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 "api/numerics/samples_stats_counter.h"
12
13 #include <algorithm>
14 #include <cmath>
15
16 #include "absl/algorithm/container.h"
17 #include "rtc_base/time_utils.h"
18
19 namespace webrtc {
20
21 SamplesStatsCounter::SamplesStatsCounter() = default;
SamplesStatsCounter(size_t expected_samples_count)22 SamplesStatsCounter::SamplesStatsCounter(size_t expected_samples_count) {
23 samples_.reserve(expected_samples_count);
24 }
25
26 SamplesStatsCounter::~SamplesStatsCounter() = default;
27 SamplesStatsCounter::SamplesStatsCounter(const SamplesStatsCounter&) = default;
28 SamplesStatsCounter& SamplesStatsCounter::operator=(
29 const SamplesStatsCounter&) = default;
30 SamplesStatsCounter::SamplesStatsCounter(SamplesStatsCounter&&) = default;
31 SamplesStatsCounter& SamplesStatsCounter::operator=(SamplesStatsCounter&&) =
32 default;
33
AddSample(double value)34 void SamplesStatsCounter::AddSample(double value) {
35 AddSample(StatsSample{value, Timestamp::Micros(rtc::TimeMicros())});
36 }
37
AddSample(StatsSample sample)38 void SamplesStatsCounter::AddSample(StatsSample sample) {
39 stats_.AddSample(sample.value);
40 samples_.push_back(sample);
41 sorted_ = false;
42 }
43
AddSamples(const SamplesStatsCounter & other)44 void SamplesStatsCounter::AddSamples(const SamplesStatsCounter& other) {
45 stats_.MergeStatistics(other.stats_);
46 samples_.insert(samples_.end(), other.samples_.begin(), other.samples_.end());
47 sorted_ = false;
48 }
49
GetPercentile(double percentile)50 double SamplesStatsCounter::GetPercentile(double percentile) {
51 RTC_DCHECK(!IsEmpty());
52 RTC_CHECK_GE(percentile, 0);
53 RTC_CHECK_LE(percentile, 1);
54 if (!sorted_) {
55 absl::c_sort(samples_, [](const StatsSample& a, const StatsSample& b) {
56 return a.value < b.value;
57 });
58 sorted_ = true;
59 }
60 const double raw_rank = percentile * (samples_.size() - 1);
61 double int_part;
62 double fract_part = std::modf(raw_rank, &int_part);
63 size_t rank = static_cast<size_t>(int_part);
64 if (fract_part >= 1.0) {
65 // It can happen due to floating point calculation error.
66 rank++;
67 fract_part -= 1.0;
68 }
69
70 RTC_DCHECK_GE(rank, 0);
71 RTC_DCHECK_LT(rank, samples_.size());
72 RTC_DCHECK_GE(fract_part, 0);
73 RTC_DCHECK_LT(fract_part, 1);
74 RTC_DCHECK(rank + fract_part == raw_rank);
75
76 const double low = samples_[rank].value;
77 const double high = samples_[std::min(rank + 1, samples_.size() - 1)].value;
78 return low + fract_part * (high - low);
79 }
80
operator *(const SamplesStatsCounter & counter,double value)81 SamplesStatsCounter operator*(const SamplesStatsCounter& counter,
82 double value) {
83 SamplesStatsCounter out;
84 for (const auto& sample : counter.GetTimedSamples()) {
85 out.AddSample(
86 SamplesStatsCounter::StatsSample{sample.value * value, sample.time});
87 }
88 return out;
89 }
90
operator /(const SamplesStatsCounter & counter,double value)91 SamplesStatsCounter operator/(const SamplesStatsCounter& counter,
92 double value) {
93 SamplesStatsCounter out;
94 for (const auto& sample : counter.GetTimedSamples()) {
95 out.AddSample(
96 SamplesStatsCounter::StatsSample{sample.value / value, sample.time});
97 }
98 return out;
99 }
100
101 } // namespace webrtc
102