text: // sol3
  
  // The MIT License (MIT)
  
  // Copyright (c) 2013-2020 Rapptz, ThePhD and contributors
  
  // Permission is hereby granted, free of charge, to any person obtaining a copy of
  // this software and associated documentation files (the "Software"), to deal in
  // the Software without restriction, including without limitation the rights to
  // use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
  // the Software, and to permit persons to whom the Software is furnished to do so,
  // subject to the following conditions:
  
  // The above copyright notice and this permission notice shall be included in all
  // copies or substantial portions of the Software.
  
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  // FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  // COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  // IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  
  #ifndef SOL_STACK_HPP
  #define SOL_STACK_HPP
  
  #include <sol/trampoline.hpp>
  #include <sol/stack_core.hpp>
  #include <sol/stack_reference.hpp>
  #include <sol/stack_check.hpp>
  #include <sol/stack_get.hpp>
  #include <sol/stack_check_get.hpp>
  #include <sol/stack_push.hpp>
  #include <sol/stack_pop.hpp>
  #include <sol/stack_field.hpp>
  #include <sol/stack_probe.hpp>
  
  #include <cstring>
  #include <array>
  
  namespace sol {
  	namespace detail {
  		using typical_chunk_name_t = char[SOL_ID_SIZE_I_];
  		using typical_file_chunk_name_t = char[SOL_FILE_ID_SIZE_I_];
  
  		inline const std::string& default_chunk_name() {
  			static const std::string name = "";
  			return name;
  		}
  
  		template <std::size_t N>
  		const char* make_chunk_name(const string_view& code, const std::string& chunkname, char (&basechunkname)[N]) {
  			if (chunkname.empty()) {
  				auto it = code.cbegin();
  				auto e = code.cend();
  				std::size_t i = 0;
  				static const std::size_t n = N - 4;
  				for (i = 0; i < n && it != e; ++i, ++it) {
  					basechunkname[i] = *it;
  				}
  				if (it != e) {
  					for (std::size_t c = 0; c < 3; ++i, ++c) {
  						basechunkname[i] = '.';
  					}
  				}
  				basechunkname[i] = '\0';
  				return &basechunkname[0];
  			}
  			else {
  				return chunkname.c_str();
  			}
  		}
  
  		inline void clear_entries(stack_reference r) {
  			stack::push(r.lua_state(), lua_nil);
  			while (lua_next(r.lua_state(), -2)) {
  				absolute_index key(r.lua_state(), -2);
  				auto pn = stack::pop_n(r.lua_state(), 1);
  				stack::set_field<false, true>(r.lua_state(), key, lua_nil, r.stack_index());
  			}
  		}
  
  		inline void clear_entries(const reference& registry_reference) {
  			auto pp = stack::push_pop(registry_reference);
  			stack_reference ref(registry_reference.lua_state(), -1);
  			clear_entries(ref);
  		}
  	} // namespace detail
  
  	namespace stack {
  		namespace stack_detail {
  			template <typename T>
  			inline int push_as_upvalues(lua_State* L, T& item) {
  				typedef std::decay_t<T> TValue;
  				static const std::size_t itemsize = sizeof(TValue);
  				static const std::size_t voidsize = sizeof(void*);
  				static const std::size_t voidsizem1 = voidsize - 1;
  				static const std::size_t data_t_count = (sizeof(TValue) + voidsizem1) / voidsize;
  				typedef std::array<void*, data_t_count> data_t;
  
  				data_t data { {} };
  				std::memcpy(&data[0], std::addressof(item), itemsize);
  				int pushcount = 0;
  				for (const auto& v : data) {
  					lua_pushlightuserdata(L, v);
  					pushcount += 1;
  				}
  				return pushcount;
  			}
  
  			template <typename T>
  			inline std::pair<T, int> get_as_upvalues(lua_State* L, int index = 2) {
  				static const std::size_t data_t_count = (sizeof(T) + (sizeof(void*) - 1)) / sizeof(void*);
  				typedef std::array<void*, data_t_count> data_t;
  				data_t voiddata { {} };
  				for (std::size_t i = 0, d = 0; d < sizeof(T); ++i, d += sizeof(void*)) {
  					voiddata[i] = lua_touserdata(L, upvalue_index(index++));
  				}
  				return std::pair<T, int>(*reinterpret_cast<T*>(static_cast<void*>(voiddata.data())), index);
  			}
  
