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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.net.util;
19  
20  import java.io.UnsupportedEncodingException;
21  import java.math.BigInteger;
22  
23  
24  
25  /**
26   * Provides Base64 encoding and decoding as defined by RFC 2045.
27   *
28   * <p>
29   * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
30   * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
31   * </p>
32   * <p>
33   * The class can be parameterized in the following manner with various constructors:
34   * <ul>
35   * <li>URL-safe mode: Default off.</li>
36   * <li>Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of
37   * 4 in the encoded data.
38   * <li>Line separator: Default is CRLF ("\r\n")</li>
39   * </ul>
40   * </p>
41   * <p>
42   * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode
43   * character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
44   * </p>
45   *
46   * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
47   * @author Apache Software Foundation
48   * @since 2.2
49   * @version $Id: Base64.java 1489533 2013-06-04 17:49:00Z sebb $
50   */
51  public class Base64 {
52      private static final int DEFAULT_BUFFER_RESIZE_FACTOR = 2;
53  
54      private static final int DEFAULT_BUFFER_SIZE = 8192;
55  
56      /**
57       * Chunk size per RFC 2045 section 6.8.
58       *
59       * <p>
60       * The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
61       * equal signs.
62       * </p>
63       *
64       * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
65       */
66      static final int CHUNK_SIZE = 76;
67  
68      /**
69       * Chunk separator per RFC 2045 section 2.1.
70       *
71       * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
72       */
73      private static final byte[] CHUNK_SEPARATOR = {'\r', '\n'};
74  
75      private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
76  
77      /**
78       * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet"
79       * equivalents as specified in Table 1 of RFC 2045.
80       *
81       * Thanks to "commons" project in ws.apache.org for this code.
82       * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
83       */
84      private static final byte[] STANDARD_ENCODE_TABLE = {
85              'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
86              'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
87              'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
88              'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
89              '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
90      };
91  
92      /**
93       * This is a copy of the STANDARD_ENCODE_TABLE above, but with + and /
94       * changed to - and _ to make the encoded Base64 results more URL-SAFE.
95       * This table is only used when the Base64's mode is set to URL-SAFE.
96       */
97      private static final byte[] URL_SAFE_ENCODE_TABLE = {
98              'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
99              'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
100             'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
101             'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
102             '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'
103     };
104 
105     /**
106      * Byte used to pad output.
107      */
108     private static final byte PAD = '=';
109 
110     /**
111      * This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified in
112      * Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64
113      * alphabet but fall within the bounds of the array are translated to -1.
114      *
115      * Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both
116      * URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit).
117      *
118      * Thanks to "commons" project in ws.apache.org for this code.
119      * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
120      */
121     private static final byte[] DECODE_TABLE = {
122             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
123             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
124             -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, 52, 53, 54,
125             55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4,
126             5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
127             24, 25, -1, -1, -1, -1, 63, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34,
128             35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
129     };
130 
131     /** Mask used to extract 6 bits, used when encoding */
132     private static final int MASK_6BITS = 0x3f;
133 
134     /** Mask used to extract 8 bits, used in decoding base64 bytes */
135     private static final int MASK_8BITS = 0xff;
136 
137     // The static final fields above are used for the original static byte[] methods on Base64.
138     // The private member fields below are used with the new streaming approach, which requires
139     // some state be preserved between calls of encode() and decode().
140 
141     /**
142      * Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able
143      * to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch
144      * between the two modes.
145      */
146     private final byte[] encodeTable;
147 
148     /**
149      * Line length for encoding. Not used when decoding. A value of zero or less implies no chunking of the base64
150      * encoded data.
151      */
152     private final int lineLength;
153 
154     /**
155      * Line separator for encoding. Not used when decoding. Only used if lineLength > 0.
