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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 are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef AudioProcessor_h
     32 #define AudioProcessor_h
     33 
     34 namespace WebCore {
     35 
     36 class AudioBus;
     37 
     38 // AudioProcessor is an abstract base class representing an audio signal processing object with a single input and a single output,
     39 // where the number of input channels equals the number of output channels.  It can be used as one part of a complex DSP algorithm,
     40 // or as the processor for a basic (one input - one output) AudioNode.
     41 
     42 class AudioProcessor {
     43 public:
     44     AudioProcessor(double sampleRate)
     45         : m_initialized(false)
     46         , m_sampleRate(sampleRate)
     47     {
     48     }
     49 
     50     virtual ~AudioProcessor() { }
     51 
     52     // Full initialization can be done here instead of in the constructor.
     53     virtual void initialize() = 0;
     54     virtual void uninitialize() = 0;
     55 
     56     // Processes the source to destination bus.  The number of channels must match in source and destination.
     57     virtual void process(AudioBus* source, AudioBus* destination, size_t framesToProcess) = 0;
     58 
     59     // Resets filter state
     60     virtual void reset() = 0;
     61 
     62     virtual void setNumberOfChannels(unsigned) = 0;
     63 
     64     bool isInitialized() const { return m_initialized; }
     65 
     66     double sampleRate() const { return m_sampleRate; }
     67 
     68 protected:
     69     bool m_initialized;
     70     double m_sampleRate;
     71 };
     72 
     73 } // namespace WebCore
     74 
     75 #endif // AudioProcessor_h
     76