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unpack.c - scc - simple c99 compiler
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unpack.c (2889B)
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1 #include <ctype.h>
2 #include <stdarg.h>
3 #include <stdio.h>
4 #include <stdlib.h>
5
6 #include <scc/mach.h>
7 #include "libmach.h"
8
9 static int
10 lunpack(unsigned char *src, char *fmt, va_list va)
11 {
12 unsigned char *bp, *cp;
13 unsigned short *sp;
14 unsigned s;
15 unsigned long *lp, l;
16 unsigned long long *qp, q;
17 int n;
18
19 bp = src;
20 while (*fmt) {
21 switch (*fmt++) {
22 case '\'':
23 n = atoi(fmt);
24 while (isdigit(*fmt))
25 fmt++;
26 cp = va_arg(va, unsigned char *);
27 while (n--)
28 *cp++ = *bp++;
29 break;
30 case 'c':
31 cp = va_arg(va, unsigned char *);
32 *cp = *bp++;
33 break;
34 case 's':
35 sp = va_arg(va, unsigned short *);
36 s = (unsigned) *bp++;
37 s |= (unsigned) *bp++ << 8;
38 *sp = s;
39 break;
40 case 'l':
41 lp = va_arg(va, unsigned long *);
42 l = (unsigned long) *bp++;
43 l |= (unsigned long) *bp++ << 8;
44 l |= (unsigned long) *bp++ << 16;
45 l |= (unsigned long) *bp++ << 24;
46 *lp = l;
47 break;
48 case 'q':
49 qp = va_arg(va, unsigned long long *);
50 q = (unsigned long long) *bp++;
51 q |= (unsigned long long) *bp++ << 8;
52 q |= (unsigned long long) *bp++ << 16;
53 q |= (unsigned long long) *bp++ << 24;
54 q |= (unsigned long long) *bp++ << 32;
55 q |= (unsigned long long) *bp++ << 40;
56 q |= (unsigned long long) *bp++ << 48;
57 q |= (unsigned long long) *bp++ << 56;
58 *qp = q;
59 break;
60 default:
61 return -1;
62 }
63 }
64
65 return bp - src;
66 }
67
68 static int
69 bunpack(unsigned char *src, char *fmt, va_list va)
70 {
71 unsigned char *bp, *cp;
72 unsigned short *sp;
73 unsigned s;
74 unsigned long *lp, l;
75 unsigned long long *qp, q;
76 int n;
77
78 bp = src;
79 while (*fmt) {
80 switch (*fmt++) {
81 case '\'':
82 n = atoi(fmt);
83 while (isdigit(*fmt))
84 fmt++;
85 cp = va_arg(va, unsigned char *);
86 while (n--)
87 *cp++ = *bp++;
88 break;
89 case 'c':
90 cp = va_arg(va, unsigned char *);
91 *cp = *bp++;
92 break;
93 case 's':
94 sp = va_arg(va, unsigned short *);
95 s = (unsigned) *bp++ << 8;
96 s |= (unsigned) *bp++;
97 *sp = s;
98 break;
99 case 'l':
100 lp = va_arg(va, unsigned long *);
101 l = (unsigned long) *bp++ << 24;
102 l |= (unsigned long) *bp++ << 16;
103 l |= (unsigned long) *bp++ << 8;
104 l |= (unsigned long) *bp++;
105 *lp = l;
106 break;
107 case 'q':
108 qp = va_arg(va, unsigned long long *);
109 q = (unsigned long long) *bp++ << 56;
110 q |= (unsigned long long) *bp++ << 48;
111 q |= (unsigned long long) *bp++ << 40;
112 q |= (unsigned long long) *bp++ << 32;
113 q |= (unsigned long long) *bp++ << 24;
114 q |= (unsigned long long) *bp++ << 16;
115 q |= (unsigned long long) *bp++ << 8;
116 q |= (unsigned long long) *bp++;
117 *qp = q;
118 break;
119 default:
120 return -1;
121 }
122 }
123
124 return bp - src;
125 }
126
127 int
128 unpack(int order, unsigned char *src, char *fmt, ...)
129 {
130 int r;
131 int (*fn)(unsigned char *dst, char *fmt, va_list va);
132 va_list va;
133
134 va_start(va, fmt);
135 fn = (order == LITTLE_ENDIAN) ? lunpack : bunpack;
136 r = (*fn)(src, fmt, va);
137 va_end(va);
138
139 return r;
140 }