sdpparser.java

基于MJSIP的j2me客户端

/*
 * Copyright (C) 2005 Luca Veltri - University of Parma - Italy
 * 
 * This file is part of MjSip (http://www.mjsip.org)
 * 
 * MjSip is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * MjSip is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with MjSip; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * Author(s):
 * Luca Veltri ([e-mail])
 */

package org.zoolu.sdp;


import org.zoolu.sdp.*;
import org.zoolu.tools.Parser;
import java.util.Vector;


/** Class SdpParser extends class Parser for parsing of SDP strings.
 */
class SdpParser extends Parser
{  
   /** Creates a SdpParser based on String <i>s</i> */ 
   public SdpParser(String s)
   {  super(s);
   }

   /** Creates a SdpParser based on String <i>s</i> and starting from position <i>i</i> */ 
   public SdpParser(String s, int i)
   {  super(s,i);
   }
   
   /** Returns the SdpField at the current position.
    *  The SDP value terminates with the end of the String or with the first CR or LF char.
    *  <p> Returns null if no SdpField is recognized. */
   /*public SdpField parseSdpField()
   {  Parser par=new Parser(str,index);
      while (par.length()>1 && par.charAt(1)!='=') par.goToNextLine();
      if (!par.hasMore()) return null;
      char type=par.getChar();
      par.skipChar();
      String value=par.skipChar().getLine();
      if (value==null) return null;
      index=par.getPos();
      // for DEBUG
      //System.out.println("DEBUG: "+type+"="+value);
      return new SdpField(type,value);
   }*/
   
   /** Returns the first SdpField.
    *  The SDP value terminates with the end of the String or with the first CR or LF char.
    *  @return the first SdpField, or null if no SdpField is recognized. */
   public SdpField parseSdpField()
   {  int begin=index;
      while (begin>=0 && begin<str.length()-1 && str.charAt(begin+1)!='=') begin=str.indexOf("\n",begin);  
      if (begin<0) return null;
      char type=str.charAt(begin);
      begin+=2;
      int end=str.length();
      int CR=str.indexOf('\r',begin);
      if (CR>0 && CR<end) end=CR;
      int LF=str.indexOf('\n',begin);
      if (LF>0 && LF<end) end=LF;
      String value=str.substring(begin,end).trim();
      if (value==null) return null;
      setPos(end);
      goToNextLine();
      // for DEBUG
      //System.out.println("DEBUG: "+type+"="+value);
      return new SdpField(type,value);
   }
   
   
   /** Returns the first SdpField of type <i>type</i>.
    *  The SDP value terminates with the end of the String or with the first CR or LF char.
    *  @return the first SdpField, or null if no <i>type</i> SdpField is found. */
   public SdpField parseSdpField(char type)
   {  int begin=0;
      if (!str.startsWith(type+"=",index))
      {  begin=str.indexOf("\n"+type+"=",index);
         //if (begin<0) begin=str.indexOf("\r"+type+"=",index);
         if (begin<0)
         {  // return null if no type SdpField has been found
            return null;
         }
         index=begin+1;
      }
      return parseSdpField(); 
   }  
   
   /** Returns the first OriginField.
    *  @return the first OriginField, or null if no OriginField is found. */
   public OriginField parseOriginField()
   {  SdpField sf=parseSdpField('o');
      if (sf!=null) return new OriginField(sf); else return null;
   }
    
   /** Returns the first MediaField.
    *  @return the first MediaField, or null if no MediaField is found. */
   public MediaField parseMediaField()
   {  SdpField sf=parseSdpField('m');
      if (sf!=null) return new MediaField(sf); else return null;
   }

   /** Returns the first ConnectionField.
    *  @return the first ConnectionField, or null if no ConnectionField is found. */
   public ConnectionField parseConnectionField()
   {  SdpField sf=parseSdpField('c');
      if (sf!=null) return new ConnectionField(sf); else return null;
   }

   /** Returns the first SessionNameField.
    *  @return the first SessionNameField, or null if no SessionNameField is found. */
   public SessionNameField parseSessionNameField()
   {  SdpField sf=parseSdpField('s');
      if (sf!=null) return new SessionNameField(sf); else return null;
   }

   /** Returns the first TimeField.
    *  @return the first TimeField, or null if no TimeField is found. */
   public TimeField parseTimeField()
   {  SdpField sf=parseSdpField('t');
      if (sf!=null) return new TimeField(sf); else return null;
   }

   /** Returns the first AttributeField.
    *  @return the first AttributeField, or null if no AttributeField is found. */
   public AttributeField parseAttributeField()
   {  SdpField sf=parseSdpField('a');
      if (sf!=null) return new AttributeField(sf); else return null;
   }

   /** Returns the first MediaDescriptor.
    *  @return the first MediaDescriptor, or null if no MediaDescriptor is found. */
   public MediaDescriptor parseMediaDescriptor()
   {  MediaField m=parseMediaField();
      if (m==null) return null;
      int begin=index;
      int end=str.indexOf("\nm",begin);
      if (end<0) end=str.length(); else end++;
      index=end;
      SdpParser par=new SdpParser(str.substring(begin,end));
      ConnectionField c=par.parseConnectionField();
      Vector av=new Vector();
      AttributeField a=par.parseAttributeField();
      while (a!=null)
      {  av.addElement(a);
         a=par.parseAttributeField();
      }
      return new MediaDescriptor(m,c,av);
   }

}