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* 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.
#include <stdint.h>
#include <stdlib.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 {
RateTracker(int64_t 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(int64_t 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_ *
// Computes the average rate since the first sample was added to the
// rate tracker.
double ComputeTotalRate() const;
// The total number of samples added.
int64_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(int64_t sample_count);
// Increment count for bucket at `current_time_ms`.
void AddSamplesAtTime(int64_t current_time_ms, int64_t sample_count);
// overrideable for tests
virtual int64_t Time() const;
void EnsureInitialized();
size_t NextBucketIndex(size_t bucket_index) const;
const int64_t bucket_milliseconds_;
const size_t bucket_count_;
int64_t* sample_buckets_;
size_t total_sample_count_;
size_t current_bucket_;
int64_t bucket_start_time_milliseconds_;
int64_t initialization_time_milliseconds_;
} // namespace rtc