File Source: Base64.java
1 package net.miginfocom;
2
3 import java.util.Arrays;
4
5 /** A very fast and memory efficient class to encode and decode to and from BASE64 in full accordance
6 * with RFC 2045.<br><br>
7 * On Windows XP sp1 with 1.4.2_04 and later ;), this encoder and decoder is about 10 times faster
8 * on small arrays (10 - 1000 bytes) and 2-3 times as fast on larger arrays (10000 - 1000000 bytes)
9 * compared to <code>sun.misc.Encoder()/Decoder()</code>.<br><br>
10 *
11 * On byte arrays the encoder is about 20% faster than Jakarta Commons Base64 Codec for encode and
12 * about 50% faster for decoding large arrays. This implementation is about twice as fast on very small
13 * arrays (< 30 bytes). If source/destination is a <code>String</code> this
14 * version is about three times as fast due to the fact that the Commons Codec result has to be recoded
15 * to a <code>String</code> from <code>byte[]</code>, which is very expensive.<br><br>
16 *
17 * This encode/decode algorithm doesn't create any temporary arrays as many other codecs do, it only
18 * allocates the resulting array. This produces less garbage and it is possible to handle arrays twice
19 * as large as algorithms that create a temporary array. (E.g. Jakarta Commons Codec). It is unknown
20 * whether Sun's <code>sun.misc.Encoder()/Decoder()</code> produce temporary arrays but since performance
21 * is quite low it probably does.<br><br>
22 *
23 * The encoder produces the same output as the Sun one except that the Sun's encoder appends
24 * a trailing line separator if the last character isn't a pad. Unclear why but it only adds to the
25 * length and is probably a side effect. Both are in conformance with RFC 2045 though.<br>
26 * Commons codec seem to always att a trailing line separator.<br><br>
27 *
28 * <b>Note!</b>
29 * The encode/decode method pairs (types) come in three versions with the <b>exact</b> same algorithm and
30 * thus a lot of code redundancy. This is to not create any temporary arrays for transcoding to/from different
31 * format types. The methods not used can simply be commented out.<br><br>
32 *
33 * There is also a "fast" version of all decode methods that works the same way as the normal ones, but
34 * har a few demands on the decoded input. Normally though, these fast verions should be used if the source if
35 * the input is known and it hasn't bee tampered with.<br><br>
36 *
37 * If you find the code useful or you find a bug, please send me a note at base64 @ miginfocom . com.
38 *
39 * Licence (BSD):
40 * ==============
41 *
42 * Copyright (c) 2004, Mikael Grev, MiG InfoCom AB. (base64 @ miginfocom . com)
43 * All rights reserved.
44 *
45 * Redistribution and use in source and binary forms, with or without modification,
46 * are permitted provided that the following conditions are met:
47 * Redistributions of source code must retain the above copyright notice, this list
48 * of conditions and the following disclaimer.
49 * Redistributions in binary form must reproduce the above copyright notice, this
50 * list of conditions and the following disclaimer in the documentation and/or other
51 * materials provided with the distribution.
52 * Neither the name of the MiG InfoCom AB nor the names of its contributors may be
53 * used to endorse or promote products derived from this software without specific
54 * prior written permission.
55 *
56 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
57 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
58 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
59 * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
60 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
61 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
62 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
63 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
64 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
65 * OF SUCH DAMAGE.
66 *
67 * @version 2.2
68 * @author Mikael Grev
69 * Date: 2004-aug-02
70 * Time: 11:31:11
71 */
72
/*
P/P * Method: void net.miginfocom.Base64()
*/
73 public class Base64
74 {
/*
P/P * Method: net.miginfocom.Base64__static_init
*
* Presumptions:
* CA.length@75 <= 232-1
* CA[i]@75 <= 255
*
* Postconditions:
* CA != null
* IA == &new int[](Base64__static_init#1)
* new int[](Base64__static_init#1) num objects == 1
* IA.length == 256
* init'ed(IA[...])
* IA[61] == 0
*/
75 private static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
76 private static final int[] IA = new int[256];
77 static {
78 Arrays.fill(IA, -1);
79 for (int i = 0, iS = CA.length; i < iS; i++)
80 IA[CA[i]] = i;
81 IA['='] = 0;
82 }
83
84 // ****************************************************************************************
85 // * char[] version
86 // ****************************************************************************************
87
88 /** Encodes a raw byte array into a BASE64 <code>char[]</code> representation i accordance with RFC 2045.
