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 * http://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
018 package org.apache.commons.codec.binary;
019
020 import java.math.BigInteger;
021
022 /**
023 * Provides Base64 encoding and decoding as defined by <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>.
024 *
025 * <p>
026 * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
027 * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
028 * </p>
029 * <p>
030 * The class can be parameterized in the following manner with various constructors:
031 * <ul>
032 * <li>URL-safe mode: Default off.</li>
033 * <li>Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of
034 * 4 in the encoded data.
035 * <li>Line separator: Default is CRLF ("\r\n")</li>
036 * </ul>
037 * </p>
038 * <p>
039 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only
040 * encode/decode character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252,
041 * UTF-8, etc).
042 * </p>
043 * <p>
044 * This class is thread-safe.
045 * </p>
046 *
047 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
048 * @since 1.0
049 * @version $Id: Base64.html 889935 2013-12-11 05:05:13Z ggregory $
050 */
051 public class Base64 extends BaseNCodec {
052
053 /**
054 * BASE32 characters are 6 bits in length.
055 * They are formed by taking a block of 3 octets to form a 24-bit string,
056 * which is converted into 4 BASE64 characters.
057 */
058 private static final int BITS_PER_ENCODED_BYTE = 6;
059 private static final int BYTES_PER_UNENCODED_BLOCK = 3;
060 private static final int BYTES_PER_ENCODED_BLOCK = 4;
061
062 /**
063 * Chunk separator per RFC 2045 section 2.1.
064 *
065 * <p>
066 * N.B. The next major release may break compatibility and make this field private.
067 * </p>
068 *
069 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
070 */
071 static final byte[] CHUNK_SEPARATOR = {'\r', '\n'};
072
073 /**
074 * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet"
075 * equivalents as specified in Table 1 of RFC 2045.
076 *
077 * Thanks to "commons" project in ws.apache.org for this code.
078 * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
079 */
080 private static final byte[] STANDARD_ENCODE_TABLE = {
081 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
082 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
083 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
084 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
085 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
086 };
087
088 /**
089 * This is a copy of the STANDARD_ENCODE_TABLE above, but with + and /
090 * changed to - and _ to make the encoded Base64 results more URL-SAFE.
091 * This table is only used when the Base64's mode is set to URL-SAFE.
092 */
093 private static final byte[] URL_SAFE_ENCODE_TABLE = {
094 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
095 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
096 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
097 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
098 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'
099 };
100
101 /**
102 * This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified
103 * in Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64
104 * alphabet but fall within the bounds of the array are translated to -1.
105 *
106 * Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both
107 * URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit).
108 *
109 * Thanks to "commons" project in ws.apache.org for this code.
110 * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
111 */
112 private static final byte[] DECODE_TABLE = {
113 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
114 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
115 -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, 52, 53, 54,
116 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4,
117 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
118 24, 25, -1, -1, -1, -1, 63, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34,
119 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
120 };
121
122 /**
123 * Base64 uses 6-bit fields.
124 */
125 /** Mask used to extract 6 bits, used when encoding */
126 private static final int MASK_6BITS = 0x3f;
127
128 // The static final fields above are used for the original static byte[] methods on Base64.
129 // The private member fields below are used with the new streaming approach, which requires
130 // some state be preserved between calls of encode() and decode().
131
132 /**
133 * Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able
134 * to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch
135 * between the two modes.
136 */
137 private final byte[] encodeTable;
138
139 // Only one decode table currently; keep for consistency with Base32 code
140 private final byte[] decodeTable = DECODE_TABLE;
141
142 /**
143 * Line separator for encoding. Not used when decoding. Only used if lineLength > 0.
144 */
145 private final byte[] lineSeparator;
146
147 /**
148 * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
149 * <code>decodeSize = 3 + lineSeparator.length;</code>
150 */
151 private final int decodeSize;
152
153 /**
154 * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
155 * <code>encodeSize = 4 + lineSeparator.length;</code>
156 */
157 private final int encodeSize;
158
159 /**
160 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
161 * <p>
162 * When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE.
