66 lines
1.8 KiB
C++
66 lines
1.8 KiB
C++
/*
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* Copyright (c) 2012 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef TEST_ACM_RANDOM_H_
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#define TEST_ACM_RANDOM_H_
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#include "third_party/googletest/src/include/gtest/gtest.h"
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#include "vpx/vpx_integer.h"
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namespace libvpx_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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uint16_t Rand16(void) {
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const uint32_t value =
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random_.Generate(testing::internal::Random::kMaxRange);
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return (value >> 15) & 0xffff;
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}
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int16_t Rand9Signed(void) {
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// Use 9 bits: values between 255 (0x0FF) and -256 (0x100).
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const uint32_t value = random_.Generate(512);
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return static_cast<int16_t>(value) - 256;
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}
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uint8_t Rand8(void) {
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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(void) {
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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 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(void) { return 0xbaba; }
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private:
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testing::internal::Random random_;
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};
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} // namespace libvpx_test
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#endif // TEST_ACM_RANDOM_H_
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