chiark / gitweb /
make sure disorder-normalize gets the right config file
[disorder] / lib / base64.c
CommitLineData
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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
35static const char mime_base64_table[] =
36 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
37
38/** @brief Convert MIME base64
39 * @param s base64 data
158d0961 40 * @param nsp Where to store length of converted data
fce810c2 41 * @return Decoded data
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42 *
43 * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC
44 * 2045 s6.8</a>.
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45 */
46char *mime_base64(const char *s, size_t *nsp) {
47 struct dynstr d;
48 const char *t;
49 int b[4], n, c;
50
51 dynstr_init(&d);
52 n = 0;
53 while((c = (unsigned char)*s++)) {
54 if((t = strchr(mime_base64_table, c))) {
55 b[n++] = t - mime_base64_table;
56 if(n == 4) {
57 dynstr_append(&d, (b[0] << 2) + (b[1] >> 4));
58 dynstr_append(&d, (b[1] << 4) + (b[2] >> 2));
59 dynstr_append(&d, (b[2] << 6) + b[3]);
60 n = 0;
61 }
62 } else if(c == '=') {
63 if(n >= 2) {
64 dynstr_append(&d, (b[0] << 2) + (b[1] >> 4));
65 if(n == 3)
66 dynstr_append(&d, (b[1] << 4) + (b[2] >> 2));
67 }
68 break;
69 }
70 }
71 if(nsp)
72 *nsp = d.nvec;
73 dynstr_terminate(&d);
74 return d.vec;
75}
76
77/** @brief Convert a binary string to base64
78 * @param s Bytes to convert
79 * @param ns Number of bytes to convert
80 * @return Encoded data
81 *
82 * This function does not attempt to split up lines.
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83 *
84 * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC
85 * 2045 s6.8</a>.
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86 */
87char *mime_to_base64(const uint8_t *s, size_t ns) {
88 struct dynstr d[1];
89
90 dynstr_init(d);
91 while(ns >= 3) {
92 /* Input bytes with output bits: AAAAAABB BBBBCCCC CCDDDDDD */
93 /* Output bytes with input bits: 000000 001111 111122 222222 */
94 dynstr_append(d, mime_base64_table[s[0] >> 2]);
95 dynstr_append(d, mime_base64_table[((s[0] & 3) << 4)
96 + (s[1] >> 4)]);
97 dynstr_append(d, mime_base64_table[((s[1] & 15) << 2)
98 + (s[2] >> 6)]);
99 dynstr_append(d, mime_base64_table[s[2] & 63]);
100 ns -= 3;
101 s += 3;
102 }
103 if(ns > 0) {
104 dynstr_append(d, mime_base64_table[s[0] >> 2]);
105 switch(ns) {
106 case 1:
107 dynstr_append(d, mime_base64_table[(s[0] & 3) << 4]);
108 dynstr_append(d, '=');
109 dynstr_append(d, '=');
110 break;
111 case 2:
112 dynstr_append(d, mime_base64_table[((s[0] & 3) << 4)
113 + (s[1] >> 4)]);
114 dynstr_append(d, mime_base64_table[(s[1] & 15) << 2]);
115 dynstr_append(d, '=');
116 break;
117 }
118 }
119 dynstr_terminate(d);
120 return d->vec;
121}
122
123/*
124Local Variables:
125c-basic-offset:2
126comment-column:40
127fill-column:79
128End:
129*/