Mega Code Archive
Allow text containing mostly ASCII characters to be decipherable on an ASCII terminal without decoding
<![CDATA[
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed 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.
*/
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.util.BitSet;
/**
* <p>
* 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>
*
* <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>
*
* @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>
*
* @author Apache Software Foundation
* @since 1.3
* @version $Id: QCodec.java,v 1.6 2004/05/24 00:24:32 ggregory Exp $
*/
public class QCodec extends RFC1522Codec {
/**
* The default charset used for string decoding and encoding.
*/
private String charset = "UTF8";
/**
* 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 byte BLANK = 32;
private static byte UNDERSCORE = 95;
private boolean encodeBlanks = false;
/**
* Default constructor.
*/
public QCodec() {
super();
}
/**
* Constructor which allows for the selection of a default charset
*
* @param charset
* the default string charset to use.
*
* @see <a href="http://java.sun.com/j2se/1.3/docs/api/java/lang/package-summary.html#charenc">JRE character
* encoding names</a>
*/
public QCodec(final String charset) {
super();
this.charset = charset;
}
protected String getEncoding() {
return "Q";
}
protected byte[] doEncoding(byte[] bytes) throws RuntimeException {
if (bytes == null) {
return null;
}
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;
}
protected byte[] doDecoding(byte[] bytes) throws Exception {
if (bytes == null) {
return null;
}
boolean hasUnderscores = false;
for (int i = 0; i < bytes.length; i++) {
if (bytes[i] == UNDERSCORE) {
hasUnderscores = true;
break;
}
}
if (hasUnderscores) {
byte[] tmp = new byte[bytes.length];
for (int i = 0; i < bytes.length; i++) {
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 pString
* string to convert to quoted-printable form
* @param charset
* the charset for pString
* @return quoted-printable string
*
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
public String encode(final String pString, final String charset) throws Exception {
if (pString == null) {
return null;
}
try {
return encodeText(pString, charset);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e.getMessage());
}
}
/**
* Encodes a string into its quoted-printable form using the default charset. Unsafe characters are escaped.
*
* @param pString
* string to convert to quoted-printable form
* @return quoted-printable string
*
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
public String encode(String pString) throws Exception {
if (pString == null) {
return null;
}
return encode(pString, getDefaultCharset());
}
/**
* Decodes a quoted-printable string into its original form. Escaped characters are converted back to their original
* representation.
*
* @param pString
* 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.
*/
public String decode(String pString) throws Exception {
if (pString == null) {
return null;
}
try {
return decodeText(pString);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e.getMessage());
}
}
/**
* Encodes an object into its quoted-printable form using the default charset. Unsafe characters are escaped.
*
* @param pObject
* object to convert to quoted-printable form
* @return quoted-printable object
*
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
public Object encode(Object pObject) throws Exception {
if (pObject == null) {
return null;
} else if (pObject instanceof String) {
return encode((String) pObject);
} else {
throw new RuntimeException("Objects of type "
+ pObject.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 pObject
* quoted-printable object to convert into its original form
*
* @return original object
*
* @throws DecoderException
* A decoder exception is thrown if a failure condition is encountered during the decode process.
*/
public Object decode(Object pObject) throws Exception {
if (pObject == null) {
return null;
} else if (pObject instanceof String) {
return decode((String) pObject);
} else {
throw new RuntimeException("Objects of type "
+ pObject.getClass().getName()
+ " cannot be decoded using Q codec");
}
}
/**
* The default charset used for string decoding and encoding.
*
* @return the default string charset.
*/
public String getDefaultCharset() {
return this.charset;
}
/**
* Tests if optional tranformation 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 tranformation 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(boolean b) {
this.encodeBlanks = b;
}
}
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed 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.
*/
/**
* <p>
* Implements methods common to all codecs defined in RFC 1522.
