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 018package org.apache.commons.codec.binary; 019 020import java.math.BigInteger; 021import java.util.Objects; 022 023import org.apache.commons.codec.CodecPolicy; 024 025/** 026 * Provides Base64 encoding and decoding as defined by <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>. 027 * 028 * <p> 029 * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose 030 * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein. 031 * </p> 032 * <p> 033 * The class can be parameterized in the following manner with various constructors: 034 * </p> 035 * <ul> 036 * <li>URL-safe mode: Default off.</li> 037 * <li>Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of 038 * 4 in the encoded data. 039 * <li>Line separator: Default is CRLF ("\r\n")</li> 040 * </ul> 041 * <p> 042 * The URL-safe parameter is only applied to encode operations. Decoding seamlessly handles both modes. 043 * </p> 044 * <p> 045 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only 046 * encode/decode character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, 047 * UTF-8, etc). 048 * </p> 049 * <p> 050 * This class is thread-safe. 051 * </p> 052 * 053 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a> 054 * @since 1.0 055 */ 056public class Base64 extends BaseNCodec { 057 058 /** 059 * BASE64 characters are 6 bits in length. 060 * They are formed by taking a block of 3 octets to form a 24-bit string, 061 * which is converted into 4 BASE64 characters. 062 */ 063 private static final int BITS_PER_ENCODED_BYTE = 6; 064 private static final int BYTES_PER_UNENCODED_BLOCK = 3; 065 private static final int BYTES_PER_ENCODED_BLOCK = 4; 066 067 /** 068 * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet" 069 * equivalents as specified in Table 1 of RFC 2045. 070 * <p> 071 * Thanks to "commons" project in ws.apache.org for this code. 072 * https://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ 073 * </p> 074 */ 075 private static final byte[] STANDARD_ENCODE_TABLE = { 076 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 077 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 078 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 079 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 080 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' 081 }; 082 083 /** 084 * This is a copy of the STANDARD_ENCODE_TABLE above, but with + and / 085 * changed to - and _ to make the encoded Base64 results more URL-SAFE. 086 * This table is only used when the Base64's mode is set to URL-SAFE. 087 */ 088 private static final byte[] URL_SAFE_ENCODE_TABLE = { 089 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 090 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 091 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 092 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 093 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_' 094 }; 095 096 /** 097 * This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified 098 * in Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64 099 * alphabet but fall within the bounds of the array are translated to -1. 100 * <p> 101 * Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both 102 * URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit). 103 * </p> 104 * <p> 105 * Thanks to "commons" project in ws.apache.org for this code. 106 * https://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ 107 * </p> 108 */ 109 private static final byte[] DECODE_TABLE = { 110 // 0 1 2 3 4 5 6 7 8 9 A B C D E F 111 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f 112 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f 113 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, // 20-2f + - / 114 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, // 30-3f 0-9 115 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 40-4f A-O 116 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, // 50-5f P-Z _ 117 -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, // 60-6f a-o 118 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 // 70-7a p-z 119 }; 120 121 // The static final fields above are used for the original static byte[] methods on Base64. 122 // The private member fields below are used with the new streaming approach, which requires 123 // some state be preserved between calls of encode() and decode(). 