src/zobrist.h

   1 /* Copyright (C) 2007-2011 Vincent Ollivier
   2  *
   3  * Purple Haze is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 3 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * Purple Haze is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #ifndef ZOBRIST_H
  18 #define ZOBRIST_H
  19
  20 #include <iostream>
  21 #include <random>
  22
  23 #include "common.h"
  24
  25 typedef uint64_t Hash;
  26
  27 class Zobrist
  28 {
  29     private:
  30         Hash gen_hash();
  31         Hash pieces_positions[2][7][BOARD_SIZE];
  32         Hash side_to_move;
  33         Hash castle_rights[4];
  34         Hash en_passants[BOARD_SIZE];
  35         std::mt19937_64 generator;
  36
  37     public:
  38         Zobrist();
  39         void change_side(Hash& h) {
  40             h ^= side_to_move;
  41         };
  42         void update_piece(Hash& h, Color c, PieceType t, Square s) {
  43             h ^= pieces_positions[c][t][s];
  44         };
  45         void update_castle_right(Hash& h, Color c, PieceType t) {
  46             h ^= castle_rights[2 * c + t - QUEEN];
  47         };
  48         void update_en_passant(Hash& h, Square s) {
  49             h ^= en_passants[s];
  50         };
  51         friend std::ostream& operator<<(std::ostream& out, const Zobrist& zobrist);
  52 };
  53
  54 #endif /* !ZOBRIST_H */