+++ /dev/null
-
-/*] Copyright (c) 2009-2010, Charles McGarvey [**************************
-**] All rights reserved.
-*
-* vi:ts=4 sw=4 tw=75
-*
-* Distributable under the terms and conditions of the 2-clause BSD license;
-* see the file COPYING for a complete text of the license.
-*
-**************************************************************************/
-
-#include "Hash.hh"
-
-
-namespace Mf {
-
-
-// MurmurHash2, by Austin Appleby
-// http://murmurhash.googlepages.com/
-
-// This function is in the public domain.
-
-// Note - This code makes a few assumptions about how your machine behaves -
-
-// 1. We can read a 4-byte value from any address without crashing
-// 2. sizeof(int) == 4
-
-// And it has a few limitations -
-
-// 1. It will not work incrementally.
-// 2. It will not produce the same results on little-endian and big-endian
-// machines.
-
-unsigned getHash::operator()(const void* key, int len,
- unsigned int seed) const
-{
- // 'm' and 'r' are mixing constants generated offline.
- // They're not really 'magic', they just happen to work well.
-
- const unsigned int m = 0x5bd1e995;
- const int r = 24;
-
- // Initialize the hash to a 'random' value
-
- unsigned int h = seed ^ len;
-
- // Mix 4 bytes at a time into the hash
-
- const unsigned char* data = (const unsigned char*)key;
-
- while (len >= 4)
- {
- unsigned int k = *(unsigned int*)data;
-
- k *= m;
- k ^= k >> r;
- k *= m;
-
- h *= m;
- h ^= k;
-
- data += 4;
- len -= 4;
- }
-
- // Handle the last few bytes of the input array
-
- switch (len)
- {
- case 3: h ^= data[2] << 16;
- case 2: h ^= data[1] << 8;
- case 1: h ^= data[0];
- h *= m;
- };
-
- // Do a few final mixes of the hash to ensure the last few
- // bytes are well-incorporated.
-
- h ^= h >> 13;
- h *= m;
- h ^= h >> 15;
-
- return h;
-}
-
-
-} // namespace Mf
-