Mega Code Archive
A class to encode Base64 streams and strings
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/*
This file is part of Socks via HTTP.
This package 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.
Socks via HTTP 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 Socks via HTTP; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
// Title : Base64Encoder.java
// Version : 1.2
// Copyright : Copyright (c) 2001-2002
// Author : Florent CUETO & Sebastien LEBRETON <socksviahttp@cqs.dyndns.org>
// Description : Base 64 Encoder
//package socksviahttp.core.util;
import java.io.ByteArrayOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
/**
* A class to encode Base64 streams and strings. See RFC 1521 section 5.2 for
* details of the Base64 algorithm.
* <p>
* This class can be used for encoding strings: <blockquote>
*
* <pre>
* String unencoded = "webmaster:try2gueSS";
* String encoded = Base64Encoder.encode(unencoded);
* </pre>
*
* </blockquote> or for encoding streams: <blockquote>
*
* <pre>
* OutputStream out = new Base64Encoder(System.out);
* </pre>
*
* </blockquote>
*/
public class Base64Encoder extends FilterOutputStream {
private static final char[] chars = { 'A', 'B', 'C', 'D', 'E', 'F', 'G',
'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6',
'7', '8', '9', '+', '/' };
private int charCount;
private int carryOver;
/**
* Constructs a new Base64 encoder that writes output to the given
* OutputStream.
*
* @param out
* the output stream
*/
public Base64Encoder(OutputStream out) {
super(out);
}
/**
* Writes the given byte to the output stream in an encoded form.
*
* @exception IOException
* if an I/O error occurs
*/
public void write(int b) throws IOException {
// Take 24-bits from three octets, translate into four encoded chars
// Break lines at 76 chars
// If necessary, pad with 0 bits on the right at the end
// Use = signs as padding at the end to ensure encodedLength % 4 == 0
// Remove the sign bit,
// thanks to Christian Schweingruber <chrigu@lorraine.ch>
if (b < 0) {
b += 256;
}
// First byte use first six bits, save last two bits
if (charCount % 3 == 0) {
int lookup = b >> 2;
carryOver = b & 3; // last two bits
out.write(chars[lookup]);
}
// Second byte use previous two bits and first four new bits,
// save last four bits
else if (charCount % 3 == 1) {
int lookup = ((carryOver << 4) + (b >> 4)) & 63;
carryOver = b & 15; // last four bits
out.write(chars[lookup]);
}
// Third byte use previous four bits and first two new bits,
// then use last six new bits
else if (charCount % 3 == 2) {
int lookup = ((carryOver << 2) + (b >> 6)) & 63;
out.write(chars[lookup]);
lookup = b & 63; // last six bits
out.write(chars[lookup]);
carryOver = 0;
}
charCount++;
// Add newline every 76 output chars (that's 57 input chars)
if (charCount % 57 == 0) {
out.write('\n');
}
}
/**
* Writes the given byte array to the output stream in an encoded form.
*
* @param b
* the data to be written
* @param off
* the start offset of the data
* @param len
* the length of the data
* @exception IOException
* if an I/O error occurs
*/
public void write(byte[] b, int off, int len) throws IOException {
// This could of course be optimized
for (int i = 0; i < len; i++) {
write(b[off + i]);
}
}
/**
* Closes the stream, this MUST be called to ensure proper padding is
* written to the end of the output stream.
*
* @exception IOException
* if an I/O error occurs
*/
public void close() throws IOException {
// Handle leftover bytes
if (charCount % 3 == 1) { // one leftover
int lookup = (carryOver << 4) & 63;
out.write(chars[lookup]);
out.write('=');
out.write('=');
} else if (charCount % 3 == 2) { // two leftovers
int lookup = (carryOver << 2) & 63;
out.write(chars[lookup]);
out.write('=');
}
super.close();
}
/**
* Returns the encoded form of the given unencoded string.
*
* @param unencoded
* the string to encode
* @return the encoded form of the unencoded string
*/
public static String encode(String unencoded) {
ByteArrayOutputStream out = new ByteArrayOutputStream(
(int) (unencoded.length() * 1.37));
Base64Encoder encodedOut = new Base64Encoder(out);
byte[] bytes = null;
try {
bytes = unencoded.getBytes("8859_1");
} catch (UnsupportedEncodingException ignored) {
}
try {
encodedOut.write(bytes);
encodedOut.close();
return out.toString("8859_1");
} catch (IOException ignored) {
return null;
}
}
}
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