+int nb_interested_peers(peer_t peer);
+int is_interested(peer_t peer, connection_t remote_peer);
+int is_interested_and_free(peer_t peer, connection_t remote_peer);
+int in_current_pieces(peer_t peer, int piece);
+int partially_downloaded_piece(peer_t peer, connection_t remote_peer);
+
+void request_new_piece_to_peer(peer_t peer, connection_t remote_peer);
+void send_request_to_peer(peer_t peer, connection_t remote_peer, int piece);
+void remove_current_piece(peer_t peer, connection_t remote_peer, int current_piece);
+
+void update_active_peers_set(peer_t peer, connection_t remote_peer);
+int select_piece_to_download(peer_t peer, connection_t remote_peer);