1 | package nu.fw.jeti.util; |
---|
2 | |
---|
3 | /** |
---|
4 | * Encodes and decodes to and from Base64 notation. |
---|
5 | * |
---|
6 | * <p> |
---|
7 | * Change Log: |
---|
8 | * </p> |
---|
9 | * <ul> |
---|
10 | * <li>v2.1 - Cleaned up javadoc comments and unused variables and methods. Added |
---|
11 | * some convenience methods for reading and writing to and from files.</li> |
---|
12 | * <li>v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems |
---|
13 | * with other encodings (like EBCDIC).</li> |
---|
14 | * <li>v2.0.1 - Fixed an error when decoding a single byte, that is, when the |
---|
15 | * encoded data was a single byte.</li> |
---|
16 | * <li>v2.0 - I got rid of methods that used booleans to set options. |
---|
17 | * Now everything is more consolidated and cleaner. The code now detects |
---|
18 | * when data that's being decoded is gzip-compressed and will decompress it |
---|
19 | * automatically. Generally things are cleaner. You'll probably have to |
---|
20 | * change some method calls that you were making to support the new |
---|
21 | * options format (<tt>int</tt>s that you "OR" together).</li> |
---|
22 | * <li>v1.5.1 - Fixed bug when decompressing and decoding to a |
---|
23 | * byte[] using <tt>decode( String s, boolean gzipCompressed )</tt>. |
---|
24 | * Added the ability to "suspend" encoding in the Output Stream so |
---|
25 | * you can turn on and off the encoding if you need to embed base64 |
---|
26 | * data in an otherwise "normal" stream (like an XML file).</li> |
---|
27 | * <li>v1.5 - Output stream pases on flush() command but doesn't do anything itself. |
---|
28 | * This helps when using GZIP streams. |
---|
29 | * Added the ability to GZip-compress objects before encoding them.</li> |
---|
30 | * <li>v1.4 - Added helper methods to read/write files.</li> |
---|
31 | * <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li> |
---|
32 | * <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream |
---|
33 | * where last buffer being read, if not completely full, was not returned.</li> |
---|
34 | * <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.</li> |
---|
35 | * <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li> |
---|
36 | * </ul> |
---|
37 | * |
---|
38 | * <p> |
---|
39 | * I am placing this code in the Public Domain. Do with it as you will. |
---|
40 | * This software comes with no guarantees or warranties but with |
---|
41 | * plenty of well-wishing instead! |
---|
42 | * Please visit <a href="http://iharder.net/base64">http://iharder.net/base64</a> |
---|
43 | * periodically to check for updates or to contribute improvements. |
---|
44 | * </p> |
---|
45 | * |
---|
46 | * @author Robert Harder |
---|
47 | * @author rob@iharder.net |
---|
48 | * @version 2.1 |
---|
49 | */ |
---|
50 | public class Base64 |
---|
51 | { |
---|
52 | |
---|
53 | /* ******** P U B L I C F I E L D S ******** */ |
---|
54 | |
---|
55 | |
---|
56 | /** No options specified. Value is zero. */ |
---|
57 | public final static int NO_OPTIONS = 0; |
---|
58 | |
---|
59 | /** Specify encoding. */ |
---|
60 | public final static int ENCODE = 1; |
---|
61 | |
---|
62 | |
---|
63 | /** Specify decoding. */ |
---|
64 | public final static int DECODE = 0; |
---|
65 | |
---|
66 | |
---|
67 | /** Specify that data should be gzip-compressed. */ |
---|
68 | public final static int GZIP = 2; |
---|
69 | |
---|
70 | |
---|
71 | /** Don't break lines when encoding (violates strict Base64 specification) */ |
