contrib/libedit/src/strlcat.c

   1 /*      $NetBSD: strlcat.c,v 1.4 2013/01/23 07:57:27 matt 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
  20 #include "config.h"
  21
  22 #if defined(LIBC_SCCS) && !defined(lint)
  23 __RCSID("$NetBSD: strlcat.c,v 1.4 2013/01/23 07:57:27 matt Exp $");
  24 #endif /* LIBC_SCCS and not lint */
  25
  26 #include <sys/types.h>
  27 #include <assert.h>
  28 #include <string.h>
  29
  30 #ifdef _LIBC
  31 # ifdef __weak_alias
  32 __weak_alias(strlcat, _strlcat)
  33 # endif
  34 #endif
  35
  36 #if !HAVE_STRLCAT
  37 /*
  38  * Appends src to string dst of size siz (unlike strncat, siz is the
  39  * full size of dst, not space left).  At most siz-1 characters
  40  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
  41  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
  42  * If retval >= siz, truncation occurred.
  43  */
  44 size_t
  45 strlcat(char *dst, const char *src, size_t siz)
  46 {
  47 #if 1
  48         char *d = dst;
  49         const char *s = src;
  50         size_t n = siz;
  51         size_t dlen;
  52
  53         _DIAGASSERT(dst != NULL);
  54         _DIAGASSERT(src != NULL);
  55
  56         /* Find the end of dst and adjust bytes left but don't go past end */
  57         while (n-- != 0 && *d != '\0')
  58                 d++;
  59         dlen = d - dst;
  60         n = siz - dlen;
  61
  62         if (n == 0)
  63                 return(dlen + strlen(s));
  64         while (*s != '\0') {
  65                 if (n != 1) {
  66                         *d++ = *s;
  67                         n--;
  68                 }
  69                 s++;
  70         }
  71         *d = '\0';
  72
  73         return(dlen + (s - src));       /* count does not include NUL */
  74 #else
  75         _DIAGASSERT(dst != NULL);
  76         _DIAGASSERT(src != NULL);
  77
  78         /*
  79          * Find length of string in dst (maxing out at siz).
  80          */
  81         size_t dlen = strnlen(dst, siz);
  82
  83         /*
  84          * Copy src into any remaining space in dst (truncating if needed).
  85          * Note strlcpy(dst, src, 0) returns strlen(src).
  86          */
  87         return dlen + strlcpy(dst + dlen, src, siz - dlen);
  88 #endif
  89 }
  90 #endif