2 * This file is part of DisOrder
3 * Copyright (C) 2005, 2007 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
35 static const char mime_base64_table
[] =
36 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
38 /** @brief Convert MIME base64
39 * @param s base64 data
40 * @param nsp Where to store length of converted data
41 * @param table Table of characters to use
42 * @return Decoded data
44 * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC
47 char *mime_base64(const char *s
, size_t *nsp
) {
48 return generic_base64(s
, nsp
, mime_base64_table
);
51 /** @brief Convert base64
52 * @param s base64 data
53 * @param nsp Where to store length of converted data
54 * @return Decoded data
56 * @p table should consist of 65 characters. The first 64 will be used to
57 * represents the 64 digits and the 65th will be used as padding at the end
58 * (i.e. the role of '=' in RFC2045 base64).
60 char *generic_base64(const char *s
, size_t *nsp
, const char *table
) {
67 while((c
= (unsigned char)*s
++)) {
70 dynstr_append(&d
, (b
[0] << 2) + (b
[1] >> 4));
72 dynstr_append(&d
, (b
[1] << 4) + (b
[2] >> 2));
75 } else if((t
= strchr(table
, c
))) {
78 dynstr_append(&d
, (b
[0] << 2) + (b
[1] >> 4));
79 dynstr_append(&d
, (b
[1] << 4) + (b
[2] >> 2));
80 dynstr_append(&d
, (b
[2] << 6) + b
[3]);
91 /** @brief Convert a binary string to MIME base64
92 * @param s Bytes to convert
93 * @param ns Number of bytes to convert
94 * @return Encoded data
96 * This function does not attempt to split up lines.
98 * See <a href="http://tools.ietf.org/html/rfc2045#section-6.8">RFC
101 char *mime_to_base64(const uint8_t *s
, size_t ns
) {
102 return generic_to_base64(s
, ns
, mime_base64_table
);
105 /** @brief Convert a binary string to base64
106 * @param s Bytes to convert
107 * @param ns Number of bytes to convert
108 * @param table Table of characters to use
109 * @return Encoded data
111 * This function does not attempt to split up lines.
113 * @p table should consist of 65 characters. The first 64 will be used to
114 * represents the 64 digits and the 65th will be used as padding at the end
115 * (i.e. the role of '=' in RFC2045 base64).
117 char *generic_to_base64(const uint8_t *s
, size_t ns
, const char *table
) {
122 /* Input bytes with output bits: AAAAAABB BBBBCCCC CCDDDDDD */
123 /* Output bytes with input bits: 000000 001111 111122 222222 */
124 dynstr_append(d
, table
[s
[0] >> 2]);
125 dynstr_append(d
, table
[((s
[0] & 3) << 4)
127 dynstr_append(d
, table
[((s
[1] & 15) << 2)
129 dynstr_append(d
, table
[s
[2] & 63]);
134 dynstr_append(d
, table
[s
[0] >> 2]);
137 dynstr_append(d
, table
[(s
[0] & 3) << 4]);
138 dynstr_append(d
, table
[64]);
139 dynstr_append(d
, table
[64]);
142 dynstr_append(d
, table
[((s
[0] & 3) << 4)
144 dynstr_append(d
, table
[(s
[1] & 15) << 2]);
145 dynstr_append(d
, table
[64]);