/*	$OpenBSD: pcap_strlcat.c,v 1.15 2015/03/02 21:41:08 millert 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.

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <stddef.h>

#include <string.h>

#include "portability.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

pcap_strlcat(char * restrict dst, const char * restrict 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 */

}