Integrate Hashtable into Multicaster, where @mwarning found heaviest std::map() overhead.

This commit is contained in:
Adam Ierymenko 2015-08-27 16:17:21 -07:00
parent 3947807b1f
commit b11ffc9635
5 changed files with 119 additions and 59 deletions

View file

@ -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 *const b = new _Bucket(k,v);
_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 *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;