89 * @param sArr The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
90 * @param lineSep Optional "\r\n" after 76 characters, unless end of file.<br>
91 * No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a
92 * little faster.
93 * @return A BASE64 encoded array. Never <code>null</code>.
94 */
95 public final static char[] encodeToChar(byte[] sArr, boolean lineSep)
96 {
97 // Check special case
/*
P/P * Method: char[] encodeToChar(byte[], bool)
*
* Preconditions:
* (soft) sArr.length in {0, 3..169_538_366}
* (soft) init'ed(sArr[...])
*
* Presumptions:
* (((sArr[(sLen - 1)] mod 256)*4) mod 232 | (sArr[eLen] mod 256)*1_024) mod 64 < java.lang.String:toCharArray(...)@75.length
* (sArr[s] | (sArr[s] mod 256)*216 | (sArr[s] mod 256)*256) mod 64 < java.lang.String:toCharArray(...)@75.length
* java.lang.String:toCharArray(...)@75.length >= 1
* init'ed(java.lang.String:toCharArray(...)@75[...])
* shr(((sArr[(sLen - 1)] mod 256)*4) mod 232 | (sArr[eLen] mod 256)*1_024, 12) < java.lang.String:toCharArray(...)@75.length
* ...
*
* Postconditions:
* return_value in Addr_Set{&new char[](encodeToChar#2),&new char[](encodeToChar#1)}
* new char[](encodeToChar#1) num objects <= 1
* new char[](encodeToChar#1).length == 0
* new char[](encodeToChar#2) num objects <= 1
* new char[](encodeToChar#2).length == (((One-of{sArr.length, 0} - 1)/3)*4 + 4) mod 232 + One-of{((((((One-of{sArr.length, 0} - 1)/3)*4 + 4) mod 232 - 1)/76)*2) mod 232, 0}
* new char[](encodeToChar#2).length in {4..231_999_870}
* possibly_updated(new char[](encodeToChar#2)[...])
*
* Test Vectors:
* lineSep: {0}, {1}
*/
98 int sLen = sArr != null ? sArr.length : 0;
99 if (sLen == 0)
100 return new char[0];
101
102 int eLen = (sLen / 3) * 3; // Length of even 24-bits.
103 int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count
104 int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of returned array
105 char[] dArr = new char[dLen];
106
107 // Encode even 24-bits
108 for (int s = 0, d = 0, cc = 0; s < eLen;) {
109 // Copy next three bytes into lower 24 bits of int, paying attension to sign.
110 int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8 | (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) | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);
131
132 // Set last four chars
133 dArr[dLen - 4] = CA[i >> 12];
134 dArr[dLen - 3] = CA[(i >>> 6) & 0x3f];
135 dArr[dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';
136 dArr[dLen - 1] = '=';
137 }
138 return dArr;
139 }
140
141 /** Decodes a BASE64 encoded char array. All illegal characters will be ignored and can handle both arrays with
142 * and without line separators.
143 * @param sArr The source array. <code>null</code> or length 0 will return an empty array.
144 * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
145 * (including '=') isn't divideable by 4. (I.e. definitely corrupted).
146 */
147 public final static byte[] decode(char[] sArr)
148 {
149 // Check special case
/*
P/P * Method: byte[] decode(char[])
*
* Preconditions:
* (soft) init'ed(IA[...])
* (soft) sArr.length <= 232-1
* (soft) sArr[...] <= 255
*
* Postconditions:
* return_value in Addr_Set{null,&new byte[](decode#2),&new byte[](decode#1)}
* new byte[](decode#1) num objects <= 1
* new byte[](decode#1).length == 0
* new byte[](decode#2) num objects <= 1
* new byte[](decode#2).length in {0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 129, 132, 135, 138, 141, 144, 147, 150, 153, 156, 159, 162, 165, 168, 171, 174, 177, 180, 183, 186, 189, 192, 195, 198, 201, 204, 207, 210, 213, 216, 219, 222, 225, 228, 231, 234, 237, 240, 243, 246, 249, 252, 255, 258, 261, 264, 267, 270, 273, 276, 279, 282, 285, 288, 291, 294, 297, 300, 303, 306, 309, 312, 315, 318, 321, 324, 327, 330..232-1}
* possibly_updated(new byte[](decode#2)[...])
*
* Test Vectors:
* IA[...]: {1..232-1}, {-231..-1}
* sArr[...]: {0..60, 62..255}, {61}
*/
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++) // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
158 if (IA[sArr[i]] < 0)
159 sepCnt++;
160
161 // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
162 if ((sLen - sepCnt) % 4 != 0)
163 return null;
164
165 int pad = 0;
166 for (int i = sLen; i > 1 && IA[sArr[--i]] <= 0;)
167 if (sArr[i] == '=')
168 pad++;
169
170 int len = ((sLen - sepCnt) * 6 >> 3) - pad;
171
172 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
173
174 for (int s = 0, d = 0; d < len;) {
175 // Assemble three bytes into an int from four "valid" characters.
176 int i = 0;
177 for (int j = 0; j < 4; j++) { // j only increased if a valid char was found.
178 int c = IA[sArr[s++]];
179 if (c >= 0)
180 i |= c << (18 - j * 6);
181 else
182 j--;
183 }
184 // Add the bytes
185 dArr[d++] = (byte) (i >> 16);
186 if (d < len) {
187 dArr[d++]= (byte) (i >> 8);
188 if (d < len)
189 dArr[d++] = (byte) i;
190 }
191 }
192 return dArr;
193 }
194
195 /** Decodes a BASE64 encoded char array that is known to be resonably well formatted. The method is about twice as
196 * fast as {@link #decode(char[])}. The preconditions are:<br>
197 * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
198 * + Line separator must be "\r\n", as specified in RFC 2045
199 * + The array must not contain illegal characters within the encoded string<br>
200 * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
201 * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
202 * @return The decoded array of bytes. May be of length 0.
203 */
204 public final static byte[] decodeFast(char[] sArr)
205 {
206 // Check special case
/*
P/P * Method: byte[] decodeFast(char[])
*
* Preconditions:
* sArr != null
* sArr.length in {0, 4..232-1}
* (soft) init'ed(IA[...])
* (soft) sArr[...] <= 255
* (soft) sArr[76] <= 255
*
* Postconditions:
* return_value in Addr_Set{&new byte[](decodeFast#2),&new byte[](decodeFast#1)}
* new byte[](decodeFast#1) num objects <= 1
* new byte[](decodeFast#1).length == 0
* new byte[](decodeFast#2) num objects <= 1
* new byte[](decodeFast#2).length <= 231
* possibly_updated(new byte[](decodeFast#2)[...])
*
* Test Vectors:
* IA[...]: {0..232-1}, {-231..-1}
* sArr.length: {77..232-1}, {0}
*/
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 : 0;
225
226 int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
227 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
228
229 // Decode all but the last 0 - 2 bytes.
230 int d = 0;
231 for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
232 // Assemble three bytes into an int from four "valid" characters.
233 int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12 | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];
234
235 // Add the bytes
236 dArr[d++] = (byte) (i >> 16);
237 dArr[d++] = (byte) (i >> 8);
238 dArr[d++] = (byte) i;
239
240 // If line separator, jump over it.
241 if (sepCnt > 0 && ++cc == 19) {
242 sIx += 2;
243 cc = 0;
244 }
245 }
246
247 if (d < len) {
248 // Decode last 1-3 bytes (incl '=') into 1-3 bytes
249 int i = 0;
250 for (int j = 0; sIx <= eIx - pad; j++)
251 i |= IA[sArr[sIx++]] << (18 - j * 6);
252
253 for (int r = 16; d < len; r -= 8)
254 dArr[d++] = (byte) (i >> r);
255 }
256
257 return dArr;
258 }
259
260 // ****************************************************************************************
261 // * byte[] version
262 // ****************************************************************************************
263
264 /** Encodes a raw byte array into a BASE64 <code>byte[]</code> representation i accordance with RFC 2045.
265 * @param sArr The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
266 * @param lineSep Optional "\r\n" after 76 characters, unless end of file.<br>
267 * No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a
268 * little faster.
269 * @return A BASE64 encoded array. Never <code>null</code>.
