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philipel5ab4c6d2016-03-08 11:36:151/*
2 * Copyright (c) 2016 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 "modules/video_coding/histogram.h"
philipel5ab4c6d2016-03-08 11:36:1512
13#include <algorithm>
14
Yves Gerey3e707812018-11-28 15:47:4915#include "rtc_base/checks.h"
philipel5ab4c6d2016-03-08 11:36:1516
17namespace webrtc {
18namespace video_coding {
19Histogram::Histogram(size_t num_buckets, size_t max_num_values) {
kwibergaf476c72016-11-28 23:21:3920 RTC_DCHECK_GT(num_buckets, 0);
21 RTC_DCHECK_GT(max_num_values, 0);
philipel5ab4c6d2016-03-08 11:36:1522 buckets_.resize(num_buckets);
23 values_.reserve(max_num_values);
24 index_ = 0;
25}
26
27void Histogram::Add(size_t value) {
philipel5ab4c6d2016-03-08 11:36:1528 value = std::min<size_t>(value, buckets_.size() - 1);
29 if (index_ < values_.size()) {
30 --buckets_[values_[index_]];
31 RTC_DCHECK_LT(values_[index_], buckets_.size());
32 values_[index_] = value;
33 } else {
34 values_.emplace_back(value);
35 }
36
37 ++buckets_[value];
38 index_ = (index_ + 1) % values_.capacity();
39}
40
41size_t Histogram::InverseCdf(float probability) const {
42 RTC_DCHECK_GE(probability, 0.f);
43 RTC_DCHECK_LE(probability, 1.f);
44 RTC_DCHECK_GT(values_.size(), 0ul);
45
46 size_t bucket = 0;
47 float accumulated_probability = 0;
48 while (accumulated_probability < probability && bucket < buckets_.size()) {
49 accumulated_probability +=
50 static_cast<float>(buckets_[bucket]) / values_.size();
51 ++bucket;
52 }
53 return bucket;
54}
55
56size_t Histogram::NumValues() const {
57 return values_.size();
58}
59
60} // namespace video_coding
61} // namespace webrtc