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Diffstat (limited to 'media/libvpx/libvpx/test/acm_random.h')
-rw-r--r-- | media/libvpx/libvpx/test/acm_random.h | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/media/libvpx/libvpx/test/acm_random.h b/media/libvpx/libvpx/test/acm_random.h new file mode 100644 index 0000000000..e3520c47de --- /dev/null +++ b/media/libvpx/libvpx/test/acm_random.h @@ -0,0 +1,88 @@ +/* + * Copyright (c) 2012 The WebM project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#ifndef VPX_TEST_ACM_RANDOM_H_ +#define VPX_TEST_ACM_RANDOM_H_ + +#include <assert.h> + +#include <limits> + +#include "third_party/googletest/src/include/gtest/gtest.h" + +#include "vpx/vpx_integer.h" + +namespace libvpx_test { + +class ACMRandom { + public: + ACMRandom() : random_(DeterministicSeed()) {} + + explicit ACMRandom(int seed) : random_(seed) {} + + void Reset(int seed) { random_.Reseed(seed); } + uint16_t Rand16() { + const uint32_t value = + random_.Generate(testing::internal::Random::kMaxRange); + return (value >> 15) & 0xffff; + } + + int32_t Rand20Signed() { + // Use 20 bits: values between 524287 and -524288. + const uint32_t value = random_.Generate(1048576); + return static_cast<int32_t>(value) - 524288; + } + + int16_t Rand16Signed() { + // Use 16 bits: values between 32767 and -32768. + return static_cast<int16_t>(random_.Generate(65536)); + } + + 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); + } + + uint32_t RandRange(const uint32_t range) { + // testing::internal::Random::Generate provides values in the range + // testing::internal::Random::kMaxRange. + assert(range <= testing::internal::Random::kMaxRange); + return random_.Generate(range); + } + + 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 libvpx_test + +#endif // VPX_TEST_ACM_RANDOM_H_ |