xref: /netbsd-src/external/bsd/libpcap/dist/missing/strlcat.c (revision f73a5f05f638a81353839a8e4bfc90d1189181e7)
1*f73a5f05Schristos /*	$OpenBSD: strlcat.c,v 1.15 2015/03/02 21:41:08 millert Exp $	*/
24a71e5f3Schristos 
34a71e5f3Schristos /*
44a71e5f3Schristos  * Copyright (c) 1998, 2015 Todd C. Miller <Todd.Miller@courtesan.com>
54a71e5f3Schristos  *
64a71e5f3Schristos  * Permission to use, copy, modify, and distribute this software for any
74a71e5f3Schristos  * purpose with or without fee is hereby granted, provided that the above
84a71e5f3Schristos  * copyright notice and this permission notice appear in all copies.
94a71e5f3Schristos  *
104a71e5f3Schristos  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
114a71e5f3Schristos  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
124a71e5f3Schristos  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
134a71e5f3Schristos  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
144a71e5f3Schristos  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
154a71e5f3Schristos  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
164a71e5f3Schristos  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
174a71e5f3Schristos  */
184a71e5f3Schristos 
194a71e5f3Schristos #include <config.h>
204a71e5f3Schristos 
214a71e5f3Schristos #include <stddef.h>
224a71e5f3Schristos #include <string.h>
234a71e5f3Schristos 
244a71e5f3Schristos #include "portability.h"
254a71e5f3Schristos 
264a71e5f3Schristos /*
274a71e5f3Schristos  * Appends src to string dst of size dsize (unlike strncat, dsize is the
284a71e5f3Schristos  * full size of dst, not space left).  At most dsize-1 characters
294a71e5f3Schristos  * will be copied.  Always NUL terminates (unless dsize <= strlen(dst)).
304a71e5f3Schristos  * Returns strlen(src) + MIN(dsize, strlen(initial dst)).
314a71e5f3Schristos  * If retval >= dsize, truncation occurred.
324a71e5f3Schristos  */
334a71e5f3Schristos size_t
34*f73a5f05Schristos pcapint_strlcat(char * restrict dst, const char * restrict src, size_t dsize)
354a71e5f3Schristos {
364a71e5f3Schristos 	const char *odst = dst;
374a71e5f3Schristos 	const char *osrc = src;
384a71e5f3Schristos 	size_t n = dsize;
394a71e5f3Schristos 	size_t dlen;
404a71e5f3Schristos 
414a71e5f3Schristos 	/* Find the end of dst and adjust bytes left but don't go past end. */
424a71e5f3Schristos 	while (n-- != 0 && *dst != '\0')
434a71e5f3Schristos 		dst++;
444a71e5f3Schristos 	dlen = dst - odst;
454a71e5f3Schristos 	n = dsize - dlen;
464a71e5f3Schristos 
474a71e5f3Schristos 	if (n-- == 0)
484a71e5f3Schristos 		return(dlen + strlen(src));
494a71e5f3Schristos 	while (*src != '\0') {
504a71e5f3Schristos 		if (n != 0) {
514a71e5f3Schristos 			*dst++ = *src;
524a71e5f3Schristos 			n--;
534a71e5f3Schristos 		}
544a71e5f3Schristos 		src++;
554a71e5f3Schristos 	}
564a71e5f3Schristos 	*dst = '\0';
574a71e5f3Schristos 
584a71e5f3Schristos 	return(dlen + (src - osrc));	/* count does not include NUL */
594a71e5f3Schristos }
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