Switch audiod over to the buffer tree API.
[paraslash.git] / write.h
1 /*
2 * Copyright (C) 2006-2009 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 /** The number of this writer. */
17 int writer_num;
18 /** Writer-specific data. */
19 void *private_data;
20 /** Pointer to the group this node belongs to. */
21 struct writer_node_group *wng;
22 /** The writer-specific configuration of this node. */
23 void *conf;
24 /** How much of the wng's buffer is already written. */
25 size_t written;
26 struct btr_node *btrn;
27 struct task task;
28 size_t min_iqs;
29 };
30
31 /** Describes one supported writer. */
32 struct writer {
33 /**
34 * The init function of the writer.
35 *
36 * It must fill in all other function pointers of the given
37 * writer structure.
38 */
39 void (*init)(struct writer *w);
40 /**
41 * The command line parser of the writer.
42 *
43 * It should check whether the command line options given by \a options are
44 * valid. On success, it should return a pointer to the writer-specific
45 * configuration data determined by \a options. Note that this might be called
46 * more than once with different values of \a options.
47 */
48 void *(*parse_config)(const char *options);
49 void (*free_config)(void *conf);
50 /**
51 * Open one instance of this writer.
52 *
53 * This function should perform any work necessary to write the incoming
54 * stream. To this aim, it may allocate its private data structure and store
55 * a pointer to that structure via the given writer_node parameter.
56 */
57 int (*open)(struct writer_node *);
58 /**
59 * Prepare the fd sets for select.
60 *
61 * This is called from the writer node group task's pre_select(). It
62 * may use the sched pointer to add any file descriptors or to decrease
63 * the select timeout. It must return positive on success and negative
64 * on errors.
65 */
66 int (*pre_select)(struct sched *s, struct writer_node *wn);
67 void (*pre_select_btr)(struct sched *s, struct task *t);
68 /**
69 * Write audio data.
70 *
71 * Called from the post_select function of the wng task. It must keep
72 * track of the number of bytes consumed from the wng's buffer via
73 * the \p wn->written variable (which may be modified by the wng handling
74 * functions). This function must return positive on success and
75 * negative on errors.
76 */
77 int (*post_select)(struct sched *s, struct writer_node *wn);
78 void (*post_select_btr)(struct sched *s, struct task *t);
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 up.
89 */
90 void (*shutdown)(struct writer_node *);
91 struct ggo_help help;
92 btr_command_handler execute;
93 };
94
95 /**
96 * Describes a set of writer nodes that all write the same stream.
97 */
98 struct writer_node_group {
99 /** Number of nodes belonging to this group. */
100 unsigned num_writers;
101 /** Array of pointers to the corresponding writer nodes. */
102 struct writer_node *writer_nodes;
103 /** Non-zero if an error or end of file was encountered by the feeding task. */
104 int *input_error;
105 /** Current output buffer. */
106 char **bufp;
107 /** Number of bytes loaded in the output buffer. */
108 size_t *loaded;
109 /** Number of audio channels of the current stream. */
110 unsigned int *channels;
111 /** Sample rate of the current stream. */
112 unsigned int *samplerate;
113 /** The task associated to this group. */
114 struct task task;
115 /** Whether the group is open, i.e. wng_open() was called. */
116 int open;
117 /** Max number of bytes written in the previous post_select() call. */
118 int last_written;
119 };
120
121 /** Loop over each writer node in a writer group. */
122 #define FOR_EACH_WRITER_NODE(i, wng) for (i = 0; i < (wng)->num_writers; i++)
123 /** Loop over each supported writer. */
124 #define FOR_EACH_WRITER(i) for (i = 0; i < NUM_SUPPORTED_WRITERS; i++)
125
126 /** Declare the init functions of all supported writers. */
127 DECLARE_WRITER_INITS;
128
129 /** Array containing the name of each writer. */
130 extern const char *writer_names[];
131
132 /** The writer structure for each supported writer. */
133 extern struct writer writers[NUM_SUPPORTED_WRITERS];