/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
static char sccsid[] = "@(#)getsubopt.c	5.2 (Berkeley) 02/24/91";
#endif /* not lint */

#include <unistd.h>
#include <stdlib.h>

/*
 * The SVID interface to getsubopt provides no way of figuring out which
 * part of the suboptions list wasn't matched.  This makes error messages
 * tricky...  The extern variable suboptarg is a pointer to the token
 * which didn't match.
 */
char *suboptarg;

getsubopt(optionp, tokens, valuep)
	register char **optionp, **valuep;
	register char * const *tokens;
{
	register int cnt;
	register char *p;

	suboptarg = *valuep = NULL;

	if (!optionp || !*optionp)
		return(-1);

	/* skip leading white-space, commas */
	for (p = *optionp; *p && (*p == ',' || *p == ' ' || *p == '\t'); ++p);

	if (!*p) {
		*optionp = p;
		return(-1);
	}

	/* save the start of the token, and skip the rest of the token. */
	for (suboptarg = p;
	    *++p && *p != ',' && *p != '=' && *p != ' ' && *p != '\t';);

	if (*p) {
		/*
		 * If there's an equals sign, set the value pointer, and
		 * skip over the value part of the token.  Terminate the
		 * token.
		 */
		if (*p == '=') {
			*p = '\0';
			for (*valuep = ++p;
			    *p && *p != ',' && *p != ' ' && *p != '\t'; ++p);
			if (*p) 
				*p++ = '\0';
		} else
			*p++ = '\0';
		/* Skip any whitespace or commas after this token. */
		for (; *p && (*p == ',' || *p == ' ' || *p == '\t'); ++p);
	}

	/* set optionp for next round. */
	*optionp = p;

	for (cnt = 0; *tokens; ++tokens, ++cnt)
		if (!strcmp(suboptarg, *tokens))
			return(cnt);
	return(-1);
}