| // Copyright 2020 The Chromium Authors |
| // 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 <stddef.h> |
| #include <stdint.h> |
| |
| #include <vector> |
| |
| #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<int> buffer_; |
| }; |
| |
| } // namespace base |
| |
| #endif // BASE_POWER_MONITOR_MOVING_AVERAGE_H_ |