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      1 /*  $NetBSD: strlcat.c,v 1.3 2007/06/04 18:19:27 christos 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 #include  <LibConfig.h>
     20 
     21 #if !defined(_KERNEL) && !defined(_STANDALONE)
     22 #if HAVE_NBTOOL_CONFIG_H
     23 #include "nbtool_config.h"
     24 #endif
     25 
     26 #include <sys/cdefs.h>
     27 #if defined(LIBC_SCCS) && !defined(lint)
     28 __RCSID("$NetBSD: strlcat.c,v 1.3 2007/06/04 18:19:27 christos Exp $");
     29 #endif /* LIBC_SCCS and not lint */
     30 
     31 #ifdef _LIBC
     32 #include "namespace.h"
     33 #endif
     34 #include <sys/types.h>
     35 #include <assert.h>
     36 #include <string.h>
     37 
     38 #ifdef _LIBC
     39 # ifdef __weak_alias
     40 __weak_alias(strlcat, _strlcat)
     41 # endif
     42 #endif
     43 
     44 #else
     45 #include <lib/libkern/libkern.h>
     46 #endif /* !_KERNEL && !_STANDALONE */
     47 
     48 #ifndef HAVE_STRLCAT
     49 /*
     50  * Appends src to string dst of size siz (unlike strncat, siz is the
     51  * full size of dst, not space left).  At most siz-1 characters
     52  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
     53  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
     54  * If retval >= siz, truncation occurred.
     55  */
     56 size_t
     57 strlcat(char *dst, const char *src, size_t siz)
     58 {
     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 }
     86 #endif
     87