163 * </p>
164 *
165 * <p>
166 * When decoding all variants are supported.
167 * </p>
168 */
169 public Base64() {
170 this(0);
171 }
172
173 /**
174 * Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
175 * <p>
176 * When encoding the line length is 76, the line separator is CRLF, and the encoding table is
177 * STANDARD_ENCODE_TABLE.
178 * </p>
179 *
180 * <p>
181 * When decoding all variants are supported.
182 * </p>
183 *
184 * @param urlSafe
185 * if {@code true}, URL-safe encoding is used. In most cases this should be set to {@code false}.
186 * @since 1.4
187 */
188 public Base64(final boolean urlSafe) {
189 this(MIME_CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);
190 }
191
192 /**
193 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
194 * <p>
195 * When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is
196 * STANDARD_ENCODE_TABLE.
197 * </p>
198 * <p>
199 * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
200 * </p>
201 * <p>
202 * When decoding all variants are supported.
203 * </p>
204 *
205 * @param lineLength
206 * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
207 * 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when
208 * decoding.
209 * @since 1.4
210 */
211 public Base64(final int lineLength) {
212 this(lineLength, CHUNK_SEPARATOR);
213 }
214
215 /**
216 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
217 * <p>
218 * When encoding the line length and line separator are given in the constructor, and the encoding table is
219 * STANDARD_ENCODE_TABLE.
220 * </p>
221 * <p>
222 * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
223 * </p>
224 * <p>
225 * When decoding all variants are supported.
226 * </p>
227 *
228 * @param lineLength
229 * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
230 * 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when
231 * decoding.
232 * @param lineSeparator
233 * Each line of encoded data will end with this sequence of bytes.
234 * @throws IllegalArgumentException
235 * Thrown when the provided lineSeparator included some base64 characters.
236 * @since 1.4
237 */
238 public Base64(final int lineLength, final byte[] lineSeparator) {
239 this(lineLength, lineSeparator, false);
240 }
241
242 /**
243 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
244 * <p>
245 * When encoding the line length and line separator are given in the constructor, and the encoding table is
246 * STANDARD_ENCODE_TABLE.
247 * </p>
248 * <p>
249 * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
250 * </p>
251 * <p>
252 * When decoding all variants are supported.
253 * </p>
254 *
255 * @param lineLength
256 * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
257 * 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when
258 * decoding.
259 * @param lineSeparator
260 * Each line of encoded data will end with this sequence of bytes.
261 * @param urlSafe
262 * Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode
263 * operations. Decoding seamlessly handles both modes.
264 * <b>Note: no padding is added when using the URL-safe alphabet.</b>
265 * @throws IllegalArgumentException
266 * The provided lineSeparator included some base64 characters. That's not going to work!
267 * @since 1.4
268 */
269 public Base64(final int lineLength, final byte[] lineSeparator, final boolean urlSafe) {
270 super(BYTES_PER_UNENCODED_BLOCK, BYTES_PER_ENCODED_BLOCK,
271 lineLength,
272 lineSeparator == null ? 0 : lineSeparator.length);
273 // TODO could be simplified if there is no requirement to reject invalid line sep when length <=0
274 // @see test case Base64Test.testConstructors()
275 if (lineSeparator != null) {
276 if (containsAlphabetOrPad(lineSeparator)) {
277 final String sep = StringUtils.newStringUtf8(lineSeparator);
278 throw new IllegalArgumentException("lineSeparator must not contain base64 characters: [" + sep + "]");
279 }
280 if (lineLength > 0){ // null line-sep forces no chunking rather than throwing IAE
281 this.encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length;
282 this.lineSeparator = new byte[lineSeparator.length];
283 System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
284 } else {
285 this.encodeSize = BYTES_PER_ENCODED_BLOCK;
286 this.lineSeparator = null;
287 }
288 } else {
289 this.encodeSize = BYTES_PER_ENCODED_BLOCK;
290 this.lineSeparator = null;
291 }
292 this.decodeSize = this.encodeSize - 1;
293 this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;
294 }
295
296 /**
297 * Returns our current encode mode. True if we're URL-SAFE, false otherwise.
