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// Copyright (c) 2011 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.
#include <stdint.h>
#include <utility>
#include "base/containers/queue.h"
#include "base/macros.h"
#include "base/sequence_checker.h"
#include "base/time/default_tick_clock.h"
#include "base/time/tick_clock.h"
#include "base/time/time.h"
namespace remoting {
// Measures average rate per second of a sequence of point rate samples
// over a specified time window. This can be used to measure bandwidth, frame
// rates, etc.
class RateCounter {
// Constructs a rate counter over the specified |time_window|.
explicit RateCounter(base::TimeDelta time_window);
virtual ~RateCounter();
// Records a point event count to include in the rate.
void Record(int64_t value);
// Returns the rate-per-second of values recorded over the time window.
// Note that rates reported before |time_window| has elapsed are not accurate.
double Rate() const;
void set_tick_clock_for_tests(const base::TickClock* tick_clock) {
tick_clock_ = tick_clock;
// Type used to store data points with timestamps.
typedef std::pair<base::TimeTicks, int64_t> DataPoint;
// Removes data points more than |time_window| older than |current_time|.
void EvictOldDataPoints(base::TimeTicks current_time);
// Time window over which to calculate the rate.
const base::TimeDelta time_window_;
// Queue containing data points in the order in which they were recorded.
base::queue<DataPoint> data_points_;
// Sum of values in |data_points_|.
int64_t sum_;
const base::TickClock* tick_clock_ = base::DefaultTickClock::GetInstance();
} // namespace remoting