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94
95 package net.myvietnam.mvncore.misc;
96
97
107 public final class Base64
108 {
109 static private final int BASELENGTH = 255;
110 static private final int LOOKUPLENGTH = 64;
111 static private final int TWENTYFOURBITGROUP = 24;
112 static private final int EIGHTBIT = 8;
113 static private final int SIXTEENBIT = 16;
114 static private final int SIXBIT = 6;
115 static private final int FOURBYTE = 4;
116 static private final int SIGN = -128;
117 static private final byte PAD = (byte) '=';
118 static private byte [] base64Alphabet = new byte[BASELENGTH];
119 static private byte [] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
120
122 static
123 {
124 for (int i = 0; i < BASELENGTH; i++ )
125 {
126 base64Alphabet[i] = -1;
127 }
128 for (int i = 'Z'; i >= 'A'; i--)
129 {
130 base64Alphabet[i] = (byte) (i - 'A');
131 }
132 for (int i = 'z'; i>= 'a'; i--)
133 {
134 base64Alphabet[i] = (byte) (i - 'a' + 26);
135 }
136 for (int i = '9'; i >= '0'; i--)
137 {
138 base64Alphabet[i] = (byte) (i - '0' + 52);
139 }
140
141 base64Alphabet['+'] = 62;
142 base64Alphabet['/'] = 63;
143
144 for (int i = 0; i <= 25; i++ )
145 lookUpBase64Alphabet[i] = (byte) ('A' + i);
146
147 for (int i = 26, j = 0; i <= 51; i++, j++ )
148 lookUpBase64Alphabet[i] = (byte) ('a'+ j);
149
150 for (int i = 52, j = 0; i <= 61; i++, j++ )
151 lookUpBase64Alphabet[i] = (byte) ('0' + j);
152
153 lookUpBase64Alphabet[62] = (byte) '+';
154 lookUpBase64Alphabet[63] = (byte) '/';
155 }
156
157 public static boolean isBase64( String  isValidString )
158 {
159 return isArrayByteBase64(isValidString.getBytes());
160 }
161
162 public static boolean isBase64( byte octect )
163 {
164 return (octect == PAD || base64Alphabet[octect] != -1);
166 }
167
168 public static boolean isArrayByteBase64( byte[] arrayOctect )
169 {
170 int length = arrayOctect.length;
171 if (length == 0)
172 {
173 return true;
176 }
177 for (int i=0; i < length; i++)
178 {
179 if ( !Base64.isBase64(arrayOctect[i]) )
180 return false;
181 }
182 return true;
183 }
184
185
191 public static byte[] encode( byte[] binaryData )
192 {
193 int lengthDataBits = binaryData.length*EIGHTBIT;
194 int fewerThan24bits = lengthDataBits%TWENTYFOURBITGROUP;
195 int numberTriplets = lengthDataBits/TWENTYFOURBITGROUP;
196 byte encodedData[] = null;
197
198
199 if (fewerThan24bits != 0)
200 {
201 encodedData = new byte[ (numberTriplets + 1 ) * 4 ];
203 }
204 else
205 {
206 encodedData = new byte[ numberTriplets * 4 ];
208 }
209
210 byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
211
212 int encodedIndex = 0;
213 int dataIndex = 0;
214 int i = 0;
215 for ( i = 0; i<numberTriplets; i++ )
217 {
218 dataIndex = i*3;
219 b1 = binaryData[dataIndex];
220 b2 = binaryData[dataIndex + 1];
221 b3 = binaryData[dataIndex + 2];
222
223
225 l = (byte)(b2 & 0x0f);
226 k = (byte)(b1 & 0x03);
227
228 encodedIndex = i * 4;
229 byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
230 byte val2 = ((b2 & SIGN)==0)?(byte)(b2>>4):(byte)((b2)>>4^0xf0);
