S人ving Privàte Ryän

Fixes problems with non-ASCII characters in paths. Fixes #3424.

Changes
- Bump the minimum supported Clang version to 11 to support std::filesystem
- Use std::optional for empty values instead of string sentinels like "None"
- Remove the FixedString class
- Move the EvalFile network path from the network struct to the engine
- Simplify parts of the command-line handling
- Remove the old dual-net logic from export_net
- And ofc we now support non-ascii paths for windows

Behavior Change
- Because the EvalFile is no longer part of the network, it won't be included in the hashing, thus the network sharing is no longer dependent on the EvalFile path
- As a result, if the binary version and network are the same, changing only the EvalFile location will now reuse the same shared network

This also fixes a master bug where:

```
export_net None
setoption name EvalFile value None
export_net None
Failed to export a net
```

would fail on the second export. With this patch, the second export succeeds.

Quick Fishtest Check that nets load like normal.
https://tests.stockfishchess.org/tests/view/6a455593f97ff95f787954da

<img width="833" height="1137" alt="image" src="https://github.com/user-attachments/assets/fffee63b-c63a-4d5e-b13d-87d58bc28c88" />

closes https://github.com/official-stockfish/Stockfish/pull/6937

No functional change

Co-authored-by: anematode <timothy.herchen@gmail.com>

.github/workflows/avx2_compilers.yml

@@ -22,7 +22,6 @@ jobs:
           - { name: gcc-15, comp: gcc, cxx: g++, image: "gcc:15" }
 
           # Using silkeh/clang for older versions
-          - { name: clang-10, comp: clang, cxx: clang++, image: "silkeh/clang:10", is_clang: true, ver: "10" }
           - { name: clang-11, comp: clang, cxx: clang++, image: "silkeh/clang:11", is_clang: true, ver: "11" }
           - { name: clang-12, comp: clang, cxx: clang++, image: "silkeh/clang:12", is_clang: true, ver: "12" }
           - { name: clang-13, comp: clang, cxx: clang++, image: "silkeh/clang:13", is_clang: true, ver: "13" }

src/engine.cpp

@@ -20,6 +20,7 @@
 
 #include <algorithm>
 #include <cassert>
+#include <filesystem>
 #include <deque>
 #include <iosfwd>
 #include <memory>
@@ -33,7 +34,6 @@
 #include "misc.h"
 #include "nnue/network.h"
 #include "nnue/nnue_common.h"
-#include "nnue/nnue_misc.h"
 #include "numa.h"
 #include "perft.h"
 #include "position.h"
@@ -57,18 +57,19 @@ int           MaxThreads = std::max(1024, 4 * int(get_hardware_concurrency()));
 // PR#6526). The user can always explicitly override this behavior.
 constexpr NumaAutoPolicy DefaultNumaPolicy = BundledL3Policy{32};
 
-Engine::Engine(std::optional<std::string> path) :
+Engine::Engine(std::optional<std::filesystem::path> path) :
-    binaryDirectory(path ? CommandLine::get_binary_directory(*path) : ""),
+    binaryDirectory(path ? CommandLine::get_binary_directory(*path) : std::filesystem::path{}),
     numaContext(NumaConfig::from_system(DefaultNumaPolicy)),
     states(new std::deque<StateInfo>(1)),
     threads(),
-    network(numaContext, get_default_network()) {
+    networkFile{std::nullopt, ""},
+    network(numaContext) {
 
     pos.set(StartFEN, false, &states->back());
 
     options.add(  //
       "Debug Log File", Option("", [](const Option& o) {
-          start_logger(o);
+          start_logger(path_from_utf8(std::string(o)));
           return std::nullopt;
       }));
 
@@ -133,10 +134,11 @@ Engine::Engine(std::optional<std::string> path) :
 
     options.add(  //
       "EvalFile", Option(EvalFileDefaultName, [this](const Option& o) {
-          load_network(o);
+          load_network(path_from_utf8(std::string(o)));
           return std::nullopt;
       }));
 
+    network = get_default_network();
     threads.clear();
     threads.ensure_network_replicated();
     resize_threads();
@@ -256,7 +258,8 @@ void Engine::set_ponderhit(bool b) { threads.main_manager()->ponder = b; }
 // network related
 
 void Engine::verify_network() const {
-    network->verify(options["EvalFile"], onVerifyNetwork);
+    const auto file = path_from_utf8(std::string(options["EvalFile"]));
+    network->verify(onVerifyNetwork, networkFile, file);
 
     auto statuses = network.get_status_and_errors();
     for (usize i = 0; i < statuses.size(); ++i)
@@ -289,24 +292,25 @@ void Engine::verify_network() const {
     }
 }
 
-std::unique_ptr<Eval::NNUE::Network> Engine::get_default_network() const {
+std::unique_ptr<Eval::NNUE::Network> Engine::get_default_network() {
 
