2 * Copyright (c) 2012 The WebM project authors. All Rights Reserved.
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.
11 #ifndef TEST_ACM_RANDOM_H_
12 #define TEST_ACM_RANDOM_H_
14 #include "third_party/googletest/src/include/gtest/gtest.h"
16 #include "vpx/vpx_integer.h"
18 namespace libvpx_test {
22 ACMRandom() : random_(DeterministicSeed()) {}
24 explicit ACMRandom(int seed) : random_(seed) {}
26 void Reset(int seed) { random_.Reseed(seed); }
27 uint16_t Rand16(void) {
28 const uint32_t value =
29 random_.Generate(testing::internal::Random::kMaxRange);
30 return (value >> 15) & 0xffff;
33 int16_t Rand9Signed(void) {
34 // Use 9 bits: values between 255 (0x0FF) and -256 (0x100).
35 const uint32_t value = random_.Generate(512);
36 return static_cast<int16_t>(value) - 256;
40 const uint32_t value =
41 random_.Generate(testing::internal::Random::kMaxRange);
42 // There's a bit more entropy in the upper bits of this implementation.
43 return (value >> 23) & 0xff;
46 uint8_t Rand8Extremes(void) {
47 // Returns a random value near 0 or near 255, to better exercise
48 // saturation behavior.
49 const uint8_t r = Rand8();
50 return r < 128 ? r << 4 : r >> 4;
53 int PseudoUniform(int range) { return random_.Generate(range); }
55 int operator()(int n) { return PseudoUniform(n); }
57 static int DeterministicSeed(void) { return 0xbaba; }
60 testing::internal::Random random_;
63 } // namespace libvpx_test
65 #endif // TEST_ACM_RANDOM_H_