blender/intern/cycles/util/util_hash.h

/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __UTIL_HASH_H__
#define __UTIL_HASH_H__

#include "util/util_types.h"

CCL_NAMESPACE_BEGIN

ccl_device_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
}

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

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

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

  return i;
}
#endif

ccl_device_inline float hash_int_01(uint k)
{
  return (float)hash_int(k) * (1.0f / (float)0xFFFFFFFF);
}

CCL_NAMESPACE_END

#endif /* __UTIL_HASH_H__ */