ref: 5cfaf561d9928261f3ff49d744239cc0dcf877b9
dir: /test/acm_random.h/
/* * 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(void) { const uint32_t value = random_.Generate(testing::internal::Random::kMaxRange); return (value >> 15) & 0xffff; } int32_t Rand20Signed(void) { // 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(void) { // Use 16 bits: values between 32767 and -32768. const uint32_t value = random_.Generate(65536); return static_cast<int16_t>(value) - 32768; } int16_t Rand13Signed(void) { // Use 13 bits: values between 4095 and -4096. const uint32_t value = random_.Generate(8192); return static_cast<int16_t>(value) - 4096; } 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 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(void) { return 0xbaba; } private: testing::internal::Random random_; }; } // namespace libvpx_test #endif // VPX_TEST_ACM_RANDOM_H_