001package com.randomnoun.common;
002
003/* (c) 2013 randomnoun. All Rights Reserved. This work is licensed under a
004 * BSD Simplified License. (http://www.randomnoun.com/bsd-simplified.html)
005 */
006
007// this class was taken from the widen valet (aws route53) package 
008
009/**
010 * <p>Encodes and decodes to and from Base64 notation.</p>
011 * <p>Homepage: <a href="http://iharder.net/base64">http://iharder.net/base64</a>.</p>
012 * 
013 * <p>Example:</p>
014 * 
015 * <p><code>String encoded = Base64.encode( myByteArray );</code></p>
016 * 
017 * <p><code>byte[] myByteArray = Base64.decode( encoded );</code></p>
018 *
019 * <p>The <code>options</code> parameter, which appears in a few places, is used to pass 
020 * several pieces of information to the encoder. In the "higher level" methods such as 
021 * encodeBytes( bytes, options ) the options parameter can be used to indicate such 
022 * things as first gzipping the bytes before encoding them, not inserting linefeeds,
023 * and encoding using the URL-safe and Ordered dialects.</p>
024 *
025 * <p>Note, according to <a href="http://www.faqs.org/rfcs/rfc3548.html">RFC3548</a>,
026 * Section 2.1, implementations should not add line feeds unless explicitly told
027 * to do so. I've got Base64 set to this behavior now, although earlier versions
028 * broke lines by default.</p>
029 *
030 * <p>The constants defined in Base64 can be OR-ed together to combine options, so you 
031 * might make a call like this:</p>
032 *
033 * <code>String encoded = Base64.encodeBytes( mybytes, Base64.GZIP | Base64.DO_BREAK_LINES );</code>
034 * <p>to compress the data before encoding it and then making the output have newline characters.</p>
035 * <p>Also...</p>
036 * <code>String encoded = Base64.encodeBytes( crazyString.getBytes() );</code>
037 *
038 *
039 *
040 * <p>
041 * Change Log:
042 * </p>
043 * <ul>
044 *  <li>v2.3.7 - Fixed subtle bug when base 64 input stream contained the
045 *   value 01111111, which is an invalid base 64 character but should not
046 *   throw an ArrayIndexOutOfBoundsException either. Led to discovery of
047 *   mishandling (or potential for better handling) of other bad input
048 *   characters. You should now get an IOException if you try decoding
049 *   something that has bad characters in it.</li>
050 *  <li>v2.3.6 - Fixed bug when breaking lines and the final byte of the encoded
051 *   string ended in the last column; the buffer was not properly shrunk and
052 *   contained an extra (null) byte that made it into the string.</li>
053 *  <li>v2.3.5 - Fixed bug in {@link #encodeFromFile} where estimated buffer size
054 *   was wrong for files of size 31, 34, and 37 bytes.</li>
055 *  <li>v2.3.4 - Fixed bug when working with gzipped streams whereby flushing
056 *   the Base64.OutputStream closed the Base64 encoding (by padding with equals
057 *   signs) too soon. Also added an option to suppress the automatic decoding
058 *   of gzipped streams. Also added experimental support for specifying a
059 *   class loader when using the
060 *   {@link #decodeToObject(String, int, ClassLoader)}
061 *   method.</li>
062 *  <li>v2.3.3 - Changed default char encoding to US-ASCII which reduces the internal Java
063 *   footprint with its CharEncoders and so forth. Fixed some javadocs that were
064 *   inconsistent. Removed imports and specified things like java.io.IOException
065 *   explicitly inline.</li>
066 *  <li>v2.3.2 - Reduced memory footprint! Finally refined the "guessing" of how big the
067 *   final encoded data will be so that the code doesn't have to create two output
068 *   arrays: an oversized initial one and then a final, exact-sized one. Big win
069 *   when using the {@link #encodeBytesToBytes(byte[])} family of methods (and not
070 *   using the gzip options which uses a different mechanism with streams and stuff).</li>
071 *  <li>v2.3.1 - Added {@link #encodeBytesToBytes(byte[], int, int, int)} and some
072 *   similar helper methods to be more efficient with memory by not returning a
073 *   String but just a byte array.</li>
074 *  <li>v2.3 - <strong>This is not a drop-in replacement!</strong> This is two years of comments
075 *   and bug fixes queued up and finally executed. Thanks to everyone who sent
076 *   me stuff, and I'm sorry I wasn't able to distribute your fixes to everyone else.
077 *   Much bad coding was cleaned up including throwing exceptions where necessary 
078 *   instead of returning null values or something similar. Here are some changes
079 *   that may affect you:
080 *   <ul>
081 *    <li><em>Does not break lines, by default.</em> This is to keep in compliance with
082 *      <a href="http://www.faqs.org/rfcs/rfc3548.html">RFC3548</a>.</li>
083 *    <li><em>Throws exceptions instead of returning null values.</em> Because some operations
084 *      (especially those that may permit the GZIP option) use IO streams, there
085 *      is a possiblity of an java.io.IOException being thrown. After some discussion and
086 *      thought, I've changed the behavior of the methods to throw java.io.IOExceptions
087 *      rather than return null if ever there's an error. I think this is more
088 *      appropriate, though it will require some changes to your code. Sorry,
089 *      it should have been done this way to begin with.</li>
090 *    <li><em>Removed all references to System.out, System.err, and the like.</em>
091 *      Shame on me. All I can say is sorry they were ever there.</li>
092 *    <li><em>Throws NullPointerExceptions and IllegalArgumentExceptions</em> as needed
093 *      such as when passed arrays are null or offsets are invalid.</li>
094 *    <li>Cleaned up as much javadoc as I could to avoid any javadoc warnings.
095 *      This was especially annoying before for people who were thorough in their
096 *      own projects and then had gobs of javadoc warnings on this file.</li>
097 *   </ul>
098 *  <li>v2.2.1 - Fixed bug using URL_SAFE and ORDERED encodings. Fixed bug
099 *   when using very small files (~&lt; 40 bytes).</li>
100 *  <li>v2.2 - Added some helper methods for encoding/decoding directly from
101 *   one file to the next. Also added a main() method to support command line
102 *   encoding/decoding from one file to the next. Also added these Base64 dialects:
103 *   <ol>
104 *   <li>The default is RFC3548 format.</li>
105 *   <li>Calling Base64.setFormat(Base64.BASE64_FORMAT.URLSAFE_FORMAT) generates
106 *   URL and file name friendly format as described in Section 4 of RFC3548.
107 *   http://www.faqs.org/rfcs/rfc3548.html</li>
108 *   <li>Calling Base64.setFormat(Base64.BASE64_FORMAT.ORDERED_FORMAT) generates
109 *   URL and file name friendly format that preserves lexical ordering as described
110 *   in http://www.faqs.org/qa/rfcc-1940.html</li>
111 *   </ol>
112 *   Special thanks to Jim Kellerman at <a href="http://www.powerset.com/">http://www.powerset.com/</a>
113 *   for contributing the new Base64 dialects.
114 *  </li>
115 * 
116 *  <li>v2.1 - Cleaned up javadoc comments and unused variables and methods. Added
117 *   some convenience methods for reading and writing to and from files.</li>
118 *  <li>v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems
119 *   with other encodings (like EBCDIC).</li>
120 *  <li>v2.0.1 - Fixed an error when decoding a single byte, that is, when the
121 *   encoded data was a single byte.</li>
122 *  <li>v2.0 - I got rid of methods that used booleans to set options. 
123 *   Now everything is more consolidated and cleaner. The code now detects
124 *   when data that's being decoded is gzip-compressed and will decompress it
125 *   automatically. Generally things are cleaner. You'll probably have to
126 *   change some method calls that you were making to support the new
127 *   options format (<code>int</code>s that you "OR" together).</li>
128 *  <li>v1.5.1 - Fixed bug when decompressing and decoding to a             
129 *   byte[] using <code>decode( String s, boolean gzipCompressed )</code>.      
130 *   Added the ability to "suspend" encoding in the Output Stream so        
131 *   you can turn on and off the encoding if you need to embed base64       
132 *   data in an otherwise "normal" stream (like an XML file).</li>  
133 *  <li>v1.5 - Output stream pases on flush() command but doesn't do anything itself.
134 *      This helps when using GZIP streams.
135 *      Added the ability to GZip-compress objects before encoding them.</li>
136 *  <li>v1.4 - Added helper methods to read/write files.</li>
137 *  <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li>
138 *  <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream
139 *      where last buffer being read, if not completely full, was not returned.</li>
140 *  <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.</li>
141 *  <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
142 * </ul>
143 *
144 * <p>
145 * I am placing this code in the Public Domain. Do with it as you will.
146 * This software comes with no guarantees or warranties but with
147 * plenty of well-wishing instead!
148 * Please visit <a href="http://iharder.net/base64">http://iharder.net/base64</a>
149 * periodically to check for updates or to contribute improvements.
150 * </p>
151 *
152 * @author Robert Harder
153 * @author rob@iharder.net
154 * @version 2.3.7
155 */
156public class Base64
157{
158    
159    
160
161    
162/* ********  P U B L I C   F I E L D S  ******** */   
163    
164    
165    /** No options specified. Value is zero. */
166    public final static int NO_OPTIONS = 0;
167    
168    /** Specify encoding in first bit. Value is one. */
169    public final static int ENCODE = 1;
170    
171    
172    /** Specify decoding in first bit. Value is zero. */
173    public final static int DECODE = 0;
174    
175
176    /** Specify that data should be gzip-compressed in second bit. Value is two. */
177    public final static int GZIP = 2;
178
179    /** Specify that gzipped data should <em>not</em> be automatically gunzipped. */
180    public final static int DONT_GUNZIP = 4;
181    
182    
183    /** Do break lines when encoding. Value is 8. */
184    public final static int DO_BREAK_LINES = 8;
185        
186    /** 
187     * Encode using Base64-like encoding that is URL- and Filename-safe as described
188     * in Section 4 of RFC3548: 
189     * <a href="http://www.faqs.org/rfcs/rfc3548.html">http://www.faqs.org/rfcs/rfc3548.html</a>.
