src/strsep.c

   1 /*-
   2  * Copyright (c) 1990 The Regents of the University of California.
   3  * 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 #if defined(LIBC_SCCS) && !defined(lint)
  35 /*static const char sccsid[] = "from: @(#)strsep.c      5.4 (Berkeley) 1/26/91";*/
  36 static char *rcsid = "$Id: strsep.c,v 2.0 2004-12-05 19:44:23 bjk Exp $";
  37 #endif                          /* LIBC_SCCS and not lint */
  38
  39 #include <string.h>             /* string.h */
  40
  41 /*
  42  * Get next token from string *stringp, where tokens are nonempty
  43  * strings separated by characters from delim.
  44  *
  45  * Writes NULs into the string at *stringp to end tokens.
  46  * delim need not remain constant from call to call.
  47  * On return, *stringp points past the last NUL written (if there might
  48  * be further tokens), or is NULL (if there are definitely no more tokens).
  49  *
  50  * If *stringp is NULL, strtoken returns NULL.
  51  */
  52 char *strsep(stringp, delim)
  53 register char **stringp;
  54 register const char *delim;
  55 {
  56     register char *s;
  57     register const char *spanp;
  58     register int c, sc;
  59     char *tok;
  60
  61     if ((s = *stringp) == NULL)
  62         return (NULL);
  63     for (tok = s;;) {
  64         c = *s++;
  65         spanp = delim;
  66         do {
  67             if ((sc = *spanp++) == c) {
  68                 if (c == 0)
  69                     s = NULL;
  70                 else
  71                     s[-1] = 0;
  72                 *stringp = s;
  73                 return (tok);
  74             }
  75         }
  76         while (sc != 0);
  77     }
  78     /*
  79      * NOTREACHED
  80      */
  81 }