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authorEike Ziller <eike.ziller@qt.io>2017-12-19 14:49:09 +0100
committerEike Ziller <eike.ziller@qt.io>2017-12-21 06:37:07 +0000
commitf9177d4b6c509054a5dfe10cb0e103f48a39a939 (patch)
tree65ccb92ed55445c94b2c1293349f21c53daae2bf /src/libs/3rdparty/variant/variant.hpp
parentb2a16190e8e53815ef81c248b96dbe55434d7fb5 (diff)
Add implementation of std::variant
Type-safe unions for C++. Change-Id: I3c1eb89a240a11d27b07acae588a924a0618173e Reviewed-by: hjk <hjk@qt.io>
Diffstat (limited to 'src/libs/3rdparty/variant/variant.hpp')
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1 files changed, 2457 insertions, 0 deletions
diff --git a/src/libs/3rdparty/variant/variant.hpp b/src/libs/3rdparty/variant/variant.hpp
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+// MPark.Variant
+//
+// Copyright Michael Park, 2015-2017
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#ifndef MPARK_VARIANT_HPP
+#define MPARK_VARIANT_HPP
+
+/*
+ variant synopsis
+
+namespace std {
+
+ // 20.7.2, class template variant
+ template <class... Types>
+ class variant {
+ public:
+
+ // 20.7.2.1, constructors
+ constexpr variant() noexcept(see below);
+ variant(const variant&);
+ variant(variant&&) noexcept(see below);
+
+ template <class T> constexpr variant(T&&) noexcept(see below);
+
+ template <class T, class... Args>
+ constexpr explicit variant(in_place_type_t<T>, Args&&...);
+
+ template <class T, class U, class... Args>
+ constexpr explicit variant(
+ in_place_type_t<T>, initializer_list<U>, Args&&...);
+
+ template <size_t I, class... Args>
+ constexpr explicit variant(in_place_index_t<I>, Args&&...);
+
+ template <size_t I, class U, class... Args>
+ constexpr explicit variant(
+ in_place_index_t<I>, initializer_list<U>, Args&&...);
+
+ // 20.7.2.2, destructor
+ ~variant();
+
+ // 20.7.2.3, assignment
+ variant& operator=(const variant&);
+ variant& operator=(variant&&) noexcept(see below);
+
+ template <class T> variant& operator=(T&&) noexcept(see below);
+
+ // 20.7.2.4, modifiers
+ template <class T, class... Args>
+ T& emplace(Args&&...);
+
+ template <class T, class U, class... Args>
+ T& emplace(initializer_list<U>, Args&&...);
+
+ template <size_t I, class... Args>
+ variant_alternative<I, variant>& emplace(Args&&...);
+
+ template <size_t I, class U, class... Args>
+ variant_alternative<I, variant>& emplace(initializer_list<U>, Args&&...);
+
+ // 20.7.2.5, value status
+ constexpr bool valueless_by_exception() const noexcept;
+ constexpr size_t index() const noexcept;
+
+ // 20.7.2.6, swap
+ void swap(variant&) noexcept(see below);
+ };
+
+ // 20.7.3, variant helper classes
+ template <class T> struct variant_size; // undefined
+
+ template <class T>
+ constexpr size_t variant_size_v = variant_size<T>::value;
+
+ template <class T> struct variant_size<const T>;
+ template <class T> struct variant_size<volatile T>;
+ template <class T> struct variant_size<const volatile T>;
+
+ template <class... Types>
+ struct variant_size<variant<Types...>>;
+
+ template <size_t I, class T> struct variant_alternative; // undefined
+
+ template <size_t I, class T>
+ using variant_alternative_t = typename variant_alternative<I, T>::type;
+
+ template <size_t I, class T> struct variant_alternative<I, const T>;
+ template <size_t I, class T> struct variant_alternative<I, volatile T>;
+ template <size_t I, class T> struct variant_alternative<I, const volatile T>;
+
+ template <size_t I, class... Types>
+ struct variant_alternative<I, variant<Types...>>;
+
+ constexpr size_t variant_npos = -1;
+
+ // 20.7.4, value access
+ template <class T, class... Types>
+ constexpr bool holds_alternative(const variant<Types...>&) noexcept;
+
+ template <size_t I, class... Types>
+ constexpr variant_alternative_t<I, variant<Types...>>&
+ get(variant<Types...>&);
+
+ template <size_t I, class... Types>
+ constexpr variant_alternative_t<I, variant<Types...>>&&
+ get(variant<Types...>&&);
+
+ template <size_t I, class... Types>
+ constexpr variant_alternative_t<I, variant<Types...>> const&
+ get(const variant<Types...>&);
+
+ template <size_t I, class... Types>
+ constexpr variant_alternative_t<I, variant<Types...>> const&&
+ get(const variant<Types...>&&);
+
+ template <class T, class... Types>
+ constexpr T& get(variant<Types...>&);
+
+ template <class T, class... Types>
+ constexpr T&& get(variant<Types...>&&);
+
+ template <class T, class... Types>
+ constexpr const T& get(const variant<Types...>&);
+
+ template <class T, class... Types>
+ constexpr const T&& get(const variant<Types...>&&);
+
+ template <size_t I, class... Types>
+ constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>
+ get_if(variant<Types...>*) noexcept;
+
+ template <size_t I, class... Types>
+ constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>
+ get_if(const variant<Types...>*) noexcept;
+
+ template <class T, class... Types>
+ constexpr add_pointer_t<T>
+ get_if(variant<Types...>*) noexcept;
+
+ template <class T, class... Types>
+ constexpr add_pointer_t<const T>
+ get_if(const variant<Types...>*) noexcept;
+
+ // 20.7.5, relational operators
+ template <class... Types>
+ constexpr bool operator==(const variant<Types...>&, const variant<Types...>&);
+
+ template <class... Types>
+ constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&);
+
+ template <class... Types>
+ constexpr bool operator<(const variant<Types...>&, const variant<Types...>&);
+
+ template <class... Types>
+ constexpr bool operator>(const variant<Types...>&, const variant<Types...>&);
+
+ template <class... Types>
+ constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&);
+
+ template <class... Types>
+ constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&);
+
+ // 20.7.6, visitation
+ template <class Visitor, class... Variants>
+ constexpr see below visit(Visitor&&, Variants&&...);
+
+ // 20.7.7, class monostate
+ struct monostate;
+
+ // 20.7.8, monostate relational operators
+ constexpr bool operator<(monostate, monostate) noexcept;
+ constexpr bool operator>(monostate, monostate) noexcept;
+ constexpr bool operator<=(monostate, monostate) noexcept;
+ constexpr bool operator>=(monostate, monostate) noexcept;
+ constexpr bool operator==(monostate, monostate) noexcept;
+ constexpr bool operator!=(monostate, monostate) noexcept;
+
+ // 20.7.9, specialized algorithms
+ template <class... Types>
+ void swap(variant<Types...>&, variant<Types...>&) noexcept(see below);
+
+ // 20.7.10, class bad_variant_access
+ class bad_variant_access;
+
+ // 20.7.11, hash support
+ template <class T> struct hash;
+ template <class... Types> struct hash<variant<Types...>>;
+ template <> struct hash<monostate>;
+
+} // namespace std
+
+*/
+
+#include <cstddef>
+#include <exception>
+#include <functional>
+#include <initializer_list>
+#include <new>
+#include <type_traits>
+#include <utility>
+
+// MPark.Variant
+//
+// Copyright Michael Park, 2015-2017
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#ifndef MPARK_CONFIG_HPP
+#define MPARK_CONFIG_HPP
+
+// MSVC 2015 Update 3.
+#if __cplusplus < 201103L && (!defined(_MSC_VER) || _MSC_FULL_VER < 190024210)
+#error "MPark.Variant requires C++11 support."
