blob: 0e2e040e888920a229a0eb2a714ab591abd1aeaf [file] [log] [blame]
/*
* Copyright 2015 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_BASE_RATETRACKER_H_
#define WEBRTC_BASE_RATETRACKER_H_
#include <stdlib.h>
#include "webrtc/base/basictypes.h"
namespace rtc {
// Computes units per second over a given interval by tracking the units over
// each bucket of a given size and calculating the instantaneous rate assuming
// that over each bucket the rate was constant.
class RateTracker {
public:
RateTracker(uint32 bucket_milliseconds, size_t bucket_count);
virtual ~RateTracker();
// Computes the average rate over the most recent interval_milliseconds,
// or if the first sample was added within this period, computes the rate
// since the first sample was added.
double ComputeRateForInterval(uint32 interval_milliseconds) const;
// Computes the average rate over the rate tracker's recording interval
// of bucket_milliseconds * bucket_count.
double ComputeRate() const {
return ComputeRateForInterval(
bucket_milliseconds_ * static_cast<uint32>(bucket_count_));
}
// Computes the average rate since the first sample was added to the
// rate tracker.
double ComputeTotalRate() const;
// The total number of samples added.
size_t TotalSampleCount() const;
// Reads the current time in order to determine the appropriate bucket for
// these samples, and increments the count for that bucket by sample_count.
void AddSamples(size_t sample_count);
protected:
// overrideable for tests
virtual uint32 Time() const;
private:
void EnsureInitialized();
size_t NextBucketIndex(size_t bucket_index) const;
const uint32 bucket_milliseconds_;
const size_t bucket_count_;
size_t* sample_buckets_;
size_t total_sample_count_;
size_t current_bucket_;
uint32 bucket_start_time_milliseconds_;
uint32 initialization_time_milliseconds_;
};
} // namespace rtc
#endif // WEBRTC_BASE_RATETRACKER_H_