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; 019 020/** 021 * Provides Base32 encoding and decoding as defined by <a href="http://www.ietf.org/rfc/rfc4648.txt">RFC 4648</a>. 022 * 023 * <p> 024 * The class can be parameterized in the following manner with various constructors: 025 * </p> 026 * <ul> 027 * <li>Whether to use the "base32hex" variant instead of the default "base32"</li> 028 * <li>Line length: Default 76. Line length that aren't multiples of 8 will still essentially end up being multiples of 029 * 8 in the encoded data. 030 * <li>Line separator: Default is CRLF ("\r\n")</li> 031 * </ul> 032 * <p> 033 * This class operates directly on byte streams, and not character streams. 034 * </p> 035 * <p> 036 * This class is thread-safe. 037 * </p> 038 * 039 * @see <a href="http://www.ietf.org/rfc/rfc4648.txt">RFC 4648</a> 040 * 041 * @since 1.5 042 */ 043public class Base32 extends BaseNCodec { 044 045 /** 046 * BASE32 characters are 5 bits in length. 047 * They are formed by taking a block of five octets to form a 40-bit string, 048 * which is converted into eight BASE32 characters. 049 */ 050 private static final int BITS_PER_ENCODED_BYTE = 5; 051 private static final int BYTES_PER_ENCODED_BLOCK = 8; 052 private static final int BYTES_PER_UNENCODED_BLOCK = 5; 053 054 /** 055 * Chunk separator per RFC 2045 section 2.1. 056 * 057 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a> 058 */ 059 private static final byte[] CHUNK_SEPARATOR = {'\r', '\n'}; 060 061 /** 062 * This array is a lookup table that translates Unicode characters drawn from the "Base32 Alphabet" (as specified 063 * in Table 3 of RFC 4648) into their 5-bit positive integer equivalents. Characters that are not in the Base32 064 * alphabet but fall within the bounds of the array are translated to -1. 065 */ 066 private static final byte[] DECODE_TABLE = { 067 // 0 1 2 3 4 5 6 7 8 9 A B C D E F 068 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f 069 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f 070 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20-2f 071 -1, -1, 26, 27, 28, 29, 30, 31, -1, -1, -1, -1, -1, -1, -1, -1, // 30-3f 2-7 072 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 40-4f A-O 073 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // 50-5a P-Z 074 -1, -1, -1, -1, -1, // 5b - 5f 075 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 60 - 6f a-o 076 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // 70 - 7a p-z/**/ 077 }; 078 079 /** 080 * This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Alphabet" 081 * equivalents as specified in Table 3 of RFC 4648. 082 */ 083 private static final byte[] ENCODE_TABLE = { 084 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 085 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 086 '2', '3', '4', '5', '6', '7', 087 }; 088 089 /** 090 * This array is a lookup table that translates Unicode characters drawn from the "Base32 Hex Alphabet" (as 091 * specified in Table 4 of RFC 4648) into their 5-bit positive integer equivalents. Characters that are not in the 092 * Base32 Hex alphabet but fall within the bounds of the array are translated to -1. 093 */ 094 private static final byte[] HEX_DECODE_TABLE = { 095 // 0 1 2 3 4 5 6 7 8 9 A B C D E F 096 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f 097 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f 098 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20-2f 099 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, // 30-3f 2-7 100 -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 40-4f A-O 101 25, 26, 27, 28, 29, 30, 31, // 50-56 P-V 102 -1, -1, -1, -1, -1, -1, -1, -1, -1, // 57-5f Z-_ 103 -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 60-6f `-o 104 25, 26, 27, 28, 29, 30, 31 // 70-76 p-v 105 }; 106 107 /** 108 * This array is a lookup table that translates 5-bit positive integer index values into their 109 * "Base32 Hex Alphabet" equivalents as specified in Table 4 of RFC 4648. 110 */ 111 private static final byte[] HEX_ENCODE_TABLE = { 112 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 113 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 114 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 115 }; 116 117 /** Mask used to extract 5 bits, used when encoding Base32 bytes */ 118 private static final int MASK_5BITS = 0x1f; 119 120 // The static final fields above are used for the original static byte[] methods on Base32. 