| /* |
| * Copyright 2017 The Chromium Authors. 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. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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 "config.h" |
| |
| #if ENABLE(WEB_AUDIO) |
| #include "PushPullFIFO.h" |
| |
| #include "AudioBus.h" |
| |
| namespace WebCore { |
| |
| PushPullFIFO::PushPullFIFO(unsigned numberOfChannels, size_t fifoLength) |
| : m_fifoLength(fifoLength) |
| { |
| ASSERT(m_fifoLength <= maxFIFOLength); |
| m_fifoBus = AudioBus::create(numberOfChannels, m_fifoLength); |
| } |
| |
| PushPullFIFO::~PushPullFIFO() = default; |
| |
| // Push the data from |inputBus| to FIFO. The size of push is determined by |
| // the length of |inputBus|. |
| void PushPullFIFO::push(const AudioBus* inputBus) |
| { |
| ASSERT(inputBus); |
| ASSERT(inputBus->length() <= m_fifoLength); |
| ASSERT(m_indexWrite < m_fifoLength); |
| |
| const size_t inputBusLength = inputBus->length(); |
| const size_t remainder = m_fifoLength - m_indexWrite; |
| |
| for (unsigned i = 0; i < m_fifoBus->numberOfChannels(); ++i) { |
| float* fifoBusChannel = m_fifoBus->channel(i)->mutableData(); |
| const float* inputBusChannel = inputBus->channel(i)->data(); |
| if (remainder >= inputBusLength) { |
| // The remainder is big enough for the input data. |
| memcpy(fifoBusChannel + m_indexWrite, inputBusChannel, inputBusLength * sizeof(*fifoBusChannel)); |
| } else { |
| // The input data overflows the remainder size. Wrap around the index. |
| memcpy(fifoBusChannel + m_indexWrite, inputBusChannel, remainder * sizeof(*fifoBusChannel)); |
| memcpy(fifoBusChannel, inputBusChannel + remainder, (inputBusLength - remainder) * sizeof(*fifoBusChannel)); |
| } |
| } |
| |
| // Update the write index; wrap it around if necessary. |
| m_indexWrite = (m_indexWrite + inputBusLength) % m_fifoLength; |
| |
| // In case of overflow, move the |indexRead| to the updated |indexWrite| to |
| // avoid reading overwritten frames by the next pull. |
| if (inputBusLength > m_fifoLength - m_framesAvailable) |
| m_indexRead = m_indexWrite; |
| |
| // Update the number of frames available in FIFO. |
| m_framesAvailable = std::min(m_framesAvailable + inputBusLength, m_fifoLength); |
| ASSERT(((m_indexRead + m_framesAvailable) % m_fifoLength) == m_indexWrite); |
| } |
| |
| // Pull the data out of FIFO to |outputBus|. If remaining frame in the FIFO |
| // is less than the frames to pull, provides remaining frame plus the silence. |
| size_t PushPullFIFO::pull(AudioBus* outputBus, size_t framesRequested) |
| { |
| ASSERT(outputBus); |
| ASSERT(framesRequested <= outputBus->length()); |
| ASSERT(framesRequested <= m_fifoLength); |
| ASSERT(m_indexRead < m_fifoLength); |
| |
| const size_t remainder = m_fifoLength - m_indexRead; |
| const size_t framesToFill = std::min(m_framesAvailable, framesRequested); |
| |
| for (unsigned i = 0; i < m_fifoBus->numberOfChannels(); ++i) { |
| const float* fifoBusChannel = m_fifoBus->channel(i)->data(); |
| float* outputBusChannel = outputBus->channel(i)->mutableData(); |
| |
| // Fill up the output bus with the available frames first. |
| if (remainder >= framesToFill) { |
| // The remainder is big enough for the frames to pull. |
| memcpy(outputBusChannel, fifoBusChannel + m_indexRead, framesToFill * sizeof(*fifoBusChannel)); |
| } else { |
| // The frames to pull is bigger than the remainder size. |
| // Wrap around the index. |
| memcpy(outputBusChannel, fifoBusChannel + m_indexRead, remainder * sizeof(*fifoBusChannel)); |
| memcpy(outputBusChannel + remainder, fifoBusChannel, (framesToFill - remainder) * sizeof(*fifoBusChannel)); |
| } |
| |
| // The frames available was not enough to fulfill the requested frames. Fill |
| // the rest of the channel with silence. |
| if (framesRequested > framesToFill) |
| memset(outputBusChannel + framesToFill, 0, (framesRequested - framesToFill) * sizeof(*outputBusChannel)); |
| } |
| |
| // Update the read index; wrap it around if necessary. |
| m_indexRead = (m_indexRead + framesToFill) % m_fifoLength; |
| |
| // In case of underflow, move the |indexWrite| to the updated |indexRead|. |
| if (framesRequested > framesToFill) |
| m_indexWrite = m_indexRead; |
| |
| // Update the number of frames in FIFO. |
| m_framesAvailable -= framesToFill; |
| ASSERT(((m_indexRead + m_framesAvailable) % m_fifoLength) == m_indexWrite); |
| |
| // |framesRequested > m_framesAvailable| means the frames in FIFO is not |
| // enough to fulfill the requested frames from the audio device. |
| return framesRequested > m_framesAvailable ? framesRequested - m_framesAvailable : 0; |
| } |
| |
| unsigned PushPullFIFO::numberOfChannels() const |
| { |
| return m_fifoBus->numberOfChannels(); |
| } |
| |
| } // namespace WebCore |
| |
| #endif // ENABLE(WEB_AUDIO) |