2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
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/>.
29 #include "ucioption.h"
35 // FEN string of the initial position, normal chess
36 const char* StartFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
38 // Keep track of position keys along the setup moves (from start position to the
39 // position just before to start searching). This is needed by draw detection
40 // where, due to 50 moves rule, we need to check at most 100 plies back.
41 StateInfo StateRingBuf[102], *SetupState = StateRingBuf;
43 void set_option(istringstream& up);
44 void set_position(Position& pos, istringstream& up);
45 void go(Position& pos, istringstream& up);
46 void perft(Position& pos, istringstream& up);
50 /// Wait for a command from the user, parse this text string as an UCI command,
51 /// and call the appropriate functions. Also intercepts EOF from stdin to ensure
52 /// that we exit gracefully if the GUI dies unexpectedly. In addition to the UCI
53 /// commands, the function also supports a few debug commands.
57 Position pos(StartFEN, false, 0); // The root position
60 while (token != "quit")
62 if (!getline(cin, cmd)) // Block here waiting for input
65 istringstream is(cmd);
67 is >> skipws >> token;
69 if (token == "quit" || token == "stop")
70 Threads.stop_thinking();
72 else if (token == "ponderhit")
74 // The opponent has played the expected move. GUI sends "ponderhit" if
75 // we were told to ponder on the same move the opponent has played. We
76 // should continue searching but switching from pondering to normal search.
77 Search::Limits.ponder = false;
79 if (Search::Signals.stopOnPonderhit)
80 Threads.stop_thinking();
83 else if (token == "go")
86 else if (token == "ucinewgame")
87 pos.from_fen(StartFEN, false);
89 else if (token == "isready")
90 cout << "readyok" << endl;
92 else if (token == "position")
93 set_position(pos, is);
95 else if (token == "setoption")
98 else if (token == "perft")
101 else if (token == "d")
104 else if (token == "flip")
107 else if (token == "eval")
108 cout << Eval::trace(pos) << endl;
110 else if (token == "key")
111 cout << "key: " << hex << pos.key()
112 << "\nmaterial key: " << pos.material_key()
113 << "\npawn key: " << pos.pawn_key() << endl;
115 else if (token == "uci")
116 cout << "id name " << engine_info(true)
118 << "\nuciok" << endl;
120 cout << "Unknown command: " << cmd << endl;
127 // set_position() is called when engine receives the "position" UCI
128 // command. The function sets up the position described in the given
129 // fen string ("fen") or the starting position ("startpos") and then
130 // makes the moves given in the following move list ("moves").
132 void set_position(Position& pos, istringstream& is) {
139 if (token == "startpos")
142 is >> token; // Consume "moves" token if any
144 else if (token == "fen")
145 while (is >> token && token != "moves")
150 pos.from_fen(fen, Options["UCI_Chess960"]);
152 // Parse move list (if any)
153 while (is >> token && (m = move_from_uci(pos, token)) != MOVE_NONE)
155 pos.do_move(m, *SetupState);
157 // Increment pointer to StateRingBuf circular buffer
158 if (++SetupState - StateRingBuf >= 102)
159 SetupState = StateRingBuf;
164 // set_option() is called when engine receives the "setoption" UCI command. The
165 // function updates the UCI option ("name") to the given value ("value").
167 void set_option(istringstream& is) {
169 string token, name, value;
171 is >> token; // Consume "name" token
173 // Read option name (can contain spaces)
174 while (is >> token && token != "value")
175 name += string(" ", !name.empty()) + token;
177 // Read option value (can contain spaces)
179 value += string(" ", !value.empty()) + token;
181 if (!Options.count(name))
182 cout << "No such option: " << name << endl;
184 else if (value.empty()) // UCI buttons don't have a value
185 Options[name] = true;
188 Options[name] = value;
192 // go() is called when engine receives the "go" UCI command. The function sets
193 // the thinking time and other parameters from the input string, and then starts
194 // the main searching thread.
196 void go(Position& pos, istringstream& is) {
199 Search::LimitsType limits;
200 std::set<Move> searchMoves;
201 int time[] = { 0, 0 }, inc[] = { 0, 0 };
205 if (token == "infinite")
206 limits.infinite = true;
207 else if (token == "ponder")
208 limits.ponder = true;
209 else if (token == "wtime")
211 else if (token == "btime")
213 else if (token == "winc")
215 else if (token == "binc")
217 else if (token == "movestogo")
218 is >> limits.movesToGo;
219 else if (token == "depth")
220 is >> limits.maxDepth;
221 else if (token == "nodes")
222 is >> limits.maxNodes;
223 else if (token == "movetime")
224 is >> limits.maxTime;
225 else if (token == "searchmoves")
227 searchMoves.insert(move_from_uci(pos, token));
230 limits.time = time[pos.side_to_move()];
231 limits.increment = inc[pos.side_to_move()];
233 Threads.start_thinking(pos, limits, searchMoves, true);
237 // perft() is called when engine receives the "perft" command. The function
238 // calls perft() with the required search depth then prints counted leaf nodes
241 void perft(Position& pos, istringstream& is) {
248 Time time = Time::current_time();
250 int64_t n = Search::perft(pos, depth * ONE_PLY);
252 int e = time.elapsed();
254 std::cout << "\nNodes " << n
255 << "\nTime (ms) " << e
256 << "\nNodes/second " << int(n / (e / 1000.0)) << std::endl;