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/*
* Copyright (c) 2018 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 API_NUMERICS_SAMPLES_STATS_COUNTER_H_
#define API_NUMERICS_SAMPLES_STATS_COUNTER_H_
#include <stddef.h>
#include <stdint.h>
#include <map>
#include <string>
#include <vector>
#include "api/array_view.h"
#include "api/units/timestamp.h"
#include "rtc_base/checks.h"
#include "rtc_base/numerics/running_statistics.h"
namespace webrtc {
// This class extends RunningStatistics by providing GetPercentile() method,
// while slightly adapting the interface.
class SamplesStatsCounter {
public:
struct StatsSample {
double value;
Timestamp time;
// Sample's specific metadata.
std::map<std::string, std::string> metadata;
};
SamplesStatsCounter();
explicit SamplesStatsCounter(size_t expected_samples_count);
~SamplesStatsCounter();
SamplesStatsCounter(const SamplesStatsCounter&);
SamplesStatsCounter& operator=(const SamplesStatsCounter&);
SamplesStatsCounter(SamplesStatsCounter&&);
SamplesStatsCounter& operator=(SamplesStatsCounter&&);
// Adds sample to the stats in amortized O(1) time.
void AddSample(double value);
void AddSample(StatsSample sample);
// Adds samples from another counter.
void AddSamples(const SamplesStatsCounter& other);
// Returns if there are any values in O(1) time.
bool IsEmpty() const { return samples_.empty(); }
// Returns the amount of samples added into counter in O(1) time.
int64_t NumSamples() const { return stats_.Size(); }
// Returns min in O(1) time. This function may not be called if there are no
// samples.
double GetMin() const {
RTC_DCHECK(!IsEmpty());
return *stats_.GetMin();
}
// Returns max in O(1) time. This function may not be called if there are no
// samples.
double GetMax() const {
RTC_DCHECK(!IsEmpty());
return *stats_.GetMax();
}
// Returns sum in O(1) time. This function may not be called if there are
// no samples.
double GetSum() const {
RTC_DCHECK(!IsEmpty());
return *stats_.GetSum();
}
// Returns average in O(1) time. This function may not be called if there are
// no samples.
double GetAverage() const {
RTC_DCHECK(!IsEmpty());
return *stats_.GetMean();
}
// Returns variance in O(1) time. This function may not be called if there are
// no samples.
double GetVariance() const {
RTC_DCHECK(!IsEmpty());
return *stats_.GetVariance();
}
// Returns standard deviation in O(1) time. This function may not be called if
// there are no samples.
double GetStandardDeviation() const {
RTC_DCHECK(!IsEmpty());
return *stats_.GetStandardDeviation();
}
// Returns percentile in O(nlogn) on first call and in O(1) after, if no
// additions were done. This function may not be called if there are no
// samples.
//
// `percentile` has to be in [0; 1]. 0 percentile is the min in the array and
// 1 percentile is the max in the array.
double GetPercentile(double percentile);
// Returns array view with all samples added into counter. There are no
// guarantees of order, so samples can be in different order comparing to in
// which they were added into counter. Also return value will be invalidate
// after call to any non const method.
rtc::ArrayView<const StatsSample> GetTimedSamples() const { return samples_; }
std::vector<double> GetSamples() const {
std::vector<double> out;
out.reserve(samples_.size());
for (const auto& sample : samples_) {
out.push_back(sample.value);
}
return out;
}
private:
webrtc_impl::RunningStatistics<double> stats_;
std::vector<StatsSample> samples_;
bool sorted_ = false;
};
// Multiply all sample values on `value` and return new SamplesStatsCounter
// with resulted samples. Doesn't change origin SamplesStatsCounter.
SamplesStatsCounter operator*(const SamplesStatsCounter& counter, double value);
inline SamplesStatsCounter operator*(double value,
const SamplesStatsCounter& counter) {
return counter * value;
}
// Divide all sample values on `value` and return new SamplesStatsCounter with
// resulted samples. Doesn't change origin SamplesStatsCounter.
SamplesStatsCounter operator/(const SamplesStatsCounter& counter, double value);
} // namespace webrtc
#endif // API_NUMERICS_SAMPLES_STATS_COUNTER_H_