StdLib/LibC/String/strsep.c

/*-
 * Copyright (c) 1990, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include  <LibConfig.h>

#include <sys/cdefs.h>
#include <string.h>
#include <stdio.h>

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strsep.c  8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */

/*
 * Get next token from string *stringp, where tokens are possibly-empty
 * strings separated by characters from delim.
 *
 * Writes NULs into the string at *stringp to end tokens.
 * delim need not remain constant from call to call.
 * On return, *stringp points past the last NUL written (if there might
 * be further tokens), or is NULL (if there are definitely no more tokens).
 *
 * If *stringp is NULL, strsep returns NULL.
 */
char *
strsep(
  register char **stringp,
  register const char *delim
  )
{
  register char *s;
  register const char *spanp;
  register int c, sc;
  char *tok;

  if ((s = *stringp) == NULL)
    return (NULL);
  for (tok = s;;) {
    c = *s++;
    spanp = delim;
    do {
      if ((sc = *spanp++) == c) {
        if (c == 0)
          s = NULL;
        else
          s[-1] = 0;
        *stringp = s;
        return (tok);
      }
    } while (sc != 0);
  }
  /* NOTREACHED */
}