-    auto network_ = std::make_unique<NN::Network>(NN::EvalFile{EvalFileDefaultName, "None", ""});
+    auto network_ = std::make_unique<NN::Network>();
 
-    network_->load(binaryDirectory, "");
+    network_->load(binaryDirectory, std::filesystem::path{}, networkFile);
 
     return network_;
 }
 
-void Engine::load_network(const std::string& file) {
+void Engine::load_network(const std::filesystem::path& file) {
     network.modify_and_replicate(
-      [this, &file](NN::Network& network_) { network_.load(binaryDirectory, file); });
+      [this, &file](NN::Network& network_) { network_.load(binaryDirectory, file, networkFile); });
     threads.clear();
     threads.ensure_network_replicated();
 }
 
-void Engine::save_network(const std::pair<std::optional<std::string>, std::string> file) {
+void Engine::save_network(const std::optional<std::filesystem::path>& file) {
-    network.modify_and_replicate([&file](NN::Network& network_) { network_.save(file.first); });
+    network.modify_and_replicate(
+      [&file, this](NN::Network& network_) { network_.save(networkFile, file); });
 }
 
 // utility functions

src/engine.h

@@ -20,6 +20,7 @@
 #define ENGINE_H_INCLUDED
 
 #include <functional>
+#include <filesystem>
 #include <map>
 #include <memory>
 #include <optional>
@@ -31,6 +32,7 @@
 #include "misc.h"
 #include "history.h"
 #include "nnue/network.h"
+#include "nnue/nnue_misc.h"
 #include "numa.h"
 #include "position.h"
 #include "search.h"
@@ -47,7 +49,7 @@ class Engine {
     using InfoFull  = Search::InfoFull;
     using InfoIter  = Search::InfoIteration;
 
-    Engine(std::optional<std::string> path = std::nullopt);
+    Engine(std::optional<std::filesystem::path> path = std::nullopt);
 
     // Cannot be movable due to components holding backreferences to fields
     Engine(const Engine&)            = delete;
@@ -87,9 +89,9 @@ class Engine {
     // network related
 
     void                                 verify_network() const;
-    std::unique_ptr<Eval::NNUE::Network> get_default_network() const;
+    std::unique_ptr<Eval::NNUE::Network> get_default_network();
-    void                                 load_network(const std::string& file);
+    void                                 load_network(const std::filesystem::path& file);
-    void save_network(std::pair<std::optional<std::string>, std::string> file);
+    void save_network(const std::optional<std::filesystem::path>& file);
 
     // utility functions
 
@@ -110,7 +112,7 @@ class Engine {
     std::string                          thread_binding_information_as_string() const;
 
    private:
-    const std::string binaryDirectory;
+    const std::filesystem::path binaryDirectory;
 
     NumaReplicationContext numaContext;
 
@@ -120,6 +122,7 @@ class Engine {
     OptionsMap                                        options;
     ThreadPool                                        threads;
     TranspositionTable                                tt;
+    Eval::NNUE::EvalFile                              networkFile;
     LazyNumaReplicatedSystemWide<Eval::NNUE::Network> network;
 
     Search::SearchManager::UpdateContext  updateContext;

src/main.cpp

@@ -18,6 +18,7 @@
 
 #include <iostream>
 #include <memory>
+#include <utility>
 
 #include "attacks.h"
 #include "bitboard.h"
@@ -43,7 +44,8 @@ int main(int argc, char* argv[]) {
     Attacks::init();
     Position::init();
 
-    auto uci = std::make_unique<UCIEngine>(argc, argv);
+    auto cli = CommandLine(argc, argv);
+    auto uci = std::make_unique<UCIEngine>(std::move(cli));
 
     Tune::init(uci->engine_options());
 

src/misc.cpp

@@ -22,8 +22,10 @@
 #include <atomic>
 #include <cassert>
 #include <cctype>
+#include <cstring>
 #include <cmath>
 #include <cstdlib>
+#include <filesystem>
 #include <fstream>
 #include <iomanip>
 #include <iostream>
@@ -33,10 +35,21 @@
 #include <sstream>
 #include <string_view>
 
+#if defined(_WIN32)
+    #ifndef NOMINMAX
+        #define NOMINMAX
+    #endif
+    #include <direct.h>
+    #include <windows.h>
+    #include <shellapi.h>
+#endif
+
 #include "types.h"
 
 namespace Stockfish {
 
+namespace fs = std::filesystem;
+
 namespace {
 
 // Version number or dev.
@@ -83,7 +96,7 @@ class Logger {
     Tie           in, out;
 
    public:
-    static void start(const std::string& fname) {
+    static void start(const fs::path& fname) {
 
         static Logger l;
 