124 125 /** 126 * Base64 uses 6-bit fields. 127 */ 128 /** Mask used to extract 6 bits, used when encoding */ 129 private static final int MASK_6BITS = 0x3f; 130 /** Mask used to extract 4 bits, used when decoding final trailing character. */ 131 private static final int MASK_4BITS = 0xf; 132 /** Mask used to extract 2 bits, used when decoding final trailing character. */ 133 private static final int MASK_2BITS = 0x3; 134 135 /** 136 * Decodes Base64 data into octets. 137 * <p> 138 * <b>Note:</b> this method seamlessly handles data encoded in URL-safe or normal mode. 139 * </p> 140 * 141 * @param base64Data 142 * Byte array containing Base64 data 143 * @return Array containing decoded data. 144 */ 145 public static byte[] decodeBase64(final byte[] base64Data) { 146 return new Base64().decode(base64Data); 147 } 148 149 /** 150 * Decodes a Base64 String into octets. 151 * <p> 152 * <b>Note:</b> this method seamlessly handles data encoded in URL-safe or normal mode. 153 * </p> 154 * 155 * @param base64String 156 * String containing Base64 data 157 * @return Array containing decoded data. 158 * @since 1.4 159 */ 160 public static byte[] decodeBase64(final String base64String) { 161 return new Base64().decode(base64String); 162 } 163 164 // Implementation of integer encoding used for crypto 165 /** 166 * Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature. 167 * 168 * @param pArray 169 * a byte array containing base64 character data 170 * @return A BigInteger 171 * @since 1.4 172 */ 173 public static BigInteger decodeInteger(final byte[] pArray) { 174 return new BigInteger(1, decodeBase64(pArray)); 175 } 176 177 /** 178 * Encodes binary data using the base64 algorithm but does not chunk the output. 179 * 180 * @param binaryData 181 * binary data to encode 182 * @return byte[] containing Base64 characters in their UTF-8 representation. 183 */ 184 public static byte[] encodeBase64(final byte[] binaryData) { 185 return encodeBase64(binaryData, false); 186 } 187 188 /** 189 * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks. 190 * 191 * @param binaryData 192 * Array containing binary data to encode. 193 * @param isChunked 194 * if {@code true} this encoder will chunk the base64 output into 76 character blocks 195 * @return Base64-encoded data. 196 * @throws IllegalArgumentException 197 * Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE} 198 */ 199 public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked) { 200 return encodeBase64(binaryData, isChunked, false); 201 } 202 203 /** 204 * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks. 205 * 206 * @param binaryData 207 * Array containing binary data to encode. 208 * @param isChunked 209 * if {@code true} this encoder will chunk the base64 output into 76 character blocks 210 * @param urlSafe 211 * if {@code true} this encoder will emit - and _ instead of the usual + and / characters. 212 * <b>Note: no padding is added when encoding using the URL-safe alphabet.</b> 213 * @return Base64-encoded data. 214 * @throws IllegalArgumentException 215 * Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE} 216 * @since 1.4 217 */ 218 public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe) { 219 return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE); 220 } 221 222 /** 223 * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks. 224 * 225 * @param binaryData 226 * Array containing binary data to encode. 227 * @param isChunked 228 * if {@code true} this encoder will chunk the base64 output into 76 character blocks 229 * @param urlSafe 230 * if {@code true} this encoder will emit - and _ instead of the usual + and / characters. 231 * <b>Note: no padding is added when encoding using the URL-safe alphabet.</b> 232 * @param maxResultSize 233 * The maximum result size to accept. 