+#endif
+
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
+#ifndef __has_include
+#define __has_include(x) 0
+#endif
+
+#ifndef __has_feature
+#define __has_feature(x) 0
+#endif
+
+#if __has_builtin(__builtin_addressof) || \
+ (defined(__GNUC__) && __GNUC__ >= 7) || defined(_MSC_VER)
+#define MPARK_BUILTIN_ADDRESSOF
+#endif
+
+#if __has_builtin(__builtin_unreachable)
+#define MPARK_BUILTIN_UNREACHABLE
+#endif
+
+#if __has_builtin(__type_pack_element)
+#define MPARK_TYPE_PACK_ELEMENT
+#endif
+
+#if defined(__cpp_constexpr) && __cpp_constexpr >= 201304
+#define MPARK_CPP14_CONSTEXPR
+#endif
+
+#if __has_feature(cxx_exceptions) || defined(__cpp_exceptions) || \
+ (defined(_MSC_VER) && defined(_CPPUNWIND))
+#define MPARK_EXCEPTIONS
+#endif
+
+#if defined(__cpp_generic_lambdas) || defined(_MSC_VER)
+#define MPARK_GENERIC_LAMBDAS
+#endif
+
+#if defined(__cpp_lib_integer_sequence)
+#define MPARK_INTEGER_SEQUENCE
+#endif
+
+#if defined(__cpp_return_type_deduction) || defined(_MSC_VER)
+#define MPARK_RETURN_TYPE_DEDUCTION
+#endif
+
+#if defined(__cpp_lib_transparent_operators) || defined(_MSC_VER)
+#define MPARK_TRANSPARENT_OPERATORS
+#endif
+
+#if defined(__cpp_variable_templates) || defined(_MSC_VER)
+#define MPARK_VARIABLE_TEMPLATES
+#endif
+
+#if !defined(__GLIBCXX__) || __has_include(<codecvt>) // >= libstdc++-5
+#define MPARK_TRIVIALITY_TYPE_TRAITS
+#endif
+
+#endif // MPARK_CONFIG_HPP
+
+// MPark.Variant
+//
+// Copyright Michael Park, 2015-2017
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#ifndef MPARK_IN_PLACE_HPP
+#define MPARK_IN_PLACE_HPP
+
+#include <cstddef>
+
+
+namespace mpark {
+
+ struct in_place_t { explicit in_place_t() = default; };
+
+ template <std::size_t I>
+ struct in_place_index_t { explicit in_place_index_t() = default; };
+
+ template <typename T>
+ struct in_place_type_t { explicit in_place_type_t() = default; };
+
+#ifdef MPARK_VARIABLE_TEMPLATES
+ constexpr in_place_t in_place{};
+
+ template <std::size_t I> constexpr in_place_index_t<I> in_place_index{};
+
+ template <typename T> constexpr in_place_type_t<T> in_place_type{};
+#endif
+
+} // namespace mpark
+
+#endif // MPARK_IN_PLACE_HPP
+
+// MPark.Variant
+//
+// Copyright Michael Park, 2015-2017
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#ifndef MPARK_LIB_HPP
+#define MPARK_LIB_HPP
+
+#include <memory>
+#include <functional>
+#include <type_traits>
+#include <utility>
+
+
+#define RETURN(...) \
+ noexcept(noexcept(__VA_ARGS__)) -> decltype(__VA_ARGS__) { \
+ return __VA_ARGS__; \
+ }
+
+namespace mpark {
+ namespace lib {
+ template <typename T>
+ struct identity { using type = T; };
+
+ inline namespace cpp14 {
+ template <typename T, std::size_t N>
+ struct array {
+ constexpr const T &operator[](std::size_t index) const {
+ return data[index];
+ }
+
+ T data[N == 0 ? 1 : N];
+ };
+
+ template <typename T>
+ using add_pointer_t = typename std::add_pointer<T>::type;
+
+ template <typename... Ts>
+ using common_type_t = typename std::common_type<Ts...>::type;
+
+ template <typename T>
+ using decay_t = typename std::decay<T>::type;
+
+ template <bool B, typename T = void>
+ using enable_if_t = typename std::enable_if<B, T>::type;
+
+ template <typename T>
+ using remove_const_t = typename std::remove_const<T>::type;
+
+ template <typename T>
+ using remove_reference_t = typename std::remove_reference<T>::type;
+
+ template <typename T>
+ inline constexpr T &&forward(remove_reference_t<T> &t) noexcept {
+ return static_cast<T &&>(t);
+ }
+
+ template <typename T>
+ inline constexpr T &&forward(remove_reference_t<T> &&t) noexcept {
+ static_assert(!std::is_lvalue_reference<T>::value,
+ "can not forward an rvalue as an lvalue");
+ return static_cast<T &&>(t);
+ }
+
+ template <typename T>
+ inline constexpr remove_reference_t<T> &&move(T &&t) noexcept {
+ return static_cast<remove_reference_t<T> &&>(t);
+ }
+
+#ifdef MPARK_INTEGER_SEQUENCE
+ using std::integer_sequence;
+ using std::index_sequence;
+ using std::make_index_sequence;
+ using std::index_sequence_for;
+#else
+ template <typename T, T... Is>
+ struct integer_sequence {
+ using value_type = T;
+ static constexpr std::size_t size() noexcept { return sizeof...(Is); }
+ };
+
+ template <std::size_t... Is>
+ using index_sequence = integer_sequence<std::size_t, Is...>;
+
+ template <typename Lhs, typename Rhs>
+ struct make_index_sequence_concat;
+
+ template <std::size_t... Lhs, std::size_t... Rhs>
+ struct make_index_sequence_concat<index_sequence<Lhs...>,
+ index_sequence<Rhs...>>
+ : identity<index_sequence<Lhs..., (sizeof...(Lhs) + Rhs)...>> {};
+
+ template <std::size_t N>
+ struct make_index_sequence_impl;
+
+ template <std::size_t N>
+ using make_index_sequence = typename make_index_sequence_impl<N>::type;
+
+ template <std::size_t N>
+ struct make_index_sequence_impl
+ : make_index_sequence_concat<make_index_sequence<N / 2>,
+ make_index_sequence<N - (N / 2)>> {};
+
+ template <>
+ struct make_index_sequence_impl<0> : identity<index_sequence<>> {};
+
+ template <>
+ struct make_index_sequence_impl<1> : identity<index_sequence<0>> {};
+
+ template <typename... Ts>
+ using index_sequence_for = make_index_sequence<sizeof...(Ts)>;
+#endif
+
+ // <functional>
+#ifdef MPARK_TRANSPARENT_OPERATORS
+ using equal_to = std::equal_to<>;
+#else
+ struct equal_to {
+ template <typename Lhs, typename Rhs>
+ inline constexpr auto operator()(Lhs &&lhs, Rhs &&rhs) const
+ RETURN(lib::forward<Lhs>(lhs) == lib::forward<Rhs>(rhs))
+ };
+#endif
+
+#ifdef MPARK_TRANSPARENT_OPERATORS
+ using not_equal_to = std::not_equal_to<>;
+#else
+ struct not_equal_to {
+ template <typename Lhs, typename Rhs>
+ inline constexpr auto operator()(Lhs &&lhs, Rhs &&rhs) const
+ RETURN(lib::forward<Lhs>(lhs) != lib::forward<Rhs>(rhs))
+ };
+#endif
+
+#ifdef MPARK_TRANSPARENT_OPERATORS
+ using less = std::less<>;
+#else
+ struct less {
+ template <typename Lhs, typename Rhs>
+ inline constexpr auto operator()(Lhs &&lhs, Rhs &&rhs) const
+ RETURN(lib::forward<Lhs>(lhs) < lib::forward<Rhs>(rhs))
+ };
+#endif
+
+#ifdef MPARK_TRANSPARENT_OPERATORS
+ using greater = std::greater<>;
+#else
+ struct greater {
+ template <typename Lhs, typename Rhs>
+ inline constexpr auto operator()(Lhs &&lhs, Rhs &&rhs) const
+ RETURN(lib::forward<Lhs>(lhs) > lib::forward<Rhs>(rhs))
+ };
+#endif
+
+#ifdef MPARK_TRANSPARENT_OPERATORS
+ using less_equal = std::less_equal<>;
+#else
+ struct less_equal {
+ template <typename Lhs, typename Rhs>
+ inline constexpr auto operator()(Lhs &&lhs, Rhs &&rhs) const
+ RETURN(lib::forward<Lhs>(lhs) <= lib::forward<Rhs>(rhs))
+ };
+#endif
+
+#ifdef MPARK_TRANSPARENT_OPERATORS
+ using greater_equal = std::greater_equal<>;
+#else
+ struct greater_equal {
+ template <typename Lhs, typename Rhs>
+ inline constexpr auto operator()(Lhs &&lhs, Rhs &&rhs) const
+ RETURN(lib::forward<Lhs>(lhs) >= lib::forward<Rhs>(rhs))
+ };
+#endif
+ } // namespace cpp14
+
+ inline namespace cpp17 {
+
+ // <type_traits>
+ template <bool B>
+ using bool_constant = std::integral_constant<bool, B>;
+
+ template <typename...>
+ struct voider : identity<void> {};
+
+ template <typename... Ts>
+ using void_t = typename voider<Ts...>::type;
+
+ namespace detail {
+ namespace swappable {
+
+ using std::swap;
+
+ template <typename T>
+ struct is_swappable {
+ private:
+ template <typename U,
+ typename = decltype(swap(std::declval<U &>(),
+ std::declval<U &>()))>
+ inline static std::true_type test(int);
+
+ template <typename U>
+ inline static std::false_type test(...);
+
+ public:
+ static constexpr bool value = decltype(test<T>(0))::value;
+ };
+
+ template <typename T, bool = is_swappable<T>::value>
+ struct is_nothrow_swappable {
+ static constexpr bool value =
+ noexcept(swap(std::declval<T &>(), std::declval<T &>()));
+ };
+
+ template <typename T>
+ struct is_nothrow_swappable<T, false> : std::false_type {};
+
+ } // namespace swappable
+ } // namespace detail
+
+ using detail::swappable::is_swappable;
+ using detail::swappable::is_nothrow_swappable;
+
+ // <functional>
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4100)
+#endif
+ template <typename F, typename... As>
+ inline constexpr auto invoke(F &&f, As &&... as)
+ RETURN(lib::forward<F>(f)(lib::forward<As>(as)...))
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+ template <typename B, typename T, typename D>
+ inline constexpr auto invoke(T B::*pmv, D &&d)
+ RETURN(lib::forward<D>(d).*pmv)
+
+ template <typename Pmv, typename Ptr>
+ inline constexpr auto invoke(Pmv pmv, Ptr &&ptr)
+ RETURN((*lib::forward<Ptr>(ptr)).*pmv)
+
+ template <typename B, typename T, typename D, typename... As>
+ inline constexpr auto invoke(T B::*pmf, D &&d, As &&... as)
+ RETURN((lib::forward<D>(d).*pmf)(lib::forward<As>(as)...))
+
+ template <typename Pmf, typename Ptr, typename... As>
+ inline constexpr auto invoke(Pmf pmf, Ptr &&ptr, As &&... as)
+ RETURN(((*lib::forward<Ptr>(ptr)).*pmf)(lib::forward<As>(as)...))