190     * It is important to note that data encoded this way is <em>not</em> officially valid Base64, 
191     * or at the very least should not be called Base64 without also specifying that is
192     * was encoded using the URL- and Filename-safe dialect.
193     */
194     public final static int URL_SAFE = 16;
195
196
197     /**
198      * Encode using the special "ordered" dialect of Base64 described here:
199      * <a href="http://www.faqs.org/qa/rfcc-1940.html">http://www.faqs.org/qa/rfcc-1940.html</a>.
200      */
201     public final static int ORDERED = 32;
202    
203    
204/* ********  P R I V A T E   F I E L D S  ******** */  
205    
206    
207    /** Maximum line length (76) of Base64 output. */
208    private final static int MAX_LINE_LENGTH = 76;
209    
210    
211    /** The equals sign (=) as a byte. */
212    private final static byte EQUALS_SIGN = (byte)'=';
213    
214    
215    /** The new line character (\n) as a byte. */
216    private final static byte NEW_LINE = (byte)'\n';
217    
218    
219    /** Preferred encoding. */
220    private final static String PREFERRED_ENCODING = "US-ASCII";
221    
222        
223    private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding
224    private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding
225        
226        
227/* ********  S T A N D A R D   B A S E 6 4   A L P H A B E T  ******** */       
228    
229    /** The 64 valid Base64 values. */
230    /* Host platform me be something funny like EBCDIC, so we hardcode these values. */
231    private final static byte[] _STANDARD_ALPHABET = {
232        (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
233        (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
234        (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', 
235        (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
236        (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
237        (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
238        (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', 
239        (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z',
240        (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', 
241        (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/'
242    };
243        
244    
245    /** 
246     * Translates a Base64 value to either its 6-bit reconstruction value
247     * or a negative number indicating some other meaning.
248     **/
249    private final static byte[] _STANDARD_DECODABET = {
250        -9,-9,-9,-9,-9,-9,-9,-9,-9,                 // Decimal  0 -  8
251        -5,-5,                                      // Whitespace: Tab and Linefeed
252        -9,-9,                                      // Decimal 11 - 12
253        -5,                                         // Whitespace: Carriage Return
254        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 14 - 26
255        -9,-9,-9,-9,-9,                             // Decimal 27 - 31
256        -5,                                         // Whitespace: Space
257        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,              // Decimal 33 - 42
258        62,                                         // Plus sign at decimal 43
259        -9,-9,-9,                                   // Decimal 44 - 46
260        63,                                         // Slash at decimal 47
261        52,53,54,55,56,57,58,59,60,61,              // Numbers zero through nine
262        -9,-9,-9,                                   // Decimal 58 - 60
263        -1,                                         // Equals sign at decimal 61
264        -9,-9,-9,                                      // Decimal 62 - 64
265        0,1,2,3,4,5,6,7,8,9,10,11,12,13,            // Letters 'A' through 'N'
266        14,15,16,17,18,19,20,21,22,23,24,25,        // Letters 'O' through 'Z'
267        -9,-9,-9,-9,-9,-9,                          // Decimal 91 - 96
268        26,27,28,29,30,31,32,33,34,35,36,37,38,     // Letters 'a' through 'm'
269        39,40,41,42,43,44,45,46,47,48,49,50,51,     // Letters 'n' through 'z'
270        -9,-9,-9,-9,-9                              // Decimal 123 - 127
271        ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,       // Decimal 128 - 139
272        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
273        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
274        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
275        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
276        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
277        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
278        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
279        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
280        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 
281    };
282        
283        
284/* ********  U R L   S A F E   B A S E 6 4   A L P H A B E T  ******** */
285        
286    /**
287     * Used in the URL- and Filename-safe dialect described in Section 4 of RFC3548: 
288     * <a href="http://www.faqs.org/rfcs/rfc3548.html">http://www.faqs.org/rfcs/rfc3548.html</a>.
289     * Notice that the last two bytes become "hyphen" and "underscore" instead of "plus" and "slash."
290     */
291    private final static byte[] _URL_SAFE_ALPHABET = {
292      (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
293      (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
294      (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', 
295      (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
296      (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
297      (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
298      (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', 
299      (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z',
300      (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', 
301      (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'-', (byte)'_'
302    };
303        
304    /**
305     * Used in decoding URL- and Filename-safe dialects of Base64.
306     */
307    private final static byte[] _URL_SAFE_DECODABET = {
308      -9,-9,-9,-9,-9,-9,-9,-9,-9,                 // Decimal  0 -  8
309      -5,-5,                                      // Whitespace: Tab and Linefeed
310      -9,-9,                                      // Decimal 11 - 12
311      -5,                                         // Whitespace: Carriage Return
312      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 14 - 26
313      -9,-9,-9,-9,-9,                             // Decimal 27 - 31
314      -5,                                         // Whitespace: Space
315      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,              // Decimal 33 - 42
316      -9,                                         // Plus sign at decimal 43
317      -9,                                         // Decimal 44
318      62,                                         // Minus sign at decimal 45
319      -9,                                         // Decimal 46
320      -9,                                         // Slash at decimal 47
321      52,53,54,55,56,57,58,59,60,61,              // Numbers zero through nine
322      -9,-9,-9,                                   // Decimal 58 - 60
323      -1,                                         // Equals sign at decimal 61
324      -9,-9,-9,                                   // Decimal 62 - 64
325      0,1,2,3,4,5,6,7,8,9,10,11,12,13,            // Letters 'A' through 'N'
326      14,15,16,17,18,19,20,21,22,23,24,25,        // Letters 'O' through 'Z'
327      -9,-9,-9,-9,                                // Decimal 91 - 94
328      63,                                         // Underscore at decimal 95
329      -9,                                         // Decimal 96
330      26,27,28,29,30,31,32,33,34,35,36,37,38,     // Letters 'a' through 'm'
331      39,40,41,42,43,44,45,46,47,48,49,50,51,     // Letters 'n' through 'z'
332      -9,-9,-9,-9,-9                              // Decimal 123 - 127
333      ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 128 - 139
334      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
335      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
336      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
337      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
338      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
339      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
340      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
341      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
342      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 
343    };
344
345
346
347/* ********  O R D E R E D   B A S E 6 4   A L P H A B E T  ******** */
348
349    /**
350     * I don't get the point of this technique, but someone requested it,
351     * and it is described here:
352     * <a href="http://www.faqs.org/qa/rfcc-1940.html">http://www.faqs.org/qa/rfcc-1940.html</a>.
353     */
354    private final static byte[] _ORDERED_ALPHABET = {
355      (byte)'-',
356      (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4',
357      (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9',
358      (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
359      (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
360      (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
361      (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
362      (byte)'_',
363      (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
364      (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
365      (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
366      (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z'
367    };
368        
369    /**
370     * Used in decoding the "ordered" dialect of Base64.
371     */
372    private final static byte[] _ORDERED_DECODABET = {
373      -9,-9,-9,-9,-9,-9,-9,-9,-9,                 // Decimal  0 -  8
374      -5,-5,                                      // Whitespace: Tab and Linefeed
375      -9,-9,                                      // Decimal 11 - 12
376      -5,                                         // Whitespace: Carriage Return
377      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 14 - 26
378      -9,-9,-9,-9,-9,                             // Decimal 27 - 31
379      -5,                                         // Whitespace: Space
380      -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,              // Decimal 33 - 42
381      -9,                                         // Plus sign at decimal 43
382      -9,                                         // Decimal 44
383      0,                                          // Minus sign at decimal 45
384      -9,                                         // Decimal 46
385      -9,                                         // Slash at decimal 47
386      1,2,3,4,5,6,7,8,9,10,                       // Numbers zero through nine
387      -9,-9,-9,                                   // Decimal 58 - 60
388      -1,                                         // Equals sign at decimal 61
389      -9,-9,-9,                                   // Decimal 62 - 64
390      11,12,13,14,15,16,17,18,19,20,21,22,23,     // Letters 'A' through 'M'
391      24,25,26,27,28,29,30,31,32,33,34,35,36,     // Letters 'N' through 'Z'
392      -9,-9,-9,-9,                                // Decimal 91 - 94
393      37,                                         // Underscore at decimal 95
394      -9,                                         // Decimal 96
395      38,39,40,41,42,43,44,45,46,47,48,49,50,     // Letters 'a' through 'm'
396      51,52,53,54,55,56,57,58,59,60,61,62,63,     // Letters 'n' through 'z'
397      -9,-9,-9,-9,-9                                 // Decimal 123 - 127
398       ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 128 - 139
399        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
400        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
401        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
402        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
403        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
404        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
405        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
406        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
407        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 
408    };
409
410        
411/* ********  D E T E R M I N E   W H I C H   A L H A B E T  ******** */
412
413
414    /**
415     * Returns one of the _SOMETHING_ALPHABET byte arrays depending on
416     * the options specified.
417     * It's possible, though silly, to specify ORDERED <b>and</b> URLSAFE
418     * in which case one of them will be picked, though there is
419     * no guarantee as to which one will be picked.
420     */
421    private final static byte[] getAlphabet( int options ) {
422        if ((options & URL_SAFE) == URL_SAFE) {
423            return _URL_SAFE_ALPHABET;
424        } else if ((options & ORDERED) == ORDERED) {
425            return _ORDERED_ALPHABET;
426        } else {
427            return _STANDARD_ALPHABET;
428        }
429    }   // end getAlphabet
430
431
432    /**
433     * Returns one of the _SOMETHING_DECODABET byte arrays depending on
434     * the options specified.
435     * It's possible, though silly, to specify ORDERED and URL_SAFE
436     * in which case one of them will be picked, though there is
437     * no guarantee as to which one will be picked.