234 * @return Base64-encoded data. 235 * @throws IllegalArgumentException 236 * Thrown when the input array needs an output array bigger than maxResultSize 237 * @since 1.4 238 */ 239 public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, 240 final boolean urlSafe, final int maxResultSize) { 241 if (BinaryCodec.isEmpty(binaryData)) { 242 return binaryData; 243 } 244 245 // Create this so can use the super-class method 246 // Also ensures that the same roundings are performed by the ctor and the code 247 final Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe); 248 final long len = b64.getEncodedLength(binaryData); 249 if (len > maxResultSize) { 250 throw new IllegalArgumentException("Input array too big, the output array would be bigger (" + 251 len + 252 ") than the specified maximum size of " + 253 maxResultSize); 254 } 255 256 return b64.encode(binaryData); 257 } 258 259 /** 260 * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks 261 * 262 * @param binaryData 263 * binary data to encode 264 * @return Base64 characters chunked in 76 character blocks 265 */ 266 public static byte[] encodeBase64Chunked(final byte[] binaryData) { 267 return encodeBase64(binaryData, true); 268 } 269 270 /** 271 * Encodes binary data using the base64 algorithm but does not chunk the output. 272 * 273 * NOTE: We changed the behavior of this method from multi-line chunking (commons-codec-1.4) to 274 * single-line non-chunking (commons-codec-1.5). 275 * 276 * @param binaryData 277 * binary data to encode 278 * @return String containing Base64 characters. 279 * @since 1.4 (NOTE: 1.4 chunked the output, whereas 1.5 does not). 280 */ 281 public static String encodeBase64String(final byte[] binaryData) { 282 return StringUtils.newStringUsAscii(encodeBase64(binaryData, false)); 283 } 284 285 /** 286 * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The 287 * url-safe variation emits - and _ instead of + and / characters. 288 * <b>Note: no padding is added.</b> 289 * @param binaryData 290 * binary data to encode 291 * @return byte[] containing Base64 characters in their UTF-8 representation. 292 * @since 1.4 293 */ 294 public static byte[] encodeBase64URLSafe(final byte[] binaryData) { 295 return encodeBase64(binaryData, false, true); 296 } 297 298 /** 299 * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The 300 * url-safe variation emits - and _ instead of + and / characters. 301 * <b>Note: no padding is added.</b> 302 * @param binaryData 303 * binary data to encode 304 * @return String containing Base64 characters 305 * @since 1.4 306 */ 307 public static String encodeBase64URLSafeString(final byte[] binaryData) { 308 return StringUtils.newStringUsAscii(encodeBase64(binaryData, false, true)); 309 } 310 311 /** 312 * Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature. 313 * 314 * @param bigInteger 315 * a BigInteger 316 * @return A byte array containing base64 character data 317 * @throws NullPointerException 318 * if null is passed in 319 * @since 1.4 320 */ 321 public static byte[] encodeInteger(final BigInteger bigInteger) { 322 Objects.requireNonNull(bigInteger, "bigInteger"); 323 return encodeBase64(toIntegerBytes(bigInteger), false); 324 } 325 326 /** 327 * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the 328 * method treats whitespace as valid. 329 * 330 * @param arrayOctet 331 * byte array to test 332 * @return {@code true} if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; 333 * {@code false}, otherwise 334 * @deprecated 1.5 Use {@link #isBase64(byte[])}, will be removed in 2.0. 335 */ 336 @Deprecated 337 public static boolean isArrayByteBase64(final byte[] arrayOctet) { 338 return isBase64(arrayOctet); 339 } 340 341 /** 342 * Returns whether or not the {@code octet} is in the base 64 alphabet. 343 * 344 * @param octet 345 * The value to test 346 * @return {@code true} if the value is defined in the base 64 alphabet, {@code false} otherwise. 347 * @since 1.4 348 */ 349 public static boolean isBase64(final byte octet) { 350 return octet == PAD_DEFAULT || octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1; 351 } 352 353 /** 354 * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the 355 * method treats whitespace as valid. 356 * 357 * @param arrayOctet 358 * byte array to test 359 * @return {@code true} if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; 360 * {@code false}, otherwise 361 * @since 1.5 362 */ 363 public static boolean isBase64(final byte[] arrayOctet) { 364 for (final byte element : arrayOctet) { 365 if (!isBase64(element) && !Character.isWhitespace(element)) { 366 return false; 367 } 368 } 369 return true; 370 } 371 372 /** 373 * Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the 374 * method treats whitespace as valid. 