---|
72 | public final static int DONT_BREAK_LINES = 8; |
---|
73 | |
---|
74 | |
---|
75 | /* ******** P R I V A T E F I E L D S ******** */ |
---|
76 | |
---|
77 | |
---|
78 | /** Maximum line length (76) of Base64 output. */ |
---|
79 | private final static int MAX_LINE_LENGTH = 76; |
---|
80 | |
---|
81 | |
---|
82 | /** The equals sign (=) as a byte. */ |
---|
83 | private final static byte EQUALS_SIGN = (byte)'='; |
---|
84 | |
---|
85 | |
---|
86 | /** The new line character (\n) as a byte. */ |
---|
87 | private final static byte NEW_LINE = (byte)'\n'; |
---|
88 | |
---|
89 | |
---|
90 | /** Preferred encoding. */ |
---|
91 | private final static String PREFERRED_ENCODING = "UTF-8"; |
---|
92 | |
---|
93 | |
---|
94 | /** The 64 valid Base64 values. */ |
---|
95 | private final static byte[] ALPHABET; |
---|
96 | private final static byte[] _NATIVE_ALPHABET = /* May be something funny like EBCDIC */ |
---|
97 | { |
---|
98 | (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G', |
---|
99 | (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N', |
---|
100 | (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', |
---|
101 | (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z', |
---|
102 | (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g', |
---|
103 | (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n', |
---|
104 | (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', |
---|
105 | (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z', |
---|
106 | (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', |
---|
107 | (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/' |
---|
108 | }; |
---|
109 | |
---|
110 | /** Determine which ALPHABET to use. */ |
---|
111 | static |
---|
112 | { |
---|
113 | byte[] __bytes; |
---|
114 | try |
---|
115 | { |
---|
116 | __bytes = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".getBytes( PREFERRED_ENCODING ); |
---|
117 | } // end try |
---|
118 | catch (java.io.UnsupportedEncodingException use) |
---|
119 | { |
---|
120 | __bytes = _NATIVE_ALPHABET; // Fall back to native encoding |
---|
121 | } // end catch |
---|
122 | ALPHABET = __bytes; |
---|
123 | } // end static |
---|
124 | |
---|
125 | |
---|
126 | /** |
---|
127 | * Translates a Base64 value to either its 6-bit reconstruction value |
---|
128 | * or a negative number indicating some other meaning. |
---|
129 | **/ |
---|
130 | private final static byte[] DECODABET = |
---|
131 | { |
---|
132 | -9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 0 - 8 |
---|
133 | -5,-5, // Whitespace: Tab and Linefeed |
---|
134 | -9,-9, // Decimal 11 - 12 |
---|
135 | -5, // Whitespace: Carriage Return |
---|
136 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 14 - 26 |
---|
137 | -9,-9,-9,-9,-9, // Decimal 27 - 31 |
---|
138 | -5, // Whitespace: Space |
---|
139 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 33 - 42 |
---|
140 | 62, // Plus sign at decimal 43 |
---|
141 | -9,-9,-9, // Decimal 44 - 46 |
---|
142 | 63, // Slash at decimal 47 |
---|
143 | 52,53,54,55,56,57,58,59,60,61, // Numbers zero through nine |
---|
144 | -9,-9,-9, // Decimal 58 - 60 |
---|
145 | -1, // Equals sign at decimal 61 |
---|
146 | -9,-9,-9, // Decimal 62 - 64 |
---|
147 | 0,1,2,3,4,5,6,7,8,9,10,11,12,13, // Letters 'A' through 'N' |
---|
148 | 14,15,16,17,18,19,20,21,22,23,24,25, // Letters 'O' through 'Z' |
---|
149 | -9,-9,-9,-9,-9,-9, // Decimal 91 - 96 |