298 *
299 * @return true if we're in URL-SAFE mode, false otherwise.
300 * @since 1.4
301 */
302 public boolean isUrlSafe() {
303 return this.encodeTable == URL_SAFE_ENCODE_TABLE;
304 }
305
306 /**
307 * <p>
308 * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with
309 * the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, to flush last
310 * remaining bytes (if not multiple of 3).
311 * </p>
312 * <p><b>Note: no padding is added when encoding using the URL-safe alphabet.</b></p>
313 * <p>
314 * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
315 * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
316 * </p>
317 *
318 * @param in
319 * byte[] array of binary data to base64 encode.
320 * @param inPos
321 * Position to start reading data from.
322 * @param inAvail
323 * Amount of bytes available from input for encoding.
324 * @param context
325 * the context to be used
326 */
327 @Override
328 void encode(final byte[] in, int inPos, final int inAvail, final Context context) {
329 if (context.eof) {
330 return;
331 }
332 // inAvail < 0 is how we're informed of EOF in the underlying data we're
333 // encoding.
334 if (inAvail < 0) {
335 context.eof = true;
336 if (0 == context.modulus && lineLength == 0) {
337 return; // no leftovers to process and not using chunking
338 }
339 final byte[] buffer = ensureBufferSize(encodeSize, context);
340 final int savedPos = context.pos;
341 switch (context.modulus) { // 0-2
342 case 0 : // nothing to do here
343 break;
344 case 1 : // 8 bits = 6 + 2
345 // top 6 bits:
346 buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 2) & MASK_6BITS];
347 // remaining 2:
348 buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 4) & MASK_6BITS];
349 // URL-SAFE skips the padding to further reduce size.
350 if (encodeTable == STANDARD_ENCODE_TABLE) {
351 buffer[context.pos++] = PAD;
352 buffer[context.pos++] = PAD;
353 }
354 break;
355
356 case 2 : // 16 bits = 6 + 6 + 4
357 buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 10) & MASK_6BITS];
358 buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 4) & MASK_6BITS];
359 buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 2) & MASK_6BITS];
360 // URL-SAFE skips the padding to further reduce size.
361 if (encodeTable == STANDARD_ENCODE_TABLE) {
362 buffer[context.pos++] = PAD;
363 }
364 break;
365 default:
366 throw new IllegalStateException("Impossible modulus "+context.modulus);
367 }
368 context.currentLinePos += context.pos - savedPos; // keep track of current line position
369 // if currentPos == 0 we are at the start of a line, so don't add CRLF
370 if (lineLength > 0 && context.currentLinePos > 0) {
371 System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length);
372 context.pos += lineSeparator.length;
373 }
374 } else {
375 for (int i = 0; i < inAvail; i++) {
376 final byte[] buffer = ensureBufferSize(encodeSize, context);
377 context.modulus = (context.modulus+1) % BYTES_PER_UNENCODED_BLOCK;
378 int b = in[inPos++];
379 if (b < 0) {
380 b += 256;
381 }
382 context.ibitWorkArea = (context.ibitWorkArea << 8) + b; // BITS_PER_BYTE
383 if (0 == context.modulus) { // 3 bytes = 24 bits = 4 * 6 bits to extract
384 buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 18) & MASK_6BITS];
385 buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 12) & MASK_6BITS];
386 buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 6) & MASK_6BITS];
387 buffer[context.pos++] = encodeTable[context.ibitWorkArea & MASK_6BITS];
388 context.currentLinePos += BYTES_PER_ENCODED_BLOCK;
389 if (lineLength > 0 && lineLength <= context.currentLinePos) {
390 System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length);
391 context.pos += lineSeparator.length;
392 context.currentLinePos = 0;
393 }
394 }
395 }
396 }
397 }
398
399 /**
400 * <p>
401 * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once
402 * with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1"
403 * call is not necessary when decoding, but it doesn't hurt, either.
