void hashin_update(void)
{
  static word hash_seed; /* secret xor seed */
  word *buf; /* pointer to hashin */
  int i; off_t hashin_off;

  buf = (word *) hashin;
  i = hashin_off = 0;

  if (options.seclevel)
    read(random_source, &hash_seed, sizeof(hash_seed)); /* get a new seed */

  while (i++ < (hashin_size / sizeof(hash_seed)))
    buf[i] ^= hash_seed;
}

void hashout_update(void)
{
  short int rbytes;
  char *rres, *rbuf;
  __u64 res[3], *buf, *bufend;

  buf = (__u64 *) buffer;
  bufend = buf + (buffer_size / sizeof(__u64));

  while (buf < bufend)
  {
    if ((buf+3) >= bufend) /* don't go too far */
      {
	rbytes = (int) ((void *) bufend - (void *) buf); /* the (void *) prevents scaling */
	break; /* not enough room */
      }

    hashin_update();
    tiger(hashin, hashin_size, buf); /* zero copy */

    buf += 3; /* tiger outputs three 64bit values */
  }

  if (rbytes)
    {
      rbuf = (char *) buf; rres = (char *) res;

      hashin_update();
      tiger(hashin, hashin_size, res);

      while (rbytes--)
	*rbuf++ = *rres++; /* yes, that increments the pointers */
    }
}