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server/vendor/github.com/pion/sdp/v3/media_description.go

@@ -0,0 +1,128 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+package sdp
+
+import (
+	"strconv"
+)
+
+// MediaDescription represents a media type.
+// https://tools.ietf.org/html/rfc4566#section-5.14
+type MediaDescription struct {
+	// m=<media> <port>/<number of ports> <proto> <fmt> ...
+	// https://tools.ietf.org/html/rfc4566#section-5.14
+	MediaName MediaName
+
+	// i=<session description>
+	// https://tools.ietf.org/html/rfc4566#section-5.4
+	MediaTitle *Information
+
+	// c=<nettype> <addrtype> <connection-address>
+	// https://tools.ietf.org/html/rfc4566#section-5.7
+	ConnectionInformation *ConnectionInformation
+
+	// b=<bwtype>:<bandwidth>
+	// https://tools.ietf.org/html/rfc4566#section-5.8
+	Bandwidth []Bandwidth
+
+	// k=<method>
+	// k=<method>:<encryption key>
+	// https://tools.ietf.org/html/rfc4566#section-5.12
+	EncryptionKey *EncryptionKey
+
+	// a=<attribute>
+	// a=<attribute>:<value>
+	// https://tools.ietf.org/html/rfc4566#section-5.13
+	Attributes []Attribute
+}
+
+// Attribute returns the value of an attribute and if it exists
+func (d *MediaDescription) Attribute(key string) (string, bool) {
+	for _, a := range d.Attributes {
+		if a.Key == key {
+			return a.Value, true
+		}
+	}
+	return "", false
+}
+
+// RangedPort supports special format for the media field "m=" port value. If
+// it may be necessary to specify multiple transport ports, the protocol allows
+// to write it as: <port>/<number of ports> where number of ports is a an
+// offsetting range.
+type RangedPort struct {
+	Value int
+	Range *int
+}
+
+func (p *RangedPort) String() string {
+	output := strconv.Itoa(p.Value)
+	if p.Range != nil {
+		output += "/" + strconv.Itoa(*p.Range)
+	}
+	return output
+}
+
+func (p RangedPort) marshalInto(b []byte) []byte {
+	b = strconv.AppendInt(b, int64(p.Value), 10)
+	if p.Range != nil {
+		b = append(b, '/')
+		b = strconv.AppendInt(b, int64(*p.Range), 10)
+	}
+	return b
+}
+
+func (p RangedPort) marshalSize() (size int) {
+	size = lenInt(int64(p.Value))
+	if p.Range != nil {
+		size += 1 + lenInt(int64(*p.Range))
+	}
+
+	return
+}
+
+// MediaName describes the "m=" field storage structure.
+type MediaName struct {
+	Media   string
+	Port    RangedPort
+	Protos  []string
+	Formats []string
+}
+
+func (m MediaName) String() string {
+	return stringFromMarshal(m.marshalInto, m.marshalSize)
+}
+
+func (m MediaName) marshalInto(b []byte) []byte {
+	appendList := func(list []string, sep byte) {
+		for i, p := range list {
+			if i != 0 && i != len(list) {
+				b = append(b, sep)
+			}
+			b = append(b, p...)
+		}
+	}
+
+	b = append(append(b, m.Media...), ' ')
+	b = append(m.Port.marshalInto(b), ' ')
+	appendList(m.Protos, '/')
+	b = append(b, ' ')
+	appendList(m.Formats, ' ')
+	return b
+}
+
+func (m MediaName) marshalSize() (size int) {
+	listSize := func(list []string) {
+		for _, p := range list {
+			size += 1 + len(p)
+		}
+	}
+
+	size = len(m.Media)
+	size += 1 + m.Port.marshalSize()
+	listSize(m.Protos)
+	listSize(m.Formats)
+
+	return size
+}