QCodec.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.codec.net;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.BitSet;
import org.apache.commons.codec.Charsets;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.EncoderException;
import org.apache.commons.codec.StringDecoder;
import org.apache.commons.codec.StringEncoder;
/**
* Similar to the Quoted-Printable content-transfer-encoding defined in
* <a href="http://www.ietf.org/rfc/rfc1521.txt">RFC 1521</a> and designed to allow text containing mostly ASCII
* characters to be decipherable on an ASCII terminal without decoding.
* <p>
* <a href="http://www.ietf.org/rfc/rfc1522.txt">RFC 1522</a> describes techniques to allow the encoding of non-ASCII
* text in various portions of a RFC 822 [2] message header, in a manner which is unlikely to confuse existing message
* handling software.
* <p>
* This class is conditionally thread-safe.
* The instance field {@link #encodeBlanks} is mutable {@link #setEncodeBlanks(boolean)}
* but is not volatile, and accesses are not synchronised.
* If an instance of the class is shared between threads, the caller needs to ensure that suitable synchronisation
* is used to ensure safe publication of the value between threads, and must not invoke
* {@link #setEncodeBlanks(boolean)} after initial setup.
*
* @see <a href="http://www.ietf.org/rfc/rfc1522.txt">MIME (Multipurpose Internet Mail Extensions) Part Two: Message
* Header Extensions for Non-ASCII Text</a>
*
* @since 1.3
* @version $Id: QCodec.java 1619948 2014-08-22 22:53:55Z ggregory $
*/
public class QCodec extends RFC1522Codec implements StringEncoder, StringDecoder {
/**
* The default charset used for string decoding and encoding.
*/
private final Charset charset;
/**
* BitSet of printable characters as defined in RFC 1522.
*/
private static final BitSet PRINTABLE_CHARS = new BitSet(256);
// Static initializer for printable chars collection
static {
// alpha characters
PRINTABLE_CHARS.set(' ');
PRINTABLE_CHARS.set('!');
PRINTABLE_CHARS.set('"');
PRINTABLE_CHARS.set('#');
PRINTABLE_CHARS.set('$');
PRINTABLE_CHARS.set('%');
PRINTABLE_CHARS.set('&');
PRINTABLE_CHARS.set('\'');
PRINTABLE_CHARS.set('(');
PRINTABLE_CHARS.set(')');
PRINTABLE_CHARS.set('*');
PRINTABLE_CHARS.set('+');
PRINTABLE_CHARS.set(',');
PRINTABLE_CHARS.set('-');
PRINTABLE_CHARS.set('.');
PRINTABLE_CHARS.set('/');
for (int i = '0'; i <= '9'; i++) {
PRINTABLE_CHARS.set(i);
}
PRINTABLE_CHARS.set(':');
PRINTABLE_CHARS.set(';');
PRINTABLE_CHARS.set('<');
PRINTABLE_CHARS.set('>');
PRINTABLE_CHARS.set('@');
for (int i = 'A'; i <= 'Z'; i++) {
PRINTABLE_CHARS.set(i);
}
PRINTABLE_CHARS.set('[');
PRINTABLE_CHARS.set('\\');
PRINTABLE_CHARS.set(']');
PRINTABLE_CHARS.set('^');
PRINTABLE_CHARS.set('`');
for (int i = 'a'; i <= 'z'; i++) {
PRINTABLE_CHARS.set(i);
}
PRINTABLE_CHARS.set('{');
PRINTABLE_CHARS.set('|');
PRINTABLE_CHARS.set('}');
PRINTABLE_CHARS.set('~');
}
private static final byte BLANK = 32;
private static final byte UNDERSCORE = 95;
private boolean encodeBlanks = false;
/**
* Default constructor.
*/
public QCodec() {
this(Charsets.UTF_8);
}
/**
* Constructor which allows for the selection of a default charset.
*
* @param charset
* the default string charset to use.
*
* @see <a href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
* @since 1.7
*/
public QCodec(final Charset charset) {
super();
this.charset = charset;
}
/**
* Constructor which allows for the selection of a default charset.
*
* @param charsetName
* the charset to use.