121 // The private member fields below are used with the new streaming approach, which requires 122 // some state be preserved between calls of encode() and decode(). 123 124 /** 125 * Place holder for the bytes we're dealing with for our based logic. 126 * Bitwise operations store and extract the encoding or decoding from this variable. 127 */ 128 129 /** 130 * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. 131 * <code>decodeSize = {@link #BYTES_PER_ENCODED_BLOCK} - 1 + lineSeparator.length;</code> 132 */ 133 private final int decodeSize; 134 135 /** 136 * Decode table to use. 137 */ 138 private final byte[] decodeTable; 139 140 /** 141 * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. 142 * <code>encodeSize = {@link #BYTES_PER_ENCODED_BLOCK} + lineSeparator.length;</code> 143 */ 144 private final int encodeSize; 145 146 /** 147 * Encode table to use. 148 */ 149 private final byte[] encodeTable; 150 151 /** 152 * Line separator for encoding. Not used when decoding. Only used if lineLength > 0. 153 */ 154 private final byte[] lineSeparator; 155 156 /** 157 * Creates a Base32 codec used for decoding and encoding. 158 * <p> 159 * When encoding the line length is 0 (no chunking). 160 * </p> 161 * 162 */ 163 public Base32() { 164 this(false); 165 } 166 167 /** 168 * Creates a Base32 codec used for decoding and encoding. 169 * <p> 170 * When encoding the line length is 0 (no chunking). 171 * </p> 172 * @param pad byte used as padding byte. 173 */ 174 public Base32(final byte pad) { 175 this(false, pad); 176 } 177 178 /** 179 * Creates a Base32 codec used for decoding and encoding. 180 * <p> 181 * When encoding the line length is 0 (no chunking). 182 * </p> 183 * @param useHex if {@code true} then use Base32 Hex alphabet 184 */ 185 public Base32(final boolean useHex) { 186 this(0, null, useHex, PAD_DEFAULT); 187 } 188 189 /** 190 * Creates a Base32 codec used for decoding and encoding. 191 * <p> 192 * When encoding the line length is 0 (no chunking). 193 * </p> 194 * @param useHex if {@code true} then use Base32 Hex alphabet 195 * @param pad byte used as padding byte. 196 */ 197 public Base32(final boolean useHex, final byte pad) { 198 this(0, null, useHex, pad); 199 } 200 201 /** 202 * Creates a Base32 codec used for decoding and encoding. 203 * <p> 204 * When encoding the line length is given in the constructor, the line separator is CRLF. 205 * </p> 206 * 207 * @param lineLength 208 * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 209 * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when 210 * decoding. 211 */ 212 public Base32(final int lineLength) { 213 this(lineLength, CHUNK_SEPARATOR); 214 } 215 216 /** 217 * Creates a Base32 codec used for decoding and encoding. 218 * <p> 219 * When encoding the line length and line separator are given in the constructor. 220 * </p> 221 * <p> 222 * Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data. 223 * </p> 224 * 225 * @param lineLength 226 * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 227 * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when 228 * decoding. 229 * @param lineSeparator 230 * Each line of encoded data will end with this sequence of bytes. 231 * @throws IllegalArgumentException 232 * The provided lineSeparator included some Base32 characters. That's not going to work! 233 */ 234 public Base32(final int lineLength, final byte[] lineSeparator) { 235 this(lineLength, lineSeparator, false, PAD_DEFAULT); 236 } 237 238 /** 239 * Creates a Base32 / Base32 Hex codec used for decoding and encoding. 240 * <p> 241 * When encoding the line length and line separator are given in the constructor. 242 * </p> 243 * <p> 244 * Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data. 245 * </p> 246 * 247 * @param lineLength 248 * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 249 * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when 250 * decoding. 251 * @param lineSeparator 252 * Each line of encoded data will end with this sequence of bytes. 