compat/strsep.c

   1 /*      $OpenBSD: strsep.c,v 1.6 2005/08/08 08:05:37 espie Exp $        */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  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 <string.h>
  33 #include <stdio.h>
  34
  35 /*
  36  * Get next token from string *stringp, where tokens are possibly-empty
  37  * strings separated by characters from delim.
  38  *
  39  * Writes NULs into the string at *stringp to end tokens.
  40  * delim need not remain constant from call to call.
  41  * On return, *stringp points past the last NUL written (if there might
  42  * be further tokens), or is NULL (if there are definitely no more tokens).
  43  *
  44  * If *stringp is NULL, strsep returns NULL.
  45  */
  46 char *
  47 strsep(char **stringp, const char *delim)
  48 {
  49         char *s;
  50         const char *spanp;
  51         int c, sc;
  52         char *tok;
  53
  54         if ((s = *stringp) == NULL)
  55                 return (NULL);
  56         for (tok = s;;) {
  57                 c = *s++;
  58                 spanp = delim;
  59                 do {
  60                         if ((sc = *spanp++) == c) {
  61                                 if (c == 0)
  62                                         s = NULL;
  63                                 else
  64                                         s[-1] = 0;
  65                                 *stringp = s;
  66                                 return (tok);
  67                         }
  68                 } while (sc != 0);
  69         }
  70         /* NOTREACHED */
  71 }