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