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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 "AudioDSPKernel.h"
     29 #include "AudioDSPKernelProcessor.h"
     30 #include "AudioNode.h"
     31 #include "AudioParam.h"
     32 #include "Biquad.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 : public AudioDSPKernelProcessor {
     40 public:
     41     enum FilterType {
     42         LowPass2,
     43         HighPass2,
     44         Peaking,
     45         Allpass,
     46         LowShelf,
     47         HighShelf
     48     };
     49 
     50     BiquadProcessor(FilterType, double sampleRate, size_t numberOfChannels, bool autoInitialize = true);
     51     virtual ~BiquadProcessor();
     52 
     53     virtual PassOwnPtr<AudioDSPKernel> createKernel();
     54 
     55     virtual void process(AudioBus* source, AudioBus* destination, size_t framesToProcess);
     56 
     57     bool filterCoefficientsDirty() const { return m_filterCoefficientsDirty; }
     58 
     59     AudioParam* parameter1() { return m_parameter1.get(); }
     60     AudioParam* parameter2() { return m_parameter2.get(); }
     61     AudioParam* parameter3() { return m_parameter3.get(); }
     62 
     63     FilterType type() const { return m_type; }
     64 
     65 private:
     66     FilterType m_type;
     67 
     68     RefPtr<AudioParam> m_parameter1;
     69     RefPtr<AudioParam> m_parameter2;
     70     RefPtr<AudioParam> m_parameter3;
     71 
     72     // so DSP kernels know when to re-compute coefficients
     73     bool m_filterCoefficientsDirty;
     74 };
     75 
     76 } // namespace WebCore
     77 
     78 #endif // BiquadProcessor_h
     79