1 /*
2 * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util;
27
28 import java.io.FilterOutputStream;
29 import java.io.InputStream;
30 import java.io.IOException;
31 import java.io.OutputStream;
32 import java.nio.ByteBuffer;
33 import java.nio.charset.StandardCharsets;
34 import jdk.internal.HotSpotIntrinsicCandidate;
35
36 /**
37 * This class consists exclusively of static methods for obtaining
38 * encoders and decoders for the Base64 encoding scheme. The
39 * implementation of this class supports the following types of Base64
40 * as specified in
41 * <a href="http://www.ietf.org/rfc/rfc4648.txt">RFC 4648</a> and
42 * <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>.
43 *
44 * <ul>
45 * <li><a id="basic"><b>Basic</b></a>
46 * <p> Uses "The Base64 Alphabet" as specified in Table 1 of
47 * RFC 4648 and RFC 2045 for encoding and decoding operation.
48 * The encoder does not add any line feed (line separator)
49 * character. The decoder rejects data that contains characters
50 * outside the base64 alphabet.</p></li>
51 *
52 * <li><a id="url"><b>URL and Filename safe</b></a>
53 * <p> Uses the "URL and Filename safe Base64 Alphabet" as specified
54 * in Table 2 of RFC 4648 for encoding and decoding. The
55 * encoder does not add any line feed (line separator) character.
56 * The decoder rejects data that contains characters outside the
57 * base64 alphabet.</p></li>
58 *
59 * <li><a id="mime"><b>MIME</b></a>
60 * <p> Uses "The Base64 Alphabet" as specified in Table 1 of
61 * RFC 2045 for encoding and decoding operation. The encoded output
62 * must be represented in lines of no more than 76 characters each
63 * and uses a carriage return {@code '\r'} followed immediately by
64 * a linefeed {@code '\n'} as the line separator. No line separator
65 * is added to the end of the encoded output. All line separators
66 * or other characters not found in the base64 alphabet table are
67 * ignored in decoding operation.</p></li>
68 * </ul>
69 *
70 * <p> Unless otherwise noted, passing a {@code null} argument to a
71 * method of this class will cause a {@link java.lang.NullPointerException
72 * NullPointerException} to be thrown.
73 *
74 * @author Xueming Shen
75 * @since 1.8
76 */
77
78 public class Base64 {
79
80 private Base64() {}
81
82 /**
83 * Returns a {@link Encoder} that encodes using the
84 * <a href="#basic">Basic</a> type base64 encoding scheme.
85 *
86 * @return A Base64 encoder.
87 */
88 public static Encoder getEncoder() {
89 return Encoder.RFC4648;
90 }
91
92 /**
93 * Returns a {@link Encoder} that encodes using the
94 * <a href="#url">URL and Filename safe</a> type base64
95 * encoding scheme.
96 *
97 * @return A Base64 encoder.
98 */
99 public static Encoder getUrlEncoder() {
100 return Encoder.RFC4648_URLSAFE;
101 }
102
103 /**
104 * Returns a {@link Encoder} that encodes using the
105 * <a href="#mime">MIME</a> type base64 encoding scheme.
106 *
107 * @return A Base64 encoder.
108 */
109 public static Encoder getMimeEncoder() {
110 return Encoder.RFC2045;
111 }
112
113 /**
114 * Returns a {@link Encoder} that encodes using the
115 * <a href="#mime">MIME</a> type base64 encoding scheme
116 * with specified line length and line separators.
117 *
118 * @param lineLength
119 * the length of each output line (rounded down to nearest multiple
120 * of 4). If the rounded down line length is not a positive value,
121 * the output will not be separated in lines
122 * @param lineSeparator
123 * the line separator for each output line
124 *
125 * @return A Base64 encoder.
126 *
127 * @throws IllegalArgumentException if {@code lineSeparator} includes any
128 * character of "The Base64 Alphabet" as specified in Table 1 of
129 * RFC 2045.
130 */
131 public static Encoder getMimeEncoder(int lineLength, byte[] lineSeparator) {
132 Objects.requireNonNull(lineSeparator);
133 int[] base64 = Decoder.fromBase64;
134 for (byte b : lineSeparator) {
135 if (base64[b & 0xff] != -1)
136 throw new IllegalArgumentException(
137 "Illegal base64 line separator character 0x" + Integer.toString(b, 16));
138 }
139 // round down to nearest multiple of 4
140 lineLength &= ~0b11;
141 if (lineLength <= 0) {
142 return Encoder.RFC4648;
143 }
144 return new Encoder(false, lineSeparator, lineLength, true);
145 }
146
147 /**
148 * Returns a {@link Decoder} that decodes using the
149 * <a href="#basic">Basic</a> type base64 encoding scheme.
