Line data    Source code

       1             : /*
       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             : 
      11             : #include "webrtc/modules/video_coding/histogram.h"
      12             : 
      13             : #include <algorithm>
      14             : 
      15             : #include "webrtc/modules/video_coding/sequence_number_util.h"
      16             : 
      17             : namespace webrtc {
      18             : namespace video_coding {
      19           0 : Histogram::Histogram(size_t num_buckets, size_t max_num_values) {
      20           0 :   RTC_DCHECK_GT(num_buckets, 0);
      21           0 :   RTC_DCHECK_GT(max_num_values, 0);
      22           0 :   buckets_.resize(num_buckets);
      23           0 :   values_.reserve(max_num_values);
      24           0 :   index_ = 0;
      25           0 : }
      26             : 
      27           0 : void Histogram::Add(size_t value) {
      28           0 :   value = std::min<size_t>(value, buckets_.size() - 1);
      29           0 :   if (index_ < values_.size()) {
      30           0 :     --buckets_[values_[index_]];
      31           0 :     RTC_DCHECK_LT(values_[index_], buckets_.size());
      32           0 :     values_[index_] = value;
      33             :   } else {
      34           0 :     values_.emplace_back(value);
      35             :   }
      36             : 
      37           0 :   ++buckets_[value];
      38           0 :   index_ = (index_ + 1) % values_.capacity();
      39           0 : }
      40             : 
      41           0 : size_t Histogram::InverseCdf(float probability) const {
      42           0 :   RTC_DCHECK_GE(probability, 0.f);
      43           0 :   RTC_DCHECK_LE(probability, 1.f);
      44           0 :   RTC_DCHECK_GT(values_.size(), 0ul);
      45             : 
      46           0 :   size_t bucket = 0;
      47           0 :   float accumulated_probability = 0;
      48           0 :   while (accumulated_probability < probability && bucket < buckets_.size()) {
      49           0 :     accumulated_probability +=
      50           0 :         static_cast<float>(buckets_[bucket]) / values_.size();
      51           0 :     ++bucket;
      52             :   }
      53           0 :   return bucket;
      54             : }
      55             : 
      56           0 : size_t Histogram::NumValues() const {
      57           0 :   return values_.size();
      58             : }
      59             : 
      60             : }  // namespace video_coding
      61             : }  // namespace webrtc