438     */
439    private final static byte[] getDecodabet( int options ) {
440        if( (options & URL_SAFE) == URL_SAFE) {
441            return _URL_SAFE_DECODABET;
442        } else if ((options & ORDERED) == ORDERED) {
443            return _ORDERED_DECODABET;
444        } else {
445            return _STANDARD_DECODABET;
446        }
447    }   // end getAlphabet
448
449
450    
451    /** Defeats instantiation. */
452    private Base64(){}
453    
454
455    
456    
457/* ********  E N C O D I N G   M E T H O D S  ******** */    
458    
459    
460    /**
461     * Encodes up to the first three bytes of array <var>threeBytes</var>
462     * and returns a four-byte array in Base64 notation.
463     * The actual number of significant bytes in your array is
464     * given by <var>numSigBytes</var>.
465     * The array <var>threeBytes</var> needs only be as big as
466     * <var>numSigBytes</var>.
467     * Code can reuse a byte array by passing a four-byte array as <var>b4</var>.
468     *
469     * @param b4 A reusable byte array to reduce array instantiation
470     * @param threeBytes the array to convert
471     * @param numSigBytes the number of significant bytes in your array
472     * @return four byte array in Base64 notation.
473     * @since 1.5.1
474     */
475    private static byte[] encode3to4( byte[] b4, byte[] threeBytes, int numSigBytes, int options ) {
476        encode3to4( threeBytes, 0, numSigBytes, b4, 0, options );
477        return b4;
478    }   // end encode3to4
479
480    
481    /**
482     * <p>Encodes up to three bytes of the array <var>source</var>
483     * and writes the resulting four Base64 bytes to <var>destination</var>.
484     * The source and destination arrays can be manipulated
485     * anywhere along their length by specifying 
486     * <var>srcOffset</var> and <var>destOffset</var>.
487     * This method does not check to make sure your arrays
488     * are large enough to accomodate <var>srcOffset</var> + 3 for
489     * the <var>source</var> array or <var>destOffset</var> + 4 for
490     * the <var>destination</var> array.
491     * The actual number of significant bytes in your array is
492     * given by <var>numSigBytes</var>.</p>
493         * <p>This is the lowest level of the encoding methods with
494         * all possible parameters.</p>
495     *
496     * @param source the array to convert
497     * @param srcOffset the index where conversion begins
498     * @param numSigBytes the number of significant bytes in your array
499     * @param destination the array to hold the conversion
500     * @param destOffset the index where output will be put
501     * @return the <var>destination</var> array
502     * @since 1.3
503     */
504    private static byte[] encode3to4( 
505    byte[] source, int srcOffset, int numSigBytes,
506    byte[] destination, int destOffset, int options ) {
507        
508        byte[] ALPHABET = getAlphabet( options ); 
509        
510        //           1         2         3  
511        // 01234567890123456789012345678901 Bit position
512        // --------000000001111111122222222 Array position from threeBytes
513        // --------|    ||    ||    ||    | Six bit groups to index ALPHABET
514        //          >>18  >>12  >> 6  >> 0  Right shift necessary
515        //                0x3f  0x3f  0x3f  Additional AND
516        
517        // Create buffer with zero-padding if there are only one or two
518        // significant bytes passed in the array.
519        // We have to shift left 24 in order to flush out the 1's that appear
520        // when Java treats a value as negative that is cast from a byte to an int.
521        int inBuff =   ( numSigBytes > 0 ? ((source[ srcOffset     ] << 24) >>>  8) : 0 )
522                     | ( numSigBytes > 1 ? ((source[ srcOffset + 1 ] << 24) >>> 16) : 0 )
523                     | ( numSigBytes > 2 ? ((source[ srcOffset + 2 ] << 24) >>> 24) : 0 );
524
525        switch( numSigBytes )
526        {
527            case 3:
528                destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
529                destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
530                destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>>  6) & 0x3f ];
531                destination[ destOffset + 3 ] = ALPHABET[ (inBuff       ) & 0x3f ];
532                return destination;
533                
534            case 2:
535                destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
536                destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
537                destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>>  6) & 0x3f ];
538                destination[ destOffset + 3 ] = EQUALS_SIGN;
539                return destination;
540                
541            case 1:
542                destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
543                destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
544                destination[ destOffset + 2 ] = EQUALS_SIGN;
545                destination[ destOffset + 3 ] = EQUALS_SIGN;
546                return destination;
547                
548            default:
549                return destination;
550        }   // end switch
551    }   // end encode3to4
552
553
554
555    /**
556     * Performs Base64 encoding on the <code>raw</code> ByteBuffer,
557     * writing it to the <code>encoded</code> ByteBuffer.
558     * This is an experimental feature. Currently it does not
559     * pass along any options (such as {@link #DO_BREAK_LINES}
560     * or {@link #GZIP}.
561     *
562     * @param raw input buffer
563     * @param encoded output buffer
564     * @since 2.3
565     */
566    public static void encode( java.nio.ByteBuffer raw, java.nio.ByteBuffer encoded ){
567        byte[] raw3 = new byte[3];
568        byte[] enc4 = new byte[4];
569
570        while( raw.hasRemaining() ){
571            int rem = Math.min(3,raw.remaining());
572            raw.get(raw3,0,rem);
573            Base64.encode3to4(enc4, raw3, rem, Base64.NO_OPTIONS );
574            encoded.put(enc4);
575        }   // end input remaining
576    }
577
578
579    /**
580     * Performs Base64 encoding on the <code>raw</code> ByteBuffer,
581     * writing it to the <code>encoded</code> CharBuffer.
582     * This is an experimental feature. Currently it does not
583     * pass along any options (such as {@link #DO_BREAK_LINES}
584     * or {@link #GZIP}.
585     *
586     * @param raw input buffer
587     * @param encoded output buffer
588     * @since 2.3
589     */
590    public static void encode( java.nio.ByteBuffer raw, java.nio.CharBuffer encoded ){
591        byte[] raw3 = new byte[3];
592        byte[] enc4 = new byte[4];
593
594        while( raw.hasRemaining() ){
595            int rem = Math.min(3,raw.remaining());
596            raw.get(raw3,0,rem);
597            Base64.encode3to4(enc4, raw3, rem, Base64.NO_OPTIONS );
598            for( int i = 0; i < 4; i++ ){
599                encoded.put( (char)(enc4[i] & 0xFF) );
600            }
601        }   // end input remaining
602    }
603
604
605    
606    
607    /**
608     * Serializes an object and returns the Base64-encoded
609     * version of that serialized object.  
610     *  
611     * <p>As of v 2.3, if the object
612     * cannot be serialized or there is another error,
613     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
614     * In earlier versions, it just returned a null value, but
615     * in retrospect that's a pretty poor way to handle it.</p>
616     * 
617     * The object is not GZip-compressed before being encoded.
618     *
619     * @param serializableObject The object to encode
620     * @return The Base64-encoded object
621     * @throws java.io.IOException if there is an error
622     * @throws NullPointerException if serializedObject is null
623     * @since 1.4
624     */
625    public static String encodeObject( java.io.Serializable serializableObject )
626    throws java.io.IOException {
627        return encodeObject( serializableObject, NO_OPTIONS );
628    }   // end encodeObject
629    
630
631
632    /**
633     * Serializes an object and returns the Base64-encoded
634     * version of that serialized object.
635     *  
636     * <p>As of v 2.3, if the object
637     * cannot be serialized or there is another error,
638     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
639     * In earlier versions, it just returned a null value, but
640     * in retrospect that's a pretty poor way to handle it.</p>
641     * 
642     * The object is not GZip-compressed before being encoded.
643     * <p>
644     * Example options:<pre>
645     *   GZIP: gzip-compresses object before encoding it.
646     *   DO_BREAK_LINES: break lines at 76 characters
647     * </pre>
648     * <p>
649     * Example: <code>encodeObject( myObj, Base64.GZIP )</code> or
650     * <p>
651     * Example: <code>encodeObject( myObj, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
652     *
653     * @param serializableObject The object to encode
654     * @param options Specified options
655     * @return The Base64-encoded object
656     * @see Base64#GZIP
657     * @see Base64#DO_BREAK_LINES
658     * @throws java.io.IOException if there is an error
659     * @since 2.0
660     */
661    public static String encodeObject( java.io.Serializable serializableObject, int options )
662    throws java.io.IOException {
663
664        if( serializableObject == null ){
665            throw new NullPointerException( "Cannot serialize a null object." );
666        }   // end if: null
667        
668        // Streams
669        java.io.ByteArrayOutputStream  baos  = null; 
670        java.io.OutputStream           b64os = null;
671        java.util.zip.GZIPOutputStream gzos  = null;
672        java.io.ObjectOutputStream     oos   = null;
673        
674        
675        try {
676            // ObjectOutputStream -> (GZIP) -> Base64 -> ByteArrayOutputStream
677            baos  = new java.io.ByteArrayOutputStream();
678            b64os = new OutputStream( baos, ENCODE | options );
679            if( (options & GZIP) != 0 ){
680                // Gzip
681                gzos = new java.util.zip.GZIPOutputStream(b64os);
682                oos = new java.io.ObjectOutputStream( gzos );
683            } else {
684                // Not gzipped
685                oos = new java.io.ObjectOutputStream( b64os );
686            }
687            oos.writeObject( serializableObject );
688        }   // end try
689        catch( java.io.IOException e ) {
690            // Catch it and then throw it immediately so that
691            // the finally{} block is called for cleanup.
692            throw e;
693        }   // end catch
694        finally {
695            try{ oos.close();   } catch( Exception e ){}
696            try{ gzos.close();  } catch( Exception e ){}
697            try{ b64os.close(); } catch( Exception e ){}
698            try{ baos.close();  } catch( Exception e ){}
699        }   // end finally
700        
701        // Return value according to relevant encoding.
