xref: /freebsd/lib/libc/string/strncat.c (revision 8a16b7a18f5d0b031f09832fd7752fba717e2a97)
158f0484fSRodney W. Grimes /*-
2*8a16b7a1SPedro F. Giffuni  * SPDX-License-Identifier: BSD-3-Clause
3*8a16b7a1SPedro F. Giffuni  *
458f0484fSRodney W. Grimes  * Copyright (c) 1990, 1993
558f0484fSRodney W. Grimes  *	The Regents of the University of California.  All rights reserved.
658f0484fSRodney W. Grimes  *
758f0484fSRodney W. Grimes  * This code is derived from software contributed to Berkeley by
858f0484fSRodney W. Grimes  * Chris Torek.
958f0484fSRodney W. Grimes  *
1058f0484fSRodney W. Grimes  * Redistribution and use in source and binary forms, with or without
1158f0484fSRodney W. Grimes  * modification, are permitted provided that the following conditions
1258f0484fSRodney W. Grimes  * are met:
1358f0484fSRodney W. Grimes  * 1. Redistributions of source code must retain the above copyright
1458f0484fSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer.
1558f0484fSRodney W. Grimes  * 2. Redistributions in binary form must reproduce the above copyright
1658f0484fSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer in the
1758f0484fSRodney W. Grimes  *    documentation and/or other materials provided with the distribution.
183fb3b97cSEd Maste  * 3. Neither the name of the University nor the names of its contributors
1958f0484fSRodney W. Grimes  *    may be used to endorse or promote products derived from this software
2058f0484fSRodney W. Grimes  *    without specific prior written permission.
2158f0484fSRodney W. Grimes  *
2258f0484fSRodney W. Grimes  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
2358f0484fSRodney W. Grimes  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
2458f0484fSRodney W. Grimes  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
2558f0484fSRodney W. Grimes  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
2658f0484fSRodney W. Grimes  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
2758f0484fSRodney W. Grimes  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
2858f0484fSRodney W. Grimes  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
2958f0484fSRodney W. Grimes  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
3058f0484fSRodney W. Grimes  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
3158f0484fSRodney W. Grimes  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
3258f0484fSRodney W. Grimes  * SUCH DAMAGE.
3358f0484fSRodney W. Grimes  */
3458f0484fSRodney W. Grimes 
3558f0484fSRodney W. Grimes #if defined(LIBC_SCCS) && !defined(lint)
3658f0484fSRodney W. Grimes static char sccsid[] = "@(#)strncat.c	8.1 (Berkeley) 6/4/93";
3758f0484fSRodney W. Grimes #endif /* LIBC_SCCS and not lint */
3858f0484fSRodney W. Grimes #include <sys/cdefs.h>
39de5fe5d5SDavid E. O'Brien __FBSDID("$FreeBSD$");
40de5fe5d5SDavid E. O'Brien 
4158f0484fSRodney W. Grimes #include <string.h>
4258f0484fSRodney W. Grimes 
4358f0484fSRodney W. Grimes /*
4458f0484fSRodney W. Grimes  * Concatenate src on the end of dst.  At most strlen(dst)+n+1 bytes
4558f0484fSRodney W. Grimes  * are written at dst (at most n+1 bytes being appended).  Return dst.
4658f0484fSRodney W. Grimes  */
4758f0484fSRodney W. Grimes char *
48ad906968SRobert Drehmel strncat(char * __restrict dst, const char * __restrict src, size_t n)
4958f0484fSRodney W. Grimes {
5058f0484fSRodney W. Grimes 	if (n != 0) {
518fb3f3f6SDavid E. O'Brien 		char *d = dst;
528fb3f3f6SDavid E. O'Brien 		const char *s = src;
5358f0484fSRodney W. Grimes 
5458f0484fSRodney W. Grimes 		while (*d != 0)
5558f0484fSRodney W. Grimes 			d++;
5658f0484fSRodney W. Grimes 		do {
5758f0484fSRodney W. Grimes 			if ((*d = *s++) == 0)
5858f0484fSRodney W. Grimes 				break;
5958f0484fSRodney W. Grimes 			d++;
6058f0484fSRodney W. Grimes 		} while (--n != 0);
6158f0484fSRodney W. Grimes 		*d = 0;
6258f0484fSRodney W. Grimes 	}
6358f0484fSRodney W. Grimes 	return (dst);
6458f0484fSRodney W. Grimes }
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