FastBoard.h

#ifndef FASTBOARD_H_INCLUDED
#define FASTBOARD_H_INCLUDED

#include "config.h"

#include <array>
#include <queue>
#include <string>
#include <utility>
#include <vector>
#include <cstring>
#include <nmmintrin.h>
#include <assert.h>

#include "pattern3x3.h"
#include "distance.h"

class FastBoard {
    friend class FastState;
public:
    /*
        neighbor counts are up to 4, so 3 bits is ok,
        but a power of 2 makes things a bit faster
    */
    static constexpr int NBR_SHIFT = 4;
    static constexpr int NBR_MASK = (1 << NBR_SHIFT) - 1;

    /*
        highest existing square
    */
    static constexpr int MAXSQ = ((BOARD_SIZE + 2) * (BOARD_SIZE + 2));

    /*
        infinite score
    */
    static constexpr int BIG = 10000000;

    /*
        vertex of a pass
    */
    static constexpr int PASS   = -1;
    /*
        vertex of a "resign move"
    */
    static constexpr int RESIGN = -2;

    /*
        possible contents of a square
    */
    enum square_t : char {
        BLACK = 0, WHITE = 1, EMPTY = 2, INVAL = 3
    };

    /*
        move generation types
    */
    using movescore_t = std::pair<int, float>;
    using scoredmoves_t = std::vector<movescore_t>;

    int get_boardsize(void) const;
    square_t get_square(int x, int y) const;
    square_t get_square(int vertex) const ;
    int get_vertex(int i, int j) const;
    void set_square(int x, int y, square_t content);
    void set_square(int vertex, square_t content);
    std::pair<int, int> get_xy(int vertex) const;

    bool is_suicide(int i, int color) const;
    int count_pliberties(const int i) const;
    bool is_eye(const int color, const int vtx) const;

    float area_score(float komi) const;

    int get_prisoners(int side) const;
    bool black_to_move() const;
    bool white_to_move() const;
    int get_to_move() const;
    void set_to_move(int color);

    std::string move_to_text(int move) const;
    std::string move_to_text_sgf(int move) const;
    std::string get_stone_list() const;
    std::string get_string(int vertex) const;

    void reset_board(int size);
    void display_board(int lastmove = -1);

    static bool starpoint(int size, int point);
    static bool starpoint(int size, int x, int y);

protected:
    /*
        bit masks to detect eyes on neighbors
    */
    static const std::array<int,      2> s_eyemask;
    static const std::array<square_t, 4> s_cinvert; /* color inversion */

    std::array<square_t, MAXSQ>            m_square;      /* board contents */
    std::array<unsigned short, MAXSQ+1>    m_next;        /* next stone in string */
    std::array<unsigned short, MAXSQ+1>    m_parent;      /* parent node of string */
    std::array<unsigned short, MAXSQ+1>    m_libs;        /* liberties per string parent */
    std::array<unsigned short, MAXSQ+1>    m_stones;      /* stones per string parent */
    std::array<unsigned short, MAXSQ>      m_neighbours;  /* counts of neighboring stones */
    std::array<int, 4>                     m_dirs;        /* movement directions 4 way */
    std::array<int, 2>                     m_prisoners;   /* prisoners per color */
    std::array<unsigned short, MAXSQ>      m_empty;       /* empty squares */
    std::array<unsigned short, MAXSQ>      m_empty_idx;   /* indexes of square */
    int m_empty_cnt;                                      /* count of empties */

    int m_tomove;
    int m_maxsq;

    int m_boardsize;
    int m_squaresize;

    int calc_reach_color(int color) const;

    int count_neighbours(const int color, const int i) const;
    void merge_strings(const int ip, const int aip);
    void add_neighbour(const int i, const int color);
    void remove_neighbour(const int i, const int color);
    void print_columns();
};

#endif