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Diffstat (limited to 'depedencies/include/mpark/variant.hpp')
| -rw-r--r-- | depedencies/include/mpark/variant.hpp | 1827 |
1 files changed, 1827 insertions, 0 deletions
diff --git a/depedencies/include/mpark/variant.hpp b/depedencies/include/mpark/variant.hpp new file mode 100644 index 0000000..3faecba --- /dev/null +++ b/depedencies/include/mpark/variant.hpp @@ -0,0 +1,1827 @@ +// 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> + +#include "config.hpp" +#include "in_place.hpp" +#include "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(); +#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 { + + inline constexpr bool all() { return true; } + + template <typename... Bs> + inline constexpr bool all(bool b, Bs... bs) { + return b && all(bs...); + } + + 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 { + private: + 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(all(std::is_same<F, Fs>::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( + all((lib::decay_t<V>::size() == lib::decay_t<Vs>::size())...), + "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, std::size_t... Is> + inline static constexpr auto make_fmatrix_impl( + lib::index_sequence<Is...> is) { + return make_dispatch<F, Vs...>(is); + } + + template <typename F, + typename... Vs, + std::size_t... Is, + std::size_t... Js, + typename... Ls> + inline static constexpr auto make_fmatrix_impl( + lib::index_sequence<Is...>, lib::index_sequence<Js...>, Ls... ls) { + return make_farray(make_fmatrix_impl<F, Vs...>( + lib::index_sequence<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 <std::size_t... Is> + struct impl<lib::index_sequence<Is...>> { + inline constexpr AUTO operator()() const + AUTO_RETURN( + make_dispatch<F, Vs...>(lib::index_sequence<Is...>{})) + }; + + template <std::size_t... Is, std::size_t... Js, typename... Ls> + struct impl<lib::index_sequence<Is...>, + lib::index_sequence<Js...>, + Ls...> { + inline constexpr AUTO operator()() const + AUTO_RETURN(make_farray( + impl<lib::index_sequence<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 + + 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( + at(make_fdiagonal<Visitor &&, + decltype(as_base(lib::forward<Vs>(vs)))...>(), + 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( + at(make_fmatrix<Visitor &&, + decltype(as_base(lib::forward<Vs>(vs)))...>(), + 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( + base::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(base::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::base::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::base::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( + all(std::is_nothrow_move_constructible<Ts>::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::base::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( + all((std::is_nothrow_move_constructible<Ts>::value && + std::is_nothrow_move_assignable<Ts>::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::base::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 <typename... Ts> + struct overload; + + template <> + struct overload<> { void operator()() const {} }; + + template <typename T, typename... Ts> + struct overload<T, Ts...> : overload<Ts...> { + using overload<Ts...>::operator(); + lib::identity<T> operator()(T) const { return {}; } + }; + + template <typename T, typename... Ts> + using best_match_t = + typename lib::invoke_result_t<overload<Ts...>, T &&>::type; + + 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, + typename T = detail::best_match_t<Arg, Ts...>, + std::size_t I = detail::find_index_sfinae<T, Ts...>::value, + 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, + typename T = detail::best_match_t<Arg, Ts...>, + std::size_t I = detail::find_index_sfinae<T, Ts...>::value, + 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, + (std::is_move_constructible<Ts>::value && + lib::is_swappable<Ts>::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 + } + + template <typename Visitor, typename... Vs> + inline constexpr DECLTYPE_AUTO visit(Visitor &&visitor, Vs &&... vs) + DECLTYPE_AUTO_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)...)) + + 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; + } + + 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 |