@@ -474,16 +487,61 @@ u64 hash_bytes(const char* data, usize size) {
 }
 
 // Trampoline helper to avoid moving Logger to misc.h
-void start_logger(const std::string& fname) { Logger::start(fname); }
+void start_logger(const fs::path& fname) { Logger::start(fname); }
-
 
+std::string utf8_from_wstring(std::wstring_view s) {
 #ifdef _WIN32
-    #include <direct.h>
+    if (s.empty())
-    #define GETCWD _getcwd
+        return {};
+
+    int size =
+      WideCharToMultiByte(CP_UTF8, 0, s.data(), int(s.size()), nullptr, 0, nullptr, nullptr);
+    if (size <= 0)
+        return {};
+
+    std::string out(size, '\0');
+    WideCharToMultiByte(CP_UTF8, 0, s.data(), int(s.size()), out.data(), size, nullptr, nullptr);
+    return out;
 #else
-    #include <unistd.h>
+    return std::string(s.begin(), s.end());
-    #define GETCWD getcwd
 #endif
+}
+
+fs::path path_from_utf8(const std::string& path) {
+#ifdef _WIN32
+    int u8len = static_cast<int>(path.size());
+    int wlen  = MultiByteToWideChar(CP_UTF8, 0, path.c_str(), u8len, NULL, 0);
+
+    std::wstring wstr(static_cast<usize>(wlen), L'\0');
+    MultiByteToWideChar(CP_UTF8, 0, path.c_str(), u8len, wstr.data(), wlen);
+    return {wstr};
+#else
+    return {path};
+#endif
+}
+
+CommandLine::CommandLine(int _argc, char** _argv) :
+    argc(_argc),
+    argv(_argv) {
+#ifdef _WIN32
+    // Convert any non-ANSI characters passed on the command line to UTF-8
+    int wargc = 0;
+    if (LPWSTR* wargv = CommandLineToArgvW(GetCommandLineW(), &wargc))
+    {
+        for (int i = 0; i < wargc; ++i)
+            argv_storage.push_back(utf8_from_wstring(wargv[i]));
+        LocalFree(wargv);
+
+        for (std::string& s : argv_storage)
+            argv_utf8.push_back(s.data());
+        argv_utf8.push_back(nullptr);
+
+        argc = wargc;
+        argv = argv_utf8.data();
+    }
+#endif
+}
+
 
 usize str_to_size_t(const std::string& s) {
     unsigned long long value = std::stoull(s);
@@ -507,49 +565,30 @@ bool is_whitespace(std::string_view s) {
     return std::all_of(s.begin(), s.end(), [](char c) { return std::isspace(c); });
 }
 
-std::string CommandLine::get_binary_directory(std::string argv0) {
+fs::path CommandLine::get_binary_directory(fs::path argv0) {
-    std::string pathSeparator;
 
 #ifdef _WIN32
-    pathSeparator = "\\";
     #ifdef _MSC_VER
-    // Under windows argv[0] may not have the extension. Also _get_pgmptr() had
+    // Prefer the executable path reported by the CRT when available.
-    // issues in some Windows 10 versions, so check returned values carefully.
+    wchar_t* pgmptr = nullptr;
-    char* pgmptr = nullptr;
+    if (!_get_wpgmptr(&pgmptr) && pgmptr != nullptr && *pgmptr)
-    if (!_get_pgmptr(&pgmptr) && pgmptr != nullptr && *pgmptr)
+        argv0 = fs::path(pgmptr);
-        argv0 = pgmptr;
     #endif
-#else
-    pathSeparator = "/";
 #endif
 
-    // Extract the working directory
+    auto binaryDirectory = argv0.parent_path();
-    auto workingDirectory = CommandLine::get_working_directory();
+    if (binaryDirectory.empty())
-
+        binaryDirectory = fs::path(".");
-    // Extract the binary directory path from argv0
-    auto  binaryDirectory = argv0;
-    usize pos             = binaryDirectory.find_last_of("\\/");
-    if (pos == std::string::npos)
-        binaryDirectory = "." + pathSeparator;
-    else
-        binaryDirectory.resize(pos + 1);
-
-    // Pattern replacement: "./" at the start of path is replaced by the working directory
-    if (binaryDirectory.find("." + pathSeparator) == 0)
-        binaryDirectory.replace(0, 1, workingDirectory);
-
     return binaryDirectory;
 }
 
-std::string CommandLine::get_working_directory() {
+fs::path CommandLine::get_working_directory() { return std::filesystem::current_path(); }
-    std::string workingDirectory = "";
-    char        buff[40000];
-    char*       cwd = GETCWD(buff, 40000);
-    if (cwd)
-        workingDirectory = cwd;
 
-    return workingDirectory;
+void set_console_utf8() {
+#ifdef _WIN32
+    SetConsoleCP(CP_UTF8);
+    SetConsoleOutputCP(CP_UTF8);
+#endif
 }
 
