// Copyright 2017 Dolphin Emulator Project // Licensed under GPLv2+ // Refer to the license.txt file included. #pragma once #if __cplusplus >= 201703L && __has_include_next() #include_next #else // 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) /* variant synopsis namespace std { // 20.7.2, class template variant template class variant { public: // 20.7.2.1, constructors constexpr variant() noexcept(see below); variant(const variant&); variant(variant&&) noexcept(see below); template constexpr variant(T&&) noexcept(see below); template constexpr explicit variant(::std::in_place_type_t, Args&&...); template constexpr explicit variant( ::std::in_place_type_t, initializer_list, Args&&...); template constexpr explicit variant(::std::in_place_index_t, Args&&...); template constexpr explicit variant( ::std::in_place_index_t, initializer_list, Args&&...); // 20.7.2.2, destructor ~variant(); // 20.7.2.3, assignment variant& operator=(const variant&); variant& operator=(variant&&) noexcept(see below); template variant& operator=(T&&) noexcept(see below); // 20.7.2.4, modifiers template T& emplace(Args&&...); template T& emplace(initializer_list, Args&&...); template variant_alternative& emplace(Args&&...); template variant_alternative& emplace(initializer_list, 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 struct variant_size; // undefined template constexpr size_t variant_size_v = variant_size::value; template struct variant_size; template struct variant_size; template struct variant_size; template struct variant_size>; template struct variant_alternative; // undefined template using variant_alternative_t = typename variant_alternative::type; template struct variant_alternative; template struct variant_alternative; template struct variant_alternative; template struct variant_alternative>; constexpr size_t variant_npos = -1; // 20.7.4, value access template constexpr bool holds_alternative(const variant&) noexcept; template constexpr variant_alternative_t>& get(variant&); template constexpr variant_alternative_t>&& get(variant&&); template constexpr variant_alternative_t> const& get(const variant&); template constexpr variant_alternative_t> const&& get(const variant&&); template constexpr T& get(variant&); template constexpr T&& get(variant&&); template constexpr const T& get(const variant&); template constexpr const T&& get(const variant&&); template constexpr add_pointer_t>> get_if(variant*) noexcept; template constexpr add_pointer_t>> get_if(const variant*) noexcept; template constexpr add_pointer_t get_if(variant*) noexcept; template constexpr add_pointer_t get_if(const variant*) noexcept; // 20.7.5, relational operators template constexpr bool operator==(const variant&, const variant&); template constexpr bool operator!=(const variant&, const variant&); template constexpr bool operator<(const variant&, const variant&); template constexpr bool operator>(const variant&, const variant&); template constexpr bool operator<=(const variant&, const variant&); template constexpr bool operator>=(const variant&, const variant&); // 20.7.6, visitation template 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 void swap(variant&, variant&) noexcept(see below); // 20.7.10, class bad_variant_access class bad_variant_access; // 20.7.11, hash support template struct hash; template struct hash>; template <> struct hash; } // namespace std */ #include #include #include #include #include #include #include #include "in_place.h" // 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 < 190024215) #error "MPark.Variant requires C++11 support." #endif #ifndef __has_builtin #define __has_builtin(x) 0 #endif #ifndef __has_feature #define __has_feature(x) 0 #endif #if __has_builtin(__builtin_addressof) || __GNUC__ >= 7 || defined(_MSC_VER) #define MPARK_BUILTIN_ADDRESSOF #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) #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 #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_LIB_HPP #define MPARK_LIB_HPP #include #include #include #include #define RETURN(...) \ noexcept(noexcept(__VA_ARGS__))->decltype(__VA_ARGS__) { return __VA_ARGS__; } namespace mpark { namespace lib { template struct identity { using type = T; }; inline namespace cpp14 { template struct array { constexpr const T& operator[](std::size_t index) const { return data[index]; } T data[N == 0 ? 