702        try {
703            return new String( baos.toByteArray(), PREFERRED_ENCODING );
704        }   // end try
705        catch (java.io.UnsupportedEncodingException uue){
706            // Fall back to some Java default
707            return new String( baos.toByteArray() );
708        }   // end catch
709        
710    }   // end encode
711    
712    
713
714    /**
715     * Encodes a byte array into Base64 notation.
716     * Does not GZip-compress data.
717     *  
718     * @param source The data to convert
719     * @return The data in Base64-encoded form
720     * @throws NullPointerException if source array is null
721     * @since 1.4
722     */
723    public static String encodeBytes( byte[] source ) {
724        // Since we're not going to have the GZIP encoding turned on,
725        // we're not going to have an java.io.IOException thrown, so
726        // we should not force the user to have to catch it.
727        String encoded = null;
728        try {
729            encoded = encodeBytes(source, 0, source.length, NO_OPTIONS);
730        } catch (java.io.IOException ex) {
731            assert false : ex.getMessage();
732        }   // end catch
733        assert encoded != null;
734        return encoded;
735    }   // end encodeBytes
736    
737
738
739    /**
740     * Encodes a byte array into Base64 notation.
741     * <p>
742     * Example options:<pre>
743     *   GZIP: gzip-compresses object before encoding it.
744     *   DO_BREAK_LINES: break lines at 76 characters
745     *     <i>Note: Technically, this makes your encoding non-compliant.</i>
746     * </pre>
747     * <p>
748     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
749     * <p>
750     * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
751     *
752     *  
753     * <p>As of v 2.3, if there is an error with the GZIP stream,
754     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
755     * In earlier versions, it just returned a null value, but
756     * in retrospect that's a pretty poor way to handle it.</p>
757     * 
758     *
759     * @param source The data to convert
760     * @param options Specified options
761     * @return The Base64-encoded data as a String
762     * @see Base64#GZIP
763     * @see Base64#DO_BREAK_LINES
764     * @throws java.io.IOException if there is an error
765     * @throws NullPointerException if source array is null
766     * @since 2.0
767     */
768    public static String encodeBytes( byte[] source, int options ) throws java.io.IOException {
769        return encodeBytes( source, 0, source.length, options );
770    }   // end encodeBytes
771    
772    
773    /**
774     * Encodes a byte array into Base64 notation.
775     * Does not GZip-compress data.
776     *  
777     * <p>As of v 2.3, if there is an error,
778     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
779     * In earlier versions, it just returned a null value, but
780     * in retrospect that's a pretty poor way to handle it.</p>
781     * 
782     *
783     * @param source The data to convert
784     * @param off Offset in array where conversion should begin
785     * @param len Length of data to convert
786     * @return The Base64-encoded data as a String
787     * @throws NullPointerException if source array is null
788     * @throws IllegalArgumentException if source array, offset, or length are invalid
789     * @since 1.4
790     */
791    public static String encodeBytes( byte[] source, int off, int len ) {
792        // Since we're not going to have the GZIP encoding turned on,
793        // we're not going to have an java.io.IOException thrown, so
794        // we should not force the user to have to catch it.
795        String encoded = null;
796        try {
797            encoded = encodeBytes( source, off, len, NO_OPTIONS );
798        } catch (java.io.IOException ex) {
799            assert false : ex.getMessage();
800        }   // end catch
801        assert encoded != null;
802        return encoded;
803    }   // end encodeBytes
804    
805    
806
807    /**
808     * Encodes a byte array into Base64 notation.
809     * <p>
810     * Example options:<pre>
811     *   GZIP: gzip-compresses object before encoding it.
812     *   DO_BREAK_LINES: break lines at 76 characters
813     *     <i>Note: Technically, this makes your encoding non-compliant.</i>
814     * </pre>
815     * <p>
816     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
817     * <p>
818     * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
819     *
820     *  
821     * <p>As of v 2.3, if there is an error with the GZIP stream,
822     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
823     * In earlier versions, it just returned a null value, but
824     * in retrospect that's a pretty poor way to handle it.</p>
825     * 
826     *
827     * @param source The data to convert
828     * @param off Offset in array where conversion should begin
829     * @param len Length of data to convert
830     * @param options Specified options
831     * @return The Base64-encoded data as a String
832     * @see Base64#GZIP
833     * @see Base64#DO_BREAK_LINES
834     * @throws java.io.IOException if there is an error
835     * @throws NullPointerException if source array is null
836     * @throws IllegalArgumentException if source array, offset, or length are invalid
837     * @since 2.0
838     */
839    public static String encodeBytes( byte[] source, int off, int len, int options ) throws java.io.IOException {
840        byte[] encoded = encodeBytesToBytes( source, off, len, options );
841
842        // Return value according to relevant encoding.
843        try {
844            return new String( encoded, PREFERRED_ENCODING );
845        }   // end try
846        catch (java.io.UnsupportedEncodingException uue) {
847            return new String( encoded );
848        }   // end catch
849        
850    }   // end encodeBytes
851
852
853
854
855    /**
856     * Similar to {@link #encodeBytes(byte[])} but returns
857     * a byte array instead of instantiating a String. This is more efficient
858     * if you're working with I/O streams and have large data sets to encode.
859     *
860     *
861     * @param source The data to convert
862     * @return The Base64-encoded data as a byte[] (of ASCII characters)
863     * @throws NullPointerException if source array is null
864     * @since 2.3.1
865     */
866    public static byte[] encodeBytesToBytes( byte[] source ) {
867        byte[] encoded = null;
868        try {
869            encoded = encodeBytesToBytes( source, 0, source.length, Base64.NO_OPTIONS );
870        } catch( java.io.IOException ex ) {
871            assert false : "IOExceptions only come from GZipping, which is turned off: " + ex.getMessage();
872        }
873        return encoded;
874    }
875
876
877    /**
878     * Similar to {@link #encodeBytes(byte[], int, int, int)} but returns
879     * a byte array instead of instantiating a String. This is more efficient
880     * if you're working with I/O streams and have large data sets to encode.
881     *
882     *
883     * @param source The data to convert
884     * @param off Offset in array where conversion should begin
885     * @param len Length of data to convert
886     * @param options Specified options
887     * @return The Base64-encoded data as a String
888     * @see Base64#GZIP
889     * @see Base64#DO_BREAK_LINES
890     * @throws java.io.IOException if there is an error
891     * @throws NullPointerException if source array is null
892     * @throws IllegalArgumentException if source array, offset, or length are invalid
893     * @since 2.3.1
894     */
895    public static byte[] encodeBytesToBytes( byte[] source, int off, int len, int options ) throws java.io.IOException {
896
897        if( source == null ){
898            throw new NullPointerException( "Cannot serialize a null array." );
899        }   // end if: null
900
901        if( off < 0 ){
902            throw new IllegalArgumentException( "Cannot have negative offset: " + off );
903        }   // end if: off < 0
904
905        if( len < 0 ){
906            throw new IllegalArgumentException( "Cannot have length offset: " + len );
907        }   // end if: len < 0
908
909        if( off + len > source.length  ){
910            throw new IllegalArgumentException(
911            String.format( "Cannot have offset of %d and length of %d with array of length %d", off,len,source.length));
912        }   // end if: off < 0
913
914
915
916        // Compress?
917        if( (options & GZIP) != 0 ) {
918            java.io.ByteArrayOutputStream  baos  = null;
919            java.util.zip.GZIPOutputStream gzos  = null;
920            OutputStream            b64os = null;
921
922            try {
923                // GZip -> Base64 -> ByteArray
924                baos = new java.io.ByteArrayOutputStream();
925                b64os = new OutputStream( baos, ENCODE | options );
926                gzos  = new java.util.zip.GZIPOutputStream( b64os );
927
928                gzos.write( source, off, len );
929                gzos.close();
930            }   // end try
931            catch( java.io.IOException e ) {
932                // Catch it and then throw it immediately so that
933                // the finally{} block is called for cleanup.
934                throw e;
935            }   // end catch
936            finally {
937                try{ gzos.close();  } catch( Exception e ){}
938                try{ b64os.close(); } catch( Exception e ){}
939                try{ baos.close();  } catch( Exception e ){}
940            }   // end finally
941
942            return baos.toByteArray();
943        }   // end if: compress
944
945        // Else, don't compress. Better not to use streams at all then.
946        else {
947            boolean breakLines = (options & DO_BREAK_LINES) != 0;
948
949            //int    len43   = len * 4 / 3;
950            //byte[] outBuff = new byte[   ( len43 )                      // Main 4:3
951            //                           + ( (len % 3) > 0 ? 4 : 0 )      // Account for padding
952            //                           + (breakLines ? ( len43 / MAX_LINE_LENGTH ) : 0) ]; // New lines
953            // Try to determine more precisely how big the array needs to be.
954            // If we get it right, we don't have to do an array copy, and
955            // we save a bunch of memory.
956            int encLen = ( len / 3 ) * 4 + ( len % 3 > 0 ? 4 : 0 ); // Bytes needed for actual encoding
957            if( breakLines ){
958                encLen += encLen / MAX_LINE_LENGTH; // Plus extra newline characters
959            }
960            byte[] outBuff = new byte[ encLen ];
961
962
963            int d = 0;
964            int e = 0;
965            int len2 = len - 2;
966            int lineLength = 0;
967            for( ; d < len2; d+=3, e+=4 ) {
968                encode3to4( source, d+off, 3, outBuff, e, options );
969
970                lineLength += 4;
971                if( breakLines && lineLength >= MAX_LINE_LENGTH )
972                {
973                    outBuff[e+4] = NEW_LINE;
974                    e++;
975                    lineLength = 0;
976                }   // end if: end of line
977            }   // en dfor: each piece of array
978
979            if( d < len ) {
980                encode3to4( source, d+off, len - d, outBuff, e, options );
981                e += 4;
982            }   // end if: some padding needed
983
984
985            // Only resize array if we didn't guess it right.
