167 lines
3.3 KiB
C
167 lines
3.3 KiB
C
/*
|
|
HashFNV - FNV hash functions
|
|
|
|
adapted by Lumiera.org
|
|
2010, 2011 Christian Thaeter <ct@pipapo.org>
|
|
|
|
original by chongo <Landon Curt Noll> /\oo/\
|
|
http://www.isthe.com/chongo/
|
|
|
|
Please do not copyright this code. This code is in the public domain.
|
|
|
|
LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
|
|
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
|
|
EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
|
|
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
|
|
USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
|
|
OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
|
|
PERFORMANCE OF THIS SOFTWARE.
|
|
|
|
Share and Enjoy! :-)
|
|
|
|
* *****************************************************/
|
|
|
|
|
|
/** @file hash-fnv.c
|
|
** Implementation of FNV ("Fowler-Noll-Vo") hashing functions.
|
|
** @remarks code for this implementation is public domain
|
|
*/
|
|
|
|
|
|
#include "lib/hash-fnv.h"
|
|
|
|
#include <nobug.h>
|
|
|
|
|
|
|
|
uint64_t
|
|
hash_fnv64a_buf (const void *buf, size_t len, uint64_t hval)
|
|
{
|
|
const unsigned char *bp = (const unsigned char *)buf;
|
|
const unsigned char *be = bp + len;
|
|
while (bp < be)
|
|
{
|
|
hval ^= (uint64_t)*bp++;
|
|
hval *= HASH_FNV64_PRIME;
|
|
}
|
|
|
|
return hval;
|
|
}
|
|
|
|
|
|
|
|
uint32_t
|
|
hash_fnv32a_buf (const void *buf, size_t len, uint32_t hval)
|
|
{
|
|
const unsigned char *bp = (const unsigned char *)buf;
|
|
const unsigned char *be = bp + len;
|
|
while (bp < be)
|
|
{
|
|
hval ^= (uint32_t)*bp++;
|
|
hval *= HASH_FNV32_PRIME;
|
|
}
|
|
|
|
return hval;
|
|
}
|
|
|
|
|
|
uint64_t
|
|
hash_fnv64a_strn (const char* str, size_t len, uint64_t hval)
|
|
{
|
|
const unsigned char *bp = (const unsigned char *)str;
|
|
if (bp)
|
|
while (*bp && len--)
|
|
{
|
|
hval ^= (uint64_t)*bp++;
|
|
hval *= HASH_FNV64_PRIME;
|
|
}
|
|
|
|
return hval;
|
|
}
|
|
|
|
|
|
|
|
uint32_t
|
|
hash_fnv32a_strn (const char* str, size_t len, uint32_t hval)
|
|
{
|
|
const unsigned char *bp = (const unsigned char *)str;
|
|
if (bp)
|
|
while (*bp && len--)
|
|
{
|
|
hval ^= (uint32_t)*bp++;
|
|
hval *= HASH_FNV32_PRIME;
|
|
}
|
|
|
|
return hval;
|
|
}
|
|
|
|
|
|
|
|
uint64_t
|
|
hash_fnv64_xorfold (uint64_t hash, int bits)
|
|
{
|
|
REQUIRE(bits <= 64);
|
|
|
|
bits = 64-bits;
|
|
|
|
uint64_t mask = ~0ULL>>bits;
|
|
for (int todo = 32; bits && todo; todo >>= 1)
|
|
if (bits >= todo)
|
|
{
|
|
hash = hash ^ hash>>todo;
|
|
bits-=todo;
|
|
}
|
|
|
|
return hash & mask;
|
|
}
|
|
|
|
|
|
uint32_t
|
|
hash_fnv32_xorfold (uint32_t hash, int bits)
|
|
{
|
|
REQUIRE (bits <= 32);
|
|
|
|
bits = 32-bits;
|
|
|
|
uint32_t mask = ~0ULL>>bits;
|
|
for (int todo = 16; bits && todo; todo >>= 1)
|
|
if (bits >= todo)
|
|
{
|
|
hash = hash ^ hash>>todo;
|
|
bits-=todo;
|
|
}
|
|
|
|
return hash & mask;
|
|
}
|
|
|
|
|
|
uint64_t
|
|
hash_fnv64_retry (uint64_t hash, uint64_t limit)
|
|
{
|
|
uint64_t retry_level= (UINT64_MAX / limit) * limit;
|
|
|
|
while (hash >= retry_level)
|
|
hash = (hash * HASH_FNV64_PRIME) + HASH_FNV64_BASE;
|
|
|
|
return hash % limit;
|
|
}
|
|
|
|
|
|
uint32_t
|
|
hash_fnv32_retry (uint64_t hash, uint32_t limit)
|
|
{
|
|
uint32_t retry_level= (UINT32_MAX / limit) * limit;
|
|
|
|
while (hash >= retry_level)
|
|
hash = (hash * HASH_FNV32_PRIME) + HASH_FNV32_BASE;
|
|
|
|
return hash % limit;
|
|
}
|
|
|
|
/*
|
|
// Local Variables:
|
|
// mode: C
|
|
// c-file-style: "gnu"
|
|
// indent-tabs-mode: nil
|
|
// End:
|
|
*/
|