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b86bc4cf | 1 | package com.easysw.cups; |
2 | ||
3 | /** | |
4 | * A Base64 Encoder/Decoder. | |
5 | * | |
6 | * <p> | |
7 | * This class is used to encode and decode data in Base64 format as described in RFC 1521. | |
8 | * | |
9 | * <p> | |
10 | * This is "Open Source" software and released under the <a href="http://www.gnu.org/licenses/lgpl.html">GNU/LGPL</a> license.<br> | |
11 | * It is provided "as is" without warranty of any kind.<br> | |
12 | * Copyright 2003: Christian d'Heureuse, Inventec Informatik AG, Switzerland.<br> | |
13 | * Home page: <a href="http://www.source-code.biz">www.source-code.biz</a><br> | |
14 | * | |
15 | * <p> | |
16 | * Version history:<br> | |
17 | * 2003-07-22 Christian d'Heureuse (chdh): Module created.<br> | |
18 | * 2005-08-11 chdh: Lincense changed from GPL to LGPL.<br> | |
19 | * 2006-11-21 chdh:<br> | |
20 | * Method encode(String) renamed to encodeString(String).<br> | |
21 | * Method decode(String) renamed to decodeString(String).<br> | |
22 | * New method encode(byte[],int) added.<br> | |
23 | * New method decode(String) added.<br> | |
24 | */ | |
25 | ||
26 | public class Base64Coder { | |
27 | ||
28 | // Mapping table from 6-bit nibbles to Base64 characters. | |
29 | private static char[] map1 = new char[64]; | |
30 | static { | |
31 | int i=0; | |
32 | for (char c='A'; c<='Z'; c++) map1[i++] = c; | |
33 | for (char c='a'; c<='z'; c++) map1[i++] = c; | |
34 | for (char c='0'; c<='9'; c++) map1[i++] = c; | |
35 | map1[i++] = '+'; map1[i++] = '/'; } | |
36 | ||
37 | // Mapping table from Base64 characters to 6-bit nibbles. | |
38 | private static byte[] map2 = new byte[128]; | |
39 | static { | |
40 | for (int i=0; i<map2.length; i++) map2[i] = -1; | |
41 | for (int i=0; i<64; i++) map2[map1[i]] = (byte)i; } | |
42 | ||
43 | /** | |
44 | * Encodes a string into Base64 format. | |
45 | * No blanks or line breaks are inserted. | |
46 | * @param s a String to be encoded. | |
47 | * @return A String with the Base64 encoded data. | |
48 | */ | |
49 | public static String encodeString (String s) { | |
50 | return new String(encode(s.getBytes())); } | |
51 | ||
52 | /** | |
53 | * Encodes a byte array into Base64 format. | |
54 | * No blanks or line breaks are inserted. | |
55 | * @param in an array containing the data bytes to be encoded. | |
56 | * @return A character array with the Base64 encoded data. | |
57 | */ | |
58 | public static char[] encode (byte[] in) { | |
59 | return encode(in,in.length); } | |
60 | ||
61 | /** | |
62 | * Encodes a byte array into Base64 format. | |
63 | * No blanks or line breaks are inserted. | |
64 | * @param in an array containing the data bytes to be encoded. | |
65 | * @param iLen number of bytes to process in <code>in</code>. | |
66 | * @return A character array with the Base64 encoded data. | |
67 | */ | |
68 | public static char[] encode (byte[] in, int iLen) { | |
69 | int oDataLen = (iLen*4+2)/3; // output length without padding | |
70 | int oLen = ((iLen+2)/3)*4; // output length including padding | |
71 | char[] out = new char[oLen]; | |
72 | int ip = 0; | |
73 | int op = 0; | |
74 | while (ip < iLen) { | |
75 | int i0 = in[ip++] & 0xff; | |
76 | int i1 = ip < iLen ? in[ip++] & 0xff : 0; | |
77 | int i2 = ip < iLen ? in[ip++] & 0xff : 0; | |
78 | int o0 = i0 >>> 2; | |
79 | int o1 = ((i0 & 3) << 4) | (i1 >>> 4); | |
80 | int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6); | |
81 | int o3 = i2 & 0x3F; | |
82 | out[op++] = map1[o0]; | |
83 | out[op++] = map1[o1]; | |
84 | out[op] = op < oDataLen ? map1[o2] : '='; op++; | |
85 | out[op] = op < oDataLen ? map1[o3] : '='; op++; } | |
86 | return out; } | |
87 | ||
88 | /** | |
89 | * Decodes a string from Base64 format. | |
90 | * @param s a Base64 String to be decoded. | |
91 | * @return A String containing the decoded data. | |
92 | * @throws IllegalArgumentException if the input is not valid Base64 encoded data. | |
93 | */ | |
94 | public static String decodeString (String s) { | |
95 | return new String(decode(s)); } | |
96 | ||
97 | /** | |
98 | * Decodes a byte array from Base64 format. | |
99 | * @param s a Base64 String to be decoded. | |
100 | * @return An array containing the decoded data bytes. | |
101 | * @throws IllegalArgumentException if the input is not valid Base64 encoded data. | |
102 | */ | |
103 | public static byte[] decode (String s) { | |
104 | return decode(s.toCharArray()); } | |
105 | ||
106 | /** | |
107 | * Decodes a byte array from Base64 format. | |
108 | * No blanks or line breaks are allowed within the Base64 encoded data. | |
109 | * @param in a character array containing the Base64 encoded data. | |
110 | * @return An array containing the decoded data bytes. | |
111 | * @throws IllegalArgumentException if the input is not valid Base64 encoded data. | |
112 | */ | |
113 | public static byte[] decode (char[] in) { | |
114 | int iLen = in.length; | |
115 | if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4."); | |
116 | while (iLen > 0 && in[iLen-1] == '=') iLen--; | |
117 | int oLen = (iLen*3) / 4; | |
118 | byte[] out = new byte[oLen]; | |
119 | int ip = 0; | |
120 | int op = 0; | |
121 | while (ip < iLen) { | |
122 | int i0 = in[ip++]; | |
123 | int i1 = in[ip++]; | |
124 | int i2 = ip < iLen ? in[ip++] : 'A'; | |
125 | int i3 = ip < iLen ? in[ip++] : 'A'; | |
126 | if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127) | |
127 | throw new IllegalArgumentException ("Illegal character in Base64 encoded data."); | |
128 | int b0 = map2[i0]; | |
129 | int b1 = map2[i1]; | |
130 | int b2 = map2[i2]; | |
131 | int b3 = map2[i3]; | |
132 | if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0) | |
133 | throw new IllegalArgumentException ("Illegal character in Base64 encoded data."); | |
134 | int o0 = ( b0 <<2) | (b1>>>4); | |
135 | int o1 = ((b1 & 0xf)<<4) | (b2>>>2); | |
136 | int o2 = ((b2 & 3)<<6) | b3; | |
137 | out[op++] = (byte)o0; | |
138 | if (op<oLen) out[op++] = (byte)o1; | |
139 | if (op<oLen) out[op++] = (byte)o2; } | |
140 | return out; } | |
141 | ||
142 | // Dummy constructor. | |
143 | private Base64Coder() {} | |
144 | ||
145 | } // end class Base64Coder |