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/*
* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_NUMERICS_MOVING_AVERAGE_H_
#define RTC_BASE_NUMERICS_MOVING_AVERAGE_H_
#include <stddef.h>
#include <stdint.h>
#include <vector>
#include "absl/types/optional.h"
namespace rtc {
// Calculates average over fixed size window. If there are less than window
// size elements, calculates average of all inserted so far elements.
//
class MovingAverage {
public:
// Maximum supported window size is 2^32 - 1.
explicit MovingAverage(size_t window_size);
~MovingAverage();
// MovingAverage is neither copyable nor movable.
MovingAverage(const MovingAverage&) = delete;
MovingAverage& operator=(const MovingAverage&) = delete;
// Adds new sample. If the window is full, the oldest element is pushed out.
void AddSample(int sample);
// Returns rounded down average of last `window_size` elements or all
// elements if there are not enough of them. Returns nullopt if there were
// no elements added.
absl::optional<int> GetAverageRoundedDown() const;
// Same as above but rounded to the closest integer.
absl::optional<int> GetAverageRoundedToClosest() const;
// Returns unrounded average over the window.
absl::optional<double> GetUnroundedAverage() const;
// Resets to the initial state before any elements were added.
void Reset();
// Returns number of elements in the window.
size_t Size() const;
private:
// Total number of samples added to the class since last reset.
size_t count_ = 0;
// Sum of the samples in the moving window.
int64_t sum_ = 0;
// Circular buffer for all the samples in the moving window.
// Size is always `window_size`
std::vector<int> history_;
};
} // namespace rtc
#endif // RTC_BASE_NUMERICS_MOVING_AVERAGE_H_
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