fix multiple simultaneous writers
[paraslash.git] / write.h
1 /*
2 * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
17 */
18
19 /** \file write.h writer-related structures */
20
21 /** the list of supported writers */
22 enum writer_enum {WRITER_ENUM};
23
24 /**
25 * decbribes one running instance of a writer
26 */
27 struct writer_node {
28 /** points to the writer structure associated with this node */
29 struct writer *writer; /* FIXME: Should better be only the number */
30 /** writer-specific data */
31 void *private_data;
32 /** send that many bytes in one go */
33 int chunk_bytes;
34 /** pointer to the group this node belongs to */
35 struct writer_node_group *wng;
36 /** the writer-specific configuration of this node */
37 void *conf;
38 /** how much of the wng's buffer is already written */
39 size_t written;
40 };
41
42 /** describes one supported writer */
43 struct writer {
44 /**
45 * the init function of the writer
46 *
47 * It must fill in all other function pointers of the given
48 * writer structure.
49 *
50 */
51 void (*init)(struct writer *w);
52 /**
53 *
54 *
55 * the command line parser of the writer
56 *
57 * It should check whether the command line options given by \a options are
58 * valid. On success, it should return a pointer to the writer-specific
59 * configuration data determined by \a options. Note that this might be called
60 * more than once with different values of \a options.
61 *
62 */
63 void * (*parse_config)(char *options);
64 /**
65 *
66 * open one instance of this writer
67 *
68 * This function should perform any work necessary to write the incoming
69 * stream. If To this aim, it may allocate its private data structure and store
70 * a pointer to that structure via the given writer_node paramenter.
71 */
72 int (*open)(struct writer_node *);
73 /**
74 *
75 * write a chunk of audio data
76 *
77 * This is called from the driving application whenever a data block of \a
78 * chunk_bytes is available. It must return the number of bytes consumed from
79 * \a data on success, and negative on errors.
80 *
81 */
82 int (*write)(char *data, size_t nbytes, struct writer_node *);
83 int (*pre_select)(struct sched *s, struct writer_node *wn);
84 int (*post_select)(struct sched *s, struct writer_node *wn);
85 /**
86 * close one instance of the writer
87 *
88 * This function is assumed to succeed.
89 */
90 void (*close)(struct writer_node *);
91 /**
92 * shutdown the writer
93 *
94 * This is a optional function pointer used for cleaning
95 * up.
96 */
97 void (*shutdown)(struct writer_node *);
98 };
99
100 /**
101 * describes a set of writer nodes that all write the same stream.
102 */
103 struct writer_node_group {
104 /** number of nodes belonging to this group */
105 unsigned num_writers;
106 /** array of pointers to the corresponding writer nodes */
107 struct writer_node *writer_nodes;
108 /** the maximum of the chunk_bytes values of the writer nodes in this group */
109 size_t max_chunk_bytes;
110 /** non-zero if end of file was encountered */
111 int *input_eof;
112 int eof;
113 char *buf;
114 unsigned int *channels;
115 unsigned int *samplerate;
116 size_t *loaded;
117 struct task task;
118 };
119
120 /** loop over each writer node in a writer group */
121 #define FOR_EACH_WRITER_NODE(i, wng) for (i = 0; i < (wng)->num_writers; i++)
122 /** loop over each supported writer */
123 #define FOR_EACH_WRITER(i) for (i = 0; i < NUM_SUPPORTED_WRITERS; i++)
124
125 /** declare the init functions of all supported writers */
126 DECLARE_WRITER_INITS;
127
128 /** array containing the name of each writer */
129 extern const char *writer_names[];
130
131 /** the writer structure for each supported writer */
132 extern struct writer writers[NUM_SUPPORTED_WRITERS];