @brief return the type as string
-
-    Returns the type name as string to be used in error messages - usually to
-    indicate that a function was called on a wrong JSON type.
-
-    @return basically a string representation of a the @ref m_type member
-
-    @complexity Constant.
-
-    @since version 1.0.0
-    */
-    std::string type_name() const
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-                return "null";
-            case value_t::object:
-                return "object";
-            case value_t::array:
-                return "array";
-            case value_t::string:
-                return "string";
-            case value_t::boolean:
-                return "boolean";
-            case value_t::discarded:
-                return "discarded";
-            default:
-                return "number";
-        }
-    }
-
-    /*!
-    @brief calculates the extra space to escape a JSON string
-
-    @param[in] s  the string to escape
-    @return the number of characters required to escape string @a s
-
-    @complexity Linear in the length of string @a s.
-    */
-    static std::size_t extra_space(const string_t& s) noexcept
-    {
-        return std::accumulate(s.begin(), s.end(), size_t{},
-                               [](size_t res, typename string_t::value_type c)
-        {
-            switch (c)
-            {
-                case '"':
-                case '\\':
-                case '\b':
-                case '\f':
-                case '\n':
-                case '\r':
-                case '\t':
-                {
-                    // from c (1 byte) to \x (2 bytes)
-                    return res + 1;
-                }
-
-                default:
-                {
-                    if (c >= 0x00 and c <= 0x1f)
-                    {
-                        // from c (1 byte) to \uxxxx (6 bytes)
-                        return res + 5;
-                    }
-                    else
-                    {
-                        return res;
-                    }
-                }
-            }
-        });
-    }
-
-    /*!
-    @brief escape a string
-
-    Escape a string by replacing certain special characters by a sequence of
-    an escape character (backslash) and another character and other control
-    characters by a sequence of "\u" followed by a four-digit hex
-    representation.
-
-    @param[in] s  the string to escape
-    @return  the escaped string
-
-    @complexity Linear in the length of string @a s.
-    */
-    static string_t escape_string(const string_t& s)
-    {
-        const auto space = extra_space(s);
-        if (space == 0)
-        {
-            return s;
-        }
-
-        // create a result string of necessary size
-        string_t result(s.size() + space, '\\');
-        std::size_t pos = 0;
-
-        for (const auto& c : s)
-        {
-            switch (c)
-            {
-                // quotation mark (0x22)
-                case '"':
-                {
-                    result[pos + 1] = '"';
-                    pos += 2;
-                    break;
-                }
-
-                // reverse solidus (0x5c)
-                case '\\':
-                {
-                    // nothing to change
-                    pos += 2;
-                    break;
-                }
-
-                // backspace (0x08)
-                case '\b':
-                {
-                    result[pos + 1] = 'b';
-                    pos += 2;
-                    break;
-                }
-
-                // formfeed (0x0c)
-                case '\f':
-                {
-                    result[pos + 1] = 'f';
-                    pos += 2;
-                    break;
-                }
-
-                // newline (0x0a)
-                case '\n':
-                {
-                    result[pos + 1] = 'n';
-                    pos += 2;
-                    break;
-                }
-
-                // carriage return (0x0d)
-                case '\r':
-                {
-                    result[pos + 1] = 'r';
-                    pos += 2;
-                    break;
-                }
-
-                // horizontal tab (0x09)
-                case '\t':
-                {
-                    result[pos + 1] = 't';
-                    pos += 2;
-                    break;
-                }
-
-                default:
-                {
-                    if (c >= 0x00 and c <= 0x1f)
-                    {
-                        // convert a number 0..15 to its hex representation
-                        // (0..f)
-                        static const char hexify[16] =
-                        {
-                            '0', '1', '2', '3', '4', '5', '6', '7',
-                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
-                        };
-
-                        // print character c as \uxxxx
-                        for (const char m :
-                    { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f]
-                        })
-                        {
-                            result[++pos] = m;
-                        }
-
-                        ++pos;
-                    }
-                    else
-                    {
-                        // all other characters are added as-is
-                        result[pos++] = c;
-                    }
-                    break;
-                }
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief internal implementation of the serialization function
-
-    This function is called by the public member function dump and organizes
-    the serialization internally. The indentation level is propagated as
-    additional parameter. In case of arrays and objects, the function is
-    called recursively. Note that
-
-    - strings and object keys are escaped using `escape_string()`
-    - integer numbers are converted implicitly via `operator<<`
-    - floating-point numbers are converted to a string using `"%g"` format
-
-    @param[out] o              stream to write to
-    @param[in] pretty_print    whether the output shall be pretty-printed
-    @param[in] indent_step     the indent level
-    @param[in] current_indent  the current indent level (only used internally)
-    */
-    void dump(std::ostream& o,
-              const bool pretty_print,
-              const unsigned int indent_step,
-              const unsigned int current_indent = 0) const
-    {
-        // variable to hold indentation for recursive calls
-        unsigned int new_indent = current_indent;
-
-        switch (m_type)
-        {
-            case value_t::object:
-            {
-                if (m_value.object->empty())
-                {
-                    o << "{}";
-                    return;
-                }
-
-                o << "{";
-
-                // increase indentation
-                if (pretty_print)
-                {
-                    new_indent += indent_step;
-                    o << "\n";
-                }
-
-                for (auto i = m_value.object->cbegin(); i != m_value.object->cend(); ++i)
-                {
-                    if (i != m_value.object->cbegin())
-                    {
-                        o << (pretty_print ? ",\n" : ",");
-                    }
-                    o << string_t(new_indent, ' ') << "\""
-                      << escape_string(i->first) << "\":"
-                      << (pretty_print ? " " : "");
-                    i->second.dump(o, pretty_print, indent_step, new_indent);
-                }
-
-                // decrease indentation
-                if (pretty_print)
-                {
-                    new_indent -= indent_step;
-                    o << "\n";
-                }
-
-                o << string_t(new_indent, ' ') + "}";
-                return;
-            }
-
-            case value_t::array:
-            {
-                if (m_value.array->empty())
-                {
-                    o << "[]";
-                    return;
-                }
-
-                o << "[";
-
-                // increase indentation
-                if (pretty_print)
-                {
-                    new_indent += indent_step;
-                    o << "\n";
-                }
-
-                for (auto i = m_value.array->cbegin(); i != m_value.array->cend(); ++i)
-                {
-                    if (i != m_value.array->cbegin())
-                    {
-                        o << (pretty_print ? ",\n" : ",");
-                    }
-                    o << string_t(new_indent, ' ');
-                    i->dump(o, pretty_print, indent_step, new_indent);
-                }
-
-                // decrease indentation
-                if (pretty_print)
-                {
-                    new_indent -= indent_step;
-                    o << "\n";
-                }
-
-                o << string_t(new_indent, ' ') << "]";
-                return;
-            }
-
-            case value_t::string:
-            {
-                o << string_t("\"") << escape_string(*m_value.string) << "\"";
-                return;
-            }
-
-            case value_t::boolean:
-            {
-                o << (m_value.boolean ? "true" : "false");
-                return;
-            }
-
-            case value_t::number_integer:
-            {
-                o << m_value.number_integer;
-                return;
-            }
-
-            case value_t::number_unsigned:
-            {
-                o << m_value.number_unsigned;
-                return;
-            }
-
-            case value_t::number_float:
-            {
-                if (m_value.number_float == 0)
-                {
-                    // special case for zero to get "0.0"/"-0.0"
-                    o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
-                }
-                else
-                {
-                    o << m_value.number_float;
-                }
-                return;
-            }
-
-            case value_t::discarded:
-            {
-                o << "<discarded>";
-                return;
-            }
-
-            case value_t::null:
-            {
-                o << "null";
-                return;
-            }
-        }
-    }
-
-  private:
-    //////////////////////
-    // member variables //
-    //////////////////////
-
-    /// the type of the current element
-    value_t m_type = value_t::null;
-
-    /// the value of the current element
-    json_value m_value = {};
-
-
-  private:
-    ///////////////
-    // iterators //
-    ///////////////
-
-    /*!
-    @brief an iterator for primitive JSON types
-
-    This class models an iterator for primitive JSON types (boolean, number,
-    string). It's only purpose is to allow the iterator/const_iterator classes
-    to "iterate" over primitive values. Internally, the iterator is modeled by
-    a `difference_type` variable. Value begin_value (`0`) models the begin,
-    end_value (`1`) models past the end.
-    */
-    class primitive_iterator_t
-    {
-      public:
-        /// set iterator to a defined beginning
-        void set_begin() noexcept
-        {
-            m_it = begin_value;
-        }
-
-        /// set iterator to a defined past the end
-        void set_end() noexcept
-        {
-            m_it = end_value;
-        }
-
-        /// return whether the iterator can be dereferenced
-        constexpr bool is_begin() const noexcept
-        {
-            return (m_it == begin_value);
-        }
-
-        /// return whether the iterator is at end
-        constexpr bool is_end() const noexcept
-        {
-            return (m_it == end_value);
-        }
-
-        /// return reference to the value to change and compare
-        operator difference_type& () noexcept
-        {
-            return m_it;
-        }
-
-        /// return value to compare
-        constexpr operator difference_type () const noexcept
-        {
-            return m_it;
-        }
-
-      private:
-        static constexpr difference_type begin_value = 0;
-        static constexpr difference_type end_value = begin_value + 1;
-
-        /// iterator as signed integer type
-        difference_type m_it = std::numeric_limits<std::ptrdiff_t>::denorm_min();
-    };
-
-    /*!
-    @brief an iterator value
-
-    @note This structure could easily be a union, but MSVC currently does not
-    allow unions members with complex constructors, see
-    https://github.com/nlohmann/json/pull/105.
-    */
-    struct internal_iterator
-    {
-        /// iterator for JSON objects
-        typename object_t::iterator object_iterator;
-        /// iterator for JSON arrays
-        typename array_t::iterator array_iterator;
-        /// generic iterator for all other types
-        primitive_iterator_t primitive_iterator;
-
-        /// create an uninitialized internal_iterator
-        internal_iterator() noexcept
-            : object_iterator(), array_iterator(), primitive_iterator()
-        {}
-    };
-
-    /// proxy class for the iterator_wrapper functions
-    template<typename IteratorType>
-    class iteration_proxy
-    {
-      private:
-        /// helper class for iteration
-        class iteration_proxy_internal
-        {
-          private:
-            /// the iterator
-            IteratorType anchor;
-            /// an index for arrays (used to create key names)
-            size_t array_index = 0;
-
-          public:
-            explicit iteration_proxy_internal(IteratorType it) noexcept
-                : anchor(it)
-            {}
-
-            /// dereference operator (needed for range-based for)
-            iteration_proxy_internal& operator*()
-            {
-                return *this;
-            }
-
-            /// increment operator (needed for range-based for)
-            iteration_proxy_internal& operator++()
-            {
-                ++anchor;
-                ++array_index;
-
-                return *this;
-            }
-
-            /// inequality operator (needed for range-based for)
-            bool operator!= (const iteration_proxy_internal& o) const
-            {
-                return anchor != o.anchor;
-            }
-
-            /// return key of the iterator
-            typename basic_json::string_t key() const
-            {
-                assert(anchor.m_object != nullptr);
-
-                switch (anchor.m_object->type())
-                {
-                    // use integer array index as key
-                    case value_t::array:
-                    {
-                        return std::to_string(array_index);
-                    }
-
-                    // use key from the object
-                    case value_t::object:
-                    {
-                        return anchor.key();
-                    }
-
-                    // use an empty key for all primitive types
-                    default:
-                    {
-                        return "";
-                    }
-                }
-            }
-
-            /// return value of the iterator
-            typename IteratorType::reference value() const
-            {
-                return anchor.value();
-            }
-        };
-
-        /// the container to iterate
-        typename IteratorType::reference container;
-
-      public:
-        /// construct iteration proxy from a container
-        explicit iteration_proxy(typename IteratorType::reference cont)
-            : container(cont)
-        {}
-
-        /// return iterator begin (needed for range-based for)
-        iteration_proxy_internal begin() noexcept
-        {
-            return iteration_proxy_internal(container.begin());
-        }
-
-        /// return iterator end (needed for range-based for)
-        iteration_proxy_internal end() noexcept
-        {
-            return iteration_proxy_internal(container.end());
-        }
-    };
-
-  public:
-    /*!
-    @brief a const random access iterator for the @ref basic_json class
-
-    This class implements a const iterator for the @ref basic_json class. From
-    this class, the @ref iterator class is derived.
-
-    @note An iterator is called *initialized* when a pointer to a JSON value
-          has been set (e.g., by a constructor or a copy assignment). If the
-          iterator is default-constructed, it is *uninitialized* and most
-          methods are undefined. The library uses assertions to detect calls
-          on uninitialized iterators.
-
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
-
-    @since version 1.0.0
-    */
-    class const_iterator : public std::iterator<std::random_access_iterator_tag, const basic_json>
-    {
-        /// allow basic_json to access private members
-        friend class basic_json;
-
-      public:
-        /// the type of the values when the iterator is dereferenced
-        using value_type = typename basic_json::value_type;
-        /// a type to represent differences between iterators
-        using difference_type = typename basic_json::difference_type;
-        /// defines a pointer to the type iterated over (value_type)
-        using pointer = typename basic_json::const_pointer;
-        /// defines a reference to the type iterated over (value_type)
-        using reference = typename basic_json::const_reference;
-        /// the category of the iterator
-        using iterator_category = std::bidirectional_iterator_tag;
-
-        /// default constructor
-        const_iterator() = default;
-
-        /*!
-        @brief constructor for a given JSON instance
-        @param[in] object  pointer to a JSON object for this iterator
-        @pre object != nullptr
-        @post The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        explicit const_iterator(pointer object) noexcept
-            : m_object(object)
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = typename object_t::iterator();
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = typename array_t::iterator();
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator = primitive_iterator_t();
-                    break;
-                }
-            }
-        }
-
-        /*!
-        @brief copy constructor given a non-const iterator
-        @param[in] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
-        */
-        explicit const_iterator(const iterator& other) noexcept
-            : m_object(other.m_object)
-        {
-            if (m_object != nullptr)
-            {
-                switch (m_object->m_type)
-                {
-                    case basic_json::value_t::object:
-                    {
-                        m_it.object_iterator = other.m_it.object_iterator;
-                        break;
-                    }
-
-                    case basic_json::value_t::array:
-                    {
-                        m_it.array_iterator = other.m_it.array_iterator;
-                        break;
-                    }
-
-                    default:
-                    {
-                        m_it.primitive_iterator = other.m_it.primitive_iterator;
-                        break;
-                    }
-                }
-            }
-        }
-
-        /*!
-        @brief copy constructor
-        @param[in] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
-        */
-        const_iterator(const const_iterator& other) noexcept
-            : m_object(other.m_object), m_it(other.m_it)
-        {}
-
-        /*!
-        @brief copy assignment
-        @param[in,out] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
-        */
-        const_iterator& operator=(const_iterator other) noexcept(
-            std::is_nothrow_move_constructible<pointer>::value and
-            std::is_nothrow_move_assignable<pointer>::value and
-            std::is_nothrow_move_constructible<internal_iterator>::value and
-            std::is_nothrow_move_assignable<internal_iterator>::value
-        )
-        {
-            std::swap(m_object, other.m_object);
-            std::swap(m_it, other.m_it);
-            return *this;
-        }
-
-      private:
-        /*!
-        @brief set the iterator to the first value
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        void set_begin() noexcept
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = m_object->m_value.object->begin();
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = m_object->m_value.array->begin();
-                    break;
-                }
-
-                case basic_json::value_t::null:
-                {
-                    // set to end so begin()==end() is true: null is empty
-                    m_it.primitive_iterator.set_end();
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator.set_begin();
-                    break;
-                }
-            }
-        }
-
-        /*!
-        @brief set the iterator past the last value
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        void set_end() noexcept
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = m_object->m_value.object->end();
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = m_object->m_value.array->end();
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator.set_end();
-                    break;
-                }
-            }
-        }
-
-      public:
-        /*!
-        @brief return a reference to the value pointed to by the iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference operator*() const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    assert(m_it.object_iterator != m_object->m_value.object->end());
-                    return m_it.object_iterator->second;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    assert(m_it.array_iterator != m_object->m_value.array->end());
-                    return *m_it.array_iterator;
-                }
-
-                case basic_json::value_t::null:
-                {
-                    throw std::out_of_range("cannot get value");
-                }
-
-                default:
-                {
-                    if (m_it.primitive_iterator.is_begin())
-                    {
-                        return *m_object;
-                    }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
-                }
-            }
-        }
-
-        /*!
-        @brief dereference the iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        pointer operator->() const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    assert(m_it.object_iterator != m_object->m_value.object->end());
-                    return &(m_it.object_iterator->second);
-                }
-
-                case basic_json::value_t::array:
-                {
-                    assert(m_it.array_iterator != m_object->m_value.array->end());
-                    return &*m_it.array_iterator;
-                }
-
-                default:
-                {
-                    if (m_it.primitive_iterator.is_begin())
-                    {
-                        return m_object;
-                    }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
-                }
-            }
-        }
-
-        /*!
-        @brief post-increment (it++)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator operator++(int)
-        {
-            auto result = *this;
-            ++(*this);
-            return result;
-        }
-
-        /*!
-        @brief pre-increment (++it)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator& operator++()
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    std::advance(m_it.object_iterator, 1);
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, 1);
-                    break;
-                }
-
-                default:
-                {
-                    ++m_it.primitive_iterator;
-                    break;
-                }
-            }
-
-            return *this;
-        }
-
-        /*!
-        @brief post-decrement (it--)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator operator--(int)
-        {
-            auto result = *this;
-            --(*this);
-            return result;
-        }
-
-        /*!
-        @brief pre-decrement (--it)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator& operator--()
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    std::advance(m_it.object_iterator, -1);
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, -1);
-                    break;
-                }
-
-                default:
-                {
-                    --m_it.primitive_iterator;
-                    break;
-                }
-            }
-
-            return *this;
-        }
-
-        /*!
-        @brief  comparison: equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator==(const const_iterator& other) const
-        {
-            // if objects are not the same, the comparison is undefined
-            if (m_object != other.m_object)
-            {
-                throw std::domain_error("cannot compare iterators of different containers");
-            }
-
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    return (m_it.object_iterator == other.m_it.object_iterator);
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return (m_it.array_iterator == other.m_it.array_iterator);
-                }
-
-                default:
-                {
-                    return (m_it.primitive_iterator == other.m_it.primitive_iterator);
-                }
-            }
-        }
-
-        /*!
-        @brief  comparison: not equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator!=(const const_iterator& other) const
-        {
-            return not operator==(other);
-        }
-
-        /*!
-        @brief  comparison: smaller
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator<(const const_iterator& other) const
-        {
-            // if objects are not the same, the comparison is undefined
-            if (m_object != other.m_object)
-            {
-                throw std::domain_error("cannot compare iterators of different containers");
-            }
-
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    throw std::domain_error("cannot compare order of object iterators");
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return (m_it.array_iterator < other.m_it.array_iterator);
-                }
-
-                default:
-                {
-                    return (m_it.primitive_iterator < other.m_it.primitive_iterator);
-                }
-            }
-        }
-
-        /*!
-        @brief  comparison: less than or equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator<=(const const_iterator& other) const
-        {
-            return not other.operator < (*this);
-        }
-
-        /*!
-        @brief  comparison: greater than
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator>(const const_iterator& other) const
-        {
-            return not operator<=(other);
-        }
-
-        /*!
-        @brief  comparison: greater than or equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator>=(const const_iterator& other) const
-        {
-            return not operator<(other);
-        }
-
-        /*!
-        @brief  add to iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator& operator+=(difference_type i)
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    throw std::domain_error("cannot use offsets with object iterators");
-                }
-
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, i);
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator += i;
-                    break;
-                }
-            }
-
-            return *this;
-        }
-
-        /*!
-        @brief  subtract from iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator& operator-=(difference_type i)
-        {
-            return operator+=(-i);
-        }
-
-        /*!
-        @brief  add to iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator operator+(difference_type i)
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
-
-        /*!
-        @brief  subtract from iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator operator-(difference_type i)
-        {
-            auto result = *this;
-            result -= i;
-            return result;
-        }
-
-        /*!
-        @brief  return difference
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        difference_type operator-(const const_iterator& other) const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    throw std::domain_error("cannot use offsets with object iterators");
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return m_it.array_iterator - other.m_it.array_iterator;
-                }
-
-                default:
-                {
-                    return m_it.primitive_iterator - other.m_it.primitive_iterator;
-                }
-            }
-        }
-
-        /*!
-        @brief  access to successor
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference operator[](difference_type n) const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    throw std::domain_error("cannot use operator[] for object iterators");
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return *std::next(m_it.array_iterator, n);
-                }
-
-                case basic_json::value_t::null:
-                {
-                    throw std::out_of_range("cannot get value");
-                }
-
-                default:
-                {
-                    if (m_it.primitive_iterator == -n)
-                    {
-                        return *m_object;
-                    }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
-                }
-            }
-        }
-
-        /*!
-        @brief  return the key of an object iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        typename object_t::key_type key() const
-        {
-            assert(m_object != nullptr);
-
-            if (m_object->is_object())
-            {
-                return m_it.object_iterator->first;
-            }
-            else
-            {
-                throw std::domain_error("cannot use key() for non-object iterators");
-            }
-        }
-
-        /*!
-        @brief  return the value of an iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference value() const
-        {
-            return operator*();
-        }
-
-      private:
-        /// associated JSON instance
-        pointer m_object = nullptr;
-        /// the actual iterator of the associated instance
-        internal_iterator m_it = internal_iterator();
-    };
-
-    /*!
-    @brief a mutable random access iterator for the @ref basic_json class
-
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
-    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
-      It is possible to write to the pointed-to element.
-
-    @since version 1.0.0
-    */
-    class iterator : public const_iterator
-    {
-      public:
-        using base_iterator = const_iterator;
-        using pointer = typename basic_json::pointer;
-        using reference = typename basic_json::reference;
-
-        /// default constructor
-        iterator() = default;
-
-        /// constructor for a given JSON instance
-        explicit iterator(pointer object) noexcept
-            : base_iterator(object)
-        {}
-
-        /// copy constructor
-        iterator(const iterator& other) noexcept
-            : base_iterator(other)
-        {}
-
-        /// copy assignment
-        iterator& operator=(iterator other) noexcept(
-            std::is_nothrow_move_constructible<pointer>::value and
-            std::is_nothrow_move_assignable<pointer>::value and
-            std::is_nothrow_move_constructible<internal_iterator>::value and
-            std::is_nothrow_move_assignable<internal_iterator>::value
-        )
-        {
-            base_iterator::operator=(other);
-            return *this;
-        }
-
-        /// return a reference to the value pointed to by the iterator
-        reference operator*() const
-        {
-            return const_cast<reference>(base_iterator::operator*());
-        }
-
-        /// dereference the iterator
-        pointer operator->() const
-        {
-            return const_cast<pointer>(base_iterator::operator->());
-        }
-
-        /// post-increment (it++)
-        iterator operator++(int)
-        {
-            iterator result = *this;
-            base_iterator::operator++();
-            return result;
-        }
-
-        /// pre-increment (++it)
-        iterator& operator++()
-        {
-            base_iterator::operator++();
-            return *this;
-        }
-
-        /// post-decrement (it--)
-        iterator operator--(int)
-        {
-            iterator result = *this;
-            base_iterator::operator--();
-            return result;
-        }
-
-        /// pre-decrement (--it)
-        iterator& operator--()
-        {
-            base_iterator::operator--();
-            return *this;
-        }
-
-        /// add to iterator
-        iterator& operator+=(difference_type i)
-        {
-            base_iterator::operator+=(i);
-            return *this;
-        }
-
-        /// subtract from iterator
-        iterator& operator-=(difference_type i)
-        {
-            base_iterator::operator-=(i);
-            return *this;
-        }
-
-        /// add to iterator
-        iterator operator+(difference_type i)
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
-
-        /// subtract from iterator
-        iterator operator-(difference_type i)
-        {
-            auto result = *this;
-            result -= i;
-            return result;
-        }
-
-        /// return difference
-        difference_type operator-(const iterator& other) const
-        {
-            return base_iterator::operator-(other);
-        }
-
-        /// access to successor
-        reference operator[](difference_type n) const
-        {
-            return const_cast<reference>(base_iterator::operator[](n));
-        }
-
-        /// return the value of an iterator
-        reference value() const
-        {
-            return const_cast<reference>(base_iterator::value());
-        }
-    };
-
-    /*!
-    @brief a template for a reverse iterator class
-
-    @tparam Base the base iterator type to reverse. Valid types are @ref
-    iterator (to create @ref reverse_iterator) and @ref const_iterator (to
-    create @ref const_reverse_iterator).
-
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
-    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
-      It is possible to write to the pointed-to element (only if @a Base is
-      @ref iterator).
-
-    @since version 1.0.0
-    */
-    template<typename Base>
-    class json_reverse_iterator : public std::reverse_iterator<Base>
-    {
-      public:
-        /// shortcut to the reverse iterator adaptor
-        using base_iterator = std::reverse_iterator<Base>;
-        /// the reference type for the pointed-to element
-        using reference = typename Base::reference;
-
-        /// create reverse iterator from iterator
-        json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept
-            : base_iterator(it)
-        {}
-
-        /// create reverse iterator from base class
-        json_reverse_iterator(const base_iterator& it) noexcept
-            : base_iterator(it)
-        {}
-
-        /// post-increment (it++)
-        json_reverse_iterator operator++(int)
-        {
-            return base_iterator::operator++(1);
-        }
-
-        /// pre-increment (++it)
-        json_reverse_iterator& operator++()
-        {
-            base_iterator::operator++();
-            return *this;
-        }
-
-        /// post-decrement (it--)
-        json_reverse_iterator operator--(int)
-        {
-            return base_iterator::operator--(1);
-        }
-
-        /// pre-decrement (--it)
-        json_reverse_iterator& operator--()
-        {
-            base_iterator::operator--();
-            return *this;
-        }
-
-        /// add to iterator
-        json_reverse_iterator& operator+=(difference_type i)
-        {
-            base_iterator::operator+=(i);
-            return *this;
-        }
-
-        /// add to iterator
-        json_reverse_iterator operator+(difference_type i) const
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
-
-        /// subtract from iterator
-        json_reverse_iterator operator-(difference_type i) const
-        {
-            auto result = *this;
-            result -= i;
-            return result;
-        }
-
-        /// return difference
-        difference_type operator-(const json_reverse_iterator& other) const
-        {
-            return this->base() - other.base();
-        }
-
-        /// access to successor
-        reference operator[](difference_type n) const
-        {
-            return *(this->operator+(n));
-        }
-
-        /// return the key of an object iterator
-        typename object_t::key_type key() const
-        {
-            auto it = --this->base();
-            return it.key();
-        }
-
-        /// return the value of an iterator
-        reference value() const
-        {
-            auto it = --this->base();
-            return it.operator * ();
-        }
-    };
-
-
-  private:
-    //////////////////////
-    // lexer and parser //
-    //////////////////////
-
-    /*!
-    @brief lexical analysis
-
-    This class organizes the lexical analysis during JSON deserialization. The
-    core of it is a scanner generated by [re2c](http://re2c.org) that
-    processes a buffer and recognizes tokens according to RFC 7159.
-    */
-    class lexer
-    {
-      public:
-        /// token types for the parser
-        enum class token_type
-        {
-            uninitialized,   ///< indicating the scanner is uninitialized
-            literal_true,    ///< the `true` literal
-            literal_false,   ///< the `false` literal
-            literal_null,    ///< the `null` literal
-            value_string,    ///< a string -- use get_string() for actual value
-            value_number,    ///< a number -- use get_number() for actual value
-            begin_array,     ///< the character for array begin `[`
-            begin_object,    ///< the character for object begin `{`
-            end_array,       ///< the character for array end `]`
-            end_object,      ///< the character for object end `}`
-            name_separator,  ///< the name separator `:`
-            value_separator, ///< the value separator `,`
-            parse_error,     ///< indicating a parse error
-            end_of_input     ///< indicating the end of the input buffer
-        };
-
-        /// the char type to use in the lexer
-        using lexer_char_t = unsigned char;
-
-        /// constructor with a given buffer
-        explicit lexer(const string_t& s) noexcept
-            : m_stream(nullptr), m_buffer(s)
-        {
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
-            assert(m_content != nullptr);
-            m_start = m_cursor = m_content;
-            m_limit = m_content + s.size();
-        }
-
-        /// constructor with a given stream
-        explicit lexer(std::istream* s) noexcept
-            : m_stream(s), m_buffer()
-        {
-            assert(m_stream != nullptr);
-            std::getline(*m_stream, m_buffer);
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
-            assert(m_content != nullptr);
-            m_start = m_cursor = m_content;
-            m_limit = m_content + m_buffer.size();
-        }
-
-        /// default constructor
-        lexer() = default;
-
-        // switch off unwanted functions
-        lexer(const lexer&) = delete;
-        lexer operator=(const lexer&) = delete;
-
-        /*!
-        @brief create a string from one or two Unicode code points
-
-        There are two cases: (1) @a codepoint1 is in the Basic Multilingual
-        Plane (U+0000 through U+FFFF) and @a codepoint2 is 0, or (2)
-        @a codepoint1 and @a codepoint2 are a UTF-16 surrogate pair to
-        represent a code point above U+FFFF.
-
-        @param[in] codepoint1  the code point (can be high surrogate)
-        @param[in] codepoint2  the code point (can be low surrogate or 0)
-
-        @return string representation of the code point; the length of the
-        result string is between 1 and 4 characters.
-
-        @throw std::out_of_range if code point is > 0x10ffff; example: `"code
-        points above 0x10FFFF are invalid"`
-        @throw std::invalid_argument if the low surrogate is invalid; example:
-        `""missing or wrong low surrogate""`
-
-        @complexity Constant.
-
-        @see <http://en.wikipedia.org/wiki/UTF-8#Sample_code>
-        */
-        static string_t to_unicode(const std::size_t codepoint1,
-                                   const std::size_t codepoint2 = 0)
-        {
-            // calculate the code point from the given code points
-            std::size_t codepoint = codepoint1;
-
-            // check if codepoint1 is a high surrogate
-            if (codepoint1 >= 0xD800 and codepoint1 <= 0xDBFF)
-            {
-                // check if codepoint2 is a low surrogate
-                if (codepoint2 >= 0xDC00 and codepoint2 <= 0xDFFF)
-                {
-                    codepoint =
-                        // high surrogate occupies the most significant 22 bits
-                        (codepoint1 << 10)
-                        // low surrogate occupies the least significant 15 bits
-                        + codepoint2
-                        // there is still the 0xD800, 0xDC00 and 0x10000 noise
-                        // in the result so we have to subtract with:
-                        // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
-                        - 0x35FDC00;
-                }
-                else
-                {
-                    throw std::invalid_argument("missing or wrong low surrogate");
-                }
-            }
-
-            string_t result;
-
-            if (codepoint < 0x80)
-            {
-                // 1-byte characters: 0xxxxxxx (ASCII)
-                result.append(1, static_cast<typename string_t::value_type>(codepoint));
-            }
-            else if (codepoint <= 0x7ff)
-            {
-                // 2-byte characters: 110xxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xC0 | ((codepoint >> 6) & 0x1F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else if (codepoint <= 0xffff)
-            {
-                // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xE0 | ((codepoint >> 12) & 0x0F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else if (codepoint <= 0x10ffff)
-            {
-                // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xF0 | ((codepoint >> 18) & 0x07)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 12) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else
-            {
-                throw std::out_of_range("code points above 0x10FFFF are invalid");
-            }
-
-            return result;
-        }
-
-        /// return name of values of type token_type (only used for errors)
-        static std::string token_type_name(const token_type t)
-        {
-            switch (t)
-            {
-                case token_type::uninitialized:
-                    return "<uninitialized>";
-                case token_type::literal_true:
-                    return "true literal";
-                case token_type::literal_false:
-                    return "false literal";
-                case token_type::literal_null:
-                    return "null literal";
-                case token_type::value_string:
-                    return "string literal";
-                case token_type::value_number:
-                    return "number literal";
-                case token_type::begin_array:
-                    return "'['";
-                case token_type::begin_object:
-                    return "'{'";
-                case token_type::end_array:
-                    return "']'";
-                case token_type::end_object:
-                    return "'}'";
-                case token_type::name_separator:
-                    return "':'";
-                case token_type::value_separator:
-                    return "','";
-                case token_type::parse_error:
-                    return "<parse error>";
-                case token_type::end_of_input:
-                    return "end of input";
-                default:
-                {
-                    // catch non-enum values
-                    return "unknown token"; // LCOV_EXCL_LINE
-                }
-            }
-        }
-
-        /*!
-        This function implements a scanner for JSON. It is specified using
-        regular expressions that try to follow RFC 7159 as close as possible.
-        These regular expressions are then translated into a minimized
-        deterministic finite automaton (DFA) by the tool
-        [re2c](http://re2c.org). As a result, the translated code for this
-        function consists of a large block of code with `goto` jumps.
-
-        @return the class of the next token read from the buffer
-
-        @complexity Linear in the length of the input.\n
-
-        Proposition: The loop below will always terminate for finite input.\n
-
-        Proof (by contradiction): Assume a finite input. To loop forever, the
-        loop must never hit code with a `break` statement. The only code
-        snippets without a `break` statement are the continue statements for
-        whitespace and byte-order-marks. To loop forever, the input must be an
-        infinite sequence of whitespace or byte-order-marks. This contradicts
-        the assumption of finite input, q.e.d.
-        */
-        token_type scan() noexcept
-        {
-            while (true)
-            {
-                // pointer for backtracking information
-                m_marker = nullptr;
-
-                // remember the begin of the token
-                m_start = m_cursor;
-                assert(m_start != nullptr);
-
-
-                {
-                    lexer_char_t yych;
-                    unsigned int yyaccept = 0;
-                    static const unsigned char yybm[] =
-                    {
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,  32,  32,   0,   0,  32,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        160, 128,   0, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        192, 192, 192, 192, 192, 192, 192, 192,
-                        192, 192, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128,   0, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                    };
-                    if ((m_limit - m_cursor) < 5)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 32)
-                    {
-                        goto basic_json_parser_6;
-                    }
-                    if (yych <= '\\')
-                    {
-                        if (yych <= '-')
-                        {
-                            if (yych <= '"')
-                            {
-                                if (yych <= 0x00)
-                                {
-                                    goto basic_json_parser_2;
-                                }
-                                if (yych <= '!')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_9;
-                            }
-                            else
-                            {
-                                if (yych <= '+')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                if (yych <= ',')
-                                {
-                                    goto basic_json_parser_10;
-                                }
-                                goto basic_json_parser_12;
-                            }
-                        }
-                        else
-                        {
-                            if (yych <= '9')
-                            {
-                                if (yych <= '/')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                if (yych <= '0')
-                                {
-                                    goto basic_json_parser_13;
-                                }
-                                goto basic_json_parser_15;
-                            }
-                            else
-                            {
-                                if (yych <= ':')
-                                {
-                                    goto basic_json_parser_17;
-                                }
-                                if (yych == '[')
-                                {
-                                    goto basic_json_parser_19;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 't')
-                        {
-                            if (yych <= 'f')
-                            {
-                                if (yych <= ']')
-                                {
-                                    goto basic_json_parser_21;
-                                }
-                                if (yych <= 'e')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_23;
-                            }
-                            else
-                            {
-                                if (yych == 'n')
-                                {
-                                    goto basic_json_parser_24;
-                                }
-                                if (yych <= 's')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_25;
-                            }
-                        }
-                        else
-                        {
-                            if (yych <= '|')
-                            {
-                                if (yych == '{')
-                                {
-                                    goto basic_json_parser_26;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                            else
-                            {
-                                if (yych <= '}')
-                                {
-                                    goto basic_json_parser_28;
-                                }
-                                if (yych == 0xEF)
-                                {
-                                    goto basic_json_parser_30;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                        }
-                    }
-basic_json_parser_2:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_of_input;
-                        break;
-                    }
-basic_json_parser_4:
-                    ++m_cursor;
-basic_json_parser_5:
-                    {
-                        last_token_type = token_type::parse_error;
-                        break;
-                    }
-basic_json_parser_6:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 32)
-                    {
-                        goto basic_json_parser_6;
-                    }
-                    {
-                        continue;
-                    }
-basic_json_parser_9:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych <= 0x1F)
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_10:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::value_separator;
-                        break;
-                    }
-basic_json_parser_12:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    if (yych <= '0')
-                    {
-                        goto basic_json_parser_13;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_15;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_13:
-                    yyaccept = 1;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych <= 'D')
-                    {
-                        if (yych == '.')
-                        {
-                            goto basic_json_parser_37;
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        if (yych == 'e')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                    }
-basic_json_parser_14:
-                    {
-                        last_token_type = token_type::value_number;
-                        break;
-                    }
-basic_json_parser_15:
-                    yyaccept = 1;
-                    m_marker = ++m_cursor;
-                    if ((m_limit - m_cursor) < 3)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 64)
-                    {
-                        goto basic_json_parser_15;
-                    }
-                    if (yych <= 'D')
-                    {
-                        if (yych == '.')
-                        {
-                            goto basic_json_parser_37;
-                        }
-                        goto basic_json_parser_14;
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        if (yych == 'e')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        goto basic_json_parser_14;
-                    }
-basic_json_parser_17:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::name_separator;
-                        break;
-                    }
-basic_json_parser_19:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::begin_array;
-                        break;
-                    }
-basic_json_parser_21:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_array;
-                        break;
-                    }
-basic_json_parser_23:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'a')
-                    {
-                        goto basic_json_parser_39;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_24:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'u')
-                    {
-                        goto basic_json_parser_40;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_25:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'r')
-                    {
-                        goto basic_json_parser_41;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_26:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::begin_object;
-                        break;
-                    }
-basic_json_parser_28:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_object;
-                        break;
-                    }
-basic_json_parser_30:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 0xBB)
-                    {
-                        goto basic_json_parser_42;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_31:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-basic_json_parser_32:
-                    if (yybm[0 + yych] & 128)
-                    {
-                        goto basic_json_parser_31;
-                    }
-                    if (yych <= 0x1F)
-                    {
-                        goto basic_json_parser_33;
-                    }
-                    if (yych <= '"')
-                    {
-                        goto basic_json_parser_34;
-                    }
-                    goto basic_json_parser_36;
-basic_json_parser_33:
-                    m_cursor = m_marker;
-                    if (yyaccept == 0)
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    else
-                    {
-                        goto basic_json_parser_14;
-                    }
-basic_json_parser_34:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::value_string;
-                        break;
-                    }
-basic_json_parser_36:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 'e')
-                    {
-                        if (yych <= '/')
-                        {
-                            if (yych == '"')
-                            {
-                                goto basic_json_parser_31;
-                            }
-                            if (yych <= '.')
-                            {
-                                goto basic_json_parser_33;
-                            }
-                            goto basic_json_parser_31;
-                        }
-                        else
-                        {
-                            if (yych <= '\\')
-                            {
-                                if (yych <= '[')
-                                {
-                                    goto basic_json_parser_33;
-                                }
-                                goto basic_json_parser_31;
-                            }
-                            else
-                            {
-                                if (yych == 'b')
-                                {
-                                    goto basic_json_parser_31;
-                                }
-                                goto basic_json_parser_33;
-                            }
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'q')
-                        {
-                            if (yych <= 'f')
-                            {
-                                goto basic_json_parser_31;
-                            }
-                            if (yych == 'n')
-                            {
-                                goto basic_json_parser_31;
-                            }
-                            goto basic_json_parser_33;
-                        }
-                        else
-                        {
-                            if (yych <= 's')
-                            {
-                                if (yych <= 'r')
-                                {
-                                    goto basic_json_parser_31;
-                                }
-                                goto basic_json_parser_33;
-                            }
-                            else
-                            {
-                                if (yych <= 't')
-                                {
-                                    goto basic_json_parser_31;
-                                }
-                                if (yych <= 'u')
-                                {
-                                    goto basic_json_parser_43;
-                                }
-                                goto basic_json_parser_33;
-                            }
-                        }
-                    }
-basic_json_parser_37:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_33;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_44;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_38:
-                    yych = *++m_cursor;
-                    if (yych <= ',')
-                    {
-                        if (yych == '+')
-                        {
-                            goto basic_json_parser_46;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= '-')
-                        {
-                            goto basic_json_parser_46;
-                        }
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_47;
-                        }
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_39:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_49;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_40:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_50;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_41:
-                    yych = *++m_cursor;
-                    if (yych == 'u')
-                    {
-                        goto basic_json_parser_51;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_42:
-                    yych = *++m_cursor;
-                    if (yych == 0xBF)
-                    {
-                        goto basic_json_parser_52;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_43:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_54;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_54;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_54;
-                        }
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_44:
-                    yyaccept = 1;
-                    m_marker = ++m_cursor;
-                    if ((m_limit - m_cursor) < 3)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 'D')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_14;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_44;
-                        }
-                        goto basic_json_parser_14;
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        if (yych == 'e')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        goto basic_json_parser_14;
-                    }
-basic_json_parser_46:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_33;
-                    }
-                    if (yych >= ':')
-                    {
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_47:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_14;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_47;
-                    }
-                    goto basic_json_parser_14;
-basic_json_parser_49:
-                    yych = *++m_cursor;
-                    if (yych == 's')
-                    {
-                        goto basic_json_parser_55;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_50:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_56;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_51:
-                    yych = *++m_cursor;
-                    if (yych == 'e')
-                    {
-                        goto basic_json_parser_58;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_52:
-                    ++m_cursor;
-                    {
-                        continue;
-                    }
-basic_json_parser_54:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_60;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_60;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_60;
-                        }
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_55:
-                    yych = *++m_cursor;
-                    if (yych == 'e')
-                    {
-                        goto basic_json_parser_61;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_56:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_null;
-                        break;
-                    }
-basic_json_parser_58:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_true;
-                        break;
-                    }
-basic_json_parser_60:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_63;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_63;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_63;
-                        }
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_61:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_false;
-                        break;
-                    }
-basic_json_parser_63:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_31;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_31;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_31;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                }
-
-            }
-
-            return last_token_type;
-        }
-
-        /// append data from the stream to the internal buffer
-        void yyfill() noexcept
-        {
-            if (m_stream == nullptr or not * m_stream)
-            {
-                return;
-            }
-
-            const auto offset_start = m_start - m_content;
-            const auto offset_marker = m_marker - m_start;
-            const auto offset_cursor = m_cursor - m_start;
-
-            m_buffer.erase(0, static_cast<size_t>(offset_start));
-            std::string line;
-            assert(m_stream != nullptr);
-            std::getline(*m_stream, line);
-            m_buffer += "\n" + line; // add line with newline symbol
-
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
-            assert(m_content != nullptr);
-            m_start  = m_content;
-            m_marker = m_start + offset_marker;
-            m_cursor = m_start + offset_cursor;
-            m_limit  = m_start + m_buffer.size() - 1;
-        }
-
-        /// return string representation of last read token
-        string_t get_token_string() const
-        {
-            assert(m_start != nullptr);
-            return string_t(reinterpret_cast<typename string_t::const_pointer>(m_start),
-                            static_cast<size_t>(m_cursor - m_start));
-        }
-
-        /*!
-        @brief return string value for string tokens
-
-        The function iterates the characters between the opening and closing
-        quotes of the string value. The complete string is the range
-        [m_start,m_cursor). Consequently, we iterate from m_start+1 to
-        m_cursor-1.
-
-        We differentiate two cases:
-
-        1. Escaped characters. In this case, a new character is constructed
-           according to the nature of the escape. Some escapes create new
-           characters (e.g., `"\\n"` is replaced by `"\n"`), some are copied
-           as is (e.g., `"\\\\"`). Furthermore, Unicode escapes of the shape
-           `"\\uxxxx"` need special care. In this case, to_unicode takes care
-           of the construction of the values.
-        2. Unescaped characters are copied as is.
-
-        @pre `m_cursor - m_start >= 2`, meaning the length of the last token
-        is at least 2 bytes which is trivially true for any string (which
-        consists of at least two quotes).
-
-            " c1 c2 c3 ... "
-            ^                ^
-            m_start          m_cursor
-
-        @complexity Linear in the length of the string.\n
-
-        Lemma: The loop body will always terminate.\n
-
-        Proof (by contradiction): Assume the loop body does not terminate. As
-        the loop body does not contain another loop, one of the called
-        functions must never return. The called functions are `std::strtoul`
-        and to_unicode. Neither function can loop forever, so the loop body
-        will never loop forever which contradicts the assumption that the loop
-        body does not terminate, q.e.d.\n
-
-        Lemma: The loop condition for the for loop is eventually false.\n
-
-        Proof (by contradiction): Assume the loop does not terminate. Due to
-        the above lemma, this can only be due to a tautological loop
-        condition; that is, the loop condition i < m_cursor - 1 must always be
-        true. Let x be the change of i for any loop iteration. Then
-        m_start + 1 + x < m_cursor - 1 must hold to loop indefinitely. This
-        can be rephrased to m_cursor - m_start - 2 > x. With the
-        precondition, we x <= 0, meaning that the loop condition holds
-        indefinitly if i is always decreased. However, observe that the value
-        of i is strictly increasing with each iteration, as it is incremented
-        by 1 in the iteration expression and never decremented inside the loop
-        body. Hence, the loop condition will eventually be false which
-        contradicts the assumption that the loop condition is a tautology,
-        q.e.d.
-
-        @return string value of current token without opening and closing
-        quotes
-        @throw std::out_of_range if to_unicode fails
-        */
-        string_t get_string() const
-        {
-            assert(m_cursor - m_start >= 2);
-
-            string_t result;
-            result.reserve(static_cast<size_t>(m_cursor - m_start - 2));
-
-            // iterate the result between the quotes
-            for (const lexer_char_t* i = m_start + 1; i < m_cursor - 1; ++i)
-            {
-                // process escaped characters
-                if (*i == '\\')
-                {
-                    // read next character
-                    ++i;
-
-                    switch (*i)
-                    {
-                        // the default escapes
-                        case 't':
-                        {
-                            result += "\t";
-                            break;
-                        }
-                        case 'b':
-                        {
-                            result += "\b";
-                            break;
-                        }
-                        case 'f':
-                        {
-                            result += "\f";
-                            break;
-                        }
-                        case 'n':
-                        {
-                            result += "\n";
-                            break;
-                        }
-                        case 'r':
-                        {
-                            result += "\r";
-                            break;
-                        }
-                        case '\\':
-                        {
-                            result += "\\";
-                            break;
-                        }
-                        case '/':
-                        {
-                            result += "/";
-                            break;
-                        }
-                        case '"':
-                        {
-                            result += "\"";
-                            break;
-                        }
-
-                        // unicode
-                        case 'u':
-                        {
-                            // get code xxxx from uxxxx
-                            auto codepoint = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>(i + 1),
-                                                          4).c_str(), nullptr, 16);
-
-                            // check if codepoint is a high surrogate
-                            if (codepoint >= 0xD800 and codepoint <= 0xDBFF)
-                            {
-                                // make sure there is a subsequent unicode
-                                if ((i + 6 >= m_limit) or * (i + 5) != '\\' or * (i + 6) != 'u')
-                                {
-                                    throw std::invalid_argument("missing low surrogate");
-                                }
-
-                                // get code yyyy from uxxxx\uyyyy
-                                auto codepoint2 = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>
-                                                               (i + 7), 4).c_str(), nullptr, 16);
-                                result += to_unicode(codepoint, codepoint2);
-                                // skip the next 10 characters (xxxx\uyyyy)
-                                i += 10;
-                            }
-                            else
-                            {
-                                // add unicode character(s)
-                                result += to_unicode(codepoint);
-                                // skip the next four characters (xxxx)
-                                i += 4;
-                            }
-                            break;
-                        }
-                    }
-                }
-                else
-                {
-                    // all other characters are just copied to the end of the
-                    // string
-                    result.append(1, static_cast<typename string_t::value_type>(*i));
-                }
-            }
-
-            return result;
-        }
-
-        /*!
-        @brief parse floating point number
-
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
-
-        @param[in] type  the @ref number_float_t in use
-
-        @param[in,out] endptr recieves a pointer to the first character after
-        the number
-
-        @return the floating point number
-        */
-        long double str_to_float_t(long double* /* type */, char** endptr) const
-        {
-            return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
-
-        /*!
-        @brief parse floating point number
-
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
-
-        @param[in] type  the @ref number_float_t in use
-
-        @param[in,out] endptr  recieves a pointer to the first character after
-        the number
-
-        @return the floating point number
-        */
-        double str_to_float_t(double* /* type */, char** endptr) const
-        {
-            return std::strtod(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
-
-        /*!
-        @brief parse floating point number
-
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
-
-        @param[in] type  the @ref number_float_t in use
-
-        @param[in,out] endptr  recieves a pointer to the first character after
-        the number
-
-        @return the floating point number
-        */
-        float str_to_float_t(float* /* type */, char** endptr) const
-        {
-            return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
-
-        /*!
-        @brief return number value for number tokens
-
-        This function translates the last token into the most appropriate
-        number type (either integer, unsigned integer or floating point),
-        which is passed back to the caller via the result parameter.
-
-        This function parses the integer component up to the radix point or
-        exponent while collecting information about the 'floating point
-        representation', which it stores in the result parameter. If there is
-        no radix point or exponent, and the number can fit into a @ref
-        number_integer_t or @ref number_unsigned_t then it sets the result
-        parameter accordingly.
-
-        If the number is a floating point number the number is then parsed
-        using @a std:strtod (or @a std:strtof or @a std::strtold).
-
-        @param[out] result  @ref basic_json object to receive the number, or
-        NAN if the conversion read past the current token. The latter case
-        needs to be treated by the caller function.
-        */
-        void get_number(basic_json& result) const
-        {
-            assert(m_start != nullptr);
-
-            const lexer::lexer_char_t* curptr = m_start;
-
-            // accumulate the integer conversion result (unsigned for now)
-            number_unsigned_t value = 0;
-
-            // maximum absolute value of the relevant integer type
-            number_unsigned_t max;
-
-            // temporarily store the type to avoid unecessary bitfield access
-            value_t type;
-
-            // look for sign
-            if (*curptr == '-')
-            {
-                type = value_t::number_integer;
-                max = static_cast<uint64_t>((std::numeric_limits<number_integer_t>::max)()) + 1;
-                curptr++;
-            }
-            else
-            {
-                type = value_t::number_unsigned;
-                max = static_cast<uint64_t>((std::numeric_limits<number_unsigned_t>::max)());
-            }
-
-            // count the significant figures
-            for (; curptr < m_cursor; curptr++)
-            {
-                // quickly skip tests if a digit
-                if (*curptr < '0' || *curptr > '9')
-                {
-                    if (*curptr == '.')
-                    {
-                        // don't count '.' but change to float
-                        type = value_t::number_float;
-                        continue;
-                    }
-                    // assume exponent (if not then will fail parse): change to
-                    // float, stop counting and record exponent details
-                    type = value_t::number_float;
-                    break;
-                }
-
-                // skip if definitely not an integer
-                if (type != value_t::number_float)
-                {
-                    // multiply last value by ten and add the new digit
-                    auto temp = value * 10 + *curptr - '0';
-
-                    // test for overflow
-                    if (temp < value || temp > max)
-                    {
-                        // overflow
-                        type = value_t::number_float;
-                    }
-                    else
-                    {
-                        // no overflow - save it
-                        value = temp;
-                    }
-                }
-            }
-
-            // save the value (if not a float)
-            if (type == value_t::number_unsigned)
-            {
-                result.m_value.number_unsigned = value;
-            }
-            else if (type == value_t::number_integer)
-            {
-                result.m_value.number_integer = -static_cast<number_integer_t>(value);
-            }
-            else
-            {
-                // parse with strtod
-                result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
-            }
-
-            // save the type
-            result.m_type = type;
-        }
-
-      private:
-        /// optional input stream
-        std::istream* m_stream = nullptr;
-        /// the buffer
-        string_t m_buffer;
-        /// the buffer pointer
-        const lexer_char_t* m_content = nullptr;
-        /// pointer to the beginning of the current symbol
-        const lexer_char_t* m_start = nullptr;
-        /// pointer for backtracking information
-        const lexer_char_t* m_marker = nullptr;
-        /// pointer to the current symbol
-        const lexer_char_t* m_cursor = nullptr;
-        /// pointer to the end of the buffer
-        const lexer_char_t* m_limit = nullptr;
-        /// the last token type
-        token_type last_token_type = token_type::end_of_input;
-    };
-
-    /*!
-    @brief syntax analysis
-
-    This class implements a recursive decent parser.
-    */
-    class parser
-    {
-      public:
-        /// constructor for strings
-        parser(const string_t& s, const parser_callback_t cb = nullptr) noexcept
-            : callback(cb), m_lexer(s)
-        {
-            // read first token
-            get_token();
-        }
-
-        /// a parser reading from an input stream
-        parser(std::istream& _is, const parser_callback_t cb = nullptr) noexcept
-            : callback(cb), m_lexer(&_is)
-        {
-            // read first token
-            get_token();
-        }
-
-        /// public parser interface
-        basic_json parse()
-        {
-            basic_json result = parse_internal(true);
-            result.assert_invariant();
-
-            expect(lexer::token_type::end_of_input);
-
-            // return parser result and replace it with null in case the
-            // top-level value was discarded by the callback function
-            return result.is_discarded() ? basic_json() : std::move(result);
-        }
-
-      private:
-        /// the actual parser
-        basic_json parse_internal(bool keep)
-        {
-            auto result = basic_json(value_t::discarded);
-
-            switch (last_token)
-            {
-                case lexer::token_type::begin_object:
-                {
-                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::object_start, result))))
-                    {
-                        // explicitly set result to object to cope with {}
-                        result.m_type = value_t::object;
-                        result.m_value = value_t::object;
-                    }
-
-                    // read next token
-                    get_token();
-
-                    // closing } -> we are done
-                    if (last_token == lexer::token_type::end_object)
-                    {
-                        get_token();
-                        if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
-                        {
-                            result = basic_json(value_t::discarded);
-                        }
-                        return result;
-                    }
-
-                    // no comma is expected here
-                    unexpect(lexer::token_type::value_separator);
-
-                    // otherwise: parse key-value pairs
-                    do
-                    {
-                        // ugly, but could be fixed with loop reorganization
-                        if (last_token == lexer::token_type::value_separator)
-                        {
-                            get_token();
-                        }
-
-                        // store key
-                        expect(lexer::token_type::value_string);
-                        const auto key = m_lexer.get_string();
-
-                        bool keep_tag = false;
-                        if (keep)
-                        {
-                            if (callback)
-                            {
-                                basic_json k(key);
-                                keep_tag = callback(depth, parse_event_t::key, k);
-                            }
-                            else
-                            {
-                                keep_tag = true;
-                            }
-                        }
-
-                        // parse separator (:)
-                        get_token();
-                        expect(lexer::token_type::name_separator);
-
-                        // parse and add value
-                        get_token();
-                        auto value = parse_internal(keep);
-                        if (keep and keep_tag and not value.is_discarded())
-                        {
-                            result[key] = std::move(value);
-                        }
-                    }
-                    while (last_token == lexer::token_type::value_separator);
-
-                    // closing }
-                    expect(lexer::token_type::end_object);
-                    get_token();
-                    if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
-                    {
-                        result = basic_json(value_t::discarded);
-                    }
-
-                    return result;
-                }
-
-                case lexer::token_type::begin_array:
-                {
-                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::array_start, result))))
-                    {
-                        // explicitly set result to object to cope with []
-                        result.m_type = value_t::array;
-                        result.m_value = value_t::array;
-                    }
-
-                    // read next token
-                    get_token();
-
-                    // closing ] -> we are done
-                    if (last_token == lexer::token_type::end_array)
-                    {
-                        get_token();
-                        if (callback and not callback(--depth, parse_event_t::array_end, result))
-                        {
-                            result = basic_json(value_t::discarded);
-                        }
-                        return result;
-                    }
-
-                    // no comma is expected here
-                    unexpect(lexer::token_type::value_separator);
-
-                    // otherwise: parse values
-                    do
-                    {
-                        // ugly, but could be fixed with loop reorganization
-                        if (last_token == lexer::token_type::value_separator)
-                        {
-                            get_token();
-                        }
-
-                        // parse value
-                        auto value = parse_internal(keep);
-                        if (keep and not value.is_discarded())
-                        {
-                            result.push_back(std::move(value));
-                        }
-                    }
-                    while (last_token == lexer::token_type::value_separator);
-
-                    // closing ]
-                    expect(lexer::token_type::end_array);
-                    get_token();
-                    if (keep and callback and not callback(--depth, parse_event_t::array_end, result))
-                    {
-                        result = basic_json(value_t::discarded);
-                    }
-
-                    return result;
-                }
-
-                case lexer::token_type::literal_null:
-                {
-                    get_token();
-                    result.m_type = value_t::null;
-                    break;
-                }
-
-                case lexer::token_type::value_string:
-                {
-                    const auto s = m_lexer.get_string();
-                    get_token();
-                    result = basic_json(s);
-                    break;
-                }
-
-                case lexer::token_type::literal_true:
-                {
-                    get_token();
-                    result.m_type = value_t::boolean;
-                    result.m_value = true;
-                    break;
-                }
-
-                case lexer::token_type::literal_false:
-                {
-                    get_token();
-                    result.m_type = value_t::boolean;
-                    result.m_value = false;
-                    break;
-                }
-
-                case lexer::token_type::value_number:
-                {
-                    m_lexer.get_number(result);
-                    get_token();
-                    break;
-                }
-
-                default:
-                {
-                    // the last token was unexpected
-                    unexpect(last_token);
-                }
-            }
-
-            if (keep and callback and not callback(depth, parse_event_t::value, result))
-            {
-                result = basic_json(value_t::discarded);
-            }
-            return result;
-        }
-
-        /// get next token from lexer
-        typename lexer::token_type get_token() noexcept
-        {
-            last_token = m_lexer.scan();
-            return last_token;
-        }
-
-        void expect(typename lexer::token_type t) const
-        {
-            if (t != last_token)
-            {
-                std::string error_msg = "parse error - unexpected ";
-                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
-                              "'") :
-                              lexer::token_type_name(last_token));
-                error_msg += "; expected " + lexer::token_type_name(t);
-                throw std::invalid_argument(error_msg);
-            }
-        }
-
-        void unexpect(typename lexer::token_type t) const
-        {
-            if (t == last_token)
-            {
-                std::string error_msg = "parse error - unexpected ";
-                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
-                              "'") :
-                              lexer::token_type_name(last_token));
-                throw std::invalid_argument(error_msg);
-            }
-        }
-
-      private:
-        /// current level of recursion
-        int depth = 0;
-        /// callback function
-        const parser_callback_t callback = nullptr;
-        /// the type of the last read token
-        typename lexer::token_type last_token = lexer::token_type::uninitialized;
-        /// the lexer
-        lexer m_lexer;
-    };
-
-  public:
-    /*!
-    @brief JSON Pointer
-
-    A JSON pointer defines a string syntax for identifying a specific value
-    within a JSON document. It can be used with functions `at` and
-    `operator[]`. Furthermore, JSON pointers are the base for JSON patches.
-
-    @sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
-
-    @since version 2.0.0
-    */
-    class json_pointer
-    {
-        /// allow basic_json to access private members
-        friend class basic_json;
-
-      public:
-        /*!
-        @brief create JSON pointer
-
-        Create a JSON pointer according to the syntax described in
-        [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3).
-
-        @param[in] s  string representing the JSON pointer; if omitted, the
-                      empty string is assumed which references the whole JSON
-                      value
-
-        @throw std::domain_error if reference token is nonempty and does not
-        begin with a slash (`/`); example: `"JSON pointer must be empty or
-        begin with /"`
-        @throw std::domain_error if a tilde (`~`) is not followed by `0`
-        (representing `~`) or `1` (representing `/`); example: `"escape error:
-        ~ must be followed with 0 or 1"`
-
-        @liveexample{The example shows the construction several valid JSON
-        pointers as well as the exceptional behavior.,json_pointer}
-
-        @since version 2.0.0
-        */
-        explicit json_pointer(const std::string& s = "")
-            : reference_tokens(split(s))
-        {}
-
-        /*!
-        @brief return a string representation of the JSON pointer
-
-        @invariant For each JSON pointer `ptr`, it holds:
-        @code {.cpp}
-        ptr == json_pointer(ptr.to_string());
-        @endcode
-
-        @return a string representation of the JSON pointer
-
-        @liveexample{The example shows the result of `to_string`.,
-        json_pointer__to_string}
-
-        @since version 2.0.0
-        */
-        std::string to_string() const noexcept
-        {
-            return std::accumulate(reference_tokens.begin(),
-                                   reference_tokens.end(), std::string{},
-                                   [](const std::string & a, const std::string & b)
-            {
-                return a + "/" + escape(b);
-            });
-        }
-
-        /// @copydoc to_string()
-        operator std::string() const
-        {
-            return to_string();
-        }
-
-      private:
-        /// remove and return last reference pointer
-        std::string pop_back()
-        {
-            if (is_root())
-            {
-                throw std::domain_error("JSON pointer has no parent");
-            }
-
-            auto last = reference_tokens.back();
-            reference_tokens.pop_back();
-            return last;
-        }
-
-        /// return whether pointer points to the root document
-        bool is_root() const
-        {
-            return reference_tokens.empty();
-        }
-
-        json_pointer top() const
-        {
-            if (is_root())
-            {
-                throw std::domain_error("JSON pointer has no parent");
-            }
-
-            json_pointer result = *this;
-            result.reference_tokens = {reference_tokens[0]};
-            return result;
-        }
-
-        /*!
-        @brief create and return a reference to the pointed to value
-
-        @complexity Linear in the number of reference tokens.
-        */
-        reference get_and_create(reference j) const
-        {
-            pointer result = &j;
-
-            // in case no reference tokens exist, return a reference to the
-            // JSON value j which will be overwritten by a primitive value
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (result->m_type)
-                {
-                    case value_t::null:
-                    {
-                        if (reference_token == "0")
-                        {
-                            // start a new array if reference token is 0
-                            result = &result->operator[](0);
-                        }
-                        else
-                        {
-                            // start a new object otherwise
-                            result = &result->operator[](reference_token);
-                        }
-                        break;
-                    }
-
-                    case value_t::object:
-                    {
-                        // create an entry in the object
-                        result = &result->operator[](reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        // create an entry in the array
-                        result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                        break;
-                    }
-
-                    /*
-                    The following code is only reached if there exists a
-                    reference token _and_ the current value is primitive. In
-                    this case, we have an error situation, because primitive
-                    values may only occur as single value; that is, with an
-                    empty list of reference tokens.
-                    */
-                    default:
-                    {
-                        throw std::domain_error("invalid value to unflatten");
-                    }
-                }
-            }
-
-            return *result;
-        }
-
-        /*!
-        @brief return a reference to the pointed to value
-
-        @param[in] ptr  a JSON value
-
-        @return reference to the JSON value pointed to by the JSON pointer
-
-        @complexity Linear in the length of the JSON pointer.
-
-        @throw std::out_of_range      if the JSON pointer can not be resolved
-        @throw std::domain_error      if an array index begins with '0'
-        @throw std::invalid_argument  if an array index was not a number
-        */
-        reference get_unchecked(pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // use unchecked object access
-                        ptr = &ptr->operator[](reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            throw std::domain_error("array index must not begin with '0'");
-                        }
-
-                        if (reference_token == "-")
-                        {
-                            // explicityly treat "-" as index beyond the end
-                            ptr = &ptr->operator[](ptr->m_value.array->size());
-                        }
-                        else
-                        {
-                            // convert array index to number; unchecked access
-                            ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                        }
-                        break;
-                    }
-
-                    default:
-                    {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
-                    }
-                }
-            }
-
-            return *ptr;
-        }
-
-        reference get_checked(pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // note: at performs range check
-                        ptr = &ptr->at(reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" always fails the range check
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
-                        }
-
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            throw std::domain_error("array index must not begin with '0'");
-                        }
-
-                        // note: at performs range check
-                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
-                        break;
-                    }
-
-                    default:
-                    {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
-                    }
-                }
-            }
-
-            return *ptr;
-        }
-
-        /*!
-        @brief return a const reference to the pointed to value
-
-        @param[in] ptr  a JSON value
-
-        @return const reference to the JSON value pointed to by the JSON
-                pointer
-        */
-        const_reference get_unchecked(const_pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // use unchecked object access
-                        ptr = &ptr->operator[](reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" cannot be used for const access
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
-                        }
-
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            throw std::domain_error("array index must not begin with '0'");
-                        }
-
-                        // use unchecked array access
-                        ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                        break;
-                    }
-
-                    default:
-                    {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
-                    }
-                }
-            }
-
-            return *ptr;
-        }
-
-        const_reference get_checked(const_pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // note: at performs range check
-                        ptr = &ptr->at(reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" always fails the range check
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
-                        }
-
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            throw std::domain_error("array index must not begin with '0'");
-                        }
-
-                        // note: at performs range check
-                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
-                        break;
-                    }
-
-                    default:
-                    {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
-                    }
-                }
-            }
-
-            return *ptr;
-        }
-
-        /// split the string input to reference tokens
-        static std::vector<std::string> split(std::string reference_string)
-        {
-            std::vector<std::string> result;
-
-            // special case: empty reference string -> no reference tokens
-            if (reference_string.empty())
-            {
-                return result;
-            }
-
-            // check if nonempty reference string begins with slash
-            if (reference_string[0] != '/')
-            {
-                throw std::domain_error("JSON pointer must be empty or begin with '/'");
-            }
-
-            // extract the reference tokens:
-            // - slash: position of the last read slash (or end of string)
-            // - start: position after the previous slash
-            for (
-                // search for the first slash after the first character
-                size_t slash = reference_string.find_first_of("/", 1),
-                // set the beginning of the first reference token
-                start = 1;
-                // we can stop if start == string::npos+1 = 0
-                start != 0;
-                // set the beginning of the next reference token
-                // (will eventually be 0 if slash == std::string::npos)
-                start = slash + 1,
-                // find next slash
-                slash = reference_string.find_first_of("/", start))
-            {
-                // use the text between the beginning of the reference token
-                // (start) and the last slash (slash).
-                auto reference_token = reference_string.substr(start, slash - start);
-
-                // check reference tokens are properly escaped
-                for (size_t pos = reference_token.find_first_of("~");
-                        pos != std::string::npos;
-                        pos = reference_token.find_first_of("~", pos + 1))
-                {
-                    assert(reference_token[pos] == '~');
-
-                    // ~ must be followed by 0 or 1
-                    if (pos == reference_token.size() - 1 or
-                            (reference_token[pos + 1] != '0' and
-                             reference_token[pos + 1] != '1'))
-                    {
-                        throw std::domain_error("escape error: '~' must be followed with '0' or '1'");
-                    }
-                }
-
-                // finally, store the reference token
-                unescape(reference_token);
-                result.push_back(reference_token);
-            }
-
-            return result;
-        }
-
-      private:
-        /*!
-        @brief replace all occurrences of a substring by another string
-
-        @param[in,out] s  the string to manipulate
-        @param[in]     f  the substring to replace with @a t
-        @param[in]     t  the string to replace @a f
-
-        @return The string @a s where all occurrences of @a f are replaced
-                with @a t.
-
-        @pre The search string @a f must not be empty.
-
-        @since version 2.0.0
-        */
-        static void replace_substring(std::string& s,
-                                      const std::string& f,
-                                      const std::string& t)
-        {
-            assert(not f.empty());
-
-            for (
-                size_t pos = s.find(f);         // find first occurrence of f
-                pos != std::string::npos;       // make sure f was found
-                s.replace(pos, f.size(), t),    // replace with t
-                pos = s.find(f, pos + t.size()) // find next occurrence of f
-            );
-        }
-
-        /// escape tilde and slash
-        static std::string escape(std::string s)
-        {
-            // escape "~"" to "~0" and "/" to "~1"
-            replace_substring(s, "~", "~0");
-            replace_substring(s, "/", "~1");
-            return s;
-        }
-
-        /// unescape tilde and slash
-        static void unescape(std::string& s)
-        {
-            // first transform any occurrence of the sequence '~1' to '/'
-            replace_substring(s, "~1", "/");
-            // then transform any occurrence of the sequence '~0' to '~'
-            replace_substring(s, "~0", "~");
-        }
-
-        /*!
-        @param[in] reference_string  the reference string to the current value
-        @param[in] value             the value to consider
-        @param[in,out] result        the result object to insert values to
-
-        @note Empty objects or arrays are flattened to `null`.
-        */
-        static void flatten(const std::string& reference_string,
-                            const basic_json& value,
-                            basic_json& result)
-        {
-            switch (value.m_type)
-            {
-                case value_t::array:
-                {
-                    if (value.m_value.array->empty())
-                    {
-                        // flatten empty array as null
-                        result[reference_string] = nullptr;
-                    }
-                    else
-                    {
-                        // iterate array and use index as reference string
-                        for (size_t i = 0; i < value.m_value.array->size(); ++i)
-                        {
-                            flatten(reference_string + "/" + std::to_string(i),
-                                    value.m_value.array->operator[](i), result);
-                        }
-                    }
-                    break;
-                }
-
-                case value_t::object:
-                {
-                    if (value.m_value.object->empty())
-                    {
-                        // flatten empty object as null
-                        result[reference_string] = nullptr;
-                    }
-                    else
-                    {
-                        // iterate object and use keys as reference string
-                        for (const auto& element : *value.m_value.object)
-                        {
-                            flatten(reference_string + "/" + escape(element.first),
-                                    element.second, result);
-                        }
-                    }
-                    break;
-                }
-
-                default:
-                {
-                    // add primitive value with its reference string
-                    result[reference_string] = value;
-                    break;
-                }
-            }
-        }
-
-        /*!
-        @param[in] value  flattened JSON
-
-        @return unflattened JSON
-        */
-        static basic_json unflatten(const basic_json& value)
-        {
-            if (not value.is_object())
-            {
-                throw std::domain_error("only objects can be unflattened");
-            }
-
-            basic_json result;
-
-            // iterate the JSON object values
-            for (const auto& element : *value.m_value.object)
-            {
-                if (not element.second.is_primitive())
-                {
-                    throw std::domain_error("values in object must be primitive");
-                }
-
-                // assign value to reference pointed to by JSON pointer; Note
-                // that if the JSON pointer is "" (i.e., points to the whole
-                // value), function get_and_create returns a reference to
-                // result itself. An assignment will then create a primitive
-                // value.
-                json_pointer(element.first).get_and_create(result) = element.second;
-            }
-
-            return result;
-        }
-
-      private:
-        /// the reference tokens
-        std::vector<std::string> reference_tokens {};
-    };
-
-    //////////////////////////
-    // JSON Pointer support //
-    //////////////////////////
-
-    /// @name JSON Pointer functions
-    /// @{
-
-    /*!
-    @brief access specified element via JSON Pointer
-
-    Uses a JSON pointer to retrieve a reference to the respective JSON value.
-    No bound checking is performed. Similar to @ref operator[](const typename
-    object_t::key_type&), `null` values are created in arrays and objects if
-    necessary.
-
-    In particular:
-    - If the JSON pointer points to an object key that does not exist, it
-      is created an filled with a `null` value before a reference to it
-      is returned.
-    - If the JSON pointer points to an array index that does not exist, it
-      is created an filled with a `null` value before a reference to it
-      is returned. All indices between the current maximum and the given
-      index are also filled with `null`.
-    - The special value `-` is treated as a synonym for the index past the
-      end.
-
-    @param[in] ptr  a JSON pointer
-
-    @return reference to the element pointed to by @a ptr
-
-    @complexity Constant.
-
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
-
-    @liveexample{The behavior is shown in the example.,operatorjson_pointer}
-
-    @since version 2.0.0
-    */
-    reference operator[](const json_pointer& ptr)
-    {
-        return ptr.get_unchecked(this);
-    }
-
-    /*!
-    @brief access specified element via JSON Pointer
-
-    Uses a JSON pointer to retrieve a reference to the respective JSON value.
-    No bound checking is performed. The function does not change the JSON
-    value; no `null` values are created. In particular, the the special value
-    `-` yields an exception.
-
-    @param[in] ptr  JSON pointer to the desired element
-
-    @return const reference to the element pointed to by @a ptr
-
-    @complexity Constant.
-
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
-
-    @liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
-
-    @since version 2.0.0
-    */
-    const_reference operator[](const json_pointer& ptr) const
-    {
-        return ptr.get_unchecked(this);
-    }
-
-    /*!
-    @brief access specified element via JSON Pointer
-
-    Returns a reference to the element at with specified JSON pointer @a ptr,
-    with bounds checking.
-
-    @param[in] ptr  JSON pointer to the desired element
-
-    @return reference to the element pointed to by @a ptr
-
-    @complexity Constant.
-
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
-
-    @liveexample{The behavior is shown in the example.,at_json_pointer}
-
-    @since version 2.0.0
-    */
-    reference at(const json_pointer& ptr)
-    {
-        return ptr.get_checked(this);
-    }
-
-    /*!
-    @brief access specified element via JSON Pointer
-
-    Returns a const reference to the element at with specified JSON pointer @a
-    ptr, with bounds checking.
-
-    @param[in] ptr  JSON pointer to the desired element
-
-    @return reference to the element pointed to by @a ptr
-
-    @complexity Constant.
-
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
-
-    @liveexample{The behavior is shown in the example.,at_json_pointer_const}
-
-    @since version 2.0.0
-    */
-    const_reference at(const json_pointer& ptr) const
-    {
-        return ptr.get_checked(this);
-    }
-
-    /*!
-    @brief return flattened JSON value
-
-    The function creates a JSON object whose keys are JSON pointers (see [RFC
-    6901](https://tools.ietf.org/html/rfc6901)) and whose values are all
-    primitive. The original JSON value can be restored using the @ref
-    unflatten() function.
-
-    @return an object that maps JSON pointers to primitve values
-
-    @note Empty objects and arrays are flattened to `null` and will not be
-          reconstructed correctly by the @ref unflatten() function.
-
-    @complexity Linear in the size the JSON value.
-
-    @liveexample{The following code shows how a JSON object is flattened to an
-    object whose keys consist of JSON pointers.,flatten}
-
-    @sa @ref unflatten() for the reverse function
-
-    @since version 2.0.0
-    */
-    basic_json flatten() const
-    {
-        basic_json result(value_t::object);
-        json_pointer::flatten("", *this, result);
-        return result;
-    }
-
-    /*!
-    @brief unflatten a previously flattened JSON value
-
-    The function restores the arbitrary nesting of a JSON value that has been
-    flattened before using the @ref flatten() function. The JSON value must
-    meet certain constraints:
-    1. The value must be an object.
-    2. The keys must be JSON pointers (see
-       [RFC 6901](https://tools.ietf.org/html/rfc6901))
-    3. The mapped values must be primitive JSON types.
-
-    @return the original JSON from a flattened version
-
-    @note Empty objects and arrays are flattened by @ref flatten() to `null`
-          values and can not unflattened to their original type. Apart from
-          this example, for a JSON value `j`, the following is always true:
-          `j == j.flatten().unflatten()`.
-
-    @complexity Linear in the size the JSON value.
-
-    @liveexample{The following code shows how a flattened JSON object is
-    unflattened into the original nested JSON object.,unflatten}
-
-    @sa @ref flatten() for the reverse function
-
-    @since version 2.0.0
-    */
-    basic_json unflatten() const
-    {
-        return json_pointer::unflatten(*this);
-    }
-
-    /// @}
-
-    //////////////////////////
-    // JSON Patch functions //
-    //////////////////////////
-
-    /// @name JSON Patch functions
-    /// @{
-
-    /*!
-    @brief applies a JSON patch
-
-    [JSON Patch](http://jsonpatch.com) defines a JSON document structure for
-    expressing a sequence of operations to apply to a JSON) document. With
-    this funcion, a JSON Patch is applied to the current JSON value by
-    executing all operations from the patch.
-
-    @param[in] json_patch  JSON patch document
-    @return patched document
-
-    @note The application of a patch is atomic: Either all operations succeed
-          and the patched document is returned or an exception is thrown. In
-          any case, the original value is not changed: the patch is applied
-          to a copy of the value.
-
-    @throw std::out_of_range if a JSON pointer inside the patch could not
-    be resolved successfully in the current JSON value; example: `"key baz
-    not found"`
-    @throw invalid_argument if the JSON patch is malformed (e.g., mandatory
-    attributes are missing); example: `"operation add must have member path"`
-
-    @complexity Linear in the size of the JSON value and the length of the
-    JSON patch. As usually only a fraction of the JSON value is affected by
-    the patch, the complexity can usually be neglected.
-
-    @liveexample{The following code shows how a JSON patch is applied to a
-    value.,patch}
-
-    @sa @ref diff -- create a JSON patch by comparing two JSON values
-
-    @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
-    @sa [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
-
-    @since version 2.0.0
-    */
-    basic_json patch(const basic_json& json_patch) const
-    {
-        // make a working copy to apply the patch to
-        basic_json result = *this;
-
-        // the valid JSON Patch operations
-        enum class patch_operations {add, remove, replace, move, copy, test, invalid};
-
-        const auto get_op = [](const std::string op)
-        {
-            if (op == "add")
-            {
-                return patch_operations::add;
-            }
-            if (op == "remove")
-            {
-                return patch_operations::remove;
-            }
-            if (op == "replace")
-            {
-                return patch_operations::replace;
-            }
-            if (op == "move")
-            {
-                return patch_operations::move;
-            }
-            if (op == "copy")
-            {
-                return patch_operations::copy;
-            }
-            if (op == "test")
-            {
-                return patch_operations::test;
-            }
-
-            return patch_operations::invalid;
-        };
-
-        // wrapper for "add" operation; add value at ptr
-        const auto operation_add = [&result](json_pointer & ptr, basic_json val)
-        {
-            // adding to the root of the target document means replacing it
-            if (ptr.is_root())
-            {
-                result = val;
-            }
-            else
-            {
-                // make sure the top element of the pointer exists
-                json_pointer top_pointer = ptr.top();
-                if (top_pointer != ptr)
-                {
-                    basic_json& x = result.at(top_pointer);
-                }
-
-                // get reference to parent of JSON pointer ptr
-                const auto last_path = ptr.pop_back();
-                basic_json& parent = result[ptr];
-
-                switch (parent.m_type)
-                {
-                    case value_t::null:
-                    case value_t::object:
-                    {
-                        // use operator[] to add value
-                        parent[last_path] = val;
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        if (last_path == "-")
-                        {
-                            // special case: append to back
-                            parent.push_back(val);
-                        }
-                        else
-                        {
-                            const auto idx = std::stoi(last_path);
-                            if (static_cast<size_type>(idx) > parent.size())
-                            {
-                                // avoid undefined behavior
-                                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
-                            }
-                            else
-                            {
-                                // default case: insert add offset
-                                parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
-                            }
-                        }
-                        break;
-                    }
-
-                    default:
-                    {
-                        // if there exists a parent it cannot be primitive
-                        assert(false);  // LCOV_EXCL_LINE
-                    }
-                }
-            }
-        };
-
-        // wrapper for "remove" operation; remove value at ptr
-        const auto operation_remove = [&result](json_pointer & ptr)
-        {
-            // get reference to parent of JSON pointer ptr
-            const auto last_path = ptr.pop_back();
-            basic_json& parent = result.at(ptr);
-
-            // remove child
-            if (parent.is_object())
-            {
-                // perform range check
-                auto it = parent.find(last_path);
-                if (it != parent.end())
-                {
-                    parent.erase(it);
-                }
-                else
-                {
-                    throw std::out_of_range("key '" + last_path + "' not found");
-                }
-            }
-            else if (parent.is_array())
-            {
-                // note erase performs range check
-                parent.erase(static_cast<size_type>(std::stoi(last_path)));
-            }
-        };
-
-        // type check
-        if (not json_patch.is_array())
-        {
-            // a JSON patch must be an array of objects
-            throw std::invalid_argument("JSON patch must be an array of objects");
-        }
-
-        // iterate and apply th eoperations
-        for (const auto& val : json_patch)
-        {
-            // wrapper to get a value for an operation
-            const auto get_value = [&val](const std::string & op,
-                                          const std::string & member,
-                                          bool string_type) -> basic_json&
-            {
-                // find value
-                auto it = val.m_value.object->find(member);
-
-                // context-sensitive error message
-                const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";
-
-                // check if desired value is present
-                if (it == val.m_value.object->end())
-                {
-                    throw std::invalid_argument(error_msg + " must have member '" + member + "'");
-                }
-
-                // check if result is of type string
-                if (string_type and not it->second.is_string())
-                {
-                    throw std::invalid_argument(error_msg + " must have string member '" + member + "'");
-                }
-
-                // no error: return value
-                return it->second;
-            };
-
-            // type check
-            if (not val.is_object())
-            {
-                throw std::invalid_argument("JSON patch must be an array of objects");
-            }
-
-            // collect mandatory members
-            const std::string op = get_value("op", "op", true);
-            const std::string path = get_value(op, "path", true);
-            json_pointer ptr(path);
-
-            switch (get_op(op))
-            {
-                case patch_operations::add:
-                {
-                    operation_add(ptr, get_value("add", "value", false));
-                    break;
-                }
-
-                case patch_operations::remove:
-                {
-                    operation_remove(ptr);
-                    break;
-                }
-
-                case patch_operations::replace:
-                {
-                    // the "path" location must exist - use at()
-                    result.at(ptr) = get_value("replace", "value", false);
-                    break;
-                }
-
-                case patch_operations::move:
-                {
-                    const std::string from_path = get_value("move", "from", true);
-                    json_pointer from_ptr(from_path);
-
-                    // the "from" location must exist - use at()
-                    basic_json v = result.at(from_ptr);
-
-                    // The move operation is functionally identical to a
-                    // "remove" operation on the "from" location, followed
-                    // immediately by an "add" operation at the target
-                    // location with the value that was just removed.
-                    operation_remove(from_ptr);
-                    operation_add(ptr, v);
-                    break;
-                }
-
-                case patch_operations::copy:
-                {
-                    const std::string from_path = get_value("copy", "from", true);;
-                    const json_pointer from_ptr(from_path);
-
-                    // the "from" location must exist - use at()
-                    result[ptr] = result.at(from_ptr);
-                    break;
-                }
-
-                case patch_operations::test:
-                {
-                    bool success = false;
-                    try
-                    {
-                        // check if "value" matches the one at "path"
-                        // the "path" location must exist - use at()
-                        success = (result.at(ptr) == get_value("test", "value", false));
-                    }
-                    catch (std::out_of_range&)
-                    {
-                        // ignore out of range errors: success remains false
-                    }
-
-                    // throw an exception if test fails
-                    if (not success)
-                    {
-                        throw std::domain_error("unsuccessful: " + val.dump());
-                    }
-
-                    break;
-                }
-
-                case patch_operations::invalid:
-                {
-                    // op must be "add", "remove", "replace", "move", "copy", or
-                    // "test"
-                    throw std::invalid_argument("operation value '" + op + "' is invalid");
-                }
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief creates a diff as a JSON patch
-
-    Creates a [JSON Patch](http://jsonpatch.com) so that value @a source can
-    be changed into the value @a target by calling @ref patch function.
-
-    @invariant For two JSON values @a source and @a target, the following code
-    yields always `true`:
-    @code {.cpp}
-    source.patch(diff(source, target)) == target;
-    @endcode
-
-    @note Currently, only `remove`, `add`, and `replace` operations are
-          generated.
-
-    @param[in] source  JSON value to copare from
-    @param[in] target  JSON value to copare against
-    @param[in] path    helper value to create JSON pointers
-
-    @return a JSON patch to convert the @a source to @a target
-
-    @complexity Linear in the lengths of @a source and @a target.
-
-    @liveexample{The following code shows how a JSON patch is created as a
-    diff for two JSON values.,diff}
-
-    @sa @ref patch -- apply a JSON patch
-
-    @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
-
-    @since version 2.0.0
-    */
-    static basic_json diff(const basic_json& source,
-                           const basic_json& target,
-                           std::string path = "")
-    {
-        // the patch
-        basic_json result(value_t::array);
-
-        // if the values are the same, return empty patch
-        if (source == target)
-        {
-            return result;
-        }
-
-        if (source.type() != target.type())
-        {
-            // different types: replace value
-            result.push_back(
-            {
-                {"op", "replace"},
-                {"path", path},
-                {"value", target}
-            });
-        }
-        else
-        {
-            switch (source.type())
-            {
-                case value_t::array:
-                {
-                    // first pass: traverse common elements
-                    size_t i = 0;
-                    while (i < source.size() and i < target.size())
-                    {
-                        // recursive call to compare array values at index i
-                        auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
-                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
-                        ++i;
-                    }
-
-                    // i now reached the end of at least one array
-                    // in a second pass, traverse the remaining elements
-
-                    // remove my remaining elements
-                    const auto end_index = static_cast<difference_type>(result.size());
-                    while (i < source.size())
-                    {
-                        // add operations in reverse order to avoid invalid
-                        // indices
-                        result.insert(result.begin() + end_index, object(
-                        {
-                            {"op", "remove"},
-                            {"path", path + "/" + std::to_string(i)}
-                        }));
-                        ++i;
-                    }
-
-                    // add other remaining elements
-                    while (i < target.size())
-                    {
-                        result.push_back(
-                        {
-                            {"op", "add"},
-                            {"path", path + "/" + std::to_string(i)},
-                            {"value", target[i]}
-                        });
-                        ++i;
-                    }
-
-                    break;
-                }
-
-                case value_t::object:
-                {
-                    // first pass: traverse this object's elements
-                    for (auto it = source.begin(); it != source.end(); ++it)
-                    {
-                        // escape the key name to be used in a JSON patch
-                        const auto key = json_pointer::escape(it.key());
-
-                        if (target.find(it.key()) != target.end())
-                        {
-                            // recursive call to compare object values at key it
-                            auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key);
-                            result.insert(result.end(), temp_diff.begin(), temp_diff.end());
-                        }
-                        else
-                        {
-                            // found a key that is not in o -> remove it
-                            result.push_back(object(
-                            {
-                                {"op", "remove"},
-                                {"path", path + "/" + key}
-                            }));
-                        }
-                    }
-
-                    // second pass: traverse other object's elements
-                    for (auto it = target.begin(); it != target.end(); ++it)
-                    {
-                        if (source.find(it.key()) == source.end())
-                        {
-                            // found a key that is not in this -> add it
-                            const auto key = json_pointer::escape(it.key());
-                            result.push_back(
-                            {
-                                {"op", "add"},
-                                {"path", path + "/" + key},
-                                {"value", it.value()}
-                            });
-                        }
-                    }
-
-                    break;
-                }
-
-                default:
-                {
-                    // both primitive type: replace value
-                    result.push_back(
-                    {
-                        {"op", "replace"},
-                        {"path", path},
-                        {"value", target}
-                    });
-                    break;
-                }
-            }
-        }
-
-        return result;
-    }
-
-    /// @}
-};
-
-
-/////////////
-// presets //
-/////////////
-
-/*!
-@brief default JSON class
-
-This type is the default specialization of the @ref basic_json class which
-uses the standard template types.
-
-@since version 1.0.0
-*/
-using json = basic_json<>;
-}
-
-
-///////////////////////
-// nonmember support //
-///////////////////////
-
-// specialization of std::swap, and std::hash
-namespace std
-{
-/*!
-@brief exchanges the values of two JSON objects
-
-@since version 1.0.0
-*/
-template <>
-inline void swap(nlohmann::json& j1,
-                 nlohmann::json& j2) noexcept(
-                     is_nothrow_move_constructible<nlohmann::json>::value and
-                     is_nothrow_move_assignable<nlohmann::json>::value
-                 )
-{
-    j1.swap(j2);
-}
-
-/// hash value for JSON objects
-template <>
-struct hash<nlohmann::json>
-{
-    /*!
-    @brief return a hash value for a JSON object
-
-    @since version 1.0.0
-    */
-    std::size_t operator()(const nlohmann::json& j) const
-    {
-        // a naive hashing via the string representation
-        const auto& h = hash<nlohmann::json::string_t>();
-        return h(j.dump());
-    }
-};
-}
-
-/*!
-@brief user-defined string literal for JSON values
-
-This operator implements a user-defined string literal for JSON objects. It
-can be used by adding `"_json"` to a string literal and returns a JSON object
-if no parse error occurred.
-
-@param[in] s  a string representation of a JSON object
-@return a JSON object
-
-@since version 1.0.0
-*/
-inline nlohmann::json operator "" _json(const char* s, std::size_t)
-{
-    return nlohmann::json::parse(reinterpret_cast<const nlohmann::json::string_t::value_type*>(s));
-}
-
-/*!
-@brief user-defined string literal for JSON pointer
-
-This operator implements a user-defined string literal for JSON Pointers. It
-can be used by adding `"_json"` to a string literal and returns a JSON pointer
-object if no parse error occurred.
-
-@param[in] s  a string representation of a JSON Pointer
-@return a JSON pointer object
-
-@since version 2.0.0
-*/
-inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t)
-{
-    return nlohmann::json::json_pointer(s);
-}
-
-// restore GCC/clang diagnostic settings
-#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-    #pragma GCC diagnostic pop
-#endif
-
-#endif
diff --git a/ext/offbase/README.md b/ext/offbase/README.md
new file mode 100644
index 00000000..6668b878
--- /dev/null
+++ b/ext/offbase/README.md
@@ -0,0 +1,59 @@
+A super-minimal in-filesystem persistent JSON object
+======
+
+[We](https://www.zerotier.com/) like minimalism.
+
+Offbase is an extension of the excellent [nlohmann/json](https://github.com/nlohmann/json) C++11 JSON class that adds simple object persistence to/from the filesystem. Objects are stored into a directory hierarchy in fully "expanded" form with each field/value being represented by a separate file.
+
+Features:
+
+ - Very easy to use
+ - Minimal!
+   - Easy to understand and maintain
+	 - Trivial to implement in other languages
+	 - No dependencies beyond standard libraries
+	 - Small code footprint in both source and binary form
+	 - Easy to port to other platforms
+ - Exactly reproduces JSON object hierarchies including all JSON type information
+ - Database can be explored from the shell, browsed in a web browser or file explorer, scanned with `find` and `grep`, etc.
+ - Database can be backed up, restored, versioned, etc. with tools like `git`, `rsync`, `duplicity`, etc.
+ - Alien files like `.git` or `.DS_Store` are harmlessly ignored if present
+ - Saving only changes what's changed to reduce I/O overhead and SSD wear
+
+Limitations and shortcomings:
+
+ - This creates a lot of tiny files, which is inefficient on some filesystems and might run into inode limits in extreme cases. For data sets with more than, say, a million items we recommend a filesystem like `btrfs` or `reiserfs`. Things like [redisfs](https://steve.fi/Software/redisfs/) are also worth exploring. On Linux another alternative is to put the database into `/dev/shm` (RAM disk) and then regularly back it up with `duplicity` or similar.
+ - The whole JSON object is held in memory *twice* for diffing purposes.
+ - Diffing traverses the whole tree and then updates the shadow copy, which makes `commit()` slow for huge data sets. This is not suitable for "big" data where "big" here is probably more than a few hundred megabytes.
+ - Recursion is used, so if you have object hierarchies that are incredibly deep (hundreds or more) it might be possible to overflow your stack and crash your app.
+ - This is not thread safe and must be guarded by a mutex if used in a threaded app.
+
+Caveats:
+
+ - Key names are escaped for safety in the filesystem, but we still don't recommend allowing external users to set just anything into your JSON store. See the point about recursion under limitations.
+
+Future:
+
+ - It would not be too hard to tie this into a filesystem change monitoring API and automatically read changes from disk if they are detected. This would allow the database to be edited "live" in the filesystem.
+   - In theory this could provide replication or clustering through distributed filesystems, file syncing, or things like [Amazon Elastic Filesystem](https://aws.amazon.com/efs/).
+ - Recursion could be factored out to get rid of any object hierarchy depth constraints.
+ - Mutexes could be integrated somehow to allow for finer grained locking in multithreaded apps.
+ - Diffing and selective updates could be made more memory and CPU efficient using hashes, etc.
+
+## How to Use
+
+The `offbase` class just extends [nlohmann::json](https://github.com/nlohmann/json) and gives you a JSON object. Take care to make sure you don't change the type of the 'root' object represented by the 'offbase' instance from JSON 'object'. Anything under it can of course be any JSON type, including any object.
+
+Just put data into the object and then periodically call `commit()` to persist changes to disk. The `commit()` method diffs the current contents of the object with what it knows to have been previously persisted to disk and modifies the representation on disk to match. This can be done after writes or periodically in a background thread.
+
+See comments in `offbase.hpp` for full documentation including details about error handling, etc.
+
+## Persistence format
+
+The base object represented by the `offbase` instance is persisted into a directory hierarchy under its base path. Files and directories are named according to a simple convention of `keyname.typecode` where `keyname` is an escaped key name (or hex array index in the case of arrays) and `typecode` is a single character indicating whether the item is a JSON value, array, or object.
+
+ - `*.V`: JSON values (actual value type is inferred during JSON parse)
+ - `*.O`: JSON objects (these are subdirectories)
+ - `*.A`: JSON arrays (also subdirectories containing items by hex array index)
+
+There are in theory simpler ways to represent JSON in a filesystem, such as the "flattened" JSON "pointer" format, but this has the disadvantage of not disambiguating objects vs. arrays. Offbase's persistence format is designed to perfectly reproduce the exact same JSON tree on load as was most recently committed.
diff --git a/ext/offbase/json/LICENSE.MIT b/ext/offbase/json/LICENSE.MIT
new file mode 100644
index 00000000..e2ac4891
--- /dev/null
+++ b/ext/offbase/json/LICENSE.MIT
@@ -0,0 +1,22 @@
+The library is licensed under the MIT License 
+<http://opensource.org/licenses/MIT>:
+
+Copyright (c) 2013-2016 Niels Lohmann
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/ext/offbase/json/README.md b/ext/offbase/json/README.md
new file mode 100644
index 00000000..c0bb61b1
--- /dev/null
+++ b/ext/offbase/json/README.md
@@ -0,0 +1,511 @@
+[![JSON for Modern C++](https://raw.githubusercontent.com/nlohmann/json/master/doc/json.gif)](https://github.com/nlohmann/json/releases)
+
+[![Build Status](https://travis-ci.org/nlohmann/json.svg?branch=master)](https://travis-ci.org/nlohmann/json)
+[![Build Status](https://ci.appveyor.com/api/projects/status/1acb366xfyg3qybk?svg=true)](https://ci.appveyor.com/project/nlohmann/json)
+[![Coverage Status](https://img.shields.io/coveralls/nlohmann/json.svg)](https://coveralls.io/r/nlohmann/json)
+[![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
+[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/p5o4znPnGHJpDVqN)
+[![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](http://nlohmann.github.io/json)
+[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
+[![Github Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
+[![Github Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](http://github.com/nlohmann/json/issues)
+
+## Design goals
+
+There are myriads of [JSON](http://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
+
+- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you know, what I mean.
+
+- **Trivial integration**. Our whole code consists of a single header file [`json.hpp`](https://github.com/nlohmann/json/blob/develop/src/json.hpp). That's it. No library, no subproject, no dependencies, no complex build system. The class is written in vanilla C++11. All in all, everything should require no adjustment of your compiler flags or project settings.
+
+- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/blob/master/test/src/unit.cpp) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) that there are no memory leaks.
+
+Other aspects were not so important to us:
+
+- **Memory efficiency**. Each JSON object has an overhead of one pointer (the maximal size of a union) and one enumeration element (1 byte). The default generalization uses the following C++ data types: `std::string` for strings, `int64_t`, `uint64_t` or `double` for numbers, `std::map` for objects, `std::vector` for arrays, and `bool` for Booleans. However, you can template the generalized class `basic_json` to your needs.
+
+- **Speed**. We currently implement the parser as naive [recursive descent parser](http://en.wikipedia.org/wiki/Recursive_descent_parser) with hand coded string handling. It is fast enough, but a [LALR-parser](http://en.wikipedia.org/wiki/LALR_parser) may be even faster (but would consist of more files which makes the integration harder).
+
+See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.github/CONTRIBUTING.md#please-dont) for more information.
+
+
+## Integration
+
+The single required source, file `json.hpp` is in the `src` directory or [released here](https://github.com/nlohmann/json/releases). All you need to do is add
+
+```cpp
+#include "json.hpp"
+
+// for convenience
+using json = nlohmann::json;
+```
+
+to the files you want to use JSON objects. That's it. Do not forget to set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).
+
+:beer: If you are using OS X and [Homebrew](http://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann_json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann_json --HEAD`.
+
+
+## Examples
+
+Here are some examples to give you an idea how to use the class.
+
+Assume you want to create the JSON object
+
+```json
+{
+  "pi": 3.141,
+  "happy": true,
+  "name": "Niels",
+  "nothing": null,
+  "answer": {
+    "everything": 42
+  },
+  "list": [1, 0, 2],
+  "object": {
+    "currency": "USD",
+    "value": 42.99
+  }
+}
+```
+
+With the JSON class, you could write:
+
+```cpp
+// create an empty structure (null)
+json j;
+
+// add a number that is stored as double (note the implicit conversion of j to an object)
+j["pi"] = 3.141;
+
+// add a Boolean that is stored as bool
+j["happy"] = true;
+
+// add a string that is stored as std::string
+j["name"] = "Niels";
+
+// add another null object by passing nullptr
+j["nothing"] = nullptr;
+
+// add an object inside the object
+j["answer"]["everything"] = 42;
+
+// add an array that is stored as std::vector (using an initializer list)
+j["list"] = { 1, 0, 2 };
+
+// add another object (using an initializer list of pairs)
+j["object"] = { {"currency", "USD"}, {"value", 42.99} };
+
+// instead, you could also write (which looks very similar to the JSON above)
+json j2 = {
+  {"pi", 3.141},
+  {"happy", true},
+  {"name", "Niels"},
+  {"nothing", nullptr},
+  {"answer", {
+    {"everything", 42}
+  }},
+  {"list", {1, 0, 2}},
+  {"object", {
+    {"currency", "USD"},
+    {"value", 42.99}
+  }}
+};
+```
+
+Note that in all these cases, you never need to "tell" the compiler which JSON value you want to use. If you want to be explicit or express some edge cases, the functions `json::array` and `json::object` will help:
+
+```cpp
+// a way to express the empty array []
+json empty_array_explicit = json::array();
+
+// ways to express the empty object {}
+json empty_object_implicit = json({});
+json empty_object_explicit = json::object();
+
+// a way to express an _array_ of key/value pairs [["currency", "USD"], ["value", 42.99]]
+json array_not_object = { json::array({"currency", "USD"}), json::array({"value", 42.99}) };
+```
+
+
+### Serialization / Deserialization
+
+You can create an object (deserialization) by appending `_json` to a string literal:
+
+```cpp
+// create object from string literal
+json j = "{ \"happy\": true, \"pi\": 3.141 }"_json;
+
+// or even nicer with a raw string literal
+auto j2 = R"(
+  {
+    "happy": true,
+    "pi": 3.141
+  }
+)"_json;
+
+// or explicitly
+auto j3 = json::parse("{ \"happy\": true, \"pi\": 3.141 }");
+```
+
+You can also get a string representation (serialize):
+
+```cpp
+// explicit conversion to string
+std::string s = j.dump();    // {\"happy\":true,\"pi\":3.141}
+
+// serialization with pretty printing
+// pass in the amount of spaces to indent
+std::cout << j.dump(4) << std::endl;
+// {
+//     "happy": true,
+//     "pi": 3.141
+// }
+```
+
+You can also use streams to serialize and deserialize:
+
+```cpp
+// deserialize from standard input
+json j;
+std::cin >> j;
+
+// serialize to standard output
+std::cout << j;
+
+// the setw manipulator was overloaded to set the indentation for pretty printing
+std::cout << std::setw(4) << j << std::endl;
+```
+
+These operators work for any subclasses of `std::istream` or `std::ostream`.
+
+Please note that setting the exception bit for `failbit` is inappropriate for this use case. It will result in program termination due to the `noexcept` specifier in use.
+
+
+### STL-like access
+
+We designed the JSON class to behave just like an STL container. In fact, it satisfies the [**ReversibleContainer**](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) requirement.
+
+```cpp
+// create an array using push_back
+json j;
+j.push_back("foo");
+j.push_back(1);
+j.push_back(true);
+
+// iterate the array
+for (json::iterator it = j.begin(); it != j.end(); ++it) {
+  std::cout << *it << '\n';
+}
+
+// range-based for
+for (auto& element : j) {
+  std::cout << element << '\n';
+}
+
+// getter/setter
+const std::string tmp = j[0];
+j[1] = 42;
+bool foo = j.at(2);
+
+// other stuff
+j.size();     // 3 entries
+j.empty();    // false
+j.type();     // json::value_t::array
+j.clear();    // the array is empty again
+
+// convenience type checkers
+j.is_null();
+j.is_boolean();
+j.is_number();
+j.is_object();
+j.is_array();
+j.is_string();
+
+// comparison
+j == "[\"foo\", 1, true]"_json;  // true
+
+// create an object
+json o;
+o["foo"] = 23;
+o["bar"] = false;
+o["baz"] = 3.141;
+
+// special iterator member functions for objects
+for (json::iterator it = o.begin(); it != o.end(); ++it) {
+  std::cout << it.key() << " : " << it.value() << "\n";
+}
+
+// find an entry
+if (o.find("foo") != o.end()) {
+  // there is an entry with key "foo"
+}
+
+// or simpler using count()
+int foo_present = o.count("foo"); // 1
+int fob_present = o.count("fob"); // 0
+
+// delete an entry
+o.erase("foo");
+```
+
+
+### Conversion from STL containers
+
+Any sequence container (`std::array`, `std::vector`, `std::deque`, `std::forward_list`, `std::list`) whose values can be used to construct JSON types (e.g., integers, floating point numbers, Booleans, string types, or again STL containers described in this section) can be used to create a JSON array. The same holds for similar associative containers (`std::set`, `std::multiset`, `std::unordered_set`, `std::unordered_multiset`), but in these cases the order of the elements of the array depends how the elements are ordered in the respective STL container.
+
+```cpp
+std::vector<int> c_vector {1, 2, 3, 4};
+json j_vec(c_vector);
+// [1, 2, 3, 4]
+
+std::deque<double> c_deque {1.2, 2.3, 3.4, 5.6};
+json j_deque(c_deque);
+// [1.2, 2.3, 3.4, 5.6]
+
+std::list<bool> c_list {true, true, false, true};
+json j_list(c_list);
+// [true, true, false, true]
+
+std::forward_list<int64_t> c_flist {12345678909876, 23456789098765, 34567890987654, 45678909876543};
+json j_flist(c_flist);
+// [12345678909876, 23456789098765, 34567890987654, 45678909876543]
+
+std::array<unsigned long, 4> c_array {{1, 2, 3, 4}};
+json j_array(c_array);
+// [1, 2, 3, 4]
+
+std::set<std::string> c_set {"one", "two", "three", "four", "one"};
+json j_set(c_set); // only one entry for "one" is used
+// ["four", "one", "three", "two"]
+
+std::unordered_set<std::string> c_uset {"one", "two", "three", "four", "one"};
+json j_uset(c_uset); // only one entry for "one" is used
+// maybe ["two", "three", "four", "one"]
+
+std::multiset<std::string> c_mset {"one", "two", "one", "four"};
+json j_mset(c_mset); // only one entry for "one" is used
+// maybe ["one", "two", "four"]
+
+std::unordered_multiset<std::string> c_umset {"one", "two", "one", "four"};
+json j_umset(c_umset); // both entries for "one" are used
+// maybe ["one", "two", "one", "four"]
+```
+
+Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON types (see examples above) can be used to to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
+
+```cpp
+std::map<std::string, int> c_map { {"one", 1}, {"two", 2}, {"three", 3} };
+json j_map(c_map);
+// {"one": 1, "three": 3, "two": 2 }
+
+std::unordered_map<const char*, double> c_umap { {"one", 1.2}, {"two", 2.3}, {"three", 3.4} };
+json j_umap(c_umap);
+// {"one": 1.2, "two": 2.3, "three": 3.4}
+
+std::multimap<std::string, bool> c_mmap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
+json j_mmap(c_mmap); // only one entry for key "three" is used
+// maybe {"one": true, "two": true, "three": true}
+
+std::unordered_multimap<std::string, bool> c_ummap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
+json j_ummap(c_ummap); // only one entry for key "three" is used
+// maybe {"one": true, "two": true, "three": true}
+```
+
+### JSON Pointer and JSON Patch
+
+The library supports **JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) as alternative means to address structured values. On top of this, **JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) allows to describe differences between two JSON values - effectively allowing patch and diff operations known from Unix.
+
+```cpp
+// a JSON value
+json j_original = R"({
+  "baz": ["one", "two", "three"],
+  "foo": "bar"
+})"_json;
+
+// access members with a JSON pointer (RFC 6901)
+j_original["/baz/1"_json_pointer];
+// "two"
+
+// a JSON patch (RFC 6902)
+json j_patch = R"([
+  { "op": "replace", "path": "/baz", "value": "boo" },
+  { "op": "add", "path": "/hello", "value": ["world"] },
+  { "op": "remove", "path": "/foo"}
+])"_json;
+
+// apply the patch
+json j_result = j_original.patch(j_patch);
+// {
+//    "baz": "boo",
+//    "hello": ["world"]
+// }
+
+// calculate a JSON patch from two JSON values
+json::diff(j_result, j_original);
+// [
+//   { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] },
+//   { "op": "remove","path": "/hello" },
+//   { "op": "add", "path": "/foo", "value": "bar" }
+// ]
+```
+
+
+### Implicit conversions
+
+The type of the JSON object is determined automatically by the expression to store. Likewise, the stored value is implicitly converted.
+
+```cpp
+// strings
+std::string s1 = "Hello, world!";
+json js = s1;
+std::string s2 = js;
+
+// Booleans
+bool b1 = true;
+json jb = b1;
+bool b2 = jb;
+
+// numbers
+int i = 42;
+json jn = i;
+double f = jn;
+
+// etc.
+```
+
+You can also explicitly ask for the value:
+
+```cpp
+std::string vs = js.get<std::string>();
+bool vb = jb.get<bool>();
+int vi = jn.get<int>();
+
+// etc.
+```
+
+
+## Supported compilers
+
+Though it's 2016 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
+
+- GCC 4.9 - 6.0 (and possibly later)
+- Clang 3.4 - 3.9 (and possibly later)
+- Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
+
+I would be happy to learn about other compilers/versions.
+
+Please note:
+
+- GCC 4.8 does not work because of two bugs ([55817](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55817) and [57824](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57824)) in the C++11 support. Note there is a [pull request](https://github.com/nlohmann/json/pull/212) to fix some of the issues.
+- Android defaults to using very old compilers and C++ libraries. To fix this, add the following to your `Application.mk`. This will switch to the LLVM C++ library, the Clang compiler, and enable C++11 and other features disabled by default.
+ 
+    ```
+    APP_STL := c++_shared
+    NDK_TOOLCHAIN_VERSION := clang3.6
+    APP_CPPFLAGS += -frtti -fexceptions
+    ```
+ 
+    The code compiles successfully with [Android NDK](https://developer.android.com/ndk/index.html?hl=ml), Revision 9 - 11 (and possibly later) and [CrystaX's Android NDK](https://www.crystax.net/en/android/ndk) version 10.
+
+- For GCC running on MinGW or Android SDK, the error `'to_string' is not a member of 'std'` (or similarly, for `strtod`) may occur. Note this is not an issue with the code,  but rather with the compiler itself. On Android, see above to build with a newer environment.  For MinGW, please refer to [this site](http://tehsausage.com/mingw-to-string) and [this discussion](https://github.com/nlohmann/json/issues/136) for information on how to fix this bug. For Android NDK using `APP_STL := gnustl_static`, please refer to [this discussion](https://github.com/nlohmann/json/issues/219).
+
+The following compilers are currently used in continuous integration at [Travis](https://travis-ci.org/nlohmann/json) and [AppVeyor](https://ci.appveyor.com/project/nlohmann/json):
+
+| Compiler        | Operating System             | Version String |
+|-----------------|------------------------------|----------------|
+| GCC 4.9.3       | Ubuntu 14.04.4 LTS           | g++-4.9 (Ubuntu 4.9.3-8ubuntu2~14.04) 4.9.3 |
+| GCC 5.3.0       | Ubuntu 14.04.4 LTS           | g++-5 (Ubuntu 5.3.0-3ubuntu1~14.04) 5.3.0 20151204 |
+| GCC 6.1.1       | Ubuntu 14.04.4 LTS           | g++-6 (Ubuntu 6.1.1-3ubuntu11~14.04.1) 6.1.1 20160511 |
+| Clang 3.8.0     | Ubuntu 14.04.4 LTS           | clang version 3.8.0 (tags/RELEASE_380/final) |
+| Clang Xcode 6.1 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) |
+| Clang Xcode 6.2 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) |
+| Clang Xcode 6.3 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn) |
+| Clang Xcode 6.4 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn) |
+| Clang Xcode 7.1 | Darwin Kernel Version 14.5.0 (OSX 10.10.5) | Apple LLVM version 7.0.0 (clang-700.1.76) |
+| Clang Xcode 7.2 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.0.2 (clang-700.1.81) |
+| Clang Xcode 7.3 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.3.0 (clang-703.0.29) |
+| Clang Xcode 8.0 | Darwin Kernel Version 15.5.0 (OSX 10.11.5) | Apple LLVM version 8.0.0 (clang-800.0.24.1) |
+| Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25123.0 | 
+
+
+## License
+
+<img align="right" src="http://opensource.org/trademarks/opensource/OSI-Approved-License-100x137.png">
+
+The class is licensed under the [MIT License](http://opensource.org/licenses/MIT):
+
+Copyright &copy; 2013-2016 [Niels Lohmann](http://nlohmann.me)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+## Thanks
+
+I deeply appreciate the help of the following people.
+
+- [Teemperor](https://github.com/Teemperor) implemented CMake support and lcov integration, realized escape and Unicode handling in the string parser, and fixed the JSON serialization.
+- [elliotgoodrich](https://github.com/elliotgoodrich) fixed an issue with double deletion in the iterator classes.
+- [kirkshoop](https://github.com/kirkshoop) made the iterators of the class composable to other libraries.
+- [wancw](https://github.com/wanwc) fixed a bug that hindered the class to compile with Clang.
+- Tomas Åblad found a bug in the iterator implementation.
+- [Joshua C. Randall](https://github.com/jrandall) fixed a bug in the floating-point serialization.
+- [Aaron Burghardt](https://github.com/aburgh) implemented code to parse streams incrementally. Furthermore, he greatly improved the parser class by allowing the definition of a filter function to discard undesired elements while parsing.
+- [Daniel Kopeček](https://github.com/dkopecek) fixed a bug in the compilation with GCC 5.0.
+- [Florian Weber](https://github.com/Florianjw) fixed a bug in and improved the performance of the comparison operators.
+- [Eric Cornelius](https://github.com/EricMCornelius) pointed out a bug in the handling with NaN and infinity values. He also improved the performance of the string escaping.
+- [易思龙](https://github.com/likebeta) implemented a conversion from anonymous enums.
+- [kepkin](https://github.com/kepkin) patiently pushed forward the support for Microsoft Visual studio.
+- [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators and helped with numerous hints and improvements.
+- [Caio Luppi](https://github.com/caiovlp) fixed a bug in the Unicode handling.
+- [dariomt](https://github.com/dariomt) fixed some typos in the examples.
+- [Daniel Frey](https://github.com/d-frey) cleaned up some pointers and implemented exception-safe memory allocation.
+- [Colin Hirsch](https://github.com/ColinH) took care of a small namespace issue.
+- [Huu Nguyen](https://github.com/whoshuu) correct a variable name in the documentation.
+- [Silverweed](https://github.com/silverweed) overloaded `parse()` to accept an rvalue reference.
+- [dariomt](https://github.com/dariomt) fixed a subtlety in MSVC type support and implemented the `get_ref()` function to get a reference to stored values.
+- [ZahlGraf](https://github.com/ZahlGraf) added a workaround that allows compilation using Android NDK.
+- [whackashoe](https://github.com/whackashoe) replaced a function that was marked as unsafe by Visual Studio.
+- [406345](https://github.com/406345) fixed two small warnings.
+- [Glen Fernandes](https://github.com/glenfe) noted a potential portability problem in the `has_mapped_type` function.
+- [Corbin Hughes](https://github.com/nibroc) fixed some typos in the contribution guidelines.
+- [twelsby](https://github.com/twelsby) fixed the array subscript operator, an issue that failed the MSVC build, and floating-point parsing/dumping. He further added support for unsigned integer numbers and implemented better roundtrip support for parsed numbers.
+- [Volker Diels-Grabsch](https://github.com/vog) fixed a link in the README file.
+- [msm-](https://github.com/msm-) added support for american fuzzy lop. 
+- [Annihil](https://github.com/Annihil) fixed an example in the README file.
+- [Themercee](https://github.com/Themercee) noted a wrong URL in the README file.
+- [Lv Zheng](https://github.com/lv-zheng) fixed a namespace issue with `int64_t` and `uint64_t`.
+- [abc100m](https://github.com/abc100m) analyzed the issues with GCC 4.8 and proposed a [partial solution](https://github.com/nlohmann/json/pull/212).
+- [zewt](https://github.com/zewt) added useful notes to the README file about Android.
+- [Róbert Márki](https://github.com/robertmrk) added a fix to use move iterators and improved the integration via CMake.
+- [Chris Kitching](https://github.com/ChrisKitching) cleaned up the CMake files.
+- [Tom Needham](https://github.com/06needhamt) fixed a subtle bug with MSVC 2015 which was also proposed by [Michael K.](https://github.com/Epidal).
+- [Mário Feroldi](https://github.com/thelostt) fixed a small typo.
+- [duncanwerner](https://github.com/duncanwerner) found a really embarrassing performance regression in the 2.0.0 release.
+- [Damien](https://github.com/dtoma) fixed one of the last conversion warnings.
+
+Thanks a lot for helping out!
+
+
+## Notes
+
+- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](http://en.cppreference.com/w/cpp/error/assert).
+- As the exact type of a number is not defined in the [JSON specification](http://rfc7159.net/rfc7159), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
+
+
+## Execute unit tests
+
+To compile and run the tests, you need to execute
+
+```sh
+$ make
+$ ./json_unit "*"
+
+===============================================================================
+All tests passed (8905012 assertions in 32 test cases)
+```
+
+For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).
diff --git a/ext/offbase/json/json.hpp b/ext/offbase/json/json.hpp
new file mode 100644
index 00000000..878fb899
--- /dev/null
+++ b/ext/offbase/json/json.hpp
@@ -0,0 +1,10435 @@
+/*
+    __ _____ _____ _____
+ __|  |   __|     |   | |  JSON for Modern C++
+|  |  |__   |  |  | | | |  version 2.0.2
+|_____|_____|_____|_|___|  https://github.com/nlohmann/json
+
+Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+Copyright (c) 2013-2016 Niels Lohmann <http://nlohmann.me>.
+
+Permission is hereby  granted, free of charge, to any  person obtaining a copy
+of this software and associated  documentation files (the "Software"), to deal
+in the Software  without restriction, including without  limitation the rights
+to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
+copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
+IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
+FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
+AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
+LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#ifndef NLOHMANN_JSON_HPP
+#define NLOHMANN_JSON_HPP
+
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <ciso646>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <functional>
+#include <initializer_list>
+#include <iomanip>
+#include <iostream>
+#include <iterator>
+#include <limits>
+#include <locale>
+#include <map>
+#include <memory>
+#include <numeric>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+// exclude unsupported compilers
+#if defined(__clang__)
+    #define CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
+    #if CLANG_VERSION < 30400
+        #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
+    #endif
+#elif defined(__GNUC__)
+    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
+    #if GCC_VERSION < 40900
+        #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
+    #endif
+#endif
+
+// disable float-equal warnings on GCC/clang
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+
+/*!
+@brief namespace for Niels Lohmann
+@see https://github.com/nlohmann
+@since version 1.0.0
+*/
+namespace nlohmann
+{
+
+
+/*!
+@brief unnamed namespace with internal helper functions
+@since version 1.0.0
+*/
+namespace
+{
+/*!
+@brief Helper to determine whether there's a key_type for T.
+
+Thus helper is used to tell associative containers apart from other containers
+such as sequence containers. For instance, `std::map` passes the test as it
+contains a `mapped_type`, whereas `std::vector` fails the test.
+
+@sa http://stackoverflow.com/a/7728728/266378
+@since version 1.0.0
+*/
+template<typename T>
+struct has_mapped_type
+{
+  private:
+    template<typename C> static char test(typename C::mapped_type*);
+    template<typename C> static char (&test(...))[2];
+  public:
+    static constexpr bool value = sizeof(test<T>(0)) == 1;
+};
+
+/*!
+@brief helper class to create locales with decimal point
+
+This struct is used a default locale during the JSON serialization. JSON
+requires the decimal point to be `.`, so this function overloads the
+`do_decimal_point()` function to return `.`. This function is called by
+float-to-string conversions to retrieve the decimal separator between integer
+and fractional parts.
+
+@sa https://github.com/nlohmann/json/issues/51#issuecomment-86869315
+@since version 2.0.0
+*/
+struct DecimalSeparator : std::numpunct<char>
+{
+    char do_decimal_point() const
+    {
+        return '.';
+    }
+};
+
+}
+
+/*!
+@brief a class to store JSON values
+
+@tparam ObjectType type for JSON objects (`std::map` by default; will be used
+in @ref object_t)
+@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
+in @ref array_t)
+@tparam StringType type for JSON strings and object keys (`std::string` by
+default; will be used in @ref string_t)
+@tparam BooleanType type for JSON booleans (`bool` by default; will be used
+in @ref boolean_t)
+@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
+default; will be used in @ref number_integer_t)
+@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
+`uint64_t` by default; will be used in @ref number_unsigned_t)
+@tparam NumberFloatType type for JSON floating-point numbers (`double` by
+default; will be used in @ref number_float_t)
+@tparam AllocatorType type of the allocator to use (`std::allocator` by
+default)
+
+@requirement The class satisfies the following concept requirements:
+- Basic
+ - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
+   JSON values can be default constructed. The result will be a JSON null value.
+ - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
+   A JSON value can be constructed from an rvalue argument.
+ - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
+   A JSON value can be copy-constructed from an lvalue expression.
+ - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
+   A JSON value van be assigned from an rvalue argument.
+ - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
+   A JSON value can be copy-assigned from an lvalue expression.
+ - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
+   JSON values can be destructed.
+- Layout
+ - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
+   JSON values have
+   [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
+   All non-static data members are private and standard layout types, the class
+   has no virtual functions or (virtual) base classes.
+- Library-wide
+ - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
+   JSON values can be compared with `==`, see @ref
+   operator==(const_reference,const_reference).
+ - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
+   JSON values can be compared with `<`, see @ref
+   operator<(const_reference,const_reference).
+ - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
+   Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
+   other compatible types, using unqualified function call @ref swap().
+ - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
+   JSON values can be compared against `std::nullptr_t` objects which are used
+   to model the `null` value.
+- Container
+ - [Container](http://en.cppreference.com/w/cpp/concept/Container):
+   JSON values can be used like STL containers and provide iterator access.
+ - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
+   JSON values can be used like STL containers and provide reverse iterator
+   access.
+
+@invariant The member variables @a m_value and @a m_type have the following
+relationship:
+- If `m_type == value_t::object`, then `m_value.object != nullptr`.
+- If `m_type == value_t::array`, then `m_value.array != nullptr`.
+- If `m_type == value_t::string`, then `m_value.string != nullptr`.
+The invariants are checked by member function assert_invariant().
+
+@internal
+@note ObjectType trick from http://stackoverflow.com/a/9860911
+@endinternal
+
+@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
+Format](http://rfc7159.net/rfc7159)
+
+@since version 1.0.0
+
+@nosubgrouping
+*/
+template <
+    template<typename U, typename V, typename... Args> class ObjectType = std::map,
+    template<typename U, typename... Args> class ArrayType = std::vector,
+    class StringType = std::string,
+    class BooleanType = bool,
+    class NumberIntegerType = std::int64_t,
+    class NumberUnsignedType = std::uint64_t,
+    class NumberFloatType = double,
+    template<typename U> class AllocatorType = std::allocator
+    >
+class basic_json
+{
+  private:
+    /// workaround type for MSVC
+    using basic_json_t = basic_json<ObjectType, ArrayType, StringType,
+          BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType,
+          AllocatorType>;
+
+  public:
+    // forward declarations
+    template<typename Base> class json_reverse_iterator;
+    class json_pointer;
+
+    /////////////////////
+    // container types //
+    /////////////////////
+
+    /// @name container types
+    /// The canonic container types to use @ref basic_json like any other STL
+    /// container.
+    /// @{
+
+    /// the type of elements in a basic_json container
+    using value_type = basic_json;
+
+    /// the type of an element reference
+    using reference = value_type&;
+    /// the type of an element const reference
+    using const_reference = const value_type&;
+
+    /// a type to represent differences between iterators
+    using difference_type = std::ptrdiff_t;
+    /// a type to represent container sizes
+    using size_type = std::size_t;
+
+    /// the allocator type
+    using allocator_type = AllocatorType<basic_json>;
+
+    /// the type of an element pointer
+    using pointer = typename std::allocator_traits<allocator_type>::pointer;
+    /// the type of an element const pointer
+    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
+
+    /// an iterator for a basic_json container
+    class iterator;
+    /// a const iterator for a basic_json container
+    class const_iterator;
+    /// a reverse iterator for a basic_json container
+    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
+    /// a const reverse iterator for a basic_json container
+    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;
+
+    /// @}
+
+
+    /*!
+    @brief returns the allocator associated with the container
+    */
+    static allocator_type get_allocator()
+    {
+        return allocator_type();
+    }
+
+
+    ///////////////////////////
+    // JSON value data types //
+    ///////////////////////////
+
+    /// @name JSON value data types
+    /// The data types to store a JSON value. These types are derived from
+    /// the template arguments passed to class @ref basic_json.
+    /// @{
+
+    /*!
+    @brief a type for an object
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
+    > An object is an unordered collection of zero or more name/value pairs,
+    > where a name is a string and a value is a string, number, boolean, null,
+    > object, or array.
+
+    To store objects in C++, a type is defined by the template parameters
+    described below.
+
+    @tparam ObjectType  the container to store objects (e.g., `std::map` or
+    `std::unordered_map`)
+    @tparam StringType the type of the keys or names (e.g., `std::string`).
+    The comparison function `std::less<StringType>` is used to order elements
+    inside the container.
+    @tparam AllocatorType the allocator to use for objects (e.g.,
+    `std::allocator`)
+
+    #### Default type
+
+    With the default values for @a ObjectType (`std::map`), @a StringType
+    (`std::string`), and @a AllocatorType (`std::allocator`), the default
+    value for @a object_t is:
+
+    @code {.cpp}
+    std::map<
+      std::string, // key_type
+      basic_json, // value_type
+      std::less<std::string>, // key_compare
+      std::allocator<std::pair<const std::string, basic_json>> // allocator_type
+    >
+    @endcode
+
+    #### Behavior
+
+    The choice of @a object_t influences the behavior of the JSON class. With
+    the default type, objects have the following behavior:
+
+    - When all names are unique, objects will be interoperable in the sense
+      that all software implementations receiving that object will agree on
+      the name-value mappings.
+    - When the names within an object are not unique, later stored name/value
+      pairs overwrite previously stored name/value pairs, leaving the used
+      names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will
+      be treated as equal and both stored as `{"key": 1}`.
+    - Internally, name/value pairs are stored in lexicographical order of the
+      names. Objects will also be serialized (see @ref dump) in this order.
+      For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored
+      and serialized as `{"a": 2, "b": 1}`.
+    - When comparing objects, the order of the name/value pairs is irrelevant.
+      This makes objects interoperable in the sense that they will not be
+      affected by these differences. For instance, `{"b": 1, "a": 2}` and
+      `{"a": 2, "b": 1}` will be treated as equal.
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the maximum depth of nesting.
+
+    In this class, the object's limit of nesting is not constraint explicitly.
+    However, a maximum depth of nesting may be introduced by the compiler or
+    runtime environment. A theoretical limit can be queried by calling the
+    @ref max_size function of a JSON object.
+
+    #### Storage
+
+    Objects are stored as pointers in a @ref basic_json type. That is, for any
+    access to object values, a pointer of type `object_t*` must be
+    dereferenced.
+
+    @sa @ref array_t -- type for an array value
+
+    @since version 1.0.0
+
+    @note The order name/value pairs are added to the object is *not*
+    preserved by the library. Therefore, iterating an object may return
+    name/value pairs in a different order than they were originally stored. In
+    fact, keys will be traversed in alphabetical order as `std::map` with
+    `std::less` is used by default. Please note this behavior conforms to [RFC
+    7159](http://rfc7159.net/rfc7159), because any order implements the
+    specified "unordered" nature of JSON objects.
+    */
+    using object_t = ObjectType<StringType,
+          basic_json,
+          std::less<StringType>,
+          AllocatorType<std::pair<const StringType,
+          basic_json>>>;
+
+    /*!
+    @brief a type for an array
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
+    > An array is an ordered sequence of zero or more values.
+
+    To store objects in C++, a type is defined by the template parameters
+    explained below.
+
+    @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
+    `std::list`)
+    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
+
+    #### Default type
+
+    With the default values for @a ArrayType (`std::vector`) and @a
+    AllocatorType (`std::allocator`), the default value for @a array_t is:
+
+    @code {.cpp}
+    std::vector<
+      basic_json, // value_type
+      std::allocator<basic_json> // allocator_type
+    >
+    @endcode
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the maximum depth of nesting.
+
+    In this class, the array's limit of nesting is not constraint explicitly.
+    However, a maximum depth of nesting may be introduced by the compiler or
+    runtime environment. A theoretical limit can be queried by calling the
+    @ref max_size function of a JSON array.
+
+    #### Storage
+
+    Arrays are stored as pointers in a @ref basic_json type. That is, for any
+    access to array values, a pointer of type `array_t*` must be dereferenced.
+
+    @sa @ref object_t -- type for an object value
+
+    @since version 1.0.0
+    */
+    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
+
+    /*!
+    @brief a type for a string
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
+    > A string is a sequence of zero or more Unicode characters.
+
+    To store objects in C++, a type is defined by the template parameter
+    described below. Unicode values are split by the JSON class into
+    byte-sized characters during deserialization.
+
+    @tparam StringType  the container to store strings (e.g., `std::string`).
+    Note this container is used for keys/names in objects, see @ref object_t.
+
+    #### Default type
+
+    With the default values for @a StringType (`std::string`), the default
+    value for @a string_t is:
+
+    @code {.cpp}
+    std::string
+    @endcode
+
+    #### String comparison
+
+    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    > Software implementations are typically required to test names of object
+    > members for equality. Implementations that transform the textual
+    > representation into sequences of Unicode code units and then perform the
+    > comparison numerically, code unit by code unit, are interoperable in the
+    > sense that implementations will agree in all cases on equality or
+    > inequality of two strings. For example, implementations that compare
+    > strings with escaped characters unconverted may incorrectly find that
+    > `"a\\b"` and `"a\u005Cb"` are not equal.
+
+    This implementation is interoperable as it does compare strings code unit
+    by code unit.
+
+    #### Storage
+
+    String values are stored as pointers in a @ref basic_json type. That is,
+    for any access to string values, a pointer of type `string_t*` must be
+    dereferenced.
+
+    @since version 1.0.0
+    */
+    using string_t = StringType;
+
+    /*!
+    @brief a type for a boolean
+
+    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
+    type which differentiates the two literals `true` and `false`.
+
+    To store objects in C++, a type is defined by the template parameter @a
+    BooleanType which chooses the type to use.
+
+    #### Default type
+
+    With the default values for @a BooleanType (`bool`), the default value for
+    @a boolean_t is:
+
+    @code {.cpp}
+    bool
+    @endcode
+
+    #### Storage
+
+    Boolean values are stored directly inside a @ref basic_json type.
+
+    @since version 1.0.0
+    */
+    using boolean_t = BooleanType;
+
+    /*!
+    @brief a type for a number (integer)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
+
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
+
+    To store integer numbers in C++, a type is defined by the template
+    parameter @a NumberIntegerType which chooses the type to use.
+
+    #### Default type
+
+    With the default values for @a NumberIntegerType (`int64_t`), the default
+    value for @a number_integer_t is:
+
+    @code {.cpp}
+    int64_t
+    @endcode
+
+    #### Default behavior
+
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in integer literals lead to an interpretation as octal
+      number. Internally, the value will be stored as decimal number. For
+      instance, the C++ integer literal `010` will be serialized to `8`.
+      During deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the range and precision of numbers.
+
+    When the default type is used, the maximal integer number that can be
+    stored is `9223372036854775807` (INT64_MAX) and the minimal integer number
+    that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers
+    that are out of range will yield over/underflow when used in a
+    constructor. During deserialization, too large or small integer numbers
+    will be automatically be stored as @ref number_unsigned_t or @ref
+    number_float_t.
+
+    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    > Note that when such software is used, numbers that are integers and are
+    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
+    > that implementations will agree exactly on their numeric values.
+
+    As this range is a subrange of the exactly supported range [INT64_MIN,
+    INT64_MAX], this class's integer type is interoperable.
+
+    #### Storage
+
+    Integer number values are stored directly inside a @ref basic_json type.
+
+    @sa @ref number_float_t -- type for number values (floating-point)
+
+    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+
+    @since version 1.0.0
+    */
+    using number_integer_t = NumberIntegerType;
+
+    /*!
+    @brief a type for a number (unsigned)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
+
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
+
+    To store unsigned integer numbers in C++, a type is defined by the
+    template parameter @a NumberUnsignedType which chooses the type to use.
+
+    #### Default type
+
+    With the default values for @a NumberUnsignedType (`uint64_t`), the
+    default value for @a number_unsigned_t is:
+
+    @code {.cpp}
+    uint64_t
+    @endcode
+
+    #### Default behavior
+
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in integer literals lead to an interpretation as octal
+      number. Internally, the value will be stored as decimal number. For
+      instance, the C++ integer literal `010` will be serialized to `8`.
+      During deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the range and precision of numbers.
+
+    When the default type is used, the maximal integer number that can be
+    stored is `18446744073709551615` (UINT64_MAX) and the minimal integer
+    number that can be stored is `0`. Integer numbers that are out of range
+    will yield over/underflow when used in a constructor. During
+    deserialization, too large or small integer numbers will be automatically
+    be stored as @ref number_integer_t or @ref number_float_t.
+
+    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    > Note that when such software is used, numbers that are integers and are
+    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
+    > that implementations will agree exactly on their numeric values.
+
+    As this range is a subrange (when considered in conjunction with the
+    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
+    this class's integer type is interoperable.
+
+    #### Storage
+
+    Integer number values are stored directly inside a @ref basic_json type.
+
+    @sa @ref number_float_t -- type for number values (floating-point)
+    @sa @ref number_integer_t -- type for number values (integer)
+
+    @since version 2.0.0
+    */
+    using number_unsigned_t = NumberUnsignedType;
+
+    /*!
+    @brief a type for a number (floating-point)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
+
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
+
+    To store floating-point numbers in C++, a type is defined by the template
+    parameter @a NumberFloatType which chooses the type to use.
+
+    #### Default type
+
+    With the default values for @a NumberFloatType (`double`), the default
+    value for @a number_float_t is:
+
+    @code {.cpp}
+    double
+    @endcode
+
+    #### Default behavior
+
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in floating-point literals will be ignored. Internally,
+      the value will be stored as decimal number. For instance, the C++
+      floating-point literal `01.2` will be serialized to `1.2`. During
+      deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    > This specification allows implementations to set limits on the range and
+    > precision of numbers accepted. Since software that implements IEEE
+    > 754-2008 binary64 (double precision) numbers is generally available and
+    > widely used, good interoperability can be achieved by implementations
+    > that expect no more precision or range than these provide, in the sense
+    > that implementations will approximate JSON numbers within the expected
+    > precision.
+
+    This implementation does exactly follow this approach, as it uses double
+    precision floating-point numbers. Note values smaller than
+    `-1.79769313486232e+308` and values greater than `1.79769313486232e+308`
+    will be stored as NaN internally and be serialized to `null`.
+
+    #### Storage
+
+    Floating-point number values are stored directly inside a @ref basic_json
+    type.
+
+    @sa @ref number_integer_t -- type for number values (integer)
+
+    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+
+    @since version 1.0.0
+    */
+    using number_float_t = NumberFloatType;
+
+    /// @}
+
+
+    ///////////////////////////
+    // JSON type enumeration //
+    ///////////////////////////
+
+    /*!
+    @brief the JSON type enumeration
+
+    This enumeration collects the different JSON types. It is internally used
+    to distinguish the stored values, and the functions @ref is_null(), @ref
+    is_object(), @ref is_array(), @ref is_string(), @ref is_boolean(), @ref
+    is_number() (with @ref is_number_integer(), @ref is_number_unsigned(), and
+    @ref is_number_float()), @ref is_discarded(), @ref is_primitive(), and
+    @ref is_structured() rely on it.
+
+    @note There are three enumeration entries (number_integer,
+    number_unsigned, and number_float), because the library distinguishes
+    these three types for numbers: @ref number_unsigned_t is used for unsigned
+    integers, @ref number_integer_t is used for signed integers, and @ref
+    number_float_t is used for floating-point numbers or to approximate
+    integers which do not fit in the limits of their respective type.
+
+    @sa @ref basic_json(const value_t value_type) -- create a JSON value with
+    the default value for a given type
+
+    @since version 1.0.0
+    */
+    enum class value_t : uint8_t
+    {
+        null,            ///< null value
+        object,          ///< object (unordered set of name/value pairs)
+        array,           ///< array (ordered collection of values)
+        string,          ///< string value
+        boolean,         ///< boolean value
+        number_integer,  ///< number value (signed integer)
+        number_unsigned, ///< number value (unsigned integer)
+        number_float,    ///< number value (floating-point)
+        discarded        ///< discarded by the the parser callback function
+    };
+
+
+  private:
+
+    /// helper for exception-safe object creation
+    template<typename T, typename... Args>
+    static T* create(Args&& ... args)
+    {
+        AllocatorType<T> alloc;
+        auto deleter = [&](T * object)
+        {
+            alloc.deallocate(object, 1);
+        };
+        std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
+        alloc.construct(object.get(), std::forward<Args>(args)...);
+        assert(object.get() != nullptr);
+        return object.release();
+    }
+
+    ////////////////////////
+    // JSON value storage //
+    ////////////////////////
+
+    /*!
+    @brief a JSON value
+
+    The actual storage for a JSON value of the @ref basic_json class. This
+    union combines the different storage types for the JSON value types
+    defined in @ref value_t.
+
+    JSON type | value_t type    | used type
+    --------- | --------------- | ------------------------
+    object    | object          | pointer to @ref object_t
+    array     | array           | pointer to @ref array_t
+    string    | string          | pointer to @ref string_t
+    boolean   | boolean         | @ref boolean_t
+    number    | number_integer  | @ref number_integer_t
+    number    | number_unsigned | @ref number_unsigned_t
+    number    | number_float    | @ref number_float_t
+    null      | null            | *no value is stored*
+
+    @note Variable-length types (objects, arrays, and strings) are stored as
+    pointers. The size of the union should not exceed 64 bits if the default
+    value types are used.
+
+    @since version 1.0.0
+    */
+    union json_value
+    {
+        /// object (stored with pointer to save storage)
+        object_t* object;
+        /// array (stored with pointer to save storage)
+        array_t* array;
+        /// string (stored with pointer to save storage)
+        string_t* string;
+        /// boolean
+        boolean_t boolean;
+        /// number (integer)
+        number_integer_t number_integer;
+        /// number (unsigned integer)
+        number_unsigned_t number_unsigned;
+        /// number (floating-point)
+        number_float_t number_float;
+
+        /// default constructor (for null values)
+        json_value() = default;
+        /// constructor for booleans
+        json_value(boolean_t v) noexcept : boolean(v) {}
+        /// constructor for numbers (integer)
+        json_value(number_integer_t v) noexcept : number_integer(v) {}
+        /// constructor for numbers (unsigned)
+        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
+        /// constructor for numbers (floating-point)
+        json_value(number_float_t v) noexcept : number_float(v) {}
+        /// constructor for empty values of a given type
+        json_value(value_t t)
+        {
+            switch (t)
+            {
+                case value_t::object:
+                {
+                    object = create<object_t>();
+                    break;
+                }
+
+                case value_t::array:
+                {
+                    array = create<array_t>();
+                    break;
+                }
+
+                case value_t::string:
+                {
+                    string = create<string_t>("");
+                    break;
+                }
+
+                case value_t::boolean:
+                {
+                    boolean = boolean_t(false);
+                    break;
+                }
+
+                case value_t::number_integer:
+                {
+                    number_integer = number_integer_t(0);
+                    break;
+                }
+
+                case value_t::number_unsigned:
+                {
+                    number_unsigned = number_unsigned_t(0);
+                    break;
+                }
+
+                case value_t::number_float:
+                {
+                    number_float = number_float_t(0.0);
+                    break;
+                }
+
+                default:
+                {
+                    break;
+                }
+            }
+        }
+
+        /// constructor for strings
+        json_value(const string_t& value)
+        {
+            string = create<string_t>(value);
+        }
+
+        /// constructor for objects
+        json_value(const object_t& value)
+        {
+            object = create<object_t>(value);
+        }
+
+        /// constructor for arrays
+        json_value(const array_t& value)
+        {
+            array = create<array_t>(value);
+        }
+    };
+
+    /*!
+    @brief checks the class invariants
+
+    This function asserts the class invariants. It needs to be called at the
+    end of every constructor to make sure that created objects respect the
+    invariant. Furthermore, it has to be called each time the type of a JSON
+    value is changed, because the invariant expresses a relationship between
+    @a m_type and @a m_value.
+    */
+    void assert_invariant() const
+    {
+        assert(m_type != value_t::object or m_value.object != nullptr);
+        assert(m_type != value_t::array or m_value.array != nullptr);
+        assert(m_type != value_t::string or m_value.string != nullptr);
+    }
+
+  public:
+    //////////////////////////
+    // JSON parser callback //
+    //////////////////////////
+
+    /*!
+    @brief JSON callback events
+
+    This enumeration lists the parser events that can trigger calling a
+    callback function of type @ref parser_callback_t during parsing.
+
+    @image html callback_events.png "Example when certain parse events are triggered"
+
+    @since version 1.0.0
+    */
+    enum class parse_event_t : uint8_t
+    {
+        /// the parser read `{` and started to process a JSON object
+        object_start,
+        /// the parser read `}` and finished processing a JSON object
+        object_end,
+        /// the parser read `[` and started to process a JSON array
+        array_start,
+        /// the parser read `]` and finished processing a JSON array
+        array_end,
+        /// the parser read a key of a value in an object
+        key,
+        /// the parser finished reading a JSON value
+        value
+    };
+
+    /*!
+    @brief per-element parser callback type
+
+    With a parser callback function, the result of parsing a JSON text can be
+    influenced. When passed to @ref parse(std::istream&, const
+    parser_callback_t) or @ref parse(const string_t&, const parser_callback_t),
+    it is called on certain events (passed as @ref parse_event_t via parameter
+    @a event) with a set recursion depth @a depth and context JSON value
+    @a parsed. The return value of the callback function is a boolean
+    indicating whether the element that emitted the callback shall be kept or
+    not.
+
+    We distinguish six scenarios (determined by the event type) in which the
+    callback function can be called. The following table describes the values
+    of the parameters @a depth, @a event, and @a parsed.
+
+    parameter @a event | description | parameter @a depth | parameter @a parsed
+    ------------------ | ----------- | ------------------ | -------------------
+    parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded
+    parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key
+    parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object
+    parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded
+    parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
+    parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
+
+    @image html callback_events.png "Example when certain parse events are triggered"
+
+    Discarding a value (i.e., returning `false`) has different effects
+    depending on the context in which function was called:
+
+    - Discarded values in structured types are skipped. That is, the parser
+      will behave as if the discarded value was never read.
+    - In case a value outside a structured type is skipped, it is replaced
+      with `null`. This case happens if the top-level element is skipped.
+
+    @param[in] depth  the depth of the recursion during parsing
+
+    @param[in] event  an event of type parse_event_t indicating the context in
+    the callback function has been called
+
+    @param[in,out] parsed  the current intermediate parse result; note that
+    writing to this value has no effect for parse_event_t::key events
+
+    @return Whether the JSON value which called the function during parsing
+    should be kept (`true`) or not (`false`). In the latter case, it is either
+    skipped completely or replaced by an empty discarded object.
+
+    @sa @ref parse(std::istream&, parser_callback_t) or
+    @ref parse(const string_t&, parser_callback_t) for examples
+
+    @since version 1.0.0
+    */
+    using parser_callback_t = std::function<bool(int depth,
+                              parse_event_t event,
+                              basic_json& parsed)>;
+
+
+    //////////////////
+    // constructors //
+    //////////////////
+
+    /// @name constructors and destructors
+    /// Constructors of class @ref basic_json, copy/move constructor, copy
+    /// assignment, static functions creating objects, and the destructor.
+    /// @{
+
+    /*!
+    @brief create an empty value with a given type
+
+    Create an empty JSON value with a given type. The value will be default
+    initialized with an empty value which depends on the type:
+
+    Value type  | initial value
+    ----------- | -------------
+    null        | `null`
+    boolean     | `false`
+    string      | `""`
+    number      | `0`
+    object      | `{}`
+    array       | `[]`
+
+    @param[in] value_type  the type of the value to create
+
+    @complexity Constant.
+
+    @throw std::bad_alloc if allocation for object, array, or string value
+    fails
+
+    @liveexample{The following code shows the constructor for different @ref
+    value_t values,basic_json__value_t}
+
+    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
+    @sa @ref basic_json(boolean_t value) -- create a boolean value
+    @sa @ref basic_json(const string_t&) -- create a string value
+    @sa @ref basic_json(const object_t&) -- create a object value
+    @sa @ref basic_json(const array_t&) -- create a array value
+    @sa @ref basic_json(const number_float_t) -- create a number
+    (floating-point) value
+    @sa @ref basic_json(const number_integer_t) -- create a number (integer)
+    value
+    @sa @ref basic_json(const number_unsigned_t) -- create a number (unsigned)
+    value
+
+    @since version 1.0.0
+    */
+    basic_json(const value_t value_type)
+        : m_type(value_type), m_value(value_type)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a null object (implicitly)
+
+    Create a `null` JSON value. This is the implicit version of the `null`
+    value constructor as it takes no parameters.
+
+    @note The class invariant is satisfied, because it poses no requirements
+    for null values.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this constructor never throws
+    exceptions.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - As postcondition, it holds: `basic_json().empty() == true`.
+
+    @liveexample{The following code shows the constructor for a `null` JSON
+    value.,basic_json}
+
+    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
+
+    @since version 1.0.0
+    */
+    basic_json() = default;
+
+    /*!
+    @brief create a null object (explicitly)
+
+    Create a `null` JSON value. This is the explicitly version of the `null`
+    value constructor as it takes a null pointer as parameter. It allows to
+    create `null` values by explicitly assigning a `nullptr` to a JSON value.
+    The passed null pointer itself is not read -- it is only used to choose
+    the right constructor.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this constructor never throws
+    exceptions.
+
+    @liveexample{The following code shows the constructor with null pointer
+    parameter.,basic_json__nullptr_t}
+
+    @sa @ref basic_json() -- default constructor (implicitly creating a `null`
+    value)
+
+    @since version 1.0.0
+    */
+    basic_json(std::nullptr_t) noexcept
+        : basic_json(value_t::null)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an object (explicit)
+
+    Create an object JSON value with a given content.
+
+    @param[in] val  a value for the object
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for object value fails
+
+    @liveexample{The following code shows the constructor with an @ref
+    object_t parameter.,basic_json__object_t}
+
+    @sa @ref basic_json(const CompatibleObjectType&) -- create an object value
+    from a compatible STL container
+
+    @since version 1.0.0
+    */
+    basic_json(const object_t& val)
+        : m_type(value_t::object), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an object (implicit)
+
+    Create an object JSON value with a given content. This constructor allows
+    any type @a CompatibleObjectType that can be used to construct values of
+    type @ref object_t.
+
+    @tparam CompatibleObjectType An object type whose `key_type` and
+    `value_type` is compatible to @ref object_t. Examples include `std::map`,
+    `std::unordered_map`, `std::multimap`, and `std::unordered_multimap` with
+    a `key_type` of `std::string`, and a `value_type` from which a @ref
+    basic_json value can be constructed.
+
+    @param[in] val  a value for the object
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for object value fails
+
+    @liveexample{The following code shows the constructor with several
+    compatible object type parameters.,basic_json__CompatibleObjectType}
+
+    @sa @ref basic_json(const object_t&) -- create an object value
+
+    @since version 1.0.0
+    */
+    template <class CompatibleObjectType, typename
+              std::enable_if<
+                  std::is_constructible<typename object_t::key_type, typename CompatibleObjectType::key_type>::value and
+                  std::is_constructible<basic_json, typename CompatibleObjectType::mapped_type>::value, int>::type
+              = 0>
+    basic_json(const CompatibleObjectType& val)
+        : m_type(value_t::object)
+    {
+        using std::begin;
+        using std::end;
+        m_value.object = create<object_t>(begin(val), end(val));
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an array (explicit)
+
+    Create an array JSON value with a given content.
+
+    @param[in] val  a value for the array
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for array value fails
+
+    @liveexample{The following code shows the constructor with an @ref array_t
+    parameter.,basic_json__array_t}
+
+    @sa @ref basic_json(const CompatibleArrayType&) -- create an array value
+    from a compatible STL containers
+
+    @since version 1.0.0
+    */
+    basic_json(const array_t& val)
+        : m_type(value_t::array), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an array (implicit)
+
+    Create an array JSON value with a given content. This constructor allows
+    any type @a CompatibleArrayType that can be used to construct values of
+    type @ref array_t.
+
+    @tparam CompatibleArrayType An object type whose `value_type` is
+    compatible to @ref array_t. Examples include `std::vector`, `std::deque`,
+    `std::list`, `std::forward_list`, `std::array`, `std::set`,
+    `std::unordered_set`, `std::multiset`, and `unordered_multiset` with a
+    `value_type` from which a @ref basic_json value can be constructed.
+
+    @param[in] val  a value for the array
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for array value fails
+
+    @liveexample{The following code shows the constructor with several
+    compatible array type parameters.,basic_json__CompatibleArrayType}
+
+    @sa @ref basic_json(const array_t&) -- create an array value
+
+    @since version 1.0.0
+    */
+    template <class CompatibleArrayType, typename
+              std::enable_if<
+                  not std::is_same<CompatibleArrayType, typename basic_json_t::iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename basic_json_t::reverse_iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_reverse_iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename array_t::iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename array_t::const_iterator>::value and
+                  std::is_constructible<basic_json, typename CompatibleArrayType::value_type>::value, int>::type
+              = 0>
+    basic_json(const CompatibleArrayType& val)
+        : m_type(value_t::array)
+    {
+        using std::begin;
+        using std::end;
+        m_value.array = create<array_t>(begin(val), end(val));
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a string (explicit)
+
+    Create an string JSON value with a given content.
+
+    @param[in] val  a value for the string
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for string value fails
+
+    @liveexample{The following code shows the constructor with an @ref
+    string_t parameter.,basic_json__string_t}
+
+    @sa @ref basic_json(const typename string_t::value_type*) -- create a
+    string value from a character pointer
+    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
+    from a compatible string container
+
+    @since version 1.0.0
+    */
+    basic_json(const string_t& val)
+        : m_type(value_t::string), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a string (explicit)
+
+    Create a string JSON value with a given content.
+
+    @param[in] val  a literal value for the string
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for string value fails
+
+    @liveexample{The following code shows the constructor with string literal
+    parameter.,basic_json__string_t_value_type}
+
+    @sa @ref basic_json(const string_t&) -- create a string value
+    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
+    from a compatible string container
+
+    @since version 1.0.0
+    */
+    basic_json(const typename string_t::value_type* val)
+        : basic_json(string_t(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a string (implicit)
+
+    Create a string JSON value with a given content.
+
+    @param[in] val  a value for the string
+
+    @tparam CompatibleStringType an string type which is compatible to @ref
+    string_t, for instance `std::string`.
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for string value fails
+
+    @liveexample{The following code shows the construction of a string value
+    from a compatible type.,basic_json__CompatibleStringType}
+
+    @sa @ref basic_json(const string_t&) -- create a string value
+    @sa @ref basic_json(const typename string_t::value_type*) -- create a
+    string value from a character pointer
+
+    @since version 1.0.0
+    */
+    template <class CompatibleStringType, typename
+              std::enable_if<
+                  std::is_constructible<string_t, CompatibleStringType>::value, int>::type
+              = 0>
+    basic_json(const CompatibleStringType& val)
+        : basic_json(string_t(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a boolean (explicit)
+
+    Creates a JSON boolean type from a given value.
+
+    @param[in] val  a boolean value to store
+
+    @complexity Constant.
+
+    @liveexample{The example below demonstrates boolean
+    values.,basic_json__boolean_t}
+
+    @since version 1.0.0
+    */
+    basic_json(boolean_t val) noexcept
+        : m_type(value_t::boolean), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an integer number (explicit)
+
+    Create an integer number JSON value with a given content.
+
+    @tparam T A helper type to remove this function via SFINAE in case @ref
+    number_integer_t is the same as `int`. In this case, this constructor
+    would have the same signature as @ref basic_json(const int value). Note
+    the helper type @a T is not visible in this constructor's interface.
+
+    @param[in] val  an integer to create a JSON number from
+
+    @complexity Constant.
+
+    @liveexample{The example below shows the construction of an integer
+    number value.,basic_json__number_integer_t}
+
+    @sa @ref basic_json(const int) -- create a number value (integer)
+    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
+    value (integer) from a compatible number type
+
+    @since version 1.0.0
+    */
+    template<typename T,
+             typename std::enable_if<
+                 not (std::is_same<T, int>::value)
+                 and std::is_same<T, number_integer_t>::value
+                 , int>::type
+             = 0>
+    basic_json(const number_integer_t val) noexcept
+        : m_type(value_t::number_integer), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an integer number from an enum type (explicit)
+
+    Create an integer number JSON value with a given content.
+
+    @param[in] val  an integer to create a JSON number from
+
+    @note This constructor allows to pass enums directly to a constructor. As
+    C++ has no way of specifying the type of an anonymous enum explicitly, we
+    can only rely on the fact that such values implicitly convert to int. As
+    int may already be the same type of number_integer_t, we may need to
+    switch off the constructor @ref basic_json(const number_integer_t).
+
+    @complexity Constant.
+
+    @liveexample{The example below shows the construction of an integer
+    number value from an anonymous enum.,basic_json__const_int}
+
+    @sa @ref basic_json(const number_integer_t) -- create a number value
+    (integer)
+    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
+    value (integer) from a compatible number type
+
+    @since version 1.0.0
+    */
+    basic_json(const int val) noexcept
+        : m_type(value_t::number_integer),
+          m_value(static_cast<number_integer_t>(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an integer number (implicit)
+
+    Create an integer number JSON value with a given content. This constructor
+    allows any type @a CompatibleNumberIntegerType that can be used to
+    construct values of type @ref number_integer_t.
+
+    @tparam CompatibleNumberIntegerType An integer type which is compatible to
+    @ref number_integer_t. Examples include the types `int`, `int32_t`,
+    `long`, and `short`.
+
+    @param[in] val  an integer to create a JSON number from
+
+    @complexity Constant.
+
+    @liveexample{The example below shows the construction of several integer
+    number values from compatible
+    types.,basic_json__CompatibleIntegerNumberType}
+
+    @sa @ref basic_json(const number_integer_t) -- create a number value
+    (integer)
+    @sa @ref basic_json(const int) -- create a number value (integer)
+
+    @since version 1.0.0
+    */
+    template<typename CompatibleNumberIntegerType, typename
+             std::enable_if<
+                 std::is_constructible<number_integer_t, CompatibleNumberIntegerType>::value and
+                 std::numeric_limits<CompatibleNumberIntegerType>::is_integer and
+                 std::numeric_limits<CompatibleNumberIntegerType>::is_signed,
+                 CompatibleNumberIntegerType>::type
+             = 0>
+    basic_json(const CompatibleNumberIntegerType val) noexcept
+        : m_type(value_t::number_integer),
+          m_value(static_cast<number_integer_t>(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an unsigned integer number (explicit)
+
+    Create an unsigned integer number JSON value with a given content.
+
+    @tparam T  helper type to compare number_unsigned_t and unsigned int (not
+    visible in) the interface.
+
+    @param[in] val  an integer to create a JSON number from
+
+    @complexity Constant.
+
+    @sa @ref basic_json(const CompatibleNumberUnsignedType) -- create a number
+    value (unsigned integer) from a compatible number type
+
+    @since version 2.0.0
+    */
+    template<typename T,
+             typename std::enable_if<
+                 not (std::is_same<T, int>::value)
+                 and std::is_same<T, number_unsigned_t>::value
+                 , int>::type
+             = 0>
+    basic_json(const number_unsigned_t val) noexcept
+        : m_type(value_t::number_unsigned), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an unsigned number (implicit)
+
+    Create an unsigned number JSON value with a given content. This
+    constructor allows any type @a CompatibleNumberUnsignedType that can be
+    used to construct values of type @ref number_unsigned_t.
+
+    @tparam CompatibleNumberUnsignedType An integer type which is compatible
+    to @ref number_unsigned_t. Examples may include the types `unsigned int`,
+    `uint32_t`, or `unsigned short`.
+
+    @param[in] val  an unsigned integer to create a JSON number from
+
+    @complexity Constant.
+
+    @sa @ref basic_json(const number_unsigned_t) -- create a number value
+    (unsigned)
+
+    @since version 2.0.0
+    */
+    template <typename CompatibleNumberUnsignedType, typename
+              std::enable_if <
+                  std::is_constructible<number_unsigned_t, CompatibleNumberUnsignedType>::value and
+                  std::numeric_limits<CompatibleNumberUnsignedType>::is_integer and
+                  not std::numeric_limits<CompatibleNumberUnsignedType>::is_signed,
+                  CompatibleNumberUnsignedType>::type
+              = 0>
+    basic_json(const CompatibleNumberUnsignedType val) noexcept
+        : m_type(value_t::number_unsigned),
+          m_value(static_cast<number_unsigned_t>(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a floating-point number (explicit)
+
+    Create a floating-point number JSON value with a given content.
+
+    @param[in] val  a floating-point value to create a JSON number from
+
+    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
+    disallows NaN values:
+    > Numeric values that cannot be represented in the grammar below (such as
+    > Infinity and NaN) are not permitted.
+    In case the parameter @a val is not a number, a JSON null value is created
+    instead.
+
+    @complexity Constant.
+
+    @liveexample{The following example creates several floating-point
+    values.,basic_json__number_float_t}
+
+    @sa @ref basic_json(const CompatibleNumberFloatType) -- create a number
+    value (floating-point) from a compatible number type
+
+    @since version 1.0.0
+    */
+    basic_json(const number_float_t val) noexcept
+        : m_type(value_t::number_float), m_value(val)
+    {
+        // replace infinity and NAN by null
+        if (not std::isfinite(val))
+        {
+            m_type = value_t::null;
+            m_value = json_value();
+        }
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an floating-point number (implicit)
+
+    Create an floating-point number JSON value with a given content. This
+    constructor allows any type @a CompatibleNumberFloatType that can be used
+    to construct values of type @ref number_float_t.
+
+    @tparam CompatibleNumberFloatType A floating-point type which is
+    compatible to @ref number_float_t. Examples may include the types `float`
+    or `double`.
+
+    @param[in] val  a floating-point to create a JSON number from
+
+    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
+    disallows NaN values:
+    > Numeric values that cannot be represented in the grammar below (such as
+    > Infinity and NaN) are not permitted.
+    In case the parameter @a val is not a number, a JSON null value is
+    created instead.
+
+    @complexity Constant.
+
+    @liveexample{The example below shows the construction of several
+    floating-point number values from compatible
+    types.,basic_json__CompatibleNumberFloatType}
+
+    @sa @ref basic_json(const number_float_t) -- create a number value
+    (floating-point)
+
+    @since version 1.0.0
+    */
+    template<typename CompatibleNumberFloatType, typename = typename
+             std::enable_if<
+                 std::is_constructible<number_float_t, CompatibleNumberFloatType>::value and
+                 std::is_floating_point<CompatibleNumberFloatType>::value>::type
+             >
+    basic_json(const CompatibleNumberFloatType val) noexcept
+        : basic_json(number_float_t(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a container (array or object) from an initializer list
+
+    Creates a JSON value of type array or object from the passed initializer
+    list @a init. In case @a type_deduction is `true` (default), the type of
+    the JSON value to be created is deducted from the initializer list @a init
+    according to the following rules:
+
+    1. If the list is empty, an empty JSON object value `{}` is created.
+    2. If the list consists of pairs whose first element is a string, a JSON
+       object value is created where the first elements of the pairs are
+       treated as keys and the second elements are as values.
+    3. In all other cases, an array is created.
+
+    The rules aim to create the best fit between a C++ initializer list and
+    JSON values. The rationale is as follows:
+
+    1. The empty initializer list is written as `{}` which is exactly an empty
+       JSON object.
+    2. C++ has now way of describing mapped types other than to list a list of
+       pairs. As JSON requires that keys must be of type string, rule 2 is the
+       weakest constraint one can pose on initializer lists to interpret them
+       as an object.
+    3. In all other cases, the initializer list could not be interpreted as
+       JSON object type, so interpreting it as JSON array type is safe.
+
+    With the rules described above, the following JSON values cannot be
+    expressed by an initializer list:
+
+    - the empty array (`[]`): use @ref array(std::initializer_list<basic_json>)
+      with an empty initializer list in this case
+    - arrays whose elements satisfy rule 2: use @ref
+      array(std::initializer_list<basic_json>) with the same initializer list
+      in this case
+
+    @note When used without parentheses around an empty initializer list, @ref
+    basic_json() is called instead of this function, yielding the JSON null
+    value.
+
+    @param[in] init  initializer list with JSON values
+
+    @param[in] type_deduction internal parameter; when set to `true`, the type
+    of the JSON value is deducted from the initializer list @a init; when set
+    to `false`, the type provided via @a manual_type is forced. This mode is
+    used by the functions @ref array(std::initializer_list<basic_json>) and
+    @ref object(std::initializer_list<basic_json>).
+
+    @param[in] manual_type internal parameter; when @a type_deduction is set
+    to `false`, the created JSON value will use the provided type (only @ref
+    value_t::array and @ref value_t::object are valid); when @a type_deduction
+    is set to `true`, this parameter has no effect
+
+    @throw std::domain_error if @a type_deduction is `false`, @a manual_type
+    is `value_t::object`, but @a init contains an element which is not a pair
+    whose first element is a string; example: `"cannot create object from
+    initializer list"`
+
+    @complexity Linear in the size of the initializer list @a init.
+
+    @liveexample{The example below shows how JSON values are created from
+    initializer lists.,basic_json__list_init_t}
+
+    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
+    value from an initializer list
+    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
+    value from an initializer list
+
+    @since version 1.0.0
+    */
+    basic_json(std::initializer_list<basic_json> init,
+               bool type_deduction = true,
+               value_t manual_type = value_t::array)
+    {
+        // check if each element is an array with two elements whose first
+        // element is a string
+        bool is_an_object = std::all_of(init.begin(), init.end(),
+                                        [](const basic_json & element)
+        {
+            return element.is_array() and element.size() == 2 and element[0].is_string();
+        });
+
+        // adjust type if type deduction is not wanted
+        if (not type_deduction)
+        {
+            // if array is wanted, do not create an object though possible
+            if (manual_type == value_t::array)
+            {
+                is_an_object = false;
+            }
+
+            // if object is wanted but impossible, throw an exception
+            if (manual_type == value_t::object and not is_an_object)
+            {
+                throw std::domain_error("cannot create object from initializer list");
+            }
+        }
+
+        if (is_an_object)
+        {
+            // the initializer list is a list of pairs -> create object
+            m_type = value_t::object;
+            m_value = value_t::object;
+
+            std::for_each(init.begin(), init.end(), [this](const basic_json & element)
+            {
+                m_value.object->emplace(*(element[0].m_value.string), element[1]);
+            });
+        }
+        else
+        {
+            // the initializer list describes an array -> create array
+            m_type = value_t::array;
+            m_value.array = create<array_t>(init);
+        }
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief explicitly create an array from an initializer list
+
+    Creates a JSON array value from a given initializer list. That is, given a
+    list of values `a, b, c`, creates the JSON value `[a, b, c]`. If the
+    initializer list is empty, the empty array `[]` is created.
+
+    @note This function is only needed to express two edge cases that cannot
+    be realized with the initializer list constructor (@ref
+    basic_json(std::initializer_list<basic_json>, bool, value_t)). These cases
+    are:
+    1. creating an array whose elements are all pairs whose first element is a
+    string -- in this case, the initializer list constructor would create an
+    object, taking the first elements as keys
+    2. creating an empty array -- passing the empty initializer list to the
+    initializer list constructor yields an empty object
+
+    @param[in] init  initializer list with JSON values to create an array from
+    (optional)
+
+    @return JSON array value
+
+    @complexity Linear in the size of @a init.
+
+    @liveexample{The following code shows an example for the `array`
+    function.,array}
+
+    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
+    create a JSON value from an initializer list
+    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
+    value from an initializer list
+
+    @since version 1.0.0
+    */
+    static basic_json array(std::initializer_list<basic_json> init =
+                                std::initializer_list<basic_json>())
+    {
+        return basic_json(init, false, value_t::array);
+    }
+
+    /*!
+    @brief explicitly create an object from an initializer list
+
+    Creates a JSON object value from a given initializer list. The initializer
+    lists elements must be pairs, and their first elements must be strings. If
+    the initializer list is empty, the empty object `{}` is created.
+
+    @note This function is only added for symmetry reasons. In contrast to the
+    related function @ref array(std::initializer_list<basic_json>), there are
+    no cases which can only be expressed by this function. That is, any
+    initializer list @a init can also be passed to the initializer list
+    constructor @ref basic_json(std::initializer_list<basic_json>, bool,
+    value_t).
+
+    @param[in] init  initializer list to create an object from (optional)
+
+    @return JSON object value
+
+    @throw std::domain_error if @a init is not a pair whose first elements are
+    strings; thrown by
+    @ref basic_json(std::initializer_list<basic_json>, bool, value_t)
+
+    @complexity Linear in the size of @a init.
+
+    @liveexample{The following code shows an example for the `object`
+    function.,object}
+
+    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
+    create a JSON value from an initializer list
+    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
+    value from an initializer list
+
+    @since version 1.0.0
+    */
+    static basic_json object(std::initializer_list<basic_json> init =
+                                 std::initializer_list<basic_json>())
+    {
+        return basic_json(init, false, value_t::object);
+    }
+
+    /*!
+    @brief construct an array with count copies of given value
+
+    Constructs a JSON array value by creating @a cnt copies of a passed value.
+    In case @a cnt is `0`, an empty array is created. As postcondition,
+    `std::distance(begin(),end()) == cnt` holds.
+
+    @param[in] cnt  the number of JSON copies of @a val to create
+    @param[in] val  the JSON value to copy
+
+    @complexity Linear in @a cnt.
+
+    @liveexample{The following code shows examples for the @ref
+    basic_json(size_type\, const basic_json&)
+    constructor.,basic_json__size_type_basic_json}
+
+    @since version 1.0.0
+    */
+    basic_json(size_type cnt, const basic_json& val)
+        : m_type(value_t::array)
+    {
+        m_value.array = create<array_t>(cnt, val);
+        assert_invariant();
+    }
+
+    /*!
+    @brief construct a JSON container given an iterator range
+
+    Constructs the JSON value with the contents of the range `[first, last)`.
+    The semantics depends on the different types a JSON value can have:
+    - In case of primitive types (number, boolean, or string), @a first must
+      be `begin()` and @a last must be `end()`. In this case, the value is
+      copied. Otherwise, std::out_of_range is thrown.
+    - In case of structured types (array, object), the constructor behaves as
+      similar versions for `std::vector`.
+    - In case of a null type, std::domain_error is thrown.
+
+    @tparam InputIT an input iterator type (@ref iterator or @ref
+    const_iterator)
+
+    @param[in] first begin of the range to copy from (included)
+    @param[in] last end of the range to copy from (excluded)
+
+    @pre Iterators @a first and @a last must be initialized.
+
+    @throw std::domain_error if iterators are not compatible; that is, do not
+    belong to the same JSON value; example: `"iterators are not compatible"`
+    @throw std::out_of_range if iterators are for a primitive type (number,
+    boolean, or string) where an out of range error can be detected easily;
+    example: `"iterators out of range"`
+    @throw std::bad_alloc if allocation for object, array, or string fails
+    @throw std::domain_error if called with a null value; example: `"cannot
+    use construct with iterators from null"`
+
+    @complexity Linear in distance between @a first and @a last.
+
+    @liveexample{The example below shows several ways to create JSON values by
+    specifying a subrange with iterators.,basic_json__InputIt_InputIt}
+
+    @since version 1.0.0
+    */
+    template <class InputIT, typename
+              std::enable_if<
+                  std::is_same<InputIT, typename basic_json_t::iterator>::value or
+                  std::is_same<InputIT, typename basic_json_t::const_iterator>::value
+                  , int>::type
+              = 0>
+    basic_json(InputIT first, InputIT last)
+    {
+        assert(first.m_object != nullptr);
+        assert(last.m_object != nullptr);
+
+        // make sure iterator fits the current value
+        if (first.m_object != last.m_object)
+        {
+            throw std::domain_error("iterators are not compatible");
+        }
+
+        // copy type from first iterator
+        m_type = first.m_object->m_type;
+
+        // check if iterator range is complete for primitive values
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
+            {
+                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
+                {
+                    throw std::out_of_range("iterators out of range");
+                }
+                break;
+            }
+
+            default:
+            {
+                break;
+            }
+        }
+
+        switch (m_type)
+        {
+            case value_t::number_integer:
+            {
+                m_value.number_integer = first.m_object->m_value.number_integer;
+                break;
+            }
+
+            case value_t::number_unsigned:
+            {
+                m_value.number_unsigned = first.m_object->m_value.number_unsigned;
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                m_value.number_float = first.m_object->m_value.number_float;
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                m_value.boolean = first.m_object->m_value.boolean;
+                break;
+            }
+
+            case value_t::string:
+            {
+                m_value = *first.m_object->m_value.string;
+                break;
+            }
+
+            case value_t::object:
+            {
+                m_value.object = create<object_t>(first.m_it.object_iterator, last.m_it.object_iterator);
+                break;
+            }
+
+            case value_t::array:
+            {
+                m_value.array = create<array_t>(first.m_it.array_iterator, last.m_it.array_iterator);
+                break;
+            }
+
+            default:
+            {
+                throw std::domain_error("cannot use construct with iterators from " + first.m_object->type_name());
+            }
+        }
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief construct a JSON value given an input stream
+
+    @param[in,out] i  stream to read a serialized JSON value from
+    @param[in] cb a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates constructing a JSON value from
+    a `std::stringstream` with and without callback
+    function.,basic_json__istream}
+
+    @since version 2.0.0
+    */
+    explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)
+    {
+        *this = parser(i, cb).parse();
+        assert_invariant();
+    }
+
+    ///////////////////////////////////////
+    // other constructors and destructor //
+    ///////////////////////////////////////
+
+    /*!
+    @brief copy constructor
+
+    Creates a copy of a given JSON value.
+
+    @param[in] other  the JSON value to copy
+
+    @complexity Linear in the size of @a other.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
+    - As postcondition, it holds: `other == basic_json(other)`.
+
+    @throw std::bad_alloc if allocation for object, array, or string fails.
+
+    @liveexample{The following code shows an example for the copy
+    constructor.,basic_json__basic_json}
+
+    @since version 1.0.0
+    */
+    basic_json(const basic_json& other)
+        : m_type(other.m_type)
+    {
+        // check of passed value is valid
+        other.assert_invariant();
+
+        switch (m_type)
+        {
+            case value_t::object:
+            {
+                m_value = *other.m_value.object;
+                break;
+            }
+
+            case value_t::array:
+            {
+                m_value = *other.m_value.array;
+                break;
+            }
+
+            case value_t::string:
+            {
+                m_value = *other.m_value.string;
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                m_value = other.m_value.boolean;
+                break;
+            }
+
+            case value_t::number_integer:
+            {
+                m_value = other.m_value.number_integer;
+                break;
+            }
+
+            case value_t::number_unsigned:
+            {
+                m_value = other.m_value.number_unsigned;
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                m_value = other.m_value.number_float;
+                break;
+            }
+
+            default:
+            {
+                break;
+            }
+        }
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief move constructor
+
+    Move constructor. Constructs a JSON value with the contents of the given
+    value @a other using move semantics. It "steals" the resources from @a
+    other and leaves it as JSON null value.
+
+    @param[in,out] other  value to move to this object
+
+    @post @a other is a JSON null value
+
+    @complexity Constant.
+
+    @liveexample{The code below shows the move constructor explicitly called
+    via std::move.,basic_json__moveconstructor}
+
+    @since version 1.0.0
+    */
+    basic_json(basic_json&& other) noexcept
+        : m_type(std::move(other.m_type)),
+          m_value(std::move(other.m_value))
+    {
+        // check that passed value is valid
+        other.assert_invariant();
+
+        // invalidate payload
+        other.m_type = value_t::null;
+        other.m_value = {};
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief copy assignment
+
+    Copy assignment operator. Copies a JSON value via the "copy and swap"
+    strategy: It is expressed in terms of the copy constructor, destructor,
+    and the swap() member function.
+
+    @param[in] other  value to copy from
+
+    @complexity Linear.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
+
+    @liveexample{The code below shows and example for the copy assignment. It
+    creates a copy of value `a` which is then swapped with `b`. Finally\, the
+    copy of `a` (which is the null value after the swap) is
+    destroyed.,basic_json__copyassignment}
+
+    @since version 1.0.0
+    */
+    reference& operator=(basic_json other) noexcept (
+        std::is_nothrow_move_constructible<value_t>::value and
+        std::is_nothrow_move_assignable<value_t>::value and
+        std::is_nothrow_move_constructible<json_value>::value and
+        std::is_nothrow_move_assignable<json_value>::value
+    )
+    {
+        // check that passed value is valid
+        other.assert_invariant();
+
+        using std::swap;
+        swap(m_type, other.m_type);
+        swap(m_value, other.m_value);
+
+        assert_invariant();
+        return *this;
+    }
+
+    /*!
+    @brief destructor
+
+    Destroys the JSON value and frees all allocated memory.
+
+    @complexity Linear.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
+    - All stored elements are destroyed and all memory is freed.
+
+    @since version 1.0.0
+    */
+    ~basic_json()
+    {
+        assert_invariant();
+
+        switch (m_type)
+        {
+            case value_t::object:
+            {
+                AllocatorType<object_t> alloc;
+                alloc.destroy(m_value.object);
+                alloc.deallocate(m_value.object, 1);
+                break;
+            }
+
+            case value_t::array:
+            {
+                AllocatorType<array_t> alloc;
+                alloc.destroy(m_value.array);
+                alloc.deallocate(m_value.array, 1);
+                break;
+            }
+
+            case value_t::string:
+            {
+                AllocatorType<string_t> alloc;
+                alloc.destroy(m_value.string);
+                alloc.deallocate(m_value.string, 1);
+                break;
+            }
+
+            default:
+            {
+                // all other types need no specific destructor
+                break;
+            }
+        }
+    }
+
+    /// @}
+
+  public:
+    ///////////////////////
+    // object inspection //
+    ///////////////////////
+
+    /// @name object inspection
+    /// Functions to inspect the type of a JSON value.
+    /// @{
+
+    /*!
+    @brief serialization
+
+    Serialization function for JSON values. The function tries to mimic
+    Python's `json.dumps()` function, and currently supports its @a indent
+    parameter.
+
+    @param[in] indent If indent is nonnegative, then array elements and object
+    members will be pretty-printed with that indent level. An indent level of
+    `0` will only insert newlines. `-1` (the default) selects the most compact
+    representation.
+
+    @return string containing the serialization of the JSON value
+
+    @complexity Linear.
+
+    @liveexample{The following example shows the effect of different @a indent
+    parameters to the result of the serialization.,dump}
+
+    @see https://docs.python.org/2/library/json.html#json.dump
+
+    @since version 1.0.0
+    */
+    string_t dump(const int indent = -1) const
+    {
+        std::stringstream ss;
+        // fix locale problems
+        ss.imbue(std::locale(std::locale(), new DecimalSeparator));
+
+        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
+        // string->float->string, string->double->string or string->long
+        // double->string; to be safe, we read this value from
+        // std::numeric_limits<number_float_t>::digits10
+        ss.precision(std::numeric_limits<double>::digits10);
+
+        if (indent >= 0)
+        {
+            dump(ss, true, static_cast<unsigned int>(indent));
+        }
+        else
+        {
+            dump(ss, false, 0);
+        }
+
+        return ss.str();
+    }
+
+    /*!
+    @brief return the type of the JSON value (explicit)
+
+    Return the type of the JSON value as a value from the @ref value_t
+    enumeration.
+
+    @return the type of the JSON value
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `type()` for all JSON
+    types.,type}
+
+    @since version 1.0.0
+    */
+    constexpr value_t type() const noexcept
+    {
+        return m_type;
+    }
+
+    /*!
+    @brief return whether type is primitive
+
+    This function returns true iff the JSON type is primitive (string, number,
+    boolean, or null).
+
+    @return `true` if type is primitive (string, number, boolean, or null),
+    `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_primitive()` for all JSON
+    types.,is_primitive}
+
+    @sa @ref is_structured() -- returns whether JSON value is structured
+    @sa @ref is_null() -- returns whether JSON value is `null`
+    @sa @ref is_string() -- returns whether JSON value is a string
+    @sa @ref is_boolean() -- returns whether JSON value is a boolean
+    @sa @ref is_number() -- returns whether JSON value is a number
+
+    @since version 1.0.0
+    */
+    constexpr bool is_primitive() const noexcept
+    {
+        return is_null() or is_string() or is_boolean() or is_number();
+    }
+
+    /*!
+    @brief return whether type is structured
+
+    This function returns true iff the JSON type is structured (array or
+    object).
+
+    @return `true` if type is structured (array or object), `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_structured()` for all JSON
+    types.,is_structured}
+
+    @sa @ref is_primitive() -- returns whether value is primitive
+    @sa @ref is_array() -- returns whether value is an array
+    @sa @ref is_object() -- returns whether value is an object
+
+    @since version 1.0.0
+    */
+    constexpr bool is_structured() const noexcept
+    {
+        return is_array() or is_object();
+    }
+
+    /*!
+    @brief return whether value is null
+
+    This function returns true iff the JSON value is null.
+
+    @return `true` if type is null, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_null()` for all JSON
+    types.,is_null}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_null() const noexcept
+    {
+        return m_type == value_t::null;
+    }
+
+    /*!
+    @brief return whether value is a boolean
+
+    This function returns true iff the JSON value is a boolean.
+
+    @return `true` if type is boolean, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_boolean()` for all JSON
+    types.,is_boolean}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_boolean() const noexcept
+    {
+        return m_type == value_t::boolean;
+    }
+
+    /*!
+    @brief return whether value is a number
+
+    This function returns true iff the JSON value is a number. This includes
+    both integer and floating-point values.
+
+    @return `true` if type is number (regardless whether integer, unsigned
+    integer or floating-type), `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_number()` for all JSON
+    types.,is_number}
+
+    @sa @ref is_number_integer() -- check if value is an integer or unsigned
+    integer number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
+    @sa @ref is_number_float() -- check if value is a floating-point number
+
+    @since version 1.0.0
+    */
+    constexpr bool is_number() const noexcept
+    {
+        return is_number_integer() or is_number_float();
+    }
+
+    /*!
+    @brief return whether value is an integer number
+
+    This function returns true iff the JSON value is an integer or unsigned
+    integer number. This excludes floating-point values.
+
+    @return `true` if type is an integer or unsigned integer number, `false`
+    otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_number_integer()` for all
+    JSON types.,is_number_integer}
+
+    @sa @ref is_number() -- check if value is a number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
+    @sa @ref is_number_float() -- check if value is a floating-point number
+
+    @since version 1.0.0
+    */
+    constexpr bool is_number_integer() const noexcept
+    {
+        return m_type == value_t::number_integer or m_type == value_t::number_unsigned;
+    }
+
+    /*!
+    @brief return whether value is an unsigned integer number
+
+    This function returns true iff the JSON value is an unsigned integer
+    number. This excludes floating-point and (signed) integer values.
+
+    @return `true` if type is an unsigned integer number, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_number_unsigned()` for all
+    JSON types.,is_number_unsigned}
+
+    @sa @ref is_number() -- check if value is a number
+    @sa @ref is_number_integer() -- check if value is an integer or unsigned
+    integer number
+    @sa @ref is_number_float() -- check if value is a floating-point number
+
+    @since version 2.0.0
+    */
+    constexpr bool is_number_unsigned() const noexcept
+    {
+        return m_type == value_t::number_unsigned;
+    }
+
+    /*!
+    @brief return whether value is a floating-point number
+
+    This function returns true iff the JSON value is a floating-point number.
+    This excludes integer and unsigned integer values.
+
+    @return `true` if type is a floating-point number, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_number_float()` for all
+    JSON types.,is_number_float}
+
+    @sa @ref is_number() -- check if value is number
+    @sa @ref is_number_integer() -- check if value is an integer number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
+
+    @since version 1.0.0
+    */
+    constexpr bool is_number_float() const noexcept
+    {
+        return m_type == value_t::number_float;
+    }
+
+    /*!
+    @brief return whether value is an object
+
+    This function returns true iff the JSON value is an object.
+
+    @return `true` if type is object, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_object()` for all JSON
+    types.,is_object}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_object() const noexcept
+    {
+        return m_type == value_t::object;
+    }
+
+    /*!
+    @brief return whether value is an array
+
+    This function returns true iff the JSON value is an array.
+
+    @return `true` if type is array, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_array()` for all JSON
+    types.,is_array}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_array() const noexcept
+    {
+        return m_type == value_t::array;
+    }
+
+    /*!
+    @brief return whether value is a string
+
+    This function returns true iff the JSON value is a string.
+
+    @return `true` if type is string, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_string()` for all JSON
+    types.,is_string}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_string() const noexcept
+    {
+        return m_type == value_t::string;
+    }
+
+    /*!
+    @brief return whether value is discarded
+
+    This function returns true iff the JSON value was discarded during parsing
+    with a callback function (see @ref parser_callback_t).
+
+    @note This function will always be `false` for JSON values after parsing.
+    That is, discarded values can only occur during parsing, but will be
+    removed when inside a structured value or replaced by null in other cases.
+
+    @return `true` if type is discarded, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_discarded()` for all JSON
+    types.,is_discarded}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_discarded() const noexcept
+    {
+        return m_type == value_t::discarded;
+    }
+
+    /*!
+    @brief return the type of the JSON value (implicit)
+
+    Implicitly return the type of the JSON value as a value from the @ref
+    value_t enumeration.
+
+    @return the type of the JSON value
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies the @ref value_t operator for
+    all JSON types.,operator__value_t}
+
+    @since version 1.0.0
+    */
+    constexpr operator value_t() const noexcept
+    {
+        return m_type;
+    }
+
+    /// @}
+
+  private:
+    //////////////////
+    // value access //
+    //////////////////
+
+    /// get an object (explicit)
+    template <class T, typename
+              std::enable_if<
+                  std::is_convertible<typename object_t::key_type, typename T::key_type>::value and
+                  std::is_convertible<basic_json_t, typename T::mapped_type>::value
+                  , int>::type = 0>
+    T get_impl(T*) const
+    {
+        if (is_object())
+        {
+            return T(m_value.object->begin(), m_value.object->end());
+        }
+        else
+        {
+            throw std::domain_error("type must be object, but is " + type_name());
+        }
+    }
+
+    /// get an object (explicit)
+    object_t get_impl(object_t*) const
+    {
+        if (is_object())
+        {
+            return *(m_value.object);
+        }
+        else
+        {
+            throw std::domain_error("type must be object, but is " + type_name());
+        }
+    }
+
+    /// get an array (explicit)
+    template <class T, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, typename T::value_type>::value and
+                  not std::is_same<basic_json_t, typename T::value_type>::value and
+                  not std::is_arithmetic<T>::value and
+                  not std::is_convertible<std::string, T>::value and
+                  not has_mapped_type<T>::value
+                  , int>::type = 0>
+    T get_impl(T*) const
+    {
+        if (is_array())
+        {
+            T to_vector;
+            std::transform(m_value.array->begin(), m_value.array->end(),
+                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
+            {
+                return i.get<typename T::value_type>();
+            });
+            return to_vector;
+        }
+        else
+        {
+            throw std::domain_error("type must be array, but is " + type_name());
+        }
+    }
+
+    /// get an array (explicit)
+    template <class T, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, T>::value and
+                  not std::is_same<basic_json_t, T>::value
+                  , int>::type = 0>
+    std::vector<T> get_impl(std::vector<T>*) const
+    {
+        if (is_array())
+        {
+            std::vector<T> to_vector;
+            to_vector.reserve(m_value.array->size());
+            std::transform(m_value.array->begin(), m_value.array->end(),
+                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
+            {
+                return i.get<T>();
+            });
+            return to_vector;
+        }
+        else
+        {
+            throw std::domain_error("type must be array, but is " + type_name());
+        }
+    }
+
+    /// get an array (explicit)
+    template <class T, typename
+              std::enable_if<
+                  std::is_same<basic_json, typename T::value_type>::value and
+                  not has_mapped_type<T>::value
+                  , int>::type = 0>
+    T get_impl(T*) const
+    {
+        if (is_array())
+        {
+            return T(m_value.array->begin(), m_value.array->end());
+        }
+        else
+        {
+            throw std::domain_error("type must be array, but is " + type_name());
+        }
+    }
+
+    /// get an array (explicit)
+    array_t get_impl(array_t*) const
+    {
+        if (is_array())
+        {
+            return *(m_value.array);
+        }
+        else
+        {
+            throw std::domain_error("type must be array, but is " + type_name());
+        }
+    }
+
+    /// get a string (explicit)
+    template <typename T, typename
+              std::enable_if<
+                  std::is_convertible<string_t, T>::value
+                  , int>::type = 0>
+    T get_impl(T*) const
+    {
+        if (is_string())
+        {
+            return *m_value.string;
+        }
+        else
+        {
+            throw std::domain_error("type must be string, but is " + type_name());
+        }
+    }
+
+    /// get a number (explicit)
+    template<typename T, typename
+             std::enable_if<
+                 std::is_arithmetic<T>::value
+                 , int>::type = 0>
+    T get_impl(T*) const
+    {
+        switch (m_type)
+        {
+            case value_t::number_integer:
+            {
+                return static_cast<T>(m_value.number_integer);
+            }
+
+            case value_t::number_unsigned:
+            {
+                return static_cast<T>(m_value.number_unsigned);
+            }
+
+            case value_t::number_float:
+            {
+                return static_cast<T>(m_value.number_float);
+            }
+
+            default:
+            {
+                throw std::domain_error("type must be number, but is " + type_name());
+            }
+        }
+    }
+
+    /// get a boolean (explicit)
+    constexpr boolean_t get_impl(boolean_t*) const
+    {
+        return is_boolean()
+               ? m_value.boolean
+               : throw std::domain_error("type must be boolean, but is " + type_name());
+    }
+
+    /// get a pointer to the value (object)
+    object_t* get_impl_ptr(object_t*) noexcept
+    {
+        return is_object() ? m_value.object : nullptr;
+    }
+
+    /// get a pointer to the value (object)
+    constexpr const object_t* get_impl_ptr(const object_t*) const noexcept
+    {
+        return is_object() ? m_value.object : nullptr;
+    }
+
+    /// get a pointer to the value (array)
+    array_t* get_impl_ptr(array_t*) noexcept
+    {
+        return is_array() ? m_value.array : nullptr;
+    }
+
+    /// get a pointer to the value (array)
+    constexpr const array_t* get_impl_ptr(const array_t*) const noexcept
+    {
+        return is_array() ? m_value.array : nullptr;
+    }
+
+    /// get a pointer to the value (string)
+    string_t* get_impl_ptr(string_t*) noexcept
+    {
+        return is_string() ? m_value.string : nullptr;
+    }
+
+    /// get a pointer to the value (string)
+    constexpr const string_t* get_impl_ptr(const string_t*) const noexcept
+    {
+        return is_string() ? m_value.string : nullptr;
+    }
+
+    /// get a pointer to the value (boolean)
+    boolean_t* get_impl_ptr(boolean_t*) noexcept
+    {
+        return is_boolean() ? &m_value.boolean : nullptr;
+    }
+
+    /// get a pointer to the value (boolean)
+    constexpr const boolean_t* get_impl_ptr(const boolean_t*) const noexcept
+    {
+        return is_boolean() ? &m_value.boolean : nullptr;
+    }
+
+    /// get a pointer to the value (integer number)
+    number_integer_t* get_impl_ptr(number_integer_t*) noexcept
+    {
+        return is_number_integer() ? &m_value.number_integer : nullptr;
+    }
+
+    /// get a pointer to the value (integer number)
+    constexpr const number_integer_t* get_impl_ptr(const number_integer_t*) const noexcept
+    {
+        return is_number_integer() ? &m_value.number_integer : nullptr;
+    }
+
+    /// get a pointer to the value (unsigned number)
+    number_unsigned_t* get_impl_ptr(number_unsigned_t*) noexcept
+    {
+        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
+    }
+
+    /// get a pointer to the value (unsigned number)
+    constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t*) const noexcept
+    {
+        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
+    }
+
+    /// get a pointer to the value (floating-point number)
+    number_float_t* get_impl_ptr(number_float_t*) noexcept
+    {
+        return is_number_float() ? &m_value.number_float : nullptr;
+    }
+
+    /// get a pointer to the value (floating-point number)
+    constexpr const number_float_t* get_impl_ptr(const number_float_t*) const noexcept
+    {
+        return is_number_float() ? &m_value.number_float : nullptr;
+    }
+
+    /*!
+    @brief helper function to implement get_ref()
+
+    This funcion helps to implement get_ref() without code duplication for
+    const and non-const overloads
+
+    @tparam ThisType will be deduced as `basic_json` or `const basic_json`
+
+    @throw std::domain_error if ReferenceType does not match underlying value
+    type of the current JSON
+    */
+    template<typename ReferenceType, typename ThisType>
+    static ReferenceType get_ref_impl(ThisType& obj)
+    {
+        // helper type
+        using PointerType = typename std::add_pointer<ReferenceType>::type;
+
+        // delegate the call to get_ptr<>()
+        auto ptr = obj.template get_ptr<PointerType>();
+
+        if (ptr != nullptr)
+        {
+            return *ptr;
+        }
+        else
+        {
+            throw std::domain_error("incompatible ReferenceType for get_ref, actual type is " +
+                                    obj.type_name());
+        }
+    }
+
+  public:
+
+    /// @name value access
+    /// Direct access to the stored value of a JSON value.
+    /// @{
+
+    /*!
+    @brief get a value (explicit)
+
+    Explicit type conversion between the JSON value and a compatible value.
+
+    @tparam ValueType non-pointer type compatible to the JSON value, for
+    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
+    `std::vector` types for JSON arrays
+
+    @return copy of the JSON value, converted to type @a ValueType
+
+    @throw std::domain_error in case passed type @a ValueType is incompatible
+    to JSON; example: `"type must be object, but is null"`
+
+    @complexity Linear in the size of the JSON value.
+
+    @liveexample{The example below shows several conversions from JSON values
+    to other types. There a few things to note: (1) Floating-point numbers can
+    be converted to integers\, (2) A JSON array can be converted to a standard
+    `std::vector<short>`\, (3) A JSON object can be converted to C++
+    associative containers such as `std::unordered_map<std::string\,
+    json>`.,get__ValueType_const}
+
+    @internal
+    The idea of using a casted null pointer to choose the correct
+    implementation is from <http://stackoverflow.com/a/8315197/266378>.
+    @endinternal
+
+    @sa @ref operator ValueType() const for implicit conversion
+    @sa @ref get() for pointer-member access
+
+    @since version 1.0.0
+    */
+    template<typename ValueType, typename
+             std::enable_if<
+                 not std::is_pointer<ValueType>::value
+                 , int>::type = 0>
+    ValueType get() const
+    {
+        return get_impl(static_cast<ValueType*>(nullptr));
+    }
+
+    /*!
+    @brief get a pointer value (explicit)
+
+    Explicit pointer access to the internally stored JSON value. No copies are
+    made.
+
+    @warning The pointer becomes invalid if the underlying JSON object
+    changes.
+
+    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
+    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
+    @ref number_unsigned_t, or @ref number_float_t.
+
+    @return pointer to the internally stored JSON value if the requested
+    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how pointers to internal values of a
+    JSON value can be requested. Note that no type conversions are made and a
+    `nullptr` is returned if the value and the requested pointer type does not
+    match.,get__PointerType}
+
+    @sa @ref get_ptr() for explicit pointer-member access
+
+    @since version 1.0.0
+    */
+    template<typename PointerType, typename
+             std::enable_if<
+                 std::is_pointer<PointerType>::value
+                 , int>::type = 0>
+    PointerType get() noexcept
+    {
+        // delegate the call to get_ptr
+        return get_ptr<PointerType>();
+    }
+
+    /*!
+    @brief get a pointer value (explicit)
+    @copydoc get()
+    */
+    template<typename PointerType, typename
+             std::enable_if<
+                 std::is_pointer<PointerType>::value
+                 , int>::type = 0>
+    constexpr const PointerType get() const noexcept
+    {
+        // delegate the call to get_ptr
+        return get_ptr<PointerType>();
+    }
+
+    /*!
+    @brief get a pointer value (implicit)
+
+    Implicit pointer access to the internally stored JSON value. No copies are
+    made.
+
+    @warning Writing data to the pointee of the result yields an undefined
+    state.
+
+    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
+    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
+    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
+    assertion.
+
+    @return pointer to the internally stored JSON value if the requested
+    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how pointers to internal values of a
+    JSON value can be requested. Note that no type conversions are made and a
+    `nullptr` is returned if the value and the requested pointer type does not
+    match.,get_ptr}
+
+    @since version 1.0.0
+    */
+    template<typename PointerType, typename
+             std::enable_if<
+                 std::is_pointer<PointerType>::value
+                 , int>::type = 0>
+    PointerType get_ptr() noexcept
+    {
+        // get the type of the PointerType (remove pointer and const)
+        using pointee_t = typename std::remove_const<typename
+                          std::remove_pointer<typename
+                          std::remove_const<PointerType>::type>::type>::type;
+        // make sure the type matches the allowed types
+        static_assert(
+            std::is_same<object_t, pointee_t>::value
+            or std::is_same<array_t, pointee_t>::value
+            or std::is_same<string_t, pointee_t>::value
+            or std::is_same<boolean_t, pointee_t>::value
+            or std::is_same<number_integer_t, pointee_t>::value
+            or std::is_same<number_unsigned_t, pointee_t>::value
+            or std::is_same<number_float_t, pointee_t>::value
+            , "incompatible pointer type");
+
+        // delegate the call to get_impl_ptr<>()
+        return get_impl_ptr(static_cast<PointerType>(nullptr));
+    }
+
+    /*!
+    @brief get a pointer value (implicit)
+    @copydoc get_ptr()
+    */
+    template<typename PointerType, typename
+             std::enable_if<
+                 std::is_pointer<PointerType>::value
+                 and std::is_const<typename std::remove_pointer<PointerType>::type>::value
+                 , int>::type = 0>
+    constexpr const PointerType get_ptr() const noexcept
+    {
+        // get the type of the PointerType (remove pointer and const)
+        using pointee_t = typename std::remove_const<typename
+                          std::remove_pointer<typename
+                          std::remove_const<PointerType>::type>::type>::type;
+        // make sure the type matches the allowed types
+        static_assert(
+            std::is_same<object_t, pointee_t>::value
+            or std::is_same<array_t, pointee_t>::value
+            or std::is_same<string_t, pointee_t>::value
+            or std::is_same<boolean_t, pointee_t>::value
+            or std::is_same<number_integer_t, pointee_t>::value
+            or std::is_same<number_unsigned_t, pointee_t>::value
+            or std::is_same<number_float_t, pointee_t>::value
+            , "incompatible pointer type");
+
+        // delegate the call to get_impl_ptr<>() const
+        return get_impl_ptr(static_cast<const PointerType>(nullptr));
+    }
+
+    /*!
+    @brief get a reference value (implicit)
+
+    Implict reference access to the internally stored JSON value. No copies
+    are made.
+
+    @warning Writing data to the referee of the result yields an undefined
+    state.
+
+    @tparam ReferenceType reference type; must be a reference to @ref array_t,
+    @ref object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, or
+    @ref number_float_t. Enforced by static assertion.
+
+    @return reference to the internally stored JSON value if the requested
+    reference type @a ReferenceType fits to the JSON value; throws
+    std::domain_error otherwise
+
+    @throw std::domain_error in case passed type @a ReferenceType is
+    incompatible with the stored JSON value
+
+    @complexity Constant.
+
+    @liveexample{The example shows several calls to `get_ref()`.,get_ref}
+
+    @since version 1.1.0
+    */
+    template<typename ReferenceType, typename
+             std::enable_if<
+                 std::is_reference<ReferenceType>::value
+                 , int>::type = 0>
+    ReferenceType get_ref()
+    {
+        // delegate call to get_ref_impl
+        return get_ref_impl<ReferenceType>(*this);
+    }
+
+    /*!
+    @brief get a reference value (implicit)
+    @copydoc get_ref()
+    */
+    template<typename ReferenceType, typename
+             std::enable_if<
+                 std::is_reference<ReferenceType>::value
+                 and std::is_const<typename std::remove_reference<ReferenceType>::type>::value
+                 , int>::type = 0>
+    ReferenceType get_ref() const
+    {
+        // delegate call to get_ref_impl
+        return get_ref_impl<ReferenceType>(*this);
+    }
+
+    /*!
+    @brief get a value (implicit)
+
+    Implicit type conversion between the JSON value and a compatible value.
+    The call is realized by calling @ref get() const.
+
+    @tparam ValueType non-pointer type compatible to the JSON value, for
+    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
+    `std::vector` types for JSON arrays. The character type of @ref string_t
+    as well as an initializer list of this type is excluded to avoid
+    ambiguities as these types implicitly convert to `std::string`.
+
+    @return copy of the JSON value, converted to type @a ValueType
+
+    @throw std::domain_error in case passed type @a ValueType is incompatible
+    to JSON, thrown by @ref get() const
+
+    @complexity Linear in the size of the JSON value.
+
+    @liveexample{The example below shows several conversions from JSON values
+    to other types. There a few things to note: (1) Floating-point numbers can
+    be converted to integers\, (2) A JSON array can be converted to a standard
+    `std::vector<short>`\, (3) A JSON object can be converted to C++
+    associative containers such as `std::unordered_map<std::string\,
+    json>`.,operator__ValueType}
+
+    @since version 1.0.0
+    */
+    template < typename ValueType, typename
+               std::enable_if <
+                   not std::is_pointer<ValueType>::value
+                   and not std::is_same<ValueType, typename string_t::value_type>::value
+#ifndef _MSC_VER  // Fix for issue #167 operator<< abiguity under VS2015
+                   and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
+#endif
+                   , int >::type = 0 >
+    operator ValueType() const
+    {
+        // delegate the call to get<>() const
+        return get<ValueType>();
+    }
+
+    /// @}
+
+
+    ////////////////////
+    // element access //
+    ////////////////////
+
+    /// @name element access
+    /// Access to the JSON value.
+    /// @{
+
+    /*!
+    @brief access specified array element with bounds checking
+
+    Returns a reference to the element at specified location @a idx, with
+    bounds checking.
+
+    @param[in] idx  index of the element to access
+
+    @return reference to the element at index @a idx
+
+    @throw std::domain_error if the JSON value is not an array; example:
+    `"cannot use at() with string"`
+    @throw std::out_of_range if the index @a idx is out of range of the array;
+    that is, `idx >= size()`; example: `"array index 7 is out of range"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how array elements can be read and
+    written using `at()`.,at__size_type}
+
+    @since version 1.0.0
+    */
+    reference at(size_type idx)
+    {
+        // at only works for arrays
+        if (is_array())
+        {
+            try
+            {
+                return m_value.array->at(idx);
+            }
+            catch (std::out_of_range&)
+            {
+                // create better exception explanation
+                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use at() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified array element with bounds checking
+
+    Returns a const reference to the element at specified location @a idx,
+    with bounds checking.
+
+    @param[in] idx  index of the element to access
+
+    @return const reference to the element at index @a idx
+
+    @throw std::domain_error if the JSON value is not an array; example:
+    `"cannot use at() with string"`
+    @throw std::out_of_range if the index @a idx is out of range of the array;
+    that is, `idx >= size()`; example: `"array index 7 is out of range"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how array elements can be read using
+    `at()`.,at__size_type_const}
+
+    @since version 1.0.0
+    */
+    const_reference at(size_type idx) const
+    {
+        // at only works for arrays
+        if (is_array())
+        {
+            try
+            {
+                return m_value.array->at(idx);
+            }
+            catch (std::out_of_range&)
+            {
+                // create better exception explanation
+                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use at() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element with bounds checking
+
+    Returns a reference to the element at with specified key @a key, with
+    bounds checking.
+
+    @param[in] key  key of the element to access
+
+    @return reference to the element at key @a key
+
+    @throw std::domain_error if the JSON value is not an object; example:
+    `"cannot use at() with boolean"`
+    @throw std::out_of_range if the key @a key is is not stored in the object;
+    that is, `find(key) == end()`; example: `"key "the fast" not found"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using `at()`.,at__object_t_key_type}
+
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    reference at(const typename object_t::key_type& key)
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            try
+            {
+                return m_value.object->at(key);
+            }
+            catch (std::out_of_range&)
+            {
+                // create better exception explanation
+                throw std::out_of_range("key '" + key + "' not found");
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use at() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element with bounds checking
+
+    Returns a const reference to the element at with specified key @a key,
+    with bounds checking.
+
+    @param[in] key  key of the element to access
+
+    @return const reference to the element at key @a key
+
+    @throw std::domain_error if the JSON value is not an object; example:
+    `"cannot use at() with boolean"`
+    @throw std::out_of_range if the key @a key is is not stored in the object;
+    that is, `find(key) == end()`; example: `"key "the fast" not found"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    `at()`.,at__object_t_key_type_const}
+
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    const_reference at(const typename object_t::key_type& key) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            try
+            {
+                return m_value.object->at(key);
+            }
+            catch (std::out_of_range&)
+            {
+                // create better exception explanation
+                throw std::out_of_range("key '" + key + "' not found");
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use at() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified array element
+
+    Returns a reference to the element at specified location @a idx.
+
+    @note If @a idx is beyond the range of the array (i.e., `idx >= size()`),
+    then the array is silently filled up with `null` values to make `idx` a
+    valid reference to the last stored element.
+
+    @param[in] idx  index of the element to access
+
+    @return reference to the element at index @a idx
+
+    @throw std::domain_error if JSON is not an array or null; example:
+    `"cannot use operator[] with string"`
+
+    @complexity Constant if @a idx is in the range of the array. Otherwise
+    linear in `idx - size()`.
+
+    @liveexample{The example below shows how array elements can be read and
+    written using `[]` operator. Note the addition of `null`
+    values.,operatorarray__size_type}
+
+    @since version 1.0.0
+    */
+    reference operator[](size_type idx)
+    {
+        // implicitly convert null value to an empty array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value.array = create<array_t>();
+            assert_invariant();
+        }
+
+        // operator[] only works for arrays
+        if (is_array())
+        {
+            // fill up array with null values if given idx is outside range
+            if (idx >= m_value.array->size())
+            {
+                m_value.array->insert(m_value.array->end(),
+                                      idx - m_value.array->size() + 1,
+                                      basic_json());
+            }
+
+            return m_value.array->operator[](idx);
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified array element
+
+    Returns a const reference to the element at specified location @a idx.
+
+    @param[in] idx  index of the element to access
+
+    @return const reference to the element at index @a idx
+
+    @throw std::domain_error if JSON is not an array; example: `"cannot use
+    operator[] with null"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how array elements can be read using
+    the `[]` operator.,operatorarray__size_type_const}
+
+    @since version 1.0.0
+    */
+    const_reference operator[](size_type idx) const
+    {
+        // const operator[] only works for arrays
+        if (is_array())
+        {
+            return m_value.array->operator[](idx);
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element
+
+    Returns a reference to the element at with specified key @a key.
+
+    @note If @a key is not found in the object, then it is silently added to
+    the object and filled with a `null` value to make `key` a valid reference.
+    In case the value was `null` before, it is converted to an object.
+
+    @param[in] key  key of the element to access
+
+    @return reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object or null; example:
+    `"cannot use operator[] with string"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using the `[]` operator.,operatorarray__key_type}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    reference operator[](const typename object_t::key_type& key)
+    {
+        // implicitly convert null value to an empty object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value.object = create<object_t>();
+            assert_invariant();
+        }
+
+        // operator[] only works for objects
+        if (is_object())
+        {
+            return m_value.object->operator[](key);
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief read-only access specified object element
+
+    Returns a const reference to the element at with specified key @a key. No
+    bounds checking is performed.
+
+    @warning If the element with key @a key does not exist, the behavior is
+    undefined.
+
+    @param[in] key  key of the element to access
+
+    @return const reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    operator[] with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    the `[]` operator.,operatorarray__key_type_const}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    const_reference operator[](const typename object_t::key_type& key) const
+    {
+        // const operator[] only works for objects
+        if (is_object())
+        {
+            assert(m_value.object->find(key) != m_value.object->end());
+            return m_value.object->find(key)->second;
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element
+
+    Returns a reference to the element at with specified key @a key.
+
+    @note If @a key is not found in the object, then it is silently added to
+    the object and filled with a `null` value to make `key` a valid reference.
+    In case the value was `null` before, it is converted to an object.
+
+    @param[in] key  key of the element to access
+
+    @return reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object or null; example:
+    `"cannot use operator[] with string"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using the `[]` operator.,operatorarray__key_type}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    template<typename T, std::size_t n>
+    reference operator[](T * (&key)[n])
+    {
+        return operator[](static_cast<const T>(key));
+    }
+
+    /*!
+    @brief read-only access specified object element
+
+    Returns a const reference to the element at with specified key @a key. No
+    bounds checking is performed.
+
+    @warning If the element with key @a key does not exist, the behavior is
+    undefined.
+
+    @note This function is required for compatibility reasons with Clang.
+
+    @param[in] key  key of the element to access
+
+    @return const reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    operator[] with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    the `[]` operator.,operatorarray__key_type_const}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    template<typename T, std::size_t n>
+    const_reference operator[](T * (&key)[n]) const
+    {
+        return operator[](static_cast<const T>(key));
+    }
+
+    /*!
+    @brief access specified object element
+
+    Returns a reference to the element at with specified key @a key.
+
+    @note If @a key is not found in the object, then it is silently added to
+    the object and filled with a `null` value to make `key` a valid reference.
+    In case the value was `null` before, it is converted to an object.
+
+    @param[in] key  key of the element to access
+
+    @return reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object or null; example:
+    `"cannot use operator[] with string"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using the `[]` operator.,operatorarray__key_type}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.1.0
+    */
+    template<typename T>
+    reference operator[](T* key)
+    {
+        // implicitly convert null to object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value = value_t::object;
+            assert_invariant();
+        }
+
+        // at only works for objects
+        if (is_object())
+        {
+            return m_value.object->operator[](key);
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief read-only access specified object element
+
+    Returns a const reference to the element at with specified key @a key. No
+    bounds checking is performed.
+
+    @warning If the element with key @a key does not exist, the behavior is
+    undefined.
+
+    @param[in] key  key of the element to access
+
+    @return const reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    operator[] with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    the `[]` operator.,operatorarray__key_type_const}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.1.0
+    */
+    template<typename T>
+    const_reference operator[](T* key) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            assert(m_value.object->find(key) != m_value.object->end());
+            return m_value.object->find(key)->second;
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element with default value
+
+    Returns either a copy of an object's element at the specified key @a key
+    or a given default value if no element with key @a key exists.
+
+    The function is basically equivalent to executing
+    @code {.cpp}
+    try {
+        return at(key);
+    } catch(std::out_of_range) {
+        return default_value;
+    }
+    @endcode
+
+    @note Unlike @ref at(const typename object_t::key_type&), this function
+    does not throw if the given key @a key was not found.
+
+    @note Unlike @ref operator[](const typename object_t::key_type& key), this
+    function does not implicitly add an element to the position defined by @a
+    key. This function is furthermore also applicable to const objects.
+
+    @param[in] key  key of the element to access
+    @param[in] default_value  the value to return if @a key is not found
+
+    @tparam ValueType type compatible to JSON values, for instance `int` for
+    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
+    JSON arrays. Note the type of the expected value at @a key and the default
+    value @a default_value must be compatible.
+
+    @return copy of the element at key @a key or @a default_value if @a key
+    is not found
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    value() with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be queried
+    with a default value.,basic_json__value}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
+
+    @since version 1.0.0
+    */
+    template <class ValueType, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, ValueType>::value
+                  , int>::type = 0>
+    ValueType value(const typename object_t::key_type& key, ValueType default_value) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            // if key is found, return value and given default value otherwise
+            const auto it = find(key);
+            if (it != end())
+            {
+                return *it;
+            }
+            else
+            {
+                return default_value;
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use value() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief overload for a default value of type const char*
+    @copydoc basic_json::value(const typename object_t::key_type&, ValueType) const
+    */
+    string_t value(const typename object_t::key_type& key, const char* default_value) const
+    {
+        return value(key, string_t(default_value));
+    }
+
+    /*!
+    @brief access specified object element via JSON Pointer with default value
+
+    Returns either a copy of an object's element at the specified key @a key
+    or a given default value if no element with key @a key exists.
+
+    The function is basically equivalent to executing
+    @code {.cpp}
+    try {
+        return at(ptr);
+    } catch(std::out_of_range) {
+        return default_value;
+    }
+    @endcode
+
+    @note Unlike @ref at(const json_pointer&), this function does not throw
+    if the given key @a key was not found.
+
+    @param[in] ptr  a JSON pointer to the element to access
+    @param[in] default_value  the value to return if @a ptr found no value
+
+    @tparam ValueType type compatible to JSON values, for instance `int` for
+    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
+    JSON arrays. Note the type of the expected value at @a key and the default
+    value @a default_value must be compatible.
+
+    @return copy of the element at key @a key or @a default_value if @a key
+    is not found
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    value() with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be queried
+    with a default value.,basic_json__value_ptr}
+
+    @sa @ref operator[](const json_pointer&) for unchecked access by reference
+
+    @since version 2.0.2
+    */
+    template <class ValueType, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, ValueType>::value
+                  , int>::type = 0>
+    ValueType value(const json_pointer& ptr, ValueType default_value) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            // if pointer resolves a value, return it or use default value
+            try
+            {
+                return ptr.get_checked(this);
+            }
+            catch (std::out_of_range&)
+            {
+                return default_value;
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use value() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief overload for a default value of type const char*
+    @copydoc basic_json::value(const json_pointer&, ValueType) const
+    */
+    string_t value(const json_pointer& ptr, const char* default_value) const
+    {
+        return value(ptr, string_t(default_value));
+    }
+
+    /*!
+    @brief access the first element
+
+    Returns a reference to the first element in the container. For a JSON
+    container `c`, the expression `c.front()` is equivalent to `*c.begin()`.
+
+    @return In case of a structured type (array or object), a reference to the
+    first element is returned. In cast of number, string, or boolean values, a
+    reference to the value is returned.
+
+    @complexity Constant.
+
+    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
+    or an empty array or object (undefined behavior, guarded by assertions).
+    @post The JSON value remains unchanged.
+
+    @throw std::out_of_range when called on `null` value
+
+    @liveexample{The following code shows an example for `front()`.,front}
+
+    @sa @ref back() -- access the last element
+
+    @since version 1.0.0
+    */
+    reference front()
+    {
+        return *begin();
+    }
+
+    /*!
+    @copydoc basic_json::front()
+    */
+    const_reference front() const
+    {
+        return *cbegin();
+    }
+
+    /*!
+    @brief access the last element
+
+    Returns a reference to the last element in the container. For a JSON
+    container `c`, the expression `c.back()` is equivalent to
+    @code {.cpp}
+    auto tmp = c.end();
+    --tmp;
+    return *tmp;
+    @endcode
+
+    @return In case of a structured type (array or object), a reference to the
+    last element is returned. In cast of number, string, or boolean values, a
+    reference to the value is returned.
+
+    @complexity Constant.
+
+    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
+    or an empty array or object (undefined behavior, guarded by assertions).
+    @post The JSON value remains unchanged.
+
+    @throw std::out_of_range when called on `null` value.
+
+    @liveexample{The following code shows an example for `back()`.,back}
+
+    @sa @ref front() -- access the first element
+
+    @since version 1.0.0
+    */
+    reference back()
+    {
+        auto tmp = end();
+        --tmp;
+        return *tmp;
+    }
+
+    /*!
+    @copydoc basic_json::back()
+    */
+    const_reference back() const
+    {
+        auto tmp = cend();
+        --tmp;
+        return *tmp;
+    }
+
+    /*!
+    @brief remove element given an iterator
+
+    Removes the element specified by iterator @a pos. The iterator @a pos must
+    be valid and dereferenceable. Thus the `end()` iterator (which is valid,
+    but is not dereferenceable) cannot be used as a value for @a pos.
+
+    If called on a primitive type other than `null`, the resulting JSON value
+    will be `null`.
+
+    @param[in] pos iterator to the element to remove
+    @return Iterator following the last removed element. If the iterator @a
+    pos refers to the last element, the `end()` iterator is returned.
+
+    @tparam InteratorType an @ref iterator or @ref const_iterator
+
+    @post Invalidates iterators and references at or after the point of the
+    erase, including the `end()` iterator.
+
+    @throw std::domain_error if called on a `null` value; example: `"cannot
+    use erase() with null"`
+    @throw std::domain_error if called on an iterator which does not belong to
+    the current JSON value; example: `"iterator does not fit current value"`
+    @throw std::out_of_range if called on a primitive type with invalid
+    iterator (i.e., any iterator which is not `begin()`); example: `"iterator
+    out of range"`
+
+    @complexity The complexity depends on the type:
+    - objects: amortized constant
+    - arrays: linear in distance between pos and the end of the container
+    - strings: linear in the length of the string
+    - other types: constant
+
+    @liveexample{The example shows the result of `erase()` for different JSON
+    types.,erase__IteratorType}
+
+    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
+
+    @since version 1.0.0
+    */
+    template <class InteratorType, typename
+              std::enable_if<
+                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
+                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
+                  , int>::type
+              = 0>
+    InteratorType erase(InteratorType pos)
+    {
+        // make sure iterator fits the current value
+        if (this != pos.m_object)
+        {
+            throw std::domain_error("iterator does not fit current value");
+        }
+
+        InteratorType result = end();
+
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
+            {
+                if (not pos.m_it.primitive_iterator.is_begin())
+                {
+                    throw std::out_of_range("iterator out of range");
+                }
+
+                if (is_string())
+                {
+                    AllocatorType<string_t> alloc;
+                    alloc.destroy(m_value.string);
+                    alloc.deallocate(m_value.string, 1);
+                    m_value.string = nullptr;
+                }
+
+                m_type = value_t::null;
+                assert_invariant();
+                break;
+            }
+
+            case value_t::object:
+            {
+                result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator);
+                break;
+            }
+
+            case value_t::array:
+            {
+                result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator);
+                break;
+            }
+
+            default:
+            {
+                throw std::domain_error("cannot use erase() with " + type_name());
+            }
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief remove elements given an iterator range
+
+    Removes the element specified by the range `[first; last)`. The iterator
+    @a first does not need to be dereferenceable if `first == last`: erasing
+    an empty range is a no-op.
+
+    If called on a primitive type other than `null`, the resulting JSON value
+    will be `null`.
+
+    @param[in] first iterator to the beginning of the range to remove
+    @param[in] last iterator past the end of the range to remove
+    @return Iterator following the last removed element. If the iterator @a
+    second refers to the last element, the `end()` iterator is returned.
+
+    @tparam InteratorType an @ref iterator or @ref const_iterator
+
+    @post Invalidates iterators and references at or after the point of the
+    erase, including the `end()` iterator.
+
+    @throw std::domain_error if called on a `null` value; example: `"cannot
+    use erase() with null"`
+    @throw std::domain_error if called on iterators which does not belong to
+    the current JSON value; example: `"iterators do not fit current value"`
+    @throw std::out_of_range if called on a primitive type with invalid
+    iterators (i.e., if `first != begin()` and `last != end()`); example:
+    `"iterators out of range"`
+
+    @complexity The complexity depends on the type:
+    - objects: `log(size()) + std::distance(first, last)`
+    - arrays: linear in the distance between @a first and @a last, plus linear
+      in the distance between @a last and end of the container
+    - strings: linear in the length of the string
+    - other types: constant
+
+    @liveexample{The example shows the result of `erase()` for different JSON
+    types.,erase__IteratorType_IteratorType}
+
+    @sa @ref erase(InteratorType) -- removes the element at a given position
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
+
+    @since version 1.0.0
+    */
+    template <class InteratorType, typename
+              std::enable_if<
+                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
+                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
+                  , int>::type
+              = 0>
+    InteratorType erase(InteratorType first, InteratorType last)
+    {
+        // make sure iterator fits the current value
+        if (this != first.m_object or this != last.m_object)
+        {
+            throw std::domain_error("iterators do not fit current value");
+        }
+
+        InteratorType result = end();
+
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
+            {
+                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
+                {
+                    throw std::out_of_range("iterators out of range");
+                }
+
+                if (is_string())
+                {
+                    AllocatorType<string_t> alloc;
+                    alloc.destroy(m_value.string);
+                    alloc.deallocate(m_value.string, 1);
+                    m_value.string = nullptr;
+                }
+
+                m_type = value_t::null;
+                assert_invariant();
+                break;
+            }
+
+            case value_t::object:
+            {
+                result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator,
+                                              last.m_it.object_iterator);
+                break;
+            }
+
+            case value_t::array:
+            {
+                result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator,
+                                             last.m_it.array_iterator);
+                break;
+            }
+
+            default:
+            {
+                throw std::domain_error("cannot use erase() with " + type_name());
+            }
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief remove element from a JSON object given a key
+
+    Removes elements from a JSON object with the key value @a key.
+
+    @param[in] key value of the elements to remove
+
+    @return Number of elements removed. If @a ObjectType is the default
+    `std::map` type, the return value will always be `0` (@a key was not
+    found) or `1` (@a key was found).
+
+    @post References and iterators to the erased elements are invalidated.
+    Other references and iterators are not affected.
+
+    @throw std::domain_error when called on a type other than JSON object;
+    example: `"cannot use erase() with null"`
+
+    @complexity `log(size()) + count(key)`
+
+    @liveexample{The example shows the effect of `erase()`.,erase__key_type}
+
+    @sa @ref erase(InteratorType) -- removes the element at a given position
+    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
+
+    @since version 1.0.0
+    */
+    size_type erase(const typename object_t::key_type& key)
+    {
+        // this erase only works for objects
+        if (is_object())
+        {
+            return m_value.object->erase(key);
+        }
+        else
+        {
+            throw std::domain_error("cannot use erase() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief remove element from a JSON array given an index
+
+    Removes element from a JSON array at the index @a idx.
+
+    @param[in] idx index of the element to remove
+
+    @throw std::domain_error when called on a type other than JSON array;
+    example: `"cannot use erase() with null"`
+    @throw std::out_of_range when `idx >= size()`; example: `"array index 17
+    is out of range"`
+
+    @complexity Linear in distance between @a idx and the end of the container.
+
+    @liveexample{The example shows the effect of `erase()`.,erase__size_type}
+
+    @sa @ref erase(InteratorType) -- removes the element at a given position
+    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+
+    @since version 1.0.0
+    */
+    void erase(const size_type idx)
+    {
+        // this erase only works for arrays
+        if (is_array())
+        {
+            if (idx >= size())
+            {
+                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+            }
+
+            m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
+        }
+        else
+        {
+            throw std::domain_error("cannot use erase() with " + type_name());
+        }
+    }
+
+    /// @}
+
+
+    ////////////
+    // lookup //
+    ////////////
+
+    /// @name lookup
+    /// @{
+
+    /*!
+    @brief find an element in a JSON object
+
+    Finds an element in a JSON object with key equivalent to @a key. If the
+    element is not found or the JSON value is not an object, end() is
+    returned.
+
+    @param[in] key key value of the element to search for
+
+    @return Iterator to an element with key equivalent to @a key. If no such
+    element is found, past-the-end (see end()) iterator is returned.
+
+    @complexity Logarithmic in the size of the JSON object.
+
+    @liveexample{The example shows how `find()` is used.,find__key_type}
+
+    @since version 1.0.0
+    */
+    iterator find(typename object_t::key_type key)
+    {
+        auto result = end();
+
+        if (is_object())
+        {
+            result.m_it.object_iterator = m_value.object->find(key);
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief find an element in a JSON object
+    @copydoc find(typename object_t::key_type)
+    */
+    const_iterator find(typename object_t::key_type key) const
+    {
+        auto result = cend();
+
+        if (is_object())
+        {
+            result.m_it.object_iterator = m_value.object->find(key);
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief returns the number of occurrences of a key in a JSON object
+
+    Returns the number of elements with key @a key. If ObjectType is the
+    default `std::map` type, the return value will always be `0` (@a key was
+    not found) or `1` (@a key was found).
+
+    @param[in] key key value of the element to count
+
+    @return Number of elements with key @a key. If the JSON value is not an
+    object, the return value will be `0`.
+
+    @complexity Logarithmic in the size of the JSON object.
+
+    @liveexample{The example shows how `count()` is used.,count}
+
+    @since version 1.0.0
+    */
+    size_type count(typename object_t::key_type key) const
+    {
+        // return 0 for all nonobject types
+        return is_object() ? m_value.object->count(key) : 0;
+    }
+
+    /// @}
+
+
+    ///////////////
+    // iterators //
+    ///////////////
+
+    /// @name iterators
+    /// @{
+
+    /*!
+    @brief returns an iterator to the first element
+
+    Returns an iterator to the first element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return iterator to the first element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+
+    @liveexample{The following code shows an example for `begin()`.,begin}
+
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref cend() -- returns a const iterator to the end
+
+    @since version 1.0.0
+    */
+    iterator begin() noexcept
+    {
+        iterator result(this);
+        result.set_begin();
+        return result;
+    }
+
+    /*!
+    @copydoc basic_json::cbegin()
+    */
+    const_iterator begin() const noexcept
+    {
+        return cbegin();
+    }
+
+    /*!
+    @brief returns a const iterator to the first element
+
+    Returns a const iterator to the first element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return const iterator to the first element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).begin()`.
+
+    @liveexample{The following code shows an example for `cbegin()`.,cbegin}
+
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref cend() -- returns a const iterator to the end
+
+    @since version 1.0.0
+    */
+    const_iterator cbegin() const noexcept
+    {
+        const_iterator result(this);
+        result.set_begin();
+        return result;
+    }
+
+    /*!
+    @brief returns an iterator to one past the last element
+
+    Returns an iterator to one past the last element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return iterator one past the last element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+
+    @liveexample{The following code shows an example for `end()`.,end}
+
+    @sa @ref cend() -- returns a const iterator to the end
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+
+    @since version 1.0.0
+    */
+    iterator end() noexcept
+    {
+        iterator result(this);
+        result.set_end();
+        return result;
+    }
+
+    /*!
+    @copydoc basic_json::cend()
+    */
+    const_iterator end() const noexcept
+    {
+        return cend();
+    }
+
+    /*!
+    @brief returns a const iterator to one past the last element
+
+    Returns a const iterator to one past the last element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return const iterator one past the last element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).end()`.
+
+    @liveexample{The following code shows an example for `cend()`.,cend}
+
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+
+    @since version 1.0.0
+    */
+    const_iterator cend() const noexcept
+    {
+        const_iterator result(this);
+        result.set_end();
+        return result;
+    }
+
+    /*!
+    @brief returns an iterator to the reverse-beginning
+
+    Returns an iterator to the reverse-beginning; that is, the last element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `reverse_iterator(end())`.
+
+    @liveexample{The following code shows an example for `rbegin()`.,rbegin}
+
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref crend() -- returns a const reverse iterator to the end
+
+    @since version 1.0.0
+    */
+    reverse_iterator rbegin() noexcept
+    {
+        return reverse_iterator(end());
+    }
+
+    /*!
+    @copydoc basic_json::crbegin()
+    */
+    const_reverse_iterator rbegin() const noexcept
+    {
+        return crbegin();
+    }
+
+    /*!
+    @brief returns an iterator to the reverse-end
+
+    Returns an iterator to the reverse-end; that is, one before the first
+    element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `reverse_iterator(begin())`.
+
+    @liveexample{The following code shows an example for `rend()`.,rend}
+
+    @sa @ref crend() -- returns a const reverse iterator to the end
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+
+    @since version 1.0.0
+    */
+    reverse_iterator rend() noexcept
+    {
+        return reverse_iterator(begin());
+    }
+
+    /*!
+    @copydoc basic_json::crend()
+    */
+    const_reverse_iterator rend() const noexcept
+    {
+        return crend();
+    }
+
+    /*!
+    @brief returns a const reverse iterator to the last element
+
+    Returns a const iterator to the reverse-beginning; that is, the last
+    element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).rbegin()`.
+
+    @liveexample{The following code shows an example for `crbegin()`.,crbegin}
+
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref crend() -- returns a const reverse iterator to the end
+
+    @since version 1.0.0
+    */
+    const_reverse_iterator crbegin() const noexcept
+    {
+        return const_reverse_iterator(cend());
+    }
+
+    /*!
+    @brief returns a const reverse iterator to one before the first
+
+    Returns a const reverse iterator to the reverse-end; that is, one before
+    the first element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).rend()`.
+
+    @liveexample{The following code shows an example for `crend()`.,crend}
+
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+
+    @since version 1.0.0
+    */
+    const_reverse_iterator crend() const noexcept
+    {
+        return const_reverse_iterator(cbegin());
+    }
+
+  private:
+    // forward declaration
+    template<typename IteratorType> class iteration_proxy;
+
+  public:
+    /*!
+    @brief wrapper to access iterator member functions in range-based for
+
+    This function allows to access @ref iterator::key() and @ref
+    iterator::value() during range-based for loops. In these loops, a
+    reference to the JSON values is returned, so there is no access to the
+    underlying iterator.
+
+    @note The name of this function is not yet final and may change in the
+    future.
+    */
+    static iteration_proxy<iterator> iterator_wrapper(reference cont)
+    {
+        return iteration_proxy<iterator>(cont);
+    }
+
+    /*!
+    @copydoc iterator_wrapper(reference)
+    */
+    static iteration_proxy<const_iterator> iterator_wrapper(const_reference cont)
+    {
+        return iteration_proxy<const_iterator>(cont);
+    }
+
+    /// @}
+
+
+    //////////////
+    // capacity //
+    //////////////
+
+    /// @name capacity
+    /// @{
+
+    /*!
+    @brief checks whether the container is empty
+
+    Checks if a JSON value has no elements.
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `true`
+            boolean     | `false`
+            string      | `false`
+            number      | `false`
+            object      | result of function `object_t::empty()`
+            array       | result of function `array_t::empty()`
+
+    @note This function does not return whether a string stored as JSON value
+    is empty - it returns whether the JSON container itself is empty which is
+    false in the case of a string.
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their `empty()` functions have constant
+    complexity.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `begin() == end()`.
+
+    @liveexample{The following code uses `empty()` to check if a JSON
+    object contains any elements.,empty}
+
+    @sa @ref size() -- returns the number of elements
+
+    @since version 1.0.0
+    */
+    bool empty() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+            {
+                // null values are empty
+                return true;
+            }
+
+            case value_t::array:
+            {
+                // delegate call to array_t::empty()
+                return m_value.array->empty();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::empty()
+                return m_value.object->empty();
+            }
+
+            default:
+            {
+                // all other types are nonempty
+                return false;
+            }
+        }
+    }
+
+    /*!
+    @brief returns the number of elements
+
+    Returns the number of elements in a JSON value.
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `0`
+            boolean     | `1`
+            string      | `1`
+            number      | `1`
+            object      | result of function object_t::size()
+            array       | result of function array_t::size()
+
+    @note This function does not return the length of a string stored as JSON
+    value - it returns the number of elements in the JSON value which is 1 in
+    the case of a string.
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their size() functions have constant
+    complexity.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `std::distance(begin(), end())`.
+
+    @liveexample{The following code calls `size()` on the different value
+    types.,size}
+
+    @sa @ref empty() -- checks whether the container is empty
+    @sa @ref max_size() -- returns the maximal number of elements
+
+    @since version 1.0.0
+    */
+    size_type size() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+            {
+                // null values are empty
+                return 0;
+            }
+
+            case value_t::array:
+            {
+                // delegate call to array_t::size()
+                return m_value.array->size();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::size()
+                return m_value.object->size();
+            }
+
+            default:
+            {
+                // all other types have size 1
+                return 1;
+            }
+        }
+    }
+
+    /*!
+    @brief returns the maximum possible number of elements
+
+    Returns the maximum number of elements a JSON value is able to hold due to
+    system or library implementation limitations, i.e. `std::distance(begin(),
+    end())` for the JSON value.
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `0` (same as `size()`)
+            boolean     | `1` (same as `size()`)
+            string      | `1` (same as `size()`)
+            number      | `1` (same as `size()`)
+            object      | result of function `object_t::max_size()`
+            array       | result of function `array_t::max_size()`
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their `max_size()` functions have constant
+    complexity.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of returning `b.size()` where `b` is the largest
+      possible JSON value.
+
+    @liveexample{The following code calls `max_size()` on the different value
+    types. Note the output is implementation specific.,max_size}
+
+    @sa @ref size() -- returns the number of elements
+
+    @since version 1.0.0
+    */
+    size_type max_size() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::array:
+            {
+                // delegate call to array_t::max_size()
+                return m_value.array->max_size();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::max_size()
+                return m_value.object->max_size();
+            }
+
+            default:
+            {
+                // all other types have max_size() == size()
+                return size();
+            }
+        }
+    }
+
+    /// @}
+
+
+    ///////////////
+    // modifiers //
+    ///////////////
+
+    /// @name modifiers
+    /// @{
+
+    /*!
+    @brief clears the contents
+
+    Clears the content of a JSON value and resets it to the default value as
+    if @ref basic_json(value_t) would have been called:
+
+    Value type  | initial value
+    ----------- | -------------
+    null        | `null`
+    boolean     | `false`
+    string      | `""`
+    number      | `0`
+    object      | `{}`
+    array       | `[]`
+
+    @note Floating-point numbers are set to `0.0` which will be serialized to
+    `0`. The vale type remains @ref number_float_t.
+
+    @complexity Linear in the size of the JSON value.
+
+    @liveexample{The example below shows the effect of `clear()` to different
+    JSON types.,clear}
+
+    @since version 1.0.0
+    */
+    void clear() noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::number_integer:
+            {
+                m_value.number_integer = 0;
+                break;
+            }
+
+            case value_t::number_unsigned:
+            {
+                m_value.number_unsigned = 0;
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                m_value.number_float = 0.0;
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                m_value.boolean = false;
+                break;
+            }
+
+            case value_t::string:
+            {
+                m_value.string->clear();
+                break;
+            }
+
+            case value_t::array:
+            {
+                m_value.array->clear();
+                break;
+            }
+
+            case value_t::object:
+            {
+                m_value.object->clear();
+                break;
+            }
+
+            default:
+            {
+                break;
+            }
+        }
+    }
+
+    /*!
+    @brief add an object to an array
+
+    Appends the given element @a val to the end of the JSON value. If the
+    function is called on a JSON null value, an empty array is created before
+    appending @a val.
+
+    @param[in] val the value to add to the JSON array
+
+    @throw std::domain_error when called on a type other than JSON array or
+    null; example: `"cannot use push_back() with number"`
+
+    @complexity Amortized constant.
+
+    @liveexample{The example shows how `push_back()` and `+=` can be used to
+    add elements to a JSON array. Note how the `null` value was silently
+    converted to a JSON array.,push_back}
+
+    @since version 1.0.0
+    */
+    void push_back(basic_json&& val)
+    {
+        // push_back only works for null objects or arrays
+        if (not(is_null() or is_array()))
+        {
+            throw std::domain_error("cannot use push_back() with " + type_name());
+        }
+
+        // transform null object into an array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value = value_t::array;
+            assert_invariant();
+        }
+
+        // add element to array (move semantics)
+        m_value.array->push_back(std::move(val));
+        // invalidate object
+        val.m_type = value_t::null;
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    reference operator+=(basic_json&& val)
+    {
+        push_back(std::move(val));
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    void push_back(const basic_json& val)
+    {
+        // push_back only works for null objects or arrays
+        if (not(is_null() or is_array()))
+        {
+            throw std::domain_error("cannot use push_back() with " + type_name());
+        }
+
+        // transform null object into an array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value = value_t::array;
+            assert_invariant();
+        }
+
+        // add element to array
+        m_value.array->push_back(val);
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    reference operator+=(const basic_json& val)
+    {
+        push_back(val);
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an object
+
+    Inserts the given element @a val to the JSON object. If the function is
+    called on a JSON null value, an empty object is created before inserting
+    @a val.
+
+    @param[in] val the value to add to the JSON object
+
+    @throw std::domain_error when called on a type other than JSON object or
+    null; example: `"cannot use push_back() with number"`
+
+    @complexity Logarithmic in the size of the container, O(log(`size()`)).
+
+    @liveexample{The example shows how `push_back()` and `+=` can be used to
+    add elements to a JSON object. Note how the `null` value was silently
+    converted to a JSON object.,push_back__object_t__value}
+
+    @since version 1.0.0
+    */
+    void push_back(const typename object_t::value_type& val)
+    {
+        // push_back only works for null objects or objects
+        if (not(is_null() or is_object()))
+        {
+            throw std::domain_error("cannot use push_back() with " + type_name());
+        }
+
+        // transform null object into an object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value = value_t::object;
+            assert_invariant();
+        }
+
+        // add element to array
+        m_value.object->insert(val);
+    }
+
+    /*!
+    @brief add an object to an object
+    @copydoc push_back(const typename object_t::value_type&)
+    */
+    reference operator+=(const typename object_t::value_type& val)
+    {
+        push_back(val);
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an object
+
+    This function allows to use `push_back` with an initializer list. In case
+
+    1. the current value is an object,
+    2. the initializer list @a init contains only two elements, and
+    3. the first element of @a init is a string,
+
+    @a init is converted into an object element and added using
+    @ref push_back(const typename object_t::value_type&). Otherwise, @a init
+    is converted to a JSON value and added using @ref push_back(basic_json&&).
+
+    @param init  an initializer list
+
+    @complexity Linear in the size of the initializer list @a init.
+
+    @note This function is required to resolve an ambiguous overload error,
+          because pairs like `{"key", "value"}` can be both interpreted as
+          `object_t::value_type` or `std::initializer_list<basic_json>`, see
+          https://github.com/nlohmann/json/issues/235 for more information.
+
+    @liveexample{The example shows how initializer lists are treated as
+    objects when possible.,push_back__initializer_list}
+    */
+    void push_back(std::initializer_list<basic_json> init)
+    {
+        if (is_object() and init.size() == 2 and init.begin()->is_string())
+        {
+            const string_t key = *init.begin();
+            push_back(typename object_t::value_type(key, *(init.begin() + 1)));
+        }
+        else
+        {
+            push_back(basic_json(init));
+        }
+    }
+
+    /*!
+    @brief add an object to an object
+    @copydoc push_back(std::initializer_list<basic_json>)
+    */
+    reference operator+=(std::initializer_list<basic_json> init)
+    {
+        push_back(init);
+        return *this;
+    }
+
+    /*!
+    @brief inserts element
+
+    Inserts element @a val before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] val element to insert
+    @return iterator pointing to the inserted @a val.
+
+    @throw std::domain_error if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw std::domain_error if @a pos is not an iterator of *this; example:
+    `"iterator does not fit current value"`
+
+    @complexity Constant plus linear in the distance between pos and end of the
+    container.
+
+    @liveexample{The example shows how `insert()` is used.,insert}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, const basic_json& val)
+    {
+        // insert only works for arrays
+        if (is_array())
+        {
+            // check if iterator pos fits to this JSON value
+            if (pos.m_object != this)
+            {
+                throw std::domain_error("iterator does not fit current value");
+            }
+
+            // insert to array and return iterator
+            iterator result(this);
+            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
+            return result;
+        }
+        else
+        {
+            throw std::domain_error("cannot use insert() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief inserts element
+    @copydoc insert(const_iterator, const basic_json&)
+    */
+    iterator insert(const_iterator pos, basic_json&& val)
+    {
+        return insert(pos, val);
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts @a cnt copies of @a val before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] cnt number of copies of @a val to insert
+    @param[in] val element to insert
+    @return iterator pointing to the first element inserted, or @a pos if
+    `cnt==0`
+
+    @throw std::domain_error if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw std::domain_error if @a pos is not an iterator of *this; example:
+    `"iterator does not fit current value"`
+
+    @complexity Linear in @a cnt plus linear in the distance between @a pos
+    and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__count}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, size_type cnt, const basic_json& val)
+    {
+        // insert only works for arrays
+        if (is_array())
+        {
+            // check if iterator pos fits to this JSON value
+            if (pos.m_object != this)
+            {
+                throw std::domain_error("iterator does not fit current value");
+            }
+
+            // insert to array and return iterator
+            iterator result(this);
+            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
+            return result;
+        }
+        else
+        {
+            throw std::domain_error("cannot use insert() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts elements from range `[first, last)` before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] first begin of the range of elements to insert
+    @param[in] last end of the range of elements to insert
+
+    @throw std::domain_error if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw std::domain_error if @a pos is not an iterator of *this; example:
+    `"iterator does not fit current value"`
+    @throw std::domain_error if @a first and @a last do not belong to the same
+    JSON value; example: `"iterators do not fit"`
+    @throw std::domain_error if @a first or @a last are iterators into
+    container for which insert is called; example: `"passed iterators may not
+    belong to container"`
+
+    @return iterator pointing to the first element inserted, or @a pos if
+    `first==last`
+
+    @complexity Linear in `std::distance(first, last)` plus linear in the
+    distance between @a pos and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__range}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, const_iterator first, const_iterator last)
+    {
+        // insert only works for arrays
+        if (not is_array())
+        {
+            throw std::domain_error("cannot use insert() with " + type_name());
+        }
+
+        // check if iterator pos fits to this JSON value
+        if (pos.m_object != this)
+        {
+            throw std::domain_error("iterator does not fit current value");
+        }
+
+        // check if range iterators belong to the same JSON object
+        if (first.m_object != last.m_object)
+        {
+            throw std::domain_error("iterators do not fit");
+        }
+
+        if (first.m_object == this or last.m_object == this)
+        {
+            throw std::domain_error("passed iterators may not belong to container");
+        }
+
+        // insert to array and return iterator
+        iterator result(this);
+        result.m_it.array_iterator = m_value.array->insert(
+                                         pos.m_it.array_iterator,
+                                         first.m_it.array_iterator,
+                                         last.m_it.array_iterator);
+        return result;
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts elements from initializer list @a ilist before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] ilist initializer list to insert the values from
+
+    @throw std::domain_error if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw std::domain_error if @a pos is not an iterator of *this; example:
+    `"iterator does not fit current value"`
+
+    @return iterator pointing to the first element inserted, or @a pos if
+    `ilist` is empty
+
+    @complexity Linear in `ilist.size()` plus linear in the distance between
+    @a pos and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__ilist}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, std::initializer_list<basic_json> ilist)
+    {
+        // insert only works for arrays
+        if (not is_array())
+        {
+            throw std::domain_error("cannot use insert() with " + type_name());
+        }
+
+        // check if iterator pos fits to this JSON value
+        if (pos.m_object != this)
+        {
+            throw std::domain_error("iterator does not fit current value");
+        }
+
+        // insert to array and return iterator
+        iterator result(this);
+        result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, ilist);
+        return result;
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of the JSON value with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other JSON value to exchange the contents with
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how JSON values can be swapped with
+    `swap()`.,swap__reference}
+
+    @since version 1.0.0
+    */
+    void swap(reference other) noexcept (
+        std::is_nothrow_move_constructible<value_t>::value and
+        std::is_nothrow_move_assignable<value_t>::value and
+        std::is_nothrow_move_constructible<json_value>::value and
+        std::is_nothrow_move_assignable<json_value>::value
+    )
+    {
+        std::swap(m_type, other.m_type);
+        std::swap(m_value, other.m_value);
+        assert_invariant();
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON array with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other array to exchange the contents with
+
+    @throw std::domain_error when JSON value is not an array; example: `"cannot
+    use swap() with string"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how arrays can be swapped with
+    `swap()`.,swap__array_t}
+
+    @since version 1.0.0
+    */
+    void swap(array_t& other)
+    {
+        // swap only works for arrays
+        if (is_array())
+        {
+            std::swap(*(m_value.array), other);
+        }
+        else
+        {
+            throw std::domain_error("cannot use swap() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON object with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other object to exchange the contents with
+
+    @throw std::domain_error when JSON value is not an object; example:
+    `"cannot use swap() with string"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how objects can be swapped with
+    `swap()`.,swap__object_t}
+
+    @since version 1.0.0
+    */
+    void swap(object_t& other)
+    {
+        // swap only works for objects
+        if (is_object())
+        {
+            std::swap(*(m_value.object), other);
+        }
+        else
+        {
+            throw std::domain_error("cannot use swap() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON string with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other string to exchange the contents with
+
+    @throw std::domain_error when JSON value is not a string; example: `"cannot
+    use swap() with boolean"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how strings can be swapped with
+    `swap()`.,swap__string_t}
+
+    @since version 1.0.0
+    */
+    void swap(string_t& other)
+    {
+        // swap only works for strings
+        if (is_string())
+        {
+            std::swap(*(m_value.string), other);
+        }
+        else
+        {
+            throw std::domain_error("cannot use swap() with " + type_name());
+        }
+    }
+
+    /// @}
+
+
+    //////////////////////////////////////////
+    // lexicographical comparison operators //
+    //////////////////////////////////////////
+
+    /// @name lexicographical comparison operators
+    /// @{
+
+  private:
+    /*!
+    @brief comparison operator for JSON types
+
+    Returns an ordering that is similar to Python:
+    - order: null < boolean < number < object < array < string
+    - furthermore, each type is not smaller than itself
+
+    @since version 1.0.0
+    */
+    friend bool operator<(const value_t lhs, const value_t rhs) noexcept
+    {
+        static constexpr std::array<uint8_t, 8> order = {{
+                0, // null
+                3, // object
+                4, // array
+                5, // string
+                1, // boolean
+                2, // integer
+                2, // unsigned
+                2, // float
+            }
+        };
+
+        // discarded values are not comparable
+        if (lhs == value_t::discarded or rhs == value_t::discarded)
+        {
+            return false;
+        }
+
+        return order[static_cast<std::size_t>(lhs)] < order[static_cast<std::size_t>(rhs)];
+    }
+
+  public:
+    /*!
+    @brief comparison: equal
+
+    Compares two JSON values for equality according to the following rules:
+    - Two JSON values are equal if (1) they are from the same type and (2)
+      their stored values are the same.
+    - Integer and floating-point numbers are automatically converted before
+      comparison. Floating-point numbers are compared indirectly: two
+      floating-point numbers `f1` and `f2` are considered equal if neither
+      `f1 > f2` nor `f2 > f1` holds.
+    - Two JSON null values are equal.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether the values @a lhs and @a rhs are equal
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__equal}
+
+    @since version 1.0.0
+    */
+    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
+    {
+        const auto lhs_type = lhs.type();
+        const auto rhs_type = rhs.type();
+
+        if (lhs_type == rhs_type)
+        {
+            switch (lhs_type)
+            {
+                case value_t::array:
+                {
+                    return *lhs.m_value.array == *rhs.m_value.array;
+                }
+                case value_t::object:
+                {
+                    return *lhs.m_value.object == *rhs.m_value.object;
+                }
+                case value_t::null:
+                {
+                    return true;
+                }
+                case value_t::string:
+                {
+                    return *lhs.m_value.string == *rhs.m_value.string;
+                }
+                case value_t::boolean:
+                {
+                    return lhs.m_value.boolean == rhs.m_value.boolean;
+                }
+                case value_t::number_integer:
+                {
+                    return lhs.m_value.number_integer == rhs.m_value.number_integer;
+                }
+                case value_t::number_unsigned:
+                {
+                    return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned;
+                }
+                case value_t::number_float:
+                {
+                    return lhs.m_value.number_float == rhs.m_value.number_float;
+                }
+                default:
+                {
+                    return false;
+                }
+            }
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        {
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        {
+            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer;
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned);
+        }
+
+        return false;
+    }
+
+    /*!
+    @brief comparison: equal
+
+    The functions compares the given JSON value against a null pointer. As the
+    null pointer can be used to initialize a JSON value to null, a comparison
+    of JSON value @a v with a null pointer should be equivalent to call
+    `v.is_null()`.
+
+    @param[in] v  JSON value to consider
+    @return whether @a v is null
+
+    @complexity Constant.
+
+    @liveexample{The example compares several JSON types to the null pointer.
+    ,operator__equal__nullptr_t}
+
+    @since version 1.0.0
+    */
+    friend bool operator==(const_reference v, std::nullptr_t) noexcept
+    {
+        return v.is_null();
+    }
+
+    /*!
+    @brief comparison: equal
+    @copydoc operator==(const_reference, std::nullptr_t)
+    */
+    friend bool operator==(std::nullptr_t, const_reference v) noexcept
+    {
+        return v.is_null();
+    }
+
+    /*!
+    @brief comparison: not equal
+
+    Compares two JSON values for inequality by calculating `not (lhs == rhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether the values @a lhs and @a rhs are not equal
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__notequal}
+
+    @since version 1.0.0
+    */
+    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs == rhs);
+    }
+
+    /*!
+    @brief comparison: not equal
+
+    The functions compares the given JSON value against a null pointer. As the
+    null pointer can be used to initialize a JSON value to null, a comparison
+    of JSON value @a v with a null pointer should be equivalent to call
+    `not v.is_null()`.
+
+    @param[in] v  JSON value to consider
+    @return whether @a v is not null
+
+    @complexity Constant.
+
+    @liveexample{The example compares several JSON types to the null pointer.
+    ,operator__notequal__nullptr_t}
+
+    @since version 1.0.0
+    */
+    friend bool operator!=(const_reference v, std::nullptr_t) noexcept
+    {
+        return not v.is_null();
+    }
+
+    /*!
+    @brief comparison: not equal
+    @copydoc operator!=(const_reference, std::nullptr_t)
+    */
+    friend bool operator!=(std::nullptr_t, const_reference v) noexcept
+    {
+        return not v.is_null();
+    }
+
+    /*!
+    @brief comparison: less than
+
+    Compares whether one JSON value @a lhs is less than another JSON value @a
+    rhs according to the following rules:
+    - If @a lhs and @a rhs have the same type, the values are compared using
+      the default `<` operator.
+    - Integer and floating-point numbers are automatically converted before
+      comparison
+    - In case @a lhs and @a rhs have different types, the values are ignored
+      and the order of the types is considered, see
+      @ref operator<(const value_t, const value_t).
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is less than @a rhs
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__less}
+
+    @since version 1.0.0
+    */
+    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
+    {
+        const auto lhs_type = lhs.type();
+        const auto rhs_type = rhs.type();
+
+        if (lhs_type == rhs_type)
+        {
+            switch (lhs_type)
+            {
+                case value_t::array:
+                {
+                    return *lhs.m_value.array < *rhs.m_value.array;
+                }
+                case value_t::object:
+                {
+                    return *lhs.m_value.object < *rhs.m_value.object;
+                }
+                case value_t::null:
+                {
+                    return false;
+                }
+                case value_t::string:
+                {
+                    return *lhs.m_value.string < *rhs.m_value.string;
+                }
+                case value_t::boolean:
+                {
+                    return lhs.m_value.boolean < rhs.m_value.boolean;
+                }
+                case value_t::number_integer:
+                {
+                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
+                }
+                case value_t::number_unsigned:
+                {
+                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
+                }
+                case value_t::number_float:
+                {
+                    return lhs.m_value.number_float < rhs.m_value.number_float;
+                }
+                default:
+                {
+                    return false;
+                }
+            }
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        {
+            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        {
+            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
+        }
+
+        // We only reach this line if we cannot compare values. In that case,
+        // we compare types. Note we have to call the operator explicitly,
+        // because MSVC has problems otherwise.
+        return operator<(lhs_type, rhs_type);
+    }
+
+    /*!
+    @brief comparison: less than or equal
+
+    Compares whether one JSON value @a lhs is less than or equal to another
+    JSON value by calculating `not (rhs < lhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is less than or equal to @a rhs
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__greater}
+
+    @since version 1.0.0
+    */
+    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (rhs < lhs);
+    }
+
+    /*!
+    @brief comparison: greater than
+
+    Compares whether one JSON value @a lhs is greater than another
+    JSON value by calculating `not (lhs <= rhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is greater than to @a rhs
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__lessequal}
+
+    @since version 1.0.0
+    */
+    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs <= rhs);
+    }
+
+    /*!
+    @brief comparison: greater than or equal
+
+    Compares whether one JSON value @a lhs is greater than or equal to another
+    JSON value by calculating `not (lhs < rhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is greater than or equal to @a rhs
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__greaterequal}
+
+    @since version 1.0.0
+    */
+    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs < rhs);
+    }
+
+    /// @}
+
+
+    ///////////////////
+    // serialization //
+    ///////////////////
+
+    /// @name serialization
+    /// @{
+
+    /*!
+    @brief serialize to stream
+
+    Serialize the given JSON value @a j to the output stream @a o. The JSON
+    value will be serialized using the @ref dump member function. The
+    indentation of the output can be controlled with the member variable
+    `width` of the output stream @a o. For instance, using the manipulator
+    `std::setw(4)` on @a o sets the indentation level to `4` and the
+    serialization result is the same as calling `dump(4)`.
+
+    @note During serializaion, the locale and the precision of the output
+    stream @a o are changed. The original values are restored when the
+    function returns.
+
+    @param[in,out] o  stream to serialize to
+    @param[in] j  JSON value to serialize
+
+    @return the stream @a o
+
+    @complexity Linear.
+
+    @liveexample{The example below shows the serialization with different
+    parameters to `width` to adjust the indentation level.,operator_serialize}
+
+    @since version 1.0.0
+    */
+    friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
+    {
+        // read width member and use it as indentation parameter if nonzero
+        const bool pretty_print = (o.width() > 0);
+        const auto indentation = (pretty_print ? o.width() : 0);
+
+        // reset width to 0 for subsequent calls to this stream
+        o.width(0);
+
+        // fix locale problems
+        const auto old_locale = o.imbue(std::locale(std::locale(), new DecimalSeparator));
+        // set precision
+
+        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
+        // string->float->string, string->double->string or string->long
+        // double->string; to be safe, we read this value from
+        // std::numeric_limits<number_float_t>::digits10
+        const auto old_precision = o.precision(std::numeric_limits<double>::digits10);
+
+        // do the actual serialization
+        j.dump(o, pretty_print, static_cast<unsigned int>(indentation));
+
+        // reset locale and precision
+        o.imbue(old_locale);
+        o.precision(old_precision);
+        return o;
+    }
+
+    /*!
+    @brief serialize to stream
+    @copydoc operator<<(std::ostream&, const basic_json&)
+    */
+    friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
+    {
+        return o << j;
+    }
+
+    /// @}
+
+
+    /////////////////////
+    // deserialization //
+    /////////////////////
+
+    /// @name deserialization
+    /// @{
+
+    /*!
+    @brief deserialize from string
+
+    @param[in] s  string to read a serialized JSON value from
+    @param[in] cb a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @return result of the deserialization
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates the `parse()` function with
+    and without callback function.,parse__string__parser_callback_t}
+
+    @sa @ref parse(std::istream&, const parser_callback_t) for a version that
+    reads from an input stream
+
+    @since version 1.0.0
+    */
+    static basic_json parse(const string_t& s,
+                            const parser_callback_t cb = nullptr)
+    {
+        return parser(s, cb).parse();
+    }
+
+    /*!
+    @brief deserialize from stream
+
+    @param[in,out] i  stream to read a serialized JSON value from
+    @param[in] cb a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @return result of the deserialization
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates the `parse()` function with
+    and without callback function.,parse__istream__parser_callback_t}
+
+    @sa @ref parse(const string_t&, const parser_callback_t) for a version
+    that reads from a string
+
+    @since version 1.0.0
+    */
+    static basic_json parse(std::istream& i,
+                            const parser_callback_t cb = nullptr)
+    {
+        return parser(i, cb).parse();
+    }
+
+    /*!
+    @copydoc parse(std::istream&, const parser_callback_t)
+    */
+    static basic_json parse(std::istream&& i,
+                            const parser_callback_t cb = nullptr)
+    {
+        return parser(i, cb).parse();
+    }
+
+    /*!
+    @brief deserialize from stream
+
+    Deserializes an input stream to a JSON value.
+
+    @param[in,out] i  input stream to read a serialized JSON value from
+    @param[in,out] j  JSON value to write the deserialized input to
+
+    @throw std::invalid_argument in case of parse errors
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below shows how a JSON value is constructed by
+    reading a serialization from a stream.,operator_deserialize}
+
+    @sa parse(std::istream&, const parser_callback_t) for a variant with a
+    parser callback function to filter values while parsing
+
+    @since version 1.0.0
+    */
+    friend std::istream& operator<<(basic_json& j, std::istream& i)
+    {
+        j = parser(i).parse();
+        return i;
+    }
+
+    /*!
+    @brief deserialize from stream
+    @copydoc operator<<(basic_json&, std::istream&)
+    */
+    friend std::istream& operator>>(std::istream& i, basic_json& j)
+    {
+        j = parser(i).parse();
+        return i;
+    }
+
+    /// @}
+
+
+  private:
+    ///////////////////////////
+    // convenience functions //
+    ///////////////////////////
+
+    /*!
+    @brief return the type as string
+
+    Returns the type name as string to be used in error messages - usually to
+    indicate that a function was called on a wrong JSON type.
+
+    @return basically a string representation of a the @ref m_type member
+
+    @complexity Constant.
+
+    @since version 1.0.0
+    */
+    std::string type_name() const
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+                return "null";
+            case value_t::object:
+                return "object";
+            case value_t::array:
+                return "array";
+            case value_t::string:
+                return "string";
+            case value_t::boolean:
+                return "boolean";
+            case value_t::discarded:
+                return "discarded";
+            default:
+                return "number";
+        }
+    }
+
+    /*!
+    @brief calculates the extra space to escape a JSON string
+
+    @param[in] s  the string to escape
+    @return the number of characters required to escape string @a s
+
+    @complexity Linear in the length of string @a s.
+    */
+    static std::size_t extra_space(const string_t& s) noexcept
+    {
+        return std::accumulate(s.begin(), s.end(), size_t{},
+                               [](size_t res, typename string_t::value_type c)
+        {
+            switch (c)
+            {
+                case '"':
+                case '\\':
+                case '\b':
+                case '\f':
+                case '\n':
+                case '\r':
+                case '\t':
+                {
+                    // from c (1 byte) to \x (2 bytes)
+                    return res + 1;
+                }
+
+                default:
+                {
+                    if (c >= 0x00 and c <= 0x1f)
+                    {
+                        // from c (1 byte) to \uxxxx (6 bytes)
+                        return res + 5;
+                    }
+                    else
+                    {
+                        return res;
+                    }
+                }
+            }
+        });
+    }
+
+    /*!
+    @brief escape a string
+
+    Escape a string by replacing certain special characters by a sequence of
+    an escape character (backslash) and another character and other control
+    characters by a sequence of "\u" followed by a four-digit hex
+    representation.
+
+    @param[in] s  the string to escape
+    @return  the escaped string
+
+    @complexity Linear in the length of string @a s.
+    */
+    static string_t escape_string(const string_t& s)
+    {
+        const auto space = extra_space(s);
+        if (space == 0)
+        {
+            return s;
+        }
+
+        // create a result string of necessary size
+        string_t result(s.size() + space, '\\');
+        std::size_t pos = 0;
+
+        for (const auto& c : s)
+        {
+            switch (c)
+            {
+                // quotation mark (0x22)
+                case '"':
+                {
+                    result[pos + 1] = '"';
+                    pos += 2;
+                    break;
+                }
+
+                // reverse solidus (0x5c)
+                case '\\':
+                {
+                    // nothing to change
+                    pos += 2;
+                    break;
+                }
+
+                // backspace (0x08)
+                case '\b':
+                {
+                    result[pos + 1] = 'b';
+                    pos += 2;
+                    break;
+                }
+
+                // formfeed (0x0c)
+                case '\f':
+                {
+                    result[pos + 1] = 'f';
+                    pos += 2;
+                    break;
+                }
+
+                // newline (0x0a)
+                case '\n':
+                {
+                    result[pos + 1] = 'n';
+                    pos += 2;
+                    break;
+                }
+
+                // carriage return (0x0d)
+                case '\r':
+                {
+                    result[pos + 1] = 'r';
+                    pos += 2;
+                    break;
+                }
+
+                // horizontal tab (0x09)
+                case '\t':
+                {
+                    result[pos + 1] = 't';
+                    pos += 2;
+                    break;
+                }
+
+                default:
+                {
+                    if (c >= 0x00 and c <= 0x1f)
+                    {
+                        // convert a number 0..15 to its hex representation
+                        // (0..f)
+                        static const char hexify[16] =
+                        {
+                            '0', '1', '2', '3', '4', '5', '6', '7',
+                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
+                        };
+
+                        // print character c as \uxxxx
+                        for (const char m :
+                    { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f]
+                        })
+                        {
+                            result[++pos] = m;
+                        }
+
+                        ++pos;
+                    }
+                    else
+                    {
+                        // all other characters are added as-is
+                        result[pos++] = c;
+                    }
+                    break;
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief internal implementation of the serialization function
+
+    This function is called by the public member function dump and organizes
+    the serialization internally. The indentation level is propagated as
+    additional parameter. In case of arrays and objects, the function is
+    called recursively. Note that
+
+    - strings and object keys are escaped using `escape_string()`
+    - integer numbers are converted implicitly via `operator<<`
+    - floating-point numbers are converted to a string using `"%g"` format
+
+    @param[out] o              stream to write to
+    @param[in] pretty_print    whether the output shall be pretty-printed
+    @param[in] indent_step     the indent level
+    @param[in] current_indent  the current indent level (only used internally)
+    */
+    void dump(std::ostream& o,
+              const bool pretty_print,
+              const unsigned int indent_step,
+              const unsigned int current_indent = 0) const
+    {
+        // variable to hold indentation for recursive calls
+        unsigned int new_indent = current_indent;
+
+        switch (m_type)
+        {
+            case value_t::object:
+            {
+                if (m_value.object->empty())
+                {
+                    o << "{}";
+                    return;
+                }
+
+                o << "{";
+
+                // increase indentation
+                if (pretty_print)
+                {
+                    new_indent += indent_step;
+                    o << "\n";
+                }
+
+                for (auto i = m_value.object->cbegin(); i != m_value.object->cend(); ++i)
+                {
+                    if (i != m_value.object->cbegin())
+                    {
+                        o << (pretty_print ? ",\n" : ",");
+                    }
+                    o << string_t(new_indent, ' ') << "\""
+                      << escape_string(i->first) << "\":"
+                      << (pretty_print ? " " : "");
+                    i->second.dump(o, pretty_print, indent_step, new_indent);
+                }
+
+                // decrease indentation
+                if (pretty_print)
+                {
+                    new_indent -= indent_step;
+                    o << "\n";
+                }
+
+                o << string_t(new_indent, ' ') + "}";
+                return;
+            }
+
+            case value_t::array:
+            {
+                if (m_value.array->empty())
+                {
+                    o << "[]";
+                    return;
+                }
+
+                o << "[";
+
+                // increase indentation
+                if (pretty_print)
+                {
+                    new_indent += indent_step;
+                    o << "\n";
+                }
+
+                for (auto i = m_value.array->cbegin(); i != m_value.array->cend(); ++i)
+                {
+                    if (i != m_value.array->cbegin())
+                    {
+                        o << (pretty_print ? ",\n" : ",");
+                    }
+                    o << string_t(new_indent, ' ');
+                    i->dump(o, pretty_print, indent_step, new_indent);
+                }
+
+                // decrease indentation
+                if (pretty_print)
+                {
+                    new_indent -= indent_step;
+                    o << "\n";
+                }
+
+                o << string_t(new_indent, ' ') << "]";
+                return;
+            }
+
+            case value_t::string:
+            {
+                o << string_t("\"") << escape_string(*m_value.string) << "\"";
+                return;
+            }
+
+            case value_t::boolean:
+            {
+                o << (m_value.boolean ? "true" : "false");
+                return;
+            }
+
+            case value_t::number_integer:
+            {
+                o << m_value.number_integer;
+                return;
+            }
+
+            case value_t::number_unsigned:
+            {
+                o << m_value.number_unsigned;
+                return;
+            }
+
+            case value_t::number_float:
+            {
+                if (m_value.number_float == 0)
+                {
+                    // special case for zero to get "0.0"/"-0.0"
+                    o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
+                }
+                else
+                {
+                    o << m_value.number_float;
+                }
+                return;
+            }
+
+            case value_t::discarded:
+            {
+                o << "<discarded>";
+                return;
+            }
+
+            case value_t::null:
+            {
+                o << "null";
+                return;
+            }
+        }
+    }
+
+  private:
+    //////////////////////
+    // member variables //
+    //////////////////////
+
+    /// the type of the current element
+    value_t m_type = value_t::null;
+
+    /// the value of the current element
+    json_value m_value = {};
+
+
+  private:
+    ///////////////
+    // iterators //
+    ///////////////
+
+    /*!
+    @brief an iterator for primitive JSON types
+
+    This class models an iterator for primitive JSON types (boolean, number,
+    string). It's only purpose is to allow the iterator/const_iterator classes
+    to "iterate" over primitive values. Internally, the iterator is modeled by
+    a `difference_type` variable. Value begin_value (`0`) models the begin,
+    end_value (`1`) models past the end.
+    */
+    class primitive_iterator_t
+    {
+      public:
+        /// set iterator to a defined beginning
+        void set_begin() noexcept
+        {
+            m_it = begin_value;
+        }
+
+        /// set iterator to a defined past the end
+        void set_end() noexcept
+        {
+            m_it = end_value;
+        }
+
+        /// return whether the iterator can be dereferenced
+        constexpr bool is_begin() const noexcept
+        {
+            return (m_it == begin_value);
+        }
+
+        /// return whether the iterator is at end
+        constexpr bool is_end() const noexcept
+        {
+            return (m_it == end_value);
+        }
+
+        /// return reference to the value to change and compare
+        operator difference_type& () noexcept
+        {
+            return m_it;
+        }
+
+        /// return value to compare
+        constexpr operator difference_type () const noexcept
+        {
+            return m_it;
+        }
+
+      private:
+        static constexpr difference_type begin_value = 0;
+        static constexpr difference_type end_value = begin_value + 1;
+
+        /// iterator as signed integer type
+        difference_type m_it = std::numeric_limits<std::ptrdiff_t>::denorm_min();
+    };
+
+    /*!
+    @brief an iterator value
+
+    @note This structure could easily be a union, but MSVC currently does not
+    allow unions members with complex constructors, see
+    https://github.com/nlohmann/json/pull/105.
+    */
+    struct internal_iterator
+    {
+        /// iterator for JSON objects
+        typename object_t::iterator object_iterator;
+        /// iterator for JSON arrays
+        typename array_t::iterator array_iterator;
+        /// generic iterator for all other types
+        primitive_iterator_t primitive_iterator;
+
+        /// create an uninitialized internal_iterator
+        internal_iterator() noexcept
+            : object_iterator(), array_iterator(), primitive_iterator()
+        {}
+    };
+
+    /// proxy class for the iterator_wrapper functions
+    template<typename IteratorType>
+    class iteration_proxy
+    {
+      private:
+        /// helper class for iteration
+        class iteration_proxy_internal
+        {
+          private:
+            /// the iterator
+            IteratorType anchor;
+            /// an index for arrays (used to create key names)
+            size_t array_index = 0;
+
+          public:
+            explicit iteration_proxy_internal(IteratorType it) noexcept
+                : anchor(it)
+            {}
+
+            /// dereference operator (needed for range-based for)
+            iteration_proxy_internal& operator*()
+            {
+                return *this;
+            }
+
+            /// increment operator (needed for range-based for)
+            iteration_proxy_internal& operator++()
+            {
+                ++anchor;
+                ++array_index;
+
+                return *this;
+            }
+
+            /// inequality operator (needed for range-based for)
+            bool operator!= (const iteration_proxy_internal& o) const
+            {
+                return anchor != o.anchor;
+            }
+
+            /// return key of the iterator
+            typename basic_json::string_t key() const
+            {
+                assert(anchor.m_object != nullptr);
+
+                switch (anchor.m_object->type())
+                {
+                    // use integer array index as key
+                    case value_t::array:
+                    {
+                        return std::to_string(array_index);
+                    }
+
+                    // use key from the object
+                    case value_t::object:
+                    {
+                        return anchor.key();
+                    }
+
+                    // use an empty key for all primitive types
+                    default:
+                    {
+                        return "";
+                    }
+                }
+            }
+
+            /// return value of the iterator
+            typename IteratorType::reference value() const
+            {
+                return anchor.value();
+            }
+        };
+
+        /// the container to iterate
+        typename IteratorType::reference container;
+
+      public:
+        /// construct iteration proxy from a container
+        explicit iteration_proxy(typename IteratorType::reference cont)
+            : container(cont)
+        {}
+
+        /// return iterator begin (needed for range-based for)
+        iteration_proxy_internal begin() noexcept
+        {
+            return iteration_proxy_internal(container.begin());
+        }
+
+        /// return iterator end (needed for range-based for)
+        iteration_proxy_internal end() noexcept
+        {
+            return iteration_proxy_internal(container.end());
+        }
+    };
+
+  public:
+    /*!
+    @brief a const random access iterator for the @ref basic_json class
+
+    This class implements a const iterator for the @ref basic_json class. From
+    this class, the @ref iterator class is derived.
+
+    @note An iterator is called *initialized* when a pointer to a JSON value
+          has been set (e.g., by a constructor or a copy assignment). If the
+          iterator is default-constructed, it is *uninitialized* and most
+          methods are undefined. The library uses assertions to detect calls
+          on uninitialized iterators.
+
+    @requirement The class satisfies the following concept requirements:
+    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
+      The iterator that can be moved to point (forward and backward) to any
+      element in constant time.
+
+    @since version 1.0.0
+    */
+    class const_iterator : public std::iterator<std::random_access_iterator_tag, const basic_json>
+    {
+        /// allow basic_json to access private members
+        friend class basic_json;
+
+      public:
+        /// the type of the values when the iterator is dereferenced
+        using value_type = typename basic_json::value_type;
+        /// a type to represent differences between iterators
+        using difference_type = typename basic_json::difference_type;
+        /// defines a pointer to the type iterated over (value_type)
+        using pointer = typename basic_json::const_pointer;
+        /// defines a reference to the type iterated over (value_type)
+        using reference = typename basic_json::const_reference;
+        /// the category of the iterator
+        using iterator_category = std::bidirectional_iterator_tag;
+
+        /// default constructor
+        const_iterator() = default;
+
+        /*!
+        @brief constructor for a given JSON instance
+        @param[in] object  pointer to a JSON object for this iterator
+        @pre object != nullptr
+        @post The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        explicit const_iterator(pointer object) noexcept
+            : m_object(object)
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    m_it.object_iterator = typename object_t::iterator();
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    m_it.array_iterator = typename array_t::iterator();
+                    break;
+                }
+
+                default:
+                {
+                    m_it.primitive_iterator = primitive_iterator_t();
+                    break;
+                }
+            }
+        }
+
+        /*!
+        @brief copy constructor given a non-const iterator
+        @param[in] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
+        explicit const_iterator(const iterator& other) noexcept
+            : m_object(other.m_object)
+        {
+            if (m_object != nullptr)
+            {
+                switch (m_object->m_type)
+                {
+                    case basic_json::value_t::object:
+                    {
+                        m_it.object_iterator = other.m_it.object_iterator;
+                        break;
+                    }
+
+                    case basic_json::value_t::array:
+                    {
+                        m_it.array_iterator = other.m_it.array_iterator;
+                        break;
+                    }
+
+                    default:
+                    {
+                        m_it.primitive_iterator = other.m_it.primitive_iterator;
+                        break;
+                    }
+                }
+            }
+        }
+
+        /*!
+        @brief copy constructor
+        @param[in] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
+        const_iterator(const const_iterator& other) noexcept
+            : m_object(other.m_object), m_it(other.m_it)
+        {}
+
+        /*!
+        @brief copy assignment
+        @param[in,out] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
+        const_iterator& operator=(const_iterator other) noexcept(
+            std::is_nothrow_move_constructible<pointer>::value and
+            std::is_nothrow_move_assignable<pointer>::value and
+            std::is_nothrow_move_constructible<internal_iterator>::value and
+            std::is_nothrow_move_assignable<internal_iterator>::value
+        )
+        {
+            std::swap(m_object, other.m_object);
+            std::swap(m_it, other.m_it);
+            return *this;
+        }
+
+      private:
+        /*!
+        @brief set the iterator to the first value
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        void set_begin() noexcept
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    m_it.object_iterator = m_object->m_value.object->begin();
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    m_it.array_iterator = m_object->m_value.array->begin();
+                    break;
+                }
+
+                case basic_json::value_t::null:
+                {
+                    // set to end so begin()==end() is true: null is empty
+                    m_it.primitive_iterator.set_end();
+                    break;
+                }
+
+                default:
+                {
+                    m_it.primitive_iterator.set_begin();
+                    break;
+                }
+            }
+        }
+
+        /*!
+        @brief set the iterator past the last value
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        void set_end() noexcept
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    m_it.object_iterator = m_object->m_value.object->end();
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    m_it.array_iterator = m_object->m_value.array->end();
+                    break;
+                }
+
+                default:
+                {
+                    m_it.primitive_iterator.set_end();
+                    break;
+                }
+            }
+        }
+
+      public:
+        /*!
+        @brief return a reference to the value pointed to by the iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        reference operator*() const
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    assert(m_it.object_iterator != m_object->m_value.object->end());
+                    return m_it.object_iterator->second;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    assert(m_it.array_iterator != m_object->m_value.array->end());
+                    return *m_it.array_iterator;
+                }
+
+                case basic_json::value_t::null:
+                {
+                    throw std::out_of_range("cannot get value");
+                }
+
+                default:
+                {
+                    if (m_it.primitive_iterator.is_begin())
+                    {
+                        return *m_object;
+                    }
+                    else
+                    {
+                        throw std::out_of_range("cannot get value");
+                    }
+                }
+            }
+        }
+
+        /*!
+        @brief dereference the iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        pointer operator->() const
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    assert(m_it.object_iterator != m_object->m_value.object->end());
+                    return &(m_it.object_iterator->second);
+                }
+
+                case basic_json::value_t::array:
+                {
+                    assert(m_it.array_iterator != m_object->m_value.array->end());
+                    return &*m_it.array_iterator;
+                }
+
+                default:
+                {
+                    if (m_it.primitive_iterator.is_begin())
+                    {
+                        return m_object;
+                    }
+                    else
+                    {
+                        throw std::out_of_range("cannot get value");
+                    }
+                }
+            }
+        }
+
+        /*!
+        @brief post-increment (it++)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator operator++(int)
+        {
+            auto result = *this;
+            ++(*this);
+            return result;
+        }
+
+        /*!
+        @brief pre-increment (++it)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator& operator++()
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    std::advance(m_it.object_iterator, 1);
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    std::advance(m_it.array_iterator, 1);
+                    break;
+                }
+
+                default:
+                {
+                    ++m_it.primitive_iterator;
+                    break;
+                }
+            }
+
+            return *this;
+        }
+
+        /*!
+        @brief post-decrement (it--)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator operator--(int)
+        {
+            auto result = *this;
+            --(*this);
+            return result;
+        }
+
+        /*!
+        @brief pre-decrement (--it)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator& operator--()
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    std::advance(m_it.object_iterator, -1);
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    std::advance(m_it.array_iterator, -1);
+                    break;
+                }
+
+                default:
+                {
+                    --m_it.primitive_iterator;
+                    break;
+                }
+            }
+
+            return *this;
+        }
+
+        /*!
+        @brief  comparison: equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator==(const const_iterator& other) const
+        {
+            // if objects are not the same, the comparison is undefined
+            if (m_object != other.m_object)
+            {
+                throw std::domain_error("cannot compare iterators of different containers");
+            }
+
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    return (m_it.object_iterator == other.m_it.object_iterator);
+                }
+
+                case basic_json::value_t::array:
+                {
+                    return (m_it.array_iterator == other.m_it.array_iterator);
+                }
+
+                default:
+                {
+                    return (m_it.primitive_iterator == other.m_it.primitive_iterator);
+                }
+            }
+        }
+
+        /*!
+        @brief  comparison: not equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator!=(const const_iterator& other) const
+        {
+            return not operator==(other);
+        }
+
+        /*!
+        @brief  comparison: smaller
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator<(const const_iterator& other) const
+        {
+            // if objects are not the same, the comparison is undefined
+            if (m_object != other.m_object)
+            {
+                throw std::domain_error("cannot compare iterators of different containers");
+            }
+
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    throw std::domain_error("cannot compare order of object iterators");
+                }
+
+                case basic_json::value_t::array:
+                {
+                    return (m_it.array_iterator < other.m_it.array_iterator);
+                }
+
+                default:
+                {
+                    return (m_it.primitive_iterator < other.m_it.primitive_iterator);
+                }
+            }
+        }
+
+        /*!
+        @brief  comparison: less than or equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator<=(const const_iterator& other) const
+        {
+            return not other.operator < (*this);
+        }
+
+        /*!
+        @brief  comparison: greater than
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator>(const const_iterator& other) const
+        {
+            return not operator<=(other);
+        }
+
+        /*!
+        @brief  comparison: greater than or equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator>=(const const_iterator& other) const
+        {
+            return not operator<(other);
+        }
+
+        /*!
+        @brief  add to iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator& operator+=(difference_type i)
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    throw std::domain_error("cannot use offsets with object iterators");
+                }
+
+                case basic_json::value_t::array:
+                {
+                    std::advance(m_it.array_iterator, i);
+                    break;
+                }
+
+                default:
+                {
+                    m_it.primitive_iterator += i;
+                    break;
+                }
+            }
+
+            return *this;
+        }
+
+        /*!
+        @brief  subtract from iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator& operator-=(difference_type i)
+        {
+            return operator+=(-i);
+        }
+
+        /*!
+        @brief  add to iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator operator+(difference_type i)
+        {
+            auto result = *this;
+            result += i;
+            return result;
+        }
+
+        /*!
+        @brief  subtract from iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator operator-(difference_type i)
+        {
+            auto result = *this;
+            result -= i;
+            return result;
+        }
+
+        /*!
+        @brief  return difference
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        difference_type operator-(const const_iterator& other) const
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    throw std::domain_error("cannot use offsets with object iterators");
+                }
+
+                case basic_json::value_t::array:
+                {
+                    return m_it.array_iterator - other.m_it.array_iterator;
+                }
+
+                default:
+                {
+                    return m_it.primitive_iterator - other.m_it.primitive_iterator;
+                }
+            }
+        }
+
+        /*!
+        @brief  access to successor
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        reference operator[](difference_type n) const
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    throw std::domain_error("cannot use operator[] for object iterators");
+                }
+
+                case basic_json::value_t::array:
+                {
+                    return *std::next(m_it.array_iterator, n);
+                }
+
+                case basic_json::value_t::null:
+                {
+                    throw std::out_of_range("cannot get value");
+                }
+
+                default:
+                {
+                    if (m_it.primitive_iterator == -n)
+                    {
+                        return *m_object;
+                    }
+                    else
+                    {
+                        throw std::out_of_range("cannot get value");
+                    }
+                }
+            }
+        }
+
+        /*!
+        @brief  return the key of an object iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        typename object_t::key_type key() const
+        {
+            assert(m_object != nullptr);
+
+            if (m_object->is_object())
+            {
+                return m_it.object_iterator->first;
+            }
+            else
+            {
+                throw std::domain_error("cannot use key() for non-object iterators");
+            }
+        }
+
+        /*!
+        @brief  return the value of an iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        reference value() const
+        {
+            return operator*();
+        }
+
+      private:
+        /// associated JSON instance
+        pointer m_object = nullptr;
+        /// the actual iterator of the associated instance
+        internal_iterator m_it = internal_iterator();
+    };
+
+    /*!
+    @brief a mutable random access iterator for the @ref basic_json class
+
+    @requirement The class satisfies the following concept requirements:
+    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
+      The iterator that can be moved to point (forward and backward) to any
+      element in constant time.
+    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
+      It is possible to write to the pointed-to element.
+
+    @since version 1.0.0
+    */
+    class iterator : public const_iterator
+    {
+      public:
+        using base_iterator = const_iterator;
+        using pointer = typename basic_json::pointer;
+        using reference = typename basic_json::reference;
+
+        /// default constructor
+        iterator() = default;
+
+        /// constructor for a given JSON instance
+        explicit iterator(pointer object) noexcept
+            : base_iterator(object)
+        {}
+
+        /// copy constructor
+        iterator(const iterator& other) noexcept
+            : base_iterator(other)
+        {}
+
+        /// copy assignment
+        iterator& operator=(iterator other) noexcept(
+            std::is_nothrow_move_constructible<pointer>::value and
+            std::is_nothrow_move_assignable<pointer>::value and
+            std::is_nothrow_move_constructible<internal_iterator>::value and
+            std::is_nothrow_move_assignable<internal_iterator>::value
+        )
+        {
+            base_iterator::operator=(other);
+            return *this;
+        }
+
+        /// return a reference to the value pointed to by the iterator
+        reference operator*() const
+        {
+            return const_cast<reference>(base_iterator::operator*());
+        }
+
+        /// dereference the iterator
+        pointer operator->() const
+        {
+            return const_cast<pointer>(base_iterator::operator->());
+        }
+
+        /// post-increment (it++)
+        iterator operator++(int)
+        {
+            iterator result = *this;
+            base_iterator::operator++();
+            return result;
+        }
+
+        /// pre-increment (++it)
+        iterator& operator++()
+        {
+            base_iterator::operator++();
+            return *this;
+        }
+
+        /// post-decrement (it--)
+        iterator operator--(int)
+        {
+            iterator result = *this;
+            base_iterator::operator--();
+            return result;
+        }
+
+        /// pre-decrement (--it)
+        iterator& operator--()
+        {
+            base_iterator::operator--();
+            return *this;
+        }
+
+        /// add to iterator
+        iterator& operator+=(difference_type i)
+        {
+            base_iterator::operator+=(i);
+            return *this;
+        }
+
+        /// subtract from iterator
+        iterator& operator-=(difference_type i)
+        {
+            base_iterator::operator-=(i);
+            return *this;
+        }
+
+        /// add to iterator
+        iterator operator+(difference_type i)
+        {
+            auto result = *this;
+            result += i;
+            return result;
+        }
+
+        /// subtract from iterator
+        iterator operator-(difference_type i)
+        {
+            auto result = *this;
+            result -= i;
+            return result;
+        }
+
+        /// return difference
+        difference_type operator-(const iterator& other) const
+        {
+            return base_iterator::operator-(other);
+        }
+
+        /// access to successor
+        reference operator[](difference_type n) const
+        {
+            return const_cast<reference>(base_iterator::operator[](n));
+        }
+
+        /// return the value of an iterator
+        reference value() const
+        {
+            return const_cast<reference>(base_iterator::value());
+        }
+    };
+
+    /*!
+    @brief a template for a reverse iterator class
+
+    @tparam Base the base iterator type to reverse. Valid types are @ref
+    iterator (to create @ref reverse_iterator) and @ref const_iterator (to
+    create @ref const_reverse_iterator).
+
+    @requirement The class satisfies the following concept requirements:
+    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
+      The iterator that can be moved to point (forward and backward) to any
+      element in constant time.
+    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
+      It is possible to write to the pointed-to element (only if @a Base is
+      @ref iterator).
+
+    @since version 1.0.0
+    */
+    template<typename Base>
+    class json_reverse_iterator : public std::reverse_iterator<Base>
+    {
+      public:
+        /// shortcut to the reverse iterator adaptor
+        using base_iterator = std::reverse_iterator<Base>;
+        /// the reference type for the pointed-to element
+        using reference = typename Base::reference;
+
+        /// create reverse iterator from iterator
+        json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept
+            : base_iterator(it)
+        {}
+
+        /// create reverse iterator from base class
+        json_reverse_iterator(const base_iterator& it) noexcept
+            : base_iterator(it)
+        {}
+
+        /// post-increment (it++)
+        json_reverse_iterator operator++(int)
+        {
+            return base_iterator::operator++(1);
+        }
+
+        /// pre-increment (++it)
+        json_reverse_iterator& operator++()
+        {
+            base_iterator::operator++();
+            return *this;
+        }
+
+        /// post-decrement (it--)
+        json_reverse_iterator operator--(int)
+        {
+            return base_iterator::operator--(1);
+        }
+
+        /// pre-decrement (--it)
+        json_reverse_iterator& operator--()
+        {
+            base_iterator::operator--();
+            return *this;
+        }
+
+        /// add to iterator
+        json_reverse_iterator& operator+=(difference_type i)
+        {
+            base_iterator::operator+=(i);
+            return *this;
+        }
+
+        /// add to iterator
+        json_reverse_iterator operator+(difference_type i) const
+        {
+            auto result = *this;
+            result += i;
+            return result;
+        }
+
+        /// subtract from iterator
+        json_reverse_iterator operator-(difference_type i) const
+        {
+            auto result = *this;
+            result -= i;
+            return result;
+        }
+
+        /// return difference
+        difference_type operator-(const json_reverse_iterator& other) const
+        {
+            return this->base() - other.base();
+        }
+
+        /// access to successor
+        reference operator[](difference_type n) const
+        {
+            return *(this->operator+(n));
+        }
+
+        /// return the key of an object iterator
+        typename object_t::key_type key() const
+        {
+            auto it = --this->base();
+            return it.key();
+        }
+
+        /// return the value of an iterator
+        reference value() const
+        {
+            auto it = --this->base();
+            return it.operator * ();
+        }
+    };
+
+
+  private:
+    //////////////////////
+    // lexer and parser //
+    //////////////////////
+
+    /*!
+    @brief lexical analysis
+
+    This class organizes the lexical analysis during JSON deserialization. The
+    core of it is a scanner generated by [re2c](http://re2c.org) that
+    processes a buffer and recognizes tokens according to RFC 7159.
+    */
+    class lexer
+    {
+      public:
+        /// token types for the parser
+        enum class token_type
+        {
+            uninitialized,   ///< indicating the scanner is uninitialized
+            literal_true,    ///< the `true` literal
+            literal_false,   ///< the `false` literal
+            literal_null,    ///< the `null` literal
+            value_string,    ///< a string -- use get_string() for actual value
+            value_number,    ///< a number -- use get_number() for actual value
+            begin_array,     ///< the character for array begin `[`
+            begin_object,    ///< the character for object begin `{`
+            end_array,       ///< the character for array end `]`
+            end_object,      ///< the character for object end `}`
+            name_separator,  ///< the name separator `:`
+            value_separator, ///< the value separator `,`
+            parse_error,     ///< indicating a parse error
+            end_of_input     ///< indicating the end of the input buffer
+        };
+
+        /// the char type to use in the lexer
+        using lexer_char_t = unsigned char;
+
+        /// constructor with a given buffer
+        explicit lexer(const string_t& s) noexcept
+            : m_stream(nullptr), m_buffer(s)
+        {
+            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
+            assert(m_content != nullptr);
+            m_start = m_cursor = m_content;
+            m_limit = m_content + s.size();
+        }
+
+        /// constructor with a given stream
+        explicit lexer(std::istream* s) noexcept
+            : m_stream(s), m_buffer()
+        {
+            assert(m_stream != nullptr);
+            std::getline(*m_stream, m_buffer);
+            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
+            assert(m_content != nullptr);
+            m_start = m_cursor = m_content;
+            m_limit = m_content + m_buffer.size();
+        }
+
+        /// default constructor
+        lexer() = default;
+
+        // switch off unwanted functions
+        lexer(const lexer&) = delete;
+        lexer operator=(const lexer&) = delete;
+
+        /*!
+        @brief create a string from one or two Unicode code points
+
+        There are two cases: (1) @a codepoint1 is in the Basic Multilingual
+        Plane (U+0000 through U+FFFF) and @a codepoint2 is 0, or (2)
+        @a codepoint1 and @a codepoint2 are a UTF-16 surrogate pair to
+        represent a code point above U+FFFF.
+
+        @param[in] codepoint1  the code point (can be high surrogate)
+        @param[in] codepoint2  the code point (can be low surrogate or 0)
+
+        @return string representation of the code point; the length of the
+        result string is between 1 and 4 characters.
+
+        @throw std::out_of_range if code point is > 0x10ffff; example: `"code
+        points above 0x10FFFF are invalid"`
+        @throw std::invalid_argument if the low surrogate is invalid; example:
+        `""missing or wrong low surrogate""`
+
+        @complexity Constant.
+
+        @see <http://en.wikipedia.org/wiki/UTF-8#Sample_code>
+        */
+        static string_t to_unicode(const std::size_t codepoint1,
+                                   const std::size_t codepoint2 = 0)
+        {
+            // calculate the code point from the given code points
+            std::size_t codepoint = codepoint1;
+
+            // check if codepoint1 is a high surrogate
+            if (codepoint1 >= 0xD800 and codepoint1 <= 0xDBFF)
+            {
+                // check if codepoint2 is a low surrogate
+                if (codepoint2 >= 0xDC00 and codepoint2 <= 0xDFFF)
+                {
+                    codepoint =
+                        // high surrogate occupies the most significant 22 bits
+                        (codepoint1 << 10)
+                        // low surrogate occupies the least significant 15 bits
+                        + codepoint2
+                        // there is still the 0xD800, 0xDC00 and 0x10000 noise
+                        // in the result so we have to subtract with:
+                        // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
+                        - 0x35FDC00;
+                }
+                else
+                {
+                    throw std::invalid_argument("missing or wrong low surrogate");
+                }
+            }
+
+            string_t result;
+
+            if (codepoint < 0x80)
+            {
+                // 1-byte characters: 0xxxxxxx (ASCII)
+                result.append(1, static_cast<typename string_t::value_type>(codepoint));
+            }
+            else if (codepoint <= 0x7ff)
+            {
+                // 2-byte characters: 110xxxxx 10xxxxxx
+                result.append(1, static_cast<typename string_t::value_type>(0xC0 | ((codepoint >> 6) & 0x1F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
+            }
+            else if (codepoint <= 0xffff)
+            {
+                // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
+                result.append(1, static_cast<typename string_t::value_type>(0xE0 | ((codepoint >> 12) & 0x0F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
+            }
+            else if (codepoint <= 0x10ffff)
+            {
+                // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+                result.append(1, static_cast<typename string_t::value_type>(0xF0 | ((codepoint >> 18) & 0x07)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 12) & 0x3F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
+            }
+            else
+            {
+                throw std::out_of_range("code points above 0x10FFFF are invalid");
+            }
+
+            return result;
+        }
+
+        /// return name of values of type token_type (only used for errors)
+        static std::string token_type_name(const token_type t)
+        {
+            switch (t)
+            {
+                case token_type::uninitialized:
+                    return "<uninitialized>";
+                case token_type::literal_true:
+                    return "true literal";
+                case token_type::literal_false:
+                    return "false literal";
+                case token_type::literal_null:
+                    return "null literal";
+                case token_type::value_string:
+                    return "string literal";
+                case token_type::value_number:
+                    return "number literal";
+                case token_type::begin_array:
+                    return "'['";
+                case token_type::begin_object:
+                    return "'{'";
+                case token_type::end_array:
+                    return "']'";
+                case token_type::end_object:
+                    return "'}'";
+                case token_type::name_separator:
+                    return "':'";
+                case token_type::value_separator:
+                    return "','";
+                case token_type::parse_error:
+                    return "<parse error>";
+                case token_type::end_of_input:
+                    return "end of input";
+                default:
+                {
+                    // catch non-enum values
+                    return "unknown token"; // LCOV_EXCL_LINE
+                }
+            }
+        }
+
+        /*!
+        This function implements a scanner for JSON. It is specified using
+        regular expressions that try to follow RFC 7159 as close as possible.
+        These regular expressions are then translated into a minimized
+        deterministic finite automaton (DFA) by the tool
+        [re2c](http://re2c.org). As a result, the translated code for this
+        function consists of a large block of code with `goto` jumps.
+
+        @return the class of the next token read from the buffer
+
+        @complexity Linear in the length of the input.\n
+
+        Proposition: The loop below will always terminate for finite input.\n
+
+        Proof (by contradiction): Assume a finite input. To loop forever, the
+        loop must never hit code with a `break` statement. The only code
+        snippets without a `break` statement are the continue statements for
+        whitespace and byte-order-marks. To loop forever, the input must be an
+        infinite sequence of whitespace or byte-order-marks. This contradicts
+        the assumption of finite input, q.e.d.
+        */
+        token_type scan() noexcept
+        {
+            while (true)
+            {
+                // pointer for backtracking information
+                m_marker = nullptr;
+
+                // remember the begin of the token
+                m_start = m_cursor;
+                assert(m_start != nullptr);
+
+
+                {
+                    lexer_char_t yych;
+                    unsigned int yyaccept = 0;
+                    static const unsigned char yybm[] =
+                    {
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,  32,  32,   0,   0,  32,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        160, 128,   0, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        192, 192, 192, 192, 192, 192, 192, 192,
+                        192, 192, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128,   0, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                    };
+                    if ((m_limit - m_cursor) < 5)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 32)
+                    {
+                        goto basic_json_parser_6;
+                    }
+                    if (yych <= '\\')
+                    {
+                        if (yych <= '-')
+                        {
+                            if (yych <= '"')
+                            {
+                                if (yych <= 0x00)
+                                {
+                                    goto basic_json_parser_2;
+                                }
+                                if (yych <= '!')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_9;
+                            }
+                            else
+                            {
+                                if (yych <= '+')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                if (yych <= ',')
+                                {
+                                    goto basic_json_parser_10;
+                                }
+                                goto basic_json_parser_12;
+                            }
+                        }
+                        else
+                        {
+                            if (yych <= '9')
+                            {
+                                if (yych <= '/')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                if (yych <= '0')
+                                {
+                                    goto basic_json_parser_13;
+                                }
+                                goto basic_json_parser_15;
+                            }
+                            else
+                            {
+                                if (yych <= ':')
+                                {
+                                    goto basic_json_parser_17;
+                                }
+                                if (yych == '[')
+                                {
+                                    goto basic_json_parser_19;
+                                }
+                                goto basic_json_parser_4;
+                            }
+                        }
+                    }
+                    else
+                    {
+                        if (yych <= 't')
+                        {
+                            if (yych <= 'f')
+                            {
+                                if (yych <= ']')
+                                {
+                                    goto basic_json_parser_21;
+                                }
+                                if (yych <= 'e')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_23;
+                            }
+                            else
+                            {
+                                if (yych == 'n')
+                                {
+                                    goto basic_json_parser_24;
+                                }
+                                if (yych <= 's')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_25;
+                            }
+                        }
+                        else
+                        {
+                            if (yych <= '|')
+                            {
+                                if (yych == '{')
+                                {
+                                    goto basic_json_parser_26;
+                                }
+                                goto basic_json_parser_4;
+                            }
+                            else
+                            {
+                                if (yych <= '}')
+                                {
+                                    goto basic_json_parser_28;
+                                }
+                                if (yych == 0xEF)
+                                {
+                                    goto basic_json_parser_30;
+                                }
+                                goto basic_json_parser_4;
+                            }
+                        }
+                    }
+basic_json_parser_2:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_of_input;
+                        break;
+                    }
+basic_json_parser_4:
+                    ++m_cursor;
+basic_json_parser_5:
+                    {
+                        last_token_type = token_type::parse_error;
+                        break;
+                    }
+basic_json_parser_6:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 32)
+                    {
+                        goto basic_json_parser_6;
+                    }
+                    {
+                        continue;
+                    }
+basic_json_parser_9:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych <= 0x1F)
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_10:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::value_separator;
+                        break;
+                    }
+basic_json_parser_12:
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    if (yych <= '0')
+                    {
+                        goto basic_json_parser_13;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_15;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_13:
+                    yyaccept = 1;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych <= 'D')
+                    {
+                        if (yych == '.')
+                        {
+                            goto basic_json_parser_37;
+                        }
+                    }
+                    else
+                    {
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                    }
+basic_json_parser_14:
+                    {
+                        last_token_type = token_type::value_number;
+                        break;
+                    }
+basic_json_parser_15:
+                    yyaccept = 1;
+                    m_marker = ++m_cursor;
+                    if ((m_limit - m_cursor) < 3)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 64)
+                    {
+                        goto basic_json_parser_15;
+                    }
+                    if (yych <= 'D')
+                    {
+                        if (yych == '.')
+                        {
+                            goto basic_json_parser_37;
+                        }
+                        goto basic_json_parser_14;
+                    }
+                    else
+                    {
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        goto basic_json_parser_14;
+                    }
+basic_json_parser_17:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::name_separator;
+                        break;
+                    }
+basic_json_parser_19:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::begin_array;
+                        break;
+                    }
+basic_json_parser_21:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_array;
+                        break;
+                    }
+basic_json_parser_23:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'a')
+                    {
+                        goto basic_json_parser_39;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_24:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'u')
+                    {
+                        goto basic_json_parser_40;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_25:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'r')
+                    {
+                        goto basic_json_parser_41;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_26:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::begin_object;
+                        break;
+                    }
+basic_json_parser_28:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_object;
+                        break;
+                    }
+basic_json_parser_30:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 0xBB)
+                    {
+                        goto basic_json_parser_42;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_31:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+basic_json_parser_32:
+                    if (yybm[0 + yych] & 128)
+                    {
+                        goto basic_json_parser_31;
+                    }
+                    if (yych <= 0x1F)
+                    {
+                        goto basic_json_parser_33;
+                    }
+                    if (yych <= '"')
+                    {
+                        goto basic_json_parser_34;
+                    }
+                    goto basic_json_parser_36;
+basic_json_parser_33:
+                    m_cursor = m_marker;
+                    if (yyaccept == 0)
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    else
+                    {
+                        goto basic_json_parser_14;
+                    }
+basic_json_parser_34:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::value_string;
+                        break;
+                    }
+basic_json_parser_36:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 'e')
+                    {
+                        if (yych <= '/')
+                        {
+                            if (yych == '"')
+                            {
+                                goto basic_json_parser_31;
+                            }
+                            if (yych <= '.')
+                            {
+                                goto basic_json_parser_33;
+                            }
+                            goto basic_json_parser_31;
+                        }
+                        else
+                        {
+                            if (yych <= '\\')
+                            {
+                                if (yych <= '[')
+                                {
+                                    goto basic_json_parser_33;
+                                }
+                                goto basic_json_parser_31;
+                            }
+                            else
+                            {
+                                if (yych == 'b')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                goto basic_json_parser_33;
+                            }
+                        }
+                    }
+                    else
+                    {
+                        if (yych <= 'q')
+                        {
+                            if (yych <= 'f')
+                            {
+                                goto basic_json_parser_31;
+                            }
+                            if (yych == 'n')
+                            {
+                                goto basic_json_parser_31;
+                            }
+                            goto basic_json_parser_33;
+                        }
+                        else
+                        {
+                            if (yych <= 's')
+                            {
+                                if (yych <= 'r')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                goto basic_json_parser_33;
+                            }
+                            else
+                            {
+                                if (yych <= 't')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                if (yych <= 'u')
+                                {
+                                    goto basic_json_parser_43;
+                                }
+                                goto basic_json_parser_33;
+                            }
+                        }
+                    }
+basic_json_parser_37:
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_33;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_44;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_38:
+                    yych = *++m_cursor;
+                    if (yych <= ',')
+                    {
+                        if (yych == '+')
+                        {
+                            goto basic_json_parser_46;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= '-')
+                        {
+                            goto basic_json_parser_46;
+                        }
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_47;
+                        }
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_39:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
+                    {
+                        goto basic_json_parser_49;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_40:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
+                    {
+                        goto basic_json_parser_50;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_41:
+                    yych = *++m_cursor;
+                    if (yych == 'u')
+                    {
+                        goto basic_json_parser_51;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_42:
+                    yych = *++m_cursor;
+                    if (yych == 0xBF)
+                    {
+                        goto basic_json_parser_52;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_43:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_54;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_54;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_54;
+                        }
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_44:
+                    yyaccept = 1;
+                    m_marker = ++m_cursor;
+                    if ((m_limit - m_cursor) < 3)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 'D')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_14;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_44;
+                        }
+                        goto basic_json_parser_14;
+                    }
+                    else
+                    {
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        goto basic_json_parser_14;
+                    }
+basic_json_parser_46:
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_33;
+                    }
+                    if (yych >= ':')
+                    {
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_47:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_14;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_47;
+                    }
+                    goto basic_json_parser_14;
+basic_json_parser_49:
+                    yych = *++m_cursor;
+                    if (yych == 's')
+                    {
+                        goto basic_json_parser_55;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_50:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
+                    {
+                        goto basic_json_parser_56;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_51:
+                    yych = *++m_cursor;
+                    if (yych == 'e')
+                    {
+                        goto basic_json_parser_58;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_52:
+                    ++m_cursor;
+                    {
+                        continue;
+                    }
+basic_json_parser_54:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_60;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_60;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_60;
+                        }
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_55:
+                    yych = *++m_cursor;
+                    if (yych == 'e')
+                    {
+                        goto basic_json_parser_61;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_56:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::literal_null;
+                        break;
+                    }
+basic_json_parser_58:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::literal_true;
+                        break;
+                    }
+basic_json_parser_60:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_63;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_63;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_63;
+                        }
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_61:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::literal_false;
+                        break;
+                    }
+basic_json_parser_63:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_31;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_31;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_31;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                }
+
+            }
+
+            return last_token_type;
+        }
+
+        /// append data from the stream to the internal buffer
+        void yyfill() noexcept
+        {
+            if (m_stream == nullptr or not * m_stream)
+            {
+                return;
+            }
+
+            const auto offset_start = m_start - m_content;
+            const auto offset_marker = m_marker - m_start;
+            const auto offset_cursor = m_cursor - m_start;
+
+            m_buffer.erase(0, static_cast<size_t>(offset_start));
+            std::string line;
+            assert(m_stream != nullptr);
+            std::getline(*m_stream, line);
+            m_buffer += "\n" + line; // add line with newline symbol
+
+            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
+            assert(m_content != nullptr);
+            m_start  = m_content;
+            m_marker = m_start + offset_marker;
+            m_cursor = m_start + offset_cursor;
+            m_limit  = m_start + m_buffer.size() - 1;
+        }
+
+        /// return string representation of last read token
+        string_t get_token_string() const
+        {
+            assert(m_start != nullptr);
+            return string_t(reinterpret_cast<typename string_t::const_pointer>(m_start),
+                            static_cast<size_t>(m_cursor - m_start));
+        }
+
+        /*!
+        @brief return string value for string tokens
+
+        The function iterates the characters between the opening and closing
+        quotes of the string value. The complete string is the range
+        [m_start,m_cursor). Consequently, we iterate from m_start+1 to
+        m_cursor-1.
+
+        We differentiate two cases:
+
+        1. Escaped characters. In this case, a new character is constructed
+           according to the nature of the escape. Some escapes create new
+           characters (e.g., `"\\n"` is replaced by `"\n"`), some are copied
+           as is (e.g., `"\\\\"`). Furthermore, Unicode escapes of the shape
+           `"\\uxxxx"` need special care. In this case, to_unicode takes care
+           of the construction of the values.
+        2. Unescaped characters are copied as is.
+
+        @pre `m_cursor - m_start >= 2`, meaning the length of the last token
+        is at least 2 bytes which is trivially true for any string (which
+        consists of at least two quotes).
+
+            " c1 c2 c3 ... "
+            ^                ^
+            m_start          m_cursor
+
+        @complexity Linear in the length of the string.\n
+
+        Lemma: The loop body will always terminate.\n
+
+        Proof (by contradiction): Assume the loop body does not terminate. As
+        the loop body does not contain another loop, one of the called
+        functions must never return. The called functions are `std::strtoul`
+        and to_unicode. Neither function can loop forever, so the loop body
+        will never loop forever which contradicts the assumption that the loop
+        body does not terminate, q.e.d.\n
+
+        Lemma: The loop condition for the for loop is eventually false.\n
+
+        Proof (by contradiction): Assume the loop does not terminate. Due to
+        the above lemma, this can only be due to a tautological loop
+        condition; that is, the loop condition i < m_cursor - 1 must always be
+        true. Let x be the change of i for any loop iteration. Then
+        m_start + 1 + x < m_cursor - 1 must hold to loop indefinitely. This
+        can be rephrased to m_cursor - m_start - 2 > x. With the
+        precondition, we x <= 0, meaning that the loop condition holds
+        indefinitly if i is always decreased. However, observe that the value
+        of i is strictly increasing with each iteration, as it is incremented
+        by 1 in the iteration expression and never decremented inside the loop
+        body. Hence, the loop condition will eventually be false which
+        contradicts the assumption that the loop condition is a tautology,
+        q.e.d.
+
+        @return string value of current token without opening and closing
+        quotes
+        @throw std::out_of_range if to_unicode fails
+        */
+        string_t get_string() const
+        {
+            assert(m_cursor - m_start >= 2);
+
+            string_t result;
+            result.reserve(static_cast<size_t>(m_cursor - m_start - 2));
+
+            // iterate the result between the quotes
+            for (const lexer_char_t* i = m_start + 1; i < m_cursor - 1; ++i)
+            {
+                // process escaped characters
+                if (*i == '\\')
+                {
+                    // read next character
+                    ++i;
+
+                    switch (*i)
+                    {
+                        // the default escapes
+                        case 't':
+                        {
+                            result += "\t";
+                            break;
+                        }
+                        case 'b':
+                        {
+                            result += "\b";
+                            break;
+                        }
+                        case 'f':
+                        {
+                            result += "\f";
+                            break;
+                        }
+                        case 'n':
+                        {
+                            result += "\n";
+                            break;
+                        }
+                        case 'r':
+                        {
+                            result += "\r";
+                            break;
+                        }
+                        case '\\':
+                        {
+                            result += "\\";
+                            break;
+                        }
+                        case '/':
+                        {
+                            result += "/";
+                            break;
+                        }
+                        case '"':
+                        {
+                            result += "\"";
+                            break;
+                        }
+
+                        // unicode
+                        case 'u':
+                        {
+                            // get code xxxx from uxxxx
+                            auto codepoint = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>(i + 1),
+                                                          4).c_str(), nullptr, 16);
+
+                            // check if codepoint is a high surrogate
+                            if (codepoint >= 0xD800 and codepoint <= 0xDBFF)
+                            {
+                                // make sure there is a subsequent unicode
+                                if ((i + 6 >= m_limit) or * (i + 5) != '\\' or * (i + 6) != 'u')
+                                {
+                                    throw std::invalid_argument("missing low surrogate");
+                                }
+
+                                // get code yyyy from uxxxx\uyyyy
+                                auto codepoint2 = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>
+                                                               (i + 7), 4).c_str(), nullptr, 16);
+                                result += to_unicode(codepoint, codepoint2);
+                                // skip the next 10 characters (xxxx\uyyyy)
+                                i += 10;
+                            }
+                            else
+                            {
+                                // add unicode character(s)
+                                result += to_unicode(codepoint);
+                                // skip the next four characters (xxxx)
+                                i += 4;
+                            }
+                            break;
+                        }
+                    }
+                }
+                else
+                {
+                    // all other characters are just copied to the end of the
+                    // string
+                    result.append(1, static_cast<typename string_t::value_type>(*i));
+                }
+            }
+
+            return result;
+        }
+
+        /*!
+        @brief parse floating point number
+
+        This function (and its overloads) serves to select the most approprate
+        standard floating point number parsing function based on the type
+        supplied via the first parameter.  Set this to @a
+        static_cast<number_float_t*>(nullptr).
+
+        @param[in] type  the @ref number_float_t in use
+
+        @param[in,out] endptr recieves a pointer to the first character after
+        the number
+
+        @return the floating point number
+        */
+        long double str_to_float_t(long double* /* type */, char** endptr) const
+        {
+            return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
+        }
+
+        /*!
+        @brief parse floating point number
+
+        This function (and its overloads) serves to select the most approprate
+        standard floating point number parsing function based on the type
+        supplied via the first parameter.  Set this to @a
+        static_cast<number_float_t*>(nullptr).
+
+        @param[in] type  the @ref number_float_t in use
+
+        @param[in,out] endptr  recieves a pointer to the first character after
+        the number
+
+        @return the floating point number
+        */
+        double str_to_float_t(double* /* type */, char** endptr) const
+        {
+            return std::strtod(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
+        }
+
+        /*!
+        @brief parse floating point number
+
+        This function (and its overloads) serves to select the most approprate
+        standard floating point number parsing function based on the type
+        supplied via the first parameter.  Set this to @a
+        static_cast<number_float_t*>(nullptr).
+
+        @param[in] type  the @ref number_float_t in use
+
+        @param[in,out] endptr  recieves a pointer to the first character after
+        the number
+
+        @return the floating point number
+        */
+        float str_to_float_t(float* /* type */, char** endptr) const
+        {
+            return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
+        }
+
+        /*!
+        @brief return number value for number tokens
+
+        This function translates the last token into the most appropriate
+        number type (either integer, unsigned integer or floating point),
+        which is passed back to the caller via the result parameter.
+
+        This function parses the integer component up to the radix point or
+        exponent while collecting information about the 'floating point
+        representation', which it stores in the result parameter. If there is
+        no radix point or exponent, and the number can fit into a @ref
+        number_integer_t or @ref number_unsigned_t then it sets the result
+        parameter accordingly.
+
+        If the number is a floating point number the number is then parsed
+        using @a std:strtod (or @a std:strtof or @a std::strtold).
+
+        @param[out] result  @ref basic_json object to receive the number, or
+        NAN if the conversion read past the current token. The latter case
+        needs to be treated by the caller function.
+        */
+        void get_number(basic_json& result) const
+        {
+            assert(m_start != nullptr);
+
+            const lexer::lexer_char_t* curptr = m_start;
+
+            // accumulate the integer conversion result (unsigned for now)
+            number_unsigned_t value = 0;
+
+            // maximum absolute value of the relevant integer type
+            number_unsigned_t max;
+
+            // temporarily store the type to avoid unecessary bitfield access
+            value_t type;
+
+            // look for sign
+            if (*curptr == '-')
+            {
+                type = value_t::number_integer;
+                max = static_cast<uint64_t>((std::numeric_limits<number_integer_t>::max)()) + 1;
+                curptr++;
+            }
+            else
+            {
+                type = value_t::number_unsigned;
+                max = static_cast<uint64_t>((std::numeric_limits<number_unsigned_t>::max)());
+            }
+
+            // count the significant figures
+            for (; curptr < m_cursor; curptr++)
+            {
+                // quickly skip tests if a digit
+                if (*curptr < '0' || *curptr > '9')
+                {
+                    if (*curptr == '.')
+                    {
+                        // don't count '.' but change to float
+                        type = value_t::number_float;
+                        continue;
+                    }
+                    // assume exponent (if not then will fail parse): change to
+                    // float, stop counting and record exponent details
+                    type = value_t::number_float;
+                    break;
+                }
+
+                // skip if definitely not an integer
+                if (type != value_t::number_float)
+                {
+                    // multiply last value by ten and add the new digit
+                    auto temp = value * 10 + *curptr - '0';
+
+                    // test for overflow
+                    if (temp < value || temp > max)
+                    {
+                        // overflow
+                        type = value_t::number_float;
+                    }
+                    else
+                    {
+                        // no overflow - save it
+                        value = temp;
+                    }
+                }
+            }
+
+            // save the value (if not a float)
+            if (type == value_t::number_unsigned)
+            {
+                result.m_value.number_unsigned = value;
+            }
+            else if (type == value_t::number_integer)
+            {
+                result.m_value.number_integer = -static_cast<number_integer_t>(value);
+            }
+            else
+            {
+                // parse with strtod
+                result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
+            }
+
+            // save the type
+            result.m_type = type;
+        }
+
+      private:
+        /// optional input stream
+        std::istream* m_stream = nullptr;
+        /// the buffer
+        string_t m_buffer;
+        /// the buffer pointer
+        const lexer_char_t* m_content = nullptr;
+        /// pointer to the beginning of the current symbol
+        const lexer_char_t* m_start = nullptr;
+        /// pointer for backtracking information
+        const lexer_char_t* m_marker = nullptr;
+        /// pointer to the current symbol
+        const lexer_char_t* m_cursor = nullptr;
+        /// pointer to the end of the buffer
+        const lexer_char_t* m_limit = nullptr;
+        /// the last token type
+        token_type last_token_type = token_type::end_of_input;
+    };
+
+    /*!
+    @brief syntax analysis
+
+    This class implements a recursive decent parser.
+    */
+    class parser
+    {
+      public:
+        /// constructor for strings
+        parser(const string_t& s, const parser_callback_t cb = nullptr) noexcept
+            : callback(cb), m_lexer(s)
+        {
+            // read first token
+            get_token();
+        }
+
+        /// a parser reading from an input stream
+        parser(std::istream& _is, const parser_callback_t cb = nullptr) noexcept
+            : callback(cb), m_lexer(&_is)
+        {
+            // read first token
+            get_token();
+        }
+
+        /// public parser interface
+        basic_json parse()
+        {
+            basic_json result = parse_internal(true);
+            result.assert_invariant();
+
+            expect(lexer::token_type::end_of_input);
+
+            // return parser result and replace it with null in case the
+            // top-level value was discarded by the callback function
+            return result.is_discarded() ? basic_json() : std::move(result);
+        }
+
+      private:
+        /// the actual parser
+        basic_json parse_internal(bool keep)
+        {
+            auto result = basic_json(value_t::discarded);
+
+            switch (last_token)
+            {
+                case lexer::token_type::begin_object:
+                {
+                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::object_start, result))))
+                    {
+                        // explicitly set result to object to cope with {}
+                        result.m_type = value_t::object;
+                        result.m_value = value_t::object;
+                    }
+
+                    // read next token
+                    get_token();
+
+                    // closing } -> we are done
+                    if (last_token == lexer::token_type::end_object)
+                    {
+                        get_token();
+                        if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
+                        {
+                            result = basic_json(value_t::discarded);
+                        }
+                        return result;
+                    }
+
+                    // no comma is expected here
+                    unexpect(lexer::token_type::value_separator);
+
+                    // otherwise: parse key-value pairs
+                    do
+                    {
+                        // ugly, but could be fixed with loop reorganization
+                        if (last_token == lexer::token_type::value_separator)
+                        {
+                            get_token();
+                        }
+
+                        // store key
+                        expect(lexer::token_type::value_string);
+                        const auto key = m_lexer.get_string();
+
+                        bool keep_tag = false;
+                        if (keep)
+                        {
+                            if (callback)
+                            {
+                                basic_json k(key);
+                                keep_tag = callback(depth, parse_event_t::key, k);
+                            }
+                            else
+                            {
+                                keep_tag = true;
+                            }
+                        }
+
+                        // parse separator (:)
+                        get_token();
+                        expect(lexer::token_type::name_separator);
+
+                        // parse and add value
+                        get_token();
+                        auto value = parse_internal(keep);
+                        if (keep and keep_tag and not value.is_discarded())
+                        {
+                            result[key] = std::move(value);
+                        }
+                    }
+                    while (last_token == lexer::token_type::value_separator);
+
+                    // closing }
+                    expect(lexer::token_type::end_object);
+                    get_token();
+                    if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
+                    {
+                        result = basic_json(value_t::discarded);
+                    }
+
+                    return result;
+                }
+
+                case lexer::token_type::begin_array:
+                {
+                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::array_start, result))))
+                    {
+                        // explicitly set result to object to cope with []
+                        result.m_type = value_t::array;
+                        result.m_value = value_t::array;
+                    }
+
+                    // read next token
+                    get_token();
+
+                    // closing ] -> we are done
+                    if (last_token == lexer::token_type::end_array)
+                    {
+                        get_token();
+                        if (callback and not callback(--depth, parse_event_t::array_end, result))
+                        {
+                            result = basic_json(value_t::discarded);
+                        }
+                        return result;
+                    }
+
+                    // no comma is expected here
+                    unexpect(lexer::token_type::value_separator);
+
+                    // otherwise: parse values
+                    do
+                    {
+                        // ugly, but could be fixed with loop reorganization
+                        if (last_token == lexer::token_type::value_separator)
+                        {
+                            get_token();
+                        }
+
+                        // parse value
+                        auto value = parse_internal(keep);
+                        if (keep and not value.is_discarded())
+                        {
+                            result.push_back(std::move(value));
+                        }
+                    }
+                    while (last_token == lexer::token_type::value_separator);
+
+                    // closing ]
+                    expect(lexer::token_type::end_array);
+                    get_token();
+                    if (keep and callback and not callback(--depth, parse_event_t::array_end, result))
+                    {
+                        result = basic_json(value_t::discarded);
+                    }
+
+                    return result;
+                }
+
+                case lexer::token_type::literal_null:
+                {
+                    get_token();
+                    result.m_type = value_t::null;
+                    break;
+                }
+
+                case lexer::token_type::value_string:
+                {
+                    const auto s = m_lexer.get_string();
+                    get_token();
+                    result = basic_json(s);
+                    break;
+                }
+
+                case lexer::token_type::literal_true:
+                {
+                    get_token();
+                    result.m_type = value_t::boolean;
+                    result.m_value = true;
+                    break;
+                }
+
+                case lexer::token_type::literal_false:
+                {
+                    get_token();
+                    result.m_type = value_t::boolean;
+                    result.m_value = false;
+                    break;
+                }
+
+                case lexer::token_type::value_number:
+                {
+                    m_lexer.get_number(result);
+                    get_token();
+                    break;
+                }
+
+                default:
+                {
+                    // the last token was unexpected
+                    unexpect(last_token);
+                }
+            }
+
+            if (keep and callback and not callback(depth, parse_event_t::value, result))
+            {
+                result = basic_json(value_t::discarded);
+            }
+            return result;
+        }
+
+        /// get next token from lexer
+        typename lexer::token_type get_token() noexcept
+        {
+            last_token = m_lexer.scan();
+            return last_token;
+        }
+
+        void expect(typename lexer::token_type t) const
+        {
+            if (t != last_token)
+            {
+                std::string error_msg = "parse error - unexpected ";
+                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
+                              "'") :
+                              lexer::token_type_name(last_token));
+                error_msg += "; expected " + lexer::token_type_name(t);
+                throw std::invalid_argument(error_msg);
+            }
+        }
+
+        void unexpect(typename lexer::token_type t) const
+        {
+            if (t == last_token)
+            {
+                std::string error_msg = "parse error - unexpected ";
+                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
+                              "'") :
+                              lexer::token_type_name(last_token));
+                throw std::invalid_argument(error_msg);
+            }
+        }
+
+      private:
+        /// current level of recursion
+        int depth = 0;
+        /// callback function
+        const parser_callback_t callback = nullptr;
+        /// the type of the last read token
+        typename lexer::token_type last_token = lexer::token_type::uninitialized;
+        /// the lexer
+        lexer m_lexer;
+    };
+
+  public:
+    /*!
+    @brief JSON Pointer
+
+    A JSON pointer defines a string syntax for identifying a specific value
+    within a JSON document. It can be used with functions `at` and
+    `operator[]`. Furthermore, JSON pointers are the base for JSON patches.
+
+    @sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
+
+    @since version 2.0.0
+    */
+    class json_pointer
+    {
+        /// allow basic_json to access private members
+        friend class basic_json;
+
+      public:
+        /*!
+        @brief create JSON pointer
+
+        Create a JSON pointer according to the syntax described in
+        [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3).
+
+        @param[in] s  string representing the JSON pointer; if omitted, the
+                      empty string is assumed which references the whole JSON
+                      value
+
+        @throw std::domain_error if reference token is nonempty and does not
+        begin with a slash (`/`); example: `"JSON pointer must be empty or
+        begin with /"`
+        @throw std::domain_error if a tilde (`~`) is not followed by `0`
+        (representing `~`) or `1` (representing `/`); example: `"escape error:
+        ~ must be followed with 0 or 1"`
+
+        @liveexample{The example shows the construction several valid JSON
+        pointers as well as the exceptional behavior.,json_pointer}
+
+        @since version 2.0.0
+        */
+        explicit json_pointer(const std::string& s = "")
+            : reference_tokens(split(s))
+        {}
+
+        /*!
+        @brief return a string representation of the JSON pointer
+
+        @invariant For each JSON pointer `ptr`, it holds:
+        @code {.cpp}
+        ptr == json_pointer(ptr.to_string());
+        @endcode
+
+        @return a string representation of the JSON pointer
+
+        @liveexample{The example shows the result of `to_string`.,
+        json_pointer__to_string}
+
+        @since version 2.0.0
+        */
+        std::string to_string() const noexcept
+        {
+            return std::accumulate(reference_tokens.begin(),
+                                   reference_tokens.end(), std::string{},
+                                   [](const std::string & a, const std::string & b)
+            {
+                return a + "/" + escape(b);
+            });
+        }
+
+        /// @copydoc to_string()
+        operator std::string() const
+        {
+            return to_string();
+        }
+
+      private:
+        /// remove and return last reference pointer
+        std::string pop_back()
+        {
+            if (is_root())
+            {
+                throw std::domain_error("JSON pointer has no parent");
+            }
+
+            auto last = reference_tokens.back();
+            reference_tokens.pop_back();
+            return last;
+        }
+
+        /// return whether pointer points to the root document
+        bool is_root() const
+        {
+            return reference_tokens.empty();
+        }
+
+        json_pointer top() const
+        {
+            if (is_root())
+            {
+                throw std::domain_error("JSON pointer has no parent");
+            }
+
+            json_pointer result = *this;
+            result.reference_tokens = {reference_tokens[0]};
+            return result;
+        }
+
+        /*!
+        @brief create and return a reference to the pointed to value
+
+        @complexity Linear in the number of reference tokens.
+        */
+        reference get_and_create(reference j) const
+        {
+            pointer result = &j;
+
+            // in case no reference tokens exist, return a reference to the
+            // JSON value j which will be overwritten by a primitive value
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (result->m_type)
+                {
+                    case value_t::null:
+                    {
+                        if (reference_token == "0")
+                        {
+                            // start a new array if reference token is 0
+                            result = &result->operator[](0);
+                        }
+                        else
+                        {
+                            // start a new object otherwise
+                            result = &result->operator[](reference_token);
+                        }
+                        break;
+                    }
+
+                    case value_t::object:
+                    {
+                        // create an entry in the object
+                        result = &result->operator[](reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        // create an entry in the array
+                        result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        break;
+                    }
+
+                    /*
+                    The following code is only reached if there exists a
+                    reference token _and_ the current value is primitive. In
+                    this case, we have an error situation, because primitive
+                    values may only occur as single value; that is, with an
+                    empty list of reference tokens.
+                    */
+                    default:
+                    {
+                        throw std::domain_error("invalid value to unflatten");
+                    }
+                }
+            }
+
+            return *result;
+        }
+
+        /*!
+        @brief return a reference to the pointed to value
+
+        @param[in] ptr  a JSON value
+
+        @return reference to the JSON value pointed to by the JSON pointer
+
+        @complexity Linear in the length of the JSON pointer.
+
+        @throw std::out_of_range      if the JSON pointer can not be resolved
+        @throw std::domain_error      if an array index begins with '0'
+        @throw std::invalid_argument  if an array index was not a number
+        */
+        reference get_unchecked(pointer ptr) const
+        {
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (ptr->m_type)
+                {
+                    case value_t::object:
+                    {
+                        // use unchecked object access
+                        ptr = &ptr->operator[](reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        // error condition (cf. RFC 6901, Sect. 4)
+                        if (reference_token.size() > 1 and reference_token[0] == '0')
+                        {
+                            throw std::domain_error("array index must not begin with '0'");
+                        }
+
+                        if (reference_token == "-")
+                        {
+                            // explicityly treat "-" as index beyond the end
+                            ptr = &ptr->operator[](ptr->m_value.array->size());
+                        }
+                        else
+                        {
+                            // convert array index to number; unchecked access
+                            ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        }
+                        break;
+                    }
+
+                    default:
+                    {
+                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                    }
+                }
+            }
+
+            return *ptr;
+        }
+
+        reference get_checked(pointer ptr) const
+        {
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (ptr->m_type)
+                {
+                    case value_t::object:
+                    {
+                        // note: at performs range check
+                        ptr = &ptr->at(reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        if (reference_token == "-")
+                        {
+                            // "-" always fails the range check
+                            throw std::out_of_range("array index '-' (" +
+                                                    std::to_string(ptr->m_value.array->size()) +
+                                                    ") is out of range");
+                        }
+
+                        // error condition (cf. RFC 6901, Sect. 4)
+                        if (reference_token.size() > 1 and reference_token[0] == '0')
+                        {
+                            throw std::domain_error("array index must not begin with '0'");
+                        }
+
+                        // note: at performs range check
+                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
+                        break;
+                    }
+
+                    default:
+                    {
+                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                    }
+                }
+            }
+
+            return *ptr;
+        }
+
+        /*!
+        @brief return a const reference to the pointed to value
+
+        @param[in] ptr  a JSON value
+
+        @return const reference to the JSON value pointed to by the JSON
+                pointer
+        */
+        const_reference get_unchecked(const_pointer ptr) const
+        {
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (ptr->m_type)
+                {
+                    case value_t::object:
+                    {
+                        // use unchecked object access
+                        ptr = &ptr->operator[](reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        if (reference_token == "-")
+                        {
+                            // "-" cannot be used for const access
+                            throw std::out_of_range("array index '-' (" +
+                                                    std::to_string(ptr->m_value.array->size()) +
+                                                    ") is out of range");
+                        }
+
+                        // error condition (cf. RFC 6901, Sect. 4)
+                        if (reference_token.size() > 1 and reference_token[0] == '0')
+                        {
+                            throw std::domain_error("array index must not begin with '0'");
+                        }
+
+                        // use unchecked array access
+                        ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        break;
+                    }
+
+                    default:
+                    {
+                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                    }
+                }
+            }
+
+            return *ptr;
+        }
+
+        const_reference get_checked(const_pointer ptr) const
+        {
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (ptr->m_type)
+                {
+                    case value_t::object:
+                    {
+                        // note: at performs range check
+                        ptr = &ptr->at(reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        if (reference_token == "-")
+                        {
+                            // "-" always fails the range check
+                            throw std::out_of_range("array index '-' (" +
+                                                    std::to_string(ptr->m_value.array->size()) +
+                                                    ") is out of range");
+                        }
+
+                        // error condition (cf. RFC 6901, Sect. 4)
+                        if (reference_token.size() > 1 and reference_token[0] == '0')
+                        {
+                            throw std::domain_error("array index must not begin with '0'");
+                        }
+
+                        // note: at performs range check
+                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
+                        break;
+                    }
+
+                    default:
+                    {
+                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                    }
+                }
+            }
+
+            return *ptr;
+        }
+
+        /// split the string input to reference tokens
+        static std::vector<std::string> split(std::string reference_string)
+        {
+            std::vector<std::string> result;
+
+            // special case: empty reference string -> no reference tokens
+            if (reference_string.empty())
+            {
+                return result;
+            }
+
+            // check if nonempty reference string begins with slash
+            if (reference_string[0] != '/')
+            {
+                throw std::domain_error("JSON pointer must be empty or begin with '/'");
+            }
+
+            // extract the reference tokens:
+            // - slash: position of the last read slash (or end of string)
+            // - start: position after the previous slash
+            for (
+                // search for the first slash after the first character
+                size_t slash = reference_string.find_first_of("/", 1),
+                // set the beginning of the first reference token
+                start = 1;
+                // we can stop if start == string::npos+1 = 0
+                start != 0;
+                // set the beginning of the next reference token
+                // (will eventually be 0 if slash == std::string::npos)
+                start = slash + 1,
+                // find next slash
+                slash = reference_string.find_first_of("/", start))
+            {
+                // use the text between the beginning of the reference token
+                // (start) and the last slash (slash).
+                auto reference_token = reference_string.substr(start, slash - start);
+
+                // check reference tokens are properly escaped
+                for (size_t pos = reference_token.find_first_of("~");
+                        pos != std::string::npos;
+                        pos = reference_token.find_first_of("~", pos + 1))
+                {
+                    assert(reference_token[pos] == '~');
+
+                    // ~ must be followed by 0 or 1
+                    if (pos == reference_token.size() - 1 or
+                            (reference_token[pos + 1] != '0' and
+                             reference_token[pos + 1] != '1'))
+                    {
+                        throw std::domain_error("escape error: '~' must be followed with '0' or '1'");
+                    }
+                }
+
+                // finally, store the reference token
+                unescape(reference_token);
+                result.push_back(reference_token);
+            }
+
+            return result;
+        }
+
+      private:
+        /*!
+        @brief replace all occurrences of a substring by another string
+
+        @param[in,out] s  the string to manipulate
+        @param[in]     f  the substring to replace with @a t
+        @param[in]     t  the string to replace @a f
+
+        @return The string @a s where all occurrences of @a f are replaced
+                with @a t.
+
+        @pre The search string @a f must not be empty.
+
+        @since version 2.0.0
+        */
+        static void replace_substring(std::string& s,
+                                      const std::string& f,
+                                      const std::string& t)
+        {
+            assert(not f.empty());
+
+            for (
+                size_t pos = s.find(f);         // find first occurrence of f
+                pos != std::string::npos;       // make sure f was found
+                s.replace(pos, f.size(), t),    // replace with t
+                pos = s.find(f, pos + t.size()) // find next occurrence of f
+            );
+        }
+
+        /// escape tilde and slash
+        static std::string escape(std::string s)
+        {
+            // escape "~"" to "~0" and "/" to "~1"
+            replace_substring(s, "~", "~0");
+            replace_substring(s, "/", "~1");
+            return s;
+        }
+
+        /// unescape tilde and slash
+        static void unescape(std::string& s)
+        {
+            // first transform any occurrence of the sequence '~1' to '/'
+            replace_substring(s, "~1", "/");
+            // then transform any occurrence of the sequence '~0' to '~'
+            replace_substring(s, "~0", "~");
+        }
+
+        /*!
+        @param[in] reference_string  the reference string to the current value
+        @param[in] value             the value to consider
+        @param[in,out] result        the result object to insert values to
+
+        @note Empty objects or arrays are flattened to `null`.
+        */
+        static void flatten(const std::string& reference_string,
+                            const basic_json& value,
+                            basic_json& result)
+        {
+            switch (value.m_type)
+            {
+                case value_t::array:
+                {
+                    if (value.m_value.array->empty())
+                    {
+                        // flatten empty array as null
+                        result[reference_string] = nullptr;
+                    }
+                    else
+                    {
+                        // iterate array and use index as reference string
+                        for (size_t i = 0; i < value.m_value.array->size(); ++i)
+                        {
+                            flatten(reference_string + "/" + std::to_string(i),
+                                    value.m_value.array->operator[](i), result);
+                        }
+                    }
+                    break;
+                }
+
+                case value_t::object:
+                {
+                    if (value.m_value.object->empty())
+                    {
+                        // flatten empty object as null
+                        result[reference_string] = nullptr;
+                    }
+                    else
+                    {
+                        // iterate object and use keys as reference string
+                        for (const auto& element : *value.m_value.object)
+                        {
+                            flatten(reference_string + "/" + escape(element.first),
+                                    element.second, result);
+                        }
+                    }
+                    break;
+                }
+
+                default:
+                {
+                    // add primitive value with its reference string
+                    result[reference_string] = value;
+                    break;
+                }
+            }
+        }
+
+        /*!
+        @param[in] value  flattened JSON
+
+        @return unflattened JSON
+        */
+        static basic_json unflatten(const basic_json& value)
+        {
+            if (not value.is_object())
+            {
+                throw std::domain_error("only objects can be unflattened");
+            }
+
+            basic_json result;
+
+            // iterate the JSON object values
+            for (const auto& element : *value.m_value.object)
+            {
+                if (not element.second.is_primitive())
+                {
+                    throw std::domain_error("values in object must be primitive");
+                }
+
+                // assign value to reference pointed to by JSON pointer; Note
+                // that if the JSON pointer is "" (i.e., points to the whole
+                // value), function get_and_create returns a reference to
+                // result itself. An assignment will then create a primitive
+                // value.
+                json_pointer(element.first).get_and_create(result) = element.second;
+            }
+
+            return result;
+        }
+
+      private:
+        /// the reference tokens
+        std::vector<std::string> reference_tokens {};
+    };
+
+    //////////////////////////
+    // JSON Pointer support //
+    //////////////////////////
+
+    /// @name JSON Pointer functions
+    /// @{
+
+    /*!
+    @brief access specified element via JSON Pointer
+
+    Uses a JSON pointer to retrieve a reference to the respective JSON value.
+    No bound checking is performed. Similar to @ref operator[](const typename
+    object_t::key_type&), `null` values are created in arrays and objects if
+    necessary.
+
+    In particular:
+    - If the JSON pointer points to an object key that does not exist, it
+      is created an filled with a `null` value before a reference to it
+      is returned.
+    - If the JSON pointer points to an array index that does not exist, it
+      is created an filled with a `null` value before a reference to it
+      is returned. All indices between the current maximum and the given
+      index are also filled with `null`.
+    - The special value `-` is treated as a synonym for the index past the
+      end.
+
+    @param[in] ptr  a JSON pointer
+
+    @return reference to the element pointed to by @a ptr
+
+    @complexity Constant.
+
+    @throw std::out_of_range      if the JSON pointer can not be resolved
+    @throw std::domain_error      if an array index begins with '0'
+    @throw std::invalid_argument  if an array index was not a number
+
+    @liveexample{The behavior is shown in the example.,operatorjson_pointer}
+
+    @since version 2.0.0
+    */
+    reference operator[](const json_pointer& ptr)
+    {
+        return ptr.get_unchecked(this);
+    }
+
+    /*!
+    @brief access specified element via JSON Pointer
+
+    Uses a JSON pointer to retrieve a reference to the respective JSON value.
+    No bound checking is performed. The function does not change the JSON
+    value; no `null` values are created. In particular, the the special value
+    `-` yields an exception.
+
+    @param[in] ptr  JSON pointer to the desired element
+
+    @return const reference to the element pointed to by @a ptr
+
+    @complexity Constant.
+
+    @throw std::out_of_range      if the JSON pointer can not be resolved
+    @throw std::domain_error      if an array index begins with '0'
+    @throw std::invalid_argument  if an array index was not a number
+
+    @liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
+
+    @since version 2.0.0
+    */
+    const_reference operator[](const json_pointer& ptr) const
+    {
+        return ptr.get_unchecked(this);
+    }
+
+    /*!
+    @brief access specified element via JSON Pointer
+
+    Returns a reference to the element at with specified JSON pointer @a ptr,
+    with bounds checking.
+
+    @param[in] ptr  JSON pointer to the desired element
+
+    @return reference to the element pointed to by @a ptr
+
+    @complexity Constant.
+
+    @throw std::out_of_range      if the JSON pointer can not be resolved
+    @throw std::domain_error      if an array index begins with '0'
+    @throw std::invalid_argument  if an array index was not a number
+
+    @liveexample{The behavior is shown in the example.,at_json_pointer}
+
+    @since version 2.0.0
+    */
+    reference at(const json_pointer& ptr)
+    {
+        return ptr.get_checked(this);
+    }
+
+    /*!
+    @brief access specified element via JSON Pointer
+
+    Returns a const reference to the element at with specified JSON pointer @a
+    ptr, with bounds checking.
+
+    @param[in] ptr  JSON pointer to the desired element
+
+    @return reference to the element pointed to by @a ptr
+
+    @complexity Constant.
+
+    @throw std::out_of_range      if the JSON pointer can not be resolved
+    @throw std::domain_error      if an array index begins with '0'
+    @throw std::invalid_argument  if an array index was not a number
+
+    @liveexample{The behavior is shown in the example.,at_json_pointer_const}
+
+    @since version 2.0.0
+    */
+    const_reference at(const json_pointer& ptr) const
+    {
+        return ptr.get_checked(this);
+    }
+
+    /*!
+    @brief return flattened JSON value
+
+    The function creates a JSON object whose keys are JSON pointers (see [RFC
+    6901](https://tools.ietf.org/html/rfc6901)) and whose values are all
+    primitive. The original JSON value can be restored using the @ref
+    unflatten() function.
+
+    @return an object that maps JSON pointers to primitve values
+
+    @note Empty objects and arrays are flattened to `null` and will not be
+          reconstructed correctly by the @ref unflatten() function.
+
+    @complexity Linear in the size the JSON value.
+
+    @liveexample{The following code shows how a JSON object is flattened to an
+    object whose keys consist of JSON pointers.,flatten}
+
+    @sa @ref unflatten() for the reverse function
+
+    @since version 2.0.0
+    */
+    basic_json flatten() const
+    {
+        basic_json result(value_t::object);
+        json_pointer::flatten("", *this, result);
+        return result;
+    }
+
+    /*!
+    @brief unflatten a previously flattened JSON value
+
+    The function restores the arbitrary nesting of a JSON value that has been
+    flattened before using the @ref flatten() function. The JSON value must
+    meet certain constraints:
+    1. The value must be an object.
+    2. The keys must be JSON pointers (see
+       [RFC 6901](https://tools.ietf.org/html/rfc6901))
+    3. The mapped values must be primitive JSON types.
+
+    @return the original JSON from a flattened version
+
+    @note Empty objects and arrays are flattened by @ref flatten() to `null`
+          values and can not unflattened to their original type. Apart from
+          this example, for a JSON value `j`, the following is always true:
+          `j == j.flatten().unflatten()`.
+
+    @complexity Linear in the size the JSON value.
+
+    @liveexample{The following code shows how a flattened JSON object is
+    unflattened into the original nested JSON object.,unflatten}
+
+    @sa @ref flatten() for the reverse function
+
+    @since version 2.0.0
+    */
+    basic_json unflatten() const
+    {
+        return json_pointer::unflatten(*this);
+    }
+
+    /// @}
+
+    //////////////////////////
+    // JSON Patch functions //
+    //////////////////////////
+
+    /// @name JSON Patch functions
+    /// @{
+
+    /*!
+    @brief applies a JSON patch
+
+    [JSON Patch](http://jsonpatch.com) defines a JSON document structure for
+    expressing a sequence of operations to apply to a JSON) document. With
+    this funcion, a JSON Patch is applied to the current JSON value by
+    executing all operations from the patch.
+
+    @param[in] json_patch  JSON patch document
+    @return patched document
+
+    @note The application of a patch is atomic: Either all operations succeed
+          and the patched document is returned or an exception is thrown. In
+          any case, the original value is not changed: the patch is applied
+          to a copy of the value.
+
+    @throw std::out_of_range if a JSON pointer inside the patch could not
+    be resolved successfully in the current JSON value; example: `"key baz
+    not found"`
+    @throw invalid_argument if the JSON patch is malformed (e.g., mandatory
+    attributes are missing); example: `"operation add must have member path"`
+
+    @complexity Linear in the size of the JSON value and the length of the
+    JSON patch. As usually only a fraction of the JSON value is affected by
+    the patch, the complexity can usually be neglected.
+
+    @liveexample{The following code shows how a JSON patch is applied to a
+    value.,patch}
+
+    @sa @ref diff -- create a JSON patch by comparing two JSON values
+
+    @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
+    @sa [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
+
+    @since version 2.0.0
+    */
+    basic_json patch(const basic_json& json_patch) const
+    {
+        // make a working copy to apply the patch to
+        basic_json result = *this;
+
+        // the valid JSON Patch operations
+        enum class patch_operations {add, remove, replace, move, copy, test, invalid};
+
+        const auto get_op = [](const std::string op)
+        {
+            if (op == "add")
+            {
+                return patch_operations::add;
+            }
+            if (op == "remove")
+            {
+                return patch_operations::remove;
+            }
+            if (op == "replace")
+            {
+                return patch_operations::replace;
+            }
+            if (op == "move")
+            {
+                return patch_operations::move;
+            }
+            if (op == "copy")
+            {
+                return patch_operations::copy;
+            }
+            if (op == "test")
+            {
+                return patch_operations::test;
+            }
+
+            return patch_operations::invalid;
+        };
+
+        // wrapper for "add" operation; add value at ptr
+        const auto operation_add = [&result](json_pointer & ptr, basic_json val)
+        {
+            // adding to the root of the target document means replacing it
+            if (ptr.is_root())
+            {
+                result = val;
+            }
+            else
+            {
+                // make sure the top element of the pointer exists
+                json_pointer top_pointer = ptr.top();
+                if (top_pointer != ptr)
+                {
+                    basic_json& x = result.at(top_pointer);
+                }
+
+                // get reference to parent of JSON pointer ptr
+                const auto last_path = ptr.pop_back();
+                basic_json& parent = result[ptr];
+
+                switch (parent.m_type)
+                {
+                    case value_t::null:
+                    case value_t::object:
+                    {
+                        // use operator[] to add value
+                        parent[last_path] = val;
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        if (last_path == "-")
+                        {
+                            // special case: append to back
+                            parent.push_back(val);
+                        }
+                        else
+                        {
+                            const auto idx = std::stoi(last_path);
+                            if (static_cast<size_type>(idx) > parent.size())
+                            {
+                                // avoid undefined behavior
+                                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+                            }
+                            else
+                            {
+                                // default case: insert add offset
+                                parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
+                            }
+                        }
+                        break;
+                    }
+
+                    default:
+                    {
+                        // if there exists a parent it cannot be primitive
+                        assert(false);  // LCOV_EXCL_LINE
+                    }
+                }
+            }
+        };
+
+        // wrapper for "remove" operation; remove value at ptr
+        const auto operation_remove = [&result](json_pointer & ptr)
+        {
+            // get reference to parent of JSON pointer ptr
+            const auto last_path = ptr.pop_back();
+            basic_json& parent = result.at(ptr);
+
+            // remove child
+            if (parent.is_object())
+            {
+                // perform range check
+                auto it = parent.find(last_path);
+                if (it != parent.end())
+                {
+                    parent.erase(it);
+                }
+                else
+                {
+                    throw std::out_of_range("key '" + last_path + "' not found");
+                }
+            }
+            else if (parent.is_array())
+            {
+                // note erase performs range check
+                parent.erase(static_cast<size_type>(std::stoi(last_path)));
+            }
+        };
+
+        // type check
+        if (not json_patch.is_array())
+        {
+            // a JSON patch must be an array of objects
+            throw std::invalid_argument("JSON patch must be an array of objects");
+        }
+
+        // iterate and apply th eoperations
+        for (const auto& val : json_patch)
+        {
+            // wrapper to get a value for an operation
+            const auto get_value = [&val](const std::string & op,
+                                          const std::string & member,
+                                          bool string_type) -> basic_json&
+            {
+                // find value
+                auto it = val.m_value.object->find(member);
+
+                // context-sensitive error message
+                const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";
+
+                // check if desired value is present
+                if (it == val.m_value.object->end())
+                {
+                    throw std::invalid_argument(error_msg + " must have member '" + member + "'");
+                }
+
+                // check if result is of type string
+                if (string_type and not it->second.is_string())
+                {
+                    throw std::invalid_argument(error_msg + " must have string member '" + member + "'");
+                }
+
+                // no error: return value
+                return it->second;
+            };
+
+            // type check
+            if (not val.is_object())
+            {
+                throw std::invalid_argument("JSON patch must be an array of objects");
+            }
+
+            // collect mandatory members
+            const std::string op = get_value("op", "op", true);
+            const std::string path = get_value(op, "path", true);
+            json_pointer ptr(path);
+
+            switch (get_op(op))
+            {
+                case patch_operations::add:
+                {
+                    operation_add(ptr, get_value("add", "value", false));
+                    break;
+                }
+
+                case patch_operations::remove:
+                {
+                    operation_remove(ptr);
+                    break;
+                }
+
+                case patch_operations::replace:
+                {
+                    // the "path" location must exist - use at()
+                    result.at(ptr) = get_value("replace", "value", false);
+                    break;
+                }
+
+                case patch_operations::move:
+                {
+                    const std::string from_path = get_value("move", "from", true);
+                    json_pointer from_ptr(from_path);
+
+                    // the "from" location must exist - use at()
+                    basic_json v = result.at(from_ptr);
+
+                    // The move operation is functionally identical to a
+                    // "remove" operation on the "from" location, followed
+                    // immediately by an "add" operation at the target
+                    // location with the value that was just removed.
+                    operation_remove(from_ptr);
+                    operation_add(ptr, v);
+                    break;
+                }
+
+                case patch_operations::copy:
+                {
+                    const std::string from_path = get_value("copy", "from", true);;
+                    const json_pointer from_ptr(from_path);
+
+                    // the "from" location must exist - use at()
+                    result[ptr] = result.at(from_ptr);
+                    break;
+                }
+
+                case patch_operations::test:
+                {
+                    bool success = false;
+                    try
+                    {
+                        // check if "value" matches the one at "path"
+                        // the "path" location must exist - use at()
+                        success = (result.at(ptr) == get_value("test", "value", false));
+                    }
+                    catch (std::out_of_range&)
+                    {
+                        // ignore out of range errors: success remains false
+                    }
+
+                    // throw an exception if test fails
+                    if (not success)
+                    {
+                        throw std::domain_error("unsuccessful: " + val.dump());
+                    }
+
+                    break;
+                }
+
+                case patch_operations::invalid:
+                {
+                    // op must be "add", "remove", "replace", "move", "copy", or
+                    // "test"
+                    throw std::invalid_argument("operation value '" + op + "' is invalid");
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief creates a diff as a JSON patch
+
+    Creates a [JSON Patch](http://jsonpatch.com) so that value @a source can
+    be changed into the value @a target by calling @ref patch function.
+
+    @invariant For two JSON values @a source and @a target, the following code
+    yields always `true`:
+    @code {.cpp}
+    source.patch(diff(source, target)) == target;
+    @endcode
+
+    @note Currently, only `remove`, `add`, and `replace` operations are
+          generated.
+
+    @param[in] source  JSON value to copare from
+    @param[in] target  JSON value to copare against
+    @param[in] path    helper value to create JSON pointers
+
+    @return a JSON patch to convert the @a source to @a target
+
+    @complexity Linear in the lengths of @a source and @a target.
+
+    @liveexample{The following code shows how a JSON patch is created as a
+    diff for two JSON values.,diff}
+
+    @sa @ref patch -- apply a JSON patch
+
+    @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
+
+    @since version 2.0.0
+    */
+    static basic_json diff(const basic_json& source,
+                           const basic_json& target,
+                           std::string path = "")
+    {
+        // the patch
+        basic_json result(value_t::array);
+
+        // if the values are the same, return empty patch
+        if (source == target)
+        {
+            return result;
+        }
+
+        if (source.type() != target.type())
+        {
+            // different types: replace value
+            result.push_back(
+            {
+                {"op", "replace"},
+                {"path", path},
+                {"value", target}
+            });
+        }
+        else
+        {
+            switch (source.type())
+            {
+                case value_t::array:
+                {
+                    // first pass: traverse common elements
+                    size_t i = 0;
+                    while (i < source.size() and i < target.size())
+                    {
+                        // recursive call to compare array values at index i
+                        auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
+                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
+                        ++i;
+                    }
+
+                    // i now reached the end of at least one array
+                    // in a second pass, traverse the remaining elements
+
+                    // remove my remaining elements
+                    const auto end_index = static_cast<difference_type>(result.size());
+                    while (i < source.size())
+                    {
+                        // add operations in reverse order to avoid invalid
+                        // indices
+                        result.insert(result.begin() + end_index, object(
+                        {
+                            {"op", "remove"},
+                            {"path", path + "/" + std::to_string(i)}
+                        }));
+                        ++i;
+                    }
+
+                    // add other remaining elements
+                    while (i < target.size())
+                    {
+                        result.push_back(
+                        {
+                            {"op", "add"},
+                            {"path", path + "/" + std::to_string(i)},
+                            {"value", target[i]}
+                        });
+                        ++i;
+                    }
+
+                    break;
+                }
+
+                case value_t::object:
+                {
+                    // first pass: traverse this object's elements
+                    for (auto it = source.begin(); it != source.end(); ++it)
+                    {
+                        // escape the key name to be used in a JSON patch
+                        const auto key = json_pointer::escape(it.key());
+
+                        if (target.find(it.key()) != target.end())
+                        {
+                            // recursive call to compare object values at key it
+                            auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key);
+                            result.insert(result.end(), temp_diff.begin(), temp_diff.end());
+                        }
+                        else
+                        {
+                            // found a key that is not in o -> remove it
+                            result.push_back(object(
+                            {
+                                {"op", "remove"},
+                                {"path", path + "/" + key}
+                            }));
+                        }
+                    }
+
+                    // second pass: traverse other object's elements
+                    for (auto it = target.begin(); it != target.end(); ++it)
+                    {
+                        if (source.find(it.key()) == source.end())
+                        {
+                            // found a key that is not in this -> add it
+                            const auto key = json_pointer::escape(it.key());
+                            result.push_back(
+                            {
+                                {"op", "add"},
+                                {"path", path + "/" + key},
+                                {"value", it.value()}
+                            });
+                        }
+                    }
+
+                    break;
+                }
+
+                default:
+                {
+                    // both primitive type: replace value
+                    result.push_back(
+                    {
+                        {"op", "replace"},
+                        {"path", path},
+                        {"value", target}
+                    });
+                    break;
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /// @}
+};
+
+
+/////////////
+// presets //
+/////////////
+
+/*!
+@brief default JSON class
+
+This type is the default specialization of the @ref basic_json class which
+uses the standard template types.
+
+@since version 1.0.0
+*/
+using json = basic_json<>;
+}
+
+
+///////////////////////
+// nonmember support //
+///////////////////////
+
+// specialization of std::swap, and std::hash
+namespace std
+{
+/*!
+@brief exchanges the values of two JSON objects
+
+@since version 1.0.0
+*/
+template <>
+inline void swap(nlohmann::json& j1,
+                 nlohmann::json& j2) noexcept(
+                     is_nothrow_move_constructible<nlohmann::json>::value and
+                     is_nothrow_move_assignable<nlohmann::json>::value
+                 )
+{
+    j1.swap(j2);
+}
+
+/// hash value for JSON objects
+template <>
+struct hash<nlohmann::json>
+{
+    /*!
+    @brief return a hash value for a JSON object
+
+    @since version 1.0.0
+    */
+    std::size_t operator()(const nlohmann::json& j) const
+    {
+        // a naive hashing via the string representation
+        const auto& h = hash<nlohmann::json::string_t>();
+        return h(j.dump());
+    }
+};
+}
+
+/*!
+@brief user-defined string literal for JSON values
+
+This operator implements a user-defined string literal for JSON objects. It
+can be used by adding `"_json"` to a string literal and returns a JSON object
+if no parse error occurred.
+
+@param[in] s  a string representation of a JSON object
+@return a JSON object
+
+@since version 1.0.0
+*/
+inline nlohmann::json operator "" _json(const char* s, std::size_t)
+{
+    return nlohmann::json::parse(reinterpret_cast<const nlohmann::json::string_t::value_type*>(s));
+}
+
+/*!
+@brief user-defined string literal for JSON pointer
+
+This operator implements a user-defined string literal for JSON Pointers. It
+can be used by adding `"_json"` to a string literal and returns a JSON pointer
+object if no parse error occurred.
+
+@param[in] s  a string representation of a JSON Pointer
+@return a JSON pointer object
+
+@since version 2.0.0
+*/
+inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t)
+{
+    return nlohmann::json::json_pointer(s);
+}
+
+// restore GCC/clang diagnostic settings
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #pragma GCC diagnostic pop
+#endif
+
+#endif
diff --git a/ext/offbase/offbase.hpp b/ext/offbase/offbase.hpp
new file mode 100644
index 00000000..acce8c4a
--- /dev/null
+++ b/ext/offbase/offbase.hpp
@@ -0,0 +1,393 @@
+/*
+ * Offbase: a super-minimal in-filesystem JSON object persistence store
+ */
+
+#ifndef OFFBASE_HPP__
+#define OFFBASE_HPP__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <dirent.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include <vector>
+#include <string>
+#include <map>
+
+#include "json/json.hpp"
+
+#define OFFBASE_PATH_SEP "/"
+
+/**
+ * A super-minimal in-filesystem JSON object persistence store
+ */
+class offbase : public nlohmann::json
+{
+public:
+	offbase(const char *p) :
+		nlohmann::json(nlohmann::json::object()),
+		_path(p),
+		_saved(nlohmann::json::object())
+	{
+		this->load();
+	}
+
+	~offbase()
+	{
+		this->commit();
+	}
+
+	/**
+	 * Load this instance from disk, clearing any existing contents first
+	 *
+	 * If the 'errors' vector is NULL, false is returned and reading aborts
+	 * on any error. If this parameter is non-NULL the paths of errors will
+	 * be added to the vector and reading will continue. False will only be
+	 * returned on really big errors like no path being defined.
+	 *
+	 * @param errors If specified, fill this vector with the paths to any objects that fail read
+	 * @return True on success, false on fatal error
+	 */
+	inline bool load(std::vector<std::string> *errors = (std::vector<std::string> *)0)
+	{
+		if (!_path.length())
+			return false;
+		*this = nlohmann::json::object();
+		if (!_loadObj(_path,*this,errors))
+			return false;
+		_saved = *(reinterpret_cast<nlohmann::json *>(this));
+		return true;
+	}
+
+	/**
+	 * Commit any pending changes to this object to disk
+	 *
+	 * @return True on success or false if an I/O error occurred
+	 */
+	inline bool commit(std::vector<std::string> *errors = (std::vector<std::string> *)0)
+	{
+		if (!_path.length())
+			return false;
+		if (!_commitObj(_path,*this,&_saved,errors))
+			return false;
+		_saved = *(reinterpret_cast<nlohmann::json *>(this));
+		return true;
+	}
+
+	static inline std::string escapeKey(const std::string &k)
+	{
+		std::string e;
+		const char *ptr = k.data();
+		const char *eof = ptr + k.length();
+		char tmp[8];
+		while (ptr != eof) {
+			if ( ((*ptr >= 'a')&&(*ptr <= 'z')) || ((*ptr >= 'A')&&(*ptr <= 'Z')) || ((*ptr >= '0')&&(*ptr <= '9')) || (*ptr == '.') || (*ptr == '_') || (*ptr == '-') || (*ptr == ',') )
+				e.push_back(*ptr);
+			else {
+				snprintf(tmp,sizeof(tmp),"~%.2x",(unsigned int)*ptr);
+				e.append(tmp);
+			}
+			++ptr;
+		}
+		return e;
+	}
+
+	static inline std::string unescapeKey(const std::string &k)
+	{
+		std::string u;
+		const char *ptr = k.data();
+		const char *eof = ptr + k.length();
+		char tmp[8];
+		while (ptr != eof) {
+			if (*ptr == '~') {
+				if (++ptr == eof) break;
+				tmp[0] = *ptr;
+				if (++ptr == eof) break;
+				tmp[1] = *(ptr++);
+				tmp[2] = (char)0;
+				u.push_back((char)strtol(tmp,(char **)0,16));
+			} else {
+				u.push_back(*(ptr++));
+			}
+		}
+		return u;
+	}
+
+private:
+	static inline bool _readFile(const char *path,std::string &buf)
+	{
+		char tmp[4096];
+		FILE *f = fopen(path,"rb");
+		if (f) {
+			for(;;) {
+				long n = (long)fread(tmp,1,sizeof(tmp),f);
+				if (n > 0)
+					buf.append(tmp,n);
+				else break;
+			}
+			fclose(f);
+			return true;
+		}
+		return false;
+	}
+
+	static inline bool _loadArr(const std::string &path,nlohmann::json &arr,std::vector<std::string> *errors)
+	{
+		std::map<unsigned long,nlohmann::json> atmp; // place into an ordered container first because filesystem does not guarantee this
+
+		struct dirent dbuf;
+		struct dirent *de;
+		DIR *d = opendir(path.c_str());
+		if (d) {
+			while (!readdir_d(d,&dbuf,&de)) {
+				if (!de) break;
+				const std::string name(de->d_name);
+				if (name.length() != 12) continue; // array entries are XXXXXXXXXX.T
+				if (name[name.length()-2] == '.') {
+					if (name[name.length()-1] == 'V') {
+						std::string buf;
+						if (_readFile((path + OFFBASE_PATH_SEP + name).c_str(),buf)) {
+							try {
+								atmp[strtoul(name.substr(0,10).c_str(),(char **)0,16)] = nlohmann::json::parse(buf);
+							} catch ( ... ) {
+								if (errors) {
+									errors->push_back(path + OFFBASE_PATH_SEP + name);
+								} else {
+									return false;
+								}
+							}
+						} else if (errors) {
+							errors->push_back(path + OFFBASE_PATH_SEP + name);
+						} else return false;
+					} else if (name[name.length()-1] == 'O') {
+						if (!_loadObj(path + OFFBASE_PATH_SEP + name,atmp[strtoul(name.substr(0,10).c_str(),(char **)0,16)] = nlohmann::json::object(),errors))
+							return false;
+					} else if (name[name.length()-1] == 'A') {
+						if (!_loadArr(path + OFFBASE_PATH_SEP + name,atmp[strtoul(name.substr(0,10).c_str(),(char **)0,16)] = nlohmann::json::array(),errors))
+							return false;
+					}
+				}
+			}
+			closedir(d);
+		} else if (errors) {
+			errors->push_back(path);
+		} else return false;
+
+		if (atmp.size() > 0) {
+			unsigned long lasti = 0;
+			for(std::map<unsigned long,nlohmann::json>::iterator i(atmp.begin());i!=atmp.end();++i) {
+				for(unsigned long k=lasti;k<i->first;++k) // fill any gaps with nulls
+					arr.push_back(nlohmann::json(std::nullptr_t));
+				lasti = i->first;
+				arr.push_back(i->second);
+			}
+		}
+
+		return true;
+	}
+
+	static inline bool _loadObj(const std::string &path,nlohmann::json &obj,std::vector<std::string> *errors)
+	{
+		struct dirent dbuf;
+		struct dirent *de;
+		DIR *d = opendir(path.c_str());
+		if (d) {
+			while (!readdir_d(d,&dbuf,&de)) {
+				if (!de) break;
+				if ((strcmp(de->d_name,".") == 0)||(strcmp(de->d_name,"..") == 0)) continue; // sanity check
+				const std::string name(de->d_name);
+				if (name.length() <= 2) continue;
+				if (name[name.length()-2] == '.') {
+					if (name[name.length()-1] == 'V') {
+						std::string buf;
+						if (_readFile((path + OFFBASE_PATH_SEP + name).c_str(),buf)) {
+							try {
+								obj[unescapeKey(name)] = nlohmann::json::parse(buf);
+							} catch ( ... ) {
+								if (errors) {
+									errors->push_back(path + OFFBASE_PATH_SEP + name);
+								} else {
+									return false;
+								}
+							}
+						} else if (errors) {
+							errors->push_back(path + OFFBASE_PATH_SEP + name);
+						} else return false;
+					} else if (name[name.length()-1] == 'O') {
+						if (!_loadObj(path + OFFBASE_PATH_SEP + name,obj[unescapeKey(name)] = nlohmann::json::object(),errors))
+							return false;
+					} else if (name[name.length()-1] == 'A') {
+						if (!_loadArr(path + OFFBASE_PATH_SEP + name,obj[unescapeKey(name)] = nlohmann::json::array(),errors))
+							return false;
+					}
+				}
+			}
+			closedir(d);
+		} else if (errors) {
+			errors->push_back(path);
+		} else return false;
+		return true;
+	}
+
+	static inline void _rmDashRf(const std::string &path)
+	{
+		struct dirent dbuf;
+		struct dirent *de;
+		DIR *d = opendir(path.c_str());
+		if (d) {
+			while (!readdir_r(d,&dbuf,&de)) {
+				if (!de) break;
+				if ((strcmp(de->d_name,".") == 0)||(strcmp(de->d_name,"..") == 0)) continue; // sanity check
+				const std::string full(path + OFFBASE_PATH_SEP + de->d_name);
+				if (unlink(full.c_str())) {
+					_rmDashRf(full);
+					rmdir(full.c_str());
+				}
+			}
+			closedir(d);
+		}
+		rmdir(path.c_str());
+	}
+
+	static inline bool _commitArr(const std::string &path,const nlohmann::json &arr,const nlohmann::json *previous,std::vector<std::string> *errors)
+	{
+		char tmp[32];
+
+		if (!arr.is_array())
+			return false;
+
+		mkdir(path.c_str(),0755);
+
+		for(unsigned long i=0;i<(unsigned long)arr.size();++i) {
+			const nlohmann::json &value = arr[i];
+
+			const nlohmann::json *next = (const nlohmann::json *)0;
+			if ((previous)&&(previous->is_array())&&(i < previous->size())) {
+				next = &((*previous)[i]);
+				if (*next == value)
+					continue;
+			}
+
+			if (value.is_object()) {
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.O",OFFBASE_PATH_SEP,i);
+				if (!_commitObj(path + tmp,value,next,errors))
+					return false;
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.V",OFFBASE_PATH_SEP,i);
+				unlink((path + tmp).c_str());
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.A",OFFBASE_PATH_SEP,i);
+				_rmDashRf(path + tmp);
+			} else if (value.is_array()) {
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.A",OFFBASE_PATH_SEP,i);
+				if (!_commitArr(path + tmp,value,next,errors))
+					return false;
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.O",OFFBASE_PATH_SEP,i);
+				_rmDashRf(path + tmp);
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.V",OFFBASE_PATH_SEP,i);
+				unlink((path + tmp).c_str());
+			} else {
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.V",OFFBASE_PATH_SEP,i);
+				FILE *f = fopen((path + tmp).c_str(),"w");
+				if (f) {
+					const std::string v(value.dump());
+					if (fwrite(v.c_str(),v.length(),1,f) != 1) {
+						fclose(f);
+						return false;
+					} else {
+						fclose(f);
+					}
+				} else {
+					return false;
+				}
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.A",OFFBASE_PATH_SEP,i);
+				_rmDashRf(path + tmp);
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.O",OFFBASE_PATH_SEP,i);
+				_rmDashRf(path + tmp);
+			}
+		}
+
+		if ((previous)&&(previous->is_array())) {
+			for(unsigned long i=(unsigned long)arr.size();i<(unsigned long)previous->size();++i) {
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.V",OFFBASE_PATH_SEP,i);
+				unlink((path + tmp).c_str());
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.A",OFFBASE_PATH_SEP,i);
+				_rmDashRf(path + tmp);
+				snprintf(tmp,sizeof(tmp),"%s%.10lx.O",OFFBASE_PATH_SEP,i);
+				_rmDashRf(path + tmp);
+			}
+		}
+
+		return true;
+	}
+
+	static inline bool _commitObj(const std::string &path,const nlohmann::json &obj,const nlohmann::json *previous,std::vector<std::string> *errors)
+	{
+		if (!obj.is_object())
+			return false;
+
+		mkdir(path.c_str(),0755);
+
+		for(nlohmann::json::const_iterator i(obj.begin());i!=obj.end();++i) {
+			if (i.key().length() == 0)
+				continue;
+
+			const nlohmann::json *next = (const nlohmann::json *)0;
+			if ((previous)&&(previous->is_object())) {
+				nlohmann::json::const_iterator saved(previous->find(i.key()));
+				if (saved != previous->end()) {
+					next = &(saved.value());
+					if (i.value() == *next)
+						continue;
+				}
+			}
+
+			const std::string keyp(path + OFFBASE_PATH_SEP + escapeKey(i.key()));
+			if (i.value().is_object()) {
+				if (!_commitObj(keyp + ".O",i.value(),next,errors))
+					return false;
+				unlink((keyp + ".V").c_str());
+				_rmDashRf(keyp + ".A");
+			} else if (i.value().is_array()) {
+				if (!_commitArr(keyp + ".A",i.value(),next,errors))
+					return false;
+				unlink((keyp + ".V").c_str());
+				_rmDashRf(keyp + ".O");
+			} else {
+				FILE *f = fopen((keyp + ".V").c_str(),"w");
+				if (f) {
+					const std::string v(i.value().dump());
+					if (fwrite(v.c_str(),v.length(),1,f) != 1) {
+						fclose(f);
+						return false;
+					} else {
+						fclose(f);
+					}
+				} else {
+					return false;
+				}
+				_rmDashRf(keyp + ".A");
+				_rmDashRf(keyp + ".O");
+			}
+		}
+
+		if ((previous)&&(previous->is_object())) {
+			for(nlohmann::json::const_iterator i(previous->begin());i!=previous->end();++i) {
+				if ((i.key().length() > 0)&&(obj.find(i.key()) == obj.end())) {
+					const std::string keyp(path + OFFBASE_PATH_SEP + escapeKey(i.key()));
+ 					unlink((keyp + ".V").c_str());
+					_rmDashRf(keyp + ".A");
+					_rmDashRf(keyp + ".O");
+				}
+			}
+		}
+
+		return true;
+	}
+
+	std::string _path;
+	nlohmann::json _saved;
+};
+
+#endif
-- 
cgit v1.2.3


