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 * $FreeBSD: head/lib/libc/string/strlcat.c 189133 2009-02-28 05:15:02Z das $
19 */
20
21 #include <sys/types.h>
22 #include <string.h>
23
24 /*
25 * Appends src to string dst of size siz (unlike strncat, siz is the
26 * full size of dst, not space left). At most siz-1 characters
27 * will be copied. Always NUL terminates (unless siz <= strlen(dst)).
28 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
29 * If retval >= siz, truncation occurred.
30 */
31 size_t
strlcat(char * __restrict dst,const char * __restrict src,size_t siz)32 strlcat(char * __restrict dst, const char * __restrict src, size_t siz)
33 {
34 char *d = dst;
35 const char *s = src;
36 size_t n = siz;
37 size_t dlen;
38
39 /* Find the end of dst and adjust bytes left but don't go past end */
40 while (n-- != 0 && *d != '\0')
41 d++;
42 dlen = d - dst;
43 n = siz - dlen;
44
45 if (n == 0)
46 return(dlen + strlen(s));
47 while (*s != '\0') {
48 if (n != 1) {
49 *d++ = *s;
50 n--;
51 }
52 s++;
53 }
54 *d = '\0';
55
56 return(dlen + (s - src)); /* count does not include NUL */
57 }
58