270 */
271 public final static byte[] encodeToByte(byte[] sArr, boolean lineSep)
272 {
273 // Check special case
/*
P/P * Method: byte[] encodeToByte(byte[], bool)
*
* Preconditions:
* (soft) sArr.length in {0, 3..132_343_121}
* (soft) init'ed(sArr[...])
*
* Presumptions:
* (((sArr[(sLen - 1)] mod 256)*4) mod 232 | (sArr[eLen] mod 256)*1_024) mod 64 < java.lang.String:toCharArray(...)@75.length
* (sArr[s] | (sArr[s] mod 256)*216 | (sArr[s] mod 256)*256) mod 64 < java.lang.String:toCharArray(...)@75.length
* java.lang.String:toCharArray(...)@75.length >= 1
* init'ed(java.lang.String:toCharArray(...)@75[...])
* shr(((sArr[(sLen - 1)] mod 256)*4) mod 232 | (sArr[eLen] mod 256)*1_024, 12) < java.lang.String:toCharArray(...)@75.length
* ...
*
* Postconditions:
* return_value in Addr_Set{&new byte[](encodeToByte#2),&new byte[](encodeToByte#1)}
* new byte[](encodeToByte#1) num objects <= 1
* new byte[](encodeToByte#1).length == 0
* new byte[](encodeToByte#2) num objects <= 1
* new byte[](encodeToByte#2).length == (((One-of{sArr.length, 0} - 1)/3)*4 + 4) mod 232 + One-of{((((((One-of{sArr.length, 0} - 1)/3)*4 + 4) mod 232 - 1)/76)*2) mod 232, 0}
* new byte[](encodeToByte#2).length in {4..181_101_114}
* possibly_updated(new byte[](encodeToByte#2)[...])
*
* Test Vectors:
* lineSep: {0}, {1}
*/
274 int sLen = sArr != null ? sArr.length : 0;
275 if (sLen == 0)
276 return new byte[0];
277
278 int eLen = (sLen / 3) * 3; // Length of even 24-bits.
279 int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count
280 int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of returned array
281 byte[] dArr = new byte[dLen];
282
283 // Encode even 24-bits
284 for (int s = 0, d = 0, cc = 0; s < eLen;) {
285 // Copy next three bytes into lower 24 bits of int, paying attension to sign.
286 int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8 | (sArr[s++] & 0xff);
287
288 // Encode the int into four chars
289 dArr[d++] = (byte) CA[(i >>> 18) & 0x3f];
290 dArr[d++] = (byte) CA[(i >>> 12) & 0x3f];
291 dArr[d++] = (byte) CA[(i >>> 6) & 0x3f];
292 dArr[d++] = (byte) CA[i & 0x3f];
293
294 // Add optional line separator
295 if (lineSep && ++cc == 19 && d < dLen - 2) {
296 dArr[d++] = '\r';
297 dArr[d++] = '\n';
298 cc = 0;
299 }
300 }
301
302 // Pad and encode last bits if source isn't an even 24 bits.
303 int left = sLen - eLen; // 0 - 2.
304 if (left > 0) {
305 // Prepare the int
306 int i = ((sArr[eLen] & 0xff) << 10) | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);
307
308 // Set last four chars
309 dArr[dLen - 4] = (byte) CA[i >> 12];
310 dArr[dLen - 3] = (byte) CA[(i >>> 6) & 0x3f];
311 dArr[dLen - 2] = left == 2 ? (byte) CA[i & 0x3f] : (byte) '=';
312 dArr[dLen - 1] = '=';
313 }
314 return dArr;
315 }
316
317 /** Decodes a BASE64 encoded byte array. All illegal characters will be ignored and can handle both arrays with
318 * and without line separators.
319 * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
320 * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
321 * (including '=') isn't divideable by 4. (I.e. definitely corrupted).
322 */
323 public final static byte[] decode(byte[] sArr)
324 {
325 // Check special case
/*
P/P * Method: byte[] decode(byte[])
*
* Preconditions:
* sArr != null
* (soft) init'ed(IA[...])
* (soft) sArr.length in {1..232-1}
* (soft) init'ed(sArr[...])