* @throws java.nio.charset.UnsupportedCharsetException
* If the named charset is unavailable
* @since 1.7 throws UnsupportedCharsetException if the named charset is unavailable
* @see <a href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
*/
public QCodec(final String charsetName) {
this(Charset.forName(charsetName));
}
@Override
protected String getEncoding() {
return "Q";
}
@Override
protected byte[] doEncoding(final byte[] bytes) {
if (bytes == null) {
return null;
}
final byte[] data = QuotedPrintableCodec.encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
if (this.encodeBlanks) {
for (int i = 0; i < data.length; i++) {
if (data[i] == BLANK) {
data[i] = UNDERSCORE;
}
}
}
return data;
}
@Override
protected byte[] doDecoding(final byte[] bytes) throws DecoderException {
if (bytes == null) {
return null;
}
boolean hasUnderscores = false;
for (final byte b : bytes) {
if (b == UNDERSCORE) {
hasUnderscores = true;
break;
}
}
if (hasUnderscores) {
final byte[] tmp = new byte[bytes.length];
for (int i = 0; i < bytes.length; i++) {
final byte b = bytes[i];
if (b != UNDERSCORE) {
tmp[i] = b;
} else {
tmp[i] = BLANK;
}
}
return QuotedPrintableCodec.decodeQuotedPrintable(tmp);
}
return QuotedPrintableCodec.decodeQuotedPrintable(bytes);
}
/**
* Encodes a string into its quoted-printable form using the specified charset. Unsafe characters are escaped.
*
* @param str
* string to convert to quoted-printable form
* @param charset
* the charset for str
* @return quoted-printable string
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
* @since 1.7
*/
public String encode(final String str, final Charset charset) throws EncoderException {
if (str == null) {
return null;
}
return encodeText(str, charset);
}
/**
* Encodes a string into its quoted-printable form using the specified charset. Unsafe characters are escaped.
*
* @param str
* string to convert to quoted-printable form
* @param charset
* the charset for str
* @return quoted-printable string
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
public String encode(final String str, final String charset) throws EncoderException {
if (str == null) {
return null;
}
try {
return encodeText(str, charset);
} catch (final UnsupportedEncodingException e) {
throw new EncoderException(e.getMessage(), e);
}
}
/**
* Encodes a string into its quoted-printable form using the default charset. Unsafe characters are escaped.
*
* @param str
* string to convert to quoted-printable form
* @return quoted-printable string
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
@Override
public String encode(final String str) throws EncoderException {
if (str == null) {
return null;
}
return encode(str, getCharset());
}
/**
* Decodes a quoted-printable string into its original form. Escaped characters are converted back to their original
* representation.
*
* @param str
* quoted-printable string to convert into its original form
* @return original string
* @throws DecoderException
* A decoder exception is thrown if a failure condition is encountered during the decode process.
*/
@Override
public String decode(final String str) throws DecoderException {
if (str == null) {
return null;
}
try {
return decodeText(str);
} catch (final UnsupportedEncodingException e) {
throw new DecoderException(e.getMessage(), e);
}
}
/**
* Encodes an object into its quoted-printable form using the default charset. Unsafe characters are escaped.
*
* @param obj
* object to convert to quoted-printable form
* @return quoted-printable object
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
@Override
public Object encode(final Object obj) throws EncoderException {
if (obj == null) {
return null;
} else if (obj instanceof String) {
return encode((String) obj);
} else {
throw new EncoderException("Objects of type " +
obj.getClass().getName() +
" cannot be encoded using Q codec");
}
}
/**
* Decodes a quoted-printable object into its original form. Escaped characters are converted back to their original
* representation.
*
* @param obj
* quoted-printable object to convert into its original form
* @return original object
* @throws DecoderException
* Thrown if the argument is not a <code>String</code>. Thrown if a failure condition is encountered
* during the decode process.
*/
@Override
public Object decode(final Object obj) throws DecoderException {
if (obj == null) {
return null;
} else if (obj instanceof String) {
return decode((String) obj);
} else {
throw new DecoderException("Objects of type " +
obj.getClass().getName() +
" cannot be decoded using Q codec");
}
}
/**
* Gets the default charset name used for string decoding and encoding.
*
* @return the default charset name
* @since 1.7
*/
public Charset getCharset() {
return this.charset;
}
/**
* Gets the default charset name used for string decoding and encoding.
*
* @return the default charset name
*/
public String getDefaultCharset() {
return this.charset.name();
}
/**
* Tests if optional transformation of SPACE characters is to be used
*
* @return <code>true</code> if SPACE characters are to be transformed, <code>false</code> otherwise
*/
public boolean isEncodeBlanks() {
return this.encodeBlanks;
}
/**
* Defines whether optional transformation of SPACE characters is to be used
*
* @param b
* <code>true</code> if SPACE characters are to be transformed, <code>false</code> otherwise
*/
public void setEncodeBlanks(final boolean b) {
this.encodeBlanks = b;
}
}