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1   package org.springframework.roo.support.util;
2   
3   /**
4    * <p>Encodes and decodes to and from Base64 notation.</p>
5    * <p>Homepage: <a href="http://iharder.net/base64">http://iharder.net/base64</a>.</p>
6    * 
7    * <p>Example:</p>
8    * 
9    * <code>String encoded = Base64.encode( myByteArray );</code>
10   * <br />
11   * <code>byte[] myByteArray = Base64.decode( encoded );</code>
12   *
13   * <p>The <tt>options</tt> parameter, which appears in a few places, is used to pass 
14   * several pieces of information to the encoder. In the "higher level" methods such as 
15   * encodeBytes( bytes, options ) the options parameter can be used to indicate such 
16   * things as first gzipping the bytes before encoding them, not inserting linefeeds,
17   * and encoding using the URL-safe and Ordered dialects.</p>
18   *
19   * <p>Note, according to <a href="http://www.faqs.org/rfcs/rfc3548.html">RFC3548</a>,
20   * Section 2.1, implementations should not add line feeds unless explicitly told
21   * to do so. I've got Base64 set to this behavior now, although earlier versions
22   * broke lines by default.</p>
23   *
24   * <p>The constants defined in Base64 can be OR-ed together to combine options, so you 
25   * might make a call like this:</p>
26   *
27   * <code>String encoded = Base64.encodeBytes( mybytes, Base64.GZIP | Base64.DO_BREAK_LINES );</code>
28   * <p>to compress the data before encoding it and then making the output have newline characters.</p>
29   * <p>Also...</p>
30   * <code>String encoded = Base64.encodeBytes( crazyString.getBytes() );</code>
31   *
32   *
33   *
34   * <p>
35   * Change Log:
36   * </p>
37   * <ul>
38   *  <li>v2.3.7 - Fixed subtle bug when base 64 input stream contained the
39   *   value 01111111, which is an invalid base 64 character but should not
40   *   throw an ArrayIndexOutOfBoundsException either. Led to discovery of
41   *   mishandling (or potential for better handling) of other bad input
42   *   characters. You should now get an IOException if you try decoding
43   *   something that has bad characters in it.</li>
44   *  <li>v2.3.6 - Fixed bug when breaking lines and the final byte of the encoded
45   *   string ended in the last column; the buffer was not properly shrunk and
46   *   contained an extra (null) byte that made it into the string.</li>
47   *  <li>v2.3.5 - Fixed bug in {@link #encodeFromFile} where estimated buffer size
48   *   was wrong for files of size 31, 34, and 37 bytes.</li>
49   *  <li>v2.3.4 - Fixed bug when working with gzipped streams whereby flushing
50   *   the Base64.OutputStream closed the Base64 encoding (by padding with equals
51   *   signs) too soon. Also added an option to suppress the automatic decoding
52   *   of gzipped streams. Also added experimental support for specifying a
53   *   class loader when using the
54   *   {@link #decodeToObject(java.lang.String, int, java.lang.ClassLoader)}
55   *   method.</li>
56   *  <li>v2.3.3 - Changed default char encoding to US-ASCII which reduces the internal Java
57   *   footprint with its CharEncoders and so forth. Fixed some javadocs that were
58   *   inconsistent. Removed imports and specified things like java.io.IOException
59   *   explicitly inline.</li>
60   *  <li>v2.3.2 - Reduced memory footprint! Finally refined the "guessing" of how big the
61   *   final encoded data will be so that the code doesn't have to create two output
62   *   arrays: an oversized initial one and then a final, exact-sized one. Big win
63   *   when using the {@link #encodeBytesToBytes(byte[])} family of methods (and not
64   *   using the gzip options which uses a different mechanism with streams and stuff).</li>
65   *  <li>v2.3.1 - Added {@link #encodeBytesToBytes(byte[], int, int, int)} and some
66   *   similar helper methods to be more efficient with memory by not returning a
67   *   String but just a byte array.</li>
68   *  <li>v2.3 - <strong>This is not a drop-in replacement!</strong> This is two years of comments
69   *   and bug fixes queued up and finally executed. Thanks to everyone who sent
70   *   me stuff, and I'm sorry I wasn't able to distribute your fixes to everyone else.
71   *   Much bad coding was cleaned up including throwing exceptions where necessary 
72   *   instead of returning null values or something similar. Here are some changes
73   *   that may affect you:
74   *   <ul>
75   *    <li><em>Does not break lines, by default.</em> This is to keep in compliance with
76   *      <a href="http://www.faqs.org/rfcs/rfc3548.html">RFC3548</a>.</li>
77   *    <li><em>Throws exceptions instead of returning null values.</em> Because some operations
78   *      (especially those that may permit the GZIP option) use IO streams, there
79   *      is a possiblity of an java.io.IOException being thrown. After some discussion and
80   *      thought, I've changed the behavior of the methods to throw java.io.IOExceptions
81   *      rather than return null if ever there's an error. I think this is more
82   *      appropriate, though it will require some changes to your code. Sorry,
83   *      it should have been done this way to begin with.</li>
84   *    <li><em>Removed all references to System.out, System.err, and the like.</em>
85   *      Shame on me. All I can say is sorry they were ever there.</li>
86   *    <li><em>Throws NullPointerExceptions and IllegalArgumentExceptions</em> as needed
87   *      such as when passed arrays are null or offsets are invalid.</li>
88   *    <li>Cleaned up as much javadoc as I could to avoid any javadoc warnings.
89   *      This was especially annoying before for people who were thorough in their
90   *      own projects and then had gobs of javadoc warnings on this file.</li>
91   *   </ul>
92   *  <li>v2.2.1 - Fixed bug using URL_SAFE and ORDERED encodings. Fixed bug
93   *   when using very small files (~&lt; 40 bytes).</li>
94   *  <li>v2.2 - Added some helper methods for encoding/decoding directly from
95   *   one file to the next. Also added a main() method to support command line
96   *   encoding/decoding from one file to the next. Also added these Base64 dialects:
97   *   <ol>
98   *   <li>The default is RFC3548 format.</li>
99   *   <li>Calling Base64.setFormat(Base64.BASE64_FORMAT.URLSAFE_FORMAT) generates
100  *   URL and file name friendly format as described in Section 4 of RFC3548.
101  *   http://www.faqs.org/rfcs/rfc3548.html</li>
102  *   <li>Calling Base64.setFormat(Base64.BASE64_FORMAT.ORDERED_FORMAT) generates
103  *   URL and file name friendly format that preserves lexical ordering as described
104  *   in http://www.faqs.org/qa/rfcc-1940.html</li>
105  *   </ol>
106  *   Special thanks to Jim Kellerman at <a href="http://www.powerset.com/">http://www.powerset.com/</a>
107  *   for contributing the new Base64 dialects.
108  *  </li>
109  * 
110  *  <li>v2.1 - Cleaned up javadoc comments and unused variables and methods. Added
111  *   some convenience methods for reading and writing to and from files.</li>
112  *  <li>v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems
113  *   with other encodings (like EBCDIC).</li>
114  *  <li>v2.0.1 - Fixed an error when decoding a single byte, that is, when the
115  *   encoded data was a single byte.</li>
116  *  <li>v2.0 - I got rid of methods that used booleans to set options. 
117  *   Now everything is more consolidated and cleaner. The code now detects
118  *   when data that's being decoded is gzip-compressed and will decompress it
119  *   automatically. Generally things are cleaner. You'll probably have to
120  *   change some method calls that you were making to support the new
121  *   options format (<tt>int</tt>s that you "OR" together).</li>
122  *  <li>v1.5.1 - Fixed bug when decompressing and decoding to a             
123  *   byte[] using <tt>decode( String s, boolean gzipCompressed )</tt>.      
124  *   Added the ability to "suspend" encoding in the Output Stream so        
125  *   you can turn on and off the encoding if you need to embed base64       
126  *   data in an otherwise "normal" stream (like an XML file).</li>  
127  *  <li>v1.5 - Output stream pases on flush() command but doesn't do anything itself.
128  *      This helps when using GZIP streams.
129  *      Added the ability to GZip-compress objects before encoding them.</li>
130  *  <li>v1.4 - Added helper methods to read/write files.</li>
131  *  <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li>
132  *  <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream
133  *      where last buffer being read, if not completely full, was not returned.</li>
134  *  <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.</li>
135  *  <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
136  * </ul>
137  *
138  * <p>
139  * I am placing this code in the Public Domain. Do with it as you will.
140  * This software comes with no guarantees or warranties but with
141  * plenty of well-wishing instead!
142  * Please visit <a href="http://iharder.net/base64">http://iharder.net/base64</a>
143  * periodically to check for updates or to contribute improvements.
144  * </p>
145  *
146  * @author Robert Harder
147  * @author [email protected]
148  * @version 2.3.7
149  */
150 public class Base64
151 {
152     
153 /* ********  P U B L I C   F I E L D S  ******** */   
154     
155     
156     /** No options specified. Value is zero. */
157     public final static int NO_OPTIONS = 0;
158     
159     /** Specify encoding in first bit. Value is one. */
160     public final static int ENCODE = 1;
161     
162     
163     /** Specify decoding in first bit. Value is zero. */
164     public final static int DECODE = 0;
165     
166 
167     /** Specify that data should be gzip-compressed in second bit. Value is two. */
168     public final static int GZIP = 2;
169 
170     /** Specify that gzipped data should <em>not</em> be automatically gunzipped. */
171     public final static int DONT_GUNZIP = 4;
172     
173     
174     /** Do break lines when encoding. Value is 8. */
175     public final static int DO_BREAK_LINES = 8;
176 	
177     /** 
178      * Encode using Base64-like encoding that is URL- and Filename-safe as described
179      * in Section 4 of RFC3548: 
180      * <a href="http://www.faqs.org/rfcs/rfc3548.html">http://www.faqs.org/rfcs/rfc3548.html</a>.
181      * It is important to note that data encoded this way is <em>not</em> officially valid Base64, 
182      * or at the very least should not be called Base64 without also specifying that is
183      * was encoded using the URL- and Filename-safe dialect.
