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- // Copyright (c) 2010, Paul Hsieh
- // All rights reserved.
- //
- // Redistribution and use in source and binary forms, with or without
- // modification, are permitted provided that the following conditions are met:
- //
- // * Redistributions of source code must retain the above copyright notice, this
- // list of conditions and the following disclaimer.
- // * Redistributions in binary form must reproduce the above copyright notice,
- // this list of conditions and the following disclaimer in the documentation
- // and/or other materials provided with the distribution.
- // * Neither my name, Paul Hsieh, nor the names of any other contributors to the
- // code use may not be used to endorse or promote products derived from this
- // software without specific prior written permission.
- //
- // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
- // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- // POSSIBILITY OF SUCH DAMAGE.
- #include <stdint.h>
- #include <stdlib.h>
- #undef get16bits
- #if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
- || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
- #define get16bits(d) (*((const uint16_t *) (d)))
- #endif
- #if !defined (get16bits)
- #define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
- +(uint32_t)(((const uint8_t *)(d))[0]) )
- #endif
- uint32_t SuperFastHash (const char * data, int len) {
- uint32_t hash = (uint32_t)len, tmp;
- int rem;
- if (len <= 0 || data == NULL) return 0;
- rem = len & 3;
- len >>= 2;
- /* Main loop */
- for (;len > 0; len--) {
- hash += get16bits (data);
- tmp = (uint32_t)(get16bits (data+2) << 11) ^ hash;
- hash = (hash << 16) ^ tmp;
- data += 2*sizeof (uint16_t);
- hash += hash >> 11;
- }
- /* Handle end cases */
- switch (rem) {
- case 3: hash += get16bits (data);
- hash ^= hash << 16;
- hash ^=
- (uint32_t)(((signed char)data[sizeof (uint16_t)]) << 18);
- hash += hash >> 11;
- break;
- case 2: hash += get16bits (data);
- hash ^= hash << 11;
- hash += hash >> 17;
- break;
- case 1: hash += (uint32_t)((signed char)*data);
- hash ^= hash << 10;
- hash += hash >> 1;
- }
- /* Force "avalanching" of final 127 bits */
- hash ^= hash << 3;
- hash += hash >> 5;
- hash ^= hash << 4;
- hash += hash >> 17;
- hash ^= hash << 25;
- hash += hash >> 6;
- return hash;
- }
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