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/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
#ifndef AOM_TEST_ACM_RANDOM_H_
#define AOM_TEST_ACM_RANDOM_H_
#include "third_party/googletest/src/googletest/include/gtest/gtest.h"
#include "aom/aom_integer.h"
namespace libaom_test {
class ACMRandom {
public:
ACMRandom() : random_(DeterministicSeed()) {}
explicit ACMRandom(int seed) : random_(seed) {}
void Reset(int seed) { random_.Reseed(seed); }
// Generates a random 31-bit unsigned integer from [0, 2^31).
uint32_t Rand31() {
return random_.Generate(testing::internal::Random::kMaxRange);
}
uint16_t Rand16() {
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 >> 15) & 0xffff;
}
int16_t Rand16Signed() { return static_cast<int16_t>(Rand16()); }
int16_t Rand15() {
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 >> 16) & 0x7fff;
}
int16_t Rand15Signed() {
// Use 15 bits: values between 16383 (0x3FFF) and -16384 (0xC000).
return static_cast<int16_t>(Rand15()) - (1 << 14);
}
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);
}
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 libaom_test
#endif // AOM_TEST_ACM_RANDOM_H_
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