diff --git a/sources/MurmurHash2/MurmurHash2.cpp b/sources/MurmurHash2/MurmurHash2.cpp new file mode 100644 index 00000000..598a8754 --- /dev/null +++ b/sources/MurmurHash2/MurmurHash2.cpp @@ -0,0 +1,71 @@ +//----------------------------------------------------------------------------- +// MurmurHash2, by Austin Appleby + +// 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. + +#include "MurmurHash2.h" + +namespace murmurhash2 { + +unsigned int MurmurHash2 ( const void * key, int len, unsigned int seed ) +{ + // '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 murmurhash2 { + diff --git a/sources/MurmurHash2/MurmurHash2.h b/sources/MurmurHash2/MurmurHash2.h new file mode 100644 index 00000000..5fe3d33e --- /dev/null +++ b/sources/MurmurHash2/MurmurHash2.h @@ -0,0 +1,7 @@ +#pragma once + +namespace murmurhash2 { + +unsigned int MurmurHash2( const void * key, int len, unsigned int seed ); + +} diff --git a/versions.txt b/versions.txt index 6afa593d..9dcf5ae4 100644 --- a/versions.txt +++ b/versions.txt @@ -114,3 +114,7 @@ glslang (Built using https://github.com/YunHsiao/glslang/tree/build) android: 11.5.0 (commit: 1978c76) mac: 11.5.0 (commit: 1978c76) ios: 11.5.0 (commit: 1978c76) + +MurmurHash2 + all-platforms: (no version informantion): https://sites.google.com/site/murmurhash + \ No newline at end of file