*
* Postconditions:
* return_value in Addr_Set{null,&new byte[](decode#1)}
* new byte[](decode#1) num objects <= 1
* new byte[](decode#1).length in {0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 129, 132, 135, 138, 141, 144, 147, 150, 153, 156, 159, 162, 165, 168, 171, 174, 177, 180, 183, 186, 189, 192, 195, 198, 201, 204, 207, 210, 213, 216, 219, 222, 225, 228, 231, 234, 237, 240, 243, 246, 249, 252, 255, 258, 261, 264, 267, 270, 273, 276, 279, 282, 285, 288, 291, 294, 297, 300, 303, 306, 309, 312, 315, 318, 321, 324, 327, 330..232-1}
* possibly_updated(new byte[](decode#1)[...])
*
* Test Vectors:
* IA[...]: {1..232-1}, {-231..-1}
* sArr[...]: {-128..60, 62..255}, {61}
*/
326 int sLen = sArr.length;
327
328 // Count illegal characters (including '\r', '\n') to know what size the returned array will be,
329 // so we don't have to reallocate & copy it later.
330 int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)
331 for (int i = 0; i < sLen; i++) // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
332 if (IA[sArr[i] & 0xff] < 0)
333 sepCnt++;
334
335 // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
336 if ((sLen - sepCnt) % 4 != 0)
337 return null;
338
339 int pad = 0;
340 for (int i = sLen; i > 1 && IA[sArr[--i] & 0xff] <= 0;)
341 if (sArr[i] == '=')
342 pad++;
343
344 int len = ((sLen - sepCnt) * 6 >> 3) - pad;
345
346 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
347
348 for (int s = 0, d = 0; d < len;) {
349 // Assemble three bytes into an int from four "valid" characters.
350 int i = 0;
351 for (int j = 0; j < 4; j++) { // j only increased if a valid char was found.
352 int c = IA[sArr[s++] & 0xff];
353 if (c >= 0)
354 i |= c << (18 - j * 6);
355 else
356 j--;
357 }
358
359 // Add the bytes
360 dArr[d++] = (byte) (i >> 16);
361 if (d < len) {
362 dArr[d++]= (byte) (i >> 8);
363 if (d < len)
364 dArr[d++] = (byte) i;
365 }
366 }
367
368 return dArr;
369 }
370
371
372 /** Decodes a BASE64 encoded byte array that is known to be resonably well formatted. The method is about twice as
373 * fast as {@link #decode(byte[])}. The preconditions are:<br>
374 * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
375 * + Line separator must be "\r\n", as specified in RFC 2045
376 * + The array must not contain illegal characters within the encoded string<br>
377 * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
378 * @param sArr The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
379 * @return The decoded array of bytes. May be of length 0.
380 */
381 public final static byte[] decodeFast(byte[] sArr)
382 {
383 // Check special case
/*
P/P * Method: byte[] decodeFast(byte[])
*
* Preconditions:
* sArr != null
* sArr.length in {0, 4..232-1}
* (soft) init'ed(IA[...])
* (soft) sArr[...] >= 0
* (soft) sArr[76] >= 0
*
* Postconditions:
* return_value in Addr_Set{&new byte[](decodeFast#2),&new byte[](decodeFast#1)}
* new byte[](decodeFast#1) num objects <= 1
* new byte[](decodeFast#1).length == 0
* new byte[](decodeFast#2) num objects <= 1
* new byte[](decodeFast#2).length <= 231
* possibly_updated(new byte[](decodeFast#2)[...])
*
* Test Vectors:
* IA[...]: {0..232-1}, {-231..-1}
* sArr.length: {77..232-1}, {0}
*/
384 int sLen = sArr.length;
385 if (sLen == 0)
386 return new byte[0];
387
388 int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
389
390 // Trim illegal chars from start
391 while (sIx < eIx && IA[sArr[sIx] & 0xff] < 0)
392 sIx++;
393
394 // Trim illegal chars from end
395 while (eIx > 0 && IA[sArr[eIx] & 0xff] < 0)
396 eIx--;
397
398 // get the padding count (=) (0, 1 or 2)
399 int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count '=' at end.
400 int cCnt = eIx - sIx + 1; // Content count including possible separators
401 int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;
402
403 int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
404 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
405
406 // Decode all but the last 0 - 2 bytes.
407 int d = 0;
408 for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
409 // Assemble three bytes into an int from four "valid" characters.
