tommyhash.h

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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.
 */

#ifndef __TOMMYHASH_H
#define __TOMMYHASH_H

#include "tommytypes.h"

/******************************************************************************/
/* hash */

typedef tommy_key_t tommy_hash_t;

tommy_uint32_t tommy_hash_u32(tommy_uint32_t init_val, const void* void_key, tommy_size_t key_len);

tommy_uint64_t tommy_hash_u64(tommy_uint64_t init_val, const void* void_key, tommy_size_t key_len);

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;
}

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