xref: /freebsd/contrib/tcpdump/missing/strlcat.c (revision b224af946a17b8e7a7b4942157556b5bc86dd6fb)
1 /*	$NetBSD: strlcat.c,v 1.5 1999/09/20 04:39:47 lukem Exp $	*/
2 /*	from OpenBSD: strlcat.c,v 1.2 1999/06/17 16:28:58 millert Exp	*/
3 
4 /*
5  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
20  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
21  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
22  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
25  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
26  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
27  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
28  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <config.h>
32 
33 #include <netdissect-stdinc.h>
34 
35 #include <string.h>
36 
37 #include "netdissect.h"
38 
39 /*
40  * Appends src to string dst of size siz (unlike strncat, siz is the
41  * full size of dst, not space left).  At most siz-1 characters
42  * will be copied.  Always NUL terminates (unless siz == 0).
43  * Returns strlen(src); if retval >= siz, truncation occurred.
44  */
45 size_t
46 strlcat(char *dst, const char *src, size_t siz)
47 {
48 	char *d = dst;
49 	const char *s = src;
50 	size_t n = siz;
51 	size_t dlen;
52 
53 	/* Find the end of dst and adjust bytes left but don't go past end */
54 	while (*d != '\0' && n-- != 0)
55 		d++;
56 	dlen = d - dst;
57 	n = siz - dlen;
58 
59 	if (n == 0)
60 		return(dlen + strlen(s));
61 	while (*s != '\0') {
62 		if (n != 1) {
63 			*d++ = *s;
64 			n--;
65 		}
66 		s++;
67 	}
68 	*d = '\0';
69 
70 	return(dlen + (s - src));	/* count does not include NUL */
71 }
72