150 *
151 * @return A Base64 decoder.
152 */
153 public static Decoder getDecoder() {
154 return Decoder.RFC4648;
155 }
156
157 /**
158 * Returns a {@link Decoder} that decodes using the
159 * <a href="#url">URL and Filename safe</a> type base64
160 * encoding scheme.
161 *
162 * @return A Base64 decoder.
163 */
164 public static Decoder getUrlDecoder() {
165 return Decoder.RFC4648_URLSAFE;
166 }
167
168 /**
169 * Returns a {@link Decoder} that decodes using the
170 * <a href="#mime">MIME</a> type base64 decoding scheme.
171 *
172 * @return A Base64 decoder.
173 */
174 public static Decoder getMimeDecoder() {
175 return Decoder.RFC2045;
176 }
177
178 /**
179 * This class implements an encoder for encoding byte data using
180 * the Base64 encoding scheme as specified in RFC 4648 and RFC 2045.
181 *
182 * <p> Instances of {@link Encoder} class are safe for use by
183 * multiple concurrent threads.
184 *
185 * <p> Unless otherwise noted, passing a {@code null} argument to
186 * a method of this class will cause a
187 * {@link java.lang.NullPointerException NullPointerException} to
188 * be thrown.
189 *
190 * @see Decoder
191 * @since 1.8
192 */
193 public static class Encoder {
194
195 private final byte[] newline;
196 private final int linemax;
197 private final boolean isURL;
198 private final boolean doPadding;
199
200 private Encoder(boolean isURL, byte[] newline, int linemax, boolean doPadding) {
201 this.isURL = isURL;
202 this.newline = newline;
203 this.linemax = linemax;
204 this.doPadding = doPadding;
205 }
206
207 /**
208 * This array is a lookup table that translates 6-bit positive integer
209 * index values into their "Base64 Alphabet" equivalents as specified
210 * in "Table 1: The Base64 Alphabet" of RFC 2045 (and RFC 4648).
211 */
212 private static final char[] toBase64 = {
213 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
214 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
215 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
216 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
217 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
218 };
219
220 /**
221 * It's the lookup table for "URL and Filename safe Base64" as specified
222 * in Table 2 of the RFC 4648, with the '+' and '/' changed to '-' and
223 * '_'. This table is used when BASE64_URL is specified.
224 */
225 private static final char[] toBase64URL = {
226 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
227 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
228 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
229 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
230 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'
231 };
232
233 private static final int MIMELINEMAX = 76;
234 private static final byte[] CRLF = new byte[] {'\r', '\n'};
235
236 static final Encoder RFC4648 = new Encoder(false, null, -1, true);
237 static final Encoder RFC4648_URLSAFE = new Encoder(true, null, -1, true);
238 static final Encoder RFC2045 = new Encoder(false, CRLF, MIMELINEMAX, true);
239
240 private final int outLength(int srclen) {
241 int len = 0;
242 if (doPadding) {
243 len = 4 * ((srclen + 2) / 3);
244 } else {
245 int n = srclen % 3;
246 len = 4 * (srclen / 3) + (n == 0 ? 0 : n + 1);
247 }
248 if (linemax > 0) // line separators
249 len += (len - 1) / linemax * newline.length;
250 return len;
251 }
252
253 /**
254 * Encodes all bytes from the specified byte array into a newly-allocated
255 * byte array using the {@link Base64} encoding scheme. The returned byte
256 * array is of the length of the resulting bytes.
257 *
258 * @param src
259 * the byte array to encode
260 * @return A newly-allocated byte array containing the resulting
261 * encoded bytes.
262 */
263 public byte[] encode(byte[] src) {
264 int len = outLength(src.length); // dst array size
265 byte[] dst = new byte[len];
266 int ret = encode0(src, 0, src.length, dst);
267 if (ret != dst.length)
268 return Arrays.copyOf(dst, ret);
269 return dst;
270 }
271
272 /**
273 * Encodes all bytes from the specified byte array using the
274 * {@link Base64} encoding scheme, writing the resulting bytes to the
275 * given output byte array, starting at offset 0.
276 *
277 * <p> It is the responsibility of the invoker of this method to make
278 * sure the output byte array {@code dst} has enough space for encoding
279 * all bytes from the input byte array. No bytes will be written to the
280 * output byte array if the output byte array is not big enough.
