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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 AudioDelayDSPKernel_h
     26 #define AudioDelayDSPKernel_h
     27 
     28 #include "platform/audio/AudioArray.h"
     29 #include "platform/audio/AudioDSPKernel.h"
     30 
     31 namespace WebCore {
     32 
     33 class PLATFORM_EXPORT AudioDelayDSPKernel : public AudioDSPKernel {
     34 public:
     35     AudioDelayDSPKernel(double maxDelayTime, float sampleRate);
     36 
     37     virtual void process(const float* source, float* destination, size_t framesToProcess);
     38     virtual void reset();
     39 
     40     double maxDelayTime() const { return m_maxDelayTime; }
     41 
     42     void setDelayFrames(double numberOfFrames) { m_desiredDelayFrames = numberOfFrames; }
     43 
     44     virtual double tailTime() const OVERRIDE;
     45     virtual double latencyTime() const OVERRIDE;
     46 
     47 protected:
     48     AudioDelayDSPKernel(AudioDSPKernelProcessor*, size_t processingSizeInFrames);
     49 
     50     virtual bool hasSampleAccurateValues();
     51     virtual void calculateSampleAccurateValues(float* delayTimes, size_t framesToProcess);
     52     virtual double delayTime(float sampleRate);
     53 
     54     AudioFloatArray m_buffer;
     55     double m_maxDelayTime;
     56     int m_writeIndex;
     57     double m_currentDelayTime;
     58     double m_smoothingRate;
     59     bool m_firstTime;
     60     double m_desiredDelayFrames;
     61 
     62     AudioFloatArray m_delayTimes;
     63 
     64     size_t bufferLengthForDelay(double delayTime, double sampleRate) const;
     65 };
     66 
     67 } // namespace WebCore
     68 
     69 #endif // AudioDelayDSPKernel_h
     70