glibc/string/strtok.c

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1995-02-18 01:27:10 +00:00
/* 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 <ansidecl.h>
#include <errno.h>
#include <string.h>
static char *olds = NULL;
/* 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 *
DEFUN(strtok, (s, delim),
register char *s AND register CONST char *delim)
{
char *token;
if (s == NULL)
{
if (olds == NULL)
{
errno = EINVAL;
return NULL;
}
else
s = olds;
}
/* Scan leading delimiters. */
s += strspn(s, delim);
if (*s == '\0')
{
olds = NULL;
return NULL;
}
/* Find the end of the token. */
token = s;
s = strpbrk(token, delim);
if (s == NULL)
/* This token finishes the string. */
olds = NULL;
else
{
/* Terminate the token and make OLDS point past it. */
*s = '\0';
olds = s + 1;
}
return token;
}