-
 }  // namespace Stockfish

src/misc.h

@@ -30,10 +30,9 @@
 #include <exception>  // IWYU pragma: keep
 // IWYU pragma: no_include <__exception/terminate.h>
 #include <functional>
+#include <filesystem>
 #include <iosfwd>
 #include <optional>
-#include <cstring>
-#include <memory>
 #include <string>
 #include <string_view>
 #include <type_traits>
@@ -132,10 +131,13 @@ void prefetch(const void* addr) {
 }
 #endif
 
-void start_logger(const std::string& fname);
+void start_logger(const std::filesystem::path& fname);
 
 usize str_to_size_t(const std::string& s);
 
+std::string           utf8_from_wstring(std::wstring_view s);
+std::filesystem::path path_from_utf8(const std::string& path);
+
 #if defined(__linux__)
 
 struct PipeDeleter {
@@ -524,88 +526,26 @@ inline void hash_combine(usize& seed, const T& v) {
 
 inline u64 hash_string(const std::string& sv) { return hash_bytes(sv.data(), sv.size()); }
 
-template<usize Capacity>
-class FixedString {
-   public:
-    FixedString() :
-        length_(0) {
-        data_[0] = '\0';
-    }
-
-    FixedString(const char* str) {
-        usize len = std::strlen(str);
-        if (len > Capacity)
-            std::terminate();
-        std::memcpy(data_, str, len);
-        length_        = len;
-        data_[length_] = '\0';
-    }
-
-    FixedString(const std::string& str) {
-        if (str.size() > Capacity)
-            std::terminate();
-        std::memcpy(data_, str.data(), str.size());
-        length_        = str.size();
-        data_[length_] = '\0';
-    }
-
-    usize size() const { return length_; }
-    usize capacity() const { return Capacity; }
-
-    const char* c_str() const { return data_; }
-    const char* data() const { return data_; }
-
-    char& operator[](usize i) { return data_[i]; }
-
-    const char& operator[](usize i) const { return data_[i]; }
-
-    FixedString& operator+=(const char* str) {
-        usize len = std::strlen(str);
-        if (length_ + len > Capacity)
-            std::terminate();
-        std::memcpy(data_ + length_, str, len);
-        length_ += len;
-        data_[length_] = '\0';
-        return *this;
-    }
-
-    FixedString& operator+=(const FixedString& other) { return (*this += other.c_str()); }
-
-    operator std::string() const { return std::string(data_, length_); }
-
-    operator std::string_view() const { return std::string_view(data_, length_); }
-
-    template<typename T>
-    bool operator==(const T& other) const noexcept {
-        return (std::string_view) (*this) == other;
-    }
-
-    template<typename T>
-    bool operator!=(const T& other) const noexcept {
-        return (std::string_view) (*this) != other;
-    }
-
-    void clear() {
-        length_  = 0;
-        data_[0] = '\0';
-    }
-
-   private:
-    char  data_[Capacity + 1];  // +1 for null terminator
-    usize length_;
-};
-
 struct CommandLine {
    public:
-    CommandLine(int _argc, char** _argv) :
+    CommandLine(int _argc, char** _argv);
-        argc(_argc),
-        argv(_argv) {}
 
-    static std::string get_binary_directory(std::string argv0);
+    CommandLine(const CommandLine&)            = delete;
-    static std::string get_working_directory();
+    CommandLine& operator=(const CommandLine&) = delete;
+    CommandLine(CommandLine&&)                 = default;
+    CommandLine& operator=(CommandLine&&)      = default;
+
+    static std::filesystem::path get_binary_directory(std::filesystem::path argv0);
+    static std::filesystem::path get_working_directory();
 
     int    argc;
     char** argv;
+
+   private:
+#ifdef _WIN32
+    std::vector<std::string> argv_storage;
+    std::vector<char*>       argv_utf8;
+#endif
 };
 
 namespace Utility {
@@ -666,13 +606,8 @@ void move_to_front(std::vector<T>& vec, Predicate pred) {
     #define RESTRICT
 #endif
 
+void set_console_utf8();
+
 }  // namespace Stockfish
 
-template<Stockfish::usize N>
-struct std::hash<Stockfish::FixedString<N>> {
-    Stockfish::usize operator()(const Stockfish::FixedString<N>& fstr) const noexcept {
-        return Stockfish::hash_bytes(fstr.data(), fstr.size());
-    }
-};
-
 #endif  // #ifndef MISC_H_INCLUDED

src/nnue/network.cpp

@@ -24,6 +24,7 @@
 #include <optional>
 #include <type_traits>
 #include <vector>
+#include <filesystem>
 
 #define INCBIN_SILENCE_BITCODE_WARNING
 #include "../incbin/incbin.h"
@@ -58,8 +59,10 @@ const unsigned char gEmbeddedNNUEData[1] = {0x0};
 const unsigned int  gEmbeddedNNUESize    = 1;
 #endif
 
