2 * This file is part of DisOrder
3 * Copyright (C) 2005, 2007, 2008 Richard Kettlewell
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.
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.
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
20 /** @file lib/base64.c
21 * @brief Support for MIME base64
30 static const char mime_base64_table
[] =
31 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
33 /** @brief Convert MIME base64
34 * @param s base64 data
35 * @param nsp Where to store length of converted data
36 * @return Decoded data
38 * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC
41 char *mime_base64(const char *s
, size_t *nsp
) {
42 return generic_base64(s
, nsp
, mime_base64_table
);
45 /** @brief Convert base64
46 * @param s base64 data
47 * @param nsp Where to store length of converted data
48 * @param table Table of characters to use
49 * @return Decoded data
51 * @p table should consist of 65 characters. The first 64 will be used to
52 * represents the 64 digits and the 65th will be used as padding at the end
53 * (i.e. the role of '=' in RFC2045 base64).
55 char *generic_base64(const char *s
, size_t *nsp
, const char *table
) {
62 while((c
= (unsigned char)*s
++)) {
65 dynstr_append(&d
, (b
[0] << 2) + (b
[1] >> 4));
67 dynstr_append(&d
, (b
[1] << 4) + (b
[2] >> 2));
70 } else if((t
= strchr(table
, c
))) {
73 dynstr_append(&d
, (b
[0] << 2) + (b
[1] >> 4));
74 dynstr_append(&d
, (b
[1] << 4) + (b
[2] >> 2));
75 dynstr_append(&d
, (b
[2] << 6) + b
[3]);
86 /** @brief Convert a binary string to MIME base64
87 * @param s Bytes to convert
88 * @param ns Number of bytes to convert
89 * @return Encoded data
91 * This function does not attempt to split up lines.
93 * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC
96 char *mime_to_base64(const uint8_t *s
, size_t ns
) {
97 return generic_to_base64(s
, ns
, mime_base64_table
);
100 /** @brief Convert a binary string to base64
101 * @param s Bytes to convert
102 * @param ns Number of bytes to convert
103 * @param table Table of characters to use
104 * @return Encoded data
106 * This function does not attempt to split up lines.
108 * @p table should consist of 65 characters. The first 64 will be used to
109 * represents the 64 digits and the 65th will be used as padding at the end
110 * (i.e. the role of '=' in RFC2045 base64).
112 char *generic_to_base64(const uint8_t *s
, size_t ns
, const char *table
) {
117 /* Input bytes with output bits: AAAAAABB BBBBCCCC CCDDDDDD */
118 /* Output bytes with input bits: 000000 001111 111122 222222 */
119 dynstr_append(d
, table
[s
[0] >> 2]);
120 dynstr_append(d
, table
[((s
[0] & 3) << 4)
122 dynstr_append(d
, table
[((s
[1] & 15) << 2)
124 dynstr_append(d
, table
[s
[2] & 63]);
129 dynstr_append(d
, table
[s
[0] >> 2]);
132 dynstr_append(d
, table
[(s
[0] & 3) << 4]);
133 dynstr_append(d
, table
[64]);
134 dynstr_append(d
, table
[64]);
137 dynstr_append(d
, table
[((s
[0] & 3) << 4)
139 dynstr_append(d
, table
[(s
[1] & 15) << 2]);
140 dynstr_append(d
, table
[64]);