strlcat.c revision 106121 
1/*	$OpenBSD: strlcat.c,v 1.8 2001/05/13 15:40:15 deraadt Exp $	*/
2
3/*
4 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
5 * 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. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
19 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
20 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
21 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include "includes.h"
31#ifndef HAVE_STRLCAT
32
33#if defined(LIBC_SCCS) && !defined(lint)
34static char *rcsid = "$OpenBSD: strlcat.c,v 1.8 2001/05/13 15:40:15 deraadt Exp $";
35#endif /* LIBC_SCCS and not lint */
36
37#include <sys/types.h>
38#include <string.h>
39#include "strlcat.h"
40
41/*
42 * Appends src to string dst of size siz (unlike strncat, siz is the
43 * full size of dst, not space left).  At most siz-1 characters
44 * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
45 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
46 * If retval >= siz, truncation occurred.
47 */
48size_t
49strlcat(dst, src, siz)
50	char *dst;
51	const char *src;
52	size_t siz;
53{
54	register char *d = dst;
55	register const char *s = src;
56	register size_t n = siz;
57	size_t dlen;
58
59	/* Find the end of dst and adjust bytes left but don't go past end */
60	while (n-- != 0 && *d != '\0')
61		d++;
62	dlen = d - dst;
63	n = siz - dlen;
64
65	if (n == 0)
66		return(dlen + strlen(s));
67	while (*s != '\0') {
68		if (n != 1) {
69			*d++ = *s;
70			n--;
71		}
72		s++;
73	}
74	*d = '\0';
75
76	return(dlen + (s - src));	/* count does not include NUL */
77}
78
79#endif /* !HAVE_STRLCAT */
80