headerpacket.java

来自「java语言开发的P2P流媒体系统」· Java 代码 · 共 125 行

/* 
 * P2P-Radio - Peer to peer streaming system
 * Project homepage: http://p2p-radio.sourceforge.net/
 * Copyright (C) 2003-2004 Michael Kaufmann <[e-mail]>
 * 
 * ---------------------------------------------------------------------------
 * This program 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.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * ---------------------------------------------------------------------------
 */

package p2pradio.packets;

public class HeaderPacket extends MetaStreamPacket
{	
	// Der Header wird nicht noch extra in einem
	// eigenen Array gespeichert
	private int headerOffset;
	private int headerLength;
	
	public HeaderPacket(long seqNr, long timeStamp, byte header[])
	{
		this(new byte[getMaxLength() + header.length], seqNr, timeStamp, header, header.length);
	}
	
	public HeaderPacket(byte content[], long seqNr, long timeStamp, byte[] header)
	{
		this(content, seqNr, timeStamp, header, header.length);
	}
	
	public HeaderPacket(long seqNr, long timeStamp, byte header[], int headerLength)
	{
		this(new byte[getMaxLength() + headerLength], seqNr, timeStamp, header, headerLength);
	}
	
	public HeaderPacket(byte content[], long seqNr, long timeStamp, byte[] header, int headerLength)
	{
		this(content, seqNr, timeStamp, header, 0, headerLength);
	}
	
	public HeaderPacket(long seqNr, long timeStamp, byte header[], int headerOffset, int headerLength)
	{
		this(new byte[getMaxLength() + headerLength], seqNr, timeStamp, header, headerOffset, headerLength);
	}

	protected HeaderPacket(byte content[], long seqNr, long timeStamp, byte[] header, int headerOffset, int headerLength)
	{
		super(Packet.HEADER, content, seqNr, timeStamp);
		
		// L鋘ge des Headers speichern
		writeInt(headerLength);
		
		this.headerOffset = offset;
		this.headerLength = headerLength;
		
		checkBytesLeft(headerLength);
		
		// Header kopieren
		System.arraycopy(header, headerOffset, content, offset, headerLength);
		offset += headerLength;
	}
	
	protected HeaderPacket(byte content[], int contentLength)
	{
		super(content, contentLength);
		
		// L鋘ge des Headers lesen
		int length = readInt();
		
		checkBytesLeft(length);
		
		headerOffset = offset;
		headerLength = length;
		
		offset += length;
	}
	
	// Die Methode getMaxLength() gibt hier nur eine
	// Mindestl鋘ge zur點k
	// Sie ist "public", weil sie von Source.java gebraucht wird
	public static int getMaxLength()
	{
		return StreamPacket.getMaxLength() + 4;
	}
	
	protected String getTypeString()
	{
		return "Header"; //$NON-NLS-1$
	}
	
	public byte[] getHeader()
	{
		return content;
	}
	
	public int getHeaderOffset()
	{
		return headerOffset;
	}
	
	public int getHeaderLength()
	{
		return headerLength;
	}
	
	public byte[] createDataArray()
	{
		byte[] header = new byte[headerLength];
		System.arraycopy(content, headerOffset, header, 0, headerLength);
		
		return header;
	}
}