/**************************************************************************
* Copyright (c) 2006 by Chris Gray, /k/ Embedded Java Solutions. *
* All rights reserved. *
* *
* Redistribution and use in source and binary forms, with or without *
* modification, are permitted provided that the following conditions *
* are met: *
* 1. Redistributions of source code must retain the above copyright *
* notice, this list of conditions and the following disclaimer. *
* 2. Redistributions in binary form must reproduce the above copyright *
* notice, this list of conditions and the following disclaimer in the *
* documentation and/or other materials provided with the distribution. *
* 3. Neither the name of /k/ Embedded Java Solutions nor the names of *
* other contributors may be used to endorse or promote products *
* derived from this software without specific prior written permission.*
* *
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED *
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF *
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. *
* IN NO EVENT SHALL /K/ EMBEDDED JAVA SOLUTIONS OR OTHER CONTRIBUTORS BE *
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR *
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF *
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR *
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, *
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE *
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN *
* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. *
**************************************************************************/
package wonka.encoder;
import java.io.*;
/**
* A class to encode Base64 streams and strings.
* See RFC 1521 section 5.2 for details of the Base64 algorithm.
*
* This class can be used for encoding strings:
*
* String unencoded = "webmaster:try2gueSS";
* String encoded = Base64Encoder.encode(unencoded);
*
* or for encoding streams:
*
* OutputStream out = new Base64Encoder(System.out);
*
*
* @author Jason Hunter, Copyright � 2000
* @version 1.0, 2000/06/11
*/
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
b &= 0xff;
// 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('=');
} else {
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; }
}
public static void main(String[] args) throws Exception {
if (args.length != 1) {
System.err.println("Usage: java Base64Encoder fileToEncode");
}
Base64Encoder encoder = null;
BufferedInputStream in = null;
try {
encoder = new Base64Encoder(System.out);
in = new BufferedInputStream(new FileInputStream(args[0]));
byte[] buf = new byte[4 * 1024]; // 4K buffer
int bytesRead;
while ((bytesRead = in.read(buf)) != -1) {
encoder.write(buf, 0, bytesRead);
}
}
finally {
if (in != null) in.close();
if (encoder != null) encoder.close();
}
}
}