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 = 0;                     /* 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;             /* 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         if (optind == 0) {              /* start a new argument scan */
  33                 optind = 1;
  34                 sp = 1;
  35         }
  36
  37         if ( sp == 1 )                  /* fresh argument */
  38         {
  39                 if ( optind >= argc             /* no more arguments */
  40                   || argv[optind][0] != '-'     /* no more options */
  41                   || argv[optind][1] == '\0'    /* not option; stdin */
  42                    )
  43                         return -1;
  44         }
  45
  46         c = argv[optind][sp];           /* option letter */
  47         osp = sp++;                     /* get ready for next letter */
  48
  49         if ( argv[optind][sp] == '\0' ) /* end of argument */
  50         {
  51                 ++optind;               /* get ready for next try */
  52                 sp = 1;                 /* beginning of next argument */
  53         }
  54
  55         if ( c == ':'                   /* optstring syntax conflict */
  56           || (cp = strchr_P( optstring, c )) == NULL    /* not found */
  57            )
  58                 return '?';
  59
  60         if ( cp[1] == ':' )             /* option takes parameter */
  61         {
  62                 if ( osp != 1 )
  63                         return '?';
  64
  65                 if ( sp != 1 )          /* reset by end of argument */
  66                         return '?';
  67
  68                 if ( optind >= argc )
  69                         return '?';
  70
  71                 optarg = argv[optind];  /* make parameter available */
  72                 ++optind;               /* skip over parameter */
  73         }
  74
  75         return c;
  76 }