org.eclipse.angus.mail.util.UUEncoderStream Maven / Gradle / Ivy
The newest version!
/*
* Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package org.eclipse.angus.mail.util;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
/**
* This class implements a UUEncoder. 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
*/
public class UUEncoderStream extends FilterOutputStream {
private byte[] buffer; // cache of bytes that are yet to be encoded
private int bufsize = 0; // size of the cache
private boolean wrotePrefix = false;
private boolean wroteSuffix = false;
private String name; // name of file
private int mode; // permissions mode
/**
* Create a UUencoder that encodes the specified input stream
*
* @param out the output stream
*/
public UUEncoderStream(OutputStream out) {
this(out, "encoder.buf", 0644);
}
/**
* Create a UUencoder that encodes the specified input stream
*
* @param out the output stream
* @param name Specifies a name for the encoded buffer
*/
public UUEncoderStream(OutputStream out, String name) {
this(out, name, 0644);
}
/**
* Create a UUencoder that encodes the specified input stream
*
* @param out the output stream
* @param name Specifies a name for the encoded buffer
* @param mode Specifies permission mode for the encoded buffer
*/
public UUEncoderStream(OutputStream out, String name, int mode) {
super(out);
this.name = name;
this.mode = mode;
buffer = new byte[45];
}
/**
* Set up the buffer name and permission mode.
* This method has any effect only if it is invoked before
* you start writing into the output stream
*
* @param name the buffer name
* @param mode the permission mode
*/
public void setNameMode(String name, int mode) {
this.name = name;
this.mode = mode;
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
for (int i = 0; i < len; i++)
write(b[off + i]);
}
@Override
public void write(byte[] data) throws IOException {
write(data, 0, data.length);
}
@Override
public void write(int c) throws IOException {
/* buffer up characters till we get a line's worth, then encode
* and write them out. Max number of characters allowed per
* line is 45.
*/
buffer[bufsize++] = (byte) c;
if (bufsize == 45) {
writePrefix();
encode();
bufsize = 0;
}
}
@Override
public void flush() throws IOException {
if (bufsize > 0) { // If there's unencoded characters in the buffer
writePrefix();
encode(); // .. encode them
bufsize = 0;
}
writeSuffix();
out.flush();
}
@Override
public void close() throws IOException {
flush();
out.close();
}
/**
* Write out the prefix: "begin "
*/
private void writePrefix() throws IOException {
if (!wrotePrefix) {
// name should be ASCII, but who knows...
PrintStream ps = new PrintStream(out, false, "utf-8");
ps.format("begin %o %s%n", mode, name);
ps.flush();
wrotePrefix = true;
}
}
/**
* Write a single line containing space and the suffix line
* containing the single word "end" (terminated by a newline)
*/
private void writeSuffix() throws IOException {
if (!wroteSuffix) {
PrintStream ps = new PrintStream(out, false, "us-ascii");
ps.println(" \nend");
ps.flush();
wroteSuffix = true;
}
}
/**
* Encode a line.
* Start off with the character count, followed by the encoded atoms
* and terminate with LF. (or is it CRLF or the local line-terminator ?)
* Take three bytes and encodes them into 4 characters
* If bufsize if not a multiple of 3, the remaining bytes are filled
* with '1'. This insures that the last line won't end in spaces
* and potentiallly be truncated.
*/
private void encode() throws IOException {
byte a, b, c;
int c1, c2, c3, c4;
int i = 0;
// Start off with the count of characters in the line
out.write((bufsize & 0x3f) + ' ');
while (i < bufsize) {
a = buffer[i++];
if (i < bufsize) {
b = buffer[i++];
if (i < bufsize)
c = buffer[i++];
else // default c to 1
c = 1;
} else { // default b & c to 1
b = 1;
c = 1;
}
c1 = (a >>> 2) & 0x3f;
c2 = ((a << 4) & 0x30) | ((b >>> 4) & 0xf);
c3 = ((b << 2) & 0x3c) | ((c >>> 6) & 0x3);
c4 = c & 0x3f;
out.write(c1 + ' ');
out.write(c2 + ' ');
out.write(c3 + ' ');
out.write(c4 + ' ');
}
// Terminate with LF. (should it be CRLF or local line-terminator ?)
out.write('\n');
}
/**** begin TEST program *****
public static void main(String argv[]) throws Exception {
FileInputStream infile = new FileInputStream(argv[0]);
UUEncoderStream encoder = new UUEncoderStream(System.out);
int c;
while ((c = infile.read()) != -1)
encoder.write(c);
encoder.close();
}
**** end TEST program *****/
}