+
+ namespace detail {
+
+ template <typename Void, typename, typename...>
+ struct invoke_result {};
+
+ template <typename F, typename... Args>
+ struct invoke_result<void_t<decltype(lib::invoke(
+ std::declval<F>(), std::declval<Args>()...))>,
+ F,
+ Args...>
+ : identity<decltype(
+ lib::invoke(std::declval<F>(), std::declval<Args>()...))> {};
+
+ } // namespace detail
+
+ template <typename F, typename... Args>
+ using invoke_result = detail::invoke_result<void, F, Args...>;
+
+ template <typename F, typename... Args>
+ using invoke_result_t = typename invoke_result<F, Args...>::type;
+
+ namespace detail {
+
+ template <typename Void, typename, typename...>
+ struct is_invocable : std::false_type {};
+
+ template <typename F, typename... Args>
+ struct is_invocable<void_t<invoke_result_t<F, Args...>>, F, Args...>
+ : std::true_type {};
+
+ template <typename Void, typename, typename, typename...>
+ struct is_invocable_r : std::false_type {};
+
+ template <typename R, typename F, typename... Args>
+ struct is_invocable_r<void_t<invoke_result_t<F, Args...>>,
+ R,
+ F,
+ Args...>
+ : std::is_convertible<invoke_result_t<F, Args...>, R> {};
+
+ } // namespace detail
+
+ template <typename F, typename... Args>
+ using is_invocable = detail::is_invocable<void, F, Args...>;
+
+ template <typename R, typename F, typename... Args>
+ using is_invocable_r = detail::is_invocable_r<void, R, F, Args...>;
+
+ // <memory>
+#ifdef MPARK_BUILTIN_ADDRESSOF
+ template <typename T>
+ inline constexpr T *addressof(T &arg) {
+ return __builtin_addressof(arg);
+ }
+#else
+ namespace detail {
+
+ namespace has_addressof_impl {
+
+ struct fail;
+
+ template <typename T>
+ inline fail operator&(T &&);
+
+ template <typename T>
+ inline static constexpr bool impl() {
+ return (std::is_class<T>::value || std::is_union<T>::value) &&
+ !std::is_same<decltype(&std::declval<T &>()), fail>::value;
+ }
+
+ } // namespace has_addressof_impl
+
+ template <typename T>
+ using has_addressof = bool_constant<has_addressof_impl::impl<T>()>;
+
+ template <typename T>
+ inline constexpr T *addressof(T &arg, std::true_type) {
+ return std::addressof(arg);
+ }
+
+ template <typename T>
+ inline constexpr T *addressof(T &arg, std::false_type) {
+ return &arg;
+ }
+
+ } // namespace detail
+
+ template <typename T>
+ inline constexpr T *addressof(T &arg) {
+ return detail::addressof(arg, detail::has_addressof<T>{});
+ }
+#endif
+
+ template <typename T>
+ inline constexpr T *addressof(const T &&) = delete;
+
+ } // namespace cpp17
+
+ template <typename T>
+ struct remove_all_extents : identity<T> {};
+
+ template <typename T, std::size_t N>
+ struct remove_all_extents<array<T, N>> : remove_all_extents<T> {};
+
+ template <typename T>
+ using remove_all_extents_t = typename remove_all_extents<T>::type;
+
+ template <std::size_t N>
+ using size_constant = std::integral_constant<std::size_t, N>;
+
+ template <std::size_t I, typename T>
+ struct indexed_type : size_constant<I>, identity<T> {};
+
+ template <bool... Bs>
+ using all = std::is_same<integer_sequence<bool, true, Bs...>,
+ integer_sequence<bool, Bs..., true>>;
+
+#ifdef MPARK_TYPE_PACK_ELEMENT
+ template <std::size_t I, typename... Ts>
+ using type_pack_element_t = __type_pack_element<I, Ts...>;
+#else
+ template <std::size_t I, typename... Ts>
+ struct type_pack_element_impl {
+ private:
+ template <typename>
+ struct set;
+
+ template <std::size_t... Is>
+ struct set<index_sequence<Is...>> : indexed_type<Is, Ts>... {};
+
+ template <typename T>
+ inline static std::enable_if<true, T> impl(indexed_type<I, T>);
+
+ inline static std::enable_if<false> impl(...);
+
+ public:
+ using type = decltype(impl(set<index_sequence_for<Ts...>>{}));
+ };
+
+ template <std::size_t I, typename... Ts>
+ using type_pack_element = typename type_pack_element_impl<I, Ts...>::type;
+
+ template <std::size_t I, typename... Ts>
+ using type_pack_element_t = typename type_pack_element<I, Ts...>::type;
+#endif
+
+#ifdef MPARK_TRIVIALITY_TYPE_TRAITS
+ using std::is_trivially_copy_constructible;
+ using std::is_trivially_move_constructible;
+ using std::is_trivially_copy_assignable;
+ using std::is_trivially_move_assignable;
+#else
+ template <typename T>
+ struct is_trivially_copy_constructible
+ : bool_constant<
+ std::is_copy_constructible<T>::value && __has_trivial_copy(T)> {};
+
+ template <typename T>
+ struct is_trivially_move_constructible : bool_constant<__is_trivial(T)> {};
+
+ template <typename T>
+ struct is_trivially_copy_assignable
+ : bool_constant<
+ std::is_copy_assignable<T>::value && __has_trivial_assign(T)> {};
+
+ template <typename T>
+ struct is_trivially_move_assignable : bool_constant<__is_trivial(T)> {};
+#endif
+
+ template <typename T, bool>
+ struct dependent_type : T {};
+
+ template <typename Is, std::size_t J>
+ struct push_back;
+
+ template <typename Is, std::size_t J>
+ using push_back_t = typename push_back<Is, J>::type;
+
+ template <std::size_t... Is, std::size_t J>
+ struct push_back<index_sequence<Is...>, J> {
+ using type = index_sequence<Is..., J>;
+ };
+
+ } // namespace lib
+} // namespace mpark
+
+#undef RETURN
+
+#endif // MPARK_LIB_HPP
+
+
+namespace mpark {
+
+#ifdef MPARK_RETURN_TYPE_DEDUCTION
+
+#define AUTO auto
+#define AUTO_RETURN(...) { return __VA_ARGS__; }
+
+#define AUTO_REFREF auto &&
+#define AUTO_REFREF_RETURN(...) { return __VA_ARGS__; }
+
+#define DECLTYPE_AUTO decltype(auto)
+#define DECLTYPE_AUTO_RETURN(...) { return __VA_ARGS__; }
+
+#else
+
+#define AUTO auto
+#define AUTO_RETURN(...) \
+ -> lib::decay_t<decltype(__VA_ARGS__)> { return __VA_ARGS__; }
+
+#define AUTO_REFREF auto
+#define AUTO_REFREF_RETURN(...) \
+ -> decltype((__VA_ARGS__)) { \
+ static_assert(std::is_reference<decltype((__VA_ARGS__))>::value, ""); \
+ return __VA_ARGS__; \
+ }
+
+#define DECLTYPE_AUTO auto
+#define DECLTYPE_AUTO_RETURN(...) \
+ -> decltype(__VA_ARGS__) { return __VA_ARGS__; }
+
+#endif
+
+ class bad_variant_access : public std::exception {
+ public:
+ virtual const char *what() const noexcept { return "bad_variant_access"; }
+ };
+
+ [[noreturn]] inline void throw_bad_variant_access() {
+#ifdef MPARK_EXCEPTIONS
+ throw bad_variant_access{};
+#else
+ std::terminate();
+#ifdef MPARK_BUILTIN_UNREACHABLE
+ __builtin_unreachable();
+#endif
+#endif
+ }
+
+ template <typename... Ts>
+ class variant;
+
+ template <typename T>
+ struct variant_size;
+
+#ifdef MPARK_VARIABLE_TEMPLATES
+ template <typename T>
+ constexpr std::size_t variant_size_v = variant_size<T>::value;
+#endif
+
+ template <typename T>
+ struct variant_size<const T> : variant_size<T> {};
+
+ template <typename T>
+ struct variant_size<volatile T> : variant_size<T> {};
+
+ template <typename T>
+ struct variant_size<const volatile T> : variant_size<T> {};
+
+ template <typename... Ts>
+ struct variant_size<variant<Ts...>> : lib::size_constant<sizeof...(Ts)> {};
+
+ template <std::size_t I, typename T>
+ struct variant_alternative;
+
+ template <std::size_t I, typename T>
+ using variant_alternative_t = typename variant_alternative<I, T>::type;
+
+ template <std::size_t I, typename T>
+ struct variant_alternative<I, const T>
+ : std::add_const<variant_alternative_t<I, T>> {};
+
+ template <std::size_t I, typename T>
+ struct variant_alternative<I, volatile T>
+ : std::add_volatile<variant_alternative_t<I, T>> {};
+
+ template <std::size_t I, typename T>
+ struct variant_alternative<I, const volatile T>
+ : std::add_cv<variant_alternative_t<I, T>> {};
+
+ template <std::size_t I, typename... Ts>
+ struct variant_alternative<I, variant<Ts...>> {
+ static_assert(I < sizeof...(Ts),
+ "Index out of bounds in std::variant_alternative<>");
+ using type = lib::type_pack_element_t<I, Ts...>;
+ };
+
+ constexpr std::size_t variant_npos = static_cast<std::size_t>(-1);
+
+ namespace detail {
+
+ constexpr std::size_t not_found = static_cast<std::size_t>(-1);
+ constexpr std::size_t ambiguous = static_cast<std::size_t>(-2);
+
+#ifdef MPARK_CPP14_CONSTEXPR
+ template <typename T, typename... Ts>
+ inline constexpr std::size_t find_index() {
+ constexpr lib::array<bool, sizeof...(Ts)> matches = {
+ {std::is_same<T, Ts>::value...}
+ };
+ std::size_t result = not_found;
+ for (std::size_t i = 0; i < sizeof...(Ts); ++i) {
+ if (matches[i]) {
+ if (result != not_found) {
+ return ambiguous;
+ }
+ result = i;
+ }
+ }
+ return result;
+ }
+#else
+ inline constexpr std::size_t find_index_impl(std::size_t result,
+ std::size_t) {
+ return result;
+ }
+
+ template <typename... Bs>
+ inline constexpr std::size_t find_index_impl(std::size_t result,
+ std::size_t idx,
+ bool b,
+ Bs... bs) {
+ return b ? (result != not_found ? ambiguous
+ : find_index_impl(idx, idx + 1, bs...))
+ : find_index_impl(result, idx + 1, bs...);
+ }
+
+ template <typename T, typename... Ts>
+ inline constexpr std::size_t find_index() {
+ return find_index_impl(not_found, 0, std::is_same<T, Ts>::value...);
+ }
+#endif
+
+ template <std::size_t I>
+ using find_index_sfinae_impl =
+ lib::enable_if_t<I != not_found && I != ambiguous,
+ lib::size_constant<I>>;
+
+ template <typename T, typename... Ts>
+ using find_index_sfinae = find_index_sfinae_impl<find_index<T, Ts...>()>;
+
+ template <std::size_t I>
+ struct find_index_checked_impl : lib::size_constant<I> {
+ static_assert(I != not_found, "the specified type is not found.");
+ static_assert(I != ambiguous, "the specified type is ambiguous.");
+ };
+
+ template <typename T, typename... Ts>
+ using find_index_checked = find_index_checked_impl<find_index<T, Ts...>()>;
+
+ struct valueless_t {};
+
+ enum class Trait { TriviallyAvailable, Available, Unavailable };
+
+ template <typename T,
+ template <typename> class IsTriviallyAvailable,
+ template <typename> class IsAvailable>
+ inline constexpr Trait trait() {
+ return IsTriviallyAvailable<T>::value
+ ? Trait::TriviallyAvailable
+ : IsAvailable<T>::value ? Trait::Available
+ : Trait::Unavailable;
+ }
+
+#ifdef MPARK_CPP14_CONSTEXPR
+ template <typename... Traits>
+ inline constexpr Trait common_trait(Traits... traits) {
+ Trait result = Trait::TriviallyAvailable;
+ for (Trait t : {traits...}) {
+ if (static_cast<int>(t) > static_cast<int>(result)) {
+ result = t;
+ }
+ }
+ return result;
+ }
+#else
+ inline constexpr Trait common_trait_impl(Trait result) { return result; }
+
+ template <typename... Traits>
+ inline constexpr Trait common_trait_impl(Trait result,
+ Trait t,
+ Traits... ts) {
+ return static_cast<int>(t) > static_cast<int>(result)
+ ? common_trait_impl(t, ts...)
