// 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.
#ifndef REMOTING_BASE_RUNNING_AVERAGE_H_
#define REMOTING_BASE_RUNNING_AVERAGE_H_
#include <deque>
#include "base/basictypes.h"
#include "base/synchronization/lock.h"
namespace remoting {
// Calculates the average of the most recent N recorded samples.
// This is typically used to smooth out random variation in point samples
// over bandwidth, frame rate, etc.
class RunningAverage {
public:
// Constructs a helper to average over the |window_size| most recent samples.
explicit RunningAverage(int window_size);
virtual ~RunningAverage();
// Records a point sample.
void Record(int64 value);
// Returns the average over up to |window_size| of the most recent samples.
double Average();
private:
// Stores the desired window size, as size_t to avoid casting when comparing
// with the size of |data_points_|.
const size_t window_size_;
// Protects |data_points_| and |sum_|.
base::Lock lock_;
// Stores the |window_size| most recently recorded samples.
std::deque<int64> data_points_;
// Holds the sum of the samples in |data_points_|.
int64 sum_;
DISALLOW_COPY_AND_ASSIGN(RunningAverage);
};
} // namespace remoting
#endif // REMOTING_BASE_RUNNING_AVERAGE_H_