1 /* 2 * Copyright 2015 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_BASE_RATETRACKER_H_ 12 #define WEBRTC_BASE_RATETRACKER_H_ 13 14 #include <stdlib.h> 15 #include "webrtc/base/basictypes.h" 16 17 namespace rtc { 18 19 // Computes units per second over a given interval by tracking the units over 20 // each bucket of a given size and calculating the instantaneous rate assuming 21 // that over each bucket the rate was constant. 22 class RateTracker { 23 public: 24 RateTracker(uint32_t bucket_milliseconds, size_t bucket_count); 25 virtual ~RateTracker(); 26 27 // Computes the average rate over the most recent interval_milliseconds, 28 // or if the first sample was added within this period, computes the rate 29 // since the first sample was added. 30 double ComputeRateForInterval(uint32_t interval_milliseconds) const; 31 32 // Computes the average rate over the rate tracker's recording interval 33 // of bucket_milliseconds * bucket_count. 34 double ComputeRate() const { 35 return ComputeRateForInterval(bucket_milliseconds_ * 36 static_cast<uint32_t>(bucket_count_)); 37 } 38 39 // Computes the average rate since the first sample was added to the 40 // rate tracker. 41 double ComputeTotalRate() const; 42 43 // The total number of samples added. 44 size_t TotalSampleCount() const; 45 46 // Reads the current time in order to determine the appropriate bucket for 47 // these samples, and increments the count for that bucket by sample_count. 48 void AddSamples(size_t sample_count); 49 50 protected: 51 // overrideable for tests 52 virtual uint32_t Time() const; 53 54 private: 55 void EnsureInitialized(); 56 size_t NextBucketIndex(size_t bucket_index) const; 57 58 const uint32_t bucket_milliseconds_; 59 const size_t bucket_count_; 60 size_t* sample_buckets_; 61 size_t total_sample_count_; 62 size_t current_bucket_; 63 uint32_t bucket_start_time_milliseconds_; 64 uint32_t initialization_time_milliseconds_; 65 }; 66 67 } // namespace rtc 68 69 #endif // WEBRTC_BASE_RATETRACKER_H_ 70
