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comparison src/com/trilead/ssh2/crypto/Base64.java @ 0:0ce5cc452d02

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initial version
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 10:41:19 -0700
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-1:000000000000 0:0ce5cc452d02
1
2 package com.trilead.ssh2.crypto;
3
4 import java.io.CharArrayWriter;
5 import java.io.IOException;
6
7 /**
8 * Basic Base64 Support.
9 *
10 * @author Christian Plattner, plattner@trilead.com
11 * @version $Id: Base64.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $
12 */
13 public class Base64 {
14 static final char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
15
16 public static char[] encode(byte[] content) {
17 CharArrayWriter cw = new CharArrayWriter((4 * content.length) / 3);
18 int idx = 0;
19 int x = 0;
20
21 for (int i = 0; i < content.length; i++) {
22 if (idx == 0)
23 x = (content[i] & 0xff) << 16;
24 else if (idx == 1)
25 x = x | ((content[i] & 0xff) << 8);
26 else
27 x = x | (content[i] & 0xff);
28
29 idx++;
30
31 if (idx == 3) {
32 cw.write(alphabet[x >> 18]);
33 cw.write(alphabet[(x >> 12) & 0x3f]);
34 cw.write(alphabet[(x >> 6) & 0x3f]);
35 cw.write(alphabet[x & 0x3f]);
36 idx = 0;
37 }
38 }
39
40 if (idx == 1) {
41 cw.write(alphabet[x >> 18]);
42 cw.write(alphabet[(x >> 12) & 0x3f]);
43 cw.write('=');
44 cw.write('=');
45 }
46
47 if (idx == 2) {
48 cw.write(alphabet[x >> 18]);
49 cw.write(alphabet[(x >> 12) & 0x3f]);
50 cw.write(alphabet[(x >> 6) & 0x3f]);
51 cw.write('=');
52 }
53
54 return cw.toCharArray();
55 }
56
57 public static byte[] decode(char[] message) throws IOException {
58 byte buff[] = new byte[4];
59 byte dest[] = new byte[message.length];
60 int bpos = 0;
61 int destpos = 0;
62
63 for (int i = 0; i < message.length; i++) {
64 int c = message[i];
65
66 if ((c == '\n') || (c == '\r') || (c == ' ') || (c == '\t'))
67 continue;
68
69 if ((c >= 'A') && (c <= 'Z')) {
70 buff[bpos++] = (byte)(c - 'A');
71 }
72 else if ((c >= 'a') && (c <= 'z')) {
73 buff[bpos++] = (byte)((c - 'a') + 26);
74 }
75 else if ((c >= '0') && (c <= '9')) {
76 buff[bpos++] = (byte)((c - '0') + 52);
77 }
78 else if (c == '+') {
79 buff[bpos++] = 62;
80 }
81 else if (c == '/') {
82 buff[bpos++] = 63;
83 }
84 else if (c == '=') {
85 buff[bpos++] = 64;
86 }
87 else {
88 throw new IOException("Illegal char in base64 code.");
89 }
90
91 if (bpos == 4) {
92 bpos = 0;
93
94 if (buff[0] == 64)
95 break;
96
97 if (buff[1] == 64)
98 throw new IOException("Unexpected '=' in base64 code.");
99
100 if (buff[2] == 64) {
101 int v = (((buff[0] & 0x3f) << 6) | ((buff[1] & 0x3f)));
102 dest[destpos++] = (byte)(v >> 4);
103 break;
104 }
105 else if (buff[3] == 64) {
106 int v = (((buff[0] & 0x3f) << 12) | ((buff[1] & 0x3f) << 6) | ((buff[2] & 0x3f)));
107 dest[destpos++] = (byte)(v >> 10);
108 dest[destpos++] = (byte)(v >> 2);
109 break;
110 }
111 else {
112 int v = (((buff[0] & 0x3f) << 18) | ((buff[1] & 0x3f) << 12) | ((buff[2] & 0x3f) << 6) | ((buff[3] & 0x3f)));
113 dest[destpos++] = (byte)(v >> 16);
114 dest[destpos++] = (byte)(v >> 8);
115 dest[destpos++] = (byte)(v);
116 }
117 }
118 }
119
120 byte[] res = new byte[destpos];
121 System.arraycopy(dest, 0, res, 0, destpos);
122 return res;
123 }
124 }