src/chunk.c

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include "config.h"
  21 #include "chunk.h"
  22 #include "audio_format.h"
  23 #include "tag.h"
  24
  25 #include <assert.h>
  26
  27 void
  28 music_chunk_init(struct music_chunk *chunk)
  29 {
  30         chunk->length = 0;
  31         chunk->tag = NULL;
  32         chunk->replay_gain_serial = 0;
  33 }
  34
  35 void
  36 music_chunk_free(struct music_chunk *chunk)
  37 {
  38         if (chunk->tag != NULL)
  39                 tag_free(chunk->tag);
  40 }
  41
  42 #ifndef NDEBUG
  43 bool
  44 music_chunk_check_format(const struct music_chunk *chunk,
  45                          const struct audio_format *audio_format)
  46 {
  47         assert(chunk != NULL);
  48         assert(audio_format != NULL);
  49         assert(audio_format_valid(audio_format));
  50
  51         return chunk->length == 0 ||
  52                 audio_format_equals(&chunk->audio_format, audio_format);
  53 }
  54 #endif
  55
  56 void *
  57 music_chunk_write(struct music_chunk *chunk,
  58                   const struct audio_format *audio_format,
  59                   float data_time, uint16_t bit_rate,
  60                   size_t *max_length_r)
  61 {
  62         const size_t frame_size = audio_format_frame_size(audio_format);
  63         size_t num_frames;
  64
  65         assert(music_chunk_check_format(chunk, audio_format));
  66         assert(chunk->length == 0 || audio_format_valid(&chunk->audio_format));
  67
  68         if (chunk->length == 0) {
  69                 /* if the chunk is empty, nobody has set bitRate and
  70                    times yet */
  71
  72                 chunk->bit_rate = bit_rate;
  73                 chunk->times = data_time;
  74         }
  75
  76         num_frames = (sizeof(chunk->data) - chunk->length) / frame_size;
  77         if (num_frames == 0)
  78                 return NULL;
  79
  80 #ifndef NDEBUG
  81         chunk->audio_format = *audio_format;
  82 #endif
  83
  84         *max_length_r = num_frames * frame_size;
  85         return chunk->data + chunk->length;
  86 }
  87
  88 bool
  89 music_chunk_expand(struct music_chunk *chunk,
  90                    const struct audio_format *audio_format, size_t length)
  91 {
  92         const size_t frame_size = audio_format_frame_size(audio_format);
  93
  94         assert(chunk != NULL);
  95         assert(chunk->length + length <= sizeof(chunk->data));
  96         assert(audio_format_equals(&chunk->audio_format, audio_format));
  97
  98         chunk->length += length;
  99
 100         return chunk->length + frame_size > sizeof(chunk->data);
 101 }