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/*
* Copyright (c) 2012 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef VPX_TEST_ACM_RANDOM_H_
#define VPX_TEST_ACM_RANDOM_H_
#include <assert.h>
#include <limits>
#include "gtest/gtest.h"
#include "vpx/vpx_integer.h"
namespace libvpx_test {
class ACMRandom {
public:
ACMRandom() : random_(DeterministicSeed()) {}
explicit ACMRandom(int seed) : random_(seed) {}
void Reset(int seed) { random_.Reseed(seed); }
uint16_t Rand16() {
const uint32_t value =
random_.Generate(testing::internal::Random::kMaxRange);
return (value >> 15) & 0xffff;
}
int32_t Rand20Signed() {
// Use 20 bits: values between 524287 and -524288.
const uint32_t value = random_.Generate(1048576);
return static_cast<int32_t>(value) - 524288;
}
int16_t Rand16Signed() {
// Use 16 bits: values between 32767 and -32768.
return static_cast<int16_t>(random_.Generate(65536));
}
uint16_t Rand12() {
const uint32_t value =
random_.Generate(testing::internal::Random::kMaxRange);
// There's a bit more entropy in the upper bits of this implementation.
return (value >> 19) & 0xfff;
}
uint8_t Rand8() {
const uint32_t value =
random_.Generate(testing::internal::Random::kMaxRange);
// There's a bit more entropy in the upper bits of this implementation.
return (value >> 23) & 0xff;
}
uint8_t Rand8Extremes() {
// Returns a random value near 0 or near 255, to better exercise
// saturation behavior.
const uint8_t r = Rand8();
return static_cast<uint8_t>((r < 128) ? r << 4 : r >> 4);
}
uint32_t RandRange(const uint32_t range) {
// testing::internal::Random::Generate provides values in the range
// testing::internal::Random::kMaxRange.
assert(range <= testing::internal::Random::kMaxRange);
return random_.Generate(range);
}
int PseudoUniform(int range) { return random_.Generate(range); }
int operator()(int n) { return PseudoUniform(n); }
static int DeterministicSeed() { return 0xbaba; }
private:
testing::internal::Random random_;
};
} // namespace libvpx_test
#endif // VPX_TEST_ACM_RANDOM_H_
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