1 files changed, 200 insertions, 0 deletions
diff --git a/src/validators/numeric.ml b/src/validators/numeric.ml
new file mode 100644
index 0000000..0c75f83
--- /dev/null
+++ b/src/validators/numeric.ml
@@ -0,0 +1,200 @@
+type numeric_str = Number_string of string | Range_string of string
+type numeric_val = Number_float of float | Range_float of float * float
+
+type options = {
+  positive: bool;
+  nonnegative: bool;
+  allow_float: bool;
+  ranges: string list;
+  not_ranges: string list;
+  not_values: string list;
+  relative: bool;
+  allow_range: bool;
+  require_range: bool;
+}
+
+let default_opts = {
+  positive = false;
+  nonnegative = false;
+  allow_float = false;
+  ranges = [];
+  not_ranges = [];
+  not_values = [];
+  relative = false;
+  allow_range = false;
+  require_range = false;
+}
+
+let opts = ref default_opts
+
+let number_arg = ref ""
+
+let args = [
+    ("--non-negative", Arg.Unit (fun () -> opts := {!opts with nonnegative=true}), "Check if the number is non-negative (>= 0)");
+    ("--positive", Arg.Unit (fun () -> opts := {!opts with positive=true}), "Check if the number is positive (> 0)");
+    ("--range", Arg.String (fun s -> let optsv = !opts in opts := {optsv with ranges=(s :: optsv.ranges)}), "Check if the number or range is within a range (inclusive)");
+    ("--not-range", Arg.String (fun s -> let optsv = !opts in opts := {optsv with not_ranges=(s :: optsv.not_ranges)}), "Check if the number or range is not within a range (inclusive)");
+    ("--not-value", Arg.String (fun s -> let optsv = !opts in opts := {optsv with not_values=(s :: optsv.not_values)}), "Check if the number does not equal a specific value");
+    ("--float", Arg.Unit (fun () -> opts := {!opts with allow_float=true}), "Allow floating-point numbers");
+    ("--relative", Arg.Unit (fun () -> opts := {!opts with relative=true}), "Allow relative increment/decrement (+/-N)");
+    ("--allow-range", Arg.Unit (fun () -> opts := {!opts with allow_range=true}), "Allow the argument to be a range rather than a single number");
+    ("--require-range", Arg.Unit (fun () -> opts := {!opts with require_range=true; allow_range=true}), "Require the argument to be a range rather than a single number");
+    ("--", Arg.Rest (fun s -> number_arg := s), "Interpret next item as an argument");
+]
+let usage = Printf.sprintf "Usage: %s [OPTIONS] <number>|<range>" Sys.argv.(0)
+
+let () = if Array.length Sys.argv = 1 then (Arg.usage args usage; exit 1)
+let () = Arg.parse args (fun s -> number_arg := s) usage
+
+let check_nonnegative opts m =
+  if opts.nonnegative then
+    match m with
+    | Number_float n ->
+        if (n < 0.0) then
+          failwith "Number should be non-negative."
+    | Range_float _ ->
+        failwith "option '--non-negative' does not apply to a range value"
+
+let check_positive opts m =
+  if opts.positive then
+    match m with
+    | Number_float n ->
+        if (n <= 0.0) then
+          failwith "Number should be positive"
+    | Range_float _ ->
+        failwith "option '--positive does' not apply to a range value"
+
+let looks_like_number value =
+  try let _ = Pcre.exec ~pat:"^(\\-?)[0-9]+(\\.[0-9]+)?$" value in true
+  with Not_found -> false
+
+let is_relative value =
+  try let _ = Pcre.exec ~pat:"^[+-][0-9]+$" value in true
+  with Not_found -> false
+
+let number_string_drop_modifier value =
+  String.sub value 1 (String.length value - 1)
+
+let get_relative opts t =
+  if opts.relative then
+    match t with
+    | Number_string s ->
+        if not (is_relative s) then
+          failwith "Value is not a relative increment/decrement"
+        else Number_string (number_string_drop_modifier s)
+    | Range_string _ ->
+        failwith "increment/decrement does not apply to a range value"
+  else t
+
+let number_of_string opts s =
+  if not (looks_like_number s) then Printf.ksprintf failwith "'%s' is not a valid number" s else
+  let n = float_of_string_opt s in
+  match n with
+  | Some n ->
+    (* If floats are explicitly allowed, just return the number. *)
+    if opts.allow_float then n
+    (* If floats are not explicitly allowed, check if the argument has a decimal separator in it.