+ : common_trait_impl(result, ts...);
+ }
+
+ template <typename... Traits>
+ inline constexpr Trait common_trait(Traits... ts) {
+ return common_trait_impl(Trait::TriviallyAvailable, ts...);
+ }
+#endif
+
+ template <typename... Ts>
+ struct traits {
+ static constexpr Trait copy_constructible_trait =
+ common_trait(trait<Ts,
+ lib::is_trivially_copy_constructible,
+ std::is_copy_constructible>()...);
+
+ static constexpr Trait move_constructible_trait =
+ common_trait(trait<Ts,
+ lib::is_trivially_move_constructible,
+ std::is_move_constructible>()...);
+
+ static constexpr Trait copy_assignable_trait =
+ common_trait(copy_constructible_trait,
+ trait<Ts,
+ lib::is_trivially_copy_assignable,
+ std::is_copy_assignable>()...);
+
+ static constexpr Trait move_assignable_trait =
+ common_trait(move_constructible_trait,
+ trait<Ts,
+ lib::is_trivially_move_assignable,
+ std::is_move_assignable>()...);
+
+ static constexpr Trait destructible_trait =
+ common_trait(trait<Ts,
+ std::is_trivially_destructible,
+ std::is_destructible>()...);
+ };
+
+ namespace access {
+
+ struct recursive_union {
+#ifdef MPARK_RETURN_TYPE_DEDUCTION
+ template <typename V>
+ inline static constexpr auto &&get_alt(V &&v, in_place_index_t<0>) {
+ return lib::forward<V>(v).head_;
+ }
+
+ template <typename V, std::size_t I>
+ inline static constexpr auto &&get_alt(V &&v, in_place_index_t<I>) {
+ return get_alt(lib::forward<V>(v).tail_, in_place_index_t<I - 1>{});
+ }
+#else
+ template <std::size_t I, bool Dummy = true>
+ struct get_alt_impl {
+ template <typename V>
+ inline constexpr AUTO_REFREF operator()(V &&v) const
+ AUTO_REFREF_RETURN(get_alt_impl<I - 1>{}(lib::forward<V>(v).tail_))
+ };
+
+ template <bool Dummy>
+ struct get_alt_impl<0, Dummy> {
+ template <typename V>
+ inline constexpr AUTO_REFREF operator()(V &&v) const
+ AUTO_REFREF_RETURN(lib::forward<V>(v).head_)
+ };
+
+ template <typename V, std::size_t I>
+ inline static constexpr AUTO_REFREF get_alt(V &&v, in_place_index_t<I>)
+ AUTO_REFREF_RETURN(get_alt_impl<I>{}(lib::forward<V>(v)))
+#endif
+ };
+
+ struct base {
+ template <std::size_t I, typename V>
+ inline static constexpr AUTO_REFREF get_alt(V &&v)
+ AUTO_REFREF_RETURN(recursive_union::get_alt(
+ data(lib::forward<V>(v)), in_place_index_t<I>{}))
+ };
+
+ struct variant {
+ template <std::size_t I, typename V>
+ inline static constexpr AUTO_REFREF get_alt(V &&v)
+ AUTO_REFREF_RETURN(base::get_alt<I>(lib::forward<V>(v).impl_))
+ };
+
+ } // namespace access
+
+ namespace visitation {
+
+ struct base {
+ template <typename T>
+ inline static constexpr const T &at(const T &elem) {
+ return elem;
+ }
+
+ template <typename T, std::size_t N, typename... Is>
+ inline static constexpr const lib::remove_all_extents_t<T> &at(
+ const lib::array<T, N> &elems, std::size_t i, Is... is) {
+ return at(elems[i], is...);
+ }
+
+ template <typename F, typename... Fs>
+ inline static constexpr int visit_visitor_return_type_check() {
+ static_assert(lib::all<std::is_same<F, Fs>::value...>::value,
+ "`mpark::visit` requires the visitor to have a single "
+ "return type.");
+ return 0;
+ }
+
+ template <typename... Fs>
+ inline static constexpr lib::array<
+ lib::common_type_t<lib::decay_t<Fs>...>,
+ sizeof...(Fs)>
+ make_farray(Fs &&... fs) {
+ using result = lib::array<lib::common_type_t<lib::decay_t<Fs>...>,
+ sizeof...(Fs)>;
+ return visit_visitor_return_type_check<lib::decay_t<Fs>...>(),
+ result{{lib::forward<Fs>(fs)...}};
+ }
+
+ template <std::size_t... Is>
+ struct dispatcher {
+ template <typename F, typename... Vs>
+ struct impl {
+ inline static constexpr DECLTYPE_AUTO dispatch(F f, Vs... vs)
+ DECLTYPE_AUTO_RETURN(lib::invoke(
+ static_cast<F>(f),
+ access::base::get_alt<Is>(static_cast<Vs>(vs))...))
+ };
+ };
+
+ template <typename F, typename... Vs, std::size_t... Is>
+ inline static constexpr AUTO make_dispatch(lib::index_sequence<Is...>)
+ AUTO_RETURN(&dispatcher<Is...>::template impl<F, Vs...>::dispatch)
+
+ template <std::size_t I, typename F, typename... Vs>
+ inline static constexpr AUTO make_fdiagonal_impl()
+ AUTO_RETURN(make_dispatch<F, Vs...>(
+ lib::index_sequence<lib::indexed_type<I, Vs>::value...>{}))
+
+ template <typename F, typename... Vs, std::size_t... Is>
+ inline static constexpr AUTO make_fdiagonal_impl(
+ lib::index_sequence<Is...>)
+ AUTO_RETURN(make_farray(make_fdiagonal_impl<Is, F, Vs...>()...))
+
+ template <typename F, typename V, typename... Vs>
+ inline static constexpr /* auto * */ auto make_fdiagonal()
+ -> decltype(make_fdiagonal_impl<F, V, Vs...>(
+ lib::make_index_sequence<lib::decay_t<V>::size()>{})) {
+ static_assert(lib::all<(lib::decay_t<V>::size() ==
+ lib::decay_t<Vs>::size())...>::value,
+ "all of the variants must be the same size.");
+ return make_fdiagonal_impl<F, V, Vs...>(
+ lib::make_index_sequence<lib::decay_t<V>::size()>{});
+ }
+
+#ifdef MPARK_RETURN_TYPE_DEDUCTION
+ template <typename F, typename... Vs, typename Is>
+ inline static constexpr auto make_fmatrix_impl(Is is) {
+ return make_dispatch<F, Vs...>(is);
+ }
+
+ template <typename F,
+ typename... Vs,
+ typename Is,
+ std::size_t... Js,
+ typename... Ls>
+ inline static constexpr auto make_fmatrix_impl(
+ Is, lib::index_sequence<Js...>, Ls... ls) {
+ return make_farray(make_fmatrix_impl<F, Vs...>(
+ lib::push_back_t<Is, Js>{}, ls...)...);
+ }
+
+ template <typename F, typename... Vs>
+ inline static constexpr auto make_fmatrix() {
+ return make_fmatrix_impl<F, Vs...>(
+ lib::index_sequence<>{},
+ lib::make_index_sequence<lib::decay_t<Vs>::size()>{}...);
+ }
+#else
+ template <typename F, typename... Vs>
+ struct make_fmatrix_impl {
+ template <typename...>
+ struct impl;
+
+ template <typename Is>
+ struct impl<Is> {
+ inline constexpr AUTO operator()() const
+ AUTO_RETURN(make_dispatch<F, Vs...>(Is{}))
+ };
+
+ template <typename Is, std::size_t... Js, typename... Ls>
+ struct impl<Is, lib::index_sequence<Js...>, Ls...> {
+ inline constexpr AUTO operator()() const
+ AUTO_RETURN(
+ make_farray(impl<lib::push_back_t<Is, Js>, Ls...>{}()...))
+ };
+ };
+
+ template <typename F, typename... Vs>
+ inline static constexpr AUTO make_fmatrix()
+ AUTO_RETURN(
+ typename make_fmatrix_impl<F, Vs...>::template impl<
+ lib::index_sequence<>,
+ lib::make_index_sequence<lib::decay_t<Vs>::size()>...>{}())
+#endif
+ }; // namespace base
+
+ template <typename F, typename... Vs>
+ using FDiagonal = decltype(base::make_fdiagonal<F, Vs...>());
+
+ template <typename F, typename... Vs>
+ struct fdiagonal {
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4268)
+#endif
+ static constexpr FDiagonal<F, Vs...> value =
+ base::make_fdiagonal<F, Vs...>();
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+ };
+
+ template <typename F, typename... Vs>
+ constexpr FDiagonal<F, Vs...> fdiagonal<F, Vs...>::value;
+
+ template <typename F, typename... Vs>
+ using FMatrix = decltype(base::make_fmatrix<F, Vs...>());
+
+ template <typename F, typename... Vs>
+ struct fmatrix {
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4268)
+#endif
+ static constexpr FMatrix<F, Vs...> value =
+ base::make_fmatrix<F, Vs...>();
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+ };
+
+ template <typename F, typename... Vs>
+ constexpr FMatrix<F, Vs...> fmatrix<F, Vs...>::value;
+
+ struct alt {
+ template <typename Visitor, typename... Vs>
+ inline static constexpr DECLTYPE_AUTO visit_alt_at(std::size_t index,
+ Visitor &&visitor,
+ Vs &&... vs)
+ DECLTYPE_AUTO_RETURN(base::at(
+ fdiagonal<Visitor &&,
+ decltype(as_base(lib::forward<Vs>(vs)))...>::value,
+ index)(lib::forward<Visitor>(visitor),
+ as_base(lib::forward<Vs>(vs))...))
+
+ template <typename Visitor, typename... Vs>
+ inline static constexpr DECLTYPE_AUTO visit_alt(Visitor &&visitor,
+ Vs &&... vs)
+ DECLTYPE_AUTO_RETURN(base::at(
+ fmatrix<Visitor &&,
+ decltype(as_base(lib::forward<Vs>(vs)))...>::value,
+ vs.index()...)(lib::forward<Visitor>(visitor),
+ as_base(lib::forward<Vs>(vs))...))
+ };
+
+ struct variant {
+ private:
+ template <typename Visitor, typename... Values>
+ struct visit_exhaustive_visitor_check {
+ static_assert(
+ lib::is_invocable<Visitor, Values...>::value,
+ "`mpark::visit` requires the visitor to be exhaustive.");
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4100)
+#endif
+ inline constexpr DECLTYPE_AUTO operator()(Visitor &&visitor,
+ Values &&... values) const
+ DECLTYPE_AUTO_RETURN(lib::invoke(lib::forward<Visitor>(visitor),
+ lib::forward<Values>(values)...))
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+ };
+
+ template <typename Visitor>
+ struct value_visitor {
+ Visitor &&visitor_;
+
+ template <typename... Alts>
+ inline constexpr DECLTYPE_AUTO operator()(Alts &&... alts) const
+ DECLTYPE_AUTO_RETURN(
+ visit_exhaustive_visitor_check<
+ Visitor,
+ decltype((lib::forward<Alts>(alts).value))...>{}(
+ lib::forward<Visitor>(visitor_),
+ lib::forward<Alts>(alts).value...))
+ };
+
+ template <typename Visitor>
+ inline static constexpr AUTO make_value_visitor(Visitor &&visitor)
+ AUTO_RETURN(value_visitor<Visitor>{lib::forward<Visitor>(visitor)})
+
+ public:
+ template <typename Visitor, typename... Vs>
+ inline static constexpr DECLTYPE_AUTO visit_alt_at(std::size_t index,
+ Visitor &&visitor,
+ Vs &&... vs)
+ DECLTYPE_AUTO_RETURN(
+ alt::visit_alt_at(index,
+ lib::forward<Visitor>(visitor),
+ lib::forward<Vs>(vs).impl_...))
