unpack.c - dedup - deduplicating backup program
(HTM) git clone git://bitreich.org/dedup/ git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/dedup/
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unpack.c (2424B)
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1 /*
2 * ISC License
3 *
4 * (c) 2019 Roberto E. Vargas Caballero <k0ga@shike2.com>
5 *
6 * Permission to use, copy, modify, and/or distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <ctype.h>
20 #include <stdarg.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23
24 static int
25 lunpack(unsigned char *src, char *fmt, va_list va)
26 {
27 unsigned char *bp, *cp;
28 unsigned short *sp;
29 unsigned s;
30 unsigned long *lp, l;
31 unsigned long long *qp, q;
32 int n;
33
34 bp = src;
35 while (*fmt) {
36 switch (*fmt++) {
37 case '\'':
38 n = atoi(fmt);
39 while (isdigit(*fmt))
40 fmt++;
41 cp = va_arg(va, unsigned char *);
42 while (n--)
43 *cp++ = *bp++;
44 break;
45 case 'c':
46 cp = va_arg(va, unsigned char *);
47 *cp = *bp++;
48 break;
49 case 's':
50 sp = va_arg(va, unsigned short *);
51 s = (unsigned) *bp++;
52 s |= (unsigned) *bp++ << 8;
53 *sp = s;
54 break;
55 case 'l':
56 lp = va_arg(va, unsigned long *);
57 l = (unsigned long) *bp++;
58 l |= (unsigned long) *bp++ << 8;
59 l |= (unsigned long) *bp++ << 16;
60 l |= (unsigned long) *bp++ << 24;
61 *lp = l;
62 break;
63 case 'q':
64 qp = va_arg(va, unsigned long long *);
65 q = (unsigned long long) *bp++;
66 q |= (unsigned long long) *bp++ << 8;
67 q |= (unsigned long long) *bp++ << 16;
68 q |= (unsigned long long) *bp++ << 24;
69 q |= (unsigned long long) *bp++ << 32;
70 q |= (unsigned long long) *bp++ << 40;
71 q |= (unsigned long long) *bp++ << 48;
72 q |= (unsigned long long) *bp++ << 56;
73 *qp = q;
74 break;
75 default:
76 va_end(va);
77 return -1;
78 }
79 }
80
81 return bp - src;
82 }
83
84 int
85 unpack(unsigned char *src, char *fmt, ...)
86 {
87 int r;
88 int (*fn)(unsigned char *dst, char *fmt, va_list va);
89 va_list va;
90
91 va_start(va, fmt);
92 fn = lunpack;
93 r = (*fn)(src, fmt, va);
94 va_end(va);
95
96 return r;
97 }