src/init.cpp

   1 /* Copyright (C) 2007-2012 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 <cassert>
  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':
  54                 c = BLACK;
  55                 t = PAWN;
  56                 break;
  57             case 'n':
  58                 c = BLACK;
  59                 t = KNIGHT;
  60                 break;
  61             case 'b':
  62                 c = BLACK;
  63                 t = BISHOP;
  64                 break;
  65             case 'r':
  66                 c = BLACK;
  67                 t = ROOK;
  68                 break;
  69             case 'q':
  70                 c = BLACK;
  71                 t = QUEEN;
  72                 break;
  73             case 'k':
  74                 c = BLACK;
  75                 t = KING;
  76                 break;
  77             case 'P':
  78                 c = WHITE;
  79                 t = PAWN;
  80                 break;
  81             case 'N':
  82                 c = WHITE;
  83                 t = KNIGHT;
  84                 break;
  85             case 'B':
  86                 c = WHITE;
  87                 t = BISHOP;
  88                 break;
  89             case 'R':
  90                 c = WHITE;
  91                 t = ROOK;
  92                 break;
  93             case 'Q':
  94                 c = WHITE;
  95                 t = QUEEN;
  96                 break;
  97             case 'K':
  98                 c = WHITE;
  99                 t = KING;
 100                 break;
 101             default:
 102                 assert(false);
 103             }
 104             add_piece(c, t, s);
 105             s = Square(s + RIGHT); // Next square
 106         }
 107     }
 108     assert(s == Square(H1 + RIGHT));
 109
 110     // Set the side to move
 111     char side;
 112     iss >> side;
 113     assert(current_position().side() == WHITE);
 114     switch(side) {
 115     case 'w':
 116         break;
 117     case 'b':
 118         current_position().change_side();
 119         break;
 120     default:
 121         assert(false);
 122         break;
 123     }
 124
 125     std::string castling;
 126     iss >> castling;
 127     for (auto it = castling.begin(); it != castling.end(); ++it) {
 128         switch(*it) {
 129         case 'K':
 130             current_position().set_castle_right(WHITE, KING);
 131             break;
 132         case 'Q':
 133             current_position().set_castle_right(WHITE, QUEEN);
 134             break;
 135         case 'k':
 136             current_position().set_castle_right(BLACK, KING);
 137             break;
 138         case 'q':
 139             current_position().set_castle_right(BLACK, QUEEN);
 140             break;
 141         case '-':
 142             break;
 143         }
 144     }
 145
 146     std::string ep;
 147     iss >> ep;
 148     if (ep != "-") {
 149         char file = ep.at(0);
 150         char rank = ep.at(1);
 151         s = Square((rank - '1') * 16 + file - 'a');
 152         assert(!board.is_out(s));
 153         current_position().set_en_passant(s);
 154     }
 155
 156     int halfmove = 0;
 157     iss >> halfmove;
 158     current_position().set_halfmove(halfmove);
 159
 160     int fullmove = 1;
 161     iss >> fullmove;
 162     int ply = 2 * (fullmove - 1);
 163     if (current_position().side() == BLACK) {
 164         ++ply;
 165     }
 166     tree.set_ply(ply);
 167 }