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-rw-r--r--node/Hashtable.hpp97
1 files changed, 68 insertions, 29 deletions
diff --git a/node/Hashtable.hpp b/node/Hashtable.hpp
index bba1fa2b..c997d54f 100644
--- a/node/Hashtable.hpp
+++ b/node/Hashtable.hpp
@@ -19,7 +19,6 @@
*
* 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
- *
*/
#ifndef ZT_HASHTABLE_HPP
@@ -39,9 +38,6 @@ namespace ZeroTier {
* This is not a drop-in replacement for STL containers, and has several
* limitations. It's designed to be small and fast for use in the
* ZeroTier core.
- *
- * Pairs of values can also be used as a key. In this case the first and
- * second element of the pair's hash codes are XORed.
*/
template<typename K,typename V>
class Hashtable
@@ -49,12 +45,11 @@ class Hashtable
private:
struct _Bucket
{
- _Bucket(const K &k,const V &v) :
- k(k),
- v(v) {}
- _Bucket *next;
+ _Bucket(const K &k,const V &v) : k(k),v(v) {}
+ _Bucket(const K &k) : k(k),v() {}
K k;
V v;
+ _Bucket *next;
};
public:
@@ -188,35 +183,56 @@ public:
/**
* @param k Key
* @param v Value
+ * @return Reference to value in table
*/
- inline void set(const K &k,const V &v)
+ inline V &set(const K &k,const V &v)
{
- if (_s >= _bc) {
- const unsigned long nc = _bc * 2;
- _Bucket **nt = reinterpret_cast<_Bucket **>(::malloc(sizeof(_Bucket *) * nc));
- if (nt) {
- for(unsigned long i=0;i<nc;++i)
- nt[i] = (_Bucket *)0;
- for(unsigned long i=0;i<_bc;++i) {
- _Bucket *b = _t[i];
- while (b) {
- _Bucket *const nb = b->next;
- const unsigned long nidx = _hc(b->k) % nc;
- b->next = nt[nidx];
- nt[nidx] = b;
- b = nb;
- }
- }
- ::free(_t);
- _t = nt;
- _bc = nc;
+ const unsigned long bidx = _hc(k) % _bc;
+
+ _Bucket *b = _t[bidx];
+ while (b) {
+ if (b->k == k) {
+ b->v = v;
+ return b->v;
}
+ b = b->next;
}
+
+ if (_s >= _bc)
+ _grow();
+
+ b = new _Bucket(k,v);
+ b->next = _t[bidx];
+ _t[bidx] = b;
+ ++_s;
+
+ return b->v;
+ }
+
+ /**
+ * @param k Key
+ * @return Value, possibly newly created
+ */
+ inline V &operator[](const K &k)
+ {
const unsigned long bidx = _hc(k) % _bc;
- _Bucket *const b = new _Bucket(k,v);
+
+ _Bucket *b = _t[bidx];
+ while (b) {
+ if (b->k == k)
+ return b->v;
+ b = b->next;
+ }
+
+ if (_s >= _bc)
+ _grow();
+
+ b = new _Bucket(k);
b->next = _t[bidx];
_t[bidx] = b;
++_s;
+
+ return b->v;
}
/**
@@ -242,6 +258,29 @@ private:
return (unsigned long)((i ^ (i >> 32)) * 2654435761ULL);
}
+ inline void _grow()
+ {
+ const unsigned long nc = _bc * 2;
+ _Bucket **nt = reinterpret_cast<_Bucket **>(::malloc(sizeof(_Bucket *) * nc));
+ if (nt) {
+ for(unsigned long i=0;i<nc;++i)
+ nt[i] = (_Bucket *)0;
+ for(unsigned long i=0;i<_bc;++i) {
+ _Bucket *b = _t[i];
+ while (b) {
+ _Bucket *const nb = b->next;
+ const unsigned long nidx = _hc(b->k) % nc;
+ b->next = nt[nidx];
+ nt[nidx] = b;
+ b = nb;
+ }
+ }
+ ::free(_t);
+ _t = nt;
+ _bc = nc;
+ }
+ }
+
_Bucket **_t;
unsigned long _bc;
unsigned long _s;