Source code

001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      https://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.codec.net;
019
020import java.io.UnsupportedEncodingException;
021import java.nio.charset.Charset;
022import java.nio.charset.StandardCharsets;
023import java.nio.charset.UnsupportedCharsetException;
024import java.util.BitSet;
025
026import org.apache.commons.codec.DecoderException;
027import org.apache.commons.codec.EncoderException;
028import org.apache.commons.codec.StringDecoder;
029import org.apache.commons.codec.StringEncoder;
030
031/**
032 * Similar to the Quoted-Printable content-transfer-encoding defined in
033 * <a href="https://www.ietf.org/rfc/rfc1521.txt">RFC 1521</a> and designed to allow text containing mostly ASCII
034 * characters to be decipherable on an ASCII terminal without decoding.
035 * <p>
036 * <a href="https://www.ietf.org/rfc/rfc1522.txt">RFC 1522</a> describes techniques to allow the encoding of non-ASCII
037 * text in various portions of a RFC 822 [2] message header, in a manner which is unlikely to confuse existing message
038 * handling software.
039 * </p>
040 * <p>
041 * This class is conditionally thread-safe.
042 * The instance field for encoding blanks is mutable {@link #setEncodeBlanks(boolean)}
043 * but is not volatile, and accesses are not synchronized.
044 * If an instance of the class is shared between threads, the caller needs to ensure that suitable synchronization
045 * is used to ensure safe publication of the value between threads, and must not invoke
046 * {@link #setEncodeBlanks(boolean)} after initial setup.
047 * </p>
048 *
049 * @see <a href="https://www.ietf.org/rfc/rfc1522.txt">MIME (Multipurpose Internet Mail Extensions) Part Two: Message
050 *          Header Extensions for Non-ASCII Text</a>
051 *
052 * @since 1.3
053 */
054public class QCodec extends RFC1522Codec implements StringEncoder, StringDecoder {
055
056    /**
057     * BitSet of printable characters as defined in RFC 1522.
058     */
059    private static final BitSet PRINTABLE_CHARS = new BitSet(256);
060
061    // Static initializer for printable chars collection
062    static {
063        // alpha characters
064        PRINTABLE_CHARS.set(' ');
065        PRINTABLE_CHARS.set('!');
066        PRINTABLE_CHARS.set('"');
067        PRINTABLE_CHARS.set('#');
068        PRINTABLE_CHARS.set('$');
069        PRINTABLE_CHARS.set('%');
070        PRINTABLE_CHARS.set('&');
071        PRINTABLE_CHARS.set('\'');
072        PRINTABLE_CHARS.set('(');
073        PRINTABLE_CHARS.set(')');
074        PRINTABLE_CHARS.set('*');
075        PRINTABLE_CHARS.set('+');
076        PRINTABLE_CHARS.set(',');
077        PRINTABLE_CHARS.set('-');
078        PRINTABLE_CHARS.set('.');
079        PRINTABLE_CHARS.set('/');
080        for (int i = '0'; i <= '9'; i++) {
081            PRINTABLE_CHARS.set(i);
082        }
083        PRINTABLE_CHARS.set(':');
084        PRINTABLE_CHARS.set(';');
085        PRINTABLE_CHARS.set('<');
086        PRINTABLE_CHARS.set('>');
087        PRINTABLE_CHARS.set('@');
088        for (int i = 'A'; i <= 'Z'; i++) {
089            PRINTABLE_CHARS.set(i);
090        }
091        PRINTABLE_CHARS.set('[');
092        PRINTABLE_CHARS.set('\\');
093        PRINTABLE_CHARS.set(']');
094        PRINTABLE_CHARS.set('^');
095        PRINTABLE_CHARS.set('`');
096        for (int i = 'a'; i <= 'z'; i++) {
097            PRINTABLE_CHARS.set(i);
098        }
099        PRINTABLE_CHARS.set('{');
100        PRINTABLE_CHARS.set('|');
101        PRINTABLE_CHARS.set('}');
102        PRINTABLE_CHARS.set('~');
103    }
104
105    private static final byte UNDERSCORE = 95;
106
107    private boolean encodeBlanks;
108
109    /**
110     * Constructs a new instance.
111     */
112    public QCodec() {
113        this(StandardCharsets.UTF_8);
114    }
115
116    /**
117     * Constructs a new instance for the selection of a default Charset.
118     *
119     * @param charset
120     *            the default string Charset to use.
121     *
122     * @see Charset
123     * @since 1.7
124     */
125    public QCodec(final Charset charset) {
126        super(charset);
127    }
128
129    /**
130     * Constructs a new instance for the selection of a default Charset.
131     *
132     * @param charsetName
133     *            the Charset to use.
134     * @throws java.nio.charset.UnsupportedCharsetException
135     *             Thrown if the named Charset is unavailable.
136     * @since 1.7 throws UnsupportedCharsetException if the named Charset is unavailable
137     * @see Charset
138     */
139    public QCodec(final String charsetName) {
140        this(Charset.forName(charsetName));
141    }
142
143    /**
144     * Decodes a quoted-printable object into its original form. Escaped characters are converted back to their original
145     * representation.
146     *
147     * @param obj
148     *            quoted-printable object to convert into its original form.
149     * @return original object.
150     * @throws DecoderException
151     *             Thrown if the argument is not a {@code String}. Thrown if a failure condition is encountered
152     *             during the decode process.