* </p>
*
* <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>
* @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>
* </p>
*
* @author Apache Software Foundation
* @since 1.3
* @version $Id: RFC1522Codec.java,v 1.2 2004/04/09 22:21:43 ggregory Exp $
*/
abstract class RFC1522Codec {
/**
* Applies an RFC 1522 compliant encoding scheme to the given string of text with the
* given charset. This method constructs the "encoded-word" header common to all the
* RFC 1522 codecs and then invokes {@link #doEncoding(byte [])} method of a concrete
* class to perform the specific enconding.
*
* @param text a string to encode
* @param charset a charset to be used
*
* @return RFC 1522 compliant "encoded-word"
*
* @throws EncoderException thrown if there is an error conidition during the Encoding
* process.
* @throws UnsupportedEncodingException thrown if charset is not supported
*
* @see <a href="http://java.sun.com/j2se/1.3/docs/api/java/lang/package-summary.html#charenc">JRE character
* encoding names</a>
*/
protected String encodeText(final String text, final String charset)
throws Exception, UnsupportedEncodingException
{
if (text == null) {
return null;
}
StringBuffer buffer = new StringBuffer();
buffer.append("=?");
buffer.append(charset);
buffer.append('?');
buffer.append(getEncoding());
buffer.append('?');
byte [] rawdata = doEncoding(text.getBytes(charset));
buffer.append(new String(rawdata, "US-ASCII"));
buffer.append("?=");
return buffer.toString();
}
/**
* Applies an RFC 1522 compliant decoding scheme to the given string of text. This method
* processes the "encoded-word" header common to all the RFC 1522 codecs and then invokes
* {@link #doEncoding(byte [])} method of a concrete class to perform the specific deconding.
*
* @param text a string to decode
*
* @throws DecoderException thrown if there is an error conidition during the Decoding
* process.
* @throws UnsupportedEncodingException thrown if charset specified in the "encoded-word"
* header is not supported
*/
protected String decodeText(final String text)
throws Exception, UnsupportedEncodingException
{
if (text == null) {
return null;
}
if ((!text.startsWith("=?")) || (!text.endsWith("?="))) {
throw new RuntimeException("RFC 1522 violation: malformed encoded content");
}
int termnator = text.length() - 2;
int from = 2;
int to = text.indexOf("?", from);
if ((to == -1) || (to == termnator)) {
throw new RuntimeException("RFC 1522 violation: charset token not found");
}
String charset = text.substring(from, to);
if (charset.equals("")) {
throw new RuntimeException("RFC 1522 violation: charset not specified");
}
from = to + 1;
to = text.indexOf("?", from);
if ((to == -1) || (to == termnator)) {
throw new RuntimeException("RFC 1522 violation: encoding token not found");
}
String encoding = text.substring(from, to);
if (!getEncoding().equalsIgnoreCase(encoding)) {
throw new RuntimeException("This codec cannot decode " +
encoding + " encoded content");
}
from = to + 1;
to = text.indexOf("?", from);
byte[] data = text.substring(from, to).getBytes("US-ASCII");
data = doDecoding(data);
return new String(data, charset);
}
/**
* Returns the codec name (referred to as encoding in the RFC 1522)
*
* @return name of the codec
*/
protected abstract String getEncoding();
/**
* Encodes an array of bytes using the defined encoding scheme
*
* @param bytes Data to be encoded
*
* @return A byte array containing the encoded data
*
* @throws EncoderException thrown if the Encoder encounters a failure condition
* during the encoding process.
*/
protected abstract byte[] doEncoding(byte[] bytes) throws Exception;
/**
* Decodes an array of bytes using the defined encoding scheme
*
* @param bytes Data to be decoded
*
* @return a byte array that contains decoded data
*
* @throws DecoderException A decoder exception is thrown if a Decoder encounters a
* failure condition during the decode process.
*/
protected abstract byte[] doDecoding(byte[] bytes) throws Exception;
}
class QuotedPrintableCodec {
/**
* The default charset used for string decoding and encoding.
*/
private String charset = "UTF8";
/**
* BitSet of printable characters as defined in RFC 1521.
