text: /*
   *  Copyright (c) 2013 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 WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_RATE_STATISTICS_H_
  #define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_RATE_STATISTICS_H_
  
  #include "webrtc/system_wrappers/interface/scoped_ptr.h"
  #include "webrtc/typedefs.h"
  
  namespace webrtc {
  
  class RateStatistics {
   public:
    // window_size = window size in ms for the rate estimation
    // scale = coefficient to convert counts/ms to desired units,
    //         ex: if counts represents bytes, use 8*1000 to go to bits/s
    RateStatistics(uint32_t window_size_ms, float scale);
    ~RateStatistics();
  
    void Reset();
    void Update(size_t count, int64_t now_ms);
    uint32_t Rate(int64_t now_ms);
  
   private:
    void EraseOld(int64_t now_ms);
  
    // Counters are kept in buckets (circular buffer), with one bucket
    // per millisecond.
    const int num_buckets_;
    scoped_ptr<size_t[]> buckets_;
  
    // Total count recorded in buckets.
    size_t accumulated_count_;
  
    // Oldest time recorded in buckets.
    int64_t oldest_time_;
  
    // Bucket index of oldest counter recorded in buckets.
    int oldest_index_;
  
    // To convert counts/ms to desired units
    const float scale_;
  };
  }  // namespace webrtc
  
  #endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_RATE_STATISTICS_H_
  