Merge pull request #43 from OpenVicProject/add/vdf-search

5 files changed, 559 insertions, 2 deletions

diff --git a/.clang-format b/.clang-format
index a85ae5e..d1aab5d 100644
--- a/.clang-format
+++ b/.clang-format
@@ -56,7 +56,9 @@ IncludeCategories:
     Priority: 2
   - Regex: ^<openvic-dataloader/
     Priority: 3
-  - Regex: ^"openvic-simulation/
+  - Regex: ^<lexy-vdf/
     Priority: 4
-  - Regex: .*
+  - Regex: ^"openvic-simulation/
     Priority: 5
+  - Regex: .*
+    Priority: 6
diff --git a/src/openvic-simulation/dataloader/Dataloader.cpp b/src/openvic-simulation/dataloader/Dataloader.cpp
index 6469b63..70164c3 100644
--- a/src/openvic-simulation/dataloader/Dataloader.cpp
+++ b/src/openvic-simulation/dataloader/Dataloader.cpp
@@ -1,16 +1,319 @@
 #include "Dataloader.hpp"
 
+#include <array>
+#include <cstdlib>
+#include <filesystem>
+#include <optional>
+#include <string_view>
+#include <system_error>
+#include <type_traits>
+#include <variant>
+
 #include <openvic-dataloader/csv/Parser.hpp>
 #include <openvic-dataloader/detail/CallbackOStream.hpp>
 #include <openvic-dataloader/v2script/Parser.hpp>
 
+#include <lexy-vdf/KeyValues.hpp>
+#include <lexy-vdf/Parser.hpp>
+
 #include "openvic-simulation/GameManager.hpp"
+#include "openvic-simulation/utility/ConstexprIntToStr.hpp"
 #include "openvic-simulation/utility/Logger.hpp"
 
+#ifdef _WIN32
+#include <Windows.h>
+#include "Dataloader_Windows.hpp"
+#endif
+
+#if defined(__APPLE__) && defined(__MACH__)
+#include <TargetConditionals.h>
+#endif
+
 using namespace OpenVic;
 using namespace OpenVic::NodeTools;
 using namespace ovdl;
 
+// Windows and Mac by default act like case insensitive filesystems
+constexpr bool path_equals(std::string_view lhs, std::string_view rhs) {
+#if defined(_WIN32) || (defined(__APPLE__) && defined(__MACH__))
+	constexpr auto ichar_equals = [](unsigned char l, unsigned char r) {
+		return std::tolower(l) == std::tolower(r);
+	};
+	return std::equal(lhs.begin(), lhs.end(), rhs.begin(), rhs.end(), ichar_equals);
+#else
+	return std::equal(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
+#endif
+}
+
+template<typename LT, typename RT>
+constexpr bool filename_equals(const LT& lhs, const RT& rhs) {
+	std::string_view left, right;
+	if constexpr (std::same_as<LT, std::filesystem::path>)
+		left = lhs.filename().string();
+	else left = lhs;
+
+	if constexpr (std::same_as<RT, std::filesystem::path>)
+		right = rhs.filename().string();
+	else right = rhs;
+
+	return path_equals(left, right);
+}
+
+fs::path _search_for_game_path(fs::path hint_path = {}) {
+	// Apparently max amount of steam libraries is 8, if incorrect please correct it to the correct max amount
+	constexpr int max_amount_of_steam_libraries = 8;
+	constexpr std::string_view Victoria_2_folder = "Victoria 2";
+	constexpr std::string_view v2_game_exe = "v2game.exe";
+	constexpr std::string_view steamapps = "steamapps";
+	constexpr std::string_view libraryfolders = "libraryfolders.vdf";
+	constexpr std::string_view vic2_appmanifest = "appmanifest_42960.acf";
+	constexpr std::string_view common_folder = "common";
+
+	std::error_code error_code;
+
+	// Don't waste time trying to search for Victoria 2 when supplied a valid looking Victoria 2 game directory
+	if (filename_equals(Victoria_2_folder, hint_path)) {
+		if (fs::is_regular_file(hint_path / v2_game_exe, error_code))
+			return hint_path;
+	}
+
+	const bool hint_path_was_empty = hint_path.empty();
+	if (hint_path_was_empty) {
+#if defined(_WIN32)
+		static const fs::path registry_path = Windows::ReadRegValue<char>(HKEY_LOCAL_MACHINE, "SOFTWARE\\WOW6432Node\\Paradox Interactive\\Victoria 2", "path");
+
+		if (!registry_path.empty())
+			return registry_path;
+