184      */
185      public final static int URL_SAFE = 16;
186 
187 
188      /**
189       * Encode using the special "ordered" dialect of Base64 described here:
190       * <a href="http://www.faqs.org/qa/rfcc-1940.html">http://www.faqs.org/qa/rfcc-1940.html</a>.
191       */
192      public final static int ORDERED = 32;
193     
194     
195 /* ********  P R I V A T E   F I E L D S  ******** */  
196     
197     
198     /** Maximum line length (76) of Base64 output. */
199     private final static int MAX_LINE_LENGTH = 76;
200     
201     
202     /** The equals sign (=) as a byte. */
203     private final static byte EQUALS_SIGN = (byte)'=';
204     
205     
206     /** The new line character (\n) as a byte. */
207     private final static byte NEW_LINE = (byte)'\n';
208     
209     
210     /** Preferred encoding. */
211     private final static String PREFERRED_ENCODING = "US-ASCII";
212     
213 	
214     private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding
215     private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding
216 	
217 	
218 /* ********  S T A N D A R D   B A S E 6 4   A L P H A B E T  ******** */	
219     
220     /** The 64 valid Base64 values. */
221     /* Host platform me be something funny like EBCDIC, so we hardcode these values. */
222     private final static byte[] _STANDARD_ALPHABET = {
223         (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
224         (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
225         (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', 
226         (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
227         (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
228         (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
229         (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', 
230         (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z',
231         (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', 
232         (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/'
233     };
234 	
235     
236     /** 
237      * Translates a Base64 value to either its 6-bit reconstruction value
238      * or a negative number indicating some other meaning.
239      **/
240     private final static byte[] _STANDARD_DECODABET = {
241         -9,-9,-9,-9,-9,-9,-9,-9,-9,                 // Decimal  0 -  8
242         -5,-5,                                      // Whitespace: Tab and Linefeed
243         -9,-9,                                      // Decimal 11 - 12
244         -5,                                         // Whitespace: Carriage Return
245         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 14 - 26
246         -9,-9,-9,-9,-9,                             // Decimal 27 - 31
247         -5,                                         // Whitespace: Space
248         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,              // Decimal 33 - 42
249         62,                                         // Plus sign at decimal 43
250         -9,-9,-9,                                   // Decimal 44 - 46
251         63,                                         // Slash at decimal 47
252         52,53,54,55,56,57,58,59,60,61,              // Numbers zero through nine
253         -9,-9,-9,                                   // Decimal 58 - 60
254         -1,                                         // Equals sign at decimal 61
255         -9,-9,-9,                                      // Decimal 62 - 64
256         0,1,2,3,4,5,6,7,8,9,10,11,12,13,            // Letters 'A' through 'N'
257         14,15,16,17,18,19,20,21,22,23,24,25,        // Letters 'O' through 'Z'
258         -9,-9,-9,-9,-9,-9,                          // Decimal 91 - 96
259         26,27,28,29,30,31,32,33,34,35,36,37,38,     // Letters 'a' through 'm'
260         39,40,41,42,43,44,45,46,47,48,49,50,51,     // Letters 'n' through 'z'
261         -9,-9,-9,-9,-9                              // Decimal 123 - 127
262         ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,       // Decimal 128 - 139
263         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
264         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
265         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
266         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
267         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
268         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
269         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
270         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
271         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 
272     };
273 	
274 	
275 /* ********  U R L   S A F E   B A S E 6 4   A L P H A B E T  ******** */
276 	
277     /**
278      * Used in the URL- and Filename-safe dialect described in Section 4 of RFC3548: 
279      * <a href="http://www.faqs.org/rfcs/rfc3548.html">http://www.faqs.org/rfcs/rfc3548.html</a>.
280      * Notice that the last two bytes become "hyphen" and "underscore" instead of "plus" and "slash."
281      */
282     private final static byte[] _URL_SAFE_ALPHABET = {
283       (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
284       (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
285       (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', 
286       (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
287       (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
288       (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
289       (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', 
290       (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z',
291       (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', 
292       (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'-', (byte)'_'
293     };
294 	
295     /**
296      * Used in decoding URL- and Filename-safe dialects of Base64.
297      */
298     private final static byte[] _URL_SAFE_DECODABET = {
299       -9,-9,-9,-9,-9,-9,-9,-9,-9,                 // Decimal  0 -  8
300       -5,-5,                                      // Whitespace: Tab and Linefeed
301       -9,-9,                                      // Decimal 11 - 12
302       -5,                                         // Whitespace: Carriage Return
303       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 14 - 26
304       -9,-9,-9,-9,-9,                             // Decimal 27 - 31
305       -5,                                         // Whitespace: Space
306       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,              // Decimal 33 - 42
307       -9,                                         // Plus sign at decimal 43
308       -9,                                         // Decimal 44
309       62,                                         // Minus sign at decimal 45
310       -9,                                         // Decimal 46
311       -9,                                         // Slash at decimal 47
312       52,53,54,55,56,57,58,59,60,61,              // Numbers zero through nine
313       -9,-9,-9,                                   // Decimal 58 - 60
314       -1,                                         // Equals sign at decimal 61
315       -9,-9,-9,                                   // Decimal 62 - 64
316       0,1,2,3,4,5,6,7,8,9,10,11,12,13,            // Letters 'A' through 'N'
317       14,15,16,17,18,19,20,21,22,23,24,25,        // Letters 'O' through 'Z'
318       -9,-9,-9,-9,                                // Decimal 91 - 94
319       63,                                         // Underscore at decimal 95
320       -9,                                         // Decimal 96
321       26,27,28,29,30,31,32,33,34,35,36,37,38,     // Letters 'a' through 'm'
322       39,40,41,42,43,44,45,46,47,48,49,50,51,     // Letters 'n' through 'z'
323       -9,-9,-9,-9,-9                              // Decimal 123 - 127
324       ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 128 - 139
325       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
326       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
327       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
328       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
329       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
330       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
331       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
332       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
333       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 
334     };
335 
336 
337 
338 /* ********  O R D E R E D   B A S E 6 4   A L P H A B E T  ******** */
339 
340     /**
341      * I don't get the point of this technique, but someone requested it,
342      * and it is described here:
343      * <a href="http://www.faqs.org/qa/rfcc-1940.html">http://www.faqs.org/qa/rfcc-1940.html</a>.
344      */
345     private final static byte[] _ORDERED_ALPHABET = {
346       (byte)'-',
347       (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4',
348       (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9',
349       (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
350       (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
351       (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
352       (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
353       (byte)'_',
354       (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
355       (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
356       (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
357       (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z'
358     };
359 	
360     /**
361      * Used in decoding the "ordered" dialect of Base64.
362      */
363     private final static byte[] _ORDERED_DECODABET = {
364       -9,-9,-9,-9,-9,-9,-9,-9,-9,                 // Decimal  0 -  8
365       -5,-5,                                      // Whitespace: Tab and Linefeed
366       -9,-9,                                      // Decimal 11 - 12
367       -5,                                         // Whitespace: Carriage Return
368       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 14 - 26
369       -9,-9,-9,-9,-9,                             // Decimal 27 - 31
370       -5,                                         // Whitespace: Space
371       -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,              // Decimal 33 - 42
372       -9,                                         // Plus sign at decimal 43
373       -9,                                         // Decimal 44
374       0,                                          // Minus sign at decimal 45
375       -9,                                         // Decimal 46
376       -9,                                         // Slash at decimal 47
377       1,2,3,4,5,6,7,8,9,10,                       // Numbers zero through nine
378       -9,-9,-9,                                   // Decimal 58 - 60
379       -1,                                         // Equals sign at decimal 61
380       -9,-9,-9,                                   // Decimal 62 - 64
381       11,12,13,14,15,16,17,18,19,20,21,22,23,     // Letters 'A' through 'M'
382       24,25,26,27,28,29,30,31,32,33,34,35,36,     // Letters 'N' through 'Z'
383       -9,-9,-9,-9,                                // Decimal 91 - 94
384       37,                                         // Underscore at decimal 95
385       -9,                                         // Decimal 96
386       38,39,40,41,42,43,44,45,46,47,48,49,50,     // Letters 'a' through 'm'
387       51,52,53,54,55,56,57,58,59,60,61,62,63,     // Letters 'n' through 'z'
388       -9,-9,-9,-9,-9                                 // Decimal 123 - 127
389        ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 128 - 139
390         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
391         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
392         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
393         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
394         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
395         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
396         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
397         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
398         -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 
399     };
400 
401 	
402 /* ********  D E T E R M I N E   W H I C H   A L H A B E T  ******** */
403 
404 
405     /**
406      * Returns one of the _SOMETHING_ALPHABET byte arrays depending on
407      * the options specified.
408      * It's possible, though silly, to specify ORDERED <b>and</b> URLSAFE
409      * in which case one of them will be picked, though there is
410      * no guarantee as to which one will be picked.
411      */
412     private final static byte[] getAlphabet( int options ) {
413         if ((options & URL_SAFE) == URL_SAFE) {
414             return _URL_SAFE_ALPHABET;
415         } else if ((options & ORDERED) == ORDERED) {
416             return _ORDERED_ALPHABET;
417         } else {
418             return _STANDARD_ALPHABET;
419         }
420     }	// end getAlphabet
421 
422 
423     /**
424      * Returns one of the _SOMETHING_DECODABET byte arrays depending on
425      * the options specified.
426      * It's possible, though silly, to specify ORDERED and URL_SAFE
427      * in which case one of them will be picked, though there is
428      * no guarantee as to which one will be picked.
