com.sun.mail.util.QDecoderStream Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2021 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 com.sun.mail.util;
import java.io.*;
/**
* This class implements a Q Decoder as defined in RFC 2047
* for decoding MIME headers. It subclasses the QPDecoderStream class.
*
* @author John Mani
*/
public class QDecoderStream extends QPDecoderStream {
/**
* Create a Q-decoder that decodes the specified input stream.
* @param in the input stream
*/
public QDecoderStream(InputStream in) {
super(in);
}
/**
* Read the next decoded byte from this input stream. The byte
* is returned as an int in the range 0
* to 255. If no byte is available because the end of
* the stream has been reached, the value -1 is returned.
* This method blocks until input data is available, the end of the
* stream is detected, or an exception is thrown.
*
* @return the next byte of data, or -1 if the end of the
* stream is reached.
* @exception IOException if an I/O error occurs.
*/
@Override
public int read() throws IOException {
int c = in.read();
if (c == '_') // Return '_' as ' '
return ' ';
else if (c == '=') {
// QP Encoded atom. Get the next two bytes ..
ba[0] = (byte)in.read();
ba[1] = (byte)in.read();
// .. and decode them
try {
return ASCIIUtility.parseInt(ba, 0, 2, 16);
} catch (NumberFormatException nex) {
throw new DecodingException(
"QDecoder: Error in QP stream " + nex.getMessage());
}
} else
return c;
}
}