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-rw-r--r-- | third_party/aom/test/acm_random.h | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/third_party/aom/test/acm_random.h b/third_party/aom/test/acm_random.h new file mode 100644 index 0000000000..15e8c9cc2e --- /dev/null +++ b/third_party/aom/test/acm_random.h @@ -0,0 +1,88 @@ +/* + * 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_ |