From 6e29b91ae27f7e43079fcf3eb5e3101929e0a877 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Tue, 19 Jul 2022 12:15:27 +0200 Subject: [PATCH] add some comments to sdp_msg.c Related: SYS#5066 Change-Id: I68aa4af5d84eaaa08a567377687b6292cce0ce94 --- src/libmsc/sdp_msg.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/src/libmsc/sdp_msg.c b/src/libmsc/sdp_msg.c index ff8265a33..a76ae5e5f 100644 --- a/src/libmsc/sdp_msg.c +++ b/src/libmsc/sdp_msg.c @@ -163,6 +163,13 @@ struct sdp_audio_codec *sdp_audio_codecs_add_copy(struct sdp_audio_codecs *ac, c codec->fmtp[0] ? codec->fmtp : NULL); } +/* Find or create an entry for the given payload_type number in the given list of codecs. + * If the given payload_type number is already present in ac, return the first matching entry. + * If no such payload_type number is present: a) return NULL if create == false; + * b) If create == true, add a mostly empty codec entry to the end of ac with the given payload_type number, and return + * the created entry. + * If create == true, a NULL return value means that there was no unused entry left in ac to add this payload_type. + */ struct sdp_audio_codec *sdp_audio_codecs_by_payload_type(struct sdp_audio_codecs *ac, unsigned int payload_type, bool create) { @@ -285,6 +292,7 @@ int sdp_parse_attrib(struct sdp_msg *sdp, const char *src) #define A_RECVONLY "recvonly" if (osmo_str_startswith(src, A_RTPMAP)) { + /* "a=rtpmap:3 GSM/8000" */ char *audio_name; unsigned int channels = 1; if (sscanf(src, A_RTPMAP "%u", &payload_type) != 1) @@ -306,6 +314,7 @@ int sdp_parse_attrib(struct sdp_msg *sdp, const char *src) } else if (osmo_str_startswith(src, A_FMTP)) { + /* "a=fmtp:112 octet-align=1;mode-set=0,1,2,3" */ char *fmtp_str; const char *line_end = sdp_msg_line_end(src); if (sscanf(src, A_FMTP "%u", &payload_type) != 1) @@ -327,6 +336,7 @@ int sdp_parse_attrib(struct sdp_msg *sdp, const char *src) } else if (osmo_str_startswith(src, A_PTIME)) { + /* "a=ptime:20" */ if (sscanf(src, A_PTIME "%u", &sdp->ptime) != 1) return -EINVAL; @@ -337,14 +347,17 @@ int sdp_parse_attrib(struct sdp_msg *sdp, const char *src) } else if (osmo_str_startswith(src, A_SENDRECV)) { + /* "a=sendrecv" */ /* TODO? */ } else if (osmo_str_startswith(src, A_SENDONLY)) { + /* "a=sendonly" */ /* TODO? */ } else if (osmo_str_startswith(src, A_RECVONLY)) { + /* "a=recvonly" */ /* TODO? */ }