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+/*
+ * Copyright (c) 2010, Andrea Mazzoleni. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. 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.
+ *
+ * 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.
+ */
+
+/** \file
+ * Hash functions for the use with ::tommy_hashtable, ::tommy_hashdyn and ::tommy_hashlin.
+ */
+
+#ifndef __TOMMYHASH_H
+#define __TOMMYHASH_H
+
+#include "tommytypes.h"
+
+/******************************************************************************/
+/* hash */
+
+/**
+ * Hash type used in hashtables.
+ */
+typedef tommy_key_t tommy_hash_t;
+
+/**
+ * Hash function with a 32 bits result.
+ * Implementation of the Robert Jenkins "lookup3" hash 32 bits version,
+ * from http://www.burtleburtle.net/bob/hash/doobs.html, function hashlittle().
+ *
+ * This hash is designed to provide a good overall performance in all platforms,
+ * including 32 bits. If you target only 64 bits, you can use faster hashes,
+ * like SpookyHash or FarmHash.
+ *
+ * \param init_val Initialization value.
+ * Using a different initialization value, you can generate a completely different set of hash values.
+ * Use 0 if not relevant.
+ * \param void_key Pointer to the data to hash.
+ * \param key_len Size of the data to hash.
+ * \note
+ * This function is endianess independent.
+ * \return The hash value of 32 bits.
+ */
+tommy_uint32_t tommy_hash_u32(tommy_uint32_t init_val, const void* void_key, tommy_size_t key_len);
+
+/**
+ * Hash function with a 64 bits result.
+ * Implementation of the Robert Jenkins "lookup3" hash 64 bits versions,
+ * from http://www.burtleburtle.net/bob/hash/doobs.html, function hashlittle2().
+ *
+ * This hash is designed to provide a good overall performance in all platforms,
+ * including 32 bits. If you target only 64 bits, you can use faster hashes,
+ * like SpookyHash or FarmHash.
+ *
+ * \param init_val Initialization value.
+ * Using a different initialization value, you can generate a completely different set of hash values.
+ * Use 0 if not relevant.
+ * \param void_key Pointer to the data to hash.
+ * \param key_len Size of the data to hash.
+ * \note
+ * This function is endianess independent.
+ * \return The hash value of 64 bits.
+ */
+tommy_uint64_t tommy_hash_u64(tommy_uint64_t init_val, const void* void_key, tommy_size_t key_len);
+
+/**
+ * String hash function with a 32 bits result.
+ * Implementation is based on the the Robert Jenkins "lookup3" hash 32 bits version,
+ * from http://www.burtleburtle.net/bob/hash/doobs.html, function hashlittle().
+ *
+ * This hash is designed to handle strings with an unknown length. If you
+ * know the string length, the other hash functions are surely faster.
+ *
+ * \param init_val Initialization value.
+ * Using a different initialization value, you can generate a completely different set of hash values.
+ * Use 0 if not relevant.
+ * \param void_key Pointer to the string to hash. It has to be 0 terminated.
+ * \note
+ * This function is endianess independent.
+ * \return The hash value of 32 bits.
+ */
+tommy_uint32_t tommy_strhash_u32(tommy_uint64_t init_val, const void* void_key);
+
+/**
+ * Integer reversible hash function for 32 bits.
+ * Implementation of the Robert Jenkins "4-byte Integer Hashing",
+ * from http://burtleburtle.net/bob/hash/integer.html
+ */
+tommy_inline tommy_uint32_t tommy_inthash_u32(tommy_uint32_t key)
+{
+ key -= key << 6;
+ key ^= key >> 17;
+ key -= key << 9;
+ key ^= key << 4;
+ key -= key << 3;
+ key ^= key << 10;
+ key ^= key >> 15;
+
+ return key;
+}
+
+/**
+ * Integer reversible hash function for 64 bits.
+ * Implementation of the Thomas Wang "Integer Hash Function",
+ * from http://web.archive.org/web/20071223173210/http://www.concentric.net/~Ttwang/tech/inthash.htm
+ */
+tommy_inline tommy_uint64_t tommy_inthash_u64(tommy_uint64_t key)
+{
+ key = ~key + (key << 21);
+ key = key ^ (key >> 24);
+ key = key + (key << 3) + (key << 8);
+ key = key ^ (key >> 14);
+ key = key + (key << 2) + (key << 4);
+ key = key ^ (key >> 28);
+ key = key + (key << 31);
+
+ return key;
+}
+
+#endif
+