com32/lib/getopt.c

   1 /*
   2  * getopt.c
   3  *
   4  * Simple POSIX getopt(), no GNU extensions...
   5  */
   6
   7 #include <stdint.h>
   8 #include <unistd.h>
   9 #include <string.h>
  10
  11 char *optarg;
  12 int optind = 1;
  13 int opterr, optopt;
  14 static const char *__optptr;
  15
  16 int getopt(int argc, char * const *argv, const char *optstring)
  17 {
  18   const char *carg = argv[optind];
  19   const char *osptr;
  20   int opt;
  21
  22   /* We don't actually need argc */
  23   (void)argc;
  24
  25   /* First, eliminate all non-option cases */
  26
  27   if ( !carg || carg[0] != '-' || !carg[1] ) {
  28     return -1;
  29   }
  30
  31   if ( carg[1] == '-' && !carg[2] ) {
  32     optind++;
  33     return -1;
  34   }
  35
  36   if ( (uintptr_t)(__optptr-carg) > (uintptr_t)strlen(carg) )
  37     __optptr = carg+1;  /* Someone frobbed optind, change to new opt. */
  38
  39   opt = *__optptr++;
  40
  41   if ( opt != ':' && (osptr = strchr(optstring, opt)) ) {
  42     if ( osptr[1] == ':' ) {
  43       if ( *__optptr ) {
  44         /* Argument-taking option with attached argument */
  45         optarg = (char *)__optptr;
  46         optind++;
  47       } else {
  48         /* Argument-taking option with non-attached argument */
  49         if ( argv[optind+1] ) {
  50           optarg = (char *)argv[optind+1];
  51           optind += 2;
  52         } else {
  53           /* Missing argument */
  54           return (optstring[0] == ':') ? ':' : '?';
  55         }
  56       }
  57       return opt;
  58     } else {
  59       /* Non-argument-taking option */
  60       /* __optptr will remember the exact position to resume at */
  61       if ( ! *__optptr )
  62         optind++;
  63       return opt;
  64     }
  65   } else {
  66     /* Unknown option */
  67     optopt = opt;
  68     if ( ! *__optptr )
  69       optind++;
  70     return '?';
  71   }
  72 }