  			template <typename T>
  			inline std::pair<T, int> get_as_upvalues_using_function(lua_State* L, int function_index = -1) {
  				static const std::size_t data_t_count = (sizeof(T) + (sizeof(void*) - 1)) / sizeof(void*);
  				typedef std::array<void*, data_t_count> data_t;
  				function_index = lua_absindex(L, function_index);
  				int index = 0;
  				data_t voiddata { {} };
  				for (std::size_t d = 0; d < sizeof(T); d += sizeof(void*)) {
  					// first upvalue is nullptr to respect environment shenanigans
  					// So +2 instead of +1
  					const char* upvalue_name = lua_getupvalue(L, function_index, index + 2);
  					if (upvalue_name == nullptr) {
  						// We should freak out here...
  						break;
  					}
  					voiddata[index] = lua_touserdata(L, -1);
  					++index;
  				}
  				lua_pop(L, index);
  				return std::pair<T, int>(*reinterpret_cast<T*>(static_cast<void*>(voiddata.data())), index);
  			}
  
  			template <bool checked, typename Handler, typename Fx, typename... Args>
  			static decltype(auto) eval(types<>, std::index_sequence<>, lua_State*, int, Handler&&, record&, Fx&& fx, Args&&... args) {
  				return std::forward<Fx>(fx)(std::forward<Args>(args)...);
  			}
  
  			template <bool checked, typename Arg, typename... Args, std::size_t I, std::size_t... Is, typename Handler, typename Fx, typename... FxArgs>
  			static decltype(auto) eval(types<Arg, Args...>, std::index_sequence<I, Is...>, lua_State* L_, int start_index_, Handler&& handler_, record& tracking_, Fx&& fx_, FxArgs&&... fxargs_) {
  #if SOL_IS_ON(SOL_PROPAGATE_EXCEPTIONS_I_)
  				// We can save performance/time by letting errors unwind produced arguments
  				// rather than checking everything once, and then potentially re-doing work
  				if constexpr (checked) {
  					return eval<checked>(types<Args...>(),
  					     std::index_sequence<Is...>(),
  					     L_,
  					     start_index_,
  					     std::forward<Handler>(handler_),
  					     tracking_,
  					     std::forward<Fx>(fx_),
  					     std::forward<FxArgs>(fxargs_)...,
  					     *stack_detail::check_get_arg<Arg>(L_, start_index_ + tracking_.used, handler_, tracking_));
  				}
  				else
  #endif
  				{
  					return eval<checked>(types<Args...>(),
  					     std::index_sequence<Is...>(),
  					     L_,
  					     start_index_,
  					     std::forward<Handler>(handler_),
  					     tracking_,
  					     std::forward<Fx>(fx_),
  					     std::forward<FxArgs>(fxargs_)...,
  					     stack_detail::unchecked_get_arg<Arg>(L_, start_index_ + tracking_.used, tracking_));
  				}
  			}
  
  			template <bool checkargs = detail::default_safe_function_calls, std::size_t... I, typename R, typename... Args, typename Fx, typename... FxArgs>
  			inline decltype(auto) call(types<R>, types<Args...> argument_types_, std::index_sequence<I...> argument_indices_, lua_State* L_, int start_index_, Fx&& fx_, FxArgs&&... args_) {
  				static_assert(meta::all_v<meta::is_not_move_only<Args>...>,
  				     "One of the arguments being bound is a move-only type, and it is not being taken by reference: this will break your code. Please take "
  				     "a reference and std::move it manually if this was your intention.");
  				argument_handler<types<R, Args...>> handler {};
  				record tracking {};
  #if SOL_IS_OFF(SOL_PROPAGATE_EXCEPTIONS_I_)
  				if constexpr (checkargs) {
  					multi_check<Args...>(L_, start_index_, handler);
  				}
  #endif
  				if constexpr (std::is_void_v<R>) {
  					eval<checkargs>(argument_types_, argument_indices_, L_, start_index_, handler, tracking, std::forward<Fx>(fx_), std::forward<FxArgs>(args_)...);
  				}
  				else {
  					return eval<checkargs>(argument_types_, argument_indices_, L_, start_index_, handler, tracking, std::forward<Fx>(fx_), std::forward<FxArgs>(args_)...);
  				}
  			}
  		} // namespace stack_detail
  
