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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.
// RunningAverage defined in this file is used to generate statistics for
// bandwidth, latency and other performance metrics for remoting. Usually
// this data comes in as a stream and fluctuates a lot. They are processed by
// this class to generate a more stable value by taking average within a
// window of data points.
// All classes defined are thread-safe.
#ifndef REMOTING_BASE_RUNNING_AVERAGE_H_
#define REMOTING_BASE_RUNNING_AVERAGE_H_
#include <deque>
#include "base/basictypes.h"
#include "base/synchronization/lock.h"
#include "base/time.h"
namespace remoting {
class RunningAverage {
public:
// Construct a running average counter for a specific window size. The
// |windows_size| most recent values are kept and the average is reported.
RunningAverage(int window_size);
virtual ~RunningAverage();
// Record the provided data point.
void Record(int64 value);
// Return the average of data points in the last window.
double Average();
private:
// Size of the window. This is of type size_t to avoid casting when comparing
// with the size of |data_points_|.
size_t window_size_;
// Protects |data_points_| and |sum_|.
base::Lock lock_;
// Keep the values of all the data points.
std::deque<int64> data_points_;
// Sum of values in |data_points_|.
int64 sum_;
DISALLOW_COPY_AND_ASSIGN(RunningAverage);
};
} // namespace remoting
#endif // REMOTING_BASE_RUNNING_AVERAGE_H_
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