156      */
157     private final byte[] lineSeparator;
158 
159     /**
160      * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
161      * <code>decodeSize = 3 + lineSeparator.length;</code>
162      */
163     private final int decodeSize;
164 
165     /**
166      * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
167      * <code>encodeSize = 4 + lineSeparator.length;</code>
168      */
169     private final int encodeSize;
170 
171     /**
172      * Buffer for streaming.
173      */
174     private byte[] buffer;
175 
176     /**
177      * Position where next character should be written in the buffer.
178      */
179     private int pos;
180 
181     /**
182      * Position where next character should be read from the buffer.
183      */
184     private int readPos;
185 
186     /**
187      * Variable tracks how many characters have been written to the current line. Only used when encoding. We use it to
188      * make sure each encoded line never goes beyond lineLength (if lineLength > 0).
189      */
190     private int currentLinePos;
191 
192     /**
193      * Writes to the buffer only occur after every 3 reads when encoding, an every 4 reads when decoding. This variable
194      * helps track that.
195      */
196     private int modulus;
197 
198     /**
199      * Boolean flag to indicate the EOF has been reached. Once EOF has been reached, this Base64 object becomes useless,
200      * and must be thrown away.
201      */
202     private boolean eof;
203 
204     /**
205      * Place holder for the 3 bytes we're dealing with for our base64 logic. Bitwise operations store and extract the
206      * base64 encoding or decoding from this variable.
207      */
208     private int x;
209 
210     /**
211      * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
212      * <p>
213      * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
214      * </p>
215      *
216      * <p>
217      * When decoding all variants are supported.
218      * </p>
219      */
220     public Base64() {
221         this(false);
222     }
223 
224     /**
225      * Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
226      * <p>
227      * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
228      * </p>
229      *
230      * <p>
231      * When decoding all variants are supported.
232      * </p>
233      *
234      * @param urlSafe
235      *            if <code>true</code>, URL-safe encoding is used. In most cases this should be set to
236      *            <code>false</code>.
237      * @since 1.4
238      */
239     public Base64(boolean urlSafe) {
240         this(CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);
241     }
242 
243     /**
244      * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
245      * <p>
246      * When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is
247      * STANDARD_ENCODE_TABLE.
248      * </p>
249      * <p>
250      * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
251      * </p>
252      * <p>
253      * When decoding all variants are supported.
254      * </p>
255      *
256      * @param lineLength
257      *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
258      *            If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
259      * @since 1.4
260      */
261     public Base64(int lineLength) {
262         this(lineLength, CHUNK_SEPARATOR);
263     }
264 
265     /**
266      * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
267      * <p>
268      * When encoding the line length and line separator are given in the constructor, and the encoding table is
269      * STANDARD_ENCODE_TABLE.
270      * </p>
271      * <p>
272      * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
273      * </p>
274      * <p>
275      * When decoding all variants are supported.
276      * </p>
277      *
278      * @param lineLength
279      *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
280      *            If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
281      * @param lineSeparator
282      *            Each line of encoded data will end with this sequence of bytes.
283      * @throws IllegalArgumentException
284      *             Thrown when the provided lineSeparator included some base64 characters.
285      * @since 1.4
286      */
287     public Base64(int lineLength, byte[] lineSeparator) {
288         this(lineLength, lineSeparator, false);
289     }
290 
291     /**
292      * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
293      * <p>
294      * When encoding the line length and line separator are given in the constructor, and the encoding table is
295      * STANDARD_ENCODE_TABLE.
296      * </p>
297      * <p>
298      * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
299      * </p>
300      * <p>
301      * When decoding all variants are supported.
302      * </p>
303      *
304      * @param lineLength
305      *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
306      *            If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
307      * @param lineSeparator
308      *            Each line of encoded data will end with this sequence of bytes.
309      * @param urlSafe
310      *            Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode
311      *            operations. Decoding seamlessly handles both modes.
312      * @throws IllegalArgumentException
313      *             The provided lineSeparator included some base64 characters. That's not going to work!
