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strlcat.c revision 1.3.34.1 
      1 /*	$NetBSD: strlcat.c,v 1.3.34.1 2014/05/22 11:26:30 yamt Exp $	*/
      2 /*	$OpenBSD: strlcat.c,v 1.10 2003/04/12 21:56:39 millert Exp $	*/
      3 
      4 /*
      5  * Copyright (c) 1998 Todd C. Miller <Todd.Miller (at) courtesan.com>
      6  *
      7  * Permission to use, copy, modify, and distribute this software for any
      8  * purpose with or without fee is hereby granted, provided that the above
      9  * copyright notice and this permission notice appear in all copies.
     10  *
     11  * THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
     12  * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
     13  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
     14  * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
     16  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
     17  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     18  */
     19 
     20 #if !defined(_KERNEL) && !defined(_STANDALONE)
     21 #if HAVE_NBTOOL_CONFIG_H
     22 #include "nbtool_config.h"
     23 #endif
     24 
     25 #include <sys/cdefs.h>
     26 #if defined(LIBC_SCCS) && !defined(lint)
     27 __RCSID("$NetBSD: strlcat.c,v 1.3.34.1 2014/05/22 11:26:30 yamt Exp $");
     28 #endif /* LIBC_SCCS and not lint */
     29 
     30 #ifdef _LIBC
     31 #include "namespace.h"
     32 #endif
     33 #include <sys/types.h>
     34 #include <assert.h>
     35 #include <string.h>
     36 
     37 #ifdef _LIBC
     38 # ifdef __weak_alias
     39 __weak_alias(strlcat, _strlcat)
     40 # endif
     41 #endif
     42 
     43 #else
     44 #include <lib/libkern/libkern.h>
     45 #endif /* !_KERNEL && !_STANDALONE */
     46 
     47 #if !HAVE_STRLCAT
     48 /*
     49  * Appends src to string dst of size siz (unlike strncat, siz is the
     50  * full size of dst, not space left).  At most siz-1 characters
     51  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
     52  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
     53  * If retval >= siz, truncation occurred.
     54  */
     55 size_t
     56 strlcat(char *dst, const char *src, size_t siz)
     57 {
     58 #if 1
     59 	char *d = dst;
     60 	const char *s = src;
     61 	size_t n = siz;
     62 	size_t dlen;
     63 
     64 	_DIAGASSERT(dst != NULL);
     65 	_DIAGASSERT(src != NULL);
     66 
     67 	/* Find the end of dst and adjust bytes left but don't go past end */
     68 	while (n-- != 0 && *d != '\0')
     69 		d++;
     70 	dlen = d - dst;
     71 	n = siz - dlen;
     72 
     73 	if (n == 0)
     74 		return(dlen + strlen(s));
     75 	while (*s != '\0') {
     76 		if (n != 1) {
     77 			*d++ = *s;
     78 			n--;
     79 		}
     80 		s++;
     81 	}
     82 	*d = '\0';
     83 
     84 	return(dlen + (s - src));	/* count does not include NUL */
     85 #else
     86 	_DIAGASSERT(dst != NULL);
     87 	_DIAGASSERT(src != NULL);
     88 
     89 	/*
     90 	 * Find length of string in dst (maxing out at siz).
     91 	 */
     92 	size_t dlen = strnlen(dst, siz);
     93 
     94 	/*
     95 	 * Copy src into any remaining space in dst (truncating if needed).
     96 	 * Note strlcpy(dst, src, 0) returns strlen(src).
     97 	 */
     98 	return dlen + strlcpy(dst + dlen, src, siz - dlen);
     99 #endif
    100 }
    101 #endif
    102