| // 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. |
| |
| #ifndef COBALT_MEDIA_BASE_AUDIO_FIFO_H_ |
| #define COBALT_MEDIA_BASE_AUDIO_FIFO_H_ |
| |
| #include <memory> |
| |
| #include "base/basictypes.h" |
| #include "cobalt/media/base/audio_bus.h" |
| #include "cobalt/media/base/media_export.h" |
| |
| namespace cobalt { |
| namespace media { |
| |
| // First-in first-out container for AudioBus elements. |
| // The maximum number of audio frames in the FIFO is set at construction and |
| // can not be extended dynamically. The allocated memory is utilized as a |
| // ring buffer. |
| // This class is thread-unsafe. |
| class MEDIA_EXPORT AudioFifo { |
| public: |
| // Creates a new AudioFifo and allocates |channels| of length |frames|. |
| AudioFifo(int channels, int frames); |
| virtual ~AudioFifo(); |
| |
| // Pushes all audio channel data from |source| to the FIFO. |
| // Push() will crash if the allocated space is insufficient. |
| void Push(const AudioBus* source); |
| |
| // Consumes |frames_to_consume| audio frames from the FIFO and copies |
| // them to |destination| starting at position |start_frame|. |
| // Consume() will crash if the FIFO does not contain |frames_to_consume| |
| // frames or if there is insufficient space in |destination| to store the |
| // frames. |
| void Consume(AudioBus* destination, int start_frame, int frames_to_consume); |
| |
| // Empties the FIFO without deallocating any memory. |
| void Clear(); |
| |
| // Number of actual audio frames in the FIFO. |
| int frames() const; |
| |
| int max_frames() const { return max_frames_; } |
| |
| private: |
| // The actual FIFO is an audio bus implemented as a ring buffer. |
| std::unique_ptr<AudioBus> audio_bus_; |
| |
| // Maximum number of elements the FIFO can contain. |
| // This value is set by |frames| in the constructor. |
| const int max_frames_; |
| |
| // Number of actual elements in the FIFO. |
| int frames_pushed_; |
| int frames_consumed_; |
| |
| // Current read position. |
| int read_pos_; |
| |
| // Current write position. |
| int write_pos_; |
| |
| DISALLOW_COPY_AND_ASSIGN(AudioFifo); |
| }; |
| |
| } // namespace media |
| } // namespace cobalt |
| |
| #endif // COBALT_MEDIA_BASE_AUDIO_FIFO_H_ |