69 lines
1.3 KiB
C
69 lines
1.3 KiB
C
/*-
|
|
* Fowler / Noll / Vo Hash (FNV Hash)
|
|
* http://www.isthe.com/chongo/tech/comp/fnv/
|
|
*
|
|
* This is an implementation of the algorithms posted above.
|
|
* This file is placed in the public domain by Peter Wemm.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
typedef u_int32_t Fnv32_t;
|
|
typedef u_int64_t Fnv64_t;
|
|
|
|
#define FNV1_32_INIT ((Fnv32_t) 33554467UL)
|
|
#define FNV1_64_INIT ((Fnv64_t) 0xcbf29ce484222325ULL)
|
|
|
|
#define FNV_32_PRIME ((Fnv32_t) 0x01000193UL)
|
|
#define FNV_64_PRIME ((Fnv64_t) 0x100000001b3ULL)
|
|
|
|
static __inline Fnv32_t
|
|
fnv_32_buf(const void *buf, size_t len, Fnv32_t hval)
|
|
{
|
|
const u_int8_t *s = (const u_int8_t *)buf;
|
|
|
|
while (len-- != 0) {
|
|
hval *= FNV_32_PRIME;
|
|
hval ^= *s++;
|
|
}
|
|
return hval;
|
|
}
|
|
|
|
static __inline Fnv32_t
|
|
fnv_32_str(const char *str, Fnv32_t hval)
|
|
{
|
|
const u_int8_t *s = (const u_int8_t *)str;
|
|
Fnv32_t c;
|
|
|
|
while ((c = *s++) != 0) {
|
|
hval *= FNV_32_PRIME;
|
|
hval ^= c;
|
|
}
|
|
return hval;
|
|
}
|
|
|
|
static __inline Fnv64_t
|
|
fnv_64_buf(const void *buf, size_t len, Fnv64_t hval)
|
|
{
|
|
const u_int8_t *s = (const u_int8_t *)buf;
|
|
|
|
while (len-- != 0) {
|
|
hval *= FNV_64_PRIME;
|
|
hval ^= *s++;
|
|
}
|
|
return hval;
|
|
}
|
|
|
|
static __inline Fnv64_t
|
|
fnv_64_str(const char *str, Fnv64_t hval)
|
|
{
|
|
const u_int8_t *s = (const u_int8_t *)str;
|
|
u_register_t c; /* 32 bit on i386, 64 bit on alpha,ia64 */
|
|
|
|
while ((c = *s++) != 0) {
|
|
hval *= FNV_64_PRIME;
|
|
hval ^= c;
|
|
}
|
|
return hval;
|
|
}
|