---|
150 | 26,27,28,29,30,31,32,33,34,35,36,37,38, // Letters 'a' through 'm' |
---|
151 | 39,40,41,42,43,44,45,46,47,48,49,50,51, // Letters 'n' through 'z' |
---|
152 | -9,-9,-9,-9 // Decimal 123 - 126 |
---|
153 | /*,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 127 - 139 |
---|
154 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 140 - 152 |
---|
155 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 153 - 165 |
---|
156 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 166 - 178 |
---|
157 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 179 - 191 |
---|
158 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 192 - 204 |
---|
159 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 205 - 217 |
---|
160 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 218 - 230 |
---|
161 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 231 - 243 |
---|
162 | -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9 // Decimal 244 - 255 */ |
---|
163 | }; |
---|
164 | |
---|
165 | // I think I end up not using the BAD_ENCODING indicator. |
---|
166 | //private final static byte BAD_ENCODING = -9; // Indicates error in encoding |
---|
167 | private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding |
---|
168 | private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding |
---|
169 | |
---|
170 | |
---|
171 | /** Defeats instantiation. */ |
---|
172 | private Base64(){} |
---|
173 | |
---|
174 | |
---|
175 | |
---|
176 | /* ******** E N C O D I N G M E T H O D S ******** */ |
---|
177 | |
---|
178 | |
---|
179 | |
---|
180 | |
---|
181 | /** |
---|
182 | * Encodes up to three bytes of the array <var>source</var> |
---|
183 | * and writes the resulting four Base64 bytes to <var>destination</var>. |
---|
184 | * The source and destination arrays can be manipulated |
---|
185 | * anywhere along their length by specifying |
---|
186 | * <var>srcOffset</var> and <var>destOffset</var>. |
---|
187 | * This method does not check to make sure your arrays |
---|
188 | * are large enough to accomodate <var>srcOffset</var> + 3 for |
---|
189 | * the <var>source</var> array or <var>destOffset</var> + 4 for |
---|
190 | * the <var>destination</var> array. |
---|
191 | * The actual number of significant bytes in your array is |
---|
192 | * given by <var>numSigBytes</var>. |
---|
193 | * |
---|
194 | * @param source the array to convert |
---|
195 | * @param srcOffset the index where conversion begins |
---|
196 | * @param numSigBytes the number of significant bytes in your array |
---|
197 | * @param destination the array to hold the conversion |
---|
198 | * @param destOffset the index where output will be put |
---|
199 | * @return the <var>destination</var> array |
---|
200 | * @since 1.3 |
---|
201 | */ |
---|
202 | private static byte[] encode3to4( |
---|
203 | byte[] source, int srcOffset, int numSigBytes, |
---|
204 | byte[] destination, int destOffset ) |
---|
205 | { |
---|
206 | // 1 2 3 |
---|
207 | // 01234567890123456789012345678901 Bit position |
---|
208 | // --------000000001111111122222222 Array position from threeBytes |
---|
209 | // --------| || || || | Six bit groups to index ALPHABET |
---|
210 | // >>18 >>12 >> 6 >> 0 Right shift necessary |
---|
211 | // 0x3f 0x3f 0x3f Additional AND |
---|
212 | |
---|
213 | // Create buffer with zero-padding if there are only one or two |
---|
214 | // significant bytes passed in the array. |
---|
