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// Copyright 2018 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_LEARNING_IMPL_RANDOM_NUMBER_GENERATOR_H_
#define MEDIA_LEARNING_IMPL_RANDOM_NUMBER_GENERATOR_H_
#include <cstdint>
#include "base/component_export.h"
#include "base/memory/raw_ptr.h"
namespace media {
// Class to encapsulate a random number generator with an implementation for
// tests that provides repeatable, platform-independent sequences.
class COMPONENT_EXPORT(LEARNING_IMPL) RandomNumberGenerator {
public:
RandomNumberGenerator() = default;
RandomNumberGenerator(const RandomNumberGenerator&) = delete;
RandomNumberGenerator& operator=(const RandomNumberGenerator&) = delete;
virtual ~RandomNumberGenerator() = default;
// Return a random generator that will return unpredictable values in the
// //base/rand_util.h sense. See TestRandomGenerator if you'd like one that's
// more predictable for tests.
static RandomNumberGenerator* Default();
// Taken from rand_util.h
// Returns a random number in range [0, UINT64_MAX]. Thread-safe.
virtual uint64_t Generate() = 0;
// Returns a random number in range [0, range). Thread-safe.
uint64_t Generate(uint64_t range);
// Returns a floating point number in the range [0, range). Thread-safe.
// This isn't an overload of Generate() to be sure that one isn't surprised by
// the result.
double GenerateDouble(double range);
};
// Handy mix-in class if you want to support rng injection.
class COMPONENT_EXPORT(LEARNING_IMPL) HasRandomNumberGenerator {
public:
// If |rng| is null, then we'll create a new one as a convenience.
explicit HasRandomNumberGenerator(RandomNumberGenerator* rng = nullptr);
~HasRandomNumberGenerator();
void SetRandomNumberGeneratorForTesting(RandomNumberGenerator* rng);
protected:
RandomNumberGenerator* rng() const { return rng_; }
private:
raw_ptr<RandomNumberGenerator> rng_ = nullptr;
};
} // namespace media
#endif // MEDIA_LEARNING_IMPL_RANDOM_NUMBER_GENERATOR_H_
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