janwas
a34b759720
. timer, config: fix definition of ALLOW_RDTSC . add movsx_be64 (for whirlpool), revise implementation, move to byte_order, add test . MAX -> std::max, remove those macros . add timestamp to system_info as requested by philip This was SVN commit r5050.
118 lines
2.2 KiB
C++
118 lines
2.2 KiB
C++
/**
|
|
* =========================================================================
|
|
* File : fnv_hash.h
|
|
* Project : 0 A.D.
|
|
* Description : Fowler/Noll/Vo string hash
|
|
* =========================================================================
|
|
*/
|
|
|
|
// license: GPL; see lib/license.txt
|
|
|
|
#include "precompiled.h"
|
|
|
|
|
|
// FNV1-A hash - good for strings.
|
|
// if len = 0 (default), treat buf as a C-string;
|
|
// otherwise, hash <len> bytes of buf.
|
|
u32 fnv_hash(const void* buf, size_t len)
|
|
{
|
|
u32 h = 0x811c9dc5u;
|
|
// give distinct values for different length 0 buffers.
|
|
// value taken from FNV; it has no special significance.
|
|
|
|
const u8* p = (const u8*)buf;
|
|
|
|
// expected case: string
|
|
if(!len)
|
|
{
|
|
while(*p)
|
|
{
|
|
h ^= *p++;
|
|
h *= 0x01000193u;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
size_t bytes_left = len;
|
|
while(bytes_left != 0)
|
|
{
|
|
h ^= *p++;
|
|
h *= 0x01000193u;
|
|
|
|
bytes_left--;
|
|
}
|
|
}
|
|
|
|
return h;
|
|
}
|
|
|
|
|
|
// FNV1-A hash - good for strings.
|
|
// if len = 0 (default), treat buf as a C-string;
|
|
// otherwise, hash <len> bytes of buf.
|
|
u64 fnv_hash64(const void* buf, size_t len)
|
|
{
|
|
u64 h = 0xCBF29CE484222325ull;
|
|
// give distinct values for different length 0 buffers.
|
|
// value taken from FNV; it has no special significance.
|
|
|
|
const u8* p = (const u8*)buf;
|
|
|
|
// expected case: string
|
|
if(!len)
|
|
{
|
|
while(*p)
|
|
{
|
|
h ^= *p++;
|
|
h *= 0x100000001B3ull;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
size_t bytes_left = len;
|
|
while(bytes_left != 0)
|
|
{
|
|
h ^= *p++;
|
|
h *= 0x100000001B3ull;
|
|
|
|
bytes_left--;
|
|
}
|
|
}
|
|
|
|
return h;
|
|
}
|
|
|
|
|
|
// special version for strings: first converts to lowercase
|
|
// (useful for comparing mixed-case filenames).
|
|
// note: still need <len>, e.g. to support non-0-terminated strings
|
|
u32 fnv_lc_hash(const char* str, size_t len)
|
|
{
|
|
u32 h = 0x811c9dc5u;
|
|
// give distinct values for different length 0 buffers.
|
|
// value taken from FNV; it has no special significance.
|
|
|
|
// expected case: string
|
|
if(!len)
|
|
{
|
|
while(*str)
|
|
{
|
|
h ^= tolower(*str++);
|
|
h *= 0x01000193u;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
size_t bytes_left = len;
|
|
while(bytes_left != 0)
|
|
{
|
|
h ^= tolower(*str++);
|
|
h *= 0x01000193u;
|
|
|
|
bytes_left--;
|
|
}
|
|
}
|
|
|
|
return h;
|
|
}
|