chiark / gitweb /
Fiddle with CSS+HTML in effort to get more consistent buttons
[disorder] / lib / hex.c
CommitLineData
460b9539 1/*
2 * This file is part of DisOrder
5aff007d 3 * Copyright (C) 2004, 2005, 2007, 2008 Richard Kettlewell
460b9539 4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
18 * USA
19 */
ed422be7 20/** @file lib/hex.c @brief Hexadecimal encoding and decoding */
460b9539 21
05b75f8d 22#include "common.h"
460b9539 23
24#include "hex.h"
25#include "mem.h"
26#include "log.h"
27
ed422be7
RK
28/** @brief Convert a byte sequence to hex
29 * @param ptr Pointer to first byte
30 * @param n Number of bytes
31 * @return Allocated string containing hexdump
32 */
460b9539 33char *hex(const uint8_t *ptr, size_t n) {
34 char *buf = xmalloc_noptr(n * 2 + 1), *p = buf;
35
36 while(n-- > 0)
37 p += sprintf(p, "%02x", (unsigned)*ptr++);
ef582771 38 *p = 0;
460b9539 39 return buf;
40}
41
ed422be7
RK
42/** @brief Convert a character to its value as a hex digit
43 * @param c Character code
44 * @return Value has hex digit or -1
45 *
46 * The 'q' stands for 'quiet' - this function does not report errors.
47 */
460b9539 48int unhexdigitq(int c) {
49 switch(c) {
50 case '0': return 0;
51 case '1': return 1;
52 case '2': return 2;
53 case '3': return 3;
54 case '4': return 4;
55 case '5': return 5;
56 case '6': return 6;
57 case '7': return 7;
58 case '8': return 8;
59 case '9': return 9;
60 case 'a': case 'A': return 10;
61 case 'b': case 'B': return 11;
62 case 'c': case 'C': return 12;
63 case 'd': case 'D': return 13;
64 case 'e': case 'E': return 14;
65 case 'f': case 'F': return 15;
66 default: return -1;
67 }
68}
69
ed422be7
RK
70/** @brief Convert a character to its value as a hex digit
71 * @param c Character code
72 * @return Value has hex digit or -1
73 *
74 * If the character is not a valid hex digit then an error is logged.
75 * See @ref unhexdigitq() if that is a problem.
76 */
460b9539 77int unhexdigit(int c) {
78 int d;
79
80 if((d = unhexdigitq(c)) < 0) error(0, "invalid hex digit");
81 return d;
82}
83
ed422be7
RK
84/** @brief Convert a hex string to bytes
85 * @param s Pointer to hex string
86 * @param np Where to store byte string length or NULL
87 * @return Allocated buffer, or 0
88 *
89 * @p s should point to a 0-terminated string containing an even number
90 * of hex digits. They are converted to bytes and returned via the return
91 * value and optionally the length via @p np.
92 *
93 * On any error a message is logged and a null pointer is returned.
94 */
460b9539 95uint8_t *unhex(const char *s, size_t *np) {
96 size_t l;
97 uint8_t *buf, *p;
98 int d1, d2;
99
100 if((l = strlen(s)) & 1) {
101 error(0, "hex string has odd length");
102 return 0;
103 }
104 p = buf = xmalloc_noptr(l / 2);
105 while(*s) {
106 if((d1 = unhexdigit(*s++)) < 0) return 0;
107 if((d2 = unhexdigit(*s++)) < 0) return 0;
108 *p++ = d1 * 16 + d2;
109 }
110 if(np)
111 *np = l / 2;
112 return buf;
113}
114
115/*
116Local Variables:
117c-basic-offset:2
118comment-column:40
119End:
120*/