1/*	$NetBSD: hex.c,v 1.1.1.1 2011/04/13 18:15:41 elric Exp $	*/
2
3/*
4 * Copyright (c) 2004-2005 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36
37#include <config.h>
38#include <krb5/roken.h>
39#include <ctype.h>
40#include <krb5/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
55ROKEN_LIB_FUNCTION ssize_t ROKEN_LIB_CALL
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        *str = NULL;
65	return -1;
66    }
67
68    p = malloc(size * 2 + 1);
69    if (p == NULL) {
70        *str = NULL;
71	return -1;
72    }
73
74    for (i = 0; i < size; i++) {
75	p[i * 2] = hexchar[(*q >> 4) & 0xf];
76	p[i * 2 + 1] = hexchar[*q & 0xf];
77	q++;
78    }
79    p[i * 2] = '\0';
80    *str = p;
81
82    return i * 2;
83}
84
85ROKEN_LIB_FUNCTION ssize_t ROKEN_LIB_CALL
86hex_decode(const char *str, void *data, size_t len)
87{
88    size_t l;
89    unsigned char *p = data;
90    size_t i;
91
92    l = strlen(str);
93
94    /* check for overflow, same as (l+1)/2 but overflow safe */
95    if ((l/2) + (l&1) > len)
96	return -1;
97
98    i = 0;
99    if (l & 1) {
100	p[0] = pos(str[0]);
101	str++;
102	p++;
103    }
104    for (i = 0; i < l / 2; i++)
105	p[i] = pos(str[i * 2]) << 4 | pos(str[(i * 2) + 1]);
106    return i + (l & 1);
107}
108