+		#pragma warning(push)
+		#pragma warning(disable: 4996)
+		static const fs::path prog_files = std::string(std::getenv("ProgramFiles"));
+		hint_path = prog_files / "Steam";
+		if (!fs::is_directory(hint_path, error_code)) {
+			static const fs::path prog_files_x86 = std::string(std::getenv("ProgramFiles(x86)"));
+			hint_path = prog_files_x86 / "Steam";
+			if (!fs::is_directory(hint_path, error_code)) {
+				Logger::warning("Could not find path for Steam installation on Windows.");
+				return "";
+			}
+		}
+		#pragma warning(pop)
+// Cannot support Android
+// Only FreeBSD currently unofficially supports emulating Linux
+#elif (defined(__linux__) && !defined(__ANDROID__)) || defined(__FreeBSD__)
+		static const fs::path home = std::getenv("HOME");
+		hint_path = home / ".steam" / "steam";
+		if (fs::is_symlink(hint_path, error_code))
+			hint_path = fs::read_symlink(hint_path, error_code);
+		else if (!fs::is_directory(hint_path, error_code)) {
+			hint_path = home / ".local" / "share" / "Steam";
+			if (!fs::is_directory(hint_path, error_code)) {
+#ifdef __FreeBSD__
+				Logger::warning("Could not find path for Steam installation on FreeBSD.");
+#else
+				Logger::warning("Could not find path for Steam installation on Linux.");
+#endif
+				return "";
+			}
+		}
+// Support only Mac, cannot support iOS
+#elif (defined(__APPLE__) && defined(__MACH__)) && TARGET_OS_MAC == 1
+		static const fs::path home = std::getenv("HOME");
+		hint_path = home / "Library" / "Application Support" / "Steam";
+		if (!fs::is_directory(hint_path, error_code)) {
+			Logger::warning("Could not find path for Steam installation on Mac.");
+			return "";
+		}
+// All platforms that reach this point do not seem to even have unofficial Steam support
+#else
+		Logger::warning("Could not find path for Steam installation on unsupported platform.");
+#endif
+	}
+
+	// Could not determine Steam install on platform
+	if (hint_path.empty()) return "";
+
+	// Supplied path was useless, ignore hint_path
+	if (!hint_path_was_empty && !fs::exists(hint_path, error_code))
+		return _search_for_game_path();
+
+	// Steam Library's directory that will contain Victoria 2
+	fs::path vic2_steam_lib_directory;
+	fs::path current_path = hint_path;
+
+	// If hinted path is directory that contains steamapps
+	bool is_steamapps = false;
+	if (fs::is_directory(current_path / steamapps, error_code)) {
+		current_path /= steamapps;
+		is_steamapps = true;
+	}
+
+	// If hinted path is steamapps directory
+	bool is_libraryfolders_vdf = false;
+	if (is_steamapps || (filename_equals(steamapps, current_path) && fs::is_directory(current_path, error_code))) {
+		current_path /= libraryfolders;
+		is_libraryfolders_vdf = true;
+	}
+
+	bool vic2_install_confirmed = false;
+	// if current_path is not a regular file, this is a non-default Steam Library, skip this parser evaluation
+	if (fs::is_regular_file(current_path, error_code) && (is_libraryfolders_vdf || filename_equals(libraryfolders, current_path))) {
+		lexy_vdf::Parser parser;
+
+		std::string buffer;
+		auto error_log_stream = detail::CallbackStream {
+			[](void const* s, std::streamsize n, void* user_data) -> std::streamsize {
+				if (s != nullptr && n > 0 && user_data != nullptr) {
+					static_cast<std::string*>(user_data)->append(static_cast<char const*>(s), n);
+					return n;
+				} else {
+					Logger::warning("Invalid input to parser error log callback: ", s, " / ", n, " / ", user_data);
+					return 0;
+				}
+			},
+			&buffer
+		};
+		parser.set_error_log_to(error_log_stream);
+
+		parser.load_from_file(current_path);
+		if (!parser.parse()) {
+			// Could not find or load libraryfolders.vdf, report error as warning
+			if (!buffer.empty())
