1 package org.codehaus.plexus.util;
2
3 /*
4 * Copyright The Codehaus Foundation.
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 /**
20 * Provides Base64 encoding and decoding as defined by RFC 2045.
21 * <p>
22 * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
23 * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
24 * </p>
25 *
26 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
27 * @author Apache Software Foundation
28 * @since 1.0-dev
29 *
30 */
31 public class Base64 {
32
33 //
34 // Source Id: Base64.java 161350 2005-04-14 20:39:46Z ggregory
35 //
36
37 /**
38 * Chunk size per RFC 2045 section 6.8.
39 * <p>
40 * The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
41 * equal signs.
42 * </p>
43 *
44 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
45 */
46 static final int CHUNK_SIZE = 76;
47
48 /**
49 * Chunk separator per RFC 2045 section 2.1.
50 *
51 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
52 */
53 static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();
54
55 /**
56 * The base length.
57 */
58 static final int BASELENGTH = 255;
59
60 /**
61 * Lookup length.
62 */
63 static final int LOOKUPLENGTH = 64;
64
65 /**
66 * Used to calculate the number of bits in a byte.
67 */
68 static final int EIGHTBIT = 8;
69
70 /**
71 * Used when encoding something which has fewer than 24 bits.
72 */
73 static final int SIXTEENBIT = 16;
74
75 /**
76 * Used to determine how many bits data contains.
77 */
78 static final int TWENTYFOURBITGROUP = 24;
79
80 /**
81 * Used to get the number of Quadruples.
82 */
83 static final int FOURBYTE = 4;
84
85 /**
86 * Used to test the sign of a byte.
87 */
88 static final int SIGN = -128;
89
90 /**
91 * Byte used to pad output.
92 */
93 static final byte PAD = (byte) '=';
94
95 /**
96 * Contains the Base64 values <code>0</code> through <code>63</code> accessed by using character encodings as
97 * indices.
98 * <p>
99 * For example, <code>base64Alphabet['+']</code> returns <code>62</code>.
100 * </p>
101 * <p>
102 * The value of undefined encodings is <code>-1</code>.
103 * </p>
104 */
105 private static byte[] base64Alphabet = new byte[BASELENGTH];
106
107 /**
108 * <p>
109 * Contains the Base64 encodings <code>A</code> through <code>Z</code>, followed by <code>a</code> through
110 * <code>z</code>, followed by <code>0</code> through <code>9</code>, followed by <code>+</code>, and
111 * <code>/</code>.
112 * </p>
113 * <p>
114 * This array is accessed by using character values as indices.
115 * </p>
116 * <p>
117 * For example, <code>lookUpBase64Alphabet[62] </code> returns <code>'+'</code>.
118 * </p>
119 */
120 private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
121
122 // Populating the lookup and character arrays
123 static {
124 for (int i = 0; i < BASELENGTH; i++) {
125 base64Alphabet[i] = (byte) -1;
126 }
127 for (int i = 'Z'; i >= 'A'; i--) {
128 base64Alphabet[i] = (byte) (i - 'A');
129 }
130 for (int i = 'z'; i >= 'a'; i--) {
131 base64Alphabet[i] = (byte) (i - 'a' + 26);
132 }
133 for (int i = '9'; i >= '0'; i--) {
134 base64Alphabet[i] = (byte) (i - '0' + 52);
135 }
136
137 base64Alphabet['+'] = 62;
138 base64Alphabet['/'] = 63;
139
140 for (int i = 0; i <= 25; i++) {
141 lookUpBase64Alphabet[i] = (byte) ('A' + i);
142 }
143
144 for (int i = 26, j = 0; i <= 51; i++, j++) {
145 lookUpBase64Alphabet[i] = (byte) ('a' + j);
146 }
147
148 for (int i = 52, j = 0; i <= 61; i++, j++) {
149 lookUpBase64Alphabet[i] = (byte) ('0' + j);
150 }
151
152 lookUpBase64Alphabet[62] = (byte) '+';
153 lookUpBase64Alphabet[63] = (byte) '/';
154 }
155
156 /**
157 * Returns whether or not the <code>octect</code> is in the base 64 alphabet.
158 *
159 * @param octect The value to test
160 * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
161 */
162 private static boolean isBase64(byte octect) {
163 if (octect == PAD) {
164 return true;
165 } else if (octect < 0 || base64Alphabet[octect] == -1) {
166 return false;
167 } else {
168 return true;
169 }
170 }
171
172 /**
173 * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
174 *
175 * @param arrayOctect byte array to test
176 * @return <code>true</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
177 * false, otherwise
178 */
179 public static boolean isArrayByteBase64(byte[] arrayOctect) {
180
181 arrayOctect = discardWhitespace(arrayOctect);
182
183 int length = arrayOctect.length;
184 if (length == 0) {
185 // shouldn't a 0 length array be valid base64 data?
