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/*
* QOutputStream.java
* Copyright (C) 2002 The Free Software Foundation
*
* This file is part of GNU JavaMail, a library.
*
* GNU JavaMail is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GNU JavaMail 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* As a special exception, if you link this library with other files to
* produce an executable, this library does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* This exception does not however invalidate any other reasons why the
* executable file might be covered by the GNU General Public License.
*/
/*
* QOutputStream.java
* Copyright (C) 2002 The Free Software Foundation
*
* This file is part of GNU JavaMail, a library.
*
* GNU JavaMail is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GNU JavaMail 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* As a special exception, if you link this library with other files to
* produce an executable, this library does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* This exception does not however invalidate any other reasons why the
* executable file might be covered by the GNU General Public License.
*/
package gnu.mail.util;
import java.io.IOException;
import java.io.OutputStream;
/**
* Provides RFC 2047 "B" transfer decoding.
* See section 4.2:
* <p>
* The "Q" encoding is similar to the "Quoted-Printable" content-
* transfer-encoding defined in RFC 2045. It is designed to allow text
* containing mostly ASCII characters to be decipherable on an ASCII
* terminal without decoding.
* <ol>
* <li>Any 8-bit value may be represented by a "=" followed by two
* hexadecimal digits. For example, if the character set in use
* were ISO-8859-1, the "=" character would thus be encoded as
* "=3D", and a SPACE by "=20". (Upper case should be used for
* hexadecimal digits "A" through "F".)
* <li>The 8-bit hexadecimal value 20 (e.g., ISO-8859-1 SPACE) may be
* represented as "_" (underscore, ASCII 95.). (This character may
* not pass through some internetwork mail gateways, but its use
* will greatly enhance readability of "Q" encoded data with mail
* readers that do not support this encoding.) Note that the "_"
* always represents hexadecimal 20, even if the SPACE character
* occupies a different code position in the character set in use.
* <li>8-bit values which correspond to printable ASCII characters other
* than "=", "?", and "_" (underscore), MAY be represented as those
* characters. (But see section 5 for restrictions.) In
* particular, SPACE and TAB MUST NOT be represented as themselves
* within encoded words.
*
* @author <a href="mailto:dog@gnu.org">Chris Burdess</a>
*/
public class QOutputStream
extends QPOutputStream
{
private static final int SPACE = 32;
private static final int UNDERSCORE = 95;
private static String TEXT_SPECIALS = "=_?";
private static String WORD_SPECIALS = "=_?\"#$%&'(),.:;<>@[\\]^`{|}~";
private String specials;
/**
* Constructor.
* The <code>word</code> parameter is used to indicate whether the bytes
* passed to this stream are considered to be RFC 822 "word" tokens or
* "text" tokens.
* @param out the underlying output stream
* @param word word mode if true, text mode otherwise
*/
public QOutputStream(OutputStream out, boolean word)
{
super(out, 0x7fffffff);
specials = word ? WORD_SPECIALS : TEXT_SPECIALS;
}
/**
* Write a character to the stream.
*/
public void write(int c)
throws IOException
{
c &= 0xff;
if (c==SPACE)
output(UNDERSCORE, false);
else
{
if (c<32 || c>=127 || specials.indexOf(c)>=0)
output(c, true);
else
output(c, false);
}
}
public static int encodedLength(byte[] bytes, boolean word)
{
int len = 0;
String specials = word ? WORD_SPECIALS : TEXT_SPECIALS;
for(int i = 0; i<bytes.length; i++)
{
int c = bytes[i]&0xff;
if (c<32 || c>=127 || specials.indexOf(c)>=0)
len += 3;
else
len++;
}
return len;
}
}
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