314      * @since 1.4
315      */
316     public Base64(int lineLength, byte[] lineSeparator, boolean urlSafe) {
317         if (lineSeparator == null) {
318             lineLength = 0;  // disable chunk-separating
319             lineSeparator = EMPTY_BYTE_ARRAY;  // this just gets ignored
320         }
321         this.lineLength = lineLength > 0 ? (lineLength / 4) * 4 : 0;
322         this.lineSeparator = new byte[lineSeparator.length];
323         System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
324         if (lineLength > 0) {
325             this.encodeSize = 4 + lineSeparator.length;
326         } else {
327             this.encodeSize = 4;
328         }
329         this.decodeSize = this.encodeSize - 1;
330         if (containsBase64Byte(lineSeparator)) {
331             String sep = newStringUtf8(lineSeparator);
332             throw new IllegalArgumentException("lineSeperator must not contain base64 characters: [" + sep + "]");
333         }
334         this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;
335     }
336 
337     /**
338      * Returns our current encode mode. True if we're URL-SAFE, false otherwise.
339      *
340      * @return true if we're in URL-SAFE mode, false otherwise.
341      * @since 1.4
342      */
343     public boolean isUrlSafe() {
344         return this.encodeTable == URL_SAFE_ENCODE_TABLE;
345     }
346 
347     /**
348      * Returns true if this Base64 object has buffered data for reading.
349      *
350      * @return true if there is Base64 object still available for reading.
351      */
352     boolean hasData() {
353         return this.buffer != null;
354     }
355 
356     /**
357      * Returns the amount of buffered data available for reading.
358      *
359      * @return The amount of buffered data available for reading.
360      */
361     int avail() {
362         return buffer != null ? pos - readPos : 0;
363     }
364 
365     /** Doubles our buffer. */
366     private void resizeBuffer() {
367         if (buffer == null) {
368             buffer = new byte[DEFAULT_BUFFER_SIZE];
369             pos = 0;
370             readPos = 0;
371         } else {
372             byte[] b = new byte[buffer.length * DEFAULT_BUFFER_RESIZE_FACTOR];
373             System.arraycopy(buffer, 0, b, 0, buffer.length);
374             buffer = b;
375         }
376     }
377 
378     /**
379      * Extracts buffered data into the provided byte[] array, starting at position bPos, up to a maximum of bAvail
380      * bytes. Returns how many bytes were actually extracted.
381      *
382      * @param b
383      *            byte[] array to extract the buffered data into.
384      * @param bPos
385      *            position in byte[] array to start extraction at.
386      * @param bAvail
387      *            amount of bytes we're allowed to extract. We may extract fewer (if fewer are available).
388      * @return The number of bytes successfully extracted into the provided byte[] array.
389      */
390     int readResults(byte[] b, int bPos, int bAvail) {
391         if (buffer != null) {
392             int len = Math.min(avail(), bAvail);
393             if (buffer != b) {
394                 System.arraycopy(buffer, readPos, b, bPos, len);
395                 readPos += len;
396                 if (readPos >= pos) {
397                     buffer = null;
398                 }
399             } else {
400                 // Re-using the original consumer's output array is only
401                 // allowed for one round.
402                 buffer = null;
403             }
404             return len;
405         }
406         return eof ? -1 : 0;
407     }
408 
409     /**
410      * Sets the streaming buffer. This is a small optimization where we try to buffer directly to the consumer's output
411      * array for one round (if the consumer calls this method first) instead of starting our own buffer.
412      *
413      * @param out
414      *            byte[] array to buffer directly to.
415      * @param outPos
416      *            Position to start buffering into.
417      * @param outAvail
418      *            Amount of bytes available for direct buffering.
419      */
420     void setInitialBuffer(byte[] out, int outPos, int outAvail) {
421         // We can re-use consumer's original output array under
422         // special circumstances, saving on some System.arraycopy().