*/
private static final BitSet PRINTABLE_CHARS = new BitSet(256);
private static byte ESCAPE_CHAR = '=';
private static byte TAB = 9;
private static byte SPACE = 32;
// Static initializer for printable chars collection
static {
// alpha characters
for (int i = 33; i <= 60; i++) {
PRINTABLE_CHARS.set(i);
}
for (int i = 62; i <= 126; i++) {
PRINTABLE_CHARS.set(i);
}
PRINTABLE_CHARS.set(TAB);
PRINTABLE_CHARS.set(SPACE);
}
/**
* Default constructor.
*/
public QuotedPrintableCodec() {
super();
}
/**
* Constructor which allows for the selection of a default charset
*
* @param charset
* the default string charset to use.
*/
public QuotedPrintableCodec(String charset) {
super();
this.charset = charset;
}
/**
* Encodes byte into its quoted-printable representation.
*
* @param b
* byte to encode
* @param buffer
* the buffer to write to
*/
private static final void encodeQuotedPrintable(int b, ByteArrayOutputStream buffer) {
buffer.write(ESCAPE_CHAR);
char hex1 = Character.toUpperCase(Character.forDigit((b >> 4) & 0xF, 16));
char hex2 = Character.toUpperCase(Character.forDigit(b & 0xF, 16));
buffer.write(hex1);
buffer.write(hex2);
}
/**
* Encodes an array of bytes into an array of quoted-printable 7-bit characters. Unsafe characters are escaped.
*
* <p>
* This function implements a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in
* RFC 1521 and is suitable for encoding binary data and unformatted text.
* </p>
*
* @param printable
* bitset of characters deemed quoted-printable
* @param bytes
* array of bytes to be encoded
* @return array of bytes containing quoted-printable data
*/
public static final byte[] encodeQuotedPrintable(BitSet printable, byte[] bytes) {
if (bytes == null) {
return null;
}
if (printable == null) {
printable = PRINTABLE_CHARS;
}
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
for (int i = 0; i < bytes.length; i++) {
int b = bytes[i];
if (b < 0) {
b = 256 + b;
}
if (printable.get(b)) {
buffer.write(b);
} else {
encodeQuotedPrintable(b, buffer);
}
}
return buffer.toByteArray();
}
/**
* Decodes an array quoted-printable characters into an array of original bytes. Escaped characters are converted
* back to their original representation.
*
* <p>
* This function implements a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in
* RFC 1521.
* </p>
*
* @param bytes
* array of quoted-printable characters
* @return array of original bytes
* @throws DecoderException
* Thrown if quoted-printable decoding is unsuccessful
*/
public static final byte[] decodeQuotedPrintable(byte[] bytes) throws Exception {
if (bytes == null) {
return null;
}
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
for (int i = 0; i < bytes.length; i++) {
int b = bytes[i];
if (b == ESCAPE_CHAR) {
try {
int u = Character.digit((char) bytes[++i], 16);
int l = Character.digit((char) bytes[++i], 16);
if (u == -1 || l == -1) {
throw new RuntimeException("Invalid quoted-printable encoding");
}
buffer.write((char) ((u << 4) + l));
} catch (ArrayIndexOutOfBoundsException e) {
throw new RuntimeException("Invalid quoted-printable encoding");
}
} else {
buffer.write(b);
}
}
return buffer.toByteArray();
}
/**
* Encodes an array of bytes into an array of quoted-printable 7-bit characters. Unsafe characters are escaped.
*
* <p>
* This function implements a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in
* RFC 1521 and is suitable for encoding binary data and unformatted text.
* </p>
*
* @param bytes
* array of bytes to be encoded
* @return array of bytes containing quoted-printable data
*/
public byte[] encode(byte[] bytes) {
return encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
}
/**
* Decodes an array of quoted-printable characters into an array of original bytes. Escaped characters are converted
* back to their original representation.
*
* <p>
* This function implements a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in
* RFC 1521.
