Introduce PushPullFIFO class and remove other FIFOs

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

-/*
- * 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
- * are met:
- *
- * 1.  Redistributions of source code must retain the above copyright
- *     notice, this list of conditions and the following disclaimer.
- * 2.  Redistributions in binary form must reproduce the above copyright
- *     notice, this list of conditions and the following disclaimer in the
- *     documentation and/or other materials provided with the distribution.
- * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
- *     its contributors may be used to endorse or promote products derived
- *     from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
- * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "platform/audio/AudioFIFO.h"
-
-namespace blink {
-
-AudioFIFO::AudioFIFO(unsigned numberOfChannels, size_t fifoLength)
-    : m_fifoAudioBus(AudioBus::create(numberOfChannels, fifoLength)),
-      m_fifoLength(fifoLength),
-      m_framesInFifo(0),
-      m_readIndex(0),
-      m_writeIndex(0) {}
-
-void AudioFIFO::consume(AudioBus* destination, size_t framesToConsume) {
-  bool isGood = destination && (framesToConsume <= m_fifoLength) &&
-                (framesToConsume <= m_framesInFifo) &&
-                (destination->length() >= framesToConsume);
-  ASSERT(isGood);
-  if (!isGood)
-    return;
-
-  // Copy the requested number of samples to the destination.
-
-  size_t part1Length;
-  size_t part2Length;
-  findWrapLengths(m_readIndex, framesToConsume, part1Length, part2Length);
-
-  size_t numberOfChannels = m_fifoAudioBus->numberOfChannels();
-
-  for (size_t channelIndex = 0; channelIndex < numberOfChannels;
-       ++channelIndex) {
-    float* destinationData = destination->channel(channelIndex)->mutableData();
-    const float* sourceData = m_fifoAudioBus->channel(channelIndex)->data();
-
-    bool isCopyGood = ((m_readIndex < m_fifoLength) &&
-                       (m_readIndex + part1Length) <= m_fifoLength &&
-                       (part1Length <= destination->length()) &&
-                       (part1Length + part2Length) <= destination->length());
-    ASSERT(isCopyGood);
-    if (!isCopyGood)
-      return;
-
-    memcpy(destinationData, sourceData + m_readIndex,
-           part1Length * sizeof(*sourceData));
-    // Handle wrap around of the FIFO, if needed.
-    if (part2Length)
-      memcpy(destinationData + part1Length, sourceData,
-             part2Length * sizeof(*sourceData));
-  }
-  m_readIndex = updateIndex(m_readIndex, framesToConsume);
-  ASSERT(m_framesInFifo >= framesToConsume);
-  m_framesInFifo -= framesToConsume;
-}
-
-void AudioFIFO::push(const AudioBus* sourceBus) {
-  // Copy the sourceBus into the FIFO buffer.
-
-  bool isGood =
-      sourceBus && (m_framesInFifo + sourceBus->length() <= m_fifoLength);
-  if (!isGood)
-    return;
-
-  size_t sourceLength = sourceBus->length();
-  size_t part1Length;
-  size_t part2Length;
-  findWrapLengths(m_writeIndex, sourceLength, part1Length, part2Length);
-
-  size_t numberOfChannels = m_fifoAudioBus->numberOfChannels();
-
-  for (size_t channelIndex = 0; channelIndex < numberOfChannels;
-       ++channelIndex) {
-    float* destination = m_fifoAudioBus->channel(channelIndex)->mutableData();
-    const float* source = sourceBus->channel(channelIndex)->data();
-
-    bool isCopyGood = ((m_writeIndex < m_fifoLength) &&
-                       (m_writeIndex + part1Length) <= m_fifoLength &&
-                       part2Length < m_fifoLength &&
-                       part1Length + part2Length <= sourceLength);
-    ASSERT(isCopyGood);
-    if (!isCopyGood)
-      return;
-
-    memcpy(destination + m_writeIndex, source,
-           part1Length * sizeof(*destination));
-
-    // Handle wrap around of the FIFO, if needed.
-    if (part2Length)
-      memcpy(destination, source + part1Length,
-             part2Length * sizeof(*destination));
-  }
-
-  m_framesInFifo += sourceLength;
-  ASSERT(m_framesInFifo <= m_fifoLength);
-  m_writeIndex = updateIndex(m_writeIndex, sourceLength);
-}
-
-void AudioFIFO::findWrapLengths(size_t index,
-                                size_t size,
-                                size_t& part1Length,
-                                size_t& part2Length) {
-  SECURITY_DCHECK(index < m_fifoLength && size <= m_fifoLength);
-  if (index < m_fifoLength && size <= m_fifoLength) {
-    if (index + size > m_fifoLength) {
-      // Need to wrap. Figure out the length of each piece.
-      part1Length = m_fifoLength - index;
-      part2Length = size - part1Length;
-    } else {
-      // No wrap needed.
-      part1Length = size;
-      part2Length = 0;
-    }
-  } else {
-    // Invalid values for index or size. Set the part lengths to zero so nothing
-    // is copied.
-    part1Length = 0;
-    part2Length = 0;
-  }
-}
-
-}  // namespace blink