253 * @param useHex 254 * if {@code true}, then use Base32 Hex alphabet, otherwise use Base32 alphabet 255 * @throws IllegalArgumentException 256 * The provided lineSeparator included some Base32 characters. That's not going to work! Or the 257 * lineLength > 0 and lineSeparator is null. 258 */ 259 public Base32(final int lineLength, final byte[] lineSeparator, final boolean useHex) { 260 this(lineLength, lineSeparator, useHex, PAD_DEFAULT); 261 } 262 263 /** 264 * Creates a Base32 / Base32 Hex codec used for decoding and encoding. 265 * <p> 266 * When encoding the line length and line separator are given in the constructor. 267 * </p> 268 * <p> 269 * Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data. 270 * </p> 271 * 272 * @param lineLength 273 * Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 274 * 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when 275 * decoding. 276 * @param lineSeparator 277 * Each line of encoded data will end with this sequence of bytes. 278 * @param useHex 279 * if {@code true}, then use Base32 Hex alphabet, otherwise use Base32 alphabet 280 * @param pad byte used as padding byte. 281 * @throws IllegalArgumentException 282 * The provided lineSeparator included some Base32 characters. That's not going to work! Or the 283 * lineLength > 0 and lineSeparator is null. 284 */ 285 public Base32(final int lineLength, final byte[] lineSeparator, final boolean useHex, final byte pad) { 286 super(BYTES_PER_UNENCODED_BLOCK, BYTES_PER_ENCODED_BLOCK, lineLength, 287 lineSeparator == null ? 0 : lineSeparator.length, pad); 288 if (useHex) { 289 this.encodeTable = HEX_ENCODE_TABLE; 290 this.decodeTable = HEX_DECODE_TABLE; 291 } else { 292 this.encodeTable = ENCODE_TABLE; 293 this.decodeTable = DECODE_TABLE; 294 } 295 if (lineLength > 0) { 296 if (lineSeparator == null) { 297 throw new IllegalArgumentException("lineLength " + lineLength + " > 0, but lineSeparator is null"); 298 } 299 // Must be done after initializing the tables 300 if (containsAlphabetOrPad(lineSeparator)) { 301 final String sep = StringUtils.newStringUtf8(lineSeparator); 302 throw new IllegalArgumentException("lineSeparator must not contain Base32 characters: [" + sep + "]"); 303 } 304 this.encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length; 305 this.lineSeparator = new byte[lineSeparator.length]; 306 System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length); 307 } else { 308 this.encodeSize = BYTES_PER_ENCODED_BLOCK; 309 this.lineSeparator = null; 310 } 311 this.decodeSize = this.encodeSize - 1; 312 313 if (isInAlphabet(pad) || isWhiteSpace(pad)) { 314 throw new IllegalArgumentException("pad must not be in alphabet or whitespace"); 315 } 316 } 317 318 /** 319 * <p> 320 * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once 321 * with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1" 322 * call is not necessary when decoding, but it doesn't hurt, either. 323 * </p> 324 * <p> 325 * Ignores all non-Base32 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are 326 * silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in, 327 * garbage-out philosophy: it will not check the provided data for validity. 328 * </p> 329 * 330 * @param in 331 * byte[] array of ascii data to Base32 decode. 332 * @param inPos 333 * Position to start reading data from. 334 * @param inAvail 335 * Amount of bytes available from input for decoding. 336 * @param context the context to be used 337 * 338 * Output is written to {@link Context#buffer} as 8-bit octets, using {@link Context#pos} as the buffer position 339 */ 340 @Override 341 void decode(final byte[] in, int inPos, final int inAvail, final Context context) { 342 // package protected for access from I/O streams 343 344 if (context.eof) { 345 return; 346 } 347 if (inAvail < 0) { 348 context.eof = true; 349 } 350 for (int i = 0; i < inAvail; i++) { 351 final byte b = in[inPos++]; 352 if (b == pad) { 353 // We're done. 354 context.eof = true; 355 break; 356 } 357 final byte[] buffer = ensureBufferSize(decodeSize, context); 358 if (b >= 0 && b < this.decodeTable.length) { 359 final int result = this.decodeTable[b]; 360 if (result >= 0) { 361 context.modulus = (context.modulus+1) % BYTES_PER_ENCODED_BLOCK; 362 // collect decoded bytes 363 context.lbitWorkArea = (context.lbitWorkArea << BITS_PER_ENCODED_BYTE) + result; 364 if (context.modulus == 0) { // we can output the 5 bytes 365 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 32) & MASK_8BITS); 366 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 24) & MASK_8BITS); 367 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS); 368 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); 369 buffer[context.pos++] = (byte) (context.lbitWorkArea & MASK_8BITS); 370 } 371 } 372 } 373 } 374 375 // Two forms of EOF as far as Base32 decoder is concerned: actual 376 // EOF (-1) and first time '=' character is encountered in stream. 