From b08ca49580c63abe79a650adbb0d14ca87a1cd24 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Tue, 16 Aug 2016 14:05:17 -0700
Subject: More controller work -- it builds!

---
 controller/SqliteNetworkController.cpp |   729 +--
 controller/SqliteNetworkController.hpp |    77 +-
 ext/json/LICENSE.MIT                   |    22 +
 ext/json/README.md                     |   511 ++
 ext/json/json.hpp                      | 10435 +++++++++++++++++++++++++++++++
 ext/offbase/README.md                  |    59 -
 ext/offbase/json/LICENSE.MIT           |    22 -
 ext/offbase/json/README.md             |   511 --
 ext/offbase/json/json.hpp              | 10435 -------------------------------
 ext/offbase/offbase.hpp                |   393 --
 make-mac.mk                            |     4 +-
 node/InetAddress.cpp                   |     2 +-
 osdep/OSUtils.cpp                      |    80 +
 osdep/OSUtils.hpp                      |    18 +-
 14 files changed, 11280 insertions(+), 12018 deletions(-)
 create mode 100644 ext/json/LICENSE.MIT
 create mode 100644 ext/json/README.md
 create mode 100644 ext/json/json.hpp
 delete mode 100644 ext/offbase/README.md
 delete mode 100644 ext/offbase/json/LICENSE.MIT
 delete mode 100644 ext/offbase/json/README.md
 delete mode 100644 ext/offbase/json/json.hpp
 delete mode 100644 ext/offbase/offbase.hpp

(limited to 'ext/json/json.hpp')

diff --git a/controller/SqliteNetworkController.cpp b/controller/SqliteNetworkController.cpp
index 16c02295..94d2e2e6 100644
--- a/controller/SqliteNetworkController.cpp
+++ b/controller/SqliteNetworkController.cpp
@@ -53,8 +53,6 @@
 #include "../node/MAC.hpp"
 #include "../node/Address.hpp"
 
-#include "../osdep/OSUtils.hpp"
-
 // offbase includes and builds upon nlohmann::json
 using json = nlohmann::json;
 
@@ -73,18 +71,15 @@ using json = nlohmann::json;
 // Min duration between requests for an address/nwid combo to prevent floods
 #define ZT_NETCONF_MIN_REQUEST_PERIOD 1000
 
-// Delay between backups in milliseconds
-//#define ZT_NETCONF_BACKUP_PERIOD 300000
-
 // Nodes are considered active if they've queried in less than this long
 #define ZT_NETCONF_NODE_ACTIVE_THRESHOLD ((ZT_NETWORK_AUTOCONF_DELAY * 2) + 5000)
 
 namespace ZeroTier {
 
-struct json::object _renderRule(ZT_VirtualNetworkRule &rule)
+static json _renderRule(ZT_VirtualNetworkRule &rule)
 {
 	char tmp[128];
-	json::object r;
+	json r = json::object();
 	r["not"] = ((rule.t & 0x80) != 0);
 	switch((rule.t) & 0x7f) {
 		case ZT_NETWORK_RULE_ACTION_DROP:
@@ -205,8 +200,10 @@ struct json::object _renderRule(ZT_VirtualNetworkRule &rule)
 	return r;
 }
 
-struct bool _parseRule(const json::object &r,ZT_VirtualNetworkRule &rule)
+static bool _parseRule(const json &r,ZT_VirtualNetworkRule &rule)
 {
+	if (r.is_object())
+		return false;
 	std::string t = r["type"];
 	memset(&rule,0,sizeof(ZT_VirtualNetworkRule));
 	if (r.value("not",false))
@@ -220,19 +217,19 @@ struct bool _parseRule(const json::object &r,ZT_VirtualNetworkRule &rule)
 		return true;
 	} else if (t == "ACTION_TEE") {
 		rule.t |= ZT_NETWORK_RULE_ACTION_TEE;
-		rule.v.zt = Utils::hexStrToU64(r.value("zt","0")) & 0xffffffffffULL;
+		rule.v.zt = Utils::hexStrToU64(r.value("zt","0").c_str()) & 0xffffffffffULL;
 		return true;
 	} else if (t == "ACTION_REDIRECT") {
 		rule.t |= ZT_NETWORK_RULE_ACTION_REDIRECT;
-		rule.v.zt = Utils::hexStrToU64(r.value("zt","0")) & 0xffffffffffULL;
+		rule.v.zt = Utils::hexStrToU64(r.value("zt","0").c_str()) & 0xffffffffffULL;
 		return true;
 	} else if (t == "MATCH_SOURCE_ZEROTIER_ADDRESS") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_SOURCE_ZEROTIER_ADDRESS;
-		rule.v.zt = Utils::hexStrToU64(r.value("zt","0")) & 0xffffffffffULL;
+		rule.v.zt = Utils::hexStrToU64(r.value("zt","0").c_str()) & 0xffffffffffULL;
 		return true;
 	} else if (t == "MATCH_DEST_ZEROTIER_ADDRESS") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_DEST_ZEROTIER_ADDRESS;
-		rule.v.zt = Utils::hexStrToU64(r.value("zt","0")) & 0xffffffffffULL;
+		rule.v.zt = Utils::hexStrToU64(r.value("zt","0").c_str()) & 0xffffffffffULL;
 		return true;
 	} else if (t == "MATCH_VLAN_ID") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_VLAN_ID;
@@ -309,48 +306,58 @@ struct bool _parseRule(const json::object &r,ZT_VirtualNetworkRule &rule)
 	} else if (t == "MATCH_CHARACTERISTICS") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_CHARACTERISTICS;
 		if (r.count("mask")) {
-			auto mask = r["mask"];
-			rule.v.characteristics[0] = (mask.is_integer() ? (uint64_t)mask : Utils::hexStrToU64(mask));
+			auto v = r["mask"];
+			if (v.is_number()) {
+				rule.v.characteristics[0] = v;
+			} else {
+				std::string tmp = v;
+				rule.v.characteristics[0] = Utils::hexStrToU64(tmp.c_str());
+			}
 		}
 		if (r.count("value")) {
-			auto value = r["value"];
-			rule.v.characteristics[1] = (value.is_integer() ? (uint64_t)value : Utils::hexStrToU64(value));
+			auto v = r["value"];
+			if (v.is_number()) {
+				rule.v.characteristics[1] = v;
+			} else {
+				std::string tmp = v;
+				rule.v.characteristics[1] = Utils::hexStrToU64(tmp.c_str());
+			}
 		}
 		return true;
 	} else if (t == "MATCH_FRAME_SIZE_RANGE") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_FRAME_SIZE_RANGE;
-		rule.v.frameSize[0] = (uint16_t)(Utils::hexStrToU64(r.value("start","0")) & 0xffffULL);
-		rule.v.frameSize[1] = (uint16_t)(Utils::hexStrToU64(r.value("end","0")) & 0xffffULL);
+		rule.v.frameSize[0] = (uint16_t)(Utils::hexStrToU64(r.value("start","0").c_str()) & 0xffffULL);
+		rule.v.frameSize[1] = (uint16_t)(Utils::hexStrToU64(r.value("end","0").c_str()) & 0xffffULL);
 		return true;
 	} else if (t == "MATCH_TAGS_SAMENESS") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_TAGS_SAMENESS;
-		rule.v.tag.id = (uint32_t)(Utils::hexStrToU64(r.value("id","0")) & 0xffffffffULL);
-		rule.v.tag.value = (uint32_t)(Utils::hexStrToU64(r.value("value","0")) & 0xffffffffULL);
+		rule.v.tag.id = (uint32_t)(Utils::hexStrToU64(r.value("id","0").c_str()) & 0xffffffffULL);
+		rule.v.tag.value = (uint32_t)(Utils::hexStrToU64(r.value("value","0").c_str()) & 0xffffffffULL);
 		return true;
 	} else if (t == "MATCH_TAGS_BITWISE_AND") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_AND;
-		rule.v.tag.id = (uint32_t)(Utils::hexStrToU64(r.value("id","0")) & 0xffffffffULL);
-		rule.v.tag.value = (uint32_t)(Utils::hexStrToU64(r.value("value","0")) & 0xffffffffULL);
+		rule.v.tag.id = (uint32_t)(Utils::hexStrToU64(r.value("id","0").c_str()) & 0xffffffffULL);
+		rule.v.tag.value = (uint32_t)(Utils::hexStrToU64(r.value("value","0").c_str()) & 0xffffffffULL);
 		return true;
 	} else if (t == "MATCH_TAGS_BITWISE_OR") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_OR;
-		rule.v.tag.id = (uint32_t)(Utils::hexStrToU64(r.value("id","0")) & 0xffffffffULL);
-		rule.v.tag.value = (uint32_t)(Utils::hexStrToU64(r.value("value","0")) & 0xffffffffULL);
+		rule.v.tag.id = (uint32_t)(Utils::hexStrToU64(r.value("id","0").c_str()) & 0xffffffffULL);
+		rule.v.tag.value = (uint32_t)(Utils::hexStrToU64(r.value("value","0").c_str()) & 0xffffffffULL);
 		return true;
 	} else if (t == "MATCH_TAGS_BITWISE_XOR") {
 		rule.t |= ZT_NETWORK_RULE_MATCH_TAGS_BITWISE_XOR;
-		rule.v.tag.id = (uint32_t)(Utils::hexStrToU64(r.value("id","0")) & 0xffffffffULL);
-		rule.v.tag.value = (uint32_t)(Utils::hexStrToU64(r.value("value","0")) & 0xffffffffULL);
+		rule.v.tag.id = (uint32_t)(Utils::hexStrToU64(r.value("id","0").c_str()) & 0xffffffffULL);
+		rule.v.tag.value = (uint32_t)(Utils::hexStrToU64(r.value("value","0").c_str()) & 0xffffffffULL);
 		return true;
 	}
 	return false;
 }
 
-SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,const char *circuitTestPath) :
+SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath) :
 	_node(node),
-	_db(dbPath),
-	_dbCommitThreadRun(true)
+	_path(dbPath)
 {
+	OSUtils::mkdir(dbPath);
 	/*
 	if (sqlite3_open_v2(dbPath,&_db,SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE,(const char *)0) != SQLITE_OK)
 		throw std::runtime_error("SqliteNetworkController cannot open database file");
@@ -592,16 +599,10 @@ SqliteNetworkController::SqliteNetworkController(Node *node,const char *dbPath,c
 
 	_backupThread = Thread::start(this);
 	*/
-
-	_dbCommitThread = Thread::start(this);
 }
 
 SqliteNetworkController::~SqliteNetworkController()
 {
-	_lock.lock();
-	_dbCommitThreadRun = false;
-	_lock.unlock();
-	Thread::join(_dbCommitThread);
 }
 
 NetworkController::ResultCode SqliteNetworkController::doNetworkConfigRequest(const InetAddress &fromAddr,const Identity &signingId,const Identity &identity,uint64_t nwid,const Dictionary<ZT_NETWORKCONFIG_METADATA_DICT_CAPACITY> &metaData,NetworkConfig &nc)
@@ -1068,7 +1069,6 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpGET(
 	std::string &responseBody,
 	std::string &responseContentType)
 {
-	Mutex::Lock _l(_lock);
 	return _doCPGet(path,urlArgs,headers,body,responseBody,responseContentType);
 }
 
@@ -1082,41 +1082,21 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 {
 	if (path.empty())
 		return 404;
-	Mutex::Lock _l(_lock);
 
 	if (path[0] == "network") {
-		json &networks = _db["network"];
-		if (!networks.is_object()) networks = json::object();
 
 		if ((path.size() >= 2)&&(path[1].length() == 16)) {
 			uint64_t nwid = Utils::hexStrToU64(path[1].c_str());
 			char nwids[24];
 			Utils::snprintf(nwids,sizeof(nwids),"%.16llx",(unsigned long long)nwid);
 
-			/*
-			int64_t revision = 0;
-			sqlite3_reset(_sGetNetworkRevision);
-			sqlite3_bind_text(_sGetNetworkRevision,1,nwids,16,SQLITE_STATIC);
-			bool networkExists = false;
-			if (sqlite3_step(_sGetNetworkRevision) == SQLITE_ROW) {
-				networkExists = true;
-				revision = sqlite3_column_int64(_sGetNetworkRevision,0);
-			}
-			*/
-
 			if (path.size() >= 3) {
-				auto network = networks.get<const json::object_t *>(nwids);
-				if (!network) return 404;
+				json network(_readJson(_networkJP(nwid,false)));
+				if (!network.size())
+					return 404;
 
 				if ((path.size() == 4)&&(path[2] == "member")&&(path[3].length() == 10)) {
-					json &members = (*network)["member"];
-					if (!members.is_object()) members = json::object();
-
 					uint64_t address = Utils::hexStrToU64(path[3].c_str());
-					char addrs[24];
-					Utils::snprintf(addrs,sizeof(addrs),"%.10llx",address);
-					json &member = members[addrs];
-					if (!member.is_object()) member = json::object();
 
 					/*
 					int64_t addToNetworkRevision = 0;
@@ -1256,6 +1236,9 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 
 					return _doCPGet(path,urlArgs,headers,body,responseBody,responseContentType);
 				} else if ((path.size() == 3)&&(path[2] == "test")) {
+
+					Mutex::Lock _l(_circuitTests_m);
+
 					ZT_CircuitTest *test = (ZT_CircuitTest *)malloc(sizeof(ZT_CircuitTest));
 					memset(test,0,sizeof(ZT_CircuitTest));
 
@@ -1263,6 +1246,7 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 					test->credentialNetworkId = nwid;
 					test->ptr = (void *)this;
 
+					// TODO TODO
 					/*
 					json_value *j = json_parse(body.c_str(),body.length());
 					if (j) {
@@ -1312,12 +1296,13 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 					responseBody = json;
 					responseContentType = "application/json";
 					return 200;
+
 				} // else 404
 
 			} else {
 				// POST to network ID
 
-				json::object b;
+				json b;
 				try {
 					b = json::parse(body);
 				} catch ( ... ) {
@@ -1334,7 +1319,7 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 						uint64_t tryNwid = nwidPrefix | (nwidPostfix & 0xffffffULL);
 						if ((tryNwid & 0xffffffULL) == 0ULL) tryNwid |= 1ULL;
 						Utils::snprintf(nwids,sizeof(nwids),"%.16llx",(unsigned long long)tryNwid);
-						if (!networks.get<const json::object_t *>(nwids)) {
+						if (!OSUtils::fileExists(_networkJP(tryNwid,false).c_str())) {
 							nwid = tryNwid;
 							break;
 						}
@@ -1343,24 +1328,23 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 						return 503;
 				}
 
-				json::object &network = networks[nwids];
-				if (!network.is_object()) network = json::object();
+				json network(_readJson(_networkJP(nwid,true)));
 
 				try {
-					if (b.count("name")) network["name"] = b.get<std::string>("name");
-					if (b.count("private")) network["private"] = b.get<bool>("private");
-					if (b.count("enableBroadcast")) network["enableBroadcast"] = b.get<bool>("enableBroadcast");
-					if (b.count("allowPassiveBridging")) network["allowPassiveBridging"] = b.get<bool>("allowPassiveBridging");
-					if (b.count("multicastLimit")) network["multicastLimit"] = b.get<uint64_t>("multicastLimit");
+					if (b.count("name")) network["name"] = b.value("name","");
+					if (b.count("private")) network["private"] = b.value("private",true);
+					if (b.count("enableBroadcast")) network["enableBroadcast"] = b.value("enableBroadcast",false);
+					if (b.count("allowPassiveBridging")) network["allowPassiveBridging"] = b.value("allowPassiveBridging",false);
+					if (b.count("multicastLimit")) network["multicastLimit"] = b.value("multicastLimit",32ULL);
 
 					if (b.count("v4AssignMode")) {
 						auto nv4m = network["v4AssignMode"];
-						if (!nv4m.is_object()) nv6m = json::object();
+						if (!nv4m.is_object()) nv4m = json::object();
 						if (b["v4AssignMode"].is_string()) { // backward compatibility
-							nv4m["zt"] = (b.get<std::string>("v4AssignMode") == "zt");
+							nv4m["zt"] = (b.value("v4AssignMode","") == "zt");
 						} else if (b["v4AssignMode"].is_object()) {
 							auto v4m = b["v4AssignMode"];
-							if (v4m.count("zt")) nv4m["zt"] = v4m.get<bool>("zt");
+							if (v4m.count("zt")) nv4m["zt"] = v4m.value("zt",false);
 						}
 						if (!nv4m.count("zt")) nv4m["zt"] = false;
 					}
@@ -1369,7 +1353,7 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 						auto nv6m = network["v6AssignMode"];
 						if (!nv6m.is_object()) nv6m = json::object();
 						if (b["v6AssignMode"].is_string()) { // backward compatibility
-							std::vector<std::string> v6m(Utils::split(b.get<std::string>("v6AssignMode").c_str(),",","",""));
+							std::vector<std::string> v6m(Utils::split(b.value("v6AssignMode","").c_str(),",","",""));
 							std::sort(v6m.begin(),v6m.end());
 							v6m.erase(std::unique(v6m.begin(),v6m.end()),v6m.end());
 							for(std::vector<std::string>::iterator i(v6m.begin());i!=v6m.end();++i) {
@@ -1382,9 +1366,9 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 							}
 						} else if (b["v6AssignMode"].is_object()) {
 							auto v6m = b["v6AssignMode"];
-							if (v6m.count("rfc4193")) nv6m["rfc4193"] = v6m.get<bool>("rfc4193");
-							if (v6m.count("zt")) nv6m["rfc4193"] = v6m.get<bool>("zt");
-							if (v6m.count("6plane")) nv6m["rfc4193"] = v6m.get<bool>("6plane");
+							if (v6m.count("rfc4193")) nv6m["rfc4193"] = v6m.value("rfc4193",false);
+							if (v6m.count("zt")) nv6m["rfc4193"] = v6m.value("zt",false);
+							if (v6m.count("6plane")) nv6m["rfc4193"] = v6m.value("6plane",false);
 						}
 						if (!nv6m.count("rfc4193")) nv6m["rfc4193"] = false;
 						if (!nv6m.count("zt")) nv6m["zt"] = false;
@@ -1397,14 +1381,14 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 							for(unsigned long i=0;i<rts.size();++i) {
 								auto rt = rts[i];
 								if ((rt.is_object())&&(rt.count("target"))&&(rt.count("via"))) {
-									InetAddress t(rt.get<std::string>("target"));
-									InetAddress v(rt.get<std::string>("via"));
+									InetAddress t(rt.value("target",""));
+									InetAddress v(rt.value("via",""));
 									if ( ((t.ss_family == AF_INET)||(t.ss_family == AF_INET6)) && (t.ss_family == v.ss_family) && (t.netmaskBitsValid()) ) {
 										auto nrts = network["routes"];
 										if (!nrts.is_array()) nrts = json::array();
-										json::object tmp;
-										tmp["target"] = target.toString();
-										tmp["via"] = target.toIpString();
+										json tmp;
+										tmp["target"] = t.toString();
+										tmp["via"] = v.toIpString();
 										nrts.push_back(tmp);
 									}
 								}
@@ -1418,12 +1402,12 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 							for(unsigned long i=0;i<ipp.size();++i) {
 								auto ip = ipp[i];
 								if ((ip.is_object())&&(ip.count("ipRangeStart"))&&(ip.count("ipRangeEnd"))) {
-									InetAddress f(ip.get<std::string>("ipRangeStart"));
-									InetAddress t(ip.get<std::string>("ipRangeEnd"));
+									InetAddress f(ip.value("ipRangeStart",""));
+									InetAddress t(ip.value("ipRangeEnd",""));
 									if ( ((f.ss_family == AF_INET)||(f.ss_family == AF_INET6)) && (f.ss_family == t.ss_family) ) {
 										auto nipp = network["ipAssignmentPools"];
 										if (!nipp.is_array()) nipp = json::array();
-										json::object tmp;
+										json tmp;
 										tmp["ipRangeStart"] = f.toIpString();
 										tmp["ipRangeEnd"] = t.toIpString();
 										nipp.push_back(tmp);
@@ -1461,328 +1445,14 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpPOST(
 				}
 
 				network["lastModified"] = OSUtils::now();
-				network["revision"] = network.get<uint64_t>("revision") + 1ULL;
-
-				return _doCPGet(path_copy,urlArgs,headers,body,responseBody,responseContentType);
-
-				/*
-				json_value *j = json_parse(body.c_str(),body.length());
-				if (j) {
-					if (j->type == json_object) {
-						for(unsigned int k=0;k<j->u.object.length;++k) {
-							sqlite3_stmt *stmt = (sqlite3_stmt *)0;
-
-							if (!strcmp(j->u.object.values[k].name,"name")) {
-								if ((j->u.object.values[k].value->type == json_string)&&(j->u.object.values[k].value->u.string.ptr[0])) {
-									if (sqlite3_prepare_v2(_db,"UPDATE Network SET \"name\" = ? WHERE id = ?",-1,&stmt,(const char **)0) == SQLITE_OK)
-										sqlite3_bind_text(stmt,1,j->u.object.values[k].value->u.string.ptr,-1,SQLITE_STATIC);
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"private")) {
-								if (j->u.object.values[k].value->type == json_boolean) {
-									if (sqlite3_prepare_v2(_db,"UPDATE Network SET \"private\" = ? WHERE id = ?",-1,&stmt,(const char **)0) == SQLITE_OK)
-										sqlite3_bind_int(stmt,1,(j->u.object.values[k].value->u.boolean == 0) ? 0 : 1);
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"enableBroadcast")) {
-								if (j->u.object.values[k].value->type == json_boolean) {
-									if (sqlite3_prepare_v2(_db,"UPDATE Network SET enableBroadcast = ? WHERE id = ?",-1,&stmt,(const char **)0) == SQLITE_OK)
-										sqlite3_bind_int(stmt,1,(j->u.object.values[k].value->u.boolean == 0) ? 0 : 1);
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"allowPassiveBridging")) {
-								if (j->u.object.values[k].value->type == json_boolean) {
-									if (sqlite3_prepare_v2(_db,"UPDATE Network SET allowPassiveBridging = ? WHERE id = ?",-1,&stmt,(const char **)0) == SQLITE_OK)
-										sqlite3_bind_int(stmt,1,(j->u.object.values[k].value->u.boolean == 0) ? 0 : 1);
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"v4AssignMode")) {
-								if ((j->u.object.values[k].value->type == json_string)&&(!strcmp(j->u.object.values[k].value->u.string.ptr,"zt"))) {
-									if (sqlite3_prepare_v2(_db,"UPDATE Network SET \"flags\" = (\"flags\" | ?) WHERE id = ?",-1,&stmt,(const char **)0) == SQLITE_OK)
-										sqlite3_bind_int(stmt,1,(int)ZT_DB_NETWORK_FLAG_ZT_MANAGED_V4_AUTO_ASSIGN);
-								} else {
-									if (sqlite3_prepare_v2(_db,"UPDATE Network SET \"flags\" = (\"flags\" & ?) WHERE id = ?",-1,&stmt,(const char **)0) == SQLITE_OK)
-										sqlite3_bind_int(stmt,1,(int)(ZT_DB_NETWORK_FLAG_ZT_MANAGED_V4_AUTO_ASSIGN ^ 0xfffffff));
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"v6AssignMode")) {
-								int fl = 0;
-								if (j->u.object.values[k].value->type == json_string) {
-									char *saveptr = (char *)0;
-									for(char *f=Utils::stok(j->u.object.values[k].value->u.string.ptr,",",&saveptr);(f);f=Utils::stok((char *)0,",",&saveptr)) {
-										if (!strcmp(f,"rfc4193"))
-											fl |= ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_RFC4193;
-										else if (!strcmp(f,"6plane"))
-											fl |= ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_6PLANE;
-										else if (!strcmp(f,"zt"))
-											fl |= ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_AUTO_ASSIGN;
-									}
-								}
-								if (sqlite3_prepare_v2(_db,"UPDATE Network SET \"flags\" = ((\"flags\" & " ZT_DB_NETWORK_FLAG_ZT_MANAGED_V6_MASK_S ") | ?) WHERE id = ?",-1,&stmt,(const char **)0) == SQLITE_OK)
-									sqlite3_bind_int(stmt,1,fl);
-							} else if (!strcmp(j->u.object.values[k].name,"multicastLimit")) {
-								if (j->u.object.values[k].value->type == json_integer) {
-									if (sqlite3_prepare_v2(_db,"UPDATE Network SET multicastLimit = ? WHERE id = ?",-1,&stmt,(const char **)0) == SQLITE_OK)
-										sqlite3_bind_int(stmt,1,(int)j->u.object.values[k].value->u.integer);
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"relays")) {
-								if (j->u.object.values[k].value->type == json_array) {
-									std::map<Address,InetAddress> nodeIdToPhyAddress;
-									for(unsigned int kk=0;kk<j->u.object.values[k].value->u.array.length;++kk) {
-										json_value *relay = j->u.object.values[k].value->u.array.values[kk];
-										const char *address = (const char *)0;
-										const char *phyAddress = (const char *)0;
-										if ((relay)&&(relay->type == json_object)) {
-											for(unsigned int rk=0;rk<relay->u.object.length;++rk) {
-												if ((!strcmp(relay->u.object.values[rk].name,"address"))&&(relay->u.object.values[rk].value->type == json_string))
-													address = relay->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(relay->u.object.values[rk].name,"phyAddress"))&&(relay->u.object.values[rk].value->type == json_string))
-													phyAddress = relay->u.object.values[rk].value->u.string.ptr;
-											}
-										}
-										if ((address)&&(phyAddress))
-											nodeIdToPhyAddress[Address(address)] = InetAddress(phyAddress);
-									}
-
-									sqlite3_reset(_sDeleteRelaysForNetwork);
-									sqlite3_bind_text(_sDeleteRelaysForNetwork,1,nwids,16,SQLITE_STATIC);
-									sqlite3_step(_sDeleteRelaysForNetwork);
-
-									for(std::map<Address,InetAddress>::iterator rl(nodeIdToPhyAddress.begin());rl!=nodeIdToPhyAddress.end();++rl) {
-										sqlite3_reset(_sCreateRelay);
-										sqlite3_bind_text(_sCreateRelay,1,nwids,16,SQLITE_STATIC);
-										std::string a(rl->first.toString()),b(rl->second.toString()); // don't destroy strings until sqlite3_step()
-										sqlite3_bind_text(_sCreateRelay,2,a.c_str(),-1,SQLITE_STATIC);
-										sqlite3_bind_text(_sCreateRelay,3,b.c_str(),-1,SQLITE_STATIC);
-										sqlite3_step(_sCreateRelay);
-									}
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"routes")) {
-								sqlite3_reset(_sDeleteRoutes);
-								sqlite3_bind_text(_sDeleteRoutes,1,nwids,16,SQLITE_STATIC);
-								sqlite3_step(_sDeleteRoutes);
-								if (j->u.object.values[k].value->type == json_array) {
-									for(unsigned int kk=0;kk<j->u.object.values[k].value->u.array.length;++kk) {
-										json_value *r = j->u.object.values[k].value->u.array.values[kk];
-										if ((r)&&(r->type == json_object)) {
-											InetAddress r_target,r_via;
-											int r_flags = 0;
-											int r_metric = 0;
-											for(unsigned int rk=0;rk<r->u.object.length;++rk) {
-												if ((!strcmp(r->u.object.values[rk].name,"target"))&&(r->u.object.values[rk].value->type == json_string))
-													r_target = InetAddress(std::string(r->u.object.values[rk].value->u.string.ptr));
-												else if ((!strcmp(r->u.object.values[rk].name,"via"))&&(r->u.object.values[rk].value->type == json_string))
-													r_via = InetAddress(std::string(r->u.object.values[rk].value->u.string.ptr),0);
-												else if ((!strcmp(r->u.object.values[rk].name,"flags"))&&(r->u.object.values[rk].value->type == json_integer))
-													r_flags = (int)(r->u.object.values[rk].value->u.integer & 0xffff);
-												else if ((!strcmp(r->u.object.values[rk].name,"metric"))&&(r->u.object.values[rk].value->type == json_integer))
-													r_metric = (int)(r->u.object.values[rk].value->u.integer & 0xffff);
-											}
-											if ((r_target)&&((!r_via)||(r_via.ss_family == r_target.ss_family))) {
-												int r_ipVersion = 0;
-												char r_targetBlob[16];
-												char r_viaBlob[16];
-												_ipToBlob(r_target,r_targetBlob,r_ipVersion);
-												if (r_ipVersion) {
-													int r_targetNetmaskBits = r_target.netmaskBits();
-													if ((r_ipVersion == 4)&&(r_targetNetmaskBits > 32)) r_targetNetmaskBits = 32;
-													else if ((r_ipVersion == 6)&&(r_targetNetmaskBits > 128)) r_targetNetmaskBits = 128;
-													sqlite3_reset(_sCreateRoute);
-													sqlite3_bind_text(_sCreateRoute,1,nwids,16,SQLITE_STATIC);
-													sqlite3_bind_blob(_sCreateRoute,2,(const void *)r_targetBlob,16,SQLITE_STATIC);
-													if (r_via) {
-														_ipToBlob(r_via,r_viaBlob,r_ipVersion);
-														sqlite3_bind_blob(_sCreateRoute,3,(const void *)r_viaBlob,16,SQLITE_STATIC);
-													} else {
-														sqlite3_bind_null(_sCreateRoute,3);
-													}
-													sqlite3_bind_int(_sCreateRoute,4,r_targetNetmaskBits);
-													sqlite3_bind_int(_sCreateRoute,5,r_ipVersion);
-													sqlite3_bind_int(_sCreateRoute,6,r_flags);
-													sqlite3_bind_int(_sCreateRoute,7,r_metric);
-													sqlite3_step(_sCreateRoute);
-												}
-											}
-										}
-									}
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"ipAssignmentPools")) {
-								if (j->u.object.values[k].value->type == json_array) {
-									std::vector< std::pair<InetAddress,InetAddress> > pools;
-									for(unsigned int kk=0;kk<j->u.object.values[k].value->u.array.length;++kk) {
-										json_value *pool = j->u.object.values[k].value->u.array.values[kk];
-										const char *iprs = (const char *)0;
-										const char *ipre = (const char *)0;
-										if ((pool)&&(pool->type == json_object)) {
-											for(unsigned int rk=0;rk<pool->u.object.length;++rk) {
-												if ((!strcmp(pool->u.object.values[rk].name,"ipRangeStart"))&&(pool->u.object.values[rk].value->type == json_string))
-													iprs = pool->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(pool->u.object.values[rk].name,"ipRangeEnd"))&&(pool->u.object.values[rk].value->type == json_string))
-													ipre = pool->u.object.values[rk].value->u.string.ptr;
-											}
-										}
-										if ((iprs)&&(ipre)) {
-											InetAddress iprs2(iprs);
-											InetAddress ipre2(ipre);
-											if (iprs2.ss_family == ipre2.ss_family) {
-												iprs2.setPort(0);
-												ipre2.setPort(0);
-												pools.push_back(std::pair<InetAddress,InetAddress>(iprs2,ipre2));
-											}
-										}
-									}
-									std::sort(pools.begin(),pools.end());
-									pools.erase(std::unique(pools.begin(),pools.end()),pools.end());
-
-									sqlite3_reset(_sDeleteIpAssignmentPoolsForNetwork);
-									sqlite3_bind_text(_sDeleteIpAssignmentPoolsForNetwork,1,nwids,16,SQLITE_STATIC);
-									sqlite3_step(_sDeleteIpAssignmentPoolsForNetwork);
-
-									for(std::vector< std::pair<InetAddress,InetAddress> >::const_iterator p(pools.begin());p!=pools.end();++p) {
-										char ipBlob1[16],ipBlob2[16];
-										sqlite3_reset(_sCreateIpAssignmentPool);
-										sqlite3_bind_text(_sCreateIpAssignmentPool,1,nwids,16,SQLITE_STATIC);
-										if (p->first.ss_family == AF_INET) {
-											memset(ipBlob1,0,12);
-											memcpy(ipBlob1 + 12,p->first.rawIpData(),4);
-											memset(ipBlob2,0,12);
-											memcpy(ipBlob2 + 12,p->second.rawIpData(),4);
-											sqlite3_bind_blob(_sCreateIpAssignmentPool,2,(const void *)ipBlob1,16,SQLITE_STATIC);
-											sqlite3_bind_blob(_sCreateIpAssignmentPool,3,(const void *)ipBlob2,16,SQLITE_STATIC);
-											sqlite3_bind_int(_sCreateIpAssignmentPool,4,4);
-										} else if (p->first.ss_family == AF_INET6) {
-											sqlite3_bind_blob(_sCreateIpAssignmentPool,2,p->first.rawIpData(),16,SQLITE_STATIC);
-											sqlite3_bind_blob(_sCreateIpAssignmentPool,3,p->second.rawIpData(),16,SQLITE_STATIC);
-											sqlite3_bind_int(_sCreateIpAssignmentPool,4,6);
-										} else continue;
-										sqlite3_step(_sCreateIpAssignmentPool);
-									}
-								}
-							} else if (!strcmp(j->u.object.values[k].name,"rules")) {
-								if (j->u.object.values[k].value->type == json_array) {
-									sqlite3_reset(_sDeleteRulesForNetwork);
-									sqlite3_bind_text(_sDeleteRulesForNetwork,1,nwids,16,SQLITE_STATIC);
-									sqlite3_step(_sDeleteRulesForNetwork);
-
-									for(unsigned int kk=0;kk<j->u.object.values[k].value->u.array.length;++kk) {
-										json_value *rj = j->u.object.values[k].value->u.array.values[kk];
-										if ((rj)&&(rj->type == json_object)) {
-											struct { // NULL pointers indicate missing or NULL -- wildcards
-												const json_int_t *ruleNo;
-												const char *nodeId;
-												const char *sourcePort;
-												const char *destPort;
-												const json_int_t *vlanId;
-												const json_int_t *vlanPcp;
-												const json_int_t *etherType;
-												const char *macSource;
-												const char *macDest;
-												const char *ipSource;
-												const char *ipDest;
-												const json_int_t *ipTos;
-												const json_int_t *ipProtocol;
-												const json_int_t *ipSourcePort;
-												const json_int_t *ipDestPort;
-												const json_int_t *flags;
-												const json_int_t *invFlags;
-												const char *action;
-											} rule;
-											memset(&rule,0,sizeof(rule));
-
-											for(unsigned int rk=0;rk<rj->u.object.length;++rk) {
-												if ((!strcmp(rj->u.object.values[rk].name,"ruleNo"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.ruleNo = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"nodeId"))&&(rj->u.object.values[rk].value->type == json_string))
-													rule.nodeId = rj->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(rj->u.object.values[rk].name,"sourcePort"))&&(rj->u.object.values[rk].value->type == json_string))
-													rule.sourcePort = rj->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(rj->u.object.values[rk].name,"destPort"))&&(rj->u.object.values[rk].value->type == json_string))
-													rule.destPort = rj->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(rj->u.object.values[rk].name,"vlanId"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.vlanId = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"vlanPcp"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.vlanPcp = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"etherType"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.etherType = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"macSource"))&&(rj->u.object.values[rk].value->type == json_string))
-													rule.macSource = rj->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(rj->u.object.values[rk].name,"macDest"))&&(rj->u.object.values[rk].value->type == json_string))
-													rule.macDest = rj->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(rj->u.object.values[rk].name,"ipSource"))&&(rj->u.object.values[rk].value->type == json_string))
-													rule.ipSource = rj->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(rj->u.object.values[rk].name,"ipDest"))&&(rj->u.object.values[rk].value->type == json_string))
-													rule.ipDest = rj->u.object.values[rk].value->u.string.ptr;
-												else if ((!strcmp(rj->u.object.values[rk].name,"ipTos"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.ipTos = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"ipProtocol"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.ipProtocol = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"ipSourcePort"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.ipSourcePort = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"ipDestPort"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.ipDestPort = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"flags"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.flags = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"invFlags"))&&(rj->u.object.values[rk].value->type == json_integer))
-													rule.invFlags = &(rj->u.object.values[rk].value->u.integer);
-												else if ((!strcmp(rj->u.object.values[rk].name,"action"))&&(rj->u.object.values[rk].value->type == json_string))
-													rule.action = rj->u.object.values[rk].value->u.string.ptr;
-											}
-
-											if ((rule.ruleNo)&&(rule.action)&&(rule.action[0])) {
-												char mactmp1[16],mactmp2[16];
-												sqlite3_reset(_sCreateRule);
-												sqlite3_bind_text(_sCreateRule,1,nwids,16,SQLITE_STATIC);
-												sqlite3_bind_int64(_sCreateRule,2,*rule.ruleNo);
-
-												// Optional values: null by default
-												for(int i=3;i<=18;++i)
-													sqlite3_bind_null(_sCreateRule,i);
-												if ((rule.nodeId)&&(strlen(rule.nodeId) == 10)) sqlite3_bind_text(_sCreateRule,3,rule.nodeId,10,SQLITE_STATIC);
-												if ((rule.sourcePort)&&(strlen(rule.sourcePort) == 10)) sqlite3_bind_text(_sCreateRule,4,rule.sourcePort,10,SQLITE_STATIC);
-												if ((rule.destPort)&&(strlen(rule.destPort) == 10)) sqlite3_bind_text(_sCreateRule,5,rule.destPort,10,SQLITE_STATIC);
-												if (rule.vlanId) sqlite3_bind_int(_sCreateRule,6,(int)*rule.vlanId);
-												if (rule.vlanPcp) sqlite3_bind_int(_sCreateRule,7,(int)*rule.vlanPcp);
-												if (rule.etherType) sqlite3_bind_int(_sCreateRule,8,(int)*rule.etherType & (int)0xffff);
-												if (rule.macSource) {
-													MAC m(rule.macSource);
-													Utils::snprintf(mactmp1,sizeof(mactmp1),"%.12llx",(unsigned long long)m.toInt());
-													sqlite3_bind_text(_sCreateRule,9,mactmp1,-1,SQLITE_STATIC);
-												}
-												if (rule.macDest) {
-													MAC m(rule.macDest);
-													Utils::snprintf(mactmp2,sizeof(mactmp2),"%.12llx",(unsigned long long)m.toInt());
-													sqlite3_bind_text(_sCreateRule,10,mactmp2,-1,SQLITE_STATIC);
-												}
-												if (rule.ipSource) sqlite3_bind_text(_sCreateRule,11,rule.ipSource,-1,SQLITE_STATIC);
-												if (rule.ipDest) sqlite3_bind_text(_sCreateRule,12,rule.ipDest,-1,SQLITE_STATIC);
-												if (rule.ipTos) sqlite3_bind_int(_sCreateRule,13,(int)*rule.ipTos);
-												if (rule.ipProtocol) sqlite3_bind_int(_sCreateRule,14,(int)*rule.ipProtocol);
-												if (rule.ipSourcePort) sqlite3_bind_int(_sCreateRule,15,(int)*rule.ipSourcePort & (int)0xffff);
-												if (rule.ipDestPort) sqlite3_bind_int(_sCreateRule,16,(int)*rule.ipDestPort & (int)0xffff);
-												if (rule.flags) sqlite3_bind_int64(_sCreateRule,17,(int64_t)*rule.flags);
-												if (rule.invFlags) sqlite3_bind_int64(_sCreateRule,18,(int64_t)*rule.invFlags);
-
-												sqlite3_bind_text(_sCreateRule,19,rule.action,-1,SQLITE_STATIC);
-												sqlite3_step(_sCreateRule);
-											}
-										}
-									}
-								}
-							}
+				network["revision"] = network.value("revision",0ULL) + 1ULL;
 
-							if (stmt) {
-								sqlite3_bind_text(stmt,2,nwids,16,SQLITE_STATIC);
-								sqlite3_step(stmt);
-								sqlite3_finalize(stmt);
-							}
-						}
-					}
-					json_value_free(j);
-				}
-
-				sqlite3_reset(_sSetNetworkRevision);
-				sqlite3_bind_int64(_sSetNetworkRevision,1,revision += 1);
-				sqlite3_bind_text(_sSetNetworkRevision,2,nwids,16,SQLITE_STATIC);
-				sqlite3_step(_sSetNetworkRevision);
+				_writeJson(_networkJP(nwid,true),network);
 
-				return _doCPGet(path_copy,urlArgs,headers,body,responseBody,responseContentType);
-			}
-			*/
+				responseBody = network.dump(2);
+				responseContentType = "application/json";
+				return 200;
+			} // else 404
 
 		} // else 404
 
@@ -1801,38 +1471,32 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpDELETE(
 {
 	if (path.empty())
 		return 404;
-	Mutex::Lock _l(_lock);
 
 	if (path[0] == "network") {
-		auto networks = _db.get<const json::object_t *>("network");
-		if (!networks) return 404;
-
 		if ((path.size() >= 2)&&(path[1].length() == 16)) {
 			const uint64_t nwid = Utils::hexStrToU64(path[1].c_str());
-			char nwids[24];
-			Utils::snprintf(nwids,sizeof(nwids),"%.16llx",(unsigned long long)nwid);
-			auto network = _db.get<const json::object_t *>(nwids);
-			if (!network) return 404;
+
+			json network(_readJson(_networkJP(nwid,false)));
+			if (!network.size())
+				return 404;
 
 			if (path.size() >= 3) {
 				if ((path.size() == 4)&&(path[2] == "member")&&(path[3].length() == 10)) {
-					auto members = network->get<const json::object_t *>("member");
-					if (!members) return 404;
-
 					const uint64_t address = Utils::hexStrToU64(path[3].c_str());
-					char addrs[24];
-					Utils::snprintf(addrs,sizeof(addrs),"%.10llx",address);
-					auto member = members->get<const json::object_t *>(addrs);
-					if (!member) return 404;
 
-					members->erase(addrs);
-					responseBody = member->dump(2);
+					json member(_readJson(_memberJP(nwid,Address(address),false)));
+					if (!member.size())
+						return 404;
+
+					OSUtils::rmDashRf(_memberBP(nwid,Address(address),false).c_str());
+
+					responseBody = member.dump(2);
 					responseContentType = "application/json";
 					return 200;
 				}
 			} else {
-				networks->erase(nwids);
-				responseBody = network->dump(2);
+				OSUtils::rmDashRf(_networkBP(nwid,false).c_str());
+				responseBody = network.dump(2);
 				responseContentType = "application/json";
 				return 200;
 			}
@@ -1843,27 +1507,6 @@ unsigned int SqliteNetworkController::handleControlPlaneHttpDELETE(
 	return 404;
 }
 
-void SqliteNetworkController::threadMain()
-	throw()
-{
-	uint64_t lastCommit = OSUtils::now();
-	while(_dbCommitThreadRun) {
-		Thread::sleep(200);
-		if ((OSUtils::now() - lastCommit) > 2000) {
-			lastCommit = OSUtils::now();
-			try {
-				std::vector<std::string> errors;
-				Mutex::Lock _l(_lock);
-				if (!_db.commit(&errors)) {
-					// TODO: handle anything really bad
-				}
-			} catch ( ... ) {
-				// TODO: handle anything really bad
-			}
-		}
-	}
-}
-
 unsigned int SqliteNetworkController::_doCPGet(
 	const std::vector<std::string> &path,
 	const std::map<std::string,std::string> &urlArgs,
@@ -1874,137 +1517,79 @@ unsigned int SqliteNetworkController::_doCPGet(
 {
 	// Assumes _lock is locked
 	if ((path.size() > 0)&&(path[0] == "network")) {
-		auto networks = _db.get<const json::object_t *>("network");
-		if (!networks) return 404;
 
 		if ((path.size() >= 2)&&(path[1].length() == 16)) {
 			const uint64_t nwid = Utils::hexStrToU64(path[1].c_str());
 			char nwids[24];
 			Utils::snprintf(nwids,sizeof(nwids),"%.16llx",(unsigned long long)nwid);
-			auto network = _db.get<const json::object_t *>(nwids);
-			if (!network) return 404;
+
+			json network(_readJson(_networkJP(nwid,false)));
+			if (!network.size())
+				return 404;
 
 			if (path.size() >= 3) {
 
 				if (path[2] == "member") {
-					auto members = network->get<const json::object_t *>("member");
-					if (!members) return 404;
 
 					if (path.size() >= 4) {
 						const uint64_t address = Utils::hexStrToU64(path[3].c_str());
+
+						json member(_readJson(_memberJP(nwid,Address(address),false)));
+						if (!member.size())
+							return 404;
+
 						char addrs[24];
 						Utils::snprintf(addrs,sizeof(addrs),"%.10llx",address);
-						auto member = members->get<const json::object_t *>(addrs);
-						if (!member) return 404;
 
-						nlohmann::json o(member);
+						json o(member);
 						o["nwid"] = nwids;
 						o["address"] = addrs;
-						o["controllerInstanceId"] = _instanceId;
 						o["clock"] = OSUtils::now();
 						responseBody = o.dump(2);
 						responseContentType = "application/json";
-						return 200;
 
-						/*
-						sqlite3_reset(_sGetMember2);
-						sqlite3_bind_text(_sGetMember2,1,nwids,16,SQLITE_STATIC);
-						sqlite3_bind_text(_sGetMember2,2,addrs,10,SQLITE_STATIC);
-						if (sqlite3_step(_sGetMember2) == SQLITE_ROW) {
-							const char *memberIdStr = (const char *)sqlite3_column_text(_sGetMember2,3);
-
-							Utils::snprintf(json,sizeof(json),
-								"{\n"
-								"\t\"nwid\": \"%s\",\n"
-								"\t\"address\": \"%s\",\n"
-								"\t\"controllerInstanceId\": \"%s\",\n"
-								"\t\"authorized\": %s,\n"
-								"\t\"activeBridge\": %s,\n"
-								"\t\"memberRevision\": %llu,\n"
-								"\t\"clock\": %llu,\n"
-								"\t\"identity\": \"%s\",\n"
-								"\t\"ipAssignments\": [",
-								nwids,
-								addrs,
-								_instanceId.c_str(),
-								(sqlite3_column_int(_sGetMember2,0) > 0) ? "true" : "false",
-								(sqlite3_column_int(_sGetMember2,1) > 0) ? "true" : "false",
-								(unsigned long long)sqlite3_column_int64(_sGetMember2,2),
-								(unsigned long long)OSUtils::now(),
-								_jsonEscape(memberIdStr).c_str());
-							responseBody = json;
-
-							sqlite3_reset(_sGetIpAssignmentsForNode);
-							sqlite3_bind_text(_sGetIpAssignmentsForNode,1,nwids,16,SQLITE_STATIC);
-							sqlite3_bind_text(_sGetIpAssignmentsForNode,2,addrs,10,SQLITE_STATIC);
-							bool firstIp = true;
-							while (sqlite3_step(_sGetIpAssignmentsForNode) == SQLITE_ROW) {
-								int ipversion = sqlite3_column_int(_sGetIpAssignmentsForNode,2);
-								char ipBlob[16];
-								memcpy(ipBlob,(const void *)sqlite3_column_blob(_sGetIpAssignmentsForNode,0),16);
-								InetAddress ip(
-									(const void *)(ipversion == 6 ? ipBlob : &ipBlob[12]),
-									(ipversion == 6 ? 16 : 4),
-									(unsigned int)sqlite3_column_int(_sGetIpAssignmentsForNode,1)
-								);
-								responseBody.append(firstIp ? "\"" : ",\"");
-								responseBody.append(_jsonEscape(ip.toIpString()));
-								responseBody.push_back('"');
-								firstIp = false;
-							}
-
-							responseBody.append("],\n\t\"recentLog\": [");
+						return 200;
+					} else {
 
-							const void *histb = sqlite3_column_blob(_sGetMember2,6);
-							if (histb) {
-								MemberRecentHistory rh;
-								rh.fromBlob((const char *)histb,sqlite3_column_bytes(_sGetMember2,6));
-								for(MemberRecentHistory::const_iterator i(rh.begin());i!=rh.end();++i) {
-									if (i != rh.begin())
-										responseBody.push_back(',');
+						responseBody = "{";
+						std::vector<std::string> members(OSUtils::listSubdirectories((_networkBP(nwid,false) + ZT_PATH_SEPARATOR_S + "member").c_str()));
+						for(std::vector<std::string>::iterator i(members.begin());i!=members.end();++i) {
+							if (i->length() == ZT_ADDRESS_LENGTH_HEX) {
+								json member(_readJson(_memberJP(nwid,Address(Utils::hexStrToU64(i->c_str())),false)));
+								if (member.size()) {
+									responseBody.append((responseBody.length() == 1) ? "\"" : ",\"");
 									responseBody.append(*i);
+									responseBody.append("\":");
+									const std::string rc = member.value("memberRevision","0");
+									responseBody.append(rc);
 								}
 							}
-
-							responseBody.append("]\n}\n");
-
-							responseContentType = "application/json";
-							return 200;
-						} // else 404
-						*/
-
-					} else {
-
-						responseBody.push_back('{');
-						for(auto i(members->begin());i!=members->end();++i) {
-							responseBody.append((i == members->begin()) ? "\"" : ",\"");
-							responseBody.append(i->key());
-							responseBody.append("\":\"");
-							const std::string rc = i->value().value("memberRevision","0");
-							responseBody.append(rc);
-							responseBody.append('"');
 						}
 						responseBody.push_back('}');
 						responseContentType = "application/json";
-						return 200;
 
+						return 200;
 					}
 
 				} else if ((path[2] == "active")&&(path.size() == 3)) {
 
-					responseBody.push_back('{');
-					bool firstMember = true;
+					responseBody = "{";
+					std::vector<std::string> members(OSUtils::listSubdirectories((_networkBP(nwid,false) + ZT_PATH_SEPARATOR_S + "member").c_str()));
 					const uint64_t threshold = OSUtils::now() - ZT_NETCONF_NODE_ACTIVE_THRESHOLD;
-					for(auto i(members->begin());i!=members->end();++i) {
-						auto recentLog = i->value()->get<const json::array_t *>("recentLog");
-						if ((recentLog)&&(recentLog.size() > 0)) {
-							auto mostRecentLog = recentLog[0];
-							if ((mostRecentLog.is_object())&&((uint64_t)mostRecentLog.value("ts",0ULL) >= threshold)) {
-								responseBody.append((firstMember) ? "\"" : ",\"");
-								firstMember = false;
-								responseBody.append(i->key());
-								responseBody.append("\":");
-								responseBody.append(mostRecentLog.dump());
+					for(std::vector<std::string>::iterator i(members.begin());i!=members.end();++i) {
+						if (i->length() == ZT_ADDRESS_LENGTH_HEX) {
+							json member(_readJson(_memberJP(nwid,Address(Utils::hexStrToU64(i->c_str())),false)));
+							if (member.size()) {
+								auto recentLog = member["recentLog"];
+								if ((recentLog.is_array())&&(recentLog.size() > 0)) {
+									auto mostRecentLog = recentLog[0];
+									if ((mostRecentLog.is_object())&&((uint64_t)mostRecentLog.value("ts",0ULL) >= threshold)) {
+										responseBody.append((responseBody.length() == 1) ? "\"" : ",\"");
+										responseBody.append(*i);
+										responseBody.append("\":");
+										responseBody.append(mostRecentLog.dump());
+									}
+								}
 							}
 						}
 					}
@@ -2014,6 +1599,7 @@ unsigned int SqliteNetworkController::_doCPGet(
 
 				} else if ((path[2] == "test")&&(path.size() >= 4)) {
 
+					Mutex::Lock _l(_circuitTests_m);
 					std::map< uint64_t,_CircuitTestEntry >::iterator cte(_circuitTests.find(Utils::hexStrToU64(path[3].c_str())));
 					if ((cte != _circuitTests.end())&&(cte->second.test)) {
 
@@ -2032,7 +1618,6 @@ unsigned int SqliteNetworkController::_doCPGet(
 
 				nlohmann::json o(network);
 				o["nwid"] = nwids;
-				o["controllerInstanceId"] = _instanceId;
 				o["clock"] = OSUtils::now();
 				responseBody = o.dump(2);
 				responseContentType = "application/json";
@@ -2042,10 +1627,13 @@ unsigned int SqliteNetworkController::_doCPGet(
 		} else if (path.size() == 1) {
 
 			responseBody = "[";
-			for(auto i(networks->begin());i!=networks.end();++i) {
-				responseBody.append((i == networks->begin()) ? "\"" : ",\"");
-				responseBody.append(i->key());
-				responseBody.append("\"");
+			std::vector<std::string> networks(OSUtils::listSubdirectories((_path + ZT_PATH_SEPARATOR_S + "network").c_str()));
+			for(auto i(networks.begin());i!=networks.end();++i) {
+				if (i->length() == 16) {
+					responseBody.append((responseBody.length() == 1) ? "\"" : ",\"");
+					responseBody.append(*i);
+					responseBody.append("\"");
+				}
 			}
 			responseBody.push_back(']');
 			responseContentType = "application/json";
@@ -2053,16 +1641,11 @@ unsigned int SqliteNetworkController::_doCPGet(
 
 		} // else 404
 
-	} else if ((path.size() > 0)&&(path[0] == "_dump")) {
-
-		responseBody = _db.dump(2);
-		responseContentType = "application/json";
-		return 200;
-
 	} else {
 
-		Utils::snprintf(json,sizeof(json),"{\n\t\"controller\": true,\n\t\"apiVersion\": %d,\n\t\"clock\": %llu,\n\t\"instanceId\": \"%s\"\n}\n",ZT_NETCONF_CONTROLLER_API_VERSION,(unsigned long long)OSUtils::now(),_instanceId.c_str());
-		responseBody = json;
+		char tmp[4096];
+		Utils::snprintf(tmp,sizeof(tmp),"{\n\t\"controller\": true,\n\t\"apiVersion\": %d,\n\t\"clock\": %llu\n}\n",ZT_NETCONF_CONTROLLER_API_VERSION,(unsigned long long)OSUtils::now());
+		responseBody = tmp;
 		responseContentType = "application/json";
 		return 200;
 
@@ -2081,7 +1664,7 @@ void SqliteNetworkController::_circuitTestCallback(ZT_Node *node,ZT_CircuitTest
 	if (!report)
 		return;
 
-	Mutex::Lock _l(self->_lock);
+	Mutex::Lock _l(self->_circuitTests_m);
 	std::map< uint64_t,_CircuitTestEntry >::iterator cte(self->_circuitTests.find(test->testId));
 
 	if (cte == self->_circuitTests.end()) { // sanity check: a circuit test we didn't launch?
@@ -2092,25 +1675,25 @@ void SqliteNetworkController::_circuitTestCallback(ZT_Node *node,ZT_CircuitTest
 
 	Utils::snprintf(tmp,sizeof(tmp),
 		"%s{\n"
-		"\t\"timestamp\": %llu,"ZT_EOL_S
-		"\t\"testId\": \"%.16llx\","ZT_EOL_S
-		"\t\"upstream\": \"%.10llx\","ZT_EOL_S
-		"\t\"current\": \"%.10llx\","ZT_EOL_S
-		"\t\"receivedTimestamp\": %llu,"ZT_EOL_S
-		"\t\"remoteTimestamp\": %llu,"ZT_EOL_S
-		"\t\"sourcePacketId\": \"%.16llx\","ZT_EOL_S
-		"\t\"flags\": %llu,"ZT_EOL_S
-		"\t\"sourcePacketHopCount\": %u,"ZT_EOL_S
-		"\t\"errorCode\": %u,"ZT_EOL_S
-		"\t\"vendor\": %d,"ZT_EOL_S
-		"\t\"protocolVersion\": %u,"ZT_EOL_S
-		"\t\"majorVersion\": %u,"ZT_EOL_S
-		"\t\"minorVersion\": %u,"ZT_EOL_S
-		"\t\"revision\": %u,"ZT_EOL_S
-		"\t\"platform\": %d,"ZT_EOL_S
-		"\t\"architecture\": %d,"ZT_EOL_S
-		"\t\"receivedOnLocalAddress\": \"%s\","ZT_EOL_S
-		"\t\"receivedFromRemoteAddress\": \"%s\""ZT_EOL_S
+		"\t\"timestamp\": %llu," ZT_EOL_S
+		"\t\"testId\": \"%.16llx\"," ZT_EOL_S
+		"\t\"upstream\": \"%.10llx\"," ZT_EOL_S
+		"\t\"current\": \"%.10llx\"," ZT_EOL_S
+		"\t\"receivedTimestamp\": %llu," ZT_EOL_S
+		"\t\"remoteTimestamp\": %llu," ZT_EOL_S
+		"\t\"sourcePacketId\": \"%.16llx\"," ZT_EOL_S
+		"\t\"flags\": %llu," ZT_EOL_S
+		"\t\"sourcePacketHopCount\": %u," ZT_EOL_S
+		"\t\"errorCode\": %u," ZT_EOL_S
+		"\t\"vendor\": %d," ZT_EOL_S
+		"\t\"protocolVersion\": %u," ZT_EOL_S
+		"\t\"majorVersion\": %u," ZT_EOL_S
+		"\t\"minorVersion\": %u," ZT_EOL_S
+		"\t\"revision\": %u," ZT_EOL_S
+		"\t\"platform\": %d," ZT_EOL_S
+		"\t\"architecture\": %d," ZT_EOL_S
+		"\t\"receivedOnLocalAddress\": \"%s\"," ZT_EOL_S
+		"\t\"receivedFromRemoteAddress\": \"%s\"" ZT_EOL_S
 		"}",
 		((cte->second.jsonResults.length() > 0) ? ",\n" : ""),
 		(unsigned long long)report->timestamp,
diff --git a/controller/SqliteNetworkController.hpp b/controller/SqliteNetworkController.hpp
index 0d549abc..15e0968f 100644
--- a/controller/SqliteNetworkController.hpp
+++ b/controller/SqliteNetworkController.hpp
@@ -14,15 +14,6 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- * --
- *
- * ZeroTier may be used and distributed under the terms of the GPLv3, which
- * are available at: http://www.gnu.org/licenses/gpl-3.0.html
- *
- * If you would like to embed ZeroTier into a commercial application or
- * redistribute it in a modified binary form, please contact ZeroTier Networks
- * LLC. Start here: http://www.zerotier.com/
  */
 
 #ifndef ZT_SQLITENETWORKCONTROLLER_HPP
@@ -38,9 +29,11 @@
 
 #include "../node/NetworkController.hpp"
 #include "../node/Mutex.hpp"
-#include "../osdep/Thread.hpp"
+#include "../node/Utils.hpp"
+
+#include "../osdep/OSUtils.hpp"
 
-#include "../ext/offbase/offbase.hpp"
+#include "../ext/json/json.hpp"
 
 namespace ZeroTier {
 
@@ -82,10 +75,6 @@ public:
 		std::string &responseBody,
 		std::string &responseContentType);
 
-	// threadMain() for backup thread -- do not call directly
-	void threadMain()
-		throw();
-
 private:
 	unsigned int _doCPGet(
 		const std::vector<std::string> &path,
@@ -97,11 +86,57 @@ private:
 
 	static void _circuitTestCallback(ZT_Node *node,ZT_CircuitTest *test,const ZT_CircuitTestReport *report);
 
+	inline nlohmann::json _readJson(const std::string &path)
+	{
+		std::string buf;
+		if (OSUtils::readFile(path.c_str(),buf)) {
+			try {
+				return nlohmann::json::parse(buf);
+			} catch ( ... ) {}
+		}
+		return nlohmann::json::object();
+	}
+
+	inline bool _writeJson(const std::string &path,const nlohmann::json &obj)
+	{
+		std::string buf(obj.dump(2));
+		return OSUtils::writeFile(path.c_str(),buf);
+	}
+
+	inline std::string _networkBP(const uint64_t nwid,bool create)
+	{
+		char tmp[64];
+		Utils::snprintf(tmp,sizeof(tmp),"%.16llx",nwid);
+		std::string p(_path + ZT_PATH_SEPARATOR_S + "network");
+		if (create) OSUtils::mkdir(p.c_str());
+		p.push_back(ZT_PATH_SEPARATOR);
+		p.append(tmp);
+		if (create) OSUtils::mkdir(p.c_str());
+		return p;
+	}
+	inline std::string _networkJP(const uint64_t nwid,bool create)
+	{
+		return (_networkBP(nwid,create) + ZT_PATH_SEPARATOR + "config.json");
+	}
+	inline std::string _memberBP(const uint64_t nwid,const Address &member,bool create)
+	{
+		std::string p(_networkBP(nwid,create));
+		p.push_back(ZT_PATH_SEPARATOR);
+		p.append("member");
+		if (create) OSUtils::mkdir(p.c_str());
+		p.push_back(ZT_PATH_SEPARATOR);
+		p.append(member.toString());
+		if (create) OSUtils::mkdir(p.c_str());
+		return p;
+	}
+	inline std::string _memberJP(const uint64_t nwid,const Address &member,bool create)
+	{
+		return (_memberBP(nwid,member,create) + ZT_PATH_SEPARATOR + "config.json");
+	}
+
+	// These are const after construction
 	Node *const _node;
-	std::string _instanceId;
-	offbase _db;
-	Thread _dbCommitThread;
-	volatile bool _dbCommitThreadRun;
+	std::string _path;
 
 	// Circuit tests outstanding
 	struct _CircuitTestEntry
@@ -110,11 +145,11 @@ private:
 		std::string jsonResults;
 	};
 	std::map< uint64_t,_CircuitTestEntry > _circuitTests;
+	Mutex _circuitTests_m;
 
 	// Last request time by address, for rate limitation
 	std::map< std::pair<uint64_t,uint64_t>,uint64_t > _lastRequestTime;
-
-	Mutex _lock;
+	Mutex _lastRequestTime_m;
 };
 