410 int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12 | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];
411
412 // Add the bytes
413 dArr[d++] = (byte) (i >> 16);
414 dArr[d++] = (byte) (i >> 8);
415 dArr[d++] = (byte) i;
416
417 // If line separator, jump over it.
418 if (sepCnt > 0 && ++cc == 19) {
419 sIx += 2;
420 cc = 0;
421 }
422 }
423
424 if (d < len) {
425 // Decode last 1-3 bytes (incl '=') into 1-3 bytes
426 int i = 0;
427 for (int j = 0; sIx <= eIx - pad; j++)
428 i |= IA[sArr[sIx++]] << (18 - j * 6);
429
430 for (int r = 16; d < len; r -= 8)
431 dArr[d++] = (byte) (i >> r);
432 }
433
434 return dArr;
435 }
436
437 // ****************************************************************************************
438 // * String version
439 // ****************************************************************************************
440
441 /** Encodes a raw byte array into a BASE64 <code>String</code> representation i accordance with RFC 2045.
442 * @param sArr The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
443 * @param lineSep Optional "\r\n" after 76 characters, unless end of file.<br>
444 * No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a
445 * little faster.
446 * @return A BASE64 encoded array. Never <code>null</code>.
447 */
448 public final static String encodeToString(byte[] sArr, boolean lineSep)
449 {
450 // Reuse char[] since we can't create a String incrementally anyway and StringBuffer/Builder would be slower.
/*
P/P * Method: String encodeToString(byte[], bool)
*
* Preconditions:
* (soft) sArr.length in {0, 3..169_538_366}
* (soft) init'ed(sArr[...])
*
* Postconditions:
* return_value == &new String(encodeToString#1)
* new String(encodeToString#1) num objects == 1
*/
451 return new String(encodeToChar(sArr, lineSep));
452 }
453
454 /** Decodes a BASE64 encoded <code>String</code>. All illegal characters will be ignored and can handle both strings with
455 * and without line separators.<br>
456 * <b>Note!</b> It can be up to about 2x the speed to call <code>decode(str.toCharArray())</code> instead. That
457 * will create a temporary array though. This version will use <code>str.charAt(i)</code> to iterate the string.
458 * @param str The source string. <code>null</code> or length 0 will return an empty array.
459 * @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
460 * (including '=') isn't divideable by 4. (I.e. definitely corrupted).
461 */
462 public final static byte[] decode(String str)
463 {
464 // Check special case
/*
P/P * Method: byte[] decode(String)
*
* Preconditions:
* (soft) init'ed(IA[...])
*
* Presumptions:
* java.lang.String:charAt(...)@473 <= 255
* java.lang.String:charAt(...)@482 <= 255
* java.lang.String:charAt(...)@494 <= 255
*
* Postconditions:
* return_value in Addr_Set{null,&new byte[](decode#2),&new byte[](decode#1)}
* new byte[](decode#1) num objects <= 1
* new byte[](decode#1).length == 0
* new byte[](decode#2) num objects <= 1
* new byte[](decode#2).length in {0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 129, 132, 135, 138, 141, 144, 147, 150, 153, 156, 159, 162, 165, 168, 171, 174, 177, 180, 183, 186, 189, 192, 195, 198, 201, 204, 207, 210, 213, 216, 219, 222, 225, 228, 231, 234, 237, 240, 243, 246, 249, 252, 255, 258, 261, 264, 267, 270, 273, 276, 279, 282, 285, 288, 291, 294, 297, 300, 303, 306, 309, 312, 315, 318, 321, 324, 327, 330..232-1}
* possibly_updated(new byte[](decode#2)[...])
*
* Test Vectors:
* IA[...]: {1..232-1}, {-231..-1}
* java.lang.String:charAt(...)@483: {0..60, 62..216-1}, {61}
*/
465 int sLen = str != null ? str.length() : 0;
466 if (sLen == 0)
467 return new byte[0];
468
469 // Count illegal characters (including '\r', '\n') to know what size the returned array will be,
470 // so we don't have to reallocate & copy it later.