+				Logger::warning _(buffer);
+			return "";
+		}
+		std::optional current_node = *(parser.get_key_values());
+
+		// check "libraryfolders" list
+		auto it = current_node.value().find("libraryfolders");
+		if (it == current_node.value().end()) {
+			Logger::warning("Expected libraryfolders.vdf to contain a libraryfolders key.");
+			return "";
+		}
+
+		static constexpr auto visit_node = [](auto&& arg) -> std::optional<lexy_vdf::KeyValues> {
+			using T = std::decay_t<decltype(arg)>;
+			if constexpr (std::is_same_v<T, lexy_vdf::KeyValues>) {
+				return arg;
+			} else {
+				return std::nullopt;
+			}
+		};
+
+		current_node = std::visit(visit_node, it->second);
+
+		if (!current_node.has_value()) {
+			Logger::warning("Expected libraryfolders.vdf's libraryfolders key to be a KeyValue dictionary.");
+			return "";
+		}
+
+		// Array of strings contain "0" to std::to_string(max_amount_of_steam_libraries - 1)
+		static constexpr auto library_indexes = OpenVic::ConstexprIntToStr::make_itosv_array<max_amount_of_steam_libraries>();
+
+		for (const auto& index : library_indexes) {
+			decltype(current_node) node = std::nullopt;
+
+			auto it = current_node.value().find(index);
+			if (it != current_node.value().end()) {
+				node = std::visit(visit_node, it->second);
+			}
+
+			// check "apps" list
+			decltype(node) apps_node = std::nullopt;
+			if (node.has_value()) {
+				it = node.value().find("apps");
+				if (it != node.value().end()) {
+					apps_node = std::visit(visit_node, it->second);
+				}
+			}
+
+			bool lib_contains_victoria_2 = false;
+			if (apps_node.has_value()) {
+				lib_contains_victoria_2 = apps_node.value().find("42960") != node.value().end();
+			}
+
+			if (lib_contains_victoria_2) {
+				it = node.value().find("path");
+				if (it != node.value().end()) {
+					vic2_steam_lib_directory = std::visit(
+						[](auto&& arg) -> std::string_view {
+							using T = std::decay_t<decltype(arg)>;
+							if constexpr (std::is_same_v<T, std::string>) {
+								return arg;
+							} else {
+								return "";
+							}
+						},
+						it->second
+					);
+					vic2_install_confirmed = true;
+					break;
+				}
+			}
+		}
+
+		if (vic2_steam_lib_directory.empty()) {
+			Logger::info("Steam installation appears not to contain Victoria 2.");
+			return "";
+		}
+	}
+
+	// If current_path points to steamapps/libraryfolders.vdf
+	if (vic2_steam_lib_directory.empty()) {
+		if (is_libraryfolders_vdf || filename_equals(libraryfolders, current_path)) {
+			vic2_steam_lib_directory = current_path.parent_path() / vic2_appmanifest;
+		} else if (filename_equals(vic2_appmanifest, current_path)) {
+			vic2_steam_lib_directory = current_path;
+		}
+	}
+
+	// If we could not confirm Victoria 2 was installed via the default Steam installation
+	bool is_common_folder = false;
+	if (!vic2_install_confirmed) {
+		auto parser = lexy_vdf::Parser::from_file(vic2_steam_lib_directory);
+		if (!parser.parse()) {
+			// Could not find or load appmanifest_42960.acf, report error as warning
+			for(auto& error : parser.get_errors()) {
+				Logger::warning(error.message);
+			}
+			return "";
+		}
+
+		// we can pretty much assume the Victoria 2 directory on Steam is valid from here
+		vic2_steam_lib_directory /= common_folder;
+		is_common_folder = true;
+	} else if (fs::is_directory(vic2_steam_lib_directory / steamapps, error_code)) {
+		vic2_steam_lib_directory /= fs::path(steamapps) / common_folder;
+		is_common_folder = true;
+	}
+
+	bool is_Victoria_2_folder = false;
+	if ((is_common_folder || filename_equals(common_folder, vic2_steam_lib_directory)) &&
+		fs::is_directory(vic2_steam_lib_directory, error_code)) {
+		vic2_steam_lib_directory /= Victoria_2_folder;
