avr/getopt-min.c

   1 /*
   2  *      Minimum getopt, original version was:
   3  */
   4
   5 /*
   6         getopt -- public domain version of standard System V routine
   7
   8         Strictly enforces the System V Command Syntax Standard;
   9         provided by D A Gwyn of BRL for generic ANSI C implementations
  10 */
  11 /* $Id: getopt.c,v 1.2 1992/12/07 11:12:52 nickc Exp $ */
  12
  13 #include "common.h"             /* definition of FLASH */
  14 #include <string.h>
  15
  16 int     optind = 1;                     /* next argv[] index */
  17 char *optarg;           /* option parameter if any */
  18
  19
  20 int
  21 getopt(                                 /* returns letter, '?', EOF */
  22         int             argc,           /* argument count from main */
  23         char    *const argv[],  /* argument vector from main */
  24         const FLASH char *optstring )           /* allowed args, e.g. "ab:c" */
  25 {
  26         static int      sp = 1;         /* position within argument */
  27         int             osp;            /* saved `sp' for param test */
  28         int             c;              /* option letter */
  29         const FLASH char *cp;           /* -> option in `optstring' */
  30
  31         optarg = NULL;
  32
  33         if ( sp == 1 )                  /* fresh argument */
  34         {
  35                 if ( optind >= argc             /* no more arguments */
  36                   || argv[optind][0] != '-'     /* no more options */
  37                   || argv[optind][1] == '\0'    /* not option; stdin */
  38                    )
  39                         return -1;
  40         }
  41
  42         c = argv[optind][sp];           /* option letter */
  43         osp = sp++;                     /* get ready for next letter */
  44
  45         if ( argv[optind][sp] == '\0' ) /* end of argument */
  46         {
  47                 ++optind;               /* get ready for next try */
  48                 sp = 1;                 /* beginning of next argument */
  49         }
  50
  51         if ( c == ':'                   /* optstring syntax conflict */
  52           || (cp = strchr_P( optstring, c )) == NULL    /* not found */
  53            )
  54                 return '?';
  55
  56         if ( cp[1] == ':' )             /* option takes parameter */
  57         {
  58                 if ( osp != 1 )
  59                         return '?';
  60
  61                 if ( sp != 1 )          /* reset by end of argument */
  62                         return '?';
  63
  64                 if ( optind >= argc )
  65                         return '?';
  66
  67                 optarg = argv[optind];  /* make parameter available */
  68                 ++optind;               /* skip over parameter */
  69         }
  70
  71         return c;
  72 }