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Diffstat (limited to 'chromium/media/base/test_random.h')
-rw-r--r-- | chromium/media/base/test_random.h | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/chromium/media/base/test_random.h b/chromium/media/base/test_random.h new file mode 100644 index 00000000000..ba081cb57a0 --- /dev/null +++ b/chromium/media/base/test_random.h @@ -0,0 +1,45 @@ +// Copyright 2015 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#ifndef MEDIA_BLINK_TEST_RANDOM_H_ +#define MEDIA_BLINK_TEST_RANDOM_H_ + +#include <stdint.h> + +#include "base/logging.h" + +// Vastly simplified ACM random class meant to only be used for testing. +// This class is meant to generate predictable sequences of pseudorandom +// numbers, unlike the classes in base/rand_util.h which are meant to generate +// unpredictable sequences. +// See +// https://code.google.com/p/szl/source/browse/trunk/src/utilities/acmrandom.h +// for more information. + +namespace media { + +class TestRandom { + public: + explicit TestRandom(uint32_t seed) { + seed_ = seed & 0x7fffffff; // make this a non-negative number + if (seed_ == 0 || seed_ == M) { + seed_ = 1; + } + } + + int32_t Rand() { + static const uint64_t A = 16807; // bits 14, 8, 7, 5, 2, 1, 0 + seed_ = static_cast<int32_t>((seed_ * A) % M); + CHECK_GT(seed_, 0); + return seed_; + } + + private: + static const uint64_t M = 2147483647L; // 2^32-1 + int32_t seed_; +}; + +} // namespace media + +#endif // MEDIA_BLINK_TEST_RANDOM_H_ |