04ad09d5028a612ada6b3373debe86a1e607da92
[paraslash.git] / write.h
1 /*
2 * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
17 */
18
19 /** \file write.h writer-related structures */
20
21 /** the list of supported writers */
22 enum writer_enum {WRITER_ENUM};
23
24 /**
25 * decbribes one running instance of a writer
26 */
27 struct writer_node {
28 /** points to the writer structure associated with this node */
29 struct writer *writer;
30 /** writer-specific data */
31 void *private_data;
32 /** send that many bytes in one go */
33 int chunk_bytes;
34 struct task task;
35 struct writer_node_group *wng;
36 };
37
38 /** describes one supported writer */
39 struct writer {
40 /**
41 * the init function of the writer
42 *
43 * It must fill in all other function pointers of the given
44 * writer structure.
45 *
46 */
47 void (*init)(struct writer *w);
48 /**
49 *
50 * open one instance of this writer
51 *
52 * This function should perform any work necessary to write the incoming
53 * stream. If To this aim, it may allocate its private data structure and store
54 * a pointer to that structure via the given writer_node paramenter.
55 */
56 int (*open)(struct writer_node *);
57 /**
58 *
59 * write a chunk of audio data
60 *
61 * This is called from the driving application whenever a data block of \a
62 * chunk_bytes is available. It must return the number of bytes consumed from
63 * \a data on success, and negative on errors.
64 *
65 */
66 int (*write)(char *data, size_t nbytes, struct writer_node *);
67 void (*pre_select)(struct sched *s, struct task *t);
68 void (*post_select)(struct sched *s, struct task *t);
69 /**
70 * close one instance of the writer
71 *
72 * This function is assumed to succeed.
73 */
74 void (*close)(struct writer_node *);
75 /**
76 * shutdown the writer
77 *
78 * This is a optional function pointer used for cleaning
79 * up.
80 */
81 void (*shutdown)(struct writer_node *);
82 };
83
84 /**
85 * describes a set of writer nodes that all write the same stream.
86 */
87 struct writer_node_group {
88 /** number of nodes belonging to this group */
89 unsigned num_writers;
90 /** array of pointers to the corresponding writer nodes */
91 struct writer_node *writer_nodes;
92 /** keeps track of how many bytes have been written by each node */
93 int *written;
94 /** the maximum of the chunk_bytes values of the writer nodes in this group */
95 size_t max_chunk_bytes;
96 /** non-zero if end of file was encountered */
97 int *input_eof;
98 int eof;
99 char *buf;
100 size_t *loaded;
101 struct task task;
102 };
103
104 /** loop over each writer node in a writer group */
105 #define FOR_EACH_WRITER_NODE(i, wng) for (i = 0; i < (wng)->num_writers; i++)
106 /** loop over each supported writer */
107 #define FOR_EACH_WRITER(i) for (i = 0; i < NUM_SUPPORTED_WRITERS; i++)
108
109 /** declare the init functions of all supported writers */
110 DECLARE_WRITER_INITS;
111
112 /** array containing the name of each writer */
113 extern const char *writer_names[];
114
115 /** the writer structure for each supported writer */
116 extern struct writer writers[NUM_SUPPORTED_WRITERS];