 } // namespace ZeroTier
diff --git a/ext/json/LICENSE.MIT b/ext/json/LICENSE.MIT
new file mode 100644
index 00000000..e2ac4891
--- /dev/null
+++ b/ext/json/LICENSE.MIT
@@ -0,0 +1,22 @@
+The library is licensed under the MIT License 
+<http://opensource.org/licenses/MIT>:
+
+Copyright (c) 2013-2016 Niels Lohmann
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/ext/json/README.md b/ext/json/README.md
new file mode 100644
index 00000000..c0bb61b1
--- /dev/null
+++ b/ext/json/README.md
@@ -0,0 +1,511 @@
+[![JSON for Modern C++](https://raw.githubusercontent.com/nlohmann/json/master/doc/json.gif)](https://github.com/nlohmann/json/releases)
+
+[![Build Status](https://travis-ci.org/nlohmann/json.svg?branch=master)](https://travis-ci.org/nlohmann/json)
+[![Build Status](https://ci.appveyor.com/api/projects/status/1acb366xfyg3qybk?svg=true)](https://ci.appveyor.com/project/nlohmann/json)
+[![Coverage Status](https://img.shields.io/coveralls/nlohmann/json.svg)](https://coveralls.io/r/nlohmann/json)
+[![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
+[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/p5o4znPnGHJpDVqN)
+[![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](http://nlohmann.github.io/json)
+[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
+[![Github Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
+[![Github Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](http://github.com/nlohmann/json/issues)
+
+## Design goals
+
+There are myriads of [JSON](http://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
+
+- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you know, what I mean.
+
+- **Trivial integration**. Our whole code consists of a single header file [`json.hpp`](https://github.com/nlohmann/json/blob/develop/src/json.hpp). That's it. No library, no subproject, no dependencies, no complex build system. The class is written in vanilla C++11. All in all, everything should require no adjustment of your compiler flags or project settings.
+
+- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/blob/master/test/src/unit.cpp) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) that there are no memory leaks.
+
+Other aspects were not so important to us:
+
+- **Memory efficiency**. Each JSON object has an overhead of one pointer (the maximal size of a union) and one enumeration element (1 byte). The default generalization uses the following C++ data types: `std::string` for strings, `int64_t`, `uint64_t` or `double` for numbers, `std::map` for objects, `std::vector` for arrays, and `bool` for Booleans. However, you can template the generalized class `basic_json` to your needs.
+
+- **Speed**. We currently implement the parser as naive [recursive descent parser](http://en.wikipedia.org/wiki/Recursive_descent_parser) with hand coded string handling. It is fast enough, but a [LALR-parser](http://en.wikipedia.org/wiki/LALR_parser) may be even faster (but would consist of more files which makes the integration harder).
+
+See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.github/CONTRIBUTING.md#please-dont) for more information.
+
+
+## Integration
+
+The single required source, file `json.hpp` is in the `src` directory or [released here](https://github.com/nlohmann/json/releases). All you need to do is add
+
+```cpp
+#include "json.hpp"
+
+// for convenience
+using json = nlohmann::json;
+```
+
+to the files you want to use JSON objects. That's it. Do not forget to set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).
+
+:beer: If you are using OS X and [Homebrew](http://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann_json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann_json --HEAD`.
+
+
+## Examples
+
+Here are some examples to give you an idea how to use the class.
+
+Assume you want to create the JSON object
+
+```json
+{
+  "pi": 3.141,
+  "happy": true,
+  "name": "Niels",
+  "nothing": null,
+  "answer": {
+    "everything": 42
+  },
+  "list": [1, 0, 2],
+  "object": {
+    "currency": "USD",
+    "value": 42.99
+  }
+}
+```
+
+With the JSON class, you could write:
+
+```cpp
+// create an empty structure (null)
+json j;
+
+// add a number that is stored as double (note the implicit conversion of j to an object)
+j["pi"] = 3.141;
+
+// add a Boolean that is stored as bool
+j["happy"] = true;
+
+// add a string that is stored as std::string
+j["name"] = "Niels";
+
+// add another null object by passing nullptr
+j["nothing"] = nullptr;
+
+// add an object inside the object
+j["answer"]["everything"] = 42;
+
+// add an array that is stored as std::vector (using an initializer list)
+j["list"] = { 1, 0, 2 };
+
+// add another object (using an initializer list of pairs)
+j["object"] = { {"currency", "USD"}, {"value", 42.99} };
+
+// instead, you could also write (which looks very similar to the JSON above)
+json j2 = {
+  {"pi", 3.141},
+  {"happy", true},
+  {"name", "Niels"},
+  {"nothing", nullptr},
+  {"answer", {
+    {"everything", 42}
+  }},
+  {"list", {1, 0, 2}},
+  {"object", {
+    {"currency", "USD"},
+    {"value", 42.99}
+  }}
+};
+```
+
+Note that in all these cases, you never need to "tell" the compiler which JSON value you want to use. If you want to be explicit or express some edge cases, the functions `json::array` and `json::object` will help:
+
+```cpp
+// a way to express the empty array []
+json empty_array_explicit = json::array();
+
+// ways to express the empty object {}
+json empty_object_implicit = json({});
+json empty_object_explicit = json::object();
+
+// a way to express an _array_ of key/value pairs [["currency", "USD"], ["value", 42.99]]
+json array_not_object = { json::array({"currency", "USD"}), json::array({"value", 42.99}) };
+```
+
+
+### Serialization / Deserialization
+
+You can create an object (deserialization) by appending `_json` to a string literal:
+
+```cpp
+// create object from string literal
+json j = "{ \"happy\": true, \"pi\": 3.141 }"_json;
+
+// or even nicer with a raw string literal
+auto j2 = R"(
+  {
+    "happy": true,
+    "pi": 3.141
+  }
+)"_json;
+
+// or explicitly
+auto j3 = json::parse("{ \"happy\": true, \"pi\": 3.141 }");
+```
+
+You can also get a string representation (serialize):
+
+```cpp
+// explicit conversion to string
+std::string s = j.dump();    // {\"happy\":true,\"pi\":3.141}
+
+// serialization with pretty printing
+// pass in the amount of spaces to indent
+std::cout << j.dump(4) << std::endl;
+// {
+//     "happy": true,
+//     "pi": 3.141
+// }
+```
+
+You can also use streams to serialize and deserialize:
+
+```cpp
+// deserialize from standard input
+json j;
+std::cin >> j;
+
+// serialize to standard output
+std::cout << j;
+
+// the setw manipulator was overloaded to set the indentation for pretty printing
+std::cout << std::setw(4) << j << std::endl;
+```
+
+These operators work for any subclasses of `std::istream` or `std::ostream`.
+
+Please note that setting the exception bit for `failbit` is inappropriate for this use case. It will result in program termination due to the `noexcept` specifier in use.
+
+
+### STL-like access
+
+We designed the JSON class to behave just like an STL container. In fact, it satisfies the [**ReversibleContainer**](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) requirement.
+
+```cpp
+// create an array using push_back
+json j;
+j.push_back("foo");
+j.push_back(1);
+j.push_back(true);
+
+// iterate the array
+for (json::iterator it = j.begin(); it != j.end(); ++it) {
+  std::cout << *it << '\n';
+}
+
+// range-based for
+for (auto& element : j) {
+  std::cout << element << '\n';
+}
+
+// getter/setter
+const std::string tmp = j[0];
+j[1] = 42;
+bool foo = j.at(2);
+
+// other stuff
+j.size();     // 3 entries
+j.empty();    // false
+j.type();     // json::value_t::array
+j.clear();    // the array is empty again
+
+// convenience type checkers
+j.is_null();
+j.is_boolean();
+j.is_number();
+j.is_object();
+j.is_array();
+j.is_string();
+
+// comparison
+j == "[\"foo\", 1, true]"_json;  // true
+
+// create an object
+json o;
+o["foo"] = 23;
+o["bar"] = false;
+o["baz"] = 3.141;
+
+// special iterator member functions for objects
+for (json::iterator it = o.begin(); it != o.end(); ++it) {
+  std::cout << it.key() << " : " << it.value() << "\n";
+}
+
+// find an entry
+if (o.find("foo") != o.end()) {
+  // there is an entry with key "foo"
+}
+
+// or simpler using count()
+int foo_present = o.count("foo"); // 1
+int fob_present = o.count("fob"); // 0
+
+// delete an entry
+o.erase("foo");
+```
+
+
+### Conversion from STL containers
+
+Any sequence container (`std::array`, `std::vector`, `std::deque`, `std::forward_list`, `std::list`) whose values can be used to construct JSON types (e.g., integers, floating point numbers, Booleans, string types, or again STL containers described in this section) can be used to create a JSON array. The same holds for similar associative containers (`std::set`, `std::multiset`, `std::unordered_set`, `std::unordered_multiset`), but in these cases the order of the elements of the array depends how the elements are ordered in the respective STL container.
+
+```cpp
+std::vector<int> c_vector {1, 2, 3, 4};
+json j_vec(c_vector);
+// [1, 2, 3, 4]
+
+std::deque<double> c_deque {1.2, 2.3, 3.4, 5.6};
+json j_deque(c_deque);
+// [1.2, 2.3, 3.4, 5.6]
+
+std::list<bool> c_list {true, true, false, true};
+json j_list(c_list);
+// [true, true, false, true]
+
+std::forward_list<int64_t> c_flist {12345678909876, 23456789098765, 34567890987654, 45678909876543};
+json j_flist(c_flist);
+// [12345678909876, 23456789098765, 34567890987654, 45678909876543]
+
+std::array<unsigned long, 4> c_array {{1, 2, 3, 4}};
+json j_array(c_array);
+// [1, 2, 3, 4]
+
+std::set<std::string> c_set {"one", "two", "three", "four", "one"};
+json j_set(c_set); // only one entry for "one" is used
+// ["four", "one", "three", "two"]
+
+std::unordered_set<std::string> c_uset {"one", "two", "three", "four", "one"};
+json j_uset(c_uset); // only one entry for "one" is used
+// maybe ["two", "three", "four", "one"]
+
+std::multiset<std::string> c_mset {"one", "two", "one", "four"};
+json j_mset(c_mset); // only one entry for "one" is used
+// maybe ["one", "two", "four"]
+
+std::unordered_multiset<std::string> c_umset {"one", "two", "one", "four"};
+json j_umset(c_umset); // both entries for "one" are used
+// maybe ["one", "two", "one", "four"]
+```
+
+Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON types (see examples above) can be used to to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
+
+```cpp
+std::map<std::string, int> c_map { {"one", 1}, {"two", 2}, {"three", 3} };
+json j_map(c_map);
+// {"one": 1, "three": 3, "two": 2 }
+
+std::unordered_map<const char*, double> c_umap { {"one", 1.2}, {"two", 2.3}, {"three", 3.4} };
+json j_umap(c_umap);
+// {"one": 1.2, "two": 2.3, "three": 3.4}
+
+std::multimap<std::string, bool> c_mmap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
+json j_mmap(c_mmap); // only one entry for key "three" is used
+// maybe {"one": true, "two": true, "three": true}
+
+std::unordered_multimap<std::string, bool> c_ummap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
+json j_ummap(c_ummap); // only one entry for key "three" is used
+// maybe {"one": true, "two": true, "three": true}
+```
+
+### JSON Pointer and JSON Patch
+
+The library supports **JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) as alternative means to address structured values. On top of this, **JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) allows to describe differences between two JSON values - effectively allowing patch and diff operations known from Unix.
+
+```cpp
+// a JSON value
+json j_original = R"({
+  "baz": ["one", "two", "three"],
+  "foo": "bar"
+})"_json;
+
+// access members with a JSON pointer (RFC 6901)
+j_original["/baz/1"_json_pointer];
+// "two"
+
+// a JSON patch (RFC 6902)
+json j_patch = R"([
+  { "op": "replace", "path": "/baz", "value": "boo" },
+  { "op": "add", "path": "/hello", "value": ["world"] },
+  { "op": "remove", "path": "/foo"}
+])"_json;
+
+// apply the patch
+json j_result = j_original.patch(j_patch);
+// {
+//    "baz": "boo",
+//    "hello": ["world"]
+// }
+
+// calculate a JSON patch from two JSON values
+json::diff(j_result, j_original);
+// [
+//   { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] },
+//   { "op": "remove","path": "/hello" },
+//   { "op": "add", "path": "/foo", "value": "bar" }
+// ]
+```
+
+
+### Implicit conversions
+
+The type of the JSON object is determined automatically by the expression to store. Likewise, the stored value is implicitly converted.
+
+```cpp
+// strings
+std::string s1 = "Hello, world!";
+json js = s1;
+std::string s2 = js;
+
+// Booleans
+bool b1 = true;
+json jb = b1;
+bool b2 = jb;
+
+// numbers
+int i = 42;
+json jn = i;
+double f = jn;
+
+// etc.
+```
+
+You can also explicitly ask for the value:
+
+```cpp
+std::string vs = js.get<std::string>();
+bool vb = jb.get<bool>();
+int vi = jn.get<int>();
+
+// etc.
+```
+
+
+## Supported compilers
+
+Though it's 2016 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
+
+- GCC 4.9 - 6.0 (and possibly later)
+- Clang 3.4 - 3.9 (and possibly later)
+- Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
+
+I would be happy to learn about other compilers/versions.
+
+Please note:
+
+- GCC 4.8 does not work because of two bugs ([55817](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55817) and [57824](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57824)) in the C++11 support. Note there is a [pull request](https://github.com/nlohmann/json/pull/212) to fix some of the issues.
+- Android defaults to using very old compilers and C++ libraries. To fix this, add the following to your `Application.mk`. This will switch to the LLVM C++ library, the Clang compiler, and enable C++11 and other features disabled by default.
+ 
+    ```
+    APP_STL := c++_shared
+    NDK_TOOLCHAIN_VERSION := clang3.6
+    APP_CPPFLAGS += -frtti -fexceptions
+    ```
+ 
+    The code compiles successfully with [Android NDK](https://developer.android.com/ndk/index.html?hl=ml), Revision 9 - 11 (and possibly later) and [CrystaX's Android NDK](https://www.crystax.net/en/android/ndk) version 10.
+
+- For GCC running on MinGW or Android SDK, the error `'to_string' is not a member of 'std'` (or similarly, for `strtod`) may occur. Note this is not an issue with the code,  but rather with the compiler itself. On Android, see above to build with a newer environment.  For MinGW, please refer to [this site](http://tehsausage.com/mingw-to-string) and [this discussion](https://github.com/nlohmann/json/issues/136) for information on how to fix this bug. For Android NDK using `APP_STL := gnustl_static`, please refer to [this discussion](https://github.com/nlohmann/json/issues/219).
+
+The following compilers are currently used in continuous integration at [Travis](https://travis-ci.org/nlohmann/json) and [AppVeyor](https://ci.appveyor.com/project/nlohmann/json):
+
+| Compiler        | Operating System             | Version String |
+|-----------------|------------------------------|----------------|
+| GCC 4.9.3       | Ubuntu 14.04.4 LTS           | g++-4.9 (Ubuntu 4.9.3-8ubuntu2~14.04) 4.9.3 |
+| GCC 5.3.0       | Ubuntu 14.04.4 LTS           | g++-5 (Ubuntu 5.3.0-3ubuntu1~14.04) 5.3.0 20151204 |
+| GCC 6.1.1       | Ubuntu 14.04.4 LTS           | g++-6 (Ubuntu 6.1.1-3ubuntu11~14.04.1) 6.1.1 20160511 |
+| Clang 3.8.0     | Ubuntu 14.04.4 LTS           | clang version 3.8.0 (tags/RELEASE_380/final) |
+| Clang Xcode 6.1 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) |
+| Clang Xcode 6.2 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) |
+| Clang Xcode 6.3 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn) |
+| Clang Xcode 6.4 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn) |
+| Clang Xcode 7.1 | Darwin Kernel Version 14.5.0 (OSX 10.10.5) | Apple LLVM version 7.0.0 (clang-700.1.76) |
+| Clang Xcode 7.2 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.0.2 (clang-700.1.81) |
+| Clang Xcode 7.3 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.3.0 (clang-703.0.29) |
+| Clang Xcode 8.0 | Darwin Kernel Version 15.5.0 (OSX 10.11.5) | Apple LLVM version 8.0.0 (clang-800.0.24.1) |
+| Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25123.0 | 
+
+
+## License
+
+<img align="right" src="http://opensource.org/trademarks/opensource/OSI-Approved-License-100x137.png">
+
+The class is licensed under the [MIT License](http://opensource.org/licenses/MIT):
+
+Copyright &copy; 2013-2016 [Niels Lohmann](http://nlohmann.me)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+## Thanks
+
+I deeply appreciate the help of the following people.
+
+- [Teemperor](https://github.com/Teemperor) implemented CMake support and lcov integration, realized escape and Unicode handling in the string parser, and fixed the JSON serialization.
+- [elliotgoodrich](https://github.com/elliotgoodrich) fixed an issue with double deletion in the iterator classes.
+- [kirkshoop](https://github.com/kirkshoop) made the iterators of the class composable to other libraries.
+- [wancw](https://github.com/wanwc) fixed a bug that hindered the class to compile with Clang.
+- Tomas Åblad found a bug in the iterator implementation.
+- [Joshua C. Randall](https://github.com/jrandall) fixed a bug in the floating-point serialization.
+- [Aaron Burghardt](https://github.com/aburgh) implemented code to parse streams incrementally. Furthermore, he greatly improved the parser class by allowing the definition of a filter function to discard undesired elements while parsing.
+- [Daniel Kopeček](https://github.com/dkopecek) fixed a bug in the compilation with GCC 5.0.
+- [Florian Weber](https://github.com/Florianjw) fixed a bug in and improved the performance of the comparison operators.
+- [Eric Cornelius](https://github.com/EricMCornelius) pointed out a bug in the handling with NaN and infinity values. He also improved the performance of the string escaping.
+- [易思龙](https://github.com/likebeta) implemented a conversion from anonymous enums.
+- [kepkin](https://github.com/kepkin) patiently pushed forward the support for Microsoft Visual studio.
+- [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators and helped with numerous hints and improvements.
+- [Caio Luppi](https://github.com/caiovlp) fixed a bug in the Unicode handling.
+- [dariomt](https://github.com/dariomt) fixed some typos in the examples.
+- [Daniel Frey](https://github.com/d-frey) cleaned up some pointers and implemented exception-safe memory allocation.
+- [Colin Hirsch](https://github.com/ColinH) took care of a small namespace issue.
+- [Huu Nguyen](https://github.com/whoshuu) correct a variable name in the documentation.
+- [Silverweed](https://github.com/silverweed) overloaded `parse()` to accept an rvalue reference.
+- [dariomt](https://github.com/dariomt) fixed a subtlety in MSVC type support and implemented the `get_ref()` function to get a reference to stored values.
+- [ZahlGraf](https://github.com/ZahlGraf) added a workaround that allows compilation using Android NDK.
+- [whackashoe](https://github.com/whackashoe) replaced a function that was marked as unsafe by Visual Studio.
+- [406345](https://github.com/406345) fixed two small warnings.
+- [Glen Fernandes](https://github.com/glenfe) noted a potential portability problem in the `has_mapped_type` function.
+- [Corbin Hughes](https://github.com/nibroc) fixed some typos in the contribution guidelines.
+- [twelsby](https://github.com/twelsby) fixed the array subscript operator, an issue that failed the MSVC build, and floating-point parsing/dumping. He further added support for unsigned integer numbers and implemented better roundtrip support for parsed numbers.
+- [Volker Diels-Grabsch](https://github.com/vog) fixed a link in the README file.
+- [msm-](https://github.com/msm-) added support for american fuzzy lop. 
+- [Annihil](https://github.com/Annihil) fixed an example in the README file.
+- [Themercee](https://github.com/Themercee) noted a wrong URL in the README file.
+- [Lv Zheng](https://github.com/lv-zheng) fixed a namespace issue with `int64_t` and `uint64_t`.
+- [abc100m](https://github.com/abc100m) analyzed the issues with GCC 4.8 and proposed a [partial solution](https://github.com/nlohmann/json/pull/212).
+- [zewt](https://github.com/zewt) added useful notes to the README file about Android.
+- [Róbert Márki](https://github.com/robertmrk) added a fix to use move iterators and improved the integration via CMake.
+- [Chris Kitching](https://github.com/ChrisKitching) cleaned up the CMake files.
+- [Tom Needham](https://github.com/06needhamt) fixed a subtle bug with MSVC 2015 which was also proposed by [Michael K.](https://github.com/Epidal).
+- [Mário Feroldi](https://github.com/thelostt) fixed a small typo.
+- [duncanwerner](https://github.com/duncanwerner) found a really embarrassing performance regression in the 2.0.0 release.
+- [Damien](https://github.com/dtoma) fixed one of the last conversion warnings.
+
+Thanks a lot for helping out!
+
+
+## Notes
+
+- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](http://en.cppreference.com/w/cpp/error/assert).
+- As the exact type of a number is not defined in the [JSON specification](http://rfc7159.net/rfc7159), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
+
+
+## Execute unit tests
+
+To compile and run the tests, you need to execute
+
+```sh
+$ make
+$ ./json_unit "*"
+
+===============================================================================
+All tests passed (8905012 assertions in 32 test cases)
+```
+
+For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).
diff --git a/ext/json/json.hpp b/ext/json/json.hpp
new file mode 100644
index 00000000..878fb899
--- /dev/null
+++ b/ext/json/json.hpp
@@ -0,0 +1,10435 @@
+/*
+    __ _____ _____ _____
+ __|  |   __|     |   | |  JSON for Modern C++
+|  |  |__   |  |  | | | |  version 2.0.2
+|_____|_____|_____|_|___|  https://github.com/nlohmann/json
+
+Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+Copyright (c) 2013-2016 Niels Lohmann <http://nlohmann.me>.
+
+Permission is hereby  granted, free of charge, to any  person obtaining a copy
+of this software and associated  documentation files (the "Software"), to deal
+in the Software  without restriction, including without  limitation the rights
+to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
+copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
+IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
+FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
+AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
+LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#ifndef NLOHMANN_JSON_HPP
+#define NLOHMANN_JSON_HPP
+
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <ciso646>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <functional>
+#include <initializer_list>
+#include <iomanip>
+#include <iostream>
+#include <iterator>
+#include <limits>
+#include <locale>
+#include <map>
+#include <memory>
+#include <numeric>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+// exclude unsupported compilers
+#if defined(__clang__)
+    #define CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
+    #if CLANG_VERSION < 30400
+        #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
+    #endif
+#elif defined(__GNUC__)
+    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
+    #if GCC_VERSION < 40900
+        #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
+    #endif
+#endif
+
+// disable float-equal warnings on GCC/clang
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+
+/*!
+@brief namespace for Niels Lohmann
+@see https://github.com/nlohmann
+@since version 1.0.0
+*/
+namespace nlohmann
+{
+
+
+/*!
+@brief unnamed namespace with internal helper functions
+@since version 1.0.0
+*/
+namespace
+{
+/*!
+@brief Helper to determine whether there's a key_type for T.
+
+Thus helper is used to tell associative containers apart from other containers
+such as sequence containers. For instance, `std::map` passes the test as it
+contains a `mapped_type`, whereas `std::vector` fails the test.
+
+@sa http://stackoverflow.com/a/7728728/266378
+@since version 1.0.0
+*/
+template<typename T>
+struct has_mapped_type
+{
+  private:
+    template<typename C> static char test(typename C::mapped_type*);
+    template<typename C> static char (&test(...))[2];
+  public:
+    static constexpr bool value = sizeof(test<T>(0)) == 1;
+};
+
+/*!
+@brief helper class to create locales with decimal point
+
+This struct is used a default locale during the JSON serialization. JSON
+requires the decimal point to be `.`, so this function overloads the
+`do_decimal_point()` function to return `.`. This function is called by
+float-to-string conversions to retrieve the decimal separator between integer
+and fractional parts.
+
+@sa https://github.com/nlohmann/json/issues/51#issuecomment-86869315
+@since version 2.0.0
+*/
+struct DecimalSeparator : std::numpunct<char>
+{
+    char do_decimal_point() const
+    {
+        return '.';
+    }
+};
+
+}
+
+/*!
+@brief a class to store JSON values
+
+@tparam ObjectType type for JSON objects (`std::map` by default; will be used
+in @ref object_t)
+@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
+in @ref array_t)
+@tparam StringType type for JSON strings and object keys (`std::string` by
+default; will be used in @ref string_t)
+@tparam BooleanType type for JSON booleans (`bool` by default; will be used
+in @ref boolean_t)
+@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
+default; will be used in @ref number_integer_t)
+@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
+`uint64_t` by default; will be used in @ref number_unsigned_t)
+@tparam NumberFloatType type for JSON floating-point numbers (`double` by
+default; will be used in @ref number_float_t)
+@tparam AllocatorType type of the allocator to use (`std::allocator` by
+default)
+
+@requirement The class satisfies the following concept requirements:
+- Basic
+ - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
+   JSON values can be default constructed. The result will be a JSON null value.
+ - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
+   A JSON value can be constructed from an rvalue argument.
+ - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
+   A JSON value can be copy-constructed from an lvalue expression.
+ - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
+   A JSON value van be assigned from an rvalue argument.
+ - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
+   A JSON value can be copy-assigned from an lvalue expression.
+ - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
+   JSON values can be destructed.
+- Layout
+ - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
+   JSON values have
+   [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
+   All non-static data members are private and standard layout types, the class
+   has no virtual functions or (virtual) base classes.
+- Library-wide
+ - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
+   JSON values can be compared with `==`, see @ref
+   operator==(const_reference,const_reference).
+ - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
+   JSON values can be compared with `<`, see @ref
+   operator<(const_reference,const_reference).
+ - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
+   Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
+   other compatible types, using unqualified function call @ref swap().
+ - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
+   JSON values can be compared against `std::nullptr_t` objects which are used
+   to model the `null` value.
+- Container
+ - [Container](http://en.cppreference.com/w/cpp/concept/Container):
+   JSON values can be used like STL containers and provide iterator access.
+ - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
+   JSON values can be used like STL containers and provide reverse iterator
+   access.
+
+@invariant The member variables @a m_value and @a m_type have the following
+relationship:
+- If `m_type == value_t::object`, then `m_value.object != nullptr`.
+- If `m_type == value_t::array`, then `m_value.array != nullptr`.
+- If `m_type == value_t::string`, then `m_value.string != nullptr`.
+The invariants are checked by member function assert_invariant().
+
+@internal
+@note ObjectType trick from http://stackoverflow.com/a/9860911
+@endinternal
+
+@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
+Format](http://rfc7159.net/rfc7159)
+
+@since version 1.0.0
+
+@nosubgrouping
+*/
+template <
+    template<typename U, typename V, typename... Args> class ObjectType = std::map,
+    template<typename U, typename... Args> class ArrayType = std::vector,
+    class StringType = std::string,
+    class BooleanType = bool,
+    class NumberIntegerType = std::int64_t,
+    class NumberUnsignedType = std::uint64_t,
+    class NumberFloatType = double,
+    template<typename U> class AllocatorType = std::allocator
+    >
+class basic_json
+{
+  private:
+    /// workaround type for MSVC
+    using basic_json_t = basic_json<ObjectType, ArrayType, StringType,
+          BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType,
+          AllocatorType>;
+
+  public:
+    // forward declarations
+    template<typename Base> class json_reverse_iterator;
+    class json_pointer;
+
+    /////////////////////
+    // container types //
+    /////////////////////
+
+    /// @name container types
+    /// The canonic container types to use @ref basic_json like any other STL
+    /// container.
+    /// @{
+
+    /// the type of elements in a basic_json container
+    using value_type = basic_json;
+
+    /// the type of an element reference
+    using reference = value_type&;
+    /// the type of an element const reference
+    using const_reference = const value_type&;
+
+    /// a type to represent differences between iterators
+    using difference_type = std::ptrdiff_t;
+    /// a type to represent container sizes
+    using size_type = std::size_t;
+
+    /// the allocator type
+    using allocator_type = AllocatorType<basic_json>;
+
+    /// the type of an element pointer
+    using pointer = typename std::allocator_traits<allocator_type>::pointer;
+    /// the type of an element const pointer
+    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
+
+    /// an iterator for a basic_json container
+    class iterator;
+    /// a const iterator for a basic_json container
+    class const_iterator;
+    /// a reverse iterator for a basic_json container
+    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
+    /// a const reverse iterator for a basic_json container
+    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;
+
+    /// @}
+
+
+    /*!
+    @brief returns the allocator associated with the container
+    */
+    static allocator_type get_allocator()
+    {
+        return allocator_type();
+    }
+
+
+    ///////////////////////////
+    // JSON value data types //
+    ///////////////////////////
+
+    /// @name JSON value data types
+    /// The data types to store a JSON value. These types are derived from
+    /// the template arguments passed to class @ref basic_json.
+    /// @{
+
+    /*!
+    @brief a type for an object
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
+    > An object is an unordered collection of zero or more name/value pairs,
+    > where a name is a string and a value is a string, number, boolean, null,
+    > object, or array.
+
+    To store objects in C++, a type is defined by the template parameters
+    described below.
+
+    @tparam ObjectType  the container to store objects (e.g., `std::map` or
+    `std::unordered_map`)
+    @tparam StringType the type of the keys or names (e.g., `std::string`).
+    The comparison function `std::less<StringType>` is used to order elements
+    inside the container.
+    @tparam AllocatorType the allocator to use for objects (e.g.,
+    `std::allocator`)
+
+    #### Default type
+
+    With the default values for @a ObjectType (`std::map`), @a StringType
+    (`std::string`), and @a AllocatorType (`std::allocator`), the default
+    value for @a object_t is:
+
+    @code {.cpp}
+    std::map<
+      std::string, // key_type
+      basic_json, // value_type
+      std::less<std::string>, // key_compare
+      std::allocator<std::pair<const std::string, basic_json>> // allocator_type
+    >
+    @endcode
+
+    #### Behavior
+
+    The choice of @a object_t influences the behavior of the JSON class. With
+    the default type, objects have the following behavior:
+
+    - When all names are unique, objects will be interoperable in the sense
+      that all software implementations receiving that object will agree on
+      the name-value mappings.
+    - When the names within an object are not unique, later stored name/value
+      pairs overwrite previously stored name/value pairs, leaving the used
+      names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will
+      be treated as equal and both stored as `{"key": 1}`.
+    - Internally, name/value pairs are stored in lexicographical order of the
+      names. Objects will also be serialized (see @ref dump) in this order.
+      For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored
+      and serialized as `{"a": 2, "b": 1}`.
+    - When comparing objects, the order of the name/value pairs is irrelevant.
+      This makes objects interoperable in the sense that they will not be
+      affected by these differences. For instance, `{"b": 1, "a": 2}` and
+      `{"a": 2, "b": 1}` will be treated as equal.
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the maximum depth of nesting.
+
+    In this class, the object's limit of nesting is not constraint explicitly.
+    However, a maximum depth of nesting may be introduced by the compiler or
+    runtime environment. A theoretical limit can be queried by calling the
+    @ref max_size function of a JSON object.
+
+    #### Storage
+
+    Objects are stored as pointers in a @ref basic_json type. That is, for any
+    access to object values, a pointer of type `object_t*` must be
+    dereferenced.
+
+    @sa @ref array_t -- type for an array value
+
+    @since version 1.0.0
+
+    @note The order name/value pairs are added to the object is *not*
+    preserved by the library. Therefore, iterating an object may return
+    name/value pairs in a different order than they were originally stored. In
+    fact, keys will be traversed in alphabetical order as `std::map` with
+    `std::less` is used by default. Please note this behavior conforms to [RFC
+    7159](http://rfc7159.net/rfc7159), because any order implements the
+    specified "unordered" nature of JSON objects.
+    */
+    using object_t = ObjectType<StringType,
+          basic_json,
+          std::less<StringType>,
+          AllocatorType<std::pair<const StringType,
+          basic_json>>>;
+
+    /*!
+    @brief a type for an array
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
+    > An array is an ordered sequence of zero or more values.
+
+    To store objects in C++, a type is defined by the template parameters
+    explained below.
+
+    @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
+    `std::list`)
+    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
+
+    #### Default type
+
+    With the default values for @a ArrayType (`std::vector`) and @a
+    AllocatorType (`std::allocator`), the default value for @a array_t is:
+
+    @code {.cpp}
+    std::vector<
+      basic_json, // value_type
+      std::allocator<basic_json> // allocator_type
+    >
+    @endcode
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the maximum depth of nesting.
+
+    In this class, the array's limit of nesting is not constraint explicitly.
+    However, a maximum depth of nesting may be introduced by the compiler or
+    runtime environment. A theoretical limit can be queried by calling the
+    @ref max_size function of a JSON array.
+
+    #### Storage
+
+    Arrays are stored as pointers in a @ref basic_json type. That is, for any
+    access to array values, a pointer of type `array_t*` must be dereferenced.
+
+    @sa @ref object_t -- type for an object value
+
+    @since version 1.0.0
+    */
+    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
+
+    /*!
+    @brief a type for a string
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
+    > A string is a sequence of zero or more Unicode characters.
+
+    To store objects in C++, a type is defined by the template parameter
+    described below. Unicode values are split by the JSON class into
+    byte-sized characters during deserialization.
+
+    @tparam StringType  the container to store strings (e.g., `std::string`).
+    Note this container is used for keys/names in objects, see @ref object_t.
+
+    #### Default type
+
+    With the default values for @a StringType (`std::string`), the default
+    value for @a string_t is:
+
+    @code {.cpp}
+    std::string
+    @endcode
+
+    #### String comparison
+
+    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    > Software implementations are typically required to test names of object
+    > members for equality. Implementations that transform the textual
+    > representation into sequences of Unicode code units and then perform the
+    > comparison numerically, code unit by code unit, are interoperable in the
+    > sense that implementations will agree in all cases on equality or
+    > inequality of two strings. For example, implementations that compare
+    > strings with escaped characters unconverted may incorrectly find that
+    > `"a\\b"` and `"a\u005Cb"` are not equal.
+
+    This implementation is interoperable as it does compare strings code unit
+    by code unit.
+
+    #### Storage
+
+    String values are stored as pointers in a @ref basic_json type. That is,
+    for any access to string values, a pointer of type `string_t*` must be
+    dereferenced.
+
+    @since version 1.0.0
+    */
+    using string_t = StringType;
+
+    /*!
+    @brief a type for a boolean
+
+    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
+    type which differentiates the two literals `true` and `false`.
+
+    To store objects in C++, a type is defined by the template parameter @a
+    BooleanType which chooses the type to use.
+
+    #### Default type
+
+    With the default values for @a BooleanType (`bool`), the default value for
+    @a boolean_t is:
+
+    @code {.cpp}
+    bool
+    @endcode
+
+    #### Storage
+
+    Boolean values are stored directly inside a @ref basic_json type.
+
+    @since version 1.0.0
+    */
+    using boolean_t = BooleanType;
+
+    /*!
+    @brief a type for a number (integer)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
+
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
+
+    To store integer numbers in C++, a type is defined by the template
+    parameter @a NumberIntegerType which chooses the type to use.
+
+    #### Default type
+
+    With the default values for @a NumberIntegerType (`int64_t`), the default
+    value for @a number_integer_t is:
+
+    @code {.cpp}
+    int64_t
+    @endcode
+
+    #### Default behavior
+
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in integer literals lead to an interpretation as octal
+      number. Internally, the value will be stored as decimal number. For
+      instance, the C++ integer literal `010` will be serialized to `8`.
+      During deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the range and precision of numbers.
+
+    When the default type is used, the maximal integer number that can be
+    stored is `9223372036854775807` (INT64_MAX) and the minimal integer number
+    that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers
+    that are out of range will yield over/underflow when used in a
+    constructor. During deserialization, too large or small integer numbers
+    will be automatically be stored as @ref number_unsigned_t or @ref
+    number_float_t.
+
+    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    > Note that when such software is used, numbers that are integers and are
+    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
+    > that implementations will agree exactly on their numeric values.
+
+    As this range is a subrange of the exactly supported range [INT64_MIN,
+    INT64_MAX], this class's integer type is interoperable.
+
+    #### Storage
+
+    Integer number values are stored directly inside a @ref basic_json type.
+
+    @sa @ref number_float_t -- type for number values (floating-point)
+
+    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+
+    @since version 1.0.0
+    */
+    using number_integer_t = NumberIntegerType;
+
+    /*!
+    @brief a type for a number (unsigned)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
+
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
+
+    To store unsigned integer numbers in C++, a type is defined by the
+    template parameter @a NumberUnsignedType which chooses the type to use.
+
+    #### Default type
+
+    With the default values for @a NumberUnsignedType (`uint64_t`), the
+    default value for @a number_unsigned_t is:
+
+    @code {.cpp}
+    uint64_t
+    @endcode
+
+    #### Default behavior
+
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in integer literals lead to an interpretation as octal
+      number. Internally, the value will be stored as decimal number. For
+      instance, the C++ integer literal `010` will be serialized to `8`.
+      During deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the range and precision of numbers.
+
+    When the default type is used, the maximal integer number that can be
+    stored is `18446744073709551615` (UINT64_MAX) and the minimal integer
+    number that can be stored is `0`. Integer numbers that are out of range
+    will yield over/underflow when used in a constructor. During
+    deserialization, too large or small integer numbers will be automatically
+    be stored as @ref number_integer_t or @ref number_float_t.
+
+    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    > Note that when such software is used, numbers that are integers and are
+    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
+    > that implementations will agree exactly on their numeric values.
+
+    As this range is a subrange (when considered in conjunction with the
+    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
+    this class's integer type is interoperable.
+
+    #### Storage
+
+    Integer number values are stored directly inside a @ref basic_json type.
+
+    @sa @ref number_float_t -- type for number values (floating-point)
+    @sa @ref number_integer_t -- type for number values (integer)
+
+    @since version 2.0.0
+    */
+    using number_unsigned_t = NumberUnsignedType;
+
+    /*!
+    @brief a type for a number (floating-point)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
+
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
+
+    To store floating-point numbers in C++, a type is defined by the template
+    parameter @a NumberFloatType which chooses the type to use.
+
+    #### Default type
+
+    With the default values for @a NumberFloatType (`double`), the default
+    value for @a number_float_t is:
+
+    @code {.cpp}
+    double
+    @endcode
+
+    #### Default behavior
+
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in floating-point literals will be ignored. Internally,
+      the value will be stored as decimal number. For instance, the C++
+      floating-point literal `01.2` will be serialized to `1.2`. During
+      deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
+
+    #### Limits
+
+    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    > This specification allows implementations to set limits on the range and
+    > precision of numbers accepted. Since software that implements IEEE
+    > 754-2008 binary64 (double precision) numbers is generally available and
+    > widely used, good interoperability can be achieved by implementations
+    > that expect no more precision or range than these provide, in the sense
+    > that implementations will approximate JSON numbers within the expected
+    > precision.
+
+    This implementation does exactly follow this approach, as it uses double
+    precision floating-point numbers. Note values smaller than
+    `-1.79769313486232e+308` and values greater than `1.79769313486232e+308`
+    will be stored as NaN internally and be serialized to `null`.
+
+    #### Storage
+
+    Floating-point number values are stored directly inside a @ref basic_json
+    type.
+
+    @sa @ref number_integer_t -- type for number values (integer)
+
+    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+
+    @since version 1.0.0
+    */
+    using number_float_t = NumberFloatType;
+
+    /// @}
+
+
+    ///////////////////////////
+    // JSON type enumeration //
+    ///////////////////////////
+
+    /*!
+    @brief the JSON type enumeration
+
+    This enumeration collects the different JSON types. It is internally used
+    to distinguish the stored values, and the functions @ref is_null(), @ref
+    is_object(), @ref is_array(), @ref is_string(), @ref is_boolean(), @ref
+    is_number() (with @ref is_number_integer(), @ref is_number_unsigned(), and
+    @ref is_number_float()), @ref is_discarded(), @ref is_primitive(), and
+    @ref is_structured() rely on it.
+
+    @note There are three enumeration entries (number_integer,
+    number_unsigned, and number_float), because the library distinguishes
+    these three types for numbers: @ref number_unsigned_t is used for unsigned
+    integers, @ref number_integer_t is used for signed integers, and @ref
+    number_float_t is used for floating-point numbers or to approximate
+    integers which do not fit in the limits of their respective type.
+
+    @sa @ref basic_json(const value_t value_type) -- create a JSON value with
+    the default value for a given type
+
+    @since version 1.0.0
+    */
+    enum class value_t : uint8_t
+    {
+        null,            ///< null value
+        object,          ///< object (unordered set of name/value pairs)
+        array,           ///< array (ordered collection of values)
+        string,          ///< string value
+        boolean,         ///< boolean value
+        number_integer,  ///< number value (signed integer)
+        number_unsigned, ///< number value (unsigned integer)
+        number_float,    ///< number value (floating-point)
+        discarded        ///< discarded by the the parser callback function
+    };
+
+
+  private:
+
+    /// helper for exception-safe object creation
+    template<typename T, typename... Args>
+    static T* create(Args&& ... args)
+    {
+        AllocatorType<T> alloc;
+        auto deleter = [&](T * object)
+        {
+            alloc.deallocate(object, 1);
+        };
+        std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
+        alloc.construct(object.get(), std::forward<Args>(args)...);
+        assert(object.get() != nullptr);
+        return object.release();
+    }
+
+    ////////////////////////
+    // JSON value storage //
+    ////////////////////////
+
+    /*!
+    @brief a JSON value
+
+    The actual storage for a JSON value of the @ref basic_json class. This
+    union combines the different storage types for the JSON value types
+    defined in @ref value_t.
+
+    JSON type | value_t type    | used type
+    --------- | --------------- | ------------------------
+    object    | object          | pointer to @ref object_t
+    array     | array           | pointer to @ref array_t
+    string    | string          | pointer to @ref string_t
+    boolean   | boolean         | @ref boolean_t
+    number    | number_integer  | @ref number_integer_t
+    number    | number_unsigned | @ref number_unsigned_t
+    number    | number_float    | @ref number_float_t
+    null      | null            | *no value is stored*
+
+    @note Variable-length types (objects, arrays, and strings) are stored as
+    pointers. The size of the union should not exceed 64 bits if the default
+    value types are used.
+
+    @since version 1.0.0
+    */
+    union json_value
+    {
+        /// object (stored with pointer to save storage)
+        object_t* object;
+        /// array (stored with pointer to save storage)
+        array_t* array;
+        /// string (stored with pointer to save storage)
+        string_t* string;
+        /// boolean
+        boolean_t boolean;
+        /// number (integer)
+        number_integer_t number_integer;
+        /// number (unsigned integer)
+        number_unsigned_t number_unsigned;
+        /// number (floating-point)
+        number_float_t number_float;
+
+        /// default constructor (for null values)
+        json_value() = default;
+        /// constructor for booleans
+        json_value(boolean_t v) noexcept : boolean(v) {}
+        /// constructor for numbers (integer)
+        json_value(number_integer_t v) noexcept : number_integer(v) {}
+        /// constructor for numbers (unsigned)
+        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
+        /// constructor for numbers (floating-point)
+        json_value(number_float_t v) noexcept : number_float(v) {}
+        /// constructor for empty values of a given type
+        json_value(value_t t)
+        {
+            switch (t)
+            {
+                case value_t::object:
+                {
+                    object = create<object_t>();
+                    break;
+                }
+
+                case value_t::array:
+                {
+                    array = create<array_t>();
+                    break;
+                }
+
+                case value_t::string:
+                {
+                    string = create<string_t>("");
+                    break;
+                }
+
+                case value_t::boolean:
+                {
+                    boolean = boolean_t(false);
+                    break;
+                }
+
+                case value_t::number_integer:
+                {
+                    number_integer = number_integer_t(0);
+                    break;
+                }
+
+                case value_t::number_unsigned:
+                {
+                    number_unsigned = number_unsigned_t(0);
+                    break;
+                }
+
+                case value_t::number_float:
+                {
+                    number_float = number_float_t(0.0);
+                    break;
+                }
+
+                default:
+                {
+                    break;
+                }
+            }
+        }
+
+        /// constructor for strings
+        json_value(const string_t& value)
+        {
+            string = create<string_t>(value);
+        }
+
+        /// constructor for objects
+        json_value(const object_t& value)
+        {
+            object = create<object_t>(value);
+        }
+
+        /// constructor for arrays
+        json_value(const array_t& value)
+        {
+            array = create<array_t>(value);
+        }
+    };
+
+    /*!
+    @brief checks the class invariants
+
+    This function asserts the class invariants. It needs to be called at the
+    end of every constructor to make sure that created objects respect the
+    invariant. Furthermore, it has to be called each time the type of a JSON
+    value is changed, because the invariant expresses a relationship between
+    @a m_type and @a m_value.
+    */
+    void assert_invariant() const
+    {
+        assert(m_type != value_t::object or m_value.object != nullptr);
+        assert(m_type != value_t::array or m_value.array != nullptr);
+        assert(m_type != value_t::string or m_value.string != nullptr);
+    }
+
+  public:
+    //////////////////////////
+    // JSON parser callback //
+    //////////////////////////
+
+    /*!
+    @brief JSON callback events
+
+    This enumeration lists the parser events that can trigger calling a
+    callback function of type @ref parser_callback_t during parsing.
+
+    @image html callback_events.png "Example when certain parse events are triggered"
+
+    @since version 1.0.0
+    */
+    enum class parse_event_t : uint8_t
+    {
+        /// the parser read `{` and started to process a JSON object
+        object_start,
+        /// the parser read `}` and finished processing a JSON object
+        object_end,
+        /// the parser read `[` and started to process a JSON array
+        array_start,
+        /// the parser read `]` and finished processing a JSON array
+        array_end,
+        /// the parser read a key of a value in an object
+        key,
+        /// the parser finished reading a JSON value
+        value
+    };
+
+    /*!
+    @brief per-element parser callback type
+
+    With a parser callback function, the result of parsing a JSON text can be
+    influenced. When passed to @ref parse(std::istream&, const
+    parser_callback_t) or @ref parse(const string_t&, const parser_callback_t),
+    it is called on certain events (passed as @ref parse_event_t via parameter
+    @a event) with a set recursion depth @a depth and context JSON value
+    @a parsed. The return value of the callback function is a boolean
+    indicating whether the element that emitted the callback shall be kept or
+    not.
+
+    We distinguish six scenarios (determined by the event type) in which the
+    callback function can be called. The following table describes the values
+    of the parameters @a depth, @a event, and @a parsed.
+
+    parameter @a event | description | parameter @a depth | parameter @a parsed
+    ------------------ | ----------- | ------------------ | -------------------
+    parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded
+    parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key
+    parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object
+    parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded
+    parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
+    parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
+
+    @image html callback_events.png "Example when certain parse events are triggered"
+
+    Discarding a value (i.e., returning `false`) has different effects
+    depending on the context in which function was called:
+
+    - Discarded values in structured types are skipped. That is, the parser
+      will behave as if the discarded value was never read.
+    - In case a value outside a structured type is skipped, it is replaced
+      with `null`. This case happens if the top-level element is skipped.
+
+    @param[in] depth  the depth of the recursion during parsing
+
+    @param[in] event  an event of type parse_event_t indicating the context in
+    the callback function has been called
+
+    @param[in,out] parsed  the current intermediate parse result; note that
+    writing to this value has no effect for parse_event_t::key events
+
+    @return Whether the JSON value which called the function during parsing
+    should be kept (`true`) or not (`false`). In the latter case, it is either
+    skipped completely or replaced by an empty discarded object.
+
+    @sa @ref parse(std::istream&, parser_callback_t) or
+    @ref parse(const string_t&, parser_callback_t) for examples
+
+    @since version 1.0.0
+    */
+    using parser_callback_t = std::function<bool(int depth,
+                              parse_event_t event,
+                              basic_json& parsed)>;
+
+
+    //////////////////
+    // constructors //
+    //////////////////
+
+    /// @name constructors and destructors
+    /// Constructors of class @ref basic_json, copy/move constructor, copy
+    /// assignment, static functions creating objects, and the destructor.
+    /// @{
+
+    /*!
+    @brief create an empty value with a given type
+
+    Create an empty JSON value with a given type. The value will be default
+    initialized with an empty value which depends on the type:
+
+    Value type  | initial value
+    ----------- | -------------
+    null        | `null`
+    boolean     | `false`
+    string      | `""`
+    number      | `0`
+    object      | `{}`
+    array       | `[]`
+
+    @param[in] value_type  the type of the value to create
+
+    @complexity Constant.
+
+    @throw std::bad_alloc if allocation for object, array, or string value
+    fails
+
+    @liveexample{The following code shows the constructor for different @ref
+    value_t values,basic_json__value_t}
+
+    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
+    @sa @ref basic_json(boolean_t value) -- create a boolean value
+    @sa @ref basic_json(const string_t&) -- create a string value
+    @sa @ref basic_json(const object_t&) -- create a object value
+    @sa @ref basic_json(const array_t&) -- create a array value
+    @sa @ref basic_json(const number_float_t) -- create a number
+    (floating-point) value
+    @sa @ref basic_json(const number_integer_t) -- create a number (integer)
+    value
+    @sa @ref basic_json(const number_unsigned_t) -- create a number (unsigned)
+    value
+
+    @since version 1.0.0
+    */
+    basic_json(const value_t value_type)
+        : m_type(value_type), m_value(value_type)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a null object (implicitly)
+
+    Create a `null` JSON value. This is the implicit version of the `null`
+    value constructor as it takes no parameters.
+
+    @note The class invariant is satisfied, because it poses no requirements
+    for null values.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this constructor never throws
+    exceptions.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - As postcondition, it holds: `basic_json().empty() == true`.
+
+    @liveexample{The following code shows the constructor for a `null` JSON
+    value.,basic_json}
+
+    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
+
+    @since version 1.0.0
+    */
+    basic_json() = default;
+
+    /*!
+    @brief create a null object (explicitly)
+
+    Create a `null` JSON value. This is the explicitly version of the `null`
+    value constructor as it takes a null pointer as parameter. It allows to
+    create `null` values by explicitly assigning a `nullptr` to a JSON value.
+    The passed null pointer itself is not read -- it is only used to choose
+    the right constructor.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this constructor never throws
+    exceptions.
+
+    @liveexample{The following code shows the constructor with null pointer
+    parameter.,basic_json__nullptr_t}
+
+    @sa @ref basic_json() -- default constructor (implicitly creating a `null`
+    value)
+
+    @since version 1.0.0
+    */
+    basic_json(std::nullptr_t) noexcept
+        : basic_json(value_t::null)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an object (explicit)
+
+    Create an object JSON value with a given content.
+
+    @param[in] val  a value for the object
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for object value fails
+
+    @liveexample{The following code shows the constructor with an @ref
+    object_t parameter.,basic_json__object_t}
+
+    @sa @ref basic_json(const CompatibleObjectType&) -- create an object value
+    from a compatible STL container
+
+    @since version 1.0.0
+    */
+    basic_json(const object_t& val)
+        : m_type(value_t::object), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an object (implicit)
+
+    Create an object JSON value with a given content. This constructor allows
+    any type @a CompatibleObjectType that can be used to construct values of
+    type @ref object_t.
+
+    @tparam CompatibleObjectType An object type whose `key_type` and
+    `value_type` is compatible to @ref object_t. Examples include `std::map`,
+    `std::unordered_map`, `std::multimap`, and `std::unordered_multimap` with
+    a `key_type` of `std::string`, and a `value_type` from which a @ref
+    basic_json value can be constructed.
+
+    @param[in] val  a value for the object
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for object value fails
+
+    @liveexample{The following code shows the constructor with several
+    compatible object type parameters.,basic_json__CompatibleObjectType}
+
+    @sa @ref basic_json(const object_t&) -- create an object value
+
+    @since version 1.0.0
+    */
+    template <class CompatibleObjectType, typename
+              std::enable_if<
+                  std::is_constructible<typename object_t::key_type, typename CompatibleObjectType::key_type>::value and
+                  std::is_constructible<basic_json, typename CompatibleObjectType::mapped_type>::value, int>::type
+              = 0>
+    basic_json(const CompatibleObjectType& val)
+        : m_type(value_t::object)
+    {
+        using std::begin;
+        using std::end;
+        m_value.object = create<object_t>(begin(val), end(val));
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an array (explicit)
+
+    Create an array JSON value with a given content.
+
+    @param[in] val  a value for the array
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for array value fails
+
+    @liveexample{The following code shows the constructor with an @ref array_t
+    parameter.,basic_json__array_t}
+
+    @sa @ref basic_json(const CompatibleArrayType&) -- create an array value
+    from a compatible STL containers
+
+    @since version 1.0.0
+    */
+    basic_json(const array_t& val)
+        : m_type(value_t::array), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an array (implicit)
+
+    Create an array JSON value with a given content. This constructor allows
+    any type @a CompatibleArrayType that can be used to construct values of
+    type @ref array_t.
+
+    @tparam CompatibleArrayType An object type whose `value_type` is
+    compatible to @ref array_t. Examples include `std::vector`, `std::deque`,
+    `std::list`, `std::forward_list`, `std::array`, `std::set`,
+    `std::unordered_set`, `std::multiset`, and `unordered_multiset` with a
+    `value_type` from which a @ref basic_json value can be constructed.
+
+    @param[in] val  a value for the array
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for array value fails
+
+    @liveexample{The following code shows the constructor with several
+    compatible array type parameters.,basic_json__CompatibleArrayType}
+
+    @sa @ref basic_json(const array_t&) -- create an array value
+
+    @since version 1.0.0
+    */
+    template <class CompatibleArrayType, typename
+              std::enable_if<
+                  not std::is_same<CompatibleArrayType, typename basic_json_t::iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename basic_json_t::reverse_iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_reverse_iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename array_t::iterator>::value and
+                  not std::is_same<CompatibleArrayType, typename array_t::const_iterator>::value and
+                  std::is_constructible<basic_json, typename CompatibleArrayType::value_type>::value, int>::type
+              = 0>
+    basic_json(const CompatibleArrayType& val)
+        : m_type(value_t::array)
+    {
+        using std::begin;
+        using std::end;
+        m_value.array = create<array_t>(begin(val), end(val));
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a string (explicit)
+
+    Create an string JSON value with a given content.
+
+    @param[in] val  a value for the string
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for string value fails
+
+    @liveexample{The following code shows the constructor with an @ref
+    string_t parameter.,basic_json__string_t}
+
+    @sa @ref basic_json(const typename string_t::value_type*) -- create a
+    string value from a character pointer
+    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
+    from a compatible string container
+
+    @since version 1.0.0
+    */
+    basic_json(const string_t& val)
+        : m_type(value_t::string), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a string (explicit)
+
+    Create a string JSON value with a given content.
+
+    @param[in] val  a literal value for the string
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for string value fails
+
+    @liveexample{The following code shows the constructor with string literal
+    parameter.,basic_json__string_t_value_type}
+
+    @sa @ref basic_json(const string_t&) -- create a string value
+    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
+    from a compatible string container
+
+    @since version 1.0.0
+    */
+    basic_json(const typename string_t::value_type* val)
+        : basic_json(string_t(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a string (implicit)
+
+    Create a string JSON value with a given content.
+
+    @param[in] val  a value for the string
+
+    @tparam CompatibleStringType an string type which is compatible to @ref
+    string_t, for instance `std::string`.
+
+    @complexity Linear in the size of the passed @a val.
+
+    @throw std::bad_alloc if allocation for string value fails
+
+    @liveexample{The following code shows the construction of a string value
+    from a compatible type.,basic_json__CompatibleStringType}
+
+    @sa @ref basic_json(const string_t&) -- create a string value
+    @sa @ref basic_json(const typename string_t::value_type*) -- create a
+    string value from a character pointer
+
+    @since version 1.0.0
+    */
+    template <class CompatibleStringType, typename
+              std::enable_if<
+                  std::is_constructible<string_t, CompatibleStringType>::value, int>::type
+              = 0>
+    basic_json(const CompatibleStringType& val)
+        : basic_json(string_t(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a boolean (explicit)
+
+    Creates a JSON boolean type from a given value.
+
+    @param[in] val  a boolean value to store
+
+    @complexity Constant.
+
+    @liveexample{The example below demonstrates boolean
+    values.,basic_json__boolean_t}
+
+    @since version 1.0.0
+    */
+    basic_json(boolean_t val) noexcept
+        : m_type(value_t::boolean), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an integer number (explicit)
+
+    Create an integer number JSON value with a given content.
+
+    @tparam T A helper type to remove this function via SFINAE in case @ref
+    number_integer_t is the same as `int`. In this case, this constructor
+    would have the same signature as @ref basic_json(const int value). Note
+    the helper type @a T is not visible in this constructor's interface.
+
+    @param[in] val  an integer to create a JSON number from
+
+    @complexity Constant.
+
+    @liveexample{The example below shows the construction of an integer
+    number value.,basic_json__number_integer_t}
+
+    @sa @ref basic_json(const int) -- create a number value (integer)
+    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
+    value (integer) from a compatible number type
+
+    @since version 1.0.0
+    */
+    template<typename T,
+             typename std::enable_if<
+                 not (std::is_same<T, int>::value)
+                 and std::is_same<T, number_integer_t>::value
+                 , int>::type
+             = 0>
+    basic_json(const number_integer_t val) noexcept
+        : m_type(value_t::number_integer), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an integer number from an enum type (explicit)
+
+    Create an integer number JSON value with a given content.
+
+    @param[in] val  an integer to create a JSON number from
+
+    @note This constructor allows to pass enums directly to a constructor. As
+    C++ has no way of specifying the type of an anonymous enum explicitly, we
+    can only rely on the fact that such values implicitly convert to int. As
+    int may already be the same type of number_integer_t, we may need to
+    switch off the constructor @ref basic_json(const number_integer_t).
+
+    @complexity Constant.
+
+    @liveexample{The example below shows the construction of an integer
+    number value from an anonymous enum.,basic_json__const_int}
+
+    @sa @ref basic_json(const number_integer_t) -- create a number value
+    (integer)
+    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
+    value (integer) from a compatible number type
+
+    @since version 1.0.0
+    */
+    basic_json(const int val) noexcept
+        : m_type(value_t::number_integer),
+          m_value(static_cast<number_integer_t>(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an integer number (implicit)
+
+    Create an integer number JSON value with a given content. This constructor
+    allows any type @a CompatibleNumberIntegerType that can be used to
+    construct values of type @ref number_integer_t.
+
+    @tparam CompatibleNumberIntegerType An integer type which is compatible to
+    @ref number_integer_t. Examples include the types `int`, `int32_t`,
+    `long`, and `short`.
+
+    @param[in] val  an integer to create a JSON number from
+
+    @complexity Constant.
+
+    @liveexample{The example below shows the construction of several integer
+    number values from compatible
+    types.,basic_json__CompatibleIntegerNumberType}
+
+    @sa @ref basic_json(const number_integer_t) -- create a number value
+    (integer)
+    @sa @ref basic_json(const int) -- create a number value (integer)
+
+    @since version 1.0.0
+    */
+    template<typename CompatibleNumberIntegerType, typename
+             std::enable_if<
+                 std::is_constructible<number_integer_t, CompatibleNumberIntegerType>::value and
+                 std::numeric_limits<CompatibleNumberIntegerType>::is_integer and
+                 std::numeric_limits<CompatibleNumberIntegerType>::is_signed,
+                 CompatibleNumberIntegerType>::type
+             = 0>
+    basic_json(const CompatibleNumberIntegerType val) noexcept
+        : m_type(value_t::number_integer),
+          m_value(static_cast<number_integer_t>(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an unsigned integer number (explicit)
+
+    Create an unsigned integer number JSON value with a given content.
+
+    @tparam T  helper type to compare number_unsigned_t and unsigned int (not
+    visible in) the interface.
+
+    @param[in] val  an integer to create a JSON number from
+
+    @complexity Constant.
+
+    @sa @ref basic_json(const CompatibleNumberUnsignedType) -- create a number
+    value (unsigned integer) from a compatible number type
+
+    @since version 2.0.0
+    */
+    template<typename T,
+             typename std::enable_if<
+                 not (std::is_same<T, int>::value)
+                 and std::is_same<T, number_unsigned_t>::value
+                 , int>::type
+             = 0>
+    basic_json(const number_unsigned_t val) noexcept
+        : m_type(value_t::number_unsigned), m_value(val)
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an unsigned number (implicit)
+
+    Create an unsigned number JSON value with a given content. This
+    constructor allows any type @a CompatibleNumberUnsignedType that can be
+    used to construct values of type @ref number_unsigned_t.
+
+    @tparam CompatibleNumberUnsignedType An integer type which is compatible
+    to @ref number_unsigned_t. Examples may include the types `unsigned int`,
+    `uint32_t`, or `unsigned short`.
+
+    @param[in] val  an unsigned integer to create a JSON number from
+
+    @complexity Constant.
+
+    @sa @ref basic_json(const number_unsigned_t) -- create a number value
+    (unsigned)
+
+    @since version 2.0.0
+    */
+    template <typename CompatibleNumberUnsignedType, typename
+              std::enable_if <
+                  std::is_constructible<number_unsigned_t, CompatibleNumberUnsignedType>::value and
+                  std::numeric_limits<CompatibleNumberUnsignedType>::is_integer and
+                  not std::numeric_limits<CompatibleNumberUnsignedType>::is_signed,
+                  CompatibleNumberUnsignedType>::type
+              = 0>
+    basic_json(const CompatibleNumberUnsignedType val) noexcept
+        : m_type(value_t::number_unsigned),
+          m_value(static_cast<number_unsigned_t>(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a floating-point number (explicit)
+
+    Create a floating-point number JSON value with a given content.
+
+    @param[in] val  a floating-point value to create a JSON number from
+
+    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
+    disallows NaN values:
+    > Numeric values that cannot be represented in the grammar below (such as
+    > Infinity and NaN) are not permitted.
+    In case the parameter @a val is not a number, a JSON null value is created
+    instead.
+
+    @complexity Constant.
+
+    @liveexample{The following example creates several floating-point
+    values.,basic_json__number_float_t}
+
+    @sa @ref basic_json(const CompatibleNumberFloatType) -- create a number
+    value (floating-point) from a compatible number type
+
+    @since version 1.0.0
+    */
+    basic_json(const number_float_t val) noexcept
+        : m_type(value_t::number_float), m_value(val)
+    {
+        // replace infinity and NAN by null
+        if (not std::isfinite(val))
+        {
+            m_type = value_t::null;
+            m_value = json_value();
+        }
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief create an floating-point number (implicit)
+
+    Create an floating-point number JSON value with a given content. This
+    constructor allows any type @a CompatibleNumberFloatType that can be used
+    to construct values of type @ref number_float_t.
+
+    @tparam CompatibleNumberFloatType A floating-point type which is
+    compatible to @ref number_float_t. Examples may include the types `float`
+    or `double`.
+
+    @param[in] val  a floating-point to create a JSON number from
+
+    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
+    disallows NaN values:
+    > Numeric values that cannot be represented in the grammar below (such as
+    > Infinity and NaN) are not permitted.
+    In case the parameter @a val is not a number, a JSON null value is
+    created instead.
+
+    @complexity Constant.
+
+    @liveexample{The example below shows the construction of several
+    floating-point number values from compatible
+    types.,basic_json__CompatibleNumberFloatType}
+
+    @sa @ref basic_json(const number_float_t) -- create a number value
+    (floating-point)
+
+    @since version 1.0.0
+    */
+    template<typename CompatibleNumberFloatType, typename = typename
+             std::enable_if<
+                 std::is_constructible<number_float_t, CompatibleNumberFloatType>::value and
+                 std::is_floating_point<CompatibleNumberFloatType>::value>::type
+             >
+    basic_json(const CompatibleNumberFloatType val) noexcept
+        : basic_json(number_float_t(val))
+    {
+        assert_invariant();
+    }
+
+    /*!
+    @brief create a container (array or object) from an initializer list
+
+    Creates a JSON value of type array or object from the passed initializer
+    list @a init. In case @a type_deduction is `true` (default), the type of
+    the JSON value to be created is deducted from the initializer list @a init
+    according to the following rules:
+
+    1. If the list is empty, an empty JSON object value `{}` is created.
+    2. If the list consists of pairs whose first element is a string, a JSON
+       object value is created where the first elements of the pairs are
+       treated as keys and the second elements are as values.
+    3. In all other cases, an array is created.
+
+    The rules aim to create the best fit between a C++ initializer list and
+    JSON values. The rationale is as follows:
+
+    1. The empty initializer list is written as `{}` which is exactly an empty
+       JSON object.
+    2. C++ has now way of describing mapped types other than to list a list of
+       pairs. As JSON requires that keys must be of type string, rule 2 is the
+       weakest constraint one can pose on initializer lists to interpret them
+       as an object.
+    3. In all other cases, the initializer list could not be interpreted as
+       JSON object type, so interpreting it as JSON array type is safe.
+
+    With the rules described above, the following JSON values cannot be
+    expressed by an initializer list:
+
+    - the empty array (`[]`): use @ref array(std::initializer_list<basic_json>)
+      with an empty initializer list in this case
+    - arrays whose elements satisfy rule 2: use @ref
+      array(std::initializer_list<basic_json>) with the same initializer list
+      in this case
+
+    @note When used without parentheses around an empty initializer list, @ref
+    basic_json() is called instead of this function, yielding the JSON null
+    value.
+
+    @param[in] init  initializer list with JSON values
+
+    @param[in] type_deduction internal parameter; when set to `true`, the type
+    of the JSON value is deducted from the initializer list @a init; when set
+    to `false`, the type provided via @a manual_type is forced. This mode is
+    used by the functions @ref array(std::initializer_list<basic_json>) and
+    @ref object(std::initializer_list<basic_json>).
+
+    @param[in] manual_type internal parameter; when @a type_deduction is set
+    to `false`, the created JSON value will use the provided type (only @ref
+    value_t::array and @ref value_t::object are valid); when @a type_deduction
+    is set to `true`, this parameter has no effect
+
+    @throw std::domain_error if @a type_deduction is `false`, @a manual_type
+    is `value_t::object`, but @a init contains an element which is not a pair
+    whose first element is a string; example: `"cannot create object from
+    initializer list"`
+
+    @complexity Linear in the size of the initializer list @a init.
+
+    @liveexample{The example below shows how JSON values are created from
+    initializer lists.,basic_json__list_init_t}
+
+    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
+    value from an initializer list
+    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
+    value from an initializer list
+
+    @since version 1.0.0
+    */
+    basic_json(std::initializer_list<basic_json> init,
+               bool type_deduction = true,
+               value_t manual_type = value_t::array)
+    {
+        // check if each element is an array with two elements whose first
+        // element is a string
+        bool is_an_object = std::all_of(init.begin(), init.end(),
+                                        [](const basic_json & element)
+        {
+            return element.is_array() and element.size() == 2 and element[0].is_string();
+        });
+
+        // adjust type if type deduction is not wanted
+        if (not type_deduction)
+        {
+            // if array is wanted, do not create an object though possible
+            if (manual_type == value_t::array)
+            {
+                is_an_object = false;
+            }
+
+            // if object is wanted but impossible, throw an exception
+            if (manual_type == value_t::object and not is_an_object)
+            {
+                throw std::domain_error("cannot create object from initializer list");
+            }
+        }
+
+        if (is_an_object)
+        {
+            // the initializer list is a list of pairs -> create object
+            m_type = value_t::object;
+            m_value = value_t::object;
+
+            std::for_each(init.begin(), init.end(), [this](const basic_json & element)
+            {
+                m_value.object->emplace(*(element[0].m_value.string), element[1]);
+            });
+        }
+        else
+        {
+            // the initializer list describes an array -> create array
+            m_type = value_t::array;
+            m_value.array = create<array_t>(init);
+        }
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief explicitly create an array from an initializer list
+
+    Creates a JSON array value from a given initializer list. That is, given a
+    list of values `a, b, c`, creates the JSON value `[a, b, c]`. If the
+    initializer list is empty, the empty array `[]` is created.
+
+    @note This function is only needed to express two edge cases that cannot
+    be realized with the initializer list constructor (@ref
+    basic_json(std::initializer_list<basic_json>, bool, value_t)). These cases
+    are:
+    1. creating an array whose elements are all pairs whose first element is a
+    string -- in this case, the initializer list constructor would create an
+    object, taking the first elements as keys
+    2. creating an empty array -- passing the empty initializer list to the
+    initializer list constructor yields an empty object
+
+    @param[in] init  initializer list with JSON values to create an array from
+    (optional)
+
+    @return JSON array value
+
+    @complexity Linear in the size of @a init.
+
+    @liveexample{The following code shows an example for the `array`
+    function.,array}
+
+    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
+    create a JSON value from an initializer list
+    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
+    value from an initializer list
+
+    @since version 1.0.0
+    */
+    static basic_json array(std::initializer_list<basic_json> init =
+                                std::initializer_list<basic_json>())
+    {
+        return basic_json(init, false, value_t::array);
+    }
+
+    /*!
+    @brief explicitly create an object from an initializer list
+
+    Creates a JSON object value from a given initializer list. The initializer
+    lists elements must be pairs, and their first elements must be strings. If
+    the initializer list is empty, the empty object `{}` is created.
+
+    @note This function is only added for symmetry reasons. In contrast to the
+    related function @ref array(std::initializer_list<basic_json>), there are
+    no cases which can only be expressed by this function. That is, any
+    initializer list @a init can also be passed to the initializer list
+    constructor @ref basic_json(std::initializer_list<basic_json>, bool,
+    value_t).
+
+    @param[in] init  initializer list to create an object from (optional)
+
+    @return JSON object value
+
+    @throw std::domain_error if @a init is not a pair whose first elements are
+    strings; thrown by
+    @ref basic_json(std::initializer_list<basic_json>, bool, value_t)
+
+    @complexity Linear in the size of @a init.
+
+    @liveexample{The following code shows an example for the `object`
+    function.,object}
+
+    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
+    create a JSON value from an initializer list
+    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
+    value from an initializer list
+
+    @since version 1.0.0
+    */
+    static basic_json object(std::initializer_list<basic_json> init =
+                                 std::initializer_list<basic_json>())
+    {
+        return basic_json(init, false, value_t::object);
+    }
+
+    /*!
+    @brief construct an array with count copies of given value
+
+    Constructs a JSON array value by creating @a cnt copies of a passed value.
+    In case @a cnt is `0`, an empty array is created. As postcondition,
+    `std::distance(begin(),end()) == cnt` holds.
+
+    @param[in] cnt  the number of JSON copies of @a val to create
+    @param[in] val  the JSON value to copy
+
+    @complexity Linear in @a cnt.
+
+    @liveexample{The following code shows examples for the @ref
+    basic_json(size_type\, const basic_json&)
+    constructor.,basic_json__size_type_basic_json}
+
+    @since version 1.0.0
+    */
+    basic_json(size_type cnt, const basic_json& val)
+        : m_type(value_t::array)
+    {
+        m_value.array = create<array_t>(cnt, val);
+        assert_invariant();
+    }
+
+    /*!
+    @brief construct a JSON container given an iterator range
+
+    Constructs the JSON value with the contents of the range `[first, last)`.
+    The semantics depends on the different types a JSON value can have:
+    - In case of primitive types (number, boolean, or string), @a first must
+      be `begin()` and @a last must be `end()`. In this case, the value is
+      copied. Otherwise, std::out_of_range is thrown.
+    - In case of structured types (array, object), the constructor behaves as
+      similar versions for `std::vector`.
+    - In case of a null type, std::domain_error is thrown.
+
+    @tparam InputIT an input iterator type (@ref iterator or @ref
+    const_iterator)
+
+    @param[in] first begin of the range to copy from (included)
+    @param[in] last end of the range to copy from (excluded)
+
+    @pre Iterators @a first and @a last must be initialized.
+
+    @throw std::domain_error if iterators are not compatible; that is, do not
+    belong to the same JSON value; example: `"iterators are not compatible"`
+    @throw std::out_of_range if iterators are for a primitive type (number,
+    boolean, or string) where an out of range error can be detected easily;
+    example: `"iterators out of range"`
+    @throw std::bad_alloc if allocation for object, array, or string fails
+    @throw std::domain_error if called with a null value; example: `"cannot
+    use construct with iterators from null"`
+
+    @complexity Linear in distance between @a first and @a last.
+
+    @liveexample{The example below shows several ways to create JSON values by
+    specifying a subrange with iterators.,basic_json__InputIt_InputIt}
+
+    @since version 1.0.0
+    */
+    template <class InputIT, typename
+              std::enable_if<
+                  std::is_same<InputIT, typename basic_json_t::iterator>::value or
+                  std::is_same<InputIT, typename basic_json_t::const_iterator>::value
+                  , int>::type
+              = 0>
+    basic_json(InputIT first, InputIT last)
+    {
+        assert(first.m_object != nullptr);
+        assert(last.m_object != nullptr);
+
+        // make sure iterator fits the current value
+        if (first.m_object != last.m_object)
+        {
+            throw std::domain_error("iterators are not compatible");
+        }
+
+        // copy type from first iterator
+        m_type = first.m_object->m_type;
+
+        // check if iterator range is complete for primitive values
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
+            {
+                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
+                {
+                    throw std::out_of_range("iterators out of range");
+                }
+                break;
+            }
+
+            default:
+            {
+                break;
+            }
+        }
+
+        switch (m_type)
+        {
+            case value_t::number_integer:
+            {
+                m_value.number_integer = first.m_object->m_value.number_integer;
+                break;
+            }
+
+            case value_t::number_unsigned:
+            {
+                m_value.number_unsigned = first.m_object->m_value.number_unsigned;
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                m_value.number_float = first.m_object->m_value.number_float;
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                m_value.boolean = first.m_object->m_value.boolean;
+                break;
+            }
+
+            case value_t::string:
+            {
+                m_value = *first.m_object->m_value.string;
+                break;
+            }
+
+            case value_t::object:
+            {
+                m_value.object = create<object_t>(first.m_it.object_iterator, last.m_it.object_iterator);
+                break;
+            }
+
+            case value_t::array:
+            {
+                m_value.array = create<array_t>(first.m_it.array_iterator, last.m_it.array_iterator);
+                break;
+            }
+
+            default:
+            {
+                throw std::domain_error("cannot use construct with iterators from " + first.m_object->type_name());
+            }
+        }
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief construct a JSON value given an input stream
+
+    @param[in,out] i  stream to read a serialized JSON value from
+    @param[in] cb a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates constructing a JSON value from
+    a `std::stringstream` with and without callback
+    function.,basic_json__istream}
+
+    @since version 2.0.0
+    */
+    explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)
+    {
+        *this = parser(i, cb).parse();
+        assert_invariant();
+    }
+
+    ///////////////////////////////////////
+    // other constructors and destructor //
+    ///////////////////////////////////////
+
+    /*!
+    @brief copy constructor
+
+    Creates a copy of a given JSON value.
+
+    @param[in] other  the JSON value to copy
+
+    @complexity Linear in the size of @a other.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
+    - As postcondition, it holds: `other == basic_json(other)`.
+
+    @throw std::bad_alloc if allocation for object, array, or string fails.
+
+    @liveexample{The following code shows an example for the copy
+    constructor.,basic_json__basic_json}
+
+    @since version 1.0.0
+    */
+    basic_json(const basic_json& other)
+        : m_type(other.m_type)
+    {
+        // check of passed value is valid
+        other.assert_invariant();
+
+        switch (m_type)
+        {
+            case value_t::object:
+            {
+                m_value = *other.m_value.object;
+                break;
+            }
+
+            case value_t::array:
+            {
+                m_value = *other.m_value.array;
+                break;
+            }
+
+            case value_t::string:
+            {
+                m_value = *other.m_value.string;
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                m_value = other.m_value.boolean;
+                break;
+            }
+
+            case value_t::number_integer:
+            {
+                m_value = other.m_value.number_integer;
+                break;
+            }
+
+            case value_t::number_unsigned:
+            {
+                m_value = other.m_value.number_unsigned;
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                m_value = other.m_value.number_float;
+                break;
+            }
+
+            default:
+            {
+                break;
+            }
+        }
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief move constructor
+
+    Move constructor. Constructs a JSON value with the contents of the given
+    value @a other using move semantics. It "steals" the resources from @a
+    other and leaves it as JSON null value.
+
+    @param[in,out] other  value to move to this object
+
+    @post @a other is a JSON null value
+
+    @complexity Constant.
+
+    @liveexample{The code below shows the move constructor explicitly called
+    via std::move.,basic_json__moveconstructor}
+
+    @since version 1.0.0
+    */
+    basic_json(basic_json&& other) noexcept
+        : m_type(std::move(other.m_type)),
+          m_value(std::move(other.m_value))
+    {
+        // check that passed value is valid
+        other.assert_invariant();
+
+        // invalidate payload
+        other.m_type = value_t::null;
+        other.m_value = {};
+
+        assert_invariant();
+    }
+
+    /*!
+    @brief copy assignment
+
+    Copy assignment operator. Copies a JSON value via the "copy and swap"
+    strategy: It is expressed in terms of the copy constructor, destructor,
+    and the swap() member function.
+
+    @param[in] other  value to copy from
+
+    @complexity Linear.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
+
+    @liveexample{The code below shows and example for the copy assignment. It
+    creates a copy of value `a` which is then swapped with `b`. Finally\, the
+    copy of `a` (which is the null value after the swap) is
+    destroyed.,basic_json__copyassignment}
+
+    @since version 1.0.0
+    */
+    reference& operator=(basic_json other) noexcept (
+        std::is_nothrow_move_constructible<value_t>::value and
+        std::is_nothrow_move_assignable<value_t>::value and
+        std::is_nothrow_move_constructible<json_value>::value and
+        std::is_nothrow_move_assignable<json_value>::value
+    )
+    {
+        // check that passed value is valid
+        other.assert_invariant();
+
+        using std::swap;
+        swap(m_type, other.m_type);
+        swap(m_value, other.m_value);
+
+        assert_invariant();
+        return *this;
+    }
+
+    /*!
+    @brief destructor
+
+    Destroys the JSON value and frees all allocated memory.
+
+    @complexity Linear.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
+    - All stored elements are destroyed and all memory is freed.
+
+    @since version 1.0.0
+    */
+    ~basic_json()
+    {
+        assert_invariant();
+
+        switch (m_type)
+        {
+            case value_t::object:
+            {
+                AllocatorType<object_t> alloc;
+                alloc.destroy(m_value.object);
+                alloc.deallocate(m_value.object, 1);
+                break;
+            }
+
+            case value_t::array:
+            {
+                AllocatorType<array_t> alloc;
+                alloc.destroy(m_value.array);
+                alloc.deallocate(m_value.array, 1);
+                break;
+            }
+
+            case value_t::string:
+            {
+                AllocatorType<string_t> alloc;
+                alloc.destroy(m_value.string);
+                alloc.deallocate(m_value.string, 1);
+                break;
+            }
+
+            default:
+            {
+                // all other types need no specific destructor
+                break;
+            }
+        }
+    }
+
+    /// @}
+
+  public:
+    ///////////////////////
+    // object inspection //
+    ///////////////////////
+
+    /// @name object inspection
+    /// Functions to inspect the type of a JSON value.
+    /// @{
+
+    /*!
+    @brief serialization
+
+    Serialization function for JSON values. The function tries to mimic
+    Python's `json.dumps()` function, and currently supports its @a indent
+    parameter.
+
+    @param[in] indent If indent is nonnegative, then array elements and object
+    members will be pretty-printed with that indent level. An indent level of
+    `0` will only insert newlines. `-1` (the default) selects the most compact
+    representation.
+
+    @return string containing the serialization of the JSON value
+
+    @complexity Linear.
+
+    @liveexample{The following example shows the effect of different @a indent
+    parameters to the result of the serialization.,dump}
+
+    @see https://docs.python.org/2/library/json.html#json.dump
+
+    @since version 1.0.0
+    */
+    string_t dump(const int indent = -1) const
+    {
+        std::stringstream ss;
+        // fix locale problems
+        ss.imbue(std::locale(std::locale(), new DecimalSeparator));
+
+        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
+        // string->float->string, string->double->string or string->long
+        // double->string; to be safe, we read this value from
+        // std::numeric_limits<number_float_t>::digits10
+        ss.precision(std::numeric_limits<double>::digits10);
+
+        if (indent >= 0)
+        {
+            dump(ss, true, static_cast<unsigned int>(indent));
+        }
+        else
+        {
+            dump(ss, false, 0);
+        }
+
+        return ss.str();
+    }
+
+    /*!
+    @brief return the type of the JSON value (explicit)
+
+    Return the type of the JSON value as a value from the @ref value_t
+    enumeration.
+
+    @return the type of the JSON value
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `type()` for all JSON
+    types.,type}
+
+    @since version 1.0.0
+    */
+    constexpr value_t type() const noexcept
+    {
+        return m_type;
+    }
+
+    /*!
+    @brief return whether type is primitive
+
+    This function returns true iff the JSON type is primitive (string, number,
+    boolean, or null).
+
+    @return `true` if type is primitive (string, number, boolean, or null),
+    `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_primitive()` for all JSON
+    types.,is_primitive}
+
+    @sa @ref is_structured() -- returns whether JSON value is structured
+    @sa @ref is_null() -- returns whether JSON value is `null`
+    @sa @ref is_string() -- returns whether JSON value is a string
+    @sa @ref is_boolean() -- returns whether JSON value is a boolean
+    @sa @ref is_number() -- returns whether JSON value is a number
+
+    @since version 1.0.0
+    */
+    constexpr bool is_primitive() const noexcept
+    {
+        return is_null() or is_string() or is_boolean() or is_number();
+    }
+
+    /*!
+    @brief return whether type is structured
+
+    This function returns true iff the JSON type is structured (array or
+    object).
+
+    @return `true` if type is structured (array or object), `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_structured()` for all JSON
+    types.,is_structured}
+
+    @sa @ref is_primitive() -- returns whether value is primitive
+    @sa @ref is_array() -- returns whether value is an array
+    @sa @ref is_object() -- returns whether value is an object
+
+    @since version 1.0.0
+    */
+    constexpr bool is_structured() const noexcept
+    {
+        return is_array() or is_object();
+    }
+
+    /*!
+    @brief return whether value is null
+
+    This function returns true iff the JSON value is null.
+
+    @return `true` if type is null, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_null()` for all JSON
+    types.,is_null}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_null() const noexcept
+    {
+        return m_type == value_t::null;
+    }
+
+    /*!
+    @brief return whether value is a boolean
+
+    This function returns true iff the JSON value is a boolean.
+
+    @return `true` if type is boolean, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_boolean()` for all JSON
+    types.,is_boolean}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_boolean() const noexcept
+    {
+        return m_type == value_t::boolean;
+    }
+
+    /*!
+    @brief return whether value is a number
+
+    This function returns true iff the JSON value is a number. This includes
+    both integer and floating-point values.
+
+    @return `true` if type is number (regardless whether integer, unsigned
+    integer or floating-type), `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_number()` for all JSON
+    types.,is_number}
+
+    @sa @ref is_number_integer() -- check if value is an integer or unsigned
+    integer number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
+    @sa @ref is_number_float() -- check if value is a floating-point number
+
+    @since version 1.0.0
+    */
+    constexpr bool is_number() const noexcept
+    {
+        return is_number_integer() or is_number_float();
+    }
+
+    /*!
+    @brief return whether value is an integer number
+
+    This function returns true iff the JSON value is an integer or unsigned
+    integer number. This excludes floating-point values.
+
+    @return `true` if type is an integer or unsigned integer number, `false`
+    otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_number_integer()` for all
+    JSON types.,is_number_integer}
+
+    @sa @ref is_number() -- check if value is a number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
+    @sa @ref is_number_float() -- check if value is a floating-point number
+
+    @since version 1.0.0
+    */
+    constexpr bool is_number_integer() const noexcept
+    {
+        return m_type == value_t::number_integer or m_type == value_t::number_unsigned;
+    }
+
+    /*!
+    @brief return whether value is an unsigned integer number
+
+    This function returns true iff the JSON value is an unsigned integer
+    number. This excludes floating-point and (signed) integer values.
+
+    @return `true` if type is an unsigned integer number, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_number_unsigned()` for all
+    JSON types.,is_number_unsigned}
+
+    @sa @ref is_number() -- check if value is a number
+    @sa @ref is_number_integer() -- check if value is an integer or unsigned
+    integer number
+    @sa @ref is_number_float() -- check if value is a floating-point number
+
+    @since version 2.0.0
+    */
+    constexpr bool is_number_unsigned() const noexcept
+    {
+        return m_type == value_t::number_unsigned;
+    }
+
+    /*!
+    @brief return whether value is a floating-point number
+
+    This function returns true iff the JSON value is a floating-point number.
+    This excludes integer and unsigned integer values.
+
+    @return `true` if type is a floating-point number, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_number_float()` for all
+    JSON types.,is_number_float}
+
+    @sa @ref is_number() -- check if value is number
+    @sa @ref is_number_integer() -- check if value is an integer number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
+
+    @since version 1.0.0
+    */
+    constexpr bool is_number_float() const noexcept
+    {
+        return m_type == value_t::number_float;
+    }
+
+    /*!
+    @brief return whether value is an object
+
+    This function returns true iff the JSON value is an object.
+
+    @return `true` if type is object, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_object()` for all JSON
+    types.,is_object}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_object() const noexcept
+    {
+        return m_type == value_t::object;
+    }
+
+    /*!
+    @brief return whether value is an array
+
+    This function returns true iff the JSON value is an array.
+
+    @return `true` if type is array, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_array()` for all JSON
+    types.,is_array}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_array() const noexcept
+    {
+        return m_type == value_t::array;
+    }
+
+    /*!
+    @brief return whether value is a string
+
+    This function returns true iff the JSON value is a string.
+
+    @return `true` if type is string, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_string()` for all JSON
+    types.,is_string}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_string() const noexcept
+    {
+        return m_type == value_t::string;
+    }
+
+    /*!
+    @brief return whether value is discarded
+
+    This function returns true iff the JSON value was discarded during parsing
+    with a callback function (see @ref parser_callback_t).
+
+    @note This function will always be `false` for JSON values after parsing.
+    That is, discarded values can only occur during parsing, but will be
+    removed when inside a structured value or replaced by null in other cases.
+
+    @return `true` if type is discarded, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_discarded()` for all JSON
+    types.,is_discarded}
+
+    @since version 1.0.0
+    */
+    constexpr bool is_discarded() const noexcept
+    {
+        return m_type == value_t::discarded;
+    }
+
+    /*!
+    @brief return the type of the JSON value (implicit)
+
+    Implicitly return the type of the JSON value as a value from the @ref
+    value_t enumeration.
+
+    @return the type of the JSON value
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies the @ref value_t operator for
+    all JSON types.,operator__value_t}
+
+    @since version 1.0.0
+    */
+    constexpr operator value_t() const noexcept
+    {
+        return m_type;
+    }
+
+    /// @}
+
+  private:
+    //////////////////
+    // value access //
+    //////////////////
+
+    /// get an object (explicit)
+    template <class T, typename
+              std::enable_if<
+                  std::is_convertible<typename object_t::key_type, typename T::key_type>::value and
+                  std::is_convertible<basic_json_t, typename T::mapped_type>::value
+                  , int>::type = 0>
+    T get_impl(T*) const
+    {
+        if (is_object())
+        {
+            return T(m_value.object->begin(), m_value.object->end());
+        }
+        else
+        {
+            throw std::domain_error("type must be object, but is " + type_name());
+        }
+    }
+
+    /// get an object (explicit)
+    object_t get_impl(object_t*) const
+    {
+        if (is_object())
+        {
+            return *(m_value.object);
+        }
+        else
+        {
+            throw std::domain_error("type must be object, but is " + type_name());
+        }
+    }
+
+    /// get an array (explicit)
+    template <class T, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, typename T::value_type>::value and
+                  not std::is_same<basic_json_t, typename T::value_type>::value and
+                  not std::is_arithmetic<T>::value and
+                  not std::is_convertible<std::string, T>::value and
+                  not has_mapped_type<T>::value
+                  , int>::type = 0>
+    T get_impl(T*) const
+    {
+        if (is_array())
+        {
+            T to_vector;
+            std::transform(m_value.array->begin(), m_value.array->end(),
+                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
+            {
+                return i.get<typename T::value_type>();
+            });
+            return to_vector;
+        }
+        else
+        {
+            throw std::domain_error("type must be array, but is " + type_name());
+        }
+    }
+
+    /// get an array (explicit)
+    template <class T, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, T>::value and
+                  not std::is_same<basic_json_t, T>::value
+                  , int>::type = 0>
+    std::vector<T> get_impl(std::vector<T>*) const
+    {
+        if (is_array())
+        {
+            std::vector<T> to_vector;
+            to_vector.reserve(m_value.array->size());
+            std::transform(m_value.array->begin(), m_value.array->end(),
+                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
+            {
+                return i.get<T>();
+            });
+            return to_vector;
+        }
+        else
+        {
+            throw std::domain_error("type must be array, but is " + type_name());
+        }
+    }
+
+    /// get an array (explicit)
+    template <class T, typename
+              std::enable_if<
+                  std::is_same<basic_json, typename T::value_type>::value and
+                  not has_mapped_type<T>::value
+                  , int>::type = 0>
+    T get_impl(T*) const
+    {
+        if (is_array())
+        {
+            return T(m_value.array->begin(), m_value.array->end());
+        }
+        else
+        {
+            throw std::domain_error("type must be array, but is " + type_name());
+        }
+    }
+
+    /// get an array (explicit)
+    array_t get_impl(array_t*) const
+    {
+        if (is_array())
+        {
+            return *(m_value.array);
+        }
+        else
+        {
+            throw std::domain_error("type must be array, but is " + type_name());
+        }
+    }
+
+    /// get a string (explicit)
+    template <typename T, typename
+              std::enable_if<
+                  std::is_convertible<string_t, T>::value
+                  , int>::type = 0>
+    T get_impl(T*) const
+    {
+        if (is_string())
+        {
+            return *m_value.string;
+        }
+        else
+        {
+            throw std::domain_error("type must be string, but is " + type_name());
+        }
+    }
+
+    /// get a number (explicit)
+    template<typename T, typename
+             std::enable_if<
+                 std::is_arithmetic<T>::value
+                 , int>::type = 0>
+    T get_impl(T*) const
+    {
+        switch (m_type)
+        {
+            case value_t::number_integer:
+            {
+                return static_cast<T>(m_value.number_integer);
+            }
+
+            case value_t::number_unsigned:
+            {
+                return static_cast<T>(m_value.number_unsigned);
+            }
+
+            case value_t::number_float:
+            {
+                return static_cast<T>(m_value.number_float);
+            }
+
+            default:
+            {
+                throw std::domain_error("type must be number, but is " + type_name());
+            }
+        }
+    }
+
+    /// get a boolean (explicit)
+    constexpr boolean_t get_impl(boolean_t*) const
+    {
+        return is_boolean()
+               ? m_value.boolean
+               : throw std::domain_error("type must be boolean, but is " + type_name());
+    }
+
+    /// get a pointer to the value (object)
+    object_t* get_impl_ptr(object_t*) noexcept
+    {
+        return is_object() ? m_value.object : nullptr;
+    }
+
+    /// get a pointer to the value (object)
+    constexpr const object_t* get_impl_ptr(const object_t*) const noexcept
+    {
+        return is_object() ? m_value.object : nullptr;
+    }
+
+    /// get a pointer to the value (array)
+    array_t* get_impl_ptr(array_t*) noexcept
+    {
+        return is_array() ? m_value.array : nullptr;
+    }
+
+    /// get a pointer to the value (array)
+    constexpr const array_t* get_impl_ptr(const array_t*) const noexcept
+    {
+        return is_array() ? m_value.array : nullptr;
+    }
+
+    /// get a pointer to the value (string)
+    string_t* get_impl_ptr(string_t*) noexcept
+    {
+        return is_string() ? m_value.string : nullptr;
+    }
+
+    /// get a pointer to the value (string)
+    constexpr const string_t* get_impl_ptr(const string_t*) const noexcept
+    {
+        return is_string() ? m_value.string : nullptr;
+    }
+
+    /// get a pointer to the value (boolean)
+    boolean_t* get_impl_ptr(boolean_t*) noexcept
+    {
+        return is_boolean() ? &m_value.boolean : nullptr;
+    }
+
+    /// get a pointer to the value (boolean)
+    constexpr const boolean_t* get_impl_ptr(const boolean_t*) const noexcept
+    {
+        return is_boolean() ? &m_value.boolean : nullptr;
+    }
+
+    /// get a pointer to the value (integer number)
+    number_integer_t* get_impl_ptr(number_integer_t*) noexcept
+    {
+        return is_number_integer() ? &m_value.number_integer : nullptr;
+    }
+
+    /// get a pointer to the value (integer number)
+    constexpr const number_integer_t* get_impl_ptr(const number_integer_t*) const noexcept
+    {
+        return is_number_integer() ? &m_value.number_integer : nullptr;
+    }
+
+    /// get a pointer to the value (unsigned number)
+    number_unsigned_t* get_impl_ptr(number_unsigned_t*) noexcept
+    {
+        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
+    }
+
+    /// get a pointer to the value (unsigned number)
+    constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t*) const noexcept
+    {
+        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
+    }
+
+    /// get a pointer to the value (floating-point number)
+    number_float_t* get_impl_ptr(number_float_t*) noexcept
+    {
+        return is_number_float() ? &m_value.number_float : nullptr;
+    }
+
+    /// get a pointer to the value (floating-point number)
+    constexpr const number_float_t* get_impl_ptr(const number_float_t*) const noexcept
+    {
+        return is_number_float() ? &m_value.number_float : nullptr;
+    }
+
+    /*!
+    @brief helper function to implement get_ref()
+
+    This funcion helps to implement get_ref() without code duplication for
+    const and non-const overloads
+
+    @tparam ThisType will be deduced as `basic_json` or `const basic_json`
+
+    @throw std::domain_error if ReferenceType does not match underlying value
+    type of the current JSON
+    */
+    template<typename ReferenceType, typename ThisType>
+    static ReferenceType get_ref_impl(ThisType& obj)
+    {
+        // helper type
+        using PointerType = typename std::add_pointer<ReferenceType>::type;
+
+        // delegate the call to get_ptr<>()
+        auto ptr = obj.template get_ptr<PointerType>();
+
+        if (ptr != nullptr)
+        {
+            return *ptr;
+        }
+        else
+        {
+            throw std::domain_error("incompatible ReferenceType for get_ref, actual type is " +
+                                    obj.type_name());
+        }
+    }
+
+  public:
+
+    /// @name value access
+    /// Direct access to the stored value of a JSON value.
+    /// @{
+
+    /*!
+    @brief get a value (explicit)
+
+    Explicit type conversion between the JSON value and a compatible value.
+
+    @tparam ValueType non-pointer type compatible to the JSON value, for
+    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
+    `std::vector` types for JSON arrays
+
+    @return copy of the JSON value, converted to type @a ValueType
+
+    @throw std::domain_error in case passed type @a ValueType is incompatible
+    to JSON; example: `"type must be object, but is null"`
+
+    @complexity Linear in the size of the JSON value.
+
+    @liveexample{The example below shows several conversions from JSON values
+    to other types. There a few things to note: (1) Floating-point numbers can
+    be converted to integers\, (2) A JSON array can be converted to a standard
+    `std::vector<short>`\, (3) A JSON object can be converted to C++
+    associative containers such as `std::unordered_map<std::string\,
+    json>`.,get__ValueType_const}
+
+    @internal
+    The idea of using a casted null pointer to choose the correct
+    implementation is from <http://stackoverflow.com/a/8315197/266378>.
+    @endinternal
+
+    @sa @ref operator ValueType() const for implicit conversion
+    @sa @ref get() for pointer-member access
+
+    @since version 1.0.0
+    */
+    template<typename ValueType, typename
+             std::enable_if<
+                 not std::is_pointer<ValueType>::value
+                 , int>::type = 0>
+    ValueType get() const
+    {
+        return get_impl(static_cast<ValueType*>(nullptr));
+    }
+
+    /*!
+    @brief get a pointer value (explicit)
+
+    Explicit pointer access to the internally stored JSON value. No copies are
+    made.
+
+    @warning The pointer becomes invalid if the underlying JSON object
+    changes.
+
+    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
+    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
+    @ref number_unsigned_t, or @ref number_float_t.
+
+    @return pointer to the internally stored JSON value if the requested
+    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how pointers to internal values of a
+    JSON value can be requested. Note that no type conversions are made and a
+    `nullptr` is returned if the value and the requested pointer type does not
+    match.,get__PointerType}
+
+    @sa @ref get_ptr() for explicit pointer-member access
+
+    @since version 1.0.0
+    */
+    template<typename PointerType, typename
+             std::enable_if<
+                 std::is_pointer<PointerType>::value
+                 , int>::type = 0>
+    PointerType get() noexcept
+    {
+        // delegate the call to get_ptr
+        return get_ptr<PointerType>();
+    }
+
+    /*!
+    @brief get a pointer value (explicit)
+    @copydoc get()
+    */
+    template<typename PointerType, typename
+             std::enable_if<
+                 std::is_pointer<PointerType>::value
+                 , int>::type = 0>
+    constexpr const PointerType get() const noexcept
+    {
+        // delegate the call to get_ptr
+        return get_ptr<PointerType>();
+    }
+
+    /*!
+    @brief get a pointer value (implicit)
+
+    Implicit pointer access to the internally stored JSON value. No copies are
+    made.
+
+    @warning Writing data to the pointee of the result yields an undefined
+    state.
+
+    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
+    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
+    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
+    assertion.
+
+    @return pointer to the internally stored JSON value if the requested
+    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how pointers to internal values of a
+    JSON value can be requested. Note that no type conversions are made and a
+    `nullptr` is returned if the value and the requested pointer type does not
+    match.,get_ptr}
+
+    @since version 1.0.0
+    */
+    template<typename PointerType, typename
+             std::enable_if<
+                 std::is_pointer<PointerType>::value
+                 , int>::type = 0>
+    PointerType get_ptr() noexcept
+    {
+        // get the type of the PointerType (remove pointer and const)
+        using pointee_t = typename std::remove_const<typename
+                          std::remove_pointer<typename
+                          std::remove_const<PointerType>::type>::type>::type;
+        // make sure the type matches the allowed types
+        static_assert(
+            std::is_same<object_t, pointee_t>::value
+            or std::is_same<array_t, pointee_t>::value
+            or std::is_same<string_t, pointee_t>::value
+            or std::is_same<boolean_t, pointee_t>::value
+            or std::is_same<number_integer_t, pointee_t>::value
+            or std::is_same<number_unsigned_t, pointee_t>::value
+            or std::is_same<number_float_t, pointee_t>::value
+            , "incompatible pointer type");
+
+        // delegate the call to get_impl_ptr<>()
+        return get_impl_ptr(static_cast<PointerType>(nullptr));
+    }
+
+    /*!
+    @brief get a pointer value (implicit)
+    @copydoc get_ptr()
+    */
+    template<typename PointerType, typename
+             std::enable_if<
+                 std::is_pointer<PointerType>::value
+                 and std::is_const<typename std::remove_pointer<PointerType>::type>::value
+                 , int>::type = 0>
+    constexpr const PointerType get_ptr() const noexcept
+    {
+        // get the type of the PointerType (remove pointer and const)
+        using pointee_t = typename std::remove_const<typename
+                          std::remove_pointer<typename
+                          std::remove_const<PointerType>::type>::type>::type;
+        // make sure the type matches the allowed types
+        static_assert(
+            std::is_same<object_t, pointee_t>::value
+            or std::is_same<array_t, pointee_t>::value
+            or std::is_same<string_t, pointee_t>::value
+            or std::is_same<boolean_t, pointee_t>::value
+            or std::is_same<number_integer_t, pointee_t>::value
+            or std::is_same<number_unsigned_t, pointee_t>::value
+            or std::is_same<number_float_t, pointee_t>::value
+            , "incompatible pointer type");
+
+        // delegate the call to get_impl_ptr<>() const
+        return get_impl_ptr(static_cast<const PointerType>(nullptr));
+    }
+
+    /*!
+    @brief get a reference value (implicit)
+
+    Implict reference access to the internally stored JSON value. No copies
+    are made.
+
+    @warning Writing data to the referee of the result yields an undefined
+    state.
+
+    @tparam ReferenceType reference type; must be a reference to @ref array_t,
+    @ref object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, or
+    @ref number_float_t. Enforced by static assertion.
+
+    @return reference to the internally stored JSON value if the requested
+    reference type @a ReferenceType fits to the JSON value; throws
+    std::domain_error otherwise
+
+    @throw std::domain_error in case passed type @a ReferenceType is
+    incompatible with the stored JSON value
+
+    @complexity Constant.
+
+    @liveexample{The example shows several calls to `get_ref()`.,get_ref}
+
+    @since version 1.1.0
+    */
+    template<typename ReferenceType, typename
+             std::enable_if<
+                 std::is_reference<ReferenceType>::value
+                 , int>::type = 0>
+    ReferenceType get_ref()
+    {
+        // delegate call to get_ref_impl
+        return get_ref_impl<ReferenceType>(*this);
+    }
+
+    /*!
+    @brief get a reference value (implicit)
+    @copydoc get_ref()
+    */
+    template<typename ReferenceType, typename
+             std::enable_if<
+                 std::is_reference<ReferenceType>::value
+                 and std::is_const<typename std::remove_reference<ReferenceType>::type>::value
+                 , int>::type = 0>
+    ReferenceType get_ref() const
+    {
+        // delegate call to get_ref_impl
+        return get_ref_impl<ReferenceType>(*this);
+    }
+
+    /*!
+    @brief get a value (implicit)
+
+    Implicit type conversion between the JSON value and a compatible value.
+    The call is realized by calling @ref get() const.
+
+    @tparam ValueType non-pointer type compatible to the JSON value, for
+    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
+    `std::vector` types for JSON arrays. The character type of @ref string_t
+    as well as an initializer list of this type is excluded to avoid
+    ambiguities as these types implicitly convert to `std::string`.
+
+    @return copy of the JSON value, converted to type @a ValueType
+
+    @throw std::domain_error in case passed type @a ValueType is incompatible
+    to JSON, thrown by @ref get() const
+
+    @complexity Linear in the size of the JSON value.
+
+    @liveexample{The example below shows several conversions from JSON values
+    to other types. There a few things to note: (1) Floating-point numbers can
+    be converted to integers\, (2) A JSON array can be converted to a standard
+    `std::vector<short>`\, (3) A JSON object can be converted to C++
+    associative containers such as `std::unordered_map<std::string\,
+    json>`.,operator__ValueType}
+
+    @since version 1.0.0
+    */
+    template < typename ValueType, typename
+               std::enable_if <
+                   not std::is_pointer<ValueType>::value
+                   and not std::is_same<ValueType, typename string_t::value_type>::value
+#ifndef _MSC_VER  // Fix for issue #167 operator<< abiguity under VS2015
+                   and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
+#endif
+                   , int >::type = 0 >
+    operator ValueType() const
+    {
+        // delegate the call to get<>() const
+        return get<ValueType>();
+    }
+
+    /// @}
+
+
+    ////////////////////
+    // element access //
+    ////////////////////
+
+    /// @name element access
+    /// Access to the JSON value.
+    /// @{
+
+    /*!
+    @brief access specified array element with bounds checking
+
+    Returns a reference to the element at specified location @a idx, with
+    bounds checking.
+
+    @param[in] idx  index of the element to access
+
+    @return reference to the element at index @a idx
+
+    @throw std::domain_error if the JSON value is not an array; example:
+    `"cannot use at() with string"`
+    @throw std::out_of_range if the index @a idx is out of range of the array;
+    that is, `idx >= size()`; example: `"array index 7 is out of range"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how array elements can be read and
+    written using `at()`.,at__size_type}
+
+    @since version 1.0.0
+    */
+    reference at(size_type idx)
+    {
+        // at only works for arrays
+        if (is_array())
+        {
+            try
+            {
+                return m_value.array->at(idx);
+            }
+            catch (std::out_of_range&)
+            {
+                // create better exception explanation
+                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use at() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified array element with bounds checking
+
+    Returns a const reference to the element at specified location @a idx,
+    with bounds checking.
+
+    @param[in] idx  index of the element to access
+
+    @return const reference to the element at index @a idx
+
+    @throw std::domain_error if the JSON value is not an array; example:
+    `"cannot use at() with string"`
+    @throw std::out_of_range if the index @a idx is out of range of the array;
+    that is, `idx >= size()`; example: `"array index 7 is out of range"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how array elements can be read using
+    `at()`.,at__size_type_const}
+
+    @since version 1.0.0
+    */
+    const_reference at(size_type idx) const
+    {
+        // at only works for arrays
+        if (is_array())
+        {
+            try
+            {
+                return m_value.array->at(idx);
+            }
+            catch (std::out_of_range&)
+            {
+                // create better exception explanation
+                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use at() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element with bounds checking
+
+    Returns a reference to the element at with specified key @a key, with
+    bounds checking.
+
+    @param[in] key  key of the element to access
+
+    @return reference to the element at key @a key
+
+    @throw std::domain_error if the JSON value is not an object; example:
+    `"cannot use at() with boolean"`
+    @throw std::out_of_range if the key @a key is is not stored in the object;
+    that is, `find(key) == end()`; example: `"key "the fast" not found"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using `at()`.,at__object_t_key_type}
+
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    reference at(const typename object_t::key_type& key)
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            try
+            {
+                return m_value.object->at(key);
+            }
+            catch (std::out_of_range&)
+            {
+                // create better exception explanation
+                throw std::out_of_range("key '" + key + "' not found");
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use at() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element with bounds checking
+
+    Returns a const reference to the element at with specified key @a key,
+    with bounds checking.
+
+    @param[in] key  key of the element to access
+
+    @return const reference to the element at key @a key
+
+    @throw std::domain_error if the JSON value is not an object; example:
+    `"cannot use at() with boolean"`
+    @throw std::out_of_range if the key @a key is is not stored in the object;
+    that is, `find(key) == end()`; example: `"key "the fast" not found"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    `at()`.,at__object_t_key_type_const}
+
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    const_reference at(const typename object_t::key_type& key) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            try
+            {
+                return m_value.object->at(key);
+            }
+            catch (std::out_of_range&)
+            {
+                // create better exception explanation
+                throw std::out_of_range("key '" + key + "' not found");
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use at() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified array element
+
+    Returns a reference to the element at specified location @a idx.
+
+    @note If @a idx is beyond the range of the array (i.e., `idx >= size()`),
+    then the array is silently filled up with `null` values to make `idx` a
+    valid reference to the last stored element.
+
+    @param[in] idx  index of the element to access
+
+    @return reference to the element at index @a idx
+
+    @throw std::domain_error if JSON is not an array or null; example:
+    `"cannot use operator[] with string"`
+
+    @complexity Constant if @a idx is in the range of the array. Otherwise
+    linear in `idx - size()`.
+
+    @liveexample{The example below shows how array elements can be read and
+    written using `[]` operator. Note the addition of `null`
+    values.,operatorarray__size_type}
+
+    @since version 1.0.0
+    */
+    reference operator[](size_type idx)
+    {
+        // implicitly convert null value to an empty array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value.array = create<array_t>();
+            assert_invariant();
+        }
+
+        // operator[] only works for arrays
+        if (is_array())
+        {
+            // fill up array with null values if given idx is outside range
+            if (idx >= m_value.array->size())
+            {
+                m_value.array->insert(m_value.array->end(),
+                                      idx - m_value.array->size() + 1,
+                                      basic_json());
+            }
+
+            return m_value.array->operator[](idx);
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified array element
+
+    Returns a const reference to the element at specified location @a idx.
+
+    @param[in] idx  index of the element to access
+
+    @return const reference to the element at index @a idx
+
+    @throw std::domain_error if JSON is not an array; example: `"cannot use
+    operator[] with null"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how array elements can be read using
+    the `[]` operator.,operatorarray__size_type_const}
+
+    @since version 1.0.0
+    */
+    const_reference operator[](size_type idx) const
+    {
+        // const operator[] only works for arrays
+        if (is_array())
+        {
+            return m_value.array->operator[](idx);
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element
+
+    Returns a reference to the element at with specified key @a key.
+
+    @note If @a key is not found in the object, then it is silently added to
+    the object and filled with a `null` value to make `key` a valid reference.
+    In case the value was `null` before, it is converted to an object.
+
+    @param[in] key  key of the element to access
+
+    @return reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object or null; example:
+    `"cannot use operator[] with string"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using the `[]` operator.,operatorarray__key_type}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    reference operator[](const typename object_t::key_type& key)
+    {
+        // implicitly convert null value to an empty object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value.object = create<object_t>();
+            assert_invariant();
+        }
+
+        // operator[] only works for objects
+        if (is_object())
+        {
+            return m_value.object->operator[](key);
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief read-only access specified object element
+
+    Returns a const reference to the element at with specified key @a key. No
+    bounds checking is performed.
+
+    @warning If the element with key @a key does not exist, the behavior is
+    undefined.
+
+    @param[in] key  key of the element to access
+
+    @return const reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    operator[] with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    the `[]` operator.,operatorarray__key_type_const}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    const_reference operator[](const typename object_t::key_type& key) const
+    {
+        // const operator[] only works for objects
+        if (is_object())
+        {
+            assert(m_value.object->find(key) != m_value.object->end());
+            return m_value.object->find(key)->second;
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element
+
+    Returns a reference to the element at with specified key @a key.
+
+    @note If @a key is not found in the object, then it is silently added to
+    the object and filled with a `null` value to make `key` a valid reference.
+    In case the value was `null` before, it is converted to an object.
+
+    @param[in] key  key of the element to access
+
+    @return reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object or null; example:
+    `"cannot use operator[] with string"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using the `[]` operator.,operatorarray__key_type}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    template<typename T, std::size_t n>
+    reference operator[](T * (&key)[n])
+    {
+        return operator[](static_cast<const T>(key));
+    }
+
+    /*!
+    @brief read-only access specified object element
+
+    Returns a const reference to the element at with specified key @a key. No
+    bounds checking is performed.
+
+    @warning If the element with key @a key does not exist, the behavior is
+    undefined.
+
+    @note This function is required for compatibility reasons with Clang.
+
+    @param[in] key  key of the element to access
+
+    @return const reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    operator[] with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    the `[]` operator.,operatorarray__key_type_const}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
+    */
+    template<typename T, std::size_t n>
+    const_reference operator[](T * (&key)[n]) const
+    {
+        return operator[](static_cast<const T>(key));
+    }
+
+    /*!
+    @brief access specified object element
+
+    Returns a reference to the element at with specified key @a key.
+
+    @note If @a key is not found in the object, then it is silently added to
+    the object and filled with a `null` value to make `key` a valid reference.
+    In case the value was `null` before, it is converted to an object.
+
+    @param[in] key  key of the element to access
+
+    @return reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object or null; example:
+    `"cannot use operator[] with string"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using the `[]` operator.,operatorarray__key_type}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.1.0
+    */
+    template<typename T>
+    reference operator[](T* key)
+    {
+        // implicitly convert null to object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value = value_t::object;
+            assert_invariant();
+        }
+
+        // at only works for objects
+        if (is_object())
+        {
+            return m_value.object->operator[](key);
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief read-only access specified object element
+
+    Returns a const reference to the element at with specified key @a key. No
+    bounds checking is performed.
+
+    @warning If the element with key @a key does not exist, the behavior is
+    undefined.
+
+    @param[in] key  key of the element to access
+
+    @return const reference to the element at key @a key
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    operator[] with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    the `[]` operator.,operatorarray__key_type_const}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.1.0
+    */
+    template<typename T>
+    const_reference operator[](T* key) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            assert(m_value.object->find(key) != m_value.object->end());
+            return m_value.object->find(key)->second;
+        }
+        else
+        {
+            throw std::domain_error("cannot use operator[] with " + type_name());
+        }
+    }
+
+    /*!
+    @brief access specified object element with default value
+
+    Returns either a copy of an object's element at the specified key @a key
+    or a given default value if no element with key @a key exists.
+
+    The function is basically equivalent to executing
+    @code {.cpp}
+    try {
+        return at(key);
+    } catch(std::out_of_range) {
+        return default_value;
+    }
+    @endcode
+
+    @note Unlike @ref at(const typename object_t::key_type&), this function
+    does not throw if the given key @a key was not found.
+
+    @note Unlike @ref operator[](const typename object_t::key_type& key), this
+    function does not implicitly add an element to the position defined by @a
+    key. This function is furthermore also applicable to const objects.
+
+    @param[in] key  key of the element to access
+    @param[in] default_value  the value to return if @a key is not found
+
+    @tparam ValueType type compatible to JSON values, for instance `int` for
+    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
+    JSON arrays. Note the type of the expected value at @a key and the default
+    value @a default_value must be compatible.
+
+    @return copy of the element at key @a key or @a default_value if @a key
+    is not found
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    value() with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be queried
+    with a default value.,basic_json__value}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
+
+    @since version 1.0.0
+    */
+    template <class ValueType, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, ValueType>::value
+                  , int>::type = 0>
+    ValueType value(const typename object_t::key_type& key, ValueType default_value) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            // if key is found, return value and given default value otherwise
+            const auto it = find(key);
+            if (it != end())
+            {
+                return *it;
+            }
+            else
+            {
+                return default_value;
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use value() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief overload for a default value of type const char*
+    @copydoc basic_json::value(const typename object_t::key_type&, ValueType) const
+    */
+    string_t value(const typename object_t::key_type& key, const char* default_value) const
+    {
+        return value(key, string_t(default_value));
+    }
+
+    /*!
+    @brief access specified object element via JSON Pointer with default value
+
+    Returns either a copy of an object's element at the specified key @a key
+    or a given default value if no element with key @a key exists.
+
+    The function is basically equivalent to executing
+    @code {.cpp}
+    try {
+        return at(ptr);
+    } catch(std::out_of_range) {
+        return default_value;
+    }
+    @endcode
+
+    @note Unlike @ref at(const json_pointer&), this function does not throw
+    if the given key @a key was not found.
+
+    @param[in] ptr  a JSON pointer to the element to access
+    @param[in] default_value  the value to return if @a ptr found no value
+
+    @tparam ValueType type compatible to JSON values, for instance `int` for
+    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
+    JSON arrays. Note the type of the expected value at @a key and the default
+    value @a default_value must be compatible.
+
+    @return copy of the element at key @a key or @a default_value if @a key
+    is not found
+
+    @throw std::domain_error if JSON is not an object; example: `"cannot use
+    value() with null"`
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be queried
+    with a default value.,basic_json__value_ptr}
+
+    @sa @ref operator[](const json_pointer&) for unchecked access by reference
+
+    @since version 2.0.2
+    */
+    template <class ValueType, typename
+              std::enable_if<
+                  std::is_convertible<basic_json_t, ValueType>::value
+                  , int>::type = 0>
+    ValueType value(const json_pointer& ptr, ValueType default_value) const
+    {
+        // at only works for objects
+        if (is_object())
+        {
+            // if pointer resolves a value, return it or use default value
+            try
+            {
+                return ptr.get_checked(this);
+            }
+            catch (std::out_of_range&)
+            {
+                return default_value;
+            }
+        }
+        else
+        {
+            throw std::domain_error("cannot use value() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief overload for a default value of type const char*
+    @copydoc basic_json::value(const json_pointer&, ValueType) const
+    */
+    string_t value(const json_pointer& ptr, const char* default_value) const
+    {
+        return value(ptr, string_t(default_value));
+    }
+
+    /*!
+    @brief access the first element
+
+    Returns a reference to the first element in the container. For a JSON
+    container `c`, the expression `c.front()` is equivalent to `*c.begin()`.
+
+    @return In case of a structured type (array or object), a reference to the
+    first element is returned. In cast of number, string, or boolean values, a
+    reference to the value is returned.
+
+    @complexity Constant.
+
+    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
+    or an empty array or object (undefined behavior, guarded by assertions).
+    @post The JSON value remains unchanged.
+
+    @throw std::out_of_range when called on `null` value
+
+    @liveexample{The following code shows an example for `front()`.,front}
+
+    @sa @ref back() -- access the last element
+
+    @since version 1.0.0
+    */
+    reference front()
+    {
+        return *begin();
+    }
+
+    /*!
+    @copydoc basic_json::front()
+    */
+    const_reference front() const
+    {
+        return *cbegin();
+    }
+
+    /*!
+    @brief access the last element
+
+    Returns a reference to the last element in the container. For a JSON
+    container `c`, the expression `c.back()` is equivalent to
+    @code {.cpp}
+    auto tmp = c.end();
+    --tmp;
+    return *tmp;
+    @endcode
+
+    @return In case of a structured type (array or object), a reference to the
+    last element is returned. In cast of number, string, or boolean values, a
+    reference to the value is returned.
+
+    @complexity Constant.
+
+    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
+    or an empty array or object (undefined behavior, guarded by assertions).
+    @post The JSON value remains unchanged.
+
+    @throw std::out_of_range when called on `null` value.
+
+    @liveexample{The following code shows an example for `back()`.,back}
+
+    @sa @ref front() -- access the first element
+
+    @since version 1.0.0
+    */
+    reference back()
+    {
+        auto tmp = end();
+        --tmp;
+        return *tmp;
+    }
+
+    /*!
+    @copydoc basic_json::back()
+    */
+    const_reference back() const
+    {
+        auto tmp = cend();
+        --tmp;
+        return *tmp;
+    }
+
+    /*!
+    @brief remove element given an iterator
+
+    Removes the element specified by iterator @a pos. The iterator @a pos must
+    be valid and dereferenceable. Thus the `end()` iterator (which is valid,
+    but is not dereferenceable) cannot be used as a value for @a pos.
+
+    If called on a primitive type other than `null`, the resulting JSON value
+    will be `null`.
+
+    @param[in] pos iterator to the element to remove
+    @return Iterator following the last removed element. If the iterator @a
+    pos refers to the last element, the `end()` iterator is returned.
+
+    @tparam InteratorType an @ref iterator or @ref const_iterator
+
+    @post Invalidates iterators and references at or after the point of the
+    erase, including the `end()` iterator.
+
+    @throw std::domain_error if called on a `null` value; example: `"cannot
+    use erase() with null"`
+    @throw std::domain_error if called on an iterator which does not belong to
+    the current JSON value; example: `"iterator does not fit current value"`
+    @throw std::out_of_range if called on a primitive type with invalid
+    iterator (i.e., any iterator which is not `begin()`); example: `"iterator
+    out of range"`
+
+    @complexity The complexity depends on the type:
+    - objects: amortized constant
+    - arrays: linear in distance between pos and the end of the container
+    - strings: linear in the length of the string
+    - other types: constant
+
+    @liveexample{The example shows the result of `erase()` for different JSON
+    types.,erase__IteratorType}
+
+    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
+
+    @since version 1.0.0
+    */
+    template <class InteratorType, typename
+              std::enable_if<
+                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
+                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
+                  , int>::type
+              = 0>
+    InteratorType erase(InteratorType pos)
+    {
+        // make sure iterator fits the current value
+        if (this != pos.m_object)
+        {
+            throw std::domain_error("iterator does not fit current value");
+        }
+
+        InteratorType result = end();
+
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
+            {
+                if (not pos.m_it.primitive_iterator.is_begin())
+                {
+                    throw std::out_of_range("iterator out of range");
+                }
+
+                if (is_string())
+                {
+                    AllocatorType<string_t> alloc;
+                    alloc.destroy(m_value.string);
+                    alloc.deallocate(m_value.string, 1);
+                    m_value.string = nullptr;
+                }
+
+                m_type = value_t::null;
+                assert_invariant();
+                break;
+            }
+
+            case value_t::object:
+            {
+                result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator);
+                break;
+            }
+
+            case value_t::array:
+            {
+                result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator);
+                break;
+            }
+
+            default:
+            {
+                throw std::domain_error("cannot use erase() with " + type_name());
+            }
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief remove elements given an iterator range
+
+    Removes the element specified by the range `[first; last)`. The iterator
+    @a first does not need to be dereferenceable if `first == last`: erasing
+    an empty range is a no-op.
+
+    If called on a primitive type other than `null`, the resulting JSON value
+    will be `null`.
+
+    @param[in] first iterator to the beginning of the range to remove
+    @param[in] last iterator past the end of the range to remove
+    @return Iterator following the last removed element. If the iterator @a
+    second refers to the last element, the `end()` iterator is returned.
+
+    @tparam InteratorType an @ref iterator or @ref const_iterator
+
+    @post Invalidates iterators and references at or after the point of the
+    erase, including the `end()` iterator.
+
+    @throw std::domain_error if called on a `null` value; example: `"cannot
+    use erase() with null"`
+    @throw std::domain_error if called on iterators which does not belong to
+    the current JSON value; example: `"iterators do not fit current value"`
+    @throw std::out_of_range if called on a primitive type with invalid
+    iterators (i.e., if `first != begin()` and `last != end()`); example:
+    `"iterators out of range"`
+
+    @complexity The complexity depends on the type:
+    - objects: `log(size()) + std::distance(first, last)`
+    - arrays: linear in the distance between @a first and @a last, plus linear
+      in the distance between @a last and end of the container
+    - strings: linear in the length of the string
+    - other types: constant
+
+    @liveexample{The example shows the result of `erase()` for different JSON
+    types.,erase__IteratorType_IteratorType}
+
+    @sa @ref erase(InteratorType) -- removes the element at a given position
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
+
+    @since version 1.0.0
+    */
+    template <class InteratorType, typename
+              std::enable_if<
+                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
+                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
+                  , int>::type
+              = 0>
+    InteratorType erase(InteratorType first, InteratorType last)
+    {
+        // make sure iterator fits the current value
+        if (this != first.m_object or this != last.m_object)
+        {
+            throw std::domain_error("iterators do not fit current value");
+        }
+
+        InteratorType result = end();
+
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
+            {
+                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
+                {
+                    throw std::out_of_range("iterators out of range");
+                }
+
+                if (is_string())
+                {
+                    AllocatorType<string_t> alloc;
+                    alloc.destroy(m_value.string);
+                    alloc.deallocate(m_value.string, 1);
+                    m_value.string = nullptr;
+                }
+
+                m_type = value_t::null;
+                assert_invariant();
+                break;
+            }
+
+            case value_t::object:
+            {
+                result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator,
+                                              last.m_it.object_iterator);
+                break;
+            }
+
+            case value_t::array:
+            {
+                result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator,
+                                             last.m_it.array_iterator);
+                break;
+            }
+
+            default:
+            {
+                throw std::domain_error("cannot use erase() with " + type_name());
+            }
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief remove element from a JSON object given a key
+
+    Removes elements from a JSON object with the key value @a key.
+
+    @param[in] key value of the elements to remove
+
+    @return Number of elements removed. If @a ObjectType is the default
+    `std::map` type, the return value will always be `0` (@a key was not
+    found) or `1` (@a key was found).
+
+    @post References and iterators to the erased elements are invalidated.
+    Other references and iterators are not affected.
+
+    @throw std::domain_error when called on a type other than JSON object;
+    example: `"cannot use erase() with null"`
+
+    @complexity `log(size()) + count(key)`
+
+    @liveexample{The example shows the effect of `erase()`.,erase__key_type}
+
+    @sa @ref erase(InteratorType) -- removes the element at a given position
+    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
+
+    @since version 1.0.0
+    */
+    size_type erase(const typename object_t::key_type& key)
+    {
+        // this erase only works for objects
+        if (is_object())
+        {
+            return m_value.object->erase(key);
+        }
+        else
+        {
+            throw std::domain_error("cannot use erase() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief remove element from a JSON array given an index
+
+    Removes element from a JSON array at the index @a idx.
+
+    @param[in] idx index of the element to remove
+
+    @throw std::domain_error when called on a type other than JSON array;
+    example: `"cannot use erase() with null"`
+    @throw std::out_of_range when `idx >= size()`; example: `"array index 17
+    is out of range"`
+
+    @complexity Linear in distance between @a idx and the end of the container.
+
+    @liveexample{The example shows the effect of `erase()`.,erase__size_type}
+
+    @sa @ref erase(InteratorType) -- removes the element at a given position
+    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+
+    @since version 1.0.0
+    */
+    void erase(const size_type idx)
+    {
+        // this erase only works for arrays
+        if (is_array())
+        {
+            if (idx >= size())
+            {
+                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+            }
+
+            m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
+        }
+        else
+        {
+            throw std::domain_error("cannot use erase() with " + type_name());
+        }
+    }
+
+    /// @}
+
+
+    ////////////
+    // lookup //
+    ////////////
+
+    /// @name lookup
+    /// @{
+
+    /*!
+    @brief find an element in a JSON object
+
+    Finds an element in a JSON object with key equivalent to @a key. If the
+    element is not found or the JSON value is not an object, end() is
+    returned.
+
+    @param[in] key key value of the element to search for
+
+    @return Iterator to an element with key equivalent to @a key. If no such
+    element is found, past-the-end (see end()) iterator is returned.
+
+    @complexity Logarithmic in the size of the JSON object.
+
+    @liveexample{The example shows how `find()` is used.,find__key_type}
+
+    @since version 1.0.0
+    */
+    iterator find(typename object_t::key_type key)
+    {
+        auto result = end();
+
+        if (is_object())
+        {
+            result.m_it.object_iterator = m_value.object->find(key);
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief find an element in a JSON object
+    @copydoc find(typename object_t::key_type)
+    */
+    const_iterator find(typename object_t::key_type key) const
+    {
+        auto result = cend();
+
+        if (is_object())
+        {
+            result.m_it.object_iterator = m_value.object->find(key);
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief returns the number of occurrences of a key in a JSON object
+
+    Returns the number of elements with key @a key. If ObjectType is the
+    default `std::map` type, the return value will always be `0` (@a key was
+    not found) or `1` (@a key was found).
+
+    @param[in] key key value of the element to count
+
+    @return Number of elements with key @a key. If the JSON value is not an
+    object, the return value will be `0`.
+
+    @complexity Logarithmic in the size of the JSON object.
+
+    @liveexample{The example shows how `count()` is used.,count}
+
+    @since version 1.0.0
+    */
+    size_type count(typename object_t::key_type key) const
+    {
+        // return 0 for all nonobject types
+        return is_object() ? m_value.object->count(key) : 0;
+    }
+
+    /// @}
+
+
+    ///////////////
+    // iterators //
+    ///////////////
+
+    /// @name iterators
+    /// @{
+
+    /*!
+    @brief returns an iterator to the first element
+
+    Returns an iterator to the first element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return iterator to the first element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+
+    @liveexample{The following code shows an example for `begin()`.,begin}
+
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref cend() -- returns a const iterator to the end
+
+    @since version 1.0.0
+    */
+    iterator begin() noexcept
+    {
+        iterator result(this);
+        result.set_begin();
+        return result;
+    }
+
+    /*!
+    @copydoc basic_json::cbegin()
+    */
+    const_iterator begin() const noexcept
+    {
+        return cbegin();
+    }
+
+    /*!
+    @brief returns a const iterator to the first element
+
+    Returns a const iterator to the first element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return const iterator to the first element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).begin()`.
+
+    @liveexample{The following code shows an example for `cbegin()`.,cbegin}
+
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref cend() -- returns a const iterator to the end
+
+    @since version 1.0.0
+    */
+    const_iterator cbegin() const noexcept
+    {
+        const_iterator result(this);
+        result.set_begin();
+        return result;
+    }
+
+    /*!
+    @brief returns an iterator to one past the last element
+
+    Returns an iterator to one past the last element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return iterator one past the last element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+
+    @liveexample{The following code shows an example for `end()`.,end}
+
+    @sa @ref cend() -- returns a const iterator to the end
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+
+    @since version 1.0.0
+    */
+    iterator end() noexcept
+    {
+        iterator result(this);
+        result.set_end();
+        return result;
+    }
+
+    /*!
+    @copydoc basic_json::cend()
+    */
+    const_iterator end() const noexcept
+    {
+        return cend();
+    }
+
+    /*!
+    @brief returns a const iterator to one past the last element
+
+    Returns a const iterator to one past the last element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return const iterator one past the last element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).end()`.
+
+    @liveexample{The following code shows an example for `cend()`.,cend}
+
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+
+    @since version 1.0.0
+    */
+    const_iterator cend() const noexcept
+    {
+        const_iterator result(this);
+        result.set_end();
+        return result;
+    }
+
+    /*!
+    @brief returns an iterator to the reverse-beginning
+
+    Returns an iterator to the reverse-beginning; that is, the last element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `reverse_iterator(end())`.
+
+    @liveexample{The following code shows an example for `rbegin()`.,rbegin}
+
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref crend() -- returns a const reverse iterator to the end
+
+    @since version 1.0.0
+    */
+    reverse_iterator rbegin() noexcept
+    {
+        return reverse_iterator(end());
+    }
+
+    /*!
+    @copydoc basic_json::crbegin()
+    */
+    const_reverse_iterator rbegin() const noexcept
+    {
+        return crbegin();
+    }
+
+    /*!
+    @brief returns an iterator to the reverse-end
+
+    Returns an iterator to the reverse-end; that is, one before the first
+    element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `reverse_iterator(begin())`.
+
+    @liveexample{The following code shows an example for `rend()`.,rend}
+
+    @sa @ref crend() -- returns a const reverse iterator to the end
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+
+    @since version 1.0.0
+    */
+    reverse_iterator rend() noexcept
+    {
+        return reverse_iterator(begin());
+    }
+
+    /*!
+    @copydoc basic_json::crend()
+    */
+    const_reverse_iterator rend() const noexcept
+    {
+        return crend();
+    }
+
+    /*!
+    @brief returns a const reverse iterator to the last element
+
+    Returns a const iterator to the reverse-beginning; that is, the last
+    element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).rbegin()`.
+
+    @liveexample{The following code shows an example for `crbegin()`.,crbegin}
+
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref crend() -- returns a const reverse iterator to the end
+
+    @since version 1.0.0
+    */
+    const_reverse_iterator crbegin() const noexcept
+    {
+        return const_reverse_iterator(cend());
+    }
+
+    /*!
+    @brief returns a const reverse iterator to one before the first
+
+    Returns a const reverse iterator to the reverse-end; that is, one before
+    the first element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).rend()`.
+
+    @liveexample{The following code shows an example for `crend()`.,crend}
+
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+
+    @since version 1.0.0
+    */
+    const_reverse_iterator crend() const noexcept
+    {
+        return const_reverse_iterator(cbegin());
+    }
+
+  private:
+    // forward declaration
+    template<typename IteratorType> class iteration_proxy;
+
+  public:
+    /*!
+    @brief wrapper to access iterator member functions in range-based for
+
+    This function allows to access @ref iterator::key() and @ref
+    iterator::value() during range-based for loops. In these loops, a
+    reference to the JSON values is returned, so there is no access to the
+    underlying iterator.
+
+    @note The name of this function is not yet final and may change in the
+    future.
+    */
+    static iteration_proxy<iterator> iterator_wrapper(reference cont)
+    {
+        return iteration_proxy<iterator>(cont);
+    }
+
+    /*!
+    @copydoc iterator_wrapper(reference)
+    */
+    static iteration_proxy<const_iterator> iterator_wrapper(const_reference cont)
+    {
+        return iteration_proxy<const_iterator>(cont);
+    }
+
+    /// @}
+
+
+    //////////////
+    // capacity //
+    //////////////
+
+    /// @name capacity
+    /// @{
+
+    /*!
+    @brief checks whether the container is empty
+
+    Checks if a JSON value has no elements.
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `true`
+            boolean     | `false`
+            string      | `false`
+            number      | `false`
+            object      | result of function `object_t::empty()`
+            array       | result of function `array_t::empty()`
+
+    @note This function does not return whether a string stored as JSON value
+    is empty - it returns whether the JSON container itself is empty which is
+    false in the case of a string.
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their `empty()` functions have constant
+    complexity.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `begin() == end()`.
+
+    @liveexample{The following code uses `empty()` to check if a JSON
+    object contains any elements.,empty}
+
+    @sa @ref size() -- returns the number of elements
+
+    @since version 1.0.0
+    */
+    bool empty() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+            {
+                // null values are empty
+                return true;
+            }
+
+            case value_t::array:
+            {
+                // delegate call to array_t::empty()
+                return m_value.array->empty();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::empty()
+                return m_value.object->empty();
+            }
+
+            default:
+            {
+                // all other types are nonempty
+                return false;
+            }
+        }
+    }
+
+    /*!
+    @brief returns the number of elements
+
+    Returns the number of elements in a JSON value.
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `0`
+            boolean     | `1`
+            string      | `1`
+            number      | `1`
+            object      | result of function object_t::size()
+            array       | result of function array_t::size()
+
+    @note This function does not return the length of a string stored as JSON
+    value - it returns the number of elements in the JSON value which is 1 in
+    the case of a string.
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their size() functions have constant
+    complexity.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `std::distance(begin(), end())`.
+
+    @liveexample{The following code calls `size()` on the different value
+    types.,size}
+
+    @sa @ref empty() -- checks whether the container is empty
+    @sa @ref max_size() -- returns the maximal number of elements
+
+    @since version 1.0.0
+    */
+    size_type size() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+            {
+                // null values are empty
+                return 0;
+            }
+
+            case value_t::array:
+            {
+                // delegate call to array_t::size()
+                return m_value.array->size();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::size()
+                return m_value.object->size();
+            }
+
+            default:
+            {
+                // all other types have size 1
+                return 1;
+            }
+        }
+    }
+
+    /*!
+    @brief returns the maximum possible number of elements
+
+    Returns the maximum number of elements a JSON value is able to hold due to
+    system or library implementation limitations, i.e. `std::distance(begin(),
+    end())` for the JSON value.
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `0` (same as `size()`)
+            boolean     | `1` (same as `size()`)
+            string      | `1` (same as `size()`)
+            number      | `1` (same as `size()`)
+            object      | result of function `object_t::max_size()`
+            array       | result of function `array_t::max_size()`
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their `max_size()` functions have constant
+    complexity.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of returning `b.size()` where `b` is the largest
+      possible JSON value.
+
+    @liveexample{The following code calls `max_size()` on the different value
+    types. Note the output is implementation specific.,max_size}
+
+    @sa @ref size() -- returns the number of elements
+
+    @since version 1.0.0
+    */
+    size_type max_size() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::array:
+            {
+                // delegate call to array_t::max_size()
+                return m_value.array->max_size();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::max_size()
+                return m_value.object->max_size();
+            }
+
+            default:
+            {
+                // all other types have max_size() == size()
+                return size();
+            }
+        }
+    }
+
+    /// @}
+
+
+    ///////////////
+    // modifiers //
+    ///////////////
+
+    /// @name modifiers
+    /// @{
+
+    /*!
+    @brief clears the contents
+
+    Clears the content of a JSON value and resets it to the default value as
+    if @ref basic_json(value_t) would have been called:
+
+    Value type  | initial value
+    ----------- | -------------
+    null        | `null`
+    boolean     | `false`
+    string      | `""`
+    number      | `0`
+    object      | `{}`
+    array       | `[]`
+
+    @note Floating-point numbers are set to `0.0` which will be serialized to
+    `0`. The vale type remains @ref number_float_t.
+
+    @complexity Linear in the size of the JSON value.
+
+    @liveexample{The example below shows the effect of `clear()` to different
+    JSON types.,clear}
+
+    @since version 1.0.0
+    */
+    void clear() noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::number_integer:
+            {
+                m_value.number_integer = 0;
+                break;
+            }
+
+            case value_t::number_unsigned:
+            {
+                m_value.number_unsigned = 0;
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                m_value.number_float = 0.0;
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                m_value.boolean = false;
+                break;
+            }
+
+            case value_t::string:
+            {
+                m_value.string->clear();
+                break;
+            }
+
+            case value_t::array:
+            {
+                m_value.array->clear();
+                break;
+            }
+
+            case value_t::object:
+            {
+                m_value.object->clear();
+                break;
+            }
+
+            default:
+            {
+                break;
+            }
+        }
+    }
+
+    /*!
+    @brief add an object to an array
+
+    Appends the given element @a val to the end of the JSON value. If the
+    function is called on a JSON null value, an empty array is created before
+    appending @a val.
+
+    @param[in] val the value to add to the JSON array
+
+    @throw std::domain_error when called on a type other than JSON array or
+    null; example: `"cannot use push_back() with number"`
+
+    @complexity Amortized constant.
+
+    @liveexample{The example shows how `push_back()` and `+=` can be used to
+    add elements to a JSON array. Note how the `null` value was silently
+    converted to a JSON array.,push_back}
+
+    @since version 1.0.0
+    */
+    void push_back(basic_json&& val)
+    {
+        // push_back only works for null objects or arrays
+        if (not(is_null() or is_array()))
+        {
+            throw std::domain_error("cannot use push_back() with " + type_name());
+        }
+
+        // transform null object into an array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value = value_t::array;
+            assert_invariant();
+        }
+
+        // add element to array (move semantics)
+        m_value.array->push_back(std::move(val));
+        // invalidate object
+        val.m_type = value_t::null;
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    reference operator+=(basic_json&& val)
+    {
+        push_back(std::move(val));
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    void push_back(const basic_json& val)
+    {
+        // push_back only works for null objects or arrays
+        if (not(is_null() or is_array()))
+        {
+            throw std::domain_error("cannot use push_back() with " + type_name());
+        }
+
+        // transform null object into an array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value = value_t::array;
+            assert_invariant();
+        }
+
+        // add element to array
+        m_value.array->push_back(val);
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    reference operator+=(const basic_json& val)
+    {
+        push_back(val);
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an object
+
+    Inserts the given element @a val to the JSON object. If the function is
+    called on a JSON null value, an empty object is created before inserting
+    @a val.
+
+    @param[in] val the value to add to the JSON object
+
+    @throw std::domain_error when called on a type other than JSON object or
+    null; example: `"cannot use push_back() with number"`
+
+    @complexity Logarithmic in the size of the container, O(log(`size()`)).
+
+    @liveexample{The example shows how `push_back()` and `+=` can be used to
+    add elements to a JSON object. Note how the `null` value was silently
+    converted to a JSON object.,push_back__object_t__value}
+
+    @since version 1.0.0
+    */
+    void push_back(const typename object_t::value_type& val)
+    {
+        // push_back only works for null objects or objects
+        if (not(is_null() or is_object()))
+        {
+            throw std::domain_error("cannot use push_back() with " + type_name());
+        }
+
+        // transform null object into an object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value = value_t::object;
+            assert_invariant();
+        }
+
+        // add element to array
+        m_value.object->insert(val);
+    }
+
+    /*!
+    @brief add an object to an object
+    @copydoc push_back(const typename object_t::value_type&)
+    */
+    reference operator+=(const typename object_t::value_type& val)
+    {
+        push_back(val);
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an object
+
+    This function allows to use `push_back` with an initializer list. In case
+
+    1. the current value is an object,
+    2. the initializer list @a init contains only two elements, and
+    3. the first element of @a init is a string,
+
+    @a init is converted into an object element and added using
+    @ref push_back(const typename object_t::value_type&). Otherwise, @a init
+    is converted to a JSON value and added using @ref push_back(basic_json&&).
+
+    @param init  an initializer list
+
+    @complexity Linear in the size of the initializer list @a init.
+
+    @note This function is required to resolve an ambiguous overload error,
+          because pairs like `{"key", "value"}` can be both interpreted as
+          `object_t::value_type` or `std::initializer_list<basic_json>`, see
+          https://github.com/nlohmann/json/issues/235 for more information.
+
+    @liveexample{The example shows how initializer lists are treated as
+    objects when possible.,push_back__initializer_list}
+    */
+    void push_back(std::initializer_list<basic_json> init)
+    {
+        if (is_object() and init.size() == 2 and init.begin()->is_string())
+        {
+            const string_t key = *init.begin();
+            push_back(typename object_t::value_type(key, *(init.begin() + 1)));
+        }
+        else
+        {
+            push_back(basic_json(init));
+        }
+    }
+
+    /*!
+    @brief add an object to an object
+    @copydoc push_back(std::initializer_list<basic_json>)
+    */
+    reference operator+=(std::initializer_list<basic_json> init)
+    {
+        push_back(init);
+        return *this;
+    }
+
+    /*!
+    @brief inserts element
+
+    Inserts element @a val before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] val element to insert
+    @return iterator pointing to the inserted @a val.
+
+    @throw std::domain_error if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw std::domain_error if @a pos is not an iterator of *this; example:
+    `"iterator does not fit current value"`
+
+    @complexity Constant plus linear in the distance between pos and end of the
+    container.
+
+    @liveexample{The example shows how `insert()` is used.,insert}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, const basic_json& val)
+    {
+        // insert only works for arrays
+        if (is_array())
+        {
+            // check if iterator pos fits to this JSON value
+            if (pos.m_object != this)
+            {
+                throw std::domain_error("iterator does not fit current value");
+            }
+
+            // insert to array and return iterator
+            iterator result(this);
+            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
+            return result;
+        }
+        else
+        {
+            throw std::domain_error("cannot use insert() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief inserts element
+    @copydoc insert(const_iterator, const basic_json&)
+    */
+    iterator insert(const_iterator pos, basic_json&& val)
+    {
+        return insert(pos, val);
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts @a cnt copies of @a val before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] cnt number of copies of @a val to insert
+    @param[in] val element to insert
+    @return iterator pointing to the first element inserted, or @a pos if
+    `cnt==0`
+
+    @throw std::domain_error if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw std::domain_error if @a pos is not an iterator of *this; example:
+    `"iterator does not fit current value"`
+
+    @complexity Linear in @a cnt plus linear in the distance between @a pos
+    and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__count}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, size_type cnt, const basic_json& val)
+    {
+        // insert only works for arrays
+        if (is_array())
+        {
+            // check if iterator pos fits to this JSON value
+            if (pos.m_object != this)
+            {
+                throw std::domain_error("iterator does not fit current value");
+            }
+
+            // insert to array and return iterator
+            iterator result(this);
+            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
+            return result;
+        }
+        else
+        {
+            throw std::domain_error("cannot use insert() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts elements from range `[first, last)` before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] first begin of the range of elements to insert
+    @param[in] last end of the range of elements to insert
+
+    @throw std::domain_error if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw std::domain_error if @a pos is not an iterator of *this; example:
+    `"iterator does not fit current value"`
+    @throw std::domain_error if @a first and @a last do not belong to the same
+    JSON value; example: `"iterators do not fit"`
+    @throw std::domain_error if @a first or @a last are iterators into
+    container for which insert is called; example: `"passed iterators may not
+    belong to container"`
+
+    @return iterator pointing to the first element inserted, or @a pos if
+    `first==last`
+
+    @complexity Linear in `std::distance(first, last)` plus linear in the
+    distance between @a pos and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__range}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, const_iterator first, const_iterator last)
+    {
+        // insert only works for arrays
+        if (not is_array())
+        {
+            throw std::domain_error("cannot use insert() with " + type_name());
+        }
+
+        // check if iterator pos fits to this JSON value
+        if (pos.m_object != this)
+        {
+            throw std::domain_error("iterator does not fit current value");
+        }
+
+        // check if range iterators belong to the same JSON object
+        if (first.m_object != last.m_object)
+        {
+            throw std::domain_error("iterators do not fit");
+        }
+
+        if (first.m_object == this or last.m_object == this)
+        {
+            throw std::domain_error("passed iterators may not belong to container");
+        }
+
+        // insert to array and return iterator
+        iterator result(this);
+        result.m_it.array_iterator = m_value.array->insert(
+                                         pos.m_it.array_iterator,
+                                         first.m_it.array_iterator,
+                                         last.m_it.array_iterator);
+        return result;
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts elements from initializer list @a ilist before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] ilist initializer list to insert the values from
+
+    @throw std::domain_error if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw std::domain_error if @a pos is not an iterator of *this; example:
+    `"iterator does not fit current value"`
+
+    @return iterator pointing to the first element inserted, or @a pos if
+    `ilist` is empty
+
+    @complexity Linear in `ilist.size()` plus linear in the distance between
+    @a pos and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__ilist}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, std::initializer_list<basic_json> ilist)
+    {
+        // insert only works for arrays
+        if (not is_array())
+        {
+            throw std::domain_error("cannot use insert() with " + type_name());
+        }
+
+        // check if iterator pos fits to this JSON value
+        if (pos.m_object != this)
+        {
+            throw std::domain_error("iterator does not fit current value");
+        }
+
+        // insert to array and return iterator
+        iterator result(this);
+        result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, ilist);
+        return result;
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of the JSON value with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other JSON value to exchange the contents with
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how JSON values can be swapped with
+    `swap()`.,swap__reference}
+
+    @since version 1.0.0
+    */
+    void swap(reference other) noexcept (
+        std::is_nothrow_move_constructible<value_t>::value and
+        std::is_nothrow_move_assignable<value_t>::value and
+        std::is_nothrow_move_constructible<json_value>::value and
+        std::is_nothrow_move_assignable<json_value>::value
+    )
+    {
+        std::swap(m_type, other.m_type);
+        std::swap(m_value, other.m_value);
+        assert_invariant();
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON array with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other array to exchange the contents with
+
+    @throw std::domain_error when JSON value is not an array; example: `"cannot
+    use swap() with string"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how arrays can be swapped with
+    `swap()`.,swap__array_t}
+
+    @since version 1.0.0
+    */
+    void swap(array_t& other)
+    {
+        // swap only works for arrays
+        if (is_array())
+        {
+            std::swap(*(m_value.array), other);
+        }
+        else
+        {
+            throw std::domain_error("cannot use swap() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON object with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other object to exchange the contents with
+
+    @throw std::domain_error when JSON value is not an object; example:
+    `"cannot use swap() with string"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how objects can be swapped with
+    `swap()`.,swap__object_t}
+
+    @since version 1.0.0
+    */
+    void swap(object_t& other)
+    {
+        // swap only works for objects
+        if (is_object())
+        {
+            std::swap(*(m_value.object), other);
+        }
+        else
+        {
+            throw std::domain_error("cannot use swap() with " + type_name());
+        }
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON string with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other string to exchange the contents with
+
+    @throw std::domain_error when JSON value is not a string; example: `"cannot
+    use swap() with boolean"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how strings can be swapped with
+    `swap()`.,swap__string_t}
+
+    @since version 1.0.0
+    */
+    void swap(string_t& other)
+    {
+        // swap only works for strings
+        if (is_string())
+        {
+            std::swap(*(m_value.string), other);
+        }
+        else
+        {
+            throw std::domain_error("cannot use swap() with " + type_name());
+        }
+    }
+
+    /// @}
+
+
+    //////////////////////////////////////////
+    // lexicographical comparison operators //
+    //////////////////////////////////////////
+
+    /// @name lexicographical comparison operators
+    /// @{
+
+  private:
+    /*!
+    @brief comparison operator for JSON types
+
+    Returns an ordering that is similar to Python:
+    - order: null < boolean < number < object < array < string
+    - furthermore, each type is not smaller than itself
+
+    @since version 1.0.0
+    */
+    friend bool operator<(const value_t lhs, const value_t rhs) noexcept
+    {
+        static constexpr std::array<uint8_t, 8> order = {{
+                0, // null
+                3, // object
+                4, // array
+                5, // string
+                1, // boolean
+                2, // integer
+                2, // unsigned
+                2, // float
+            }
+        };
+
+        // discarded values are not comparable
+        if (lhs == value_t::discarded or rhs == value_t::discarded)
+        {
+            return false;
+        }
+
+        return order[static_cast<std::size_t>(lhs)] < order[static_cast<std::size_t>(rhs)];
+    }
+
+  public:
+    /*!
+    @brief comparison: equal
+
+    Compares two JSON values for equality according to the following rules:
+    - Two JSON values are equal if (1) they are from the same type and (2)
+      their stored values are the same.
+    - Integer and floating-point numbers are automatically converted before
+      comparison. Floating-point numbers are compared indirectly: two
+      floating-point numbers `f1` and `f2` are considered equal if neither
+      `f1 > f2` nor `f2 > f1` holds.
+    - Two JSON null values are equal.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether the values @a lhs and @a rhs are equal
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__equal}
+
+    @since version 1.0.0
+    */
+    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
+    {
+        const auto lhs_type = lhs.type();
+        const auto rhs_type = rhs.type();
+
+        if (lhs_type == rhs_type)
+        {
+            switch (lhs_type)
+            {
+                case value_t::array:
+                {
+                    return *lhs.m_value.array == *rhs.m_value.array;
+                }
+                case value_t::object:
+                {
+                    return *lhs.m_value.object == *rhs.m_value.object;
+                }
+                case value_t::null:
+                {
+                    return true;
+                }
+                case value_t::string:
+                {
+                    return *lhs.m_value.string == *rhs.m_value.string;
+                }
+                case value_t::boolean:
+                {
+                    return lhs.m_value.boolean == rhs.m_value.boolean;
+                }
+                case value_t::number_integer:
+                {
+                    return lhs.m_value.number_integer == rhs.m_value.number_integer;
+                }
+                case value_t::number_unsigned:
+                {
+                    return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned;
+                }
+                case value_t::number_float:
+                {
+                    return lhs.m_value.number_float == rhs.m_value.number_float;
+                }
+                default:
+                {
+                    return false;
+                }
+            }
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        {
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        {
+            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer;
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned);
+        }
+
+        return false;
+    }
+
+    /*!
+    @brief comparison: equal
+
+    The functions compares the given JSON value against a null pointer. As the
+    null pointer can be used to initialize a JSON value to null, a comparison
+    of JSON value @a v with a null pointer should be equivalent to call
+    `v.is_null()`.
+
+    @param[in] v  JSON value to consider
+    @return whether @a v is null
+
+    @complexity Constant.
+
+    @liveexample{The example compares several JSON types to the null pointer.
+    ,operator__equal__nullptr_t}
+
+    @since version 1.0.0
+    */
+    friend bool operator==(const_reference v, std::nullptr_t) noexcept
+    {
+        return v.is_null();
+    }
+
+    /*!
+    @brief comparison: equal
+    @copydoc operator==(const_reference, std::nullptr_t)
+    */
+    friend bool operator==(std::nullptr_t, const_reference v) noexcept
+    {
+        return v.is_null();
+    }
+
+    /*!
+    @brief comparison: not equal
+
+    Compares two JSON values for inequality by calculating `not (lhs == rhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether the values @a lhs and @a rhs are not equal
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__notequal}
+
+    @since version 1.0.0
+    */
+    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs == rhs);
+    }
+
+    /*!
+    @brief comparison: not equal
+
+    The functions compares the given JSON value against a null pointer. As the
+    null pointer can be used to initialize a JSON value to null, a comparison
+    of JSON value @a v with a null pointer should be equivalent to call
+    `not v.is_null()`.
+
+    @param[in] v  JSON value to consider
+    @return whether @a v is not null
+
+    @complexity Constant.
+
+    @liveexample{The example compares several JSON types to the null pointer.
+    ,operator__notequal__nullptr_t}
+
+    @since version 1.0.0
+    */
+    friend bool operator!=(const_reference v, std::nullptr_t) noexcept
+    {
+        return not v.is_null();
+    }
+
+    /*!
+    @brief comparison: not equal
+    @copydoc operator!=(const_reference, std::nullptr_t)
+    */
+    friend bool operator!=(std::nullptr_t, const_reference v) noexcept
+    {
+        return not v.is_null();
+    }
+
+    /*!
+    @brief comparison: less than
+
+    Compares whether one JSON value @a lhs is less than another JSON value @a
+    rhs according to the following rules:
+    - If @a lhs and @a rhs have the same type, the values are compared using
+      the default `<` operator.
+    - Integer and floating-point numbers are automatically converted before
+      comparison
+    - In case @a lhs and @a rhs have different types, the values are ignored
+      and the order of the types is considered, see
+      @ref operator<(const value_t, const value_t).
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is less than @a rhs
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__less}
+
+    @since version 1.0.0
+    */
+    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
+    {
+        const auto lhs_type = lhs.type();
+        const auto rhs_type = rhs.type();
+
+        if (lhs_type == rhs_type)
+        {
+            switch (lhs_type)
+            {
+                case value_t::array:
+                {
+                    return *lhs.m_value.array < *rhs.m_value.array;
+                }
+                case value_t::object:
+                {
+                    return *lhs.m_value.object < *rhs.m_value.object;
+                }
+                case value_t::null:
+                {
+                    return false;
+                }
+                case value_t::string:
+                {
+                    return *lhs.m_value.string < *rhs.m_value.string;
+                }
+                case value_t::boolean:
+                {
+                    return lhs.m_value.boolean < rhs.m_value.boolean;
+                }
+                case value_t::number_integer:
+                {
+                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
+                }
+                case value_t::number_unsigned:
+                {
+                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
+                }
+                case value_t::number_float:
+                {
+                    return lhs.m_value.number_float < rhs.m_value.number_float;
+                }
+                default:
+                {
+                    return false;
+                }
+            }
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        {
+            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        {
+            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
+        }
+
+        // We only reach this line if we cannot compare values. In that case,
+        // we compare types. Note we have to call the operator explicitly,
+        // because MSVC has problems otherwise.
+        return operator<(lhs_type, rhs_type);
+    }
+
+    /*!
+    @brief comparison: less than or equal
+
+    Compares whether one JSON value @a lhs is less than or equal to another
+    JSON value by calculating `not (rhs < lhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is less than or equal to @a rhs
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__greater}
+
+    @since version 1.0.0
+    */
+    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (rhs < lhs);
+    }
+
+    /*!
+    @brief comparison: greater than
+
+    Compares whether one JSON value @a lhs is greater than another
+    JSON value by calculating `not (lhs <= rhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is greater than to @a rhs
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__lessequal}
+
+    @since version 1.0.0
+    */
+    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs <= rhs);
+    }
+
+    /*!
+    @brief comparison: greater than or equal
+
+    Compares whether one JSON value @a lhs is greater than or equal to another
+    JSON value by calculating `not (lhs < rhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is greater than or equal to @a rhs
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__greaterequal}
+
+    @since version 1.0.0
+    */
+    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs < rhs);
+    }
+
+    /// @}
+
+
+    ///////////////////
+    // serialization //
+    ///////////////////
+
+    /// @name serialization
+    /// @{
+
+    /*!
+    @brief serialize to stream
+
+    Serialize the given JSON value @a j to the output stream @a o. The JSON
+    value will be serialized using the @ref dump member function. The
+    indentation of the output can be controlled with the member variable
+    `width` of the output stream @a o. For instance, using the manipulator
+    `std::setw(4)` on @a o sets the indentation level to `4` and the
+    serialization result is the same as calling `dump(4)`.
+
+    @note During serializaion, the locale and the precision of the output
+    stream @a o are changed. The original values are restored when the
+    function returns.
+
+    @param[in,out] o  stream to serialize to
+    @param[in] j  JSON value to serialize
+
+    @return the stream @a o
+
+    @complexity Linear.
+
+    @liveexample{The example below shows the serialization with different
+    parameters to `width` to adjust the indentation level.,operator_serialize}
+
+    @since version 1.0.0
+    */
+    friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
+    {
+        // read width member and use it as indentation parameter if nonzero
+        const bool pretty_print = (o.width() > 0);
+        const auto indentation = (pretty_print ? o.width() : 0);
+
+        // reset width to 0 for subsequent calls to this stream
+        o.width(0);
+
+        // fix locale problems
+        const auto old_locale = o.imbue(std::locale(std::locale(), new DecimalSeparator));
+        // set precision
+
+        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
+        // string->float->string, string->double->string or string->long
+        // double->string; to be safe, we read this value from
+        // std::numeric_limits<number_float_t>::digits10
+        const auto old_precision = o.precision(std::numeric_limits<double>::digits10);
+
+        // do the actual serialization
+        j.dump(o, pretty_print, static_cast<unsigned int>(indentation));
+
+        // reset locale and precision
+        o.imbue(old_locale);
+        o.precision(old_precision);
+        return o;
+    }
+
+    /*!
+    @brief serialize to stream
+    @copydoc operator<<(std::ostream&, const basic_json&)
+    */
+    friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
+    {
+        return o << j;
+    }
+
+    /// @}
+
+
+    /////////////////////
+    // deserialization //
+    /////////////////////
+
+    /// @name deserialization
+    /// @{
+
+    /*!
+    @brief deserialize from string
+
+    @param[in] s  string to read a serialized JSON value from
+    @param[in] cb a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @return result of the deserialization
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates the `parse()` function with
+    and without callback function.,parse__string__parser_callback_t}
+
+    @sa @ref parse(std::istream&, const parser_callback_t) for a version that
+    reads from an input stream
+
+    @since version 1.0.0
+    */
+    static basic_json parse(const string_t& s,
+                            const parser_callback_t cb = nullptr)
+    {
+        return parser(s, cb).parse();
+    }
+
+    /*!
+    @brief deserialize from stream
+
+    @param[in,out] i  stream to read a serialized JSON value from
+    @param[in] cb a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @return result of the deserialization
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates the `parse()` function with
+    and without callback function.,parse__istream__parser_callback_t}
+
+    @sa @ref parse(const string_t&, const parser_callback_t) for a version
+    that reads from a string
+
+    @since version 1.0.0
+    */
+    static basic_json parse(std::istream& i,
+                            const parser_callback_t cb = nullptr)
+    {
+        return parser(i, cb).parse();
+    }
+
+    /*!
+    @copydoc parse(std::istream&, const parser_callback_t)
+    */
+    static basic_json parse(std::istream&& i,
+                            const parser_callback_t cb = nullptr)
+    {
+        return parser(i, cb).parse();
+    }
+
+    /*!
+    @brief deserialize from stream
+
+    Deserializes an input stream to a JSON value.
+
+    @param[in,out] i  input stream to read a serialized JSON value from
+    @param[in,out] j  JSON value to write the deserialized input to
+
+    @throw std::invalid_argument in case of parse errors
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below shows how a JSON value is constructed by
+    reading a serialization from a stream.,operator_deserialize}
+
+    @sa parse(std::istream&, const parser_callback_t) for a variant with a
+    parser callback function to filter values while parsing
+
+    @since version 1.0.0
+    */
+    friend std::istream& operator<<(basic_json& j, std::istream& i)
+    {
+        j = parser(i).parse();
+        return i;
+    }
+
+    /*!
+    @brief deserialize from stream
+    @copydoc operator<<(basic_json&, std::istream&)
+    */
+    friend std::istream& operator>>(std::istream& i, basic_json& j)
+    {
+        j = parser(i).parse();
+        return i;
+    }
+
+    /// @}
+
+
+  private:
+    ///////////////////////////
+    // convenience functions //
+    ///////////////////////////
+
+    /*!
+    @brief return the type as string
+
+    Returns the type name as string to be used in error messages - usually to
+    indicate that a function was called on a wrong JSON type.
+
+    @return basically a string representation of a the @ref m_type member
+
+    @complexity Constant.
+
+    @since version 1.0.0
+    */
+    std::string type_name() const
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+                return "null";
+            case value_t::object:
+                return "object";
+            case value_t::array:
+                return "array";
+            case value_t::string:
+                return "string";
+            case value_t::boolean:
+                return "boolean";
+            case value_t::discarded:
+                return "discarded";
+            default:
+                return "number";
+        }
+    }
+
+    /*!
+    @brief calculates the extra space to escape a JSON string
+
+    @param[in] s  the string to escape
+    @return the number of characters required to escape string @a s
+
+    @complexity Linear in the length of string @a s.
+    */
+    static std::size_t extra_space(const string_t& s) noexcept
+    {
+        return std::accumulate(s.begin(), s.end(), size_t{},
+                               [](size_t res, typename string_t::value_type c)
+        {
+            switch (c)
+            {
+                case '"':
+                case '\\':
+                case '\b':
+                case '\f':
+                case '\n':
+                case '\r':
+                case '\t':
+                {
+                    // from c (1 byte) to \x (2 bytes)
+                    return res + 1;
+                }
+
+                default:
+                {
+                    if (c >= 0x00 and c <= 0x1f)
+                    {
+                        // from c (1 byte) to \uxxxx (6 bytes)
+                        return res + 5;
+                    }
+                    else
+                    {
+                        return res;
+                    }
+                }
+            }
+        });
+    }
+
+    /*!
+    @brief escape a string
+
+    Escape a string by replacing certain special characters by a sequence of
+    an escape character (backslash) and another character and other control
+    characters by a sequence of "\u" followed by a four-digit hex
+    representation.
+
+    @param[in] s  the string to escape
+    @return  the escaped string
+
+    @complexity Linear in the length of string @a s.
+    */
+    static string_t escape_string(const string_t& s)
+    {
+        const auto space = extra_space(s);
+        if (space == 0)
+        {
+            return s;
+        }
+
+        // create a result string of necessary size
+        string_t result(s.size() + space, '\\');
+        std::size_t pos = 0;
+
+        for (const auto& c : s)
+        {
+            switch (c)
+            {
+                // quotation mark (0x22)
+                case '"':
+                {
+                    result[pos + 1] = '"';
+                    pos += 2;
+                    break;
+                }
+
+                // reverse solidus (0x5c)
+                case '\\':
+                {
+                    // nothing to change
+                    pos += 2;
+                    break;
+                }
+
+                // backspace (0x08)
+                case '\b':
+                {
+                    result[pos + 1] = 'b';
+                    pos += 2;
+                    break;
+                }
+
+                // formfeed (0x0c)
+                case '\f':
+                {
+                    result[pos + 1] = 'f';
+                    pos += 2;
+                    break;
+                }
+
+                // newline (0x0a)
+                case '\n':
+                {
+                    result[pos + 1] = 'n';
+                    pos += 2;
+                    break;
+                }
+
+                // carriage return (0x0d)
+                case '\r':
+                {
+                    result[pos + 1] = 'r';
+                    pos += 2;
+                    break;
+                }
+
+                // horizontal tab (0x09)
+                case '\t':
+                {
+                    result[pos + 1] = 't';
+                    pos += 2;
+                    break;
+                }
+
+                default:
+                {
+                    if (c >= 0x00 and c <= 0x1f)
+                    {
+                        // convert a number 0..15 to its hex representation
+                        // (0..f)
+                        static const char hexify[16] =
+                        {
+                            '0', '1', '2', '3', '4', '5', '6', '7',
+                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
+                        };
+
+                        // print character c as \uxxxx
+                        for (const char m :
+                    { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f]
+                        })
+                        {
+                            result[++pos] = m;
+                        }
+
+                        ++pos;
+                    }
+                    else
+                    {
+                        // all other characters are added as-is
+                        result[pos++] = c;
+                    }
+                    break;
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief internal implementation of the serialization function
+
+    This function is called by the public member function dump and organizes
+    the serialization internally. The indentation level is propagated as
+    additional parameter. In case of arrays and objects, the function is
+    called recursively. Note that
+
+    - strings and object keys are escaped using `escape_string()`
+    - integer numbers are converted implicitly via `operator<<`
+    - floating-point numbers are converted to a string using `"%g"` format
+
+    @param[out] o              stream to write to
+    @param[in] pretty_print    whether the output shall be pretty-printed
+    @param[in] indent_step     the indent level
+    @param[in] current_indent  the current indent level (only used internally)
+    */
+    void dump(std::ostream& o,
+              const bool pretty_print,
+              const unsigned int indent_step,
+              const unsigned int current_indent = 0) const
+    {
+        // variable to hold indentation for recursive calls
+        unsigned int new_indent = current_indent;
+
+        switch (m_type)
+        {
+            case value_t::object:
+            {
+                if (m_value.object->empty())
+                {
+                    o << "{}";
+                    return;
+                }
+
+                o << "{";
+
+                // increase indentation
+                if (pretty_print)
+                {
+                    new_indent += indent_step;
+                    o << "\n";
+                }
+
+                for (auto i = m_value.object->cbegin(); i != m_value.object->cend(); ++i)
+                {
+                    if (i != m_value.object->cbegin())
+                    {
+                        o << (pretty_print ? ",\n" : ",");
+                    }
+                    o << string_t(new_indent, ' ') << "\""
+                      << escape_string(i->first) << "\":"
+                      << (pretty_print ? " " : "");
+                    i->second.dump(o, pretty_print, indent_step, new_indent);
+                }
+
+                // decrease indentation
+                if (pretty_print)
+                {
+                    new_indent -= indent_step;
+                    o << "\n";
+                }
+
+                o << string_t(new_indent, ' ') + "}";
+                return;
+            }
+
+            case value_t::array:
+            {
+                if (m_value.array->empty())
+                {
+                    o << "[]";
+                    return;
+                }
+
+                o << "[";
+
+                // increase indentation
+                if (pretty_print)
+                {
+                    new_indent += indent_step;
+                    o << "\n";
+                }
+
+                for (auto i = m_value.array->cbegin(); i != m_value.array->cend(); ++i)
+                {
+                    if (i != m_value.array->cbegin())
+                    {
+                        o << (pretty_print ? ",\n" : ",");
+                    }
+                    o << string_t(new_indent, ' ');
+                    i->dump(o, pretty_print, indent_step, new_indent);
+                }
+
+                // decrease indentation
+                if (pretty_print)
+                {
+                    new_indent -= indent_step;
+                    o << "\n";
+                }
+
+                o << string_t(new_indent, ' ') << "]";
+                return;
+            }
+
+            case value_t::string:
+            {
+                o << string_t("\"") << escape_string(*m_value.string) << "\"";
+                return;
+            }
+
+            case value_t::boolean:
+            {
+                o << (m_value.boolean ? "true" : "false");
+                return;
+            }
+
+            case value_t::number_integer:
+            {
+                o << m_value.number_integer;
+                return;
+            }
+
+            case value_t::number_unsigned:
+            {
+                o << m_value.number_unsigned;
+                return;
+            }
+
+            case value_t::number_float:
+            {
+                if (m_value.number_float == 0)
+                {
+                    // special case for zero to get "0.0"/"-0.0"
+                    o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
+                }
+                else
+                {
+                    o << m_value.number_float;
+                }
+                return;
+            }
+
+            case value_t::discarded:
+            {
+                o << "<discarded>";
+                return;
+            }
+
+            case value_t::null:
+            {
+                o << "null";
+                return;
+            }
+        }
+    }
+
+  private:
+    //////////////////////
+    // member variables //
+    //////////////////////
+
+    /// the type of the current element
+    value_t m_type = value_t::null;
+
+    /// the value of the current element
+    json_value m_value = {};
+
+
+  private:
+    ///////////////
+    // iterators //
+    ///////////////
+
+    /*!
+    @brief an iterator for primitive JSON types
+
+    This class models an iterator for primitive JSON types (boolean, number,
+    string). It's only purpose is to allow the iterator/const_iterator classes
+    to "iterate" over primitive values. Internally, the iterator is modeled by
+    a `difference_type` variable. Value begin_value (`0`) models the begin,
+    end_value (`1`) models past the end.
+    */
+    class primitive_iterator_t
+    {
+      public:
+        /// set iterator to a defined beginning
+        void set_begin() noexcept
+        {
+            m_it = begin_value;
+        }
+
+        /// set iterator to a defined past the end
+        void set_end() noexcept
+        {
+            m_it = end_value;
+        }
+
+        /// return whether the iterator can be dereferenced
+        constexpr bool is_begin() const noexcept
+        {
+            return (m_it == begin_value);
+        }
+
+        /// return whether the iterator is at end
+        constexpr bool is_end() const noexcept
+        {
+            return (m_it == end_value);
+        }
+
+        /// return reference to the value to change and compare
+        operator difference_type& () noexcept
+        {
+            return m_it;
+        }
+
+        /// return value to compare
+        constexpr operator difference_type () const noexcept
+        {
+            return m_it;
+        }
+
+      private:
+        static constexpr difference_type begin_value = 0;
+        static constexpr difference_type end_value = begin_value + 1;
+
+        /// iterator as signed integer type
+        difference_type m_it = std::numeric_limits<std::ptrdiff_t>::denorm_min();
+    };
+
+    /*!
+    @brief an iterator value
+
+    @note This structure could easily be a union, but MSVC currently does not
+    allow unions members with complex constructors, see
+    https://github.com/nlohmann/json/pull/105.
+    */
+    struct internal_iterator
+    {
+        /// iterator for JSON objects
+        typename object_t::iterator object_iterator;
+        /// iterator for JSON arrays
+        typename array_t::iterator array_iterator;
+        /// generic iterator for all other types
+        primitive_iterator_t primitive_iterator;
+
+        /// create an uninitialized internal_iterator
+        internal_iterator() noexcept
+            : object_iterator(), array_iterator(), primitive_iterator()
+        {}
+    };
+
+    /// proxy class for the iterator_wrapper functions
+    template<typename IteratorType>
+    class iteration_proxy
+    {
+      private:
+        /// helper class for iteration
+        class iteration_proxy_internal
+        {
+          private:
+            /// the iterator
+            IteratorType anchor;
+            /// an index for arrays (used to create key names)
+            size_t array_index = 0;
+
+          public:
+            explicit iteration_proxy_internal(IteratorType it) noexcept
+                : anchor(it)
+            {}
+
+            /// dereference operator (needed for range-based for)
+            iteration_proxy_internal& operator*()
+            {
+                return *this;
+            }
+
+            /// increment operator (needed for range-based for)
+            iteration_proxy_internal& operator++()
+            {
+                ++anchor;
+                ++array_index;
+
+                return *this;
+            }
+
+            /// inequality operator (needed for range-based for)
+            bool operator!= (const iteration_proxy_internal& o) const
+            {
+                return anchor != o.anchor;
+            }
+
+            /// return key of the iterator
+            typename basic_json::string_t key() const
+            {
+                assert(anchor.m_object != nullptr);
+
+                switch (anchor.m_object->type())
+                {
+                    // use integer array index as key
+                    case value_t::array:
+                    {
+                        return std::to_string(array_index);
+                    }
+
+                    // use key from the object
+                    case value_t::object:
+                    {
+                        return anchor.key();
+                    }
+
+                    // use an empty key for all primitive types
+                    default:
+                    {
+                        return "";
+                    }
+                }
+            }
+
+            /// return value of the iterator
+            typename IteratorType::reference value() const
+            {
+                return anchor.value();
+            }
+        };
+
+        /// the container to iterate
+        typename IteratorType::reference container;
+
+      public:
+        /// construct iteration proxy from a container
+        explicit iteration_proxy(typename IteratorType::reference cont)
+            : container(cont)
+        {}
+
+        /// return iterator begin (needed for range-based for)
+        iteration_proxy_internal begin() noexcept
+        {
+            return iteration_proxy_internal(container.begin());
+        }
+
+        /// return iterator end (needed for range-based for)
+        iteration_proxy_internal end() noexcept
+        {
+            return iteration_proxy_internal(container.end());
+        }
+    };
+
+  public:
+    /*!
+    @brief a const random access iterator for the @ref basic_json class
+
+    This class implements a const iterator for the @ref basic_json class. From
+    this class, the @ref iterator class is derived.
+
+    @note An iterator is called *initialized* when a pointer to a JSON value
+          has been set (e.g., by a constructor or a copy assignment). If the
+          iterator is default-constructed, it is *uninitialized* and most
+          methods are undefined. The library uses assertions to detect calls
+          on uninitialized iterators.
+
+    @requirement The class satisfies the following concept requirements:
+    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
+      The iterator that can be moved to point (forward and backward) to any
+      element in constant time.
+
+    @since version 1.0.0
+    */
+    class const_iterator : public std::iterator<std::random_access_iterator_tag, const basic_json>
+    {
+        /// allow basic_json to access private members
+        friend class basic_json;
+
+      public:
+        /// the type of the values when the iterator is dereferenced
+        using value_type = typename basic_json::value_type;
+        /// a type to represent differences between iterators
+        using difference_type = typename basic_json::difference_type;
+        /// defines a pointer to the type iterated over (value_type)
+        using pointer = typename basic_json::const_pointer;
+        /// defines a reference to the type iterated over (value_type)
+        using reference = typename basic_json::const_reference;
+        /// the category of the iterator
+        using iterator_category = std::bidirectional_iterator_tag;
+
+        /// default constructor
+        const_iterator() = default;
+
+        /*!
+        @brief constructor for a given JSON instance
+        @param[in] object  pointer to a JSON object for this iterator
+        @pre object != nullptr
+        @post The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        explicit const_iterator(pointer object) noexcept
+            : m_object(object)
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    m_it.object_iterator = typename object_t::iterator();
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    m_it.array_iterator = typename array_t::iterator();
+                    break;
+                }
+
+                default:
+                {
+                    m_it.primitive_iterator = primitive_iterator_t();
+                    break;
+                }
+            }
+        }
+
+        /*!
+        @brief copy constructor given a non-const iterator
+        @param[in] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
+        explicit const_iterator(const iterator& other) noexcept
+            : m_object(other.m_object)
+        {
+            if (m_object != nullptr)
+            {
+                switch (m_object->m_type)
+                {
+                    case basic_json::value_t::object:
+                    {
+                        m_it.object_iterator = other.m_it.object_iterator;
+                        break;
+                    }
+
+                    case basic_json::value_t::array:
+                    {
+                        m_it.array_iterator = other.m_it.array_iterator;
+                        break;
+                    }
+
+                    default:
+                    {
+                        m_it.primitive_iterator = other.m_it.primitive_iterator;
+                        break;
+                    }
+                }
+            }
+        }
+
+        /*!
+        @brief copy constructor
+        @param[in] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
+        const_iterator(const const_iterator& other) noexcept
+            : m_object(other.m_object), m_it(other.m_it)
+        {}
+
+        /*!
+        @brief copy assignment
+        @param[in,out] other  iterator to copy from
+        @note It is not checked whether @a other is initialized.
+        */
+        const_iterator& operator=(const_iterator other) noexcept(
+            std::is_nothrow_move_constructible<pointer>::value and
+            std::is_nothrow_move_assignable<pointer>::value and
+            std::is_nothrow_move_constructible<internal_iterator>::value and
+            std::is_nothrow_move_assignable<internal_iterator>::value
+        )
+        {
+            std::swap(m_object, other.m_object);
+            std::swap(m_it, other.m_it);
+            return *this;
+        }
+
+      private:
+        /*!
+        @brief set the iterator to the first value
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        void set_begin() noexcept
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    m_it.object_iterator = m_object->m_value.object->begin();
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    m_it.array_iterator = m_object->m_value.array->begin();
+                    break;
+                }
+
+                case basic_json::value_t::null:
+                {
+                    // set to end so begin()==end() is true: null is empty
+                    m_it.primitive_iterator.set_end();
+                    break;
+                }
+
+                default:
+                {
+                    m_it.primitive_iterator.set_begin();
+                    break;
+                }
+            }
+        }
+
+        /*!
+        @brief set the iterator past the last value
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        void set_end() noexcept
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    m_it.object_iterator = m_object->m_value.object->end();
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    m_it.array_iterator = m_object->m_value.array->end();
+                    break;
+                }
+
+                default:
+                {
+                    m_it.primitive_iterator.set_end();
+                    break;
+                }
+            }
+        }
+
+      public:
+        /*!
+        @brief return a reference to the value pointed to by the iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        reference operator*() const
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    assert(m_it.object_iterator != m_object->m_value.object->end());
+                    return m_it.object_iterator->second;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    assert(m_it.array_iterator != m_object->m_value.array->end());
+                    return *m_it.array_iterator;
+                }
+
+                case basic_json::value_t::null:
+                {
+                    throw std::out_of_range("cannot get value");
+                }
+
+                default:
+                {
+                    if (m_it.primitive_iterator.is_begin())
+                    {
+                        return *m_object;
+                    }
+                    else
+                    {
+                        throw std::out_of_range("cannot get value");
+                    }
+                }
+            }
+        }
+
+        /*!
+        @brief dereference the iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        pointer operator->() const
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    assert(m_it.object_iterator != m_object->m_value.object->end());
+                    return &(m_it.object_iterator->second);
+                }
+
+                case basic_json::value_t::array:
+                {
+                    assert(m_it.array_iterator != m_object->m_value.array->end());
+                    return &*m_it.array_iterator;
+                }
+
+                default:
+                {
+                    if (m_it.primitive_iterator.is_begin())
+                    {
+                        return m_object;
+                    }
+                    else
+                    {
+                        throw std::out_of_range("cannot get value");
+                    }
+                }
+            }
+        }
+
+        /*!
+        @brief post-increment (it++)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator operator++(int)
+        {
+            auto result = *this;
+            ++(*this);
+            return result;
+        }
+
+        /*!
+        @brief pre-increment (++it)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator& operator++()
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    std::advance(m_it.object_iterator, 1);
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    std::advance(m_it.array_iterator, 1);
+                    break;
+                }
+
+                default:
+                {
+                    ++m_it.primitive_iterator;
+                    break;
+                }
+            }
+
+            return *this;
+        }
+
+        /*!
+        @brief post-decrement (it--)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator operator--(int)
+        {
+            auto result = *this;
+            --(*this);
+            return result;
+        }
+
+        /*!
+        @brief pre-decrement (--it)
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator& operator--()
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    std::advance(m_it.object_iterator, -1);
+                    break;
+                }
+
+                case basic_json::value_t::array:
+                {
+                    std::advance(m_it.array_iterator, -1);
+                    break;
+                }
+
+                default:
+                {
+                    --m_it.primitive_iterator;
+                    break;
+                }
+            }
+
+            return *this;
+        }
+
+        /*!
+        @brief  comparison: equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator==(const const_iterator& other) const
+        {
+            // if objects are not the same, the comparison is undefined
+            if (m_object != other.m_object)
+            {
+                throw std::domain_error("cannot compare iterators of different containers");
+            }
+
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    return (m_it.object_iterator == other.m_it.object_iterator);
+                }
+
+                case basic_json::value_t::array:
+                {
+                    return (m_it.array_iterator == other.m_it.array_iterator);
+                }
+
+                default:
+                {
+                    return (m_it.primitive_iterator == other.m_it.primitive_iterator);
+                }
+            }
+        }
+
+        /*!
+        @brief  comparison: not equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator!=(const const_iterator& other) const
+        {
+            return not operator==(other);
+        }
+
+        /*!
+        @brief  comparison: smaller
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator<(const const_iterator& other) const
+        {
+            // if objects are not the same, the comparison is undefined
+            if (m_object != other.m_object)
+            {
+                throw std::domain_error("cannot compare iterators of different containers");
+            }
+
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    throw std::domain_error("cannot compare order of object iterators");
+                }
+
+                case basic_json::value_t::array:
+                {
+                    return (m_it.array_iterator < other.m_it.array_iterator);
+                }
+
+                default:
+                {
+                    return (m_it.primitive_iterator < other.m_it.primitive_iterator);
+                }
+            }
+        }
+
+        /*!
+        @brief  comparison: less than or equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator<=(const const_iterator& other) const
+        {
+            return not other.operator < (*this);
+        }
+
+        /*!
+        @brief  comparison: greater than
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator>(const const_iterator& other) const
+        {
+            return not operator<=(other);
+        }
+
+        /*!
+        @brief  comparison: greater than or equal
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        bool operator>=(const const_iterator& other) const
+        {
+            return not operator<(other);
+        }
+
+        /*!
+        @brief  add to iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator& operator+=(difference_type i)
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    throw std::domain_error("cannot use offsets with object iterators");
+                }
+
+                case basic_json::value_t::array:
+                {
+                    std::advance(m_it.array_iterator, i);
+                    break;
+                }
+
+                default:
+                {
+                    m_it.primitive_iterator += i;
+                    break;
+                }
+            }
+
+            return *this;
+        }
+
+        /*!
+        @brief  subtract from iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator& operator-=(difference_type i)
+        {
+            return operator+=(-i);
+        }
+
+        /*!
+        @brief  add to iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator operator+(difference_type i)
+        {
+            auto result = *this;
+            result += i;
+            return result;
+        }
+
+        /*!
+        @brief  subtract from iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        const_iterator operator-(difference_type i)
+        {
+            auto result = *this;
+            result -= i;
+            return result;
+        }
+
+        /*!
+        @brief  return difference
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        difference_type operator-(const const_iterator& other) const
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    throw std::domain_error("cannot use offsets with object iterators");
+                }
+
+                case basic_json::value_t::array:
+                {
+                    return m_it.array_iterator - other.m_it.array_iterator;
+                }
+
+                default:
+                {
+                    return m_it.primitive_iterator - other.m_it.primitive_iterator;
+                }
+            }
+        }
+
+        /*!
+        @brief  access to successor
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        reference operator[](difference_type n) const
+        {
+            assert(m_object != nullptr);
+
+            switch (m_object->m_type)
+            {
+                case basic_json::value_t::object:
+                {
+                    throw std::domain_error("cannot use operator[] for object iterators");
+                }
+
+                case basic_json::value_t::array:
+                {
+                    return *std::next(m_it.array_iterator, n);
+                }
+
+                case basic_json::value_t::null:
+                {
+                    throw std::out_of_range("cannot get value");
+                }
+
+                default:
+                {
+                    if (m_it.primitive_iterator == -n)
+                    {
+                        return *m_object;
+                    }
+                    else
+                    {
+                        throw std::out_of_range("cannot get value");
+                    }
+                }
+            }
+        }
+
+        /*!
+        @brief  return the key of an object iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        typename object_t::key_type key() const
+        {
+            assert(m_object != nullptr);
+
+            if (m_object->is_object())
+            {
+                return m_it.object_iterator->first;
+            }
+            else
+            {
+                throw std::domain_error("cannot use key() for non-object iterators");
+            }
+        }
+
+        /*!
+        @brief  return the value of an iterator
+        @pre The iterator is initialized; i.e. `m_object != nullptr`.
+        */
+        reference value() const
+        {
+            return operator*();
+        }
+
+      private:
+        /// associated JSON instance
+        pointer m_object = nullptr;
+        /// the actual iterator of the associated instance
+        internal_iterator m_it = internal_iterator();
+    };
+
+    /*!
+    @brief a mutable random access iterator for the @ref basic_json class
+
+    @requirement The class satisfies the following concept requirements:
+    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
+      The iterator that can be moved to point (forward and backward) to any
+      element in constant time.
+    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
+      It is possible to write to the pointed-to element.
+
+    @since version 1.0.0
+    */
+    class iterator : public const_iterator
+    {
+      public:
+        using base_iterator = const_iterator;
+        using pointer = typename basic_json::pointer;
+        using reference = typename basic_json::reference;
+
+        /// default constructor
+        iterator() = default;
+
+        /// constructor for a given JSON instance
+        explicit iterator(pointer object) noexcept
+            : base_iterator(object)
+        {}
+
+        /// copy constructor
+        iterator(const iterator& other) noexcept
+            : base_iterator(other)
+        {}
+
+        /// copy assignment
+        iterator& operator=(iterator other) noexcept(
+            std::is_nothrow_move_constructible<pointer>::value and
+            std::is_nothrow_move_assignable<pointer>::value and
+            std::is_nothrow_move_constructible<internal_iterator>::value and
+            std::is_nothrow_move_assignable<internal_iterator>::value
+        )
+        {
+            base_iterator::operator=(other);
+            return *this;
+        }
+
+        /// return a reference to the value pointed to by the iterator
+        reference operator*() const
+        {
+            return const_cast<reference>(base_iterator::operator*());
+        }
+
+        /// dereference the iterator
+        pointer operator->() const
+        {
+            return const_cast<pointer>(base_iterator::operator->());
+        }
+
+        /// post-increment (it++)
+        iterator operator++(int)
+        {
+            iterator result = *this;
+            base_iterator::operator++();
+            return result;
+        }
+
+        /// pre-increment (++it)
+        iterator& operator++()
+        {
+            base_iterator::operator++();
+            return *this;
+        }
+
+        /// post-decrement (it--)
+        iterator operator--(int)
+        {
+            iterator result = *this;
+            base_iterator::operator--();
+            return result;
+        }
+
+        /// pre-decrement (--it)
+        iterator& operator--()
+        {
+            base_iterator::operator--();
+            return *this;
+        }
+
+        /// add to iterator
+        iterator& operator+=(difference_type i)
+        {
+            base_iterator::operator+=(i);
+            return *this;
+        }
+
+        /// subtract from iterator
+        iterator& operator-=(difference_type i)
+        {
+            base_iterator::operator-=(i);
+            return *this;
+        }
+
+        /// add to iterator
+        iterator operator+(difference_type i)
+        {
+            auto result = *this;
+            result += i;
+            return result;
+        }
+
+        /// subtract from iterator
+        iterator operator-(difference_type i)
+        {
+            auto result = *this;
+            result -= i;
+            return result;
+        }
+
+        /// return difference
+        difference_type operator-(const iterator& other) const
+        {
+            return base_iterator::operator-(other);
+        }
+
+        /// access to successor
+        reference operator[](difference_type n) const
+        {
+            return const_cast<reference>(base_iterator::operator[](n));
+        }
+
+        /// return the value of an iterator
+        reference value() const
+        {
+            return const_cast<reference>(base_iterator::value());
+        }
+    };
+
+    /*!
+    @brief a template for a reverse iterator class
+
+    @tparam Base the base iterator type to reverse. Valid types are @ref
+    iterator (to create @ref reverse_iterator) and @ref const_iterator (to
+    create @ref const_reverse_iterator).
+
+    @requirement The class satisfies the following concept requirements:
+    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
+      The iterator that can be moved to point (forward and backward) to any
+      element in constant time.
+    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
+      It is possible to write to the pointed-to element (only if @a Base is
+      @ref iterator).
+
+    @since version 1.0.0
+    */
+    template<typename Base>
+    class json_reverse_iterator : public std::reverse_iterator<Base>
+    {
+      public:
+        /// shortcut to the reverse iterator adaptor
+        using base_iterator = std::reverse_iterator<Base>;
+        /// the reference type for the pointed-to element
+        using reference = typename Base::reference;
+
+        /// create reverse iterator from iterator
+        json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept
+            : base_iterator(it)
+        {}
+
+        /// create reverse iterator from base class
+        json_reverse_iterator(const base_iterator& it) noexcept
+            : base_iterator(it)
+        {}
+
+        /// post-increment (it++)
+        json_reverse_iterator operator++(int)
+        {
+            return base_iterator::operator++(1);
+        }
+
+        /// pre-increment (++it)
+        json_reverse_iterator& operator++()
+        {
+            base_iterator::operator++();
+            return *this;
+        }
+
+        /// post-decrement (it--)
+        json_reverse_iterator operator--(int)
+        {
+            return base_iterator::operator--(1);
+        }
+
+        /// pre-decrement (--it)
+        json_reverse_iterator& operator--()
+        {
+            base_iterator::operator--();
+            return *this;
+        }
+
+        /// add to iterator
+        json_reverse_iterator& operator+=(difference_type i)
+        {
+            base_iterator::operator+=(i);
+            return *this;
+        }
+
+        /// add to iterator
+        json_reverse_iterator operator+(difference_type i) const
+        {
+            auto result = *this;
+            result += i;
+            return result;
+        }
+
+        /// subtract from iterator
+        json_reverse_iterator operator-(difference_type i) const
+        {
+            auto result = *this;
+            result -= i;
+            return result;
+        }
+
+        /// return difference
+        difference_type operator-(const json_reverse_iterator& other) const
+        {
+            return this->base() - other.base();
+        }
+
+        /// access to successor
+        reference operator[](difference_type n) const
+        {
+            return *(this->operator+(n));
+        }
+
+        /// return the key of an object iterator
+        typename object_t::key_type key() const
+        {
+            auto it = --this->base();
+            return it.key();
+        }
+
+        /// return the value of an iterator
+        reference value() const
+        {
+            auto it = --this->base();
+            return it.operator * ();
+        }
+    };
+
+
+  private:
+    //////////////////////
+    // lexer and parser //
+    //////////////////////
+
+    /*!
+    @brief lexical analysis
+
+    This class organizes the lexical analysis during JSON deserialization. The
+    core of it is a scanner generated by [re2c](http://re2c.org) that
+    processes a buffer and recognizes tokens according to RFC 7159.
+    */
+    class lexer
+    {
+      public:
+        /// token types for the parser
+        enum class token_type
+        {
+            uninitialized,   ///< indicating the scanner is uninitialized
+            literal_true,    ///< the `true` literal
+            literal_false,   ///< the `false` literal
+            literal_null,    ///< the `null` literal
+            value_string,    ///< a string -- use get_string() for actual value
+            value_number,    ///< a number -- use get_number() for actual value
+            begin_array,     ///< the character for array begin `[`
+            begin_object,    ///< the character for object begin `{`
+            end_array,       ///< the character for array end `]`
+            end_object,      ///< the character for object end `}`
+            name_separator,  ///< the name separator `:`
+            value_separator, ///< the value separator `,`
+            parse_error,     ///< indicating a parse error
+            end_of_input     ///< indicating the end of the input buffer
+        };
+
+        /// the char type to use in the lexer
+        using lexer_char_t = unsigned char;
+
+        /// constructor with a given buffer
+        explicit lexer(const string_t& s) noexcept
+            : m_stream(nullptr), m_buffer(s)
+        {
+            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
+            assert(m_content != nullptr);
+            m_start = m_cursor = m_content;
+            m_limit = m_content + s.size();
+        }
+
+        /// constructor with a given stream
+        explicit lexer(std::istream* s) noexcept
+            : m_stream(s), m_buffer()
+        {
+            assert(m_stream != nullptr);
+            std::getline(*m_stream, m_buffer);
+            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
+            assert(m_content != nullptr);
+            m_start = m_cursor = m_content;
+            m_limit = m_content + m_buffer.size();
+        }
+
+        /// default constructor
+        lexer() = default;
+
+        // switch off unwanted functions
+        lexer(const lexer&) = delete;
+        lexer operator=(const lexer&) = delete;
+
+        /*!
+        @brief create a string from one or two Unicode code points
+
+        There are two cases: (1) @a codepoint1 is in the Basic Multilingual
+        Plane (U+0000 through U+FFFF) and @a codepoint2 is 0, or (2)
+        @a codepoint1 and @a codepoint2 are a UTF-16 surrogate pair to
+        represent a code point above U+FFFF.
+
+        @param[in] codepoint1  the code point (can be high surrogate)
+        @param[in] codepoint2  the code point (can be low surrogate or 0)
+
+        @return string representation of the code point; the length of the
+        result string is between 1 and 4 characters.
+
+        @throw std::out_of_range if code point is > 0x10ffff; example: `"code
+        points above 0x10FFFF are invalid"`
+        @throw std::invalid_argument if the low surrogate is invalid; example:
+        `""missing or wrong low surrogate""`
+
+        @complexity Constant.
+
+        @see <http://en.wikipedia.org/wiki/UTF-8#Sample_code>
+        */
+        static string_t to_unicode(const std::size_t codepoint1,
+                                   const std::size_t codepoint2 = 0)
+        {
+            // calculate the code point from the given code points
+            std::size_t codepoint = codepoint1;
+
+            // check if codepoint1 is a high surrogate
+            if (codepoint1 >= 0xD800 and codepoint1 <= 0xDBFF)
+            {
+                // check if codepoint2 is a low surrogate
+                if (codepoint2 >= 0xDC00 and codepoint2 <= 0xDFFF)
+                {
+                    codepoint =
+                        // high surrogate occupies the most significant 22 bits
+                        (codepoint1 << 10)
+                        // low surrogate occupies the least significant 15 bits
+                        + codepoint2
+                        // there is still the 0xD800, 0xDC00 and 0x10000 noise
+                        // in the result so we have to subtract with:
+                        // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
+                        - 0x35FDC00;
+                }
+                else
+                {
+                    throw std::invalid_argument("missing or wrong low surrogate");
+                }
+            }
+
+            string_t result;
+
+            if (codepoint < 0x80)
+            {
+                // 1-byte characters: 0xxxxxxx (ASCII)
+                result.append(1, static_cast<typename string_t::value_type>(codepoint));
+            }
+            else if (codepoint <= 0x7ff)
+            {
+                // 2-byte characters: 110xxxxx 10xxxxxx
+                result.append(1, static_cast<typename string_t::value_type>(0xC0 | ((codepoint >> 6) & 0x1F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
+            }
+            else if (codepoint <= 0xffff)
+            {
+                // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
+                result.append(1, static_cast<typename string_t::value_type>(0xE0 | ((codepoint >> 12) & 0x0F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
+            }
+            else if (codepoint <= 0x10ffff)
+            {
+                // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+                result.append(1, static_cast<typename string_t::value_type>(0xF0 | ((codepoint >> 18) & 0x07)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 12) & 0x3F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
+                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
+            }
+            else
+            {
+                throw std::out_of_range("code points above 0x10FFFF are invalid");
+            }
+
+            return result;
+        }
+
+        /// return name of values of type token_type (only used for errors)
+        static std::string token_type_name(const token_type t)
+        {
+            switch (t)
+            {
+                case token_type::uninitialized:
+                    return "<uninitialized>";
+                case token_type::literal_true:
+                    return "true literal";
+                case token_type::literal_false:
+                    return "false literal";
+                case token_type::literal_null:
+                    return "null literal";
+                case token_type::value_string:
+                    return "string literal";
+                case token_type::value_number:
+                    return "number literal";
+                case token_type::begin_array:
+                    return "'['";
+                case token_type::begin_object:
+                    return "'{'";
+                case token_type::end_array:
+                    return "']'";
+                case token_type::end_object:
+                    return "'}'";
+                case token_type::name_separator:
+                    return "':'";
+                case token_type::value_separator:
+                    return "','";
+                case token_type::parse_error:
+                    return "<parse error>";
+                case token_type::end_of_input:
+                    return "end of input";
+                default:
+                {
+                    // catch non-enum values
+                    return "unknown token"; // LCOV_EXCL_LINE
+                }
+            }
+        }
+
+        /*!
+        This function implements a scanner for JSON. It is specified using
+        regular expressions that try to follow RFC 7159 as close as possible.
+        These regular expressions are then translated into a minimized
+        deterministic finite automaton (DFA) by the tool
+        [re2c](http://re2c.org). As a result, the translated code for this
+        function consists of a large block of code with `goto` jumps.
+
+        @return the class of the next token read from the buffer
+
+        @complexity Linear in the length of the input.\n
+
+        Proposition: The loop below will always terminate for finite input.\n
+
+        Proof (by contradiction): Assume a finite input. To loop forever, the
+        loop must never hit code with a `break` statement. The only code
+        snippets without a `break` statement are the continue statements for
+        whitespace and byte-order-marks. To loop forever, the input must be an
+        infinite sequence of whitespace or byte-order-marks. This contradicts
+        the assumption of finite input, q.e.d.
+        */
+        token_type scan() noexcept
+        {
+            while (true)
+            {
+                // pointer for backtracking information
+                m_marker = nullptr;
+
+                // remember the begin of the token
+                m_start = m_cursor;
+                assert(m_start != nullptr);
+
+
+                {
+                    lexer_char_t yych;
+                    unsigned int yyaccept = 0;
+                    static const unsigned char yybm[] =
+                    {
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,  32,  32,   0,   0,  32,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        160, 128,   0, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        192, 192, 192, 192, 192, 192, 192, 192,
+                        192, 192, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128,   0, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                        128, 128, 128, 128, 128, 128, 128, 128,
+                    };
+                    if ((m_limit - m_cursor) < 5)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 32)
+                    {
+                        goto basic_json_parser_6;
+                    }
+                    if (yych <= '\\')
+                    {
+                        if (yych <= '-')
+                        {
+                            if (yych <= '"')
+                            {
+                                if (yych <= 0x00)
+                                {
+                                    goto basic_json_parser_2;
+                                }
+                                if (yych <= '!')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_9;
+                            }
+                            else
+                            {
+                                if (yych <= '+')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                if (yych <= ',')
+                                {
+                                    goto basic_json_parser_10;
+                                }
+                                goto basic_json_parser_12;
+                            }
+                        }
+                        else
+                        {
+                            if (yych <= '9')
+                            {
+                                if (yych <= '/')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                if (yych <= '0')
+                                {
+                                    goto basic_json_parser_13;
+                                }
+                                goto basic_json_parser_15;
+                            }
+                            else
+                            {
+                                if (yych <= ':')
+                                {
+                                    goto basic_json_parser_17;
+                                }
+                                if (yych == '[')
+                                {
+                                    goto basic_json_parser_19;
+                                }
+                                goto basic_json_parser_4;
+                            }
+                        }
+                    }
+                    else
+                    {
+                        if (yych <= 't')
+                        {
+                            if (yych <= 'f')
+                            {
+                                if (yych <= ']')
+                                {
+                                    goto basic_json_parser_21;
+                                }
+                                if (yych <= 'e')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_23;
+                            }
+                            else
+                            {
+                                if (yych == 'n')
+                                {
+                                    goto basic_json_parser_24;
+                                }
+                                if (yych <= 's')
+                                {
+                                    goto basic_json_parser_4;
+                                }
+                                goto basic_json_parser_25;
+                            }
+                        }
+                        else
+                        {
+                            if (yych <= '|')
+                            {
+                                if (yych == '{')
+                                {
+                                    goto basic_json_parser_26;
+                                }
+                                goto basic_json_parser_4;
+                            }
+                            else
+                            {
+                                if (yych <= '}')
+                                {
+                                    goto basic_json_parser_28;
+                                }
+                                if (yych == 0xEF)
+                                {
+                                    goto basic_json_parser_30;
+                                }
+                                goto basic_json_parser_4;
+                            }
+                        }
+                    }
+basic_json_parser_2:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_of_input;
+                        break;
+                    }
+basic_json_parser_4:
+                    ++m_cursor;
+basic_json_parser_5:
+                    {
+                        last_token_type = token_type::parse_error;
+                        break;
+                    }
+basic_json_parser_6:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 32)
+                    {
+                        goto basic_json_parser_6;
+                    }
+                    {
+                        continue;
+                    }
+basic_json_parser_9:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych <= 0x1F)
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_10:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::value_separator;
+                        break;
+                    }
+basic_json_parser_12:
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    if (yych <= '0')
+                    {
+                        goto basic_json_parser_13;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_15;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_13:
+                    yyaccept = 1;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych <= 'D')
+                    {
+                        if (yych == '.')
+                        {
+                            goto basic_json_parser_37;
+                        }
+                    }
+                    else
+                    {
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                    }
+basic_json_parser_14:
+                    {
+                        last_token_type = token_type::value_number;
+                        break;
+                    }
+basic_json_parser_15:
+                    yyaccept = 1;
+                    m_marker = ++m_cursor;
+                    if ((m_limit - m_cursor) < 3)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yybm[0 + yych] & 64)
+                    {
+                        goto basic_json_parser_15;
+                    }
+                    if (yych <= 'D')
+                    {
+                        if (yych == '.')
+                        {
+                            goto basic_json_parser_37;
+                        }
+                        goto basic_json_parser_14;
+                    }
+                    else
+                    {
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        goto basic_json_parser_14;
+                    }
+basic_json_parser_17:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::name_separator;
+                        break;
+                    }
+basic_json_parser_19:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::begin_array;
+                        break;
+                    }
+basic_json_parser_21:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_array;
+                        break;
+                    }
+basic_json_parser_23:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'a')
+                    {
+                        goto basic_json_parser_39;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_24:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'u')
+                    {
+                        goto basic_json_parser_40;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_25:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 'r')
+                    {
+                        goto basic_json_parser_41;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_26:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::begin_object;
+                        break;
+                    }
+basic_json_parser_28:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::end_object;
+                        break;
+                    }
+basic_json_parser_30:
+                    yyaccept = 0;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych == 0xBB)
+                    {
+                        goto basic_json_parser_42;
+                    }
+                    goto basic_json_parser_5;
+basic_json_parser_31:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+basic_json_parser_32:
+                    if (yybm[0 + yych] & 128)
+                    {
+                        goto basic_json_parser_31;
+                    }
+                    if (yych <= 0x1F)
+                    {
+                        goto basic_json_parser_33;
+                    }
+                    if (yych <= '"')
+                    {
+                        goto basic_json_parser_34;
+                    }
+                    goto basic_json_parser_36;
+basic_json_parser_33:
+                    m_cursor = m_marker;
+                    if (yyaccept == 0)
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    else
+                    {
+                        goto basic_json_parser_14;
+                    }
+basic_json_parser_34:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::value_string;
+                        break;
+                    }
+basic_json_parser_36:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 'e')
+                    {
+                        if (yych <= '/')
+                        {
+                            if (yych == '"')
+                            {
+                                goto basic_json_parser_31;
+                            }
+                            if (yych <= '.')
+                            {
+                                goto basic_json_parser_33;
+                            }
+                            goto basic_json_parser_31;
+                        }
+                        else
+                        {
+                            if (yych <= '\\')
+                            {
+                                if (yych <= '[')
+                                {
+                                    goto basic_json_parser_33;
+                                }
+                                goto basic_json_parser_31;
+                            }
+                            else
+                            {
+                                if (yych == 'b')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                goto basic_json_parser_33;
+                            }
+                        }
+                    }
+                    else
+                    {
+                        if (yych <= 'q')
+                        {
+                            if (yych <= 'f')
+                            {
+                                goto basic_json_parser_31;
+                            }
+                            if (yych == 'n')
+                            {
+                                goto basic_json_parser_31;
+                            }
+                            goto basic_json_parser_33;
+                        }
+                        else
+                        {
+                            if (yych <= 's')
+                            {
+                                if (yych <= 'r')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                goto basic_json_parser_33;
+                            }
+                            else
+                            {
+                                if (yych <= 't')
+                                {
+                                    goto basic_json_parser_31;
+                                }
+                                if (yych <= 'u')
+                                {
+                                    goto basic_json_parser_43;
+                                }
+                                goto basic_json_parser_33;
+                            }
+                        }
+                    }
+basic_json_parser_37:
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_33;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_44;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_38:
+                    yych = *++m_cursor;
+                    if (yych <= ',')
+                    {
+                        if (yych == '+')
+                        {
+                            goto basic_json_parser_46;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= '-')
+                        {
+                            goto basic_json_parser_46;
+                        }
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_47;
+                        }
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_39:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
+                    {
+                        goto basic_json_parser_49;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_40:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
+                    {
+                        goto basic_json_parser_50;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_41:
+                    yych = *++m_cursor;
+                    if (yych == 'u')
+                    {
+                        goto basic_json_parser_51;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_42:
+                    yych = *++m_cursor;
+                    if (yych == 0xBF)
+                    {
+                        goto basic_json_parser_52;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_43:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_54;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_54;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_54;
+                        }
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_44:
+                    yyaccept = 1;
+                    m_marker = ++m_cursor;
+                    if ((m_limit - m_cursor) < 3)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 'D')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_14;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_44;
+                        }
+                        goto basic_json_parser_14;
+                    }
+                    else
+                    {
+                        if (yych <= 'E')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        if (yych == 'e')
+                        {
+                            goto basic_json_parser_38;
+                        }
+                        goto basic_json_parser_14;
+                    }
+basic_json_parser_46:
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_33;
+                    }
+                    if (yych >= ':')
+                    {
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_47:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_14;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_47;
+                    }
+                    goto basic_json_parser_14;
+basic_json_parser_49:
+                    yych = *++m_cursor;
+                    if (yych == 's')
+                    {
+                        goto basic_json_parser_55;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_50:
+                    yych = *++m_cursor;
+                    if (yych == 'l')
+                    {
+                        goto basic_json_parser_56;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_51:
+                    yych = *++m_cursor;
+                    if (yych == 'e')
+                    {
+                        goto basic_json_parser_58;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_52:
+                    ++m_cursor;
+                    {
+                        continue;
+                    }
+basic_json_parser_54:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_60;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_60;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_60;
+                        }
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_55:
+                    yych = *++m_cursor;
+                    if (yych == 'e')
+                    {
+                        goto basic_json_parser_61;
+                    }
+                    goto basic_json_parser_33;
+basic_json_parser_56:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::literal_null;
+                        break;
+                    }
+basic_json_parser_58:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::literal_true;
+                        break;
+                    }
+basic_json_parser_60:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_63;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_63;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_63;
+                        }
+                        goto basic_json_parser_33;
+                    }
+basic_json_parser_61:
+                    ++m_cursor;
+                    {
+                        last_token_type = token_type::literal_false;
+                        break;
+                    }
+basic_json_parser_63:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        yyfill();    // LCOV_EXCL_LINE;
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '@')
+                    {
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= '9')
+                        {
+                            goto basic_json_parser_31;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                    else
+                    {
+                        if (yych <= 'F')
+                        {
+                            goto basic_json_parser_31;
+                        }
+                        if (yych <= '`')
+                        {
+                            goto basic_json_parser_33;
+                        }
+                        if (yych <= 'f')
+                        {
+                            goto basic_json_parser_31;
+                        }
+                        goto basic_json_parser_33;
+                    }
+                }
+
+            }
+
+            return last_token_type;
+        }
+
+        /// append data from the stream to the internal buffer
+        void yyfill() noexcept
+        {
+            if (m_stream == nullptr or not * m_stream)
+            {
+                return;
+            }
+
+            const auto offset_start = m_start - m_content;
+            const auto offset_marker = m_marker - m_start;
+            const auto offset_cursor = m_cursor - m_start;
+
+            m_buffer.erase(0, static_cast<size_t>(offset_start));
+            std::string line;
+            assert(m_stream != nullptr);
+            std::getline(*m_stream, line);
+            m_buffer += "\n" + line; // add line with newline symbol
+
+            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
+            assert(m_content != nullptr);
+            m_start  = m_content;
+            m_marker = m_start + offset_marker;
+            m_cursor = m_start + offset_cursor;
+            m_limit  = m_start + m_buffer.size() - 1;
+        }
+
+        /// return string representation of last read token
+        string_t get_token_string() const
+        {
+            assert(m_start != nullptr);
+            return string_t(reinterpret_cast<typename string_t::const_pointer>(m_start),
+                            static_cast<size_t>(m_cursor - m_start));
+        }
+
+        /*!
+        @brief return string value for string tokens
+
+        The function iterates the characters between the opening and closing
+        quotes of the string value. The complete string is the range
+        [m_start,m_cursor). Consequently, we iterate from m_start+1 to
+        m_cursor-1.
+
+        We differentiate two cases:
+
+        1. Escaped characters. In this case, a new character is constructed
+           according to the nature of the escape. Some escapes create new
+           characters (e.g., `"\\n"` is replaced by `"\n"`), some are copied
+           as is (e.g., `"\\\\"`). Furthermore, Unicode escapes of the shape
+           `"\\uxxxx"` need special care. In this case, to_unicode takes care
+           of the construction of the values.
+        2. Unescaped characters are copied as is.
+
+        @pre `m_cursor - m_start >= 2`, meaning the length of the last token
+        is at least 2 bytes which is trivially true for any string (which
+        consists of at least two quotes).
+
+            " c1 c2 c3 ... "
+            ^                ^
+            m_start          m_cursor
+
+        @complexity Linear in the length of the string.\n
+
+        Lemma: The loop body will always terminate.\n
+
+        Proof (by contradiction): Assume the loop body does not terminate. As
+        the loop body does not contain another loop, one of the called
+        functions must never return. The called functions are `std::strtoul`
+        and to_unicode. Neither function can loop forever, so the loop body
+        will never loop forever which contradicts the assumption that the loop
+        body does not terminate, q.e.d.\n
+
+        Lemma: The loop condition for the for loop is eventually false.\n
+
+        Proof (by contradiction): Assume the loop does not terminate. Due to
+        the above lemma, this can only be due to a tautological loop
+        condition; that is, the loop condition i < m_cursor - 1 must always be
+        true. Let x be the change of i for any loop iteration. Then
+        m_start + 1 + x < m_cursor - 1 must hold to loop indefinitely. This
+        can be rephrased to m_cursor - m_start - 2 > x. With the
+        precondition, we x <= 0, meaning that the loop condition holds
+        indefinitly if i is always decreased. However, observe that the value
+        of i is strictly increasing with each iteration, as it is incremented
+        by 1 in the iteration expression and never decremented inside the loop
+        body. Hence, the loop condition will eventually be false which
+        contradicts the assumption that the loop condition is a tautology,
+        q.e.d.
+
+        @return string value of current token without opening and closing
+        quotes
+        @throw std::out_of_range if to_unicode fails
+        */
+        string_t get_string() const
+        {
+            assert(m_cursor - m_start >= 2);
+
+            string_t result;
+            result.reserve(static_cast<size_t>(m_cursor - m_start - 2));
+
+            // iterate the result between the quotes
+            for (const lexer_char_t* i = m_start + 1; i < m_cursor - 1; ++i)
+            {
+                // process escaped characters
+                if (*i == '\\')
+                {
+                    // read next character
+                    ++i;
+
+                    switch (*i)
+                    {
+                        // the default escapes
+                        case 't':
+                        {
+                            result += "\t";
+                            break;
+                        }
+                        case 'b':
+                        {
+                            result += "\b";
+                            break;
+                        }
+                        case 'f':
+                        {
+                            result += "\f";
+                            break;
+                        }
+                        case 'n':
+                        {
+                            result += "\n";
+                            break;
+                        }
+                        case 'r':
+                        {
+                            result += "\r";
+                            break;
+                        }
+                        case '\\':
+                        {
+                            result += "\\";
+                            break;
+                        }
+                        case '/':
+                        {
+                            result += "/";
+                            break;
+                        }
+                        case '"':
+                        {
+                            result += "\"";
+                            break;
+                        }
+
+                        // unicode
+                        case 'u':
+                        {
+                            // get code xxxx from uxxxx
+                            auto codepoint = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>(i + 1),
+                                                          4).c_str(), nullptr, 16);
+
+                            // check if codepoint is a high surrogate
+                            if (codepoint >= 0xD800 and codepoint <= 0xDBFF)
+                            {
+                                // make sure there is a subsequent unicode
+                                if ((i + 6 >= m_limit) or * (i + 5) != '\\' or * (i + 6) != 'u')
+                                {
+                                    throw std::invalid_argument("missing low surrogate");
+                                }
+
+                                // get code yyyy from uxxxx\uyyyy
+                                auto codepoint2 = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>
+                                                               (i + 7), 4).c_str(), nullptr, 16);
+                                result += to_unicode(codepoint, codepoint2);
+                                // skip the next 10 characters (xxxx\uyyyy)
+                                i += 10;
+                            }
+                            else
+                            {
+                                // add unicode character(s)
+                                result += to_unicode(codepoint);
+                                // skip the next four characters (xxxx)
+                                i += 4;
+                            }
+                            break;
+                        }
+                    }
+                }
+                else
+                {
+                    // all other characters are just copied to the end of the
+                    // string
+                    result.append(1, static_cast<typename string_t::value_type>(*i));
+                }
+            }
+
+            return result;
+        }
+
+        /*!
+        @brief parse floating point number
+
+        This function (and its overloads) serves to select the most approprate
+        standard floating point number parsing function based on the type
+        supplied via the first parameter.  Set this to @a
+        static_cast<number_float_t*>(nullptr).
+
+        @param[in] type  the @ref number_float_t in use
+
+        @param[in,out] endptr recieves a pointer to the first character after
+        the number
+
+        @return the floating point number
+        */
+        long double str_to_float_t(long double* /* type */, char** endptr) const
+        {
+            return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
+        }
+
+        /*!
+        @brief parse floating point number
+
+        This function (and its overloads) serves to select the most approprate
+        standard floating point number parsing function based on the type
+        supplied via the first parameter.  Set this to @a
+        static_cast<number_float_t*>(nullptr).
+
+        @param[in] type  the @ref number_float_t in use
+
+        @param[in,out] endptr  recieves a pointer to the first character after
+        the number
+
+        @return the floating point number
+        */
+        double str_to_float_t(double* /* type */, char** endptr) const
+        {
+            return std::strtod(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
+        }
+
+        /*!
+        @brief parse floating point number
+
+        This function (and its overloads) serves to select the most approprate
+        standard floating point number parsing function based on the type
+        supplied via the first parameter.  Set this to @a
+        static_cast<number_float_t*>(nullptr).
+
+        @param[in] type  the @ref number_float_t in use
+
+        @param[in,out] endptr  recieves a pointer to the first character after
+        the number
+
+        @return the floating point number
+        */
+        float str_to_float_t(float* /* type */, char** endptr) const
+        {
+            return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
+        }
+
+        /*!
+        @brief return number value for number tokens
+
+        This function translates the last token into the most appropriate
+        number type (either integer, unsigned integer or floating point),
+        which is passed back to the caller via the result parameter.
+
+        This function parses the integer component up to the radix point or
+        exponent while collecting information about the 'floating point
+        representation', which it stores in the result parameter. If there is
+        no radix point or exponent, and the number can fit into a @ref
+        number_integer_t or @ref number_unsigned_t then it sets the result
+        parameter accordingly.
+
+        If the number is a floating point number the number is then parsed
+        using @a std:strtod (or @a std:strtof or @a std::strtold).
+
+        @param[out] result  @ref basic_json object to receive the number, or
+        NAN if the conversion read past the current token. The latter case
+        needs to be treated by the caller function.
+        */
+        void get_number(basic_json& result) const
+        {
+            assert(m_start != nullptr);
+
+            const lexer::lexer_char_t* curptr = m_start;
+
+            // accumulate the integer conversion result (unsigned for now)
+            number_unsigned_t value = 0;
+
+            // maximum absolute value of the relevant integer type
+            number_unsigned_t max;
+
+            // temporarily store the type to avoid unecessary bitfield access
+            value_t type;
+
+            // look for sign
+            if (*curptr == '-')
+            {
+                type = value_t::number_integer;
+                max = static_cast<uint64_t>((std::numeric_limits<number_integer_t>::max)()) + 1;
+                curptr++;
+            }
+            else
+            {
+                type = value_t::number_unsigned;
+                max = static_cast<uint64_t>((std::numeric_limits<number_unsigned_t>::max)());
+            }
+
+            // count the significant figures
+            for (; curptr < m_cursor; curptr++)
+            {
+                // quickly skip tests if a digit
+                if (*curptr < '0' || *curptr > '9')
+                {
+                    if (*curptr == '.')
+                    {
+                        // don't count '.' but change to float
+                        type = value_t::number_float;
+                        continue;
+                    }
+                    // assume exponent (if not then will fail parse): change to
+                    // float, stop counting and record exponent details
+                    type = value_t::number_float;
+                    break;
+                }
+
+                // skip if definitely not an integer
+                if (type != value_t::number_float)
+                {
+                    // multiply last value by ten and add the new digit
+                    auto temp = value * 10 + *curptr - '0';
+
+                    // test for overflow
+                    if (temp < value || temp > max)
+                    {
+                        // overflow
+                        type = value_t::number_float;
+                    }
+                    else
+                    {
+                        // no overflow - save it
+                        value = temp;
+                    }
+                }
+            }
+
+            // save the value (if not a float)
+            if (type == value_t::number_unsigned)
+            {
+                result.m_value.number_unsigned = value;
+            }
+            else if (type == value_t::number_integer)
+            {
+                result.m_value.number_integer = -static_cast<number_integer_t>(value);
+            }
+            else
+            {
+                // parse with strtod
+                result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
+            }
+
+            // save the type
+            result.m_type = type;
+        }
+
+      private:
+        /// optional input stream
+        std::istream* m_stream = nullptr;
+        /// the buffer
+        string_t m_buffer;
+        /// the buffer pointer
+        const lexer_char_t* m_content = nullptr;
+        /// pointer to the beginning of the current symbol
+        const lexer_char_t* m_start = nullptr;
+        /// pointer for backtracking information
+        const lexer_char_t* m_marker = nullptr;
+        /// pointer to the current symbol
+        const lexer_char_t* m_cursor = nullptr;
+        /// pointer to the end of the buffer
+        const lexer_char_t* m_limit = nullptr;
+        /// the last token type
+        token_type last_token_type = token_type::end_of_input;
+    };
+
+    /*!
+    @brief syntax analysis
+
+    This class implements a recursive decent parser.
+    */
+    class parser
+    {
+      public:
+        /// constructor for strings
+        parser(const string_t& s, const parser_callback_t cb = nullptr) noexcept
+            : callback(cb), m_lexer(s)
+        {
+            // read first token
+            get_token();
+        }
+
+        /// a parser reading from an input stream
+        parser(std::istream& _is, const parser_callback_t cb = nullptr) noexcept
+            : callback(cb), m_lexer(&_is)
+        {
+            // read first token
+            get_token();
+        }
+
+        /// public parser interface
+        basic_json parse()
+        {
+            basic_json result = parse_internal(true);
+            result.assert_invariant();
+
+            expect(lexer::token_type::end_of_input);
+
+            // return parser result and replace it with null in case the
+            // top-level value was discarded by the callback function
+            return result.is_discarded() ? basic_json() : std::move(result);
+        }
+
+      private:
+        /// the actual parser
+        basic_json parse_internal(bool keep)
+        {
+            auto result = basic_json(value_t::discarded);
+
+            switch (last_token)
+            {
+                case lexer::token_type::begin_object:
+                {
+                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::object_start, result))))
+                    {
+                        // explicitly set result to object to cope with {}
+                        result.m_type = value_t::object;
+                        result.m_value = value_t::object;
+                    }
+
+                    // read next token
+                    get_token();
+
+                    // closing } -> we are done
+                    if (last_token == lexer::token_type::end_object)
+                    {
+                        get_token();
+                        if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
+                        {
+                            result = basic_json(value_t::discarded);
+                        }
+                        return result;
+                    }
+
+                    // no comma is expected here
+                    unexpect(lexer::token_type::value_separator);
+
+                    // otherwise: parse key-value pairs
+                    do
+                    {
+                        // ugly, but could be fixed with loop reorganization
+                        if (last_token == lexer::token_type::value_separator)
+                        {
+                            get_token();
+                        }
+
+                        // store key
+                        expect(lexer::token_type::value_string);
+                        const auto key = m_lexer.get_string();
+
+                        bool keep_tag = false;
+                        if (keep)
+                        {
+                            if (callback)
+                            {
+                                basic_json k(key);
+                                keep_tag = callback(depth, parse_event_t::key, k);
+                            }
+                            else
+                            {
+                                keep_tag = true;
+                            }
+                        }
+
+                        // parse separator (:)
+                        get_token();
+                        expect(lexer::token_type::name_separator);
+
+                        // parse and add value
+                        get_token();
+                        auto value = parse_internal(keep);
+                        if (keep and keep_tag and not value.is_discarded())
+                        {
+                            result[key] = std::move(value);
+                        }
+                    }
+                    while (last_token == lexer::token_type::value_separator);
+
+                    // closing }
+                    expect(lexer::token_type::end_object);
+                    get_token();
+                    if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
+                    {
+                        result = basic_json(value_t::discarded);
+                    }
+
+                    return result;
+                }
+
+                case lexer::token_type::begin_array:
+                {
+                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::array_start, result))))
+                    {
+                        // explicitly set result to object to cope with []
+                        result.m_type = value_t::array;
+                        result.m_value = value_t::array;
+                    }
+
+                    // read next token
+                    get_token();
+
+                    // closing ] -> we are done
+                    if (last_token == lexer::token_type::end_array)
+                    {
+                        get_token();
+                        if (callback and not callback(--depth, parse_event_t::array_end, result))
+                        {
+                            result = basic_json(value_t::discarded);
+                        }
+                        return result;
+                    }
+
+                    // no comma is expected here
+                    unexpect(lexer::token_type::value_separator);
+
+                    // otherwise: parse values
+                    do
+                    {
+                        // ugly, but could be fixed with loop reorganization
+                        if (last_token == lexer::token_type::value_separator)
+                        {
+                            get_token();
+                        }
+
+                        // parse value
+                        auto value = parse_internal(keep);
+                        if (keep and not value.is_discarded())
+                        {
+                            result.push_back(std::move(value));
+                        }
+                    }
+                    while (last_token == lexer::token_type::value_separator);
+
+                    // closing ]
+                    expect(lexer::token_type::end_array);
+                    get_token();
+                    if (keep and callback and not callback(--depth, parse_event_t::array_end, result))
+                    {
+                        result = basic_json(value_t::discarded);
+                    }
+
+                    return result;
+                }
+
+                case lexer::token_type::literal_null:
+                {
+                    get_token();
+                    result.m_type = value_t::null;
+                    break;
+                }
+
+                case lexer::token_type::value_string:
+                {
+                    const auto s = m_lexer.get_string();
+                    get_token();
+                    result = basic_json(s);
+                    break;
+                }
+
+                case lexer::token_type::literal_true:
+                {
+                    get_token();
+                    result.m_type = value_t::boolean;
+                    result.m_value = true;
+                    break;
+                }
+
+                case lexer::token_type::literal_false:
+                {
+                    get_token();
+                    result.m_type = value_t::boolean;
+                    result.m_value = false;
+                    break;
+                }
+
+                case lexer::token_type::value_number:
+                {
+                    m_lexer.get_number(result);
+                    get_token();
+                    break;
+                }
+
+                default:
+                {
+                    // the last token was unexpected
+                    unexpect(last_token);
+                }
+            }
+
+            if (keep and callback and not callback(depth, parse_event_t::value, result))
+            {
+                result = basic_json(value_t::discarded);
+            }
+            return result;
+        }
+
+        /// get next token from lexer
+        typename lexer::token_type get_token() noexcept
+        {
+            last_token = m_lexer.scan();
+            return last_token;
+        }
+
+        void expect(typename lexer::token_type t) const
+        {
+            if (t != last_token)
+            {
+                std::string error_msg = "parse error - unexpected ";
+                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
+                              "'") :
+                              lexer::token_type_name(last_token));
+                error_msg += "; expected " + lexer::token_type_name(t);
+                throw std::invalid_argument(error_msg);
+            }
+        }
+
+        void unexpect(typename lexer::token_type t) const
+        {
+            if (t == last_token)
+            {
+                std::string error_msg = "parse error - unexpected ";
+                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
+                              "'") :
+                              lexer::token_type_name(last_token));
+                throw std::invalid_argument(error_msg);
+            }
+        }
+
+      private:
+        /// current level of recursion
+        int depth = 0;
+        /// callback function
+        const parser_callback_t callback = nullptr;
+        /// the type of the last read token
+        typename lexer::token_type last_token = lexer::token_type::uninitialized;
+        /// the lexer
+        lexer m_lexer;
+    };
+
+  public:
+    /*!
+    @brief JSON Pointer
+
+    A JSON pointer defines a string syntax for identifying a specific value
+    within a JSON document. It can be used with functions `at` and
+    `operator[]`. Furthermore, JSON pointers are the base for JSON patches.
+
+    @sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
+
+    @since version 2.0.0
+    */
+    class json_pointer
+    {
+        /// allow basic_json to access private members
+        friend class basic_json;
+
+      public:
+        /*!
+        @brief create JSON pointer
+
+        Create a JSON pointer according to the syntax described in
+        [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3).
+
+        @param[in] s  string representing the JSON pointer; if omitted, the
+                      empty string is assumed which references the whole JSON
+                      value
+
+        @throw std::domain_error if reference token is nonempty and does not
+        begin with a slash (`/`); example: `"JSON pointer must be empty or
+        begin with /"`
+        @throw std::domain_error if a tilde (`~`) is not followed by `0`
+        (representing `~`) or `1` (representing `/`); example: `"escape error:
+        ~ must be followed with 0 or 1"`
+
+        @liveexample{The example shows the construction several valid JSON
+        pointers as well as the exceptional behavior.,json_pointer}
+
+        @since version 2.0.0
+        */
+        explicit json_pointer(const std::string& s = "")
+            : reference_tokens(split(s))
+        {}
+
+        /*!
+        @brief return a string representation of the JSON pointer
+
+        @invariant For each JSON pointer `ptr`, it holds:
+        @code {.cpp}
+        ptr == json_pointer(ptr.to_string());
+        @endcode
+
+        @return a string representation of the JSON pointer
+
+        @liveexample{The example shows the result of `to_string`.,
+        json_pointer__to_string}
+
+        @since version 2.0.0
+        */
+        std::string to_string() const noexcept
+        {
+            return std::accumulate(reference_tokens.begin(),
+                                   reference_tokens.end(), std::string{},
+                                   [](const std::string & a, const std::string & b)
+            {
+                return a + "/" + escape(b);
+            });
+        }
+
+        /// @copydoc to_string()
+        operator std::string() const
+        {
+            return to_string();
+        }
+
+      private:
+        /// remove and return last reference pointer
+        std::string pop_back()
+        {
+            if (is_root())
+            {
+                throw std::domain_error("JSON pointer has no parent");
+            }
+
+            auto last = reference_tokens.back();
+            reference_tokens.pop_back();
+            return last;
+        }
+
+        /// return whether pointer points to the root document
+        bool is_root() const
+        {
+            return reference_tokens.empty();
+        }
+
+        json_pointer top() const
+        {
+            if (is_root())
+            {
+                throw std::domain_error("JSON pointer has no parent");
+            }
+
+            json_pointer result = *this;
+            result.reference_tokens = {reference_tokens[0]};
+            return result;
+        }
+
+        /*!
+        @brief create and return a reference to the pointed to value
+
+        @complexity Linear in the number of reference tokens.
+        */
+        reference get_and_create(reference j) const
+        {
+            pointer result = &j;
+
+            // in case no reference tokens exist, return a reference to the
+            // JSON value j which will be overwritten by a primitive value
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (result->m_type)
+                {
+                    case value_t::null:
+                    {
+                        if (reference_token == "0")
+                        {
+                            // start a new array if reference token is 0
+                            result = &result->operator[](0);
+                        }
+                        else
+                        {
+                            // start a new object otherwise
+                            result = &result->operator[](reference_token);
+                        }
+                        break;
+                    }
+
+                    case value_t::object:
+                    {
+                        // create an entry in the object
+                        result = &result->operator[](reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        // create an entry in the array
+                        result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        break;
+                    }
+
+                    /*
+                    The following code is only reached if there exists a
+                    reference token _and_ the current value is primitive. In
+                    this case, we have an error situation, because primitive
+                    values may only occur as single value; that is, with an
+                    empty list of reference tokens.
+                    */
+                    default:
+                    {
+                        throw std::domain_error("invalid value to unflatten");
+                    }
+                }
+            }
+
+            return *result;
+        }
+
+        /*!
+        @brief return a reference to the pointed to value
+
+        @param[in] ptr  a JSON value
+
+        @return reference to the JSON value pointed to by the JSON pointer
+
+        @complexity Linear in the length of the JSON pointer.
+
+        @throw std::out_of_range      if the JSON pointer can not be resolved
+        @throw std::domain_error      if an array index begins with '0'
+        @throw std::invalid_argument  if an array index was not a number
+        */
+        reference get_unchecked(pointer ptr) const
+        {
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (ptr->m_type)
+                {
+                    case value_t::object:
+                    {
+                        // use unchecked object access
+                        ptr = &ptr->operator[](reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        // error condition (cf. RFC 6901, Sect. 4)
+                        if (reference_token.size() > 1 and reference_token[0] == '0')
+                        {
+                            throw std::domain_error("array index must not begin with '0'");
+                        }
+
+                        if (reference_token == "-")
+                        {
+                            // explicityly treat "-" as index beyond the end
+                            ptr = &ptr->operator[](ptr->m_value.array->size());
+                        }
+                        else
+                        {
+                            // convert array index to number; unchecked access
+                            ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        }
+                        break;
+                    }
+
+                    default:
+                    {
+                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                    }
+                }
+            }
+
+            return *ptr;
+        }
+
+        reference get_checked(pointer ptr) const
+        {
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (ptr->m_type)
+                {
+                    case value_t::object:
+                    {
+                        // note: at performs range check
+                        ptr = &ptr->at(reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        if (reference_token == "-")
+                        {
+                            // "-" always fails the range check
+                            throw std::out_of_range("array index '-' (" +
+                                                    std::to_string(ptr->m_value.array->size()) +
+                                                    ") is out of range");
+                        }
+
+                        // error condition (cf. RFC 6901, Sect. 4)
+                        if (reference_token.size() > 1 and reference_token[0] == '0')
+                        {
+                            throw std::domain_error("array index must not begin with '0'");
+                        }
+
+                        // note: at performs range check
+                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
+                        break;
+                    }
+
+                    default:
+                    {
+                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                    }
+                }
+            }
+
+            return *ptr;
+        }
+
+        /*!
+        @brief return a const reference to the pointed to value
+
+        @param[in] ptr  a JSON value
+
+        @return const reference to the JSON value pointed to by the JSON
+                pointer
+        */
+        const_reference get_unchecked(const_pointer ptr) const
+        {
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (ptr->m_type)
+                {
+                    case value_t::object:
+                    {
+                        // use unchecked object access
+                        ptr = &ptr->operator[](reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        if (reference_token == "-")
+                        {
+                            // "-" cannot be used for const access
+                            throw std::out_of_range("array index '-' (" +
+                                                    std::to_string(ptr->m_value.array->size()) +
+                                                    ") is out of range");
+                        }
+
+                        // error condition (cf. RFC 6901, Sect. 4)
+                        if (reference_token.size() > 1 and reference_token[0] == '0')
+                        {
+                            throw std::domain_error("array index must not begin with '0'");
+                        }
+
+                        // use unchecked array access
+                        ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        break;
+                    }
+
+                    default:
+                    {
+                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                    }
+                }
+            }
+
+            return *ptr;
+        }
+
+        const_reference get_checked(const_pointer ptr) const
+        {
+            for (const auto& reference_token : reference_tokens)
+            {
+                switch (ptr->m_type)
+                {
+                    case value_t::object:
+                    {
+                        // note: at performs range check
+                        ptr = &ptr->at(reference_token);
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        if (reference_token == "-")
+                        {
+                            // "-" always fails the range check
+                            throw std::out_of_range("array index '-' (" +
+                                                    std::to_string(ptr->m_value.array->size()) +
+                                                    ") is out of range");
+                        }
+
+                        // error condition (cf. RFC 6901, Sect. 4)
+                        if (reference_token.size() > 1 and reference_token[0] == '0')
+                        {
+                            throw std::domain_error("array index must not begin with '0'");
+                        }
+
+                        // note: at performs range check
+                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
+                        break;
+                    }
+
+                    default:
+                    {
+                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                    }
+                }
+            }
+
+            return *ptr;
+        }
+
+        /// split the string input to reference tokens
+        static std::vector<std::string> split(std::string reference_string)
+        {
+            std::vector<std::string> result;
+
+            // special case: empty reference string -> no reference tokens
+            if (reference_string.empty())
+            {
+                return result;
+            }
+
+            // check if nonempty reference string begins with slash
+            if (reference_string[0] != '/')
+            {
+                throw std::domain_error("JSON pointer must be empty or begin with '/'");
+            }
+
+            // extract the reference tokens:
+            // - slash: position of the last read slash (or end of string)
+            // - start: position after the previous slash
+            for (
+                // search for the first slash after the first character
+                size_t slash = reference_string.find_first_of("/", 1),
+                // set the beginning of the first reference token
+                start = 1;
+                // we can stop if start == string::npos+1 = 0
+                start != 0;
+                // set the beginning of the next reference token
+                // (will eventually be 0 if slash == std::string::npos)
+                start = slash + 1,
+                // find next slash
+                slash = reference_string.find_first_of("/", start))
+            {
+                // use the text between the beginning of the reference token
+                // (start) and the last slash (slash).
+                auto reference_token = reference_string.substr(start, slash - start);
+
+                // check reference tokens are properly escaped
+                for (size_t pos = reference_token.find_first_of("~");
+                        pos != std::string::npos;
+                        pos = reference_token.find_first_of("~", pos + 1))
+                {
+                    assert(reference_token[pos] == '~');
+
+                    // ~ must be followed by 0 or 1
+                    if (pos == reference_token.size() - 1 or
+                            (reference_token[pos + 1] != '0' and
+                             reference_token[pos + 1] != '1'))
+                    {
+                        throw std::domain_error("escape error: '~' must be followed with '0' or '1'");
+                    }
+                }
+
+                // finally, store the reference token
+                unescape(reference_token);
+                result.push_back(reference_token);
+            }
+
+            return result;
+        }
+
+      private:
+        /*!
+        @brief replace all occurrences of a substring by another string
+
+        @param[in,out] s  the string to manipulate
+        @param[in]     f  the substring to replace with @a t
+        @param[in]     t  the string to replace @a f
+
+        @return The string @a s where all occurrences of @a f are replaced
+                with @a t.
+
+        @pre The search string @a f must not be empty.
+
+        @since version 2.0.0
+        */
+        static void replace_substring(std::string& s,
+                                      const std::string& f,
+                                      const std::string& t)
+        {
+            assert(not f.empty());
+
+            for (
+                size_t pos = s.find(f);         // find first occurrence of f
+                pos != std::string::npos;       // make sure f was found
+                s.replace(pos, f.size(), t),    // replace with t
+                pos = s.find(f, pos + t.size()) // find next occurrence of f
+            );
+        }
+
+        /// escape tilde and slash
+        static std::string escape(std::string s)
+        {
+            // escape "~"" to "~0" and "/" to "~1"
+            replace_substring(s, "~", "~0");
+            replace_substring(s, "/", "~1");
+            return s;
+        }
+
+        /// unescape tilde and slash
+        static void unescape(std::string& s)
+        {
+            // first transform any occurrence of the sequence '~1' to '/'
+            replace_substring(s, "~1", "/");
+            // then transform any occurrence of the sequence '~0' to '~'
+            replace_substring(s, "~0", "~");
+        }
+
+        /*!
+        @param[in] reference_string  the reference string to the current value
+        @param[in] value             the value to consider
+        @param[in,out] result        the result object to insert values to
+
+        @note Empty objects or arrays are flattened to `null`.
+        */
+        static void flatten(const std::string& reference_string,
+                            const basic_json& value,
+                            basic_json& result)
+        {
+            switch (value.m_type)
+            {
+                case value_t::array:
+                {
+                    if (value.m_value.array->empty())
+                    {
+                        // flatten empty array as null
+                        result[reference_string] = nullptr;
+                    }
+                    else
+                    {
+                        // iterate array and use index as reference string
+                        for (size_t i = 0; i < value.m_value.array->size(); ++i)
+                        {
+                            flatten(reference_string + "/" + std::to_string(i),
+                                    value.m_value.array->operator[](i), result);
+                        }
+                    }
+                    break;
+                }
+
+                case value_t::object:
+                {
+                    if (value.m_value.object->empty())
+                    {
+                        // flatten empty object as null
+                        result[reference_string] = nullptr;
+                    }
+                    else
+                    {
+                        // iterate object and use keys as reference string
+                        for (const auto& element : *value.m_value.object)
+                        {
+                            flatten(reference_string + "/" + escape(element.first),
+                                    element.second, result);
+                        }
+                    }
+                    break;
+                }
+
+                default:
+                {
+                    // add primitive value with its reference string
+                    result[reference_string] = value;
+                    break;
+                }
+            }
+        }
+
+        /*!
+        @param[in] value  flattened JSON
+
+        @return unflattened JSON
+        */
+        static basic_json unflatten(const basic_json& value)
+        {
+            if (not value.is_object())
+            {
+                throw std::domain_error("only objects can be unflattened");
+            }
+
+            basic_json result;
+
+            // iterate the JSON object values
+            for (const auto& element : *value.m_value.object)
+            {
+                if (not element.second.is_primitive())
+                {
+                    throw std::domain_error("values in object must be primitive");
+                }
+
+                // assign value to reference pointed to by JSON pointer; Note
+                // that if the JSON pointer is "" (i.e., points to the whole
+                // value), function get_and_create returns a reference to
+                // result itself. An assignment will then create a primitive
+                // value.
+                json_pointer(element.first).get_and_create(result) = element.second;
+            }
+
+            return result;
+        }
+
+      private:
+        /// the reference tokens
+        std::vector<std::string> reference_tokens {};
+    };
+
+    //////////////////////////
+    // JSON Pointer support //
+    //////////////////////////
+
+    /// @name JSON Pointer functions
+    /// @{
+
+    /*!
+    @brief access specified element via JSON Pointer
+
+    Uses a JSON pointer to retrieve a reference to the respective JSON value.
+    No bound checking is performed. Similar to @ref operator[](const typename
+    object_t::key_type&), `null` values are created in arrays and objects if
+    necessary.
+
+    In particular:
+    - If the JSON pointer points to an object key that does not exist, it
+      is created an filled with a `null` value before a reference to it
+      is returned.
+    - If the JSON pointer points to an array index that does not exist, it
+      is created an filled with a `null` value before a reference to it
+      is returned. All indices between the current maximum and the given
+      index are also filled with `null`.
+    - The special value `-` is treated as a synonym for the index past the
+      end.
+
+    @param[in] ptr  a JSON pointer
+
+    @return reference to the element pointed to by @a ptr
+
+    @complexity Constant.
+
+    @throw std::out_of_range      if the JSON pointer can not be resolved
+    @throw std::domain_error      if an array index begins with '0'
+    @throw std::invalid_argument  if an array index was not a number
+
+    @liveexample{The behavior is shown in the example.,operatorjson_pointer}
+
+    @since version 2.0.0
+    */
+    reference operator[](const json_pointer& ptr)
+    {
+        return ptr.get_unchecked(this);
+    }
+
+    /*!
+    @brief access specified element via JSON Pointer
+
+    Uses a JSON pointer to retrieve a reference to the respective JSON value.
+    No bound checking is performed. The function does not change the JSON
+    value; no `null` values are created. In particular, the the special value
+    `-` yields an exception.
+
+    @param[in] ptr  JSON pointer to the desired element
+
+    @return const reference to the element pointed to by @a ptr
+
+    @complexity Constant.
+
+    @throw std::out_of_range      if the JSON pointer can not be resolved
+    @throw std::domain_error      if an array index begins with '0'
+    @throw std::invalid_argument  if an array index was not a number
+
+    @liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
+
+    @since version 2.0.0
+    */
+    const_reference operator[](const json_pointer& ptr) const
+    {
+        return ptr.get_unchecked(this);
+    }
+
+    /*!
+    @brief access specified element via JSON Pointer
+
+    Returns a reference to the element at with specified JSON pointer @a ptr,
+    with bounds checking.
+
+    @param[in] ptr  JSON pointer to the desired element
+
+    @return reference to the element pointed to by @a ptr
+
+    @complexity Constant.
+
+    @throw std::out_of_range      if the JSON pointer can not be resolved
+    @throw std::domain_error      if an array index begins with '0'
+    @throw std::invalid_argument  if an array index was not a number
+
+    @liveexample{The behavior is shown in the example.,at_json_pointer}
+
+    @since version 2.0.0
+    */
+    reference at(const json_pointer& ptr)
+    {
+        return ptr.get_checked(this);
+    }
+
+    /*!
+    @brief access specified element via JSON Pointer
+
+    Returns a const reference to the element at with specified JSON pointer @a
+    ptr, with bounds checking.
+
+    @param[in] ptr  JSON pointer to the desired element
+
+    @return reference to the element pointed to by @a ptr
+
+    @complexity Constant.
+
+    @throw std::out_of_range      if the JSON pointer can not be resolved
+    @throw std::domain_error      if an array index begins with '0'
+    @throw std::invalid_argument  if an array index was not a number
+
+    @liveexample{The behavior is shown in the example.,at_json_pointer_const}
+
+    @since version 2.0.0
+    */
+    const_reference at(const json_pointer& ptr) const
+    {
+        return ptr.get_checked(this);
+    }
+
+    /*!
+    @brief return flattened JSON value
+
+    The function creates a JSON object whose keys are JSON pointers (see [RFC
+    6901](https://tools.ietf.org/html/rfc6901)) and whose values are all
+    primitive. The original JSON value can be restored using the @ref
+    unflatten() function.
+
+    @return an object that maps JSON pointers to primitve values
+
+    @note Empty objects and arrays are flattened to `null` and will not be
+          reconstructed correctly by the @ref unflatten() function.
+
+    @complexity Linear in the size the JSON value.
+
+    @liveexample{The following code shows how a JSON object is flattened to an
+    object whose keys consist of JSON pointers.,flatten}
+
+    @sa @ref unflatten() for the reverse function
+
+    @since version 2.0.0
+    */
+    basic_json flatten() const
+    {
+        basic_json result(value_t::object);
+        json_pointer::flatten("", *this, result);
+        return result;
+    }
+
+    /*!
+    @brief unflatten a previously flattened JSON value
+
+    The function restores the arbitrary nesting of a JSON value that has been
+    flattened before using the @ref flatten() function. The JSON value must
+    meet certain constraints:
+    1. The value must be an object.
+    2. The keys must be JSON pointers (see
+       [RFC 6901](https://tools.ietf.org/html/rfc6901))
+    3. The mapped values must be primitive JSON types.
+
+    @return the original JSON from a flattened version
+
+    @note Empty objects and arrays are flattened by @ref flatten() to `null`
+          values and can not unflattened to their original type. Apart from
+          this example, for a JSON value `j`, the following is always true:
+          `j == j.flatten().unflatten()`.
+
+    @complexity Linear in the size the JSON value.
+
+    @liveexample{The following code shows how a flattened JSON object is
+    unflattened into the original nested JSON object.,unflatten}
+
+    @sa @ref flatten() for the reverse function
+
+    @since version 2.0.0
+    */
+    basic_json unflatten() const
+    {
+        return json_pointer::unflatten(*this);
+    }
+
+    /// @}
+
+    //////////////////////////
+    // JSON Patch functions //
+    //////////////////////////
+
+    /// @name JSON Patch functions
+    /// @{
+
+    /*!
+    @brief applies a JSON patch
+
+    [JSON Patch](http://jsonpatch.com) defines a JSON document structure for
+    expressing a sequence of operations to apply to a JSON) document. With
+    this funcion, a JSON Patch is applied to the current JSON value by
+    executing all operations from the patch.
+
+    @param[in] json_patch  JSON patch document
+    @return patched document
+
+    @note The application of a patch is atomic: Either all operations succeed
+          and the patched document is returned or an exception is thrown. In
+          any case, the original value is not changed: the patch is applied
+          to a copy of the value.
+
+    @throw std::out_of_range if a JSON pointer inside the patch could not
+    be resolved successfully in the current JSON value; example: `"key baz
+    not found"`
+    @throw invalid_argument if the JSON patch is malformed (e.g., mandatory
+    attributes are missing); example: `"operation add must have member path"`
+
+    @complexity Linear in the size of the JSON value and the length of the
+    JSON patch. As usually only a fraction of the JSON value is affected by
+    the patch, the complexity can usually be neglected.
+
+    @liveexample{The following code shows how a JSON patch is applied to a
+    value.,patch}
+
+    @sa @ref diff -- create a JSON patch by comparing two JSON values
+
+    @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
+    @sa [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
+
+    @since version 2.0.0
+    */
+    basic_json patch(const basic_json& json_patch) const
+    {
+        // make a working copy to apply the patch to
+        basic_json result = *this;
+
+        // the valid JSON Patch operations
+        enum class patch_operations {add, remove, replace, move, copy, test, invalid};
+
+        const auto get_op = [](const std::string op)
+        {
+            if (op == "add")
+            {
+                return patch_operations::add;
+            }
+            if (op == "remove")
+            {
+                return patch_operations::remove;
+            }
+            if (op == "replace")
+            {
+                return patch_operations::replace;
+            }
+            if (op == "move")
+            {
+                return patch_operations::move;
+            }
+            if (op == "copy")
+            {
+                return patch_operations::copy;
+            }
+            if (op == "test")
+            {
+                return patch_operations::test;
+            }
+
+            return patch_operations::invalid;
+        };
+
+        // wrapper for "add" operation; add value at ptr
+        const auto operation_add = [&result](json_pointer & ptr, basic_json val)
+        {
+            // adding to the root of the target document means replacing it
+            if (ptr.is_root())
+            {
+                result = val;
+            }
+            else
+            {
+                // make sure the top element of the pointer exists
+                json_pointer top_pointer = ptr.top();
+                if (top_pointer != ptr)
+                {
+                    basic_json& x = result.at(top_pointer);
+                }
+
+                // get reference to parent of JSON pointer ptr
+                const auto last_path = ptr.pop_back();
+                basic_json& parent = result[ptr];
+
+                switch (parent.m_type)
+                {
+                    case value_t::null:
+                    case value_t::object:
+                    {
+                        // use operator[] to add value
+                        parent[last_path] = val;
+                        break;
+                    }
+
+                    case value_t::array:
+                    {
+                        if (last_path == "-")
+                        {
+                            // special case: append to back
+                            parent.push_back(val);
+                        }
+                        else
+                        {
+                            const auto idx = std::stoi(last_path);
+                            if (static_cast<size_type>(idx) > parent.size())
+                            {
+                                // avoid undefined behavior
+                                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+                            }
+                            else
+                            {
+                                // default case: insert add offset
+                                parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
+                            }
+                        }
+                        break;
+                    }
+
+                    default:
+                    {
+                        // if there exists a parent it cannot be primitive
+                        assert(false);  // LCOV_EXCL_LINE
+                    }
+                }
+            }
+        };
+
+        // wrapper for "remove" operation; remove value at ptr
+        const auto operation_remove = [&result](json_pointer & ptr)
+        {
+            // get reference to parent of JSON pointer ptr
+            const auto last_path = ptr.pop_back();
+            basic_json& parent = result.at(ptr);
+
+            // remove child
+            if (parent.is_object())
+            {
+                // perform range check
+                auto it = parent.find(last_path);
+                if (it != parent.end())
+                {
+                    parent.erase(it);
+                }
+                else
+                {
+                    throw std::out_of_range("key '" + last_path + "' not found");
+                }
+            }
+            else if (parent.is_array())
+            {
+                // note erase performs range check
+                parent.erase(static_cast<size_type>(std::stoi(last_path)));
+            }
+        };
+
+        // type check
+        if (not json_patch.is_array())
+        {
+            // a JSON patch must be an array of objects
+            throw std::invalid_argument("JSON patch must be an array of objects");
+        }
+
+        // iterate and apply th eoperations
+        for (const auto& val : json_patch)
+        {
+            // wrapper to get a value for an operation
+            const auto get_value = [&val](const std::string & op,
+                                          const std::string & member,
+                                          bool string_type) -> basic_json&
+            {
+                // find value
+                auto it = val.m_value.object->find(member);
+
+                // context-sensitive error message
+                const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";
+
+                // check if desired value is present
+                if (it == val.m_value.object->end())
+                {
+                    throw std::invalid_argument(error_msg + " must have member '" + member + "'");
+                }
+
+                // check if result is of type string
+                if (string_type and not it->second.is_string())
+                {
+                    throw std::invalid_argument(error_msg + " must have string member '" + member + "'");
+                }
+
+                // no error: return value
+                return it->second;
+            };
+
+            // type check
+            if (not val.is_object())
+            {
+                throw std::invalid_argument("JSON patch must be an array of objects");
+            }
+
+            // collect mandatory members
+            const std::string op = get_value("op", "op", true);
+            const std::string path = get_value(op, "path", true);
+            json_pointer ptr(path);
+
+            switch (get_op(op))
+            {
+                case patch_operations::add:
+                {
+                    operation_add(ptr, get_value("add", "value", false));
+                    break;
+                }
+
+                case patch_operations::remove:
+                {
+                    operation_remove(ptr);
+                    break;
+                }
+
+                case patch_operations::replace:
+                {
+                    // the "path" location must exist - use at()
+                    result.at(ptr) = get_value("replace", "value", false);
+                    break;
+                }
+
+                case patch_operations::move:
+                {
+                    const std::string from_path = get_value("move", "from", true);
+                    json_pointer from_ptr(from_path);
+
+                    // the "from" location must exist - use at()
+                    basic_json v = result.at(from_ptr);
+
+                    // The move operation is functionally identical to a
+                    // "remove" operation on the "from" location, followed
+                    // immediately by an "add" operation at the target
+                    // location with the value that was just removed.
+                    operation_remove(from_ptr);
+                    operation_add(ptr, v);
+                    break;
+                }
+
+                case patch_operations::copy:
+                {
+                    const std::string from_path = get_value("copy", "from", true);;
+                    const json_pointer from_ptr(from_path);
+
+                    // the "from" location must exist - use at()
+                    result[ptr] = result.at(from_ptr);
+                    break;
+                }
+
+                case patch_operations::test:
+                {
+                    bool success = false;
+                    try
+                    {
+                        // check if "value" matches the one at "path"
+                        // the "path" location must exist - use at()
+                        success = (result.at(ptr) == get_value("test", "value", false));
+                    }
+                    catch (std::out_of_range&)
+                    {
+                        // ignore out of range errors: success remains false
+                    }
+
+                    // throw an exception if test fails
+                    if (not success)
+                    {
+                        throw std::domain_error("unsuccessful: " + val.dump());
+                    }
+
+                    break;
+                }
+
+                case patch_operations::invalid:
+                {
+                    // op must be "add", "remove", "replace", "move", "copy", or
+                    // "test"
+                    throw std::invalid_argument("operation value '" + op + "' is invalid");
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /*!
+    @brief creates a diff as a JSON patch
+
+    Creates a [JSON Patch](http://jsonpatch.com) so that value @a source can
+    be changed into the value @a target by calling @ref patch function.
+
+    @invariant For two JSON values @a source and @a target, the following code
+    yields always `true`:
+    @code {.cpp}
+    source.patch(diff(source, target)) == target;
+    @endcode
+
+    @note Currently, only `remove`, `add`, and `replace` operations are
+          generated.
+
+    @param[in] source  JSON value to copare from
+    @param[in] target  JSON value to copare against
+    @param[in] path    helper value to create JSON pointers
+
+    @return a JSON patch to convert the @a source to @a target
+
+    @complexity Linear in the lengths of @a source and @a target.
+
+    @liveexample{The following code shows how a JSON patch is created as a
+    diff for two JSON values.,diff}
+
+    @sa @ref patch -- apply a JSON patch
+
+    @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
+
+    @since version 2.0.0
+    */
+    static basic_json diff(const basic_json& source,
+                           const basic_json& target,
+                           std::string path = "")
+    {
+        // the patch
+        basic_json result(value_t::array);
+
+        // if the values are the same, return empty patch
+        if (source == target)
+        {
+            return result;
+        }
+
+        if (source.type() != target.type())
+        {
+            // different types: replace value
+            result.push_back(
+            {
+                {"op", "replace"},
+                {"path", path},
+                {"value", target}
+            });
+        }
+        else
+        {
+            switch (source.type())
+            {
+                case value_t::array:
+                {
+                    // first pass: traverse common elements
+                    size_t i = 0;
+                    while (i < source.size() and i < target.size())
+                    {
+                        // recursive call to compare array values at index i
+                        auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
+                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
+                        ++i;
+                    }
+
+                    // i now reached the end of at least one array
+                    // in a second pass, traverse the remaining elements
+
+                    // remove my remaining elements
+                    const auto end_index = static_cast<difference_type>(result.size());
+                    while (i < source.size())
+                    {
+                        // add operations in reverse order to avoid invalid
+                        // indices
+                        result.insert(result.begin() + end_index, object(
+                        {
+                            {"op", "remove"},
+                            {"path", path + "/" + std::to_string(i)}
+                        }));
+                        ++i;
+                    }
+
+                    // add other remaining elements
+                    while (i < target.size())
+                    {
+                        result.push_back(
+                        {
+                            {"op", "add"},
+                            {"path", path + "/" + std::to_string(i)},
+                            {"value", target[i]}
+                        });
+                        ++i;
+                    }
+
+                    break;
+                }
+
+                case value_t::object:
+                {
+                    // first pass: traverse this object's elements
+                    for (auto it = source.begin(); it != source.end(); ++it)
+                    {
+                        // escape the key name to be used in a JSON patch
+                        const auto key = json_pointer::escape(it.key());
+
+                        if (target.find(it.key()) != target.end())
+                        {
+                            // recursive call to compare object values at key it
+                            auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key);
+                            result.insert(result.end(), temp_diff.begin(), temp_diff.end());
+                        }
+                        else
+                        {
+                            // found a key that is not in o -> remove it
+                            result.push_back(object(
+                            {
+                                {"op", "remove"},
+                                {"path", path + "/" + key}
+                            }));
+                        }
+                    }
+
+                    // second pass: traverse other object's elements
+                    for (auto it = target.begin(); it != target.end(); ++it)
+                    {
+                        if (source.find(it.key()) == source.end())
+                        {
+                            // found a key that is not in this -> add it
+                            const auto key = json_pointer::escape(it.key());
+                            result.push_back(
+                            {
+                                {"op", "add"},
+                                {"path", path + "/" + key},
+                                {"value", it.value()}
+                            });
+                        }
+                    }
+
+                    break;
+                }
+
+                default:
+                {
+                    // both primitive type: replace value
+                    result.push_back(
+                    {
+                        {"op", "replace"},
+                        {"path", path},
+                        {"value", target}
+                    });
+                    break;
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /// @}
+};
+
+
+/////////////
+// presets //
+/////////////
+
+/*!
+@brief default JSON class
+
+This type is the default specialization of the @ref basic_json class which
+uses the standard template types.
+
+@since version 1.0.0
+*/
+using json = basic_json<>;
+}
+
+
+///////////////////////
+// nonmember support //
+///////////////////////
+
+// specialization of std::swap, and std::hash
+namespace std
+{
+/*!
+@brief exchanges the values of two JSON objects
+
+@since version 1.0.0
+*/
+template <>
+inline void swap(nlohmann::json& j1,
+                 nlohmann::json& j2) noexcept(
+                     is_nothrow_move_constructible<nlohmann::json>::value and
+                     is_nothrow_move_assignable<nlohmann::json>::value
+                 )
+{
+    j1.swap(j2);
+}
+
+/// hash value for JSON objects
+template <>
+struct hash<nlohmann::json>
+{
+    /*!
+    @brief return a hash value for a JSON object
+
+    @since version 1.0.0
+    */
+    std::size_t operator()(const nlohmann::json& j) const
+    {
+        // a naive hashing via the string representation
+        const auto& h = hash<nlohmann::json::string_t>();
+        return h(j.dump());
+    }
+};
+}
+
+/*!
+@brief user-defined string literal for JSON values
+
+This operator implements a user-defined string literal for JSON objects. It
+can be used by adding `"_json"` to a string literal and returns a JSON object
+if no parse error occurred.
+
+@param[in] s  a string representation of a JSON object
+@return a JSON object
+
+@since version 1.0.0
+*/
+inline nlohmann::json operator "" _json(const char* s, std::size_t)
+{
+    return nlohmann::json::parse(reinterpret_cast<const nlohmann::json::string_t::value_type*>(s));
+}
+
+/*!
+@brief user-defined string literal for JSON pointer
+
+This operator implements a user-defined string literal for JSON Pointers. It
+can be used by adding `"_json"` to a string literal and returns a JSON pointer
+object if no parse error occurred.
+
+@param[in] s  a string representation of a JSON Pointer
+@return a JSON pointer object
+
+@since version 2.0.0
+*/
+inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t)
+{
+    return nlohmann::json::json_pointer(s);
+}
+
+// restore GCC/clang diagnostic settings
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #pragma GCC diagnostic pop
+#endif
+
+#endif
diff --git a/ext/offbase/README.md b/ext/offbase/README.md
deleted file mode 100644
index 6668b878..00000000
--- a/ext/offbase/README.md
+++ /dev/null
@@ -1,59 +0,0 @@
-A super-minimal in-filesystem persistent JSON object
-======
-
-[We](https://www.zerotier.com/) like minimalism.
-
-Offbase is an extension of the excellent [nlohmann/json](https://github.com/nlohmann/json) C++11 JSON class that adds simple object persistence to/from the filesystem. Objects are stored into a directory hierarchy in fully "expanded" form with each field/value being represented by a separate file.
-
-Features:
-
- - Very easy to use
- - Minimal!
-   - Easy to understand and maintain
-	 - Trivial to implement in other languages
-	 - No dependencies beyond standard libraries
-	 - Small code footprint in both source and binary form
-	 - Easy to port to other platforms
- - Exactly reproduces JSON object hierarchies including all JSON type information
- - Database can be explored from the shell, browsed in a web browser or file explorer, scanned with `find` and `grep`, etc.
- - Database can be backed up, restored, versioned, etc. with tools like `git`, `rsync`, `duplicity`, etc.
- - Alien files like `.git` or `.DS_Store` are harmlessly ignored if present
- - Saving only changes what's changed to reduce I/O overhead and SSD wear
-
-Limitations and shortcomings:
-
- - This creates a lot of tiny files, which is inefficient on some filesystems and might run into inode limits in extreme cases. For data sets with more than, say, a million items we recommend a filesystem like `btrfs` or `reiserfs`. Things like [redisfs](https://steve.fi/Software/redisfs/) are also worth exploring. On Linux another alternative is to put the database into `/dev/shm` (RAM disk) and then regularly back it up with `duplicity` or similar.
- - The whole JSON object is held in memory *twice* for diffing purposes.
- - Diffing traverses the whole tree and then updates the shadow copy, which makes `commit()` slow for huge data sets. This is not suitable for "big" data where "big" here is probably more than a few hundred megabytes.
- - Recursion is used, so if you have object hierarchies that are incredibly deep (hundreds or more) it might be possible to overflow your stack and crash your app.
- - This is not thread safe and must be guarded by a mutex if used in a threaded app.
-
-Caveats:
-
- - Key names are escaped for safety in the filesystem, but we still don't recommend allowing external users to set just anything into your JSON store. See the point about recursion under limitations.
-
-Future:
-
- - It would not be too hard to tie this into a filesystem change monitoring API and automatically read changes from disk if they are detected. This would allow the database to be edited "live" in the filesystem.
-   - In theory this could provide replication or clustering through distributed filesystems, file syncing, or things like [Amazon Elastic Filesystem](https://aws.amazon.com/efs/).
- - Recursion could be factored out to get rid of any object hierarchy depth constraints.
- - Mutexes could be integrated somehow to allow for finer grained locking in multithreaded apps.
- - Diffing and selective updates could be made more memory and CPU efficient using hashes, etc.
-
-## How to Use
-
-The `offbase` class just extends [nlohmann::json](https://github.com/nlohmann/json) and gives you a JSON object. Take care to make sure you don't change the type of the 'root' object represented by the 'offbase' instance from JSON 'object'. Anything under it can of course be any JSON type, including any object.
-
-Just put data into the object and then periodically call `commit()` to persist changes to disk. The `commit()` method diffs the current contents of the object with what it knows to have been previously persisted to disk and modifies the representation on disk to match. This can be done after writes or periodically in a background thread.
-
-See comments in `offbase.hpp` for full documentation including details about error handling, etc.
-
-## Persistence format
-
-The base object represented by the `offbase` instance is persisted into a directory hierarchy under its base path. Files and directories are named according to a simple convention of `keyname.typecode` where `keyname` is an escaped key name (or hex array index in the case of arrays) and `typecode` is a single character indicating whether the item is a JSON value, array, or object.
-
- - `*.V`: JSON values (actual value type is inferred during JSON parse)
- - `*.O`: JSON objects (these are subdirectories)
- - `*.A`: JSON arrays (also subdirectories containing items by hex array index)
-
-There are in theory simpler ways to represent JSON in a filesystem, such as the "flattened" JSON "pointer" format, but this has the disadvantage of not disambiguating objects vs. arrays. Offbase's persistence format is designed to perfectly reproduce the exact same JSON tree on load as was most recently committed.
diff --git a/ext/offbase/json/LICENSE.MIT b/ext/offbase/json/LICENSE.MIT
deleted file mode 100644
index e2ac4891..00000000
--- a/ext/offbase/json/LICENSE.MIT
+++ /dev/null
@@ -1,22 +0,0 @@
-The library is licensed under the MIT License 
-<http://opensource.org/licenses/MIT>:
-
-Copyright (c) 2013-2016 Niels Lohmann
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
diff --git a/ext/offbase/json/README.md b/ext/offbase/json/README.md
deleted file mode 100644
index c0bb61b1..00000000
--- a/ext/offbase/json/README.md
+++ /dev/null
@@ -1,511 +0,0 @@
-[![JSON for Modern C++](https://raw.githubusercontent.com/nlohmann/json/master/doc/json.gif)](https://github.com/nlohmann/json/releases)
-
-[![Build Status](https://travis-ci.org/nlohmann/json.svg?branch=master)](https://travis-ci.org/nlohmann/json)
-[![Build Status](https://ci.appveyor.com/api/projects/status/1acb366xfyg3qybk?svg=true)](https://ci.appveyor.com/project/nlohmann/json)
-[![Coverage Status](https://img.shields.io/coveralls/nlohmann/json.svg)](https://coveralls.io/r/nlohmann/json)
-[![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
-[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/p5o4znPnGHJpDVqN)
-[![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](http://nlohmann.github.io/json)
-[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
-[![Github Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
-[![Github Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](http://github.com/nlohmann/json/issues)
-
-## Design goals
-
-There are myriads of [JSON](http://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
-
-- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you know, what I mean.
-
-- **Trivial integration**. Our whole code consists of a single header file [`json.hpp`](https://github.com/nlohmann/json/blob/develop/src/json.hpp). That's it. No library, no subproject, no dependencies, no complex build system. The class is written in vanilla C++11. All in all, everything should require no adjustment of your compiler flags or project settings.
-
-- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/blob/master/test/src/unit.cpp) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) that there are no memory leaks.
-
-Other aspects were not so important to us:
-
-- **Memory efficiency**. Each JSON object has an overhead of one pointer (the maximal size of a union) and one enumeration element (1 byte). The default generalization uses the following C++ data types: `std::string` for strings, `int64_t`, `uint64_t` or `double` for numbers, `std::map` for objects, `std::vector` for arrays, and `bool` for Booleans. However, you can template the generalized class `basic_json` to your needs.
-
-- **Speed**. We currently implement the parser as naive [recursive descent parser](http://en.wikipedia.org/wiki/Recursive_descent_parser) with hand coded string handling. It is fast enough, but a [LALR-parser](http://en.wikipedia.org/wiki/LALR_parser) may be even faster (but would consist of more files which makes the integration harder).
-
-See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.github/CONTRIBUTING.md#please-dont) for more information.
-
-
-## Integration
-
-The single required source, file `json.hpp` is in the `src` directory or [released here](https://github.com/nlohmann/json/releases). All you need to do is add
-
-```cpp
-#include "json.hpp"
-
-// for convenience
-using json = nlohmann::json;
-```
-
-to the files you want to use JSON objects. That's it. Do not forget to set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).
-
-:beer: If you are using OS X and [Homebrew](http://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann_json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann_json --HEAD`.
-
-
-## Examples
-
-Here are some examples to give you an idea how to use the class.
-
-Assume you want to create the JSON object
-
-```json
-{
-  "pi": 3.141,
-  "happy": true,
-  "name": "Niels",
-  "nothing": null,
-  "answer": {
-    "everything": 42
-  },
-  "list": [1, 0, 2],
-  "object": {
-    "currency": "USD",
-    "value": 42.99
-  }
-}
-```
-
-With the JSON class, you could write:
-
-```cpp
-// create an empty structure (null)
-json j;
-
-// add a number that is stored as double (note the implicit conversion of j to an object)
-j["pi"] = 3.141;
-
-// add a Boolean that is stored as bool
-j["happy"] = true;
-
-// add a string that is stored as std::string
-j["name"] = "Niels";
-
-// add another null object by passing nullptr
-j["nothing"] = nullptr;
-
-// add an object inside the object
-j["answer"]["everything"] = 42;
-
-// add an array that is stored as std::vector (using an initializer list)
-j["list"] = { 1, 0, 2 };
-
-// add another object (using an initializer list of pairs)
-j["object"] = { {"currency", "USD"}, {"value", 42.99} };
-
-// instead, you could also write (which looks very similar to the JSON above)
-json j2 = {
-  {"pi", 3.141},
-  {"happy", true},
-  {"name", "Niels"},
-  {"nothing", nullptr},
-  {"answer", {
-    {"everything", 42}
-  }},
-  {"list", {1, 0, 2}},
-  {"object", {
-    {"currency", "USD"},
-    {"value", 42.99}
-  }}
-};
-```
-
-Note that in all these cases, you never need to "tell" the compiler which JSON value you want to use. If you want to be explicit or express some edge cases, the functions `json::array` and `json::object` will help:
-
-```cpp
-// a way to express the empty array []
-json empty_array_explicit = json::array();
-
-// ways to express the empty object {}
-json empty_object_implicit = json({});
-json empty_object_explicit = json::object();
-
-// a way to express an _array_ of key/value pairs [["currency", "USD"], ["value", 42.99]]
-json array_not_object = { json::array({"currency", "USD"}), json::array({"value", 42.99}) };
-```
-
-
-### Serialization / Deserialization
-
-You can create an object (deserialization) by appending `_json` to a string literal:
-
-```cpp
-// create object from string literal
-json j = "{ \"happy\": true, \"pi\": 3.141 }"_json;
-
-// or even nicer with a raw string literal
-auto j2 = R"(
-  {
-    "happy": true,
-    "pi": 3.141
-  }
-)"_json;
-
-// or explicitly
-auto j3 = json::parse("{ \"happy\": true, \"pi\": 3.141 }");
-```
-
-You can also get a string representation (serialize):
-
-```cpp
-// explicit conversion to string
-std::string s = j.dump();    // {\"happy\":true,\"pi\":3.141}
-
-// serialization with pretty printing
-// pass in the amount of spaces to indent
-std::cout << j.dump(4) << std::endl;
-// {
-//     "happy": true,
-//     "pi": 3.141
-// }
-```
-
-You can also use streams to serialize and deserialize:
-
-```cpp
-// deserialize from standard input
-json j;
-std::cin >> j;
-
-// serialize to standard output
-std::cout << j;
-
-// the setw manipulator was overloaded to set the indentation for pretty printing
-std::cout << std::setw(4) << j << std::endl;
-```
-
-These operators work for any subclasses of `std::istream` or `std::ostream`.
-
-Please note that setting the exception bit for `failbit` is inappropriate for this use case. It will result in program termination due to the `noexcept` specifier in use.
-
-
-### STL-like access
-
-We designed the JSON class to behave just like an STL container. In fact, it satisfies the [**ReversibleContainer**](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) requirement.
-
-```cpp
-// create an array using push_back
-json j;
-j.push_back("foo");
-j.push_back(1);
-j.push_back(true);
-
-// iterate the array
-for (json::iterator it = j.begin(); it != j.end(); ++it) {
-  std::cout << *it << '\n';
-}
-
-// range-based for
-for (auto& element : j) {
-  std::cout << element << '\n';
-}
-
-// getter/setter
-const std::string tmp = j[0];
-j[1] = 42;
-bool foo = j.at(2);
-
-// other stuff
-j.size();     // 3 entries
-j.empty();    // false
-j.type();     // json::value_t::array
-j.clear();    // the array is empty again
-
-// convenience type checkers
-j.is_null();
-j.is_boolean();
-j.is_number();
-j.is_object();
-j.is_array();
-j.is_string();
-
-// comparison
-j == "[\"foo\", 1, true]"_json;  // true
-
-// create an object
-json o;
-o["foo"] = 23;
-o["bar"] = false;
-o["baz"] = 3.141;
-
-// special iterator member functions for objects
-for (json::iterator it = o.begin(); it != o.end(); ++it) {
-  std::cout << it.key() << " : " << it.value() << "\n";
-}
-
-// find an entry
-if (o.find("foo") != o.end()) {
-  // there is an entry with key "foo"
-}
-
-// or simpler using count()
-int foo_present = o.count("foo"); // 1
-int fob_present = o.count("fob"); // 0
-
-// delete an entry
-o.erase("foo");
-```
-
-
-### Conversion from STL containers
-
-Any sequence container (`std::array`, `std::vector`, `std::deque`, `std::forward_list`, `std::list`) whose values can be used to construct JSON types (e.g., integers, floating point numbers, Booleans, string types, or again STL containers described in this section) can be used to create a JSON array. The same holds for similar associative containers (`std::set`, `std::multiset`, `std::unordered_set`, `std::unordered_multiset`), but in these cases the order of the elements of the array depends how the elements are ordered in the respective STL container.
-
-```cpp
-std::vector<int> c_vector {1, 2, 3, 4};
-json j_vec(c_vector);
-// [1, 2, 3, 4]
-
-std::deque<double> c_deque {1.2, 2.3, 3.4, 5.6};
-json j_deque(c_deque);
-// [1.2, 2.3, 3.4, 5.6]
-
-std::list<bool> c_list {true, true, false, true};
-json j_list(c_list);
-// [true, true, false, true]
-
-std::forward_list<int64_t> c_flist {12345678909876, 23456789098765, 34567890987654, 45678909876543};
-json j_flist(c_flist);
-// [12345678909876, 23456789098765, 34567890987654, 45678909876543]
-
-std::array<unsigned long, 4> c_array {{1, 2, 3, 4}};
-json j_array(c_array);
-// [1, 2, 3, 4]
-
-std::set<std::string> c_set {"one", "two", "three", "four", "one"};
-json j_set(c_set); // only one entry for "one" is used
-// ["four", "one", "three", "two"]
-
-std::unordered_set<std::string> c_uset {"one", "two", "three", "four", "one"};
-json j_uset(c_uset); // only one entry for "one" is used
-// maybe ["two", "three", "four", "one"]
-
-std::multiset<std::string> c_mset {"one", "two", "one", "four"};
-json j_mset(c_mset); // only one entry for "one" is used
-// maybe ["one", "two", "four"]
-
-std::unordered_multiset<std::string> c_umset {"one", "two", "one", "four"};
-json j_umset(c_umset); // both entries for "one" are used
-// maybe ["one", "two", "one", "four"]
-```
-
-Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON types (see examples above) can be used to to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
-
-```cpp
-std::map<std::string, int> c_map { {"one", 1}, {"two", 2}, {"three", 3} };
-json j_map(c_map);
-// {"one": 1, "three": 3, "two": 2 }
-
-std::unordered_map<const char*, double> c_umap { {"one", 1.2}, {"two", 2.3}, {"three", 3.4} };
-json j_umap(c_umap);
-// {"one": 1.2, "two": 2.3, "three": 3.4}
-
-std::multimap<std::string, bool> c_mmap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
-json j_mmap(c_mmap); // only one entry for key "three" is used
-// maybe {"one": true, "two": true, "three": true}
-
-std::unordered_multimap<std::string, bool> c_ummap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
-json j_ummap(c_ummap); // only one entry for key "three" is used
-// maybe {"one": true, "two": true, "three": true}
-```
-
-### JSON Pointer and JSON Patch
-
-The library supports **JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) as alternative means to address structured values. On top of this, **JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) allows to describe differences between two JSON values - effectively allowing patch and diff operations known from Unix.
-
-```cpp
-// a JSON value
-json j_original = R"({
-  "baz": ["one", "two", "three"],
-  "foo": "bar"
-})"_json;
-
-// access members with a JSON pointer (RFC 6901)
-j_original["/baz/1"_json_pointer];
-// "two"
-
-// a JSON patch (RFC 6902)
-json j_patch = R"([
-  { "op": "replace", "path": "/baz", "value": "boo" },
-  { "op": "add", "path": "/hello", "value": ["world"] },
-  { "op": "remove", "path": "/foo"}
-])"_json;
-
-// apply the patch
-json j_result = j_original.patch(j_patch);
-// {
-//    "baz": "boo",
-//    "hello": ["world"]
-// }
-
-// calculate a JSON patch from two JSON values
-json::diff(j_result, j_original);
-// [
-//   { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] },
-//   { "op": "remove","path": "/hello" },
-//   { "op": "add", "path": "/foo", "value": "bar" }
-// ]
-```
-
-
-### Implicit conversions
-
-The type of the JSON object is determined automatically by the expression to store. Likewise, the stored value is implicitly converted.
-
-```cpp
-// strings
-std::string s1 = "Hello, world!";
-json js = s1;
-std::string s2 = js;
-
-// Booleans
-bool b1 = true;
-json jb = b1;
-bool b2 = jb;
-
-// numbers
-int i = 42;
-json jn = i;
-double f = jn;
-
-// etc.
-```
-
-You can also explicitly ask for the value:
-
-```cpp
-std::string vs = js.get<std::string>();
-bool vb = jb.get<bool>();
-int vi = jn.get<int>();
-
-// etc.
-```
-
-
-## Supported compilers
-
-Though it's 2016 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
-
-- GCC 4.9 - 6.0 (and possibly later)
-- Clang 3.4 - 3.9 (and possibly later)
-- Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
-
-I would be happy to learn about other compilers/versions.
-
-Please note:
-
-- GCC 4.8 does not work because of two bugs ([55817](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55817) and [57824](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57824)) in the C++11 support. Note there is a [pull request](https://github.com/nlohmann/json/pull/212) to fix some of the issues.
-- Android defaults to using very old compilers and C++ libraries. To fix this, add the following to your `Application.mk`. This will switch to the LLVM C++ library, the Clang compiler, and enable C++11 and other features disabled by default.
- 
-    ```
-    APP_STL := c++_shared
-    NDK_TOOLCHAIN_VERSION := clang3.6
-    APP_CPPFLAGS += -frtti -fexceptions
-    ```
- 
-    The code compiles successfully with [Android NDK](https://developer.android.com/ndk/index.html?hl=ml), Revision 9 - 11 (and possibly later) and [CrystaX's Android NDK](https://www.crystax.net/en/android/ndk) version 10.
-
-- For GCC running on MinGW or Android SDK, the error `'to_string' is not a member of 'std'` (or similarly, for `strtod`) may occur. Note this is not an issue with the code,  but rather with the compiler itself. On Android, see above to build with a newer environment.  For MinGW, please refer to [this site](http://tehsausage.com/mingw-to-string) and [this discussion](https://github.com/nlohmann/json/issues/136) for information on how to fix this bug. For Android NDK using `APP_STL := gnustl_static`, please refer to [this discussion](https://github.com/nlohmann/json/issues/219).
-
-The following compilers are currently used in continuous integration at [Travis](https://travis-ci.org/nlohmann/json) and [AppVeyor](https://ci.appveyor.com/project/nlohmann/json):
-
-| Compiler        | Operating System             | Version String |
-|-----------------|------------------------------|----------------|
-| GCC 4.9.3       | Ubuntu 14.04.4 LTS           | g++-4.9 (Ubuntu 4.9.3-8ubuntu2~14.04) 4.9.3 |
-| GCC 5.3.0       | Ubuntu 14.04.4 LTS           | g++-5 (Ubuntu 5.3.0-3ubuntu1~14.04) 5.3.0 20151204 |
-| GCC 6.1.1       | Ubuntu 14.04.4 LTS           | g++-6 (Ubuntu 6.1.1-3ubuntu11~14.04.1) 6.1.1 20160511 |
-| Clang 3.8.0     | Ubuntu 14.04.4 LTS           | clang version 3.8.0 (tags/RELEASE_380/final) |
-| Clang Xcode 6.1 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) |
-| Clang Xcode 6.2 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) |
-| Clang Xcode 6.3 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn) |
-| Clang Xcode 6.4 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn) |
-| Clang Xcode 7.1 | Darwin Kernel Version 14.5.0 (OSX 10.10.5) | Apple LLVM version 7.0.0 (clang-700.1.76) |
-| Clang Xcode 7.2 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.0.2 (clang-700.1.81) |
-| Clang Xcode 7.3 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.3.0 (clang-703.0.29) |
-| Clang Xcode 8.0 | Darwin Kernel Version 15.5.0 (OSX 10.11.5) | Apple LLVM version 8.0.0 (clang-800.0.24.1) |
-| Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25123.0 | 
-
-
-## License
-
-<img align="right" src="http://opensource.org/trademarks/opensource/OSI-Approved-License-100x137.png">
-
-The class is licensed under the [MIT License](http://opensource.org/licenses/MIT):
-
-Copyright &copy; 2013-2016 [Niels Lohmann](http://nlohmann.me)
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-
-## Thanks
-
-I deeply appreciate the help of the following people.
-
-- [Teemperor](https://github.com/Teemperor) implemented CMake support and lcov integration, realized escape and Unicode handling in the string parser, and fixed the JSON serialization.
-- [elliotgoodrich](https://github.com/elliotgoodrich) fixed an issue with double deletion in the iterator classes.
-- [kirkshoop](https://github.com/kirkshoop) made the iterators of the class composable to other libraries.
-- [wancw](https://github.com/wanwc) fixed a bug that hindered the class to compile with Clang.
-- Tomas Åblad found a bug in the iterator implementation.
-- [Joshua C. Randall](https://github.com/jrandall) fixed a bug in the floating-point serialization.
-- [Aaron Burghardt](https://github.com/aburgh) implemented code to parse streams incrementally. Furthermore, he greatly improved the parser class by allowing the definition of a filter function to discard undesired elements while parsing.
-- [Daniel Kopeček](https://github.com/dkopecek) fixed a bug in the compilation with GCC 5.0.
-- [Florian Weber](https://github.com/Florianjw) fixed a bug in and improved the performance of the comparison operators.
-- [Eric Cornelius](https://github.com/EricMCornelius) pointed out a bug in the handling with NaN and infinity values. He also improved the performance of the string escaping.
-- [易思龙](https://github.com/likebeta) implemented a conversion from anonymous enums.
-- [kepkin](https://github.com/kepkin) patiently pushed forward the support for Microsoft Visual studio.
-- [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators and helped with numerous hints and improvements.
-- [Caio Luppi](https://github.com/caiovlp) fixed a bug in the Unicode handling.
-- [dariomt](https://github.com/dariomt) fixed some typos in the examples.
-- [Daniel Frey](https://github.com/d-frey) cleaned up some pointers and implemented exception-safe memory allocation.
-- [Colin Hirsch](https://github.com/ColinH) took care of a small namespace issue.
-- [Huu Nguyen](https://github.com/whoshuu) correct a variable name in the documentation.
-- [Silverweed](https://github.com/silverweed) overloaded `parse()` to accept an rvalue reference.
-- [dariomt](https://github.com/dariomt) fixed a subtlety in MSVC type support and implemented the `get_ref()` function to get a reference to stored values.
-- [ZahlGraf](https://github.com/ZahlGraf) added a workaround that allows compilation using Android NDK.
-- [whackashoe](https://github.com/whackashoe) replaced a function that was marked as unsafe by Visual Studio.
-- [406345](https://github.com/406345) fixed two small warnings.
-- [Glen Fernandes](https://github.com/glenfe) noted a potential portability problem in the `has_mapped_type` function.
-- [Corbin Hughes](https://github.com/nibroc) fixed some typos in the contribution guidelines.
-- [twelsby](https://github.com/twelsby) fixed the array subscript operator, an issue that failed the MSVC build, and floating-point parsing/dumping. He further added support for unsigned integer numbers and implemented better roundtrip support for parsed numbers.
-- [Volker Diels-Grabsch](https://github.com/vog) fixed a link in the README file.
-- [msm-](https://github.com/msm-) added support for american fuzzy lop. 
-- [Annihil](https://github.com/Annihil) fixed an example in the README file.
-- [Themercee](https://github.com/Themercee) noted a wrong URL in the README file.
-- [Lv Zheng](https://github.com/lv-zheng) fixed a namespace issue with `int64_t` and `uint64_t`.
-- [abc100m](https://github.com/abc100m) analyzed the issues with GCC 4.8 and proposed a [partial solution](https://github.com/nlohmann/json/pull/212).
-- [zewt](https://github.com/zewt) added useful notes to the README file about Android.
-- [Róbert Márki](https://github.com/robertmrk) added a fix to use move iterators and improved the integration via CMake.
-- [Chris Kitching](https://github.com/ChrisKitching) cleaned up the CMake files.
-- [Tom Needham](https://github.com/06needhamt) fixed a subtle bug with MSVC 2015 which was also proposed by [Michael K.](https://github.com/Epidal).
-- [Mário Feroldi](https://github.com/thelostt) fixed a small typo.
-- [duncanwerner](https://github.com/duncanwerner) found a really embarrassing performance regression in the 2.0.0 release.
-- [Damien](https://github.com/dtoma) fixed one of the last conversion warnings.
-
-Thanks a lot for helping out!
-
-
-## Notes
-
-- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](http://en.cppreference.com/w/cpp/error/assert).
-- As the exact type of a number is not defined in the [JSON specification](http://rfc7159.net/rfc7159), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
-
-
-## Execute unit tests
-
-To compile and run the tests, you need to execute
-
-```sh
-$ make
-$ ./json_unit "*"
-
-===============================================================================
-All tests passed (8905012 assertions in 32 test cases)
-```
-
-For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).
diff --git a/ext/offbase/json/json.hpp b/ext/offbase/json/json.hpp
deleted file mode 100644
index 878fb899..00000000
--- a/ext/offbase/json/json.hpp
+++ /dev/null
@@ -1,10435 +0,0 @@
-/*
-    __ _____ _____ _____
- __|  |   __|     |   | |  JSON for Modern C++
-|  |  |__   |  |  | | | |  version 2.0.2
-|_____|_____|_____|_|___|  https://github.com/nlohmann/json
-
-Licensed under the MIT License <http://opensource.org/licenses/MIT>.
-Copyright (c) 2013-2016 Niels Lohmann <http://nlohmann.me>.
-
-Permission is hereby  granted, free of charge, to any  person obtaining a copy
-of this software and associated  documentation files (the "Software"), to deal
-in the Software  without restriction, including without  limitation the rights
-to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
-copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
-IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
-FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
-AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
-LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
-*/
-
-#ifndef NLOHMANN_JSON_HPP
-#define NLOHMANN_JSON_HPP
-
-#include <algorithm>
-#include <array>
-#include <cassert>
-#include <ciso646>
-#include <cmath>
-#include <cstddef>
-#include <cstdint>
-#include <cstdlib>
-#include <functional>
-#include <initializer_list>
-#include <iomanip>
-#include <iostream>
-#include <iterator>
-#include <limits>
-#include <locale>
-#include <map>
-#include <memory>
-#include <numeric>
-#include <sstream>
-#include <stdexcept>
-#include <string>
-#include <type_traits>
-#include <utility>
-#include <vector>
-
-// exclude unsupported compilers
-#if defined(__clang__)
-    #define CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
-    #if CLANG_VERSION < 30400
-        #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
-    #endif
-#elif defined(__GNUC__)
-    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
-    #if GCC_VERSION < 40900
-        #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
-    #endif
-#endif
-
-// disable float-equal warnings on GCC/clang
-#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-    #pragma GCC diagnostic push
-    #pragma GCC diagnostic ignored "-Wfloat-equal"
-#endif
-
-/*!
-@brief namespace for Niels Lohmann
-@see https://github.com/nlohmann
-@since version 1.0.0
-*/
-namespace nlohmann
-{
-
-
-/*!
-@brief unnamed namespace with internal helper functions
-@since version 1.0.0
-*/
-namespace
-{
-/*!
-@brief Helper to determine whether there's a key_type for T.
-
-Thus helper is used to tell associative containers apart from other containers
-such as sequence containers. For instance, `std::map` passes the test as it
-contains a `mapped_type`, whereas `std::vector` fails the test.
-
-@sa http://stackoverflow.com/a/7728728/266378
-@since version 1.0.0
-*/
-template<typename T>
-struct has_mapped_type
-{
-  private:
-    template<typename C> static char test(typename C::mapped_type*);
-    template<typename C> static char (&test(...))[2];
-  public:
-    static constexpr bool value = sizeof(test<T>(0)) == 1;
-};
-
-/*!
-@brief helper class to create locales with decimal point
-
-This struct is used a default locale during the JSON serialization. JSON
-requires the decimal point to be `.`, so this function overloads the
-`do_decimal_point()` function to return `.`. This function is called by
-float-to-string conversions to retrieve the decimal separator between integer
-and fractional parts.
-
-@sa https://github.com/nlohmann/json/issues/51#issuecomment-86869315
-@since version 2.0.0
-*/
-struct DecimalSeparator : std::numpunct<char>
-{
-    char do_decimal_point() const
-    {
-        return '.';
-    }
-};
-
-}
-
-/*!
-@brief a class to store JSON values
-
-@tparam ObjectType type for JSON objects (`std::map` by default; will be used
-in @ref object_t)
-@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
-in @ref array_t)
-@tparam StringType type for JSON strings and object keys (`std::string` by
-default; will be used in @ref string_t)
-@tparam BooleanType type for JSON booleans (`bool` by default; will be used
-in @ref boolean_t)
-@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
-default; will be used in @ref number_integer_t)
-@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
-`uint64_t` by default; will be used in @ref number_unsigned_t)
-@tparam NumberFloatType type for JSON floating-point numbers (`double` by
-default; will be used in @ref number_float_t)
-@tparam AllocatorType type of the allocator to use (`std::allocator` by
-default)
-
-@requirement The class satisfies the following concept requirements:
-- Basic
- - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
-   JSON values can be default constructed. The result will be a JSON null value.
- - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
-   A JSON value can be constructed from an rvalue argument.
- - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
-   A JSON value can be copy-constructed from an lvalue expression.
- - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
-   A JSON value van be assigned from an rvalue argument.
- - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
-   A JSON value can be copy-assigned from an lvalue expression.
- - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
-   JSON values can be destructed.
-- Layout
- - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
-   JSON values have
-   [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
-   All non-static data members are private and standard layout types, the class
-   has no virtual functions or (virtual) base classes.
-- Library-wide
- - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
-   JSON values can be compared with `==`, see @ref
-   operator==(const_reference,const_reference).
- - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
-   JSON values can be compared with `<`, see @ref
-   operator<(const_reference,const_reference).
- - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
-   Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
-   other compatible types, using unqualified function call @ref swap().
- - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
-   JSON values can be compared against `std::nullptr_t` objects which are used
-   to model the `null` value.
-- Container
- - [Container](http://en.cppreference.com/w/cpp/concept/Container):
-   JSON values can be used like STL containers and provide iterator access.
- - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
-   JSON values can be used like STL containers and provide reverse iterator
-   access.
-
-@invariant The member variables @a m_value and @a m_type have the following
-relationship:
-- If `m_type == value_t::object`, then `m_value.object != nullptr`.
-- If `m_type == value_t::array`, then `m_value.array != nullptr`.
-- If `m_type == value_t::string`, then `m_value.string != nullptr`.
-The invariants are checked by member function assert_invariant().
-
-@internal
-@note ObjectType trick from http://stackoverflow.com/a/9860911
-@endinternal
-
-@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
-Format](http://rfc7159.net/rfc7159)
-
-@since version 1.0.0
-
-@nosubgrouping
-*/
-template <
-    template<typename U, typename V, typename... Args> class ObjectType = std::map,
-    template<typename U, typename... Args> class ArrayType = std::vector,
-    class StringType = std::string,
-    class BooleanType = bool,
-    class NumberIntegerType = std::int64_t,
-    class NumberUnsignedType = std::uint64_t,
-    class NumberFloatType = double,
-    template<typename U> class AllocatorType = std::allocator
-    >
-class basic_json
-{
-  private:
-    /// workaround type for MSVC
-    using basic_json_t = basic_json<ObjectType, ArrayType, StringType,
-          BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType,
-          AllocatorType>;
-
-  public:
-    // forward declarations
-    template<typename Base> class json_reverse_iterator;
-    class json_pointer;
-
-    /////////////////////
-    // container types //
-    /////////////////////
-
-    /// @name container types
-    /// The canonic container types to use @ref basic_json like any other STL
-    /// container.
-    /// @{
-
-    /// the type of elements in a basic_json container
-    using value_type = basic_json;
-
-    /// the type of an element reference
-    using reference = value_type&;
-    /// the type of an element const reference
-    using const_reference = const value_type&;
-
-    /// a type to represent differences between iterators
-    using difference_type = std::ptrdiff_t;
-    /// a type to represent container sizes
-    using size_type = std::size_t;
-
-    /// the allocator type
-    using allocator_type = AllocatorType<basic_json>;
-
-    /// the type of an element pointer
-    using pointer = typename std::allocator_traits<allocator_type>::pointer;
-    /// the type of an element const pointer
-    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
-
-    /// an iterator for a basic_json container
-    class iterator;
-    /// a const iterator for a basic_json container
-    class const_iterator;
-    /// a reverse iterator for a basic_json container
-    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
-    /// a const reverse iterator for a basic_json container
-    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;
-
-    /// @}
-
-
-    /*!
-    @brief returns the allocator associated with the container
-    */
-    static allocator_type get_allocator()
-    {
-        return allocator_type();
-    }
-
-
-    ///////////////////////////
-    // JSON value data types //
-    ///////////////////////////
-
-    /// @name JSON value data types
-    /// The data types to store a JSON value. These types are derived from
-    /// the template arguments passed to class @ref basic_json.
-    /// @{
-
-    /*!
-    @brief a type for an object
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
-    > An object is an unordered collection of zero or more name/value pairs,
-    > where a name is a string and a value is a string, number, boolean, null,
-    > object, or array.
-
-    To store objects in C++, a type is defined by the template parameters
-    described below.
-
-    @tparam ObjectType  the container to store objects (e.g., `std::map` or
-    `std::unordered_map`)
-    @tparam StringType the type of the keys or names (e.g., `std::string`).
-    The comparison function `std::less<StringType>` is used to order elements
-    inside the container.
-    @tparam AllocatorType the allocator to use for objects (e.g.,
-    `std::allocator`)
-
-    #### Default type
-
-    With the default values for @a ObjectType (`std::map`), @a StringType
-    (`std::string`), and @a AllocatorType (`std::allocator`), the default
-    value for @a object_t is:
-
-    @code {.cpp}
-    std::map<
-      std::string, // key_type
-      basic_json, // value_type
-      std::less<std::string>, // key_compare
-      std::allocator<std::pair<const std::string, basic_json>> // allocator_type
-    >
-    @endcode
-
-    #### Behavior
-
-    The choice of @a object_t influences the behavior of the JSON class. With
-    the default type, objects have the following behavior:
-
-    - When all names are unique, objects will be interoperable in the sense
-      that all software implementations receiving that object will agree on
-      the name-value mappings.
-    - When the names within an object are not unique, later stored name/value
-      pairs overwrite previously stored name/value pairs, leaving the used
-      names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will
-      be treated as equal and both stored as `{"key": 1}`.
-    - Internally, name/value pairs are stored in lexicographical order of the
-      names. Objects will also be serialized (see @ref dump) in this order.
-      For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored
-      and serialized as `{"a": 2, "b": 1}`.
-    - When comparing objects, the order of the name/value pairs is irrelevant.
-      This makes objects interoperable in the sense that they will not be
-      affected by these differences. For instance, `{"b": 1, "a": 2}` and
-      `{"a": 2, "b": 1}` will be treated as equal.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the maximum depth of nesting.
-
-    In this class, the object's limit of nesting is not constraint explicitly.
-    However, a maximum depth of nesting may be introduced by the compiler or
-    runtime environment. A theoretical limit can be queried by calling the
-    @ref max_size function of a JSON object.
-
-    #### Storage
-
-    Objects are stored as pointers in a @ref basic_json type. That is, for any
-    access to object values, a pointer of type `object_t*` must be
-    dereferenced.
-
-    @sa @ref array_t -- type for an array value
-
-    @since version 1.0.0
-
-    @note The order name/value pairs are added to the object is *not*
-    preserved by the library. Therefore, iterating an object may return
-    name/value pairs in a different order than they were originally stored. In
-    fact, keys will be traversed in alphabetical order as `std::map` with
-    `std::less` is used by default. Please note this behavior conforms to [RFC
-    7159](http://rfc7159.net/rfc7159), because any order implements the
-    specified "unordered" nature of JSON objects.
-    */
-    using object_t = ObjectType<StringType,
-          basic_json,
-          std::less<StringType>,
-          AllocatorType<std::pair<const StringType,
-          basic_json>>>;
-
-    /*!
-    @brief a type for an array
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
-    > An array is an ordered sequence of zero or more values.
-
-    To store objects in C++, a type is defined by the template parameters
-    explained below.
-
-    @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
-    `std::list`)
-    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
-
-    #### Default type
-
-    With the default values for @a ArrayType (`std::vector`) and @a
-    AllocatorType (`std::allocator`), the default value for @a array_t is:
-
-    @code {.cpp}
-    std::vector<
-      basic_json, // value_type
-      std::allocator<basic_json> // allocator_type
-    >
-    @endcode
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the maximum depth of nesting.
-
-    In this class, the array's limit of nesting is not constraint explicitly.
-    However, a maximum depth of nesting may be introduced by the compiler or
-    runtime environment. A theoretical limit can be queried by calling the
-    @ref max_size function of a JSON array.
-
-    #### Storage
-
-    Arrays are stored as pointers in a @ref basic_json type. That is, for any
-    access to array values, a pointer of type `array_t*` must be dereferenced.
-
-    @sa @ref object_t -- type for an object value
-
-    @since version 1.0.0
-    */
-    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
-
-    /*!
-    @brief a type for a string
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
-    > A string is a sequence of zero or more Unicode characters.
-
-    To store objects in C++, a type is defined by the template parameter
-    described below. Unicode values are split by the JSON class into
-    byte-sized characters during deserialization.
-
-    @tparam StringType  the container to store strings (e.g., `std::string`).
-    Note this container is used for keys/names in objects, see @ref object_t.
-
-    #### Default type
-
-    With the default values for @a StringType (`std::string`), the default
-    value for @a string_t is:
-
-    @code {.cpp}
-    std::string
-    @endcode
-
-    #### String comparison
-
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
-    > Software implementations are typically required to test names of object
-    > members for equality. Implementations that transform the textual
-    > representation into sequences of Unicode code units and then perform the
-    > comparison numerically, code unit by code unit, are interoperable in the
-    > sense that implementations will agree in all cases on equality or
-    > inequality of two strings. For example, implementations that compare
-    > strings with escaped characters unconverted may incorrectly find that
-    > `"a\\b"` and `"a\u005Cb"` are not equal.
-
-    This implementation is interoperable as it does compare strings code unit
-    by code unit.
-
-    #### Storage
-
-    String values are stored as pointers in a @ref basic_json type. That is,
-    for any access to string values, a pointer of type `string_t*` must be
-    dereferenced.
-
-    @since version 1.0.0
-    */
-    using string_t = StringType;
-
-    /*!
-    @brief a type for a boolean
-
-    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
-    type which differentiates the two literals `true` and `false`.
-
-    To store objects in C++, a type is defined by the template parameter @a
-    BooleanType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a BooleanType (`bool`), the default value for
-    @a boolean_t is:
-
-    @code {.cpp}
-    bool
-    @endcode
-
-    #### Storage
-
-    Boolean values are stored directly inside a @ref basic_json type.
-
-    @since version 1.0.0
-    */
-    using boolean_t = BooleanType;
-
-    /*!
-    @brief a type for a number (integer)
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
-
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
-
-    To store integer numbers in C++, a type is defined by the template
-    parameter @a NumberIntegerType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a NumberIntegerType (`int64_t`), the default
-    value for @a number_integer_t is:
-
-    @code {.cpp}
-    int64_t
-    @endcode
-
-    #### Default behavior
-
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in integer literals lead to an interpretation as octal
-      number. Internally, the value will be stored as decimal number. For
-      instance, the C++ integer literal `010` will be serialized to `8`.
-      During deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the range and precision of numbers.
-
-    When the default type is used, the maximal integer number that can be
-    stored is `9223372036854775807` (INT64_MAX) and the minimal integer number
-    that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers
-    that are out of range will yield over/underflow when used in a
-    constructor. During deserialization, too large or small integer numbers
-    will be automatically be stored as @ref number_unsigned_t or @ref
-    number_float_t.
-
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
-    > Note that when such software is used, numbers that are integers and are
-    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
-    > that implementations will agree exactly on their numeric values.
-
-    As this range is a subrange of the exactly supported range [INT64_MIN,
-    INT64_MAX], this class's integer type is interoperable.
-
-    #### Storage
-
-    Integer number values are stored directly inside a @ref basic_json type.
-
-    @sa @ref number_float_t -- type for number values (floating-point)
-
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
-
-    @since version 1.0.0
-    */
-    using number_integer_t = NumberIntegerType;
-
-    /*!
-    @brief a type for a number (unsigned)
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
-
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
-
-    To store unsigned integer numbers in C++, a type is defined by the
-    template parameter @a NumberUnsignedType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a NumberUnsignedType (`uint64_t`), the
-    default value for @a number_unsigned_t is:
-
-    @code {.cpp}
-    uint64_t
-    @endcode
-
-    #### Default behavior
-
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in integer literals lead to an interpretation as octal
-      number. Internally, the value will be stored as decimal number. For
-      instance, the C++ integer literal `010` will be serialized to `8`.
-      During deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the range and precision of numbers.
-
-    When the default type is used, the maximal integer number that can be
-    stored is `18446744073709551615` (UINT64_MAX) and the minimal integer
-    number that can be stored is `0`. Integer numbers that are out of range
-    will yield over/underflow when used in a constructor. During
-    deserialization, too large or small integer numbers will be automatically
-    be stored as @ref number_integer_t or @ref number_float_t.
-
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
-    > Note that when such software is used, numbers that are integers and are
-    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
-    > that implementations will agree exactly on their numeric values.
-
-    As this range is a subrange (when considered in conjunction with the
-    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
-    this class's integer type is interoperable.
-
-    #### Storage
-
-    Integer number values are stored directly inside a @ref basic_json type.
-
-    @sa @ref number_float_t -- type for number values (floating-point)
-    @sa @ref number_integer_t -- type for number values (integer)
-
-    @since version 2.0.0
-    */
-    using number_unsigned_t = NumberUnsignedType;
-
-    /*!
-    @brief a type for a number (floating-point)
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
-
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
-
-    To store floating-point numbers in C++, a type is defined by the template
-    parameter @a NumberFloatType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a NumberFloatType (`double`), the default
-    value for @a number_float_t is:
-
-    @code {.cpp}
-    double
-    @endcode
-
-    #### Default behavior
-
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in floating-point literals will be ignored. Internally,
-      the value will be stored as decimal number. For instance, the C++
-      floating-point literal `01.2` will be serialized to `1.2`. During
-      deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
-    > This specification allows implementations to set limits on the range and
-    > precision of numbers accepted. Since software that implements IEEE
-    > 754-2008 binary64 (double precision) numbers is generally available and
-    > widely used, good interoperability can be achieved by implementations
-    > that expect no more precision or range than these provide, in the sense
-    > that implementations will approximate JSON numbers within the expected
-    > precision.
-
-    This implementation does exactly follow this approach, as it uses double
-    precision floating-point numbers. Note values smaller than
-    `-1.79769313486232e+308` and values greater than `1.79769313486232e+308`
-    will be stored as NaN internally and be serialized to `null`.
-
-    #### Storage
-
-    Floating-point number values are stored directly inside a @ref basic_json
-    type.
-
-    @sa @ref number_integer_t -- type for number values (integer)
-
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
-
-    @since version 1.0.0
-    */
-    using number_float_t = NumberFloatType;
-
-    /// @}
-
-
-    ///////////////////////////
-    // JSON type enumeration //
-    ///////////////////////////
-
-    /*!
-    @brief the JSON type enumeration
-
-    This enumeration collects the different JSON types. It is internally used
-    to distinguish the stored values, and the functions @ref is_null(), @ref
-    is_object(), @ref is_array(), @ref is_string(), @ref is_boolean(), @ref
-    is_number() (with @ref is_number_integer(), @ref is_number_unsigned(), and
-    @ref is_number_float()), @ref is_discarded(), @ref is_primitive(), and
-    @ref is_structured() rely on it.
-
-    @note There are three enumeration entries (number_integer,
-    number_unsigned, and number_float), because the library distinguishes
-    these three types for numbers: @ref number_unsigned_t is used for unsigned
-    integers, @ref number_integer_t is used for signed integers, and @ref
-    number_float_t is used for floating-point numbers or to approximate
-    integers which do not fit in the limits of their respective type.
-
-    @sa @ref basic_json(const value_t value_type) -- create a JSON value with
-    the default value for a given type
-
-    @since version 1.0.0
-    */
-    enum class value_t : uint8_t
-    {
-        null,            ///< null value
-        object,          ///< object (unordered set of name/value pairs)
-        array,           ///< array (ordered collection of values)
-        string,          ///< string value
-        boolean,         ///< boolean value
-        number_integer,  ///< number value (signed integer)
-        number_unsigned, ///< number value (unsigned integer)
-        number_float,    ///< number value (floating-point)
-        discarded        ///< discarded by the the parser callback function
-    };
-
-
-  private:
-
-    /// helper for exception-safe object creation
-    template<typename T, typename... Args>
-    static T* create(Args&& ... args)
-    {
-        AllocatorType<T> alloc;
-        auto deleter = [&](T * object)
-        {
-            alloc.deallocate(object, 1);
-        };
-        std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
-        alloc.construct(object.get(), std::forward<Args>(args)...);
-        assert(object.get() != nullptr);
-        return object.release();
-    }
-
-    ////////////////////////
-    // JSON value storage //
-    ////////////////////////
-
-    /*!
-    @brief a JSON value
-
-    The actual storage for a JSON value of the @ref basic_json class. This
-    union combines the different storage types for the JSON value types
-    defined in @ref value_t.
-
-    JSON type | value_t type    | used type
-    --------- | --------------- | ------------------------
-    object    | object          | pointer to @ref object_t
-    array     | array           | pointer to @ref array_t
-    string    | string          | pointer to @ref string_t
-    boolean   | boolean         | @ref boolean_t
-    number    | number_integer  | @ref number_integer_t
-    number    | number_unsigned | @ref number_unsigned_t
-    number    | number_float    | @ref number_float_t
-    null      | null            | *no value is stored*
-
-    @note Variable-length types (objects, arrays, and strings) are stored as
-    pointers. The size of the union should not exceed 64 bits if the default
-    value types are used.
-
-    @since version 1.0.0
-    */
-    union json_value
-    {
-        /// object (stored with pointer to save storage)
-        object_t* object;
-        /// array (stored with pointer to save storage)
-        array_t* array;
-        /// string (stored with pointer to save storage)
-        string_t* string;
-        /// boolean
-        boolean_t boolean;
-        /// number (integer)
-        number_integer_t number_integer;
-        /// number (unsigned integer)
-        number_unsigned_t number_unsigned;
-        /// number (floating-point)
-        number_float_t number_float;
-
-        /// default constructor (for null values)
-        json_value() = default;
-        /// constructor for booleans
-        json_value(boolean_t v) noexcept : boolean(v) {}
-        /// constructor for numbers (integer)
-        json_value(number_integer_t v) noexcept : number_integer(v) {}
-        /// constructor for numbers (unsigned)
-        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
-        /// constructor for numbers (floating-point)
-        json_value(number_float_t v) noexcept : number_float(v) {}
-        /// constructor for empty values of a given type
-        json_value(value_t t)
-        {
-            switch (t)
-            {
-                case value_t::object:
-                {
-                    object = create<object_t>();
-                    break;
-                }
-
-                case value_t::array:
-                {
-                    array = create<array_t>();
-                    break;
-                }
-
-                case value_t::string:
-                {
-                    string = create<string_t>("");
-                    break;
-                }
-
-                case value_t::boolean:
-                {
-                    boolean = boolean_t(false);
-                    break;
-                }
-
-                case value_t::number_integer:
-                {
-                    number_integer = number_integer_t(0);
-                    break;
-                }
-
-                case value_t::number_unsigned:
-                {
-                    number_unsigned = number_unsigned_t(0);
-                    break;
-                }
-
-                case value_t::number_float:
-                {
-                    number_float = number_float_t(0.0);
-                    break;
-                }
-
-                default:
-                {
-                    break;
-                }
-            }
-        }
-
-        /// constructor for strings
-        json_value(const string_t& value)
-        {
-            string = create<string_t>(value);
-        }
-
-        /// constructor for objects
-        json_value(const object_t& value)
-        {
-            object = create<object_t>(value);
-        }
-
-        /// constructor for arrays
-        json_value(const array_t& value)
-        {
-            array = create<array_t>(value);
-        }
-    };
-
-    /*!
-    @brief checks the class invariants
-
-    This function asserts the class invariants. It needs to be called at the
-    end of every constructor to make sure that created objects respect the
-    invariant. Furthermore, it has to be called each time the type of a JSON
-    value is changed, because the invariant expresses a relationship between
-    @a m_type and @a m_value.
-    */
-    void assert_invariant() const
-    {
-        assert(m_type != value_t::object or m_value.object != nullptr);
-        assert(m_type != value_t::array or m_value.array != nullptr);
-        assert(m_type != value_t::string or m_value.string != nullptr);
-    }
-
-  public:
-    //////////////////////////
-    // JSON parser callback //
-    //////////////////////////
-
-    /*!
-    @brief JSON callback events
-
-    This enumeration lists the parser events that can trigger calling a
-    callback function of type @ref parser_callback_t during parsing.
-
-    @image html callback_events.png "Example when certain parse events are triggered"
-
-    @since version 1.0.0
-    */
-    enum class parse_event_t : uint8_t
-    {
-        /// the parser read `{` and started to process a JSON object
-        object_start,
-        /// the parser read `}` and finished processing a JSON object
-        object_end,
-        /// the parser read `[` and started to process a JSON array
-        array_start,
-        /// the parser read `]` and finished processing a JSON array
-        array_end,
-        /// the parser read a key of a value in an object
-        key,
-        /// the parser finished reading a JSON value
-        value
-    };
-
-    /*!
-    @brief per-element parser callback type
-
-    With a parser callback function, the result of parsing a JSON text can be
-    influenced. When passed to @ref parse(std::istream&, const
-    parser_callback_t) or @ref parse(const string_t&, const parser_callback_t),
-    it is called on certain events (passed as @ref parse_event_t via parameter
-    @a event) with a set recursion depth @a depth and context JSON value
-    @a parsed. The return value of the callback function is a boolean
-    indicating whether the element that emitted the callback shall be kept or
-    not.
-
-    We distinguish six scenarios (determined by the event type) in which the
-    callback function can be called. The following table describes the values
-    of the parameters @a depth, @a event, and @a parsed.
-
-    parameter @a event | description | parameter @a depth | parameter @a parsed
-    ------------------ | ----------- | ------------------ | -------------------
-    parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded
-    parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key
-    parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object
-    parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded
-    parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
-    parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
-
-    @image html callback_events.png "Example when certain parse events are triggered"
-
-    Discarding a value (i.e., returning `false`) has different effects
-    depending on the context in which function was called:
-
-    - Discarded values in structured types are skipped. That is, the parser
-      will behave as if the discarded value was never read.
-    - In case a value outside a structured type is skipped, it is replaced
-      with `null`. This case happens if the top-level element is skipped.
-
-    @param[in] depth  the depth of the recursion during parsing
-
-    @param[in] event  an event of type parse_event_t indicating the context in
-    the callback function has been called
-
-    @param[in,out] parsed  the current intermediate parse result; note that
-    writing to this value has no effect for parse_event_t::key events
-
-    @return Whether the JSON value which called the function during parsing
-    should be kept (`true`) or not (`false`). In the latter case, it is either
-    skipped completely or replaced by an empty discarded object.
-
-    @sa @ref parse(std::istream&, parser_callback_t) or
-    @ref parse(const string_t&, parser_callback_t) for examples
-
-    @since version 1.0.0
-    */
-    using parser_callback_t = std::function<bool(int depth,
-                              parse_event_t event,
-                              basic_json& parsed)>;
-
-
-    //////////////////
-    // constructors //
-    //////////////////
-
-    /// @name constructors and destructors
-    /// Constructors of class @ref basic_json, copy/move constructor, copy
-    /// assignment, static functions creating objects, and the destructor.
-    /// @{
-
-    /*!
-    @brief create an empty value with a given type
-
-    Create an empty JSON value with a given type. The value will be default
-    initialized with an empty value which depends on the type:
-
-    Value type  | initial value
-    ----------- | -------------
-    null        | `null`
-    boolean     | `false`
-    string      | `""`
-    number      | `0`
-    object      | `{}`
-    array       | `[]`
-
-    @param[in] value_type  the type of the value to create
-
-    @complexity Constant.
-
-    @throw std::bad_alloc if allocation for object, array, or string value
-    fails
-
-    @liveexample{The following code shows the constructor for different @ref
-    value_t values,basic_json__value_t}
-
-    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
-    @sa @ref basic_json(boolean_t value) -- create a boolean value
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const object_t&) -- create a object value
-    @sa @ref basic_json(const array_t&) -- create a array value
-    @sa @ref basic_json(const number_float_t) -- create a number
-    (floating-point) value
-    @sa @ref basic_json(const number_integer_t) -- create a number (integer)
-    value
-    @sa @ref basic_json(const number_unsigned_t) -- create a number (unsigned)
-    value
-
-    @since version 1.0.0
-    */
-    basic_json(const value_t value_type)
-        : m_type(value_type), m_value(value_type)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a null object (implicitly)
-
-    Create a `null` JSON value. This is the implicit version of the `null`
-    value constructor as it takes no parameters.
-
-    @note The class invariant is satisfied, because it poses no requirements
-    for null values.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this constructor never throws
-    exceptions.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - As postcondition, it holds: `basic_json().empty() == true`.
-
-    @liveexample{The following code shows the constructor for a `null` JSON
-    value.,basic_json}
-
-    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
-
-    @since version 1.0.0
-    */
-    basic_json() = default;
-
-    /*!
-    @brief create a null object (explicitly)
-
-    Create a `null` JSON value. This is the explicitly version of the `null`
-    value constructor as it takes a null pointer as parameter. It allows to
-    create `null` values by explicitly assigning a `nullptr` to a JSON value.
-    The passed null pointer itself is not read -- it is only used to choose
-    the right constructor.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this constructor never throws
-    exceptions.
-
-    @liveexample{The following code shows the constructor with null pointer
-    parameter.,basic_json__nullptr_t}
-
-    @sa @ref basic_json() -- default constructor (implicitly creating a `null`
-    value)
-
-    @since version 1.0.0
-    */
-    basic_json(std::nullptr_t) noexcept
-        : basic_json(value_t::null)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an object (explicit)
-
-    Create an object JSON value with a given content.
-
-    @param[in] val  a value for the object
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for object value fails
-
-    @liveexample{The following code shows the constructor with an @ref
-    object_t parameter.,basic_json__object_t}
-
-    @sa @ref basic_json(const CompatibleObjectType&) -- create an object value
-    from a compatible STL container
-
-    @since version 1.0.0
-    */
-    basic_json(const object_t& val)
-        : m_type(value_t::object), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an object (implicit)
-
-    Create an object JSON value with a given content. This constructor allows
-    any type @a CompatibleObjectType that can be used to construct values of
-    type @ref object_t.
-
-    @tparam CompatibleObjectType An object type whose `key_type` and
-    `value_type` is compatible to @ref object_t. Examples include `std::map`,
-    `std::unordered_map`, `std::multimap`, and `std::unordered_multimap` with
-    a `key_type` of `std::string`, and a `value_type` from which a @ref
-    basic_json value can be constructed.
-
-    @param[in] val  a value for the object
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for object value fails
-
-    @liveexample{The following code shows the constructor with several
-    compatible object type parameters.,basic_json__CompatibleObjectType}
-
-    @sa @ref basic_json(const object_t&) -- create an object value
-
-    @since version 1.0.0
-    */
-    template <class CompatibleObjectType, typename
-              std::enable_if<
-                  std::is_constructible<typename object_t::key_type, typename CompatibleObjectType::key_type>::value and
-                  std::is_constructible<basic_json, typename CompatibleObjectType::mapped_type>::value, int>::type
-              = 0>
-    basic_json(const CompatibleObjectType& val)
-        : m_type(value_t::object)
-    {
-        using std::begin;
-        using std::end;
-        m_value.object = create<object_t>(begin(val), end(val));
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an array (explicit)
-
-    Create an array JSON value with a given content.
-
-    @param[in] val  a value for the array
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for array value fails
-
-    @liveexample{The following code shows the constructor with an @ref array_t
-    parameter.,basic_json__array_t}
-
-    @sa @ref basic_json(const CompatibleArrayType&) -- create an array value
-    from a compatible STL containers
-
-    @since version 1.0.0
-    */
-    basic_json(const array_t& val)
-        : m_type(value_t::array), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an array (implicit)
-
-    Create an array JSON value with a given content. This constructor allows
-    any type @a CompatibleArrayType that can be used to construct values of
-    type @ref array_t.
-
-    @tparam CompatibleArrayType An object type whose `value_type` is
-    compatible to @ref array_t. Examples include `std::vector`, `std::deque`,
-    `std::list`, `std::forward_list`, `std::array`, `std::set`,
-    `std::unordered_set`, `std::multiset`, and `unordered_multiset` with a
-    `value_type` from which a @ref basic_json value can be constructed.
-
-    @param[in] val  a value for the array
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for array value fails
-
-    @liveexample{The following code shows the constructor with several
-    compatible array type parameters.,basic_json__CompatibleArrayType}
-
-    @sa @ref basic_json(const array_t&) -- create an array value
-
-    @since version 1.0.0
-    */
-    template <class CompatibleArrayType, typename
-              std::enable_if<
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::reverse_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_reverse_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename array_t::iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename array_t::const_iterator>::value and
-                  std::is_constructible<basic_json, typename CompatibleArrayType::value_type>::value, int>::type
-              = 0>
-    basic_json(const CompatibleArrayType& val)
-        : m_type(value_t::array)
-    {
-        using std::begin;
-        using std::end;
-        m_value.array = create<array_t>(begin(val), end(val));
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a string (explicit)
-
-    Create an string JSON value with a given content.
-
-    @param[in] val  a value for the string
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for string value fails
-
-    @liveexample{The following code shows the constructor with an @ref
-    string_t parameter.,basic_json__string_t}
-
-    @sa @ref basic_json(const typename string_t::value_type*) -- create a
-    string value from a character pointer
-    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
-    from a compatible string container
-
-    @since version 1.0.0
-    */
-    basic_json(const string_t& val)
-        : m_type(value_t::string), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a string (explicit)
-
-    Create a string JSON value with a given content.
-
-    @param[in] val  a literal value for the string
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for string value fails
-
-    @liveexample{The following code shows the constructor with string literal
-    parameter.,basic_json__string_t_value_type}
-
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
-    from a compatible string container
-
-    @since version 1.0.0
-    */
-    basic_json(const typename string_t::value_type* val)
-        : basic_json(string_t(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a string (implicit)
-
-    Create a string JSON value with a given content.
-
-    @param[in] val  a value for the string
-
-    @tparam CompatibleStringType an string type which is compatible to @ref
-    string_t, for instance `std::string`.
-
-    @complexity Linear in the size of the passed @a val.
-
-    @throw std::bad_alloc if allocation for string value fails
-
-    @liveexample{The following code shows the construction of a string value
-    from a compatible type.,basic_json__CompatibleStringType}
-
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const typename string_t::value_type*) -- create a
-    string value from a character pointer
-
-    @since version 1.0.0
-    */
-    template <class CompatibleStringType, typename
-              std::enable_if<
-                  std::is_constructible<string_t, CompatibleStringType>::value, int>::type
-              = 0>
-    basic_json(const CompatibleStringType& val)
-        : basic_json(string_t(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a boolean (explicit)
-
-    Creates a JSON boolean type from a given value.
-
-    @param[in] val  a boolean value to store
-
-    @complexity Constant.
-
-    @liveexample{The example below demonstrates boolean
-    values.,basic_json__boolean_t}
-
-    @since version 1.0.0
-    */
-    basic_json(boolean_t val) noexcept
-        : m_type(value_t::boolean), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an integer number (explicit)
-
-    Create an integer number JSON value with a given content.
-
-    @tparam T A helper type to remove this function via SFINAE in case @ref
-    number_integer_t is the same as `int`. In this case, this constructor
-    would have the same signature as @ref basic_json(const int value). Note
-    the helper type @a T is not visible in this constructor's interface.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @complexity Constant.
-
-    @liveexample{The example below shows the construction of an integer
-    number value.,basic_json__number_integer_t}
-
-    @sa @ref basic_json(const int) -- create a number value (integer)
-    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
-    value (integer) from a compatible number type
-
-    @since version 1.0.0
-    */
-    template<typename T,
-             typename std::enable_if<
-                 not (std::is_same<T, int>::value)
-                 and std::is_same<T, number_integer_t>::value
-                 , int>::type
-             = 0>
-    basic_json(const number_integer_t val) noexcept
-        : m_type(value_t::number_integer), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an integer number from an enum type (explicit)
-
-    Create an integer number JSON value with a given content.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @note This constructor allows to pass enums directly to a constructor. As
-    C++ has no way of specifying the type of an anonymous enum explicitly, we
-    can only rely on the fact that such values implicitly convert to int. As
-    int may already be the same type of number_integer_t, we may need to
-    switch off the constructor @ref basic_json(const number_integer_t).
-
-    @complexity Constant.
-
-    @liveexample{The example below shows the construction of an integer
-    number value from an anonymous enum.,basic_json__const_int}
-
-    @sa @ref basic_json(const number_integer_t) -- create a number value
-    (integer)
-    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
-    value (integer) from a compatible number type
-
-    @since version 1.0.0
-    */
-    basic_json(const int val) noexcept
-        : m_type(value_t::number_integer),
-          m_value(static_cast<number_integer_t>(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an integer number (implicit)
-
-    Create an integer number JSON value with a given content. This constructor
-    allows any type @a CompatibleNumberIntegerType that can be used to
-    construct values of type @ref number_integer_t.
-
-    @tparam CompatibleNumberIntegerType An integer type which is compatible to
-    @ref number_integer_t. Examples include the types `int`, `int32_t`,
-    `long`, and `short`.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @complexity Constant.
-
-    @liveexample{The example below shows the construction of several integer
-    number values from compatible
-    types.,basic_json__CompatibleIntegerNumberType}
-
-    @sa @ref basic_json(const number_integer_t) -- create a number value
-    (integer)
-    @sa @ref basic_json(const int) -- create a number value (integer)
-
-    @since version 1.0.0
-    */
-    template<typename CompatibleNumberIntegerType, typename
-             std::enable_if<
-                 std::is_constructible<number_integer_t, CompatibleNumberIntegerType>::value and
-                 std::numeric_limits<CompatibleNumberIntegerType>::is_integer and
-                 std::numeric_limits<CompatibleNumberIntegerType>::is_signed,
-                 CompatibleNumberIntegerType>::type
-             = 0>
-    basic_json(const CompatibleNumberIntegerType val) noexcept
-        : m_type(value_t::number_integer),
-          m_value(static_cast<number_integer_t>(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an unsigned integer number (explicit)
-
-    Create an unsigned integer number JSON value with a given content.
-
-    @tparam T  helper type to compare number_unsigned_t and unsigned int (not
-    visible in) the interface.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @complexity Constant.
-
-    @sa @ref basic_json(const CompatibleNumberUnsignedType) -- create a number
-    value (unsigned integer) from a compatible number type
-
-    @since version 2.0.0
-    */
-    template<typename T,
-             typename std::enable_if<
-                 not (std::is_same<T, int>::value)
-                 and std::is_same<T, number_unsigned_t>::value
-                 , int>::type
-             = 0>
-    basic_json(const number_unsigned_t val) noexcept
-        : m_type(value_t::number_unsigned), m_value(val)
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an unsigned number (implicit)
-
-    Create an unsigned number JSON value with a given content. This
-    constructor allows any type @a CompatibleNumberUnsignedType that can be
-    used to construct values of type @ref number_unsigned_t.
-
-    @tparam CompatibleNumberUnsignedType An integer type which is compatible
-    to @ref number_unsigned_t. Examples may include the types `unsigned int`,
-    `uint32_t`, or `unsigned short`.
-
-    @param[in] val  an unsigned integer to create a JSON number from
-
-    @complexity Constant.
-
-    @sa @ref basic_json(const number_unsigned_t) -- create a number value
-    (unsigned)
-
-    @since version 2.0.0
-    */
-    template <typename CompatibleNumberUnsignedType, typename
-              std::enable_if <
-                  std::is_constructible<number_unsigned_t, CompatibleNumberUnsignedType>::value and
-                  std::numeric_limits<CompatibleNumberUnsignedType>::is_integer and
-                  not std::numeric_limits<CompatibleNumberUnsignedType>::is_signed,
-                  CompatibleNumberUnsignedType>::type
-              = 0>
-    basic_json(const CompatibleNumberUnsignedType val) noexcept
-        : m_type(value_t::number_unsigned),
-          m_value(static_cast<number_unsigned_t>(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a floating-point number (explicit)
-
-    Create a floating-point number JSON value with a given content.
-
-    @param[in] val  a floating-point value to create a JSON number from
-
-    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
-    disallows NaN values:
-    > Numeric values that cannot be represented in the grammar below (such as
-    > Infinity and NaN) are not permitted.
-    In case the parameter @a val is not a number, a JSON null value is created
-    instead.
-
-    @complexity Constant.
-
-    @liveexample{The following example creates several floating-point
-    values.,basic_json__number_float_t}
-
-    @sa @ref basic_json(const CompatibleNumberFloatType) -- create a number
-    value (floating-point) from a compatible number type
-
-    @since version 1.0.0
-    */
-    basic_json(const number_float_t val) noexcept
-        : m_type(value_t::number_float), m_value(val)
-    {
-        // replace infinity and NAN by null
-        if (not std::isfinite(val))
-        {
-            m_type = value_t::null;
-            m_value = json_value();
-        }
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief create an floating-point number (implicit)
-
-    Create an floating-point number JSON value with a given content. This
-    constructor allows any type @a CompatibleNumberFloatType that can be used
-    to construct values of type @ref number_float_t.
-
-    @tparam CompatibleNumberFloatType A floating-point type which is
-    compatible to @ref number_float_t. Examples may include the types `float`
-    or `double`.
-
-    @param[in] val  a floating-point to create a JSON number from
-
-    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
-    disallows NaN values:
-    > Numeric values that cannot be represented in the grammar below (such as
-    > Infinity and NaN) are not permitted.
-    In case the parameter @a val is not a number, a JSON null value is
-    created instead.
-
-    @complexity Constant.
-
-    @liveexample{The example below shows the construction of several
-    floating-point number values from compatible
-    types.,basic_json__CompatibleNumberFloatType}
-
-    @sa @ref basic_json(const number_float_t) -- create a number value
-    (floating-point)
-
-    @since version 1.0.0
-    */
-    template<typename CompatibleNumberFloatType, typename = typename
-             std::enable_if<
-                 std::is_constructible<number_float_t, CompatibleNumberFloatType>::value and
-                 std::is_floating_point<CompatibleNumberFloatType>::value>::type
-             >
-    basic_json(const CompatibleNumberFloatType val) noexcept
-        : basic_json(number_float_t(val))
-    {
-        assert_invariant();
-    }
-
-    /*!
-    @brief create a container (array or object) from an initializer list
-
-    Creates a JSON value of type array or object from the passed initializer
-    list @a init. In case @a type_deduction is `true` (default), the type of
-    the JSON value to be created is deducted from the initializer list @a init
-    according to the following rules:
-
-    1. If the list is empty, an empty JSON object value `{}` is created.
-    2. If the list consists of pairs whose first element is a string, a JSON
-       object value is created where the first elements of the pairs are
-       treated as keys and the second elements are as values.
-    3. In all other cases, an array is created.
-
-    The rules aim to create the best fit between a C++ initializer list and
-    JSON values. The rationale is as follows:
-
-    1. The empty initializer list is written as `{}` which is exactly an empty
-       JSON object.
-    2. C++ has now way of describing mapped types other than to list a list of
-       pairs. As JSON requires that keys must be of type string, rule 2 is the
-       weakest constraint one can pose on initializer lists to interpret them
-       as an object.
-    3. In all other cases, the initializer list could not be interpreted as
-       JSON object type, so interpreting it as JSON array type is safe.
-
-    With the rules described above, the following JSON values cannot be
-    expressed by an initializer list:
-
-    - the empty array (`[]`): use @ref array(std::initializer_list<basic_json>)
-      with an empty initializer list in this case
-    - arrays whose elements satisfy rule 2: use @ref
-      array(std::initializer_list<basic_json>) with the same initializer list
-      in this case
-
-    @note When used without parentheses around an empty initializer list, @ref
-    basic_json() is called instead of this function, yielding the JSON null
-    value.
-
-    @param[in] init  initializer list with JSON values
-
-    @param[in] type_deduction internal parameter; when set to `true`, the type
-    of the JSON value is deducted from the initializer list @a init; when set
-    to `false`, the type provided via @a manual_type is forced. This mode is
-    used by the functions @ref array(std::initializer_list<basic_json>) and
-    @ref object(std::initializer_list<basic_json>).
-
-    @param[in] manual_type internal parameter; when @a type_deduction is set
-    to `false`, the created JSON value will use the provided type (only @ref
-    value_t::array and @ref value_t::object are valid); when @a type_deduction
-    is set to `true`, this parameter has no effect
-
-    @throw std::domain_error if @a type_deduction is `false`, @a manual_type
-    is `value_t::object`, but @a init contains an element which is not a pair
-    whose first element is a string; example: `"cannot create object from
-    initializer list"`
-
-    @complexity Linear in the size of the initializer list @a init.
-
-    @liveexample{The example below shows how JSON values are created from
-    initializer lists.,basic_json__list_init_t}
-
-    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
-    value from an initializer list
-    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
-    value from an initializer list
-
-    @since version 1.0.0
-    */
-    basic_json(std::initializer_list<basic_json> init,
-               bool type_deduction = true,
-               value_t manual_type = value_t::array)
-    {
-        // check if each element is an array with two elements whose first
-        // element is a string
-        bool is_an_object = std::all_of(init.begin(), init.end(),
-                                        [](const basic_json & element)
-        {
-            return element.is_array() and element.size() == 2 and element[0].is_string();
-        });
-
-        // adjust type if type deduction is not wanted
-        if (not type_deduction)
-        {
-            // if array is wanted, do not create an object though possible
-            if (manual_type == value_t::array)
-            {
-                is_an_object = false;
-            }
-
-            // if object is wanted but impossible, throw an exception
-            if (manual_type == value_t::object and not is_an_object)
-            {
-                throw std::domain_error("cannot create object from initializer list");
-            }
-        }
-
-        if (is_an_object)
-        {
-            // the initializer list is a list of pairs -> create object
-            m_type = value_t::object;
-            m_value = value_t::object;
-
-            std::for_each(init.begin(), init.end(), [this](const basic_json & element)
-            {
-                m_value.object->emplace(*(element[0].m_value.string), element[1]);
-            });
-        }
-        else
-        {
-            // the initializer list describes an array -> create array
-            m_type = value_t::array;
-            m_value.array = create<array_t>(init);
-        }
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief explicitly create an array from an initializer list
-
-    Creates a JSON array value from a given initializer list. That is, given a
-    list of values `a, b, c`, creates the JSON value `[a, b, c]`. If the
-    initializer list is empty, the empty array `[]` is created.
-
-    @note This function is only needed to express two edge cases that cannot
-    be realized with the initializer list constructor (@ref
-    basic_json(std::initializer_list<basic_json>, bool, value_t)). These cases
-    are:
-    1. creating an array whose elements are all pairs whose first element is a
-    string -- in this case, the initializer list constructor would create an
-    object, taking the first elements as keys
-    2. creating an empty array -- passing the empty initializer list to the
-    initializer list constructor yields an empty object
-
-    @param[in] init  initializer list with JSON values to create an array from
-    (optional)
-
-    @return JSON array value
-
-    @complexity Linear in the size of @a init.
-
-    @liveexample{The following code shows an example for the `array`
-    function.,array}
-
-    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
-    create a JSON value from an initializer list
-    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
-    value from an initializer list
-
-    @since version 1.0.0
-    */
-    static basic_json array(std::initializer_list<basic_json> init =
-                                std::initializer_list<basic_json>())
-    {
-        return basic_json(init, false, value_t::array);
-    }
-
-    /*!
-    @brief explicitly create an object from an initializer list
-
-    Creates a JSON object value from a given initializer list. The initializer
-    lists elements must be pairs, and their first elements must be strings. If
-    the initializer list is empty, the empty object `{}` is created.
-
-    @note This function is only added for symmetry reasons. In contrast to the
-    related function @ref array(std::initializer_list<basic_json>), there are
-    no cases which can only be expressed by this function. That is, any
-    initializer list @a init can also be passed to the initializer list
-    constructor @ref basic_json(std::initializer_list<basic_json>, bool,
-    value_t).
-
-    @param[in] init  initializer list to create an object from (optional)
-
-    @return JSON object value
-
-    @throw std::domain_error if @a init is not a pair whose first elements are
-    strings; thrown by
-    @ref basic_json(std::initializer_list<basic_json>, bool, value_t)
-
-    @complexity Linear in the size of @a init.
-
-    @liveexample{The following code shows an example for the `object`
-    function.,object}
-
-    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
-    create a JSON value from an initializer list
-    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
-    value from an initializer list
-
-    @since version 1.0.0
-    */
-    static basic_json object(std::initializer_list<basic_json> init =
-                                 std::initializer_list<basic_json>())
-    {
-        return basic_json(init, false, value_t::object);
-    }
-
-    /*!
-    @brief construct an array with count copies of given value
-
-    Constructs a JSON array value by creating @a cnt copies of a passed value.
-    In case @a cnt is `0`, an empty array is created. As postcondition,
-    `std::distance(begin(),end()) == cnt` holds.
-
-    @param[in] cnt  the number of JSON copies of @a val to create
-    @param[in] val  the JSON value to copy
-
-    @complexity Linear in @a cnt.
-
-    @liveexample{The following code shows examples for the @ref
-    basic_json(size_type\, const basic_json&)
-    constructor.,basic_json__size_type_basic_json}
-
-    @since version 1.0.0
-    */
-    basic_json(size_type cnt, const basic_json& val)
-        : m_type(value_t::array)
-    {
-        m_value.array = create<array_t>(cnt, val);
-        assert_invariant();
-    }
-
-    /*!
-    @brief construct a JSON container given an iterator range
-
-    Constructs the JSON value with the contents of the range `[first, last)`.
-    The semantics depends on the different types a JSON value can have:
-    - In case of primitive types (number, boolean, or string), @a first must
-      be `begin()` and @a last must be `end()`. In this case, the value is
-      copied. Otherwise, std::out_of_range is thrown.
-    - In case of structured types (array, object), the constructor behaves as
-      similar versions for `std::vector`.
-    - In case of a null type, std::domain_error is thrown.
-
-    @tparam InputIT an input iterator type (@ref iterator or @ref
-    const_iterator)
-
-    @param[in] first begin of the range to copy from (included)
-    @param[in] last end of the range to copy from (excluded)
-
-    @pre Iterators @a first and @a last must be initialized.
-
-    @throw std::domain_error if iterators are not compatible; that is, do not
-    belong to the same JSON value; example: `"iterators are not compatible"`
-    @throw std::out_of_range if iterators are for a primitive type (number,
-    boolean, or string) where an out of range error can be detected easily;
-    example: `"iterators out of range"`
-    @throw std::bad_alloc if allocation for object, array, or string fails
-    @throw std::domain_error if called with a null value; example: `"cannot
-    use construct with iterators from null"`
-
-    @complexity Linear in distance between @a first and @a last.
-
-    @liveexample{The example below shows several ways to create JSON values by
-    specifying a subrange with iterators.,basic_json__InputIt_InputIt}
-
-    @since version 1.0.0
-    */
-    template <class InputIT, typename
-              std::enable_if<
-                  std::is_same<InputIT, typename basic_json_t::iterator>::value or
-                  std::is_same<InputIT, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
-    basic_json(InputIT first, InputIT last)
-    {
-        assert(first.m_object != nullptr);
-        assert(last.m_object != nullptr);
-
-        // make sure iterator fits the current value
-        if (first.m_object != last.m_object)
-        {
-            throw std::domain_error("iterators are not compatible");
-        }
-
-        // copy type from first iterator
-        m_type = first.m_object->m_type;
-
-        // check if iterator range is complete for primitive values
-        switch (m_type)
-        {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
-            {
-                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
-                {
-                    throw std::out_of_range("iterators out of range");
-                }
-                break;
-            }
-
-            default:
-            {
-                break;
-            }
-        }
-
-        switch (m_type)
-        {
-            case value_t::number_integer:
-            {
-                m_value.number_integer = first.m_object->m_value.number_integer;
-                break;
-            }
-
-            case value_t::number_unsigned:
-            {
-                m_value.number_unsigned = first.m_object->m_value.number_unsigned;
-                break;
-            }
-
-            case value_t::number_float:
-            {
-                m_value.number_float = first.m_object->m_value.number_float;
-                break;
-            }
-
-            case value_t::boolean:
-            {
-                m_value.boolean = first.m_object->m_value.boolean;
-                break;
-            }
-
-            case value_t::string:
-            {
-                m_value = *first.m_object->m_value.string;
-                break;
-            }
-
-            case value_t::object:
-            {
-                m_value.object = create<object_t>(first.m_it.object_iterator, last.m_it.object_iterator);
-                break;
-            }
-
-            case value_t::array:
-            {
-                m_value.array = create<array_t>(first.m_it.array_iterator, last.m_it.array_iterator);
-                break;
-            }
-
-            default:
-            {
-                throw std::domain_error("cannot use construct with iterators from " + first.m_object->type_name());
-            }
-        }
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief construct a JSON value given an input stream
-
-    @param[in,out] i  stream to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below demonstrates constructing a JSON value from
-    a `std::stringstream` with and without callback
-    function.,basic_json__istream}
-
-    @since version 2.0.0
-    */
-    explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)
-    {
-        *this = parser(i, cb).parse();
-        assert_invariant();
-    }
-
-    ///////////////////////////////////////
-    // other constructors and destructor //
-    ///////////////////////////////////////
-
-    /*!
-    @brief copy constructor
-
-    Creates a copy of a given JSON value.
-
-    @param[in] other  the JSON value to copy
-
-    @complexity Linear in the size of @a other.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-    - As postcondition, it holds: `other == basic_json(other)`.
-
-    @throw std::bad_alloc if allocation for object, array, or string fails.
-
-    @liveexample{The following code shows an example for the copy
-    constructor.,basic_json__basic_json}
-
-    @since version 1.0.0
-    */
-    basic_json(const basic_json& other)
-        : m_type(other.m_type)
-    {
-        // check of passed value is valid
-        other.assert_invariant();
-
-        switch (m_type)
-        {
-            case value_t::object:
-            {
-                m_value = *other.m_value.object;
-                break;
-            }
-
-            case value_t::array:
-            {
-                m_value = *other.m_value.array;
-                break;
-            }
-
-            case value_t::string:
-            {
-                m_value = *other.m_value.string;
-                break;
-            }
-
-            case value_t::boolean:
-            {
-                m_value = other.m_value.boolean;
-                break;
-            }
-
-            case value_t::number_integer:
-            {
-                m_value = other.m_value.number_integer;
-                break;
-            }
-
-            case value_t::number_unsigned:
-            {
-                m_value = other.m_value.number_unsigned;
-                break;
-            }
-
-            case value_t::number_float:
-            {
-                m_value = other.m_value.number_float;
-                break;
-            }
-
-            default:
-            {
-                break;
-            }
-        }
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief move constructor
-
-    Move constructor. Constructs a JSON value with the contents of the given
-    value @a other using move semantics. It "steals" the resources from @a
-    other and leaves it as JSON null value.
-
-    @param[in,out] other  value to move to this object
-
-    @post @a other is a JSON null value
-
-    @complexity Constant.
-
-    @liveexample{The code below shows the move constructor explicitly called
-    via std::move.,basic_json__moveconstructor}
-
-    @since version 1.0.0
-    */
-    basic_json(basic_json&& other) noexcept
-        : m_type(std::move(other.m_type)),
-          m_value(std::move(other.m_value))
-    {
-        // check that passed value is valid
-        other.assert_invariant();
-
-        // invalidate payload
-        other.m_type = value_t::null;
-        other.m_value = {};
-
-        assert_invariant();
-    }
-
-    /*!
-    @brief copy assignment
-
-    Copy assignment operator. Copies a JSON value via the "copy and swap"
-    strategy: It is expressed in terms of the copy constructor, destructor,
-    and the swap() member function.
-
-    @param[in] other  value to copy from
-
-    @complexity Linear.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-
-    @liveexample{The code below shows and example for the copy assignment. It
-    creates a copy of value `a` which is then swapped with `b`. Finally\, the
-    copy of `a` (which is the null value after the swap) is
-    destroyed.,basic_json__copyassignment}
-
-    @since version 1.0.0
-    */
-    reference& operator=(basic_json other) noexcept (
-        std::is_nothrow_move_constructible<value_t>::value and
-        std::is_nothrow_move_assignable<value_t>::value and
-        std::is_nothrow_move_constructible<json_value>::value and
-        std::is_nothrow_move_assignable<json_value>::value
-    )
-    {
-        // check that passed value is valid
-        other.assert_invariant();
-
-        using std::swap;
-        swap(m_type, other.m_type);
-        swap(m_value, other.m_value);
-
-        assert_invariant();
-        return *this;
-    }
-
-    /*!
-    @brief destructor
-
-    Destroys the JSON value and frees all allocated memory.
-
-    @complexity Linear.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-    - All stored elements are destroyed and all memory is freed.
-
-    @since version 1.0.0
-    */
-    ~basic_json()
-    {
-        assert_invariant();
-
-        switch (m_type)
-        {
-            case value_t::object:
-            {
-                AllocatorType<object_t> alloc;
-                alloc.destroy(m_value.object);
-                alloc.deallocate(m_value.object, 1);
-                break;
-            }
-
-            case value_t::array:
-            {
-                AllocatorType<array_t> alloc;
-                alloc.destroy(m_value.array);
-                alloc.deallocate(m_value.array, 1);
-                break;
-            }
-
-            case value_t::string:
-            {
-                AllocatorType<string_t> alloc;
-                alloc.destroy(m_value.string);
-                alloc.deallocate(m_value.string, 1);
-                break;
-            }
-
-            default:
-            {
-                // all other types need no specific destructor
-                break;
-            }
-        }
-    }
-
-    /// @}
-
-  public:
-    ///////////////////////
-    // object inspection //
-    ///////////////////////
-
-    /// @name object inspection
-    /// Functions to inspect the type of a JSON value.
-    /// @{
-
-    /*!
-    @brief serialization
-
-    Serialization function for JSON values. The function tries to mimic
-    Python's `json.dumps()` function, and currently supports its @a indent
-    parameter.
-
-    @param[in] indent If indent is nonnegative, then array elements and object
-    members will be pretty-printed with that indent level. An indent level of
-    `0` will only insert newlines. `-1` (the default) selects the most compact
-    representation.
-
-    @return string containing the serialization of the JSON value
-
-    @complexity Linear.
-
-    @liveexample{The following example shows the effect of different @a indent
-    parameters to the result of the serialization.,dump}
-
-    @see https://docs.python.org/2/library/json.html#json.dump
-
-    @since version 1.0.0
-    */
-    string_t dump(const int indent = -1) const
-    {
-        std::stringstream ss;
-        // fix locale problems
-        ss.imbue(std::locale(std::locale(), new DecimalSeparator));
-
-        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
-        // string->float->string, string->double->string or string->long
-        // double->string; to be safe, we read this value from
-        // std::numeric_limits<number_float_t>::digits10
-        ss.precision(std::numeric_limits<double>::digits10);
-
-        if (indent >= 0)
-        {
-            dump(ss, true, static_cast<unsigned int>(indent));
-        }
-        else
-        {
-            dump(ss, false, 0);
-        }
-
-        return ss.str();
-    }
-
-    /*!
-    @brief return the type of the JSON value (explicit)
-
-    Return the type of the JSON value as a value from the @ref value_t
-    enumeration.
-
-    @return the type of the JSON value
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `type()` for all JSON
-    types.,type}
-
-    @since version 1.0.0
-    */
-    constexpr value_t type() const noexcept
-    {
-        return m_type;
-    }
-
-    /*!
-    @brief return whether type is primitive
-
-    This function returns true iff the JSON type is primitive (string, number,
-    boolean, or null).
-
-    @return `true` if type is primitive (string, number, boolean, or null),
-    `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_primitive()` for all JSON
-    types.,is_primitive}
-
-    @sa @ref is_structured() -- returns whether JSON value is structured
-    @sa @ref is_null() -- returns whether JSON value is `null`
-    @sa @ref is_string() -- returns whether JSON value is a string
-    @sa @ref is_boolean() -- returns whether JSON value is a boolean
-    @sa @ref is_number() -- returns whether JSON value is a number
-
-    @since version 1.0.0
-    */
-    constexpr bool is_primitive() const noexcept
-    {
-        return is_null() or is_string() or is_boolean() or is_number();
-    }
-
-    /*!
-    @brief return whether type is structured
-
-    This function returns true iff the JSON type is structured (array or
-    object).
-
-    @return `true` if type is structured (array or object), `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_structured()` for all JSON
-    types.,is_structured}
-
-    @sa @ref is_primitive() -- returns whether value is primitive
-    @sa @ref is_array() -- returns whether value is an array
-    @sa @ref is_object() -- returns whether value is an object
-
-    @since version 1.0.0
-    */
-    constexpr bool is_structured() const noexcept
-    {
-        return is_array() or is_object();
-    }
-
-    /*!
-    @brief return whether value is null
-
-    This function returns true iff the JSON value is null.
-
-    @return `true` if type is null, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_null()` for all JSON
-    types.,is_null}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_null() const noexcept
-    {
-        return m_type == value_t::null;
-    }
-
-    /*!
-    @brief return whether value is a boolean
-
-    This function returns true iff the JSON value is a boolean.
-
-    @return `true` if type is boolean, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_boolean()` for all JSON
-    types.,is_boolean}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_boolean() const noexcept
-    {
-        return m_type == value_t::boolean;
-    }
-
-    /*!
-    @brief return whether value is a number
-
-    This function returns true iff the JSON value is a number. This includes
-    both integer and floating-point values.
-
-    @return `true` if type is number (regardless whether integer, unsigned
-    integer or floating-type), `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number()` for all JSON
-    types.,is_number}
-
-    @sa @ref is_number_integer() -- check if value is an integer or unsigned
-    integer number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
-    @sa @ref is_number_float() -- check if value is a floating-point number
-
-    @since version 1.0.0
-    */
-    constexpr bool is_number() const noexcept
-    {
-        return is_number_integer() or is_number_float();
-    }
-
-    /*!
-    @brief return whether value is an integer number
-
-    This function returns true iff the JSON value is an integer or unsigned
-    integer number. This excludes floating-point values.
-
-    @return `true` if type is an integer or unsigned integer number, `false`
-    otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number_integer()` for all
-    JSON types.,is_number_integer}
-
-    @sa @ref is_number() -- check if value is a number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
-    @sa @ref is_number_float() -- check if value is a floating-point number
-
-    @since version 1.0.0
-    */
-    constexpr bool is_number_integer() const noexcept
-    {
-        return m_type == value_t::number_integer or m_type == value_t::number_unsigned;
-    }
-
-    /*!
-    @brief return whether value is an unsigned integer number
-
-    This function returns true iff the JSON value is an unsigned integer
-    number. This excludes floating-point and (signed) integer values.
-
-    @return `true` if type is an unsigned integer number, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number_unsigned()` for all
-    JSON types.,is_number_unsigned}
-
-    @sa @ref is_number() -- check if value is a number
-    @sa @ref is_number_integer() -- check if value is an integer or unsigned
-    integer number
-    @sa @ref is_number_float() -- check if value is a floating-point number
-
-    @since version 2.0.0
-    */
-    constexpr bool is_number_unsigned() const noexcept
-    {
-        return m_type == value_t::number_unsigned;
-    }
-
-    /*!
-    @brief return whether value is a floating-point number
-
-    This function returns true iff the JSON value is a floating-point number.
-    This excludes integer and unsigned integer values.
-
-    @return `true` if type is a floating-point number, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number_float()` for all
-    JSON types.,is_number_float}
-
-    @sa @ref is_number() -- check if value is number
-    @sa @ref is_number_integer() -- check if value is an integer number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
-
-    @since version 1.0.0
-    */
-    constexpr bool is_number_float() const noexcept
-    {
-        return m_type == value_t::number_float;
-    }
-
-    /*!
-    @brief return whether value is an object
-
-    This function returns true iff the JSON value is an object.
-
-    @return `true` if type is object, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_object()` for all JSON
-    types.,is_object}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_object() const noexcept
-    {
-        return m_type == value_t::object;
-    }
-
-    /*!
-    @brief return whether value is an array
-
-    This function returns true iff the JSON value is an array.
-
-    @return `true` if type is array, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_array()` for all JSON
-    types.,is_array}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_array() const noexcept
-    {
-        return m_type == value_t::array;
-    }
-
-    /*!
-    @brief return whether value is a string
-
-    This function returns true iff the JSON value is a string.
-
-    @return `true` if type is string, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_string()` for all JSON
-    types.,is_string}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_string() const noexcept
-    {
-        return m_type == value_t::string;
-    }
-
-    /*!
-    @brief return whether value is discarded
-
-    This function returns true iff the JSON value was discarded during parsing
-    with a callback function (see @ref parser_callback_t).
-
-    @note This function will always be `false` for JSON values after parsing.
-    That is, discarded values can only occur during parsing, but will be
-    removed when inside a structured value or replaced by null in other cases.
-
-    @return `true` if type is discarded, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_discarded()` for all JSON
-    types.,is_discarded}
-
-    @since version 1.0.0
-    */
-    constexpr bool is_discarded() const noexcept
-    {
-        return m_type == value_t::discarded;
-    }
-
-    /*!
-    @brief return the type of the JSON value (implicit)
-
-    Implicitly return the type of the JSON value as a value from the @ref
-    value_t enumeration.
-
-    @return the type of the JSON value
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies the @ref value_t operator for
-    all JSON types.,operator__value_t}
-
-    @since version 1.0.0
-    */
-    constexpr operator value_t() const noexcept
-    {
-        return m_type;
-    }
-
-    /// @}
-
-  private:
-    //////////////////
-    // value access //
-    //////////////////
-
-    /// get an object (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<typename object_t::key_type, typename T::key_type>::value and
-                  std::is_convertible<basic_json_t, typename T::mapped_type>::value
-                  , int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_object())
-        {
-            return T(m_value.object->begin(), m_value.object->end());
-        }
-        else
-        {
-            throw std::domain_error("type must be object, but is " + type_name());
-        }
-    }
-
-    /// get an object (explicit)
-    object_t get_impl(object_t*) const
-    {
-        if (is_object())
-        {
-            return *(m_value.object);
-        }
-        else
-        {
-            throw std::domain_error("type must be object, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, typename T::value_type>::value and
-                  not std::is_same<basic_json_t, typename T::value_type>::value and
-                  not std::is_arithmetic<T>::value and
-                  not std::is_convertible<std::string, T>::value and
-                  not has_mapped_type<T>::value
-                  , int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_array())
-        {
-            T to_vector;
-            std::transform(m_value.array->begin(), m_value.array->end(),
-                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
-            {
-                return i.get<typename T::value_type>();
-            });
-            return to_vector;
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, T>::value and
-                  not std::is_same<basic_json_t, T>::value
-                  , int>::type = 0>
-    std::vector<T> get_impl(std::vector<T>*) const
-    {
-        if (is_array())
-        {
-            std::vector<T> to_vector;
-            to_vector.reserve(m_value.array->size());
-            std::transform(m_value.array->begin(), m_value.array->end(),
-                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
-            {
-                return i.get<T>();
-            });
-            return to_vector;
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_same<basic_json, typename T::value_type>::value and
-                  not has_mapped_type<T>::value
-                  , int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_array())
-        {
-            return T(m_value.array->begin(), m_value.array->end());
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    array_t get_impl(array_t*) const
-    {
-        if (is_array())
-        {
-            return *(m_value.array);
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get a string (explicit)
-    template <typename T, typename
-              std::enable_if<
-                  std::is_convertible<string_t, T>::value
-                  , int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_string())
-        {
-            return *m_value.string;
-        }
-        else
-        {
-            throw std::domain_error("type must be string, but is " + type_name());
-        }
-    }
-
-    /// get a number (explicit)
-    template<typename T, typename
-             std::enable_if<
-                 std::is_arithmetic<T>::value
-                 , int>::type = 0>
-    T get_impl(T*) const
-    {
-        switch (m_type)
-        {
-            case value_t::number_integer:
-            {
-                return static_cast<T>(m_value.number_integer);
-            }
-
-            case value_t::number_unsigned:
-            {
-                return static_cast<T>(m_value.number_unsigned);
-            }
-
-            case value_t::number_float:
-            {
-                return static_cast<T>(m_value.number_float);
-            }
-
-            default:
-            {
-                throw std::domain_error("type must be number, but is " + type_name());
-            }
-        }
-    }
-
-    /// get a boolean (explicit)
-    constexpr boolean_t get_impl(boolean_t*) const
-    {
-        return is_boolean()
-               ? m_value.boolean
-               : throw std::domain_error("type must be boolean, but is " + type_name());
-    }
-
-    /// get a pointer to the value (object)
-    object_t* get_impl_ptr(object_t*) noexcept
-    {
-        return is_object() ? m_value.object : nullptr;
-    }
-
-    /// get a pointer to the value (object)
-    constexpr const object_t* get_impl_ptr(const object_t*) const noexcept
-    {
-        return is_object() ? m_value.object : nullptr;
-    }
-
-    /// get a pointer to the value (array)
-    array_t* get_impl_ptr(array_t*) noexcept
-    {
-        return is_array() ? m_value.array : nullptr;
-    }
-
-    /// get a pointer to the value (array)
-    constexpr const array_t* get_impl_ptr(const array_t*) const noexcept
-    {
-        return is_array() ? m_value.array : nullptr;
-    }
-
-    /// get a pointer to the value (string)
-    string_t* get_impl_ptr(string_t*) noexcept
-    {
-        return is_string() ? m_value.string : nullptr;
-    }
-
-    /// get a pointer to the value (string)
-    constexpr const string_t* get_impl_ptr(const string_t*) const noexcept
-    {
-        return is_string() ? m_value.string : nullptr;
-    }
-
-    /// get a pointer to the value (boolean)
-    boolean_t* get_impl_ptr(boolean_t*) noexcept
-    {
-        return is_boolean() ? &m_value.boolean : nullptr;
-    }
-
-    /// get a pointer to the value (boolean)
-    constexpr const boolean_t* get_impl_ptr(const boolean_t*) const noexcept
-    {
-        return is_boolean() ? &m_value.boolean : nullptr;
-    }
-
-    /// get a pointer to the value (integer number)
-    number_integer_t* get_impl_ptr(number_integer_t*) noexcept
-    {
-        return is_number_integer() ? &m_value.number_integer : nullptr;
-    }
-
-    /// get a pointer to the value (integer number)
-    constexpr const number_integer_t* get_impl_ptr(const number_integer_t*) const noexcept
-    {
-        return is_number_integer() ? &m_value.number_integer : nullptr;
-    }
-
-    /// get a pointer to the value (unsigned number)
-    number_unsigned_t* get_impl_ptr(number_unsigned_t*) noexcept
-    {
-        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
-    }
-
-    /// get a pointer to the value (unsigned number)
-    constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t*) const noexcept
-    {
-        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
-    }
-
-    /// get a pointer to the value (floating-point number)
-    number_float_t* get_impl_ptr(number_float_t*) noexcept
-    {
-        return is_number_float() ? &m_value.number_float : nullptr;
-    }
-
-    /// get a pointer to the value (floating-point number)
-    constexpr const number_float_t* get_impl_ptr(const number_float_t*) const noexcept
-    {
-        return is_number_float() ? &m_value.number_float : nullptr;
-    }
-
-    /*!
-    @brief helper function to implement get_ref()
-
-    This funcion helps to implement get_ref() without code duplication for
-    const and non-const overloads
-
-    @tparam ThisType will be deduced as `basic_json` or `const basic_json`
-
-    @throw std::domain_error if ReferenceType does not match underlying value
-    type of the current JSON
-    */
-    template<typename ReferenceType, typename ThisType>
-    static ReferenceType get_ref_impl(ThisType& obj)
-    {
-        // helper type
-        using PointerType = typename std::add_pointer<ReferenceType>::type;
-
-        // delegate the call to get_ptr<>()
-        auto ptr = obj.template get_ptr<PointerType>();
-
-        if (ptr != nullptr)
-        {
-            return *ptr;
-        }
-        else
-        {
-            throw std::domain_error("incompatible ReferenceType for get_ref, actual type is " +
-                                    obj.type_name());
-        }
-    }
-
-  public:
-
-    /// @name value access
-    /// Direct access to the stored value of a JSON value.
-    /// @{
-
-    /*!
-    @brief get a value (explicit)
-
-    Explicit type conversion between the JSON value and a compatible value.
-
-    @tparam ValueType non-pointer type compatible to the JSON value, for
-    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
-    `std::vector` types for JSON arrays
-
-    @return copy of the JSON value, converted to type @a ValueType
-
-    @throw std::domain_error in case passed type @a ValueType is incompatible
-    to JSON; example: `"type must be object, but is null"`
-
-    @complexity Linear in the size of the JSON value.
-
-    @liveexample{The example below shows several conversions from JSON values
-    to other types. There a few things to note: (1) Floating-point numbers can
-    be converted to integers\, (2) A JSON array can be converted to a standard
-    `std::vector<short>`\, (3) A JSON object can be converted to C++
-    associative containers such as `std::unordered_map<std::string\,
-    json>`.,get__ValueType_const}
-
-    @internal
-    The idea of using a casted null pointer to choose the correct
-    implementation is from <http://stackoverflow.com/a/8315197/266378>.
-    @endinternal
-
-    @sa @ref operator ValueType() const for implicit conversion
-    @sa @ref get() for pointer-member access
-
-    @since version 1.0.0
-    */
-    template<typename ValueType, typename
-             std::enable_if<
-                 not std::is_pointer<ValueType>::value
-                 , int>::type = 0>
-    ValueType get() const
-    {
-        return get_impl(static_cast<ValueType*>(nullptr));
-    }
-
-    /*!
-    @brief get a pointer value (explicit)
-
-    Explicit pointer access to the internally stored JSON value. No copies are
-    made.
-
-    @warning The pointer becomes invalid if the underlying JSON object
-    changes.
-
-    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
-    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
-    @ref number_unsigned_t, or @ref number_float_t.
-
-    @return pointer to the internally stored JSON value if the requested
-    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how pointers to internal values of a
-    JSON value can be requested. Note that no type conversions are made and a
-    `nullptr` is returned if the value and the requested pointer type does not
-    match.,get__PointerType}
-
-    @sa @ref get_ptr() for explicit pointer-member access
-
-    @since version 1.0.0
-    */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
-    PointerType get() noexcept
-    {
-        // delegate the call to get_ptr
-        return get_ptr<PointerType>();
-    }
-
-    /*!
-    @brief get a pointer value (explicit)
-    @copydoc get()
-    */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
-    constexpr const PointerType get() const noexcept
-    {
-        // delegate the call to get_ptr
-        return get_ptr<PointerType>();
-    }
-
-    /*!
-    @brief get a pointer value (implicit)
-
-    Implicit pointer access to the internally stored JSON value. No copies are
-    made.
-
-    @warning Writing data to the pointee of the result yields an undefined
-    state.
-
-    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
-    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
-    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
-    assertion.
-
-    @return pointer to the internally stored JSON value if the requested
-    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how pointers to internal values of a
-    JSON value can be requested. Note that no type conversions are made and a
-    `nullptr` is returned if the value and the requested pointer type does not
-    match.,get_ptr}
-
-    @since version 1.0.0
-    */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
-    PointerType get_ptr() noexcept
-    {
-        // get the type of the PointerType (remove pointer and const)
-        using pointee_t = typename std::remove_const<typename
-                          std::remove_pointer<typename
-                          std::remove_const<PointerType>::type>::type>::type;
-        // make sure the type matches the allowed types
-        static_assert(
-            std::is_same<object_t, pointee_t>::value
-            or std::is_same<array_t, pointee_t>::value
-            or std::is_same<string_t, pointee_t>::value
-            or std::is_same<boolean_t, pointee_t>::value
-            or std::is_same<number_integer_t, pointee_t>::value
-            or std::is_same<number_unsigned_t, pointee_t>::value
-            or std::is_same<number_float_t, pointee_t>::value
-            , "incompatible pointer type");
-
-        // delegate the call to get_impl_ptr<>()
-        return get_impl_ptr(static_cast<PointerType>(nullptr));
-    }
-
-    /*!
-    @brief get a pointer value (implicit)
-    @copydoc get_ptr()
-    */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 and std::is_const<typename std::remove_pointer<PointerType>::type>::value
-                 , int>::type = 0>
-    constexpr const PointerType get_ptr() const noexcept
-    {
-        // get the type of the PointerType (remove pointer and const)
-        using pointee_t = typename std::remove_const<typename
-                          std::remove_pointer<typename
-                          std::remove_const<PointerType>::type>::type>::type;
-        // make sure the type matches the allowed types
-        static_assert(
-            std::is_same<object_t, pointee_t>::value
-            or std::is_same<array_t, pointee_t>::value
-            or std::is_same<string_t, pointee_t>::value
-            or std::is_same<boolean_t, pointee_t>::value
-            or std::is_same<number_integer_t, pointee_t>::value
-            or std::is_same<number_unsigned_t, pointee_t>::value
-            or std::is_same<number_float_t, pointee_t>::value
-            , "incompatible pointer type");
-
-        // delegate the call to get_impl_ptr<>() const
-        return get_impl_ptr(static_cast<const PointerType>(nullptr));
-    }
-
-    /*!
-    @brief get a reference value (implicit)
-
-    Implict reference access to the internally stored JSON value. No copies
-    are made.
-
-    @warning Writing data to the referee of the result yields an undefined
-    state.
-
-    @tparam ReferenceType reference type; must be a reference to @ref array_t,
-    @ref object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, or
-    @ref number_float_t. Enforced by static assertion.
-
-    @return reference to the internally stored JSON value if the requested
-    reference type @a ReferenceType fits to the JSON value; throws
-    std::domain_error otherwise
-
-    @throw std::domain_error in case passed type @a ReferenceType is
-    incompatible with the stored JSON value
-
-    @complexity Constant.
-
-    @liveexample{The example shows several calls to `get_ref()`.,get_ref}
-
-    @since version 1.1.0
-    */
-    template<typename ReferenceType, typename
-             std::enable_if<
-                 std::is_reference<ReferenceType>::value
-                 , int>::type = 0>
-    ReferenceType get_ref()
-    {
-        // delegate call to get_ref_impl
-        return get_ref_impl<ReferenceType>(*this);
-    }
-
-    /*!
-    @brief get a reference value (implicit)
-    @copydoc get_ref()
-    */
-    template<typename ReferenceType, typename
-             std::enable_if<
-                 std::is_reference<ReferenceType>::value
-                 and std::is_const<typename std::remove_reference<ReferenceType>::type>::value
-                 , int>::type = 0>
-    ReferenceType get_ref() const
-    {
-        // delegate call to get_ref_impl
-        return get_ref_impl<ReferenceType>(*this);
-    }
-
-    /*!
-    @brief get a value (implicit)
-
-    Implicit type conversion between the JSON value and a compatible value.
-    The call is realized by calling @ref get() const.
-
-    @tparam ValueType non-pointer type compatible to the JSON value, for
-    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
-    `std::vector` types for JSON arrays. The character type of @ref string_t
-    as well as an initializer list of this type is excluded to avoid
-    ambiguities as these types implicitly convert to `std::string`.
-
-    @return copy of the JSON value, converted to type @a ValueType
-
-    @throw std::domain_error in case passed type @a ValueType is incompatible
-    to JSON, thrown by @ref get() const
-
-    @complexity Linear in the size of the JSON value.
-
-    @liveexample{The example below shows several conversions from JSON values
-    to other types. There a few things to note: (1) Floating-point numbers can
-    be converted to integers\, (2) A JSON array can be converted to a standard
-    `std::vector<short>`\, (3) A JSON object can be converted to C++
-    associative containers such as `std::unordered_map<std::string\,
-    json>`.,operator__ValueType}
-
-    @since version 1.0.0
-    */
-    template < typename ValueType, typename
-               std::enable_if <
-                   not std::is_pointer<ValueType>::value
-                   and not std::is_same<ValueType, typename string_t::value_type>::value
-#ifndef _MSC_VER  // Fix for issue #167 operator<< abiguity under VS2015
-                   and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
-#endif
-                   , int >::type = 0 >
-    operator ValueType() const
-    {
-        // delegate the call to get<>() const
-        return get<ValueType>();
-    }
-
-    /// @}
-
-
-    ////////////////////
-    // element access //
-    ////////////////////
-
-    /// @name element access
-    /// Access to the JSON value.
-    /// @{
-
-    /*!
-    @brief access specified array element with bounds checking
-
-    Returns a reference to the element at specified location @a idx, with
-    bounds checking.
-
-    @param[in] idx  index of the element to access
-
-    @return reference to the element at index @a idx
-
-    @throw std::domain_error if the JSON value is not an array; example:
-    `"cannot use at() with string"`
-    @throw std::out_of_range if the index @a idx is out of range of the array;
-    that is, `idx >= size()`; example: `"array index 7 is out of range"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how array elements can be read and
-    written using `at()`.,at__size_type}
-
-    @since version 1.0.0
-    */
-    reference at(size_type idx)
-    {
-        // at only works for arrays
-        if (is_array())
-        {
-            try
-            {
-                return m_value.array->at(idx);
-            }
-            catch (std::out_of_range&)
-            {
-                // create better exception explanation
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use at() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified array element with bounds checking
-
-    Returns a const reference to the element at specified location @a idx,
-    with bounds checking.
-
-    @param[in] idx  index of the element to access
-
-    @return const reference to the element at index @a idx
-
-    @throw std::domain_error if the JSON value is not an array; example:
-    `"cannot use at() with string"`
-    @throw std::out_of_range if the index @a idx is out of range of the array;
-    that is, `idx >= size()`; example: `"array index 7 is out of range"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how array elements can be read using
-    `at()`.,at__size_type_const}
-
-    @since version 1.0.0
-    */
-    const_reference at(size_type idx) const
-    {
-        // at only works for arrays
-        if (is_array())
-        {
-            try
-            {
-                return m_value.array->at(idx);
-            }
-            catch (std::out_of_range&)
-            {
-                // create better exception explanation
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use at() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element with bounds checking
-
-    Returns a reference to the element at with specified key @a key, with
-    bounds checking.
-
-    @param[in] key  key of the element to access
-
-    @return reference to the element at key @a key
-
-    @throw std::domain_error if the JSON value is not an object; example:
-    `"cannot use at() with boolean"`
-    @throw std::out_of_range if the key @a key is is not stored in the object;
-    that is, `find(key) == end()`; example: `"key "the fast" not found"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read and
-    written using `at()`.,at__object_t_key_type}
-
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    reference at(const typename object_t::key_type& key)
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            try
-            {
-                return m_value.object->at(key);
-            }
-            catch (std::out_of_range&)
-            {
-                // create better exception explanation
-                throw std::out_of_range("key '" + key + "' not found");
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use at() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element with bounds checking
-
-    Returns a const reference to the element at with specified key @a key,
-    with bounds checking.
-
-    @param[in] key  key of the element to access
-
-    @return const reference to the element at key @a key
-
-    @throw std::domain_error if the JSON value is not an object; example:
-    `"cannot use at() with boolean"`
-    @throw std::out_of_range if the key @a key is is not stored in the object;
-    that is, `find(key) == end()`; example: `"key "the fast" not found"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read using
-    `at()`.,at__object_t_key_type_const}
-
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    const_reference at(const typename object_t::key_type& key) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            try
-            {
-                return m_value.object->at(key);
-            }
-            catch (std::out_of_range&)
-            {
-                // create better exception explanation
-                throw std::out_of_range("key '" + key + "' not found");
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use at() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified array element
-
-    Returns a reference to the element at specified location @a idx.
-
-    @note If @a idx is beyond the range of the array (i.e., `idx >= size()`),
-    then the array is silently filled up with `null` values to make `idx` a
-    valid reference to the last stored element.
-
-    @param[in] idx  index of the element to access
-
-    @return reference to the element at index @a idx
-
-    @throw std::domain_error if JSON is not an array or null; example:
-    `"cannot use operator[] with string"`
-
-    @complexity Constant if @a idx is in the range of the array. Otherwise
-    linear in `idx - size()`.
-
-    @liveexample{The example below shows how array elements can be read and
-    written using `[]` operator. Note the addition of `null`
-    values.,operatorarray__size_type}
-
-    @since version 1.0.0
-    */
-    reference operator[](size_type idx)
-    {
-        // implicitly convert null value to an empty array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value.array = create<array_t>();
-            assert_invariant();
-        }
-
-        // operator[] only works for arrays
-        if (is_array())
-        {
-            // fill up array with null values if given idx is outside range
-            if (idx >= m_value.array->size())
-            {
-                m_value.array->insert(m_value.array->end(),
-                                      idx - m_value.array->size() + 1,
-                                      basic_json());
-            }
-
-            return m_value.array->operator[](idx);
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified array element
-
-    Returns a const reference to the element at specified location @a idx.
-
-    @param[in] idx  index of the element to access
-
-    @return const reference to the element at index @a idx
-
-    @throw std::domain_error if JSON is not an array; example: `"cannot use
-    operator[] with null"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how array elements can be read using
-    the `[]` operator.,operatorarray__size_type_const}
-
-    @since version 1.0.0
-    */
-    const_reference operator[](size_type idx) const
-    {
-        // const operator[] only works for arrays
-        if (is_array())
-        {
-            return m_value.array->operator[](idx);
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element
-
-    Returns a reference to the element at with specified key @a key.
-
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
-
-    @param[in] key  key of the element to access
-
-    @return reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    reference operator[](const typename object_t::key_type& key)
-    {
-        // implicitly convert null value to an empty object
-        if (is_null())
-        {
-            m_type = value_t::object;
-            m_value.object = create<object_t>();
-            assert_invariant();
-        }
-
-        // operator[] only works for objects
-        if (is_object())
-        {
-            return m_value.object->operator[](key);
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief read-only access specified object element
-
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
-
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
-
-    @param[in] key  key of the element to access
-
-    @return const reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    const_reference operator[](const typename object_t::key_type& key) const
-    {
-        // const operator[] only works for objects
-        if (is_object())
-        {
-            assert(m_value.object->find(key) != m_value.object->end());
-            return m_value.object->find(key)->second;
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element
-
-    Returns a reference to the element at with specified key @a key.
-
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
-
-    @param[in] key  key of the element to access
-
-    @return reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    template<typename T, std::size_t n>
-    reference operator[](T * (&key)[n])
-    {
-        return operator[](static_cast<const T>(key));
-    }
-
-    /*!
-    @brief read-only access specified object element
-
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
-
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
-
-    @note This function is required for compatibility reasons with Clang.
-
-    @param[in] key  key of the element to access
-
-    @return const reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.0.0
-    */
-    template<typename T, std::size_t n>
-    const_reference operator[](T * (&key)[n]) const
-    {
-        return operator[](static_cast<const T>(key));
-    }
-
-    /*!
-    @brief access specified object element
-
-    Returns a reference to the element at with specified key @a key.
-
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
-
-    @param[in] key  key of the element to access
-
-    @return reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.1.0
-    */
-    template<typename T>
-    reference operator[](T* key)
-    {
-        // implicitly convert null to object
-        if (is_null())
-        {
-            m_type = value_t::object;
-            m_value = value_t::object;
-            assert_invariant();
-        }
-
-        // at only works for objects
-        if (is_object())
-        {
-            return m_value.object->operator[](key);
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief read-only access specified object element
-
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
-
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
-
-    @param[in] key  key of the element to access
-
-    @return const reference to the element at key @a key
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
-
-    @since version 1.1.0
-    */
-    template<typename T>
-    const_reference operator[](T* key) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            assert(m_value.object->find(key) != m_value.object->end());
-            return m_value.object->find(key)->second;
-        }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
-    }
-
-    /*!
-    @brief access specified object element with default value
-
-    Returns either a copy of an object's element at the specified key @a key
-    or a given default value if no element with key @a key exists.
-
-    The function is basically equivalent to executing
-    @code {.cpp}
-    try {
-        return at(key);
-    } catch(std::out_of_range) {
-        return default_value;
-    }
-    @endcode
-
-    @note Unlike @ref at(const typename object_t::key_type&), this function
-    does not throw if the given key @a key was not found.
-
-    @note Unlike @ref operator[](const typename object_t::key_type& key), this
-    function does not implicitly add an element to the position defined by @a
-    key. This function is furthermore also applicable to const objects.
-
-    @param[in] key  key of the element to access
-    @param[in] default_value  the value to return if @a key is not found
-
-    @tparam ValueType type compatible to JSON values, for instance `int` for
-    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
-    JSON arrays. Note the type of the expected value at @a key and the default
-    value @a default_value must be compatible.
-
-    @return copy of the element at key @a key or @a default_value if @a key
-    is not found
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    value() with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be queried
-    with a default value.,basic_json__value}
-
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
-
-    @since version 1.0.0
-    */
-    template <class ValueType, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, ValueType>::value
-                  , int>::type = 0>
-    ValueType value(const typename object_t::key_type& key, ValueType default_value) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            // if key is found, return value and given default value otherwise
-            const auto it = find(key);
-            if (it != end())
-            {
-                return *it;
-            }
-            else
-            {
-                return default_value;
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use value() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief overload for a default value of type const char*
-    @copydoc basic_json::value(const typename object_t::key_type&, ValueType) const
-    */
-    string_t value(const typename object_t::key_type& key, const char* default_value) const
-    {
-        return value(key, string_t(default_value));
-    }
-
-    /*!
-    @brief access specified object element via JSON Pointer with default value
-
-    Returns either a copy of an object's element at the specified key @a key
-    or a given default value if no element with key @a key exists.
-
-    The function is basically equivalent to executing
-    @code {.cpp}
-    try {
-        return at(ptr);
-    } catch(std::out_of_range) {
-        return default_value;
-    }
-    @endcode
-
-    @note Unlike @ref at(const json_pointer&), this function does not throw
-    if the given key @a key was not found.
-
-    @param[in] ptr  a JSON pointer to the element to access
-    @param[in] default_value  the value to return if @a ptr found no value
-
-    @tparam ValueType type compatible to JSON values, for instance `int` for
-    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
-    JSON arrays. Note the type of the expected value at @a key and the default
-    value @a default_value must be compatible.
-
-    @return copy of the element at key @a key or @a default_value if @a key
-    is not found
-
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    value() with null"`
-
-    @complexity Logarithmic in the size of the container.
-
-    @liveexample{The example below shows how object elements can be queried
-    with a default value.,basic_json__value_ptr}
-
-    @sa @ref operator[](const json_pointer&) for unchecked access by reference
-
-    @since version 2.0.2
-    */
-    template <class ValueType, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, ValueType>::value
-                  , int>::type = 0>
-    ValueType value(const json_pointer& ptr, ValueType default_value) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            // if pointer resolves a value, return it or use default value
-            try
-            {
-                return ptr.get_checked(this);
-            }
-            catch (std::out_of_range&)
-            {
-                return default_value;
-            }
-        }
-        else
-        {
-            throw std::domain_error("cannot use value() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief overload for a default value of type const char*
-    @copydoc basic_json::value(const json_pointer&, ValueType) const
-    */
-    string_t value(const json_pointer& ptr, const char* default_value) const
-    {
-        return value(ptr, string_t(default_value));
-    }
-
-    /*!
-    @brief access the first element
-
-    Returns a reference to the first element in the container. For a JSON
-    container `c`, the expression `c.front()` is equivalent to `*c.begin()`.
-
-    @return In case of a structured type (array or object), a reference to the
-    first element is returned. In cast of number, string, or boolean values, a
-    reference to the value is returned.
-
-    @complexity Constant.
-
-    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
-    or an empty array or object (undefined behavior, guarded by assertions).
-    @post The JSON value remains unchanged.
-
-    @throw std::out_of_range when called on `null` value
-
-    @liveexample{The following code shows an example for `front()`.,front}
-
-    @sa @ref back() -- access the last element
-
-    @since version 1.0.0
-    */
-    reference front()
-    {
-        return *begin();
-    }
-
-    /*!
-    @copydoc basic_json::front()
-    */
-    const_reference front() const
-    {
-        return *cbegin();
-    }
-
-    /*!
-    @brief access the last element
-
-    Returns a reference to the last element in the container. For a JSON
-    container `c`, the expression `c.back()` is equivalent to
-    @code {.cpp}
-    auto tmp = c.end();
-    --tmp;
-    return *tmp;
-    @endcode
-
-    @return In case of a structured type (array or object), a reference to the
-    last element is returned. In cast of number, string, or boolean values, a
-    reference to the value is returned.
-
-    @complexity Constant.
-
-    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
-    or an empty array or object (undefined behavior, guarded by assertions).
-    @post The JSON value remains unchanged.
-
-    @throw std::out_of_range when called on `null` value.
-
-    @liveexample{The following code shows an example for `back()`.,back}
-
-    @sa @ref front() -- access the first element
-
-    @since version 1.0.0
-    */
-    reference back()
-    {
-        auto tmp = end();
-        --tmp;
-        return *tmp;
-    }
-
-    /*!
-    @copydoc basic_json::back()
-    */
-    const_reference back() const
-    {
-        auto tmp = cend();
-        --tmp;
-        return *tmp;
-    }
-
-    /*!
-    @brief remove element given an iterator
-
-    Removes the element specified by iterator @a pos. The iterator @a pos must
-    be valid and dereferenceable. Thus the `end()` iterator (which is valid,
-    but is not dereferenceable) cannot be used as a value for @a pos.
-
-    If called on a primitive type other than `null`, the resulting JSON value
-    will be `null`.
-
-    @param[in] pos iterator to the element to remove
-    @return Iterator following the last removed element. If the iterator @a
-    pos refers to the last element, the `end()` iterator is returned.
-
-    @tparam InteratorType an @ref iterator or @ref const_iterator
-
-    @post Invalidates iterators and references at or after the point of the
-    erase, including the `end()` iterator.
-
-    @throw std::domain_error if called on a `null` value; example: `"cannot
-    use erase() with null"`
-    @throw std::domain_error if called on an iterator which does not belong to
-    the current JSON value; example: `"iterator does not fit current value"`
-    @throw std::out_of_range if called on a primitive type with invalid
-    iterator (i.e., any iterator which is not `begin()`); example: `"iterator
-    out of range"`
-
-    @complexity The complexity depends on the type:
-    - objects: amortized constant
-    - arrays: linear in distance between pos and the end of the container
-    - strings: linear in the length of the string
-    - other types: constant
-
-    @liveexample{The example shows the result of `erase()` for different JSON
-    types.,erase__IteratorType}
-
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
-
-    @since version 1.0.0
-    */
-    template <class InteratorType, typename
-              std::enable_if<
-                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
-                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
-    InteratorType erase(InteratorType pos)
-    {
-        // make sure iterator fits the current value
-        if (this != pos.m_object)
-        {
-            throw std::domain_error("iterator does not fit current value");
-        }
-
-        InteratorType result = end();
-
-        switch (m_type)
-        {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
-            {
-                if (not pos.m_it.primitive_iterator.is_begin())
-                {
-                    throw std::out_of_range("iterator out of range");
-                }
-
-                if (is_string())
-                {
-                    AllocatorType<string_t> alloc;
-                    alloc.destroy(m_value.string);
-                    alloc.deallocate(m_value.string, 1);
-                    m_value.string = nullptr;
-                }
-
-                m_type = value_t::null;
-                assert_invariant();
-                break;
-            }
-
-            case value_t::object:
-            {
-                result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator);
-                break;
-            }
-
-            case value_t::array:
-            {
-                result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator);
-                break;
-            }
-
-            default:
-            {
-                throw std::domain_error("cannot use erase() with " + type_name());
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief remove elements given an iterator range
-
-    Removes the element specified by the range `[first; last)`. The iterator
-    @a first does not need to be dereferenceable if `first == last`: erasing
-    an empty range is a no-op.
-
-    If called on a primitive type other than `null`, the resulting JSON value
-    will be `null`.
-
-    @param[in] first iterator to the beginning of the range to remove
-    @param[in] last iterator past the end of the range to remove
-    @return Iterator following the last removed element. If the iterator @a
-    second refers to the last element, the `end()` iterator is returned.
-
-    @tparam InteratorType an @ref iterator or @ref const_iterator
-
-    @post Invalidates iterators and references at or after the point of the
-    erase, including the `end()` iterator.
-
-    @throw std::domain_error if called on a `null` value; example: `"cannot
-    use erase() with null"`
-    @throw std::domain_error if called on iterators which does not belong to
-    the current JSON value; example: `"iterators do not fit current value"`
-    @throw std::out_of_range if called on a primitive type with invalid
-    iterators (i.e., if `first != begin()` and `last != end()`); example:
-    `"iterators out of range"`
-
-    @complexity The complexity depends on the type:
-    - objects: `log(size()) + std::distance(first, last)`
-    - arrays: linear in the distance between @a first and @a last, plus linear
-      in the distance between @a last and end of the container
-    - strings: linear in the length of the string
-    - other types: constant
-
-    @liveexample{The example shows the result of `erase()` for different JSON
-    types.,erase__IteratorType_IteratorType}
-
-    @sa @ref erase(InteratorType) -- removes the element at a given position
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
-
-    @since version 1.0.0
-    */
-    template <class InteratorType, typename
-              std::enable_if<
-                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
-                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
-    InteratorType erase(InteratorType first, InteratorType last)
-    {
-        // make sure iterator fits the current value
-        if (this != first.m_object or this != last.m_object)
-        {
-            throw std::domain_error("iterators do not fit current value");
-        }
-
-        InteratorType result = end();
-
-        switch (m_type)
-        {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
-            {
-                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
-                {
-                    throw std::out_of_range("iterators out of range");
-                }
-
-                if (is_string())
-                {
-                    AllocatorType<string_t> alloc;
-                    alloc.destroy(m_value.string);
-                    alloc.deallocate(m_value.string, 1);
-                    m_value.string = nullptr;
-                }
-
-                m_type = value_t::null;
-                assert_invariant();
-                break;
-            }
-
-            case value_t::object:
-            {
-                result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator,
-                                              last.m_it.object_iterator);
-                break;
-            }
-
-            case value_t::array:
-            {
-                result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator,
-                                             last.m_it.array_iterator);
-                break;
-            }
-
-            default:
-            {
-                throw std::domain_error("cannot use erase() with " + type_name());
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief remove element from a JSON object given a key
-
-    Removes elements from a JSON object with the key value @a key.
-
-    @param[in] key value of the elements to remove
-
-    @return Number of elements removed. If @a ObjectType is the default
-    `std::map` type, the return value will always be `0` (@a key was not
-    found) or `1` (@a key was found).
-
-    @post References and iterators to the erased elements are invalidated.
-    Other references and iterators are not affected.
-
-    @throw std::domain_error when called on a type other than JSON object;
-    example: `"cannot use erase() with null"`
-
-    @complexity `log(size()) + count(key)`
-
-    @liveexample{The example shows the effect of `erase()`.,erase__key_type}
-
-    @sa @ref erase(InteratorType) -- removes the element at a given position
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
-
-    @since version 1.0.0
-    */
-    size_type erase(const typename object_t::key_type& key)
-    {
-        // this erase only works for objects
-        if (is_object())
-        {
-            return m_value.object->erase(key);
-        }
-        else
-        {
-            throw std::domain_error("cannot use erase() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief remove element from a JSON array given an index
-
-    Removes element from a JSON array at the index @a idx.
-
-    @param[in] idx index of the element to remove
-
-    @throw std::domain_error when called on a type other than JSON array;
-    example: `"cannot use erase() with null"`
-    @throw std::out_of_range when `idx >= size()`; example: `"array index 17
-    is out of range"`
-
-    @complexity Linear in distance between @a idx and the end of the container.
-
-    @liveexample{The example shows the effect of `erase()`.,erase__size_type}
-
-    @sa @ref erase(InteratorType) -- removes the element at a given position
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-
-    @since version 1.0.0
-    */
-    void erase(const size_type idx)
-    {
-        // this erase only works for arrays
-        if (is_array())
-        {
-            if (idx >= size())
-            {
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
-            }
-
-            m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
-        }
-        else
-        {
-            throw std::domain_error("cannot use erase() with " + type_name());
-        }
-    }
-
-    /// @}
-
-
-    ////////////
-    // lookup //
-    ////////////
-
-    /// @name lookup
-    /// @{
-
-    /*!
-    @brief find an element in a JSON object
-
-    Finds an element in a JSON object with key equivalent to @a key. If the
-    element is not found or the JSON value is not an object, end() is
-    returned.
-
-    @param[in] key key value of the element to search for
-
-    @return Iterator to an element with key equivalent to @a key. If no such
-    element is found, past-the-end (see end()) iterator is returned.
-
-    @complexity Logarithmic in the size of the JSON object.
-
-    @liveexample{The example shows how `find()` is used.,find__key_type}
-
-    @since version 1.0.0
-    */
-    iterator find(typename object_t::key_type key)
-    {
-        auto result = end();
-
-        if (is_object())
-        {
-            result.m_it.object_iterator = m_value.object->find(key);
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief find an element in a JSON object
-    @copydoc find(typename object_t::key_type)
-    */
-    const_iterator find(typename object_t::key_type key) const
-    {
-        auto result = cend();
-
-        if (is_object())
-        {
-            result.m_it.object_iterator = m_value.object->find(key);
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief returns the number of occurrences of a key in a JSON object
-
-    Returns the number of elements with key @a key. If ObjectType is the
-    default `std::map` type, the return value will always be `0` (@a key was
-    not found) or `1` (@a key was found).
-
-    @param[in] key key value of the element to count
-
-    @return Number of elements with key @a key. If the JSON value is not an
-    object, the return value will be `0`.
-
-    @complexity Logarithmic in the size of the JSON object.
-
-    @liveexample{The example shows how `count()` is used.,count}
-
-    @since version 1.0.0
-    */
-    size_type count(typename object_t::key_type key) const
-    {
-        // return 0 for all nonobject types
-        return is_object() ? m_value.object->count(key) : 0;
-    }
-
-    /// @}
-
-
-    ///////////////
-    // iterators //
-    ///////////////
-
-    /// @name iterators
-    /// @{
-
-    /*!
-    @brief returns an iterator to the first element
-
-    Returns an iterator to the first element.
-
-    @image html range-begin-end.svg "Illustration from cppreference.com"
-
-    @return iterator to the first element
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-
-    @liveexample{The following code shows an example for `begin()`.,begin}
-
-    @sa @ref cbegin() -- returns a const iterator to the beginning
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref cend() -- returns a const iterator to the end
-
-    @since version 1.0.0
-    */
-    iterator begin() noexcept
-    {
-        iterator result(this);
-        result.set_begin();
-        return result;
-    }
-
-    /*!
-    @copydoc basic_json::cbegin()
-    */
-    const_iterator begin() const noexcept
-    {
-        return cbegin();
-    }
-
-    /*!
-    @brief returns a const iterator to the first element
-
-    Returns a const iterator to the first element.
-
-    @image html range-begin-end.svg "Illustration from cppreference.com"
-
-    @return const iterator to the first element
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).begin()`.
-
-    @liveexample{The following code shows an example for `cbegin()`.,cbegin}
-
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref cend() -- returns a const iterator to the end
-
-    @since version 1.0.0
-    */
-    const_iterator cbegin() const noexcept
-    {
-        const_iterator result(this);
-        result.set_begin();
-        return result;
-    }
-
-    /*!
-    @brief returns an iterator to one past the last element
-
-    Returns an iterator to one past the last element.
-
-    @image html range-begin-end.svg "Illustration from cppreference.com"
-
-    @return iterator one past the last element
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-
-    @liveexample{The following code shows an example for `end()`.,end}
-
-    @sa @ref cend() -- returns a const iterator to the end
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref cbegin() -- returns a const iterator to the beginning
-
-    @since version 1.0.0
-    */
-    iterator end() noexcept
-    {
-        iterator result(this);
-        result.set_end();
-        return result;
-    }
-
-    /*!
-    @copydoc basic_json::cend()
-    */
-    const_iterator end() const noexcept
-    {
-        return cend();
-    }
-
-    /*!
-    @brief returns a const iterator to one past the last element
-
-    Returns a const iterator to one past the last element.
-
-    @image html range-begin-end.svg "Illustration from cppreference.com"
-
-    @return const iterator one past the last element
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).end()`.
-
-    @liveexample{The following code shows an example for `cend()`.,cend}
-
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref cbegin() -- returns a const iterator to the beginning
-
-    @since version 1.0.0
-    */
-    const_iterator cend() const noexcept
-    {
-        const_iterator result(this);
-        result.set_end();
-        return result;
-    }
-
-    /*!
-    @brief returns an iterator to the reverse-beginning
-
-    Returns an iterator to the reverse-beginning; that is, the last element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `reverse_iterator(end())`.
-
-    @liveexample{The following code shows an example for `rbegin()`.,rbegin}
-
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref crend() -- returns a const reverse iterator to the end
-
-    @since version 1.0.0
-    */
-    reverse_iterator rbegin() noexcept
-    {
-        return reverse_iterator(end());
-    }
-
-    /*!
-    @copydoc basic_json::crbegin()
-    */
-    const_reverse_iterator rbegin() const noexcept
-    {
-        return crbegin();
-    }
-
-    /*!
-    @brief returns an iterator to the reverse-end
-
-    Returns an iterator to the reverse-end; that is, one before the first
-    element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `reverse_iterator(begin())`.
-
-    @liveexample{The following code shows an example for `rend()`.,rend}
-
-    @sa @ref crend() -- returns a const reverse iterator to the end
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
-
-    @since version 1.0.0
-    */
-    reverse_iterator rend() noexcept
-    {
-        return reverse_iterator(begin());
-    }
-
-    /*!
-    @copydoc basic_json::crend()
-    */
-    const_reverse_iterator rend() const noexcept
-    {
-        return crend();
-    }
-
-    /*!
-    @brief returns a const reverse iterator to the last element
-
-    Returns a const iterator to the reverse-beginning; that is, the last
-    element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).rbegin()`.
-
-    @liveexample{The following code shows an example for `crbegin()`.,crbegin}
-
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref crend() -- returns a const reverse iterator to the end
-
-    @since version 1.0.0
-    */
-    const_reverse_iterator crbegin() const noexcept
-    {
-        return const_reverse_iterator(cend());
-    }
-
-    /*!
-    @brief returns a const reverse iterator to one before the first
-
-    Returns a const reverse iterator to the reverse-end; that is, one before
-    the first element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
-
-    @complexity Constant.
-
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).rend()`.
-
-    @liveexample{The following code shows an example for `crend()`.,crend}
-
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
-
-    @since version 1.0.0
-    */
-    const_reverse_iterator crend() const noexcept
-    {
-        return const_reverse_iterator(cbegin());
-    }
-
-  private:
-    // forward declaration
-    template<typename IteratorType> class iteration_proxy;
-
-  public:
-    /*!
-    @brief wrapper to access iterator member functions in range-based for
-
-    This function allows to access @ref iterator::key() and @ref
-    iterator::value() during range-based for loops. In these loops, a
-    reference to the JSON values is returned, so there is no access to the
-    underlying iterator.
-
-    @note The name of this function is not yet final and may change in the
-    future.
-    */
-    static iteration_proxy<iterator> iterator_wrapper(reference cont)
-    {
-        return iteration_proxy<iterator>(cont);
-    }
-
-    /*!
-    @copydoc iterator_wrapper(reference)
-    */
-    static iteration_proxy<const_iterator> iterator_wrapper(const_reference cont)
-    {
-        return iteration_proxy<const_iterator>(cont);
-    }
-
-    /// @}
-
-
-    //////////////
-    // capacity //
-    //////////////
-
-    /// @name capacity
-    /// @{
-
-    /*!
-    @brief checks whether the container is empty
-
-    Checks if a JSON value has no elements.
-
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `true`
-            boolean     | `false`
-            string      | `false`
-            number      | `false`
-            object      | result of function `object_t::empty()`
-            array       | result of function `array_t::empty()`
-
-    @note This function does not return whether a string stored as JSON value
-    is empty - it returns whether the JSON container itself is empty which is
-    false in the case of a string.
-
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their `empty()` functions have constant
-    complexity.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `begin() == end()`.
-
-    @liveexample{The following code uses `empty()` to check if a JSON
-    object contains any elements.,empty}
-
-    @sa @ref size() -- returns the number of elements
-
-    @since version 1.0.0
-    */
-    bool empty() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-            {
-                // null values are empty
-                return true;
-            }
-
-            case value_t::array:
-            {
-                // delegate call to array_t::empty()
-                return m_value.array->empty();
-            }
-
-            case value_t::object:
-            {
-                // delegate call to object_t::empty()
-                return m_value.object->empty();
-            }
-
-            default:
-            {
-                // all other types are nonempty
-                return false;
-            }
-        }
-    }
-
-    /*!
-    @brief returns the number of elements
-
-    Returns the number of elements in a JSON value.
-
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `0`
-            boolean     | `1`
-            string      | `1`
-            number      | `1`
-            object      | result of function object_t::size()
-            array       | result of function array_t::size()
-
-    @note This function does not return the length of a string stored as JSON
-    value - it returns the number of elements in the JSON value which is 1 in
-    the case of a string.
-
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their size() functions have constant
-    complexity.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `std::distance(begin(), end())`.
-
-    @liveexample{The following code calls `size()` on the different value
-    types.,size}
-
-    @sa @ref empty() -- checks whether the container is empty
-    @sa @ref max_size() -- returns the maximal number of elements
-
-    @since version 1.0.0
-    */
-    size_type size() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-            {
-                // null values are empty
-                return 0;
-            }
-
-            case value_t::array:
-            {
-                // delegate call to array_t::size()
-                return m_value.array->size();
-            }
-
-            case value_t::object:
-            {
-                // delegate call to object_t::size()
-                return m_value.object->size();
-            }
-
-            default:
-            {
-                // all other types have size 1
-                return 1;
-            }
-        }
-    }
-
-    /*!
-    @brief returns the maximum possible number of elements
-
-    Returns the maximum number of elements a JSON value is able to hold due to
-    system or library implementation limitations, i.e. `std::distance(begin(),
-    end())` for the JSON value.
-
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `0` (same as `size()`)
-            boolean     | `1` (same as `size()`)
-            string      | `1` (same as `size()`)
-            number      | `1` (same as `size()`)
-            object      | result of function `object_t::max_size()`
-            array       | result of function `array_t::max_size()`
-
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their `max_size()` functions have constant
-    complexity.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of returning `b.size()` where `b` is the largest
-      possible JSON value.
-
-    @liveexample{The following code calls `max_size()` on the different value
-    types. Note the output is implementation specific.,max_size}
-
-    @sa @ref size() -- returns the number of elements
-
-    @since version 1.0.0
-    */
-    size_type max_size() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::array:
-            {
-                // delegate call to array_t::max_size()
-                return m_value.array->max_size();
-            }
-
-            case value_t::object:
-            {
-                // delegate call to object_t::max_size()
-                return m_value.object->max_size();
-            }
-
-            default:
-            {
-                // all other types have max_size() == size()
-                return size();
-            }
-        }
-    }
-
-    /// @}
-
-
-    ///////////////
-    // modifiers //
-    ///////////////
-
-    /// @name modifiers
-    /// @{
-
-    /*!
-    @brief clears the contents
-
-    Clears the content of a JSON value and resets it to the default value as
-    if @ref basic_json(value_t) would have been called:
-
-    Value type  | initial value
-    ----------- | -------------
-    null        | `null`
-    boolean     | `false`
-    string      | `""`
-    number      | `0`
-    object      | `{}`
-    array       | `[]`
-
-    @note Floating-point numbers are set to `0.0` which will be serialized to
-    `0`. The vale type remains @ref number_float_t.
-
-    @complexity Linear in the size of the JSON value.
-
-    @liveexample{The example below shows the effect of `clear()` to different
-    JSON types.,clear}
-
-    @since version 1.0.0
-    */
-    void clear() noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::number_integer:
-            {
-                m_value.number_integer = 0;
-                break;
-            }
-
-            case value_t::number_unsigned:
-            {
-                m_value.number_unsigned = 0;
-                break;
-            }
-
-            case value_t::number_float:
-            {
-                m_value.number_float = 0.0;
-                break;
-            }
-
-            case value_t::boolean:
-            {
-                m_value.boolean = false;
-                break;
-            }
-
-            case value_t::string:
-            {
-                m_value.string->clear();
-                break;
-            }
-
-            case value_t::array:
-            {
-                m_value.array->clear();
-                break;
-            }
-
-            case value_t::object:
-            {
-                m_value.object->clear();
-                break;
-            }
-
-            default:
-            {
-                break;
-            }
-        }
-    }
-
-    /*!
-    @brief add an object to an array
-
-    Appends the given element @a val to the end of the JSON value. If the
-    function is called on a JSON null value, an empty array is created before
-    appending @a val.
-
-    @param[in] val the value to add to the JSON array
-
-    @throw std::domain_error when called on a type other than JSON array or
-    null; example: `"cannot use push_back() with number"`
-
-    @complexity Amortized constant.
-
-    @liveexample{The example shows how `push_back()` and `+=` can be used to
-    add elements to a JSON array. Note how the `null` value was silently
-    converted to a JSON array.,push_back}
-
-    @since version 1.0.0
-    */
-    void push_back(basic_json&& val)
-    {
-        // push_back only works for null objects or arrays
-        if (not(is_null() or is_array()))
-        {
-            throw std::domain_error("cannot use push_back() with " + type_name());
-        }
-
-        // transform null object into an array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value = value_t::array;
-            assert_invariant();
-        }
-
-        // add element to array (move semantics)
-        m_value.array->push_back(std::move(val));
-        // invalidate object
-        val.m_type = value_t::null;
-    }
-
-    /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
-    */
-    reference operator+=(basic_json&& val)
-    {
-        push_back(std::move(val));
-        return *this;
-    }
-
-    /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
-    */
-    void push_back(const basic_json& val)
-    {
-        // push_back only works for null objects or arrays
-        if (not(is_null() or is_array()))
-        {
-            throw std::domain_error("cannot use push_back() with " + type_name());
-        }
-
-        // transform null object into an array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value = value_t::array;
-            assert_invariant();
-        }
-
-        // add element to array
-        m_value.array->push_back(val);
-    }
-
-    /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
-    */
-    reference operator+=(const basic_json& val)
-    {
-        push_back(val);
-        return *this;
-    }
-
-    /*!
-    @brief add an object to an object
-
-    Inserts the given element @a val to the JSON object. If the function is
-    called on a JSON null value, an empty object is created before inserting
-    @a val.
-
-    @param[in] val the value to add to the JSON object
-
-    @throw std::domain_error when called on a type other than JSON object or
-    null; example: `"cannot use push_back() with number"`
-
-    @complexity Logarithmic in the size of the container, O(log(`size()`)).
-
-    @liveexample{The example shows how `push_back()` and `+=` can be used to
-    add elements to a JSON object. Note how the `null` value was silently
-    converted to a JSON object.,push_back__object_t__value}
-
-    @since version 1.0.0
-    */
-    void push_back(const typename object_t::value_type& val)
-    {
-        // push_back only works for null objects or objects
-        if (not(is_null() or is_object()))
-        {
-            throw std::domain_error("cannot use push_back() with " + type_name());
-        }
-
-        // transform null object into an object
-        if (is_null())
-        {
-            m_type = value_t::object;
-            m_value = value_t::object;
-            assert_invariant();
-        }
-
-        // add element to array
-        m_value.object->insert(val);
-    }
-
-    /*!
-    @brief add an object to an object
-    @copydoc push_back(const typename object_t::value_type&)
-    */
-    reference operator+=(const typename object_t::value_type& val)
-    {
-        push_back(val);
-        return *this;
-    }
-
-    /*!
-    @brief add an object to an object
-
-    This function allows to use `push_back` with an initializer list. In case
-
-    1. the current value is an object,
-    2. the initializer list @a init contains only two elements, and
-    3. the first element of @a init is a string,
-
-    @a init is converted into an object element and added using
-    @ref push_back(const typename object_t::value_type&). Otherwise, @a init
-    is converted to a JSON value and added using @ref push_back(basic_json&&).
-
-    @param init  an initializer list
-
-    @complexity Linear in the size of the initializer list @a init.
-
-    @note This function is required to resolve an ambiguous overload error,
-          because pairs like `{"key", "value"}` can be both interpreted as
-          `object_t::value_type` or `std::initializer_list<basic_json>`, see
-          https://github.com/nlohmann/json/issues/235 for more information.
-
-    @liveexample{The example shows how initializer lists are treated as
-    objects when possible.,push_back__initializer_list}
-    */
-    void push_back(std::initializer_list<basic_json> init)
-    {
-        if (is_object() and init.size() == 2 and init.begin()->is_string())
-        {
-            const string_t key = *init.begin();
-            push_back(typename object_t::value_type(key, *(init.begin() + 1)));
-        }
-        else
-        {
-            push_back(basic_json(init));
-        }
-    }
-
-    /*!
-    @brief add an object to an object
-    @copydoc push_back(std::initializer_list<basic_json>)
-    */
-    reference operator+=(std::initializer_list<basic_json> init)
-    {
-        push_back(init);
-        return *this;
-    }
-
-    /*!
-    @brief inserts element
-
-    Inserts element @a val before iterator @a pos.
-
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] val element to insert
-    @return iterator pointing to the inserted @a val.
-
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-
-    @complexity Constant plus linear in the distance between pos and end of the
-    container.
-
-    @liveexample{The example shows how `insert()` is used.,insert}
-
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, const basic_json& val)
-    {
-        // insert only works for arrays
-        if (is_array())
-        {
-            // check if iterator pos fits to this JSON value
-            if (pos.m_object != this)
-            {
-                throw std::domain_error("iterator does not fit current value");
-            }
-
-            // insert to array and return iterator
-            iterator result(this);
-            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
-            return result;
-        }
-        else
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief inserts element
-    @copydoc insert(const_iterator, const basic_json&)
-    */
-    iterator insert(const_iterator pos, basic_json&& val)
-    {
-        return insert(pos, val);
-    }
-
-    /*!
-    @brief inserts elements
-
-    Inserts @a cnt copies of @a val before iterator @a pos.
-
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] cnt number of copies of @a val to insert
-    @param[in] val element to insert
-    @return iterator pointing to the first element inserted, or @a pos if
-    `cnt==0`
-
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-
-    @complexity Linear in @a cnt plus linear in the distance between @a pos
-    and end of the container.
-
-    @liveexample{The example shows how `insert()` is used.,insert__count}
-
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, size_type cnt, const basic_json& val)
-    {
-        // insert only works for arrays
-        if (is_array())
-        {
-            // check if iterator pos fits to this JSON value
-            if (pos.m_object != this)
-            {
-                throw std::domain_error("iterator does not fit current value");
-            }
-
-            // insert to array and return iterator
-            iterator result(this);
-            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
-            return result;
-        }
-        else
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief inserts elements
-
-    Inserts elements from range `[first, last)` before iterator @a pos.
-
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] first begin of the range of elements to insert
-    @param[in] last end of the range of elements to insert
-
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-    @throw std::domain_error if @a first and @a last do not belong to the same
-    JSON value; example: `"iterators do not fit"`
-    @throw std::domain_error if @a first or @a last are iterators into
-    container for which insert is called; example: `"passed iterators may not
-    belong to container"`
-
-    @return iterator pointing to the first element inserted, or @a pos if
-    `first==last`
-
-    @complexity Linear in `std::distance(first, last)` plus linear in the
-    distance between @a pos and end of the container.
-
-    @liveexample{The example shows how `insert()` is used.,insert__range}
-
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, const_iterator first, const_iterator last)
-    {
-        // insert only works for arrays
-        if (not is_array())
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
-
-        // check if iterator pos fits to this JSON value
-        if (pos.m_object != this)
-        {
-            throw std::domain_error("iterator does not fit current value");
-        }
-
-        // check if range iterators belong to the same JSON object
-        if (first.m_object != last.m_object)
-        {
-            throw std::domain_error("iterators do not fit");
-        }
-
-        if (first.m_object == this or last.m_object == this)
-        {
-            throw std::domain_error("passed iterators may not belong to container");
-        }
-
-        // insert to array and return iterator
-        iterator result(this);
-        result.m_it.array_iterator = m_value.array->insert(
-                                         pos.m_it.array_iterator,
-                                         first.m_it.array_iterator,
-                                         last.m_it.array_iterator);
-        return result;
-    }
-
-    /*!
-    @brief inserts elements
-
-    Inserts elements from initializer list @a ilist before iterator @a pos.
-
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] ilist initializer list to insert the values from
-
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-
-    @return iterator pointing to the first element inserted, or @a pos if
-    `ilist` is empty
-
-    @complexity Linear in `ilist.size()` plus linear in the distance between
-    @a pos and end of the container.
-
-    @liveexample{The example shows how `insert()` is used.,insert__ilist}
-
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, std::initializer_list<basic_json> ilist)
-    {
-        // insert only works for arrays
-        if (not is_array())
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
-
-        // check if iterator pos fits to this JSON value
-        if (pos.m_object != this)
-        {
-            throw std::domain_error("iterator does not fit current value");
-        }
-
-        // insert to array and return iterator
-        iterator result(this);
-        result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, ilist);
-        return result;
-    }
-
-    /*!
-    @brief exchanges the values
-
-    Exchanges the contents of the JSON value with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
-
-    @param[in,out] other JSON value to exchange the contents with
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how JSON values can be swapped with
-    `swap()`.,swap__reference}
-
-    @since version 1.0.0
-    */
-    void swap(reference other) noexcept (
-        std::is_nothrow_move_constructible<value_t>::value and
-        std::is_nothrow_move_assignable<value_t>::value and
-        std::is_nothrow_move_constructible<json_value>::value and
-        std::is_nothrow_move_assignable<json_value>::value
-    )
-    {
-        std::swap(m_type, other.m_type);
-        std::swap(m_value, other.m_value);
-        assert_invariant();
-    }
-
-    /*!
-    @brief exchanges the values
-
-    Exchanges the contents of a JSON array with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
-
-    @param[in,out] other array to exchange the contents with
-
-    @throw std::domain_error when JSON value is not an array; example: `"cannot
-    use swap() with string"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how arrays can be swapped with
-    `swap()`.,swap__array_t}
-
-    @since version 1.0.0
-    */
-    void swap(array_t& other)
-    {
-        // swap only works for arrays
-        if (is_array())
-        {
-            std::swap(*(m_value.array), other);
-        }
-        else
-        {
-            throw std::domain_error("cannot use swap() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief exchanges the values
-
-    Exchanges the contents of a JSON object with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
-
-    @param[in,out] other object to exchange the contents with
-
-    @throw std::domain_error when JSON value is not an object; example:
-    `"cannot use swap() with string"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how objects can be swapped with
-    `swap()`.,swap__object_t}
-
-    @since version 1.0.0
-    */
-    void swap(object_t& other)
-    {
-        // swap only works for objects
-        if (is_object())
-        {
-            std::swap(*(m_value.object), other);
-        }
-        else
-        {
-            throw std::domain_error("cannot use swap() with " + type_name());
-        }
-    }
-
-    /*!
-    @brief exchanges the values
-
-    Exchanges the contents of a JSON string with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
-
-    @param[in,out] other string to exchange the contents with
-
-    @throw std::domain_error when JSON value is not a string; example: `"cannot
-    use swap() with boolean"`
-
-    @complexity Constant.
-
-    @liveexample{The example below shows how strings can be swapped with
-    `swap()`.,swap__string_t}
-
-    @since version 1.0.0
-    */
-    void swap(string_t& other)
-    {
-        // swap only works for strings
-        if (is_string())
-        {
-            std::swap(*(m_value.string), other);
-        }
-        else
-        {
-            throw std::domain_error("cannot use swap() with " + type_name());
-        }
-    }
-
-    /// @}
-
-
-    //////////////////////////////////////////
-    // lexicographical comparison operators //
-    //////////////////////////////////////////
-
-    /// @name lexicographical comparison operators
-    /// @{
-
-  private:
-    /*!
-    @brief comparison operator for JSON types
-
-    Returns an ordering that is similar to Python:
-    - order: null < boolean < number < object < array < string
-    - furthermore, each type is not smaller than itself
-
-    @since version 1.0.0
-    */
-    friend bool operator<(const value_t lhs, const value_t rhs) noexcept
-    {
-        static constexpr std::array<uint8_t, 8> order = {{
-                0, // null
-                3, // object
-                4, // array
-                5, // string
-                1, // boolean
-                2, // integer
-                2, // unsigned
-                2, // float
-            }
-        };
-
-        // discarded values are not comparable
-        if (lhs == value_t::discarded or rhs == value_t::discarded)
-        {
-            return false;
-        }
-
-        return order[static_cast<std::size_t>(lhs)] < order[static_cast<std::size_t>(rhs)];
-    }
-
-  public:
-    /*!
-    @brief comparison: equal
-
-    Compares two JSON values for equality according to the following rules:
-    - Two JSON values are equal if (1) they are from the same type and (2)
-      their stored values are the same.
-    - Integer and floating-point numbers are automatically converted before
-      comparison. Floating-point numbers are compared indirectly: two
-      floating-point numbers `f1` and `f2` are considered equal if neither
-      `f1 > f2` nor `f2 > f1` holds.
-    - Two JSON null values are equal.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether the values @a lhs and @a rhs are equal
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__equal}
-
-    @since version 1.0.0
-    */
-    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
-    {
-        const auto lhs_type = lhs.type();
-        const auto rhs_type = rhs.type();
-
-        if (lhs_type == rhs_type)
-        {
-            switch (lhs_type)
-            {
-                case value_t::array:
-                {
-                    return *lhs.m_value.array == *rhs.m_value.array;
-                }
-                case value_t::object:
-                {
-                    return *lhs.m_value.object == *rhs.m_value.object;
-                }
-                case value_t::null:
-                {
-                    return true;
-                }
-                case value_t::string:
-                {
-                    return *lhs.m_value.string == *rhs.m_value.string;
-                }
-                case value_t::boolean:
-                {
-                    return lhs.m_value.boolean == rhs.m_value.boolean;
-                }
-                case value_t::number_integer:
-                {
-                    return lhs.m_value.number_integer == rhs.m_value.number_integer;
-                }
-                case value_t::number_unsigned:
-                {
-                    return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned;
-                }
-                case value_t::number_float:
-                {
-                    return lhs.m_value.number_float == rhs.m_value.number_float;
-                }
-                default:
-                {
-                    return false;
-                }
-            }
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
-        {
-            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
-        {
-            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer;
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned);
-        }
-
-        return false;
-    }
-
-    /*!
-    @brief comparison: equal
-
-    The functions compares the given JSON value against a null pointer. As the
-    null pointer can be used to initialize a JSON value to null, a comparison
-    of JSON value @a v with a null pointer should be equivalent to call
-    `v.is_null()`.
-
-    @param[in] v  JSON value to consider
-    @return whether @a v is null
-
-    @complexity Constant.
-
-    @liveexample{The example compares several JSON types to the null pointer.
-    ,operator__equal__nullptr_t}
-
-    @since version 1.0.0
-    */
-    friend bool operator==(const_reference v, std::nullptr_t) noexcept
-    {
-        return v.is_null();
-    }
-
-    /*!
-    @brief comparison: equal
-    @copydoc operator==(const_reference, std::nullptr_t)
-    */
-    friend bool operator==(std::nullptr_t, const_reference v) noexcept
-    {
-        return v.is_null();
-    }
-
-    /*!
-    @brief comparison: not equal
-
-    Compares two JSON values for inequality by calculating `not (lhs == rhs)`.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether the values @a lhs and @a rhs are not equal
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__notequal}
-
-    @since version 1.0.0
-    */
-    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs == rhs);
-    }
-
-    /*!
-    @brief comparison: not equal
-
-    The functions compares the given JSON value against a null pointer. As the
-    null pointer can be used to initialize a JSON value to null, a comparison
-    of JSON value @a v with a null pointer should be equivalent to call
-    `not v.is_null()`.
-
-    @param[in] v  JSON value to consider
-    @return whether @a v is not null
-
-    @complexity Constant.
-
-    @liveexample{The example compares several JSON types to the null pointer.
-    ,operator__notequal__nullptr_t}
-
-    @since version 1.0.0
-    */
-    friend bool operator!=(const_reference v, std::nullptr_t) noexcept
-    {
-        return not v.is_null();
-    }
-
-    /*!
-    @brief comparison: not equal
-    @copydoc operator!=(const_reference, std::nullptr_t)
-    */
-    friend bool operator!=(std::nullptr_t, const_reference v) noexcept
-    {
-        return not v.is_null();
-    }
-
-    /*!
-    @brief comparison: less than
-
-    Compares whether one JSON value @a lhs is less than another JSON value @a
-    rhs according to the following rules:
-    - If @a lhs and @a rhs have the same type, the values are compared using
-      the default `<` operator.
-    - Integer and floating-point numbers are automatically converted before
-      comparison
-    - In case @a lhs and @a rhs have different types, the values are ignored
-      and the order of the types is considered, see
-      @ref operator<(const value_t, const value_t).
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is less than @a rhs
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__less}
-
-    @since version 1.0.0
-    */
-    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
-    {
-        const auto lhs_type = lhs.type();
-        const auto rhs_type = rhs.type();
-
-        if (lhs_type == rhs_type)
-        {
-            switch (lhs_type)
-            {
-                case value_t::array:
-                {
-                    return *lhs.m_value.array < *rhs.m_value.array;
-                }
-                case value_t::object:
-                {
-                    return *lhs.m_value.object < *rhs.m_value.object;
-                }
-                case value_t::null:
-                {
-                    return false;
-                }
-                case value_t::string:
-                {
-                    return *lhs.m_value.string < *rhs.m_value.string;
-                }
-                case value_t::boolean:
-                {
-                    return lhs.m_value.boolean < rhs.m_value.boolean;
-                }
-                case value_t::number_integer:
-                {
-                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
-                }
-                case value_t::number_unsigned:
-                {
-                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
-                }
-                case value_t::number_float:
-                {
-                    return lhs.m_value.number_float < rhs.m_value.number_float;
-                }
-                default:
-                {
-                    return false;
-                }
-            }
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
-        {
-            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
-        {
-            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
-        }
-
-        // We only reach this line if we cannot compare values. In that case,
-        // we compare types. Note we have to call the operator explicitly,
-        // because MSVC has problems otherwise.
-        return operator<(lhs_type, rhs_type);
-    }
-
-    /*!
-    @brief comparison: less than or equal
-
-    Compares whether one JSON value @a lhs is less than or equal to another
-    JSON value by calculating `not (rhs < lhs)`.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is less than or equal to @a rhs
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__greater}
-
-    @since version 1.0.0
-    */
-    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (rhs < lhs);
-    }
-
-    /*!
-    @brief comparison: greater than
-
-    Compares whether one JSON value @a lhs is greater than another
-    JSON value by calculating `not (lhs <= rhs)`.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is greater than to @a rhs
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__lessequal}
-
-    @since version 1.0.0
-    */
-    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs <= rhs);
-    }
-
-    /*!
-    @brief comparison: greater than or equal
-
-    Compares whether one JSON value @a lhs is greater than or equal to another
-    JSON value by calculating `not (lhs < rhs)`.
-
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is greater than or equal to @a rhs
-
-    @complexity Linear.
-
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__greaterequal}
-
-    @since version 1.0.0
-    */
-    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs < rhs);
-    }
-
-    /// @}
-
-
-    ///////////////////
-    // serialization //
-    ///////////////////
-
-    /// @name serialization
-    /// @{
-
-    /*!
-    @brief serialize to stream
-
-    Serialize the given JSON value @a j to the output stream @a o. The JSON
-    value will be serialized using the @ref dump member function. The
-    indentation of the output can be controlled with the member variable
-    `width` of the output stream @a o. For instance, using the manipulator
-    `std::setw(4)` on @a o sets the indentation level to `4` and the
-    serialization result is the same as calling `dump(4)`.
-
-    @note During serializaion, the locale and the precision of the output
-    stream @a o are changed. The original values are restored when the
-    function returns.
-
-    @param[in,out] o  stream to serialize to
-    @param[in] j  JSON value to serialize
-
-    @return the stream @a o
-
-    @complexity Linear.
-
-    @liveexample{The example below shows the serialization with different
-    parameters to `width` to adjust the indentation level.,operator_serialize}
-
-    @since version 1.0.0
-    */
-    friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
-    {
-        // read width member and use it as indentation parameter if nonzero
-        const bool pretty_print = (o.width() > 0);
-        const auto indentation = (pretty_print ? o.width() : 0);
-
-        // reset width to 0 for subsequent calls to this stream
-        o.width(0);
-
-        // fix locale problems
-        const auto old_locale = o.imbue(std::locale(std::locale(), new DecimalSeparator));
-        // set precision
-
-        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
-        // string->float->string, string->double->string or string->long
-        // double->string; to be safe, we read this value from
-        // std::numeric_limits<number_float_t>::digits10
-        const auto old_precision = o.precision(std::numeric_limits<double>::digits10);
-
-        // do the actual serialization
-        j.dump(o, pretty_print, static_cast<unsigned int>(indentation));
-
-        // reset locale and precision
-        o.imbue(old_locale);
-        o.precision(old_precision);
-        return o;
-    }
-
-    /*!
-    @brief serialize to stream
-    @copydoc operator<<(std::ostream&, const basic_json&)
-    */
-    friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
-    {
-        return o << j;
-    }
-
-    /// @}
-
-
-    /////////////////////
-    // deserialization //
-    /////////////////////
-
-    /// @name deserialization
-    /// @{
-
-    /*!
-    @brief deserialize from string
-
-    @param[in] s  string to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-
-    @return result of the deserialization
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below demonstrates the `parse()` function with
-    and without callback function.,parse__string__parser_callback_t}
-
-    @sa @ref parse(std::istream&, const parser_callback_t) for a version that
-    reads from an input stream
-
-    @since version 1.0.0
-    */
-    static basic_json parse(const string_t& s,
-                            const parser_callback_t cb = nullptr)
-    {
-        return parser(s, cb).parse();
-    }
-
-    /*!
-    @brief deserialize from stream
-
-    @param[in,out] i  stream to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-
-    @return result of the deserialization
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below demonstrates the `parse()` function with
-    and without callback function.,parse__istream__parser_callback_t}
-
-    @sa @ref parse(const string_t&, const parser_callback_t) for a version
-    that reads from a string
-
-    @since version 1.0.0
-    */
-    static basic_json parse(std::istream& i,
-                            const parser_callback_t cb = nullptr)
-    {
-        return parser(i, cb).parse();
-    }
-
-    /*!
-    @copydoc parse(std::istream&, const parser_callback_t)
-    */
-    static basic_json parse(std::istream&& i,
-                            const parser_callback_t cb = nullptr)
-    {
-        return parser(i, cb).parse();
-    }
-
-    /*!
-    @brief deserialize from stream
-
-    Deserializes an input stream to a JSON value.
-
-    @param[in,out] i  input stream to read a serialized JSON value from
-    @param[in,out] j  JSON value to write the deserialized input to
-
-    @throw std::invalid_argument in case of parse errors
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below shows how a JSON value is constructed by
-    reading a serialization from a stream.,operator_deserialize}
-
-    @sa parse(std::istream&, const parser_callback_t) for a variant with a
-    parser callback function to filter values while parsing
-
-    @since version 1.0.0
-    */
-    friend std::istream& operator<<(basic_json& j, std::istream& i)
-    {
-        j = parser(i).parse();
-        return i;
-    }
-
-    /*!
-    @brief deserialize from stream
-    @copydoc operator<<(basic_json&, std::istream&)
-    */
-    friend std::istream& operator>>(std::istream& i, basic_json& j)
-    {
-        j = parser(i).parse();
-        return i;
-    }
-
-    /// @}
-
-
-  private:
-    ///////////////////////////
-    // convenience functions //
-    ///////////////////////////
-
-    /*!
-    @brief return the type as string
-
-    Returns the type name as string to be used in error messages - usually to
-    indicate that a function was called on a wrong JSON type.
-
-    @return basically a string representation of a the @ref m_type member
-
-    @complexity Constant.
-
-    @since version 1.0.0
-    */
-    std::string type_name() const
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-                return "null";
-            case value_t::object:
-                return "object";
-            case value_t::array:
-                return "array";
-            case value_t::string:
-                return "string";
-            case value_t::boolean:
-                return "boolean";
-            case value_t::discarded:
-                return "discarded";
-            default:
-                return "number";
-        }
-    }
-
-    /*!
-    @brief calculates the extra space to escape a JSON string
-
-    @param[in] s  the string to escape
-    @return the number of characters required to escape string @a s
-
-    @complexity Linear in the length of string @a s.
-    */
-    static std::size_t extra_space(const string_t& s) noexcept
-    {
-        return std::accumulate(s.begin(), s.end(), size_t{},
-                               [](size_t res, typename string_t::value_type c)
-        {
-            switch (c)
-            {
-                case '"':
-                case '\\':
-                case '\b':
-                case '\f':
-                case '\n':
-                case '\r':
-                case '\t':
-                {
-                    // from c (1 byte) to \x (2 bytes)
-                    return res + 1;
-                }
-
-                default:
-                {
-                    if (c >= 0x00 and c <= 0x1f)
-                    {
-                        // from c (1 byte) to \uxxxx (6 bytes)
-                        return res + 5;
-                    }
-                    else
-                    {
-                        return res;
-                    }
-                }
-            }
-        });
-    }
-
-    /*!
-    @brief escape a string
-
-    Escape a string by replacing certain special characters by a sequence of
-    an escape character (backslash) and another character and other control
-    characters by a sequence of "\u" followed by a four-digit hex
-    representation.
-
-    @param[in] s  the string to escape
-    @return  the escaped string
-
-    @complexity Linear in the length of string @a s.
-    */
-    static string_t escape_string(const string_t& s)
-    {
-        const auto space = extra_space(s);
-        if (space == 0)
-        {
-            return s;
-        }
-
-        // create a result string of necessary size
-        string_t result(s.size() + space, '\\');
-        std::size_t pos = 0;
-
-        for (const auto& c : s)
-        {
-            switch (c)
-            {
-                // quotation mark (0x22)
-                case '"':
-                {
-                    result[pos + 1] = '"';
-                    pos += 2;
-                    break;
-                }
-
-                // reverse solidus (0x5c)
-                case '\\':
-                {
-                    // nothing to change
-                    pos += 2;
-                    break;
-                }
-
-                // backspace (0x08)
-                case '\b':
-                {
-                    result[pos + 1] = 'b';
-                    pos += 2;
-                    break;
-                }
-
-                // formfeed (0x0c)
-                case '\f':
-                {
-                    result[pos + 1] = 'f';
-                    pos += 2;
-                    break;
-                }
-
-                // newline (0x0a)
-                case '\n':
-                {
-                    result[pos + 1] = 'n';
-                    pos += 2;
-                    break;
-                }
-
-                // carriage return (0x0d)
-                case '\r':
-                {
-                    result[pos + 1] = 'r';
-                    pos += 2;
-                    break;
-                }
-
-                // horizontal tab (0x09)
-                case '\t':
-                {
-                    result[pos + 1] = 't';
-                    pos += 2;
-                    break;
-                }
-
-                default:
-                {
-                    if (c >= 0x00 and c <= 0x1f)
-                    {
-                        // convert a number 0..15 to its hex representation
-                        // (0..f)
-                        static const char hexify[16] =
-                        {
-                            '0', '1', '2', '3', '4', '5', '6', '7',
-                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
-                        };
-
-                        // print character c as \uxxxx
-                        for (const char m :
-                    { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f]
-                        })
-                        {
-                            result[++pos] = m;
-                        }
-
-                        ++pos;
-                    }
-                    else
-                    {
-                        // all other characters are added as-is
-                        result[pos++] = c;
-                    }
-                    break;
-                }
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief internal implementation of the serialization function
-
-    This function is called by the public member function dump and organizes
-    the serialization internally. The indentation level is propagated as
-    additional parameter. In case of arrays and objects, the function is
-    called recursively. Note that
-
-    - strings and object keys are escaped using `escape_string()`
-    - integer numbers are converted implicitly via `operator<<`
-    - floating-point numbers are converted to a string using `"%g"` format
-
-    @param[out] o              stream to write to
-    @param[in] pretty_print    whether the output shall be pretty-printed
-    @param[in] indent_step     the indent level
-    @param[in] current_indent  the current indent level (only used internally)
-    */
-    void dump(std::ostream& o,
-              const bool pretty_print,
-              const unsigned int indent_step,
-              const unsigned int current_indent = 0) const
-    {
-        // variable to hold indentation for recursive calls
-        unsigned int new_indent = current_indent;
-
-        switch (m_type)
-        {
-            case value_t::object:
-            {
-                if (m_value.object->empty())
-                {
-                    o << "{}";
-                    return;
-                }
-
-                o << "{";
-
-                // increase indentation
-                if (pretty_print)
-                {
-                    new_indent += indent_step;
-                    o << "\n";
-                }
-
-                for (auto i = m_value.object->cbegin(); i != m_value.object->cend(); ++i)
-                {
-                    if (i != m_value.object->cbegin())
-                    {
-                        o << (pretty_print ? ",\n" : ",");
-                    }
-                    o << string_t(new_indent, ' ') << "\""
-                      << escape_string(i->first) << "\":"
-                      << (pretty_print ? " " : "");
-                    i->second.dump(o, pretty_print, indent_step, new_indent);
-                }
-
-                // decrease indentation
-                if (pretty_print)
-                {
-                    new_indent -= indent_step;
-                    o << "\n";
-                }
-
-                o << string_t(new_indent, ' ') + "}";
-                return;
-            }
-
-            case value_t::array:
-            {
-                if (m_value.array->empty())
-                {
-                    o << "[]";
-                    return;
-                }
-
-                o << "[";
-
-                // increase indentation
-                if (pretty_print)
-                {
-                    new_indent += indent_step;
-                    o << "\n";
-                }
-
-                for (auto i = m_value.array->cbegin(); i != m_value.array->cend(); ++i)
-                {
-                    if (i != m_value.array->cbegin())
-                    {
-                        o << (pretty_print ? ",\n" : ",");
-                    }
-                    o << string_t(new_indent, ' ');
-                    i->dump(o, pretty_print, indent_step, new_indent);
-                }
-
-                // decrease indentation
-                if (pretty_print)
-                {
-                    new_indent -= indent_step;
-                    o << "\n";
-                }
-
-                o << string_t(new_indent, ' ') << "]";
-                return;
-            }
-
-            case value_t::string:
-            {
-                o << string_t("\"") << escape_string(*m_value.string) << "\"";
-                return;
-            }
-
-            case value_t::boolean:
-            {
-                o << (m_value.boolean ? "true" : "false");
-                return;
-            }
-
-            case value_t::number_integer:
-            {
-                o << m_value.number_integer;
-                return;
-            }
-
-            case value_t::number_unsigned:
-            {
-                o << m_value.number_unsigned;
-                return;
-            }
-
-            case value_t::number_float:
-            {
-                if (m_value.number_float == 0)
-                {
-                    // special case for zero to get "0.0"/"-0.0"
-                    o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
-                }
-                else
-                {
-                    o << m_value.number_float;
-                }
-                return;
-            }
-
-            case value_t::discarded:
-            {
-                o << "<discarded>";
-                return;
-            }
-
-            case value_t::null:
-            {
-                o << "null";
-                return;
-            }
-        }
-    }
-
-  private:
-    //////////////////////
-    // member variables //
-    //////////////////////
-
-    /// the type of the current element
-    value_t m_type = value_t::null;
-
-    /// the value of the current element
-    json_value m_value = {};
-
-
-  private:
-    ///////////////
-    // iterators //
-    ///////////////
-
-    /*!
-    @brief an iterator for primitive JSON types
-
-    This class models an iterator for primitive JSON types (boolean, number,
-    string). It's only purpose is to allow the iterator/const_iterator classes
-    to "iterate" over primitive values. Internally, the iterator is modeled by
-    a `difference_type` variable. Value begin_value (`0`) models the begin,
-    end_value (`1`) models past the end.
-    */
-    class primitive_iterator_t
-    {
-      public:
-        /// set iterator to a defined beginning
-        void set_begin() noexcept
-        {
-            m_it = begin_value;
-        }
-
-        /// set iterator to a defined past the end
-        void set_end() noexcept
-        {
-            m_it = end_value;
-        }
-
-        /// return whether the iterator can be dereferenced
-        constexpr bool is_begin() const noexcept
-        {
-            return (m_it == begin_value);
-        }
-
-        /// return whether the iterator is at end
-        constexpr bool is_end() const noexcept
-        {
-            return (m_it == end_value);
-        }
-
-        /// return reference to the value to change and compare
-        operator difference_type& () noexcept
-        {
-            return m_it;
-        }
-
-        /// return value to compare
-        constexpr operator difference_type () const noexcept
-        {
-            return m_it;
-        }
-
-      private:
-        static constexpr difference_type begin_value = 0;
-        static constexpr difference_type end_value = begin_value + 1;
-
-        /// iterator as signed integer type
-        difference_type m_it = std::numeric_limits<std::ptrdiff_t>::denorm_min();
-    };
-
-    /*!
-    @brief an iterator value
-
-    @note This structure could easily be a union, but MSVC currently does not
-    allow unions members with complex constructors, see
-    https://github.com/nlohmann/json/pull/105.
-    */
-    struct internal_iterator
-    {
-        /// iterator for JSON objects
-        typename object_t::iterator object_iterator;
-        /// iterator for JSON arrays
-        typename array_t::iterator array_iterator;
-        /// generic iterator for all other types
-        primitive_iterator_t primitive_iterator;
-
-        /// create an uninitialized internal_iterator
-        internal_iterator() noexcept
-            : object_iterator(), array_iterator(), primitive_iterator()
-        {}
-    };
-
-    /// proxy class for the iterator_wrapper functions
-    template<typename IteratorType>
-    class iteration_proxy
-    {
-      private:
-        /// helper class for iteration
-        class iteration_proxy_internal
-        {
-          private:
-            /// the iterator
-            IteratorType anchor;
-            /// an index for arrays (used to create key names)
-            size_t array_index = 0;
-
-          public:
-            explicit iteration_proxy_internal(IteratorType it) noexcept
-                : anchor(it)
-            {}
-
-            /// dereference operator (needed for range-based for)
-            iteration_proxy_internal& operator*()
-            {
-                return *this;
-            }
-
-            /// increment operator (needed for range-based for)
-            iteration_proxy_internal& operator++()
-            {
-                ++anchor;
-                ++array_index;
-
-                return *this;
-            }
-
-            /// inequality operator (needed for range-based for)
-            bool operator!= (const iteration_proxy_internal& o) const
-            {
-                return anchor != o.anchor;
-            }
-
-            /// return key of the iterator
-            typename basic_json::string_t key() const
-            {
-                assert(anchor.m_object != nullptr);
-
-                switch (anchor.m_object->type())
-                {
-                    // use integer array index as key
-                    case value_t::array:
-                    {
-                        return std::to_string(array_index);
-                    }
-
-                    // use key from the object
-                    case value_t::object:
-                    {
-                        return anchor.key();
-                    }
-
-                    // use an empty key for all primitive types
-                    default:
-                    {
-                        return "";
-                    }
-                }
-            }
-
-            /// return value of the iterator
-            typename IteratorType::reference value() const
-            {
-                return anchor.value();
-            }
-        };
-
-        /// the container to iterate
-        typename IteratorType::reference container;
-
-      public:
-        /// construct iteration proxy from a container
-        explicit iteration_proxy(typename IteratorType::reference cont)
-            : container(cont)
-        {}
-
-        /// return iterator begin (needed for range-based for)
-        iteration_proxy_internal begin() noexcept
-        {
-            return iteration_proxy_internal(container.begin());
-        }
-
-        /// return iterator end (needed for range-based for)
-        iteration_proxy_internal end() noexcept
-        {
-            return iteration_proxy_internal(container.end());
-        }
-    };
-
-  public:
-    /*!
-    @brief a const random access iterator for the @ref basic_json class
-
-    This class implements a const iterator for the @ref basic_json class. From
-    this class, the @ref iterator class is derived.
-
-    @note An iterator is called *initialized* when a pointer to a JSON value
-          has been set (e.g., by a constructor or a copy assignment). If the
-          iterator is default-constructed, it is *uninitialized* and most
-          methods are undefined. The library uses assertions to detect calls
-          on uninitialized iterators.
-
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
-
-    @since version 1.0.0
-    */
-    class const_iterator : public std::iterator<std::random_access_iterator_tag, const basic_json>
-    {
-        /// allow basic_json to access private members
-        friend class basic_json;
-
-      public:
-        /// the type of the values when the iterator is dereferenced
-        using value_type = typename basic_json::value_type;
-        /// a type to represent differences between iterators
-        using difference_type = typename basic_json::difference_type;
-        /// defines a pointer to the type iterated over (value_type)
-        using pointer = typename basic_json::const_pointer;
-        /// defines a reference to the type iterated over (value_type)
-        using reference = typename basic_json::const_reference;
-        /// the category of the iterator
-        using iterator_category = std::bidirectional_iterator_tag;
-
-        /// default constructor
-        const_iterator() = default;
-
-        /*!
-        @brief constructor for a given JSON instance
-        @param[in] object  pointer to a JSON object for this iterator
-        @pre object != nullptr
-        @post The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        explicit const_iterator(pointer object) noexcept
-            : m_object(object)
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = typename object_t::iterator();
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = typename array_t::iterator();
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator = primitive_iterator_t();
-                    break;
-                }
-            }
-        }
-
-        /*!
-        @brief copy constructor given a non-const iterator
-        @param[in] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
-        */
-        explicit const_iterator(const iterator& other) noexcept
-            : m_object(other.m_object)
-        {
-            if (m_object != nullptr)
-            {
-                switch (m_object->m_type)
-                {
-                    case basic_json::value_t::object:
-                    {
-                        m_it.object_iterator = other.m_it.object_iterator;
-                        break;
-                    }
-
-                    case basic_json::value_t::array:
-                    {
-                        m_it.array_iterator = other.m_it.array_iterator;
-                        break;
-                    }
-
-                    default:
-                    {
-                        m_it.primitive_iterator = other.m_it.primitive_iterator;
-                        break;
-                    }
-                }
-            }
-        }
-
-        /*!
-        @brief copy constructor
-        @param[in] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
-        */
-        const_iterator(const const_iterator& other) noexcept
-            : m_object(other.m_object), m_it(other.m_it)
-        {}
-
-        /*!
-        @brief copy assignment
-        @param[in,out] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
-        */
-        const_iterator& operator=(const_iterator other) noexcept(
-            std::is_nothrow_move_constructible<pointer>::value and
-            std::is_nothrow_move_assignable<pointer>::value and
-            std::is_nothrow_move_constructible<internal_iterator>::value and
-            std::is_nothrow_move_assignable<internal_iterator>::value
-        )
-        {
-            std::swap(m_object, other.m_object);
-            std::swap(m_it, other.m_it);
-            return *this;
-        }
-
-      private:
-        /*!
-        @brief set the iterator to the first value
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        void set_begin() noexcept
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = m_object->m_value.object->begin();
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = m_object->m_value.array->begin();
-                    break;
-                }
-
-                case basic_json::value_t::null:
-                {
-                    // set to end so begin()==end() is true: null is empty
-                    m_it.primitive_iterator.set_end();
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator.set_begin();
-                    break;
-                }
-            }
-        }
-
-        /*!
-        @brief set the iterator past the last value
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        void set_end() noexcept
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = m_object->m_value.object->end();
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = m_object->m_value.array->end();
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator.set_end();
-                    break;
-                }
-            }
-        }
-
-      public:
-        /*!
-        @brief return a reference to the value pointed to by the iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference operator*() const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    assert(m_it.object_iterator != m_object->m_value.object->end());
-                    return m_it.object_iterator->second;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    assert(m_it.array_iterator != m_object->m_value.array->end());
-                    return *m_it.array_iterator;
-                }
-
-                case basic_json::value_t::null:
-                {
-                    throw std::out_of_range("cannot get value");
-                }
-
-                default:
-                {
-                    if (m_it.primitive_iterator.is_begin())
-                    {
-                        return *m_object;
-                    }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
-                }
-            }
-        }
-
-        /*!
-        @brief dereference the iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        pointer operator->() const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    assert(m_it.object_iterator != m_object->m_value.object->end());
-                    return &(m_it.object_iterator->second);
-                }
-
-                case basic_json::value_t::array:
-                {
-                    assert(m_it.array_iterator != m_object->m_value.array->end());
-                    return &*m_it.array_iterator;
-                }
-
-                default:
-                {
-                    if (m_it.primitive_iterator.is_begin())
-                    {
-                        return m_object;
-                    }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
-                }
-            }
-        }
-
-        /*!
-        @brief post-increment (it++)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator operator++(int)
-        {
-            auto result = *this;
-            ++(*this);
-            return result;
-        }
-
-        /*!
-        @brief pre-increment (++it)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator& operator++()
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    std::advance(m_it.object_iterator, 1);
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, 1);
-                    break;
-                }
-
-                default:
-                {
-                    ++m_it.primitive_iterator;
-                    break;
-                }
-            }
-
-            return *this;
-        }
-
-        /*!
-        @brief post-decrement (it--)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator operator--(int)
-        {
-            auto result = *this;
-            --(*this);
-            return result;
-        }
-
-        /*!
-        @brief pre-decrement (--it)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator& operator--()
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    std::advance(m_it.object_iterator, -1);
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, -1);
-                    break;
-                }
-
-                default:
-                {
-                    --m_it.primitive_iterator;
-                    break;
-                }
-            }
-
-            return *this;
-        }
-
-        /*!
-        @brief  comparison: equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator==(const const_iterator& other) const
-        {
-            // if objects are not the same, the comparison is undefined
-            if (m_object != other.m_object)
-            {
-                throw std::domain_error("cannot compare iterators of different containers");
-            }
-
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    return (m_it.object_iterator == other.m_it.object_iterator);
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return (m_it.array_iterator == other.m_it.array_iterator);
-                }
-
-                default:
-                {
-                    return (m_it.primitive_iterator == other.m_it.primitive_iterator);
-                }
-            }
-        }
-
-        /*!
-        @brief  comparison: not equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator!=(const const_iterator& other) const
-        {
-            return not operator==(other);
-        }
-
-        /*!
-        @brief  comparison: smaller
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator<(const const_iterator& other) const
-        {
-            // if objects are not the same, the comparison is undefined
-            if (m_object != other.m_object)
-            {
-                throw std::domain_error("cannot compare iterators of different containers");
-            }
-
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    throw std::domain_error("cannot compare order of object iterators");
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return (m_it.array_iterator < other.m_it.array_iterator);
-                }
-
-                default:
-                {
-                    return (m_it.primitive_iterator < other.m_it.primitive_iterator);
-                }
-            }
-        }
-
-        /*!
-        @brief  comparison: less than or equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator<=(const const_iterator& other) const
-        {
-            return not other.operator < (*this);
-        }
-
-        /*!
-        @brief  comparison: greater than
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator>(const const_iterator& other) const
-        {
-            return not operator<=(other);
-        }
-
-        /*!
-        @brief  comparison: greater than or equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator>=(const const_iterator& other) const
-        {
-            return not operator<(other);
-        }
-
-        /*!
-        @brief  add to iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator& operator+=(difference_type i)
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    throw std::domain_error("cannot use offsets with object iterators");
-                }
-
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, i);
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator += i;
-                    break;
-                }
-            }
-
-            return *this;
-        }
-
-        /*!
-        @brief  subtract from iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator& operator-=(difference_type i)
-        {
-            return operator+=(-i);
-        }
-
-        /*!
-        @brief  add to iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator operator+(difference_type i)
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
-
-        /*!
-        @brief  subtract from iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        const_iterator operator-(difference_type i)
-        {
-            auto result = *this;
-            result -= i;
-            return result;
-        }
-
-        /*!
-        @brief  return difference
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        difference_type operator-(const const_iterator& other) const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    throw std::domain_error("cannot use offsets with object iterators");
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return m_it.array_iterator - other.m_it.array_iterator;
-                }
-
-                default:
-                {
-                    return m_it.primitive_iterator - other.m_it.primitive_iterator;
-                }
-            }
-        }
-
-        /*!
-        @brief  access to successor
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference operator[](difference_type n) const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    throw std::domain_error("cannot use operator[] for object iterators");
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return *std::next(m_it.array_iterator, n);
-                }
-
-                case basic_json::value_t::null:
-                {
-                    throw std::out_of_range("cannot get value");
-                }
-
-                default:
-                {
-                    if (m_it.primitive_iterator == -n)
-                    {
-                        return *m_object;
-                    }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
-                }
-            }
-        }
-
-        /*!
-        @brief  return the key of an object iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        typename object_t::key_type key() const
-        {
-            assert(m_object != nullptr);
-
-            if (m_object->is_object())
-            {
-                return m_it.object_iterator->first;
-            }
-            else
-            {
-                throw std::domain_error("cannot use key() for non-object iterators");
-            }
-        }
-
-        /*!
-        @brief  return the value of an iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference value() const
-        {
-            return operator*();
-        }
-
-      private:
-        /// associated JSON instance
-        pointer m_object = nullptr;
-        /// the actual iterator of the associated instance
-        internal_iterator m_it = internal_iterator();
-    };
-
-    /*!
-    @brief a mutable random access iterator for the @ref basic_json class
-
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
-    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
-      It is possible to write to the pointed-to element.
-
-    @since version 1.0.0
-    */
-    class iterator : public const_iterator
-    {
-      public:
-        using base_iterator = const_iterator;
-        using pointer = typename basic_json::pointer;
-        using reference = typename basic_json::reference;
-
-        /// default constructor
-        iterator() = default;
-
-        /// constructor for a given JSON instance
-        explicit iterator(pointer object) noexcept
-            : base_iterator(object)
-        {}
-
-        /// copy constructor
-        iterator(const iterator& other) noexcept
-            : base_iterator(other)
-        {}
-
-        /// copy assignment
-        iterator& operator=(iterator other) noexcept(
-            std::is_nothrow_move_constructible<pointer>::value and
-            std::is_nothrow_move_assignable<pointer>::value and
-            std::is_nothrow_move_constructible<internal_iterator>::value and
-            std::is_nothrow_move_assignable<internal_iterator>::value
-        )
-        {
-            base_iterator::operator=(other);
-            return *this;
-        }
-
-        /// return a reference to the value pointed to by the iterator
-        reference operator*() const
-        {
-            return const_cast<reference>(base_iterator::operator*());
-        }
-
-        /// dereference the iterator
-        pointer operator->() const
-        {
-            return const_cast<pointer>(base_iterator::operator->());
-        }
-
-        /// post-increment (it++)
-        iterator operator++(int)
-        {
-            iterator result = *this;
-            base_iterator::operator++();
-            return result;
-        }
-
-        /// pre-increment (++it)
-        iterator& operator++()
-        {
-            base_iterator::operator++();
-            return *this;
-        }
-
-        /// post-decrement (it--)
-        iterator operator--(int)
-        {
-            iterator result = *this;
-            base_iterator::operator--();
-            return result;
-        }
-
-        /// pre-decrement (--it)
-        iterator& operator--()
-        {
-            base_iterator::operator--();
-            return *this;
-        }
-
-        /// add to iterator
-        iterator& operator+=(difference_type i)
-        {
-            base_iterator::operator+=(i);
-            return *this;
-        }
-
-        /// subtract from iterator
-        iterator& operator-=(difference_type i)
-        {
-            base_iterator::operator-=(i);
-            return *this;
-        }
-
-        /// add to iterator
-        iterator operator+(difference_type i)
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
-
-        /// subtract from iterator
-        iterator operator-(difference_type i)
-        {
-            auto result = *this;
-            result -= i;
-            return result;
-        }
-
-        /// return difference
-        difference_type operator-(const iterator& other) const
-        {
-            return base_iterator::operator-(other);
-        }
-
-        /// access to successor
-        reference operator[](difference_type n) const
-        {
-            return const_cast<reference>(base_iterator::operator[](n));
-        }
-
-        /// return the value of an iterator
-        reference value() const
-        {
-            return const_cast<reference>(base_iterator::value());
-        }
-    };
-
-    /*!
-    @brief a template for a reverse iterator class
-
-    @tparam Base the base iterator type to reverse. Valid types are @ref
-    iterator (to create @ref reverse_iterator) and @ref const_iterator (to
-    create @ref const_reverse_iterator).
-
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
-    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
-      It is possible to write to the pointed-to element (only if @a Base is
-      @ref iterator).
-
-    @since version 1.0.0
-    */
-    template<typename Base>
-    class json_reverse_iterator : public std::reverse_iterator<Base>
-    {
-      public:
-        /// shortcut to the reverse iterator adaptor
-        using base_iterator = std::reverse_iterator<Base>;
-        /// the reference type for the pointed-to element
-        using reference = typename Base::reference;
-
-        /// create reverse iterator from iterator
-        json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept
-            : base_iterator(it)
-        {}
-
-        /// create reverse iterator from base class
-        json_reverse_iterator(const base_iterator& it) noexcept
-            : base_iterator(it)
-        {}
-
-        /// post-increment (it++)
-        json_reverse_iterator operator++(int)
-        {
-            return base_iterator::operator++(1);
-        }
-
-        /// pre-increment (++it)
-        json_reverse_iterator& operator++()
-        {
-            base_iterator::operator++();
-            return *this;
-        }
-
-        /// post-decrement (it--)
-        json_reverse_iterator operator--(int)
-        {
-            return base_iterator::operator--(1);
-        }
-
-        /// pre-decrement (--it)
-        json_reverse_iterator& operator--()
-        {
-            base_iterator::operator--();
-            return *this;
-        }
-
-        /// add to iterator
-        json_reverse_iterator& operator+=(difference_type i)
-        {
-            base_iterator::operator+=(i);
-            return *this;
-        }
-
-        /// add to iterator
-        json_reverse_iterator operator+(difference_type i) const
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
-
-        /// subtract from iterator
-        json_reverse_iterator operator-(difference_type i) const
-        {
-            auto result = *this;
-            result -= i;
-            return result;
-        }
-
-        /// return difference
-        difference_type operator-(const json_reverse_iterator& other) const
-        {
-            return this->base() - other.base();
-        }
-
-        /// access to successor
-        reference operator[](difference_type n) const
-        {
-            return *(this->operator+(n));
-        }
-
-        /// return the key of an object iterator
-        typename object_t::key_type key() const
-        {
-            auto it = --this->base();
-            return it.key();
-        }
-
-        /// return the value of an iterator
-        reference value() const
-        {
-            auto it = --this->base();
-            return it.operator * ();
-        }
-    };
-
-
-  private:
-    //////////////////////
-    // lexer and parser //
-    //////////////////////
-
-    /*!
-    @brief lexical analysis
-
-    This class organizes the lexical analysis during JSON deserialization. The
-    core of it is a scanner generated by [re2c](http://re2c.org) that
-    processes a buffer and recognizes tokens according to RFC 7159.
-    */
-    class lexer
-    {
-      public:
-        /// token types for the parser
-        enum class token_type
-        {
-            uninitialized,   ///< indicating the scanner is uninitialized
-            literal_true,    ///< the `true` literal
-            literal_false,   ///< the `false` literal
-            literal_null,    ///< the `null` literal
-            value_string,    ///< a string -- use get_string() for actual value
-            value_number,    ///< a number -- use get_number() for actual value
-            begin_array,     ///< the character for array begin `[`
-            begin_object,    ///< the character for object begin `{`
-            end_array,       ///< the character for array end `]`
-            end_object,      ///< the character for object end `}`
-            name_separator,  ///< the name separator `:`
-            value_separator, ///< the value separator `,`
-            parse_error,     ///< indicating a parse error
-            end_of_input     ///< indicating the end of the input buffer
-        };
-
-        /// the char type to use in the lexer
-        using lexer_char_t = unsigned char;
-
-        /// constructor with a given buffer
-        explicit lexer(const string_t& s) noexcept
-            : m_stream(nullptr), m_buffer(s)
-        {
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
-            assert(m_content != nullptr);
-            m_start = m_cursor = m_content;
-            m_limit = m_content + s.size();
-        }
-
-        /// constructor with a given stream
-        explicit lexer(std::istream* s) noexcept
-            : m_stream(s), m_buffer()
-        {
-            assert(m_stream != nullptr);
-            std::getline(*m_stream, m_buffer);
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
-            assert(m_content != nullptr);
-            m_start = m_cursor = m_content;
-            m_limit = m_content + m_buffer.size();
-        }
-
-        /// default constructor
-        lexer() = default;
-
-        // switch off unwanted functions
-        lexer(const lexer&) = delete;
-        lexer operator=(const lexer&) = delete;
-
-        /*!
-        @brief create a string from one or two Unicode code points
-
-        There are two cases: (1) @a codepoint1 is in the Basic Multilingual
-        Plane (U+0000 through U+FFFF) and @a codepoint2 is 0, or (2)
-        @a codepoint1 and @a codepoint2 are a UTF-16 surrogate pair to
-        represent a code point above U+FFFF.
-
-        @param[in] codepoint1  the code point (can be high surrogate)
-        @param[in] codepoint2  the code point (can be low surrogate or 0)
-
-        @return string representation of the code point; the length of the
-        result string is between 1 and 4 characters.
-
-        @throw std::out_of_range if code point is > 0x10ffff; example: `"code
-        points above 0x10FFFF are invalid"`
-        @throw std::invalid_argument if the low surrogate is invalid; example:
-        `""missing or wrong low surrogate""`
-
-        @complexity Constant.
-
-        @see <http://en.wikipedia.org/wiki/UTF-8#Sample_code>
-        */
-        static string_t to_unicode(const std::size_t codepoint1,
-                                   const std::size_t codepoint2 = 0)
-        {
-            // calculate the code point from the given code points
-            std::size_t codepoint = codepoint1;
-
-            // check if codepoint1 is a high surrogate
-            if (codepoint1 >= 0xD800 and codepoint1 <= 0xDBFF)
-            {
-                // check if codepoint2 is a low surrogate
-                if (codepoint2 >= 0xDC00 and codepoint2 <= 0xDFFF)
-                {
-                    codepoint =
-                        // high surrogate occupies the most significant 22 bits
-                        (codepoint1 << 10)
-                        // low surrogate occupies the least significant 15 bits
-                        + codepoint2
-                        // there is still the 0xD800, 0xDC00 and 0x10000 noise
-                        // in the result so we have to subtract with:
-                        // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
-                        - 0x35FDC00;
-                }
-                else
-                {
-                    throw std::invalid_argument("missing or wrong low surrogate");
-                }
-            }
-
-            string_t result;
-
-            if (codepoint < 0x80)
-            {
-                // 1-byte characters: 0xxxxxxx (ASCII)
-                result.append(1, static_cast<typename string_t::value_type>(codepoint));
-            }
-            else if (codepoint <= 0x7ff)
-            {
-                // 2-byte characters: 110xxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xC0 | ((codepoint >> 6) & 0x1F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else if (codepoint <= 0xffff)
-            {
-                // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xE0 | ((codepoint >> 12) & 0x0F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else if (codepoint <= 0x10ffff)
-            {
-                // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xF0 | ((codepoint >> 18) & 0x07)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 12) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else
-            {
-                throw std::out_of_range("code points above 0x10FFFF are invalid");
-            }
-
-            return result;
-        }
-
-        /// return name of values of type token_type (only used for errors)
-        static std::string token_type_name(const token_type t)
-        {
-            switch (t)
-            {
-                case token_type::uninitialized:
-                    return "<uninitialized>";
-                case token_type::literal_true:
-                    return "true literal";
-                case token_type::literal_false:
-                    return "false literal";
-                case token_type::literal_null:
-                    return "null literal";
-                case token_type::value_string:
-                    return "string literal";
-                case token_type::value_number:
-                    return "number literal";
-                case token_type::begin_array:
-                    return "'['";
-                case token_type::begin_object:
-                    return "'{'";
-                case token_type::end_array:
-                    return "']'";
-                case token_type::end_object:
-                    return "'}'";
-                case token_type::name_separator:
-                    return "':'";
-                case token_type::value_separator:
-                    return "','";
-                case token_type::parse_error:
-                    return "<parse error>";
-                case token_type::end_of_input:
-                    return "end of input";
-                default:
-                {
-                    // catch non-enum values
-                    return "unknown token"; // LCOV_EXCL_LINE
-                }
-            }
-        }
-
-        /*!
-        This function implements a scanner for JSON. It is specified using
-        regular expressions that try to follow RFC 7159 as close as possible.
-        These regular expressions are then translated into a minimized
-        deterministic finite automaton (DFA) by the tool
-        [re2c](http://re2c.org). As a result, the translated code for this
-        function consists of a large block of code with `goto` jumps.
-
-        @return the class of the next token read from the buffer
-
-        @complexity Linear in the length of the input.\n
-
-        Proposition: The loop below will always terminate for finite input.\n
-
-        Proof (by contradiction): Assume a finite input. To loop forever, the
-        loop must never hit code with a `break` statement. The only code
-        snippets without a `break` statement are the continue statements for
-        whitespace and byte-order-marks. To loop forever, the input must be an
-        infinite sequence of whitespace or byte-order-marks. This contradicts
-        the assumption of finite input, q.e.d.
-        */
-        token_type scan() noexcept
-        {
-            while (true)
-            {
-                // pointer for backtracking information
-                m_marker = nullptr;
-
-                // remember the begin of the token
-                m_start = m_cursor;
-                assert(m_start != nullptr);
-
-
-                {
-                    lexer_char_t yych;
-                    unsigned int yyaccept = 0;
-                    static const unsigned char yybm[] =
-                    {
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,  32,  32,   0,   0,  32,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        160, 128,   0, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        192, 192, 192, 192, 192, 192, 192, 192,
-                        192, 192, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128,   0, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                    };
-                    if ((m_limit - m_cursor) < 5)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 32)
-                    {
-                        goto basic_json_parser_6;
-                    }
-                    if (yych <= '\\')
-                    {
-                        if (yych <= '-')
-                        {
-                            if (yych <= '"')
-                            {
-                                if (yych <= 0x00)
-                                {
-                                    goto basic_json_parser_2;
-                                }
-                                if (yych <= '!')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_9;
-                            }
-                            else
-                            {
-                                if (yych <= '+')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                if (yych <= ',')
-                                {
-                                    goto basic_json_parser_10;
-                                }
-                                goto basic_json_parser_12;
-                            }
-                        }
-                        else
-                        {
-                            if (yych <= '9')
-                            {
-                                if (yych <= '/')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                if (yych <= '0')
-                                {
-                                    goto basic_json_parser_13;
-                                }
-                                goto basic_json_parser_15;
-                            }
-                            else
-                            {
-                                if (yych <= ':')
-                                {
-                                    goto basic_json_parser_17;
-                                }
-                                if (yych == '[')
-                                {
-                                    goto basic_json_parser_19;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 't')
-                        {
-                            if (yych <= 'f')
-                            {
-                                if (yych <= ']')
-                                {
-                                    goto basic_json_parser_21;
-                                }
-                                if (yych <= 'e')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_23;
-                            }
-                            else
-                            {
-                                if (yych == 'n')
-                                {
-                                    goto basic_json_parser_24;
-                                }
-                                if (yych <= 's')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_25;
-                            }
-                        }
-                        else
-                        {
-                            if (yych <= '|')
-                            {
-                                if (yych == '{')
-                                {
-                                    goto basic_json_parser_26;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                            else
-                            {
-                                if (yych <= '}')
-                                {
-                                    goto basic_json_parser_28;
-                                }
-                                if (yych == 0xEF)
-                                {
-                                    goto basic_json_parser_30;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                        }
-                    }
-basic_json_parser_2:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_of_input;
-                        break;
-                    }
-basic_json_parser_4:
-                    ++m_cursor;
-basic_json_parser_5:
-                    {
-                        last_token_type = token_type::parse_error;
-                        break;
-                    }
-basic_json_parser_6:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 32)
-                    {
-                        goto basic_json_parser_6;
-                    }
-                    {
-                        continue;
-                    }
-basic_json_parser_9:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych <= 0x1F)
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_10:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::value_separator;
-                        break;
-                    }
-basic_json_parser_12:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    if (yych <= '0')
-                    {
-                        goto basic_json_parser_13;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_15;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_13:
-                    yyaccept = 1;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych <= 'D')
-                    {
-                        if (yych == '.')
-                        {
-                            goto basic_json_parser_37;
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        if (yych == 'e')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                    }
-basic_json_parser_14:
-                    {
-                        last_token_type = token_type::value_number;
-                        break;
-                    }
-basic_json_parser_15:
-                    yyaccept = 1;
-                    m_marker = ++m_cursor;
-                    if ((m_limit - m_cursor) < 3)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 64)
-                    {
-                        goto basic_json_parser_15;
-                    }
-                    if (yych <= 'D')
-                    {
-                        if (yych == '.')
-                        {
-                            goto basic_json_parser_37;
-                        }
-                        goto basic_json_parser_14;
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        if (yych == 'e')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        goto basic_json_parser_14;
-                    }
-basic_json_parser_17:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::name_separator;
-                        break;
-                    }
-basic_json_parser_19:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::begin_array;
-                        break;
-                    }
-basic_json_parser_21:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_array;
-                        break;
-                    }
-basic_json_parser_23:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'a')
-                    {
-                        goto basic_json_parser_39;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_24:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'u')
-                    {
-                        goto basic_json_parser_40;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_25:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'r')
-                    {
-                        goto basic_json_parser_41;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_26:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::begin_object;
-                        break;
-                    }
-basic_json_parser_28:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_object;
-                        break;
-                    }
-basic_json_parser_30:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 0xBB)
-                    {
-                        goto basic_json_parser_42;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_31:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-basic_json_parser_32:
-                    if (yybm[0 + yych] & 128)
-                    {
-                        goto basic_json_parser_31;
-                    }
-                    if (yych <= 0x1F)
-                    {
-                        goto basic_json_parser_33;
-                    }
-                    if (yych <= '"')
-                    {
-                        goto basic_json_parser_34;
-                    }
-                    goto basic_json_parser_36;
-basic_json_parser_33:
-                    m_cursor = m_marker;
-                    if (yyaccept == 0)
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    else
-                    {
-                        goto basic_json_parser_14;
-                    }
-basic_json_parser_34:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::value_string;
-                        break;
-                    }
-basic_json_parser_36:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 'e')
-                    {
-                        if (yych <= '/')
-                        {
-                            if (yych == '"')
-                            {
-                                goto basic_json_parser_31;
-                            }
-                            if (yych <= '.')
-                            {
-                                goto basic_json_parser_33;
-                            }
-                            goto basic_json_parser_31;
-                        }
-                        else
-                        {
-                            if (yych <= '\\')
-                            {
-                                if (yych <= '[')
-                                {
-                                    goto basic_json_parser_33;
-                                }
-                                goto basic_json_parser_31;
-                            }
-                            else
-                            {
-                                if (yych == 'b')
-                                {
-                                    goto basic_json_parser_31;
-                                }
-                                goto basic_json_parser_33;
-                            }
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'q')
-                        {
-                            if (yych <= 'f')
-                            {
-                                goto basic_json_parser_31;
-                            }
-                            if (yych == 'n')
-                            {
-                                goto basic_json_parser_31;
-                            }
-                            goto basic_json_parser_33;
-                        }
-                        else
-                        {
-                            if (yych <= 's')
-                            {
-                                if (yych <= 'r')
-                                {
-                                    goto basic_json_parser_31;
-                                }
-                                goto basic_json_parser_33;
-                            }
-                            else
-                            {
-                                if (yych <= 't')
-                                {
-                                    goto basic_json_parser_31;
-                                }
-                                if (yych <= 'u')
-                                {
-                                    goto basic_json_parser_43;
-                                }
-                                goto basic_json_parser_33;
-                            }
-                        }
-                    }
-basic_json_parser_37:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_33;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_44;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_38:
-                    yych = *++m_cursor;
-                    if (yych <= ',')
-                    {
-                        if (yych == '+')
-                        {
-                            goto basic_json_parser_46;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= '-')
-                        {
-                            goto basic_json_parser_46;
-                        }
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_47;
-                        }
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_39:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_49;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_40:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_50;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_41:
-                    yych = *++m_cursor;
-                    if (yych == 'u')
-                    {
-                        goto basic_json_parser_51;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_42:
-                    yych = *++m_cursor;
-                    if (yych == 0xBF)
-                    {
-                        goto basic_json_parser_52;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_43:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_54;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_54;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_54;
-                        }
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_44:
-                    yyaccept = 1;
-                    m_marker = ++m_cursor;
-                    if ((m_limit - m_cursor) < 3)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 'D')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_14;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_44;
-                        }
-                        goto basic_json_parser_14;
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        if (yych == 'e')
-                        {
-                            goto basic_json_parser_38;
-                        }
-                        goto basic_json_parser_14;
-                    }
-basic_json_parser_46:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_33;
-                    }
-                    if (yych >= ':')
-                    {
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_47:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_14;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_47;
-                    }
-                    goto basic_json_parser_14;
-basic_json_parser_49:
-                    yych = *++m_cursor;
-                    if (yych == 's')
-                    {
-                        goto basic_json_parser_55;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_50:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_56;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_51:
-                    yych = *++m_cursor;
-                    if (yych == 'e')
-                    {
-                        goto basic_json_parser_58;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_52:
-                    ++m_cursor;
-                    {
-                        continue;
-                    }
-basic_json_parser_54:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_60;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_60;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_60;
-                        }
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_55:
-                    yych = *++m_cursor;
-                    if (yych == 'e')
-                    {
-                        goto basic_json_parser_61;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_56:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_null;
-                        break;
-                    }
-basic_json_parser_58:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_true;
-                        break;
-                    }
-basic_json_parser_60:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_63;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_63;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_63;
-                        }
-                        goto basic_json_parser_33;
-                    }
-basic_json_parser_61:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_false;
-                        break;
-                    }
-basic_json_parser_63:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        yyfill();    // LCOV_EXCL_LINE;
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_31;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_31;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_33;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_31;
-                        }
-                        goto basic_json_parser_33;
-                    }
-                }
-
-            }
-
-            return last_token_type;
-        }
-
-        /// append data from the stream to the internal buffer
-        void yyfill() noexcept
-        {
-            if (m_stream == nullptr or not * m_stream)
-            {
-                return;
-            }
-
-            const auto offset_start = m_start - m_content;
-            const auto offset_marker = m_marker - m_start;
-            const auto offset_cursor = m_cursor - m_start;
-
-            m_buffer.erase(0, static_cast<size_t>(offset_start));
-            std::string line;
-            assert(m_stream != nullptr);
-            std::getline(*m_stream, line);
-            m_buffer += "\n" + line; // add line with newline symbol
-
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
-            assert(m_content != nullptr);
-            m_start  = m_content;
-            m_marker = m_start + offset_marker;
-            m_cursor = m_start + offset_cursor;
-            m_limit  = m_start + m_buffer.size() - 1;
-        }
-
-        /// return string representation of last read token
-        string_t get_token_string() const
-        {
-            assert(m_start != nullptr);
-            return string_t(reinterpret_cast<typename string_t::const_pointer>(m_start),
-                            static_cast<size_t>(m_cursor - m_start));
-        }
-
-        /*!
-        @brief return string value for string tokens
-
-        The function iterates the characters between the opening and closing
-        quotes of the string value. The complete string is the range
-        [m_start,m_cursor). Consequently, we iterate from m_start+1 to
-        m_cursor-1.
-
-        We differentiate two cases:
-
-        1. Escaped characters. In this case, a new character is constructed
-           according to the nature of the escape. Some escapes create new
-           characters (e.g., `"\\n"` is replaced by `"\n"`), some are copied
-           as is (e.g., `"\\\\"`). Furthermore, Unicode escapes of the shape
-           `"\\uxxxx"` need special care. In this case, to_unicode takes care
-           of the construction of the values.
-        2. Unescaped characters are copied as is.
-
-        @pre `m_cursor - m_start >= 2`, meaning the length of the last token
-        is at least 2 bytes which is trivially true for any string (which
-        consists of at least two quotes).
-
-            " c1 c2 c3 ... "
-            ^                ^
-            m_start          m_cursor
-
-        @complexity Linear in the length of the string.\n
-
-        Lemma: The loop body will always terminate.\n
-
-        Proof (by contradiction): Assume the loop body does not terminate. As
-        the loop body does not contain another loop, one of the called
-        functions must never return. The called functions are `std::strtoul`
-        and to_unicode. Neither function can loop forever, so the loop body
-        will never loop forever which contradicts the assumption that the loop
-        body does not terminate, q.e.d.\n
-
-        Lemma: The loop condition for the for loop is eventually false.\n
-
-        Proof (by contradiction): Assume the loop does not terminate. Due to
-        the above lemma, this can only be due to a tautological loop
-        condition; that is, the loop condition i < m_cursor - 1 must always be
-        true. Let x be the change of i for any loop iteration. Then
-        m_start + 1 + x < m_cursor - 1 must hold to loop indefinitely. This
-        can be rephrased to m_cursor - m_start - 2 > x. With the
-        precondition, we x <= 0, meaning that the loop condition holds
-        indefinitly if i is always decreased. However, observe that the value
-        of i is strictly increasing with each iteration, as it is incremented
-        by 1 in the iteration expression and never decremented inside the loop
-        body. Hence, the loop condition will eventually be false which
-        contradicts the assumption that the loop condition is a tautology,
-        q.e.d.
-
-        @return string value of current token without opening and closing
-        quotes
-        @throw std::out_of_range if to_unicode fails
-        */
-        string_t get_string() const
-        {
-            assert(m_cursor - m_start >= 2);
-
-            string_t result;
-            result.reserve(static_cast<size_t>(m_cursor - m_start - 2));
-
-            // iterate the result between the quotes
-            for (const lexer_char_t* i = m_start + 1; i < m_cursor - 1; ++i)
-            {
-                // process escaped characters
-                if (*i == '\\')
-                {
-                    // read next character
-                    ++i;
-
-                    switch (*i)
-                    {
-                        // the default escapes
-                        case 't':
-                        {
-                            result += "\t";
-                            break;
-                        }
-                        case 'b':
-                        {
-                            result += "\b";
-                            break;
-                        }
-                        case 'f':
-                        {
-                            result += "\f";
-                            break;
-                        }
-                        case 'n':
-                        {
-                            result += "\n";
-                            break;
-                        }
-                        case 'r':
-                        {
-                            result += "\r";
-                            break;
-                        }
-                        case '\\':
-                        {
-                            result += "\\";
-                            break;
-                        }
-                        case '/':
-                        {
-                            result += "/";
-                            break;
-                        }
-                        case '"':
-                        {
-                            result += "\"";
-                            break;
-                        }
-
-                        // unicode
-                        case 'u':
-                        {
-                            // get code xxxx from uxxxx
-                            auto codepoint = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>(i + 1),
-                                                          4).c_str(), nullptr, 16);
-
-                            // check if codepoint is a high surrogate
-                            if (codepoint >= 0xD800 and codepoint <= 0xDBFF)
-                            {
-                                // make sure there is a subsequent unicode
-                                if ((i + 6 >= m_limit) or * (i + 5) != '\\' or * (i + 6) != 'u')
-                                {
-                                    throw std::invalid_argument("missing low surrogate");
-                                }
-
-                                // get code yyyy from uxxxx\uyyyy
-                                auto codepoint2 = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>
-                                                               (i + 7), 4).c_str(), nullptr, 16);
-                                result += to_unicode(codepoint, codepoint2);
-                                // skip the next 10 characters (xxxx\uyyyy)
-                                i += 10;
-                            }
-                            else
-                            {
-                                // add unicode character(s)
-                                result += to_unicode(codepoint);
-                                // skip the next four characters (xxxx)
-                                i += 4;
-                            }
-                            break;
-                        }
-                    }
-                }
-                else
-                {
-                    // all other characters are just copied to the end of the
-                    // string
-                    result.append(1, static_cast<typename string_t::value_type>(*i));
-                }
-            }
-
-            return result;
-        }
-
-        /*!
-        @brief parse floating point number
-
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
-
-        @param[in] type  the @ref number_float_t in use
-
-        @param[in,out] endptr recieves a pointer to the first character after
-        the number
-
-        @return the floating point number
-        */
-        long double str_to_float_t(long double* /* type */, char** endptr) const
-        {
-            return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
-
-        /*!
-        @brief parse floating point number
-
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
-
-        @param[in] type  the @ref number_float_t in use
-
-        @param[in,out] endptr  recieves a pointer to the first character after
-        the number
-
-        @return the floating point number
-        */
-        double str_to_float_t(double* /* type */, char** endptr) const
-        {
-            return std::strtod(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
-
-        /*!
-        @brief parse floating point number
-
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
-
-        @param[in] type  the @ref number_float_t in use
-
-        @param[in,out] endptr  recieves a pointer to the first character after
-        the number
-
-        @return the floating point number
-        */
-        float str_to_float_t(float* /* type */, char** endptr) const
-        {
-            return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
-
-        /*!
-        @brief return number value for number tokens
-
-        This function translates the last token into the most appropriate
-        number type (either integer, unsigned integer or floating point),
-        which is passed back to the caller via the result parameter.
-
-        This function parses the integer component up to the radix point or
-        exponent while collecting information about the 'floating point
-        representation', which it stores in the result parameter. If there is
-        no radix point or exponent, and the number can fit into a @ref
-        number_integer_t or @ref number_unsigned_t then it sets the result
-        parameter accordingly.
-
-        If the number is a floating point number the number is then parsed
-        using @a std:strtod (or @a std:strtof or @a std::strtold).
-
-        @param[out] result  @ref basic_json object to receive the number, or
-        NAN if the conversion read past the current token. The latter case
-        needs to be treated by the caller function.
-        */
-        void get_number(basic_json& result) const
-        {
-            assert(m_start != nullptr);
-
-            const lexer::lexer_char_t* curptr = m_start;
-
-            // accumulate the integer conversion result (unsigned for now)
-            number_unsigned_t value = 0;
-
-            // maximum absolute value of the relevant integer type
-            number_unsigned_t max;
-
-            // temporarily store the type to avoid unecessary bitfield access
-            value_t type;
-
-            // look for sign
-            if (*curptr == '-')
-            {
-                type = value_t::number_integer;
-                max = static_cast<uint64_t>((std::numeric_limits<number_integer_t>::max)()) + 1;
-                curptr++;
-            }
-            else
-            {
-                type = value_t::number_unsigned;
-                max = static_cast<uint64_t>((std::numeric_limits<number_unsigned_t>::max)());
-            }
-
-            // count the significant figures
-            for (; curptr < m_cursor; curptr++)
-            {
-                // quickly skip tests if a digit
-                if (*curptr < '0' || *curptr > '9')
-                {
-                    if (*curptr == '.')
-                    {
-                        // don't count '.' but change to float
-                        type = value_t::number_float;
-                        continue;
-                    }
-                    // assume exponent (if not then will fail parse): change to
-                    // float, stop counting and record exponent details
-                    type = value_t::number_float;
-                    break;
-                }
-
-                // skip if definitely not an integer
-                if (type != value_t::number_float)
-                {
-                    // multiply last value by ten and add the new digit
-                    auto temp = value * 10 + *curptr - '0';
-
-                    // test for overflow
-                    if (temp < value || temp > max)
-                    {
-                        // overflow
-                        type = value_t::number_float;
-                    }
-                    else
-                    {
-                        // no overflow - save it
-                        value = temp;
-                    }
-                }
-            }
-
-            // save the value (if not a float)
-            if (type == value_t::number_unsigned)
-            {
-                result.m_value.number_unsigned = value;
-            }
-            else if (type == value_t::number_integer)
-            {
-                result.m_value.number_integer = -static_cast<number_integer_t>(value);
-            }
-            else
-            {
-                // parse with strtod
-                result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
-            }
-
-            // save the type
-            result.m_type = type;
-        }
-
-      private:
-        /// optional input stream
-        std::istream* m_stream = nullptr;
-        /// the buffer
-        string_t m_buffer;
-        /// the buffer pointer
-        const lexer_char_t* m_content = nullptr;
-        /// pointer to the beginning of the current symbol
-        const lexer_char_t* m_start = nullptr;
-        /// pointer for backtracking information
-        const lexer_char_t* m_marker = nullptr;
-        /// pointer to the current symbol
-        const lexer_char_t* m_cursor = nullptr;
-        /// pointer to the end of the buffer
-        const lexer_char_t* m_limit = nullptr;
-        /// the last token type
-        token_type last_token_type = token_type::end_of_input;
-    };
-
-    /*!
-    @brief syntax analysis
-
-    This class implements a recursive decent parser.
-    */
-    class parser
-    {
-      public:
-        /// constructor for strings
-        parser(const string_t& s, const parser_callback_t cb = nullptr) noexcept
-            : callback(cb), m_lexer(s)
-        {
-            // read first token
-            get_token();
-        }
-
-        /// a parser reading from an input stream
-        parser(std::istream& _is, const parser_callback_t cb = nullptr) noexcept
-            : callback(cb), m_lexer(&_is)
-        {
-            // read first token
-            get_token();
-        }
-
-        /// public parser interface
-        basic_json parse()
-        {
-            basic_json result = parse_internal(true);
-            result.assert_invariant();
-
-            expect(lexer::token_type::end_of_input);
-
-            // return parser result and replace it with null in case the
-            // top-level value was discarded by the callback function
-            return result.is_discarded() ? basic_json() : std::move(result);
-        }
-
-      private:
-        /// the actual parser
-        basic_json parse_internal(bool keep)
-        {
-            auto result = basic_json(value_t::discarded);
-
-            switch (last_token)
-            {
-                case lexer::token_type::begin_object:
-                {
-                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::object_start, result))))
-                    {
-                        // explicitly set result to object to cope with {}
-                        result.m_type = value_t::object;
-                        result.m_value = value_t::object;
-                    }
-
-                    // read next token
-                    get_token();
-
-                    // closing } -> we are done
-                    if (last_token == lexer::token_type::end_object)
-                    {
-                        get_token();
-                        if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
-                        {
-                            result = basic_json(value_t::discarded);
-                        }
-                        return result;
-                    }
-
-                    // no comma is expected here
-                    unexpect(lexer::token_type::value_separator);
-
-                    // otherwise: parse key-value pairs
-                    do
-                    {
-                        // ugly, but could be fixed with loop reorganization
-                        if (last_token == lexer::token_type::value_separator)
-                        {
-                            get_token();
-                        }
-
-                        // store key
-                        expect(lexer::token_type::value_string);
-                        const auto key = m_lexer.get_string();
-
-                        bool keep_tag = false;
-                        if (keep)
-                        {
-                            if (callback)
-                            {
-                                basic_json k(key);
-                                keep_tag = callback(depth, parse_event_t::key, k);
-                            }
-                            else
-                            {
-                                keep_tag = true;
-                            }
-                        }
-
-                        // parse separator (:)
-                        get_token();
-                        expect(lexer::token_type::name_separator);
-
-                        // parse and add value
-                        get_token();
-                        auto value = parse_internal(keep);
-                        if (keep and keep_tag and not value.is_discarded())
-                        {
-                            result[key] = std::move(value);
-                        }
-                    }
-                    while (last_token == lexer::token_type::value_separator);
-
-                    // closing }
-                    expect(lexer::token_type::end_object);
-                    get_token();
-                    if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
-                    {
-                        result = basic_json(value_t::discarded);
-                    }
-
-                    return result;
-                }
-
-                case lexer::token_type::begin_array:
-                {
-                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::array_start, result))))
-                    {
-                        // explicitly set result to object to cope with []
-                        result.m_type = value_t::array;
-                        result.m_value = value_t::array;
-                    }
-
-                    // read next token
-                    get_token();
-
-                    // closing ] -> we are done
-                    if (last_token == lexer::token_type::end_array)
-                    {
-                        get_token();
-                        if (callback and not callback(--depth, parse_event_t::array_end, result))
-                        {
-                            result = basic_json(value_t::discarded);
-                        }
-                        return result;
-                    }
-
-                    // no comma is expected here
-                    unexpect(lexer::token_type::value_separator);
-
-                    // otherwise: parse values
-                    do
-                    {
-                        // ugly, but could be fixed with loop reorganization
-                        if (last_token == lexer::token_type::value_separator)
-                        {
-                            get_token();
-                        }
-
-                        // parse value
-                        auto value = parse_internal(keep);
-                        if (keep and not value.is_discarded())
-                        {
-                            result.push_back(std::move(value));
-                        }
-                    }
-                    while (last_token == lexer::token_type::value_separator);
-
-                    // closing ]
-                    expect(lexer::token_type::end_array);
-                    get_token();
-                    if (keep and callback and not callback(--depth, parse_event_t::array_end, result))
-                    {
-                        result = basic_json(value_t::discarded);
-                    }
-
-                    return result;
-                }
-
-                case lexer::token_type::literal_null:
-                {
-                    get_token();
-                    result.m_type = value_t::null;
-                    break;
-                }
-
-                case lexer::token_type::value_string:
-                {
-                    const auto s = m_lexer.get_string();
-                    get_token();
-                    result = basic_json(s);
-                    break;
-                }
-
-                case lexer::token_type::literal_true:
-                {
-                    get_token();
-                    result.m_type = value_t::boolean;
-                    result.m_value = true;
-                    break;
-                }
-
-                case lexer::token_type::literal_false:
-                {
-                    get_token();
-                    result.m_type = value_t::boolean;
-                    result.m_value = false;
-                    break;
-                }
-
-                case lexer::token_type::value_number:
-                {
-                    m_lexer.get_number(result);
-                    get_token();
-                    break;
-                }
-
-                default:
-                {
-                    // the last token was unexpected
-                    unexpect(last_token);
-                }
-            }
-
-            if (keep and callback and not callback(depth, parse_event_t::value, result))
-            {
-                result = basic_json(value_t::discarded);
-            }
-            return result;
-        }
-
-        /// get next token from lexer
-        typename lexer::token_type get_token() noexcept
-        {
-            last_token = m_lexer.scan();
-            return last_token;
-        }
-
-        void expect(typename lexer::token_type t) const
-        {
-            if (t != last_token)
-            {
-                std::string error_msg = "parse error - unexpected ";
-                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
-                              "'") :
-                              lexer::token_type_name(last_token));
-                error_msg += "; expected " + lexer::token_type_name(t);
-                throw std::invalid_argument(error_msg);
-            }
-        }
-
-        void unexpect(typename lexer::token_type t) const
-        {
-            if (t == last_token)
-            {
-                std::string error_msg = "parse error - unexpected ";
-                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
-                              "'") :
-                              lexer::token_type_name(last_token));
-                throw std::invalid_argument(error_msg);
-            }
-        }
-
-      private:
-        /// current level of recursion
-        int depth = 0;
-        /// callback function
-        const parser_callback_t callback = nullptr;
-        /// the type of the last read token
-        typename lexer::token_type last_token = lexer::token_type::uninitialized;
-        /// the lexer
-        lexer m_lexer;
-    };
-
-  public:
-    /*!
-    @brief JSON Pointer
-
-    A JSON pointer defines a string syntax for identifying a specific value
-    within a JSON document. It can be used with functions `at` and
-    `operator[]`. Furthermore, JSON pointers are the base for JSON patches.
-
-    @sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
-
-    @since version 2.0.0
-    */
-    class json_pointer
-    {
-        /// allow basic_json to access private members
-        friend class basic_json;
-
-      public:
-        /*!
-        @brief create JSON pointer
-
-        Create a JSON pointer according to the syntax described in
-        [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3).
-
-        @param[in] s  string representing the JSON pointer; if omitted, the
-                      empty string is assumed which references the whole JSON
-                      value
-
-        @throw std::domain_error if reference token is nonempty and does not
-        begin with a slash (`/`); example: `"JSON pointer must be empty or
-        begin with /"`
-        @throw std::domain_error if a tilde (`~`) is not followed by `0`
-        (representing `~`) or `1` (representing `/`); example: `"escape error:
-        ~ must be followed with 0 or 1"`
-
-        @liveexample{The example shows the construction several valid JSON
-        pointers as well as the exceptional behavior.,json_pointer}
-
-        @since version 2.0.0
-        */
-        explicit json_pointer(const std::string& s = "")
-            : reference_tokens(split(s))
-        {}
-
-        /*!
-        @brief return a string representation of the JSON pointer
-
-        @invariant For each JSON pointer `ptr`, it holds:
-        @code {.cpp}
-        ptr == json_pointer(ptr.to_string());
-        @endcode
-
-        @return a string representation of the JSON pointer
-
-        @liveexample{The example shows the result of `to_string`.,
-        json_pointer__to_string}
-
-        @since version 2.0.0
-        */
-        std::string to_string() const noexcept
-        {
-            return std::accumulate(reference_tokens.begin(),
-                                   reference_tokens.end(), std::string{},
-                                   [](const std::string & a, const std::string & b)
-            {
-                return a + "/" + escape(b);
-            });
-        }
-
-        /// @copydoc to_string()
-        operator std::string() const
-        {
-            return to_string();
-        }
-
-      private:
-        /// remove and return last reference pointer
-        std::string pop_back()
-        {
-            if (is_root())
-            {
-                throw std::domain_error("JSON pointer has no parent");
-            }
-
-            auto last = reference_tokens.back();
-            reference_tokens.pop_back();
-            return last;
-        }
-
-        /// return whether pointer points to the root document
-        bool is_root() const
-        {
-            return reference_tokens.empty();
-        }
-
-        json_pointer top() const
-        {
-            if (is_root())
-            {
-                throw std::domain_error("JSON pointer has no parent");
-            }
-
-            json_pointer result = *this;
-            result.reference_tokens = {reference_tokens[0]};
-            return result;
-        }
-
-        /*!
-        @brief create and return a reference to the pointed to value
-
-        @complexity Linear in the number of reference tokens.
-        */
-        reference get_and_create(reference j) const
-        {
-            pointer result = &j;
-
-            // in case no reference tokens exist, return a reference to the
-            // JSON value j which will be overwritten by a primitive value
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (result->m_type)
-                {
-                    case value_t::null:
-                    {
-                        if (reference_token == "0")
-                        {
-                            // start a new array if reference token is 0
-                            result = &result->operator[](0);
-                        }
-                        else
-                        {
-                            // start a new object otherwise
-                            result = &result->operator[](reference_token);
-                        }
-                        break;
-                    }
-
-                    case value_t::object:
-                    {
-                        // create an entry in the object
-                        result = &result->operator[](reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        // create an entry in the array
-                        result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                        break;
-                    }
-
-                    /*
-                    The following code is only reached if there exists a
-                    reference token _and_ the current value is primitive. In
-                    this case, we have an error situation, because primitive
-                    values may only occur as single value; that is, with an
-                    empty list of reference tokens.
-                    */
-                    default:
-                    {
-                        throw std::domain_error("invalid value to unflatten");
-                    }
-                }
-            }
-
-            return *result;
-        }
-
-        /*!
-        @brief return a reference to the pointed to value
-
-        @param[in] ptr  a JSON value
-
-        @return reference to the JSON value pointed to by the JSON pointer
-
-        @complexity Linear in the length of the JSON pointer.
-
-        @throw std::out_of_range      if the JSON pointer can not be resolved
-        @throw std::domain_error      if an array index begins with '0'
-        @throw std::invalid_argument  if an array index was not a number
-        */
-        reference get_unchecked(pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // use unchecked object access
-                        ptr = &ptr->operator[](reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            throw std::domain_error("array index must not begin with '0'");
-                        }
-
-                        if (reference_token == "-")
-                        {
-                            // explicityly treat "-" as index beyond the end
-                            ptr = &ptr->operator[](ptr->m_value.array->size());
-                        }
-                        else
-                        {
-                            // convert array index to number; unchecked access
-                            ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                        }
-                        break;
-                    }
-
-                    default:
-                    {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
-                    }
-                }
-            }
-
-            return *ptr;
-        }
-
-        reference get_checked(pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // note: at performs range check
-                        ptr = &ptr->at(reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" always fails the range check
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
-                        }
-
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            throw std::domain_error("array index must not begin with '0'");
-                        }
-
-                        // note: at performs range check
-                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
-                        break;
-                    }
-
-                    default:
-                    {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
-                    }
-                }
-            }
-
-            return *ptr;
-        }
-
-        /*!
-        @brief return a const reference to the pointed to value
-
-        @param[in] ptr  a JSON value
-
-        @return const reference to the JSON value pointed to by the JSON
-                pointer
-        */
-        const_reference get_unchecked(const_pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // use unchecked object access
-                        ptr = &ptr->operator[](reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" cannot be used for const access
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
-                        }
-
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            throw std::domain_error("array index must not begin with '0'");
-                        }
-
-                        // use unchecked array access
-                        ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                        break;
-                    }
-
-                    default:
-                    {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
-                    }
-                }
-            }
-
-            return *ptr;
-        }
-
-        const_reference get_checked(const_pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // note: at performs range check
-                        ptr = &ptr->at(reference_token);
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" always fails the range check
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
-                        }
-
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            throw std::domain_error("array index must not begin with '0'");
-                        }
-
-                        // note: at performs range check
-                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
-                        break;
-                    }
-
-                    default:
-                    {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
-                    }
-                }
-            }
-
-            return *ptr;
-        }
-
-        /// split the string input to reference tokens
-        static std::vector<std::string> split(std::string reference_string)
-        {
-            std::vector<std::string> result;
-
-            // special case: empty reference string -> no reference tokens
-            if (reference_string.empty())
-            {
-                return result;
-            }
-
-            // check if nonempty reference string begins with slash
-            if (reference_string[0] != '/')
-            {
-                throw std::domain_error("JSON pointer must be empty or begin with '/'");
-            }
-
-            // extract the reference tokens:
-            // - slash: position of the last read slash (or end of string)
-            // - start: position after the previous slash
-            for (
-                // search for the first slash after the first character
-                size_t slash = reference_string.find_first_of("/", 1),
-                // set the beginning of the first reference token
-                start = 1;
-                // we can stop if start == string::npos+1 = 0
-                start != 0;
-                // set the beginning of the next reference token
-                // (will eventually be 0 if slash == std::string::npos)
-                start = slash + 1,
-                // find next slash
-                slash = reference_string.find_first_of("/", start))
-            {
-                // use the text between the beginning of the reference token
-                // (start) and the last slash (slash).
-                auto reference_token = reference_string.substr(start, slash - start);
-
-                // check reference tokens are properly escaped
-                for (size_t pos = reference_token.find_first_of("~");
-                        pos != std::string::npos;
-                        pos = reference_token.find_first_of("~", pos + 1))
-                {
-                    assert(reference_token[pos] == '~');
-
-                    // ~ must be followed by 0 or 1
-                    if (pos == reference_token.size() - 1 or
-                            (reference_token[pos + 1] != '0' and
-                             reference_token[pos + 1] != '1'))
-                    {
-                        throw std::domain_error("escape error: '~' must be followed with '0' or '1'");
-                    }
-                }
-
-                // finally, store the reference token
-                unescape(reference_token);
-                result.push_back(reference_token);
-            }
-
-            return result;
-        }
-
-      private:
-        /*!
-        @brief replace all occurrences of a substring by another string
-
-        @param[in,out] s  the string to manipulate
-        @param[in]     f  the substring to replace with @a t
-        @param[in]     t  the string to replace @a f
-
-        @return The string @a s where all occurrences of @a f are replaced
-                with @a t.
-
-        @pre The search string @a f must not be empty.
-
-        @since version 2.0.0
-        */
-        static void replace_substring(std::string& s,
-                                      const std::string& f,
-                                      const std::string& t)
-        {
-            assert(not f.empty());
-
-            for (
-                size_t pos = s.find(f);         // find first occurrence of f
-                pos != std::string::npos;       // make sure f was found
-                s.replace(pos, f.size(), t),    // replace with t
-                pos = s.find(f, pos + t.size()) // find next occurrence of f
-            );
-        }
-
-        /// escape tilde and slash
-        static std::string escape(std::string s)
-        {
-            // escape "~"" to "~0" and "/" to "~1"
-            replace_substring(s, "~", "~0");
-            replace_substring(s, "/", "~1");
-            return s;
-        }
-
-        /// unescape tilde and slash
-        static void unescape(std::string& s)
-        {
-            // first transform any occurrence of the sequence '~1' to '/'
-            replace_substring(s, "~1", "/");
-            // then transform any occurrence of the sequence '~0' to '~'
-            replace_substring(s, "~0", "~");
-        }
-
-        /*!
-        @param[in] reference_string  the reference string to the current value
-        @param[in] value             the value to consider
-        @param[in,out] result        the result object to insert values to
-
-        @note Empty objects or arrays are flattened to `null`.
-        */
-        static void flatten(const std::string& reference_string,
-                            const basic_json& value,
-                            basic_json& result)
-        {
-            switch (value.m_type)
-            {
-                case value_t::array:
-                {
-                    if (value.m_value.array->empty())
-                    {
-                        // flatten empty array as null
-                        result[reference_string] = nullptr;
-                    }
-                    else
-                    {
-                        // iterate array and use index as reference string
-                        for (size_t i = 0; i < value.m_value.array->size(); ++i)
-                        {
-                            flatten(reference_string + "/" + std::to_string(i),
-                                    value.m_value.array->operator[](i), result);
-                        }
-                    }
-                    break;
-                }
-
-                case value_t::object:
-                {
-                    if (value.m_value.object->empty())
-                    {
-                        // flatten empty object as null
-                        result[reference_string] = nullptr;
-                    }
-                    else
-                    {
-                        // iterate object and use keys as reference string
-                        for (const auto& element : *value.m_value.object)
-                        {
-                            flatten(reference_string + "/" + escape(element.first),
-                                    element.second, result);
-                        }
-                    }
-                    break;
-                }
-
-                default:
-                {
-                    // add primitive value with its reference string
-                    result[reference_string] = value;
-                    break;
-                }
-            }
-        }
-
-        /*!
-        @param[in] value  flattened JSON
-
-        @return unflattened JSON
-        */
-        static basic_json unflatten(const basic_json& value)
-        {
-            if (not value.is_object())
-            {
-                throw std::domain_error("only objects can be unflattened");
-            }
-
-            basic_json result;
-
-            // iterate the JSON object values
-            for (const auto& element : *value.m_value.object)
-            {
-                if (not element.second.is_primitive())
-                {
-                    throw std::domain_error("values in object must be primitive");
-                }
-
-                // assign value to reference pointed to by JSON pointer; Note
-                // that if the JSON pointer is "" (i.e., points to the whole
-                // value), function get_and_create returns a reference to
-                // result itself. An assignment will then create a primitive
-                // value.
-                json_pointer(element.first).get_and_create(result) = element.second;
-            }
-
-            return result;
-        }
-
-      private:
-        /// the reference tokens
-        std::vector<std::string> reference_tokens {};
-    };
-
-    //////////////////////////
-    // JSON Pointer support //
-    //////////////////////////
-
-    /// @name JSON Pointer functions
-    /// @{
-
-    /*!
-    @brief access specified element via JSON Pointer
-
-    Uses a JSON pointer to retrieve a reference to the respective JSON value.
-    No bound checking is performed. Similar to @ref operator[](const typename
-    object_t::key_type&), `null` values are created in arrays and objects if
-    necessary.
-
-    In particular:
-    - If the JSON pointer points to an object key that does not exist, it
-      is created an filled with a `null` value before a reference to it
-      is returned.
-    - If the JSON pointer points to an array index that does not exist, it
-      is created an filled with a `null` value before a reference to it
-      is returned. All indices between the current maximum and the given
-      index are also filled with `null`.
-    - The special value `-` is treated as a synonym for the index past the
-      end.
-
-    @param[in] ptr  a JSON pointer
-
-    @return reference to the element pointed to by @a ptr
-
-    @complexity Constant.
-
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
-
-    @liveexample{The behavior is shown in the example.,operatorjson_pointer}
-
-    @since version 2.0.0
-    */
-    reference operator[](const json_pointer& ptr)
-    {
-        return ptr.get_unchecked(this);
-    }
-
-    /*!
-    @brief access specified element via JSON Pointer
-
-    Uses a JSON pointer to retrieve a reference to the respective JSON value.
-    No bound checking is performed. The function does not change the JSON
-    value; no `null` values are created. In particular, the the special value
-    `-` yields an exception.
-
-    @param[in] ptr  JSON pointer to the desired element
-
-    @return const reference to the element pointed to by @a ptr
-
-    @complexity Constant.
-
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
-
-    @liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
-
-    @since version 2.0.0
-    */
-    const_reference operator[](const json_pointer& ptr) const
-    {
-        return ptr.get_unchecked(this);
-    }
-
-    /*!
-    @brief access specified element via JSON Pointer
-
-    Returns a reference to the element at with specified JSON pointer @a ptr,
-    with bounds checking.
-
-    @param[in] ptr  JSON pointer to the desired element
-
-    @return reference to the element pointed to by @a ptr
-
-    @complexity Constant.
-
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
-
-    @liveexample{The behavior is shown in the example.,at_json_pointer}
-
-    @since version 2.0.0
-    */
-    reference at(const json_pointer& ptr)
-    {
-        return ptr.get_checked(this);
-    }
-
-    /*!
-    @brief access specified element via JSON Pointer
-
-    Returns a const reference to the element at with specified JSON pointer @a
-    ptr, with bounds checking.
-
-    @param[in] ptr  JSON pointer to the desired element
-
-    @return reference to the element pointed to by @a ptr
-
-    @complexity Constant.
-
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
-
-    @liveexample{The behavior is shown in the example.,at_json_pointer_const}
-
-    @since version 2.0.0
-    */
-    const_reference at(const json_pointer& ptr) const
-    {
-        return ptr.get_checked(this);
-    }
-
-    /*!
-    @brief return flattened JSON value
-
-    The function creates a JSON object whose keys are JSON pointers (see [RFC
-    6901](https://tools.ietf.org/html/rfc6901)) and whose values are all
-    primitive. The original JSON value can be restored using the @ref
-    unflatten() function.
-
-    @return an object that maps JSON pointers to primitve values
-
-    @note Empty objects and arrays are flattened to `null` and will not be
-          reconstructed correctly by the @ref unflatten() function.
-
-    @complexity Linear in the size the JSON value.
-
-    @liveexample{The following code shows how a JSON object is flattened to an
-    object whose keys consist of JSON pointers.,flatten}
-
-    @sa @ref unflatten() for the reverse function
-
-    @since version 2.0.0
-    */
-    basic_json flatten() const
-    {
-        basic_json result(value_t::object);
-        json_pointer::flatten("", *this, result);
-        return result;
-    }
-
-    /*!
-    @brief unflatten a previously flattened JSON value
-
-    The function restores the arbitrary nesting of a JSON value that has been
-    flattened before using the @ref flatten() function. The JSON value must
-    meet certain constraints:
-    1. The value must be an object.
-    2. The keys must be JSON pointers (see
-       [RFC 6901](https://tools.ietf.org/html/rfc6901))
-    3. The mapped values must be primitive JSON types.
-
-    @return the original JSON from a flattened version
-
-    @note Empty objects and arrays are flattened by @ref flatten() to `null`
-          values and can not unflattened to their original type. Apart from
-          this example, for a JSON value `j`, the following is always true:
-          `j == j.flatten().unflatten()`.
-
-    @complexity Linear in the size the JSON value.
-
-    @liveexample{The following code shows how a flattened JSON object is
-    unflattened into the original nested JSON object.,unflatten}
-
-    @sa @ref flatten() for the reverse function
-
-    @since version 2.0.0
-    */
-    basic_json unflatten() const
-    {
-        return json_pointer::unflatten(*this);
-    }
-
-    /// @}
-
-    //////////////////////////
-    // JSON Patch functions //
-    //////////////////////////
-
-    /// @name JSON Patch functions
-    /// @{
-
-    /*!
-    @brief applies a JSON patch
-
-    [JSON Patch](http://jsonpatch.com) defines a JSON document structure for
-    expressing a sequence of operations to apply to a JSON) document. With
-    this funcion, a JSON Patch is applied to the current JSON value by
-    executing all operations from the patch.
-
-    @param[in] json_patch  JSON patch document
-    @return patched document
-
-    @note The application of a patch is atomic: Either all operations succeed
-          and the patched document is returned or an exception is thrown. In
-          any case, the original value is not changed: the patch is applied
-          to a copy of the value.
-
-    @throw std::out_of_range if a JSON pointer inside the patch could not
-    be resolved successfully in the current JSON value; example: `"key baz
-    not found"`
-    @throw invalid_argument if the JSON patch is malformed (e.g., mandatory
-    attributes are missing); example: `"operation add must have member path"`
-
-    @complexity Linear in the size of the JSON value and the length of the
-    JSON patch. As usually only a fraction of the JSON value is affected by
-    the patch, the complexity can usually be neglected.
-
-    @liveexample{The following code shows how a JSON patch is applied to a
-    value.,patch}
-
-    @sa @ref diff -- create a JSON patch by comparing two JSON values
-
-    @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
-    @sa [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
-
-    @since version 2.0.0
-    */
-    basic_json patch(const basic_json& json_patch) const
-    {
-        // make a working copy to apply the patch to
-        basic_json result = *this;
-
-        // the valid JSON Patch operations
-        enum class patch_operations {add, remove, replace, move, copy, test, invalid};
-
-        const auto get_op = [](const std::string op)
-        {
-            if (op == "add")
-            {
-                return patch_operations::add;
-            }
-            if (op == "remove")
-            {
-                return patch_operations::remove;
-            }
-            if (op == "replace")
-            {
-                return patch_operations::replace;
-            }
-            if (op == "move")
-            {
-                return patch_operations::move;
-            }
-            if (op == "copy")
-            {
-                return patch_operations::copy;
-            }
-            if (op == "test")
-            {
-                return patch_operations::test;
-            }
-
-            return patch_operations::invalid;
-        };
-
-        // wrapper for "add" operation; add value at ptr
-        const auto operation_add = [&result](json_pointer & ptr, basic_json val)
-        {
-            // adding to the root of the target document means replacing it
-            if (ptr.is_root())
-            {
-                result = val;
-            }
-            else
-            {
-                // make sure the top element of the pointer exists
-                json_pointer top_pointer = ptr.top();
-                if (top_pointer != ptr)
-                {
-                    basic_json& x = result.at(top_pointer);
-                }
-
-                // get reference to parent of JSON pointer ptr
-                const auto last_path = ptr.pop_back();
-                basic_json& parent = result[ptr];
-
-                switch (parent.m_type)
-                {
-                    case value_t::null:
-                    case value_t::object:
-                    {
-                        // use operator[] to add value
-                        parent[last_path] = val;
-                        break;
-                    }
-
-                    case value_t::array:
-                    {
-                        if (last_path == "-")
-                        {
-                            // special case: append to back
-                            parent.push_back(val);
-                        }
-                        else
-                        {
-                            const auto idx = std::stoi(last_path);
-                            if (static_cast<size_type>(idx) > parent.size())
-                            {
-                                // avoid undefined behavior
-                                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
-                            }
-                            else
-                            {
-                                // default case: insert add offset
-                                parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
-                            }
-                        }
-                        break;
-                    }
-
-                    default:
-                    {
-                        // if there exists a parent it cannot be primitive
-                        assert(false);  // LCOV_EXCL_LINE
-                    }
-                }
-            }
-        };
-
-        // wrapper for "remove" operation; remove value at ptr
-        const auto operation_remove = [&result](json_pointer & ptr)
-        {
-            // get reference to parent of JSON pointer ptr
-            const auto last_path = ptr.pop_back();
-            basic_json& parent = result.at(ptr);
-
-            // remove child
-            if (parent.is_object())
-            {
-                // perform range check
-                auto it = parent.find(last_path);
-                if (it != parent.end())
-                {
-                    parent.erase(it);
-                }
-                else
-                {
-                    throw std::out_of_range("key '" + last_path + "' not found");
-                }
-            }
-            else if (parent.is_array())
-            {
-                // note erase performs range check
-                parent.erase(static_cast<size_type>(std::stoi(last_path)));
-            }
-        };
-
-        // type check
-        if (not json_patch.is_array())
-        {
-            // a JSON patch must be an array of objects
-            throw std::invalid_argument("JSON patch must be an array of objects");
-        }
-
-        // iterate and apply th eoperations
-        for (const auto& val : json_patch)
-        {
-            // wrapper to get a value for an operation
-            const auto get_value = [&val](const std::string & op,
-                                          const std::string & member,
-                                          bool string_type) -> basic_json&
-            {
-                // find value
-                auto it = val.m_value.object->find(member);
-
-                // context-sensitive error message
-                const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";
-
-                // check if desired value is present
-                if (it == val.m_value.object->end())
-                {
-                    throw std::invalid_argument(error_msg + " must have member '" + member + "'");
-                }
-
-                // check if result is of type string
-                if (string_type and not it->second.is_string())
-                {
-                    throw std::invalid_argument(error_msg + " must have string member '" + member + "'");
-                }
-
-                // no error: return value
-                return it->second;
-            };
-
-            // type check
-            if (not val.is_object())
-            {
-                throw std::invalid_argument("JSON patch must be an array of objects");
-            }
-
-            // collect mandatory members
-            const std::string op = get_value("op", "op", true);
-            const std::string path = get_value(op, "path", true);
-            json_pointer ptr(path);
-
-            switch (get_op(op))
-            {
-                case patch_operations::add:
-                {
-                    operation_add(ptr, get_value("add", "value", false));
-                    break;
-                }
-
-                case patch_operations::remove:
-                {
-                    operation_remove(ptr);
-                    break;
-                }
-
-                case patch_operations::replace:
-                {
-                    // the "path" location must exist - use at()
-                    result.at(ptr) = get_value("replace", "value", false);
-                    break;
-                }
-
-                case patch_operations::move:
-                {
-                    const std::string from_path = get_value("move", "from", true);
-                    json_pointer from_ptr(from_path);
-
-                    // the "from" location must exist - use at()
-                    basic_json v = result.at(from_ptr);
-
-                    // The move operation is functionally identical to a
-                    // "remove" operation on the "from" location, followed
-                    // immediately by an "add" operation at the target
-                    // location with the value that was just removed.
-                    operation_remove(from_ptr);
-                    operation_add(ptr, v);
-                    break;
-                }
-
-                case patch_operations::copy:
-                {
-                    const std::string from_path = get_value("copy", "from", true);;
-                    const json_pointer from_ptr(from_path);
-
-                    // the "from" location must exist - use at()
-                    result[ptr] = result.at(from_ptr);
-                    break;
-                }
-
-                case patch_operations::test:
-                {
-                    bool success = false;
-                    try
-                    {
-                        // check if "value" matches the one at "path"
-                        // the "path" location must exist - use at()
-                        success = (result.at(ptr) == get_value("test", "value", false));
-                    }
-                    catch (std::out_of_range&)
-                    {
-                        // ignore out of range errors: success remains false
-                    }
-
-                    // throw an exception if test fails
-                    if (not success)
-                    {
-                        throw std::domain_error("unsuccessful: " + val.dump());
-                    }
-
-                    break;
-                }
-
-                case patch_operations::invalid:
-                {
-                    // op must be "add", "remove", "replace", "move", "copy", or
-                    // "test"
-                    throw std::invalid_argument("operation value '" + op + "' is invalid");
-                }
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief creates a diff as a JSON patch
-
-    Creates a [JSON Patch](http://jsonpatch.com) so that value @a source can
-    be changed into the value @a target by calling @ref patch function.
-
-    @invariant For two JSON values @a source and @a target, the following code
-    yields always `true`:
-    @code {.cpp}
-    source.patch(diff(source, target)) == target;
-    @endcode
-
-    @note Currently, only `remove`, `add`, and `replace` operations are
-          generated.
-
-    @param[in] source  JSON value to copare from
-    @param[in] target  JSON value to copare against
-    @param[in] path    helper value to create JSON pointers
-
-    @return a JSON patch to convert the @a source to @a target
-
-    @complexity Linear in the lengths of @a source and @a target.
-
-    @liveexample{The following code shows how a JSON patch is created as a
-    diff for two JSON values.,diff}
-
-    @sa @ref patch -- apply a JSON patch
-
-    @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
-
-    @since version 2.0.0
-    */
-    static basic_json diff(const basic_json& source,
-                           const basic_json& target,
-                           std::string path = "")
-    {
-        // the patch
-        basic_json result(value_t::array);
-
-        // if the values are the same, return empty patch
-        if (source == target)
-        {
-            return result;
-        }
-
-        if (source.type() != target.type())
-        {
-            // different types: replace value
-            result.push_back(
-            {
-                {"op", "replace"},
-                {"path", path},
-                {"value", target}
-            });
-        }
-        else
-        {
-            switch (source.type())
-            {
-                case value_t::array:
-                {
-                    // first pass: traverse common elements
-                    size_t i = 0;
-                    while (i < source.size() and i < target.size())
-                    {
-                        // recursive call to compare array values at index i
-                        auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
-                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
-                        ++i;
-                    }
-
-                    // i now reached the end of at least one array
-                    // in a second pass, traverse the remaining elements
-
-                    // remove my remaining elements
-                    const auto end_index = static_cast<difference_type>(result.size());
-                    while (i < source.size())
-                    {
-                        // add operations in reverse order to avoid invalid
-                        // indices
-                        result.insert(result.begin() + end_index, object(
-                        {
-                            {"op", "remove"},
-                            {"path", path + "/" + std::to_string(i)}
-                        }));
-                        ++i;
-                    }
-
-                    // add other remaining elements
-                    while (i < target.size())
-                    {
-                        result.push_back(
-                        {
-                            {"op", "add"},
-                            {"path", path + "/" + std::to_string(i)},
-                            {"value", target[i]}
-                        });
-                        ++i;
-                    }
-
-                    break;
-                }
-
-                case value_t::object:
-                {
-                    // first pass: traverse this object's elements
-                    for (auto it = source.begin(); it != source.end(); ++it)
-                    {
-                        // escape the key name to be used in a JSON patch
-                        const auto key = json_pointer::escape(it.key());
-
-                        if (target.find(it.key()) != target.end())
-                        {
-                            // recursive call to compare object values at key it
-                            auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key);
-                            result.insert(result.end(), temp_diff.begin(), temp_diff.end());
-                        }
-                        else
-                        {
-                            // found a key that is not in o -> remove it
-                            result.push_back(object(
-                            {
-                                {"op", "remove"},
-                                {"path", path + "/" + key}
-                            }));
-                        }
-                    }
-
-                    // second pass: traverse other object's elements
-                    for (auto it = target.begin(); it != target.end(); ++it)
-                    {
-                        if (source.find(it.key()) == source.end())
-                        {
-                            // found a key that is not in this -> add it
-                            const auto key = json_pointer::escape(it.key());
-                            result.push_back(
-                            {
-                                {"op", "add"},
-                                {"path", path + "/" + key},
-                                {"value", it.value()}
-                            });
-                        }
-                    }
-
-                    break;
-                }
-
-                default:
-                {
-                    // both primitive type: replace value
-                    result.push_back(
-                    {
-                        {"op", "replace"},
-                        {"path", path},
-                        {"value", target}
-                    });
-                    break;
-                }
-            }
-        }
-
-        return result;
-    }
-
-    /// @}
-};
-
-
-/////////////
-// presets //
-/////////////
-
-/*!
-@brief default JSON class
-
-This type is the default specialization of the @ref basic_json class which
-uses the standard template types.
-
-@since version 1.0.0
-*/
-using json = basic_json<>;
-}
-
-
-///////////////////////
-// nonmember support //
-///////////////////////
-
-// specialization of std::swap, and std::hash
-namespace std
-{
-/*!
-@brief exchanges the values of two JSON objects
-
-@since version 1.0.0
-*/
-template <>
-inline void swap(nlohmann::json& j1,
-                 nlohmann::json& j2) noexcept(
-                     is_nothrow_move_constructible<nlohmann::json>::value and
-                     is_nothrow_move_assignable<nlohmann::json>::value
-                 )
-{
-    j1.swap(j2);
-}
-
-/// hash value for JSON objects
-template <>
-struct hash<nlohmann::json>
-{
-    /*!
-    @brief return a hash value for a JSON object
-
-    @since version 1.0.0
-    */
-    std::size_t operator()(const nlohmann::json& j) const
-    {
-        // a naive hashing via the string representation
-        const auto& h = hash<nlohmann::json::string_t>();
-        return h(j.dump());
-    }
-};
-}
-
-/*!
-@brief user-defined string literal for JSON values
-
-This operator implements a user-defined string literal for JSON objects. It
-can be used by adding `"_json"` to a string literal and returns a JSON object
-if no parse error occurred.
-
-@param[in] s  a string representation of a JSON object
-@return a JSON object
-
-@since version 1.0.0
-*/
-inline nlohmann::json operator "" _json(const char* s, std::size_t)
-{
-    return nlohmann::json::parse(reinterpret_cast<const nlohmann::json::string_t::value_type*>(s));
-}
-
-/*!
-@brief user-defined string literal for JSON pointer
-
-This operator implements a user-defined string literal for JSON Pointers. It
-can be used by adding `"_json"` to a string literal and returns a JSON pointer
-object if no parse error occurred.
-
-@param[in] s  a string representation of a JSON Pointer
-@return a JSON pointer object
-
-@since version 2.0.0
-*/
-inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t)
-{
-    return nlohmann::json::json_pointer(s);
-}
-
-// restore GCC/clang diagnostic settings
-#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-    #pragma GCC diagnostic pop
-#endif
-
-#endif
diff --git a/ext/offbase/offbase.hpp b/ext/offbase/offbase.hpp
deleted file mode 100644
index acce8c4a..00000000
--- a/ext/offbase/offbase.hpp
+++ /dev/null
@@ -1,393 +0,0 @@
-/*
- * Offbase: a super-minimal in-filesystem JSON object persistence store
- */
-
-#ifndef OFFBASE_HPP__
-#define OFFBASE_HPP__
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <dirent.h>
-#include <unistd.h>
-#include <sys/stat.h>
-
-#include <vector>
-#include <string>
-#include <map>
-
-#include "json/json.hpp"
-
-#define OFFBASE_PATH_SEP "/"
-
-/**
- * A super-minimal in-filesystem JSON object persistence store
- */
-class offbase : public nlohmann::json
-{
-public:
-	offbase(const char *p) :
-		nlohmann::json(nlohmann::json::object()),
-		_path(p),
-		_saved(nlohmann::json::object())
-	{
-		this->load();
-	}
-
-	~offbase()
-	{
-		this->commit();
-	}
-
-	/**
-	 * Load this instance from disk, clearing any existing contents first
-	 *
-	 * If the 'errors' vector is NULL, false is returned and reading aborts
-	 * on any error. If this parameter is non-NULL the paths of errors will
-	 * be added to the vector and reading will continue. False will only be
-	 * returned on really big errors like no path being defined.
-	 *
-	 * @param errors If specified, fill this vector with the paths to any objects that fail read
-	 * @return True on success, false on fatal error
-	 */
-	inline bool load(std::vector<std::string> *errors = (std::vector<std::string> *)0)
-	{
-		if (!_path.length())
-			return false;
-		*this = nlohmann::json::object();
-		if (!_loadObj(_path,*this,errors))
-			return false;
-		_saved = *(reinterpret_cast<nlohmann::json *>(this));
-		return true;
-	}
-
-	/**
-	 * Commit any pending changes to this object to disk
-	 *
-	 * @return True on success or false if an I/O error occurred
-	 */
-	inline bool commit(std::vector<std::string> *errors = (std::vector<std::string> *)0)
-	{
-		if (!_path.length())
-			return false;
-		if (!_commitObj(_path,*this,&_saved,errors))
-			return false;
-		_saved = *(reinterpret_cast<nlohmann::json *>(this));
-		return true;
-	}
-
-	static inline std::string escapeKey(const std::string &k)
-	{
-		std::string e;
-		const char *ptr = k.data();
-		const char *eof = ptr + k.length();
-		char tmp[8];
-		while (ptr != eof) {
-			if ( ((*ptr >= 'a')&&(*ptr <= 'z')) || ((*ptr >= 'A')&&(*ptr <= 'Z')) || ((*ptr >= '0')&&(*ptr <= '9')) || (*ptr == '.') || (*ptr == '_') || (*ptr == '-') || (*ptr == ',') )
-				e.push_back(*ptr);
-			else {
-				snprintf(tmp,sizeof(tmp),"~%.2x",(unsigned int)*ptr);
-				e.append(tmp);
-			}
-			++ptr;
-		}
-		return e;
-	}
-
-	static inline std::string unescapeKey(const std::string &k)
-	{
-		std::string u;
-		const char *ptr = k.data();
-		const char *eof = ptr + k.length();
-		char tmp[8];
-		while (ptr != eof) {
-			if (*ptr == '~') {
-				if (++ptr == eof) break;
-				tmp[0] = *ptr;
-				if (++ptr == eof) break;
-				tmp[1] = *(ptr++);
-				tmp[2] = (char)0;
-				u.push_back((char)strtol(tmp,(char **)0,16));
-			} else {
-				u.push_back(*(ptr++));
-			}
-		}
-		return u;
-	}
-
-private:
-	static inline bool _readFile(const char *path,std::string &buf)
-	{
-		char tmp[4096];
-		FILE *f = fopen(path,"rb");
-		if (f) {
-			for(;;) {
-				long n = (long)fread(tmp,1,sizeof(tmp),f);
-				if (n > 0)
-					buf.append(tmp,n);
-				else break;
-			}
-			fclose(f);
-			return true;
-		}
-		return false;
-	}
-
-	static inline bool _loadArr(const std::string &path,nlohmann::json &arr,std::vector<std::string> *errors)
-	{
-		std::map<unsigned long,nlohmann::json> atmp; // place into an ordered container first because filesystem does not guarantee this
-
-		struct dirent dbuf;
-		struct dirent *de;
-		DIR *d = opendir(path.c_str());
-		if (d) {
-			while (!readdir_d(d,&dbuf,&de)) {
-				if (!de) break;
-				const std::string name(de->d_name);
-				if (name.length() != 12) continue; // array entries are XXXXXXXXXX.T
-				if (name[name.length()-2] == '.') {
-					if (name[name.length()-1] == 'V') {
-						std::string buf;
-						if (_readFile((path + OFFBASE_PATH_SEP + name).c_str(),buf)) {
-							try {
-								atmp[strtoul(name.substr(0,10).c_str(),(char **)0,16)] = nlohmann::json::parse(buf);
-							} catch ( ... ) {
-								if (errors) {
-									errors->push_back(path + OFFBASE_PATH_SEP + name);
-								} else {
-									return false;
-								}
-							}
-						} else if (errors) {
-							errors->push_back(path + OFFBASE_PATH_SEP + name);
-						} else return false;
-					} else if (name[name.length()-1] == 'O') {
-						if (!_loadObj(path + OFFBASE_PATH_SEP + name,atmp[strtoul(name.substr(0,10).c_str(),(char **)0,16)] = nlohmann::json::object(),errors))
-							return false;
-					} else if (name[name.length()-1] == 'A') {
-						if (!_loadArr(path + OFFBASE_PATH_SEP + name,atmp[strtoul(name.substr(0,10).c_str(),(char **)0,16)] = nlohmann::json::array(),errors))
-							return false;
-					}
-				}
-			}
-			closedir(d);
-		} else if (errors) {
-			errors->push_back(path);
-		} else return false;
-
-		if (atmp.size() > 0) {
-			unsigned long lasti = 0;
-			for(std::map<unsigned long,nlohmann::json>::iterator i(atmp.begin());i!=atmp.end();++i) {
-				for(unsigned long k=lasti;k<i->first;++k) // fill any gaps with nulls
-					arr.push_back(nlohmann::json(std::nullptr_t));
-				lasti = i->first;
-				arr.push_back(i->second);
-			}
-		}
-
-		return true;
-	}
-
-	static inline bool _loadObj(const std::string &path,nlohmann::json &obj,std::vector<std::string> *errors)
-	{
-		struct dirent dbuf;
-		struct dirent *de;
-		DIR *d = opendir(path.c_str());
-		if (d) {
-			while (!readdir_d(d,&dbuf,&de)) {
-				if (!de) break;
-				if ((strcmp(de->d_name,".") == 0)||(strcmp(de->d_name,"..") == 0)) continue; // sanity check
-				const std::string name(de->d_name);
-				if (name.length() <= 2) continue;
-				if (name[name.length()-2] == '.') {
-					if (name[name.length()-1] == 'V') {
-						std::string buf;
-						if (_readFile((path + OFFBASE_PATH_SEP + name).c_str(),buf)) {
-							try {
-								obj[unescapeKey(name)] = nlohmann::json::parse(buf);
-							} catch ( ... ) {
-								if (errors) {
-									errors->push_back(path + OFFBASE_PATH_SEP + name);
-								} else {
-									return false;
-								}
-							}
-						} else if (errors) {
-							errors->push_back(path + OFFBASE_PATH_SEP + name);
-						} else return false;
-					} else if (name[name.length()-1] == 'O') {
-						if (!_loadObj(path + OFFBASE_PATH_SEP + name,obj[unescapeKey(name)] = nlohmann::json::object(),errors))
-							return false;
-					} else if (name[name.length()-1] == 'A') {
-						if (!_loadArr(path + OFFBASE_PATH_SEP + name,obj[unescapeKey(name)] = nlohmann::json::array(),errors))
-							return false;
-					}
-				}
-			}
-			closedir(d);
-		} else if (errors) {
-			errors->push_back(path);
-		} else return false;
-		return true;
-	}
-
-	static inline void _rmDashRf(const std::string &path)
-	{
-		struct dirent dbuf;
-		struct dirent *de;
-		DIR *d = opendir(path.c_str());
-		if (d) {
-			while (!readdir_r(d,&dbuf,&de)) {
-				if (!de) break;
-				if ((strcmp(de->d_name,".") == 0)||(strcmp(de->d_name,"..") == 0)) continue; // sanity check
-				const std::string full(path + OFFBASE_PATH_SEP + de->d_name);
-				if (unlink(full.c_str())) {
-					_rmDashRf(full);
-					rmdir(full.c_str());
-				}
-			}
-			closedir(d);
-		}
-		rmdir(path.c_str());
-	}
-
-	static inline bool _commitArr(const std::string &path,const nlohmann::json &arr,const nlohmann::json *previous,std::vector<std::string> *errors)
-	{
-		char tmp[32];
-
-		if (!arr.is_array())
-			return false;
-
-		mkdir(path.c_str(),0755);
-
-		for(unsigned long i=0;i<(unsigned long)arr.size();++i) {
-			const nlohmann::json &value = arr[i];
-
-			const nlohmann::json *next = (const nlohmann::json *)0;
-			if ((previous)&&(previous->is_array())&&(i < previous->size())) {
-				next = &((*previous)[i]);
-				if (*next == value)
-					continue;
-			}
-
-			if (value.is_object()) {
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.O",OFFBASE_PATH_SEP,i);
-				if (!_commitObj(path + tmp,value,next,errors))
-					return false;
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.V",OFFBASE_PATH_SEP,i);
-				unlink((path + tmp).c_str());
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.A",OFFBASE_PATH_SEP,i);
-				_rmDashRf(path + tmp);
-			} else if (value.is_array()) {
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.A",OFFBASE_PATH_SEP,i);
-				if (!_commitArr(path + tmp,value,next,errors))
-					return false;
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.O",OFFBASE_PATH_SEP,i);
-				_rmDashRf(path + tmp);
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.V",OFFBASE_PATH_SEP,i);
-				unlink((path + tmp).c_str());
-			} else {
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.V",OFFBASE_PATH_SEP,i);
-				FILE *f = fopen((path + tmp).c_str(),"w");
-				if (f) {
-					const std::string v(value.dump());
-					if (fwrite(v.c_str(),v.length(),1,f) != 1) {
-						fclose(f);
-						return false;
-					} else {
-						fclose(f);
-					}
-				} else {
-					return false;
-				}
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.A",OFFBASE_PATH_SEP,i);
-				_rmDashRf(path + tmp);
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.O",OFFBASE_PATH_SEP,i);
-				_rmDashRf(path + tmp);
-			}
-		}
-
-		if ((previous)&&(previous->is_array())) {
-			for(unsigned long i=(unsigned long)arr.size();i<(unsigned long)previous->size();++i) {
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.V",OFFBASE_PATH_SEP,i);
-				unlink((path + tmp).c_str());
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.A",OFFBASE_PATH_SEP,i);
-				_rmDashRf(path + tmp);
-				snprintf(tmp,sizeof(tmp),"%s%.10lx.O",OFFBASE_PATH_SEP,i);
-				_rmDashRf(path + tmp);
-			}
-		}
-
-		return true;
-	}
-
-	static inline bool _commitObj(const std::string &path,const nlohmann::json &obj,const nlohmann::json *previous,std::vector<std::string> *errors)
-	{
-		if (!obj.is_object())
-			return false;
-
-		mkdir(path.c_str(),0755);
-
-		for(nlohmann::json::const_iterator i(obj.begin());i!=obj.end();++i) {
-			if (i.key().length() == 0)
-				continue;
-
-			const nlohmann::json *next = (const nlohmann::json *)0;
-			if ((previous)&&(previous->is_object())) {
-				nlohmann::json::const_iterator saved(previous->find(i.key()));
-				if (saved != previous->end()) {
-					next = &(saved.value());
-					if (i.value() == *next)
-						continue;
-				}
-			}
-
-			const std::string keyp(path + OFFBASE_PATH_SEP + escapeKey(i.key()));
-			if (i.value().is_object()) {
-				if (!_commitObj(keyp + ".O",i.value(),next,errors))
-					return false;
-				unlink((keyp + ".V").c_str());
-				_rmDashRf(keyp + ".A");
-			} else if (i.value().is_array()) {
-				if (!_commitArr(keyp + ".A",i.value(),next,errors))
-					return false;
-				unlink((keyp + ".V").c_str());
-				_rmDashRf(keyp + ".O");
-			} else {
-				FILE *f = fopen((keyp + ".V").c_str(),"w");
-				if (f) {
-					const std::string v(i.value().dump());
-					if (fwrite(v.c_str(),v.length(),1,f) != 1) {
-						fclose(f);
-						return false;
-					} else {
-						fclose(f);
-					}
-				} else {
-					return false;
-				}
-				_rmDashRf(keyp + ".A");
-				_rmDashRf(keyp + ".O");
-			}
-		}
-
-		if ((previous)&&(previous->is_object())) {
-			for(nlohmann::json::const_iterator i(previous->begin());i!=previous->end();++i) {
-				if ((i.key().length() > 0)&&(obj.find(i.key()) == obj.end())) {
-					const std::string keyp(path + OFFBASE_PATH_SEP + escapeKey(i.key()));
- 					unlink((keyp + ".V").c_str());
-					_rmDashRf(keyp + ".A");
-					_rmDashRf(keyp + ".O");
-				}
-			}
-		}
-
-		return true;
-	}
-
-	std::string _path;
-	nlohmann::json _saved;
-};
-
-#endif
diff --git a/make-mac.mk b/make-mac.mk
index e821c4cf..09e04eab 100644
--- a/make-mac.mk
+++ b/make-mac.mk
@@ -65,7 +65,7 @@ else
 	STRIP=strip
 endif
 