423         if (out != null && out.length == outAvail) {
424             buffer = out;
425             pos = outPos;
426             readPos = outPos;
427         }
428     }
429 
430     /**
431      * <p>
432      * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with
433      * the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, so flush last
434      * remaining bytes (if not multiple of 3).
435      * </p>
436      * <p>
437      * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
438      * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
439      * </p>
440      *
441      * @param in
442      *            byte[] array of binary data to base64 encode.
443      * @param inPos
444      *            Position to start reading data from.
445      * @param inAvail
446      *            Amount of bytes available from input for encoding.
447      */
448     void encode(byte[] in, int inPos, int inAvail) {
449         if (eof) {
450             return;
451         }
452         // inAvail < 0 is how we're informed of EOF in the underlying data we're
453         // encoding.
454         if (inAvail < 0) {
455             eof = true;
456             if (buffer == null || buffer.length - pos < encodeSize) {
457                 resizeBuffer();
458             }
459             switch (modulus) {
460                 case 1 :
461                     buffer[pos++] = encodeTable[(x >> 2) & MASK_6BITS];
462                     buffer[pos++] = encodeTable[(x << 4) & MASK_6BITS];
463                     // URL-SAFE skips the padding to further reduce size.
464                     if (encodeTable == STANDARD_ENCODE_TABLE) {
465                         buffer[pos++] = PAD;
466                         buffer[pos++] = PAD;
467                     }
468                     break;
469 
470                 case 2 :
471                     buffer[pos++] = encodeTable[(x >> 10) & MASK_6BITS];
472                     buffer[pos++] = encodeTable[(x >> 4) & MASK_6BITS];
473                     buffer[pos++] = encodeTable[(x << 2) & MASK_6BITS];
474                     // URL-SAFE skips the padding to further reduce size.
475                     if (encodeTable == STANDARD_ENCODE_TABLE) {
476                         buffer[pos++] = PAD;
477                     }
478                     break;
479                 default:
480                     break;  // other values ignored
481             }
482             if (lineLength > 0 && pos > 0) {
483                 System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
484                 pos += lineSeparator.length;
485             }
486         } else {
487             for (int i = 0; i < inAvail; i++) {
488                 if (buffer == null || buffer.length - pos < encodeSize) {
489                     resizeBuffer();
490                 }
491                 modulus = (++modulus) % 3;
492                 int b = in[inPos++];
493                 if (b < 0) {
494                     b += 256;
495                 }
496                 x = (x << 8) + b;
497                 if (0 == modulus) {
498                     buffer[pos++] = encodeTable[(x >> 18) & MASK_6BITS];
499                     buffer[pos++] = encodeTable[(x >> 12) & MASK_6BITS];
500                     buffer[pos++] = encodeTable[(x >> 6) & MASK_6BITS];
501                     buffer[pos++] = encodeTable[x & MASK_6BITS];
502                     currentLinePos += 4;
503                     if (lineLength > 0 && lineLength <= currentLinePos) {
504                         System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
505                         pos += lineSeparator.length;
506                         currentLinePos = 0;
507                     }
508                 }
509             }
510         }
511     }
512 
513     /**
514      * <p>
515      * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once
516      * with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1"
517      * call is not necessary when decoding, but it doesn't hurt, either.
518      * </p>
519      * <p>
520      * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are
521      * silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in,
522      * garbage-out philosophy: it will not check the provided data for validity.
523      * </p>
524      * <p>
525      * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
526      * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
527      * </p>
528      *
529      * @param in
530      *            byte[] array of ascii data to base64 decode.
531      * @param inPos
532      *            Position to start reading data from.
533      * @param inAvail
534      *            Amount of bytes available from input for encoding.
