xref: /freebsd/crypto/heimdal/lib/roken/hex.c (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
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 
40 static const char hexchar[16] = "0123456789ABCDEF";
41 
42 static int
43 pos(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 p - hexchar;
50     return -1;
51 }
52 
53 ROKEN_LIB_FUNCTION ssize_t ROKEN_LIB_CALL
54 hex_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 
83 ROKEN_LIB_FUNCTION ssize_t ROKEN_LIB_CALL
84 hex_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