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      1 /*	$NetBSD: stresep.c,v 1.4 2017/08/23 10:27:41 christos 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 1.4 2017/08/23 10:27:41 christos 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 	size_t l;
     70 	char *tok;
     71 
     72 	_DIAGASSERT(stringp != NULL);
     73 	_DIAGASSERT(delim != NULL);
     74 
     75 	if ((s = *stringp) == NULL)
     76 		return NULL;
     77 	l = strlen(s) + 1;
     78 	for (tok = s;;) {
     79 		c = *s++;
     80 		l--;
     81 		while (esc != '\0' && c == esc) {
     82 			memmove(s - 1, s, l);
     83 			c = *s++;
     84 			l--;
     85 		}
     86 		spanp = delim;
     87 		do {
     88 			if ((sc = *spanp++) == c) {
     89 				if (c == '\0')
     90 					s = NULL;
     91 				else
     92 					s[-1] = '\0';
     93 				*stringp = s;
     94 				return tok;
     95 			}
     96 		} while (sc != '\0');
     97 	}
     98 }
     99