tor-browser

The Tor Browser
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block.h (2870B)

      1 /*
      2 *  Copyright (c) 2022 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 #ifndef MODULES_AUDIO_PROCESSING_AEC3_BLOCK_H_
     12 #define MODULES_AUDIO_PROCESSING_AEC3_BLOCK_H_
     13 
     14 #include <algorithm>
     15 #include <utility>
     16 #include <vector>
     17 
     18 #include "api/array_view.h"
     19 #include "modules/audio_processing/aec3/aec3_common.h"
     20 
     21 namespace webrtc {
     22 
     23 // Contains one or more channels of 4 milliseconds of audio data.
     24 // The audio is split in one or more frequency bands, each with a sampling
     25 // rate of 16 kHz.
     26 class Block {
     27 public:
     28  Block(int num_bands, int num_channels, float default_value = 0.0f)
     29      : num_bands_(num_bands),
     30        num_channels_(num_channels),
     31        data_(num_bands * num_channels * kBlockSize, default_value) {}
     32 
     33  // Returns the number of bands.
     34  int NumBands() const { return num_bands_; }
     35 
     36  // Returns the number of channels.
     37  int NumChannels() const { return num_channels_; }
     38 
     39  // Modifies the number of channels and sets all samples to zero.
     40  void SetNumChannels(int num_channels) {
     41    num_channels_ = num_channels;
     42    data_.resize(num_bands_ * num_channels_ * kBlockSize);
     43    std::fill(data_.begin(), data_.end(), 0.0f);
     44  }
     45 
     46  // Iterators for accessing the data.
     47  auto begin(int band, int channel) {
     48    return data_.begin() + GetIndex(band, channel);
     49  }
     50 
     51  auto begin(int band, int channel) const {
     52    return data_.begin() + GetIndex(band, channel);
     53  }
     54 
     55  auto end(int band, int channel) { return begin(band, channel) + kBlockSize; }
     56 
     57  auto end(int band, int channel) const {
     58    return begin(band, channel) + kBlockSize;
     59  }
     60 
     61  // Access data via ArrayView.
     62  ArrayView<float, kBlockSize> View(int band, int channel) {
     63    return ArrayView<float, kBlockSize>(&data_[GetIndex(band, channel)],
     64                                        kBlockSize);
     65  }
     66 
     67  ArrayView<const float, kBlockSize> View(int band, int channel) const {
     68    return ArrayView<const float, kBlockSize>(&data_[GetIndex(band, channel)],
     69                                              kBlockSize);
     70  }
     71 
     72  // Lets two Blocks swap audio data.
     73  void Swap(Block& b) {
     74    std::swap(num_bands_, b.num_bands_);
     75    std::swap(num_channels_, b.num_channels_);
     76    data_.swap(b.data_);
     77  }
     78 
     79 private:
     80  // Returns the index of the first sample of the requested |band| and
     81  // |channel|.
     82  int GetIndex(int band, int channel) const {
     83    return (band * num_channels_ + channel) * kBlockSize;
     84  }
     85 
     86  int num_bands_;
     87  int num_channels_;
     88  std::vector<float> data_;
     89 };
     90 
     91 }  // namespace webrtc
     92 #endif  // MODULES_AUDIO_PROCESSING_AEC3_BLOCK_H_