986            if( e <= outBuff.length - 1 ){
987                // If breaking lines and the last byte falls right at
988                // the line length (76 bytes per line), there will be
989                // one extra byte, and the array will need to be resized.
990                // Not too bad of an estimate on array size, I'd say.
991                byte[] finalOut = new byte[e];
992                System.arraycopy(outBuff,0, finalOut,0,e);
993                //System.err.println("Having to resize array from " + outBuff.length + " to " + e );
994                return finalOut;
995            } else {
996                //System.err.println("No need to resize array.");
997                return outBuff;
998            }
999        
1000        }   // end else: don't compress
1001
1002    }   // end encodeBytesToBytes
1003    
1004
1005    
1006    
1007    
1008/* ********  D E C O D I N G   M E T H O D S  ******** */
1009    
1010    
1011    /**
1012     * Decodes four bytes from array <var>source</var>
1013     * and writes the resulting bytes (up to three of them)
1014     * to <var>destination</var>.
1015     * The source and destination arrays can be manipulated
1016     * anywhere along their length by specifying 
1017     * <var>srcOffset</var> and <var>destOffset</var>.
1018     * This method does not check to make sure your arrays
1019     * are large enough to accomodate <var>srcOffset</var> + 4 for
1020     * the <var>source</var> array or <var>destOffset</var> + 3 for
1021     * the <var>destination</var> array.
1022     * This method returns the actual number of bytes that 
1023     * were converted from the Base64 encoding.
1024         * <p>This is the lowest level of the decoding methods with
1025         * all possible parameters.</p>
1026     * 
1027     *
1028     * @param source the array to convert
1029     * @param srcOffset the index where conversion begins
1030     * @param destination the array to hold the conversion
1031     * @param destOffset the index where output will be put
1032         * @param options alphabet type is pulled from this (standard, url-safe, ordered)
1033     * @return the number of decoded bytes converted
1034     * @throws NullPointerException if source or destination arrays are null
1035     * @throws IllegalArgumentException if srcOffset or destOffset are invalid
1036     *         or there is not enough room in the array.
1037     * @since 1.3
1038     */
1039    private static int decode4to3( 
1040    byte[] source, int srcOffset, 
1041    byte[] destination, int destOffset, int options ) {
1042        
1043        // Lots of error checking and exception throwing
1044        if( source == null ){
1045            throw new NullPointerException( "Source array was null." );
1046        }   // end if
1047        if( destination == null ){
1048            throw new NullPointerException( "Destination array was null." );
1049        }   // end if
1050        if( srcOffset < 0 || srcOffset + 3 >= source.length ){
1051            throw new IllegalArgumentException( String.format(
1052            "Source array with length %d cannot have offset of %d and still process four bytes.", source.length, srcOffset ) );
1053        }   // end if
1054        if( destOffset < 0 || destOffset +2 >= destination.length ){
1055            throw new IllegalArgumentException( String.format(
1056            "Destination array with length %d cannot have offset of %d and still store three bytes.", destination.length, destOffset ) );
1057        }   // end if
1058        
1059        
1060        byte[] DECODABET = getDecodabet( options ); 
1061        
1062        // Example: Dk==
1063        if( source[ srcOffset + 2] == EQUALS_SIGN ) {
1064            // Two ways to do the same thing. Don't know which way I like best.
1065          //int outBuff =   ( ( DECODABET[ source[ srcOffset    ] ] << 24 ) >>>  6 )
1066          //              | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
1067            int outBuff =   ( ( DECODABET[ source[ srcOffset    ] ] & 0xFF ) << 18 )
1068                          | ( ( DECODABET[ source[ srcOffset + 1] ] & 0xFF ) << 12 );
1069            
1070            destination[ destOffset ] = (byte)( outBuff >>> 16 );
1071            return 1;
1072        }
1073        
1074        // Example: DkL=
1075        else if( source[ srcOffset + 3 ] == EQUALS_SIGN ) {
1076            // Two ways to do the same thing. Don't know which way I like best.
1077          //int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] << 24 ) >>>  6 )
1078          //              | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
1079          //              | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
1080            int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] & 0xFF ) << 18 )
1081                          | ( ( DECODABET[ source[ srcOffset + 1 ] ] & 0xFF ) << 12 )
1082                          | ( ( DECODABET[ source[ srcOffset + 2 ] ] & 0xFF ) <<  6 );
1083            
1084            destination[ destOffset     ] = (byte)( outBuff >>> 16 );
1085            destination[ destOffset + 1 ] = (byte)( outBuff >>>  8 );
1086            return 2;
1087        }
1088        
1089        // Example: DkLE
1090        else {
1091            // Two ways to do the same thing. Don't know which way I like best.
1092          //int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] << 24 ) >>>  6 )
1093          //              | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
1094          //              | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
1095          //              | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
1096            int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] & 0xFF ) << 18 )
1097                          | ( ( DECODABET[ source[ srcOffset + 1 ] ] & 0xFF ) << 12 )
1098                          | ( ( DECODABET[ source[ srcOffset + 2 ] ] & 0xFF ) <<  6)
1099                          | ( ( DECODABET[ source[ srcOffset + 3 ] ] & 0xFF )      );
1100
1101            
1102            destination[ destOffset     ] = (byte)( outBuff >> 16 );
1103            destination[ destOffset + 1 ] = (byte)( outBuff >>  8 );
1104            destination[ destOffset + 2 ] = (byte)( outBuff       );
1105
1106            return 3;
1107        }
1108    }   // end decodeToBytes
1109    
1110
1111
1112
1113
1114    /**
1115     * Low-level access to decoding ASCII characters in
1116     * the form of a byte array. <strong>Ignores GUNZIP option, if
1117     * it's set.</strong> This is not generally a recommended method,
1118     * although it is used internally as part of the decoding process.
1119     * Special case: if len = 0, an empty array is returned. Still,
1120     * if you need more speed and reduced memory footprint (and aren't
1121     * gzipping), consider this method.
1122     *
1123     * @param source The Base64 encoded data
1124     * @return decoded data
1125     * @since 2.3.1
1126     */
1127    public static byte[] decode( byte[] source )
1128    throws java.io.IOException {
1129        byte[] decoded = null;
1130//        try {
1131            decoded = decode( source, 0, source.length, Base64.NO_OPTIONS );
1132//        } catch( java.io.IOException ex ) {
1133//            assert false : "IOExceptions only come from GZipping, which is turned off: " + ex.getMessage();
1134//        }
1135        return decoded;
1136    }
1137
1138    
1139    
1140    /**
1141     * Low-level access to decoding ASCII characters in
1142     * the form of a byte array. <strong>Ignores GUNZIP option, if
1143     * it's set.</strong> This is not generally a recommended method,
1144     * although it is used internally as part of the decoding process.
1145     * Special case: if len = 0, an empty array is returned. Still,
1146     * if you need more speed and reduced memory footprint (and aren't
1147     * gzipping), consider this method.
1148     *
1149     * @param source The Base64 encoded data
1150     * @param off    The offset of where to begin decoding
1151     * @param len    The length of characters to decode
1152     * @param options Can specify options such as alphabet type to use
1153     * @return decoded data
1154     * @throws java.io.IOException If bogus characters exist in source data
1155     * @since 1.3
1156     */
1157    public static byte[] decode( byte[] source, int off, int len, int options )
1158    throws java.io.IOException {
1159        
1160        // Lots of error checking and exception throwing
1161        if( source == null ){
1162            throw new NullPointerException( "Cannot decode null source array." );
1163        }   // end if
1164        if( off < 0 || off + len > source.length ){
1165            throw new IllegalArgumentException( String.format(
1166            "Source array with length %d cannot have offset of %d and process %d bytes.", source.length, off, len ) );
1167        }   // end if
1168        
1169        if( len == 0 ){
1170            return new byte[0];
1171        }else if( len < 4 ){
1172            throw new IllegalArgumentException( 
1173            "Base64-encoded string must have at least four characters, but length specified was " + len );
1174        }   // end if
1175        
1176        byte[] DECODABET = getDecodabet( options );
1177        
1178        int    len34   = len * 3 / 4;       // Estimate on array size
1179        byte[] outBuff = new byte[ len34 ]; // Upper limit on size of output
1180        int    outBuffPosn = 0;             // Keep track of where we're writing
1181        
1182        byte[] b4        = new byte[4];     // Four byte buffer from source, eliminating white space
1183        int    b4Posn    = 0;               // Keep track of four byte input buffer
1184        int    i         = 0;               // Source array counter
1185        byte   sbiDecode = 0;               // Special value from DECODABET
1186        
1187        for( i = off; i < off+len; i++ ) {  // Loop through source
1188            
1189            sbiDecode = DECODABET[ source[i]&0xFF ];
1190            
1191            // White space, Equals sign, or legit Base64 character
1192            // Note the values such as -5 and -9 in the
1193            // DECODABETs at the top of the file.
1194            if( sbiDecode >= WHITE_SPACE_ENC )  {
1195                if( sbiDecode >= EQUALS_SIGN_ENC ) {
1196                    b4[ b4Posn++ ] = source[i];         // Save non-whitespace
1197                    if( b4Posn > 3 ) {                  // Time to decode?
1198                        outBuffPosn += decode4to3( b4, 0, outBuff, outBuffPosn, options );
1199                        b4Posn = 0;
1200                        
1201                        // If that was the equals sign, break out of 'for' loop
1202                        if( source[i] == EQUALS_SIGN ) {
1203                            break;
1204                        }   // end if: equals sign
1205                    }   // end if: quartet built
1206                }   // end if: equals sign or better
1207            }   // end if: white space, equals sign or better
1208            else {
1209                // There's a bad input character in the Base64 stream.
1210                throw new java.io.IOException( String.format(
1211                "Bad Base64 input character decimal %d in array position %d", ((int)source[i])&0xFF, i ) );
1212            }   // end else: 
1213        }   // each input character
1214                                   
1215        byte[] out = new byte[ outBuffPosn ];
1216        System.arraycopy( outBuff, 0, out, 0, outBuffPosn ); 
1217        return out;
1218    }   // end decode
1219    
1220    
1221        
1222        
1223    /**
1224     * Decodes data from Base64 notation, automatically
1225     * detecting gzip-compressed data and decompressing it.
