Extract a useful routine from the softmix bridge technology.
[asterisk/asterisk.git] / bridges / bridge_simple.c
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2007, Digium, Inc.
5  *
6  * Joshua Colp <jcolp@digium.com>
7  *
8  * See http://www.asterisk.org for more information about
9  * the Asterisk project. Please do not directly contact
10  * any of the maintainers of this project for assistance;
11  * the project provides a web site, mailing lists and IRC
12  * channels for your use.
13  *
14  * This program is free software, distributed under the terms of
15  * the GNU General Public License Version 2. See the LICENSE file
16  * at the top of the source tree.
17  */
18
19 /*! \file
20  *
21  * \brief Simple two channel bridging module
22  *
23  * \author Joshua Colp <jcolp@digium.com>
24  *
25  * \ingroup bridges
26  */
27
28 /*** MODULEINFO
29         <support_level>core</support_level>
30  ***/
31
32 #include "asterisk.h"
33
34 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
35
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <sys/types.h>
40 #include <sys/stat.h>
41
42 #include "asterisk/module.h"
43 #include "asterisk/channel.h"
44 #include "asterisk/bridging.h"
45 #include "asterisk/bridging_technology.h"
46 #include "asterisk/frame.h"
47
48 static int simple_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
49 {
50         struct ast_channel *c0 = AST_LIST_FIRST(&bridge->channels)->chan;
51         struct ast_channel *c1 = AST_LIST_LAST(&bridge->channels)->chan;
52
53         /* If this is the first channel we can't make it compatible... unless we make it compatible with itself O.o */
54         if (AST_LIST_FIRST(&bridge->channels) == AST_LIST_LAST(&bridge->channels)) {
55                 return 0;
56         }
57
58         /* See if we need to make these compatible */
59         if ((ast_format_cmp(ast_channel_writeformat(c0), ast_channel_readformat(c1)) == AST_FORMAT_CMP_EQUAL) &&
60                 (ast_format_cmp(ast_channel_readformat(c0), ast_channel_writeformat(c1)) == AST_FORMAT_CMP_EQUAL) &&
61                 (ast_format_cap_identical(ast_channel_nativeformats(c0), ast_channel_nativeformats(c1)))) {
62                 return 0;
63         }
64
65         /* BOOM! We do. */
66         return ast_channel_make_compatible(c0, c1);
67 }
68
69 static int simple_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
70 {
71         return ast_bridge_queue_everyone_else(bridge, bridge_channel, frame);
72 }
73
74 static struct ast_bridge_technology simple_bridge = {
75         .name = "simple_bridge",
76         .capabilities = AST_BRIDGE_CAPABILITY_1TO1MIX,
77         .preference = AST_BRIDGE_PREFERENCE_BASE_1TO1MIX,
78         .join = simple_bridge_join,
79         .write = simple_bridge_write,
80 };
81
82 static int unload_module(void)
83 {
84         ast_format_cap_destroy(simple_bridge.format_capabilities);
85         return ast_bridge_technology_unregister(&simple_bridge);
86 }
87
88 static int load_module(void)
89 {
90         if (!(simple_bridge.format_capabilities = ast_format_cap_alloc())) {
91                 return AST_MODULE_LOAD_DECLINE;
92         }
93         ast_format_cap_add_all_by_type(simple_bridge.format_capabilities, AST_FORMAT_TYPE_AUDIO);
94         ast_format_cap_add_all_by_type(simple_bridge.format_capabilities, AST_FORMAT_TYPE_VIDEO);
95         ast_format_cap_add_all_by_type(simple_bridge.format_capabilities, AST_FORMAT_TYPE_TEXT);
96
97         return ast_bridge_technology_register(&simple_bridge);
98 }
99
100 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Simple two channel bridging module");