+
+ template <typename Visitor, typename... Vs>
+ inline static constexpr DECLTYPE_AUTO visit_alt(Visitor &&visitor,
+ Vs &&... vs)
+ DECLTYPE_AUTO_RETURN(alt::visit_alt(lib::forward<Visitor>(visitor),
+ lib::forward<Vs>(vs).impl_...))
+
+ template <typename Visitor, typename... Vs>
+ inline static constexpr DECLTYPE_AUTO visit_value_at(std::size_t index,
+ Visitor &&visitor,
+ Vs &&... vs)
+ DECLTYPE_AUTO_RETURN(
+ visit_alt_at(index,
+ make_value_visitor(lib::forward<Visitor>(visitor)),
+ lib::forward<Vs>(vs)...))
+
+ template <typename Visitor, typename... Vs>
+ inline static constexpr DECLTYPE_AUTO visit_value(Visitor &&visitor,
+ Vs &&... vs)
+ DECLTYPE_AUTO_RETURN(
+ visit_alt(make_value_visitor(lib::forward<Visitor>(visitor)),
+ lib::forward<Vs>(vs)...))
+ };
+
+ } // namespace visitation
+
+ template <std::size_t Index, typename T>
+ struct alt {
+ using value_type = T;
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4244)
+#endif
+ template <typename... Args>
+ inline explicit constexpr alt(in_place_t, Args &&... args)
+ : value(lib::forward<Args>(args)...) {}
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+ T value;
+ };
+
+ template <Trait DestructibleTrait, std::size_t Index, typename... Ts>
+ union recursive_union;
+
+ template <Trait DestructibleTrait, std::size_t Index>
+ union recursive_union<DestructibleTrait, Index> {};
+
+#define MPARK_VARIANT_RECURSIVE_UNION(destructible_trait, destructor) \
+ template <std::size_t Index, typename T, typename... Ts> \
+ union recursive_union<destructible_trait, Index, T, Ts...> { \
+ public: \
+ inline explicit constexpr recursive_union(valueless_t) noexcept \
+ : dummy_{} {} \
+ \
+ template <typename... Args> \
+ inline explicit constexpr recursive_union(in_place_index_t<0>, \
+ Args &&... args) \
+ : head_(in_place_t{}, lib::forward<Args>(args)...) {} \
+ \
+ template <std::size_t I, typename... Args> \
+ inline explicit constexpr recursive_union(in_place_index_t<I>, \
+ Args &&... args) \
+ : tail_(in_place_index_t<I - 1>{}, lib::forward<Args>(args)...) {} \
+ \
+ recursive_union(const recursive_union &) = default; \
+ recursive_union(recursive_union &&) = default; \
+ \
+ destructor \
+ \
+ recursive_union &operator=(const recursive_union &) = default; \
+ recursive_union &operator=(recursive_union &&) = default; \
+ \
+ private: \
+ char dummy_; \
+ alt<Index, T> head_; \
+ recursive_union<destructible_trait, Index + 1, Ts...> tail_; \
+ \
+ friend struct access::recursive_union; \
+ }
+
+ MPARK_VARIANT_RECURSIVE_UNION(Trait::TriviallyAvailable,
+ ~recursive_union() = default;);
+ MPARK_VARIANT_RECURSIVE_UNION(Trait::Available,
+ ~recursive_union() {});
+ MPARK_VARIANT_RECURSIVE_UNION(Trait::Unavailable,
+ ~recursive_union() = delete;);
+
+#undef MPARK_VARIANT_RECURSIVE_UNION
+
+ using index_t = unsigned int;
+
+ template <Trait DestructibleTrait, typename... Ts>
+ class base {
+ public:
+ inline explicit constexpr base(valueless_t tag) noexcept
+ : data_(tag), index_(static_cast<index_t>(-1)) {}
+
+ template <std::size_t I, typename... Args>
+ inline explicit constexpr base(in_place_index_t<I>, Args &&... args)
+ : data_(in_place_index_t<I>{}, lib::forward<Args>(args)...),
+ index_(I) {}
+
+ inline constexpr bool valueless_by_exception() const noexcept {
+ return index_ == static_cast<index_t>(-1);
+ }
+
+ inline constexpr std::size_t index() const noexcept {
+ return valueless_by_exception() ? variant_npos : index_;
+ }
+
+ protected:
+ using data_t = recursive_union<DestructibleTrait, 0, Ts...>;
+
+ friend inline constexpr base &as_base(base &b) { return b; }
+ friend inline constexpr const base &as_base(const base &b) { return b; }
+ friend inline constexpr base &&as_base(base &&b) { return lib::move(b); }
+ friend inline constexpr const base &&as_base(const base &&b) { return lib::move(b); }
+
+ friend inline constexpr data_t &data(base &b) { return b.data_; }
+ friend inline constexpr const data_t &data(const base &b) { return b.data_; }
+ friend inline constexpr data_t &&data(base &&b) { return lib::move(b).data_; }
+ friend inline constexpr const data_t &&data(const base &&b) { return lib::move(b).data_; }
+
+ inline static constexpr std::size_t size() { return sizeof...(Ts); }
+
+ data_t data_;
+ index_t index_;
+
+ friend struct access::base;
+ friend struct visitation::base;
+ };
+
+ struct dtor {
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4100)
+#endif
+ template <typename Alt>
+ inline void operator()(Alt &alt) const noexcept { alt.~Alt(); }
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+ };
+
+#if defined(_MSC_VER) && _MSC_VER < 1910
+#define INHERITING_CTOR(type, base) \
+ template <typename... Args> \
+ inline explicit constexpr type(Args &&... args) \
+ : base(lib::forward<Args>(args)...) {}
+#else
+#define INHERITING_CTOR(type, base) using base::base;
+#endif
+
+ template <typename Traits, Trait = Traits::destructible_trait>
+ class destructor;
+
+#define MPARK_VARIANT_DESTRUCTOR(destructible_trait, definition, destroy) \
+ template <typename... Ts> \
+ class destructor<traits<Ts...>, destructible_trait> \
+ : public base<destructible_trait, Ts...> { \
+ using super = base<destructible_trait, Ts...>; \
+ \
+ public: \
+ INHERITING_CTOR(destructor, super) \
+ using super::operator=; \
+ \
+ destructor(const destructor &) = default; \
+ destructor(destructor &&) = default; \
+ definition \
+ destructor &operator=(const destructor &) = default; \
+ destructor &operator=(destructor &&) = default; \
+ \
+ protected: \
+ destroy \
+ }
+
+ MPARK_VARIANT_DESTRUCTOR(
+ Trait::TriviallyAvailable,
+ ~destructor() = default;,
+ inline void destroy() noexcept {
+ this->index_ = static_cast<index_t>(-1);
+ });
+
+ MPARK_VARIANT_DESTRUCTOR(
+ Trait::Available,
+ ~destructor() { destroy(); },
+ inline void destroy() noexcept {
+ if (!this->valueless_by_exception()) {
+ visitation::alt::visit_alt(dtor{}, *this);
+ }
+ this->index_ = static_cast<index_t>(-1);
+ });
+
+ MPARK_VARIANT_DESTRUCTOR(
+ Trait::Unavailable,
+ ~destructor() = delete;,
+ inline void destroy() noexcept = delete;);
+
+#undef MPARK_VARIANT_DESTRUCTOR
+
+ template <typename Traits>
+ class constructor : public destructor<Traits> {
+ using super = destructor<Traits>;
+
+ public:
+ INHERITING_CTOR(constructor, super)
+ using super::operator=;
+
+ protected:
+#ifndef MPARK_GENERIC_LAMBDAS
+ struct ctor {
+ template <typename LhsAlt, typename RhsAlt>
+ inline void operator()(LhsAlt &lhs_alt, RhsAlt &&rhs_alt) const {
+ constructor::construct_alt(lhs_alt,
+ lib::forward<RhsAlt>(rhs_alt).value);
+ }
+ };
+#endif
+
+ template <std::size_t I, typename T, typename... Args>
+ inline static T &construct_alt(alt<I, T> &a, Args &&... args) {
+ ::new (static_cast<void *>(lib::addressof(a)))
+ alt<I, T>(in_place_t{}, lib::forward<Args>(args)...);
+ return a.value;
+ }
+
+ template <typename Rhs>
+ inline static void generic_construct(constructor &lhs, Rhs &&rhs) {
+ lhs.destroy();
+ if (!rhs.valueless_by_exception()) {
+ visitation::alt::visit_alt_at(
+ rhs.index(),
+#ifdef MPARK_GENERIC_LAMBDAS
+ [](auto &lhs_alt, auto &&rhs_alt) {
+ constructor::construct_alt(
+ lhs_alt, lib::forward<decltype(rhs_alt)>(rhs_alt).value);
+ }
+#else
+ ctor{}
+#endif
+ ,
+ lhs,
+ lib::forward<Rhs>(rhs));
+ lhs.index_ = rhs.index_;
+ }
+ }
+ };
+
+ template <typename Traits, Trait = Traits::move_constructible_trait>
+ class move_constructor;
+
+#define MPARK_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, definition) \
+ template <typename... Ts> \
+ class move_constructor<traits<Ts...>, move_constructible_trait> \
+ : public constructor<traits<Ts...>> { \
+ using super = constructor<traits<Ts...>>; \
+ \
+ public: \
+ INHERITING_CTOR(move_constructor, super) \
+ using super::operator=; \
+ \
+ move_constructor(const move_constructor &) = default; \
+ definition \
+ ~move_constructor() = default; \
+ move_constructor &operator=(const move_constructor &) = default; \
+ move_constructor &operator=(move_constructor &&) = default; \
+ }
+
+ MPARK_VARIANT_MOVE_CONSTRUCTOR(
+ Trait::TriviallyAvailable,
+ move_constructor(move_constructor &&that) = default;);
+
+ MPARK_VARIANT_MOVE_CONSTRUCTOR(
+ Trait::Available,
+ move_constructor(move_constructor &&that) noexcept(
+ lib::all<std::is_nothrow_move_constructible<Ts>::value...>::value)
+ : move_constructor(valueless_t{}) {
+ this->generic_construct(*this, lib::move(that));
+ });
+
+ MPARK_VARIANT_MOVE_CONSTRUCTOR(
+ Trait::Unavailable,
+ move_constructor(move_constructor &&) = delete;);
+
+#undef MPARK_VARIANT_MOVE_CONSTRUCTOR
+
+ template <typename Traits, Trait = Traits::copy_constructible_trait>
+ class copy_constructor;
+
+#define MPARK_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, definition) \
+ template <typename... Ts> \
+ class copy_constructor<traits<Ts...>, copy_constructible_trait> \
+ : public move_constructor<traits<Ts...>> { \
+ using super = move_constructor<traits<Ts...>>; \
+ \
+ public: \
+ INHERITING_CTOR(copy_constructor, super) \
+ using super::operator=; \
+ \
+ definition \
+ copy_constructor(copy_constructor &&) = default; \
+ ~copy_constructor() = default; \
+ copy_constructor &operator=(const copy_constructor &) = default; \
+ copy_constructor &operator=(copy_constructor &&) = default; \
+ }
+
+ MPARK_VARIANT_COPY_CONSTRUCTOR(
+ Trait::TriviallyAvailable,
+ copy_constructor(const copy_constructor &that) = default;);
+
+ MPARK_VARIANT_COPY_CONSTRUCTOR(
+ Trait::Available,
+ copy_constructor(const copy_constructor &that)
+ : copy_constructor(valueless_t{}) {
+ this->generic_construct(*this, that);
+ });
+
+ MPARK_VARIANT_COPY_CONSTRUCTOR(
+ Trait::Unavailable,
+ copy_constructor(const copy_constructor &) = delete;);
+
+#undef MPARK_VARIANT_COPY_CONSTRUCTOR
+
+ template <typename Traits>
+ class assignment : public copy_constructor<Traits> {
+ using super = copy_constructor<Traits>;
+
+ public:
+ INHERITING_CTOR(assignment, super)
+ using super::operator=;
+
+ template <std::size_t I, typename... Args>
+ inline /* auto & */ auto emplace(Args &&... args)
+ -> decltype(this->construct_alt(access::base::get_alt<I>(*this),
+ lib::forward<Args>(args)...)) {
+ this->destroy();
+ auto &result = this->construct_alt(access::base::get_alt<I>(*this),
+ lib::forward<Args>(args)...);
+ this->index_ = I;
+ return result;
+ }
+
+ protected:
+#ifndef MPARK_GENERIC_LAMBDAS
+ template <typename That>
+ struct assigner {
+ template <typename ThisAlt, typename ThatAlt>
+ inline void operator()(ThisAlt &this_alt, ThatAlt &&that_alt) const {
+ self->assign_alt(this_alt, lib::forward<ThatAlt>(that_alt).value);
+ }
+ assignment *self;
+ };
+#endif
+
+ template <std::size_t I, typename T, typename Arg>
+ inline void assign_alt(alt<I, T> &a, Arg &&arg) {
+ if (this->index() == I) {
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4244)
+#endif
+ a.value = lib::forward<Arg>(arg);
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+ } else {
+ struct {
+ void operator()(std::true_type) const {
+ this_->emplace<I>(lib::forward<Arg>(arg_));
+ }
+ void operator()(std::false_type) const {
+ this_->emplace<I>(T(lib::forward<Arg>(arg_)));
+ }
+ assignment *this_;
+ Arg &&arg_;
+ } impl{this, lib::forward<Arg>(arg)};
+ impl(lib::bool_constant<
+ std::is_nothrow_constructible<T, Arg>::value ||
+ !std::is_nothrow_move_constructible<T>::value>{});
+ }
+ }
+
+ template <typename That>
+ inline void generic_assign(That &&that) {
+ if (this->valueless_by_exception() && that.valueless_by_exception()) {
+ // do nothing.
