// 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. #ifndef BASE_POWER_MONITOR_MOVING_AVERAGE_H_ #define BASE_POWER_MONITOR_MOVING_AVERAGE_H_ #include #include #include #include "base/base_export.h" namespace base { // Calculates average over a small fixed size window. If there are less than // window size elements, calculates average of all inserted elements so far. // This implementation support a maximum window size of 255. // Ported from third_party/webrtc/rtc_base/numerics/moving_average.h. class BASE_EXPORT MovingAverage { public: // Maximum supported window size is 2^8 - 1 = 255. explicit MovingAverage(uint8_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. int GetAverageRoundedDown() const; // Same as above but rounded to the closest integer. int GetAverageRoundedToClosest() const; // Returns unrounded average over the window. 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: // Stores `window_size` used in the constructor. uint8_t window_size_ = 0; // New samples are added at this index. Counts modulo `window_size`. uint8_t index_ = 0; // Set to true when the `buffer_` is full. i.e, all elements contain a // sample added by AddSample(). bool full_ = false; // 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 buffer_; }; } // namespace base #endif // BASE_POWER_MONITOR_MOVING_AVERAGE_H_