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