153     */
154    @Override
155    public Object decode(final Object obj) throws DecoderException {
156        if (obj == null) {
157            return null;
158        }
159        if (obj instanceof String) {
160            return decode((String) obj);
161        }
162        throw new DecoderException("Objects of type " + obj.getClass().getName() + " cannot be decoded using Q codec");
163    }
164
165    /**
166     * Decodes a quoted-printable string into its original form. Escaped characters are converted back to their original
167     * representation.
168     *
169     * <p>
170     * Uses {@link QuotedPrintableCodec#decodeQuotedPrintable(byte[])} to decode the encoded text. Since 1.23.0, unescaped CR and LF bytes in malformed
171     * encoded words are preserved rather than discarded, and {@code =CR} without a following LF is rejected. This lenient handling does not make such
172     * encoded words valid under RFC 2047.
173     * </p>
174     *
175     * @param str
176     *            quoted-printable string to convert into its original form.
177     * @return original string.
178     * @throws DecoderException
179     *             Thrown if a failure condition is encountered during the decoding process.
180     */
181    @Override
182    public String decode(final String str) throws DecoderException {
183        try {
184            return decodeText(str);
185        } catch (final UnsupportedEncodingException e) {
186            throw new DecoderException(e.getMessage(), e);
187        }
188    }
189
190    @Override
191    protected byte[] doDecoding(final byte[] bytes) throws DecoderException {
192        if (bytes == null) {
193            return null;
194        }
195        boolean hasUnderscores = false;
196        for (final byte b : bytes) {
197            if (b == UNDERSCORE) {
198                hasUnderscores = true;
199                break;
200            }
201        }
202        if (hasUnderscores) {
203            final byte[] tmp = new byte[bytes.length];
204            for (int i = 0; i < bytes.length; i++) {
205                final byte b = bytes[i];
206                if (b != UNDERSCORE) {
207                    tmp[i] = b;
208                } else {
209                    tmp[i] = Utils.SPACE;
210                }
211            }
212            return QuotedPrintableCodec.decodeQuotedPrintable(tmp);
213        }
214        return QuotedPrintableCodec.decodeQuotedPrintable(bytes);
215    }
216
217    @Override
218    protected byte[] doEncoding(final byte[] bytes) {
219        if (bytes == null) {
220            return null;
221        }
222        final byte[] data = QuotedPrintableCodec.encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
223        if (this.encodeBlanks) {
224            for (int i = 0; i < data.length; i++) {
225                if (data[i] == Utils.SPACE) {
226                    data[i] = UNDERSCORE;
227                }
228            }
229        }
230        return data;
231    }
232
233    /**
234     * Encodes an object into its quoted-printable form using the default Charset. Unsafe characters are escaped.
235     *
236     * @param obj
237     *            object to convert to quoted-printable form.
238     * @return quoted-printable object.
239     * @throws EncoderException
240     *             Thrown if a failure condition is encountered during the encoding process.
241     */
242    @Override
243    public Object encode(final Object obj) throws EncoderException {
244        if (obj == null) {
245            return null;
246        }
247        if (obj instanceof String) {
248            return encode((String) obj);
249        }
250        throw new EncoderException("Objects of type " + obj.getClass().getName() + " cannot be encoded using Q codec");
251    }
252
253    /**
254     * Encodes a string into its quoted-printable form using the default Charset. Unsafe characters are escaped.
255     *
256     * @param sourceStr
257     *            string to convert to quoted-printable form.
258     * @return quoted-printable string.
259     * @throws EncoderException
260     *             Thrown if a failure condition is encountered during the encoding process.
261     */
262    @Override
263    public String encode(final String sourceStr) throws EncoderException {
264        return encode(sourceStr, getCharset());
265    }
266
267    /**
268     * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
269     *
270     * @param sourceStr
271     *            string to convert to quoted-printable form.
272     * @param sourceCharset
273     *            the Charset for sourceStr.
274     * @return quoted-printable string.
275     * @throws EncoderException
276     *             Thrown if a failure condition is encountered during the encoding process.
277     * @since 1.7
278     */
279    public String encode(final String sourceStr, final Charset sourceCharset) throws EncoderException {
280        return encodeText(sourceStr, sourceCharset);
281    }
282
283    /**
284     * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
285     *
286     * @param sourceStr
287     *            string to convert to quoted-printable form.
288     * @param sourceCharset
289     *            the Charset for sourceStr.
290     * @return quoted-printable string.
291     * @throws EncoderException
292     *             Thrown if a failure condition is encountered during the encoding process.
293     */
294    public String encode(final String sourceStr, final String sourceCharset) throws EncoderException {
295        try {
296            return encodeText(sourceStr, sourceCharset);
297        } catch (final UnsupportedCharsetException e) {
298            throw new EncoderException(e.getMessage(), e);
299        }
300    }
301
302    @Override
303    protected String getEncoding() {
304        return "Q";
305    }
306
307    /**
308     * Tests whether the optional transformation of SPACE characters is to be used.
309     *
310     * @return {@code true} if SPACE characters are to be transformed, {@code false} otherwise.
311     */
312    public boolean isEncodeBlanks() {
313        return this.encodeBlanks;
314    }
315
316    /**
317     * Sets whether the optional transformation of SPACE characters is to be used.
318     *
319     * @param b
320     *            {@code true} if SPACE characters are to be transformed, {@code false} otherwise.
321     */
322    public void setEncodeBlanks(final boolean b) {
323        this.encodeBlanks = b;
324    }
325}