/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strtok.c	5.7 (Berkeley) 06/01/90";
#endif /* LIBC_SCCS and not lint */

#include <stddef.h>
#include <string.h>

char *
strtok(s, delim)
	register char *s, *delim;
{
	register char *spanp;
	register int c, sc;
	char *tok;
	static char *last;


	if (s == NULL && (s = last) == NULL)
		return (NULL);

	/*
	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
	 */
cont:
	c = *s++;
	for (spanp = delim; (sc = *spanp++) != 0;) {
		if (c == sc)
			goto cont;
	}

	if (c == 0) {		/* no non-delimiter characters */
		last = NULL;
		return (NULL);
	}
	tok = s - 1;

	/*
	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
	 * Note that delim must have one NUL; we stop if we see that, too.
	 */
	for (;;) {
		c = *s++;
		spanp = delim;
		do {
			if ((sc = *spanp++) == c) {
				if (c == 0)
					s = NULL;
				else
					s[-1] = 0;
				last = s;
				return (tok);
			}
		} while (sc != 0);
	}
	/* NOTREACHED */
}