/* vi: set tabstop=4 shiftwidth=4: */

/*
 * $Id: options.c,v 1.2 1996/12/28 22:11:21 schweikh Exp $
 */

#include <stdio.h>              /* EOF */
#include <string.h>             /* strchr */
#include "shutup.h"
#include "options.h"

/*
 * After get_opt returned EOF, argv[opt_ind] is the first non-option
 * argument (may be NULL). You can adjust main's argc and argv with
 * argc -= opt_ind; argv += opt_ind. All non-options args now are in
 * argv[0..argc] where argv[argc] is NULL. Note that argv[0] no longer
 * is the program's invocation name but the first non-option arg.
 * If you need the original argv[0] you can process the non-options
 * with for (i = opt_ind; i < argc; ++i) { f (argv[i]); }
 */

/*@+charintliteral@ */
/*@+charint@ */
/*@-ptrarith@ */

char *opt_arg;
int opt_err = 1;                /* wheter we should diagnose invalid options */
int opt_opt;                    /* last known option returned we have
                                 * returned */

/*
 * opt_ind and subidx: together they
 * adress the next option character to process, i.e.
 * argv[opt_ind][subidx] is the next option char to use.
 * opt_ind starts at 1 because 0 is the program name,
 * subidx starts at 1 because 0 is the dash `-'.
 */
int opt_ind = 1;

int
get_opt (int argc, char **argv, const char *optstring)
/*
 * Simple getopt replacement.
 */
{
  static size_t subidx = 1;
  char *opt;

  /* End of the argv array or first non-option reached? */
  if (opt_ind == argc || *argv[opt_ind] != '-')
    {
      return EOF;               /* then we're finally done */
    }
  opt_opt = argv[opt_ind][subidx];
  if (opt_opt == 0)
    {                           /* found an unadorned `-' */
      return EOF;
    }
  opt = strchr (optstring, opt_opt);
  if (opt == NULL)
    {                           /* unknown option */
      if (opt_err != 0)
        {
          Fprintf (stderr, "illegal option -- %c\n", opt_opt);
        }
      ++subidx;
      if (argv[opt_ind][subidx] == 0)
        {                       /* end of current arg reached */
          subidx = 1;
          ++opt_ind;
        }
      return '?';
    }
  else
    {                           /* known option */
      if (opt[1] == ':')
        {                       /* takes an arg */
          if (argv[opt_ind][subidx + 1] != 0)
            {                   /* immediate arg */
              opt_arg = argv[opt_ind++] + subidx + 1;
              subidx = 1;
              return opt_opt;
            }
          else
            {                   /* arg is next element in argv[] */
              ++opt_ind;
              if (argv[opt_ind] == NULL)
                {               /* end of argv[] reached */
                  if (opt_err != 0)
                    {
                      Fprintf (stderr,
                               "option %c requires an argument\n", opt_opt);
                    }
                  return '?';   /* next call returns EOF */
                }
              if (argv[opt_ind][0] == '-' && argv[opt_ind][1] != 0)
                {
                  /* arg is other than `-' by itself */
                  if (opt_err != 0)
                    {
                      Fprintf (stderr,
                               "option %c requires an argument\n", opt_opt);
                    }
                  subidx = 1;
                  return '?';
                }
              else
                {
                  opt_arg = argv[opt_ind++];
                  subidx = 1;
                  return opt_opt;
                }
            }
        }
      else
        {                       /* takes no arg */
          ++subidx;
          if (argv[opt_ind][subidx] == 0)
            {                   /* end of current arg reached */
              subidx = 1;
              ++opt_ind;
            }
          return opt_opt;
        }
    }
}