nuclear@0: /*
nuclear@0: Open Asset Import Library (assimp)
nuclear@0: ----------------------------------------------------------------------
nuclear@0: 
nuclear@0: Copyright (c) 2006-2012, assimp team
nuclear@0: All rights reserved.
nuclear@0: 
nuclear@0: Redistribution and use of this software in source and binary forms, 
nuclear@0: with or without modification, are permitted provided that the 
nuclear@0: following conditions are met:
nuclear@0: 
nuclear@0: * Redistributions of source code must retain the above
nuclear@0:   copyright notice, this list of conditions and the
nuclear@0:   following disclaimer.
nuclear@0: 
nuclear@0: * Redistributions in binary form must reproduce the above
nuclear@0:   copyright notice, this list of conditions and the
nuclear@0:   following disclaimer in the documentation and/or other
nuclear@0:   materials provided with the distribution.
nuclear@0: 
nuclear@0: * Neither the name of the assimp team, nor the names of its
nuclear@0:   contributors may be used to endorse or promote products
nuclear@0:   derived from this software without specific prior
nuclear@0:   written permission of the assimp team.
nuclear@0: 
nuclear@0: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
nuclear@0: "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
nuclear@0: LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
nuclear@0: A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
nuclear@0: OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
nuclear@0: SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
nuclear@0: LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
nuclear@0: DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
nuclear@0: THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
nuclear@0: (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
nuclear@0: OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
nuclear@0: 
nuclear@0: ----------------------------------------------------------------------
nuclear@0: */
nuclear@0: 
nuclear@0: #ifndef AI_HASH_H_INCLUDED
nuclear@0: #define AI_HASH_H_INCLUDED
nuclear@0: 
nuclear@0: // ------------------------------------------------------------------------------------------------
nuclear@0: // Hashing function taken from 
nuclear@0: // http://www.azillionmonkeys.com/qed/hash.html
nuclear@0: // (incremental version)
nuclear@0: //
nuclear@0: // This code is Copyright 2004-2008 by Paul Hsieh. It is used here in the belief that
nuclear@0: // Assimp's license is considered compatible with Pauls's derivative license as specified
nuclear@0: // on his web page.
nuclear@0: //
nuclear@0: // (stdint.h should have been been included here)
nuclear@0: // ------------------------------------------------------------------------------------------------
nuclear@0: #undef get16bits
nuclear@0: #if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
nuclear@0:   || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
nuclear@0: #define get16bits(d) (*((const uint16_t *) (d)))
nuclear@0: #endif
nuclear@0: 
nuclear@0: #if !defined (get16bits)
nuclear@0: #define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
nuclear@0:                        +(uint32_t)(((const uint8_t *)(d))[0]) )
nuclear@0: #endif
nuclear@0: 
nuclear@0: // ------------------------------------------------------------------------------------------------
nuclear@0: inline uint32_t SuperFastHash (const char * data, uint32_t len = 0, uint32_t hash = 0) {
nuclear@0: uint32_t tmp;
nuclear@0: int rem;
nuclear@0: 
nuclear@0:     if (!data) return 0;
nuclear@0: 	if (!len)len = (uint32_t)::strlen(data);
nuclear@0: 
nuclear@0:     rem = len & 3;
nuclear@0:     len >>= 2;
nuclear@0: 
nuclear@0:     /* Main loop */
nuclear@0:     for (;len > 0; len--) {
nuclear@0:         hash  += get16bits (data);
nuclear@0:         tmp    = (get16bits (data+2) << 11) ^ hash;
nuclear@0:         hash   = (hash << 16) ^ tmp;
nuclear@0:         data  += 2*sizeof (uint16_t);
nuclear@0:         hash  += hash >> 11;
nuclear@0:     }
nuclear@0: 
nuclear@0:     /* Handle end cases */
nuclear@0:     switch (rem) {
nuclear@0:         case 3: hash += get16bits (data);
nuclear@0:                 hash ^= hash << 16;
nuclear@0:                 hash ^= data[sizeof (uint16_t)] << 18;
nuclear@0:                 hash += hash >> 11;
nuclear@0:                 break;
nuclear@0:         case 2: hash += get16bits (data);
nuclear@0:                 hash ^= hash << 11;
nuclear@0:                 hash += hash >> 17;
nuclear@0:                 break;
nuclear@0:         case 1: hash += *data;
nuclear@0:                 hash ^= hash << 10;
nuclear@0:                 hash += hash >> 1;
nuclear@0:     }
nuclear@0: 
nuclear@0:     /* Force "avalanching" of final 127 bits */
nuclear@0:     hash ^= hash << 3;
nuclear@0:     hash += hash >> 5;
nuclear@0:     hash ^= hash << 4;
nuclear@0:     hash += hash >> 17;
nuclear@0:     hash ^= hash << 25;
nuclear@0:     hash += hash >> 6;
nuclear@0: 
nuclear@0:     return hash;
nuclear@0: }
nuclear@0: 
nuclear@0: #endif // !! AI_HASH_H_INCLUDED