lib/libc/string/stresep.c

   1 /*      $NetBSD: stresep.c,v 1.2 2007/12/06 22:07:07 seb 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 <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)strsep.c    8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: stresep.c,v 1.2 2007/12/06 22:07:07 seb Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42
  43 #include <assert.h>
  44 #include <string.h>
  45
  46 #ifdef __weak_alias
  47 __weak_alias(stresep,_stresep)
  48 #endif
  49
  50 /*
  51  * Get next token from string *stringp, where tokens are possibly-empty
  52  * strings separated by characters from delim. If esc is not NUL, then
  53  * the characters followed by esc are ignored and are not taken into account
  54  * when splitting the string.
  55  *
  56  * Writes NULs into the string at *stringp to end tokens.
  57  * delim need not remain constant from call to call.
  58  * On return, *stringp points past the last NUL written (if there might
  59  * be further tokens), or is NULL (if there are definitely no more tokens).
  60  *
  61  * If *stringp is NULL, stresep returns NULL.
  62  */
  63 char *
  64 stresep(char **stringp, const char *delim, int esc)
  65 {
  66         char *s;
  67         const char *spanp;
  68         int c, sc;
  69         char *tok;
  70
  71         _DIAGASSERT(stringp != NULL);
  72         _DIAGASSERT(delim != NULL);
  73
  74         if ((s = *stringp) == NULL)
  75                 return NULL;
  76         for (tok = s;;) {
  77                 c = *s++;
  78                 while (esc != '\0' && c == esc) {
  79                         (void)strcpy(s - 1, s);
  80                         c = *s++;
  81                 }
  82                 spanp = delim;
  83                 do {
  84                         if ((sc = *spanp++) == c) {
  85                                 if (c == 0)
  86                                         s = NULL;
  87                                 else
  88                                         s[-1] = 0;
  89                                 *stringp = s;
  90                                 return tok;
  91                         }
  92                 } while (sc != 0);
  93         }
  94 }