mirror of https://gitee.com/bigwinds/arangodb
70 lines
2.3 KiB
C
70 lines
2.3 KiB
C
/* The MIT License
|
|
|
|
Copyright (C) 2012 Zilong Tan (eric.zltan@gmail.com)
|
|
|
|
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 LIB_BASICS_FASTHASH_H
|
|
#define LIB_BASICS_FASTHASH_H 1
|
|
|
|
#include "Basics/Common.h"
|
|
|
|
static constexpr uint64_t fasthash_m = 0x880355f21e6d1965ULL;
|
|
|
|
// Compression function for Merkle-Damgard construction.
|
|
// This function is generated using the framework provided.
|
|
static inline uint64_t fasthash_mix(uint64_t h) {
|
|
h ^= h >> 23;
|
|
h *= 0x2127599bf4325c37ULL;
|
|
h ^= h >> 47;
|
|
|
|
return h;
|
|
}
|
|
|
|
static inline uint64_t fasthash64_uint64(uint64_t value, uint64_t seed) {
|
|
uint64_t h = seed ^ 4619197404915747624ULL; // this is h = seed ^ (sizeof(uint64_t) *
|
|
// m), but prevents VS warning C4307:
|
|
// integral constant overflow
|
|
h ^= fasthash_mix(value);
|
|
h *= fasthash_m;
|
|
|
|
return fasthash_mix(h);
|
|
}
|
|
|
|
/**
|
|
* fasthash32 - 32-bit implementation of fasthash
|
|
* @buf: data buffer
|
|
* @len: data size
|
|
* @seed: the seed
|
|
*/
|
|
uint32_t fasthash32(const void* buf, size_t len, uint32_t seed);
|
|
|
|
/**
|
|
* fasthash64 - 64-bit implementation of fasthash
|
|
* @buf: data buffer
|
|
* @len: data size
|
|
* @seed: the seed
|
|
*/
|
|
uint64_t fasthash64(const void* buf, size_t len, uint64_t seed);
|
|
|
|
#endif
|