1226     *
1227     * @param s the string to decode
1228     * @return the decoded data
1229     * @throws java.io.IOException If there is a problem
1230     * @since 1.4
1231     */
1232    public static byte[] decode( String s ) throws java.io.IOException {
1233        return decode( s, NO_OPTIONS );
1234    }
1235
1236    
1237    
1238    /**
1239     * Decodes data from Base64 notation, automatically
1240     * detecting gzip-compressed data and decompressing it.
1241     *
1242     * @param s the string to decode
1243     * @param options encode options such as URL_SAFE
1244     * @return the decoded data
1245     * @throws java.io.IOException if there is an error
1246     * @throws NullPointerException if <code>s</code> is null
1247     * @since 1.4
1248     */
1249    public static byte[] decode( String s, int options ) throws java.io.IOException {
1250        
1251        if( s == null ){
1252            throw new NullPointerException( "Input string was null." );
1253        }   // end if
1254        
1255        byte[] bytes;
1256        try {
1257            bytes = s.getBytes( PREFERRED_ENCODING );
1258        }   // end try
1259        catch( java.io.UnsupportedEncodingException uee ) {
1260            bytes = s.getBytes();
1261        }   // end catch
1262                //</change>
1263        
1264        // Decode
1265        bytes = decode( bytes, 0, bytes.length, options );
1266        
1267        // Check to see if it's gzip-compressed
1268        // GZIP Magic Two-Byte Number: 0x8b1f (35615)
1269        boolean dontGunzip = (options & DONT_GUNZIP) != 0;
1270        if( (bytes != null) && (bytes.length >= 4) && (!dontGunzip) ) {
1271            
1272            int head = ((int)bytes[0] & 0xff) | ((bytes[1] << 8) & 0xff00);
1273            if( java.util.zip.GZIPInputStream.GZIP_MAGIC == head )  {
1274                java.io.ByteArrayInputStream  bais = null;
1275                java.util.zip.GZIPInputStream gzis = null;
1276                java.io.ByteArrayOutputStream baos = null;
1277                byte[] buffer = new byte[2048];
1278                int    length = 0;
1279
1280                try {
1281                    baos = new java.io.ByteArrayOutputStream();
1282                    bais = new java.io.ByteArrayInputStream( bytes );
1283                    gzis = new java.util.zip.GZIPInputStream( bais );
1284
1285                    while( ( length = gzis.read( buffer ) ) >= 0 ) {
1286                        baos.write(buffer,0,length);
1287                    }   // end while: reading input
1288
1289                    // No error? Get new bytes.
1290                    bytes = baos.toByteArray();
1291
1292                }   // end try
1293                catch( java.io.IOException e ) {
1294                    e.printStackTrace();
1295                    // Just return originally-decoded bytes
1296                }   // end catch
1297                finally {
1298                    try{ baos.close(); } catch( Exception e ){}
1299                    try{ gzis.close(); } catch( Exception e ){}
1300                    try{ bais.close(); } catch( Exception e ){}
1301                }   // end finally
1302
1303            }   // end if: gzipped
1304        }   // end if: bytes.length >= 2
1305        
1306        return bytes;
1307    }   // end decode
1308
1309
1310
1311    /**
1312     * Attempts to decode Base64 data and deserialize a Java
1313     * Object within. Returns <code>null</code> if there was an error.
1314     *
1315     * @param encodedObject The Base64 data to decode
1316     * @return The decoded and deserialized object
1317     * @throws NullPointerException if encodedObject is null
1318     * @throws java.io.IOException if there is a general error
1319     * @throws ClassNotFoundException if the decoded object is of a
1320     *         class that cannot be found by the JVM
1321     * @since 1.5
1322     */
1323    public static Object decodeToObject( String encodedObject )
1324    throws java.io.IOException, ClassNotFoundException {
1325        return decodeToObject(encodedObject,NO_OPTIONS,null);
1326    }
1327    
1328
1329    /**
1330     * Attempts to decode Base64 data and deserialize a Java
1331     * Object within. Returns <code>null</code> if there was an error.
1332     * If <code>loader</code> is not null, it will be the class loader
1333     * used when deserializing.
1334     *
1335     * @param encodedObject The Base64 data to decode
1336     * @param options Various parameters related to decoding
1337     * @param loader Optional class loader to use in deserializing classes.
1338     * @return The decoded and deserialized object
1339     * @throws NullPointerException if encodedObject is null
1340     * @throws java.io.IOException if there is a general error
1341     * @throws ClassNotFoundException if the decoded object is of a 
1342     *         class that cannot be found by the JVM
1343     * @since 2.3.4
1344     */
1345    public static Object decodeToObject( 
1346    String encodedObject, int options, final ClassLoader loader )
1347    throws java.io.IOException, ClassNotFoundException {
1348        
1349        // Decode and gunzip if necessary
1350        byte[] objBytes = decode( encodedObject, options );
1351        
1352        java.io.ByteArrayInputStream  bais = null;
1353        java.io.ObjectInputStream     ois  = null;
1354        Object obj = null;
1355        
1356        try {
1357            bais = new java.io.ByteArrayInputStream( objBytes );
1358
1359            // If no custom class loader is provided, use Java's builtin OIS.
1360            if( loader == null ){
1361                ois  = new java.io.ObjectInputStream( bais );
1362            }   // end if: no loader provided
1363
1364            // Else make a customized object input stream that uses
1365            // the provided class loader.
1366            else {
1367                ois = new java.io.ObjectInputStream(bais){
1368                    @Override
1369                    public Class<?> resolveClass(java.io.ObjectStreamClass streamClass)
1370                    throws java.io.IOException, ClassNotFoundException {
1371                        Class<?> c = Class.forName(streamClass.getName(), false, loader);
1372                        if( c == null ){
1373                            return super.resolveClass(streamClass);
1374                        } else {
1375                            return c;   // Class loader knows of this class.
1376                        }   // end else: not null
1377                    }   // end resolveClass
1378                };  // end ois
1379            }   // end else: no custom class loader
1380        
1381            obj = ois.readObject();
1382        }   // end try
1383        catch( java.io.IOException e ) {
1384            throw e;    // Catch and throw in order to execute finally{}
1385        }   // end catch
1386        catch( ClassNotFoundException e ) {
1387            throw e;    // Catch and throw in order to execute finally{}
1388        }   // end catch
1389        finally {
1390            try{ bais.close(); } catch( Exception e ){}
1391            try{ ois.close();  } catch( Exception e ){}
1392        }   // end finally
1393        
1394        return obj;
1395    }   // end decodeObject
1396    
1397    
1398    
1399    /**
1400     * Convenience method for encoding data to a file.
1401     *
1402     * <p>As of v 2.3, if there is a error,
1403     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
1404     * In earlier versions, it just returned false, but
1405     * in retrospect that's a pretty poor way to handle it.</p>
1406     * 
1407     * @param dataToEncode byte array of data to encode in base64 form
1408     * @param filename Filename for saving encoded data
1409     * @throws java.io.IOException if there is an error
1410     * @throws NullPointerException if dataToEncode is null
1411     * @since 2.1
1412     */
1413    public static void encodeToFile( byte[] dataToEncode, String filename )
1414    throws java.io.IOException {
1415        
1416        if( dataToEncode == null ){
1417            throw new NullPointerException( "Data to encode was null." );
1418        }   // end iff
1419        
1420        OutputStream bos = null;
1421        try {
1422            bos = new OutputStream(
1423                  new java.io.FileOutputStream( filename ), Base64.ENCODE );
1424            bos.write( dataToEncode );
1425        }   // end try
1426        catch( java.io.IOException e ) {
1427            throw e; // Catch and throw to execute finally{} block
1428        }   // end catch: java.io.IOException
1429        finally {
1430            try{ bos.close(); } catch( Exception e ){}
1431        }   // end finally
1432        
1433    }   // end encodeToFile
1434    
1435    
1436    /**
1437     * Convenience method for decoding data to a file.
1438     *
1439     * <p>As of v 2.3, if there is a error,
1440     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
1441     * In earlier versions, it just returned false, but
1442     * in retrospect that's a pretty poor way to handle it.</p>
1443     * 
1444     * @param dataToDecode Base64-encoded data as a string
1445     * @param filename Filename for saving decoded data
1446     * @throws java.io.IOException if there is an error
1447     * @since 2.1
1448     */
1449    public static void decodeToFile( String dataToDecode, String filename )
1450    throws java.io.IOException {
1451        
1452        OutputStream bos = null;
1453        try{
1454            bos = new OutputStream(
1455                      new java.io.FileOutputStream( filename ), Base64.DECODE );
1456            bos.write( dataToDecode.getBytes( PREFERRED_ENCODING ) );
1457        }   // end try
1458        catch( java.io.IOException e ) {
1459            throw e; // Catch and throw to execute finally{} block
1460        }   // end catch: java.io.IOException
1461        finally {
1462                try{ bos.close(); } catch( Exception e ){}
1463        }   // end finally
1464        
1465    }   // end decodeToFile
1466    
1467    
1468    
1469    
1470    /**
1471     * Convenience method for reading a base64-encoded
1472     * file and decoding it.
