freeswitch/libs/sofia-sip/libsofia-sip-ua/sdp/sdp.docs
2008-12-16 18:05:22 +00:00

121 lines
3.1 KiB
C

/* -*- c -*- */
/**@MODULEPAGE "sdp" - SDP Module
@section sdp_meta Module Meta Information
The @b sdp module provides a simple "C" parser interface for SDP [@RFC2327],
<em>Session Description Protocol</em>. The parser also implements support
for IPv6 addresses as per @RFC3266. The @RFC4566 should be supported, but we
have not checked since draft-eitf-mmusic-sdp-new-17 or so.
@CONTACT Pekka Pessi <Pekka.Pessi@nokia.com>
@STATUS @SofiaSIP Core library
@LICENSE LGPL
Contributor(s):
- Pekka Pessi <Pekka.Pessi@nokia.com>
- Jari Selin <Jari.Selin@nokia.com>
@section sdp_parser SDP Parser
SDP parser parses an SDP message and converts it to internally used SDP
structure #sdp_session_t.
Typically, the SDP parser is used as follows:
@code
sdp_parser_t *parser = sdp_parse(home, message, len, 0);
if (!sdp_session(parser)) {
show(sdp_parsing_error(parser));
} else {
sdp_session_t *sdp = sdp_session(parser);
@endcode
Act upon session description, then free the parser:
@code
}
sdp_parser_free(parser);
@endcode
There are various flags indicating what kind of SDP variants the sdp_parse()
accepts. The sanity check run after parsing can be disabled by including
flag #sdp_f_insane. The parser can be used to parse syntactically vague
configuration files when using flag #sdp_f_config. The parser will then
accept * for media, protocol and port, for instance.
@section sdp_printer SDP Printer
SDP printer converts internally used SDP structure #sdp_session_t to the
standard SDP format.
Typically, the SDP printer is used as follows:
@code
char buffer[512];
sdp_printer_t *printer = sdp_print(home, session, buffer, sizeof(buffer), 0);
if (sdp_message(printer)) {
char const *msg = sdp_message(printer);
size_t msgsize = sdp_message_size(printer);
@endcode
At this point, application can use the SDP message contents, e.g., it can
send them to network, and then free the message:
@code
}
else {
show_critical_error(sdp_printing_error(printer));
}
sdp_printer_free(printer);
@endcode
@section sdp_example Example
Examples on using SDP parser can be found from test_sdp.c and soa.c. Here is
an simple example, which decodes an SDP text in @a original, increments the
version number in the origin line, and encodes the SDP description again to
@a buf.
@code
size_t increment_sdp_version(char buf[], size_t bsize,
char const *original, size_t osize)
{
su_home_t home[1] = { SU_HOME_INIT(home) };
sdp_parser_t *parser = sdp_parse(home, original, osize, 0);
sdp_printer_t *printer;
size_t retval = 0;
if (sdp_session(parser)) {
sdp_session_t *sdp = sdp_session(parser);
sdp->sdp_origin->o_version++;
printer = sdp_print(home, sdp, buf, bsize, 0);
if (sdp_message(printer)) {
retval = sdp_message_size(printer);
}
else {
fprintf(stderr, "increment_sdp_version: %s\n",
sdp_printing_error(printer));
}
sdp_printer_free(printer);
}
else {
fprintf(stderr, "increment_sdp_version: %s\n",
sdp_parsing_error(parser));
}
sdp_parser_free(parser);
su_home_deinit(home);
return retval;
}
@endcode
*/