+
 namespace Stockfish::Eval::NNUE {
 
+namespace fs = std::filesystem;
 
 namespace Detail {
 
@@ -84,60 +87,56 @@ bool write_parameters(std::ostream& stream, const T& reference) {
 
 }  // namespace Detail
 
-void Network::load(const std::string& rootDirectory, std::string evalfilePath) {
+void Network::load(const fs::path& rootDirectory, fs::path evalfilePath, EvalFile& evalFile) {
 #if defined(DEFAULT_NNUE_DIRECTORY)
-    std::vector<std::string> dirs = {"<internal>", "", rootDirectory,
+    std::vector<fs::path> dirs = {fs::path{}, rootDirectory,
-                                     stringify(DEFAULT_NNUE_DIRECTORY)};
+                                  fs::path(stringify(DEFAULT_NNUE_DIRECTORY))};
 #else
-    std::vector<std::string> dirs = {"<internal>", "", rootDirectory};
+    std::vector<fs::path> dirs = {fs::path{}, rootDirectory};
 #endif
 
     if (evalfilePath.empty())
         evalfilePath = evalFile.defaultName;
 
+    if (evalFile.current != evalfilePath && evalfilePath == evalFile.defaultName)
+        load_internal(evalFile);
+
     for (const auto& directory : dirs)
     {
-        if (std::string(evalFile.current) != evalfilePath)
+        if (evalFile.current != evalfilePath)
-        {
+            load_external(directory, evalfilePath, evalFile);
-            if (directory != "<internal>")
-                load_user_net(directory, evalfilePath);
-            else if (evalfilePath == std::string(evalFile.defaultName))
-                load_internal();
-        }
     }
 }
 
-
+bool Network::save(const EvalFile& evalFile, const std::optional<fs::path>& filename) const {
-bool Network::save(const std::optional<std::string>& filename) const {
+    if (!evalFile.current.has_value())
-    std::string actualFilename;
-    std::string msg;
-
-    if (filename.has_value())
-        actualFilename = filename.value();
-    else
     {
-        if (std::string(evalFile.current) != std::string(evalFile.defaultName))
+        sync_cout << "Failed to export a net. No network file is currently loaded. "
-        {
+                     "Please load a network file first."
-            msg = "Failed to export a net. "
+                  << sync_endl;
-                  "A non-embedded net can only be saved if the filename is specified";
-
-            sync_cout << msg << sync_endl;
         return false;
     }
 
-        actualFilename = evalFile.defaultName;
+    if (!filename.has_value() && evalFile.current != evalFile.defaultName)
+    {
+        sync_cout << "Failed to export a net. A non-embedded net can only be "
+                     "saved if the filename is specified"
+                  << sync_endl;
+        return false;
     }
 
+    fs::path      actualFilename = filename.value_or(evalFile.defaultName);
     std::ofstream stream(actualFilename, std::ios_base::binary);
-    bool          saved = save(stream, evalFile.current, evalFile.netDescription);
 
-    msg = saved ? "Network saved successfully to " + actualFilename : "Failed to export a net";
+    bool saved = save(stream, evalFile.netDescription);
+
+    sync_cout << (saved ? "Network saved successfully to " + actualFilename.string()
+                        : "Failed to export a net")
+              << sync_endl;
 
-    sync_cout << msg << sync_endl;
     return saved;
 }
 
-
 NetworkOutput Network::evaluate(const Position&    pos,
                                 AccumulatorStack&  accumulatorStack,
                                 AccumulatorCaches& cache) const {
@@ -158,18 +157,20 @@ NetworkOutput Network::evaluate(const Position&    pos,
 }
 
 
-void Network::verify(std::string                                  evalfilePath,
+void Network::verify(const std::function<void(std::string_view)>& f,
-                     const std::function<void(std::string_view)>& f) const {
+                     const EvalFile&                              evalFile,
+                     fs::path                                     evalfilePath) const {
     if (evalfilePath.empty())
         evalfilePath = evalFile.defaultName;
 
