1 /*
2 * Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <stdint.h>
22 #include <string.h>
23 #include <assert.h>
24 #include <gpxe/base64.h>
25
26 /** @file
27 *
28 * Base64 encoding
29 *
30 */
31
32 static const char base64[64] =
33 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
34
35 /**
36 * Base64-encode a string
37 *
38 * @v raw Raw string
39 * @v encoded Buffer for encoded string
40 *
41 * The buffer must be the correct length for the encoded string. Use
42 * something like
43 *
44 * char buf[ base64_encoded_len ( strlen ( raw ) ) + 1 ];
45 *
46 * (the +1 is for the terminating NUL) to provide a buffer of the
47 * correct size.
48 */
base64_encode(const char * raw,char * encoded)49 void base64_encode ( const char *raw, char *encoded ) {
50 const uint8_t *raw_bytes = ( ( const uint8_t * ) raw );
51 uint8_t *encoded_bytes = ( ( uint8_t * ) encoded );
52 size_t raw_bit_len = ( 8 * strlen ( raw ) );
53 unsigned int bit;
54 unsigned int tmp;
55
56 for ( bit = 0 ; bit < raw_bit_len ; bit += 6 ) {
57 tmp = ( ( raw_bytes[ bit / 8 ] << ( bit % 8 ) ) |
58 ( raw_bytes[ bit / 8 + 1 ] >> ( 8 - ( bit % 8 ) ) ) );
59 tmp = ( ( tmp >> 2 ) & 0x3f );
60 *(encoded_bytes++) = base64[tmp];
61 }
62 for ( ; ( bit % 8 ) != 0 ; bit += 6 )
63 *(encoded_bytes++) = '=';
64 *(encoded_bytes++) = '\0';
65
66 DBG ( "Base64-encoded \"%s\" as \"%s\"\n", raw, encoded );
67 assert ( strlen ( encoded ) == base64_encoded_len ( strlen ( raw ) ) );
68 }
69