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comparison src/ch/ethz/ssh2/crypto/Base64.java @ 273:91a31873c42a ganymed

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start conversion from trilead to ganymed
author Carl Byington <carl@five-ten-sg.com>
date Fri, 18 Jul 2014 11:21:46 -0700
parents
children 071eccdff8ea
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272:ce2f4e397703 273:91a31873c42a
1 /*
2 * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
3 * Please refer to the LICENSE.txt for licensing details.
4 */
5 package ch.ethz.ssh2.crypto;
6
7 import java.io.CharArrayWriter;
8 import java.io.IOException;
9
10 /**
11 * Basic Base64 Support.
12 *
13 * @author Christian Plattner
14 * @version 2.50, 03/15/10
15 */
16 public class Base64
17 {
18 static final char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
19
20 public static char[] encode(byte[] content)
21 {
22 CharArrayWriter cw = new CharArrayWriter((4 * content.length) / 3);
23
24 int idx = 0;
25
26 int x = 0;
27
28 for (int i = 0; i < content.length; i++)
29 {
30 if (idx == 0)
31 x = (content[i] & 0xff) << 16;
32 else if (idx == 1)
33 x = x | ((content[i] & 0xff) << 8);
34 else
35 x = x | (content[i] & 0xff);
36
37 idx++;
38
39 if (idx == 3)
40 {
41 cw.write(alphabet[x >> 18]);
42 cw.write(alphabet[(x >> 12) & 0x3f]);
43 cw.write(alphabet[(x >> 6) & 0x3f]);
44 cw.write(alphabet[x & 0x3f]);
45
46 idx = 0;
47 }
48 }
49
50 if (idx == 1)
51 {
52 cw.write(alphabet[x >> 18]);
53 cw.write(alphabet[(x >> 12) & 0x3f]);
54 cw.write('=');
55 cw.write('=');
56 }
57
58 if (idx == 2)
59 {
60 cw.write(alphabet[x >> 18]);
61 cw.write(alphabet[(x >> 12) & 0x3f]);
62 cw.write(alphabet[(x >> 6) & 0x3f]);
63 cw.write('=');
64 }
65
66 return cw.toCharArray();
67 }
68
69 public static byte[] decode(char[] message) throws IOException
70 {
71 byte buff[] = new byte[4];
72 byte dest[] = new byte[message.length];
73
74 int bpos = 0;
75 int destpos = 0;
76
77 for (int i = 0; i < message.length; i++)
78 {
79 int c = message[i];
80
81 if ((c == '\n') || (c == '\r') || (c == ' ') || (c == '\t'))
82 continue;
83
84 if ((c >= 'A') && (c <= 'Z'))
85 {
86 buff[bpos++] = (byte) (c - 'A');
87 }
88 else if ((c >= 'a') && (c <= 'z'))
89 {
90 buff[bpos++] = (byte) ((c - 'a') + 26);
91 }
92 else if ((c >= '0') && (c <= '9'))
93 {
94 buff[bpos++] = (byte) ((c - '0') + 52);
95 }
96 else if (c == '+')
97 {
98 buff[bpos++] = 62;
99 }
100 else if (c == '/')
101 {
102 buff[bpos++] = 63;
103 }
104 else if (c == '=')
105 {
106 buff[bpos++] = 64;
107 }
108 else
109 {
110 throw new IOException("Illegal char in base64 code.");
111 }
112
113 if (bpos == 4)
114 {
115 bpos = 0;
116
117 if (buff[0] == 64)
118 break;
119
120 if (buff[1] == 64)
121 throw new IOException("Unexpected '=' in base64 code.");
122
123 if (buff[2] == 64)
124 {
125 int v = (((buff[0] & 0x3f) << 6) | ((buff[1] & 0x3f)));
126 dest[destpos++] = (byte) (v >> 4);
127 break;
128 }
129 else if (buff[3] == 64)
130 {
131 int v = (((buff[0] & 0x3f) << 12) | ((buff[1] & 0x3f) << 6) | ((buff[2] & 0x3f)));
132 dest[destpos++] = (byte) (v >> 10);
133 dest[destpos++] = (byte) (v >> 2);
134 break;
135 }
136 else
137 {
138 int v = (((buff[0] & 0x3f) << 18) | ((buff[1] & 0x3f) << 12) | ((buff[2] & 0x3f) << 6) | ((buff[3] & 0x3f)));
139 dest[destpos++] = (byte) (v >> 16);
140 dest[destpos++] = (byte) (v >> 8);
141 dest[destpos++] = (byte) (v);
142 }
143 }
144 }
145
146 byte[] res = new byte[destpos];
147 System.arraycopy(dest, 0, res, 0, destpos);
148
149 return res;
150 }
151 }