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// Copyright 2020 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.
#include "media/base/tuneable.h"
#include <random>
#include "base/cxx17_backports.h"
#include "base/hash/hash.h"
#include "base/metrics/field_trial_params.h"
#include "base/no_destructor.h"
#include "base/strings/string_number_conversions.h"
#include "media/base/media_switches.h"
namespace {
// Get the finch parameter `name`, and clamp it to the given values. Return
// `default_value` if there is no parameter, or if the experiment is off.
template <typename T>
T GetParam(const char* name,
T minimum_value,
T default_value,
T maximum_value) {
return static_cast<T>(GetParam<int>(name, static_cast<int>(minimum_value),
static_cast<int>(default_value),
static_cast<int>(maximum_value)));
}
template <>
int GetParam<int>(const char* name,
int minimum_value,
int default_value,
int maximum_value) {
return base::clamp(
base::FeatureParam<int>(&::media::kMediaOptimizer, name, default_value)
.Get(),
minimum_value, maximum_value);
}
template <>
base::TimeDelta GetParam<base::TimeDelta>(const char* name,
base::TimeDelta minimum_value,
base::TimeDelta default_value,
base::TimeDelta maximum_value) {
return base::Milliseconds(GetParam<int>(name, minimum_value.InMilliseconds(),
default_value.InMilliseconds(),
maximum_value.InMilliseconds()));
}
} // namespace
namespace media {
template <typename T>
Tuneable<T>::Tuneable(const char* name,
T minimum_value,
T default_value,
T maximum_value) {
// Fetch the finch-provided value, clamped to the min, max and defaulted to
// the hardcoded default if it's unset.
t_ = GetParam<T>(name, minimum_value, default_value, maximum_value);
}
template <typename T>
Tuneable<T>::~Tuneable() = default;
// All allowed Tuneable types. Be sure that GenerateRandom() and GetParam()
// do something sane for any type you add.
template class MEDIA_EXPORT Tuneable<int>;
template class MEDIA_EXPORT Tuneable<base::TimeDelta>;
template class MEDIA_EXPORT Tuneable<size_t>;
} // namespace media
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