535      */
536     void decode(byte[] in, int inPos, int inAvail) {
537         if (eof) {
538             return;
539         }
540         if (inAvail < 0) {
541             eof = true;
542         }
543         for (int i = 0; i < inAvail; i++) {
544             if (buffer == null || buffer.length - pos < decodeSize) {
545                 resizeBuffer();
546             }
547             byte b = in[inPos++];
548             if (b == PAD) {
549                 // We're done.
550                 eof = true;
551                 break;
552             } else {
553                 if (b >= 0 && b < DECODE_TABLE.length) {
554                     int result = DECODE_TABLE[b];
555                     if (result >= 0) {
556                         modulus = (++modulus) % 4;
557                         x = (x << 6) + result;
558                         if (modulus == 0) {
559                             buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
560                             buffer[pos++] = (byte) ((x >> 8) & MASK_8BITS);
561                             buffer[pos++] = (byte) (x & MASK_8BITS);
562                         }
563                     }
564                 }
565             }
566         }
567 
568         // Two forms of EOF as far as base64 decoder is concerned: actual
569         // EOF (-1) and first time '=' character is encountered in stream.
570         // This approach makes the '=' padding characters completely optional.
571         if (eof && modulus != 0) {
572             x = x << 6;
573             switch (modulus) {
574                 case 2 :
575                     x = x << 6;
576                     buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
577                     break;
578                 case 3 :
579                     buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
580                     buffer[pos++] = (byte) ((x >> 8) & MASK_8BITS);
581                     break;
582                 default:
583                     break;  // other values ignored
584             }
585         }
586     }
587 
588     /**
589      * Returns whether or not the <code>octet</code> is in the base 64 alphabet.
590      *
591      * @param octet
592      *            The value to test
593      * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
594      * @since 1.4
595      */
596     public static boolean isBase64(byte octet) {
597         return octet == PAD || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1);
598     }
599 
600     /**
601      * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the
602      * method treats whitespace as valid.
603      *
604      * @param arrayOctet
605      *            byte array to test
606      * @return <code>true</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
607      *         false, otherwise
608      */
609     public static boolean isArrayByteBase64(byte[] arrayOctet) {
610         for (int i = 0; i < arrayOctet.length; i++) {
611             if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) {
612                 return false;
613             }
614         }
615         return true;
616     }
617 
618     /**
619      * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
620      *
621      * @param arrayOctet
622      *            byte array to test
623      * @return <code>true</code> if any byte is a valid character in the Base64 alphabet; false herwise
624      */
625     private static boolean containsBase64Byte(byte[] arrayOctet) {
626         for (byte element : arrayOctet)
627         {
628             if (isBase64(element)) {
629                 return true;
630             }
631         }
632         return false;
633     }
634 
635     /**
636      * Encodes binary data using the base64 algorithm but does not chunk the output.
637      *
638      * @param binaryData
639      *            binary data to encode
640      * @return byte[] containing Base64 characters in their UTF-8 representation.
641      */
642     public static byte[] encodeBase64(byte[] binaryData) {
643         return encodeBase64(binaryData, false);
644     }
645 
646     /**
647      * Encodes binary data using the base64 algorithm into 76 character blocks separated by CRLF.
648      * <p>
649      * For a non-chunking version, see {@link #encodeBase64StringUnChunked(byte[])}.
650      *
651      * @param binaryData
652      *            binary data to encode
653      * @return String containing Base64 characters.
654      * @since 1.4
655      */
656     public static String encodeBase64String(byte[] binaryData) {
657         return newStringUtf8(encodeBase64(binaryData, true));
658     }
659 
660     /**
661      * Encodes binary data using the base64 algorithm, without using chunking.
662      * <p>
663      * For a chunking version, see {@link #encodeBase64String(byte[])}.
664      *
665      * @param binaryData
666      *            binary data to encode
667      * @return String containing Base64 characters.
668      * @since 3.2
669      */
670     public static String encodeBase64StringUnChunked(byte[] binaryData) {
671         return newStringUtf8(encodeBase64(binaryData, false));
672     }
673 
674     /**
675      * Encodes binary data using the base64 algorithm.
