util_hash.h

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/*
 * Copyright 2011, Blender Foundation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#ifndef __UTIL_HASH_H__
#define __UTIL_HASH_H__

CCL_NAMESPACE_BEGIN

static inline unsigned int hash_int_2d(unsigned int kx, unsigned int ky)
{
    #define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))

    unsigned int a, b, c;

    a = b = c = 0xdeadbeef + (2 << 2) + 13;
    a += kx;
    b += ky;

    c ^= b; c -= rot(b,14);
    a ^= c; a -= rot(c,11);
    b ^= a; b -= rot(a,25);
    c ^= b; c -= rot(b,16);
    a ^= c; a -= rot(c,4);
    b ^= a; b -= rot(a,14);
    c ^= b; c -= rot(b,24);

    return c;

    #undef rot
}

static inline unsigned int hash_int(unsigned int k)
{
    return hash_int_2d(k, 0);
}

CCL_NAMESPACE_END

#endif /* __UTIL_HASH_H__ */