429      */
430     private final static byte[] getDecodabet( int options ) {
431         if( (options & URL_SAFE) == URL_SAFE) {
432             return _URL_SAFE_DECODABET;
433         } else if ((options & ORDERED) == ORDERED) {
434             return _ORDERED_DECODABET;
435         } else {
436             return _STANDARD_DECODABET;
437         }
438     }	// end getAlphabet
439 
440 
441     
442     /** Defeats instantiation. */
443     private Base64(){}
444     
445 
446     
447     
448 /* ********  E N C O D I N G   M E T H O D S  ******** */    
449     
450     
451     /**
452      * Encodes up to the first three bytes of array <var>threeBytes</var>
453      * and returns a four-byte array in Base64 notation.
454      * The actual number of significant bytes in your array is
455      * given by <var>numSigBytes</var>.
456      * The array <var>threeBytes</var> needs only be as big as
457      * <var>numSigBytes</var>.
458      * Code can reuse a byte array by passing a four-byte array as <var>b4</var>.
459      *
460      * @param b4 A reusable byte array to reduce array instantiation
461      * @param threeBytes the array to convert
462      * @param numSigBytes the number of significant bytes in your array
463      * @return four byte array in Base64 notation.
464      * @since 1.5.1
465      */
466     private static byte[] encode3to4( byte[] b4, byte[] threeBytes, int numSigBytes, int options ) {
467         encode3to4( threeBytes, 0, numSigBytes, b4, 0, options );
468         return b4;
469     }   // end encode3to4
470 
471     
472     /**
473      * <p>Encodes up to three bytes of the array <var>source</var>
474      * and writes the resulting four Base64 bytes to <var>destination</var>.
475      * The source and destination arrays can be manipulated
476      * anywhere along their length by specifying 
477      * <var>srcOffset</var> and <var>destOffset</var>.
478      * This method does not check to make sure your arrays
479      * are large enough to accomodate <var>srcOffset</var> + 3 for
480      * the <var>source</var> array or <var>destOffset</var> + 4 for
481      * the <var>destination</var> array.
482      * The actual number of significant bytes in your array is
483      * given by <var>numSigBytes</var>.</p>
484 	 * <p>This is the lowest level of the encoding methods with
485 	 * all possible parameters.</p>
486      *
487      * @param source the array to convert
488      * @param srcOffset the index where conversion begins
489      * @param numSigBytes the number of significant bytes in your array
490      * @param destination the array to hold the conversion
491      * @param destOffset the index where output will be put
492      * @return the <var>destination</var> array
493      * @since 1.3
494      */
495     private static byte[] encode3to4( 
496     byte[] source, int srcOffset, int numSigBytes,
497     byte[] destination, int destOffset, int options ) {
498         
499 	byte[] ALPHABET = getAlphabet( options ); 
500 	
501         //           1         2         3  
502         // 01234567890123456789012345678901 Bit position
503         // --------000000001111111122222222 Array position from threeBytes
504         // --------|    ||    ||    ||    | Six bit groups to index ALPHABET
505         //          >>18  >>12  >> 6  >> 0  Right shift necessary
506         //                0x3f  0x3f  0x3f  Additional AND
507         
508         // Create buffer with zero-padding if there are only one or two
509         // significant bytes passed in the array.
510         // We have to shift left 24 in order to flush out the 1's that appear
511         // when Java treats a value as negative that is cast from a byte to an int.
512         int inBuff =   ( numSigBytes > 0 ? ((source[ srcOffset     ] << 24) >>>  8) : 0 )
513                      | ( numSigBytes > 1 ? ((source[ srcOffset + 1 ] << 24) >>> 16) : 0 )
514                      | ( numSigBytes > 2 ? ((source[ srcOffset + 2 ] << 24) >>> 24) : 0 );
515 
516         switch( numSigBytes )
517         {
518             case 3:
519                 destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
520                 destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
521                 destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>>  6) & 0x3f ];
522                 destination[ destOffset + 3 ] = ALPHABET[ (inBuff       ) & 0x3f ];
523                 return destination;
524                 
525             case 2:
526                 destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
527                 destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
528                 destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>>  6) & 0x3f ];
529                 destination[ destOffset + 3 ] = EQUALS_SIGN;
530                 return destination;
531                 
532             case 1:
533                 destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
534                 destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
535                 destination[ destOffset + 2 ] = EQUALS_SIGN;
536                 destination[ destOffset + 3 ] = EQUALS_SIGN;
537                 return destination;
538                 
539             default:
540                 return destination;
541         }   // end switch
542     }   // end encode3to4
543 
544 
545 
546     /**
547      * Performs Base64 encoding on the <code>raw</code> ByteBuffer,
548      * writing it to the <code>encoded</code> ByteBuffer.
549      * This is an experimental feature. Currently it does not
550      * pass along any options (such as {@link #DO_BREAK_LINES}
551      * or {@link #GZIP}.
552      *
553      * @param raw input buffer
554      * @param encoded output buffer
555      * @since 2.3
556      */
557     public static void encode( java.nio.ByteBuffer raw, java.nio.ByteBuffer encoded ){
558         byte[] raw3 = new byte[3];
559         byte[] enc4 = new byte[4];
560 
561         while( raw.hasRemaining() ){
562             int rem = Math.min(3,raw.remaining());
563             raw.get(raw3,0,rem);
564             Base64.encode3to4(enc4, raw3, rem, Base64.NO_OPTIONS );
565             encoded.put(enc4);
566         }   // end input remaining
567     }
568 
569 
570     /**
571      * Performs Base64 encoding on the <code>raw</code> ByteBuffer,
572      * writing it to the <code>encoded</code> CharBuffer.
573      * This is an experimental feature. Currently it does not
574      * pass along any options (such as {@link #DO_BREAK_LINES}
575      * or {@link #GZIP}.
576      *
577      * @param raw input buffer
578      * @param encoded output buffer
579      * @since 2.3
580      */
581     public static void encode( java.nio.ByteBuffer raw, java.nio.CharBuffer encoded ){
582         byte[] raw3 = new byte[3];
583         byte[] enc4 = new byte[4];
584 
585         while( raw.hasRemaining() ){
586             int rem = Math.min(3,raw.remaining());
587             raw.get(raw3,0,rem);
588             Base64.encode3to4(enc4, raw3, rem, Base64.NO_OPTIONS );
589             for( int i = 0; i < 4; i++ ){
590                 encoded.put( (char)(enc4[i] & 0xFF) );
591             }
592         }   // end input remaining
593     }
594 
595 
596     
597     
598     /**
599      * Serializes an object and returns the Base64-encoded
600      * version of that serialized object.  
601      *  
602      * <p>As of v 2.3, if the object
603      * cannot be serialized or there is another error,
604      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
605      * In earlier versions, it just returned a null value, but
606      * in retrospect that's a pretty poor way to handle it.</p>
607      * 
608      * The object is not GZip-compressed before being encoded.
609      *
610      * @param serializableObject The object to encode
611      * @return The Base64-encoded object
612      * @throws java.io.IOException if there is an error
613      * @throws NullPointerException if serializedObject is null
614      * @since 1.4
615      */
616     public static String encodeObject( java.io.Serializable serializableObject )
617     throws java.io.IOException {
618         return encodeObject( serializableObject, NO_OPTIONS );
619     }   // end encodeObject
620     
621 
622 
623     /**
624      * Serializes an object and returns the Base64-encoded
625      * version of that serialized object.
626      *  
627      * <p>As of v 2.3, if the object
628      * cannot be serialized or there is another error,
629      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
630      * In earlier versions, it just returned a null value, but
631      * in retrospect that's a pretty poor way to handle it.</p>
632      * 
633      * The object is not GZip-compressed before being encoded.
634      * <p>
635      * Example options:<pre>
636      *   GZIP: gzip-compresses object before encoding it.
637      *   DO_BREAK_LINES: break lines at 76 characters
638      * </pre>
639      * <p>
640      * Example: <code>encodeObject( myObj, Base64.GZIP )</code> or
641      * <p>
642      * Example: <code>encodeObject( myObj, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
643      *
644      * @param serializableObject The object to encode
645      * @param options Specified options
646      * @return The Base64-encoded object
647      * @see Base64#GZIP
648      * @see Base64#DO_BREAK_LINES
649      * @throws java.io.IOException if there is an error
650      * @since 2.0
651      */
652     public static String encodeObject( java.io.Serializable serializableObject, int options )
653     throws java.io.IOException {
654 
655         if( serializableObject == null ){
656             throw new NullPointerException( "Cannot serialize a null object." );
657         }   // end if: null
658         
659         // Streams
660         java.io.ByteArrayOutputStream  baos  = null; 
661         java.io.OutputStream           b64os = null;
662         java.util.zip.GZIPOutputStream gzos  = null;
663         java.io.ObjectOutputStream     oos   = null;
664         
665         
666         try {
667             // ObjectOutputStream -> (GZIP) -> Base64 -> ByteArrayOutputStream
668             baos  = new java.io.ByteArrayOutputStream();
669             b64os = new Base64.OutputStream( baos, ENCODE | options );
670             if( (options & GZIP) != 0 ){
671                 // Gzip
672                 gzos = new java.util.zip.GZIPOutputStream(b64os);
673                 oos = new java.io.ObjectOutputStream( gzos );
674             } else {
675                 // Not gzipped
676                 oos = new java.io.ObjectOutputStream( b64os );
677             }
678             oos.writeObject( serializableObject );
679         }   // end try
680         catch( java.io.IOException e ) {
681             // Catch it and then throw it immediately so that
682             // the finally{} block is called for cleanup.
683             throw e;
684         }   // end catch
685         finally {
686             try{ oos.close();   } catch( Exception e ){}
687             try{ gzos.close();  } catch( Exception e ){}
688             try{ b64os.close(); } catch( Exception e ){}
689             try{ baos.close();  } catch( Exception e ){}
690         }   // end finally
691         
692         // Return value according to relevant encoding.
693         try {
694             return new String( baos.toByteArray(), PREFERRED_ENCODING );
695         }   // end try
696         catch (java.io.UnsupportedEncodingException uue){
697             // Fall back to some Java default
698             return new String( baos.toByteArray() );
699         }   // end catch
700         
701     }   // end encode
702     
703     
704 
705     /**
706      * Encodes a byte array into Base64 notation.
