001: package dinamica;
002:
003: import java.util.Arrays;
004:
005: /** A very fast and memory efficient class to encode and decode to and from BASE64 in full accordance
006: * with RFC 2045.<br><br>
007: * On Windows XP sp1 with 1.4.2_04 and later ;), this encoder and decoder is about 10 times faster
008: * on small arrays (10 - 1000 bytes) and 2-3 times as fast on larger arrays (10000 - 1000000 bytes)
009: * compared to <code>sun.misc.Encoder()/Decoder()</code>.<br><br>
010: *
011: * On byte arrays the encoder is about 20% faster than Jakarta Commons Base64 Codec for encode and
012: * about 50% faster for decoding large arrays. This implementation is about twice as fast on very small
013: * arrays (< 30 bytes). If source/destination is a <code>String</code> this
014: * version is about three times as fast due to the fact that the Commons Codec result has to be recoded
015: * to a <code>String</code> from <code>byte[]</code>, which is very expensive.<br><br>
016: *
017: * This encode/decode algorithm doesn't create any temporary arrays as many other codecs do, it only
018: * allocates the resulting array. This produces less garbage and it is possible to handle arrays twice
019: * as large as algorithms that create a temporary array. (E.g. Jakarta Commons Codec). It is unknown
020: * whether Sun's <code>sun.misc.Encoder()/Decoder()</code> produce temporary arrays but since performance
021: * is quite low it probably does.<br><br>
022: *
023: * The encoder produces the same output as the Sun one except that the Sun's encoder appends
024: * a trailing line separator if the last character isn't a pad. Unclear why but it only adds to the
025: * length and is probably a side effect. Both are in conformance with RFC 2045 though.<br>
026: * Commons codec seem to always att a trailing line separator.<br><br>
027: *
028: * <b>Note!</b>
029: * The encode/decode method pairs (types) come in three versions with the <b>exact</b> same algorithm and
030: * thus a lot of code redundancy. This is to not create any temporary arrays for transcoding to/from different
031: * format types. The methods not used can simply be commented out.<br><br>
032: *
033: * There is also a "fast" version of all decode methods that works the same way as the normal ones, but
034: * har a few demands on the decoded input. Normally though, these fast verions should be used if the source if
035: * the input is known and it hasn't bee tampered with.<br><br>
036: *
037: * If you find the code useful or you find a bug, please send me a note at base64 @ miginfocom . com.
038: *
039: * Licence (BSD):
040: * ==============
041: *
042: * Copyright (c) 2004, Mikael Grev, MiG InfoCom AB. (base64 @ miginfocom . com)
043: * All rights reserved.
044: *
045: * Redistribution and use in source and binary forms, with or without modification,
046: * are permitted provided that the following conditions are met:
047: * Redistributions of source code must retain the above copyright notice, this list
048: * of conditions and the following disclaimer.
049: * Redistributions in binary form must reproduce the above copyright notice, this
050: * list of conditions and the following disclaimer in the documentation and/or other
051: * materials provided with the distribution.
052: * Neither the name of the MiG InfoCom AB nor the names of its contributors may be
053: * used to endorse or promote products derived from this software without specific
054: * prior written permission.
055: *
056: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
057: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
058: * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
059: * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
060: * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
061: * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
062: * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
063: * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
064: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
065: * OF SUCH DAMAGE.
066: *
067: * @version 2.2
068: * @author Mikael Grev
069: * Date: 2004-aug-02
070: * Time: 11:31:11
071: */
072:
073: public class Base64 {
074: private static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
075: .toCharArray();
076: private static final int[] IA = new int[256];
077: static {
078: Arrays.fill(IA, -1);
079: for (int i = 0, iS = CA.length; i < iS; i++)
080: IA[CA[i]] = i;
081: IA['='] = 0;
082: }
083:
084: // ****************************************************************************************
085: // * char[] version
086: // ****************************************************************************************
087:
088: /** Encodes a raw byte array into a BASE64 <code>char[]</code> representation i accordance with RFC 2045.
089: * @param sArr The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
090: * @param lineSep Optional "\r\n" after 76 characters, unless end of file.<br>
091: * No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a
092: * little faster.
093: * @return A BASE64 encoded array. Never <code>null</code>.