1 : N]; }; template using add_pointer_t = typename std::add_pointer::type; template using common_type_t = typename std::common_type::type; template using decay_t = typename std::decay::type; template using enable_if_t = typename std::enable_if::type; template using remove_const_t = typename std::remove_const::type; template using remove_reference_t = typename std::remove_reference::type; template inline constexpr T&& forward(remove_reference_t& t) noexcept { return static_cast(t); } template inline constexpr T&& forward(remove_reference_t&& t) noexcept { static_assert(!std::is_lvalue_reference::value, "can not forward an rvalue as an lvalue"); return static_cast(t); } template constexpr remove_reference_t&& move(T&& t) noexcept { return static_cast&&>(t); } #ifdef MPARK_INTEGER_SEQUENCE template using integer_sequence = std::integer_sequence; template using index_sequence = std::index_sequence; template using make_index_sequence = std::make_index_sequence; template using index_sequence_for = std::index_sequence_for; #else template struct integer_sequence { using value_type = T; static constexpr std::size_t size() noexcept { return sizeof...(Is); } }; template using index_sequence = integer_sequence; template struct make_index_sequence_concat; template struct make_index_sequence_concat, index_sequence> : identity> { }; template struct make_index_sequence_impl; template using make_index_sequence = typename make_index_sequence_impl::type; template struct make_index_sequence_impl : make_index_sequence_concat, make_index_sequence> { }; template <> struct make_index_sequence_impl<0> : identity> { }; template <> struct make_index_sequence_impl<1> : identity> { }; template using index_sequence_for = make_index_sequence; #endif // #ifdef MPARK_TRANSPARENT_OPERATORS using equal_to = std::equal_to<>; #else struct equal_to { template inline constexpr auto operator()(Lhs&& lhs, Rhs&& rhs) const RETURN(lib::forward(lhs) == lib::forward(rhs)) }; #endif #ifdef MPARK_TRANSPARENT_OPERATORS using not_equal_to = std::not_equal_to<>; #else struct not_equal_to { template inline constexpr auto operator()(Lhs&& lhs, Rhs&& rhs) const RETURN(lib::forward(lhs) != lib::forward(rhs)) }; #endif #ifdef MPARK_TRANSPARENT_OPERATORS using less = std::less<>; #else struct less { template inline constexpr auto operator()(Lhs&& lhs, Rhs&& rhs) const RETURN(lib::forward(lhs) < lib::forward(rhs)) }; #endif #ifdef MPARK_TRANSPARENT_OPERATORS using greater = std::greater<>; #else struct greater { template inline constexpr auto operator()(Lhs&& lhs, Rhs&& rhs) const RETURN(lib::forward(lhs) > lib::forward(rhs)) }; #endif #ifdef MPARK_TRANSPARENT_OPERATORS using less_equal = std::less_equal<>; #else struct less_equal { template inline constexpr auto operator()(Lhs&& lhs, Rhs&& rhs) const RETURN(lib::forward(lhs) <= lib::forward(rhs)) }; #endif #ifdef MPARK_TRANSPARENT_OPERATORS using greater_equal = std::greater_equal<>; #else struct greater_equal { template inline constexpr auto operator()(Lhs&& lhs, Rhs&& rhs) const RETURN(lib::forward(lhs) >= lib::forward(rhs)) }; #endif } // namespace cpp14 inline namespace cpp17 { // template using bool_constant = std::integral_constant; template using void_t = void; namespace detail { namespace swappable { using std::swap; template struct is_swappable_impl { private: template (), std::declval()))> inline static std::true_type test(int); template inline static std::false_type test(...); public: using type = decltype(test(0)); }; template using is_swappable = typename is_swappable_impl::type; template ::value> struct is_nothrow_swappable { static constexpr bool value = noexcept(swap(std::declval(), std::declval())); }; template struct is_nothrow_swappable : std::false_type { }; } // namespace swappable } // namespace detail template using is_swappable = detail::swappable::is_swappable; template using is_nothrow_swappable = detail::swappable::is_nothrow_swappable; // #ifdef _MSC_VER #pragma warning(push) #pragma warning(disable : 4100) #endif template inline constexpr auto invoke(F&& f, As&&... as) RETURN(lib::forward(f)(lib::forward(as)...)) #ifdef _MSC_VER #pragma warning(pop) #endif template inline constexpr auto invoke(T B::*pmv, D&& d) RETURN(lib::forward(d).*pmv) template inline constexpr auto invoke(Pmv pmv, Ptr&& ptr) RETURN((*lib::forward(ptr)).*pmv) template inline constexpr auto invoke(T B::*pmf, D&& d, As&&... as) RETURN((lib::forward(d).*pmf)(lib::forward(as)...)) template inline constexpr auto invoke(Pmf pmf, Ptr&& ptr, As&&... as) RETURN(((*lib::forward(ptr)).