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fce810c2 RK |
1 | /* |
2 | * This file is part of DisOrder | |
3 | * Copyright (C) 2005, 2007 Richard Kettlewell | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but | |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 | |
18 | * USA | |
19 | */ | |
20 | /** @file lib/base64.c | |
21 | * @brief Support for MIME base64 | |
22 | */ | |
23 | ||
24 | #include <config.h> | |
25 | #include "types.h" | |
26 | ||
27 | #include <string.h> | |
28 | ||
29 | #include <stdio.h> | |
30 | ||
31 | #include "mem.h" | |
32 | #include "base64.h" | |
33 | #include "vector.h" | |
34 | ||
35 | static const char mime_base64_table[] = | |
36 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; | |
37 | ||
38 | /** @brief Convert MIME base64 | |
39 | * @param s base64 data | |
40 | * @return Decoded data | |
41 | */ | |
42 | char *mime_base64(const char *s, size_t *nsp) { | |
43 | struct dynstr d; | |
44 | const char *t; | |
45 | int b[4], n, c; | |
46 | ||
47 | dynstr_init(&d); | |
48 | n = 0; | |
49 | while((c = (unsigned char)*s++)) { | |
50 | if((t = strchr(mime_base64_table, c))) { | |
51 | b[n++] = t - mime_base64_table; | |
52 | if(n == 4) { | |
53 | dynstr_append(&d, (b[0] << 2) + (b[1] >> 4)); | |
54 | dynstr_append(&d, (b[1] << 4) + (b[2] >> 2)); | |
55 | dynstr_append(&d, (b[2] << 6) + b[3]); | |
56 | n = 0; | |
57 | } | |
58 | } else if(c == '=') { | |
59 | if(n >= 2) { | |
60 | dynstr_append(&d, (b[0] << 2) + (b[1] >> 4)); | |
61 | if(n == 3) | |
62 | dynstr_append(&d, (b[1] << 4) + (b[2] >> 2)); | |
63 | } | |
64 | break; | |
65 | } | |
66 | } | |
67 | if(nsp) | |
68 | *nsp = d.nvec; | |
69 | dynstr_terminate(&d); | |
70 | return d.vec; | |
71 | } | |
72 | ||
73 | /** @brief Convert a binary string to base64 | |
74 | * @param s Bytes to convert | |
75 | * @param ns Number of bytes to convert | |
76 | * @return Encoded data | |
77 | * | |
78 | * This function does not attempt to split up lines. | |
79 | */ | |
80 | char *mime_to_base64(const uint8_t *s, size_t ns) { | |
81 | struct dynstr d[1]; | |
82 | ||
83 | dynstr_init(d); | |
84 | while(ns >= 3) { | |
85 | /* Input bytes with output bits: AAAAAABB BBBBCCCC CCDDDDDD */ | |
86 | /* Output bytes with input bits: 000000 001111 111122 222222 */ | |
87 | dynstr_append(d, mime_base64_table[s[0] >> 2]); | |
88 | dynstr_append(d, mime_base64_table[((s[0] & 3) << 4) | |
89 | + (s[1] >> 4)]); | |
90 | dynstr_append(d, mime_base64_table[((s[1] & 15) << 2) | |
91 | + (s[2] >> 6)]); | |
92 | dynstr_append(d, mime_base64_table[s[2] & 63]); | |
93 | ns -= 3; | |
94 | s += 3; | |
95 | } | |
96 | if(ns > 0) { | |
97 | dynstr_append(d, mime_base64_table[s[0] >> 2]); | |
98 | switch(ns) { | |
99 | case 1: | |
100 | dynstr_append(d, mime_base64_table[(s[0] & 3) << 4]); | |
101 | dynstr_append(d, '='); | |
102 | dynstr_append(d, '='); | |
103 | break; | |
104 | case 2: | |
105 | dynstr_append(d, mime_base64_table[((s[0] & 3) << 4) | |
106 | + (s[1] >> 4)]); | |
107 | dynstr_append(d, mime_base64_table[(s[1] & 15) << 2]); | |
108 | dynstr_append(d, '='); | |
109 | break; | |
110 | } | |
111 | } | |
112 | dynstr_terminate(d); | |
113 | return d->vec; | |
114 | } | |
115 | ||
116 | /* | |
117 | Local Variables: | |
118 | c-basic-offset:2 | |
119 | comment-column:40 | |
120 | fill-column:79 | |
121 | End: | |
122 | */ |