375 * 376 * @param base64 377 * String to test 378 * @return {@code true} if all characters in the String are valid characters in the Base64 alphabet or if 379 * the String is empty; {@code false}, otherwise 380 * @since 1.5 381 */ 382 public static boolean isBase64(final String base64) { 383 return isBase64(StringUtils.getBytesUtf8(base64)); 384 } 385 386 /** 387 * Returns a byte-array representation of a {@code BigInteger} without sign bit. 388 * 389 * @param bigInt 390 * {@code BigInteger} to be converted 391 * @return a byte array representation of the BigInteger parameter 392 */ 393 static byte[] toIntegerBytes(final BigInteger bigInt) { 394 int bitlen = bigInt.bitLength(); 395 // round bitlen 396 bitlen = bitlen + 7 >> 3 << 3; 397 final byte[] bigBytes = bigInt.toByteArray(); 398 399 if (bigInt.bitLength() % 8 != 0 && bigInt.bitLength() / 8 + 1 == bitlen / 8) { 400 return bigBytes; 401 } 402 // set up params for copying everything but sign bit 403 int startSrc = 0; 404 int len = bigBytes.length; 405 406 // if bigInt is exactly byte-aligned, just skip signbit in copy 407 if (bigInt.bitLength() % 8 == 0) { 408 startSrc = 1; 409 len--; 410 } 411 final int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec 412 final byte[] resizedBytes = new byte[bitlen / 8]; 413 System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len); 414 return resizedBytes; 415 } 416 417 /** 418 * Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able 419 * to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch 420 * between the two modes. 421 */ 422 private final byte[] encodeTable; 423 424 /** Only one decode table currently; keep for consistency with Base32 code. */ 425 private final byte[] decodeTable = DECODE_TABLE; 426 427 /** 428 * Line separator for encoding. Not used when decoding. Only used if lineLength > 0. 429 */ 430 private final byte[] lineSeparator; 431 432 /** 433 * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. 434 * {@code decodeSize = 3 + lineSeparator.length;} 435 */ 436 private final int decodeSize; 437 438 /** 439 * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. 440 * {@code encodeSize = 4 + lineSeparator.length;} 441 */ 442 private final int encodeSize; 443 444 /** 445 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode. 446 * <p> 447 * When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE. 448 * </p> 449 * 450 * <p> 451 * When decoding all variants are supported. 452 * </p> 453 */ 454 public Base64() { 455 this(0); 456 } 457 458 /** 459 * Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode. 460 * <p> 461 * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE. 462 * </p> 463 * 464 * <p> 465 * When decoding all variants are supported. 466 * </p> 467 * 468 * @param urlSafe 469 * if {@code true}, URL-safe encoding is used. In most cases this should be set to 470 * {@code false}. 471 * @since 1.4 472 */ 473 public Base64(final boolean urlSafe) { 474 this(MIME_CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe); 475 } 476 477 /** 478 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode. 479 * <p> 480 * When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is 481 * STANDARD_ENCODE_TABLE. 482 * </p> 483 * <p> 484 * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data. 485 * </p> 486 * <p> 487 * When decoding all variants are supported. 488 * </p> 489 * 490 * @param lineLength 491 * Each line of encoded data will be at most of the given length (rounded down to the nearest multiple of 492 * 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when 493 * decoding. 494 * @since 1.4 495 */ 496 public Base64(final int lineLength) { 497 this(lineLength, CHUNK_SEPARATOR); 498 } 499 500 /** 501 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode. 502 * <p> 503 * When encoding the line length and line separator are given in the constructor, and the encoding table is 504 * STANDARD_ENCODE_TABLE. 505 * </p> 506 * <p> 507 * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data. 508 * </p> 509 * <p> 510 * When decoding all variants are supported. 511 * </p> 512 * 513 * @param lineLength 514 * Each line of encoded data will be at most of the given length (rounded down to the nearest multiple of 515 * 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when 516 * decoding. 