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) {
46 Color us = pos.side_to_move();
48 if(str.length() < 4) return MOVE_NONE;
50 // Read the from and to squares:
51 from = square_from_string(str.substr(0, 2));
52 to = square_from_string(str.substr(2, 4));
54 // Find the moving piece:
55 piece = pos.piece_on(from);
57 // If the string has more than 4 characters, try to interpret the 5th
58 // character as a promotion:
59 if(type_of_piece(piece) == PAWN && str.length() >= 5) {
62 return make_promotion_move(from, to, KNIGHT);
64 return make_promotion_move(from, to, BISHOP);
66 return make_promotion_move(from, to, ROOK);
68 return make_promotion_move(from, to, QUEEN);
72 if(piece == king_of_color(us)) {
73 // Is this a castling move? A king move is assumed to be a castling
74 // move if the destination square is occupied by a friendly rook, or
75 // if the distance between the source and destination squares is more
77 if(pos.piece_on(to) == rook_of_color(us))
78 return make_castle_move(from, to);
79 else if(square_distance(from, to) > 1) {
80 // This is a castling move, but we have to translate it to the
81 // internal "king captures rook" representation.
82 SquareDelta delta = (to > from)? DELTA_E : DELTA_W;
85 relative_rank(us, s) == RANK_1 && pos.piece_on(s) != rook_of_color(us);
87 if(relative_rank(us, s) == RANK_1 && pos.piece_on(s) == rook_of_color(us))
88 return make_castle_move(from, s);
91 else if(piece == pawn_of_color(us)) {
92 // En passant move? We assume that a pawn move is an en passant move
93 // without further testing if the destination square is epSquare.
94 if(to == pos.ep_square())
95 return make_ep_move(from, to);
98 return make_move(from, to);
102 /// move_to_string() converts a move to a string in coordinate notation
103 /// (g1f3, a7a8q, etc.). The only special case is castling moves, where we
104 /// print in the e1g1 notation in normal chess mode, and in e1h1 notation in
107 const std::string move_to_string(Move move) {
110 if(move == MOVE_NONE)
112 else if(move == MOVE_NULL)
116 if(move_from(move) == SQ_E1 && move_is_short_castle(move)) {
117 str = "e1g1"; return str;
119 else if(move_from(move) == SQ_E1 && move_is_long_castle(move)) {
120 str = "e1c1"; return str;
122 if(move_from(move) == SQ_E8 && move_is_short_castle(move)) {
123 str = "e8g8"; return str;
125 else if(move_from(move) == SQ_E8 && move_is_long_castle(move)) {
126 str = "e8c8"; return str;
129 str = square_to_string(move_from(move)) + square_to_string(move_to(move));
130 if(move_promotion(move))
131 str += piece_type_to_char(move_promotion(move), false);
137 /// Overload the << operator, to make it easier to print moves.
139 std::ostream &operator << (std::ostream &os, Move m) {
140 return os << move_to_string(m);
144 /// move_is_ok(), for debugging.
146 bool move_is_ok(Move m) {
147 return square_is_ok(move_from(m)) && square_is_ok(move_to(m));