-CXXFLAGS=$(CFLAGS) -fno-rtti
+CXXFLAGS=$(CFLAGS) -fno-rtti -mmacosx-version-min=10.7 -std=c++11 -stdlib=libc++ 
 
 all: one
 
@@ -78,7 +78,7 @@ one:	$(OBJS) service/OneService.o one.o
 	$(CODESIGN) -vvv zerotier-one
 
 cli:	FORCE
-	$(CXX) -Os -mmacosx-version-min=10.7 -std=c++11 -stdlib=libc++ -o zerotier cli/zerotier.cpp osdep/OSUtils.cpp node/InetAddress.cpp node/Utils.cpp node/Salsa20.cpp node/Identity.cpp node/SHA512.cpp node/C25519.cpp -lcurl
+	$(CXX) $(CXXFLAGS) -o zerotier cli/zerotier.cpp osdep/OSUtils.cpp node/InetAddress.cpp node/Utils.cpp node/Salsa20.cpp node/Identity.cpp node/SHA512.cpp node/C25519.cpp -lcurl
 	$(STRIP) zerotier
 
 selftest: $(OBJS) selftest.o
diff --git a/node/InetAddress.cpp b/node/InetAddress.cpp
index 3f6b9be6..12446909 100644
--- a/node/InetAddress.cpp
+++ b/node/InetAddress.cpp
@@ -113,7 +113,7 @@ void InetAddress::set(const std::string &ip,unsigned int port)
 		sin6->sin6_port = Utils::hton((uint16_t)port);
 		if (inet_pton(AF_INET6,ip.c_str(),(void *)&(sin6->sin6_addr.s6_addr)) <= 0)
 			memset(this,0,sizeof(InetAddress));
-	} else {
+	} else if (ip.find('.') != std::string::npos) {
 		struct sockaddr_in *sin = reinterpret_cast<struct sockaddr_in *>(this);
 		ss_family = AF_INET;
 		sin->sin_port = Utils::hton((uint16_t)port);
diff --git a/osdep/OSUtils.cpp b/osdep/OSUtils.cpp
index 3a04308b..086bb269 100644
--- a/osdep/OSUtils.cpp
+++ b/osdep/OSUtils.cpp
@@ -107,6 +107,86 @@ std::vector<std::string> OSUtils::listDirectory(const char *path)
 	return r;
 }
 
+std::vector<std::string> OSUtils::listSubdirectories(const char *path)
+{
+	std::vector<std::string> r;
+
+#ifdef __WINDOWS__
+	HANDLE hFind;
+	WIN32_FIND_DATAA ffd;
+	if ((hFind = FindFirstFileA((std::string(path) + "\\*").c_str(),&ffd)) != INVALID_HANDLE_VALUE) {
+		do {
+			if ((strcmp(ffd.cFileName,"."))&&(strcmp(ffd.cFileName,".."))&&((ffd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0))
+				r.push_back(std::string(ffd.cFileName));
+		} while (FindNextFileA(hFind,&ffd));
+		FindClose(hFind);
+	}
+#else
+	struct dirent de;
+	struct dirent *dptr;
+	DIR *d = opendir(path);
+	if (!d)
+		return r;
+	dptr = (struct dirent *)0;
+	for(;;) {
+		if (readdir_r(d,&de,&dptr))
+			break;
+		if (dptr) {
+			if ((strcmp(dptr->d_name,"."))&&(strcmp(dptr->d_name,".."))&&(dptr->d_type == DT_DIR))
+				r.push_back(std::string(dptr->d_name));
+		} else break;
+	}
+	closedir(d);
+#endif
+
+	return r;
+}
+
+bool OSUtils::rmDashRf(const char *path)
+{
+#ifdef __WINDOWS__
+	HANDLE hFind;
+	WIN32_FIND_DATAA ffd;
+	if ((hFind = FindFirstFileA((std::string(path) + "\\*").c_str(),&ffd)) != INVALID_HANDLE_VALUE) {
+		do {
+			if ((strcmp(ffd.cFileName,".") != 0)&&(strcmp(ffd.cFileName,"..") != 0)) {
+				if ((ffd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0) {
+					if (DeleteFileA((std::string(path) + ZT_PATH_SEPARATOR_S + ffd.cFileName).c_str()) == FALSE)
+						return false;
+				} else {
+					if (!rmDashRf((std::string(path) + ZT_PATH_SEPARATOR_S + ffd.cFileName).c_str()))
+						return false;
+				}
+			}
+		} while (FindNextFileA(hFind,&ffd));
+		FindClose(hFind);
+	}
+	return (RemoveDirectoryA(path) != FALSE);
+#else
+	struct dirent de;
+	struct dirent *dptr;
+	DIR *d = opendir(path);
+	if (!d)
+		return true;
+	dptr = (struct dirent *)0;
+	for(;;) {
+		if (readdir_r(d,&de,&dptr))
+			break;
+		if ((dptr)&&(strcmp(dptr->d_name,".") != 0)&&(strcmp(dptr->d_name,"..") != 0)) {
+			std::string p(path);
+			p.push_back(ZT_PATH_SEPARATOR);
+			p.append(dptr->d_name);
+			if (unlink(p.c_str()) != 0) {
+				if (!rmDashRf(p.c_str()))
+					return false;
+			}
+		} else break;
+	}
+	closedir(d);
+	return (rmdir(path) == 0);
+#endif
+}
+
 void OSUtils::lockDownFile(const char *path,bool isDir)
 {
 #ifdef __UNIX_LIKE__
diff --git a/osdep/OSUtils.hpp b/osdep/OSUtils.hpp
index 25bed9fe..4f74344f 100644
--- a/osdep/OSUtils.hpp
+++ b/osdep/OSUtils.hpp
@@ -105,10 +105,26 @@ public:
 	 * This returns only files, not sub-directories.
 	 *
 	 * @param path Path to list
-	 * @return Names of files in directory
+	 * @return Names of files in directory (without path prepended)
 	 */
 	static std::vector<std::string> listDirectory(const char *path);
 
+	/**
+	 * List a directory's subdirectories
+	 *
+	 * @param path Path to list
+	 * @return Names of subdirectories (without path prepended)
+	 */
+	static std::vector<std::string> listSubdirectories(const char *path);
+
+	/**
+	 * Delete a directory and all its files and subdirectories recursively
+	 *
+	 * @param path Path to delete
+	 * @return True on success
+	 */
+	static bool rmDashRf(const char *path);
+
 	/**
 	 * Set modes on a file to something secure
 	 *
-- 
cgit v1.2.3


From 9892f7bb47768d613596b1051f9d0b9ddb849254 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Tue, 22 Nov 2016 11:06:58 -0800
Subject: Upgrade nlohmann::json

---
 ext/json/README.md |   51 +-
 ext/json/json.hpp  | 1309 +++++++++++++++++++++++++++++++++-------------------
 2 files changed, 873 insertions(+), 487 deletions(-)

(limited to 'ext/json/json.hpp')

diff --git a/ext/json/README.md b/ext/json/README.md
index c0bb61b1..4bcbe97f 100644
--- a/ext/json/README.md
+++ b/ext/json/README.md
@@ -1,24 +1,24 @@
 [![JSON for Modern C++](https://raw.githubusercontent.com/nlohmann/json/master/doc/json.gif)](https://github.com/nlohmann/json/releases)
 
 [![Build Status](https://travis-ci.org/nlohmann/json.svg?branch=master)](https://travis-ci.org/nlohmann/json)
-[![Build Status](https://ci.appveyor.com/api/projects/status/1acb366xfyg3qybk?svg=true)](https://ci.appveyor.com/project/nlohmann/json)
+[![Build Status](https://ci.appveyor.com/api/projects/status/1acb366xfyg3qybk/branch/develop?svg=true)](https://ci.appveyor.com/project/nlohmann/json)
 [![Coverage Status](https://img.shields.io/coveralls/nlohmann/json.svg)](https://coveralls.io/r/nlohmann/json)
-[![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
-[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/p5o4znPnGHJpDVqN)
+[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/fsf5FqYe6GoX68W6)
 [![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](http://nlohmann.github.io/json)
 [![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
 [![Github Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
 [![Github Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](http://github.com/nlohmann/json/issues)
+[![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/289/badge)](https://bestpractices.coreinfrastructure.org/projects/289)
 
 ## Design goals
 
 There are myriads of [JSON](http://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
 
-- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you know, what I mean.
+- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you'll know what I mean.
 
 - **Trivial integration**. Our whole code consists of a single header file [`json.hpp`](https://github.com/nlohmann/json/blob/develop/src/json.hpp). That's it. No library, no subproject, no dependencies, no complex build system. The class is written in vanilla C++11. All in all, everything should require no adjustment of your compiler flags or project settings.
 
-- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/blob/master/test/src/unit.cpp) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) that there are no memory leaks.
+- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/blob/master/test/src/unit.cpp) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) that there are no memory leaks. To maintain high quality, the project is following the [Core Infrastructure Initiative (CII) best practices](https://bestpractices.coreinfrastructure.org/projects/289).
 
 Other aspects were not so important to us:
 
@@ -283,8 +283,8 @@ json j_uset(c_uset); // only one entry for "one" is used
 // maybe ["two", "three", "four", "one"]
 
 std::multiset<std::string> c_mset {"one", "two", "one", "four"};
-json j_mset(c_mset); // only one entry for "one" is used
-// maybe ["one", "two", "four"]
+json j_mset(c_mset); // both entries for "one" are used
+// maybe ["one", "two", "one", "four"]
 
 std::unordered_multiset<std::string> c_umset {"one", "two", "one", "four"};
 json j_umset(c_umset); // both entries for "one" are used
@@ -416,7 +416,13 @@ The following compilers are currently used in continuous integration at [Travis]
 | GCC 4.9.3       | Ubuntu 14.04.4 LTS           | g++-4.9 (Ubuntu 4.9.3-8ubuntu2~14.04) 4.9.3 |
 | GCC 5.3.0       | Ubuntu 14.04.4 LTS           | g++-5 (Ubuntu 5.3.0-3ubuntu1~14.04) 5.3.0 20151204 |
 | GCC 6.1.1       | Ubuntu 14.04.4 LTS           | g++-6 (Ubuntu 6.1.1-3ubuntu11~14.04.1) 6.1.1 20160511 |
+| Clang 3.6.0     | Ubuntu 14.04.4 LTS           | clang version 3.6.0 (tags/RELEASE_360/final) |
+| Clang 3.6.1     | Ubuntu 14.04.4 LTS           | clang version 3.6.1 (tags/RELEASE_361/final) |
+| Clang 3.6.2     | Ubuntu 14.04.4 LTS           | clang version 3.6.2 (tags/RELEASE_362/final) |
+| Clang 3.7.0     | Ubuntu 14.04.4 LTS           | clang version 3.7.0 (tags/RELEASE_370/final) |
+| Clang 3.7.1     | Ubuntu 14.04.4 LTS           | clang version 3.7.1 (tags/RELEASE_371/final) |
 | Clang 3.8.0     | Ubuntu 14.04.4 LTS           | clang version 3.8.0 (tags/RELEASE_380/final) |
+| Clang 3.8.1     | Ubuntu 14.04.4 LTS           | clang version 3.8.1 (tags/RELEASE_381/final) |
 | Clang Xcode 6.1 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) |
 | Clang Xcode 6.2 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) |
 | Clang Xcode 6.3 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn) |
@@ -424,7 +430,7 @@ The following compilers are currently used in continuous integration at [Travis]
 | Clang Xcode 7.1 | Darwin Kernel Version 14.5.0 (OSX 10.10.5) | Apple LLVM version 7.0.0 (clang-700.1.76) |
 | Clang Xcode 7.2 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.0.2 (clang-700.1.81) |
 | Clang Xcode 7.3 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.3.0 (clang-703.0.29) |
-| Clang Xcode 8.0 | Darwin Kernel Version 15.5.0 (OSX 10.11.5) | Apple LLVM version 8.0.0 (clang-800.0.24.1) |
+| Clang Xcode 8.0 | Darwin Kernel Version 15.6.0 (OSX 10.11.6) | Apple LLVM version 8.0.0 (clang-800.0.38) |
 | Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25123.0 | 
 
 
@@ -486,14 +492,26 @@ I deeply appreciate the help of the following people.
 - [Mário Feroldi](https://github.com/thelostt) fixed a small typo.
 - [duncanwerner](https://github.com/duncanwerner) found a really embarrassing performance regression in the 2.0.0 release.
 - [Damien](https://github.com/dtoma) fixed one of the last conversion warnings.
+- [Thomas Braun](https://github.com/t-b) fixed a warning in a test case.
+- [Théo DELRIEU](https://github.com/theodelrieu) patiently and constructively oversaw the long way toward [iterator-range parsing](https://github.com/nlohmann/json/issues/290).
+- [Stefan](https://github.com/5tefan) fixed a minor issue in the documentation.
+- [Vasil Dimov](https://github.com/vasild) fixed the documentation regarding conversions from `std::multiset`.
+- [ChristophJud](https://github.com/ChristophJud) overworked the CMake files to ease project inclusion.
+- [Vladimir Petrigo](https://github.com/vpetrigo) made a SFINAE hack more readable.
+- [Denis Andrejew](https://github.com/seeekr) fixed a grammar issue in the README file.
 
 Thanks a lot for helping out!
 
 
 ## Notes
 
-- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](http://en.cppreference.com/w/cpp/error/assert).
+- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](http://en.cppreference.com/w/cpp/error/assert). In particular, note [`operator[]`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a2e26bd0b0168abb61f67ad5bcd5b9fa1.html#a2e26bd0b0168abb61f67ad5bcd5b9fa1) implements **unchecked access** for const objects: If the given key is not present, the behavior is undefined (think of a dereferenced null pointer) and yields an [assertion failure](https://github.com/nlohmann/json/issues/289) if assertions are switched on. If you are not sure whether an element in an object exists, use checked access with the [`at()` function](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a674de1ee73e6bf4843fc5dc1351fb726.html#a674de1ee73e6bf4843fc5dc1351fb726).
 - As the exact type of a number is not defined in the [JSON specification](http://rfc7159.net/rfc7159), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
+- The library supports **Unicode input** as follows:
+  - Only **UTF-8** encoded input is supported which is the default encoding for JSON according to [RFC 7159](http://rfc7159.net/rfc7159#rfc.section.8.1).
+  - Other encodings such as Latin-1, UTF-16, or UTF-32 are not supported and will yield parse errors.
+  - [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1) will not be replaced by the library.
+  - Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
 
 
 ## Execute unit tests
@@ -501,11 +519,20 @@ Thanks a lot for helping out!
 To compile and run the tests, you need to execute
 
 ```sh
-$ make
-$ ./json_unit "*"
+$ make check
 
 ===============================================================================
-All tests passed (8905012 assertions in 32 test cases)
+All tests passed (8905491 assertions in 36 test cases)
+```
+
+Alternatively, you can use [CMake](https://cmake.org) and run
+
+```sh
+$ mkdir build
+$ cd build
+$ cmake ..
+$ make
+$ ctest
 ```
 
 For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).
diff --git a/ext/json/json.hpp b/ext/json/json.hpp
index 878fb899..a302bb02 100644
--- a/ext/json/json.hpp
+++ b/ext/json/json.hpp
@@ -1,7 +1,7 @@
 /*
     __ _____ _____ _____
  __|  |   __|     |   | |  JSON for Modern C++
-|  |  |__   |  |  | | | |  version 2.0.2
+|  |  |__   |  |  | | | |  version 2.0.7
 |_____|_____|_____|_|___|  https://github.com/nlohmann/json
 
 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
@@ -29,30 +29,32 @@ SOFTWARE.
 #ifndef NLOHMANN_JSON_HPP
 #define NLOHMANN_JSON_HPP
 
-#include <algorithm>
-#include <array>
-#include <cassert>
-#include <ciso646>
-#include <cmath>
-#include <cstddef>
-#include <cstdint>
-#include <cstdlib>
-#include <functional>
-#include <initializer_list>
-#include <iomanip>
-#include <iostream>
-#include <iterator>
-#include <limits>
-#include <locale>
-#include <map>
-#include <memory>
-#include <numeric>
-#include <sstream>
-#include <stdexcept>
-#include <string>
-#include <type_traits>
-#include <utility>
-#include <vector>
+#include <algorithm> // all_of, for_each, transform
+#include <array> // array
+#include <cassert> // assert
+#include <cctype> // isdigit
+#include <ciso646> // and, not, or
+#include <cmath> // isfinite, signbit
+#include <cstddef> // nullptr_t, ptrdiff_t, size_t
+#include <cstdint> // int64_t, uint64_t
+#include <cstdlib> // strtod, strtof, strtold, strtoul
+#include <cstring> // strlen
+#include <functional> // function, hash, less
+#include <initializer_list> // initializer_list
+#include <iomanip> // setw
+#include <iostream> // istream, ostream
+#include <iterator> // advance, begin, bidirectional_iterator_tag, distance, end, inserter, iterator, iterator_traits, next, random_access_iterator_tag, reverse_iterator
+#include <limits> // numeric_limits
+#include <locale> // locale, numpunct
+#include <map> // map
+#include <memory> // addressof, allocator, allocator_traits, unique_ptr
+#include <numeric> // accumulate
+#include <sstream> // stringstream
+#include <stdexcept> // domain_error, invalid_argument, out_of_range
+#include <string> // getline, stoi, string, to_string
+#include <type_traits> // add_pointer, enable_if, is_arithmetic, is_base_of, is_const, is_constructible, is_convertible, is_floating_point, is_integral, is_nothrow_move_assignable, std::is_nothrow_move_constructible, std::is_pointer, std::is_reference, std::is_same, remove_const, remove_pointer, remove_reference
+#include <utility> // declval, forward, make_pair, move, pair, swap
+#include <vector> // vector
 
 // exclude unsupported compilers
 #if defined(__clang__)
@@ -73,6 +75,15 @@ SOFTWARE.
     #pragma GCC diagnostic ignored "-Wfloat-equal"
 #endif
 
+// allow for portable deprecation warnings
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #define JSON_DEPRECATED __attribute__((deprecated))
+#elif defined(_MSC_VER)
+    #define JSON_DEPRECATED __declspec(deprecated)
+#else
+    #define JSON_DEPRECATED
+#endif
+
 /*!
 @brief namespace for Niels Lohmann
 @see https://github.com/nlohmann
@@ -96,16 +107,19 @@ such as sequence containers. For instance, `std::map` passes the test as it
 contains a `mapped_type`, whereas `std::vector` fails the test.
 
 @sa http://stackoverflow.com/a/7728728/266378
-@since version 1.0.0
+@since version 1.0.0, overworked in version 2.0.6
 */
 template<typename T>
 struct has_mapped_type
 {
   private:
-    template<typename C> static char test(typename C::mapped_type*);
-    template<typename C> static char (&test(...))[2];
+    template <typename U, typename = typename U::mapped_type>
+    static int detect(U&&);
+
+    static void detect(...);
   public:
-    static constexpr bool value = sizeof(test<T>(0)) == 1;
+    static constexpr bool value =
+        std::is_integral<decltype(detect(std::declval<T>()))>::value;
 };
 
 /*!
@@ -950,7 +964,7 @@ class basic_json
 
     With a parser callback function, the result of parsing a JSON text can be
     influenced. When passed to @ref parse(std::istream&, const
-    parser_callback_t) or @ref parse(const string_t&, const parser_callback_t),
+    parser_callback_t) or @ref parse(const char*, const parser_callback_t),
     it is called on certain events (passed as @ref parse_event_t via parameter
     @a event) with a set recursion depth @a depth and context JSON value
     @a parsed. The return value of the callback function is a boolean
@@ -993,7 +1007,7 @@ class basic_json
     skipped completely or replaced by an empty discarded object.
 
     @sa @ref parse(std::istream&, parser_callback_t) or
-    @ref parse(const string_t&, parser_callback_t) for examples
+    @ref parse(const char*, parser_callback_t) for examples
 
     @since version 1.0.0
     */
@@ -1057,40 +1071,10 @@ class basic_json
     }
 
     /*!
-    @brief create a null object (implicitly)
-
-    Create a `null` JSON value. This is the implicit version of the `null`
-    value constructor as it takes no parameters.
-
-    @note The class invariant is satisfied, because it poses no requirements
-    for null values.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this constructor never throws
-    exceptions.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - As postcondition, it holds: `basic_json().empty() == true`.
-
-    @liveexample{The following code shows the constructor for a `null` JSON
-    value.,basic_json}
-
-    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
-
-    @since version 1.0.0
-    */
-    basic_json() = default;
-
-    /*!
-    @brief create a null object (explicitly)
+    @brief create a null object
 
-    Create a `null` JSON value. This is the explicitly version of the `null`
-    value constructor as it takes a null pointer as parameter. It allows to
-    create `null` values by explicitly assigning a `nullptr` to a JSON value.
+    Create a `null` JSON value. It either takes a null pointer as parameter
+    (explicitly creating `null`) or no parameter (implicitly creating `null`).
     The passed null pointer itself is not read -- it is only used to choose
     the right constructor.
 
@@ -1099,15 +1083,12 @@ class basic_json
     @exceptionsafety No-throw guarantee: this constructor never throws
     exceptions.
 
-    @liveexample{The following code shows the constructor with null pointer
-    parameter.,basic_json__nullptr_t}
-
-    @sa @ref basic_json() -- default constructor (implicitly creating a `null`
-    value)
+    @liveexample{The following code shows the constructor with and without a
+    null pointer parameter.,basic_json__nullptr_t}
 
     @since version 1.0.0
     */
-    basic_json(std::nullptr_t) noexcept
+    basic_json(std::nullptr_t = nullptr) noexcept
         : basic_json(value_t::null)
     {
         assert_invariant();
@@ -1164,11 +1145,9 @@ class basic_json
 
     @since version 1.0.0
     */
-    template <class CompatibleObjectType, typename
-              std::enable_if<
-                  std::is_constructible<typename object_t::key_type, typename CompatibleObjectType::key_type>::value and
-                  std::is_constructible<basic_json, typename CompatibleObjectType::mapped_type>::value, int>::type
-              = 0>
+    template<class CompatibleObjectType, typename std::enable_if<
+                 std::is_constructible<typename object_t::key_type, typename CompatibleObjectType::key_type>::value and
+                 std::is_constructible<basic_json, typename CompatibleObjectType::mapped_type>::value, int>::type = 0>
     basic_json(const CompatibleObjectType& val)
         : m_type(value_t::object)
     {
@@ -1229,16 +1208,14 @@ class basic_json
 
     @since version 1.0.0
     */
-    template <class CompatibleArrayType, typename
-              std::enable_if<
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::reverse_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename basic_json_t::const_reverse_iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename array_t::iterator>::value and
-                  not std::is_same<CompatibleArrayType, typename array_t::const_iterator>::value and
-                  std::is_constructible<basic_json, typename CompatibleArrayType::value_type>::value, int>::type
-              = 0>
+    template<class CompatibleArrayType, typename std::enable_if<
+                 not std::is_same<CompatibleArrayType, typename basic_json_t::iterator>::value and
+                 not std::is_same<CompatibleArrayType, typename basic_json_t::const_iterator>::value and
+                 not std::is_same<CompatibleArrayType, typename basic_json_t::reverse_iterator>::value and
+                 not std::is_same<CompatibleArrayType, typename basic_json_t::const_reverse_iterator>::value and
+                 not std::is_same<CompatibleArrayType, typename array_t::iterator>::value and
+                 not std::is_same<CompatibleArrayType, typename array_t::const_iterator>::value and
+                 std::is_constructible<basic_json, typename CompatibleArrayType::value_type>::value, int>::type = 0>
     basic_json(const CompatibleArrayType& val)
         : m_type(value_t::array)
     {
@@ -1324,10 +1301,8 @@ class basic_json
 
     @since version 1.0.0
     */
-    template <class CompatibleStringType, typename
-              std::enable_if<
-                  std::is_constructible<string_t, CompatibleStringType>::value, int>::type
-              = 0>
+    template<class CompatibleStringType, typename std::enable_if<
+                 std::is_constructible<string_t, CompatibleStringType>::value, int>::type = 0>
     basic_json(const CompatibleStringType& val)
         : basic_json(string_t(val))
     {
@@ -1377,12 +1352,9 @@ class basic_json
 
     @since version 1.0.0
     */
-    template<typename T,
-             typename std::enable_if<
-                 not (std::is_same<T, int>::value)
-                 and std::is_same<T, number_integer_t>::value
-                 , int>::type
-             = 0>
+    template<typename T, typename std::enable_if<
+                 not (std::is_same<T, int>::value) and
+                 std::is_same<T, number_integer_t>::value, int>::type = 0>
     basic_json(const number_integer_t val) noexcept
         : m_type(value_t::number_integer), m_value(val)
     {
@@ -1446,13 +1418,11 @@ class basic_json
 
     @since version 1.0.0
     */
-    template<typename CompatibleNumberIntegerType, typename
-             std::enable_if<
+    template<typename CompatibleNumberIntegerType, typename std::enable_if<
                  std::is_constructible<number_integer_t, CompatibleNumberIntegerType>::value and
                  std::numeric_limits<CompatibleNumberIntegerType>::is_integer and
                  std::numeric_limits<CompatibleNumberIntegerType>::is_signed,
-                 CompatibleNumberIntegerType>::type
-             = 0>
+                 CompatibleNumberIntegerType>::type = 0>
     basic_json(const CompatibleNumberIntegerType val) noexcept
         : m_type(value_t::number_integer),
           m_value(static_cast<number_integer_t>(val))
@@ -1477,12 +1447,9 @@ class basic_json
 
     @since version 2.0.0
     */
-    template<typename T,
-             typename std::enable_if<
-                 not (std::is_same<T, int>::value)
-                 and std::is_same<T, number_unsigned_t>::value
-                 , int>::type
-             = 0>
+    template<typename T, typename std::enable_if<
+                 not (std::is_same<T, int>::value) and
+                 std::is_same<T, number_unsigned_t>::value, int>::type = 0>
     basic_json(const number_unsigned_t val) noexcept
         : m_type(value_t::number_unsigned), m_value(val)
     {
@@ -1509,13 +1476,11 @@ class basic_json
 
     @since version 2.0.0
     */
-    template <typename CompatibleNumberUnsignedType, typename
-              std::enable_if <
-                  std::is_constructible<number_unsigned_t, CompatibleNumberUnsignedType>::value and
-                  std::numeric_limits<CompatibleNumberUnsignedType>::is_integer and
-                  not std::numeric_limits<CompatibleNumberUnsignedType>::is_signed,
-                  CompatibleNumberUnsignedType>::type
-              = 0>
+    template<typename CompatibleNumberUnsignedType, typename std::enable_if <
+                 std::is_constructible<number_unsigned_t, CompatibleNumberUnsignedType>::value and
+                 std::numeric_limits<CompatibleNumberUnsignedType>::is_integer and
+                 not std::numeric_limits<CompatibleNumberUnsignedType>::is_signed,
+                 CompatibleNumberUnsignedType>::type = 0>
     basic_json(const CompatibleNumberUnsignedType val) noexcept
         : m_type(value_t::number_unsigned),
           m_value(static_cast<number_unsigned_t>(val))
@@ -1591,11 +1556,9 @@ class basic_json
 
     @since version 1.0.0
     */
-    template<typename CompatibleNumberFloatType, typename = typename
-             std::enable_if<
+    template<typename CompatibleNumberFloatType, typename = typename std::enable_if<
                  std::is_constructible<number_float_t, CompatibleNumberFloatType>::value and
-                 std::is_floating_point<CompatibleNumberFloatType>::value>::type
-             >
+                 std::is_floating_point<CompatibleNumberFloatType>::value>::type>
     basic_json(const CompatibleNumberFloatType val) noexcept
         : basic_json(number_float_t(val))
     {
@@ -1843,7 +1806,8 @@ class basic_json
     @param[in] first begin of the range to copy from (included)
     @param[in] last end of the range to copy from (excluded)
 
-    @pre Iterators @a first and @a last must be initialized.
+    @pre Iterators @a first and @a last must be initialized. **This
+         precondition is enforced with an assertion.**
 
     @throw std::domain_error if iterators are not compatible; that is, do not
     belong to the same JSON value; example: `"iterators are not compatible"`
@@ -1861,12 +1825,9 @@ class basic_json
 
     @since version 1.0.0
     */
-    template <class InputIT, typename
-              std::enable_if<
-                  std::is_same<InputIT, typename basic_json_t::iterator>::value or
-                  std::is_same<InputIT, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
+    template<class InputIT, typename std::enable_if<
+                 std::is_same<InputIT, typename basic_json_t::iterator>::value or
+                 std::is_same<InputIT, typename basic_json_t::const_iterator>::value, int>::type = 0>
     basic_json(InputIT first, InputIT last)
     {
         assert(first.m_object != nullptr);
@@ -1970,12 +1931,21 @@ class basic_json
 
     @note A UTF-8 byte order mark is silently ignored.
 
+    @deprecated This constructor is deprecated and will be removed in version
+      3.0.0 to unify the interface of the library. Deserialization will be
+      done by stream operators or by calling one of the `parse` functions,
+      e.g. @ref parse(std::istream&, const parser_callback_t). That is, calls
+      like `json j(i);` for an input stream @a i need to be replaced by
+      `json j = json::parse(i);`. See the example below.
+
     @liveexample{The example below demonstrates constructing a JSON value from
     a `std::stringstream` with and without callback
     function.,basic_json__istream}
 
-    @since version 2.0.0
+    @since version 2.0.0, deprecated in version 2.0.3, to be removed in
+           version 3.0.0
     */
+    JSON_DEPRECATED
     explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)
     {
         *this = parser(i, cb).parse();
@@ -2231,7 +2201,8 @@ class basic_json
     {
         std::stringstream ss;
         // fix locale problems
-        ss.imbue(std::locale(std::locale(), new DecimalSeparator));
+        const static std::locale loc(std::locale(), new DecimalSeparator);
+        ss.imbue(loc);
 
         // 6, 15 or 16 digits of precision allows round-trip IEEE 754
         // string->float->string, string->double->string or string->long
@@ -2614,11 +2585,9 @@ class basic_json
     //////////////////
 
     /// get an object (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<typename object_t::key_type, typename T::key_type>::value and
-                  std::is_convertible<basic_json_t, typename T::mapped_type>::value
-                  , int>::type = 0>
+    template<class T, typename std::enable_if<
+                 std::is_convertible<typename object_t::key_type, typename T::key_type>::value and
+                 std::is_convertible<basic_json_t, typename T::mapped_type>::value, int>::type = 0>
     T get_impl(T*) const
     {
         if (is_object())
@@ -2645,14 +2614,12 @@ class basic_json
     }
 
     /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, typename T::value_type>::value and
-                  not std::is_same<basic_json_t, typename T::value_type>::value and
-                  not std::is_arithmetic<T>::value and
-                  not std::is_convertible<std::string, T>::value and
-                  not has_mapped_type<T>::value
-                  , int>::type = 0>
+    template<class T, typename std::enable_if<
+                 std::is_convertible<basic_json_t, typename T::value_type>::value and
+                 not std::is_same<basic_json_t, typename T::value_type>::value and
+                 not std::is_arithmetic<T>::value and
+                 not std::is_convertible<std::string, T>::value and
+                 not has_mapped_type<T>::value, int>::type = 0>
     T get_impl(T*) const
     {
         if (is_array())
@@ -2672,11 +2639,9 @@ class basic_json
     }
 
     /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, T>::value and
-                  not std::is_same<basic_json_t, T>::value
-                  , int>::type = 0>
+    template<class T, typename std::enable_if<
+                 std::is_convertible<basic_json_t, T>::value and
+                 not std::is_same<basic_json_t, T>::value, int>::type = 0>
     std::vector<T> get_impl(std::vector<T>*) const
     {
         if (is_array())
@@ -2697,11 +2662,9 @@ class basic_json
     }
 
     /// get an array (explicit)
-    template <class T, typename
-              std::enable_if<
-                  std::is_same<basic_json, typename T::value_type>::value and
-                  not has_mapped_type<T>::value
-                  , int>::type = 0>
+    template<class T, typename std::enable_if<
+                 std::is_same<basic_json, typename T::value_type>::value and
+                 not has_mapped_type<T>::value, int>::type = 0>
     T get_impl(T*) const
     {
         if (is_array())
@@ -2728,10 +2691,8 @@ class basic_json
     }
 
     /// get a string (explicit)
-    template <typename T, typename
-              std::enable_if<
-                  std::is_convertible<string_t, T>::value
-                  , int>::type = 0>
+    template<typename T, typename std::enable_if<
+                 std::is_convertible<string_t, T>::value, int>::type = 0>
     T get_impl(T*) const
     {
         if (is_string())
@@ -2745,10 +2706,8 @@ class basic_json
     }
 
     /// get a number (explicit)
-    template<typename T, typename
-             std::enable_if<
-                 std::is_arithmetic<T>::value
-                 , int>::type = 0>
+    template<typename T, typename std::enable_if<
+                 std::is_arithmetic<T>::value, int>::type = 0>
     T get_impl(T*) const
     {
         switch (m_type)
@@ -2937,10 +2896,8 @@ class basic_json
 
     @since version 1.0.0
     */
-    template<typename ValueType, typename
-             std::enable_if<
-                 not std::is_pointer<ValueType>::value
-                 , int>::type = 0>
+    template<typename ValueType, typename std::enable_if<
+                 not std::is_pointer<ValueType>::value, int>::type = 0>
     ValueType get() const
     {
         return get_impl(static_cast<ValueType*>(nullptr));
@@ -2973,10 +2930,8 @@ class basic_json
 
     @since version 1.0.0
     */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value, int>::type = 0>
     PointerType get() noexcept
     {
         // delegate the call to get_ptr
@@ -2987,10 +2942,8 @@ class basic_json
     @brief get a pointer value (explicit)
     @copydoc get()
     */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value, int>::type = 0>
     constexpr const PointerType get() const noexcept
     {
         // delegate the call to get_ptr
@@ -3023,10 +2976,8 @@ class basic_json
 
     @since version 1.0.0
     */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 , int>::type = 0>
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value, int>::type = 0>
     PointerType get_ptr() noexcept
     {
         // get the type of the PointerType (remove pointer and const)
@@ -3052,11 +3003,9 @@ class basic_json
     @brief get a pointer value (implicit)
     @copydoc get_ptr()
     */
-    template<typename PointerType, typename
-             std::enable_if<
-                 std::is_pointer<PointerType>::value
-                 and std::is_const<typename std::remove_pointer<PointerType>::type>::value
-                 , int>::type = 0>
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value and
+                 std::is_const<typename std::remove_pointer<PointerType>::type>::value, int>::type = 0>
     constexpr const PointerType get_ptr() const noexcept
     {
         // get the type of the PointerType (remove pointer and const)
@@ -3104,10 +3053,8 @@ class basic_json
 
     @since version 1.1.0
     */
-    template<typename ReferenceType, typename
-             std::enable_if<
-                 std::is_reference<ReferenceType>::value
-                 , int>::type = 0>
+    template<typename ReferenceType, typename std::enable_if<
+                 std::is_reference<ReferenceType>::value, int>::type = 0>
     ReferenceType get_ref()
     {
         // delegate call to get_ref_impl
@@ -3118,11 +3065,9 @@ class basic_json
     @brief get a reference value (implicit)
     @copydoc get_ref()
     */
-    template<typename ReferenceType, typename
-             std::enable_if<
-                 std::is_reference<ReferenceType>::value
-                 and std::is_const<typename std::remove_reference<ReferenceType>::type>::value
-                 , int>::type = 0>
+    template<typename ReferenceType, typename std::enable_if<
+                 std::is_reference<ReferenceType>::value and
+                 std::is_const<typename std::remove_reference<ReferenceType>::type>::value, int>::type = 0>
     ReferenceType get_ref() const
     {
         // delegate call to get_ref_impl
@@ -3157,10 +3102,9 @@ class basic_json
 
     @since version 1.0.0
     */
-    template < typename ValueType, typename
-               std::enable_if <
-                   not std::is_pointer<ValueType>::value
-                   and not std::is_same<ValueType, typename string_t::value_type>::value
+    template < typename ValueType, typename std::enable_if <
+                   not std::is_pointer<ValueType>::value and
+                   not std::is_same<ValueType, typename string_t::value_type>::value
 #ifndef _MSC_VER  // Fix for issue #167 operator<< abiguity under VS2015
                    and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
 #endif
@@ -3509,6 +3453,9 @@ class basic_json
 
     @return const reference to the element at key @a key
 
+    @pre The element with key @a key must exist. **This precondition is
+         enforced with an assertion.**
+
     @throw std::domain_error if JSON is not an object; example: `"cannot use
     operator[] with null"`
 
@@ -3667,6 +3614,9 @@ class basic_json
 
     @return const reference to the element at key @a key
 
+    @pre The element with key @a key must exist. **This precondition is
+         enforced with an assertion.**
+
     @throw std::domain_error if JSON is not an object; example: `"cannot use
     operator[] with null"`
 
@@ -3744,10 +3694,8 @@ class basic_json
 
     @since version 1.0.0
     */
-    template <class ValueType, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, ValueType>::value
-                  , int>::type = 0>
+    template<class ValueType, typename std::enable_if<
+                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
     ValueType value(const typename object_t::key_type& key, ValueType default_value) const
     {
         // at only works for objects
@@ -3820,10 +3768,8 @@ class basic_json
 
     @since version 2.0.2
     */
-    template <class ValueType, typename
-              std::enable_if<
-                  std::is_convertible<basic_json_t, ValueType>::value
-                  , int>::type = 0>
+    template<class ValueType, typename std::enable_if<
+                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
     ValueType value(const json_pointer& ptr, ValueType default_value) const
     {
         // at only works for objects
@@ -3867,7 +3813,8 @@ class basic_json
     @complexity Constant.
 
     @pre The JSON value must not be `null` (would throw `std::out_of_range`)
-    or an empty array or object (undefined behavior, guarded by assertions).
+    or an empty array or object (undefined behavior, **guarded by
+    assertions**).
     @post The JSON value remains unchanged.
 
     @throw std::out_of_range when called on `null` value
@@ -3909,7 +3856,8 @@ class basic_json
     @complexity Constant.
 
     @pre The JSON value must not be `null` (would throw `std::out_of_range`)
-    or an empty array or object (undefined behavior, guarded by assertions).
+    or an empty array or object (undefined behavior, **guarded by
+    assertions**).
     @post The JSON value remains unchanged.
 
     @throw std::out_of_range when called on `null` value.
@@ -3951,7 +3899,7 @@ class basic_json
     @return Iterator following the last removed element. If the iterator @a
     pos refers to the last element, the `end()` iterator is returned.
 
-    @tparam InteratorType an @ref iterator or @ref const_iterator
+    @tparam IteratorType an @ref iterator or @ref const_iterator
 
     @post Invalidates iterators and references at or after the point of the
     erase, including the `end()` iterator.
@@ -3973,7 +3921,7 @@ class basic_json
     @liveexample{The example shows the result of `erase()` for different JSON
     types.,erase__IteratorType}
 
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
     the given range
     @sa @ref erase(const typename object_t::key_type&) -- removes the element
     from an object at the given key
@@ -3982,13 +3930,11 @@ class basic_json
 
     @since version 1.0.0
     */
-    template <class InteratorType, typename
-              std::enable_if<
-                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
-                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
-    InteratorType erase(InteratorType pos)
+    template<class IteratorType, typename std::enable_if<
+                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
+                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
+             = 0>
+    IteratorType erase(IteratorType pos)
     {
         // make sure iterator fits the current value
         if (this != pos.m_object)
@@ -3996,7 +3942,7 @@ class basic_json
             throw std::domain_error("iterator does not fit current value");
         }
 
-        InteratorType result = end();
+        IteratorType result = end();
 
         switch (m_type)
         {
@@ -4060,7 +4006,7 @@ class basic_json
     @return Iterator following the last removed element. If the iterator @a
     second refers to the last element, the `end()` iterator is returned.
 
-    @tparam InteratorType an @ref iterator or @ref const_iterator
+    @tparam IteratorType an @ref iterator or @ref const_iterator
 
     @post Invalidates iterators and references at or after the point of the
     erase, including the `end()` iterator.
@@ -4083,7 +4029,7 @@ class basic_json
     @liveexample{The example shows the result of `erase()` for different JSON
     types.,erase__IteratorType_IteratorType}
 
-    @sa @ref erase(InteratorType) -- removes the element at a given position
+    @sa @ref erase(IteratorType) -- removes the element at a given position
     @sa @ref erase(const typename object_t::key_type&) -- removes the element
     from an object at the given key
     @sa @ref erase(const size_type) -- removes the element from an array at
@@ -4091,13 +4037,11 @@ class basic_json
 
     @since version 1.0.0
     */
-    template <class InteratorType, typename
-              std::enable_if<
-                  std::is_same<InteratorType, typename basic_json_t::iterator>::value or
-                  std::is_same<InteratorType, typename basic_json_t::const_iterator>::value
-                  , int>::type
-              = 0>
-    InteratorType erase(InteratorType first, InteratorType last)
+    template<class IteratorType, typename std::enable_if<
+                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
+                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
+             = 0>
+    IteratorType erase(IteratorType first, IteratorType last)
     {
         // make sure iterator fits the current value
         if (this != first.m_object or this != last.m_object)
@@ -4105,7 +4049,7 @@ class basic_json
             throw std::domain_error("iterators do not fit current value");
         }
 
-        InteratorType result = end();
+        IteratorType result = end();
 
         switch (m_type)
         {
@@ -4177,8 +4121,8 @@ class basic_json
 
     @liveexample{The example shows the effect of `erase()`.,erase__key_type}
 
-    @sa @ref erase(InteratorType) -- removes the element at a given position
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    @sa @ref erase(IteratorType) -- removes the element at a given position
+    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
     the given range
     @sa @ref erase(const size_type) -- removes the element from an array at
     the given index
@@ -4214,8 +4158,8 @@ class basic_json
 
     @liveexample{The example shows the effect of `erase()`.,erase__size_type}
 
-    @sa @ref erase(InteratorType) -- removes the element at a given position
-    @sa @ref erase(InteratorType, InteratorType) -- removes the elements in
+    @sa @ref erase(IteratorType) -- removes the element at a given position
+    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
     the given range
     @sa @ref erase(const typename object_t::key_type&) -- removes the element
     from an object at the given key
@@ -5923,9 +5867,45 @@ class basic_json
     /// @{
 
     /*!
-    @brief deserialize from string
+    @brief deserialize from an array
+
+    This function reads from an array of 1-byte values.
 
-    @param[in] s  string to read a serialized JSON value from
+    @pre Each element of the container has a size of 1 byte. Violating this
+    precondition yields undefined behavior. **This precondition is enforced
+    with a static assertion.**
+
+    @param[in] array  array to read from
+    @param[in] cb  a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @return result of the deserialization
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates the `parse()` function reading
+    from an array.,parse__array__parser_callback_t}
+
+    @since version 2.0.3
+    */
+    template<class T, std::size_t N>
+    static basic_json parse(T (&array)[N],
+                            const parser_callback_t cb = nullptr)
+    {
+        // delegate the call to the iterator-range parse overload
+        return parse(std::begin(array), std::end(array), cb);
+    }
+
+    /*!
+    @brief deserialize from string literal
+
+    @tparam CharT character/literal type with size of 1 byte
+    @param[in] s  string literal to read a serialized JSON value from
     @param[in] cb a parser callback function of type @ref parser_callback_t
     which is used to control the deserialization by filtering unwanted values
     (optional)
@@ -5937,6 +5917,8 @@ class basic_json
     @a cb has a super-linear complexity.
 
     @note A UTF-8 byte order mark is silently ignored.
+    @note String containers like `std::string` or @ref string_t can be parsed
+          with @ref parse(const ContiguousContainer&, const parser_callback_t)
 
     @liveexample{The example below demonstrates the `parse()` function with
     and without callback function.,parse__string__parser_callback_t}
@@ -5944,12 +5926,16 @@ class basic_json
     @sa @ref parse(std::istream&, const parser_callback_t) for a version that
     reads from an input stream
 
-    @since version 1.0.0
+    @since version 1.0.0 (originally for @ref string_t)
     */
-    static basic_json parse(const string_t& s,
+    template<typename CharPT, typename std::enable_if<
+                 std::is_pointer<CharPT>::value and
+                 std::is_integral<typename std::remove_pointer<CharPT>::type>::value and
+                 sizeof(typename std::remove_pointer<CharPT>::type) == 1, int>::type = 0>
+    static basic_json parse(const CharPT s,
                             const parser_callback_t cb = nullptr)
     {
-        return parser(s, cb).parse();
+        return parser(reinterpret_cast<const char*>(s), cb).parse();
     }
 
     /*!
@@ -5971,7 +5957,7 @@ class basic_json
     @liveexample{The example below demonstrates the `parse()` function with
     and without callback function.,parse__istream__parser_callback_t}
 
-    @sa @ref parse(const string_t&, const parser_callback_t) for a version
+    @sa @ref parse(const char*, const parser_callback_t) for a version
     that reads from a string
 
     @since version 1.0.0
@@ -5991,6 +5977,130 @@ class basic_json
         return parser(i, cb).parse();
     }
 
+    /*!
+    @brief deserialize from an iterator range with contiguous storage
+
+    This function reads from an iterator range of a container with contiguous
+    storage of 1-byte values. Compatible container types include
+    `std::vector`, `std::string`, `std::array`, `std::valarray`, and
+    `std::initializer_list`. Furthermore, C-style arrays can be used with
+    `std::begin()`/`std::end()`. User-defined containers can be used as long
+    as they implement random-access iterators and a contiguous storage.
+
+    @pre The iterator range is contiguous. Violating this precondition yields
+    undefined behavior. **This precondition is enforced with an assertion.**
+    @pre Each element in the range has a size of 1 byte. Violating this
+    precondition yields undefined behavior. **This precondition is enforced
+    with a static assertion.**
+
+    @warning There is no way to enforce all preconditions at compile-time. If
+             the function is called with noncompliant iterators and with
+             assertions switched off, the behavior is undefined and will most
+             likely yield segmentation violation.
+
+    @tparam IteratorType iterator of container with contiguous storage
+    @param[in] first  begin of the range to parse (included)
+    @param[in] last  end of the range to parse (excluded)
+    @param[in] cb  a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @return result of the deserialization
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates the `parse()` function reading
+    from an iterator range.,parse__iteratortype__parser_callback_t}
+
+    @since version 2.0.3
+    */
+    template<class IteratorType, typename std::enable_if<
+                 std::is_base_of<
+                     std::random_access_iterator_tag,
+                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
+    static basic_json parse(IteratorType first, IteratorType last,
+                            const parser_callback_t cb = nullptr)
+    {
+        // assertion to check that the iterator range is indeed contiguous,
+        // see http://stackoverflow.com/a/35008842/266378 for more discussion
+        assert(std::accumulate(first, last, std::make_pair<bool, int>(true, 0),
+                               [&first](std::pair<bool, int> res, decltype(*first) val)
+        {
+            res.first &= (val == *(std::next(std::addressof(*first), res.second++)));
+            return res;
+        }).first);
+
+        // assertion to check that each element is 1 byte long
+        static_assert(sizeof(typename std::iterator_traits<IteratorType>::value_type) == 1,
+                      "each element in the iterator range must have the size of 1 byte");
+
+        // if iterator range is empty, create a parser with an empty string
+        // to generate "unexpected EOF" error message
+        if (std::distance(first, last) <= 0)
+        {
+            return parser("").parse();
+        }
+
+        return parser(first, last, cb).parse();
+    }
+
+    /*!
+    @brief deserialize from a container with contiguous storage
+
+    This function reads from a container with contiguous storage of 1-byte
+    values. Compatible container types include `std::vector`, `std::string`,
+    `std::array`, and `std::initializer_list`. User-defined containers can be
+    used as long as they implement random-access iterators and a contiguous
+    storage.
+
+    @pre The container storage is contiguous. Violating this precondition
+    yields undefined behavior. **This precondition is enforced with an
+    assertion.**
+    @pre Each element of the container has a size of 1 byte. Violating this
+    precondition yields undefined behavior. **This precondition is enforced
+    with a static assertion.**
+
+    @warning There is no way to enforce all preconditions at compile-time. If
+             the function is called with a noncompliant container and with
+             assertions switched off, the behavior is undefined and will most
+             likely yield segmentation violation.
+
+    @tparam ContiguousContainer container type with contiguous storage
+    @param[in] c  container to read from
+    @param[in] cb  a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+
+    @return result of the deserialization
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates the `parse()` function reading
+    from a contiguous container.,parse__contiguouscontainer__parser_callback_t}
+
+    @since version 2.0.3
+    */
+    template<class ContiguousContainer, typename std::enable_if<
+                 not std::is_pointer<ContiguousContainer>::value and
+                 std::is_base_of<
+                     std::random_access_iterator_tag,
+                     typename std::iterator_traits<decltype(std::begin(std::declval<ContiguousContainer const>()))>::iterator_category>::value
+                 , int>::type = 0>
+    static basic_json parse(const ContiguousContainer& c,
+                            const parser_callback_t cb = nullptr)
+    {
+        // delegate the call to the iterator-range parse overload
+        return parse(std::begin(c), std::end(c), cb);
+    }
+
     /*!
     @brief deserialize from stream
 
@@ -6044,7 +6154,7 @@ class basic_json
     Returns the type name as string to be used in error messages - usually to
     indicate that a function was called on a wrong JSON type.
 
-    @return basically a string representation of a the @ref m_type member
+    @return basically a string representation of a the @a m_type member
 
     @complexity Constant.
 
@@ -6592,8 +6702,8 @@ class basic_json
     @note An iterator is called *initialized* when a pointer to a JSON value
           has been set (e.g., by a constructor or a copy assignment). If the
           iterator is default-constructed, it is *uninitialized* and most
-          methods are undefined. The library uses assertions to detect calls
-          on uninitialized iterators.
+          methods are undefined. **The library uses assertions to detect calls
+          on uninitialized iterators.**
 
     @requirement The class satisfies the following concept requirements:
     - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
@@ -7495,32 +7605,33 @@ class basic_json
         /// the char type to use in the lexer
         using lexer_char_t = unsigned char;
 
-        /// constructor with a given buffer
-        explicit lexer(const string_t& s) noexcept
-            : m_stream(nullptr), m_buffer(s)
+        /// a lexer from a buffer with given length
+        lexer(const lexer_char_t* buff, const size_t len) noexcept
+            : m_content(buff)
         {
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
             assert(m_content != nullptr);
             m_start = m_cursor = m_content;
-            m_limit = m_content + s.size();
+            m_limit = m_content + len;
         }
 
-        /// constructor with a given stream
-        explicit lexer(std::istream* s) noexcept
-            : m_stream(s), m_buffer()
+        /// a lexer from an input stream
+        explicit lexer(std::istream& s)
+            : m_stream(&s), m_line_buffer()
         {
-            assert(m_stream != nullptr);
-            std::getline(*m_stream, m_buffer);
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
-            assert(m_content != nullptr);
-            m_start = m_cursor = m_content;
-            m_limit = m_content + m_buffer.size();
-        }
+            // fill buffer
+            fill_line_buffer();
 
-        /// default constructor
-        lexer() = default;
+            // skip UTF-8 byte-order mark
+            if (m_line_buffer.size() >= 3 and m_line_buffer.substr(0, 3) == "\xEF\xBB\xBF")
+            {
+                m_line_buffer[0] = ' ';
+                m_line_buffer[1] = ' ';
+                m_line_buffer[2] = ' ';
+            }
+        }
 
-        // switch off unwanted functions
+        // switch off unwanted functions (due to pointer members)
+        lexer() = delete;
         lexer(const lexer&) = delete;
         lexer operator=(const lexer&) = delete;
 
@@ -7673,7 +7784,7 @@ class basic_json
         infinite sequence of whitespace or byte-order-marks. This contradicts
         the assumption of finite input, q.e.d.
         */
-        token_type scan() noexcept
+        token_type scan()
         {
             while (true)
             {
@@ -7706,33 +7817,33 @@ class basic_json
                         128, 128, 128, 128, 128, 128, 128, 128,
                         128, 128, 128, 128, 128, 128, 128, 128,
                         128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
+                        0,   0,   0,   0,   0,   0,   0,   0,
                     };
                     if ((m_limit - m_cursor) < 5)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(5);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yybm[0 + yych] & 32)
                     {
                         goto basic_json_parser_6;
                     }
-                    if (yych <= '\\')
+                    if (yych <= '[')
                     {
                         if (yych <= '-')
                         {
@@ -7781,62 +7892,58 @@ class basic_json
                                 {
                                     goto basic_json_parser_17;
                                 }
-                                if (yych == '[')
+                                if (yych <= 'Z')
                                 {
-                                    goto basic_json_parser_19;
+                                    goto basic_json_parser_4;
                                 }
-                                goto basic_json_parser_4;
+                                goto basic_json_parser_19;
                             }
                         }
                     }
                     else
                     {
-                        if (yych <= 't')
+                        if (yych <= 'n')
                         {
-                            if (yych <= 'f')
+                            if (yych <= 'e')
                             {
-                                if (yych <= ']')
+                                if (yych == ']')
                                 {
                                     goto basic_json_parser_21;
                                 }
-                                if (yych <= 'e')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_23;
+                                goto basic_json_parser_4;
                             }
                             else
                             {
-                                if (yych == 'n')
+                                if (yych <= 'f')
                                 {
-                                    goto basic_json_parser_24;
+                                    goto basic_json_parser_23;
                                 }
-                                if (yych <= 's')
+                                if (yych <= 'm')
                                 {
                                     goto basic_json_parser_4;
                                 }
-                                goto basic_json_parser_25;
+                                goto basic_json_parser_24;
                             }
                         }
                         else
                         {
-                            if (yych <= '|')
+                            if (yych <= 'z')
                             {
-                                if (yych == '{')
+                                if (yych == 't')
                                 {
-                                    goto basic_json_parser_26;
+                                    goto basic_json_parser_25;
                                 }
                                 goto basic_json_parser_4;
                             }
                             else
                             {
-                                if (yych <= '}')
+                                if (yych <= '{')
                                 {
-                                    goto basic_json_parser_28;
+                                    goto basic_json_parser_26;
                                 }
-                                if (yych == 0xEF)
+                                if (yych == '}')
                                 {
-                                    goto basic_json_parser_30;
+                                    goto basic_json_parser_28;
                                 }
                                 goto basic_json_parser_4;
                             }
@@ -7859,7 +7966,7 @@ basic_json_parser_6:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yybm[0 + yych] & 32)
@@ -7876,7 +7983,19 @@ basic_json_parser_9:
                     {
                         goto basic_json_parser_5;
                     }
-                    goto basic_json_parser_32;
+                    if (yych <= 0x7F)
+                    {
+                        goto basic_json_parser_31;
+                    }
+                    if (yych <= 0xC1)
+                    {
+                        goto basic_json_parser_5;
+                    }
+                    if (yych <= 0xF4)
+                    {
+                        goto basic_json_parser_31;
+                    }
+                    goto basic_json_parser_5;
 basic_json_parser_10:
                     ++m_cursor;
                     {
@@ -7905,18 +8024,18 @@ basic_json_parser_13:
                     {
                         if (yych == '.')
                         {
-                            goto basic_json_parser_37;
+                            goto basic_json_parser_43;
                         }
                     }
                     else
                     {
                         if (yych <= 'E')
                         {
-                            goto basic_json_parser_38;
+                            goto basic_json_parser_44;
                         }
                         if (yych == 'e')
                         {
-                            goto basic_json_parser_38;
+                            goto basic_json_parser_44;
                         }
                     }
 basic_json_parser_14:
@@ -7929,7 +8048,7 @@ basic_json_parser_15:
                     m_marker = ++m_cursor;
                     if ((m_limit - m_cursor) < 3)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(3);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yybm[0 + yych] & 64)
@@ -7940,7 +8059,7 @@ basic_json_parser_15:
                     {
                         if (yych == '.')
                         {
-                            goto basic_json_parser_37;
+                            goto basic_json_parser_43;
                         }
                         goto basic_json_parser_14;
                     }
@@ -7948,11 +8067,11 @@ basic_json_parser_15:
                     {
                         if (yych <= 'E')
                         {
-                            goto basic_json_parser_38;
+                            goto basic_json_parser_44;
                         }
                         if (yych == 'e')
                         {
-                            goto basic_json_parser_38;
+                            goto basic_json_parser_44;
                         }
                         goto basic_json_parser_14;
                     }
@@ -7979,7 +8098,7 @@ basic_json_parser_23:
                     yych = *(m_marker = ++m_cursor);
                     if (yych == 'a')
                     {
-                        goto basic_json_parser_39;
+                        goto basic_json_parser_45;
                     }
                     goto basic_json_parser_5;
 basic_json_parser_24:
@@ -7987,7 +8106,7 @@ basic_json_parser_24:
                     yych = *(m_marker = ++m_cursor);
                     if (yych == 'u')
                     {
-                        goto basic_json_parser_40;
+                        goto basic_json_parser_46;
                     }
                     goto basic_json_parser_5;
 basic_json_parser_25:
@@ -7995,7 +8114,7 @@ basic_json_parser_25:
                     yych = *(m_marker = ++m_cursor);
                     if (yych == 'r')
                     {
-                        goto basic_json_parser_41;
+                        goto basic_json_parser_47;
                     }
                     goto basic_json_parser_5;
 basic_json_parser_26:
@@ -8011,35 +8130,71 @@ basic_json_parser_28:
                         break;
                     }
 basic_json_parser_30:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 0xBB)
-                    {
-                        goto basic_json_parser_42;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_31:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
-basic_json_parser_32:
+basic_json_parser_31:
                     if (yybm[0 + yych] & 128)
                     {
-                        goto basic_json_parser_31;
+                        goto basic_json_parser_30;
                     }
-                    if (yych <= 0x1F)
+                    if (yych <= 0xE0)
                     {
-                        goto basic_json_parser_33;
+                        if (yych <= '\\')
+                        {
+                            if (yych <= 0x1F)
+                            {
+                                goto basic_json_parser_32;
+                            }
+                            if (yych <= '"')
+                            {
+                                goto basic_json_parser_33;
+                            }
+                            goto basic_json_parser_35;
+                        }
+                        else
+                        {
+                            if (yych <= 0xC1)
+                            {
+                                goto basic_json_parser_32;
+                            }
+                            if (yych <= 0xDF)
+                            {
+                                goto basic_json_parser_36;
+                            }
+                            goto basic_json_parser_37;
+                        }
                     }
-                    if (yych <= '"')
+                    else
                     {
-                        goto basic_json_parser_34;
+                        if (yych <= 0xEF)
+                        {
+                            if (yych == 0xED)
+                            {
+                                goto basic_json_parser_39;
+                            }
+                            goto basic_json_parser_38;
+                        }
+                        else
+                        {
+                            if (yych <= 0xF0)
+                            {
+                                goto basic_json_parser_40;
+                            }
+                            if (yych <= 0xF3)
+                            {
+                                goto basic_json_parser_41;
+                            }
+                            if (yych <= 0xF4)
+                            {
+                                goto basic_json_parser_42;
+                            }
+                        }
                     }
-                    goto basic_json_parser_36;
-basic_json_parser_33:
+basic_json_parser_32:
                     m_cursor = m_marker;
                     if (yyaccept == 0)
                     {
@@ -8049,17 +8204,17 @@ basic_json_parser_33:
                     {
                         goto basic_json_parser_14;
                     }
-basic_json_parser_34:
+basic_json_parser_33:
                     ++m_cursor;
                     {
                         last_token_type = token_type::value_string;
                         break;
                     }
-basic_json_parser_36:
+basic_json_parser_35:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yych <= 'e')
@@ -8068,13 +8223,13 @@ basic_json_parser_36:
                         {
                             if (yych == '"')
                             {
-                                goto basic_json_parser_31;
+                                goto basic_json_parser_30;
                             }
                             if (yych <= '.')
                             {
-                                goto basic_json_parser_33;
+                                goto basic_json_parser_32;
                             }
-                            goto basic_json_parser_31;
+                            goto basic_json_parser_30;
                         }
                         else
                         {
@@ -8082,17 +8237,17 @@ basic_json_parser_36:
                             {
                                 if (yych <= '[')
                                 {
-                                    goto basic_json_parser_33;
+                                    goto basic_json_parser_32;
                                 }
-                                goto basic_json_parser_31;
+                                goto basic_json_parser_30;
                             }
                             else
                             {
                                 if (yych == 'b')
                                 {
-                                    goto basic_json_parser_31;
+                                    goto basic_json_parser_30;
                                 }
-                                goto basic_json_parser_33;
+                                goto basic_json_parser_32;
                             }
                         }
                     }
@@ -8102,13 +8257,13 @@ basic_json_parser_36:
                         {
                             if (yych <= 'f')
                             {
-                                goto basic_json_parser_31;
+                                goto basic_json_parser_30;
                             }
                             if (yych == 'n')
                             {
-                                goto basic_json_parser_31;
+                                goto basic_json_parser_30;
                             }
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         else
                         {
@@ -8116,130 +8271,235 @@ basic_json_parser_36:
                             {
                                 if (yych <= 'r')
                                 {
-                                    goto basic_json_parser_31;
+                                    goto basic_json_parser_30;
                                 }
-                                goto basic_json_parser_33;
+                                goto basic_json_parser_32;
                             }
                             else
                             {
                                 if (yych <= 't')
                                 {
-                                    goto basic_json_parser_31;
+                                    goto basic_json_parser_30;
                                 }
                                 if (yych <= 'u')
                                 {
-                                    goto basic_json_parser_43;
+                                    goto basic_json_parser_48;
                                 }
-                                goto basic_json_parser_33;
+                                goto basic_json_parser_32;
                             }
                         }
                     }
+basic_json_parser_36:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 0x7F)
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= 0xBF)
+                    {
+                        goto basic_json_parser_30;
+                    }
+                    goto basic_json_parser_32;
 basic_json_parser_37:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 0x9F)
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= 0xBF)
+                    {
+                        goto basic_json_parser_36;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_38:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 0x7F)
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= 0xBF)
+                    {
+                        goto basic_json_parser_36;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_39:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 0x7F)
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= 0x9F)
+                    {
+                        goto basic_json_parser_36;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_40:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 0x8F)
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= 0xBF)
+                    {
+                        goto basic_json_parser_38;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_41:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 0x7F)
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= 0xBF)
+                    {
+                        goto basic_json_parser_38;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_42:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 0x7F)
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= 0x8F)
+                    {
+                        goto basic_json_parser_38;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_43:
                     yych = *++m_cursor;
                     if (yych <= '/')
                     {
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
                     if (yych <= '9')
                     {
-                        goto basic_json_parser_44;
+                        goto basic_json_parser_49;
                     }
-                    goto basic_json_parser_33;
-basic_json_parser_38:
+                    goto basic_json_parser_32;
+basic_json_parser_44:
                     yych = *++m_cursor;
                     if (yych <= ',')
                     {
                         if (yych == '+')
                         {
-                            goto basic_json_parser_46;
+                            goto basic_json_parser_51;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
                     else
                     {
                         if (yych <= '-')
                         {
-                            goto basic_json_parser_46;
+                            goto basic_json_parser_51;
                         }
                         if (yych <= '/')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_47;
+                            goto basic_json_parser_52;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
-basic_json_parser_39:
+basic_json_parser_45:
                     yych = *++m_cursor;
                     if (yych == 'l')
                     {
-                        goto basic_json_parser_49;
+                        goto basic_json_parser_54;
                     }
-                    goto basic_json_parser_33;
-basic_json_parser_40:
+                    goto basic_json_parser_32;
+basic_json_parser_46:
                     yych = *++m_cursor;
                     if (yych == 'l')
                     {
-                        goto basic_json_parser_50;
+                        goto basic_json_parser_55;
                     }
-                    goto basic_json_parser_33;
-basic_json_parser_41:
+                    goto basic_json_parser_32;
+basic_json_parser_47:
                     yych = *++m_cursor;
                     if (yych == 'u')
                     {
-                        goto basic_json_parser_51;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_42:
-                    yych = *++m_cursor;
-                    if (yych == 0xBF)
-                    {
-                        goto basic_json_parser_52;
+                        goto basic_json_parser_56;
                     }
-                    goto basic_json_parser_33;
-basic_json_parser_43:
+                    goto basic_json_parser_32;
+basic_json_parser_48:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yych <= '@')
                     {
                         if (yych <= '/')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_54;
+                            goto basic_json_parser_57;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
                     else
                     {
                         if (yych <= 'F')
                         {
-                            goto basic_json_parser_54;
+                            goto basic_json_parser_57;
                         }
                         if (yych <= '`')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= 'f')
                         {
-                            goto basic_json_parser_54;
+                            goto basic_json_parser_57;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
-basic_json_parser_44:
+basic_json_parser_49:
                     yyaccept = 1;
                     m_marker = ++m_cursor;
                     if ((m_limit - m_cursor) < 3)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(3);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yych <= 'D')
@@ -8250,7 +8510,7 @@ basic_json_parser_44:
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_44;
+                            goto basic_json_parser_49;
                         }
                         goto basic_json_parser_14;
                     }
@@ -8258,29 +8518,29 @@ basic_json_parser_44:
                     {
                         if (yych <= 'E')
                         {
-                            goto basic_json_parser_38;
+                            goto basic_json_parser_44;
                         }
                         if (yych == 'e')
                         {
-                            goto basic_json_parser_38;
+                            goto basic_json_parser_44;
                         }
                         goto basic_json_parser_14;
                     }
-basic_json_parser_46:
+basic_json_parser_51:
                     yych = *++m_cursor;
                     if (yych <= '/')
                     {
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
                     if (yych >= ':')
                     {
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
-basic_json_parser_47:
+basic_json_parser_52:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yych <= '/')
@@ -8289,164 +8549,159 @@ basic_json_parser_47:
                     }
                     if (yych <= '9')
                     {
-                        goto basic_json_parser_47;
+                        goto basic_json_parser_52;
                     }
                     goto basic_json_parser_14;
-basic_json_parser_49:
+basic_json_parser_54:
                     yych = *++m_cursor;
                     if (yych == 's')
                     {
-                        goto basic_json_parser_55;
+                        goto basic_json_parser_58;
                     }
-                    goto basic_json_parser_33;
-basic_json_parser_50:
+                    goto basic_json_parser_32;
+basic_json_parser_55:
                     yych = *++m_cursor;
                     if (yych == 'l')
                     {
-                        goto basic_json_parser_56;
+                        goto basic_json_parser_59;
                     }
-                    goto basic_json_parser_33;
-basic_json_parser_51:
+                    goto basic_json_parser_32;
+basic_json_parser_56:
                     yych = *++m_cursor;
                     if (yych == 'e')
                     {
-                        goto basic_json_parser_58;
-                    }
-                    goto basic_json_parser_33;
-basic_json_parser_52:
-                    ++m_cursor;
-                    {
-                        continue;
+                        goto basic_json_parser_61;
                     }
-basic_json_parser_54:
+                    goto basic_json_parser_32;
+basic_json_parser_57:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yych <= '@')
                     {
                         if (yych <= '/')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_60;
+                            goto basic_json_parser_63;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
                     else
                     {
                         if (yych <= 'F')
                         {
-                            goto basic_json_parser_60;
+                            goto basic_json_parser_63;
                         }
                         if (yych <= '`')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= 'f')
                         {
-                            goto basic_json_parser_60;
+                            goto basic_json_parser_63;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
-basic_json_parser_55:
+basic_json_parser_58:
                     yych = *++m_cursor;
                     if (yych == 'e')
                     {
-                        goto basic_json_parser_61;
+                        goto basic_json_parser_64;
                     }
-                    goto basic_json_parser_33;
-basic_json_parser_56:
+                    goto basic_json_parser_32;
+basic_json_parser_59:
                     ++m_cursor;
                     {
                         last_token_type = token_type::literal_null;
                         break;
                     }
-basic_json_parser_58:
+basic_json_parser_61:
                     ++m_cursor;
                     {
                         last_token_type = token_type::literal_true;
                         break;
                     }
-basic_json_parser_60:
+basic_json_parser_63:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yych <= '@')
                     {
                         if (yych <= '/')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_63;
+                            goto basic_json_parser_66;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
                     else
                     {
                         if (yych <= 'F')
                         {
-                            goto basic_json_parser_63;
+                            goto basic_json_parser_66;
                         }
                         if (yych <= '`')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= 'f')
                         {
-                            goto basic_json_parser_63;
+                            goto basic_json_parser_66;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
-basic_json_parser_61:
+basic_json_parser_64:
                     ++m_cursor;
                     {
                         last_token_type = token_type::literal_false;
                         break;
                     }
-basic_json_parser_63:
+basic_json_parser_66:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
-                        yyfill();    // LCOV_EXCL_LINE;
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
                     if (yych <= '@')
                     {
                         if (yych <= '/')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_31;
+                            goto basic_json_parser_30;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
                     else
                     {
                         if (yych <= 'F')
                         {
-                            goto basic_json_parser_31;
+                            goto basic_json_parser_30;
                         }
                         if (yych <= '`')
                         {
-                            goto basic_json_parser_33;
+                            goto basic_json_parser_32;
                         }
                         if (yych <= 'f')
                         {
-                            goto basic_json_parser_31;
+                            goto basic_json_parser_30;
                         }
-                        goto basic_json_parser_33;
+                        goto basic_json_parser_32;
                     }
                 }
 
@@ -8455,30 +8710,80 @@ basic_json_parser_63:
             return last_token_type;
         }
 
-        /// append data from the stream to the internal buffer
-        void yyfill() noexcept
+        /*!
+        @brief append data from the stream to the line buffer
+
+        This function is called by the scan() function when the end of the
+        buffer (`m_limit`) is reached and the `m_cursor` pointer cannot be
+        incremented without leaving the limits of the line buffer. Note re2c
+        decides when to call this function.
+
+        If the lexer reads from contiguous storage, there is no trailing null
+        byte. Therefore, this function must make sure to add these padding
+        null bytes.
+
+        If the lexer reads from an input stream, this function reads the next
+        line of the input.
+
+        @pre
+            p p p p p p u u u u u x . . . . . .
+            ^           ^       ^   ^
+            m_content   m_start |   m_limit
+                                m_cursor
+
+        @post
+            u u u u u x x x x x x x . . . . . .
+            ^       ^               ^
+            |       m_cursor        m_limit
+            m_start
+            m_content
+        */
+        void fill_line_buffer(size_t n = 0)
         {
-            if (m_stream == nullptr or not * m_stream)
-            {
-                return;
-            }
-
+            // number of processed characters (p)
             const auto offset_start = m_start - m_content;
-            const auto offset_marker = m_marker - m_start;
+            // offset for m_marker wrt. to m_start
+            const auto offset_marker = (m_marker == nullptr) ? 0 : m_marker - m_start;
+            // number of unprocessed characters (u)
             const auto offset_cursor = m_cursor - m_start;
 
-            m_buffer.erase(0, static_cast<size_t>(offset_start));
-            std::string line;
-            assert(m_stream != nullptr);
-            std::getline(*m_stream, line);
-            m_buffer += "\n" + line; // add line with newline symbol
+            // no stream is used or end of file is reached
+            if (m_stream == nullptr or m_stream->eof())
+            {
+                // skip this part if we are already using the line buffer
+                if (m_start != reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()))
+                {
+                    // copy unprocessed characters to line buffer
+                    m_line_buffer.clear();
+                    for (m_cursor = m_start; m_cursor != m_limit; ++m_cursor)
+                    {
+                        m_line_buffer.append(1, static_cast<const char>(*m_cursor));
+                    }
+                }
+
+                // append n characters to make sure that there is sufficient
+                // space between m_cursor and m_limit
+                m_line_buffer.append(1, '\x00');
+                m_line_buffer.append(n - 1, '\x01');
+            }
+            else
+            {
+                // delete processed characters from line buffer
+                m_line_buffer.erase(0, static_cast<size_t>(offset_start));
+                // read next line from input stream
+                std::string line;
+                std::getline(*m_stream, line, '\n');
+                // add line with newline symbol to the line buffer
+                m_line_buffer += line + "\n";
+            }
 
-            m_content = reinterpret_cast<const lexer_char_t*>(m_buffer.c_str());
+            // set pointers
+            m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.c_str());
             assert(m_content != nullptr);
             m_start  = m_content;
             m_marker = m_start + offset_marker;
             m_cursor = m_start + offset_cursor;
-            m_limit  = m_start + m_buffer.size() - 1;
+            m_limit  = m_start + m_line_buffer.size();
         }
 
         /// return string representation of last read token
@@ -8629,6 +8934,11 @@ basic_json_parser_63:
                                 // skip the next 10 characters (xxxx\uyyyy)
                                 i += 10;
                             }
+                            else if (codepoint >= 0xDC00 and codepoint <= 0xDFFF)
+                            {
+                                // we found a lone low surrogate
+                                throw std::invalid_argument("missing high surrogate");
+                            }
                             else
                             {
                                 // add unicode character(s)
@@ -8811,6 +9121,13 @@ basic_json_parser_63:
             {
                 // parse with strtod
                 result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
+
+                // replace infinity and NAN by null
+                if (not std::isfinite(result.m_value.number_float))
+                {
+                    type = value_t::null;
+                    result.m_value = basic_json::json_value();
+                }
             }
 
             // save the type
@@ -8820,8 +9137,8 @@ basic_json_parser_63:
       private:
         /// optional input stream
         std::istream* m_stream = nullptr;
-        /// the buffer
-        string_t m_buffer;
+        /// line buffer buffer for m_stream
+        string_t m_line_buffer {};
         /// the buffer pointer
         const lexer_char_t* m_content = nullptr;
         /// pointer to the beginning of the current symbol
@@ -8844,25 +9161,34 @@ basic_json_parser_63:
     class parser
     {
       public:
-        /// constructor for strings
-        parser(const string_t& s, const parser_callback_t cb = nullptr) noexcept
-            : callback(cb), m_lexer(s)
-        {
-            // read first token
-            get_token();
-        }
+        /// a parser reading from a string literal
+        parser(const char* buff, const parser_callback_t cb = nullptr)
+            : callback(cb),
+              m_lexer(reinterpret_cast<const typename lexer::lexer_char_t*>(buff), std::strlen(buff))
+        {}
 
         /// a parser reading from an input stream
-        parser(std::istream& _is, const parser_callback_t cb = nullptr) noexcept
-            : callback(cb), m_lexer(&_is)
-        {
-            // read first token
-            get_token();
-        }
+        parser(std::istream& is, const parser_callback_t cb = nullptr)
+            : callback(cb), m_lexer(is)
+        {}
+
+        /// a parser reading from an iterator range with contiguous storage
+        template<class IteratorType, typename std::enable_if<
+                     std::is_same<typename std::iterator_traits<IteratorType>::iterator_category, std::random_access_iterator_tag>::value
+                     , int>::type
+                 = 0>
+        parser(IteratorType first, IteratorType last, const parser_callback_t cb = nullptr)
+            : callback(cb),
+              m_lexer(reinterpret_cast<const typename lexer::lexer_char_t*>(&(*first)),
+                      static_cast<size_t>(std::distance(first, last)))
+        {}
 
         /// public parser interface
         basic_json parse()
         {
+            // read first token
+            get_token();
+
             basic_json result = parse_internal(true);
             result.assert_invariant();
 
@@ -8883,7 +9209,8 @@ basic_json_parser_63:
             {
                 case lexer::token_type::begin_object:
                 {
-                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::object_start, result))))
+                    if (keep and (not callback
+                                  or ((keep = callback(depth++, parse_event_t::object_start, result)) != 0)))
                     {
                         // explicitly set result to object to cope with {}
                         result.m_type = value_t::object;
@@ -8961,7 +9288,8 @@ basic_json_parser_63:
 
                 case lexer::token_type::begin_array:
                 {
-                    if (keep and (not callback or (keep = callback(depth++, parse_event_t::array_start, result))))
+                    if (keep and (not callback
+                                  or ((keep = callback(depth++, parse_event_t::array_start, result)) != 0)))
                     {
                         // explicitly set result to object to cope with []
                         result.m_type = value_t::array;
@@ -9067,7 +9395,7 @@ basic_json_parser_63:
         }
 
         /// get next token from lexer
-        typename lexer::token_type get_token() noexcept
+        typename lexer::token_type get_token()
         {
             last_token = m_lexer.scan();
             return last_token;
@@ -9280,6 +9608,12 @@ basic_json_parser_63:
         /*!
         @brief return a reference to the pointed to value
 
+        @note This version does not throw if a value is not present, but tries
+        to create nested values instead. For instance, calling this function
+        with pointer `"/this/that"` on a null value is equivalent to calling
+        `operator[]("this").operator[]("that")` on that value, effectively
+        changing the null value to an object.
+
         @param[in] ptr  a JSON value
 
         @return reference to the JSON value pointed to by the JSON pointer
@@ -9294,6 +9628,29 @@ basic_json_parser_63:
         {
             for (const auto& reference_token : reference_tokens)
             {
+                // convert null values to arrays or objects before continuing
+                if (ptr->m_type == value_t::null)
+                {
+                    // check if reference token is a number
+                    const bool nums = std::all_of(reference_token.begin(),
+                                                  reference_token.end(),
+                                                  [](const char x)
+                    {
+                        return std::isdigit(x);
+                    });
+
+                    // change value to array for numbers or "-" or to object
+                    // otherwise
+                    if (nums or reference_token == "-")
+                    {
+                        *ptr = value_t::array;
+                    }
+                    else
+                    {
+                        *ptr = value_t::object;
+                    }
+                }
+
                 switch (ptr->m_type)
                 {
                     case value_t::object:
@@ -9475,7 +9832,7 @@ basic_json_parser_63:
         }
 
         /// split the string input to reference tokens
-        static std::vector<std::string> split(std::string reference_string)
+        static std::vector<std::string> split(const std::string& reference_string)
         {
             std::vector<std::string> result;
 
@@ -9960,7 +10317,7 @@ basic_json_parser_63:
                 json_pointer top_pointer = ptr.top();
                 if (top_pointer != ptr)
                 {
-                    basic_json& x = result.at(top_pointer);
+                    result.at(top_pointer);
                 }
 
                 // get reference to parent of JSON pointer ptr
@@ -10203,7 +10560,7 @@ basic_json_parser_63:
     */
     static basic_json diff(const basic_json& source,
                            const basic_json& target,
-                           std::string path = "")
+                           const std::string& path = "")
     {
         // the patch
         basic_json result(value_t::array);
@@ -10365,7 +10722,7 @@ namespace std
 
 @since version 1.0.0
 */
-template <>
+template<>
 inline void swap(nlohmann::json& j1,
                  nlohmann::json& j2) noexcept(
                      is_nothrow_move_constructible<nlohmann::json>::value and
@@ -10376,7 +10733,7 @@ inline void swap(nlohmann::json& j1,
 }
 
 /// hash value for JSON objects
-template <>
+template<>
 struct hash<nlohmann::json>
 {
     /*!
@@ -10401,30 +10758,32 @@ can be used by adding `"_json"` to a string literal and returns a JSON object
 if no parse error occurred.
 
 @param[in] s  a string representation of a JSON object
+@param[in] n  the length of string @a s
 @return a JSON object
 
 @since version 1.0.0
 */
-inline nlohmann::json operator "" _json(const char* s, std::size_t)
+inline nlohmann::json operator "" _json(const char* s, std::size_t n)
 {
-    return nlohmann::json::parse(reinterpret_cast<const nlohmann::json::string_t::value_type*>(s));
+    return nlohmann::json::parse(s, s + n);
 }
 
 /*!
 @brief user-defined string literal for JSON pointer
 
 This operator implements a user-defined string literal for JSON Pointers. It
-can be used by adding `"_json"` to a string literal and returns a JSON pointer
+can be used by adding `"_json_pointer"` to a string literal and returns a JSON pointer
 object if no parse error occurred.
 
 @param[in] s  a string representation of a JSON Pointer
+@param[in] n  the length of string @a s
 @return a JSON pointer object
 
 @since version 2.0.0
 */
-inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t)
+inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t n)
 {
-    return nlohmann::json::json_pointer(s);
+    return nlohmann::json::json_pointer(std::string(s, n));
 }
 
 // restore GCC/clang diagnostic settings
-- 
cgit v1.2.3


From f1ed57c62d64d7ee9e7ab937b1ab51e5953ad495 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Fri, 20 Jan 2017 10:09:47 -0800
Subject: Update nlohmann/json (header only lib).

---
 ext/json/json.hpp | 2249 ++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 1865 insertions(+), 384 deletions(-)

(limited to 'ext/json/json.hpp')

diff --git a/ext/json/json.hpp b/ext/json/json.hpp
index a302bb02..9d48e7a6 100644
--- a/ext/json/json.hpp
+++ b/ext/json/json.hpp
@@ -1,11 +1,11 @@
 /*
     __ _____ _____ _____
  __|  |   __|     |   | |  JSON for Modern C++
-|  |  |__   |  |  | | | |  version 2.0.7
+|  |  |__   |  |  | | | |  version 2.0.10
 |_____|_____|_____|_|___|  https://github.com/nlohmann/json
 
 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
-Copyright (c) 2013-2016 Niels Lohmann <http://nlohmann.me>.
+Copyright (c) 2013-2017 Niels Lohmann <http://nlohmann.me>.
 
 Permission is hereby  granted, free of charge, to any  person obtaining a copy
 of this software and associated  documentation files (the "Software"), to deal
@@ -34,7 +34,7 @@ SOFTWARE.
 #include <cassert> // assert
 #include <cctype> // isdigit
 #include <ciso646> // and, not, or
-#include <cmath> // isfinite, signbit
+#include <cmath> // isfinite, ldexp, signbit
 #include <cstddef> // nullptr_t, ptrdiff_t, size_t
 #include <cstdint> // int64_t, uint64_t
 #include <cstdlib> // strtod, strtof, strtold, strtoul
@@ -45,7 +45,7 @@ SOFTWARE.
 #include <iostream> // istream, ostream
 #include <iterator> // advance, begin, bidirectional_iterator_tag, distance, end, inserter, iterator, iterator_traits, next, random_access_iterator_tag, reverse_iterator
 #include <limits> // numeric_limits
-#include <locale> // locale, numpunct
+#include <locale> // locale
 #include <map> // map
 #include <memory> // addressof, allocator, allocator_traits, unique_ptr
 #include <numeric> // accumulate
@@ -75,6 +75,12 @@ SOFTWARE.
     #pragma GCC diagnostic ignored "-Wfloat-equal"
 #endif
 
+// disable documentation warnings on clang
+#if defined(__clang__)
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wdocumentation"
+#endif
+
 // allow for portable deprecation warnings
 #if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
     #define JSON_DEPRECATED __attribute__((deprecated))
@@ -122,26 +128,6 @@ struct has_mapped_type
         std::is_integral<decltype(detect(std::declval<T>()))>::value;
 };
 
-/*!
-@brief helper class to create locales with decimal point
-
-This struct is used a default locale during the JSON serialization. JSON
-requires the decimal point to be `.`, so this function overloads the
-`do_decimal_point()` function to return `.`. This function is called by
-float-to-string conversions to retrieve the decimal separator between integer
-and fractional parts.
-
-@sa https://github.com/nlohmann/json/issues/51#issuecomment-86869315
-@since version 2.0.0
-*/
-struct DecimalSeparator : std::numpunct<char>
-{
-    char do_decimal_point() const
-    {
-        return '.';
-    }
-};
-
 }
 
 /*!
@@ -242,6 +228,7 @@ class basic_json
 
   public:
     // forward declarations
+    template<typename U> class iter_impl;
     template<typename Base> class json_reverse_iterator;
     class json_pointer;
 
@@ -276,9 +263,9 @@ class basic_json
     using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
 
     /// an iterator for a basic_json container
-    class iterator;
+    using iterator = iter_impl<basic_json>;
     /// a const iterator for a basic_json container
-    class const_iterator;
+    using const_iterator = iter_impl<const basic_json>;
     /// a reverse iterator for a basic_json container
     using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
     /// a const reverse iterator for a basic_json container
@@ -886,8 +873,17 @@ class basic_json
                     break;
                 }
 
+                case value_t::null:
+                {
+                    break;
+                }
+
                 default:
                 {
+                    if (t == value_t::null)
+                    {
+                        throw std::domain_error("961c151d2e87f2686a955a9be24d316f1362bf21 2.0.10"); // LCOV_EXCL_LINE
+                    }
                     break;
                 }
             }
@@ -964,7 +960,7 @@ class basic_json
 
     With a parser callback function, the result of parsing a JSON text can be
     influenced. When passed to @ref parse(std::istream&, const
-    parser_callback_t) or @ref parse(const char*, const parser_callback_t),
+    parser_callback_t) or @ref parse(const CharT, const parser_callback_t),
     it is called on certain events (passed as @ref parse_event_t via parameter
     @a event) with a set recursion depth @a depth and context JSON value
     @a parsed. The return value of the callback function is a boolean
@@ -1007,7 +1003,7 @@ class basic_json
     skipped completely or replaced by an empty discarded object.
 
     @sa @ref parse(std::istream&, parser_callback_t) or
-    @ref parse(const char*, parser_callback_t) for examples
+    @ref parse(const CharT, const parser_callback_t) for examples
 
     @since version 1.0.0
     */
@@ -2201,8 +2197,7 @@ class basic_json
     {
         std::stringstream ss;
         // fix locale problems
-        const static std::locale loc(std::locale(), new DecimalSeparator);
-        ss.imbue(loc);
+        ss.imbue(std::locale::classic());
 
         // 6, 15 or 16 digits of precision allows round-trip IEEE 754
         // string->float->string, string->double->string or string->long
@@ -3807,7 +3802,7 @@ class basic_json
     container `c`, the expression `c.front()` is equivalent to `*c.begin()`.
 
     @return In case of a structured type (array or object), a reference to the
-    first element is returned. In cast of number, string, or boolean values, a
+    first element is returned. In case of number, string, or boolean values, a
     reference to the value is returned.
 
     @complexity Constant.
@@ -3850,7 +3845,7 @@ class basic_json
     @endcode
 
     @return In case of a structured type (array or object), a reference to the
-    last element is returned. In cast of number, string, or boolean values, a
+    last element is returned. In case of number, string, or boolean values, a
     reference to the value is returned.
 
     @complexity Constant.
@@ -4201,10 +4196,14 @@ class basic_json
     element is not found or the JSON value is not an object, end() is
     returned.
 
+    @note This method always returns @ref end() when executed on a JSON type
+          that is not an object.
+
     @param[in] key key value of the element to search for
 
     @return Iterator to an element with key equivalent to @a key. If no such
-    element is found, past-the-end (see end()) iterator is returned.
+    element is found or the JSON value is not an object, past-the-end (see
+    @ref end()) iterator is returned.
 
     @complexity Logarithmic in the size of the JSON object.
 
@@ -4247,6 +4246,9 @@ class basic_json
     default `std::map` type, the return value will always be `0` (@a key was
     not found) or `1` (@a key was found).
 
+    @note This method always returns `0` when executed on a JSON type that is
+          not an object.
+
     @param[in] key key value of the element to count
 
     @return Number of elements with key @a key. If the JSON value is not an
@@ -4806,9 +4808,6 @@ class basic_json
     object      | `{}`
     array       | `[]`
 
-    @note Floating-point numbers are set to `0.0` which will be serialized to
-    `0`. The vale type remains @ref number_float_t.
-
     @complexity Linear in the size of the JSON value.
 
     @liveexample{The example below shows the effect of `clear()` to different
@@ -5053,6 +5052,102 @@ class basic_json
         return *this;
     }
 
+    /*!
+    @brief add an object to an array
+
+    Creates a JSON value from the passed parameters @a args to the end of the
+    JSON value. If the function is called on a JSON null value, an empty array
+    is created before appending the value created from @a args.
+
+    @param[in] args arguments to forward to a constructor of @ref basic_json
+    @tparam Args compatible types to create a @ref basic_json object
+
+    @throw std::domain_error when called on a type other than JSON array or
+    null; example: `"cannot use emplace_back() with number"`
+
+    @complexity Amortized constant.
+
+    @liveexample{The example shows how `push_back()` can be used to add
+    elements to a JSON array. Note how the `null` value was silently converted
+    to a JSON array.,emplace_back}
+
+    @since version 2.0.8
+    */
+    template<class... Args>
+    void emplace_back(Args&& ... args)
+    {
+        // emplace_back only works for null objects or arrays
+        if (not(is_null() or is_array()))
+        {
+            throw std::domain_error("cannot use emplace_back() with " + type_name());
+        }
+
+        // transform null object into an array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value = value_t::array;
+            assert_invariant();
+        }
+
+        // add element to array (perfect forwarding)
+        m_value.array->emplace_back(std::forward<Args>(args)...);
+    }
+
+    /*!
+    @brief add an object to an object if key does not exist
+
+    Inserts a new element into a JSON object constructed in-place with the given
+    @a args if there is no element with the key in the container. If the
+    function is called on a JSON null value, an empty object is created before
+    appending the value created from @a args.
+
+    @param[in] args arguments to forward to a constructor of @ref basic_json
+    @tparam Args compatible types to create a @ref basic_json object
+
+    @return a pair consisting of an iterator to the inserted element, or the
+            already-existing element if no insertion happened, and a bool
+            denoting whether the insertion took place.
+
+    @throw std::domain_error when called on a type other than JSON object or
+    null; example: `"cannot use emplace() with number"`
+
+    @complexity Logarithmic in the size of the container, O(log(`size()`)).
+
+    @liveexample{The example shows how `emplace()` can be used to add elements
+    to a JSON object. Note how the `null` value was silently converted to a
+    JSON object. Further note how no value is added if there was already one
+    value stored with the same key.,emplace}
+
+    @since version 2.0.8
+    */
+    template<class... Args>
+    std::pair<iterator, bool> emplace(Args&& ... args)
+    {
+        // emplace only works for null objects or arrays
+        if (not(is_null() or is_object()))
+        {
+            throw std::domain_error("cannot use emplace() with " + type_name());
+        }
+
+        // transform null object into an object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value = value_t::object;
+            assert_invariant();
+        }
+
+        // add element to array (perfect forwarding)
+        auto res = m_value.object->emplace(std::forward<Args>(args)...);
+        // create result iterator and set iterator to the result of emplace
+        auto it = begin();
+        it.m_it.object_iterator = res.first;
+
+        // return pair of iterator and boolean
+        return {it, res.second};
+    }
+
     /*!
     @brief inserts element
 
@@ -5829,7 +5924,7 @@ class basic_json
         o.width(0);
 
         // fix locale problems
-        const auto old_locale = o.imbue(std::locale(std::locale(), new DecimalSeparator));
+        const auto old_locale = o.imbue(std::locale::classic());
         // set precision
 
         // 6, 15 or 16 digits of precision allows round-trip IEEE 754
@@ -5928,11 +6023,11 @@ class basic_json
 
     @since version 1.0.0 (originally for @ref string_t)
     */
-    template<typename CharPT, typename std::enable_if<
-                 std::is_pointer<CharPT>::value and
-                 std::is_integral<typename std::remove_pointer<CharPT>::type>::value and
-                 sizeof(typename std::remove_pointer<CharPT>::type) == 1, int>::type = 0>
-    static basic_json parse(const CharPT s,
+    template<typename CharT, typename std::enable_if<
+                 std::is_pointer<CharT>::value and
+                 std::is_integral<typename std::remove_pointer<CharT>::type>::value and
+                 sizeof(typename std::remove_pointer<CharT>::type) == 1, int>::type = 0>
+    static basic_json parse(const CharT s,
                             const parser_callback_t cb = nullptr)
     {
         return parser(reinterpret_cast<const char*>(s), cb).parse();
@@ -5957,7 +6052,7 @@ class basic_json
     @liveexample{The example below demonstrates the `parse()` function with
     and without callback function.,parse__istream__parser_callback_t}
 
-    @sa @ref parse(const char*, const parser_callback_t) for a version
+    @sa @ref parse(const CharT, const parser_callback_t) for a version
     that reads from a string
 
     @since version 1.0.0
@@ -6142,160 +6237,1650 @@ class basic_json
 
     /// @}
 
+    //////////////////////////////////////////
+    // binary serialization/deserialization //
+    //////////////////////////////////////////
+
+    /// @name binary serialization/deserialization support
+    /// @{
 
   private:
-    ///////////////////////////
-    // convenience functions //
-    ///////////////////////////
+    template<typename T>
+    static void add_to_vector(std::vector<uint8_t>& vec, size_t bytes, const T number)
+    {
+        assert(bytes == 1 or bytes == 2 or bytes == 4 or bytes == 8);
+
+        switch (bytes)
+        {
+            case 8:
+            {
+                vec.push_back(static_cast<uint8_t>((number >> 070) & 0xff));
+                vec.push_back(static_cast<uint8_t>((number >> 060) & 0xff));
+                vec.push_back(static_cast<uint8_t>((number >> 050) & 0xff));
+                vec.push_back(static_cast<uint8_t>((number >> 040) & 0xff));
+                // intentional fall-through
+            }
+
+            case 4:
+            {
+                vec.push_back(static_cast<uint8_t>((number >> 030) & 0xff));
+                vec.push_back(static_cast<uint8_t>((number >> 020) & 0xff));
+                // intentional fall-through
+            }
+
+            case 2:
+            {
+                vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff));
+                // intentional fall-through
+            }
+
+            case 1:
+            {
+                vec.push_back(static_cast<uint8_t>(number & 0xff));
+                break;
+            }
+        }
+    }
 
     /*!
-    @brief return the type as string
+    @brief take sufficient bytes from a vector to fill an integer variable
 
-    Returns the type name as string to be used in error messages - usually to
-    indicate that a function was called on a wrong JSON type.
+    In the context of binary serialization formats, we need to read several
+    bytes from a byte vector and combine them to multi-byte integral data
+    types.
 
-    @return basically a string representation of a the @a m_type member
+    @param[in] vec  byte vector to read from
+    @param[in] current_index  the position in the vector after which to read
 
-    @complexity Constant.
+    @return the next sizeof(T) bytes from @a vec, in reverse order as T
 
-    @since version 1.0.0
+    @tparam T the integral return type
+
+    @throw std::out_of_range if there are less than sizeof(T)+1 bytes in the
+           vector @a vec to read
+
+    In the for loop, the bytes from the vector are copied in reverse order into
+    the return value. In the figures below, let sizeof(T)=4 and `i` be the loop
+    variable.
+
+    Precondition:
+
+    vec:   |   |   | a | b | c | d |      T: |   |   |   |   |
+                 ^               ^             ^                ^
+           current_index         i            ptr        sizeof(T)
+
+    Postcondition:
+
+    vec:   |   |   | a | b | c | d |      T: | d | c | b | a |
+                 ^   ^                                     ^
+                 |   i                                    ptr
+           current_index
+
+    @sa Code adapted from <http://stackoverflow.com/a/41031865/266378>.
     */
-    std::string type_name() const
+    template<typename T>
+    static T get_from_vector(const std::vector<uint8_t>& vec, const size_t current_index)
     {
-        switch (m_type)
+        if (current_index + sizeof(T) + 1 > vec.size())
         {
-            case value_t::null:
-                return "null";
-            case value_t::object:
-                return "object";
-            case value_t::array:
-                return "array";
-            case value_t::string:
-                return "string";
-            case value_t::boolean:
-                return "boolean";
-            case value_t::discarded:
-                return "discarded";
-            default:
-                return "number";
+            throw std::out_of_range("cannot read " + std::to_string(sizeof(T)) + " bytes from vector");
         }
+
+        T result;
+        uint8_t* ptr = reinterpret_cast<uint8_t*>(&result);
+        for (size_t i = 0; i < sizeof(T); ++i)
+        {
+            *ptr++ = vec[current_index + sizeof(T) - i];
+        }
+        return result;
     }
 
     /*!
-    @brief calculates the extra space to escape a JSON string
+    @brief create a MessagePack serialization of a given JSON value
 
-    @param[in] s  the string to escape
-    @return the number of characters required to escape string @a s
+    This is a straightforward implementation of the MessagePack specification.
 
-    @complexity Linear in the length of string @a s.
+    @param[in] j  JSON value to serialize
+    @param[in,out] v  byte vector to write the serialization to
+
+    @sa https://github.com/msgpack/msgpack/blob/master/spec.md
     */
-    static std::size_t extra_space(const string_t& s) noexcept
+    static void to_msgpack_internal(const basic_json& j, std::vector<uint8_t>& v)
     {
-        return std::accumulate(s.begin(), s.end(), size_t{},
-                               [](size_t res, typename string_t::value_type c)
+        switch (j.type())
         {
-            switch (c)
+            case value_t::null:
             {
-                case '"':
-                case '\\':
-                case '\b':
-                case '\f':
-                case '\n':
-                case '\r':
-                case '\t':
+                // nil
+                v.push_back(0xc0);
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                // true and false
+                v.push_back(j.m_value.boolean ? 0xc3 : 0xc2);
+                break;
+            }
+
+            case value_t::number_integer:
+            {
+                if (j.m_value.number_integer >= 0)
                 {
-                    // from c (1 byte) to \x (2 bytes)
-                    return res + 1;
+                    // MessagePack does not differentiate between positive
+                    // signed integers and unsigned integers. Therefore, we used
+                    // the code from the value_t::number_unsigned case here.
+                    if (j.m_value.number_unsigned < 128)
+                    {
+                        // positive fixnum
+                        add_to_vector(v, 1, j.m_value.number_unsigned);
+                    }
+                    else if (j.m_value.number_unsigned <= UINT8_MAX)
+                    {
+                        // uint 8
+                        v.push_back(0xcc);
+                        add_to_vector(v, 1, j.m_value.number_unsigned);
+                    }
+                    else if (j.m_value.number_unsigned <= UINT16_MAX)
+                    {
+                        // uint 16
+                        v.push_back(0xcd);
+                        add_to_vector(v, 2, j.m_value.number_unsigned);
+                    }
+                    else if (j.m_value.number_unsigned <= UINT32_MAX)
+                    {
+                        // uint 32
+                        v.push_back(0xce);
+                        add_to_vector(v, 4, j.m_value.number_unsigned);
+                    }
+                    else if (j.m_value.number_unsigned <= UINT64_MAX)
+                    {
+                        // uint 64
+                        v.push_back(0xcf);
+                        add_to_vector(v, 8, j.m_value.number_unsigned);
+                    }
                 }
-
-                default:
+                else
                 {
-                    if (c >= 0x00 and c <= 0x1f)
+                    if (j.m_value.number_integer >= -32)
                     {
-                        // from c (1 byte) to \uxxxx (6 bytes)
-                        return res + 5;
+                        // negative fixnum
+                        add_to_vector(v, 1, j.m_value.number_integer);
                     }
-                    else
+                    else if (j.m_value.number_integer >= INT8_MIN and j.m_value.number_integer <= INT8_MAX)
                     {
-                        return res;
+                        // int 8
+                        v.push_back(0xd0);
+                        add_to_vector(v, 1, j.m_value.number_integer);
+                    }
+                    else if (j.m_value.number_integer >= INT16_MIN and j.m_value.number_integer <= INT16_MAX)
+                    {
+                        // int 16
+                        v.push_back(0xd1);
+                        add_to_vector(v, 2, j.m_value.number_integer);
+                    }
+                    else if (j.m_value.number_integer >= INT32_MIN and j.m_value.number_integer <= INT32_MAX)
+                    {
+                        // int 32
+                        v.push_back(0xd2);
+                        add_to_vector(v, 4, j.m_value.number_integer);
+                    }
+                    else if (j.m_value.number_integer >= INT64_MIN and j.m_value.number_integer <= INT64_MAX)
+                    {
+                        // int 64
+                        v.push_back(0xd3);
+                        add_to_vector(v, 8, j.m_value.number_integer);
                     }
                 }
+                break;
             }
-        });
-    }
-
-    /*!
-    @brief escape a string
-
-    Escape a string by replacing certain special characters by a sequence of
-    an escape character (backslash) and another character and other control
-    characters by a sequence of "\u" followed by a four-digit hex
-    representation.
-
-    @param[in] s  the string to escape
-    @return  the escaped string
-
-    @complexity Linear in the length of string @a s.
-    */
-    static string_t escape_string(const string_t& s)
-    {
-        const auto space = extra_space(s);
-        if (space == 0)
-        {
-            return s;
-        }
-
-        // create a result string of necessary size
-        string_t result(s.size() + space, '\\');
-        std::size_t pos = 0;
 
-        for (const auto& c : s)
-        {
-            switch (c)
+            case value_t::number_unsigned:
             {
-                // quotation mark (0x22)
-                case '"':
+                if (j.m_value.number_unsigned < 128)
                 {
-                    result[pos + 1] = '"';
-                    pos += 2;
-                    break;
+                    // positive fixnum
+                    add_to_vector(v, 1, j.m_value.number_unsigned);
                 }
-
-                // reverse solidus (0x5c)
-                case '\\':
+                else if (j.m_value.number_unsigned <= UINT8_MAX)
                 {
-                    // nothing to change
-                    pos += 2;
-                    break;
+                    // uint 8
+                    v.push_back(0xcc);
+                    add_to_vector(v, 1, j.m_value.number_unsigned);
                 }
-
-                // backspace (0x08)
-                case '\b':
+                else if (j.m_value.number_unsigned <= UINT16_MAX)
                 {
-                    result[pos + 1] = 'b';
-                    pos += 2;
-                    break;
+                    // uint 16
+                    v.push_back(0xcd);
+                    add_to_vector(v, 2, j.m_value.number_unsigned);
                 }
-
-                // formfeed (0x0c)
-                case '\f':
+                else if (j.m_value.number_unsigned <= UINT32_MAX)
                 {
-                    result[pos + 1] = 'f';
-                    pos += 2;
-                    break;
+                    // uint 32
+                    v.push_back(0xce);
+                    add_to_vector(v, 4, j.m_value.number_unsigned);
                 }
-
-                // newline (0x0a)
-                case '\n':
+                else if (j.m_value.number_unsigned <= UINT64_MAX)
                 {
-                    result[pos + 1] = 'n';
-                    pos += 2;
-                    break;
+                    // uint 64
+                    v.push_back(0xcf);
+                    add_to_vector(v, 8, j.m_value.number_unsigned);
                 }
+                break;
+            }
 
-                // carriage return (0x0d)
-                case '\r':
-                {
+            case value_t::number_float:
+            {
+                // float 64
+                v.push_back(0xcb);
+                const uint8_t* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float));
+                for (size_t i = 0; i < 8; ++i)
+                {
+                    v.push_back(helper[7 - i]);
+                }
+                break;
+            }
+
+            case value_t::string:
+            {
+                const auto N = j.m_value.string->size();
+                if (N <= 31)
+                {
+                    // fixstr
+                    v.push_back(static_cast<uint8_t>(0xa0 | N));
+                }
+                else if (N <= 255)
+                {
+                    // str 8
+                    v.push_back(0xd9);
+                    add_to_vector(v, 1, N);
+                }
+                else if (N <= 65535)
+                {
+                    // str 16
+                    v.push_back(0xda);
+                    add_to_vector(v, 2, N);
+                }
+                else if (N <= 4294967295)
+                {
+                    // str 32
+                    v.push_back(0xdb);
+                    add_to_vector(v, 4, N);
+                }
+
+                // append string
+                std::copy(j.m_value.string->begin(), j.m_value.string->end(),
+                          std::back_inserter(v));
+                break;
+            }
+
+            case value_t::array:
+            {
+                const auto N = j.m_value.array->size();
+                if (N <= 15)
+                {
+                    // fixarray
+                    v.push_back(static_cast<uint8_t>(0x90 | N));
+                }
+                else if (N <= 0xffff)
+                {
+                    // array 16
+                    v.push_back(0xdc);
+                    add_to_vector(v, 2, N);
+                }
+                else if (N <= 0xffffffff)
+                {
+                    // array 32
+                    v.push_back(0xdd);
+                    add_to_vector(v, 4, N);
+                }
+
+                // append each element
+                for (const auto& el : *j.m_value.array)
+                {
+                    to_msgpack_internal(el, v);
+                }
+                break;
+            }
+
+            case value_t::object:
+            {
+                const auto N = j.m_value.object->size();
+                if (N <= 15)
+                {
+                    // fixmap
+                    v.push_back(static_cast<uint8_t>(0x80 | (N & 0xf)));
+                }
+                else if (N <= 65535)
+                {
+                    // map 16
+                    v.push_back(0xde);
+                    add_to_vector(v, 2, N);
+                }
+                else if (N <= 4294967295)
+                {
+                    // map 32
+                    v.push_back(0xdf);
+                    add_to_vector(v, 4, N);
+                }
+
+                // append each element
+                for (const auto& el : *j.m_value.object)
+                {
+                    to_msgpack_internal(el.first, v);
+                    to_msgpack_internal(el.second, v);
+                }
+                break;
+            }
+
+            default:
+            {
+                break;
+            }
+        }
+    }
+
+    /*!
+    @brief create a CBOR serialization of a given JSON value
+
+    This is a straightforward implementation of the CBOR specification.
+
+    @param[in] j  JSON value to serialize
+    @param[in,out] v  byte vector to write the serialization to
+
+    @sa https://tools.ietf.org/html/rfc7049
+    */
+    static void to_cbor_internal(const basic_json& j, std::vector<uint8_t>& v)
+    {
+        switch (j.type())
+        {
+            case value_t::null:
+            {
+                v.push_back(0xf6);
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                v.push_back(j.m_value.boolean ? 0xf5 : 0xf4);
+                break;
+            }
+
+            case value_t::number_integer:
+            {
+                if (j.m_value.number_integer >= 0)
+                {
+                    // CBOR does not differentiate between positive signed
+                    // integers and unsigned integers. Therefore, we used the
+                    // code from the value_t::number_unsigned case here.
+                    if (j.m_value.number_integer <= 0x17)
+                    {
+                        add_to_vector(v, 1, j.m_value.number_integer);
+                    }
+                    else if (j.m_value.number_integer <= UINT8_MAX)
+                    {
+                        v.push_back(0x18);
+                        // one-byte uint8_t
+                        add_to_vector(v, 1, j.m_value.number_integer);
+                    }
+                    else if (j.m_value.number_integer <= UINT16_MAX)
+                    {
+                        v.push_back(0x19);
+                        // two-byte uint16_t
+                        add_to_vector(v, 2, j.m_value.number_integer);
+                    }
+                    else if (j.m_value.number_integer <= UINT32_MAX)
+                    {
+                        v.push_back(0x1a);
+                        // four-byte uint32_t
+                        add_to_vector(v, 4, j.m_value.number_integer);
+                    }
+                    else
+                    {
+                        v.push_back(0x1b);
+                        // eight-byte uint64_t
+                        add_to_vector(v, 8, j.m_value.number_integer);
+                    }
+                }
+                else
+                {
+                    // The conversions below encode the sign in the first byte,
+                    // and the value is converted to a positive number.
+                    const auto positive_number = -1 - j.m_value.number_integer;
+                    if (j.m_value.number_integer >= -24)
+                    {
+                        v.push_back(static_cast<uint8_t>(0x20 + positive_number));
+                    }
+                    else if (positive_number <= UINT8_MAX)
+                    {
+                        // int 8
+                        v.push_back(0x38);
+                        add_to_vector(v, 1, positive_number);
+                    }
+                    else if (positive_number <= UINT16_MAX)
+                    {
+                        // int 16
+                        v.push_back(0x39);
+                        add_to_vector(v, 2, positive_number);
+                    }
+                    else if (positive_number <= UINT32_MAX)
+                    {
+                        // int 32
+                        v.push_back(0x3a);
+                        add_to_vector(v, 4, positive_number);
+                    }
+                    else
+                    {
+                        // int 64
+                        v.push_back(0x3b);
+                        add_to_vector(v, 8, positive_number);
+                    }
+                }
+                break;
+            }
+
+            case value_t::number_unsigned:
+            {
+                if (j.m_value.number_unsigned <= 0x17)
+                {
+                    v.push_back(static_cast<uint8_t>(j.m_value.number_unsigned));
+                }
+                else if (j.m_value.number_unsigned <= 0xff)
+                {
+                    v.push_back(0x18);
+                    // one-byte uint8_t
+                    add_to_vector(v, 1, j.m_value.number_unsigned);
+                }
+                else if (j.m_value.number_unsigned <= 0xffff)
+                {
+                    v.push_back(0x19);
+                    // two-byte uint16_t
+                    add_to_vector(v, 2, j.m_value.number_unsigned);
+                }
+                else if (j.m_value.number_unsigned <= 0xffffffff)
+                {
+                    v.push_back(0x1a);
+                    // four-byte uint32_t
+                    add_to_vector(v, 4, j.m_value.number_unsigned);
+                }
+                else if (j.m_value.number_unsigned <= 0xffffffffffffffff)
+                {
+                    v.push_back(0x1b);
+                    // eight-byte uint64_t
+                    add_to_vector(v, 8, j.m_value.number_unsigned);
+                }
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                // Double-Precision Float
+                v.push_back(0xfb);
+                const uint8_t* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float));
+                for (size_t i = 0; i < 8; ++i)
+                {
+                    v.push_back(helper[7 - i]);
+                }
+                break;
+            }
+
+            case value_t::string:
+            {
+                const auto N = j.m_value.string->size();
+                if (N <= 0x17)
+                {
+                    v.push_back(0x60 + N);  // 1 byte for string + size
+                }
+                else if (N <= 0xff)
+                {
+                    v.push_back(0x78);  // one-byte uint8_t for N
+                    add_to_vector(v, 1, N);
+                }
+                else if (N <= 0xffff)
+                {
+                    v.push_back(0x79);  // two-byte uint16_t for N
+                    add_to_vector(v, 2, N);
+                }
+                else if (N <= 0xffffffff)
+                {
+                    v.push_back(0x7a); // four-byte uint32_t for N
+                    add_to_vector(v, 4, N);
+                }
+                // LCOV_EXCL_START
+                else if (N <= 0xffffffffffffffff)
+                {
+                    v.push_back(0x7b);  // eight-byte uint64_t for N
+                    add_to_vector(v, 8, N);
+                }
+                // LCOV_EXCL_STOP
+
+                // append string
+                std::copy(j.m_value.string->begin(), j.m_value.string->end(),
+                          std::back_inserter(v));
+                break;
+            }
+
+            case value_t::array:
+            {
+                const auto N = j.m_value.array->size();
+                if (N <= 0x17)
+                {
+                    v.push_back(0x80 + N);  // 1 byte for array + size
+                }
+                else if (N <= 0xff)
+                {
+                    v.push_back(0x98);  // one-byte uint8_t for N
+                    add_to_vector(v, 1, N);
+                }
+                else if (N <= 0xffff)
+                {
+                    v.push_back(0x99);  // two-byte uint16_t for N
+                    add_to_vector(v, 2, N);
+                }
+                else if (N <= 0xffffffff)
+                {
+                    v.push_back(0x9a);  // four-byte uint32_t for N
+                    add_to_vector(v, 4, N);
+                }
+                // LCOV_EXCL_START
+                else if (N <= 0xffffffffffffffff)
+                {
+                    v.push_back(0x9b);  // eight-byte uint64_t for N
+                    add_to_vector(v, 8, N);
+                }
+                // LCOV_EXCL_STOP
+
+                // append each element
+                for (const auto& el : *j.m_value.array)
+                {
+                    to_cbor_internal(el, v);
+                }
+                break;
+            }
+
+            case value_t::object:
+            {
+                const auto N = j.m_value.object->size();
+                if (N <= 0x17)
+                {
+                    v.push_back(0xa0 + N);  // 1 byte for object + size
+                }
+                else if (N <= 0xff)
+                {
+                    v.push_back(0xb8);
+                    add_to_vector(v, 1, N);  // one-byte uint8_t for N
+                }
+                else if (N <= 0xffff)
+                {
+                    v.push_back(0xb9);
+                    add_to_vector(v, 2, N);  // two-byte uint16_t for N
+                }
+                else if (N <= 0xffffffff)
+                {
+                    v.push_back(0xba);
+                    add_to_vector(v, 4, N);  // four-byte uint32_t for N
+                }
+                // LCOV_EXCL_START
+                else if (N <= 0xffffffffffffffff)
+                {
+                    v.push_back(0xbb);
+                    add_to_vector(v, 8, N);  // eight-byte uint64_t for N
+                }
+                // LCOV_EXCL_STOP
+
+                // append each element
+                for (const auto& el : *j.m_value.object)
+                {
+                    to_cbor_internal(el.first, v);
+                    to_cbor_internal(el.second, v);
+                }
+                break;
+            }
+
+            default:
+            {
+                break;
+            }
+        }
+    }
+
+
+    /*
+    @brief checks if given lengths do not exceed the size of a given vector
+
+    To secure the access to the byte vector during CBOR/MessagePack
+    deserialization, bytes are copied from the vector into buffers. This
+    function checks if the number of bytes to copy (@a len) does not exceed the
+    size @s size of the vector. Additionally, an @a offset is given from where
+    to start reading the bytes.
+
+    This function checks whether reading the bytes is safe; that is, offset is a
+    valid index in the vector, offset+len
+
+    @param[in] size    size of the byte vector
+    @param[in] len     number of bytes to read
+    @param[in] offset  offset where to start reading
+
+    vec:  x x x x x X X X X X
+          ^         ^         ^
+          0         offset    len
+
+    @throws out_of_range if `len > v.size()`
+    */
+    static void check_length(const size_t size, const size_t len, const size_t offset)
+    {
+        // simple case: requested length is greater than the vector's length
+        if (len > size or offset > size)
+        {
+            throw std::out_of_range("len out of range");
+        }
+
+        // second case: adding offset would result in overflow
+        if ((size > (std::numeric_limits<size_t>::max() - offset)))
+        {
+            throw std::out_of_range("len+offset out of range");
+        }
+
+        // last case: reading past the end of the vector
+        if (len + offset > size)
+        {
+            throw std::out_of_range("len+offset out of range");
+        }
+    }
+
+    /*!
+    @brief create a JSON value from a given MessagePack vector
+
+    @param[in] v  MessagePack serialization
+    @param[in] idx  byte index to start reading from @a v
+
+    @return deserialized JSON value
+
+    @throw std::invalid_argument if unsupported features from MessagePack were
+    used in the given vector @a v or if the input is not valid MessagePack
+    @throw std::out_of_range if the given vector ends prematurely
+
+    @sa https://github.com/msgpack/msgpack/blob/master/spec.md
+    */
+    static basic_json from_msgpack_internal(const std::vector<uint8_t>& v, size_t& idx)
+    {
+        // make sure reading 1 byte is safe
+        check_length(v.size(), 1, idx);
+
+        // store and increment index
+        const size_t current_idx = idx++;
+
+        if (v[current_idx] <= 0xbf)
+        {
+            if (v[current_idx] <= 0x7f) // positive fixint
+            {
+                return v[current_idx];
+            }
+            else if (v[current_idx] <= 0x8f) // fixmap
+            {
+                basic_json result = value_t::object;
+                const size_t len = v[current_idx] & 0x0f;
+                for (size_t i = 0; i < len; ++i)
+                {
+                    std::string key = from_msgpack_internal(v, idx);
+                    result[key] = from_msgpack_internal(v, idx);
+                }
+                return result;
+            }
+            else if (v[current_idx] <= 0x9f) // fixarray
+            {
+                basic_json result = value_t::array;
+                const size_t len = v[current_idx] & 0x0f;
+                for (size_t i = 0; i < len; ++i)
+                {
+                    result.push_back(from_msgpack_internal(v, idx));
+                }
+                return result;
+            }
+            else // fixstr
+            {
+                const size_t len = v[current_idx] & 0x1f;
+                const size_t offset = current_idx + 1;
+                idx += len; // skip content bytes
+                check_length(v.size(), len, offset);
+                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+            }
+        }
+        else if (v[current_idx] >= 0xe0) // negative fixint
+        {
+            return static_cast<int8_t>(v[current_idx]);
+        }
+        else
+        {
+            switch (v[current_idx])
+            {
+                case 0xc0: // nil
+                {
+                    return value_t::null;
+                }
+
+                case 0xc2: // false
+                {
+                    return false;
+                }
+
+                case 0xc3: // true
+                {
+                    return true;
+                }
+
+                case 0xca: // float 32
+                {
+                    // copy bytes in reverse order into the double variable
+                    check_length(v.size(), sizeof(float), 1);
+                    float res;
+                    for (size_t byte = 0; byte < sizeof(float); ++byte)
+                    {
+                        reinterpret_cast<uint8_t*>(&res)[sizeof(float) - byte - 1] = v[current_idx + 1 + byte];
+                    }
+                    idx += sizeof(float); // skip content bytes
+                    return res;
+                }
+
+                case 0xcb: // float 64
+                {
+                    // copy bytes in reverse order into the double variable
+                    check_length(v.size(), sizeof(double), 1);
+                    double res;
+                    for (size_t byte = 0; byte < sizeof(double); ++byte)
+                    {
+                        reinterpret_cast<uint8_t*>(&res)[sizeof(double) - byte - 1] = v[current_idx + 1 + byte];
+                    }
+                    idx += sizeof(double); // skip content bytes
+                    return res;
+                }
+
+                case 0xcc: // uint 8
+                {
+                    idx += 1; // skip content byte
+                    return get_from_vector<uint8_t>(v, current_idx);
+                }
+
+                case 0xcd: // uint 16
+                {
+                    idx += 2; // skip 2 content bytes
+                    return get_from_vector<uint16_t>(v, current_idx);
+                }
+
+                case 0xce: // uint 32
+                {
+                    idx += 4; // skip 4 content bytes
+                    return get_from_vector<uint32_t>(v, current_idx);
+                }
+
+                case 0xcf: // uint 64
+                {
+                    idx += 8; // skip 8 content bytes
+                    return get_from_vector<uint64_t>(v, current_idx);
+                }
+
+                case 0xd0: // int 8
+                {
+                    idx += 1; // skip content byte
+                    return get_from_vector<int8_t>(v, current_idx);
+                }
+
+                case 0xd1: // int 16
+                {
+                    idx += 2; // skip 2 content bytes
+                    return get_from_vector<int16_t>(v, current_idx);
+                }
+
+                case 0xd2: // int 32
+                {
+                    idx += 4; // skip 4 content bytes
+                    return get_from_vector<int32_t>(v, current_idx);
+                }
+
+                case 0xd3: // int 64
+                {
+                    idx += 8; // skip 8 content bytes
+                    return get_from_vector<int64_t>(v, current_idx);
+                }
+
+                case 0xd9: // str 8
+                {
+                    const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx));
+                    const size_t offset = current_idx + 2;
+                    idx += len + 1; // skip size byte + content bytes
+                    check_length(v.size(), len, offset);
+                    return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+                }
+
+                case 0xda: // str 16
+                {
+                    const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
+                    const size_t offset = current_idx + 3;
+                    idx += len + 2; // skip 2 size bytes + content bytes
+                    check_length(v.size(), len, offset);
+                    return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+                }
+
+                case 0xdb: // str 32
+                {
+                    const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
+                    const size_t offset = current_idx + 5;
+                    idx += len + 4; // skip 4 size bytes + content bytes
+                    check_length(v.size(), len, offset);
+                    return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+                }
+
+                case 0xdc: // array 16
+                {
+                    basic_json result = value_t::array;
+                    const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
+                    idx += 2; // skip 2 size bytes
+                    for (size_t i = 0; i < len; ++i)
+                    {
+                        result.push_back(from_msgpack_internal(v, idx));
+                    }
+                    return result;
+                }
+
+                case 0xdd: // array 32
+                {
+                    basic_json result = value_t::array;
+                    const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
+                    idx += 4; // skip 4 size bytes
+                    for (size_t i = 0; i < len; ++i)
+                    {
+                        result.push_back(from_msgpack_internal(v, idx));
+                    }
+                    return result;
+                }
+
+                case 0xde: // map 16
+                {
+                    basic_json result = value_t::object;
+                    const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
+                    idx += 2; // skip 2 size bytes
+                    for (size_t i = 0; i < len; ++i)
+                    {
+                        std::string key = from_msgpack_internal(v, idx);
+                        result[key] = from_msgpack_internal(v, idx);
+                    }
+                    return result;
+                }
+
+                case 0xdf: // map 32
+                {
+                    basic_json result = value_t::object;
+                    const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
+                    idx += 4; // skip 4 size bytes
+                    for (size_t i = 0; i < len; ++i)
+                    {
+                        std::string key = from_msgpack_internal(v, idx);
+                        result[key] = from_msgpack_internal(v, idx);
+                    }
+                    return result;
+                }
+
+                default:
+                {
+                    throw std::invalid_argument("error parsing a msgpack @ " + std::to_string(current_idx) + ": " + std::to_string(static_cast<int>(v[current_idx])));
+                }
+            }
+        }
+    }
+
+    /*!
+    @brief create a JSON value from a given CBOR vector
+
+    @param[in] v  CBOR serialization
+    @param[in] idx  byte index to start reading from @a v
+
+    @return deserialized JSON value
+
+    @throw std::invalid_argument if unsupported features from CBOR were used in
+    the given vector @a v or if the input is not valid CBOR
+    @throw std::out_of_range if the given vector ends prematurely
+
+    @sa https://tools.ietf.org/html/rfc7049
+    */
+    static basic_json from_cbor_internal(const std::vector<uint8_t>& v, size_t& idx)
+    {
+        // store and increment index
+        const size_t current_idx = idx++;
+
+        switch (v.at(current_idx))
+        {
+            // Integer 0x00..0x17 (0..23)
+            case 0x00:
+            case 0x01:
+            case 0x02:
+            case 0x03:
+            case 0x04:
+            case 0x05:
+            case 0x06:
+            case 0x07:
+            case 0x08:
+            case 0x09:
+            case 0x0a:
+            case 0x0b:
+            case 0x0c:
+            case 0x0d:
+            case 0x0e:
+            case 0x0f:
+            case 0x10:
+            case 0x11:
+            case 0x12:
+            case 0x13:
+            case 0x14:
+            case 0x15:
+            case 0x16:
+            case 0x17:
+            {
+                return v[current_idx];
+            }
+
+            case 0x18: // Unsigned integer (one-byte uint8_t follows)
+            {
+                idx += 1; // skip content byte
+                return get_from_vector<uint8_t>(v, current_idx);
+            }
+
+            case 0x19: // Unsigned integer (two-byte uint16_t follows)
+            {
+                idx += 2; // skip 2 content bytes
+                return get_from_vector<uint16_t>(v, current_idx);
+            }
+
+            case 0x1a: // Unsigned integer (four-byte uint32_t follows)
+            {
+                idx += 4; // skip 4 content bytes
+                return get_from_vector<uint32_t>(v, current_idx);
+            }
+
+            case 0x1b: // Unsigned integer (eight-byte uint64_t follows)
+            {
+                idx += 8; // skip 8 content bytes
+                return get_from_vector<uint64_t>(v, current_idx);
+            }
+
+            // Negative integer -1-0x00..-1-0x17 (-1..-24)
+            case 0x20:
+            case 0x21:
+            case 0x22:
+            case 0x23:
+            case 0x24:
+            case 0x25:
+            case 0x26:
+            case 0x27:
+            case 0x28:
+            case 0x29:
+            case 0x2a:
+            case 0x2b:
+            case 0x2c:
+            case 0x2d:
+            case 0x2e:
+            case 0x2f:
+            case 0x30:
+            case 0x31:
+            case 0x32:
+            case 0x33:
+            case 0x34:
+            case 0x35:
+            case 0x36:
+            case 0x37:
+            {
+                return static_cast<int8_t>(0x20 - 1 - v[current_idx]);
+            }
+
+            case 0x38: // Negative integer (one-byte uint8_t follows)
+            {
+                idx += 1; // skip content byte
+                // must be uint8_t !
+                return static_cast<number_integer_t>(-1) - get_from_vector<uint8_t>(v, current_idx);
+            }
+
+            case 0x39: // Negative integer -1-n (two-byte uint16_t follows)
+            {
+                idx += 2; // skip 2 content bytes
+                return static_cast<number_integer_t>(-1) - get_from_vector<uint16_t>(v, current_idx);
+            }
+
+            case 0x3a: // Negative integer -1-n (four-byte uint32_t follows)
+            {
+                idx += 4; // skip 4 content bytes
+                return static_cast<number_integer_t>(-1) - get_from_vector<uint32_t>(v, current_idx);
+            }
+
+            case 0x3b: // Negative integer -1-n (eight-byte uint64_t follows)
+            {
+                idx += 8; // skip 8 content bytes
+                return static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(get_from_vector<uint64_t>(v, current_idx));
+            }
+
+            // UTF-8 string (0x00..0x17 bytes follow)
+            case 0x60:
+            case 0x61:
+            case 0x62:
+            case 0x63:
+            case 0x64:
+            case 0x65:
+            case 0x66:
+            case 0x67:
+            case 0x68:
+            case 0x69:
+            case 0x6a:
+            case 0x6b:
+            case 0x6c:
+            case 0x6d:
+            case 0x6e:
+            case 0x6f:
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77:
+            {
+                const auto len = static_cast<size_t>(v[current_idx] - 0x60);
+                const size_t offset = current_idx + 1;
+                idx += len; // skip content bytes
+                check_length(v.size(), len, offset);
+                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+            }
+
+            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
+            {
+                const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx));
+                const size_t offset = current_idx + 2;
+                idx += len + 1; // skip size byte + content bytes
+                check_length(v.size(), len, offset);
+                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+            }
+
+            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
+            {
+                const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
+                const size_t offset = current_idx + 3;
+                idx += len + 2; // skip 2 size bytes + content bytes
+                check_length(v.size(), len, offset);
+                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+            }
+
+            case 0x7a: // UTF-8 string (four-byte uint32_t for n follow)
+            {
+                const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
+                const size_t offset = current_idx + 5;
+                idx += len + 4; // skip 4 size bytes + content bytes
+                check_length(v.size(), len, offset);
+                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+            }
+
+            case 0x7b: // UTF-8 string (eight-byte uint64_t for n follow)
+            {
+                const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx));
+                const size_t offset = current_idx + 9;
+                idx += len + 8; // skip 8 size bytes + content bytes
+                check_length(v.size(), len, offset);
+                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+            }
+
+            case 0x7f: // UTF-8 string (indefinite length)
+            {
+                std::string result;
+                while (v.at(idx) != 0xff)
+                {
+                    string_t s = from_cbor_internal(v, idx);
+                    result += s;
+                }
+                // skip break byte (0xFF)
+                idx += 1;
+                return result;
+            }
+
+            // array (0x00..0x17 data items follow)
+            case 0x80:
+            case 0x81:
+            case 0x82:
+            case 0x83:
+            case 0x84:
+            case 0x85:
+            case 0x86:
+            case 0x87:
+            case 0x88:
+            case 0x89:
+            case 0x8a:
+            case 0x8b:
+            case 0x8c:
+            case 0x8d:
+            case 0x8e:
+            case 0x8f:
+            case 0x90:
+            case 0x91:
+            case 0x92:
+            case 0x93:
+            case 0x94:
+            case 0x95:
+            case 0x96:
+            case 0x97:
+            {
+                basic_json result = value_t::array;
+                const auto len = static_cast<size_t>(v[current_idx] - 0x80);
+                for (size_t i = 0; i < len; ++i)
+                {
+                    result.push_back(from_cbor_internal(v, idx));
+                }
+                return result;
+            }
+
+            case 0x98: // array (one-byte uint8_t for n follows)
+            {
+                basic_json result = value_t::array;
+                const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx));
+                idx += 1; // skip 1 size byte
+                for (size_t i = 0; i < len; ++i)
+                {
+                    result.push_back(from_cbor_internal(v, idx));
+                }
+                return result;
+            }
+
+            case 0x99: // array (two-byte uint16_t for n follow)
+            {
+                basic_json result = value_t::array;
+                const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
+                idx += 2; // skip 4 size bytes
+                for (size_t i = 0; i < len; ++i)
+                {
+                    result.push_back(from_cbor_internal(v, idx));
+                }
+                return result;
+            }
+
+            case 0x9a: // array (four-byte uint32_t for n follow)
+            {
+                basic_json result = value_t::array;
+                const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
+                idx += 4; // skip 4 size bytes
+                for (size_t i = 0; i < len; ++i)
+                {
+                    result.push_back(from_cbor_internal(v, idx));
+                }
+                return result;
+            }
+
+            case 0x9b: // array (eight-byte uint64_t for n follow)
+            {
+                basic_json result = value_t::array;
+                const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx));
+                idx += 8; // skip 8 size bytes
+                for (size_t i = 0; i < len; ++i)
+                {
+                    result.push_back(from_cbor_internal(v, idx));
+                }
+                return result;
+            }
+
+            case 0x9f: // array (indefinite length)
+            {
+                basic_json result = value_t::array;
+                while (v.at(idx) != 0xff)
+                {
+                    result.push_back(from_cbor_internal(v, idx));
+                }
+                // skip break byte (0xFF)
+                idx += 1;
+                return result;
+            }
+
+            // map (0x00..0x17 pairs of data items follow)
+            case 0xa0:
+            case 0xa1:
+            case 0xa2:
+            case 0xa3:
+            case 0xa4:
+            case 0xa5:
+            case 0xa6:
+            case 0xa7:
+            case 0xa8:
+            case 0xa9:
+            case 0xaa:
+            case 0xab:
+            case 0xac:
+            case 0xad:
+            case 0xae:
+            case 0xaf:
+            case 0xb0:
+            case 0xb1:
+            case 0xb2:
+            case 0xb3:
+            case 0xb4:
+            case 0xb5:
+            case 0xb6:
+            case 0xb7:
+            {
+                basic_json result = value_t::object;
+                const auto len = static_cast<size_t>(v[current_idx] - 0xa0);
+                for (size_t i = 0; i < len; ++i)
+                {
+                    std::string key = from_cbor_internal(v, idx);
+                    result[key] = from_cbor_internal(v, idx);
+                }
+                return result;
+            }
+
+            case 0xb8: // map (one-byte uint8_t for n follows)
+            {
+                basic_json result = value_t::object;
+                const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx));
+                idx += 1; // skip 1 size byte
+                for (size_t i = 0; i < len; ++i)
+                {
+                    std::string key = from_cbor_internal(v, idx);
+                    result[key] = from_cbor_internal(v, idx);
+                }
+                return result;
+            }
+
+            case 0xb9: // map (two-byte uint16_t for n follow)
+            {
+                basic_json result = value_t::object;
+                const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
+                idx += 2; // skip 2 size bytes
+                for (size_t i = 0; i < len; ++i)
+                {
+                    std::string key = from_cbor_internal(v, idx);
+                    result[key] = from_cbor_internal(v, idx);
+                }
+                return result;
+            }
+
+            case 0xba: // map (four-byte uint32_t for n follow)
+            {
+                basic_json result = value_t::object;
+                const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
+                idx += 4; // skip 4 size bytes
+                for (size_t i = 0; i < len; ++i)
+                {
+                    std::string key = from_cbor_internal(v, idx);
+                    result[key] = from_cbor_internal(v, idx);
+                }
+                return result;
+            }
+
+            case 0xbb: // map (eight-byte uint64_t for n follow)
+            {
+                basic_json result = value_t::object;
+                const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx));
+                idx += 8; // skip 8 size bytes
+                for (size_t i = 0; i < len; ++i)
+                {
+                    std::string key = from_cbor_internal(v, idx);
+                    result[key] = from_cbor_internal(v, idx);
+                }
+                return result;
+            }
+
+            case 0xbf: // map (indefinite length)
+            {
+                basic_json result = value_t::object;
+                while (v.at(idx) != 0xff)
+                {
+                    std::string key = from_cbor_internal(v, idx);
+                    result[key] = from_cbor_internal(v, idx);
+                }
+                // skip break byte (0xFF)
+                idx += 1;
+                return result;
+            }
+
+            case 0xf4: // false
+            {
+                return false;
+            }
+
+            case 0xf5: // true
+            {
+                return true;
+            }
+
+            case 0xf6: // null
+            {
+                return value_t::null;
+            }
+
+            case 0xf9: // Half-Precision Float (two-byte IEEE 754)
+            {
+                check_length(v.size(), 2, 1);
+                idx += 2; // skip two content bytes
+
+                // code from RFC 7049, Appendix D, Figure 3:
+                // As half-precision floating-point numbers were only added to
+                // IEEE 754 in 2008, today's programming platforms often still
+                // only have limited support for them. It is very easy to
+                // include at least decoding support for them even without such
+                // support. An example of a small decoder for half-precision
+                // floating-point numbers in the C language is shown in Fig. 3.
+                const int half = (v[current_idx + 1] << 8) + v[current_idx + 2];
+                const int exp = (half >> 10) & 0x1f;
+                const int mant = half & 0x3ff;
+                double val;
+                if (exp == 0)
+                {
+                    val = std::ldexp(mant, -24);
+                }
+                else if (exp != 31)
+                {
+                    val = std::ldexp(mant + 1024, exp - 25);
+                }
+                else
+                {
+                    val = mant == 0 ? INFINITY : NAN;
+                }
+                return half & 0x8000 ? -val : val;
+            }
+
+            case 0xfa: // Single-Precision Float (four-byte IEEE 754)
+            {
+                // copy bytes in reverse order into the float variable
+                check_length(v.size(), sizeof(float), 1);
+                float res;
+                for (size_t byte = 0; byte < sizeof(float); ++byte)
+                {
+                    reinterpret_cast<uint8_t*>(&res)[sizeof(float) - byte - 1] = v[current_idx + 1 + byte];
+                }
+                idx += sizeof(float); // skip content bytes
+                return res;
+            }
+
+            case 0xfb: // Double-Precision Float (eight-byte IEEE 754)
+            {
+                check_length(v.size(), sizeof(double), 1);
+                // copy bytes in reverse order into the double variable
+                double res;
+                for (size_t byte = 0; byte < sizeof(double); ++byte)
+                {
+                    reinterpret_cast<uint8_t*>(&res)[sizeof(double) - byte - 1] = v[current_idx + 1 + byte];
+                }
+                idx += sizeof(double); // skip content bytes
+                return res;
+            }
+
+            default: // anything else (0xFF is handled inside the other types)
+            {
+                throw std::invalid_argument("error parsing a CBOR @ " + std::to_string(current_idx) + ": " + std::to_string(static_cast<int>(v[current_idx])));
+            }
+        }
+    }
+
+  public:
+    /*!
+    @brief create a MessagePack serialization of a given JSON value
+
+    Serializes a given JSON value @a j to a byte vector using the MessagePack
+    serialization format. MessagePack is a binary serialization format which
+    aims to be more compact than JSON itself, yet more efficient to parse.
+
+    @param[in] j  JSON value to serialize
+    @return MessagePack serialization as byte vector
+
+    @complexity Linear in the size of the JSON value @a j.
+
+    @liveexample{The example shows the serialization of a JSON value to a byte
+    vector in MessagePack format.,to_msgpack}
+
+    @sa http://msgpack.org
+    @sa @ref from_msgpack(const std::vector<uint8_t>&) for the analogous
+        deserialization
+    @sa @ref to_cbor(const basic_json& for the related CBOR format
+    */
+    static std::vector<uint8_t> to_msgpack(const basic_json& j)
+    {
+        std::vector<uint8_t> result;
+        to_msgpack_internal(j, result);
+        return result;
+    }
+
+    /*!
+    @brief create a JSON value from a byte vector in MessagePack format
+
+    Deserializes a given byte vector @a v to a JSON value using the MessagePack
+    serialization format.
+
+    @param[in] v  a byte vector in MessagePack format
+    @return deserialized JSON value
+
+    @throw std::invalid_argument if unsupported features from MessagePack were
+    used in the given vector @a v or if the input is not valid MessagePack
+    @throw std::out_of_range if the given vector ends prematurely
+
+    @complexity Linear in the size of the byte vector @a v.
+
+    @liveexample{The example shows the deserialization of a byte vector in
+    MessagePack format to a JSON value.,from_msgpack}
+
+    @sa http://msgpack.org
+    @sa @ref to_msgpack(const basic_json&) for the analogous serialization
+    @sa @ref from_cbor(const std::vector<uint8_t>&) for the related CBOR format
+    */
+    static basic_json from_msgpack(const std::vector<uint8_t>& v)
+    {
+        size_t i = 0;
+        return from_msgpack_internal(v, i);
+    }
+
+    /*!
+    @brief create a MessagePack serialization of a given JSON value
+
+    Serializes a given JSON value @a j to a byte vector using the CBOR (Concise
+    Binary Object Representation) serialization format. CBOR is a binary
+    serialization format which aims to be more compact than JSON itself, yet
+    more efficient to parse.
+
+    @param[in] j  JSON value to serialize
+    @return MessagePack serialization as byte vector
+
+    @complexity Linear in the size of the JSON value @a j.
+
+    @liveexample{The example shows the serialization of a JSON value to a byte
+    vector in CBOR format.,to_cbor}
+
+    @sa http://cbor.io
+    @sa @ref from_cbor(const std::vector<uint8_t>&) for the analogous
+        deserialization
+    @sa @ref to_msgpack(const basic_json& for the related MessagePack format
+    */
+    static std::vector<uint8_t> to_cbor(const basic_json& j)
+    {
+        std::vector<uint8_t> result;
+        to_cbor_internal(j, result);
+        return result;
+    }
+
+    /*!
+    @brief create a JSON value from a byte vector in CBOR format
+
+    Deserializes a given byte vector @a v to a JSON value using the CBOR
+    (Concise Binary Object Representation) serialization format.
+
+    @param[in] v  a byte vector in CBOR format
+    @return deserialized JSON value
+
+    @throw std::invalid_argument if unsupported features from CBOR were used in
+    the given vector @a v or if the input is not valid MessagePack
+    @throw std::out_of_range if the given vector ends prematurely
+
+    @complexity Linear in the size of the byte vector @a v.
+
+    @liveexample{The example shows the deserialization of a byte vector in CBOR
+    format to a JSON value.,from_cbor}
+
+    @sa http://cbor.io
+    @sa @ref to_cbor(const basic_json&) for the analogous serialization
+    @sa @ref from_msgpack(const std::vector<uint8_t>&) for the related
+        MessagePack format
+    */
+    static basic_json from_cbor(const std::vector<uint8_t>& v)
+    {
+        size_t i = 0;
+        return from_cbor_internal(v, i);
+    }
+
+    /// @}
+
+  private:
+    ///////////////////////////
+    // convenience functions //
+    ///////////////////////////
+
+    /*!
+    @brief return the type as string
+
+    Returns the type name as string to be used in error messages - usually to
+    indicate that a function was called on a wrong JSON type.
+
+    @return basically a string representation of a the @a m_type member
+
+    @complexity Constant.
+
+    @since version 1.0.0
+    */
+    std::string type_name() const
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+                return "null";
+            case value_t::object:
+                return "object";
+            case value_t::array:
+                return "array";
+            case value_t::string:
+                return "string";
+            case value_t::boolean:
+                return "boolean";
+            case value_t::discarded:
+                return "discarded";
+            default:
+                return "number";
+        }
+    }
+
+    /*!
+    @brief calculates the extra space to escape a JSON string
+
+    @param[in] s  the string to escape
+    @return the number of characters required to escape string @a s
+
+    @complexity Linear in the length of string @a s.
+    */
+    static std::size_t extra_space(const string_t& s) noexcept
+    {
+        return std::accumulate(s.begin(), s.end(), size_t{},
+                               [](size_t res, typename string_t::value_type c)
+        {
+            switch (c)
+            {
+                case '"':
+                case '\\':
+                case '\b':
+                case '\f':
+                case '\n':
+                case '\r':
+                case '\t':
+                {
+                    // from c (1 byte) to \x (2 bytes)
+                    return res + 1;
+                }
+
+                default:
+                {
+                    if (c >= 0x00 and c <= 0x1f)
+                    {
+                        // from c (1 byte) to \uxxxx (6 bytes)
+                        return res + 5;
+                    }
+                    else
+                    {
+                        return res;
+                    }
+                }
+            }
+        });
+    }
+
+    /*!
+    @brief escape a string
+
+    Escape a string by replacing certain special characters by a sequence of
+    an escape character (backslash) and another character and other control
+    characters by a sequence of "\u" followed by a four-digit hex
+    representation.
+
+    @param[in] s  the string to escape
+    @return  the escaped string
+
+    @complexity Linear in the length of string @a s.
+    */
+    static string_t escape_string(const string_t& s)
+    {
+        const auto space = extra_space(s);
+        if (space == 0)
+        {
+            return s;
+        }
+
+        // create a result string of necessary size
+        string_t result(s.size() + space, '\\');
+        std::size_t pos = 0;
+
+        for (const auto& c : s)
+        {
+            switch (c)
+            {
+                // quotation mark (0x22)
+                case '"':
+                {
+                    result[pos + 1] = '"';
+                    pos += 2;
+                    break;
+                }
+
+                // reverse solidus (0x5c)
+                case '\\':
+                {
+                    // nothing to change
+                    pos += 2;
+                    break;
+                }
+
+                // backspace (0x08)
+                case '\b':
+                {
+                    result[pos + 1] = 'b';
+                    pos += 2;
+                    break;
+                }
+
+                // formfeed (0x0c)
+                case '\f':
+                {
+                    result[pos + 1] = 'f';
+                    pos += 2;
+                    break;
+                }
+
+                // newline (0x0a)
+                case '\n':
+                {
+                    result[pos + 1] = 'n';
+                    pos += 2;
+                    break;
+                }
+
+                // carriage return (0x0d)
+                case '\r':
+                {
                     result[pos + 1] = 'r';
                     pos += 2;
                     break;
@@ -6694,10 +8279,10 @@ class basic_json
 
   public:
     /*!
-    @brief a const random access iterator for the @ref basic_json class
+    @brief a template for a random access iterator for the @ref basic_json class
 
-    This class implements a const iterator for the @ref basic_json class. From
-    this class, the @ref iterator class is derived.
+    This class implements a both iterators (iterator and const_iterator) for the
+    @ref basic_json class.
 
     @note An iterator is called *initialized* when a pointer to a JSON value
           has been set (e.g., by a constructor or a copy assignment). If the
@@ -6710,27 +8295,37 @@ class basic_json
       The iterator that can be moved to point (forward and backward) to any
       element in constant time.
 
-    @since version 1.0.0
+    @since version 1.0.0, simplified in version 2.0.9
     */
-    class const_iterator : public std::iterator<std::random_access_iterator_tag, const basic_json>
+    template<typename U>
+    class iter_impl : public std::iterator<std::random_access_iterator_tag, U>
     {
         /// allow basic_json to access private members
         friend class basic_json;
 
+        // make sure U is basic_json or const basic_json
+        static_assert(std::is_same<U, basic_json>::value
+                      or std::is_same<U, const basic_json>::value,
+                      "iter_impl only accepts (const) basic_json");
+
       public:
         /// the type of the values when the iterator is dereferenced
         using value_type = typename basic_json::value_type;
         /// a type to represent differences between iterators
         using difference_type = typename basic_json::difference_type;
         /// defines a pointer to the type iterated over (value_type)
-        using pointer = typename basic_json::const_pointer;
+        using pointer = typename std::conditional<std::is_const<U>::value,
+              typename basic_json::const_pointer,
+              typename basic_json::pointer>::type;
         /// defines a reference to the type iterated over (value_type)
-        using reference = typename basic_json::const_reference;
+        using reference = typename std::conditional<std::is_const<U>::value,
+              typename basic_json::const_reference,
+              typename basic_json::reference>::type;
         /// the category of the iterator
         using iterator_category = std::bidirectional_iterator_tag;
 
         /// default constructor
-        const_iterator() = default;
+        iter_impl() = default;
 
         /*!
         @brief constructor for a given JSON instance
@@ -6738,7 +8333,7 @@ class basic_json
         @pre object != nullptr
         @post The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        explicit const_iterator(pointer object) noexcept
+        explicit iter_impl(pointer object) noexcept
             : m_object(object)
         {
             assert(m_object != nullptr);
@@ -6765,37 +8360,25 @@ class basic_json
             }
         }
 
-        /*!
-        @brief copy constructor given a non-const iterator
-        @param[in] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
+        /*
+        Use operator `const_iterator` instead of `const_iterator(const iterator&
+        other) noexcept` to avoid two class definitions for @ref iterator and
+        @ref const_iterator.
+
+        This function is only called if this class is an @ref iterator. If this
+        class is a @ref const_iterator this function is not called.
         */
-        explicit const_iterator(const iterator& other) noexcept
-            : m_object(other.m_object)
+        operator const_iterator() const
         {
-            if (m_object != nullptr)
-            {
-                switch (m_object->m_type)
-                {
-                    case basic_json::value_t::object:
-                    {
-                        m_it.object_iterator = other.m_it.object_iterator;
-                        break;
-                    }
-
-                    case basic_json::value_t::array:
-                    {
-                        m_it.array_iterator = other.m_it.array_iterator;
-                        break;
-                    }
+            const_iterator ret;
 
-                    default:
-                    {
-                        m_it.primitive_iterator = other.m_it.primitive_iterator;
-                        break;
-                    }
-                }
+            if (m_object)
+            {
+                ret.m_object = m_object;
+                ret.m_it = m_it;
             }
+
+            return ret;
         }
 
         /*!
@@ -6803,7 +8386,7 @@ class basic_json
         @param[in] other  iterator to copy from
         @note It is not checked whether @a other is initialized.
         */
-        const_iterator(const const_iterator& other) noexcept
+        iter_impl(const iter_impl& other) noexcept
             : m_object(other.m_object), m_it(other.m_it)
         {}
 
@@ -6812,7 +8395,7 @@ class basic_json
         @param[in,out] other  iterator to copy from
         @note It is not checked whether @a other is initialized.
         */
-        const_iterator& operator=(const_iterator other) noexcept(
+        iter_impl& operator=(iter_impl other) noexcept(
             std::is_nothrow_move_constructible<pointer>::value and
             std::is_nothrow_move_assignable<pointer>::value and
             std::is_nothrow_move_constructible<internal_iterator>::value and
@@ -6974,7 +8557,7 @@ class basic_json
         @brief post-increment (it++)
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        const_iterator operator++(int)
+        iter_impl operator++(int)
         {
             auto result = *this;
             ++(*this);
@@ -6985,7 +8568,7 @@ class basic_json
         @brief pre-increment (++it)
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        const_iterator& operator++()
+        iter_impl& operator++()
         {
             assert(m_object != nullptr);
 
@@ -7017,7 +8600,7 @@ class basic_json
         @brief post-decrement (it--)
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        const_iterator operator--(int)
+        iter_impl operator--(int)
         {
             auto result = *this;
             --(*this);
@@ -7028,7 +8611,7 @@ class basic_json
         @brief pre-decrement (--it)
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        const_iterator& operator--()
+        iter_impl& operator--()
         {
             assert(m_object != nullptr);
 
@@ -7060,7 +8643,7 @@ class basic_json
         @brief  comparison: equal
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        bool operator==(const const_iterator& other) const
+        bool operator==(const iter_impl& other) const
         {
             // if objects are not the same, the comparison is undefined
             if (m_object != other.m_object)
@@ -7093,7 +8676,7 @@ class basic_json
         @brief  comparison: not equal
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        bool operator!=(const const_iterator& other) const
+        bool operator!=(const iter_impl& other) const
         {
             return not operator==(other);
         }
@@ -7102,7 +8685,7 @@ class basic_json
         @brief  comparison: smaller
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        bool operator<(const const_iterator& other) const
+        bool operator<(const iter_impl& other) const
         {
             // if objects are not the same, the comparison is undefined
             if (m_object != other.m_object)
@@ -7135,7 +8718,7 @@ class basic_json
         @brief  comparison: less than or equal
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        bool operator<=(const const_iterator& other) const
+        bool operator<=(const iter_impl& other) const
         {
             return not other.operator < (*this);
         }
@@ -7144,7 +8727,7 @@ class basic_json
         @brief  comparison: greater than
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        bool operator>(const const_iterator& other) const
+        bool operator>(const iter_impl& other) const
         {
             return not operator<=(other);
         }
@@ -7153,7 +8736,7 @@ class basic_json
         @brief  comparison: greater than or equal
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        bool operator>=(const const_iterator& other) const
+        bool operator>=(const iter_impl& other) const
         {
             return not operator<(other);
         }
@@ -7162,7 +8745,7 @@ class basic_json
         @brief  add to iterator
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        const_iterator& operator+=(difference_type i)
+        iter_impl& operator+=(difference_type i)
         {
             assert(m_object != nullptr);
 
@@ -7193,7 +8776,7 @@ class basic_json
         @brief  subtract from iterator
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        const_iterator& operator-=(difference_type i)
+        iter_impl& operator-=(difference_type i)
         {
             return operator+=(-i);
         }
@@ -7202,7 +8785,7 @@ class basic_json
         @brief  add to iterator
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        const_iterator operator+(difference_type i)
+        iter_impl operator+(difference_type i)
         {
             auto result = *this;
             result += i;
@@ -7213,7 +8796,7 @@ class basic_json
         @brief  subtract from iterator
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        const_iterator operator-(difference_type i)
+        iter_impl operator-(difference_type i)
         {
             auto result = *this;
             result -= i;
@@ -7224,7 +8807,7 @@ class basic_json
         @brief  return difference
         @pre The iterator is initialized; i.e. `m_object != nullptr`.
         */
-        difference_type operator-(const const_iterator& other) const
+        difference_type operator-(const iter_impl& other) const
         {
             assert(m_object != nullptr);
 
@@ -7320,141 +8903,6 @@ class basic_json
         internal_iterator m_it = internal_iterator();
     };
 
-    /*!
-    @brief a mutable random access iterator for the @ref basic_json class
-
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
-    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
-      It is possible to write to the pointed-to element.
-
-    @since version 1.0.0
-    */
-    class iterator : public const_iterator
-    {
-      public:
-        using base_iterator = const_iterator;
-        using pointer = typename basic_json::pointer;
-        using reference = typename basic_json::reference;
-
-        /// default constructor
-        iterator() = default;
-
-        /// constructor for a given JSON instance
-        explicit iterator(pointer object) noexcept
-            : base_iterator(object)
-        {}
-
-        /// copy constructor
-        iterator(const iterator& other) noexcept
-            : base_iterator(other)
-        {}
-
-        /// copy assignment
-        iterator& operator=(iterator other) noexcept(
-            std::is_nothrow_move_constructible<pointer>::value and
-            std::is_nothrow_move_assignable<pointer>::value and
-            std::is_nothrow_move_constructible<internal_iterator>::value and
-            std::is_nothrow_move_assignable<internal_iterator>::value
-        )
-        {
-            base_iterator::operator=(other);
-            return *this;
-        }
-
-        /// return a reference to the value pointed to by the iterator
-        reference operator*() const
-        {
-            return const_cast<reference>(base_iterator::operator*());
-        }
-
-        /// dereference the iterator
-        pointer operator->() const
-        {
-            return const_cast<pointer>(base_iterator::operator->());
-        }
-
-        /// post-increment (it++)
-        iterator operator++(int)
-        {
-            iterator result = *this;
-            base_iterator::operator++();
-            return result;
-        }
-
-        /// pre-increment (++it)
-        iterator& operator++()
-        {
-            base_iterator::operator++();
-            return *this;
-        }
-
-        /// post-decrement (it--)
-        iterator operator--(int)
-        {
-            iterator result = *this;
-            base_iterator::operator--();
-            return result;
-        }
-
-        /// pre-decrement (--it)
-        iterator& operator--()
-        {
-            base_iterator::operator--();
-            return *this;
-        }
-
-        /// add to iterator
-        iterator& operator+=(difference_type i)
-        {
-            base_iterator::operator+=(i);
-            return *this;
-        }
-
-        /// subtract from iterator
-        iterator& operator-=(difference_type i)
-        {
-            base_iterator::operator-=(i);
-            return *this;
-        }
-
-        /// add to iterator
-        iterator operator+(difference_type i)
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
-
-        /// subtract from iterator
-        iterator operator-(difference_type i)
-        {
-            auto result = *this;
-            result -= i;
-            return result;
-        }
-
-        /// return difference
-        difference_type operator-(const iterator& other) const
-        {
-            return base_iterator::operator-(other);
-        }
-
-        /// access to successor
-        reference operator[](difference_type n) const
-        {
-            return const_cast<reference>(base_iterator::operator[](n));
-        }
-
-        /// return the value of an iterator
-        reference value() const
-        {
-            return const_cast<reference>(base_iterator::value());
-        }
-    };
-
     /*!
     @brief a template for a reverse iterator class
 
@@ -7618,6 +9066,12 @@ class basic_json
         explicit lexer(std::istream& s)
             : m_stream(&s), m_line_buffer()
         {
+            // immediately abort if stream is erroneous
+            if (s.fail())
+            {
+                throw std::invalid_argument("stream error");
+            }
+
             // fill buffer
             fill_line_buffer();
 
@@ -8740,8 +10194,22 @@ basic_json_parser_66:
         */
         void fill_line_buffer(size_t n = 0)
         {
+            // if line buffer is used, m_content points to its data
+            assert(m_line_buffer.empty()
+                   or m_content == reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()));
+
+            // if line buffer is used, m_limit is set past the end of its data
+            assert(m_line_buffer.empty()
+                   or m_limit == m_content + m_line_buffer.size());
+
+            // pointer relationships
+            assert(m_content <= m_start);
+            assert(m_start <= m_cursor);
+            assert(m_cursor <= m_limit);
+            assert(m_marker == nullptr or m_marker  <= m_limit);
+
             // number of processed characters (p)
-            const auto offset_start = m_start - m_content;
+            const size_t num_processed_chars = static_cast<size_t>(m_start - m_content);
             // offset for m_marker wrt. to m_start
             const auto offset_marker = (m_marker == nullptr) ? 0 : m_marker - m_start;
             // number of unprocessed characters (u)
@@ -8750,35 +10218,34 @@ basic_json_parser_66:
             // no stream is used or end of file is reached
             if (m_stream == nullptr or m_stream->eof())
             {
-                // skip this part if we are already using the line buffer
-                if (m_start != reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()))
-                {
-                    // copy unprocessed characters to line buffer
-                    m_line_buffer.clear();
-                    for (m_cursor = m_start; m_cursor != m_limit; ++m_cursor)
-                    {
-                        m_line_buffer.append(1, static_cast<const char>(*m_cursor));
-                    }
-                }
+                // m_start may or may not be pointing into m_line_buffer at
+                // this point. We trust the standand library to do the right
+                // thing. See http://stackoverflow.com/q/28142011/266378
+                m_line_buffer.assign(m_start, m_limit);
 
                 // append n characters to make sure that there is sufficient
                 // space between m_cursor and m_limit
                 m_line_buffer.append(1, '\x00');
-                m_line_buffer.append(n - 1, '\x01');
+                if (n > 0)
+                {
+                    m_line_buffer.append(n - 1, '\x01');
+                }
             }
             else
             {
                 // delete processed characters from line buffer
-                m_line_buffer.erase(0, static_cast<size_t>(offset_start));
+                m_line_buffer.erase(0, num_processed_chars);
                 // read next line from input stream
-                std::string line;
-                std::getline(*m_stream, line, '\n');
+                m_line_buffer_tmp.clear();
+                std::getline(*m_stream, m_line_buffer_tmp, '\n');
+
                 // add line with newline symbol to the line buffer
-                m_line_buffer += line + "\n";
+                m_line_buffer += m_line_buffer_tmp;
+                m_line_buffer.push_back('\n');
             }
 
             // set pointers
-            m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.c_str());
+            m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.data());
             assert(m_content != nullptr);
             m_start  = m_content;
             m_marker = m_start + offset_marker;
@@ -8861,9 +10328,20 @@ basic_json_parser_66:
             // iterate the result between the quotes
             for (const lexer_char_t* i = m_start + 1; i < m_cursor - 1; ++i)
             {
-                // process escaped characters
-                if (*i == '\\')
+                // find next escape character
+                auto e = std::find(i, m_cursor - 1, '\\');
+                if (e != i)
+                {
+                    // see https://github.com/nlohmann/json/issues/365#issuecomment-262874705
+                    for (auto k = i; k < e; k++)
+                    {
+                        result.push_back(static_cast<typename string_t::value_type>(*k));
+                    }
+                    i = e - 1; // -1 because of ++i
+                }
+                else
                 {
+                    // processing escaped character
                     // read next character
                     ++i;
 
@@ -8950,12 +10428,6 @@ basic_json_parser_66:
                         }
                     }
                 }
-                else
-                {
-                    // all other characters are just copied to the end of the
-                    // string
-                    result.append(1, static_cast<typename string_t::value_type>(*i));
-                }
             }
 
             return result;
@@ -8969,8 +10441,6 @@ basic_json_parser_66:
         supplied via the first parameter.  Set this to @a
         static_cast<number_float_t*>(nullptr).
 
