2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
5 Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
7 Stockfish is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 Stockfish is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
34 #include "syzygy/tbprobe.h"
38 extern void benchmark(const Position& pos, istream& is);
42 // FEN string of the initial position, normal chess
43 const char* StartFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
46 // position() is called when engine receives the "position" UCI command.
47 // The function sets up the position described in the given FEN string ("fen")
48 // or the starting position ("startpos") and then makes the moves given in the
49 // following move list ("moves").
51 void position(Position& pos, istringstream& is, StateListPtr& states) {
58 if (token == "startpos")
61 is >> token; // Consume "moves" token if any
63 else if (token == "fen")
64 while (is >> token && token != "moves")
69 states = StateListPtr(new std::deque<StateInfo>(1)); // Drop old and create a new one
70 pos.set(fen, Options["UCI_Chess960"], &states->back(), Threads.main());
72 // Parse move list (if any)
73 while (is >> token && (m = UCI::to_move(pos, token)) != MOVE_NONE)
75 states->emplace_back();
76 pos.do_move(m, states->back());
81 // setoption() is called when engine receives the "setoption" UCI command. The
82 // function updates the UCI option ("name") to the given value ("value").
84 void setoption(istringstream& is) {
86 string token, name, value;
88 is >> token; // Consume "name" token
90 // Read option name (can contain spaces)
91 while (is >> token && token != "value")
92 name += string(" ", name.empty() ? 0 : 1) + token;
94 // Read option value (can contain spaces)
96 value += string(" ", value.empty() ? 0 : 1) + token;
98 if (Options.count(name))
99 Options[name] = value;
101 sync_cout << "No such option: " << name << sync_endl;
105 // go() is called when engine receives the "go" UCI command. The function sets
106 // the thinking time and other parameters from the input string, then starts
109 void go(Position& pos, istringstream& is, StateListPtr& states) {
111 Search::LimitsType limits;
113 bool ponderMode = false;
115 limits.startTime = now(); // As early as possible!
118 if (token == "searchmoves")
120 limits.searchmoves.push_back(UCI::to_move(pos, token));
122 else if (token == "wtime") is >> limits.time[WHITE];
123 else if (token == "btime") is >> limits.time[BLACK];
124 else if (token == "winc") is >> limits.inc[WHITE];
125 else if (token == "binc") is >> limits.inc[BLACK];
126 else if (token == "movestogo") is >> limits.movestogo;
127 else if (token == "depth") is >> limits.depth;
128 else if (token == "nodes") is >> limits.nodes;
129 else if (token == "movetime") is >> limits.movetime;
130 else if (token == "mate") is >> limits.mate;
131 else if (token == "infinite") limits.infinite = 1;
132 else if (token == "ponder") ponderMode = true;
134 Threads.start_thinking(pos, states, limits, ponderMode);
140 /// UCI::loop() waits for a command from stdin, parses it and calls the appropriate
141 /// function. Also intercepts EOF from stdin to ensure gracefully exiting if the
142 /// GUI dies unexpectedly. When called with some command line arguments, e.g. to
143 /// run 'bench', once the command is executed the function returns immediately.
144 /// In addition to the UCI ones, also some additional debug commands are supported.
146 void UCI::loop(int argc, char* argv[]) {
150 StateListPtr states(new std::deque<StateInfo>(1));
151 auto uiThread = std::make_shared<Thread>(0);
153 pos.set(StartFEN, false, &states->back(), uiThread.get());
155 for (int i = 1; i < argc; ++i)
156 cmd += std::string(argv[i]) + " ";
159 if (argc == 1 && !getline(cin, cmd)) // Block here waiting for input or EOF
162 istringstream is(cmd);
164 token.clear(); // Avoid a stale if getline() returns empty or blank line
165 is >> skipws >> token;
167 // The GUI sends 'ponderhit' to tell us the user has played the expected move.
168 // So 'ponderhit' will be sent if we were told to ponder on the same move the
169 // user has played. We should continue searching but switch from pondering to
170 // normal search. In case Threads.stopOnPonderhit is set we are waiting for
171 // 'ponderhit' to stop the search, for instance if max search depth is reached.
174 || (token == "ponderhit" && Threads.stopOnPonderhit))
177 else if (token == "ponderhit")
178 Threads.ponder = false; // Switch to normal search
180 else if (token == "uci")
181 sync_cout << "id name " << engine_info(true)
183 << "\nuciok" << sync_endl;
185 else if (token == "setoption") setoption(is);
186 else if (token == "go") go(pos, is, states);
187 else if (token == "position") position(pos, is, states);
188 else if (token == "ucinewgame") Search::clear();
189 else if (token == "isready") sync_cout << "readyok" << sync_endl;
191 // Additional custom non-UCI commands, mainly for debugging
192 else if (token == "flip") pos.flip();
193 else if (token == "bench") benchmark(pos, is);
194 else if (token == "d") sync_cout << pos << sync_endl;
195 else if (token == "eval") sync_cout << Eval::trace(pos) << sync_endl;
196 else if (token == "perft")
202 ss << Options["Hash"] << " " << Options["Threads"]
203 << " " << depth << " current perft";
208 sync_cout << "Unknown command: " << cmd << sync_endl;
210 } while (token != "quit" && argc == 1); // Command line args are one-shot
214 /// UCI::value() converts a Value to a string suitable for use with the UCI
215 /// protocol specification:
217 /// cp <x> The score from the engine's point of view in centipawns.
218 /// mate <y> Mate in y moves, not plies. If the engine is getting mated
219 /// use negative values for y.
221 string UCI::value(Value v) {
223 assert(-VALUE_INFINITE < v && v < VALUE_INFINITE);
227 if (abs(v) < VALUE_MATE - MAX_PLY)
228 ss << "cp " << v * 100 / PawnValueEg;
230 ss << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
236 /// UCI::square() converts a Square to a string in algebraic notation (g1, a7, etc.)
238 std::string UCI::square(Square s) {
239 return std::string{ char('a' + file_of(s)), char('1' + rank_of(s)) };
243 /// UCI::move() converts a Move to a string in coordinate notation (g1f3, a7a8q).
244 /// The only special case is castling, where we print in the e1g1 notation in
245 /// normal chess mode, and in e1h1 notation in chess960 mode. Internally all
246 /// castling moves are always encoded as 'king captures rook'.
248 string UCI::move(Move m, bool chess960) {
250 Square from = from_sq(m);
251 Square to = to_sq(m);
259 if (type_of(m) == CASTLING && !chess960)
260 to = make_square(to > from ? FILE_G : FILE_C, rank_of(from));
262 string move = UCI::square(from) + UCI::square(to);
264 if (type_of(m) == PROMOTION)
265 move += " pnbrqk"[promotion_type(m)];
271 /// UCI::to_move() converts a string representing a move in coordinate notation
272 /// (g1f3, a7a8q) to the corresponding legal Move, if any.
274 Move UCI::to_move(const Position& pos, string& str) {
276 if (str.length() == 5) // Junior could send promotion piece in uppercase
277 str[4] = char(tolower(str[4]));
279 for (const auto& m : MoveList<LEGAL>(pos))
280 if (str == UCI::move(m, pos.is_chess960()))