| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "media/base/audio_pull_fifo.h" |
| |
| #include <algorithm> |
| |
| #include "base/logging.h" |
| #include "media/base/audio_bus.h" |
| |
| namespace media { |
| |
| AudioPullFifo::AudioPullFifo(int channels, int frames, const ReadCB& read_cb) |
| : read_cb_(read_cb), |
| fifo_(AudioBus::Create(channels, frames)), |
| fifo_index_(frames) {} |
| |
| AudioPullFifo::~AudioPullFifo() = default; |
| |
| void AudioPullFifo::Consume(AudioBus* destination, int frames_to_consume) { |
| DCHECK_LE(frames_to_consume, destination->frames()); |
| |
| int remaining_frames_to_provide = frames_to_consume; |
| |
| // Try to fulfill the request using what's available in the FIFO. |
| int frames_read = ReadFromFifo(destination, remaining_frames_to_provide, 0); |
| int write_pos = frames_read; |
| remaining_frames_to_provide -= frames_read; |
| |
| // Get the remaining audio frames from the producer using the callback. |
| while (remaining_frames_to_provide > 0) { |
| DCHECK_EQ(fifo_index_, fifo_->frames()); |
| fifo_index_ = 0; |
| |
| // Fill up the FIFO by acquiring audio data from the producer. |
| read_cb_.Run(write_pos, fifo_.get()); |
| |
| // Try to fulfill the request using what's available in the FIFO. |
| frames_read = |
| ReadFromFifo(destination, remaining_frames_to_provide, write_pos); |
| write_pos += frames_read; |
| remaining_frames_to_provide -= frames_read; |
| } |
| } |
| |
| void AudioPullFifo::Clear() { fifo_index_ = fifo_->frames(); } |
| |
| int AudioPullFifo::SizeInFrames() const { |
| return fifo_->frames(); |
| } |
| |
| int AudioPullFifo::ReadFromFifo(AudioBus* destination, |
| int frames_to_provide, |
| int write_pos) { |
| int frames = std::min(frames_to_provide, fifo_->frames() - fifo_index_); |
| if (frames <= 0) |
| return 0; |
| |
| for (int ch = 0; ch < fifo_->channels(); ++ch) { |
| const float* src = fifo_->channel(ch) + fifo_index_; |
| float* dest = destination->channel(ch) + write_pos; |
| memcpy(dest, src, frames * sizeof(*src)); |
| } |
| |
| fifo_index_ += frames; |
| return frames; |
| } |
| |
| } // namespace media |