215 | // We have to shift left 24 in order to flush out the 1's that appear |
---|
216 | // when Java treats a value as negative that is cast from a byte to an int. |
---|
217 | int inBuff = ( numSigBytes > 0 ? ((source[ srcOffset ] << 24) >>> 8) : 0 ) |
---|
218 | | ( numSigBytes > 1 ? ((source[ srcOffset + 1 ] << 24) >>> 16) : 0 ) |
---|
219 | | ( numSigBytes > 2 ? ((source[ srcOffset + 2 ] << 24) >>> 24) : 0 ); |
---|
220 | |
---|
221 | switch( numSigBytes ) |
---|
222 | { |
---|
223 | case 3: |
---|
224 | destination[ destOffset ] = ALPHABET[ (inBuff >>> 18) ]; |
---|
225 | destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ]; |
---|
226 | destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>> 6) & 0x3f ]; |
---|
227 | destination[ destOffset + 3 ] = ALPHABET[ (inBuff ) & 0x3f ]; |
---|
228 | return destination; |
---|
229 | |
---|
230 | case 2: |
---|
231 | destination[ destOffset ] = ALPHABET[ (inBuff >>> 18) ]; |
---|
232 | destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ]; |
---|
233 | destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>> 6) & 0x3f ]; |
---|
234 | destination[ destOffset + 3 ] = EQUALS_SIGN; |
---|
235 | return destination; |
---|
236 | |
---|
237 | case 1: |
---|
238 | destination[ destOffset ] = ALPHABET[ (inBuff >>> 18) ]; |
---|
239 | destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ]; |
---|
240 | destination[ destOffset + 2 ] = EQUALS_SIGN; |
---|
241 | destination[ destOffset + 3 ] = EQUALS_SIGN; |
---|
242 | return destination; |
---|
243 | |
---|
244 | default: |
---|
245 | return destination; |
---|
246 | } // end switch |
---|
247 | } // end encode3to4 |
---|
248 | |
---|
249 | |
---|
250 | |
---|
251 | /** |
---|
252 | * Encodes a byte array into Base64 notation. |
---|
253 | * Does not GZip-compress data. |
---|
254 | * |
---|
255 | * @param source The data to convert |
---|
256 | * @since 1.4 |
---|
257 | */ |
---|
258 | public static String encodeBytes( byte[] source ) |
---|
259 | { |
---|
260 | return encodeBytes( source, 0, source.length, NO_OPTIONS ); |
---|
261 | } // end encodeBytes |
---|
262 | |
---|
263 | |
---|
264 | |
---|
265 | /** |
---|
266 | * Encodes a byte array into Base64 notation. |
---|
267 | * <p> |
---|
268 | * Valid options:<pre> |
---|
269 | * GZIP: gzip-compresses object before encoding it. |
---|
270 | * DONT_BREAK_LINES: don't break lines at 76 characters |
---|
271 | * <i>Note: Technically, this makes your encoding non-compliant.</i> |
---|
272 | * </pre> |
---|
273 | * <p> |
---|
274 | * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or |
---|
275 | * <p> |
---|
276 | * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code> |
---|
277 | * |
---|
278 | * |
---|
279 | * @param source The data to convert |
---|
280 | * @param options Specified options |
---|
281 | * @see Base64#GZIP |
---|
282 | * @see Base64#DONT_BREAK_LINES |
---|
283 | * @since 2.0 |
---|
284 | */ |
---|
285 | public static String encodeBytes( byte[] source, int options ) |
---|
286 | { |
---|
287 | return encodeBytes( source, 0, source.length, options ); |
---|
288 | } // end encodeBytes |
---|
289 | |
---|
290 | |
---|
291 | /** |
---|
292 | * Encodes a byte array into Base64 notation. |
---|
293 | * Does not GZip-compress data. |
---|
294 | * |
---|
295 | * @param source The data to convert |
---|
296 | * @param off Offset in array where conversion should begin |
---|
297 | * @param len Length of data to convert |
---|
298 | * @since 1.4 |
---|
