gecko-dev/grendel/mime/encoder/MimeUUEncoder.java

131 строка
4.7 KiB
Java

/* -*- Mode: java; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Grendel mail/news client.
*
* The Initial Developer of the Original Code is Netscape Communications
* Corporation. Portions created by Netscape are
* Copyright (C) 1997 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*
* Created: Jamie Zawinski <jwz@netscape.com>, 28 Aug 1997.
*
* Contributors: Edwin Woudt <edwin@woudt.nl>
*/
package grendel.mime.encoder;
import calypso.util.ByteBuf;
/** Implements a plaintext -> uuencode encoder.
*/
public final class MimeUUEncoder extends MimeEncoder {
private byte name[] = null; // name for the "begin" line
private int buf = 0; // a 24-bit quantity
private int buf_bytes = 0; // how many octets are set in it
private byte line[] = new byte[63]; // output buffer
private int line_length = 1; // output buffer fill pointer
static private final byte begin_644[] = "begin 644 ".getBytes();
static private final byte crlf[] = "\r\n".getBytes();
static private final byte end_crlf[] = "end\r\n".getBytes();
static private final byte map[] = {
(byte)'`', (byte)'!', (byte)'"', (byte)'#', (byte)'$', (byte)'%', (byte)'&', (byte)'\'', // 0-7
(byte)'(', (byte)')', (byte)'*', (byte)'+', (byte)',', (byte)'-', (byte)'.', (byte)'/', // 8-15
(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7', // 16-23
(byte)'8', (byte)'9', (byte)':', (byte)';', (byte)'<', (byte)'=', (byte)'>', (byte)'?', // 24-31
(byte)'@', (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G', // 32-39
(byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N', (byte)'O', // 40-47
(byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', (byte)'V', (byte)'W', // 48-55
(byte)'X', (byte)'Y', (byte)'Z', (byte)'[', (byte)'\\',(byte)']', (byte)'^', (byte)'_', // 56-63
};
public MimeUUEncoder(String file_name) {
this.name = file_name.getBytes();
}
private final void encode_token() {
int i = line_length;
line[i] = map[0x3F & (buf >> 18)]; // sextet 1 (octet 1)
line[i+1] = map[0x3F & (buf >> 12)]; // sextet 2 (octet 1 and 2)
line[i+2] = map[0x3F & (buf >> 6)]; // sextet 3 (octet 2 and 3)
line[i+3] = map[0x3F & buf]; // sextet 4 (octet 3)
line_length += 4;
buf = 0;
buf_bytes = 0;
}
private final void flush_line(ByteBuf out, int offset) {
line[0] = map[(line_length * 3 / 4) - offset];
line[line_length] = (byte)'\r';
line[line_length+1] = (byte)'\n';
out.append(line, 0, line_length + 2);
line_length = 1;
}
/** Given a sequence of input bytes, produces a sequence of output bytes
using uu encoding. If there are bytes in `out' already, the new bytes
are appended, so the caller should do `out.setLength(0)' first if that's
desired.
*/
public final void translate(ByteBuf in, ByteBuf out) {
if (name != null) {
out.append(begin_644);
out.append(name);
out.append(crlf);
name = null;
}
byte inb[] = in.toBytes();
int in_length = in.length();
for (int i = 0; i < in_length; i++) {
if (buf_bytes == 0)
buf = (buf & 0x00FFFF) | (inb[i] << 16);
else if (buf_bytes == 1)
buf = (buf & 0xFF00FF) | (inb[i] << 8);
else
buf = (buf & 0xFFFF00) | (inb[i]);
if ((++buf_bytes) == 3) {
encode_token();
if (line_length >= 60)
flush_line(out, 0);
}
}
}
/** Tell the uu encoder that no more input data will be forthcoming.
This may result in output, as a result of flushing the internal buffer.
This object must not be used again after calling eof(). If there are
bytes in `out' already, the new bytes are appended, so the caller should
do `out.setLength(0)' first if that's desired.
*/
public final void eof(ByteBuf out) {
if (buf_bytes != 0) {
int off = 3 - buf_bytes;
encode_token();
flush_line(out, off);
}
flush_line(out, 0);
name = null;
line = null;
out.append(end_crlf);
}
}