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a Java JDBC driver for reading comma-separated-value files
/*
* CsvJdbc - a JDBC driver for CSV files
* Copyright (C) 2001 Jonathan Ackerman
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* This library 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
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.relique.io;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
/**
* Example encryption filter that XOR's the all data with a secret seed value.
*/
public class XORCipher implements CryptoFilter
{
private int keyCounter;
private int[] scrambleKey;
public XORCipher(String seed)
{
scrambleKey = new int[seed.length()];
for (int i = 0; i < seed.length(); i++)
scrambleKey[i] = seed.charAt(i);
keyCounter = 0;
}
@Override
public int read(InputStream in) throws IOException
{
if (in.available() > 0)
{
return (byte) scrambleInt(in.read());
}
else
return -1;
}
@Override
public int read(InputStream in, byte[] b) throws IOException
{
int len;
len = in.read(b, 0, b.length);
scrambleArray(b);
return len;
}
@Override
public int read(InputStream in, byte[] b, int off, int len)
throws IOException
{
len = in.read(b, off, len);
scrambleArray(b);
return len;
}
@Override
public String toString()
{
StringBuilder sb = new StringBuilder("XORCipher(");
sb.append(scrambleKey.length);
sb.append("):");
sb.append(Arrays.toString(scrambleKey));
return sb.toString();
}
/**
* Perform the scrambling algorithm (named bitwise XOR encryption) using
* bitwise exclusive OR (byte) encrypted character = (byte) original
* character ^ (byte) key character.
*
* Note that ^ is the symbol for XOR (and not the mathematical power)
*
* @param org original value.
* @return scrambled value.
*/
private int scrambleInt(int org)
{
int encrDataChar = org;
if (scrambleKey.length > 0)
{
encrDataChar = org ^ scrambleKey[keyCounter];
keyCounter++;
keyCounter %= scrambleKey.length;
}
return encrDataChar;
}
/**
* Perform the scrambling algorithm (named bitwise XOR encryption) using
* bitwise exclusive OR (byte) encrypted character = (byte) original
* character ^ (byte) key character.
*
* Note that ^ is the symbol for XOR (and not the mathematical power)
*
* @param org original byte array.
* @return scrambled byte array.
*/
private void scrambleArray(byte[] org)
{
if (scrambleKey.length > 0)
{
for (int i = 0; i < org.length; i++)
{
org[i] ^= scrambleKey[keyCounter];
keyCounter++;
keyCounter %= scrambleKey.length;
}
}
}
@Override
public void write(OutputStream out, int ch) throws IOException
{
out.write(scrambleInt(ch));
}
@Override
public void reset()
{
keyCounter = 0;
}
}
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