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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_BASE_ROLLING_TIME_DELTA_HISTORY_H_
#define CC_BASE_ROLLING_TIME_DELTA_HISTORY_H_
#include <stddef.h>
#include <set>
#include "base/containers/circular_deque.h"
#include "base/containers/flat_map.h"
#include "base/time/time.h"
#include "cc/base/base_export.h"
namespace cc {
// Stores a limited number of samples. When the maximum size is reached, each
// insertion results in the deletion of the oldest remaining sample.
class CC_BASE_EXPORT RollingTimeDeltaHistory {
public:
explicit RollingTimeDeltaHistory(size_t max_size);
RollingTimeDeltaHistory(const RollingTimeDeltaHistory&) = delete;
~RollingTimeDeltaHistory();
RollingTimeDeltaHistory& operator=(const RollingTimeDeltaHistory&) = delete;
void InsertSample(base::TimeDelta time);
void RemoveOldestSample();
size_t sample_count() const { return sample_set_.size(); }
void Clear();
// Returns the smallest sample that is greater than or equal to the specified
// percent of samples. If there aren't any samples, returns base::TimeDelta().
base::TimeDelta Percentile(double percent) const;
private:
typedef std::multiset<base::TimeDelta> TimeDeltaMultiset;
base::TimeDelta ComputePercentile(double percent) const;
TimeDeltaMultiset sample_set_;
base::circular_deque<TimeDeltaMultiset::iterator> chronological_sample_deque_;
size_t max_size_;
mutable base::flat_map<double, base::TimeDelta> percentile_cache_;
};
} // namespace cc
#endif // CC_BASE_ROLLING_TIME_DELTA_HISTORY_H_
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