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);
49 void (*free_config)(void *conf);
51 * Open one instance of this writer.
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.
57 int (*open)(struct writer_node *);
59 * Prepare the fd sets for select.
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
66 int (*pre_select)(struct sched *s, struct writer_node *wn);
67 void (*pre_select_btr)(struct sched *s, struct task *t);
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
77 int (*post_select)(struct sched *s, struct writer_node *wn);
78 void (*post_select_btr)(struct sched *s, struct task *t);
80 * Close one instance of the writer.
82 * This function is assumed to succeed.
84 void (*close)(struct writer_node *);
88 * This is a optional function pointer used for cleaning up.
90 void (*shutdown)(struct writer_node *);
92 btr_command_handler execute;
96 * Describes a set of writer nodes that all write the same stream.
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. */
105 /** Current output buffer. */
107 /** Number of bytes loaded in the output buffer. */
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. */
115 /** Whether the group is open, i.e. wng_open() was called. */
117 /** Max number of bytes written in the previous post_select() call. */
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++)
126 /** Declare the init functions of all supported writers. */
127 DECLARE_WRITER_INITS;
129 /** Array containing the name of each writer. */
130 extern const char *writer_names[];
132 /** The writer structure for each supported writer. */
133 extern struct writer writers[NUM_SUPPORTED_WRITERS];