strlcat.c revision 157016 
1/*	$OpenBSD: strlcat.c,v 1.13 2005/08/08 08:05:37 espie Exp $	*/
2
3/*
4 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19/* OPENBSD ORIGINAL: lib/libc/string/strlcat.c */
20
21#include "includes.h"
22#ifndef HAVE_STRLCAT
23
24#include <sys/types.h>
25#include <string.h>
26
27/*
28 * Appends src to string dst of size siz (unlike strncat, siz is the
29 * full size of dst, not space left).  At most siz-1 characters
30 * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
31 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
32 * If retval >= siz, truncation occurred.
33 */
34size_t
35strlcat(char *dst, const char *src, size_t siz)
36{
37	char *d = dst;
38	const char *s = src;
39	size_t n = siz;
40	size_t dlen;
41
42	/* Find the end of dst and adjust bytes left but don't go past end */
43	while (n-- != 0 && *d != '\0')
44		d++;
45	dlen = d - dst;
46	n = siz - dlen;
47
48	if (n == 0)
49		return(dlen + strlen(s));
50	while (*s != '\0') {
51		if (n != 1) {
52			*d++ = *s;
53			n--;
54		}
55		s++;
56	}
57	*d = '\0';
58
59	return(dlen + (s - src));	/* count does not include NUL */
60}
61
62#endif /* !HAVE_STRLCAT */
63