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 * https://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="https://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="https://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="https://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 /**
57 * BitSet of printable characters as defined in RFC 1522.
58 */
59 private static final BitSet PRINTABLE_CHARS = new BitSet(256);
60
61 // Static initializer for printable chars collection
62 static {
63 // alpha characters
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 PRINTABLE_CHARS.set('/');
80 for (int i = '0'; i <= '9'; i++) {
81 PRINTABLE_CHARS.set(i);
82 }
83 PRINTABLE_CHARS.set(':');
84 PRINTABLE_CHARS.set(';');
85 PRINTABLE_CHARS.set('<');
86 PRINTABLE_CHARS.set('>');
87 PRINTABLE_CHARS.set('@');
88 for (int i = 'A'; i <= 'Z'; i++) {
89 PRINTABLE_CHARS.set(i);
90 }
91 PRINTABLE_CHARS.set('[');
92 PRINTABLE_CHARS.set('\\');
93 PRINTABLE_CHARS.set(']');
94 PRINTABLE_CHARS.set('^');
95 PRINTABLE_CHARS.set('`');
96 for (int i = 'a'; i <= 'z'; i++) {
97 PRINTABLE_CHARS.set(i);
98 }
99 PRINTABLE_CHARS.set('{');
100 PRINTABLE_CHARS.set('|');
101 PRINTABLE_CHARS.set('}');
102 PRINTABLE_CHARS.set('~');
103 }
104 private static final byte SPACE = 32;
105
106 private static final byte UNDERSCORE = 95;
107
108 private boolean encodeBlanks;
109
110 /**
111 * Default constructor.
112 */
113 public QCodec() {
114 this(StandardCharsets.UTF_8);
115 }
116
117 /**
118 * Constructor which allows for the selection of a default Charset.
119 *
120 * @param charset
121 * the default string Charset to use.
122 *
123 * @see Charset
124 * @since 1.7
125 */
126 public QCodec(final Charset charset) {
127 super(charset);
128 }
129
130 /**
131 * Constructor which allows for the selection of a default Charset.
132 *
133 * @param charsetName
134 * the Charset to use.
135 * @throws java.nio.charset.UnsupportedCharsetException
136 * If the named Charset is unavailable.
137 * @since 1.7 throws UnsupportedCharsetException if the named Charset is unavailable
138 * @see Charset
139 */
140 public QCodec(final String charsetName) {
141 this(Charset.forName(charsetName));
142 }
143
144 /**
145 * Decodes a quoted-printable object into its original form. Escaped characters are converted back to their original
146 * representation.
147 *
148 * @param obj
149 * quoted-printable object to convert into its original form.
150 * @return original object.
151 * @throws DecoderException
152 * Thrown if the argument is not a {@code String}. Thrown if a failure condition is encountered
153 * during the decode process.
154 */
155 @Override
156 public Object decode(final Object obj) throws DecoderException {
157 if (obj == null) {
158 return null;
159 }
160 if (obj instanceof String) {
161 return decode((String) obj);
162 }
163 throw new DecoderException("Objects of type " + obj.getClass().getName() + " cannot be decoded using Q codec");
164 }
165
166 /**
167 * Decodes a quoted-printable string into its original form. Escaped characters are converted back to their original
168 * representation.
169 *
170 * @param str
171 * quoted-printable string to convert into its original form.
172 * @return original string.
173 * @throws DecoderException
174 * A decoder exception is thrown if a failure condition is encountered during the decode process.
