xref: /freebsd/lib/libc/string/strlcat.c (revision ba840c782f16e4442c74f06fb17abaa2d9e3dec7)
1ba840c78SXin LI /*	$OpenBSD: strlcat.c,v 1.13 2005/08/08 08:05:37 espie Exp $	*/
2a41df9e3SWarner Losh 
3a41df9e3SWarner Losh /*
4a41df9e3SWarner Losh  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
5a41df9e3SWarner Losh  *
6ba840c78SXin LI  * Permission to use, copy, modify, and distribute this software for any
7ba840c78SXin LI  * purpose with or without fee is hereby granted, provided that the above
8ba840c78SXin LI  * copyright notice and this permission notice appear in all copies.
9a41df9e3SWarner Losh  *
10ba840c78SXin LI  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11ba840c78SXin LI  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12ba840c78SXin LI  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13ba840c78SXin LI  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14ba840c78SXin LI  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15ba840c78SXin LI  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16ba840c78SXin LI  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17a41df9e3SWarner Losh  */
18a41df9e3SWarner Losh 
19de5fe5d5SDavid E. O'Brien #include <sys/cdefs.h>
20de5fe5d5SDavid E. O'Brien __FBSDID("$FreeBSD$");
21a41df9e3SWarner Losh 
22a41df9e3SWarner Losh #include <sys/types.h>
23a41df9e3SWarner Losh #include <string.h>
24a41df9e3SWarner Losh 
25a41df9e3SWarner Losh /*
26a41df9e3SWarner Losh  * Appends src to string dst of size siz (unlike strncat, siz is the
27a41df9e3SWarner Losh  * full size of dst, not space left).  At most siz-1 characters
28420923e9SChris D. Faulhaber  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
296979f76fSKris Kennaway  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
306979f76fSKris Kennaway  * If retval >= siz, truncation occurred.
31a41df9e3SWarner Losh  */
326979f76fSKris Kennaway size_t
33ba840c78SXin LI strlcat(char *dst, const char *src, size_t siz)
34a41df9e3SWarner Losh {
358fb3f3f6SDavid E. O'Brien 	char *d = dst;
368fb3f3f6SDavid E. O'Brien 	const char *s = src;
378fb3f3f6SDavid E. O'Brien 	size_t n = siz;
38a41df9e3SWarner Losh 	size_t dlen;
39a41df9e3SWarner Losh 
40d64292d2SWarner Losh 	/* Find the end of dst and adjust bytes left but don't go past end */
41420923e9SChris D. Faulhaber 	while (n-- != 0 && *d != '\0')
42a41df9e3SWarner Losh 		d++;
43a41df9e3SWarner Losh 	dlen = d - dst;
44d64292d2SWarner Losh 	n = siz - dlen;
45a41df9e3SWarner Losh 
46a41df9e3SWarner Losh 	if (n == 0)
47a41df9e3SWarner Losh 		return(dlen + strlen(s));
48a41df9e3SWarner Losh 	while (*s != '\0') {
49a41df9e3SWarner Losh 		if (n != 1) {
50a41df9e3SWarner Losh 			*d++ = *s;
51a41df9e3SWarner Losh 			n--;
52a41df9e3SWarner Losh 		}
53a41df9e3SWarner Losh 		s++;
54a41df9e3SWarner Losh 	}
55a41df9e3SWarner Losh 	*d = '\0';
56a41df9e3SWarner Losh 
57a41df9e3SWarner Losh 	return(dlen + (s - src));	/* count does not include NUL */
58a41df9e3SWarner Losh }
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