int Field_bit::key_cmp(const uchar *str, uint length)
{
  if (bit_len)
  {
    int flag;
    uchar bits= get_rec_bits(bit_ptr, bit_ofs, bit_len);
    if ((flag= (int) (bits - *str)))
      return flag;
    str++;
    length--;
  }
  return memcmp(ptr, str, bytes_in_rec);
}
int Field_bit::key_cmp(const uchar *str, uint length)
{
  if (bit_len)
  {
    int flag;
    uchar bits= get_rec_bits(bit_ptr, bit_ofs, bit_len);
    if ((flag= (int) (bits - *str)))
      return flag;
    str++;
    length--;
  }
  return memcmp(ptr, str, bytes_in_rec);
}