281 *
282 * @param src
283 * the byte array to encode
284 * @param dst
285 * the output byte array
286 * @return The number of bytes written to the output byte array
287 *
288 * @throws IllegalArgumentException if {@code dst} does not have enough
289 * space for encoding all input bytes.
290 */
291 public int encode(byte[] src, byte[] dst) {
292 int len = outLength(src.length); // dst array size
293 if (dst.length < len)
294 throw new IllegalArgumentException(
295 "Output byte array is too small for encoding all input bytes");
296 return encode0(src, 0, src.length, dst);
297 }
298
299 /**
300 * Encodes the specified byte array into a String using the {@link Base64}
301 * encoding scheme.
302 *
303 * <p> This method first encodes all input bytes into a base64 encoded
304 * byte array and then constructs a new String by using the encoded byte
305 * array and the {@link java.nio.charset.StandardCharsets#ISO_8859_1
306 * ISO-8859-1} charset.
307 *
308 * <p> In other words, an invocation of this method has exactly the same
309 * effect as invoking
310 * {@code new String(encode(src), StandardCharsets.ISO_8859_1)}.
311 *
312 * @param src
313 * the byte array to encode
314 * @return A String containing the resulting Base64 encoded characters
315 */
316 @SuppressWarnings("deprecation")
317 public String encodeToString(byte[] src) {
318 byte[] encoded = encode(src);
319 return new String(encoded, 0, 0, encoded.length);
320 }
321
322 /**
323 * Encodes all remaining bytes from the specified byte buffer into
324 * a newly-allocated ByteBuffer using the {@link Base64} encoding
325 * scheme.
326 *
327 * Upon return, the source buffer's position will be updated to
328 * its limit; its limit will not have been changed. The returned
329 * output buffer's position will be zero and its limit will be the
330 * number of resulting encoded bytes.
331 *
332 * @param buffer
333 * the source ByteBuffer to encode
334 * @return A newly-allocated byte buffer containing the encoded bytes.
335 */
336 public ByteBuffer encode(ByteBuffer buffer) {
337 int len = outLength(buffer.remaining());
338 byte[] dst = new byte[len];
339 int ret = 0;
340 if (buffer.hasArray()) {
341 ret = encode0(buffer.array(),
342 buffer.arrayOffset() + buffer.position(),
343 buffer.arrayOffset() + buffer.limit(),
344 dst);
345 buffer.position(buffer.limit());
346 } else {
347 byte[] src = new byte[buffer.remaining()];
348 buffer.get(src);
349 ret = encode0(src, 0, src.length, dst);
350 }
351 if (ret != dst.length)
352 dst = Arrays.copyOf(dst, ret);
353 return ByteBuffer.wrap(dst);
354 }
355
356 /**
357 * Wraps an output stream for encoding byte data using the {@link Base64}
358 * encoding scheme.
359 *
360 * <p> It is recommended to promptly close the returned output stream after
361 * use, during which it will flush all possible leftover bytes to the underlying
362 * output stream. Closing the returned output stream will close the underlying
363 * output stream.
364 *
365 * @param os
366 * the output stream.
367 * @return the output stream for encoding the byte data into the
368 * specified Base64 encoded format
369 */
370 public OutputStream wrap(OutputStream os) {
371 Objects.requireNonNull(os);
372 return new EncOutputStream(os, isURL ? toBase64URL : toBase64,
373 newline, linemax, doPadding);
374 }
375
376 /**
377 * Returns an encoder instance that encodes equivalently to this one,
378 * but without adding any padding character at the end of the encoded
379 * byte data.
380 *
381 * <p> The encoding scheme of this encoder instance is unaffected by
382 * this invocation. The returned encoder instance should be used for
383 * non-padding encoding operation.
