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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 | |
78d8e29d RK |
41 | * |
42 | * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC | |
43 | * 2045 s6.8</a>. | |
fce810c2 RK |
44 | */ |
45 | char *mime_base64(const char *s, size_t *nsp) { | |
46 | struct dynstr d; | |
47 | const char *t; | |
48 | int b[4], n, c; | |
49 | ||
50 | dynstr_init(&d); | |
51 | n = 0; | |
52 | while((c = (unsigned char)*s++)) { | |
53 | if((t = strchr(mime_base64_table, c))) { | |
54 | b[n++] = t - mime_base64_table; | |
55 | if(n == 4) { | |
56 | dynstr_append(&d, (b[0] << 2) + (b[1] >> 4)); | |
57 | dynstr_append(&d, (b[1] << 4) + (b[2] >> 2)); | |
58 | dynstr_append(&d, (b[2] << 6) + b[3]); | |
59 | n = 0; | |
60 | } | |
61 | } else if(c == '=') { | |
62 | if(n >= 2) { | |
63 | dynstr_append(&d, (b[0] << 2) + (b[1] >> 4)); | |
64 | if(n == 3) | |
65 | dynstr_append(&d, (b[1] << 4) + (b[2] >> 2)); | |
66 | } | |
67 | break; | |
68 | } | |
69 | } | |
70 | if(nsp) | |
71 | *nsp = d.nvec; | |
72 | dynstr_terminate(&d); | |
73 | return d.vec; | |
74 | } | |
75 | ||
76 | /** @brief Convert a binary string to base64 | |
77 | * @param s Bytes to convert | |
78 | * @param ns Number of bytes to convert | |
79 | * @return Encoded data | |
80 | * | |
81 | * This function does not attempt to split up lines. | |
78d8e29d RK |
82 | * |
83 | * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC | |
84 | * 2045 s6.8</a>. | |
fce810c2 RK |
85 | */ |
86 | char *mime_to_base64(const uint8_t *s, size_t ns) { | |
87 | struct dynstr d[1]; | |
88 | ||
89 | dynstr_init(d); | |
90 | while(ns >= 3) { | |
91 | /* Input bytes with output bits: AAAAAABB BBBBCCCC CCDDDDDD */ | |
92 | /* Output bytes with input bits: 000000 001111 111122 222222 */ | |
93 | dynstr_append(d, mime_base64_table[s[0] >> 2]); | |
94 | dynstr_append(d, mime_base64_table[((s[0] & 3) << 4) | |
95 | + (s[1] >> 4)]); | |
96 | dynstr_append(d, mime_base64_table[((s[1] & 15) << 2) | |
97 | + (s[2] >> 6)]); | |
98 | dynstr_append(d, mime_base64_table[s[2] & 63]); | |
99 | ns -= 3; | |
100 | s += 3; | |
101 | } | |
102 | if(ns > 0) { | |
103 | dynstr_append(d, mime_base64_table[s[0] >> 2]); | |
104 | switch(ns) { | |
105 | case 1: | |
106 | dynstr_append(d, mime_base64_table[(s[0] & 3) << 4]); | |
107 | dynstr_append(d, '='); | |
108 | dynstr_append(d, '='); | |
109 | break; | |
110 | case 2: | |
111 | dynstr_append(d, mime_base64_table[((s[0] & 3) << 4) | |
112 | + (s[1] >> 4)]); | |
113 | dynstr_append(d, mime_base64_table[(s[1] & 15) << 2]); | |
114 | dynstr_append(d, '='); | |
115 | break; | |
116 | } | |
117 | } | |
118 | dynstr_terminate(d); | |
119 | return d->vec; | |
120 | } | |
121 | ||
122 | /* | |
123 | Local Variables: | |
124 | c-basic-offset:2 | |
125 | comment-column:40 | |
126 | fill-column:79 | |
127 | End: | |
128 | */ |