707      * Does not GZip-compress data.
708      *  
709      * @param source The data to convert
710      * @return The data in Base64-encoded form
711      * @throws NullPointerException if source array is null
712      * @since 1.4
713      */
714     public static String encodeBytes( byte[] source ) {
715         // Since we're not going to have the GZIP encoding turned on,
716         // we're not going to have an java.io.IOException thrown, so
717         // we should not force the user to have to catch it.
718         String encoded = null;
719         try {
720             encoded = encodeBytes(source, 0, source.length, NO_OPTIONS);
721         } catch (java.io.IOException ex) {
722             assert false : ex.getMessage();
723         }   // end catch
724         assert encoded != null;
725         return encoded;
726     }   // end encodeBytes
727     
728 
729 
730     /**
731      * Encodes a byte array into Base64 notation.
732      * <p>
733      * Example options:<pre>
734      *   GZIP: gzip-compresses object before encoding it.
735      *   DO_BREAK_LINES: break lines at 76 characters
736      *     <i>Note: Technically, this makes your encoding non-compliant.</i>
737      * </pre>
738      * <p>
739      * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
740      * <p>
741      * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
742      *
743      *  
744      * <p>As of v 2.3, if there is an error with the GZIP stream,
745      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
746      * In earlier versions, it just returned a null value, but
747      * in retrospect that's a pretty poor way to handle it.</p>
748      * 
749      *
750      * @param source The data to convert
751      * @param options Specified options
752      * @return The Base64-encoded data as a String
753      * @see Base64#GZIP
754      * @see Base64#DO_BREAK_LINES
755      * @throws java.io.IOException if there is an error
756      * @throws NullPointerException if source array is null
757      * @since 2.0
758      */
759     public static String encodeBytes( byte[] source, int options ) throws java.io.IOException {
760         return encodeBytes( source, 0, source.length, options );
761     }   // end encodeBytes
762     
763     
764     /**
765      * Encodes a byte array into Base64 notation.
766      * Does not GZip-compress data.
767      *  
768      * <p>As of v 2.3, if there is an error,
769      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
770      * In earlier versions, it just returned a null value, but
771      * in retrospect that's a pretty poor way to handle it.</p>
772      * 
773      *
774      * @param source The data to convert
775      * @param off Offset in array where conversion should begin
776      * @param len Length of data to convert
777      * @return The Base64-encoded data as a String
778      * @throws NullPointerException if source array is null
779      * @throws IllegalArgumentException if source array, offset, or length are invalid
780      * @since 1.4
781      */
782     public static String encodeBytes( byte[] source, int off, int len ) {
783         // Since we're not going to have the GZIP encoding turned on,
784         // we're not going to have an java.io.IOException thrown, so
785         // we should not force the user to have to catch it.
786         String encoded = null;
787         try {
788             encoded = encodeBytes( source, off, len, NO_OPTIONS );
789         } catch (java.io.IOException ex) {
790             assert false : ex.getMessage();
791         }   // end catch
792         assert encoded != null;
793         return encoded;
794     }   // end encodeBytes
795     
796     
797 
798     /**
799      * Encodes a byte array into Base64 notation.
800      * <p>
801      * Example options:<pre>
802      *   GZIP: gzip-compresses object before encoding it.
803      *   DO_BREAK_LINES: break lines at 76 characters
804      *     <i>Note: Technically, this makes your encoding non-compliant.</i>
805      * </pre>
806      * <p>
807      * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
808      * <p>
809      * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
810      *
811      *  
812      * <p>As of v 2.3, if there is an error with the GZIP stream,
813      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
814      * In earlier versions, it just returned a null value, but
815      * in retrospect that's a pretty poor way to handle it.</p>
816      * 
817      *
818      * @param source The data to convert
819      * @param off Offset in array where conversion should begin
820      * @param len Length of data to convert
821      * @param options Specified options
822      * @return The Base64-encoded data as a String
823      * @see Base64#GZIP
824      * @see Base64#DO_BREAK_LINES
825      * @throws java.io.IOException if there is an error
826      * @throws NullPointerException if source array is null
827      * @throws IllegalArgumentException if source array, offset, or length are invalid
828      * @since 2.0
829      */
830     public static String encodeBytes( byte[] source, int off, int len, int options ) throws java.io.IOException {
831         byte[] encoded = encodeBytesToBytes( source, off, len, options );
832 
833         // Return value according to relevant encoding.
834         try {
835             return new String( encoded, PREFERRED_ENCODING );
836         }   // end try
837         catch (java.io.UnsupportedEncodingException uue) {
838             return new String( encoded );
839         }   // end catch
840         
841     }   // end encodeBytes
842 
843 
844 
845 
846     /**
847      * Similar to {@link #encodeBytes(byte[])} but returns
848      * a byte array instead of instantiating a String. This is more efficient
849      * if you're working with I/O streams and have large data sets to encode.
850      *
851      *
852      * @param source The data to convert
853      * @return The Base64-encoded data as a byte[] (of ASCII characters)
854      * @throws NullPointerException if source array is null
855      * @since 2.3.1
856      */
857     public static byte[] encodeBytesToBytes( byte[] source ) {
858         byte[] encoded = null;
859         try {
860             encoded = encodeBytesToBytes( source, 0, source.length, Base64.NO_OPTIONS );
861         } catch( java.io.IOException ex ) {
862             assert false : "IOExceptions only come from GZipping, which is turned off: " + ex.getMessage();
863         }
864         return encoded;
865     }
866 
867 
868     /**
869      * Similar to {@link #encodeBytes(byte[], int, int, int)} but returns
870      * a byte array instead of instantiating a String. This is more efficient
871      * if you're working with I/O streams and have large data sets to encode.
872      *
873      *
874      * @param source The data to convert
875      * @param off Offset in array where conversion should begin
876      * @param len Length of data to convert
877      * @param options Specified options
878      * @return The Base64-encoded data as a String
879      * @see Base64#GZIP
880      * @see Base64#DO_BREAK_LINES
881      * @throws java.io.IOException if there is an error
882      * @throws NullPointerException if source array is null
883      * @throws IllegalArgumentException if source array, offset, or length are invalid
884      * @since 2.3.1
885      */
886     public static byte[] encodeBytesToBytes( byte[] source, int off, int len, int options ) throws java.io.IOException {
887 
888         if( source == null ){
889             throw new NullPointerException( "Cannot serialize a null array." );
890         }   // end if: null
891 
892         if( off < 0 ){
893             throw new IllegalArgumentException( "Cannot have negative offset: " + off );
894         }   // end if: off < 0
895 
896         if( len < 0 ){
897             throw new IllegalArgumentException( "Cannot have length offset: " + len );
898         }   // end if: len < 0
899 
900         if( off + len > source.length  ){
901             throw new IllegalArgumentException(
902             String.format( "Cannot have offset of %d and length of %d with array of length %d", off,len,source.length));
903         }   // end if: off < 0
904 
905 
906 
907         // Compress?
908         if( (options & GZIP) != 0 ) {
909             java.io.ByteArrayOutputStream  baos  = null;
910             java.util.zip.GZIPOutputStream gzos  = null;
911             Base64.OutputStream            b64os = null;
912 
913             try {
914                 // GZip -> Base64 -> ByteArray
915                 baos = new java.io.ByteArrayOutputStream();
916                 b64os = new Base64.OutputStream( baos, ENCODE | options );
917                 gzos  = new java.util.zip.GZIPOutputStream( b64os );
918 
919                 gzos.write( source, off, len );
920                 gzos.close();
921             }   // end try
922             catch( java.io.IOException e ) {
923                 // Catch it and then throw it immediately so that
924                 // the finally{} block is called for cleanup.
925                 throw e;
926             }   // end catch
927             finally {
928                 try{ gzos.close();  } catch( Exception e ){}
929                 try{ b64os.close(); } catch( Exception e ){}
930                 try{ baos.close();  } catch( Exception e ){}
931             }   // end finally
932 
933             return baos.toByteArray();
934         }   // end if: compress
935 
936         // Else, don't compress. Better not to use streams at all then.
937         else {
938             boolean breakLines = (options & DO_BREAK_LINES) != 0;
939 
940             //int    len43   = len * 4 / 3;
941             //byte[] outBuff = new byte[   ( len43 )                      // Main 4:3
942             //                           + ( (len % 3) > 0 ? 4 : 0 )      // Account for padding
943             //                           + (breakLines ? ( len43 / MAX_LINE_LENGTH ) : 0) ]; // New lines
944             // Try to determine more precisely how big the array needs to be.
945             // If we get it right, we don't have to do an array copy, and
946             // we save a bunch of memory.
947             int encLen = ( len / 3 ) * 4 + ( len % 3 > 0 ? 4 : 0 ); // Bytes needed for actual encoding
948             if( breakLines ){
949                 encLen += encLen / MAX_LINE_LENGTH; // Plus extra newline characters
950             }
951             byte[] outBuff = new byte[ encLen ];
952 
953 
954             int d = 0;
955             int e = 0;
956             int len2 = len - 2;
957             int lineLength = 0;
958             for( ; d < len2; d+=3, e+=4 ) {
959                 encode3to4( source, d+off, 3, outBuff, e, options );
960 
961                 lineLength += 4;
962                 if( breakLines && lineLength >= MAX_LINE_LENGTH )
963                 {
964                     outBuff[e+4] = NEW_LINE;
965                     e++;
966                     lineLength = 0;
967                 }   // end if: end of line
968             }   // en dfor: each piece of array
969 
970             if( d < len ) {
971                 encode3to4( source, d+off, len - d, outBuff, e, options );
972                 e += 4;
973             }   // end if: some padding needed
974 
975 
976             // Only resize array if we didn't guess it right.
977             if( e <= outBuff.length - 1 ){
978                 // If breaking lines and the last byte falls right at
979                 // the line length (76 bytes per line), there will be
980                 // one extra byte, and the array will need to be resized.
981                 // Not too bad of an estimate on array size, I'd say.
