my_copy() can cause infinite loop

   while ((Count=my_read(from_file, buff, sizeof(buff), MyFlags)) != 0)        

    {                                                                           

        if (Count == (uint) -1 ||                                             

            my_write(to_file,buff,Count,MYF(MyFlags | MY_NABP)))                

        goto err;                                                               

    }