299 | */ |
---|
300 | public static String encodeBytes( byte[] source, int off, int len ) |
---|
301 | { |
---|
302 | return encodeBytes( source, off, len, NO_OPTIONS ); |
---|
303 | } // end encodeBytes |
---|
304 | |
---|
305 | |
---|
306 | |
---|
307 | /** |
---|
308 | * Encodes a byte array into Base64 notation. |
---|
309 | * <p> |
---|
310 | * Valid options:<pre> |
---|
311 | * GZIP: gzip-compresses object before encoding it. |
---|
312 | * DONT_BREAK_LINES: don't break lines at 76 characters |
---|
313 | * <i>Note: Technically, this makes your encoding non-compliant.</i> |
---|
314 | * </pre> |
---|
315 | * <p> |
---|
316 | * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or |
---|
317 | * <p> |
---|
318 | * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code> |
---|
319 | * |
---|
320 | * |
---|
321 | * @param source The data to convert |
---|
322 | * @param off Offset in array where conversion should begin |
---|
323 | * @param len Length of data to convert |
---|
324 | * @param options Specified options |
---|
325 | * @see Base64#GZIP |
---|
326 | * @see Base64#DONT_BREAK_LINES |
---|
327 | * @since 2.0 |
---|
328 | */ |
---|
329 | public static String encodeBytes( byte[] source, int off, int len, int options ) |
---|
330 | { |
---|
331 | // Isolate options |
---|
332 | int dontBreakLines = ( options & DONT_BREAK_LINES ); |
---|
333 | int gzip = ( options & GZIP ); |
---|
334 | |
---|
335 | // Compress? |
---|
336 | if( gzip == GZIP ) |
---|
337 | { |
---|
338 | /* |
---|
339 | java.io.ByteArrayOutputStream baos = null; |
---|
340 | java.util.zip.GZIPOutputStream gzos = null; |
---|
341 | Base64.OutputStream b64os = null; |
---|
342 | |
---|
343 | |
---|
344 | try |
---|
345 | { |
---|
346 | // GZip -> Base64 -> ByteArray |
---|
347 | baos = new java.io.ByteArrayOutputStream(); |
---|
348 | b64os = new Base64.OutputStream( baos, ENCODE | dontBreakLines ); |
---|
349 | gzos = new java.util.zip.GZIPOutputStream( b64os ); |
---|
350 | |
---|
351 | gzos.write( source, off, len ); |
---|
352 | gzos.close(); |
---|
353 | } // end try |
---|
354 | catch( java.io.IOException e ) |
---|
355 | { |
---|
356 | e.printStackTrace(); |
---|
357 | return null; |
---|
358 | } // end catch |
---|
359 | finally |
---|
360 | { |
---|
361 | try{ gzos.close(); } catch( Exception e ){} |
---|
362 | try{ b64os.close(); } catch( Exception e ){} |
---|
363 | try{ baos.close(); } catch( Exception e ){} |
---|
364 | } // end finally |
---|
365 | |
---|
366 | // Return value according to relevant encoding. |
---|
367 | try |
---|
368 | { |
---|
369 | return new String( baos.toByteArray(), PREFERRED_ENCODING ); |
---|
370 | } // end try |
---|
371 | catch (java.io.UnsupportedEncodingException uue) |
---|
372 | { |
---|
373 | return new String( baos.toByteArray() ); |
---|
374 | } // end catch |
---|
375 | */ |
---|
376 | return null; |
---|
377 | } // end if: compress |
---|
378 | |
---|
379 | // Else, don't compress. Better not to use streams at all then. |
---|
380 | else |
---|
381 | { |
---|
382 | // Convert option to boolean in way that code likes it. |
---|
383 | boolean breakLines = dontBreakLines == 0; |
---|
384 | |
---|
385 | int len43 = len * 4 / 3; |
---|
386 | byte[] outBuff = new byte[ ( len43 ) // Main 4:3 |
---|
387 | + ( (len % 3) > 0 ? 4 : 0 ) // Account for padding |
---|
388 | + (breakLines ? ( len43 / MAX_LINE_LENGTH ) : 0) ]; // New lines |
---|
389 | int d = 0; |
---|
390 | int e = 0; |
---|
