1 /*
2 * Copyright (C) 2010 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., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 #include <stdint.h>
27 #include <stdio.h>
28 #include <errno.h>
29 #include <assert.h>
30 #include <ipxe/string.h>
31 #include <ipxe/vsprintf.h>
32 #include <ipxe/base16.h>
33
34 /** @file
35 *
36 * Base16 encoding
37 *
38 */
39
40 /**
41 * Encode hexadecimal string (with optional byte separator character)
42 *
43 * @v separator Byte separator character, or 0 for no separator
44 * @v raw Raw data
45 * @v raw_len Length of raw data
46 * @v data Buffer
47 * @v len Length of buffer
48 * @ret len Encoded length
49 */
hex_encode(char separator,const void * raw,size_t raw_len,char * data,size_t len)50 size_t hex_encode ( char separator, const void *raw, size_t raw_len,
51 char *data, size_t len ) {
52 const uint8_t *bytes = raw;
53 const char delimiter[2] = { separator, '\0' };
54 size_t used = 0;
55 unsigned int i;
56
57 if ( len )
58 data[0] = 0; /* Ensure that a terminating NUL exists */
59 for ( i = 0 ; i < raw_len ; i++ ) {
60 used += ssnprintf ( ( data + used ), ( len - used ),
61 "%s%02x", ( used ? delimiter : "" ),
62 bytes[i] );
63 }
64 return used;
65 }
66
67 /**
68 * Decode hexadecimal string (with optional byte separator character)
69 *
70 * @v separator Byte separator character, or 0 for no separator
71 * @v encoded Encoded string
72 * @v data Buffer
73 * @v len Length of buffer
74 * @ret len Length of data, or negative error
75 */
hex_decode(char separator,const char * encoded,void * data,size_t len)76 int hex_decode ( char separator, const char *encoded, void *data, size_t len ) {
77 uint8_t *out = data;
78 unsigned int count = 0;
79 unsigned int sixteens;
80 unsigned int units;
81
82 while ( *encoded ) {
83
84 /* Check separator, if applicable */
85 if ( count && separator && ( ( *(encoded++) != separator ) ) )
86 return -EINVAL;
87
88 /* Extract digits. Note that either digit may be NUL,
89 * which would be interpreted as an invalid value by
90 * digit_value(); there is therefore no need for an
91 * explicit end-of-string check.
92 */
93 sixteens = digit_value ( *(encoded++) );
94 if ( sixteens >= 16 )
95 return -EINVAL;
96 units = digit_value ( *(encoded++) );
97 if ( units >= 16 )
98 return -EINVAL;
99
100 /* Store result */
101 if ( count < len )
102 out[count] = ( ( sixteens << 4 ) | units );
103 count++;
104
105 }
106 return count;
107 }
108