|
Java example source code file (BASE64EncoderStream.java)
This example Java source code file (BASE64EncoderStream.java) is included in the alvinalexander.com
"Java Source Code
Warehouse" project. The intent of this project is to help you "Learn
Java by Example" TM.
Learn more about this Java project at its project page.
The BASE64EncoderStream.java Java example source code
/*
* Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @(#)BASE64EncoderStream.java 1.6 02/03/27
*/
package com.sun.xml.internal.messaging.saaj.packaging.mime.util;
import java.io.*;
/**
* This class implements a BASE64 Encoder. It is implemented as
* a FilterOutputStream, so one can just wrap this class around
* any output stream and write bytes into this filter. The Encoding
* is done as the bytes are written out.
*
* @author John Mani
* @author Bill Shannon
*/
public class BASE64EncoderStream extends FilterOutputStream {
private byte[] buffer; // cache of bytes that are yet to be encoded
private int bufsize = 0; // size of the cache
private int count = 0; // number of bytes that have been output
private int bytesPerLine; // number of bytes per line
/**
* Create a BASE64 encoder that encodes the specified input stream
* @param out the output stream
* @param bytesPerLine number of bytes per line. The encoder inserts
* a CRLF sequence after the specified number of bytes
*/
public BASE64EncoderStream(OutputStream out, int bytesPerLine) {
super(out);
buffer = new byte[3];
this.bytesPerLine = bytesPerLine;
}
/**
* Create a BASE64 encoder that encodes the specified input stream.
* Inserts the CRLF sequence after outputting 76 bytes.
* @param out the output stream
*/
public BASE64EncoderStream(OutputStream out) {
this(out, 76);
}
/**
* Encodes <code>len bytes from the specified
* <code>byte array starting at offset off to
* this output stream.
*
* @param b the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
* @exception IOException if an I/O error occurs.
*/
public void write(byte[] b, int off, int len) throws IOException {
for (int i = 0; i < len; i++)
write(b[off + i]);
}
/**
* Encodes <code>b.length bytes to this output stream.
* @param b the data to be written.
* @exception IOException if an I/O error occurs.
*/
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
/**
* Encodes the specified <code>byte to this output stream.
* @param c the <code>byte.
* @exception IOException if an I/O error occurs.
*/
public void write(int c) throws IOException {
buffer[bufsize++] = (byte)c;
if (bufsize == 3) { // Encoding unit = 3 bytes
encode();
bufsize = 0;
}
}
/**
* Flushes this output stream and forces any buffered output bytes
* to be encoded out to the stream.
* @exception IOException if an I/O error occurs.
*/
public void flush() throws IOException {
if (bufsize > 0) { // If there's unencoded characters in the buffer ..
encode(); // .. encode them
bufsize = 0;
}
out.flush();
}
/**
* Forces any buffered output bytes to be encoded out to the stream
* and closes this output stream
*/
public void close() throws IOException {
flush();
out.close();
}
/** This array maps the characters to their 6 bit values */
private final static char pem_array[] = {
'A','B','C','D','E','F','G','H', // 0
'I','J','K','L','M','N','O','P', // 1
'Q','R','S','T','U','V','W','X', // 2
'Y','Z','a','b','c','d','e','f', // 3
'g','h','i','j','k','l','m','n', // 4
'o','p','q','r','s','t','u','v', // 5
'w','x','y','z','0','1','2','3', // 6
'4','5','6','7','8','9','+','/' // 7
};
private void encode() throws IOException {
// If writing out this encoded unit will cause overflow,
// start a new line.
if (count + 4 > bytesPerLine) {
out.write('\r');
out.write('\n');
count = 0;
}
byte a, b, c;
if (bufsize == 1) {
a = buffer[0];
b = 0;
c = 0;
out.write(pem_array[(a >>> 2) & 0x3F]);
out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]);
out.write('='); // pad character
out.write('='); // pad character
} else if (bufsize == 2) {
a = buffer[0];
b = buffer[1];
c = 0;
out.write(pem_array[(a >>> 2) & 0x3F]);
out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]);
out.write(pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)]);
out.write('='); // pad character
} else {
a = buffer[0];
b = buffer[1];
c = buffer[2];
out.write(pem_array[(a >>> 2) & 0x3F]);
out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]);
out.write(pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)]);
out.write(pem_array[c & 0x3F]);
}
// increment count
count += 4;
}
/**
* Base64 encode a byte array. No line breaks are inserted.
* This method is suitable for short strings, such as those
* in the IMAP AUTHENTICATE protocol, but not to encode the
* entire content of a MIME part.
*/
public static byte[] encode(byte[] inbuf) {
if (inbuf.length == 0)
return inbuf;
byte[] outbuf = new byte[((inbuf.length + 2) / 3) * 4];
int inpos = 0, outpos = 0;
int size = inbuf.length;
while (size > 0) {
byte a, b, c;
if (size == 1) {
a = inbuf[inpos++];
b = 0;
c = 0;
outbuf[outpos++] = (byte)pem_array[(a >>> 2) & 0x3F];
outbuf[outpos++] =
(byte)pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)];
outbuf[outpos++] = (byte)'='; // pad character
outbuf[outpos++] = (byte)'='; // pad character
} else if (size == 2) {
a = inbuf[inpos++];
b = inbuf[inpos++];
c = 0;
outbuf[outpos++] = (byte)pem_array[(a >>> 2) & 0x3F];
outbuf[outpos++] =
(byte)pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)];
outbuf[outpos++] =
(byte)pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)];
outbuf[outpos++] = (byte)'='; // pad character
} else {
a = inbuf[inpos++];
b = inbuf[inpos++];
c = inbuf[inpos++];
outbuf[outpos++] = (byte)pem_array[(a >>> 2) & 0x3F];
outbuf[outpos++] =
(byte)pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)];
outbuf[outpos++] =
(byte)pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)];
outbuf[outpos++] = (byte)pem_array[c & 0x3F];
}
size -= 3;
}
return outbuf;
}
/*** begin TEST program
public static void main(String argv[]) throws Exception {
FileInputStream infile = new FileInputStream(argv[0]);
BASE64EncoderStream encoder = new BASE64EncoderStream(System.out);
int c;
while ((c = infile.read()) != -1)
encoder.write(c);
encoder.close();
}
*** end TEST program **/
}
Other Java examples (source code examples)
Here is a short list of links related to this Java BASE64EncoderStream.java source code file:
|