mirror of
https://gitlab.winehq.org/wine/wine-gecko.git
synced 2024-09-13 09:24:08 -07:00
88 lines
2.5 KiB
C++
88 lines
2.5 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#include "CacheHashUtils.h"
|
|
|
|
#include "plstr.h"
|
|
|
|
namespace mozilla {
|
|
namespace net {
|
|
|
|
/**
|
|
* CacheHashUtils::Hash(const char * key, uint32_t initval)
|
|
*
|
|
* See http://burtleburtle.net/bob/hash/evahash.html for more information
|
|
* about this hash function.
|
|
*
|
|
* This algorithm is used to check the data integrity.
|
|
*/
|
|
|
|
static inline void hashmix(uint32_t& a, uint32_t& b, uint32_t& c)
|
|
{
|
|
a -= b; a -= c; a ^= (c>>13);
|
|
b -= c; b -= a; b ^= (a<<8);
|
|
c -= a; c -= b; c ^= (b>>13);
|
|
a -= b; a -= c; a ^= (c>>12);
|
|
b -= c; b -= a; b ^= (a<<16);
|
|
c -= a; c -= b; c ^= (b>>5);
|
|
a -= b; a -= c; a ^= (c>>3);
|
|
b -= c; b -= a; b ^= (a<<10);
|
|
c -= a; c -= b; c ^= (b>>15);
|
|
}
|
|
|
|
CacheHashUtils::Hash32_t
|
|
CacheHashUtils::Hash(const char *aData, uint32_t aSize, uint32_t aInitval)
|
|
{
|
|
const uint8_t *k = reinterpret_cast<const uint8_t*>(aData);
|
|
uint32_t a, b, c, len/*, length*/;
|
|
|
|
// length = PL_strlen(key);
|
|
/* Set up the internal state */
|
|
len = aSize;
|
|
a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
|
|
c = aInitval; /* variable initialization of internal state */
|
|
|
|
/*---------------------------------------- handle most of the key */
|
|
while (len >= 12)
|
|
{
|
|
a += k[0] + (uint32_t(k[1])<<8) + (uint32_t(k[2])<<16) + (uint32_t(k[3])<<24);
|
|
b += k[4] + (uint32_t(k[5])<<8) + (uint32_t(k[6])<<16) + (uint32_t(k[7])<<24);
|
|
c += k[8] + (uint32_t(k[9])<<8) + (uint32_t(k[10])<<16) + (uint32_t(k[11])<<24);
|
|
hashmix(a, b, c);
|
|
k += 12; len -= 12;
|
|
}
|
|
|
|
/*------------------------------------- handle the last 11 bytes */
|
|
c += aSize;
|
|
switch(len) { /* all the case statements fall through */
|
|
case 11: c += (uint32_t(k[10])<<24);
|
|
case 10: c += (uint32_t(k[9])<<16);
|
|
case 9 : c += (uint32_t(k[8])<<8);
|
|
/* the low-order byte of c is reserved for the length */
|
|
case 8 : b += (uint32_t(k[7])<<24);
|
|
case 7 : b += (uint32_t(k[6])<<16);
|
|
case 6 : b += (uint32_t(k[5])<<8);
|
|
case 5 : b += k[4];
|
|
case 4 : a += (uint32_t(k[3])<<24);
|
|
case 3 : a += (uint32_t(k[2])<<16);
|
|
case 2 : a += (uint32_t(k[1])<<8);
|
|
case 1 : a += k[0];
|
|
/* case 0: nothing left to add */
|
|
}
|
|
hashmix(a, b, c);
|
|
|
|
return c;
|
|
}
|
|
|
|
CacheHashUtils::Hash16_t
|
|
CacheHashUtils::Hash16(const char *aData, uint32_t aSize, uint32_t aInitval)
|
|
{
|
|
Hash32_t hash = Hash(aData, aSize, aInitval);
|
|
return (hash & 0xFFFF);
|
|
}
|
|
|
|
} // net
|
|
} // mozilla
|
|
|