strlcat.c revision 706f2543 
1/*
2 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
9 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
11 * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
13 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
14 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17
18#ifdef HAVE_DIX_CONFIG_H
19#include <dix-config.h>
20#endif
21
22#include <sys/types.h>
23#include <string.h>
24#include "os.h"
25
26/*
27 * Appends src to string dst of size siz (unlike strncat, siz is the
28 * full size of dst, not space left).  At most siz-1 characters
29 * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
30 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
31 * If retval >= siz, truncation occurred.
32 */
33size_t
34strlcat(char *dst, const char *src, size_t siz)
35{
36	register char *d = dst;
37	register const char *s = src;
38	register size_t n = siz;
39	size_t dlen;
40
41	/* Find the end of dst and adjust bytes left but don't go past end */
42	while (n-- != 0 && *d != '\0')
43		d++;
44	dlen = d - dst;
45	n = siz - dlen;
46
47	if (n == 0)
48		return(dlen + strlen(s));
49	while (*s != '\0') {
50		if (n != 1) {
51			*d++ = *s;
52			n--;
53		}
54		s++;
55	}
56	*d = '\0';
57
58	return(dlen + (s - src));	/* count does not include NUL */
59}
60