aboutsummaryrefslogtreecommitdiffstats
path: root/src/MusicChunk.hxx
blob: a9b4c3cfdafdbe34f6edc72896e6166ff039d269 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/*
 * Copyright (C) 2003-2013 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_MUSIC_CHUNK_HXX
#define MPD_MUSIC_CHUNK_HXX

#include "ReplayGainInfo.hxx"

#ifndef NDEBUG
#include "AudioFormat.hxx"
#endif

#include <stdint.h>
#include <stddef.h>

static constexpr size_t CHUNK_SIZE = 4096;

struct AudioFormat;
struct Tag;

/**
 * A chunk of music data.  Its format is defined by the
 * MusicPipe::Push() 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.
	 */
	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
	AudioFormat audio_format;
#endif

	music_chunk()
		:other(nullptr),
		 length(0),
		 tag(nullptr),
		 replay_gain_serial(0) {}

	~music_chunk();

	bool IsEmpty() const {
		return length == 0 && tag == nullptr;
	}

#ifndef NDEBUG
	/**
	 * Checks if the audio format if the chunk is equal to the
	 * specified audio_format.
	 */
	gcc_pure
	bool CheckFormat(AudioFormat audio_format) const;
#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 nullptr if the chunk is full
	 */
	void *Write(AudioFormat af,
		    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 Expand(AudioFormat af, size_t length);
};

#endif