getopt_tabified.c

#include "inc/getopt.h"

/* This function gets the next option letter from the console input.
   It is supposed to be equivalent to the UNIX getopt function.
   Options are preceeded by a dash, currently a slash is not allowed.
   Multiple options after one dash are valid, and arguments after
   the option with a colon between are supported.*/

/* Common varibles. */

int		opterr = 1,	/* error messages printed? default: yes */
		optind = 1,	/* index into parent argv vector  */
		optopt;		/* character checked for validity */

char	*optarg;	/* argument associated with option */

#define EMSG	""

char	*progname;	/* may also be defined elsewhere  */


static void
error(char *pch)	/* error message routine */
{
	if (!opterr)
		return;		/* without printing */

	fprintf(stderr, "%s: %s: %c\n",
			((NULL != progname) ? progname : "getopt"), pch, optopt);
}


int
getopt(int argc, char *argv[], char *ostr)
{
	static char		*place = EMSG;	/* option letter processing */
	char			*oli;			/* option letter list index */

	progname = argv[0];

	if (!*place)
	{	/* update scanning pointer */
		if (optind >= argc ||
			(*(place = argv[optind]) != '-' &&
			 *(place = argv[optind]) != '/') ||
			 !*++place)
		{
			return EOF;
		}
		if (*place == '-')
		{	/* found "--"; ignore; (end of options) */
			++optind;
			return EOF;
		}
	}

	/* option letter okay? */
	optopt = (int)*place;
	++place;
	oli = strchr(ostr, optopt);
	if ((optopt == (int)':') ||
		!(oli = strchr(ostr, optopt)))
	{
		if (!*place)
			++optind;

		error("illegal option");
		return BADCH;
	}

	if (*++oli != ':')	/* Check for argument after option */
	{	/* don't need argument */
		optarg = NULL;
		if (!*place)
			++optind;
	}
	else
	{	/* need an argument */
		if (*place)
			optarg = place;		/* no white space */
		else
			if (argc <= ++optind)
			{	/* no arg */
				place = EMSG;
				error("option requires an argument");
				return BADCH;
			}
			else
				optarg = argv[optind];	/* white space */
		place = EMSG;
		++optind;
	}
	return optopt;	/* return option letter */
}

/* vi: set sw=4 ts=4 sts=4 noet :iv */