Introduce PushPullFIFO class and remove other FIFOs

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

-/*
- * Copyright (C) 2012 Google Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
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- *
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- * 2.  Redistributions in binary form must reproduce the above copyright
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- *     its contributors may be used to endorse or promote products derived
- *     from this software without specific prior written permission.
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-
-#ifndef AudioFIFO_h
-#define AudioFIFO_h
-
-#include "platform/audio/AudioBus.h"
-#include "wtf/Allocator.h"
-
-namespace blink {
-
-class AudioFIFO {
-  USING_FAST_MALLOC(AudioFIFO);
-  WTF_MAKE_NONCOPYABLE(AudioFIFO);
-
- public:
-  // Create a FIFO large enough to hold |fifoLength| frames of data of
-  // |numberOfChannels| channels.
-  AudioFIFO(unsigned numberOfChannels, size_t fifoLength);
-
-  // Push the data from the bus into the FIFO.
-  void push(const AudioBus*);
-
-  // Consume |framesToConsume| frames of data from the FIFO and put them in
-  // |destination|. The corresponding frames are removed from the FIFO.
-  void consume(AudioBus* destination, size_t framesToConsume);
-
-  // Number of frames of data that are currently in the FIFO.
-  size_t framesInFifo() const { return m_framesInFifo; }
-
- private:
-  // Update the FIFO index by the step, with appropriate wrapping around the
-  // endpoint.
-  int updateIndex(int index, int step) { return (index + step) % m_fifoLength; }
-
-  void findWrapLengths(size_t index,
-                       size_t providerSize,
-                       size_t& part1Length,
-                       size_t& part2Length);
-
-  // The FIFO itself. In reality, the FIFO is a circular buffer.
-  RefPtr<AudioBus> m_fifoAudioBus;
-
-  // The total available space in the FIFO.
-  size_t m_fifoLength;
-
-  // The number of actual elements in the FIFO
-  size_t m_framesInFifo;
-
-  // Where to start reading from the FIFO.
-  size_t m_readIndex;
-
-  // Where to start writing to the FIFO.
-  size_t m_writeIndex;
-};
-
-}  // namespace blink
-
-#endif  // AudioFIFO.h