third_party/WebKit/Source/modules/webaudio/IIRProcessor.h

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef IIRProcessor_h
#define IIRProcessor_h

#include "modules/webaudio/AudioNode.h"
#include "platform/audio/AudioDSPKernel.h"
#include "platform/audio/AudioDSPKernelProcessor.h"
#include "platform/audio/IIRFilter.h"
#include <memory>

namespace blink {

class IIRDSPKernel;

class IIRProcessor final : public AudioDSPKernelProcessor {
 public:
  IIRProcessor(float sampleRate,
               size_t numberOfChannels,
               const Vector<double>& feedforwardCoef,
               const Vector<double>& feedbackCoef);
  ~IIRProcessor() override;

  std::unique_ptr<AudioDSPKernel> createKernel() override;

  void process(const AudioBus* source,
               AudioBus* destination,
               size_t framesToProcess) override;

  // Get the magnitude and phase response of the filter at the given
  // set of frequencies (in Hz). The phase response is in radians.
  void getFrequencyResponse(int nFrequencies,
                            const float* frequencyHz,
                            float* magResponse,
                            float* phaseResponse);

  AudioDoubleArray* feedback() { return &m_feedback; }
  AudioDoubleArray* feedforward() { return &m_feedforward; }

 private:
  // The feedback and feedforward filter coefficients for the IIR filter.
  AudioDoubleArray m_feedback;
  AudioDoubleArray m_feedforward;
  // This holds the IIR kernel for computing the frequency response.
  std::unique_ptr<IIRDSPKernel> m_responseKernel;
};

}  // namespace blink

#endif  // IIRProcessor_h