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[z180-stamp.git] / avr / getopt-min.c

/*
 *	Minimum getopt, original version was:
 */

/*
	getopt -- public domain version of standard System V routine

	Strictly enforces the System V Command Syntax Standard;
	provided by D A Gwyn of BRL for generic ANSI C implementations
*/
/* $Id: getopt.c,v 1.2 1992/12/07 11:12:52 nickc Exp $ */

#include "common.h"		/* definition of FLASH */
#include <string.h>

int	optind = 1;			/* next argv[] index */
char *optarg;		/* option parameter if any */


int
getopt( 				/* returns letter, '?', EOF */
	int		argc,		/* argument count from main */
	char	*const argv[],	/* argument vector from main */
	const FLASH char *optstring )		/* allowed args, e.g. "ab:c" */
{
	static int	sp = 1;		/* position within argument */
	int		osp;		/* saved `sp' for param test */
	int		c;		/* option letter */
	const FLASH char *cp;		/* -> option in `optstring' */

	optarg = NULL;

	if ( sp == 1 )			/* fresh argument */
	{
		if ( optind >= argc		/* no more arguments */
		  || argv[optind][0] != '-'	/* no more options */
		  || argv[optind][1] == '\0'	/* not option; stdin */
		   )
			return -1;
	}

	c = argv[optind][sp];		/* option letter */
	osp = sp++;			/* get ready for next letter */

	if ( argv[optind][sp] == '\0' )	/* end of argument */
	{
		++optind;		/* get ready for next try */
		sp = 1;			/* beginning of next argument */
	}

	if ( c == ':'			/* optstring syntax conflict */
	  || (cp = strchr_P( optstring, c )) == NULL	/* not found */
	   )
		return '?';

	if ( cp[1] == ':' )		/* option takes parameter */
	{
		if ( osp != 1 )
			return '?';

		if ( sp != 1 )		/* reset by end of argument */
			return '?';

		if ( optind >= argc )
			return '?';

		optarg = argv[optind];	/* make parameter available */
		++optind;		/* skip over parameter */
	}

	return c;
}