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104 lines
3.3 KiB
C
104 lines
3.3 KiB
C
/*
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* Copyright 2010 Andrea Mazzoleni. 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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*
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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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*
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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 ANDREA MAZZOLENI AND CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL ANDREA MAZZOLENI OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/** \file
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* Hash functions for the use with ::tommy_hashtable, ::tommy_hashdyn and ::tommy_hashlin.
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*/
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#ifndef __TOMMYHASH_H
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#define __TOMMYHASH_H
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#include "tommytypes.h"
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/******************************************************************************/
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/* hash */
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/**
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* Hash type used in hashtables.
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*/
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typedef tommy_key_t tommy_hash_t;
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/**
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* Hash function.
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* Robert Jenkins "lookup3" hash,
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* from http://www.burtleburtle.net/bob/hash/doobs.html, function hashlittle().
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* \note
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* This function is platform independent as it read always in little endian format.
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* \param init_val Initial value. You can use this to concatenate hash. Otherwise set it at 0.
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* \param void_key Key to hash.
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* \param key_len Length of the key.
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* \return The 32 bit hash value.
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*/
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tommy_uint32_t tommy_hash_u32(tommy_uint32_t init_val, const void* void_key, tommy_size_t key_len);
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/**
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* Hash function for 64 bits.
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* Robert Jenkins "lookup3" hash,
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* from http://www.burtleburtle.net/bob/hash/doobs.html, function hashlittle2().
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* \note
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* This function is platform independent as it read always in little endian format.
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*/
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tommy_uint64_t tommy_hash_u64(tommy_uint64_t init_val, const void* void_key, tommy_size_t key_len);
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/**
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* Integer hash of 32 bits.
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* Robert Jenkins "4-byte Integer Hashing",
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* from http://burtleburtle.net/bob/hash/integer.html
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*/
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tommy_inline tommy_uint32_t tommy_inthash_u32(tommy_uint32_t key)
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{
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key -= key << 6;
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key ^= key >> 17;
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key -= key << 9;
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key ^= key << 4;
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key -= key << 3;
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key ^= key << 10;
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key ^= key >> 15;
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return key;
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}
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/**
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* Integer hash of 64 bits.
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* Thomas Wang "Integer Hash Function",
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* from http://www.cris.com/~Ttwang/tech/inthash.htm
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*/
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tommy_inline tommy_uint64_t tommy_inthash_u64(tommy_uint64_t key)
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{
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key = ~key + (key << 21);
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key = key ^ (key >> 24);
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key = key + (key << 3) + (key << 8);
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key = key ^ (key >> 14);
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key = key + (key << 2) + (key << 4);
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key = key ^ (key >> 28);
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key = key + (key << 31);
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return key;
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}
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#endif
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