strlcpy.h

   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 /*
  18  * Copy src to string dst of size siz.  At most siz-1 characters
  19  * will be copied.  Always NUL terminates (unless siz == 0).
  20  * Returns strlen(src); if retval >= siz, truncation occurred.
  21  */
  22 inline size_t strlcpy(char *dst, const char *src, size_t siz)
  23 {
  24     char *d = dst;
  25     const char *s = src;
  26     size_t n = siz;
  27
  28     /* Copy as many bytes as will fit */
  29     if (n != 0)
  30     {
  31         while (--n != 0)
  32         {
  33             if ((*d++ = *s++) == '\0')
  34                 break;
  35         }
  36     }
  37
  38     /* Not enough room in dst, add NUL and traverse rest of src */
  39     if (n == 0)
  40     {
  41         if (siz != 0)
  42             *d = '\0';  /* NUL-terminate dst */
  43         while (*s++)
  44             ;
  45     }
  46
  47     return(s - src - 1); /* count does not include NUL */
  48 }
  49
  50 /*
  51  * Appends src to string dst of size siz (unlike strncat, siz is the
  52  * full size of dst, not space left).  At most siz-1 characters
  53  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
  54  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
  55  * If retval >= siz, truncation occurred.
  56  */
  57 inline size_t 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     /* Find the end of dst and adjust bytes left but don't go past end */
  65     while (n-- != 0 && *d != '\0')
  66         d++;
  67     dlen = d - dst;
  68     n = siz - dlen;
  69
  70     if (n == 0)
  71         return(dlen + strlen(s));
  72     while (*s != '\0')
  73     {
  74         if (n != 1)
  75         {
  76             *d++ = *s;
  77             n--;
  78         }
  79         s++;
  80     }
  81     *d = '\0';
  82
  83     return(dlen + (s - src)); /* count does not include NUL */
  84 }