384 *
385 * @return an equivalent encoder that encodes without adding any
386 * padding character at the end
387 */
388 public Encoder withoutPadding() {
389 if (!doPadding)
390 return this;
391 return new Encoder(isURL, newline, linemax, false);
392 }
393
394 @HotSpotIntrinsicCandidate
395 private void encodeBlock(byte[] src, int sp, int sl, byte[] dst, int dp, boolean isURL) {
396 char[] base64 = isURL ? toBase64URL : toBase64;
397 for (int sp0 = sp, dp0 = dp ; sp0 < sl; ) {
398 int bits = (src[sp0++] & 0xff) << 16 |
399 (src[sp0++] & 0xff) << 8 |
400 (src[sp0++] & 0xff);
401 dst[dp0++] = (byte)base64[(bits >>> 18) & 0x3f];
402 dst[dp0++] = (byte)base64[(bits >>> 12) & 0x3f];
403 dst[dp0++] = (byte)base64[(bits >>> 6) & 0x3f];
404 dst[dp0++] = (byte)base64[bits & 0x3f];
405 }
406 }
407
408 private int encode0(byte[] src, int off, int end, byte[] dst) {
409 char[] base64 = isURL ? toBase64URL : toBase64;
410 int sp = off;
411 int slen = (end - off) / 3 * 3;
412 int sl = off + slen;
413 if (linemax > 0 && slen > linemax / 4 * 3)
414 slen = linemax / 4 * 3;
415 int dp = 0;
416 while (sp < sl) {
417 int sl0 = Math.min(sp + slen, sl);
418 encodeBlock(src, sp, sl0, dst, dp, isURL);
419 int dlen = (sl0 - sp) / 3 * 4;
420 dp += dlen;
421 sp = sl0;
422 if (dlen == linemax && sp < end) {
423 for (byte b : newline){
424 dst[dp++] = b;
425 }
426 }
427 }
428 if (sp < end) { // 1 or 2 leftover bytes
429 int b0 = src[sp++] & 0xff;
430 dst[dp++] = (byte)base64[b0 >> 2];
431 if (sp == end) {
432 dst[dp++] = (byte)base64[(b0 << 4) & 0x3f];
433 if (doPadding) {
434 dst[dp++] = '=';
435 dst[dp++] = '=';
436 }
437 } else {
438 int b1 = src[sp++] & 0xff;
439 dst[dp++] = (byte)base64[(b0 << 4) & 0x3f | (b1 >> 4)];
440 dst[dp++] = (byte)base64[(b1 << 2) & 0x3f];
441 if (doPadding) {
442 dst[dp++] = '=';
443 }
444 }
445 }
446 return dp;
447 }
448 }
449
450 /**
451 * This class implements a decoder for decoding byte data using the
452 * Base64 encoding scheme as specified in RFC 4648 and RFC 2045.
453 *
454 * <p> The Base64 padding character {@code '='} is accepted and
455 * interpreted as the end of the encoded byte data, but is not
456 * required. So if the final unit of the encoded byte data only has
457 * two or three Base64 characters (without the corresponding padding
458 * character(s) padded), they are decoded as if followed by padding
459 * character(s). If there is a padding character present in the
460 * final unit, the correct number of padding character(s) must be
461 * present, otherwise {@code IllegalArgumentException} (
462 * {@code IOException} when reading from a Base64 stream) is thrown
463 * during decoding.
464 *
465 * <p> Instances of {@link Decoder} class are safe for use by
466 * multiple concurrent threads.
467 *
468 * <p> Unless otherwise noted, passing a {@code null} argument to
469 * a method of this class will cause a
470 * {@link java.lang.NullPointerException NullPointerException} to
471 * be thrown.
472 *
473 * @see Encoder
474 * @since 1.8
475 */
476 public static class Decoder {
477
478 private final boolean isURL;
479 private final boolean isMIME;
480
481 private Decoder(boolean isURL, boolean isMIME) {
482 this.isURL = isURL;
483 this.isMIME = isMIME;
484 }
485
486 /**
487 * Lookup table for decoding unicode characters drawn from the
488 * "Base64 Alphabet" (as specified in Table 1 of RFC 2045) into
489 * their 6-bit positive integer equivalents. Characters that
490 * are not in the Base64 alphabet but fall within the bounds of
491 * the array are encoded to -1.
492 *
493 */
494 private static final int[] fromBase64 = new int[256];
495 static {
496 Arrays.fill(fromBase64, -1);
497 for (int i = 0; i < Encoder.toBase64.length; i++)
498 fromBase64[Encoder.toBase64[i]] = i;
499 fromBase64['='] = -2;
500 }
501
502 /**
503 * Lookup table for decoding "URL and Filename safe Base64 Alphabet"
504 * as specified in Table2 of the RFC 4648.
505 */
506 private static final int[] fromBase64URL = new int[256];
507
508 static {
509 Arrays.fill(fromBase64URL, -1);
510 for (int i = 0; i < Encoder.toBase64URL.length; i++)
511 fromBase64URL[Encoder.toBase64URL[i]] = i;
512 fromBase64URL['='] = -2;
513 }
514
515 static final Decoder RFC4648 = new Decoder(false, false);
516 static final Decoder RFC4648_URLSAFE = new Decoder(true, false);
517 static final Decoder RFC2045 = new Decoder(false, true);
518
519 /**
520 * Decodes all bytes from the input byte array using the {@link Base64}
521 * encoding scheme, writing the results into a newly-allocated output
522 * byte array. The returned byte array is of the length of the resulting
523 * bytes.
