kafecho · September 5, 2014 16:47 · Sep 5, 2014
diff --git a/SdpParser.scala b/SdpParser.scala
@@ -0,0 +1,98 @@
+package org.kafecho.learning.parser
+
+import scala.util.parsing.combinator.RegexParsers
+import java.net.URI
+
+sealed trait SdpValue
+
+sealed trait Username
+case class UserLogin(login: String) extends Username
+case object UserIdsNotSupported extends Username
+
+sealed trait Media
+case object Audio extends Media
+case object Video extends Media
+case object Text extends Media
+case object Application extends Media
+
+sealed trait Attribute
+case class BinaryAttribute(value: String) extends Attribute
+case class KeyValueAttribute(key: String, value: String) extends Attribute
+
+case class ProtocolVersion(version: Long) extends SdpValue
+case class Origin(username: Username, sessionId: Long, sessionVersion: Long, netType: String, addrType: String, unicastAddress: Option[String]) extends SdpValue
+case class SessionName(name: String) extends SdpValue
+case class Information(information: String) extends SdpValue
+case class Protocol(protocol: String)
+
+case class MediaField(media: Media, port: Long, protocol: Protocol, payloadType: Long)
+
+/** Prototype parser for the Session Description Protocol.
+  * See http://tools.ietf.org/html/rfc4566.html#page-39
+  * Also see http://www.regular-expressions.info/posixbrackets.html for some help on regexes.
+  */
+class SdpParser extends RegexParsers {
+  def nonWsString: Parser[String] = """\p{Graph}+""".r
+
+  def number: Parser[Long] = """\p{Digit}+""".r ^^ { _.toLong }
+
+  def text: Parser[String] = """\p{Print}+""".r
+
+  def username: Parser[Username] = ("-" | nonWsString) ^^ {
+    case "-" => UserIdsNotSupported
+    case s: String => UserLogin(s)
+  }
+
+  def netType: Parser[String] = "IN"
+
+  def addrType: Parser[String] = "IP4|IP6".r
+
+  def media: Parser[Media] = ("video" | "audio" | "text" | "application") ^^ {
+    case "video" => Video
+    case "audio" => Audio
+    case "text" => Text
+    case "application" => Application
+  }
+
+  val token = """( \x21 | [\x23-\x27]|[\x2A-\x2B]|[\x2D-\x2E]|[\x30-\x39]|[\x41-\x5A]|[\x5E-\x7E])+""".r
+
+  def protocolVersionField: Parser[ProtocolVersion] = "v=" ~ number ^^ { case _ ~ n => ProtocolVersion(n) }
+
+  def originField: Parser[Origin] = ("o=" ~ username ~ number ~ number ~ netType ~ addrType ~ opt(nonWsString)) ^^ {
+    case _ ~ username ~ sessionId ~ sessionVersion ~ netType ~ addrType ~ unicastAddress =>
+    Origin(username, sessionId, sessionVersion, netType, addrType, unicastAddress)
+  }
+
+  def sessionNameField: Parser[SessionName] = ("s=" ~ text) ^^ { case _ ~ text => SessionName(text) }
+
+  def informationField: Parser[Information] = ("i=" ~ text) ^^ { case _ ~ text => Information(text) }
+
+  def uriField : Parser[URI] = ("u=" ~ text) ^^ { case _ ~ s =>  new URI(s)}
+
+  def protocol : Parser[Protocol] = ("""RTP/AVP""" | "udp") ^^ { s => Protocol(s) }
+
+  def mediaField : Parser[MediaField] = ("m=" ~ media ~ number ~ protocol ~ number) ^^ { case _ ~ media ~ port ~ protocol ~ payloadType =>
+  	MediaField(media, port, protocol, payloadType)
+  }
+
+  def keyValueAttribute : Parser[Attribute]= ( token ~ ":" ~ nonWsString ) ^^ { case key ~ ":" ~ value => KeyValueAttribute(key, value)}
+
+  def binaryAttribute: Parser[Attribute]= nonWsString ^^ { s => BinaryAttribute(s)}
+
+  def attributeField : Parser[List[Attribute]] = "a=" ~ rep(keyValueAttribute | binaryAttribute) ^^ { case _ ~ l => l }
+
+  def mediaDescriptions: Parser[Any] = rep(mediaField ~ rep (attributeField))
+}
+
+object SdpParser extends App{
+
+  val src = """
+m=audio 49170 RTP/AVP 0
+m=audio 49170 RTP/AVP 0
+a=rtpmap:99 h263-1998/90000"""
+
+  val parser = new SdpParser
+  val parseResult = parser.parseAll(parser.mediaDescriptions, src)
+  println (parseResult)
+
+}