1 /*
2  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_RATE_STATISTICS_H_
12 #define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_RATE_STATISTICS_H_
13 
14 #include "webrtc/base/scoped_ptr.h"
15 #include "webrtc/typedefs.h"
16 
17 namespace webrtc {
18 
19 class RateStatistics {
20  public:
21   // window_size = window size in ms for the rate estimation
22   // scale = coefficient to convert counts/ms to desired units,
23   //         ex: if counts represents bytes, use 8*1000 to go to bits/s
24   RateStatistics(uint32_t window_size_ms, float scale);
25   ~RateStatistics();
26 
27   void Reset();
28   void Update(size_t count, int64_t now_ms);
29   uint32_t Rate(int64_t now_ms);
30 
31  private:
32   void EraseOld(int64_t now_ms);
33 
34   // Counters are kept in buckets (circular buffer), with one bucket
35   // per millisecond.
36   const int num_buckets_;
37   rtc::scoped_ptr<size_t[]> buckets_;
38 
39   // Total count recorded in buckets.
40   size_t accumulated_count_;
41 
42   // Oldest time recorded in buckets.
43   int64_t oldest_time_;
44 
45   // Bucket index of oldest counter recorded in buckets.
46   int oldest_index_;
47 
48   // To convert counts/ms to desired units
49   const float scale_;
50 };
51 }  // namespace webrtc
52 
53 #endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_RATE_STATISTICS_H_
54