text: /*
   * Copyright (C) 2010, Google Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1.  Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2.  Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   */
  
  #ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_RESAMPLER_H_
  #define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_RESAMPLER_H_
  
  #include <memory>
  
  #include "third_party/blink/renderer/platform/audio/audio_bus.h"
  #include "third_party/blink/renderer/platform/audio/audio_resampler_kernel.h"
  #include "third_party/blink/renderer/platform/audio/audio_source_provider.h"
  #include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
  #include "third_party/blink/renderer/platform/wtf/vector.h"
  
  namespace blink {
  
  // AudioResampler resamples the audio stream from an AudioSourceProvider.
  // The audio stream may be single or multi-channel.
  // The default constructor defaults to single-channel (mono).
  
  class PLATFORM_EXPORT AudioResampler {
    DISALLOW_NEW();
  
   public:
    AudioResampler();
    AudioResampler(unsigned number_of_channels);
    AudioResampler(const AudioResampler&) = delete;
    AudioResampler& operator=(const AudioResampler&) = delete;
    ~AudioResampler() = default;
  
    // Given an AudioSourceProvider, process() resamples the source stream into
    // destinationBus.
    void Process(AudioSourceProvider*,
                 AudioBus* destination_bus,
                 uint32_t frames_to_process);
  
    // Resets the processing state.
    void Reset();
  
    void ConfigureChannels(unsigned number_of_channels);
  
    // 0 < rate <= MaxRate
    void SetRate(double rate);
    double Rate() const { return rate_; }
  
    static const double kMaxRate;
  
   private:
    double rate_;
    Vector<std::unique_ptr<AudioResamplerKernel>> kernels_;
    scoped_refptr<AudioBus> source_bus_;
  };
  
  }  // namespace blink
  
  #endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_RESAMPLER_H_
  