1 /* 2 * Copyright (c) 2012 The WebM project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef LIBGAV1_TESTS_THIRD_PARTY_LIBVPX_ACM_RANDOM_H_ 12 #define LIBGAV1_TESTS_THIRD_PARTY_LIBVPX_ACM_RANDOM_H_ 13 14 #include <cassert> 15 #include <cstdint> 16 #include <limits> 17 18 #include "gtest/gtest.h" 19 20 namespace libvpx_test { 21 22 class ACMRandom { 23 public: ACMRandom()24 ACMRandom() : random_(DeterministicSeed()) {} 25 ACMRandom(int seed)26 explicit ACMRandom(int seed) : random_(seed) {} 27 Reset(int seed)28 void Reset(int seed) { random_.Reseed(seed); } Rand16(void)29 uint16_t Rand16(void) { 30 const uint32_t value = 31 random_.Generate(testing::internal::Random::kMaxRange); 32 return (value >> 15) & 0xffff; 33 } 34 Rand20Signed(void)35 int32_t Rand20Signed(void) { 36 // Use 20 bits: values between 524287 and -524288. 37 const uint32_t value = random_.Generate(1048576); 38 return static_cast<int32_t>(value) - 524288; 39 } 40 Rand16Signed(void)41 int16_t Rand16Signed(void) { 42 // Use 16 bits: values between 32767 and -32768. 43 return static_cast<int16_t>(random_.Generate(65536)); 44 } 45 Rand13Signed(void)46 int16_t Rand13Signed(void) { 47 // Use 13 bits: values between 4095 and -4096. 48 const uint32_t value = random_.Generate(8192); 49 return static_cast<int16_t>(value) - 4096; 50 } 51 Rand9Signed(void)52 int16_t Rand9Signed(void) { 53 // Use 9 bits: values between 255 (0x0FF) and -256 (0x100). 54 const uint32_t value = random_.Generate(512); 55 return static_cast<int16_t>(value) - 256; 56 } 57 Rand8(void)58 uint8_t Rand8(void) { 59 const uint32_t value = 60 random_.Generate(testing::internal::Random::kMaxRange); 61 // There's a bit more entropy in the upper bits of this implementation. 62 return (value >> 23) & 0xff; 63 } 64 Rand8Extremes(void)65 uint8_t Rand8Extremes(void) { 66 // Returns a random value near 0 or near 255, to better exercise 67 // saturation behavior. 68 const uint8_t r = Rand8(); 69 return static_cast<uint8_t>((r < 128) ? r << 4 : r >> 4); 70 } 71 RandRange(const uint32_t range)72 uint32_t RandRange(const uint32_t range) { 73 // testing::internal::Random::Generate provides values in the range 74 // testing::internal::Random::kMaxRange. 75 assert(range <= testing::internal::Random::kMaxRange); 76 return random_.Generate(range); 77 } 78 PseudoUniform(int range)79 int PseudoUniform(int range) { return random_.Generate(range); } 80 operator()81 int operator()(int n) { return PseudoUniform(n); } 82 DeterministicSeed(void)83 static constexpr int DeterministicSeed(void) { return 0xbaba; } 84 85 private: 86 testing::internal::Random random_; 87 }; 88 89 } // namespace libvpx_test 90 91 #endif // LIBGAV1_TESTS_THIRD_PARTY_LIBVPX_ACM_RANDOM_H_ 92