*pmf)(lib::forward(as)...)) namespace detail { template struct invoke_result { }; template struct invoke_result(), std::declval()...))>, F, Args...> : identity(), std::declval()...))> { }; } // namespace detail template using invoke_result = detail::invoke_result; template using invoke_result_t = typename invoke_result::type; namespace detail { template struct is_invocable : std::false_type { }; template struct is_invocable>, F, Args...> : std::true_type { }; template struct is_invocable_r : std::false_type { }; template struct is_invocable_r>, R, F, Args...> : std::is_convertible, R> { }; } // namespace detail template using is_invocable = detail::is_invocable; template using is_invocable_r = detail::is_invocable_r; // #ifdef MPARK_BUILTIN_ADDRESSOF template inline constexpr T* addressof(T& arg) { return __builtin_addressof(arg); } #else namespace detail { namespace has_addressof_impl { struct fail; template inline fail operator&(T&&); template inline static constexpr bool impl() { return (std::is_class::value || std::is_union::value) && !std::is_same()), fail>::value; } } // namespace has_addressof_impl template using has_addressof = bool_constant()>; template inline constexpr T* addressof(T& arg, std::true_type) { return std::addressof(arg); } template inline constexpr T* addressof(T& arg, std::false_type) { return &arg; } } // namespace detail template inline constexpr T* addressof(T& arg) { return detail::addressof(arg, detail::has_addressof{}); } #endif template inline constexpr T* addressof(const T&&) = delete; } // namespace cpp17 template struct remove_all_extents : identity { }; template struct remove_all_extents> : remove_all_extents { }; template using remove_all_extents_t = typename remove_all_extents::type; template using size_constant = std::integral_constant; template using bool_sequence = integer_sequence; template struct indexed_type : size_constant, identity { }; template using all = std::is_same, bool_sequence>; #ifdef MPARK_TYPE_PACK_ELEMENT template using type_pack_element_t = __type_pack_element; #else template struct type_pack_element_impl { private: template struct set; template struct set> : indexed_type... { }; template inline static std::enable_if impl(indexed_type); inline static std::enable_if impl(...); public: using type = decltype(impl(set>{})); }; template using type_pack_element = typename type_pack_element_impl::type; template using type_pack_element_t = typename type_pack_element::type; #endif } // 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 { return __VA_ARGS__; } #define AUTO_REFREF auto #define AUTO_REFREF_RETURN(...) \ ->decltype((__VA_ARGS__)) \ { \ static_assert(std::is_reference::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 class variant; template struct variant_size; #ifdef MPARK_VARIABLE_TEMPLATES template constexpr std::size_t variant_size_v = variant_size::value; #endif template struct variant_size : variant_size { }; template struct variant_size : variant_size { }; template struct variant_size : variant_size { }; template struct variant_size> : lib::size_constant { }; template struct variant_alternative; template using variant_alternative_t = typename variant_alternative::type; template struct variant_alternative : std::add_const> { }; template struct variant_alternative : std::add_volatile> { }; template struct variant_alternative : std::add_cv> { }; template struct variant_alternative> : lib::identity> { static_assert(I < sizeof...(Ts), "`variant_alternative` index out of range."); }; constexpr std::size_t variant_npos = static_cast(-1); namespace detail { inline constexpr bool all() { return true; } template inline constexpr bool all(bool b, Bs... bs) { return b && all(bs...); } constexpr std::size_t not_found = static_cast(-1); constexpr std::size_t ambiguous = static_cast(-2); #ifdef MPARK_CPP14_CONSTEXPR template inline constexpr std::size_t find_index() { constexpr lib::array matches = {{std::is_same::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 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 inline constexpr std::size_t find_index() { return find_index_impl(not_found, 0, std::is_same::value...); } #endif template using find_index_sfinae_impl = lib::enable_if_t>; template using find_index_sfinae = find_index_sfinae_impl()>; template struct find_index_checked_impl : lib::size_constant { static_assert(I != not_found, "the specified type is not found."); static_assert(I != ambiguous, "the specified type is ambiguous."); }; template using find_index_checked = find_index_checked_impl()>; struct valueless_t { }; enum class Trait { TriviallyAvailable, Available, Unavailable }; template class IsTriviallyAvailable, template class IsAvailable> inline constexpr Trait trait() { return IsTriviallyAvailable::value ? Trait::TriviallyAvailable : IsAvailable::value ? Trait::Available : Trait::Unavailable; } #ifdef MPARK_CPP14_CONSTEXPR template inline constexpr Trait common_trait(Traits... traits) { Trait result = Trait::TriviallyAvailable; for (Trait t : {traits...