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sprang@webrtc.org37968a92013-12-03 10:31:591/*
2 * Copyright (c) 2013 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
Mirko Bonadei92ea95e2017-09-15 04:47:3111#include "rtc_base/rate_statistics.h"
sprang@webrtc.org37968a92013-12-03 10:31:5912
Stefan Holmerfb8fc532016-04-22 13:48:2313#include <algorithm>
14
Mirko Bonadei92ea95e2017-09-15 04:47:3115#include "rtc_base/checks.h"
henrike@webrtc.orgf2aafe42014-04-29 17:54:1716
sprang@webrtc.org37968a92013-12-03 10:31:5917namespace webrtc {
18
Erik Språng51e60302016-06-10 20:13:2119RateStatistics::RateStatistics(int64_t window_size_ms, float scale)
20 : buckets_(new Bucket[window_size_ms]()),
sprang@webrtc.org37968a92013-12-03 10:31:5921 accumulated_count_(0),
Erik Språng51e60302016-06-10 20:13:2122 num_samples_(0),
23 oldest_time_(-window_size_ms),
sprang@webrtc.org37968a92013-12-03 10:31:5924 oldest_index_(0),
Erik Språng51e60302016-06-10 20:13:2125 scale_(scale),
26 max_window_size_ms_(window_size_ms),
27 current_window_size_ms_(max_window_size_ms_) {}
sprang@webrtc.org37968a92013-12-03 10:31:5928
tkchinf75d0082016-02-24 06:49:4229RateStatistics::~RateStatistics() {}
sprang@webrtc.org37968a92013-12-03 10:31:5930
31void RateStatistics::Reset() {
32 accumulated_count_ = 0;
Erik Språng51e60302016-06-10 20:13:2133 num_samples_ = 0;
34 oldest_time_ = -max_window_size_ms_;
sprang@webrtc.org37968a92013-12-03 10:31:5935 oldest_index_ = 0;
Erik Språng51e60302016-06-10 20:13:2136 current_window_size_ms_ = max_window_size_ms_;
37 for (int64_t i = 0; i < max_window_size_ms_; i++)
38 buckets_[i] = Bucket();
sprang@webrtc.org37968a92013-12-03 10:31:5939}
40
pkasting@chromium.org4591fbd2014-11-20 22:28:1441void RateStatistics::Update(size_t count, int64_t now_ms) {
sprang@webrtc.org37968a92013-12-03 10:31:5942 if (now_ms < oldest_time_) {
43 // Too old data is ignored.
44 return;
45 }
46
47 EraseOld(now_ms);
48
Erik Språng51e60302016-06-10 20:13:2149 // First ever sample, reset window to start now.
50 if (!IsInitialized())
51 oldest_time_ = now_ms;
52
53 uint32_t now_offset = static_cast<uint32_t>(now_ms - oldest_time_);
54 RTC_DCHECK_LT(now_offset, max_window_size_ms_);
55 uint32_t index = oldest_index_ + now_offset;
56 if (index >= max_window_size_ms_)
57 index -= max_window_size_ms_;
58 buckets_[index].sum += count;
59 ++buckets_[index].samples;
sprang@webrtc.org37968a92013-12-03 10:31:5960 accumulated_count_ += count;
Erik Språng51e60302016-06-10 20:13:2161 ++num_samples_;
sprang@webrtc.org37968a92013-12-03 10:31:5962}
63
sprangcd349d92016-07-13 16:11:2864rtc::Optional<uint32_t> RateStatistics::Rate(int64_t now_ms) const {
65 // Yeah, this const_cast ain't pretty, but the alternative is to declare most
66 // of the members as mutable...
67 const_cast<RateStatistics*>(this)->EraseOld(now_ms);
Erik Språng51e60302016-06-10 20:13:2168
69 // If window is a single bucket or there is only one sample in a data set that
70 // has not grown to the full window size, treat this as rate unavailable.
71 int64_t active_window_size = now_ms - oldest_time_ + 1;
72 if (num_samples_ == 0 || active_window_size <= 1 ||
73 (num_samples_ <= 1 && active_window_size < current_window_size_ms_)) {
Oskar Sundbomf8200032017-11-16 09:57:2674 return rtc::nullopt;
Erik Språng51e60302016-06-10 20:13:2175 }
76
77 float scale = scale_ / active_window_size;
Oskar Sundbomf8200032017-11-16 09:57:2678 return static_cast<uint32_t>(accumulated_count_ * scale + 0.5f);
sprang@webrtc.org37968a92013-12-03 10:31:5979}
80
81void RateStatistics::EraseOld(int64_t now_ms) {
Erik Språng51e60302016-06-10 20:13:2182 if (!IsInitialized())
sprang@webrtc.org37968a92013-12-03 10:31:5983 return;
Erik Språng51e60302016-06-10 20:13:2184
85 // New oldest time that is included in data set.
86 int64_t new_oldest_time = now_ms - current_window_size_ms_ + 1;
87
88 // New oldest time is older than the current one, no need to cull data.
89 if (new_oldest_time <= oldest_time_)
90 return;
91
92 // Loop over buckets and remove too old data points.
93 while (num_samples_ > 0 && oldest_time_ < new_oldest_time) {
94 const Bucket& oldest_bucket = buckets_[oldest_index_];
95 RTC_DCHECK_GE(accumulated_count_, oldest_bucket.sum);
96 RTC_DCHECK_GE(num_samples_, oldest_bucket.samples);
97 accumulated_count_ -= oldest_bucket.sum;
98 num_samples_ -= oldest_bucket.samples;
99 buckets_[oldest_index_] = Bucket();
100 if (++oldest_index_ >= max_window_size_ms_)
sprang@webrtc.org37968a92013-12-03 10:31:59101 oldest_index_ = 0;
sprang@webrtc.org37968a92013-12-03 10:31:59102 ++oldest_time_;
sprang@webrtc.org37968a92013-12-03 10:31:59103 }
104 oldest_time_ = new_oldest_time;
105}
106
Erik Språng51e60302016-06-10 20:13:21107bool RateStatistics::SetWindowSize(int64_t window_size_ms, int64_t now_ms) {
108 if (window_size_ms <= 0 || window_size_ms > max_window_size_ms_)
109 return false;
110
111 current_window_size_ms_ = window_size_ms;
112 EraseOld(now_ms);
113 return true;
114}
115
sprangcd349d92016-07-13 16:11:28116bool RateStatistics::IsInitialized() const {
Erik Språng51e60302016-06-10 20:13:21117 return oldest_time_ != -max_window_size_ms_;
118}
119
sprang@webrtc.org37968a92013-12-03 10:31:59120} // namespace webrtc