2 * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file write.h Writer-related structures. */
9 /** The list of supported writers. */
10 enum writer_enum {WRITER_ENUM};
13 * Describes one running instance of a writer.
16 /** The number of this writer. */
18 /** Writer-specific data. */
20 /** Pointer to the group this node belongs to. */
21 struct writer_node_group *wng;
22 /** The writer-specific configuration of this node. */
24 /** How much of the wng's buffer is already written. */
26 struct btr_node *btrn;
31 /** Describes one supported writer. */
34 * The init function of the writer.
36 * It must fill in all other function pointers of the given
39 void (*init)(struct writer *w);
41 * The command line parser of the writer.
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.
48 void *(*parse_config)(const char *options);
50 * Open one instance of this writer.
52 * This function should perform any work necessary to write the incoming
53 * stream. To this aim, it may allocate its private data structure and store
54 * a pointer to that structure via the given writer_node parameter.
56 int (*open)(struct writer_node *);
58 * Prepare the fd sets for select.
60 * This is called from the writer node group task's pre_select(). It
61 * may use the sched pointer to add any file descriptors or to decrease
62 * the select timeout. It must return positive on success and negative
65 int (*pre_select)(struct sched *s, struct writer_node *wn);
66 void (*pre_select_btr)(struct sched *s, struct task *t);
70 * Called from the post_select function of the wng task. It must keep
71 * track of the number of bytes consumed from the wng's buffer via
72 * the \p wn->written variable (which may be modified by the wng handling
73 * functions). This function must return positive on success and
76 int (*post_select)(struct sched *s, struct writer_node *wn);
77 void (*post_select_btr)(struct sched *s, struct task *t);
79 * Close one instance of the writer.
81 * This function is assumed to succeed.
83 void (*close)(struct writer_node *);
87 * This is a optional function pointer used for cleaning up.
89 void (*shutdown)(struct writer_node *);
91 btr_command_handler execute;
95 * Describes a set of writer nodes that all write the same stream.
97 struct writer_node_group {
98 /** Number of nodes belonging to this group. */
100 /** Array of pointers to the corresponding writer nodes. */
101 struct writer_node *writer_nodes;
102 /** Non-zero if an error or end of file was encountered by the feeding task. */
104 /** Current output buffer. */
106 /** Number of bytes loaded in the output buffer. */
108 /** Number of audio channels of the current stream. */
109 unsigned int *channels;
110 /** Sample rate of the current stream. */
111 unsigned int *samplerate;
112 /** The task associated to this group. */
114 /** Whether the group is open, i.e. wng_open() was called. */
116 /** Max number of bytes written in the previous post_select() call. */
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++)
125 /** Declare the init functions of all supported writers. */
126 DECLARE_WRITER_INITS;
128 /** Array containing the name of each writer. */
129 extern const char *writer_names[];
131 /** The writer structure for each supported writer. */
132 extern struct writer writers[NUM_SUPPORTED_WRITERS];