1 package org.itracker.services.util;
2 /**
3 * A Base64 Encoder/Decoder.
4 *
5 * <p>
6 * This class is used to encode and decode data in Base64 format as described in RFC 1521.
7 *
8 * <p>
9 * This is "Open Source" software and released under the <a href="http://www.gnu.org/licenses/lgpl.html">GNU/LGPL</a> license.<br>
10 * It is provided "as is" without warranty of any kind.<br>
11 * Copyright 2003: Christian d'Heureuse, Inventec Informatik AG, Switzerland.<br>
12 * Home page: <a href="http://www.source-code.biz">www.source-code.biz</a><br>
13 *
14 * <p>
15 * Version history:<br>
16 * 2003-07-22 Christian d'Heureuse (chdh): Module created.<br>
17 * 2005-08-11 chdh: Lincense changed from GPL to LGPL.<br>
18 * 2006-11-21 chdh:<br>
19 * Method encode(String) renamed to encodeString(String).<br>
20 * Method decode(String) renamed to decodeString(String).<br>
21 * New method encode(byte[],int) added.<br>
22 * New method decode(String) added.<br>
23 */
24
25 public class Base64Coder {
26
27 // Mapping table from 6-bit nibbles to Base64 characters.
28 private static char[] map1 = new char[64];
29 static {
30 int i=0;
31 for (char c='A'; c<='Z'; c++) map1[i++] = c;
32 for (char c='a'; c<='z'; c++) map1[i++] = c;
33 for (char c='0'; c<='9'; c++) map1[i++] = c;
34 map1[i++] = '+'; map1[i++] = '/'; }
35
36 // Mapping table from Base64 characters to 6-bit nibbles.
37 private static byte[] map2 = new byte[128];
38 static {
39 for (int i=0; i<map2.length; i++) map2[i] = -1;
40 for (int i=0; i<64; i++) map2[map1[i]] = (byte)i; }
41
42 /**
43 * Encodes a string into Base64 format.
44 * No blanks or line breaks are inserted.
45 * @param s a String to be encoded.
46 * @return A String with the Base64 encoded data.
47 */
48 public static String encodeString (String s) {
49 return new String(encode(s.getBytes())); }
50
51 /**
52 * Encodes a byte array into Base64 format.
53 * No blanks or line breaks are inserted.
54 * @param in an array containing the data bytes to be encoded.
55 * @return A character array with the Base64 encoded data.
56 */
57 public static char[] encode (byte[] in) {
58 return encode(in,in.length); }
59
60 /**
61 * Encodes a byte array into Base64 format.
62 * No blanks or line breaks are inserted.
63 * @param in an array containing the data bytes to be encoded.
64 * @param iLen number of bytes to process in <code>in</code>.
65 * @return A character array with the Base64 encoded data.
66 */
67 public static char[] encode (byte[] in, int iLen) {
68 int oDataLen = (iLen*4+2)/3; // output length without padding
69 int oLen = ((iLen+2)/3)*4; // output length including padding
70 char[] out = new char[oLen];
71 int ip = 0;
72 int op = 0;
73 while (ip < iLen) {
74 int i0 = in[ip++] & 0xff;
75 int i1 = ip < iLen ? in[ip++] & 0xff : 0;
76 int i2 = ip < iLen ? in[ip++] & 0xff : 0;
77 int o0 = i0 >>> 2;
78 int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
79 int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
80 int o3 = i2 & 0x3F;
81 out[op++] = map1[o0];
82 out[op++] = map1[o1];
83 out[op] = op < oDataLen ? map1[o2] : '='; op++;
84 out[op] = op < oDataLen ? map1[o3] : '='; op++; }
85 return out; }
86
87 /**
88 * Decodes a string from Base64 format.
89 * @param s a Base64 String to be decoded.
90 * @return A String containing the decoded data.
91 * @throws IllegalArgumentException if the input is not valid Base64 encoded data.
92 */
93 public static String decodeString (String s) {
94 return new String(decode(s)); }
95
96 /**
97 * Decodes a byte array from Base64 format.
98 * @param s a Base64 String to be decoded.
99 * @return An array containing the decoded data bytes.
100 * @throws IllegalArgumentException if the input is not valid Base64 encoded data.
101 */
102 public static byte[] decode (String s) {
103 return decode(s.toCharArray()); }
104
105 /**
106 * Decodes a byte array from Base64 format.
107 * No blanks or line breaks are allowed within the Base64 encoded data.
108 * @param in a character array containing the Base64 encoded data.
109 * @return An array containing the decoded data bytes.
110 * @throws IllegalArgumentException if the input is not valid Base64 encoded data.
111 */
112 public static byte[] decode (char[] in) {
113 int iLen = in.length;
114 if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");
115 while (iLen > 0 && in[iLen-1] == '=') iLen--;
116 int oLen = (iLen*3) / 4;
117 byte[] out = new byte[oLen];
118 int ip = 0;
119 int op = 0;
120 while (ip < iLen) {
121 int i0 = in[ip++];
122 int i1 = in[ip++];
123 int i2 = ip < iLen ? in[ip++] : 'A';
124 int i3 = ip < iLen ? in[ip++] : 'A';
125 if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
126 throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
127 int b0 = map2[i0];
128 int b1 = map2[i1];
129 int b2 = map2[i2];
130 int b3 = map2[i3];
131 if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
132 throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
133 int o0 = ( b0 <<2) | (b1>>>4);
134 int o1 = ((b1 & 0xf)<<4) | (b2>>>2);
135 int o2 = ((b2 & 3)<<6) | b3;
136 out[op++] = (byte)o0;
137 if (op<oLen) out[op++] = (byte)o1;
138 if (op<oLen) out[op++] = (byte)o2; }
139 return out; }
140
141 // Dummy constructor.
142 private Base64Coder() {}
143
144 } // end class Base64Coder