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460b9539 | 1 | /* |
2 | * This file is part of DisOrder | |
3c95f40e | 3 | * Copyright (C) 2004, 2005, 2007-9, 2013 Richard Kettlewell |
460b9539 | 4 | * |
e7eb3a27 | 5 | * This program is free software: you can redistribute it and/or modify |
460b9539 | 6 | * it under the terms of the GNU General Public License as published by |
e7eb3a27 | 7 | * the Free Software Foundation, either version 3 of the License, or |
460b9539 | 8 | * (at your option) any later version. |
e7eb3a27 RK |
9 | * |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
460b9539 | 15 | * You should have received a copy of the GNU General Public License |
e7eb3a27 | 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
460b9539 | 17 | */ |
ed422be7 | 18 | /** @file lib/hex.c @brief Hexadecimal encoding and decoding */ |
460b9539 | 19 | |
05b75f8d | 20 | #include "common.h" |
460b9539 | 21 | |
22 | #include "hex.h" | |
23 | #include "mem.h" | |
24 | #include "log.h" | |
3c95f40e | 25 | #include "printf.h" |
460b9539 | 26 | |
ed422be7 RK |
27 | /** @brief Convert a byte sequence to hex |
28 | * @param ptr Pointer to first byte | |
29 | * @param n Number of bytes | |
30 | * @return Allocated string containing hexdump | |
31 | */ | |
460b9539 | 32 | char *hex(const uint8_t *ptr, size_t n) { |
33 | char *buf = xmalloc_noptr(n * 2 + 1), *p = buf; | |
34 | ||
35 | while(n-- > 0) | |
3c95f40e | 36 | p += byte_snprintf(p, 3, "%02x", (unsigned)*ptr++); |
ef582771 | 37 | *p = 0; |
460b9539 | 38 | return buf; |
39 | } | |
40 | ||
ed422be7 RK |
41 | /** @brief Convert a character to its value as a hex digit |
42 | * @param c Character code | |
43 | * @return Value has hex digit or -1 | |
44 | * | |
45 | * The 'q' stands for 'quiet' - this function does not report errors. | |
46 | */ | |
460b9539 | 47 | int unhexdigitq(int c) { |
48 | switch(c) { | |
49 | case '0': return 0; | |
50 | case '1': return 1; | |
51 | case '2': return 2; | |
52 | case '3': return 3; | |
53 | case '4': return 4; | |
54 | case '5': return 5; | |
55 | case '6': return 6; | |
56 | case '7': return 7; | |
57 | case '8': return 8; | |
58 | case '9': return 9; | |
59 | case 'a': case 'A': return 10; | |
60 | case 'b': case 'B': return 11; | |
61 | case 'c': case 'C': return 12; | |
62 | case 'd': case 'D': return 13; | |
63 | case 'e': case 'E': return 14; | |
64 | case 'f': case 'F': return 15; | |
65 | default: return -1; | |
66 | } | |
67 | } | |
68 | ||
ed422be7 RK |
69 | /** @brief Convert a character to its value as a hex digit |
70 | * @param c Character code | |
71 | * @return Value has hex digit or -1 | |
72 | * | |
73 | * If the character is not a valid hex digit then an error is logged. | |
74 | * See @ref unhexdigitq() if that is a problem. | |
75 | */ | |
460b9539 | 76 | int unhexdigit(int c) { |
77 | int d; | |
78 | ||
2e9ba080 RK |
79 | if((d = unhexdigitq(c)) < 0) |
80 | disorder_error(0, "invalid hex digit"); | |
460b9539 | 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 | 95 | uint8_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) { | |
2e9ba080 | 101 | disorder_error(0, "hex string has odd length"); |
460b9539 | 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 | /* | |
116 | Local Variables: | |
117 | c-basic-offset:2 | |
118 | comment-column:40 | |
119 | End: | |
120 | */ |