usr/src/lib/libbc/libc/gen/common/strtok.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*      Copyright (c) 1984 AT&T */
  23 /*        All Rights Reserved   */
  24
  25 #pragma ident   "%Z%%M% %I%     %E% SMI"  /* from S5R2 1.2 */
  26
  27 /*LINTLIBRARY*/
  28 /*
  29  * uses strpbrk and strspn to break string into tokens on
  30  * sequentially subsequent calls.  returns NULL when no
  31  * non-separator characters remain.
  32  * `subsequent' calls are calls with first argument NULL.
  33  */
  34
  35 #define NULL    (char*)0
  36
  37 extern int strspn();
  38 extern char *strpbrk();
  39
  40 char *
  41 strtok(string, sepset)
  42 char    *string, *sepset;
  43 {
  44         register char   *p, *q, *r;
  45         static char     *savept;
  46
  47         /*first or subsequent call*/
  48         p = (string == NULL)? savept: string;
  49
  50         if(p == 0)              /* return if no tokens remaining */
  51                 return(NULL);
  52
  53         q = p + strspn(p, sepset);      /* skip leading separators */
  54
  55         if(*q == '\0')          /* return if no tokens remaining */
  56                 return(NULL);
  57
  58         if((r = strpbrk(q, sepset)) == NULL)    /* move past token */
  59                 savept = 0;     /* indicate this is last token */
  60         else {
  61                 *r = '\0';
  62                 savept = ++r;
  63         }
  64         return(q);
  65 }