stdlib/strlcpy.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 #include "compiler.h"
  18
  19 /*
  20  * Copy src to string dst of size siz.  At most siz-1 characters
  21  * will be copied.  Always NUL terminates (unless siz == 0).
  22  * Returns strlen(src); if retval >= siz, truncation occurred.
  23  */
  24 #ifndef HAVE_STRLCPY
  25
  26 size_t strlcpy(char *dst, const char *src, size_t siz)
  27 {
  28     char *d = dst;
  29     const char *s = src;
  30     size_t n = siz;
  31
  32     /* Copy as many bytes as will fit */
  33     if (n != 0) {
  34         while (--n != 0) {
  35             if ((*d++ = *s++) == '\0')
  36                 break;
  37         }
  38     }
  39
  40     /* Not enough room in dst, add NUL and traverse rest of src */
  41     if (n == 0) {
  42         if (siz != 0)
  43             *d = '\0';          /* NUL-terminate dst */
  44         while (*s++)
  45             ;
  46     }
  47
  48     return(s - src - 1);        /* count does not include NUL */
  49 }
  50
  51 #endif