1/* 2 * fnv - Fowler/Noll/Vo- hash code 3 * 4 * @(#) $Revision: 5.4 $ 5 * @(#) $Id: fnv.h,v 5.4 2009/07/30 22:49:13 chongo Exp $ 6 * @(#) $Source: /usr/local/src/cmd/fnv/RCS/fnv.h,v $ 7 * 8 *** 9 * 10 * Fowler/Noll/Vo- hash 11 * 12 * The basis of this hash algorithm was taken from an idea sent 13 * as reviewer comments to the IEEE POSIX P1003.2 committee by: 14 * 15 * Phong Vo (http://www.research.att.com/info/kpv/) 16 * Glenn Fowler (http://www.research.att.com/~gsf/) 17 * 18 * In a subsequent ballot round: 19 * 20 * Landon Curt Noll (http://www.isthe.com/chongo/) 21 * 22 * improved on their algorithm. Some people tried this hash 23 * and found that it worked rather well. In an EMail message 24 * to Landon, they named it the ``Fowler/Noll/Vo'' or FNV hash. 25 * 26 * FNV hashes are designed to be fast while maintaining a low 27 * collision rate. The FNV speed allows one to quickly hash lots 28 * of data while maintaining a reasonable collision rate. See: 29 * 30 * http://www.isthe.com/chongo/tech/comp/fnv/index.html 31 * 32 * for more details as well as other forms of the FNV hash. 33 * 34 *** 35 * 36 * NOTE: The FNV-0 historic hash is not recommended. One should use 37 * the FNV-1 hash instead. 38 * 39 * To use the 32 bit FNV-0 historic hash, pass FNV0_32_INIT as the 40 * Fnv32_t hashval argument to fnv_32_buf() or fnv_32_str(). 41 * 42 * To use the 64 bit FNV-0 historic hash, pass FNV0_64_INIT as the 43 * uint64_t hashval argument to fnv_64_buf() or fnv_64_str(). 44 * 45 * To use the recommended 32 bit FNV-1 hash, pass FNV1_32_INIT as the 46 * Fnv32_t hashval argument to fnv_32_buf() or fnv_32_str(). 47 * 48 * To use the recommended 64 bit FNV-1 hash, pass FNV1_64_INIT as the 49 * uint64_t hashval argument to fnv_64_buf() or fnv_64_str(). 50 * 51 * To use the recommended 32 bit FNV-1a hash, pass FNV1_32A_INIT as the 52 * Fnv32_t hashval argument to fnv_32a_buf() or fnv_32a_str(). 53 * 54 * To use the recommended 64 bit FNV-1a hash, pass FNV1A_64_INIT as the 55 * uint64_t hashval argument to fnv_64a_buf() or fnv_64a_str(). 56 * 57 *** 58 * 59 * Please do not copyright this code. This code is in the public domain. 60 * 61 * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 62 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO 63 * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR 64 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF 65 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR 66 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 67 * PERFORMANCE OF THIS SOFTWARE. 68 * 69 * By: 70 * chongo <Landon Curt Noll> /\oo/\ 71 * http://www.isthe.com/chongo/ 72 * 73 * Share and Enjoy! :-) 74 */ 75 76#if !defined(__FNV_H__) 77#define __FNV_H__ 78 79#include <sys/types.h> 80 81#define FNV_VERSION "5.0.2" /* @(#) FNV Version */ 82#include <inttypes.h> 83 84#define HAVE_64BIT_LONG_LONG 85 86#if defined(HAVE_64BIT_LONG_LONG) 87#define FNV1_64_INIT ((uint64_t)0xcbf29ce484222325ULL) 88#define FNV1A_64_INIT FNV1_64_INIT 89#else /* HAVE_64BIT_LONG_LONG */ 90extern const fnv1_64_init; 91extern const uint64_t fnv1a_64_init; 92#define FNV1_64_INIT (fnv1_64_init) 93#define FNV1A_64_INIT (fnv1a_64_init) 94#endif /* HAVE_64BIT_LONG_LONG */ 95 96extern uint64_t fnv_64a_str(char *buf, uint64_t hashval); 97#endif /* __FNV_H__ */ 98