1473     *
1474     * <p>As of v 2.3, if there is a error,
1475     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
1476     * In earlier versions, it just returned false, but
1477     * in retrospect that's a pretty poor way to handle it.</p>
1478     * 
1479     * @param filename Filename for reading encoded data
1480     * @return decoded byte array
1481     * @throws java.io.IOException if there is an error
1482     * @since 2.1
1483     */
1484    public static byte[] decodeFromFile( String filename )
1485    throws java.io.IOException {
1486        
1487        byte[] decodedData = null;
1488        InputStream bis = null;
1489        try
1490        {
1491            // Set up some useful variables
1492            java.io.File file = new java.io.File( filename );
1493            byte[] buffer = null;
1494            int length   = 0;
1495            int numBytes = 0;
1496            
1497            // Check for size of file
1498            if( file.length() > Integer.MAX_VALUE )
1499            {
1500                throw new java.io.IOException( "File is too big for this convenience method (" + file.length() + " bytes)." );
1501            }   // end if: file too big for int index
1502            buffer = new byte[ (int)file.length() ];
1503            
1504            // Open a stream
1505            bis = new InputStream(
1506                      new java.io.BufferedInputStream( 
1507                      new java.io.FileInputStream( file ) ), Base64.DECODE );
1508            
1509            // Read until done
1510            while( ( numBytes = bis.read( buffer, length, 4096 ) ) >= 0 ) {
1511                length += numBytes;
1512            }   // end while
1513            
1514            // Save in a variable to return
1515            decodedData = new byte[ length ];
1516            System.arraycopy( buffer, 0, decodedData, 0, length );
1517            
1518        }   // end try
1519        catch( java.io.IOException e ) {
1520            throw e; // Catch and release to execute finally{}
1521        }   // end catch: java.io.IOException
1522        finally {
1523            try{ bis.close(); } catch( Exception e) {}
1524        }   // end finally
1525        
1526        return decodedData;
1527    }   // end decodeFromFile
1528    
1529    
1530    
1531    /**
1532     * Convenience method for reading a binary file
1533     * and base64-encoding it.
1534     *
1535     * <p>As of v 2.3, if there is a error,
1536     * the method will throw an java.io.IOException. <b>This is new to v2.3!</b>
1537     * In earlier versions, it just returned false, but
1538     * in retrospect that's a pretty poor way to handle it.</p>
1539     * 
1540     * @param filename Filename for reading binary data
1541     * @return base64-encoded string
1542     * @throws java.io.IOException if there is an error
1543     * @since 2.1
1544     */
1545    public static String encodeFromFile( String filename )
1546    throws java.io.IOException {
1547        
1548        String encodedData = null;
1549        InputStream bis = null;
1550        try
1551        {
1552            // Set up some useful variables
1553            java.io.File file = new java.io.File( filename );
1554            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)
1555            int length   = 0;
1556            int numBytes = 0;
1557            
1558            // Open a stream
1559            bis = new InputStream(
1560                      new java.io.BufferedInputStream( 
1561                      new java.io.FileInputStream( file ) ), Base64.ENCODE );
1562            
1563            // Read until done
1564            while( ( numBytes = bis.read( buffer, length, 4096 ) ) >= 0 ) {
1565                length += numBytes;
1566            }   // end while
1567            
1568            // Save in a variable to return
1569            encodedData = new String( buffer, 0, length, Base64.PREFERRED_ENCODING );
1570                
1571        }   // end try
1572        catch( java.io.IOException e ) {
1573            throw e; // Catch and release to execute finally{}
1574        }   // end catch: java.io.IOException
1575        finally {
1576            try{ bis.close(); } catch( Exception e) {}
1577        }   // end finally
1578        
1579        return encodedData;
1580        }   // end encodeFromFile
1581    
1582    /**
1583     * Reads <code>infile</code> and encodes it to <code>outfile</code>.
1584     *
1585     * @param infile Input file
1586     * @param outfile Output file
1587     * @throws java.io.IOException if there is an error
1588     * @since 2.2
1589     */
1590    public static void encodeFileToFile( String infile, String outfile )
1591    throws java.io.IOException {
1592        
1593        String encoded = Base64.encodeFromFile( infile );
1594        java.io.OutputStream out = null;
1595        try{
1596            out = new java.io.BufferedOutputStream(
1597                  new java.io.FileOutputStream( outfile ) );
1598            out.write( encoded.getBytes("US-ASCII") ); // Strict, 7-bit output.
1599        }   // end try
1600        catch( java.io.IOException e ) {
1601            throw e; // Catch and release to execute finally{}
1602        }   // end catch
1603        finally {
1604            try { out.close(); }
1605            catch( Exception ex ){}
1606        }   // end finally    
1607    }   // end encodeFileToFile
1608
1609
1610    /**
1611     * Reads <code>infile</code> and decodes it to <code>outfile</code>.
1612     *
1613     * @param infile Input file
1614     * @param outfile Output file
1615     * @throws java.io.IOException if there is an error
1616     * @since 2.2
1617     */
1618    public static void decodeFileToFile( String infile, String outfile )
1619    throws java.io.IOException {
1620        
1621        byte[] decoded = Base64.decodeFromFile( infile );
1622        java.io.OutputStream out = null;
1623        try{
1624            out = new java.io.BufferedOutputStream(
1625                  new java.io.FileOutputStream( outfile ) );
1626            out.write( decoded );
1627        }   // end try
1628        catch( java.io.IOException e ) {
1629            throw e; // Catch and release to execute finally{}
1630        }   // end catch
1631        finally {
1632            try { out.close(); }
1633            catch( Exception ex ){}
1634        }   // end finally    
1635    }   // end decodeFileToFile
1636    
1637    
1638    /* ********  I N N E R   C L A S S   I N P U T S T R E A M  ******** */
1639    
1640    
1641    
1642    /**
1643     * A {@link Base64.InputStream} will read data from another
1644     * <code>java.io.InputStream</code>, given in the constructor,
1645     * and encode/decode to/from Base64 notation on the fly.
1646     *
1647     * @see Base64
1648     * @since 1.3
1649     */
1650    public static class InputStream extends java.io.FilterInputStream {
1651        
1652        private boolean encode;         // Encoding or decoding
1653        private int     position;       // Current position in the buffer
1654        private byte[]  buffer;         // Small buffer holding converted data
1655        private int     bufferLength;   // Length of buffer (3 or 4)
1656        private int     numSigBytes;    // Number of meaningful bytes in the buffer
1657        private int     lineLength;
1658        private boolean breakLines;     // Break lines at less than 80 characters
1659        private int     options;        // Record options used to create the stream.
1660        private byte[]  decodabet;      // Local copies to avoid extra method calls
1661        
1662        
1663        /**
1664         * Constructs a {@link Base64.InputStream} in DECODE mode.
1665         *
1666         * @param in the <code>java.io.InputStream</code> from which to read data.
1667         * @since 1.3
1668         */
1669        public InputStream( java.io.InputStream in ) {
1670            this( in, DECODE );
1671        }   // end constructor
1672        
1673        
1674        /**
1675         * Constructs a {@link Base64.InputStream} in
1676         * either ENCODE or DECODE mode.
1677         * <p>
1678         * Valid options:<pre>
1679         *   ENCODE or DECODE: Encode or Decode as data is read.
1680         *   DO_BREAK_LINES: break lines at 76 characters
1681         *     (only meaningful when encoding)
1682         * </pre>
1683         * <p>
1684         * Example: <code>new Base64.InputStream( in, Base64.DECODE )</code>
1685         *
1686         *
1687         * @param in the <code>java.io.InputStream</code> from which to read data.
1688         * @param options Specified options
1689         * @see Base64#ENCODE
1690         * @see Base64#DECODE
1691         * @see Base64#DO_BREAK_LINES
1692         * @since 2.0
1693         */
1694        public InputStream( java.io.InputStream in, int options ) {
1695            
1696            super( in );
1697            this.options      = options; // Record for later
1698            this.breakLines   = (options & DO_BREAK_LINES) > 0;
1699            this.encode       = (options & ENCODE) > 0;
1700            this.bufferLength = encode ? 4 : 3;
1701            this.buffer       = new byte[ bufferLength ];
1702            this.position     = -1;
1703            this.lineLength   = 0;
1704            this.decodabet    = getDecodabet(options);
1705        }   // end constructor
1706        
1707        /**
1708         * Reads enough of the input stream to convert
1709         * to/from Base64 and returns the next byte.
1710         *
1711         * @return next byte
1712         * @since 1.3
1713         */
1714        @Override
1715        public int read() throws java.io.IOException  {
1716            
1717            // Do we need to get data?
1718            if( position < 0 ) {
1719                if( encode ) {
1720                    byte[] b3 = new byte[3];
1721                    int numBinaryBytes = 0;
1722                    for( int i = 0; i < 3; i++ ) {
1723                        int b = in.read();
1724
1725                        // If end of stream, b is -1.
1726                        if( b >= 0 ) {
1727                            b3[i] = (byte)b;
1728                            numBinaryBytes++;
1729                        } else {
1730                            break; // out of for loop
1731                        }   // end else: end of stream
1732                            
1733                    }   // end for: each needed input byte
1734                    
1735                    if( numBinaryBytes > 0 ) {
1736                        encode3to4( b3, 0, numBinaryBytes, buffer, 0, options );
1737                        position = 0;
1738                        numSigBytes = 4;
1739                    }   // end if: got data
1740                    else {
1741                        return -1;  // Must be end of stream
1742                    }   // end else
1743                }   // end if: encoding
1744                
1745                // Else decoding
1746                else {
1747                    byte[] b4 = new byte[4];
1748                    int i = 0;
1749                    for( i = 0; i < 4; i++ ) {
1750                        // Read four "meaningful" bytes:
1751                        int b = 0;
1752                        do{ b = in.read(); }
1753                        while( b >= 0 && decodabet[ b & 0x7f ] <= WHITE_SPACE_ENC );
1754                        
1755                        if( b < 0 ) {
1756                            break; // Reads a -1 if end of stream
1757                        }   // end if: end of stream
1758                        
1759                        b4[i] = (byte)b;
1760                    }   // end for: each needed input byte
1761                    
1762                    if( i == 4 ) {
1763                        numSigBytes = decode4to3( b4, 0, buffer, 0, options );
1764                        position = 0;
1765                    }   // end if: got four characters
1766                    else if( i == 0 ){
1767                        return -1;
1768                    }   // end else if: also padded correctly
1769                    else {
1770                        // Must have broken out from above.