-    if (std::string(evalFile.current) != evalfilePath)
+    if (evalFile.current != evalfilePath)
     {
         if (f)
         {
             std::string msg1 =
               "Network evaluation parameters compatible with the engine must be available.";
-            std::string msg2 = "The network file " + evalfilePath + " was not loaded successfully.";
+            std::string msg2 =
+              "The network file " + evalfilePath.string() + " was not loaded successfully.";
             std::string msg3 = "The UCI option EvalFile might need to specify the full path, "
                                "including the directory name, to the network file.";
             std::string msg4 = "The default net can be downloaded from: "
@@ -189,8 +190,9 @@ void Network::verify(std::string                                  evalfilePath,
     if (f)
     {
         usize size = sizeof(featureTransformer) + sizeof(NetworkArchitecture) * LayerStacks;
-        f("NNUE evaluation using " + evalfilePath + " (" + std::to_string(size / (1024 * 1024))
+        f("NNUE evaluation using " + evalfilePath.string() + " ("
-          + "MiB, (" + std::to_string(featureTransformer.InputDimensions) + ", "
+          + std::to_string(size / (1024 * 1024)) + "MiB, ("
+          + std::to_string(featureTransformer.InputDimensions) + ", "
           + std::to_string(network[0].TransformedFeatureDimensions) + ", "
           + std::to_string(network[0].FC_0_OUTPUTS) + ", " + std::to_string(network[0].FC_1_OUTPUTS)
           + ", 1))");
@@ -225,8 +227,8 @@ NnueEvalTrace Network::trace_evaluate(const Position&    pos,
 }
 
 
-void Network::load_user_net(const std::string& dir, const std::string& evalfilePath) {
+void Network::load_external(const fs::path& dir, const fs::path& evalfilePath, EvalFile& evalFile) {
-    std::ifstream stream(dir + evalfilePath, std::ios::binary);
+    std::ifstream stream(dir / evalfilePath, std::ios::binary);
     auto          description = load(stream);
 
     if (description.has_value())
@@ -237,7 +239,7 @@ void Network::load_user_net(const std::string& dir, const std::string& evalfileP
 }
 
 
-void Network::load_internal() {
+void Network::load_internal(EvalFile& evalFile) {
     // C++ way to prepare a buffer for a memory stream
     class MemoryBuffer: public std::basic_streambuf<char> {
        public:
@@ -269,12 +271,7 @@ void Network::load_internal() {
 void Network::initialize() { initialized = true; }
 
 
-bool Network::save(std::ostream&      stream,
+bool Network::save(std::ostream& stream, const std::string& netDescription) const {
-                   const std::string& name,
-                   const std::string& netDescription) const {
-    if (name.empty() || name == "None")
-        return false;
-
     return write_parameters(stream, netDescription);
 }
 
@@ -295,7 +292,6 @@ usize Network::get_content_hash() const {
     hash_combine(h, featureTransformer);
     for (auto&& layerstack : network)
         hash_combine(h, layerstack);
-    hash_combine(h, evalFile);
     return h;
 }
 

src/nnue/network.h

@@ -26,6 +26,7 @@
 #include <string>
 #include <string_view>
 #include <tuple>
+#include <filesystem>
 
 #include "../types.h"
 #include "../misc.h"
@@ -49,8 +50,7 @@ using NetworkOutput = std::tuple<Value, Value>;
 // there is no way to run destructors.
 class Network {
    public:
-    Network(EvalFile file) :
+    Network() = default;
-        evalFile(file) {}
 
     Network(const Network& other) = default;
     Network(Network&& other)      = default;
@@ -58,8 +58,10 @@ class Network {
     Network& operator=(const Network& other) = default;
     Network& operator=(Network&& other)      = default;
 
-    void load(const std::string& rootDirectory, std::string evalfilePath);
+    void load(const std::filesystem::path& rootDirectory,
-    bool save(const std::optional<std::string>& filename) const;
+              std::filesystem::path        evalfilePath,
+              EvalFile&                    evalFile);
+    bool save(const EvalFile& evalFile, const std::optional<std::filesystem::path>& filename) const;
 
     usize get_content_hash() const;
 
@@ -68,18 +70,21 @@ class Network {
                            AccumulatorCaches& cache) const;
 
 
-    void verify(std::string evalfilePath, const std::function<void(std::string_view)>&) const;
+    void verify(const std::function<void(std::string_view)>& f,
+                const EvalFile&                              evalFile,
+                std::filesystem::path                        evalfilePath) const;
+
     NnueEvalTrace trace_evaluate(const Position&    pos,
                                  AccumulatorStack&  accumulatorStack,
                                  AccumulatorCaches& cache) const;
 
-   private:
+    void load_external(const std::filesystem::path&, const std::filesystem::path&, EvalFile&);
-    void load_user_net(const std::string&, const std::string&);
+    void load_internal(EvalFile&);
-    void load_internal();
 
+   private:
     void initialize();
 
-    bool                       save(std::ostream&, const std::string&, const std::string&) const;
+    bool                       save(std::ostream&, const std::string&) const;
     std::optional<std::string> load(std::istream&);
 
     bool read_header(std::istream&, u32*, std::string*) const;
@@ -94,8 +99,6 @@ class Network {
     // Evaluation function
     NetworkArchitecture network[LayerStacks];
 
-    EvalFile evalFile;
-
     bool initialized = false;
 
     // Hash value of evaluation function structure

src/nnue/nnue_misc.cpp

@@ -25,6 +25,7 @@
 #include <iomanip>
 #include <iosfwd>
 #include <iostream>
+#include <memory>
 #include <sstream>
 