377 // This approach makes the '=' padding characters completely optional. 378 if (context.eof && context.modulus >= 2) { // if modulus < 2, nothing to do 379 final byte[] buffer = ensureBufferSize(decodeSize, context); 380 381 // we ignore partial bytes, i.e. only multiples of 8 count 382 switch (context.modulus) { 383 case 2 : // 10 bits, drop 2 and output one byte 384 validateCharacter(2, context); 385 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 2) & MASK_8BITS); 386 break; 387 case 3 : // 15 bits, drop 7 and output 1 byte 388 validateCharacter(7, context); 389 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 7) & MASK_8BITS); 390 break; 391 case 4 : // 20 bits = 2*8 + 4 392 validateCharacter(4, context); 393 context.lbitWorkArea = context.lbitWorkArea >> 4; // drop 4 bits 394 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); 395 buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS); 396 break; 397 case 5 : // 25bits = 3*8 + 1 398 validateCharacter(1, context); 399 context.lbitWorkArea = context.lbitWorkArea >> 1; 400 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS); 401 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); 402 buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS); 403 break; 404 case 6 : // 30bits = 3*8 + 6 405 validateCharacter(6, context); 406 context.lbitWorkArea = context.lbitWorkArea >> 6; 407 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS); 408 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); 409 buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS); 410 break; 411 case 7 : // 35 = 4*8 +3 412 validateCharacter(3, context); 413 context.lbitWorkArea = context.lbitWorkArea >> 3; 414 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 24) & MASK_8BITS); 415 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS); 416 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS); 417 buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS); 418 break; 419 default: 420 // modulus can be 0-7, and we excluded 0,1 already 421 throw new IllegalStateException("Impossible modulus "+context.modulus); 422 } 423 } 424 } 425 426 /** 427 * <p> 428 * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with 429 * the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, so flush last 430 * remaining bytes (if not multiple of 5). 431 * </p> 432 * 433 * @param in 434 * byte[] array of binary data to Base32 encode. 435 * @param inPos 436 * Position to start reading data from. 437 * @param inAvail 438 * Amount of bytes available from input for encoding. 439 * @param context the context to be used 440 */ 441 @Override 442 void encode(final byte[] in, int inPos, final int inAvail, final Context context) { 443 // package protected for access from I/O streams 444 445 if (context.eof) { 446 return; 447 } 448 // inAvail < 0 is how we're informed of EOF in the underlying data we're 449 // encoding. 450 if (inAvail < 0) { 451 context.eof = true; 452 if (0 == context.modulus && lineLength == 0) { 453 return; // no leftovers to process and not using chunking 454 } 455 final byte[] buffer = ensureBufferSize(encodeSize, context); 456 final int savedPos = context.pos; 457 switch (context.modulus) { // % 5 458 case 0 : 459 break; 460 case 1 : // Only 1 octet; take top 5 bits then remainder 461 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 3) & MASK_5BITS]; // 8-1*5 = 3 462 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea << 2) & MASK_5BITS]; // 5-3=2 463 buffer[context.pos++] = pad; 464 buffer[context.pos++] = pad; 465 buffer[context.pos++] = pad; 466 buffer[context.pos++] = pad; 467 buffer[context.pos++] = pad; 468 buffer[context.pos++] = pad; 469 break; 470 case 2 : // 2 octets = 16 bits to use 471 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 11) & MASK_5BITS]; // 16-1*5 = 11 472 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 6) & MASK_5BITS]; // 16-2*5 = 6 473 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 1) & MASK_5BITS]; // 16-3*5 = 1 474 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea << 4) & MASK_5BITS]; // 5-1 = 4 475 buffer[context.pos++] = pad; 476 buffer[context.pos++] = pad; 477 buffer[context.pos++] = pad; 478 buffer[context.pos++] = pad; 479 break; 480 case 3 : // 3 octets = 24 bits to use 481 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 19) & MASK_5BITS]; // 24-1*5 = 19 482 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 14) & MASK_5BITS]; // 24-2*5 = 14 483 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 9) & MASK_5BITS]; // 24-3*5 = 9 484 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 4) & MASK_5BITS]; // 24-4*5 = 4 485 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea << 1) & MASK_5BITS]; // 5-4 = 1 486 buffer[context.pos++] = pad; 487 buffer[context.pos++] = pad; 488 buffer[context.pos++] = pad; 489 break; 490 case 4 : // 4 octets = 32 bits to use 491 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 27) & MASK_5BITS]; // 32-1*5 = 27 492 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 22) & MASK_5BITS]; // 32-2*5 = 22 493 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 17) & MASK_5BITS]; // 32-3*5 = 17 494 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 12) & MASK_5BITS]; // 32-4*5 = 12 495 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 7) & MASK_5BITS]; // 32-5*5 = 7 496 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 2) & MASK_5BITS]; // 32-6*5 = 2 497 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea << 3) & MASK_5BITS]; // 5-2 = 3 498 buffer[context.pos++] = pad; 499 break; 500 default: 501 throw new IllegalStateException("Impossible modulus "+context.modulus); 502 } 503 context.currentLinePos += context.pos - savedPos; // keep track of current line position 504 // if currentPos == 0 we are at the start of a line, so don't add CRLF 505 if (lineLength > 0 && context.currentLinePos > 0){ // add chunk separator if required 506 System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length); 507 context.pos += lineSeparator.length; 508 } 509 } else { 510 for (int i = 0; i < inAvail; i++) { 511 final byte[] buffer = ensureBufferSize(encodeSize, context); 512 context.modulus = (context.modulus+1) % BYTES_PER_UNENCODED_BLOCK; 513 int b = in[inPos++]; 514 if (b < 0) { 515 b += 256; 516 } 517 context.lbitWorkArea = (context.lbitWorkArea << 8) + b; // BITS_PER_BYTE 518 if (0 == context.modulus) { // we have enough bytes to create our output 519 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 35) & MASK_5BITS]; 520 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 30) & MASK_5BITS]; 521 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 25) & MASK_5BITS]; 522 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 20) & MASK_5BITS]; 523 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 15) & MASK_5BITS]; 524 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 10) & MASK_5BITS]; 525 buffer[context.pos++] = encodeTable[(int)(context.lbitWorkArea >> 5) & MASK_5BITS]; 526 buffer[context.pos++] = encodeTable[(int)context.lbitWorkArea & MASK_5BITS]; 527 context.currentLinePos += BYTES_PER_ENCODED_BLOCK; 528 if (lineLength > 0 && lineLength <= context.currentLinePos) { 529 System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length); 530 context.pos += lineSeparator.length; 531 context.currentLinePos = 0; 532 } 533 } 534 } 535 } 536 } 537 538 /** 539 * Returns whether or not the {@code octet} is in the Base32 alphabet. 540 * 541 * @param octet 542 * The value to test 543 * @return {@code true} if the value is defined in the the Base32 alphabet {@code false} otherwise. 544 */ 545 @Override 546 public boolean isInAlphabet(final byte octet) { 547 return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1; 548 } 549 550 /** 551 * <p> 552 * Validates whether the character is possible in the context of the set of possible base 32 values. 553 * </p> 554 * 555 * @param numBits number of least significant bits to check 556 * @param context the context to be used 557 * 558 * @throws IllegalArgumentException if the bits being checked contain any non-zero value 559 */ 560 private void validateCharacter(final int numBits, final Context context) { 561 if ((context.lbitWorkArea & numBits) != 0) { 562 throw new IllegalArgumentException( 563 "Last encoded character (before the paddings if any) is a valid base 32 alphabet but not a possible value"); 564 } 565 } 566}