1771                        throw new java.io.IOException( "Improperly padded Base64 input." );
1772                    }   // end 
1773                    
1774                }   // end else: decode
1775            }   // end else: get data
1776            
1777            // Got data?
1778            if( position >= 0 ) {
1779                // End of relevant data?
1780                if( /*!encode &&*/ position >= numSigBytes ){
1781                    return -1;
1782                }   // end if: got data
1783                
1784                if( encode && breakLines && lineLength >= MAX_LINE_LENGTH ) {
1785                    lineLength = 0;
1786                    return '\n';
1787                }   // end if
1788                else {
1789                    lineLength++;   // This isn't important when decoding
1790                                    // but throwing an extra "if" seems
1791                                    // just as wasteful.
1792                    
1793                    int b = buffer[ position++ ];
1794
1795                    if( position >= bufferLength ) {
1796                        position = -1;
1797                    }   // end if: end
1798
1799                    return b & 0xFF; // This is how you "cast" a byte that's
1800                                     // intended to be unsigned.
1801                }   // end else
1802            }   // end if: position >= 0
1803            
1804            // Else error
1805            else {
1806                throw new java.io.IOException( "Error in Base64 code reading stream." );
1807            }   // end else
1808        }   // end read
1809        
1810        
1811        /**
1812         * Calls {@link #read()} repeatedly until the end of stream
1813         * is reached or <var>len</var> bytes are read.
1814         * Returns number of bytes read into array or -1 if
1815         * end of stream is encountered.
1816         *
1817         * @param dest array to hold values
1818         * @param off offset for array
1819         * @param len max number of bytes to read into array
1820         * @return bytes read into array or -1 if end of stream is encountered.
1821         * @since 1.3
1822         */
1823        @Override
1824        public int read( byte[] dest, int off, int len ) 
1825        throws java.io.IOException {
1826            int i;
1827            int b;
1828            for( i = 0; i < len; i++ ) {
1829                b = read();
1830                
1831                if( b >= 0 ) {
1832                    dest[off + i] = (byte) b;
1833                }
1834                else if( i == 0 ) {
1835                    return -1;
1836                }
1837                else {
1838                    break; // Out of 'for' loop
1839                } // Out of 'for' loop
1840            }   // end for: each byte read
1841            return i;
1842        }   // end read
1843        
1844    }   // end inner class InputStream
1845    
1846    
1847    
1848    
1849    
1850    
1851    /* ********  I N N E R   C L A S S   O U T P U T S T R E A M  ******** */
1852    
1853    
1854    
1855    /**
1856     * A {@link Base64.OutputStream} will write data to another
1857     * <code>java.io.OutputStream</code>, given in the constructor,
1858     * and encode/decode to/from Base64 notation on the fly.
1859     *
1860     * @see Base64
1861     * @since 1.3
1862     */
1863    public static class OutputStream extends java.io.FilterOutputStream {
1864        
1865        private boolean encode;
1866        private int     position;
1867        private byte[]  buffer;
1868        private int     bufferLength;
1869        private int     lineLength;
1870        private boolean breakLines;
1871        private byte[]  b4;         // Scratch used in a few places
1872        private boolean suspendEncoding;
1873        private int     options;    // Record for later
1874        private byte[]  decodabet;  // Local copies to avoid extra method calls
1875        
1876        /**
1877         * Constructs a {@link Base64.OutputStream} in ENCODE mode.
1878         *
1879         * @param out the <code>java.io.OutputStream</code> to which data will be written.
1880         * @since 1.3
1881         */
1882        public OutputStream( java.io.OutputStream out ) {
1883            this( out, ENCODE );
1884        }   // end constructor
1885        
1886        
1887        /**
1888         * Constructs a {@link Base64.OutputStream} in
1889         * either ENCODE or DECODE mode.
1890         * <p>
1891         * Valid options:<pre>
1892         *   ENCODE or DECODE: Encode or Decode as data is read.
1893         *   DO_BREAK_LINES: don't break lines at 76 characters
1894         *     (only meaningful when encoding)
1895         * </pre>
1896         * <p>
1897         * Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>
1898         *
1899         * @param out the <code>java.io.OutputStream</code> to which data will be written.
1900         * @param options Specified options.
1901         * @see Base64#ENCODE
1902         * @see Base64#DECODE
1903         * @see Base64#DO_BREAK_LINES
1904         * @since 1.3
1905         */
1906        public OutputStream( java.io.OutputStream out, int options ) {
1907            super( out );
1908            this.breakLines   = (options & DO_BREAK_LINES) != 0;
1909            this.encode       = (options & ENCODE) != 0;
1910            this.bufferLength = encode ? 3 : 4;
1911            this.buffer       = new byte[ bufferLength ];
1912            this.position     = 0;
1913            this.lineLength   = 0;
1914            this.suspendEncoding = false;
1915            this.b4           = new byte[4];
1916            this.options      = options;
1917            this.decodabet    = getDecodabet(options);
1918        }   // end constructor
1919        
1920        
1921        /**
1922         * Writes the byte to the output stream after
1923         * converting to/from Base64 notation.
1924         * When encoding, bytes are buffered three
1925         * at a time before the output stream actually
1926         * gets a write() call.
1927         * When decoding, bytes are buffered four
1928         * at a time.
1929         *
1930         * @param theByte the byte to write
1931         * @since 1.3
1932         */
1933        @Override
1934        public void write(int theByte) 
1935        throws java.io.IOException {
1936            // Encoding suspended?
1937            if( suspendEncoding ) {
1938                this.out.write( theByte );
1939                return;
1940            }   // end if: supsended
1941            
1942            // Encode?
1943            if( encode ) {
1944                buffer[ position++ ] = (byte)theByte;
1945                if( position >= bufferLength ) { // Enough to encode.
1946                
1947                    this.out.write( encode3to4( b4, buffer, bufferLength, options ) );
1948
1949                    lineLength += 4;
1950                    if( breakLines && lineLength >= MAX_LINE_LENGTH ) {
1951                        this.out.write( NEW_LINE );
1952                        lineLength = 0;
1953                    }   // end if: end of line
1954
1955                    position = 0;
1956                }   // end if: enough to output
1957            }   // end if: encoding
1958
1959            // Else, Decoding
1960            else {
1961                // Meaningful Base64 character?
1962                if( decodabet[ theByte & 0x7f ] > WHITE_SPACE_ENC ) {
1963                    buffer[ position++ ] = (byte)theByte;
1964                    if( position >= bufferLength ) { // Enough to output.
1965                    
1966                        int len = Base64.decode4to3( buffer, 0, b4, 0, options );
1967                        out.write( b4, 0, len );
1968                        position = 0;
1969                    }   // end if: enough to output
1970                }   // end if: meaningful base64 character
1971                else if( decodabet[ theByte & 0x7f ] != WHITE_SPACE_ENC ) {
1972                    throw new java.io.IOException( "Invalid character in Base64 data." );
1973                }   // end else: not white space either
1974            }   // end else: decoding
1975        }   // end write
1976        
1977        
1978        
1979        /**
1980         * Calls {@link #write(int)} repeatedly until <var>len</var> 
1981         * bytes are written.
1982         *
1983         * @param theBytes array from which to read bytes
1984         * @param off offset for array
1985         * @param len max number of bytes to read into array
1986         * @since 1.3
1987         */
1988        @Override
1989        public void write( byte[] theBytes, int off, int len ) 
1990        throws java.io.IOException {
1991            // Encoding suspended?
1992            if( suspendEncoding ) {
1993                this.out.write( theBytes, off, len );
1994                return;
1995            }   // end if: supsended
1996            
1997            for( int i = 0; i < len; i++ ) {
1998                write( theBytes[ off + i ] );
1999            }   // end for: each byte written
2000            
2001        }   // end write
2002        
2003        
2004        
2005        /**
2006         * Method added by PHIL. [Thanks, PHIL. -Rob]
2007         * This pads the buffer without closing the stream.
2008         * @throws java.io.IOException  if there's an error.
2009         */
2010        public void flushBase64() throws java.io.IOException  {
2011            if( position > 0 ) {
2012                if( encode ) {
2013                    out.write( encode3to4( b4, buffer, position, options ) );
2014                    position = 0;
2015                }   // end if: encoding
2016                else {
2017                    throw new java.io.IOException( "Base64 input not properly padded." );
2018                }   // end else: decoding
2019            }   // end if: buffer partially full
2020
2021        }   // end flush
2022
2023        
2024        /** 
2025         * Flushes and closes (I think, in the superclass) the stream. 
2026         *
2027         * @since 1.3
2028         */
2029        @Override
2030        public void close() throws java.io.IOException {
2031            // 1. Ensure that pending characters are written
2032            flushBase64();
2033
2034            // 2. Actually close the stream
2035            // Base class both flushes and closes.
2036            super.close();
2037            
2038            buffer = null;
2039            out    = null;
2040        }   // end close
2041        
2042        
2043        
2044        /**
2045         * Suspends encoding of the stream.
2046         * May be helpful if you need to embed a piece of
2047         * base64-encoded data in a stream.
2048         *
2049         * @throws java.io.IOException  if there's an error flushing
2050         * @since 1.5.1
2051         */
2052        public void suspendEncoding() throws java.io.IOException  {
2053            flushBase64();
2054            this.suspendEncoding = true;
2055        }   // end suspendEncoding
2056        
2057        
2058        /**
2059         * Resumes encoding of the stream.
2060         * May be helpful if you need to embed a piece of
2061         * base64-encoded data in a stream.
2062         *
2063         * @since 1.5.1
2064         */
2065        public void resumeEncoding() {
2066            this.suspendEncoding = false;
2067        }   // end resumeEncoding
2068        
2069        
2070        
2071    }   // end inner class OutputStream
2072    
2073    
2074}   // end class Base64