1 /* 2 Open Asset Import Library (assimp) 3 ---------------------------------------------------------------------- 4 5 Copyright (c) 2006-2016, assimp team 6 All rights reserved. 7 8 Redistribution and use of this software in source and binary forms, 9 with or without modification, are permitted provided that the 10 following conditions are met: 11 12 * Redistributions of source code must retain the above 13 copyright notice, this list of conditions and the 14 following disclaimer. 15 16 * Redistributions in binary form must reproduce the above 17 copyright notice, this list of conditions and the 18 following disclaimer in the documentation and/or other 19 materials provided with the distribution. 20 21 * Neither the name of the assimp team, nor the names of its 22 contributors may be used to endorse or promote products 23 derived from this software without specific prior 24 written permission of the assimp team. 25 26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 27 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 28 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 29 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 30 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 31 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 32 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 36 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 38 ---------------------------------------------------------------------- 39 */ 40 41 #ifndef AI_HASH_H_INCLUDED 42 #define AI_HASH_H_INCLUDED 43 44 #include <stdint.h> 45 #include <string.h> 46 47 // ------------------------------------------------------------------------------------------------ 48 // Hashing function taken from 49 // http://www.azillionmonkeys.com/qed/hash.html 50 // (incremental version) 51 // 52 // This code is Copyright 2004-2008 by Paul Hsieh. It is used here in the belief that 53 // Assimp's license is considered compatible with Pauls's derivative license as specified 54 // on his web page. 55 // 56 // (stdint.h should have been been included here) 57 // ------------------------------------------------------------------------------------------------ 58 #undef get16bits 59 #if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \ 60 || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__) 61 #define get16bits(d) (*((const uint16_t *) (d))) 62 #endif 63 64 #if !defined (get16bits) 65 #define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\ 66 +(uint32_t)(((const uint8_t *)(d))[0]) ) 67 #endif 68 69 // ------------------------------------------------------------------------------------------------ 70 inline uint32_t SuperFastHash (const char * data, uint32_t len = 0, uint32_t hash = 0) { 71 uint32_t tmp; 72 int rem; 73 74 if (!data) return 0; 75 if (!len)len = (uint32_t)::strlen(data); 76 77 rem = len & 3; 78 len >>= 2; 79 80 /* Main loop */ 81 for (;len > 0; len--) { 82 hash += get16bits (data); 83 tmp = (get16bits (data+2) << 11) ^ hash; 84 hash = (hash << 16) ^ tmp; 85 data += 2*sizeof (uint16_t); 86 hash += hash >> 11; 87 } 88 89 /* Handle end cases */ 90 switch (rem) { 91 case 3: hash += get16bits (data); 92 hash ^= hash << 16; 93 hash ^= data[sizeof (uint16_t)] << 18; 94 hash += hash >> 11; 95 break; 96 case 2: hash += get16bits (data); 97 hash ^= hash << 11; 98 hash += hash >> 17; 99 break; 100 case 1: hash += *data; 101 hash ^= hash << 10; 102 hash += hash >> 1; 103 } 104 105 /* Force "avalanching" of final 127 bits */ 106 hash ^= hash << 3; 107 hash += hash >> 5; 108 hash ^= hash << 4; 109 hash += hash >> 17; 110 hash ^= hash << 25; 111 hash += hash >> 6; 112 113 return hash; 114 } 115 116 #endif // !! AI_HASH_H_INCLUDED 117