982                 byte[] finalOut = new byte[e];
983                 System.arraycopy(outBuff,0, finalOut,0,e);
984                 //System.err.println("Having to resize array from " + outBuff.length + " to " + e );
985                 return finalOut;
986             } else {
987                 //System.err.println("No need to resize array.");
988                 return outBuff;
989             }
990         
991         }   // end else: don't compress
992 
993     }   // end encodeBytesToBytes
994     
995 
996     
997     
998     
999 /* ********  D E C O D I N G   M E T H O D S  ******** */
1000     
1001     
1002     /**
1003      * Decodes four bytes from array <var>source</var>
1004      * and writes the resulting bytes (up to three of them)
1005      * to <var>destination</var>.
1006      * The source and destination arrays can be manipulated
1007      * anywhere along their length by specifying 
1008      * <var>srcOffset</var> and <var>destOffset</var>.
1009      * This method does not check to make sure your arrays
1010      * are large enough to accomodate <var>srcOffset</var> + 4 for
1011      * the <var>source</var> array or <var>destOffset</var> + 3 for
1012      * the <var>destination</var> array.
1013      * This method returns the actual number of bytes that 
1014      * were converted from the Base64 encoding.
1015 	 * <p>This is the lowest level of the decoding methods with
1016 	 * all possible parameters.</p>
1017      * 
1018      *
1019      * @param source the array to convert
1020      * @param srcOffset the index where conversion begins
1021      * @param destination the array to hold the conversion
1022      * @param destOffset the index where output will be put
1023 	 * @param options alphabet type is pulled from this (standard, url-safe, ordered)
1024      * @return the number of decoded bytes converted
1025      * @throws NullPointerException if source or destination arrays are null
1026      * @throws IllegalArgumentException if srcOffset or destOffset are invalid
1027      *         or there is not enough room in the array.
1028      * @since 1.3
1029      */
1030     private static int decode4to3( 
1031     byte[] source, int srcOffset, 
1032     byte[] destination, int destOffset, int options ) {
1033         
1034         // Lots of error checking and exception throwing
1035         if( source == null ){
1036             throw new NullPointerException( "Source array was null." );
1037         }   // end if
1038         if( destination == null ){
1039             throw new NullPointerException( "Destination array was null." );
1040         }   // end if
1041         if( srcOffset < 0 || srcOffset + 3 >= source.length ){
1042             throw new IllegalArgumentException( String.format(
1043             "Source array with length %d cannot have offset of %d and still process four bytes.", source.length, srcOffset ) );
1044         }   // end if
1045         if( destOffset < 0 || destOffset +2 >= destination.length ){
1046             throw new IllegalArgumentException( String.format(
1047             "Destination array with length %d cannot have offset of %d and still store three bytes.", destination.length, destOffset ) );
1048         }   // end if
1049         
1050         
1051         byte[] DECODABET = getDecodabet( options ); 
1052 	
1053         // Example: Dk==
1054         if( source[ srcOffset + 2] == EQUALS_SIGN ) {
1055             // Two ways to do the same thing. Don't know which way I like best.
1056           //int outBuff =   ( ( DECODABET[ source[ srcOffset    ] ] << 24 ) >>>  6 )
1057           //              | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
1058             int outBuff =   ( ( DECODABET[ source[ srcOffset    ] ] & 0xFF ) << 18 )
1059                           | ( ( DECODABET[ source[ srcOffset + 1] ] & 0xFF ) << 12 );
1060             
1061             destination[ destOffset ] = (byte)( outBuff >>> 16 );
1062             return 1;
1063         }
1064         
1065         // Example: DkL=
1066         else if( source[ srcOffset + 3 ] == EQUALS_SIGN ) {
1067             // Two ways to do the same thing. Don't know which way I like best.
1068           //int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] << 24 ) >>>  6 )
1069           //              | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
1070           //              | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
1071             int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] & 0xFF ) << 18 )
1072                           | ( ( DECODABET[ source[ srcOffset + 1 ] ] & 0xFF ) << 12 )
1073                           | ( ( DECODABET[ source[ srcOffset + 2 ] ] & 0xFF ) <<  6 );
1074             
1075             destination[ destOffset     ] = (byte)( outBuff >>> 16 );
1076             destination[ destOffset + 1 ] = (byte)( outBuff >>>  8 );
1077             return 2;
1078         }
1079         
1080         // Example: DkLE
1081         else {
1082             // Two ways to do the same thing. Don't know which way I like best.
1083           //int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] << 24 ) >>>  6 )
1084           //              | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
1085           //              | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
1086           //              | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
1087             int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] & 0xFF ) << 18 )
1088                           | ( ( DECODABET[ source[ srcOffset + 1 ] ] & 0xFF ) << 12 )
1089                           | ( ( DECODABET[ source[ srcOffset + 2 ] ] & 0xFF ) <<  6)
1090                           | ( ( DECODABET[ source[ srcOffset + 3 ] ] & 0xFF )      );
1091 
1092             
1093             destination[ destOffset     ] = (byte)( outBuff >> 16 );
1094             destination[ destOffset + 1 ] = (byte)( outBuff >>  8 );
1095             destination[ destOffset + 2 ] = (byte)( outBuff       );
1096 
1097             return 3;
1098         }
1099     }   // end decodeToBytes
1100     
1101 
1102 
1103 
1104 
1105     /**
1106      * Low-level access to decoding ASCII characters in
1107      * the form of a byte array. <strong>Ignores GUNZIP option, if
1108      * it's set.</strong> This is not generally a recommended method,
1109      * although it is used internally as part of the decoding process.
1110      * Special case: if len = 0, an empty array is returned. Still,
1111      * if you need more speed and reduced memory footprint (and aren't
1112      * gzipping), consider this method.
1113      *
1114      * @param source The Base64 encoded data
1115      * @return decoded data
1116      * @since 2.3.1
1117      */
1118     public static byte[] decode( byte[] source )
1119     throws java.io.IOException {
1120         byte[] decoded = null;
1121 //        try {
1122             decoded = decode( source, 0, source.length, Base64.NO_OPTIONS );
1123 //        } catch( java.io.IOException ex ) {
1124 //            assert false : "IOExceptions only come from GZipping, which is turned off: " + ex.getMessage();
1125 //        }
1126         return decoded;
1127     }
1128 
1129     
1130     
1131     /**
1132      * Low-level access to decoding ASCII characters in
1133      * the form of a byte array. <strong>Ignores GUNZIP option, if
1134      * it's set.</strong> This is not generally a recommended method,
1135      * although it is used internally as part of the decoding process.
1136      * Special case: if len = 0, an empty array is returned. Still,
1137      * if you need more speed and reduced memory footprint (and aren't
1138      * gzipping), consider this method.
1139      *
1140      * @param source The Base64 encoded data
1141      * @param off    The offset of where to begin decoding
1142      * @param len    The length of characters to decode
1143      * @param options Can specify options such as alphabet type to use
1144      * @return decoded data
1145      * @throws java.io.IOException If bogus characters exist in source data
1146      * @since 1.3
1147      */
1148     public static byte[] decode( byte[] source, int off, int len, int options )
1149     throws java.io.IOException {
1150         
1151         // Lots of error checking and exception throwing
1152         if( source == null ){
1153             throw new NullPointerException( "Cannot decode null source array." );
1154         }   // end if
1155         if( off < 0 || off + len > source.length ){
1156             throw new IllegalArgumentException( String.format(
1157             "Source array with length %d cannot have offset of %d and process %d bytes.", source.length, off, len ) );
1158         }   // end if
1159         
1160         if( len == 0 ){
1161             return new byte[0];
1162         }else if( len < 4 ){
1163             throw new IllegalArgumentException( 
1164             "Base64-encoded string must have at least four characters, but length specified was " + len );
1165         }   // end if
1166         
1167         byte[] DECODABET = getDecodabet( options );
1168 	
1169         int    len34   = len * 3 / 4;       // Estimate on array size
1170         byte[] outBuff = new byte[ len34 ]; // Upper limit on size of output
1171         int    outBuffPosn = 0;             // Keep track of where we're writing
1172         
1173         byte[] b4        = new byte[4];     // Four byte buffer from source, eliminating white space
1174         int    b4Posn    = 0;               // Keep track of four byte input buffer
1175         int    i         = 0;               // Source array counter
1176         byte   sbiDecode = 0;               // Special value from DECODABET
1177         
1178         for( i = off; i < off+len; i++ ) {  // Loop through source
1179             
1180             sbiDecode = DECODABET[ source[i]&0xFF ];
1181             
1182             // White space, Equals sign, or legit Base64 character
1183             // Note the values such as -5 and -9 in the
1184             // DECODABETs at the top of the file.
1185             if( sbiDecode >= WHITE_SPACE_ENC )  {
1186                 if( sbiDecode >= EQUALS_SIGN_ENC ) {
1187                     b4[ b4Posn++ ] = source[i];         // Save non-whitespace
1188                     if( b4Posn > 3 ) {                  // Time to decode?
1189                         outBuffPosn += decode4to3( b4, 0, outBuff, outBuffPosn, options );
1190                         b4Posn = 0;
1191                         
1192                         // If that was the equals sign, break out of 'for' loop
1193                         if( source[i] == EQUALS_SIGN ) {
1194                             break;
1195                         }   // end if: equals sign
1196                     }   // end if: quartet built
1197                 }   // end if: equals sign or better
1198             }   // end if: white space, equals sign or better
1199             else {
1200                 // There's a bad input character in the Base64 stream.
1201                 throw new java.io.IOException( String.format(
1202                 "Bad Base64 input character decimal %d in array position %d", ((int)source[i])&0xFF, i ) );
1203             }   // end else: 
1204         }   // each input character
1205                                    
1206         byte[] out = new byte[ outBuffPosn ];
1207         System.arraycopy( outBuff, 0, out, 0, outBuffPosn ); 
1208         return out;
1209     }   // end decode
1210     
1211     
1212 	
1213 	
1214     /**
1215      * Decodes data from Base64 notation, automatically
1216      * detecting gzip-compressed data and decompressing it.
