1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.codec.net;
19
20 import java.io.UnsupportedEncodingException;
21 import java.nio.charset.Charset;
22 import java.nio.charset.StandardCharsets;
23 import java.nio.charset.UnsupportedCharsetException;
24 import java.util.BitSet;
25
26 import org.apache.commons.codec.DecoderException;
27 import org.apache.commons.codec.EncoderException;
28 import org.apache.commons.codec.StringDecoder;
29 import org.apache.commons.codec.StringEncoder;
30
31 /**
32 * Similar to the Quoted-Printable content-transfer-encoding defined in
33 * <a href="http://www.ietf.org/rfc/rfc1521.txt">RFC 1521</a> and designed to allow text containing mostly ASCII
34 * characters to be decipherable on an ASCII terminal without decoding.
35 * <p>
36 * <a href="http://www.ietf.org/rfc/rfc1522.txt">RFC 1522</a> describes techniques to allow the encoding of non-ASCII
37 * text in various portions of a RFC 822 [2] message header, in a manner which is unlikely to confuse existing message
38 * handling software.
39 * </p>
40 * <p>
41 * This class is conditionally thread-safe.
42 * The instance field for encoding blanks is mutable {@link #setEncodeBlanks(boolean)}
43 * but is not volatile, and accesses are not synchronized.
44 * If an instance of the class is shared between threads, the caller needs to ensure that suitable synchronization
45 * is used to ensure safe publication of the value between threads, and must not invoke
46 * {@link #setEncodeBlanks(boolean)} after initial setup.
47 * </p>
48 *
49 * @see <a href="http://www.ietf.org/rfc/rfc1522.txt">MIME (Multipurpose Internet Mail Extensions) Part Two: Message
50 * Header Extensions for Non-ASCII Text</a>
51 *
52 * @since 1.3
53 */
54 public class QCodec extends RFC1522Codec implements StringEncoder, StringDecoder {
55 /**
56 * BitSet of printable characters as defined in RFC 1522.
57 */
58 private static final BitSet PRINTABLE_CHARS = new BitSet(256);
59
60 // Static initializer for printable chars collection
61 static {
62 // alpha characters
63 PRINTABLE_CHARS.set(' ');
64 PRINTABLE_CHARS.set('!');
65 PRINTABLE_CHARS.set('"');
66 PRINTABLE_CHARS.set('#');
67 PRINTABLE_CHARS.set('$');
68 PRINTABLE_CHARS.set('%');
69 PRINTABLE_CHARS.set('&');
70 PRINTABLE_CHARS.set('\'');
71 PRINTABLE_CHARS.set('(');
72 PRINTABLE_CHARS.set(')');
73 PRINTABLE_CHARS.set('*');
74 PRINTABLE_CHARS.set('+');
75 PRINTABLE_CHARS.set(',');
76 PRINTABLE_CHARS.set('-');
77 PRINTABLE_CHARS.set('.');
78 PRINTABLE_CHARS.set('/');
79 for (int i = '0'; i <= '9'; i++) {
80 PRINTABLE_CHARS.set(i);
81 }
82 PRINTABLE_CHARS.set(':');
83 PRINTABLE_CHARS.set(';');
84 PRINTABLE_CHARS.set('<');
85 PRINTABLE_CHARS.set('>');
86 PRINTABLE_CHARS.set('@');
87 for (int i = 'A'; i <= 'Z'; i++) {
88 PRINTABLE_CHARS.set(i);
89 }
90 PRINTABLE_CHARS.set('[');
91 PRINTABLE_CHARS.set('\\');
92 PRINTABLE_CHARS.set(']');
93 PRINTABLE_CHARS.set('^');
94 PRINTABLE_CHARS.set('`');
95 for (int i = 'a'; i <= 'z'; i++) {
96 PRINTABLE_CHARS.set(i);
97 }
98 PRINTABLE_CHARS.set('{');
99 PRINTABLE_CHARS.set('|');
100 PRINTABLE_CHARS.set('}');
101 PRINTABLE_CHARS.set('~');
102 }
103 private static final byte SPACE = 32;
104
105 private static final byte UNDERSCORE = 95;
106
107 private boolean encodeBlanks;
108
109 /**
110 * Default constructor.
111 */
112 public QCodec() {
113 this(StandardCharsets.UTF_8);
114 }
115
116 /**
117 * Constructor which allows 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 * Constructor which allows for the selection of a default Charset.
131 *
132 * @param charsetName
133 * the Charset to use.
