shotgun/lib/strlcat.c

   1 /*
   2  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef HAVE_STRLCAT
  18
  19 #include <sys/types.h>
  20 #include <string.h>
  21
  22 /*
  23  * Appends src to string dst of size siz (unlike strncat, siz is the
  24  * full size of dst, not space left).  At most siz-1 characters
  25  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
  26  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
  27  * If retval >= siz, truncation occurred.
  28  */
  29 size_t
  30 strlcat (char *dst, const char *src, size_t siz)
  31 {
  32         register char *d = dst;
  33         register const char *s = src;
  34         register size_t n = siz;
  35         size_t dlen;
  36
  37         /* Find the end of dst and adjust bytes left but don't go past end */
  38         while (n-- && *d)
  39                 d++;
  40
  41         dlen = d - dst;
  42         n = siz - dlen;
  43
  44         if (!n)
  45                 return (dlen + strlen (s));
  46
  47         while (*s) {
  48                 if (n != 1) {
  49                         *d++ = *s;
  50                         n--;
  51                 }
  52
  53                 s++;
  54         }
  55
  56         *d = '\0';
  57
  58         return (dlen + (s - src));      /* count does not include NUL */
  59 }
  60
  61 #endif