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;
30 /** Describes one supported writer. */
33 * The init function of the writer.
35 * It must fill in all other function pointers of the given
38 void (*init)(struct writer *w);
40 * The command line parser of the writer.
42 * It should check whether the command line options given by \a options are
43 * valid. On success, it should return a pointer to the writer-specific
44 * configuration data determined by \a options. Note that this might be called
45 * more than once with different values of \a options.
47 void *(*parse_config)(const char *options);
49 * Open one instance of this writer.
51 * This function should perform any work necessary to write the incoming
52 * stream. To this aim, it may allocate its private data structure and store
53 * a pointer to that structure via the given writer_node parameter.
55 int (*open)(struct writer_node *);
57 * Prepare the fd sets for select.
59 * This is called from the writer node group task's pre_select(). It
60 * may use the sched pointer to add any file descriptors or to decrease
61 * the select timeout. It must return positive on success and negative
64 int (*pre_select)(struct sched *s, struct writer_node *wn);
65 void (*pre_select_btr)(struct sched *s, struct task *t);
69 * Called from the post_select function of the wng task. It must keep
70 * track of the number of bytes consumed from the wng's buffer via
71 * the \p wn->written variable (which may be modified by the wng handling
72 * functions). This function must return positive on success and
75 int (*post_select)(struct sched *s, struct writer_node *wn);
76 void (*post_select_btr)(struct sched *s, struct task *t);
78 * Close one instance of the writer.
80 * This function is assumed to succeed.
82 void (*close)(struct writer_node *);
86 * This is a optional function pointer used for cleaning up.
88 void (*shutdown)(struct writer_node *);
90 btr_command_handler execute;
94 * Describes a set of writer nodes that all write the same stream.
96 struct writer_node_group {
97 /** Number of nodes belonging to this group. */
99 /** Array of pointers to the corresponding writer nodes. */
100 struct writer_node *writer_nodes;
101 /** Non-zero if an error or end of file was encountered by the feeding task. */
103 /** Current output buffer. */
105 /** Number of bytes loaded in the output buffer. */
107 /** Number of audio channels of the current stream. */
108 unsigned int *channels;
109 /** Sample rate of the current stream. */
110 unsigned int *samplerate;
111 /** The task associated to this group. */
113 /** Whether the group is open, i.e. wng_open() was called. */
115 /** Max number of bytes written in the previous post_select() call. */
119 /** Loop over each writer node in a writer group. */
120 #define FOR_EACH_WRITER_NODE(i, wng) for (i = 0; i < (wng)->num_writers; i++)
121 /** Loop over each supported writer. */
122 #define FOR_EACH_WRITER(i) for (i = 0; i < NUM_SUPPORTED_WRITERS; i++)
124 /** Declare the init functions of all supported writers. */
125 DECLARE_WRITER_INITS;
127 /** Array containing the name of each writer. */
128 extern const char *writer_names[];
130 /** The writer structure for each supported writer. */
131 extern struct writer writers[NUM_SUPPORTED_WRITERS];