524 *
525 * @param src
526 * the byte array to decode
527 *
528 * @return A newly-allocated byte array containing the decoded bytes.
529 *
530 * @throws IllegalArgumentException
531 * if {@code src} is not in valid Base64 scheme
532 */
533 public byte[] decode(byte[] src) {
534 byte[] dst = new byte[outLength(src, 0, src.length)];
535 int ret = decode0(src, 0, src.length, dst);
536 if (ret != dst.length) {
537 dst = Arrays.copyOf(dst, ret);
538 }
539 return dst;
540 }
541
542 /**
543 * Decodes a Base64 encoded String into a newly-allocated byte array
544 * using the {@link Base64} encoding scheme.
545 *
546 * <p> An invocation of this method has exactly the same effect as invoking
547 * {@code decode(src.getBytes(StandardCharsets.ISO_8859_1))}
548 *
549 * @param src
550 * the string to decode
551 *
552 * @return A newly-allocated byte array containing the decoded bytes.
553 *
554 * @throws IllegalArgumentException
555 * if {@code src} is not in valid Base64 scheme
556 */
557 public byte[] decode(String src) {
558 return decode(src.getBytes(StandardCharsets.ISO_8859_1));
559 }
560
561 /**
562 * Decodes all bytes from the input byte array using the {@link Base64}
563 * encoding scheme, writing the results into the given output byte array,
564 * starting at offset 0.
565 *
566 * <p> It is the responsibility of the invoker of this method to make
567 * sure the output byte array {@code dst} has enough space for decoding
568 * all bytes from the input byte array. No bytes will be written to
569 * the output byte array if the output byte array is not big enough.
570 *
571 * <p> If the input byte array is not in valid Base64 encoding scheme
572 * then some bytes may have been written to the output byte array before
573 * IllegalargumentException is thrown.
574 *
575 * @param src
576 * the byte array to decode
577 * @param dst
578 * the output byte array
579 *
580 * @return The number of bytes written to the output byte array
581 *
582 * @throws IllegalArgumentException
583 * if {@code src} is not in valid Base64 scheme, or {@code dst}
584 * does not have enough space for decoding all input bytes.
585 */
586 public int decode(byte[] src, byte[] dst) {
587 int len = outLength(src, 0, src.length);
588 if (dst.length < len)
589 throw new IllegalArgumentException(
590 "Output byte array is too small for decoding all input bytes");
591 return decode0(src, 0, src.length, dst);
592 }
593
594 /**
595 * Decodes all bytes from the input byte buffer using the {@link Base64}
596 * encoding scheme, writing the results into a newly-allocated ByteBuffer.
597 *
598 * <p> Upon return, the source buffer's position will be updated to
599 * its limit; its limit will not have been changed. The returned
600 * output buffer's position will be zero and its limit will be the
601 * number of resulting decoded bytes
602 *
603 * <p> {@code IllegalArgumentException} is thrown if the input buffer
604 * is not in valid Base64 encoding scheme. The position of the input
605 * buffer will not be advanced in this case.
606 *
607 * @param buffer
608 * the ByteBuffer to decode
609 *
610 * @return A newly-allocated byte buffer containing the decoded bytes
611 *
612 * @throws IllegalArgumentException
613 * if {@code src} is not in valid Base64 scheme.
614 */
615 public ByteBuffer decode(ByteBuffer buffer) {
616 int pos0 = buffer.position();
617 try {
618 byte[] src;
619 int sp, sl;
620 if (buffer.hasArray()) {
621 src = buffer.array();
622 sp = buffer.arrayOffset() + buffer.position();
623 sl = buffer.arrayOffset() + buffer.limit();
624 buffer.position(buffer.limit());
625 } else {
626 src = new byte[buffer.remaining()];
627 buffer.get(src);
628 sp = 0;
629 sl = src.length;
630 }
631 byte[] dst = new byte[outLength(src, sp, sl)];
632 return ByteBuffer.wrap(dst, 0, decode0(src, sp, sl, dst));
633 } catch (IllegalArgumentException iae) {
634 buffer.position(pos0);
635 throw iae;
636 }
637 }
638
639 /**
640 * Returns an input stream for decoding {@link Base64} encoded byte stream.
641 *
642 * <p> The {@code read} methods of the returned {@code InputStream} will
643 * throw {@code IOException} when reading bytes that cannot be decoded.
644 *
645 * <p> Closing the returned input stream will close the underlying
646 * input stream.
