lib/libc/string/strtok_r.c

   1 /*      $NetBSD: strtok_r.c,v 1.9 2003/08/07 16:43:53 agc Exp $ */
   2
   3 /*
   4  * Copyright (c) 1988 Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char *sccsid = "@(#)strtok.c     5.8 (Berkeley) 2/24/91";
  36 #else
  37 __RCSID("$NetBSD: strtok_r.c,v 1.9 2003/08/07 16:43:53 agc Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42
  43 #include <assert.h>
  44 #include <string.h>
  45
  46 #ifdef __weak_alias
  47 __weak_alias(strtok_r,_strtok_r)
  48 #endif
  49
  50 char *
  51 strtok_r(s, delim, lasts)
  52         char *s;
  53         const char *delim;
  54         char **lasts;
  55 {
  56         const char *spanp;
  57         int c, sc;
  58         char *tok;
  59
  60         /* s may be NULL */
  61         _DIAGASSERT(delim != NULL);
  62         _DIAGASSERT(lasts != NULL);
  63
  64         if (s == NULL && (s = *lasts) == NULL)
  65                 return (NULL);
  66
  67         /*
  68          * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
  69          */
  70 cont:
  71         c = *s++;
  72         for (spanp = delim; (sc = *spanp++) != 0;) {
  73                 if (c == sc)
  74                         goto cont;
  75         }
  76
  77         if (c == 0) {           /* no non-delimiter characters */
  78                 *lasts = NULL;
  79                 return (NULL);
  80         }
  81         tok = s - 1;
  82
  83         /*
  84          * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
  85          * Note that delim must have one NUL; we stop if we see that, too.
  86          */
  87         for (;;) {
  88                 c = *s++;
  89                 spanp = delim;
  90                 do {
  91                         if ((sc = *spanp++) == c) {
  92                                 if (c == 0)
  93                                         s = NULL;
  94                                 else
  95                                         s[-1] = 0;
  96                                 *lasts = s;
  97                                 return (tok);
  98                         }
  99                 } while (sc != 0);
 100         }
 101         /* NOTREACHED */
 102 }