404 * </p>
405 * <p>
406 * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are
407 * silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in,
408 * garbage-out philosophy: it will not check the provided data for validity.
409 * </p>
410 * <p>
411 * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
412 * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
413 * </p>
414 *
415 * @param in
416 * byte[] array of ascii data to base64 decode.
417 * @param inPos
418 * Position to start reading data from.
419 * @param inAvail
420 * Amount of bytes available from input for encoding.
421 * @param context
422 * the context to be used
423 */
424 @Override
425 void decode(final byte[] in, int inPos, final int inAvail, final Context context) {
426 if (context.eof) {
427 return;
428 }
429 if (inAvail < 0) {
430 context.eof = true;
431 }
432 for (int i = 0; i < inAvail; i++) {
433 final byte[] buffer = ensureBufferSize(decodeSize, context);
434 final byte b = in[inPos++];
435 if (b == PAD) {
436 // We're done.
437 context.eof = true;
438 break;
439 } else {
440 if (b >= 0 && b < DECODE_TABLE.length) {
441 final int result = DECODE_TABLE[b];
442 if (result >= 0) {
443 context.modulus = (context.modulus+1) % BYTES_PER_ENCODED_BLOCK;
444 context.ibitWorkArea = (context.ibitWorkArea << BITS_PER_ENCODED_BYTE) + result;
445 if (context.modulus == 0) {
446 buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 16) & MASK_8BITS);
447 buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);
448 buffer[context.pos++] = (byte) (context.ibitWorkArea & MASK_8BITS);
449 }
450 }
451 }
452 }
453 }
454
455 // Two forms of EOF as far as base64 decoder is concerned: actual
456 // EOF (-1) and first time '=' character is encountered in stream.
457 // This approach makes the '=' padding characters completely optional.
458 if (context.eof && context.modulus != 0) {
459 final byte[] buffer = ensureBufferSize(decodeSize, context);
460
461 // We have some spare bits remaining
462 // Output all whole multiples of 8 bits and ignore the rest
463 switch (context.modulus) {
464 // case 0 : // impossible, as excluded above
465 case 1 : // 6 bits - ignore entirely
466 // TODO not currently tested; perhaps it is impossible?
467 break;
468 case 2 : // 12 bits = 8 + 4
469 context.ibitWorkArea = context.ibitWorkArea >> 4; // dump the extra 4 bits
470 buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);
471 break;
472 case 3 : // 18 bits = 8 + 8 + 2
473 context.ibitWorkArea = context.ibitWorkArea >> 2; // dump 2 bits
474 buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);
475 buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);
476 break;
477 default:
478 throw new IllegalStateException("Impossible modulus "+context.modulus);
479 }
480 }
481 }
482
483 /**
484 * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the
485 * method treats whitespace as valid.
486 *
487 * @param arrayOctet
488 * byte array to test
489 * @return {@code true} if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
490 * {@code false}, otherwise
491 * @deprecated 1.5 Use {@link #isBase64(byte[])}, will be removed in 2.0.
492 */
493 @Deprecated
494 public static boolean isArrayByteBase64(final byte[] arrayOctet) {
495 return isBase64(arrayOctet);
496 }
497
498 /**
499 * Returns whether or not the <code>octet</code> is in the base 64 alphabet.
500 *
501 * @param octet
502 * The value to test
503 * @return {@code true} if the value is defined in the the base 64 alphabet, {@code false} otherwise.
504 * @since 1.4
505 */
506 public static boolean isBase64(final byte octet) {
507 return octet == PAD_DEFAULT || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1);
508 }
509
510 /**
511 * Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the
512 * method treats whitespace as valid.
