88 lines
2.6 KiB
C++
88 lines
2.6 KiB
C++
/*
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* Copyright (c) 2016, Alliance for Open Media. All rights reserved.
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*
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* This source code is subject to the terms of the BSD 2 Clause License and
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* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
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* was not distributed with this source code in the LICENSE file, you can
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* obtain it at www.aomedia.org/license/software. If the Alliance for Open
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* Media Patent License 1.0 was not distributed with this source code in the
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* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
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*/
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#ifndef AOM_TEST_ACM_RANDOM_H_
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#define AOM_TEST_ACM_RANDOM_H_
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#include "gtest/gtest.h"
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#include "aom/aom_integer.h"
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namespace libaom_test {
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class ACMRandom {
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public:
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ACMRandom() : random_(DeterministicSeed()) {}
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explicit ACMRandom(int seed) : random_(seed) {}
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void Reset(int seed) { random_.Reseed(seed); }
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// Generates a random 31-bit unsigned integer from [0, 2^31).
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uint32_t Rand31() {
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return random_.Generate(testing::internal::Random::kMaxRange);
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}
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uint16_t Rand16() {
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const uint32_t value =
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random_.Generate(testing::internal::Random::kMaxRange);
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// There's a bit more entropy in the upper bits of this implementation.
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return (value >> 15) & 0xffff;
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}
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int16_t Rand16Signed() { return static_cast<int16_t>(Rand16()); }
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uint16_t Rand15() {
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const uint32_t value =
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random_.Generate(testing::internal::Random::kMaxRange);
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// There's a bit more entropy in the upper bits of this implementation.
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return (value >> 16) & 0x7fff;
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}
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int16_t Rand15Signed() {
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// Use 15 bits: values between 16383 (0x3FFF) and -16384 (0xC000).
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return static_cast<int16_t>(Rand15()) - (1 << 14);
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}
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uint16_t Rand12() {
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const uint32_t value =
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random_.Generate(testing::internal::Random::kMaxRange);
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// There's a bit more entropy in the upper bits of this implementation.
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return (value >> 19) & 0xfff;
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}
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uint8_t Rand8() {
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const uint32_t value =
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random_.Generate(testing::internal::Random::kMaxRange);
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// There's a bit more entropy in the upper bits of this implementation.
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return (value >> 23) & 0xff;
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}
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uint8_t Rand8Extremes() {
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// Returns a random value near 0 or near 255, to better exercise
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// saturation behavior.
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const uint8_t r = Rand8();
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return static_cast<uint8_t>((r < 128) ? r << 4 : r >> 4);
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}
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int PseudoUniform(int range) { return random_.Generate(range); }
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int operator()(int n) { return PseudoUniform(n); }
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static int DeterministicSeed() { return 0xbaba; }
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private:
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testing::internal::Random random_;
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};
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} // namespace libaom_test
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#endif // AOM_TEST_ACM_RANDOM_H_
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