676      *
677      * @param binaryData
678      *            binary data to encode
679      * @param useChunking whether to split the output into chunks
680      * @return String containing Base64 characters.
681      * @since 3.2
682      */
683     public static String encodeBase64String(byte[] binaryData, boolean useChunking) {
684         return newStringUtf8(encodeBase64(binaryData, useChunking));
685     }
686 
687     /**
688      * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
689      * url-safe variation emits - and _ instead of + and / characters.
690      *
691      * @param binaryData
692      *            binary data to encode
693      * @return byte[] containing Base64 characters in their UTF-8 representation.
694      * @since 1.4
695      */
696     public static byte[] encodeBase64URLSafe(byte[] binaryData) {
697         return encodeBase64(binaryData, false, true);
698     }
699 
700     /**
701      * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
702      * url-safe variation emits - and _ instead of + and / characters.
703      *
704      * @param binaryData
705      *            binary data to encode
706      * @return String containing Base64 characters
707      * @since 1.4
708      */
709     public static String encodeBase64URLSafeString(byte[] binaryData) {
710         return newStringUtf8(encodeBase64(binaryData, false, true));
711     }
712 
713     /**
714      * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
715      *
716      * @param binaryData
717      *            binary data to encode
718      * @return Base64 characters chunked in 76 character blocks
719      */
720     public static byte[] encodeBase64Chunked(byte[] binaryData) {
721         return encodeBase64(binaryData, true);
722     }
723 
724     /**
725      * Decodes a String containing containing characters in the Base64 alphabet.
726      *
727      * @param pArray
728      *            A String containing Base64 character data
729      * @return a byte array containing binary data
730      * @since 1.4
731      */
732     public byte[] decode(String pArray) {
733         return decode(getBytesUtf8(pArray));
734     }
735 
736     private byte[] getBytesUtf8(String pArray) {
737         try {
738             return pArray.getBytes("UTF8");
739         } catch (UnsupportedEncodingException e) {
740             throw new RuntimeException(e);
741         }
742     }
743 
744     /**
745      * Decodes a byte[] containing containing characters in the Base64 alphabet.
746      *
747      * @param pArray
748      *            A byte array containing Base64 character data
749      * @return a byte array containing binary data
750      */
751     public byte[] decode(byte[] pArray) {
752         reset();
753         if (pArray == null || pArray.length == 0) {
754             return pArray;
755         }
756         long len = (pArray.length * 3) / 4;
757         byte[] buf = new byte[(int) len];
758         setInitialBuffer(buf, 0, buf.length);
759         decode(pArray, 0, pArray.length);
760         decode(pArray, 0, -1); // Notify decoder of EOF.
761 
762         // Would be nice to just return buf (like we sometimes do in the encode
763         // logic), but we have no idea what the line-length was (could even be
764         // variable).  So we cannot determine ahead of time exactly how big an
765         // array is necessary.  Hence the need to construct a 2nd byte array to
766         // hold the final result:
767 
768         byte[] result = new byte[pos];
769         readResults(result, 0, result.length);
770         return result;
771     }
772 
773     /**
774      * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
775      *
776      * @param binaryData
777      *            Array containing binary data to encode.
778      * @param isChunked
779      *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
780      * @return Base64-encoded data.
781      * @throws IllegalArgumentException
782      *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
783      */
784     public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
785         return encodeBase64(binaryData, isChunked, false);
786     }
787 
788     /**
789      * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
790      *
791      * @param binaryData
792      *            Array containing binary data to encode.
793      * @param isChunked
794      *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
795      * @param urlSafe
796      *            if <code>true</code> this encoder will emit - and _ instead of the usual + and / characters.
797      * @return Base64-encoded data.
798      * @throws IllegalArgumentException
799      *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
800      * @since 1.4
801      */
802     public static byte[] encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe) {
803         return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);
804     }
805 
806     /**
807      * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
808      *
809      * @param binaryData
810      *            Array containing binary data to encode.
