pack.c - scc - simple c99 compiler
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       ---
       pack.c (2141B)
       ---
            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 lpack(unsigned char *dst, char *fmt, va_list va)
           11 {
           12         unsigned char *bp, *cp;
           13         unsigned s;
           14         unsigned long l;
           15         unsigned long long q;
           16         int n;
           17 
           18         bp = dst;
           19         while (*fmt) {
           20                 switch (*fmt++) {
           21                 case '\'':
           22                         n = atoi(fmt);
           23                         while (isdigit(*fmt))
           24                                 fmt++;
           25                         cp = va_arg(va, unsigned char *);
           26                         while (n--)
           27                                 *bp++ = *cp++;
           28                         break;
           29                 case 'c':
           30                         *bp++ = va_arg(va, unsigned);
           31                         break;
           32                 case 's':
           33                         s = va_arg(va, unsigned);
           34                         *bp++ = s;
           35                         *bp++ = s >> 8;
           36                         break;
           37                 case 'l':
           38                         l = va_arg(va, unsigned long);
           39                         *bp++ = l;
           40                         *bp++ = l >> 8;
           41                         *bp++ = l >> 16;
           42                         *bp++ = l >> 24;
           43                         break;
           44                 case 'q':
           45                         q = va_arg(va, unsigned long long);
           46                         *bp++ = q;
           47                         *bp++ = q >> 8;
           48                         *bp++ = q >> 16;
           49                         *bp++ = q >> 24;
           50                         *bp++ = q >> 32;
           51                         *bp++ = q >> 40;
           52                         *bp++ = q >> 48;
           53                         *bp++ = q >> 56;
           54                         break;
           55                 default:
           56                         return -1;
           57                 }
           58         }
           59 
           60         return bp - dst;
           61 }
           62 
           63 static int
           64 bpack(unsigned char *dst, char *fmt, va_list va)
           65 {
           66         unsigned char *bp, *cp;
           67         unsigned s;
           68         unsigned long l;
           69         unsigned long long q;
           70         int n;
           71 
           72         bp = dst;
           73         while (*fmt) {
           74                 switch (*fmt++) {
           75                 case '\'':
           76                         n = atoi(fmt);
           77                         while (isdigit(*fmt))
           78                                 fmt++;
           79                         cp = va_arg(va, unsigned char *);
           80                         while (n--)
           81                                 *bp++ = *cp++;
           82                         break;
           83                 case 'c':
           84                         *bp++ = va_arg(va, unsigned);
           85                         break;
           86                 case 's':
           87                         s = va_arg(va, unsigned);
           88                         *bp++ = s >> 8;
           89                         *bp++ = s;
           90                         break;
           91                 case 'l':
           92                         l = va_arg(va, unsigned long);
           93                         *bp++ = l >> 24;
           94                         *bp++ = l >> 16;
           95                         *bp++ = l >> 8;
           96                         *bp++ = l;
           97                         break;
           98                 case 'q':
           99                         q = va_arg(va, unsigned long long);
          100                         *bp++ = q >> 56;
          101                         *bp++ = q >> 48;
          102                         *bp++ = q >> 40;
          103                         *bp++ = q >> 32;
          104                         *bp++ = q >> 24;
          105                         *bp++ = q >> 16;
          106                         *bp++ = q >> 8;
          107                         *bp++ = q;
          108                         break;
          109                 default:
          110                         return -1;
          111                 }
          112         }
          113 
          114         return bp - dst;
          115 }
          116 
          117 int
          118 pack(int order, unsigned char *dst, char *fmt, ...)
          119 {
          120         int r;
          121         int (*fn)(unsigned char *dst, char *fmt, va_list va);
          122         va_list va;
          123 
          124         va_start(va, fmt);
          125         fn = (order == LITTLE_ENDIAN) ? lpack : bpack;
          126         r = (*fn)(dst, fmt, va);
          127         va_end(va);
          128 
          129         return r;
          130 }