1 /*
2 * Copyright (c) 2018 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 #include "rtc_base/numerics/samples_stats_counter.h"
12
13 #include <cmath>
14
15 #include "absl/algorithm/container.h"
16 #include "rtc_base/time_utils.h"
17
18 namespace webrtc {
19
20 SamplesStatsCounter::SamplesStatsCounter() = default;
21 SamplesStatsCounter::~SamplesStatsCounter() = default;
22 SamplesStatsCounter::SamplesStatsCounter(const SamplesStatsCounter&) = default;
23 SamplesStatsCounter& SamplesStatsCounter::operator=(
24 const SamplesStatsCounter&) = default;
25 SamplesStatsCounter::SamplesStatsCounter(SamplesStatsCounter&&) = default;
26 SamplesStatsCounter& SamplesStatsCounter::operator=(SamplesStatsCounter&&) =
27 default;
28
AddSample(double value)29 void SamplesStatsCounter::AddSample(double value) {
30 AddSample(StatsSample{value, Timestamp::Micros(rtc::TimeMicros())});
31 }
32
AddSample(StatsSample sample)33 void SamplesStatsCounter::AddSample(StatsSample sample) {
34 stats_.AddSample(sample.value);
35 samples_.push_back(sample);
36 sorted_ = false;
37 }
38
AddSamples(const SamplesStatsCounter & other)39 void SamplesStatsCounter::AddSamples(const SamplesStatsCounter& other) {
40 stats_.MergeStatistics(other.stats_);
41 samples_.insert(samples_.end(), other.samples_.begin(), other.samples_.end());
42 sorted_ = false;
43 }
44
GetPercentile(double percentile)45 double SamplesStatsCounter::GetPercentile(double percentile) {
46 RTC_DCHECK(!IsEmpty());
47 RTC_CHECK_GE(percentile, 0);
48 RTC_CHECK_LE(percentile, 1);
49 if (!sorted_) {
50 absl::c_sort(samples_, [](const StatsSample& a, const StatsSample& b) {
51 return a.value < b.value;
52 });
53 sorted_ = true;
54 }
55 const double raw_rank = percentile * (samples_.size() - 1);
56 double int_part;
57 double fract_part = std::modf(raw_rank, &int_part);
58 size_t rank = static_cast<size_t>(int_part);
59 if (fract_part >= 1.0) {
60 // It can happen due to floating point calculation error.
61 rank++;
62 fract_part -= 1.0;
63 }
64
65 RTC_DCHECK_GE(rank, 0);
66 RTC_DCHECK_LT(rank, samples_.size());
67 RTC_DCHECK_GE(fract_part, 0);
68 RTC_DCHECK_LT(fract_part, 1);
69 RTC_DCHECK(rank + fract_part == raw_rank);
70
71 const double low = samples_[rank].value;
72 const double high = samples_[std::min(rank + 1, samples_.size() - 1)].value;
73 return low + fract_part * (high - low);
74 }
75
operator *(const SamplesStatsCounter & counter,double value)76 SamplesStatsCounter operator*(const SamplesStatsCounter& counter,
77 double value) {
78 SamplesStatsCounter out;
79 for (const auto& sample : counter.GetTimedSamples()) {
80 out.AddSample(
81 SamplesStatsCounter::StatsSample{sample.value * value, sample.time});
82 }
83 return out;
84 }
85
operator /(const SamplesStatsCounter & counter,double value)86 SamplesStatsCounter operator/(const SamplesStatsCounter& counter,
87 double value) {
88 SamplesStatsCounter out;
89 for (const auto& sample : counter.GetTimedSamples()) {
90 out.AddSample(
91 SamplesStatsCounter::StatsSample{sample.value / value, sample.time});
92 }
93 return out;
94 }
95
96 } // namespace webrtc
97