-        @param[in] type  the @ref number_float_t in use
-
         @param[in,out] endptr recieves a pointer to the first character after
         the number
 
@@ -8989,8 +10459,6 @@ basic_json_parser_66:
         supplied via the first parameter.  Set this to @a
         static_cast<number_float_t*>(nullptr).
 
-        @param[in] type  the @ref number_float_t in use
-
         @param[in,out] endptr  recieves a pointer to the first character after
         the number
 
@@ -9009,8 +10477,6 @@ basic_json_parser_66:
         supplied via the first parameter.  Set this to @a
         static_cast<number_float_t*>(nullptr).
 
-        @param[in] type  the @ref number_float_t in use
-
         @param[in,out] endptr  recieves a pointer to the first character after
         the number
 
@@ -9091,19 +10557,19 @@ basic_json_parser_66:
                 // skip if definitely not an integer
                 if (type != value_t::number_float)
                 {
-                    // multiply last value by ten and add the new digit
-                    auto temp = value * 10 + *curptr - '0';
+                    auto digit = static_cast<number_unsigned_t>(*curptr - '0');
 
-                    // test for overflow
-                    if (temp < value || temp > max)
+                    // overflow if value * 10 + digit > max, move terms around
+                    // to avoid overflow in intermediate values
+                    if (value > (max - digit) / 10)
                     {
                         // overflow
                         type = value_t::number_float;
                     }
                     else
                     {
-                        // no overflow - save it
-                        value = temp;
+                        // no overflow
+                        value = value * 10 + digit;
                     }
                 }
             }
@@ -9115,7 +10581,22 @@ basic_json_parser_66:
             }
             else if (type == value_t::number_integer)
             {
-                result.m_value.number_integer = -static_cast<number_integer_t>(value);
+                // invariant: if we parsed a '-', the absolute value is between
+                // 0 (we allow -0) and max == -INT64_MIN
+                assert(value >= 0);
+                assert(value <= max);
+
+                if (value == max)
+                {
+                    // we cannot simply negate value (== max == -INT64_MIN),
+                    // see https://github.com/nlohmann/json/issues/389
+                    result.m_value.number_integer = static_cast<number_integer_t>(INT64_MIN);
+                }
+                else
+                {
+                    // all other values can be negated safely
+                    result.m_value.number_integer = -static_cast<number_integer_t>(value);
+                }
             }
             else
             {
@@ -9139,6 +10620,8 @@ basic_json_parser_66:
         std::istream* m_stream = nullptr;
         /// line buffer buffer for m_stream
         string_t m_line_buffer {};
+        /// used for filling m_line_buffer
+        string_t m_line_buffer_tmp {};
         /// the buffer pointer
         const lexer_char_t* m_content = nullptr;
         /// pointer to the beginning of the current symbol
@@ -9896,13 +11379,11 @@ basic_json_parser_66:
         /*!
         @brief replace all occurrences of a substring by another string
 
-        @param[in,out] s  the string to manipulate
+        @param[in,out] s  the string to manipulate; changed so that all
+                          occurrences of @a f are replaced with @a t
         @param[in]     f  the substring to replace with @a t
         @param[in]     t  the string to replace @a f
 
-        @return The string @a s where all occurrences of @a f are replaced
-                with @a t.
-
         @pre The search string @a f must not be empty.
 
         @since version 2.0.0
-- 
cgit v1.2.3


From 9e80db0fd169de19d5d343e8b6998c8ace4aeb22 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Thu, 27 Apr 2017 00:59:36 -0700
Subject: Cleanup, fix a valgrind error, stack use reduction.

---
 controller/EmbeddedNetworkController.cpp |  134 +-
 controller/EmbeddedNetworkController.hpp |    3 +-
 controller/JSONDB.cpp                    |   57 +-
 controller/JSONDB.hpp                    |   55 +-
 ext/json/LICENSE.MIT                     |   17 +-
 ext/json/README.md                       |  420 +-
 ext/json/json.hpp                        | 6976 +++++++++++++++++++-----------
 make-linux.mk                            |    9 +-
 node/CertificateOfOwnership.hpp          |    2 +
 root-watcher/schema.sql                  |    3 +-
 selftest.cpp                             |   47 -
 11 files changed, 4910 insertions(+), 2813 deletions(-)

(limited to 'ext/json/json.hpp')

diff --git a/controller/EmbeddedNetworkController.cpp b/controller/EmbeddedNetworkController.cpp
index be53f2b8..a41a4a94 100644
--- a/controller/EmbeddedNetworkController.cpp
+++ b/controller/EmbeddedNetworkController.cpp
@@ -1,6 +1,6 @@
 /*
  * ZeroTier One - Network Virtualization Everywhere
- * Copyright (C) 2011-2015  ZeroTier, Inc.
+ * Copyright (C) 2011-2015  ZeroTier, Inc->
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -30,9 +30,9 @@
 #include <algorithm>
 #include <utility>
 #include <stdexcept>
-#include <set>
 #include <map>
 #include <thread>
+#include <memory>
 
 #include "../include/ZeroTierOne.h"
 #include "../node/Constants.hpp"
@@ -1017,7 +1017,7 @@ unsigned int EmbeddedNetworkController::handleControlPlaneHttpPOST(
 				network["id"] = nwids;
 				network["nwid"] = nwids; // legacy
 
-				if (network != origNetwork) {
+				if (true) {
 					json &revj = network["revision"];
 					network["revision"] = (revj.is_number() ? ((uint64_t)revj + 1ULL) : 1ULL);
 					network["lastModified"] = now;
@@ -1235,8 +1235,9 @@ void EmbeddedNetworkController::_request(
 	}
 
 	// These are always the same, but make sure they are set
-	member["id"] = identity.address().toString();
-	member["address"] = member["id"];
+	const std::string addrs(identity.address().toString());
+	member["id"] = addrs;
+	member["address"] = addrs;
 	member["nwid"] = nwids;
 
 	// Determine whether and how member is authorized
@@ -1356,8 +1357,6 @@ void EmbeddedNetworkController::_request(
 	// If we made it this far, they are authorized.
 	// -------------------------------------------------------------------------
 
-	NetworkConfig nc;
-
 	uint64_t credentialtmd = ZT_NETWORKCONFIG_DEFAULT_CREDENTIAL_TIME_MAX_MAX_DELTA;
 	if (now > ns.mostRecentDeauthTime) {
 		// If we recently de-authorized a member, shrink credential TTL/max delta to
@@ -1371,19 +1370,21 @@ void EmbeddedNetworkController::_request(
 		}
 	}
 
-	nc.networkId = nwid;
-	nc.type = OSUtils::jsonBool(network["private"],true) ? ZT_NETWORK_TYPE_PRIVATE : ZT_NETWORK_TYPE_PUBLIC;
-	nc.timestamp = now;
-	nc.credentialTimeMaxDelta = credentialtmd;
-	nc.revision = OSUtils::jsonInt(network["revision"],0ULL);
-	nc.issuedTo = identity.address();
-	if (OSUtils::jsonBool(network["enableBroadcast"],true)) nc.flags |= ZT_NETWORKCONFIG_FLAG_ENABLE_BROADCAST;
-	if (OSUtils::jsonBool(network["allowPassiveBridging"],false)) nc.flags |= ZT_NETWORKCONFIG_FLAG_ALLOW_PASSIVE_BRIDGING;
-	Utils::scopy(nc.name,sizeof(nc.name),OSUtils::jsonString(network["name"],"").c_str());
-	nc.multicastLimit = (unsigned int)OSUtils::jsonInt(network["multicastLimit"],32ULL);
+	std::auto_ptr<NetworkConfig> nc(new NetworkConfig());
+
+	nc->networkId = nwid;
+	nc->type = OSUtils::jsonBool(network["private"],true) ? ZT_NETWORK_TYPE_PRIVATE : ZT_NETWORK_TYPE_PUBLIC;
+	nc->timestamp = now;
+	nc->credentialTimeMaxDelta = credentialtmd;
+	nc->revision = OSUtils::jsonInt(network["revision"],0ULL);
+	nc->issuedTo = identity.address();
+	if (OSUtils::jsonBool(network["enableBroadcast"],true)) nc->flags |= ZT_NETWORKCONFIG_FLAG_ENABLE_BROADCAST;
+	if (OSUtils::jsonBool(network["allowPassiveBridging"],false)) nc->flags |= ZT_NETWORKCONFIG_FLAG_ALLOW_PASSIVE_BRIDGING;
+	Utils::scopy(nc->name,sizeof(nc->name),OSUtils::jsonString(network["name"],"").c_str());
+	nc->multicastLimit = (unsigned int)OSUtils::jsonInt(network["multicastLimit"],32ULL);
 
 	for(std::vector<Address>::const_iterator ab(ns.activeBridges.begin());ab!=ns.activeBridges.end();++ab)
-		nc.addSpecialist(*ab,ZT_NETWORKCONFIG_SPECIALIST_TYPE_ACTIVE_BRIDGE);
+		nc->addSpecialist(*ab,ZT_NETWORKCONFIG_SPECIALIST_TYPE_ACTIVE_BRIDGE);
 
 	json &v4AssignMode = network["v4AssignMode"];
 	json &v6AssignMode = network["v6AssignMode"];
@@ -1399,15 +1400,15 @@ void EmbeddedNetworkController::_request(
 		// Old versions with no rules engine support get an allow everything rule.
 		// Since rules are enforced bidirectionally, newer versions *will* still
 		// enforce rules on the inbound side.
-		nc.ruleCount = 1;
-		nc.rules[0].t = ZT_NETWORK_RULE_ACTION_ACCEPT;
+		nc->ruleCount = 1;
+		nc->rules[0].t = ZT_NETWORK_RULE_ACTION_ACCEPT;
 	} else {
 		if (rules.is_array()) {
 			for(unsigned long i=0;i<rules.size();++i) {
-				if (nc.ruleCount >= ZT_MAX_NETWORK_RULES)
+				if (nc->ruleCount >= ZT_MAX_NETWORK_RULES)
 					break;
-				if (_parseRule(rules[i],nc.rules[nc.ruleCount]))
-					++nc.ruleCount;
+				if (_parseRule(rules[i],nc->rules[nc->ruleCount]))
+					++nc->ruleCount;
 			}
 		}
 
@@ -1451,10 +1452,10 @@ void EmbeddedNetworkController::_request(
 								++caprc;
 						}
 					}
-					nc.capabilities[nc.capabilityCount] = Capability((uint32_t)capId,nwid,now,1,capr,caprc);
-					if (nc.capabilities[nc.capabilityCount].sign(_signingId,identity.address()))
-						++nc.capabilityCount;
-					if (nc.capabilityCount >= ZT_MAX_NETWORK_CAPABILITIES)
+					nc->capabilities[nc->capabilityCount] = Capability((uint32_t)capId,nwid,now,1,capr,caprc);
+					if (nc->capabilities[nc->capabilityCount].sign(_signingId,identity.address()))
+						++nc->capabilityCount;
+					if (nc->capabilityCount >= ZT_MAX_NETWORK_CAPABILITIES)
 						break;
 				}
 			}
@@ -1485,17 +1486,17 @@ void EmbeddedNetworkController::_request(
 			}
 		}
 		for(std::map< uint32_t,uint32_t >::const_iterator t(memberTagsById.begin());t!=memberTagsById.end();++t) {
-			if (nc.tagCount >= ZT_MAX_NETWORK_TAGS)
+			if (nc->tagCount >= ZT_MAX_NETWORK_TAGS)
 				break;
-			nc.tags[nc.tagCount] = Tag(nwid,now,identity.address(),t->first,t->second);
-			if (nc.tags[nc.tagCount].sign(_signingId))
-				++nc.tagCount;
+			nc->tags[nc->tagCount] = Tag(nwid,now,identity.address(),t->first,t->second);
+			if (nc->tags[nc->tagCount].sign(_signingId))
+				++nc->tagCount;
 		}
 	}
 
 	if (routes.is_array()) {
 		for(unsigned long i=0;i<routes.size();++i) {
-			if (nc.routeCount >= ZT_MAX_NETWORK_ROUTES)
+			if (nc->routeCount >= ZT_MAX_NETWORK_ROUTES)
 				break;
 			json &route = routes[i];
 			json &target = route["target"];
@@ -1505,11 +1506,11 @@ void EmbeddedNetworkController::_request(
 				InetAddress v;
 				if (via.is_string()) v.fromString(via.get<std::string>());
 				if ((t.ss_family == AF_INET)||(t.ss_family == AF_INET6)) {
-					ZT_VirtualNetworkRoute *r = &(nc.routes[nc.routeCount]);
+					ZT_VirtualNetworkRoute *r = &(nc->routes[nc->routeCount]);
 					*(reinterpret_cast<InetAddress *>(&(r->target))) = t;
 					if (v.ss_family == t.ss_family)
 						*(reinterpret_cast<InetAddress *>(&(r->via))) = v;
-					++nc.routeCount;
+					++nc->routeCount;
 				}
 			}
 		}
@@ -1518,13 +1519,13 @@ void EmbeddedNetworkController::_request(
 	const bool noAutoAssignIps = OSUtils::jsonBool(member["noAutoAssignIps"],false);
 
 	if ((v6AssignMode.is_object())&&(!noAutoAssignIps)) {
-		if ((OSUtils::jsonBool(v6AssignMode["rfc4193"],false))&&(nc.staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES)) {
-			nc.staticIps[nc.staticIpCount++] = InetAddress::makeIpv6rfc4193(nwid,identity.address().toInt());
-			nc.flags |= ZT_NETWORKCONFIG_FLAG_ENABLE_IPV6_NDP_EMULATION;
+		if ((OSUtils::jsonBool(v6AssignMode["rfc4193"],false))&&(nc->staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES)) {
+			nc->staticIps[nc->staticIpCount++] = InetAddress::makeIpv6rfc4193(nwid,identity.address().toInt());
+			nc->flags |= ZT_NETWORKCONFIG_FLAG_ENABLE_IPV6_NDP_EMULATION;
 		}
-		if ((OSUtils::jsonBool(v6AssignMode["6plane"],false))&&(nc.staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES)) {
-			nc.staticIps[nc.staticIpCount++] = InetAddress::makeIpv66plane(nwid,identity.address().toInt());
-			nc.flags |= ZT_NETWORKCONFIG_FLAG_ENABLE_IPV6_NDP_EMULATION;
+		if ((OSUtils::jsonBool(v6AssignMode["6plane"],false))&&(nc->staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES)) {
+			nc->staticIps[nc->staticIpCount++] = InetAddress::makeIpv66plane(nwid,identity.address().toInt());
+			nc->flags |= ZT_NETWORKCONFIG_FLAG_ENABLE_IPV6_NDP_EMULATION;
 		}
 	}
 
@@ -1542,15 +1543,15 @@ void EmbeddedNetworkController::_request(
 			// this route, ignoring the netmask bits field of the assigned IP itself. Using that was worthless and a source
 			// of user error / poor UX.
 			int routedNetmaskBits = 0;
-			for(unsigned int rk=0;rk<nc.routeCount;++rk) {
-				if ( (!nc.routes[rk].via.ss_family) && (reinterpret_cast<const InetAddress *>(&(nc.routes[rk].target))->containsAddress(ip)) )
-					routedNetmaskBits = reinterpret_cast<const InetAddress *>(&(nc.routes[rk].target))->netmaskBits();
+			for(unsigned int rk=0;rk<nc->routeCount;++rk) {
+				if ( (!nc->routes[rk].via.ss_family) && (reinterpret_cast<const InetAddress *>(&(nc->routes[rk].target))->containsAddress(ip)) )
+					routedNetmaskBits = reinterpret_cast<const InetAddress *>(&(nc->routes[rk].target))->netmaskBits();
 			}
 
 			if (routedNetmaskBits > 0) {
-				if (nc.staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES) {
+				if (nc->staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES) {
 					ip.setPort(routedNetmaskBits);
-					nc.staticIps[nc.staticIpCount++] = ip;
+					nc->staticIps[nc->staticIpCount++] = ip;
 				}
 				if (ip.ss_family == AF_INET)
 					haveManagedIpv4AutoAssignment = true;
@@ -1601,9 +1602,9 @@ void EmbeddedNetworkController::_request(
 
 						// Check if this IP is within a local-to-Ethernet routed network
 						int routedNetmaskBits = 0;
-						for(unsigned int rk=0;rk<nc.routeCount;++rk) {
-							if ( (!nc.routes[rk].via.ss_family) && (nc.routes[rk].target.ss_family == AF_INET6) && (reinterpret_cast<const InetAddress *>(&(nc.routes[rk].target))->containsAddress(ip6)) )
-								routedNetmaskBits = reinterpret_cast<const InetAddress *>(&(nc.routes[rk].target))->netmaskBits();
+						for(unsigned int rk=0;rk<nc->routeCount;++rk) {
+							if ( (!nc->routes[rk].via.ss_family) && (nc->routes[rk].target.ss_family == AF_INET6) && (reinterpret_cast<const InetAddress *>(&(nc->routes[rk].target))->containsAddress(ip6)) )
+								routedNetmaskBits = reinterpret_cast<const InetAddress *>(&(nc->routes[rk].target))->netmaskBits();
 						}
 
 						// If it's routed, then try to claim and assign it and if successful end loop
@@ -1611,8 +1612,8 @@ void EmbeddedNetworkController::_request(
 							ipAssignments.push_back(ip6.toIpString());
 							member["ipAssignments"] = ipAssignments;
 							ip6.setPort((unsigned int)routedNetmaskBits);
-							if (nc.staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES)
-								nc.staticIps[nc.staticIpCount++] = ip6;
+							if (nc->staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES)
+								nc->staticIps[nc->staticIpCount++] = ip6;
 							haveManagedIpv6AutoAssignment = true;
 							break;
 						}
@@ -1646,10 +1647,10 @@ void EmbeddedNetworkController::_request(
 
 						// Check if this IP is within a local-to-Ethernet routed network
 						int routedNetmaskBits = -1;
-						for(unsigned int rk=0;rk<nc.routeCount;++rk) {
-							if (nc.routes[rk].target.ss_family == AF_INET) {
-								uint32_t targetIp = Utils::ntoh((uint32_t)(reinterpret_cast<const struct sockaddr_in *>(&(nc.routes[rk].target))->sin_addr.s_addr));
-								int targetBits = Utils::ntoh((uint16_t)(reinterpret_cast<const struct sockaddr_in *>(&(nc.routes[rk].target))->sin_port));
+						for(unsigned int rk=0;rk<nc->routeCount;++rk) {
+							if (nc->routes[rk].target.ss_family == AF_INET) {
+								uint32_t targetIp = Utils::ntoh((uint32_t)(reinterpret_cast<const struct sockaddr_in *>(&(nc->routes[rk].target))->sin_addr.s_addr));
+								int targetBits = Utils::ntoh((uint16_t)(reinterpret_cast<const struct sockaddr_in *>(&(nc->routes[rk].target))->sin_port));
 								if ((ip & (0xffffffff << (32 - targetBits))) == targetIp) {
 									routedNetmaskBits = targetBits;
 									break;
@@ -1662,8 +1663,8 @@ void EmbeddedNetworkController::_request(
 						if ( (routedNetmaskBits > 0) && (!std::binary_search(ns.allocatedIps.begin(),ns.allocatedIps.end(),ip4)) ) {
 							ipAssignments.push_back(ip4.toIpString());
 							member["ipAssignments"] = ipAssignments;
-							if (nc.staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES) {
-								struct sockaddr_in *const v4ip = reinterpret_cast<struct sockaddr_in *>(&(nc.staticIps[nc.staticIpCount++]));
+							if (nc->staticIpCount < ZT_MAX_ZT_ASSIGNED_ADDRESSES) {
+								struct sockaddr_in *const v4ip = reinterpret_cast<struct sockaddr_in *>(&(nc->staticIps[nc->staticIpCount++]));
 								v4ip->sin_family = AF_INET;
 								v4ip->sin_port = Utils::hton((uint16_t)routedNetmaskBits);
 								v4ip->sin_addr.s_addr = Utils::hton(ip);
@@ -1678,17 +1679,17 @@ void EmbeddedNetworkController::_request(
 	}
 
 	// Issue a certificate of ownership for all static IPs
-	if (nc.staticIpCount) {
-		nc.certificatesOfOwnership[0] = CertificateOfOwnership(nwid,now,identity.address(),1);
-		for(unsigned int i=0;i<nc.staticIpCount;++i)
-			nc.certificatesOfOwnership[0].addThing(nc.staticIps[i]);
-		nc.certificatesOfOwnership[0].sign(_signingId);
-		nc.certificateOfOwnershipCount = 1;
+	if (nc->staticIpCount) {
+		nc->certificatesOfOwnership[0] = CertificateOfOwnership(nwid,now,identity.address(),1);
+		for(unsigned int i=0;i<nc->staticIpCount;++i)
+			nc->certificatesOfOwnership[0].addThing(nc->staticIps[i]);
+		nc->certificatesOfOwnership[0].sign(_signingId);
+		nc->certificateOfOwnershipCount = 1;
 	}
 
 	CertificateOfMembership com(now,credentialtmd,nwid,identity.address());
 	if (com.sign(_signingId)) {
-		nc.com = com;
+		nc->com = com;
 	} else {
 		_sender->ncSendError(nwid,requestPacketId,identity.address(),NetworkController::NC_ERROR_INTERNAL_SERVER_ERROR);
 		return;
@@ -1699,7 +1700,7 @@ void EmbeddedNetworkController::_request(
 		_db.saveNetworkMember(nwid,identity.address().toInt(),member);
 	}
 
-	_sender->ncSendConfig(nwid,requestPacketId,identity.address(),nc,metaData.getUI(ZT_NETWORKCONFIG_REQUEST_METADATA_KEY_VERSION,0) < 6);
+	_sender->ncSendConfig(nwid,requestPacketId,identity.address(),*(nc.get()),metaData.getUI(ZT_NETWORKCONFIG_REQUEST_METADATA_KEY_VERSION,0) < 6);
 }
 
 void EmbeddedNetworkController::_pushMemberUpdate(uint64_t now,uint64_t nwid,const nlohmann::json &member)
@@ -1716,11 +1717,10 @@ void EmbeddedNetworkController::_pushMemberUpdate(uint64_t now,uint64_t nwid,con
 				online = ( (lrt != _lastRequestTime.end()) && ((now - lrt->second) < ZT_NETWORK_AUTOCONF_DELAY) );
 			}
 			if (online) {
-				Dictionary<ZT_NETWORKCONFIG_METADATA_DICT_CAPACITY> *metaData = new Dictionary<ZT_NETWORKCONFIG_METADATA_DICT_CAPACITY>(mdstr.c_str());
+				Dictionary<ZT_NETWORKCONFIG_METADATA_DICT_CAPACITY> metaData(mdstr.c_str());
 				try {
-					this->request(nwid,InetAddress(),0,id,*metaData);
+					this->request(nwid,InetAddress(),0,id,metaData);
 				} catch ( ... ) {}
-				delete metaData;
 			}
 		}
 	} catch ( ... ) {}
diff --git a/controller/EmbeddedNetworkController.hpp b/controller/EmbeddedNetworkController.hpp
index 4dada88e..8a220139 100644
--- a/controller/EmbeddedNetworkController.hpp
+++ b/controller/EmbeddedNetworkController.hpp
@@ -34,6 +34,7 @@
 #include "../node/Utils.hpp"
 #include "../node/Address.hpp"
 #include "../node/InetAddress.hpp"
+#include "../node/NonCopyable.hpp"
 
 #include "../osdep/OSUtils.hpp"
 #include "../osdep/Thread.hpp"
@@ -50,7 +51,7 @@ namespace ZeroTier {
 
 class Node;
 
-class EmbeddedNetworkController : public NetworkController
+class EmbeddedNetworkController : public NetworkController,NonCopyable
 {
 public:
 	/**
diff --git a/controller/JSONDB.cpp b/controller/JSONDB.cpp
index a2fe7f2a..01eb50cd 100644
--- a/controller/JSONDB.cpp
+++ b/controller/JSONDB.cpp
@@ -107,9 +107,64 @@ bool JSONDB::writeRaw(const std::string &n,const std::string &obj)
 	}
 }
 
+bool JSONDB::hasNetwork(const uint64_t networkId) const
+{
+	Mutex::Lock _l(_networks_m);
+	std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
+	return (i != _networks.end());
+}
+
+bool JSONDB::getNetwork(const uint64_t networkId,nlohmann::json &config) const
+{
+	Mutex::Lock _l(_networks_m);
+	std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
+	if (i == _networks.end())
+		return false;
+	config = i->second.config;
+	return true;
+}
+
+bool JSONDB::getNetworkSummaryInfo(const uint64_t networkId,NetworkSummaryInfo &ns) const
+{
+	Mutex::Lock _l(_networks_m);
+	std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
+	if (i == _networks.end())
+		return false;
+	ns = i->second.summaryInfo;
+	return true;
+}
+
+int JSONDB::getNetworkAndMember(const uint64_t networkId,const uint64_t nodeId,nlohmann::json &networkConfig,nlohmann::json &memberConfig,NetworkSummaryInfo &ns) const
+{
+	Mutex::Lock _l(_networks_m);
+	std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
+	if (i == _networks.end())
+		return 0;
+	std::unordered_map<uint64_t,nlohmann::json>::const_iterator j(i->second.members.find(nodeId));
+	if (j == i->second.members.end())
+		return 1;
+	networkConfig = i->second.config;
+	memberConfig = j->second;
+	ns = i->second.summaryInfo;
+	return 3;
+}
+
+bool JSONDB::getNetworkMember(const uint64_t networkId,const uint64_t nodeId,nlohmann::json &memberConfig) const
+{
+	Mutex::Lock _l(_networks_m);
+	std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
+	if (i == _networks.end())
+		return false;
+	std::unordered_map<uint64_t,nlohmann::json>::const_iterator j(i->second.members.find(nodeId));
+	if (j == i->second.members.end())
+		return false;
+	memberConfig = j->second;
+	return true;
+}
+
 void JSONDB::saveNetwork(const uint64_t networkId,const nlohmann::json &networkConfig)
 {
-	char n[256];
+	char n[64];
 	Utils::snprintf(n,sizeof(n),"network/%.16llx",(unsigned long long)networkId);
 	writeRaw(n,OSUtils::jsonDump(networkConfig));
 	{
diff --git a/controller/JSONDB.hpp b/controller/JSONDB.hpp
index f89ff6c9..8db5cc48 100644
--- a/controller/JSONDB.hpp
+++ b/controller/JSONDB.hpp
@@ -63,63 +63,18 @@ public:
 
 	bool writeRaw(const std::string &n,const std::string &obj);
 
-	inline bool hasNetwork(const uint64_t networkId) const
-	{
-		Mutex::Lock _l(_networks_m);
-		std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
-		return (i != _networks.end());
-	}
+	bool hasNetwork(const uint64_t networkId) const;
 
-	inline bool getNetwork(const uint64_t networkId,nlohmann::json &config) const
-	{
-		Mutex::Lock _l(_networks_m);
-		std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
-		if (i == _networks.end())
-			return false;
-		config = i->second.config;
-		return true;
-	}
+	bool getNetwork(const uint64_t networkId,nlohmann::json &config) const;
 
-	inline bool getNetworkSummaryInfo(const uint64_t networkId,NetworkSummaryInfo &ns) const
-	{
-		Mutex::Lock _l(_networks_m);
-		std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
-		if (i == _networks.end())
-			return false;
-		ns = i->second.summaryInfo;
-		return true;
-	}
+	bool getNetworkSummaryInfo(const uint64_t networkId,NetworkSummaryInfo &ns) const;
 
 	/**
 	 * @return Bit mask: 0 == none, 1 == network only, 3 == network and member
 	 */
-	inline int getNetworkAndMember(const uint64_t networkId,const uint64_t nodeId,nlohmann::json &networkConfig,nlohmann::json &memberConfig,NetworkSummaryInfo &ns) const
-	{
-		Mutex::Lock _l(_networks_m);
-		std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
-		if (i == _networks.end())
-			return 0;
-		networkConfig = i->second.config;
-		ns = i->second.summaryInfo;
-		std::unordered_map<uint64_t,nlohmann::json>::const_iterator j(i->second.members.find(nodeId));
-		if (j == i->second.members.end())
-			return 1;
-		memberConfig = j->second;
-		return 3;
-	}
+	int getNetworkAndMember(const uint64_t networkId,const uint64_t nodeId,nlohmann::json &networkConfig,nlohmann::json &memberConfig,NetworkSummaryInfo &ns) const;
 
-	inline bool getNetworkMember(const uint64_t networkId,const uint64_t nodeId,nlohmann::json &memberConfig) const
-	{
-		Mutex::Lock _l(_networks_m);
-		std::unordered_map<uint64_t,_NW>::const_iterator i(_networks.find(networkId));
-		if (i == _networks.end())
-			return false;
-		std::unordered_map<uint64_t,nlohmann::json>::const_iterator j(i->second.members.find(nodeId));
-		if (j == i->second.members.end())
-			return false;
-		memberConfig = j->second;
-		return true;
-	}
+	bool getNetworkMember(const uint64_t networkId,const uint64_t nodeId,nlohmann::json &memberConfig) const;
 
 	void saveNetwork(const uint64_t networkId,const nlohmann::json &networkConfig);
 
diff --git a/ext/json/LICENSE.MIT b/ext/json/LICENSE.MIT
index e2ac4891..00599afe 100644
--- a/ext/json/LICENSE.MIT
+++ b/ext/json/LICENSE.MIT
@@ -1,14 +1,13 @@
-The library is licensed under the MIT License 
-<http://opensource.org/licenses/MIT>:
+MIT License 
 
-Copyright (c) 2013-2016 Niels Lohmann
+Copyright (c) 2013-2017 Niels Lohmann
 
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
diff --git a/ext/json/README.md b/ext/json/README.md
index 4bcbe97f..fc6dde9b 100644
--- a/ext/json/README.md
+++ b/ext/json/README.md
@@ -3,13 +3,34 @@
 [![Build Status](https://travis-ci.org/nlohmann/json.svg?branch=master)](https://travis-ci.org/nlohmann/json)
 [![Build Status](https://ci.appveyor.com/api/projects/status/1acb366xfyg3qybk/branch/develop?svg=true)](https://ci.appveyor.com/project/nlohmann/json)
 [![Coverage Status](https://img.shields.io/coveralls/nlohmann/json.svg)](https://coveralls.io/r/nlohmann/json)
-[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/fsf5FqYe6GoX68W6)
+[![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
+[![Codacy Badge](https://api.codacy.com/project/badge/Grade/f3732b3327e34358a0e9d1fe9f661f08)](https://www.codacy.com/app/nlohmann/json?utm_source=github.com&amp;utm_medium=referral&amp;utm_content=nlohmann/json&amp;utm_campaign=Badge_Grade)
+[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/nv9fOg0XVVhWmFFy)
 [![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](http://nlohmann.github.io/json)
 [![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
 [![Github Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
 [![Github Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](http://github.com/nlohmann/json/issues)
 [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/289/badge)](https://bestpractices.coreinfrastructure.org/projects/289)
 
+- [Design goals](#design-goals)
+- [Integration](#integration)
+- [Examples](#examples)
+  - [JSON as first-class data type](#json-as-first-class-data-type)
+  - [Serialization / Deserialization](#serialization--deserialization)
+  - [STL-like access](#stl-like-access)
+  - [Conversion from STL containers](#conversion-from-stl-containers)
+  - [JSON Pointer and JSON Patch](#json-pointer-and-json-patch)
+  - [Implicit conversions](#implicit-conversions)
+  - [Conversions to/from arbitrary types](#arbitrary-types-conversions)
+  - [Binary formats (CBOR and MessagePack)](#binary-formats-cbor-and-messagepack)
+- [Supported compilers](#supported-compilers)
+- [License](#license)
+- [Thanks](#thanks)
+- [Used third-party tools](#used-third-party-tools)
+- [Projects using JSON for Modern C++](#projects-using-json-for-modern-c)
+- [Notes](#notes)
+- [Execute unit tests](#execute-unit-tests)
+
 ## Design goals
 
 There are myriads of [JSON](http://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
@@ -24,7 +45,7 @@ Other aspects were not so important to us:
 
 - **Memory efficiency**. Each JSON object has an overhead of one pointer (the maximal size of a union) and one enumeration element (1 byte). The default generalization uses the following C++ data types: `std::string` for strings, `int64_t`, `uint64_t` or `double` for numbers, `std::map` for objects, `std::vector` for arrays, and `bool` for Booleans. However, you can template the generalized class `basic_json` to your needs.
 
-- **Speed**. We currently implement the parser as naive [recursive descent parser](http://en.wikipedia.org/wiki/Recursive_descent_parser) with hand coded string handling. It is fast enough, but a [LALR-parser](http://en.wikipedia.org/wiki/LALR_parser) may be even faster (but would consist of more files which makes the integration harder).
+- **Speed**. There are certainly [faster JSON libraries](https://github.com/miloyip/nativejson-benchmark#parsing-time) out there. However, if your goal is to speed up your development by adding JSON support with a single header, then this library is the way to go. If you know how to use a `std::vector` or `std::map`, you are already set.
 
 See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.github/CONTRIBUTING.md#please-dont) for more information.
 
@@ -44,9 +65,15 @@ to the files you want to use JSON objects. That's it. Do not forget to set the n
 
 :beer: If you are using OS X and [Homebrew](http://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann_json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann_json --HEAD`.
 
+:warning: [Version 3.0.0](https://github.com/nlohmann/json/wiki/Road-toward-3.0.0) is currently under development. Branch `develop` is used for the ongoing work and is probably **unstable**. Please use the `master` branch for the last stable version 2.1.1.
+
 
 ## Examples
 
+Beside the examples below, you may want to check the [documentation](https://nlohmann.github.io/json/) where each function contains a separate code example (e.g., check out [`emplace()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a602f275f0359ab181221384989810604.html#a602f275f0359ab181221384989810604)). All [example files](https://github.com/nlohmann/json/tree/develop/doc/examples) can be compiled and executed on their own (e.g., file [emplace.cpp](https://github.com/nlohmann/json/blob/develop/doc/examples/emplace.cpp)).
+
+### JSON as first-class data type
+
 Here are some examples to give you an idea how to use the class.
 
 Assume you want to create the JSON object
@@ -129,6 +156,8 @@ json array_not_object = { json::array({"currency", "USD"}), json::array({"value"
 
 ### Serialization / Deserialization
 
+#### To/from strings
+
 You can create an object (deserialization) by appending `_json` to a string literal:
 
 ```cpp
@@ -142,8 +171,14 @@ auto j2 = R"(
     "pi": 3.141
   }
 )"_json;
+```
+
+Note that without appending the `_json` suffix, the passed string literal is not parsed, but just used as JSON string value. That is, `json j = "{ \"happy\": true, \"pi\": 3.141 }"` would just store the string `"{ "happy": true, "pi": 3.141 }"` rather than parsing the actual object.
 
-// or explicitly
+The above example can also be expressed explicitly using `json::parse()`:
+
+```cpp
+// parse explicitly
 auto j3 = json::parse("{ \"happy\": true, \"pi\": 3.141 }");
 ```
 
@@ -162,6 +197,8 @@ std::cout << j.dump(4) << std::endl;
 // }
 ```
 
+#### To/from streams (e.g. files, string streams)
+
 You can also use streams to serialize and deserialize:
 
 ```cpp
@@ -176,10 +213,37 @@ std::cout << j;
 std::cout << std::setw(4) << j << std::endl;
 ```
 
-These operators work for any subclasses of `std::istream` or `std::ostream`.
+These operators work for any subclasses of `std::istream` or `std::ostream`. Here is the same example with files:
+
+```cpp
+// read a JSON file
+std::ifstream i("file.json");
+json j;
+i >> j;
+
+// write prettified JSON to another file
+std::ofstream o("pretty.json");
+o << std::setw(4) << j << std::endl;
+```
 
 Please note that setting the exception bit for `failbit` is inappropriate for this use case. It will result in program termination due to the `noexcept` specifier in use.
 
+#### Read from iterator range
+
+You can also read JSON from an iterator range; that is, from any container accessible by iterators whose content is stored as contiguous byte sequence, for instance a `std::vector<std::uint8_t>`:
+
+```cpp
+std::vector<std::uint8_t> v = {'t', 'r', 'u', 'e'};
+json j = json::parse(v.begin(), v.end());
+```
+
+You may leave the iterators for the range [begin, end):
+
+```cpp
+std::vector<std::uint8_t> v = {'t', 'r', 'u', 'e'};
+json j = json::parse(v);
+```
+
 
 ### STL-like access
 
@@ -192,6 +256,9 @@ j.push_back("foo");
 j.push_back(1);
 j.push_back(true);
 
+// also use emplace_back
+j.emplace_back(1.78);
+
 // iterate the array
 for (json::iterator it = j.begin(); it != j.end(); ++it) {
   std::cout << *it << '\n';
@@ -207,6 +274,9 @@ const std::string tmp = j[0];
 j[1] = 42;
 bool foo = j.at(2);
 
+// comparison
+j == "[\"foo\", 1, true]"_json;  // true
+
 // other stuff
 j.size();     // 3 entries
 j.empty();    // false
@@ -221,15 +291,15 @@ j.is_object();
 j.is_array();
 j.is_string();
 
-// comparison
-j == "[\"foo\", 1, true]"_json;  // true
-
 // create an object
 json o;
 o["foo"] = 23;
 o["bar"] = false;
 o["baz"] = 3.141;
 
+// also use emplace
+o.emplace("weather", "sunny");
+
 // special iterator member functions for objects
 for (json::iterator it = o.begin(); it != o.end(); ++it) {
   std::cout << it.key() << " : " << it.value() << "\n";
@@ -383,6 +453,252 @@ int vi = jn.get<int>();
 // etc.
 ```
 
+### Arbitrary types conversions
+
+Every type can be serialized in JSON, not just STL-containers and scalar types. Usually, you would do something along those lines:
+
+```cpp
+namespace ns {
+    // a simple struct to model a person
+    struct person {
+        std::string name;
+        std::string address;
+        int age;
+    };
+}
+
+ns::person p = {"Ned Flanders", "744 Evergreen Terrace", 60};
+
+// convert to JSON: copy each value into the JSON object
+json j;
+j["name"] = p.name;
+j["address"] = p.address;
+j["age"] = p.age;
+
+// ...
+
+// convert from JSON: copy each value from the JSON object
+ns::person p {
+    j["name"].get<std::string>(),
+    j["address"].get<std::string>(),
+    j["age"].get<int>()
+};
+```
+
+It works, but that's quite a lot of boilerplate... Fortunately, there's a better way:
+
+```cpp
+// create a person
+ns::person p {"Ned Flanders", "744 Evergreen Terrace", 60};
+
+// conversion: person -> json
+json j = p;
+
+std::cout << j << std::endl;
+// {"address":"744 Evergreen Terrace","age":60,"name":"Ned Flanders"}
+
+// conversion: json -> person
+ns::person p2 = j;
+
+// that's it
+assert(p == p2);
+```
+
+#### Basic usage
+
+To make this work with one of your types, you only need to provide two functions:
+
+```cpp
+using nlohmann::json;
+
+namespace ns {
+    void to_json(json& j, const person& p) {
+        j = json{{"name", p.name}, {"address", p.address}, {"age", p.age}};
+    }
+
+    void from_json(const json& j, person& p) {
+        p.name = j.at("name").get<std::string>();
+        p.address = j.at("address").get<std::string>();
+        p.age = j.at("age").get<int>();
+    }
+} // namespace ns
+```
+
+That's all! When calling the `json` constructor with your type, your custom `to_json` method will be automatically called.
+Likewise, when calling `get<your_type>()`, the `from_json` method will be called.
+
+Some important things:
+
+* Those methods **MUST** be in your type's namespace (which can be the global namespace), or the library will not be able to locate them (in this example, they are in namespace `ns`, where `person` is defined).
+* When using `get<your_type>()`, `your_type` **MUST** be [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible). (There is a way to bypass this requirement described later.)
+* In function `from_json`, use function [`at()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a93403e803947b86f4da2d1fb3345cf2c.html#a93403e803947b86f4da2d1fb3345cf2c) to access the object values rather than `operator[]`. In case a key does not exists, `at` throws an exception that you can handle, whereas `operator[]` exhibits undefined behavior.
+
+#### How do I convert third-party types?
+
+This requires a bit more advanced technique. But first, let's see how this conversion mechanism works:
+
+The library uses **JSON Serializers** to convert types to json.
+The default serializer for `nlohmann::json` is `nlohmann::adl_serializer` (ADL means [Argument-Dependent Lookup](http://en.cppreference.com/w/cpp/language/adl)).
+
+It is implemented like this (simplified):
+
+```cpp
+template <typename T>
+struct adl_serializer {
+    static void to_json(json& j, const T& value) {
+        // calls the "to_json" method in T's namespace
+    }
+
+    static void from_json(const json& j, T& value) {
+        // same thing, but with the "from_json" method
+    }
+};
+```
+
+This serializer works fine when you have control over the type's namespace. However, what about `boost::optional`, or `std::filesystem::path` (C++17)? Hijacking the `boost` namespace is pretty bad, and it's illegal to add something other than template specializations to `std`...
+
+To solve this, you need to add a specialization of `adl_serializer` to the `nlohmann` namespace, here's an example:
+
+```cpp
+// partial specialization (full specialization works too)
+namespace nlohmann {
+    template <typename T>
+    struct adl_serializer<boost::optional<T>> {
+        static void to_json(json& j, const boost::optional<T>& opt) {
+            if (opt == boost::none) {
+                j = nullptr;
+            } else {
+              j = *opt; // this will call adl_serializer<T>::to_json which will
+                        // find the free function to_json in T's namespace!
+            }
+        }
+
+        static void from_json(const json& j, boost::optional<T>& opt) {
+            if (j.is_null()) {
+                opt = boost::none;
+            } else {
+                opt = j.get<T>(); // same as above, but with 
+                                  // adl_serializer<T>::from_json
+            }
+        }
+    };
+}
+```
+
+#### How can I use `get()` for non-default constructible/non-copyable types?
+
+There is a way, if your type is [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible). You will need to specialize the `adl_serializer` as well, but with a special `from_json` overload:
+
+```cpp
+struct move_only_type {
+    move_only_type() = delete;
+    move_only_type(int ii): i(ii) {}
+    move_only_type(const move_only_type&) = delete;
+    move_only_type(move_only_type&&) = default;
+    
+    int i;
+};
+
+namespace nlohmann {
+    template <>
+    struct adl_serializer<move_only_type> {
+        // note: the return type is no longer 'void', and the method only takes
+        // one argument
+        static move_only_type from_json(const json& j) {
+            return {j.get<int>()};
+        }
+        
+        // Here's the catch! You must provide a to_json method! Otherwise you
+        // will not be able to convert move_only_type to json, since you fully
+        // specialized adl_serializer on that type
+        static void to_json(json& j, move_only_type t) {
+            j = t.i;
+        }
+    };
+}
+```
+
+#### Can I write my own serializer? (Advanced use)
+
+Yes. You might want to take a look at [`unit-udt.cpp`](https://github.com/nlohmann/json/blob/develop/test/src/unit-udt.cpp) in the test suite, to see a few examples.
+
+If you write your own serializer, you'll need to do a few things:
+
+* use a different `basic_json` alias than `nlohmann::json` (the last template parameter of `basic_json` is the `JSONSerializer`)
+* use your `basic_json` alias (or a template parameter) in all your `to_json`/`from_json` methods
+* use `nlohmann::to_json` and `nlohmann::from_json` when you need ADL
+
+Here is an example, without simplifications, that only accepts types with a size <= 32, and uses ADL.
+
+```cpp
+// You should use void as a second template argument
+// if you don't need compile-time checks on T
+template<typename T, typename SFINAE = typename std::enable_if<sizeof(T) <= 32>::type>
+struct less_than_32_serializer {
+    template <typename BasicJsonType>
+    static void to_json(BasicJsonType& j, T value) {
+        // we want to use ADL, and call the correct to_json overload
+        using nlohmann::to_json; // this method is called by adl_serializer,
+                                 // this is where the magic happens
+        to_json(j, value);
+    }
+    
+    template <typename BasicJsonType>
+    static void from_json(const BasicJsonType& j, T& value) {
+        // same thing here
+        using nlohmann::from_json;
+        from_json(j, value);
+    }
+};
+```
+
+Be **very** careful when reimplementing your serializer, you can stack overflow if you don't pay attention:
+
+```cpp
+template <typename T, void>
+struct bad_serializer
+{
+    template <typename BasicJsonType>
+    static void to_json(BasicJsonType& j, const T& value) {
+      // this calls BasicJsonType::json_serializer<T>::to_json(j, value);
+      // if BasicJsonType::json_serializer == bad_serializer ... oops!
+      j = value;
+    }
+    
+    template <typename BasicJsonType>
+    static void to_json(const BasicJsonType& j, T& value) {
+      // this calls BasicJsonType::json_serializer<T>::from_json(j, value);
+      // if BasicJsonType::json_serializer == bad_serializer ... oops!
+      value = j.template get<T>(); // oops!
+    }
+};
+```
+
+### Binary formats (CBOR and MessagePack)
+
+Though JSON is a ubiquitous data format, it is not a very compact format suitable for data exchange, for instance over a network. Hence, the library supports [CBOR](http://cbor.io) (Concise Binary Object Representation) and [MessagePack](http://msgpack.org) to efficiently encode JSON values to byte vectors and to decode such vectors.
+
+```cpp
+// create a JSON value
+json j = R"({"compact": true, "schema": 0})"_json;
+
+// serialize to CBOR
+std::vector<std::uint8_t> v_cbor = json::to_cbor(j);
+
+// 0xa2, 0x67, 0x63, 0x6f, 0x6d, 0x70, 0x61, 0x63, 0x74, 0xf5, 0x66, 0x73, 0x63, 0x68, 0x65, 0x6d, 0x61, 0x00
+
+// roundtrip
+json j_from_cbor = json::from_cbor(v_cbor);
+
+// serialize to MessagePack
+std::vector<std::uint8_t> v_msgpack = json::to_msgpack(j);
+
+// 0x82, 0xa7, 0x63, 0x6f, 0x6d, 0x70, 0x61, 0x63, 0x74, 0xc3, 0xa6, 0x73, 0x63, 0x68, 0x65, 0x6d, 0x61, 0x00
+
+// roundtrip
+json j_from_msgpack = json::from_msgpack(v_msgpack);
+```
+
 
 ## Supported compilers
 
@@ -391,6 +707,7 @@ Though it's 2016 already, the support for C++11 is still a bit sparse. Currently
 - GCC 4.9 - 6.0 (and possibly later)
 - Clang 3.4 - 3.9 (and possibly later)
 - Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
+- Microsoft Visual C++ 2017 / Build Tools 15.1.548.43366 (and possibly later)
 
 I would be happy to learn about other compilers/versions.
 
@@ -423,16 +740,14 @@ The following compilers are currently used in continuous integration at [Travis]
 | Clang 3.7.1     | Ubuntu 14.04.4 LTS           | clang version 3.7.1 (tags/RELEASE_371/final) |
 | Clang 3.8.0     | Ubuntu 14.04.4 LTS           | clang version 3.8.0 (tags/RELEASE_380/final) |
 | Clang 3.8.1     | Ubuntu 14.04.4 LTS           | clang version 3.8.1 (tags/RELEASE_381/final) |
-| Clang Xcode 6.1 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) |
-| Clang Xcode 6.2 | Darwin Kernel Version 13.4.0 (OSX 10.9.5) | Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) |
-| Clang Xcode 6.3 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn) |
 | Clang Xcode 6.4 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn) |
-| Clang Xcode 7.1 | Darwin Kernel Version 14.5.0 (OSX 10.10.5) | Apple LLVM version 7.0.0 (clang-700.1.76) |
-| Clang Xcode 7.2 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.0.2 (clang-700.1.81) |
 | Clang Xcode 7.3 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.3.0 (clang-703.0.29) |
-| Clang Xcode 8.0 | Darwin Kernel Version 15.6.0 (OSX 10.11.6) | Apple LLVM version 8.0.0 (clang-800.0.38) |
+| Clang Xcode 8.0 | Darwin Kernel Version 15.6.0 | Apple LLVM version 8.0.0 (clang-800.0.38) |
+| Clang Xcode 8.1 | Darwin Kernel Version 16.1.0 (macOS 10.12.1) | Apple LLVM version 8.0.0 (clang-800.0.42.1) |
+| Clang Xcode 8.2 | Darwin Kernel Version 16.1.0 (macOS 10.12.1) | Apple LLVM version 8.0.0 (clang-800.0.42.1) |
+| Clang Xcode 8.3 | Darwin Kernel Version 16.5.0 (macOS 10.12.4) | Apple LLVM version 8.1.0 (clang-802.0.38) |
 | Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25123.0 | 
-
+| Visual Studio 2017 | Windows Server 2016 | Microsoft (R) Build Engine version 15.1.548.43366 |
 
 ## License
 
@@ -440,7 +755,7 @@ The following compilers are currently used in continuous integration at [Travis]
 
 The class is licensed under the [MIT License](http://opensource.org/licenses/MIT):
 
-Copyright &copy; 2013-2016 [Niels Lohmann](http://nlohmann.me)
+Copyright &copy; 2013-2017 [Niels Lohmann](http://nlohmann.me)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
@@ -465,7 +780,7 @@ I deeply appreciate the help of the following people.
 - [Eric Cornelius](https://github.com/EricMCornelius) pointed out a bug in the handling with NaN and infinity values. He also improved the performance of the string escaping.
 - [易思龙](https://github.com/likebeta) implemented a conversion from anonymous enums.
 - [kepkin](https://github.com/kepkin) patiently pushed forward the support for Microsoft Visual studio.
-- [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators and helped with numerous hints and improvements.
+- [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators and helped with numerous hints and improvements. In particular, he pushed forward the implementation of user-defined types.
 - [Caio Luppi](https://github.com/caiovlp) fixed a bug in the Unicode handling.
 - [dariomt](https://github.com/dariomt) fixed some typos in the examples.
 - [Daniel Frey](https://github.com/d-frey) cleaned up some pointers and implemented exception-safe memory allocation.
@@ -493,14 +808,70 @@ I deeply appreciate the help of the following people.
 - [duncanwerner](https://github.com/duncanwerner) found a really embarrassing performance regression in the 2.0.0 release.
 - [Damien](https://github.com/dtoma) fixed one of the last conversion warnings.
 - [Thomas Braun](https://github.com/t-b) fixed a warning in a test case.
-- [Théo DELRIEU](https://github.com/theodelrieu) patiently and constructively oversaw the long way toward [iterator-range parsing](https://github.com/nlohmann/json/issues/290).
+- [Théo DELRIEU](https://github.com/theodelrieu) patiently and constructively oversaw the long way toward [iterator-range parsing](https://github.com/nlohmann/json/issues/290). He also implemented the magic behind the serialization/deserialization of user-defined types.
 - [Stefan](https://github.com/5tefan) fixed a minor issue in the documentation.
 - [Vasil Dimov](https://github.com/vasild) fixed the documentation regarding conversions from `std::multiset`.
 - [ChristophJud](https://github.com/ChristophJud) overworked the CMake files to ease project inclusion.
-- [Vladimir Petrigo](https://github.com/vpetrigo) made a SFINAE hack more readable.
+- [Vladimir Petrigo](https://github.com/vpetrigo) made a SFINAE hack more readable and added Visual Studio 17 to the build matrix.
 - [Denis Andrejew](https://github.com/seeekr) fixed a grammar issue in the README file.
-
-Thanks a lot for helping out!
+- [Pierre-Antoine Lacaze](https://github.com/palacaze) found a subtle bug in the `dump()` function.
+- [TurpentineDistillery](https://github.com/TurpentineDistillery) pointed to [`std::locale::classic()`](http://en.cppreference.com/w/cpp/locale/locale/classic) to avoid too much locale joggling, found some nice performance improvements in the parser, improved the benchmarking code, and realized locale-independent number parsing and printing.
+- [cgzones](https://github.com/cgzones) had an idea how to fix the Coverity scan.
+- [Jared Grubb](https://github.com/jaredgrubb) silenced a nasty documentation warning.
+- [Yixin Zhang](https://github.com/qwename) fixed an integer overflow check.
+- [Bosswestfalen](https://github.com/Bosswestfalen) merged two iterator classes into a smaller one.
+- [Daniel599](https://github.com/Daniel599) helped to get Travis execute the tests with Clang's sanitizers.
+- [Jonathan Lee](https://github.com/vjon) fixed an example in the README file.
+- [gnzlbg](https://github.com/gnzlbg) supported the implementation of user-defined types.
+- [Alexej Harm](https://github.com/qis) helped to get the user-defined types working with Visual Studio.
+- [Jared Grubb](https://github.com/jaredgrubb) supported the implementation of user-defined types.
+- [EnricoBilla](https://github.com/EnricoBilla) noted a typo in an example.
+- [Martin Hořeňovský](https://github.com/horenmar) found a way for a 2x speedup for the compilation time of the test suite.
+- [ukhegg](https://github.com/ukhegg) found proposed an improvement for the examples section.
+- [rswanson-ihi](https://github.com/rswanson-ihi) noted a typo in the README.
+- [Mihai Stan](https://github.com/stanmihai4) fixed a bug in the comparison with `nullptr`s.
+- [Tushar Maheshwari](https://github.com/tusharpm) added [cotire](https://github.com/sakra/cotire) support to speed up the compilation.
+- [TedLyngmo](https://github.com/TedLyngmo) noted a typo in the README, removed unnecessary bit arithmetic, and fixed some `-Weffc++` warnings.
+- [Krzysztof Woś](https://github.com/krzysztofwos) made exceptions more visible.
+- [ftillier](https://github.com/ftillier) fixed a compiler warning.
+- [tinloaf](https://github.com/tinloaf) made sure all pushed warnings are properly popped.
+- [Fytch](https://github.com/Fytch) found a bug in the documentation.
+
+Thanks a lot for helping out! Please [let me know](mailto:mail@nlohmann.me) if I forgot someone.
+
+
+## Used third-party tools
+
+The library itself contains of a single header file licensed under the MIT license. However, it is built, tested, documented, and whatnot using a lot of third-party tools and services. Thanks a lot!
+
+- [**American fuzzy lop**](http://lcamtuf.coredump.cx/afl/) for fuzz testing
+- [**AppVeyor**](https://www.appveyor.com) for [continuous integration](https://ci.appveyor.com/project/nlohmann/json) on Windows
+- [**Artistic Style**](http://astyle.sourceforge.net) for automatic source code identation
+- [**benchpress**](https://github.com/sbs-ableton/benchpress) to benchmark the code
+- [**Catch**](https://github.com/philsquared/Catch) for the unit tests
+- [**Clang**](http://clang.llvm.org) for compilation with code sanitizers
+- [**Cmake**](https://cmake.org) for build automation
+- [**Codacity**](https://www.codacy.com) for further [code analysis](https://www.codacy.com/app/nlohmann/json)
+- [**cotire**](https://github.com/sakra/cotire) to speed of compilation
+- [**Coveralls**](https://coveralls.io) to measure [code coverage](https://coveralls.io/github/nlohmann/json)
+- [**Coverity Scan**](https://scan.coverity.com) for [static analysis](https://scan.coverity.com/projects/nlohmann-json)
+- [**cppcheck**](http://cppcheck.sourceforge.net) for static analysis
+- [**cxxopts**](https://github.com/jarro2783/cxxopts) to let benchpress parse command-line parameters
+- [**Doxygen**](http://www.stack.nl/~dimitri/doxygen/) to generate [documentation](https://nlohmann.github.io/json/)
+- [**git-update-ghpages**](https://github.com/rstacruz/git-update-ghpages) to upload the documentation to gh-pages
+- [**Github Changelog Generator**](https://github.com/skywinder/github-changelog-generator) to generate the [ChangeLog](https://github.com/nlohmann/json/blob/develop/ChangeLog.md)
+- [**libFuzzer**](http://llvm.org/docs/LibFuzzer.html) to implement fuzz testing for OSS-Fuzz
+- [**OSS-Fuzz**](https://github.com/google/oss-fuzz) for continuous fuzz testing of the library
+- [**re2c**](http://re2c.org) to generate an automaton for the lexical analysis
+- [**send_to_wandbox**](https://github.com/nlohmann/json/blob/develop/doc/scripts/send_to_wandbox.py) to send code examples to [Wandbox](http://melpon.org/wandbox)
+- [**Travis**](https://travis-ci.org) for [continuous integration](https://travis-ci.org/nlohmann/json) on Linux and macOS
+- [**Valgrind**](http://valgrind.org) to check for correct memory management
+- [**Wandbox**](http://melpon.org/wandbox) for [online examples](http://melpon.org/wandbox/permlink/4NEU6ZZMoM9lpIex)
+
+
+## Projects using JSON for Modern C++
+
+The library is currently used in Apple macOS Sierra and iOS 10. I am not sure what they are using the library for, but I am happy that it runs on so many devices.
 
 
 ## Notes
@@ -512,6 +883,10 @@ Thanks a lot for helping out!
   - Other encodings such as Latin-1, UTF-16, or UTF-32 are not supported and will yield parse errors.
   - [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1) will not be replaced by the library.
   - Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
+  - The strings stored in the library are UTF-8 encoded. When using the default string type (`std::string`), note that its length/size functions return the number of stored bytes rather than the number of characters or glyphs.
+- The code can be compiled without C++ **runtime type identification** features; that is, you can use the `-fno-rtti` compiler flag.
+- **Exceptions** are used widely within the library. They can, however, be switched off with either using the compiler flag `-fno-exceptions` or by defining the symbol `JSON_NOEXCEPTION`. In this case, exceptions are replaced by an `abort()` call.
+- By default, the library does not preserve the **insertion order of object elements**. This is standards-compliant, as the [JSON standard](https://tools.ietf.org/html/rfc7159.html) defines objects as "an unordered collection of zero or more name/value pairs". If you do want to preserve the insertion order, you can specialize the object type with containers like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map).
 
 
 ## Execute unit tests
@@ -519,10 +894,11 @@ Thanks a lot for helping out!
 To compile and run the tests, you need to execute
 
 ```sh
-$ make check
+$ make json_unit -Ctest
+$ ./test/json_unit "*"
 
 ===============================================================================
-All tests passed (8905491 assertions in 36 test cases)
+All tests passed (11203022 assertions in 48 test cases)
 ```
 
 Alternatively, you can use [CMake](https://cmake.org) and run
diff --git a/ext/json/json.hpp b/ext/json/json.hpp
index 9d48e7a6..8a8b876a 100644
--- a/ext/json/json.hpp
+++ b/ext/json/json.hpp
@@ -1,7 +1,7 @@
 /*
     __ _____ _____ _____
  __|  |   __|     |   | |  JSON for Modern C++
-|  |  |__   |  |  | | | |  version 2.0.10
+|  |  |__   |  |  | | | |  version 2.1.1
 |_____|_____|_____|_|___|  https://github.com/nlohmann/json
 
 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
@@ -29,42 +29,39 @@ SOFTWARE.
 #ifndef NLOHMANN_JSON_HPP
 #define NLOHMANN_JSON_HPP
 
-#include <algorithm> // all_of, for_each, transform
+#include <algorithm> // all_of, copy, fill, find, for_each, none_of, remove, reverse, transform
 #include <array> // array
 #include <cassert> // assert
-#include <cctype> // isdigit
 #include <ciso646> // and, not, or
-#include <cmath> // isfinite, ldexp, signbit
+#include <clocale> // lconv, localeconv
+#include <cmath> // isfinite, labs, ldexp, signbit
 #include <cstddef> // nullptr_t, ptrdiff_t, size_t
 #include <cstdint> // int64_t, uint64_t
-#include <cstdlib> // strtod, strtof, strtold, strtoul
+#include <cstdlib> // abort, strtod, strtof, strtold, strtoul, strtoll, strtoull
 #include <cstring> // strlen
+#include <forward_list> // forward_list
 #include <functional> // function, hash, less
 #include <initializer_list> // initializer_list
-#include <iomanip> // setw
 #include <iostream> // istream, ostream
-#include <iterator> // advance, begin, bidirectional_iterator_tag, distance, end, inserter, iterator, iterator_traits, next, random_access_iterator_tag, reverse_iterator
+#include <iterator> // advance, begin, back_inserter, bidirectional_iterator_tag, distance, end, inserter, iterator, iterator_traits, next, random_access_iterator_tag, reverse_iterator
 #include <limits> // numeric_limits
 #include <locale> // locale
 #include <map> // map
 #include <memory> // addressof, allocator, allocator_traits, unique_ptr
 #include <numeric> // accumulate
 #include <sstream> // stringstream
-#include <stdexcept> // domain_error, invalid_argument, out_of_range
 #include <string> // getline, stoi, string, to_string
-#include <type_traits> // add_pointer, enable_if, is_arithmetic, is_base_of, is_const, is_constructible, is_convertible, is_floating_point, is_integral, is_nothrow_move_assignable, std::is_nothrow_move_constructible, std::is_pointer, std::is_reference, std::is_same, remove_const, remove_pointer, remove_reference
+#include <type_traits> // add_pointer, conditional, decay, enable_if, false_type, integral_constant, is_arithmetic, is_base_of, is_const, is_constructible, is_convertible, is_default_constructible, is_enum, is_floating_point, is_integral, is_nothrow_move_assignable, is_nothrow_move_constructible, is_pointer, is_reference, is_same, is_scalar, is_signed, remove_const, remove_cv, remove_pointer, remove_reference, true_type, underlying_type
 #include <utility> // declval, forward, make_pair, move, pair, swap
 #include <vector> // vector
 
 // exclude unsupported compilers
 #if defined(__clang__)
-    #define CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
-    #if CLANG_VERSION < 30400
+    #if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
         #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
     #endif
 #elif defined(__GNUC__)
-    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
-    #if GCC_VERSION < 40900
+    #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40900
         #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
     #endif
 #endif
@@ -90,6 +87,17 @@ SOFTWARE.
     #define JSON_DEPRECATED
 #endif
 
+// allow to disable exceptions
+#if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND)) && not defined(JSON_NOEXCEPTION)
+    #define JSON_THROW(exception) throw exception
+    #define JSON_TRY try
+    #define JSON_CATCH(exception) catch(exception)
+#else
+    #define JSON_THROW(exception) std::abort()
+    #define JSON_TRY if(true)
+    #define JSON_CATCH(exception) if(false)
+#endif
+
 /*!
 @brief namespace for Niels Lohmann
 @see https://github.com/nlohmann
@@ -98,1466 +106,2175 @@ SOFTWARE.
 namespace nlohmann
 {
 
-
 /*!
 @brief unnamed namespace with internal helper functions
-@since version 1.0.0
+
+This namespace collects some functions that could not be defined inside the
+@ref basic_json class.
+
+@since version 2.1.0
 */
-namespace
+namespace detail
 {
+////////////////
+// exceptions //
+////////////////
+
 /*!
-@brief Helper to determine whether there's a key_type for T.
+@brief general exception of the @ref basic_json class
 
-Thus helper is used to tell associative containers apart from other containers
-such as sequence containers. For instance, `std::map` passes the test as it
-contains a `mapped_type`, whereas `std::vector` fails the test.
+Extension of std::exception objects with a member @a id for exception ids.
 
-@sa http://stackoverflow.com/a/7728728/266378
-@since version 1.0.0, overworked in version 2.0.6
+@note To have nothrow-copy-constructible exceptions, we internally use
+      std::runtime_error which can cope with arbitrary-length error messages.
+      Intermediate strings are built with static functions and then passed to
+      the actual constructor.
+
+@since version 3.0.0
 */
-template<typename T>
-struct has_mapped_type
+class exception : public std::exception
 {
+  public:
+    /// returns the explanatory string
+    virtual const char* what() const noexcept override
+    {
+        return m.what();
+    }
+
+    /// the id of the exception
+    const int id;
+
+  protected:
+    exception(int id_, const char* what_arg)
+        : id(id_), m(what_arg)
+    {}
+
+    static std::string name(const std::string& ename, int id)
+    {
+        return "[json.exception." + ename + "." + std::to_string(id) + "] ";
+    }
+
   private:
-    template <typename U, typename = typename U::mapped_type>
-    static int detect(U&&);
+    /// an exception object as storage for error messages
+    std::runtime_error m;
+};
 
-    static void detect(...);
+/*!
+@brief exception indicating a parse error
+
+This excpetion is thrown by the library when a parse error occurs. Parse
+errors can occur during the deserialization of JSON text as well as when
+using JSON Patch.
+
+Member @a byte holds the byte index of the last read character in the input
+file.
+
+@note For an input with n bytes, 1 is the index of the first character
+      and n+1 is the index of the terminating null byte or the end of
+      file. This also holds true when reading a byte vector (CBOR or
+      MessagePack).
+
+Exceptions have ids 1xx.
+
+name / id                      | example massage | description
+------------------------------ | --------------- | -------------------------
+json.exception.parse_error.101 | parse error at 2: unexpected end of input; expected string literal | This error indicates a syntax error while deserializing a JSON text. The error message describes that an unexpected token (character) was encountered, and the member @a byte indicates the error position.
+json.exception.parse_error.102 | parse error at 14: missing or wrong low surrogate | JSON uses the `\uxxxx` format to describe Unicode characters. Code points above above 0xFFFF are split into two `\uxxxx` entries ("surrogate pairs"). This error indicates that the surrogate pair is incomplete or contains an invalid code point.
+json.exception.parse_error.103 | parse error: code points above 0x10FFFF are invalid | Unicode supports code points up to 0x10FFFF. Code points above 0x10FFFF are invalid.
+json.exception.parse_error.104 | parse error: JSON patch must be an array of objects | [RFC 6902](https://tools.ietf.org/html/rfc6902) requires a JSON Patch document to be a JSON document that represents an array of objects.
+json.exception.parse_error.105 | parse error: operation must have string member 'op' | An operation of a JSON Patch document must contain exactly one "op" member, whose value indicates the operation to perform. Its value must be one of "add", "remove", "replace", "move", "copy", or "test"; other values are errors.
+json.exception.parse_error.106 | parse error: array index '01' must not begin with '0' | An array index in a JSON Pointer ([RFC 6901](https://tools.ietf.org/html/rfc6901)) may be `0` or any number wihtout a leading `0`.
+json.exception.parse_error.107 | parse error: JSON pointer must be empty or begin with '/' - was: 'foo' | A JSON Pointer must be a Unicode string containing a sequence of zero or more reference tokens, each prefixed by a `/` character.
+json.exception.parse_error.108 | parse error: escape character '~' must be followed with '0' or '1' | In a JSON Pointer, only `~0` and `~1` are valid escape sequences.
+json.exception.parse_error.109 | parse error: array index 'one' is not a number | A JSON Pointer array index must be a number.
+json.exception.parse_error.110 | parse error at 1: cannot read 2 bytes from vector | When parsing CBOR or MessagePack, the byte vector ends before the complete value has been read.
+json.exception.parse_error.111 | parse error: bad input stream | Parsing CBOR or MessagePack from an input stream where the [`badbit` or `failbit`](http://en.cppreference.com/w/cpp/io/ios_base/iostate) is set.
+json.exception.parse_error.112 | parse error at 1: error reading CBOR; last byte: 0xf8 | Not all types of CBOR or MessagePack are supported. This exception occurs if an unsupported byte was read.
+json.exception.parse_error.113 | parse error at 2: expected a CBOR string; last byte: 0x98 | While parsing a map key, a value that is not a string has been read.
+
+@since version 3.0.0
+*/
+class parse_error : public exception
+{
   public:
-    static constexpr bool value =
-        std::is_integral<decltype(detect(std::declval<T>()))>::value;
-};
+    /*!
+    @brief create a parse error exception
+    @param[in] id         the id of the exception
+    @param[in] byte_      the byte index where the error occured (or 0 if
+                          the position cannot be determined)
+    @param[in] what_arg   the explanatory string
+    @return parse_error object
+    */
+    static parse_error create(int id, size_t byte_, const std::string& what_arg)
+    {
+        std::string w = exception::name("parse_error", id) + "parse error" +
+                        (byte_ != 0 ? (" at " + std::to_string(byte_)) : "") +
+                        ": " + what_arg;
+        return parse_error(id, byte_, w.c_str());
+    }
 
-}
+    /*!
+    @brief byte index of the parse error
+
+    The byte index of the last read character in the input file.
+
+    @note For an input with n bytes, 1 is the index of the first character
+          and n+1 is the index of the terminating null byte or the end of
+          file. This also holds true when reading a byte vector (CBOR or
+          MessagePack).
+    */
+    const size_t byte;
+
+  private:
+    parse_error(int id_, size_t byte_, const char* what_arg)
+        : exception(id_, what_arg), byte(byte_)
+    {}
+};
 
 /*!
-@brief a class to store JSON values
+@brief exception indicating errors with iterators
+
+Exceptions have ids 2xx.
+
+name / id                           | example massage | description
+----------------------------------- | --------------- | -------------------------
+json.exception.invalid_iterator.201 | iterators are not compatible | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
+json.exception.invalid_iterator.202 | iterator does not fit current value | In an erase or insert function, the passed iterator @a pos does not belong to the JSON value for which the function was called. It hence does not define a valid position for the deletion/insertion.
+json.exception.invalid_iterator.203 | iterators do not fit current value | Either iterator passed to function @ref erase(IteratorType first, IteratorType last) does not belong to the JSON value from which values shall be erased. It hence does not define a valid range to delete values from.
+json.exception.invalid_iterator.204 | iterators out of range | When an iterator range for a primitive type (number, boolean, or string) is passed to a constructor or an erase function, this range has to be exactly (@ref begin(), @ref end()), because this is the only way the single stored value is expressed. All other ranges are invalid.
+json.exception.invalid_iterator.205 | iterator out of range | When an iterator for a primitive type (number, boolean, or string) is passed to an erase function, the iterator has to be the @ref begin() iterator, because it is the only way to address the stored value. All other iterators are invalid.
+json.exception.invalid_iterator.206 | cannot construct with iterators from null | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) belong to a JSON null value and hence to not define a valid range.
+json.exception.invalid_iterator.207 | cannot use key() for non-object iterators | The key() member function can only be used on iterators belonging to a JSON object, because other types do not have a concept of a key.
+json.exception.invalid_iterator.208 | cannot use operator[] for object iterators | The operator[] to specify a concrete offset cannot be used on iterators belonging to a JSON object, because JSON objects are unordered.
+json.exception.invalid_iterator.209 | cannot use offsets with object iterators | The offset operators (+, -, +=, -=) cannot be used on iterators belonging to a JSON object, because JSON objects are unordered.
+json.exception.invalid_iterator.210 | iterators do not fit | The iterator range passed to the insert function are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
+json.exception.invalid_iterator.211 | passed iterators may not belong to container | The iterator range passed to the insert function must not be a subrange of the container to insert to.
+json.exception.invalid_iterator.212 | cannot compare iterators of different containers | When two iterators are compared, they must belong to the same container.
+json.exception.invalid_iterator.213 | cannot compare order of object iterators | The order of object iterators cannot be compated, because JSON objects are unordered.
+json.exception.invalid_iterator.214 | cannot get value | Cannot get value for iterator: Either the iterator belongs to a null value or it is an iterator to a primitive type (number, boolean, or string), but the iterator is different to @ref begin().
+
+@since version 3.0.0
+*/
+class invalid_iterator : public exception
+{
+  public:
+    static invalid_iterator create(int id, const std::string& what_arg)
+    {
+        std::string w = exception::name("invalid_iterator", id) + what_arg;
+        return invalid_iterator(id, w.c_str());
+    }
 
-@tparam ObjectType type for JSON objects (`std::map` by default; will be used
-in @ref object_t)
-@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
-in @ref array_t)
-@tparam StringType type for JSON strings and object keys (`std::string` by
-default; will be used in @ref string_t)
-@tparam BooleanType type for JSON booleans (`bool` by default; will be used
-in @ref boolean_t)
-@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
-default; will be used in @ref number_integer_t)
-@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
-`uint64_t` by default; will be used in @ref number_unsigned_t)
-@tparam NumberFloatType type for JSON floating-point numbers (`double` by
-default; will be used in @ref number_float_t)
-@tparam AllocatorType type of the allocator to use (`std::allocator` by
-default)
+  private:
+    invalid_iterator(int id_, const char* what_arg)
+        : exception(id_, what_arg)
+    {}
+};
 
-@requirement The class satisfies the following concept requirements:
-- Basic
- - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
-   JSON values can be default constructed. The result will be a JSON null value.
- - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
-   A JSON value can be constructed from an rvalue argument.
- - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
-   A JSON value can be copy-constructed from an lvalue expression.
- - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
-   A JSON value van be assigned from an rvalue argument.
- - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
-   A JSON value can be copy-assigned from an lvalue expression.
- - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
-   JSON values can be destructed.
-- Layout
- - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
-   JSON values have
-   [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
-   All non-static data members are private and standard layout types, the class
-   has no virtual functions or (virtual) base classes.
-- Library-wide
- - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
-   JSON values can be compared with `==`, see @ref
-   operator==(const_reference,const_reference).
- - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
-   JSON values can be compared with `<`, see @ref
-   operator<(const_reference,const_reference).
- - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
-   Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
-   other compatible types, using unqualified function call @ref swap().
- - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
-   JSON values can be compared against `std::nullptr_t` objects which are used
-   to model the `null` value.
-- Container
- - [Container](http://en.cppreference.com/w/cpp/concept/Container):
-   JSON values can be used like STL containers and provide iterator access.
- - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
-   JSON values can be used like STL containers and provide reverse iterator
-   access.
+/*!
+@brief exception indicating executing a member function with a wrong type
+
+Exceptions have ids 3xx.
+
+name / id                     | example massage | description
+----------------------------- | --------------- | -------------------------
+json.exception.type_error.301 | cannot create object from initializer list | To create an object from an initializer list, the initializer list must consist only of a list of pairs whose first element is a string. When this constraint is violated, an array is created instead.
+json.exception.type_error.302 | type must be object, but is array | During implicit or explicit value conversion, the JSON type must be compatible to the target type. For instance, a JSON string can only be converted into string types, but not into numbers or boolean types.
+json.exception.type_error.303 | incompatible ReferenceType for get_ref, actual type is object | To retrieve a reference to a value stored in a @ref basic_json object with @ref get_ref, the type of the reference must match the value type. For instance, for a JSON array, the @a ReferenceType must be @ref array_t&.
+json.exception.type_error.304 | cannot use at() with string | The @ref at() member functions can only be executed for certain JSON types.
+json.exception.type_error.305 | cannot use operator[] with string | The @ref operator[] member functions can only be executed for certain JSON types.
+json.exception.type_error.306 | cannot use value() with string | The @ref value() member functions can only be executed for certain JSON types.
+json.exception.type_error.307 | cannot use erase() with string | The @ref erase() member functions can only be executed for certain JSON types.
+json.exception.type_error.308 | cannot use push_back() with string | The @ref push_back() and @ref operator+= member functions can only be executed for certain JSON types.
+json.exception.type_error.309 | cannot use insert() with | The @ref insert() member functions can only be executed for certain JSON types.
+json.exception.type_error.310 | cannot use swap() with number | The @ref swap() member functions can only be executed for certain JSON types.
+json.exception.type_error.311 | cannot use emplace_back() with string | The @ref emplace_back() member function can only be executed for certain JSON types.
+json.exception.type_error.313 | invalid value to unflatten | The @ref unflatten function converts an object whose keys are JSON Pointers back into an arbitrary nested JSON value. The JSON Pointers must not overlap, because then the resulting value would not be well defined.
+json.exception.type_error.314 | only objects can be unflattened | The @ref unflatten function only works for an object whose keys are JSON Pointers.
+json.exception.type_error.315 | values in object must be primitive | The @ref unflatten function only works for an object whose keys are JSON Pointers and whose values are primitive.
+
+@since version 3.0.0
+*/
+class type_error : public exception
+{
+  public:
+    static type_error create(int id, const std::string& what_arg)
+    {
+        std::string w = exception::name("type_error", id) + what_arg;
+        return type_error(id, w.c_str());
+    }
 
-@invariant The member variables @a m_value and @a m_type have the following
-relationship:
-- If `m_type == value_t::object`, then `m_value.object != nullptr`.
-- If `m_type == value_t::array`, then `m_value.array != nullptr`.
-- If `m_type == value_t::string`, then `m_value.string != nullptr`.
-The invariants are checked by member function assert_invariant().
+  private:
+    type_error(int id_, const char* what_arg)
+        : exception(id_, what_arg)
+    {}
+};
 
-@internal
-@note ObjectType trick from http://stackoverflow.com/a/9860911
-@endinternal
+/*!
+@brief exception indicating access out of the defined range
 
-@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
-Format](http://rfc7159.net/rfc7159)
+Exceptions have ids 4xx.
 
-@since version 1.0.0
+name / id                       | example massage | description
+------------------------------- | --------------- | -------------------------
+json.exception.out_of_range.401 | array index 3 is out of range | The provided array index @a i is larger than @a size-1.
+json.exception.out_of_range.402 | array index '-' (3) is out of range | The special array index `-` in a JSON Pointer never describes a valid element of the array, but the index past the end. That is, it can only be used to add elements at this position, but not to read it.
+json.exception.out_of_range.403 | key 'foo' not found | The provided key was not found in the JSON object.
+json.exception.out_of_range.404 | unresolved reference token 'foo' | A reference token in a JSON Pointer could not be resolved.
+json.exception.out_of_range.405 | JSON pointer has no parent | The JSON Patch operations 'remove' and 'add' can not be applied to the root element of the JSON value.
+json.exception.out_of_range.406 | number overflow parsing '10E1000' | A parsed number could not be stored as without changing it to NaN or INF.
 
-@nosubgrouping
+@since version 3.0.0
 */
-template <
-    template<typename U, typename V, typename... Args> class ObjectType = std::map,
-    template<typename U, typename... Args> class ArrayType = std::vector,
-    class StringType = std::string,
-    class BooleanType = bool,
-    class NumberIntegerType = std::int64_t,
-    class NumberUnsignedType = std::uint64_t,
-    class NumberFloatType = double,
-    template<typename U> class AllocatorType = std::allocator
-    >
-class basic_json
+class out_of_range : public exception
 {
+  public:
+    static out_of_range create(int id, const std::string& what_arg)
+    {
+        std::string w = exception::name("out_of_range", id) + what_arg;
+        return out_of_range(id, w.c_str());
+    }
+
   private:
-    /// workaround type for MSVC
-    using basic_json_t = basic_json<ObjectType, ArrayType, StringType,
-          BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType,
-          AllocatorType>;
+    out_of_range(int id_, const char* what_arg)
+        : exception(id_, what_arg)
+    {}
+};
 
-  public:
-    // forward declarations
-    template<typename U> class iter_impl;
-    template<typename Base> class json_reverse_iterator;
-    class json_pointer;
+/*!
+@brief exception indicating other errors
 
-    /////////////////////
-    // container types //
-    /////////////////////
+Exceptions have ids 5xx.
 
-    /// @name container types
-    /// The canonic container types to use @ref basic_json like any other STL
-    /// container.
-    /// @{
+name / id                      | example massage | description
+------------------------------ | --------------- | -------------------------
+json.exception.other_error.501 | unsuccessful: {"op":"test","path":"/baz", "value":"bar"} | A JSON Patch operation 'test' failed. The unsuccessful operation is also printed.
 
-    /// the type of elements in a basic_json container
-    using value_type = basic_json;
+@since version 3.0.0
+*/
+class other_error : public exception
+{
+  public:
+    static other_error create(int id, const std::string& what_arg)
+    {
+        std::string w = exception::name("other_error", id) + what_arg;
+        return other_error(id, w.c_str());
+    }
 
-    /// the type of an element reference
-    using reference = value_type&;
-    /// the type of an element const reference
-    using const_reference = const value_type&;
+  private:
+    other_error(int id_, const char* what_arg)
+        : exception(id_, what_arg)
+    {}
+};
 
-    /// a type to represent differences between iterators
-    using difference_type = std::ptrdiff_t;
-    /// a type to represent container sizes
-    using size_type = std::size_t;
 
-    /// the allocator type
-    using allocator_type = AllocatorType<basic_json>;
 
-    /// the type of an element pointer
-    using pointer = typename std::allocator_traits<allocator_type>::pointer;
-    /// the type of an element const pointer
-    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
+///////////////////////////
+// JSON type enumeration //
+///////////////////////////
 
-    /// an iterator for a basic_json container
-    using iterator = iter_impl<basic_json>;
-    /// a const iterator for a basic_json container
-    using const_iterator = iter_impl<const basic_json>;
-    /// a reverse iterator for a basic_json container
-    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
-    /// a const reverse iterator for a basic_json container
-    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;
+/*!
+@brief the JSON type enumeration
+
+This enumeration collects the different JSON types. It is internally used to
+distinguish the stored values, and the functions @ref basic_json::is_null(),
+@ref basic_json::is_object(), @ref basic_json::is_array(),
+@ref basic_json::is_string(), @ref basic_json::is_boolean(),
+@ref basic_json::is_number() (with @ref basic_json::is_number_integer(),
+@ref basic_json::is_number_unsigned(), and @ref basic_json::is_number_float()),
+@ref basic_json::is_discarded(), @ref basic_json::is_primitive(), and
+@ref basic_json::is_structured() rely on it.
+
+@note There are three enumeration entries (number_integer, number_unsigned, and
+number_float), because the library distinguishes these three types for numbers:
+@ref basic_json::number_unsigned_t is used for unsigned integers,
+@ref basic_json::number_integer_t is used for signed integers, and
+@ref basic_json::number_float_t is used for floating-point numbers or to
+approximate integers which do not fit in the limits of their respective type.
+
+@sa @ref basic_json::basic_json(const value_t value_type) -- create a JSON
+value with the default value for a given type
 
-    /// @}
+@since version 1.0.0
+*/
+enum class value_t : uint8_t
+{
+    null,            ///< null value
+    object,          ///< object (unordered set of name/value pairs)
+    array,           ///< array (ordered collection of values)
+    string,          ///< string value
+    boolean,         ///< boolean value
+    number_integer,  ///< number value (signed integer)
+    number_unsigned, ///< number value (unsigned integer)
+    number_float,    ///< number value (floating-point)
+    discarded        ///< discarded by the the parser callback function
+};
 
+/*!
+@brief comparison operator for JSON types
 
-    /*!
-    @brief returns the allocator associated with the container
-    */
-    static allocator_type get_allocator()
+Returns an ordering that is similar to Python:
+- order: null < boolean < number < object < array < string
+- furthermore, each type is not smaller than itself
+
+@since version 1.0.0
+*/
+inline bool operator<(const value_t lhs, const value_t rhs) noexcept
+{
+    static constexpr std::array<uint8_t, 8> order = {{
+            0, // null
+            3, // object
+            4, // array
+            5, // string
+            1, // boolean
+            2, // integer
+            2, // unsigned
+            2, // float
+        }
+    };
+
+    // discarded values are not comparable
+    if (lhs == value_t::discarded or rhs == value_t::discarded)
     {
-        return allocator_type();
+        return false;
     }
 
+    return order[static_cast<std::size_t>(lhs)] <
+           order[static_cast<std::size_t>(rhs)];
+}
 
-    ///////////////////////////
-    // JSON value data types //
-    ///////////////////////////
 
-    /// @name JSON value data types
-    /// The data types to store a JSON value. These types are derived from
-    /// the template arguments passed to class @ref basic_json.
-    /// @{
+/////////////
+// helpers //
+/////////////
 
-    /*!
-    @brief a type for an object
+// alias templates to reduce boilerplate
+template<bool B, typename T = void>
+using enable_if_t = typename std::enable_if<B, T>::type;
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
-    > An object is an unordered collection of zero or more name/value pairs,
-    > where a name is a string and a value is a string, number, boolean, null,
-    > object, or array.
+template<typename T>
+using uncvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type;
 
-    To store objects in C++, a type is defined by the template parameters
-    described below.
+/*
+Implementation of two C++17 constructs: conjunction, negation. This is needed
+to avoid evaluating all the traits in a condition
 
-    @tparam ObjectType  the container to store objects (e.g., `std::map` or
-    `std::unordered_map`)
-    @tparam StringType the type of the keys or names (e.g., `std::string`).
-    The comparison function `std::less<StringType>` is used to order elements
-    inside the container.
-    @tparam AllocatorType the allocator to use for objects (e.g.,
-    `std::allocator`)
+For example: not std::is_same<void, T>::value and has_value_type<T>::value
+will not compile when T = void (on MSVC at least). Whereas
+conjunction<negation<std::is_same<void, T>>, has_value_type<T>>::value will
+stop evaluating if negation<...>::value == false
 
-    #### Default type
+Please note that those constructs must be used with caution, since symbols can
+become very long quickly (which can slow down compilation and cause MSVC
+internal compiler errors). Only use it when you have to (see example ahead).
+*/
+template<class...> struct conjunction : std::true_type {};
+template<class B1> struct conjunction<B1> : B1 {};
+template<class B1, class... Bn>
+struct conjunction<B1, Bn...> : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
 
-    With the default values for @a ObjectType (`std::map`), @a StringType
-    (`std::string`), and @a AllocatorType (`std::allocator`), the default
-    value for @a object_t is:
+template<class B> struct negation : std::integral_constant < bool, !B::value > {};
 
-    @code {.cpp}
-    std::map<
-      std::string, // key_type
-      basic_json, // value_type
-      std::less<std::string>, // key_compare
-      std::allocator<std::pair<const std::string, basic_json>> // allocator_type
-    >
-    @endcode
+// dispatch utility (taken from ranges-v3)
+template<unsigned N> struct priority_tag : priority_tag < N - 1 > {};
+template<> struct priority_tag<0> {};
 
-    #### Behavior
 
-    The choice of @a object_t influences the behavior of the JSON class. With
-    the default type, objects have the following behavior:
+//////////////////
+// constructors //
+//////////////////
 
-    - When all names are unique, objects will be interoperable in the sense
-      that all software implementations receiving that object will agree on
-      the name-value mappings.
-    - When the names within an object are not unique, later stored name/value
-      pairs overwrite previously stored name/value pairs, leaving the used
-      names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will
-      be treated as equal and both stored as `{"key": 1}`.
-    - Internally, name/value pairs are stored in lexicographical order of the
-      names. Objects will also be serialized (see @ref dump) in this order.
-      For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored
-      and serialized as `{"a": 2, "b": 1}`.
-    - When comparing objects, the order of the name/value pairs is irrelevant.
-      This makes objects interoperable in the sense that they will not be
-      affected by these differences. For instance, `{"b": 1, "a": 2}` and
-      `{"a": 2, "b": 1}` will be treated as equal.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the maximum depth of nesting.
-
-    In this class, the object's limit of nesting is not constraint explicitly.
-    However, a maximum depth of nesting may be introduced by the compiler or
-    runtime environment. A theoretical limit can be queried by calling the
-    @ref max_size function of a JSON object.
+template<value_t> struct external_constructor;
 
-    #### Storage
-
-    Objects are stored as pointers in a @ref basic_json type. That is, for any
-    access to object values, a pointer of type `object_t*` must be
-    dereferenced.
+template<>
+struct external_constructor<value_t::boolean>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept
+    {
+        j.m_type = value_t::boolean;
+        j.m_value = b;
+        j.assert_invariant();
+    }
+};
 
-    @sa @ref array_t -- type for an array value
+template<>
+struct external_constructor<value_t::string>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const typename BasicJsonType::string_t& s)
+    {
+        j.m_type = value_t::string;
+        j.m_value = s;
+        j.assert_invariant();
+    }
+};
 
-    @since version 1.0.0
+template<>
+struct external_constructor<value_t::number_float>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
+    {
+        j.m_type = value_t::number_float;
+        j.m_value = val;
+        j.assert_invariant();
+    }
+};
 
-    @note The order name/value pairs are added to the object is *not*
-    preserved by the library. Therefore, iterating an object may return
-    name/value pairs in a different order than they were originally stored. In
-    fact, keys will be traversed in alphabetical order as `std::map` with
-    `std::less` is used by default. Please note this behavior conforms to [RFC
-    7159](http://rfc7159.net/rfc7159), because any order implements the
-    specified "unordered" nature of JSON objects.
-    */
-    using object_t = ObjectType<StringType,
-          basic_json,
-          std::less<StringType>,
-          AllocatorType<std::pair<const StringType,
-          basic_json>>>;
+template<>
+struct external_constructor<value_t::number_unsigned>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::number_unsigned_t val) noexcept
+    {
+        j.m_type = value_t::number_unsigned;
+        j.m_value = val;
+        j.assert_invariant();
+    }
+};
 
-    /*!
-    @brief a type for an array
+template<>
+struct external_constructor<value_t::number_integer>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::number_integer_t val) noexcept
+    {
+        j.m_type = value_t::number_integer;
+        j.m_value = val;
+        j.assert_invariant();
+    }
+};
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
-    > An array is an ordered sequence of zero or more values.
+template<>
+struct external_constructor<value_t::array>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const typename BasicJsonType::array_t& arr)
+    {
+        j.m_type = value_t::array;
+        j.m_value = arr;
+        j.assert_invariant();
+    }
 
-    To store objects in C++, a type is defined by the template parameters
-    explained below.
+    template<typename BasicJsonType, typename CompatibleArrayType,
+             enable_if_t<not std::is_same<CompatibleArrayType,
+                                          typename BasicJsonType::array_t>::value,
+                         int> = 0>
+    static void construct(BasicJsonType& j, const CompatibleArrayType& arr)
+    {
+        using std::begin;
+        using std::end;
+        j.m_type = value_t::array;
+        j.m_value.array = j.template create<typename BasicJsonType::array_t>(begin(arr), end(arr));
+        j.assert_invariant();
+    }
 
-    @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
-    `std::list`)
-    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const std::vector<bool>& arr)
+    {
+        j.m_type = value_t::array;
+        j.m_value = value_t::array;
+        j.m_value.array->reserve(arr.size());
+        for (bool x : arr)
+        {
+            j.m_value.array->push_back(x);
+        }
+        j.assert_invariant();
+    }
+};
 
-    #### Default type
+template<>
+struct external_constructor<value_t::object>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const typename BasicJsonType::object_t& obj)
+    {
+        j.m_type = value_t::object;
+        j.m_value = obj;
+        j.assert_invariant();
+    }
 
-    With the default values for @a ArrayType (`std::vector`) and @a
-    AllocatorType (`std::allocator`), the default value for @a array_t is:
+    template<typename BasicJsonType, typename CompatibleObjectType,
+             enable_if_t<not std::is_same<CompatibleObjectType,
+                                          typename BasicJsonType::object_t>::value,
+                         int> = 0>
+    static void construct(BasicJsonType& j, const CompatibleObjectType& obj)
+    {
+        using std::begin;
+        using std::end;
 
-    @code {.cpp}
-    std::vector<
-      basic_json, // value_type
-      std::allocator<basic_json> // allocator_type
-    >
-    @endcode
+        j.m_type = value_t::object;
+        j.m_value.object = j.template create<typename BasicJsonType::object_t>(begin(obj), end(obj));
+        j.assert_invariant();
+    }
+};
 
-    #### Limits
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the maximum depth of nesting.
+////////////////////////
+// has_/is_ functions //
+////////////////////////
 
-    In this class, the array's limit of nesting is not constraint explicitly.
-    However, a maximum depth of nesting may be introduced by the compiler or
-    runtime environment. A theoretical limit can be queried by calling the
-    @ref max_size function of a JSON array.
+/*!
+@brief Helper to determine whether there's a key_type for T.
 
-    #### Storage
+This helper is used to tell associative containers apart from other containers
+such as sequence containers. For instance, `std::map` passes the test as it
+contains a `mapped_type`, whereas `std::vector` fails the test.
 
-    Arrays are stored as pointers in a @ref basic_json type. That is, for any
-    access to array values, a pointer of type `array_t*` must be dereferenced.
+@sa http://stackoverflow.com/a/7728728/266378
+@since version 1.0.0, overworked in version 2.0.6
+*/
+#define NLOHMANN_JSON_HAS_HELPER(type)                                        \
+    template<typename T> struct has_##type {                                  \
+    private:                                                                  \
+        template<typename U, typename = typename U::type>                     \
+        static int detect(U &&);                                              \
+        static void detect(...);                                              \
+    public:                                                                   \
+        static constexpr bool value =                                         \
+                std::is_integral<decltype(detect(std::declval<T>()))>::value; \
+    }
 
-    @sa @ref object_t -- type for an object value
+NLOHMANN_JSON_HAS_HELPER(mapped_type);
+NLOHMANN_JSON_HAS_HELPER(key_type);
+NLOHMANN_JSON_HAS_HELPER(value_type);
+NLOHMANN_JSON_HAS_HELPER(iterator);
 
-    @since version 1.0.0
-    */
-    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
+#undef NLOHMANN_JSON_HAS_HELPER
 
-    /*!
-    @brief a type for a string
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
-    > A string is a sequence of zero or more Unicode characters.
+template<bool B, class RealType, class CompatibleObjectType>
+struct is_compatible_object_type_impl : std::false_type {};
 
-    To store objects in C++, a type is defined by the template parameter
-    described below. Unicode values are split by the JSON class into
-    byte-sized characters during deserialization.
+template<class RealType, class CompatibleObjectType>
+struct is_compatible_object_type_impl<true, RealType, CompatibleObjectType>
+{
+    static constexpr auto value =
+        std::is_constructible<typename RealType::key_type,
+        typename CompatibleObjectType::key_type>::value and
+        std::is_constructible<typename RealType::mapped_type,
+        typename CompatibleObjectType::mapped_type>::value;
+};
 
-    @tparam StringType  the container to store strings (e.g., `std::string`).
-    Note this container is used for keys/names in objects, see @ref object_t.
+template<class BasicJsonType, class CompatibleObjectType>
+struct is_compatible_object_type
+{
+    static auto constexpr value = is_compatible_object_type_impl <
+                                  conjunction<negation<std::is_same<void, CompatibleObjectType>>,
+                                  has_mapped_type<CompatibleObjectType>,
+                                  has_key_type<CompatibleObjectType>>::value,
+                                  typename BasicJsonType::object_t, CompatibleObjectType >::value;
+};
 
-    #### Default type
+template<typename BasicJsonType, typename T>
+struct is_basic_json_nested_type
+{
+    static auto constexpr value = std::is_same<T, typename BasicJsonType::iterator>::value or
+                                  std::is_same<T, typename BasicJsonType::const_iterator>::value or
+                                  std::is_same<T, typename BasicJsonType::reverse_iterator>::value or
+                                  std::is_same<T, typename BasicJsonType::const_reverse_iterator>::value or
+                                  std::is_same<T, typename BasicJsonType::json_pointer>::value;
+};
 
-    With the default values for @a StringType (`std::string`), the default
-    value for @a string_t is:
+template<class BasicJsonType, class CompatibleArrayType>
+struct is_compatible_array_type
+{
+    static auto constexpr value =
+        conjunction<negation<std::is_same<void, CompatibleArrayType>>,
+        negation<is_compatible_object_type<
+        BasicJsonType, CompatibleArrayType>>,
+        negation<std::is_constructible<typename BasicJsonType::string_t,
+        CompatibleArrayType>>,
+        negation<is_basic_json_nested_type<BasicJsonType, CompatibleArrayType>>,
+        has_value_type<CompatibleArrayType>,
+        has_iterator<CompatibleArrayType>>::value;
+};
 
-    @code {.cpp}
-    std::string
-    @endcode
+template<bool, typename, typename>
+struct is_compatible_integer_type_impl : std::false_type {};
 
-    #### String comparison
+template<typename RealIntegerType, typename CompatibleNumberIntegerType>
+struct is_compatible_integer_type_impl<true, RealIntegerType, CompatibleNumberIntegerType>
+{
+    // is there an assert somewhere on overflows?
+    using RealLimits = std::numeric_limits<RealIntegerType>;
+    using CompatibleLimits = std::numeric_limits<CompatibleNumberIntegerType>;
+
+    static constexpr auto value =
+        std::is_constructible<RealIntegerType,
+        CompatibleNumberIntegerType>::value and
+        CompatibleLimits::is_integer and
+        RealLimits::is_signed == CompatibleLimits::is_signed;
+};
 
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
-    > Software implementations are typically required to test names of object
-    > members for equality. Implementations that transform the textual
-    > representation into sequences of Unicode code units and then perform the
-    > comparison numerically, code unit by code unit, are interoperable in the
-    > sense that implementations will agree in all cases on equality or
-    > inequality of two strings. For example, implementations that compare
-    > strings with escaped characters unconverted may incorrectly find that
-    > `"a\\b"` and `"a\u005Cb"` are not equal.
+template<typename RealIntegerType, typename CompatibleNumberIntegerType>
+struct is_compatible_integer_type
+{
+    static constexpr auto value =
+        is_compatible_integer_type_impl <
+        std::is_integral<CompatibleNumberIntegerType>::value and
+        not std::is_same<bool, CompatibleNumberIntegerType>::value,
+        RealIntegerType, CompatibleNumberIntegerType > ::value;
+};
 
-    This implementation is interoperable as it does compare strings code unit
-    by code unit.
 
-    #### Storage
+// trait checking if JSONSerializer<T>::from_json(json const&, udt&) exists
+template<typename BasicJsonType, typename T>
+struct has_from_json
+{
+  private:
+    // also check the return type of from_json
+    template<typename U, typename = enable_if_t<std::is_same<void, decltype(uncvref_t<U>::from_json(
+                 std::declval<BasicJsonType>(), std::declval<T&>()))>::value>>
+    static int detect(U&&);
+    static void detect(...);
 
-    String values are stored as pointers in a @ref basic_json type. That is,
-    for any access to string values, a pointer of type `string_t*` must be
-    dereferenced.
+  public:
+    static constexpr bool value = std::is_integral<decltype(
+                                      detect(std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value;
+};
 
-    @since version 1.0.0
-    */
-    using string_t = StringType;
+// This trait checks if JSONSerializer<T>::from_json(json const&) exists
+// this overload is used for non-default-constructible user-defined-types
+template<typename BasicJsonType, typename T>
+struct has_non_default_from_json
+{
+  private:
+    template <
+        typename U,
+        typename = enable_if_t<std::is_same<
+                                   T, decltype(uncvref_t<U>::from_json(std::declval<BasicJsonType>()))>::value >>
+    static int detect(U&&);
+    static void detect(...);
 
-    /*!
-    @brief a type for a boolean
+  public:
+    static constexpr bool value = std::is_integral<decltype(detect(
+                                      std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value;
+};
 
-    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
-    type which differentiates the two literals `true` and `false`.
+// This trait checks if BasicJsonType::json_serializer<T>::to_json exists
+template<typename BasicJsonType, typename T>
+struct has_to_json
+{
+  private:
+    template<typename U, typename = decltype(uncvref_t<U>::to_json(
+                 std::declval<BasicJsonType&>(), std::declval<T>()))>
+    static int detect(U&&);
+    static void detect(...);
 
-    To store objects in C++, a type is defined by the template parameter @a
-    BooleanType which chooses the type to use.
+  public:
+    static constexpr bool value = std::is_integral<decltype(detect(
+                                      std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value;
+};
 
-    #### Default type
 
-    With the default values for @a BooleanType (`bool`), the default value for
-    @a boolean_t is:
+/////////////
+// to_json //
+/////////////
 
-    @code {.cpp}
-    bool
-    @endcode
+template<typename BasicJsonType, typename T, enable_if_t<
+             std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
+void to_json(BasicJsonType& j, T b) noexcept
+{
+    external_constructor<value_t::boolean>::construct(j, b);
+}
 
-    #### Storage
+template<typename BasicJsonType, typename CompatibleString,
+         enable_if_t<std::is_constructible<typename BasicJsonType::string_t,
+                     CompatibleString>::value, int> = 0>
+void to_json(BasicJsonType& j, const CompatibleString& s)
+{
+    external_constructor<value_t::string>::construct(j, s);
+}
 
-    Boolean values are stored directly inside a @ref basic_json type.
+template<typename BasicJsonType, typename FloatType,
+         enable_if_t<std::is_floating_point<FloatType>::value, int> = 0>
+void to_json(BasicJsonType& j, FloatType val) noexcept
+{
+    external_constructor<value_t::number_float>::construct(j, static_cast<typename BasicJsonType::number_float_t>(val));
+}
 
-    @since version 1.0.0
-    */
-    using boolean_t = BooleanType;
+template <
+    typename BasicJsonType, typename CompatibleNumberUnsignedType,
+    enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t,
+                CompatibleNumberUnsignedType>::value, int> = 0 >
+void to_json(BasicJsonType& j, CompatibleNumberUnsignedType val) noexcept
+{
+    external_constructor<value_t::number_unsigned>::construct(j, static_cast<typename BasicJsonType::number_unsigned_t>(val));
+}
 
-    /*!
-    @brief a type for a number (integer)
+template <
+    typename BasicJsonType, typename CompatibleNumberIntegerType,
+    enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t,
+                CompatibleNumberIntegerType>::value, int> = 0 >
+void to_json(BasicJsonType& j, CompatibleNumberIntegerType val) noexcept
+{
+    external_constructor<value_t::number_integer>::construct(j, static_cast<typename BasicJsonType::number_integer_t>(val));
+}
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
+template<typename BasicJsonType, typename EnumType,
+         enable_if_t<std::is_enum<EnumType>::value, int> = 0>
+void to_json(BasicJsonType& j, EnumType e) noexcept
+{
+    using underlying_type = typename std::underlying_type<EnumType>::type;
+    external_constructor<value_t::number_integer>::construct(j, static_cast<underlying_type>(e));
+}
 
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, const std::vector<bool>& e)
+{
+    external_constructor<value_t::array>::construct(j, e);
+}
 
-    To store integer numbers in C++, a type is defined by the template
-    parameter @a NumberIntegerType which chooses the type to use.
+template <
+    typename BasicJsonType, typename CompatibleArrayType,
+    enable_if_t <
+        is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value or
+        std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value,
+        int > = 0 >
+void to_json(BasicJsonType& j, const  CompatibleArrayType& arr)
+{
+    external_constructor<value_t::array>::construct(j, arr);
+}
 
-    #### Default type
+template <
+    typename BasicJsonType, typename CompatibleObjectType,
+    enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value,
+                int> = 0 >
+void to_json(BasicJsonType& j, const  CompatibleObjectType& arr)
+{
+    external_constructor<value_t::object>::construct(j, arr);
+}
 
-    With the default values for @a NumberIntegerType (`int64_t`), the default
-    value for @a number_integer_t is:
+template <typename BasicJsonType, typename T, std::size_t N,
+          enable_if_t<not std::is_constructible<
+                          typename BasicJsonType::string_t, T (&)[N]>::value,
+                      int> = 0>
+void to_json(BasicJsonType& j, T (&arr)[N])
+{
+    external_constructor<value_t::array>::construct(j, arr);
+}
 
-    @code {.cpp}
-    int64_t
-    @endcode
+///////////////
+// from_json //
+///////////////
+
+// overloads for basic_json template parameters
+template<typename BasicJsonType, typename ArithmeticType,
+         enable_if_t<std::is_arithmetic<ArithmeticType>::value and
+                     not std::is_same<ArithmeticType,
+                                      typename BasicJsonType::boolean_t>::value,
+                     int> = 0>
+void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
+{
+    switch (static_cast<value_t>(j))
+    {
+        case value_t::number_unsigned:
+        {
+            val = static_cast<ArithmeticType>(
+                      *j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
+            break;
+        }
+        case value_t::number_integer:
+        {
+            val = static_cast<ArithmeticType>(
+                      *j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
+            break;
+        }
+        case value_t::number_float:
+        {
+            val = static_cast<ArithmeticType>(
+                      *j.template get_ptr<const typename BasicJsonType::number_float_t*>());
+            break;
+        }
+        default:
+        {
+            JSON_THROW(type_error::create(302, "type must be number, but is " + j.type_name()));
+        }
+    }
+}
 
-    #### Default behavior
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
+{
+    if (not j.is_boolean())
+    {
+        JSON_THROW(type_error::create(302, "type must be boolean, but is " + j.type_name()));
+    }
+    b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
+}
 
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in integer literals lead to an interpretation as octal
-      number. Internally, the value will be stored as decimal number. For
-      instance, the C++ integer literal `010` will be serialized to `8`.
-      During deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s)
+{
+    if (not j.is_string())
+    {
+        JSON_THROW(type_error::create(302, "type must be string, but is " + j.type_name()));
+    }
+    s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
+}
 
-    #### Limits
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::number_float_t& val)
+{
+    get_arithmetic_value(j, val);
+}
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the range and precision of numbers.
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val)
+{
+    get_arithmetic_value(j, val);
+}
 
-    When the default type is used, the maximal integer number that can be
-    stored is `9223372036854775807` (INT64_MAX) and the minimal integer number
-    that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers
-    that are out of range will yield over/underflow when used in a
-    constructor. During deserialization, too large or small integer numbers
-    will be automatically be stored as @ref number_unsigned_t or @ref
-    number_float_t.
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::number_integer_t& val)
+{
+    get_arithmetic_value(j, val);
+}
 
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
-    > Note that when such software is used, numbers that are integers and are
-    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
-    > that implementations will agree exactly on their numeric values.
+template<typename BasicJsonType, typename EnumType,
+         enable_if_t<std::is_enum<EnumType>::value, int> = 0>
+void from_json(const BasicJsonType& j, EnumType& e)
+{
+    typename std::underlying_type<EnumType>::type val;
+    get_arithmetic_value(j, val);
+    e = static_cast<EnumType>(val);
+}
 
-    As this range is a subrange of the exactly supported range [INT64_MIN,
-    INT64_MAX], this class's integer type is interoperable.
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::array_t& arr)
+{
+    if (not j.is_array())
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + j.type_name()));
+    }
+    arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
+}
 
-    #### Storage
+// forward_list doesn't have an insert method
+template<typename BasicJsonType, typename T, typename Allocator,
+         enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
+void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
+{
+    if (not j.is_array())
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + j.type_name()));
+    }
 
-    Integer number values are stored directly inside a @ref basic_json type.
+    for (auto it = j.rbegin(), end = j.rend(); it != end; ++it)
+    {
+        l.push_front(it->template get<T>());
+    }
+}
 
-    @sa @ref number_float_t -- type for number values (floating-point)
+template<typename BasicJsonType, typename CompatibleArrayType>
+void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<0>)
+{
+    using std::begin;
+    using std::end;
 
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+    std::transform(j.begin(), j.end(),
+                   std::inserter(arr, end(arr)), [](const BasicJsonType & i)
+    {
+        // get<BasicJsonType>() returns *this, this won't call a from_json
+        // method when value_type is BasicJsonType
+        return i.template get<typename CompatibleArrayType::value_type>();
+    });
+}
 
-    @since version 1.0.0
-    */
-    using number_integer_t = NumberIntegerType;
+template<typename BasicJsonType, typename CompatibleArrayType>
+auto from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<1>)
+-> decltype(
+    arr.reserve(std::declval<typename CompatibleArrayType::size_type>()),
+    void())
+{
+    using std::begin;
+    using std::end;
 
-    /*!
-    @brief a type for a number (unsigned)
+    arr.reserve(j.size());
+    std::transform(j.begin(), j.end(),
+                   std::inserter(arr, end(arr)), [](const BasicJsonType & i)
+    {
+        // get<BasicJsonType>() returns *this, this won't call a from_json
+        // method when value_type is BasicJsonType
+        return i.template get<typename CompatibleArrayType::value_type>();
+    });
+}
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
+template<typename BasicJsonType, typename CompatibleArrayType,
+         enable_if_t<is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value and
+                     std::is_convertible<BasicJsonType, typename CompatibleArrayType::value_type>::value and
+                     not std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value, int> = 0>
+void from_json(const BasicJsonType& j, CompatibleArrayType& arr)
+{
+    if (not j.is_array())
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + j.type_name()));
+    }
 
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
+    from_json_array_impl(j, arr, priority_tag<1> {});
+}
 
-    To store unsigned integer numbers in C++, a type is defined by the
-    template parameter @a NumberUnsignedType which chooses the type to use.
+template<typename BasicJsonType, typename CompatibleObjectType,
+         enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value, int> = 0>
+void from_json(const BasicJsonType& j, CompatibleObjectType& obj)
+{
+    if (not j.is_object())
+    {
+        JSON_THROW(type_error::create(302, "type must be object, but is " + j.type_name()));
+    }
 
-    #### Default type
+    auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
+    using std::begin;
+    using std::end;
+    // we could avoid the assignment, but this might require a for loop, which
+    // might be less efficient than the container constructor for some
+    // containers (would it?)
+    obj = CompatibleObjectType(begin(*inner_object), end(*inner_object));
+}
 
-    With the default values for @a NumberUnsignedType (`uint64_t`), the
-    default value for @a number_unsigned_t is:
+// overload for arithmetic types, not chosen for basic_json template arguments
+// (BooleanType, etc..); note: Is it really necessary to provide explicit
+// overloads for boolean_t etc. in case of a custom BooleanType which is not
+// an arithmetic type?
+template<typename BasicJsonType, typename ArithmeticType,
+         enable_if_t <
+             std::is_arithmetic<ArithmeticType>::value and
+             not std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value and
+             not std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value and
+             not std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value and
+             not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
+             int> = 0>
+void from_json(const BasicJsonType& j, ArithmeticType& val)
+{
+    switch (static_cast<value_t>(j))
+    {
+        case value_t::number_unsigned:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
+            break;
+        }
+        case value_t::number_integer:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
+            break;
+        }
+        case value_t::number_float:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
+            break;
+        }
+        case value_t::boolean:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>());
+            break;
+        }
+        default:
+        {
+            JSON_THROW(type_error::create(302, "type must be number, but is " + j.type_name()));
+        }
+    }
+}
 
-    @code {.cpp}
-    uint64_t
-    @endcode
+struct to_json_fn
+{
+  private:
+    template<typename BasicJsonType, typename T>
+    auto call(BasicJsonType& j, T&& val, priority_tag<1>) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
+    -> decltype(to_json(j, std::forward<T>(val)), void())
+    {
+        return to_json(j, std::forward<T>(val));
+    }
 
-    #### Default behavior
+    template<typename BasicJsonType, typename T>
+    void call(BasicJsonType&, T&&, priority_tag<0>) const noexcept
+    {
+        static_assert(sizeof(BasicJsonType) == 0,
+                      "could not find to_json() method in T's namespace");
+    }
 
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in integer literals lead to an interpretation as octal
-      number. Internally, the value will be stored as decimal number. For
-      instance, the C++ integer literal `010` will be serialized to `8`.
-      During deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
+  public:
+    template<typename BasicJsonType, typename T>
+    void operator()(BasicJsonType& j, T&& val) const
+    noexcept(noexcept(std::declval<to_json_fn>().call(j, std::forward<T>(val), priority_tag<1> {})))
+    {
+        return call(j, std::forward<T>(val), priority_tag<1> {});
+    }
+};
 
-    #### Limits
+struct from_json_fn
+{
+  private:
+    template<typename BasicJsonType, typename T>
+    auto call(const BasicJsonType& j, T& val, priority_tag<1>) const
+    noexcept(noexcept(from_json(j, val)))
+    -> decltype(from_json(j, val), void())
+    {
+        return from_json(j, val);
+    }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the range and precision of numbers.
+    template<typename BasicJsonType, typename T>
+    void call(const BasicJsonType&, T&, priority_tag<0>) const noexcept
+    {
+        static_assert(sizeof(BasicJsonType) == 0,
+                      "could not find from_json() method in T's namespace");
+    }
 
-    When the default type is used, the maximal integer number that can be
-    stored is `18446744073709551615` (UINT64_MAX) and the minimal integer
-    number that can be stored is `0`. Integer numbers that are out of range
-    will yield over/underflow when used in a constructor. During
-    deserialization, too large or small integer numbers will be automatically
-    be stored as @ref number_integer_t or @ref number_float_t.
+  public:
+    template<typename BasicJsonType, typename T>
+    void operator()(const BasicJsonType& j, T& val) const
+    noexcept(noexcept(std::declval<from_json_fn>().call(j, val, priority_tag<1> {})))
+    {
+        return call(j, val, priority_tag<1> {});
+    }
+};
 
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
-    > Note that when such software is used, numbers that are integers and are
-    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
-    > that implementations will agree exactly on their numeric values.
+// taken from ranges-v3
+template<typename T>
+struct static_const
+{
+    static constexpr T value{};
+};
 
-    As this range is a subrange (when considered in conjunction with the
-    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
-    this class's integer type is interoperable.
+template<typename T>
+constexpr T static_const<T>::value;
+} // namespace detail
 
-    #### Storage
 
-    Integer number values are stored directly inside a @ref basic_json type.
+/// namespace to hold default `to_json` / `from_json` functions
+namespace
+{
+constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value;
+constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
+}
 
-    @sa @ref number_float_t -- type for number values (floating-point)
-    @sa @ref number_integer_t -- type for number values (integer)
 
-    @since version 2.0.0
-    */
-    using number_unsigned_t = NumberUnsignedType;
+/*!
+@brief default JSONSerializer template argument
 
+This serializer ignores the template arguments and uses ADL
+([argument-dependent lookup](http://en.cppreference.com/w/cpp/language/adl))
+for serialization.
+*/
+template<typename = void, typename = void>
+struct adl_serializer
+{
     /*!
-    @brief a type for a number (floating-point)
-
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
-
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
-
-    To store floating-point numbers in C++, a type is defined by the template
-    parameter @a NumberFloatType which chooses the type to use.
-
-    #### Default type
-
-    With the default values for @a NumberFloatType (`double`), the default
-    value for @a number_float_t is:
-
-    @code {.cpp}
-    double
-    @endcode
-
-    #### Default behavior
-
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in floating-point literals will be ignored. Internally,
-      the value will be stored as decimal number. For instance, the C++
-      floating-point literal `01.2` will be serialized to `1.2`. During
-      deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
-
-    #### Limits
-
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
-    > This specification allows implementations to set limits on the range and
-    > precision of numbers accepted. Since software that implements IEEE
-    > 754-2008 binary64 (double precision) numbers is generally available and
-    > widely used, good interoperability can be achieved by implementations
-    > that expect no more precision or range than these provide, in the sense
-    > that implementations will approximate JSON numbers within the expected
-    > precision.
-
-    This implementation does exactly follow this approach, as it uses double
-    precision floating-point numbers. Note values smaller than
-    `-1.79769313486232e+308` and values greater than `1.79769313486232e+308`
-    will be stored as NaN internally and be serialized to `null`.
-
-    #### Storage
-
-    Floating-point number values are stored directly inside a @ref basic_json
-    type.
-
-    @sa @ref number_integer_t -- type for number values (integer)
+    @brief convert a JSON value to any value type
 
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+    This function is usually called by the `get()` function of the
+    @ref basic_json class (either explicit or via conversion operators).
 
-    @since version 1.0.0
+    @param[in] j         JSON value to read from
+    @param[in,out] val  value to write to
     */
-    using number_float_t = NumberFloatType;
-
-    /// @}
-
-
-    ///////////////////////////
-    // JSON type enumeration //
-    ///////////////////////////
+    template<typename BasicJsonType, typename ValueType>
+    static void from_json(BasicJsonType&& j, ValueType& val) noexcept(
+        noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), val)))
+    {
+        ::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
+    }
 
     /*!
-    @brief the JSON type enumeration
+    @brief convert any value type to a JSON value
 
-    This enumeration collects the different JSON types. It is internally used
-    to distinguish the stored values, and the functions @ref is_null(), @ref
-    is_object(), @ref is_array(), @ref is_string(), @ref is_boolean(), @ref
-    is_number() (with @ref is_number_integer(), @ref is_number_unsigned(), and
-    @ref is_number_float()), @ref is_discarded(), @ref is_primitive(), and
-    @ref is_structured() rely on it.
+    This function is usually called by the constructors of the @ref basic_json
+    class.
 
-    @note There are three enumeration entries (number_integer,
-    number_unsigned, and number_float), because the library distinguishes
-    these three types for numbers: @ref number_unsigned_t is used for unsigned
-    integers, @ref number_integer_t is used for signed integers, and @ref
-    number_float_t is used for floating-point numbers or to approximate
-    integers which do not fit in the limits of their respective type.
+    @param[in,out] j  JSON value to write to
+    @param[in] val     value to read from
+    */
+    template<typename BasicJsonType, typename ValueType>
+    static void to_json(BasicJsonType& j, ValueType&& val) noexcept(
+        noexcept(::nlohmann::to_json(j, std::forward<ValueType>(val))))
+    {
+        ::nlohmann::to_json(j, std::forward<ValueType>(val));
+    }
+};
 
-    @sa @ref basic_json(const value_t value_type) -- create a JSON value with
-    the default value for a given type
 
-    @since version 1.0.0
-    */
-    enum class value_t : uint8_t
-    {
-        null,            ///< null value
-        object,          ///< object (unordered set of name/value pairs)
-        array,           ///< array (ordered collection of values)
-        string,          ///< string value
-        boolean,         ///< boolean value
-        number_integer,  ///< number value (signed integer)
-        number_unsigned, ///< number value (unsigned integer)
-        number_float,    ///< number value (floating-point)
-        discarded        ///< discarded by the the parser callback function
-    };
+/*!
+@brief a class to store JSON values
+
+@tparam ObjectType type for JSON objects (`std::map` by default; will be used
+in @ref object_t)
+@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
+in @ref array_t)
+@tparam StringType type for JSON strings and object keys (`std::string` by
+default; will be used in @ref string_t)
+@tparam BooleanType type for JSON booleans (`bool` by default; will be used
+in @ref boolean_t)
+@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
+default; will be used in @ref number_integer_t)
+@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
+`uint64_t` by default; will be used in @ref number_unsigned_t)
+@tparam NumberFloatType type for JSON floating-point numbers (`double` by
+default; will be used in @ref number_float_t)
+@tparam AllocatorType type of the allocator to use (`std::allocator` by
+default)
+@tparam JSONSerializer the serializer to resolve internal calls to `to_json()`
+and `from_json()` (@ref adl_serializer by default)
+
+@requirement The class satisfies the following concept requirements:
+- Basic
+ - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
+   JSON values can be default constructed. The result will be a JSON null
+   value.
+ - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
+   A JSON value can be constructed from an rvalue argument.
+ - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
+   A JSON value can be copy-constructed from an lvalue expression.
+ - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
+   A JSON value van be assigned from an rvalue argument.
+ - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
+   A JSON value can be copy-assigned from an lvalue expression.
+ - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
+   JSON values can be destructed.
+- Layout
+ - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
+   JSON values have
+   [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
+   All non-static data members are private and standard layout types, the
+   class has no virtual functions or (virtual) base classes.
+- Library-wide
+ - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
+   JSON values can be compared with `==`, see @ref
+   operator==(const_reference,const_reference).
+ - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
+   JSON values can be compared with `<`, see @ref
+   operator<(const_reference,const_reference).
+ - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
+   Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
+   other compatible types, using unqualified function call @ref swap().
+ - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
+   JSON values can be compared against `std::nullptr_t` objects which are used
+   to model the `null` value.
+- Container
+ - [Container](http://en.cppreference.com/w/cpp/concept/Container):
+   JSON values can be used like STL containers and provide iterator access.
+ - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
+   JSON values can be used like STL containers and provide reverse iterator
+   access.
 
+@invariant The member variables @a m_value and @a m_type have the following
+relationship:
+- If `m_type == value_t::object`, then `m_value.object != nullptr`.
+- If `m_type == value_t::array`, then `m_value.array != nullptr`.
+- If `m_type == value_t::string`, then `m_value.string != nullptr`.
+The invariants are checked by member function assert_invariant().
+
+@internal
+@note ObjectType trick from http://stackoverflow.com/a/9860911
+@endinternal
+
+@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
+Format](http://rfc7159.net/rfc7159)
+
+@since version 1.0.0
 
+@nosubgrouping
+*/
+template <
+    template<typename U, typename V, typename... Args> class ObjectType = std::map,
+    template<typename U, typename... Args> class ArrayType = std::vector,
+    class StringType = std::string,
+    class BooleanType = bool,
+    class NumberIntegerType = std::int64_t,
+    class NumberUnsignedType = std::uint64_t,
+    class NumberFloatType = double,
+    template<typename U> class AllocatorType = std::allocator,
+    template<typename T, typename SFINAE = void> class JSONSerializer = adl_serializer
+    >
+class basic_json
+{
   private:
+    template<detail::value_t> friend struct detail::external_constructor;
+    /// workaround type for MSVC
+    using basic_json_t = basic_json<ObjectType, ArrayType, StringType,
+          BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType,
+          AllocatorType, JSONSerializer>;
 
-    /// helper for exception-safe object creation
-    template<typename T, typename... Args>
-    static T* create(Args&& ... args)
+  public:
+    using value_t = detail::value_t;
+    // forward declarations
+    template<typename U> class iter_impl;
+    template<typename Base> class json_reverse_iterator;
+    class json_pointer;
+    template<typename T, typename SFINAE>
+    using json_serializer = JSONSerializer<T, SFINAE>;
+
+
+    ////////////////
+    // exceptions //
+    ////////////////
+
+    /// @name exceptions
+    /// Classes to implement user-defined exceptions.
+    /// @{
+
+    /// @copydoc detail::exception
+    using exception = detail::exception;
+    /// @copydoc detail::parse_error
+    using parse_error = detail::parse_error;
+    /// @copydoc detail::invalid_iterator
+    using invalid_iterator = detail::invalid_iterator;
+    /// @copydoc detail::type_error
+    using type_error = detail::type_error;
+    /// @copydoc detail::out_of_range
+    using out_of_range = detail::out_of_range;
+    /// @copydoc detail::other_error
+    using other_error = detail::other_error;
+
+    /// @}
+
+
+    /////////////////////
+    // container types //
+    /////////////////////
+
+    /// @name container types
+    /// The canonic container types to use @ref basic_json like any other STL
+    /// container.
+    /// @{
+
+    /// the type of elements in a basic_json container
+    using value_type = basic_json;
+
+    /// the type of an element reference
+    using reference = value_type&;
+    /// the type of an element const reference
+    using const_reference = const value_type&;
+
+    /// a type to represent differences between iterators
+    using difference_type = std::ptrdiff_t;
+    /// a type to represent container sizes
+    using size_type = std::size_t;
+
+    /// the allocator type
+    using allocator_type = AllocatorType<basic_json>;
+
+    /// the type of an element pointer
+    using pointer = typename std::allocator_traits<allocator_type>::pointer;
+    /// the type of an element const pointer
+    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
+
+    /// an iterator for a basic_json container
+    using iterator = iter_impl<basic_json>;
+    /// a const iterator for a basic_json container
+    using const_iterator = iter_impl<const basic_json>;
+    /// a reverse iterator for a basic_json container
+    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
+    /// a const reverse iterator for a basic_json container
+    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;
+
+    /// @}
+
+
+    /*!
+    @brief returns the allocator associated with the container
+    */
+    static allocator_type get_allocator()
     {
-        AllocatorType<T> alloc;
-        auto deleter = [&](T * object)
-        {
-            alloc.deallocate(object, 1);
-        };
-        std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
-        alloc.construct(object.get(), std::forward<Args>(args)...);
-        assert(object.get() != nullptr);
-        return object.release();
+        return allocator_type();
     }
 
-    ////////////////////////
-    // JSON value storage //
-    ////////////////////////
-
     /*!
-    @brief a JSON value
+    @brief returns version information on the library
 
-    The actual storage for a JSON value of the @ref basic_json class. This
-    union combines the different storage types for the JSON value types
-    defined in @ref value_t.
+    This function returns a JSON object with information about the library,
+    including the version number and information on the platform and compiler.
 
-    JSON type | value_t type    | used type
-    --------- | --------------- | ------------------------
-    object    | object          | pointer to @ref object_t
-    array     | array           | pointer to @ref array_t
-    string    | string          | pointer to @ref string_t
-    boolean   | boolean         | @ref boolean_t
-    number    | number_integer  | @ref number_integer_t
-    number    | number_unsigned | @ref number_unsigned_t
-    number    | number_float    | @ref number_float_t
-    null      | null            | *no value is stored*
+    @return JSON object holding version information
+    key         | description
+    ----------- | ---------------
+    `compiler`  | Information on the used compiler. It is an object with the following keys: `c++` (the used C++ standard), `family` (the compiler family; possible values are `clang`, `icc`, `gcc`, `ilecpp`, `msvc`, `pgcpp`, `sunpro`, and `unknown`), and `version` (the compiler version).
+    `copyright` | The copyright line for the library as string.
+    `name`      | The name of the library as string.
+    `platform`  | The used platform as string. Possible values are `win32`, `linux`, `apple`, `unix`, and `unknown`.
+    `url`       | The URL of the project as string.
+    `version`   | The version of the library. It is an object with the following keys: `major`, `minor`, and `patch` as defined by [Semantic Versioning](http://semver.org), and `string` (the version string).
 
-    @note Variable-length types (objects, arrays, and strings) are stored as
-    pointers. The size of the union should not exceed 64 bits if the default
-    value types are used.
+    @liveexample{The following code shows an example output of the `meta()`
+    function.,meta}
 
-    @since version 1.0.0
+    @complexity Constant.
+
+    @since 2.1.0
     */
-    union json_value
+    static basic_json meta()
     {
-        /// object (stored with pointer to save storage)
-        object_t* object;
-        /// array (stored with pointer to save storage)
-        array_t* array;
-        /// string (stored with pointer to save storage)
-        string_t* string;
-        /// boolean
-        boolean_t boolean;
-        /// number (integer)
-        number_integer_t number_integer;
-        /// number (unsigned integer)
-        number_unsigned_t number_unsigned;
-        /// number (floating-point)
-        number_float_t number_float;
+        basic_json result;
 
-        /// default constructor (for null values)
-        json_value() = default;
-        /// constructor for booleans
-        json_value(boolean_t v) noexcept : boolean(v) {}
-        /// constructor for numbers (integer)
-        json_value(number_integer_t v) noexcept : number_integer(v) {}
-        /// constructor for numbers (unsigned)
-        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
-        /// constructor for numbers (floating-point)
-        json_value(number_float_t v) noexcept : number_float(v) {}
-        /// constructor for empty values of a given type
-        json_value(value_t t)
+        result["copyright"] = "(C) 2013-2017 Niels Lohmann";
+        result["name"] = "JSON for Modern C++";
+        result["url"] = "https://github.com/nlohmann/json";
+        result["version"] =
         {
-            switch (t)
-            {
-                case value_t::object:
-                {
-                    object = create<object_t>();
-                    break;
-                }
+            {"string", "2.1.1"}, {"major", 2}, {"minor", 1}, {"patch", 1}
+        };
 
-                case value_t::array:
-                {
-                    array = create<array_t>();
-                    break;
-                }
+#ifdef _WIN32
+        result["platform"] = "win32";
+#elif defined __linux__
+        result["platform"] = "linux";
+#elif defined __APPLE__
+        result["platform"] = "apple";
+#elif defined __unix__
+        result["platform"] = "unix";
+#else
+        result["platform"] = "unknown";
+#endif
 
-                case value_t::string:
-                {
-                    string = create<string_t>("");
-                    break;
-                }
+#if defined(__clang__)
+        result["compiler"] = {{"family", "clang"}, {"version", __clang_version__}};
+#elif defined(__ICC) || defined(__INTEL_COMPILER)
+        result["compiler"] = {{"family", "icc"}, {"version", __INTEL_COMPILER}};
+#elif defined(__GNUC__) || defined(__GNUG__)
+        result["compiler"] = {{"family", "gcc"}, {"version", std::to_string(__GNUC__) + "." + std::to_string(__GNUC_MINOR__) + "." + std::to_string(__GNUC_PATCHLEVEL__)}};
+#elif defined(__HP_cc) || defined(__HP_aCC)
+        result["compiler"] = "hp"
+#elif defined(__IBMCPP__)
+        result["compiler"] = {{"family", "ilecpp"}, {"version", __IBMCPP__}};
+#elif defined(_MSC_VER)
+        result["compiler"] = {{"family", "msvc"}, {"version", _MSC_VER}};
+#elif defined(__PGI)
+        result["compiler"] = {{"family", "pgcpp"}, {"version", __PGI}};
+#elif defined(__SUNPRO_CC)
+        result["compiler"] = {{"family", "sunpro"}, {"version", __SUNPRO_CC}};
+#else
+        result["compiler"] = {{"family", "unknown"}, {"version", "unknown"}};
+#endif
 
-                case value_t::boolean:
-                {
-                    boolean = boolean_t(false);
-                    break;
-                }
+#ifdef __cplusplus
+        result["compiler"]["c++"] = std::to_string(__cplusplus);
+#else
+        result["compiler"]["c++"] = "unknown";
+#endif
+        return result;
+    }
 
-                case value_t::number_integer:
-                {
-                    number_integer = number_integer_t(0);
-                    break;
-                }
 
-                case value_t::number_unsigned:
-                {
-                    number_unsigned = number_unsigned_t(0);
-                    break;
-                }
+    ///////////////////////////
+    // JSON value data types //
+    ///////////////////////////
 
-                case value_t::number_float:
-                {
-                    number_float = number_float_t(0.0);
-                    break;
-                }
+    /// @name JSON value data types
+    /// The data types to store a JSON value. These types are derived from
+    /// the template arguments passed to class @ref basic_json.
+    /// @{
 
-                case value_t::null:
-                {
-                    break;
-                }
+    /*!
+    @brief a type for an object
 
-                default:
-                {
-                    if (t == value_t::null)
-                    {
-                        throw std::domain_error("961c151d2e87f2686a955a9be24d316f1362bf21 2.0.10"); // LCOV_EXCL_LINE
-                    }
-                    break;
-                }
-            }
-        }
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
+    > An object is an unordered collection of zero or more name/value pairs,
+    > where a name is a string and a value is a string, number, boolean, null,
+    > object, or array.
 
-        /// constructor for strings
-        json_value(const string_t& value)
-        {
-            string = create<string_t>(value);
-        }
+    To store objects in C++, a type is defined by the template parameters
+    described below.
 
-        /// constructor for objects
-        json_value(const object_t& value)
-        {
-            object = create<object_t>(value);
-        }
+    @tparam ObjectType  the container to store objects (e.g., `std::map` or
+    `std::unordered_map`)
+    @tparam StringType the type of the keys or names (e.g., `std::string`).
+    The comparison function `std::less<StringType>` is used to order elements
+    inside the container.
+    @tparam AllocatorType the allocator to use for objects (e.g.,
+    `std::allocator`)
 
-        /// constructor for arrays
-        json_value(const array_t& value)
-        {
-            array = create<array_t>(value);
-        }
-    };
+    #### Default type
 
-    /*!
-    @brief checks the class invariants
+    With the default values for @a ObjectType (`std::map`), @a StringType
+    (`std::string`), and @a AllocatorType (`std::allocator`), the default
+    value for @a object_t is:
 
-    This function asserts the class invariants. It needs to be called at the
-    end of every constructor to make sure that created objects respect the
-    invariant. Furthermore, it has to be called each time the type of a JSON
-    value is changed, because the invariant expresses a relationship between
-    @a m_type and @a m_value.
-    */
-    void assert_invariant() const
-    {
-        assert(m_type != value_t::object or m_value.object != nullptr);
-        assert(m_type != value_t::array or m_value.array != nullptr);
-        assert(m_type != value_t::string or m_value.string != nullptr);
-    }
+    @code {.cpp}
+    std::map<
+      std::string, // key_type
+      basic_json, // value_type
+      std::less<std::string>, // key_compare
+      std::allocator<std::pair<const std::string, basic_json>> // allocator_type
+    >
+    @endcode
 
-  public:
-    //////////////////////////
-    // JSON parser callback //
-    //////////////////////////
+    #### Behavior
 
-    /*!
-    @brief JSON callback events
+    The choice of @a object_t influences the behavior of the JSON class. With
+    the default type, objects have the following behavior:
 
-    This enumeration lists the parser events that can trigger calling a
-    callback function of type @ref parser_callback_t during parsing.
+    - When all names are unique, objects will be interoperable in the sense
+      that all software implementations receiving that object will agree on
+      the name-value mappings.
+    - When the names within an object are not unique, later stored name/value
+      pairs overwrite previously stored name/value pairs, leaving the used
+      names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will
+      be treated as equal and both stored as `{"key": 1}`.
+    - Internally, name/value pairs are stored in lexicographical order of the
+      names. Objects will also be serialized (see @ref dump) in this order.
+      For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored
+      and serialized as `{"a": 2, "b": 1}`.
+    - When comparing objects, the order of the name/value pairs is irrelevant.
+      This makes objects interoperable in the sense that they will not be
+      affected by these differences. For instance, `{"b": 1, "a": 2}` and
+      `{"a": 2, "b": 1}` will be treated as equal.
 
-    @image html callback_events.png "Example when certain parse events are triggered"
+    #### Limits
 
-    @since version 1.0.0
-    */
-    enum class parse_event_t : uint8_t
-    {
-        /// the parser read `{` and started to process a JSON object
-        object_start,
-        /// the parser read `}` and finished processing a JSON object
-        object_end,
-        /// the parser read `[` and started to process a JSON array
-        array_start,
-        /// the parser read `]` and finished processing a JSON array
-        array_end,
-        /// the parser read a key of a value in an object
-        key,
-        /// the parser finished reading a JSON value
-        value
-    };
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the maximum depth of nesting.
+
+    In this class, the object's limit of nesting is not constraint explicitly.
+    However, a maximum depth of nesting may be introduced by the compiler or
+    runtime environment. A theoretical limit can be queried by calling the
+    @ref max_size function of a JSON object.
+
+    #### Storage
+
+    Objects are stored as pointers in a @ref basic_json type. That is, for any
+    access to object values, a pointer of type `object_t*` must be
+    dereferenced.
+
+    @sa @ref array_t -- type for an array value
+
+    @since version 1.0.0
+
+    @note The order name/value pairs are added to the object is *not*
+    preserved by the library. Therefore, iterating an object may return
+    name/value pairs in a different order than they were originally stored. In
+    fact, keys will be traversed in alphabetical order as `std::map` with
+    `std::less` is used by default. Please note this behavior conforms to [RFC
+    7159](http://rfc7159.net/rfc7159), because any order implements the
+    specified "unordered" nature of JSON objects.
+    */
+    using object_t = ObjectType<StringType,
+          basic_json,
+          std::less<StringType>,
+          AllocatorType<std::pair<const StringType,
+          basic_json>>>;
 
     /*!
-    @brief per-element parser callback type
+    @brief a type for an array
 
-    With a parser callback function, the result of parsing a JSON text can be
-    influenced. When passed to @ref parse(std::istream&, const
-    parser_callback_t) or @ref parse(const CharT, const parser_callback_t),
-    it is called on certain events (passed as @ref parse_event_t via parameter
-    @a event) with a set recursion depth @a depth and context JSON value
-    @a parsed. The return value of the callback function is a boolean
-    indicating whether the element that emitted the callback shall be kept or
-    not.
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
+    > An array is an ordered sequence of zero or more values.
 
-    We distinguish six scenarios (determined by the event type) in which the
-    callback function can be called. The following table describes the values
-    of the parameters @a depth, @a event, and @a parsed.
+    To store objects in C++, a type is defined by the template parameters
+    explained below.
 
-    parameter @a event | description | parameter @a depth | parameter @a parsed
-    ------------------ | ----------- | ------------------ | -------------------
-    parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded
-    parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key
-    parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object
-    parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded
-    parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
-    parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
+    @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
+    `std::list`)
+    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
 
-    @image html callback_events.png "Example when certain parse events are triggered"
+    #### Default type
 
-    Discarding a value (i.e., returning `false`) has different effects
-    depending on the context in which function was called:
+    With the default values for @a ArrayType (`std::vector`) and @a
+    AllocatorType (`std::allocator`), the default value for @a array_t is:
 
-    - Discarded values in structured types are skipped. That is, the parser
-      will behave as if the discarded value was never read.
-    - In case a value outside a structured type is skipped, it is replaced
-      with `null`. This case happens if the top-level element is skipped.
+    @code {.cpp}
+    std::vector<
+      basic_json, // value_type
+      std::allocator<basic_json> // allocator_type
+    >
+    @endcode
 
-    @param[in] depth  the depth of the recursion during parsing
+    #### Limits
 
-    @param[in] event  an event of type parse_event_t indicating the context in
-    the callback function has been called
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the maximum depth of nesting.
 
-    @param[in,out] parsed  the current intermediate parse result; note that
-    writing to this value has no effect for parse_event_t::key events
+    In this class, the array's limit of nesting is not constraint explicitly.
+    However, a maximum depth of nesting may be introduced by the compiler or
+    runtime environment. A theoretical limit can be queried by calling the
+    @ref max_size function of a JSON array.
 
-    @return Whether the JSON value which called the function during parsing
-    should be kept (`true`) or not (`false`). In the latter case, it is either
-    skipped completely or replaced by an empty discarded object.
+    #### Storage
 
-    @sa @ref parse(std::istream&, parser_callback_t) or
-    @ref parse(const CharT, const parser_callback_t) for examples
+    Arrays are stored as pointers in a @ref basic_json type. That is, for any
+    access to array values, a pointer of type `array_t*` must be dereferenced.
+
+    @sa @ref object_t -- type for an object value
 
     @since version 1.0.0
     */
-    using parser_callback_t = std::function<bool(int depth,
-                              parse_event_t event,
-                              basic_json& parsed)>;
+    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
 
+    /*!
+    @brief a type for a string
 
-    //////////////////
-    // constructors //
-    //////////////////
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
+    > A string is a sequence of zero or more Unicode characters.
 
-    /// @name constructors and destructors
-    /// Constructors of class @ref basic_json, copy/move constructor, copy
-    /// assignment, static functions creating objects, and the destructor.
-    /// @{
+    To store objects in C++, a type is defined by the template parameter
+    described below. Unicode values are split by the JSON class into
+    byte-sized characters during deserialization.
 
-    /*!
-    @brief create an empty value with a given type
+    @tparam StringType  the container to store strings (e.g., `std::string`).
+    Note this container is used for keys/names in objects, see @ref object_t.
 
-    Create an empty JSON value with a given type. The value will be default
-    initialized with an empty value which depends on the type:
+    #### Default type
 
-    Value type  | initial value
-    ----------- | -------------
-    null        | `null`
-    boolean     | `false`
-    string      | `""`
-    number      | `0`
-    object      | `{}`
-    array       | `[]`
+    With the default values for @a StringType (`std::string`), the default
+    value for @a string_t is:
 
-    @param[in] value_type  the type of the value to create
+    @code {.cpp}
+    std::string
+    @endcode
 
-    @complexity Constant.
+    #### Encoding
 
-    @throw std::bad_alloc if allocation for object, array, or string value
-    fails
+    Strings are stored in UTF-8 encoding. Therefore, functions like
+    `std::string::size()` or `std::string::length()` return the number of
+    bytes in the string rather than the number of characters or glyphs.
 
-    @liveexample{The following code shows the constructor for different @ref
-    value_t values,basic_json__value_t}
+    #### String comparison
+
+    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    > Software implementations are typically required to test names of object
+    > members for equality. Implementations that transform the textual
+    > representation into sequences of Unicode code units and then perform the
+    > comparison numerically, code unit by code unit, are interoperable in the
+    > sense that implementations will agree in all cases on equality or
+    > inequality of two strings. For example, implementations that compare
+    > strings with escaped characters unconverted may incorrectly find that
+    > `"a\\b"` and `"a\u005Cb"` are not equal.
+
+    This implementation is interoperable as it does compare strings code unit
+    by code unit.
+
+    #### Storage
 
-    @sa @ref basic_json(std::nullptr_t) -- create a `null` value
-    @sa @ref basic_json(boolean_t value) -- create a boolean value
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const object_t&) -- create a object value
-    @sa @ref basic_json(const array_t&) -- create a array value
-    @sa @ref basic_json(const number_float_t) -- create a number
-    (floating-point) value
-    @sa @ref basic_json(const number_integer_t) -- create a number (integer)
-    value
-    @sa @ref basic_json(const number_unsigned_t) -- create a number (unsigned)
-    value
+    String values are stored as pointers in a @ref basic_json type. That is,
+    for any access to string values, a pointer of type `string_t*` must be
+    dereferenced.
 
     @since version 1.0.0
     */
-    basic_json(const value_t value_type)
-        : m_type(value_type), m_value(value_type)
-    {
-        assert_invariant();
-    }
+    using string_t = StringType;
 
     /*!
-    @brief create a null object
+    @brief a type for a boolean
 
-    Create a `null` JSON value. It either takes a null pointer as parameter
-    (explicitly creating `null`) or no parameter (implicitly creating `null`).
-    The passed null pointer itself is not read -- it is only used to choose
-    the right constructor.
+    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
+    type which differentiates the two literals `true` and `false`.
 
-    @complexity Constant.
+    To store objects in C++, a type is defined by the template parameter @a
+    BooleanType which chooses the type to use.
 
-    @exceptionsafety No-throw guarantee: this constructor never throws
-    exceptions.
+    #### Default type
 
-    @liveexample{The following code shows the constructor with and without a
-    null pointer parameter.,basic_json__nullptr_t}
+    With the default values for @a BooleanType (`bool`), the default value for
+    @a boolean_t is:
+
+    @code {.cpp}
+    bool
+    @endcode
+
+    #### Storage
+
+    Boolean values are stored directly inside a @ref basic_json type.
 
     @since version 1.0.0
     */
-    basic_json(std::nullptr_t = nullptr) noexcept
-        : basic_json(value_t::null)
-    {
-        assert_invariant();
-    }
+    using boolean_t = BooleanType;
 
     /*!
-    @brief create an object (explicit)
+    @brief a type for a number (integer)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
+
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
 
-    Create an object JSON value with a given content.
+    To store integer numbers in C++, a type is defined by the template
+    parameter @a NumberIntegerType which chooses the type to use.
 
-    @param[in] val  a value for the object
+    #### Default type
 
-    @complexity Linear in the size of the passed @a val.
+    With the default values for @a NumberIntegerType (`int64_t`), the default
+    value for @a number_integer_t is:
 
-    @throw std::bad_alloc if allocation for object value fails
+    @code {.cpp}
+    int64_t
+    @endcode
 
-    @liveexample{The following code shows the constructor with an @ref
-    object_t parameter.,basic_json__object_t}
+    #### Default behavior
 
-    @sa @ref basic_json(const CompatibleObjectType&) -- create an object value
-    from a compatible STL container
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in integer literals lead to an interpretation as octal
+      number. Internally, the value will be stored as decimal number. For
+      instance, the C++ integer literal `010` will be serialized to `8`.
+      During deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
 
-    @since version 1.0.0
-    */
-    basic_json(const object_t& val)
-        : m_type(value_t::object), m_value(val)
-    {
-        assert_invariant();
-    }
+    #### Limits
 
-    /*!
-    @brief create an object (implicit)
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the range and precision of numbers.
 
-    Create an object JSON value with a given content. This constructor allows
-    any type @a CompatibleObjectType that can be used to construct values of
-    type @ref object_t.
+    When the default type is used, the maximal integer number that can be
+    stored is `9223372036854775807` (INT64_MAX) and the minimal integer number
+    that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers
+    that are out of range will yield over/underflow when used in a
+    constructor. During deserialization, too large or small integer numbers
+    will be automatically be stored as @ref number_unsigned_t or @ref
+    number_float_t.
 
-    @tparam CompatibleObjectType An object type whose `key_type` and
-    `value_type` is compatible to @ref object_t. Examples include `std::map`,
-    `std::unordered_map`, `std::multimap`, and `std::unordered_multimap` with
-    a `key_type` of `std::string`, and a `value_type` from which a @ref
-    basic_json value can be constructed.
+    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    > Note that when such software is used, numbers that are integers and are
+    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
+    > that implementations will agree exactly on their numeric values.
 
-    @param[in] val  a value for the object
+    As this range is a subrange of the exactly supported range [INT64_MIN,
+    INT64_MAX], this class's integer type is interoperable.
 
-    @complexity Linear in the size of the passed @a val.
+    #### Storage
 
-    @throw std::bad_alloc if allocation for object value fails
+    Integer number values are stored directly inside a @ref basic_json type.
 
-    @liveexample{The following code shows the constructor with several
-    compatible object type parameters.,basic_json__CompatibleObjectType}
+    @sa @ref number_float_t -- type for number values (floating-point)
 
-    @sa @ref basic_json(const object_t&) -- create an object value
+    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
 
     @since version 1.0.0
     */
-    template<class CompatibleObjectType, typename std::enable_if<
-                 std::is_constructible<typename object_t::key_type, typename CompatibleObjectType::key_type>::value and
-                 std::is_constructible<basic_json, typename CompatibleObjectType::mapped_type>::value, int>::type = 0>
-    basic_json(const CompatibleObjectType& val)
-        : m_type(value_t::object)
-    {
-        using std::begin;
-        using std::end;
-        m_value.object = create<object_t>(begin(val), end(val));
-        assert_invariant();
-    }
+    using number_integer_t = NumberIntegerType;
 
     /*!
-    @brief create an array (explicit)
+    @brief a type for a number (unsigned)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
 
-    Create an array JSON value with a given content.
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
 
-    @param[in] val  a value for the array
+    To store unsigned integer numbers in C++, a type is defined by the
+    template parameter @a NumberUnsignedType which chooses the type to use.
 
-    @complexity Linear in the size of the passed @a val.
+    #### Default type
 
-    @throw std::bad_alloc if allocation for array value fails
+    With the default values for @a NumberUnsignedType (`uint64_t`), the
+    default value for @a number_unsigned_t is:
 
-    @liveexample{The following code shows the constructor with an @ref array_t
-    parameter.,basic_json__array_t}
+    @code {.cpp}
+    uint64_t
+    @endcode
 
-    @sa @ref basic_json(const CompatibleArrayType&) -- create an array value
-    from a compatible STL containers
+    #### Default behavior
 
-    @since version 1.0.0
-    */
-    basic_json(const array_t& val)
-        : m_type(value_t::array), m_value(val)
-    {
-        assert_invariant();
-    }
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in integer literals lead to an interpretation as octal
+      number. Internally, the value will be stored as decimal number. For
+      instance, the C++ integer literal `010` will be serialized to `8`.
+      During deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
 
-    /*!
-    @brief create an array (implicit)
+    #### Limits
 
-    Create an array JSON value with a given content. This constructor allows
-    any type @a CompatibleArrayType that can be used to construct values of
-    type @ref array_t.
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the range and precision of numbers.
 
-    @tparam CompatibleArrayType An object type whose `value_type` is
-    compatible to @ref array_t. Examples include `std::vector`, `std::deque`,
-    `std::list`, `std::forward_list`, `std::array`, `std::set`,
-    `std::unordered_set`, `std::multiset`, and `unordered_multiset` with a
-    `value_type` from which a @ref basic_json value can be constructed.
+    When the default type is used, the maximal integer number that can be
+    stored is `18446744073709551615` (UINT64_MAX) and the minimal integer
+    number that can be stored is `0`. Integer numbers that are out of range
+    will yield over/underflow when used in a constructor. During
+    deserialization, too large or small integer numbers will be automatically
+    be stored as @ref number_integer_t or @ref number_float_t.
 
-    @param[in] val  a value for the array
+    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    > Note that when such software is used, numbers that are integers and are
+    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
+    > that implementations will agree exactly on their numeric values.
 
-    @complexity Linear in the size of the passed @a val.
+    As this range is a subrange (when considered in conjunction with the
+    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
+    this class's integer type is interoperable.
 
-    @throw std::bad_alloc if allocation for array value fails
+    #### Storage
 
-    @liveexample{The following code shows the constructor with several
-    compatible array type parameters.,basic_json__CompatibleArrayType}
+    Integer number values are stored directly inside a @ref basic_json type.
 
-    @sa @ref basic_json(const array_t&) -- create an array value
+    @sa @ref number_float_t -- type for number values (floating-point)
+    @sa @ref number_integer_t -- type for number values (integer)
 
-    @since version 1.0.0
+    @since version 2.0.0
     */
-    template<class CompatibleArrayType, typename std::enable_if<
-                 not std::is_same<CompatibleArrayType, typename basic_json_t::iterator>::value and
-                 not std::is_same<CompatibleArrayType, typename basic_json_t::const_iterator>::value and
-                 not std::is_same<CompatibleArrayType, typename basic_json_t::reverse_iterator>::value and
-                 not std::is_same<CompatibleArrayType, typename basic_json_t::const_reverse_iterator>::value and
-                 not std::is_same<CompatibleArrayType, typename array_t::iterator>::value and
-                 not std::is_same<CompatibleArrayType, typename array_t::const_iterator>::value and
-                 std::is_constructible<basic_json, typename CompatibleArrayType::value_type>::value, int>::type = 0>
-    basic_json(const CompatibleArrayType& val)
-        : m_type(value_t::array)
-    {
-        using std::begin;
-        using std::end;
-        m_value.array = create<array_t>(begin(val), end(val));
-        assert_invariant();
-    }
+    using number_unsigned_t = NumberUnsignedType;
 
     /*!
-    @brief create a string (explicit)
+    @brief a type for a number (floating-point)
+
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
 
-    Create an string JSON value with a given content.
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
 
-    @param[in] val  a value for the string
+    To store floating-point numbers in C++, a type is defined by the template
+    parameter @a NumberFloatType which chooses the type to use.
 
-    @complexity Linear in the size of the passed @a val.
+    #### Default type
 
-    @throw std::bad_alloc if allocation for string value fails
+    With the default values for @a NumberFloatType (`double`), the default
+    value for @a number_float_t is:
 
-    @liveexample{The following code shows the constructor with an @ref
-    string_t parameter.,basic_json__string_t}
+    @code {.cpp}
+    double
+    @endcode
 
-    @sa @ref basic_json(const typename string_t::value_type*) -- create a
-    string value from a character pointer
-    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
-    from a compatible string container
+    #### Default behavior
 
-    @since version 1.0.0
-    */
-    basic_json(const string_t& val)
-        : m_type(value_t::string), m_value(val)
-    {
-        assert_invariant();
-    }
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in floating-point literals will be ignored. Internally,
+      the value will be stored as decimal number. For instance, the C++
+      floating-point literal `01.2` will be serialized to `1.2`. During
+      deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
 
-    /*!
-    @brief create a string (explicit)
+    #### Limits
 
-    Create a string JSON value with a given content.
+    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    > This specification allows implementations to set limits on the range and
+    > precision of numbers accepted. Since software that implements IEEE
+    > 754-2008 binary64 (double precision) numbers is generally available and
+    > widely used, good interoperability can be achieved by implementations
+    > that expect no more precision or range than these provide, in the sense
+    > that implementations will approximate JSON numbers within the expected
+    > precision.
 
-    @param[in] val  a literal value for the string
+    This implementation does exactly follow this approach, as it uses double
+    precision floating-point numbers. Note values smaller than
+    `-1.79769313486232e+308` and values greater than `1.79769313486232e+308`
+    will be stored as NaN internally and be serialized to `null`.
 
-    @complexity Linear in the size of the passed @a val.
+    #### Storage
 
-    @throw std::bad_alloc if allocation for string value fails
+    Floating-point number values are stored directly inside a @ref basic_json
+    type.
 
-    @liveexample{The following code shows the constructor with string literal
-    parameter.,basic_json__string_t_value_type}
+    @sa @ref number_integer_t -- type for number values (integer)
 
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const CompatibleStringType&) -- create a string value
-    from a compatible string container
+    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
 
     @since version 1.0.0
     */
-    basic_json(const typename string_t::value_type* val)
-        : basic_json(string_t(val))
-    {
-        assert_invariant();
-    }
+    using number_float_t = NumberFloatType;
 
-    /*!
-    @brief create a string (implicit)
+    /// @}
 
-    Create a string JSON value with a given content.
+  private:
 
-    @param[in] val  a value for the string
+    /// helper for exception-safe object creation
+    template<typename T, typename... Args>
+    static T* create(Args&& ... args)
+    {
+        AllocatorType<T> alloc;
+        auto deleter = [&](T * object)
+        {
+            alloc.deallocate(object, 1);
+        };
+        std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
+        alloc.construct(object.get(), std::forward<Args>(args)...);
+        assert(object != nullptr);
+        return object.release();
+    }
 
-    @tparam CompatibleStringType an string type which is compatible to @ref
-    string_t, for instance `std::string`.
+    ////////////////////////
+    // JSON value storage //
+    ////////////////////////
 
-    @complexity Linear in the size of the passed @a val.
+    /*!
+    @brief a JSON value
 
-    @throw std::bad_alloc if allocation for string value fails
+    The actual storage for a JSON value of the @ref basic_json class. This
+    union combines the different storage types for the JSON value types
+    defined in @ref value_t.
 
-    @liveexample{The following code shows the construction of a string value
-    from a compatible type.,basic_json__CompatibleStringType}
+    JSON type | value_t type    | used type
+    --------- | --------------- | ------------------------
+    object    | object          | pointer to @ref object_t
+    array     | array           | pointer to @ref array_t
+    string    | string          | pointer to @ref string_t
+    boolean   | boolean         | @ref boolean_t
+    number    | number_integer  | @ref number_integer_t
+    number    | number_unsigned | @ref number_unsigned_t
+    number    | number_float    | @ref number_float_t
+    null      | null            | *no value is stored*
 
-    @sa @ref basic_json(const string_t&) -- create a string value
-    @sa @ref basic_json(const typename string_t::value_type*) -- create a
-    string value from a character pointer
+    @note Variable-length types (objects, arrays, and strings) are stored as
+    pointers. The size of the union should not exceed 64 bits if the default
+    value types are used.
 
     @since version 1.0.0
     */
-    template<class CompatibleStringType, typename std::enable_if<
-                 std::is_constructible<string_t, CompatibleStringType>::value, int>::type = 0>
-    basic_json(const CompatibleStringType& val)
-        : basic_json(string_t(val))
+    union json_value
     {
-        assert_invariant();
-    }
+        /// object (stored with pointer to save storage)
+        object_t* object;
+        /// array (stored with pointer to save storage)
+        array_t* array;
+        /// string (stored with pointer to save storage)
+        string_t* string;
+        /// boolean
+        boolean_t boolean;
+        /// number (integer)
+        number_integer_t number_integer;
+        /// number (unsigned integer)
+        number_unsigned_t number_unsigned;
+        /// number (floating-point)
+        number_float_t number_float;
 
-    /*!
-    @brief create a boolean (explicit)
+        /// default constructor (for null values)
+        json_value() = default;
+        /// constructor for booleans
+        json_value(boolean_t v) noexcept : boolean(v) {}
+        /// constructor for numbers (integer)
+        json_value(number_integer_t v) noexcept : number_integer(v) {}
+        /// constructor for numbers (unsigned)
+        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
+        /// constructor for numbers (floating-point)
+        json_value(number_float_t v) noexcept : number_float(v) {}
+        /// constructor for empty values of a given type
+        json_value(value_t t)
+        {
+            switch (t)
+            {
+                case value_t::object:
+                {
+                    object = create<object_t>();
+                    break;
+                }
 
-    Creates a JSON boolean type from a given value.
+                case value_t::array:
+                {
+                    array = create<array_t>();
+                    break;
+                }
 
-    @param[in] val  a boolean value to store
+                case value_t::string:
+                {
+                    string = create<string_t>("");
+                    break;
+                }
 
-    @complexity Constant.
+                case value_t::boolean:
+                {
+                    boolean = boolean_t(false);
+                    break;
+                }
 
-    @liveexample{The example below demonstrates boolean
-    values.,basic_json__boolean_t}
+                case value_t::number_integer:
+                {
+                    number_integer = number_integer_t(0);
+                    break;
+                }
 
-    @since version 1.0.0
-    */
-    basic_json(boolean_t val) noexcept
-        : m_type(value_t::boolean), m_value(val)
-    {
-        assert_invariant();
-    }
+                case value_t::number_unsigned:
+                {
+                    number_unsigned = number_unsigned_t(0);
+                    break;
+                }
 
-    /*!
-    @brief create an integer number (explicit)
+                case value_t::number_float:
+                {
+                    number_float = number_float_t(0.0);
+                    break;
+                }
 
-    Create an integer number JSON value with a given content.
+                case value_t::null:
+                {
+                    break;
+                }
 
-    @tparam T A helper type to remove this function via SFINAE in case @ref
-    number_integer_t is the same as `int`. In this case, this constructor
-    would have the same signature as @ref basic_json(const int value). Note
-    the helper type @a T is not visible in this constructor's interface.
+                default:
+                {
+                    if (t == value_t::null)
+                    {
+                        JSON_THROW(other_error::create(500, "961c151d2e87f2686a955a9be24d316f1362bf21 2.1.1")); // LCOV_EXCL_LINE
+                    }
+                    break;
+                }
+            }
+        }
 
-    @param[in] val  an integer to create a JSON number from
+        /// constructor for strings
+        json_value(const string_t& value)
+        {
+            string = create<string_t>(value);
+        }
 
-    @complexity Constant.
+        /// constructor for objects
+        json_value(const object_t& value)
+        {
+            object = create<object_t>(value);
+        }
 
-    @liveexample{The example below shows the construction of an integer
-    number value.,basic_json__number_integer_t}
+        /// constructor for arrays
+        json_value(const array_t& value)
+        {
+            array = create<array_t>(value);
+        }
+    };
 
-    @sa @ref basic_json(const int) -- create a number value (integer)
-    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
-    value (integer) from a compatible number type
+    /*!
+    @brief checks the class invariants
 
-    @since version 1.0.0
+    This function asserts the class invariants. It needs to be called at the
+    end of every constructor to make sure that created objects respect the
+    invariant. Furthermore, it has to be called each time the type of a JSON
+    value is changed, because the invariant expresses a relationship between
+    @a m_type and @a m_value.
     */
-    template<typename T, typename std::enable_if<
-                 not (std::is_same<T, int>::value) and
-                 std::is_same<T, number_integer_t>::value, int>::type = 0>
-    basic_json(const number_integer_t val) noexcept
-        : m_type(value_t::number_integer), m_value(val)
+    void assert_invariant() const
     {
-        assert_invariant();
+        assert(m_type != value_t::object or m_value.object != nullptr);
+        assert(m_type != value_t::array or m_value.array != nullptr);
+        assert(m_type != value_t::string or m_value.string != nullptr);
     }
 
-    /*!
-    @brief create an integer number from an enum type (explicit)
-
-    Create an integer number JSON value with a given content.
-
-    @param[in] val  an integer to create a JSON number from
-
-    @note This constructor allows to pass enums directly to a constructor. As
-    C++ has no way of specifying the type of an anonymous enum explicitly, we
-    can only rely on the fact that such values implicitly convert to int. As
-    int may already be the same type of number_integer_t, we may need to
-    switch off the constructor @ref basic_json(const number_integer_t).
+  public:
+    //////////////////////////
+    // JSON parser callback //
+    //////////////////////////
 
-    @complexity Constant.
+    /*!
+    @brief JSON callback events
 
-    @liveexample{The example below shows the construction of an integer
-    number value from an anonymous enum.,basic_json__const_int}
+    This enumeration lists the parser events that can trigger calling a
+    callback function of type @ref parser_callback_t during parsing.
 
-    @sa @ref basic_json(const number_integer_t) -- create a number value
-    (integer)
-    @sa @ref basic_json(const CompatibleNumberIntegerType) -- create a number
-    value (integer) from a compatible number type
+    @image html callback_events.png "Example when certain parse events are triggered"
 
     @since version 1.0.0
     */
-    basic_json(const int val) noexcept
-        : m_type(value_t::number_integer),
-          m_value(static_cast<number_integer_t>(val))
+    enum class parse_event_t : uint8_t
     {
-        assert_invariant();
-    }
+        /// the parser read `{` and started to process a JSON object
+        object_start,
+        /// the parser read `}` and finished processing a JSON object
+        object_end,
+        /// the parser read `[` and started to process a JSON array
+        array_start,
+        /// the parser read `]` and finished processing a JSON array
+        array_end,
+        /// the parser read a key of a value in an object
+        key,
+        /// the parser finished reading a JSON value
+        value
+    };
 
     /*!
-    @brief create an integer number (implicit)
+    @brief per-element parser callback type
 
-    Create an integer number JSON value with a given content. This constructor
-    allows any type @a CompatibleNumberIntegerType that can be used to
-    construct values of type @ref number_integer_t.
+    With a parser callback function, the result of parsing a JSON text can be
+    influenced. When passed to @ref parse(std::istream&, const
+    parser_callback_t) or @ref parse(const CharT, const parser_callback_t),
+    it is called on certain events (passed as @ref parse_event_t via parameter
+    @a event) with a set recursion depth @a depth and context JSON value
+    @a parsed. The return value of the callback function is a boolean
+    indicating whether the element that emitted the callback shall be kept or
+    not.
 
-    @tparam CompatibleNumberIntegerType An integer type which is compatible to
-    @ref number_integer_t. Examples include the types `int`, `int32_t`,
-    `long`, and `short`.
+    We distinguish six scenarios (determined by the event type) in which the
+    callback function can be called. The following table describes the values
+    of the parameters @a depth, @a event, and @a parsed.
 
-    @param[in] val  an integer to create a JSON number from
+    parameter @a event | description | parameter @a depth | parameter @a parsed
+    ------------------ | ----------- | ------------------ | -------------------
+    parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded
+    parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key
+    parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object
+    parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded
+    parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
+    parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
 
-    @complexity Constant.
+    @image html callback_events.png "Example when certain parse events are triggered"
 
-    @liveexample{The example below shows the construction of several integer
-    number values from compatible
-    types.,basic_json__CompatibleIntegerNumberType}
+    Discarding a value (i.e., returning `false`) has different effects
+    depending on the context in which function was called:
 
-    @sa @ref basic_json(const number_integer_t) -- create a number value
-    (integer)
-    @sa @ref basic_json(const int) -- create a number value (integer)
+    - Discarded values in structured types are skipped. That is, the parser
+      will behave as if the discarded value was never read.
+    - In case a value outside a structured type is skipped, it is replaced
+      with `null`. This case happens if the top-level element is skipped.
 
-    @since version 1.0.0
-    */
-    template<typename CompatibleNumberIntegerType, typename std::enable_if<
-                 std::is_constructible<number_integer_t, CompatibleNumberIntegerType>::value and
-                 std::numeric_limits<CompatibleNumberIntegerType>::is_integer and
-                 std::numeric_limits<CompatibleNumberIntegerType>::is_signed,
-                 CompatibleNumberIntegerType>::type = 0>
-    basic_json(const CompatibleNumberIntegerType val) noexcept
-        : m_type(value_t::number_integer),
-          m_value(static_cast<number_integer_t>(val))
-    {
-        assert_invariant();
-    }
+    @param[in] depth  the depth of the recursion during parsing
 
-    /*!
-    @brief create an unsigned integer number (explicit)
+    @param[in] event  an event of type parse_event_t indicating the context in
+    the callback function has been called
 
-    Create an unsigned integer number JSON value with a given content.
+    @param[in,out] parsed  the current intermediate parse result; note that
+    writing to this value has no effect for parse_event_t::key events
 
-    @tparam T  helper type to compare number_unsigned_t and unsigned int (not
-    visible in) the interface.
+    @return Whether the JSON value which called the function during parsing
+    should be kept (`true`) or not (`false`). In the latter case, it is either
+    skipped completely or replaced by an empty discarded object.
 
-    @param[in] val  an integer to create a JSON number from
+    @sa @ref parse(std::istream&, parser_callback_t) or
+    @ref parse(const CharT, const parser_callback_t) for examples
 
-    @complexity Constant.
+    @since version 1.0.0
+    */
+    using parser_callback_t = std::function<bool(int depth,
+                              parse_event_t event,
+                              basic_json& parsed)>;
 
-    @sa @ref basic_json(const CompatibleNumberUnsignedType) -- create a number
-    value (unsigned integer) from a compatible number type
 
-    @since version 2.0.0
-    */
-    template<typename T, typename std::enable_if<
-                 not (std::is_same<T, int>::value) and
-                 std::is_same<T, number_unsigned_t>::value, int>::type = 0>
-    basic_json(const number_unsigned_t val) noexcept
-        : m_type(value_t::number_unsigned), m_value(val)
-    {
-        assert_invariant();
-    }
+    //////////////////
+    // constructors //
+    //////////////////
+
+    /// @name constructors and destructors
+    /// Constructors of class @ref basic_json, copy/move constructor, copy
+    /// assignment, static functions creating objects, and the destructor.
+    /// @{
 
     /*!
-    @brief create an unsigned number (implicit)
+    @brief create an empty value with a given type
 
-    Create an unsigned number JSON value with a given content. This
-    constructor allows any type @a CompatibleNumberUnsignedType that can be
-    used to construct values of type @ref number_unsigned_t.
+    Create an empty JSON value with a given type. The value will be default
+    initialized with an empty value which depends on the type:
 
-    @tparam CompatibleNumberUnsignedType An integer type which is compatible
-    to @ref number_unsigned_t. Examples may include the types `unsigned int`,
-    `uint32_t`, or `unsigned short`.
+    Value type  | initial value
+    ----------- | -------------
+    null        | `null`
+    boolean     | `false`
+    string      | `""`
+    number      | `0`
+    object      | `{}`
+    array       | `[]`
 
-    @param[in] val  an unsigned integer to create a JSON number from
+    @param[in] value_type  the type of the value to create
 
     @complexity Constant.
 
-    @sa @ref basic_json(const number_unsigned_t) -- create a number value
-    (unsigned)
+    @liveexample{The following code shows the constructor for different @ref
+    value_t values,basic_json__value_t}
 
-    @since version 2.0.0
+    @since version 1.0.0
     */
-    template<typename CompatibleNumberUnsignedType, typename std::enable_if <
-                 std::is_constructible<number_unsigned_t, CompatibleNumberUnsignedType>::value and
-                 std::numeric_limits<CompatibleNumberUnsignedType>::is_integer and
-                 not std::numeric_limits<CompatibleNumberUnsignedType>::is_signed,
-                 CompatibleNumberUnsignedType>::type = 0>
-    basic_json(const CompatibleNumberUnsignedType val) noexcept
-        : m_type(value_t::number_unsigned),
-          m_value(static_cast<number_unsigned_t>(val))
+    basic_json(const value_t value_type)
+        : m_type(value_type), m_value(value_type)
     {
         assert_invariant();
     }
 
     /*!
-    @brief create a floating-point number (explicit)
-
-    Create a floating-point number JSON value with a given content.
-
-    @param[in] val  a floating-point value to create a JSON number from
+    @brief create a null object
 
-    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
-    disallows NaN values:
-    > Numeric values that cannot be represented in the grammar below (such as
-    > Infinity and NaN) are not permitted.
-    In case the parameter @a val is not a number, a JSON null value is created
-    instead.
+    Create a `null` JSON value. It either takes a null pointer as parameter
+    (explicitly creating `null`) or no parameter (implicitly creating `null`).
+    The passed null pointer itself is not read -- it is only used to choose
+    the right constructor.
 
     @complexity Constant.
 
-    @liveexample{The following example creates several floating-point
-    values.,basic_json__number_float_t}
+    @exceptionsafety No-throw guarantee: this constructor never throws
+    exceptions.
 
-    @sa @ref basic_json(const CompatibleNumberFloatType) -- create a number
-    value (floating-point) from a compatible number type
+    @liveexample{The following code shows the constructor with and without a
+    null pointer parameter.,basic_json__nullptr_t}
 
     @since version 1.0.0
     */
-    basic_json(const number_float_t val) noexcept
-        : m_type(value_t::number_float), m_value(val)
+    basic_json(std::nullptr_t = nullptr) noexcept
+        : basic_json(value_t::null)
     {
-        // replace infinity and NAN by null
-        if (not std::isfinite(val))
-        {
-            m_type = value_t::null;
-            m_value = json_value();
-        }
-
         assert_invariant();
     }
 
     /*!
-    @brief create an floating-point number (implicit)
+    @brief create a JSON value
 
-    Create an floating-point number JSON value with a given content. This
-    constructor allows any type @a CompatibleNumberFloatType that can be used
-    to construct values of type @ref number_float_t.
+    This is a "catch all" constructor for all compatible JSON types; that is,
+    types for which a `to_json()` method exsits. The constructor forwards the
+    parameter @a val to that method (to `json_serializer<U>::to_json` method
+    with `U = uncvref_t<CompatibleType>`, to be exact).
 
-    @tparam CompatibleNumberFloatType A floating-point type which is
-    compatible to @ref number_float_t. Examples may include the types `float`
-    or `double`.
+    Template type @a CompatibleType includes, but is not limited to, the
+    following types:
+    - **arrays**: @ref array_t and all kinds of compatible containers such as
+      `std::vector`, `std::deque`, `std::list`, `std::forward_list`,
+      `std::array`, `std::set`, `std::unordered_set`, `std::multiset`, and
+      `unordered_multiset` with a `value_type` from which a @ref basic_json
+      value can be constructed.
+    - **objects**: @ref object_t and all kinds of compatible associative
+      containers such as `std::map`, `std::unordered_map`, `std::multimap`,
+      and `std::unordered_multimap` with a `key_type` compatible to
+      @ref string_t and a `value_type` from which a @ref basic_json value can
+      be constructed.
+    - **strings**: @ref string_t, string literals, and all compatible string
+      containers can be used.
+    - **numbers**: @ref number_integer_t, @ref number_unsigned_t,
+      @ref number_float_t, and all convertible number types such as `int`,
+      `size_t`, `int64_t`, `float` or `double` can be used.
+    - **boolean**: @ref boolean_t / `bool` can be used.
 
-    @param[in] val  a floating-point to create a JSON number from
+    See the examples below.
 
-    @note [RFC 7159](http://www.rfc-editor.org/rfc/rfc7159.txt), section 6
-    disallows NaN values:
-    > Numeric values that cannot be represented in the grammar below (such as
-    > Infinity and NaN) are not permitted.
-    In case the parameter @a val is not a number, a JSON null value is
-    created instead.
+    @tparam CompatibleType a type such that:
+    - @a CompatibleType is not derived from `std::istream`,
+    - @a CompatibleType is not @ref basic_json (to avoid hijacking copy/move
+         constructors),
+    - @a CompatibleType is not a @ref basic_json nested type (e.g.,
+         @ref json_pointer, @ref iterator, etc ...)
+    - @ref @ref json_serializer<U> has a
+         `to_json(basic_json_t&, CompatibleType&&)` method
 
-    @complexity Constant.
+    @tparam U = `uncvref_t<CompatibleType>`
 
-    @liveexample{The example below shows the construction of several
-    floating-point number values from compatible
-    types.,basic_json__CompatibleNumberFloatType}
+    @param[in] val the value to be forwarded
 
-    @sa @ref basic_json(const number_float_t) -- create a number value
-    (floating-point)
+    @complexity Usually linear in the size of the passed @a val, also
+                depending on the implementation of the called `to_json()`
+                method.
 
-    @since version 1.0.0
+    @throw what `json_serializer<U>::to_json()` throws
+
+    @liveexample{The following code shows the constructor with several
+    compatible types.,basic_json__CompatibleType}
+
+    @since version 2.1.0
     */
-    template<typename CompatibleNumberFloatType, typename = typename std::enable_if<
-                 std::is_constructible<number_float_t, CompatibleNumberFloatType>::value and
-                 std::is_floating_point<CompatibleNumberFloatType>::value>::type>
-    basic_json(const CompatibleNumberFloatType val) noexcept
-        : basic_json(number_float_t(val))
+    template<typename CompatibleType, typename U = detail::uncvref_t<CompatibleType>,
+             detail::enable_if_t<not std::is_base_of<std::istream, U>::value and
+                                 not std::is_same<U, basic_json_t>::value and
+                                 not detail::is_basic_json_nested_type<
+                                     basic_json_t, U>::value and
+                                 detail::has_to_json<basic_json, U>::value,
+                                 int> = 0>
+    basic_json(CompatibleType && val) noexcept(noexcept(JSONSerializer<U>::to_json(
+                std::declval<basic_json_t&>(), std::forward<CompatibleType>(val))))
     {
+        JSONSerializer<U>::to_json(*this, std::forward<CompatibleType>(val));
         assert_invariant();
     }
 
@@ -1613,10 +2330,12 @@ class basic_json
     value_t::array and @ref value_t::object are valid); when @a type_deduction
     is set to `true`, this parameter has no effect
 
-    @throw std::domain_error if @a type_deduction is `false`, @a manual_type
-    is `value_t::object`, but @a init contains an element which is not a pair
-    whose first element is a string; example: `"cannot create object from
-    initializer list"`
+    @throw type_error.301 if @a type_deduction is `false`, @a manual_type is
+    `value_t::object`, but @a init contains an element which is not a pair
+    whose first element is a string. In this case, the constructor could not
+    create an object. If @a type_deduction would have be `true`, an array
+    would have been created. See @ref object(std::initializer_list<basic_json>)
+    for an example.
 
     @complexity Linear in the size of the initializer list @a init.
 
@@ -1654,7 +2373,7 @@ class basic_json
             // if object is wanted but impossible, throw an exception
             if (manual_type == value_t::object and not is_an_object)
             {
-                throw std::domain_error("cannot create object from initializer list");
+                JSON_THROW(type_error::create(301, "cannot create object from initializer list"));
             }
         }
 
@@ -1730,16 +2449,17 @@ class basic_json
     related function @ref array(std::initializer_list<basic_json>), there are
     no cases which can only be expressed by this function. That is, any
     initializer list @a init can also be passed to the initializer list
-    constructor @ref basic_json(std::initializer_list<basic_json>, bool,
-    value_t).
+    constructor @ref basic_json(std::initializer_list<basic_json>, bool, value_t).
 
     @param[in] init  initializer list to create an object from (optional)
 
     @return JSON object value
 
-    @throw std::domain_error if @a init is not a pair whose first elements are
-    strings; thrown by
-    @ref basic_json(std::initializer_list<basic_json>, bool, value_t)
+    @throw type_error.301 if @a init is not a list of pairs whose first
+    elements are strings. In this case, no object can be created. When such a
+    value is passed to @ref basic_json(std::initializer_list<basic_json>, bool, value_t),
+    an array would have been created from the passed initializer list @a init.
+    See example below.
 
     @complexity Linear in the size of @a init.
 
@@ -1791,10 +2511,10 @@ class basic_json
     The semantics depends on the different types a JSON value can have:
     - In case of primitive types (number, boolean, or string), @a first must
       be `begin()` and @a last must be `end()`. In this case, the value is
-      copied. Otherwise, std::out_of_range is thrown.
+      copied. Otherwise, invalid_iterator.204 is thrown.
     - In case of structured types (array, object), the constructor behaves as
       similar versions for `std::vector`.
-    - In case of a null type, std::domain_error is thrown.
+    - In case of a null type, invalid_iterator.206 is thrown.
 
     @tparam InputIT an input iterator type (@ref iterator or @ref
     const_iterator)
@@ -1805,14 +2525,19 @@ class basic_json
     @pre Iterators @a first and @a last must be initialized. **This
          precondition is enforced with an assertion.**
 
-    @throw std::domain_error if iterators are not compatible; that is, do not
-    belong to the same JSON value; example: `"iterators are not compatible"`
-    @throw std::out_of_range if iterators are for a primitive type (number,
-    boolean, or string) where an out of range error can be detected easily;
-    example: `"iterators out of range"`
-    @throw std::bad_alloc if allocation for object, array, or string fails
-    @throw std::domain_error if called with a null value; example: `"cannot
-    use construct with iterators from null"`
+    @pre Range `[first, last)` is valid. Usually, this precondition cannot be
+         checked efficiently. Only certain edge cases are detected; see the
+         description of the exceptions below.
+
+    @throw invalid_iterator.201 if iterators @a first and @a last are not
+    compatible (i.e., do not belong to the same JSON value). In this case,
+    the range `[first, last)` is undefined.
+    @throw invalid_iterator.204 if iterators @a first and @a last belong to a
+    primitive type (number, boolean, or string), but @a first does not point
+    to the first element any more. In this case, the range `[first, last)` is
+    undefined. See example code below.
+    @throw invalid_iterator.206 if iterators @a first and @a last belong to a
+    null value. In this case, the range `[first, last)` is undefined.
 
     @complexity Linear in distance between @a first and @a last.
 
@@ -1832,7 +2557,7 @@ class basic_json
         // make sure iterator fits the current value
         if (first.m_object != last.m_object)
         {
-            throw std::domain_error("iterators are not compatible");
+            JSON_THROW(invalid_iterator::create(201, "iterators are not compatible"));
         }
 
         // copy type from first iterator
@@ -1849,7 +2574,7 @@ class basic_json
             {
                 if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
                 {
-                    throw std::out_of_range("iterators out of range");
+                    JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
                 }
                 break;
             }
@@ -1894,59 +2619,28 @@ class basic_json
 
             case value_t::object:
             {
-                m_value.object = create<object_t>(first.m_it.object_iterator, last.m_it.object_iterator);
+                m_value.object = create<object_t>(first.m_it.object_iterator,
+                                                  last.m_it.object_iterator);
                 break;
             }
 
             case value_t::array:
             {
-                m_value.array = create<array_t>(first.m_it.array_iterator, last.m_it.array_iterator);
+                m_value.array = create<array_t>(first.m_it.array_iterator,
+                                                last.m_it.array_iterator);
                 break;
             }
 
             default:
             {
-                throw std::domain_error("cannot use construct with iterators from " + first.m_object->type_name());
+                JSON_THROW(invalid_iterator::create(206, "cannot construct with iterators from " +
+                                                    first.m_object->type_name()));
             }
         }
 
         assert_invariant();
     }
 
-    /*!
-    @brief construct a JSON value given an input stream
-
-    @param[in,out] i  stream to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @deprecated This constructor is deprecated and will be removed in version
-      3.0.0 to unify the interface of the library. Deserialization will be
-      done by stream operators or by calling one of the `parse` functions,
-      e.g. @ref parse(std::istream&, const parser_callback_t). That is, calls
-      like `json j(i);` for an input stream @a i need to be replaced by
-      `json j = json::parse(i);`. See the example below.
-
-    @liveexample{The example below demonstrates constructing a JSON value from
-    a `std::stringstream` with and without callback
-    function.,basic_json__istream}
-
-    @since version 2.0.0, deprecated in version 2.0.3, to be removed in
-           version 3.0.0
-    */
-    JSON_DEPRECATED
-    explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)
-    {
-        *this = parser(i, cb).parse();
-        assert_invariant();
-    }
 
     ///////////////////////////////////////
     // other constructors and destructor //
@@ -1967,8 +2661,6 @@ class basic_json
     - The complexity is linear.
     - As postcondition, it holds: `other == basic_json(other)`.
 
-    @throw std::bad_alloc if allocation for object, array, or string fails.
-
     @liveexample{The following code shows an example for the copy
     constructor.,basic_json__basic_json}
 
@@ -2196,22 +2888,15 @@ class basic_json
     string_t dump(const int indent = -1) const
     {
         std::stringstream ss;
-        // fix locale problems
-        ss.imbue(std::locale::classic());
-
-        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
-        // string->float->string, string->double->string or string->long
-        // double->string; to be safe, we read this value from
-        // std::numeric_limits<number_float_t>::digits10
-        ss.precision(std::numeric_limits<double>::digits10);
+        serializer s(ss);
 
         if (indent >= 0)
         {
-            dump(ss, true, static_cast<unsigned int>(indent));
+            s.dump(*this, true, static_cast<unsigned int>(indent));
         }
         else
         {
-            dump(ss, false, 0);
+            s.dump(*this, false, 0);
         }
 
         return ss.str();
@@ -2577,246 +3262,99 @@ class basic_json
   private:
     //////////////////
     // value access //
-    //////////////////
-
-    /// get an object (explicit)
-    template<class T, typename std::enable_if<
-                 std::is_convertible<typename object_t::key_type, typename T::key_type>::value and
-                 std::is_convertible<basic_json_t, typename T::mapped_type>::value, int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_object())
-        {
-            return T(m_value.object->begin(), m_value.object->end());
-        }
-        else
-        {
-            throw std::domain_error("type must be object, but is " + type_name());
-        }
-    }
-
-    /// get an object (explicit)
-    object_t get_impl(object_t*) const
-    {
-        if (is_object())
-        {
-            return *(m_value.object);
-        }
-        else
-        {
-            throw std::domain_error("type must be object, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template<class T, typename std::enable_if<
-                 std::is_convertible<basic_json_t, typename T::value_type>::value and
-                 not std::is_same<basic_json_t, typename T::value_type>::value and
-                 not std::is_arithmetic<T>::value and
-                 not std::is_convertible<std::string, T>::value and
-                 not has_mapped_type<T>::value, int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_array())
-        {
-            T to_vector;
-            std::transform(m_value.array->begin(), m_value.array->end(),
-                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
-            {
-                return i.get<typename T::value_type>();
-            });
-            return to_vector;
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template<class T, typename std::enable_if<
-                 std::is_convertible<basic_json_t, T>::value and
-                 not std::is_same<basic_json_t, T>::value, int>::type = 0>
-    std::vector<T> get_impl(std::vector<T>*) const
-    {
-        if (is_array())
-        {
-            std::vector<T> to_vector;
-            to_vector.reserve(m_value.array->size());
-            std::transform(m_value.array->begin(), m_value.array->end(),
-                           std::inserter(to_vector, to_vector.end()), [](basic_json i)
-            {
-                return i.get<T>();
-            });
-            return to_vector;
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    template<class T, typename std::enable_if<
-                 std::is_same<basic_json, typename T::value_type>::value and
-                 not has_mapped_type<T>::value, int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_array())
-        {
-            return T(m_value.array->begin(), m_value.array->end());
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get an array (explicit)
-    array_t get_impl(array_t*) const
-    {
-        if (is_array())
-        {
-            return *(m_value.array);
-        }
-        else
-        {
-            throw std::domain_error("type must be array, but is " + type_name());
-        }
-    }
-
-    /// get a string (explicit)
-    template<typename T, typename std::enable_if<
-                 std::is_convertible<string_t, T>::value, int>::type = 0>
-    T get_impl(T*) const
-    {
-        if (is_string())
-        {
-            return *m_value.string;
-        }
-        else
-        {
-            throw std::domain_error("type must be string, but is " + type_name());
-        }
-    }
-
-    /// get a number (explicit)
-    template<typename T, typename std::enable_if<
-                 std::is_arithmetic<T>::value, int>::type = 0>
-    T get_impl(T*) const
-    {
-        switch (m_type)
-        {
-            case value_t::number_integer:
-            {
-                return static_cast<T>(m_value.number_integer);
-            }
-
-            case value_t::number_unsigned:
-            {
-                return static_cast<T>(m_value.number_unsigned);
-            }
-
-            case value_t::number_float:
-            {
-                return static_cast<T>(m_value.number_float);
-            }
-
-            default:
-            {
-                throw std::domain_error("type must be number, but is " + type_name());
-            }
-        }
-    }
+    //////////////////
 
     /// get a boolean (explicit)
-    constexpr boolean_t get_impl(boolean_t*) const
+    boolean_t get_impl(boolean_t* /*unused*/) const
     {
-        return is_boolean()
-               ? m_value.boolean
-               : throw std::domain_error("type must be boolean, but is " + type_name());
+        if (is_boolean())
+        {
+            return m_value.boolean;
+        }
+
+        JSON_THROW(type_error::create(302, "type must be boolean, but is " + type_name()));
     }
 
     /// get a pointer to the value (object)
-    object_t* get_impl_ptr(object_t*) noexcept
+    object_t* get_impl_ptr(object_t* /*unused*/) noexcept
     {
         return is_object() ? m_value.object : nullptr;
     }
 
     /// get a pointer to the value (object)
-    constexpr const object_t* get_impl_ptr(const object_t*) const noexcept
+    constexpr const object_t* get_impl_ptr(const object_t* /*unused*/) const noexcept
     {
         return is_object() ? m_value.object : nullptr;
     }
 
     /// get a pointer to the value (array)
-    array_t* get_impl_ptr(array_t*) noexcept
+    array_t* get_impl_ptr(array_t* /*unused*/) noexcept
     {
         return is_array() ? m_value.array : nullptr;
     }
 
     /// get a pointer to the value (array)
-    constexpr const array_t* get_impl_ptr(const array_t*) const noexcept
+    constexpr const array_t* get_impl_ptr(const array_t* /*unused*/) const noexcept
     {
         return is_array() ? m_value.array : nullptr;
     }
 
     /// get a pointer to the value (string)
-    string_t* get_impl_ptr(string_t*) noexcept
+    string_t* get_impl_ptr(string_t* /*unused*/) noexcept
     {
         return is_string() ? m_value.string : nullptr;
     }
 
     /// get a pointer to the value (string)
-    constexpr const string_t* get_impl_ptr(const string_t*) const noexcept
+    constexpr const string_t* get_impl_ptr(const string_t* /*unused*/) const noexcept
     {
         return is_string() ? m_value.string : nullptr;
     }
 
     /// get a pointer to the value (boolean)
-    boolean_t* get_impl_ptr(boolean_t*) noexcept
+    boolean_t* get_impl_ptr(boolean_t* /*unused*/) noexcept
     {
         return is_boolean() ? &m_value.boolean : nullptr;
     }
 
     /// get a pointer to the value (boolean)
-    constexpr const boolean_t* get_impl_ptr(const boolean_t*) const noexcept
+    constexpr const boolean_t* get_impl_ptr(const boolean_t* /*unused*/) const noexcept
     {
         return is_boolean() ? &m_value.boolean : nullptr;
     }
 
     /// get a pointer to the value (integer number)
-    number_integer_t* get_impl_ptr(number_integer_t*) noexcept
+    number_integer_t* get_impl_ptr(number_integer_t* /*unused*/) noexcept
     {
         return is_number_integer() ? &m_value.number_integer : nullptr;
     }
 
     /// get a pointer to the value (integer number)
-    constexpr const number_integer_t* get_impl_ptr(const number_integer_t*) const noexcept
+    constexpr const number_integer_t* get_impl_ptr(const number_integer_t* /*unused*/) const noexcept
     {
         return is_number_integer() ? &m_value.number_integer : nullptr;
     }
 
     /// get a pointer to the value (unsigned number)
-    number_unsigned_t* get_impl_ptr(number_unsigned_t*) noexcept
+    number_unsigned_t* get_impl_ptr(number_unsigned_t* /*unused*/) noexcept
     {
         return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
     }
 
     /// get a pointer to the value (unsigned number)
-    constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t*) const noexcept
+    constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t* /*unused*/) const noexcept
     {
         return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
     }
 
     /// get a pointer to the value (floating-point number)
-    number_float_t* get_impl_ptr(number_float_t*) noexcept
+    number_float_t* get_impl_ptr(number_float_t* /*unused*/) noexcept
     {
         return is_number_float() ? &m_value.number_float : nullptr;
     }
 
     /// get a pointer to the value (floating-point number)
-    constexpr const number_float_t* get_impl_ptr(const number_float_t*) const noexcept
+    constexpr const number_float_t* get_impl_ptr(const number_float_t* /*unused*/) const noexcept
     {
         return is_number_float() ? &m_value.number_float : nullptr;
     }
@@ -2829,7 +3367,7 @@ class basic_json
 
     @tparam ThisType will be deduced as `basic_json` or `const basic_json`
 
-    @throw std::domain_error if ReferenceType does not match underlying value
+    @throw type_error.303 if ReferenceType does not match underlying value
     type of the current JSON
     */
     template<typename ReferenceType, typename ThisType>
@@ -2845,34 +3383,68 @@ class basic_json
         {
             return *ptr;
         }
-        else
-        {
-            throw std::domain_error("incompatible ReferenceType for get_ref, actual type is " +
-                                    obj.type_name());
-        }
+
+        JSON_THROW(type_error::create(303, "incompatible ReferenceType for get_ref, actual type is " + obj.type_name()));
     }
 
   public:
-
     /// @name value access
     /// Direct access to the stored value of a JSON value.
     /// @{
 
+    /*!
+    @brief get special-case overload
+
+    This overloads avoids a lot of template boilerplate, it can be seen as the
+    identity method
+
+    @tparam BasicJsonType == @ref basic_json
+
+    @return a copy of *this
+
+    @complexity Constant.
+
+    @since version 2.1.0
+    */
+    template <
+        typename BasicJsonType,
+        detail::enable_if_t<std::is_same<typename std::remove_const<BasicJsonType>::type,
+                                         basic_json_t>::value,
+                            int> = 0 >
+    basic_json get() const
+    {
+        return *this;
+    }
+
     /*!
     @brief get a value (explicit)
 
-    Explicit type conversion between the JSON value and a compatible value.
+    Explicit type conversion between the JSON value and a compatible value
+    which is [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible)
+    and [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible).
+    The value is converted by calling the @ref json_serializer<ValueType>
+    `from_json()` method.
 
-    @tparam ValueType non-pointer type compatible to the JSON value, for
-    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
-    `std::vector` types for JSON arrays
+    The function is equivalent to executing
+    @code {.cpp}
+    ValueType ret;
+    JSONSerializer<ValueType>::from_json(*this, ret);
+    return ret;
+    @endcode
 
-    @return copy of the JSON value, converted to type @a ValueType
+    This overloads is chosen if:
+    - @a ValueType is not @ref basic_json,
+    - @ref json_serializer<ValueType> has a `from_json()` method of the form
+      `void from_json(const @ref basic_json&, ValueType&)`, and
+    - @ref json_serializer<ValueType> does not have a `from_json()` method of
+      the form `ValueType from_json(const @ref basic_json&)`
 
-    @throw std::domain_error in case passed type @a ValueType is incompatible
-    to JSON; example: `"type must be object, but is null"`
+    @tparam ValueTypeCV the provided value type
+    @tparam ValueType the returned value type
 
-    @complexity Linear in the size of the JSON value.
+    @return copy of the JSON value, converted to @a ValueType
+
+    @throw what @ref json_serializer<ValueType> `from_json()` method throws
 
     @liveexample{The example below shows several conversions from JSON values
     to other types. There a few things to note: (1) Floating-point numbers can
@@ -2881,21 +3453,75 @@ class basic_json
     associative containers such as `std::unordered_map<std::string\,
     json>`.,get__ValueType_const}
 
-    @internal
-    The idea of using a casted null pointer to choose the correct
-    implementation is from <http://stackoverflow.com/a/8315197/266378>.
-    @endinternal
+    @since version 2.1.0
+    */
+    template <
+        typename ValueTypeCV,
+        typename ValueType = detail::uncvref_t<ValueTypeCV>,
+        detail::enable_if_t <
+            not std::is_same<basic_json_t, ValueType>::value and
+            detail::has_from_json<basic_json_t, ValueType>::value and
+            not detail::has_non_default_from_json<basic_json_t, ValueType>::value,
+            int > = 0 >
+    ValueType get() const noexcept(noexcept(
+                                       JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), std::declval<ValueType&>())))
+    {
+        // we cannot static_assert on ValueTypeCV being non-const, because
+        // there is support for get<const basic_json_t>(), which is why we
+        // still need the uncvref
+        static_assert(not std::is_reference<ValueTypeCV>::value,
+                      "get() cannot be used with reference types, you might want to use get_ref()");
+        static_assert(std::is_default_constructible<ValueType>::value,
+                      "types must be DefaultConstructible when used with get()");
 
-    @sa @ref operator ValueType() const for implicit conversion
-    @sa @ref get() for pointer-member access
+        ValueType ret;
+        JSONSerializer<ValueType>::from_json(*this, ret);
+        return ret;
+    }
 
-    @since version 1.0.0
+    /*!
+    @brief get a value (explicit); special case
+
+    Explicit type conversion between the JSON value and a compatible value
+    which is **not** [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible)
+    and **not** [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible).
+    The value is converted by calling the @ref json_serializer<ValueType>
+    `from_json()` method.
+
+    The function is equivalent to executing
+    @code {.cpp}
+    return JSONSerializer<ValueTypeCV>::from_json(*this);
+    @endcode
+
+    This overloads is chosen if:
+    - @a ValueType is not @ref basic_json and
+    - @ref json_serializer<ValueType> has a `from_json()` method of the form
+      `ValueType from_json(const @ref basic_json&)`
+
+    @note If @ref json_serializer<ValueType> has both overloads of
+    `from_json()`, this one is chosen.
+
+    @tparam ValueTypeCV the provided value type
+    @tparam ValueType the returned value type
+
+    @return copy of the JSON value, converted to @a ValueType
+
+    @throw what @ref json_serializer<ValueType> `from_json()` method throws
+
+    @since version 2.1.0
     */
-    template<typename ValueType, typename std::enable_if<
-                 not std::is_pointer<ValueType>::value, int>::type = 0>
-    ValueType get() const
+    template <
+        typename ValueTypeCV,
+        typename ValueType = detail::uncvref_t<ValueTypeCV>,
+        detail::enable_if_t<not std::is_same<basic_json_t, ValueType>::value and
+                            detail::has_non_default_from_json<basic_json_t,
+                                    ValueType>::value, int> = 0 >
+    ValueType get() const noexcept(noexcept(
+                                       JSONSerializer<ValueTypeCV>::from_json(std::declval<const basic_json_t&>())))
     {
-        return get_impl(static_cast<ValueType*>(nullptr));
+        static_assert(not std::is_reference<ValueTypeCV>::value,
+                      "get() cannot be used with reference types, you might want to use get_ref()");
+        return JSONSerializer<ValueTypeCV>::from_json(*this);
     }
 
     /*!
@@ -3025,7 +3651,7 @@ class basic_json
     /*!
     @brief get a reference value (implicit)
 
-    Implict reference access to the internally stored JSON value. No copies
+    Implicit reference access to the internally stored JSON value. No copies
     are made.
 
     @warning Writing data to the referee of the result yields an undefined
@@ -3037,10 +3663,10 @@ class basic_json
 
     @return reference to the internally stored JSON value if the requested
     reference type @a ReferenceType fits to the JSON value; throws
-    std::domain_error otherwise
+    type_error.303 otherwise
 
-    @throw std::domain_error in case passed type @a ReferenceType is
-    incompatible with the stored JSON value
+    @throw type_error.303 in case passed type @a ReferenceType is incompatible
+    with the stored JSON value; see example below
 
     @complexity Constant.
 
@@ -3083,8 +3709,9 @@ class basic_json
 
     @return copy of the JSON value, converted to type @a ValueType
 
-    @throw std::domain_error in case passed type @a ValueType is incompatible
-    to JSON, thrown by @ref get() const
+    @throw type_error.302 in case passed type @a ValueType is incompatible
+    to the JSON value type (e.g., the JSON value is of type boolean, but a
+    string is requested); see example below
 
     @complexity Linear in the size of the JSON value.
 
@@ -3100,8 +3727,11 @@ class basic_json
     template < typename ValueType, typename std::enable_if <
                    not std::is_pointer<ValueType>::value and
                    not std::is_same<ValueType, typename string_t::value_type>::value
-#ifndef _MSC_VER  // Fix for issue #167 operator<< abiguity under VS2015
+#ifndef _MSC_VER  // fix for issue #167 operator<< ambiguity under VS2015
                    and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
+#endif
+#if defined(_MSC_VER) && _MSC_VER >1900 && defined(_HAS_CXX17) && _HAS_CXX17 == 1 // fix for issue #464
+                   and not std::is_same<ValueType, typename std::string_view>::value
 #endif
                    , int >::type = 0 >
     operator ValueType() const
@@ -3131,36 +3761,40 @@ class basic_json
 
     @return reference to the element at index @a idx
 
-    @throw std::domain_error if the JSON value is not an array; example:
-    `"cannot use at() with string"`
-    @throw std::out_of_range if the index @a idx is out of range of the array;
-    that is, `idx >= size()`; example: `"array index 7 is out of range"`
+    @throw type_error.304 if the JSON value is not an array; in this case,
+    calling `at` with an index makes no sense. See example below.
+    @throw out_of_range.401 if the index @a idx is out of range of the array;
+    that is, `idx >= size()`. See example below.
 
-    @complexity Constant.
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-    @liveexample{The example below shows how array elements can be read and
-    written using `at()`.,at__size_type}
+    @complexity Constant.
 
     @since version 1.0.0
+
+    @liveexample{The example below shows how array elements can be read and
+    written using `at()`. It also demonstrates the different exceptions that
+    can be thrown.,at__size_type}
     */
     reference at(size_type idx)
     {
         // at only works for arrays
         if (is_array())
         {
-            try
+            JSON_TRY
             {
                 return m_value.array->at(idx);
             }
-            catch (std::out_of_range&)
+            JSON_CATCH (std::out_of_range&)
             {
                 // create better exception explanation
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
             }
         }
         else
         {
-            throw std::domain_error("cannot use at() with " + type_name());
+            JSON_THROW(type_error::create(304, "cannot use at() with " + type_name()));
         }
     }
 
@@ -3174,36 +3808,40 @@ class basic_json
 
     @return const reference to the element at index @a idx
 
-    @throw std::domain_error if the JSON value is not an array; example:
-    `"cannot use at() with string"`
-    @throw std::out_of_range if the index @a idx is out of range of the array;
-    that is, `idx >= size()`; example: `"array index 7 is out of range"`
+    @throw type_error.304 if the JSON value is not an array; in this case,
+    calling `at` with an index makes no sense. See example below.
+    @throw out_of_range.401 if the index @a idx is out of range of the array;
+    that is, `idx >= size()`. See example below.
 
-    @complexity Constant.
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-    @liveexample{The example below shows how array elements can be read using
-    `at()`.,at__size_type_const}
+    @complexity Constant.
 
     @since version 1.0.0
+
+    @liveexample{The example below shows how array elements can be read using
+    `at()`. It also demonstrates the different exceptions that can be thrown.,
+    at__size_type_const}
     */
     const_reference at(size_type idx) const
     {
         // at only works for arrays
         if (is_array())
         {
-            try
+            JSON_TRY
             {
                 return m_value.array->at(idx);
             }
-            catch (std::out_of_range&)
+            JSON_CATCH (std::out_of_range&)
             {
                 // create better exception explanation
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
             }
         }
         else
         {
-            throw std::domain_error("cannot use at() with " + type_name());
+            JSON_THROW(type_error::create(304, "cannot use at() with " + type_name()));
         }
     }
 
@@ -3217,40 +3855,44 @@ class basic_json
 
     @return reference to the element at key @a key
 
-    @throw std::domain_error if the JSON value is not an object; example:
-    `"cannot use at() with boolean"`
-    @throw std::out_of_range if the key @a key is is not stored in the object;
-    that is, `find(key) == end()`; example: `"key "the fast" not found"`
+    @throw type_error.304 if the JSON value is not an object; in this case,
+    calling `at` with a key makes no sense. See example below.
+    @throw out_of_range.403 if the key @a key is is not stored in the object;
+    that is, `find(key) == end()`. See example below.
 
-    @complexity Logarithmic in the size of the container.
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-    @liveexample{The example below shows how object elements can be read and
-    written using `at()`.,at__object_t_key_type}
+    @complexity Logarithmic in the size of the container.
 
     @sa @ref operator[](const typename object_t::key_type&) for unchecked
     access by reference
     @sa @ref value() for access by value with a default value
 
     @since version 1.0.0
+
+    @liveexample{The example below shows how object elements can be read and
+    written using `at()`. It also demonstrates the different exceptions that
+    can be thrown.,at__object_t_key_type}
     */
     reference at(const typename object_t::key_type& key)
     {
         // at only works for objects
         if (is_object())
         {
-            try
+            JSON_TRY
             {
                 return m_value.object->at(key);
             }
-            catch (std::out_of_range&)
+            JSON_CATCH (std::out_of_range&)
             {
                 // create better exception explanation
-                throw std::out_of_range("key '" + key + "' not found");
+                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
             }
         }
         else
         {
-            throw std::domain_error("cannot use at() with " + type_name());
+            JSON_THROW(type_error::create(304, "cannot use at() with " + type_name()));
         }
     }
 
@@ -3264,40 +3906,44 @@ class basic_json
 
     @return const reference to the element at key @a key
 
-    @throw std::domain_error if the JSON value is not an object; example:
-    `"cannot use at() with boolean"`
-    @throw std::out_of_range if the key @a key is is not stored in the object;
-    that is, `find(key) == end()`; example: `"key "the fast" not found"`
+    @throw type_error.304 if the JSON value is not an object; in this case,
+    calling `at` with a key makes no sense. See example below.
+    @throw out_of_range.403 if the key @a key is is not stored in the object;
+    that is, `find(key) == end()`. See example below.
 
-    @complexity Logarithmic in the size of the container.
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-    @liveexample{The example below shows how object elements can be read using
-    `at()`.,at__object_t_key_type_const}
+    @complexity Logarithmic in the size of the container.
 
     @sa @ref operator[](const typename object_t::key_type&) for unchecked
     access by reference
     @sa @ref value() for access by value with a default value
 
     @since version 1.0.0
+
+    @liveexample{The example below shows how object elements can be read using
+    `at()`. It also demonstrates the different exceptions that can be thrown.,
+    at__object_t_key_type_const}
     */
     const_reference at(const typename object_t::key_type& key) const
     {
         // at only works for objects
         if (is_object())
         {
-            try
+            JSON_TRY
             {
                 return m_value.object->at(key);
             }
-            catch (std::out_of_range&)
+            JSON_CATCH (std::out_of_range&)
             {
                 // create better exception explanation
-                throw std::out_of_range("key '" + key + "' not found");
+                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
             }
         }
         else
         {
-            throw std::domain_error("cannot use at() with " + type_name());
+            JSON_THROW(type_error::create(304, "cannot use at() with " + type_name()));
         }
     }
 
@@ -3314,8 +3960,8 @@ class basic_json
 
     @return reference to the element at index @a idx
 
-    @throw std::domain_error if JSON is not an array or null; example:
-    `"cannot use operator[] with string"`
+    @throw type_error.305 if the JSON value is not an array or null; in that
+    cases, using the [] operator with an index makes no sense.
 
     @complexity Constant if @a idx is in the range of the array. Otherwise
     linear in `idx - size()`.
@@ -3349,10 +3995,8 @@ class basic_json
 
             return m_value.array->operator[](idx);
         }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
     }
 
     /*!
@@ -3364,8 +4008,8 @@ class basic_json
 
     @return const reference to the element at index @a idx
 
-    @throw std::domain_error if JSON is not an array; example: `"cannot use
-    operator[] with null"`
+    @throw type_error.305 if the JSON value is not an array; in that cases,
+    using the [] operator with an index makes no sense.
 
     @complexity Constant.
 
@@ -3381,10 +4025,8 @@ class basic_json
         {
             return m_value.array->operator[](idx);
         }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
     }
 
     /*!
@@ -3400,8 +4042,8 @@ class basic_json
 
     @return reference to the element at key @a key
 
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
+    @throw type_error.305 if the JSON value is not an object or null; in that
+    cases, using the [] operator with a key makes no sense.
 
     @complexity Logarithmic in the size of the container.
 
@@ -3429,10 +4071,8 @@ class basic_json
         {
             return m_value.object->operator[](key);
         }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
     }
 
     /*!
@@ -3451,8 +4091,8 @@ class basic_json
     @pre The element with key @a key must exist. **This precondition is
          enforced with an assertion.**
 
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
+    @throw type_error.305 if the JSON value is not an object; in that cases,
+    using the [] operator with a key makes no sense.
 
     @complexity Logarithmic in the size of the container.
 
@@ -3473,10 +4113,8 @@ class basic_json
             assert(m_value.object->find(key) != m_value.object->end());
             return m_value.object->find(key)->second;
         }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
     }
 
     /*!
@@ -3492,8 +4130,8 @@ class basic_json
 
     @return reference to the element at key @a key
 
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
+    @throw type_error.305 if the JSON value is not an object or null; in that
+    cases, using the [] operator with a key makes no sense.
 
     @complexity Logarithmic in the size of the container.
 
@@ -3527,8 +4165,8 @@ class basic_json
 
     @return const reference to the element at key @a key
 
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
+    @throw type_error.305 if the JSON value is not an object; in that cases,
+    using the [] operator with a key makes no sense.
 
     @complexity Logarithmic in the size of the container.
 
@@ -3560,8 +4198,8 @@ class basic_json
 
     @return reference to the element at key @a key
 
-    @throw std::domain_error if JSON is not an object or null; example:
-    `"cannot use operator[] with string"`
+    @throw type_error.305 if the JSON value is not an object or null; in that
+    cases, using the [] operator with a key makes no sense.
 
     @complexity Logarithmic in the size of the container.
 
@@ -3590,10 +4228,8 @@ class basic_json
         {
             return m_value.object->operator[](key);
         }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
     }
 
     /*!
@@ -3612,8 +4248,8 @@ class basic_json
     @pre The element with key @a key must exist. **This precondition is
          enforced with an assertion.**
 
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    operator[] with null"`
+    @throw type_error.305 if the JSON value is not an object; in that cases,
+    using the [] operator with a key makes no sense.
 
     @complexity Logarithmic in the size of the container.
 
@@ -3635,10 +4271,8 @@ class basic_json
             assert(m_value.object->find(key) != m_value.object->end());
             return m_value.object->find(key)->second;
         }
-        else
-        {
-            throw std::domain_error("cannot use operator[] with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
     }
 
     /*!
@@ -3651,7 +4285,7 @@ class basic_json
     @code {.cpp}
     try {
         return at(key);
-    } catch(std::out_of_range) {
+    } catch(out_of_range) {
         return default_value;
     }
     @endcode
@@ -3674,8 +4308,8 @@ class basic_json
     @return copy of the element at key @a key or @a default_value if @a key
     is not found
 
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    value() with null"`
+    @throw type_error.306 if the JSON value is not an objec; in that cases,
+    using `value()` with a key makes no sense.
 
     @complexity Logarithmic in the size of the container.
 
@@ -3702,14 +4336,12 @@ class basic_json
             {
                 return *it;
             }
-            else
-            {
-                return default_value;
-            }
+
+            return default_value;
         }
         else
         {
-            throw std::domain_error("cannot use value() with " + type_name());
+            JSON_THROW(type_error::create(306, "cannot use value() with " + type_name()));
         }
     }
 
@@ -3732,7 +4364,7 @@ class basic_json
     @code {.cpp}
     try {
         return at(ptr);
-    } catch(std::out_of_range) {
+    } catch(out_of_range) {
         return default_value;
     }
     @endcode
@@ -3751,8 +4383,8 @@ class basic_json
     @return copy of the element at key @a key or @a default_value if @a key
     is not found
 
-    @throw std::domain_error if JSON is not an object; example: `"cannot use
-    value() with null"`
+    @throw type_error.306 if the JSON value is not an objec; in that cases,
+    using `value()` with a key makes no sense.
 
     @complexity Logarithmic in the size of the container.
 
@@ -3771,19 +4403,17 @@ class basic_json
         if (is_object())
         {
             // if pointer resolves a value, return it or use default value
-            try
+            JSON_TRY
             {
                 return ptr.get_checked(this);
             }
-            catch (std::out_of_range&)
+            JSON_CATCH (out_of_range&)
             {
                 return default_value;
             }
         }
-        else
-        {
-            throw std::domain_error("cannot use value() with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(306, "cannot use value() with " + type_name()));
     }
 
     /*!
@@ -3812,7 +4442,7 @@ class basic_json
     assertions**).
     @post The JSON value remains unchanged.
 
-    @throw std::out_of_range when called on `null` value
+    @throw invalid_iterator.214 when called on `null` value
 
     @liveexample{The following code shows an example for `front()`.,front}
 
@@ -3855,7 +4485,8 @@ class basic_json
     assertions**).
     @post The JSON value remains unchanged.
 
-    @throw std::out_of_range when called on `null` value.
+    @throw invalid_iterator.214 when called on a `null` value. See example
+    below.
 
     @liveexample{The following code shows an example for `back()`.,back}
 
@@ -3899,17 +4530,18 @@ class basic_json
     @post Invalidates iterators and references at or after the point of the
     erase, including the `end()` iterator.
 
-    @throw std::domain_error if called on a `null` value; example: `"cannot
-    use erase() with null"`
-    @throw std::domain_error if called on an iterator which does not belong to
-    the current JSON value; example: `"iterator does not fit current value"`
-    @throw std::out_of_range if called on a primitive type with invalid
+    @throw type_error.307 if called on a `null` value; example: `"cannot use
+    erase() with null"`
+    @throw invalid_iterator.202 if called on an iterator which does not belong
+    to the current JSON value; example: `"iterator does not fit current
+    value"`
+    @throw invalid_iterator.205 if called on a primitive type with invalid
     iterator (i.e., any iterator which is not `begin()`); example: `"iterator
     out of range"`
 
     @complexity The complexity depends on the type:
     - objects: amortized constant
-    - arrays: linear in distance between pos and the end of the container
+    - arrays: linear in distance between @a pos and the end of the container
     - strings: linear in the length of the string
     - other types: constant
 
@@ -3934,7 +4566,7 @@ class basic_json
         // make sure iterator fits the current value
         if (this != pos.m_object)
         {
-            throw std::domain_error("iterator does not fit current value");
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
         }
 
         IteratorType result = end();
@@ -3949,7 +4581,7 @@ class basic_json
             {
                 if (not pos.m_it.primitive_iterator.is_begin())
                 {
-                    throw std::out_of_range("iterator out of range");
+                    JSON_THROW(invalid_iterator::create(205, "iterator out of range"));
                 }
 
                 if (is_string())
@@ -3979,7 +4611,7 @@ class basic_json
 
             default:
             {
-                throw std::domain_error("cannot use erase() with " + type_name());
+                JSON_THROW(type_error::create(307, "cannot use erase() with " + type_name()));
             }
         }
 
@@ -4006,11 +4638,11 @@ class basic_json
     @post Invalidates iterators and references at or after the point of the
     erase, including the `end()` iterator.
 
-    @throw std::domain_error if called on a `null` value; example: `"cannot
-    use erase() with null"`
-    @throw std::domain_error if called on iterators which does not belong to
-    the current JSON value; example: `"iterators do not fit current value"`
-    @throw std::out_of_range if called on a primitive type with invalid
+    @throw type_error.307 if called on a `null` value; example: `"cannot use
+    erase() with null"`
+    @throw invalid_iterator.203 if called on iterators which does not belong
+    to the current JSON value; example: `"iterators do not fit current value"`
+    @throw invalid_iterator.204 if called on a primitive type with invalid
     iterators (i.e., if `first != begin()` and `last != end()`); example:
     `"iterators out of range"`
 
@@ -4041,7 +4673,7 @@ class basic_json
         // make sure iterator fits the current value
         if (this != first.m_object or this != last.m_object)
         {
-            throw std::domain_error("iterators do not fit current value");
+            JSON_THROW(invalid_iterator::create(203, "iterators do not fit current value"));
         }
 
         IteratorType result = end();
@@ -4056,7 +4688,7 @@ class basic_json
             {
                 if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
                 {
-                    throw std::out_of_range("iterators out of range");
+                    JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
                 }
 
                 if (is_string())
@@ -4088,7 +4720,7 @@ class basic_json
 
             default:
             {
-                throw std::domain_error("cannot use erase() with " + type_name());
+                JSON_THROW(type_error::create(307, "cannot use erase() with " + type_name()));
             }
         }
 
@@ -4109,7 +4741,7 @@ class basic_json
     @post References and iterators to the erased elements are invalidated.
     Other references and iterators are not affected.
 
-    @throw std::domain_error when called on a type other than JSON object;
+    @throw type_error.307 when called on a type other than JSON object;
     example: `"cannot use erase() with null"`
 
     @complexity `log(size()) + count(key)`
@@ -4131,10 +4763,8 @@ class basic_json
         {
             return m_value.object->erase(key);
         }
-        else
-        {
-            throw std::domain_error("cannot use erase() with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(307, "cannot use erase() with " + type_name()));
     }
 
     /*!
@@ -4144,9 +4774,9 @@ class basic_json
 
     @param[in] idx index of the element to remove
 
-    @throw std::domain_error when called on a type other than JSON array;
+    @throw type_error.307 when called on a type other than JSON object;
     example: `"cannot use erase() with null"`
-    @throw std::out_of_range when `idx >= size()`; example: `"array index 17
+    @throw out_of_range.401 when `idx >= size()`; example: `"array index 17
     is out of range"`
 
     @complexity Linear in distance between @a idx and the end of the container.
@@ -4168,14 +4798,14 @@ class basic_json
         {
             if (idx >= size())
             {
-                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
             }
 
             m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
         }
         else
         {
-            throw std::domain_error("cannot use erase() with " + type_name());
+            JSON_THROW(type_error::create(307, "cannot use erase() with " + type_name()));
         }
     }
 
@@ -4877,7 +5507,7 @@ class basic_json
 
     @param[in] val the value to add to the JSON array
 
-    @throw std::domain_error when called on a type other than JSON array or
+    @throw type_error.308 when called on a type other than JSON array or
     null; example: `"cannot use push_back() with number"`
 
     @complexity Amortized constant.
@@ -4893,7 +5523,7 @@ class basic_json
         // push_back only works for null objects or arrays
         if (not(is_null() or is_array()))
         {
-            throw std::domain_error("cannot use push_back() with " + type_name());
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + type_name()));
         }
 
         // transform null object into an array
@@ -4929,7 +5559,7 @@ class basic_json
         // push_back only works for null objects or arrays
         if (not(is_null() or is_array()))
         {
-            throw std::domain_error("cannot use push_back() with " + type_name());
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + type_name()));
         }
 
         // transform null object into an array
@@ -4963,7 +5593,7 @@ class basic_json
 
     @param[in] val the value to add to the JSON object
 
-    @throw std::domain_error when called on a type other than JSON object or
+    @throw type_error.308 when called on a type other than JSON object or
     null; example: `"cannot use push_back() with number"`
 
     @complexity Logarithmic in the size of the container, O(log(`size()`)).
@@ -4979,7 +5609,7 @@ class basic_json
         // push_back only works for null objects or objects
         if (not(is_null() or is_object()))
         {
-            throw std::domain_error("cannot use push_back() with " + type_name());
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + type_name()));
         }
 
         // transform null object into an object
@@ -5017,7 +5647,7 @@ class basic_json
     @ref push_back(const typename object_t::value_type&). Otherwise, @a init
     is converted to a JSON value and added using @ref push_back(basic_json&&).
 
-    @param init  an initializer list
+    @param[in] init  an initializer list
 
     @complexity Linear in the size of the initializer list @a init.
 
@@ -5062,7 +5692,7 @@ class basic_json
     @param[in] args arguments to forward to a constructor of @ref basic_json
     @tparam Args compatible types to create a @ref basic_json object
 
-    @throw std::domain_error when called on a type other than JSON array or
+    @throw type_error.311 when called on a type other than JSON array or
     null; example: `"cannot use emplace_back() with number"`
 
     @complexity Amortized constant.
@@ -5079,7 +5709,7 @@ class basic_json
         // emplace_back only works for null objects or arrays
         if (not(is_null() or is_array()))
         {
-            throw std::domain_error("cannot use emplace_back() with " + type_name());
+            JSON_THROW(type_error::create(311, "cannot use emplace_back() with " + type_name()));
         }
 
         // transform null object into an array
@@ -5097,8 +5727,8 @@ class basic_json
     /*!
     @brief add an object to an object if key does not exist
 
-    Inserts a new element into a JSON object constructed in-place with the given
-    @a args if there is no element with the key in the container. If the
+    Inserts a new element into a JSON object constructed in-place with the
+    given @a args if there is no element with the key in the container. If the
     function is called on a JSON null value, an empty object is created before
     appending the value created from @a args.
 
@@ -5109,7 +5739,7 @@ class basic_json
             already-existing element if no insertion happened, and a bool
             denoting whether the insertion took place.
 
-    @throw std::domain_error when called on a type other than JSON object or
+    @throw type_error.311 when called on a type other than JSON object or
     null; example: `"cannot use emplace() with number"`
 
     @complexity Logarithmic in the size of the container, O(log(`size()`)).
@@ -5127,7 +5757,7 @@ class basic_json
         // emplace only works for null objects or arrays
         if (not(is_null() or is_object()))
         {
-            throw std::domain_error("cannot use emplace() with " + type_name());
+            JSON_THROW(type_error::create(311, "cannot use emplace() with " + type_name()));
         }
 
         // transform null object into an object
@@ -5158,13 +5788,13 @@ class basic_json
     @param[in] val element to insert
     @return iterator pointing to the inserted @a val.
 
-    @throw std::domain_error if called on JSON values other than arrays;
+    @throw type_error.309 if called on JSON values other than arrays;
     example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
+    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
+    example: `"iterator does not fit current value"`
 
-    @complexity Constant plus linear in the distance between pos and end of the
-    container.
+    @complexity Constant plus linear in the distance between @a pos and end of
+    the container.
 
     @liveexample{The example shows how `insert()` is used.,insert}
 
@@ -5178,7 +5808,7 @@ class basic_json
             // check if iterator pos fits to this JSON value
             if (pos.m_object != this)
             {
-                throw std::domain_error("iterator does not fit current value");
+                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
             }
 
             // insert to array and return iterator
@@ -5186,10 +5816,8 @@ class basic_json
             result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
             return result;
         }
-        else
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
     }
 
     /*!
@@ -5213,10 +5841,10 @@ class basic_json
     @return iterator pointing to the first element inserted, or @a pos if
     `cnt==0`
 
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
+    @throw type_error.309 if called on JSON values other than arrays; example:
+    `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
+    example: `"iterator does not fit current value"`
 
     @complexity Linear in @a cnt plus linear in the distance between @a pos
     and end of the container.
@@ -5233,7 +5861,7 @@ class basic_json
             // check if iterator pos fits to this JSON value
             if (pos.m_object != this)
             {
-                throw std::domain_error("iterator does not fit current value");
+                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
             }
 
             // insert to array and return iterator
@@ -5241,10 +5869,8 @@ class basic_json
             result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
             return result;
         }
-        else
-        {
-            throw std::domain_error("cannot use insert() with " + type_name());
-        }
+
+        JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
     }
 
     /*!
@@ -5257,13 +5883,13 @@ class basic_json
     @param[in] first begin of the range of elements to insert
     @param[in] last end of the range of elements to insert
 
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
-    @throw std::domain_error if @a first and @a last do not belong to the same
-    JSON value; example: `"iterators do not fit"`
-    @throw std::domain_error if @a first or @a last are iterators into
+    @throw type_error.309 if called on JSON values other than arrays; example:
+    `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
+    example: `"iterator does not fit current value"`
+    @throw invalid_iterator.210 if @a first and @a last do not belong to the
+    same JSON value; example: `"iterators do not fit"`
+    @throw invalid_iterator.211 if @a first or @a last are iterators into
     container for which insert is called; example: `"passed iterators may not
     belong to container"`
 
@@ -5282,24 +5908,24 @@ class basic_json
         // insert only works for arrays
         if (not is_array())
         {
-            throw std::domain_error("cannot use insert() with " + type_name());
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
         }
 
         // check if iterator pos fits to this JSON value
         if (pos.m_object != this)
         {
-            throw std::domain_error("iterator does not fit current value");
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
         }
 
         // check if range iterators belong to the same JSON object
         if (first.m_object != last.m_object)
         {
-            throw std::domain_error("iterators do not fit");
+            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
         }
 
         if (first.m_object == this or last.m_object == this)
         {
-            throw std::domain_error("passed iterators may not belong to container");
+            JSON_THROW(invalid_iterator::create(211, "passed iterators may not belong to container"));
         }
 
         // insert to array and return iterator
@@ -5320,10 +5946,10 @@ class basic_json
     the end() iterator
     @param[in] ilist initializer list to insert the values from
 
-    @throw std::domain_error if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw std::domain_error if @a pos is not an iterator of *this; example:
-    `"iterator does not fit current value"`
+    @throw type_error.309 if called on JSON values other than arrays; example:
+    `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
+    example: `"iterator does not fit current value"`
 
     @return iterator pointing to the first element inserted, or @a pos if
     `ilist` is empty
@@ -5340,13 +5966,13 @@ class basic_json
         // insert only works for arrays
         if (not is_array())
         {
-            throw std::domain_error("cannot use insert() with " + type_name());
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
         }
 
         // check if iterator pos fits to this JSON value
         if (pos.m_object != this)
         {
-            throw std::domain_error("iterator does not fit current value");
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
         }
 
         // insert to array and return iterator
@@ -5355,6 +5981,52 @@ class basic_json
         return result;
     }
 
+    /*!
+    @brief inserts elements
+
+    Inserts elements from range `[first, last)`.
+
+    @param[in] first begin of the range of elements to insert
+    @param[in] last end of the range of elements to insert
+
+    @throw type_error.309 if called on JSON values other than objects; example:
+    `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if iterator @a first or @a last does does not
+    point to an object; example: `"iterators first and last must point to
+    objects"`
+    @throw invalid_iterator.210 if @a first and @a last do not belong to the
+    same JSON value; example: `"iterators do not fit"`
+
+    @complexity Logarithmic: `O(N*log(size() + N))`, where `N` is the number
+    of elements to insert.
+
+    @liveexample{The example shows how `insert()` is used.,insert__range_object}
+
+    @since version 3.0.0
+    */
+    void insert(const_iterator first, const_iterator last)
+    {
+        // insert only works for objects
+        if (not is_object())
+        {
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
+        }
+
+        // check if range iterators belong to the same JSON object
+        if (first.m_object != last.m_object)
+        {
+            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
+        }
+
+        // passed iterators must belong to objects
+        if (not first.m_object->is_object() or not first.m_object->is_object())
+        {
+            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects"));
+        }
+
+        m_value.object->insert(first.m_it.object_iterator, last.m_it.object_iterator);
+    }
+
     /*!
     @brief exchanges the values
 
@@ -5394,7 +6066,7 @@ class basic_json
 
     @param[in,out] other array to exchange the contents with
 
-    @throw std::domain_error when JSON value is not an array; example: `"cannot
+    @throw type_error.310 when JSON value is not an array; example: `"cannot
     use swap() with string"`
 
     @complexity Constant.
@@ -5413,7 +6085,7 @@ class basic_json
         }
         else
         {
-            throw std::domain_error("cannot use swap() with " + type_name());
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + type_name()));
         }
     }
 
@@ -5427,7 +6099,7 @@ class basic_json
 
     @param[in,out] other object to exchange the contents with
 
-    @throw std::domain_error when JSON value is not an object; example:
+    @throw type_error.310 when JSON value is not an object; example:
     `"cannot use swap() with string"`
 
     @complexity Constant.
@@ -5446,7 +6118,7 @@ class basic_json
         }
         else
         {
-            throw std::domain_error("cannot use swap() with " + type_name());
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + type_name()));
         }
     }
 
@@ -5460,7 +6132,7 @@ class basic_json
 
     @param[in,out] other string to exchange the contents with
 
-    @throw std::domain_error when JSON value is not a string; example: `"cannot
+    @throw type_error.310 when JSON value is not a string; example: `"cannot
     use swap() with boolean"`
 
     @complexity Constant.
@@ -5479,13 +6151,13 @@ class basic_json
         }
         else
         {
-            throw std::domain_error("cannot use swap() with " + type_name());
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + type_name()));
         }
     }
 
     /// @}
 
-
+  public:
     //////////////////////////////////////////
     // lexicographical comparison operators //
     //////////////////////////////////////////
@@ -5493,64 +6165,198 @@ class basic_json
     /// @name lexicographical comparison operators
     /// @{
 
-  private:
     /*!
-    @brief comparison operator for JSON types
+    @brief comparison: equal
+
+    Compares two JSON values for equality according to the following rules:
+    - Two JSON values are equal if (1) they are from the same type and (2)
+      their stored values are the same according to their respective
+      `operator==`.
+    - Integer and floating-point numbers are automatically converted before
+      comparison. Floating-point numbers are compared indirectly: two
+      floating-point numbers `f1` and `f2` are considered equal if neither
+      `f1 > f2` nor `f2 > f1` holds. Note than two NaN values are always
+      treated as unequal.
+    - Two JSON null values are equal.
+
+    @note NaN values never compare equal to themselves or to other NaN values.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether the values @a lhs and @a rhs are equal
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__equal}
+
+    @since version 1.0.0
+    */
+    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
+    {
+        const auto lhs_type = lhs.type();
+        const auto rhs_type = rhs.type();
+
+        if (lhs_type == rhs_type)
+        {
+            switch (lhs_type)
+            {
+                case value_t::array:
+                {
+                    return *lhs.m_value.array == *rhs.m_value.array;
+                }
+                case value_t::object:
+                {
+                    return *lhs.m_value.object == *rhs.m_value.object;
+                }
+                case value_t::null:
+                {
+                    return true;
+                }
+                case value_t::string:
+                {
+                    return *lhs.m_value.string == *rhs.m_value.string;
+                }
+                case value_t::boolean:
+                {
+                    return lhs.m_value.boolean == rhs.m_value.boolean;
+                }
+                case value_t::number_integer:
+                {
+                    return lhs.m_value.number_integer == rhs.m_value.number_integer;
+                }
+                case value_t::number_unsigned:
+                {
+                    return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned;
+                }
+                case value_t::number_float:
+                {
+                    return lhs.m_value.number_float == rhs.m_value.number_float;
+                }
+                default:
+                {
+                    return false;
+                }
+            }
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        {
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        {
+            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer;
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned);
+        }
+
+        return false;
+    }
+
+    /*!
+    @brief comparison: equal
+    @copydoc operator==(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator==(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs == basic_json(rhs));
+    }
+
+    /*!
+    @brief comparison: equal
+    @copydoc operator==(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator==(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) == rhs);
+    }
+
+    /*!
+    @brief comparison: not equal
+
+    Compares two JSON values for inequality by calculating `not (lhs == rhs)`.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether the values @a lhs and @a rhs are not equal
 
-    Returns an ordering that is similar to Python:
-    - order: null < boolean < number < object < array < string
-    - furthermore, each type is not smaller than itself
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__notequal}
 
     @since version 1.0.0
     */
-    friend bool operator<(const value_t lhs, const value_t rhs) noexcept
+    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
     {
-        static constexpr std::array<uint8_t, 8> order = {{
-                0, // null
-                3, // object
-                4, // array
-                5, // string
-                1, // boolean
-                2, // integer
-                2, // unsigned
-                2, // float
-            }
-        };
+        return not (lhs == rhs);
+    }
 
-        // discarded values are not comparable
-        if (lhs == value_t::discarded or rhs == value_t::discarded)
-        {
-            return false;
-        }
+    /*!
+    @brief comparison: not equal
+    @copydoc operator!=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator!=(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs != basic_json(rhs));
+    }
 
-        return order[static_cast<std::size_t>(lhs)] < order[static_cast<std::size_t>(rhs)];
+    /*!
+    @brief comparison: not equal
+    @copydoc operator!=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator!=(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) != rhs);
     }
 
-  public:
     /*!
-    @brief comparison: equal
+    @brief comparison: less than
 
-    Compares two JSON values for equality according to the following rules:
-    - Two JSON values are equal if (1) they are from the same type and (2)
-      their stored values are the same.
+    Compares whether one JSON value @a lhs is less than another JSON value @a
+    rhs according to the following rules:
+    - If @a lhs and @a rhs have the same type, the values are compared using
+      the default `<` operator.
     - Integer and floating-point numbers are automatically converted before
-      comparison. Floating-point numbers are compared indirectly: two
-      floating-point numbers `f1` and `f2` are considered equal if neither
-      `f1 > f2` nor `f2 > f1` holds.
-    - Two JSON null values are equal.
+      comparison
+    - In case @a lhs and @a rhs have different types, the values are ignored
+      and the order of the types is considered, see
+      @ref operator<(const value_t, const value_t).
 
     @param[in] lhs  first JSON value to consider
     @param[in] rhs  second JSON value to consider
-    @return whether the values @a lhs and @a rhs are equal
+    @return whether @a lhs is less than @a rhs
 
     @complexity Linear.
 
     @liveexample{The example demonstrates comparing several JSON
-    types.,operator__equal}
+    types.,operator__less}
 
     @since version 1.0.0
     */
-    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
+    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
     {
         const auto lhs_type = lhs.type();
         const auto rhs_type = rhs.type();
@@ -5561,35 +6367,35 @@ class basic_json
             {
                 case value_t::array:
                 {
-                    return *lhs.m_value.array == *rhs.m_value.array;
+                    return *lhs.m_value.array < *rhs.m_value.array;
                 }
                 case value_t::object:
                 {
-                    return *lhs.m_value.object == *rhs.m_value.object;
+                    return *lhs.m_value.object < *rhs.m_value.object;
                 }
                 case value_t::null:
                 {
-                    return true;
+                    return false;
                 }
                 case value_t::string:
                 {
-                    return *lhs.m_value.string == *rhs.m_value.string;
+                    return *lhs.m_value.string < *rhs.m_value.string;
                 }
                 case value_t::boolean:
                 {
-                    return lhs.m_value.boolean == rhs.m_value.boolean;
+                    return lhs.m_value.boolean < rhs.m_value.boolean;
                 }
                 case value_t::number_integer:
                 {
-                    return lhs.m_value.number_integer == rhs.m_value.number_integer;
+                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
                 }
                 case value_t::number_unsigned:
                 {
-                    return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned;
+                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
                 }
                 case value_t::number_float:
                 {
-                    return lhs.m_value.number_float == rhs.m_value.number_float;
+                    return lhs.m_value.number_float < rhs.m_value.number_float;
                 }
                 default:
                 {
@@ -5599,295 +6405,786 @@ class basic_json
         }
         else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
         {
-            return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float;
+            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
         }
         else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
         {
-            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
+            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
         }
         else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
         {
-            return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float;
+            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
         }
         else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
         {
-            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned);
+            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
         }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
         {
-            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer;
+            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
         }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
         {
-            return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned);
+            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
         }
 
-        return false;
+        // We only reach this line if we cannot compare values. In that case,
+        // we compare types. Note we have to call the operator explicitly,
+        // because MSVC has problems otherwise.
+        return operator<(lhs_type, rhs_type);
     }
 
     /*!
-    @brief comparison: equal
+    @brief comparison: less than
+    @copydoc operator<(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator<(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs < basic_json(rhs));
+    }
+
+    /*!
+    @brief comparison: less than
+    @copydoc operator<(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator<(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) < rhs);
+    }
 
-    The functions compares the given JSON value against a null pointer. As the
-    null pointer can be used to initialize a JSON value to null, a comparison
-    of JSON value @a v with a null pointer should be equivalent to call
-    `v.is_null()`.
+    /*!
+    @brief comparison: less than or equal
 
-    @param[in] v  JSON value to consider
-    @return whether @a v is null
+    Compares whether one JSON value @a lhs is less than or equal to another
+    JSON value by calculating `not (rhs < lhs)`.
 
-    @complexity Constant.
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is less than or equal to @a rhs
+
+    @complexity Linear.
 
-    @liveexample{The example compares several JSON types to the null pointer.
-    ,operator__equal__nullptr_t}
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__greater}
 
     @since version 1.0.0
     */
-    friend bool operator==(const_reference v, std::nullptr_t) noexcept
+    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
     {
-        return v.is_null();
+        return not (rhs < lhs);
     }
 
     /*!
-    @brief comparison: equal
-    @copydoc operator==(const_reference, std::nullptr_t)
+    @brief comparison: less than or equal
+    @copydoc operator<=(const_reference, const_reference)
     */
-    friend bool operator==(std::nullptr_t, const_reference v) noexcept
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator<=(const_reference lhs, const ScalarType rhs) noexcept
     {
-        return v.is_null();
+        return (lhs <= basic_json(rhs));
     }
 
     /*!
-    @brief comparison: not equal
+    @brief comparison: less than or equal
+    @copydoc operator<=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator<=(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) <= rhs);
+    }
 
-    Compares two JSON values for inequality by calculating `not (lhs == rhs)`.
+    /*!
+    @brief comparison: greater than
+
+    Compares whether one JSON value @a lhs is greater than another
+    JSON value by calculating `not (lhs <= rhs)`.
 
     @param[in] lhs  first JSON value to consider
     @param[in] rhs  second JSON value to consider
-    @return whether the values @a lhs and @a rhs are not equal
+    @return whether @a lhs is greater than to @a rhs
 
     @complexity Linear.
 
     @liveexample{The example demonstrates comparing several JSON
-    types.,operator__notequal}
+    types.,operator__lessequal}
 
     @since version 1.0.0
     */
-    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
+    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
     {
-        return not (lhs == rhs);
+        return not (lhs <= rhs);
     }
 
     /*!
-    @brief comparison: not equal
+    @brief comparison: greater than
+    @copydoc operator>(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator>(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs > basic_json(rhs));
+    }
+
+    /*!
+    @brief comparison: greater than
+    @copydoc operator>(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator>(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) > rhs);
+    }
 
-    The functions compares the given JSON value against a null pointer. As the
-    null pointer can be used to initialize a JSON value to null, a comparison
-    of JSON value @a v with a null pointer should be equivalent to call
-    `not v.is_null()`.
+    /*!
+    @brief comparison: greater than or equal
 
-    @param[in] v  JSON value to consider
-    @return whether @a v is not null
+    Compares whether one JSON value @a lhs is greater than or equal to another
+    JSON value by calculating `not (lhs < rhs)`.
 
-    @complexity Constant.
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is greater than or equal to @a rhs
+
+    @complexity Linear.
 
-    @liveexample{The example compares several JSON types to the null pointer.
-    ,operator__notequal__nullptr_t}
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__greaterequal}
 
     @since version 1.0.0
     */
-    friend bool operator!=(const_reference v, std::nullptr_t) noexcept
+    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
     {
-        return not v.is_null();
+        return not (lhs < rhs);
     }
 
     /*!
-    @brief comparison: not equal
-    @copydoc operator!=(const_reference, std::nullptr_t)
+    @brief comparison: greater than or equal
+    @copydoc operator>=(const_reference, const_reference)
     */
-    friend bool operator!=(std::nullptr_t, const_reference v) noexcept
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator>=(const_reference lhs, const ScalarType rhs) noexcept
     {
-        return not v.is_null();
+        return (lhs >= basic_json(rhs));
     }
 
     /*!
-    @brief comparison: less than
+    @brief comparison: greater than or equal
+    @copydoc operator>=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator>=(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) >= rhs);
+    }
 
-    Compares whether one JSON value @a lhs is less than another JSON value @a
-    rhs according to the following rules:
-    - If @a lhs and @a rhs have the same type, the values are compared using
-      the default `<` operator.
-    - Integer and floating-point numbers are automatically converted before
-      comparison
-    - In case @a lhs and @a rhs have different types, the values are ignored
-      and the order of the types is considered, see
-      @ref operator<(const value_t, const value_t).
+    /// @}
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is less than @a rhs
 
-    @complexity Linear.
+    ///////////////////
+    // serialization //
+    ///////////////////
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__less}
+    /// @name serialization
+    /// @{
 
-    @since version 1.0.0
+  private:
+    /*!
+    @brief wrapper around the serialization functions
     */
-    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
+    class serializer
     {
-        const auto lhs_type = lhs.type();
-        const auto rhs_type = rhs.type();
+      private:
+        serializer(const serializer&) = delete;
+        serializer& operator=(const serializer&) = delete;
 
-        if (lhs_type == rhs_type)
+      public:
+        /*!
+        @param[in] s  output stream to serialize to
+        */
+        serializer(std::ostream& s)
+            : o(s), loc(std::localeconv()),
+              thousands_sep(!loc->thousands_sep ? '\0' : loc->thousands_sep[0]),
+              decimal_point(!loc->decimal_point ? '\0' : loc->decimal_point[0])
+        {}
+
+        /*!
+        @brief internal implementation of the serialization function
+
+        This function is called by the public member function dump and
+        organizes the serialization internally. The indentation level is
+        propagated as additional parameter. In case of arrays and objects, the
+        function is called recursively.
+
+        - strings and object keys are escaped using `escape_string()`
+        - integer numbers are converted implicitly via `operator<<`
+        - floating-point numbers are converted to a string using `"%g"` format
+
+        @param[in] val             value to serialize
+        @param[in] pretty_print    whether the output shall be pretty-printed
+        @param[in] indent_step     the indent level
+        @param[in] current_indent  the current indent level (only used internally)
+        */
+        void dump(const basic_json& val,
+                  const bool pretty_print,
+                  const unsigned int indent_step,
+                  const unsigned int current_indent = 0)
         {
-            switch (lhs_type)
+            switch (val.m_type)
             {
-                case value_t::array:
-                {
-                    return *lhs.m_value.array < *rhs.m_value.array;
-                }
                 case value_t::object:
                 {
-                    return *lhs.m_value.object < *rhs.m_value.object;
+                    if (val.m_value.object->empty())
+                    {
+                        o.write("{}", 2);
+                        return;
+                    }
+
+                    if (pretty_print)
+                    {
+                        o.write("{\n", 2);
+
+                        // variable to hold indentation for recursive calls
+                        const auto new_indent = current_indent + indent_step;
+                        if (indent_string.size() < new_indent)
+                        {
+                            indent_string.resize(new_indent, ' ');
+                        }
+
+                        // first n-1 elements
+                        auto i = val.m_value.object->cbegin();
+                        for (size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
+                        {
+                            o.write(indent_string.c_str(), static_cast<std::streamsize>(new_indent));
+                            o.put('\"');
+                            dump_escaped(i->first);
+                            o.write("\": ", 3);
+                            dump(i->second, true, indent_step, new_indent);
+                            o.write(",\n", 2);
+                        }
+
+                        // last element
+                        assert(i != val.m_value.object->cend());
+                        o.write(indent_string.c_str(), static_cast<std::streamsize>(new_indent));
+                        o.put('\"');
+                        dump_escaped(i->first);
+                        o.write("\": ", 3);
+                        dump(i->second, true, indent_step, new_indent);
+
+                        o.put('\n');
+                        o.write(indent_string.c_str(), static_cast<std::streamsize>(current_indent));
+                        o.put('}');
+                    }
+                    else
+                    {
+                        o.put('{');
+
+                        // first n-1 elements
+                        auto i = val.m_value.object->cbegin();
+                        for (size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
+                        {
+                            o.put('\"');
+                            dump_escaped(i->first);
+                            o.write("\":", 2);
+                            dump(i->second, false, indent_step, current_indent);
+                            o.put(',');
+                        }
+
+                        // last element
+                        assert(i != val.m_value.object->cend());
+                        o.put('\"');
+                        dump_escaped(i->first);
+                        o.write("\":", 2);
+                        dump(i->second, false, indent_step, current_indent);
+
+                        o.put('}');
+                    }
+
+                    return;
                 }
-                case value_t::null:
+
+                case value_t::array:
                 {
-                    return false;
+                    if (val.m_value.array->empty())
+                    {
+                        o.write("[]", 2);
+                        return;
+                    }
+
+                    if (pretty_print)
+                    {
+                        o.write("[\n", 2);
+
+                        // variable to hold indentation for recursive calls
+                        const auto new_indent = current_indent + indent_step;
+                        if (indent_string.size() < new_indent)
+                        {
+                            indent_string.resize(new_indent, ' ');
+                        }
+
+                        // first n-1 elements
+                        for (auto i = val.m_value.array->cbegin(); i != val.m_value.array->cend() - 1; ++i)
+                        {
+                            o.write(indent_string.c_str(), static_cast<std::streamsize>(new_indent));
+                            dump(*i, true, indent_step, new_indent);
+                            o.write(",\n", 2);
+                        }
+
+                        // last element
+                        assert(not val.m_value.array->empty());
+                        o.write(indent_string.c_str(), static_cast<std::streamsize>(new_indent));
+                        dump(val.m_value.array->back(), true, indent_step, new_indent);
+
+                        o.put('\n');
+                        o.write(indent_string.c_str(), static_cast<std::streamsize>(current_indent));
+                        o.put(']');
+                    }
+                    else
+                    {
+                        o.put('[');
+
+                        // first n-1 elements
+                        for (auto i = val.m_value.array->cbegin(); i != val.m_value.array->cend() - 1; ++i)
+                        {
+                            dump(*i, false, indent_step, current_indent);
+                            o.put(',');
+                        }
+
+                        // last element
+                        assert(not val.m_value.array->empty());
+                        dump(val.m_value.array->back(), false, indent_step, current_indent);
+
+                        o.put(']');
+                    }
+
+                    return;
                 }
+
                 case value_t::string:
                 {
-                    return *lhs.m_value.string < *rhs.m_value.string;
+                    o.put('\"');
+                    dump_escaped(*val.m_value.string);
+                    o.put('\"');
+                    return;
                 }
+
                 case value_t::boolean:
                 {
-                    return lhs.m_value.boolean < rhs.m_value.boolean;
+                    if (val.m_value.boolean)
+                    {
+                        o.write("true", 4);
+                    }
+                    else
+                    {
+                        o.write("false", 5);
+                    }
+                    return;
                 }
+
                 case value_t::number_integer:
                 {
-                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
+                    dump_integer(val.m_value.number_integer);
+                    return;
                 }
+
                 case value_t::number_unsigned:
                 {
-                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
+                    dump_integer(val.m_value.number_unsigned);
+                    return;
                 }
+
                 case value_t::number_float:
                 {
-                    return lhs.m_value.number_float < rhs.m_value.number_float;
+                    dump_float(val.m_value.number_float);
+                    return;
                 }
-                default:
+
+                case value_t::discarded:
                 {
-                    return false;
+                    o.write("<discarded>", 11);
+                    return;
+                }
+
+                case value_t::null:
+                {
+                    o.write("null", 4);
+                    return;
                 }
             }
         }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
-        {
-            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
+
+      private:
+        /*!
+        @brief calculates the extra space to escape a JSON string
+
+        @param[in] s  the string to escape
+        @return the number of characters required to escape string @a s
+
+        @complexity Linear in the length of string @a s.
+        */
+        static std::size_t extra_space(const string_t& s) noexcept
+        {
+            return std::accumulate(s.begin(), s.end(), size_t{},
+                                   [](size_t res, typename string_t::value_type c)
+            {
+                switch (c)
+                {
+                    case '"':
+                    case '\\':
+                    case '\b':
+                    case '\f':
+                    case '\n':
+                    case '\r':
+                    case '\t':
+                    {
+                        // from c (1 byte) to \x (2 bytes)
+                        return res + 1;
+                    }
+
+                    case 0x00:
+                    case 0x01:
+                    case 0x02:
+                    case 0x03:
+                    case 0x04:
+                    case 0x05:
+                    case 0x06:
+                    case 0x07:
+                    case 0x0b:
+                    case 0x0e:
+                    case 0x0f:
+                    case 0x10:
+                    case 0x11:
+                    case 0x12:
+                    case 0x13:
+                    case 0x14:
+                    case 0x15:
+                    case 0x16:
+                    case 0x17:
+                    case 0x18:
+                    case 0x19:
+                    case 0x1a:
+                    case 0x1b:
+                    case 0x1c:
+                    case 0x1d:
+                    case 0x1e:
+                    case 0x1f:
+                    {
+                        // from c (1 byte) to \uxxxx (6 bytes)
+                        return res + 5;
+                    }
+
+                    default:
+                    {
+                        return res;
+                    }
+                }
+            });
         }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+
+        /*!
+        @brief dump escaped string
+
+        Escape a string by replacing certain special characters by a sequence
+        of an escape character (backslash) and another character and other
+        control characters by a sequence of "\u" followed by a four-digit hex
+        representation. The escaped string is written to output stream @a o.
+
+        @param[in] s  the string to escape
+
+        @complexity Linear in the length of string @a s.
+        */
+        void dump_escaped(const string_t& s) const
         {
-            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
+            const auto space = extra_space(s);
+            if (space == 0)
+            {
+                o.write(s.c_str(), static_cast<std::streamsize>(s.size()));
+                return;
+            }
+
+            // create a result string of necessary size
+            string_t result(s.size() + space, '\\');
+            std::size_t pos = 0;
+
+            for (const auto& c : s)
+            {
+                switch (c)
+                {
+                    // quotation mark (0x22)
+                    case '"':
+                    {
+                        result[pos + 1] = '"';
+                        pos += 2;
+                        break;
+                    }
+
+                    // reverse solidus (0x5c)
+                    case '\\':
+                    {
+                        // nothing to change
+                        pos += 2;
+                        break;
+                    }
+
+                    // backspace (0x08)
+                    case '\b':
+                    {
+                        result[pos + 1] = 'b';
+                        pos += 2;
+                        break;
+                    }
+
+                    // formfeed (0x0c)
+                    case '\f':
+                    {
+                        result[pos + 1] = 'f';
+                        pos += 2;
+                        break;
+                    }
+
+                    // newline (0x0a)
+                    case '\n':
+                    {
+                        result[pos + 1] = 'n';
+                        pos += 2;
+                        break;
+                    }
+
+                    // carriage return (0x0d)
+                    case '\r':
+                    {
+                        result[pos + 1] = 'r';
+                        pos += 2;
+                        break;
+                    }
+
+                    // horizontal tab (0x09)
+                    case '\t':
+                    {
+                        result[pos + 1] = 't';
+                        pos += 2;
+                        break;
+                    }
+
+                    case 0x00:
+                    case 0x01:
+                    case 0x02:
+                    case 0x03:
+                    case 0x04:
+                    case 0x05:
+                    case 0x06:
+                    case 0x07:
+                    case 0x0b:
+                    case 0x0e:
+                    case 0x0f:
+                    case 0x10:
+                    case 0x11:
+                    case 0x12:
+                    case 0x13:
+                    case 0x14:
+                    case 0x15:
+                    case 0x16:
+                    case 0x17:
+                    case 0x18:
+                    case 0x19:
+                    case 0x1a:
+                    case 0x1b:
+                    case 0x1c:
+                    case 0x1d:
+                    case 0x1e:
+                    case 0x1f:
+                    {
+                        // convert a number 0..15 to its hex representation
+                        // (0..f)
+                        static const char hexify[16] =
+                        {
+                            '0', '1', '2', '3', '4', '5', '6', '7',
+                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
+                        };
+
+                        // print character c as \uxxxx
+                        for (const char m :
+                    { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f]
+                        })
+                        {
+                            result[++pos] = m;
+                        }
+
+                        ++pos;
+                        break;
+                    }
+
+                    default:
+                    {
+                        // all other characters are added as-is
+                        result[pos++] = c;
+                        break;
+                    }
+                }
+            }
+
+            assert(pos == s.size() + space);
+            o.write(result.c_str(), static_cast<std::streamsize>(result.size()));
         }
 
-        // We only reach this line if we cannot compare values. In that case,
-        // we compare types. Note we have to call the operator explicitly,
-        // because MSVC has problems otherwise.
-        return operator<(lhs_type, rhs_type);
-    }
+        /*!
+        @brief dump an integer
 
-    /*!
-    @brief comparison: less than or equal
+        Dump a given integer to output stream @a o. Works internally with
+        @a number_buffer.
 
-    Compares whether one JSON value @a lhs is less than or equal to another
-    JSON value by calculating `not (rhs < lhs)`.
+        @param[in] x  integer number (signed or unsigned) to dump
+        @tparam NumberType either @a number_integer_t or @a number_unsigned_t
+        */
+        template<typename NumberType, detail::enable_if_t <
+                     std::is_same<NumberType, number_unsigned_t>::value or
+                     std::is_same<NumberType, number_integer_t>::value, int> = 0>
+        void dump_integer(NumberType x)
+        {
+            // special case for "0"
+            if (x == 0)
+            {
+                o.put('0');
+                return;
+            }
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is less than or equal to @a rhs
+            const bool is_negative = x < 0;
+            size_t i = 0;
 
-    @complexity Linear.
+            // spare 1 byte for '\0'
+            while (x != 0 and i < number_buffer.size() - 1)
+            {
+                const auto digit = std::labs(static_cast<long>(x % 10));
+                number_buffer[i++] = static_cast<char>('0' + digit);
+                x /= 10;
+            }
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__greater}
+            // make sure the number has been processed completely
+            assert(x == 0);
 
-    @since version 1.0.0
-    */
-    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (rhs < lhs);
-    }
+            if (is_negative)
+            {
+                // make sure there is capacity for the '-'
+                assert(i < number_buffer.size() - 2);
+                number_buffer[i++] = '-';
+            }
 
-    /*!
-    @brief comparison: greater than
+            std::reverse(number_buffer.begin(), number_buffer.begin() + i);
+            o.write(number_buffer.data(), static_cast<std::streamsize>(i));
+        }
 
-    Compares whether one JSON value @a lhs is greater than another
-    JSON value by calculating `not (lhs <= rhs)`.
+        /*!
+        @brief dump a floating-point number
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is greater than to @a rhs
+        Dump a given floating-point number to output stream @a o. Works
+        internally with @a number_buffer.
 
-    @complexity Linear.
+        @param[in] x  floating-point number to dump
+        */
+        void dump_float(number_float_t x)
+        {
+            // NaN / inf
+            if (not std::isfinite(x) or std::isnan(x))
+            {
+                o.write("null", 4);
+                return;
+            }
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__lessequal}
+            // special case for 0.0 and -0.0
+            if (x == 0)
+            {
+                if (std::signbit(x))
+                {
+                    o.write("-0.0", 4);
+                }
+                else
+                {
+                    o.write("0.0", 3);
+                }
+                return;
+            }
 
-    @since version 1.0.0
-    */
-    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs <= rhs);
-    }
+            // get number of digits for a text -> float -> text round-trip
+            static constexpr auto d = std::numeric_limits<number_float_t>::digits10;
 
-    /*!
-    @brief comparison: greater than or equal
+            // the actual conversion
+            std::ptrdiff_t len = snprintf(number_buffer.data(), number_buffer.size(),
+                                          "%.*g", d, x);
 
-    Compares whether one JSON value @a lhs is greater than or equal to another
-    JSON value by calculating `not (lhs < rhs)`.
+            // negative value indicates an error
+            assert(len > 0);
+            // check if buffer was large enough
+            assert(static_cast<size_t>(len) < number_buffer.size());
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is greater than or equal to @a rhs
+            // erase thousands separator
+            if (thousands_sep != '\0')
+            {
+                const auto end = std::remove(number_buffer.begin(),
+                                             number_buffer.begin() + len,
+                                             thousands_sep);
+                std::fill(end, number_buffer.end(), '\0');
+                assert((end - number_buffer.begin()) <= len);
+                len = (end - number_buffer.begin());
+            }
 
-    @complexity Linear.
+            // convert decimal point to '.'
+            if (decimal_point != '\0' and decimal_point != '.')
+            {
+                for (auto& c : number_buffer)
+                {
+                    if (c == decimal_point)
+                    {
+                        c = '.';
+                        break;
+                    }
+                }
+            }
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__greaterequal}
+            o.write(number_buffer.data(), static_cast<std::streamsize>(len));
 
-    @since version 1.0.0
-    */
-    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs < rhs);
-    }
+            // determine if need to append ".0"
+            const bool value_is_int_like = std::none_of(number_buffer.begin(),
+                                           number_buffer.begin() + len + 1,
+                                           [](char c)
+            {
+                return c == '.' or c == 'e';
+            });
 
-    /// @}
+            if (value_is_int_like)
+            {
+                o.write(".0", 2);
+            }
+        }
 
+      private:
+        /// the output of the serializer
+        std::ostream& o;
 
-    ///////////////////
-    // serialization //
-    ///////////////////
+        /// a (hopefully) large enough character buffer
+        std::array<char, 64> number_buffer{{}};
 
-    /// @name serialization
-    /// @{
+        /// the locale
+        const std::lconv* loc = nullptr;
+        /// the locale's thousand separator character
+        const char thousands_sep = '\0';
+        /// the locale's decimal point character
+        const char decimal_point = '\0';
+
+        /// the indentation string
+        string_t indent_string = string_t(512, ' ');
+    };
 
+  public:
     /*!
     @brief serialize to stream
 
@@ -5898,10 +7195,6 @@ class basic_json
     `std::setw(4)` on @a o sets the indentation level to `4` and the
     serialization result is the same as calling `dump(4)`.
 
-    @note During serializaion, the locale and the precision of the output
-    stream @a o are changed. The original values are restored when the
-    function returns.
-
     @param[in,out] o  stream to serialize to
     @param[in] j  JSON value to serialize
 
@@ -5923,29 +7216,20 @@ class basic_json
         // reset width to 0 for subsequent calls to this stream
         o.width(0);
 
-        // fix locale problems
-        const auto old_locale = o.imbue(std::locale::classic());
-        // set precision
-
-        // 6, 15 or 16 digits of precision allows round-trip IEEE 754
-        // string->float->string, string->double->string or string->long
-        // double->string; to be safe, we read this value from
-        // std::numeric_limits<number_float_t>::digits10
-        const auto old_precision = o.precision(std::numeric_limits<double>::digits10);
-
         // do the actual serialization
-        j.dump(o, pretty_print, static_cast<unsigned int>(indentation));
-
-        // reset locale and precision
-        o.imbue(old_locale);
-        o.precision(old_precision);
+        serializer s(o);
+        s.dump(j, pretty_print, static_cast<unsigned int>(indentation));
         return o;
     }
 
     /*!
     @brief serialize to stream
-    @copydoc operator<<(std::ostream&, const basic_json&)
+    @deprecated This stream operator is deprecated and will be removed in a
+                future version of the library. Please use
+                @ref std::ostream& operator<<(std::ostream&, const basic_json&)
+                instead; that is, replace calls like `j >> o;` with `o << j;`.
     */
+    JSON_DEPRECATED
     friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
     {
         return o << j;
@@ -5977,6 +7261,11 @@ class basic_json
 
     @return result of the deserialization
 
+    @throw parse_error.101 if a parse error occurs; example: `""unexpected end
+    of input; expected string literal""`
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
+
     @complexity Linear in the length of the input. The parser is a predictive
     LL(1) parser. The complexity can be higher if the parser callback function
     @a cb has a super-linear complexity.
@@ -6007,6 +7296,10 @@ class basic_json
 
     @return result of the deserialization
 
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
+
     @complexity Linear in the length of the input. The parser is a predictive
     LL(1) parser. The complexity can be higher if the parser callback function
     @a cb has a super-linear complexity.
@@ -6043,6 +7336,11 @@ class basic_json
 
     @return result of the deserialization
 
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
+    @throw parse_error.111 if input stream is in a bad state
+
     @complexity Linear in the length of the input. The parser is a predictive
     LL(1) parser. The complexity can be higher if the parser callback function
     @a cb has a super-linear complexity.
@@ -6102,6 +7400,10 @@ class basic_json
 
     @return result of the deserialization
 
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
+
     @complexity Linear in the length of the input. The parser is a predictive
     LL(1) parser. The complexity can be higher if the parser callback function
     @a cb has a super-linear complexity.
@@ -6122,7 +7424,7 @@ class basic_json
     {
         // assertion to check that the iterator range is indeed contiguous,
         // see http://stackoverflow.com/a/35008842/266378 for more discussion
-        assert(std::accumulate(first, last, std::make_pair<bool, int>(true, 0),
+        assert(std::accumulate(first, last, std::pair<bool, int>(true, 0),
                                [&first](std::pair<bool, int> res, decltype(*first) val)
         {
             res.first &= (val == *(std::next(std::addressof(*first), res.second++)));
@@ -6172,6 +7474,10 @@ class basic_json
 
     @return result of the deserialization
 
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
+
     @complexity Linear in the length of the input. The parser is a predictive
     LL(1) parser. The complexity can be higher if the parser callback function
     @a cb has a super-linear complexity.
@@ -6192,8 +7498,22 @@ class basic_json
     static basic_json parse(const ContiguousContainer& c,
                             const parser_callback_t cb = nullptr)
     {
-        // delegate the call to the iterator-range parse overload
-        return parse(std::begin(c), std::end(c), cb);
+        // delegate the call to the iterator-range parse overload
+        return parse(std::begin(c), std::end(c), cb);
+    }
+
+    /*!
+    @brief deserialize from stream
+    @deprecated This stream operator is deprecated and will be removed in a
+                future version of the library. Please use
+                @ref std::istream& operator>>(std::istream&, basic_json&)
+                instead; that is, replace calls like `j << i;` with `i >> j;`.
+    */
+    JSON_DEPRECATED
+    friend std::istream& operator<<(basic_json& j, std::istream& i)
+    {
+        j = parser(i).parse();
+        return i;
     }
 
     /*!
@@ -6204,7 +7524,10 @@ class basic_json
     @param[in,out] i  input stream to read a serialized JSON value from
     @param[in,out] j  JSON value to write the deserialized input to
 
-    @throw std::invalid_argument in case of parse errors
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
+    @throw parse_error.111 if input stream is in a bad state
 
     @complexity Linear in the length of the input. The parser is a predictive
     LL(1) parser.
@@ -6219,16 +7542,6 @@ class basic_json
 
     @since version 1.0.0
     */
-    friend std::istream& operator<<(basic_json& j, std::istream& i)
-    {
-        j = parser(i).parse();
-        return i;
-    }
-
-    /*!
-    @brief deserialize from stream
-    @copydoc operator<<(basic_json&, std::istream&)
-    */
     friend std::istream& operator>>(std::istream& i, basic_json& j)
     {
         j = parser(i).parse();
@@ -6245,6 +7558,11 @@ class basic_json
     /// @{
 
   private:
+    /*!
+    @note Some code in the switch cases has been copied, because otherwise
+          copilers would complain about implicit fallthrough and there is no
+          portable attribute to mute such warnings.
+    */
     template<typename T>
     static void add_to_vector(std::vector<uint8_t>& vec, size_t bytes, const T number)
     {
@@ -6254,24 +7572,31 @@ class basic_json
         {
             case 8:
             {
-                vec.push_back(static_cast<uint8_t>((number >> 070) & 0xff));
-                vec.push_back(static_cast<uint8_t>((number >> 060) & 0xff));
-                vec.push_back(static_cast<uint8_t>((number >> 050) & 0xff));
-                vec.push_back(static_cast<uint8_t>((number >> 040) & 0xff));
-                // intentional fall-through
+                vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 070) & 0xff));
+                vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 060) & 0xff));
+                vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 050) & 0xff));
+                vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 040) & 0xff));
+                vec.push_back(static_cast<uint8_t>((number >> 030) & 0xff));
+                vec.push_back(static_cast<uint8_t>((number >> 020) & 0xff));
+                vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff));
+                vec.push_back(static_cast<uint8_t>(number & 0xff));
+                break;
             }
 
             case 4:
             {
                 vec.push_back(static_cast<uint8_t>((number >> 030) & 0xff));
                 vec.push_back(static_cast<uint8_t>((number >> 020) & 0xff));
-                // intentional fall-through
+                vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff));
+                vec.push_back(static_cast<uint8_t>(number & 0xff));
+                break;
             }
 
             case 2:
             {
                 vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff));
-                // intentional fall-through
+                vec.push_back(static_cast<uint8_t>(number & 0xff));
+                break;
             }
 
             case 1:
@@ -6296,7 +7621,7 @@ class basic_json
 
     @tparam T the integral return type
 
-    @throw std::out_of_range if there are less than sizeof(T)+1 bytes in the
+    @throw parse_error.110 if there are less than sizeof(T)+1 bytes in the
            vector @a vec to read
 
     In the for loop, the bytes from the vector are copied in reverse order into
@@ -6321,13 +7646,11 @@ class basic_json
     template<typename T>
     static T get_from_vector(const std::vector<uint8_t>& vec, const size_t current_index)
     {
-        if (current_index + sizeof(T) + 1 > vec.size())
-        {
-            throw std::out_of_range("cannot read " + std::to_string(sizeof(T)) + " bytes from vector");
-        }
+        // check if we can read sizeof(T) bytes starting the next index
+        check_length(vec.size(), sizeof(T), current_index + 1);
 
         T result;
-        uint8_t* ptr = reinterpret_cast<uint8_t*>(&result);
+        auto* ptr = reinterpret_cast<uint8_t*>(&result);
         for (size_t i = 0; i < sizeof(T); ++i)
         {
             *ptr++ = vec[current_index + sizeof(T) - i];
@@ -6368,32 +7691,33 @@ class basic_json
                 if (j.m_value.number_integer >= 0)
                 {
                     // MessagePack does not differentiate between positive
-                    // signed integers and unsigned integers. Therefore, we used
-                    // the code from the value_t::number_unsigned case here.
+                    // signed integers and unsigned integers. Therefore, we
+                    // used the code from the value_t::number_unsigned case
+                    // here.
                     if (j.m_value.number_unsigned < 128)
                     {
                         // positive fixnum
                         add_to_vector(v, 1, j.m_value.number_unsigned);
                     }
-                    else if (j.m_value.number_unsigned <= UINT8_MAX)
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
                     {
                         // uint 8
                         v.push_back(0xcc);
                         add_to_vector(v, 1, j.m_value.number_unsigned);
                     }
-                    else if (j.m_value.number_unsigned <= UINT16_MAX)
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
                     {
                         // uint 16
                         v.push_back(0xcd);
                         add_to_vector(v, 2, j.m_value.number_unsigned);
                     }
-                    else if (j.m_value.number_unsigned <= UINT32_MAX)
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
                     {
                         // uint 32
                         v.push_back(0xce);
                         add_to_vector(v, 4, j.m_value.number_unsigned);
                     }
-                    else if (j.m_value.number_unsigned <= UINT64_MAX)
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)())
                     {
                         // uint 64
                         v.push_back(0xcf);
@@ -6407,25 +7731,25 @@ class basic_json
                         // negative fixnum
                         add_to_vector(v, 1, j.m_value.number_integer);
                     }
-                    else if (j.m_value.number_integer >= INT8_MIN and j.m_value.number_integer <= INT8_MAX)
+                    else if (j.m_value.number_integer >= (std::numeric_limits<int8_t>::min)() and j.m_value.number_integer <= (std::numeric_limits<int8_t>::max)())
                     {
                         // int 8
                         v.push_back(0xd0);
                         add_to_vector(v, 1, j.m_value.number_integer);
                     }
-                    else if (j.m_value.number_integer >= INT16_MIN and j.m_value.number_integer <= INT16_MAX)
+                    else if (j.m_value.number_integer >= (std::numeric_limits<int16_t>::min)() and j.m_value.number_integer <= (std::numeric_limits<int16_t>::max)())
                     {
                         // int 16
                         v.push_back(0xd1);
                         add_to_vector(v, 2, j.m_value.number_integer);
                     }
-                    else if (j.m_value.number_integer >= INT32_MIN and j.m_value.number_integer <= INT32_MAX)
+                    else if (j.m_value.number_integer >= (std::numeric_limits<int32_t>::min)() and j.m_value.number_integer <= (std::numeric_limits<int32_t>::max)())
                     {
                         // int 32
                         v.push_back(0xd2);
                         add_to_vector(v, 4, j.m_value.number_integer);
                     }
-                    else if (j.m_value.number_integer >= INT64_MIN and j.m_value.number_integer <= INT64_MAX)
+                    else if (j.m_value.number_integer >= (std::numeric_limits<int64_t>::min)() and j.m_value.number_integer <= (std::numeric_limits<int64_t>::max)())
                     {
                         // int 64
                         v.push_back(0xd3);
@@ -6442,25 +7766,25 @@ class basic_json
                     // positive fixnum
                     add_to_vector(v, 1, j.m_value.number_unsigned);
                 }
-                else if (j.m_value.number_unsigned <= UINT8_MAX)
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
                 {
                     // uint 8
                     v.push_back(0xcc);
                     add_to_vector(v, 1, j.m_value.number_unsigned);
                 }
-                else if (j.m_value.number_unsigned <= UINT16_MAX)
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
                 {
                     // uint 16
                     v.push_back(0xcd);
                     add_to_vector(v, 2, j.m_value.number_unsigned);
                 }
-                else if (j.m_value.number_unsigned <= UINT32_MAX)
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
                 {
                     // uint 32
                     v.push_back(0xce);
                     add_to_vector(v, 4, j.m_value.number_unsigned);
                 }
-                else if (j.m_value.number_unsigned <= UINT64_MAX)
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)())
                 {
                     // uint 64
                     v.push_back(0xcf);
@@ -6473,7 +7797,7 @@ class basic_json
             {
                 // float 64
                 v.push_back(0xcb);
-                const uint8_t* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float));
+                const auto* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float));
                 for (size_t i = 0; i < 8; ++i)
                 {
                     v.push_back(helper[7 - i]);
@@ -6617,19 +7941,19 @@ class basic_json
                     {
                         add_to_vector(v, 1, j.m_value.number_integer);
                     }
-                    else if (j.m_value.number_integer <= UINT8_MAX)
+                    else if (j.m_value.number_integer <= (std::numeric_limits<uint8_t>::max)())
                     {
                         v.push_back(0x18);
                         // one-byte uint8_t
                         add_to_vector(v, 1, j.m_value.number_integer);
                     }
-                    else if (j.m_value.number_integer <= UINT16_MAX)
+                    else if (j.m_value.number_integer <= (std::numeric_limits<uint16_t>::max)())
                     {
                         v.push_back(0x19);
                         // two-byte uint16_t
                         add_to_vector(v, 2, j.m_value.number_integer);
                     }
-                    else if (j.m_value.number_integer <= UINT32_MAX)
+                    else if (j.m_value.number_integer <= (std::numeric_limits<uint32_t>::max)())
                     {
                         v.push_back(0x1a);
                         // four-byte uint32_t
@@ -6644,26 +7968,26 @@ class basic_json
                 }
                 else
                 {
-                    // The conversions below encode the sign in the first byte,
-                    // and the value is converted to a positive number.
+                    // The conversions below encode the sign in the first
+                    // byte, and the value is converted to a positive number.
                     const auto positive_number = -1 - j.m_value.number_integer;
                     if (j.m_value.number_integer >= -24)
                     {
                         v.push_back(static_cast<uint8_t>(0x20 + positive_number));
                     }
-                    else if (positive_number <= UINT8_MAX)
+                    else if (positive_number <= (std::numeric_limits<uint8_t>::max)())
                     {
                         // int 8
                         v.push_back(0x38);
                         add_to_vector(v, 1, positive_number);
                     }
-                    else if (positive_number <= UINT16_MAX)
+                    else if (positive_number <= (std::numeric_limits<uint16_t>::max)())
                     {
                         // int 16
                         v.push_back(0x39);
                         add_to_vector(v, 2, positive_number);
                     }
-                    else if (positive_number <= UINT32_MAX)
+                    else if (positive_number <= (std::numeric_limits<uint32_t>::max)())
                     {
                         // int 32
                         v.push_back(0x3a);
@@ -6716,7 +8040,7 @@ class basic_json
             {
                 // Double-Precision Float
                 v.push_back(0xfb);
-                const uint8_t* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float));
+                const auto* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float));
                 for (size_t i = 0; i < 8; ++i)
                 {
                     v.push_back(helper[7 - i]);
@@ -6729,7 +8053,7 @@ class basic_json
                 const auto N = j.m_value.string->size();
                 if (N <= 0x17)
                 {
-                    v.push_back(0x60 + N);  // 1 byte for string + size
+                    v.push_back(static_cast<uint8_t>(0x60 + N));  // 1 byte for string + size
                 }
                 else if (N <= 0xff)
                 {
@@ -6765,7 +8089,7 @@ class basic_json
                 const auto N = j.m_value.array->size();
                 if (N <= 0x17)
                 {
-                    v.push_back(0x80 + N);  // 1 byte for array + size
+                    v.push_back(static_cast<uint8_t>(0x80 + N));  // 1 byte for array + size
                 }
                 else if (N <= 0xff)
                 {
@@ -6803,7 +8127,7 @@ class basic_json
                 const auto N = j.m_value.object->size();
                 if (N <= 0x17)
                 {
-                    v.push_back(0xa0 + N);  // 1 byte for object + size
+                    v.push_back(static_cast<uint8_t>(0xa0 + N));  // 1 byte for object + size
                 }
                 else if (N <= 0xff)
                 {
@@ -6850,12 +8174,12 @@ class basic_json
 
     To secure the access to the byte vector during CBOR/MessagePack
     deserialization, bytes are copied from the vector into buffers. This
-    function checks if the number of bytes to copy (@a len) does not exceed the
-    size @s size of the vector. Additionally, an @a offset is given from where
-    to start reading the bytes.
+    function checks if the number of bytes to copy (@a len) does not exceed
+    the size @s size of the vector. Additionally, an @a offset is given from
+    where to start reading the bytes.
 
