libfirm/adt/hashptr.h

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/*
 * Copyright (C) 1995-2011 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

#ifndef FIRM_ADT_HASHPTR_H
#define FIRM_ADT_HASHPTR_H

#include <stdlib.h>
#include "../begin.h"

#define _FIRM_FNV_OFFSET_BASIS 2166136261U
#define _FIRM_FNV_FNV_PRIME 16777619U

/* Computing x * _FIRM_FNV_FNV_PRIME */
#define _FIRM_FNV_TIMES_PRIME(x) ((x) * _FIRM_FNV_FNV_PRIME)

static inline unsigned hash_data(const unsigned char *data, size_t bytes)
{
    size_t   i;
    unsigned hash = _FIRM_FNV_OFFSET_BASIS;

    for(i = 0; i < bytes; ++i) {
        hash = _FIRM_FNV_TIMES_PRIME(hash);
        hash ^= data[i];
    }

    return hash;
}

static inline unsigned hash_str(const char *str)
{
    unsigned i;
    unsigned hash = _FIRM_FNV_OFFSET_BASIS;

    for(i = 0; str[i] != '\0'; ++i) {
        hash = _FIRM_FNV_TIMES_PRIME(hash);
        hash ^= str[i];
    }

    return hash;
}

static inline unsigned hash_ptr(const void *ptr)
{
    return ((unsigned)(((char *) (ptr) - (char *)0) >> 3));
}

static inline unsigned hash_combine(unsigned x, unsigned y)
{
    unsigned hash = _FIRM_FNV_TIMES_PRIME(_FIRM_FNV_OFFSET_BASIS);
    hash ^= x;
    hash  = _FIRM_FNV_TIMES_PRIME(hash);
    hash ^= y;
    return hash;
}

#include "../end.h"

#endif