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