231 byte val3 = ((b3 & SIGN)==0)?(byte)(b3>>6):(byte)((b3)>>6^0xfc);
232
233 encodedData[encodedIndex] = lookUpBase64Alphabet[ val1 ];
234 encodedData[encodedIndex+1] =
238 lookUpBase64Alphabet[ val2 | ( k<<4 )];
239 encodedData[encodedIndex+2] =
240 lookUpBase64Alphabet[ (l <<2 ) | val3 ];
241 encodedData[encodedIndex+3] = lookUpBase64Alphabet[ b3 & 0x3f ];
242 }
243
244 dataIndex = i*3;
246 encodedIndex = i*4;
247 if (fewerThan24bits == EIGHTBIT )
248 {
249 b1 = binaryData[dataIndex];
250 k = (byte) ( b1 &0x03 );
251 byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
254 encodedData[encodedIndex] = lookUpBase64Alphabet[ val1 ];
255 encodedData[encodedIndex + 1] = lookUpBase64Alphabet[ k<<4 ];
256 encodedData[encodedIndex + 2] = PAD;
257 encodedData[encodedIndex + 3] = PAD;
258 }
259 else if (fewerThan24bits == SIXTEENBIT)
260 {
261
262 b1 = binaryData[dataIndex];
263 b2 = binaryData[dataIndex +1 ];
264 l = (byte) (b2 & 0x0f);
265 k = (byte) (b1 & 0x03);
266
267 byte val1 = ((b1 & SIGN) == 0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
268 byte val2 = ((b2 & SIGN) == 0)?(byte)(b2>>4):(byte)((b2)>>4^0xf0);
269
270 encodedData[encodedIndex] = lookUpBase64Alphabet[ val1 ];
271 encodedData[encodedIndex + 1] =
272 lookUpBase64Alphabet[ val2 | ( k<<4 )];
273 encodedData[encodedIndex + 2] = lookUpBase64Alphabet[ l<<2 ];
274 encodedData[encodedIndex + 3] = PAD;
275 }
276
277 return encodedData;
278 }
279
280
286 public static byte[] decode( byte[] base64Data )
287 {
288 if(base64Data.length == 0) { return new byte[0]; }
290
291 int numberQuadruple = base64Data.length/FOURBYTE;
292 byte decodedData[] = null;
293 byte b1=0,b2=0,b3=0, b4=0, marker0=0, marker1=0;
294
295
297 int encodedIndex = 0;
298 int dataIndex = 0;
299 {
300 int lastData = base64Data.length;
302 while (base64Data[lastData-1] == PAD)
304 {
305 if (--lastData == 0)
306 {
307 return new byte[0];
308 }
309 }
310 decodedData = new byte[ lastData - numberQuadruple ];
311 }
312
313 for (int i = 0; i < numberQuadruple; i++)
314 {
315 dataIndex = i * 4;
316 marker0 = base64Data[dataIndex + 2];
317 marker1 = base64Data[dataIndex + 3];
318
319 b1 = base64Alphabet[base64Data[dataIndex]];
320 b2 = base64Alphabet[base64Data[dataIndex +1]];
321
322 if (marker0 != PAD && marker1 != PAD)
323 {
324 b3 = base64Alphabet[ marker0 ];
326 b4 = base64Alphabet[ marker1 ];
327
328 decodedData[encodedIndex] = (byte)( b1 <<2 | b2>>4 ) ;
329 decodedData[encodedIndex + 1] =
330 (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
331 decodedData[encodedIndex + 2] = (byte)( b3<<6 | b4 );
332 }
333 else if (marker0 == PAD)
334 {
335 decodedData[encodedIndex] = (byte)( b1 <<2 | b2>>4 ) ;
337 }
338 else if (marker1 == PAD)
339 {
340 b3 = base64Alphabet[ marker0 ];
342
343 decodedData[encodedIndex] = (byte)( b1 <<2 | b2>>4 );
344 decodedData[encodedIndex + 1] =
345 (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
346 }
347 encodedIndex += 3;
348 }
349 return decodedData;
350 }
351
352
353 }
354 |
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