lib/libc/string/wcslcat.c
/*	$NetBSD: wcslcat.c,v 1.2 2001/01/03 14:33:02 lukem Exp $	*/
/*	from OpenBSD: strlcat.c,v 1.3 2000/11/24 11:10:02 itojun Exp 	*/

/*
 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: wcslcat.c,v 1.2 2001/01/03 14:33:02 lukem Exp $");
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <assert.h>
#include <wchar.h>

/*
 * Appends src to string dst of size siz (unlike wcsncat, siz is the
 * full size of dst, not space left).  At most siz-1 characters
 * will be copied.  Always NUL terminates (unless siz == 0).
 * Returns wcslen(initial dst) + wcslen(src); if retval >= siz,
 * truncation occurred.
 */
size_t
wcslcat(dst, src, siz)
	wchar_t *dst;
	const wchar_t *src;
	size_t siz;
{
	wchar_t *d = dst;
	const wchar_t *s = src;
	size_t n = siz;
	size_t dlen;

	_DIAGASSERT(dst != NULL);
	_DIAGASSERT(src != NULL);

	/* Find the end of dst and adjust bytes left but don't go past end */
	while (*d != '\0' && n-- != 0)
		d++;
	dlen = d - dst;
	n = siz - dlen;

	if (n == 0)
		return(dlen + wcslen(s));
	while (*s != '\0') {
		if (n != 1) {
			*d++ = *s;
			n--;
		}
		s++;
	}
	*d = '\0';

	return(dlen + (s - src));	/* count does not include NUL */
}