+		is_Victoria_2_folder = true;
+	}
+	if ((is_Victoria_2_folder || filename_equals(Victoria_2_folder, vic2_steam_lib_directory)) &&
+		fs::is_regular_file(vic2_steam_lib_directory / v2_game_exe, error_code)) {
+		return vic2_steam_lib_directory;
+	}
+
+	// Hail Mary check ignoring the hint_path
+	if (!hint_path_was_empty)
+		return _search_for_game_path();
+
+	Logger::warning("Could not find Victoria 2 game path, this requires manually supplying one.");
+	return ""; // The supplied path fits literally none of the criteria
+}
+
+fs::path Dataloader::search_for_game_path(fs::path hint_path) {
+	auto it = _cached_paths.find(hint_path);
+	if (it != _cached_paths.end())
+		return it->second;
+
+	return _cached_paths[hint_path] = _search_for_game_path(hint_path);
+}
+
 bool Dataloader::set_roots(path_vector_t new_roots) {
 	if (!roots.empty()) {
 		Logger::error("Overriding existing dataloader roots!");
diff --git a/src/openvic-simulation/dataloader/Dataloader.hpp b/src/openvic-simulation/dataloader/Dataloader.hpp
index 9d28132..705da00 100644
--- a/src/openvic-simulation/dataloader/Dataloader.hpp
+++ b/src/openvic-simulation/dataloader/Dataloader.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <filesystem>
+#include <unordered_map>
 
 #include <openvic-dataloader/csv/Parser.hpp>
 #include <openvic-dataloader/v2script/Parser.hpp>
@@ -31,6 +32,25 @@ namespace OpenVic {
 
 		Dataloader() = default;
 
+		/// @brief Searches for the Victoria 2 install directory
+		///
+		/// @param hint_path A path to indicate a hint to assist in searching for the Victoria 2 install directory
+		///	Supports being supplied:
+		///		1. A valid Victoria 2 game directory (Victoria 2 directory that contains a v2game.exe file)
+		///		2. An Empty path: assumes a common Steam install structure per platform.
+		///			2b. If Windows, returns "HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Paradox Interactive\Victoria 2" "path" registry value
+		///			2c. If registry value returns an empty string, performs Steam checks below
+		///		3. A path to a root Steam install. (eg: C:\Program Files(x86)\Steam, ~/.steam/steam)
+		///		4. A path to a root Steam steamapps directory. (eg: C:\Program Files(x86)\Steam\steamapps, ~/.steam/steam/steamapps)
+		///		5. A path to the root Steam libraryfolders.vdf, commonly in the root Steam steamapps directory.
+		///		6. A path to the Steam library directory that contains Victoria 2.
+		///		7. A path to a Steam library's steamapps directory that contains Victoria 2.
+		///		8. A path to a Steam library's steamapps/common directory that contains Victoria 2.
+		///		9. If any of these checks don't resolve to a valid Victoria 2 game directory when supplied a non-empty hint_path, performs empty path behavior.
+		/// @return fs::path The root directory of a valid Victoria 2 install, or an empty path.
+		///
+		static fs::path search_for_game_path(fs::path hint_path = {});
+
 		/* In reverse-load order, so base defines first and final loaded mod last */
 		bool set_roots(path_vector_t new_roots);
 
@@ -55,5 +75,19 @@ namespace OpenVic {
 		/* Args: key, locale, localisation */
 		using localisation_callback_t = NodeTools::callback_t<std::string_view, locale_t, std::string_view>;
 		bool load_localisation_files(localisation_callback_t callback, fs::path const& localisation_dir = "localisation");
+
+	private:
+		struct fshash
+		{
+			size_t operator()(const std::filesystem::path& p) const noexcept {
+				return std::filesystem::hash_value(p);
+			}
+		};
+
+		using hint_path_t = fs::path;
+		using game_path_t = fs::path;
+		inline static std::unordered_map<hint_path_t, game_path_t, fshash> _cached_paths;
 	};
 }
+
+