+       If the argument string contains a dot but float_of_string didn't dislike it,
+       it's a valid number but not an integer.
+     *)
+    else if not (String.contains s '.') then n
+    (* If float_of_string returned None, the argument string is just garbage rather than a number. *)
+    else Printf.ksprintf failwith "'%s' is not a valid integer number" s
+  | None ->
+     Printf.ksprintf failwith "'%s' is not a valid number" s
+
+let range_of_string opts s =
+  let rs = String.split_on_char '-' s |> List.map String.trim |> List.map (number_of_string opts) in
+  match rs with
+  | [l; r] -> (l, r)
+  | exception (Failure msg) ->
+    (* Some of the numbers in the range are bad. *)
+    Printf.ksprintf failwith "'%s' is not a valid number range: %s" s msg
+  | _ ->
+    (* The range itself if malformed, like 1-10-20. *)
+    Printf.ksprintf failwith "'%s' is not a valid number range" s
+
+let value_in_ranges ranges n =
+  let in_range (l, r) n = (n >= l) && (n <= r) in
+  List.fold_left (fun acc r -> acc || (in_range r n)) false ranges
+
+let value_not_in_ranges ranges n =
+  let in_range (l, r) n = (n >= l) && (n <= r) in
+  List.fold_left (fun acc r -> acc && (not (in_range r n))) true ranges
+
+let check_ranges opts m =
+  if opts.ranges <> [] then
+    let ranges = List.map (range_of_string opts) opts.ranges in
+    match m with
+    | Number_float n ->
+        if not (value_in_ranges ranges n) then
+          Printf.ksprintf failwith "Number is not in any of allowed ranges"
+    | Range_float (i, j) ->
+        if (not (value_in_ranges ranges i) ||
+            not (value_in_ranges ranges j)) then
+              Printf.ksprintf failwith "Range is not in any of allowed ranges"
+
+
+let check_not_ranges opts m =
+  if opts.not_ranges <> [] then
+    let ranges = List.map (range_of_string opts) opts.not_ranges in
+    match m with
+    | Number_float n ->
+        if not (value_not_in_ranges ranges n) then
+          Printf.ksprintf failwith "Number is in one of excluded ranges"
+    | Range_float (i, j) ->
+        if (not (value_not_in_ranges ranges i) ||
+            not (value_not_in_ranges ranges j)) then
+              Printf.ksprintf failwith "Range is in one of excluded ranges"
+
+let check_not_values opts m =
+  let excluded_values = List.map (number_of_string opts) opts.not_values in
+  if excluded_values = [] then () else
+  match m with
+  | Range_float _ -> Printf.ksprintf failwith "--not-value cannot be used with ranges"
+  | Number_float num ->
+    begin
+      let res = List.find_opt ((=) num) excluded_values in
+      match res with
+      | None -> ()
+      | Some _ -> Printf.ksprintf failwith "Value is excluded by --not-value"
+    end
+
+let check_argument_type opts m =
+  match m with
+  | Number_float _ ->
+    if opts.require_range then Printf.ksprintf failwith "Value must be a range, not a number"
+    else ()
+  | Range_float _ ->
+    if opts.allow_range then ()
+    else Printf.ksprintf failwith "Value must be a number, not a range"
+
+let is_range_val s =
+  try let _ = Pcre.exec ~pat:"^[0-9]+-[0-9]+$" s in true
+  with Not_found -> false
+
+let var_numeric_str s =
+  match is_range_val s with
+  | true -> Range_string s
+  | false ->  Number_string s
+
+let () = try
+  let s = var_numeric_str !number_arg in
+  let opts = !opts in
+  let s = get_relative opts s in
+  let n =
+    match s with
+    | Number_string r -> Number_float (number_of_string opts r)
+    | Range_string r -> let i, j = range_of_string opts r in
+                   Range_float (i, j)
+  in
+  check_argument_type opts n;
+  check_nonnegative opts n;
+  check_positive opts n;
+  check_not_values opts n;
+  check_ranges opts n;
+  check_not_ranges opts n
+with (Failure err) ->
+  print_endline err;
+  exit 1
+