Remove duplicated Position object in UCIEngine

Also fixes searchmoves.

Drop the need of a Position object in uci.cpp.

A side note, it is still required for the static functions,
but these should be moved to a different namespace/class
later on, since sf kinda relies on them.

closes https://github.com/official-stockfish/Stockfish/pull/5169

No functional change

src/benchmark.cpp

@@ -23,8 +23,6 @@
 #include <iostream>
 #include <vector>
 
-#include "position.h"
-
 namespace {
 
 // clang-format off
@@ -108,7 +106,7 @@ namespace Stockfish {
 // bench 64 1 100000 default nodes  : search default positions for 100K nodes each
 // bench 64 4 5000 current movetime : search current position with 4 threads for 5 sec
 // bench 16 1 5 blah perft          : run a perft 5 on positions in file "blah"
-std::vector<std::string> setup_bench(const Position& current, std::istream& is) {
+std::vector<std::string> setup_bench(const std::string& currentFen, std::istream& is) {
 
     std::vector<std::string> fens, list;
     std::string              go, token;
@@ -126,7 +124,7 @@ std::vector<std::string> setup_bench(const Position& current, std::istream& is)
         fens = Defaults;
 
     else if (fenFile == "current")
-        fens.push_back(current.fen());
+        fens.push_back(currentFen);
 
     else
     {

src/benchmark.h

@@ -25,9 +25,7 @@
 
 namespace Stockfish {
 
-class Position;
+std::vector<std::string> setup_bench(const std::string&, std::istream&);
-
-std::vector<std::string> setup_bench(const Position&, std::istream&);
 
 }  // namespace Stockfish
 

src/engine.cpp

@@ -24,6 +24,8 @@
 #include <string_view>
 #include <utility>
 #include <vector>
+#include <sstream>
+#include <iosfwd>
 
 #include "evaluate.h"
 #include "misc.h"
@@ -146,8 +148,6 @@ void Engine::save_network(const std::pair<std::optional<std::string>, std::strin
 
 // utility functions
 
-OptionsMap& Engine::get_options() { return options; }
-
 void Engine::trace_eval() const {
     StateListPtr trace_states(new std::deque<StateInfo>(1));
     Position     p;
@@ -158,4 +158,16 @@ void Engine::trace_eval() const {
     sync_cout << "\n" << Eval::trace(p, networks) << sync_endl;
 }
 
+OptionsMap& Engine::get_options() { return options; }
+
+std::string Engine::fen() const { return pos.fen(); }
+
+void Engine::flip() { pos.flip(); }
+
+std::string Engine::visualize() const {
+    std::stringstream ss;
+    ss << pos;
+    return ss.str();
+}
+
 }

src/engine.h

@@ -79,6 +79,9 @@ class Engine {
 
     void        trace_eval() const;
     OptionsMap& get_options();
+    std::string fen() const;
+    void        flip();
+    std::string visualize() const;
 
    private:
     const std::string binaryDirectory;

src/search.h

@@ -28,6 +28,7 @@
 #include <memory>
 #include <string_view>
 #include <vector>
+#include <string>
 
 #include "misc.h"
 #include "movepick.h"
@@ -121,7 +122,7 @@ struct LimitsType {
 
     bool use_time_management() const { return time[WHITE] || time[BLACK]; }
 
-    std::vector<Move> searchmoves;
+    std::vector<std::string> searchmoves;
     TimePoint                time[COLOR_NB], inc[COLOR_NB], npmsec, movetime, startTime;
     int                      movestogo, depth, mate, perft, infinite;
     uint64_t                 nodes;

src/thread.cpp

@@ -24,6 +24,7 @@
 #include <memory>
 #include <unordered_map>
 #include <utility>
+#include <string>
 
 #include "misc.h"
 #include "movegen.h"
@@ -33,6 +34,7 @@
 #include "tt.h"
 #include "types.h"
 #include "ucioption.h"
+#include "uci.h"
 
 namespace Stockfish {
 
@@ -182,10 +184,18 @@ void ThreadPool::start_thinking(const OptionsMap&  options,
     increaseDepth = true;
 
     Search::RootMoves rootMoves;
+    const auto        legalmoves = MoveList<LEGAL>(pos);
 
-    for (const auto& m : MoveList<LEGAL>(pos))
+    for (const auto& uciMove : limits.searchmoves)
-        if (limits.searchmoves.empty()
+    {
-            || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
+        auto move = UCIEngine::to_move(pos, uciMove);
+
+        if (std::find(legalmoves.begin(), legalmoves.end(), move) != legalmoves.end())
+            rootMoves.emplace_back(move);
+    }
+
+    if (rootMoves.empty())
+        for (const auto& m : legalmoves)
             rootMoves.emplace_back(m);
 
     Tablebases::Config tbConfig = Tablebases::rank_root_moves(options, pos, rootMoves);

src/uci.cpp

@@ -22,8 +22,6 @@
 #include <cctype>
 #include <cmath>
 #include <cstdint>
-#include <deque>
-#include <memory>
 #include <optional>
 #include <sstream>
 #include <string_view>
@@ -98,11 +96,7 @@ UCIEngine::UCIEngine(int argc, char** argv) :
 
 void UCIEngine::loop() {
 
-    Position     pos;
     std::string token, cmd;
-    StateListPtr states(new std::deque<StateInfo>(1));
-
-    pos.set(StartFEN, false, &states->back());
 
     for (int i = 1; i < cli.argc; ++i)
         cmd += std::string(cli.argv[i]) + " ";
@@ -135,9 +129,9 @@ void UCIEngine::loop() {
         else if (token == "setoption")
             setoption(is);
         else if (token == "go")
-            go(pos, is);
+            go(is);
         else if (token == "position")
-            position(pos, is);
+            position(is);
         else if (token == "ucinewgame")
             engine.search_clear();
         else if (token == "isready")
@@ -146,11 +140,11 @@ void UCIEngine::loop() {
         // Add custom non-UCI commands, mainly for debugging purposes.
         // These commands must not be used during a search!
         else if (token == "flip")
-            pos.flip();
+            engine.flip();
         else if (token == "bench")
-            bench(pos, is);
+            bench(is);
         else if (token == "d")
-            sync_cout << pos << sync_endl;
+            sync_cout << engine.visualize() << sync_endl;
         else if (token == "eval")
             engine.trace_eval();
         else if (token == "compiler")
@@ -183,7 +177,7 @@ void UCIEngine::loop() {
     } while (token != "quit" && cli.argc == 1);  // The command-line arguments are one-shot
 }
 