}) { if (static_cast(t) > static_cast(result)) { result = t; } } return result; } #else inline constexpr Trait common_trait_impl(Trait result) { return result; } template inline constexpr Trait common_trait_impl(Trait result, Trait t, Traits... ts) { return static_cast(t) > static_cast(result) ? common_trait_impl(t, ts...) : common_trait_impl(result, ts...); } template inline constexpr Trait common_trait(Traits... ts) { return common_trait_impl(Trait::TriviallyAvailable, ts...); } #endif template struct traits { static constexpr Trait copy_constructible_trait = common_trait( trait()...); static constexpr Trait move_constructible_trait = common_trait( trait()...); static constexpr Trait copy_assignable_trait = common_trait(copy_constructible_trait, move_constructible_trait, trait()...); static constexpr Trait move_assignable_trait = common_trait(move_constructible_trait, trait()...); static constexpr Trait destructible_trait = common_trait(trait()...); }; namespace access { struct recursive_union { #ifdef MPARK_RETURN_TYPE_DEDUCTION template inline static constexpr auto&& get_alt(V&& v, ::std::in_place_index_t<0>) { return lib::forward(v).head_; } template inline static constexpr auto&& get_alt(V&& v, ::std::in_place_index_t) { return get_alt(lib::forward(v).tail_, ::std::in_place_index_t{}); } #else template struct get_alt_impl { template inline constexpr AUTO_REFREF operator()(V&& v) const AUTO_REFREF_RETURN(get_alt_impl{}(lib::forward(v).tail_)) }; template struct get_alt_impl<0, Dummy> { template inline constexpr AUTO_REFREF operator()(V&& v) const AUTO_REFREF_RETURN(lib::forward(v).head_) }; template inline static constexpr AUTO_REFREF get_alt(V&& v, ::std::in_place_index_t) AUTO_REFREF_RETURN(get_alt_impl{}(lib::forward(v))) #endif }; struct base { template inline static constexpr AUTO_REFREF get_alt(V&& v) AUTO_REFREF_RETURN(recursive_union::get_alt(lib::forward(v).data_, ::std::in_place_index_t{})) }; struct variant { template inline static constexpr AUTO_REFREF get_alt(V&& v) AUTO_REFREF_RETURN(base::get_alt(lib::forward(v).impl_)) }; } // namespace access namespace visitation { struct base { private: template inline static constexpr const T& at(const T& elem) { return elem; } template inline static constexpr const lib::remove_all_extents_t& at(const lib::array& elems, std::size_t i, Is... is) { return at(elems[i], is...); } template inline static constexpr int visit_visitor_return_type_check() { static_assert(all(std::is_same::value...), "`mpark::visit` requires the visitor to have a single " "return type."); return 0; } template inline static constexpr lib::array...>, sizeof...(Fs)> make_farray(Fs&&... fs) { using result = lib::array...>, sizeof...(Fs)>; return visit_visitor_return_type_check...>(), result{{lib::forward(fs)...}}; } template struct dispatcher { template struct impl { inline static constexpr DECLTYPE_AUTO dispatch(F f, Vs... vs) DECLTYPE_AUTO_RETURN(lib::invoke(static_cast(f), access::base::get_alt(static_cast(vs))...)) }; }; template inline static constexpr AUTO make_dispatch(lib::index_sequence) AUTO_RETURN(&dispatcher::template impl::dispatch) template inline static constexpr AUTO make_fdiagonal_impl() AUTO_RETURN( make_dispatch(lib::index_sequence::value...>{})) template inline static constexpr AUTO make_fdiagonal_impl(lib::index_sequence) AUTO_RETURN(make_farray(make_fdiagonal_impl()...)) template inline static constexpr /* auto * */ auto make_fdiagonal() -> decltype(make_fdiagonal_impl( lib::make_index_sequence::size()>{})) { static_assert(all((lib::decay_t::size() == lib::decay_t::size())...), "all of the variants must be the same size."); return make_fdiagonal_impl(lib::make_index_sequence::size()>{}); } #ifdef MPARK_RETURN_TYPE_DEDUCTION template inline static constexpr auto make_fmatrix_impl(lib::index_sequence is) { return make_dispatch(is); } template inline static constexpr auto make_fmatrix_impl(lib::index_sequence, lib::index_sequence, Ls... ls) { return make_farray(make_fmatrix_impl(lib::index_sequence{}, ls...)