diff --git a/src/openvic-simulation/dataloader/Dataloader_Windows.hpp b/src/openvic-simulation/dataloader/Dataloader_Windows.hpp
new file mode 100644
index 0000000..f4abbb6
--- /dev/null
+++ b/src/openvic-simulation/dataloader/Dataloader_Windows.hpp
@@ -0,0 +1,162 @@
+#pragma once
+
+#include <concepts>
+#pragma comment(lib, "advapi32.lib")
+
+#include <string>
+#include <string_view>
+
+#include <Windows.h>
+
+namespace OpenVic::Windows {
+	inline std::wstring convert(std::string_view as) {
+		// deal with trivial case of empty string
+		if (as.empty()) return std::wstring();
+
+		// determine required length of new string
+		size_t length = ::MultiByteToWideChar(CP_UTF8, 0, as.data(), (int)as.length(), 0, 0);
+
+		// construct new string of required length
+		std::wstring ret(length, L'\0');
+
+		// convert old string to new string
+		::MultiByteToWideChar(CP_UTF8, 0, as.data(), (int)as.length(), &ret[0], (int)ret.length());
+
+		// return new string ( compiler should optimize this away )
+		return ret;
+	}
+
+	inline std::string convert(std::wstring_view as) {
+		// deal with trivial case of empty string
+		if (as.empty()) return std::string();
+
+		// determine required length of new string
+		size_t length = ::WideCharToMultiByte(CP_UTF8, 0, as.data(), (int)as.length(), 0, 0, NULL, NULL);
+
+		// construct new string of required length
+		std::string ret(length, '\0');
+
+		// convert old string to new string
+		::WideCharToMultiByte(CP_UTF8, 0, as.data(), (int)as.length(), &ret[0], (int)ret.length(), NULL, NULL);
+
+		// return new string ( compiler should optimize this away )
+		return ret;
+	}
+
+	template<typename T, typename... U>
+	concept any_of = (std::same_as<T, U> || ...);
+
+	template<typename T>
+	concept either_char_type = any_of<T, char, wchar_t>;
+
+	template<typename T>
+	concept has_data = requires(T t) {
+		{ t.data() } -> std::convertible_to<const typename T::value_type*>;
+	};
+
+	class RegistryKey {
+	public:
+		RegistryKey(HKEY key_handle)
+			: _key_handle(key_handle) {
+		}
+
+		template<either_char_type CHAR_T, either_char_type CHAR_T2>
+		RegistryKey(HKEY parent_key_handle, std::basic_string_view<CHAR_T> child_key_name, std::basic_string_view<CHAR_T2> value_name) {
+			open_key(parent_key_handle, child_key_name);
+			query_key(value_name);
+		}
+
+		~RegistryKey() {
+			close_key();
+		}
+
+		bool is_open() const {
+			return _key_handle != nullptr;
+		}
+
+		std::wstring_view value() const {
+			return _value;
+		}
+
+		template<either_char_type CHAR_T>
+		LSTATUS open_key(HKEY parent_key_handle, std::basic_string_view<CHAR_T> key_path) {
+			if (is_open())
+				close_key();
+			if constexpr (std::is_same_v<CHAR_T, char>)
+				return RegOpenKeyExW(parent_key_handle, convert(key_path).data(), REG_NONE, KEY_READ, &_key_handle);
+			else
+				return RegOpenKeyExW(parent_key_handle, key_path.data(), REG_NONE, KEY_READ, &_key_handle);
+		}
+
+		bool is_predefined() const {
+			return (_key_handle == HKEY_CURRENT_USER) ||
+				   (_key_handle == HKEY_LOCAL_MACHINE) ||
+				   (_key_handle == HKEY_CLASSES_ROOT) ||
+				   (_key_handle == HKEY_CURRENT_CONFIG) ||
+				   (_key_handle == HKEY_CURRENT_USER_LOCAL_SETTINGS) ||
+				   (_key_handle == HKEY_PERFORMANCE_DATA) ||
+				   (_key_handle == HKEY_PERFORMANCE_NLSTEXT) ||
+				   (_key_handle == HKEY_PERFORMANCE_TEXT) ||
+				   (_key_handle == HKEY_USERS);
+		}
+
+		LSTATUS close_key() {
+			if (!is_open() || is_predefined())
+				return ERROR_SUCCESS;
+			auto result = RegCloseKey(_key_handle);
+			_key_handle = nullptr;
+			return result;
+		}
+
+		template<either_char_type CHAR_T>
+		LSTATUS query_key(std::basic_string_view<CHAR_T> value_name) {
+			DWORD data_size;
+			DWORD type;
+
+			const auto& wide_value = [&value_name]() -> has_data auto {
