call_callback(): Fix a shm leak in afs.c.
[paraslash.git] / write.h
1 /*
2 * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file write.h writer-related structures */
8
9 /** the list of supported writers */
10 enum writer_enum {WRITER_ENUM};
11
12 /**
13 * Describes one running instance of a writer.
14 */
15 struct writer_node {
16 /** points to the writer structure associated with this node */
17 struct writer *writer; /* FIXME: Should better be only the number */
18 /** writer-specific data */
19 void *private_data;
20 /** send that many bytes in one go */
21 int chunk_bytes;
22 /** pointer to the group this node belongs to */
23 struct writer_node_group *wng;
24 /** the writer-specific configuration of this node */
25 void *conf;
26 /** how much of the wng's buffer is already written */
27 size_t written;
28 };
29
30 /** describes one supported writer */
31 struct writer {
32 /**
33 * the init function of the writer
34 *
35 * It must fill in all other function pointers of the given
36 * writer structure.
37 *
38 */
39 void (*init)(struct writer *w);
40 /**
41 *
42 *
43 * the command line parser of the writer
44 *
45 * It should check whether the command line options given by \a options are
46 * valid. On success, it should return a pointer to the writer-specific
47 * configuration data determined by \a options. Note that this might be called
48 * more than once with different values of \a options.
49 *
50 */
51 void * (*parse_config)(const char *options);
52 /**
53 *
54 * open one instance of this writer
55 *
56 * This function should perform any work necessary to write the incoming
57 * stream. If To this aim, it may allocate its private data structure and store
58 * a pointer to that structure via the given writer_node parameter.
59 */
60 int (*open)(struct writer_node *);
61 /**
62 *
63 * write a chunk of audio data
64 *
65 * This is called from the writer node group task's pre_select(). It
66 * may use the sched pointer to add any file descriptors or to decrease
67 * the select timeout. It must return positive on success and negative
68 * on errors.
69 */
70 int (*pre_select)(struct sched *s, struct writer_node *wn);
71 /**
72 * Called from the post_select function of the wng task. It must keep
73 * track of the number of bytes consumed from the wng's buffer via
74 * the wn->written variable (which may be modified by the wng handling
75 * functions). This function must return positive on success and
76 * negative on errors.
77 */
78 int (*post_select)(struct sched *s, struct writer_node *wn);
79 /**
80 * close one instance of the writer
81 *
82 * This function is assumed to succeed.
83 */
84 void (*close)(struct writer_node *);
85 /**
86 * shutdown the writer
87 *
88 * This is a optional function pointer used for cleaning
89 * up.
90 */
91 void (*shutdown)(struct writer_node *);
92 };
93
94 /**
95 * describes a set of writer nodes that all write the same stream.
96 */
97 struct writer_node_group {
98 /** number of nodes belonging to this group */
99 unsigned num_writers;
100 /** array of pointers to the corresponding writer nodes */
101 struct writer_node *writer_nodes;
102 /** the maximum of the chunk_bytes values of the writer nodes in this group */
103 size_t max_chunk_bytes;
104 /** Non-zero if an error or end of file was encountered by the feeding task. */
105 int *input_error;
106 /** current output buffer */
107 char *buf;
108 /** number of bytes loaded in the output buffer */
109 size_t *loaded;
110 /** number of audio channels of the current stream */
111 unsigned int *channels;
112 /** sample rate of the current stream */
113 unsigned int *samplerate;
114 /** the task associated to this group */
115 struct task task;
116 /** Whether the group is open, i.e. wng_open() was called. */
117 int open;
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];