+ } else if (that.valueless_by_exception()) {
+ this->destroy();
+ } else {
+ visitation::alt::visit_alt_at(
+ that.index(),
+#ifdef MPARK_GENERIC_LAMBDAS
+ [this](auto &this_alt, auto &&that_alt) {
+ this->assign_alt(
+ this_alt, lib::forward<decltype(that_alt)>(that_alt).value);
+ }
+#else
+ assigner<That>{this}
+#endif
+ ,
+ *this,
+ lib::forward<That>(that));
+ }
+ }
+ };
+
+ template <typename Traits, Trait = Traits::move_assignable_trait>
+ class move_assignment;
+
+#define MPARK_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, definition) \
+ template <typename... Ts> \
+ class move_assignment<traits<Ts...>, move_assignable_trait> \
+ : public assignment<traits<Ts...>> { \
+ using super = assignment<traits<Ts...>>; \
+ \
+ public: \
+ INHERITING_CTOR(move_assignment, super) \
+ using super::operator=; \
+ \
+ move_assignment(const move_assignment &) = default; \
+ move_assignment(move_assignment &&) = default; \
+ ~move_assignment() = default; \
+ move_assignment &operator=(const move_assignment &) = default; \
+ definition \
+ }
+
+ MPARK_VARIANT_MOVE_ASSIGNMENT(
+ Trait::TriviallyAvailable,
+ move_assignment &operator=(move_assignment &&that) = default;);
+
+ MPARK_VARIANT_MOVE_ASSIGNMENT(
+ Trait::Available,
+ move_assignment &
+ operator=(move_assignment &&that) noexcept(
+ lib::all<(std::is_nothrow_move_constructible<Ts>::value &&
+ std::is_nothrow_move_assignable<Ts>::value)...>::value) {
+ this->generic_assign(lib::move(that));
+ return *this;
+ });
+
+ MPARK_VARIANT_MOVE_ASSIGNMENT(
+ Trait::Unavailable,
+ move_assignment &operator=(move_assignment &&) = delete;);
+
+#undef MPARK_VARIANT_MOVE_ASSIGNMENT
+
+ template <typename Traits, Trait = Traits::copy_assignable_trait>
+ class copy_assignment;
+
+#define MPARK_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait, definition) \
+ template <typename... Ts> \
+ class copy_assignment<traits<Ts...>, copy_assignable_trait> \
+ : public move_assignment<traits<Ts...>> { \
+ using super = move_assignment<traits<Ts...>>; \
+ \
+ public: \
+ INHERITING_CTOR(copy_assignment, super) \
+ using super::operator=; \
+ \
+ copy_assignment(const copy_assignment &) = default; \
+ copy_assignment(copy_assignment &&) = default; \
+ ~copy_assignment() = default; \
+ definition \
+ copy_assignment &operator=(copy_assignment &&) = default; \
+ }
+
+ MPARK_VARIANT_COPY_ASSIGNMENT(
+ Trait::TriviallyAvailable,
+ copy_assignment &operator=(const copy_assignment &that) = default;);
+
+ MPARK_VARIANT_COPY_ASSIGNMENT(
+ Trait::Available,
+ copy_assignment &operator=(const copy_assignment &that) {
+ this->generic_assign(that);
+ return *this;
+ });
+
+ MPARK_VARIANT_COPY_ASSIGNMENT(
+ Trait::Unavailable,
+ copy_assignment &operator=(const copy_assignment &) = delete;);
+
+#undef MPARK_VARIANT_COPY_ASSIGNMENT
+
+ template <typename... Ts>
+ class impl : public copy_assignment<traits<Ts...>> {
+ using super = copy_assignment<traits<Ts...>>;
+
+ public:
+ INHERITING_CTOR(impl, super)
+ using super::operator=;
+
+ template <std::size_t I, typename Arg>
+ inline void assign(Arg &&arg) {
+ this->assign_alt(access::base::get_alt<I>(*this),
+ lib::forward<Arg>(arg));
+ }
+
+ inline void swap(impl &that) {
+ if (this->valueless_by_exception() && that.valueless_by_exception()) {
+ // do nothing.
+ } else if (this->index() == that.index()) {
+ visitation::alt::visit_alt_at(this->index(),
+#ifdef MPARK_GENERIC_LAMBDAS
+ [](auto &this_alt, auto &that_alt) {
+ using std::swap;
+ swap(this_alt.value,
+ that_alt.value);
+ }
+#else
+ swapper{}
+#endif
+ ,
+ *this,
+ that);
+ } else {
+ impl *lhs = this;
+ impl *rhs = lib::addressof(that);
+ if (lhs->move_nothrow() && !rhs->move_nothrow()) {
+ std::swap(lhs, rhs);
+ }
+ impl tmp(lib::move(*rhs));
+#ifdef MPARK_EXCEPTIONS
+ // EXTENSION: When the move construction of `lhs` into `rhs` throws
+ // and `tmp` is nothrow move constructible then we move `tmp` back
+ // into `rhs` and provide the strong exception safety guarantee.
