/*
* Created on 17-Jan-2006
* Created by Paul Gardner
* Copyright (C) 2006 Aelitis, All Rights Reserved.
*
* 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.
*
* AELITIS, SAS au capital de 46,603.30 euros
* 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
*
*/
package com.aelitis.azureus.core.networkmanager.impl;
import java.io.IOException;
import java.nio.ByteBuffer;
public class
TransportHelperFilterStreamXOR
extends TransportHelperFilterStream
{
private byte[] mask;
private int read_position;
private int write_position;
protected
TransportHelperFilterStreamXOR(
TransportHelper _transport,
byte[] _mask )
{
super( _transport );
mask = _mask;
}
protected void
cryptoOut(
ByteBuffer source_buffer,
ByteBuffer target_buffer )
throws IOException
{
int rem = source_buffer.remaining();
for (int i=0;i<rem;i++){
byte b = source_buffer.get();
b = (byte)( b ^ mask[ write_position++ ]);
target_buffer.put( b );
if ( write_position == mask.length ){
write_position = 0;
}
}
}
protected void
cryptoIn(
ByteBuffer source_buffer,
ByteBuffer target_buffer )
throws IOException
{
int rem = source_buffer.remaining();
for (int i=0;i<rem;i++){
byte b = source_buffer.get();
b = (byte)( b ^ mask[ read_position++ ]);
target_buffer.put( b );
if ( read_position == mask.length ){
read_position = 0;
}
}
}
public boolean
isEncrypted()
{
return( true );
}
public String
getName()
{
return( "XOR-" + mask.length*8 + getHelper().getName());
}
}
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