513 *
514 * @param base64
515 * String to test
516 * @return {@code true} if all characters in the String are valid characters in the Base64 alphabet or if
517 * the String is empty; {@code false}, otherwise
518 * @since 1.5
519 */
520 public static boolean isBase64(final String base64) {
521 return isBase64(StringUtils.getBytesUtf8(base64));
522 }
523
524 /**
525 * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the
526 * method treats whitespace as valid.
527 *
528 * @param arrayOctet
529 * byte array to test
530 * @return {@code true} if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
531 * {@code false}, otherwise
532 * @since 1.5
533 */
534 public static boolean isBase64(final byte[] arrayOctet) {
535 for (int i = 0; i < arrayOctet.length; i++) {
536 if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) {
537 return false;
538 }
539 }
540 return true;
541 }
542
543 /**
544 * Encodes binary data using the base64 algorithm but does not chunk the output.
545 *
546 * @param binaryData
547 * binary data to encode
548 * @return byte[] containing Base64 characters in their UTF-8 representation.
549 */
550 public static byte[] encodeBase64(final byte[] binaryData) {
551 return encodeBase64(binaryData, false);
552 }
553
554 /**
555 * Encodes binary data using the base64 algorithm but does not chunk the output.
556 *
557 * NOTE: We changed the behaviour of this method from multi-line chunking (commons-codec-1.4) to
558 * single-line non-chunking (commons-codec-1.5).
559 *
560 * @param binaryData
561 * binary data to encode
562 * @return String containing Base64 characters.
563 * @since 1.4 (NOTE: 1.4 chunked the output, whereas 1.5 does not).
564 */
565 public static String encodeBase64String(final byte[] binaryData) {
566 return StringUtils.newStringUtf8(encodeBase64(binaryData, false));
567 }
568
569 /**
570 * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
571 * url-safe variation emits - and _ instead of + and / characters.
572 * <b>Note: no padding is added.</b>
573 * @param binaryData
574 * binary data to encode
575 * @return byte[] containing Base64 characters in their UTF-8 representation.
576 * @since 1.4
577 */
578 public static byte[] encodeBase64URLSafe(final byte[] binaryData) {
579 return encodeBase64(binaryData, false, true);
580 }
581
582 /**
583 * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
584 * url-safe variation emits - and _ instead of + and / characters.
585 * <b>Note: no padding is added.</b>
586 * @param binaryData
587 * binary data to encode
588 * @return String containing Base64 characters
589 * @since 1.4
590 */
591 public static String encodeBase64URLSafeString(final byte[] binaryData) {
592 return StringUtils.newStringUtf8(encodeBase64(binaryData, false, true));
593 }
594
595 /**
596 * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
597 *
598 * @param binaryData
599 * binary data to encode
600 * @return Base64 characters chunked in 76 character blocks
601 */
602 public static byte[] encodeBase64Chunked(final byte[] binaryData) {
603 return encodeBase64(binaryData, true);
604 }
605
606 /**
607 * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
608 *
609 * @param binaryData
610 * Array containing binary data to encode.
611 * @param isChunked
612 * if {@code true} this encoder will chunk the base64 output into 76 character blocks
613 * @return Base64-encoded data.
614 * @throws IllegalArgumentException
615 * Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
616 */
617 public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked) {
618 return encodeBase64(binaryData, isChunked, false);
619 }
620
621 /**
622 * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
623 *
624 * @param binaryData
625 * Array containing binary data to encode.
626 * @param isChunked
627 * if {@code true} this encoder will chunk the base64 output into 76 character blocks
628 * @param urlSafe
629 * if {@code true} this encoder will emit - and _ instead of the usual + and / characters.
630 * <b>Note: no padding is added when encoding using the URL-safe alphabet.</b>
631 * @return Base64-encoded data.
632 * @throws IllegalArgumentException
633 * Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
634 * @since 1.4
635 */
636 public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe) {
637 return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);
638 }
639
640 /**
641 * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
642 *
643 * @param binaryData
644 * Array containing binary data to encode.
645 * @param isChunked
646 * if {@code true} this encoder will chunk the base64 output into 76 character blocks
647 * @param urlSafe
648 * if {@code true} this encoder will emit - and _ instead of the usual + and / characters.