  		template <typename T>
  		int set_ref(lua_State* L, T&& arg, int tableindex = -2) {
  			push(L, std::forward<T>(arg));
  			return luaL_ref(L, tableindex);
  		}
  
  		template <bool check_args = detail::default_safe_function_calls, typename R, typename... Args, typename Fx, typename... FxArgs>
  		inline decltype(auto) call(types<R> tr, types<Args...> ta, lua_State* L, int start, Fx&& fx, FxArgs&&... args) {
  			using args_indices = std::make_index_sequence<sizeof...(Args)>;
  			if constexpr (std::is_void_v<R>) {
  				stack_detail::call<check_args>(tr, ta, args_indices(), L, start, std::forward<Fx>(fx), std::forward<FxArgs>(args)...);
  			}
  			else {
  				return stack_detail::call<check_args>(tr, ta, args_indices(), L, start, std::forward<Fx>(fx), std::forward<FxArgs>(args)...);
  			}
  		}
  
  		template <bool check_args = detail::default_safe_function_calls, typename R, typename... Args, typename Fx, typename... FxArgs>
  		inline decltype(auto) call(types<R> tr, types<Args...> ta, lua_State* L, Fx&& fx, FxArgs&&... args) {
  			if constexpr (std::is_void_v<R>) {
  				call<check_args>(tr, ta, L, 1, std::forward<Fx>(fx), std::forward<FxArgs>(args)...);
  			}
  			else {
  				return call<check_args>(tr, ta, L, 1, std::forward<Fx>(fx), std::forward<FxArgs>(args)...);
  			}
  		}
  
  		template <bool check_args = detail::default_safe_function_calls, typename R, typename... Args, typename Fx, typename... FxArgs>
  		inline decltype(auto) call_from_top(types<R> tr, types<Args...> ta, lua_State* L, Fx&& fx, FxArgs&&... args) {
  			using expected_count_t = meta::count_for_pack<lua_size, Args...>;
  			if constexpr (std::is_void_v<R>) {
  				call<check_args>(tr,
  				     ta,
  				     L,
  				     (std::max)(static_cast<int>(lua_gettop(L) - expected_count_t::value), static_cast<int>(0)),
  				     std::forward<Fx>(fx),
  				     std::forward<FxArgs>(args)...);
  			}
  			else {
  				return call<check_args>(tr,
  				     ta,
  				     L,
  				     (std::max)(static_cast<int>(lua_gettop(L) - expected_count_t::value), static_cast<int>(0)),
  				     std::forward<Fx>(fx),
  				     std::forward<FxArgs>(args)...);
  			}
  		}
  
  		template <bool check_args = detail::default_safe_function_calls, bool clean_stack = true, typename Ret0, typename... Ret, typename... Args,
  		     typename Fx, typename... FxArgs>
  		inline int call_into_lua(types<Ret0, Ret...> tr, types<Args...> ta, lua_State* L, int start, Fx&& fx, FxArgs&&... fxargs) {
  			if constexpr (std::is_void_v<Ret0>) {
  				call<check_args>(tr, ta, L, start, std::forward<Fx>(fx), std::forward<FxArgs>(fxargs)...);
  				if constexpr (clean_stack) {
  					lua_settop(L, 0);
  				}
  				return 0;
  			}
  			else {
  				(void)tr;
  				decltype(auto) r
  				     = call<check_args>(types<meta::return_type_t<Ret0, Ret...>>(), ta, L, start, std::forward<Fx>(fx), std::forward<FxArgs>(fxargs)...);
  				using R = meta::unqualified_t<decltype(r)>;
  				using is_stack = meta::any<is_stack_based<R>, std::is_same<R, absolute_index>, std::is_same<R, ref_index>, std::is_same<R, raw_index>>;
  				if constexpr (clean_stack && !is_stack::value) {
  					lua_settop(L, 0);
  				}
  				return push_reference(L, std::forward<decltype(r)>(r));
  			}
  		}
  
