/*
  * This file is part of "The Java Telnet Application".
  *
  * (c) Matthias L. Jugel, Marcus Meißner 1996-2002. All Rights Reserved.
  * The file was changed by Radek Polak to work as midlet in MIDP 1.0
  *
  * Please visit http://javatelnet.org/ for updates and contact.
  *
  * --LICENSE NOTICE--
  * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
  * --LICENSE NOTICE--
  */
 
 package ssh;
 
 abstract class SshPacket {
   public SshPacket() { /* nothing */
   }
 
   // Data management
   protected byte[] byteArray = new byte[0];
   protected int offset;
   private boolean finished = false;
 
   public byte[] getData() {
     return byteArray;
   }
 
   public void putData(byte[] data) {
     byteArray = data;
     offset = 0;
     finished = true;
   }
 
   public boolean isFinished() {
     return finished;
   }
 
   abstract public byte[] addPayload(byte[] buff);
 
 
   // Type
   private byte packet_type;
 
   public byte getType() {
     return packet_type;
   }
 
   public void setType(byte ntype) {
     packet_type = ntype;
   }
 
   public abstract void putMpInt(BigInteger bi);
 
   public int getInt32() {
     short d0 = byteArray[offset++];
     short d1 = byteArray[offset++];
     short d2 = byteArray[offset++];
     short d3 = byteArray[offset++];
 
     if (d0 < 0) d0 = (short) (256 + d0);
     if (d1 < 0) d1 = (short) (256 + d1);
     if (d2 < 0) d2 = (short) (256 + d2);
     if (d3 < 0) d3 = (short) (256 + d3);
 
     return (d0 << 24) + (d1 << 16) + (d2 << 8) + d3;
   }
 
   public int getInt16() {
     short d0 = byteArray[offset++];
     short d1 = byteArray[offset++];
 
     if (d0 < 0) d0 = (short) (256 + d0);
     if (d1 < 0) d1 = (short) (256 + d1);
 
     return (d0 << 8) + d1;
   }
 
   public String getString() {
     int length = getInt32();
 
     String str = "";
     for (int i = 0; i < length; i++) {
       if (byteArray[offset] >= 0)
         str += (char) (byteArray[offset++]);
       else
         str += (char) (256 + byteArray[offset++]);
     }
     return str;
   }
 
   public byte getByte() {
     return byteArray[offset++];
   }
 
   public byte[] getBytes(int cnt) {
     byte[] bytes = new byte[cnt];
 
     System.arraycopy(byteArray, offset, bytes, 0, cnt);
     offset += cnt;
     return bytes;
   }
 
   private void grow(int howmuch) {
     byte[] value = new byte[byteArray.length + howmuch];
     System.arraycopy(byteArray, 0, value, 0, byteArray.length);
     byteArray = value;
   }
 
   public void putInt16(int xint) {
     int boffset = byteArray.length;
     grow(2);
     byteArray[boffset + 1] = (byte) ((xint) & 0xff);
     byteArray[boffset] = (byte) ((xint >> 8) & 0xff);
   }
 
   public void putInt32(int xint) {
     int boffset = byteArray.length;
     grow(4);
     byteArray[boffset + 3] = (byte) ((xint) & 0xff);
     byteArray[boffset + 2] = (byte) ((xint >> 8) & 0xff);
     byteArray[boffset + 1] = (byte) ((xint >> 16) & 0xff);
     byteArray[boffset + 0] = (byte) ((xint >> 24) & 0xff);
   }
 
   public void putByte(byte xbyte) {
     grow(1);
     byteArray[byteArray.length - 1] = xbyte;
   }
 
   public void putBytes(byte[] bytes) {
     int oldlen = byteArray.length;
     grow(bytes.length);
     System.arraycopy(bytes, 0, byteArray, oldlen, bytes.length);
   }
 
 
   /**
    * Add a SSH String to a packet. The incore representation is a
    *    INT32       length
    *    BYTE[length]    data
    * @param str: The string to be added.
    */
   public void putString(String str) {
     putInt32(str.length());
     putBytes(str.getBytes());
   }
 }