811      * @param isChunked
812      *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
813      * @param urlSafe
814      *            if <code>true</code> this encoder will emit - and _ instead of the usual + and / characters.
815      * @param maxResultSize
816      *            The maximum result size to accept.
817      * @return Base64-encoded data.
818      * @throws IllegalArgumentException
819      *             Thrown when the input array needs an output array bigger than maxResultSize
820      * @since 1.4
821      */
822     public static byte[] encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe, int maxResultSize) {
823         if (binaryData == null || binaryData.length == 0) {
824             return binaryData;
825         }
826 
827         long len = getEncodeLength(binaryData, isChunked ? CHUNK_SIZE : 0, isChunked ? CHUNK_SEPARATOR : EMPTY_BYTE_ARRAY);
828         if (len > maxResultSize) {
829             throw new IllegalArgumentException("Input array too big, the output array would be bigger (" +
830                 len +
831                 ") than the specified maxium size of " +
832                 maxResultSize);
833         }
834 
835         Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);
836         return b64.encode(binaryData);
837     }
838 
839     /**
840      * Decodes a Base64 String into octets
841      *
842      * @param base64String
843      *            String containing Base64 data
844      * @return Array containing decoded data.
845      * @since 1.4
846      */
847     public static byte[] decodeBase64(String base64String) {
848         return new Base64().decode(base64String);
849     }
850 
851     /**
852      * Decodes Base64 data into octets
853      *
854      * @param base64Data
855      *            Byte array containing Base64 data
856      * @return Array containing decoded data.
857      */
858     public static byte[] decodeBase64(byte[] base64Data) {
859         return new Base64().decode(base64Data);
860     }
861 
862 
863 
864     /**
865      * Checks if a byte value is whitespace or not.
866      *
867      * @param byteToCheck
868      *            the byte to check
869      * @return true if byte is whitespace, false otherwise
870      */
871     private static boolean isWhiteSpace(byte byteToCheck) {
872         switch (byteToCheck) {
873             case ' ' :
874             case '\n' :
875             case '\r' :
876             case '\t' :
877                 return true;
878             default :
879                 return false;
880         }
881     }
882 
883     /**
884      * Encodes a byte[] containing binary data, into a String containing characters in the Base64 alphabet.
885      *
886      * @param pArray
887      *            a byte array containing binary data
888      * @return A String containing only Base64 character data
889      * @since 1.4
890      */
891     public String encodeToString(byte[] pArray) {
892         return newStringUtf8(encode(pArray));
893     }
894 
895     private static String newStringUtf8(byte[] encode) {
896         String str = null;
897         try {
898             str = new String(encode, "UTF8");
899         } catch (UnsupportedEncodingException ue) {
900             throw new RuntimeException(ue);
901         }
902         return str;
903     }
904 
905     /**
906      * Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
907      *
908      * @param pArray
909      *            a byte array containing binary data
910      * @return A byte array containing only Base64 character data
911      */
912     public byte[] encode(byte[] pArray) {
913         reset();
914         if (pArray == null || pArray.length == 0) {
915             return pArray;
916         }
917         long len = getEncodeLength(pArray, lineLength, lineSeparator);
918         byte[] buf = new byte[(int) len];
919         setInitialBuffer(buf, 0, buf.length);
920         encode(pArray, 0, pArray.length);
921         encode(pArray, 0, -1); // Notify encoder of EOF.
922         // Encoder might have resized, even though it was unnecessary.
923         if (buffer != buf) {
924             readResults(buf, 0, buf.length);
925         }
926         // In URL-SAFE mode we skip the padding characters, so sometimes our
927         // final length is a bit smaller.