* </p>
*
* @param bytes
* array of quoted-printable characters
* @return array of original bytes
* @throws DecoderException
* Thrown if quoted-printable decoding is unsuccessful
*/
public byte[] decode(byte[] bytes) throws Exception {
return decodeQuotedPrintable(bytes);
}
/**
* Encodes a string into its quoted-printable form using the default string charset. Unsafe characters are escaped.
*
* <p>
* This function implements a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in
* RFC 1521 and is suitable for encoding binary data.
* </p>
*
* @param pString
* string to convert to quoted-printable form
* @return quoted-printable string
*
* @throws EncoderException
* Thrown if quoted-printable encoding is unsuccessful
*
* @see #getDefaultCharset()
*/
public String encode(String pString) throws Exception {
if (pString == null) {
return null;
}
try {
return encode(pString, getDefaultCharset());
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e.getMessage());
}
}
/**
* Decodes a quoted-printable string into its original form using the specified string charset. Escaped characters
* are converted back to their original representation.
*
* @param pString
* quoted-printable string to convert into its original form
* @param charset
* the original string charset
* @return original string
* @throws DecoderException
* Thrown if quoted-printable decoding is unsuccessful
* @throws UnsupportedEncodingException
* Thrown if charset is not supported
*/
public String decode(String pString, String charset) throws Exception, UnsupportedEncodingException {
if (pString == null) {
return null;
}
return new String(decode(pString.getBytes("US-ASCII")), charset);
}
/**
* Decodes a quoted-printable string into its original form using the default string charset. Escaped characters are
* converted back to their original representation.
*
* @param pString
* quoted-printable string to convert into its original form
* @return original string
* @throws DecoderException
* Thrown if quoted-printable decoding is unsuccessful
* @throws UnsupportedEncodingException
* Thrown if charset is not supported
* @see #getDefaultCharset()
*/
public String decode(String pString) throws Exception {
if (pString == null) {
return null;
}
try {
return decode(pString, getDefaultCharset());
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e.getMessage());
}
}
/**
* Encodes an object into its quoted-printable safe form. Unsafe characters are escaped.
*
* @param pObject
* string to convert to a quoted-printable form
* @return quoted-printable object
* @throws EncoderException
* Thrown if quoted-printable encoding is not applicable to objects of this type or if encoding is
* unsuccessful
*/
public Object encode(Object pObject) throws Exception {
if (pObject == null) {
return null;
} else if (pObject instanceof byte[]) {
return encode((byte[]) pObject);
} else if (pObject instanceof String) {
return encode((String) pObject);
} else {
throw new RuntimeException("Objects of type "
+ pObject.getClass().getName()
+ " cannot be quoted-printable encoded");
}
}
/**
* Decodes a quoted-printable object into its original form. Escaped characters are converted back to their original
* representation.
*
* @param pObject
* quoted-printable object to convert into its original form
* @return original object
* @throws DecoderException
* Thrown if quoted-printable decoding is not applicable to objects of this type if decoding is
* unsuccessful
*/
public Object decode(Object pObject) throws Exception {
if (pObject == null) {
return null;
} else if (pObject instanceof byte[]) {
return decode((byte[]) pObject);
} else if (pObject instanceof String) {
return decode((String) pObject);
} else {
throw new RuntimeException("Objects of type "
+ pObject.getClass().getName()
+ " cannot be quoted-printable decoded");
}
}
/**
* Returns the default charset used for string decoding and encoding.
*
* @return the default string charset.
*/
public String getDefaultCharset() {
return this.charset;
}
/**
* Encodes a string into its quoted-printable form using the specified charset. Unsafe characters are escaped.
*
* <p>
* This function implements a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in
* RFC 1521 and is suitable for encoding binary data and unformatted text.
* </p>
*
* @param pString
* string to convert to quoted-printable form
* @param charset
* the charset for pString
* @return quoted-printable string
*
* @throws UnsupportedEncodingException
* Thrown if the charset is not supported
*/
public String encode(String pString, String charset) throws UnsupportedEncodingException {
if (pString == null) {
return null;
}
return new String(encode(pString.getBytes(charset)), "US-ASCII");
}
}
]]>