 #include "../position.h"

src/nnue/nnue_misc.h

@@ -19,12 +19,15 @@
 #ifndef NNUE_MISC_H_INCLUDED
 #define NNUE_MISC_H_INCLUDED
 
-#include <memory>
 #include <string>
+#include <string_view>
+#include <optional>
+#include <filesystem>
 
 #include "../misc.h"
 #include "../types.h"
 #include "nnue_architecture.h"
+#include "../evaluate.h"
 
 namespace Stockfish {
 
@@ -32,15 +35,16 @@ class Position;
 
 namespace Eval::NNUE {
 
-// EvalFile uses fixed string types because it's part of the network structure which must be trivial.
+// NNUE file metadata uses fixed string types so it stays trivially copyable and cheap to move
+// around between the engine and the network loader.
 struct EvalFile {
     // Default net name, will use one of the EvalFileDefaultName* macros defined
     // in evaluate.h
-    FixedString<256> defaultName;
+    constexpr static std::string_view defaultName = EvalFileDefaultName;
     // Selected net name, either via uci option or default
-    FixedString<256> current;
+    std::optional<std::filesystem::path> current;
     // Net description extracted from the net file
-    FixedString<256> netDescription;
+    std::string netDescription;
 };
 
 struct NnueEvalTrace {
@@ -59,15 +63,4 @@ std::string trace(Position& pos, const Network& network, AccumulatorCaches& cach
 }  // namespace Stockfish::Eval::NNUE
 }  // namespace Stockfish
 
-template<>
-struct std::hash<Stockfish::Eval::NNUE::EvalFile> {
-    Stockfish::usize operator()(const Stockfish::Eval::NNUE::EvalFile& evalFile) const noexcept {
-        Stockfish::usize h = 0;
-        Stockfish::hash_combine(h, evalFile.defaultName);
-        Stockfish::hash_combine(h, evalFile.current);
-        Stockfish::hash_combine(h, evalFile.netDescription);
-        return h;
-    }
-};
-
 #endif  // #ifndef NNUE_MISC_H_INCLUDED

src/syzygy/tbprobe.cpp

@@ -32,6 +32,7 @@
 #include <optional>
 #include <sstream>
 #include <string_view>
+#include <filesystem>
 #include <sys/stat.h>
 #include <type_traits>
 #include <utility>
@@ -227,7 +228,7 @@ static_assert(sizeof(LR) == 3, "LR tree entry must be 3 bytes");
 // time only existence of the file is checked.
 class TBFile: public std::ifstream {
 
-    std::string fname;
+    std::filesystem::path fname;
 
    public:
     // Look for and open the file among the Paths directories where the .rtbw
@@ -236,21 +237,13 @@ class TBFile: public std::ifstream {
     //
     // Example:
     // C:\tb\wdl345;C:\tb\wdl6;D:\tb\dtz345;D:\tb\dtz6
-    static std::string Paths;
+    static std::vector<std::filesystem::path> Paths;
 
     TBFile(const std::string& f) {
 
-    #ifndef _WIN32
+        for (const auto& path : Paths)
-        constexpr char SepChar = ':';
-    #else
-        constexpr char SepChar = ';';
-    #endif
-        std::stringstream ss(Paths);
-        std::string       path;
-
-        while (std::getline(ss, path, SepChar))
         {
-            fname = path + "/" + f;
+            fname = path / std::filesystem::path(f);
             std::ifstream::open(fname);
             if (is_open())
                 return;
@@ -273,7 +266,7 @@ class TBFile: public std::ifstream {
 
         if (statbuf.st_size % 64 != 16)
         {
-            std::cerr << "Corrupt tablebase file " << fname << std::endl;
+            std::cerr << "Corrupt tablebase file " << fname.string() << std::endl;
             exit(EXIT_FAILURE);
         }
 
@@ -286,12 +279,12 @@ class TBFile: public std::ifstream {
 
         if (*baseAddress == MAP_FAILED)
         {
-            std::cerr << "Could not mmap() " << fname << std::endl;
+            std::cerr << "Could not mmap() " << fname.string() << std::endl;
             exit(EXIT_FAILURE);
         }
     #else
         // Note FILE_FLAG_RANDOM_ACCESS is only a hint to Windows and as such may get ignored.
-        HANDLE fd = CreateFileA(fname.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr,
+        HANDLE fd = CreateFileW(fname.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr,
                                 OPEN_EXISTING, FILE_FLAG_RANDOM_ACCESS, nullptr);
 
         if (fd == INVALID_HANDLE_VALUE)
@@ -302,7 +295,7 @@ class TBFile: public std::ifstream {
 
         if (size_low % 64 != 16)
         {
-            std::cerr << "Corrupt tablebase file " << fname << std::endl;
+            std::cerr << "Corrupt tablebase file " << fname.string() << std::endl;
             exit(EXIT_FAILURE);
         }
 
