uclibc-ng/libc/string/strtok.c

/* Copyright (C) 1991 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <string.h>


static char *olds = 0;

/* Parse S into tokens separated by characters in DELIM.
   If S is NULL, the last string strtok() was called with is
   used.  For example:
	char s[] = "-abc=-def";
	x = strtok(s, "-");		// x = "abc"
	x = strtok(NULL, "=-");		// x = "def"
	x = strtok(NULL, "=");		// x = NULL
		// s = "abc\0-def\0"
*/
char *strtok( register char *s, register const char *delim)
{
	char *token;

	if (s == 0) {
		if (olds == 0) {
			return 0;
		} else
			s = olds;
	}

	/* Scan leading delimiters.  */
	s += strspn(s, delim);
	if (*s == '\0') {
		olds = 0;
		return 0;
	}

	/* Find the end of the token.  */
	token = s;
	s = strpbrk(token, delim);
	if (s == 0)
		/* This token finishes the string.  */
		olds = 0;
	else {
		/* Terminate the token and make OLDS point past it.  */
		*s = '\0';
		olds = s + 1;
	}
	return token;
}