rosapps/applications/net/ncftp/Strn/Strncpy.c

   1 #include <sys/types.h>
   2 #include <string.h>
   3 #include "Strn.h"
   4
   5
   6 /*
   7  * Copy src to dst, truncating or null-padding to always copy n-1 bytes.
   8  * Return dst.
   9  */
  10 char *
  11 Strncpy(char *const dst, const char *const src, const size_t n)
  12 {
  13         register char *d;
  14         register const char *s;
  15         register size_t i;
  16
  17         d = dst;
  18         *d = 0;
  19         if (n != 0) {
  20                 s = src;
  21                 /* If they specified a maximum of n characters, use n - 1 chars to
  22                  * hold the copy, and the last character in the array as a NUL.
  23                  * This is the difference between the regular strncpy routine.
  24                  * strncpy doesn't guarantee that your new string will have a
  25                  * NUL terminator, but this routine does.
  26                  */
  27                 for (i=1; i<n; i++) {
  28                         if ((*d++ = *s++) == 0) {
  29 #if (STRN_ZERO_PAD == 1)
  30                                 /* Pad with zeros. */
  31                                 for (; i<n; i++)
  32                                         *d++ = 0;
  33 #endif  /* STRN_ZERO_PAD */
  34                                 return dst;
  35                         }
  36                 }
  37                 /* If we get here, then we have a full string, with n - 1 characters,
  38                  * so now we NUL terminate it and go home.
  39                  */
  40                 *d = 0;
  41         }
  42         return (dst);
  43 }       /* Strncpy */
  44
  45 /* eof Strn.c */