@@ -320,7 +313,7 @@ class TBFile: public std::ifstream {
 
         if (!*baseAddress)
         {
-            std::cerr << "MapViewOfFile() failed, name = " << fname
+            std::cerr << "MapViewOfFile() failed, name = " << fname.string()
                       << ", error = " << GetLastError() << std::endl;
             exit(EXIT_FAILURE);
         }
@@ -331,7 +324,7 @@ class TBFile: public std::ifstream {
 
         if (memcmp(data, Magics[type == WDL], 4))
         {
-            std::cerr << "Corrupted table in file " << fname << std::endl;
+            std::cerr << "Corrupted table in file " << fname.string() << std::endl;
             unmap(*baseAddress, *mapping);
             return *baseAddress = nullptr, nullptr;
         }
@@ -350,7 +343,7 @@ class TBFile: public std::ifstream {
     }
 };
 
-std::string TBFile::Paths;
+std::vector<std::filesystem::path> TBFile::Paths;
 
 // struct PairsData contains low-level indexing information to access TB data.
 // There are 8, 4, or 2 PairsData records for each TBTable, according to the type
@@ -1405,9 +1398,24 @@ void Tablebases::init(const std::string& paths) {
 
     TBTables.clear();
     MaxCardinality = 0;
-    TBFile::Paths  = paths;
+    TBFile::Paths.clear();
 
-    if (paths.empty())
+    if (!paths.empty())
+    {
+    #ifndef _WIN32
+        constexpr char SepChar = ':';
+    #else
+        constexpr char SepChar = ';';
+    #endif
+
+        std::stringstream ss(paths);
+        std::string       path;
+        while (std::getline(ss, path, SepChar))
+            if (!path.empty())
+                TBFile::Paths.emplace_back(path_from_utf8(path));
+    }
+
+    if (TBFile::Paths.empty())
         return;
 
     // MapB1H1H7[] encodes a square below a1-h8 diagonal to 0..27

src/types.h

@@ -65,8 +65,8 @@
     #endif
 
     // Enforce minimum Clang version
-    #if defined(__clang__) && (__clang_major__ < 10)
+    #if defined(__clang__) && (__clang_major__ < 11)
-        #error "Stockfish requires Clang 10.0 or later for correct compilation"
+        #error "Stockfish requires Clang 11.0 or later for correct compilation"
     #endif
 
     #define ASSERT_ALIGNED(ptr, alignment) assert(reinterpret_cast<uintptr_t>(ptr) % alignment == 0)

src/uci.cpp

@@ -26,6 +26,7 @@
 #include <optional>
 #include <sstream>
 #include <string_view>
+#include <filesystem>
 #include <utility>
 #include <vector>
 
@@ -63,9 +64,9 @@ void UCIEngine::print_info_string(std::string_view str) {
     sync_cout_end();
 }
 
-UCIEngine::UCIEngine(int argc, char** argv) :
+UCIEngine::UCIEngine(CommandLine cli_) :
-    engine(argv[0]),
+    engine(cli_.argc > 0 ? std::optional{path_from_utf8(cli_.argv[0])} : std::nullopt),
-    cli(argc, argv) {
+    cli(std::move(cli_)) {
 
     engine.get_options().add_info_listener([](const std::optional<std::string>& str) {
         if (str.has_value())
@@ -85,6 +86,7 @@ void UCIEngine::init_search_update_listeners() {
 }
 
 void UCIEngine::loop() {
+    set_console_utf8();
     std::string token, cmd;
 
     for (int i = 1; i < cli.argc; ++i)
@@ -151,10 +153,11 @@ void UCIEngine::loop() {
             sync_cout << compiler_info() << sync_endl;
         else if (token == "export_net")
         {
-            std::pair<std::optional<std::string>, std::string> file;
+            std::optional<std::filesystem::path> file;
+            std::string                          filename;
 
-            if (is >> file.second)
+            if (is >> filename)
-                file.first = file.second;
+                file = path_from_utf8(filename);
 
             engine.save_network(file);
         }
@@ -171,7 +174,7 @@ void UCIEngine::loop() {
             sync_cout << "Unknown command: '" << cmd << "'. Type help for more information."
                       << sync_endl;
 
-    } while (token != "quit" && cli.argc == 1);  // The command-line arguments are one-shot
+    } while (token != "quit" && cli.argc <= 1);  // The command-line arguments are one-shot
 }
 
 Search::LimitsType UCIEngine::parse_limits(std::istream& is) {

src/uci.h

@@ -39,7 +39,7 @@ constexpr auto StartFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -
 
 class UCIEngine {
    public:
-    UCIEngine(int argc, char** argv);
+    UCIEngine(CommandLine cli);
 
     void loop();