649 * <b>Note: no padding is added when encoding using the URL-safe alphabet.</b>
650 * @param maxResultSize
651 * The maximum result size to accept.
652 * @return Base64-encoded data.
653 * @throws IllegalArgumentException
654 * Thrown when the input array needs an output array bigger than maxResultSize
655 * @since 1.4
656 */
657 public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked,
658 final boolean urlSafe, final int maxResultSize) {
659 if (binaryData == null || binaryData.length == 0) {
660 return binaryData;
661 }
662
663 // Create this so can use the super-class method
664 // Also ensures that the same roundings are performed by the ctor and the code
665 final Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);
666 final long len = b64.getEncodedLength(binaryData);
667 if (len > maxResultSize) {
668 throw new IllegalArgumentException("Input array too big, the output array would be bigger (" +
669 len +
670 ") than the specified maximum size of " +
671 maxResultSize);
672 }
673
674 return b64.encode(binaryData);
675 }
676
677 /**
678 * Decodes a Base64 String into octets
679 *
680 * @param base64String
681 * String containing Base64 data
682 * @return Array containing decoded data.
683 * @since 1.4
684 */
685 public static byte[] decodeBase64(final String base64String) {
686 return new Base64().decode(base64String);
687 }
688
689 /**
690 * Decodes Base64 data into octets
691 *
692 * @param base64Data
693 * Byte array containing Base64 data
694 * @return Array containing decoded data.
695 */
696 public static byte[] decodeBase64(final byte[] base64Data) {
697 return new Base64().decode(base64Data);
698 }
699
700 // Implementation of the Encoder Interface
701
702 // Implementation of integer encoding used for crypto
703 /**
704 * Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
705 *
706 * @param pArray
707 * a byte array containing base64 character data
708 * @return A BigInteger
709 * @since 1.4
710 */
711 public static BigInteger decodeInteger(final byte[] pArray) {
712 return new BigInteger(1, decodeBase64(pArray));
713 }
714
715 /**
716 * Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
717 *
718 * @param bigInt
719 * a BigInteger
720 * @return A byte array containing base64 character data
721 * @throws NullPointerException
722 * if null is passed in
723 * @since 1.4
724 */
725 public static byte[] encodeInteger(final BigInteger bigInt) {
726 if (bigInt == null) {
727 throw new NullPointerException("encodeInteger called with null parameter");
728 }
729 return encodeBase64(toIntegerBytes(bigInt), false);
730 }
731
732 /**
733 * Returns a byte-array representation of a <code>BigInteger</code> without sign bit.
734 *
735 * @param bigInt
736 * <code>BigInteger</code> to be converted
737 * @return a byte array representation of the BigInteger parameter
738 */
739 static byte[] toIntegerBytes(final BigInteger bigInt) {
740 int bitlen = bigInt.bitLength();
741 // round bitlen
742 bitlen = ((bitlen + 7) >> 3) << 3;
743 final byte[] bigBytes = bigInt.toByteArray();
744
745 if (((bigInt.bitLength() % 8) != 0) && (((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) {
746 return bigBytes;
747 }
748 // set up params for copying everything but sign bit
749 int startSrc = 0;
750 int len = bigBytes.length;
751
752 // if bigInt is exactly byte-aligned, just skip signbit in copy
753 if ((bigInt.bitLength() % 8) == 0) {
754 startSrc = 1;
755 len--;
756 }
757 final int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
758 final byte[] resizedBytes = new byte[bitlen / 8];
759 System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
760 return resizedBytes;
761 }
762
763 /**
764 * Returns whether or not the <code>octet</code> is in the Base64 alphabet.
765 *
766 * @param octet
767 * The value to test
768 * @return {@code true} if the value is defined in the the Base64 alphabet {@code false} otherwise.
769 */
770 @Override
771 protected boolean isInAlphabet(final byte octet) {
772 return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1;
773 }
774
775 }