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/*
* Copyright (c) 2023 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_FREQUENCY_TRACKER_H_
#define RTC_BASE_FREQUENCY_TRACKER_H_
#include <stddef.h>
#include <stdint.h>
#include <optional>
#include "api/units/frequency.h"
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "rtc_base/rate_statistics.h"
#include "rtc_base/system/rtc_export.h"
namespace webrtc {
// Class to estimate frequency (e.g. frame rate) over running window.
// Timestamps used in Update() and Rate() must never decrease for two
// consecutive calls.
// This class is thread unsafe.
class RTC_EXPORT FrequencyTracker {
public:
explicit FrequencyTracker(TimeDelta window_size);
FrequencyTracker(const FrequencyTracker&) = default;
FrequencyTracker(FrequencyTracker&&) = default;
FrequencyTracker& operator=(const FrequencyTracker&) = delete;
FrequencyTracker& operator=(FrequencyTracker&&) = delete;
~FrequencyTracker() = default;
// Reset instance to original state.
void Reset() { impl_.Reset(); }
// Update rate with a new data point, moving averaging window as needed.
void Update(int64_t count, Timestamp now);
void Update(Timestamp now) { Update(1, now); }
// Returns rate, moving averaging window as needed.
// Returns nullopt when rate can't be measured.
std::optional<Frequency> Rate(Timestamp now) const;
private:
RateStatistics impl_;
};
} // namespace webrtc
#endif // RTC_BASE_FREQUENCY_TRACKER_H_