647 *
648 * @param is
649 * the input stream
650 *
651 * @return the input stream for decoding the specified Base64 encoded
652 * byte stream
653 */
654 public InputStream wrap(InputStream is) {
655 Objects.requireNonNull(is);
656 return new DecInputStream(is, isURL ? fromBase64URL : fromBase64, isMIME);
657 }
658
659 private int outLength(byte[] src, int sp, int sl) {
660 int[] base64 = isURL ? fromBase64URL : fromBase64;
661 int paddings = 0;
662 int len = sl - sp;
663 if (len == 0)
664 return 0;
665 if (len < 2) {
666 if (isMIME && base64[0] == -1)
667 return 0;
668 throw new IllegalArgumentException(
669 "Input byte[] should at least have 2 bytes for base64 bytes");
670 }
671 if (isMIME) {
672 // scan all bytes to fill out all non-alphabet. a performance
673 // trade-off of pre-scan or Arrays.copyOf
674 int n = 0;
675 while (sp < sl) {
676 int b = src[sp++] & 0xff;
677 if (b == '=') {
678 len -= (sl - sp + 1);
679 break;
680 }
681 if ((b = base64[b]) == -1)
682 n++;
683 }
684 len -= n;
685 } else {
686 if (src[sl - 1] == '=') {
687 paddings++;
688 if (src[sl - 2] == '=')
689 paddings++;
690 }
691 }
692 if (paddings == 0 && (len & 0x3) != 0)
693 paddings = 4 - (len & 0x3);
694 return 3 * ((len + 3) / 4) - paddings;
695 }
696
697 private int decode0(byte[] src, int sp, int sl, byte[] dst) {
698 int[] base64 = isURL ? fromBase64URL : fromBase64;
699 int dp = 0;
700 int bits = 0;
701 int shiftto = 18; // pos of first byte of 4-byte atom
702
703 while (sp < sl) {
704 if (shiftto == 18 && sp + 4 < sl) { // fast path
705 int sl0 = sp + ((sl - sp) & ~0b11);
706 while (sp < sl0) {
707 int b1 = base64[src[sp++] & 0xff];
708 int b2 = base64[src[sp++] & 0xff];
709 int b3 = base64[src[sp++] & 0xff];
710 int b4 = base64[src[sp++] & 0xff];
711 if ((b1 | b2 | b3 | b4) < 0) { // non base64 byte
712 sp -= 4;
713 break;
714 }
715 int bits0 = b1 << 18 | b2 << 12 | b3 << 6 | b4;
716 dst[dp++] = (byte)(bits0 >> 16);
717 dst[dp++] = (byte)(bits0 >> 8);
718 dst[dp++] = (byte)(bits0);
719 }
720 if (sp >= sl)
721 break;
722 }
723 int b = src[sp++] & 0xff;
724 if ((b = base64[b]) < 0) {
725 if (b == -2) { // padding byte '='
726 // = shiftto==18 unnecessary padding
727 // x= shiftto==12 a dangling single x
728 // x to be handled together with non-padding case
729 // xx= shiftto==6&&sp==sl missing last =
730 // xx=y shiftto==6 last is not =
731 if (shiftto == 6 && (sp == sl || src[sp++] != '=') ||
732 shiftto == 18) {
733 throw new IllegalArgumentException(
734 "Input byte array has wrong 4-byte ending unit");
735 }
736 break;
737 }
738 if (isMIME) // skip if for rfc2045
739 continue;
740 else
741 throw new IllegalArgumentException(
742 "Illegal base64 character " +
743 Integer.toString(src[sp - 1], 16));
744 }
745 bits |= (b << shiftto);
746 shiftto -= 6;
747 if (shiftto < 0) {
748 dst[dp++] = (byte)(bits >> 16);
749 dst[dp++] = (byte)(bits >> 8);
750 dst[dp++] = (byte)(bits);
751 shiftto = 18;
752 bits = 0;
753 }
754 }
755 // reached end of byte array or hit padding '=' characters.
756 if (shiftto == 6) {
757 dst[dp++] = (byte)(bits >> 16);
758 } else if (shiftto == 0) {
759 dst[dp++] = (byte)(bits >> 16);
760 dst[dp++] = (byte)(bits >> 8);
761 } else if (shiftto == 12) {
762 // dangling single "x", incorrectly encoded.
763 throw new IllegalArgumentException(
764 "Last unit does not have enough valid bits");
765 }
766 // anything left is invalid, if is not MIME.
767 // if MIME, ignore all non-base64 character
768 while (sp < sl) {
769 if (isMIME && base64[src[sp++] & 0xff] < 0)
770 continue;
771 throw new IllegalArgumentException(
772 "Input byte array has incorrect ending byte at " + sp);
773 }
774 return dp;
775 }
776 }
777
778 /*
779 * An output stream for encoding bytes into the Base64.
