Transform search output to engine callbacks

Part 2 of the Split UCI into UCIEngine and Engine refactor.
This creates function callbacks for search to use when an update should occur.
The benching in uci.cpp for example does this to extract the total nodes
searched.

No functional change

src/Makefile

@@ -55,15 +55,15 @@ PGOBENCH = $(WINE_PATH) ./$(EXE) bench
 SRCS = benchmark.cpp bitboard.cpp evaluate.cpp main.cpp \
 	misc.cpp movegen.cpp movepick.cpp position.cpp \
 	search.cpp thread.cpp timeman.cpp tt.cpp uci.cpp ucioption.cpp tune.cpp syzygy/tbprobe.cpp \
-	nnue/nnue_misc.cpp nnue/features/half_ka_v2_hm.cpp nnue/network.cpp engine.cpp
+	nnue/nnue_misc.cpp nnue/features/half_ka_v2_hm.cpp nnue/network.cpp engine.cpp score.cpp
 
 HEADERS = benchmark.h bitboard.h evaluate.h misc.h movegen.h movepick.h \
 		nnue/nnue_misc.h nnue/features/half_ka_v2_hm.h nnue/layers/affine_transform.h \
 		nnue/layers/affine_transform_sparse_input.h nnue/layers/clipped_relu.h nnue/layers/simd.h \
 		nnue/layers/sqr_clipped_relu.h nnue/nnue_accumulator.h nnue/nnue_architecture.h \
 		nnue/nnue_common.h nnue/nnue_feature_transformer.h position.h \
 		search.h syzygy/tbprobe.h thread.h thread_win32_osx.h timeman.h \
-		tt.h tune.h types.h uci.h ucioption.h perft.h nnue/network.h engine.h
+		tt.h tune.h types.h uci.h ucioption.h perft.h nnue/network.h engine.h score.h
 
 OBJS = $(notdir $(SRCS:.cpp=.o))
 

src/engine.cpp

@@ -18,28 +18,23 @@
 
 #include "engine.h"
 
-#include <algorithm>
-#include <cassert>
-#include <cctype>
-#include <cmath>
-#include <cstdint>
-#include <cstdlib>
 #include <deque>
 #include <memory>
-#include <optional>
-#include <sstream>
+#include <ostream>
+#include <string_view>
+#include <utility>
 #include <vector>
 
-#include "benchmark.h"
 #include "evaluate.h"
-#include "movegen.h"
+#include "misc.h"
 #include "nnue/network.h"
 #include "nnue/nnue_common.h"
 #include "perft.h"
 #include "position.h"
 #include "search.h"
 #include "syzygy/tbprobe.h"
 #include "types.h"
+#include "uci.h"
 #include "ucioption.h"
 
 namespace Stockfish {
@@ -54,7 +49,6 @@ Engine::Engine(std::string path) :
     networks(NN::Networks(
       NN::NetworkBig({EvalFileDefaultNameBig, "None", ""}, NN::EmbeddedNNUEType::BIG),
       NN::NetworkSmall({EvalFileDefaultNameSmall, "None", ""}, NN::EmbeddedNNUEType::SMALL))) {
-    Tune::init(options);
     pos.set(StartFEN, false, &states->back());
 }
 
@@ -77,10 +71,26 @@ void Engine::search_clear() {
     tt.clear(options["Threads"]);
     threads.clear();
 
-    // @TODO wont work multiple instances
+    // @TODO wont work with multiple instances
     Tablebases::init(options["SyzygyPath"]);  // Free mapped files
 }
 
+void Engine::set_on_update_no_moves(std::function<void(const Engine::InfoShort&)>&& f) {
+    updateContext.onUpdateNoMoves = std::move(f);
+}
+
+void Engine::set_on_update_full(std::function<void(const Engine::InfoFull&)>&& f) {
+    updateContext.onUpdateFull = std::move(f);
+}
+
+void Engine::set_on_iter(std::function<void(const Engine::InfoIter&)>&& f) {
+    updateContext.onIter = std::move(f);
+}
+
+void Engine::set_on_bestmove(std::function<void(std::string_view, std::string_view)>&& f) {
+    updateContext.onBestmove = std::move(f);
+}
+
 void Engine::wait_for_search_finished() { threads.main_thread()->wait_for_search_finished(); }
 
 void Engine::set_position(const std::string& fen, const std::vector<std::string>& moves) {
@@ -102,7 +112,7 @@ void Engine::set_position(const std::string& fen, const std::vector<std::string>
 
 // modifiers
 
-void Engine::resize_threads() { threads.set({options, threads, tt, networks}); }
+void Engine::resize_threads() { threads.set({options, threads, tt, networks}, updateContext); }
 
 void Engine::set_tt_size(size_t mb) {
     wait_for_search_finished();
@@ -113,7 +123,7 @@ void Engine::set_ponderhit(bool b) { threads.main_manager()->ponder = b; }
 
 // network related
 
-void Engine::verify_networks() {
+void Engine::verify_networks() const {
     networks.big.verify(options["EvalFile"]);
     networks.small.verify(options["EvalFileSmall"]);
 }
@@ -138,9 +148,7 @@ void Engine::save_network(const std::pair<std::optional<std::string>, std::strin
 
