/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <string.h>
#ifdef __ANSI__
#include <sys/stdc.h>
#else
#include "strtok.h"
#define const
#define NULL 0
#endif

#if defined(LIBC_SCCS) && !defined(lint)
static const char sccsid[] = "%W% (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

/*
 * Get next token from string *stringp, where tokens are (possibly empty)
 * strings separated by characters from delim.  Tokens are separated
 * by exactly one delimiter iff the skip parameter is false; otherwise
 * they are separated by runs of characters from delim, because we
 * skip over any initial `delim' characters.
 *
 * Writes NULs into the string at *stringp to end tokens.
 * delim will usually, but need not, remain constant from call to call.
 * On return, *stringp points past the last NUL written (if there might
 * be further tokens), or is NULL (if there are definitely no more tokens).
 *
 * If *stringp is NULL, strtoken returns NULL.
 */
char *
strtoken(stringp, delim, skip)
	register char **stringp;
	register const char *delim;
	int skip;
{
	register char *s;
	register const char *spanp;
	register int c, sc;
	char *tok;

	if ((s = *stringp) == NULL)
		return (NULL);

	if (skip) {
		/*
		 * Skip (span) leading delimiters (s += strspn(s, delim)).
		 */
	cont:
		c = *s;
		for (spanp = delim; (sc = *spanp++) != 0;) {
			if (c == sc) {
				s++;
				goto cont;
			}
		}
		if (c == 0) {		/* no token found */
			*stringp = NULL;
			return (NULL);
		}
	}

	/*
	 * 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 (tok = s;;) {
		c = *s++;
		spanp = delim;
		do {
			if ((sc = *spanp++) == c) {
				if (c == 0)
					s = NULL;
				else
					s[-1] = 0;
				*stringp = s;
				return (tok);
			}
		} while (sc != 0);
	}
	/* NOTREACHED */
}