186 // return false;
187 return true;
188 }
189 for (byte anArrayOctect : arrayOctect) {
190 if (!isBase64(anArrayOctect)) {
191 return false;
192 }
193 }
194 return true;
195 }
196
197 /**
198 * Encodes binary data using the base64 algorithm but does not chunk the output.
199 *
200 * @param binaryData binary data to encode
201 * @return Base64 characters
202 */
203 public static byte[] encodeBase64(byte[] binaryData) {
204 return encodeBase64(binaryData, false);
205 }
206
207 /**
208 * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
209 *
210 * @param binaryData binary data to encode
211 * @return Base64 characters chunked in 76 character blocks
212 */
213 public static byte[] encodeBase64Chunked(byte[] binaryData) {
214 return encodeBase64(binaryData, true);
215 }
216
217 /**
218 * Decodes a byte[] containing containing characters in the Base64 alphabet.
219 *
220 * @param pArray A byte array containing Base64 character data
221 * @return a byte array containing binary data
222 */
223 public byte[] decode(byte[] pArray) {
224 return decodeBase64(pArray);
225 }
226
227 /**
228 * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
229 *
230 * @param binaryData Array containing binary data to encode.
231 * @param isChunked if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
232 * @return Base64-encoded data.
233 */
234 public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
235 int lengthDataBits = binaryData.length * EIGHTBIT;
236 int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
237 int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
238 byte encodedData[] = null;
239 int encodedDataLength = 0;
240 int nbrChunks = 0;
241
242 if (fewerThan24bits != 0) {
243 // data not divisible by 24 bit
244 encodedDataLength = (numberTriplets + 1) * 4;
245 } else {
246 // 16 or 8 bit
247 encodedDataLength = numberTriplets * 4;
248 }
249
250 // If the output is to be "chunked" into 76 character sections,
251 // for compliance with RFC 2045 MIME, then it is important to
252 // allow for extra length to account for the separator(s)
253 if (isChunked) {
254
255 nbrChunks = (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE));
256 encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
257 }
258
259 encodedData = new byte[encodedDataLength];
260
261 byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
262
263 int encodedIndex = 0;
264 int dataIndex = 0;
265 int i = 0;
266 int nextSeparatorIndex = CHUNK_SIZE;
267 int chunksSoFar = 0;
268
269 // log.debug("number of triplets = " + numberTriplets);
270 for (i = 0; i < numberTriplets; i++) {
271 dataIndex = i * 3;
272 b1 = binaryData[dataIndex];
273 b2 = binaryData[dataIndex + 1];
274 b3 = binaryData[dataIndex + 2];
275
276 // log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3);
277
278 l = (byte) (b2 & 0x0f);
279 k = (byte) (b1 & 0x03);
280
281 byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
282 byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
283 byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);
284
285 encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
286 // log.debug( "val2 = " + val2 );
287 // log.debug( "k4 = " + (k<<4) );
288 // log.debug( "vak = " + (val2 | (k<<4)) );
289 encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
290 encodedData[encodedIndex + 2] = lookUpBase64Alphabet[(l << 2) | val3];
291 encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
292
293 encodedIndex += 4;
294
295 // If we are chunking, let's put a chunk separator down.
296 if (isChunked) {
297 // this assumes that CHUNK_SIZE % 4 == 0
298 if (encodedIndex == nextSeparatorIndex) {
299 System.arraycopy(CHUNK_SEPARATOR, 0, encodedData, encodedIndex, CHUNK_SEPARATOR.length);
300 chunksSoFar++;
301 nextSeparatorIndex = (CHUNK_SIZE * (chunksSoFar + 1)) + (chunksSoFar * CHUNK_SEPARATOR.length);
302 encodedIndex += CHUNK_SEPARATOR.length;
303 }
304 }
305 }
306
307 // form integral number of 6-bit groups
308 dataIndex = i * 3;
309
310 if (fewerThan24bits == EIGHTBIT) {
311 b1 = binaryData[dataIndex];
312 k = (byte) (b1 & 0x03);
313 // log.debug("b1=" + b1);
314 // log.debug("b1<<2 = " + (b1>>2) );
315 byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
316 encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
317 encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
318 encodedData[encodedIndex + 2] = PAD;
319 encodedData[encodedIndex + 3] = PAD;
320 } else if (fewerThan24bits == SIXTEENBIT) {
321
322 b1 = binaryData[dataIndex];
323 b2 = binaryData[dataIndex + 1];
324 l = (byte) (b2 & 0x0f);
325 k = (byte) (b1 & 0x03);
326
327 byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
328 byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
329
330 encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
331 encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
332 encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
333 encodedData[encodedIndex + 3] = PAD;
334 }
335
336 if (isChunked) {
337 // we also add a separator to the end of the final chunk.
