clib/strsep.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "config.h"
  35
  36 #if defined(LIBC_SCCS) && !defined(lint)
  37 static const char sccsid[] = "@(#)strsep.c      8.1 (Berkeley) 6/4/93";
  38 #endif /* LIBC_SCCS and not lint */
  39
  40 #include <string.h>
  41 #include <stdio.h>
  42
  43 /*
  44  * Get next token from string *stringp, where tokens are possibly-empty
  45  * strings separated by characters from delim.
  46  *
  47  * Writes NULs into the string at *stringp to end tokens.
  48  * delim need not remain constant from call to call.
  49  * On return, *stringp points past the last NUL written (if there might
  50  * be further tokens), or is NULL (if there are definitely no more tokens).
  51  *
  52  * If *stringp is NULL, strsep returns NULL.
  53  *
  54  * PUBLIC: #ifndef HAVE_STRSEP
  55  * PUBLIC: char *strsep __P((char **, const char *));
  56  * PUBLIC: #endif
  57  */
  58 char *
  59 strsep(stringp, delim)
  60         register char **stringp;
  61         register const char *delim;
  62 {
  63         register char *s;
  64         register const char *spanp;
  65         register int c, sc;
  66         char *tok;
  67
  68         if ((s = *stringp) == NULL)
  69                 return (NULL);
  70         for (tok = s;;) {
  71                 c = *s++;
  72                 spanp = delim;
  73                 do {
  74                         if ((sc = *spanp++) == c) {
  75                                 if (c == 0)
  76                                         s = NULL;
  77                                 else
  78                                         s[-1] = 0;
  79                                 *stringp = s;
  80                                 return (tok);
  81                         }
  82                 } while (sc != 0);
  83         }
  84         /* NOTREACHED */
  85 }