-Search::LimitsType UCIEngine::parse_limits(const Position& pos, std::istream& is) {
+Search::LimitsType UCIEngine::parse_limits(std::istream& is) {
     Search::LimitsType limits;
     std::string        token;
 
@@ -192,7 +186,7 @@ Search::LimitsType UCIEngine::parse_limits(const Position& pos, std::istream& is
     while (is >> token)
         if (token == "searchmoves")  // Needs to be the last command on the line
             while (is >> token)
-                limits.searchmoves.push_back(to_move(pos, token));
+                limits.searchmoves.push_back(to_lower(token));
 
         else if (token == "wtime")
             is >> limits.time[WHITE];
@@ -222,13 +216,13 @@ Search::LimitsType UCIEngine::parse_limits(const Position& pos, std::istream& is
     return limits;
 }
 
-void UCIEngine::go(Position& pos, std::istringstream& is) {
+void UCIEngine::go(std::istringstream& is) {
 
-    Search::LimitsType limits = parse_limits(pos, is);
+    Search::LimitsType limits = parse_limits(is);
     engine.go(limits);
 }
 
-void UCIEngine::bench(Position& pos, std::istream& args) {
+void UCIEngine::bench(std::istream& args) {
     std::string token;
     uint64_t    num, nodes = 0, cnt = 1;
     uint64_t    nodesSearched = 0;
@@ -239,7 +233,7 @@ void UCIEngine::bench(Position& pos, std::istream& args) {
         on_update_full(i, options["UCI_ShowWDL"]);
     });
 
-    std::vector<std::string> list = setup_bench(pos, args);
+    std::vector<std::string> list = setup_bench(engine.fen(), args);
 
     num = count_if(list.begin(), list.end(),
                    [](const std::string& s) { return s.find("go ") == 0 || s.find("eval") == 0; });
@@ -253,11 +247,11 @@ void UCIEngine::bench(Position& pos, std::istream& args) {
 
         if (token == "go" || token == "eval")
         {
-            std::cerr << "\nPosition: " << cnt++ << '/' << num << " (" << pos.fen() << ")"
+            std::cerr << "\nPosition: " << cnt++ << '/' << num << " (" << engine.fen() << ")"
                       << std::endl;
             if (token == "go")
             {
-                go(pos, is);
+                go(is);
                 engine.wait_for_search_finished();
                 nodes += nodesSearched;
                 nodesSearched = 0;
@@ -268,7 +262,7 @@ void UCIEngine::bench(Position& pos, std::istream& args) {
         else if (token == "setoption")
             setoption(is);
         else if (token == "position")
-            position(pos, is);
+            position(is);
         else if (token == "ucinewgame")
         {
             engine.search_clear();  // search_clear may take a while
@@ -294,7 +288,7 @@ void UCIEngine::setoption(std::istringstream& is) {
     engine.get_options().setoption(is);
 }
 
-void UCIEngine::position(Position& pos, std::istringstream& is) {
+void UCIEngine::position(std::istringstream& is) {
     std::string token, fen;
 
     is >> token;
@@ -317,7 +311,6 @@ void UCIEngine::position(Position& pos, std::istringstream& is) {
         moves.push_back(token);
     }
 
-    pos.set(fen, engine.get_options()["UCI_Chess960"], pos.state());
     engine.set_position(fen, moves);
 }
 
@@ -425,9 +418,14 @@ std::string UCIEngine::move(Move m, bool chess960) {
 }
 
 
+std::string UCIEngine::to_lower(std::string str) {
+    std::transform(str.begin(), str.end(), str.begin(), [](auto c) { return std::tolower(c); });
+
+    return str;
+}
+
 Move UCIEngine::to_move(const Position& pos, std::string str) {
-    if (str.length() == 5)
+    str = to_lower(str);
-        str[4] = char(tolower(str[4]));  // The promotion piece character must be lowercased
 
     for (const auto& m : MoveList<LEGAL>(pos))
         if (str == move(m, pos.is_chess960()))

src/uci.h

@@ -46,9 +46,10 @@ class UCIEngine {
     static std::string square(Square s);
     static std::string move(Move m, bool chess960);
     static std::string wdl(Value v, const Position& pos);
+    static std::string to_lower(std::string str);
     static Move        to_move(const Position& pos, std::string str);
 
-    static Search::LimitsType parse_limits(const Position& pos, std::istream& is);
+    static Search::LimitsType parse_limits(std::istream& is);
 
     auto& engine_options() { return engine.get_options(); }
 
@@ -56,9 +57,9 @@ class UCIEngine {
     Engine      engine;
     CommandLine cli;
 
-    void go(Position& pos, std::istringstream& is);
+    void go(std::istringstream& is);
-    void bench(Position& pos, std::istream& args);
+    void bench(std::istream& args);
-    void position(Position& pos, std::istringstream& is);
+    void position(std::istringstream& is);
     void setoption(std::istringstream& is);
 
     static void on_update_no_moves(const Engine::InfoShort& info);