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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.
*/
#include "api/numerics/samples_stats_counter.h"
#include <algorithm>
#include <cmath>
#include "absl/algorithm/container.h"
#include "rtc_base/time_utils.h"
namespace webrtc {
SamplesStatsCounter::SamplesStatsCounter() = default;
SamplesStatsCounter::SamplesStatsCounter(size_t expected_samples_count) {
samples_.reserve(expected_samples_count);
}
SamplesStatsCounter::~SamplesStatsCounter() = default;
SamplesStatsCounter::SamplesStatsCounter(const SamplesStatsCounter&) = default;
SamplesStatsCounter& SamplesStatsCounter::operator=(
const SamplesStatsCounter&) = default;
SamplesStatsCounter::SamplesStatsCounter(SamplesStatsCounter&&) = default;
SamplesStatsCounter& SamplesStatsCounter::operator=(SamplesStatsCounter&&) =
default;
void SamplesStatsCounter::AddSample(double value) {
AddSample(StatsSample{value, Timestamp::Micros(rtc::TimeMicros())});
}
void SamplesStatsCounter::AddSample(StatsSample sample) {
stats_.AddSample(sample.value);
samples_.push_back(sample);
sorted_ = false;
}
void SamplesStatsCounter::AddSamples(const SamplesStatsCounter& other) {
stats_.MergeStatistics(other.stats_);
samples_.insert(samples_.end(), other.samples_.begin(), other.samples_.end());
sorted_ = false;
}
double SamplesStatsCounter::GetPercentile(double percentile) {
RTC_DCHECK(!IsEmpty());
RTC_CHECK_GE(percentile, 0);
RTC_CHECK_LE(percentile, 1);
if (!sorted_) {
absl::c_sort(samples_, [](const StatsSample& a, const StatsSample& b) {
return a.value < b.value;
});
sorted_ = true;
}
const double raw_rank = percentile * (samples_.size() - 1);
double int_part;
double fract_part = std::modf(raw_rank, &int_part);
size_t rank = static_cast<size_t>(int_part);
if (fract_part >= 1.0) {
// It can happen due to floating point calculation error.
rank++;
fract_part -= 1.0;
}
RTC_DCHECK_GE(rank, 0);
RTC_DCHECK_LT(rank, samples_.size());
RTC_DCHECK_GE(fract_part, 0);
RTC_DCHECK_LT(fract_part, 1);
RTC_DCHECK(rank + fract_part == raw_rank);
const double low = samples_[rank].value;
const double high = samples_[std::min(rank + 1, samples_.size() - 1)].value;
return low + fract_part * (high - low);
}
SamplesStatsCounter operator*(const SamplesStatsCounter& counter,
double value) {
SamplesStatsCounter out;
for (const auto& sample : counter.GetTimedSamples()) {
out.AddSample(
SamplesStatsCounter::StatsSample{sample.value * value, sample.time});
}
return out;
}
SamplesStatsCounter operator/(const SamplesStatsCounter& counter,
double value) {
SamplesStatsCounter out;
for (const auto& sample : counter.GetTimedSamples()) {
out.AddSample(
SamplesStatsCounter::StatsSample{sample.value / value, sample.time});
}
return out;
}
} // namespace webrtc