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/*	$OpenBSD: strlcat.c,v 1.19 2019/01/25 00:19:25 millert Exp $	*/ 

/*
 * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org> 
 *
 * 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 <string.h>

/*
 * Appends src to string dst of size dsize (unlike strncat, dsize is the 
 * full size of dst, not space left).  At most dsize-1 characters 
 * will be copied.  Always NUL terminates (unless dsize <= strlen(dst)). 
 * Returns strlen(src) + MIN(dsize, strlen(initial dst)). 
 * If retval >= dsize, truncation occurred. 
 */
size_t
strlcat(char *dst, const char *src, size_t dsize) 
{
	const char *odst = dst; 
	const char *osrc = src; 
	size_t n = dsize; 
	size_t dlen; 

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

	if (n-- == 0) 
		return(dlen + strlen(src)); 
	while (*src != '\0') { 
		if (n != 0) { 
			*dst++ = *src; 
			n--; 
		} 
		src++; 
	} 
	*dst = '\0'; 

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