338 if (chunksSoFar < nbrChunks) {
339 System.arraycopy(
340 CHUNK_SEPARATOR,
341 0,
342 encodedData,
343 encodedDataLength - CHUNK_SEPARATOR.length,
344 CHUNK_SEPARATOR.length);
345 }
346 }
347
348 return encodedData;
349 }
350
351 /**
352 * Decodes Base64 data into octects
353 *
354 * @param base64Data Byte array containing Base64 data
355 * @return Array containing decoded data.
356 */
357 public static byte[] decodeBase64(byte[] base64Data) {
358 // RFC 2045 requires that we discard ALL non-Base64 characters
359 base64Data = discardNonBase64(base64Data);
360
361 // handle the edge case, so we don't have to worry about it later
362 if (base64Data.length == 0) {
363 return new byte[0];
364 }
365
366 int numberQuadruple = base64Data.length / FOURBYTE;
367 byte decodedData[] = null;
368 byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
369
370 // Throw away anything not in base64Data
371
372 int encodedIndex = 0;
373 int dataIndex = 0;
374 {
375 // this sizes the output array properly - rlw
376 int lastData = base64Data.length;
377 // ignore the '=' padding
378 while (base64Data[lastData - 1] == PAD) {
379 if (--lastData == 0) {
380 return new byte[0];
381 }
382 }
383 decodedData = new byte[lastData - numberQuadruple];
384 }
385
386 for (int i = 0; i < numberQuadruple; i++) {
387 dataIndex = i * 4;
388 marker0 = base64Data[dataIndex + 2];
389 marker1 = base64Data[dataIndex + 3];
390
391 b1 = base64Alphabet[base64Data[dataIndex]];
392 b2 = base64Alphabet[base64Data[dataIndex + 1]];
393
394 if (marker0 != PAD && marker1 != PAD) {
395 // No PAD e.g 3cQl
396 b3 = base64Alphabet[marker0];
397 b4 = base64Alphabet[marker1];
398
399 decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
400 decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
401 decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
402 } else if (marker0 == PAD) {
403 // Two PAD e.g. 3c[Pad][Pad]
404 decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
405 } else if (marker1 == PAD) {
406 // One PAD e.g. 3cQ[Pad]
407 b3 = base64Alphabet[marker0];
408
409 decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
410 decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
411 }
412 encodedIndex += 3;
413 }
414 return decodedData;
415 }
416
417 /**
418 * Discards any whitespace from a base-64 encoded block.
419 *
420 * @param data The base-64 encoded data to discard the whitespace from.
421 * @return The data, less whitespace (see RFC 2045).
422 */
423 static byte[] discardWhitespace(byte[] data) {
424 byte groomedData[] = new byte[data.length];
425 int bytesCopied = 0;
426
427 for (byte aData : data) {
428 switch (aData) {
429 case (byte) ' ':
430 case (byte) '\n':
431 case (byte) '\r':
432 case (byte) '\t':
433 break;
434 default:
435 groomedData[bytesCopied++] = aData;
436 }
437 }
438
439 byte packedData[] = new byte[bytesCopied];
440
441 System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
442
443 return packedData;
444 }
445
446 /**
447 * Discards any characters outside of the base64 alphabet, per the requirements on page 25 of RFC 2045 - "Any
448 * characters outside of the base64 alphabet are to be ignored in base64 encoded data."
449 *
450 * @param data The base-64 encoded data to groom
451 * @return The data, less non-base64 characters (see RFC 2045).
452 */
453 static byte[] discardNonBase64(byte[] data) {
454 byte groomedData[] = new byte[data.length];
455 int bytesCopied = 0;
456
457 for (byte aData : data) {
458 if (isBase64(aData)) {
459 groomedData[bytesCopied++] = aData;
460 }
461 }
462
463 byte packedData[] = new byte[bytesCopied];
464
465 System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
466
467 return packedData;
468 }
469
470 /**
471 * Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
472 *
473 * @param pArray a byte array containing binary data
474 * @return A byte array containing only Base64 character data
475 */
476 public byte[] encode(byte[] pArray) {
477 return encodeBase64(pArray, false);
478 }
479 }