/*
* Copyright (c) 1998, 1999 Sun Microsystems, Inc. All Rights Reserved.
*
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
*/
package examples.rmisocfac;
import java.io.*;
class XorInputStream extends FilterInputStream {
/*
* The byte being used to "decrypt" each byte of data.
* Default is 10101010.
*/
private byte pattern = (byte)(170 & 0xFF);
/*
* Constructor for class XorInputStream
*/
public XorInputStream(InputStream in, byte pattern) {
super(in);
if (pattern != 0)
this.pattern = pattern;
}
/*
* Reads in a byte and xor's the byte with the pattern.
* Returns the byte.
*/
public int read() throws IOException {
int b = in.read();
//If not end of file or an error, truncate b to one byte
if (b != -1)
b = (b ^ pattern) & 0xFF;
return b;
}
/*
* Reads up to len bytes
*/
public int read(byte b[], int off, int len) throws IOException {
int numBytes = in.read(b, off, len);
if (numBytes <= 0)
return numBytes;
int i = 0;
for(; i < numBytes; i++) {
b[off + i] = (byte)((b[off + i] ^ pattern) & 0xFF);
}
return i;
}
}
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