094: */
095: public final static char[] encodeToChar(byte[] sArr, boolean lineSep) {
096: // Check special case
097: int sLen = sArr != null ? sArr.length : 0;
098: if (sLen == 0)
099: return new char[0];
100:
101: int eLen = (sLen / 3) * 3; // Length of even 24-bits.
102: int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count
103: int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of returned array
104: char[] dArr = new char[dLen];
105:
106: // Encode even 24-bits
107: for (int s = 0, d = 0, cc = 0; s < eLen;) {
108: // Copy next three bytes into lower 24 bits of int, paying attension to sign.
109: int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8
110: | (sArr[s++] & 0xff);
111:
112: // Encode the int into four chars
113: dArr[d++] = CA[(i >>> 18) & 0x3f];
114: dArr[d++] = CA[(i >>> 12) & 0x3f];
115: dArr[d++] = CA[(i >>> 6) & 0x3f];
116: dArr[d++] = CA[i & 0x3f];
117:
118: // Add optional line separator
119: if (lineSep && ++cc == 19 && d < dLen - 2) {
120: dArr[d++] = '\r';
121: dArr[d++] = '\n';
122: cc = 0;
123: }
124: }
125:
126: // Pad and encode last bits if source isn't even 24 bits.
127: int left = sLen - eLen; // 0 - 2.
128: if (left > 0) {
129: // Prepare the int
130: int i = ((sArr[eLen] & 0xff) << 10)
131: | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);
132:
133: // Set last four chars
134: dArr[dLen - 4] = CA[i >> 12];
135: dArr[dLen - 3] = CA[(i >>> 6) & 0x3f];
136: dArr[dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';
137: dArr[dLen - 1] = '=';
138: }
139: return dArr;
140: }
141:
142: /** Decodes a BASE64 encoded char array. All illegal characters will be ignored and can handle both arrays with
143: * and without line separators.
144: * @param sArr The source array. <code>null</code> or length 0 will return an empty array.
145: * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
146: * (including '=') isn't divideable by 4. (I.e. definitely corrupted).
147: */
148: public final static byte[] decode(char[] sArr) {
149: // Check special case
150: int sLen = sArr != null ? sArr.length : 0;
151: if (sLen == 0)
152: return new byte[0];
153:
154: // Count illegal characters (including '\r', '\n') to know what size the returned array will be,
155: // so we don't have to reallocate & copy it later.
156: int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)
157: for (int i = 0; i < sLen; i++)
158: // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
159: if (IA[sArr[i]] < 0)
160: sepCnt++;
161:
162: // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
163: if ((sLen - sepCnt) % 4 != 0)
164: return null;
165:
166: int pad = 0;
167: for (int i = sLen; i > 1 && IA[sArr[--i]] <= 0;)
168: if (sArr[i] == '=')
169: pad++;
170:
171: int len = ((sLen - sepCnt) * 6 >> 3) - pad;
172:
173: byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
174:
175: for (int s = 0, d = 0; d < len;) {
176: // Assemble three bytes into an int from four "valid" characters.
177: int i = 0;
178: for (int j = 0; j < 4; j++) { // j only increased if a valid char was found.
179: int c = IA[sArr[s++]];
180: if (c >= 0)
181: i |= c << (18 - j * 6);
182: else
183: j--;
184: }
185: // Add the bytes
186: dArr[d++] = (byte) (i >> 16);
187: if (d < len) {
188: dArr[d++] = (byte) (i >> 8);
189: if (d < len)
190: dArr[d++] = (byte) i;
191: }
192: }
193: return dArr;
194: }
195:
196: /** Decodes a BASE64 encoded char array that is known to be resonably well formatted. The method is about twice as
197: * fast as {@link #decode(char[])}. The preconditions are:<br>
198: * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
199: * + Line separator must be "\r\n", as specified in RFC 2045
200: * + The array must not contain illegal characters within the encoded string<br>
201: * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
202: * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
203: * @return The decoded array of bytes. May be of length 0.