517 * @param lineSeparator 518 * Each line of encoded data will end with this sequence of bytes. 519 * @throws IllegalArgumentException 520 * Thrown when the provided lineSeparator included some base64 characters. 521 * @since 1.4 522 */ 523 public Base64(final int lineLength, final byte[] lineSeparator) { 524 this(lineLength, lineSeparator, false); 525 } 526 527 /** 528 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode. 529 * <p> 530 * When encoding the line length and line separator are given in the constructor, and the encoding table is 531 * STANDARD_ENCODE_TABLE. 532 * </p> 533 * <p> 534 * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data. 535 * </p> 536 * <p> 537 * When decoding all variants are supported. 538 * </p> 539 * 540 * @param lineLength 541 * Each line of encoded data will be at most of the given length (rounded down to the nearest multiple of 542 * 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when 543 * decoding. 544 * @param lineSeparator 545 * Each line of encoded data will end with this sequence of bytes. 546 * @param urlSafe 547 * Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode 548 * operations. Decoding seamlessly handles both modes. 549 * <b>Note: no padding is added when using the URL-safe alphabet.</b> 550 * @throws IllegalArgumentException 551 * Thrown when the {@code lineSeparator} contains Base64 characters. 552 * @since 1.4 553 */ 554 public Base64(final int lineLength, final byte[] lineSeparator, final boolean urlSafe) { 555 this(lineLength, lineSeparator, urlSafe, DECODING_POLICY_DEFAULT); 556 } 557 558 /** 559 * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode. 560 * <p> 561 * When encoding the line length and line separator are given in the constructor, and the encoding table is 562 * STANDARD_ENCODE_TABLE. 563 * </p> 564 * <p> 565 * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data. 566 * </p> 567 * <p> 568 * When decoding all variants are supported. 569 * </p> 570 * 571 * @param lineLength 572 * Each line of encoded data will be at most of the given length (rounded down to the nearest multiple of 573 * 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when 574 * decoding. 575 * @param lineSeparator 576 * Each line of encoded data will end with this sequence of bytes. 577 * @param urlSafe 578 * Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode 579 * operations. Decoding seamlessly handles both modes. 580 * <b>Note: no padding is added when using the URL-safe alphabet.</b> 581 * @param decodingPolicy The decoding policy. 582 * @throws IllegalArgumentException 583 * Thrown when the {@code lineSeparator} contains Base64 characters. 584 * @since 1.15 585 */ 586 public Base64(final int lineLength, final byte[] lineSeparator, final boolean urlSafe, 587 final CodecPolicy decodingPolicy) { 588 super(BYTES_PER_UNENCODED_BLOCK, BYTES_PER_ENCODED_BLOCK, 589 lineLength, 590 lineSeparator == null ? 0 : lineSeparator.length, 591 PAD_DEFAULT, 592 decodingPolicy); 593 // TODO could be simplified if there is no requirement to reject invalid line sep when length <=0 594 // @see test case Base64Test.testConstructors() 595 if (lineSeparator != null) { 596 if (containsAlphabetOrPad(lineSeparator)) { 597 final String sep = StringUtils.newStringUtf8(lineSeparator); 598 throw new IllegalArgumentException("lineSeparator must not contain base64 characters: [" + sep + "]"); 599 } 600 if (lineLength > 0){ // null line-sep forces no chunking rather than throwing IAE 601 this.encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length; 602 this.lineSeparator = lineSeparator.clone(); 603 } else { 604 this.encodeSize = BYTES_PER_ENCODED_BLOCK; 605 this.lineSeparator = null; 606 } 607 } else { 608 this.encodeSize = BYTES_PER_ENCODED_BLOCK; 609 this.lineSeparator = null; 610 } 611 this.decodeSize = this.encodeSize - 1; 612 this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE; 613 } 614 615 // Implementation of the Encoder Interface 616 617 /** 618 * <p> 619 * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once 620 * with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1" 621 * call is not necessary when decoding, but it doesn't hurt, either. 622 * </p> 623 * <p> 624 * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are 625 * silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in, 626 * garbage-out philosophy: it will not check the provided data for validity. 