129 lines
2.9 KiB
Go
129 lines
2.9 KiB
Go
// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
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// SPDX-License-Identifier: MIT
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package sdp
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import (
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"strconv"
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)
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// MediaDescription represents a media type.
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// https://tools.ietf.org/html/rfc4566#section-5.14
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type MediaDescription struct {
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// m=<media> <port>/<number of ports> <proto> <fmt> ...
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// https://tools.ietf.org/html/rfc4566#section-5.14
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MediaName MediaName
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// i=<session description>
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// https://tools.ietf.org/html/rfc4566#section-5.4
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MediaTitle *Information
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// c=<nettype> <addrtype> <connection-address>
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// https://tools.ietf.org/html/rfc4566#section-5.7
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ConnectionInformation *ConnectionInformation
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// b=<bwtype>:<bandwidth>
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// https://tools.ietf.org/html/rfc4566#section-5.8
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Bandwidth []Bandwidth
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// k=<method>
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// k=<method>:<encryption key>
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// https://tools.ietf.org/html/rfc4566#section-5.12
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EncryptionKey *EncryptionKey
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// a=<attribute>
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// a=<attribute>:<value>
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// https://tools.ietf.org/html/rfc4566#section-5.13
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Attributes []Attribute
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}
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// Attribute returns the value of an attribute and if it exists
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func (d *MediaDescription) Attribute(key string) (string, bool) {
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for _, a := range d.Attributes {
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if a.Key == key {
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return a.Value, true
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}
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}
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return "", false
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}
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// RangedPort supports special format for the media field "m=" port value. If
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// it may be necessary to specify multiple transport ports, the protocol allows
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// to write it as: <port>/<number of ports> where number of ports is a an
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// offsetting range.
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type RangedPort struct {
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Value int
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Range *int
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}
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func (p *RangedPort) String() string {
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output := strconv.Itoa(p.Value)
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if p.Range != nil {
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output += "/" + strconv.Itoa(*p.Range)
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}
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return output
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}
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func (p RangedPort) marshalInto(b []byte) []byte {
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b = strconv.AppendInt(b, int64(p.Value), 10)
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if p.Range != nil {
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b = append(b, '/')
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b = strconv.AppendInt(b, int64(*p.Range), 10)
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}
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return b
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}
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func (p RangedPort) marshalSize() (size int) {
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size = lenInt(int64(p.Value))
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if p.Range != nil {
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size += 1 + lenInt(int64(*p.Range))
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}
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return
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}
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// MediaName describes the "m=" field storage structure.
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type MediaName struct {
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Media string
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Port RangedPort
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Protos []string
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Formats []string
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}
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func (m MediaName) String() string {
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return stringFromMarshal(m.marshalInto, m.marshalSize)
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}
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func (m MediaName) marshalInto(b []byte) []byte {
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appendList := func(list []string, sep byte) {
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for i, p := range list {
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if i != 0 && i != len(list) {
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b = append(b, sep)
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}
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b = append(b, p...)
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}
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}
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b = append(append(b, m.Media...), ' ')
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b = append(m.Port.marshalInto(b), ' ')
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appendList(m.Protos, '/')
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b = append(b, ' ')
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appendList(m.Formats, ' ')
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return b
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}
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func (m MediaName) marshalSize() (size int) {
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listSize := func(list []string) {
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for _, p := range list {
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size += 1 + len(p)
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}
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}
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size = len(m.Media)
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size += 1 + m.Port.marshalSize()
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listSize(m.Protos)
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listSize(m.Formats)
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return size
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}
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