text: /*
   * Audio FIFO
   * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * Audio FIFO Buffer
   */
  
  #ifndef AVUTIL_AUDIO_FIFO_H
  #define AVUTIL_AUDIO_FIFO_H
  
  #include "attributes.h"
  #include "samplefmt.h"
  
  /**
   * @addtogroup lavu_audio
   * @{
   *
   * @defgroup lavu_audiofifo Audio FIFO Buffer
   * @{
   */
  
  /**
   * Context for an Audio FIFO Buffer.
   *
   * - Operates at the sample level rather than the byte level.
   * - Supports multiple channels with either planar or packed sample format.
   * - Automatic reallocation when writing to a full buffer.
   */
  typedef struct AVAudioFifo AVAudioFifo;
  
  /**
   * Free an AVAudioFifo.
   *
   * @param af  AVAudioFifo to free
   */
  void av_audio_fifo_free(AVAudioFifo *af);
  
  /**
   * Allocate an AVAudioFifo.
   *
   * @param sample_fmt  sample format
   * @param channels    number of channels
   * @param nb_samples  initial allocation size, in samples
   * @return            newly allocated AVAudioFifo, or NULL on error
   */
  AVAudioFifo *av_audio_fifo_alloc(enum AVSampleFormat sample_fmt, int channels,
                                   int nb_samples);
  
  /**
   * Reallocate an AVAudioFifo.
   *
   * @param af          AVAudioFifo to reallocate
   * @param nb_samples  new allocation size, in samples
   * @return            0 if OK, or negative AVERROR code on failure
   */
  av_warn_unused_result
  int av_audio_fifo_realloc(AVAudioFifo *af, int nb_samples);
  
  /**
   * Write data to an AVAudioFifo.
   *
   * The AVAudioFifo will be reallocated automatically if the available space
   * is less than nb_samples.
   *
   * @see enum AVSampleFormat
   * The documentation for AVSampleFormat describes the data layout.
   *
   * @param af          AVAudioFifo to write to
   * @param data        audio data plane pointers
   * @param nb_samples  number of samples to write
   * @return            number of samples actually written, or negative AVERROR
   *                    code on failure. If successful, the number of samples
   *                    actually written will always be nb_samples.
   */
  int av_audio_fifo_write(AVAudioFifo *af, void **data, int nb_samples);
  
  /**
   * Peek data from an AVAudioFifo.
   *
   * @see enum AVSampleFormat
   * The documentation for AVSampleFormat describes the data layout.
   *
   * @param af          AVAudioFifo to read from
   * @param data        audio data plane pointers
   * @param nb_samples  number of samples to peek
   * @return            number of samples actually peek, or negative AVERROR code
   *                    on failure. The number of samples actually peek will not
   *                    be greater than nb_samples, and will only be less than
   *                    nb_samples if av_audio_fifo_size is less than nb_samples.
   */
  int av_audio_fifo_peek(AVAudioFifo *af, void **data, int nb_samples);
  
  /**
   * Peek data from an AVAudioFifo.
   *
   * @see enum AVSampleFormat
   * The documentation for AVSampleFormat describes the data layout.
   *
   * @param af          AVAudioFifo to read from
   * @param data        audio data plane pointers
   * @param nb_samples  number of samples to peek
   * @param offset      offset from current read position
   * @return            number of samples actually peek, or negative AVERROR code
   *                    on failure. The number of samples actually peek will not
   *                    be greater than nb_samples, and will only be less than
   *                    nb_samples if av_audio_fifo_size is less than nb_samples.
   */
  int av_audio_fifo_peek_at(AVAudioFifo *af, void **data, int nb_samples, int offset);
  
  /**
   * Read data from an AVAudioFifo.
   *
   * @see enum AVSampleFormat
   * The documentation for AVSampleFormat describes the data layout.
   *
   * @param af          AVAudioFifo to read from
   * @param data        audio data plane pointers
   * @param nb_samples  number of samples to read
   * @return            number of samples actually read, or negative AVERROR code
   *                    on failure. The number of samples actually read will not
   *                    be greater than nb_samples, and will only be less than
   *                    nb_samples if av_audio_fifo_size is less than nb_samples.
   */
  int av_audio_fifo_read(AVAudioFifo *af, void **data, int nb_samples);
  
  /**
   * Drain data from an AVAudioFifo.
   *
   * Removes the data without reading it.
   *
   * @param af          AVAudioFifo to drain
   * @param nb_samples  number of samples to drain
   * @return            0 if OK, or negative AVERROR code on failure
   */
  int av_audio_fifo_drain(AVAudioFifo *af, int nb_samples);
  
  /**
   * Reset the AVAudioFifo buffer.
   *
   * This empties all data in the buffer.
   *
   * @param af  AVAudioFifo to reset
   */
  void av_audio_fifo_reset(AVAudioFifo *af);
  
  /**
   * Get the current number of samples in the AVAudioFifo available for reading.
   *
   * @param af  the AVAudioFifo to query
   * @return    number of samples available for reading
   */
  int av_audio_fifo_size(AVAudioFifo *af);
  
  /**
   * Get the current number of samples in the AVAudioFifo available for writing.
   *
   * @param af  the AVAudioFifo to query
   * @return    number of samples available for writing
   */
  int av_audio_fifo_space(AVAudioFifo *af);
  
  /**
   * @}
   * @}
   */
  
  #endif /* AVUTIL_AUDIO_FIFO_H */
  