src/port/strsep.c

   1 /*
   2  * src/port/strsep.c
   3  *
   4  *      $OpenBSD: strsep.c,v 1.8 2015/08/31 02:53:57 guenther Exp $     */
   5
   6 /*-
   7  * Copyright (c) 1990, 1993
   8  *      The Regents of the University of California.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include "c.h"
  36
  37 /*
  38  * Get next token from string *stringp, where tokens are possibly-empty
  39  * strings separated by characters from delim.
  40  *
  41  * Writes NULs into the string at *stringp to end tokens.
  42  * delim need not remain constant from call to call.
  43  * On return, *stringp points past the last NUL written (if there might
  44  * be further tokens), or is NULL (if there are definitely no more tokens).
  45  *
  46  * If *stringp is NULL, strsep returns NULL.
  47  */
  48 char *
  49 strsep(char **stringp, const char *delim)
  50 {
  51         char       *s;
  52         const char *spanp;
  53         int                     c,
  54                                 sc;
  55         char       *tok;
  56
  57         if ((s = *stringp) == NULL)
  58                 return (NULL);
  59         for (tok = s;;)
  60         {
  61                 c = *s++;
  62                 spanp = delim;
  63                 do
  64                 {
  65                         if ((sc = *spanp++) == c)
  66                         {
  67                                 if (c == 0)
  68                                         s = NULL;
  69                                 else
  70                                         s[-1] = 0;
  71                                 *stringp = s;
  72                                 return (tok);
  73                         }
  74                 } while (sc != 0);
  75         }
  76         /* NOTREACHED */
  77 }