+ try {
+ this->generic_construct(*rhs, lib::move(*lhs));
+ } catch (...) {
+ if (tmp.move_nothrow()) {
+ this->generic_construct(*rhs, lib::move(tmp));
+ }
+ throw;
+ }
+#else
+ this->generic_construct(*rhs, lib::move(*lhs));
+#endif
+ this->generic_construct(*lhs, lib::move(tmp));
+ }
+ }
+
+ private:
+#ifndef MPARK_GENERIC_LAMBDAS
+ struct swapper {
+ template <typename ThisAlt, typename ThatAlt>
+ inline void operator()(ThisAlt &this_alt, ThatAlt &that_alt) const {
+ using std::swap;
+ swap(this_alt.value, that_alt.value);
+ }
+ };
+#endif
+
+ inline constexpr bool move_nothrow() const {
+ return this->valueless_by_exception() ||
+ lib::array<bool, sizeof...(Ts)>{
+ {std::is_nothrow_move_constructible<Ts>::value...}
+ }[this->index()];
+ }
+ };
+
+ template <std::size_t I, typename T>
+ struct overload_leaf {
+ using F = lib::size_constant<I> (*)(T);
+ operator F() const { return nullptr; }
+ };
+
+ template <typename... Ts>
+ struct overload_impl {
+ private:
+ template <typename>
+ struct impl;
+
+ template <std::size_t... Is>
+ struct impl<lib::index_sequence<Is...>> : overload_leaf<Is, Ts>... {};
+
+ public:
+ using type = impl<lib::index_sequence_for<Ts...>>;
+ };
+
+ template <typename... Ts>
+ using overload = typename overload_impl<Ts...>::type;
+
+ template <typename T, typename... Ts>
+ using best_match = lib::invoke_result_t<overload<Ts...>, T &&>;
+
+ template <typename T>
+ struct is_in_place_index : std::false_type {};
+
+ template <std::size_t I>
+ struct is_in_place_index<in_place_index_t<I>> : std::true_type {};
+
+ template <typename T>
+ struct is_in_place_type : std::false_type {};
+
+ template <typename T>
+ struct is_in_place_type<in_place_type_t<T>> : std::true_type {};
+
+ } // detail
+
+ template <typename... Ts>
+ class variant {
+ static_assert(0 < sizeof...(Ts),
+ "variant must consist of at least one alternative.");
+
+ static_assert(lib::all<!std::is_array<Ts>::value...>::value,
+ "variant can not have an array type as an alternative.");
+
+ static_assert(lib::all<!std::is_reference<Ts>::value...>::value,
+ "variant can not have a reference type as an alternative.");
+
+ static_assert(lib::all<!std::is_void<Ts>::value...>::value,
+ "variant can not have a void type as an alternative.");
+
+ public:
+ template <
+ typename Front = lib::type_pack_element_t<0, Ts...>,
+ lib::enable_if_t<std::is_default_constructible<Front>::value, int> = 0>
+ inline constexpr variant() noexcept(
+ std::is_nothrow_default_constructible<Front>::value)
+ : impl_(in_place_index_t<0>{}) {}
+
+ variant(const variant &) = default;
+ variant(variant &&) = default;
+
+ template <
+ typename Arg,
+ typename Decayed = lib::decay_t<Arg>,
+ lib::enable_if_t<!std::is_same<Decayed, variant>::value, int> = 0,
+ lib::enable_if_t<!detail::is_in_place_index<Decayed>::value, int> = 0,
+ lib::enable_if_t<!detail::is_in_place_type<Decayed>::value, int> = 0,
+ std::size_t I = detail::best_match<Arg, Ts...>::value,
+ typename T = lib::type_pack_element_t<I, Ts...>,
+ lib::enable_if_t<std::is_constructible<T, Arg>::value, int> = 0>
+ inline constexpr variant(Arg &&arg) noexcept(
+ std::is_nothrow_constructible<T, Arg>::value)
+ : impl_(in_place_index_t<I>{}, lib::forward<Arg>(arg)) {}
+
+ template <
+ std::size_t I,
+ typename... Args,
+ typename T = lib::type_pack_element_t<I, Ts...>,
+ lib::enable_if_t<std::is_constructible<T, Args...>::value, int> = 0>
+ inline explicit constexpr variant(
+ in_place_index_t<I>,
+ Args &&... args) noexcept(std::is_nothrow_constructible<T,
+ Args...>::value)
+ : impl_(in_place_index_t<I>{}, lib::forward<Args>(args)...) {}
+
+ template <
+ std::size_t I,
+ typename Up,
+ typename... Args,
+ typename T = lib::type_pack_element_t<I, Ts...>,
+ lib::enable_if_t<std::is_constructible<T,
+ std::initializer_list<Up> &,
+ Args...>::value,
+ int> = 0>
+ inline explicit constexpr variant(
+ in_place_index_t<I>,
+ std::initializer_list<Up> il,
+ Args &&... args) noexcept(std::
+ is_nothrow_constructible<
+ T,
+ std::initializer_list<Up> &,
+ Args...>::value)
+ : impl_(in_place_index_t<I>{}, il, lib::forward<Args>(args)...) {}
+
+ template <
+ typename T,
+ typename... Args,
+ std::size_t I = detail::find_index_sfinae<T, Ts...>::value,
+ lib::enable_if_t<std::is_constructible<T, Args...>::value, int> = 0>
+ inline explicit constexpr variant(
+ in_place_type_t<T>,
+ Args &&... args) noexcept(std::is_nothrow_constructible<T,
+ Args...>::value)
+ : impl_(in_place_index_t<I>{}, lib::forward<Args>(args)...) {}
+
+ template <
+ typename T,
+ typename Up,
+ typename... Args,
+ std::size_t I = detail::find_index_sfinae<T, Ts...>::value,
+ lib::enable_if_t<std::is_constructible<T,
+ std::initializer_list<Up> &,
+ Args...>::value,
+ int> = 0>
+ inline explicit constexpr variant(
+ in_place_type_t<T>,
+ std::initializer_list<Up> il,
+ Args &&... args) noexcept(std::
+ is_nothrow_constructible<
+ T,
+ std::initializer_list<Up> &,
+ Args...>::value)
+ : impl_(in_place_index_t<I>{}, il, lib::forward<Args>(args)...) {}
+
+ ~variant() = default;
+
+ variant &operator=(const variant &) = default;
+ variant &operator=(variant &&) = default;
+
+ template <typename Arg,
+ lib::enable_if_t<!std::is_same<lib::decay_t<Arg>, variant>::value,
+ int> = 0,
+ std::size_t I = detail::best_match<Arg, Ts...>::value,
+ typename T = lib::type_pack_element_t<I, Ts...>,
+ lib::enable_if_t<(std::is_assignable<T &, Arg>::value &&
+ std::is_constructible<T, Arg>::value),
+ int> = 0>
+ inline variant &operator=(Arg &&arg) noexcept(
+ (std::is_nothrow_assignable<T &, Arg>::value &&
+ std::is_nothrow_constructible<T, Arg>::value)) {
+ impl_.template assign<I>(lib::forward<Arg>(arg));
+ return *this;
+ }
+
+ template <
+ std::size_t I,
+ typename... Args,
+ typename T = lib::type_pack_element_t<I, Ts...>,
+ lib::enable_if_t<std::is_constructible<T, Args...>::value, int> = 0>
+ inline T &emplace(Args &&... args) {
+ return impl_.template emplace<I>(lib::forward<Args>(args)...);
+ }
+
+ template <
+ std::size_t I,
+ typename Up,
+ typename... Args,
+ typename T = lib::type_pack_element_t<I, Ts...>,
+ lib::enable_if_t<std::is_constructible<T,
+ std::initializer_list<Up> &,
+ Args...>::value,
+ int> = 0>
+ inline T &emplace(std::initializer_list<Up> il, Args &&... args) {
+ return impl_.template emplace<I>(il, lib::forward<Args>(args)...);
+ }
+
+ template <
+ typename T,
+ typename... Args,
+ std::size_t I = detail::find_index_sfinae<T, Ts...>::value,
+ lib::enable_if_t<std::is_constructible<T, Args...>::value, int> = 0>
+ inline T &emplace(Args &&... args) {
+ return impl_.template emplace<I>(lib::forward<Args>(args)...);
+ }
+
+ template <
+ typename T,
+ typename Up,
+ typename... Args,
+ std::size_t I = detail::find_index_sfinae<T, Ts...>::value,
+ lib::enable_if_t<std::is_constructible<T,
+ std::initializer_list<Up> &,
+ Args...>::value,
+ int> = 0>
+ inline T &emplace(std::initializer_list<Up> il, Args &&... args) {
+ return impl_.template emplace<I>(il, lib::forward<Args>(args)...);
+ }
+
+ inline constexpr bool valueless_by_exception() const noexcept {
+ return impl_.valueless_by_exception();
+ }
+
+ inline constexpr std::size_t index() const noexcept {
+ return impl_.index();
+ }
+
+ template <bool Dummy = true,
+ lib::enable_if_t<
+ lib::all<Dummy,
+ (lib::dependent_type<std::is_move_constructible<Ts>,
+ Dummy>::value &&
+ lib::dependent_type<lib::is_swappable<Ts>,
+ Dummy>::value)...>::value,
+ int> = 0>
+ inline void swap(variant &that) noexcept(
+ lib::all<(std::is_nothrow_move_constructible<Ts>::value &&
+ lib::is_nothrow_swappable<Ts>::value)...>::value) {
+ impl_.swap(that.impl_);
+ }
+
+ private:
+ detail::impl<Ts...> impl_;
+
+ friend struct detail::access::variant;
+ friend struct detail::visitation::variant;
+ };
+
+ template <std::size_t I, typename... Ts>
+ inline constexpr bool holds_alternative(const variant<Ts...> &v) noexcept {
+ return v.index() == I;
+ }
+
+ template <typename T, typename... Ts>
+ inline constexpr bool holds_alternative(const variant<Ts...> &v) noexcept {
+ return holds_alternative<detail::find_index_checked<T, Ts...>::value>(v);
+ }
+
+ namespace detail {
+ template <std::size_t I, typename V>
+ struct generic_get_impl {
+ constexpr generic_get_impl(int) {}
+
+ constexpr AUTO_REFREF operator()(V &&v) const
+ AUTO_REFREF_RETURN(
+ access::variant::get_alt<I>(lib::forward<V>(v)).value)
+ };
+
+ template <std::size_t I, typename V>
+ inline constexpr AUTO_REFREF generic_get(V &&v)
+ AUTO_REFREF_RETURN(generic_get_impl<I, V>(
+ holds_alternative<I>(v) ? 0 : (throw_bad_variant_access(), 0))(
+ lib::forward<V>(v)))
+ } // namespace detail
+
+ template <std::size_t I, typename... Ts>
+ inline constexpr variant_alternative_t<I, variant<Ts...>> &get(
+ variant<Ts...> &v) {
+ return detail::generic_get<I>(v);
+ }
+
+ template <std::size_t I, typename... Ts>
+ inline constexpr variant_alternative_t<I, variant<Ts...>> &&get(
+ variant<Ts...> &&v) {
+ return detail::generic_get<I>(lib::move(v));
+ }
+
+ template <std::size_t I, typename... Ts>
+ inline constexpr const variant_alternative_t<I, variant<Ts...>> &get(
+ const variant<Ts...> &v) {
+ return detail::generic_get<I>(v);
+ }
+
+ template <std::size_t I, typename... Ts>
+ inline constexpr const variant_alternative_t<I, variant<Ts...>> &&get(
+ const variant<Ts...> &&v) {
+ return detail::generic_get<I>(lib::move(v));
+ }
+
+ template <typename T, typename... Ts>
+ inline constexpr T &get(variant<Ts...> &v) {
+ return get<detail::find_index_checked<T, Ts...>::value>(v);
+ }
+
+ template <typename T, typename... Ts>
+ inline constexpr T &&get(variant<Ts...> &&v) {
+ return get<detail::find_index_checked<T, Ts...>::value>(lib::move(v));
+ }
+
+ template <typename T, typename... Ts>
+ inline constexpr const T &get(const variant<Ts...> &v) {
