diff options
Diffstat (limited to 'lib/fnv/hash_64.c')
| -rw-r--r-- | lib/fnv/hash_64.c | 312 |
1 files changed, 0 insertions, 312 deletions
diff --git a/lib/fnv/hash_64.c b/lib/fnv/hash_64.c deleted file mode 100644 index 4338605dca..0000000000 --- a/lib/fnv/hash_64.c +++ /dev/null @@ -1,312 +0,0 @@ -/* - * hash_64 - 64 bit Fowler/Noll/Vo-0 hash code - * - * @(#) $Revision: 5.1 $ - * @(#) $Id: hash_64.c,v 5.1 2009/06/30 09:01:38 chongo Exp $ - * @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64.c,v $ - * - *** - * - * Fowler/Noll/Vo hash - * - * The basis of this hash algorithm was taken from an idea sent - * as reviewer comments to the IEEE POSIX P1003.2 committee by: - * - * Phong Vo (http://www.research.att.com/info/kpv/) - * Glenn Fowler (http://www.research.att.com/~gsf/) - * - * In a subsequent ballot round: - * - * Landon Curt Noll (http://www.isthe.com/chongo/) - * - * improved on their algorithm. Some people tried this hash - * and found that it worked rather well. In an EMail message - * to Landon, they named it the ``Fowler/Noll/Vo'' or FNV hash. - * - * FNV hashes are designed to be fast while maintaining a low - * collision rate. The FNV speed allows one to quickly hash lots - * of data while maintaining a reasonable collision rate. See: - * - * http://www.isthe.com/chongo/tech/comp/fnv/index.html - * - * for more details as well as other forms of the FNV hash. - * - *** - * - * NOTE: The FNV-0 historic hash is not recommended. One should use - * the FNV-1 hash instead. - * - * To use the 64 bit FNV-0 historic hash, pass FNV0_64_INIT as the - * Fnv64_t hashval argument to fnv_64_buf() or fnv_64_str(). - * - * To use the recommended 64 bit FNV-1 hash, pass FNV1_64_INIT as the - * Fnv64_t hashval argument to fnv_64_buf() or fnv_64_str(). - * - *** - * - * 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. - * - * By: - * chongo <Landon Curt Noll> /\oo/\ - * http://www.isthe.com/chongo/ - * - * Share and Enjoy! :-) - */ - -#include <stdlib.h> -#include "fnv.h" - - -/* - * FNV-0 defines the initial basis to be zero - */ -#if !defined(HAVE_64BIT_LONG_LONG) -const Fnv64_t fnv0_64_init = { 0UL, 0UL }; -#endif /* ! HAVE_64BIT_LONG_LONG */ - - -/* - * FNV-1 defines the initial basis to be non-zero - */ -#if !defined(HAVE_64BIT_LONG_LONG) -const Fnv64_t fnv1_64_init = { 0x84222325UL, 0xcbf29ce4UL }; -#endif /* ! HAVE_64BIT_LONG_LONG */ - - -/* - * 64 bit magic FNV-0 and FNV-1 prime - */ -#if defined(HAVE_64BIT_LONG_LONG) -#define FNV_64_PRIME ((Fnv64_t)0x100000001b3ULL) -#else /* HAVE_64BIT_LONG_LONG */ -#define FNV_64_PRIME_LOW ((unsigned long)0x1b3) /* lower bits of FNV prime */ -#define FNV_64_PRIME_SHIFT (8) /* top FNV prime shift above 2^32 */ -#endif /* HAVE_64BIT_LONG_LONG */ - - -/* - * fnv_64_buf - perform a 64 bit Fowler/Noll/Vo hash on a buffer - * - * input: - * buf - start of buffer to hash - * len - length