blender/intern/cycles/util/util_hash.h

/*
 * 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__

#include "util_types.h"

CCL_NAMESPACE_BEGIN

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

	uint 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 uint hash_int(uint k)
{
	return hash_int_2d(k, 0);
}

static inline uint hash_string(const char *str)
{
	uint i = 0, c;

	while ((c = *str++))
		i = i * 37 + c;

	return i;
}

CCL_NAMESPACE_END

#endif /* __UTIL_HASH_H__ */