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      1 /*
      2  * Copyright (C) 2011, 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 WaveShaperProcessor_h
     26 #define WaveShaperProcessor_h
     27 
     28 #include "core/platform/audio/AudioDSPKernel.h"
     29 #include "core/platform/audio/AudioDSPKernelProcessor.h"
     30 #include "modules/webaudio/AudioNode.h"
     31 #include "wtf/Float32Array.h"
     32 #include "wtf/RefPtr.h"
     33 #include "wtf/Threading.h"
     34 
     35 namespace WebCore {
     36 
     37 // WaveShaperProcessor is an AudioDSPKernelProcessor which uses WaveShaperDSPKernel objects to implement non-linear distortion effects.
     38 
     39 class WaveShaperProcessor : public AudioDSPKernelProcessor {
     40 public:
     41     enum OverSampleType {
     42         OverSampleNone,
     43         OverSample2x,
     44         OverSample4x
     45     };
     46 
     47     WaveShaperProcessor(float sampleRate, size_t numberOfChannels);
     48 
     49     virtual ~WaveShaperProcessor();
     50 
     51     virtual PassOwnPtr<AudioDSPKernel> createKernel();
     52 
     53     virtual void process(const AudioBus* source, AudioBus* destination, size_t framesToProcess);
     54 
     55     void setCurve(Float32Array*);
     56     Float32Array* curve() { return m_curve.get(); }
     57 
     58     void setOversample(OverSampleType);
     59     OverSampleType oversample() const { return m_oversample; }
     60 
     61 private:
     62     // m_curve represents the non-linear shaping curve.
     63     RefPtr<Float32Array> m_curve;
     64 
     65     OverSampleType m_oversample;
     66 
     67     // This synchronizes process() with setCurve().
     68     mutable Mutex m_processLock;
     69 };
     70 
     71 } // namespace WebCore
     72 
     73 #endif // WaveShaperProcessor_h
     74