204: */
205: public final static byte[] decodeFast(char[] sArr) {
206: // Check special case
207: int sLen = sArr.length;
208: if (sLen == 0)
209: return new byte[0];
210:
211: int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
212:
213: // Trim illegal chars from start
214: while (sIx < eIx && IA[sArr[sIx]] < 0)
215: sIx++;
216:
217: // Trim illegal chars from end
218: while (eIx > 0 && IA[sArr[eIx]] < 0)
219: eIx--;
220:
221: // get the padding count (=) (0, 1 or 2)
222: int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count '=' at end.
223: int cCnt = eIx - sIx + 1; // Content count including possible separators
224: int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1
225: : 0;
226:
227: int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
228: byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
229:
230: // Decode all but the last 0 - 2 bytes.
231: int d = 0;
232: for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
233: // Assemble three bytes into an int from four "valid" characters.
234: int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12
235: | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];
236:
237: // Add the bytes
238: dArr[d++] = (byte) (i >> 16);
239: dArr[d++] = (byte) (i >> 8);
240: dArr[d++] = (byte) i;
241:
242: // If line separator, jump over it.
243: if (sepCnt > 0 && ++cc == 19) {
244: sIx += 2;
245: cc = 0;
246: }
247: }
248:
249: if (d < len) {
250: // Decode last 1-3 bytes (incl '=') into 1-3 bytes
251: int i = 0;
252: for (int j = 0; sIx <= eIx - pad; j++)
253: i |= IA[sArr[sIx++]] << (18 - j * 6);
254:
255: for (int r = 16; d < len; r -= 8)
256: dArr[d++] = (byte) (i >> r);
257: }
258:
259: return dArr;
260: }
261:
262: // ****************************************************************************************
263: // * byte[] version
264: // ****************************************************************************************
265:
266: /** Encodes a raw byte array into a BASE64 <code>byte[]</code> representation i accordance with RFC 2045.
267: * @param sArr The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
268: * @param lineSep Optional "\r\n" after 76 characters, unless end of file.<br>
269: * No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a
270: * little faster.
271: * @return A BASE64 encoded array. Never <code>null</code>.
272: */
273: public final static byte[] encodeToByte(byte[] sArr, boolean lineSep) {
274: // Check special case
275: int sLen = sArr != null ? sArr.length : 0;
276: if (sLen == 0)
277: return new byte[0];
278:
279: int eLen = (sLen / 3) * 3; // Length of even 24-bits.
280: int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count
281: int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of returned array
282: byte[] dArr = new byte[dLen];
283:
284: // Encode even 24-bits
285: for (int s = 0, d = 0, cc = 0; s < eLen;) {
286: // Copy next three bytes into lower 24 bits of int, paying attension to sign.
287: int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8
288: | (sArr[s++] & 0xff);
289:
290: // Encode the int into four chars
291: dArr[d++] = (byte) CA[(i >>> 18) & 0x3f];
292: dArr[d++] = (byte) CA[(i >>> 12) & 0x3f];
293: dArr[d++] = (byte) CA[(i >>> 6) & 0x3f];
294: dArr[d++] = (byte) CA[i & 0x3f];
295:
296: // Add optional line separator
297: if (lineSep && ++cc == 19 && d < dLen - 2) {
298: dArr[d++] = '\r';
299: dArr[d++] = '\n';
300: cc = 0;
301: }
302: }
303:
304: // Pad and encode last bits if source isn't an even 24 bits.
305: int left = sLen - eLen; // 0 - 2.
306: if (left > 0) {
307: // Prepare the int
308: int i = ((sArr[eLen] & 0xff) << 10)
309: | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);
310:
311: // Set last four chars
312: dArr[dLen - 4] = (byte) CA[i >> 12];
313: dArr[dLen - 3] = (byte) CA[(i >>> 6) & 0x3f];
314: dArr[dLen - 2] = left == 2 ? (byte) CA[i & 0x3f]
315: : (byte) '=';
316: dArr[dLen - 1] = '=';
317: }
318: return dArr;
319: }
320:
321: /** Decodes a BASE64 encoded byte array. All illegal characters will be ignored and can handle both arrays with
322: * and without line separators.
323: * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
324: * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
325: * (including '=') isn't divideable by 4. (I.e. definitely corrupted).
326: */
327: public final static byte[] decode(byte[] sArr) {
328: // Check special case
329: int sLen = sArr.length;
330:
331: // Count illegal characters (including '\r', '\n') to know what size the returned array will be,
332: // so we don't have to reallocate & copy it later.