134 * @throws java.nio.charset.UnsupportedCharsetException
135 * 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 * @param str
170 * quoted-printable string to convert into its original form
171 * @return original string
172 * @throws DecoderException
173 * A decoder exception is thrown if a failure condition is encountered during the decode process.
174 */
175 @Override
176 public String decode(final String str) throws DecoderException {
177 try {
178 return decodeText(str);
179 } catch (final UnsupportedEncodingException e) {
180 throw new DecoderException(e.getMessage(), e);
181 }
182 }
183
184 @Override
185 protected byte[] doDecoding(final byte[] bytes) throws DecoderException {
186 if (bytes == null) {
187 return null;
188 }
189 boolean hasUnderscores = false;
190 for (final byte b : bytes) {
191 if (b == UNDERSCORE) {
192 hasUnderscores = true;
193 break;
194 }
195 }
196 if (hasUnderscores) {
197 final byte[] tmp = new byte[bytes.length];
198 for (int i = 0; i < bytes.length; i++) {
199 final byte b = bytes[i];
200 if (b != UNDERSCORE) {
201 tmp[i] = b;
202 } else {
203 tmp[i] = SPACE;
204 }
205 }
206 return QuotedPrintableCodec.decodeQuotedPrintable(tmp);
207 }
208 return QuotedPrintableCodec.decodeQuotedPrintable(bytes);
209 }
210
211 @Override
212 protected byte[] doEncoding(final byte[] bytes) {
213 if (bytes == null) {
214 return null;
215 }
216 final byte[] data = QuotedPrintableCodec.encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
217 if (this.encodeBlanks) {
218 for (int i = 0; i < data.length; i++) {
219 if (data[i] == SPACE) {
220 data[i] = UNDERSCORE;
221 }
222 }
223 }
224 return data;
225 }
226
227 /**
228 * Encodes an object into its quoted-printable form using the default Charset. Unsafe characters are escaped.
229 *
230 * @param obj
231 * object to convert to quoted-printable form
232 * @return quoted-printable object
233 * @throws EncoderException
234 * thrown if a failure condition is encountered during the encoding process.
235 */
236 @Override
237 public Object encode(final Object obj) throws EncoderException {
238 if (obj == null) {
239 return null;
240 }
241 if (obj instanceof String) {
242 return encode((String) obj);
243 }
244 throw new EncoderException("Objects of type " + obj.getClass().getName() + " cannot be encoded using Q codec");
245 }
246
247 /**
248 * Encodes a string into its quoted-printable form using the default Charset. Unsafe characters are escaped.
249 *
250 * @param sourceStr
251 * string to convert to quoted-printable form
252 * @return quoted-printable string
253 * @throws EncoderException
254 * thrown if a failure condition is encountered during the encoding process.
255 */
256 @Override
257 public String encode(final String sourceStr) throws EncoderException {
258 return encode(sourceStr, getCharset());
259 }
260
261 /**
262 * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
263 *
264 * @param sourceStr
265 * string to convert to quoted-printable form
266 * @param sourceCharset
267 * the Charset for sourceStr
268 * @return quoted-printable string
269 * @throws EncoderException
270 * thrown if a failure condition is encountered during the encoding process.
271 * @since 1.7
272 */
273 public String encode(final String sourceStr, final Charset sourceCharset) throws EncoderException {
274 return encodeText(sourceStr, sourceCharset);
275 }
276
277 /**
278 * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
279 *
280 * @param sourceStr
281 * string to convert to quoted-printable form
282 * @param sourceCharset
283 * the Charset for sourceStr
284 * @return quoted-printable string
285 * @throws EncoderException
286 * thrown if a failure condition is encountered during the encoding process.
287 */
288 public String encode(final String sourceStr, final String sourceCharset) throws EncoderException {
289 try {
290 return encodeText(sourceStr, sourceCharset);
291 } catch (final UnsupportedCharsetException e) {
292 throw new EncoderException(e.getMessage(), e);
293 }
294 }
295
296 @Override
297 protected String getEncoding() {
298 return "Q";
299 }
300
301 /**
302 * Tests if optional transformation of SPACE characters is to be used
303 *
304 * @return {@code true} if SPACE characters are to be transformed, {@code false} otherwise
305 */
306 public boolean isEncodeBlanks() {
307 return this.encodeBlanks;
308 }
309
310 /**
311 * Defines whether optional transformation of SPACE characters is to be used
312 *
313 * @param b
314 * {@code true} if SPACE characters are to be transformed, {@code false} otherwise
315 */
316 public void setEncodeBlanks(final boolean b) {
317 this.encodeBlanks = b;
318 }
319 }