780 */
781 private static class EncOutputStream extends FilterOutputStream {
782
783 private int leftover = 0;
784 private int b0, b1, b2;
785 private boolean closed = false;
786
787 private final char[] base64; // byte->base64 mapping
788 private final byte[] newline; // line separator, if needed
789 private final int linemax;
790 private final boolean doPadding;// whether or not to pad
791 private int linepos = 0;
792 private byte[] buf;
793
794 EncOutputStream(OutputStream os, char[] base64,
795 byte[] newline, int linemax, boolean doPadding) {
796 super(os);
797 this.base64 = base64;
798 this.newline = newline;
799 this.linemax = linemax;
800 this.doPadding = doPadding;
801 this.buf = new byte[linemax <= 0 ? 8124 : linemax];
802 }
803
804 @Override
805 public void write(int b) throws IOException {
806 byte[] buf = new byte[1];
807 buf[0] = (byte)(b & 0xff);
808 write(buf, 0, 1);
809 }
810
811 private void checkNewline() throws IOException {
812 if (linepos == linemax) {
813 out.write(newline);
814 linepos = 0;
815 }
816 }
817
818 private void writeb4(char b1, char b2, char b3, char b4) throws IOException {
819 buf[0] = (byte)b1;
820 buf[1] = (byte)b2;
821 buf[2] = (byte)b3;
822 buf[3] = (byte)b4;
823 out.write(buf, 0, 4);
824 }
825
826 @Override
827 public void write(byte[] b, int off, int len) throws IOException {
828 if (closed)
829 throw new IOException("Stream is closed");
830 if (off < 0 || len < 0 || len > b.length - off)
831 throw new ArrayIndexOutOfBoundsException();
832 if (len == 0)
833 return;
834 if (leftover != 0) {
835 if (leftover == 1) {
836 b1 = b[off++] & 0xff;
837 len--;
838 if (len == 0) {
839 leftover++;
840 return;
841 }
842 }
843 b2 = b[off++] & 0xff;
844 len--;
845 checkNewline();
846 writeb4(base64[b0 >> 2],
847 base64[(b0 << 4) & 0x3f | (b1 >> 4)],
848 base64[(b1 << 2) & 0x3f | (b2 >> 6)],
849 base64[b2 & 0x3f]);
850 linepos += 4;
851 }
852 int nBits24 = len / 3;
853 leftover = len - (nBits24 * 3);
854
855 while (nBits24 > 0) {
856 checkNewline();
857 int dl = linemax <= 0 ? buf.length : buf.length - linepos;
858 int sl = off + Math.min(nBits24, dl / 4) * 3;
859 int dp = 0;
860 for (int sp = off; sp < sl; ) {
861 int bits = (b[sp++] & 0xff) << 16 |
862 (b[sp++] & 0xff) << 8 |
863 (b[sp++] & 0xff);
864 buf[dp++] = (byte)base64[(bits >>> 18) & 0x3f];
865 buf[dp++] = (byte)base64[(bits >>> 12) & 0x3f];
866 buf[dp++] = (byte)base64[(bits >>> 6) & 0x3f];
867 buf[dp++] = (byte)base64[bits & 0x3f];
868 }
869 out.write(buf, 0, dp);
870 off = sl;
871 linepos += dp;
872 nBits24 -= dp / 4;
873 }
874 if (leftover == 1) {
875 b0 = b[off++] & 0xff;
876 } else if (leftover == 2) {
877 b0 = b[off++] & 0xff;
878 b1 = b[off++] & 0xff;
879 }
880 }
881
882 @Override
883 public void close() throws IOException {
884 if (!closed) {
885 closed = true;
886 if (leftover == 1) {
887 checkNewline();
888 out.write(base64[b0 >> 2]);
889 out.write(base64[(b0 << 4) & 0x3f]);
890 if (doPadding) {
891 out.write('=');
892 out.write('=');
893 }
894 } else if (leftover == 2) {
895 checkNewline();
896 out.write(base64[b0 >> 2]);
897 out.write(base64[(b0 << 4) & 0x3f | (b1 >> 4)]);
898 out.write(base64[(b1 << 2) & 0x3f]);
899 if (doPadding) {
900 out.write('=');
901 }
902 }
903 leftover = 0;
904 out.close();
905 }
906 }
907 }
908
909 /*
910 * An input stream for decoding Base64 bytes
911 */
912 private static class DecInputStream extends InputStream {
913
914 private final InputStream is;
915 private final boolean isMIME;
916 private final int[] base64; // base64 -> byte mapping
917 private int bits = 0; // 24-bit buffer for decoding
918 private int nextin = 18; // next available "off" in "bits" for input;
919 // -> 18, 12, 6, 0
920 private int nextout = -8; // next available "off" in "bits" for output;
921 // -> 8, 0, -8 (no byte for output)
922 private boolean eof = false;
923 private boolean closed = false;
924
925 DecInputStream(InputStream is, int[] base64, boolean isMIME) {
926 this.is = is;
927 this.base64 = base64;
928 this.isMIME = isMIME;
929 }
930
931 private byte[] sbBuf = new byte[1];
932
933 @Override
934 public int read() throws IOException {
935 return read(sbBuf, 0, 1) == -1 ? -1 : sbBuf[0] & 0xff;
936 }
937
938 private int eof(byte[] b, int off, int len, int oldOff)
939 throws IOException
940 {
941 eof = true;
942 if (nextin != 18) {
943 if (nextin == 12)
944 throw new IOException("Base64 stream has one un-decoded dangling byte.");
945 // treat ending xx/xxx without padding character legal.
