src/init.cpp

   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 #include <assert.h>
  18 #include <iostream>
  19 #include <sstream>
  20 #include <string>
  21
  22 #include "game.h"
  23
  24 /*
  25  * Initialise the game according to a FEN record.
  26  * For example the starting position in chess is:
  27  * rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
  28  */
  29 void Game::init(std::string fen)
  30 {
  31     assert(fen.length() > 0);
  32     std::istringstream iss(fen);
  33
  34     // Initialize objects
  35     board = Board();
  36     pieces = Pieces();
  37     tree = Tree();
  38
  39     // Parse board positions
  40     Square s = A8;
  41     std::string positions;
  42     iss >> positions;
  43     for (auto it = positions.begin(); it != positions.end(); ++it) {
  44         char sq = *it;
  45         if (sq == '/') {
  46             s = Square(s + DOWN + 8 * LEFT); // New rank
  47         } else if ('1' <= sq && sq <= '8') { // Empty squares
  48             s = Square(s + sq - '1' + 1); // Next square
  49         } else { // Non empty square
  50             Color c = WHITE;
  51             PieceType t = EMPTY;
  52             switch (sq) {
  53                 case 'p': c = BLACK, t = PAWN; break;
  54                 case 'n': c = BLACK, t = KNIGHT; break;
  55                 case 'b': c = BLACK, t = BISHOP; break;
  56                 case 'r': c = BLACK, t = ROOK; break;
  57                 case 'q': c = BLACK, t = QUEEN; break;
  58                 case 'k': c = BLACK, t = KING; break;
  59                 case 'P': c = WHITE, t = PAWN; break;
  60                 case 'N': c = WHITE, t = KNIGHT; break;
  61                 case 'B': c = WHITE, t = BISHOP; break;
  62                 case 'R': c = WHITE, t = ROOK; break;
  63                 case 'Q': c = WHITE, t = QUEEN; break;
  64                 case 'K': c = WHITE, t = KING; break;
  65                 default: assert(false);
  66             }
  67             add_piece(c, t, s);
  68             s = Square(s + RIGHT); // Next square
  69         }
  70     }
  71     assert(s == Square(H1 + RIGHT));
  72
  73     // Set the side to move
  74     char side;
  75     iss >> side;
  76     assert(current_position().turn_color() == WHITE);
  77     switch(side) {
  78         case 'w': break;
  79         case 'b': current_position().change_side(); break;
  80         default: assert(!"FEN: no side to move!"); break;
  81     }
  82
  83     std::string castling;
  84     iss >> castling;
  85     for (auto it = castling.begin(); it != castling.end(); ++it) {
  86         switch(*it) {
  87             case '-': break;
  88             case 'K': current_position().set_castle_right(WHITE, KING); break;
  89             case 'Q': current_position().set_castle_right(WHITE, QUEEN); break;
  90             case 'k': current_position().set_castle_right(BLACK, KING); break;
  91             case 'q': current_position().set_castle_right(BLACK, QUEEN); break;
  92         }
  93     }
  94
  95     std::string ep;
  96     iss >> ep;
  97     if (ep != "-") {
  98         char file = ep.at(0);
  99         char rank = ep.at(1);
 100         s = Square((rank - '1') * 16 + file - 'a');
 101         assert(!board.is_out(s));
 102         current_position().set_en_passant(s);
 103     }
 104
 105     int halfmove = 0;
 106     iss >> halfmove;
 107     current_position().set_halfmove(halfmove);
 108
 109     int fullmove = 1;
 110     iss >> fullmove;
 111     int ply = 2 * (fullmove - 1);
 112     if (current_position().turn_color() == BLACK) ++ply;
 113     tree.set_ply(ply);
 114 }