114 lines
4.0 KiB
C
114 lines
4.0 KiB
C
/*
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Open Asset Import Library (ASSIMP)
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----------------------------------------------------------------------
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Copyright (c) 2006-2010, ASSIMP Development Team
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All rights reserved.
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Redistribution and use of this software in source and binary forms,
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with or without modification, are permitted provided that the
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following conditions are met:
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* Redistributions of source code must retain the above
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copyright notice, this list of conditions and the
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following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the
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following disclaimer in the documentation and/or other
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materials provided with the distribution.
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* Neither the name of the ASSIMP team, nor the names of its
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contributors may be used to endorse or promote products
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derived from this software without specific prior
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written permission of the ASSIMP Development Team.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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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
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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----------------------------------------------------------------------
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*/
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#ifndef AI_HASH_H_INCLUDED
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#define AI_HASH_H_INCLUDED
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// ------------------------------------------------------------------------------------------------
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// Hashing function taken from
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// http://www.azillionmonkeys.com/qed/hash.html
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// (incremental version)
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//
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// This code is Copyright 2004-2008 by Paul Hsieh. It is used here in the belief that
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// Assimp's license is considered compatible with Pauls's derivative license as specified
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// on his web page.
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//
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// (stdint.h should have been been included here)
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// ------------------------------------------------------------------------------------------------
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#undef get16bits
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#if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
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|| defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
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#define get16bits(d) (*((const uint16_t *) (d)))
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#endif
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#if !defined (get16bits)
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#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
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+(uint32_t)(((const uint8_t *)(d))[0]) )
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#endif
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// ------------------------------------------------------------------------------------------------
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inline uint32_t SuperFastHash (const char * data, uint32_t len = 0, uint32_t hash = 0) {
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uint32_t tmp;
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int rem;
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if (!data) return 0;
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if (!len)len = (uint32_t)::strlen(data);
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rem = len & 3;
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len >>= 2;
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/* Main loop */
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for (;len > 0; len--) {
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hash += get16bits (data);
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tmp = (get16bits (data+2) << 11) ^ hash;
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hash = (hash << 16) ^ tmp;
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data += 2*sizeof (uint16_t);
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hash += hash >> 11;
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}
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/* Handle end cases */
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switch (rem) {
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case 3: hash += get16bits (data);
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hash ^= hash << 16;
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hash ^= data[sizeof (uint16_t)] << 18;
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hash += hash >> 11;
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break;
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case 2: hash += get16bits (data);
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hash ^= hash << 11;
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hash += hash >> 17;
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break;
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case 1: hash += *data;
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hash ^= hash << 10;
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hash += hash >> 1;
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}
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/* Force "avalanching" of final 127 bits */
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hash ^= hash << 3;
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hash += hash >> 5;
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hash ^= hash << 4;
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hash += hash >> 17;
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hash ^= hash << 25;
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hash += hash >> 6;
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return hash;
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}
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#endif // !! AI_HASH_H_INCLUDED
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