if(file_size<THRESHOLD) {
download_all();
} else {
digest = "";
digest += file_length;
digest += download(0, 100);
digest += download(file_length - 100, file_length);
digest += download(file_length/2 - 50, file_length + 50);
if (check_hash(digest)) {
download_cached_file(digest);
} else {
download_all();
}
}