627 * </p> 628 * <p> 629 * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach. 630 * https://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ 631 * </p> 632 * 633 * @param input 634 * byte[] array of ASCII data to base64 decode. 635 * @param inPos 636 * Position to start reading data from. 637 * @param inAvail 638 * Amount of bytes available from input for decoding. 639 * @param context 640 * the context to be used 641 */ 642 @Override 643 void decode(final byte[] input, int inPos, final int inAvail, final Context context) { 644 if (context.eof) { 645 return; 646 } 647 if (inAvail < 0) { 648 context.eof = true; 649 } 650 for (int i = 0; i < inAvail; i++) { 651 final byte[] buffer = ensureBufferSize(decodeSize, context); 652 final byte b = input[inPos++]; 653 if (b == pad) { 654 // We're done. 655 context.eof = true; 656 break; 657 } 658 if (b >= 0 && b < DECODE_TABLE.length) { 659 final int result = DECODE_TABLE[b]; 660 if (result >= 0) { 661 context.modulus = (context.modulus+1) % BYTES_PER_ENCODED_BLOCK; 662 context.ibitWorkArea = (context.ibitWorkArea << BITS_PER_ENCODED_BYTE) + result; 663 if (context.modulus == 0) { 664 buffer[context.pos++] = (byte) (context.ibitWorkArea >> 16 & MASK_8BITS); 665 buffer[context.pos++] = (byte) (context.ibitWorkArea >> 8 & MASK_8BITS); 666 buffer[context.pos++] = (byte) (context.ibitWorkArea & MASK_8BITS); 667 } 668 } 669 } 670 } 671 672 // Two forms of EOF as far as base64 decoder is concerned: actual 673 // EOF (-1) and first time '=' character is encountered in stream. 674 // This approach makes the '=' padding characters completely optional. 675 if (context.eof && context.modulus != 0) { 676 final byte[] buffer = ensureBufferSize(decodeSize, context); 677 678 // We have some spare bits remaining 679 // Output all whole multiples of 8 bits and ignore the rest 680 switch (context.modulus) { 681// case 0 : // impossible, as excluded above 682 case 1 : // 6 bits - either ignore entirely, or raise an exception 683 validateTrailingCharacter(); 684 break; 685 case 2 : // 12 bits = 8 + 4 686 validateCharacter(MASK_4BITS, context); 687 context.ibitWorkArea = context.ibitWorkArea >> 4; // dump the extra 4 bits 688 buffer[context.pos++] = (byte) (context.ibitWorkArea & MASK_8BITS); 689 break; 690 case 3 : // 18 bits = 8 + 8 + 2 691 validateCharacter(MASK_2BITS, context); 692 context.ibitWorkArea = context.ibitWorkArea >> 2; // dump 2 bits 693 buffer[context.pos++] = (byte) (context.ibitWorkArea >> 8 & MASK_8BITS); 694 buffer[context.pos++] = (byte) (context.ibitWorkArea & MASK_8BITS); 695 break; 696 default: 697 throw new IllegalStateException("Impossible modulus " + context.modulus); 698 } 699 } 700 } 701 702 /** 703 * <p> 704 * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with 705 * the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, to flush last 706 * remaining bytes (if not multiple of 3). 707 * </p> 708 * <p><b>Note: no padding is added when encoding using the URL-safe alphabet.</b></p> 709 * <p> 710 * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach. 711 * https://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/ 712 * </p> 713 * 714 * @param in 715 * byte[] array of binary data to base64 encode. 716 * @param inPos 717 * Position to start reading data from. 718 * @param inAvail 719 * Amount of bytes available from input for encoding. 720 * @param context 721 * the context to be used 722 */ 723 @Override 724 void encode(final byte[] in, int inPos, final int inAvail, final Context context) { 725 if (context.eof) { 726 return; 727 } 728 // inAvail < 0 is how we're informed of EOF in the underlying data we're 729 // encoding. 