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DependentExtensions/cat/hash/MurmurHash2.hpp

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+/*
+	Copyright (c) 2009-2010 Christopher A. Taylor.  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 the name of LibCat nor the names of its contributors may 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 HOLDER 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.
+*/
+
+/*
+    MurmurHash2 is a very fast noncryptographic 32/64-bit hash
+
+    Algorithm by Austin Appleby <aappleby@gmail.com>
+    http://murmurhash.googlepages.com/
+*/
+
+#ifndef CAT_MURMUR_HASH_2_HPP
+#define CAT_MURMUR_HASH_2_HPP
+
+#include <cat/Platform.hpp>
+
+namespace cat {
+
+
+// NOTE: Result is NOT endian-neutral.  Use getLE().
+u32 MurmurHash32(const void *key, int bytes, u32 seed);
+u64 MurmurHash64(const void *key, int bytes, u64 seed);
+
+
+class IncrementalMurmurHash32
+{
+	u32 _hash, _tail, _count, _size;
+
+    static const u32 M = 0x5bd1e995;
+    static const u32 R = 24;
+
+public:
+	void Begin(u32 seed = 0);
+	void Add(const void *data, int bytes);
+	u32 End();
+};
+
+
+class IncrementalMurmurHash64
+{
+	u32 _count;
+	u64 _hash, _tail, _size;
+
+    static const u64 M = 0xc6a4a7935bd1e995ULL;
+    static const u64 R = 47;
+
+public:
+	void Begin(u64 seed = 0);
+	void Add(const void *data, int bytes);
+	u64 End();
+};
+
+
+} // namespace cat
+
+#endif // CAT_MURMUR_HASH_2_HPP