1217      *
1218      * @param s the string to decode
1219      * @return the decoded data
1220      * @throws java.io.IOException If there is a problem
1221      * @since 1.4
1222      */
1223     public static byte[] decode( String s ) throws java.io.IOException {
1224         return decode( s, NO_OPTIONS );
1225     }
1226 
1227     
1228     
1229     /**
1230      * Decodes data from Base64 notation, automatically
1231      * detecting gzip-compressed data and decompressing it.
1232      *
1233      * @param s the string to decode
1234      * @param options encode options such as URL_SAFE
1235      * @return the decoded data
1236      * @throws java.io.IOException if there is an error
1237      * @throws NullPointerException if <tt>s</tt> is null
1238      * @since 1.4
1239      */
1240     public static byte[] decode( String s, int options ) throws java.io.IOException {
1241         
1242         if( s == null ){
1243             throw new NullPointerException( "Input string was null." );
1244         }   // end if
1245         
1246         byte[] bytes;
1247         try {
1248             bytes = s.getBytes( PREFERRED_ENCODING );
1249         }   // end try
1250         catch( java.io.UnsupportedEncodingException uee ) {
1251             bytes = s.getBytes();
1252         }   // end catch
1253 		//</change>
1254         
1255         // Decode
1256         bytes = decode( bytes, 0, bytes.length, options );
1257         
1258         // Check to see if it's gzip-compressed
1259         // GZIP Magic Two-Byte Number: 0x8b1f (35615)
1260         boolean dontGunzip = (options & DONT_GUNZIP) != 0;
1261         if( (bytes != null) && (bytes.length >= 4) && (!dontGunzip) ) {
1262             
1263             int head = ((int)bytes[0] & 0xff) | ((bytes[1] << 8) & 0xff00);
1264             if( java.util.zip.GZIPInputStream.GZIP_MAGIC == head )  {
1265                 java.io.ByteArrayInputStream  bais = null;
1266                 java.util.zip.GZIPInputStream gzis = null;
1267                 java.io.ByteArrayOutputStream baos = null;
1268                 byte[] buffer = new byte[2048];
1269                 int    length = 0;
1270 
1271                 try {
1272                     baos = new java.io.ByteArrayOutputStream();
1273                     bais = new java.io.ByteArrayInputStream( bytes );
1274                     gzis = new java.util.zip.GZIPInputStream( bais );
1275 
1276                     while( ( length = gzis.read( buffer ) ) >= 0 ) {
1277                         baos.write(buffer,0,length);
1278                     }   // end while: reading input
1279 
1280                     // No error? Get new bytes.
1281                     bytes = baos.toByteArray();
1282 
1283                 }   // end try
1284                 catch( java.io.IOException e ) {
1285                     e.printStackTrace();
1286                     // Just return originally-decoded bytes
1287                 }   // end catch
1288                 finally {
1289                     try{ baos.close(); } catch( Exception e ){}
1290                     try{ gzis.close(); } catch( Exception e ){}
1291                     try{ bais.close(); } catch( Exception e ){}
1292                 }   // end finally
1293 
1294             }   // end if: gzipped
1295         }   // end if: bytes.length >= 2
1296         
1297         return bytes;
1298     }   // end decode
1299 
1300 
1301 
1302     /**
1303      * Attempts to decode Base64 data and deserialize a Java
1304      * Object within. Returns <tt>null</tt> if there was an error.
1305      *
1306      * @param encodedObject The Base64 data to decode
1307      * @return The decoded and deserialized object
1308      * @throws NullPointerException if encodedObject is null
1309      * @throws java.io.IOException if there is a general error
1310      * @throws ClassNotFoundException if the decoded object is of a
1311      *         class that cannot be found by the JVM
1312      * @since 1.5
1313      */
1314     public static Object decodeToObject( String encodedObject )
1315     throws java.io.IOException, java.lang.ClassNotFoundException {
1316         return decodeToObject(encodedObject,NO_OPTIONS,null);
1317     }
1318     
1319 
1320     /**
1321      * Attempts to decode Base64 data and deserialize a Java
1322      * Object within. Returns <tt>null</tt> if there was an error.
1323      * If <tt>loader</tt> is not null, it will be the class loader
1324      * used when deserializing.
1325      *
1326      * @param encodedObject The Base64 data to decode
1327      * @param options Various parameters related to decoding
1328      * @param loader Optional class loader to use in deserializing classes.
1329      * @return The decoded and deserialized object
1330      * @throws NullPointerException if encodedObject is null
1331      * @throws java.io.IOException if there is a general error
1332      * @throws ClassNotFoundException if the decoded object is of a 
1333      *         class that cannot be found by the JVM
1334      * @since 2.3.4
1335      */
1336     public static Object decodeToObject( 
1337     String encodedObject, int options, final ClassLoader loader )
1338     throws java.io.IOException, java.lang.ClassNotFoundException {
1339         
1340         // Decode and gunzip if necessary
1341         byte[] objBytes = decode( encodedObject, options );
1342         
1343         java.io.ByteArrayInputStream  bais = null;
1344         java.io.ObjectInputStream     ois  = null;
1345         Object obj = null;
1346         
1347         try {
1348             bais = new java.io.ByteArrayInputStream( objBytes );
1349 
1350             // If no custom class loader is provided, use Java's builtin OIS.
1351             if( loader == null ){
1352                 ois  = new java.io.ObjectInputStream( bais );
1353             }   // end if: no loader provided
1354 
1355             // Else make a customized object input stream that uses
1356             // the provided class loader.
1357             else {
1358                 ois = new java.io.ObjectInputStream(bais){
1359                     @Override
1360                     public Class<?> resolveClass(java.io.ObjectStreamClass streamClass)
1361                     throws java.io.IOException, ClassNotFoundException {
1362                         Class c = Class.forName(streamClass.getName(), false, loader);
1363                         if( c == null ){
1364                             return super.resolveClass(streamClass);
1365                         } else {
1366                             return c;   // Class loader knows of this class.
1367                         }   // end else: not null
1368                     }   // end resolveClass
1369                 };  // end ois
1370             }   // end else: no custom class loader
1371         
1372             obj = ois.readObject();
1373         }   // end try
1374         catch( java.io.IOException e ) {
1375             throw e;    // Catch and throw in order to execute finally{}
1376         }   // end catch
1377         catch( java.lang.ClassNotFoundException e ) {
1378             throw e;    // Catch and throw in order to execute finally{}
1379         }   // end catch
1380         finally {
1381             try{ bais.close(); } catch( Exception e ){}
1382             try{ ois.close();  } catch( Exception e ){}
1383         }   // end finally
1384         
1385         return obj;
1386     }   // end decodeObject
1387     
1388     
1389     
1390     /**
1391      * Convenience method for encoding data to a file.
1392      *
1393      * <p>As of v 2.3, if there is a error,
1394      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
1395      * In earlier versions, it just returned false, but
1396      * in retrospect that's a pretty poor way to handle it.</p>
1397      * 
1398      * @param dataToEncode byte array of data to encode in base64 form
1399      * @param filename Filename for saving encoded data
1400      * @throws java.io.IOException if there is an error
1401      * @throws NullPointerException if dataToEncode is null
1402      * @since 2.1
1403      */
1404     public static void encodeToFile( byte[] dataToEncode, String filename )
1405     throws java.io.IOException {
1406         
1407         if( dataToEncode == null ){
1408             throw new NullPointerException( "Data to encode was null." );
1409         }   // end iff
1410         
1411         Base64.OutputStream bos = null;
1412         try {
1413             bos = new Base64.OutputStream( 
1414                   new java.io.FileOutputStream( filename ), Base64.ENCODE );
1415             bos.write( dataToEncode );
1416         }   // end try
1417         catch( java.io.IOException e ) {
1418             throw e; // Catch and throw to execute finally{} block
1419         }   // end catch: java.io.IOException
1420         finally {
1421             try{ bos.close(); } catch( Exception e ){}
1422         }   // end finally
1423         
1424     }   // end encodeToFile
1425     
1426     
1427     /**
1428      * Convenience method for decoding data to a file.
1429      *
1430      * <p>As of v 2.3, if there is a error,
1431      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
1432      * In earlier versions, it just returned false, but
1433      * in retrospect that's a pretty poor way to handle it.</p>
1434      * 
1435      * @param dataToDecode Base64-encoded data as a string
1436      * @param filename Filename for saving decoded data
1437      * @throws java.io.IOException if there is an error
1438      * @since 2.1
1439      */
1440     public static void decodeToFile( String dataToDecode, String filename )
1441     throws java.io.IOException {
1442         
1443         Base64.OutputStream bos = null;
1444         try{
1445             bos = new Base64.OutputStream( 
1446                       new java.io.FileOutputStream( filename ), Base64.DECODE );
1447             bos.write( dataToDecode.getBytes( PREFERRED_ENCODING ) );
1448         }   // end try
1449         catch( java.io.IOException e ) {
1450             throw e; // Catch and throw to execute finally{} block
1451         }   // end catch: java.io.IOException
1452         finally {
1453                 try{ bos.close(); } catch( Exception e ){}
1454         }   // end finally
1455         
1456     }   // end decodeToFile
1457     
1458     
1459     
1460     
1461     /**
1462      * Convenience method for reading a base64-encoded
1463      * file and decoding it.
