/*
   **   @(#)getopt.c    2.5 (smail) 9/15/87
 */

/*
 * Here's something you've all been waiting for:  the AT&T public domain
 * source for getopt(3).  It is the code which was given out at the 1985
 * UNIFORUM conference in Dallas.  I obtained it by electronic mail
 * directly from AT&T.  The people there assure me that it is indeed
 * in the public domain.
 *
 * There is no manual page.  That is because the one they gave out at
 * UNIFORUM was slightly different from the current System V Release 2
 * manual page.  The difference apparently involved a note about the
 * famous rules 5 and 6, recommending using white space between an option
 * and its first argument, and not grouping options that have arguments.
 * Getopt itself is currently lenient about both of these things White
 * space is allowed, but not mandatory, and the last option in a group can
 * have an argument.  That particular version of the man page evidently
 * has no official existence, and my source at AT&T did not send a copy.
 * The current SVR2 man page reflects the actual behavor of this getopt.
 * However, I am not about to post a copy of anything licensed by AT&T.
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

/*LINTLIBRARY */
#define EOF	(-1)
#define ERR(s, c)\
  if(opterr) { fprintf(stderr, "%s%s%lc\n", argv[0], s, c); }

int opterr = 1;
int optind = 1;
int optopt;
char *optarg;

int
getopt (int argc, char *const *argv, const char *opts)
{
  static int sp = 1;
  register long int c;
  register char *cp;

  if (sp == 1)
    if (optind >= argc ||
	argv[optind][0] != '-' || argv[optind][1] == '\0')
      return (EOF);
    else if (strcmp (argv[optind], "--") == NULL)
      {
	optind++;
	return (EOF);
      }
  optopt = c = argv[optind][sp];
  if (c == ':' || (cp = index (opts, c)) == NULL)
    {
      ERR (": illegal option -- ", c);
      if (argv[optind][++sp] == '\0')
	{
	  optind++;
	  sp = 1;
	}
      return ('?');
    }
  if (*++cp == ':')
    {
      if (argv[optind][sp + 1] != '\0')
	optarg = &argv[optind++][sp + 1];
      else if (++optind >= argc)
	{
	  ERR (": option requires an argument -- ", c);
	  sp = 1;
	  return ('?');
	}
      else
	optarg = argv[optind++];
      sp = 1;
    }
  else
    {
      if (argv[optind][++sp] == '\0')
	{
	  sp = 1;
	  optind++;
	}
      optarg = NULL;
    }
  return (c);
}