strtok_r.c

minix操作系统最新版本（3.1.1）的源代码

/*
 * Copyright (c) 1998 Softweyr LLC.  All rights reserved.
 *
 * strtok_r, from Berkeley strtok
 * Oct 13, 1998 by Wes Peters <[e-mail]>
 *
 * Copyright (c) 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notices, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notices, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *
 *	This product includes software developed by Softweyr LLC, the
 *      University of California, Berkeley, and its contributors.
 *
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY SOFTWEYR LLC, THE REGENTS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL SOFTWEYR LLC, THE
 * REGENTS, OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef lint
static const char rcsid[] =
  "$FreeBSD: src/lib/libc/string/strtok.c,v 1.2.6.1 2001/07/09 23:30:07 obrien Exp $";
#endif

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

char *
strtok_r(char *s, const char *delim, char **last)
{
    char *spanp;
    int c, sc;
    char *tok;

    if (s == NULL && (s = *last) == NULL)
    {
	return NULL;
    }

    /*
     * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
     */
cont:
    c = *s++;
    for (spanp = (char *)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 = (char *)delim;
	do
	{
	    if ((sc = *spanp++) == c)
	    {
		if (c == 0)
		{
		    s = NULL;
		}
		else
		{
		    char *w = s - 1;
		    *w = '\0';
		}
		*last = s;
		return tok;
	    }
	}
	while (sc != 0);
    }
    /* NOTREACHED */
}


#if 0
char *
strtok(char *s, const char *delim)
{
    static char *last;

    return strtok_r(s, delim, &last);
}
#endif

#if defined(DEBUG_STRTOK)

/*
 * Test the tokenizer.
 */
int
main()
{
    char test[80], blah[80];
    char *sep = "\\/:;=-";
    char *word, *phrase, *brkt, *brkb;

    printf("String tokenizer test:\n");

    strcpy(test, "This;is.a:test:of=the/string\\tokenizer-function.");

    for (word = strtok(test, sep);
	 word;
	 word = strtok(NULL, sep))
    {
	printf("Next word is \"%s\".\n", word);
    }

    phrase = "foo";

    strcpy(test, "This;is.a:test:of=the/string\\tokenizer-function.");

    for (word = strtok_r(test, sep, &brkt);
	 word;
	 word = strtok_r(NULL, sep, &brkt))
    {
	strcpy(blah, "blah:blat:blab:blag");

	for (phrase = strtok_r(blah, sep, &brkb);
	     phrase;
	     phrase = strtok_r(NULL, sep, &brkb))
	{
	    printf("So far we're at %s:%s\n", word, phrase);
	}
    }

    return 0;
}

#endif /* DEBUG_STRTOK */