2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008 Marco Costalba
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
30 #include "ucioption.h"
37 /// move_from_string() takes a position and a string as input, and attempts to
38 /// convert the string to a move, using simple coordinate notation (g1f3,
39 /// a7a8q, etc.). In order to correctly parse en passant captures and castling
40 /// moves, we need the position. This function is not robust, and expects that
41 /// the input move is legal and correctly formatted.
43 Move move_from_string(const Position& pos, const std::string& str) {
47 Color us = pos.side_to_move();
52 // Read the from and to squares
53 from = square_from_string(str.substr(0, 2));
54 to = square_from_string(str.substr(2, 4));
56 // Find the moving piece
57 piece = pos.piece_on(from);
59 // If the string has more than 4 characters, try to interpret the 5th
60 // character as a promotion
61 if (type_of_piece(piece) == PAWN && str.length() > 4)
63 switch (tolower(str[4])) {
65 return make_promotion_move(from, to, KNIGHT);
67 return make_promotion_move(from, to, BISHOP);
69 return make_promotion_move(from, to, ROOK);
71 return make_promotion_move(from, to, QUEEN);
75 if (piece == piece_of_color_and_type(us, KING))
77 // Is this a castling move? A king move is assumed to be a castling
78 // move if the destination square is occupied by a friendly rook, or
79 // if the distance between the source and destination squares is more
81 if (pos.piece_on(to) == piece_of_color_and_type(us, ROOK))
82 return make_castle_move(from, to);
84 else if (square_distance(from, to) > 1)
86 // This is a castling move, but we have to translate it to the
87 // internal "king captures rook" representation.
88 SquareDelta delta = (to > from ? DELTA_E : DELTA_W);
89 Square s = from + delta;
90 while (relative_rank(us, s) == RANK_1 && pos.piece_on(s) != piece_of_color_and_type(us, ROOK))
93 return (relative_rank(us, s) == RANK_1 ? make_castle_move(from, s) : MOVE_NONE);
96 else if (piece == piece_of_color_and_type(us, PAWN))
98 // En passant move? We assume that a pawn move is an en passant move
99 // without further testing if the destination square is epSquare.
100 if (to == pos.ep_square())
101 return make_ep_move(from, to);
103 return make_move(from, to);
107 /// move_to_string() converts a move to a string in coordinate notation
108 /// (g1f3, a7a8q, etc.). The only special case is castling moves, where we
109 /// print in the e1g1 notation in normal chess mode, and in e1h1 notation in
112 const std::string move_to_string(Move move) {
115 Square from = move_from(move);
116 Square to = move_to(move);
118 if (move == MOVE_NONE)
120 else if (move == MOVE_NULL)
126 if (move_is_short_castle(move))
127 return (from == SQ_E1 ? "e1g1" : "e8g8");
129 if (move_is_long_castle(move))
130 return (from == SQ_E1 ? "e1c1" : "e8c8");
132 str = square_to_string(from) + square_to_string(to);
133 if (move_promotion(move))
134 str += piece_type_to_char(move_promotion(move), false);
140 /// Overload the << operator, to make it easier to print moves.
142 std::ostream &operator << (std::ostream &os, Move m) {
144 return os << move_to_string(m);
148 /// move_is_ok(), for debugging.
150 bool move_is_ok(Move m) {
152 return square_is_ok(move_from(m)) && square_is_ok(move_to(m));