1/*	$NetBSD: strlcat.c,v 1.4 2013/01/23 07:57:27 matt Exp $	*/
2/*	$OpenBSD: strlcat.c,v 1.10 2003/04/12 21:56:39 millert Exp $	*/
3
4/*
5 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
12 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
13 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
14 * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
16 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
17 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20#include "config.h"
21
22#if defined(LIBC_SCCS) && !defined(lint)
23__RCSID("$NetBSD: strlcat.c,v 1.4 2013/01/23 07:57:27 matt Exp $");
24#endif /* LIBC_SCCS and not lint */
25
26#include <sys/types.h>
27#include <assert.h>
28#include <string.h>
29
30#ifdef _LIBC
31# ifdef __weak_alias
32__weak_alias(strlcat, _strlcat)
33# endif
34#endif
35
36#if !HAVE_STRLCAT
37/*
38 * Appends src to string dst of size siz (unlike strncat, siz is the
39 * full size of dst, not space left).  At most siz-1 characters
40 * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
41 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
42 * If retval >= siz, truncation occurred.
43 */
44size_t
45strlcat(char *dst, const char *src, size_t siz)
46{
47#if 1
48	char *d = dst;
49	const char *s = src;
50	size_t n = siz;
51	size_t dlen;
52
53	_DIAGASSERT(dst != NULL);
54	_DIAGASSERT(src != NULL);
55
56	/* Find the end of dst and adjust bytes left but don't go past end */
57	while (n-- != 0 && *d != '\0')
58		d++;
59	dlen = d - dst;
60	n = siz - dlen;
61
62	if (n == 0)
63		return(dlen + strlen(s));
64	while (*s != '\0') {
65		if (n != 1) {
66			*d++ = *s;
67			n--;
68		}
69		s++;
70	}
71	*d = '\0';
72
73	return(dlen + (s - src));	/* count does not include NUL */
74#else
75	_DIAGASSERT(dst != NULL);
76	_DIAGASSERT(src != NULL);
77
78	/*
79	 * Find length of string in dst (maxing out at siz).
80	 */
81	size_t dlen = strnlen(dst, siz);
82
83	/*
84	 * Copy src into any remaining space in dst (truncating if needed).
85	 * Note strlcpy(dst, src, 0) returns strlen(src).
86	 */
87	return dlen + strlcpy(dst + dlen, src, siz - dlen);
88#endif
89}
90#endif
91