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      1 /*
      2  * Copyright (C) 2010, Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1.  Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2.  Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     16  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     17  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     18  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     19  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
     20  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     22  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     23  */
     24 
     25 #ifndef BiquadProcessor_h
     26 #define BiquadProcessor_h
     27 
     28 #include "platform/audio/AudioDSPKernel.h"
     29 #include "platform/audio/AudioDSPKernelProcessor.h"
     30 #include "platform/audio/Biquad.h"
     31 #include "modules/webaudio/AudioNode.h"
     32 #include "modules/webaudio/AudioParam.h"
     33 #include "wtf/RefPtr.h"
     34 
     35 namespace WebCore {
     36 
     37 // BiquadProcessor is an AudioDSPKernelProcessor which uses Biquad objects to implement several common filters.
     38 
     39 class BiquadProcessor FINAL : public AudioDSPKernelProcessor {
     40 public:
     41     enum FilterType {
     42         LowPass = 0,
     43         HighPass = 1,
     44         BandPass = 2,
     45         LowShelf = 3,
     46         HighShelf = 4,
     47         Peaking = 5,
     48         Notch = 6,
     49         Allpass = 7
     50     };
     51 
     52     BiquadProcessor(AudioContext*, float sampleRate, size_t numberOfChannels, bool autoInitialize);
     53 
     54     virtual ~BiquadProcessor();
     55 
     56     virtual PassOwnPtr<AudioDSPKernel> createKernel() OVERRIDE;
     57 
     58     virtual void process(const AudioBus* source, AudioBus* destination, size_t framesToProcess) OVERRIDE;
     59 
     60     // Get the magnitude and phase response of the filter at the given
     61     // set of frequencies (in Hz). The phase response is in radians.
     62     void getFrequencyResponse(int nFrequencies,
     63                               const float* frequencyHz,
     64                               float* magResponse,
     65                               float* phaseResponse);
     66 
     67     void checkForDirtyCoefficients();
     68 
     69     bool filterCoefficientsDirty() const { return m_filterCoefficientsDirty; }
     70     bool hasSampleAccurateValues() const { return m_hasSampleAccurateValues; }
     71 
     72     AudioParam* parameter1() { return m_parameter1.get(); }
     73     AudioParam* parameter2() { return m_parameter2.get(); }
     74     AudioParam* parameter3() { return m_parameter3.get(); }
     75     AudioParam* parameter4() { return m_parameter4.get(); }
     76 
     77     FilterType type() const { return m_type; }
     78     void setType(FilterType);
     79 
     80 private:
     81     FilterType m_type;
     82 
     83     RefPtrWillBePersistent<AudioParam> m_parameter1;
     84     RefPtrWillBePersistent<AudioParam> m_parameter2;
     85     RefPtrWillBePersistent<AudioParam> m_parameter3;
     86     RefPtrWillBePersistent<AudioParam> m_parameter4;
     87 
     88     // so DSP kernels know when to re-compute coefficients
     89     bool m_filterCoefficientsDirty;
     90 
     91     // Set to true if any of the filter parameters are sample-accurate.
     92     bool m_hasSampleAccurateValues;
     93 };
     94 
     95 } // namespace WebCore
     96 
     97 #endif // BiquadProcessor_h
     98