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fce810c2 RK |
1 | /* |
2 | * This file is part of DisOrder | |
5aff007d | 3 | * Copyright (C) 2005, 2007, 2008 Richard Kettlewell |
fce810c2 | 4 | * |
e7eb3a27 | 5 | * This program is free software: you can redistribute it and/or modify |
fce810c2 | 6 | * it under the terms of the GNU General Public License as published by |
e7eb3a27 | 7 | * the Free Software Foundation, either version 3 of the License, or |
fce810c2 | 8 | * (at your option) any later version. |
e7eb3a27 RK |
9 | * |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
fce810c2 | 15 | * You should have received a copy of the GNU General Public License |
e7eb3a27 | 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
fce810c2 RK |
17 | */ |
18 | /** @file lib/base64.c | |
19 | * @brief Support for MIME base64 | |
20 | */ | |
21 | ||
05b75f8d | 22 | #include "common.h" |
fce810c2 RK |
23 | |
24 | #include "mem.h" | |
25 | #include "base64.h" | |
26 | #include "vector.h" | |
27 | ||
28 | static const char mime_base64_table[] = | |
86e3aea7 | 29 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; |
fce810c2 RK |
30 | |
31 | /** @brief Convert MIME base64 | |
32 | * @param s base64 data | |
158d0961 | 33 | * @param nsp Where to store length of converted data |
fce810c2 | 34 | * @return Decoded data |
78d8e29d RK |
35 | * |
36 | * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC | |
37 | * 2045 s6.8</a>. | |
fce810c2 RK |
38 | */ |
39 | char *mime_base64(const char *s, size_t *nsp) { | |
86e3aea7 | 40 | return generic_base64(s, nsp, mime_base64_table); |
41 | } | |
42 | ||
43 | /** @brief Convert base64 | |
44 | * @param s base64 data | |
45 | * @param nsp Where to store length of converted data | |
0590cedc | 46 | * @param table Table of characters to use |
86e3aea7 | 47 | * @return Decoded data |
48 | * | |
49 | * @p table should consist of 65 characters. The first 64 will be used to | |
50 | * represents the 64 digits and the 65th will be used as padding at the end | |
51 | * (i.e. the role of '=' in RFC2045 base64). | |
52 | */ | |
53 | char *generic_base64(const char *s, size_t *nsp, const char *table) { | |
fce810c2 RK |
54 | struct dynstr d; |
55 | const char *t; | |
56 | int b[4], n, c; | |
57 | ||
58 | dynstr_init(&d); | |
59 | n = 0; | |
60 | while((c = (unsigned char)*s++)) { | |
4d06b900 | 61 | if(c == table[64]) { |
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 | } else if((t = strchr(table, c))) { | |
86e3aea7 | 69 | b[n++] = t - table; |
fce810c2 RK |
70 | if(n == 4) { |
71 | dynstr_append(&d, (b[0] << 2) + (b[1] >> 4)); | |
72 | dynstr_append(&d, (b[1] << 4) + (b[2] >> 2)); | |
73 | dynstr_append(&d, (b[2] << 6) + b[3]); | |
74 | n = 0; | |
75 | } | |
fce810c2 RK |
76 | } |
77 | } | |
78 | if(nsp) | |
79 | *nsp = d.nvec; | |
80 | dynstr_terminate(&d); | |
81 | return d.vec; | |
82 | } | |
83 | ||
86e3aea7 | 84 | /** @brief Convert a binary string to MIME base64 |
fce810c2 RK |
85 | * @param s Bytes to convert |
86 | * @param ns Number of bytes to convert | |
87 | * @return Encoded data | |
88 | * | |
89 | * This function does not attempt to split up lines. | |
78d8e29d RK |
90 | * |
91 | * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC | |
92 | * 2045 s6.8</a>. | |
fce810c2 RK |
93 | */ |
94 | char *mime_to_base64(const uint8_t *s, size_t ns) { | |
86e3aea7 | 95 | return generic_to_base64(s, ns, mime_base64_table); |
96 | } | |
97 | ||
98 | /** @brief Convert a binary string to base64 | |
99 | * @param s Bytes to convert | |
100 | * @param ns Number of bytes to convert | |
101 | * @param table Table of characters to use | |
102 | * @return Encoded data | |
103 | * | |
104 | * This function does not attempt to split up lines. | |
105 | * | |
106 | * @p table should consist of 65 characters. The first 64 will be used to | |
107 | * represents the 64 digits and the 65th will be used as padding at the end | |
108 | * (i.e. the role of '=' in RFC2045 base64). | |
109 | */ | |
110 | char *generic_to_base64(const uint8_t *s, size_t ns, const char *table) { | |
fce810c2 RK |
111 | struct dynstr d[1]; |
112 | ||
113 | dynstr_init(d); | |
114 | while(ns >= 3) { | |
115 | /* Input bytes with output bits: AAAAAABB BBBBCCCC CCDDDDDD */ | |
116 | /* Output bytes with input bits: 000000 001111 111122 222222 */ | |
86e3aea7 | 117 | dynstr_append(d, table[s[0] >> 2]); |
118 | dynstr_append(d, table[((s[0] & 3) << 4) | |
fce810c2 | 119 | + (s[1] >> 4)]); |
86e3aea7 | 120 | dynstr_append(d, table[((s[1] & 15) << 2) |
fce810c2 | 121 | + (s[2] >> 6)]); |
86e3aea7 | 122 | dynstr_append(d, table[s[2] & 63]); |
fce810c2 RK |
123 | ns -= 3; |
124 | s += 3; | |
125 | } | |
126 | if(ns > 0) { | |
86e3aea7 | 127 | dynstr_append(d, table[s[0] >> 2]); |
fce810c2 RK |
128 | switch(ns) { |
129 | case 1: | |
86e3aea7 | 130 | dynstr_append(d, table[(s[0] & 3) << 4]); |
131 | dynstr_append(d, table[64]); | |
132 | dynstr_append(d, table[64]); | |
fce810c2 RK |
133 | break; |
134 | case 2: | |
86e3aea7 | 135 | dynstr_append(d, table[((s[0] & 3) << 4) |
fce810c2 | 136 | + (s[1] >> 4)]); |
86e3aea7 | 137 | dynstr_append(d, table[(s[1] & 15) << 2]); |
138 | dynstr_append(d, table[64]); | |
fce810c2 RK |
139 | break; |
140 | } | |
141 | } | |
142 | dynstr_terminate(d); | |
143 | return d->vec; | |
144 | } | |
145 | ||
146 | /* | |
147 | Local Variables: | |
148 | c-basic-offset:2 | |
149 | comment-column:40 | |
150 | fill-column:79 | |
151 | End: | |
152 | */ |