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/*
* Copyright (C) 2003-2010 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_CHUNK_H
#define MPD_CHUNK_H
#include "replay_gain_info.h"
#ifndef NDEBUG
#include "audio_format.h"
#endif
#include <stdbool.h>
#include <stdint.h>
#include <stddef.h>
enum {
CHUNK_SIZE = 4096,
};
struct audio_format;
/**
* A chunk of music data. Its format is defined by the
* music_pipe_append() caller.
*/
struct music_chunk {
/** the next chunk in a linked list */
struct music_chunk *next;
/**
* An optional chunk which should be mixed into this chunk.
* This is used for cross-fading.
*/
struct music_chunk *other;
/** number of bytes stored in this chunk */
uint16_t length;
/** current bit rate of the source file */
uint16_t bit_rate;
/** the time stamp within the song */
float times;
/**
* An optional tag associated with this chunk (and the
* following chunks); appears at song boundaries. The tag
* object is owned by this chunk, and must be freed when this
* chunk is deinitialized in music_chunk_free()
*/
struct tag *tag;
/**
* Replay gain information associated with this chunk.
* Only valid if the serial is not 0.
*/
struct replay_gain_info replay_gain_info;
/**
* A serial number for checking if replay gain info has
* changed since the last chunk. The magic value 0 indicates
* that there is no replay gain info available.
*/
unsigned replay_gain_serial;
/** the data (probably PCM) */
char data[CHUNK_SIZE];
#ifndef NDEBUG
struct audio_format audio_format;
#endif
};
void
music_chunk_init(struct music_chunk *chunk);
void
music_chunk_free(struct music_chunk *chunk);
static inline bool
music_chunk_is_empty(const struct music_chunk *chunk)
{
return chunk->length == 0 && chunk->tag == NULL;
}
#ifndef NDEBUG
/**
* Checks if the audio format if the chunk is equal to the specified
* audio_format.
*/
bool
music_chunk_check_format(const struct music_chunk *chunk,
const struct audio_format *audio_format);
#endif
/**
* Prepares appending to the music chunk. Returns a buffer where you
* may write into. After you are finished, call music_chunk_expand().
*
* @param chunk the music_chunk object
* @param audio_format the audio format for the appended data; must
* stay the same for the life cycle of this chunk
* @param data_time the time within the song
* @param bit_rate the current bit rate of the source file
* @param max_length_r the maximum write length is returned here
* @return a writable buffer, or NULL if the chunk is full
*/
void *
music_chunk_write(struct music_chunk *chunk,
const struct audio_format *audio_format,
float data_time, uint16_t bit_rate,
size_t *max_length_r);
/**
* Increases the length of the chunk after the caller has written to
* the buffer returned by music_chunk_write().
*
* @param chunk the music_chunk object
* @param audio_format the audio format for the appended data; must
* stay the same for the life cycle of this chunk
* @param length the number of bytes which were appended
* @return true if the chunk is full
*/
bool
music_chunk_expand(struct music_chunk *chunk,
const struct audio_format *audio_format, size_t length);
#endif
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