-    This function checks whether reading the bytes is safe; that is, offset is a
-    valid index in the vector, offset+len
+    This function checks whether reading the bytes is safe; that is, offset is
+    a valid index in the vector, offset+len
 
     @param[in] size    size of the byte vector
     @param[in] len     number of bytes to read
@@ -6872,20 +8196,81 @@ class basic_json
         // simple case: requested length is greater than the vector's length
         if (len > size or offset > size)
         {
-            throw std::out_of_range("len out of range");
+            JSON_THROW(parse_error::create(110, offset + 1, "cannot read " + std::to_string(len) + " bytes from vector"));
         }
 
         // second case: adding offset would result in overflow
-        if ((size > (std::numeric_limits<size_t>::max() - offset)))
+        if ((size > ((std::numeric_limits<size_t>::max)() - offset)))
         {
-            throw std::out_of_range("len+offset out of range");
+            JSON_THROW(parse_error::create(110, offset + 1, "cannot read " + std::to_string(len) + " bytes from vector"));
         }
 
         // last case: reading past the end of the vector
         if (len + offset > size)
         {
-            throw std::out_of_range("len+offset out of range");
+            JSON_THROW(parse_error::create(110, offset + 1, "cannot read " + std::to_string(len) + " bytes from vector"));
+        }
+    }
+
+    /*!
+    @brief check if the next byte belongs to a string
+
+    While parsing a map, the keys must be strings. This function checks if the
+    current byte is one of the start bytes for a string in MessagePack:
+
+    - 0xa0 - 0xbf: fixstr
+    - 0xd9: str 8
+    - 0xda: str 16
+    - 0xdb: str 32
+
+    @param[in] v  MessagePack serialization
+    @param[in] idx  byte index in @a v to check for a string
+
+    @throw parse_error.113 if `v[idx]` does not belong to a string
+    */
+    static void msgpack_expect_string(const std::vector<uint8_t>& v, size_t idx)
+    {
+        check_length(v.size(), 1, idx);
+
+        const auto byte = v[idx];
+        if ((byte >= 0xa0 and byte <= 0xbf) or (byte >= 0xd9 and byte <= 0xdb))
+        {
+            return;
+        }
+
+        std::stringstream ss;
+        ss << std::hex << static_cast<int>(v[idx]);
+        JSON_THROW(parse_error::create(113, idx + 1, "expected a MessagePack string; last byte: 0x" + ss.str()));
+    }
+
+    /*!
+    @brief check if the next byte belongs to a string
+
+    While parsing a map, the keys must be strings. This function checks if the
+    current byte is one of the start bytes for a string in CBOR:
+
+    - 0x60 - 0x77: fixed length
+    - 0x78 - 0x7b: variable length
+    - 0x7f: indefinity length
+
+    @param[in] v  CBOR serialization
+    @param[in] idx  byte index in @a v to check for a string
+
+    @throw parse_error.113 if `v[idx]` does not belong to a string
+    */
+    static void cbor_expect_string(const std::vector<uint8_t>& v, size_t idx)
+    {
+        check_length(v.size(), 1, idx);
+
+        const auto byte = v[idx];
+        if ((byte >= 0x60 and byte <= 0x7b) or byte == 0x7f)
+        {
+            return;
         }
+
+        std::stringstream ss;
+        ss << std::hex << static_cast<int>(v[idx]);
+        JSON_THROW(parse_error::create(113, idx + 1, "expected a CBOR string; last byte: 0x" + ss.str()));
     }
 
     /*!
@@ -6896,32 +8281,34 @@ class basic_json
 
     @return deserialized JSON value
 
-    @throw std::invalid_argument if unsupported features from MessagePack were
+    @throw parse_error.110 if the given vector ends prematurely
+    @throw parse_error.112 if unsupported features from MessagePack were
     used in the given vector @a v or if the input is not valid MessagePack
-    @throw std::out_of_range if the given vector ends prematurely
+    @throw parse_error.113 if a string was expected as map key, but not found
 
     @sa https://github.com/msgpack/msgpack/blob/master/spec.md
     */
     static basic_json from_msgpack_internal(const std::vector<uint8_t>& v, size_t& idx)
     {
-        // make sure reading 1 byte is safe
-        check_length(v.size(), 1, idx);
-
         // store and increment index
         const size_t current_idx = idx++;
 
+        // make sure reading 1 byte is safe
+        check_length(v.size(), 1, current_idx);
+
         if (v[current_idx] <= 0xbf)
         {
             if (v[current_idx] <= 0x7f) // positive fixint
             {
                 return v[current_idx];
             }
-            else if (v[current_idx] <= 0x8f) // fixmap
+            if (v[current_idx] <= 0x8f) // fixmap
             {
                 basic_json result = value_t::object;
                 const size_t len = v[current_idx] & 0x0f;
                 for (size_t i = 0; i < len; ++i)
                 {
+                    msgpack_expect_string(v, idx);
                     std::string key = from_msgpack_internal(v, idx);
                     result[key] = from_msgpack_internal(v, idx);
                 }
@@ -6972,8 +8359,8 @@ class basic_json
                 case 0xca: // float 32
                 {
                     // copy bytes in reverse order into the double variable
-                    check_length(v.size(), sizeof(float), 1);
                     float res;
+                    check_length(v.size(), sizeof(float), current_idx + 1);
                     for (size_t byte = 0; byte < sizeof(float); ++byte)
                     {
                         reinterpret_cast<uint8_t*>(&res)[sizeof(float) - byte - 1] = v[current_idx + 1 + byte];
@@ -6985,8 +8372,8 @@ class basic_json
                 case 0xcb: // float 64
                 {
                     // copy bytes in reverse order into the double variable
-                    check_length(v.size(), sizeof(double), 1);
                     double res;
+                    check_length(v.size(), sizeof(double), current_idx + 1);
                     for (size_t byte = 0; byte < sizeof(double); ++byte)
                     {
                         reinterpret_cast<uint8_t*>(&res)[sizeof(double) - byte - 1] = v[current_idx + 1 + byte];
@@ -7101,6 +8488,7 @@ class basic_json
                     idx += 2; // skip 2 size bytes
                     for (size_t i = 0; i < len; ++i)
                     {
+                        msgpack_expect_string(v, idx);
                         std::string key = from_msgpack_internal(v, idx);
                         result[key] = from_msgpack_internal(v, idx);
                     }
@@ -7114,6 +8502,7 @@ class basic_json
                     idx += 4; // skip 4 size bytes
                     for (size_t i = 0; i < len; ++i)
                     {
+                        msgpack_expect_string(v, idx);
                         std::string key = from_msgpack_internal(v, idx);
                         result[key] = from_msgpack_internal(v, idx);
                     }
@@ -7122,7 +8511,9 @@ class basic_json
 
                 default:
                 {
-                    throw std::invalid_argument("error parsing a msgpack @ " + std::to_string(current_idx) + ": " + std::to_string(static_cast<int>(v[current_idx])));
+                    std::stringstream ss;
+                    ss << std::hex << static_cast<int>(v[current_idx]);
+                    JSON_THROW(parse_error::create(112, current_idx + 1, "error reading MessagePack; last byte: 0x" + ss.str()));
                 }
             }
         }
@@ -7136,9 +8527,10 @@ class basic_json
 
     @return deserialized JSON value
 
-    @throw std::invalid_argument if unsupported features from CBOR were used in
-    the given vector @a v or if the input is not valid CBOR
-    @throw std::out_of_range if the given vector ends prematurely
+    @throw parse_error.110 if the given vector ends prematurely
+    @throw parse_error.112 if unsupported features from CBOR were
+    used in the given vector @a v or if the input is not valid CBOR
+    @throw parse_error.113 if a string was expected as map key, but not found
 
     @sa https://tools.ietf.org/html/rfc7049
     */
@@ -7147,7 +8539,10 @@ class basic_json
         // store and increment index
         const size_t current_idx = idx++;
 
-        switch (v.at(current_idx))
+        // make sure reading 1 byte is safe
+        check_length(v.size(), 1, current_idx);
+
+        switch (v[current_idx])
         {
             // Integer 0x00..0x17 (0..23)
             case 0x00:
@@ -7328,7 +8723,7 @@ class basic_json
             case 0x7f: // UTF-8 string (indefinite length)
             {
                 std::string result;
-                while (v.at(idx) != 0xff)
+                while (static_cast<void>(check_length(v.size(), 1, idx)), v[idx] != 0xff)
                 {
                     string_t s = from_cbor_internal(v, idx);
                     result += s;
@@ -7424,7 +8819,7 @@ class basic_json
             case 0x9f: // array (indefinite length)
             {
                 basic_json result = value_t::array;
-                while (v.at(idx) != 0xff)
+                while (static_cast<void>(check_length(v.size(), 1, idx)), v[idx] != 0xff)
                 {
                     result.push_back(from_cbor_internal(v, idx));
                 }
@@ -7463,6 +8858,7 @@ class basic_json
                 const auto len = static_cast<size_t>(v[current_idx] - 0xa0);
                 for (size_t i = 0; i < len; ++i)
                 {
+                    cbor_expect_string(v, idx);
                     std::string key = from_cbor_internal(v, idx);
                     result[key] = from_cbor_internal(v, idx);
                 }
@@ -7476,6 +8872,7 @@ class basic_json
                 idx += 1; // skip 1 size byte
                 for (size_t i = 0; i < len; ++i)
                 {
+                    cbor_expect_string(v, idx);
                     std::string key = from_cbor_internal(v, idx);
                     result[key] = from_cbor_internal(v, idx);
                 }
@@ -7489,6 +8886,7 @@ class basic_json
                 idx += 2; // skip 2 size bytes
                 for (size_t i = 0; i < len; ++i)
                 {
+                    cbor_expect_string(v, idx);
                     std::string key = from_cbor_internal(v, idx);
                     result[key] = from_cbor_internal(v, idx);
                 }
@@ -7502,6 +8900,7 @@ class basic_json
                 idx += 4; // skip 4 size bytes
                 for (size_t i = 0; i < len; ++i)
                 {
+                    cbor_expect_string(v, idx);
                     std::string key = from_cbor_internal(v, idx);
                     result[key] = from_cbor_internal(v, idx);
                 }
@@ -7515,6 +8914,7 @@ class basic_json
                 idx += 8; // skip 8 size bytes
                 for (size_t i = 0; i < len; ++i)
                 {
+                    cbor_expect_string(v, idx);
                     std::string key = from_cbor_internal(v, idx);
                     result[key] = from_cbor_internal(v, idx);
                 }
@@ -7524,8 +8924,9 @@ class basic_json
             case 0xbf: // map (indefinite length)
             {
                 basic_json result = value_t::object;
-                while (v.at(idx) != 0xff)
+                while (static_cast<void>(check_length(v.size(), 1, idx)), v[idx] != 0xff)
                 {
+                    cbor_expect_string(v, idx);
                     std::string key = from_cbor_internal(v, idx);
                     result[key] = from_cbor_internal(v, idx);
                 }
@@ -7551,7 +8952,6 @@ class basic_json
 
             case 0xf9: // Half-Precision Float (two-byte IEEE 754)
             {
-                check_length(v.size(), 2, 1);
                 idx += 2; // skip two content bytes
 
                 // code from RFC 7049, Appendix D, Figure 3:
@@ -7561,6 +8961,7 @@ class basic_json
                 // include at least decoding support for them even without such
                 // support. An example of a small decoder for half-precision
                 // floating-point numbers in the C language is shown in Fig. 3.
+                check_length(v.size(), 2, current_idx + 1);
                 const int half = (v[current_idx + 1] << 8) + v[current_idx + 2];
                 const int exp = (half >> 10) & 0x1f;
                 const int mant = half & 0x3ff;
@@ -7575,16 +8976,18 @@ class basic_json
                 }
                 else
                 {
-                    val = mant == 0 ? INFINITY : NAN;
+                    val = mant == 0
+                          ? std::numeric_limits<double>::infinity()
+                          : std::numeric_limits<double>::quiet_NaN();
                 }
-                return half & 0x8000 ? -val : val;
+                return (half & 0x8000) != 0 ? -val : val;
             }
 
             case 0xfa: // Single-Precision Float (four-byte IEEE 754)
             {
                 // copy bytes in reverse order into the float variable
-                check_length(v.size(), sizeof(float), 1);
                 float res;
+                check_length(v.size(), sizeof(float), current_idx + 1);
                 for (size_t byte = 0; byte < sizeof(float); ++byte)
                 {
                     reinterpret_cast<uint8_t*>(&res)[sizeof(float) - byte - 1] = v[current_idx + 1 + byte];
@@ -7595,9 +8998,9 @@ class basic_json
 
             case 0xfb: // Double-Precision Float (eight-byte IEEE 754)
             {
-                check_length(v.size(), sizeof(double), 1);
                 // copy bytes in reverse order into the double variable
                 double res;
+                check_length(v.size(), sizeof(double), current_idx + 1);
                 for (size_t byte = 0; byte < sizeof(double); ++byte)
                 {
                     reinterpret_cast<uint8_t*>(&res)[sizeof(double) - byte - 1] = v[current_idx + 1 + byte];
@@ -7608,7 +9011,9 @@ class basic_json
 
             default: // anything else (0xFF is handled inside the other types)
             {
-                throw std::invalid_argument("error parsing a CBOR @ " + std::to_string(current_idx) + ": " + std::to_string(static_cast<int>(v[current_idx])));
+                std::stringstream ss;
+                ss << std::hex << static_cast<int>(v[current_idx]);
+                JSON_THROW(parse_error::create(112, current_idx + 1, "error reading CBOR; last byte: 0x" + ss.str()));
             }
         }
     }
@@ -7621,6 +9026,58 @@ class basic_json
     serialization format. MessagePack is a binary serialization format which
     aims to be more compact than JSON itself, yet more efficient to parse.
 
+    The library uses the following mapping from JSON values types to
+    MessagePack types according to the MessagePack specification:
+
+    JSON value type | value/range                       | MessagePack type | first byte
+    --------------- | --------------------------------- | ---------------- | ----------
+    null            | `null`                            | nil              | 0xc0
+    boolean         | `true`                            | true             | 0xc3
+    boolean         | `false`                           | false            | 0xc2
+    number_integer  | -9223372036854775808..-2147483649 | int64            | 0xd3
+    number_integer  | -2147483648..-32769               | int32            | 0xd2
+    number_integer  | -32768..-129                      | int16            | 0xd1
+    number_integer  | -128..-33                         | int8             | 0xd0
+    number_integer  | -32..-1                           | negative fixint  | 0xe0..0xff
+    number_integer  | 0..127                            | positive fixint  | 0x00..0x7f
+    number_integer  | 128..255                          | uint 8           | 0xcc
+    number_integer  | 256..65535                        | uint 16          | 0xcd
+    number_integer  | 65536..4294967295                 | uint 32          | 0xce
+    number_integer  | 4294967296..18446744073709551615  | uint 64          | 0xcf
+    number_unsigned | 0..127                            | positive fixint  | 0x00..0x7f
+    number_unsigned | 128..255                          | uint 8           | 0xcc
+    number_unsigned | 256..65535                        | uint 16          | 0xcd
+    number_unsigned | 65536..4294967295                 | uint 32          | 0xce
+    number_unsigned | 4294967296..18446744073709551615  | uint 64          | 0xcf
+    number_float    | *any value*                       | float 64         | 0xcb
+    string          | *length*: 0..31                   | fixstr           | 0xa0..0xbf
+    string          | *length*: 32..255                 | str 8            | 0xd9
+    string          | *length*: 256..65535              | str 16           | 0xda
+    string          | *length*: 65536..4294967295       | str 32           | 0xdb
+    array           | *size*: 0..15                     | fixarray         | 0x90..0x9f
+    array           | *size*: 16..65535                 | array 16         | 0xdc
+    array           | *size*: 65536..4294967295         | array 32         | 0xdd
+    object          | *size*: 0..15                     | fix map          | 0x80..0x8f
+    object          | *size*: 16..65535                 | map 16           | 0xde
+    object          | *size*: 65536..4294967295         | map 32           | 0xdf
+
+    @note The mapping is **complete** in the sense that any JSON value type
+          can be converted to a MessagePack value.
+
+    @note The following values can **not** be converted to a MessagePack value:
+          - strings with more than 4294967295 bytes
+          - arrays with more than 4294967295 elements
+          - objects with more than 4294967295 elements
+
+    @note The following MessagePack types are not used in the conversion:
+          - bin 8 - bin 32 (0xc4..0xc6)
+          - ext 8 - ext 32 (0xc7..0xc9)
+          - float 32 (0xca)
+          - fixext 1 - fixext 16 (0xd4..0xd8)
+
+    @note Any MessagePack output created @ref to_msgpack can be successfully
+          parsed by @ref from_msgpack.
+
     @param[in] j  JSON value to serialize
     @return MessagePack serialization as byte vector
 
@@ -7630,9 +9087,11 @@ class basic_json
     vector in MessagePack format.,to_msgpack}
 
     @sa http://msgpack.org
-    @sa @ref from_msgpack(const std::vector<uint8_t>&) for the analogous
-        deserialization
+    @sa @ref from_msgpack(const std::vector<uint8_t>&, const size_t) for the
+        analogous deserialization
     @sa @ref to_cbor(const basic_json& for the related CBOR format
+
+    @since version 2.0.9
     */
     static std::vector<uint8_t> to_msgpack(const basic_json& j)
     {
@@ -7647,12 +9106,54 @@ class basic_json
     Deserializes a given byte vector @a v to a JSON value using the MessagePack
     serialization format.
 
+    The library maps MessagePack types to JSON value types as follows:
+
+    MessagePack type | JSON value type | first byte
+    ---------------- | --------------- | ----------
+    positive fixint  | number_unsigned | 0x00..0x7f
+    fixmap           | object          | 0x80..0x8f
+    fixarray         | array           | 0x90..0x9f
+    fixstr           | string          | 0xa0..0xbf
+    nil              | `null`          | 0xc0
+    false            | `false`         | 0xc2
+    true             | `true`          | 0xc3
+    float 32         | number_float    | 0xca
+    float 64         | number_float    | 0xcb
+    uint 8           | number_unsigned | 0xcc
+    uint 16          | number_unsigned | 0xcd
+    uint 32          | number_unsigned | 0xce
+    uint 64          | number_unsigned | 0xcf
+    int 8            | number_integer  | 0xd0
+    int 16           | number_integer  | 0xd1
+    int 32           | number_integer  | 0xd2
+    int 64           | number_integer  | 0xd3
+    str 8            | string          | 0xd9
+    str 16           | string          | 0xda
+    str 32           | string          | 0xdb
+    array 16         | array           | 0xdc
+    array 32         | array           | 0xdd
+    map 16           | object          | 0xde
+    map 32           | object          | 0xdf
+    negative fixint  | number_integer  | 0xe0-0xff
+
+    @warning The mapping is **incomplete** in the sense that not all
+             MessagePack types can be converted to a JSON value. The following
+             MessagePack types are not supported and will yield parse errors:
+              - bin 8 - bin 32 (0xc4..0xc6)
+              - ext 8 - ext 32 (0xc7..0xc9)
+              - fixext 1 - fixext 16 (0xd4..0xd8)
+
+    @note Any MessagePack output created @ref to_msgpack can be successfully
+          parsed by @ref from_msgpack.
+
     @param[in] v  a byte vector in MessagePack format
+    @param[in] start_index the index to start reading from @a v (0 by default)
     @return deserialized JSON value
 
-    @throw std::invalid_argument if unsupported features from MessagePack were
+    @throw parse_error.110 if the given vector ends prematurely
+    @throw parse_error.112 if unsupported features from MessagePack were
     used in the given vector @a v or if the input is not valid MessagePack
-    @throw std::out_of_range if the given vector ends prematurely
+    @throw parse_error.113 if a string was expected as map key, but not found
 
     @complexity Linear in the size of the byte vector @a v.
 
@@ -7661,11 +9162,15 @@ class basic_json
 
     @sa http://msgpack.org
     @sa @ref to_msgpack(const basic_json&) for the analogous serialization
-    @sa @ref from_cbor(const std::vector<uint8_t>&) for the related CBOR format
+    @sa @ref from_cbor(const std::vector<uint8_t>&, const size_t) for the
+        related CBOR format
+
+    @since version 2.0.9, parameter @a start_index since 2.1.1
     */
-    static basic_json from_msgpack(const std::vector<uint8_t>& v)
+    static basic_json from_msgpack(const std::vector<uint8_t>& v,
+                                   const size_t start_index = 0)
     {
-        size_t i = 0;
+        size_t i = start_index;
         return from_msgpack_internal(v, i);
     }
 
@@ -7677,6 +9182,65 @@ class basic_json
     serialization format which aims to be more compact than JSON itself, yet
     more efficient to parse.
 
+    The library uses the following mapping from JSON values types to
+    CBOR types according to the CBOR specification (RFC 7049):
+
+    JSON value type | value/range                                | CBOR type                          | first byte
+    --------------- | ------------------------------------------ | ---------------------------------- | ---------------
+    null            | `null`                                     | Null                               | 0xf6
+    boolean         | `true`                                     | True                               | 0xf5
+    boolean         | `false`                                    | False                              | 0xf4
+    number_integer  | -9223372036854775808..-2147483649          | Negative integer (8 bytes follow)  | 0x3b
+    number_integer  | -2147483648..-32769                        | Negative integer (4 bytes follow)  | 0x3a
+    number_integer  | -32768..-129                               | Negative integer (2 bytes follow)  | 0x39
+    number_integer  | -128..-25                                  | Negative integer (1 byte follow)   | 0x38
+    number_integer  | -24..-1                                    | Negative integer                   | 0x20..0x37
+    number_integer  | 0..23                                      | Integer                            | 0x00..0x17
+    number_integer  | 24..255                                    | Unsigned integer (1 byte follow)   | 0x18
+    number_integer  | 256..65535                                 | Unsigned integer (2 bytes follow)  | 0x19
+    number_integer  | 65536..4294967295                          | Unsigned integer (4 bytes follow)  | 0x1a
+    number_integer  | 4294967296..18446744073709551615           | Unsigned integer (8 bytes follow)  | 0x1b
+    number_unsigned | 0..23                                      | Integer                            | 0x00..0x17
+    number_unsigned | 24..255                                    | Unsigned integer (1 byte follow)   | 0x18
+    number_unsigned | 256..65535                                 | Unsigned integer (2 bytes follow)  | 0x19
+    number_unsigned | 65536..4294967295                          | Unsigned integer (4 bytes follow)  | 0x1a
+    number_unsigned | 4294967296..18446744073709551615           | Unsigned integer (8 bytes follow)  | 0x1b
+    number_float    | *any value*                                | Double-Precision Float             | 0xfb
+    string          | *length*: 0..23                            | UTF-8 string                       | 0x60..0x77
+    string          | *length*: 23..255                          | UTF-8 string (1 byte follow)       | 0x78
+    string          | *length*: 256..65535                       | UTF-8 string (2 bytes follow)      | 0x79
+    string          | *length*: 65536..4294967295                | UTF-8 string (4 bytes follow)      | 0x7a
+    string          | *length*: 4294967296..18446744073709551615 | UTF-8 string (8 bytes follow)      | 0x7b
+    array           | *size*: 0..23                              | array                              | 0x80..0x97
+    array           | *size*: 23..255                            | array (1 byte follow)              | 0x98
+    array           | *size*: 256..65535                         | array (2 bytes follow)             | 0x99
+    array           | *size*: 65536..4294967295                  | array (4 bytes follow)             | 0x9a
+    array           | *size*: 4294967296..18446744073709551615   | array (8 bytes follow)             | 0x9b
+    object          | *size*: 0..23                              | map                                | 0xa0..0xb7
+    object          | *size*: 23..255                            | map (1 byte follow)                | 0xb8
+    object          | *size*: 256..65535                         | map (2 bytes follow)               | 0xb9
+    object          | *size*: 65536..4294967295                  | map (4 bytes follow)               | 0xba
+    object          | *size*: 4294967296..18446744073709551615   | map (8 bytes follow)               | 0xbb
+
+    @note The mapping is **complete** in the sense that any JSON value type
+          can be converted to a CBOR value.
+
+    @note The following CBOR types are not used in the conversion:
+          - byte strings (0x40..0x5f)
+          - UTF-8 strings terminated by "break" (0x7f)
+          - arrays terminated by "break" (0x9f)
+          - maps terminated by "break" (0xbf)
+          - date/time (0xc0..0xc1)
+          - bignum (0xc2..0xc3)
+          - decimal fraction (0xc4)
+          - bigfloat (0xc5)
+          - tagged items (0xc6..0xd4, 0xd8..0xdb)
+          - expected conversions (0xd5..0xd7)
+          - simple values (0xe0..0xf3, 0xf8)
+          - undefined (0xf7)
+          - half and single-precision floats (0xf9-0xfa)
+          - break (0xff)
+
     @param[in] j  JSON value to serialize
     @return MessagePack serialization as byte vector
 
@@ -7686,9 +9250,11 @@ class basic_json
     vector in CBOR format.,to_cbor}
 
     @sa http://cbor.io
-    @sa @ref from_cbor(const std::vector<uint8_t>&) for the analogous
-        deserialization
+    @sa @ref from_cbor(const std::vector<uint8_t>&, const size_t) for the
+        analogous deserialization
     @sa @ref to_msgpack(const basic_json& for the related MessagePack format
+
+    @since version 2.0.9
     */
     static std::vector<uint8_t> to_cbor(const basic_json& j)
     {
@@ -7703,12 +9269,74 @@ class basic_json
     Deserializes a given byte vector @a v to a JSON value using the CBOR
     (Concise Binary Object Representation) serialization format.
 
+    The library maps CBOR types to JSON value types as follows:
+
+    CBOR type              | JSON value type | first byte
+    ---------------------- | --------------- | ----------
+    Integer                | number_unsigned | 0x00..0x17
+    Unsigned integer       | number_unsigned | 0x18
+    Unsigned integer       | number_unsigned | 0x19
+    Unsigned integer       | number_unsigned | 0x1a
+    Unsigned integer       | number_unsigned | 0x1b
+    Negative integer       | number_integer  | 0x20..0x37
+    Negative integer       | number_integer  | 0x38
+    Negative integer       | number_integer  | 0x39
+    Negative integer       | number_integer  | 0x3a
+    Negative integer       | number_integer  | 0x3b
+    Negative integer       | number_integer  | 0x40..0x57
+    UTF-8 string           | string          | 0x60..0x77
+    UTF-8 string           | string          | 0x78
+    UTF-8 string           | string          | 0x79
+    UTF-8 string           | string          | 0x7a
+    UTF-8 string           | string          | 0x7b
+    UTF-8 string           | string          | 0x7f
+    array                  | array           | 0x80..0x97
+    array                  | array           | 0x98
+    array                  | array           | 0x99
+    array                  | array           | 0x9a
+    array                  | array           | 0x9b
+    array                  | array           | 0x9f
+    map                    | object          | 0xa0..0xb7
+    map                    | object          | 0xb8
+    map                    | object          | 0xb9
+    map                    | object          | 0xba
+    map                    | object          | 0xbb
+    map                    | object          | 0xbf
+    False                  | `false`         | 0xf4
+    True                   | `true`          | 0xf5
+    Nill                   | `null`          | 0xf6
+    Half-Precision Float   | number_float    | 0xf9
+    Single-Precision Float | number_float    | 0xfa
+    Double-Precision Float | number_float    | 0xfb
+
+    @warning The mapping is **incomplete** in the sense that not all CBOR
+             types can be converted to a JSON value. The following CBOR types
+             are not supported and will yield parse errors (parse_error.112):
+             - byte strings (0x40..0x5f)
+             - date/time (0xc0..0xc1)
+             - bignum (0xc2..0xc3)
+             - decimal fraction (0xc4)
+             - bigfloat (0xc5)
+             - tagged items (0xc6..0xd4, 0xd8..0xdb)
+             - expected conversions (0xd5..0xd7)
+             - simple values (0xe0..0xf3, 0xf8)
+             - undefined (0xf7)
+
+    @warning CBOR allows map keys of any type, whereas JSON only allows
+             strings as keys in object values. Therefore, CBOR maps with keys
+             other than UTF-8 strings are rejected (parse_error.113).
+
+    @note Any CBOR output created @ref to_cbor can be successfully parsed by
+          @ref from_cbor.
+
     @param[in] v  a byte vector in CBOR format
+    @param[in] start_index the index to start reading from @a v (0 by default)
     @return deserialized JSON value
 
-    @throw std::invalid_argument if unsupported features from CBOR were used in
-    the given vector @a v or if the input is not valid MessagePack
-    @throw std::out_of_range if the given vector ends prematurely
+    @throw parse_error.110 if the given vector ends prematurely
+    @throw parse_error.112 if unsupported features from CBOR were
+    used in the given vector @a v or if the input is not valid CBOR
+    @throw parse_error.113 if a string was expected as map key, but not found
 
     @complexity Linear in the size of the byte vector @a v.
 
@@ -7717,375 +9345,63 @@ class basic_json
 
     @sa http://cbor.io
     @sa @ref to_cbor(const basic_json&) for the analogous serialization
-    @sa @ref from_msgpack(const std::vector<uint8_t>&) for the related
-        MessagePack format
-    */
-    static basic_json from_cbor(const std::vector<uint8_t>& v)
-    {
-        size_t i = 0;
-        return from_cbor_internal(v, i);
-    }
-
-    /// @}
-
-  private:
-    ///////////////////////////
-    // convenience functions //
-    ///////////////////////////
-
-    /*!
-    @brief return the type as string
-
-    Returns the type name as string to be used in error messages - usually to
-    indicate that a function was called on a wrong JSON type.
-
-    @return basically a string representation of a the @a m_type member
-
-    @complexity Constant.
-
-    @since version 1.0.0
-    */
-    std::string type_name() const
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-                return "null";
-            case value_t::object:
-                return "object";
-            case value_t::array:
-                return "array";
-            case value_t::string:
-                return "string";
-            case value_t::boolean:
-                return "boolean";
-            case value_t::discarded:
-                return "discarded";
-            default:
-                return "number";
-        }
-    }
-
-    /*!
-    @brief calculates the extra space to escape a JSON string
-
-    @param[in] s  the string to escape
-    @return the number of characters required to escape string @a s
-
-    @complexity Linear in the length of string @a s.
-    */
-    static std::size_t extra_space(const string_t& s) noexcept
-    {
-        return std::accumulate(s.begin(), s.end(), size_t{},
-                               [](size_t res, typename string_t::value_type c)
-        {
-            switch (c)
-            {
-                case '"':
-                case '\\':
-                case '\b':
-                case '\f':
-                case '\n':
-                case '\r':
-                case '\t':
-                {
-                    // from c (1 byte) to \x (2 bytes)
-                    return res + 1;
-                }
-
-                default:
-                {
-                    if (c >= 0x00 and c <= 0x1f)
-                    {
-                        // from c (1 byte) to \uxxxx (6 bytes)
-                        return res + 5;
-                    }
-                    else
-                    {
-                        return res;
-                    }
-                }
-            }
-        });
-    }
-
-    /*!
-    @brief escape a string
-
-    Escape a string by replacing certain special characters by a sequence of
-    an escape character (backslash) and another character and other control
-    characters by a sequence of "\u" followed by a four-digit hex
-    representation.
-
-    @param[in] s  the string to escape
-    @return  the escaped string
-
-    @complexity Linear in the length of string @a s.
-    */
-    static string_t escape_string(const string_t& s)
-    {
-        const auto space = extra_space(s);
-        if (space == 0)
-        {
-            return s;
-        }
-
-        // create a result string of necessary size
-        string_t result(s.size() + space, '\\');
-        std::size_t pos = 0;
-
-        for (const auto& c : s)
-        {
-            switch (c)
-            {
-                // quotation mark (0x22)
-                case '"':
-                {
-                    result[pos + 1] = '"';
-                    pos += 2;
-                    break;
-                }
-
-                // reverse solidus (0x5c)
-                case '\\':
-                {
-                    // nothing to change
-                    pos += 2;
-                    break;
-                }
-
-                // backspace (0x08)
-                case '\b':
-                {
-                    result[pos + 1] = 'b';
-                    pos += 2;
-                    break;
-                }
-
-                // formfeed (0x0c)
-                case '\f':
-                {
-                    result[pos + 1] = 'f';
-                    pos += 2;
-                    break;
-                }
-
-                // newline (0x0a)
-                case '\n':
-                {
-                    result[pos + 1] = 'n';
-                    pos += 2;
-                    break;
-                }
-
-                // carriage return (0x0d)
-                case '\r':
-                {
-                    result[pos + 1] = 'r';
-                    pos += 2;
-                    break;
-                }
-
-                // horizontal tab (0x09)
-                case '\t':
-                {
-                    result[pos + 1] = 't';
-                    pos += 2;
-                    break;
-                }
-
-                default:
-                {
-                    if (c >= 0x00 and c <= 0x1f)
-                    {
-                        // convert a number 0..15 to its hex representation
-                        // (0..f)
-                        static const char hexify[16] =
-                        {
-                            '0', '1', '2', '3', '4', '5', '6', '7',
-                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
-                        };
-
-                        // print character c as \uxxxx
-                        for (const char m :
-                    { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f]
-                        })
-                        {
-                            result[++pos] = m;
-                        }
-
-                        ++pos;
-                    }
-                    else
-                    {
-                        // all other characters are added as-is
-                        result[pos++] = c;
-                    }
-                    break;
-                }
-            }
-        }
-
-        return result;
-    }
-
-    /*!
-    @brief internal implementation of the serialization function
-
-    This function is called by the public member function dump and organizes
-    the serialization internally. The indentation level is propagated as
-    additional parameter. In case of arrays and objects, the function is
-    called recursively. Note that
-
-    - strings and object keys are escaped using `escape_string()`
-    - integer numbers are converted implicitly via `operator<<`
-    - floating-point numbers are converted to a string using `"%g"` format
-
-    @param[out] o              stream to write to
-    @param[in] pretty_print    whether the output shall be pretty-printed
-    @param[in] indent_step     the indent level
-    @param[in] current_indent  the current indent level (only used internally)
-    */
-    void dump(std::ostream& o,
-              const bool pretty_print,
-              const unsigned int indent_step,
-              const unsigned int current_indent = 0) const
-    {
-        // variable to hold indentation for recursive calls
-        unsigned int new_indent = current_indent;
-
-        switch (m_type)
-        {
-            case value_t::object:
-            {
-                if (m_value.object->empty())
-                {
-                    o << "{}";
-                    return;
-                }
-
-                o << "{";
-
-                // increase indentation
-                if (pretty_print)
-                {
-                    new_indent += indent_step;
-                    o << "\n";
-                }
-
-                for (auto i = m_value.object->cbegin(); i != m_value.object->cend(); ++i)
-                {
-                    if (i != m_value.object->cbegin())
-                    {
-                        o << (pretty_print ? ",\n" : ",");
-                    }
-                    o << string_t(new_indent, ' ') << "\""
-                      << escape_string(i->first) << "\":"
-                      << (pretty_print ? " " : "");
-                    i->second.dump(o, pretty_print, indent_step, new_indent);
-                }
-
-                // decrease indentation
-                if (pretty_print)
-                {
-                    new_indent -= indent_step;
-                    o << "\n";
-                }
-
-                o << string_t(new_indent, ' ') + "}";
-                return;
-            }
-
-            case value_t::array:
-            {
-                if (m_value.array->empty())
-                {
-                    o << "[]";
-                    return;
-                }
-
-                o << "[";
-
-                // increase indentation
-                if (pretty_print)
-                {
-                    new_indent += indent_step;
-                    o << "\n";
-                }
-
-                for (auto i = m_value.array->cbegin(); i != m_value.array->cend(); ++i)
-                {
-                    if (i != m_value.array->cbegin())
-                    {
-                        o << (pretty_print ? ",\n" : ",");
-                    }
-                    o << string_t(new_indent, ' ');
-                    i->dump(o, pretty_print, indent_step, new_indent);
-                }
+    @sa @ref from_msgpack(const std::vector<uint8_t>&, const size_t) for the
+        related MessagePack format
 
-                // decrease indentation
-                if (pretty_print)
-                {
-                    new_indent -= indent_step;
-                    o << "\n";
-                }
+    @since version 2.0.9, parameter @a start_index since 2.1.1
+    */
+    static basic_json from_cbor(const std::vector<uint8_t>& v,
+                                const size_t start_index = 0)
+    {
+        size_t i = start_index;
+        return from_cbor_internal(v, i);
+    }
 
-                o << string_t(new_indent, ' ') << "]";
-                return;
-            }
+    /// @}
 
-            case value_t::string:
-            {
-                o << string_t("\"") << escape_string(*m_value.string) << "\"";
-                return;
-            }
+    ///////////////////////////
+    // convenience functions //
+    ///////////////////////////
 
-            case value_t::boolean:
-            {
-                o << (m_value.boolean ? "true" : "false");
-                return;
-            }
+    /*!
+    @brief return the type as string
 
-            case value_t::number_integer:
-            {
-                o << m_value.number_integer;
-                return;
-            }
+    Returns the type name as string to be used in error messages - usually to
+    indicate that a function was called on a wrong JSON type.
 
-            case value_t::number_unsigned:
-            {
-                o << m_value.number_unsigned;
-                return;
-            }
+    @return basically a string representation of a the @a m_type member
 
-            case value_t::number_float:
-            {
-                if (m_value.number_float == 0)
-                {
-                    // special case for zero to get "0.0"/"-0.0"
-                    o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
-                }
-                else
-                {
-                    o << m_value.number_float;
-                }
-                return;
-            }
+    @complexity Constant.
 
-            case value_t::discarded:
-            {
-                o << "<discarded>";
-                return;
-            }
+    @liveexample{The following code exemplifies `type_name()` for all JSON
+    types.,type_name}
 
-            case value_t::null:
+    @since version 1.0.0, public since 2.1.0
+    */
+    std::string type_name() const
+    {
+        {
+            switch (m_type)
             {
-                o << "null";
-                return;
+                case value_t::null:
+                    return "null";
+                case value_t::object:
+                    return "object";
+                case value_t::array:
+                    return "array";
+                case value_t::string:
+                    return "string";
+                case value_t::boolean:
+                    return "boolean";
+                case value_t::discarded:
+                    return "discarded";
+                default:
+                    return "number";
             }
         }
     }
 
+
   private:
     //////////////////////
     // member variables //
@@ -8115,6 +9431,11 @@ class basic_json
     class primitive_iterator_t
     {
       public:
+
+        difference_type get_value() const noexcept
+        {
+            return m_it;
+        }
         /// set iterator to a defined beginning
         void set_begin() noexcept
         {
@@ -8139,16 +9460,89 @@ class basic_json
             return (m_it == end_value);
         }
 
-        /// return reference to the value to change and compare
-        operator difference_type& () noexcept
+        friend constexpr bool operator==(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
         {
-            return m_it;
+            return lhs.m_it == rhs.m_it;
         }
 
-        /// return value to compare
-        constexpr operator difference_type () const noexcept
+        friend constexpr bool operator!=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
         {
-            return m_it;
+            return !(lhs == rhs);
+        }
+
+        friend constexpr bool operator<(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+        {
+            return lhs.m_it < rhs.m_it;
+        }
+
+        friend constexpr bool operator<=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+        {
+            return lhs.m_it <= rhs.m_it;
+        }
+
+        friend constexpr bool operator>(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+        {
+            return lhs.m_it > rhs.m_it;
+        }
+
+        friend constexpr bool operator>=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+        {
+            return lhs.m_it >= rhs.m_it;
+        }
+
+        primitive_iterator_t operator+(difference_type i)
+        {
+            auto result = *this;
+            result += i;
+            return result;
+        }
+
+        friend constexpr difference_type operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+        {
+            return lhs.m_it - rhs.m_it;
+        }
+
+        friend std::ostream& operator<<(std::ostream& os, primitive_iterator_t it)
+        {
+            return os << it.m_it;
+        }
+
+        primitive_iterator_t& operator++()
+        {
+            ++m_it;
+            return *this;
+        }
+
+        primitive_iterator_t operator++(int)
+        {
+            auto result = *this;
+            m_it++;
+            return result;
+        }
+
+        primitive_iterator_t& operator--()
+        {
+            --m_it;
+            return *this;
+        }
+
+        primitive_iterator_t operator--(int)
+        {
+            auto result = *this;
+            m_it--;
+            return result;
+        }
+
+        primitive_iterator_t& operator+=(difference_type n)
+        {
+            m_it += n;
+            return *this;
+        }
+
+        primitive_iterator_t& operator-=(difference_type n)
+        {
+            m_it -= n;
+            return *this;
         }
 
       private:
@@ -8500,7 +9894,7 @@ class basic_json
 
                 case basic_json::value_t::null:
                 {
-                    throw std::out_of_range("cannot get value");
+                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
                 }
 
                 default:
@@ -8509,10 +9903,8 @@ class basic_json
                     {
                         return *m_object;
                     }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
+
+                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
                 }
             }
         }
@@ -8545,10 +9937,8 @@ class basic_json
                     {
                         return m_object;
                     }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
+
+                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
                 }
             }
         }
@@ -8648,7 +10038,7 @@ class basic_json
             // if objects are not the same, the comparison is undefined
             if (m_object != other.m_object)
             {
-                throw std::domain_error("cannot compare iterators of different containers");
+                JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
             }
 
             assert(m_object != nullptr);
@@ -8690,7 +10080,7 @@ class basic_json
             // if objects are not the same, the comparison is undefined
             if (m_object != other.m_object)
             {
-                throw std::domain_error("cannot compare iterators of different containers");
+                JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
             }
 
             assert(m_object != nullptr);
@@ -8699,7 +10089,7 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    throw std::domain_error("cannot compare order of object iterators");
+                    JSON_THROW(invalid_iterator::create(213, "cannot compare order of object iterators"));
                 }
 
                 case basic_json::value_t::array:
@@ -8753,7 +10143,7 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    throw std::domain_error("cannot use offsets with object iterators");
+                    JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));
                 }
 
                 case basic_json::value_t::array:
@@ -8815,7 +10205,7 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    throw std::domain_error("cannot use offsets with object iterators");
+                    JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));
                 }
 
                 case basic_json::value_t::array:
@@ -8842,7 +10232,7 @@ class basic_json
             {
                 case basic_json::value_t::object:
                 {
-                    throw std::domain_error("cannot use operator[] for object iterators");
+                    JSON_THROW(invalid_iterator::create(208, "cannot use operator[] for object iterators"));
                 }
 
                 case basic_json::value_t::array:
@@ -8852,19 +10242,17 @@ class basic_json
 
                 case basic_json::value_t::null:
                 {
-                    throw std::out_of_range("cannot get value");
+                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
                 }
 
                 default:
                 {
-                    if (m_it.primitive_iterator == -n)
+                    if (m_it.primitive_iterator.get_value() == -n)
                     {
                         return *m_object;
                     }
-                    else
-                    {
-                        throw std::out_of_range("cannot get value");
-                    }
+
+                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
                 }
             }
         }
@@ -8881,10 +10269,8 @@ class basic_json
             {
                 return m_it.object_iterator->first;
             }
-            else
-            {
-                throw std::domain_error("cannot use key() for non-object iterators");
-            }
+
+            JSON_THROW(invalid_iterator::create(207, "cannot use key() for non-object iterators"));
         }
 
         /*!
@@ -9039,7 +10425,9 @@ class basic_json
             literal_false,   ///< the `false` literal
             literal_null,    ///< the `null` literal
             value_string,    ///< a string -- use get_string() for actual value
-            value_number,    ///< a number -- use get_number() for actual value
+            value_unsigned,  ///< an unsigned integer -- use get_number() for actual value
+            value_integer,   ///< a signed integer -- use get_number() for actual value
+            value_float,     ///< an floating point number -- use get_number() for actual value
             begin_array,     ///< the character for array begin `[`
             begin_object,    ///< the character for object begin `{`
             end_array,       ///< the character for array end `]`
@@ -9062,14 +10450,17 @@ class basic_json
             m_limit = m_content + len;
         }
 
-        /// a lexer from an input stream
+        /*!
+        @brief a lexer from an input stream
+        @throw parse_error.111 if input stream is in a bad state
+        */
         explicit lexer(std::istream& s)
             : m_stream(&s), m_line_buffer()
         {
             // immediately abort if stream is erroneous
             if (s.fail())
             {
-                throw std::invalid_argument("stream error");
+                JSON_THROW(parse_error::create(111, 0, "bad input stream"));
             }
 
             // fill buffer
@@ -9103,17 +10494,17 @@ class basic_json
         @return string representation of the code point; the length of the
         result string is between 1 and 4 characters.
 
-        @throw std::out_of_range if code point is > 0x10ffff; example: `"code
-        points above 0x10FFFF are invalid"`
-        @throw std::invalid_argument if the low surrogate is invalid; example:
+        @throw parse_error.102 if the low surrogate is invalid; example:
         `""missing or wrong low surrogate""`
+        @throw parse_error.103 if code point is > 0x10ffff; example: `"code
+        points above 0x10FFFF are invalid"`
 
         @complexity Constant.
 
         @see <http://en.wikipedia.org/wiki/UTF-8#Sample_code>
         */
-        static string_t to_unicode(const std::size_t codepoint1,
-                                   const std::size_t codepoint2 = 0)
+        string_t to_unicode(const std::size_t codepoint1,
+                            const std::size_t codepoint2 = 0) const
         {
             // calculate the code point from the given code points
             std::size_t codepoint = codepoint1;
@@ -9136,7 +10527,7 @@ class basic_json
                 }
                 else
                 {
-                    throw std::invalid_argument("missing or wrong low surrogate");
+                    JSON_THROW(parse_error::create(102, get_position(), "missing or wrong low surrogate"));
                 }
             }
 
@@ -9150,27 +10541,27 @@ class basic_json
             else if (codepoint <= 0x7ff)
             {
                 // 2-byte characters: 110xxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xC0 | ((codepoint >> 6) & 0x1F)));
+                result.append(1, static_cast<typename string_t::value_type>(0xC0 | (codepoint >> 6)));
                 result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
             }
             else if (codepoint <= 0xffff)
             {
                 // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xE0 | ((codepoint >> 12) & 0x0F)));
+                result.append(1, static_cast<typename string_t::value_type>(0xE0 | (codepoint >> 12)));
                 result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
                 result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
             }
             else if (codepoint <= 0x10ffff)
             {
                 // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xF0 | ((codepoint >> 18) & 0x07)));
+                result.append(1, static_cast<typename string_t::value_type>(0xF0 | (codepoint >> 18)));
                 result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 12) & 0x3F)));
                 result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
                 result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
             }
             else
             {
-                throw std::out_of_range("code points above 0x10FFFF are invalid");
+                JSON_THROW(parse_error::create(103, get_position(), "code points above 0x10FFFF are invalid"));
             }
 
             return result;
@@ -9191,7 +10582,9 @@ class basic_json
                     return "null literal";
                 case token_type::value_string:
                     return "string literal";
-                case token_type::value_number:
+                case lexer::token_type::value_unsigned:
+                case lexer::token_type::value_integer:
+                case lexer::token_type::value_float:
                     return "number literal";
                 case token_type::begin_array:
                     return "'['";
@@ -9233,10 +10626,9 @@ class basic_json
 
         Proof (by contradiction): Assume a finite input. To loop forever, the
         loop must never hit code with a `break` statement. The only code
-        snippets without a `break` statement are the continue statements for
-        whitespace and byte-order-marks. To loop forever, the input must be an
-        infinite sequence of whitespace or byte-order-marks. This contradicts
-        the assumption of finite input, q.e.d.
+        snippets without a `break` statement is the continue statement for
+        whitespace. To loop forever, the input must be an infinite sequence
+        whitespace. This contradicts the assumption of finite input, q.e.d.
         */
         token_type scan()
         {
@@ -9428,6 +10820,7 @@ basic_json_parser_6:
                         goto basic_json_parser_6;
                     }
                     {
+                        position += static_cast<size_t>((m_cursor - m_start));
                         continue;
                     }
 basic_json_parser_9:
@@ -9464,37 +10857,47 @@ basic_json_parser_12:
                     }
                     if (yych <= '0')
                     {
-                        goto basic_json_parser_13;
+                        goto basic_json_parser_43;
                     }
                     if (yych <= '9')
                     {
-                        goto basic_json_parser_15;
+                        goto basic_json_parser_45;
                     }
                     goto basic_json_parser_5;
 basic_json_parser_13:
                     yyaccept = 1;
                     yych = *(m_marker = ++m_cursor);
-                    if (yych <= 'D')
+                    if (yych <= '9')
                     {
                         if (yych == '.')
                         {
-                            goto basic_json_parser_43;
+                            goto basic_json_parser_47;
+                        }
+                        if (yych >= '0')
+                        {
+                            goto basic_json_parser_48;
                         }
                     }
                     else
                     {
                         if (yych <= 'E')
                         {
-                            goto basic_json_parser_44;
+                            if (yych >= 'E')
+                            {
+                                goto basic_json_parser_51;
+                            }
                         }
-                        if (yych == 'e')
+                        else
                         {
-                            goto basic_json_parser_44;
+                            if (yych == 'e')
+                            {
+                                goto basic_json_parser_51;
+                            }
                         }
                     }
 basic_json_parser_14:
                     {
-                        last_token_type = token_type::value_number;
+                        last_token_type = token_type::value_unsigned;
                         break;
                     }
 basic_json_parser_15:
@@ -9513,7 +10916,7 @@ basic_json_parser_15:
                     {
                         if (yych == '.')
                         {
-                            goto basic_json_parser_43;
+                            goto basic_json_parser_47;
                         }
                         goto basic_json_parser_14;
                     }
@@ -9521,11 +10924,11 @@ basic_json_parser_15:
                     {
                         if (yych <= 'E')
                         {
-                            goto basic_json_parser_44;
+                            goto basic_json_parser_51;
                         }
                         if (yych == 'e')
                         {
-                            goto basic_json_parser_44;
+                            goto basic_json_parser_51;
                         }
                         goto basic_json_parser_14;
                     }
@@ -9552,7 +10955,7 @@ basic_json_parser_23:
                     yych = *(m_marker = ++m_cursor);
                     if (yych == 'a')
                     {
-                        goto basic_json_parser_45;
+                        goto basic_json_parser_52;
                     }
                     goto basic_json_parser_5;
 basic_json_parser_24:
@@ -9560,7 +10963,7 @@ basic_json_parser_24:
                     yych = *(m_marker = ++m_cursor);
                     if (yych == 'u')
                     {
-                        goto basic_json_parser_46;
+                        goto basic_json_parser_53;
                     }
                     goto basic_json_parser_5;
 basic_json_parser_25:
@@ -9568,7 +10971,7 @@ basic_json_parser_25:
                     yych = *(m_marker = ++m_cursor);
                     if (yych == 'r')
                     {
-                        goto basic_json_parser_47;
+                        goto basic_json_parser_54;
                     }
                     goto basic_json_parser_5;
 basic_json_parser_26:
@@ -9650,13 +11053,27 @@ basic_json_parser_31:
                     }
 basic_json_parser_32:
                     m_cursor = m_marker;
-                    if (yyaccept == 0)
+                    if (yyaccept <= 1)
                     {
-                        goto basic_json_parser_5;
+                        if (yyaccept == 0)
+                        {
+                            goto basic_json_parser_5;
+                        }
+                        else
+                        {
+                            goto basic_json_parser_14;
+                        }
                     }
                     else
                     {
-                        goto basic_json_parser_14;
+                        if (yyaccept == 2)
+                        {
+                            goto basic_json_parser_44;
+                        }
+                        else
+                        {
+                            goto basic_json_parser_58;
+                        }
                     }
 basic_json_parser_33:
                     ++m_cursor;
@@ -9737,7 +11154,7 @@ basic_json_parser_35:
                                 }
                                 if (yych <= 'u')
                                 {
-                                    goto basic_json_parser_48;
+                                    goto basic_json_parser_55;
                                 }
                                 goto basic_json_parser_32;
                             }
@@ -9836,43 +11253,138 @@ basic_json_parser_41:
                     }
                     if (yych <= 0xBF)
                     {
-                        goto basic_json_parser_38;
+                        goto basic_json_parser_38;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_42:
+                    ++m_cursor;
+                    if (m_limit <= m_cursor)
+                    {
+                        fill_line_buffer(1);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= 0x7F)
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= 0x8F)
+                    {
+                        goto basic_json_parser_38;
+                    }
+                    goto basic_json_parser_32;
+basic_json_parser_43:
+                    yyaccept = 2;
+                    yych = *(m_marker = ++m_cursor);
+                    if (yych <= '9')
+                    {
+                        if (yych == '.')
+                        {
+                            goto basic_json_parser_47;
+                        }
+                        if (yych >= '0')
+                        {
+                            goto basic_json_parser_48;
+                        }
+                    }
+                    else
+                    {
+                        if (yych <= 'E')
+                        {
+                            if (yych >= 'E')
+                            {
+                                goto basic_json_parser_51;
+                            }
+                        }
+                        else
+                        {
+                            if (yych == 'e')
+                            {
+                                goto basic_json_parser_51;
+                            }
+                        }
+                    }
+basic_json_parser_44:
+                    {
+                        last_token_type = token_type::value_integer;
+                        break;
+                    }
+basic_json_parser_45:
+                    yyaccept = 2;
+                    m_marker = ++m_cursor;
+                    if ((m_limit - m_cursor) < 3)
+                    {
+                        fill_line_buffer(3);    // LCOV_EXCL_LINE
+                    }
+                    yych = *m_cursor;
+                    if (yych <= '9')
+                    {
+                        if (yych == '.')
+                        {
+                            goto basic_json_parser_47;
+                        }
+                        if (yych <= '/')
+                        {
+                            goto basic_json_parser_44;
+                        }
+                        goto basic_json_parser_45;
+                    }
+                    else
+                    {
+                        if (yych <= 'E')
+                        {
+                            if (yych <= 'D')
+                            {
+                                goto basic_json_parser_44;
+                            }
+                            goto basic_json_parser_51;
+                        }
+                        else
+                        {
+                            if (yych == 'e')
+                            {
+                                goto basic_json_parser_51;
+                            }
+                            goto basic_json_parser_44;
+                        }
+                    }
+basic_json_parser_47:
+                    yych = *++m_cursor;
+                    if (yych <= '/')
+                    {
+                        goto basic_json_parser_32;
+                    }
+                    if (yych <= '9')
+                    {
+                        goto basic_json_parser_56;
                     }
                     goto basic_json_parser_32;
-basic_json_parser_42:
+basic_json_parser_48:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
                         fill_line_buffer(1);    // LCOV_EXCL_LINE
                     }
                     yych = *m_cursor;
-                    if (yych <= 0x7F)
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= 0x8F)
-                    {
-                        goto basic_json_parser_38;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_43:
-                    yych = *++m_cursor;
                     if (yych <= '/')
                     {
-                        goto basic_json_parser_32;
+                        goto basic_json_parser_50;
                     }
                     if (yych <= '9')
                     {
-                        goto basic_json_parser_49;
+                        goto basic_json_parser_48;
                     }
-                    goto basic_json_parser_32;
-basic_json_parser_44:
+basic_json_parser_50:
+                    {
+                        last_token_type = token_type::parse_error;
+                        break;
+                    }
+basic_json_parser_51:
                     yych = *++m_cursor;
                     if (yych <= ',')
                     {
                         if (yych == '+')
                         {
-                            goto basic_json_parser_51;
+                            goto basic_json_parser_59;
                         }
                         goto basic_json_parser_32;
                     }
@@ -9880,7 +11392,7 @@ basic_json_parser_44:
                     {
                         if (yych <= '-')
                         {
-                            goto basic_json_parser_51;
+                            goto basic_json_parser_59;
                         }
                         if (yych <= '/')
                         {
@@ -9888,32 +11400,32 @@ basic_json_parser_44:
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_52;
+                            goto basic_json_parser_60;
                         }
                         goto basic_json_parser_32;
                     }
-basic_json_parser_45:
+basic_json_parser_52:
                     yych = *++m_cursor;
                     if (yych == 'l')
                     {
-                        goto basic_json_parser_54;
+                        goto basic_json_parser_62;
                     }
                     goto basic_json_parser_32;
-basic_json_parser_46:
+basic_json_parser_53:
                     yych = *++m_cursor;
                     if (yych == 'l')
                     {
-                        goto basic_json_parser_55;
+                        goto basic_json_parser_63;
                     }
                     goto basic_json_parser_32;
-basic_json_parser_47:
+basic_json_parser_54:
                     yych = *++m_cursor;
                     if (yych == 'u')
                     {
-                        goto basic_json_parser_56;
+                        goto basic_json_parser_64;
                     }
                     goto basic_json_parser_32;
-basic_json_parser_48:
+basic_json_parser_55:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
@@ -9928,7 +11440,7 @@ basic_json_parser_48:
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_57;
+                            goto basic_json_parser_65;
                         }
                         goto basic_json_parser_32;
                     }
@@ -9936,7 +11448,7 @@ basic_json_parser_48:
                     {
                         if (yych <= 'F')
                         {
-                            goto basic_json_parser_57;
+                            goto basic_json_parser_65;
                         }
                         if (yych <= '`')
                         {
@@ -9944,12 +11456,12 @@ basic_json_parser_48:
                         }
                         if (yych <= 'f')
                         {
-                            goto basic_json_parser_57;
+                            goto basic_json_parser_65;
                         }
                         goto basic_json_parser_32;
                     }
-basic_json_parser_49:
-                    yyaccept = 1;
+basic_json_parser_56:
+                    yyaccept = 3;
                     m_marker = ++m_cursor;
                     if ((m_limit - m_cursor) < 3)
                     {
@@ -9960,27 +11472,30 @@ basic_json_parser_49:
                     {
                         if (yych <= '/')
                         {
-                            goto basic_json_parser_14;
+                            goto basic_json_parser_58;
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_49;
+                            goto basic_json_parser_56;
                         }
-                        goto basic_json_parser_14;
                     }
                     else
                     {
                         if (yych <= 'E')
                         {
-                            goto basic_json_parser_44;
+                            goto basic_json_parser_51;
                         }
                         if (yych == 'e')
                         {
-                            goto basic_json_parser_44;
+                            goto basic_json_parser_51;
                         }
-                        goto basic_json_parser_14;
                     }
-basic_json_parser_51:
+basic_json_parser_58:
+                    {
+                        last_token_type = token_type::value_float;
+                        break;
+                    }
+basic_json_parser_59:
                     yych = *++m_cursor;
                     if (yych <= '/')
                     {
@@ -9990,7 +11505,7 @@ basic_json_parser_51:
                     {
                         goto basic_json_parser_32;
                     }
-basic_json_parser_52:
+basic_json_parser_60:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
@@ -9999,35 +11514,35 @@ basic_json_parser_52:
                     yych = *m_cursor;
                     if (yych <= '/')
                     {
-                        goto basic_json_parser_14;
+                        goto basic_json_parser_58;
                     }
                     if (yych <= '9')
                     {
-                        goto basic_json_parser_52;
+                        goto basic_json_parser_60;
                     }
-                    goto basic_json_parser_14;
-basic_json_parser_54:
+                    goto basic_json_parser_58;
+basic_json_parser_62:
                     yych = *++m_cursor;
                     if (yych == 's')
                     {
-                        goto basic_json_parser_58;
+                        goto basic_json_parser_66;
                     }
                     goto basic_json_parser_32;
-basic_json_parser_55:
+basic_json_parser_63:
                     yych = *++m_cursor;
                     if (yych == 'l')
                     {
-                        goto basic_json_parser_59;
+                        goto basic_json_parser_67;
                     }
                     goto basic_json_parser_32;
-basic_json_parser_56:
+basic_json_parser_64:
                     yych = *++m_cursor;
                     if (yych == 'e')
                     {
-                        goto basic_json_parser_61;
+                        goto basic_json_parser_69;
                     }
                     goto basic_json_parser_32;
-basic_json_parser_57:
+basic_json_parser_65:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
@@ -10042,7 +11557,7 @@ basic_json_parser_57:
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_63;
+                            goto basic_json_parser_71;
                         }
                         goto basic_json_parser_32;
                     }
@@ -10050,7 +11565,7 @@ basic_json_parser_57:
                     {
                         if (yych <= 'F')
                         {
-                            goto basic_json_parser_63;
+                            goto basic_json_parser_71;
                         }
                         if (yych <= '`')
                         {
@@ -10058,30 +11573,30 @@ basic_json_parser_57:
                         }
                         if (yych <= 'f')
                         {
-                            goto basic_json_parser_63;
+                            goto basic_json_parser_71;
                         }
                         goto basic_json_parser_32;
                     }
-basic_json_parser_58:
+basic_json_parser_66:
                     yych = *++m_cursor;
                     if (yych == 'e')
                     {
-                        goto basic_json_parser_64;
+                        goto basic_json_parser_72;
                     }
                     goto basic_json_parser_32;
-basic_json_parser_59:
+basic_json_parser_67:
                     ++m_cursor;
                     {
                         last_token_type = token_type::literal_null;
                         break;
                     }
-basic_json_parser_61:
+basic_json_parser_69:
                     ++m_cursor;
                     {
                         last_token_type = token_type::literal_true;
                         break;
                     }
-basic_json_parser_63:
+basic_json_parser_71:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
@@ -10096,7 +11611,7 @@ basic_json_parser_63:
                         }
                         if (yych <= '9')
                         {
-                            goto basic_json_parser_66;
+                            goto basic_json_parser_74;
                         }
                         goto basic_json_parser_32;
                     }
@@ -10104,7 +11619,7 @@ basic_json_parser_63:
                     {
                         if (yych <= 'F')
                         {
-                            goto basic_json_parser_66;
+                            goto basic_json_parser_74;
                         }
                         if (yych <= '`')
                         {
@@ -10112,17 +11627,17 @@ basic_json_parser_63:
                         }
                         if (yych <= 'f')
                         {
-                            goto basic_json_parser_66;
+                            goto basic_json_parser_74;
                         }
                         goto basic_json_parser_32;
                     }
-basic_json_parser_64:
+basic_json_parser_72:
                     ++m_cursor;
                     {
                         last_token_type = token_type::literal_false;
                         break;
                     }
-basic_json_parser_66:
+basic_json_parser_74:
                     ++m_cursor;
                     if (m_limit <= m_cursor)
                     {
@@ -10161,6 +11676,7 @@ basic_json_parser_66:
 
             }
 
+            position += static_cast<size_t>((m_cursor - m_start));
             return last_token_type;
         }
 
@@ -10209,7 +11725,7 @@ basic_json_parser_66:
             assert(m_marker == nullptr or m_marker  <= m_limit);
 
             // number of processed characters (p)
-            const size_t num_processed_chars = static_cast<size_t>(m_start - m_content);
+            const auto num_processed_chars = static_cast<size_t>(m_start - m_content);
             // offset for m_marker wrt. to m_start
             const auto offset_marker = (m_marker == nullptr) ? 0 : m_marker - m_start;
             // number of unprocessed characters (u)
@@ -10219,7 +11735,7 @@ basic_json_parser_66:
             if (m_stream == nullptr or m_stream->eof())
             {
                 // m_start may or may not be pointing into m_line_buffer at
-                // this point. We trust the standand library to do the right
+                // this point. We trust the standard library to do the right
                 // thing. See http://stackoverflow.com/q/28142011/266378
                 m_line_buffer.assign(m_start, m_limit);
 
@@ -10237,6 +11753,13 @@ basic_json_parser_66:
                 m_line_buffer.erase(0, num_processed_chars);
                 // read next line from input stream
                 m_line_buffer_tmp.clear();
+
+                // check if stream is still good
+                if (m_stream->fail())
+                {
+                    JSON_THROW(parse_error::create(111, 0, "bad input stream"));
+                }
+
                 std::getline(*m_stream, m_line_buffer_tmp, '\n');
 
                 // add line with newline symbol to the line buffer
@@ -10307,7 +11830,7 @@ basic_json_parser_66:
         m_start + 1 + x < m_cursor - 1 must hold to loop indefinitely. This
         can be rephrased to m_cursor - m_start - 2 > x. With the
         precondition, we x <= 0, meaning that the loop condition holds
-        indefinitly if i is always decreased. However, observe that the value
+        indefinitely if i is always decreased. However, observe that the value
         of i is strictly increasing with each iteration, as it is incremented
         by 1 in the iteration expression and never decremented inside the loop
         body. Hence, the loop condition will eventually be false which
@@ -10316,7 +11839,8 @@ basic_json_parser_66:
 
         @return string value of current token without opening and closing
         quotes
-        @throw std::out_of_range if to_unicode fails
+        @throw parse_error.102 if to_unicode fails or surrogate error
+        @throw parse_error.103 if to_unicode fails
         */
         string_t get_string() const
         {
@@ -10402,7 +11926,7 @@ basic_json_parser_66:
                                 // make sure there is a subsequent unicode
                                 if ((i + 6 >= m_limit) or * (i + 5) != '\\' or * (i + 6) != 'u')
                                 {
-                                    throw std::invalid_argument("missing low surrogate");
+                                    JSON_THROW(parse_error::create(102, get_position(), "missing low surrogate"));
                                 }
 
                                 // get code yyyy from uxxxx\uyyyy
@@ -10415,7 +11939,7 @@ basic_json_parser_66:
                             else if (codepoint >= 0xDC00 and codepoint <= 0xDFFF)
                             {
                                 // we found a lone low surrogate
-                                throw std::invalid_argument("missing high surrogate");
+                                JSON_THROW(parse_error::create(102, get_position(), "missing high surrogate"));
                             }
                             else
                             {
@@ -10433,186 +11957,245 @@ basic_json_parser_66:
             return result;
         }
 
-        /*!
-        @brief parse floating point number
 
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
+        /*!
+        @brief parse string into a built-in arithmetic type as if the current
+               locale is POSIX.
 
-        @param[in,out] endptr recieves a pointer to the first character after
-        the number
+        @note in floating-point case strtod may parse past the token's end -
+              this is not an error
 
-        @return the floating point number
+        @note any leading blanks are not handled
         */
-        long double str_to_float_t(long double* /* type */, char** endptr) const
+        struct strtonum
         {
-            return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
+          public:
+            strtonum(const char* start, const char* end)
+                : m_start(start), m_end(end)
+            {}
 
-        /*!
-        @brief parse floating point number
+            /*!
+            @return true iff parsed successfully as number of type T
 
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
+            @param[in,out] val shall contain parsed value, or undefined value
+            if could not parse
+            */
+            template<typename T, typename = typename std::enable_if<std::is_arithmetic<T>::value>::type>
+            bool to(T& val) const
+            {
+                return parse(val, std::is_integral<T>());
+            }
 
-        @param[in,out] endptr  recieves a pointer to the first character after
-        the number
+          private:
+            const char* const m_start = nullptr;
+            const char* const m_end = nullptr;
 
-        @return the floating point number
-        */
-        double str_to_float_t(double* /* type */, char** endptr) const
-        {
-            return std::strtod(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
+            // floating-point conversion
 
-        /*!
-        @brief parse floating point number
+            // overloaded wrappers for strtod/strtof/strtold
+            // that will be called from parse<floating_point_t>
+            static void strtof(float& f, const char* str, char** endptr)
+            {
+                f = std::strtof(str, endptr);
+            }
 
-        This function (and its overloads) serves to select the most approprate
-        standard floating point number parsing function based on the type
-        supplied via the first parameter.  Set this to @a
-        static_cast<number_float_t*>(nullptr).
+            static void strtof(double& f, const char* str, char** endptr)
+            {
+                f = std::strtod(str, endptr);
+            }
 
-        @param[in,out] endptr  recieves a pointer to the first character after
-        the number
+            static void strtof(long double& f, const char* str, char** endptr)
+            {
+                f = std::strtold(str, endptr);
+            }
 
-        @return the floating point number
-        */
-        float str_to_float_t(float* /* type */, char** endptr) const
-        {
-            return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
-        }
+            template<typename T>
+            bool parse(T& value, /*is_integral=*/std::false_type) const
+            {
+                // replace decimal separator with locale-specific version,
+                // when necessary; data will point to either the original
+                // string, or buf, or tempstr containing the fixed string.
+                std::string tempstr;
+                std::array<char, 64> buf;
+                const size_t len = static_cast<size_t>(m_end - m_start);
 
-        /*!
-        @brief return number value for number tokens
+                // lexer will reject empty numbers
+                assert(len > 0);
 
-        This function translates the last token into the most appropriate
-        number type (either integer, unsigned integer or floating point),
-        which is passed back to the caller via the result parameter.
+                // since dealing with strtod family of functions, we're
+                // getting the decimal point char from the C locale facilities
+                // instead of C++'s numpunct facet of the current std::locale
+                const auto loc = localeconv();
+                assert(loc != nullptr);
+                const char decimal_point_char = (loc->decimal_point == nullptr) ? '.' : loc->decimal_point[0];
 
-        This function parses the integer component up to the radix point or
-        exponent while collecting information about the 'floating point
-        representation', which it stores in the result parameter. If there is
-        no radix point or exponent, and the number can fit into a @ref
-        number_integer_t or @ref number_unsigned_t then it sets the result
-        parameter accordingly.
+                const char* data = m_start;
 
-        If the number is a floating point number the number is then parsed
-        using @a std:strtod (or @a std:strtof or @a std::strtold).
+                if (decimal_point_char != '.')
+                {
+                    const size_t ds_pos = static_cast<size_t>(std::find(m_start, m_end, '.') - m_start);
 
-        @param[out] result  @ref basic_json object to receive the number, or
-        NAN if the conversion read past the current token. The latter case
-        needs to be treated by the caller function.
-        */
-        void get_number(basic_json& result) const
-        {
-            assert(m_start != nullptr);
+                    if (ds_pos != len)
+                    {
+                        // copy the data into the local buffer or tempstr, if
+                        // buffer is too small; replace decimal separator, and
+                        // update data to point to the modified bytes
+                        if ((len + 1) < buf.size())
+                        {
+                            std::copy(m_start, m_end, buf.begin());
+                            buf[len] = 0;
+                            buf[ds_pos] = decimal_point_char;
+                            data = buf.data();
+                        }
+                        else
+                        {
+                            tempstr.assign(m_start, m_end);
+                            tempstr[ds_pos] = decimal_point_char;
+                            data = tempstr.c_str();
+                        }
+                    }
+                }
+
+                char* endptr = nullptr;
+                value = 0;
+                // this calls appropriate overload depending on T
+                strtof(value, data, &endptr);
 
-            const lexer::lexer_char_t* curptr = m_start;
+                // parsing was successful iff strtof parsed exactly the number
+                // of characters determined by the lexer (len)
+                const bool ok = (endptr == (data + len));
 
-            // accumulate the integer conversion result (unsigned for now)
-            number_unsigned_t value = 0;
+                if (ok and (value == static_cast<T>(0.0)) and (*data == '-'))
+                {
+                    // some implementations forget to negate the zero
+                    value = -0.0;
+                }
 
-            // maximum absolute value of the relevant integer type
-            number_unsigned_t max;
+                return ok;
+            }
 
-            // temporarily store the type to avoid unecessary bitfield access
-            value_t type;
+            // integral conversion
 
-            // look for sign
-            if (*curptr == '-')
+            signed long long parse_integral(char** endptr, /*is_signed*/std::true_type) const
             {
-                type = value_t::number_integer;
-                max = static_cast<uint64_t>((std::numeric_limits<number_integer_t>::max)()) + 1;
-                curptr++;
+                return std::strtoll(m_start, endptr, 10);
             }
-            else
+
+            unsigned long long parse_integral(char** endptr, /*is_signed*/std::false_type) const
+            {
+                return std::strtoull(m_start, endptr, 10);
+            }
+
+            template<typename T>
+            bool parse(T& value, /*is_integral=*/std::true_type) const
             {
-                type = value_t::number_unsigned;
-                max = static_cast<uint64_t>((std::numeric_limits<number_unsigned_t>::max)());
+                char* endptr = nullptr;
+                errno = 0; // these are thread-local
+                const auto x = parse_integral(&endptr, std::is_signed<T>());
+
+                // called right overload?
+                static_assert(std::is_signed<T>() == std::is_signed<decltype(x)>(), "");
+
+                value = static_cast<T>(x);
+
+                return (x == static_cast<decltype(x)>(value)) // x fits into destination T
+                       and (x < 0) == (value < 0)             // preserved sign
+                       //and ((x != 0) or is_integral())        // strto[u]ll did nto fail
+                       and (errno == 0)                       // strto[u]ll did not overflow
+                       and (m_start < m_end)                  // token was not empty
+                       and (endptr == m_end);                 // parsed entire token exactly
             }
+        };
+
+        /*!
+        @brief return number value for number tokens
+
+        This function translates the last token into the most appropriate
+        number type (either integer, unsigned integer or floating point),
+        which is passed back to the caller via the result parameter.
+
+        integral numbers that don't fit into the the range of the respective
+        type are parsed as number_float_t
+
+        floating-point values do not satisfy std::isfinite predicate
+        are converted to value_t::null
+
+        throws if the entire string [m_start .. m_cursor) cannot be
+        interpreted as a number
+
+        @param[out] result  @ref basic_json object to receive the number.
+        @param[in]  token   the type of the number token
+        */
+        bool get_number(basic_json& result, const token_type token) const
+        {
+            assert(m_start != nullptr);
+            assert(m_start < m_cursor);
+            assert((token == token_type::value_unsigned) or
+                   (token == token_type::value_integer) or
+                   (token == token_type::value_float));
 
-            // count the significant figures
-            for (; curptr < m_cursor; curptr++)
+            strtonum num_converter(reinterpret_cast<const char*>(m_start),
+                                   reinterpret_cast<const char*>(m_cursor));
+
+            switch (token)
             {
-                // quickly skip tests if a digit
-                if (*curptr < '0' || *curptr > '9')
+                case lexer::token_type::value_unsigned:
                 {
-                    if (*curptr == '.')
+                    number_unsigned_t val;
+                    if (num_converter.to(val))
                     {
-                        // don't count '.' but change to float
-                        type = value_t::number_float;
-                        continue;
+                        // parsing successful
+                        result.m_type = value_t::number_unsigned;
+                        result.m_value = val;
+                        return true;
                     }
-                    // assume exponent (if not then will fail parse): change to
-                    // float, stop counting and record exponent details
-                    type = value_t::number_float;
                     break;
                 }
 
-                // skip if definitely not an integer
-                if (type != value_t::number_float)
+                case lexer::token_type::value_integer:
                 {
-                    auto digit = static_cast<number_unsigned_t>(*curptr - '0');
-
-                    // overflow if value * 10 + digit > max, move terms around
-                    // to avoid overflow in intermediate values
-                    if (value > (max - digit) / 10)
-                    {
-                        // overflow
-                        type = value_t::number_float;
-                    }
-                    else
+                    number_integer_t val;
+                    if (num_converter.to(val))
                     {
-                        // no overflow
-                        value = value * 10 + digit;
+                        // parsing successful
+                        result.m_type = value_t::number_integer;
+                        result.m_value = val;
+                        return true;
                     }
+                    break;
                 }
-            }
-
-            // save the value (if not a float)
-            if (type == value_t::number_unsigned)
-            {
-                result.m_value.number_unsigned = value;
-            }
-            else if (type == value_t::number_integer)
-            {
-                // invariant: if we parsed a '-', the absolute value is between
-                // 0 (we allow -0) and max == -INT64_MIN
-                assert(value >= 0);
-                assert(value <= max);
 
-                if (value == max)
-                {
-                    // we cannot simply negate value (== max == -INT64_MIN),
-                    // see https://github.com/nlohmann/json/issues/389
-                    result.m_value.number_integer = static_cast<number_integer_t>(INT64_MIN);
-                }
-                else
+                default:
                 {
-                    // all other values can be negated safely
-                    result.m_value.number_integer = -static_cast<number_integer_t>(value);
+                    break;
                 }
             }
-            else
+
+            // parse float (either explicitly or because a previous conversion
+            // failed)
+            number_float_t val;
+            if (num_converter.to(val))
             {
-                // parse with strtod
-                result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
+                // parsing successful
+                result.m_type = value_t::number_float;
+                result.m_value = val;
 
-                // replace infinity and NAN by null
+                // throw in case of infinity or NAN
                 if (not std::isfinite(result.m_value.number_float))
                 {
-                    type = value_t::null;
-                    result.m_value = basic_json::json_value();
+                    JSON_THROW(out_of_range::create(406, "number overflow parsing '" + get_token_string() + "'"));
                 }
+
+                return true;
             }
 
-            // save the type
-            result.m_type = type;
+            // couldn't parse number in any format
+            return false;
+        }
+
+        constexpr size_t get_position() const
+        {
+            return position;
         }
 
       private:
@@ -10634,6 +12217,8 @@ basic_json_parser_66:
         const lexer_char_t* m_limit = nullptr;
         /// the last token type
         token_type last_token_type = token_type::end_of_input;
+        /// current position in the input (read bytes)
+        size_t position = 0;
     };
 
     /*!
@@ -10650,7 +12235,10 @@ basic_json_parser_66:
               m_lexer(reinterpret_cast<const typename lexer::lexer_char_t*>(buff), std::strlen(buff))
         {}
 
-        /// a parser reading from an input stream
+        /*!
+        @brief a parser reading from an input stream
+        @throw parse_error.111 if input stream is in a bad state
+        */
         parser(std::istream& is, const parser_callback_t cb = nullptr)
             : callback(cb), m_lexer(is)
         {}
@@ -10666,7 +12254,12 @@ basic_json_parser_66:
                       static_cast<size_t>(std::distance(first, last)))
         {}
 
-        /// public parser interface
+        /*!
+        @brief public parser interface
+        @throw parse_error.101 in case of an unexpected token
+        @throw parse_error.102 if to_unicode fails or surrogate error
+        @throw parse_error.103 if to_unicode fails
+        */
         basic_json parse()
         {
             // read first token
@@ -10683,7 +12276,12 @@ basic_json_parser_66:
         }
 
       private:
-        /// the actual parser
+        /*!
+        @brief the actual parser
+        @throw parse_error.101 in case of an unexpected token
+        @throw parse_error.102 if to_unicode fails or surrogate error
+        @throw parse_error.103 if to_unicode fails
+        */
         basic_json parse_internal(bool keep)
         {
             auto result = basic_json(value_t::discarded);
@@ -10856,9 +12454,11 @@ basic_json_parser_66:
                     break;
                 }
 
-                case lexer::token_type::value_number:
+                case lexer::token_type::value_unsigned:
+                case lexer::token_type::value_integer:
+                case lexer::token_type::value_float:
                 {
-                    m_lexer.get_number(result);
+                    m_lexer.get_number(result, last_token);
                     get_token();
                     break;
                 }
@@ -10884,6 +12484,9 @@ basic_json_parser_66:
             return last_token;
         }
 
+        /*!
+        @throw parse_error.101 if expected token did not occur
+        */
         void expect(typename lexer::token_type t) const
         {
             if (t != last_token)
@@ -10893,10 +12496,13 @@ basic_json_parser_66:
                               "'") :
                               lexer::token_type_name(last_token));
                 error_msg += "; expected " + lexer::token_type_name(t);
-                throw std::invalid_argument(error_msg);
+                JSON_THROW(parse_error::create(101, m_lexer.get_position(), error_msg));
             }
         }
 
+        /*!
+        @throw parse_error.101 if unexpected token occurred
+        */
         void unexpect(typename lexer::token_type t) const
         {
             if (t == last_token)
@@ -10905,7 +12511,7 @@ basic_json_parser_66:
                 error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
                               "'") :
                               lexer::token_type_name(last_token));
-                throw std::invalid_argument(error_msg);
+                JSON_THROW(parse_error::create(101, m_lexer.get_position(), error_msg));
             }
         }
 
@@ -10948,12 +12554,12 @@ basic_json_parser_66:
                       empty string is assumed which references the whole JSON
                       value
 
-        @throw std::domain_error if reference token is nonempty and does not
-        begin with a slash (`/`); example: `"JSON pointer must be empty or
-        begin with /"`
-        @throw std::domain_error if a tilde (`~`) is not followed by `0`
-        (representing `~`) or `1` (representing `/`); example: `"escape error:
-        ~ must be followed with 0 or 1"`
+        @throw parse_error.107 if the given JSON pointer @a s is nonempty and
+        does not begin with a slash (`/`); see example below
+
+        @throw parse_error.108 if a tilde (`~`) in the given JSON pointer @a s
+        is not followed by `0` (representing `~`) or `1` (representing `/`);
+        see example below
 
         @liveexample{The example shows the construction several valid JSON
         pointers as well as the exceptional behavior.,json_pointer}
@@ -10996,12 +12602,15 @@ basic_json_parser_66:
         }
 
       private:
-        /// remove and return last reference pointer
+        /*!
+        @brief remove and return last reference pointer
+        @throw out_of_range.405 if JSON pointer has no parent
+        */
         std::string pop_back()
         {
             if (is_root())
             {
-                throw std::domain_error("JSON pointer has no parent");
+                JSON_THROW(out_of_range::create(405, "JSON pointer has no parent"));
             }
 
             auto last = reference_tokens.back();
@@ -11019,7 +12628,7 @@ basic_json_parser_66:
         {
             if (is_root())
             {
-                throw std::domain_error("JSON pointer has no parent");
+                JSON_THROW(out_of_range::create(405, "JSON pointer has no parent"));
             }
 
             json_pointer result = *this;
@@ -11031,6 +12640,9 @@ basic_json_parser_66:
         @brief create and return a reference to the pointed to value
 
         @complexity Linear in the number of reference tokens.
+
+        @throw parse_error.109 if array index is not a number
+        @throw type_error.313 if value cannot be unflattened
         */
         reference get_and_create(reference j) const
         {
@@ -11067,7 +12679,14 @@ basic_json_parser_66:
                     case value_t::array:
                     {
                         // create an entry in the array
-                        result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        JSON_TRY
+                        {
+                            result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        }
+                        JSON_CATCH (std::invalid_argument&)
+                        {
+                            JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                        }
                         break;
                     }
 
@@ -11080,7 +12699,7 @@ basic_json_parser_66:
                     */
                     default:
                     {
-                        throw std::domain_error("invalid value to unflatten");
+                        JSON_THROW(type_error::create(313, "invalid value to unflatten"));
                     }
                 }
             }
@@ -11103,9 +12722,9 @@ basic_json_parser_66:
 
         @complexity Linear in the length of the JSON pointer.
 
-        @throw std::out_of_range      if the JSON pointer can not be resolved
-        @throw std::domain_error      if an array index begins with '0'
-        @throw std::invalid_argument  if an array index was not a number
+        @throw parse_error.106   if an array index begins with '0'
+        @throw parse_error.109   if an array index was not a number
+        @throw out_of_range.404  if the JSON pointer can not be resolved
         */
         reference get_unchecked(pointer ptr) const
         {
@@ -11119,7 +12738,7 @@ basic_json_parser_66:
                                                   reference_token.end(),
                                                   [](const char x)
                     {
-                        return std::isdigit(x);
+                        return (x >= '0' and x <= '9');
                     });
 
                     // change value to array for numbers or "-" or to object
@@ -11148,25 +12767,32 @@ basic_json_parser_66:
                         // error condition (cf. RFC 6901, Sect. 4)
                         if (reference_token.size() > 1 and reference_token[0] == '0')
                         {
-                            throw std::domain_error("array index must not begin with '0'");
+                            JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'"));
                         }
 
                         if (reference_token == "-")
                         {
-                            // explicityly treat "-" as index beyond the end
+                            // explicitly treat "-" as index beyond the end
                             ptr = &ptr->operator[](ptr->m_value.array->size());
                         }
                         else
                         {
                             // convert array index to number; unchecked access
-                            ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                            JSON_TRY
+                            {
+                                ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                            }
+                            JSON_CATCH (std::invalid_argument&)
+                            {
+                                JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                            }
                         }
                         break;
                     }
 
                     default:
                     {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                        JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
                     }
                 }
             }
@@ -11174,6 +12800,12 @@ basic_json_parser_66:
             return *ptr;
         }
 
+        /*!
+        @throw parse_error.106   if an array index begins with '0'
+        @throw parse_error.109   if an array index was not a number
+        @throw out_of_range.402  if the array index '-' is used
+        @throw out_of_range.404  if the JSON pointer can not be resolved
+        */
         reference get_checked(pointer ptr) const
         {
             for (const auto& reference_token : reference_tokens)
@@ -11192,25 +12824,32 @@ basic_json_parser_66:
                         if (reference_token == "-")
                         {
                             // "-" always fails the range check
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
+                            JSON_THROW(out_of_range::create(402, "array index '-' (" +
+                                                            std::to_string(ptr->m_value.array->size()) +
+                                                            ") is out of range"));
                         }
 
                         // error condition (cf. RFC 6901, Sect. 4)
                         if (reference_token.size() > 1 and reference_token[0] == '0')
                         {
-                            throw std::domain_error("array index must not begin with '0'");
+                            JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'"));
                         }
 
                         // note: at performs range check
-                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
+                        JSON_TRY
+                        {
+                            ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
+                        }
+                        JSON_CATCH (std::invalid_argument&)
+                        {
+                            JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                        }
                         break;
                     }
 
                     default:
                     {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                        JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
                     }
                 }
             }
@@ -11225,6 +12864,11 @@ basic_json_parser_66:
 
         @return const reference to the JSON value pointed to by the JSON
                 pointer
+
+        @throw parse_error.106   if an array index begins with '0'
+        @throw parse_error.109   if an array index was not a number
+        @throw out_of_range.402  if the array index '-' is used
+        @throw out_of_range.404  if the JSON pointer can not be resolved
         */
         const_reference get_unchecked(const_pointer ptr) const
         {
@@ -11244,25 +12888,32 @@ basic_json_parser_66:
                         if (reference_token == "-")
                         {
                             // "-" cannot be used for const access
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
+                            JSON_THROW(out_of_range::create(402, "array index '-' (" +
+                                                            std::to_string(ptr->m_value.array->size()) +
+                                                            ") is out of range"));
                         }
 
                         // error condition (cf. RFC 6901, Sect. 4)
                         if (reference_token.size() > 1 and reference_token[0] == '0')
                         {
-                            throw std::domain_error("array index must not begin with '0'");
+                            JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'"));
                         }
 
                         // use unchecked array access
-                        ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        JSON_TRY
+                        {
+                            ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
+                        }
+                        JSON_CATCH (std::invalid_argument&)
+                        {
+                            JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                        }
                         break;
                     }
 
                     default:
                     {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                        JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
                     }
                 }
             }
@@ -11270,6 +12921,12 @@ basic_json_parser_66:
             return *ptr;
         }
 
+        /*!
+        @throw parse_error.106   if an array index begins with '0'
+        @throw parse_error.109   if an array index was not a number
+        @throw out_of_range.402  if the array index '-' is used
+        @throw out_of_range.404  if the JSON pointer can not be resolved
+        */
         const_reference get_checked(const_pointer ptr) const
         {
             for (const auto& reference_token : reference_tokens)
@@ -11288,25 +12945,32 @@ basic_json_parser_66:
                         if (reference_token == "-")
                         {
                             // "-" always fails the range check
-                            throw std::out_of_range("array index '-' (" +
-                                                    std::to_string(ptr->m_value.array->size()) +
-                                                    ") is out of range");
+                            JSON_THROW(out_of_range::create(402, "array index '-' (" +
+                                                            std::to_string(ptr->m_value.array->size()) +
+                                                            ") is out of range"));
                         }
 
                         // error condition (cf. RFC 6901, Sect. 4)
                         if (reference_token.size() > 1 and reference_token[0] == '0')
                         {
-                            throw std::domain_error("array index must not begin with '0'");
+                            JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'"));
                         }
 
                         // note: at performs range check
-                        ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
+                        JSON_TRY
+                        {
+                            ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
+                        }
+                        JSON_CATCH (std::invalid_argument&)
+                        {
+                            JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                        }
                         break;
                     }
 
                     default:
                     {
-                        throw std::out_of_range("unresolved reference token '" + reference_token + "'");
+                        JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
                     }
                 }
             }
@@ -11314,7 +12978,15 @@ basic_json_parser_66:
             return *ptr;
         }
 
-        /// split the string input to reference tokens
+        /*!
+        @brief split the string input to reference tokens
+
+        @note This function is only called by the json_pointer constructor.
+              All exceptions below are documented there.
+
+        @throw parse_error.107  if the pointer is not empty or begins with '/'
+        @throw parse_error.108  if character '~' is not followed by '0' or '1'
+        */
         static std::vector<std::string> split(const std::string& reference_string)
         {
             std::vector<std::string> result;
@@ -11328,7 +13000,7 @@ basic_json_parser_66:
             // check if nonempty reference string begins with slash
             if (reference_string[0] != '/')
             {
-                throw std::domain_error("JSON pointer must be empty or begin with '/'");
+                JSON_THROW(parse_error::create(107, 1, "JSON pointer must be empty or begin with '/' - was: '" + reference_string + "'"));
             }
 
             // extract the reference tokens:
@@ -11336,7 +13008,7 @@ basic_json_parser_66:
             // - start: position after the previous slash
             for (
                 // search for the first slash after the first character
-                size_t slash = reference_string.find_first_of("/", 1),
+                size_t slash = reference_string.find_first_of('/', 1),
                 // set the beginning of the first reference token
                 start = 1;
                 // we can stop if start == string::npos+1 = 0
@@ -11345,16 +13017,16 @@ basic_json_parser_66:
                 // (will eventually be 0 if slash == std::string::npos)
                 start = slash + 1,
                 // find next slash
-                slash = reference_string.find_first_of("/", start))
+                slash = reference_string.find_first_of('/', start))
             {
                 // use the text between the beginning of the reference token
                 // (start) and the last slash (slash).
                 auto reference_token = reference_string.substr(start, slash - start);
 
                 // check reference tokens are properly escaped
-                for (size_t pos = reference_token.find_first_of("~");
+                for (size_t pos = reference_token.find_first_of('~');
                         pos != std::string::npos;
-                        pos = reference_token.find_first_of("~", pos + 1))
+                        pos = reference_token.find_first_of('~', pos + 1))
                 {
                     assert(reference_token[pos] == '~');
 
@@ -11363,7 +13035,7 @@ basic_json_parser_66:
                             (reference_token[pos + 1] != '0' and
                              reference_token[pos + 1] != '1'))
                     {
-                        throw std::domain_error("escape error: '~' must be followed with '0' or '1'");
+                        JSON_THROW(parse_error::create(108, 0, "escape character '~' must be followed with '0' or '1'"));
                     }
                 }
 
@@ -11375,7 +13047,6 @@ basic_json_parser_66:
             return result;
         }
 
-      private:
         /*!
         @brief replace all occurrences of a substring by another string
 
@@ -11384,7 +13055,8 @@ basic_json_parser_66:
         @param[in]     f  the substring to replace with @a t
         @param[in]     t  the string to replace @a f
 
-        @pre The search string @a f must not be empty.
+        @pre The search string @a f must not be empty. **This precondition is
+             enforced with an assertion.**
 
         @since version 2.0.0
         */
@@ -11484,12 +13156,17 @@ basic_json_parser_66:
         @param[in] value  flattened JSON
 
         @return unflattened JSON
+
+        @throw parse_error.109 if array index is not a number
+        @throw type_error.314  if value is not an object
+        @throw type_error.315  if object values are not primitive
+        @throw type_error.313  if value cannot be unflattened
         */
         static basic_json unflatten(const basic_json& value)
         {
             if (not value.is_object())
             {
-                throw std::domain_error("only objects can be unflattened");
+                JSON_THROW(type_error::create(314, "only objects can be unflattened"));
             }
 
             basic_json result;
@@ -11499,7 +13176,7 @@ basic_json_parser_66:
             {
                 if (not element.second.is_primitive())
                 {
-                    throw std::domain_error("values in object must be primitive");
+                    JSON_THROW(type_error::create(315, "values in object must be primitive"));
                 }
 
                 // assign value to reference pointed to by JSON pointer; Note
@@ -11513,7 +13190,18 @@ basic_json_parser_66:
             return result;
         }
 
-      private:
+        friend bool operator==(json_pointer const& lhs,
+                               json_pointer const& rhs) noexcept
+        {
+            return lhs.reference_tokens == rhs.reference_tokens;
+        }
+
+        friend bool operator!=(json_pointer const& lhs,
+                               json_pointer const& rhs) noexcept
+        {
+            return !(lhs == rhs);
+        }
+
         /// the reference tokens
         std::vector<std::string> reference_tokens {};
     };
@@ -11550,9 +13238,9 @@ basic_json_parser_66:
 
     @complexity Constant.
 
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.404  if the JSON pointer can not be resolved
 
     @liveexample{The behavior is shown in the example.,operatorjson_pointer}
 
@@ -11577,9 +13265,10 @@ basic_json_parser_66:
 
     @complexity Constant.
 
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.402  if the array index '-' is used
+    @throw out_of_range.404  if the JSON pointer can not be resolved
 
     @liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
 
@@ -11600,15 +13289,30 @@ basic_json_parser_66:
 
     @return reference to the element pointed to by @a ptr
 
-    @complexity Constant.
+    @throw parse_error.106 if an array index in the passed JSON pointer @a ptr
+    begins with '0'. See example below.
 
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
+    @throw parse_error.109 if an array index in the passed JSON pointer @a ptr
+    is not a number. See example below.
 
-    @liveexample{The behavior is shown in the example.,at_json_pointer}
+    @throw out_of_range.401 if an array index in the passed JSON pointer @a ptr
+    is out of range. See example below.
+
+    @throw out_of_range.402 if the array index '-' is used in the passed JSON
+    pointer @a ptr. As `at` provides checked access (and no elements are
+    implicitly inserted), the index '-' is always invalid. See example below.
+
+    @throw out_of_range.404 if the JSON pointer @a ptr can not be resolved.
+    See example below.
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
+
+    @complexity Constant.
 
     @since version 2.0.0
+
+    @liveexample{The behavior is shown in the example.,at_json_pointer}
     */
     reference at(const json_pointer& ptr)
     {
@@ -11625,15 +13329,30 @@ basic_json_parser_66:
 
     @return reference to the element pointed to by @a ptr
 
-    @complexity Constant.
+    @throw parse_error.106 if an array index in the passed JSON pointer @a ptr
+    begins with '0'. See example below.
 
-    @throw std::out_of_range      if the JSON pointer can not be resolved
-    @throw std::domain_error      if an array index begins with '0'
-    @throw std::invalid_argument  if an array index was not a number
+    @throw parse_error.109 if an array index in the passed JSON pointer @a ptr
+    is not a number. See example below.
 
-    @liveexample{The behavior is shown in the example.,at_json_pointer_const}
+    @throw out_of_range.401 if an array index in the passed JSON pointer @a ptr
+    is out of range. See example below.
+
+    @throw out_of_range.402 if the array index '-' is used in the passed JSON
+    pointer @a ptr. As `at` provides checked access (and no elements are
+    implicitly inserted), the index '-' is always invalid. See example below.
+
+    @throw out_of_range.404 if the JSON pointer @a ptr can not be resolved.
+    See example below.
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
+
+    @complexity Constant.
 
     @since version 2.0.0
+
+    @liveexample{The behavior is shown in the example.,at_json_pointer_const}
     */
     const_reference at(const json_pointer& ptr) const
     {
@@ -11648,7 +13367,7 @@ basic_json_parser_66:
     primitive. The original JSON value can be restored using the @ref
     unflatten() function.
 
-    @return an object that maps JSON pointers to primitve values
+    @return an object that maps JSON pointers to primitive values
 
     @note Empty objects and arrays are flattened to `null` and will not be
           reconstructed correctly by the @ref unflatten() function.
@@ -11689,6 +13408,9 @@ basic_json_parser_66:
 
     @complexity Linear in the size the JSON value.
 
+    @throw type_error.314  if value is not an object
+    @throw type_error.315  if object values are not primitve
+
     @liveexample{The following code shows how a flattened JSON object is
     unflattened into the original nested JSON object.,unflatten}
 
@@ -11715,7 +13437,7 @@ basic_json_parser_66:
 
     [JSON Patch](http://jsonpatch.com) defines a JSON document structure for
     expressing a sequence of operations to apply to a JSON) document. With
-    this funcion, a JSON Patch is applied to the current JSON value by
+    this function, a JSON Patch is applied to the current JSON value by
     executing all operations from the patch.
 
     @param[in] json_patch  JSON patch document
@@ -11726,12 +13448,23 @@ basic_json_parser_66:
           any case, the original value is not changed: the patch is applied
           to a copy of the value.
 
-    @throw std::out_of_range if a JSON pointer inside the patch could not
-    be resolved successfully in the current JSON value; example: `"key baz
-    not found"`
-    @throw invalid_argument if the JSON patch is malformed (e.g., mandatory
+    @throw parse_error.104 if the JSON patch does not consist of an array of
+    objects
+
+    @throw parse_error.105 if the JSON patch is malformed (e.g., mandatory
     attributes are missing); example: `"operation add must have member path"`
 
+    @throw out_of_range.401 if an array index is out of range.
+
+    @throw out_of_range.403 if a JSON pointer inside the patch could not be
+    resolved successfully in the current JSON value; example: `"key baz not
+    found"`
+
+    @throw out_of_range.405 if JSON pointer has no parent ("add", "remove",
+    "move")
+
+    @throw other_error.501 if "test" operation was unsuccessful
+
     @complexity Linear in the size of the JSON value and the length of the
     JSON patch. As usually only a fraction of the JSON value is affected by
     the patch, the complexity can usually be neglected.
@@ -11754,7 +13487,7 @@ basic_json_parser_66:
         // the valid JSON Patch operations
         enum class patch_operations {add, remove, replace, move, copy, test, invalid};
 
-        const auto get_op = [](const std::string op)
+        const auto get_op = [](const std::string & op)
         {
             if (op == "add")
             {
@@ -11828,7 +13561,7 @@ basic_json_parser_66:
                             if (static_cast<size_type>(idx) > parent.size())
                             {
                                 // avoid undefined behavior
-                                throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
+                                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
                             }
                             else
                             {
@@ -11866,7 +13599,7 @@ basic_json_parser_66:
                 }
                 else
                 {
-                    throw std::out_of_range("key '" + last_path + "' not found");
+                    JSON_THROW(out_of_range::create(403, "key '" + last_path + "' not found"));
                 }
             }
             else if (parent.is_array())
@@ -11876,14 +13609,13 @@ basic_json_parser_66:
             }
         };
 
-        // type check
+        // type check: top level value must be an array
         if (not json_patch.is_array())
         {
-            // a JSON patch must be an array of objects
-            throw std::invalid_argument("JSON patch must be an array of objects");
+            JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects"));
         }
 
-        // iterate and apply th eoperations
+        // iterate and apply the operations
         for (const auto& val : json_patch)
         {
             // wrapper to get a value for an operation
@@ -11900,23 +13632,23 @@ basic_json_parser_66:
                 // check if desired value is present
                 if (it == val.m_value.object->end())
                 {
-                    throw std::invalid_argument(error_msg + " must have member '" + member + "'");
+                    JSON_THROW(parse_error::create(105, 0, error_msg + " must have member '" + member + "'"));
                 }
 
                 // check if result is of type string
                 if (string_type and not it->second.is_string())
                 {
-                    throw std::invalid_argument(error_msg + " must have string member '" + member + "'");
+                    JSON_THROW(parse_error::create(105, 0, error_msg + " must have string member '" + member + "'"));
                 }
 
                 // no error: return value
                 return it->second;
             };
 
-            // type check
+            // type check: every element of the array must be an object
             if (not val.is_object())
             {
-                throw std::invalid_argument("JSON patch must be an array of objects");
+                JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects"));
             }
 
             // collect mandatory members
@@ -11975,13 +13707,13 @@ basic_json_parser_66:
                 case patch_operations::test:
                 {
                     bool success = false;
-                    try
+                    JSON_TRY
                     {
                         // check if "value" matches the one at "path"
                         // the "path" location must exist - use at()
                         success = (result.at(ptr) == get_value("test", "value", false));
                     }
-                    catch (std::out_of_range&)
+                    JSON_CATCH (out_of_range&)
                     {
                         // ignore out of range errors: success remains false
                     }
@@ -11989,7 +13721,7 @@ basic_json_parser_66:
                     // throw an exception if test fails
                     if (not success)
                     {
-                        throw std::domain_error("unsuccessful: " + val.dump());
+                        JSON_THROW(other_error::create(501, "unsuccessful: " + val.dump()));
                     }
 
                     break;
@@ -11999,7 +13731,7 @@ basic_json_parser_66:
                 {
                     // op must be "add", "remove", "replace", "move", "copy", or
                     // "test"
-                    throw std::invalid_argument("operation value '" + op + "' is invalid");
+                    JSON_THROW(parse_error::create(105, 0, "operation value '" + op + "' is invalid"));
                 }
             }
         }
@@ -12022,8 +13754,8 @@ basic_json_parser_66:
     @note Currently, only `remove`, `add`, and `replace` operations are
           generated.
 
-    @param[in] source  JSON value to copare from
-    @param[in] target  JSON value to copare against
+    @param[in] source  JSON value to compare from
+    @param[in] target  JSON value to compare against
     @param[in] path    helper value to create JSON pointers
 
     @return a JSON patch to convert the @a source to @a target
@@ -12174,7 +13906,6 @@ basic_json_parser_66:
     /// @}
 };
 
-
 /////////////
 // presets //
 /////////////
@@ -12188,7 +13919,7 @@ uses the standard template types.
 @since version 1.0.0
 */
 using json = basic_json<>;
-}
+} // namespace nlohmann
 
 
 ///////////////////////
@@ -12229,7 +13960,23 @@ struct hash<nlohmann::json>
         return h(j.dump());
     }
 };
-}
+
+/// specialization for std::less<value_t>
+template <>
+struct less<::nlohmann::detail::value_t>
+{
+    /*!
+    @brief compare two value_t enum values
+    @since version 3.0.0
+    */
+    bool operator()(nlohmann::detail::value_t lhs,
+                    nlohmann::detail::value_t rhs) const noexcept
+    {
+        return nlohmann::detail::operator<(lhs, rhs);
+    }
+};
+
+} // namespace std
 
 /*!
 @brief user-defined string literal for JSON values
@@ -12271,5 +14018,14 @@ inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std
 #if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
     #pragma GCC diagnostic pop
 #endif
+#if defined(__clang__)
+    #pragma GCC diagnostic pop
+#endif
+
+// clean up
+#undef JSON_CATCH
+#undef JSON_THROW
+#undef JSON_TRY
+#undef JSON_DEPRECATED
 
 #endif
diff --git a/make-linux.mk b/make-linux.mk
index 811d4a6e..5fb489bb 100644
--- a/make-linux.mk
+++ b/make-linux.mk
@@ -8,7 +8,7 @@ ifeq ($(origin CXX),default)
 endif
 
 INCLUDES?=
-DEFS?=-D_FORTIFY_SOURCE=2
+DEFS?=
 LDLIBS?=
 DESTDIR?=
 
@@ -55,14 +55,15 @@ endif
 
 ifeq ($(ZT_DEBUG),1)
 	override DEFS+=-DZT_TRACE
-	override CFLAGS+=-Wall -g -O -pthread $(INCLUDES) $(DEFS)
-	override CXXFLAGS+=-Wall -g -O -std=c++11 -pthread $(INCLUDES) $(DEFS)
+	override CFLAGS+=-Wall -g -pthread $(INCLUDES) $(DEFS)
+	override CXXFLAGS+=-Wall -g -std=c++11 -pthread $(INCLUDES) $(DEFS)
 	override LDFLAGS+=
 	STRIP?=echo
 	# The following line enables optimization for the crypto code, since
 	# C25519 in particular is almost UNUSABLE in -O0 even on a 3ghz box!
-node/Salsa20.o node/SHA512.o node/C25519.o node/Poly1305.o: CFLAGS = -Wall -O2 -g -pthread $(INCLUDES) $(DEFS)
+node/Salsa20.o node/SHA512.o node/C25519.o node/Poly1305.o: CXXFLAGS=-Wall -O2 -g -pthread $(INCLUDES) $(DEFS)
 else
+	override DEFS+=-D_FORTIFY_SOURCE=2
 	CFLAGS?=-O3 -fstack-protector
 	override CFLAGS+=-Wall -fPIE -pthread $(INCLUDES) -DNDEBUG $(DEFS)
 	CXXFLAGS?=-O3 -fstack-protector
diff --git a/node/CertificateOfOwnership.hpp b/node/CertificateOfOwnership.hpp
index 93be64dd..f01da38e 100644
--- a/node/CertificateOfOwnership.hpp
+++ b/node/CertificateOfOwnership.hpp
@@ -72,6 +72,8 @@ public:
 		_thingCount(0),
 		_issuedTo(issuedTo)
 	{
+		memset(_thingTypes,0,sizeof(_thingTypes));
+		memset(_thingValues,0,sizeof(_thingValues));
 	}
 
 	inline uint64_t networkId() const { return _networkId; }
diff --git a/root-watcher/schema.sql b/root-watcher/schema.sql
index bdb3a1cf..ade0fa3e 100644
--- a/root-watcher/schema.sql
+++ b/root-watcher/schema.sql
@@ -1,7 +1,6 @@
 /* Schema for ZeroTier root watcher log database */
 
-/* If you cluster this DB using any PG clustering scheme that uses logs, you must remove UNLOGGED here! */
-CREATE UNLOGGED TABLE "Peer"
+CREATE TABLE "Peer"
 (
 	"ztAddress" BIGINT NOT NULL,
 	"timestamp" BIGINT NOT NULL,
diff --git a/selftest.cpp b/selftest.cpp
index 33e65f2c..e23afd6e 100644
--- a/selftest.cpp
+++ b/selftest.cpp
@@ -49,7 +49,6 @@
 
 #include "osdep/OSUtils.hpp"
 #include "osdep/Phy.hpp"
-#include "osdep/Http.hpp"
 #include "osdep/PortMapper.hpp"
 #include "osdep/Thread.hpp"
 
@@ -1019,51 +1018,6 @@ static int testPhy()
 	return 0;
 }
 
-/*
-static int testHttp()
-{
-	std::map<std::string,std::string> requestHeaders,responseHeaders;
-	std::string responseBody;
-
-	InetAddress downloadZerotierDotCom;
-	std::vector<InetAddress> rr(OSUtils::resolve("download.zerotier.com"));
-	if (rr.empty()) {
-		std::cout << "[http] Resolve of download.zerotier.com failed, skipping." << std::endl;
-		return 0;
-	} else {
-		for(std::vector<InetAddress>::iterator r(rr.begin());r!=rr.end();++r) {
-			std::cout << "[http] download.zerotier.com: " << r->toString() << std::endl;
-			if (r->isV4())
-				downloadZerotierDotCom = *r;
-		}
-	}
-	downloadZerotierDotCom.setPort(80);
-
-	std::cout << "[http] GET http://download.zerotier.com/dev/1k @" << downloadZerotierDotCom.toString() << " ... "; std::cout.flush();
-	requestHeaders["Host"] = "download.zerotier.com";
-	unsigned int sc = Http::GET(1024 * 1024 * 16,60000,reinterpret_cast<const struct sockaddr *>(&downloadZerotierDotCom),"/dev/1k",requestHeaders,responseHeaders,responseBody);
-	std::cout << sc << " " << responseBody.length() << " bytes ";
-	if (sc == 0)
-		std::cout << "ERROR: " << responseBody << std::endl;
-	else std::cout << "DONE" << std::endl;
-
-	std::cout << "[http] GET http://download.zerotier.com/dev/4m @" << downloadZerotierDotCom.toString() << " ... "; std::cout.flush();
-	requestHeaders["Host"] = "download.zerotier.com";
-	sc = Http::GET(1024 * 1024 * 16,60000,reinterpret_cast<const struct sockaddr *>(&downloadZerotierDotCom),"/dev/4m",requestHeaders,responseHeaders,responseBody);
-	std::cout << sc << " " << responseBody.length() << " bytes ";
-	if (sc == 0)
-		std::cout << "ERROR: " << responseBody << std::endl;
-	else std::cout << "DONE" << std::endl;
-
-	downloadZerotierDotCom = InetAddress("1.0.0.1/1234");
-	std::cout << "[http] GET @" << downloadZerotierDotCom.toString() << " ... "; std::cout.flush();
-	sc = Http::GET(1024 * 1024 * 16,2500,reinterpret_cast<const struct sockaddr *>(&downloadZerotierDotCom),"/dev/4m",requestHeaders,responseHeaders,responseBody);
-	std::cout << sc << " (should be 0, time out)" << std::endl;
-
-	return 0;
-}
-*/
-
 #ifdef __WINDOWS__
 int __cdecl _tmain(int argc, _TCHAR* argv[])
 #else
@@ -1127,7 +1081,6 @@ int main(int argc,char **argv)
 	r |= testIdentity();
 	r |= testCertificate();
 	r |= testPhy();
-	//r |= testHttp();
 	//*/
 
 	if (r)
-- 
cgit v1.2.3


From fe1fa20c6c8c83762caba1056bcceb207d531a22 Mon Sep 17 00:00:00 2001
From: Adam Ierymenko <adam.ierymenko@gmail.com>
Date: Thu, 1 Feb 2018 12:46:35 -0800
Subject: Fix build on Intel C/C++ Compiler for Linux.

---
 ext/json/README.md |   148 +-
 ext/json/json.hpp  | 21083 ++++++++++++++++++++++++++-------------------------
 make-linux.mk      |     2 +-
 node/Hashtable.hpp |     2 +-
 node/Path.hpp      |     2 +-
 node/Utils.hpp     |     9 +-
 osdep/Phy.hpp      |     4 +-
 7 files changed, 11081 insertions(+), 10169 deletions(-)

(limited to 'ext/json/json.hpp')

diff --git a/ext/json/README.md b/ext/json/README.md
index fc6dde9b..256409e3 100644
--- a/ext/json/README.md
+++ b/ext/json/README.md
@@ -5,11 +5,12 @@
 [![Coverage Status](https://img.shields.io/coveralls/nlohmann/json.svg)](https://coveralls.io/r/nlohmann/json)
 [![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
 [![Codacy Badge](https://api.codacy.com/project/badge/Grade/f3732b3327e34358a0e9d1fe9f661f08)](https://www.codacy.com/app/nlohmann/json?utm_source=github.com&amp;utm_medium=referral&amp;utm_content=nlohmann/json&amp;utm_campaign=Badge_Grade)
-[![Try online](https://img.shields.io/badge/try-online-blue.svg)](http://melpon.org/wandbox/permlink/nv9fOg0XVVhWmFFy)
+[![Try online](https://img.shields.io/badge/try-online-blue.svg)](https://wandbox.org/permlink/Op57X0V7fTf2tdwl)
 [![Documentation](https://img.shields.io/badge/docs-doxygen-blue.svg)](http://nlohmann.github.io/json)
 [![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
 [![Github Releases](https://img.shields.io/github/release/nlohmann/json.svg)](https://github.com/nlohmann/json/releases)
 [![Github Issues](https://img.shields.io/github/issues/nlohmann/json.svg)](http://github.com/nlohmann/json/issues)
+[![Average time to resolve an issue](http://isitmaintained.com/badge/resolution/nlohmann/json.svg)](http://isitmaintained.com/project/nlohmann/json "Average time to resolve an issue")
 [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/289/badge)](https://bestpractices.coreinfrastructure.org/projects/289)
 
 - [Design goals](#design-goals)
@@ -25,6 +26,7 @@
   - [Binary formats (CBOR and MessagePack)](#binary-formats-cbor-and-messagepack)
 - [Supported compilers](#supported-compilers)
 - [License](#license)
+- [Contact](#contact)
 - [Thanks](#thanks)
 - [Used third-party tools](#used-third-party-tools)
 - [Projects using JSON for Modern C++](#projects-using-json-for-modern-c)
@@ -65,7 +67,13 @@ to the files you want to use JSON objects. That's it. Do not forget to set the n
 
 :beer: If you are using OS X and [Homebrew](http://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann_json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann_json --HEAD`.
 
-:warning: [Version 3.0.0](https://github.com/nlohmann/json/wiki/Road-toward-3.0.0) is currently under development. Branch `develop` is used for the ongoing work and is probably **unstable**. Please use the `master` branch for the last stable version 2.1.1.
+If you are using the [Meson Build System](http://mesonbuild.com), then you can wrap this repo as a subproject.
+
+If you are using [Conan](https://www.conan.io/) to manage your dependencies, merely add `jsonformoderncpp/x.y.z@vthiery/stable` to your `conanfile.py`'s requires, where `x.y.z` is the release version you want to use. Please file issues [here](https://github.com/vthiery/conan-jsonformoderncpp/issues) if you experience problems with the packages.
+
+If you are using [hunter](https://github.com/ruslo/hunter/) on your project for external dependencies, then you can use the [nlohmann_json package](https://docs.hunter.sh/en/latest/packages/pkg/nlohmann_json.html). Please see the hunter project for any issues regarding the packaging.
+
+If you are using [vcpkg](https://github.com/Microsoft/vcpkg/) on your project for external dependencies, then you can use the [nlohmann-json package](https://github.com/Microsoft/vcpkg/tree/master/ports/nlohmann-json). Please see the vcpkg project for any issues regarding the packaging.
 
 
 ## Examples
@@ -150,7 +158,7 @@ json empty_object_implicit = json({});
 json empty_object_explicit = json::object();
 
 // a way to express an _array_ of key/value pairs [["currency", "USD"], ["value", 42.99]]
-json array_not_object = { json::array({"currency", "USD"}), json::array({"value", 42.99}) };
+json array_not_object = json::array({ {"currency", "USD"}, {"value", 42.99} });
 ```
 
 
@@ -197,6 +205,29 @@ std::cout << j.dump(4) << std::endl;
 // }
 ```
 
+Note the difference between serialization and assignment:
+
+```cpp
+// store a string in a JSON value
+json j_string = "this is a string";
+
+// retrieve the string value (implicit JSON to std::string conversion)
+std::string cpp_string = j_string;
+// retrieve the string value (explicit JSON to std::string conversion)
+auto cpp_string2 = j_string.get<std::string>();
+
+// retrieve the serialized value (explicit JSON serialization)
+std::string serialized_string = j_string.dump();
+
+// output of original string
+std::cout << cpp_string << " == " << cpp_string2 << " == " << j_string.get<std::string>() << '\n';
+// output of serialized value
+std::cout << j_string << " == " << serialized_string << std::endl;
+```
+
+`.dump()` always returns the serialized value, and `.get<std::string>()` returns the originally stored string value.
+
+
 #### To/from streams (e.g. files, string streams)
 
 You can also use streams to serialize and deserialize:
@@ -321,7 +352,7 @@ o.erase("foo");
 
 ### Conversion from STL containers
 
-Any sequence container (`std::array`, `std::vector`, `std::deque`, `std::forward_list`, `std::list`) whose values can be used to construct JSON types (e.g., integers, floating point numbers, Booleans, string types, or again STL containers described in this section) can be used to create a JSON array. The same holds for similar associative containers (`std::set`, `std::multiset`, `std::unordered_set`, `std::unordered_multiset`), but in these cases the order of the elements of the array depends how the elements are ordered in the respective STL container.
+Any sequence container (`std::array`, `std::vector`, `std::deque`, `std::forward_list`, `std::list`) whose values can be used to construct JSON types (e.g., integers, floating point numbers, Booleans, string types, or again STL containers described in this section) can be used to create a JSON array. The same holds for similar associative containers (`std::set`, `std::multiset`, `std::unordered_set`, `std::unordered_multiset`), but in these cases the order of the elements of the array depends on how the elements are ordered in the respective STL container.
 
 ```cpp
 std::vector<int> c_vector {1, 2, 3, 4};
@@ -361,7 +392,7 @@ json j_umset(c_umset); // both entries for "one" are used
 // maybe ["one", "two", "one", "four"]
 ```
 
-Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON types (see examples above) can be used to to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
+Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON types (see examples above) can be used to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
 
 ```cpp
 std::map<std::string, int> c_map { {"one", 1}, {"two", 2}, {"three", 3} };
@@ -531,7 +562,11 @@ Some important things:
 
 * Those methods **MUST** be in your type's namespace (which can be the global namespace), or the library will not be able to locate them (in this example, they are in namespace `ns`, where `person` is defined).
 * When using `get<your_type>()`, `your_type` **MUST** be [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible). (There is a way to bypass this requirement described later.)
-* In function `from_json`, use function [`at()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a93403e803947b86f4da2d1fb3345cf2c.html#a93403e803947b86f4da2d1fb3345cf2c) to access the object values rather than `operator[]`. In case a key does not exists, `at` throws an exception that you can handle, whereas `operator[]` exhibits undefined behavior.
+* In function `from_json`, use function [`at()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a93403e803947b86f4da2d1fb3345cf2c.html#a93403e803947b86f4da2d1fb3345cf2c) to access the object values rather than `operator[]`. In case a key does not exist, `at` throws an exception that you can handle, whereas `operator[]` exhibits undefined behavior.
+* In case your type contains several `operator=` definitions, code like `your_variable = your_json;` [may not compile](https://github.com/nlohmann/json/issues/667). You need to write `your_variable = your_json.get<decltype your_variable>();` instead.
+* You do not need to add serializers or deserializers for STL types like `std::vector`: the library already implements these.
+* Be careful with the definition order of the `from_json`/`to_json` functions: If a type `B` has a member of type `A`, you **MUST** define `to_json(A)` before `to_json(B)`. Look at [issue 561](https://github.com/nlohmann/json/issues/561) for more details.
+
 
 #### How do I convert third-party types?
 
@@ -702,12 +737,13 @@ json j_from_msgpack = json::from_msgpack(v_msgpack);
 
 ## Supported compilers
 
-Though it's 2016 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
+Though it's 2017 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
 
-- GCC 4.9 - 6.0 (and possibly later)
-- Clang 3.4 - 3.9 (and possibly later)
+- GCC 4.9 - 7.2 (and possibly later)
+- Clang 3.4 - 5.0 (and possibly later)
+- Intel C++ Compiler 17.0.2 (and possibly later)
 - Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
-- Microsoft Visual C++ 2017 / Build Tools 15.1.548.43366 (and possibly later)
+- Microsoft Visual C++ 2017 / Build Tools 15.5.180.51428 (and possibly later)
 
 I would be happy to learn about other compilers/versions.
 
@@ -730,24 +766,28 @@ The following compilers are currently used in continuous integration at [Travis]
 
 | Compiler        | Operating System             | Version String |
 |-----------------|------------------------------|----------------|
-| GCC 4.9.3       | Ubuntu 14.04.4 LTS           | g++-4.9 (Ubuntu 4.9.3-8ubuntu2~14.04) 4.9.3 |
-| GCC 5.3.0       | Ubuntu 14.04.4 LTS           | g++-5 (Ubuntu 5.3.0-3ubuntu1~14.04) 5.3.0 20151204 |
-| GCC 6.1.1       | Ubuntu 14.04.4 LTS           | g++-6 (Ubuntu 6.1.1-3ubuntu11~14.04.1) 6.1.1 20160511 |
-| Clang 3.6.0     | Ubuntu 14.04.4 LTS           | clang version 3.6.0 (tags/RELEASE_360/final) |
-| Clang 3.6.1     | Ubuntu 14.04.4 LTS           | clang version 3.6.1 (tags/RELEASE_361/final) |
-| Clang 3.6.2     | Ubuntu 14.04.4 LTS           | clang version 3.6.2 (tags/RELEASE_362/final) |
-| Clang 3.7.0     | Ubuntu 14.04.4 LTS           | clang version 3.7.0 (tags/RELEASE_370/final) |
-| Clang 3.7.1     | Ubuntu 14.04.4 LTS           | clang version 3.7.1 (tags/RELEASE_371/final) |
-| Clang 3.8.0     | Ubuntu 14.04.4 LTS           | clang version 3.8.0 (tags/RELEASE_380/final) |
-| Clang 3.8.1     | Ubuntu 14.04.4 LTS           | clang version 3.8.1 (tags/RELEASE_381/final) |
+| GCC 4.9.4       | Ubuntu 14.04.5 LTS           | g++-4.9 (Ubuntu 4.9.4-2ubuntu1~14.04.1) 4.9.4 |
+| GCC 5.4.1       | Ubuntu 14.04.5 LTS           | g++-5 (Ubuntu 5.4.1-2ubuntu1~14.04) 5.4.1 20160904 |
+| GCC 6.3.0       | Ubuntu 14.04.5 LTS           | g++-6 (Ubuntu/Linaro 6.3.0-18ubuntu2~14.04) 6.3.0 20170519 |
+| GCC 7.1.0       | Ubuntu 14.04.5 LTS           | g++-7 (Ubuntu 7.1.0-5ubuntu2~14.04) 7.1.0
+| Clang 3.5.0     | Ubuntu 14.04.5 LTS           | clang version 3.5.0-4ubuntu2~trusty2 (tags/RELEASE_350/final) |
+| Clang 3.6.2     | Ubuntu 14.04.5 LTS           | clang version 3.6.2-svn240577-1~exp1 (branches/release_36) |
+| Clang 3.7.1     | Ubuntu 14.04.5 LTS           | clang version 3.7.1-svn253571-1~exp1 (branches/release_37) |
+| Clang 3.8.0     | Ubuntu 14.04.5 LTS           | clang version 3.8.0-2ubuntu3~trusty5 (tags/RELEASE_380/final) |
+| Clang 3.9.1     | Ubuntu 14.04.5 LTS           | clang version 3.9.1-4ubuntu3~14.04.2 (tags/RELEASE_391/rc2) |
+| Clang 4.0.1     | Ubuntu 14.04.5 LTS           | clang version 4.0.1-svn305264-1~exp1 (branches/release_40) |
+| Clang 5.0.0     | Ubuntu 14.04.5 LTS           | clang version 5.0.0-svn310902-1~exp1 (branches/release_50) |
 | Clang Xcode 6.4 | Darwin Kernel Version 14.3.0 (OSX 10.10.3) | Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn) |
 | Clang Xcode 7.3 | Darwin Kernel Version 15.0.0 (OSX 10.10.5) | Apple LLVM version 7.3.0 (clang-703.0.29) |
 | Clang Xcode 8.0 | Darwin Kernel Version 15.6.0 | Apple LLVM version 8.0.0 (clang-800.0.38) |
 | Clang Xcode 8.1 | Darwin Kernel Version 16.1.0 (macOS 10.12.1) | Apple LLVM version 8.0.0 (clang-800.0.42.1) |
 | Clang Xcode 8.2 | Darwin Kernel Version 16.1.0 (macOS 10.12.1) | Apple LLVM version 8.0.0 (clang-800.0.42.1) |
 | Clang Xcode 8.3 | Darwin Kernel Version 16.5.0 (macOS 10.12.4) | Apple LLVM version 8.1.0 (clang-802.0.38) |
-| Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25123.0 | 
-| Visual Studio 2017 | Windows Server 2016 | Microsoft (R) Build Engine version 15.1.548.43366 |
+| Clang Xcode 9.0 | Darwin Kernel Version 16.7.0 (macOS 10.12.6) | Apple LLVM version 9.0.0 (clang-900.0.37) |
+| Clang Xcode 9.1 | Darwin Kernel Version 16.7.0 (macOS 10.12.6) | Apple LLVM version 9.0.0 (clang-900.0.38) |
+| Clang Xcode 9.2 | Darwin Kernel Version 16.7.0 (macOS 10.12.6) | Apple LLVM version 8.1.0 (clang-900.0.39.2) |
+| Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25420.1, MSVC 19.0.24215.1 | 
+| Visual Studio 2017 | Windows Server 2016 | Microsoft (R) Build Engine version 15.5.180.51428, MSVC 19.12.25830.2 |
 
 ## License
 
@@ -763,11 +803,23 @@ The above copyright notice and this permission notice shall be included in all c
 
 THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+* * *
+
+The class contains the UTF-8 Decoder from Bjoern Hoehrmann which is licensed under the [MIT License](http://opensource.org/licenses/MIT) (see above). Copyright &copy; 2008-2009 [Björn Hoehrmann](http://bjoern.hoehrmann.de/) <bjoern@hoehrmann.de>
+
+## Contact
+
+If you have questions regarding the library, I would like to invite you to [open an issue at Github](https://github.com/nlohmann/json/issues/new). Please describe your request, problem, or question as detailed as possible, and also mention the version of the library you are using as well as the version of your compiler and operating system. Opening an issue at Github allows other users and contributors to this library to collaborate. For instance, I have little experience with MSVC, and most issues in this regard have been solved by a growing community. If you have a look at the [closed issues](https://github.com/nlohmann/json/issues?q=is%3Aissue+is%3Aclosed), you will see that we react quite timely in most cases.
+
+Only if your request would contain confidential information, please [send me an email](mailto:mail@nlohmann.me). For encrypted messages, please use [this key](https://keybase.io/nlohmann/pgp_keys.asc).
+
 
 ## Thanks
 
 I deeply appreciate the help of the following people.
 
+![Contributors](https://raw.githubusercontent.com/nlohmann/json/develop/doc/avatars.png)
+
 - [Teemperor](https://github.com/Teemperor) implemented CMake support and lcov integration, realized escape and Unicode handling in the string parser, and fixed the JSON serialization.
 - [elliotgoodrich](https://github.com/elliotgoodrich) fixed an issue with double deletion in the iterator classes.
 - [kirkshoop](https://github.com/kirkshoop) made the iterators of the class composable to other libraries.
@@ -836,6 +888,35 @@ I deeply appreciate the help of the following people.
 - [ftillier](https://github.com/ftillier) fixed a compiler warning.
 - [tinloaf](https://github.com/tinloaf) made sure all pushed warnings are properly popped.
 - [Fytch](https://github.com/Fytch) found a bug in the documentation.
+- [Jay Sistar](https://github.com/Type1J) implemented a Meson build description.
+- [Henry Lee](https://github.com/HenryRLee) fixed a warning in ICC and improved the iterator implementation.
+- [Vincent Thiery](https://github.com/vthiery) maintains a package for the Conan package manager.
+- [Steffen](https://github.com/koemeet) fixed a potential issue with MSVC and `std::min`.
+- [Mike Tzou](https://github.com/Chocobo1) fixed some typos.
+- [amrcode](https://github.com/amrcode) noted a missleading documentation about comparison of floats.
+- [Oleg Endo](https://github.com/olegendo) reduced the memory consumption by replacing `<iostream>` with `<iosfwd>`.
+- [dan-42](https://github.com/dan-42) cleaned up the CMake files to simplify including/reusing of the library.
+- [Nikita Ofitserov](https://github.com/himikof) allowed for moving values from initializer lists.
+- [Greg Hurrell](https://github.com/wincent) fixed a typo.
+- [Dmitry Kukovinets](https://github.com/DmitryKuk) fixed a typo.
+- [kbthomp1](https://github.com/kbthomp1) fixed an issue related to the Intel OSX compiler.
+- [Markus Werle](https://github.com/daixtrose) fixed a typo.
+- [WebProdPP](https://github.com/WebProdPP) fixed a subtle error in a precondition check.
+- [Alex](https://github.com/leha-bot) noted an error in a code sample.
+- [Tom de Geus](https://github.com/tdegeus) reported some warnings with ICC and helped fixing them.
+- [Perry Kundert](https://github.com/pjkundert) simplified reading from input streams.
+- [Sonu Lohani](https://github.com/sonulohani) fixed a small compilation error.
+- [Jamie Seward](https://github.com/jseward) fixed all MSVC warnings.
+- [Nate Vargas](https://github.com/eld00d) added a Doxygen tag file.
+- [pvleuven](https://github.com/pvleuven) helped fixing a warning in ICC.
+- [Pavel](https://github.com/crea7or) helped fixing some warnings in MSVC.
+- [Jamie Seward](https://github.com/jseward) avoided unneccessary string copies in `find()` and `count()`.
+- [Mitja](https://github.com/Itja) fixed some typos.
+- [Jorrit Wronski](https://github.com/jowr) updated the Hunter package links.
+- [Matthias Möller](https://github.com/TinyTinni) added a `.natvis` for the MSVC debug view.
+- [bogemic](https://github.com/bogemic) fixed some C++17 deprecation warnings.
+- [Eren Okka](https://github.com/erengy) fixed some MSVC warnings.
+
 
 Thanks a lot for helping out! Please [let me know](mailto:mail@nlohmann.me) if I forgot someone.
 
@@ -852,7 +933,6 @@ The library itself contains of a single header file licensed under the MIT licen
 - [**Clang**](http://clang.llvm.org) for compilation with code sanitizers
 - [**Cmake**](https://cmake.org) for build automation
 - [**Codacity**](https://www.codacy.com) for further [code analysis](https://www.codacy.com/app/nlohmann/json)
-- [**cotire**](https://github.com/sakra/cotire) to speed of compilation
 - [**Coveralls**](https://coveralls.io) to measure [code coverage](https://coveralls.io/github/nlohmann/json)
 - [**Coverity Scan**](https://scan.coverity.com) for [static analysis](https://scan.coverity.com/projects/nlohmann-json)
 - [**cppcheck**](http://cppcheck.sourceforge.net) for static analysis
@@ -862,11 +942,11 @@ The library itself contains of a single header file licensed under the MIT licen
 - [**Github Changelog Generator**](https://github.com/skywinder/github-changelog-generator) to generate the [ChangeLog](https://github.com/nlohmann/json/blob/develop/ChangeLog.md)
 - [**libFuzzer**](http://llvm.org/docs/LibFuzzer.html) to implement fuzz testing for OSS-Fuzz
 - [**OSS-Fuzz**](https://github.com/google/oss-fuzz) for continuous fuzz testing of the library
-- [**re2c**](http://re2c.org) to generate an automaton for the lexical analysis
+- [**Probot**](https://probot.github.io) for automating maintainer tasks such as closing stale issues, requesting missing information, or detecting toxic comments.
 - [**send_to_wandbox**](https://github.com/nlohmann/json/blob/develop/doc/scripts/send_to_wandbox.py) to send code examples to [Wandbox](http://melpon.org/wandbox)
 - [**Travis**](https://travis-ci.org) for [continuous integration](https://travis-ci.org/nlohmann/json) on Linux and macOS
 - [**Valgrind**](http://valgrind.org) to check for correct memory management
-- [**Wandbox**](http://melpon.org/wandbox) for [online examples](http://melpon.org/wandbox/permlink/4NEU6ZZMoM9lpIex)
+- [**Wandbox**](http://melpon.org/wandbox) for [online examples](https://wandbox.org/permlink/Op57X0V7fTf2tdwl)
 
 
 ## Projects using JSON for Modern C++
@@ -880,35 +960,25 @@ The library is currently used in Apple macOS Sierra and iOS 10. I am not sure wh
 - As the exact type of a number is not defined in the [JSON specification](http://rfc7159.net/rfc7159), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
 - The library supports **Unicode input** as follows:
   - Only **UTF-8** encoded input is supported which is the default encoding for JSON according to [RFC 7159](http://rfc7159.net/rfc7159#rfc.section.8.1).
-  - Other encodings such as Latin-1, UTF-16, or UTF-32 are not supported and will yield parse errors.
+  - Other encodings such as Latin-1, UTF-16, or UTF-32 are not supported and will yield parse or serialization errors.
   - [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1) will not be replaced by the library.
   - Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
   - The strings stored in the library are UTF-8 encoded. When using the default string type (`std::string`), note that its length/size functions return the number of stored bytes rather than the number of characters or glyphs.
 - The code can be compiled without C++ **runtime type identification** features; that is, you can use the `-fno-rtti` compiler flag.
 - **Exceptions** are used widely within the library. They can, however, be switched off with either using the compiler flag `-fno-exceptions` or by defining the symbol `JSON_NOEXCEPTION`. In this case, exceptions are replaced by an `abort()` call.
-- By default, the library does not preserve the **insertion order of object elements**. This is standards-compliant, as the [JSON standard](https://tools.ietf.org/html/rfc7159.html) defines objects as "an unordered collection of zero or more name/value pairs". If you do want to preserve the insertion order, you can specialize the object type with containers like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map).
+- By default, the library does not preserve the **insertion order of object elements**. This is standards-compliant, as the [JSON standard](https://tools.ietf.org/html/rfc7159.html) defines objects as "an unordered collection of zero or more name/value pairs". If you do want to preserve the insertion order, you can specialize the object type with containers like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) ([integration](https://github.com/nlohmann/json/issues/546#issuecomment-304447518)) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).
 
 
 ## Execute unit tests
 
 To compile and run the tests, you need to execute
 
-```sh
-$ make json_unit -Ctest
-$ ./test/json_unit "*"
-
-===============================================================================
-All tests passed (11203022 assertions in 48 test cases)
-```
-
-Alternatively, you can use [CMake](https://cmake.org) and run
-
 ```sh
 $ mkdir build
 $ cd build
 $ cmake ..
-$ make
-$ ctest
+$ cmake --build .
+$ ctest --output-on-failure
 ```
 
 For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).
diff --git a/ext/json/json.hpp b/ext/json/json.hpp
index 8a8b876a..5b0b0ea5 100644
--- a/ext/json/json.hpp
+++ b/ext/json/json.hpp
@@ -1,7 +1,7 @@
 /*
     __ _____ _____ _____
  __|  |   __|     |   | |  JSON for Modern C++
-|  |  |__   |  |  | | | |  version 2.1.1
+|  |  |__   |  |  | | | |  version 3.0.1
 |_____|_____|_____|_|___|  https://github.com/nlohmann/json
 
 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
@@ -29,7 +29,7 @@ SOFTWARE.
 #ifndef NLOHMANN_JSON_HPP
 #define NLOHMANN_JSON_HPP
 
-#include <algorithm> // all_of, copy, fill, find, for_each, none_of, remove, reverse, transform
+#include <algorithm> // all_of, copy, fill, find, for_each, generate_n, none_of, remove, reverse, transform
 #include <array> // array
 #include <cassert> // assert
 #include <ciso646> // and, not, or
@@ -38,11 +38,12 @@ SOFTWARE.
 #include <cstddef> // nullptr_t, ptrdiff_t, size_t
 #include <cstdint> // int64_t, uint64_t
 #include <cstdlib> // abort, strtod, strtof, strtold, strtoul, strtoll, strtoull
-#include <cstring> // strlen
+#include <cstring> // memcpy, strlen
 #include <forward_list> // forward_list
 #include <functional> // function, hash, less
 #include <initializer_list> // initializer_list
-#include <iostream> // istream, ostream
+#include <iomanip> // hex
+#include <iosfwd>   // istream, ostream
 #include <iterator> // advance, begin, back_inserter, bidirectional_iterator_tag, distance, end, inserter, iterator, iterator_traits, next, random_access_iterator_tag, reverse_iterator
 #include <limits> // numeric_limits
 #include <locale> // locale
@@ -53,6 +54,7 @@ SOFTWARE.
 #include <string> // getline, stoi, string, to_string
 #include <type_traits> // add_pointer, conditional, decay, enable_if, false_type, integral_constant, is_arithmetic, is_base_of, is_const, is_constructible, is_convertible, is_default_constructible, is_enum, is_floating_point, is_integral, is_nothrow_move_assignable, is_nothrow_move_constructible, is_pointer, is_reference, is_same, is_scalar, is_signed, remove_const, remove_cv, remove_pointer, remove_reference, true_type, underlying_type
 #include <utility> // declval, forward, make_pair, move, pair, swap
+#include <valarray> // valarray
 #include <vector> // vector
 
 // exclude unsupported compilers
@@ -60,7 +62,7 @@ SOFTWARE.
     #if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
         #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
     #endif
-#elif defined(__GNUC__)
+#elif defined(__GNUC__) && !(defined(__ICC) || defined(__INTEL_COMPILER))
     #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40900
         #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
     #endif
@@ -98,6 +100,23 @@ SOFTWARE.
     #define JSON_CATCH(exception) if(false)
 #endif
 
+// manual branch prediction
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #define JSON_LIKELY(x)      __builtin_expect(!!(x), 1)
+    #define JSON_UNLIKELY(x)    __builtin_expect(!!(x), 0)
+#else
+    #define JSON_LIKELY(x)      x
+    #define JSON_UNLIKELY(x)    x
+#endif
+
+// C++ language standard detection
+#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
+    #define JSON_HAS_CPP_17
+    #define JSON_HAS_CPP_14
+#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
+    #define JSON_HAS_CPP_14
+#endif
+
 /*!
 @brief namespace for Niels Lohmann
 @see https://github.com/nlohmann
@@ -105,6 +124,36 @@ SOFTWARE.
 */
 namespace nlohmann
 {
+template<typename = void, typename = void>
+struct adl_serializer;
+
+// forward declaration of basic_json (required to split the class)
+template<template<typename, typename, typename...> class ObjectType = std::map,
+         template<typename, typename...> class ArrayType = std::vector,
+         class StringType = std::string, class BooleanType = bool,
+         class NumberIntegerType = std::int64_t,
+         class NumberUnsignedType = std::uint64_t,
+         class NumberFloatType = double,
+         template<typename> class AllocatorType = std::allocator,
+         template<typename, typename = void> class JSONSerializer = adl_serializer>
+class basic_json;
+
+// Ugly macros to avoid uglier copy-paste when specializing basic_json. They
+// may be removed in the future once the class is split.
+
+#define NLOHMANN_BASIC_JSON_TPL_DECLARATION                                \
+    template<template<typename, typename, typename...> class ObjectType,   \
+             template<typename, typename...> class ArrayType,              \
+             class StringType, class BooleanType, class NumberIntegerType, \
+             class NumberUnsignedType, class NumberFloatType,              \
+             template<typename> class AllocatorType,                       \
+             template<typename, typename = void> class JSONSerializer>
+
+#define NLOHMANN_BASIC_JSON_TPL                                            \
+    basic_json<ObjectType, ArrayType, StringType, BooleanType,             \
+    NumberIntegerType, NumberUnsignedType, NumberFloatType,                \
+    AllocatorType, JSONSerializer>
+
 
 /*!
 @brief unnamed namespace with internal helper functions
@@ -123,12 +172,28 @@ namespace detail
 /*!
 @brief general exception of the @ref basic_json class
 
-Extension of std::exception objects with a member @a id for exception ids.
+This class is an extension of `std::exception` objects with a member @a id for
+exception ids. It is used as the base class for all exceptions thrown by the
+@ref basic_json class. This class can hence be used as "wildcard" to catch
+exceptions.
 
+Subclasses:
+- @ref parse_error for exceptions indicating a parse error
+- @ref invalid_iterator for exceptions indicating errors with iterators
+- @ref type_error for exceptions indicating executing a member function with
+                  a wrong type
+- @ref out_of_range for exceptions indicating access out of the defined range
+- @ref other_error for exceptions indicating other library errors
+
+@internal
 @note To have nothrow-copy-constructible exceptions, we internally use
-      std::runtime_error which can cope with arbitrary-length error messages.
+      `std::runtime_error` which can cope with arbitrary-length error messages.
       Intermediate strings are built with static functions and then passed to
       the actual constructor.
+@endinternal
+
+@liveexample{The following code shows how arbitrary library exceptions can be
+caught.,exception}
 
 @since version 3.0.0
 */
@@ -136,7 +201,7 @@ class exception : public std::exception
 {
   public:
     /// returns the explanatory string
-    virtual const char* what() const noexcept override
+    const char* what() const noexcept override
     {
         return m.what();
     }
@@ -145,13 +210,11 @@ class exception : public std::exception
     const int id;
 
   protected:
-    exception(int id_, const char* what_arg)
-        : id(id_), m(what_arg)
-    {}
+    exception(int id_, const char* what_arg) : id(id_), m(what_arg) {}
 
-    static std::string name(const std::string& ename, int id)
+    static std::string name(const std::string& ename, int id_)
     {
-        return "[json.exception." + ename + "." + std::to_string(id) + "] ";
+        return "[json.exception." + ename + "." + std::to_string(id_) + "] ";
     }
 
   private:
@@ -162,36 +225,44 @@ class exception : public std::exception
 /*!
 @brief exception indicating a parse error
 
-This excpetion is thrown by the library when a parse error occurs. Parse
-errors can occur during the deserialization of JSON text as well as when
-using JSON Patch.
+This exception is thrown by the library when a parse error occurs. Parse errors
+can occur during the deserialization of JSON text, CBOR, MessagePack, as well
+as when using JSON Patch.
 
 Member @a byte holds the byte index of the last read character in the input
 file.
 
-@note For an input with n bytes, 1 is the index of the first character
-      and n+1 is the index of the terminating null byte or the end of
-      file. This also holds true when reading a byte vector (CBOR or
-      MessagePack).
-
 Exceptions have ids 1xx.
 
-name / id                      | example massage | description
+name / id                      | example message | description
 ------------------------------ | --------------- | -------------------------
 json.exception.parse_error.101 | parse error at 2: unexpected end of input; expected string literal | This error indicates a syntax error while deserializing a JSON text. The error message describes that an unexpected token (character) was encountered, and the member @a byte indicates the error position.
 json.exception.parse_error.102 | parse error at 14: missing or wrong low surrogate | JSON uses the `\uxxxx` format to describe Unicode characters. Code points above above 0xFFFF are split into two `\uxxxx` entries ("surrogate pairs"). This error indicates that the surrogate pair is incomplete or contains an invalid code point.
 json.exception.parse_error.103 | parse error: code points above 0x10FFFF are invalid | Unicode supports code points up to 0x10FFFF. Code points above 0x10FFFF are invalid.
 json.exception.parse_error.104 | parse error: JSON patch must be an array of objects | [RFC 6902](https://tools.ietf.org/html/rfc6902) requires a JSON Patch document to be a JSON document that represents an array of objects.
 json.exception.parse_error.105 | parse error: operation must have string member 'op' | An operation of a JSON Patch document must contain exactly one "op" member, whose value indicates the operation to perform. Its value must be one of "add", "remove", "replace", "move", "copy", or "test"; other values are errors.
-json.exception.parse_error.106 | parse error: array index '01' must not begin with '0' | An array index in a JSON Pointer ([RFC 6901](https://tools.ietf.org/html/rfc6901)) may be `0` or any number wihtout a leading `0`.
+json.exception.parse_error.106 | parse error: array index '01' must not begin with '0' | An array index in a JSON Pointer ([RFC 6901](https://tools.ietf.org/html/rfc6901)) may be `0` or any number without a leading `0`.
 json.exception.parse_error.107 | parse error: JSON pointer must be empty or begin with '/' - was: 'foo' | A JSON Pointer must be a Unicode string containing a sequence of zero or more reference tokens, each prefixed by a `/` character.
 json.exception.parse_error.108 | parse error: escape character '~' must be followed with '0' or '1' | In a JSON Pointer, only `~0` and `~1` are valid escape sequences.
 json.exception.parse_error.109 | parse error: array index 'one' is not a number | A JSON Pointer array index must be a number.
 json.exception.parse_error.110 | parse error at 1: cannot read 2 bytes from vector | When parsing CBOR or MessagePack, the byte vector ends before the complete value has been read.
-json.exception.parse_error.111 | parse error: bad input stream | Parsing CBOR or MessagePack from an input stream where the [`badbit` or `failbit`](http://en.cppreference.com/w/cpp/io/ios_base/iostate) is set.
-json.exception.parse_error.112 | parse error at 1: error reading CBOR; last byte: 0xf8 | Not all types of CBOR or MessagePack are supported. This exception occurs if an unsupported byte was read.
+json.exception.parse_error.112 | parse error at 1: error reading CBOR; last byte: 0xF8 | Not all types of CBOR or MessagePack are supported. This exception occurs if an unsupported byte was read.
 json.exception.parse_error.113 | parse error at 2: expected a CBOR string; last byte: 0x98 | While parsing a map key, a value that is not a string has been read.
 
+@note For an input with n bytes, 1 is the index of the first character and n+1
+      is the index of the terminating null byte or the end of file. This also
+      holds true when reading a byte vector (CBOR or MessagePack).
+
+@liveexample{The following code shows how a `parse_error` exception can be
+caught.,parse_error}
+
+@sa @ref exception for the base class of the library exceptions
+@sa @ref invalid_iterator for exceptions indicating errors with iterators
+@sa @ref type_error for exceptions indicating executing a member function with
+                    a wrong type
+@sa @ref out_of_range for exceptions indicating access out of the defined range
+@sa @ref other_error for exceptions indicating other library errors
+
 @since version 3.0.0
 */
 class parse_error : public exception
@@ -199,18 +270,18 @@ class parse_error : public exception
   public:
     /*!
     @brief create a parse error exception
-    @param[in] id         the id of the exception
-    @param[in] byte_      the byte index where the error occured (or 0 if
-                          the position cannot be determined)
-    @param[in] what_arg   the explanatory string
+    @param[in] id_       the id of the exception
+    @param[in] byte_     the byte index where the error occurred (or 0 if the
+                         position cannot be determined)
+    @param[in] what_arg  the explanatory string
     @return parse_error object
     */
-    static parse_error create(int id, size_t byte_, const std::string& what_arg)
+    static parse_error create(int id_, std::size_t byte_, const std::string& what_arg)
     {
-        std::string w = exception::name("parse_error", id) + "parse error" +
+        std::string w = exception::name("parse_error", id_) + "parse error" +
                         (byte_ != 0 ? (" at " + std::to_string(byte_)) : "") +
                         ": " + what_arg;
-        return parse_error(id, byte_, w.c_str());
+        return parse_error(id_, byte_, w.c_str());
     }
 
     /*!
@@ -218,25 +289,26 @@ class parse_error : public exception
 
     The byte index of the last read character in the input file.
 
-    @note For an input with n bytes, 1 is the index of the first character
-          and n+1 is the index of the terminating null byte or the end of
-          file. This also holds true when reading a byte vector (CBOR or
-          MessagePack).
+    @note For an input with n bytes, 1 is the index of the first character and
+          n+1 is the index of the terminating null byte or the end of file.
+          This also holds true when reading a byte vector (CBOR or MessagePack).
     */
-    const size_t byte;
+    const std::size_t byte;
 
   private:
-    parse_error(int id_, size_t byte_, const char* what_arg)
-        : exception(id_, what_arg), byte(byte_)
-    {}
+    parse_error(int id_, std::size_t byte_, const char* what_arg)
+        : exception(id_, what_arg), byte(byte_) {}
 };
 
 /*!
 @brief exception indicating errors with iterators
 
+This exception is thrown if iterators passed to a library function do not match
+the expected semantics.
+
 Exceptions have ids 2xx.
 
-name / id                           | example massage | description
+name / id                           | example message | description
 ----------------------------------- | --------------- | -------------------------
 json.exception.invalid_iterator.201 | iterators are not compatible | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
 json.exception.invalid_iterator.202 | iterator does not fit current value | In an erase or insert function, the passed iterator @a pos does not belong to the JSON value for which the function was called. It hence does not define a valid position for the deletion/insertion.
@@ -250,32 +322,44 @@ json.exception.invalid_iterator.209 | cannot use offsets with object iterators |
 json.exception.invalid_iterator.210 | iterators do not fit | The iterator range passed to the insert function are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
 json.exception.invalid_iterator.211 | passed iterators may not belong to container | The iterator range passed to the insert function must not be a subrange of the container to insert to.
 json.exception.invalid_iterator.212 | cannot compare iterators of different containers | When two iterators are compared, they must belong to the same container.
-json.exception.invalid_iterator.213 | cannot compare order of object iterators | The order of object iterators cannot be compated, because JSON objects are unordered.
+json.exception.invalid_iterator.213 | cannot compare order of object iterators | The order of object iterators cannot be compared, because JSON objects are unordered.
 json.exception.invalid_iterator.214 | cannot get value | Cannot get value for iterator: Either the iterator belongs to a null value or it is an iterator to a primitive type (number, boolean, or string), but the iterator is different to @ref begin().
 
+@liveexample{The following code shows how an `invalid_iterator` exception can be
+caught.,invalid_iterator}
+
+@sa @ref exception for the base class of the library exceptions
+@sa @ref parse_error for exceptions indicating a parse error
+@sa @ref type_error for exceptions indicating executing a member function with
+                    a wrong type
+@sa @ref out_of_range for exceptions indicating access out of the defined range
+@sa @ref other_error for exceptions indicating other library errors
+
 @since version 3.0.0
 */
 class invalid_iterator : public exception
 {
   public:
-    static invalid_iterator create(int id, const std::string& what_arg)
+    static invalid_iterator create(int id_, const std::string& what_arg)
     {
-        std::string w = exception::name("invalid_iterator", id) + what_arg;
-        return invalid_iterator(id, w.c_str());
+        std::string w = exception::name("invalid_iterator", id_) + what_arg;
+        return invalid_iterator(id_, w.c_str());
     }
 
   private:
     invalid_iterator(int id_, const char* what_arg)
-        : exception(id_, what_arg)
-    {}
+        : exception(id_, what_arg) {}
 };
 
 /*!
 @brief exception indicating executing a member function with a wrong type
 
+This exception is thrown in case of a type error; that is, a library function is
+executed on a JSON value whose type does not match the expected semantics.
+
 Exceptions have ids 3xx.
 
-name / id                     | example massage | description
+name / id                     | example message | description
 ----------------------------- | --------------- | -------------------------
 json.exception.type_error.301 | cannot create object from initializer list | To create an object from an initializer list, the initializer list must consist only of a list of pairs whose first element is a string. When this constraint is violated, an array is created instead.
 json.exception.type_error.302 | type must be object, but is array | During implicit or explicit value conversion, the JSON type must be compatible to the target type. For instance, a JSON string can only be converted into string types, but not into numbers or boolean types.
@@ -288,33 +372,46 @@ json.exception.type_error.308 | cannot use push_back() with string | The @ref pu
 json.exception.type_error.309 | cannot use insert() with | The @ref insert() member functions can only be executed for certain JSON types.
 json.exception.type_error.310 | cannot use swap() with number | The @ref swap() member functions can only be executed for certain JSON types.
 json.exception.type_error.311 | cannot use emplace_back() with string | The @ref emplace_back() member function can only be executed for certain JSON types.
+json.exception.type_error.312 | cannot use update() with string | The @ref update() member functions can only be executed for certain JSON types.
 json.exception.type_error.313 | invalid value to unflatten | The @ref unflatten function converts an object whose keys are JSON Pointers back into an arbitrary nested JSON value. The JSON Pointers must not overlap, because then the resulting value would not be well defined.
 json.exception.type_error.314 | only objects can be unflattened | The @ref unflatten function only works for an object whose keys are JSON Pointers.
 json.exception.type_error.315 | values in object must be primitive | The @ref unflatten function only works for an object whose keys are JSON Pointers and whose values are primitive.
+json.exception.type_error.316 | invalid UTF-8 byte at index 10: 0x7E | The @ref dump function only works with UTF-8 encoded strings; that is, if you assign a `std::string` to a JSON value, make sure it is UTF-8 encoded. |
+
+@liveexample{The following code shows how a `type_error` exception can be
+caught.,type_error}
+
+@sa @ref exception for the base class of the library exceptions
+@sa @ref parse_error for exceptions indicating a parse error
+@sa @ref invalid_iterator for exceptions indicating errors with iterators
+@sa @ref out_of_range for exceptions indicating access out of the defined range
+@sa @ref other_error for exceptions indicating other library errors
 
 @since version 3.0.0
 */
 class type_error : public exception
 {
   public:
-    static type_error create(int id, const std::string& what_arg)
+    static type_error create(int id_, const std::string& what_arg)
     {
-        std::string w = exception::name("type_error", id) + what_arg;
-        return type_error(id, w.c_str());
+        std::string w = exception::name("type_error", id_) + what_arg;
+        return type_error(id_, w.c_str());
     }
 
   private:
-    type_error(int id_, const char* what_arg)
-        : exception(id_, what_arg)
-    {}
+    type_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
 };
 
 /*!
 @brief exception indicating access out of the defined range
 
+This exception is thrown in case a library function is called on an input
+parameter that exceeds the expected range, for instance in case of array
+indices or nonexisting object keys.
+
 Exceptions have ids 4xx.
 
-name / id                       | example massage | description
+name / id                       | example message | description
 ------------------------------- | --------------- | -------------------------
 json.exception.out_of_range.401 | array index 3 is out of range | The provided array index @a i is larger than @a size-1.
 json.exception.out_of_range.402 | array index '-' (3) is out of range | The special array index `-` in a JSON Pointer never describes a valid element of the array, but the index past the end. That is, it can only be used to add elements at this position, but not to read it.
@@ -323,47 +420,66 @@ json.exception.out_of_range.404 | unresolved reference token 'foo' | A reference
 json.exception.out_of_range.405 | JSON pointer has no parent | The JSON Patch operations 'remove' and 'add' can not be applied to the root element of the JSON value.
 json.exception.out_of_range.406 | number overflow parsing '10E1000' | A parsed number could not be stored as without changing it to NaN or INF.
 
+@liveexample{The following code shows how an `out_of_range` exception can be
+caught.,out_of_range}
+
+@sa @ref exception for the base class of the library exceptions
+@sa @ref parse_error for exceptions indicating a parse error
+@sa @ref invalid_iterator for exceptions indicating errors with iterators
+@sa @ref type_error for exceptions indicating executing a member function with
+                    a wrong type
+@sa @ref other_error for exceptions indicating other library errors
+
 @since version 3.0.0
 */
 class out_of_range : public exception
 {
   public:
-    static out_of_range create(int id, const std::string& what_arg)
+    static out_of_range create(int id_, const std::string& what_arg)
     {
-        std::string w = exception::name("out_of_range", id) + what_arg;
-        return out_of_range(id, w.c_str());
+        std::string w = exception::name("out_of_range", id_) + what_arg;
+        return out_of_range(id_, w.c_str());
     }
 
   private:
-    out_of_range(int id_, const char* what_arg)
-        : exception(id_, what_arg)
-    {}
+    out_of_range(int id_, const char* what_arg) : exception(id_, what_arg) {}
 };
 
 /*!
-@brief exception indicating other errors
+@brief exception indicating other library errors
+
+This exception is thrown in case of errors that cannot be classified with the
+other exception types.
 
 Exceptions have ids 5xx.
 
-name / id                      | example massage | description
+name / id                      | example message | description
 ------------------------------ | --------------- | -------------------------
 json.exception.other_error.501 | unsuccessful: {"op":"test","path":"/baz", "value":"bar"} | A JSON Patch operation 'test' failed. The unsuccessful operation is also printed.
 
+@sa @ref exception for the base class of the library exceptions
+@sa @ref parse_error for exceptions indicating a parse error
+@sa @ref invalid_iterator for exceptions indicating errors with iterators
+@sa @ref type_error for exceptions indicating executing a member function with
+                    a wrong type
+@sa @ref out_of_range for exceptions indicating access out of the defined range
+
+@liveexample{The following code shows how an `other_error` exception can be
+caught.,other_error}
+
 @since version 3.0.0
 */
 class other_error : public exception
 {
   public:
-    static other_error create(int id, const std::string& what_arg)
+    static other_error create(int id_, const std::string& what_arg)
     {
-        std::string w = exception::name("other_error", id) + what_arg;
-        return other_error(id, w.c_str());
+        std::string w = exception::name("other_error", id_) + what_arg;
+        return other_error(id_, w.c_str());
     }
 
   private:
-    other_error(int id_, const char* what_arg)
-        : exception(id_, what_arg)
-    {}
+    other_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
 };
 
 
@@ -398,15 +514,15 @@ value with the default value for a given type
 */
 enum class value_t : uint8_t
 {
-    null,            ///< null value
-    object,          ///< object (unordered set of name/value pairs)
-    array,           ///< array (ordered collection of values)
-    string,          ///< string value
-    boolean,         ///< boolean value
-    number_integer,  ///< number value (signed integer)
-    number_unsigned, ///< number value (unsigned integer)
-    number_float,    ///< number value (floating-point)
-    discarded        ///< discarded by the the parser callback function
+    null,             ///< null value
+    object,           ///< object (unordered set of name/value pairs)
+    array,            ///< array (ordered collection of values)
+    string,           ///< string value
+    boolean,          ///< boolean value
+    number_integer,   ///< number value (signed integer)
+    number_unsigned,  ///< number value (unsigned integer)
+    number_float,     ///< number value (floating-point)
+    discarded         ///< discarded by the the parser callback function
 };
 
 /*!
@@ -415,31 +531,21 @@ enum class value_t : uint8_t
 Returns an ordering that is similar to Python:
 - order: null < boolean < number < object < array < string
 - furthermore, each type is not smaller than itself
+- discarded values are not comparable
 
 @since version 1.0.0
 */
 inline bool operator<(const value_t lhs, const value_t rhs) noexcept
 {
     static constexpr std::array<uint8_t, 8> order = {{
-            0, // null
-            3, // object
-            4, // array
-            5, // string
-            1, // boolean
-            2, // integer
-            2, // unsigned
-            2, // float
+            0 /* null */, 3 /* object */, 4 /* array */, 5 /* string */,
+            1 /* boolean */, 2 /* integer */, 2 /* unsigned */, 2 /* float */
         }
     };
 
-    // discarded values are not comparable
-    if (lhs == value_t::discarded or rhs == value_t::discarded)
-    {
-        return false;
-    }
-
-    return order[static_cast<std::size_t>(lhs)] <
-           order[static_cast<std::size_t>(rhs)];
+    const auto l_index = static_cast<std::size_t>(lhs);
+    const auto r_index = static_cast<std::size_t>(rhs);
+    return l_index < order.size() and r_index < order.size() and order[l_index] < order[r_index];
 }
 
 
@@ -447,6 +553,11 @@ inline bool operator<(const value_t lhs, const value_t rhs) noexcept
 // helpers //
 /////////////
 
+template<typename> struct is_basic_json : std::false_type {};
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+struct is_basic_json<NLOHMANN_BASIC_JSON_TPL> : std::true_type {};
+
 // alias templates to reduce boilerplate
 template<bool B, typename T = void>
 using enable_if_t = typename std::enable_if<B, T>::type;
@@ -454,6 +565,37 @@ using enable_if_t = typename std::enable_if<B, T>::type;
 template<typename T>
 using uncvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type;
 
+// implementation of C++14 index_sequence and affiliates
+// source: https://stackoverflow.com/a/32223343
+template<std::size_t... Ints>
+struct index_sequence
+{
+    using type = index_sequence;
+    using value_type = std::size_t;
+    static constexpr std::size_t size() noexcept
+    {
+        return sizeof...(Ints);
+    }
+};
+
+template<class Sequence1, class Sequence2>
+struct merge_and_renumber;
+
+template<std::size_t... I1, std::size_t... I2>
+struct merge_and_renumber<index_sequence<I1...>, index_sequence<I2...>>
+        : index_sequence < I1..., (sizeof...(I1) + I2)... > {};
+
+template<std::size_t N>
+struct make_index_sequence
+    : merge_and_renumber < typename make_index_sequence < N / 2 >::type,
+      typename make_index_sequence < N - N / 2 >::type > {};
+
+template<> struct make_index_sequence<0> : index_sequence<> {};
+template<> struct make_index_sequence<1> : index_sequence<0> {};
+
+template<typename... Ts>
+using index_sequence_for = make_index_sequence<sizeof...(Ts)>;
+
 /*
 Implementation of two C++17 constructs: conjunction, negation. This is needed
 to avoid evaluating all the traits in a condition
@@ -472,7 +614,7 @@ template<class B1> struct conjunction<B1> : B1 {};
 template<class B1, class... Bn>
 struct conjunction<B1, Bn...> : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
 
-template<class B> struct negation : std::integral_constant < bool, !B::value > {};
+template<class B> struct negation : std::integral_constant<bool, not B::value> {};
 
 // dispatch utility (taken from ranges-v3)
 template<unsigned N> struct priority_tag : priority_tag < N - 1 > {};
@@ -507,6 +649,14 @@ struct external_constructor<value_t::string>
         j.m_value = s;
         j.assert_invariant();
     }
+
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::string_t&& s)
+    {
+        j.m_type = value_t::string;
+        j.m_value = std::move(s);
+        j.assert_invariant();
+    }
 };
 
 template<>
@@ -556,9 +706,16 @@ struct external_constructor<value_t::array>
         j.assert_invariant();
     }
 
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
+    {
+        j.m_type = value_t::array;
+        j.m_value = std::move(arr);
+        j.assert_invariant();
+    }
+
     template<typename BasicJsonType, typename CompatibleArrayType,
-             enable_if_t<not std::is_same<CompatibleArrayType,
-                                          typename BasicJsonType::array_t>::value,
+             enable_if_t<not std::is_same<CompatibleArrayType, typename BasicJsonType::array_t>::value,
                          int> = 0>
     static void construct(BasicJsonType& j, const CompatibleArrayType& arr)
     {
@@ -575,12 +732,23 @@ struct external_constructor<value_t::array>
         j.m_type = value_t::array;
         j.m_value = value_t::array;
         j.m_value.array->reserve(arr.size());
-        for (bool x : arr)
+        for (const bool x : arr)
         {
             j.m_value.array->push_back(x);
         }
         j.assert_invariant();
     }
+
+    template<typename BasicJsonType, typename T,
+             enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
+    static void construct(BasicJsonType& j, const std::valarray<T>& arr)
+    {
+        j.m_type = value_t::array;
+        j.m_value = value_t::array;
+        j.m_value.array->resize(arr.size());
+        std::copy(std::begin(arr), std::end(arr), j.m_value.array->begin());
+        j.assert_invariant();
+    }
 };
 
 template<>
@@ -594,10 +762,16 @@ struct external_constructor<value_t::object>
         j.assert_invariant();
     }
 
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
+    {
+        j.m_type = value_t::object;
+        j.m_value = std::move(obj);
+        j.assert_invariant();
+    }
+
     template<typename BasicJsonType, typename CompatibleObjectType,
-             enable_if_t<not std::is_same<CompatibleObjectType,
-                                          typename BasicJsonType::object_t>::value,
-                         int> = 0>
+             enable_if_t<not std::is_same<CompatibleObjectType, typename BasicJsonType::object_t>::value, int> = 0>
     static void construct(BasicJsonType& j, const CompatibleObjectType& obj)
     {
         using std::begin;
@@ -650,10 +824,8 @@ template<class RealType, class CompatibleObjectType>
 struct is_compatible_object_type_impl<true, RealType, CompatibleObjectType>
 {
     static constexpr auto value =
-        std::is_constructible<typename RealType::key_type,
-        typename CompatibleObjectType::key_type>::value and
-        std::is_constructible<typename RealType::mapped_type,
-        typename CompatibleObjectType::mapped_type>::value;
+        std::is_constructible<typename RealType::key_type, typename CompatibleObjectType::key_type>::value and
+        std::is_constructible<typename RealType::mapped_type, typename CompatibleObjectType::mapped_type>::value;
 };
 
 template<class BasicJsonType, class CompatibleObjectType>
@@ -672,8 +844,7 @@ struct is_basic_json_nested_type
     static auto constexpr value = std::is_same<T, typename BasicJsonType::iterator>::value or
                                   std::is_same<T, typename BasicJsonType::const_iterator>::value or
                                   std::is_same<T, typename BasicJsonType::reverse_iterator>::value or
-                                  std::is_same<T, typename BasicJsonType::const_reverse_iterator>::value or
-                                  std::is_same<T, typename BasicJsonType::json_pointer>::value;
+                                  std::is_same<T, typename BasicJsonType::const_reverse_iterator>::value;
 };
 
 template<class BasicJsonType, class CompatibleArrayType>
@@ -701,8 +872,7 @@ struct is_compatible_integer_type_impl<true, RealIntegerType, CompatibleNumberIn
     using CompatibleLimits = std::numeric_limits<CompatibleNumberIntegerType>;
 
     static constexpr auto value =
-        std::is_constructible<RealIntegerType,
-        CompatibleNumberIntegerType>::value and
+        std::is_constructible<RealIntegerType, CompatibleNumberIntegerType>::value and
         CompatibleLimits::is_integer and
         RealLimits::is_signed == CompatibleLimits::is_signed;
 };
@@ -714,7 +884,7 @@ struct is_compatible_integer_type
         is_compatible_integer_type_impl <
         std::is_integral<CompatibleNumberIntegerType>::value and
         not std::is_same<bool, CompatibleNumberIntegerType>::value,
-        RealIntegerType, CompatibleNumberIntegerType > ::value;
+        RealIntegerType, CompatibleNumberIntegerType >::value;
 };
 
 
@@ -740,10 +910,8 @@ template<typename BasicJsonType, typename T>
 struct has_non_default_from_json
 {
   private:
-    template <
-        typename U,
-        typename = enable_if_t<std::is_same<
-                                   T, decltype(uncvref_t<U>::from_json(std::declval<BasicJsonType>()))>::value >>
+    template<typename U, typename =
+             enable_if_t<std::is_same<T, decltype(uncvref_t<U>::from_json(std::declval<BasicJsonType>()))>::value>>
     static int detect(U&&);
     static void detect(...);
 
@@ -772,21 +940,26 @@ struct has_to_json
 // to_json //
 /////////////
 
-template<typename BasicJsonType, typename T, enable_if_t<
-             std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
+template<typename BasicJsonType, typename T,
+         enable_if_t<std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
 void to_json(BasicJsonType& j, T b) noexcept
 {
     external_constructor<value_t::boolean>::construct(j, b);
 }
 
 template<typename BasicJsonType, typename CompatibleString,
-         enable_if_t<std::is_constructible<typename BasicJsonType::string_t,
-                     CompatibleString>::value, int> = 0>
+         enable_if_t<std::is_constructible<typename BasicJsonType::string_t, CompatibleString>::value, int> = 0>
 void to_json(BasicJsonType& j, const CompatibleString& s)
 {
     external_constructor<value_t::string>::construct(j, s);
 }
 
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, typename BasicJsonType::string_t&& s)
+{
+    external_constructor<value_t::string>::construct(j, std::move(s));
+}
+
 template<typename BasicJsonType, typename FloatType,
          enable_if_t<std::is_floating_point<FloatType>::value, int> = 0>
 void to_json(BasicJsonType& j, FloatType val) noexcept
@@ -794,19 +967,15 @@ void to_json(BasicJsonType& j, FloatType val) noexcept
     external_constructor<value_t::number_float>::construct(j, static_cast<typename BasicJsonType::number_float_t>(val));
 }
 
-template <
-    typename BasicJsonType, typename CompatibleNumberUnsignedType,
-    enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t,
-                CompatibleNumberUnsignedType>::value, int> = 0 >
+template<typename BasicJsonType, typename CompatibleNumberUnsignedType,
+         enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t, CompatibleNumberUnsignedType>::value, int> = 0>
 void to_json(BasicJsonType& j, CompatibleNumberUnsignedType val) noexcept
 {
     external_constructor<value_t::number_unsigned>::construct(j, static_cast<typename BasicJsonType::number_unsigned_t>(val));
 }
 
-template <
-    typename BasicJsonType, typename CompatibleNumberIntegerType,
-    enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t,
-                CompatibleNumberIntegerType>::value, int> = 0 >
+template<typename BasicJsonType, typename CompatibleNumberIntegerType,
+         enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t, CompatibleNumberIntegerType>::value, int> = 0>
 void to_json(BasicJsonType& j, CompatibleNumberIntegerType val) noexcept
 {
     external_constructor<value_t::number_integer>::construct(j, static_cast<typename BasicJsonType::number_integer_t>(val));
@@ -826,35 +995,66 @@ void to_json(BasicJsonType& j, const std::vector<bool>& e)
     external_constructor<value_t::array>::construct(j, e);
 }
 
-template <
-    typename BasicJsonType, typename CompatibleArrayType,
-    enable_if_t <
-        is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value or
-        std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value,
-        int > = 0 >
-void to_json(BasicJsonType& j, const  CompatibleArrayType& arr)
+template<typename BasicJsonType, typename CompatibleArrayType,
+         enable_if_t<is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value or
+                     std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value,
+                     int> = 0>
+void to_json(BasicJsonType& j, const CompatibleArrayType& arr)
 {
     external_constructor<value_t::array>::construct(j, arr);
 }
 
-template <
-    typename BasicJsonType, typename CompatibleObjectType,
-    enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value,
-                int> = 0 >
-void to_json(BasicJsonType& j, const  CompatibleObjectType& arr)
+template<typename BasicJsonType, typename T,
+         enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
+void to_json(BasicJsonType& j, std::valarray<T> arr)
+{
+    external_constructor<value_t::array>::construct(j, std::move(arr));
+}
+
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
+{
+    external_constructor<value_t::array>::construct(j, std::move(arr));
+}
+
+template<typename BasicJsonType, typename CompatibleObjectType,
+         enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value, int> = 0>
+void to_json(BasicJsonType& j, const CompatibleObjectType& obj)
+{
+    external_constructor<value_t::object>::construct(j, obj);
+}
+
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
 {
-    external_constructor<value_t::object>::construct(j, arr);
+    external_constructor<value_t::object>::construct(j, std::move(obj));
 }
 
-template <typename BasicJsonType, typename T, std::size_t N,
-          enable_if_t<not std::is_constructible<
-                          typename BasicJsonType::string_t, T (&)[N]>::value,
-                      int> = 0>
+template<typename BasicJsonType, typename T, std::size_t N,
+         enable_if_t<not std::is_constructible<typename BasicJsonType::string_t, T (&)[N]>::value, int> = 0>
 void to_json(BasicJsonType& j, T (&arr)[N])
 {
     external_constructor<value_t::array>::construct(j, arr);
 }
 
+template<typename BasicJsonType, typename... Args>
+void to_json(BasicJsonType& j, const std::pair<Args...>& p)
+{
+    j = {p.first, p.second};
+}
+
+template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
+void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<Idx...>)
+{
+    j = {std::get<Idx>(t)...};
+}
+
+template<typename BasicJsonType, typename... Args>
+void to_json(BasicJsonType& j, const std::tuple<Args...>& t)
+{
+    to_json_tuple_impl(j, t, index_sequence_for<Args...> {});
+}
+
 ///////////////
 // from_json //
 ///////////////
@@ -862,8 +1062,7 @@ void to_json(BasicJsonType& j, T (&arr)[N])
 // overloads for basic_json template parameters
 template<typename BasicJsonType, typename ArithmeticType,
          enable_if_t<std::is_arithmetic<ArithmeticType>::value and
-                     not std::is_same<ArithmeticType,
-                                      typename BasicJsonType::boolean_t>::value,
+                     not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
                      int> = 0>
 void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
 {
@@ -871,35 +1070,31 @@ void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
     {
         case value_t::number_unsigned:
         {
-            val = static_cast<ArithmeticType>(
-                      *j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
             break;
         }
         case value_t::number_integer:
         {
-            val = static_cast<ArithmeticType>(
-                      *j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
             break;
         }
         case value_t::number_float:
         {
-            val = static_cast<ArithmeticType>(
-                      *j.template get_ptr<const typename BasicJsonType::number_float_t*>());
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
             break;
         }
+
         default:
-        {
-            JSON_THROW(type_error::create(302, "type must be number, but is " + j.type_name()));
-        }
+            JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
     }
 }
 
 template<typename BasicJsonType>
 void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
 {
-    if (not j.is_boolean())
+    if (JSON_UNLIKELY(not j.is_boolean()))
     {
-        JSON_THROW(type_error::create(302, "type must be boolean, but is " + j.type_name()));
+        JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(j.type_name())));
     }
     b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
 }
@@ -907,9 +1102,9 @@ void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
 template<typename BasicJsonType>
 void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s)
 {
-    if (not j.is_string())
+    if (JSON_UNLIKELY(not j.is_string()))
     {
-        JSON_THROW(type_error::create(302, "type must be string, but is " + j.type_name()));
+        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
     }
     s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
 }
@@ -944,9 +1139,9 @@ void from_json(const BasicJsonType& j, EnumType& e)
 template<typename BasicJsonType>
 void from_json(const BasicJsonType& j, typename BasicJsonType::array_t& arr)
 {
-    if (not j.is_array())
+    if (JSON_UNLIKELY(not j.is_array()))
     {
-        JSON_THROW(type_error::create(302, "type must be array, but is " + j.type_name()));
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
     }
     arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
 }
@@ -956,21 +1151,33 @@ template<typename BasicJsonType, typename T, typename Allocator,
          enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
 void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
 {
-    if (not j.is_array())
+    if (JSON_UNLIKELY(not j.is_array()))
     {
-        JSON_THROW(type_error::create(302, "type must be array, but is " + j.type_name()));
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
     }
+    std::transform(j.rbegin(), j.rend(),
+                   std::front_inserter(l), [](const BasicJsonType & i)
+    {
+        return i.template get<T>();
+    });
+}
 
-    for (auto it = j.rbegin(), end = j.rend(); it != end; ++it)
+// valarray doesn't have an insert method
+template<typename BasicJsonType, typename T,
+         enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
+void from_json(const BasicJsonType& j, std::valarray<T>& l)
+{
+    if (JSON_UNLIKELY(not j.is_array()))
     {
-        l.push_front(it->template get<T>());
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
     }
+    l.resize(j.size());
+    std::copy(j.m_value.array->begin(), j.m_value.array->end(), std::begin(l));
 }
 
 template<typename BasicJsonType, typename CompatibleArrayType>
-void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<0>)
+void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<0> /*unused*/)
 {
-    using std::begin;
     using std::end;
 
     std::transform(j.begin(), j.end(),
@@ -983,12 +1190,11 @@ void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, prio
 }
 
 template<typename BasicJsonType, typename CompatibleArrayType>
-auto from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<1>)
+auto from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<1> /*unused*/)
 -> decltype(
     arr.reserve(std::declval<typename CompatibleArrayType::size_type>()),
     void())
 {
-    using std::begin;
     using std::end;
 
     arr.reserve(j.size());
@@ -1001,36 +1207,47 @@ auto from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, prio
     });
 }
 
+template<typename BasicJsonType, typename T, std::size_t N>
+void from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr, priority_tag<2> /*unused*/)
+{
+    for (std::size_t i = 0; i < N; ++i)
+    {
+        arr[i] = j.at(i).template get<T>();
+    }
+}
+
 template<typename BasicJsonType, typename CompatibleArrayType,
          enable_if_t<is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value and
                      std::is_convertible<BasicJsonType, typename CompatibleArrayType::value_type>::value and
                      not std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value, int> = 0>
 void from_json(const BasicJsonType& j, CompatibleArrayType& arr)
 {
-    if (not j.is_array())
+    if (JSON_UNLIKELY(not j.is_array()))
     {
-        JSON_THROW(type_error::create(302, "type must be array, but is " + j.type_name()));
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
     }
 
-    from_json_array_impl(j, arr, priority_tag<1> {});
+    from_json_array_impl(j, arr, priority_tag<2> {});
 }
 
 template<typename BasicJsonType, typename CompatibleObjectType,
          enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value, int> = 0>
 void from_json(const BasicJsonType& j, CompatibleObjectType& obj)
 {
-    if (not j.is_object())
+    if (JSON_UNLIKELY(not j.is_object()))
     {
-        JSON_THROW(type_error::create(302, "type must be object, but is " + j.type_name()));
+        JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name())));
     }
 
     auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
-    using std::begin;
-    using std::end;
-    // we could avoid the assignment, but this might require a for loop, which
-    // might be less efficient than the container constructor for some
-    // containers (would it?)
-    obj = CompatibleObjectType(begin(*inner_object), end(*inner_object));
+    using value_type = typename CompatibleObjectType::value_type;
+    std::transform(
+        inner_object->begin(), inner_object->end(),
+        std::inserter(obj, obj.begin()),
+        [](typename BasicJsonType::object_t::value_type const & p)
+    {
+        return value_type(p.first, p.second.template get<typename CompatibleObjectType::mapped_type>());
+    });
 }
 
 // overload for arithmetic types, not chosen for basic_json template arguments
@@ -1069,28 +1286,52 @@ void from_json(const BasicJsonType& j, ArithmeticType& val)
             val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>());
             break;
         }
+
         default:
-        {
-            JSON_THROW(type_error::create(302, "type must be number, but is " + j.type_name()));
-        }
+            JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
     }
 }
 
+template<typename BasicJsonType, typename A1, typename A2>
+void from_json(const BasicJsonType& j, std::pair<A1, A2>& p)
+{
+    p = {j.at(0).template get<A1>(), j.at(1).template get<A2>()};
+}
+
+template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
+void from_json_tuple_impl(const BasicJsonType& j, Tuple& t, index_sequence<Idx...>)
+{
+    t = std::make_tuple(j.at(Idx).template get<typename std::tuple_element<Idx, Tuple>::type>()...);
+}
+
+template<typename BasicJsonType, typename... Args>
+void from_json(const BasicJsonType& j, std::tuple<Args...>& t)
+{
+    from_json_tuple_impl(j, t, index_sequence_for<Args...> {});
+}
+
 struct to_json_fn
 {
   private:
     template<typename BasicJsonType, typename T>
-    auto call(BasicJsonType& j, T&& val, priority_tag<1>) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
+    auto call(BasicJsonType& j, T&& val, priority_tag<1> /*unused*/) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
     -> decltype(to_json(j, std::forward<T>(val)), void())
     {
         return to_json(j, std::forward<T>(val));
     }
 
     template<typename BasicJsonType, typename T>
-    void call(BasicJsonType&, T&&, priority_tag<0>) const noexcept
+    void call(BasicJsonType& /*unused*/, T&& /*unused*/, priority_tag<0> /*unused*/) const noexcept
     {
         static_assert(sizeof(BasicJsonType) == 0,
                       "could not find to_json() method in T's namespace");
+
+#ifdef _MSC_VER
+        // MSVC does not show a stacktrace for the above assert
+        using decayed = uncvref_t<T>;
+        static_assert(sizeof(typename decayed::force_msvc_stacktrace) == 0,
+                      "forcing MSVC stacktrace to show which T we're talking about.");
+#endif
     }
 
   public:
@@ -1106,7 +1347,7 @@ struct from_json_fn
 {
   private:
     template<typename BasicJsonType, typename T>
-    auto call(const BasicJsonType& j, T& val, priority_tag<1>) const
+    auto call(const BasicJsonType& j, T& val, priority_tag<1> /*unused*/) const
     noexcept(noexcept(from_json(j, val)))
     -> decltype(from_json(j, val), void())
     {
@@ -1114,10 +1355,16 @@ struct from_json_fn
     }
 
     template<typename BasicJsonType, typename T>
-    void call(const BasicJsonType&, T&, priority_tag<0>) const noexcept
+    void call(const BasicJsonType& /*unused*/, T& /*unused*/, priority_tag<0> /*unused*/) const noexcept
     {
         static_assert(sizeof(BasicJsonType) == 0,
                       "could not find from_json() method in T's namespace");
+#ifdef _MSC_VER
+        // MSVC does not show a stacktrace for the above assert
+        using decayed = uncvref_t<T>;
+        static_assert(sizeof(typename decayed::force_msvc_stacktrace) == 0,
+                      "forcing MSVC stacktrace to show which T we're talking about.");
+#endif
     }
 
   public:
@@ -1138,12073 +1385,12265 @@ struct static_const
 
 template<typename T>
 constexpr T static_const<T>::value;
-} // namespace detail
 
+////////////////////
+// input adapters //
+////////////////////
 
-/// namespace to hold default `to_json` / `from_json` functions
-namespace
+/*!
+@brief abstract input adapter interface
+
+Produces a stream of std::char_traits<char>::int_type characters from a
+std::istream, a buffer, or some other input type.  Accepts the return of exactly
+one non-EOF character for future input.  The int_type characters returned
+consist of all valid char values as positive values (typically unsigned char),
+plus an EOF value outside that range, specified by the value of the function
+std::char_traits<char>::eof().  This value is typically -1, but could be any
+arbitrary value which is not a valid char value.
+*/
+struct input_adapter_protocol
 {
-constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value;
-constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
-}
+    /// get a character [0,255] or std::char_traits<char>::eof().
+    virtual std::char_traits<char>::int_type get_character() = 0;
+    /// restore the last non-eof() character to input
+    virtual void unget_character() = 0;
+    virtual ~input_adapter_protocol() = default;
+};
 
+/// a type to simplify interfaces
+using input_adapter_t = std::shared_ptr<input_adapter_protocol>;
 
 /*!
-@brief default JSONSerializer template argument
-
-This serializer ignores the template arguments and uses ADL
-([argument-dependent lookup](http://en.cppreference.com/w/cpp/language/adl))
-for serialization.
+Input adapter for a (caching) istream. Ignores a UFT Byte Order Mark at
+beginning of input. Does not support changing the underlying std::streambuf
+in mid-input. Maintains underlying std::istream and std::streambuf to support
+subsequent use of standard std::istream operations to process any input
+characters following those used in parsing the JSON input.  Clears the
+std::istream flags; any input errors (e.g., EOF) will be detected by the first
+subsequent call for input from the std::istream.
 */
-template<typename = void, typename = void>
-struct adl_serializer
+class input_stream_adapter : public input_adapter_protocol
 {
-    /*!
-    @brief convert a JSON value to any value type
+  public:
+    ~input_stream_adapter() override
+    {
+        // clear stream flags; we use underlying streambuf I/O, do not
+        // maintain ifstream flags
+        is.clear();
+    }
 
-    This function is usually called by the `get()` function of the
-    @ref basic_json class (either explicit or via conversion operators).
+    explicit input_stream_adapter(std::istream& i)
+        : is(i), sb(*i.rdbuf())
+    {
+        // skip byte order mark
+        std::char_traits<char>::int_type c;
+        if ((c = get_character()) == 0xEF)
+        {
+            if ((c = get_character()) == 0xBB)
+            {
+                if ((c = get_character()) == 0xBF)
+                {
+                    return; // Ignore BOM
+                }
+                else if (c != std::char_traits<char>::eof())
+                {
+                    is.unget();
+                }
+                is.putback('\xBB');
+            }
+            else if (c != std::char_traits<char>::eof())
+            {
+                is.unget();
+            }
+            is.putback('\xEF');
+        }
+        else if (c != std::char_traits<char>::eof())
+        {
+            is.unget(); // no byte order mark; process as usual
+        }
+    }
 
-    @param[in] j         JSON value to read from
-    @param[in,out] val  value to write to
-    */
-    template<typename BasicJsonType, typename ValueType>
-    static void from_json(BasicJsonType&& j, ValueType& val) noexcept(
-        noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), val)))
+    // delete because of pointer members
+    input_stream_adapter(const input_stream_adapter&) = delete;
+    input_stream_adapter& operator=(input_stream_adapter&) = delete;
+
+    // std::istream/std::streambuf use std::char_traits<char>::to_int_type, to
+    // ensure that std::char_traits<char>::eof() and the character 0xFF do not
+    // end up as the same value, eg. 0xFFFFFFFF.
+    std::char_traits<char>::int_type get_character() override
     {
-        ::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
+        return sb.sbumpc();
     }
 
-    /*!
-    @brief convert any value type to a JSON value
+    void unget_character() override
+    {
+        sb.sungetc();  // is.unget() avoided for performance
+    }
 
-    This function is usually called by the constructors of the @ref basic_json
-    class.
+  private:
+    /// the associated input stream
+    std::istream& is;
+    std::streambuf& sb;
+};
 
-    @param[in,out] j  JSON value to write to
-    @param[in] val     value to read from
-    */
-    template<typename BasicJsonType, typename ValueType>
-    static void to_json(BasicJsonType& j, ValueType&& val) noexcept(
-        noexcept(::nlohmann::to_json(j, std::forward<ValueType>(val))))
+/// input adapter for buffer input
+class input_buffer_adapter : public input_adapter_protocol
+{
+  public:
+    input_buffer_adapter(const char* b, const std::size_t l)
+        : cursor(b), limit(b + l), start(b)
     {
-        ::nlohmann::to_json(j, std::forward<ValueType>(val));
+        // skip byte order mark
+        if (l >= 3 and b[0] == '\xEF' and b[1] == '\xBB' and b[2] == '\xBF')
+        {
+            cursor += 3;
+        }
+    }
+
+    // delete because of pointer members
+    input_buffer_adapter(const input_buffer_adapter&) = delete;
+    input_buffer_adapter& operator=(input_buffer_adapter&) = delete;
+
+    std::char_traits<char>::int_type get_character() noexcept override
+    {
+        if (JSON_LIKELY(cursor < limit))
+        {
+            return std::char_traits<char>::to_int_type(*(cursor++));
+        }
+
+        return std::char_traits<char>::eof();
     }
+
+    void unget_character() noexcept override
+    {
+        if (JSON_LIKELY(cursor > start))
+        {
+            --cursor;
+        }
+    }
+
+  private:
+    /// pointer to the current character
+    const char* cursor;
+    /// pointer past the last character
+    const char* limit;
+    /// pointer to the first character
+    const char* start;
 };
 
+class input_adapter
+{
+  public:
+    // native support
 
-/*!
-@brief a class to store JSON values
+    /// input adapter for input stream
+    input_adapter(std::istream& i)
+        : ia(std::make_shared<input_stream_adapter>(i)) {}
 
-@tparam ObjectType type for JSON objects (`std::map` by default; will be used
-in @ref object_t)
-@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
-in @ref array_t)
-@tparam StringType type for JSON strings and object keys (`std::string` by
-default; will be used in @ref string_t)
-@tparam BooleanType type for JSON booleans (`bool` by default; will be used
-in @ref boolean_t)
-@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
-default; will be used in @ref number_integer_t)
-@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
-`uint64_t` by default; will be used in @ref number_unsigned_t)
-@tparam NumberFloatType type for JSON floating-point numbers (`double` by
-default; will be used in @ref number_float_t)
-@tparam AllocatorType type of the allocator to use (`std::allocator` by
-default)
-@tparam JSONSerializer the serializer to resolve internal calls to `to_json()`
-and `from_json()` (@ref adl_serializer by default)
+    /// input adapter for input stream
+    input_adapter(std::istream&& i)
+        : ia(std::make_shared<input_stream_adapter>(i)) {}
 
-@requirement The class satisfies the following concept requirements:
-- Basic
- - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
-   JSON values can be default constructed. The result will be a JSON null
-   value.
- - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
-   A JSON value can be constructed from an rvalue argument.
- - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
-   A JSON value can be copy-constructed from an lvalue expression.
- - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
-   A JSON value van be assigned from an rvalue argument.
- - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
-   A JSON value can be copy-assigned from an lvalue expression.
- - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
-   JSON values can be destructed.
-- Layout
- - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
-   JSON values have
-   [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
-   All non-static data members are private and standard layout types, the
-   class has no virtual functions or (virtual) base classes.
-- Library-wide
- - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
-   JSON values can be compared with `==`, see @ref
-   operator==(const_reference,const_reference).
- - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
-   JSON values can be compared with `<`, see @ref
-   operator<(const_reference,const_reference).
- - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
-   Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
-   other compatible types, using unqualified function call @ref swap().
- - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
-   JSON values can be compared against `std::nullptr_t` objects which are used
-   to model the `null` value.
-- Container
- - [Container](http://en.cppreference.com/w/cpp/concept/Container):
-   JSON values can be used like STL containers and provide iterator access.
- - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
-   JSON values can be used like STL containers and provide reverse iterator
-   access.
+    /// input adapter for buffer
+    template<typename CharT,
+             typename std::enable_if<
+                 std::is_pointer<CharT>::value and
+                 std::is_integral<typename std::remove_pointer<CharT>::type>::value and
+                 sizeof(typename std::remove_pointer<CharT>::type) == 1,
+                 int>::type = 0>
+    input_adapter(CharT b, std::size_t l)
+        : ia(std::make_shared<input_buffer_adapter>(reinterpret_cast<const char*>(b), l)) {}
 
-@invariant The member variables @a m_value and @a m_type have the following
-relationship:
-- If `m_type == value_t::object`, then `m_value.object != nullptr`.
-- If `m_type == value_t::array`, then `m_value.array != nullptr`.
-- If `m_type == value_t::string`, then `m_value.string != nullptr`.
-The invariants are checked by member function assert_invariant().
+    // derived support
 
-@internal
-@note ObjectType trick from http://stackoverflow.com/a/9860911
-@endinternal
+    /// input adapter for string literal
+    template<typename CharT,
+             typename std::enable_if<
+                 std::is_pointer<CharT>::value and
+                 std::is_integral<typename std::remove_pointer<CharT>::type>::value and
+                 sizeof(typename std::remove_pointer<CharT>::type) == 1,
+                 int>::type = 0>
+    input_adapter(CharT b)
+        : input_adapter(reinterpret_cast<const char*>(b),
+                        std::strlen(reinterpret_cast<const char*>(b))) {}
+
+    /// input adapter for iterator range with contiguous storage
+    template<class IteratorType,
+             typename std::enable_if<
+                 std::is_same<typename std::iterator_traits<IteratorType>::iterator_category, std::random_access_iterator_tag>::value,
+                 int>::type = 0>
+    input_adapter(IteratorType first, IteratorType last)
+    {
+        // assertion to check that the iterator range is indeed contiguous,
+        // see http://stackoverflow.com/a/35008842/266378 for more discussion
+        assert(std::accumulate(
+                   first, last, std::pair<bool, int>(true, 0),
+                   [&first](std::pair<bool, int> res, decltype(*first) val)
+        {
+            res.first &= (val == *(std::next(std::addressof(*first), res.second++)));
+            return res;
+        }).first);
 
-@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
-Format](http://rfc7159.net/rfc7159)
+        // assertion to check that each element is 1 byte long
+        static_assert(
+            sizeof(typename std::iterator_traits<IteratorType>::value_type) == 1,
+            "each element in the iterator range must have the size of 1 byte");
 
-@since version 1.0.0
+        const auto len = static_cast<size_t>(std::distance(first, last));
+        if (JSON_LIKELY(len > 0))
+        {
+            // there is at least one element: use the address of first
+            ia = std::make_shared<input_buffer_adapter>(reinterpret_cast<const char*>(&(*first)), len);
+        }
+        else
+        {
+            // the address of first cannot be used: use nullptr
+            ia = std::make_shared<input_buffer_adapter>(nullptr, len);
+        }
+    }
 
-@nosubgrouping
-*/
-template <
-    template<typename U, typename V, typename... Args> class ObjectType = std::map,
-    template<typename U, typename... Args> class ArrayType = std::vector,
-    class StringType = std::string,
-    class BooleanType = bool,
-    class NumberIntegerType = std::int64_t,
-    class NumberUnsignedType = std::uint64_t,
-    class NumberFloatType = double,
-    template<typename U> class AllocatorType = std::allocator,
-    template<typename T, typename SFINAE = void> class JSONSerializer = adl_serializer
-    >
-class basic_json
-{
-  private:
-    template<detail::value_t> friend struct detail::external_constructor;
-    /// workaround type for MSVC
-    using basic_json_t = basic_json<ObjectType, ArrayType, StringType,
-          BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType,
-          AllocatorType, JSONSerializer>;
+    /// input adapter for array
+    template<class T, std::size_t N>
+    input_adapter(T (&array)[N])
+        : input_adapter(std::begin(array), std::end(array)) {}
 
-  public:
-    using value_t = detail::value_t;
-    // forward declarations
-    template<typename U> class iter_impl;
-    template<typename Base> class json_reverse_iterator;
-    class json_pointer;
-    template<typename T, typename SFINAE>
-    using json_serializer = JSONSerializer<T, SFINAE>;
+    /// input adapter for contiguous container
+    template<class ContiguousContainer, typename
+             std::enable_if<not std::is_pointer<ContiguousContainer>::value and
+                            std::is_base_of<std::random_access_iterator_tag, typename std::iterator_traits<decltype(std::begin(std::declval<ContiguousContainer const>()))>::iterator_category>::value,
+                            int>::type = 0>
+    input_adapter(const ContiguousContainer& c)
+        : input_adapter(std::begin(c), std::end(c)) {}
 
+    operator input_adapter_t()
+    {
+        return ia;
+    }
 
-    ////////////////
-    // exceptions //
-    ////////////////
+  private:
+    /// the actual adapter
+    input_adapter_t ia = nullptr;
+};
 
-    /// @name exceptions
-    /// Classes to implement user-defined exceptions.
-    /// @{
+//////////////////////
+// lexer and parser //
+//////////////////////
 
-    /// @copydoc detail::exception
-    using exception = detail::exception;
-    /// @copydoc detail::parse_error
-    using parse_error = detail::parse_error;
-    /// @copydoc detail::invalid_iterator
-    using invalid_iterator = detail::invalid_iterator;
-    /// @copydoc detail::type_error
-    using type_error = detail::type_error;
-    /// @copydoc detail::out_of_range
-    using out_of_range = detail::out_of_range;
-    /// @copydoc detail::other_error
-    using other_error = detail::other_error;
+/*!
+@brief lexical analysis
 
-    /// @}
+This class organizes the lexical analysis during JSON deserialization.
+*/
+template<typename BasicJsonType>
+class lexer
+{
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
 
+  public:
+    /// token types for the parser
+    enum class token_type
+    {
+        uninitialized,    ///< indicating the scanner is uninitialized
+        literal_true,     ///< the `true` literal
+        literal_false,    ///< the `false` literal
+        literal_null,     ///< the `null` literal
+        value_string,     ///< a string -- use get_string() for actual value
+        value_unsigned,   ///< an unsigned integer -- use get_number_unsigned() for actual value
+        value_integer,    ///< a signed integer -- use get_number_integer() for actual value
+        value_float,      ///< an floating point number -- use get_number_float() for actual value
+        begin_array,      ///< the character for array begin `[`
+        begin_object,     ///< the character for object begin `{`
+        end_array,        ///< the character for array end `]`
+        end_object,       ///< the character for object end `}`
+        name_separator,   ///< the name separator `:`
+        value_separator,  ///< the value separator `,`
+        parse_error,      ///< indicating a parse error
+        end_of_input,     ///< indicating the end of the input buffer
+        literal_or_value  ///< a literal or the begin of a value (only for diagnostics)
+    };
 
+    /// return name of values of type token_type (only used for errors)
+    static const char* token_type_name(const token_type t) noexcept
+    {
+        switch (t)
+        {
+            case token_type::uninitialized:
+                return "<uninitialized>";
+            case token_type::literal_true:
+                return "true literal";
+            case token_type::literal_false:
+                return "false literal";
+            case token_type::literal_null:
+                return "null literal";
+            case token_type::value_string:
+                return "string literal";
+            case lexer::token_type::value_unsigned:
+            case lexer::token_type::value_integer:
+            case lexer::token_type::value_float:
+                return "number literal";
+            case token_type::begin_array:
+                return "'['";
+            case token_type::begin_object:
+                return "'{'";
+            case token_type::end_array:
+                return "']'";
+            case token_type::end_object:
+                return "'}'";
+            case token_type::name_separator:
+                return "':'";
+            case token_type::value_separator:
+                return "','";
+            case token_type::parse_error:
+                return "<parse error>";
+            case token_type::end_of_input:
+                return "end of input";
+            case token_type::literal_or_value:
+                return "'[', '{', or a literal";
+            default: // catch non-enum values
+                return "unknown token"; // LCOV_EXCL_LINE
+        }
+    }
+
+    explicit lexer(detail::input_adapter_t adapter)
+        : ia(std::move(adapter)), decimal_point_char(get_decimal_point()) {}
+
+    // delete because of pointer members
+    lexer(const lexer&) = delete;
+    lexer& operator=(lexer&) = delete;
+
+  private:
     /////////////////////
-    // container types //
+    // locales
     /////////////////////
 
-    /// @name container types
-    /// The canonic container types to use @ref basic_json like any other STL
-    /// container.
-    /// @{
-
-    /// the type of elements in a basic_json container
-    using value_type = basic_json;
+    /// return the locale-dependent decimal point
+    static char get_decimal_point() noexcept
+    {
+        const auto loc = localeconv();
+        assert(loc != nullptr);
+        return (loc->decimal_point == nullptr) ? '.' : *(loc->decimal_point);
+    }
 
-    /// the type of an element reference
-    using reference = value_type&;
-    /// the type of an element const reference
-    using const_reference = const value_type&;
+    /////////////////////
+    // scan functions
+    /////////////////////
 
-    /// a type to represent differences between iterators
-    using difference_type = std::ptrdiff_t;
-    /// a type to represent container sizes
-    using size_type = std::size_t;
+    /*!
+    @brief get codepoint from 4 hex characters following `\u`
 
-    /// the allocator type
-    using allocator_type = AllocatorType<basic_json>;
+    For input "\u c1 c2 c3 c4" the codepoint is:
+      (c1 * 0x1000) + (c2 * 0x0100) + (c3 * 0x0010) + c4
+    = (c1 << 12) + (c2 << 8) + (c3 << 4) + (c4 << 0)
 
-    /// the type of an element pointer
-    using pointer = typename std::allocator_traits<allocator_type>::pointer;
-    /// the type of an element const pointer
-    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
+    Furthermore, the possible characters '0'..'9', 'A'..'F', and 'a'..'f'
+    must be converted to the integers 0x0..0x9, 0xA..0xF, 0xA..0xF, resp. The
+    conversion is done by subtracting the offset (0x30, 0x37, and 0x57)
+    between the ASCII value of the character and the desired integer value.
 
-    /// an iterator for a basic_json container
-    using iterator = iter_impl<basic_json>;
-    /// a const iterator for a basic_json container
-    using const_iterator = iter_impl<const basic_json>;
-    /// a reverse iterator for a basic_json container
-    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
-    /// a const reverse iterator for a basic_json container
-    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;
+    @return codepoint (0x0000..0xFFFF) or -1 in case of an error (e.g. EOF or
+            non-hex character)
+    */
+    int get_codepoint()
+    {
+        // this function only makes sense after reading `\u`
+        assert(current == 'u');
+        int codepoint = 0;
 
-    /// @}
+        const auto factors = { 12, 8, 4, 0 };
+        for (const auto factor : factors)
+        {
+            get();
 
+            if (current >= '0' and current <= '9')
+            {
+                codepoint += ((current - 0x30) << factor);
+            }
+            else if (current >= 'A' and current <= 'F')
+            {
+                codepoint += ((current - 0x37) << factor);
+            }
+            else if (current >= 'a' and current <= 'f')
+            {
+                codepoint += ((current - 0x57) << factor);
+            }
+            else
+            {
+                return -1;
+            }
+        }
 
-    /*!
-    @brief returns the allocator associated with the container
-    */
-    static allocator_type get_allocator()
-    {
-        return allocator_type();
+        assert(0x0000 <= codepoint and codepoint <= 0xFFFF);
+        return codepoint;
     }
 
     /*!
-    @brief returns version information on the library
+    @brief check if the next byte(s) are inside a given range
 
-    This function returns a JSON object with information about the library,
-    including the version number and information on the platform and compiler.
-
-    @return JSON object holding version information
-    key         | description
-    ----------- | ---------------
-    `compiler`  | Information on the used compiler. It is an object with the following keys: `c++` (the used C++ standard), `family` (the compiler family; possible values are `clang`, `icc`, `gcc`, `ilecpp`, `msvc`, `pgcpp`, `sunpro`, and `unknown`), and `version` (the compiler version).
-    `copyright` | The copyright line for the library as string.
-    `name`      | The name of the library as string.
-    `platform`  | The used platform as string. Possible values are `win32`, `linux`, `apple`, `unix`, and `unknown`.
-    `url`       | The URL of the project as string.
-    `version`   | The version of the library. It is an object with the following keys: `major`, `minor`, and `patch` as defined by [Semantic Versioning](http://semver.org), and `string` (the version string).
+    Adds the current byte and, for each passed range, reads a new byte and
+    checks if it is inside the range. If a violation was detected, set up an
+    error message and return false. Otherwise, return true.
 
-    @liveexample{The following code shows an example output of the `meta()`
-    function.,meta}
+    @param[in] ranges  list of integers; interpreted as list of pairs of
+                       inclusive lower and upper bound, respectively
 
-    @complexity Constant.
+    @pre The passed list @a ranges must have 2, 4, or 6 elements; that is,
+         1, 2, or 3 pairs. This precondition is enforced by an assertion.
 
-    @since 2.1.0
+    @return true if and only if no range violation was detected
     */
-    static basic_json meta()
+    bool next_byte_in_range(std::initializer_list<int> ranges)
     {
-        basic_json result;
+        assert(ranges.size() == 2 or ranges.size() == 4 or ranges.size() == 6);
+        add(current);
 
-        result["copyright"] = "(C) 2013-2017 Niels Lohmann";
-        result["name"] = "JSON for Modern C++";
-        result["url"] = "https://github.com/nlohmann/json";
-        result["version"] =
+        for (auto range = ranges.begin(); range != ranges.end(); ++range)
         {
-            {"string", "2.1.1"}, {"major", 2}, {"minor", 1}, {"patch", 1}
-        };
-
-#ifdef _WIN32
-        result["platform"] = "win32";
-#elif defined __linux__
-        result["platform"] = "linux";
-#elif defined __APPLE__
-        result["platform"] = "apple";
-#elif defined __unix__
-        result["platform"] = "unix";
-#else
-        result["platform"] = "unknown";
-#endif
-
-#if defined(__clang__)
-        result["compiler"] = {{"family", "clang"}, {"version", __clang_version__}};
-#elif defined(__ICC) || defined(__INTEL_COMPILER)
-        result["compiler"] = {{"family", "icc"}, {"version", __INTEL_COMPILER}};
-#elif defined(__GNUC__) || defined(__GNUG__)
-        result["compiler"] = {{"family", "gcc"}, {"version", std::to_string(__GNUC__) + "." + std::to_string(__GNUC_MINOR__) + "." + std::to_string(__GNUC_PATCHLEVEL__)}};
-#elif defined(__HP_cc) || defined(__HP_aCC)
-        result["compiler"] = "hp"
-#elif defined(__IBMCPP__)
-        result["compiler"] = {{"family", "ilecpp"}, {"version", __IBMCPP__}};
-#elif defined(_MSC_VER)
-        result["compiler"] = {{"family", "msvc"}, {"version", _MSC_VER}};
-#elif defined(__PGI)
-        result["compiler"] = {{"family", "pgcpp"}, {"version", __PGI}};
-#elif defined(__SUNPRO_CC)
-        result["compiler"] = {{"family", "sunpro"}, {"version", __SUNPRO_CC}};
-#else
-        result["compiler"] = {{"family", "unknown"}, {"version", "unknown"}};
-#endif
+            get();
+            if (JSON_LIKELY(*range <= current and current <= *(++range)))
+            {
+                add(current);
+            }
+            else
+            {
+                error_message = "invalid string: ill-formed UTF-8 byte";
+                return false;
+            }
+        }
 
-#ifdef __cplusplus
-        result["compiler"]["c++"] = std::to_string(__cplusplus);
-#else
-        result["compiler"]["c++"] = "unknown";
-#endif
-        return result;
+        return true;
     }
 
-
-    ///////////////////////////
-    // JSON value data types //
-    ///////////////////////////
-
-    /// @name JSON value data types
-    /// The data types to store a JSON value. These types are derived from
-    /// the template arguments passed to class @ref basic_json.
-    /// @{
-
     /*!
-    @brief a type for an object
+    @brief scan a string literal
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
-    > An object is an unordered collection of zero or more name/value pairs,
-    > where a name is a string and a value is a string, number, boolean, null,
-    > object, or array.
+    This function scans a string according to Sect. 7 of RFC 7159. While
+    scanning, bytes are escaped and copied into buffer yytext. Then the function
+    returns successfully, yytext is *not* null-terminated (as it may contain \0
+    bytes), and yytext.size() is the number of bytes in the string.
 
-    To store objects in C++, a type is defined by the template parameters
-    described below.
+    @return token_type::value_string if string could be successfully scanned,
+            token_type::parse_error otherwise
 
-    @tparam ObjectType  the container to store objects (e.g., `std::map` or
-    `std::unordered_map`)
-    @tparam StringType the type of the keys or names (e.g., `std::string`).
-    The comparison function `std::less<StringType>` is used to order elements
-    inside the container.
-    @tparam AllocatorType the allocator to use for objects (e.g.,
-    `std::allocator`)
+    @note In case of errors, variable error_message contains a textual
+          description.
+    */
+    token_type scan_string()
+    {
+        // reset yytext (ignore opening quote)
+        reset();
 
-    #### Default type
+        // we entered the function by reading an open quote
+        assert(current == '\"');
 
-    With the default values for @a ObjectType (`std::map`), @a StringType
-    (`std::string`), and @a AllocatorType (`std::allocator`), the default
-    value for @a object_t is:
+        while (true)
+        {
+            // get next character
+            switch (get())
+            {
+                // end of file while parsing string
+                case std::char_traits<char>::eof():
+                {
+                    error_message = "invalid string: missing closing quote";
+                    return token_type::parse_error;
+                }
 
-    @code {.cpp}
-    std::map<
-      std::string, // key_type
-      basic_json, // value_type
-      std::less<std::string>, // key_compare
-      std::allocator<std::pair<const std::string, basic_json>> // allocator_type
-    >
-    @endcode
-
-    #### Behavior
+                // closing quote
+                case '\"':
+                {
+                    return token_type::value_string;
+                }
 
-    The choice of @a object_t influences the behavior of the JSON class. With
-    the default type, objects have the following behavior:
+                // escapes
+                case '\\':
+                {
+                    switch (get())
+                    {
+                        // quotation mark
+                        case '\"':
+                            add('\"');
+                            break;
+                        // reverse solidus
+                        case '\\':
+                            add('\\');
+                            break;
+                        // solidus
+                        case '/':
+                            add('/');
+                            break;
+                        // backspace
+                        case 'b':
+                            add('\b');
+                            break;
+                        // form feed
+                        case 'f':
+                            add('\f');
+                            break;
+                        // line feed
+                        case 'n':
+                            add('\n');
+                            break;
+                        // carriage return
+                        case 'r':
+                            add('\r');
+                            break;
+                        // tab
+                        case 't':
+                            add('\t');
+                            break;
 
-    - When all names are unique, objects will be interoperable in the sense
-      that all software implementations receiving that object will agree on
-      the name-value mappings.
-    - When the names within an object are not unique, later stored name/value
-      pairs overwrite previously stored name/value pairs, leaving the used
-      names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will
-      be treated as equal and both stored as `{"key": 1}`.
-    - Internally, name/value pairs are stored in lexicographical order of the
-      names. Objects will also be serialized (see @ref dump) in this order.
-      For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored
-      and serialized as `{"a": 2, "b": 1}`.
-    - When comparing objects, the order of the name/value pairs is irrelevant.
-      This makes objects interoperable in the sense that they will not be
-      affected by these differences. For instance, `{"b": 1, "a": 2}` and
-      `{"a": 2, "b": 1}` will be treated as equal.
+                        // unicode escapes
+                        case 'u':
+                        {
+                            const int codepoint1 = get_codepoint();
+                            int codepoint = codepoint1; // start with codepoint1
 
-    #### Limits
+                            if (JSON_UNLIKELY(codepoint1 == -1))
+                            {
+                                error_message = "invalid string: '\\u' must be followed by 4 hex digits";
+                                return token_type::parse_error;
+                            }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the maximum depth of nesting.
+                            // check if code point is a high surrogate
+                            if (0xD800 <= codepoint1 and codepoint1 <= 0xDBFF)
+                            {
+                                // expect next \uxxxx entry
+                                if (JSON_LIKELY(get() == '\\' and get() == 'u'))
+                                {
+                                    const int codepoint2 = get_codepoint();
+
+                                    if (JSON_UNLIKELY(codepoint2 == -1))
+                                    {
+                                        error_message = "invalid string: '\\u' must be followed by 4 hex digits";
+                                        return token_type::parse_error;
+                                    }
+
+                                    // check if codepoint2 is a low surrogate
+                                    if (JSON_LIKELY(0xDC00 <= codepoint2 and codepoint2 <= 0xDFFF))
+                                    {
+                                        // overwrite codepoint
+                                        codepoint =
+                                            // high surrogate occupies the most significant 22 bits
+                                            (codepoint1 << 10)
+                                            // low surrogate occupies the least significant 15 bits
+                                            + codepoint2
+                                            // there is still the 0xD800, 0xDC00 and 0x10000 noise
+                                            // in the result so we have to subtract with:
+                                            // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
+                                            - 0x35FDC00;
+                                    }
+                                    else
+                                    {
+                                        error_message = "invalid string: surrogate U+DC00..U+DFFF must be followed by U+DC00..U+DFFF";
+                                        return token_type::parse_error;
+                                    }
+                                }
+                                else
+                                {
+                                    error_message = "invalid string: surrogate U+DC00..U+DFFF must be followed by U+DC00..U+DFFF";
+                                    return token_type::parse_error;
+                                }
+                            }
+                            else
+                            {
+                                if (JSON_UNLIKELY(0xDC00 <= codepoint1 and codepoint1 <= 0xDFFF))
+                                {
+                                    error_message = "invalid string: surrogate U+DC00..U+DFFF must follow U+D800..U+DBFF";
+                                    return token_type::parse_error;
+                                }
+                            }
 
-    In this class, the object's limit of nesting is not constraint explicitly.
-    However, a maximum depth of nesting may be introduced by the compiler or
-    runtime environment. A theoretical limit can be queried by calling the
-    @ref max_size function of a JSON object.
+                            // result of the above calculation yields a proper codepoint
+                            assert(0x00 <= codepoint and codepoint <= 0x10FFFF);
 
-    #### Storage
+                            // translate codepoint into bytes
+                            if (codepoint < 0x80)
+                            {
+                                // 1-byte characters: 0xxxxxxx (ASCII)
+                                add(codepoint);
+                            }
+                            else if (codepoint <= 0x7FF)
+                            {
+                                // 2-byte characters: 110xxxxx 10xxxxxx
+                                add(0xC0 | (codepoint >> 6));
+                                add(0x80 | (codepoint & 0x3F));
+                            }
+                            else if (codepoint <= 0xFFFF)
+                            {
+                                // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
+                                add(0xE0 | (codepoint >> 12));
+                                add(0x80 | ((codepoint >> 6) & 0x3F));
+                                add(0x80 | (codepoint & 0x3F));
+                            }
+                            else
+                            {
+                                // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+                                add(0xF0 | (codepoint >> 18));
+                                add(0x80 | ((codepoint >> 12) & 0x3F));
+                                add(0x80 | ((codepoint >> 6) & 0x3F));
+                                add(0x80 | (codepoint & 0x3F));
+                            }
 
-    Objects are stored as pointers in a @ref basic_json type. That is, for any
-    access to object values, a pointer of type `object_t*` must be
-    dereferenced.
+                            break;
+                        }
 
-    @sa @ref array_t -- type for an array value
+                        // other characters after escape
+                        default:
+                            error_message = "invalid string: forbidden character after backslash";
+                            return token_type::parse_error;
+                    }
 
-    @since version 1.0.0
+                    break;
+                }
 
-    @note The order name/value pairs are added to the object is *not*
-    preserved by the library. Therefore, iterating an object may return
-    name/value pairs in a different order than they were originally stored. In
-    fact, keys will be traversed in alphabetical order as `std::map` with
-    `std::less` is used by default. Please note this behavior conforms to [RFC
-    7159](http://rfc7159.net/rfc7159), because any order implements the
-    specified "unordered" nature of JSON objects.
-    */
-    using object_t = ObjectType<StringType,
-          basic_json,
-          std::less<StringType>,
-          AllocatorType<std::pair<const StringType,
-          basic_json>>>;
+                // invalid control characters
+                case 0x00:
+                case 0x01:
+                case 0x02:
+                case 0x03:
+                case 0x04:
+                case 0x05:
+                case 0x06:
+                case 0x07:
+                case 0x08:
+                case 0x09:
+                case 0x0A:
+                case 0x0B:
+                case 0x0C:
+                case 0x0D:
+                case 0x0E:
+                case 0x0F:
+                case 0x10:
+                case 0x11:
+                case 0x12:
+                case 0x13:
+                case 0x14:
+                case 0x15:
+                case 0x16:
+                case 0x17:
+                case 0x18:
+                case 0x19:
+                case 0x1A:
+                case 0x1B:
+                case 0x1C:
+                case 0x1D:
+                case 0x1E:
+                case 0x1F:
+                {
+                    error_message = "invalid string: control character must be escaped";
+                    return token_type::parse_error;
+                }
+
+                // U+0020..U+007F (except U+0022 (quote) and U+005C (backspace))
+                case 0x20:
+                case 0x21:
+                case 0x23:
+                case 0x24:
+                case 0x25:
+                case 0x26:
+                case 0x27:
+                case 0x28:
+                case 0x29:
+                case 0x2A:
+                case 0x2B:
+                case 0x2C:
+                case 0x2D:
+                case 0x2E:
+                case 0x2F:
+                case 0x30:
+                case 0x31:
+                case 0x32:
+                case 0x33:
+                case 0x34:
+                case 0x35:
+                case 0x36:
+                case 0x37:
+                case 0x38:
+                case 0x39:
+                case 0x3A:
+                case 0x3B:
+                case 0x3C:
+                case 0x3D:
+                case 0x3E:
+                case 0x3F:
+                case 0x40:
+                case 0x41:
+                case 0x42:
+                case 0x43:
+                case 0x44:
+                case 0x45:
+                case 0x46:
+                case 0x47:
+                case 0x48:
+                case 0x49:
+                case 0x4A:
+                case 0x4B:
+                case 0x4C:
+                case 0x4D:
+                case 0x4E:
+                case 0x4F:
+                case 0x50:
+                case 0x51:
+                case 0x52:
+                case 0x53:
+                case 0x54:
+                case 0x55:
+                case 0x56:
+                case 0x57:
+                case 0x58:
+                case 0x59:
+                case 0x5A:
+                case 0x5B:
+                case 0x5D:
+                case 0x5E:
+                case 0x5F:
+                case 0x60:
+                case 0x61:
+                case 0x62:
+                case 0x63:
+                case 0x64:
+                case 0x65:
+                case 0x66:
+                case 0x67:
+                case 0x68:
+                case 0x69:
+                case 0x6A:
+                case 0x6B:
+                case 0x6C:
+                case 0x6D:
+                case 0x6E:
+                case 0x6F:
+                case 0x70:
+                case 0x71:
+                case 0x72:
+                case 0x73:
+                case 0x74:
+                case 0x75:
+                case 0x76:
+                case 0x77:
+                case 0x78:
+                case 0x79:
+                case 0x7A:
+                case 0x7B:
+                case 0x7C:
+                case 0x7D:
+                case 0x7E:
+                case 0x7F:
+                {
+                    add(current);
+                    break;
+                }
 
-    /*!
-    @brief a type for an array
+                // U+0080..U+07FF: bytes C2..DF 80..BF
+                case 0xC2:
+                case 0xC3:
+                case 0xC4:
+                case 0xC5:
+                case 0xC6:
+                case 0xC7:
+                case 0xC8:
+                case 0xC9:
+                case 0xCA:
+                case 0xCB:
+                case 0xCC:
+                case 0xCD:
+                case 0xCE:
+                case 0xCF:
+                case 0xD0:
+                case 0xD1:
+                case 0xD2:
+                case 0xD3:
+                case 0xD4:
+                case 0xD5:
+                case 0xD6:
+                case 0xD7:
+                case 0xD8:
+                case 0xD9:
+                case 0xDA:
+                case 0xDB:
+                case 0xDC:
+                case 0xDD:
+                case 0xDE:
+                case 0xDF:
+                {
+                    if (JSON_UNLIKELY(not next_byte_in_range({0x80, 0xBF})))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
-    > An array is an ordered sequence of zero or more values.
+                // U+0800..U+0FFF: bytes E0 A0..BF 80..BF
+                case 0xE0:
+                {
+                    if (JSON_UNLIKELY(not (next_byte_in_range({0xA0, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
 
-    To store objects in C++, a type is defined by the template parameters
-    explained below.
+                // U+1000..U+CFFF: bytes E1..EC 80..BF 80..BF
+                // U+E000..U+FFFF: bytes EE..EF 80..BF 80..BF
+                case 0xE1:
+                case 0xE2:
+                case 0xE3:
+                case 0xE4:
+                case 0xE5:
+                case 0xE6:
+                case 0xE7:
+                case 0xE8:
+                case 0xE9:
+                case 0xEA:
+                case 0xEB:
+                case 0xEC:
+                case 0xEE:
+                case 0xEF:
+                {
+                    if (JSON_UNLIKELY(not (next_byte_in_range({0x80, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
 
-    @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
-    `std::list`)
-    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
+                // U+D000..U+D7FF: bytes ED 80..9F 80..BF
+                case 0xED:
+                {
+                    if (JSON_UNLIKELY(not (next_byte_in_range({0x80, 0x9F, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
 
-    #### Default type
+                // U+10000..U+3FFFF F0 90..BF 80..BF 80..BF
+                case 0xF0:
+                {
+                    if (JSON_UNLIKELY(not (next_byte_in_range({0x90, 0xBF, 0x80, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
 
-    With the default values for @a ArrayType (`std::vector`) and @a
-    AllocatorType (`std::allocator`), the default value for @a array_t is:
+                // U+40000..U+FFFFF F1..F3 80..BF 80..BF 80..BF
+                case 0xF1:
+                case 0xF2:
+                case 0xF3:
+                {
+                    if (JSON_UNLIKELY(not (next_byte_in_range({0x80, 0xBF, 0x80, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
 
-    @code {.cpp}
-    std::vector<
-      basic_json, // value_type
-      std::allocator<basic_json> // allocator_type
-    >
-    @endcode
+                // U+100000..U+10FFFF F4 80..8F 80..BF 80..BF
+                case 0xF4:
+                {
+                    if (JSON_UNLIKELY(not (next_byte_in_range({0x80, 0x8F, 0x80, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
 
-    #### Limits
+                // remaining bytes (80..C1 and F5..FF) are ill-formed
+                default:
+                {
+                    error_message = "invalid string: ill-formed UTF-8 byte";
+                    return token_type::parse_error;
+                }
+            }
+        }
+    }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the maximum depth of nesting.
+    static void strtof(float& f, const char* str, char** endptr) noexcept
+    {
+        f = std::strtof(str, endptr);
+    }
 
-    In this class, the array's limit of nesting is not constraint explicitly.
-    However, a maximum depth of nesting may be introduced by the compiler or
-    runtime environment. A theoretical limit can be queried by calling the
-    @ref max_size function of a JSON array.
+    static void strtof(double& f, const char* str, char** endptr) noexcept
+    {
+        f = std::strtod(str, endptr);
+    }
 
-    #### Storage
+    static void strtof(long double& f, const char* str, char** endptr) noexcept
+    {
+        f = std::strtold(str, endptr);
+    }
 
-    Arrays are stored as pointers in a @ref basic_json type. That is, for any
-    access to array values, a pointer of type `array_t*` must be dereferenced.
+    /*!
+    @brief scan a number literal
 
-    @sa @ref object_t -- type for an object value
+    This function scans a string according to Sect. 6 of RFC 7159.
 
-    @since version 1.0.0
-    */
-    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
+    The function is realized with a deterministic finite state machine derived
+    from the grammar described in RFC 7159. Starting in state "init", the
+    input is read and used to determined the next state. Only state "done"
+    accepts the number. State "error" is a trap state to model errors. In the
+    table below, "anything" means any character but the ones listed before.
 
-    /*!
-    @brief a type for a string
+    state    | 0        | 1-9      | e E      | +       | -       | .        | anything
+    ---------|----------|----------|----------|---------|---------|----------|-----------
+    init     | zero     | any1     | [error]  | [error] | minus   | [error]  | [error]
+    minus    | zero     | any1     | [error]  | [error] | [error] | [error]  | [error]
+    zero     | done     | done     | exponent | done    | done    | decimal1 | done
+    any1     | any1     | any1     | exponent | done    | done    | decimal1 | done
+    decimal1 | decimal2 | [error]  | [error]  | [error] | [error] | [error]  | [error]
+    decimal2 | decimal2 | decimal2 | exponent | done    | done    | done     | done
+    exponent | any2     | any2     | [error]  | sign    | sign    | [error]  | [error]
+    sign     | any2     | any2     | [error]  | [error] | [error] | [error]  | [error]
+    any2     | any2     | any2     | done     | done    | done    | done     | done
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
-    > A string is a sequence of zero or more Unicode characters.
+    The state machine is realized with one label per state (prefixed with
+    "scan_number_") and `goto` statements between them. The state machine
+    contains cycles, but any cycle can be left when EOF is read. Therefore,
+    the function is guaranteed to terminate.
 
-    To store objects in C++, a type is defined by the template parameter
-    described below. Unicode values are split by the JSON class into
-    byte-sized characters during deserialization.
+    During scanning, the read bytes are stored in yytext. This string is
+    then converted to a signed integer, an unsigned integer, or a
+    floating-point number.
 
-    @tparam StringType  the container to store strings (e.g., `std::string`).
-    Note this container is used for keys/names in objects, see @ref object_t.
+    @return token_type::value_unsigned, token_type::value_integer, or
+            token_type::value_float if number could be successfully scanned,
+            token_type::parse_error otherwise
 
-    #### Default type
+    @note The scanner is independent of the current locale. Internally, the
+          locale's decimal point is used instead of `.` to work with the
+          locale-dependent converters.
+    */
+    token_type scan_number()
+    {
+        // reset yytext to store the number's bytes
+        reset();
 
-    With the default values for @a StringType (`std::string`), the default
-    value for @a string_t is:
+        // the type of the parsed number; initially set to unsigned; will be
+        // changed if minus sign, decimal point or exponent is read
+        token_type number_type = token_type::value_unsigned;
 
-    @code {.cpp}
-    std::string
-    @endcode
+        // state (init): we just found out we need to scan a number
+        switch (current)
+        {
+            case '-':
+            {
+                add(current);
+                goto scan_number_minus;
+            }
 
-    #### Encoding
+            case '0':
+            {
+                add(current);
+                goto scan_number_zero;
+            }
 
-    Strings are stored in UTF-8 encoding. Therefore, functions like
-    `std::string::size()` or `std::string::length()` return the number of
-    bytes in the string rather than the number of characters or glyphs.
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any1;
+            }
 
-    #### String comparison
+            default:
+            {
+                // all other characters are rejected outside scan_number()
+                assert(false); // LCOV_EXCL_LINE
+            }
+        }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
-    > Software implementations are typically required to test names of object
-    > members for equality. Implementations that transform the textual
-    > representation into sequences of Unicode code units and then perform the
-    > comparison numerically, code unit by code unit, are interoperable in the
-    > sense that implementations will agree in all cases on equality or
-    > inequality of two strings. For example, implementations that compare
-    > strings with escaped characters unconverted may incorrectly find that
-    > `"a\\b"` and `"a\u005Cb"` are not equal.
+scan_number_minus:
+        // state: we just parsed a leading minus sign
+        number_type = token_type::value_integer;
+        switch (get())
+        {
+            case '0':
+            {
+                add(current);
+                goto scan_number_zero;
+            }
 
-    This implementation is interoperable as it does compare strings code unit
-    by code unit.
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any1;
+            }
 
-    #### Storage
+            default:
+            {
+                error_message = "invalid number; expected digit after '-'";
+                return token_type::parse_error;
+            }
+        }
 
-    String values are stored as pointers in a @ref basic_json type. That is,
-    for any access to string values, a pointer of type `string_t*` must be
-    dereferenced.
+scan_number_zero:
+        // state: we just parse a zero (maybe with a leading minus sign)
+        switch (get())
+        {
+            case '.':
+            {
+                add(decimal_point_char);
+                goto scan_number_decimal1;
+            }
 
-    @since version 1.0.0
-    */
-    using string_t = StringType;
+            case 'e':
+            case 'E':
+            {
+                add(current);
+                goto scan_number_exponent;
+            }
 
-    /*!
-    @brief a type for a boolean
+            default:
+                goto scan_number_done;
+        }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
-    type which differentiates the two literals `true` and `false`.
+scan_number_any1:
+        // state: we just parsed a number 0-9 (maybe with a leading minus sign)
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any1;
+            }
 
-    To store objects in C++, a type is defined by the template parameter @a
-    BooleanType which chooses the type to use.
+            case '.':
+            {
+                add(decimal_point_char);
+                goto scan_number_decimal1;
+            }
 
-    #### Default type
+            case 'e':
+            case 'E':
+            {
+                add(current);
+                goto scan_number_exponent;
+            }
 
-    With the default values for @a BooleanType (`bool`), the default value for
-    @a boolean_t is:
+            default:
+                goto scan_number_done;
+        }
 
-    @code {.cpp}
-    bool
-    @endcode
+scan_number_decimal1:
+        // state: we just parsed a decimal point
+        number_type = token_type::value_float;
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_decimal2;
+            }
 
-    #### Storage
+            default:
+            {
+                error_message = "invalid number; expected digit after '.'";
+                return token_type::parse_error;
+            }
+        }
 
-    Boolean values are stored directly inside a @ref basic_json type.
+scan_number_decimal2:
+        // we just parsed at least one number after a decimal point
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_decimal2;
+            }
 
-    @since version 1.0.0
-    */
-    using boolean_t = BooleanType;
+            case 'e':
+            case 'E':
+            {
+                add(current);
+                goto scan_number_exponent;
+            }
 
-    /*!
-    @brief a type for a number (integer)
+            default:
+                goto scan_number_done;
+        }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
+scan_number_exponent:
+        // we just parsed an exponent
+        number_type = token_type::value_float;
+        switch (get())
+        {
+            case '+':
+            case '-':
+            {
+                add(current);
+                goto scan_number_sign;
+            }
 
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any2;
+            }
 
-    To store integer numbers in C++, a type is defined by the template
-    parameter @a NumberIntegerType which chooses the type to use.
+            default:
+            {
+                error_message =
+                    "invalid number; expected '+', '-', or digit after exponent";
+                return token_type::parse_error;
+            }
+        }
 
-    #### Default type
+scan_number_sign:
+        // we just parsed an exponent sign
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any2;
+            }
 
-    With the default values for @a NumberIntegerType (`int64_t`), the default
-    value for @a number_integer_t is:
+            default:
+            {
+                error_message = "invalid number; expected digit after exponent sign";
+                return token_type::parse_error;
+            }
+        }
 
-    @code {.cpp}
-    int64_t
-    @endcode
+scan_number_any2:
+        // we just parsed a number after the exponent or exponent sign
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any2;
+            }
 
-    #### Default behavior
+            default:
+                goto scan_number_done;
+        }
 
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in integer literals lead to an interpretation as octal
-      number. Internally, the value will be stored as decimal number. For
-      instance, the C++ integer literal `010` will be serialized to `8`.
-      During deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
+scan_number_done:
+        // unget the character after the number (we only read it to know that
+        // we are done scanning a number)
+        unget();
 
-    #### Limits
+        char* endptr = nullptr;
+        errno = 0;
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the range and precision of numbers.
+        // try to parse integers first and fall back to floats
+        if (number_type == token_type::value_unsigned)
+        {
+            const auto x = std::strtoull(yytext.data(), &endptr, 10);
 
-    When the default type is used, the maximal integer number that can be
-    stored is `9223372036854775807` (INT64_MAX) and the minimal integer number
-    that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers
-    that are out of range will yield over/underflow when used in a
-    constructor. During deserialization, too large or small integer numbers
-    will be automatically be stored as @ref number_unsigned_t or @ref
-    number_float_t.
+            // we checked the number format before
+            assert(endptr == yytext.data() + yytext.size());
 
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
-    > Note that when such software is used, numbers that are integers and are
-    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
-    > that implementations will agree exactly on their numeric values.
+            if (errno == 0)
+            {
+                value_unsigned = static_cast<number_unsigned_t>(x);
+                if (value_unsigned == x)
+                {
+                    return token_type::value_unsigned;
+                }
+            }
+        }
+        else if (number_type == token_type::value_integer)
+        {
+            const auto x = std::strtoll(yytext.data(), &endptr, 10);
 
-    As this range is a subrange of the exactly supported range [INT64_MIN,
-    INT64_MAX], this class's integer type is interoperable.
+            // we checked the number format before
+            assert(endptr == yytext.data() + yytext.size());
 
-    #### Storage
+            if (errno == 0)
+            {
+                value_integer = static_cast<number_integer_t>(x);
+                if (value_integer == x)
+                {
+                    return token_type::value_integer;
+                }
+            }
+        }
 
-    Integer number values are stored directly inside a @ref basic_json type.
+        // this code is reached if we parse a floating-point number or if an
+        // integer conversion above failed
+        strtof(value_float, yytext.data(), &endptr);
 
-    @sa @ref number_float_t -- type for number values (floating-point)
+        // we checked the number format before
+        assert(endptr == yytext.data() + yytext.size());
 
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+        return token_type::value_float;
+    }
 
-    @since version 1.0.0
+    /*!
+    @param[in] literal_text  the literal text to expect
+    @param[in] length        the length of the passed literal text
+    @param[in] return_type   the token type to return on success
     */
-    using number_integer_t = NumberIntegerType;
+    token_type scan_literal(const char* literal_text, const std::size_t length,
+                            token_type return_type)
+    {
+        assert(current == literal_text[0]);
+        for (std::size_t i = 1; i < length; ++i)
+        {
+            if (JSON_UNLIKELY(get() != literal_text[i]))
+            {
+                error_message = "invalid literal";
+                return token_type::parse_error;
+            }
+        }
+        return return_type;
+    }
 
-    /*!
-    @brief a type for a number (unsigned)
+    /////////////////////
+    // input management
+    /////////////////////
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
+    /// reset yytext; current character is beginning of token
+    void reset() noexcept
+    {
+        yytext.clear();
+        token_string.clear();
+        token_string.push_back(std::char_traits<char>::to_char_type(current));
+    }
 
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
+    /*
+    @brief get next character from the input
 
-    To store unsigned integer numbers in C++, a type is defined by the
-    template parameter @a NumberUnsignedType which chooses the type to use.
+    This function provides the interface to the used input adapter. It does
+    not throw in case the input reached EOF, but returns a
+    `std::char_traits<char>::eof()` in that case.  Stores the scanned characters
+    for use in error messages.
 
-    #### Default type
+    @return character read from the input
+    */
+    std::char_traits<char>::int_type get()
+    {
+        ++chars_read;
+        current = ia->get_character();
+        if (JSON_LIKELY(current != std::char_traits<char>::eof()))
+        {
+            token_string.push_back(std::char_traits<char>::to_char_type(current));
+        }
+        return current;
+    }
 
-    With the default values for @a NumberUnsignedType (`uint64_t`), the
-    default value for @a number_unsigned_t is:
+    /// unget current character (return it again on next get)
+    void unget()
+    {
+        --chars_read;
+        if (JSON_LIKELY(current != std::char_traits<char>::eof()))
+        {
+            ia->unget_character();
+            assert(token_string.size() != 0);
+            token_string.pop_back();
+        }
+    }
 
-    @code {.cpp}
-    uint64_t
-    @endcode
+    /// add a character to yytext
+    void add(int c)
+    {
+        yytext.push_back(std::char_traits<char>::to_char_type(c));
+    }
 
-    #### Default behavior
+  public:
+    /////////////////////
+    // value getters
+    /////////////////////
 
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in integer literals lead to an interpretation as octal
-      number. Internally, the value will be stored as decimal number. For
-      instance, the C++ integer literal `010` will be serialized to `8`.
-      During deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
+    /// return integer value
+    constexpr number_integer_t get_number_integer() const noexcept
+    {
+        return value_integer;
+    }
 
-    #### Limits
+    /// return unsigned integer value
+    constexpr number_unsigned_t get_number_unsigned() const noexcept
+    {
+        return value_unsigned;
+    }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
-    > An implementation may set limits on the range and precision of numbers.
+    /// return floating-point value
+    constexpr number_float_t get_number_float() const noexcept
+    {
+        return value_float;
+    }
 
-    When the default type is used, the maximal integer number that can be
-    stored is `18446744073709551615` (UINT64_MAX) and the minimal integer
-    number that can be stored is `0`. Integer numbers that are out of range
-    will yield over/underflow when used in a constructor. During
-    deserialization, too large or small integer numbers will be automatically
-    be stored as @ref number_integer_t or @ref number_float_t.
+    /// return current string value (implicitly resets the token; useful only once)
+    std::string move_string()
+    {
+        return std::move(yytext);
+    }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
-    > Note that when such software is used, numbers that are integers and are
-    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
-    > that implementations will agree exactly on their numeric values.
+    /////////////////////
+    // diagnostics
+    /////////////////////
 
-    As this range is a subrange (when considered in conjunction with the
-    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
-    this class's integer type is interoperable.
+    /// return position of last read token
+    constexpr std::size_t get_position() const noexcept
+    {
+        return chars_read;
+    }
 
-    #### Storage
+    /// return the last read token (for errors only).  Will never contain EOF
+    /// (an arbitrary value that is not a valid char value, often -1), because
+    /// 255 may legitimately occur.  May contain NUL, which should be escaped.
+    std::string get_token_string() const
+    {
+        // escape control characters
+        std::string result;
+        for (const auto c : token_string)
+        {
+            if ('\x00' <= c and c <= '\x1F')
+            {
+                // escape control characters
+                std::stringstream ss;
+                ss << "<U+" << std::setw(4) << std::uppercase << std::setfill('0')
+                   << std::hex << static_cast<int>(c) << ">";
+                result += ss.str();
+            }
+            else
+            {
+                // add character as is
+                result.push_back(c);
+            }
+        }
 
-    Integer number values are stored directly inside a @ref basic_json type.
+        return result;
+    }
 
-    @sa @ref number_float_t -- type for number values (floating-point)
-    @sa @ref number_integer_t -- type for number values (integer)
+    /// return syntax error message
+    constexpr const char* get_error_message() const noexcept
+    {
+        return error_message;
+    }
 
-    @since version 2.0.0
-    */
-    using number_unsigned_t = NumberUnsignedType;
+    /////////////////////
+    // actual scanner
+    /////////////////////
 
-    /*!
-    @brief a type for a number (floating-point)
+    token_type scan()
+    {
+        // read next character and ignore whitespace
+        do
+        {
+            get();
+        }
+        while (current == ' ' or current == '\t' or current == '\n' or current == '\r');
+
+        switch (current)
+        {
+            // structural characters
+            case '[':
+                return token_type::begin_array;
+            case ']':
+                return token_type::end_array;
+            case '{':
+                return token_type::begin_object;
+            case '}':
+                return token_type::end_object;
+            case ':':
+                return token_type::name_separator;
+            case ',':
+                return token_type::value_separator;
+
+            // literals
+            case 't':
+                return scan_literal("true", 4, token_type::literal_true);
+            case 'f':
+                return scan_literal("false", 5, token_type::literal_false);
+            case 'n':
+                return scan_literal("null", 4, token_type::literal_null);
+
+            // string
+            case '\"':
+                return scan_string();
+
+            // number
+            case '-':
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+                return scan_number();
+
+            // end of input (the null byte is needed when parsing from
+            // string literals)
+            case '\0':
+            case std::char_traits<char>::eof():
+                return token_type::end_of_input;
+
+            // error
+            default:
+                error_message = "invalid literal";
+                return token_type::parse_error;
+        }
+    }
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
-    > The representation of numbers is similar to that used in most
-    > programming languages. A number is represented in base 10 using decimal
-    > digits. It contains an integer component that may be prefixed with an
-    > optional minus sign, which may be followed by a fraction part and/or an
-    > exponent part. Leading zeros are not allowed. (...) Numeric values that
-    > cannot be represented in the grammar below (such as Infinity and NaN)
-    > are not permitted.
+  private:
+    /// input adapter
+    detail::input_adapter_t ia = nullptr;
 
-    This description includes both integer and floating-point numbers.
-    However, C++ allows more precise storage if it is known whether the number
-    is a signed integer, an unsigned integer or a floating-point number.
-    Therefore, three different types, @ref number_integer_t, @ref
-    number_unsigned_t and @ref number_float_t are used.
+    /// the current character
+    std::char_traits<char>::int_type current = std::char_traits<char>::eof();
 
-    To store floating-point numbers in C++, a type is defined by the template
-    parameter @a NumberFloatType which chooses the type to use.
+    /// the number of characters read
+    std::size_t chars_read = 0;
 
-    #### Default type
+    /// raw input token string (for error messages)
+    std::vector<char> token_string {};
 
-    With the default values for @a NumberFloatType (`double`), the default
-    value for @a number_float_t is:
+    /// buffer for variable-length tokens (numbers, strings)
+    std::string yytext {};
 
-    @code {.cpp}
-    double
-    @endcode
+    /// a description of occurred lexer errors
+    const char* error_message = "";
 
-    #### Default behavior
+    // number values
+    number_integer_t value_integer = 0;
+    number_unsigned_t value_unsigned = 0;
+    number_float_t value_float = 0;
 
-    - The restrictions about leading zeros is not enforced in C++. Instead,
-      leading zeros in floating-point literals will be ignored. Internally,
-      the value will be stored as decimal number. For instance, the C++
-      floating-point literal `01.2` will be serialized to `1.2`. During
-      deserialization, leading zeros yield an error.
-    - Not-a-number (NaN) values will be serialized to `null`.
+    /// the decimal point
+    const char decimal_point_char = '.';
+};
 
-    #### Limits
+/*!
+@brief syntax analysis
 
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
-    > This specification allows implementations to set limits on the range and
-    > precision of numbers accepted. Since software that implements IEEE
-    > 754-2008 binary64 (double precision) numbers is generally available and
-    > widely used, good interoperability can be achieved by implementations
-    > that expect no more precision or range than these provide, in the sense
-    > that implementations will approximate JSON numbers within the expected
-    > precision.
+This class implements a recursive decent parser.
+*/
+template<typename BasicJsonType>
+class parser
+{
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using lexer_t = lexer<BasicJsonType>;
+    using token_type = typename lexer_t::token_type;
 
-    This implementation does exactly follow this approach, as it uses double
-    precision floating-point numbers. Note values smaller than
-    `-1.79769313486232e+308` and values greater than `1.79769313486232e+308`
-    will be stored as NaN internally and be serialized to `null`.
+  public:
+    enum class parse_event_t : uint8_t
+    {
+        /// the parser read `{` and started to process a JSON object
+        object_start,
+        /// the parser read `}` and finished processing a JSON object
+        object_end,
+        /// the parser read `[` and started to process a JSON array
+        array_start,
+        /// the parser read `]` and finished processing a JSON array
+        array_end,
+        /// the parser read a key of a value in an object
+        key,
+        /// the parser finished reading a JSON value
+        value
+    };
 
-    #### Storage
+    using parser_callback_t =
+        std::function<bool(int depth, parse_event_t event, BasicJsonType& parsed)>;
 
-    Floating-point number values are stored directly inside a @ref basic_json
-    type.
+    /// a parser reading from an input adapter
+    explicit parser(detail::input_adapter_t adapter,
+                    const parser_callback_t cb = nullptr,
+                    const bool allow_exceptions_ = true)
+        : callback(cb), m_lexer(adapter), allow_exceptions(allow_exceptions_)
+    {}
 
-    @sa @ref number_integer_t -- type for number values (integer)
+    /*!
+    @brief public parser interface
 
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+    @param[in] strict      whether to expect the last token to be EOF
+    @param[in,out] result  parsed JSON value
 
-    @since version 1.0.0
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
     */
-    using number_float_t = NumberFloatType;
+    void parse(const bool strict, BasicJsonType& result)
+    {
+        // read first token
+        get_token();
 
-    /// @}
+        parse_internal(true, result);
+        result.assert_invariant();
 
-  private:
+        // in strict mode, input must be completely read
+        if (strict)
+        {
+            get_token();
+            expect(token_type::end_of_input);
+        }
 
-    /// helper for exception-safe object creation
-    template<typename T, typename... Args>
-    static T* create(Args&& ... args)
-    {
-        AllocatorType<T> alloc;
-        auto deleter = [&](T * object)
+        // in case of an error, return discarded value
+        if (errored)
         {
-            alloc.deallocate(object, 1);
-        };
-        std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
-        alloc.construct(object.get(), std::forward<Args>(args)...);
-        assert(object != nullptr);
-        return object.release();
-    }
+            result = value_t::discarded;
+            return;
+        }
 
-    ////////////////////////
-    // JSON value storage //
-    ////////////////////////
+        // set top-level value to null if it was discarded by the callback
+        // function
+        if (result.is_discarded())
+        {
+            result = nullptr;
+        }
+    }
 
     /*!
-    @brief a JSON value
+    @brief public accept interface
 
-    The actual storage for a JSON value of the @ref basic_json class. This
-    union combines the different storage types for the JSON value types
-    defined in @ref value_t.
+    @param[in] strict  whether to expect the last token to be EOF
+    @return whether the input is a proper JSON text
+    */
+    bool accept(const bool strict = true)
+    {
+        // read first token
+        get_token();
 
-    JSON type | value_t type    | used type
-    --------- | --------------- | ------------------------
-    object    | object          | pointer to @ref object_t
-    array     | array           | pointer to @ref array_t
-    string    | string          | pointer to @ref string_t
-    boolean   | boolean         | @ref boolean_t
-    number    | number_integer  | @ref number_integer_t
-    number    | number_unsigned | @ref number_unsigned_t
-    number    | number_float    | @ref number_float_t
-    null      | null            | *no value is stored*
+        if (not accept_internal())
+        {
+            return false;
+        }
 
-    @note Variable-length types (objects, arrays, and strings) are stored as
-    pointers. The size of the union should not exceed 64 bits if the default
-    value types are used.
+        // strict => last token must be EOF
+        return not strict or (get_token() == token_type::end_of_input);
+    }
 
-    @since version 1.0.0
+  private:
+    /*!
+    @brief the actual parser
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
     */
-    union json_value
+    void parse_internal(bool keep, BasicJsonType& result)
     {
-        /// object (stored with pointer to save storage)
-        object_t* object;
-        /// array (stored with pointer to save storage)
-        array_t* array;
-        /// string (stored with pointer to save storage)
-        string_t* string;
-        /// boolean
-        boolean_t boolean;
-        /// number (integer)
-        number_integer_t number_integer;
-        /// number (unsigned integer)
-        number_unsigned_t number_unsigned;
-        /// number (floating-point)
-        number_float_t number_float;
+        // never parse after a parse error was detected
+        assert(not errored);
 
-        /// default constructor (for null values)
-        json_value() = default;
-        /// constructor for booleans
-        json_value(boolean_t v) noexcept : boolean(v) {}
-        /// constructor for numbers (integer)
-        json_value(number_integer_t v) noexcept : number_integer(v) {}
-        /// constructor for numbers (unsigned)
-        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
-        /// constructor for numbers (floating-point)
-        json_value(number_float_t v) noexcept : number_float(v) {}
-        /// constructor for empty values of a given type
-        json_value(value_t t)
+        // start with a discarded value
+        if (not result.is_discarded())
         {
-            switch (t)
+            result.m_value.destroy(result.m_type);
+            result.m_type = value_t::discarded;
+        }
+
+        switch (last_token)
+        {
+            case token_type::begin_object:
             {
-                case value_t::object:
+                if (keep)
                 {
-                    object = create<object_t>();
-                    break;
-                }
+                    if (callback)
+                    {
+                        keep = callback(depth++, parse_event_t::object_start, result);
+                    }
 
-                case value_t::array:
-                {
-                    array = create<array_t>();
-                    break;
+                    if (not callback or keep)
+                    {
+                        // explicitly set result to object to cope with {}
+                        result.m_type = value_t::object;
+                        result.m_value = value_t::object;
+                    }
                 }
 
-                case value_t::string:
-                {
-                    string = create<string_t>("");
-                    break;
-                }
+                // read next token
+                get_token();
 
-                case value_t::boolean:
+                // closing } -> we are done
+                if (last_token == token_type::end_object)
                 {
-                    boolean = boolean_t(false);
+                    if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
+                    {
+                        result.m_value.destroy(result.m_type);
+                        result.m_type = value_t::discarded;
+                    }
                     break;
                 }
 
-                case value_t::number_integer:
+                // parse values
+                std::string key;
+                BasicJsonType value;
+                while (true)
                 {
-                    number_integer = number_integer_t(0);
+                    // store key
+                    if (not expect(token_type::value_string))
+                    {
+                        return;
+                    }
+                    key = m_lexer.move_string();
+
+                    bool keep_tag = false;
+                    if (keep)
+                    {
+                        if (callback)
+                        {
+                            BasicJsonType k(key);
+                            keep_tag = callback(depth, parse_event_t::key, k);
+                        }
+                        else
+                        {
+                            keep_tag = true;
+                        }
+                    }
+
+                    // parse separator (:)
+                    get_token();
+                    if (not expect(token_type::name_separator))
+                    {
+                        return;
+                    }
+
+                    // parse and add value
+                    get_token();
+                    value.m_value.destroy(value.m_type);
+                    value.m_type = value_t::discarded;
+                    parse_internal(keep, value);
+
+                    if (JSON_UNLIKELY(errored))
+                    {
+                        return;
+                    }
+
+                    if (keep and keep_tag and not value.is_discarded())
+                    {
+                        result.m_value.object->emplace(std::move(key), std::move(value));
+                    }
+
+                    // comma -> next value
+                    get_token();
+                    if (last_token == token_type::value_separator)
+                    {
+                        get_token();
+                        continue;
+                    }
+
+                    // closing }
+                    if (not expect(token_type::end_object))
+                    {
+                        return;
+                    }
                     break;
                 }
 
-                case value_t::number_unsigned:
+                if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
                 {
-                    number_unsigned = number_unsigned_t(0);
-                    break;
+                    result.m_value.destroy(result.m_type);
+                    result.m_type = value_t::discarded;
                 }
+                break;
+            }
 
-                case value_t::number_float:
+            case token_type::begin_array:
+            {
+                if (keep)
                 {
-                    number_float = number_float_t(0.0);
-                    break;
+                    if (callback)
+                    {
+                        keep = callback(depth++, parse_event_t::array_start, result);
+                    }
+
+                    if (not callback or keep)
+                    {
+                        // explicitly set result to array to cope with []
+                        result.m_type = value_t::array;
+                        result.m_value = value_t::array;
+                    }
                 }
 
-                case value_t::null:
+                // read next token
+                get_token();
+
+                // closing ] -> we are done
+                if (last_token == token_type::end_array)
                 {
+                    if (callback and not callback(--depth, parse_event_t::array_end, result))
+                    {
+                        result.m_value.destroy(result.m_type);
+                        result.m_type = value_t::discarded;
+                    }
                     break;
                 }
 
-                default:
+                // parse values
+                BasicJsonType value;
+                while (true)
                 {
-                    if (t == value_t::null)
+                    // parse value
+                    value.m_value.destroy(value.m_type);
+                    value.m_type = value_t::discarded;
+                    parse_internal(keep, value);
+
+                    if (JSON_UNLIKELY(errored))
+                    {
+                        return;
+                    }
+
+                    if (keep and not value.is_discarded())
+                    {
+                        result.m_value.array->push_back(std::move(value));
+                    }
+
+                    // comma -> next value
+                    get_token();
+                    if (last_token == token_type::value_separator)
+                    {
+                        get_token();
+                        continue;
+                    }
+
+                    // closing ]
+                    if (not expect(token_type::end_array))
                     {
-                        JSON_THROW(other_error::create(500, "961c151d2e87f2686a955a9be24d316f1362bf21 2.1.1")); // LCOV_EXCL_LINE
+                        return;
                     }
                     break;
                 }
+
+                if (keep and callback and not callback(--depth, parse_event_t::array_end, result))
+                {
+                    result.m_value.destroy(result.m_type);
+                    result.m_type = value_t::discarded;
+                }
+                break;
             }
-        }
 
-        /// constructor for strings
-        json_value(const string_t& value)
-        {
-            string = create<string_t>(value);
-        }
+            case token_type::literal_null:
+            {
+                result.m_type = value_t::null;
+                break;
+            }
 
-        /// constructor for objects
-        json_value(const object_t& value)
-        {
-            object = create<object_t>(value);
-        }
+            case token_type::value_string:
+            {
+                result.m_type = value_t::string;
+                result.m_value = m_lexer.move_string();
+                break;
+            }
 
-        /// constructor for arrays
-        json_value(const array_t& value)
-        {
-            array = create<array_t>(value);
-        }
-    };
+            case token_type::literal_true:
+            {
+                result.m_type = value_t::boolean;
+                result.m_value = true;
+                break;
+            }
 
-    /*!
-    @brief checks the class invariants
+            case token_type::literal_false:
+            {
+                result.m_type = value_t::boolean;
+                result.m_value = false;
+                break;
+            }
 
-    This function asserts the class invariants. It needs to be called at the
-    end of every constructor to make sure that created objects respect the
-    invariant. Furthermore, it has to be called each time the type of a JSON
-    value is changed, because the invariant expresses a relationship between
-    @a m_type and @a m_value.
-    */
-    void assert_invariant() const
-    {
-        assert(m_type != value_t::object or m_value.object != nullptr);
-        assert(m_type != value_t::array or m_value.array != nullptr);
-        assert(m_type != value_t::string or m_value.string != nullptr);
-    }
+            case token_type::value_unsigned:
+            {
+                result.m_type = value_t::number_unsigned;
+                result.m_value = m_lexer.get_number_unsigned();
+                break;
+            }
 
-  public:
-    //////////////////////////
-    // JSON parser callback //
-    //////////////////////////
+            case token_type::value_integer:
+            {
+                result.m_type = value_t::number_integer;
+                result.m_value = m_lexer.get_number_integer();
+                break;
+            }
 
-    /*!
-    @brief JSON callback events
+            case token_type::value_float:
+            {
+                result.m_type = value_t::number_float;
+                result.m_value = m_lexer.get_number_float();
+
+                // throw in case of infinity or NAN
+                if (JSON_UNLIKELY(not std::isfinite(result.m_value.number_float)))
+                {
+                    if (allow_exceptions)
+                    {
+                        JSON_THROW(out_of_range::create(406, "number overflow parsing '" +
+                                                        m_lexer.get_token_string() + "'"));
+                    }
+                    expect(token_type::uninitialized);
+                }
+                break;
+            }
 
-    This enumeration lists the parser events that can trigger calling a
-    callback function of type @ref parser_callback_t during parsing.
+            case token_type::parse_error:
+            {
+                // using "uninitialized" to avoid "expected" message
+                if (not expect(token_type::uninitialized))
+                {
+                    return;
+                }
+                break; // LCOV_EXCL_LINE
+            }
 
-    @image html callback_events.png "Example when certain parse events are triggered"
+            default:
+            {
+                // the last token was unexpected; we expected a value
+                if (not expect(token_type::literal_or_value))
+                {
+                    return;
+                }
+                break; // LCOV_EXCL_LINE
+            }
+        }
 
-    @since version 1.0.0
+        if (keep and callback and not callback(depth, parse_event_t::value, result))
+        {
+            result.m_type = value_t::discarded;
+        }
+    }
+
+    /*!
+    @brief the actual acceptor
+
+    @invariant 1. The last token is not yet processed. Therefore, the caller
+                  of this function must make sure a token has been read.
+               2. When this function returns, the last token is processed.
+                  That is, the last read character was already considered.
+
+    This invariant makes sure that no token needs to be "unput".
     */
-    enum class parse_event_t : uint8_t
+    bool accept_internal()
     {
-        /// the parser read `{` and started to process a JSON object
-        object_start,
-        /// the parser read `}` and finished processing a JSON object
-        object_end,
-        /// the parser read `[` and started to process a JSON array
-        array_start,
-        /// the parser read `]` and finished processing a JSON array
-        array_end,
-        /// the parser read a key of a value in an object
-        key,
-        /// the parser finished reading a JSON value
-        value
-    };
+        switch (last_token)
+        {
+            case token_type::begin_object:
+            {
+                // read next token
+                get_token();
 
-    /*!
-    @brief per-element parser callback type
+                // closing } -> we are done
+                if (last_token == token_type::end_object)
+                {
+                    return true;
+                }
 
-    With a parser callback function, the result of parsing a JSON text can be
-    influenced. When passed to @ref parse(std::istream&, const
-    parser_callback_t) or @ref parse(const CharT, const parser_callback_t),
-    it is called on certain events (passed as @ref parse_event_t via parameter
-    @a event) with a set recursion depth @a depth and context JSON value
-    @a parsed. The return value of the callback function is a boolean
-    indicating whether the element that emitted the callback shall be kept or
-    not.
+                // parse values
+                while (true)
+                {
+                    // parse key
+                    if (last_token != token_type::value_string)
+                    {
+                        return false;
+                    }
 
-    We distinguish six scenarios (determined by the event type) in which the
-    callback function can be called. The following table describes the values
-    of the parameters @a depth, @a event, and @a parsed.
+                    // parse separator (:)
+                    get_token();
+                    if (last_token != token_type::name_separator)
+                    {
+                        return false;
+                    }
 
-    parameter @a event | description | parameter @a depth | parameter @a parsed
-    ------------------ | ----------- | ------------------ | -------------------
-    parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded
-    parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key
-    parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object
-    parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded
-    parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
-    parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
+                    // parse value
+                    get_token();
+                    if (not accept_internal())
+                    {
+                        return false;
+                    }
 
-    @image html callback_events.png "Example when certain parse events are triggered"
+                    // comma -> next value
+                    get_token();
+                    if (last_token == token_type::value_separator)
+                    {
+                        get_token();
+                        continue;
+                    }
 
-    Discarding a value (i.e., returning `false`) has different effects
-    depending on the context in which function was called:
+                    // closing }
+                    return (last_token == token_type::end_object);
+                }
+            }
 
-    - Discarded values in structured types are skipped. That is, the parser
-      will behave as if the discarded value was never read.
-    - In case a value outside a structured type is skipped, it is replaced
-      with `null`. This case happens if the top-level element is skipped.
+            case token_type::begin_array:
+            {
+                // read next token
+                get_token();
 
-    @param[in] depth  the depth of the recursion during parsing
+                // closing ] -> we are done
+                if (last_token == token_type::end_array)
+                {
+                    return true;
+                }
 
-    @param[in] event  an event of type parse_event_t indicating the context in
-    the callback function has been called
+                // parse values
+                while (true)
+                {
+                    // parse value
+                    if (not accept_internal())
+                    {
+                        return false;
+                    }
 
-    @param[in,out] parsed  the current intermediate parse result; note that
-    writing to this value has no effect for parse_event_t::key events
+                    // comma -> next value
+                    get_token();
+                    if (last_token == token_type::value_separator)
+                    {
+                        get_token();
+                        continue;
+                    }
 
-    @return Whether the JSON value which called the function during parsing
-    should be kept (`true`) or not (`false`). In the latter case, it is either
-    skipped completely or replaced by an empty discarded object.
+                    // closing ]
+                    return (last_token == token_type::end_array);
+                }
+            }
+
+            case token_type::value_float:
+            {
+                // reject infinity or NAN
+                return std::isfinite(m_lexer.get_number_float());
+            }
 
-    @sa @ref parse(std::istream&, parser_callback_t) or
-    @ref parse(const CharT, const parser_callback_t) for examples
+            case token_type::literal_false:
+            case token_type::literal_null:
+            case token_type::literal_true:
+            case token_type::value_integer:
+            case token_type::value_string:
+            case token_type::value_unsigned:
+                return true;
 
-    @since version 1.0.0
+            default: // the last token was unexpected
+                return false;
+        }
+    }
+
+    /// get next token from lexer
+    token_type get_token()
+    {
+        return (last_token = m_lexer.scan());
+    }
+
+    /*!
+    @throw parse_error.101 if expected token did not occur
     */
-    using parser_callback_t = std::function<bool(int depth,
-                              parse_event_t event,
-                              basic_json& parsed)>;
+    bool expect(token_type t)
+    {
+        if (JSON_UNLIKELY(t != last_token))
+        {
+            errored = true;
+            expected = t;
+            if (allow_exceptions)
+            {
+                throw_exception();
+            }
+            else
+            {
+                return false;
+            }
+        }
 
+        return true;
+    }
 
-    //////////////////
-    // constructors //
-    //////////////////
+    [[noreturn]] void throw_exception() const
+    {
+        std::string error_msg = "syntax error - ";
+        if (last_token == token_type::parse_error)
+        {
+            error_msg += std::string(m_lexer.get_error_message()) + "; last read: '" +
+                         m_lexer.get_token_string() + "'";
+        }
+        else
+        {
+            error_msg += "unexpected " + std::string(lexer_t::token_type_name(last_token));
+        }
 
-    /// @name constructors and destructors
-    /// Constructors of class @ref basic_json, copy/move constructor, copy
-    /// assignment, static functions creating objects, and the destructor.
-    /// @{
+        if (expected != token_type::uninitialized)
+        {
+            error_msg += "; expected " + std::string(lexer_t::token_type_name(expected));
+        }
 
-    /*!
-    @brief create an empty value with a given type
+        JSON_THROW(parse_error::create(101, m_lexer.get_position(), error_msg));
+    }
 
-    Create an empty JSON value with a given type. The value will be default
-    initialized with an empty value which depends on the type:
+  private:
+    /// current level of recursion
+    int depth = 0;
+    /// callback function
+    const parser_callback_t callback = nullptr;
+    /// the type of the last read token
+    token_type last_token = token_type::uninitialized;
+    /// the lexer
+    lexer_t m_lexer;
+    /// whether a syntax error occurred
+    bool errored = false;
+    /// possible reason for the syntax error
+    token_type expected = token_type::uninitialized;
+    /// whether to throw exceptions in case of errors
+    const bool allow_exceptions = true;
+};
 
-    Value type  | initial value
-    ----------- | -------------
-    null        | `null`
-    boolean     | `false`
-    string      | `""`
-    number      | `0`
-    object      | `{}`
-    array       | `[]`
+///////////////
+// iterators //
+///////////////
 
-    @param[in] value_type  the type of the value to create
+/*!
+@brief an iterator for primitive JSON types
 
-    @complexity Constant.
+This class models an iterator for primitive JSON types (boolean, number,
+string). It's only purpose is to allow the iterator/const_iterator classes
+to "iterate" over primitive values. Internally, the iterator is modeled by
+a `difference_type` variable. Value begin_value (`0`) models the begin,
+end_value (`1`) models past the end.
+*/
+class primitive_iterator_t
+{
+  public:
+    using difference_type = std::ptrdiff_t;
 
-    @liveexample{The following code shows the constructor for different @ref
-    value_t values,basic_json__value_t}
+    constexpr difference_type get_value() const noexcept
+    {
+        return m_it;
+    }
 
-    @since version 1.0.0
-    */
-    basic_json(const value_t value_type)
-        : m_type(value_type), m_value(value_type)
+    /// set iterator to a defined beginning
+    void set_begin() noexcept
     {
-        assert_invariant();
+        m_it = begin_value;
     }
 
-    /*!
-    @brief create a null object
+    /// set iterator to a defined past the end
+    void set_end() noexcept
+    {
+        m_it = end_value;
+    }
 
-    Create a `null` JSON value. It either takes a null pointer as parameter
-    (explicitly creating `null`) or no parameter (implicitly creating `null`).
-    The passed null pointer itself is not read -- it is only used to choose
-    the right constructor.
+    /// return whether the iterator can be dereferenced
+    constexpr bool is_begin() const noexcept
+    {
+        return m_it == begin_value;
+    }
 
-    @complexity Constant.
+    /// return whether the iterator is at end
+    constexpr bool is_end() const noexcept
+    {
+        return m_it == end_value;
+    }
 
-    @exceptionsafety No-throw guarantee: this constructor never throws
-    exceptions.
+    friend constexpr bool operator==(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it == rhs.m_it;
+    }
 
-    @liveexample{The following code shows the constructor with and without a
-    null pointer parameter.,basic_json__nullptr_t}
+    friend constexpr bool operator<(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it < rhs.m_it;
+    }
 
-    @since version 1.0.0
-    */
-    basic_json(std::nullptr_t = nullptr) noexcept
-        : basic_json(value_t::null)
+    primitive_iterator_t operator+(difference_type i)
     {
-        assert_invariant();
+        auto result = *this;
+        result += i;
+        return result;
     }
 
-    /*!
-    @brief create a JSON value
+    friend constexpr difference_type operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it - rhs.m_it;
+    }
 
-    This is a "catch all" constructor for all compatible JSON types; that is,
-    types for which a `to_json()` method exsits. The constructor forwards the
-    parameter @a val to that method (to `json_serializer<U>::to_json` method
-    with `U = uncvref_t<CompatibleType>`, to be exact).
+    friend std::ostream& operator<<(std::ostream& os, primitive_iterator_t it)
+    {
+        return os << it.m_it;
+    }
 
-    Template type @a CompatibleType includes, but is not limited to, the
-    following types:
-    - **arrays**: @ref array_t and all kinds of compatible containers such as
-      `std::vector`, `std::deque`, `std::list`, `std::forward_list`,
-      `std::array`, `std::set`, `std::unordered_set`, `std::multiset`, and
-      `unordered_multiset` with a `value_type` from which a @ref basic_json
-      value can be constructed.
-    - **objects**: @ref object_t and all kinds of compatible associative
-      containers such as `std::map`, `std::unordered_map`, `std::multimap`,
-      and `std::unordered_multimap` with a `key_type` compatible to
-      @ref string_t and a `value_type` from which a @ref basic_json value can
-      be constructed.
-    - **strings**: @ref string_t, string literals, and all compatible string
-      containers can be used.
-    - **numbers**: @ref number_integer_t, @ref number_unsigned_t,
-      @ref number_float_t, and all convertible number types such as `int`,
-      `size_t`, `int64_t`, `float` or `double` can be used.
-    - **boolean**: @ref boolean_t / `bool` can be used.
-
-    See the examples below.
-
-    @tparam CompatibleType a type such that:
-    - @a CompatibleType is not derived from `std::istream`,
-    - @a CompatibleType is not @ref basic_json (to avoid hijacking copy/move
-         constructors),
-    - @a CompatibleType is not a @ref basic_json nested type (e.g.,
-         @ref json_pointer, @ref iterator, etc ...)
-    - @ref @ref json_serializer<U> has a
-         `to_json(basic_json_t&, CompatibleType&&)` method
-
-    @tparam U = `uncvref_t<CompatibleType>`
+    primitive_iterator_t& operator++()
+    {
+        ++m_it;
+        return *this;
+    }
 
-    @param[in] val the value to be forwarded
+    primitive_iterator_t const operator++(int)
+    {
+        auto result = *this;
+        m_it++;
+        return result;
+    }
 
-    @complexity Usually linear in the size of the passed @a val, also
-                depending on the implementation of the called `to_json()`
-                method.
+    primitive_iterator_t& operator--()
+    {
+        --m_it;
+        return *this;
+    }
 
-    @throw what `json_serializer<U>::to_json()` throws
+    primitive_iterator_t const operator--(int)
+    {
+        auto result = *this;
+        m_it--;
+        return result;
+    }
 
-    @liveexample{The following code shows the constructor with several
-    compatible types.,basic_json__CompatibleType}
+    primitive_iterator_t& operator+=(difference_type n)
+    {
+        m_it += n;
+        return *this;
+    }
 
-    @since version 2.1.0
-    */
-    template<typename CompatibleType, typename U = detail::uncvref_t<CompatibleType>,
-             detail::enable_if_t<not std::is_base_of<std::istream, U>::value and
-                                 not std::is_same<U, basic_json_t>::value and
-                                 not detail::is_basic_json_nested_type<
-                                     basic_json_t, U>::value and
-                                 detail::has_to_json<basic_json, U>::value,
-                                 int> = 0>
-    basic_json(CompatibleType && val) noexcept(noexcept(JSONSerializer<U>::to_json(
-                std::declval<basic_json_t&>(), std::forward<CompatibleType>(val))))
+    primitive_iterator_t& operator-=(difference_type n)
     {
-        JSONSerializer<U>::to_json(*this, std::forward<CompatibleType>(val));
-        assert_invariant();
+        m_it -= n;
+        return *this;
     }
 
-    /*!
-    @brief create a container (array or object) from an initializer list
+  private:
+    static constexpr difference_type begin_value = 0;
+    static constexpr difference_type end_value = begin_value + 1;
 
-    Creates a JSON value of type array or object from the passed initializer
-    list @a init. In case @a type_deduction is `true` (default), the type of
-    the JSON value to be created is deducted from the initializer list @a init
-    according to the following rules:
+    /// iterator as signed integer type
+    difference_type m_it = (std::numeric_limits<std::ptrdiff_t>::min)();
+};
 
-    1. If the list is empty, an empty JSON object value `{}` is created.
-    2. If the list consists of pairs whose first element is a string, a JSON
-       object value is created where the first elements of the pairs are
-       treated as keys and the second elements are as values.
-    3. In all other cases, an array is created.
+/*!
+@brief an iterator value
 
-    The rules aim to create the best fit between a C++ initializer list and
-    JSON values. The rationale is as follows:
+@note This structure could easily be a union, but MSVC currently does not allow
+unions members with complex constructors, see https://github.com/nlohmann/json/pull/105.
+*/
+template<typename BasicJsonType> struct internal_iterator
+{
+    /// iterator for JSON objects
+    typename BasicJsonType::object_t::iterator object_iterator {};
+    /// iterator for JSON arrays
+    typename BasicJsonType::array_t::iterator array_iterator {};
+    /// generic iterator for all other types
+    primitive_iterator_t primitive_iterator {};
+};
 
-    1. The empty initializer list is written as `{}` which is exactly an empty
-       JSON object.
-    2. C++ has now way of describing mapped types other than to list a list of
-       pairs. As JSON requires that keys must be of type string, rule 2 is the
-       weakest constraint one can pose on initializer lists to interpret them
-       as an object.
-    3. In all other cases, the initializer list could not be interpreted as
-       JSON object type, so interpreting it as JSON array type is safe.
+template<typename IteratorType> class iteration_proxy;
 
-    With the rules described above, the following JSON values cannot be
-    expressed by an initializer list:
+/*!
+@brief a template for a bidirectional iterator for the @ref basic_json class
 
-    - the empty array (`[]`): use @ref array(std::initializer_list<basic_json>)
-      with an empty initializer list in this case
-    - arrays whose elements satisfy rule 2: use @ref
-      array(std::initializer_list<basic_json>) with the same initializer list
-      in this case
+This class implements a both iterators (iterator and const_iterator) for the
+@ref basic_json class.
 
-    @note When used without parentheses around an empty initializer list, @ref
-    basic_json() is called instead of this function, yielding the JSON null
-    value.
+@note An iterator is called *initialized* when a pointer to a JSON value has
+      been set (e.g., by a constructor or a copy assignment). If the iterator is
+      default-constructed, it is *uninitialized* and most methods are undefined.
+      **The library uses assertions to detect calls on uninitialized iterators.**
 
-    @param[in] init  initializer list with JSON values
+@requirement The class satisfies the following concept requirements:
+-
+[BidirectionalIterator](http://en.cppreference.com/w/cpp/concept/BidirectionalIterator):
+  The iterator that can be moved can be moved in both directions (i.e.
+  incremented and decremented).
 
-    @param[in] type_deduction internal parameter; when set to `true`, the type
-    of the JSON value is deducted from the initializer list @a init; when set
-    to `false`, the type provided via @a manual_type is forced. This mode is
-    used by the functions @ref array(std::initializer_list<basic_json>) and
-    @ref object(std::initializer_list<basic_json>).
+@since version 1.0.0, simplified in version 2.0.9, change to bidirectional
+       iterators in version 3.0.0 (see https://github.com/nlohmann/json/issues/593)
+*/
+template<typename BasicJsonType>
+class iter_impl
+{
+    /// allow basic_json to access private members
+    friend iter_impl<typename std::conditional<std::is_const<BasicJsonType>::value, typename std::remove_const<BasicJsonType>::type, const BasicJsonType>::type>;
+    friend BasicJsonType;
+    friend iteration_proxy<iter_impl>;
 
-    @param[in] manual_type internal parameter; when @a type_deduction is set
-    to `false`, the created JSON value will use the provided type (only @ref
-    value_t::array and @ref value_t::object are valid); when @a type_deduction
-    is set to `true`, this parameter has no effect
+    using object_t = typename BasicJsonType::object_t;
+    using array_t = typename BasicJsonType::array_t;
+    // make sure BasicJsonType is basic_json or const basic_json
+    static_assert(is_basic_json<typename std::remove_const<BasicJsonType>::type>::value,
+                  "iter_impl only accepts (const) basic_json");
 
-    @throw type_error.301 if @a type_deduction is `false`, @a manual_type is
-    `value_t::object`, but @a init contains an element which is not a pair
-    whose first element is a string. In this case, the constructor could not
-    create an object. If @a type_deduction would have be `true`, an array
-    would have been created. See @ref object(std::initializer_list<basic_json>)
-    for an example.
+  public:
 
-    @complexity Linear in the size of the initializer list @a init.
+    /// The std::iterator class template (used as a base class to provide typedefs) is deprecated in C++17.
+    /// The C++ Standard has never required user-defined iterators to derive from std::iterator.
+    /// A user-defined iterator should provide publicly accessible typedefs named
+    /// iterator_category, value_type, difference_type, pointer, and reference.
+    /// Note that value_type is required to be non-const, even for constant iterators.
+    using iterator_category = std::bidirectional_iterator_tag;
 
-    @liveexample{The example below shows how JSON values are created from
-    initializer lists.,basic_json__list_init_t}
+    /// the type of the values when the iterator is dereferenced
+    using value_type = typename BasicJsonType::value_type;
+    /// a type to represent differences between iterators
+    using difference_type = typename BasicJsonType::difference_type;
+    /// defines a pointer to the type iterated over (value_type)
+    using pointer = typename std::conditional<std::is_const<BasicJsonType>::value,
+          typename BasicJsonType::const_pointer,
+          typename BasicJsonType::pointer>::type;
+    /// defines a reference to the type iterated over (value_type)
+    using reference =
+        typename std::conditional<std::is_const<BasicJsonType>::value,
+        typename BasicJsonType::const_reference,
+        typename BasicJsonType::reference>::type;
 
-    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
-    value from an initializer list
-    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
-    value from an initializer list
+    /// default constructor
+    iter_impl() = default;
 
-    @since version 1.0.0
+    /*!
+    @brief constructor for a given JSON instance
+    @param[in] object  pointer to a JSON object for this iterator
+    @pre object != nullptr
+    @post The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    basic_json(std::initializer_list<basic_json> init,
-               bool type_deduction = true,
-               value_t manual_type = value_t::array)
+    explicit iter_impl(pointer object) noexcept : m_object(object)
     {
-        // check if each element is an array with two elements whose first
-        // element is a string
-        bool is_an_object = std::all_of(init.begin(), init.end(),
-                                        [](const basic_json & element)
-        {
-            return element.is_array() and element.size() == 2 and element[0].is_string();
-        });
+        assert(m_object != nullptr);
 
-        // adjust type if type deduction is not wanted
-        if (not type_deduction)
+        switch (m_object->m_type)
         {
-            // if array is wanted, do not create an object though possible
-            if (manual_type == value_t::array)
+            case value_t::object:
             {
-                is_an_object = false;
+                m_it.object_iterator = typename object_t::iterator();
+                break;
             }
 
-            // if object is wanted but impossible, throw an exception
-            if (manual_type == value_t::object and not is_an_object)
+            case value_t::array:
             {
-                JSON_THROW(type_error::create(301, "cannot create object from initializer list"));
+                m_it.array_iterator = typename array_t::iterator();
+                break;
             }
-        }
-
-        if (is_an_object)
-        {
-            // the initializer list is a list of pairs -> create object
-            m_type = value_t::object;
-            m_value = value_t::object;
 
-            std::for_each(init.begin(), init.end(), [this](const basic_json & element)
+            default:
             {
-                m_value.object->emplace(*(element[0].m_value.string), element[1]);
-            });
-        }
-        else
-        {
-            // the initializer list describes an array -> create array
-            m_type = value_t::array;
-            m_value.array = create<array_t>(init);
+                m_it.primitive_iterator = primitive_iterator_t();
+                break;
+            }
         }
-
-        assert_invariant();
     }
 
     /*!
-    @brief explicitly create an array from an initializer list
-
-    Creates a JSON array value from a given initializer list. That is, given a
-    list of values `a, b, c`, creates the JSON value `[a, b, c]`. If the
-    initializer list is empty, the empty array `[]` is created.
-
-    @note This function is only needed to express two edge cases that cannot
-    be realized with the initializer list constructor (@ref
-    basic_json(std::initializer_list<basic_json>, bool, value_t)). These cases
-    are:
-    1. creating an array whose elements are all pairs whose first element is a
-    string -- in this case, the initializer list constructor would create an
-    object, taking the first elements as keys
-    2. creating an empty array -- passing the empty initializer list to the
-    initializer list constructor yields an empty object
-
-    @param[in] init  initializer list with JSON values to create an array from
-    (optional)
-
-    @return JSON array value
-
-    @complexity Linear in the size of @a init.
-
-    @liveexample{The following code shows an example for the `array`
-    function.,array}
+    @note The conventional copy constructor and copy assignment are implicitly
+          defined. Combined with the following converting constructor and
+          assignment, they support: (1) copy from iterator to iterator, (2)
+          copy from const iterator to const iterator, and (3) conversion from
+          iterator to const iterator. However conversion from const iterator
+          to iterator is not defined.
+    */
 
-    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
-    create a JSON value from an initializer list
-    @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object
-    value from an initializer list
+    /*!
+    @brief converting constructor
+    @param[in] other  non-const iterator to copy from
+    @note It is not checked whether @a other is initialized.
+    */
+    iter_impl(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) noexcept
+        : m_object(other.m_object), m_it(other.m_it) {}
 
-    @since version 1.0.0
+    /*!
+    @brief converting assignment
+    @param[in,out] other  non-const iterator to copy from
+    @return const/non-const iterator
+    @note It is not checked whether @a other is initialized.
     */
-    static basic_json array(std::initializer_list<basic_json> init =
-                                std::initializer_list<basic_json>())
+    iter_impl& operator=(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) noexcept
     {
-        return basic_json(init, false, value_t::array);
+        m_object = other.m_object;
+        m_it = other.m_it;
+        return *this;
     }
 
+  private:
     /*!
-    @brief explicitly create an object from an initializer list
+    @brief set the iterator to the first value
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    void set_begin() noexcept
+    {
+        assert(m_object != nullptr);
 
-    Creates a JSON object value from a given initializer list. The initializer
-    lists elements must be pairs, and their first elements must be strings. If
-    the initializer list is empty, the empty object `{}` is created.
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+            {
+                m_it.object_iterator = m_object->m_value.object->begin();
+                break;
+            }
 
-    @note This function is only added for symmetry reasons. In contrast to the
-    related function @ref array(std::initializer_list<basic_json>), there are
-    no cases which can only be expressed by this function. That is, any
-    initializer list @a init can also be passed to the initializer list
-    constructor @ref basic_json(std::initializer_list<basic_json>, bool, value_t).
+            case value_t::array:
+            {
+                m_it.array_iterator = m_object->m_value.array->begin();
+                break;
+            }
 
-    @param[in] init  initializer list to create an object from (optional)
+            case value_t::null:
+            {
+                // set to end so begin()==end() is true: null is empty
+                m_it.primitive_iterator.set_end();
+                break;
+            }
 
-    @return JSON object value
+            default:
+            {
+                m_it.primitive_iterator.set_begin();
+                break;
+            }
+        }
+    }
 
-    @throw type_error.301 if @a init is not a list of pairs whose first
-    elements are strings. In this case, no object can be created. When such a
-    value is passed to @ref basic_json(std::initializer_list<basic_json>, bool, value_t),
-    an array would have been created from the passed initializer list @a init.
-    See example below.
+    /*!
+    @brief set the iterator past the last value
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    void set_end() noexcept
+    {
+        assert(m_object != nullptr);
 
-    @complexity Linear in the size of @a init.
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+            {
+                m_it.object_iterator = m_object->m_value.object->end();
+                break;
+            }
 
-    @liveexample{The following code shows an example for the `object`
-    function.,object}
+            case value_t::array:
+            {
+                m_it.array_iterator = m_object->m_value.array->end();
+                break;
+            }
 
-    @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) --
-    create a JSON value from an initializer list
-    @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array
-    value from an initializer list
+            default:
+            {
+                m_it.primitive_iterator.set_end();
+                break;
+            }
+        }
+    }
 
-    @since version 1.0.0
+  public:
+    /*!
+    @brief return a reference to the value pointed to by the iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    static basic_json object(std::initializer_list<basic_json> init =
-                                 std::initializer_list<basic_json>())
+    reference operator*() const
     {
-        return basic_json(init, false, value_t::object);
-    }
+        assert(m_object != nullptr);
 
-    /*!
-    @brief construct an array with count copies of given value
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+            {
+                assert(m_it.object_iterator != m_object->m_value.object->end());
+                return m_it.object_iterator->second;
+            }
 
-    Constructs a JSON array value by creating @a cnt copies of a passed value.
-    In case @a cnt is `0`, an empty array is created. As postcondition,
-    `std::distance(begin(),end()) == cnt` holds.
+            case value_t::array:
+            {
+                assert(m_it.array_iterator != m_object->m_value.array->end());
+                return *m_it.array_iterator;
+            }
 
-    @param[in] cnt  the number of JSON copies of @a val to create
-    @param[in] val  the JSON value to copy
+            case value_t::null:
+                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
 
-    @complexity Linear in @a cnt.
-
-    @liveexample{The following code shows examples for the @ref
-    basic_json(size_type\, const basic_json&)
-    constructor.,basic_json__size_type_basic_json}
+            default:
+            {
+                if (JSON_LIKELY(m_it.primitive_iterator.is_begin()))
+                {
+                    return *m_object;
+                }
 
-    @since version 1.0.0
-    */
-    basic_json(size_type cnt, const basic_json& val)
-        : m_type(value_t::array)
-    {
-        m_value.array = create<array_t>(cnt, val);
-        assert_invariant();
+                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
+            }
+        }
     }
 
     /*!
-    @brief construct a JSON container given an iterator range
-
-    Constructs the JSON value with the contents of the range `[first, last)`.
-    The semantics depends on the different types a JSON value can have:
-    - In case of primitive types (number, boolean, or string), @a first must
-      be `begin()` and @a last must be `end()`. In this case, the value is
-      copied. Otherwise, invalid_iterator.204 is thrown.
-    - In case of structured types (array, object), the constructor behaves as
-      similar versions for `std::vector`.
-    - In case of a null type, invalid_iterator.206 is thrown.
-
-    @tparam InputIT an input iterator type (@ref iterator or @ref
-    const_iterator)
-
-    @param[in] first begin of the range to copy from (included)
-    @param[in] last end of the range to copy from (excluded)
-
-    @pre Iterators @a first and @a last must be initialized. **This
-         precondition is enforced with an assertion.**
-
-    @pre Range `[first, last)` is valid. Usually, this precondition cannot be
-         checked efficiently. Only certain edge cases are detected; see the
-         description of the exceptions below.
-
-    @throw invalid_iterator.201 if iterators @a first and @a last are not
-    compatible (i.e., do not belong to the same JSON value). In this case,
-    the range `[first, last)` is undefined.
-    @throw invalid_iterator.204 if iterators @a first and @a last belong to a
-    primitive type (number, boolean, or string), but @a first does not point
-    to the first element any more. In this case, the range `[first, last)` is
-    undefined. See example code below.
-    @throw invalid_iterator.206 if iterators @a first and @a last belong to a
-    null value. In this case, the range `[first, last)` is undefined.
-
-    @complexity Linear in distance between @a first and @a last.
-
-    @liveexample{The example below shows several ways to create JSON values by
-    specifying a subrange with iterators.,basic_json__InputIt_InputIt}
-
-    @since version 1.0.0
+    @brief dereference the iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    template<class InputIT, typename std::enable_if<
-                 std::is_same<InputIT, typename basic_json_t::iterator>::value or
-                 std::is_same<InputIT, typename basic_json_t::const_iterator>::value, int>::type = 0>
-    basic_json(InputIT first, InputIT last)
+    pointer operator->() const
     {
-        assert(first.m_object != nullptr);
-        assert(last.m_object != nullptr);
+        assert(m_object != nullptr);
 
-        // make sure iterator fits the current value
-        if (first.m_object != last.m_object)
+        switch (m_object->m_type)
         {
-            JSON_THROW(invalid_iterator::create(201, "iterators are not compatible"));
-        }
-
-        // copy type from first iterator
-        m_type = first.m_object->m_type;
+            case value_t::object:
+            {
+                assert(m_it.object_iterator != m_object->m_value.object->end());
+                return &(m_it.object_iterator->second);
+            }
 
-        // check if iterator range is complete for primitive values
-        switch (m_type)
-        {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
+            case value_t::array:
             {
-                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
-                {
-                    JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
-                }
-                break;
+                assert(m_it.array_iterator != m_object->m_value.array->end());
+                return &*m_it.array_iterator;
             }
 
             default:
             {
-                break;
+                if (JSON_LIKELY(m_it.primitive_iterator.is_begin()))
+                {
+                    return m_object;
+                }
+
+                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
             }
         }
+    }
 
-        switch (m_type)
+    /*!
+    @brief post-increment (it++)
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl const operator++(int)
+    {
+        auto result = *this;
+        ++(*this);
+        return result;
+    }
+
+    /*!
+    @brief pre-increment (++it)
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl& operator++()
+    {
+        assert(m_object != nullptr);
+
+        switch (m_object->m_type)
         {
-            case value_t::number_integer:
+            case value_t::object:
             {
-                m_value.number_integer = first.m_object->m_value.number_integer;
+                std::advance(m_it.object_iterator, 1);
                 break;
             }
 
-            case value_t::number_unsigned:
+            case value_t::array:
             {
-                m_value.number_unsigned = first.m_object->m_value.number_unsigned;
+                std::advance(m_it.array_iterator, 1);
                 break;
             }
 
-            case value_t::number_float:
+            default:
             {
-                m_value.number_float = first.m_object->m_value.number_float;
+                ++m_it.primitive_iterator;
                 break;
             }
+        }
 
-            case value_t::boolean:
-            {
-                m_value.boolean = first.m_object->m_value.boolean;
-                break;
-            }
+        return *this;
+    }
 
-            case value_t::string:
-            {
-                m_value = *first.m_object->m_value.string;
-                break;
-            }
+    /*!
+    @brief post-decrement (it--)
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl const operator--(int)
+    {
+        auto result = *this;
+        --(*this);
+        return result;
+    }
+
+    /*!
+    @brief pre-decrement (--it)
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl& operator--()
+    {
+        assert(m_object != nullptr);
 
+        switch (m_object->m_type)
+        {
             case value_t::object:
             {
-                m_value.object = create<object_t>(first.m_it.object_iterator,
-                                                  last.m_it.object_iterator);
+                std::advance(m_it.object_iterator, -1);
                 break;
             }
 
             case value_t::array:
             {
-                m_value.array = create<array_t>(first.m_it.array_iterator,
-                                                last.m_it.array_iterator);
+                std::advance(m_it.array_iterator, -1);
                 break;
             }
 
             default:
             {
-                JSON_THROW(invalid_iterator::create(206, "cannot construct with iterators from " +
-                                                    first.m_object->type_name()));
+                --m_it.primitive_iterator;
+                break;
             }
         }
 
-        assert_invariant();
+        return *this;
     }
 
-
-    ///////////////////////////////////////
-    // other constructors and destructor //
-    ///////////////////////////////////////
-
     /*!
-    @brief copy constructor
+    @brief  comparison: equal
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    bool operator==(const iter_impl& other) const
+    {
+        // if objects are not the same, the comparison is undefined
+        if (JSON_UNLIKELY(m_object != other.m_object))
+        {
+            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
+        }
 
-    Creates a copy of a given JSON value.
+        assert(m_object != nullptr);
 
-    @param[in] other  the JSON value to copy
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+                return (m_it.object_iterator == other.m_it.object_iterator);
 
-    @complexity Linear in the size of @a other.
+            case value_t::array:
+                return (m_it.array_iterator == other.m_it.array_iterator);
 
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-    - As postcondition, it holds: `other == basic_json(other)`.
+            default:
+                return (m_it.primitive_iterator == other.m_it.primitive_iterator);
+        }
+    }
 
-    @liveexample{The following code shows an example for the copy
-    constructor.,basic_json__basic_json}
+    /*!
+    @brief  comparison: not equal
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    bool operator!=(const iter_impl& other) const
+    {
+        return not operator==(other);
+    }
 
-    @since version 1.0.0
+    /*!
+    @brief  comparison: smaller
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    basic_json(const basic_json& other)
-        : m_type(other.m_type)
+    bool operator<(const iter_impl& other) const
     {
-        // check of passed value is valid
-        other.assert_invariant();
+        // if objects are not the same, the comparison is undefined
+        if (JSON_UNLIKELY(m_object != other.m_object))
+        {
+            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
+        }
 
-        switch (m_type)
+        assert(m_object != nullptr);
+
+        switch (m_object->m_type)
         {
             case value_t::object:
-            {
-                m_value = *other.m_value.object;
-                break;
-            }
+                JSON_THROW(invalid_iterator::create(213, "cannot compare order of object iterators"));
 
             case value_t::array:
-            {
-                m_value = *other.m_value.array;
-                break;
-            }
+                return (m_it.array_iterator < other.m_it.array_iterator);
 
-            case value_t::string:
-            {
-                m_value = *other.m_value.string;
-                break;
-            }
+            default:
+                return (m_it.primitive_iterator < other.m_it.primitive_iterator);
+        }
+    }
 
-            case value_t::boolean:
-            {
-                m_value = other.m_value.boolean;
-                break;
-            }
+    /*!
+    @brief  comparison: less than or equal
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    bool operator<=(const iter_impl& other) const
+    {
+        return not other.operator < (*this);
+    }
 
-            case value_t::number_integer:
-            {
-                m_value = other.m_value.number_integer;
-                break;
-            }
+    /*!
+    @brief  comparison: greater than
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    bool operator>(const iter_impl& other) const
+    {
+        return not operator<=(other);
+    }
 
-            case value_t::number_unsigned:
-            {
-                m_value = other.m_value.number_unsigned;
-                break;
-            }
+    /*!
+    @brief  comparison: greater than or equal
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    bool operator>=(const iter_impl& other) const
+    {
+        return not operator<(other);
+    }
 
-            case value_t::number_float:
+    /*!
+    @brief  add to iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl& operator+=(difference_type i)
+    {
+        assert(m_object != nullptr);
+
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+                JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));
+
+            case value_t::array:
             {
-                m_value = other.m_value.number_float;
+                std::advance(m_it.array_iterator, i);
                 break;
             }
 
             default:
             {
+                m_it.primitive_iterator += i;
                 break;
             }
         }
 
-        assert_invariant();
+        return *this;
     }
 
     /*!
-    @brief move constructor
+    @brief  subtract from iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl& operator-=(difference_type i)
+    {
+        return operator+=(-i);
+    }
 
-    Move constructor. Constructs a JSON value with the contents of the given
-    value @a other using move semantics. It "steals" the resources from @a
-    other and leaves it as JSON null value.
+    /*!
+    @brief  add to iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl operator+(difference_type i) const
+    {
+        auto result = *this;
+        result += i;
+        return result;
+    }
 
-    @param[in,out] other  value to move to this object
+    /*!
+    @brief  addition of distance and iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    friend iter_impl operator+(difference_type i, const iter_impl& it)
+    {
+        auto result = it;
+        result += i;
+        return result;
+    }
 
-    @post @a other is a JSON null value
-
-    @complexity Constant.
-
-    @liveexample{The code below shows the move constructor explicitly called
-    via std::move.,basic_json__moveconstructor}
-
-    @since version 1.0.0
-    */
-    basic_json(basic_json&& other) noexcept
-        : m_type(std::move(other.m_type)),
-          m_value(std::move(other.m_value))
-    {
-        // check that passed value is valid
-        other.assert_invariant();
-
-        // invalidate payload
-        other.m_type = value_t::null;
-        other.m_value = {};
-
-        assert_invariant();
-    }
+    /*!
+    @brief  subtract from iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl operator-(difference_type i) const
+    {
+        auto result = *this;
+        result -= i;
+        return result;
+    }
 
     /*!
-    @brief copy assignment
-
-    Copy assignment operator. Copies a JSON value via the "copy and swap"
-    strategy: It is expressed in terms of the copy constructor, destructor,
-    and the swap() member function.
-
-    @param[in] other  value to copy from
-
-    @complexity Linear.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-
-    @liveexample{The code below shows and example for the copy assignment. It
-    creates a copy of value `a` which is then swapped with `b`. Finally\, the
-    copy of `a` (which is the null value after the swap) is
-    destroyed.,basic_json__copyassignment}
-
-    @since version 1.0.0
+    @brief  return difference
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    reference& operator=(basic_json other) noexcept (
-        std::is_nothrow_move_constructible<value_t>::value and
-        std::is_nothrow_move_assignable<value_t>::value and
-        std::is_nothrow_move_constructible<json_value>::value and
-        std::is_nothrow_move_assignable<json_value>::value
-    )
+    difference_type operator-(const iter_impl& other) const
     {
-        // check that passed value is valid
-        other.assert_invariant();
+        assert(m_object != nullptr);
 
-        using std::swap;
-        swap(m_type, other.m_type);
-        swap(m_value, other.m_value);
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+                JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));
 
-        assert_invariant();
-        return *this;
+            case value_t::array:
+                return m_it.array_iterator - other.m_it.array_iterator;
+
+            default:
+                return m_it.primitive_iterator - other.m_it.primitive_iterator;
+        }
     }
 
     /*!
-    @brief destructor
-
-    Destroys the JSON value and frees all allocated memory.
-
-    @complexity Linear.
-
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is linear.
-    - All stored elements are destroyed and all memory is freed.
-
-    @since version 1.0.0
+    @brief  access to successor
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    ~basic_json()
+    reference operator[](difference_type n) const
     {
-        assert_invariant();
+        assert(m_object != nullptr);
 
-        switch (m_type)
+        switch (m_object->m_type)
         {
             case value_t::object:
-            {
-                AllocatorType<object_t> alloc;
-                alloc.destroy(m_value.object);
-                alloc.deallocate(m_value.object, 1);
-                break;
-            }
+                JSON_THROW(invalid_iterator::create(208, "cannot use operator[] for object iterators"));
 
             case value_t::array:
-            {
-                AllocatorType<array_t> alloc;
-                alloc.destroy(m_value.array);
-                alloc.deallocate(m_value.array, 1);
-                break;
-            }
+                return *std::next(m_it.array_iterator, n);
 
-            case value_t::string:
-            {
-                AllocatorType<string_t> alloc;
-                alloc.destroy(m_value.string);
-                alloc.deallocate(m_value.string, 1);
-                break;
-            }
+            case value_t::null:
+                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
 
             default:
             {
-                // all other types need no specific destructor
-                break;
+                if (JSON_LIKELY(m_it.primitive_iterator.get_value() == -n))
+                {
+                    return *m_object;
+                }
+
+                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
             }
         }
     }
 
-    /// @}
+    /*!
+    @brief  return the key of an object iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    typename object_t::key_type key() const
+    {
+        assert(m_object != nullptr);
 
-  public:
-    ///////////////////////
-    // object inspection //
-    ///////////////////////
+        if (JSON_LIKELY(m_object->is_object()))
+        {
+            return m_it.object_iterator->first;
+        }
 
-    /// @name object inspection
-    /// Functions to inspect the type of a JSON value.
-    /// @{
+        JSON_THROW(invalid_iterator::create(207, "cannot use key() for non-object iterators"));
+    }
 
     /*!
-    @brief serialization
-
-    Serialization function for JSON values. The function tries to mimic
-    Python's `json.dumps()` function, and currently supports its @a indent
-    parameter.
+    @brief  return the value of an iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    reference value() const
+    {
+        return operator*();
+    }
 
-    @param[in] indent If indent is nonnegative, then array elements and object
-    members will be pretty-printed with that indent level. An indent level of
-    `0` will only insert newlines. `-1` (the default) selects the most compact
-    representation.
+  private:
+    /// associated JSON instance
+    pointer m_object = nullptr;
+    /// the actual iterator of the associated instance
+    internal_iterator<typename std::remove_const<BasicJsonType>::type> m_it = {};
+};
 
-    @return string containing the serialization of the JSON value
+/// proxy class for the iterator_wrapper functions
+template<typename IteratorType> class iteration_proxy
+{
+  private:
+    /// helper class for iteration
+    class iteration_proxy_internal
+    {
+      private:
+        /// the iterator
+        IteratorType anchor;
+        /// an index for arrays (used to create key names)
+        std::size_t array_index = 0;
 
-    @complexity Linear.
+      public:
+        explicit iteration_proxy_internal(IteratorType it) noexcept : anchor(it) {}
 
-    @liveexample{The following example shows the effect of different @a indent
-    parameters to the result of the serialization.,dump}
+        /// dereference operator (needed for range-based for)
+        iteration_proxy_internal& operator*()
+        {
+            return *this;
+        }
 
-    @see https://docs.python.org/2/library/json.html#json.dump
+        /// increment operator (needed for range-based for)
+        iteration_proxy_internal& operator++()
+        {
+            ++anchor;
+            ++array_index;
 
-    @since version 1.0.0
-    */
-    string_t dump(const int indent = -1) const
-    {
-        std::stringstream ss;
-        serializer s(ss);
+            return *this;
+        }
 
-        if (indent >= 0)
+        /// inequality operator (needed for range-based for)
+        bool operator!=(const iteration_proxy_internal& o) const noexcept
         {
-            s.dump(*this, true, static_cast<unsigned int>(indent));
+            return anchor != o.anchor;
         }
-        else
+
+        /// return key of the iterator
+        std::string key() const
         {
-            s.dump(*this, false, 0);
-        }
+            assert(anchor.m_object != nullptr);
 
-        return ss.str();
-    }
+            switch (anchor.m_object->type())
+            {
+                // use integer array index as key
+                case value_t::array:
+                    return std::to_string(array_index);
 
-    /*!
-    @brief return the type of the JSON value (explicit)
+                // use key from the object
+                case value_t::object:
+                    return anchor.key();
 
-    Return the type of the JSON value as a value from the @ref value_t
-    enumeration.
+                // use an empty key for all primitive types
+                default:
+                    return "";
+            }
+        }
 
-    @return the type of the JSON value
+        /// return value of the iterator
+        typename IteratorType::reference value() const
+        {
+            return anchor.value();
+        }
+    };
 
-    @complexity Constant.
+    /// the container to iterate
+    typename IteratorType::reference container;
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+  public:
+    /// construct iteration proxy from a container
+    explicit iteration_proxy(typename IteratorType::reference cont)
+        : container(cont) {}
 
-    @liveexample{The following code exemplifies `type()` for all JSON
-    types.,type}
+    /// return iterator begin (needed for range-based for)
+    iteration_proxy_internal begin() noexcept
+    {
+        return iteration_proxy_internal(container.begin());
+    }
 
-    @since version 1.0.0
-    */
-    constexpr value_t type() const noexcept
+    /// return iterator end (needed for range-based for)
+    iteration_proxy_internal end() noexcept
     {
-        return m_type;
+        return iteration_proxy_internal(container.end());
     }
+};
 
-    /*!
-    @brief return whether type is primitive
+/*!
+@brief a template for a reverse iterator class
 
-    This function returns true iff the JSON type is primitive (string, number,
-    boolean, or null).
+@tparam Base the base iterator type to reverse. Valid types are @ref
+iterator (to create @ref reverse_iterator) and @ref const_iterator (to
+create @ref const_reverse_iterator).
 
-    @return `true` if type is primitive (string, number, boolean, or null),
-    `false` otherwise.
+@requirement The class satisfies the following concept requirements:
+-
+[BidirectionalIterator](http://en.cppreference.com/w/cpp/concept/BidirectionalIterator):
+  The iterator that can be moved can be moved in both directions (i.e.
+  incremented and decremented).
+- [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
+  It is possible to write to the pointed-to element (only if @a Base is
+  @ref iterator).
 
-    @complexity Constant.
+@since version 1.0.0
+*/
+template<typename Base>
+class json_reverse_iterator : public std::reverse_iterator<Base>
+{
+  public:
+    using difference_type = std::ptrdiff_t;
+    /// shortcut to the reverse iterator adapter
+    using base_iterator = std::reverse_iterator<Base>;
+    /// the reference type for the pointed-to element
+    using reference = typename Base::reference;
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+    /// create reverse iterator from iterator
+    json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept
+        : base_iterator(it) {}
 
-    @liveexample{The following code exemplifies `is_primitive()` for all JSON
-    types.,is_primitive}
+    /// create reverse iterator from base class
+    json_reverse_iterator(const base_iterator& it) noexcept : base_iterator(it) {}
 
-    @sa @ref is_structured() -- returns whether JSON value is structured
-    @sa @ref is_null() -- returns whether JSON value is `null`
-    @sa @ref is_string() -- returns whether JSON value is a string
-    @sa @ref is_boolean() -- returns whether JSON value is a boolean
-    @sa @ref is_number() -- returns whether JSON value is a number
+    /// post-increment (it++)
+    json_reverse_iterator const operator++(int)
+    {
+        return static_cast<json_reverse_iterator>(base_iterator::operator++(1));
+    }
 
-    @since version 1.0.0
-    */
-    constexpr bool is_primitive() const noexcept
+    /// pre-increment (++it)
+    json_reverse_iterator& operator++()
     {
-        return is_null() or is_string() or is_boolean() or is_number();
+        return static_cast<json_reverse_iterator&>(base_iterator::operator++());
     }
 
-    /*!
-    @brief return whether type is structured
+    /// post-decrement (it--)
+    json_reverse_iterator const operator--(int)
+    {
+        return static_cast<json_reverse_iterator>(base_iterator::operator--(1));
+    }
 
-    This function returns true iff the JSON type is structured (array or
-    object).
+    /// pre-decrement (--it)
+    json_reverse_iterator& operator--()
+    {
+        return static_cast<json_reverse_iterator&>(base_iterator::operator--());
+    }
 
-    @return `true` if type is structured (array or object), `false` otherwise.
+    /// add to iterator
+    json_reverse_iterator& operator+=(difference_type i)
+    {
+        return static_cast<json_reverse_iterator&>(base_iterator::operator+=(i));
+    }
 
-    @complexity Constant.
+    /// add to iterator
+    json_reverse_iterator operator+(difference_type i) const
+    {
+        return static_cast<json_reverse_iterator>(base_iterator::operator+(i));
+    }
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+    /// subtract from iterator
+    json_reverse_iterator operator-(difference_type i) const
+    {
+        return static_cast<json_reverse_iterator>(base_iterator::operator-(i));
+    }
 
-    @liveexample{The following code exemplifies `is_structured()` for all JSON
-    types.,is_structured}
+    /// return difference
+    difference_type operator-(const json_reverse_iterator& other) const
+    {
+        return base_iterator(*this) - base_iterator(other);
+    }
 
-    @sa @ref is_primitive() -- returns whether value is primitive
-    @sa @ref is_array() -- returns whether value is an array
-    @sa @ref is_object() -- returns whether value is an object
+    /// access to successor
+    reference operator[](difference_type n) const
+    {
+        return *(this->operator+(n));
+    }
 
-    @since version 1.0.0
-    */
-    constexpr bool is_structured() const noexcept
+    /// return the key of an object iterator
+    auto key() const -> decltype(std::declval<Base>().key())
     {
-        return is_array() or is_object();
+        auto it = --this->base();
+        return it.key();
     }
 
-    /*!
-    @brief return whether value is null
+    /// return the value of an iterator
+    reference value() const
+    {
+        auto it = --this->base();
+        return it.operator * ();
+    }
+};
 
-    This function returns true iff the JSON value is null.
+/////////////////////
+// output adapters //
+/////////////////////
 
-    @return `true` if type is null, `false` otherwise.
+/// abstract output adapter interface
+template<typename CharType> struct output_adapter_protocol
+{
+    virtual void write_character(CharType c) = 0;
+    virtual void write_characters(const CharType* s, std::size_t length) = 0;
+    virtual ~output_adapter_protocol() = default;
+};
 
-    @complexity Constant.
+/// a type to simplify interfaces
+template<typename CharType>
+using output_adapter_t = std::shared_ptr<output_adapter_protocol<CharType>>;
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+/// output adapter for byte vectors
+template<typename CharType>
+class output_vector_adapter : public output_adapter_protocol<CharType>
+{
+  public:
+    explicit output_vector_adapter(std::vector<CharType>& vec) : v(vec) {}
 
-    @liveexample{The following code exemplifies `is_null()` for all JSON
-    types.,is_null}
+    void write_character(CharType c) override
+    {
+        v.push_back(c);
+    }
 
-    @since version 1.0.0
-    */
-    constexpr bool is_null() const noexcept
+    void write_characters(const CharType* s, std::size_t length) override
     {
-        return m_type == value_t::null;
+        std::copy(s, s + length, std::back_inserter(v));
     }
 
-    /*!
-    @brief return whether value is a boolean
+  private:
+    std::vector<CharType>& v;
+};
 
-    This function returns true iff the JSON value is a boolean.
+/// output adapter for output streams
+template<typename CharType>
+class output_stream_adapter : public output_adapter_protocol<CharType>
+{
+  public:
+    explicit output_stream_adapter(std::basic_ostream<CharType>& s) : stream(s) {}
 
-    @return `true` if type is boolean, `false` otherwise.
+    void write_character(CharType c) override
+    {
+        stream.put(c);
+    }
 
-    @complexity Constant.
+    void write_characters(const CharType* s, std::size_t length) override
+    {
+        stream.write(s, static_cast<std::streamsize>(length));
+    }
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+  private:
+    std::basic_ostream<CharType>& stream;
+};
 
-    @liveexample{The following code exemplifies `is_boolean()` for all JSON
-    types.,is_boolean}
+/// output adapter for basic_string
+template<typename CharType>
+class output_string_adapter : public output_adapter_protocol<CharType>
+{
+  public:
+    explicit output_string_adapter(std::basic_string<CharType>& s) : str(s) {}
 
-    @since version 1.0.0
-    */
-    constexpr bool is_boolean() const noexcept
+    void write_character(CharType c) override
     {
-        return m_type == value_t::boolean;
+        str.push_back(c);
     }
 
-    /*!
-    @brief return whether value is a number
-
-    This function returns true iff the JSON value is a number. This includes
-    both integer and floating-point values.
-
-    @return `true` if type is number (regardless whether integer, unsigned
-    integer or floating-type), `false` otherwise.
+    void write_characters(const CharType* s, std::size_t length) override
+    {
+        str.append(s, length);
+    }
 
-    @complexity Constant.
+  private:
+    std::basic_string<CharType>& str;
+};
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+template<typename CharType>
+class output_adapter
+{
+  public:
+    output_adapter(std::vector<CharType>& vec)
+        : oa(std::make_shared<output_vector_adapter<CharType>>(vec)) {}
 
-    @liveexample{The following code exemplifies `is_number()` for all JSON
-    types.,is_number}
+    output_adapter(std::basic_ostream<CharType>& s)
+        : oa(std::make_shared<output_stream_adapter<CharType>>(s)) {}
 
-    @sa @ref is_number_integer() -- check if value is an integer or unsigned
-    integer number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
-    @sa @ref is_number_float() -- check if value is a floating-point number
+    output_adapter(std::basic_string<CharType>& s)
+        : oa(std::make_shared<output_string_adapter<CharType>>(s)) {}
 
-    @since version 1.0.0
-    */
-    constexpr bool is_number() const noexcept
+    operator output_adapter_t<CharType>()
     {
-        return is_number_integer() or is_number_float();
+        return oa;
     }
 
-    /*!
-    @brief return whether value is an integer number
-
-    This function returns true iff the JSON value is an integer or unsigned
-    integer number. This excludes floating-point values.
-
-    @return `true` if type is an integer or unsigned integer number, `false`
-    otherwise.
-
-    @complexity Constant.
+  private:
+    output_adapter_t<CharType> oa = nullptr;
+};
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+//////////////////////////////
+// binary reader and writer //
+//////////////////////////////
 
-    @liveexample{The following code exemplifies `is_number_integer()` for all
-    JSON types.,is_number_integer}
+/*!
+@brief deserialization of CBOR and MessagePack values
+*/
+template<typename BasicJsonType>
+class binary_reader
+{
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
 
-    @sa @ref is_number() -- check if value is a number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
-    @sa @ref is_number_float() -- check if value is a floating-point number
+  public:
+    /*!
+    @brief create a binary reader
 
-    @since version 1.0.0
+    @param[in] adapter  input adapter to read from
     */
-    constexpr bool is_number_integer() const noexcept
+    explicit binary_reader(input_adapter_t adapter) : ia(std::move(adapter))
     {
-        return m_type == value_t::number_integer or m_type == value_t::number_unsigned;
+        assert(ia);
     }
 
     /*!
-    @brief return whether value is an unsigned integer number
-
-    This function returns true iff the JSON value is an unsigned integer
-    number. This excludes floating-point and (signed) integer values.
-
-    @return `true` if type is an unsigned integer number, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number_unsigned()` for all
-    JSON types.,is_number_unsigned}
+    @brief create a JSON value from CBOR input
 
-    @sa @ref is_number() -- check if value is a number
-    @sa @ref is_number_integer() -- check if value is an integer or unsigned
-    integer number
-    @sa @ref is_number_float() -- check if value is a floating-point number
+    @param[in] strict  whether to expect the input to be consumed completed
+    @return JSON value created from CBOR input
 
-    @since version 2.0.0
+    @throw parse_error.110 if input ended unexpectedly or the end of file was
+                           not reached when @a strict was set to true
+    @throw parse_error.112 if unsupported byte was read
     */
-    constexpr bool is_number_unsigned() const noexcept
+    BasicJsonType parse_cbor(const bool strict)
     {
-        return m_type == value_t::number_unsigned;
+        const auto res = parse_cbor_internal();
+        if (strict)
+        {
+            get();
+            check_eof(true);
+        }
+        return res;
     }
 
     /*!
-    @brief return whether value is a floating-point number
-
-    This function returns true iff the JSON value is a floating-point number.
-    This excludes integer and unsigned integer values.
-
-    @return `true` if type is a floating-point number, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
-
-    @liveexample{The following code exemplifies `is_number_float()` for all
-    JSON types.,is_number_float}
+    @brief create a JSON value from MessagePack input
 
-    @sa @ref is_number() -- check if value is number
-    @sa @ref is_number_integer() -- check if value is an integer number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
-    number
+    @param[in] strict  whether to expect the input to be consumed completed
+    @return JSON value created from MessagePack input
 
-    @since version 1.0.0
+    @throw parse_error.110 if input ended unexpectedly or the end of file was
+                           not reached when @a strict was set to true
+    @throw parse_error.112 if unsupported byte was read
     */
-    constexpr bool is_number_float() const noexcept
+    BasicJsonType parse_msgpack(const bool strict)
     {
-        return m_type == value_t::number_float;
+        const auto res = parse_msgpack_internal();
+        if (strict)
+        {
+            get();
+            check_eof(true);
+        }
+        return res;
     }
 
     /*!
-    @brief return whether value is an object
-
-    This function returns true iff the JSON value is an object.
-
-    @return `true` if type is object, `false` otherwise.
-
-    @complexity Constant.
-
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+    @brief determine system byte order
 
-    @liveexample{The following code exemplifies `is_object()` for all JSON
-    types.,is_object}
+    @return true if and only if system's byte order is little endian
 
-    @since version 1.0.0
+    @note from http://stackoverflow.com/a/1001328/266378
     */
-    constexpr bool is_object() const noexcept
+    static constexpr bool little_endianess(int num = 1) noexcept
     {
-        return m_type == value_t::object;
+        return (*reinterpret_cast<char*>(&num) == 1);
     }
 
+  private:
     /*!
-    @brief return whether value is an array
-
-    This function returns true iff the JSON value is an array.
+    @param[in] get_char  whether a new character should be retrieved from the
+                         input (true, default) or whether the last read
+                         character should be considered instead
+    */
+    BasicJsonType parse_cbor_internal(const bool get_char = true)
+    {
+        switch (get_char ? get() : current)
+        {
+            // EOF
+            case std::char_traits<char>::eof():
+                JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));
 
-    @return `true` if type is array, `false` otherwise.
+            // Integer 0x00..0x17 (0..23)
+            case 0x00:
+            case 0x01:
+            case 0x02:
+            case 0x03:
+            case 0x04:
+            case 0x05:
+            case 0x06:
+            case 0x07:
+            case 0x08:
+            case 0x09:
+            case 0x0A:
+            case 0x0B:
+            case 0x0C:
+            case 0x0D:
+            case 0x0E:
+            case 0x0F:
+            case 0x10:
+            case 0x11:
+            case 0x12:
+            case 0x13:
+            case 0x14:
+            case 0x15:
+            case 0x16:
+            case 0x17:
+                return static_cast<number_unsigned_t>(current);
 
-    @complexity Constant.
+            case 0x18: // Unsigned integer (one-byte uint8_t follows)
+                return get_number<uint8_t>();
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+            case 0x19: // Unsigned integer (two-byte uint16_t follows)
+                return get_number<uint16_t>();
 
-    @liveexample{The following code exemplifies `is_array()` for all JSON
-    types.,is_array}
+            case 0x1A: // Unsigned integer (four-byte uint32_t follows)
+                return get_number<uint32_t>();
 
-    @since version 1.0.0
-    */
-    constexpr bool is_array() const noexcept
-    {
-        return m_type == value_t::array;
-    }
+            case 0x1B: // Unsigned integer (eight-byte uint64_t follows)
+                return get_number<uint64_t>();
 
-    /*!
-    @brief return whether value is a string
+            // Negative integer -1-0x00..-1-0x17 (-1..-24)
+            case 0x20:
+            case 0x21:
+            case 0x22:
+            case 0x23:
+            case 0x24:
+            case 0x25:
+            case 0x26:
+            case 0x27:
+            case 0x28:
+            case 0x29:
+            case 0x2A:
+            case 0x2B:
+            case 0x2C:
+            case 0x2D:
+            case 0x2E:
+            case 0x2F:
+            case 0x30:
+            case 0x31:
+            case 0x32:
+            case 0x33:
+            case 0x34:
+            case 0x35:
+            case 0x36:
+            case 0x37:
+                return static_cast<int8_t>(0x20 - 1 - current);
 
-    This function returns true iff the JSON value is a string.
+            case 0x38: // Negative integer (one-byte uint8_t follows)
+            {
+                // must be uint8_t !
+                return static_cast<number_integer_t>(-1) - get_number<uint8_t>();
+            }
 
-    @return `true` if type is string, `false` otherwise.
+            case 0x39: // Negative integer -1-n (two-byte uint16_t follows)
+            {
+                return static_cast<number_integer_t>(-1) - get_number<uint16_t>();
+            }
 
-    @complexity Constant.
+            case 0x3A: // Negative integer -1-n (four-byte uint32_t follows)
+            {
+                return static_cast<number_integer_t>(-1) - get_number<uint32_t>();
+            }
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+            case 0x3B: // Negative integer -1-n (eight-byte uint64_t follows)
+            {
+                return static_cast<number_integer_t>(-1) -
+                       static_cast<number_integer_t>(get_number<uint64_t>());
+            }
 
-    @liveexample{The following code exemplifies `is_string()` for all JSON
-    types.,is_string}
+            // UTF-8 string (0x00..0x17 bytes follow)
+            case 0x60:
+            case 0x61:
+            case 0x62:
+            case 0x63:
+            case 0x64:
+            case 0x65:
+            case 0x66:
+            case 0x67:
+            case 0x68:
+            case 0x69:
+            case 0x6A:
+            case 0x6B:
+            case 0x6C:
+            case 0x6D:
+            case 0x6E:
+            case 0x6F:
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77:
+            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
+            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
+            case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
+            case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
+            case 0x7F: // UTF-8 string (indefinite length)
+            {
+                return get_cbor_string();
+            }
 
-    @since version 1.0.0
-    */
-    constexpr bool is_string() const noexcept
-    {
-        return m_type == value_t::string;
-    }
+            // array (0x00..0x17 data items follow)
+            case 0x80:
+            case 0x81:
+            case 0x82:
+            case 0x83:
+            case 0x84:
+            case 0x85:
+            case 0x86:
+            case 0x87:
+            case 0x88:
+            case 0x89:
+            case 0x8A:
+            case 0x8B:
+            case 0x8C:
+            case 0x8D:
+            case 0x8E:
+            case 0x8F:
+            case 0x90:
+            case 0x91:
+            case 0x92:
+            case 0x93:
+            case 0x94:
+            case 0x95:
+            case 0x96:
+            case 0x97:
+            {
+                return get_cbor_array(current & 0x1F);
+            }
 
-    /*!
-    @brief return whether value is discarded
+            case 0x98: // array (one-byte uint8_t for n follows)
+            {
+                return get_cbor_array(get_number<uint8_t>());
+            }
 
-    This function returns true iff the JSON value was discarded during parsing
-    with a callback function (see @ref parser_callback_t).
+            case 0x99: // array (two-byte uint16_t for n follow)
+            {
+                return get_cbor_array(get_number<uint16_t>());
+            }
 
-    @note This function will always be `false` for JSON values after parsing.
-    That is, discarded values can only occur during parsing, but will be
-    removed when inside a structured value or replaced by null in other cases.
+            case 0x9A: // array (four-byte uint32_t for n follow)
+            {
+                return get_cbor_array(get_number<uint32_t>());
+            }
 
-    @return `true` if type is discarded, `false` otherwise.
+            case 0x9B: // array (eight-byte uint64_t for n follow)
+            {
+                return get_cbor_array(get_number<uint64_t>());
+            }
 
-    @complexity Constant.
+            case 0x9F: // array (indefinite length)
+            {
+                BasicJsonType result = value_t::array;
+                while (get() != 0xFF)
+                {
+                    result.push_back(parse_cbor_internal(false));
+                }
+                return result;
+            }
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+            // map (0x00..0x17 pairs of data items follow)
+            case 0xA0:
+            case 0xA1:
+            case 0xA2:
+            case 0xA3:
+            case 0xA4:
+            case 0xA5:
+            case 0xA6:
+            case 0xA7:
+            case 0xA8:
+            case 0xA9:
+            case 0xAA:
+            case 0xAB:
+            case 0xAC:
+            case 0xAD:
+            case 0xAE:
+            case 0xAF:
+            case 0xB0:
+            case 0xB1:
+            case 0xB2:
+            case 0xB3:
+            case 0xB4:
+            case 0xB5:
+            case 0xB6:
+            case 0xB7:
+            {
+                return get_cbor_object(current & 0x1F);
+            }
 
-    @liveexample{The following code exemplifies `is_discarded()` for all JSON
-    types.,is_discarded}
+            case 0xB8: // map (one-byte uint8_t for n follows)
+            {
+                return get_cbor_object(get_number<uint8_t>());
+            }
 
-    @since version 1.0.0
-    */
-    constexpr bool is_discarded() const noexcept
-    {
-        return m_type == value_t::discarded;
-    }
+            case 0xB9: // map (two-byte uint16_t for n follow)
+            {
+                return get_cbor_object(get_number<uint16_t>());
+            }
 
-    /*!
-    @brief return the type of the JSON value (implicit)
+            case 0xBA: // map (four-byte uint32_t for n follow)
+            {
+                return get_cbor_object(get_number<uint32_t>());
+            }
 
-    Implicitly return the type of the JSON value as a value from the @ref
-    value_t enumeration.
+            case 0xBB: // map (eight-byte uint64_t for n follow)
+            {
+                return get_cbor_object(get_number<uint64_t>());
+            }
 
-    @return the type of the JSON value
+            case 0xBF: // map (indefinite length)
+            {
+                BasicJsonType result = value_t::object;
+                while (get() != 0xFF)
+                {
+                    auto key = get_cbor_string();
+                    result[key] = parse_cbor_internal();
+                }
+                return result;
+            }
 
-    @complexity Constant.
+            case 0xF4: // false
+            {
+                return false;
+            }
 
-    @exceptionsafety No-throw guarantee: this member function never throws
-    exceptions.
+            case 0xF5: // true
+            {
+                return true;
+            }
 
-    @liveexample{The following code exemplifies the @ref value_t operator for
-    all JSON types.,operator__value_t}
+            case 0xF6: // null
+            {
+                return value_t::null;
+            }
 
-    @since version 1.0.0
-    */
-    constexpr operator value_t() const noexcept
-    {
-        return m_type;
-    }
+            case 0xF9: // Half-Precision Float (two-byte IEEE 754)
+            {
+                const int byte1 = get();
+                check_eof();
+                const int byte2 = get();
+                check_eof();
 
-    /// @}
+                // code from RFC 7049, Appendix D, Figure 3:
+                // As half-precision floating-point numbers were only added
+                // to IEEE 754 in 2008, today's programming platforms often
+                // still only have limited support for them. It is very
+                // easy to include at least decoding support for them even
+                // without such support. An example of a small decoder for
+                // half-precision floating-point numbers in the C language
+                // is shown in Fig. 3.
+                const int half = (byte1 << 8) + byte2;
+                const int exp = (half >> 10) & 0x1F;
+                const int mant = half & 0x3FF;
+                double val;
+                if (exp == 0)
+                {
+                    val = std::ldexp(mant, -24);
+                }
+                else if (exp != 31)
+                {
+                    val = std::ldexp(mant + 1024, exp - 25);
+                }
+                else
+                {
+                    val = (mant == 0) ? std::numeric_limits<double>::infinity()
+                          : std::numeric_limits<double>::quiet_NaN();
+                }
+                return (half & 0x8000) != 0 ? -val : val;
+            }
 
-  private:
-    //////////////////
-    // value access //
-    //////////////////
+            case 0xFA: // Single-Precision Float (four-byte IEEE 754)
+            {
+                return get_number<float>();
+            }
 
-    /// get a boolean (explicit)
-    boolean_t get_impl(boolean_t* /*unused*/) const
-    {
-        if (is_boolean())
-        {
-            return m_value.boolean;
-        }
+            case 0xFB: // Double-Precision Float (eight-byte IEEE 754)
+            {
+                return get_number<double>();
+            }
 
-        JSON_THROW(type_error::create(302, "type must be boolean, but is " + type_name()));
+            default: // anything else (0xFF is handled inside the other types)
+            {
+                std::stringstream ss;
+                ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
+                JSON_THROW(parse_error::create(112, chars_read, "error reading CBOR; last byte: 0x" + ss.str()));
+            }
+        }
     }
 
-    /// get a pointer to the value (object)
-    object_t* get_impl_ptr(object_t* /*unused*/) noexcept
+    BasicJsonType parse_msgpack_internal()
     {
-        return is_object() ? m_value.object : nullptr;
-    }
+        switch (get())
+        {
+            // EOF
+            case std::char_traits<char>::eof():
+                JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));
 
-    /// get a pointer to the value (object)
-    constexpr const object_t* get_impl_ptr(const object_t* /*unused*/) const noexcept
-    {
-        return is_object() ? m_value.object : nullptr;
-    }
+            // positive fixint
+            case 0x00:
+            case 0x01:
+            case 0x02:
+            case 0x03:
+            case 0x04:
+            case 0x05:
+            case 0x06:
+            case 0x07:
+            case 0x08:
+            case 0x09:
+            case 0x0A:
+            case 0x0B:
+            case 0x0C:
+            case 0x0D:
+            case 0x0E:
+            case 0x0F:
+            case 0x10:
+            case 0x11:
+            case 0x12:
+            case 0x13:
+            case 0x14:
+            case 0x15:
+            case 0x16:
+            case 0x17:
+            case 0x18:
+            case 0x19:
+            case 0x1A:
+            case 0x1B:
+            case 0x1C:
+            case 0x1D:
+            case 0x1E:
+            case 0x1F:
+            case 0x20:
+            case 0x21:
+            case 0x22:
+            case 0x23:
+            case 0x24:
+            case 0x25:
+            case 0x26:
+            case 0x27:
+            case 0x28:
+            case 0x29:
+            case 0x2A:
+            case 0x2B:
+            case 0x2C:
+            case 0x2D:
+            case 0x2E:
+            case 0x2F:
+            case 0x30:
+            case 0x31:
+            case 0x32:
+            case 0x33:
+            case 0x34:
+            case 0x35:
+            case 0x36:
+            case 0x37:
+            case 0x38:
+            case 0x39:
+            case 0x3A:
+            case 0x3B:
+            case 0x3C:
+            case 0x3D:
+            case 0x3E:
+            case 0x3F:
+            case 0x40:
+            case 0x41:
+            case 0x42:
+            case 0x43:
+            case 0x44:
+            case 0x45:
+            case 0x46:
+            case 0x47:
+            case 0x48:
+            case 0x49:
+            case 0x4A:
+            case 0x4B:
+            case 0x4C:
+            case 0x4D:
+            case 0x4E:
+            case 0x4F:
+            case 0x50:
+            case 0x51:
+            case 0x52:
+            case 0x53:
+            case 0x54:
+            case 0x55:
+            case 0x56:
+            case 0x57:
+            case 0x58:
+            case 0x59:
+            case 0x5A:
+            case 0x5B:
+            case 0x5C:
+            case 0x5D:
+            case 0x5E:
+            case 0x5F:
+            case 0x60:
+            case 0x61:
+            case 0x62:
+            case 0x63:
+            case 0x64:
+            case 0x65:
+            case 0x66:
+            case 0x67:
+            case 0x68:
+            case 0x69:
+            case 0x6A:
+            case 0x6B:
+            case 0x6C:
+            case 0x6D:
+            case 0x6E:
+            case 0x6F:
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77:
+            case 0x78:
+            case 0x79:
+            case 0x7A:
+            case 0x7B:
+            case 0x7C:
+            case 0x7D:
+            case 0x7E:
+            case 0x7F:
+                return static_cast<number_unsigned_t>(current);
+
+            // fixmap
+            case 0x80:
+            case 0x81:
+            case 0x82:
+            case 0x83:
+            case 0x84:
+            case 0x85:
+            case 0x86:
+            case 0x87:
+            case 0x88:
+            case 0x89:
+            case 0x8A:
+            case 0x8B:
+            case 0x8C:
+            case 0x8D:
+            case 0x8E:
+            case 0x8F:
+            {
+                return get_msgpack_object(current & 0x0F);
+            }
 
-    /// get a pointer to the value (array)
-    array_t* get_impl_ptr(array_t* /*unused*/) noexcept
-    {
-        return is_array() ? m_value.array : nullptr;
-    }
+            // fixarray
+            case 0x90:
+            case 0x91:
+            case 0x92:
+            case 0x93:
+            case 0x94:
+            case 0x95:
+            case 0x96:
+            case 0x97:
+            case 0x98:
+            case 0x99:
+            case 0x9A:
+            case 0x9B:
+            case 0x9C:
+            case 0x9D:
+            case 0x9E:
+            case 0x9F:
+            {
+                return get_msgpack_array(current & 0x0F);
+            }
+
+            // fixstr
+            case 0xA0:
+            case 0xA1:
+            case 0xA2:
+            case 0xA3:
+            case 0xA4:
+            case 0xA5:
+            case 0xA6:
+            case 0xA7:
+            case 0xA8:
+            case 0xA9:
+            case 0xAA:
+            case 0xAB:
+            case 0xAC:
+            case 0xAD:
+            case 0xAE:
+            case 0xAF:
+            case 0xB0:
+            case 0xB1:
+            case 0xB2:
+            case 0xB3:
+            case 0xB4:
+            case 0xB5:
+            case 0xB6:
+            case 0xB7:
+            case 0xB8:
+            case 0xB9:
+            case 0xBA:
+            case 0xBB:
+            case 0xBC:
+            case 0xBD:
+            case 0xBE:
+            case 0xBF:
+                return get_msgpack_string();
+
+            case 0xC0: // nil
+                return value_t::null;
 
-    /// get a pointer to the value (array)
-    constexpr const array_t* get_impl_ptr(const array_t* /*unused*/) const noexcept
-    {
-        return is_array() ? m_value.array : nullptr;
-    }
+            case 0xC2: // false
+                return false;
 
-    /// get a pointer to the value (string)
-    string_t* get_impl_ptr(string_t* /*unused*/) noexcept
-    {
-        return is_string() ? m_value.string : nullptr;
-    }
+            case 0xC3: // true
+                return true;
 
-    /// get a pointer to the value (string)
-    constexpr const string_t* get_impl_ptr(const string_t* /*unused*/) const noexcept
-    {
-        return is_string() ? m_value.string : nullptr;
-    }
+            case 0xCA: // float 32
+                return get_number<float>();
 
-    /// get a pointer to the value (boolean)
-    boolean_t* get_impl_ptr(boolean_t* /*unused*/) noexcept
-    {
-        return is_boolean() ? &m_value.boolean : nullptr;
-    }
+            case 0xCB: // float 64
+                return get_number<double>();
 
-    /// get a pointer to the value (boolean)
-    constexpr const boolean_t* get_impl_ptr(const boolean_t* /*unused*/) const noexcept
-    {
-        return is_boolean() ? &m_value.boolean : nullptr;
-    }
+            case 0xCC: // uint 8
+                return get_number<uint8_t>();
 
-    /// get a pointer to the value (integer number)
-    number_integer_t* get_impl_ptr(number_integer_t* /*unused*/) noexcept
-    {
-        return is_number_integer() ? &m_value.number_integer : nullptr;
-    }
+            case 0xCD: // uint 16
+                return get_number<uint16_t>();
 
-    /// get a pointer to the value (integer number)
-    constexpr const number_integer_t* get_impl_ptr(const number_integer_t* /*unused*/) const noexcept
-    {
-        return is_number_integer() ? &m_value.number_integer : nullptr;
-    }
+            case 0xCE: // uint 32
+                return get_number<uint32_t>();
 
-    /// get a pointer to the value (unsigned number)
-    number_unsigned_t* get_impl_ptr(number_unsigned_t* /*unused*/) noexcept
-    {
-        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
-    }
+            case 0xCF: // uint 64
+                return get_number<uint64_t>();
 
-    /// get a pointer to the value (unsigned number)
-    constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t* /*unused*/) const noexcept
-    {
-        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
-    }
+            case 0xD0: // int 8
+                return get_number<int8_t>();
 
-    /// get a pointer to the value (floating-point number)
-    number_float_t* get_impl_ptr(number_float_t* /*unused*/) noexcept
-    {
-        return is_number_float() ? &m_value.number_float : nullptr;
-    }
+            case 0xD1: // int 16
+                return get_number<int16_t>();
 
-    /// get a pointer to the value (floating-point number)
-    constexpr const number_float_t* get_impl_ptr(const number_float_t* /*unused*/) const noexcept
-    {
-        return is_number_float() ? &m_value.number_float : nullptr;
-    }
+            case 0xD2: // int 32
+                return get_number<int32_t>();
 
-    /*!
-    @brief helper function to implement get_ref()
+            case 0xD3: // int 64
+                return get_number<int64_t>();
 
-    This funcion helps to implement get_ref() without code duplication for
-    const and non-const overloads
+            case 0xD9: // str 8
+            case 0xDA: // str 16
+            case 0xDB: // str 32
+                return get_msgpack_string();
 
-    @tparam ThisType will be deduced as `basic_json` or `const basic_json`
+            case 0xDC: // array 16
+            {
+                return get_msgpack_array(get_number<uint16_t>());
+            }
 
-    @throw type_error.303 if ReferenceType does not match underlying value
-    type of the current JSON
-    */
-    template<typename ReferenceType, typename ThisType>
-    static ReferenceType get_ref_impl(ThisType& obj)
-    {
-        // helper type
-        using PointerType = typename std::add_pointer<ReferenceType>::type;
+            case 0xDD: // array 32
+            {
+                return get_msgpack_array(get_number<uint32_t>());
+            }
 
-        // delegate the call to get_ptr<>()
-        auto ptr = obj.template get_ptr<PointerType>();
+            case 0xDE: // map 16
+            {
+                return get_msgpack_object(get_number<uint16_t>());
+            }
 
-        if (ptr != nullptr)
-        {
-            return *ptr;
-        }
+            case 0xDF: // map 32
+            {
+                return get_msgpack_object(get_number<uint32_t>());
+            }
 
-        JSON_THROW(type_error::create(303, "incompatible ReferenceType for get_ref, actual type is " + obj.type_name()));
-    }
+            // positive fixint
+            case 0xE0:
+            case 0xE1:
+            case 0xE2:
+            case 0xE3:
+            case 0xE4:
+            case 0xE5:
+            case 0xE6:
+            case 0xE7:
+            case 0xE8:
+            case 0xE9:
+            case 0xEA:
+            case 0xEB:
+            case 0xEC:
+            case 0xED:
+            case 0xEE:
+            case 0xEF:
+            case 0xF0:
+            case 0xF1:
+            case 0xF2:
+            case 0xF3:
+            case 0xF4:
+            case 0xF5:
+            case 0xF6:
+            case 0xF7:
+            case 0xF8:
+            case 0xF9:
+            case 0xFA:
+            case 0xFB:
+            case 0xFC:
+            case 0xFD:
+            case 0xFE:
+            case 0xFF:
+                return static_cast<int8_t>(current);
 
-  public:
-    /// @name value access
-    /// Direct access to the stored value of a JSON value.
-    /// @{
+            default: // anything else
+            {
+                std::stringstream ss;
+                ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
+                JSON_THROW(parse_error::create(112, chars_read,
+                                               "error reading MessagePack; last byte: 0x" + ss.str()));
+            }
+        }
+    }
 
     /*!
-    @brief get special-case overload
+    @brief get next character from the input
 
-    This overloads avoids a lot of template boilerplate, it can be seen as the
-    identity method
+    This function provides the interface to the used input adapter. It does
+    not throw in case the input reached EOF, but returns a -'ve valued
+    `std::char_traits<char>::eof()` in that case.
 
-    @tparam BasicJsonType == @ref basic_json
+    @return character read from the input
+    */
+    int get()
+    {
+        ++chars_read;
+        return (current = ia->get_character());
+    }
 
-    @return a copy of *this
+    /*
+    @brief read a number from the input
 
-    @complexity Constant.
+    @tparam NumberType the type of the number
 
-    @since version 2.1.0
+    @return number of type @a NumberType
+
+    @note This function needs to respect the system's endianess, because
+          bytes in CBOR and MessagePack are stored in network order (big
+          endian) and therefore need reordering on little endian systems.
+
+    @throw parse_error.110 if input has less than `sizeof(NumberType)` bytes
     */
-    template <
-        typename BasicJsonType,
-        detail::enable_if_t<std::is_same<typename std::remove_const<BasicJsonType>::type,
-                                         basic_json_t>::value,
-                            int> = 0 >
-    basic_json get() const
+    template<typename NumberType> NumberType get_number()
     {
-        return *this;
+        // step 1: read input into array with system's byte order
+        std::array<uint8_t, sizeof(NumberType)> vec;
+        for (std::size_t i = 0; i < sizeof(NumberType); ++i)
+        {
+            get();
+            check_eof();
+
+            // reverse byte order prior to conversion if necessary
+            if (is_little_endian)
+            {
+                vec[sizeof(NumberType) - i - 1] = static_cast<uint8_t>(current);
+            }
+            else
+            {
+                vec[i] = static_cast<uint8_t>(current); // LCOV_EXCL_LINE
+            }
+        }
+
+        // step 2: convert array into number of type T and return
+        NumberType result;
+        std::memcpy(&result, vec.data(), sizeof(NumberType));
+        return result;
     }
 
     /*!
-    @brief get a value (explicit)
+    @brief create a string by reading characters from the input
 
-    Explicit type conversion between the JSON value and a compatible value
-    which is [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible)
-    and [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible).
-    The value is converted by calling the @ref json_serializer<ValueType>
-    `from_json()` method.
+    @param[in] len number of bytes to read
 
-    The function is equivalent to executing
-    @code {.cpp}
-    ValueType ret;
-    JSONSerializer<ValueType>::from_json(*this, ret);
-    return ret;
-    @endcode
+    @note We can not reserve @a len bytes for the result, because @a len
+          may be too large. Usually, @ref check_eof() detects the end of
+          the input before we run out of string memory.
 
-    This overloads is chosen if:
-    - @a ValueType is not @ref basic_json,
-    - @ref json_serializer<ValueType> has a `from_json()` method of the form
-      `void from_json(const @ref basic_json&, ValueType&)`, and
-    - @ref json_serializer<ValueType> does not have a `from_json()` method of
-      the form `ValueType from_json(const @ref basic_json&)`
+    @return string created by reading @a len bytes
 
-    @tparam ValueTypeCV the provided value type
-    @tparam ValueType the returned value type
+    @throw parse_error.110 if input has less than @a len bytes
+    */
+    template<typename NumberType>
+    std::string get_string(const NumberType len)
+    {
+        std::string result;
+        std::generate_n(std::back_inserter(result), len, [this]()
+        {
+            get();
+            check_eof();
+            return static_cast<char>(current);
+        });
+        return result;
+    }
 
-    @return copy of the JSON value, converted to @a ValueType
+    /*!
+    @brief reads a CBOR string
 
-    @throw what @ref json_serializer<ValueType> `from_json()` method throws
+    This function first reads starting bytes to determine the expected
+    string length and then copies this number of bytes into a string.
+    Additionally, CBOR's strings with indefinite lengths are supported.
 
-    @liveexample{The example below shows several conversions from JSON values
-    to other types. There a few things to note: (1) Floating-point numbers can
-    be converted to integers\, (2) A JSON array can be converted to a standard
-    `std::vector<short>`\, (3) A JSON object can be converted to C++
-    associative containers such as `std::unordered_map<std::string\,
-    json>`.,get__ValueType_const}
+    @return string
 
-    @since version 2.1.0
+    @throw parse_error.110 if input ended
+    @throw parse_error.113 if an unexpected byte is read
     */
-    template <
-        typename ValueTypeCV,
-        typename ValueType = detail::uncvref_t<ValueTypeCV>,
-        detail::enable_if_t <
-            not std::is_same<basic_json_t, ValueType>::value and
-            detail::has_from_json<basic_json_t, ValueType>::value and
-            not detail::has_non_default_from_json<basic_json_t, ValueType>::value,
-            int > = 0 >
-    ValueType get() const noexcept(noexcept(
-                                       JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), std::declval<ValueType&>())))
+    std::string get_cbor_string()
     {
-        // we cannot static_assert on ValueTypeCV being non-const, because
-        // there is support for get<const basic_json_t>(), which is why we
-        // still need the uncvref
-        static_assert(not std::is_reference<ValueTypeCV>::value,
-                      "get() cannot be used with reference types, you might want to use get_ref()");
-        static_assert(std::is_default_constructible<ValueType>::value,
-                      "types must be DefaultConstructible when used with get()");
-
-        ValueType ret;
-        JSONSerializer<ValueType>::from_json(*this, ret);
-        return ret;
-    }
+        check_eof();
 
-    /*!
-    @brief get a value (explicit); special case
+        switch (current)
+        {
+            // UTF-8 string (0x00..0x17 bytes follow)
+            case 0x60:
+            case 0x61:
+            case 0x62:
+            case 0x63:
+            case 0x64:
+            case 0x65:
+            case 0x66:
+            case 0x67:
+            case 0x68:
+            case 0x69:
+            case 0x6A:
+            case 0x6B:
+            case 0x6C:
+            case 0x6D:
+            case 0x6E:
+            case 0x6F:
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77:
+            {
+                return get_string(current & 0x1F);
+            }
 
-    Explicit type conversion between the JSON value and a compatible value
-    which is **not** [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible)
-    and **not** [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible).
-    The value is converted by calling the @ref json_serializer<ValueType>
-    `from_json()` method.
+            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
+            {
+                return get_string(get_number<uint8_t>());
+            }
 
-    The function is equivalent to executing
-    @code {.cpp}
-    return JSONSerializer<ValueTypeCV>::from_json(*this);
-    @endcode
+            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
+            {
+                return get_string(get_number<uint16_t>());
+            }
 
-    This overloads is chosen if:
-    - @a ValueType is not @ref basic_json and
-    - @ref json_serializer<ValueType> has a `from_json()` method of the form
-      `ValueType from_json(const @ref basic_json&)`
+            case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
+            {
+                return get_string(get_number<uint32_t>());
+            }
 
-    @note If @ref json_serializer<ValueType> has both overloads of
-    `from_json()`, this one is chosen.
+            case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
+            {
+                return get_string(get_number<uint64_t>());
+            }
 
-    @tparam ValueTypeCV the provided value type
-    @tparam ValueType the returned value type
+            case 0x7F: // UTF-8 string (indefinite length)
+            {
+                std::string result;
+                while (get() != 0xFF)
+                {
+                    check_eof();
+                    result.push_back(static_cast<char>(current));
+                }
+                return result;
+            }
 
-    @return copy of the JSON value, converted to @a ValueType
+            default:
+            {
+                std::stringstream ss;
+                ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
+                JSON_THROW(parse_error::create(113, chars_read, "expected a CBOR string; last byte: 0x" + ss.str()));
+            }
+        }
+    }
 
-    @throw what @ref json_serializer<ValueType> `from_json()` method throws
+    template<typename NumberType>
+    BasicJsonType get_cbor_array(const NumberType len)
+    {
+        BasicJsonType result = value_t::array;
+        std::generate_n(std::back_inserter(*result.m_value.array), len, [this]()
+        {
+            return parse_cbor_internal();
+        });
+        return result;
+    }
 
-    @since version 2.1.0
-    */
-    template <
-        typename ValueTypeCV,
-        typename ValueType = detail::uncvref_t<ValueTypeCV>,
-        detail::enable_if_t<not std::is_same<basic_json_t, ValueType>::value and
-                            detail::has_non_default_from_json<basic_json_t,
-                                    ValueType>::value, int> = 0 >
-    ValueType get() const noexcept(noexcept(
-                                       JSONSerializer<ValueTypeCV>::from_json(std::declval<const basic_json_t&>())))
+    template<typename NumberType>
+    BasicJsonType get_cbor_object(const NumberType len)
     {
-        static_assert(not std::is_reference<ValueTypeCV>::value,
-                      "get() cannot be used with reference types, you might want to use get_ref()");
-        return JSONSerializer<ValueTypeCV>::from_json(*this);
+        BasicJsonType result = value_t::object;
+        std::generate_n(std::inserter(*result.m_value.object,
+                                      result.m_value.object->end()),
+                        len, [this]()
+        {
+            get();
+            auto key = get_cbor_string();
+            auto val = parse_cbor_internal();
+            return std::make_pair(std::move(key), std::move(val));
+        });
+        return result;
     }
 
     /*!
-    @brief get a pointer value (explicit)
+    @brief reads a MessagePack string
 
-    Explicit pointer access to the internally stored JSON value. No copies are
-    made.
+    This function first reads starting bytes to determine the expected
+    string length and then copies this number of bytes into a string.
 
-    @warning The pointer becomes invalid if the underlying JSON object
-    changes.
+    @return string
 
-    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
-    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
-    @ref number_unsigned_t, or @ref number_float_t.
+    @throw parse_error.110 if input ended
+    @throw parse_error.113 if an unexpected byte is read
+    */
+    std::string get_msgpack_string()
+    {
+        check_eof();
 
-    @return pointer to the internally stored JSON value if the requested
-    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
+        switch (current)
+        {
+            // fixstr
+            case 0xA0:
+            case 0xA1:
+            case 0xA2:
+            case 0xA3:
+            case 0xA4:
+            case 0xA5:
+            case 0xA6:
+            case 0xA7:
+            case 0xA8:
+            case 0xA9:
+            case 0xAA:
+            case 0xAB:
+            case 0xAC:
+            case 0xAD:
+            case 0xAE:
+            case 0xAF:
+            case 0xB0:
+            case 0xB1:
+            case 0xB2:
+            case 0xB3:
+            case 0xB4:
+            case 0xB5:
+            case 0xB6:
+            case 0xB7:
+            case 0xB8:
+            case 0xB9:
+            case 0xBA:
+            case 0xBB:
+            case 0xBC:
+            case 0xBD:
+            case 0xBE:
+            case 0xBF:
+            {
+                return get_string(current & 0x1F);
+            }
 
-    @complexity Constant.
+            case 0xD9: // str 8
+            {
+                return get_string(get_number<uint8_t>());
+            }
 
-    @liveexample{The example below shows how pointers to internal values of a
-    JSON value can be requested. Note that no type conversions are made and a
-    `nullptr` is returned if the value and the requested pointer type does not
-    match.,get__PointerType}
+            case 0xDA: // str 16
+            {
+                return get_string(get_number<uint16_t>());
+            }
 
-    @sa @ref get_ptr() for explicit pointer-member access
+            case 0xDB: // str 32
+            {
+                return get_string(get_number<uint32_t>());
+            }
 
-    @since version 1.0.0
-    */
-    template<typename PointerType, typename std::enable_if<
-                 std::is_pointer<PointerType>::value, int>::type = 0>
-    PointerType get() noexcept
+            default:
+            {
+                std::stringstream ss;
+                ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
+                JSON_THROW(parse_error::create(113, chars_read,
+                                               "expected a MessagePack string; last byte: 0x" + ss.str()));
+            }
+        }
+    }
+
+    template<typename NumberType>
+    BasicJsonType get_msgpack_array(const NumberType len)
     {
-        // delegate the call to get_ptr
-        return get_ptr<PointerType>();
+        BasicJsonType result = value_t::array;
+        std::generate_n(std::back_inserter(*result.m_value.array), len, [this]()
+        {
+            return parse_msgpack_internal();
+        });
+        return result;
+    }
+
+    template<typename NumberType>
+    BasicJsonType get_msgpack_object(const NumberType len)
+    {
+        BasicJsonType result = value_t::object;
+        std::generate_n(std::inserter(*result.m_value.object,
+                                      result.m_value.object->end()),
+                        len, [this]()
+        {
+            get();
+            auto key = get_msgpack_string();
+            auto val = parse_msgpack_internal();
+            return std::make_pair(std::move(key), std::move(val));
+        });
+        return result;
     }
 
     /*!
-    @brief get a pointer value (explicit)
-    @copydoc get()
+    @brief check if input ended
+    @throw parse_error.110 if input ended
     */
-    template<typename PointerType, typename std::enable_if<
-                 std::is_pointer<PointerType>::value, int>::type = 0>
-    constexpr const PointerType get() const noexcept
+    void check_eof(const bool expect_eof = false) const
     {
-        // delegate the call to get_ptr
-        return get_ptr<PointerType>();
+        if (expect_eof)
+        {
+            if (JSON_UNLIKELY(current != std::char_traits<char>::eof()))
+            {
+                JSON_THROW(parse_error::create(110, chars_read, "expected end of input"));
+            }
+        }
+        else
+        {
+            if (JSON_UNLIKELY(current == std::char_traits<char>::eof()))
+            {
+                JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));
+            }
+        }
     }
 
-    /*!
-    @brief get a pointer value (implicit)
+  private:
+    /// input adapter
+    input_adapter_t ia = nullptr;
 
-    Implicit pointer access to the internally stored JSON value. No copies are
-    made.
+    /// the current character
+    int current = std::char_traits<char>::eof();
 
-    @warning Writing data to the pointee of the result yields an undefined
-    state.
+    /// the number of characters read
+    std::size_t chars_read = 0;
 
-    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
-    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
-    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
-    assertion.
+    /// whether we can assume little endianess
+    const bool is_little_endian = little_endianess();
+};
 
-    @return pointer to the internally stored JSON value if the requested
-    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
+/*!
+@brief serialization to CBOR and MessagePack values
+*/
+template<typename BasicJsonType, typename CharType>
+class binary_writer
+{
+  public:
+    /*!
+    @brief create a binary writer
 
-    @complexity Constant.
-
-    @liveexample{The example below shows how pointers to internal values of a
-    JSON value can be requested. Note that no type conversions are made and a
-    `nullptr` is returned if the value and the requested pointer type does not
-    match.,get_ptr}
-
-    @since version 1.0.0
-    */
-    template<typename PointerType, typename std::enable_if<
-                 std::is_pointer<PointerType>::value, int>::type = 0>
-    PointerType get_ptr() noexcept
-    {
-        // get the type of the PointerType (remove pointer and const)
-        using pointee_t = typename std::remove_const<typename
-                          std::remove_pointer<typename
-                          std::remove_const<PointerType>::type>::type>::type;
-        // make sure the type matches the allowed types
-        static_assert(
-            std::is_same<object_t, pointee_t>::value
-            or std::is_same<array_t, pointee_t>::value
-            or std::is_same<string_t, pointee_t>::value
-            or std::is_same<boolean_t, pointee_t>::value
-            or std::is_same<number_integer_t, pointee_t>::value
-            or std::is_same<number_unsigned_t, pointee_t>::value
-            or std::is_same<number_float_t, pointee_t>::value
-            , "incompatible pointer type");
-
-        // delegate the call to get_impl_ptr<>()
-        return get_impl_ptr(static_cast<PointerType>(nullptr));
-    }
+    @param[in] adapter  output adapter to write to
+    */
+    explicit binary_writer(output_adapter_t<CharType> adapter) : oa(adapter)
+    {
+        assert(oa);
+    }
 
     /*!
-    @brief get a pointer value (implicit)
-    @copydoc get_ptr()
+    @brief[in] j  JSON value to serialize
     */
-    template<typename PointerType, typename std::enable_if<
-                 std::is_pointer<PointerType>::value and
-                 std::is_const<typename std::remove_pointer<PointerType>::type>::value, int>::type = 0>
-    constexpr const PointerType get_ptr() const noexcept
+    void write_cbor(const BasicJsonType& j)
     {
-        // get the type of the PointerType (remove pointer and const)
-        using pointee_t = typename std::remove_const<typename
-                          std::remove_pointer<typename
-                          std::remove_const<PointerType>::type>::type>::type;
-        // make sure the type matches the allowed types
-        static_assert(
-            std::is_same<object_t, pointee_t>::value
-            or std::is_same<array_t, pointee_t>::value
-            or std::is_same<string_t, pointee_t>::value
-            or std::is_same<boolean_t, pointee_t>::value
-            or std::is_same<number_integer_t, pointee_t>::value
-            or std::is_same<number_unsigned_t, pointee_t>::value
-            or std::is_same<number_float_t, pointee_t>::value
-            , "incompatible pointer type");
+        switch (j.type())
+        {
+            case value_t::null:
+            {
+                oa->write_character(static_cast<CharType>(0xF6));
+                break;
+            }
 
-        // delegate the call to get_impl_ptr<>() const
-        return get_impl_ptr(static_cast<const PointerType>(nullptr));
-    }
+            case value_t::boolean:
+            {
+                oa->write_character(j.m_value.boolean
+                                    ? static_cast<CharType>(0xF5)
+                                    : static_cast<CharType>(0xF4));
+                break;
+            }
 
-    /*!
-    @brief get a reference value (implicit)
+            case value_t::number_integer:
+            {
+                if (j.m_value.number_integer >= 0)
+                {
+                    // CBOR does not differentiate between positive signed
+                    // integers and unsigned integers. Therefore, we used the
+                    // code from the value_t::number_unsigned case here.
+                    if (j.m_value.number_integer <= 0x17)
+                    {
+                        write_number(static_cast<uint8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer <= (std::numeric_limits<uint8_t>::max)())
+                    {
+                        oa->write_character(static_cast<CharType>(0x18));
+                        write_number(static_cast<uint8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer <= (std::numeric_limits<uint16_t>::max)())
+                    {
+                        oa->write_character(static_cast<CharType>(0x19));
+                        write_number(static_cast<uint16_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer <= (std::numeric_limits<uint32_t>::max)())
+                    {
+                        oa->write_character(static_cast<CharType>(0x1A));
+                        write_number(static_cast<uint32_t>(j.m_value.number_integer));
+                    }
+                    else
+                    {
+                        oa->write_character(static_cast<CharType>(0x1B));
+                        write_number(static_cast<uint64_t>(j.m_value.number_integer));
+                    }
+                }
+                else
+                {
+                    // The conversions below encode the sign in the first
+                    // byte, and the value is converted to a positive number.
+                    const auto positive_number = -1 - j.m_value.number_integer;
+                    if (j.m_value.number_integer >= -24)
+                    {
+                        write_number(static_cast<uint8_t>(0x20 + positive_number));
+                    }
+                    else if (positive_number <= (std::numeric_limits<uint8_t>::max)())
+                    {
+                        oa->write_character(static_cast<CharType>(0x38));
+                        write_number(static_cast<uint8_t>(positive_number));
+                    }
+                    else if (positive_number <= (std::numeric_limits<uint16_t>::max)())
+                    {
+                        oa->write_character(static_cast<CharType>(0x39));
+                        write_number(static_cast<uint16_t>(positive_number));
+                    }
+                    else if (positive_number <= (std::numeric_limits<uint32_t>::max)())
+                    {
+                        oa->write_character(static_cast<CharType>(0x3A));
+                        write_number(static_cast<uint32_t>(positive_number));
+                    }
+                    else
+                    {
+                        oa->write_character(static_cast<CharType>(0x3B));
+                        write_number(static_cast<uint64_t>(positive_number));
+                    }
+                }
+                break;
+            }
 
-    Implicit reference access to the internally stored JSON value. No copies
-    are made.
+            case value_t::number_unsigned:
+            {
+                if (j.m_value.number_unsigned <= 0x17)
+                {
+                    write_number(static_cast<uint8_t>(j.m_value.number_unsigned));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
+                {
+                    oa->write_character(static_cast<CharType>(0x18));
+                    write_number(static_cast<uint8_t>(j.m_value.number_unsigned));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
+                {
+                    oa->write_character(static_cast<CharType>(0x19));
+                    write_number(static_cast<uint16_t>(j.m_value.number_unsigned));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
+                {
+                    oa->write_character(static_cast<CharType>(0x1A));
+                    write_number(static_cast<uint32_t>(j.m_value.number_unsigned));
+                }
+                else
+                {
+                    oa->write_character(static_cast<CharType>(0x1B));
+                    write_number(static_cast<uint64_t>(j.m_value.number_unsigned));
+                }
+                break;
+            }
 
-    @warning Writing data to the referee of the result yields an undefined
-    state.
+            case value_t::number_float: // Double-Precision Float
+            {
+                oa->write_character(static_cast<CharType>(0xFB));
+                write_number(j.m_value.number_float);
+                break;
+            }
 
-    @tparam ReferenceType reference type; must be a reference to @ref array_t,
-    @ref object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, or
-    @ref number_float_t. Enforced by static assertion.
+            case value_t::string:
+            {
+                // step 1: write control byte and the string length
+                const auto N = j.m_value.string->size();
+                if (N <= 0x17)
+                {
+                    write_number(static_cast<uint8_t>(0x60 + N));
+                }
+                else if (N <= 0xFF)
+                {
+                    oa->write_character(static_cast<CharType>(0x78));
+                    write_number(static_cast<uint8_t>(N));
+                }
+                else if (N <= 0xFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0x79));
+                    write_number(static_cast<uint16_t>(N));
+                }
+                else if (N <= 0xFFFFFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0x7A));
+                    write_number(static_cast<uint32_t>(N));
+                }
+                // LCOV_EXCL_START
+                else if (N <= 0xFFFFFFFFFFFFFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0x7B));
+                    write_number(static_cast<uint64_t>(N));
+                }
+                // LCOV_EXCL_STOP
 
-    @return reference to the internally stored JSON value if the requested
-    reference type @a ReferenceType fits to the JSON value; throws
-    type_error.303 otherwise
+                // step 2: write the string
+                oa->write_characters(
+                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
+                    j.m_value.string->size());
+                break;
+            }
 
-    @throw type_error.303 in case passed type @a ReferenceType is incompatible
-    with the stored JSON value; see example below
+            case value_t::array:
+            {
+                // step 1: write control byte and the array size
+                const auto N = j.m_value.array->size();
+                if (N <= 0x17)
+                {
+                    write_number(static_cast<uint8_t>(0x80 + N));
+                }
+                else if (N <= 0xFF)
+                {
+                    oa->write_character(static_cast<CharType>(0x98));
+                    write_number(static_cast<uint8_t>(N));
+                }
+                else if (N <= 0xFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0x99));
+                    write_number(static_cast<uint16_t>(N));
+                }
+                else if (N <= 0xFFFFFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0x9A));
+                    write_number(static_cast<uint32_t>(N));
+                }
+                // LCOV_EXCL_START
+                else if (N <= 0xFFFFFFFFFFFFFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0x9B));
+                    write_number(static_cast<uint64_t>(N));
+                }
+                // LCOV_EXCL_STOP
 
-    @complexity Constant.
+                // step 2: write each element
+                for (const auto& el : *j.m_value.array)
+                {
+                    write_cbor(el);
+                }
+                break;
+            }
 
-    @liveexample{The example shows several calls to `get_ref()`.,get_ref}
+            case value_t::object:
+            {
+                // step 1: write control byte and the object size
+                const auto N = j.m_value.object->size();
+                if (N <= 0x17)
+                {
+                    write_number(static_cast<uint8_t>(0xA0 + N));
+                }
+                else if (N <= 0xFF)
+                {
+                    oa->write_character(static_cast<CharType>(0xB8));
+                    write_number(static_cast<uint8_t>(N));
+                }
+                else if (N <= 0xFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0xB9));
+                    write_number(static_cast<uint16_t>(N));
+                }
+                else if (N <= 0xFFFFFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0xBA));
+                    write_number(static_cast<uint32_t>(N));
+                }
+                // LCOV_EXCL_START
+                else if (N <= 0xFFFFFFFFFFFFFFFF)
+                {
+                    oa->write_character(static_cast<CharType>(0xBB));
+                    write_number(static_cast<uint64_t>(N));
+                }
+                // LCOV_EXCL_STOP
 
-    @since version 1.1.0
-    */
-    template<typename ReferenceType, typename std::enable_if<
-                 std::is_reference<ReferenceType>::value, int>::type = 0>
-    ReferenceType get_ref()
-    {
-        // delegate call to get_ref_impl
-        return get_ref_impl<ReferenceType>(*this);
+                // step 2: write each element
+                for (const auto& el : *j.m_value.object)
+                {
+                    write_cbor(el.first);
+                    write_cbor(el.second);
+                }
+                break;
+            }
+
+            default:
+                break;
+        }
     }
 
     /*!
-    @brief get a reference value (implicit)
-    @copydoc get_ref()
+    @brief[in] j  JSON value to serialize
     */
-    template<typename ReferenceType, typename std::enable_if<
-                 std::is_reference<ReferenceType>::value and
-                 std::is_const<typename std::remove_reference<ReferenceType>::type>::value, int>::type = 0>
-    ReferenceType get_ref() const
+    void write_msgpack(const BasicJsonType& j)
     {
-        // delegate call to get_ref_impl
-        return get_ref_impl<ReferenceType>(*this);
-    }
-
-    /*!
-    @brief get a value (implicit)
-
-    Implicit type conversion between the JSON value and a compatible value.
-    The call is realized by calling @ref get() const.
-
-    @tparam ValueType non-pointer type compatible to the JSON value, for
-    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
-    `std::vector` types for JSON arrays. The character type of @ref string_t
-    as well as an initializer list of this type is excluded to avoid
-    ambiguities as these types implicitly convert to `std::string`.
-
-    @return copy of the JSON value, converted to type @a ValueType
-
-    @throw type_error.302 in case passed type @a ValueType is incompatible
-    to the JSON value type (e.g., the JSON value is of type boolean, but a
-    string is requested); see example below
+        switch (j.type())
+        {
+            case value_t::null: // nil
+            {
+                oa->write_character(static_cast<CharType>(0xC0));
+                break;
+            }
 
-    @complexity Linear in the size of the JSON value.
+            case value_t::boolean: // true and false
+            {
+                oa->write_character(j.m_value.boolean
+                                    ? static_cast<CharType>(0xC3)
+                                    : static_cast<CharType>(0xC2));
+                break;
+            }
 
-    @liveexample{The example below shows several conversions from JSON values
-    to other types. There a few things to note: (1) Floating-point numbers can
-    be converted to integers\, (2) A JSON array can be converted to a standard
-    `std::vector<short>`\, (3) A JSON object can be converted to C++
-    associative containers such as `std::unordered_map<std::string\,
-    json>`.,operator__ValueType}
-
-    @since version 1.0.0
-    */
-    template < typename ValueType, typename std::enable_if <
-                   not std::is_pointer<ValueType>::value and
-                   not std::is_same<ValueType, typename string_t::value_type>::value
-#ifndef _MSC_VER  // fix for issue #167 operator<< ambiguity under VS2015
-                   and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
-#endif
-#if defined(_MSC_VER) && _MSC_VER >1900 && defined(_HAS_CXX17) && _HAS_CXX17 == 1 // fix for issue #464
-                   and not std::is_same<ValueType, typename std::string_view>::value
-#endif
-                   , int >::type = 0 >
-    operator ValueType() const
-    {
-        // delegate the call to get<>() const
-        return get<ValueType>();
-    }
-
-    /// @}
+            case value_t::number_integer:
+            {
+                if (j.m_value.number_integer >= 0)
+                {
+                    // MessagePack does not differentiate between positive
+                    // signed integers and unsigned integers. Therefore, we used
+                    // the code from the value_t::number_unsigned case here.
+                    if (j.m_value.number_unsigned < 128)
+                    {
+                        // positive fixnum
+                        write_number(static_cast<uint8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
+                    {
+                        // uint 8
+                        oa->write_character(static_cast<CharType>(0xCC));
+                        write_number(static_cast<uint8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
+                    {
+                        // uint 16
+                        oa->write_character(static_cast<CharType>(0xCD));
+                        write_number(static_cast<uint16_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
+                    {
+                        // uint 32
+                        oa->write_character(static_cast<CharType>(0xCE));
+                        write_number(static_cast<uint32_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)())
+                    {
+                        // uint 64
+                        oa->write_character(static_cast<CharType>(0xCF));
+                        write_number(static_cast<uint64_t>(j.m_value.number_integer));
+                    }
+                }
+                else
+                {
+                    if (j.m_value.number_integer >= -32)
+                    {
+                        // negative fixnum
+                        write_number(static_cast<int8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer >= (std::numeric_limits<int8_t>::min)() and
+                             j.m_value.number_integer <= (std::numeric_limits<int8_t>::max)())
+                    {
+                        // int 8
+                        oa->write_character(static_cast<CharType>(0xD0));
+                        write_number(static_cast<int8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer >= (std::numeric_limits<int16_t>::min)() and
+                             j.m_value.number_integer <= (std::numeric_limits<int16_t>::max)())
+                    {
+                        // int 16
+                        oa->write_character(static_cast<CharType>(0xD1));
+                        write_number(static_cast<int16_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer >= (std::numeric_limits<int32_t>::min)() and
+                             j.m_value.number_integer <= (std::numeric_limits<int32_t>::max)())
+                    {
+                        // int 32
+                        oa->write_character(static_cast<CharType>(0xD2));
+                        write_number(static_cast<int32_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer >= (std::numeric_limits<int64_t>::min)() and
+                             j.m_value.number_integer <= (std::numeric_limits<int64_t>::max)())
+                    {
+                        // int 64
+                        oa->write_character(static_cast<CharType>(0xD3));
+                        write_number(static_cast<int64_t>(j.m_value.number_integer));
+                    }
+                }
+                break;
+            }
 
+            case value_t::number_unsigned:
+            {
+                if (j.m_value.number_unsigned < 128)
+                {
+                    // positive fixnum
+                    write_number(static_cast<uint8_t>(j.m_value.number_integer));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
+                {
+                    // uint 8
+                    oa->write_character(static_cast<CharType>(0xCC));
+                    write_number(static_cast<uint8_t>(j.m_value.number_integer));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
+                {
+                    // uint 16
+                    oa->write_character(static_cast<CharType>(0xCD));
+                    write_number(static_cast<uint16_t>(j.m_value.number_integer));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
+                {
+                    // uint 32
+                    oa->write_character(static_cast<CharType>(0xCE));
+                    write_number(static_cast<uint32_t>(j.m_value.number_integer));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)())
+                {
+                    // uint 64
+                    oa->write_character(static_cast<CharType>(0xCF));
+                    write_number(static_cast<uint64_t>(j.m_value.number_integer));
+                }
+                break;
+            }
 
-    ////////////////////
-    // element access //
-    ////////////////////
+            case value_t::number_float: // float 64
+            {
+                oa->write_character(static_cast<CharType>(0xCB));
+                write_number(j.m_value.number_float);
+                break;
+            }
 
-    /// @name element access
-    /// Access to the JSON value.
-    /// @{
+            case value_t::string:
+            {
+                // step 1: write control byte and the string length
+                const auto N = j.m_value.string->size();
+                if (N <= 31)
+                {
+                    // fixstr
+                    write_number(static_cast<uint8_t>(0xA0 | N));
+                }
+                else if (N <= 255)
+                {
+                    // str 8
+                    oa->write_character(static_cast<CharType>(0xD9));
+                    write_number(static_cast<uint8_t>(N));
+                }
+                else if (N <= 65535)
+                {
+                    // str 16
+                    oa->write_character(static_cast<CharType>(0xDA));
+                    write_number(static_cast<uint16_t>(N));
+                }
+                else if (N <= 4294967295)
+                {
+                    // str 32
+                    oa->write_character(static_cast<CharType>(0xDB));
+                    write_number(static_cast<uint32_t>(N));
+                }
 
-    /*!
-    @brief access specified array element with bounds checking
+                // step 2: write the string
+                oa->write_characters(
+                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
+                    j.m_value.string->size());
+                break;
+            }
 
-    Returns a reference to the element at specified location @a idx, with
-    bounds checking.
+            case value_t::array:
+            {
+                // step 1: write control byte and the array size
+                const auto N = j.m_value.array->size();
+                if (N <= 15)
+                {
+                    // fixarray
+                    write_number(static_cast<uint8_t>(0x90 | N));
+                }
+                else if (N <= 0xFFFF)
+                {
+                    // array 16
+                    oa->write_character(static_cast<CharType>(0xDC));
+                    write_number(static_cast<uint16_t>(N));
+                }
+                else if (N <= 0xFFFFFFFF)
+                {
+                    // array 32
+                    oa->write_character(static_cast<CharType>(0xDD));
+                    write_number(static_cast<uint32_t>(N));
+                }
 
-    @param[in] idx  index of the element to access
+                // step 2: write each element
+                for (const auto& el : *j.m_value.array)
+                {
+                    write_msgpack(el);
+                }
+                break;
+            }
 
-    @return reference to the element at index @a idx
+            case value_t::object:
+            {
+                // step 1: write control byte and the object size
+                const auto N = j.m_value.object->size();
+                if (N <= 15)
+                {
+                    // fixmap
+                    write_number(static_cast<uint8_t>(0x80 | (N & 0xF)));
+                }
+                else if (N <= 65535)
+                {
+                    // map 16
+                    oa->write_character(static_cast<CharType>(0xDE));
+                    write_number(static_cast<uint16_t>(N));
+                }
+                else if (N <= 4294967295)
+                {
+                    // map 32
+                    oa->write_character(static_cast<CharType>(0xDF));
+                    write_number(static_cast<uint32_t>(N));
+                }
 
-    @throw type_error.304 if the JSON value is not an array; in this case,
-    calling `at` with an index makes no sense. See example below.
-    @throw out_of_range.401 if the index @a idx is out of range of the array;
-    that is, `idx >= size()`. See example below.
+                // step 2: write each element
+                for (const auto& el : *j.m_value.object)
+                {
+                    write_msgpack(el.first);
+                    write_msgpack(el.second);
+                }
+                break;
+            }
 
-    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
-    changes in the JSON value.
+            default:
+                break;
+        }
+    }
 
-    @complexity Constant.
+  private:
+    /*
+    @brief write a number to output input
 
-    @since version 1.0.0
+    @param[in] n number of type @a NumberType
+    @tparam NumberType the type of the number
 
-    @liveexample{The example below shows how array elements can be read and
-    written using `at()`. It also demonstrates the different exceptions that
-    can be thrown.,at__size_type}
+    @note This function needs to respect the system's endianess, because bytes
+          in CBOR and MessagePack are stored in network order (big endian) and
+          therefore need reordering on little endian systems.
     */
-    reference at(size_type idx)
+    template<typename NumberType> void write_number(NumberType n)
     {
-        // at only works for arrays
-        if (is_array())
-        {
-            JSON_TRY
-            {
-                return m_value.array->at(idx);
-            }
-            JSON_CATCH (std::out_of_range&)
-            {
-                // create better exception explanation
-                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
-            }
-        }
-        else
+        // step 1: write number to array of length NumberType
+        std::array<CharType, sizeof(NumberType)> vec;
+        std::memcpy(vec.data(), &n, sizeof(NumberType));
+
+        // step 2: write array to output (with possible reordering)
+        if (is_little_endian)
         {
-            JSON_THROW(type_error::create(304, "cannot use at() with " + type_name()));
+            // reverse byte order prior to conversion if necessary
+            std::reverse(vec.begin(), vec.end());
         }
+
+        oa->write_characters(vec.data(), sizeof(NumberType));
     }
 
-    /*!
-    @brief access specified array element with bounds checking
+  private:
+    /// whether we can assume little endianess
+    const bool is_little_endian = binary_reader<BasicJsonType>::little_endianess();
 
-    Returns a const reference to the element at specified location @a idx,
-    with bounds checking.
+    /// the output
+    output_adapter_t<CharType> oa = nullptr;
+};
 
-    @param[in] idx  index of the element to access
+///////////////////
+// serialization //
+///////////////////
 
-    @return const reference to the element at index @a idx
+template<typename BasicJsonType>
+class serializer
+{
+    using string_t = typename BasicJsonType::string_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+  public:
+    /*!
+    @param[in] s  output stream to serialize to
+    @param[in] ichar  indentation character to use
+    */
+    serializer(output_adapter_t<char> s, const char ichar)
+        : o(std::move(s)), loc(std::localeconv()),
+          thousands_sep(loc->thousands_sep == nullptr ? '\0' : * (loc->thousands_sep)),
+          decimal_point(loc->decimal_point == nullptr ? '\0' : * (loc->decimal_point)),
+          indent_char(ichar), indent_string(512, indent_char) {}
 
-    @throw type_error.304 if the JSON value is not an array; in this case,
-    calling `at` with an index makes no sense. See example below.
-    @throw out_of_range.401 if the index @a idx is out of range of the array;
-    that is, `idx >= size()`. See example below.
+    // delete because of pointer members
+    serializer(const serializer&) = delete;
+    serializer& operator=(const serializer&) = delete;
 
-    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
-    changes in the JSON value.
+    /*!
+    @brief internal implementation of the serialization function
 
-    @complexity Constant.
+    This function is called by the public member function dump and organizes
+    the serialization internally. The indentation level is propagated as
+    additional parameter. In case of arrays and objects, the function is
+    called recursively.
 
-    @since version 1.0.0
+    - strings and object keys are escaped using `escape_string()`
+    - integer numbers are converted implicitly via `operator<<`
+    - floating-point numbers are converted to a string using `"%g"` format
 
-    @liveexample{The example below shows how array elements can be read using
-    `at()`. It also demonstrates the different exceptions that can be thrown.,
-    at__size_type_const}
+    @param[in] val             value to serialize
+    @param[in] pretty_print    whether the output shall be pretty-printed
+    @param[in] indent_step     the indent level
+    @param[in] current_indent  the current indent level (only used internally)
     */
-    const_reference at(size_type idx) const
+    void dump(const BasicJsonType& val, const bool pretty_print,
+              const bool ensure_ascii,
+              const unsigned int indent_step,
+              const unsigned int current_indent = 0)
     {
-        // at only works for arrays
-        if (is_array())
+        switch (val.m_type)
         {
-            JSON_TRY
-            {
-                return m_value.array->at(idx);
-            }
-            JSON_CATCH (std::out_of_range&)
+            case value_t::object:
             {
-                // create better exception explanation
-                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
-            }
-        }
-        else
-        {
-            JSON_THROW(type_error::create(304, "cannot use at() with " + type_name()));
-        }
-    }
+                if (val.m_value.object->empty())
+                {
+                    o->write_characters("{}", 2);
+                    return;
+                }
 
-    /*!
-    @brief access specified object element with bounds checking
+                if (pretty_print)
+                {
+                    o->write_characters("{\n", 2);
 
-    Returns a reference to the element at with specified key @a key, with
-    bounds checking.
+                    // variable to hold indentation for recursive calls
+                    const auto new_indent = current_indent + indent_step;
+                    if (JSON_UNLIKELY(indent_string.size() < new_indent))
+                    {
+                        indent_string.resize(indent_string.size() * 2, ' ');
+                    }
 
-    @param[in] key  key of the element to access
+                    // first n-1 elements
+                    auto i = val.m_value.object->cbegin();
+                    for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
+                    {
+                        o->write_characters(indent_string.c_str(), new_indent);
+                        o->write_character('\"');
+                        dump_escaped(i->first, ensure_ascii);
+                        o->write_characters("\": ", 3);
+                        dump(i->second, true, ensure_ascii, indent_step, new_indent);
+                        o->write_characters(",\n", 2);
+                    }
 
-    @return reference to the element at key @a key
+                    // last element
+                    assert(i != val.m_value.object->cend());
+                    assert(std::next(i) == val.m_value.object->cend());
+                    o->write_characters(indent_string.c_str(), new_indent);
+                    o->write_character('\"');
+                    dump_escaped(i->first, ensure_ascii);
+                    o->write_characters("\": ", 3);
+                    dump(i->second, true, ensure_ascii, indent_step, new_indent);
 
-    @throw type_error.304 if the JSON value is not an object; in this case,
-    calling `at` with a key makes no sense. See example below.
-    @throw out_of_range.403 if the key @a key is is not stored in the object;
-    that is, `find(key) == end()`. See example below.
-
-    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
-    changes in the JSON value.
+                    o->write_character('\n');
+                    o->write_characters(indent_string.c_str(), current_indent);
+                    o->write_character('}');
+                }
+                else
+                {
+                    o->write_character('{');
 
-    @complexity Logarithmic in the size of the container.
+                    // first n-1 elements
+                    auto i = val.m_value.object->cbegin();
+                    for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
+                    {
+                        o->write_character('\"');
+                        dump_escaped(i->first, ensure_ascii);
+                        o->write_characters("\":", 2);
+                        dump(i->second, false, ensure_ascii, indent_step, current_indent);
+                        o->write_character(',');
+                    }
 
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
-    @sa @ref value() for access by value with a default value
+                    // last element
+                    assert(i != val.m_value.object->cend());
+                    assert(std::next(i) == val.m_value.object->cend());
+                    o->write_character('\"');
+                    dump_escaped(i->first, ensure_ascii);
+                    o->write_characters("\":", 2);
+                    dump(i->second, false, ensure_ascii, indent_step, current_indent);
 
-    @since version 1.0.0
+                    o->write_character('}');
+                }
 
-    @liveexample{The example below shows how object elements can be read and
-    written using `at()`. It also demonstrates the different exceptions that
-    can be thrown.,at__object_t_key_type}
-    */
-    reference at(const typename object_t::key_type& key)
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            JSON_TRY
-            {
-                return m_value.object->at(key);
+                return;
             }
-            JSON_CATCH (std::out_of_range&)
+
+            case value_t::array:
             {
-                // create better exception explanation
-                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
-            }
-        }
-        else
-        {
-            JSON_THROW(type_error::create(304, "cannot use at() with " + type_name()));
-        }
-    }
+                if (val.m_value.array->empty())
+                {
+                    o->write_characters("[]", 2);
+                    return;
+                }
 
-    /*!
-    @brief access specified object element with bounds checking
+                if (pretty_print)
+                {
+                    o->write_characters("[\n", 2);
 
-    Returns a const reference to the element at with specified key @a key,
-    with bounds checking.
+                    // variable to hold indentation for recursive calls
+                    const auto new_indent = current_indent + indent_step;
+                    if (JSON_UNLIKELY(indent_string.size() < new_indent))
+                    {
+                        indent_string.resize(indent_string.size() * 2, ' ');
+                    }
 
-    @param[in] key  key of the element to access
+                    // first n-1 elements
+                    for (auto i = val.m_value.array->cbegin();
+                            i != val.m_value.array->cend() - 1; ++i)
+                    {
+                        o->write_characters(indent_string.c_str(), new_indent);
+                        dump(*i, true, ensure_ascii, indent_step, new_indent);
+                        o->write_characters(",\n", 2);
+                    }
 
-    @return const reference to the element at key @a key
+                    // last element
+                    assert(not val.m_value.array->empty());
+                    o->write_characters(indent_string.c_str(), new_indent);
+                    dump(val.m_value.array->back(), true, ensure_ascii, indent_step, new_indent);
 
-    @throw type_error.304 if the JSON value is not an object; in this case,
-    calling `at` with a key makes no sense. See example below.
-    @throw out_of_range.403 if the key @a key is is not stored in the object;
-    that is, `find(key) == end()`. See example below.
+                    o->write_character('\n');
+                    o->write_characters(indent_string.c_str(), current_indent);
+                    o->write_character(']');
+                }
+                else
+                {
+                    o->write_character('[');
 
-    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
-    changes in the JSON value.
+                    // first n-1 elements
+                    for (auto i = val.m_value.array->cbegin();
+                            i != val.m_value.array->cend() - 1; ++i)
+                    {
+                        dump(*i, false, ensure_ascii, indent_step, current_indent);
+                        o->write_character(',');
+                    }
 
-    @complexity Logarithmic in the size of the container.
+                    // last element
+                    assert(not val.m_value.array->empty());
+                    dump(val.m_value.array->back(), false, ensure_ascii, indent_step, current_indent);
 
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
-    @sa @ref value() for access by value with a default value
+                    o->write_character(']');
+                }
 
-    @since version 1.0.0
+                return;
+            }
 
-    @liveexample{The example below shows how object elements can be read using
-    `at()`. It also demonstrates the different exceptions that can be thrown.,
-    at__object_t_key_type_const}
-    */
-    const_reference at(const typename object_t::key_type& key) const
-    {
-        // at only works for objects
-        if (is_object())
-        {
-            JSON_TRY
+            case value_t::string:
             {
-                return m_value.object->at(key);
+                o->write_character('\"');
+                dump_escaped(*val.m_value.string, ensure_ascii);
+                o->write_character('\"');
+                return;
             }
-            JSON_CATCH (std::out_of_range&)
+
+            case value_t::boolean:
             {
-                // create better exception explanation
-                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
+                if (val.m_value.boolean)
+                {
+                    o->write_characters("true", 4);
+                }
+                else
+                {
+                    o->write_characters("false", 5);
+                }
+                return;
             }
-        }
-        else
-        {
-            JSON_THROW(type_error::create(304, "cannot use at() with " + type_name()));
-        }
-    }
-
-    /*!
-    @brief access specified array element
-
-    Returns a reference to the element at specified location @a idx.
-
-    @note If @a idx is beyond the range of the array (i.e., `idx >= size()`),
-    then the array is silently filled up with `null` values to make `idx` a
-    valid reference to the last stored element.
-
-    @param[in] idx  index of the element to access
-
-    @return reference to the element at index @a idx
-
-    @throw type_error.305 if the JSON value is not an array or null; in that
-    cases, using the [] operator with an index makes no sense.
 
-    @complexity Constant if @a idx is in the range of the array. Otherwise
-    linear in `idx - size()`.
+            case value_t::number_integer:
+            {
+                dump_integer(val.m_value.number_integer);
+                return;
+            }
 
-    @liveexample{The example below shows how array elements can be read and
-    written using `[]` operator. Note the addition of `null`
-    values.,operatorarray__size_type}
+            case value_t::number_unsigned:
+            {
+                dump_integer(val.m_value.number_unsigned);
+                return;
+            }
 
-    @since version 1.0.0
-    */
-    reference operator[](size_type idx)
-    {
-        // implicitly convert null value to an empty array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value.array = create<array_t>();
-            assert_invariant();
-        }
+            case value_t::number_float:
+            {
+                dump_float(val.m_value.number_float);
+                return;
+            }
 
-        // operator[] only works for arrays
-        if (is_array())
-        {
-            // fill up array with null values if given idx is outside range
-            if (idx >= m_value.array->size())
+            case value_t::discarded:
             {
-                m_value.array->insert(m_value.array->end(),
-                                      idx - m_value.array->size() + 1,
-                                      basic_json());
+                o->write_characters("<discarded>", 11);
+                return;
             }
 
-            return m_value.array->operator[](idx);
+            case value_t::null:
+            {
+                o->write_characters("null", 4);
+                return;
+            }
         }
-
-        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
     }
 
+  private:
     /*!
-    @brief access specified array element
-
-    Returns a const reference to the element at specified location @a idx.
-
-    @param[in] idx  index of the element to access
+    @brief returns the number of expected bytes following in UTF-8 string
 
-    @return const reference to the element at index @a idx
-
-    @throw type_error.305 if the JSON value is not an array; in that cases,
-    using the [] operator with an index makes no sense.
+    @param[in]  u  the first byte of a UTF-8 string
+    @return  the number of expected bytes following
+    */
+    static constexpr std::size_t bytes_following(const uint8_t u)
+    {
+        return ((u <= 127) ? 0
+                : ((192 <= u and u <= 223) ? 1
+                   : ((224 <= u and u <= 239) ? 2
+                      : ((240 <= u and u <= 247) ? 3 : std::string::npos))));
+    }
 
-    @complexity Constant.
+    /*!
+    @brief calculates the extra space to escape a JSON string
 
-    @liveexample{The example below shows how array elements can be read using
-    the `[]` operator.,operatorarray__size_type_const}
+    @param[in] s  the string to escape
+    @param[in] ensure_ascii  whether to escape non-ASCII characters with
+                             \uXXXX sequences
+    @return the number of characters required to escape string @a s
 
-    @since version 1.0.0
+    @complexity Linear in the length of string @a s.
     */
-    const_reference operator[](size_type idx) const
+    static std::size_t extra_space(const string_t& s,
+                                   const bool ensure_ascii) noexcept
     {
-        // const operator[] only works for arrays
-        if (is_array())
-        {
-            return m_value.array->operator[](idx);
-        }
+        std::size_t res = 0;
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
-    }
+        for (std::size_t i = 0; i < s.size(); ++i)
+        {
+            switch (s[i])
+            {
+                // control characters that can be escaped with a backslash
+                case '"':
+                case '\\':
+                case '\b':
+                case '\f':
+                case '\n':
+                case '\r':
+                case '\t':
+                {
+                    // from c (1 byte) to \x (2 bytes)
+                    res += 1;
+                    break;
+                }
 
-    /*!
-    @brief access specified object element
+                // control characters that need \uxxxx escaping
+                case 0x00:
+                case 0x01:
+                case 0x02:
+                case 0x03:
+                case 0x04:
+                case 0x05:
+                case 0x06:
+                case 0x07:
+                case 0x0B:
+                case 0x0E:
+                case 0x0F:
+                case 0x10:
+                case 0x11:
+                case 0x12:
+                case 0x13:
+                case 0x14:
+                case 0x15:
+                case 0x16:
+                case 0x17:
+                case 0x18:
+                case 0x19:
+                case 0x1A:
+                case 0x1B:
+                case 0x1C:
+                case 0x1D:
+                case 0x1E:
+                case 0x1F:
+                {
+                    // from c (1 byte) to \uxxxx (6 bytes)
+                    res += 5;
+                    break;
+                }
 
-    Returns a reference to the element at with specified key @a key.
+                default:
+                {
+                    if (ensure_ascii and (s[i] & 0x80 or s[i] == 0x7F))
+                    {
+                        const auto bytes = bytes_following(static_cast<uint8_t>(s[i]));
+                        // invalid characters will be detected by throw_if_invalid_utf8
+                        assert (bytes != std::string::npos);
 
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
+                        if (bytes == 3)
+                        {
+                            // codepoints that need 4 bytes (i.e., 3 additional
+                            // bytes) in UTF-8 need a surrogate pair when \u
+                            // escaping is used: from 4 bytes to \uxxxx\uxxxx
+                            // (12 bytes)
+                            res += (12 - bytes - 1);
+                        }
+                        else
+                        {
+                            // from x bytes to \uxxxx (6 bytes)
+                            res += (6 - bytes - 1);
+                        }
 
-    @param[in] key  key of the element to access
+                        // skip the additional bytes
+                        i += bytes;
+                    }
+                    break;
+                }
+            }
+        }
 
-    @return reference to the element at key @a key
+        return res;
+    }
 
-    @throw type_error.305 if the JSON value is not an object or null; in that
-    cases, using the [] operator with a key makes no sense.
+    static void escape_codepoint(int codepoint, string_t& result, std::size_t& pos)
+    {
+        // expecting a proper codepoint
+        assert(0x00 <= codepoint and codepoint <= 0x10FFFF);
 
-    @complexity Logarithmic in the size of the container.
+        // the last written character was the backslash before the 'u'
+        assert(result[pos] == '\\');
 
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
+        // write the 'u'
+        result[++pos] = 'u';
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
+        // convert a number 0..15 to its hex representation (0..f)
+        static const std::array<char, 16> hexify =
+        {
+            {
+                '0', '1', '2', '3', '4', '5', '6', '7',
+                '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
+            }
+        };
 
-    @since version 1.0.0
-    */
-    reference operator[](const typename object_t::key_type& key)
-    {
-        // implicitly convert null value to an empty object
-        if (is_null())
+        if (codepoint < 0x10000)
         {
-            m_type = value_t::object;
-            m_value.object = create<object_t>();
-            assert_invariant();
+            // codepoints U+0000..U+FFFF can be represented as \uxxxx.
+            result[++pos] = hexify[(codepoint >> 12) & 0x0F];
+            result[++pos] = hexify[(codepoint >> 8) & 0x0F];
+            result[++pos] = hexify[(codepoint >> 4) & 0x0F];
+            result[++pos] = hexify[codepoint & 0x0F];
         }
-
-        // operator[] only works for objects
-        if (is_object())
+        else
         {
-            return m_value.object->operator[](key);
+            // codepoints U+10000..U+10FFFF need a surrogate pair to be
+            // represented as \uxxxx\uxxxx.
+            // http://www.unicode.org/faq/utf_bom.html#utf16-4
+            codepoint -= 0x10000;
+            const int high_surrogate = 0xD800 | ((codepoint >> 10) & 0x3FF);
+            const int low_surrogate = 0xDC00 | (codepoint & 0x3FF);
+            result[++pos] = hexify[(high_surrogate >> 12) & 0x0F];
+            result[++pos] = hexify[(high_surrogate >> 8) & 0x0F];
+            result[++pos] = hexify[(high_surrogate >> 4) & 0x0F];
+            result[++pos] = hexify[high_surrogate & 0x0F];
+            ++pos;  // backslash is already in output
+            result[++pos] = 'u';
+            result[++pos] = hexify[(low_surrogate >> 12) & 0x0F];
+            result[++pos] = hexify[(low_surrogate >> 8) & 0x0F];
+            result[++pos] = hexify[(low_surrogate >> 4) & 0x0F];
+            result[++pos] = hexify[low_surrogate & 0x0F];
         }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
+        ++pos;
     }
 
     /*!
-    @brief read-only access specified object element
+    @brief dump escaped string
 
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
+    Escape a string by replacing certain special characters by a sequence of an
+    escape character (backslash) and another character and other control
+    characters by a sequence of "\u" followed by a four-digit hex
+    representation. The escaped string is written to output stream @a o.
 
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
+    @param[in] s  the string to escape
+    @param[in] ensure_ascii  whether to escape non-ASCII characters with
+                             \uXXXX sequences
 
-    @param[in] key  key of the element to access
+    @complexity Linear in the length of string @a s.
+    */
+    void dump_escaped(const string_t& s, const bool ensure_ascii) const
+    {
+        throw_if_invalid_utf8(s);
 
-    @return const reference to the element at key @a key
+        const auto space = extra_space(s, ensure_ascii);
+        if (space == 0)
+        {
+            o->write_characters(s.c_str(), s.size());
+            return;
+        }
 
-    @pre The element with key @a key must exist. **This precondition is
-         enforced with an assertion.**
+        // create a result string of necessary size
+        string_t result(s.size() + space, '\\');
+        std::size_t pos = 0;
 
-    @throw type_error.305 if the JSON value is not an object; in that cases,
-    using the [] operator with a key makes no sense.
+        for (std::size_t i = 0; i < s.size(); ++i)
+        {
+            switch (s[i])
+            {
+                case '"': // quotation mark (0x22)
+                {
+                    result[pos + 1] = '"';
+                    pos += 2;
+                    break;
+                }
 
-    @complexity Logarithmic in the size of the container.
+                case '\\': // reverse solidus (0x5C)
+                {
+                    // nothing to change
+                    pos += 2;
+                    break;
+                }
 
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
+                case '\b': // backspace (0x08)
+                {
+                    result[pos + 1] = 'b';
+                    pos += 2;
+                    break;
+                }
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
+                case '\f': // formfeed (0x0C)
+                {
+                    result[pos + 1] = 'f';
+                    pos += 2;
+                    break;
+                }
 
-    @since version 1.0.0
-    */
-    const_reference operator[](const typename object_t::key_type& key) const
-    {
-        // const operator[] only works for objects
-        if (is_object())
-        {
-            assert(m_value.object->find(key) != m_value.object->end());
-            return m_value.object->find(key)->second;
-        }
+                case '\n': // newline (0x0A)
+                {
+                    result[pos + 1] = 'n';
+                    pos += 2;
+                    break;
+                }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
-    }
+                case '\r': // carriage return (0x0D)
+                {
+                    result[pos + 1] = 'r';
+                    pos += 2;
+                    break;
+                }
 
-    /*!
-    @brief access specified object element
+                case '\t': // horizontal tab (0x09)
+                {
+                    result[pos + 1] = 't';
+                    pos += 2;
+                    break;
+                }
 
-    Returns a reference to the element at with specified key @a key.
+                default:
+                {
+                    // escape control characters (0x00..0x1F) or, if
+                    // ensure_ascii parameter is used, non-ASCII characters
+                    if ((0x00 <= s[i] and s[i] <= 0x1F) or
+                            (ensure_ascii and (s[i] & 0x80 or s[i] == 0x7F)))
+                    {
+                        const auto bytes = bytes_following(static_cast<uint8_t>(s[i]));
+                        // invalid characters will be detected by throw_if_invalid_utf8
+                        assert (bytes != std::string::npos);
 
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
+                        // check that the additional bytes are present
+                        assert(i + bytes < s.size());
 
-    @param[in] key  key of the element to access
+                        // to use \uxxxx escaping, we first need to calculate
+                        // the codepoint from the UTF-8 bytes
+                        int codepoint = 0;
 
-    @return reference to the element at key @a key
+                        // bytes is unsigned type:
+                        assert(bytes <= 3);
+                        switch (bytes)
+                        {
+                            case 0:
+                            {
+                                codepoint = s[i] & 0xFF;
+                                break;
+                            }
 
-    @throw type_error.305 if the JSON value is not an object or null; in that
-    cases, using the [] operator with a key makes no sense.
+                            case 1:
+                            {
+                                codepoint = ((s[i] & 0x3F) << 6)
+                                            + (s[i + 1] & 0x7F);
+                                break;
+                            }
 
-    @complexity Logarithmic in the size of the container.
+                            case 2:
+                            {
+                                codepoint = ((s[i] & 0x1F) << 12)
+                                            + ((s[i + 1] & 0x7F) << 6)
+                                            + (s[i + 2] & 0x7F);
+                                break;
+                            }
 
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
+                            case 3:
+                            {
+                                codepoint = ((s[i] & 0xF) << 18)
+                                            + ((s[i + 1] & 0x7F) << 12)
+                                            + ((s[i + 2] & 0x7F) << 6)
+                                            + (s[i + 3] & 0x7F);
+                                break;
+                            }
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
+                            default:
+                                break;  // LCOV_EXCL_LINE
+                        }
 
-    @since version 1.0.0
-    */
-    template<typename T, std::size_t n>
-    reference operator[](T * (&key)[n])
-    {
-        return operator[](static_cast<const T>(key));
+                        escape_codepoint(codepoint, result, pos);
+                        i += bytes;
+                    }
+                    else
+                    {
+                        // all other characters are added as-is
+                        result[pos++] = s[i];
+                    }
+                    break;
+                }
+            }
+        }
+
+        assert(pos == result.size());
+        o->write_characters(result.c_str(), result.size());
     }
 
     /*!
-    @brief read-only access specified object element
-
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
-
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
-
-    @note This function is required for compatibility reasons with Clang.
+    @brief dump an integer
 
-    @param[in] key  key of the element to access
+    Dump a given integer to output stream @a o. Works internally with
+    @a number_buffer.
 
-    @return const reference to the element at key @a key
+    @param[in] x  integer number (signed or unsigned) to dump
+    @tparam NumberType either @a number_integer_t or @a number_unsigned_t
+    */
+    template<typename NumberType, detail::enable_if_t<
+                 std::is_same<NumberType, number_unsigned_t>::value or
+                 std::is_same<NumberType, number_integer_t>::value,
+                 int> = 0>
+    void dump_integer(NumberType x)
+    {
+        // special case for "0"
+        if (x == 0)
+        {
+            o->write_character('0');
+            return;
+        }
 
-    @throw type_error.305 if the JSON value is not an object; in that cases,
-    using the [] operator with a key makes no sense.
+        const bool is_negative = (x <= 0) and (x != 0);  // see issue #755
+        std::size_t i = 0;
 
-    @complexity Logarithmic in the size of the container.
+        while (x != 0)
+        {
+            // spare 1 byte for '\0'
+            assert(i < number_buffer.size() - 1);
 
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
+            const auto digit = std::labs(static_cast<long>(x % 10));
+            number_buffer[i++] = static_cast<char>('0' + digit);
+            x /= 10;
+        }
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
+        if (is_negative)
+        {
+            // make sure there is capacity for the '-'
+            assert(i < number_buffer.size() - 2);
+            number_buffer[i++] = '-';
+        }
 
-    @since version 1.0.0
-    */
-    template<typename T, std::size_t n>
-    const_reference operator[](T * (&key)[n]) const
-    {
-        return operator[](static_cast<const T>(key));
+        std::reverse(number_buffer.begin(), number_buffer.begin() + i);
+        o->write_characters(number_buffer.data(), i);
     }
 
     /*!
-    @brief access specified object element
+    @brief dump a floating-point number
 
-    Returns a reference to the element at with specified key @a key.
+    Dump a given floating-point number to output stream @a o. Works internally
+    with @a number_buffer.
 
-    @note If @a key is not found in the object, then it is silently added to
-    the object and filled with a `null` value to make `key` a valid reference.
-    In case the value was `null` before, it is converted to an object.
+    @param[in] x  floating-point number to dump
+    */
+    void dump_float(number_float_t x)
+    {
+        // NaN / inf
+        if (not std::isfinite(x) or std::isnan(x))
+        {
+            o->write_characters("null", 4);
+            return;
+        }
 
-    @param[in] key  key of the element to access
+        // get number of digits for a text -> float -> text round-trip
+        static constexpr auto d = std::numeric_limits<number_float_t>::digits10;
 
-    @return reference to the element at key @a key
+        // the actual conversion
+        std::ptrdiff_t len = snprintf(number_buffer.data(), number_buffer.size(), "%.*g", d, x);
 
-    @throw type_error.305 if the JSON value is not an object or null; in that
-    cases, using the [] operator with a key makes no sense.
+        // negative value indicates an error
+        assert(len > 0);
+        // check if buffer was large enough
+        assert(static_cast<std::size_t>(len) < number_buffer.size());
 
-    @complexity Logarithmic in the size of the container.
+        // erase thousands separator
+        if (thousands_sep != '\0')
+        {
+            const auto end = std::remove(number_buffer.begin(),
+                                         number_buffer.begin() + len, thousands_sep);
+            std::fill(end, number_buffer.end(), '\0');
+            assert((end - number_buffer.begin()) <= len);
+            len = (end - number_buffer.begin());
+        }
 
-    @liveexample{The example below shows how object elements can be read and
-    written using the `[]` operator.,operatorarray__key_type}
+        // convert decimal point to '.'
+        if (decimal_point != '\0' and decimal_point != '.')
+        {
+            const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
+            if (dec_pos != number_buffer.end())
+            {
+                *dec_pos = '.';
+            }
+        }
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
+        o->write_characters(number_buffer.data(), static_cast<std::size_t>(len));
 
-    @since version 1.1.0
-    */
-    template<typename T>
-    reference operator[](T* key)
-    {
-        // implicitly convert null to object
-        if (is_null())
+        // determine if need to append ".0"
+        const bool value_is_int_like =
+            std::none_of(number_buffer.begin(), number_buffer.begin() + len + 1,
+                         [](char c)
         {
-            m_type = value_t::object;
-            m_value = value_t::object;
-            assert_invariant();
-        }
+            return (c == '.' or c == 'e');
+        });
 
-        // at only works for objects
-        if (is_object())
+        if (value_is_int_like)
         {
-            return m_value.object->operator[](key);
+            o->write_characters(".0", 2);
         }
-
-        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
     }
 
     /*!
-    @brief read-only access specified object element
-
-    Returns a const reference to the element at with specified key @a key. No
-    bounds checking is performed.
-
-    @warning If the element with key @a key does not exist, the behavior is
-    undefined.
+    @brief check whether a string is UTF-8 encoded
 
-    @param[in] key  key of the element to access
+    The function checks each byte of a string whether it is UTF-8 encoded. The
+    result of the check is stored in the @a state parameter. The function must
+    be called initially with state 0 (accept). State 1 means the string must
+    be rejected, because the current byte is not allowed. If the string is
+    completely processed, but the state is non-zero, the string ended
+    prematurely; that is, the last byte indicated more bytes should have
+    followed.
 
-    @return const reference to the element at key @a key
+    @param[in,out] state  the state of the decoding
+    @param[in] byte       next byte to decode
 
-    @pre The element with key @a key must exist. **This precondition is
-         enforced with an assertion.**
+    @note The function has been edited: a std::array is used and the code
+          point is not calculated.
 
-    @throw type_error.305 if the JSON value is not an object; in that cases,
-    using the [] operator with a key makes no sense.
+    @copyright Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
+    @sa http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
+    */
+    static void decode(uint8_t& state, const uint8_t byte)
+    {
+        static const std::array<uint8_t, 400> utf8d =
+        {
+            {
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 00..1F
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20..3F
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 40..5F
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 60..7F
+                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 80..9F
+                7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // A0..BF
+                8, 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // C0..DF
+                0xA, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x4, 0x3, 0x3, // E0..EF
+                0xB, 0x6, 0x6, 0x6, 0x5, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, // F0..FF
+                0x0, 0x1, 0x2, 0x3, 0x5, 0x8, 0x7, 0x1, 0x1, 0x1, 0x4, 0x6, 0x1, 0x1, 0x1, 0x1, // s0..s0
+                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, // s1..s2
+                1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, // s3..s4
+                1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, // s5..s6
+                1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 // s7..s8
+            }
+        };
 
-    @complexity Logarithmic in the size of the container.
+        const uint8_t type = utf8d[byte];
+        state = utf8d[256u + state * 16u + type];
+    }
 
-    @liveexample{The example below shows how object elements can be read using
-    the `[]` operator.,operatorarray__key_type_const}
+    /*!
+    @brief throw an exception if a string is not UTF-8 encoded
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref value() for access by value with a default value
+    @param[in] str  UTF-8 string to check
+    @throw type_error.316 if passed string is not UTF-8 encoded
 
-    @since version 1.1.0
+    @since version 3.0.0
     */
-    template<typename T>
-    const_reference operator[](T* key) const
+    static void throw_if_invalid_utf8(const std::string& str)
     {
-        // at only works for objects
-        if (is_object())
+        // start with state 0 (= accept)
+        uint8_t state = 0;
+
+        for (size_t i = 0; i < str.size(); ++i)
         {
-            assert(m_value.object->find(key) != m_value.object->end());
-            return m_value.object->find(key)->second;
+            const auto byte = static_cast<uint8_t>(str[i]);
+            decode(state, byte);
+            if (state == 1)
+            {
+                // state 1 means reject
+                std::stringstream ss;
+                ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << static_cast<int>(byte);
+                JSON_THROW(type_error::create(316, "invalid UTF-8 byte at index " + std::to_string(i) + ": 0x" + ss.str()));
+            }
         }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with " + type_name()));
+        if (state != 0)
+        {
+            // we finish reading, but do not accept: string was incomplete
+            std::stringstream ss;
+            ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << static_cast<int>(static_cast<uint8_t>(str.back()));
+            JSON_THROW(type_error::create(316, "incomplete UTF-8 string; last byte: 0x" + ss.str()));
+        }
     }
 
-    /*!
-    @brief access specified object element with default value
-
-    Returns either a copy of an object's element at the specified key @a key
-    or a given default value if no element with key @a key exists.
+  private:
+    /// the output of the serializer
+    output_adapter_t<char> o = nullptr;
 
-    The function is basically equivalent to executing
-    @code {.cpp}
-    try {
-        return at(key);
-    } catch(out_of_range) {
-        return default_value;
-    }
-    @endcode
+    /// a (hopefully) large enough character buffer
+    std::array<char, 64> number_buffer{{}};
 
-    @note Unlike @ref at(const typename object_t::key_type&), this function
-    does not throw if the given key @a key was not found.
+    /// the locale
+    const std::lconv* loc = nullptr;
+    /// the locale's thousand separator character
+    const char thousands_sep = '\0';
+    /// the locale's decimal point character
+    const char decimal_point = '\0';
 
-    @note Unlike @ref operator[](const typename object_t::key_type& key), this
-    function does not implicitly add an element to the position defined by @a
-    key. This function is furthermore also applicable to const objects.
+    /// the indentation character
+    const char indent_char;
 
-    @param[in] key  key of the element to access
-    @param[in] default_value  the value to return if @a key is not found
+    /// the indentation string
+    string_t indent_string;
+};
 
-    @tparam ValueType type compatible to JSON values, for instance `int` for
-    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
-    JSON arrays. Note the type of the expected value at @a key and the default
-    value @a default_value must be compatible.
+template<typename BasicJsonType>
+class json_ref
+{
+  public:
+    using value_type = BasicJsonType;
 
-    @return copy of the element at key @a key or @a default_value if @a key
-    is not found
+    json_ref(value_type&& value)
+        : owned_value(std::move(value)), value_ref(&owned_value), is_rvalue(true)
+    {}
 
-    @throw type_error.306 if the JSON value is not an objec; in that cases,
-    using `value()` with a key makes no sense.
+    json_ref(const value_type& value)
+        : value_ref(const_cast<value_type*>(&value)), is_rvalue(false)
+    {}
 
-    @complexity Logarithmic in the size of the container.
+    json_ref(std::initializer_list<json_ref> init)
+        : owned_value(init), value_ref(&owned_value), is_rvalue(true)
+    {}
 
-    @liveexample{The example below shows how object elements can be queried
-    with a default value.,basic_json__value}
+    template<class... Args>
+    json_ref(Args&& ... args)
+        : owned_value(std::forward<Args>(args)...), value_ref(&owned_value), is_rvalue(true)
+    {}
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
-    with range checking
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
-    access by reference
+    // class should be movable only
+    json_ref(json_ref&&) = default;
+    json_ref(const json_ref&) = delete;
+    json_ref& operator=(const json_ref&) = delete;
 
-    @since version 1.0.0
-    */
-    template<class ValueType, typename std::enable_if<
-                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
-    ValueType value(const typename object_t::key_type& key, ValueType default_value) const
+    value_type moved_or_copied() const
     {
-        // at only works for objects
-        if (is_object())
-        {
-            // if key is found, return value and given default value otherwise
-            const auto it = find(key);
-            if (it != end())
-            {
-                return *it;
-            }
-
-            return default_value;
-        }
-        else
+        if (is_rvalue)
         {
-            JSON_THROW(type_error::create(306, "cannot use value() with " + type_name()));
+            return std::move(*value_ref);
         }
+        return *value_ref;
     }
 
-    /*!
-    @brief overload for a default value of type const char*
-    @copydoc basic_json::value(const typename object_t::key_type&, ValueType) const
-    */
-    string_t value(const typename object_t::key_type& key, const char* default_value) const
+    value_type const& operator*() const
     {
-        return value(key, string_t(default_value));
+        return *static_cast<value_type const*>(value_ref);
     }
 
-    /*!
-    @brief access specified object element via JSON Pointer with default value
-
-    Returns either a copy of an object's element at the specified key @a key
-    or a given default value if no element with key @a key exists.
-
-    The function is basically equivalent to executing
-    @code {.cpp}
-    try {
-        return at(ptr);
-    } catch(out_of_range) {
-        return default_value;
+    value_type const* operator->() const
+    {
+        return static_cast<value_type const*>(value_ref);
     }
-    @endcode
-
-    @note Unlike @ref at(const json_pointer&), this function does not throw
-    if the given key @a key was not found.
 
-    @param[in] ptr  a JSON pointer to the element to access
-    @param[in] default_value  the value to return if @a ptr found no value
+  private:
+    mutable value_type owned_value = nullptr;
+    value_type* value_ref = nullptr;
+    const bool is_rvalue;
+};
 
-    @tparam ValueType type compatible to JSON values, for instance `int` for
-    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
-    JSON arrays. Note the type of the expected value at @a key and the default
-    value @a default_value must be compatible.
+} // namespace detail
 
-    @return copy of the element at key @a key or @a default_value if @a key
-    is not found
+/// namespace to hold default `to_json` / `from_json` functions
+namespace
+{
+constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value;
+constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
+}
 
-    @throw type_error.306 if the JSON value is not an objec; in that cases,
-    using `value()` with a key makes no sense.
 
-    @complexity Logarithmic in the size of the container.
+/*!
+@brief default JSONSerializer template argument
 
-    @liveexample{The example below shows how object elements can be queried
-    with a default value.,basic_json__value_ptr}
+This serializer ignores the template arguments and uses ADL
+([argument-dependent lookup](http://en.cppreference.com/w/cpp/language/adl))
+for serialization.
+*/
+template<typename, typename>
+struct adl_serializer
+{
+    /*!
+    @brief convert a JSON value to any value type
 
-    @sa @ref operator[](const json_pointer&) for unchecked access by reference
+    This function is usually called by the `get()` function of the
+    @ref basic_json class (either explicit or via conversion operators).
 
-    @since version 2.0.2
+    @param[in] j         JSON value to read from
+    @param[in,out] val  value to write to
     */
-    template<class ValueType, typename std::enable_if<
-                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
-    ValueType value(const json_pointer& ptr, ValueType default_value) const
+    template<typename BasicJsonType, typename ValueType>
+    static void from_json(BasicJsonType&& j, ValueType& val) noexcept(
+        noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), val)))
     {
-        // at only works for objects
-        if (is_object())
-        {
-            // if pointer resolves a value, return it or use default value
-            JSON_TRY
-            {
-                return ptr.get_checked(this);
-            }
-            JSON_CATCH (out_of_range&)
-            {
-                return default_value;
-            }
-        }
-
-        JSON_THROW(type_error::create(306, "cannot use value() with " + type_name()));
+        ::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
     }
 
     /*!
-    @brief overload for a default value of type const char*
-    @copydoc basic_json::value(const json_pointer&, ValueType) const
+    @brief convert any value type to a JSON value
+
+    This function is usually called by the constructors of the @ref basic_json
+    class.
+
+    @param[in,out] j  JSON value to write to
+    @param[in] val     value to read from
     */
-    string_t value(const json_pointer& ptr, const char* default_value) const
+    template<typename BasicJsonType, typename ValueType>
+    static void to_json(BasicJsonType& j, ValueType&& val) noexcept(
+        noexcept(::nlohmann::to_json(j, std::forward<ValueType>(val))))
     {
-        return value(ptr, string_t(default_value));
+        ::nlohmann::to_json(j, std::forward<ValueType>(val));
     }
+};
 
-    /*!
-    @brief access the first element
+/*!
+@brief JSON Pointer
 
-    Returns a reference to the first element in the container. For a JSON
-    container `c`, the expression `c.front()` is equivalent to `*c.begin()`.
+A JSON pointer defines a string syntax for identifying a specific value
+within a JSON document. It can be used with functions `at` and
+`operator[]`. Furthermore, JSON pointers are the base for JSON patches.
 
-    @return In case of a structured type (array or object), a reference to the
-    first element is returned. In case of number, string, or boolean values, a
-    reference to the value is returned.
+@sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
 
-    @complexity Constant.
+@since version 2.0.0
+*/
+class json_pointer
+{
+    /// allow basic_json to access private members
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    friend class basic_json;
 
-    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
-    or an empty array or object (undefined behavior, **guarded by
-    assertions**).
-    @post The JSON value remains unchanged.
+  public:
+    /*!
+    @brief create JSON pointer
 
-    @throw invalid_iterator.214 when called on `null` value
+    Create a JSON pointer according to the syntax described in
+    [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3).
 
-    @liveexample{The following code shows an example for `front()`.,front}
+    @param[in] s  string representing the JSON pointer; if omitted, the empty
+                  string is assumed which references the whole JSON value
 
-    @sa @ref back() -- access the last element
+    @throw parse_error.107 if the given JSON pointer @a s is nonempty and
+    does not begin with a slash (`/`); see example below
 
-    @since version 1.0.0
-    */
-    reference front()
-    {
-        return *begin();
-    }
+    @throw parse_error.108 if a tilde (`~`) in the given JSON pointer @a s
+    is not followed by `0` (representing `~`) or `1` (representing `/`);
+    see example below
 
-    /*!
-    @copydoc basic_json::front()
+    @liveexample{The example shows the construction several valid JSON
+    pointers as well as the exceptional behavior.,json_pointer}
+
+    @since version 2.0.0
     */
-    const_reference front() const
-    {
-        return *cbegin();
-    }
+    explicit json_pointer(const std::string& s = "") : reference_tokens(split(s)) {}
 
     /*!
-    @brief access the last element
+    @brief return a string representation of the JSON pointer
 
-    Returns a reference to the last element in the container. For a JSON
-    container `c`, the expression `c.back()` is equivalent to
+    @invariant For each JSON pointer `ptr`, it holds:
     @code {.cpp}
-    auto tmp = c.end();
-    --tmp;
-    return *tmp;
+    ptr == json_pointer(ptr.to_string());
     @endcode
 
-    @return In case of a structured type (array or object), a reference to the
-    last element is returned. In case of number, string, or boolean values, a
-    reference to the value is returned.
+    @return a string representation of the JSON pointer
 
-    @complexity Constant.
+    @liveexample{The example shows the result of `to_string`.,
+    json_pointer__to_string}
 
-    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
-    or an empty array or object (undefined behavior, **guarded by
-    assertions**).
-    @post The JSON value remains unchanged.
+    @since version 2.0.0
+    */
+    std::string to_string() const noexcept
+    {
+        return std::accumulate(reference_tokens.begin(), reference_tokens.end(),
+                               std::string{},
+                               [](const std::string & a, const std::string & b)
+        {
+            return a + "/" + escape(b);
+        });
+    }
 
-    @throw invalid_iterator.214 when called on a `null` value. See example
-    below.
+    /// @copydoc to_string()
+    operator std::string() const
+    {
+        return to_string();
+    }
 
-    @liveexample{The following code shows an example for `back()`.,back}
+    /*!
+    @param[in] s  reference token to be converted into an array index
 
-    @sa @ref front() -- access the first element
+    @return integer representation of @a s
 
-    @since version 1.0.0
+    @throw out_of_range.404 if string @a s could not be converted to an integer
     */
-    reference back()
+    static int array_index(const std::string& s)
     {
-        auto tmp = end();
-        --tmp;
-        return *tmp;
+        size_t processed_chars = 0;
+        const int res = std::stoi(s, &processed_chars);
+
+        // check if the string was completely read
+        if (JSON_UNLIKELY(processed_chars != s.size()))
+        {
+            JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + s + "'"));
+        }
+
+        return res;
     }
 
+  private:
     /*!
-    @copydoc basic_json::back()
+    @brief remove and return last reference pointer
+    @throw out_of_range.405 if JSON pointer has no parent
     */
-    const_reference back() const
+    std::string pop_back()
     {
-        auto tmp = cend();
-        --tmp;
-        return *tmp;
+        if (JSON_UNLIKELY(is_root()))
+        {
+            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent"));
+        }
+
+        auto last = reference_tokens.back();
+        reference_tokens.pop_back();
+        return last;
     }
 
-    /*!
-    @brief remove element given an iterator
+    /// return whether pointer points to the root document
+    bool is_root() const
+    {
+        return reference_tokens.empty();
+    }
 
-    Removes the element specified by iterator @a pos. The iterator @a pos must
-    be valid and dereferenceable. Thus the `end()` iterator (which is valid,
-    but is not dereferenceable) cannot be used as a value for @a pos.
+    json_pointer top() const
+    {
+        if (JSON_UNLIKELY(is_root()))
+        {
+            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent"));
+        }
 
-    If called on a primitive type other than `null`, the resulting JSON value
-    will be `null`.
+        json_pointer result = *this;
+        result.reference_tokens = {reference_tokens[0]};
+        return result;
+    }
 
-    @param[in] pos iterator to the element to remove
-    @return Iterator following the last removed element. If the iterator @a
-    pos refers to the last element, the `end()` iterator is returned.
+    /*!
+    @brief create and return a reference to the pointed to value
 
-    @tparam IteratorType an @ref iterator or @ref const_iterator
+    @complexity Linear in the number of reference tokens.
 
-    @post Invalidates iterators and references at or after the point of the
-    erase, including the `end()` iterator.
+    @throw parse_error.109 if array index is not a number
+    @throw type_error.313 if value cannot be unflattened
+    */
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    NLOHMANN_BASIC_JSON_TPL& get_and_create(NLOHMANN_BASIC_JSON_TPL& j) const;
 
-    @throw type_error.307 if called on a `null` value; example: `"cannot use
-    erase() with null"`
-    @throw invalid_iterator.202 if called on an iterator which does not belong
-    to the current JSON value; example: `"iterator does not fit current
-    value"`
-    @throw invalid_iterator.205 if called on a primitive type with invalid
-    iterator (i.e., any iterator which is not `begin()`); example: `"iterator
-    out of range"`
+    /*!
+    @brief return a reference to the pointed to value
 
-    @complexity The complexity depends on the type:
-    - objects: amortized constant
-    - arrays: linear in distance between @a pos and the end of the container
-    - strings: linear in the length of the string
-    - other types: constant
+    @note This version does not throw if a value is not present, but tries to
+          create nested values instead. For instance, calling this function
+          with pointer `"/this/that"` on a null value is equivalent to calling
+          `operator[]("this").operator[]("that")` on that value, effectively
+          changing the null value to an object.
 
-    @liveexample{The example shows the result of `erase()` for different JSON
-    types.,erase__IteratorType}
+    @param[in] ptr  a JSON value
 
-    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
+    @return reference to the JSON value pointed to by the JSON pointer
 
-    @since version 1.0.0
+    @complexity Linear in the length of the JSON pointer.
+
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.404  if the JSON pointer can not be resolved
     */
-    template<class IteratorType, typename std::enable_if<
-                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
-                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
-             = 0>
-    IteratorType erase(IteratorType pos)
-    {
-        // make sure iterator fits the current value
-        if (this != pos.m_object)
-        {
-            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
-        }
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    NLOHMANN_BASIC_JSON_TPL& get_unchecked(NLOHMANN_BASIC_JSON_TPL* ptr) const;
 
-        IteratorType result = end();
+    /*!
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.402  if the array index '-' is used
+    @throw out_of_range.404  if the JSON pointer can not be resolved
+    */
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    NLOHMANN_BASIC_JSON_TPL& get_checked(NLOHMANN_BASIC_JSON_TPL* ptr) const;
 
-        switch (m_type)
-        {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
-            {
-                if (not pos.m_it.primitive_iterator.is_begin())
-                {
-                    JSON_THROW(invalid_iterator::create(205, "iterator out of range"));
-                }
+    /*!
+    @brief return a const reference to the pointed to value
 
-                if (is_string())
-                {
-                    AllocatorType<string_t> alloc;
-                    alloc.destroy(m_value.string);
-                    alloc.deallocate(m_value.string, 1);
-                    m_value.string = nullptr;
-                }
-
-                m_type = value_t::null;
-                assert_invariant();
-                break;
-            }
-
-            case value_t::object:
-            {
-                result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator);
-                break;
-            }
-
-            case value_t::array:
-            {
-                result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator);
-                break;
-            }
+    @param[in] ptr  a JSON value
 
-            default:
-            {
-                JSON_THROW(type_error::create(307, "cannot use erase() with " + type_name()));
-            }
-        }
+    @return const reference to the JSON value pointed to by the JSON
+    pointer
 
-        return result;
-    }
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.402  if the array index '-' is used
+    @throw out_of_range.404  if the JSON pointer can not be resolved
+    */
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    const NLOHMANN_BASIC_JSON_TPL& get_unchecked(const NLOHMANN_BASIC_JSON_TPL* ptr) const;
 
     /*!
-    @brief remove elements given an iterator range
-
-    Removes the element specified by the range `[first; last)`. The iterator
-    @a first does not need to be dereferenceable if `first == last`: erasing
-    an empty range is a no-op.
-
-    If called on a primitive type other than `null`, the resulting JSON value
-    will be `null`.
-
-    @param[in] first iterator to the beginning of the range to remove
-    @param[in] last iterator past the end of the range to remove
-    @return Iterator following the last removed element. If the iterator @a
-    second refers to the last element, the `end()` iterator is returned.
-
-    @tparam IteratorType an @ref iterator or @ref const_iterator
-
-    @post Invalidates iterators and references at or after the point of the
-    erase, including the `end()` iterator.
-
-    @throw type_error.307 if called on a `null` value; example: `"cannot use
-    erase() with null"`
-    @throw invalid_iterator.203 if called on iterators which does not belong
-    to the current JSON value; example: `"iterators do not fit current value"`
-    @throw invalid_iterator.204 if called on a primitive type with invalid
-    iterators (i.e., if `first != begin()` and `last != end()`); example:
-    `"iterators out of range"`
-
-    @complexity The complexity depends on the type:
-    - objects: `log(size()) + std::distance(first, last)`
-    - arrays: linear in the distance between @a first and @a last, plus linear
-      in the distance between @a last and end of the container
-    - strings: linear in the length of the string
-    - other types: constant
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.402  if the array index '-' is used
+    @throw out_of_range.404  if the JSON pointer can not be resolved
+    */
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    const NLOHMANN_BASIC_JSON_TPL& get_checked(const NLOHMANN_BASIC_JSON_TPL* ptr) const;
 
-    @liveexample{The example shows the result of `erase()` for different JSON
-    types.,erase__IteratorType_IteratorType}
+    /*!
+    @brief split the string input to reference tokens
 
-    @sa @ref erase(IteratorType) -- removes the element at a given position
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
+    @note This function is only called by the json_pointer constructor.
+          All exceptions below are documented there.
 
-    @since version 1.0.0
+    @throw parse_error.107  if the pointer is not empty or begins with '/'
+    @throw parse_error.108  if character '~' is not followed by '0' or '1'
     */
-    template<class IteratorType, typename std::enable_if<
-                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
-                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
-             = 0>
-    IteratorType erase(IteratorType first, IteratorType last)
+    static std::vector<std::string> split(const std::string& reference_string)
     {
-        // make sure iterator fits the current value
-        if (this != first.m_object or this != last.m_object)
+        std::vector<std::string> result;
+
+        // special case: empty reference string -> no reference tokens
+        if (reference_string.empty())
         {
-            JSON_THROW(invalid_iterator::create(203, "iterators do not fit current value"));
+            return result;
         }
 
-        IteratorType result = end();
+        // check if nonempty reference string begins with slash
+        if (JSON_UNLIKELY(reference_string[0] != '/'))
+        {
+            JSON_THROW(detail::parse_error::create(107, 1,
+                                                   "JSON pointer must be empty or begin with '/' - was: '" +
+                                                   reference_string + "'"));
+        }
 
-        switch (m_type)
+        // extract the reference tokens:
+        // - slash: position of the last read slash (or end of string)
+        // - start: position after the previous slash
+        for (
+            // search for the first slash after the first character
+            std::size_t slash = reference_string.find_first_of('/', 1),
+            // set the beginning of the first reference token
+            start = 1;
+            // we can stop if start == string::npos+1 = 0
+            start != 0;
+            // set the beginning of the next reference token
+            // (will eventually be 0 if slash == std::string::npos)
+            start = slash + 1,
+            // find next slash
+            slash = reference_string.find_first_of('/', start))
         {
-            case value_t::boolean:
-            case value_t::number_float:
-            case value_t::number_integer:
-            case value_t::number_unsigned:
-            case value_t::string:
+            // use the text between the beginning of the reference token
+            // (start) and the last slash (slash).
+            auto reference_token = reference_string.substr(start, slash - start);
+
+            // check reference tokens are properly escaped
+            for (std::size_t pos = reference_token.find_first_of('~');
+                    pos != std::string::npos;
+                    pos = reference_token.find_first_of('~', pos + 1))
             {
-                if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end())
-                {
-                    JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
-                }
+                assert(reference_token[pos] == '~');
 
-                if (is_string())
+                // ~ must be followed by 0 or 1
+                if (JSON_UNLIKELY(pos == reference_token.size() - 1 or
+                                  (reference_token[pos + 1] != '0' and
+                                   reference_token[pos + 1] != '1')))
                 {
-                    AllocatorType<string_t> alloc;
-                    alloc.destroy(m_value.string);
-                    alloc.deallocate(m_value.string, 1);
-                    m_value.string = nullptr;
+                    JSON_THROW(detail::parse_error::create(108, 0, "escape character '~' must be followed with '0' or '1'"));
                 }
-
-                m_type = value_t::null;
-                assert_invariant();
-                break;
-            }
-
-            case value_t::object:
-            {
-                result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator,
-                                              last.m_it.object_iterator);
-                break;
-            }
-
-            case value_t::array:
-            {
-                result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator,
-                                             last.m_it.array_iterator);
-                break;
             }
 
-            default:
-            {
-                JSON_THROW(type_error::create(307, "cannot use erase() with " + type_name()));
-            }
+            // finally, store the reference token
+            unescape(reference_token);
+            result.push_back(reference_token);
         }
 
         return result;
     }
 
     /*!
-    @brief remove element from a JSON object given a key
-
-    Removes elements from a JSON object with the key value @a key.
-
-    @param[in] key value of the elements to remove
+    @brief replace all occurrences of a substring by another string
 
-    @return Number of elements removed. If @a ObjectType is the default
-    `std::map` type, the return value will always be `0` (@a key was not
-    found) or `1` (@a key was found).
-
-    @post References and iterators to the erased elements are invalidated.
-    Other references and iterators are not affected.
-
-    @throw type_error.307 when called on a type other than JSON object;
-    example: `"cannot use erase() with null"`
-
-    @complexity `log(size()) + count(key)`
-
-    @liveexample{The example shows the effect of `erase()`.,erase__key_type}
+    @param[in,out] s  the string to manipulate; changed so that all
+                   occurrences of @a f are replaced with @a t
+    @param[in]     f  the substring to replace with @a t
+    @param[in]     t  the string to replace @a f
 
-    @sa @ref erase(IteratorType) -- removes the element at a given position
-    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const size_type) -- removes the element from an array at
-    the given index
+    @pre The search string @a f must not be empty. **This precondition is
+    enforced with an assertion.**
 
-    @since version 1.0.0
+    @since version 2.0.0
     */
-    size_type erase(const typename object_t::key_type& key)
+    static void replace_substring(std::string& s, const std::string& f,
+                                  const std::string& t)
     {
-        // this erase only works for objects
-        if (is_object())
-        {
-            return m_value.object->erase(key);
-        }
-
-        JSON_THROW(type_error::create(307, "cannot use erase() with " + type_name()));
+        assert(not f.empty());
+        for (auto pos = s.find(f);                // find first occurrence of f
+                pos != std::string::npos;         // make sure f was found
+                s.replace(pos, f.size(), t),      // replace with t, and
+                pos = s.find(f, pos + t.size()))  // find next occurrence of f
+        {}
     }
 
-    /*!
-    @brief remove element from a JSON array given an index
-
-    Removes element from a JSON array at the index @a idx.
-
-    @param[in] idx index of the element to remove
-
-    @throw type_error.307 when called on a type other than JSON object;
-    example: `"cannot use erase() with null"`
-    @throw out_of_range.401 when `idx >= size()`; example: `"array index 17
-    is out of range"`
-
-    @complexity Linear in distance between @a idx and the end of the container.
-
-    @liveexample{The example shows the effect of `erase()`.,erase__size_type}
-
-    @sa @ref erase(IteratorType) -- removes the element at a given position
-    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
-    the given range
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
-    from an object at the given key
-
-    @since version 1.0.0
-    */
-    void erase(const size_type idx)
+    /// escape "~"" to "~0" and "/" to "~1"
+    static std::string escape(std::string s)
     {
-        // this erase only works for arrays
-        if (is_array())
-        {
-            if (idx >= size())
-            {
-                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
-            }
-
-            m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
-        }
-        else
-        {
-            JSON_THROW(type_error::create(307, "cannot use erase() with " + type_name()));
-        }
+        replace_substring(s, "~", "~0");
+        replace_substring(s, "/", "~1");
+        return s;
     }
 
-    /// @}
-
-
-    ////////////
-    // lookup //
-    ////////////
-
-    /// @name lookup
-    /// @{
-
-    /*!
-    @brief find an element in a JSON object
-
-    Finds an element in a JSON object with key equivalent to @a key. If the
-    element is not found or the JSON value is not an object, end() is
-    returned.
-
-    @note This method always returns @ref end() when executed on a JSON type
-          that is not an object.
-
-    @param[in] key key value of the element to search for
-
-    @return Iterator to an element with key equivalent to @a key. If no such
-    element is found or the JSON value is not an object, past-the-end (see
-    @ref end()) iterator is returned.
-
-    @complexity Logarithmic in the size of the JSON object.
-
-    @liveexample{The example shows how `find()` is used.,find__key_type}
-
-    @since version 1.0.0
-    */
-    iterator find(typename object_t::key_type key)
+    /// unescape "~1" to tilde and "~0" to slash (order is important!)
+    static void unescape(std::string& s)
     {
-        auto result = end();
-
-        if (is_object())
-        {
-            result.m_it.object_iterator = m_value.object->find(key);
-        }
-
-        return result;
+        replace_substring(s, "~1", "/");
+        replace_substring(s, "~0", "~");
     }
 
     /*!
-    @brief find an element in a JSON object
-    @copydoc find(typename object_t::key_type)
-    */
-    const_iterator find(typename object_t::key_type key) const
-    {
-        auto result = cend();
-
-        if (is_object())
-        {
-            result.m_it.object_iterator = m_value.object->find(key);
-        }
+    @param[in] reference_string  the reference string to the current value
+    @param[in] value             the value to consider
+    @param[in,out] result        the result object to insert values to
 
-        return result;
-    }
+    @note Empty objects or arrays are flattened to `null`.
+    */
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    static void flatten(const std::string& reference_string,
+                        const NLOHMANN_BASIC_JSON_TPL& value,
+                        NLOHMANN_BASIC_JSON_TPL& result);
 
     /*!
-    @brief returns the number of occurrences of a key in a JSON object
-
-    Returns the number of elements with key @a key. If ObjectType is the
-    default `std::map` type, the return value will always be `0` (@a key was
-    not found) or `1` (@a key was found).
+    @param[in] value  flattened JSON
 
-    @note This method always returns `0` when executed on a JSON type that is
-          not an object.
+    @return unflattened JSON
 
-    @param[in] key key value of the element to count
+    @throw parse_error.109 if array index is not a number
+    @throw type_error.314  if value is not an object
+    @throw type_error.315  if object values are not primitive
+    @throw type_error.313  if value cannot be unflattened
+    */
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    static NLOHMANN_BASIC_JSON_TPL
+    unflatten(const NLOHMANN_BASIC_JSON_TPL& value);
 
-    @return Number of elements with key @a key. If the JSON value is not an
-    object, the return value will be `0`.
+    friend bool operator==(json_pointer const& lhs,
+                           json_pointer const& rhs) noexcept;
 
-    @complexity Logarithmic in the size of the JSON object.
+    friend bool operator!=(json_pointer const& lhs,
+                           json_pointer const& rhs) noexcept;
 
-    @liveexample{The example shows how `count()` is used.,count}
+    /// the reference tokens
+    std::vector<std::string> reference_tokens;
+};
 
-    @since version 1.0.0
-    */
-    size_type count(typename object_t::key_type key) const
-    {
-        // return 0 for all nonobject types
-        return is_object() ? m_value.object->count(key) : 0;
-    }
-
-    /// @}
-
-
-    ///////////////
-    // iterators //
-    ///////////////
+/*!
+@brief a class to store JSON values
 
-    /// @name iterators
-    /// @{
+@tparam ObjectType type for JSON objects (`std::map` by default; will be used
+in @ref object_t)
+@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used
+in @ref array_t)
+@tparam StringType type for JSON strings and object keys (`std::string` by
+default; will be used in @ref string_t)
+@tparam BooleanType type for JSON booleans (`bool` by default; will be used
+in @ref boolean_t)
+@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by
+default; will be used in @ref number_integer_t)
+@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c
+`uint64_t` by default; will be used in @ref number_unsigned_t)
+@tparam NumberFloatType type for JSON floating-point numbers (`double` by
+default; will be used in @ref number_float_t)
+@tparam AllocatorType type of the allocator to use (`std::allocator` by
+default)
+@tparam JSONSerializer the serializer to resolve internal calls to `to_json()`
+and `from_json()` (@ref adl_serializer by default)
 
-    /*!
-    @brief returns an iterator to the first element
+@requirement The class satisfies the following concept requirements:
+- Basic
+ - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible):
+   JSON values can be default constructed. The result will be a JSON null
+   value.
+ - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible):
+   A JSON value can be constructed from an rvalue argument.
+ - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible):
+   A JSON value can be copy-constructed from an lvalue expression.
+ - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable):
+   A JSON value van be assigned from an rvalue argument.
+ - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable):
+   A JSON value can be copy-assigned from an lvalue expression.
+ - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible):
+   JSON values can be destructed.
+- Layout
+ - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType):
+   JSON values have
+   [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout):
+   All non-static data members are private and standard layout types, the
+   class has no virtual functions or (virtual) base classes.
+- Library-wide
+ - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable):
+   JSON values can be compared with `==`, see @ref
+   operator==(const_reference,const_reference).
+ - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable):
+   JSON values can be compared with `<`, see @ref
+   operator<(const_reference,const_reference).
+ - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable):
+   Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of
+   other compatible types, using unqualified function call @ref swap().
+ - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer):
+   JSON values can be compared against `std::nullptr_t` objects which are used
+   to model the `null` value.
+- Container
+ - [Container](http://en.cppreference.com/w/cpp/concept/Container):
+   JSON values can be used like STL containers and provide iterator access.
+ - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer);
+   JSON values can be used like STL containers and provide reverse iterator
+   access.
 
-    Returns an iterator to the first element.
+@invariant The member variables @a m_value and @a m_type have the following
+relationship:
+- If `m_type == value_t::object`, then `m_value.object != nullptr`.
+- If `m_type == value_t::array`, then `m_value.array != nullptr`.
+- If `m_type == value_t::string`, then `m_value.string != nullptr`.
+The invariants are checked by member function assert_invariant().
 
-    @image html range-begin-end.svg "Illustration from cppreference.com"
+@internal
+@note ObjectType trick from http://stackoverflow.com/a/9860911
+@endinternal
 
-    @return iterator to the first element
+@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
+Format](http://rfc7159.net/rfc7159)
 
-    @complexity Constant.
+@since version 1.0.0
 
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
+@nosubgrouping
+*/
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+class basic_json
+{
+  private:
+    template<detail::value_t> friend struct detail::external_constructor;
+    friend ::nlohmann::json_pointer;
+    friend ::nlohmann::detail::parser<basic_json>;
+    friend ::nlohmann::detail::serializer<basic_json>;
+    template<typename BasicJsonType>
+    friend class ::nlohmann::detail::iter_impl;
+    template<typename BasicJsonType, typename CharType>
+    friend class ::nlohmann::detail::binary_writer;
+    template<typename BasicJsonType>
+    friend class ::nlohmann::detail::binary_reader;
 
-    @liveexample{The following code shows an example for `begin()`.,begin}
+    /// workaround type for MSVC
+    using basic_json_t = NLOHMANN_BASIC_JSON_TPL;
 
-    @sa @ref cbegin() -- returns a const iterator to the beginning
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref cend() -- returns a const iterator to the end
+    // convenience aliases for types residing in namespace detail;
+    using lexer = ::nlohmann::detail::lexer<basic_json>;
+    using parser = ::nlohmann::detail::parser<basic_json>;
 
-    @since version 1.0.0
-    */
-    iterator begin() noexcept
-    {
-        iterator result(this);
-        result.set_begin();
-        return result;
-    }
+    using primitive_iterator_t = ::nlohmann::detail::primitive_iterator_t;
+    template<typename BasicJsonType>
+    using internal_iterator = ::nlohmann::detail::internal_iterator<BasicJsonType>;
+    template<typename BasicJsonType>
+    using iter_impl = ::nlohmann::detail::iter_impl<BasicJsonType>;
+    template<typename Iterator>
+    using iteration_proxy = ::nlohmann::detail::iteration_proxy<Iterator>;
+    template<typename Base> using json_reverse_iterator = ::nlohmann::detail::json_reverse_iterator<Base>;
 
-    /*!
-    @copydoc basic_json::cbegin()
-    */
-    const_iterator begin() const noexcept
-    {
-        return cbegin();
-    }
+    template<typename CharType>
+    using output_adapter_t = ::nlohmann::detail::output_adapter_t<CharType>;
 
-    /*!
-    @brief returns a const iterator to the first element
+    using binary_reader = ::nlohmann::detail::binary_reader<basic_json>;
+    template<typename CharType> using binary_writer = ::nlohmann::detail::binary_writer<basic_json, CharType>;
 
-    Returns a const iterator to the first element.
+    using serializer = ::nlohmann::detail::serializer<basic_json>;
 
-    @image html range-begin-end.svg "Illustration from cppreference.com"
+  public:
+    using value_t = detail::value_t;
+    /// @copydoc nlohmann::json_pointer
+    using json_pointer = ::nlohmann::json_pointer;
+    template<typename T, typename SFINAE>
+    using json_serializer = JSONSerializer<T, SFINAE>;
+    /// helper type for initializer lists of basic_json values
+    using initializer_list_t = std::initializer_list<detail::json_ref<basic_json>>;
 
-    @return const iterator to the first element
+    ////////////////
+    // exceptions //
+    ////////////////
 
-    @complexity Constant.
+    /// @name exceptions
+    /// Classes to implement user-defined exceptions.
+    /// @{
 
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).begin()`.
+    /// @copydoc detail::exception
+    using exception = detail::exception;
+    /// @copydoc detail::parse_error
+    using parse_error = detail::parse_error;
+    /// @copydoc detail::invalid_iterator
+    using invalid_iterator = detail::invalid_iterator;
+    /// @copydoc detail::type_error
+    using type_error = detail::type_error;
+    /// @copydoc detail::out_of_range
+    using out_of_range = detail::out_of_range;
+    /// @copydoc detail::other_error
+    using other_error = detail::other_error;
 
-    @liveexample{The following code shows an example for `cbegin()`.,cbegin}
+    /// @}
 
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref cend() -- returns a const iterator to the end
 
-    @since version 1.0.0
-    */
-    const_iterator cbegin() const noexcept
-    {
-        const_iterator result(this);
-        result.set_begin();
-        return result;
-    }
+    /////////////////////
+    // container types //
+    /////////////////////
 
-    /*!
-    @brief returns an iterator to one past the last element
+    /// @name container types
+    /// The canonic container types to use @ref basic_json like any other STL
+    /// container.
+    /// @{
 
-    Returns an iterator to one past the last element.
+    /// the type of elements in a basic_json container
+    using value_type = basic_json;
 
-    @image html range-begin-end.svg "Illustration from cppreference.com"
+    /// the type of an element reference
+    using reference = value_type&;
+    /// the type of an element const reference
+    using const_reference = const value_type&;
 
-    @return iterator one past the last element
+    /// a type to represent differences between iterators
+    using difference_type = std::ptrdiff_t;
+    /// a type to represent container sizes
+    using size_type = std::size_t;
 
-    @complexity Constant.
+    /// the allocator type
+    using allocator_type = AllocatorType<basic_json>;
 
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
+    /// the type of an element pointer
+    using pointer = typename std::allocator_traits<allocator_type>::pointer;
+    /// the type of an element const pointer
+    using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer;
 
-    @liveexample{The following code shows an example for `end()`.,end}
+    /// an iterator for a basic_json container
+    using iterator = iter_impl<basic_json>;
+    /// a const iterator for a basic_json container
+    using const_iterator = iter_impl<const basic_json>;
+    /// a reverse iterator for a basic_json container
+    using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>;
+    /// a const reverse iterator for a basic_json container
+    using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>;
 
-    @sa @ref cend() -- returns a const iterator to the end
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref cbegin() -- returns a const iterator to the beginning
+    /// @}
 
-    @since version 1.0.0
-    */
-    iterator end() noexcept
-    {
-        iterator result(this);
-        result.set_end();
-        return result;
-    }
 
     /*!
-    @copydoc basic_json::cend()
+    @brief returns the allocator associated with the container
     */
-    const_iterator end() const noexcept
+    static allocator_type get_allocator()
     {
-        return cend();
+        return allocator_type();
     }
 
     /*!
-    @brief returns a const iterator to one past the last element
+    @brief returns version information on the library
 
-    Returns a const iterator to one past the last element.
+    This function returns a JSON object with information about the library,
+    including the version number and information on the platform and compiler.
 
-    @image html range-begin-end.svg "Illustration from cppreference.com"
+    @return JSON object holding version information
+    key         | description
+    ----------- | ---------------
+    `compiler`  | Information on the used compiler. It is an object with the following keys: `c++` (the used C++ standard), `family` (the compiler family; possible values are `clang`, `icc`, `gcc`, `ilecpp`, `msvc`, `pgcpp`, `sunpro`, and `unknown`), and `version` (the compiler version).
+    `copyright` | The copyright line for the library as string.
+    `name`      | The name of the library as string.
+    `platform`  | The used platform as string. Possible values are `win32`, `linux`, `apple`, `unix`, and `unknown`.
+    `url`       | The URL of the project as string.
+    `version`   | The version of the library. It is an object with the following keys: `major`, `minor`, and `patch` as defined by [Semantic Versioning](http://semver.org), and `string` (the version string).
 
-    @return const iterator one past the last element
+    @liveexample{The following code shows an example output of the `meta()`
+    function.,meta}
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
 
     @complexity Constant.
 
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).end()`.
+    @since 2.1.0
+    */
+    static basic_json meta()
+    {
+        basic_json result;
 
-    @liveexample{The following code shows an example for `cend()`.,cend}
+        result["copyright"] = "(C) 2013-2017 Niels Lohmann";
+        result["name"] = "JSON for Modern C++";
+        result["url"] = "https://github.com/nlohmann/json";
+        result["version"] =
+        {
+            {"string", "3.0.1"}, {"major", 3}, {"minor", 0}, {"patch", 1}
+        };
 
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref cbegin() -- returns a const iterator to the beginning
+#ifdef _WIN32
+        result["platform"] = "win32";
+#elif defined __linux__
+        result["platform"] = "linux";
+#elif defined __APPLE__
+        result["platform"] = "apple";
+#elif defined __unix__
+        result["platform"] = "unix";
+#else
+        result["platform"] = "unknown";
+#endif
 
-    @since version 1.0.0
-    */
-    const_iterator cend() const noexcept
-    {
-        const_iterator result(this);
-        result.set_end();
+#if defined(__ICC) || defined(__INTEL_COMPILER)
+        result["compiler"] = {{"family", "icc"}, {"version", __INTEL_COMPILER}};
+#elif defined(__clang__)
+        result["compiler"] = {{"family", "clang"}, {"version", __clang_version__}};
+#elif defined(__GNUC__) || defined(__GNUG__)
+        result["compiler"] = {{"family", "gcc"}, {"version", std::to_string(__GNUC__) + "." + std::to_string(__GNUC_MINOR__) + "." + std::to_string(__GNUC_PATCHLEVEL__)}};
+#elif defined(__HP_cc) || defined(__HP_aCC)
+        result["compiler"] = "hp"
+#elif defined(__IBMCPP__)
+        result["compiler"] = {{"family", "ilecpp"}, {"version", __IBMCPP__}};
+#elif defined(_MSC_VER)
+        result["compiler"] = {{"family", "msvc"}, {"version", _MSC_VER}};
+#elif defined(__PGI)
+        result["compiler"] = {{"family", "pgcpp"}, {"version", __PGI}};
+#elif defined(__SUNPRO_CC)
+        result["compiler"] = {{"family", "sunpro"}, {"version", __SUNPRO_CC}};
+#else
+        result["compiler"] = {{"family", "unknown"}, {"version", "unknown"}};
+#endif
+
+#ifdef __cplusplus
+        result["compiler"]["c++"] = std::to_string(__cplusplus);
+#else
+        result["compiler"]["c++"] = "unknown";
+#endif
         return result;
     }
 
+
+    ///////////////////////////
+    // JSON value data types //
+    ///////////////////////////
+
+    /// @name JSON value data types
+    /// The data types to store a JSON value. These types are derived from
+    /// the template arguments passed to class @ref basic_json.
+    /// @{
+
+#if defined(JSON_HAS_CPP_14)
+    // Use transparent comparator if possible, combined with perfect forwarding
+    // on find() and count() calls prevents unnecessary string construction.
+    using object_comparator_t = std::less<>;
+#else
+    using object_comparator_t = std::less<StringType>;
+#endif
+
     /*!
-    @brief returns an iterator to the reverse-beginning
+    @brief a type for an object
 
-    Returns an iterator to the reverse-beginning; that is, the last element.
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
+    > An object is an unordered collection of zero or more name/value pairs,
+    > where a name is a string and a value is a string, number, boolean, null,
+    > object, or array.
 
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+    To store objects in C++, a type is defined by the template parameters
+    described below.
 
-    @complexity Constant.
+    @tparam ObjectType  the container to store objects (e.g., `std::map` or
+    `std::unordered_map`)
+    @tparam StringType the type of the keys or names (e.g., `std::string`).
+    The comparison function `std::less<StringType>` is used to order elements
+    inside the container.
+    @tparam AllocatorType the allocator to use for objects (e.g.,
+    `std::allocator`)
 
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `reverse_iterator(end())`.
+    #### Default type
 
-    @liveexample{The following code shows an example for `rbegin()`.,rbegin}
+    With the default values for @a ObjectType (`std::map`), @a StringType
+    (`std::string`), and @a AllocatorType (`std::allocator`), the default
+    value for @a object_t is:
 
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref crend() -- returns a const reverse iterator to the end
+    @code {.cpp}
+    std::map<
+      std::string, // key_type
+      basic_json, // value_type
+      std::less<std::string>, // key_compare
+      std::allocator<std::pair<const std::string, basic_json>> // allocator_type
+    >
+    @endcode
 
-    @since version 1.0.0
-    */
-    reverse_iterator rbegin() noexcept
-    {
-        return reverse_iterator(end());
-    }
+    #### Behavior
 
-    /*!
-    @copydoc basic_json::crbegin()
-    */
-    const_reverse_iterator rbegin() const noexcept
-    {
-        return crbegin();
-    }
+    The choice of @a object_t influences the behavior of the JSON class. With
+    the default type, objects have the following behavior:
 
-    /*!
-    @brief returns an iterator to the reverse-end
+    - When all names are unique, objects will be interoperable in the sense
+      that all software implementations receiving that object will agree on
+      the name-value mappings.
+    - When the names within an object are not unique, later stored name/value
+      pairs overwrite previously stored name/value pairs, leaving the used
+      names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will
+      be treated as equal and both stored as `{"key": 1}`.
+    - Internally, name/value pairs are stored in lexicographical order of the
+      names. Objects will also be serialized (see @ref dump) in this order.
+      For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored
+      and serialized as `{"a": 2, "b": 1}`.
+    - When comparing objects, the order of the name/value pairs is irrelevant.
+      This makes objects interoperable in the sense that they will not be
+      affected by these differences. For instance, `{"b": 1, "a": 2}` and
+      `{"a": 2, "b": 1}` will be treated as equal.
 
-    Returns an iterator to the reverse-end; that is, one before the first
-    element.
+    #### Limits
 
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the maximum depth of nesting.
 
-    @complexity Constant.
+    In this class, the object's limit of nesting is not explicitly constrained.
+    However, a maximum depth of nesting may be introduced by the compiler or
+    runtime environment. A theoretical limit can be queried by calling the
+    @ref max_size function of a JSON object.
 
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `reverse_iterator(begin())`.
+    #### Storage
 
-    @liveexample{The following code shows an example for `rend()`.,rend}
+    Objects are stored as pointers in a @ref basic_json type. That is, for any
+    access to object values, a pointer of type `object_t*` must be
+    dereferenced.
 
-    @sa @ref crend() -- returns a const reverse iterator to the end
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+    @sa @ref array_t -- type for an array value
 
     @since version 1.0.0
-    */
-    reverse_iterator rend() noexcept
-    {
-        return reverse_iterator(begin());
-    }
 
-    /*!
-    @copydoc basic_json::crend()
+    @note The order name/value pairs are added to the object is *not*
+    preserved by the library. Therefore, iterating an object may return
+    name/value pairs in a different order than they were originally stored. In
+    fact, keys will be traversed in alphabetical order as `std::map` with
+    `std::less` is used by default. Please note this behavior conforms to [RFC
+    7159](http://rfc7159.net/rfc7159), because any order implements the
+    specified "unordered" nature of JSON objects.
     */
-    const_reverse_iterator rend() const noexcept
-    {
-        return crend();
-    }
+    using object_t = ObjectType<StringType,
+          basic_json,
+          object_comparator_t,
+          AllocatorType<std::pair<const StringType,
+          basic_json>>>;
 
     /*!
-    @brief returns a const reverse iterator to the last element
-
-    Returns a const iterator to the reverse-beginning; that is, the last
-    element.
-
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+    @brief a type for an array
 
-    @complexity Constant.
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
+    > An array is an ordered sequence of zero or more values.
 
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).rbegin()`.
+    To store objects in C++, a type is defined by the template parameters
+    explained below.
 
-    @liveexample{The following code shows an example for `crbegin()`.,crbegin}
+    @tparam ArrayType  container type to store arrays (e.g., `std::vector` or
+    `std::list`)
+    @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`)
 
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref crend() -- returns a const reverse iterator to the end
+    #### Default type
 
-    @since version 1.0.0
-    */
-    const_reverse_iterator crbegin() const noexcept
-    {
-        return const_reverse_iterator(cend());
-    }
+    With the default values for @a ArrayType (`std::vector`) and @a
+    AllocatorType (`std::allocator`), the default value for @a array_t is:
 
-    /*!
-    @brief returns a const reverse iterator to one before the first
+    @code {.cpp}
+    std::vector<
+      basic_json, // value_type
+      std::allocator<basic_json> // allocator_type
+    >
+    @endcode
 
-    Returns a const reverse iterator to the reverse-end; that is, one before
-    the first element.
+    #### Limits
 
-    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the maximum depth of nesting.
 
-    @complexity Constant.
+    In this class, the array's limit of nesting is not explicitly constrained.
+    However, a maximum depth of nesting may be introduced by the compiler or
+    runtime environment. A theoretical limit can be queried by calling the
+    @ref max_size function of a JSON array.
 
-    @requirement This function helps `basic_json` satisfying the
-    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `const_cast<const basic_json&>(*this).rend()`.
+    #### Storage
 
-    @liveexample{The following code shows an example for `crend()`.,crend}
+    Arrays are stored as pointers in a @ref basic_json type. That is, for any
+    access to array values, a pointer of type `array_t*` must be dereferenced.
 
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+    @sa @ref object_t -- type for an object value
 
     @since version 1.0.0
     */
-    const_reverse_iterator crend() const noexcept
-    {
-        return const_reverse_iterator(cbegin());
-    }
+    using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
 
-  private:
-    // forward declaration
-    template<typename IteratorType> class iteration_proxy;
-
-  public:
     /*!
-    @brief wrapper to access iterator member functions in range-based for
-
-    This function allows to access @ref iterator::key() and @ref
-    iterator::value() during range-based for loops. In these loops, a
-    reference to the JSON values is returned, so there is no access to the
-    underlying iterator.
-
-    @note The name of this function is not yet final and may change in the
-    future.
-    */
-    static iteration_proxy<iterator> iterator_wrapper(reference cont)
-    {
-        return iteration_proxy<iterator>(cont);
-    }
+    @brief a type for a string
 
-    /*!
-    @copydoc iterator_wrapper(reference)
-    */
-    static iteration_proxy<const_iterator> iterator_wrapper(const_reference cont)
-    {
-        return iteration_proxy<const_iterator>(cont);
-    }
+    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
+    > A string is a sequence of zero or more Unicode characters.
 
-    /// @}
+    To store objects in C++, a type is defined by the template parameter
+    described below. Unicode values are split by the JSON class into
+    byte-sized characters during deserialization.
 
+    @tparam StringType  the container to store strings (e.g., `std::string`).
+    Note this container is used for keys/names in objects, see @ref object_t.
 
-    //////////////
-    // capacity //
-    //////////////
+    #### Default type
 
-    /// @name capacity
-    /// @{
+    With the default values for @a StringType (`std::string`), the default
+    value for @a string_t is:
 
-    /*!
-    @brief checks whether the container is empty
+    @code {.cpp}
+    std::string
+    @endcode
 
-    Checks if a JSON value has no elements.
+    #### Encoding
 
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `true`
-            boolean     | `false`
-            string      | `false`
-            number      | `false`
-            object      | result of function `object_t::empty()`
-            array       | result of function `array_t::empty()`
+    Strings are stored in UTF-8 encoding. Therefore, functions like
+    `std::string::size()` or `std::string::length()` return the number of
+    bytes in the string rather than the number of characters or glyphs.
 
-    @note This function does not return whether a string stored as JSON value
-    is empty - it returns whether the JSON container itself is empty which is
-    false in the case of a string.
+    #### String comparison
 
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their `empty()` functions have constant
-    complexity.
+    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    > Software implementations are typically required to test names of object
+    > members for equality. Implementations that transform the textual
+    > representation into sequences of Unicode code units and then perform the
+    > comparison numerically, code unit by code unit, are interoperable in the
+    > sense that implementations will agree in all cases on equality or
+    > inequality of two strings. For example, implementations that compare
+    > strings with escaped characters unconverted may incorrectly find that
+    > `"a\\b"` and `"a\u005Cb"` are not equal.
 
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `begin() == end()`.
+    This implementation is interoperable as it does compare strings code unit
+    by code unit.
 
-    @liveexample{The following code uses `empty()` to check if a JSON
-    object contains any elements.,empty}
+    #### Storage
 
-    @sa @ref size() -- returns the number of elements
+    String values are stored as pointers in a @ref basic_json type. That is,
+    for any access to string values, a pointer of type `string_t*` must be
+    dereferenced.
 
     @since version 1.0.0
     */
-    bool empty() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-            {
-                // null values are empty
-                return true;
-            }
-
-            case value_t::array:
-            {
-                // delegate call to array_t::empty()
-                return m_value.array->empty();
-            }
-
-            case value_t::object:
-            {
-                // delegate call to object_t::empty()
-                return m_value.object->empty();
-            }
-
-            default:
-            {
-                // all other types are nonempty
-                return false;
-            }
-        }
-    }
+    using string_t = StringType;
 
     /*!
-    @brief returns the number of elements
+    @brief a type for a boolean
 
-    Returns the number of elements in a JSON value.
+    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
+    type which differentiates the two literals `true` and `false`.
 
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `0`
-            boolean     | `1`
-            string      | `1`
-            number      | `1`
-            object      | result of function object_t::size()
-            array       | result of function array_t::size()
+    To store objects in C++, a type is defined by the template parameter @a
+    BooleanType which chooses the type to use.
 
-    @note This function does not return the length of a string stored as JSON
-    value - it returns the number of elements in the JSON value which is 1 in
-    the case of a string.
+    #### Default type
 
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their size() functions have constant
-    complexity.
+    With the default values for @a BooleanType (`bool`), the default value for
+    @a boolean_t is:
 
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of `std::distance(begin(), end())`.
+    @code {.cpp}
+    bool
+    @endcode
 
-    @liveexample{The following code calls `size()` on the different value
-    types.,size}
+    #### Storage
 
-    @sa @ref empty() -- checks whether the container is empty
-    @sa @ref max_size() -- returns the maximal number of elements
+    Boolean values are stored directly inside a @ref basic_json type.
 
     @since version 1.0.0
     */
-    size_type size() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::null:
-            {
-                // null values are empty
-                return 0;
-            }
+    using boolean_t = BooleanType;
 
-            case value_t::array:
-            {
-                // delegate call to array_t::size()
-                return m_value.array->size();
-            }
+    /*!
+    @brief a type for a number (integer)
 
-            case value_t::object:
-            {
-                // delegate call to object_t::size()
-                return m_value.object->size();
-            }
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
 
-            default:
-            {
-                // all other types have size 1
-                return 1;
-            }
-        }
-    }
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
 
-    /*!
-    @brief returns the maximum possible number of elements
+    To store integer numbers in C++, a type is defined by the template
+    parameter @a NumberIntegerType which chooses the type to use.
 
-    Returns the maximum number of elements a JSON value is able to hold due to
-    system or library implementation limitations, i.e. `std::distance(begin(),
-    end())` for the JSON value.
+    #### Default type
 
-    @return The return value depends on the different types and is
-            defined as follows:
-            Value type  | return value
-            ----------- | -------------
-            null        | `0` (same as `size()`)
-            boolean     | `1` (same as `size()`)
-            string      | `1` (same as `size()`)
-            number      | `1` (same as `size()`)
-            object      | result of function `object_t::max_size()`
-            array       | result of function `array_t::max_size()`
+    With the default values for @a NumberIntegerType (`int64_t`), the default
+    value for @a number_integer_t is:
 
-    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
-    the Container concept; that is, their `max_size()` functions have constant
-    complexity.
+    @code {.cpp}
+    int64_t
+    @endcode
 
-    @requirement This function helps `basic_json` satisfying the
-    [Container](http://en.cppreference.com/w/cpp/concept/Container)
-    requirements:
-    - The complexity is constant.
-    - Has the semantics of returning `b.size()` where `b` is the largest
-      possible JSON value.
+    #### Default behavior
 
-    @liveexample{The following code calls `max_size()` on the different value
-    types. Note the output is implementation specific.,max_size}
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in integer literals lead to an interpretation as octal
+      number. Internally, the value will be stored as decimal number. For
+      instance, the C++ integer literal `010` will be serialized to `8`.
+      During deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
 
-    @sa @ref size() -- returns the number of elements
+    #### Limits
 
-    @since version 1.0.0
-    */
-    size_type max_size() const noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::array:
-            {
-                // delegate call to array_t::max_size()
-                return m_value.array->max_size();
-            }
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the range and precision of numbers.
 
-            case value_t::object:
-            {
-                // delegate call to object_t::max_size()
-                return m_value.object->max_size();
-            }
-
-            default:
-            {
-                // all other types have max_size() == size()
-                return size();
-            }
-        }
-    }
-
-    /// @}
-
-
-    ///////////////
-    // modifiers //
-    ///////////////
+    When the default type is used, the maximal integer number that can be
+    stored is `9223372036854775807` (INT64_MAX) and the minimal integer number
+    that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers
+    that are out of range will yield over/underflow when used in a
+    constructor. During deserialization, too large or small integer numbers
+    will be automatically be stored as @ref number_unsigned_t or @ref
+    number_float_t.
 
-    /// @name modifiers
-    /// @{
+    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    > Note that when such software is used, numbers that are integers and are
+    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
+    > that implementations will agree exactly on their numeric values.
 
-    /*!
-    @brief clears the contents
+    As this range is a subrange of the exactly supported range [INT64_MIN,
+    INT64_MAX], this class's integer type is interoperable.
 
-    Clears the content of a JSON value and resets it to the default value as
-    if @ref basic_json(value_t) would have been called:
+    #### Storage
 
-    Value type  | initial value
-    ----------- | -------------
-    null        | `null`
-    boolean     | `false`
-    string      | `""`
-    number      | `0`
-    object      | `{}`
-    array       | `[]`
+    Integer number values are stored directly inside a @ref basic_json type.
 
-    @complexity Linear in the size of the JSON value.
+    @sa @ref number_float_t -- type for number values (floating-point)
 
-    @liveexample{The example below shows the effect of `clear()` to different
-    JSON types.,clear}
+    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
 
     @since version 1.0.0
     */
-    void clear() noexcept
-    {
-        switch (m_type)
-        {
-            case value_t::number_integer:
-            {
-                m_value.number_integer = 0;
-                break;
-            }
+    using number_integer_t = NumberIntegerType;
 
-            case value_t::number_unsigned:
-            {
-                m_value.number_unsigned = 0;
-                break;
-            }
+    /*!
+    @brief a type for a number (unsigned)
 
-            case value_t::number_float:
-            {
-                m_value.number_float = 0.0;
-                break;
-            }
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
 
-            case value_t::boolean:
-            {
-                m_value.boolean = false;
-                break;
-            }
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
 
-            case value_t::string:
-            {
-                m_value.string->clear();
-                break;
-            }
+    To store unsigned integer numbers in C++, a type is defined by the
+    template parameter @a NumberUnsignedType which chooses the type to use.
 
-            case value_t::array:
-            {
-                m_value.array->clear();
-                break;
-            }
+    #### Default type
 
-            case value_t::object:
-            {
-                m_value.object->clear();
-                break;
-            }
+    With the default values for @a NumberUnsignedType (`uint64_t`), the
+    default value for @a number_unsigned_t is:
 
-            default:
-            {
-                break;
-            }
-        }
-    }
+    @code {.cpp}
+    uint64_t
+    @endcode
 
-    /*!
-    @brief add an object to an array
+    #### Default behavior
 
-    Appends the given element @a val to the end of the JSON value. If the
-    function is called on a JSON null value, an empty array is created before
-    appending @a val.
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in integer literals lead to an interpretation as octal
+      number. Internally, the value will be stored as decimal number. For
+      instance, the C++ integer literal `010` will be serialized to `8`.
+      During deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
 
-    @param[in] val the value to add to the JSON array
+    #### Limits
 
-    @throw type_error.308 when called on a type other than JSON array or
-    null; example: `"cannot use push_back() with number"`
+    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    > An implementation may set limits on the range and precision of numbers.
 
-    @complexity Amortized constant.
+    When the default type is used, the maximal integer number that can be
+    stored is `18446744073709551615` (UINT64_MAX) and the minimal integer
+    number that can be stored is `0`. Integer numbers that are out of range
+    will yield over/underflow when used in a constructor. During
+    deserialization, too large or small integer numbers will be automatically
+    be stored as @ref number_integer_t or @ref number_float_t.
 
-    @liveexample{The example shows how `push_back()` and `+=` can be used to
-    add elements to a JSON array. Note how the `null` value was silently
-    converted to a JSON array.,push_back}
+    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    > Note that when such software is used, numbers that are integers and are
+    > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
+    > that implementations will agree exactly on their numeric values.
 
-    @since version 1.0.0
-    */
-    void push_back(basic_json&& val)
-    {
-        // push_back only works for null objects or arrays
-        if (not(is_null() or is_array()))
-        {
-            JSON_THROW(type_error::create(308, "cannot use push_back() with " + type_name()));
-        }
+    As this range is a subrange (when considered in conjunction with the
+    number_integer_t type) of the exactly supported range [0, UINT64_MAX],
+    this class's integer type is interoperable.
 
-        // transform null object into an array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value = value_t::array;
-            assert_invariant();
-        }
+    #### Storage
 
-        // add element to array (move semantics)
-        m_value.array->push_back(std::move(val));
-        // invalidate object
-        val.m_type = value_t::null;
-    }
+    Integer number values are stored directly inside a @ref basic_json type.
 
-    /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
+    @sa @ref number_float_t -- type for number values (floating-point)
+    @sa @ref number_integer_t -- type for number values (integer)
+
+    @since version 2.0.0
     */
-    reference operator+=(basic_json&& val)
-    {
-        push_back(std::move(val));
-        return *this;
-    }
+    using number_unsigned_t = NumberUnsignedType;
 
     /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
-    */
-    void push_back(const basic_json& val)
-    {
-        // push_back only works for null objects or arrays
-        if (not(is_null() or is_array()))
-        {
-            JSON_THROW(type_error::create(308, "cannot use push_back() with " + type_name()));
-        }
+    @brief a type for a number (floating-point)
 
-        // transform null object into an array
-        if (is_null())
-        {
-            m_type = value_t::array;
-            m_value = value_t::array;
-            assert_invariant();
-        }
+    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    > The representation of numbers is similar to that used in most
+    > programming languages. A number is represented in base 10 using decimal
+    > digits. It contains an integer component that may be prefixed with an
+    > optional minus sign, which may be followed by a fraction part and/or an
+    > exponent part. Leading zeros are not allowed. (...) Numeric values that
+    > cannot be represented in the grammar below (such as Infinity and NaN)
+    > are not permitted.
 
-        // add element to array
-        m_value.array->push_back(val);
-    }
+    This description includes both integer and floating-point numbers.
+    However, C++ allows more precise storage if it is known whether the number
+    is a signed integer, an unsigned integer or a floating-point number.
+    Therefore, three different types, @ref number_integer_t, @ref
+    number_unsigned_t and @ref number_float_t are used.
 
-    /*!
-    @brief add an object to an array
-    @copydoc push_back(basic_json&&)
-    */
-    reference operator+=(const basic_json& val)
-    {
-        push_back(val);
-        return *this;
-    }
+    To store floating-point numbers in C++, a type is defined by the template
+    parameter @a NumberFloatType which chooses the type to use.
 
-    /*!
-    @brief add an object to an object
+    #### Default type
 
-    Inserts the given element @a val to the JSON object. If the function is
-    called on a JSON null value, an empty object is created before inserting
-    @a val.
+    With the default values for @a NumberFloatType (`double`), the default
+    value for @a number_float_t is:
 
-    @param[in] val the value to add to the JSON object
+    @code {.cpp}
+    double
+    @endcode
 
-    @throw type_error.308 when called on a type other than JSON object or
-    null; example: `"cannot use push_back() with number"`
+    #### Default behavior
 
-    @complexity Logarithmic in the size of the container, O(log(`size()`)).
+    - The restrictions about leading zeros is not enforced in C++. Instead,
+      leading zeros in floating-point literals will be ignored. Internally,
+      the value will be stored as decimal number. For instance, the C++
+      floating-point literal `01.2` will be serialized to `1.2`. During
+      deserialization, leading zeros yield an error.
+    - Not-a-number (NaN) values will be serialized to `null`.
 
-    @liveexample{The example shows how `push_back()` and `+=` can be used to
-    add elements to a JSON object. Note how the `null` value was silently
-    converted to a JSON object.,push_back__object_t__value}
-
-    @since version 1.0.0
-    */
-    void push_back(const typename object_t::value_type& val)
-    {
-        // push_back only works for null objects or objects
-        if (not(is_null() or is_object()))
-        {
-            JSON_THROW(type_error::create(308, "cannot use push_back() with " + type_name()));
-        }
-
-        // transform null object into an object
-        if (is_null())
-        {
-            m_type = value_t::object;
-            m_value = value_t::object;
-            assert_invariant();
-        }
+    #### Limits
 
-        // add element to array
-        m_value.object->insert(val);
-    }
+    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    > This specification allows implementations to set limits on the range and
+    > precision of numbers accepted. Since software that implements IEEE
+    > 754-2008 binary64 (double precision) numbers is generally available and
+    > widely used, good interoperability can be achieved by implementations
+    > that expect no more precision or range than these provide, in the sense
+    > that implementations will approximate JSON numbers within the expected
+    > precision.
 
-    /*!
-    @brief add an object to an object
-    @copydoc push_back(const typename object_t::value_type&)
-    */
-    reference operator+=(const typename object_t::value_type& val)
-    {
-        push_back(val);
-        return *this;
-    }
+    This implementation does exactly follow this approach, as it uses double
+    precision floating-point numbers. Note values smaller than
+    `-1.79769313486232e+308` and values greater than `1.79769313486232e+308`
+    will be stored as NaN internally and be serialized to `null`.
 
-    /*!
-    @brief add an object to an object
+    #### Storage
 
-    This function allows to use `push_back` with an initializer list. In case
+    Floating-point number values are stored directly inside a @ref basic_json
+    type.
 
-    1. the current value is an object,
-    2. the initializer list @a init contains only two elements, and
-    3. the first element of @a init is a string,
+    @sa @ref number_integer_t -- type for number values (integer)
 
-    @a init is converted into an object element and added using
-    @ref push_back(const typename object_t::value_type&). Otherwise, @a init
-    is converted to a JSON value and added using @ref push_back(basic_json&&).
+    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
 
-    @param[in] init  an initializer list
+    @since version 1.0.0
+    */
+    using number_float_t = NumberFloatType;
 
-    @complexity Linear in the size of the initializer list @a init.
+    /// @}
 
-    @note This function is required to resolve an ambiguous overload error,
-          because pairs like `{"key", "value"}` can be both interpreted as
-          `object_t::value_type` or `std::initializer_list<basic_json>`, see
-          https://github.com/nlohmann/json/issues/235 for more information.
+  private:
 
-    @liveexample{The example shows how initializer lists are treated as
-    objects when possible.,push_back__initializer_list}
-    */
-    void push_back(std::initializer_list<basic_json> init)
+    /// helper for exception-safe object creation
+    template<typename T, typename... Args>
+    static T* create(Args&& ... args)
     {
-        if (is_object() and init.size() == 2 and init.begin()->is_string())
-        {
-            const string_t key = *init.begin();
-            push_back(typename object_t::value_type(key, *(init.begin() + 1)));
-        }
-        else
+        AllocatorType<T> alloc;
+        using AllocatorTraits = std::allocator_traits<AllocatorType<T>>;
+
+        auto deleter = [&](T * object)
         {
-            push_back(basic_json(init));
-        }
+            AllocatorTraits::deallocate(alloc, object, 1);
+        };
+        std::unique_ptr<T, decltype(deleter)> object(AllocatorTraits::allocate(alloc, 1), deleter);
+        AllocatorTraits::construct(alloc, object.get(), std::forward<Args>(args)...);
+        assert(object != nullptr);
+        return object.release();
     }
 
-    /*!
-    @brief add an object to an object
-    @copydoc push_back(std::initializer_list<basic_json>)
-    */
-    reference operator+=(std::initializer_list<basic_json> init)
-    {
-        push_back(init);
-        return *this;
-    }
+    ////////////////////////
+    // JSON value storage //
+    ////////////////////////
 
     /*!
-    @brief add an object to an array
-
-    Creates a JSON value from the passed parameters @a args to the end of the
-    JSON value. If the function is called on a JSON null value, an empty array
-    is created before appending the value created from @a args.
-
-    @param[in] args arguments to forward to a constructor of @ref basic_json
-    @tparam Args compatible types to create a @ref basic_json object
+    @brief a JSON value
 
-    @throw type_error.311 when called on a type other than JSON array or
-    null; example: `"cannot use emplace_back() with number"`
+    The actual storage for a JSON value of the @ref basic_json class. This
+    union combines the different storage types for the JSON value types
+    defined in @ref value_t.
 
-    @complexity Amortized constant.
+    JSON type | value_t type    | used type
+    --------- | --------------- | ------------------------
+    object    | object          | pointer to @ref object_t
+    array     | array           | pointer to @ref array_t
+    string    | string          | pointer to @ref string_t
+    boolean   | boolean         | @ref boolean_t
+    number    | number_integer  | @ref number_integer_t
+    number    | number_unsigned | @ref number_unsigned_t
+    number    | number_float    | @ref number_float_t
+    null      | null            | *no value is stored*
 
-    @liveexample{The example shows how `push_back()` can be used to add
-    elements to a JSON array. Note how the `null` value was silently converted
-    to a JSON array.,emplace_back}
+    @note Variable-length types (objects, arrays, and strings) are stored as
+    pointers. The size of the union should not exceed 64 bits if the default
+    value types are used.
 
-    @since version 2.0.8
+    @since version 1.0.0
     */
-    template<class... Args>
-    void emplace_back(Args&& ... args)
+    union json_value
     {
-        // emplace_back only works for null objects or arrays
-        if (not(is_null() or is_array()))
-        {
-            JSON_THROW(type_error::create(311, "cannot use emplace_back() with " + type_name()));
-        }
+        /// object (stored with pointer to save storage)
+        object_t* object;
+        /// array (stored with pointer to save storage)
+        array_t* array;
+        /// string (stored with pointer to save storage)
+        string_t* string;
+        /// boolean
+        boolean_t boolean;
+        /// number (integer)
+        number_integer_t number_integer;
+        /// number (unsigned integer)
+        number_unsigned_t number_unsigned;
+        /// number (floating-point)
+        number_float_t number_float;
 
-        // transform null object into an array
-        if (is_null())
+        /// default constructor (for null values)
+        json_value() = default;
+        /// constructor for booleans
+        json_value(boolean_t v) noexcept : boolean(v) {}
+        /// constructor for numbers (integer)
+        json_value(number_integer_t v) noexcept : number_integer(v) {}
+        /// constructor for numbers (unsigned)
+        json_value(number_unsigned_t v) noexcept : number_unsigned(v) {}
+        /// constructor for numbers (floating-point)
+        json_value(number_float_t v) noexcept : number_float(v) {}
+        /// constructor for empty values of a given type
+        json_value(value_t t)
         {
-            m_type = value_t::array;
-            m_value = value_t::array;
-            assert_invariant();
-        }
+            switch (t)
+            {
+                case value_t::object:
+                {
+                    object = create<object_t>();
+                    break;
+                }
 
-        // add element to array (perfect forwarding)
-        m_value.array->emplace_back(std::forward<Args>(args)...);
-    }
+                case value_t::array:
+                {
+                    array = create<array_t>();
+                    break;
+                }
 
-    /*!
-    @brief add an object to an object if key does not exist
+                case value_t::string:
+                {
+                    string = create<string_t>("");
+                    break;
+                }
 
-    Inserts a new element into a JSON object constructed in-place with the
-    given @a args if there is no element with the key in the container. If the
-    function is called on a JSON null value, an empty object is created before
-    appending the value created from @a args.
+                case value_t::boolean:
+                {
+                    boolean = boolean_t(false);
+                    break;
+                }
 
-    @param[in] args arguments to forward to a constructor of @ref basic_json
-    @tparam Args compatible types to create a @ref basic_json object
+                case value_t::number_integer:
+                {
+                    number_integer = number_integer_t(0);
+                    break;
+                }
 
-    @return a pair consisting of an iterator to the inserted element, or the
-            already-existing element if no insertion happened, and a bool
-            denoting whether the insertion took place.
+                case value_t::number_unsigned:
+                {
+                    number_unsigned = number_unsigned_t(0);
+                    break;
+                }
 
-    @throw type_error.311 when called on a type other than JSON object or
-    null; example: `"cannot use emplace() with number"`
+                case value_t::number_float:
+                {
+                    number_float = number_float_t(0.0);
+                    break;
+                }
 
-    @complexity Logarithmic in the size of the container, O(log(`size()`)).
+                case value_t::null:
+                {
+                    object = nullptr;  // silence warning, see #821
+                    break;
+                }
 
-    @liveexample{The example shows how `emplace()` can be used to add elements
-    to a JSON object. Note how the `null` value was silently converted to a
-    JSON object. Further note how no value is added if there was already one
-    value stored with the same key.,emplace}
+                default:
+                {
+                    object = nullptr;  // silence warning, see #821
+                    if (JSON_UNLIKELY(t == value_t::null))
+                    {
+                        JSON_THROW(other_error::create(500, "961c151d2e87f2686a955a9be24d316f1362bf21 3.0.1")); // LCOV_EXCL_LINE
+                    }
+                    break;
+                }
+            }
+        }
 
-    @since version 2.0.8
-    */
-    template<class... Args>
-    std::pair<iterator, bool> emplace(Args&& ... args)
-    {
-        // emplace only works for null objects or arrays
-        if (not(is_null() or is_object()))
+        /// constructor for strings
+        json_value(const string_t& value)
         {
-            JSON_THROW(type_error::create(311, "cannot use emplace() with " + type_name()));
+            string = create<string_t>(value);
         }
 
-        // transform null object into an object
-        if (is_null())
+        /// constructor for rvalue strings
+        json_value(string_t&& value)
         {
-            m_type = value_t::object;
-            m_value = value_t::object;
-            assert_invariant();
+            string = create<string_t>(std::move(value));
         }
 
-        // add element to array (perfect forwarding)
-        auto res = m_value.object->emplace(std::forward<Args>(args)...);
-        // create result iterator and set iterator to the result of emplace
-        auto it = begin();
-        it.m_it.object_iterator = res.first;
-
-        // return pair of iterator and boolean
-        return {it, res.second};
-    }
+        /// constructor for objects
+        json_value(const object_t& value)
+        {
+            object = create<object_t>(value);
+        }
 
-    /*!
-    @brief inserts element
+        /// constructor for rvalue objects
+        json_value(object_t&& value)
+        {
+            object = create<object_t>(std::move(value));
+        }
 
-    Inserts element @a val before iterator @a pos.
+        /// constructor for arrays
+        json_value(const array_t& value)
+        {
+            array = create<array_t>(value);
+        }
 
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] val element to insert
-    @return iterator pointing to the inserted @a val.
+        /// constructor for rvalue arrays
+        json_value(array_t&& value)
+        {
+            array = create<array_t>(std::move(value));
+        }
 
-    @throw type_error.309 if called on JSON values other than arrays;
-    example: `"cannot use insert() with string"`
-    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
-    example: `"iterator does not fit current value"`
+        void destroy(value_t t)
+        {
+            switch (t)
+            {
+                case value_t::object:
+                {
+                    AllocatorType<object_t> alloc;
+                    std::allocator_traits<decltype(alloc)>::destroy(alloc, object);
+                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, object, 1);
+                    break;
+                }
 
-    @complexity Constant plus linear in the distance between @a pos and end of
-    the container.
+                case value_t::array:
+                {
+                    AllocatorType<array_t> alloc;
+                    std::allocator_traits<decltype(alloc)>::destroy(alloc, array);
+                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, array, 1);
+                    break;
+                }
 
-    @liveexample{The example shows how `insert()` is used.,insert}
+                case value_t::string:
+                {
+                    AllocatorType<string_t> alloc;
+                    std::allocator_traits<decltype(alloc)>::destroy(alloc, string);
+                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, string, 1);
+                    break;
+                }
 
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, const basic_json& val)
-    {
-        // insert only works for arrays
-        if (is_array())
-        {
-            // check if iterator pos fits to this JSON value
-            if (pos.m_object != this)
-            {
-                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+                default:
+                {
+                    break;
+                }
             }
-
-            // insert to array and return iterator
-            iterator result(this);
-            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
-            return result;
         }
-
-        JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
-    }
+    };
 
     /*!
-    @brief inserts element
-    @copydoc insert(const_iterator, const basic_json&)
+    @brief checks the class invariants
+
+    This function asserts the class invariants. It needs to be called at the
+    end of every constructor to make sure that created objects respect the
+    invariant. Furthermore, it has to be called each time the type of a JSON
+    value is changed, because the invariant expresses a relationship between
+    @a m_type and @a m_value.
     */
-    iterator insert(const_iterator pos, basic_json&& val)
+    void assert_invariant() const
     {
-        return insert(pos, val);
+        assert(m_type != value_t::object or m_value.object != nullptr);
+        assert(m_type != value_t::array or m_value.array != nullptr);
+        assert(m_type != value_t::string or m_value.string != nullptr);
     }
 
+  public:
+    //////////////////////////
+    // JSON parser callback //
+    //////////////////////////
+
     /*!
-    @brief inserts elements
+    @brief parser event types
 
-    Inserts @a cnt copies of @a val before iterator @a pos.
+    The parser callback distinguishes the following events:
+    - `object_start`: the parser read `{` and started to process a JSON object
+    - `key`: the parser read a key of a value in an object
+    - `object_end`: the parser read `}` and finished processing a JSON object
+    - `array_start`: the parser read `[` and started to process a JSON array
+    - `array_end`: the parser read `]` and finished processing a JSON array
+    - `value`: the parser finished reading a JSON value
 
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] cnt number of copies of @a val to insert
-    @param[in] val element to insert
-    @return iterator pointing to the first element inserted, or @a pos if
-    `cnt==0`
+    @image html callback_events.png "Example when certain parse events are triggered"
 
-    @throw type_error.309 if called on JSON values other than arrays; example:
-    `"cannot use insert() with string"`
-    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
-    example: `"iterator does not fit current value"`
+    @sa @ref parser_callback_t for more information and examples
+    */
+    using parse_event_t = typename parser::parse_event_t;
 
-    @complexity Linear in @a cnt plus linear in the distance between @a pos
-    and end of the container.
+    /*!
+    @brief per-element parser callback type
 
-    @liveexample{The example shows how `insert()` is used.,insert__count}
+    With a parser callback function, the result of parsing a JSON text can be
+    influenced. When passed to @ref parse, it is called on certain events
+    (passed as @ref parse_event_t via parameter @a event) with a set recursion
+    depth @a depth and context JSON value @a parsed. The return value of the
+    callback function is a boolean indicating whether the element that emitted
+    the callback shall be kept or not.
 
-    @since version 1.0.0
-    */
-    iterator insert(const_iterator pos, size_type cnt, const basic_json& val)
-    {
-        // insert only works for arrays
-        if (is_array())
-        {
-            // check if iterator pos fits to this JSON value
-            if (pos.m_object != this)
-            {
-                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
-            }
+    We distinguish six scenarios (determined by the event type) in which the
+    callback function can be called. The following table describes the values
+    of the parameters @a depth, @a event, and @a parsed.
 
-            // insert to array and return iterator
-            iterator result(this);
-            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
-            return result;
-        }
+    parameter @a event | description | parameter @a depth | parameter @a parsed
+    ------------------ | ----------- | ------------------ | -------------------
+    parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded
+    parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key
+    parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object
+    parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded
+    parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array
+    parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value
 
-        JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
-    }
+    @image html callback_events.png "Example when certain parse events are triggered"
 
-    /*!
-    @brief inserts elements
+    Discarding a value (i.e., returning `false`) has different effects
+    depending on the context in which function was called:
 
-    Inserts elements from range `[first, last)` before iterator @a pos.
+    - Discarded values in structured types are skipped. That is, the parser
+      will behave as if the discarded value was never read.
+    - In case a value outside a structured type is skipped, it is replaced
+      with `null`. This case happens if the top-level element is skipped.
 
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] first begin of the range of elements to insert
-    @param[in] last end of the range of elements to insert
+    @param[in] depth  the depth of the recursion during parsing
 
-    @throw type_error.309 if called on JSON values other than arrays; example:
-    `"cannot use insert() with string"`
-    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
-    example: `"iterator does not fit current value"`
-    @throw invalid_iterator.210 if @a first and @a last do not belong to the
-    same JSON value; example: `"iterators do not fit"`
-    @throw invalid_iterator.211 if @a first or @a last are iterators into
-    container for which insert is called; example: `"passed iterators may not
-    belong to container"`
+    @param[in] event  an event of type parse_event_t indicating the context in
+    the callback function has been called
 
-    @return iterator pointing to the first element inserted, or @a pos if
-    `first==last`
+    @param[in,out] parsed  the current intermediate parse result; note that
+    writing to this value has no effect for parse_event_t::key events
 
-    @complexity Linear in `std::distance(first, last)` plus linear in the
-    distance between @a pos and end of the container.
+    @return Whether the JSON value which called the function during parsing
+    should be kept (`true`) or not (`false`). In the latter case, it is either
+    skipped completely or replaced by an empty discarded object.
 
-    @liveexample{The example shows how `insert()` is used.,insert__range}
+    @sa @ref parse for examples
 
     @since version 1.0.0
     */
-    iterator insert(const_iterator pos, const_iterator first, const_iterator last)
-    {
-        // insert only works for arrays
-        if (not is_array())
-        {
-            JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
-        }
-
-        // check if iterator pos fits to this JSON value
-        if (pos.m_object != this)
-        {
-            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
-        }
+    using parser_callback_t = typename parser::parser_callback_t;
 
-        // check if range iterators belong to the same JSON object
-        if (first.m_object != last.m_object)
-        {
-            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
-        }
 
-        if (first.m_object == this or last.m_object == this)
-        {
-            JSON_THROW(invalid_iterator::create(211, "passed iterators may not belong to container"));
-        }
+    //////////////////
+    // constructors //
+    //////////////////
 
-        // insert to array and return iterator
-        iterator result(this);
-        result.m_it.array_iterator = m_value.array->insert(
-                                         pos.m_it.array_iterator,
-                                         first.m_it.array_iterator,
-                                         last.m_it.array_iterator);
-        return result;
-    }
+    /// @name constructors and destructors
+    /// Constructors of class @ref basic_json, copy/move constructor, copy
+    /// assignment, static functions creating objects, and the destructor.
+    /// @{
 
     /*!
-    @brief inserts elements
+    @brief create an empty value with a given type
 
-    Inserts elements from initializer list @a ilist before iterator @a pos.
+    Create an empty JSON value with a given type. The value will be default
+    initialized with an empty value which depends on the type:
 
-    @param[in] pos iterator before which the content will be inserted; may be
-    the end() iterator
-    @param[in] ilist initializer list to insert the values from
+    Value type  | initial value
+    ----------- | -------------
+    null        | `null`
+    boolean     | `false`
+    string      | `""`
+    number      | `0`
+    object      | `{}`
+    array       | `[]`
 
-    @throw type_error.309 if called on JSON values other than arrays; example:
-    `"cannot use insert() with string"`
-    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
-    example: `"iterator does not fit current value"`
+    @param[in] v  the type of the value to create
 
-    @return iterator pointing to the first element inserted, or @a pos if
-    `ilist` is empty
+    @complexity Constant.
 
-    @complexity Linear in `ilist.size()` plus linear in the distance between
-    @a pos and end of the container.
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
 
-    @liveexample{The example shows how `insert()` is used.,insert__ilist}
+    @liveexample{The following code shows the constructor for different @ref
+    value_t values,basic_json__value_t}
+
+    @sa @ref clear() -- restores the postcondition of this constructor
 
     @since version 1.0.0
     */
-    iterator insert(const_iterator pos, std::initializer_list<basic_json> ilist)
+    basic_json(const value_t v)
+        : m_type(v), m_value(v)
     {
-        // insert only works for arrays
-        if (not is_array())
-        {
-            JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