333: int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)
334: for (int i = 0; i < sLen; i++)
335: // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
336: if (IA[sArr[i] & 0xff] < 0)
337: sepCnt++;
338:
339: // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
340: if ((sLen - sepCnt) % 4 != 0)
341: return null;
342:
343: int pad = 0;
344: for (int i = sLen; i > 1 && IA[sArr[--i] & 0xff] <= 0;)
345: if (sArr[i] == '=')
346: pad++;
347:
348: int len = ((sLen - sepCnt) * 6 >> 3) - pad;
349:
350: byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
351:
352: for (int s = 0, d = 0; d < len;) {
353: // Assemble three bytes into an int from four "valid" characters.
354: int i = 0;
355: for (int j = 0; j < 4; j++) { // j only increased if a valid char was found.
356: int c = IA[sArr[s++] & 0xff];
357: if (c >= 0)
358: i |= c << (18 - j * 6);
359: else
360: j--;
361: }
362:
363: // Add the bytes
364: dArr[d++] = (byte) (i >> 16);
365: if (d < len) {
366: dArr[d++] = (byte) (i >> 8);
367: if (d < len)
368: dArr[d++] = (byte) i;
369: }
370: }
371:
372: return dArr;
373: }
374:
375: /** Decodes a BASE64 encoded byte array that is known to be resonably well formatted. The method is about twice as
376: * fast as {@link #decode(byte[])}. The preconditions are:<br>
377: * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
378: * + Line separator must be "\r\n", as specified in RFC 2045
379: * + The array must not contain illegal characters within the encoded string<br>
380: * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
381: * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
382: * @return The decoded array of bytes. May be of length 0.
383: */
384: public final static byte[] decodeFast(byte[] sArr) {
385: // Check special case
386: int sLen = sArr.length;
387: if (sLen == 0)
388: return new byte[0];
389:
390: int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
391:
392: // Trim illegal chars from start
393: while (sIx < eIx && IA[sArr[sIx] & 0xff] < 0)
394: sIx++;
395:
396: // Trim illegal chars from end
397: while (eIx > 0 && IA[sArr[eIx] & 0xff] < 0)
398: eIx--;
399:
400: // get the padding count (=) (0, 1 or 2)
401: int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count '=' at end.
402: int cCnt = eIx - sIx + 1; // Content count including possible separators
403: int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1
404: : 0;
405:
406: int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
407: byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
408:
409: // Decode all but the last 0 - 2 bytes.
410: int d = 0;
411: for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
412: // Assemble three bytes into an int from four "valid" characters.
413: int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12
414: | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];
415:
416: // Add the bytes
417: dArr[d++] = (byte) (i >> 16);
418: dArr[d++] = (byte) (i >> 8);
419: dArr[d++] = (byte) i;
420:
421: // If line separator, jump over it.
422: if (sepCnt > 0 && ++cc == 19) {
423: sIx += 2;
424: cc = 0;
425: }
426: }
427:
428: if (d < len) {
429: // Decode last 1-3 bytes (incl '=') into 1-3 bytes
430: int i = 0;
431: for (int j = 0; sIx <= eIx - pad; j++)
432: i |= IA[sArr[sIx++]] << (18 - j * 6);
433:
434: for (int r = 16; d < len; r -= 8)
435: dArr[d++] = (byte) (i >> r);
436: }
437:
438: return dArr;
439: }
440:
441: // ****************************************************************************************
442: // * String version
443: // ****************************************************************************************
444:
445: /** Encodes a raw byte array into a BASE64 <code>String</code> representation i accordance with RFC 2045.
446: * @param sArr The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
447: * @param lineSep Optional "\r\n" after 76 characters, unless end of file.<br>
448: * No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a
449: * little faster.
450: * @return A BASE64 encoded array. Never <code>null</code>.
451: */
452: public final static String encodeToString(byte[] sArr,
453: boolean lineSep) {
454: // Reuse char[] since we can't create a String incrementally anyway and StringBuffer/Builder would be slower.