1464      *
1465      * <p>As of v 2.3, if there is a error,
1466      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
1467      * In earlier versions, it just returned false, but
1468      * in retrospect that's a pretty poor way to handle it.</p>
1469      * 
1470      * @param filename Filename for reading encoded data
1471      * @return decoded byte array
1472      * @throws java.io.IOException if there is an error
1473      * @since 2.1
1474      */
1475     public static byte[] decodeFromFile( String filename )
1476     throws java.io.IOException {
1477         
1478         byte[] decodedData = null;
1479         Base64.InputStream bis = null;
1480         try
1481         {
1482             // Set up some useful variables
1483             java.io.File file = new java.io.File( filename );
1484             byte[] buffer = null;
1485             int length   = 0;
1486             int numBytes = 0;
1487             
1488             // Check for size of file
1489             if( file.length() > Integer.MAX_VALUE )
1490             {
1491                 throw new java.io.IOException( "File is too big for this convenience method (" + file.length() + " bytes)." );
1492             }   // end if: file too big for int index
1493             buffer = new byte[ (int)file.length() ];
1494             
1495             // Open a stream
1496             bis = new Base64.InputStream( 
1497                       new java.io.BufferedInputStream( 
1498                       new java.io.FileInputStream( file ) ), Base64.DECODE );
1499             
1500             // Read until done
1501             while( ( numBytes = bis.read( buffer, length, 4096 ) ) >= 0 ) {
1502                 length += numBytes;
1503             }   // end while
1504             
1505             // Save in a variable to return
1506             decodedData = new byte[ length ];
1507             System.arraycopy( buffer, 0, decodedData, 0, length );
1508             
1509         }   // end try
1510         catch( java.io.IOException e ) {
1511             throw e; // Catch and release to execute finally{}
1512         }   // end catch: java.io.IOException
1513         finally {
1514             try{ bis.close(); } catch( Exception e) {}
1515         }   // end finally
1516         
1517         return decodedData;
1518     }   // end decodeFromFile
1519     
1520     
1521     
1522     /**
1523      * Convenience method for reading a binary file
1524      * and base64-encoding it.
1525      *
1526      * <p>As of v 2.3, if there is a error,
1527      * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
1528      * In earlier versions, it just returned false, but
1529      * in retrospect that's a pretty poor way to handle it.</p>
1530      * 
1531      * @param filename Filename for reading binary data
1532      * @return base64-encoded string
1533      * @throws java.io.IOException if there is an error
1534      * @since 2.1
1535      */
1536     public static String encodeFromFile( String filename )
1537     throws java.io.IOException {
1538         
1539         String encodedData = null;
1540         Base64.InputStream bis = null;
1541         try
1542         {
1543             // Set up some useful variables
1544             java.io.File file = new java.io.File( filename );
1545             byte[] buffer = new byte[ Math.max((int)(file.length() * 1.4+1),40) ]; // Need max() for math on small files (v2.2.1); Need +1 for a few corner cases (v2.3.5)
1546             int length   = 0;
1547             int numBytes = 0;
1548             
1549             // Open a stream
1550             bis = new Base64.InputStream( 
1551                       new java.io.BufferedInputStream( 
1552                       new java.io.FileInputStream( file ) ), Base64.ENCODE );
1553             
1554             // Read until done
1555             while( ( numBytes = bis.read( buffer, length, 4096 ) ) >= 0 ) {
1556                 length += numBytes;
1557             }   // end while
1558             
1559             // Save in a variable to return
1560             encodedData = new String( buffer, 0, length, Base64.PREFERRED_ENCODING );
1561                 
1562         }   // end try
1563         catch( java.io.IOException e ) {
1564             throw e; // Catch and release to execute finally{}
1565         }   // end catch: java.io.IOException
1566         finally {
1567             try{ bis.close(); } catch( Exception e) {}
1568         }   // end finally
1569         
1570         return encodedData;
1571         }   // end encodeFromFile
1572     
1573     /**
1574      * Reads <tt>infile</tt> and encodes it to <tt>outfile</tt>.
1575      *
1576      * @param infile Input file
1577      * @param outfile Output file
1578      * @throws java.io.IOException if there is an error
1579      * @since 2.2
1580      */
1581     public static void encodeFileToFile( String infile, String outfile )
1582     throws java.io.IOException {
1583         
1584         String encoded = Base64.encodeFromFile( infile );
1585         java.io.OutputStream out = null;
1586         try{
1587             out = new java.io.BufferedOutputStream(
1588                   new java.io.FileOutputStream( outfile ) );
1589             out.write( encoded.getBytes("US-ASCII") ); // Strict, 7-bit output.
1590         }   // end try
1591         catch( java.io.IOException e ) {
1592             throw e; // Catch and release to execute finally{}
1593         }   // end catch
1594         finally {
1595             try { out.close(); }
1596             catch( Exception ex ){}
1597         }   // end finally    
1598     }   // end encodeFileToFile
1599 
1600 
1601     /**
1602      * Reads <tt>infile</tt> and decodes it to <tt>outfile</tt>.
1603      *
1604      * @param infile Input file
1605      * @param outfile Output file
1606      * @throws java.io.IOException if there is an error
1607      * @since 2.2
1608      */
1609     public static void decodeFileToFile( String infile, String outfile )
1610     throws java.io.IOException {
1611         
1612         byte[] decoded = Base64.decodeFromFile( infile );
1613         java.io.OutputStream out = null;
1614         try{
1615             out = new java.io.BufferedOutputStream(
1616                   new java.io.FileOutputStream( outfile ) );
1617             out.write( decoded );
1618         }   // end try
1619         catch( java.io.IOException e ) {
1620             throw e; // Catch and release to execute finally{}
1621         }   // end catch
1622         finally {
1623             try { out.close(); }
1624             catch( Exception ex ){}
1625         }   // end finally    
1626     }   // end decodeFileToFile
1627     
1628     
1629     /* ********  I N N E R   C L A S S   I N P U T S T R E A M  ******** */
1630     
1631     
1632     
1633     /**
1634      * A {@link Base64.InputStream} will read data from another
1635      * <tt>java.io.InputStream</tt>, given in the constructor,
1636      * and encode/decode to/from Base64 notation on the fly.
1637      *
1638      * @see Base64
1639      * @since 1.3
1640      */
1641     public static class InputStream extends java.io.FilterInputStream {
1642         
1643         private boolean encode;         // Encoding or decoding
1644         private int     position;       // Current position in the buffer
1645         private byte[]  buffer;         // Small buffer holding converted data
1646         private int     bufferLength;   // Length of buffer (3 or 4)
1647         private int     numSigBytes;    // Number of meaningful bytes in the buffer
1648         private int     lineLength;
1649         private boolean breakLines;     // Break lines at less than 80 characters
1650         private int     options;        // Record options used to create the stream.
1651         private byte[]  decodabet;      // Local copies to avoid extra method calls
1652         
1653         
1654         /**
1655          * Constructs a {@link Base64.InputStream} in DECODE mode.
1656          *
1657          * @param in the <tt>java.io.InputStream</tt> from which to read data.
1658          * @since 1.3
1659          */
1660         public InputStream( java.io.InputStream in ) {
1661             this( in, DECODE );
1662         }   // end constructor
1663         
1664         
1665         /**
1666          * Constructs a {@link Base64.InputStream} in
1667          * either ENCODE or DECODE mode.
1668          * <p>
1669          * Valid options:<pre>
1670          *   ENCODE or DECODE: Encode or Decode as data is read.
1671          *   DO_BREAK_LINES: break lines at 76 characters
1672          *     (only meaningful when encoding)</i>
1673          * </pre>
1674          * <p>
1675          * Example: <code>new Base64.InputStream( in, Base64.DECODE )</code>
1676          *
1677          *
1678          * @param in the <tt>java.io.InputStream</tt> from which to read data.
1679          * @param options Specified options
1680          * @see Base64#ENCODE
1681          * @see Base64#DECODE
1682          * @see Base64#DO_BREAK_LINES
1683          * @since 2.0
1684          */
1685         public InputStream( java.io.InputStream in, int options ) {
1686             
1687             super( in );
1688             this.options      = options; // Record for later
1689             this.breakLines   = (options & DO_BREAK_LINES) > 0;
1690             this.encode       = (options & ENCODE) > 0;
1691             this.bufferLength = encode ? 4 : 3;
1692             this.buffer       = new byte[ bufferLength ];
1693             this.position     = -1;
1694             this.lineLength   = 0;
1695             this.decodabet    = getDecodabet(options);
1696         }   // end constructor
1697         
1698         /**
1699          * Reads enough of the input stream to convert
1700          * to/from Base64 and returns the next byte.
1701          *
1702          * @return next byte
1703          * @since 1.3
1704          */
1705         @Override
1706         public int read() throws java.io.IOException  {
1707             
1708             // Do we need to get data?
1709             if( position < 0 ) {
1710                 if( encode ) {
1711                     byte[] b3 = new byte[3];
1712                     int numBinaryBytes = 0;
1713                     for( int i = 0; i < 3; i++ ) {
1714                         int b = in.read();
1715 
1716                         // If end of stream, b is -1.
1717                         if( b >= 0 ) {
1718                             b3[i] = (byte)b;
1719                             numBinaryBytes++;
1720                         } else {
1721                             break; // out of for loop
1722                         }   // end else: end of stream
1723                             
1724                     }   // end for: each needed input byte
1725                     
1726                     if( numBinaryBytes > 0 ) {
1727                         encode3to4( b3, 0, numBinaryBytes, buffer, 0, options );
1728                         position = 0;
1729                         numSigBytes = 4;
1730                     }   // end if: got data
1731                     else {
1732                         return -1;  // Must be end of stream
1733                     }   // end else
1734                 }   // end if: encoding
1735                 
1736                 // Else decoding
1737                 else {
1738                     byte[] b4 = new byte[4];
1739                     int i = 0;
1740                     for( i = 0; i < 4; i++ ) {
1741                         // Read four "meaningful" bytes:
1742                         int b = 0;
1743                         do{ b = in.read(); }
1744                         while( b >= 0 && decodabet[ b & 0x7f ] <= WHITE_SPACE_ENC );
1745                         
1746                         if( b < 0 ) {
1747                             break; // Reads a -1 if end of stream
1748                         }   // end if: end of stream
1749                         
1750                         b4[i] = (byte)b;
1751                     }   // end for: each needed input byte
1752                     
1753                     if( i == 4 ) {
1754                         numSigBytes = decode4to3( b4, 0, buffer, 0, options );
1755                         position = 0;
1756                     }   // end if: got four characters
1757                     else if( i == 0 ){
1758                         return -1;
1759                     }   // end else if: also padded correctly
1760                     else {
1761                         // Must have broken out from above.