 OptionsMap& Engine::get_options() { return options; }
 
-uint64_t Engine::nodes_searched() const { return threads.nodes_searched(); }
-
-void Engine::trace_eval() {
+void Engine::trace_eval() const {
     StateListPtr trace_states(new std::deque<StateInfo>(1));
     Position     p;
     p.set(pos.fen(), options["UCI_Chess960"], &trace_states->back());

src/engine.h

@@ -19,7 +19,14 @@
 #ifndef ENGINE_H_INCLUDED
 #define ENGINE_H_INCLUDED
 
-#include "misc.h"
+#include <cstddef>
+#include <functional>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
 #include "nnue/network.h"
 #include "position.h"
 #include "search.h"
@@ -31,6 +38,10 @@ namespace Stockfish {
 
 class Engine {
    public:
+    using InfoShort = Search::InfoShort;
+    using InfoFull  = Search::InfoFull;
+    using InfoIter  = Search::InfoIteration;
+
     Engine(std::string path = "");
     ~Engine() { wait_for_search_finished(); }
 
@@ -51,19 +62,22 @@ class Engine {
     void set_ponderhit(bool);
     void search_clear();
 
+    void set_on_update_no_moves(std::function<void(const InfoShort&)>&&);
+    void set_on_update_full(std::function<void(const InfoFull&)>&&);
+    void set_on_iter(std::function<void(const InfoIter&)>&&);
+    void set_on_bestmove(std::function<void(std::string_view, std::string_view)>&&);
+
     // network related
 
-    void verify_networks();
+    void verify_networks() const;
     void load_networks();
     void load_big_network(const std::string& file);
     void load_small_network(const std::string& file);
     void save_network(const std::pair<std::optional<std::string>, std::string> files[2]);
 
     // utility functions
 
-    void trace_eval();
-    // nodes since last search clear
-    uint64_t    nodes_searched() const;
+    void        trace_eval() const;
     OptionsMap& get_options();
 
    private:
@@ -76,6 +90,8 @@ class Engine {
     ThreadPool           threads;
     TranspositionTable   tt;
     Eval::NNUE::Networks networks;
+
+    Search::SearchManager::UpdateContext updateContext;
 };
 
 }  // namespace Stockfish

src/main.cpp

@@ -21,9 +21,9 @@
 #include "bitboard.h"
 #include "misc.h"
 #include "position.h"
-#include "tune.h"
 #include "types.h"
 #include "uci.h"
+#include "tune.h"
 
 using namespace Stockfish;
 
@@ -35,6 +35,9 @@ int main(int argc, char* argv[]) {
     Position::init();
 
     UCIEngine uci(argc, argv);
+
+    Tune::init(uci.engine_options());
+
     uci.loop();
 
     return 0;

src/score.cpp

@@ -0,0 +1,48 @@
+/*
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (C) 2004-2024 The Stockfish developers (see AUTHORS file)
+
+  Stockfish is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  Stockfish is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "score.h"
+
+#include <cassert>
+#include <cmath>
+#include <cstdlib>
+
+#include "uci.h"
+
+namespace Stockfish {
+
+Score::Score(Value v, const Position& pos) {
+    assert(-VALUE_INFINITE < v && v < VALUE_INFINITE);
+
+    if (std::abs(v) < VALUE_TB_WIN_IN_MAX_PLY)
+    {
+        score = InternalUnits{UCIEngine::to_cp(v, pos)};
+    }
+    else if (std::abs(v) <= VALUE_TB)
+    {
+        auto distance = VALUE_TB - std::abs(v);
+        score         = (v > 0) ? TBWin{distance} : TBWin{-distance};
+    }
+    else
+    {
+        auto distance = VALUE_MATE - std::abs(v);
+        score         = (v > 0) ? Mate{distance} : Mate{-distance};
+    }
+}
+
+}

src/score.h

@@ -0,0 +1,69 @@
+/*
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (C) 2004-2024 The Stockfish developers (see AUTHORS file)
+
+  Stockfish is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  Stockfish is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef SCORE_H_INCLUDED
+#define SCORE_H_INCLUDED
+
+#include <variant>
+#include <utility>
+
+#include "types.h"
+
+namespace Stockfish {
+
+class Position;
+
+class Score {
+   public:
+    struct Mate {
+        int plies;
+    };
+
+    struct TBWin {
+        int plies;
+    };
+
+    struct InternalUnits {
+        int value;
+    };
+
+    Score() = default;
+    Score(Value v, const Position& pos);
+
+    template<typename T>
+    bool is() const {
+        return std::holds_alternative<T>(score);
+    }
+
+    template<typename T>
+    T get() const {
+        return std::get<T>(score);
+    }
+
+    template<typename F>
+    decltype(auto) visit(F&& f) const {
+        return std::visit(std::forward<F>(f), score);
+    }
+
+   private:
+    std::variant<Mate, TBWin, InternalUnits> score;
+};
+
+}
+
+#endif  // #ifndef SCORE_H_INCLUDED