...); } template inline static constexpr auto make_fmatrix() { return make_fmatrix_impl(lib::index_sequence<>{}, lib::make_index_sequence::size()>{}...); } #else template struct make_fmatrix_impl { template struct impl; template struct impl> { inline constexpr AUTO operator()() const AUTO_RETURN(make_dispatch(lib::index_sequence{})) }; template struct impl, lib::index_sequence, Ls...> { inline constexpr AUTO operator()() const AUTO_RETURN(make_farray(impl, Ls...>{}()...)) }; }; template inline static constexpr AUTO make_fmatrix() AUTO_RETURN( typename make_fmatrix_impl::template impl< lib::index_sequence<>, lib::make_index_sequence::size()>...>{}()) #endif public: template inline static constexpr DECLTYPE_AUTO visit_alt_at(std::size_t index, Visitor&& visitor, Vs&&... vs) DECLTYPE_AUTO_RETURN( at(make_fdiagonal(vs)))...>(), index)(lib::forward(visitor), as_base(lib::forward(vs))...)) template inline static constexpr DECLTYPE_AUTO visit_alt(Visitor&& visitor, Vs&&... vs) DECLTYPE_AUTO_RETURN( at(make_fmatrix(vs)))...>(), vs.index()...)(lib::forward(visitor), as_base(lib::forward(vs))...)) }; struct variant { private: template struct visit_exhaustive_visitor_check { static_assert(lib::is_invocable::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), lib::forward(values)...)) #ifdef _MSC_VER #pragma warning(pop) #endif }; template struct value_visitor { Visitor&& visitor_; template inline constexpr DECLTYPE_AUTO operator()(Alts&&... alts) const DECLTYPE_AUTO_RETURN( visit_exhaustive_visitor_check(alts).value))...>{}( lib::forward(visitor_), lib::forward(alts).value...)) }; template inline static constexpr AUTO make_value_visitor(Visitor&& visitor) AUTO_RETURN(value_visitor{lib::forward(visitor)}) public : template 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), lib::forward(vs).impl_...)) template inline static constexpr DECLTYPE_AUTO visit_alt(Visitor&& visitor, Vs&&... vs) DECLTYPE_AUTO_RETURN(base::visit_alt(lib::forward(visitor), lib::forward(vs).impl_...)) template 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)), lib::forward(vs)...)) template inline static constexpr DECLTYPE_AUTO visit_value(Visitor&& visitor, Vs&&... vs) DECLTYPE_AUTO_RETURN(visit_alt(make_value_visitor(lib::forward(visitor)), lib::forward(vs)...)) }; } // namespace visitation template struct alt { using value_type = T; #ifdef _MSC_VER #pragma warning(push) #pragma warning(disable : 4244) #endif template inline explicit constexpr alt(::std::in_place_t, Args&&... args) : value(lib::forward(args)...) { } #ifdef _MSC_VER #pragma warning(pop) #endif T value; }; template union recursive_union; template union recursive_union { }; #define MPARK_VARIANT_RECURSIVE_UNION(destructible_trait, destructor) \ template \ union recursive_union \ { \ public: \ inline explicit constexpr recursive_union(valueless_t) noexcept : dummy_{} {} \ template \ inline explicit constexpr recursive_union(::std::in_place_index_t<0>, Args&&... args) \ : head_(::std::in_place_t{}, lib::forward(args)...) \ { \ } \ \ template \ inline explicit constexpr recursive_union(::std::in_place_index_t, Args&&... args) \ : tail_(::std::in_place_index_t{}, lib::forward(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 head_; \ recursive_union 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 class base { public: inline explicit constexpr base(valueless_t tag) noexcept : data_(tag), index_(static_cast(-1)) { } template inline explicit constexpr base(::std::in_place_index_t, Args&&... args) : data_(::std::in_place_index_t{}, lib::forward(args)...), index_(I) { } inline constexpr bool valueless_by_exception() const noexcept { return index_ == static_cast(-1); } inline constexpr std::size_t index() const noexcept { return valueless_by_exception() ? variant_npos : index_; } protected: 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); } inline static constexpr std::size_t size() { return sizeof...