+ return get<detail::find_index_checked<T, Ts...>::value>(v);
+ }
+
+ template <typename T, typename... Ts>
+ inline constexpr const T &&get(const variant<Ts...> &&v) {
+ return get<detail::find_index_checked<T, Ts...>::value>(lib::move(v));
+ }
+
+ namespace detail {
+
+ template <std::size_t I, typename V>
+ inline constexpr /* auto * */ AUTO generic_get_if(V *v) noexcept
+ AUTO_RETURN(v && holds_alternative<I>(*v)
+ ? lib::addressof(access::variant::get_alt<I>(*v).value)
+ : nullptr)
+
+ } // namespace detail
+
+ template <std::size_t I, typename... Ts>
+ inline constexpr lib::add_pointer_t<variant_alternative_t<I, variant<Ts...>>>
+ get_if(variant<Ts...> *v) noexcept {
+ return detail::generic_get_if<I>(v);
+ }
+
+ template <std::size_t I, typename... Ts>
+ inline constexpr lib::add_pointer_t<
+ const variant_alternative_t<I, variant<Ts...>>>
+ get_if(const variant<Ts...> *v) noexcept {
+ return detail::generic_get_if<I>(v);
+ }
+
+ template <typename T, typename... Ts>
+ inline constexpr lib::add_pointer_t<T>
+ get_if(variant<Ts...> *v) noexcept {
+ return get_if<detail::find_index_checked<T, Ts...>::value>(v);
+ }
+
+ template <typename T, typename... Ts>
+ inline constexpr lib::add_pointer_t<const T>
+ get_if(const variant<Ts...> *v) noexcept {
+ return get_if<detail::find_index_checked<T, Ts...>::value>(v);
+ }
+
+ template <typename... Ts>
+ inline constexpr bool operator==(const variant<Ts...> &lhs,
+ const variant<Ts...> &rhs) {
+ using detail::visitation::variant;
+ using lib::equal_to;
+#ifdef MPARK_CPP14_CONSTEXPR
+ if (lhs.index() != rhs.index()) return false;
+ if (lhs.valueless_by_exception()) return true;
+ return variant::visit_value_at(lhs.index(), equal_to{}, lhs, rhs);
+#else
+ return lhs.index() == rhs.index() &&
+ (lhs.valueless_by_exception() ||
+ variant::visit_value_at(lhs.index(), equal_to{}, lhs, rhs));
+#endif
+ }
+
+ template <typename... Ts>
+ inline constexpr bool operator!=(const variant<Ts...> &lhs,
+ const variant<Ts...> &rhs) {
+ using detail::visitation::variant;
+ using lib::not_equal_to;
+#ifdef MPARK_CPP14_CONSTEXPR
+ if (lhs.index() != rhs.index()) return true;
+ if (lhs.valueless_by_exception()) return false;
+ return variant::visit_value_at(lhs.index(), not_equal_to{}, lhs, rhs);
+#else
+ return lhs.index() != rhs.index() ||
+ (!lhs.valueless_by_exception() &&
+ variant::visit_value_at(lhs.index(), not_equal_to{}, lhs, rhs));
+#endif
+ }
+
+ template <typename... Ts>
+ inline constexpr bool operator<(const variant<Ts...> &lhs,
+ const variant<Ts...> &rhs) {
+ using detail::visitation::variant;
+ using lib::less;
+#ifdef MPARK_CPP14_CONSTEXPR
+ if (rhs.valueless_by_exception()) return false;
+ if (lhs.valueless_by_exception()) return true;
+ if (lhs.index() < rhs.index()) return true;
+ if (lhs.index() > rhs.index()) return false;
+ return variant::visit_value_at(lhs.index(), less{}, lhs, rhs);
+#else
+ return !rhs.valueless_by_exception() &&
+ (lhs.valueless_by_exception() || lhs.index() < rhs.index() ||
+ (lhs.index() == rhs.index() &&
+ variant::visit_value_at(lhs.index(), less{}, lhs, rhs)));
+#endif
+ }
+
+ template <typename... Ts>
+ inline constexpr bool operator>(const variant<Ts...> &lhs,
+ const variant<Ts...> &rhs) {
+ using detail::visitation::variant;
+ using lib::greater;
+#ifdef MPARK_CPP14_CONSTEXPR
+ if (lhs.valueless_by_exception()) return false;
+ if (rhs.valueless_by_exception()) return true;
+ if (lhs.index() > rhs.index()) return true;
+ if (lhs.index() < rhs.index()) return false;
+ return variant::visit_value_at(lhs.index(), greater{}, lhs, rhs);
+#else
+ return !lhs.valueless_by_exception() &&
+ (rhs.valueless_by_exception() || lhs.index() > rhs.index() ||
+ (lhs.index() == rhs.index() &&
+ variant::visit_value_at(lhs.index(), greater{}, lhs, rhs)));
+#endif
+ }
+
+ template <typename... Ts>
+ inline constexpr bool operator<=(const variant<Ts...> &lhs,
+ const variant<Ts...> &rhs) {
+ using detail::visitation::variant;
+ using lib::less_equal;
+#ifdef MPARK_CPP14_CONSTEXPR
+ if (lhs.valueless_by_exception()) return true;
+ if (rhs.valueless_by_exception()) return false;
+ if (lhs.index() < rhs.index()) return true;
+ if (lhs.index() > rhs.index()) return false;
+ return variant::visit_value_at(lhs.index(), less_equal{}, lhs, rhs);
+#else
+ return lhs.valueless_by_exception() ||
+ (!rhs.valueless_by_exception() &&
+ (lhs.index() < rhs.index() ||
+ (lhs.index() == rhs.index() &&
+ variant::visit_value_at(lhs.index(), less_equal{}, lhs, rhs))));
+#endif
+ }
+
+ template <typename... Ts>
+ inline constexpr bool operator>=(const variant<Ts...> &lhs,
+ const variant<Ts...> &rhs) {
+ using detail::visitation::variant;
+ using lib::greater_equal;
+#ifdef MPARK_CPP14_CONSTEXPR
+ if (rhs.valueless_by_exception()) return true;
+ if (lhs.valueless_by_exception()) return false;
+ if (lhs.index() > rhs.index()) return true;
+ if (lhs.index() < rhs.index()) return false;
+ return variant::visit_value_at(lhs.index(), greater_equal{}, lhs, rhs);
+#else
+ return rhs.valueless_by_exception() ||
+ (!lhs.valueless_by_exception() &&
+ (lhs.index() > rhs.index() ||
+ (lhs.index() == rhs.index() &&
+ variant::visit_value_at(
+ lhs.index(), greater_equal{}, lhs, rhs))));
+#endif
+ }
+
+ struct monostate {};
+
+ inline constexpr bool operator<(monostate, monostate) noexcept {
+ return false;
+ }
+
+ inline constexpr bool operator>(monostate, monostate) noexcept {
+ return false;
+ }
+
+ inline constexpr bool operator<=(monostate, monostate) noexcept {
+ return true;
+ }
+
+ inline constexpr bool operator>=(monostate, monostate) noexcept {
+ return true;
+ }
+
+ inline constexpr bool operator==(monostate, monostate) noexcept {
+ return true;
+ }
+
+ inline constexpr bool operator!=(monostate, monostate) noexcept {
+ return false;
+ }
+
+#ifdef MPARK_CPP14_CONSTEXPR
+ namespace detail {
+
+ inline constexpr bool all(std::initializer_list<bool> bs) {
+ for (bool b : bs) {
+ if (!b) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ } // namespace detail
+
+ template <typename Visitor, typename... Vs>
+ inline constexpr decltype(auto) visit(Visitor &&visitor, Vs &&... vs) {
+ return (detail::all({!vs.valueless_by_exception()...})
+ ? (void)0
+ : throw_bad_variant_access()),
+ detail::visitation::variant::visit_value(
+ lib::forward<Visitor>(visitor), lib::forward<Vs>(vs)...);
+ }
+#else
+ namespace detail {
+
+ template <std::size_t N>
+ inline constexpr bool all_impl(const lib::array<bool, N> &bs,
+ std::size_t idx) {
+ return idx >= N || (bs[idx] && all_impl(bs, idx + 1));
+ }
+
+ template <std::size_t N>
+ inline constexpr bool all(const lib::array<bool, N> &bs) {
+ return all_impl(bs, 0);
+ }
+
+ } // namespace detail
+
+ template <typename Visitor, typename... Vs>
+ inline constexpr DECLTYPE_AUTO visit(Visitor &&visitor, Vs &&... vs)
+ DECLTYPE_AUTO_RETURN(
+ (detail::all(
+ lib::array<bool, sizeof...(Vs)>{{!vs.valueless_by_exception()...}})
+ ? (void)0
+ : throw_bad_variant_access()),
+ detail::visitation::variant::visit_value(lib::forward<Visitor>(visitor),
+ lib::forward<Vs>(vs)...))
+#endif
+
+ template <typename... Ts>
+ inline auto swap(variant<Ts...> &lhs,
+ variant<Ts...> &rhs) noexcept(noexcept(lhs.swap(rhs)))
+ -> decltype(lhs.swap(rhs)) {
+ lhs.swap(rhs);
+ }
+
+ namespace detail {
+
+ template <typename T, typename...>
+ using enabled_type = T;
+
+ namespace hash {
+
+ template <typename H, typename K>
+ constexpr bool meets_requirements() {
+ return std::is_copy_constructible<H>::value &&
+ std::is_move_constructible<H>::value &&
+ lib::is_invocable_r<std::size_t, H, const K &>::value;
+ }
+
+ template <typename K>
+ constexpr bool is_enabled() {
+ using H = std::hash<K>;
+ return meets_requirements<H, K>() &&
+ std::is_default_constructible<H>::value &&
+ std::is_copy_assignable<H>::value &&
+ std::is_move_assignable<H>::value;
+ }
+
+ } // namespace hash
+
+ } // namespace detail
+
+#undef AUTO
+#undef AUTO_RETURN
+
+#undef AUTO_REFREF
+#undef AUTO_REFREF_RETURN
+
+#undef DECLTYPE_AUTO
+#undef DECLTYPE_AUTO_RETURN
+
+} // namespace mpark
+
+namespace std {
+
+ template <typename... Ts>
+ struct hash<mpark::detail::enabled_type<
+ mpark::variant<Ts...>,
+ mpark::lib::enable_if_t<mpark::lib::all<mpark::detail::hash::is_enabled<
+ mpark::lib::remove_const_t<Ts>>()...>::value>>> {
+ using argument_type = mpark::variant<Ts...>;
+ using result_type = std::size_t;
+
+ inline result_type operator()(const argument_type &v) const {
+ using mpark::detail::visitation::variant;
+ std::size_t result =
+ v.valueless_by_exception()
+ ? 299792458 // Random value chosen by the universe upon creation
+ : variant::visit_alt(
+#ifdef MPARK_GENERIC_LAMBDAS
+ [](const auto &alt) {
+ using alt_type = mpark::lib::decay_t<decltype(alt)>;
+ using value_type = mpark::lib::remove_const_t<
+ typename alt_type::value_type>;
+ return hash<value_type>{}(alt.value);
+ }
+#else
+ hasher{}
+#endif
+ ,
+ v);
+ return hash_combine(result, hash<std::size_t>{}(v.index()));
+ }
+
+ private:
+#ifndef MPARK_GENERIC_LAMBDAS
+ struct hasher {
+ template <typename Alt>
+ inline std::size_t operator()(const Alt &alt) const {
+ using alt_type = mpark::lib::decay_t<Alt>;
+ using value_type =
+ mpark::lib::remove_const_t<typename alt_type::value_type>;
+ return hash<value_type>{}(alt.value);
+ }
+ };
+#endif
+
+ static std::size_t hash_combine(std::size_t lhs, std::size_t rhs) {
+ return lhs ^= rhs + 0x9e3779b9 + (lhs << 6) + (lhs >> 2);
+ }
+ };
+
+ template <>
+ struct hash<mpark::monostate> {
+ using argument_type = mpark::monostate;
+ using result_type = std::size_t;
+
+ inline result_type operator()(const argument_type &) const noexcept {
+ return 66740831; // return a fundamentally attractive random value.
+ }
+ };
+
+} // namespace std
+
+#endif // MPARK_VARIANT_HPP