730 if (inAvail < 0) { 731 context.eof = true; 732 if (0 == context.modulus && lineLength == 0) { 733 return; // no leftovers to process and not using chunking 734 } 735 final byte[] buffer = ensureBufferSize(encodeSize, context); 736 final int savedPos = context.pos; 737 switch (context.modulus) { // 0-2 738 case 0 : // nothing to do here 739 break; 740 case 1 : // 8 bits = 6 + 2 741 // top 6 bits: 742 buffer[context.pos++] = encodeTable[context.ibitWorkArea >> 2 & MASK_6BITS]; 743 // remaining 2: 744 buffer[context.pos++] = encodeTable[context.ibitWorkArea << 4 & MASK_6BITS]; 745 // URL-SAFE skips the padding to further reduce size. 746 if (encodeTable == STANDARD_ENCODE_TABLE) { 747 buffer[context.pos++] = pad; 748 buffer[context.pos++] = pad; 749 } 750 break; 751 752 case 2 : // 16 bits = 6 + 6 + 4 753 buffer[context.pos++] = encodeTable[context.ibitWorkArea >> 10 & MASK_6BITS]; 754 buffer[context.pos++] = encodeTable[context.ibitWorkArea >> 4 & MASK_6BITS]; 755 buffer[context.pos++] = encodeTable[context.ibitWorkArea << 2 & MASK_6BITS]; 756 // URL-SAFE skips the padding to further reduce size. 757 if (encodeTable == STANDARD_ENCODE_TABLE) { 758 buffer[context.pos++] = pad; 759 } 760 break; 761 default: 762 throw new IllegalStateException("Impossible modulus " + context.modulus); 763 } 764 context.currentLinePos += context.pos - savedPos; // keep track of current line position 765 // if currentPos == 0 we are at the start of a line, so don't add CRLF 766 if (lineLength > 0 && context.currentLinePos > 0) { 767 System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length); 768 context.pos += lineSeparator.length; 769 } 770 } else { 771 for (int i = 0; i < inAvail; i++) { 772 final byte[] buffer = ensureBufferSize(encodeSize, context); 773 context.modulus = (context.modulus+1) % BYTES_PER_UNENCODED_BLOCK; 774 int b = in[inPos++]; 775 if (b < 0) { 776 b += 256; 777 } 778 context.ibitWorkArea = (context.ibitWorkArea << 8) + b; // BITS_PER_BYTE 779 if (0 == context.modulus) { // 3 bytes = 24 bits = 4 * 6 bits to extract 780 buffer[context.pos++] = encodeTable[context.ibitWorkArea >> 18 & MASK_6BITS]; 781 buffer[context.pos++] = encodeTable[context.ibitWorkArea >> 12 & MASK_6BITS]; 782 buffer[context.pos++] = encodeTable[context.ibitWorkArea >> 6 & MASK_6BITS]; 783 buffer[context.pos++] = encodeTable[context.ibitWorkArea & MASK_6BITS]; 784 context.currentLinePos += BYTES_PER_ENCODED_BLOCK; 785 if (lineLength > 0 && lineLength <= context.currentLinePos) { 786 System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length); 787 context.pos += lineSeparator.length; 788 context.currentLinePos = 0; 789 } 790 } 791 } 792 } 793 } 794 795 /** 796 * Returns whether or not the {@code octet} is in the Base64 alphabet. 797 * 798 * @param octet 799 * The value to test 800 * @return {@code true} if the value is defined in the Base64 alphabet {@code false} otherwise. 801 */ 802 @Override 803 protected boolean isInAlphabet(final byte octet) { 804 return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1; 805 } 806 807 /** 808 * Returns our current encode mode. True if we're URL-SAFE, false otherwise. 809 * 810 * @return true if we're in URL-SAFE mode, false otherwise. 811 * @since 1.4 812 */ 813 public boolean isUrlSafe() { 814 return this.encodeTable == URL_SAFE_ENCODE_TABLE; 815 } 816 817 /** 818 * Validates whether decoding the final trailing character is possible in the context 819 * of the set of possible base 64 values. 820 * <p> 821 * The character is valid if the lower bits within the provided mask are zero. This 822 * is used to test the final trailing base-64 digit is zero in the bits that will be discarded. 823 * </p> 824 * 825 * @param emptyBitsMask The mask of the lower bits that should be empty 826 * @param context the context to be used 827 * 828 * @throws IllegalArgumentException if the bits being checked contain any non-zero value 829 */ 830 private void validateCharacter(final int emptyBitsMask, final Context context) { 831 if (isStrictDecoding() && (context.ibitWorkArea & emptyBitsMask) != 0) { 832 throw new IllegalArgumentException( 833 "Strict decoding: Last encoded character (before the paddings if any) is a valid " + 834 "base 64 alphabet but not a possible encoding. " + 835 "Expected the discarded bits from the character to be zero."); 836 } 837 } 838 839 /** 840 * Validates whether decoding allows an entire final trailing character that cannot be 841 * used for a complete byte. 842 * 843 * @throws IllegalArgumentException if strict decoding is enabled 844 */ 845 private void validateTrailingCharacter() { 846 if (isStrictDecoding()) { 847 throw new IllegalArgumentException( 848 "Strict decoding: Last encoded character (before the paddings if any) is a valid " + 849 "base 64 alphabet but not a possible encoding. " + 850 "Decoding requires at least two trailing 6-bit characters to create bytes."); 851 } 852 } 853 854}