+				if constexpr (std::is_same_v<CHAR_T, char>) {
+					return convert(value_name);
+				} else {
+					return value_name;
+				}
+			}();
+
+			auto result = RegQueryValueExW(_key_handle, wide_value.data(), NULL, &type, NULL, &data_size);
+			if (result != ERROR_SUCCESS || type != REG_SZ) {
+				close_key();
+				return result;
+			}
+			_value = std::wstring(data_size / sizeof(wchar_t), L'\0');
+			result = RegQueryValueExW(_key_handle, wide_value.data(), NULL, NULL, reinterpret_cast<LPBYTE>(_value.data()), &data_size);
+			close_key();
+
+			std::size_t first_null = _value.find_first_of(L'\0');
+			if (first_null != std::string::npos)
+				_value.resize(first_null);
+
+			return result;
+		}
+
+	private:
+		HKEY _key_handle = nullptr;
+		std::wstring _value;
+	};
+
+	template<either_char_type RCHAR_T, either_char_type CHAR_T, either_char_type CHAR_T2>
+	std::basic_string<RCHAR_T> ReadRegValue(HKEY root, std::basic_string_view<CHAR_T> key, std::basic_string_view<CHAR_T2> name) {
+		RegistryKey registry_key(root, key, name);
+		if constexpr (std::is_same_v<RCHAR_T, char>) {
+			return convert(registry_key.value());
+		} else {
+			return registry_key.value();
+		}
+	}
+
+	template<either_char_type RCHAR_T, either_char_type CHAR_T, either_char_type CHAR_T2>
+	std::basic_string<RCHAR_T> ReadRegValue(HKEY root, const CHAR_T* key, const CHAR_T2* name) {
+		auto key_sv = std::basic_string_view(key);
+		auto name_sv = std::basic_string_view(name);
+
+		return ReadRegValue<RCHAR_T>(root, key_sv, name_sv);
+	}
+}
\ No newline at end of file
diff --git a/src/openvic-simulation/utility/ConstexprIntToStr.hpp b/src/openvic-simulation/utility/ConstexprIntToStr.hpp
new file mode 100644
index 0000000..e383365
--- /dev/null
+++ b/src/openvic-simulation/utility/ConstexprIntToStr.hpp
@@ -0,0 +1,56 @@
+#pragma once
+
+#include <array>
+#include <cstddef>
+#include <string_view>
+#include <utility>
+
+namespace OpenVic::ConstexprIntToStr {
+	template<class T, T... values1, T... values2>
+	constexpr decltype(auto) append_sequence(std::integer_sequence<T, values1...>, std::integer_sequence<T, values2...>) {
+		return std::integer_sequence<T, values1..., values2...> {};
+	}
+
+	template<class sequence_t>
+	struct string_sequence_to_view;
+
+	template<char... chars>
+	struct string_sequence_to_view<std::integer_sequence<char, chars...>> {
+		static constexpr decltype(auto) get() {
+			return std::string_view { c_str };
+		}
+
+		static constexpr const char c_str[] { chars..., char {} };
+	};
+
+	template<std::size_t value>
+	constexpr decltype(auto) integer_to_string_sequence() {
+		constexpr auto digits = []() {
+			return "0123456789abcdefghijklmnopqrstuvwxyz";
+		};
+
+		constexpr std::size_t remainder = value % 10;
+		constexpr std::size_t next_value = value / 10;
+
+		if constexpr (next_value != 0) {
+			return append_sequence(integer_to_string_sequence<next_value>(), std::integer_sequence<char, digits()[remainder]> {});
+		} else {
+			return std::integer_sequence<char, digits()[remainder]> {};
+		}
+	}
+	template<std::size_t i>
+	constexpr std::string_view make_string() {
+		return string_sequence_to_view<decltype(integer_to_string_sequence<i>())> {}.c_str;
+	}
+
+	template<std::size_t... ManyIntegers>
+	constexpr auto generate_itosv_array(std::integer_sequence<std::size_t, ManyIntegers...>) {
+		return std::array<std::string_view, sizeof...(ManyIntegers)> { make_string<ManyIntegers>()... };
+	}
+
+	// Make array of N string views, countings up from 0 to N - 1
+	template<std::size_t N>
+	constexpr auto make_itosv_array() {
+		return generate_itosv_array(std::make_integer_sequence<std::size_t, N>());
+	}
+}
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