libc/upstream-openbsd/lib/libc/string/wcslcpy.c

/*	$OpenBSD: wcslcpy.c,v 1.7 2015/09/12 16:23:14 guenther Exp $	*/

/*
 * Copyright (c) 1998, 2015 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

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

/*
 * Copy string src to buffer dst of size dsize.  At most dsize-1
 * chars will be copied.  Always NUL terminates (unless dsize == 0).
 * Returns wcslen(src); if retval >= dsize, truncation occurred.
 */
size_t
wcslcpy(wchar_t *dst, const wchar_t *src, size_t dsize)
{
	const wchar_t *osrc = src;
	size_t nleft = dsize;

	/* Copy as many bytes as will fit. */
	if (nleft != 0) {
		while (--nleft != 0) {
			if ((*dst++ = *src++) == L'\0')
				break;
		}
	}

	/* Not enough room in dst, add NUL and traverse rest of src. */
	if (nleft == 0) {
		if (dsize != 0)
			*dst = L'\0';		/* NUL-terminate dst */
		while (*src++)
			;
	}

	return(src - osrc - 1);	/* count does not include NUL */
}
DEF_WEAK(wcslcpy);