391 | int len2 = len - 2; |
---|
392 | int lineLength = 0; |
---|
393 | for( ; d < len2; d+=3, e+=4 ) |
---|
394 | { |
---|
395 | encode3to4( source, d+off, 3, outBuff, e ); |
---|
396 | |
---|
397 | lineLength += 4; |
---|
398 | if( breakLines && lineLength == MAX_LINE_LENGTH ) |
---|
399 | { |
---|
400 | outBuff[e+4] = NEW_LINE; |
---|
401 | e++; |
---|
402 | lineLength = 0; |
---|
403 | } // end if: end of line |
---|
404 | } // en dfor: each piece of array |
---|
405 | |
---|
406 | if( d < len ) |
---|
407 | { |
---|
408 | encode3to4( source, d+off, len - d, outBuff, e ); |
---|
409 | e += 4; |
---|
410 | } // end if: some padding needed |
---|
411 | |
---|
412 | |
---|
413 | // Return value according to relevant encoding. |
---|
414 | try |
---|
415 | { |
---|
416 | return new String( outBuff, 0, e, PREFERRED_ENCODING ); |
---|
417 | } // end try |
---|
418 | catch (java.io.UnsupportedEncodingException uue) |
---|
419 | { |
---|
420 | return new String( outBuff, 0, e ); |
---|
421 | } // end catch |
---|
422 | |
---|
423 | } // end else: don't compress |
---|
424 | |
---|
425 | } // end encodeBytes |
---|
426 | |
---|
427 | |
---|
428 | |
---|
429 | |
---|
430 | |
---|
431 | /* ******** D E C O D I N G M E T H O D S ******** */ |
---|
432 | |
---|
433 | |
---|
434 | /** |
---|
435 | * Decodes four bytes from array <var>source</var> |
---|
436 | * and writes the resulting bytes (up to three of them) |
---|
437 | * to <var>destination</var>. |
---|
438 | * The source and destination arrays can be manipulated |
---|
439 | * anywhere along their length by specifying |
---|
440 | * <var>srcOffset</var> and <var>destOffset</var>. |
---|
441 | * This method does not check to make sure your arrays |
---|
442 | * are large enough to accomodate <var>srcOffset</var> + 4 for |
---|
443 | * the <var>source</var> array or <var>destOffset</var> + 3 for |
---|
444 | * the <var>destination</var> array. |
---|
445 | * This method returns the actual number of bytes that |
---|
446 | * were converted from the Base64 encoding. |
---|
447 | * |
---|
448 | * |
---|
449 | * @param source the array to convert |
---|
450 | * @param srcOffset the index where conversion begins |
---|
451 | * @param destination the array to hold the conversion |
---|
452 | * @param destOffset the index where output will be put |
---|
453 | * @return the number of decoded bytes converted |
---|
454 | * @since 1.3 |
---|
455 | */ |
---|
456 | private static int decode4to3( byte[] source, int srcOffset, byte[] destination, int destOffset ) |
---|
457 | { |
---|
458 | // Example: Dk== |
---|
459 | if( source[ srcOffset + 2] == EQUALS_SIGN ) |
---|
460 | { |
---|
461 | // Two ways to do the same thing. Don't know which way I like best. |
---|
462 | //int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 ) |
---|
463 | // | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 ); |
---|
464 | int outBuff = ( ( DECODABET[ source[ srcOffset ] ] & 0xFF ) << 18 ) |
---|
465 | | ( ( DECODABET[ source[ srcOffset + 1] ] & 0xFF ) << 12 ); |
---|
466 | |
---|
467 | destination[ destOffset ] = (byte)( outBuff >>> 16 ); |
---|
468 | return 1; |
---|
469 | } |
---|
470 | |
---|
471 | // Example: DkL= |
---|
472 | else if( source[ srcOffset + 3 ] == EQUALS_SIGN ) |
---|
473 | { |
---|
474 | // Two ways to do the same thing. Don't know which way I like best. |
---|
475 | //int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 ) |
---|
