third_party/WebKit/Source/platform/audio/ReverbAccumulationBuffer.h

   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  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef ReverbAccumulationBuffer_h
  30 #define ReverbAccumulationBuffer_h
  31
  32 #include "platform/PlatformExport.h"
  33 #include "platform/audio/AudioArray.h"
  34
  35 namespace blink {
  36
  37 // ReverbAccumulationBuffer is a circular delay buffer with one client reading from it and multiple clients
  38 // writing/accumulating to it at different delay offsets from the read position.  The read operation will zero the memory
  39 // just read from the buffer, so it will be ready for accumulation the next time around.
  40 class PLATFORM_EXPORT ReverbAccumulationBuffer {
  41 public:
  42     ReverbAccumulationBuffer(size_t length);
  43
  44     // This will read from, then clear-out numberOfFrames
  45     void readAndClear(float* destination, size_t numberOfFrames);
  46
  47     // Each ReverbConvolverStage will accumulate its output at the appropriate delay from the read position.
  48     // We need to pass in and update readIndex here, since each ReverbConvolverStage may be running in
  49     // a different thread than the realtime thread calling ReadAndClear() and maintaining m_readIndex
  50     // Returns the writeIndex where the accumulation took place
  51     int accumulate(float* source, size_t numberOfFrames, int* readIndex, size_t delayFrames);
  52
  53     size_t readIndex() const { return m_readIndex; }
  54     void updateReadIndex(int* readIndex, size_t numberOfFrames) const;
  55
  56     size_t readTimeFrame() const { return m_readTimeFrame; }
  57
  58     void reset();
  59
  60 private:
  61     AudioFloatArray m_buffer;
  62     size_t m_readIndex;
  63     size_t m_readTimeFrame; // for debugging (frame on continuous timeline)
  64 };
  65
  66 } // namespace blink
  67
  68 #endif // ReverbAccumulationBuffer_h