928         if (isUrlSafe() && pos < buf.length) {
929             byte[] smallerBuf = new byte[pos];
930             System.arraycopy(buf, 0, smallerBuf, 0, pos);
931             buf = smallerBuf;
932         }
933         return buf;
934     }
935 
936     /**
937      * Pre-calculates the amount of space needed to base64-encode the supplied array.
938      *
939      * @param pArray byte[] array which will later be encoded
940      * @param chunkSize line-length of the output (<= 0 means no chunking) between each
941      *        chunkSeparator (e.g. CRLF).
942      * @param chunkSeparator the sequence of bytes used to separate chunks of output (e.g. CRLF).
943      *
944      * @return amount of space needed to encoded the supplied array.  Returns
945      *         a long since a max-len array will require Integer.MAX_VALUE + 33%.
946      */
947     private static long getEncodeLength(byte[] pArray, int chunkSize, byte[] chunkSeparator) {
948         // base64 always encodes to multiples of 4.
949         chunkSize = (chunkSize / 4) * 4;
950 
951         long len = (pArray.length * 4) / 3;
952         long mod = len % 4;
953         if (mod != 0) {
954             len += 4 - mod;
955         }
956         if (chunkSize > 0) {
957             boolean lenChunksPerfectly = len % chunkSize == 0;
958             len += (len / chunkSize) * chunkSeparator.length;
959             if (!lenChunksPerfectly) {
960                 len += chunkSeparator.length;
961             }
962         }
963         return len;
964     }
965 
966     // Implementation of integer encoding used for crypto
967     /**
968      * Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
969      *
970      * @param pArray
971      *            a byte array containing base64 character data
972      * @return A BigInteger
973      * @since 1.4
974      */
975     public static BigInteger decodeInteger(byte[] pArray) {
976         return new BigInteger(1, decodeBase64(pArray));
977     }
978 
979     /**
980      * Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
981      *
982      * @param bigInt
983      *            a BigInteger
984      * @return A byte array containing base64 character data
985      * @throws NullPointerException
986      *             if null is passed in
987      * @since 1.4
988      */
989     public static byte[] encodeInteger(BigInteger bigInt) {
990         if (bigInt == null) {
991             throw new NullPointerException("encodeInteger called with null parameter");
992         }
993         return encodeBase64(toIntegerBytes(bigInt), false);
994     }
995 
996     /**
997      * Returns a byte-array representation of a <code>BigInteger</code> without sign bit.
998      *
999      * @param bigInt
1000      *            <code>BigInteger</code> to be converted
1001      * @return a byte array representation of the BigInteger parameter
1002      */
1003     static byte[] toIntegerBytes(BigInteger bigInt) {
1004         int bitlen = bigInt.bitLength();
1005         // round bitlen
1006         bitlen = ((bitlen + 7) >> 3) << 3;
1007         byte[] bigBytes = bigInt.toByteArray();
1008 
1009         if (((bigInt.bitLength() % 8) != 0) && (((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) {
1010             return bigBytes;
1011         }
1012         // set up params for copying everything but sign bit
1013         int startSrc = 0;
1014         int len = bigBytes.length;
1015 
1016         // if bigInt is exactly byte-aligned, just skip signbit in copy
1017         if ((bigInt.bitLength() % 8) == 0) {
1018             startSrc = 1;
1019             len--;
1020         }
1021         int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
1022         byte[] resizedBytes = new byte[bitlen / 8];
1023         System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
1024         return resizedBytes;
1025     }
1026 
1027     /**
1028      * Resets this Base64 object to its initial newly constructed state.
1029      */
1030     private void reset() {
1031         buffer = null;
1032         pos = 0;
1033         readPos = 0;
1034         currentLinePos = 0;
1035         modulus = 0;
1036         eof = false;
1037     }
1038 
1039     // Getters for use in testing
1040 
1041     int getLineLength() {
1042         return lineLength;
1043     }
1044 
1045     byte[] getLineSeparator() {
1046         return lineSeparator.clone();
1047     }
1048 }