476 | // | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 ) |
---|
477 | // | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 ); |
---|
478 | int outBuff = ( ( DECODABET[ source[ srcOffset ] ] & 0xFF ) << 18 ) |
---|
479 | | ( ( DECODABET[ source[ srcOffset + 1 ] ] & 0xFF ) << 12 ) |
---|
480 | | ( ( DECODABET[ source[ srcOffset + 2 ] ] & 0xFF ) << 6 ); |
---|
481 | |
---|
482 | destination[ destOffset ] = (byte)( outBuff >>> 16 ); |
---|
483 | destination[ destOffset + 1 ] = (byte)( outBuff >>> 8 ); |
---|
484 | return 2; |
---|
485 | } |
---|
486 | |
---|
487 | // Example: DkLE |
---|
488 | else |
---|
489 | { |
---|
490 | try{ |
---|
491 | // Two ways to do the same thing. Don't know which way I like best. |
---|
492 | //int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 ) |
---|
493 | // | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 ) |
---|
494 | // | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 ) |
---|
495 | // | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 ); |
---|
496 | int outBuff = ( ( DECODABET[ source[ srcOffset ] ] & 0xFF ) << 18 ) |
---|
497 | | ( ( DECODABET[ source[ srcOffset + 1 ] ] & 0xFF ) << 12 ) |
---|
498 | | ( ( DECODABET[ source[ srcOffset + 2 ] ] & 0xFF ) << 6) |
---|
499 | | ( ( DECODABET[ source[ srcOffset + 3 ] ] & 0xFF ) ); |
---|
500 | |
---|
501 | |
---|
502 | destination[ destOffset ] = (byte)( outBuff >> 16 ); |
---|
503 | destination[ destOffset + 1 ] = (byte)( outBuff >> 8 ); |
---|
504 | destination[ destOffset + 2 ] = (byte)( outBuff ); |
---|
505 | |
---|
506 | return 3; |
---|
507 | }catch( Exception e){ |
---|
508 | System.out.println(""+source[srcOffset]+ ": " + ( DECODABET[ source[ srcOffset ] ] ) ); |
---|
509 | System.out.println(""+source[srcOffset+1]+ ": " + ( DECODABET[ source[ srcOffset + 1 ] ] ) ); |
---|
510 | System.out.println(""+source[srcOffset+2]+ ": " + ( DECODABET[ source[ srcOffset + 2 ] ] ) ); |
---|
511 | System.out.println(""+source[srcOffset+3]+ ": " + ( DECODABET[ source[ srcOffset + 3 ] ] ) ); |
---|
512 | return -1; |
---|
513 | } //e nd catch |
---|
514 | } |
---|
515 | } // end decodeToBytes |
---|
516 | |
---|
517 | |
---|
518 | |
---|
519 | |
---|
520 | /** |
---|
521 | * Very low-level access to decoding ASCII characters in |
---|
522 | * the form of a byte array. Does not support automatically |
---|
523 | * gunzipping or any other "fancy" features. |
---|
524 | * |
---|
525 | * @param source The Base64 encoded data |
---|
526 | * @param off The offset of where to begin decoding |
---|
527 | * @param len The length of characters to decode |
---|
528 | * @return decoded data |
---|
529 | * @since 1.3 |
---|
530 | */ |
---|
531 | public static byte[] decode( byte[] source, int off, int len ) |
---|
532 | { |
---|
533 | int len34 = len * 3 / 4; |
---|
534 | byte[] outBuff = new byte[ len34 ]; // Upper limit on size of output |
---|
535 | int outBuffPosn = 0; |
---|
536 | |
---|
537 | byte[] b4 = new byte[4]; |
---|
538 | int b4Posn = 0; |
---|
539 | int i = 0; |
---|
540 | byte sbiCrop = 0; |
---|
541 | byte sbiDecode = 0; |
---|
542 | for( i = off; i < off+len; i++ ) |
---|
543 | { |
---|
544 | sbiCrop = (byte)(source[i] & 0x7f); // Only the low seven bits |
---|
545 | sbiDecode = DECODABET[ sbiCrop ]; |
---|
546 | |
---|
547 | if( sbiDecode >= WHITE_SPACE_ENC ) // White space, Equals sign or better |
---|
548 | { |
---|
549 | if( sbiDecode >= EQUALS_SIGN_ENC ) |
---|
550 | { |
---|
551 | b4[ b4Posn++ ] = sbiCrop; |
---|