-        }
-
-        // check if iterator pos fits to this JSON value
-        if (pos.m_object != this)
-        {
-            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
-        }
-
-        // insert to array and return iterator
-        iterator result(this);
-        result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, ilist);
-        return result;
+        assert_invariant();
     }
 
     /*!
-    @brief inserts elements
+    @brief create a null object
 
-    Inserts elements from range `[first, last)`.
+    Create a `null` JSON value. It either takes a null pointer as parameter
+    (explicitly creating `null`) or no parameter (implicitly creating `null`).
+    The passed null pointer itself is not read -- it is only used to choose
+    the right constructor.
 
-    @param[in] first begin of the range of elements to insert
-    @param[in] last end of the range of elements to insert
+    @complexity Constant.
 
-    @throw type_error.309 if called on JSON values other than objects; example:
-    `"cannot use insert() with string"`
-    @throw invalid_iterator.202 if iterator @a first or @a last does does not
-    point to an object; example: `"iterators first and last must point to
-    objects"`
-    @throw invalid_iterator.210 if @a first and @a last do not belong to the
-    same JSON value; example: `"iterators do not fit"`
-
-    @complexity Logarithmic: `O(N*log(size() + N))`, where `N` is the number
-    of elements to insert.
+    @exceptionsafety No-throw guarantee: this constructor never throws
+    exceptions.
 
-    @liveexample{The example shows how `insert()` is used.,insert__range_object}
+    @liveexample{The following code shows the constructor with and without a
+    null pointer parameter.,basic_json__nullptr_t}
 
-    @since version 3.0.0
+    @since version 1.0.0
     */
-    void insert(const_iterator first, const_iterator last)
+    basic_json(std::nullptr_t = nullptr) noexcept
+        : basic_json(value_t::null)
     {
-        // insert only works for objects
-        if (not is_object())
-        {
-            JSON_THROW(type_error::create(309, "cannot use insert() with " + type_name()));
-        }
+        assert_invariant();
+    }
 
-        // check if range iterators belong to the same JSON object
-        if (first.m_object != last.m_object)
-        {
-            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
-        }
+    /*!
+    @brief create a JSON value
 
-        // passed iterators must belong to objects
-        if (not first.m_object->is_object() or not first.m_object->is_object())
-        {
-            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects"));
-        }
+    This is a "catch all" constructor for all compatible JSON types; that is,
+    types for which a `to_json()` method exists. The constructor forwards the
+    parameter @a val to that method (to `json_serializer<U>::to_json` method
+    with `U = uncvref_t<CompatibleType>`, to be exact).
 
-        m_value.object->insert(first.m_it.object_iterator, last.m_it.object_iterator);
-    }
+    Template type @a CompatibleType includes, but is not limited to, the
+    following types:
+    - **arrays**: @ref array_t and all kinds of compatible containers such as
+      `std::vector`, `std::deque`, `std::list`, `std::forward_list`,
+      `std::array`, `std::valarray`, `std::set`, `std::unordered_set`,
+      `std::multiset`, and `std::unordered_multiset` with a `value_type` from
+      which a @ref basic_json value can be constructed.
+    - **objects**: @ref object_t and all kinds of compatible associative
+      containers such as `std::map`, `std::unordered_map`, `std::multimap`,
+      and `std::unordered_multimap` with a `key_type` compatible to
+      @ref string_t and a `value_type` from which a @ref basic_json value can
+      be constructed.
+    - **strings**: @ref string_t, string literals, and all compatible string
+      containers can be used.
+    - **numbers**: @ref number_integer_t, @ref number_unsigned_t,
+      @ref number_float_t, and all convertible number types such as `int`,
+      `size_t`, `int64_t`, `float` or `double` can be used.
+    - **boolean**: @ref boolean_t / `bool` can be used.
 
-    /*!
-    @brief exchanges the values
+    See the examples below.
 
-    Exchanges the contents of the JSON value with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
+    @tparam CompatibleType a type such that:
+    - @a CompatibleType is not derived from `std::istream`,
+    - @a CompatibleType is not @ref basic_json (to avoid hijacking copy/move
+         constructors),
+    - @a CompatibleType is not a @ref basic_json nested type (e.g.,
+         @ref json_pointer, @ref iterator, etc ...)
+    - @ref @ref json_serializer<U> has a
+         `to_json(basic_json_t&, CompatibleType&&)` method
 
-    @param[in,out] other JSON value to exchange the contents with
+    @tparam U = `uncvref_t<CompatibleType>`
 
-    @complexity Constant.
+    @param[in] val the value to be forwarded to the respective constructor
 
-    @liveexample{The example below shows how JSON values can be swapped with
-    `swap()`.,swap__reference}
+    @complexity Usually linear in the size of the passed @a val, also
+                depending on the implementation of the called `to_json()`
+                method.
 
-    @since version 1.0.0
+    @exceptionsafety Depends on the called constructor. For types directly
+    supported by the library (i.e., all types for which no `to_json()` function
+    was provided), strong guarantee holds: if an exception is thrown, there are
+    no changes to any JSON value.
+
+    @liveexample{The following code shows the constructor with several
+    compatible types.,basic_json__CompatibleType}
+
+    @since version 2.1.0
     */
-    void swap(reference other) noexcept (
-        std::is_nothrow_move_constructible<value_t>::value and
-        std::is_nothrow_move_assignable<value_t>::value and
-        std::is_nothrow_move_constructible<json_value>::value and
-        std::is_nothrow_move_assignable<json_value>::value
-    )
+    template<typename CompatibleType, typename U = detail::uncvref_t<CompatibleType>,
+             detail::enable_if_t<not std::is_base_of<std::istream, U>::value and
+                                 not std::is_same<U, basic_json_t>::value and
+                                 not detail::is_basic_json_nested_type<
+                                     basic_json_t, U>::value and
+                                 detail::has_to_json<basic_json, U>::value,
+                                 int> = 0>
+    basic_json(CompatibleType && val) noexcept(noexcept(JSONSerializer<U>::to_json(
+                std::declval<basic_json_t&>(), std::forward<CompatibleType>(val))))
     {
-        std::swap(m_type, other.m_type);
-        std::swap(m_value, other.m_value);
+        JSONSerializer<U>::to_json(*this, std::forward<CompatibleType>(val));
         assert_invariant();
     }
 
     /*!
-    @brief exchanges the values
+    @brief create a container (array or object) from an initializer list
 
-    Exchanges the contents of a JSON array with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
+    Creates a JSON value of type array or object from the passed initializer
+    list @a init. In case @a type_deduction is `true` (default), the type of
+    the JSON value to be created is deducted from the initializer list @a init
+    according to the following rules:
 
-    @param[in,out] other array to exchange the contents with
+    1. If the list is empty, an empty JSON object value `{}` is created.
+    2. If the list consists of pairs whose first element is a string, a JSON
+       object value is created where the first elements of the pairs are
+       treated as keys and the second elements are as values.
+    3. In all other cases, an array is created.
 
-    @throw type_error.310 when JSON value is not an array; example: `"cannot
-    use swap() with string"`
+    The rules aim to create the best fit between a C++ initializer list and
+    JSON values. The rationale is as follows:
 
-    @complexity Constant.
+    1. The empty initializer list is written as `{}` which is exactly an empty
+       JSON object.
+    2. C++ has no way of describing mapped types other than to list a list of
+       pairs. As JSON requires that keys must be of type string, rule 2 is the
+       weakest constraint one can pose on initializer lists to interpret them
+       as an object.
+    3. In all other cases, the initializer list could not be interpreted as
+       JSON object type, so interpreting it as JSON array type is safe.
 
-    @liveexample{The example below shows how arrays can be swapped with
-    `swap()`.,swap__array_t}
+    With the rules described above, the following JSON values cannot be
+    expressed by an initializer list:
 
-    @since version 1.0.0
-    */
-    void swap(array_t& other)
-    {
-        // swap only works for arrays
-        if (is_array())
-        {
-            std::swap(*(m_value.array), other);
-        }
-        else
-        {
-            JSON_THROW(type_error::create(310, "cannot use swap() with " + type_name()));
-        }
-    }
+    - the empty array (`[]`): use @ref array(initializer_list_t)
+      with an empty initializer list in this case
+    - arrays whose elements satisfy rule 2: use @ref
+      array(initializer_list_t) with the same initializer list
+      in this case
 
-    /*!
-    @brief exchanges the values
+    @note When used without parentheses around an empty initializer list, @ref
+    basic_json() is called instead of this function, yielding the JSON null
+    value.
 
-    Exchanges the contents of a JSON object with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
+    @param[in] init  initializer list with JSON values
 
-    @param[in,out] other object to exchange the contents with
+    @param[in] type_deduction internal parameter; when set to `true`, the type
+    of the JSON value is deducted from the initializer list @a init; when set
+    to `false`, the type provided via @a manual_type is forced. This mode is
+    used by the functions @ref array(initializer_list_t) and
+    @ref object(initializer_list_t).
 
-    @throw type_error.310 when JSON value is not an object; example:
-    `"cannot use swap() with string"`
+    @param[in] manual_type internal parameter; when @a type_deduction is set
+    to `false`, the created JSON value will use the provided type (only @ref
+    value_t::array and @ref value_t::object are valid); when @a type_deduction
+    is set to `true`, this parameter has no effect
 
-    @complexity Constant.
+    @throw type_error.301 if @a type_deduction is `false`, @a manual_type is
+    `value_t::object`, but @a init contains an element which is not a pair
+    whose first element is a string. In this case, the constructor could not
+    create an object. If @a type_deduction would have be `true`, an array
+    would have been created. See @ref object(initializer_list_t)
+    for an example.
 
-    @liveexample{The example below shows how objects can be swapped with
-    `swap()`.,swap__object_t}
+    @complexity Linear in the size of the initializer list @a init.
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
+
+    @liveexample{The example below shows how JSON values are created from
+    initializer lists.,basic_json__list_init_t}
+
+    @sa @ref array(initializer_list_t) -- create a JSON array
+    value from an initializer list
+    @sa @ref object(initializer_list_t) -- create a JSON object
+    value from an initializer list
 
     @since version 1.0.0
     */
-    void swap(object_t& other)
+    basic_json(initializer_list_t init,
+               bool type_deduction = true,
+               value_t manual_type = value_t::array)
     {
-        // swap only works for objects
-        if (is_object())
+        // check if each element is an array with two elements whose first
+        // element is a string
+        bool is_an_object = std::all_of(init.begin(), init.end(),
+                                        [](const detail::json_ref<basic_json>& element_ref)
         {
-            std::swap(*(m_value.object), other);
+            return (element_ref->is_array() and element_ref->size() == 2 and (*element_ref)[0].is_string());
+        });
+
+        // adjust type if type deduction is not wanted
+        if (not type_deduction)
+        {
+            // if array is wanted, do not create an object though possible
+            if (manual_type == value_t::array)
+            {
+                is_an_object = false;
+            }
+
+            // if object is wanted but impossible, throw an exception
+            if (JSON_UNLIKELY(manual_type == value_t::object and not is_an_object))
+            {
+                JSON_THROW(type_error::create(301, "cannot create object from initializer list"));
+            }
+        }
+
+        if (is_an_object)
+        {
+            // the initializer list is a list of pairs -> create object
+            m_type = value_t::object;
+            m_value = value_t::object;
+
+            std::for_each(init.begin(), init.end(), [this](const detail::json_ref<basic_json>& element_ref)
+            {
+                auto element = element_ref.moved_or_copied();
+                m_value.object->emplace(
+                    std::move(*((*element.m_value.array)[0].m_value.string)),
+                    std::move((*element.m_value.array)[1]));
+            });
         }
         else
         {
-            JSON_THROW(type_error::create(310, "cannot use swap() with " + type_name()));
+            // the initializer list describes an array -> create array
+            m_type = value_t::array;
+            m_value.array = create<array_t>(init.begin(), init.end());
         }
+
+        assert_invariant();
     }
 
     /*!
-    @brief exchanges the values
+    @brief explicitly create an array from an initializer list
 
-    Exchanges the contents of a JSON string with those of @a other. Does not
-    invoke any move, copy, or swap operations on individual elements. All
-    iterators and references remain valid. The past-the-end iterator is
-    invalidated.
+    Creates a JSON array value from a given initializer list. That is, given a
+    list of values `a, b, c`, creates the JSON value `[a, b, c]`. If the
+    initializer list is empty, the empty array `[]` is created.
 
-    @param[in,out] other string to exchange the contents with
+    @note This function is only needed to express two edge cases that cannot
+    be realized with the initializer list constructor (@ref
+    basic_json(initializer_list_t, bool, value_t)). These cases
+    are:
+    1. creating an array whose elements are all pairs whose first element is a
+    string -- in this case, the initializer list constructor would create an
+    object, taking the first elements as keys
+    2. creating an empty array -- passing the empty initializer list to the
+    initializer list constructor yields an empty object
 
-    @throw type_error.310 when JSON value is not a string; example: `"cannot
-    use swap() with boolean"`
+    @param[in] init  initializer list with JSON values to create an array from
+    (optional)
 
-    @complexity Constant.
+    @return JSON array value
 
-    @liveexample{The example below shows how strings can be swapped with
-    `swap()`.,swap__string_t}
+    @complexity Linear in the size of @a init.
 
-    @since version 1.0.0
-    */
-    void swap(string_t& other)
-    {
-        // swap only works for strings
-        if (is_string())
-        {
-            std::swap(*(m_value.string), other);
-        }
-        else
-        {
-            JSON_THROW(type_error::create(310, "cannot use swap() with " + type_name()));
-        }
-    }
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
 
-    /// @}
+    @liveexample{The following code shows an example for the `array`
+    function.,array}
 
-  public:
-    //////////////////////////////////////////
-    // lexicographical comparison operators //
-    //////////////////////////////////////////
+    @sa @ref basic_json(initializer_list_t, bool, value_t) --
+    create a JSON value from an initializer list
+    @sa @ref object(initializer_list_t) -- create a JSON object
+    value from an initializer list
 
-    /// @name lexicographical comparison operators
-    /// @{
+    @since version 1.0.0
+    */
+    static basic_json array(initializer_list_t init = {})
+    {
+        return basic_json(init, false, value_t::array);
+    }
 
     /*!
-    @brief comparison: equal
+    @brief explicitly create an object from an initializer list
 
-    Compares two JSON values for equality according to the following rules:
-    - Two JSON values are equal if (1) they are from the same type and (2)
-      their stored values are the same according to their respective
-      `operator==`.
-    - Integer and floating-point numbers are automatically converted before
-      comparison. Floating-point numbers are compared indirectly: two
-      floating-point numbers `f1` and `f2` are considered equal if neither
-      `f1 > f2` nor `f2 > f1` holds. Note than two NaN values are always
-      treated as unequal.
-    - Two JSON null values are equal.
+    Creates a JSON object value from a given initializer list. The initializer
+    lists elements must be pairs, and their first elements must be strings. If
+    the initializer list is empty, the empty object `{}` is created.
 
-    @note NaN values never compare equal to themselves or to other NaN values.
+    @note This function is only added for symmetry reasons. In contrast to the
+    related function @ref array(initializer_list_t), there are
+    no cases which can only be expressed by this function. That is, any
+    initializer list @a init can also be passed to the initializer list
+    constructor @ref basic_json(initializer_list_t, bool, value_t).
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether the values @a lhs and @a rhs are equal
+    @param[in] init  initializer list to create an object from (optional)
 
-    @complexity Linear.
+    @return JSON object value
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__equal}
+    @throw type_error.301 if @a init is not a list of pairs whose first
+    elements are strings. In this case, no object can be created. When such a
+    value is passed to @ref basic_json(initializer_list_t, bool, value_t),
+    an array would have been created from the passed initializer list @a init.
+    See example below.
 
-    @since version 1.0.0
-    */
-    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
-    {
-        const auto lhs_type = lhs.type();
-        const auto rhs_type = rhs.type();
+    @complexity Linear in the size of @a init.
 
-        if (lhs_type == rhs_type)
-        {
-            switch (lhs_type)
-            {
-                case value_t::array:
-                {
-                    return *lhs.m_value.array == *rhs.m_value.array;
-                }
-                case value_t::object:
-                {
-                    return *lhs.m_value.object == *rhs.m_value.object;
-                }
-                case value_t::null:
-                {
-                    return true;
-                }
-                case value_t::string:
-                {
-                    return *lhs.m_value.string == *rhs.m_value.string;
-                }
-                case value_t::boolean:
-                {
-                    return lhs.m_value.boolean == rhs.m_value.boolean;
-                }
-                case value_t::number_integer:
-                {
-                    return lhs.m_value.number_integer == rhs.m_value.number_integer;
-                }
-                case value_t::number_unsigned:
-                {
-                    return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned;
-                }
-                case value_t::number_float:
-                {
-                    return lhs.m_value.number_float == rhs.m_value.number_float;
-                }
-                default:
-                {
-                    return false;
-                }
-            }
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
-        {
-            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
-        {
-            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer;
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned);
-        }
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
 
-        return false;
-    }
+    @liveexample{The following code shows an example for the `object`
+    function.,object}
 
-    /*!
-    @brief comparison: equal
-    @copydoc operator==(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator==(const_reference lhs, const ScalarType rhs) noexcept
-    {
-        return (lhs == basic_json(rhs));
-    }
+    @sa @ref basic_json(initializer_list_t, bool, value_t) --
+    create a JSON value from an initializer list
+    @sa @ref array(initializer_list_t) -- create a JSON array
+    value from an initializer list
 
-    /*!
-    @brief comparison: equal
-    @copydoc operator==(const_reference, const_reference)
+    @since version 1.0.0
     */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator==(const ScalarType lhs, const_reference rhs) noexcept
+    static basic_json object(initializer_list_t init = {})
     {
-        return (basic_json(lhs) == rhs);
+        return basic_json(init, false, value_t::object);
     }
 
     /*!
-    @brief comparison: not equal
+    @brief construct an array with count copies of given value
 
-    Compares two JSON values for inequality by calculating `not (lhs == rhs)`.
+    Constructs a JSON array value by creating @a cnt copies of a passed value.
+    In case @a cnt is `0`, an empty array is created.
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether the values @a lhs and @a rhs are not equal
+    @param[in] cnt  the number of JSON copies of @a val to create
+    @param[in] val  the JSON value to copy
 
-    @complexity Linear.
+    @post `std::distance(begin(),end()) == cnt` holds.
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__notequal}
+    @complexity Linear in @a cnt.
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
+
+    @liveexample{The following code shows examples for the @ref
+    basic_json(size_type\, const basic_json&)
+    constructor.,basic_json__size_type_basic_json}
 
     @since version 1.0.0
     */
-    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
+    basic_json(size_type cnt, const basic_json& val)
+        : m_type(value_t::array)
     {
-        return not (lhs == rhs);
+        m_value.array = create<array_t>(cnt, val);
+        assert_invariant();
     }
 
     /*!
-    @brief comparison: not equal
-    @copydoc operator!=(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator!=(const_reference lhs, const ScalarType rhs) noexcept
-    {
-        return (lhs != basic_json(rhs));
-    }
+    @brief construct a JSON container given an iterator range
 
-    /*!
-    @brief comparison: not equal
-    @copydoc operator!=(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator!=(const ScalarType lhs, const_reference rhs) noexcept
-    {
-        return (basic_json(lhs) != rhs);
-    }
+    Constructs the JSON value with the contents of the range `[first, last)`.
+    The semantics depends on the different types a JSON value can have:
+    - In case of a null type, invalid_iterator.206 is thrown.
+    - In case of other primitive types (number, boolean, or string), @a first
+      must be `begin()` and @a last must be `end()`. In this case, the value is
+      copied. Otherwise, invalid_iterator.204 is thrown.
+    - In case of structured types (array, object), the constructor behaves as
+      similar versions for `std::vector` or `std::map`; that is, a JSON array
+      or object is constructed from the values in the range.
 
-    /*!
-    @brief comparison: less than
+    @tparam InputIT an input iterator type (@ref iterator or @ref
+    const_iterator)
 
-    Compares whether one JSON value @a lhs is less than another JSON value @a
-    rhs according to the following rules:
-    - If @a lhs and @a rhs have the same type, the values are compared using
-      the default `<` operator.
-    - Integer and floating-point numbers are automatically converted before
-      comparison
-    - In case @a lhs and @a rhs have different types, the values are ignored
-      and the order of the types is considered, see
-      @ref operator<(const value_t, const value_t).
+    @param[in] first begin of the range to copy from (included)
+    @param[in] last end of the range to copy from (excluded)
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is less than @a rhs
+    @pre Iterators @a first and @a last must be initialized. **This
+         precondition is enforced with an assertion (see warning).** If
+         assertions are switched off, a violation of this precondition yields
+         undefined behavior.
 
-    @complexity Linear.
+    @pre Range `[first, last)` is valid. Usually, this precondition cannot be
+         checked efficiently. Only certain edge cases are detected; see the
+         description of the exceptions below. A violation of this precondition
+         yields undefined behavior.
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__less}
+    @warning A precondition is enforced with a runtime assertion that will
+             result in calling `std::abort` if this precondition is not met.
+             Assertions can be disabled by defining `NDEBUG` at compile time.
+             See http://en.cppreference.com/w/cpp/error/assert for more
+             information.
+
+    @throw invalid_iterator.201 if iterators @a first and @a last are not
+    compatible (i.e., do not belong to the same JSON value). In this case,
+    the range `[first, last)` is undefined.
+    @throw invalid_iterator.204 if iterators @a first and @a last belong to a
+    primitive type (number, boolean, or string), but @a first does not point
+    to the first element any more. In this case, the range `[first, last)` is
+    undefined. See example code below.
+    @throw invalid_iterator.206 if iterators @a first and @a last belong to a
+    null value. In this case, the range `[first, last)` is undefined.
+
+    @complexity Linear in distance between @a first and @a last.
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
+
+    @liveexample{The example below shows several ways to create JSON values by
+    specifying a subrange with iterators.,basic_json__InputIt_InputIt}
 
     @since version 1.0.0
     */
-    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
+    template<class InputIT, typename std::enable_if<
+                 std::is_same<InputIT, typename basic_json_t::iterator>::value or
+                 std::is_same<InputIT, typename basic_json_t::const_iterator>::value, int>::type = 0>
+    basic_json(InputIT first, InputIT last)
     {
-        const auto lhs_type = lhs.type();
-        const auto rhs_type = rhs.type();
+        assert(first.m_object != nullptr);
+        assert(last.m_object != nullptr);
 
-        if (lhs_type == rhs_type)
+        // make sure iterator fits the current value
+        if (JSON_UNLIKELY(first.m_object != last.m_object))
         {
-            switch (lhs_type)
+            JSON_THROW(invalid_iterator::create(201, "iterators are not compatible"));
+        }
+
+        // copy type from first iterator
+        m_type = first.m_object->m_type;
+
+        // check if iterator range is complete for primitive values
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
             {
-                case value_t::array:
+                if (JSON_UNLIKELY(not first.m_it.primitive_iterator.is_begin()
+                                  or not last.m_it.primitive_iterator.is_end()))
                 {
-                    return *lhs.m_value.array < *rhs.m_value.array;
-                }
-                case value_t::object:
-                {
-                    return *lhs.m_value.object < *rhs.m_value.object;
-                }
-                case value_t::null:
-                {
-                    return false;
-                }
-                case value_t::string:
-                {
-                    return *lhs.m_value.string < *rhs.m_value.string;
-                }
-                case value_t::boolean:
-                {
-                    return lhs.m_value.boolean < rhs.m_value.boolean;
-                }
-                case value_t::number_integer:
-                {
-                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
-                }
-                case value_t::number_unsigned:
-                {
-                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
-                }
-                case value_t::number_float:
-                {
-                    return lhs.m_value.number_float < rhs.m_value.number_float;
-                }
-                default:
-                {
-                    return false;
+                    JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
                 }
+                break;
             }
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
-        {
-            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
-        {
-            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
-        }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
-        {
-            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
-        }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
-        {
-            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
+
+            default:
+                break;
         }
 
-        // We only reach this line if we cannot compare values. In that case,
-        // we compare types. Note we have to call the operator explicitly,
-        // because MSVC has problems otherwise.
-        return operator<(lhs_type, rhs_type);
-    }
+        switch (m_type)
+        {
+            case value_t::number_integer:
+            {
+                m_value.number_integer = first.m_object->m_value.number_integer;
+                break;
+            }
 
-    /*!
-    @brief comparison: less than
-    @copydoc operator<(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator<(const_reference lhs, const ScalarType rhs) noexcept
-    {
-        return (lhs < basic_json(rhs));
-    }
+            case value_t::number_unsigned:
+            {
+                m_value.number_unsigned = first.m_object->m_value.number_unsigned;
+                break;
+            }
 
-    /*!
-    @brief comparison: less than
-    @copydoc operator<(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator<(const ScalarType lhs, const_reference rhs) noexcept
-    {
-        return (basic_json(lhs) < rhs);
-    }
+            case value_t::number_float:
+            {
+                m_value.number_float = first.m_object->m_value.number_float;
+                break;
+            }
 
-    /*!
-    @brief comparison: less than or equal
+            case value_t::boolean:
+            {
+                m_value.boolean = first.m_object->m_value.boolean;
+                break;
+            }
 
-    Compares whether one JSON value @a lhs is less than or equal to another
-    JSON value by calculating `not (rhs < lhs)`.
+            case value_t::string:
+            {
+                m_value = *first.m_object->m_value.string;
+                break;
+            }
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is less than or equal to @a rhs
+            case value_t::object:
+            {
+                m_value.object = create<object_t>(first.m_it.object_iterator,
+                                                  last.m_it.object_iterator);
+                break;
+            }
 
-    @complexity Linear.
+            case value_t::array:
+            {
+                m_value.array = create<array_t>(first.m_it.array_iterator,
+                                                last.m_it.array_iterator);
+                break;
+            }
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__greater}
+            default:
+                JSON_THROW(invalid_iterator::create(206, "cannot construct with iterators from " +
+                                                    std::string(first.m_object->type_name())));
+        }
 
-    @since version 1.0.0
-    */
-    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (rhs < lhs);
+        assert_invariant();
     }
 
-    /*!
-    @brief comparison: less than or equal
-    @copydoc operator<=(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator<=(const_reference lhs, const ScalarType rhs) noexcept
-    {
-        return (lhs <= basic_json(rhs));
-    }
 
-    /*!
-    @brief comparison: less than or equal
-    @copydoc operator<=(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator<=(const ScalarType lhs, const_reference rhs) noexcept
-    {
-        return (basic_json(lhs) <= rhs);
-    }
+    ///////////////////////////////////////
+    // other constructors and destructor //
+    ///////////////////////////////////////
+
+    /// @private
+    basic_json(const detail::json_ref<basic_json>& ref)
+        : basic_json(ref.moved_or_copied())
+    {}
 
     /*!
-    @brief comparison: greater than
+    @brief copy constructor
 
-    Compares whether one JSON value @a lhs is greater than another
-    JSON value by calculating `not (lhs <= rhs)`.
+    Creates a copy of a given JSON value.
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is greater than to @a rhs
+    @param[in] other  the JSON value to copy
 
-    @complexity Linear.
+    @post `*this == other`
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__lessequal}
+    @complexity Linear in the size of @a other.
 
-    @since version 1.0.0
-    */
-    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs <= rhs);
-    }
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
 
-    /*!
-    @brief comparison: greater than
-    @copydoc operator>(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator>(const_reference lhs, const ScalarType rhs) noexcept
-    {
-        return (lhs > basic_json(rhs));
-    }
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
+    - As postcondition, it holds: `other == basic_json(other)`.
 
-    /*!
-    @brief comparison: greater than
-    @copydoc operator>(const_reference, const_reference)
+    @liveexample{The following code shows an example for the copy
+    constructor.,basic_json__basic_json}
+
+    @since version 1.0.0
     */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator>(const ScalarType lhs, const_reference rhs) noexcept
+    basic_json(const basic_json& other)
+        : m_type(other.m_type)
     {
-        return (basic_json(lhs) > rhs);
-    }
+        // check of passed value is valid
+        other.assert_invariant();
 
-    /*!
-    @brief comparison: greater than or equal
+        switch (m_type)
+        {
+            case value_t::object:
+            {
+                m_value = *other.m_value.object;
+                break;
+            }
 
-    Compares whether one JSON value @a lhs is greater than or equal to another
-    JSON value by calculating `not (lhs < rhs)`.
+            case value_t::array:
+            {
+                m_value = *other.m_value.array;
+                break;
+            }
 
-    @param[in] lhs  first JSON value to consider
-    @param[in] rhs  second JSON value to consider
-    @return whether @a lhs is greater than or equal to @a rhs
+            case value_t::string:
+            {
+                m_value = *other.m_value.string;
+                break;
+            }
 
-    @complexity Linear.
+            case value_t::boolean:
+            {
+                m_value = other.m_value.boolean;
+                break;
+            }
 
-    @liveexample{The example demonstrates comparing several JSON
-    types.,operator__greaterequal}
+            case value_t::number_integer:
+            {
+                m_value = other.m_value.number_integer;
+                break;
+            }
 
-    @since version 1.0.0
-    */
-    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
-    {
-        return not (lhs < rhs);
-    }
+            case value_t::number_unsigned:
+            {
+                m_value = other.m_value.number_unsigned;
+                break;
+            }
 
-    /*!
-    @brief comparison: greater than or equal
-    @copydoc operator>=(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator>=(const_reference lhs, const ScalarType rhs) noexcept
-    {
-        return (lhs >= basic_json(rhs));
+            case value_t::number_float:
+            {
+                m_value = other.m_value.number_float;
+                break;
+            }
+
+            default:
+                break;
+        }
+
+        assert_invariant();
     }
 
     /*!
-    @brief comparison: greater than or equal
-    @copydoc operator>=(const_reference, const_reference)
-    */
-    template<typename ScalarType, typename std::enable_if<
-                 std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator>=(const ScalarType lhs, const_reference rhs) noexcept
-    {
-        return (basic_json(lhs) >= rhs);
-    }
+    @brief move constructor
 
-    /// @}
+    Move constructor. Constructs a JSON value with the contents of the given
+    value @a other using move semantics. It "steals" the resources from @a
+    other and leaves it as JSON null value.
 
+    @param[in,out] other  value to move to this object
 
-    ///////////////////
-    // serialization //
-    ///////////////////
+    @post `*this` has the same value as @a other before the call.
+    @post @a other is a JSON null value.
 
-    /// @name serialization
-    /// @{
+    @complexity Constant.
 
-  private:
-    /*!
-    @brief wrapper around the serialization functions
-    */
-    class serializer
-    {
-      private:
-        serializer(const serializer&) = delete;
-        serializer& operator=(const serializer&) = delete;
+    @exceptionsafety No-throw guarantee: this constructor never throws
+    exceptions.
 
-      public:
-        /*!
-        @param[in] s  output stream to serialize to
-        */
-        serializer(std::ostream& s)
-            : o(s), loc(std::localeconv()),
-              thousands_sep(!loc->thousands_sep ? '\0' : loc->thousands_sep[0]),
-              decimal_point(!loc->decimal_point ? '\0' : loc->decimal_point[0])
-        {}
+    @requirement This function helps `basic_json` satisfying the
+    [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible)
+    requirements.
 
-        /*!
-        @brief internal implementation of the serialization function
+    @liveexample{The code below shows the move constructor explicitly called
+    via std::move.,basic_json__moveconstructor}
 
-        This function is called by the public member function dump and
-        organizes the serialization internally. The indentation level is
-        propagated as additional parameter. In case of arrays and objects, the
-        function is called recursively.
+    @since version 1.0.0
+    */
+    basic_json(basic_json&& other) noexcept
+        : m_type(std::move(other.m_type)),
+          m_value(std::move(other.m_value))
+    {
+        // check that passed value is valid
+        other.assert_invariant();
 
-        - strings and object keys are escaped using `escape_string()`
-        - integer numbers are converted implicitly via `operator<<`
-        - floating-point numbers are converted to a string using `"%g"` format
+        // invalidate payload
+        other.m_type = value_t::null;
+        other.m_value = {};
 
-        @param[in] val             value to serialize
-        @param[in] pretty_print    whether the output shall be pretty-printed
-        @param[in] indent_step     the indent level
-        @param[in] current_indent  the current indent level (only used internally)
-        */
-        void dump(const basic_json& val,
-                  const bool pretty_print,
-                  const unsigned int indent_step,
-                  const unsigned int current_indent = 0)
-        {
-            switch (val.m_type)
-            {
-                case value_t::object:
-                {
-                    if (val.m_value.object->empty())
-                    {
-                        o.write("{}", 2);
-                        return;
-                    }
+        assert_invariant();
+    }
 
-                    if (pretty_print)
-                    {
-                        o.write("{\n", 2);
+    /*!
+    @brief copy assignment
 
-                        // variable to hold indentation for recursive calls
-                        const auto new_indent = current_indent + indent_step;
-                        if (indent_string.size() < new_indent)
-                        {
-                            indent_string.resize(new_indent, ' ');
-                        }
+    Copy assignment operator. Copies a JSON value via the "copy and swap"
+    strategy: It is expressed in terms of the copy constructor, destructor,
+    and the `swap()` member function.
 
-                        // first n-1 elements
-                        auto i = val.m_value.object->cbegin();
-                        for (size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
-                        {
-                            o.write(indent_string.c_str(), static_cast<std::streamsize>(new_indent));
-                            o.put('\"');
-                            dump_escaped(i->first);
-                            o.write("\": ", 3);
-                            dump(i->second, true, indent_step, new_indent);
-                            o.write(",\n", 2);
-                        }
+    @param[in] other  value to copy from
 
-                        // last element
-                        assert(i != val.m_value.object->cend());
-                        o.write(indent_string.c_str(), static_cast<std::streamsize>(new_indent));
-                        o.put('\"');
-                        dump_escaped(i->first);
-                        o.write("\": ", 3);
-                        dump(i->second, true, indent_step, new_indent);
-
-                        o.put('\n');
-                        o.write(indent_string.c_str(), static_cast<std::streamsize>(current_indent));
-                        o.put('}');
-                    }
-                    else
-                    {
-                        o.put('{');
+    @complexity Linear.
 
-                        // first n-1 elements
-                        auto i = val.m_value.object->cbegin();
-                        for (size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
-                        {
-                            o.put('\"');
-                            dump_escaped(i->first);
-                            o.write("\":", 2);
-                            dump(i->second, false, indent_step, current_indent);
-                            o.put(',');
-                        }
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
 
-                        // last element
-                        assert(i != val.m_value.object->cend());
-                        o.put('\"');
-                        dump_escaped(i->first);
-                        o.write("\":", 2);
-                        dump(i->second, false, indent_step, current_indent);
+    @liveexample{The code below shows and example for the copy assignment. It
+    creates a copy of value `a` which is then swapped with `b`. Finally\, the
+    copy of `a` (which is the null value after the swap) is
+    destroyed.,basic_json__copyassignment}
 
-                        o.put('}');
-                    }
+    @since version 1.0.0
+    */
+    reference& operator=(basic_json other) noexcept (
+        std::is_nothrow_move_constructible<value_t>::value and
+        std::is_nothrow_move_assignable<value_t>::value and
+        std::is_nothrow_move_constructible<json_value>::value and
+        std::is_nothrow_move_assignable<json_value>::value
+    )
+    {
+        // check that passed value is valid
+        other.assert_invariant();
 
-                    return;
-                }
+        using std::swap;
+        swap(m_type, other.m_type);
+        swap(m_value, other.m_value);
 
-                case value_t::array:
-                {
-                    if (val.m_value.array->empty())
-                    {
-                        o.write("[]", 2);
-                        return;
-                    }
+        assert_invariant();
+        return *this;
+    }
 
-                    if (pretty_print)
-                    {
-                        o.write("[\n", 2);
+    /*!
+    @brief destructor
 
-                        // variable to hold indentation for recursive calls
-                        const auto new_indent = current_indent + indent_step;
-                        if (indent_string.size() < new_indent)
-                        {
-                            indent_string.resize(new_indent, ' ');
-                        }
+    Destroys the JSON value and frees all allocated memory.
 
-                        // first n-1 elements
-                        for (auto i = val.m_value.array->cbegin(); i != val.m_value.array->cend() - 1; ++i)
-                        {
-                            o.write(indent_string.c_str(), static_cast<std::streamsize>(new_indent));
-                            dump(*i, true, indent_step, new_indent);
-                            o.write(",\n", 2);
-                        }
+    @complexity Linear.
 
-                        // last element
-                        assert(not val.m_value.array->empty());
-                        o.write(indent_string.c_str(), static_cast<std::streamsize>(new_indent));
-                        dump(val.m_value.array->back(), true, indent_step, new_indent);
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is linear.
+    - All stored elements are destroyed and all memory is freed.
 
-                        o.put('\n');
-                        o.write(indent_string.c_str(), static_cast<std::streamsize>(current_indent));
-                        o.put(']');
-                    }
-                    else
-                    {
-                        o.put('[');
+    @since version 1.0.0
+    */
+    ~basic_json()
+    {
+        assert_invariant();
+        m_value.destroy(m_type);
+    }
 
-                        // first n-1 elements
-                        for (auto i = val.m_value.array->cbegin(); i != val.m_value.array->cend() - 1; ++i)
-                        {
-                            dump(*i, false, indent_step, current_indent);
-                            o.put(',');
-                        }
+    /// @}
 
-                        // last element
-                        assert(not val.m_value.array->empty());
-                        dump(val.m_value.array->back(), false, indent_step, current_indent);
+  public:
+    ///////////////////////
+    // object inspection //
+    ///////////////////////
 
-                        o.put(']');
-                    }
+    /// @name object inspection
+    /// Functions to inspect the type of a JSON value.
+    /// @{
 
-                    return;
-                }
+    /*!
+    @brief serialization
 
-                case value_t::string:
-                {
-                    o.put('\"');
-                    dump_escaped(*val.m_value.string);
-                    o.put('\"');
-                    return;
-                }
+    Serialization function for JSON values. The function tries to mimic
+    Python's `json.dumps()` function, and currently supports its @a indent
+    and @a ensure_ascii parameters.
 
-                case value_t::boolean:
-                {
-                    if (val.m_value.boolean)
-                    {
-                        o.write("true", 4);
-                    }
-                    else
-                    {
-                        o.write("false", 5);
-                    }
-                    return;
-                }
+    @param[in] indent If indent is nonnegative, then array elements and object
+    members will be pretty-printed with that indent level. An indent level of
+    `0` will only insert newlines. `-1` (the default) selects the most compact
+    representation.
+    @param[in] indent_char The character to use for indentation if @a indent is
+    greater than `0`. The default is ` ` (space).
+    @param[in] ensure_ascii If @a ensure_ascii is true, all non-ASCII characters
+    in the output are escaped with `\uXXXX` sequences, and the result consists
+    of ASCII characters only.
 
-                case value_t::number_integer:
-                {
-                    dump_integer(val.m_value.number_integer);
-                    return;
-                }
+    @return string containing the serialization of the JSON value
 
-                case value_t::number_unsigned:
-                {
-                    dump_integer(val.m_value.number_unsigned);
-                    return;
-                }
+    @throw type_error.316 if a string stored inside the JSON value is not
+                          UTF-8 encoded
 
-                case value_t::number_float:
-                {
-                    dump_float(val.m_value.number_float);
-                    return;
-                }
+    @complexity Linear.
 
-                case value_t::discarded:
-                {
-                    o.write("<discarded>", 11);
-                    return;
-                }
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-                case value_t::null:
-                {
-                    o.write("null", 4);
-                    return;
-                }
-            }
-        }
+    @liveexample{The following example shows the effect of different @a indent\,
+    @a indent_char\, and @a ensure_ascii parameters to the result of the
+    serialization.,dump}
 
-      private:
-        /*!
-        @brief calculates the extra space to escape a JSON string
+    @see https://docs.python.org/2/library/json.html#json.dump
 
-        @param[in] s  the string to escape
-        @return the number of characters required to escape string @a s
+    @since version 1.0.0; indentation character @a indent_char, option
+           @a ensure_ascii and exceptions added in version 3.0.0
+    */
+    string_t dump(const int indent = -1, const char indent_char = ' ',
+                  const bool ensure_ascii = false) const
+    {
+        string_t result;
+        serializer s(detail::output_adapter<char>(result), indent_char);
 
-        @complexity Linear in the length of string @a s.
-        */
-        static std::size_t extra_space(const string_t& s) noexcept
+        if (indent >= 0)
         {
-            return std::accumulate(s.begin(), s.end(), size_t{},
-                                   [](size_t res, typename string_t::value_type c)
-            {
-                switch (c)
-                {
-                    case '"':
-                    case '\\':
-                    case '\b':
-                    case '\f':
-                    case '\n':
-                    case '\r':
-                    case '\t':
-                    {
-                        // from c (1 byte) to \x (2 bytes)
-                        return res + 1;
-                    }
+            s.dump(*this, true, ensure_ascii, static_cast<unsigned int>(indent));
+        }
+        else
+        {
+            s.dump(*this, false, ensure_ascii, 0);
+        }
 
-                    case 0x00:
-                    case 0x01:
-                    case 0x02:
-                    case 0x03:
-                    case 0x04:
-                    case 0x05:
-                    case 0x06:
-                    case 0x07:
-                    case 0x0b:
-                    case 0x0e:
-                    case 0x0f:
-                    case 0x10:
-                    case 0x11:
-                    case 0x12:
-                    case 0x13:
-                    case 0x14:
-                    case 0x15:
-                    case 0x16:
-                    case 0x17:
-                    case 0x18:
-                    case 0x19:
-                    case 0x1a:
-                    case 0x1b:
-                    case 0x1c:
-                    case 0x1d:
-                    case 0x1e:
-                    case 0x1f:
-                    {
-                        // from c (1 byte) to \uxxxx (6 bytes)
-                        return res + 5;
-                    }
+        return result;
+    }
 
-                    default:
-                    {
-                        return res;
-                    }
-                }
-            });
-        }
+    /*!
+    @brief return the type of the JSON value (explicit)
 
-        /*!
-        @brief dump escaped string
+    Return the type of the JSON value as a value from the @ref value_t
+    enumeration.
 
-        Escape a string by replacing certain special characters by a sequence
-        of an escape character (backslash) and another character and other
-        control characters by a sequence of "\u" followed by a four-digit hex
-        representation. The escaped string is written to output stream @a o.
+    @return the type of the JSON value
+            Value type                | return value
+            ------------------------- | -------------------------
+            null                      | value_t::null
+            boolean                   | value_t::boolean
+            string                    | value_t::string
+            number (integer)          | value_t::number_integer
+            number (unsigned integer) | value_t::number_unsigned
+            number (floating-point)   | value_t::number_float
+            object                    | value_t::object
+            array                     | value_t::array
+            discarded                 | value_t::discarded
 
-        @param[in] s  the string to escape
+    @complexity Constant.
 
-        @complexity Linear in the length of string @a s.
-        */
-        void dump_escaped(const string_t& s) const
-        {
-            const auto space = extra_space(s);
-            if (space == 0)
-            {
-                o.write(s.c_str(), static_cast<std::streamsize>(s.size()));
-                return;
-            }
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-            // create a result string of necessary size
-            string_t result(s.size() + space, '\\');
-            std::size_t pos = 0;
+    @liveexample{The following code exemplifies `type()` for all JSON
+    types.,type}
 
-            for (const auto& c : s)
-            {
-                switch (c)
-                {
-                    // quotation mark (0x22)
-                    case '"':
-                    {
-                        result[pos + 1] = '"';
-                        pos += 2;
-                        break;
-                    }
+    @sa @ref operator value_t() -- return the type of the JSON value (implicit)
+    @sa @ref type_name() -- return the type as string
 
-                    // reverse solidus (0x5c)
-                    case '\\':
-                    {
-                        // nothing to change
-                        pos += 2;
-                        break;
-                    }
-
-                    // backspace (0x08)
-                    case '\b':
-                    {
-                        result[pos + 1] = 'b';
-                        pos += 2;
-                        break;
-                    }
-
-                    // formfeed (0x0c)
-                    case '\f':
-                    {
-                        result[pos + 1] = 'f';
-                        pos += 2;
-                        break;
-                    }
-
-                    // newline (0x0a)
-                    case '\n':
-                    {
-                        result[pos + 1] = 'n';
-                        pos += 2;
-                        break;
-                    }
+    @since version 1.0.0
+    */
+    constexpr value_t type() const noexcept
+    {
+        return m_type;
+    }
 
-                    // carriage return (0x0d)
-                    case '\r':
-                    {
-                        result[pos + 1] = 'r';
-                        pos += 2;
-                        break;
-                    }
+    /*!
+    @brief return whether type is primitive
 
-                    // horizontal tab (0x09)
-                    case '\t':
-                    {
-                        result[pos + 1] = 't';
-                        pos += 2;
-                        break;
-                    }
+    This function returns true if and only if the JSON type is primitive
+    (string, number, boolean, or null).
 
-                    case 0x00:
-                    case 0x01:
-                    case 0x02:
-                    case 0x03:
-                    case 0x04:
-                    case 0x05:
-                    case 0x06:
-                    case 0x07:
-                    case 0x0b:
-                    case 0x0e:
-                    case 0x0f:
-                    case 0x10:
-                    case 0x11:
-                    case 0x12:
-                    case 0x13:
-                    case 0x14:
-                    case 0x15:
-                    case 0x16:
-                    case 0x17:
-                    case 0x18:
-                    case 0x19:
-                    case 0x1a:
-                    case 0x1b:
-                    case 0x1c:
-                    case 0x1d:
-                    case 0x1e:
-                    case 0x1f:
-                    {
-                        // convert a number 0..15 to its hex representation
-                        // (0..f)
-                        static const char hexify[16] =
-                        {
-                            '0', '1', '2', '3', '4', '5', '6', '7',
-                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
-                        };
-
-                        // print character c as \uxxxx
-                        for (const char m :
-                    { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f]
-                        })
-                        {
-                            result[++pos] = m;
-                        }
+    @return `true` if type is primitive (string, number, boolean, or null),
+    `false` otherwise.
 
-                        ++pos;
-                        break;
-                    }
+    @complexity Constant.
 
-                    default:
-                    {
-                        // all other characters are added as-is
-                        result[pos++] = c;
-                        break;
-                    }
-                }
-            }
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-            assert(pos == s.size() + space);
-            o.write(result.c_str(), static_cast<std::streamsize>(result.size()));
-        }
+    @liveexample{The following code exemplifies `is_primitive()` for all JSON
+    types.,is_primitive}
 
-        /*!
-        @brief dump an integer
+    @sa @ref is_structured() -- returns whether JSON value is structured
+    @sa @ref is_null() -- returns whether JSON value is `null`
+    @sa @ref is_string() -- returns whether JSON value is a string
+    @sa @ref is_boolean() -- returns whether JSON value is a boolean
+    @sa @ref is_number() -- returns whether JSON value is a number
 
-        Dump a given integer to output stream @a o. Works internally with
-        @a number_buffer.
+    @since version 1.0.0
+    */
+    constexpr bool is_primitive() const noexcept
+    {
+        return is_null() or is_string() or is_boolean() or is_number();
+    }
 
-        @param[in] x  integer number (signed or unsigned) to dump
-        @tparam NumberType either @a number_integer_t or @a number_unsigned_t
-        */
-        template<typename NumberType, detail::enable_if_t <
-                     std::is_same<NumberType, number_unsigned_t>::value or
-                     std::is_same<NumberType, number_integer_t>::value, int> = 0>
-        void dump_integer(NumberType x)
-        {
-            // special case for "0"
-            if (x == 0)
-            {
-                o.put('0');
-                return;
-            }
+    /*!
+    @brief return whether type is structured
 
-            const bool is_negative = x < 0;
-            size_t i = 0;
+    This function returns true if and only if the JSON type is structured
+    (array or object).
 
-            // spare 1 byte for '\0'
-            while (x != 0 and i < number_buffer.size() - 1)
-            {
-                const auto digit = std::labs(static_cast<long>(x % 10));
-                number_buffer[i++] = static_cast<char>('0' + digit);
-                x /= 10;
-            }
+    @return `true` if type is structured (array or object), `false` otherwise.
 
-            // make sure the number has been processed completely
-            assert(x == 0);
+    @complexity Constant.
 
-            if (is_negative)
-            {
-                // make sure there is capacity for the '-'
-                assert(i < number_buffer.size() - 2);
-                number_buffer[i++] = '-';
-            }
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-            std::reverse(number_buffer.begin(), number_buffer.begin() + i);
-            o.write(number_buffer.data(), static_cast<std::streamsize>(i));
-        }
+    @liveexample{The following code exemplifies `is_structured()` for all JSON
+    types.,is_structured}
 
-        /*!
-        @brief dump a floating-point number
+    @sa @ref is_primitive() -- returns whether value is primitive
+    @sa @ref is_array() -- returns whether value is an array
+    @sa @ref is_object() -- returns whether value is an object
 
-        Dump a given floating-point number to output stream @a o. Works
-        internally with @a number_buffer.
+    @since version 1.0.0
+    */
+    constexpr bool is_structured() const noexcept
+    {
+        return is_array() or is_object();
+    }
 
-        @param[in] x  floating-point number to dump
-        */
-        void dump_float(number_float_t x)
-        {
-            // NaN / inf
-            if (not std::isfinite(x) or std::isnan(x))
-            {
-                o.write("null", 4);
-                return;
-            }
+    /*!
+    @brief return whether value is null
 
-            // special case for 0.0 and -0.0
-            if (x == 0)
-            {
-                if (std::signbit(x))
-                {
-                    o.write("-0.0", 4);
-                }
-                else
-                {
-                    o.write("0.0", 3);
-                }
-                return;
-            }
+    This function returns true if and only if the JSON value is null.
 
-            // get number of digits for a text -> float -> text round-trip
-            static constexpr auto d = std::numeric_limits<number_float_t>::digits10;
+    @return `true` if type is null, `false` otherwise.
 
-            // the actual conversion
-            std::ptrdiff_t len = snprintf(number_buffer.data(), number_buffer.size(),
-                                          "%.*g", d, x);
+    @complexity Constant.
 
-            // negative value indicates an error
-            assert(len > 0);
-            // check if buffer was large enough
-            assert(static_cast<size_t>(len) < number_buffer.size());
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-            // erase thousands separator
-            if (thousands_sep != '\0')
-            {
-                const auto end = std::remove(number_buffer.begin(),
-                                             number_buffer.begin() + len,
-                                             thousands_sep);
-                std::fill(end, number_buffer.end(), '\0');
-                assert((end - number_buffer.begin()) <= len);
-                len = (end - number_buffer.begin());
-            }
+    @liveexample{The following code exemplifies `is_null()` for all JSON
+    types.,is_null}
 
-            // convert decimal point to '.'
-            if (decimal_point != '\0' and decimal_point != '.')
-            {
-                for (auto& c : number_buffer)
-                {
-                    if (c == decimal_point)
-                    {
-                        c = '.';
-                        break;
-                    }
-                }
-            }
+    @since version 1.0.0
+    */
+    constexpr bool is_null() const noexcept
+    {
+        return (m_type == value_t::null);
+    }
 
-            o.write(number_buffer.data(), static_cast<std::streamsize>(len));
+    /*!
+    @brief return whether value is a boolean
 
-            // determine if need to append ".0"
-            const bool value_is_int_like = std::none_of(number_buffer.begin(),
-                                           number_buffer.begin() + len + 1,
-                                           [](char c)
-            {
-                return c == '.' or c == 'e';
-            });
+    This function returns true if and only if the JSON value is a boolean.
 
-            if (value_is_int_like)
-            {
-                o.write(".0", 2);
-            }
-        }
+    @return `true` if type is boolean, `false` otherwise.
 
-      private:
-        /// the output of the serializer
-        std::ostream& o;
+    @complexity Constant.
 
-        /// a (hopefully) large enough character buffer
-        std::array<char, 64> number_buffer{{}};
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-        /// the locale
-        const std::lconv* loc = nullptr;
-        /// the locale's thousand separator character
-        const char thousands_sep = '\0';
-        /// the locale's decimal point character
-        const char decimal_point = '\0';
+    @liveexample{The following code exemplifies `is_boolean()` for all JSON
+    types.,is_boolean}
 
-        /// the indentation string
-        string_t indent_string = string_t(512, ' ');
-    };
+    @since version 1.0.0
+    */
+    constexpr bool is_boolean() const noexcept
+    {
+        return (m_type == value_t::boolean);
+    }
 
-  public:
     /*!
-    @brief serialize to stream
+    @brief return whether value is a number
 
-    Serialize the given JSON value @a j to the output stream @a o. The JSON
-    value will be serialized using the @ref dump member function. The
-    indentation of the output can be controlled with the member variable
-    `width` of the output stream @a o. For instance, using the manipulator
-    `std::setw(4)` on @a o sets the indentation level to `4` and the
-    serialization result is the same as calling `dump(4)`.
+    This function returns true if and only if the JSON value is a number. This
+    includes both integer (signed and unsigned) and floating-point values.
 
-    @param[in,out] o  stream to serialize to
-    @param[in] j  JSON value to serialize
+    @return `true` if type is number (regardless whether integer, unsigned
+    integer or floating-type), `false` otherwise.
 
-    @return the stream @a o
+    @complexity Constant.
 
-    @complexity Linear.
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    @liveexample{The example below shows the serialization with different
-    parameters to `width` to adjust the indentation level.,operator_serialize}
+    @liveexample{The following code exemplifies `is_number()` for all JSON
+    types.,is_number}
+
+    @sa @ref is_number_integer() -- check if value is an integer or unsigned
+    integer number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
+    @sa @ref is_number_float() -- check if value is a floating-point number
 
     @since version 1.0.0
     */
-    friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
+    constexpr bool is_number() const noexcept
     {
-        // read width member and use it as indentation parameter if nonzero
-        const bool pretty_print = (o.width() > 0);
-        const auto indentation = (pretty_print ? o.width() : 0);
-
-        // reset width to 0 for subsequent calls to this stream
-        o.width(0);
-
-        // do the actual serialization
-        serializer s(o);
-        s.dump(j, pretty_print, static_cast<unsigned int>(indentation));
-        return o;
+        return is_number_integer() or is_number_float();
     }
 
     /*!
-    @brief serialize to stream
-    @deprecated This stream operator is deprecated and will be removed in a
-                future version of the library. Please use
-                @ref std::ostream& operator<<(std::ostream&, const basic_json&)
-                instead; that is, replace calls like `j >> o;` with `o << j;`.
-    */
-    JSON_DEPRECATED
-    friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
-    {
-        return o << j;
-    }
+    @brief return whether value is an integer number
 
-    /// @}
+    This function returns true if and only if the JSON value is a signed or
+    unsigned integer number. This excludes floating-point values.
 
+    @return `true` if type is an integer or unsigned integer number, `false`
+    otherwise.
 
-    /////////////////////
-    // deserialization //
-    /////////////////////
+    @complexity Constant.
 
-    /// @name deserialization
-    /// @{
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    /*!
-    @brief deserialize from an array
+    @liveexample{The following code exemplifies `is_number_integer()` for all
+    JSON types.,is_number_integer}
 
-    This function reads from an array of 1-byte values.
+    @sa @ref is_number() -- check if value is a number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
+    @sa @ref is_number_float() -- check if value is a floating-point number
 
-    @pre Each element of the container has a size of 1 byte. Violating this
-    precondition yields undefined behavior. **This precondition is enforced
-    with a static assertion.**
+    @since version 1.0.0
+    */
+    constexpr bool is_number_integer() const noexcept
+    {
+        return (m_type == value_t::number_integer or m_type == value_t::number_unsigned);
+    }
 
-    @param[in] array  array to read from
-    @param[in] cb  a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
+    /*!
+    @brief return whether value is an unsigned integer number
 
-    @return result of the deserialization
+    This function returns true if and only if the JSON value is an unsigned
+    integer number. This excludes floating-point and signed integer values.
 
-    @throw parse_error.101 if a parse error occurs; example: `""unexpected end
-    of input; expected string literal""`
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
+    @return `true` if type is an unsigned integer number, `false` otherwise.
 
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
+    @complexity Constant.
 
-    @note A UTF-8 byte order mark is silently ignored.
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    @liveexample{The example below demonstrates the `parse()` function reading
-    from an array.,parse__array__parser_callback_t}
+    @liveexample{The following code exemplifies `is_number_unsigned()` for all
+    JSON types.,is_number_unsigned}
 
-    @since version 2.0.3
+    @sa @ref is_number() -- check if value is a number
+    @sa @ref is_number_integer() -- check if value is an integer or unsigned
+    integer number
+    @sa @ref is_number_float() -- check if value is a floating-point number
+
+    @since version 2.0.0
     */
-    template<class T, std::size_t N>
-    static basic_json parse(T (&array)[N],
-                            const parser_callback_t cb = nullptr)
+    constexpr bool is_number_unsigned() const noexcept
     {
-        // delegate the call to the iterator-range parse overload
-        return parse(std::begin(array), std::end(array), cb);
+        return (m_type == value_t::number_unsigned);
     }
 
     /*!
-    @brief deserialize from string literal
+    @brief return whether value is a floating-point number
 
-    @tparam CharT character/literal type with size of 1 byte
-    @param[in] s  string literal to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
+    This function returns true if and only if the JSON value is a
+    floating-point number. This excludes signed and unsigned integer values.
 
-    @return result of the deserialization
+    @return `true` if type is a floating-point number, `false` otherwise.
 
-    @throw parse_error.101 in case of an unexpected token
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
+    @complexity Constant.
 
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-    @note String containers like `std::string` or @ref string_t can be parsed
-          with @ref parse(const ContiguousContainer&, const parser_callback_t)
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    @liveexample{The example below demonstrates the `parse()` function with
-    and without callback function.,parse__string__parser_callback_t}
+    @liveexample{The following code exemplifies `is_number_float()` for all
+    JSON types.,is_number_float}
 
-    @sa @ref parse(std::istream&, const parser_callback_t) for a version that
-    reads from an input stream
+    @sa @ref is_number() -- check if value is number
+    @sa @ref is_number_integer() -- check if value is an integer number
+    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    number
 
-    @since version 1.0.0 (originally for @ref string_t)
+    @since version 1.0.0
     */
-    template<typename CharT, typename std::enable_if<
-                 std::is_pointer<CharT>::value and
-                 std::is_integral<typename std::remove_pointer<CharT>::type>::value and
-                 sizeof(typename std::remove_pointer<CharT>::type) == 1, int>::type = 0>
-    static basic_json parse(const CharT s,
-                            const parser_callback_t cb = nullptr)
+    constexpr bool is_number_float() const noexcept
     {
-        return parser(reinterpret_cast<const char*>(s), cb).parse();
+        return (m_type == value_t::number_float);
     }
 
     /*!
-    @brief deserialize from stream
-
-    @param[in,out] i  stream to read a serialized JSON value from
-    @param[in] cb a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-
-    @return result of the deserialization
+    @brief return whether value is an object
 
-    @throw parse_error.101 in case of an unexpected token
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
-    @throw parse_error.111 if input stream is in a bad state
+    This function returns true if and only if the JSON value is an object.
 
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
+    @return `true` if type is object, `false` otherwise.
 
-    @note A UTF-8 byte order mark is silently ignored.
+    @complexity Constant.
 
-    @liveexample{The example below demonstrates the `parse()` function with
-    and without callback function.,parse__istream__parser_callback_t}
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    @sa @ref parse(const CharT, const parser_callback_t) for a version
-    that reads from a string
+    @liveexample{The following code exemplifies `is_object()` for all JSON
+    types.,is_object}
 
     @since version 1.0.0
     */
-    static basic_json parse(std::istream& i,
-                            const parser_callback_t cb = nullptr)
-    {
-        return parser(i, cb).parse();
-    }
-
-    /*!
-    @copydoc parse(std::istream&, const parser_callback_t)
-    */
-    static basic_json parse(std::istream&& i,
-                            const parser_callback_t cb = nullptr)
+    constexpr bool is_object() const noexcept
     {
-        return parser(i, cb).parse();
+        return (m_type == value_t::object);
     }
 
     /*!
-    @brief deserialize from an iterator range with contiguous storage
-
-    This function reads from an iterator range of a container with contiguous
-    storage of 1-byte values. Compatible container types include
-    `std::vector`, `std::string`, `std::array`, `std::valarray`, and
-    `std::initializer_list`. Furthermore, C-style arrays can be used with
-    `std::begin()`/`std::end()`. User-defined containers can be used as long
-    as they implement random-access iterators and a contiguous storage.
-
-    @pre The iterator range is contiguous. Violating this precondition yields
-    undefined behavior. **This precondition is enforced with an assertion.**
-    @pre Each element in the range has a size of 1 byte. Violating this
-    precondition yields undefined behavior. **This precondition is enforced
-    with a static assertion.**
-
-    @warning There is no way to enforce all preconditions at compile-time. If
-             the function is called with noncompliant iterators and with
-             assertions switched off, the behavior is undefined and will most
-             likely yield segmentation violation.
-
-    @tparam IteratorType iterator of container with contiguous storage
-    @param[in] first  begin of the range to parse (included)
-    @param[in] last  end of the range to parse (excluded)
-    @param[in] cb  a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
+    @brief return whether value is an array
 
-    @return result of the deserialization
+    This function returns true if and only if the JSON value is an array.
 
-    @throw parse_error.101 in case of an unexpected token
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
+    @return `true` if type is array, `false` otherwise.
 
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
+    @complexity Constant.
 
-    @note A UTF-8 byte order mark is silently ignored.
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    @liveexample{The example below demonstrates the `parse()` function reading
-    from an iterator range.,parse__iteratortype__parser_callback_t}
+    @liveexample{The following code exemplifies `is_array()` for all JSON
+    types.,is_array}
 
-    @since version 2.0.3
+    @since version 1.0.0
     */
-    template<class IteratorType, typename std::enable_if<
-                 std::is_base_of<
-                     std::random_access_iterator_tag,
-                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
-    static basic_json parse(IteratorType first, IteratorType last,
-                            const parser_callback_t cb = nullptr)
+    constexpr bool is_array() const noexcept
     {
-        // assertion to check that the iterator range is indeed contiguous,
-        // see http://stackoverflow.com/a/35008842/266378 for more discussion
-        assert(std::accumulate(first, last, std::pair<bool, int>(true, 0),
-                               [&first](std::pair<bool, int> res, decltype(*first) val)
-        {
-            res.first &= (val == *(std::next(std::addressof(*first), res.second++)));
-            return res;
-        }).first);
+        return (m_type == value_t::array);
+    }
 
-        // assertion to check that each element is 1 byte long
-        static_assert(sizeof(typename std::iterator_traits<IteratorType>::value_type) == 1,
-                      "each element in the iterator range must have the size of 1 byte");
+    /*!
+    @brief return whether value is a string
 
-        // if iterator range is empty, create a parser with an empty string
-        // to generate "unexpected EOF" error message
-        if (std::distance(first, last) <= 0)
-        {
-            return parser("").parse();
-        }
+    This function returns true if and only if the JSON value is a string.
 
-        return parser(first, last, cb).parse();
-    }
+    @return `true` if type is string, `false` otherwise.
 
-    /*!
-    @brief deserialize from a container with contiguous storage
+    @complexity Constant.
 
-    This function reads from a container with contiguous storage of 1-byte
-    values. Compatible container types include `std::vector`, `std::string`,
-    `std::array`, and `std::initializer_list`. User-defined containers can be
-    used as long as they implement random-access iterators and a contiguous
-    storage.
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    @pre The container storage is contiguous. Violating this precondition
-    yields undefined behavior. **This precondition is enforced with an
-    assertion.**
-    @pre Each element of the container has a size of 1 byte. Violating this
-    precondition yields undefined behavior. **This precondition is enforced
-    with a static assertion.**
+    @liveexample{The following code exemplifies `is_string()` for all JSON
+    types.,is_string}
 
-    @warning There is no way to enforce all preconditions at compile-time. If
-             the function is called with a noncompliant container and with
-             assertions switched off, the behavior is undefined and will most
-             likely yield segmentation violation.
+    @since version 1.0.0
+    */
+    constexpr bool is_string() const noexcept
+    {
+        return (m_type == value_t::string);
+    }
 
-    @tparam ContiguousContainer container type with contiguous storage
-    @param[in] c  container to read from
-    @param[in] cb  a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
+    /*!
+    @brief return whether value is discarded
 
-    @return result of the deserialization
+    This function returns true if and only if the JSON value was discarded
+    during parsing with a callback function (see @ref parser_callback_t).
 
-    @throw parse_error.101 in case of an unexpected token
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
+    @note This function will always be `false` for JSON values after parsing.
+    That is, discarded values can only occur during parsing, but will be
+    removed when inside a structured value or replaced by null in other cases.
 
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
+    @return `true` if type is discarded, `false` otherwise.
 
-    @note A UTF-8 byte order mark is silently ignored.
+    @complexity Constant.
 
-    @liveexample{The example below demonstrates the `parse()` function reading
-    from a contiguous container.,parse__contiguouscontainer__parser_callback_t}
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    @since version 2.0.3
-    */
-    template<class ContiguousContainer, typename std::enable_if<
-                 not std::is_pointer<ContiguousContainer>::value and
-                 std::is_base_of<
-                     std::random_access_iterator_tag,
-                     typename std::iterator_traits<decltype(std::begin(std::declval<ContiguousContainer const>()))>::iterator_category>::value
-                 , int>::type = 0>
-    static basic_json parse(const ContiguousContainer& c,
-                            const parser_callback_t cb = nullptr)
-    {
-        // delegate the call to the iterator-range parse overload
-        return parse(std::begin(c), std::end(c), cb);
-    }
+    @liveexample{The following code exemplifies `is_discarded()` for all JSON
+    types.,is_discarded}
 
-    /*!
-    @brief deserialize from stream
-    @deprecated This stream operator is deprecated and will be removed in a
-                future version of the library. Please use
-                @ref std::istream& operator>>(std::istream&, basic_json&)
-                instead; that is, replace calls like `j << i;` with `i >> j;`.
+    @since version 1.0.0
     */
-    JSON_DEPRECATED
-    friend std::istream& operator<<(basic_json& j, std::istream& i)
+    constexpr bool is_discarded() const noexcept
     {
-        j = parser(i).parse();
-        return i;
+        return (m_type == value_t::discarded);
     }
 
     /*!
-    @brief deserialize from stream
-
-    Deserializes an input stream to a JSON value.
+    @brief return the type of the JSON value (implicit)
 
-    @param[in,out] i  input stream to read a serialized JSON value from
-    @param[in,out] j  JSON value to write the deserialized input to
+    Implicitly return the type of the JSON value as a value from the @ref
+    value_t enumeration.
 
-    @throw parse_error.101 in case of an unexpected token
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
-    @throw parse_error.111 if input stream is in a bad state
+    @return the type of the JSON value
 
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser.
+    @complexity Constant.
 
-    @note A UTF-8 byte order mark is silently ignored.
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    @liveexample{The example below shows how a JSON value is constructed by
-    reading a serialization from a stream.,operator_deserialize}
+    @liveexample{The following code exemplifies the @ref value_t operator for
+    all JSON types.,operator__value_t}
 
-    @sa parse(std::istream&, const parser_callback_t) for a variant with a
-    parser callback function to filter values while parsing
+    @sa @ref type() -- return the type of the JSON value (explicit)
+    @sa @ref type_name() -- return the type as string
 
     @since version 1.0.0
     */
-    friend std::istream& operator>>(std::istream& i, basic_json& j)
+    constexpr operator value_t() const noexcept
     {
-        j = parser(i).parse();
-        return i;
+        return m_type;
     }
 
     /// @}
 
-    //////////////////////////////////////////
-    // binary serialization/deserialization //
-    //////////////////////////////////////////
-
-    /// @name binary serialization/deserialization support
-    /// @{
-
   private:
-    /*!
-    @note Some code in the switch cases has been copied, because otherwise
-          copilers would complain about implicit fallthrough and there is no
-          portable attribute to mute such warnings.
-    */
-    template<typename T>
-    static void add_to_vector(std::vector<uint8_t>& vec, size_t bytes, const T number)
-    {
-        assert(bytes == 1 or bytes == 2 or bytes == 4 or bytes == 8);
+    //////////////////
+    // value access //
+    //////////////////
 
-        switch (bytes)
+    /// get a boolean (explicit)
+    boolean_t get_impl(boolean_t* /*unused*/) const
+    {
+        if (JSON_LIKELY(is_boolean()))
         {
-            case 8:
-            {
-                vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 070) & 0xff));
-                vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 060) & 0xff));
-                vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 050) & 0xff));
-                vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 040) & 0xff));
-                vec.push_back(static_cast<uint8_t>((number >> 030) & 0xff));
-                vec.push_back(static_cast<uint8_t>((number >> 020) & 0xff));
-                vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff));
-                vec.push_back(static_cast<uint8_t>(number & 0xff));
-                break;
-            }
-
-            case 4:
-            {
-                vec.push_back(static_cast<uint8_t>((number >> 030) & 0xff));
-                vec.push_back(static_cast<uint8_t>((number >> 020) & 0xff));
-                vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff));
-                vec.push_back(static_cast<uint8_t>(number & 0xff));
-                break;
-            }
-
-            case 2:
-            {
-                vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff));
-                vec.push_back(static_cast<uint8_t>(number & 0xff));
-                break;
-            }
-
-            case 1:
-            {
-                vec.push_back(static_cast<uint8_t>(number & 0xff));
-                break;
-            }
+            return m_value.boolean;
         }
-    }
-
-    /*!
-    @brief take sufficient bytes from a vector to fill an integer variable
 
-    In the context of binary serialization formats, we need to read several
-    bytes from a byte vector and combine them to multi-byte integral data
-    types.
+        JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(type_name())));
+    }
 
-    @param[in] vec  byte vector to read from
-    @param[in] current_index  the position in the vector after which to read
+    /// get a pointer to the value (object)
+    object_t* get_impl_ptr(object_t* /*unused*/) noexcept
+    {
+        return is_object() ? m_value.object : nullptr;
+    }
 
-    @return the next sizeof(T) bytes from @a vec, in reverse order as T
+    /// get a pointer to the value (object)
+    constexpr const object_t* get_impl_ptr(const object_t* /*unused*/) const noexcept
+    {
+        return is_object() ? m_value.object : nullptr;
+    }
 
-    @tparam T the integral return type
+    /// get a pointer to the value (array)
+    array_t* get_impl_ptr(array_t* /*unused*/) noexcept
+    {
+        return is_array() ? m_value.array : nullptr;
+    }
 
-    @throw parse_error.110 if there are less than sizeof(T)+1 bytes in the
-           vector @a vec to read
+    /// get a pointer to the value (array)
+    constexpr const array_t* get_impl_ptr(const array_t* /*unused*/) const noexcept
+    {
+        return is_array() ? m_value.array : nullptr;
+    }
 
-    In the for loop, the bytes from the vector are copied in reverse order into
-    the return value. In the figures below, let sizeof(T)=4 and `i` be the loop
-    variable.
+    /// get a pointer to the value (string)
+    string_t* get_impl_ptr(string_t* /*unused*/) noexcept
+    {
+        return is_string() ? m_value.string : nullptr;
+    }
 
-    Precondition:
+    /// get a pointer to the value (string)
+    constexpr const string_t* get_impl_ptr(const string_t* /*unused*/) const noexcept
+    {
+        return is_string() ? m_value.string : nullptr;
+    }
 
-    vec:   |   |   | a | b | c | d |      T: |   |   |   |   |
-                 ^               ^             ^                ^
-           current_index         i            ptr        sizeof(T)
+    /// get a pointer to the value (boolean)
+    boolean_t* get_impl_ptr(boolean_t* /*unused*/) noexcept
+    {
+        return is_boolean() ? &m_value.boolean : nullptr;
+    }
 
-    Postcondition:
+    /// get a pointer to the value (boolean)
+    constexpr const boolean_t* get_impl_ptr(const boolean_t* /*unused*/) const noexcept
+    {
+        return is_boolean() ? &m_value.boolean : nullptr;
+    }
 
-    vec:   |   |   | a | b | c | d |      T: | d | c | b | a |
-                 ^   ^                                     ^
-                 |   i                                    ptr
-           current_index
+    /// get a pointer to the value (integer number)
+    number_integer_t* get_impl_ptr(number_integer_t* /*unused*/) noexcept
+    {
+        return is_number_integer() ? &m_value.number_integer : nullptr;
+    }
 
-    @sa Code adapted from <http://stackoverflow.com/a/41031865/266378>.
-    */
-    template<typename T>
-    static T get_from_vector(const std::vector<uint8_t>& vec, const size_t current_index)
+    /// get a pointer to the value (integer number)
+    constexpr const number_integer_t* get_impl_ptr(const number_integer_t* /*unused*/) const noexcept
     {
-        // check if we can read sizeof(T) bytes starting the next index
-        check_length(vec.size(), sizeof(T), current_index + 1);
+        return is_number_integer() ? &m_value.number_integer : nullptr;
+    }
 
-        T result;
-        auto* ptr = reinterpret_cast<uint8_t*>(&result);
-        for (size_t i = 0; i < sizeof(T); ++i)
-        {
-            *ptr++ = vec[current_index + sizeof(T) - i];
-        }
-        return result;
+    /// get a pointer to the value (unsigned number)
+    number_unsigned_t* get_impl_ptr(number_unsigned_t* /*unused*/) noexcept
+    {
+        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
+    }
+
+    /// get a pointer to the value (unsigned number)
+    constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t* /*unused*/) const noexcept
+    {
+        return is_number_unsigned() ? &m_value.number_unsigned : nullptr;
+    }
+
+    /// get a pointer to the value (floating-point number)
+    number_float_t* get_impl_ptr(number_float_t* /*unused*/) noexcept
+    {
+        return is_number_float() ? &m_value.number_float : nullptr;
+    }
+
+    /// get a pointer to the value (floating-point number)
+    constexpr const number_float_t* get_impl_ptr(const number_float_t* /*unused*/) const noexcept
+    {
+        return is_number_float() ? &m_value.number_float : nullptr;
     }
 
     /*!
-    @brief create a MessagePack serialization of a given JSON value
+    @brief helper function to implement get_ref()
 
-    This is a straightforward implementation of the MessagePack specification.
+    This function helps to implement get_ref() without code duplication for
+    const and non-const overloads
 
-    @param[in] j  JSON value to serialize
-    @param[in,out] v  byte vector to write the serialization to
+    @tparam ThisType will be deduced as `basic_json` or `const basic_json`
 
-    @sa https://github.com/msgpack/msgpack/blob/master/spec.md
+    @throw type_error.303 if ReferenceType does not match underlying value
+    type of the current JSON
     */
-    static void to_msgpack_internal(const basic_json& j, std::vector<uint8_t>& v)
+    template<typename ReferenceType, typename ThisType>
+    static ReferenceType get_ref_impl(ThisType& obj)
     {
-        switch (j.type())
-        {
-            case value_t::null:
-            {
-                // nil
-                v.push_back(0xc0);
-                break;
-            }
-
-            case value_t::boolean:
-            {
-                // true and false
-                v.push_back(j.m_value.boolean ? 0xc3 : 0xc2);
-                break;
-            }
-
-            case value_t::number_integer:
-            {
-                if (j.m_value.number_integer >= 0)
-                {
-                    // MessagePack does not differentiate between positive
-                    // signed integers and unsigned integers. Therefore, we
-                    // used the code from the value_t::number_unsigned case
-                    // here.
-                    if (j.m_value.number_unsigned < 128)
-                    {
-                        // positive fixnum
-                        add_to_vector(v, 1, j.m_value.number_unsigned);
-                    }
-                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
-                    {
-                        // uint 8
-                        v.push_back(0xcc);
-                        add_to_vector(v, 1, j.m_value.number_unsigned);
-                    }
-                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
-                    {
-                        // uint 16
-                        v.push_back(0xcd);
-                        add_to_vector(v, 2, j.m_value.number_unsigned);
-                    }
-                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
-                    {
-                        // uint 32
-                        v.push_back(0xce);
-                        add_to_vector(v, 4, j.m_value.number_unsigned);
-                    }
-                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)())
-                    {
-                        // uint 64
-                        v.push_back(0xcf);
-                        add_to_vector(v, 8, j.m_value.number_unsigned);
-                    }
-                }
-                else
-                {
-                    if (j.m_value.number_integer >= -32)
-                    {
-                        // negative fixnum
-                        add_to_vector(v, 1, j.m_value.number_integer);
-                    }
-                    else if (j.m_value.number_integer >= (std::numeric_limits<int8_t>::min)() and j.m_value.number_integer <= (std::numeric_limits<int8_t>::max)())
-                    {
-                        // int 8
-                        v.push_back(0xd0);
-                        add_to_vector(v, 1, j.m_value.number_integer);
-                    }
-                    else if (j.m_value.number_integer >= (std::numeric_limits<int16_t>::min)() and j.m_value.number_integer <= (std::numeric_limits<int16_t>::max)())
-                    {
-                        // int 16
-                        v.push_back(0xd1);
-                        add_to_vector(v, 2, j.m_value.number_integer);
-                    }
-                    else if (j.m_value.number_integer >= (std::numeric_limits<int32_t>::min)() and j.m_value.number_integer <= (std::numeric_limits<int32_t>::max)())
-                    {
-                        // int 32
-                        v.push_back(0xd2);
-                        add_to_vector(v, 4, j.m_value.number_integer);
-                    }
-                    else if (j.m_value.number_integer >= (std::numeric_limits<int64_t>::min)() and j.m_value.number_integer <= (std::numeric_limits<int64_t>::max)())
-                    {
-                        // int 64
-                        v.push_back(0xd3);
-                        add_to_vector(v, 8, j.m_value.number_integer);
-                    }
-                }
-                break;
-            }
+        // delegate the call to get_ptr<>()
+        auto ptr = obj.template get_ptr<typename std::add_pointer<ReferenceType>::type>();
 
-            case value_t::number_unsigned:
-            {
-                if (j.m_value.number_unsigned < 128)
-                {
-                    // positive fixnum
-                    add_to_vector(v, 1, j.m_value.number_unsigned);
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
-                {
-                    // uint 8
-                    v.push_back(0xcc);
-                    add_to_vector(v, 1, j.m_value.number_unsigned);
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
-                {
-                    // uint 16
-                    v.push_back(0xcd);
-                    add_to_vector(v, 2, j.m_value.number_unsigned);
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
-                {
-                    // uint 32
-                    v.push_back(0xce);
-                    add_to_vector(v, 4, j.m_value.number_unsigned);
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)())
-                {
-                    // uint 64
-                    v.push_back(0xcf);
-                    add_to_vector(v, 8, j.m_value.number_unsigned);
-                }
-                break;
-            }
+        if (JSON_LIKELY(ptr != nullptr))
+        {
+            return *ptr;
+        }
 
-            case value_t::number_float:
-            {
-                // float 64
-                v.push_back(0xcb);
-                const auto* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float));
-                for (size_t i = 0; i < 8; ++i)
-                {
-                    v.push_back(helper[7 - i]);
-                }
-                break;
-            }
+        JSON_THROW(type_error::create(303, "incompatible ReferenceType for get_ref, actual type is " + std::string(obj.type_name())));
+    }
 
-            case value_t::string:
-            {
-                const auto N = j.m_value.string->size();
-                if (N <= 31)
-                {
-                    // fixstr
-                    v.push_back(static_cast<uint8_t>(0xa0 | N));
-                }
-                else if (N <= 255)
-                {
-                    // str 8
-                    v.push_back(0xd9);
-                    add_to_vector(v, 1, N);
-                }
-                else if (N <= 65535)
-                {
-                    // str 16
-                    v.push_back(0xda);
-                    add_to_vector(v, 2, N);
-                }
-                else if (N <= 4294967295)
-                {
-                    // str 32
-                    v.push_back(0xdb);
-                    add_to_vector(v, 4, N);
-                }
+  public:
+    /// @name value access
+    /// Direct access to the stored value of a JSON value.
+    /// @{
 
-                // append string
-                std::copy(j.m_value.string->begin(), j.m_value.string->end(),
-                          std::back_inserter(v));
-                break;
-            }
+    /*!
+    @brief get special-case overload
 
-            case value_t::array:
-            {
-                const auto N = j.m_value.array->size();
-                if (N <= 15)
-                {
-                    // fixarray
-                    v.push_back(static_cast<uint8_t>(0x90 | N));
-                }
-                else if (N <= 0xffff)
-                {
-                    // array 16
-                    v.push_back(0xdc);
-                    add_to_vector(v, 2, N);
-                }
-                else if (N <= 0xffffffff)
-                {
-                    // array 32
-                    v.push_back(0xdd);
-                    add_to_vector(v, 4, N);
-                }
+    This overloads avoids a lot of template boilerplate, it can be seen as the
+    identity method
 
-                // append each element
-                for (const auto& el : *j.m_value.array)
-                {
-                    to_msgpack_internal(el, v);
-                }
-                break;
-            }
+    @tparam BasicJsonType == @ref basic_json
 
-            case value_t::object:
-            {
-                const auto N = j.m_value.object->size();
-                if (N <= 15)
-                {
-                    // fixmap
-                    v.push_back(static_cast<uint8_t>(0x80 | (N & 0xf)));
-                }
-                else if (N <= 65535)
-                {
-                    // map 16
-                    v.push_back(0xde);
-                    add_to_vector(v, 2, N);
-                }
-                else if (N <= 4294967295)
-                {
-                    // map 32
-                    v.push_back(0xdf);
-                    add_to_vector(v, 4, N);
-                }
+    @return a copy of *this
 
-                // append each element
-                for (const auto& el : *j.m_value.object)
-                {
-                    to_msgpack_internal(el.first, v);
-                    to_msgpack_internal(el.second, v);
-                }
-                break;
-            }
+    @complexity Constant.
 
-            default:
-            {
-                break;
-            }
-        }
+    @since version 2.1.0
+    */
+    template<typename BasicJsonType, detail::enable_if_t<
+                 std::is_same<typename std::remove_const<BasicJsonType>::type, basic_json_t>::value,
+                 int> = 0>
+    basic_json get() const
+    {
+        return *this;
     }
 
     /*!
-    @brief create a CBOR serialization of a given JSON value
+    @brief get a value (explicit)
 
-    This is a straightforward implementation of the CBOR specification.
+    Explicit type conversion between the JSON value and a compatible value
+    which is [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible)
+    and [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible).
+    The value is converted by calling the @ref json_serializer<ValueType>
+    `from_json()` method.
 
-    @param[in] j  JSON value to serialize
-    @param[in,out] v  byte vector to write the serialization to
+    The function is equivalent to executing
+    @code {.cpp}
+    ValueType ret;
+    JSONSerializer<ValueType>::from_json(*this, ret);
+    return ret;
+    @endcode
 
-    @sa https://tools.ietf.org/html/rfc7049
-    */
-    static void to_cbor_internal(const basic_json& j, std::vector<uint8_t>& v)
-    {
-        switch (j.type())
-        {
-            case value_t::null:
-            {
-                v.push_back(0xf6);
-                break;
-            }
-
-            case value_t::boolean:
-            {
-                v.push_back(j.m_value.boolean ? 0xf5 : 0xf4);
-                break;
-            }
-
-            case value_t::number_integer:
-            {
-                if (j.m_value.number_integer >= 0)
-                {
-                    // CBOR does not differentiate between positive signed
-                    // integers and unsigned integers. Therefore, we used the
-                    // code from the value_t::number_unsigned case here.
-                    if (j.m_value.number_integer <= 0x17)
-                    {
-                        add_to_vector(v, 1, j.m_value.number_integer);
-                    }
-                    else if (j.m_value.number_integer <= (std::numeric_limits<uint8_t>::max)())
-                    {
-                        v.push_back(0x18);
-                        // one-byte uint8_t
-                        add_to_vector(v, 1, j.m_value.number_integer);
-                    }
-                    else if (j.m_value.number_integer <= (std::numeric_limits<uint16_t>::max)())
-                    {
-                        v.push_back(0x19);
-                        // two-byte uint16_t
-                        add_to_vector(v, 2, j.m_value.number_integer);
-                    }
-                    else if (j.m_value.number_integer <= (std::numeric_limits<uint32_t>::max)())
-                    {
-                        v.push_back(0x1a);
-                        // four-byte uint32_t
-                        add_to_vector(v, 4, j.m_value.number_integer);
-                    }
-                    else
-                    {
-                        v.push_back(0x1b);
-                        // eight-byte uint64_t
-                        add_to_vector(v, 8, j.m_value.number_integer);
-                    }
-                }
-                else
-                {
-                    // The conversions below encode the sign in the first
-                    // byte, and the value is converted to a positive number.
-                    const auto positive_number = -1 - j.m_value.number_integer;
-                    if (j.m_value.number_integer >= -24)
-                    {
-                        v.push_back(static_cast<uint8_t>(0x20 + positive_number));
-                    }
-                    else if (positive_number <= (std::numeric_limits<uint8_t>::max)())
-                    {
-                        // int 8
-                        v.push_back(0x38);
-                        add_to_vector(v, 1, positive_number);
-                    }
-                    else if (positive_number <= (std::numeric_limits<uint16_t>::max)())
-                    {
-                        // int 16
-                        v.push_back(0x39);
-                        add_to_vector(v, 2, positive_number);
-                    }
-                    else if (positive_number <= (std::numeric_limits<uint32_t>::max)())
-                    {
-                        // int 32
-                        v.push_back(0x3a);
-                        add_to_vector(v, 4, positive_number);
-                    }
-                    else
-                    {
-                        // int 64
-                        v.push_back(0x3b);
-                        add_to_vector(v, 8, positive_number);
-                    }
-                }
-                break;
-            }
-
-            case value_t::number_unsigned:
-            {
-                if (j.m_value.number_unsigned <= 0x17)
-                {
-                    v.push_back(static_cast<uint8_t>(j.m_value.number_unsigned));
-                }
-                else if (j.m_value.number_unsigned <= 0xff)
-                {
-                    v.push_back(0x18);
-                    // one-byte uint8_t
-                    add_to_vector(v, 1, j.m_value.number_unsigned);
-                }
-                else if (j.m_value.number_unsigned <= 0xffff)
-                {
-                    v.push_back(0x19);
-                    // two-byte uint16_t
-                    add_to_vector(v, 2, j.m_value.number_unsigned);
-                }
-                else if (j.m_value.number_unsigned <= 0xffffffff)
-                {
-                    v.push_back(0x1a);
-                    // four-byte uint32_t
-                    add_to_vector(v, 4, j.m_value.number_unsigned);
-                }
-                else if (j.m_value.number_unsigned <= 0xffffffffffffffff)
-                {
-                    v.push_back(0x1b);
-                    // eight-byte uint64_t
-                    add_to_vector(v, 8, j.m_value.number_unsigned);
-                }
-                break;
-            }
+    This overloads is chosen if:
+    - @a ValueType is not @ref basic_json,
+    - @ref json_serializer<ValueType> has a `from_json()` method of the form
+      `void from_json(const basic_json&, ValueType&)`, and
+    - @ref json_serializer<ValueType> does not have a `from_json()` method of
+      the form `ValueType from_json(const basic_json&)`
 
-            case value_t::number_float:
-            {
-                // Double-Precision Float
-                v.push_back(0xfb);
-                const auto* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float));
-                for (size_t i = 0; i < 8; ++i)
-                {
-                    v.push_back(helper[7 - i]);
-                }
-                break;
-            }
+    @tparam ValueTypeCV the provided value type
+    @tparam ValueType the returned value type
 
-            case value_t::string:
-            {
-                const auto N = j.m_value.string->size();
-                if (N <= 0x17)
-                {
-                    v.push_back(static_cast<uint8_t>(0x60 + N));  // 1 byte for string + size
-                }
-                else if (N <= 0xff)
-                {
-                    v.push_back(0x78);  // one-byte uint8_t for N
-                    add_to_vector(v, 1, N);
-                }
-                else if (N <= 0xffff)
-                {
-                    v.push_back(0x79);  // two-byte uint16_t for N
-                    add_to_vector(v, 2, N);
-                }
-                else if (N <= 0xffffffff)
-                {
-                    v.push_back(0x7a); // four-byte uint32_t for N
-                    add_to_vector(v, 4, N);
-                }
-                // LCOV_EXCL_START
-                else if (N <= 0xffffffffffffffff)
-                {
-                    v.push_back(0x7b);  // eight-byte uint64_t for N
-                    add_to_vector(v, 8, N);
-                }
-                // LCOV_EXCL_STOP
+    @return copy of the JSON value, converted to @a ValueType
 
-                // append string
-                std::copy(j.m_value.string->begin(), j.m_value.string->end(),
-                          std::back_inserter(v));
-                break;
-            }
+    @throw what @ref json_serializer<ValueType> `from_json()` method throws
 
-            case value_t::array:
-            {
-                const auto N = j.m_value.array->size();
-                if (N <= 0x17)
-                {
-                    v.push_back(static_cast<uint8_t>(0x80 + N));  // 1 byte for array + size
-                }
-                else if (N <= 0xff)
-                {
-                    v.push_back(0x98);  // one-byte uint8_t for N
-                    add_to_vector(v, 1, N);
-                }
-                else if (N <= 0xffff)
-                {
-                    v.push_back(0x99);  // two-byte uint16_t for N
-                    add_to_vector(v, 2, N);
-                }
-                else if (N <= 0xffffffff)
-                {
-                    v.push_back(0x9a);  // four-byte uint32_t for N
-                    add_to_vector(v, 4, N);
-                }
-                // LCOV_EXCL_START
-                else if (N <= 0xffffffffffffffff)
-                {
-                    v.push_back(0x9b);  // eight-byte uint64_t for N
-                    add_to_vector(v, 8, N);
-                }
-                // LCOV_EXCL_STOP
+    @liveexample{The example below shows several conversions from JSON values
+    to other types. There a few things to note: (1) Floating-point numbers can
+    be converted to integers\, (2) A JSON array can be converted to a standard
+    `std::vector<short>`\, (3) A JSON object can be converted to C++
+    associative containers such as `std::unordered_map<std::string\,
+    json>`.,get__ValueType_const}
 
-                // append each element
-                for (const auto& el : *j.m_value.array)
-                {
-                    to_cbor_internal(el, v);
-                }
-                break;
-            }
+    @since version 2.1.0
+    */
+    template<typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>,
+             detail::enable_if_t <
+                 not std::is_same<basic_json_t, ValueType>::value and
+                 detail::has_from_json<basic_json_t, ValueType>::value and
+                 not detail::has_non_default_from_json<basic_json_t, ValueType>::value,
+                 int> = 0>
+    ValueType get() const noexcept(noexcept(
+                                       JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), std::declval<ValueType&>())))
+    {
+        // we cannot static_assert on ValueTypeCV being non-const, because
+        // there is support for get<const basic_json_t>(), which is why we
+        // still need the uncvref
+        static_assert(not std::is_reference<ValueTypeCV>::value,
+                      "get() cannot be used with reference types, you might want to use get_ref()");
+        static_assert(std::is_default_constructible<ValueType>::value,
+                      "types must be DefaultConstructible when used with get()");
 
-            case value_t::object:
-            {
-                const auto N = j.m_value.object->size();
-                if (N <= 0x17)
-                {
-                    v.push_back(static_cast<uint8_t>(0xa0 + N));  // 1 byte for object + size
-                }
-                else if (N <= 0xff)
-                {
-                    v.push_back(0xb8);
-                    add_to_vector(v, 1, N);  // one-byte uint8_t for N
-                }
-                else if (N <= 0xffff)
-                {
-                    v.push_back(0xb9);
-                    add_to_vector(v, 2, N);  // two-byte uint16_t for N
-                }
-                else if (N <= 0xffffffff)
-                {
-                    v.push_back(0xba);
-                    add_to_vector(v, 4, N);  // four-byte uint32_t for N
-                }
-                // LCOV_EXCL_START
-                else if (N <= 0xffffffffffffffff)
-                {
-                    v.push_back(0xbb);
-                    add_to_vector(v, 8, N);  // eight-byte uint64_t for N
-                }
-                // LCOV_EXCL_STOP
+        ValueType ret;
+        JSONSerializer<ValueType>::from_json(*this, ret);
+        return ret;
+    }
 
-                // append each element
-                for (const auto& el : *j.m_value.object)
-                {
-                    to_cbor_internal(el.first, v);
-                    to_cbor_internal(el.second, v);
-                }
-                break;
-            }
+    /*!
+    @brief get a value (explicit); special case
 
-            default:
-            {
-                break;
-            }
-        }
-    }
+    Explicit type conversion between the JSON value and a compatible value
+    which is **not** [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible)
+    and **not** [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible).
+    The value is converted by calling the @ref json_serializer<ValueType>
+    `from_json()` method.
 
+    The function is equivalent to executing
+    @code {.cpp}
+    return JSONSerializer<ValueTypeCV>::from_json(*this);
+    @endcode
 
-    /*
-    @brief checks if given lengths do not exceed the size of a given vector
+    This overloads is chosen if:
+    - @a ValueType is not @ref basic_json and
+    - @ref json_serializer<ValueType> has a `from_json()` method of the form
+      `ValueType from_json(const basic_json&)`
 
-    To secure the access to the byte vector during CBOR/MessagePack
-    deserialization, bytes are copied from the vector into buffers. This
-    function checks if the number of bytes to copy (@a len) does not exceed
-    the size @s size of the vector. Additionally, an @a offset is given from
-    where to start reading the bytes.
+    @note If @ref json_serializer<ValueType> has both overloads of
+    `from_json()`, this one is chosen.
 
-    This function checks whether reading the bytes is safe; that is, offset is
-    a valid index in the vector, offset+len
+    @tparam ValueTypeCV the provided value type
+    @tparam ValueType the returned value type
 
-    @param[in] size    size of the byte vector
-    @param[in] len     number of bytes to read
-    @param[in] offset  offset where to start reading
+    @return copy of the JSON value, converted to @a ValueType
 
-    vec:  x x x x x X X X X X
-          ^         ^         ^
-          0         offset    len
+    @throw what @ref json_serializer<ValueType> `from_json()` method throws
 
-    @throws out_of_range if `len > v.size()`
+    @since version 2.1.0
     */
-    static void check_length(const size_t size, const size_t len, const size_t offset)
+    template<typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>,
+             detail::enable_if_t<not std::is_same<basic_json_t, ValueType>::value and
+                                 detail::has_non_default_from_json<basic_json_t, ValueType>::value,
+                                 int> = 0>
+    ValueType get() const noexcept(noexcept(
+                                       JSONSerializer<ValueTypeCV>::from_json(std::declval<const basic_json_t&>())))
     {
-        // simple case: requested length is greater than the vector's length
-        if (len > size or offset > size)
-        {
-            JSON_THROW(parse_error::create(110, offset + 1, "cannot read " + std::to_string(len) + " bytes from vector"));
-        }
-
-        // second case: adding offset would result in overflow
-        if ((size > ((std::numeric_limits<size_t>::max)() - offset)))
-        {
-            JSON_THROW(parse_error::create(110, offset + 1, "cannot read " + std::to_string(len) + " bytes from vector"));
-        }
-
-        // last case: reading past the end of the vector
-        if (len + offset > size)
-        {
-            JSON_THROW(parse_error::create(110, offset + 1, "cannot read " + std::to_string(len) + " bytes from vector"));
-        }
+        static_assert(not std::is_reference<ValueTypeCV>::value,
+                      "get() cannot be used with reference types, you might want to use get_ref()");
+        return JSONSerializer<ValueTypeCV>::from_json(*this);
     }
 
     /*!
-    @brief check if the next byte belongs to a string
-
-    While parsing a map, the keys must be strings. This function checks if the
-    current byte is one of the start bytes for a string in MessagePack:
-
-    - 0xa0 - 0xbf: fixstr
-    - 0xd9: str 8
-    - 0xda: str 16
-    - 0xdb: str 32
-
-    @param[in] v  MessagePack serialization
-    @param[in] idx  byte index in @a v to check for a string
+    @brief get a pointer value (explicit)
 
-    @throw parse_error.113 if `v[idx]` does not belong to a string
-    */
-    static void msgpack_expect_string(const std::vector<uint8_t>& v, size_t idx)
-    {
-        check_length(v.size(), 1, idx);
+    Explicit pointer access to the internally stored JSON value. No copies are
+    made.
 
-        const auto byte = v[idx];
-        if ((byte >= 0xa0 and byte <= 0xbf) or (byte >= 0xd9 and byte <= 0xdb))
-        {
-            return;
-        }
+    @warning The pointer becomes invalid if the underlying JSON object
+    changes.
 
-        std::stringstream ss;
-        ss << std::hex << static_cast<int>(v[idx]);
-        JSON_THROW(parse_error::create(113, idx + 1, "expected a MessagePack string; last byte: 0x" + ss.str()));
-    }
+    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
+    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
+    @ref number_unsigned_t, or @ref number_float_t.
 
-    /*!
-    @brief check if the next byte belongs to a string
+    @return pointer to the internally stored JSON value if the requested
+    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
 
-    While parsing a map, the keys must be strings. This function checks if the
-    current byte is one of the start bytes for a string in CBOR:
+    @complexity Constant.
 
-    - 0x60 - 0x77: fixed length
-    - 0x78 - 0x7b: variable length
-    - 0x7f: indefinity length
+    @liveexample{The example below shows how pointers to internal values of a
+    JSON value can be requested. Note that no type conversions are made and a
+    `nullptr` is returned if the value and the requested pointer type does not
+    match.,get__PointerType}
 
-    @param[in] v  CBOR serialization
-    @param[in] idx  byte index in @a v to check for a string
+    @sa @ref get_ptr() for explicit pointer-member access
 
-    @throw parse_error.113 if `v[idx]` does not belong to a string
+    @since version 1.0.0
     */
-    static void cbor_expect_string(const std::vector<uint8_t>& v, size_t idx)
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value, int>::type = 0>
+    PointerType get() noexcept
     {
-        check_length(v.size(), 1, idx);
-
-        const auto byte = v[idx];
-        if ((byte >= 0x60 and byte <= 0x7b) or byte == 0x7f)
-        {
-            return;
-        }
-
-        std::stringstream ss;
-        ss << std::hex << static_cast<int>(v[idx]);
-        JSON_THROW(parse_error::create(113, idx + 1, "expected a CBOR string; last byte: 0x" + ss.str()));
+        // delegate the call to get_ptr
+        return get_ptr<PointerType>();
     }
 
     /*!
-    @brief create a JSON value from a given MessagePack vector
-
-    @param[in] v  MessagePack serialization
-    @param[in] idx  byte index to start reading from @a v
-
-    @return deserialized JSON value
-
-    @throw parse_error.110 if the given vector ends prematurely
-    @throw parse_error.112 if unsupported features from MessagePack were
-    used in the given vector @a v or if the input is not valid MessagePack
-    @throw parse_error.113 if a string was expected as map key, but not found
-
-    @sa https://github.com/msgpack/msgpack/blob/master/spec.md
+    @brief get a pointer value (explicit)
+    @copydoc get()
     */
-    static basic_json from_msgpack_internal(const std::vector<uint8_t>& v, size_t& idx)
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value, int>::type = 0>
+    constexpr const PointerType get() const noexcept
     {
-        // store and increment index
-        const size_t current_idx = idx++;
-
-        // make sure reading 1 byte is safe
-        check_length(v.size(), 1, current_idx);
+        // delegate the call to get_ptr
+        return get_ptr<PointerType>();
+    }
 
-        if (v[current_idx] <= 0xbf)
-        {
-            if (v[current_idx] <= 0x7f) // positive fixint
-            {
-                return v[current_idx];
-            }
-            if (v[current_idx] <= 0x8f) // fixmap
-            {
-                basic_json result = value_t::object;
-                const size_t len = v[current_idx] & 0x0f;
-                for (size_t i = 0; i < len; ++i)
-                {
-                    msgpack_expect_string(v, idx);
-                    std::string key = from_msgpack_internal(v, idx);
-                    result[key] = from_msgpack_internal(v, idx);
-                }
-                return result;
-            }
-            else if (v[current_idx] <= 0x9f) // fixarray
-            {
-                basic_json result = value_t::array;
-                const size_t len = v[current_idx] & 0x0f;
-                for (size_t i = 0; i < len; ++i)
-                {
-                    result.push_back(from_msgpack_internal(v, idx));
-                }
-                return result;
-            }
-            else // fixstr
-            {
-                const size_t len = v[current_idx] & 0x1f;
-                const size_t offset = current_idx + 1;
-                idx += len; // skip content bytes
-                check_length(v.size(), len, offset);
-                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
-            }
-        }
-        else if (v[current_idx] >= 0xe0) // negative fixint
-        {
-            return static_cast<int8_t>(v[current_idx]);
-        }
-        else
-        {
-            switch (v[current_idx])
-            {
-                case 0xc0: // nil
-                {
-                    return value_t::null;
-                }
+    /*!
+    @brief get a pointer value (implicit)
 
-                case 0xc2: // false
-                {
-                    return false;
-                }
+    Implicit pointer access to the internally stored JSON value. No copies are
+    made.
 
-                case 0xc3: // true
-                {
-                    return true;
-                }
+    @warning Writing data to the pointee of the result yields an undefined
+    state.
 
-                case 0xca: // float 32
-                {
-                    // copy bytes in reverse order into the double variable
-                    float res;
-                    check_length(v.size(), sizeof(float), current_idx + 1);
-                    for (size_t byte = 0; byte < sizeof(float); ++byte)
-                    {
-                        reinterpret_cast<uint8_t*>(&res)[sizeof(float) - byte - 1] = v[current_idx + 1 + byte];
-                    }
-                    idx += sizeof(float); // skip content bytes
-                    return res;
-                }
+    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
+    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
+    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
+    assertion.
 
-                case 0xcb: // float 64
-                {
-                    // copy bytes in reverse order into the double variable
-                    double res;
-                    check_length(v.size(), sizeof(double), current_idx + 1);
-                    for (size_t byte = 0; byte < sizeof(double); ++byte)
-                    {
-                        reinterpret_cast<uint8_t*>(&res)[sizeof(double) - byte - 1] = v[current_idx + 1 + byte];
-                    }
-                    idx += sizeof(double); // skip content bytes
-                    return res;
-                }
+    @return pointer to the internally stored JSON value if the requested
+    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
 
-                case 0xcc: // uint 8
-                {
-                    idx += 1; // skip content byte
-                    return get_from_vector<uint8_t>(v, current_idx);
-                }
+    @complexity Constant.
 
-                case 0xcd: // uint 16
-                {
-                    idx += 2; // skip 2 content bytes
-                    return get_from_vector<uint16_t>(v, current_idx);
-                }
+    @liveexample{The example below shows how pointers to internal values of a
+    JSON value can be requested. Note that no type conversions are made and a
+    `nullptr` is returned if the value and the requested pointer type does not
+    match.,get_ptr}
 
-                case 0xce: // uint 32
-                {
-                    idx += 4; // skip 4 content bytes
-                    return get_from_vector<uint32_t>(v, current_idx);
-                }
+    @since version 1.0.0
+    */
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value, int>::type = 0>
+    PointerType get_ptr() noexcept
+    {
+        // get the type of the PointerType (remove pointer and const)
+        using pointee_t = typename std::remove_const<typename
+                          std::remove_pointer<typename
+                          std::remove_const<PointerType>::type>::type>::type;
+        // make sure the type matches the allowed types
+        static_assert(
+            std::is_same<object_t, pointee_t>::value
+            or std::is_same<array_t, pointee_t>::value
+            or std::is_same<string_t, pointee_t>::value
+            or std::is_same<boolean_t, pointee_t>::value
+            or std::is_same<number_integer_t, pointee_t>::value
+            or std::is_same<number_unsigned_t, pointee_t>::value
+            or std::is_same<number_float_t, pointee_t>::value
+            , "incompatible pointer type");
 
-                case 0xcf: // uint 64
-                {
-                    idx += 8; // skip 8 content bytes
-                    return get_from_vector<uint64_t>(v, current_idx);
-                }
+        // delegate the call to get_impl_ptr<>()
+        return get_impl_ptr(static_cast<PointerType>(nullptr));
+    }
 
-                case 0xd0: // int 8
-                {
-                    idx += 1; // skip content byte
-                    return get_from_vector<int8_t>(v, current_idx);
-                }
+    /*!
+    @brief get a pointer value (implicit)
+    @copydoc get_ptr()
+    */
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value and
+                 std::is_const<typename std::remove_pointer<PointerType>::type>::value, int>::type = 0>
+    constexpr const PointerType get_ptr() const noexcept
+    {
+        // get the type of the PointerType (remove pointer and const)
+        using pointee_t = typename std::remove_const<typename
+                          std::remove_pointer<typename
+                          std::remove_const<PointerType>::type>::type>::type;
+        // make sure the type matches the allowed types
+        static_assert(
+            std::is_same<object_t, pointee_t>::value
+            or std::is_same<array_t, pointee_t>::value
+            or std::is_same<string_t, pointee_t>::value
+            or std::is_same<boolean_t, pointee_t>::value
+            or std::is_same<number_integer_t, pointee_t>::value
+            or std::is_same<number_unsigned_t, pointee_t>::value
+            or std::is_same<number_float_t, pointee_t>::value
+            , "incompatible pointer type");
 
-                case 0xd1: // int 16
-                {
-                    idx += 2; // skip 2 content bytes
-                    return get_from_vector<int16_t>(v, current_idx);
-                }
+        // delegate the call to get_impl_ptr<>() const
+        return get_impl_ptr(static_cast<PointerType>(nullptr));
+    }
 
-                case 0xd2: // int 32
-                {
-                    idx += 4; // skip 4 content bytes
-                    return get_from_vector<int32_t>(v, current_idx);
-                }
+    /*!
+    @brief get a reference value (implicit)
 
-                case 0xd3: // int 64
-                {
-                    idx += 8; // skip 8 content bytes
-                    return get_from_vector<int64_t>(v, current_idx);
-                }
+    Implicit reference access to the internally stored JSON value. No copies
+    are made.
 
-                case 0xd9: // str 8
-                {
-                    const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx));
-                    const size_t offset = current_idx + 2;
-                    idx += len + 1; // skip size byte + content bytes
-                    check_length(v.size(), len, offset);
-                    return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
-                }
+    @warning Writing data to the referee of the result yields an undefined
+    state.
 
-                case 0xda: // str 16
-                {
-                    const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
-                    const size_t offset = current_idx + 3;
-                    idx += len + 2; // skip 2 size bytes + content bytes
-                    check_length(v.size(), len, offset);
-                    return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
-                }
+    @tparam ReferenceType reference type; must be a reference to @ref array_t,
+    @ref object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, or
+    @ref number_float_t. Enforced by static assertion.
 
-                case 0xdb: // str 32
-                {
-                    const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
-                    const size_t offset = current_idx + 5;
-                    idx += len + 4; // skip 4 size bytes + content bytes
-                    check_length(v.size(), len, offset);
-                    return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
-                }
+    @return reference to the internally stored JSON value if the requested
+    reference type @a ReferenceType fits to the JSON value; throws
+    type_error.303 otherwise
 
-                case 0xdc: // array 16
-                {
-                    basic_json result = value_t::array;
-                    const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
-                    idx += 2; // skip 2 size bytes
-                    for (size_t i = 0; i < len; ++i)
-                    {
-                        result.push_back(from_msgpack_internal(v, idx));
-                    }
-                    return result;
-                }
+    @throw type_error.303 in case passed type @a ReferenceType is incompatible
+    with the stored JSON value; see example below
 
-                case 0xdd: // array 32
-                {
-                    basic_json result = value_t::array;
-                    const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
-                    idx += 4; // skip 4 size bytes
-                    for (size_t i = 0; i < len; ++i)
-                    {
-                        result.push_back(from_msgpack_internal(v, idx));
-                    }
-                    return result;
-                }
+    @complexity Constant.
 
-                case 0xde: // map 16
-                {
-                    basic_json result = value_t::object;
-                    const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
-                    idx += 2; // skip 2 size bytes
-                    for (size_t i = 0; i < len; ++i)
-                    {
-                        msgpack_expect_string(v, idx);
-                        std::string key = from_msgpack_internal(v, idx);
-                        result[key] = from_msgpack_internal(v, idx);
-                    }
-                    return result;
-                }
+    @liveexample{The example shows several calls to `get_ref()`.,get_ref}
 
-                case 0xdf: // map 32
-                {
-                    basic_json result = value_t::object;
-                    const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
-                    idx += 4; // skip 4 size bytes
-                    for (size_t i = 0; i < len; ++i)
-                    {
-                        msgpack_expect_string(v, idx);
-                        std::string key = from_msgpack_internal(v, idx);
-                        result[key] = from_msgpack_internal(v, idx);
-                    }
-                    return result;
-                }
+    @since version 1.1.0
+    */
+    template<typename ReferenceType, typename std::enable_if<
+                 std::is_reference<ReferenceType>::value, int>::type = 0>
+    ReferenceType get_ref()
+    {
+        // delegate call to get_ref_impl
+        return get_ref_impl<ReferenceType>(*this);
+    }
 
-                default:
-                {
-                    std::stringstream ss;
-                    ss << std::hex << static_cast<int>(v[current_idx]);
-                    JSON_THROW(parse_error::create(112, current_idx + 1, "error reading MessagePack; last byte: 0x" + ss.str()));
-                }
-            }
-        }
+    /*!
+    @brief get a reference value (implicit)
+    @copydoc get_ref()
+    */
+    template<typename ReferenceType, typename std::enable_if<
+                 std::is_reference<ReferenceType>::value and
+                 std::is_const<typename std::remove_reference<ReferenceType>::type>::value, int>::type = 0>
+    ReferenceType get_ref() const
+    {
+        // delegate call to get_ref_impl
+        return get_ref_impl<ReferenceType>(*this);
     }
 
     /*!
-    @brief create a JSON value from a given CBOR vector
+    @brief get a value (implicit)
 
-    @param[in] v  CBOR serialization
-    @param[in] idx  byte index to start reading from @a v
+    Implicit type conversion between the JSON value and a compatible value.
+    The call is realized by calling @ref get() const.
 
-    @return deserialized JSON value
+    @tparam ValueType non-pointer type compatible to the JSON value, for
+    instance `int` for JSON integer numbers, `bool` for JSON booleans, or
+    `std::vector` types for JSON arrays. The character type of @ref string_t
+    as well as an initializer list of this type is excluded to avoid
+    ambiguities as these types implicitly convert to `std::string`.
 
-    @throw parse_error.110 if the given vector ends prematurely
-    @throw parse_error.112 if unsupported features from CBOR were
-    used in the given vector @a v or if the input is not valid CBOR
-    @throw parse_error.113 if a string was expected as map key, but not found
+    @return copy of the JSON value, converted to type @a ValueType
+
+    @throw type_error.302 in case passed type @a ValueType is incompatible
+    to the JSON value type (e.g., the JSON value is of type boolean, but a
+    string is requested); see example below
+
+    @complexity Linear in the size of the JSON value.
+
+    @liveexample{The example below shows several conversions from JSON values
+    to other types. There a few things to note: (1) Floating-point numbers can
+    be converted to integers\, (2) A JSON array can be converted to a standard
+    `std::vector<short>`\, (3) A JSON object can be converted to C++
+    associative containers such as `std::unordered_map<std::string\,
+    json>`.,operator__ValueType}
 
-    @sa https://tools.ietf.org/html/rfc7049
+    @since version 1.0.0
     */
-    static basic_json from_cbor_internal(const std::vector<uint8_t>& v, size_t& idx)
+    template < typename ValueType, typename std::enable_if <
+                   not std::is_pointer<ValueType>::value and
+                   not std::is_same<ValueType, detail::json_ref<basic_json>>::value and
+                   not std::is_same<ValueType, typename string_t::value_type>::value
+#ifndef _MSC_VER  // fix for issue #167 operator<< ambiguity under VS2015
+                   and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
+#endif
+#if defined(JSON_HAS_CPP_17)
+                   and not std::is_same<ValueType, typename std::string_view>::value
+#endif
+                   , int >::type = 0 >
+    operator ValueType() const
     {
-        // store and increment index
-        const size_t current_idx = idx++;
+        // delegate the call to get<>() const
+        return get<ValueType>();
+    }
 
-        // make sure reading 1 byte is safe
-        check_length(v.size(), 1, current_idx);
+    /// @}
 
-        switch (v[current_idx])
-        {
-            // Integer 0x00..0x17 (0..23)
-            case 0x00:
-            case 0x01:
-            case 0x02:
-            case 0x03:
-            case 0x04:
-            case 0x05:
-            case 0x06:
-            case 0x07:
-            case 0x08:
-            case 0x09:
-            case 0x0a:
-            case 0x0b:
-            case 0x0c:
-            case 0x0d:
-            case 0x0e:
-            case 0x0f:
-            case 0x10:
-            case 0x11:
-            case 0x12:
-            case 0x13:
-            case 0x14:
-            case 0x15:
-            case 0x16:
-            case 0x17:
-            {
-                return v[current_idx];
-            }
 
-            case 0x18: // Unsigned integer (one-byte uint8_t follows)
-            {
-                idx += 1; // skip content byte
-                return get_from_vector<uint8_t>(v, current_idx);
-            }
+    ////////////////////
+    // element access //
+    ////////////////////
 
-            case 0x19: // Unsigned integer (two-byte uint16_t follows)
-            {
-                idx += 2; // skip 2 content bytes
-                return get_from_vector<uint16_t>(v, current_idx);
-            }
+    /// @name element access
+    /// Access to the JSON value.
+    /// @{
 
-            case 0x1a: // Unsigned integer (four-byte uint32_t follows)
-            {
-                idx += 4; // skip 4 content bytes
-                return get_from_vector<uint32_t>(v, current_idx);
-            }
+    /*!
+    @brief access specified array element with bounds checking
 
-            case 0x1b: // Unsigned integer (eight-byte uint64_t follows)
-            {
-                idx += 8; // skip 8 content bytes
-                return get_from_vector<uint64_t>(v, current_idx);
-            }
+    Returns a reference to the element at specified location @a idx, with
+    bounds checking.
 
-            // Negative integer -1-0x00..-1-0x17 (-1..-24)
-            case 0x20:
-            case 0x21:
-            case 0x22:
-            case 0x23:
-            case 0x24:
-            case 0x25:
-            case 0x26:
-            case 0x27:
-            case 0x28:
-            case 0x29:
-            case 0x2a:
-            case 0x2b:
-            case 0x2c:
-            case 0x2d:
-            case 0x2e:
-            case 0x2f:
-            case 0x30:
-            case 0x31:
-            case 0x32:
-            case 0x33:
-            case 0x34:
-            case 0x35:
-            case 0x36:
-            case 0x37:
-            {
-                return static_cast<int8_t>(0x20 - 1 - v[current_idx]);
-            }
+    @param[in] idx  index of the element to access
 
-            case 0x38: // Negative integer (one-byte uint8_t follows)
-            {
-                idx += 1; // skip content byte
-                // must be uint8_t !
-                return static_cast<number_integer_t>(-1) - get_from_vector<uint8_t>(v, current_idx);
-            }
+    @return reference to the element at index @a idx
 
-            case 0x39: // Negative integer -1-n (two-byte uint16_t follows)
-            {
-                idx += 2; // skip 2 content bytes
-                return static_cast<number_integer_t>(-1) - get_from_vector<uint16_t>(v, current_idx);
-            }
+    @throw type_error.304 if the JSON value is not an array; in this case,
+    calling `at` with an index makes no sense. See example below.
+    @throw out_of_range.401 if the index @a idx is out of range of the array;
+    that is, `idx >= size()`. See example below.
 
-            case 0x3a: // Negative integer -1-n (four-byte uint32_t follows)
-            {
-                idx += 4; // skip 4 content bytes
-                return static_cast<number_integer_t>(-1) - get_from_vector<uint32_t>(v, current_idx);
-            }
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-            case 0x3b: // Negative integer -1-n (eight-byte uint64_t follows)
-            {
-                idx += 8; // skip 8 content bytes
-                return static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(get_from_vector<uint64_t>(v, current_idx));
-            }
+    @complexity Constant.
 
-            // UTF-8 string (0x00..0x17 bytes follow)
-            case 0x60:
-            case 0x61:
-            case 0x62:
-            case 0x63:
-            case 0x64:
-            case 0x65:
-            case 0x66:
-            case 0x67:
-            case 0x68:
-            case 0x69:
-            case 0x6a:
-            case 0x6b:
-            case 0x6c:
-            case 0x6d:
-            case 0x6e:
-            case 0x6f:
-            case 0x70:
-            case 0x71:
-            case 0x72:
-            case 0x73:
-            case 0x74:
-            case 0x75:
-            case 0x76:
-            case 0x77:
-            {
-                const auto len = static_cast<size_t>(v[current_idx] - 0x60);
-                const size_t offset = current_idx + 1;
-                idx += len; // skip content bytes
-                check_length(v.size(), len, offset);
-                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
-            }
+    @since version 1.0.0
 
-            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
+    @liveexample{The example below shows how array elements can be read and
+    written using `at()`. It also demonstrates the different exceptions that
+    can be thrown.,at__size_type}
+    */
+    reference at(size_type idx)
+    {
+        // at only works for arrays
+        if (JSON_LIKELY(is_array()))
+        {
+            JSON_TRY
             {
-                const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx));
-                const size_t offset = current_idx + 2;
-                idx += len + 1; // skip size byte + content bytes
-                check_length(v.size(), len, offset);
-                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+                return m_value.array->at(idx);
             }
-
-            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
+            JSON_CATCH (std::out_of_range&)
             {
-                const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
-                const size_t offset = current_idx + 3;
-                idx += len + 2; // skip 2 size bytes + content bytes
-                check_length(v.size(), len, offset);
-                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
+                // create better exception explanation
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
             }
+        }
+        else
+        {
+            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
+        }
+    }
 
-            case 0x7a: // UTF-8 string (four-byte uint32_t for n follow)
-            {
-                const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
-                const size_t offset = current_idx + 5;
-                idx += len + 4; // skip 4 size bytes + content bytes
-                check_length(v.size(), len, offset);
-                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
-            }
+    /*!
+    @brief access specified array element with bounds checking
 
-            case 0x7b: // UTF-8 string (eight-byte uint64_t for n follow)
-            {
-                const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx));
-                const size_t offset = current_idx + 9;
-                idx += len + 8; // skip 8 size bytes + content bytes
-                check_length(v.size(), len, offset);
-                return std::string(reinterpret_cast<const char*>(v.data()) + offset, len);
-            }
+    Returns a const reference to the element at specified location @a idx,
+    with bounds checking.
 
-            case 0x7f: // UTF-8 string (indefinite length)
-            {
-                std::string result;
-                while (static_cast<void>(check_length(v.size(), 1, idx)), v[idx] != 0xff)
-                {
-                    string_t s = from_cbor_internal(v, idx);
-                    result += s;
-                }
-                // skip break byte (0xFF)
-                idx += 1;
-                return result;
-            }
+    @param[in] idx  index of the element to access
 
-            // array (0x00..0x17 data items follow)
-            case 0x80:
-            case 0x81:
-            case 0x82:
-            case 0x83:
-            case 0x84:
-            case 0x85:
-            case 0x86:
-            case 0x87:
-            case 0x88:
-            case 0x89:
-            case 0x8a:
-            case 0x8b:
-            case 0x8c:
-            case 0x8d:
-            case 0x8e:
-            case 0x8f:
-            case 0x90:
-            case 0x91:
-            case 0x92:
-            case 0x93:
-            case 0x94:
-            case 0x95:
-            case 0x96:
-            case 0x97:
-            {
-                basic_json result = value_t::array;
-                const auto len = static_cast<size_t>(v[current_idx] - 0x80);
-                for (size_t i = 0; i < len; ++i)
-                {
-                    result.push_back(from_cbor_internal(v, idx));
-                }
-                return result;
-            }
+    @return const reference to the element at index @a idx
 
-            case 0x98: // array (one-byte uint8_t for n follows)
-            {
-                basic_json result = value_t::array;
-                const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx));
-                idx += 1; // skip 1 size byte
-                for (size_t i = 0; i < len; ++i)
-                {
-                    result.push_back(from_cbor_internal(v, idx));
-                }
-                return result;
-            }
+    @throw type_error.304 if the JSON value is not an array; in this case,
+    calling `at` with an index makes no sense. See example below.
+    @throw out_of_range.401 if the index @a idx is out of range of the array;
+    that is, `idx >= size()`. See example below.
 
-            case 0x99: // array (two-byte uint16_t for n follow)
-            {
-                basic_json result = value_t::array;
-                const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
-                idx += 2; // skip 4 size bytes
-                for (size_t i = 0; i < len; ++i)
-                {
-                    result.push_back(from_cbor_internal(v, idx));
-                }
-                return result;
-            }
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-            case 0x9a: // array (four-byte uint32_t for n follow)
-            {
-                basic_json result = value_t::array;
-                const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
-                idx += 4; // skip 4 size bytes
-                for (size_t i = 0; i < len; ++i)
-                {
-                    result.push_back(from_cbor_internal(v, idx));
-                }
-                return result;
-            }
+    @complexity Constant.
 
-            case 0x9b: // array (eight-byte uint64_t for n follow)
-            {
-                basic_json result = value_t::array;
-                const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx));
-                idx += 8; // skip 8 size bytes
-                for (size_t i = 0; i < len; ++i)
-                {
-                    result.push_back(from_cbor_internal(v, idx));
-                }
-                return result;
-            }
+    @since version 1.0.0
 
-            case 0x9f: // array (indefinite length)
+    @liveexample{The example below shows how array elements can be read using
+    `at()`. It also demonstrates the different exceptions that can be thrown.,
+    at__size_type_const}
+    */
+    const_reference at(size_type idx) const
+    {
+        // at only works for arrays
+        if (JSON_LIKELY(is_array()))
+        {
+            JSON_TRY
             {
-                basic_json result = value_t::array;
-                while (static_cast<void>(check_length(v.size(), 1, idx)), v[idx] != 0xff)
-                {
-                    result.push_back(from_cbor_internal(v, idx));
-                }
-                // skip break byte (0xFF)
-                idx += 1;
-                return result;
-            }
-
-            // map (0x00..0x17 pairs of data items follow)
-            case 0xa0:
-            case 0xa1:
-            case 0xa2:
-            case 0xa3:
-            case 0xa4:
-            case 0xa5:
-            case 0xa6:
-            case 0xa7:
-            case 0xa8:
-            case 0xa9:
-            case 0xaa:
-            case 0xab:
-            case 0xac:
-            case 0xad:
-            case 0xae:
-            case 0xaf:
-            case 0xb0:
-            case 0xb1:
-            case 0xb2:
-            case 0xb3:
-            case 0xb4:
-            case 0xb5:
-            case 0xb6:
-            case 0xb7:
-            {
-                basic_json result = value_t::object;
-                const auto len = static_cast<size_t>(v[current_idx] - 0xa0);
-                for (size_t i = 0; i < len; ++i)
-                {
-                    cbor_expect_string(v, idx);
-                    std::string key = from_cbor_internal(v, idx);
-                    result[key] = from_cbor_internal(v, idx);
-                }
-                return result;
+                return m_value.array->at(idx);
             }
-
-            case 0xb8: // map (one-byte uint8_t for n follows)
+            JSON_CATCH (std::out_of_range&)
             {
-                basic_json result = value_t::object;
-                const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx));
-                idx += 1; // skip 1 size byte
-                for (size_t i = 0; i < len; ++i)
-                {
-                    cbor_expect_string(v, idx);
-                    std::string key = from_cbor_internal(v, idx);
-                    result[key] = from_cbor_internal(v, idx);
-                }
-                return result;
+                // create better exception explanation
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
             }
+        }
+        else
+        {
+            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
+        }
+    }
 
-            case 0xb9: // map (two-byte uint16_t for n follow)
-            {
-                basic_json result = value_t::object;
-                const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx));
-                idx += 2; // skip 2 size bytes
-                for (size_t i = 0; i < len; ++i)
-                {
-                    cbor_expect_string(v, idx);
-                    std::string key = from_cbor_internal(v, idx);
-                    result[key] = from_cbor_internal(v, idx);
-                }
-                return result;
-            }
+    /*!
+    @brief access specified object element with bounds checking
 
-            case 0xba: // map (four-byte uint32_t for n follow)
-            {
-                basic_json result = value_t::object;
-                const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx));
-                idx += 4; // skip 4 size bytes
-                for (size_t i = 0; i < len; ++i)
-                {
-                    cbor_expect_string(v, idx);
-                    std::string key = from_cbor_internal(v, idx);
-                    result[key] = from_cbor_internal(v, idx);
-                }
-                return result;
-            }
+    Returns a reference to the element at with specified key @a key, with
+    bounds checking.
 
-            case 0xbb: // map (eight-byte uint64_t for n follow)
-            {
-                basic_json result = value_t::object;
-                const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx));
-                idx += 8; // skip 8 size bytes
-                for (size_t i = 0; i < len; ++i)
-                {
-                    cbor_expect_string(v, idx);
-                    std::string key = from_cbor_internal(v, idx);
-                    result[key] = from_cbor_internal(v, idx);
-                }
-                return result;
-            }
+    @param[in] key  key of the element to access
 
-            case 0xbf: // map (indefinite length)
-            {
-                basic_json result = value_t::object;
-                while (static_cast<void>(check_length(v.size(), 1, idx)), v[idx] != 0xff)
-                {
-                    cbor_expect_string(v, idx);
-                    std::string key = from_cbor_internal(v, idx);
-                    result[key] = from_cbor_internal(v, idx);
-                }
-                // skip break byte (0xFF)
-                idx += 1;
-                return result;
-            }
+    @return reference to the element at key @a key
 
-            case 0xf4: // false
-            {
-                return false;
-            }
+    @throw type_error.304 if the JSON value is not an object; in this case,
+    calling `at` with a key makes no sense. See example below.
+    @throw out_of_range.403 if the key @a key is is not stored in the object;
+    that is, `find(key) == end()`. See example below.
 
-            case 0xf5: // true
-            {
-                return true;
-            }
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-            case 0xf6: // null
-            {
-                return value_t::null;
-            }
+    @complexity Logarithmic in the size of the container.
 
-            case 0xf9: // Half-Precision Float (two-byte IEEE 754)
-            {
-                idx += 2; // skip two content bytes
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
+    @sa @ref value() for access by value with a default value
 
-                // code from RFC 7049, Appendix D, Figure 3:
-                // As half-precision floating-point numbers were only added to
-                // IEEE 754 in 2008, today's programming platforms often still
-                // only have limited support for them. It is very easy to
-                // include at least decoding support for them even without such
-                // support. An example of a small decoder for half-precision
-                // floating-point numbers in the C language is shown in Fig. 3.
-                check_length(v.size(), 2, current_idx + 1);
-                const int half = (v[current_idx + 1] << 8) + v[current_idx + 2];
-                const int exp = (half >> 10) & 0x1f;
-                const int mant = half & 0x3ff;
-                double val;
-                if (exp == 0)
-                {
-                    val = std::ldexp(mant, -24);
-                }
-                else if (exp != 31)
-                {
-                    val = std::ldexp(mant + 1024, exp - 25);
-                }
-                else
-                {
-                    val = mant == 0
-                          ? std::numeric_limits<double>::infinity()
-                          : std::numeric_limits<double>::quiet_NaN();
-                }
-                return (half & 0x8000) != 0 ? -val : val;
-            }
-
-            case 0xfa: // Single-Precision Float (four-byte IEEE 754)
-            {
-                // copy bytes in reverse order into the float variable
-                float res;
-                check_length(v.size(), sizeof(float), current_idx + 1);
-                for (size_t byte = 0; byte < sizeof(float); ++byte)
-                {
-                    reinterpret_cast<uint8_t*>(&res)[sizeof(float) - byte - 1] = v[current_idx + 1 + byte];
-                }
-                idx += sizeof(float); // skip content bytes
-                return res;
-            }
+    @since version 1.0.0
 
-            case 0xfb: // Double-Precision Float (eight-byte IEEE 754)
+    @liveexample{The example below shows how object elements can be read and
+    written using `at()`. It also demonstrates the different exceptions that
+    can be thrown.,at__object_t_key_type}
+    */
+    reference at(const typename object_t::key_type& key)
+    {
+        // at only works for objects
+        if (JSON_LIKELY(is_object()))
+        {
+            JSON_TRY
             {
-                // copy bytes in reverse order into the double variable
-                double res;
-                check_length(v.size(), sizeof(double), current_idx + 1);
-                for (size_t byte = 0; byte < sizeof(double); ++byte)
-                {
-                    reinterpret_cast<uint8_t*>(&res)[sizeof(double) - byte - 1] = v[current_idx + 1 + byte];
-                }
-                idx += sizeof(double); // skip content bytes
-                return res;
+                return m_value.object->at(key);
             }
-
-            default: // anything else (0xFF is handled inside the other types)
+            JSON_CATCH (std::out_of_range&)
             {
-                std::stringstream ss;
-                ss << std::hex << static_cast<int>(v[current_idx]);
-                JSON_THROW(parse_error::create(112, current_idx + 1, "error reading CBOR; last byte: 0x" + ss.str()));
+                // create better exception explanation
+                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
             }
         }
+        else
+        {
+            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
+        }
     }
 
-  public:
     /*!
-    @brief create a MessagePack serialization of a given JSON value
-
-    Serializes a given JSON value @a j to a byte vector using the MessagePack
-    serialization format. MessagePack is a binary serialization format which
-    aims to be more compact than JSON itself, yet more efficient to parse.
-
-    The library uses the following mapping from JSON values types to
-    MessagePack types according to the MessagePack specification:
-
-    JSON value type | value/range                       | MessagePack type | first byte
-    --------------- | --------------------------------- | ---------------- | ----------
-    null            | `null`                            | nil              | 0xc0
-    boolean         | `true`                            | true             | 0xc3
-    boolean         | `false`                           | false            | 0xc2
-    number_integer  | -9223372036854775808..-2147483649 | int64            | 0xd3
-    number_integer  | -2147483648..-32769               | int32            | 0xd2
-    number_integer  | -32768..-129                      | int16            | 0xd1
-    number_integer  | -128..-33                         | int8             | 0xd0
-    number_integer  | -32..-1                           | negative fixint  | 0xe0..0xff
-    number_integer  | 0..127                            | positive fixint  | 0x00..0x7f
-    number_integer  | 128..255                          | uint 8           | 0xcc
-    number_integer  | 256..65535                        | uint 16          | 0xcd
-    number_integer  | 65536..4294967295                 | uint 32          | 0xce
-    number_integer  | 4294967296..18446744073709551615  | uint 64          | 0xcf
-    number_unsigned | 0..127                            | positive fixint  | 0x00..0x7f
-    number_unsigned | 128..255                          | uint 8           | 0xcc
-    number_unsigned | 256..65535                        | uint 16          | 0xcd
-    number_unsigned | 65536..4294967295                 | uint 32          | 0xce
-    number_unsigned | 4294967296..18446744073709551615  | uint 64          | 0xcf
-    number_float    | *any value*                       | float 64         | 0xcb
-    string          | *length*: 0..31                   | fixstr           | 0xa0..0xbf
-    string          | *length*: 32..255                 | str 8            | 0xd9
-    string          | *length*: 256..65535              | str 16           | 0xda
-    string          | *length*: 65536..4294967295       | str 32           | 0xdb
-    array           | *size*: 0..15                     | fixarray         | 0x90..0x9f
-    array           | *size*: 16..65535                 | array 16         | 0xdc
-    array           | *size*: 65536..4294967295         | array 32         | 0xdd
-    object          | *size*: 0..15                     | fix map          | 0x80..0x8f
-    object          | *size*: 16..65535                 | map 16           | 0xde
-    object          | *size*: 65536..4294967295         | map 32           | 0xdf
+    @brief access specified object element with bounds checking
 
-    @note The mapping is **complete** in the sense that any JSON value type
-          can be converted to a MessagePack value.
+    Returns a const reference to the element at with specified key @a key,
+    with bounds checking.
 
-    @note The following values can **not** be converted to a MessagePack value:
-          - strings with more than 4294967295 bytes
-          - arrays with more than 4294967295 elements
-          - objects with more than 4294967295 elements
+    @param[in] key  key of the element to access
 
-    @note The following MessagePack types are not used in the conversion:
-          - bin 8 - bin 32 (0xc4..0xc6)
-          - ext 8 - ext 32 (0xc7..0xc9)
-          - float 32 (0xca)
-          - fixext 1 - fixext 16 (0xd4..0xd8)
+    @return const reference to the element at key @a key
 
-    @note Any MessagePack output created @ref to_msgpack can be successfully
-          parsed by @ref from_msgpack.
+    @throw type_error.304 if the JSON value is not an object; in this case,
+    calling `at` with a key makes no sense. See example below.
+    @throw out_of_range.403 if the key @a key is is not stored in the object;
+    that is, `find(key) == end()`. See example below.
 
-    @param[in] j  JSON value to serialize
-    @return MessagePack serialization as byte vector
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
 
-    @complexity Linear in the size of the JSON value @a j.
+    @complexity Logarithmic in the size of the container.
 
-    @liveexample{The example shows the serialization of a JSON value to a byte
-    vector in MessagePack format.,to_msgpack}
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
+    @sa @ref value() for access by value with a default value
 
-    @sa http://msgpack.org
-    @sa @ref from_msgpack(const std::vector<uint8_t>&, const size_t) for the
-        analogous deserialization
-    @sa @ref to_cbor(const basic_json& for the related CBOR format
+    @since version 1.0.0
 
-    @since version 2.0.9
+    @liveexample{The example below shows how object elements can be read using
+    `at()`. It also demonstrates the different exceptions that can be thrown.,
+    at__object_t_key_type_const}
     */
-    static std::vector<uint8_t> to_msgpack(const basic_json& j)
+    const_reference at(const typename object_t::key_type& key) const
     {
-        std::vector<uint8_t> result;
-        to_msgpack_internal(j, result);
-        return result;
+        // at only works for objects
+        if (JSON_LIKELY(is_object()))
+        {
+            JSON_TRY
+            {
+                return m_value.object->at(key);
+            }
+            JSON_CATCH (std::out_of_range&)
+            {
+                // create better exception explanation
+                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
+            }
+        }
+        else
+        {
+            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
+        }
     }
 
     /*!
-    @brief create a JSON value from a byte vector in MessagePack format
-
-    Deserializes a given byte vector @a v to a JSON value using the MessagePack
-    serialization format.
-
-    The library maps MessagePack types to JSON value types as follows:
-
-    MessagePack type | JSON value type | first byte
-    ---------------- | --------------- | ----------
-    positive fixint  | number_unsigned | 0x00..0x7f
-    fixmap           | object          | 0x80..0x8f
-    fixarray         | array           | 0x90..0x9f
-    fixstr           | string          | 0xa0..0xbf
-    nil              | `null`          | 0xc0
-    false            | `false`         | 0xc2
-    true             | `true`          | 0xc3
-    float 32         | number_float    | 0xca
-    float 64         | number_float    | 0xcb
-    uint 8           | number_unsigned | 0xcc
-    uint 16          | number_unsigned | 0xcd
-    uint 32          | number_unsigned | 0xce
-    uint 64          | number_unsigned | 0xcf
-    int 8            | number_integer  | 0xd0
-    int 16           | number_integer  | 0xd1
-    int 32           | number_integer  | 0xd2
-    int 64           | number_integer  | 0xd3
-    str 8            | string          | 0xd9
-    str 16           | string          | 0xda
-    str 32           | string          | 0xdb
-    array 16         | array           | 0xdc
-    array 32         | array           | 0xdd
-    map 16           | object          | 0xde
-    map 32           | object          | 0xdf
-    negative fixint  | number_integer  | 0xe0-0xff
+    @brief access specified array element
 
-    @warning The mapping is **incomplete** in the sense that not all
-             MessagePack types can be converted to a JSON value. The following
-             MessagePack types are not supported and will yield parse errors:
-              - bin 8 - bin 32 (0xc4..0xc6)
-              - ext 8 - ext 32 (0xc7..0xc9)
-              - fixext 1 - fixext 16 (0xd4..0xd8)
+    Returns a reference to the element at specified location @a idx.
 
-    @note Any MessagePack output created @ref to_msgpack can be successfully
-          parsed by @ref from_msgpack.
+    @note If @a idx is beyond the range of the array (i.e., `idx >= size()`),
+    then the array is silently filled up with `null` values to make `idx` a
+    valid reference to the last stored element.
 
-    @param[in] v  a byte vector in MessagePack format
-    @param[in] start_index the index to start reading from @a v (0 by default)
-    @return deserialized JSON value
+    @param[in] idx  index of the element to access
 
-    @throw parse_error.110 if the given vector ends prematurely
-    @throw parse_error.112 if unsupported features from MessagePack were
-    used in the given vector @a v or if the input is not valid MessagePack
-    @throw parse_error.113 if a string was expected as map key, but not found
+    @return reference to the element at index @a idx
 
-    @complexity Linear in the size of the byte vector @a v.
+    @throw type_error.305 if the JSON value is not an array or null; in that
+    cases, using the [] operator with an index makes no sense.
 
-    @liveexample{The example shows the deserialization of a byte vector in
-    MessagePack format to a JSON value.,from_msgpack}
+    @complexity Constant if @a idx is in the range of the array. Otherwise
+    linear in `idx - size()`.
 
-    @sa http://msgpack.org
-    @sa @ref to_msgpack(const basic_json&) for the analogous serialization
-    @sa @ref from_cbor(const std::vector<uint8_t>&, const size_t) for the
-        related CBOR format
+    @liveexample{The example below shows how array elements can be read and
+    written using `[]` operator. Note the addition of `null`
+    values.,operatorarray__size_type}
 
-    @since version 2.0.9, parameter @a start_index since 2.1.1
+    @since version 1.0.0
     */
-    static basic_json from_msgpack(const std::vector<uint8_t>& v,
-                                   const size_t start_index = 0)
+    reference operator[](size_type idx)
     {
-        size_t i = start_index;
-        return from_msgpack_internal(v, i);
-    }
+        // implicitly convert null value to an empty array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value.array = create<array_t>();
+            assert_invariant();
+        }
 
-    /*!
-    @brief create a MessagePack serialization of a given JSON value
+        // operator[] only works for arrays
+        if (JSON_LIKELY(is_array()))
+        {
+            // fill up array with null values if given idx is outside range
+            if (idx >= m_value.array->size())
+            {
+                m_value.array->insert(m_value.array->end(),
+                                      idx - m_value.array->size() + 1,
+                                      basic_json());
+            }
 
-    Serializes a given JSON value @a j to a byte vector using the CBOR (Concise
-    Binary Object Representation) serialization format. CBOR is a binary
-    serialization format which aims to be more compact than JSON itself, yet
-    more efficient to parse.
+            return m_value.array->operator[](idx);
+        }
 
-    The library uses the following mapping from JSON values types to
-    CBOR types according to the CBOR specification (RFC 7049):
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
+    }
 
-    JSON value type | value/range                                | CBOR type                          | first byte
-    --------------- | ------------------------------------------ | ---------------------------------- | ---------------
-    null            | `null`                                     | Null                               | 0xf6
-    boolean         | `true`                                     | True                               | 0xf5
-    boolean         | `false`                                    | False                              | 0xf4
-    number_integer  | -9223372036854775808..-2147483649          | Negative integer (8 bytes follow)  | 0x3b
-    number_integer  | -2147483648..-32769                        | Negative integer (4 bytes follow)  | 0x3a
-    number_integer  | -32768..-129                               | Negative integer (2 bytes follow)  | 0x39
-    number_integer  | -128..-25                                  | Negative integer (1 byte follow)   | 0x38
-    number_integer  | -24..-1                                    | Negative integer                   | 0x20..0x37
-    number_integer  | 0..23                                      | Integer                            | 0x00..0x17
-    number_integer  | 24..255                                    | Unsigned integer (1 byte follow)   | 0x18
-    number_integer  | 256..65535                                 | Unsigned integer (2 bytes follow)  | 0x19
-    number_integer  | 65536..4294967295                          | Unsigned integer (4 bytes follow)  | 0x1a
-    number_integer  | 4294967296..18446744073709551615           | Unsigned integer (8 bytes follow)  | 0x1b
-    number_unsigned | 0..23                                      | Integer                            | 0x00..0x17
-    number_unsigned | 24..255                                    | Unsigned integer (1 byte follow)   | 0x18
-    number_unsigned | 256..65535                                 | Unsigned integer (2 bytes follow)  | 0x19
-    number_unsigned | 65536..4294967295                          | Unsigned integer (4 bytes follow)  | 0x1a
-    number_unsigned | 4294967296..18446744073709551615           | Unsigned integer (8 bytes follow)  | 0x1b
-    number_float    | *any value*                                | Double-Precision Float             | 0xfb
-    string          | *length*: 0..23                            | UTF-8 string                       | 0x60..0x77
-    string          | *length*: 23..255                          | UTF-8 string (1 byte follow)       | 0x78
-    string          | *length*: 256..65535                       | UTF-8 string (2 bytes follow)      | 0x79
-    string          | *length*: 65536..4294967295                | UTF-8 string (4 bytes follow)      | 0x7a
-    string          | *length*: 4294967296..18446744073709551615 | UTF-8 string (8 bytes follow)      | 0x7b
-    array           | *size*: 0..23                              | array                              | 0x80..0x97
-    array           | *size*: 23..255                            | array (1 byte follow)              | 0x98
-    array           | *size*: 256..65535                         | array (2 bytes follow)             | 0x99
-    array           | *size*: 65536..4294967295                  | array (4 bytes follow)             | 0x9a
-    array           | *size*: 4294967296..18446744073709551615   | array (8 bytes follow)             | 0x9b
-    object          | *size*: 0..23                              | map                                | 0xa0..0xb7
-    object          | *size*: 23..255                            | map (1 byte follow)                | 0xb8
-    object          | *size*: 256..65535                         | map (2 bytes follow)               | 0xb9
-    object          | *size*: 65536..4294967295                  | map (4 bytes follow)               | 0xba
-    object          | *size*: 4294967296..18446744073709551615   | map (8 bytes follow)               | 0xbb
+    /*!
+    @brief access specified array element
 
-    @note The mapping is **complete** in the sense that any JSON value type
-          can be converted to a CBOR value.
+    Returns a const reference to the element at specified location @a idx.
 
-    @note The following CBOR types are not used in the conversion:
-          - byte strings (0x40..0x5f)
-          - UTF-8 strings terminated by "break" (0x7f)
-          - arrays terminated by "break" (0x9f)
-          - maps terminated by "break" (0xbf)
-          - date/time (0xc0..0xc1)
-          - bignum (0xc2..0xc3)
-          - decimal fraction (0xc4)
-          - bigfloat (0xc5)
-          - tagged items (0xc6..0xd4, 0xd8..0xdb)
-          - expected conversions (0xd5..0xd7)
-          - simple values (0xe0..0xf3, 0xf8)
-          - undefined (0xf7)
-          - half and single-precision floats (0xf9-0xfa)
-          - break (0xff)
+    @param[in] idx  index of the element to access
 
-    @param[in] j  JSON value to serialize
-    @return MessagePack serialization as byte vector
+    @return const reference to the element at index @a idx
 
-    @complexity Linear in the size of the JSON value @a j.
+    @throw type_error.305 if the JSON value is not an array; in that case,
+    using the [] operator with an index makes no sense.
 
-    @liveexample{The example shows the serialization of a JSON value to a byte
-    vector in CBOR format.,to_cbor}
+    @complexity Constant.
 
-    @sa http://cbor.io
-    @sa @ref from_cbor(const std::vector<uint8_t>&, const size_t) for the
-        analogous deserialization
-    @sa @ref to_msgpack(const basic_json& for the related MessagePack format
+    @liveexample{The example below shows how array elements can be read using
+    the `[]` operator.,operatorarray__size_type_const}
 
-    @since version 2.0.9
+    @since version 1.0.0
     */
-    static std::vector<uint8_t> to_cbor(const basic_json& j)
+    const_reference operator[](size_type idx) const
     {
-        std::vector<uint8_t> result;
-        to_cbor_internal(j, result);
-        return result;
+        // const operator[] only works for arrays
+        if (JSON_LIKELY(is_array()))
+        {
+            return m_value.array->operator[](idx);
+        }
+
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
     }
 
     /*!
-    @brief create a JSON value from a byte vector in CBOR format
+    @brief access specified object element
 
-    Deserializes a given byte vector @a v to a JSON value using the CBOR
-    (Concise Binary Object Representation) serialization format.
+    Returns a reference to the element at with specified key @a key.
 
-    The library maps CBOR types to JSON value types as follows:
+    @note If @a key is not found in the object, then it is silently added to
+    the object and filled with a `null` value to make `key` a valid reference.
+    In case the value was `null` before, it is converted to an object.
 
-    CBOR type              | JSON value type | first byte
-    ---------------------- | --------------- | ----------
-    Integer                | number_unsigned | 0x00..0x17
-    Unsigned integer       | number_unsigned | 0x18
-    Unsigned integer       | number_unsigned | 0x19
-    Unsigned integer       | number_unsigned | 0x1a
-    Unsigned integer       | number_unsigned | 0x1b
-    Negative integer       | number_integer  | 0x20..0x37
-    Negative integer       | number_integer  | 0x38
-    Negative integer       | number_integer  | 0x39
-    Negative integer       | number_integer  | 0x3a
-    Negative integer       | number_integer  | 0x3b
-    Negative integer       | number_integer  | 0x40..0x57
-    UTF-8 string           | string          | 0x60..0x77
-    UTF-8 string           | string          | 0x78
-    UTF-8 string           | string          | 0x79
-    UTF-8 string           | string          | 0x7a
-    UTF-8 string           | string          | 0x7b
-    UTF-8 string           | string          | 0x7f
-    array                  | array           | 0x80..0x97
-    array                  | array           | 0x98
-    array                  | array           | 0x99
-    array                  | array           | 0x9a
-    array                  | array           | 0x9b
-    array                  | array           | 0x9f
-    map                    | object          | 0xa0..0xb7
-    map                    | object          | 0xb8
-    map                    | object          | 0xb9
-    map                    | object          | 0xba
-    map                    | object          | 0xbb
-    map                    | object          | 0xbf
-    False                  | `false`         | 0xf4
-    True                   | `true`          | 0xf5
-    Nill                   | `null`          | 0xf6
-    Half-Precision Float   | number_float    | 0xf9
-    Single-Precision Float | number_float    | 0xfa
-    Double-Precision Float | number_float    | 0xfb
+    @param[in] key  key of the element to access
 
-    @warning The mapping is **incomplete** in the sense that not all CBOR
-             types can be converted to a JSON value. The following CBOR types
-             are not supported and will yield parse errors (parse_error.112):
-             - byte strings (0x40..0x5f)
-             - date/time (0xc0..0xc1)
-             - bignum (0xc2..0xc3)
-             - decimal fraction (0xc4)
-             - bigfloat (0xc5)
-             - tagged items (0xc6..0xd4, 0xd8..0xdb)
-             - expected conversions (0xd5..0xd7)
-             - simple values (0xe0..0xf3, 0xf8)
-             - undefined (0xf7)
+    @return reference to the element at key @a key
 
-    @warning CBOR allows map keys of any type, whereas JSON only allows
-             strings as keys in object values. Therefore, CBOR maps with keys
-             other than UTF-8 strings are rejected (parse_error.113).
+    @throw type_error.305 if the JSON value is not an object or null; in that
+    cases, using the [] operator with a key makes no sense.
 
-    @note Any CBOR output created @ref to_cbor can be successfully parsed by
-          @ref from_cbor.
+    @complexity Logarithmic in the size of the container.
 
-    @param[in] v  a byte vector in CBOR format
-    @param[in] start_index the index to start reading from @a v (0 by default)
-    @return deserialized JSON value
+    @liveexample{The example below shows how object elements can be read and
+    written using the `[]` operator.,operatorarray__key_type}
 
-    @throw parse_error.110 if the given vector ends prematurely
-    @throw parse_error.112 if unsupported features from CBOR were
-    used in the given vector @a v or if the input is not valid CBOR
-    @throw parse_error.113 if a string was expected as map key, but not found
-
-    @complexity Linear in the size of the byte vector @a v.
-
-    @liveexample{The example shows the deserialization of a byte vector in CBOR
-    format to a JSON value.,from_cbor}
-
-    @sa http://cbor.io
-    @sa @ref to_cbor(const basic_json&) for the analogous serialization
-    @sa @ref from_msgpack(const std::vector<uint8_t>&, const size_t) for the
-        related MessagePack format
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
 
-    @since version 2.0.9, parameter @a start_index since 2.1.1
+    @since version 1.0.0
     */
-    static basic_json from_cbor(const std::vector<uint8_t>& v,
-                                const size_t start_index = 0)
+    reference operator[](const typename object_t::key_type& key)
     {
-        size_t i = start_index;
-        return from_cbor_internal(v, i);
-    }
+        // implicitly convert null value to an empty object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value.object = create<object_t>();
+            assert_invariant();
+        }
 
-    /// @}
+        // operator[] only works for objects
+        if (JSON_LIKELY(is_object()))
+        {
+            return m_value.object->operator[](key);
+        }
 
-    ///////////////////////////
-    // convenience functions //
-    ///////////////////////////
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
+    }
 
     /*!
-    @brief return the type as string
+    @brief read-only access specified object element
 
-    Returns the type name as string to be used in error messages - usually to
-    indicate that a function was called on a wrong JSON type.
+    Returns a const reference to the element at with specified key @a key. No
+    bounds checking is performed.
+
+    @warning If the element with key @a key does not exist, the behavior is
+    undefined.
 
-    @return basically a string representation of a the @a m_type member
+    @param[in] key  key of the element to access
 
-    @complexity Constant.
+    @return const reference to the element at key @a key
 
-    @liveexample{The following code exemplifies `type_name()` for all JSON
-    types.,type_name}
+    @pre The element with key @a key must exist. **This precondition is
+         enforced with an assertion.**
 
-    @since version 1.0.0, public since 2.1.0
+    @throw type_error.305 if the JSON value is not an object; in that case,
+    using the [] operator with a key makes no sense.
+
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read using
+    the `[]` operator.,operatorarray__key_type_const}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
+
+    @since version 1.0.0
     */
-    std::string type_name() const
+    const_reference operator[](const typename object_t::key_type& key) const
     {
+        // const operator[] only works for objects
+        if (JSON_LIKELY(is_object()))
         {
-            switch (m_type)
-            {
-                case value_t::null:
-                    return "null";
-                case value_t::object:
-                    return "object";
-                case value_t::array:
-                    return "array";
-                case value_t::string:
-                    return "string";
-                case value_t::boolean:
-                    return "boolean";
-                case value_t::discarded:
-                    return "discarded";
-                default:
-                    return "number";
-            }
+            assert(m_value.object->find(key) != m_value.object->end());
+            return m_value.object->find(key)->second;
         }
+
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
     }
 
+    /*!
+    @brief access specified object element
 
-  private:
-    //////////////////////
-    // member variables //
-    //////////////////////
+    Returns a reference to the element at with specified key @a key.
 
-    /// the type of the current element
-    value_t m_type = value_t::null;
+    @note If @a key is not found in the object, then it is silently added to
+    the object and filled with a `null` value to make `key` a valid reference.
+    In case the value was `null` before, it is converted to an object.
 
-    /// the value of the current element
-    json_value m_value = {};
+    @param[in] key  key of the element to access
 
+    @return reference to the element at key @a key
 
-  private:
-    ///////////////
-    // iterators //
-    ///////////////
+    @throw type_error.305 if the JSON value is not an object or null; in that
+    cases, using the [] operator with a key makes no sense.
 
-    /*!
-    @brief an iterator for primitive JSON types
+    @complexity Logarithmic in the size of the container.
+
+    @liveexample{The example below shows how object elements can be read and
+    written using the `[]` operator.,operatorarray__key_type}
+
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
 
-    This class models an iterator for primitive JSON types (boolean, number,
-    string). It's only purpose is to allow the iterator/const_iterator classes
-    to "iterate" over primitive values. Internally, the iterator is modeled by
-    a `difference_type` variable. Value begin_value (`0`) models the begin,
-    end_value (`1`) models past the end.
+    @since version 1.1.0
     */
-    class primitive_iterator_t
+    template<typename T>
+    reference operator[](T* key)
     {
-      public:
-
-        difference_type get_value() const noexcept
-        {
-            return m_it;
-        }
-        /// set iterator to a defined beginning
-        void set_begin() noexcept
+        // implicitly convert null to object
+        if (is_null())
         {
-            m_it = begin_value;
+            m_type = value_t::object;
+            m_value = value_t::object;
+            assert_invariant();
         }
 
-        /// set iterator to a defined past the end
-        void set_end() noexcept
+        // at only works for objects
+        if (JSON_LIKELY(is_object()))
         {
-            m_it = end_value;
+            return m_value.object->operator[](key);
         }
 
-        /// return whether the iterator can be dereferenced
-        constexpr bool is_begin() const noexcept
-        {
-            return (m_it == begin_value);
-        }
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
+    }
 
-        /// return whether the iterator is at end
-        constexpr bool is_end() const noexcept
-        {
-            return (m_it == end_value);
-        }
+    /*!
+    @brief read-only access specified object element
 
-        friend constexpr bool operator==(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it == rhs.m_it;
-        }
+    Returns a const reference to the element at with specified key @a key. No
+    bounds checking is performed.
 
-        friend constexpr bool operator!=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return !(lhs == rhs);
-        }
+    @warning If the element with key @a key does not exist, the behavior is
+    undefined.
 
-        friend constexpr bool operator<(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it < rhs.m_it;
-        }
+    @param[in] key  key of the element to access
 
-        friend constexpr bool operator<=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it <= rhs.m_it;
-        }
+    @return const reference to the element at key @a key
 
-        friend constexpr bool operator>(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it > rhs.m_it;
-        }
+    @pre The element with key @a key must exist. **This precondition is
+         enforced with an assertion.**
 
-        friend constexpr bool operator>=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it >= rhs.m_it;
-        }
+    @throw type_error.305 if the JSON value is not an object; in that case,
+    using the [] operator with a key makes no sense.
 
-        primitive_iterator_t operator+(difference_type i)
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
+    @complexity Logarithmic in the size of the container.
 
-        friend constexpr difference_type operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
-        {
-            return lhs.m_it - rhs.m_it;
-        }
+    @liveexample{The example below shows how object elements can be read using
+    the `[]` operator.,operatorarray__key_type_const}
 
-        friend std::ostream& operator<<(std::ostream& os, primitive_iterator_t it)
-        {
-            return os << it.m_it;
-        }
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref value() for access by value with a default value
 
-        primitive_iterator_t& operator++()
+    @since version 1.1.0
+    */
+    template<typename T>
+    const_reference operator[](T* key) const
+    {
+        // at only works for objects
+        if (JSON_LIKELY(is_object()))
         {
-            ++m_it;
-            return *this;
+            assert(m_value.object->find(key) != m_value.object->end());
+            return m_value.object->find(key)->second;
         }
 
-        primitive_iterator_t operator++(int)
-        {
-            auto result = *this;
-            m_it++;
-            return result;
-        }
+        JSON_THROW(type_error::create(305, "cannot use operator[] with " + std::string(type_name())));
+    }
 
-        primitive_iterator_t& operator--()
-        {
-            --m_it;
-            return *this;
-        }
+    /*!
+    @brief access specified object element with default value
 
-        primitive_iterator_t operator--(int)
-        {
-            auto result = *this;
-            m_it--;
-            return result;
-        }
+    Returns either a copy of an object's element at the specified key @a key
+    or a given default value if no element with key @a key exists.
 
-        primitive_iterator_t& operator+=(difference_type n)
-        {
-            m_it += n;
-            return *this;
-        }
+    The function is basically equivalent to executing
+    @code {.cpp}
+    try {
+        return at(key);
+    } catch(out_of_range) {
+        return default_value;
+    }
+    @endcode
 
-        primitive_iterator_t& operator-=(difference_type n)
-        {
-            m_it -= n;
-            return *this;
-        }
+    @note Unlike @ref at(const typename object_t::key_type&), this function
+    does not throw if the given key @a key was not found.
 
-      private:
-        static constexpr difference_type begin_value = 0;
-        static constexpr difference_type end_value = begin_value + 1;
+    @note Unlike @ref operator[](const typename object_t::key_type& key), this
+    function does not implicitly add an element to the position defined by @a
+    key. This function is furthermore also applicable to const objects.
 
-        /// iterator as signed integer type
-        difference_type m_it = std::numeric_limits<std::ptrdiff_t>::denorm_min();
-    };
+    @param[in] key  key of the element to access
+    @param[in] default_value  the value to return if @a key is not found
 
-    /*!
-    @brief an iterator value
+    @tparam ValueType type compatible to JSON values, for instance `int` for
+    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
+    JSON arrays. Note the type of the expected value at @a key and the default
+    value @a default_value must be compatible.
 
-    @note This structure could easily be a union, but MSVC currently does not
-    allow unions members with complex constructors, see
-    https://github.com/nlohmann/json/pull/105.
-    */
-    struct internal_iterator
-    {
-        /// iterator for JSON objects
-        typename object_t::iterator object_iterator;
-        /// iterator for JSON arrays
-        typename array_t::iterator array_iterator;
-        /// generic iterator for all other types
-        primitive_iterator_t primitive_iterator;
+    @return copy of the element at key @a key or @a default_value if @a key
+    is not found
 
-        /// create an uninitialized internal_iterator
-        internal_iterator() noexcept
-            : object_iterator(), array_iterator(), primitive_iterator()
-        {}
-    };
+    @throw type_error.306 if the JSON value is not an object; in that case,
+    using `value()` with a key makes no sense.
 
-    /// proxy class for the iterator_wrapper functions
-    template<typename IteratorType>
-    class iteration_proxy
-    {
-      private:
-        /// helper class for iteration
-        class iteration_proxy_internal
-        {
-          private:
-            /// the iterator
-            IteratorType anchor;
-            /// an index for arrays (used to create key names)
-            size_t array_index = 0;
+    @complexity Logarithmic in the size of the container.
 
-          public:
-            explicit iteration_proxy_internal(IteratorType it) noexcept
-                : anchor(it)
-            {}
+    @liveexample{The example below shows how object elements can be queried
+    with a default value.,basic_json__value}
 
-            /// dereference operator (needed for range-based for)
-            iteration_proxy_internal& operator*()
-            {
-                return *this;
-            }
+    @sa @ref at(const typename object_t::key_type&) for access by reference
+    with range checking
+    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    access by reference
 
-            /// increment operator (needed for range-based for)
-            iteration_proxy_internal& operator++()
+    @since version 1.0.0
+    */
+    template<class ValueType, typename std::enable_if<
+                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
+    ValueType value(const typename object_t::key_type& key, const ValueType& default_value) const
+    {
+        // at only works for objects
+        if (JSON_LIKELY(is_object()))
+        {
+            // if key is found, return value and given default value otherwise
+            const auto it = find(key);
+            if (it != end())
             {
-                ++anchor;
-                ++array_index;
-
-                return *this;
+                return *it;
             }
 
-            /// inequality operator (needed for range-based for)
-            bool operator!= (const iteration_proxy_internal& o) const
-            {
-                return anchor != o.anchor;
-            }
+            return default_value;
+        }
 
-            /// return key of the iterator
-            typename basic_json::string_t key() const
-            {
-                assert(anchor.m_object != nullptr);
+        JSON_THROW(type_error::create(306, "cannot use value() with " + std::string(type_name())));
+    }
 
-                switch (anchor.m_object->type())
-                {
-                    // use integer array index as key
-                    case value_t::array:
-                    {
-                        return std::to_string(array_index);
-                    }
+    /*!
+    @brief overload for a default value of type const char*
+    @copydoc basic_json::value(const typename object_t::key_type&, ValueType) const
+    */
+    string_t value(const typename object_t::key_type& key, const char* default_value) const
+    {
+        return value(key, string_t(default_value));
+    }
 
-                    // use key from the object
-                    case value_t::object:
-                    {
-                        return anchor.key();
-                    }
+    /*!
+    @brief access specified object element via JSON Pointer with default value
 
-                    // use an empty key for all primitive types
-                    default:
-                    {
-                        return "";
-                    }
-                }
-            }
+    Returns either a copy of an object's element at the specified key @a key
+    or a given default value if no element with key @a key exists.
 
-            /// return value of the iterator
-            typename IteratorType::reference value() const
-            {
-                return anchor.value();
-            }
-        };
+    The function is basically equivalent to executing
+    @code {.cpp}
+    try {
+        return at(ptr);
+    } catch(out_of_range) {
+        return default_value;
+    }
+    @endcode
 
-        /// the container to iterate
-        typename IteratorType::reference container;
+    @note Unlike @ref at(const json_pointer&), this function does not throw
+    if the given key @a key was not found.
 
-      public:
-        /// construct iteration proxy from a container
-        explicit iteration_proxy(typename IteratorType::reference cont)
-            : container(cont)
-        {}
+    @param[in] ptr  a JSON pointer to the element to access
+    @param[in] default_value  the value to return if @a ptr found no value
 
-        /// return iterator begin (needed for range-based for)
-        iteration_proxy_internal begin() noexcept
-        {
-            return iteration_proxy_internal(container.begin());
-        }
+    @tparam ValueType type compatible to JSON values, for instance `int` for
+    JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for
+    JSON arrays. Note the type of the expected value at @a key and the default
+    value @a default_value must be compatible.
 
-        /// return iterator end (needed for range-based for)
-        iteration_proxy_internal end() noexcept
-        {
-            return iteration_proxy_internal(container.end());
-        }
-    };
+    @return copy of the element at key @a key or @a default_value if @a key
+    is not found
 
-  public:
-    /*!
-    @brief a template for a random access iterator for the @ref basic_json class
+    @throw type_error.306 if the JSON value is not an objec; in that case,
+    using `value()` with a key makes no sense.
 
-    This class implements a both iterators (iterator and const_iterator) for the
-    @ref basic_json class.
+    @complexity Logarithmic in the size of the container.
 
-    @note An iterator is called *initialized* when a pointer to a JSON value
-          has been set (e.g., by a constructor or a copy assignment). If the
-          iterator is default-constructed, it is *uninitialized* and most
-          methods are undefined. **The library uses assertions to detect calls
-          on uninitialized iterators.**
+    @liveexample{The example below shows how object elements can be queried
+    with a default value.,basic_json__value_ptr}
 
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
+    @sa @ref operator[](const json_pointer&) for unchecked access by reference
 
-    @since version 1.0.0, simplified in version 2.0.9
+    @since version 2.0.2
     */
-    template<typename U>
-    class iter_impl : public std::iterator<std::random_access_iterator_tag, U>
+    template<class ValueType, typename std::enable_if<
+                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
+    ValueType value(const json_pointer& ptr, const ValueType& default_value) const
     {
-        /// allow basic_json to access private members
-        friend class basic_json;
-
-        // make sure U is basic_json or const basic_json
-        static_assert(std::is_same<U, basic_json>::value
-                      or std::is_same<U, const basic_json>::value,
-                      "iter_impl only accepts (const) basic_json");
-
-      public:
-        /// the type of the values when the iterator is dereferenced
-        using value_type = typename basic_json::value_type;
-        /// a type to represent differences between iterators
-        using difference_type = typename basic_json::difference_type;
-        /// defines a pointer to the type iterated over (value_type)
-        using pointer = typename std::conditional<std::is_const<U>::value,
-              typename basic_json::const_pointer,
-              typename basic_json::pointer>::type;
-        /// defines a reference to the type iterated over (value_type)
-        using reference = typename std::conditional<std::is_const<U>::value,
-              typename basic_json::const_reference,
-              typename basic_json::reference>::type;
-        /// the category of the iterator
-        using iterator_category = std::bidirectional_iterator_tag;
-
-        /// default constructor
-        iter_impl() = default;
-
-        /*!
-        @brief constructor for a given JSON instance
-        @param[in] object  pointer to a JSON object for this iterator
-        @pre object != nullptr
-        @post The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        explicit iter_impl(pointer object) noexcept
-            : m_object(object)
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = typename object_t::iterator();
-                    break;
-                }
-
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = typename array_t::iterator();
-                    break;
-                }
-
-                default:
-                {
-                    m_it.primitive_iterator = primitive_iterator_t();
-                    break;
-                }
-            }
-        }
-
-        /*
-        Use operator `const_iterator` instead of `const_iterator(const iterator&
-        other) noexcept` to avoid two class definitions for @ref iterator and
-        @ref const_iterator.
-
-        This function is only called if this class is an @ref iterator. If this
-        class is a @ref const_iterator this function is not called.
-        */
-        operator const_iterator() const
+        // at only works for objects
+        if (JSON_LIKELY(is_object()))
         {
-            const_iterator ret;
-
-            if (m_object)
+            // if pointer resolves a value, return it or use default value
+            JSON_TRY
             {
-                ret.m_object = m_object;
-                ret.m_it = m_it;
+                return ptr.get_checked(this);
+            }
+            JSON_CATCH (out_of_range&)
+            {
+                return default_value;
             }
-
-            return ret;
         }
 
-        /*!
-        @brief copy constructor
-        @param[in] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
-        */
-        iter_impl(const iter_impl& other) noexcept
-            : m_object(other.m_object), m_it(other.m_it)
-        {}
+        JSON_THROW(type_error::create(306, "cannot use value() with " + std::string(type_name())));
+    }
 
-        /*!
-        @brief copy assignment
-        @param[in,out] other  iterator to copy from
-        @note It is not checked whether @a other is initialized.
-        */
-        iter_impl& operator=(iter_impl other) noexcept(
-            std::is_nothrow_move_constructible<pointer>::value and
-            std::is_nothrow_move_assignable<pointer>::value and
-            std::is_nothrow_move_constructible<internal_iterator>::value and
-            std::is_nothrow_move_assignable<internal_iterator>::value
-        )
-        {
-            std::swap(m_object, other.m_object);
-            std::swap(m_it, other.m_it);
-            return *this;
-        }
+    /*!
+    @brief overload for a default value of type const char*
+    @copydoc basic_json::value(const json_pointer&, ValueType) const
+    */
+    string_t value(const json_pointer& ptr, const char* default_value) const
+    {
+        return value(ptr, string_t(default_value));
+    }
 
-      private:
-        /*!
-        @brief set the iterator to the first value
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        void set_begin() noexcept
-        {
-            assert(m_object != nullptr);
+    /*!
+    @brief access the first element
 
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = m_object->m_value.object->begin();
-                    break;
-                }
+    Returns a reference to the first element in the container. For a JSON
+    container `c`, the expression `c.front()` is equivalent to `*c.begin()`.
 
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = m_object->m_value.array->begin();
-                    break;
-                }
+    @return In case of a structured type (array or object), a reference to the
+    first element is returned. In case of number, string, or boolean values, a
+    reference to the value is returned.
 
-                case basic_json::value_t::null:
-                {
-                    // set to end so begin()==end() is true: null is empty
-                    m_it.primitive_iterator.set_end();
-                    break;
-                }
+    @complexity Constant.
 
-                default:
-                {
-                    m_it.primitive_iterator.set_begin();
-                    break;
-                }
-            }
-        }
+    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
+    or an empty array or object (undefined behavior, **guarded by
+    assertions**).
+    @post The JSON value remains unchanged.
 
-        /*!
-        @brief set the iterator past the last value
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        void set_end() noexcept
-        {
-            assert(m_object != nullptr);
+    @throw invalid_iterator.214 when called on `null` value
 
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    m_it.object_iterator = m_object->m_value.object->end();
-                    break;
-                }
+    @liveexample{The following code shows an example for `front()`.,front}
 
-                case basic_json::value_t::array:
-                {
-                    m_it.array_iterator = m_object->m_value.array->end();
-                    break;
-                }
+    @sa @ref back() -- access the last element
 
-                default:
-                {
-                    m_it.primitive_iterator.set_end();
-                    break;
-                }
-            }
-        }
+    @since version 1.0.0
+    */
+    reference front()
+    {
+        return *begin();
+    }
 
-      public:
-        /*!
-        @brief return a reference to the value pointed to by the iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference operator*() const
-        {
-            assert(m_object != nullptr);
+    /*!
+    @copydoc basic_json::front()
+    */
+    const_reference front() const
+    {
+        return *cbegin();
+    }
 
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    assert(m_it.object_iterator != m_object->m_value.object->end());
-                    return m_it.object_iterator->second;
-                }
+    /*!
+    @brief access the last element
 
-                case basic_json::value_t::array:
-                {
-                    assert(m_it.array_iterator != m_object->m_value.array->end());
-                    return *m_it.array_iterator;
-                }
+    Returns a reference to the last element in the container. For a JSON
+    container `c`, the expression `c.back()` is equivalent to
+    @code {.cpp}
+    auto tmp = c.end();
+    --tmp;
+    return *tmp;
+    @endcode
 
-                case basic_json::value_t::null:
-                {
-                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
-                }
+    @return In case of a structured type (array or object), a reference to the
+    last element is returned. In case of number, string, or boolean values, a
+    reference to the value is returned.
 
-                default:
-                {
-                    if (m_it.primitive_iterator.is_begin())
-                    {
-                        return *m_object;
-                    }
+    @complexity Constant.
 
-                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
-                }
-            }
-        }
+    @pre The JSON value must not be `null` (would throw `std::out_of_range`)
+    or an empty array or object (undefined behavior, **guarded by
+    assertions**).
+    @post The JSON value remains unchanged.
 
-        /*!
-        @brief dereference the iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        pointer operator->() const
-        {
-            assert(m_object != nullptr);
+    @throw invalid_iterator.214 when called on a `null` value. See example
+    below.
 
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    assert(m_it.object_iterator != m_object->m_value.object->end());
-                    return &(m_it.object_iterator->second);
-                }
+    @liveexample{The following code shows an example for `back()`.,back}
 
-                case basic_json::value_t::array:
-                {
-                    assert(m_it.array_iterator != m_object->m_value.array->end());
-                    return &*m_it.array_iterator;
-                }
+    @sa @ref front() -- access the first element
 
-                default:
-                {
-                    if (m_it.primitive_iterator.is_begin())
-                    {
-                        return m_object;
-                    }
+    @since version 1.0.0
+    */
+    reference back()
+    {
+        auto tmp = end();
+        --tmp;
+        return *tmp;
+    }
 
-                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
-                }
-            }
-        }
+    /*!
+    @copydoc basic_json::back()
+    */
+    const_reference back() const
+    {
+        auto tmp = cend();
+        --tmp;
+        return *tmp;
+    }
 
-        /*!
-        @brief post-increment (it++)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        iter_impl operator++(int)
-        {
-            auto result = *this;
-            ++(*this);
-            return result;
-        }
+    /*!
+    @brief remove element given an iterator
 
-        /*!
-        @brief pre-increment (++it)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        iter_impl& operator++()
-        {
-            assert(m_object != nullptr);
+    Removes the element specified by iterator @a pos. The iterator @a pos must
+    be valid and dereferenceable. Thus the `end()` iterator (which is valid,
+    but is not dereferenceable) cannot be used as a value for @a pos.
 
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    std::advance(m_it.object_iterator, 1);
-                    break;
-                }
+    If called on a primitive type other than `null`, the resulting JSON value
+    will be `null`.
 
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, 1);
-                    break;
-                }
+    @param[in] pos iterator to the element to remove
+    @return Iterator following the last removed element. If the iterator @a
+    pos refers to the last element, the `end()` iterator is returned.
 
-                default:
-                {
-                    ++m_it.primitive_iterator;
-                    break;
-                }
-            }
+    @tparam IteratorType an @ref iterator or @ref const_iterator
 
-            return *this;
-        }
-
-        /*!
-        @brief post-decrement (it--)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        iter_impl operator--(int)
-        {
-            auto result = *this;
-            --(*this);
-            return result;
-        }
-
-        /*!
-        @brief pre-decrement (--it)
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        iter_impl& operator--()
-        {
-            assert(m_object != nullptr);
+    @post Invalidates iterators and references at or after the point of the
+    erase, including the `end()` iterator.
 
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    std::advance(m_it.object_iterator, -1);
-                    break;
-                }
+    @throw type_error.307 if called on a `null` value; example: `"cannot use
+    erase() with null"`
+    @throw invalid_iterator.202 if called on an iterator which does not belong
+    to the current JSON value; example: `"iterator does not fit current
+    value"`
+    @throw invalid_iterator.205 if called on a primitive type with invalid
+    iterator (i.e., any iterator which is not `begin()`); example: `"iterator
+    out of range"`
 
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, -1);
-                    break;
-                }
+    @complexity The complexity depends on the type:
+    - objects: amortized constant
+    - arrays: linear in distance between @a pos and the end of the container
+    - strings: linear in the length of the string
+    - other types: constant
 
-                default:
-                {
-                    --m_it.primitive_iterator;
-                    break;
-                }
-            }
+    @liveexample{The example shows the result of `erase()` for different JSON
+    types.,erase__IteratorType}
 
-            return *this;
-        }
+    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
 
-        /*!
-        @brief  comparison: equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator==(const iter_impl& other) const
+    @since version 1.0.0
+    */
+    template<class IteratorType, typename std::enable_if<
+                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
+                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
+             = 0>
+    IteratorType erase(IteratorType pos)
+    {
+        // make sure iterator fits the current value
+        if (JSON_UNLIKELY(this != pos.m_object))
         {
-            // if objects are not the same, the comparison is undefined
-            if (m_object != other.m_object)
-            {
-                JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
-            }
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+        }
 
-            assert(m_object != nullptr);
+        IteratorType result = end();
 
-            switch (m_object->m_type)
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
             {
-                case basic_json::value_t::object:
+                if (JSON_UNLIKELY(not pos.m_it.primitive_iterator.is_begin()))
                 {
-                    return (m_it.object_iterator == other.m_it.object_iterator);
+                    JSON_THROW(invalid_iterator::create(205, "iterator out of range"));
                 }
 
-                case basic_json::value_t::array:
+                if (is_string())
                 {
-                    return (m_it.array_iterator == other.m_it.array_iterator);
+                    AllocatorType<string_t> alloc;
+                    std::allocator_traits<decltype(alloc)>::destroy(alloc, m_value.string);
+                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, m_value.string, 1);
+                    m_value.string = nullptr;
                 }
 
-                default:
-                {
-                    return (m_it.primitive_iterator == other.m_it.primitive_iterator);
-                }
+                m_type = value_t::null;
+                assert_invariant();
+                break;
             }
-        }
-
-        /*!
-        @brief  comparison: not equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator!=(const iter_impl& other) const
-        {
-            return not operator==(other);
-        }
 
-        /*!
-        @brief  comparison: smaller
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator<(const iter_impl& other) const
-        {
-            // if objects are not the same, the comparison is undefined
-            if (m_object != other.m_object)
+            case value_t::object:
             {
-                JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
+                result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator);
+                break;
             }
 
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
+            case value_t::array:
             {
-                case basic_json::value_t::object:
-                {
-                    JSON_THROW(invalid_iterator::create(213, "cannot compare order of object iterators"));
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return (m_it.array_iterator < other.m_it.array_iterator);
-                }
-
-                default:
-                {
-                    return (m_it.primitive_iterator < other.m_it.primitive_iterator);
-                }
+                result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator);
+                break;
             }
-        }
 
-        /*!
-        @brief  comparison: less than or equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator<=(const iter_impl& other) const
-        {
-            return not other.operator < (*this);
+            default:
+                JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
         }
 
-        /*!
-        @brief  comparison: greater than
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator>(const iter_impl& other) const
-        {
-            return not operator<=(other);
-        }
+        return result;
+    }
 
-        /*!
-        @brief  comparison: greater than or equal
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        bool operator>=(const iter_impl& other) const
-        {
-            return not operator<(other);
-        }
+    /*!
+    @brief remove elements given an iterator range
 
-        /*!
-        @brief  add to iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        iter_impl& operator+=(difference_type i)
-        {
-            assert(m_object != nullptr);
+    Removes the element specified by the range `[first; last)`. The iterator
+    @a first does not need to be dereferenceable if `first == last`: erasing
+    an empty range is a no-op.
 
-            switch (m_object->m_type)
-            {
-                case basic_json::value_t::object:
-                {
-                    JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));
-                }
+    If called on a primitive type other than `null`, the resulting JSON value
+    will be `null`.
 
-                case basic_json::value_t::array:
-                {
-                    std::advance(m_it.array_iterator, i);
-                    break;
-                }
+    @param[in] first iterator to the beginning of the range to remove
+    @param[in] last iterator past the end of the range to remove
+    @return Iterator following the last removed element. If the iterator @a
+    second refers to the last element, the `end()` iterator is returned.
 
-                default:
-                {
-                    m_it.primitive_iterator += i;
-                    break;
-                }
-            }
+    @tparam IteratorType an @ref iterator or @ref const_iterator
 
-            return *this;
-        }
+    @post Invalidates iterators and references at or after the point of the
+    erase, including the `end()` iterator.
 
-        /*!
-        @brief  subtract from iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        iter_impl& operator-=(difference_type i)
-        {
-            return operator+=(-i);
-        }
+    @throw type_error.307 if called on a `null` value; example: `"cannot use
+    erase() with null"`
+    @throw invalid_iterator.203 if called on iterators which does not belong
+    to the current JSON value; example: `"iterators do not fit current value"`
+    @throw invalid_iterator.204 if called on a primitive type with invalid
+    iterators (i.e., if `first != begin()` and `last != end()`); example:
+    `"iterators out of range"`
 
-        /*!
-        @brief  add to iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        iter_impl operator+(difference_type i)
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
+    @complexity The complexity depends on the type:
+    - objects: `log(size()) + std::distance(first, last)`
+    - arrays: linear in the distance between @a first and @a last, plus linear
+      in the distance between @a last and end of the container
+    - strings: linear in the length of the string
+    - other types: constant
+
+    @liveexample{The example shows the result of `erase()` for different JSON
+    types.,erase__IteratorType_IteratorType}
+
+    @sa @ref erase(IteratorType) -- removes the element at a given position
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
 
-        /*!
-        @brief  subtract from iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        iter_impl operator-(difference_type i)
+    @since version 1.0.0
+    */
+    template<class IteratorType, typename std::enable_if<
+                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
+                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
+             = 0>
+    IteratorType erase(IteratorType first, IteratorType last)
+    {
+        // make sure iterator fits the current value
+        if (JSON_UNLIKELY(this != first.m_object or this != last.m_object))
         {
-            auto result = *this;
-            result -= i;
-            return result;
+            JSON_THROW(invalid_iterator::create(203, "iterators do not fit current value"));
         }
 
-        /*!
-        @brief  return difference
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        difference_type operator-(const iter_impl& other) const
-        {
-            assert(m_object != nullptr);
+        IteratorType result = end();
 
-            switch (m_object->m_type)
+        switch (m_type)
+        {
+            case value_t::boolean:
+            case value_t::number_float:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::string:
             {
-                case basic_json::value_t::object:
+                if (JSON_LIKELY(not first.m_it.primitive_iterator.is_begin()
+                                or not last.m_it.primitive_iterator.is_end()))
                 {
-                    JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));
+                    JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
                 }
 
-                case basic_json::value_t::array:
+                if (is_string())
                 {
-                    return m_it.array_iterator - other.m_it.array_iterator;
+                    AllocatorType<string_t> alloc;
+                    std::allocator_traits<decltype(alloc)>::destroy(alloc, m_value.string);
+                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, m_value.string, 1);
+                    m_value.string = nullptr;
                 }
 
-                default:
-                {
-                    return m_it.primitive_iterator - other.m_it.primitive_iterator;
-                }
+                m_type = value_t::null;
+                assert_invariant();
+                break;
             }
-        }
 
-        /*!
-        @brief  access to successor
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference operator[](difference_type n) const
-        {
-            assert(m_object != nullptr);
-
-            switch (m_object->m_type)
+            case value_t::object:
             {
-                case basic_json::value_t::object:
-                {
-                    JSON_THROW(invalid_iterator::create(208, "cannot use operator[] for object iterators"));
-                }
-
-                case basic_json::value_t::array:
-                {
-                    return *std::next(m_it.array_iterator, n);
-                }
-
-                case basic_json::value_t::null:
-                {
-                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
-                }
-
-                default:
-                {
-                    if (m_it.primitive_iterator.get_value() == -n)
-                    {
-                        return *m_object;
-                    }
-
-                    JSON_THROW(invalid_iterator::create(214, "cannot get value"));
-                }
+                result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator,
+                                              last.m_it.object_iterator);
+                break;
             }
-        }
-
-        /*!
-        @brief  return the key of an object iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        typename object_t::key_type key() const
-        {
-            assert(m_object != nullptr);
 
-            if (m_object->is_object())
+            case value_t::array:
             {
-                return m_it.object_iterator->first;
+                result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator,
+                                             last.m_it.array_iterator);
+                break;
             }
 
-            JSON_THROW(invalid_iterator::create(207, "cannot use key() for non-object iterators"));
-        }
-
-        /*!
-        @brief  return the value of an iterator
-        @pre The iterator is initialized; i.e. `m_object != nullptr`.
-        */
-        reference value() const
-        {
-            return operator*();
+            default:
+                JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
         }
 
-      private:
-        /// associated JSON instance
-        pointer m_object = nullptr;
-        /// the actual iterator of the associated instance
-        internal_iterator m_it = internal_iterator();
-    };
+        return result;
+    }
 
     /*!
-    @brief a template for a reverse iterator class
+    @brief remove element from a JSON object given a key
 
-    @tparam Base the base iterator type to reverse. Valid types are @ref
-    iterator (to create @ref reverse_iterator) and @ref const_iterator (to
-    create @ref const_reverse_iterator).
+    Removes elements from a JSON object with the key value @a key.
 
-    @requirement The class satisfies the following concept requirements:
-    - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator):
-      The iterator that can be moved to point (forward and backward) to any
-      element in constant time.
-    - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator):
-      It is possible to write to the pointed-to element (only if @a Base is
-      @ref iterator).
+    @param[in] key value of the elements to remove
 
-    @since version 1.0.0
-    */
-    template<typename Base>
-    class json_reverse_iterator : public std::reverse_iterator<Base>
-    {
-      public:
-        /// shortcut to the reverse iterator adaptor
-        using base_iterator = std::reverse_iterator<Base>;
-        /// the reference type for the pointed-to element
-        using reference = typename Base::reference;
-
-        /// create reverse iterator from iterator
-        json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept
-            : base_iterator(it)
-        {}
+    @return Number of elements removed. If @a ObjectType is the default
+    `std::map` type, the return value will always be `0` (@a key was not
+    found) or `1` (@a key was found).
 
-        /// create reverse iterator from base class
-        json_reverse_iterator(const base_iterator& it) noexcept
-            : base_iterator(it)
-        {}
+    @post References and iterators to the erased elements are invalidated.
+    Other references and iterators are not affected.
 
-        /// post-increment (it++)
-        json_reverse_iterator operator++(int)
-        {
-            return base_iterator::operator++(1);
-        }
+    @throw type_error.307 when called on a type other than JSON object;
+    example: `"cannot use erase() with null"`
 
-        /// pre-increment (++it)
-        json_reverse_iterator& operator++()
-        {
-            base_iterator::operator++();
-            return *this;
-        }
+    @complexity `log(size()) + count(key)`
 
-        /// post-decrement (it--)
-        json_reverse_iterator operator--(int)
-        {
-            return base_iterator::operator--(1);
-        }
+    @liveexample{The example shows the effect of `erase()`.,erase__key_type}
 
-        /// pre-decrement (--it)
-        json_reverse_iterator& operator--()
-        {
-            base_iterator::operator--();
-            return *this;
-        }
+    @sa @ref erase(IteratorType) -- removes the element at a given position
+    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const size_type) -- removes the element from an array at
+    the given index
 
-        /// add to iterator
-        json_reverse_iterator& operator+=(difference_type i)
+    @since version 1.0.0
+    */
+    size_type erase(const typename object_t::key_type& key)
+    {
+        // this erase only works for objects
+        if (JSON_LIKELY(is_object()))
         {
-            base_iterator::operator+=(i);
-            return *this;
+            return m_value.object->erase(key);
         }
 
-        /// add to iterator
-        json_reverse_iterator operator+(difference_type i) const
-        {
-            auto result = *this;
-            result += i;
-            return result;
-        }
+        JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
+    }
 
-        /// subtract from iterator
-        json_reverse_iterator operator-(difference_type i) const
-        {
-            auto result = *this;
-            result -= i;
-            return result;
-        }
+    /*!
+    @brief remove element from a JSON array given an index
+
+    Removes element from a JSON array at the index @a idx.
+
+    @param[in] idx index of the element to remove
+
+    @throw type_error.307 when called on a type other than JSON object;
+    example: `"cannot use erase() with null"`
+    @throw out_of_range.401 when `idx >= size()`; example: `"array index 17
+    is out of range"`
+
+    @complexity Linear in distance between @a idx and the end of the container.
 
-        /// return difference
-        difference_type operator-(const json_reverse_iterator& other) const
+    @liveexample{The example shows the effect of `erase()`.,erase__size_type}
+
+    @sa @ref erase(IteratorType) -- removes the element at a given position
+    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
+    the given range
+    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    from an object at the given key
+
+    @since version 1.0.0
+    */
+    void erase(const size_type idx)
+    {
+        // this erase only works for arrays
+        if (JSON_LIKELY(is_array()))
         {
-            return this->base() - other.base();
-        }
+            if (JSON_UNLIKELY(idx >= size()))
+            {
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
+            }
 
-        /// access to successor
-        reference operator[](difference_type n) const
+            m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
+        }
+        else
         {
-            return *(this->operator+(n));
+            JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
         }
+    }
+
+    /// @}
+
+
+    ////////////
+    // lookup //
+    ////////////
+
+    /// @name lookup
+    /// @{
+
+    /*!
+    @brief find an element in a JSON object
+
+    Finds an element in a JSON object with key equivalent to @a key. If the
+    element is not found or the JSON value is not an object, end() is
+    returned.
+
+    @note This method always returns @ref end() when executed on a JSON type
+          that is not an object.
+
+    @param[in] key key value of the element to search for.
+
+    @return Iterator to an element with key equivalent to @a key. If no such
+    element is found or the JSON value is not an object, past-the-end (see
+    @ref end()) iterator is returned.
+
+    @complexity Logarithmic in the size of the JSON object.
 
-        /// return the key of an object iterator
-        typename object_t::key_type key() const
+    @liveexample{The example shows how `find()` is used.,find__key_type}
+
+    @since version 1.0.0
+    */
+    template<typename KeyT>
+    iterator find(KeyT&& key)
+    {
+        auto result = end();
+
+        if (is_object())
         {
-            auto it = --this->base();
-            return it.key();
+            result.m_it.object_iterator = m_value.object->find(std::forward<KeyT>(key));
         }
 
-        /// return the value of an iterator
-        reference value() const
+        return result;
+    }
+
+    /*!
+    @brief find an element in a JSON object
+    @copydoc find(KeyT&&)
+    */
+    template<typename KeyT>
+    const_iterator find(KeyT&& key) const
+    {
+        auto result = cend();
+
+        if (is_object())
         {
-            auto it = --this->base();
-            return it.operator * ();
+            result.m_it.object_iterator = m_value.object->find(std::forward<KeyT>(key));
         }
-    };
-
 
-  private:
-    //////////////////////
-    // lexer and parser //
-    //////////////////////
+        return result;
+    }
 
     /*!
-    @brief lexical analysis
+    @brief returns the number of occurrences of a key in a JSON object
+
+    Returns the number of elements with key @a key. If ObjectType is the
+    default `std::map` type, the return value will always be `0` (@a key was
+    not found) or `1` (@a key was found).
+
+    @note This method always returns `0` when executed on a JSON type that is
+          not an object.
+
+    @param[in] key key value of the element to count
+
+    @return Number of elements with key @a key. If the JSON value is not an
+    object, the return value will be `0`.
+
+    @complexity Logarithmic in the size of the JSON object.
 
-    This class organizes the lexical analysis during JSON deserialization. The
-    core of it is a scanner generated by [re2c](http://re2c.org) that
-    processes a buffer and recognizes tokens according to RFC 7159.
+    @liveexample{The example shows how `count()` is used.,count}
+
+    @since version 1.0.0
     */
-    class lexer
+    template<typename KeyT>
+    size_type count(KeyT&& key) const
     {
-      public:
-        /// token types for the parser
-        enum class token_type
-        {
-            uninitialized,   ///< indicating the scanner is uninitialized
-            literal_true,    ///< the `true` literal
-            literal_false,   ///< the `false` literal
-            literal_null,    ///< the `null` literal
-            value_string,    ///< a string -- use get_string() for actual value
-            value_unsigned,  ///< an unsigned integer -- use get_number() for actual value
-            value_integer,   ///< a signed integer -- use get_number() for actual value
-            value_float,     ///< an floating point number -- use get_number() for actual value
-            begin_array,     ///< the character for array begin `[`
-            begin_object,    ///< the character for object begin `{`
-            end_array,       ///< the character for array end `]`
-            end_object,      ///< the character for object end `}`
-            name_separator,  ///< the name separator `:`
-            value_separator, ///< the value separator `,`
-            parse_error,     ///< indicating a parse error
-            end_of_input     ///< indicating the end of the input buffer
-        };
+        // return 0 for all nonobject types
+        return is_object() ? m_value.object->count(std::forward<KeyT>(key)) : 0;
+    }
 
-        /// the char type to use in the lexer
-        using lexer_char_t = unsigned char;
+    /// @}
 
-        /// a lexer from a buffer with given length
-        lexer(const lexer_char_t* buff, const size_t len) noexcept
-            : m_content(buff)
-        {
-            assert(m_content != nullptr);
-            m_start = m_cursor = m_content;
-            m_limit = m_content + len;
-        }
 
-        /*!
-        @brief a lexer from an input stream
-        @throw parse_error.111 if input stream is in a bad state
-        */
-        explicit lexer(std::istream& s)
-            : m_stream(&s), m_line_buffer()
-        {
-            // immediately abort if stream is erroneous
-            if (s.fail())
-            {
-                JSON_THROW(parse_error::create(111, 0, "bad input stream"));
-            }
+    ///////////////
+    // iterators //
+    ///////////////
 
-            // fill buffer
-            fill_line_buffer();
+    /// @name iterators
+    /// @{
 
-            // skip UTF-8 byte-order mark
-            if (m_line_buffer.size() >= 3 and m_line_buffer.substr(0, 3) == "\xEF\xBB\xBF")
-            {
-                m_line_buffer[0] = ' ';
-                m_line_buffer[1] = ' ';
-                m_line_buffer[2] = ' ';
-            }
-        }
+    /*!
+    @brief returns an iterator to the first element
 
-        // switch off unwanted functions (due to pointer members)
-        lexer() = delete;
-        lexer(const lexer&) = delete;
-        lexer operator=(const lexer&) = delete;
+    Returns an iterator to the first element.
 
-        /*!
-        @brief create a string from one or two Unicode code points
+    @image html range-begin-end.svg "Illustration from cppreference.com"
 
-        There are two cases: (1) @a codepoint1 is in the Basic Multilingual
-        Plane (U+0000 through U+FFFF) and @a codepoint2 is 0, or (2)
-        @a codepoint1 and @a codepoint2 are a UTF-16 surrogate pair to
-        represent a code point above U+FFFF.
+    @return iterator to the first element
 
-        @param[in] codepoint1  the code point (can be high surrogate)
-        @param[in] codepoint2  the code point (can be low surrogate or 0)
+    @complexity Constant.
 
-        @return string representation of the code point; the length of the
-        result string is between 1 and 4 characters.
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
 
-        @throw parse_error.102 if the low surrogate is invalid; example:
-        `""missing or wrong low surrogate""`
-        @throw parse_error.103 if code point is > 0x10ffff; example: `"code
-        points above 0x10FFFF are invalid"`
+    @liveexample{The following code shows an example for `begin()`.,begin}
 
-        @complexity Constant.
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref cend() -- returns a const iterator to the end
 
-        @see <http://en.wikipedia.org/wiki/UTF-8#Sample_code>
-        */
-        string_t to_unicode(const std::size_t codepoint1,
-                            const std::size_t codepoint2 = 0) const
-        {
-            // calculate the code point from the given code points
-            std::size_t codepoint = codepoint1;
+    @since version 1.0.0
+    */
+    iterator begin() noexcept
+    {
+        iterator result(this);
+        result.set_begin();
+        return result;
+    }
 
-            // check if codepoint1 is a high surrogate
-            if (codepoint1 >= 0xD800 and codepoint1 <= 0xDBFF)
-            {
-                // check if codepoint2 is a low surrogate
-                if (codepoint2 >= 0xDC00 and codepoint2 <= 0xDFFF)
-                {
-                    codepoint =
-                        // high surrogate occupies the most significant 22 bits
-                        (codepoint1 << 10)
-                        // low surrogate occupies the least significant 15 bits
-                        + codepoint2
-                        // there is still the 0xD800, 0xDC00 and 0x10000 noise
-                        // in the result so we have to subtract with:
-                        // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
-                        - 0x35FDC00;
-                }
-                else
-                {
-                    JSON_THROW(parse_error::create(102, get_position(), "missing or wrong low surrogate"));
-                }
-            }
+    /*!
+    @copydoc basic_json::cbegin()
+    */
+    const_iterator begin() const noexcept
+    {
+        return cbegin();
+    }
 
-            string_t result;
+    /*!
+    @brief returns a const iterator to the first element
 
-            if (codepoint < 0x80)
-            {
-                // 1-byte characters: 0xxxxxxx (ASCII)
-                result.append(1, static_cast<typename string_t::value_type>(codepoint));
-            }
-            else if (codepoint <= 0x7ff)
-            {
-                // 2-byte characters: 110xxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xC0 | (codepoint >> 6)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else if (codepoint <= 0xffff)
-            {
-                // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xE0 | (codepoint >> 12)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else if (codepoint <= 0x10ffff)
-            {
-                // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
-                result.append(1, static_cast<typename string_t::value_type>(0xF0 | (codepoint >> 18)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 12) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F)));
-                result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F)));
-            }
-            else
-            {
-                JSON_THROW(parse_error::create(103, get_position(), "code points above 0x10FFFF are invalid"));
-            }
+    Returns a const iterator to the first element.
 
-            return result;
-        }
+    @image html range-begin-end.svg "Illustration from cppreference.com"
 
-        /// return name of values of type token_type (only used for errors)
-        static std::string token_type_name(const token_type t)
-        {
-            switch (t)
-            {
-                case token_type::uninitialized:
-                    return "<uninitialized>";
-                case token_type::literal_true:
-                    return "true literal";
-                case token_type::literal_false:
-                    return "false literal";
-                case token_type::literal_null:
-                    return "null literal";
-                case token_type::value_string:
-                    return "string literal";
-                case lexer::token_type::value_unsigned:
-                case lexer::token_type::value_integer:
-                case lexer::token_type::value_float:
-                    return "number literal";
-                case token_type::begin_array:
-                    return "'['";
-                case token_type::begin_object:
-                    return "'{'";
-                case token_type::end_array:
-                    return "']'";
-                case token_type::end_object:
-                    return "'}'";
-                case token_type::name_separator:
-                    return "':'";
-                case token_type::value_separator:
-                    return "','";
-                case token_type::parse_error:
-                    return "<parse error>";
-                case token_type::end_of_input:
-                    return "end of input";
-                default:
-                {
-                    // catch non-enum values
-                    return "unknown token"; // LCOV_EXCL_LINE
-                }
-            }
-        }
+    @return const iterator to the first element
 
-        /*!
-        This function implements a scanner for JSON. It is specified using
-        regular expressions that try to follow RFC 7159 as close as possible.
-        These regular expressions are then translated into a minimized
-        deterministic finite automaton (DFA) by the tool
-        [re2c](http://re2c.org). As a result, the translated code for this
-        function consists of a large block of code with `goto` jumps.
+    @complexity Constant.
 
-        @return the class of the next token read from the buffer
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).begin()`.
 
-        @complexity Linear in the length of the input.\n
+    @liveexample{The following code shows an example for `cbegin()`.,cbegin}
 
-        Proposition: The loop below will always terminate for finite input.\n
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref cend() -- returns a const iterator to the end
 
-        Proof (by contradiction): Assume a finite input. To loop forever, the
-        loop must never hit code with a `break` statement. The only code
-        snippets without a `break` statement is the continue statement for
-        whitespace. To loop forever, the input must be an infinite sequence
-        whitespace. This contradicts the assumption of finite input, q.e.d.
-        */
-        token_type scan()
-        {
-            while (true)
-            {
-                // pointer for backtracking information
-                m_marker = nullptr;
+    @since version 1.0.0
+    */
+    const_iterator cbegin() const noexcept
+    {
+        const_iterator result(this);
+        result.set_begin();
+        return result;
+    }
 
-                // remember the begin of the token
-                m_start = m_cursor;
-                assert(m_start != nullptr);
+    /*!
+    @brief returns an iterator to one past the last element
 
+    Returns an iterator to one past the last element.
 
-                {
-                    lexer_char_t yych;
-                    unsigned int yyaccept = 0;
-                    static const unsigned char yybm[] =
-                    {
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,  32,  32,   0,   0,  32,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        160, 128,   0, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        192, 192, 192, 192, 192, 192, 192, 192,
-                        192, 192, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128,   0, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        128, 128, 128, 128, 128, 128, 128, 128,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                        0,   0,   0,   0,   0,   0,   0,   0,
-                    };
-                    if ((m_limit - m_cursor) < 5)
-                    {
-                        fill_line_buffer(5);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 32)
-                    {
-                        goto basic_json_parser_6;
-                    }
-                    if (yych <= '[')
-                    {
-                        if (yych <= '-')
-                        {
-                            if (yych <= '"')
-                            {
-                                if (yych <= 0x00)
-                                {
-                                    goto basic_json_parser_2;
-                                }
-                                if (yych <= '!')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_9;
-                            }
-                            else
-                            {
-                                if (yych <= '+')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                if (yych <= ',')
-                                {
-                                    goto basic_json_parser_10;
-                                }
-                                goto basic_json_parser_12;
-                            }
-                        }
-                        else
-                        {
-                            if (yych <= '9')
-                            {
-                                if (yych <= '/')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                if (yych <= '0')
-                                {
-                                    goto basic_json_parser_13;
-                                }
-                                goto basic_json_parser_15;
-                            }
-                            else
-                            {
-                                if (yych <= ':')
-                                {
-                                    goto basic_json_parser_17;
-                                }
-                                if (yych <= 'Z')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_19;
-                            }
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'n')
-                        {
-                            if (yych <= 'e')
-                            {
-                                if (yych == ']')
-                                {
-                                    goto basic_json_parser_21;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                            else
-                            {
-                                if (yych <= 'f')
-                                {
-                                    goto basic_json_parser_23;
-                                }
-                                if (yych <= 'm')
-                                {
-                                    goto basic_json_parser_4;
-                                }
-                                goto basic_json_parser_24;
-                            }
-                        }
-                        else
-                        {
-                            if (yych <= 'z')
-                            {
-                                if (yych == 't')
-                                {
-                                    goto basic_json_parser_25;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                            else
-                            {
-                                if (yych <= '{')
-                                {
-                                    goto basic_json_parser_26;
-                                }
-                                if (yych == '}')
-                                {
-                                    goto basic_json_parser_28;
-                                }
-                                goto basic_json_parser_4;
-                            }
-                        }
-                    }
-basic_json_parser_2:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_of_input;
-                        break;
-                    }
-basic_json_parser_4:
-                    ++m_cursor;
-basic_json_parser_5:
-                    {
-                        last_token_type = token_type::parse_error;
-                        break;
-                    }
-basic_json_parser_6:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 32)
-                    {
-                        goto basic_json_parser_6;
-                    }
-                    {
-                        position += static_cast<size_t>((m_cursor - m_start));
-                        continue;
-                    }
-basic_json_parser_9:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych <= 0x1F)
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    if (yych <= 0x7F)
-                    {
-                        goto basic_json_parser_31;
-                    }
-                    if (yych <= 0xC1)
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    if (yych <= 0xF4)
-                    {
-                        goto basic_json_parser_31;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_10:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::value_separator;
-                        break;
-                    }
-basic_json_parser_12:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_5;
-                    }
-                    if (yych <= '0')
-                    {
-                        goto basic_json_parser_43;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_45;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_13:
-                    yyaccept = 1;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych <= '9')
-                    {
-                        if (yych == '.')
-                        {
-                            goto basic_json_parser_47;
-                        }
-                        if (yych >= '0')
-                        {
-                            goto basic_json_parser_48;
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            if (yych >= 'E')
-                            {
-                                goto basic_json_parser_51;
-                            }
-                        }
-                        else
-                        {
-                            if (yych == 'e')
-                            {
-                                goto basic_json_parser_51;
-                            }
-                        }
-                    }
-basic_json_parser_14:
-                    {
-                        last_token_type = token_type::value_unsigned;
-                        break;
-                    }
-basic_json_parser_15:
-                    yyaccept = 1;
-                    m_marker = ++m_cursor;
-                    if ((m_limit - m_cursor) < 3)
-                    {
-                        fill_line_buffer(3);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yybm[0 + yych] & 64)
-                    {
-                        goto basic_json_parser_15;
-                    }
-                    if (yych <= 'D')
-                    {
-                        if (yych == '.')
-                        {
-                            goto basic_json_parser_47;
-                        }
-                        goto basic_json_parser_14;
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            goto basic_json_parser_51;
-                        }
-                        if (yych == 'e')
-                        {
-                            goto basic_json_parser_51;
-                        }
-                        goto basic_json_parser_14;
-                    }
-basic_json_parser_17:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::name_separator;
-                        break;
-                    }
-basic_json_parser_19:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::begin_array;
-                        break;
-                    }
-basic_json_parser_21:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_array;
-                        break;
-                    }
-basic_json_parser_23:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'a')
-                    {
-                        goto basic_json_parser_52;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_24:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'u')
-                    {
-                        goto basic_json_parser_53;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_25:
-                    yyaccept = 0;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych == 'r')
-                    {
-                        goto basic_json_parser_54;
-                    }
-                    goto basic_json_parser_5;
-basic_json_parser_26:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::begin_object;
-                        break;
-                    }
-basic_json_parser_28:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::end_object;
-                        break;
-                    }
-basic_json_parser_30:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-basic_json_parser_31:
-                    if (yybm[0 + yych] & 128)
-                    {
-                        goto basic_json_parser_30;
-                    }
-                    if (yych <= 0xE0)
-                    {
-                        if (yych <= '\\')
-                        {
-                            if (yych <= 0x1F)
-                            {
-                                goto basic_json_parser_32;
-                            }
-                            if (yych <= '"')
-                            {
-                                goto basic_json_parser_33;
-                            }
-                            goto basic_json_parser_35;
-                        }
-                        else
-                        {
-                            if (yych <= 0xC1)
-                            {
-                                goto basic_json_parser_32;
-                            }
-                            if (yych <= 0xDF)
-                            {
-                                goto basic_json_parser_36;
-                            }
-                            goto basic_json_parser_37;
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 0xEF)
-                        {
-                            if (yych == 0xED)
-                            {
-                                goto basic_json_parser_39;
-                            }
-                            goto basic_json_parser_38;
-                        }
-                        else
-                        {
-                            if (yych <= 0xF0)
-                            {
-                                goto basic_json_parser_40;
-                            }
-                            if (yych <= 0xF3)
-                            {
-                                goto basic_json_parser_41;
-                            }
-                            if (yych <= 0xF4)
-                            {
-                                goto basic_json_parser_42;
-                            }
-                        }
-                    }
-basic_json_parser_32:
-                    m_cursor = m_marker;
-                    if (yyaccept <= 1)
-                    {
-                        if (yyaccept == 0)
-                        {
-                            goto basic_json_parser_5;
-                        }
-                        else
-                        {
-                            goto basic_json_parser_14;
-                        }
-                    }
-                    else
-                    {
-                        if (yyaccept == 2)
-                        {
-                            goto basic_json_parser_44;
-                        }
-                        else
-                        {
-                            goto basic_json_parser_58;
-                        }
-                    }
-basic_json_parser_33:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::value_string;
-                        break;
-                    }
-basic_json_parser_35:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 'e')
-                    {
-                        if (yych <= '/')
-                        {
-                            if (yych == '"')
-                            {
-                                goto basic_json_parser_30;
-                            }
-                            if (yych <= '.')
-                            {
-                                goto basic_json_parser_32;
-                            }
-                            goto basic_json_parser_30;
-                        }
-                        else
-                        {
-                            if (yych <= '\\')
-                            {
-                                if (yych <= '[')
-                                {
-                                    goto basic_json_parser_32;
-                                }
-                                goto basic_json_parser_30;
-                            }
-                            else
-                            {
-                                if (yych == 'b')
-                                {
-                                    goto basic_json_parser_30;
-                                }
-                                goto basic_json_parser_32;
-                            }
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'q')
-                        {
-                            if (yych <= 'f')
-                            {
-                                goto basic_json_parser_30;
-                            }
-                            if (yych == 'n')
-                            {
-                                goto basic_json_parser_30;
-                            }
-                            goto basic_json_parser_32;
-                        }
-                        else
-                        {
-                            if (yych <= 's')
-                            {
-                                if (yych <= 'r')
-                                {
-                                    goto basic_json_parser_30;
-                                }
-                                goto basic_json_parser_32;
-                            }
-                            else
-                            {
-                                if (yych <= 't')
-                                {
-                                    goto basic_json_parser_30;
-                                }
-                                if (yych <= 'u')
-                                {
-                                    goto basic_json_parser_55;
-                                }
-                                goto basic_json_parser_32;
-                            }
-                        }
-                    }
-basic_json_parser_36:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 0x7F)
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= 0xBF)
-                    {
-                        goto basic_json_parser_30;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_37:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 0x9F)
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= 0xBF)
-                    {
-                        goto basic_json_parser_36;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_38:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 0x7F)
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= 0xBF)
-                    {
-                        goto basic_json_parser_36;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_39:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 0x7F)
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= 0x9F)
-                    {
-                        goto basic_json_parser_36;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_40:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 0x8F)
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= 0xBF)
-                    {
-                        goto basic_json_parser_38;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_41:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 0x7F)
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= 0xBF)
-                    {
-                        goto basic_json_parser_38;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_42:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 0x7F)
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= 0x8F)
-                    {
-                        goto basic_json_parser_38;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_43:
-                    yyaccept = 2;
-                    yych = *(m_marker = ++m_cursor);
-                    if (yych <= '9')
-                    {
-                        if (yych == '.')
-                        {
-                            goto basic_json_parser_47;
-                        }
-                        if (yych >= '0')
-                        {
-                            goto basic_json_parser_48;
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            if (yych >= 'E')
-                            {
-                                goto basic_json_parser_51;
-                            }
-                        }
-                        else
-                        {
-                            if (yych == 'e')
-                            {
-                                goto basic_json_parser_51;
-                            }
-                        }
-                    }
-basic_json_parser_44:
-                    {
-                        last_token_type = token_type::value_integer;
-                        break;
-                    }
-basic_json_parser_45:
-                    yyaccept = 2;
-                    m_marker = ++m_cursor;
-                    if ((m_limit - m_cursor) < 3)
-                    {
-                        fill_line_buffer(3);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '9')
-                    {
-                        if (yych == '.')
-                        {
-                            goto basic_json_parser_47;
-                        }
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_44;
-                        }
-                        goto basic_json_parser_45;
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            if (yych <= 'D')
-                            {
-                                goto basic_json_parser_44;
-                            }
-                            goto basic_json_parser_51;
-                        }
-                        else
-                        {
-                            if (yych == 'e')
-                            {
-                                goto basic_json_parser_51;
-                            }
-                            goto basic_json_parser_44;
-                        }
-                    }
-basic_json_parser_47:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_56;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_48:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_50;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_48;
-                    }
-basic_json_parser_50:
-                    {
-                        last_token_type = token_type::parse_error;
-                        break;
-                    }
-basic_json_parser_51:
-                    yych = *++m_cursor;
-                    if (yych <= ',')
-                    {
-                        if (yych == '+')
-                        {
-                            goto basic_json_parser_59;
-                        }
-                        goto basic_json_parser_32;
-                    }
-                    else
-                    {
-                        if (yych <= '-')
-                        {
-                            goto basic_json_parser_59;
-                        }
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_60;
-                        }
-                        goto basic_json_parser_32;
-                    }
-basic_json_parser_52:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_62;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_53:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_63;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_54:
-                    yych = *++m_cursor;
-                    if (yych == 'u')
-                    {
-                        goto basic_json_parser_64;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_55:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_65;
-                        }
-                        goto basic_json_parser_32;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_65;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_65;
-                        }
-                        goto basic_json_parser_32;
-                    }
-basic_json_parser_56:
-                    yyaccept = 3;
-                    m_marker = ++m_cursor;
-                    if ((m_limit - m_cursor) < 3)
-                    {
-                        fill_line_buffer(3);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= 'D')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_58;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_56;
-                        }
-                    }
-                    else
-                    {
-                        if (yych <= 'E')
-                        {
-                            goto basic_json_parser_51;
-                        }
-                        if (yych == 'e')
-                        {
-                            goto basic_json_parser_51;
-                        }
-                    }
-basic_json_parser_58:
-                    {
-                        last_token_type = token_type::value_float;
-                        break;
-                    }
-basic_json_parser_59:
-                    yych = *++m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_32;
-                    }
-                    if (yych >= ':')
-                    {
-                        goto basic_json_parser_32;
-                    }
-basic_json_parser_60:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '/')
-                    {
-                        goto basic_json_parser_58;
-                    }
-                    if (yych <= '9')
-                    {
-                        goto basic_json_parser_60;
-                    }
-                    goto basic_json_parser_58;
-basic_json_parser_62:
-                    yych = *++m_cursor;
-                    if (yych == 's')
-                    {
-                        goto basic_json_parser_66;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_63:
-                    yych = *++m_cursor;
-                    if (yych == 'l')
-                    {
-                        goto basic_json_parser_67;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_64:
-                    yych = *++m_cursor;
-                    if (yych == 'e')
-                    {
-                        goto basic_json_parser_69;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_65:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_71;
-                        }
-                        goto basic_json_parser_32;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_71;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_71;
-                        }
-                        goto basic_json_parser_32;
-                    }
-basic_json_parser_66:
-                    yych = *++m_cursor;
-                    if (yych == 'e')
-                    {
-                        goto basic_json_parser_72;
-                    }
-                    goto basic_json_parser_32;
-basic_json_parser_67:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_null;
-                        break;
-                    }
-basic_json_parser_69:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_true;
-                        break;
-                    }
-basic_json_parser_71:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_74;
-                        }
-                        goto basic_json_parser_32;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_74;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_74;
-                        }
-                        goto basic_json_parser_32;
-                    }
-basic_json_parser_72:
-                    ++m_cursor;
-                    {
-                        last_token_type = token_type::literal_false;
-                        break;
-                    }
-basic_json_parser_74:
-                    ++m_cursor;
-                    if (m_limit <= m_cursor)
-                    {
-                        fill_line_buffer(1);    // LCOV_EXCL_LINE
-                    }
-                    yych = *m_cursor;
-                    if (yych <= '@')
-                    {
-                        if (yych <= '/')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= '9')
-                        {
-                            goto basic_json_parser_30;
-                        }
-                        goto basic_json_parser_32;
-                    }
-                    else
-                    {
-                        if (yych <= 'F')
-                        {
-                            goto basic_json_parser_30;
-                        }
-                        if (yych <= '`')
-                        {
-                            goto basic_json_parser_32;
-                        }
-                        if (yych <= 'f')
-                        {
-                            goto basic_json_parser_30;
-                        }
-                        goto basic_json_parser_32;
-                    }
-                }
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return iterator one past the last element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+
+    @liveexample{The following code shows an example for `end()`.,end}
+
+    @sa @ref cend() -- returns a const iterator to the end
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+
+    @since version 1.0.0
+    */
+    iterator end() noexcept
+    {
+        iterator result(this);
+        result.set_end();
+        return result;
+    }
+
+    /*!
+    @copydoc basic_json::cend()
+    */
+    const_iterator end() const noexcept
+    {
+        return cend();
+    }
+
+    /*!
+    @brief returns a const iterator to one past the last element
+
+    Returns a const iterator to one past the last element.
+
+    @image html range-begin-end.svg "Illustration from cppreference.com"
+
+    @return const iterator one past the last element
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).end()`.
+
+    @liveexample{The following code shows an example for `cend()`.,cend}
+
+    @sa @ref end() -- returns an iterator to the end
+    @sa @ref begin() -- returns an iterator to the beginning
+    @sa @ref cbegin() -- returns a const iterator to the beginning
+
+    @since version 1.0.0
+    */
+    const_iterator cend() const noexcept
+    {
+        const_iterator result(this);
+        result.set_end();
+        return result;
+    }
+
+    /*!
+    @brief returns an iterator to the reverse-beginning
+
+    Returns an iterator to the reverse-beginning; that is, the last element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `reverse_iterator(end())`.
+
+    @liveexample{The following code shows an example for `rbegin()`.,rbegin}
+
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref crend() -- returns a const reverse iterator to the end
+
+    @since version 1.0.0
+    */
+    reverse_iterator rbegin() noexcept
+    {
+        return reverse_iterator(end());
+    }
+
+    /*!
+    @copydoc basic_json::crbegin()
+    */
+    const_reverse_iterator rbegin() const noexcept
+    {
+        return crbegin();
+    }
+
+    /*!
+    @brief returns an iterator to the reverse-end
+
+    Returns an iterator to the reverse-end; that is, one before the first
+    element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `reverse_iterator(begin())`.
+
+    @liveexample{The following code shows an example for `rend()`.,rend}
+
+    @sa @ref crend() -- returns a const reverse iterator to the end
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+
+    @since version 1.0.0
+    */
+    reverse_iterator rend() noexcept
+    {
+        return reverse_iterator(begin());
+    }
+
+    /*!
+    @copydoc basic_json::crend()
+    */
+    const_reverse_iterator rend() const noexcept
+    {
+        return crend();
+    }
+
+    /*!
+    @brief returns a const reverse iterator to the last element
+
+    Returns a const iterator to the reverse-beginning; that is, the last
+    element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).rbegin()`.
+
+    @liveexample{The following code shows an example for `crbegin()`.,crbegin}
+
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref crend() -- returns a const reverse iterator to the end
+
+    @since version 1.0.0
+    */
+    const_reverse_iterator crbegin() const noexcept
+    {
+        return const_reverse_iterator(cend());
+    }
+
+    /*!
+    @brief returns a const reverse iterator to one before the first
+
+    Returns a const reverse iterator to the reverse-end; that is, one before
+    the first element.
+
+    @image html range-rbegin-rend.svg "Illustration from cppreference.com"
+
+    @complexity Constant.
+
+    @requirement This function helps `basic_json` satisfying the
+    [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `const_cast<const basic_json&>(*this).rend()`.
+
+    @liveexample{The following code shows an example for `crend()`.,crend}
+
+    @sa @ref rend() -- returns a reverse iterator to the end
+    @sa @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+
+    @since version 1.0.0
+    */
+    const_reverse_iterator crend() const noexcept
+    {
+        return const_reverse_iterator(cbegin());
+    }
+
+  public:
+    /*!
+    @brief wrapper to access iterator member functions in range-based for
+
+    This function allows to access @ref iterator::key() and @ref
+    iterator::value() during range-based for loops. In these loops, a
+    reference to the JSON values is returned, so there is no access to the
+    underlying iterator.
+
+    For loop without iterator_wrapper:
+
+    @code{cpp}
+    for (auto it = j_object.begin(); it != j_object.end(); ++it)
+    {
+        std::cout << "key: " << it.key() << ", value:" << it.value() << '\n';
+    }
+    @endcode
+
+    Range-based for loop without iterator proxy:
+
+    @code{cpp}
+    for (auto it : j_object)
+    {
+        // "it" is of type json::reference and has no key() member
+        std::cout << "value: " << it << '\n';
+    }
+    @endcode
+
+    Range-based for loop with iterator proxy:
+
+    @code{cpp}
+    for (auto it : json::iterator_wrapper(j_object))
+    {
+        std::cout << "key: " << it.key() << ", value:" << it.value() << '\n';
+    }
+    @endcode
+
+    @note When iterating over an array, `key()` will return the index of the
+          element as string (see example).
+
+    @param[in] ref  reference to a JSON value
+    @return iteration proxy object wrapping @a ref with an interface to use in
+            range-based for loops
+
+    @liveexample{The following code shows how the wrapper is used,iterator_wrapper}
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes in the JSON value.
+
+    @complexity Constant.
+
+    @note The name of this function is not yet final and may change in the
+    future.
+    */
+    static iteration_proxy<iterator> iterator_wrapper(reference ref)
+    {
+        return iteration_proxy<iterator>(ref);
+    }
+
+    /*!
+    @copydoc iterator_wrapper(reference)
+    */
+    static iteration_proxy<const_iterator> iterator_wrapper(const_reference ref)
+    {
+        return iteration_proxy<const_iterator>(ref);
+    }
+
+    /// @}
+
+
+    //////////////
+    // capacity //
+    //////////////
+
+    /// @name capacity
+    /// @{
+
+    /*!
+    @brief checks whether the container is empty.
+
+    Checks if a JSON value has no elements (i.e. whether its @ref size is `0`).
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `true`
+            boolean     | `false`
+            string      | `false`
+            number      | `false`
+            object      | result of function `object_t::empty()`
+            array       | result of function `array_t::empty()`
+
+    @liveexample{The following code uses `empty()` to check if a JSON
+    object contains any elements.,empty}
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their `empty()` functions have constant
+    complexity.
+
+    @iterators No changes.
+
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
+
+    @note This function does not return whether a string stored as JSON value
+    is empty - it returns whether the JSON container itself is empty which is
+    false in the case of a string.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `begin() == end()`.
+
+    @sa @ref size() -- returns the number of elements
+
+    @since version 1.0.0
+    */
+    bool empty() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+            {
+                // null values are empty
+                return true;
+            }
+
+            case value_t::array:
+            {
+                // delegate call to array_t::empty()
+                return m_value.array->empty();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::empty()
+                return m_value.object->empty();
+            }
+
+            default:
+            {
+                // all other types are nonempty
+                return false;
+            }
+        }
+    }
+
+    /*!
+    @brief returns the number of elements
+
+    Returns the number of elements in a JSON value.
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `0`
+            boolean     | `1`
+            string      | `1`
+            number      | `1`
+            object      | result of function object_t::size()
+            array       | result of function array_t::size()
+
+    @liveexample{The following code calls `size()` on the different value
+    types.,size}
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their size() functions have constant
+    complexity.
+
+    @iterators No changes.
+
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
+
+    @note This function does not return the length of a string stored as JSON
+    value - it returns the number of elements in the JSON value which is 1 in
+    the case of a string.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of `std::distance(begin(), end())`.
+
+    @sa @ref empty() -- checks whether the container is empty
+    @sa @ref max_size() -- returns the maximal number of elements
+
+    @since version 1.0.0
+    */
+    size_type size() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::null:
+            {
+                // null values are empty
+                return 0;
+            }
+
+            case value_t::array:
+            {
+                // delegate call to array_t::size()
+                return m_value.array->size();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::size()
+                return m_value.object->size();
+            }
+
+            default:
+            {
+                // all other types have size 1
+                return 1;
+            }
+        }
+    }
+
+    /*!
+    @brief returns the maximum possible number of elements
+
+    Returns the maximum number of elements a JSON value is able to hold due to
+    system or library implementation limitations, i.e. `std::distance(begin(),
+    end())` for the JSON value.
+
+    @return The return value depends on the different types and is
+            defined as follows:
+            Value type  | return value
+            ----------- | -------------
+            null        | `0` (same as `size()`)
+            boolean     | `1` (same as `size()`)
+            string      | `1` (same as `size()`)
+            number      | `1` (same as `size()`)
+            object      | result of function `object_t::max_size()`
+            array       | result of function `array_t::max_size()`
+
+    @liveexample{The following code calls `max_size()` on the different value
+    types. Note the output is implementation specific.,max_size}
+
+    @complexity Constant, as long as @ref array_t and @ref object_t satisfy
+    the Container concept; that is, their `max_size()` functions have constant
+    complexity.
+
+    @iterators No changes.
+
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
+
+    @requirement This function helps `basic_json` satisfying the
+    [Container](http://en.cppreference.com/w/cpp/concept/Container)
+    requirements:
+    - The complexity is constant.
+    - Has the semantics of returning `b.size()` where `b` is the largest
+      possible JSON value.
+
+    @sa @ref size() -- returns the number of elements
+
+    @since version 1.0.0
+    */
+    size_type max_size() const noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::array:
+            {
+                // delegate call to array_t::max_size()
+                return m_value.array->max_size();
+            }
+
+            case value_t::object:
+            {
+                // delegate call to object_t::max_size()
+                return m_value.object->max_size();
+            }
+
+            default:
+            {
+                // all other types have max_size() == size()
+                return size();
+            }
+        }
+    }
+
+    /// @}
+
+
+    ///////////////
+    // modifiers //
+    ///////////////
+
+    /// @name modifiers
+    /// @{
+
+    /*!
+    @brief clears the contents
+
+    Clears the content of a JSON value and resets it to the default value as
+    if @ref basic_json(value_t) would have been called with the current value
+    type from @ref type():
+
+    Value type  | initial value
+    ----------- | -------------
+    null        | `null`
+    boolean     | `false`
+    string      | `""`
+    number      | `0`
+    object      | `{}`
+    array       | `[]`
+
+    @post Has the same effect as calling
+    @code {.cpp}
+    *this = basic_json(type());
+    @endcode
+
+    @liveexample{The example below shows the effect of `clear()` to different
+    JSON types.,clear}
+
+    @complexity Linear in the size of the JSON value.
+
+    @iterators All iterators, pointers and references related to this container
+               are invalidated.
+
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
+
+    @sa @ref basic_json(value_t) -- constructor that creates an object with the
+        same value than calling `clear()`
+
+    @since version 1.0.0
+    */
+    void clear() noexcept
+    {
+        switch (m_type)
+        {
+            case value_t::number_integer:
+            {
+                m_value.number_integer = 0;
+                break;
+            }
+
+            case value_t::number_unsigned:
+            {
+                m_value.number_unsigned = 0;
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                m_value.number_float = 0.0;
+                break;
+            }
+
+            case value_t::boolean:
+            {
+                m_value.boolean = false;
+                break;
+            }
+
+            case value_t::string:
+            {
+                m_value.string->clear();
+                break;
+            }
+
+            case value_t::array:
+            {
+                m_value.array->clear();
+                break;
+            }
+
+            case value_t::object:
+            {
+                m_value.object->clear();
+                break;
+            }
+
+            default:
+                break;
+        }
+    }
+
+    /*!
+    @brief add an object to an array
+
+    Appends the given element @a val to the end of the JSON value. If the
+    function is called on a JSON null value, an empty array is created before
+    appending @a val.
+
+    @param[in] val the value to add to the JSON array
+
+    @throw type_error.308 when called on a type other than JSON array or
+    null; example: `"cannot use push_back() with number"`
+
+    @complexity Amortized constant.
+
+    @liveexample{The example shows how `push_back()` and `+=` can be used to
+    add elements to a JSON array. Note how the `null` value was silently
+    converted to a JSON array.,push_back}
+
+    @since version 1.0.0
+    */
+    void push_back(basic_json&& val)
+    {
+        // push_back only works for null objects or arrays
+        if (JSON_UNLIKELY(not(is_null() or is_array())))
+        {
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
+        }
+
+        // transform null object into an array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value = value_t::array;
+            assert_invariant();
+        }
+
+        // add element to array (move semantics)
+        m_value.array->push_back(std::move(val));
+        // invalidate object
+        val.m_type = value_t::null;
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    reference operator+=(basic_json&& val)
+    {
+        push_back(std::move(val));
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    void push_back(const basic_json& val)
+    {
+        // push_back only works for null objects or arrays
+        if (JSON_UNLIKELY(not(is_null() or is_array())))
+        {
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
+        }
+
+        // transform null object into an array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value = value_t::array;
+            assert_invariant();
+        }
+
+        // add element to array
+        m_value.array->push_back(val);
+    }
+
+    /*!
+    @brief add an object to an array
+    @copydoc push_back(basic_json&&)
+    */
+    reference operator+=(const basic_json& val)
+    {
+        push_back(val);
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an object
+
+    Inserts the given element @a val to the JSON object. If the function is
+    called on a JSON null value, an empty object is created before inserting
+    @a val.
+
+    @param[in] val the value to add to the JSON object
+
+    @throw type_error.308 when called on a type other than JSON object or
+    null; example: `"cannot use push_back() with number"`
+
+    @complexity Logarithmic in the size of the container, O(log(`size()`)).
+
+    @liveexample{The example shows how `push_back()` and `+=` can be used to
+    add elements to a JSON object. Note how the `null` value was silently
+    converted to a JSON object.,push_back__object_t__value}
+
+    @since version 1.0.0
+    */
+    void push_back(const typename object_t::value_type& val)
+    {
+        // push_back only works for null objects or objects
+        if (JSON_UNLIKELY(not(is_null() or is_object())))
+        {
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
+        }
+
+        // transform null object into an object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value = value_t::object;
+            assert_invariant();
+        }
+
+        // add element to array
+        m_value.object->insert(val);
+    }
+
+    /*!
+    @brief add an object to an object
+    @copydoc push_back(const typename object_t::value_type&)
+    */
+    reference operator+=(const typename object_t::value_type& val)
+    {
+        push_back(val);
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an object
+
+    This function allows to use `push_back` with an initializer list. In case
+
+    1. the current value is an object,
+    2. the initializer list @a init contains only two elements, and
+    3. the first element of @a init is a string,
+
+    @a init is converted into an object element and added using
+    @ref push_back(const typename object_t::value_type&). Otherwise, @a init
+    is converted to a JSON value and added using @ref push_back(basic_json&&).
+
+    @param[in] init  an initializer list
+
+    @complexity Linear in the size of the initializer list @a init.
+
+    @note This function is required to resolve an ambiguous overload error,
+          because pairs like `{"key", "value"}` can be both interpreted as
+          `object_t::value_type` or `std::initializer_list<basic_json>`, see
+          https://github.com/nlohmann/json/issues/235 for more information.
+
+    @liveexample{The example shows how initializer lists are treated as
+    objects when possible.,push_back__initializer_list}
+    */
+    void push_back(initializer_list_t init)
+    {
+        if (is_object() and init.size() == 2 and (*init.begin())->is_string())
+        {
+            basic_json&& key = init.begin()->moved_or_copied();
+            push_back(typename object_t::value_type(
+                          std::move(key.get_ref<string_t&>()), (init.begin() + 1)->moved_or_copied()));
+        }
+        else
+        {
+            push_back(basic_json(init));
+        }
+    }
+
+    /*!
+    @brief add an object to an object
+    @copydoc push_back(initializer_list_t)
+    */
+    reference operator+=(initializer_list_t init)
+    {
+        push_back(init);
+        return *this;
+    }
+
+    /*!
+    @brief add an object to an array
+
+    Creates a JSON value from the passed parameters @a args to the end of the
+    JSON value. If the function is called on a JSON null value, an empty array
+    is created before appending the value created from @a args.
+
+    @param[in] args arguments to forward to a constructor of @ref basic_json
+    @tparam Args compatible types to create a @ref basic_json object
+
+    @throw type_error.311 when called on a type other than JSON array or
+    null; example: `"cannot use emplace_back() with number"`
+
+    @complexity Amortized constant.
+
+    @liveexample{The example shows how `push_back()` can be used to add
+    elements to a JSON array. Note how the `null` value was silently converted
+    to a JSON array.,emplace_back}
+
+    @since version 2.0.8
+    */
+    template<class... Args>
+    void emplace_back(Args&& ... args)
+    {
+        // emplace_back only works for null objects or arrays
+        if (JSON_UNLIKELY(not(is_null() or is_array())))
+        {
+            JSON_THROW(type_error::create(311, "cannot use emplace_back() with " + std::string(type_name())));
+        }
+
+        // transform null object into an array
+        if (is_null())
+        {
+            m_type = value_t::array;
+            m_value = value_t::array;
+            assert_invariant();
+        }
+
+        // add element to array (perfect forwarding)
+        m_value.array->emplace_back(std::forward<Args>(args)...);
+    }
+
+    /*!
+    @brief add an object to an object if key does not exist
+
+    Inserts a new element into a JSON object constructed in-place with the
+    given @a args if there is no element with the key in the container. If the
+    function is called on a JSON null value, an empty object is created before
+    appending the value created from @a args.
+
+    @param[in] args arguments to forward to a constructor of @ref basic_json
+    @tparam Args compatible types to create a @ref basic_json object
+
+    @return a pair consisting of an iterator to the inserted element, or the
+            already-existing element if no insertion happened, and a bool
+            denoting whether the insertion took place.
+
+    @throw type_error.311 when called on a type other than JSON object or
+    null; example: `"cannot use emplace() with number"`
+
+    @complexity Logarithmic in the size of the container, O(log(`size()`)).
+
+    @liveexample{The example shows how `emplace()` can be used to add elements
+    to a JSON object. Note how the `null` value was silently converted to a
+    JSON object. Further note how no value is added if there was already one
+    value stored with the same key.,emplace}
+
+    @since version 2.0.8
+    */
+    template<class... Args>
+    std::pair<iterator, bool> emplace(Args&& ... args)
+    {
+        // emplace only works for null objects or arrays
+        if (JSON_UNLIKELY(not(is_null() or is_object())))
+        {
+            JSON_THROW(type_error::create(311, "cannot use emplace() with " + std::string(type_name())));
+        }
+
+        // transform null object into an object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value = value_t::object;
+            assert_invariant();
+        }
+
+        // add element to array (perfect forwarding)
+        auto res = m_value.object->emplace(std::forward<Args>(args)...);
+        // create result iterator and set iterator to the result of emplace
+        auto it = begin();
+        it.m_it.object_iterator = res.first;
+
+        // return pair of iterator and boolean
+        return {it, res.second};
+    }
+
+    /*!
+    @brief inserts element
+
+    Inserts element @a val before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] val element to insert
+    @return iterator pointing to the inserted @a val.
+
+    @throw type_error.309 if called on JSON values other than arrays;
+    example: `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
+    example: `"iterator does not fit current value"`
+
+    @complexity Constant plus linear in the distance between @a pos and end of
+    the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, const basic_json& val)
+    {
+        // insert only works for arrays
+        if (JSON_LIKELY(is_array()))
+        {
+            // check if iterator pos fits to this JSON value
+            if (JSON_UNLIKELY(pos.m_object != this))
+            {
+                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+            }
+
+            // insert to array and return iterator
+            iterator result(this);
+            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val);
+            return result;
+        }
+
+        JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+    }
+
+    /*!
+    @brief inserts element
+    @copydoc insert(const_iterator, const basic_json&)
+    */
+    iterator insert(const_iterator pos, basic_json&& val)
+    {
+        return insert(pos, val);
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts @a cnt copies of @a val before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] cnt number of copies of @a val to insert
+    @param[in] val element to insert
+    @return iterator pointing to the first element inserted, or @a pos if
+    `cnt==0`
+
+    @throw type_error.309 if called on JSON values other than arrays; example:
+    `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
+    example: `"iterator does not fit current value"`
+
+    @complexity Linear in @a cnt plus linear in the distance between @a pos
+    and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__count}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, size_type cnt, const basic_json& val)
+    {
+        // insert only works for arrays
+        if (JSON_LIKELY(is_array()))
+        {
+            // check if iterator pos fits to this JSON value
+            if (JSON_UNLIKELY(pos.m_object != this))
+            {
+                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+            }
+
+            // insert to array and return iterator
+            iterator result(this);
+            result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
+            return result;
+        }
+
+        JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts elements from range `[first, last)` before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] first begin of the range of elements to insert
+    @param[in] last end of the range of elements to insert
+
+    @throw type_error.309 if called on JSON values other than arrays; example:
+    `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
+    example: `"iterator does not fit current value"`
+    @throw invalid_iterator.210 if @a first and @a last do not belong to the
+    same JSON value; example: `"iterators do not fit"`
+    @throw invalid_iterator.211 if @a first or @a last are iterators into
+    container for which insert is called; example: `"passed iterators may not
+    belong to container"`
+
+    @return iterator pointing to the first element inserted, or @a pos if
+    `first==last`
+
+    @complexity Linear in `std::distance(first, last)` plus linear in the
+    distance between @a pos and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__range}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, const_iterator first, const_iterator last)
+    {
+        // insert only works for arrays
+        if (JSON_UNLIKELY(not is_array()))
+        {
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+        }
+
+        // check if iterator pos fits to this JSON value
+        if (JSON_UNLIKELY(pos.m_object != this))
+        {
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+        }
+
+        // check if range iterators belong to the same JSON object
+        if (JSON_UNLIKELY(first.m_object != last.m_object))
+        {
+            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
+        }
+
+        if (JSON_UNLIKELY(first.m_object == this))
+        {
+            JSON_THROW(invalid_iterator::create(211, "passed iterators may not belong to container"));
+        }
+
+        // insert to array and return iterator
+        iterator result(this);
+        result.m_it.array_iterator = m_value.array->insert(
+                                         pos.m_it.array_iterator,
+                                         first.m_it.array_iterator,
+                                         last.m_it.array_iterator);
+        return result;
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts elements from initializer list @a ilist before iterator @a pos.
+
+    @param[in] pos iterator before which the content will be inserted; may be
+    the end() iterator
+    @param[in] ilist initializer list to insert the values from
+
+    @throw type_error.309 if called on JSON values other than arrays; example:
+    `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if @a pos is not an iterator of *this;
+    example: `"iterator does not fit current value"`
+
+    @return iterator pointing to the first element inserted, or @a pos if
+    `ilist` is empty
+
+    @complexity Linear in `ilist.size()` plus linear in the distance between
+    @a pos and end of the container.
+
+    @liveexample{The example shows how `insert()` is used.,insert__ilist}
+
+    @since version 1.0.0
+    */
+    iterator insert(const_iterator pos, initializer_list_t ilist)
+    {
+        // insert only works for arrays
+        if (JSON_UNLIKELY(not is_array()))
+        {
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+        }
+
+        // check if iterator pos fits to this JSON value
+        if (JSON_UNLIKELY(pos.m_object != this))
+        {
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+        }
+
+        // insert to array and return iterator
+        iterator result(this);
+        result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, ilist.begin(), ilist.end());
+        return result;
+    }
+
+    /*!
+    @brief inserts elements
+
+    Inserts elements from range `[first, last)`.
+
+    @param[in] first begin of the range of elements to insert
+    @param[in] last end of the range of elements to insert
+
+    @throw type_error.309 if called on JSON values other than objects; example:
+    `"cannot use insert() with string"`
+    @throw invalid_iterator.202 if iterator @a first or @a last does does not
+    point to an object; example: `"iterators first and last must point to
+    objects"`
+    @throw invalid_iterator.210 if @a first and @a last do not belong to the
+    same JSON value; example: `"iterators do not fit"`
+
+    @complexity Logarithmic: `O(N*log(size() + N))`, where `N` is the number
+    of elements to insert.
+
+    @liveexample{The example shows how `insert()` is used.,insert__range_object}
+
+    @since version 3.0.0
+    */
+    void insert(const_iterator first, const_iterator last)
+    {
+        // insert only works for objects
+        if (JSON_UNLIKELY(not is_object()))
+        {
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+        }
+
+        // check if range iterators belong to the same JSON object
+        if (JSON_UNLIKELY(first.m_object != last.m_object))
+        {
+            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
+        }
+
+        // passed iterators must belong to objects
+        if (JSON_UNLIKELY(not first.m_object->is_object()))
+        {
+            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects"));
+        }
+
+        m_value.object->insert(first.m_it.object_iterator, last.m_it.object_iterator);
+    }
+
+    /*!
+    @brief updates a JSON object from another object, overwriting existing keys
+
+    Inserts all values from JSON object @a j and overwrites existing keys.
+
+    @param[in] j  JSON object to read values from
+
+    @throw type_error.312 if called on JSON values other than objects; example:
+    `"cannot use update() with string"`
+
+    @complexity O(N*log(size() + N)), where N is the number of elements to
+                insert.
+
+    @liveexample{The example shows how `update()` is used.,update}
+
+    @sa https://docs.python.org/3.6/library/stdtypes.html#dict.update
+
+    @since version 3.0.0
+    */
+    void update(const_reference j)
+    {
+        // implicitly convert null value to an empty object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value.object = create<object_t>();
+            assert_invariant();
+        }
+
+        if (JSON_UNLIKELY(not is_object()))
+        {
+            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name())));
+        }
+        if (JSON_UNLIKELY(not j.is_object()))
+        {
+            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(j.type_name())));
+        }
+
+        for (auto it = j.cbegin(); it != j.cend(); ++it)
+        {
+            m_value.object->operator[](it.key()) = it.value();
+        }
+    }
+
+    /*!
+    @brief updates a JSON object from another object, overwriting existing keys
+
+    Inserts all values from from range `[first, last)` and overwrites existing
+    keys.
+
+    @param[in] first begin of the range of elements to insert
+    @param[in] last end of the range of elements to insert
+
+    @throw type_error.312 if called on JSON values other than objects; example:
+    `"cannot use update() with string"`
+    @throw invalid_iterator.202 if iterator @a first or @a last does does not
+    point to an object; example: `"iterators first and last must point to
+    objects"`
+    @throw invalid_iterator.210 if @a first and @a last do not belong to the
+    same JSON value; example: `"iterators do not fit"`
 
-            }
+    @complexity O(N*log(size() + N)), where N is the number of elements to
+                insert.
 
-            position += static_cast<size_t>((m_cursor - m_start));
-            return last_token_type;
-        }
+    @liveexample{The example shows how `update()` is used__range.,update}
 
-        /*!
-        @brief append data from the stream to the line buffer
+    @sa https://docs.python.org/3.6/library/stdtypes.html#dict.update
 
-        This function is called by the scan() function when the end of the
-        buffer (`m_limit`) is reached and the `m_cursor` pointer cannot be
-        incremented without leaving the limits of the line buffer. Note re2c
-        decides when to call this function.
+    @since version 3.0.0
+    */
+    void update(const_iterator first, const_iterator last)
+    {
+        // implicitly convert null value to an empty object
+        if (is_null())
+        {
+            m_type = value_t::object;
+            m_value.object = create<object_t>();
+            assert_invariant();
+        }
 
-        If the lexer reads from contiguous storage, there is no trailing null
-        byte. Therefore, this function must make sure to add these padding
-        null bytes.
+        if (JSON_UNLIKELY(not is_object()))
+        {
+            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name())));
+        }
 
-        If the lexer reads from an input stream, this function reads the next
-        line of the input.
+        // check if range iterators belong to the same JSON object
+        if (JSON_UNLIKELY(first.m_object != last.m_object))
+        {
+            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
+        }
 
-        @pre
-            p p p p p p u u u u u x . . . . . .
-            ^           ^       ^   ^
-            m_content   m_start |   m_limit
-                                m_cursor
+        // passed iterators must belong to objects
+        if (JSON_UNLIKELY(not first.m_object->is_object()
+                          or not first.m_object->is_object()))
+        {
+            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects"));
+        }
 
-        @post
-            u u u u u x x x x x x x . . . . . .
-            ^       ^               ^
-            |       m_cursor        m_limit
-            m_start
-            m_content
-        */
-        void fill_line_buffer(size_t n = 0)
+        for (auto it = first; it != last; ++it)
         {
-            // if line buffer is used, m_content points to its data
-            assert(m_line_buffer.empty()
-                   or m_content == reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()));
+            m_value.object->operator[](it.key()) = it.value();
+        }
+    }
 
-            // if line buffer is used, m_limit is set past the end of its data
-            assert(m_line_buffer.empty()
-                   or m_limit == m_content + m_line_buffer.size());
+    /*!
+    @brief exchanges the values
 
-            // pointer relationships
-            assert(m_content <= m_start);
-            assert(m_start <= m_cursor);
-            assert(m_cursor <= m_limit);
-            assert(m_marker == nullptr or m_marker  <= m_limit);
+    Exchanges the contents of the JSON value with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
 
-            // number of processed characters (p)
-            const auto num_processed_chars = static_cast<size_t>(m_start - m_content);
-            // offset for m_marker wrt. to m_start
-            const auto offset_marker = (m_marker == nullptr) ? 0 : m_marker - m_start;
-            // number of unprocessed characters (u)
-            const auto offset_cursor = m_cursor - m_start;
+    @param[in,out] other JSON value to exchange the contents with
 
-            // no stream is used or end of file is reached
-            if (m_stream == nullptr or m_stream->eof())
-            {
-                // m_start may or may not be pointing into m_line_buffer at
-                // this point. We trust the standard library to do the right
-                // thing. See http://stackoverflow.com/q/28142011/266378
-                m_line_buffer.assign(m_start, m_limit);
+    @complexity Constant.
 
-                // append n characters to make sure that there is sufficient
-                // space between m_cursor and m_limit
-                m_line_buffer.append(1, '\x00');
-                if (n > 0)
-                {
-                    m_line_buffer.append(n - 1, '\x01');
-                }
-            }
-            else
-            {
-                // delete processed characters from line buffer
-                m_line_buffer.erase(0, num_processed_chars);
-                // read next line from input stream
-                m_line_buffer_tmp.clear();
+    @liveexample{The example below shows how JSON values can be swapped with
+    `swap()`.,swap__reference}
 
-                // check if stream is still good
-                if (m_stream->fail())
-                {
-                    JSON_THROW(parse_error::create(111, 0, "bad input stream"));
-                }
+    @since version 1.0.0
+    */
+    void swap(reference other) noexcept (
+        std::is_nothrow_move_constructible<value_t>::value and
+        std::is_nothrow_move_assignable<value_t>::value and
+        std::is_nothrow_move_constructible<json_value>::value and
+        std::is_nothrow_move_assignable<json_value>::value
+    )
+    {
+        std::swap(m_type, other.m_type);
+        std::swap(m_value, other.m_value);
+        assert_invariant();
+    }
 
-                std::getline(*m_stream, m_line_buffer_tmp, '\n');
+    /*!
+    @brief exchanges the values
 
-                // add line with newline symbol to the line buffer
-                m_line_buffer += m_line_buffer_tmp;
-                m_line_buffer.push_back('\n');
-            }
+    Exchanges the contents of a JSON array with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other array to exchange the contents with
+
+    @throw type_error.310 when JSON value is not an array; example: `"cannot
+    use swap() with string"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how arrays can be swapped with
+    `swap()`.,swap__array_t}
+
+    @since version 1.0.0
+    */
+    void swap(array_t& other)
+    {
+        // swap only works for arrays
+        if (JSON_LIKELY(is_array()))
+        {
+            std::swap(*(m_value.array), other);
+        }
+        else
+        {
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
+        }
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON object with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other object to exchange the contents with
+
+    @throw type_error.310 when JSON value is not an object; example:
+    `"cannot use swap() with string"`
+
+    @complexity Constant.
 
-            // set pointers
-            m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.data());
-            assert(m_content != nullptr);
-            m_start  = m_content;
-            m_marker = m_start + offset_marker;
-            m_cursor = m_start + offset_cursor;
-            m_limit  = m_start + m_line_buffer.size();
+    @liveexample{The example below shows how objects can be swapped with
+    `swap()`.,swap__object_t}
+
+    @since version 1.0.0
+    */
+    void swap(object_t& other)
+    {
+        // swap only works for objects
+        if (JSON_LIKELY(is_object()))
+        {
+            std::swap(*(m_value.object), other);
+        }
+        else
+        {
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
         }
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON string with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other string to exchange the contents with
 
-        /// return string representation of last read token
-        string_t get_token_string() const
+    @throw type_error.310 when JSON value is not a string; example: `"cannot
+    use swap() with boolean"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how strings can be swapped with
+    `swap()`.,swap__string_t}
+
+    @since version 1.0.0
+    */
+    void swap(string_t& other)
+    {
+        // swap only works for strings
+        if (JSON_LIKELY(is_string()))
+        {
+            std::swap(*(m_value.string), other);
+        }
+        else
         {
-            assert(m_start != nullptr);
-            return string_t(reinterpret_cast<typename string_t::const_pointer>(m_start),
-                            static_cast<size_t>(m_cursor - m_start));
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
         }
+    }
+
+    /// @}
+
+  public:
+    //////////////////////////////////////////
+    // lexicographical comparison operators //
+    //////////////////////////////////////////
+
+    /// @name lexicographical comparison operators
+    /// @{
+
+    /*!
+    @brief comparison: equal
+
+    Compares two JSON values for equality according to the following rules:
+    - Two JSON values are equal if (1) they are from the same type and (2)
+      their stored values are the same according to their respective
+      `operator==`.
+    - Integer and floating-point numbers are automatically converted before
+      comparison. Note than two NaN values are always treated as unequal.
+    - Two JSON null values are equal.
+
+    @note Floating-point inside JSON values numbers are compared with
+    `json::number_float_t::operator==` which is `double::operator==` by
+    default. To compare floating-point while respecting an epsilon, an alternative
+    [comparison function](https://github.com/mariokonrad/marnav/blob/master/src/marnav/math/floatingpoint.hpp#L34-#L39)
+    could be used, for instance
+    @code {.cpp}
+    template<typename T, typename = typename std::enable_if<std::is_floating_point<T>::value, T>::type>
+    inline bool is_same(T a, T b, T epsilon = std::numeric_limits<T>::epsilon()) noexcept
+    {
+        return std::abs(a - b) <= epsilon;
+    }
+    @endcode
+
+    @note NaN values never compare equal to themselves or to other NaN values.
+
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether the values @a lhs and @a rhs are equal
+
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
+
+    @complexity Linear.
+
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__equal}
+
+    @since version 1.0.0
+    */
+    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
+    {
+        const auto lhs_type = lhs.type();
+        const auto rhs_type = rhs.type();
+
+        if (lhs_type == rhs_type)
+        {
+            switch (lhs_type)
+            {
+                case value_t::array:
+                    return (*lhs.m_value.array == *rhs.m_value.array);
+
+                case value_t::object:
+                    return (*lhs.m_value.object == *rhs.m_value.object);
+
+                case value_t::null:
+                    return true;
+
+                case value_t::string:
+                    return (*lhs.m_value.string == *rhs.m_value.string);
+
+                case value_t::boolean:
+                    return (lhs.m_value.boolean == rhs.m_value.boolean);
+
+                case value_t::number_integer:
+                    return (lhs.m_value.number_integer == rhs.m_value.number_integer);
 
-        /*!
-        @brief return string value for string tokens
+                case value_t::number_unsigned:
+                    return (lhs.m_value.number_unsigned == rhs.m_value.number_unsigned);
 
-        The function iterates the characters between the opening and closing
-        quotes of the string value. The complete string is the range
-        [m_start,m_cursor). Consequently, we iterate from m_start+1 to
-        m_cursor-1.
+                case value_t::number_float:
+                    return (lhs.m_value.number_float == rhs.m_value.number_float);
 
-        We differentiate two cases:
+                default:
+                    return false;
+            }
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        {
+            return (static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float);
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        {
+            return (lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer));
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        {
+            return (static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float);
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        {
+            return (lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned));
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        {
+            return (static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer);
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        {
+            return (lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned));
+        }
 
-        1. Escaped characters. In this case, a new character is constructed
-           according to the nature of the escape. Some escapes create new
-           characters (e.g., `"\\n"` is replaced by `"\n"`), some are copied
-           as is (e.g., `"\\\\"`). Furthermore, Unicode escapes of the shape
-           `"\\uxxxx"` need special care. In this case, to_unicode takes care
-           of the construction of the values.
-        2. Unescaped characters are copied as is.
+        return false;
+    }
 
-        @pre `m_cursor - m_start >= 2`, meaning the length of the last token
-        is at least 2 bytes which is trivially true for any string (which
-        consists of at least two quotes).
+    /*!
+    @brief comparison: equal
+    @copydoc operator==(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator==(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs == basic_json(rhs));
+    }
 
-            " c1 c2 c3 ... "
-            ^                ^
-            m_start          m_cursor
+    /*!
+    @brief comparison: equal
+    @copydoc operator==(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator==(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) == rhs);
+    }
 
-        @complexity Linear in the length of the string.\n
+    /*!
+    @brief comparison: not equal
 
-        Lemma: The loop body will always terminate.\n
+    Compares two JSON values for inequality by calculating `not (lhs == rhs)`.
 
-        Proof (by contradiction): Assume the loop body does not terminate. As
-        the loop body does not contain another loop, one of the called
-        functions must never return. The called functions are `std::strtoul`
-        and to_unicode. Neither function can loop forever, so the loop body
-        will never loop forever which contradicts the assumption that the loop
-        body does not terminate, q.e.d.\n
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether the values @a lhs and @a rhs are not equal
 
-        Lemma: The loop condition for the for loop is eventually false.\n
+    @complexity Linear.
 
-        Proof (by contradiction): Assume the loop does not terminate. Due to
-        the above lemma, this can only be due to a tautological loop
-        condition; that is, the loop condition i < m_cursor - 1 must always be
-        true. Let x be the change of i for any loop iteration. Then
-        m_start + 1 + x < m_cursor - 1 must hold to loop indefinitely. This
-        can be rephrased to m_cursor - m_start - 2 > x. With the
-        precondition, we x <= 0, meaning that the loop condition holds
-        indefinitely if i is always decreased. However, observe that the value
-        of i is strictly increasing with each iteration, as it is incremented
-        by 1 in the iteration expression and never decremented inside the loop
-        body. Hence, the loop condition will eventually be false which
-        contradicts the assumption that the loop condition is a tautology,
-        q.e.d.
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
 
-        @return string value of current token without opening and closing
-        quotes
-        @throw parse_error.102 if to_unicode fails or surrogate error
-        @throw parse_error.103 if to_unicode fails
-        */
-        string_t get_string() const
-        {
-            assert(m_cursor - m_start >= 2);
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__notequal}
 
-            string_t result;
-            result.reserve(static_cast<size_t>(m_cursor - m_start - 2));
+    @since version 1.0.0
+    */
+    friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs == rhs);
+    }
 
-            // iterate the result between the quotes
-            for (const lexer_char_t* i = m_start + 1; i < m_cursor - 1; ++i)
-            {
-                // find next escape character
-                auto e = std::find(i, m_cursor - 1, '\\');
-                if (e != i)
-                {
-                    // see https://github.com/nlohmann/json/issues/365#issuecomment-262874705
-                    for (auto k = i; k < e; k++)
-                    {
-                        result.push_back(static_cast<typename string_t::value_type>(*k));
-                    }
-                    i = e - 1; // -1 because of ++i
-                }
-                else
-                {
-                    // processing escaped character
-                    // read next character
-                    ++i;
+    /*!
+    @brief comparison: not equal
+    @copydoc operator!=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator!=(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs != basic_json(rhs));
+    }
 
-                    switch (*i)
-                    {
-                        // the default escapes
-                        case 't':
-                        {
-                            result += "\t";
-                            break;
-                        }
-                        case 'b':
-                        {
-                            result += "\b";
-                            break;
-                        }
-                        case 'f':
-                        {
-                            result += "\f";
-                            break;
-                        }
-                        case 'n':
-                        {
-                            result += "\n";
-                            break;
-                        }
-                        case 'r':
-                        {
-                            result += "\r";
-                            break;
-                        }
-                        case '\\':
-                        {
-                            result += "\\";
-                            break;
-                        }
-                        case '/':
-                        {
-                            result += "/";
-                            break;
-                        }
-                        case '"':
-                        {
-                            result += "\"";
-                            break;
-                        }
+    /*!
+    @brief comparison: not equal
+    @copydoc operator!=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator!=(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) != rhs);
+    }
 
-                        // unicode
-                        case 'u':
-                        {
-                            // get code xxxx from uxxxx
-                            auto codepoint = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>(i + 1),
-                                                          4).c_str(), nullptr, 16);
+    /*!
+    @brief comparison: less than
 
-                            // check if codepoint is a high surrogate
-                            if (codepoint >= 0xD800 and codepoint <= 0xDBFF)
-                            {
-                                // make sure there is a subsequent unicode
-                                if ((i + 6 >= m_limit) or * (i + 5) != '\\' or * (i + 6) != 'u')
-                                {
-                                    JSON_THROW(parse_error::create(102, get_position(), "missing low surrogate"));
-                                }
+    Compares whether one JSON value @a lhs is less than another JSON value @a
+    rhs according to the following rules:
+    - If @a lhs and @a rhs have the same type, the values are compared using
+      the default `<` operator.
+    - Integer and floating-point numbers are automatically converted before
+      comparison
+    - In case @a lhs and @a rhs have different types, the values are ignored
+      and the order of the types is considered, see
+      @ref operator<(const value_t, const value_t).
 
-                                // get code yyyy from uxxxx\uyyyy
-                                auto codepoint2 = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>
-                                                               (i + 7), 4).c_str(), nullptr, 16);
-                                result += to_unicode(codepoint, codepoint2);
-                                // skip the next 10 characters (xxxx\uyyyy)
-                                i += 10;
-                            }
-                            else if (codepoint >= 0xDC00 and codepoint <= 0xDFFF)
-                            {
-                                // we found a lone low surrogate
-                                JSON_THROW(parse_error::create(102, get_position(), "missing high surrogate"));
-                            }
-                            else
-                            {
-                                // add unicode character(s)
-                                result += to_unicode(codepoint);
-                                // skip the next four characters (xxxx)
-                                i += 4;
-                            }
-                            break;
-                        }
-                    }
-                }
-            }
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is less than @a rhs
 
-            return result;
-        }
+    @complexity Linear.
 
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
 
-        /*!
-        @brief parse string into a built-in arithmetic type as if the current
-               locale is POSIX.
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__less}
 
-        @note in floating-point case strtod may parse past the token's end -
-              this is not an error
+    @since version 1.0.0
+    */
+    friend bool operator<(const_reference lhs, const_reference rhs) noexcept
+    {
+        const auto lhs_type = lhs.type();
+        const auto rhs_type = rhs.type();
 
-        @note any leading blanks are not handled
-        */
-        struct strtonum
+        if (lhs_type == rhs_type)
         {
-          public:
-            strtonum(const char* start, const char* end)
-                : m_start(start), m_end(end)
-            {}
-
-            /*!
-            @return true iff parsed successfully as number of type T
-
-            @param[in,out] val shall contain parsed value, or undefined value
-            if could not parse
-            */
-            template<typename T, typename = typename std::enable_if<std::is_arithmetic<T>::value>::type>
-            bool to(T& val) const
+            switch (lhs_type)
             {
-                return parse(val, std::is_integral<T>());
-            }
-
-          private:
-            const char* const m_start = nullptr;
-            const char* const m_end = nullptr;
-
-            // floating-point conversion
+                case value_t::array:
+                    return (*lhs.m_value.array) < (*rhs.m_value.array);
 
-            // overloaded wrappers for strtod/strtof/strtold
-            // that will be called from parse<floating_point_t>
-            static void strtof(float& f, const char* str, char** endptr)
-            {
-                f = std::strtof(str, endptr);
-            }
+                case value_t::object:
+                    return *lhs.m_value.object < *rhs.m_value.object;
 
-            static void strtof(double& f, const char* str, char** endptr)
-            {
-                f = std::strtod(str, endptr);
-            }
+                case value_t::null:
+                    return false;
 
-            static void strtof(long double& f, const char* str, char** endptr)
-            {
-                f = std::strtold(str, endptr);
-            }
+                case value_t::string:
+                    return *lhs.m_value.string < *rhs.m_value.string;
 
-            template<typename T>
-            bool parse(T& value, /*is_integral=*/std::false_type) const
-            {
-                // replace decimal separator with locale-specific version,
-                // when necessary; data will point to either the original
-                // string, or buf, or tempstr containing the fixed string.
-                std::string tempstr;
-                std::array<char, 64> buf;
-                const size_t len = static_cast<size_t>(m_end - m_start);
+                case value_t::boolean:
+                    return lhs.m_value.boolean < rhs.m_value.boolean;
 
-                // lexer will reject empty numbers
-                assert(len > 0);
+                case value_t::number_integer:
+                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
 
-                // since dealing with strtod family of functions, we're
-                // getting the decimal point char from the C locale facilities
-                // instead of C++'s numpunct facet of the current std::locale
-                const auto loc = localeconv();
-                assert(loc != nullptr);
-                const char decimal_point_char = (loc->decimal_point == nullptr) ? '.' : loc->decimal_point[0];
+                case value_t::number_unsigned:
+                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
 
-                const char* data = m_start;
+                case value_t::number_float:
+                    return lhs.m_value.number_float < rhs.m_value.number_float;
 
-                if (decimal_point_char != '.')
-                {
-                    const size_t ds_pos = static_cast<size_t>(std::find(m_start, m_end, '.') - m_start);
+                default:
+                    return false;
+            }
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        {
+            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        {
+            return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
+        }
+        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        {
+            return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
+        }
+        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        {
+            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
+        }
 
-                    if (ds_pos != len)
-                    {
-                        // copy the data into the local buffer or tempstr, if
-                        // buffer is too small; replace decimal separator, and
-                        // update data to point to the modified bytes
-                        if ((len + 1) < buf.size())
-                        {
-                            std::copy(m_start, m_end, buf.begin());
-                            buf[len] = 0;
-                            buf[ds_pos] = decimal_point_char;
-                            data = buf.data();
-                        }
-                        else
-                        {
-                            tempstr.assign(m_start, m_end);
-                            tempstr[ds_pos] = decimal_point_char;
-                            data = tempstr.c_str();
-                        }
-                    }
-                }
+        // We only reach this line if we cannot compare values. In that case,
+        // we compare types. Note we have to call the operator explicitly,
+        // because MSVC has problems otherwise.
+        return operator<(lhs_type, rhs_type);
+    }
 
-                char* endptr = nullptr;
-                value = 0;
-                // this calls appropriate overload depending on T
-                strtof(value, data, &endptr);
+    /*!
+    @brief comparison: less than
+    @copydoc operator<(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator<(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs < basic_json(rhs));
+    }
 
-                // parsing was successful iff strtof parsed exactly the number
-                // of characters determined by the lexer (len)
-                const bool ok = (endptr == (data + len));
+    /*!
+    @brief comparison: less than
+    @copydoc operator<(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator<(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) < rhs);
+    }
 
-                if (ok and (value == static_cast<T>(0.0)) and (*data == '-'))
-                {
-                    // some implementations forget to negate the zero
-                    value = -0.0;
-                }
+    /*!
+    @brief comparison: less than or equal
 
-                return ok;
-            }
+    Compares whether one JSON value @a lhs is less than or equal to another
+    JSON value by calculating `not (rhs < lhs)`.
 
-            // integral conversion
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is less than or equal to @a rhs
 
-            signed long long parse_integral(char** endptr, /*is_signed*/std::true_type) const
-            {
-                return std::strtoll(m_start, endptr, 10);
-            }
+    @complexity Linear.
 
-            unsigned long long parse_integral(char** endptr, /*is_signed*/std::false_type) const
-            {
-                return std::strtoull(m_start, endptr, 10);
-            }
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
 
-            template<typename T>
-            bool parse(T& value, /*is_integral=*/std::true_type) const
-            {
-                char* endptr = nullptr;
-                errno = 0; // these are thread-local
-                const auto x = parse_integral(&endptr, std::is_signed<T>());
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__greater}
 
-                // called right overload?
-                static_assert(std::is_signed<T>() == std::is_signed<decltype(x)>(), "");
+    @since version 1.0.0
+    */
+    friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (rhs < lhs);
+    }
 
-                value = static_cast<T>(x);
+    /*!
+    @brief comparison: less than or equal
+    @copydoc operator<=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator<=(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs <= basic_json(rhs));
+    }
 
-                return (x == static_cast<decltype(x)>(value)) // x fits into destination T
-                       and (x < 0) == (value < 0)             // preserved sign
-                       //and ((x != 0) or is_integral())        // strto[u]ll did nto fail
-                       and (errno == 0)                       // strto[u]ll did not overflow
-                       and (m_start < m_end)                  // token was not empty
-                       and (endptr == m_end);                 // parsed entire token exactly
-            }
-        };
+    /*!
+    @brief comparison: less than or equal
+    @copydoc operator<=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator<=(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) <= rhs);
+    }
 
-        /*!
-        @brief return number value for number tokens
+    /*!
+    @brief comparison: greater than
 
-        This function translates the last token into the most appropriate
-        number type (either integer, unsigned integer or floating point),
-        which is passed back to the caller via the result parameter.
+    Compares whether one JSON value @a lhs is greater than another
+    JSON value by calculating `not (lhs <= rhs)`.
 
-        integral numbers that don't fit into the the range of the respective
-        type are parsed as number_float_t
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is greater than to @a rhs
 
-        floating-point values do not satisfy std::isfinite predicate
-        are converted to value_t::null
+    @complexity Linear.
 
-        throws if the entire string [m_start .. m_cursor) cannot be
-        interpreted as a number
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
 
-        @param[out] result  @ref basic_json object to receive the number.
-        @param[in]  token   the type of the number token
-        */
-        bool get_number(basic_json& result, const token_type token) const
-        {
-            assert(m_start != nullptr);
-            assert(m_start < m_cursor);
-            assert((token == token_type::value_unsigned) or
-                   (token == token_type::value_integer) or
-                   (token == token_type::value_float));
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__lessequal}
 
-            strtonum num_converter(reinterpret_cast<const char*>(m_start),
-                                   reinterpret_cast<const char*>(m_cursor));
+    @since version 1.0.0
+    */
+    friend bool operator>(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs <= rhs);
+    }
 
-            switch (token)
-            {
-                case lexer::token_type::value_unsigned:
-                {
-                    number_unsigned_t val;
-                    if (num_converter.to(val))
-                    {
-                        // parsing successful
-                        result.m_type = value_t::number_unsigned;
-                        result.m_value = val;
-                        return true;
-                    }
-                    break;
-                }
+    /*!
+    @brief comparison: greater than
+    @copydoc operator>(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator>(const_reference lhs, const ScalarType rhs) noexcept
+    {
+        return (lhs > basic_json(rhs));
+    }
 
-                case lexer::token_type::value_integer:
-                {
-                    number_integer_t val;
-                    if (num_converter.to(val))
-                    {
-                        // parsing successful
-                        result.m_type = value_t::number_integer;
-                        result.m_value = val;
-                        return true;
-                    }
-                    break;
-                }
+    /*!
+    @brief comparison: greater than
+    @copydoc operator>(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator>(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) > rhs);
+    }
 
-                default:
-                {
-                    break;
-                }
-            }
+    /*!
+    @brief comparison: greater than or equal
 
-            // parse float (either explicitly or because a previous conversion
-            // failed)
-            number_float_t val;
-            if (num_converter.to(val))
-            {
-                // parsing successful
-                result.m_type = value_t::number_float;
-                result.m_value = val;
+    Compares whether one JSON value @a lhs is greater than or equal to another
+    JSON value by calculating `not (lhs < rhs)`.
 
-                // throw in case of infinity or NAN
-                if (not std::isfinite(result.m_value.number_float))
-                {
-                    JSON_THROW(out_of_range::create(406, "number overflow parsing '" + get_token_string() + "'"));
-                }
+    @param[in] lhs  first JSON value to consider
+    @param[in] rhs  second JSON value to consider
+    @return whether @a lhs is greater than or equal to @a rhs
 
-                return true;
-            }
+    @complexity Linear.
 
-            // couldn't parse number in any format
-            return false;
-        }
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
 
-        constexpr size_t get_position() const
-        {
-            return position;
-        }
+    @liveexample{The example demonstrates comparing several JSON
+    types.,operator__greaterequal}
 
-      private:
-        /// optional input stream
-        std::istream* m_stream = nullptr;
-        /// line buffer buffer for m_stream
-        string_t m_line_buffer {};
-        /// used for filling m_line_buffer
-        string_t m_line_buffer_tmp {};
-        /// the buffer pointer
-        const lexer_char_t* m_content = nullptr;
-        /// pointer to the beginning of the current symbol
-        const lexer_char_t* m_start = nullptr;
-        /// pointer for backtracking information
-        const lexer_char_t* m_marker = nullptr;
-        /// pointer to the current symbol
-        const lexer_char_t* m_cursor = nullptr;
-        /// pointer to the end of the buffer
-        const lexer_char_t* m_limit = nullptr;
-        /// the last token type
-        token_type last_token_type = token_type::end_of_input;
-        /// current position in the input (read bytes)
-        size_t position = 0;
-    };
+    @since version 1.0.0
+    */
+    friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
+    {
+        return not (lhs < rhs);
+    }
 
     /*!
-    @brief syntax analysis
-
-    This class implements a recursive decent parser.
+    @brief comparison: greater than or equal
+    @copydoc operator>=(const_reference, const_reference)
     */
-    class parser
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator>=(const_reference lhs, const ScalarType rhs) noexcept
     {
-      public:
-        /// a parser reading from a string literal
-        parser(const char* buff, const parser_callback_t cb = nullptr)
-            : callback(cb),
-              m_lexer(reinterpret_cast<const typename lexer::lexer_char_t*>(buff), std::strlen(buff))
-        {}
-
-        /*!
-        @brief a parser reading from an input stream
-        @throw parse_error.111 if input stream is in a bad state
-        */
-        parser(std::istream& is, const parser_callback_t cb = nullptr)
-            : callback(cb), m_lexer(is)
-        {}
-
-        /// a parser reading from an iterator range with contiguous storage
-        template<class IteratorType, typename std::enable_if<
-                     std::is_same<typename std::iterator_traits<IteratorType>::iterator_category, std::random_access_iterator_tag>::value
-                     , int>::type
-                 = 0>
-        parser(IteratorType first, IteratorType last, const parser_callback_t cb = nullptr)
-            : callback(cb),
-              m_lexer(reinterpret_cast<const typename lexer::lexer_char_t*>(&(*first)),
-                      static_cast<size_t>(std::distance(first, last)))
-        {}
-
-        /*!
-        @brief public parser interface
-        @throw parse_error.101 in case of an unexpected token
-        @throw parse_error.102 if to_unicode fails or surrogate error
-        @throw parse_error.103 if to_unicode fails
-        */
-        basic_json parse()
-        {
-            // read first token
-            get_token();
-
-            basic_json result = parse_internal(true);
-            result.assert_invariant();
+        return (lhs >= basic_json(rhs));
+    }
 
-            expect(lexer::token_type::end_of_input);
+    /*!
+    @brief comparison: greater than or equal
+    @copydoc operator>=(const_reference, const_reference)
+    */
+    template<typename ScalarType, typename std::enable_if<
+                 std::is_scalar<ScalarType>::value, int>::type = 0>
+    friend bool operator>=(const ScalarType lhs, const_reference rhs) noexcept
+    {
+        return (basic_json(lhs) >= rhs);
+    }
 
-            // return parser result and replace it with null in case the
-            // top-level value was discarded by the callback function
-            return result.is_discarded() ? basic_json() : std::move(result);
-        }
+    /// @}
 
-      private:
-        /*!
-        @brief the actual parser
-        @throw parse_error.101 in case of an unexpected token
-        @throw parse_error.102 if to_unicode fails or surrogate error
-        @throw parse_error.103 if to_unicode fails
-        */
-        basic_json parse_internal(bool keep)
-        {
-            auto result = basic_json(value_t::discarded);
+    ///////////////////
+    // serialization //
+    ///////////////////
 
-            switch (last_token)
-            {
-                case lexer::token_type::begin_object:
-                {
-                    if (keep and (not callback
-                                  or ((keep = callback(depth++, parse_event_t::object_start, result)) != 0)))
-                    {
-                        // explicitly set result to object to cope with {}
-                        result.m_type = value_t::object;
-                        result.m_value = value_t::object;
-                    }
+    /// @name serialization
+    /// @{
 
-                    // read next token
-                    get_token();
+    /*!
+    @brief serialize to stream
 
-                    // closing } -> we are done
-                    if (last_token == lexer::token_type::end_object)
-                    {
-                        get_token();
-                        if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
-                        {
-                            result = basic_json(value_t::discarded);
-                        }
-                        return result;
-                    }
+    Serialize the given JSON value @a j to the output stream @a o. The JSON
+    value will be serialized using the @ref dump member function.
 
-                    // no comma is expected here
-                    unexpect(lexer::token_type::value_separator);
+    - The indentation of the output can be controlled with the member variable
+      `width` of the output stream @a o. For instance, using the manipulator
+      `std::setw(4)` on @a o sets the indentation level to `4` and the
+      serialization result is the same as calling `dump(4)`.
 
-                    // otherwise: parse key-value pairs
-                    do
-                    {
-                        // ugly, but could be fixed with loop reorganization
-                        if (last_token == lexer::token_type::value_separator)
-                        {
-                            get_token();
-                        }
+    - The indentation character can be controlled with the member variable
+      `fill` of the output stream @a o. For instance, the manipulator
+      `std::setfill('\\t')` sets indentation to use a tab character rather than
+      the default space character.
 
-                        // store key
-                        expect(lexer::token_type::value_string);
-                        const auto key = m_lexer.get_string();
+    @param[in,out] o  stream to serialize to
+    @param[in] j  JSON value to serialize
 
-                        bool keep_tag = false;
-                        if (keep)
-                        {
-                            if (callback)
-                            {
-                                basic_json k(key);
-                                keep_tag = callback(depth, parse_event_t::key, k);
-                            }
-                            else
-                            {
-                                keep_tag = true;
-                            }
-                        }
+    @return the stream @a o
 
-                        // parse separator (:)
-                        get_token();
-                        expect(lexer::token_type::name_separator);
+    @throw type_error.316 if a string stored inside the JSON value is not
+                          UTF-8 encoded
 
-                        // parse and add value
-                        get_token();
-                        auto value = parse_internal(keep);
-                        if (keep and keep_tag and not value.is_discarded())
-                        {
-                            result[key] = std::move(value);
-                        }
-                    }
-                    while (last_token == lexer::token_type::value_separator);
+    @complexity Linear.
 
-                    // closing }
-                    expect(lexer::token_type::end_object);
-                    get_token();
-                    if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
-                    {
-                        result = basic_json(value_t::discarded);
-                    }
+    @liveexample{The example below shows the serialization with different
+    parameters to `width` to adjust the indentation level.,operator_serialize}
 
-                    return result;
-                }
+    @since version 1.0.0; indentation character added in version 3.0.0
+    */
+    friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
+    {
+        // read width member and use it as indentation parameter if nonzero
+        const bool pretty_print = (o.width() > 0);
+        const auto indentation = (pretty_print ? o.width() : 0);
 
-                case lexer::token_type::begin_array:
-                {
-                    if (keep and (not callback
-                                  or ((keep = callback(depth++, parse_event_t::array_start, result)) != 0)))
-                    {
-                        // explicitly set result to object to cope with []
-                        result.m_type = value_t::array;
-                        result.m_value = value_t::array;
-                    }
+        // reset width to 0 for subsequent calls to this stream
+        o.width(0);
 
-                    // read next token
-                    get_token();
+        // do the actual serialization
+        serializer s(detail::output_adapter<char>(o), o.fill());
+        s.dump(j, pretty_print, false, static_cast<unsigned int>(indentation));
+        return o;
+    }
 
-                    // closing ] -> we are done
-                    if (last_token == lexer::token_type::end_array)
-                    {
-                        get_token();
-                        if (callback and not callback(--depth, parse_event_t::array_end, result))
-                        {
-                            result = basic_json(value_t::discarded);
-                        }
-                        return result;
-                    }
+    /*!
+    @brief serialize to stream
+    @deprecated This stream operator is deprecated and will be removed in a
+                future version of the library. Please use
+                @ref operator<<(std::ostream&, const basic_json&)
+                instead; that is, replace calls like `j >> o;` with `o << j;`.
+    @since version 1.0.0; deprecated since version 3.0.0
+    */
+    JSON_DEPRECATED
+    friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
+    {
+        return o << j;
+    }
 
-                    // no comma is expected here
-                    unexpect(lexer::token_type::value_separator);
+    /// @}
 
-                    // otherwise: parse values
-                    do
-                    {
-                        // ugly, but could be fixed with loop reorganization
-                        if (last_token == lexer::token_type::value_separator)
-                        {
-                            get_token();
-                        }
 
-                        // parse value
-                        auto value = parse_internal(keep);
-                        if (keep and not value.is_discarded())
-                        {
-                            result.push_back(std::move(value));
-                        }
-                    }
-                    while (last_token == lexer::token_type::value_separator);
+    /////////////////////
+    // deserialization //
+    /////////////////////
 
-                    // closing ]
-                    expect(lexer::token_type::end_array);
-                    get_token();
-                    if (keep and callback and not callback(--depth, parse_event_t::array_end, result))
-                    {
-                        result = basic_json(value_t::discarded);
-                    }
+    /// @name deserialization
+    /// @{
 
-                    return result;
-                }
+    /*!
+    @brief deserialize from a compatible input
 
-                case lexer::token_type::literal_null:
-                {
-                    get_token();
-                    result.m_type = value_t::null;
-                    break;
-                }
+    This function reads from a compatible input. Examples are:
+    - an array of 1-byte values
+    - strings with character/literal type with size of 1 byte
+    - input streams
+    - container with contiguous storage of 1-byte values. Compatible container
+      types include `std::vector`, `std::string`, `std::array`,
+      `std::valarray`, and `std::initializer_list`. Furthermore, C-style
+      arrays can be used with `std::begin()`/`std::end()`. User-defined
+      containers can be used as long as they implement random-access iterators
+      and a contiguous storage.
 
-                case lexer::token_type::value_string:
-                {
-                    const auto s = m_lexer.get_string();
-                    get_token();
-                    result = basic_json(s);
-                    break;
-                }
+    @pre Each element of the container has a size of 1 byte. Violating this
+    precondition yields undefined behavior. **This precondition is enforced
+    with a static assertion.**
 
-                case lexer::token_type::literal_true:
-                {
-                    get_token();
-                    result.m_type = value_t::boolean;
-                    result.m_value = true;
-                    break;
-                }
+    @pre The container storage is contiguous. Violating this precondition
+    yields undefined behavior. **This precondition is enforced with an
+    assertion.**
+    @pre Each element of the container has a size of 1 byte. Violating this
+    precondition yields undefined behavior. **This precondition is enforced
+    with a static assertion.**
 
-                case lexer::token_type::literal_false:
-                {
-                    get_token();
-                    result.m_type = value_t::boolean;
-                    result.m_value = false;
-                    break;
-                }
+    @warning There is no way to enforce all preconditions at compile-time. If
+             the function is called with a noncompliant container and with
+             assertions switched off, the behavior is undefined and will most
+             likely yield segmentation violation.
 
-                case lexer::token_type::value_unsigned:
-                case lexer::token_type::value_integer:
-                case lexer::token_type::value_float:
-                {
-                    m_lexer.get_number(result, last_token);
-                    get_token();
-                    break;
-                }
+    @param[in] i  input to read from
+    @param[in] cb  a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
 
-                default:
-                {
-                    // the last token was unexpected
-                    unexpect(last_token);
-                }
-            }
+    @return result of the deserialization
 
-            if (keep and callback and not callback(depth, parse_event_t::value, result))
-            {
-                result = basic_json(value_t::discarded);
-            }
-            return result;
-        }
+    @throw parse_error.101 if a parse error occurs; example: `""unexpected end
+    of input; expected string literal""`
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
 
-        /// get next token from lexer
-        typename lexer::token_type get_token()
-        {
-            last_token = m_lexer.scan();
-            return last_token;
-        }
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
 
-        /*!
-        @throw parse_error.101 if expected token did not occur
-        */
-        void expect(typename lexer::token_type t) const
-        {
-            if (t != last_token)
-            {
-                std::string error_msg = "parse error - unexpected ";
-                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
-                              "'") :
-                              lexer::token_type_name(last_token));
-                error_msg += "; expected " + lexer::token_type_name(t);
-                JSON_THROW(parse_error::create(101, m_lexer.get_position(), error_msg));
-            }
-        }
+    @note A UTF-8 byte order mark is silently ignored.
 
-        /*!
-        @throw parse_error.101 if unexpected token occurred
-        */
-        void unexpect(typename lexer::token_type t) const
-        {
-            if (t == last_token)
-            {
-                std::string error_msg = "parse error - unexpected ";
-                error_msg += (last_token == lexer::token_type::parse_error ? ("'" +  m_lexer.get_token_string() +
-                              "'") :
-                              lexer::token_type_name(last_token));
-                JSON_THROW(parse_error::create(101, m_lexer.get_position(), error_msg));
-            }
-        }
+    @liveexample{The example below demonstrates the `parse()` function reading
+    from an array.,parse__array__parser_callback_t}
 
-      private:
-        /// current level of recursion
-        int depth = 0;
-        /// callback function
-        const parser_callback_t callback = nullptr;
-        /// the type of the last read token
-        typename lexer::token_type last_token = lexer::token_type::uninitialized;
-        /// the lexer
-        lexer m_lexer;
-    };
+    @liveexample{The example below demonstrates the `parse()` function with
+    and without callback function.,parse__string__parser_callback_t}
 
-  public:
-    /*!
-    @brief JSON Pointer
+    @liveexample{The example below demonstrates the `parse()` function with
+    and without callback function.,parse__istream__parser_callback_t}
 
-    A JSON pointer defines a string syntax for identifying a specific value
-    within a JSON document. It can be used with functions `at` and
-    `operator[]`. Furthermore, JSON pointers are the base for JSON patches.
+    @liveexample{The example below demonstrates the `parse()` function reading
+    from a contiguous container.,parse__contiguouscontainer__parser_callback_t}
 
-    @sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
+    @since version 2.0.3 (contiguous containers)
+    */
+    static basic_json parse(detail::input_adapter i,
+                            const parser_callback_t cb = nullptr,
+                            const bool allow_exceptions = true)
+    {
+        basic_json result;
+        parser(i, cb, allow_exceptions).parse(true, result);
+        return result;
+    }
 
-    @since version 2.0.0
+    /*!
+    @copydoc basic_json parse(detail::input_adapter, const parser_callback_t)
     */
-    class json_pointer
+    static basic_json parse(detail::input_adapter& i,
+                            const parser_callback_t cb = nullptr,
+                            const bool allow_exceptions = true)
     {
-        /// allow basic_json to access private members
-        friend class basic_json;
+        basic_json result;
+        parser(i, cb, allow_exceptions).parse(true, result);
+        return result;
+    }
 
-      public:
-        /*!
-        @brief create JSON pointer
+    static bool accept(detail::input_adapter i)
+    {
+        return parser(i).accept(true);
+    }
 
-        Create a JSON pointer according to the syntax described in
-        [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3).
+    static bool accept(detail::input_adapter& i)
+    {
+        return parser(i).accept(true);
+    }
 
-        @param[in] s  string representing the JSON pointer; if omitted, the
-                      empty string is assumed which references the whole JSON
-                      value
+    /*!
+    @brief deserialize from an iterator range with contiguous storage
 
-        @throw parse_error.107 if the given JSON pointer @a s is nonempty and
-        does not begin with a slash (`/`); see example below
+    This function reads from an iterator range of a container with contiguous
+    storage of 1-byte values. Compatible container types include
+    `std::vector`, `std::string`, `std::array`, `std::valarray`, and
+    `std::initializer_list`. Furthermore, C-style arrays can be used with
+    `std::begin()`/`std::end()`. User-defined containers can be used as long
+    as they implement random-access iterators and a contiguous storage.
 
-        @throw parse_error.108 if a tilde (`~`) in the given JSON pointer @a s
-        is not followed by `0` (representing `~`) or `1` (representing `/`);
-        see example below
+    @pre The iterator range is contiguous. Violating this precondition yields
+    undefined behavior. **This precondition is enforced with an assertion.**
+    @pre Each element in the range has a size of 1 byte. Violating this
+    precondition yields undefined behavior. **This precondition is enforced
+    with a static assertion.**
 
-        @liveexample{The example shows the construction several valid JSON
-        pointers as well as the exceptional behavior.,json_pointer}
+    @warning There is no way to enforce all preconditions at compile-time. If
+             the function is called with noncompliant iterators and with
+             assertions switched off, the behavior is undefined and will most
+             likely yield segmentation violation.
 
-        @since version 2.0.0
-        */
-        explicit json_pointer(const std::string& s = "")
-            : reference_tokens(split(s))
-        {}
+    @tparam IteratorType iterator of container with contiguous storage
+    @param[in] first  begin of the range to parse (included)
+    @param[in] last  end of the range to parse (excluded)
+    @param[in] cb  a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+    @param[in] allow_exceptions  whether to throw exceptions in case of a
+    parse error (optional, true by default)
 
-        /*!
-        @brief return a string representation of the JSON pointer
+    @return result of the deserialization
 
-        @invariant For each JSON pointer `ptr`, it holds:
-        @code {.cpp}
-        ptr == json_pointer(ptr.to_string());
-        @endcode
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
 
-        @return a string representation of the JSON pointer
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb has a super-linear complexity.
 
-        @liveexample{The example shows the result of `to_string`.,
-        json_pointer__to_string}
+    @note A UTF-8 byte order mark is silently ignored.
 
-        @since version 2.0.0
-        */
-        std::string to_string() const noexcept
-        {
-            return std::accumulate(reference_tokens.begin(),
-                                   reference_tokens.end(), std::string{},
-                                   [](const std::string & a, const std::string & b)
-            {
-                return a + "/" + escape(b);
-            });
-        }
+    @liveexample{The example below demonstrates the `parse()` function reading
+    from an iterator range.,parse__iteratortype__parser_callback_t}
 
-        /// @copydoc to_string()
-        operator std::string() const
-        {
-            return to_string();
-        }
+    @since version 2.0.3
+    */
+    template<class IteratorType, typename std::enable_if<
+                 std::is_base_of<
+                     std::random_access_iterator_tag,
+                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
+    static basic_json parse(IteratorType first, IteratorType last,
+                            const parser_callback_t cb = nullptr,
+                            const bool allow_exceptions = true)
+    {
+        basic_json result;
+        parser(detail::input_adapter(first, last), cb, allow_exceptions).parse(true, result);
+        return result;
+    }
 
-      private:
-        /*!
-        @brief remove and return last reference pointer
-        @throw out_of_range.405 if JSON pointer has no parent
-        */
-        std::string pop_back()
-        {
-            if (is_root())
-            {
-                JSON_THROW(out_of_range::create(405, "JSON pointer has no parent"));
-            }
+    template<class IteratorType, typename std::enable_if<
+                 std::is_base_of<
+                     std::random_access_iterator_tag,
+                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
+    static bool accept(IteratorType first, IteratorType last)
+    {
+        return parser(detail::input_adapter(first, last)).accept(true);
+    }
 
-            auto last = reference_tokens.back();
-            reference_tokens.pop_back();
-            return last;
-        }
+    /*!
+    @brief deserialize from stream
+    @deprecated This stream operator is deprecated and will be removed in a
+                future version of the library. Please use
+                @ref operator>>(std::istream&, basic_json&)
+                instead; that is, replace calls like `j << i;` with `i >> j;`.
+    @since version 1.0.0; deprecated since version 3.0.0
+    */
+    JSON_DEPRECATED
+    friend std::istream& operator<<(basic_json& j, std::istream& i)
+    {
+        return operator>>(i, j);
+    }
 
-        /// return whether pointer points to the root document
-        bool is_root() const
-        {
-            return reference_tokens.empty();
-        }
+    /*!
+    @brief deserialize from stream
 
-        json_pointer top() const
-        {
-            if (is_root())
-            {
-                JSON_THROW(out_of_range::create(405, "JSON pointer has no parent"));
-            }
+    Deserializes an input stream to a JSON value.
 
-            json_pointer result = *this;
-            result.reference_tokens = {reference_tokens[0]};
-            return result;
-        }
+    @param[in,out] i  input stream to read a serialized JSON value from
+    @param[in,out] j  JSON value to write the deserialized input to
+
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
 
-        /*!
-        @brief create and return a reference to the pointed to value
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser.
 
-        @complexity Linear in the number of reference tokens.
+    @note A UTF-8 byte order mark is silently ignored.
 
-        @throw parse_error.109 if array index is not a number
-        @throw type_error.313 if value cannot be unflattened
-        */
-        reference get_and_create(reference j) const
-        {
-            pointer result = &j;
+    @liveexample{The example below shows how a JSON value is constructed by
+    reading a serialization from a stream.,operator_deserialize}
 
-            // in case no reference tokens exist, return a reference to the
-            // JSON value j which will be overwritten by a primitive value
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (result->m_type)
-                {
-                    case value_t::null:
-                    {
-                        if (reference_token == "0")
-                        {
-                            // start a new array if reference token is 0
-                            result = &result->operator[](0);
-                        }
-                        else
-                        {
-                            // start a new object otherwise
-                            result = &result->operator[](reference_token);
-                        }
-                        break;
-                    }
+    @sa parse(std::istream&, const parser_callback_t) for a variant with a
+    parser callback function to filter values while parsing
 
-                    case value_t::object:
-                    {
-                        // create an entry in the object
-                        result = &result->operator[](reference_token);
-                        break;
-                    }
+    @since version 1.0.0
+    */
+    friend std::istream& operator>>(std::istream& i, basic_json& j)
+    {
+        parser(detail::input_adapter(i)).parse(false, j);
+        return i;
+    }
 
-                    case value_t::array:
-                    {
-                        // create an entry in the array
-                        JSON_TRY
-                        {
-                            result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                        }
-                        JSON_CATCH (std::invalid_argument&)
-                        {
-                            JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                        }
-                        break;
-                    }
+    /// @}
 
-                    /*
-                    The following code is only reached if there exists a
-                    reference token _and_ the current value is primitive. In
-                    this case, we have an error situation, because primitive
-                    values may only occur as single value; that is, with an
-                    empty list of reference tokens.
-                    */
-                    default:
-                    {
-                        JSON_THROW(type_error::create(313, "invalid value to unflatten"));
-                    }
-                }
-            }
+    ///////////////////////////
+    // convenience functions //
+    ///////////////////////////
 
-            return *result;
-        }
+    /*!
+    @brief return the type as string
+
+    Returns the type name as string to be used in error messages - usually to
+    indicate that a function was called on a wrong JSON type.
 
-        /*!
-        @brief return a reference to the pointed to value
+    @return a string representation of a the @a m_type member:
+            Value type  | return value
+            ----------- | -------------
+            null        | `"null"`
+            boolean     | `"boolean"`
+            string      | `"string"`
+            number      | `"number"` (for all number types)
+            object      | `"object"`
+            array       | `"array"`
+            discarded   | `"discarded"`
 
-        @note This version does not throw if a value is not present, but tries
-        to create nested values instead. For instance, calling this function
-        with pointer `"/this/that"` on a null value is equivalent to calling
-        `operator[]("this").operator[]("that")` on that value, effectively
-        changing the null value to an object.
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
 
-        @param[in] ptr  a JSON value
+    @complexity Constant.
 
-        @return reference to the JSON value pointed to by the JSON pointer
+    @liveexample{The following code exemplifies `type_name()` for all JSON
+    types.,type_name}
 
-        @complexity Linear in the length of the JSON pointer.
+    @sa @ref type() -- return the type of the JSON value
+    @sa @ref operator value_t() -- return the type of the JSON value (implicit)
 
-        @throw parse_error.106   if an array index begins with '0'
-        @throw parse_error.109   if an array index was not a number
-        @throw out_of_range.404  if the JSON pointer can not be resolved
-        */
-        reference get_unchecked(pointer ptr) const
+    @since version 1.0.0, public since 2.1.0, `const char*` and `noexcept`
+    since 3.0.0
+    */
+    const char* type_name() const noexcept
+    {
         {
-            for (const auto& reference_token : reference_tokens)
+            switch (m_type)
             {
-                // convert null values to arrays or objects before continuing
-                if (ptr->m_type == value_t::null)
-                {
-                    // check if reference token is a number
-                    const bool nums = std::all_of(reference_token.begin(),
-                                                  reference_token.end(),
-                                                  [](const char x)
-                    {
-                        return (x >= '0' and x <= '9');
-                    });
+                case value_t::null:
+                    return "null";
+                case value_t::object:
+                    return "object";
+                case value_t::array:
+                    return "array";
+                case value_t::string:
+                    return "string";
+                case value_t::boolean:
+                    return "boolean";
+                case value_t::discarded:
+                    return "discarded";
+                default:
+                    return "number";
+            }
+        }
+    }
 
-                    // change value to array for numbers or "-" or to object
-                    // otherwise
-                    if (nums or reference_token == "-")
-                    {
-                        *ptr = value_t::array;
-                    }
-                    else
-                    {
-                        *ptr = value_t::object;
-                    }
-                }
 
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // use unchecked object access
-                        ptr = &ptr->operator[](reference_token);
-                        break;
-                    }
+  private:
+    //////////////////////
+    // member variables //
+    //////////////////////
 
-                    case value_t::array:
-                    {
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'"));
-                        }
+    /// the type of the current element
+    value_t m_type = value_t::null;
 
-                        if (reference_token == "-")
-                        {
-                            // explicitly treat "-" as index beyond the end
-                            ptr = &ptr->operator[](ptr->m_value.array->size());
-                        }
-                        else
-                        {
-                            // convert array index to number; unchecked access
-                            JSON_TRY
-                            {
-                                ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                            }
-                            JSON_CATCH (std::invalid_argument&)
-                            {
-                                JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                            }
-                        }
-                        break;
-                    }
+    /// the value of the current element
+    json_value m_value = {};
+
+    //////////////////////////////////////////
+    // binary serialization/deserialization //
+    //////////////////////////////////////////
+
+    /// @name binary serialization/deserialization support
+    /// @{
+
+  public:
+    /*!
+    @brief create a CBOR serialization of a given JSON value
+
+    Serializes a given JSON value @a j to a byte vector using the CBOR (Concise
+    Binary Object Representation) serialization format. CBOR is a binary
+    serialization format which aims to be more compact than JSON itself, yet
+    more efficient to parse.
 
-                    default:
-                    {
-                        JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
-                    }
-                }
-            }
+    The library uses the following mapping from JSON values types to
+    CBOR types according to the CBOR specification (RFC 7049):
 
-            return *ptr;
-        }
+    JSON value type | value/range                                | CBOR type                          | first byte
+    --------------- | ------------------------------------------ | ---------------------------------- | ---------------
+    null            | `null`                                     | Null                               | 0xF6
+    boolean         | `true`                                     | True                               | 0xF5
+    boolean         | `false`                                    | False                              | 0xF4
+    number_integer  | -9223372036854775808..-2147483649          | Negative integer (8 bytes follow)  | 0x3B
+    number_integer  | -2147483648..-32769                        | Negative integer (4 bytes follow)  | 0x3A
+    number_integer  | -32768..-129                               | Negative integer (2 bytes follow)  | 0x39
+    number_integer  | -128..-25                                  | Negative integer (1 byte follow)   | 0x38
+    number_integer  | -24..-1                                    | Negative integer                   | 0x20..0x37
+    number_integer  | 0..23                                      | Integer                            | 0x00..0x17
+    number_integer  | 24..255                                    | Unsigned integer (1 byte follow)   | 0x18
+    number_integer  | 256..65535                                 | Unsigned integer (2 bytes follow)  | 0x19
+    number_integer  | 65536..4294967295                          | Unsigned integer (4 bytes follow)  | 0x1A
+    number_integer  | 4294967296..18446744073709551615           | Unsigned integer (8 bytes follow)  | 0x1B
+    number_unsigned | 0..23                                      | Integer                            | 0x00..0x17
+    number_unsigned | 24..255                                    | Unsigned integer (1 byte follow)   | 0x18
+    number_unsigned | 256..65535                                 | Unsigned integer (2 bytes follow)  | 0x19
+    number_unsigned | 65536..4294967295                          | Unsigned integer (4 bytes follow)  | 0x1A
+    number_unsigned | 4294967296..18446744073709551615           | Unsigned integer (8 bytes follow)  | 0x1B
+    number_float    | *any value*                                | Double-Precision Float             | 0xFB
+    string          | *length*: 0..23                            | UTF-8 string                       | 0x60..0x77
+    string          | *length*: 23..255                          | UTF-8 string (1 byte follow)       | 0x78
+    string          | *length*: 256..65535                       | UTF-8 string (2 bytes follow)      | 0x79
+    string          | *length*: 65536..4294967295                | UTF-8 string (4 bytes follow)      | 0x7A
+    string          | *length*: 4294967296..18446744073709551615 | UTF-8 string (8 bytes follow)      | 0x7B
+    array           | *size*: 0..23                              | array                              | 0x80..0x97
+    array           | *size*: 23..255                            | array (1 byte follow)              | 0x98
+    array           | *size*: 256..65535                         | array (2 bytes follow)             | 0x99
+    array           | *size*: 65536..4294967295                  | array (4 bytes follow)             | 0x9A
+    array           | *size*: 4294967296..18446744073709551615   | array (8 bytes follow)             | 0x9B
+    object          | *size*: 0..23                              | map                                | 0xA0..0xB7
+    object          | *size*: 23..255                            | map (1 byte follow)                | 0xB8
+    object          | *size*: 256..65535                         | map (2 bytes follow)               | 0xB9
+    object          | *size*: 65536..4294967295                  | map (4 bytes follow)               | 0xBA
+    object          | *size*: 4294967296..18446744073709551615   | map (8 bytes follow)               | 0xBB
 
-        /*!
-        @throw parse_error.106   if an array index begins with '0'
-        @throw parse_error.109   if an array index was not a number
-        @throw out_of_range.402  if the array index '-' is used
-        @throw out_of_range.404  if the JSON pointer can not be resolved
-        */
-        reference get_checked(pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // note: at performs range check
-                        ptr = &ptr->at(reference_token);
-                        break;
-                    }
+    @note The mapping is **complete** in the sense that any JSON value type
+          can be converted to a CBOR value.
 
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" always fails the range check
-                            JSON_THROW(out_of_range::create(402, "array index '-' (" +
-                                                            std::to_string(ptr->m_value.array->size()) +
-                                                            ") is out of range"));
-                        }
+    @note If NaN or Infinity are stored inside a JSON number, they are
+          serialized properly. This behavior differs from the @ref dump()
+          function which serializes NaN or Infinity to `null`.
 
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'"));
-                        }
+    @note The following CBOR types are not used in the conversion:
+          - byte strings (0x40..0x5F)
+          - UTF-8 strings terminated by "break" (0x7F)
+          - arrays terminated by "break" (0x9F)
+          - maps terminated by "break" (0xBF)
+          - date/time (0xC0..0xC1)
+          - bignum (0xC2..0xC3)
+          - decimal fraction (0xC4)
+          - bigfloat (0xC5)
+          - tagged items (0xC6..0xD4, 0xD8..0xDB)
+          - expected conversions (0xD5..0xD7)
+          - simple values (0xE0..0xF3, 0xF8)
+          - undefined (0xF7)
+          - half and single-precision floats (0xF9-0xFA)
+          - break (0xFF)
 
-                        // note: at performs range check
-                        JSON_TRY
-                        {
-                            ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
-                        }
-                        JSON_CATCH (std::invalid_argument&)
-                        {
-                            JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                        }
-                        break;
-                    }
+    @param[in] j  JSON value to serialize
+    @return MessagePack serialization as byte vector
 
-                    default:
-                    {
-                        JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
-                    }
-                }
-            }
+    @complexity Linear in the size of the JSON value @a j.
 
-            return *ptr;
-        }
+    @liveexample{The example shows the serialization of a JSON value to a byte
+    vector in CBOR format.,to_cbor}
 
-        /*!
-        @brief return a const reference to the pointed to value
+    @sa http://cbor.io
+    @sa @ref from_cbor(const std::vector<uint8_t>&, const size_t) for the
+        analogous deserialization
+    @sa @ref to_msgpack(const basic_json&) for the related MessagePack format
 
-        @param[in] ptr  a JSON value
+    @since version 2.0.9
+    */
+    static std::vector<uint8_t> to_cbor(const basic_json& j)
+    {
+        std::vector<uint8_t> result;
+        to_cbor(j, result);
+        return result;
+    }
 
-        @return const reference to the JSON value pointed to by the JSON
-                pointer
+    static void to_cbor(const basic_json& j, detail::output_adapter<uint8_t> o)
+    {
+        binary_writer<uint8_t>(o).write_cbor(j);
+    }
 
-        @throw parse_error.106   if an array index begins with '0'
-        @throw parse_error.109   if an array index was not a number
-        @throw out_of_range.402  if the array index '-' is used
-        @throw out_of_range.404  if the JSON pointer can not be resolved
-        */
-        const_reference get_unchecked(const_pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // use unchecked object access
-                        ptr = &ptr->operator[](reference_token);
-                        break;
-                    }
+    static void to_cbor(const basic_json& j, detail::output_adapter<char> o)
+    {
+        binary_writer<char>(o).write_cbor(j);
+    }
 
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" cannot be used for const access
-                            JSON_THROW(out_of_range::create(402, "array index '-' (" +
-                                                            std::to_string(ptr->m_value.array->size()) +
-                                                            ") is out of range"));
-                        }
+    /*!
+    @brief create a MessagePack serialization of a given JSON value
 
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'"));
-                        }
+    Serializes a given JSON value @a j to a byte vector using the MessagePack
+    serialization format. MessagePack is a binary serialization format which
+    aims to be more compact than JSON itself, yet more efficient to parse.
 
-                        // use unchecked array access
-                        JSON_TRY
-                        {
-                            ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
-                        }
-                        JSON_CATCH (std::invalid_argument&)
-                        {
-                            JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                        }
-                        break;
-                    }
+    The library uses the following mapping from JSON values types to
+    MessagePack types according to the MessagePack specification:
 
-                    default:
-                    {
-                        JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
-                    }
-                }
-            }
+    JSON value type | value/range                       | MessagePack type | first byte
+    --------------- | --------------------------------- | ---------------- | ----------
+    null            | `null`                            | nil              | 0xC0
+    boolean         | `true`                            | true             | 0xC3
+    boolean         | `false`                           | false            | 0xC2
+    number_integer  | -9223372036854775808..-2147483649 | int64            | 0xD3
+    number_integer  | -2147483648..-32769               | int32            | 0xD2
+    number_integer  | -32768..-129                      | int16            | 0xD1
+    number_integer  | -128..-33                         | int8             | 0xD0
+    number_integer  | -32..-1                           | negative fixint  | 0xE0..0xFF
+    number_integer  | 0..127                            | positive fixint  | 0x00..0x7F
+    number_integer  | 128..255                          | uint 8           | 0xCC
+    number_integer  | 256..65535                        | uint 16          | 0xCD
+    number_integer  | 65536..4294967295                 | uint 32          | 0xCE
+    number_integer  | 4294967296..18446744073709551615  | uint 64          | 0xCF
+    number_unsigned | 0..127                            | positive fixint  | 0x00..0x7F
+    number_unsigned | 128..255                          | uint 8           | 0xCC
+    number_unsigned | 256..65535                        | uint 16          | 0xCD
+    number_unsigned | 65536..4294967295                 | uint 32          | 0xCE
+    number_unsigned | 4294967296..18446744073709551615  | uint 64          | 0xCF
+    number_float    | *any value*                       | float 64         | 0xCB
+    string          | *length*: 0..31                   | fixstr           | 0xA0..0xBF
+    string          | *length*: 32..255                 | str 8            | 0xD9
+    string          | *length*: 256..65535              | str 16           | 0xDA
+    string          | *length*: 65536..4294967295       | str 32           | 0xDB
+    array           | *size*: 0..15                     | fixarray         | 0x90..0x9F
+    array           | *size*: 16..65535                 | array 16         | 0xDC
+    array           | *size*: 65536..4294967295         | array 32         | 0xDD
+    object          | *size*: 0..15                     | fix map          | 0x80..0x8F
+    object          | *size*: 16..65535                 | map 16           | 0xDE
+    object          | *size*: 65536..4294967295         | map 32           | 0xDF
 
-            return *ptr;
-        }
+    @note The mapping is **complete** in the sense that any JSON value type
+          can be converted to a MessagePack value.
 
-        /*!
-        @throw parse_error.106   if an array index begins with '0'
-        @throw parse_error.109   if an array index was not a number
-        @throw out_of_range.402  if the array index '-' is used
-        @throw out_of_range.404  if the JSON pointer can not be resolved
-        */
-        const_reference get_checked(const_pointer ptr) const
-        {
-            for (const auto& reference_token : reference_tokens)
-            {
-                switch (ptr->m_type)
-                {
-                    case value_t::object:
-                    {
-                        // note: at performs range check
-                        ptr = &ptr->at(reference_token);
-                        break;
-                    }
+    @note The following values can **not** be converted to a MessagePack value:
+          - strings with more than 4294967295 bytes
+          - arrays with more than 4294967295 elements
+          - objects with more than 4294967295 elements
 
-                    case value_t::array:
-                    {
-                        if (reference_token == "-")
-                        {
-                            // "-" always fails the range check
-                            JSON_THROW(out_of_range::create(402, "array index '-' (" +
-                                                            std::to_string(ptr->m_value.array->size()) +
-                                                            ") is out of range"));
-                        }
+    @note The following MessagePack types are not used in the conversion:
+          - bin 8 - bin 32 (0xC4..0xC6)
+          - ext 8 - ext 32 (0xC7..0xC9)
+          - float 32 (0xCA)
+          - fixext 1 - fixext 16 (0xD4..0xD8)
 
-                        // error condition (cf. RFC 6901, Sect. 4)
-                        if (reference_token.size() > 1 and reference_token[0] == '0')
-                        {
-                            JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'"));
-                        }
+    @note Any MessagePack output created @ref to_msgpack can be successfully
+          parsed by @ref from_msgpack.
 
-                        // note: at performs range check
-                        JSON_TRY
-                        {
-                            ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
-                        }
-                        JSON_CATCH (std::invalid_argument&)
-                        {
-                            JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                        }
-                        break;
-                    }
+    @note If NaN or Infinity are stored inside a JSON number, they are
+          serialized properly. This behavior differs from the @ref dump()
+          function which serializes NaN or Infinity to `null`.
 
-                    default:
-                    {
-                        JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
-                    }
-                }
-            }
+    @param[in] j  JSON value to serialize
+    @return MessagePack serialization as byte vector
 
-            return *ptr;
-        }
+    @complexity Linear in the size of the JSON value @a j.
 
-        /*!
-        @brief split the string input to reference tokens
+    @liveexample{The example shows the serialization of a JSON value to a byte
+    vector in MessagePack format.,to_msgpack}
 
-        @note This function is only called by the json_pointer constructor.
-              All exceptions below are documented there.
+    @sa http://msgpack.org
+    @sa @ref from_msgpack(const std::vector<uint8_t>&, const size_t) for the
+        analogous deserialization
+    @sa @ref to_cbor(const basic_json& for the related CBOR format
 
-        @throw parse_error.107  if the pointer is not empty or begins with '/'
-        @throw parse_error.108  if character '~' is not followed by '0' or '1'
-        */
-        static std::vector<std::string> split(const std::string& reference_string)
-        {
-            std::vector<std::string> result;
+    @since version 2.0.9
+    */
+    static std::vector<uint8_t> to_msgpack(const basic_json& j)
+    {
+        std::vector<uint8_t> result;
+        to_msgpack(j, result);
+        return result;
+    }
 
-            // special case: empty reference string -> no reference tokens
-            if (reference_string.empty())
-            {
-                return result;
-            }
+    static void to_msgpack(const basic_json& j, detail::output_adapter<uint8_t> o)
+    {
+        binary_writer<uint8_t>(o).write_msgpack(j);
+    }
 
-            // check if nonempty reference string begins with slash
-            if (reference_string[0] != '/')
-            {
-                JSON_THROW(parse_error::create(107, 1, "JSON pointer must be empty or begin with '/' - was: '" + reference_string + "'"));
-            }
+    static void to_msgpack(const basic_json& j, detail::output_adapter<char> o)
+    {
+        binary_writer<char>(o).write_msgpack(j);
+    }
 
-            // extract the reference tokens:
-            // - slash: position of the last read slash (or end of string)
-            // - start: position after the previous slash
-            for (
-                // search for the first slash after the first character
-                size_t slash = reference_string.find_first_of('/', 1),
-                // set the beginning of the first reference token
-                start = 1;
-                // we can stop if start == string::npos+1 = 0
-                start != 0;
-                // set the beginning of the next reference token
-                // (will eventually be 0 if slash == std::string::npos)
-                start = slash + 1,
-                // find next slash
-                slash = reference_string.find_first_of('/', start))
-            {
-                // use the text between the beginning of the reference token
-                // (start) and the last slash (slash).
-                auto reference_token = reference_string.substr(start, slash - start);
+    /*!
+    @brief create a JSON value from an input in CBOR format
 
-                // check reference tokens are properly escaped
-                for (size_t pos = reference_token.find_first_of('~');
-                        pos != std::string::npos;
-                        pos = reference_token.find_first_of('~', pos + 1))
-                {
-                    assert(reference_token[pos] == '~');
+    Deserializes a given input @a i to a JSON value using the CBOR (Concise
+    Binary Object Representation) serialization format.
 
-                    // ~ must be followed by 0 or 1
-                    if (pos == reference_token.size() - 1 or
-                            (reference_token[pos + 1] != '0' and
-                             reference_token[pos + 1] != '1'))
-                    {
-                        JSON_THROW(parse_error::create(108, 0, "escape character '~' must be followed with '0' or '1'"));
-                    }
-                }
+    The library maps CBOR types to JSON value types as follows:
 
-                // finally, store the reference token
-                unescape(reference_token);
-                result.push_back(reference_token);
-            }
+    CBOR type              | JSON value type | first byte
+    ---------------------- | --------------- | ----------
+    Integer                | number_unsigned | 0x00..0x17
+    Unsigned integer       | number_unsigned | 0x18
+    Unsigned integer       | number_unsigned | 0x19
+    Unsigned integer       | number_unsigned | 0x1A
+    Unsigned integer       | number_unsigned | 0x1B
+    Negative integer       | number_integer  | 0x20..0x37
+    Negative integer       | number_integer  | 0x38
+    Negative integer       | number_integer  | 0x39
+    Negative integer       | number_integer  | 0x3A
+    Negative integer       | number_integer  | 0x3B
+    Negative integer       | number_integer  | 0x40..0x57
+    UTF-8 string           | string          | 0x60..0x77
+    UTF-8 string           | string          | 0x78
+    UTF-8 string           | string          | 0x79
+    UTF-8 string           | string          | 0x7A
+    UTF-8 string           | string          | 0x7B
+    UTF-8 string           | string          | 0x7F
+    array                  | array           | 0x80..0x97
+    array                  | array           | 0x98
+    array                  | array           | 0x99
+    array                  | array           | 0x9A
+    array                  | array           | 0x9B
+    array                  | array           | 0x9F
+    map                    | object          | 0xA0..0xB7
+    map                    | object          | 0xB8
+    map                    | object          | 0xB9
+    map                    | object          | 0xBA
+    map                    | object          | 0xBB
+    map                    | object          | 0xBF
+    False                  | `false`         | 0xF4
+    True                   | `true`          | 0xF5
+    Nill                   | `null`          | 0xF6
+    Half-Precision Float   | number_float    | 0xF9
+    Single-Precision Float | number_float    | 0xFA
+    Double-Precision Float | number_float    | 0xFB
 
-            return result;
-        }
+    @warning The mapping is **incomplete** in the sense that not all CBOR
+             types can be converted to a JSON value. The following CBOR types
+             are not supported and will yield parse errors (parse_error.112):
+             - byte strings (0x40..0x5F)
+             - date/time (0xC0..0xC1)
+             - bignum (0xC2..0xC3)
+             - decimal fraction (0xC4)
+             - bigfloat (0xC5)
+             - tagged items (0xC6..0xD4, 0xD8..0xDB)
+             - expected conversions (0xD5..0xD7)
+             - simple values (0xE0..0xF3, 0xF8)
+             - undefined (0xF7)
 
-        /*!
-        @brief replace all occurrences of a substring by another string
+    @warning CBOR allows map keys of any type, whereas JSON only allows
+             strings as keys in object values. Therefore, CBOR maps with keys
+             other than UTF-8 strings are rejected (parse_error.113).
 
-        @param[in,out] s  the string to manipulate; changed so that all
-                          occurrences of @a f are replaced with @a t
-        @param[in]     f  the substring to replace with @a t
-        @param[in]     t  the string to replace @a f
+    @note Any CBOR output created @ref to_cbor can be successfully parsed by
+          @ref from_cbor.
 
-        @pre The search string @a f must not be empty. **This precondition is
-             enforced with an assertion.**
+    @param[in] i  an input in CBOR format convertible to an input adapter
+    @param[in] strict  whether to expect the input to be consumed until EOF
+                       (true by default)
+    @return deserialized JSON value
 
-        @since version 2.0.0
-        */
-        static void replace_substring(std::string& s,
-                                      const std::string& f,
-                                      const std::string& t)
-        {
-            assert(not f.empty());
+    @throw parse_error.110 if the given input ends prematurely or the end of
+    file was not reached when @a strict was set to true
+    @throw parse_error.112 if unsupported features from CBOR were
+    used in the given input @a v or if the input is not valid CBOR
+    @throw parse_error.113 if a string was expected as map key, but not found
 
-            for (
-                size_t pos = s.find(f);         // find first occurrence of f
-                pos != std::string::npos;       // make sure f was found
-                s.replace(pos, f.size(), t),    // replace with t
-                pos = s.find(f, pos + t.size()) // find next occurrence of f
-            );
-        }
+    @complexity Linear in the size of the input @a i.
 
-        /// escape tilde and slash
-        static std::string escape(std::string s)
-        {
-            // escape "~"" to "~0" and "/" to "~1"
-            replace_substring(s, "~", "~0");
-            replace_substring(s, "/", "~1");
-            return s;
-        }
+    @liveexample{The example shows the deserialization of a byte vector in CBOR
+    format to a JSON value.,from_cbor}
 
-        /// unescape tilde and slash
-        static void unescape(std::string& s)
-        {
-            // first transform any occurrence of the sequence '~1' to '/'
-            replace_substring(s, "~1", "/");
-            // then transform any occurrence of the sequence '~0' to '~'
-            replace_substring(s, "~0", "~");
-        }
+    @sa http://cbor.io
+    @sa @ref to_cbor(const basic_json&) for the analogous serialization
+    @sa @ref from_msgpack(detail::input_adapter, const bool) for the
+        related MessagePack format
 
-        /*!
-        @param[in] reference_string  the reference string to the current value
-        @param[in] value             the value to consider
-        @param[in,out] result        the result object to insert values to
+    @since version 2.0.9; parameter @a start_index since 2.1.1; changed to
+           consume input adapters, removed start_index parameter, and added
+           @a strict parameter since 3.0.0
+    */
+    static basic_json from_cbor(detail::input_adapter i,
+                                const bool strict = true)
+    {
+        return binary_reader(i).parse_cbor(strict);
+    }
 
-        @note Empty objects or arrays are flattened to `null`.
-        */
-        static void flatten(const std::string& reference_string,
-                            const basic_json& value,
-                            basic_json& result)
-        {
-            switch (value.m_type)
-            {
-                case value_t::array:
-                {
-                    if (value.m_value.array->empty())
-                    {
-                        // flatten empty array as null
-                        result[reference_string] = nullptr;
-                    }
-                    else
-                    {
-                        // iterate array and use index as reference string
-                        for (size_t i = 0; i < value.m_value.array->size(); ++i)
-                        {
-                            flatten(reference_string + "/" + std::to_string(i),
-                                    value.m_value.array->operator[](i), result);
-                        }
-                    }
-                    break;
-                }
+    /*!
+    @copydoc from_cbor(detail::input_adapter, const bool)
+    */
+    template<typename A1, typename A2,
+             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
+    static basic_json from_cbor(A1 && a1, A2 && a2, const bool strict = true)
+    {
+        return binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).parse_cbor(strict);
+    }
 
-                case value_t::object:
-                {
-                    if (value.m_value.object->empty())
-                    {
-                        // flatten empty object as null
-                        result[reference_string] = nullptr;
-                    }
-                    else
-                    {
-                        // iterate object and use keys as reference string
-                        for (const auto& element : *value.m_value.object)
-                        {
-                            flatten(reference_string + "/" + escape(element.first),
-                                    element.second, result);
-                        }
-                    }
-                    break;
-                }
+    /*!
+    @brief create a JSON value from an input in MessagePack format
 
-                default:
-                {
-                    // add primitive value with its reference string
-                    result[reference_string] = value;
-                    break;
-                }
-            }
-        }
+    Deserializes a given input @a i to a JSON value using the MessagePack
+    serialization format.
 
-        /*!
-        @param[in] value  flattened JSON
+    The library maps MessagePack types to JSON value types as follows:
 
-        @return unflattened JSON
+    MessagePack type | JSON value type | first byte
+    ---------------- | --------------- | ----------
+    positive fixint  | number_unsigned | 0x00..0x7F
+    fixmap           | object          | 0x80..0x8F
+    fixarray         | array           | 0x90..0x9F
+    fixstr           | string          | 0xA0..0xBF
+    nil              | `null`          | 0xC0
+    false            | `false`         | 0xC2
+    true             | `true`          | 0xC3
+    float 32         | number_float    | 0xCA
+    float 64         | number_float    | 0xCB
+    uint 8           | number_unsigned | 0xCC
+    uint 16          | number_unsigned | 0xCD
+    uint 32          | number_unsigned | 0xCE
+    uint 64          | number_unsigned | 0xCF
+    int 8            | number_integer  | 0xD0
+    int 16           | number_integer  | 0xD1
+    int 32           | number_integer  | 0xD2
+    int 64           | number_integer  | 0xD3
+    str 8            | string          | 0xD9
+    str 16           | string          | 0xDA
+    str 32           | string          | 0xDB
+    array 16         | array           | 0xDC
+    array 32         | array           | 0xDD
+    map 16           | object          | 0xDE
+    map 32           | object          | 0xDF
+    negative fixint  | number_integer  | 0xE0-0xFF
 
-        @throw parse_error.109 if array index is not a number
-        @throw type_error.314  if value is not an object
-        @throw type_error.315  if object values are not primitive
-        @throw type_error.313  if value cannot be unflattened
-        */
-        static basic_json unflatten(const basic_json& value)
-        {
-            if (not value.is_object())
-            {
-                JSON_THROW(type_error::create(314, "only objects can be unflattened"));
-            }
+    @warning The mapping is **incomplete** in the sense that not all
+             MessagePack types can be converted to a JSON value. The following
+             MessagePack types are not supported and will yield parse errors:
+              - bin 8 - bin 32 (0xC4..0xC6)
+              - ext 8 - ext 32 (0xC7..0xC9)
+              - fixext 1 - fixext 16 (0xD4..0xD8)
 
-            basic_json result;
+    @note Any MessagePack output created @ref to_msgpack can be successfully
+          parsed by @ref from_msgpack.
 
-            // iterate the JSON object values
-            for (const auto& element : *value.m_value.object)
-            {
-                if (not element.second.is_primitive())
-                {
-                    JSON_THROW(type_error::create(315, "values in object must be primitive"));
-                }
+    @param[in] i  an input in MessagePack format convertible to an input
+                  adapter
+    @param[in] strict  whether to expect the input to be consumed until EOF
+                       (true by default)
 
-                // assign value to reference pointed to by JSON pointer; Note
-                // that if the JSON pointer is "" (i.e., points to the whole
-                // value), function get_and_create returns a reference to
-                // result itself. An assignment will then create a primitive
-                // value.
-                json_pointer(element.first).get_and_create(result) = element.second;
-            }
+    @throw parse_error.110 if the given input ends prematurely or the end of
+    file was not reached when @a strict was set to true
+    @throw parse_error.112 if unsupported features from MessagePack were
+    used in the given input @a i or if the input is not valid MessagePack
+    @throw parse_error.113 if a string was expected as map key, but not found
 
-            return result;
-        }
+    @complexity Linear in the size of the input @a i.
 
-        friend bool operator==(json_pointer const& lhs,
-                               json_pointer const& rhs) noexcept
-        {
-            return lhs.reference_tokens == rhs.reference_tokens;
-        }
+    @liveexample{The example shows the deserialization of a byte vector in
+    MessagePack format to a JSON value.,from_msgpack}
 
-        friend bool operator!=(json_pointer const& lhs,
-                               json_pointer const& rhs) noexcept
-        {
-            return !(lhs == rhs);
-        }
+    @sa http://msgpack.org
+    @sa @ref to_msgpack(const basic_json&) for the analogous serialization
+    @sa @ref from_cbor(detail::input_adapter, const bool) for the related CBOR
+        format
 
-        /// the reference tokens
-        std::vector<std::string> reference_tokens {};
-    };
+    @since version 2.0.9; parameter @a start_index since 2.1.1; changed to
+           consume input adapters, removed start_index parameter, and added
+           @a strict parameter since 3.0.0
+    */
+    static basic_json from_msgpack(detail::input_adapter i,
+                                   const bool strict = true)
+    {
+        return binary_reader(i).parse_msgpack(strict);
+    }
+
+    /*!
+    @copydoc from_msgpack(detail::input_adapter, const bool)
+    */
+    template<typename A1, typename A2,
+             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
+    static basic_json from_msgpack(A1 && a1, A2 && a2, const bool strict = true)
+    {
+        return binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).parse_msgpack(strict);
+    }
+
+    /// @}
 
     //////////////////////////
     // JSON Pointer support //
@@ -13302,6 +13741,9 @@ basic_json_parser_74:
     pointer @a ptr. As `at` provides checked access (and no elements are
     implicitly inserted), the index '-' is always invalid. See example below.
 
+    @throw out_of_range.403 if the JSON pointer describes a key of an object
+    which cannot be found. See example below.
+
     @throw out_of_range.404 if the JSON pointer @a ptr can not be resolved.
     See example below.
 
@@ -13342,6 +13784,9 @@ basic_json_parser_74:
     pointer @a ptr. As `at` provides checked access (and no elements are
     implicitly inserted), the index '-' is always invalid. See example below.
 
+    @throw out_of_range.403 if the JSON pointer describes a key of an object
+    which cannot be found. See example below.
+
     @throw out_of_range.404 if the JSON pointer @a ptr can not be resolved.
     See example below.
 
@@ -13409,7 +13854,7 @@ basic_json_parser_74:
     @complexity Linear in the size the JSON value.
 
     @throw type_error.314  if value is not an object
-    @throw type_error.315  if object values are not primitve
+    @throw type_error.315  if object values are not primitive
 
     @liveexample{The following code shows how a flattened JSON object is
     unflattened into the original nested JSON object.,unflatten}
@@ -13557,8 +14002,8 @@ basic_json_parser_74:
                         }
                         else
                         {
-                            const auto idx = std::stoi(last_path);
-                            if (static_cast<size_type>(idx) > parent.size())
+                            const auto idx = json_pointer::array_index(last_path);
+                            if (JSON_UNLIKELY(static_cast<size_type>(idx) > parent.size()))
                             {
                                 // avoid undefined behavior
                                 JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
@@ -13593,7 +14038,7 @@ basic_json_parser_74:
             {
                 // perform range check
                 auto it = parent.find(last_path);
-                if (it != parent.end())
+                if (JSON_LIKELY(it != parent.end()))
                 {
                     parent.erase(it);
                 }
@@ -13605,12 +14050,12 @@ basic_json_parser_74:
             else if (parent.is_array())
             {
                 // note erase performs range check
-                parent.erase(static_cast<size_type>(std::stoi(last_path)));
+                parent.erase(static_cast<size_type>(json_pointer::array_index(last_path)));
             }
         };
 
         // type check: top level value must be an array
-        if (not json_patch.is_array())
+        if (JSON_UNLIKELY(not json_patch.is_array()))
         {
             JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects"));
         }
@@ -13630,13 +14075,13 @@ basic_json_parser_74:
                 const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";
 
                 // check if desired value is present
-                if (it == val.m_value.object->end())
+                if (JSON_UNLIKELY(it == val.m_value.object->end()))
                 {
                     JSON_THROW(parse_error::create(105, 0, error_msg + " must have member '" + member + "'"));
                 }
 
                 // check if result is of type string
-                if (string_type and not it->second.is_string())
+                if (JSON_UNLIKELY(string_type and not it->second.is_string()))
                 {
                     JSON_THROW(parse_error::create(105, 0, error_msg + " must have string member '" + member + "'"));
                 }
@@ -13646,7 +14091,7 @@ basic_json_parser_74:
             };
 
             // type check: every element of the array must be an object
-            if (not val.is_object())
+            if (JSON_UNLIKELY(not val.is_object()))
             {
                 JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects"));
             }
@@ -13696,11 +14141,16 @@ basic_json_parser_74:
 
                 case patch_operations::copy:
                 {
-                    const std::string from_path = get_value("copy", "from", true);;
+                    const std::string from_path = get_value("copy", "from", true);
                     const json_pointer from_ptr(from_path);
 
                     // the "from" location must exist - use at()
-                    result[ptr] = result.at(from_ptr);
+                    basic_json v = result.at(from_ptr);
+
+                    // The copy is functionally identical to an "add"
+                    // operation at the target location using the value
+                    // specified in the "from" member.
+                    operation_add(ptr, v);
                     break;
                 }
 
@@ -13719,7 +14169,7 @@ basic_json_parser_74:
                     }
 
                     // throw an exception if test fails
-                    if (not success)
+                    if (JSON_UNLIKELY(not success))
                     {
                         JSON_THROW(other_error::create(501, "unsuccessful: " + val.dump()));
                     }
@@ -13771,8 +14221,7 @@ basic_json_parser_74:
 
     @since version 2.0.0
     */
-    static basic_json diff(const basic_json& source,
-                           const basic_json& target,
+    static basic_json diff(const basic_json& source, const basic_json& target,
                            const std::string& path = "")
     {
         // the patch
@@ -13789,9 +14238,7 @@ basic_json_parser_74:
             // different types: replace value
             result.push_back(
             {
-                {"op", "replace"},
-                {"path", path},
-                {"value", target}
+                {"op", "replace"}, {"path", path}, {"value", target}
             });
         }
         else
@@ -13801,7 +14248,7 @@ basic_json_parser_74:
                 case value_t::array:
                 {
                     // first pass: traverse common elements
-                    size_t i = 0;
+                    std::size_t i = 0;
                     while (i < source.size() and i < target.size())
                     {
                         // recursive call to compare array values at index i
@@ -13845,7 +14292,7 @@ basic_json_parser_74:
                 case value_t::object:
                 {
                     // first pass: traverse this object's elements
-                    for (auto it = source.begin(); it != source.end(); ++it)
+                    for (auto it = source.cbegin(); it != source.cend(); ++it)
                     {
                         // escape the key name to be used in a JSON patch
                         const auto key = json_pointer::escape(it.key());
@@ -13861,14 +14308,13 @@ basic_json_parser_74:
                             // found a key that is not in o -> remove it
                             result.push_back(object(
                             {
-                                {"op", "remove"},
-                                {"path", path + "/" + key}
+                                {"op", "remove"}, {"path", path + "/" + key}
                             }));
                         }
                     }
 
                     // second pass: traverse other object's elements
-                    for (auto it = target.begin(); it != target.end(); ++it)
+                    for (auto it = target.cbegin(); it != target.cend(); ++it)
                     {
                         if (source.find(it.key()) == source.end())
                         {
@@ -13876,8 +14322,7 @@ basic_json_parser_74:
                             const auto key = json_pointer::escape(it.key());
                             result.push_back(
                             {
-                                {"op", "add"},
-                                {"path", path + "/" + key},
+                                {"op", "add"}, {"path", path + "/" + key},
                                 {"value", it.value()}
                             });
                         }
@@ -13891,9 +14336,7 @@ basic_json_parser_74:
                     // both primitive type: replace value
                     result.push_back(
                     {
-                        {"op", "replace"},
-                        {"path", path},
-                        {"value", target}
+                        {"op", "replace"}, {"path", path}, {"value", target}
                     });
                     break;
                 }
@@ -13919,6 +14362,400 @@ uses the standard template types.
 @since version 1.0.0
 */
 using json = basic_json<>;
+
+//////////////////
+// json_pointer //
+//////////////////
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+NLOHMANN_BASIC_JSON_TPL&
+json_pointer::get_and_create(NLOHMANN_BASIC_JSON_TPL& j) const
+{
+    using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type;
+    auto result = &j;
+
+    // in case no reference tokens exist, return a reference to the JSON value
+    // j which will be overwritten by a primitive value
+    for (const auto& reference_token : reference_tokens)
+    {
+        switch (result->m_type)
+        {
+            case detail::value_t::null:
+            {
+                if (reference_token == "0")
+                {
+                    // start a new array if reference token is 0
+                    result = &result->operator[](0);
+                }
+                else
+                {
+                    // start a new object otherwise
+                    result = &result->operator[](reference_token);
+                }
+                break;
+            }
+
+            case detail::value_t::object:
+            {
+                // create an entry in the object
+                result = &result->operator[](reference_token);
+                break;
+            }
+
+            case detail::value_t::array:
+            {
+                // create an entry in the array
+                JSON_TRY
+                {
+                    result = &result->operator[](static_cast<size_type>(array_index(reference_token)));
+                }
+                JSON_CATCH(std::invalid_argument&)
+                {
+                    JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                }
+                break;
+            }
+
+            /*
+            The following code is only reached if there exists a reference
+            token _and_ the current value is primitive. In this case, we have
+            an error situation, because primitive values may only occur as
+            single value; that is, with an empty list of reference tokens.
+            */
+            default:
+                JSON_THROW(detail::type_error::create(313, "invalid value to unflatten"));
+        }
+    }
+
+    return *result;
+}
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+NLOHMANN_BASIC_JSON_TPL&
+json_pointer::get_unchecked(NLOHMANN_BASIC_JSON_TPL* ptr) const
+{
+    using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type;
+    for (const auto& reference_token : reference_tokens)
+    {
+        // convert null values to arrays or objects before continuing
+        if (ptr->m_type == detail::value_t::null)
+        {
+            // check if reference token is a number
+            const bool nums =
+                std::all_of(reference_token.begin(), reference_token.end(),
+                            [](const char x)
+            {
+                return (x >= '0' and x <= '9');
+            });
+
+            // change value to array for numbers or "-" or to object otherwise
+            *ptr = (nums or reference_token == "-")
+                   ? detail::value_t::array
+                   : detail::value_t::object;
+        }
+
+        switch (ptr->m_type)
+        {
+            case detail::value_t::object:
+            {
+                // use unchecked object access
+                ptr = &ptr->operator[](reference_token);
+                break;
+            }
+
+            case detail::value_t::array:
+            {
+                // error condition (cf. RFC 6901, Sect. 4)
+                if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0'))
+                {
+                    JSON_THROW(detail::parse_error::create(106, 0,
+                                                           "array index '" + reference_token +
+                                                           "' must not begin with '0'"));
+                }
+
+                if (reference_token == "-")
+                {
+                    // explicitly treat "-" as index beyond the end
+                    ptr = &ptr->operator[](ptr->m_value.array->size());
+                }
+                else
+                {
+                    // convert array index to number; unchecked access
+                    JSON_TRY
+                    {
+                        ptr = &ptr->operator[](
+                            static_cast<size_type>(array_index(reference_token)));
+                    }
+                    JSON_CATCH(std::invalid_argument&)
+                    {
+                        JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                    }
+                }
+                break;
+            }
+
+            default:
+                JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
+        }
+    }
+
+    return *ptr;
+}
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+NLOHMANN_BASIC_JSON_TPL&
+json_pointer::get_checked(NLOHMANN_BASIC_JSON_TPL* ptr) const
+{
+    using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type;
+    for (const auto& reference_token : reference_tokens)
+    {
+        switch (ptr->m_type)
+        {
+            case detail::value_t::object:
+            {
+                // note: at performs range check
+                ptr = &ptr->at(reference_token);
+                break;
+            }
+
+            case detail::value_t::array:
+            {
+                if (JSON_UNLIKELY(reference_token == "-"))
+                {
+                    // "-" always fails the range check
+                    JSON_THROW(detail::out_of_range::create(402,
+                                                            "array index '-' (" + std::to_string(ptr->m_value.array->size()) +
+                                                            ") is out of range"));
+                }
+
+                // error condition (cf. RFC 6901, Sect. 4)
+                if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0'))
+                {
+                    JSON_THROW(detail::parse_error::create(106, 0,
+                                                           "array index '" + reference_token +
+                                                           "' must not begin with '0'"));
+                }
+
+                // note: at performs range check
+                JSON_TRY
+                {
+                    ptr = &ptr->at(static_cast<size_type>(array_index(reference_token)));
+                }
+                JSON_CATCH(std::invalid_argument&)
+                {
+                    JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                }
+                break;
+            }
+
+            default:
+                JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
+        }
+    }
+
+    return *ptr;
+}
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+const NLOHMANN_BASIC_JSON_TPL&
+json_pointer::get_unchecked(const NLOHMANN_BASIC_JSON_TPL* ptr) const
+{
+    using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type;
+    for (const auto& reference_token : reference_tokens)
+    {
+        switch (ptr->m_type)
+        {
+            case detail::value_t::object:
+            {
+                // use unchecked object access
+                ptr = &ptr->operator[](reference_token);
+                break;
+            }
+
+            case detail::value_t::array:
+            {
+                if (JSON_UNLIKELY(reference_token == "-"))
+                {
+                    // "-" cannot be used for const access
+                    JSON_THROW(detail::out_of_range::create(402,
+                                                            "array index '-' (" + std::to_string(ptr->m_value.array->size()) +
+                                                            ") is out of range"));
+                }
+
+                // error condition (cf. RFC 6901, Sect. 4)
+                if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0'))
+                {
+                    JSON_THROW(detail::parse_error::create(106, 0,
+                                                           "array index '" + reference_token +
+                                                           "' must not begin with '0'"));
+                }
+
+                // use unchecked array access
+                JSON_TRY
+                {
+                    ptr = &ptr->operator[](
+                        static_cast<size_type>(array_index(reference_token)));
+                }
+                JSON_CATCH(std::invalid_argument&)
+                {
+                    JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                }
+                break;
+            }
+
+            default:
+                JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
+        }
+    }
+
+    return *ptr;
+}
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+const NLOHMANN_BASIC_JSON_TPL&
+json_pointer::get_checked(const NLOHMANN_BASIC_JSON_TPL* ptr) const
+{
+    using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type;
+    for (const auto& reference_token : reference_tokens)
+    {
+        switch (ptr->m_type)
+        {
+            case detail::value_t::object:
+            {
+                // note: at performs range check
+                ptr = &ptr->at(reference_token);
+                break;
+            }
+
+            case detail::value_t::array:
+            {
+                if (JSON_UNLIKELY(reference_token == "-"))
+                {
+                    // "-" always fails the range check
+                    JSON_THROW(detail::out_of_range::create(402,
+                                                            "array index '-' (" + std::to_string(ptr->m_value.array->size()) +
+                                                            ") is out of range"));
+                }
+
+                // error condition (cf. RFC 6901, Sect. 4)
+                if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0'))
+                {
+                    JSON_THROW(detail::parse_error::create(106, 0,
+                                                           "array index '" + reference_token +
+                                                           "' must not begin with '0'"));
+                }
+
+                // note: at performs range check
+                JSON_TRY
+                {
+                    ptr = &ptr->at(static_cast<size_type>(array_index(reference_token)));
+                }
+                JSON_CATCH(std::invalid_argument&)
+                {
+                    JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                }
+                break;
+            }
+
+            default:
+                JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
+        }
+    }
+
+    return *ptr;
+}
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+void json_pointer::flatten(const std::string& reference_string,
+                           const NLOHMANN_BASIC_JSON_TPL& value,
+                           NLOHMANN_BASIC_JSON_TPL& result)
+{
+    switch (value.m_type)
+    {
+        case detail::value_t::array:
+        {
+            if (value.m_value.array->empty())
+            {
+                // flatten empty array as null
+                result[reference_string] = nullptr;
+            }
+            else
+            {
+                // iterate array and use index as reference string
+                for (std::size_t i = 0; i < value.m_value.array->size(); ++i)
+                {
+                    flatten(reference_string + "/" + std::to_string(i),
+                            value.m_value.array->operator[](i), result);
+                }
+            }
+            break;
+        }
+
+        case detail::value_t::object:
+        {
+            if (value.m_value.object->empty())
+            {
+                // flatten empty object as null
+                result[reference_string] = nullptr;
+            }
+            else
+            {
+                // iterate object and use keys as reference string
+                for (const auto& element : *value.m_value.object)
+                {
+                    flatten(reference_string + "/" + escape(element.first), element.second, result);
+                }
+            }
+            break;
+        }
+
+        default:
+        {
+            // add primitive value with its reference string
+            result[reference_string] = value;
+            break;
+        }
+    }
+}
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+NLOHMANN_BASIC_JSON_TPL
+json_pointer::unflatten(const NLOHMANN_BASIC_JSON_TPL& value)
+{
+    if (JSON_UNLIKELY(not value.is_object()))
+    {
+        JSON_THROW(detail::type_error::create(314, "only objects can be unflattened"));
+    }
+
+    NLOHMANN_BASIC_JSON_TPL result;
+
+    // iterate the JSON object values
+    for (const auto& element : *value.m_value.object)
+    {
+        if (JSON_UNLIKELY(not element.second.is_primitive()))
+        {
+            JSON_THROW(detail::type_error::create(315, "values in object must be primitive"));
+        }
+
+        // assign value to reference pointed to by JSON pointer; Note that if
+        // the JSON pointer is "" (i.e., points to the whole value), function
+        // get_and_create returns a reference to result itself. An assignment
+        // will then create a primitive value.
+        json_pointer(element.first).get_and_create(result) = element.second;
+    }
+
+    return result;
+}
+
+inline bool operator==(json_pointer const& lhs, json_pointer const& rhs) noexcept
+{
+    return (lhs.reference_tokens == rhs.reference_tokens);
+}
+
+inline bool operator!=(json_pointer const& lhs, json_pointer const& rhs) noexcept
+{
+    return not (lhs == rhs);
+}
 } // namespace nlohmann
 
 
@@ -13962,8 +14799,10 @@ struct hash<nlohmann::json>
 };
 
 /// specialization for std::less<value_t>
-template <>
-struct less<::nlohmann::detail::value_t>
+/// @note: do not remove the space after '<',
+///        see https://github.com/nlohmann/json/pull/679
+template<>
+struct less< ::nlohmann::detail::value_t>
 {
     /*!
     @brief compare two value_t enum values
@@ -14026,6 +14865,10 @@ inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std
 #undef JSON_CATCH
 #undef JSON_THROW
 #undef JSON_TRY
+#undef JSON_LIKELY
+#undef JSON_UNLIKELY
 #undef JSON_DEPRECATED
+#undef NLOHMANN_BASIC_JSON_TPL_DECLARATION
+#undef NLOHMANN_BASIC_JSON_TPL
 
 #endif
diff --git a/make-linux.mk b/make-linux.mk
index 89cda781..37f1a832 100644
--- a/make-linux.mk
+++ b/make-linux.mk
@@ -73,7 +73,7 @@ else
 	CFLAGS?=-O3 -fstack-protector
 	override CFLAGS+=-Wall -Wno-deprecated -fPIE -pthread $(INCLUDES) -DNDEBUG $(DEFS)
 	CXXFLAGS?=-O3 -fstack-protector
-	override CXXFLAGS+=-Wall -Wno-deprecated -Wno-unused-result -Wreorder -fPIE -std=c++11 -pthread $(INCLUDES) -DNDEBUG $(DEFS)
+	override CXXFLAGS+=-Wall -Wno-deprecated -fPIE -std=c++11 -pthread $(INCLUDES) -DNDEBUG $(DEFS)
 	override LDFLAGS+=-pie -Wl,-z,relro,-z,now
 	STRIP?=strip
 	STRIP+=--strip-all
diff --git a/node/Hashtable.hpp b/node/Hashtable.hpp
index 58dc8fca..777e88dc 100644
--- a/node/Hashtable.hpp
+++ b/node/Hashtable.hpp
@@ -105,7 +105,7 @@ public:
 		Hashtable *_ht;
 		_Bucket *_b;
 	};
-	friend class Hashtable::Iterator;
+	//friend class Hashtable<K,V>::Iterator;
 
 	/**
 	 * @param bc Initial capacity in buckets (default: 64, must be nonzero)
diff --git a/node/Path.hpp b/node/Path.hpp
index 3d468ad9..e12328ff 100644
--- a/node/Path.hpp
+++ b/node/Path.hpp
@@ -158,7 +158,7 @@ public:
 	/**
 	 * @return Local socket as specified by external code
 	 */
-	inline const int64_t localSocket() const { return _localSocket; }
+	inline int64_t localSocket() const { return _localSocket; }
 
 	/**
 	 * @return Physical address
diff --git a/node/Utils.hpp b/node/Utils.hpp
index 1b2b65aa..a24f2c9a 100644
--- a/node/Utils.hpp
+++ b/node/Utils.hpp
@@ -41,8 +41,8 @@
 #include "Constants.hpp"
 
 #ifdef __LINUX__
-
-#if (defined(_MSC_VER) || defined(__GNUC__)) && (defined(__amd64) || defined(__amd64__) || defined(__x86_64) || defined(__x86_64__) || defined(__AMD64) || defined(__AMD64__) || defined(_M_X64))
+//#if (defined(_MSC_VER) || defined(__GNUC__)) && (defined(__amd64) || defined(__amd64__) || defined(__x86_64) || defined(__x86_64__) || defined(__AMD64) || defined(__AMD64__) || defined(_M_X64))
+#if 0
 #include <emmintrin.h>
 static inline void ZT_FAST_MEMCPY(void *a,const void *b,unsigned long k)
 {
@@ -62,8 +62,8 @@ static inline void ZT_FAST_MEMCPY(void *a,const void *b,unsigned long k)
 		k -= 64;
 	}
 	while (k >= 16) {
-		__m128 t1 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(bb));
-		_mm_storeu_si128(reinterpret_cast<__m128i *>(aa),t1);
+		__m128 t1 = _mm_loadu_ps(reinterpret_cast<const float *>(bb));
+		_mm_storeu_ps(reinterpret_cast<float *>(aa),t1);
 		bb += 16;
 		aa += 16;
 		k -= 16;
@@ -74,7 +74,6 @@ static inline void ZT_FAST_MEMCPY(void *a,const void *b,unsigned long k)
 #else
 #define ZT_FAST_MEMCPY(a,b,c) memcpy(a,b,c)
 #endif
-
 #else
 #define ZT_FAST_MEMCPY(a,b,c) memcpy(a,b,c)
 #endif
diff --git a/osdep/Phy.hpp b/osdep/Phy.hpp
index 243db0a8..e359ccdd 100644
--- a/osdep/Phy.hpp
+++ b/osdep/Phy.hpp
@@ -816,7 +816,7 @@ public:
 	 * @param sock Stream connection socket
 	 * @param notifyWritable Want writable notifications?
 	 */
-	inline const void setNotifyWritable(PhySocket *sock,bool notifyWritable)
+	inline void setNotifyWritable(PhySocket *sock,bool notifyWritable)
 	{
 		PhySocketImpl &sws = *(reinterpret_cast<PhySocketImpl *>(sock));
 		if (notifyWritable) {
@@ -836,7 +836,7 @@ public:
 	 * @param sock Socket to modify
 	 * @param notifyReadable True if socket should be monitored for readability
 	 */
-	inline const void setNotifyReadable(PhySocket *sock,bool notifyReadable)
+	inline void setNotifyReadable(PhySocket *sock,bool notifyReadable)
 	{
 		PhySocketImpl &sws = *(reinterpret_cast<PhySocketImpl *>(sock));
 		if (notifyReadable) {
-- 
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