455: return new String(encodeToChar(sArr, lineSep));
456: }
457:
458: /** Decodes a BASE64 encoded <code>String</code>. All illegal characters will be ignored and can handle both strings with
459: * and without line separators.<br>
460: * <b>Note!</b> It can be up to about 2x the speed to call <code>decode(str.toCharArray())</code> instead. That
461: * will create a temporary array though. This version will use <code>str.charAt(i)</code> to iterate the string.
462: * @param str The source string. <code>null</code> or length 0 will return an empty array.
463: * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
464: * (including '=') isn't divideable by 4. (I.e. definitely corrupted).
465: */
466: public final static byte[] decode(String str) {
467: // Check special case
468: int sLen = str != null ? str.length() : 0;
469: if (sLen == 0)
470: return new byte[0];
471:
472: // Count illegal characters (including '\r', '\n') to know what size the returned array will be,
473: // so we don't have to reallocate & copy it later.
474: int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)
475: for (int i = 0; i < sLen; i++)
476: // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
477: if (IA[str.charAt(i)] < 0)
478: sepCnt++;
479:
480: // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
481: if ((sLen - sepCnt) % 4 != 0)
482: return null;
483:
484: // Count '=' at end
485: int pad = 0;
486: for (int i = sLen; i > 1 && IA[str.charAt(--i)] <= 0;)
487: if (str.charAt(i) == '=')
488: pad++;
489:
490: int len = ((sLen - sepCnt) * 6 >> 3) - pad;
491:
492: byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
493:
494: for (int s = 0, d = 0; d < len;) {
495: // Assemble three bytes into an int from four "valid" characters.
496: int i = 0;
497: for (int j = 0; j < 4; j++) { // j only increased if a valid char was found.
498: int c = IA[str.charAt(s++)];
499: if (c >= 0)
500: i |= c << (18 - j * 6);
501: else
502: j--;
503: }
504: // Add the bytes
505: dArr[d++] = (byte) (i >> 16);
506: if (d < len) {
507: dArr[d++] = (byte) (i >> 8);
508: if (d < len)
509: dArr[d++] = (byte) i;
510: }
511: }
512: return dArr;
513: }
514:
515: /** Decodes a BASE64 encoded string that is known to be resonably well formatted. The method is about twice as
516: * fast as {@link #decode(String)}. The preconditions are:<br>
517: * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
518: * + Line separator must be "\r\n", as specified in RFC 2045
519: * + The array must not contain illegal characters within the encoded string<br>
520: * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
521: * @param s The source string. Length 0 will return an empty array. <code>null</code> will throw an exception.
522: * @return The decoded array of bytes. May be of length 0.
523: */
524: public final static byte[] decodeFast(String s) {
525: // Check special case
526: int sLen = s.length();
527: if (sLen == 0)
528: return new byte[0];
529:
530: int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
531:
532: // Trim illegal chars from start
533: while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0)
534: sIx++;
535:
536: // Trim illegal chars from end
537: while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0)
538: eIx--;
539:
540: // get the padding count (=) (0, 1 or 2)
541: int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2
542: : 1) : 0; // Count '=' at end.
543: int cCnt = eIx - sIx + 1; // Content count including possible separators
544: int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1
545: : 0;
546:
547: int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
548: byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
549:
550: // Decode all but the last 0 - 2 bytes.
551: int d = 0;
552: for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
553: // Assemble three bytes into an int from four "valid" characters.
554: int i = IA[s.charAt(sIx++)] << 18
555: | IA[s.charAt(sIx++)] << 12
556: | IA[s.charAt(sIx++)] << 6 | IA[s.charAt(sIx++)];
557:
558: // Add the bytes
559: dArr[d++] = (byte) (i >> 16);
560: dArr[d++] = (byte) (i >> 8);
561: dArr[d++] = (byte) i;
562:
563: // If line separator, jump over it.
564: if (sepCnt > 0 && ++cc == 19) {
565: sIx += 2;
566: cc = 0;
567: }
568: }
569:
570: if (d < len) {
571: // Decode last 1-3 bytes (incl '=') into 1-3 bytes
572: int i = 0;
573: for (int j = 0; sIx <= eIx - pad; j++)
574: i |= IA[s.charAt(sIx++)] << (18 - j * 6);
575:
576: for (int r = 16; d < len; r -= 8)
577: dArr[d++] = (byte) (i >> r);
578: }
579:
580: return dArr;
581: }
582: }
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