552 | if( b4Posn > 3 ) |
---|
553 | { |
---|
554 | outBuffPosn += decode4to3( b4, 0, outBuff, outBuffPosn ); |
---|
555 | b4Posn = 0; |
---|
556 | |
---|
557 | // If that was the equals sign, break out of 'for' loop |
---|
558 | if( sbiCrop == EQUALS_SIGN ) |
---|
559 | break; |
---|
560 | } // end if: quartet built |
---|
561 | |
---|
562 | } // end if: equals sign or better |
---|
563 | |
---|
564 | } // end if: white space, equals sign or better |
---|
565 | else |
---|
566 | { |
---|
567 | System.err.println( "Bad Base64 input character at " + i + ": " + source[i] + "(decimal)" ); |
---|
568 | return null; |
---|
569 | } // end else: |
---|
570 | } // each input character |
---|
571 | |
---|
572 | byte[] out = new byte[ outBuffPosn ]; |
---|
573 | System.arraycopy( outBuff, 0, out, 0, outBuffPosn ); |
---|
574 | return out; |
---|
575 | } // end decode |
---|
576 | |
---|
577 | |
---|
578 | |
---|
579 | |
---|
580 | /** |
---|
581 | * Decodes data from Base64 notation, automatically |
---|
582 | * detecting gzip-compressed data and decompressing it. |
---|
583 | * |
---|
584 | * @param s the string to decode |
---|
585 | * @return the decoded data |
---|
586 | * @since 1.4 |
---|
587 | */ |
---|
588 | public static byte[] decode( String s ) |
---|
589 | { |
---|
590 | byte[] bytes; |
---|
591 | try |
---|
592 | { |
---|
593 | bytes = s.getBytes( PREFERRED_ENCODING ); |
---|
594 | } // end try |
---|
595 | catch( java.io.UnsupportedEncodingException uee ) |
---|
596 | { |
---|
597 | bytes = s.getBytes(); |
---|
598 | } // end catch |
---|
599 | //</change> |
---|
600 | |
---|
601 | // Decode |
---|
602 | bytes = decode( bytes, 0, bytes.length ); |
---|
603 | |
---|
604 | |
---|
605 | // Check to see if it's gzip-compressed |
---|
606 | // GZIP Magic Two-Byte Number: 0x8b1f (35615) |
---|
607 | if( bytes != null && bytes.length >= 4 ) |
---|
608 | { |
---|
609 | |
---|
610 | int head = ((int)bytes[0] & 0xff) | ((bytes[1] << 8) & 0xff00); |
---|
611 | if( java.util.zip.GZIPInputStream.GZIP_MAGIC == head ) |
---|
612 | { |
---|
613 | java.io.ByteArrayInputStream bais = null; |
---|
614 | java.util.zip.GZIPInputStream gzis = null; |
---|
615 | java.io.ByteArrayOutputStream baos = null; |
---|
616 | byte[] buffer = new byte[2048]; |
---|
617 | int length = 0; |
---|
618 | |
---|
619 | try |
---|
620 | { |
---|
621 | baos = new java.io.ByteArrayOutputStream(); |
---|
622 | bais = new java.io.ByteArrayInputStream( bytes ); |
---|
623 | gzis = new java.util.zip.GZIPInputStream( bais ); |
---|
624 | |
---|
625 | while( ( length = gzis.read( buffer ) ) >= 0 ) |
---|
626 | { |
---|
627 | baos.write(buffer,0,length); |
---|
628 | } // end while: reading input |
---|
629 | |
---|
630 | // No error? Get new bytes. |
---|
631 | bytes = baos.toByteArray(); |
---|
632 | |
---|
633 | } // end try |
---|
634 | catch( java.io.IOException e ) |
---|
635 | { |
---|
636 | // Just return originally-decoded bytes |
---|
637 | } // end catch |
---|
638 | finally |
---|
639 | { |
---|
640 | try{ baos.close(); } catch( Exception e ){} |
---|
641 | try{ gzis.close(); } catch( Exception e ){} |
---|
642 | try{ bais.close(); } catch( Exception e ){} |
---|
643 | } // end finally |
---|
644 | |
---|
645 | } // end if: gzipped |
---|
646 | } // end if: bytes.length >= 2 |
---|
647 | |
---|
648 | return bytes; |
---|
649 | } // end decode |
---|
650 | |
---|
651 | |
---|
652 | |
---|
653 | |
---|
654 | |
---|
655 | } // end class Base64 |
---|