  		template <bool check_args = detail::default_safe_function_calls, bool clean_stack = true, typename Fx, typename... FxArgs>
  		inline int call_lua(lua_State* L, int start, Fx&& fx, FxArgs&&... fxargs) {
  			using traits_type = lua_bind_traits<meta::unqualified_t<Fx>>;
  			using args_list = typename traits_type::args_list;
  			using returns_list = typename traits_type::returns_list;
  			return call_into_lua<check_args, clean_stack>(returns_list(), args_list(), L, start, std::forward<Fx>(fx), std::forward<FxArgs>(fxargs)...);
  		}
  
  		inline call_syntax get_call_syntax(lua_State* L, const string_view& key, int index) {
  			if (lua_gettop(L) < 1) {
  				return call_syntax::dot;
  			}
  			luaL_getmetatable(L, key.data());
  			auto pn = pop_n(L, 1);
  			if (lua_compare(L, -1, index, LUA_OPEQ) != 1) {
  				return call_syntax::dot;
  			}
  			return call_syntax::colon;
  		}
  
  		inline void script(
  		     lua_State* L, lua_Reader reader, void* data, const std::string& chunkname = detail::default_chunk_name(), load_mode mode = load_mode::any) {
  			detail::typical_chunk_name_t basechunkname = {};
  			const char* chunknametarget = detail::make_chunk_name("lua_Reader", chunkname, basechunkname);
  			if (lua_load(L, reader, data, chunknametarget, to_string(mode).c_str()) || lua_pcall(L, 0, LUA_MULTRET, 0)) {
  				lua_error(L);
  			}
  		}
  
  		inline void script(
  		     lua_State* L, const string_view& code, const std::string& chunkname = detail::default_chunk_name(), load_mode mode = load_mode::any) {
  
  			detail::typical_chunk_name_t basechunkname = {};
  			const char* chunknametarget = detail::make_chunk_name(code, chunkname, basechunkname);
  			if (luaL_loadbufferx(L, code.data(), code.size(), chunknametarget, to_string(mode).c_str()) || lua_pcall(L, 0, LUA_MULTRET, 0)) {
  				lua_error(L);
  			}
  		}
  
  		inline void script_file(lua_State* L, const std::string& filename, load_mode mode = load_mode::any) {
  			if (luaL_loadfilex(L, filename.c_str(), to_string(mode).c_str()) || lua_pcall(L, 0, LUA_MULTRET, 0)) {
  				lua_error(L);
  			}
  		}
  
  		inline void luajit_exception_handler(lua_State* L, int (*handler)(lua_State*, lua_CFunction) = detail::c_trampoline) {
  #if SOL_IS_ON(SOL_USE_LUAJIT_EXCEPTION_TRAMPOLINE_I_)
  			if (L == nullptr) {
  				return;
  			}
  #if SOL_IS_ON(SOL_SAFE_STACK_CHECK_I_)
  			luaL_checkstack(L, 1, detail::not_enough_stack_space_generic);
  #endif // make sure stack doesn't overflow
  			lua_pushlightuserdata(L, (void*)handler);
  			auto pn = pop_n(L, 1);
  			luaJIT_setmode(L, -1, LUAJIT_MODE_WRAPCFUNC | LUAJIT_MODE_ON);
  #else
  			(void)L;
  			(void)handler;
  #endif
  		}
  
  		inline void luajit_exception_off(lua_State* L) {
  #if SOL_IS_ON(SOL_USE_LUAJIT_EXCEPTION_TRAMPOLINE_I_)
  			if (L == nullptr) {
  				return;
  			}
  			luaJIT_setmode(L, -1, LUAJIT_MODE_WRAPCFUNC | LUAJIT_MODE_OFF);
  #else
  			(void)L;
  #endif
  		}
  	} // namespace stack
  } // namespace sol
  
  #endif // SOL_STACK_HPP
  