1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef REMOTING_BASE_RUNNING_AVERAGE_H_ 6 #define REMOTING_BASE_RUNNING_AVERAGE_H_ 7 8 #include <deque> 9 10 #include "base/basictypes.h" 11 #include "base/synchronization/lock.h" 12 13 namespace remoting { 14 15 // Calculates the average of the most recent N recorded samples. 16 // This is typically used to smooth out random variation in point samples 17 // over bandwidth, frame rate, etc. 18 class RunningAverage { 19 public: 20 // Constructs a helper to average over the |window_size| most recent samples. 21 explicit RunningAverage(int window_size); 22 virtual ~RunningAverage(); 23 24 // Records a point sample. 25 void Record(int64 value); 26 27 // Returns the average over up to |window_size| of the most recent samples. 28 double Average(); 29 30 private: 31 // Stores the desired window size, as size_t to avoid casting when comparing 32 // with the size of |data_points_|. 33 const size_t window_size_; 34 35 // Protects |data_points_| and |sum_|. 36 base::Lock lock_; 37 38 // Stores the |window_size| most recently recorded samples. 39 std::deque<int64> data_points_; 40 41 // Holds the sum of the samples in |data_points_|. 42 int64 sum_; 43 44 DISALLOW_COPY_AND_ASSIGN(RunningAverage); 45 }; 46 47 } // namespace remoting 48 49 #endif // REMOTING_BASE_RUNNING_AVERAGE_H_ 50