hex.c revision 178825 
1/*
2 * Copyright (c) 2004-2005 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifdef HAVE_CONFIG_H
35#include <config.h>
36RCSID("$Id: hex.c 16504 2006-01-09 17:09:29Z lha $");
37#endif
38#include "roken.h"
39#include <ctype.h>
40#include "hex.h"
41
42const static char hexchar[] = "0123456789ABCDEF";
43
44static int
45pos(char c)
46{
47    const char *p;
48    c = toupper((unsigned char)c);
49    for (p = hexchar; *p; p++)
50	if (*p == c)
51	    return p - hexchar;
52    return -1;
53}
54
55ssize_t ROKEN_LIB_FUNCTION
56hex_encode(const void *data, size_t size, char **str)
57{
58    const unsigned char *q = data;
59    size_t i;
60    char *p;
61
62    /* check for overflow */
63    if (size * 2 < size)
64	return -1;
65
66    p = malloc(size * 2 + 1);
67    if (p == NULL)
68	return -1;
69
70    for (i = 0; i < size; i++) {
71	p[i * 2] = hexchar[(*q >> 4) & 0xf];
72	p[i * 2 + 1] = hexchar[*q & 0xf];
73	q++;
74    }
75    p[i * 2] = '\0';
76    *str = p;
77
78    return i * 2;
79}
80
81ssize_t ROKEN_LIB_FUNCTION
82hex_decode(const char *str, void *data, size_t len)
83{
84    size_t l;
85    unsigned char *p = data;
86    size_t i;
87
88    l = strlen(str);
89
90    /* check for overflow, same as (l+1)/2 but overflow safe */
91    if ((l/2) + (l&1) > len)
92	return -1;
93
94    i = 0;
95    if (l & 1) {
96	p[0] = pos(str[0]);
97	str++;
98	p++;
99    }
100    for (i = 0; i < l / 2; i++)
101	p[i] = pos(str[i * 2]) << 4 | pos(str[(i * 2) + 1]);
102    return i + (l & 1);
103}
104