1/*
2 * Copyright (c) 2004-2005 Kungliga Tekniska Högskolan
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
35#include <config.h>
36#include "roken.h"
37#include <ctype.h>
38#include "hex.h"
39
40static const char hexchar[16] = "0123456789ABCDEF";
41
42static int
43pos(char c)
44{
45    const char *p;
46    c = toupper((unsigned char)c);
47    for (p = hexchar; *p; p++)
48	if (*p == c)
49	    return (int)(p - hexchar);
50    return -1;
51}
52
53ROKEN_LIB_FUNCTION ssize_t ROKEN_LIB_CALL
54hex_encode(const void *data, size_t size, char **str)
55{
56    const unsigned char *q = data;
57    size_t i;
58    char *p;
59
60    /* check for overflow */
61    if (size * 2 < size) {
62        *str = NULL;
63	return -1;
64    }
65
66    p = malloc(size * 2 + 1);
67    if (p == NULL) {
68        *str = NULL;
69	return -1;
70    }
71
72    for (i = 0; i < size; i++) {
73	p[i * 2] = hexchar[(*q >> 4) & 0xf];
74	p[i * 2 + 1] = hexchar[*q & 0xf];
75	q++;
76    }
77    p[i * 2] = '\0';
78    *str = p;
79
80    return i * 2;
81}
82
83ROKEN_LIB_FUNCTION ssize_t ROKEN_LIB_CALL
84hex_decode(const char *str, void *data, size_t len)
85{
86    size_t l;
87    unsigned char *p = data;
88    size_t i;
89
90    l = strlen(str);
91
92    /* check for overflow, same as (l+1)/2 but overflow safe */
93    if ((l/2) + (l&1) > len)
94	return -1;
95
96    if (l & 1) {
97	p[0] = pos(str[0]);
98	str++;
99	p++;
100    }
101    for (i = 0; i < l / 2; i++)
102	p[i] = pos(str[i * 2]) << 4 | pos(str[(i * 2) + 1]);
103    return i + (l & 1);
104}
105