471 int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)
472 for (int i = 0; i < sLen; i++) // If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
473 if (IA[str.charAt(i)] < 0)
474 sepCnt++;
475
476 // Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
477 if ((sLen - sepCnt) % 4 != 0)
478 return null;
479
480 // Count '=' at end
481 int pad = 0;
482 for (int i = sLen; i > 1 && IA[str.charAt(--i)] <= 0;)
483 if (str.charAt(i) == '=')
484 pad++;
485
486 int len = ((sLen - sepCnt) * 6 >> 3) - pad;
487
488 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
489
490 for (int s = 0, d = 0; d < len;) {
491 // Assemble three bytes into an int from four "valid" characters.
492 int i = 0;
493 for (int j = 0; j < 4; j++) { // j only increased if a valid char was found.
494 int c = IA[str.charAt(s++)];
495 if (c >= 0)
496 i |= c << (18 - j * 6);
497 else
498 j--;
499 }
500 // Add the bytes
501 dArr[d++] = (byte) (i >> 16);
502 if (d < len) {
503 dArr[d++]= (byte) (i >> 8);
504 if (d < len)
505 dArr[d++] = (byte) i;
506 }
507 }
508 return dArr;
509 }
510
511 /** Decodes a BASE64 encoded string that is known to be resonably well formatted. The method is about twice as
512 * fast as {@link #decode(String)}. The preconditions are:<br>
513 * + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
514 * + Line separator must be "\r\n", as specified in RFC 2045
515 * + The array must not contain illegal characters within the encoded string<br>
516 * + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
517 * @param s The source string. Length 0 will return an empty array. <code>null</code> will throw an exception.
518 * @return The decoded array of bytes. May be of length 0.
519 */
520 public final static byte[] decodeFast(String s)
521 {
522 // Check special case
/*
P/P * Method: byte[] decodeFast(String)
*
* Preconditions:
* s != null
* (soft) init'ed(IA[...])
*
* Presumptions:
* java.lang.String:charAt(...)@549 <= 255
* java.lang.String:charAt(...)@567 <= 255
* java.lang.String:length(...)@523 not in {1..3}
*
* Postconditions:
* return_value in Addr_Set{&new byte[](decodeFast#2),&new byte[](decodeFast#1)}
* new byte[](decodeFast#1) num objects <= 1
* new byte[](decodeFast#1).length == 0
* new byte[](decodeFast#2) num objects <= 1
* new byte[](decodeFast#2).length <= 231
* possibly_updated(new byte[](decodeFast#2)[...])
*
* Test Vectors:
* IA[...]: {0..232-1}, {-231..-1}
* java.lang.String:length(...)@523: {77..232-1}, {0}
*/
523 int sLen = s.length();
524 if (sLen == 0)
525 return new byte[0];
526
527 int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
528
529 // Trim illegal chars from start
530 while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0)
531 sIx++;
532
533 // Trim illegal chars from end
534 while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0)
535 eIx--;
536
537 // get the padding count (=) (0, 1 or 2)
538 int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2 : 1) : 0; // Count '=' at end.
539 int cCnt = eIx - sIx + 1; // Content count including possible separators
540 int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1 : 0;
541
542 int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
543 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
544
545 // Decode all but the last 0 - 2 bytes.
546 int d = 0;
547 for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {
548 // Assemble three bytes into an int from four "valid" characters.
549 int i = IA[s.charAt(sIx++)] << 18 | IA[s.charAt(sIx++)] << 12 | IA[s.charAt(sIx++)] << 6 | IA[s.charAt(sIx++)];
550
551 // Add the bytes
552 dArr[d++] = (byte) (i >> 16);
553 dArr[d++] = (byte) (i >> 8);
554 dArr[d++] = (byte) i;
555
556 // If line separator, jump over it.
557 if (sepCnt > 0 && ++cc == 19) {
558 sIx += 2;
559 cc = 0;
560 }
561 }
562
563 if (d < len) {
564 // Decode last 1-3 bytes (incl '=') into 1-3 bytes
565 int i = 0;
566 for (int j = 0; sIx <= eIx - pad; j++)
567 i |= IA[s.charAt(sIx++)] << (18 - j * 6);
568
569 for (int r = 16; d < len; r -= 8)
570 dArr[d++] = (byte) (i >> r);
571 }
572
573 return dArr;
574 }
575 }
SofCheck Inspector Build Version : 2.17854
| Base64.java |
2009-Jun-25 01:54:24 |
| Base64.class |
2009-Sep-02 17:04:17 |