reactos/apps/utils/net/ncftp/Strn/Strncat.c

   1 #include <sys/types.h>
   2 #include <string.h>
   3 #include "Strn.h"
   4
   5 /*
   6  * Concatenate src on the end of dst.  The resulting string will have at most
   7  * n-1 characters, not counting the NUL terminator which is always appended
   8  * unlike strncat.  The other big difference is that strncpy uses n as the
   9  * max number of characters _appended_, while this routine uses n to limit
  10  * the overall length of dst.
  11  */
  12 char *
  13 Strncat(char *const dst, const char *const src, const size_t n)
  14 {
  15         register size_t i;
  16         register char *d;
  17         register const char *s;
  18
  19         if (n != 0 && ((i = strlen(dst)) < (n - 1))) {
  20                 d = dst + i;
  21                 s = src;
  22                 /* If they specified a maximum of n characters, use n - 1 chars to
  23                  * hold the copy, and the last character in the array as a NUL.
  24                  * This is the difference between the regular strncpy routine.
  25                  * strncpy doesn't guarantee that your new string will have a
  26                  * NUL terminator, but this routine does.
  27                  */
  28                 for (++i; i<n; i++) {
  29                         if ((*d++ = *s++) == 0) {
  30 #if (STRN_ZERO_PAD == 1)
  31                                 /* Pad with zeros. */
  32                                 for (; i<n; i++)
  33                                         *d++ = 0;
  34 #endif  /* STRN_ZERO_PAD */
  35                                 return dst;
  36                         }
  37                 }
  38                 /* If we get here, then we have a full string, with n - 1 characters,
  39                  * so now we NUL terminate it and go home.
  40                  */
  41                 *d = 0;
  42         }
  43         return (dst);
  44 }       /* Strncat */