/* $Id: getopt.c,v 1.2 1993/06/11 16:31:57 Rhialto Exp $
 * $Log: getopt.c,v $
 * Revision 1.2  1993/06/11  16:31:57  Rhialto
 * First real RCS checkin
 *
 */
/*
 * getopt.h - Get next option letter from argument vector. v1.1
 * 12-Dec-1987	aklevin
 */

#define GETOPT_H

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

/*
 * optarg points to an option's argument (if any). optind holds the index
 * of the next argument vector element to parse. Once all options have
 * been parsed, points to the first non-option argument. [If (optind >
 * argc) then there are no more arguments]. opterr, if set to 0 will
 * suppress getopt's error messages (default is 1). optopt, while not
 * usually documented, is used here to return the actual option character
 * found, even when getopt itself returns '?'.
 */
char	       *optarg;
int		optind = 1,
		opterr = 1,
		optopt;

int
getopt(argc, argv, optstring)
int		argc;
char	       *argv[],
	       *optstring;
{

    int 	    any_more,
		    i,
		    result;
    static int	    opthold,
		    optsub = 1;

    /* Reset optarg upon entry	*/
    optarg = NULL;

    /* Reset optsub if caller has changed optind.	 */
    if (optind != opthold)
	optsub = 1;

    /* Look at each element of the argument vector still unparsed.  */
    for (; optind < argc; optind++) {
	/*
	 * Done if a non-option argument or single dash is reached.
	 * However, don't skip over said argument.
	 */
	if (argv[optind][0] != '-' || argv[optind][1] == '\0')
	    break;

	/* Got an option.  */

	/* Done if "--" is reached.  Skip over it, too.  */
	if (argv[optind][1] == '-') {
	    optind++;
	    break;
	}
	/* Look at each character in optstring.  */
	for (i = 0; i < strlen(optstring); i++) {
	    if ((optopt = argv[optind][optsub]) != optstring[i])
		continue;

	    /* Got a match.  */

	    /* Are there any more chars in this option?  e.g. `-abc'  */
	    any_more = strlen(argv[optind]) - optsub - 1;

	    /* Does this option require an argument?  */
	    if (optstring[i + 1] == ':') {

		/* Yes.  If this is the last argument, complain.  */
		if (optind == argc - 1 && !any_more) {
		    if (opterr)
			fprintf(stderr, "%s: `-%c' option requires an argument.\n", argv[0], optopt);
		    optind++;
		    result = '?';
		    goto leave;
		}
		/* end if (opt */
		/*
		 * Qualifier is either rest of this argument (if any) or
		 * next argument.
		 */
		else {
		    if (!any_more)
			optarg = argv[++optind];
		    else
			optarg = &argv[optind][optsub + 1];
		    optind++;
		    optsub = 1;
		}		/* end else */
	    }
	     /* end if (opt */
	    else {
		/* No argument; just adjust indices.  */
		/* Advance to next argument.  */
		if (!any_more) {
		    optind++;
		    optsub = 1;
		}
		/* end if (! */
		 /* Advance to next character.	 */
		else
		    optsub++;
	    }			/* end else */
	    result = optopt;
	    goto leave;
	}			/* end for (i=0 */
	if (opterr)
	    fprintf(stderr, "%s: Unrecognized option `-%c'.\n", argv[0], optopt);
	if (strlen(argv[optind]) - optsub - 1)
	    optsub++;
	else {
	    optind++;
	    optsub = 1;
	}
	result = '?';
	goto leave;
    }				/* end for ( ; */
    result = EOF;
leave:
    opthold = optind;
    return (result);
}				/* end getopt() */