int file_is_half_open(Color c, File f) const;
int has_open_file_to_left(Color c, File f) const;
int has_open_file_to_right(Color c, File f) const;
int get_king_shelter(const Position& pos, Color c, Square ksq);
private:
int file_is_half_open(Color c, File f) const;
int has_open_file_to_left(Color c, File f) const;
int has_open_file_to_right(Color c, File f) const;
int get_king_shelter(const Position& pos, Color c, Square ksq);
private: