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package sdp
import (
"strings"
)
// Marshal takes a SDP struct to text
// https://tools.ietf.org/html/rfc4566#section-5
// Session description
// v= (protocol version)
// o= (originator and session identifier)
// s= (session name)
// i=* (session information)
// u=* (URI of description)
// e=* (email address)
// p=* (phone number)
// c=* (connection information -- not required if included in
// all media)
// b=* (zero or more bandwidth information lines)
// One or more time descriptions ("t=" and "r=" lines; see below)
// z=* (time zone adjustments)
// k=* (encryption key)
// a=* (zero or more session attribute lines)
// Zero or more media descriptions
//
// Time description
// t= (time the session is active)
// r=* (zero or more repeat times)
//
// Media description, if present
// m= (media name and transport address)
// i=* (media title)
// c=* (connection information -- optional if included at
// session level)
// b=* (zero or more bandwidth information lines)
// k=* (encryption key)
// a=* (zero or more media attribute lines)
func (s *SessionDescription) Marshal() ([]byte, error) {
m := make(marshaller, 0, 1024)
m.addKeyValue("v=", s.Version.String())
m.addKeyValue("o=", s.Origin.String())
m.addKeyValue("s=", s.SessionName.String())
if s.SessionInformation != nil {
m.addKeyValue("i=", s.SessionInformation.String())
}
if s.URI != nil {
m.addKeyValue("u=", s.URI.String())
}
if s.EmailAddress != nil {
m.addKeyValue("e=", s.EmailAddress.String())
}
if s.PhoneNumber != nil {
m.addKeyValue("p=", s.PhoneNumber.String())
}
if s.ConnectionInformation != nil {
m.addKeyValue("c=", s.ConnectionInformation.String())
}
for _, b := range s.Bandwidth {
m.addKeyValue("b=", b.String())
}
for _, td := range s.TimeDescriptions {
m.addKeyValue("t=", td.Timing.String())
for _, r := range td.RepeatTimes {
m.addKeyValue("r=", r.String())
}
}
if len(s.TimeZones) > 0 {
var b strings.Builder
for i, z := range s.TimeZones {
if i > 0 {
b.WriteString(" ")
}
b.WriteString(z.String())
}
m.addKeyValue("z=", b.String())
}
if s.EncryptionKey != nil {
m.addKeyValue("k=", s.EncryptionKey.String())
}
for _, a := range s.Attributes {
m.addKeyValue("a=", a.String())
}
for _, md := range s.MediaDescriptions {
m.addKeyValue("m=", md.MediaName.String())
if md.MediaTitle != nil {
m.addKeyValue("i=", md.MediaTitle.String())
}
if md.ConnectionInformation != nil {
m.addKeyValue("c=", md.ConnectionInformation.String())
}
for _, b := range md.Bandwidth {
m.addKeyValue("b=", b.String())
}
if md.EncryptionKey != nil {
m.addKeyValue("k=", md.EncryptionKey.String())
}
for _, a := range md.Attributes {
m.addKeyValue("a=", a.String())
}
}
return m.bytes(), nil
}
// marshaller contains state during marshaling.
type marshaller []byte
func (m *marshaller) addKeyValue(key, value string) {
if value == "" {
return
}
*m = append(*m, key...)
*m = append(*m, value...)
*m = append(*m, "\r\n"...)
}
func (m *marshaller) bytes() []byte {
return *m
}
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