/*- * Copyright (c) 2013, Joseph Koshy * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer * in this position and unchanged. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * An implementation of the Fowler-Noll-Vo hash function. * * References: * - http://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function * - http://www.isthe.com/chongo/tech/comp/fnv/ */ #include <sys/types.h> #include <limits.h> #include "_libelftc.h" ELFTC_VCSID("$Id: libelftc_hash.c 2870 2013-01-07 10:38:43Z jkoshy $"); /* * Use the size of an 'int' to determine the magic numbers used by the * hash function. */ #if INT_MAX == 2147483647UL #define FNV_PRIME 16777619UL #define FNV_OFFSET 2166136261UL #elif INT_MAX == 18446744073709551615ULL #define FNV_PRIME 1099511628211ULL #define FNV_OFFSET 14695981039346656037ULL #else #error sizeof(int) is unknown. #endif unsigned int libelftc_hash_string(const char *s) { char c; unsigned int hash; for (hash = FNV_OFFSET; (c = *s) != '\0'; s++) { hash ^= c; hash *= FNV_PRIME; } return (hash); } |