of buffer in octets - * hval - previous hash value or 0 if first call - * - * returns: - * 64 bit hash as a static hash type - * - * NOTE: To use the 64 bit FNV-0 historic hash, use FNV0_64_INIT as the hval - * argument on the first call to either fnv_64_buf() or fnv_64_str(). - * - * NOTE: To use the recommended 64 bit FNV-1 hash, use FNV1_64_INIT as the hval - * argument on the first call to either fnv_64_buf() or fnv_64_str(). - */ -Fnv64_t -fnv_64_buf(void *buf, size_t len, Fnv64_t hval) -{ - unsigned char *bp = (unsigned char *)buf; /* start of buffer */ - unsigned char *be = bp + len; /* beyond end of buffer */ - -#if defined(HAVE_64BIT_LONG_LONG) - - /* - * FNV-1 hash each octet of the buffer - */ - while (bp < be) { - - /* multiply by the 64 bit FNV magic prime mod 2^64 */ -#if defined(NO_FNV_GCC_OPTIMIZATION) - hval *= FNV_64_PRIME; -#else /* NO_FNV_GCC_OPTIMIZATION */ - hval += (hval << 1) + (hval << 4) + (hval << 5) + - (hval << 7) + (hval << 8) + (hval << 40); -#endif /* NO_FNV_GCC_OPTIMIZATION */ - - /* xor the bottom with the current octet */ - hval ^= (Fnv64_t)*bp++; - } - -#else /* HAVE_64BIT_LONG_LONG */ - - unsigned long val[4]; /* hash value in base 2^16 */ - unsigned long tmp[4]; /* tmp 64 bit value */ - - /* - * Convert Fnv64_t hval into a base 2^16 array - */ - val[0] = hval.w32[0]; - val[1] = (val[0] >> 16); - val[0] &= 0xffff; - val[2] = hval.w32[1]; - val[3] = (val[2] >> 16); - val[2] &= 0xffff; - - /* - * FNV-1 hash each octet of the buffer - */ - while (bp < be) { - - /* - * multiply by the 64 bit FNV magic prime mod 2^64 - * - * Using 0x100000001b3 we have the following digits base 2^16: - * - * 0x0 0x100 0x0 0x1b3 - * - * which is the same as: - * - * 0x0 1<<FNV_64_PRIME_SHIFT 0x0 FNV_64_PRIME_LOW - */ - /* multiply by the lowest order digit base 2^16 */ - tmp[0] = val[0] * FNV_64_PRIME_LOW; - tmp[1] = val[1] * FNV_64_PRIME_LOW; - tmp[2] = val[2] * FNV_64_PRIME_LOW; - tmp[3] = val[3] * FNV_64_PRIME_LOW; - /* multiply by the other non-zero digit */ - tmp[2] += val[0] << FNV_64_PRIME_SHIFT; /* tmp[2] += val[0] * 0x100 */ - tmp[3] += val[1] << FNV_64_PRIME_SHIFT; /* tmp[3] += val[1] * 0x100 */ - /* propagate carries */ - tmp[1] += (tmp[0] >> 16); - val[0] = tmp[0] & 0xffff; - tmp[2] += (tmp[1] >> 16); - val[1] = tmp[1] & 0xffff; - val[3] = tmp[3] + (tmp[2] >> 16); - val[2] = tmp[2] & 0xffff; - /* - * Doing a val[3] &= 0xffff; is not really needed since it simply - * removes multiples of 2^64. We can discard these excess bits - * outside of the loop when we convert to Fnv64_t. - */ - - /* xor the bottom with the current octet */ - val[0] ^= (unsigned long)*bp++; - } - - /* - * Convert base 2^16 array back into an Fnv64_t - */ - hval.w32[1] = ((val[3]<<16) | val[2]); - hval.w32[0] = ((val[1]<<16) | val[0]); - -#endif /* HAVE_64BIT_LONG_LONG */ - - /* return our new hash value */ - return hval; -} - - -/* - * fnv_64_str - perform a 64 bit Fowler/Noll/Vo hash on a buffer - * - * input: - * buf - start of buffer to hash - * hval - previous hash value or 0 if first call - * - * returns: - * 64 bit hash as a static hash type - * - * NOTE: To use the 64 bit FNV-0 historic hash, use FNV0_64_INIT as the hval - * argument on the first call to either fnv_64_buf() or fnv_64_str(). - * - * NOTE: To use the recommended 64 bit FNV-1 hash, use FNV1_64_INIT as the hval - * argument on the first call to either fnv_64_buf() or fnv_64_str(). - */ -Fnv64_t -fnv_64_str(char *str, Fnv64_t hval) -{ - unsigned char *s = (unsigned char *)str; /* unsigned string */ - -#if defined(HAVE_64BIT_LONG_LONG) - - /* - * FNV-1 hash each octet of the string - */ - while (*s) { - - /* multiply by the 64 bit FNV magic prime mod 2^64 */ -#if defined(NO_FNV_GCC_OPTIMIZATION) - hval *= FNV_64_PRIME; -#else /* NO_FNV_GCC_OPTIMIZATION */ - hval += (hval << 1) + (hval << 4) + (hval << 5) + - (hval << 7) + (hval << 8) + (hval << 40); -#endif /* NO_FNV_GCC_OPTIMIZATION */ - - /* xor the bottom with the current octet */ - hval ^= (Fnv64_t)*s++; - } - -#else /* !HAVE_64BIT_LONG_LONG */ - - unsigned long val[4]; /* hash value in base 2^16 */ - unsigned long tmp[4]; /* tmp 64 bit value */ - - /* - * Convert Fnv64_t hval into a base 2^16 array - */ - val[0] = hval.w32[0]; - val[1] = (val[0] >> 16); - val[0] &= 0xffff; - val[2] = hval.w32[1]; - val[3] = (val[2] >> 16); - val[2] &= 0xffff; - - /* - * FNV-1 hash each octet of the string - */ - while (*s) { - - /* - * multiply by the 64 bit FNV magic prime mod 2^64 - * - * Using 1099511628211, we have the following digits base 2^16: - * - * 0x0 0x100 0x0 0x1b3 - * - * which is the same as: - * - * 0x0 1<<FNV_64_PRIME_SHIFT 0x0 FNV_64_PRIME_LOW - */ - /* multiply by the lowest order digit base 2^16 */ - tmp[0] = val[0] * FNV_64_PRIME_LOW; - tmp[1] = val[1] * FNV_64_PRIME_LOW; - tmp[2] = val[2] * FNV_64_PRIME_LOW; - tmp[3] = val[3] * FNV_64_PRIME_LOW; - /* multiply by the other non-zero digit */ - tmp[2] += val[0] << FNV_64_PRIME_SHIFT; /* tmp[2] += val[0] * 0x100 */ - tmp[3] += val[1] << FNV_64_PRIME_SHIFT; /* tmp[3] += val[1] * 0x100 */ - /* propagate carries */ - tmp[1] += (tmp[0] >> 16); - val[0] = tmp[0] & 0xffff; - tmp[2] += (tmp[1] >> 16); - val[1] = tmp[1] & 0xffff; - val[3] = tmp[3] + (tmp[2] >> 16); - val[2] = tmp[2] & 0xffff; - /* - * Doing a val[3] &= 0xffff; is not really needed since it simply - * removes multiples of 2^64. We can discard these excess bits - * outside of the loop when we convert to Fnv64_t. - */ - - /* xor the bottom with the current octet */ - val[0] ^= (unsigned long)(*s++); - } - - /* - * Convert base 2^16 array back into an Fnv64_t - */ - hval.w32[1] = ((val[3]<<16) | val[2]); - hval.w32[0] = ((val[1]<<16) | val[0]); - -#endif /* !HAVE_64BIT_LONG_LONG */ - - /* return our new hash value */ - return hval; -} |