1762                         throw new java.io.IOException( "Improperly padded Base64 input." );
1763                     }   // end 
1764                     
1765                 }   // end else: decode
1766             }   // end else: get data
1767             
1768             // Got data?
1769             if( position >= 0 ) {
1770                 // End of relevant data?
1771                 if( /*!encode &&*/ position >= numSigBytes ){
1772                     return -1;
1773                 }   // end if: got data
1774                 
1775                 if( encode && breakLines && lineLength >= MAX_LINE_LENGTH ) {
1776                     lineLength = 0;
1777                     return '\n';
1778                 }   // end if
1779                 else {
1780                     lineLength++;   // This isn't important when decoding
1781                                     // but throwing an extra "if" seems
1782                                     // just as wasteful.
1783                     
1784                     int b = buffer[ position++ ];
1785 
1786                     if( position >= bufferLength ) {
1787                         position = -1;
1788                     }   // end if: end
1789 
1790                     return b & 0xFF; // This is how you "cast" a byte that's
1791                                      // intended to be unsigned.
1792                 }   // end else
1793             }   // end if: position >= 0
1794             
1795             // Else error
1796             else {
1797                 throw new java.io.IOException( "Error in Base64 code reading stream." );
1798             }   // end else
1799         }   // end read
1800         
1801         
1802         /**
1803          * Calls {@link #read()} repeatedly until the end of stream
1804          * is reached or <var>len</var> bytes are read.
1805          * Returns number of bytes read into array or -1 if
1806          * end of stream is encountered.
1807          *
1808          * @param dest array to hold values
1809          * @param off offset for array
1810          * @param len max number of bytes to read into array
1811          * @return bytes read into array or -1 if end of stream is encountered.
1812          * @since 1.3
1813          */
1814         @Override
1815         public int read( byte[] dest, int off, int len ) 
1816         throws java.io.IOException {
1817             int i;
1818             int b;
1819             for( i = 0; i < len; i++ ) {
1820                 b = read();
1821                 
1822                 if( b >= 0 ) {
1823                     dest[off + i] = (byte) b;
1824                 }
1825                 else if( i == 0 ) {
1826                     return -1;
1827                 }
1828                 else {
1829                     break; // Out of 'for' loop
1830                 } // Out of 'for' loop
1831             }   // end for: each byte read
1832             return i;
1833         }   // end read
1834         
1835     }   // end inner class InputStream
1836     
1837     
1838     
1839     
1840     
1841     
1842     /* ********  I N N E R   C L A S S   O U T P U T S T R E A M  ******** */
1843     
1844     
1845     
1846     /**
1847      * A {@link Base64.OutputStream} will write data to another
1848      * <tt>java.io.OutputStream</tt>, given in the constructor,
1849      * and encode/decode to/from Base64 notation on the fly.
1850      *
1851      * @see Base64
1852      * @since 1.3
1853      */
1854     public static class OutputStream extends java.io.FilterOutputStream {
1855         
1856         private boolean encode;
1857         private int     position;
1858         private byte[]  buffer;
1859         private int     bufferLength;
1860         private int     lineLength;
1861         private boolean breakLines;
1862         private byte[]  b4;         // Scratch used in a few places
1863         private boolean suspendEncoding;
1864         private int     options;    // Record for later
1865         private byte[]  decodabet;  // Local copies to avoid extra method calls
1866         
1867         /**
1868          * Constructs a {@link Base64.OutputStream} in ENCODE mode.
1869          *
1870          * @param out the <tt>java.io.OutputStream</tt> to which data will be written.
1871          * @since 1.3
1872          */
1873         public OutputStream( java.io.OutputStream out ) {
1874             this( out, ENCODE );
1875         }   // end constructor
1876         
1877         
1878         /**
1879          * Constructs a {@link Base64.OutputStream} in
1880          * either ENCODE or DECODE mode.
1881          * <p>
1882          * Valid options:<pre>
1883          *   ENCODE or DECODE: Encode or Decode as data is read.
1884          *   DO_BREAK_LINES: don't break lines at 76 characters
1885          *     (only meaningful when encoding)</i>
1886          * </pre>
1887          * <p>
1888          * Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>
1889          *
1890          * @param out the <tt>java.io.OutputStream</tt> to which data will be written.
1891          * @param options Specified options.
1892          * @see Base64#ENCODE
1893          * @see Base64#DECODE
1894          * @see Base64#DO_BREAK_LINES
1895          * @since 1.3
1896          */
1897         public OutputStream( java.io.OutputStream out, int options ) {
1898             super( out );
1899             this.breakLines   = (options & DO_BREAK_LINES) != 0;
1900             this.encode       = (options & ENCODE) != 0;
1901             this.bufferLength = encode ? 3 : 4;
1902             this.buffer       = new byte[ bufferLength ];
1903             this.position     = 0;
1904             this.lineLength   = 0;
1905             this.suspendEncoding = false;
1906             this.b4           = new byte[4];
1907             this.options      = options;
1908             this.decodabet    = getDecodabet(options);
1909         }   // end constructor
1910         
1911         
1912         /**
1913          * Writes the byte to the output stream after
1914          * converting to/from Base64 notation.
1915          * When encoding, bytes are buffered three
1916          * at a time before the output stream actually
1917          * gets a write() call.
1918          * When decoding, bytes are buffered four
1919          * at a time.
1920          *
1921          * @param theByte the byte to write
1922          * @since 1.3
1923          */
1924         @Override
1925         public void write(int theByte) 
1926         throws java.io.IOException {
1927             // Encoding suspended?
1928             if( suspendEncoding ) {
1929                 this.out.write( theByte );
1930                 return;
1931             }   // end if: supsended
1932             
1933             // Encode?
1934             if( encode ) {
1935                 buffer[ position++ ] = (byte)theByte;
1936                 if( position >= bufferLength ) { // Enough to encode.
1937                 
1938                     this.out.write( encode3to4( b4, buffer, bufferLength, options ) );
1939 
1940                     lineLength += 4;
1941                     if( breakLines && lineLength >= MAX_LINE_LENGTH ) {
1942                         this.out.write( NEW_LINE );
1943                         lineLength = 0;
1944                     }   // end if: end of line
1945 
1946                     position = 0;
1947                 }   // end if: enough to output
1948             }   // end if: encoding
1949 
1950             // Else, Decoding
1951             else {
1952                 // Meaningful Base64 character?
1953                 if( decodabet[ theByte & 0x7f ] > WHITE_SPACE_ENC ) {
1954                     buffer[ position++ ] = (byte)theByte;
1955                     if( position >= bufferLength ) { // Enough to output.
1956                     
1957                         int len = Base64.decode4to3( buffer, 0, b4, 0, options );
1958                         out.write( b4, 0, len );
1959                         position = 0;
1960                     }   // end if: enough to output
1961                 }   // end if: meaningful base64 character
1962                 else if( decodabet[ theByte & 0x7f ] != WHITE_SPACE_ENC ) {
1963                     throw new java.io.IOException( "Invalid character in Base64 data." );
1964                 }   // end else: not white space either
1965             }   // end else: decoding
1966         }   // end write
1967         
1968         
1969         
1970         /**
1971          * Calls {@link #write(int)} repeatedly until <var>len</var> 
1972          * bytes are written.
1973          *
1974          * @param theBytes array from which to read bytes
1975          * @param off offset for array
1976          * @param len max number of bytes to read into array
1977          * @since 1.3
1978          */
1979         @Override
1980         public void write( byte[] theBytes, int off, int len ) 
1981         throws java.io.IOException {
1982             // Encoding suspended?
1983             if( suspendEncoding ) {
1984                 this.out.write( theBytes, off, len );
1985                 return;
1986             }   // end if: supsended
1987             
1988             for( int i = 0; i < len; i++ ) {
1989                 write( theBytes[ off + i ] );
1990             }   // end for: each byte written
1991             
1992         }   // end write
1993         
1994         
1995         
1996         /**
1997          * Method added by PHIL. [Thanks, PHIL. -Rob]
1998          * This pads the buffer without closing the stream.
1999          * @throws java.io.IOException  if there's an error.
2000          */
2001         public void flushBase64() throws java.io.IOException  {
2002             if( position > 0 ) {
2003                 if( encode ) {
2004                     out.write( encode3to4( b4, buffer, position, options ) );
2005                     position = 0;
2006                 }   // end if: encoding
2007                 else {
2008                     throw new java.io.IOException( "Base64 input not properly padded." );
2009                 }   // end else: decoding
2010             }   // end if: buffer partially full
2011 
2012         }   // end flush
2013 
2014         
2015         /** 
2016          * Flushes and closes (I think, in the superclass) the stream. 
2017          *
2018          * @since 1.3
2019          */
2020         @Override
2021         public void close() throws java.io.IOException {
2022             // 1. Ensure that pending characters are written
2023             flushBase64();
2024 
2025             // 2. Actually close the stream
2026             // Base class both flushes and closes.
2027             super.close();
2028             
2029             buffer = null;
2030             out    = null;
2031         }   // end close
2032         
2033         
2034         
2035         /**
2036          * Suspends encoding of the stream.
2037          * May be helpful if you need to embed a piece of
2038          * base64-encoded data in a stream.
2039          *
2040          * @throws java.io.IOException  if there's an error flushing
2041          * @since 1.5.1
2042          */
2043         public void suspendEncoding() throws java.io.IOException  {
2044             flushBase64();
2045             this.suspendEncoding = true;
2046         }   // end suspendEncoding
2047         
2048         
2049         /**
2050          * Resumes encoding of the stream.
2051          * May be helpful if you need to embed a piece of
2052          * base64-encoded data in a stream.
2053          *
2054          * @since 1.5.1
2055          */
2056         public void resumeEncoding() {
2057             this.suspendEncoding = false;
2058         }   // end resumeEncoding
2059         
2060         
2061         
2062     }   // end inner class OutputStream
2063     
2064     
2065 }   // end class Base64