946 // same logic as v == '=' below
947 b[off++] = (byte)(bits >> (16));
948 if (nextin == 0) { // only one padding byte
949 if (len == 1) { // no enough output space
950 bits >>= 8; // shift to lowest byte
951 nextout = 0;
952 } else {
953 b[off++] = (byte) (bits >> 8);
954 }
955 }
956 }
957 return off == oldOff ? -1 : off - oldOff;
958 }
959
960 private int padding(byte[] b, int off, int len, int oldOff)
961 throws IOException
962 {
963 // = shiftto==18 unnecessary padding
964 // x= shiftto==12 dangling x, invalid unit
965 // xx= shiftto==6 && missing last '='
966 // xx=y or last is not '='
967 if (nextin == 18 || nextin == 12 ||
968 nextin == 6 && is.read() != '=') {
969 throw new IOException("Illegal base64 ending sequence:" + nextin);
970 }
971 b[off++] = (byte)(bits >> (16));
972 if (nextin == 0) { // only one padding byte
973 if (len == 1) { // no enough output space
974 bits >>= 8; // shift to lowest byte
975 nextout = 0;
976 } else {
977 b[off++] = (byte) (bits >> 8);
978 }
979 }
980 eof = true;
981 return off - oldOff;
982 }
983
984 @Override
985 public int read(byte[] b, int off, int len) throws IOException {
986 if (closed)
987 throw new IOException("Stream is closed");
988 if (eof && nextout < 0) // eof and no leftover
989 return -1;
990 if (off < 0 || len < 0 || len > b.length - off)
991 throw new IndexOutOfBoundsException();
992 int oldOff = off;
993 while (nextout >= 0) { // leftover output byte(s) in bits buf
994 if (len == 0)
995 return off - oldOff;
996 b[off++] = (byte)(bits >> nextout);
997 len--;
998 nextout -= 8;
999 }
1000 bits = 0;
1001 while (len > 0) {
1002 int v = is.read();
1003 if (v == -1) {
1004 return eof(b, off, len, oldOff);
1005 }
1006 if ((v = base64[v]) < 0) {
1007 if (v == -2) { // padding byte(s)
1008 return padding(b, off, len, oldOff);
1009 }
1010 if (v == -1) {
1011 if (!isMIME)
1012 throw new IOException("Illegal base64 character " +
1013 Integer.toString(v, 16));
1014 continue; // skip if for rfc2045
1015 }
1016 // neve be here
1017 }
1018 bits |= (v << nextin);
1019 if (nextin == 0) {
1020 nextin = 18; // clear for next in
1021 b[off++] = (byte)(bits >> 16);
1022 if (len == 1) {
1023 nextout = 8; // 2 bytes left in bits
1024 break;
1025 }
1026 b[off++] = (byte)(bits >> 8);
1027 if (len == 2) {
1028 nextout = 0; // 1 byte left in bits
1029 break;
1030 }
1031 b[off++] = (byte)bits;
1032 len -= 3;
1033 bits = 0;
1034 } else {
1035 nextin -= 6;
1036 }
1037 }
1038 return off - oldOff;
1039 }
1040
1041 @Override
1042 public int available() throws IOException {
1043 if (closed)
1044 throw new IOException("Stream is closed");
1045 return is.available(); // TBD:
1046 }
1047
1048 @Override
1049 public void close() throws IOException {
1050 if (!closed) {
1051 closed = true;
1052 is.close();
1053 }
1054 }
1055 }
1056 }