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strncat.c revision 1.2.4.2
      1  1.2.4.2  yamt /*	$NetBSD: strncat.c,v 1.2.4.2 2014/05/22 11:26:30 yamt Exp $	*/
      2  1.2.4.2  yamt 
      3  1.2.4.2  yamt /*-
      4  1.2.4.2  yamt  * Copyright (c) 1990, 1993
      5  1.2.4.2  yamt  *	The Regents of the University of California.  All rights reserved.
      6  1.2.4.2  yamt  *
      7  1.2.4.2  yamt  * This code is derived from software contributed to Berkeley by
      8  1.2.4.2  yamt  * Chris Torek.
      9  1.2.4.2  yamt  *
     10  1.2.4.2  yamt  * Redistribution and use in source and binary forms, with or without
     11  1.2.4.2  yamt  * modification, are permitted provided that the following conditions
     12  1.2.4.2  yamt  * are met:
     13  1.2.4.2  yamt  * 1. Redistributions of source code must retain the above copyright
     14  1.2.4.2  yamt  *    notice, this list of conditions and the following disclaimer.
     15  1.2.4.2  yamt  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.2.4.2  yamt  *    notice, this list of conditions and the following disclaimer in the
     17  1.2.4.2  yamt  *    documentation and/or other materials provided with the distribution.
     18  1.2.4.2  yamt  * 3. Neither the name of the University nor the names of its contributors
     19  1.2.4.2  yamt  *    may be used to endorse or promote products derived from this software
     20  1.2.4.2  yamt  *    without specific prior written permission.
     21  1.2.4.2  yamt  *
     22  1.2.4.2  yamt  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  1.2.4.2  yamt  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  1.2.4.2  yamt  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  1.2.4.2  yamt  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  1.2.4.2  yamt  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  1.2.4.2  yamt  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  1.2.4.2  yamt  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  1.2.4.2  yamt  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  1.2.4.2  yamt  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  1.2.4.2  yamt  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  1.2.4.2  yamt  * SUCH DAMAGE.
     33  1.2.4.2  yamt  */
     34  1.2.4.2  yamt 
     35  1.2.4.2  yamt #include <sys/cdefs.h>
     36  1.2.4.2  yamt #if defined(LIBC_SCCS) && !defined(lint)
     37  1.2.4.2  yamt #if 0
     38  1.2.4.2  yamt static char sccsid[] = "@(#)strncat.c	8.1 (Berkeley) 6/4/93";
     39  1.2.4.2  yamt #else
     40  1.2.4.2  yamt __RCSID("$NetBSD: strncat.c,v 1.2.4.2 2014/05/22 11:26:30 yamt Exp $");
     41  1.2.4.2  yamt #endif
     42  1.2.4.2  yamt #endif /* LIBC_SCCS and not lint */
     43  1.2.4.2  yamt 
     44  1.2.4.2  yamt #if !defined(_KERNEL) && !defined(_STANDALONE)
     45  1.2.4.2  yamt #include <assert.h>
     46  1.2.4.2  yamt #include <string.h>
     47  1.2.4.2  yamt #else
     48  1.2.4.2  yamt #include <lib/libkern/libkern.h>
     49  1.2.4.2  yamt #endif
     50  1.2.4.2  yamt 
     51  1.2.4.2  yamt #ifdef _FORTIFY_SOURCE
     52  1.2.4.2  yamt #undef strncat
     53  1.2.4.2  yamt #endif
     54  1.2.4.2  yamt 
     55  1.2.4.2  yamt /*
     56  1.2.4.2  yamt  * Concatenate src on the end of dst.  At most strlen(dst)+n+1 bytes
     57  1.2.4.2  yamt  * are written at dst (at most n+1 bytes being appended).  Return dst.
     58  1.2.4.2  yamt  */
     59  1.2.4.2  yamt char *
     60  1.2.4.2  yamt strncat(char *dst, const char *src, size_t n)
     61  1.2.4.2  yamt {
     62  1.2.4.2  yamt 
     63  1.2.4.2  yamt 	_DIAGASSERT(dst != NULL);
     64  1.2.4.2  yamt 	_DIAGASSERT(src != NULL);
     65  1.2.4.2  yamt 
     66  1.2.4.2  yamt 	if (n != 0) {
     67  1.2.4.2  yamt 		char *d = dst;
     68  1.2.4.2  yamt 		const char *s = src;
     69  1.2.4.2  yamt 
     70  1.2.4.2  yamt 		while (*d != 0)
     71  1.2.4.2  yamt 			d++;
     72  1.2.4.2  yamt 		do {
     73  1.2.4.2  yamt 			if ((*d = *s++) == 0)
     74  1.2.4.2  yamt 				break;
     75  1.2.4.2  yamt 			d++;
     76  1.2.4.2  yamt 		} while (--n != 0);
     77  1.2.4.2  yamt 		*d = 0;
     78  1.2.4.2  yamt 	}
     79  1.2.4.2  yamt 	return (dst);
     80  1.2.4.2  yamt }
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