62 lines
1.6 KiB
C++
62 lines
1.6 KiB
C++
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/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/video_coding/histogram.h"
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#include <algorithm>
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#include "rtc_base/checks.h"
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namespace webrtc {
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namespace video_coding {
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Histogram::Histogram(size_t num_buckets, size_t max_num_values) {
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RTC_DCHECK_GT(num_buckets, 0);
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RTC_DCHECK_GT(max_num_values, 0);
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buckets_.resize(num_buckets);
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values_.reserve(max_num_values);
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index_ = 0;
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}
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void Histogram::Add(size_t value) {
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value = std::min<size_t>(value, buckets_.size() - 1);
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if (index_ < values_.size()) {
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--buckets_[values_[index_]];
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RTC_DCHECK_LT(values_[index_], buckets_.size());
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values_[index_] = value;
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} else {
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values_.emplace_back(value);
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}
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++buckets_[value];
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index_ = (index_ + 1) % values_.capacity();
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}
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size_t Histogram::InverseCdf(float probability) const {
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RTC_DCHECK_GE(probability, 0.f);
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RTC_DCHECK_LE(probability, 1.f);
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RTC_DCHECK_GT(values_.size(), 0ul);
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size_t bucket = 0;
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float accumulated_probability = 0;
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while (accumulated_probability < probability && bucket < buckets_.size()) {
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accumulated_probability +=
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static_cast<float>(buckets_[bucket]) / values_.size();
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++bucket;
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}
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return bucket;
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}
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size_t Histogram::NumValues() const {
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return values_.size();
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}
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} // namespace video_coding
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} // namespace webrtc
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