sdsu.io
Class XorReader

java.lang.Object
  |
  +--java.io.Reader
        |
        +--java.io.FilterReader
              |
              +--sdsu.io.XorReader

public class XorReader

extends java.io.FilterReader

XorReader is an inputstream that Xor all input bytes with the byte mask given in the constructor. Use to decode output of a XorWriter by giving it the XorReader the same byte mask as XorWriter. XorReader and XorWriter can be used for a very weak form of encryption.

Version:

1.0 14 Feb 1998

Author:

Roger Whitney (whitney@cs.sdsu.edu)

Constructor Summary

XorReader(java.io.Reader in, char mask)
Create an XorReader on the given input stream.

Method Summary

int	read() Reads the next char of data and Xors it with the mask given in the constructor.
int	read(char[] inputBuffer, int offset, int length) Reads up to length chars of data and Xor each char.

Methods inherited from class java.io.FilterReader

close, mark, markSupported, ready, reset, skip

Methods inherited from class java.io.Reader

read

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

XorReader

public XorReader(java.io.Reader in,
                 char mask)

Create an XorReader on the given input stream.

Parameters:

mask - the bit pattern with which all input bytes will be Xored

Method Detail

read

public int read()
         throws java.io.IOException

Reads the next char of data and Xors it with the mask given in the constructor. If no char is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Returns:

the next char of data, or -1 if the end of the stream is reached.

Throws:

java.io.IOException - if an I/O error occurs.

Overrides:

read in class java.io.FilterReader

read

public int read(char[] inputBuffer,
                int offset,
                int length)
         throws java.io.IOException

Reads up to length chars of data and Xor each char. This method blocks until some input is available.

Parameters:

inputBuffer - the buffer into which the data is read.

offset - the start offset of the data.

length - the maximum number of chars read.

Returns:

the total number of chars read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

java.io.IOException - if an I/O error occurs.

Overrides:

read in class java.io.FilterReader