175 */
176 @Override
177 public String decode(final String str) throws DecoderException {
178 try {
179 return decodeText(str);
180 } catch (final UnsupportedEncodingException e) {
181 throw new DecoderException(e.getMessage(), e);
182 }
183 }
184
185 @Override
186 protected byte[] doDecoding(final byte[] bytes) throws DecoderException {
187 if (bytes == null) {
188 return null;
189 }
190 boolean hasUnderscores = false;
191 for (final byte b : bytes) {
192 if (b == UNDERSCORE) {
193 hasUnderscores = true;
194 break;
195 }
196 }
197 if (hasUnderscores) {
198 final byte[] tmp = new byte[bytes.length];
199 for (int i = 0; i < bytes.length; i++) {
200 final byte b = bytes[i];
201 if (b != UNDERSCORE) {
202 tmp[i] = b;
203 } else {
204 tmp[i] = SPACE;
205 }
206 }
207 return QuotedPrintableCodec.decodeQuotedPrintable(tmp);
208 }
209 return QuotedPrintableCodec.decodeQuotedPrintable(bytes);
210 }
211
212 @Override
213 protected byte[] doEncoding(final byte[] bytes) {
214 if (bytes == null) {
215 return null;
216 }
217 final byte[] data = QuotedPrintableCodec.encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
218 if (this.encodeBlanks) {
219 for (int i = 0; i < data.length; i++) {
220 if (data[i] == SPACE) {
221 data[i] = UNDERSCORE;
222 }
223 }
224 }
225 return data;
226 }
227
228 /**
229 * Encodes an object into its quoted-printable form using the default Charset. Unsafe characters are escaped.
230 *
231 * @param obj
232 * object to convert to quoted-printable form.
233 * @return quoted-printable object.
234 * @throws EncoderException
235 * thrown if a failure condition is encountered during the encoding process.
236 */
237 @Override
238 public Object encode(final Object obj) throws EncoderException {
239 if (obj == null) {
240 return null;
241 }
242 if (obj instanceof String) {
243 return encode((String) obj);
244 }
245 throw new EncoderException("Objects of type " + obj.getClass().getName() + " cannot be encoded using Q codec");
246 }
247
248 /**
249 * Encodes a string into its quoted-printable form using the default Charset. Unsafe characters are escaped.
250 *
251 * @param sourceStr
252 * string to convert to quoted-printable form.
253 * @return quoted-printable string.
254 * @throws EncoderException
255 * thrown if a failure condition is encountered during the encoding process.
256 */
257 @Override
258 public String encode(final String sourceStr) throws EncoderException {
259 return encode(sourceStr, getCharset());
260 }
261
262 /**
263 * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
264 *
265 * @param sourceStr
266 * string to convert to quoted-printable form.
267 * @param sourceCharset
268 * the Charset for sourceStr.
269 * @return quoted-printable string.
270 * @throws EncoderException
271 * thrown if a failure condition is encountered during the encoding process.
272 * @since 1.7
273 */
274 public String encode(final String sourceStr, final Charset sourceCharset) throws EncoderException {
275 return encodeText(sourceStr, sourceCharset);
276 }
277
278 /**
279 * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
280 *
281 * @param sourceStr
282 * string to convert to quoted-printable form.
283 * @param sourceCharset
284 * the Charset for sourceStr.
285 * @return quoted-printable string.
286 * @throws EncoderException
287 * thrown if a failure condition is encountered during the encoding process.
288 */
289 public String encode(final String sourceStr, final String sourceCharset) throws EncoderException {
290 try {
291 return encodeText(sourceStr, sourceCharset);
292 } catch (final UnsupportedCharsetException e) {
293 throw new EncoderException(e.getMessage(), e);
294 }
295 }
296
297 @Override
298 protected String getEncoding() {
299 return "Q";
300 }
301
302 /**
303 * Tests if optional transformation of SPACE characters is to be used
304 *
305 * @return {@code true} if SPACE characters are to be transformed, {@code false} otherwise.
306 */
307 public boolean isEncodeBlanks() {
308 return this.encodeBlanks;
309 }
310
311 /**
312 * Defines whether optional transformation of SPACE characters is to be used
313 *
314 * @param b
315 * {@code true} if SPACE characters are to be transformed, {@code false} otherwise.
316 */
317 public void setEncodeBlanks(final boolean b) {
318 this.encodeBlanks = b;
319 }
320 }