/* * 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; /** * The current mix ratio for cross-fading: 1.0 means play 100% * of this chunk, 0.0 means play 100% of the "other" chunk. */ float mix_ratio; /** 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