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101 lines
2.1 KiB
C++
101 lines
2.1 KiB
C++
//======= Copyright © Valve Corporation, All rights reserved. =================
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//
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// Public domain MurmurHash3 by Austin Appleby is a very solid general-purpose
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// hash with a 32-bit output. References:
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// http://code.google.com/p/smhasher/ (home of MurmurHash3)
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// https://sites.google.com/site/murmurhash/avalanche
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// http://www.strchr.com/hash_functions
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//
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//=============================================================================
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#ifndef MURMURHASH3_H
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#define MURMURHASH3_H
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#if defined(_WIN32)
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#pragma once
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#endif
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uint32 MurmurHash3_32( const void *key, size_t len, uint32 seed, bool bCaselessStringVariant = false );
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inline uint32 MurmurHash3String( const char *pszKey, size_t len )
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{
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return MurmurHash3_32( pszKey, len, 1047 /*anything will do for a seed*/, false );
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}
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inline uint32 MurmurHash3StringCaseless( const char *pszKey, size_t len )
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{
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return MurmurHash3_32( pszKey, len, 1047 /*anything will do for a seed*/, true );
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}
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inline uint32 MurmurHash3String( const char *pszKey )
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{
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return MurmurHash3String( pszKey, strlen( pszKey ) );
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}
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inline uint32 MurmurHash3StringCaseless( const char *pszKey )
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{
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return MurmurHash3StringCaseless( pszKey, strlen( pszKey ) );
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}
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template <typename T>
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inline uint32 MurmurHash3Item( const T &item )
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{
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return MurmurHash3_32( &item, sizeof(item), 1047 );
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}
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inline uint32 MurmurHash3Int( uint32 h )
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{
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h ^= h >> 16;
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h *= 0x85ebca6b;
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h ^= h >> 13;
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h *= 0xc2b2ae35;
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h ^= h >> 16;
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return h;
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}
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template <>
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inline uint32 MurmurHash3Item( const uint32 &item )
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{
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return MurmurHash3Int( item );
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}
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template <>
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inline uint32 MurmurHash3Item( const int32 &item )
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{
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return MurmurHash3Int( item );
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}
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template<typename T>
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struct MurmurHash3Functor
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{
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typedef uint32 TargetType;
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TargetType operator()(const T &key) const
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{
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return MurmurHash3Item( key );
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}
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};
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template<>
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struct MurmurHash3Functor<char *>
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{
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typedef uint32 TargetType;
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TargetType operator()(const char *key) const
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{
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return MurmurHash3String( key );
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}
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};
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template<>
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struct MurmurHash3Functor<const char *>
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{
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typedef uint32 TargetType;
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TargetType operator()(const char *key) const
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{
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return MurmurHash3String( key );
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}
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};
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#endif // MURMURHASH3_H
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