| /* |
| * Copyright (c) 2021, Alliance for Open Media. All rights reserved |
| * |
| * This source code is subject to the terms of the BSD 3-Clause Clear License |
| * and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear |
| * License was not distributed with this source code in the LICENSE file, you |
| * can obtain it at aomedia.org/license/software-license/bsd-3-c-c/. 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 |
| * aomedia.org/license/patent-license/. |
| */ |
| |
| #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(void) { |
| return random_.Generate(testing::internal::Random::kMaxRange); |
| } |
| |
| uint16_t Rand16(void) { |
| const uint32_t value = |
| random_.Generate(testing::internal::Random::kMaxRange); |
| return (value >> 15) & 0xffff; |
| } |
| |
| int16_t Rand15Signed(void) { |
| const uint32_t value = |
| random_.Generate(testing::internal::Random::kMaxRange); |
| return (value >> 17) & 0xffff; |
| } |
| |
| uint16_t Rand12(void) { |
| 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; |
| } |
| |
| int16_t Rand9Signed(void) { |
| // Use 9 bits: values between 255 (0x0FF) and -256 (0x100). |
| const uint32_t value = random_.Generate(512); |
| return static_cast<int16_t>(value) - 256; |
| } |
| |
| uint8_t Rand8(void) { |
| 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(void) { |
| // 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(void) { return 0xbaba; } |
| |
| private: |
| testing::internal::Random random_; |
| }; |
| |
| } // namespace libaom_test |
| |
| #endif // AOM_TEST_ACM_RANDOM_H_ |