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- // 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_BASE_MOVING_AVERAGE_H_
- #define MEDIA_BASE_MOVING_AVERAGE_H_
- #include <stddef.h>
- #include <stdint.h>
- #include <utility>
- #include <vector>
- #include "base/time/time.h"
- #include "media/base/media_export.h"
- #include "media/base/timestamp_constants.h"
- namespace media {
- // Simple class for calculating a moving average of fixed size.
- class MEDIA_EXPORT MovingAverage {
- public:
- // Creates a MovingAverage instance with space for |depth| samples.
- explicit MovingAverage(size_t depth);
- MovingAverage(const MovingAverage&) = delete;
- MovingAverage& operator=(const MovingAverage&) = delete;
- ~MovingAverage();
- // Adds a new sample to the average; replaces the oldest sample if |depth_|
- // has been exceeded. Updates |total_| to the new sum of values.
- void AddSample(base::TimeDelta sample);
- // Returns the current average of all held samples.
- base::TimeDelta Average() const;
- // Returns the population standard deviation of all held samples.
- base::TimeDelta Deviation() const;
- // Resets the state of the class to its initial post-construction state.
- void Reset();
- uint64_t count() const { return count_; }
- base::TimeDelta max() const { return max_; }
- size_t depth() const { return depth_; }
- // |first| is min, |second| is max of all samples in the window.
- std::pair<base::TimeDelta, base::TimeDelta> GetMinAndMax();
- private:
- // Maximum number of elements allowed in the average.
- const size_t depth_;
- std::vector<base::TimeDelta> samples_;
- // Number of elements seen thus far.
- uint64_t count_ = 0;
- base::TimeDelta total_;
- // Maximum value ever seen.
- base::TimeDelta max_ = kNoTimestamp;
- };
- } // namespace media
- #endif // MEDIA_BASE_MOVING_AVERAGE_H_
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