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/*
* @(#)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, Bill Shannon
/**
* 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
Params: - out – the output stream
- bytesPerLine – number of bytes per line. The encoder inserts
a CRLF sequence after the specified number of bytes
/**
* 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.
Params: - out – the output stream
/**
* 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 len bytes from the specified
byte array starting at offset off to
this output stream.
Params: - b – the data.
- off – the start offset in the data.
- len – the number of bytes to write.
Throws: - IOException – if an I/O error occurs.
/**
* Encodes <code>len</code> bytes from the specified
* <code>byte</code> array starting at offset <code>off</code> 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.
*/
@Override
public void write(byte[] b, int off, int len) throws IOException {
for (int i = 0; i < len; i++)
write(b[off + i]);
}
Encodes b.length bytes to this output stream.
Params: - b – the data to be written.
Throws: - IOException – if an I/O error occurs.
/**
* Encodes <code>b.length</code> bytes to this output stream.
* @param b the data to be written.
* @exception IOException if an I/O error occurs.
*/
@Override
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
Encodes the specified byte to this output stream.
Params: - c – the
byte.
Throws: - IOException – if an I/O error occurs.
/**
* Encodes the specified <code>byte</code> to this output stream.
* @param c the <code>byte</code>.
* @exception IOException if an I/O error occurs.
*/
@Override
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.
Throws: - IOException – if an I/O error occurs.
/**
* 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.
*/
@Override
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
/**
* Forces any buffered output bytes to be encoded out to the stream
* and closes this output stream
*/
@Override
public void close() throws IOException {
flush();
out.close();
}
This array maps the characters to their 6 bit values /** 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.
Params: - inbuf – byte array to encode.
Returns: encoded byte array.
/**
* 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.
*
* @param inbuf byte array to encode.
*
* @return encoded byte array.
*/
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 **/
}