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 TEST_ACM_RANDOM_H_ 12 #define TEST_ACM_RANDOM_H_ 13 14 #include "third_party/googletest/src/include/gtest/gtest.h" 15 16 #include "vpx/vpx_integer.h" 17 18 namespace libvpx_test { 19 20 class ACMRandom { 21 public: 22 ACMRandom() : random_(DeterministicSeed()) {} 23 24 explicit ACMRandom(int seed) : random_(seed) {} 25 26 void Reset(int seed) { 27 random_.Reseed(seed); 28 } 29 uint16_t Rand16(void) { 30 const uint32_t value = 31 random_.Generate(testing::internal::Random::kMaxRange); 32 return (value >> 16) & 0xffff; 33 } 34 35 uint8_t Rand8(void) { 36 const uint32_t value = 37 random_.Generate(testing::internal::Random::kMaxRange); 38 // There's a bit more entropy in the upper bits of this implementation. 39 return (value >> 24) & 0xff; 40 } 41 42 uint8_t Rand8Extremes(void) { 43 // Returns a random value near 0 or near 255, to better exercise 44 // saturation behavior. 45 const uint8_t r = Rand8(); 46 return r < 128 ? r << 4 : r >> 4; 47 } 48 49 int PseudoUniform(int range) { 50 return random_.Generate(range); 51 } 52 53 int operator()(int n) { 54 return PseudoUniform(n); 55 } 56 57 static int DeterministicSeed(void) { 58 return 0xbaba; 59 } 60 61 private: 62 testing::internal::Random random_; 63 }; 64 65 } // namespace libvpx_test 66 67 #endif // TEST_ACM_RANDOM_H_ 68
