StdLib/LibC/String/strlcat.c

   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@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