(Ts); } recursive_union 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 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 \ inline explicit constexpr type(Args&&... args) : base(lib::forward(args)...) \ { \ } #else #define INHERITING_CTOR(type, base) using base::base; #endif template class destructor; #define MPARK_VARIANT_DESTRUCTOR(destructible_trait, definition, destroy) \ template \ class destructor, destructible_trait> : public base \ { \ using super = base; \ \ 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(-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(-1); }); MPARK_VARIANT_DESTRUCTOR(Trait::Unavailable, ~destructor() = delete; , inline void destroy() noexcept = delete;); #undef MPARK_VARIANT_DESTRUCTOR template class constructor : public destructor { using super = destructor; public: INHERITING_CTOR(constructor, super) using super::operator=; protected: #ifndef MPARK_GENERIC_LAMBDAS struct ctor { template inline void operator()(LhsAlt& lhs_alt, RhsAlt&& rhs_alt) const { constructor::construct_alt(lhs_alt, lib::forward(rhs_alt).value); } }; #endif template inline static T& construct_alt(alt& a, Args&&... args) { ::new (static_cast(lib::addressof(a))) alt(::std::in_place_t{}, lib::forward(args)...); return a.value; } template 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(rhs_alt).value); } #else ctor {} #endif , lhs, lib::forward(rhs)); lhs.index_ = rhs.index_; } } }; template class move_constructor; #define MPARK_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, definition) \ template \ class move_constructor, move_constructible_trait> \ : public constructor> \ { \ using super = constructor>; \ \ 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::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 class copy_constructor; #define MPARK_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, definition) \ template \ class copy_constructor, copy_constructible_trait> \ : public move_constructor> \ { \ using super = move_constructor>; \ \ 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 class assignment : public copy_constructor { using super = copy_constructor; public: INHERITING_CTOR(assignment, super) using super::operator=; template inline /* auto & */ auto emplace(Args&&... args) -> decltype(this->construct_alt(access::base::get_alt(*this), lib::forward(args)...)) { this->destroy(); auto& result = this->construct_alt(access::base::get_alt(*this), lib::forward(args)...); this->index_ = I; return result; } protected: #ifndef MPARK_GENERIC_LAMBDAS template struct assigner { template inline void operator()(ThisAlt& this_alt, ThatAlt&& that_alt) const { self->assign_alt(this_alt, lib::forward(that_alt).value, std::is_lvalue_reference{}); } assignment* self; }; #endif template inline void assign_alt(alt& a, Arg&& arg, lib::bool_constant tag) { if (this->index() == I) { #ifdef _MSC_VER #pragma warning(push) #pragma warning(disable : 4244) #endif a.value = lib::forward(arg); #ifdef _MSC_VER #pragma warning(pop) #endif } else { struct { void operator()(std::true_type) const { this_->emplace(T(lib::forward(arg_))); } void operator()(std::false_type) const { this_->emplace(lib::forward(arg_)); } assignment* this_; Arg&& arg_; } impl{this, lib::forward(arg)}; impl(tag); } } template 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(that_alt).value, std::is_lvalue_reference{}); } #else assigner { this } #endif , *this, lib::forward(that)); } } }; template class move_assignment; #define MPARK_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, definition) \ template \ class move_assignment, move_assignable_trait> : public assignment> \ { \ using super = assignment>; \ \ 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::value && std::is_nothrow_move_assignable::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 class copy_assignment; #define MPARK_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait, definition) \ template \ class copy_assignment, copy_assignable_trait> \ : public move_assignment> \ { \ using super = move_assignment>; \ \ 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 class impl : public copy_assignment> { using super = copy_assignment>; public: INHERITING_CTOR(impl, super) using super::operator=; template inline void assign(Arg&& arg) { this->assign_alt(access::base::get_alt(*this), lib::forward(arg), std::false_type{}); } 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 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{ {std::is_nothrow_move_constructible::value...}}[this->index()]; } }; template struct overload; template <> struct overload<> { void operator()() const {} }; template struct overload : overload { using overload::operator(); lib::identity operator()(T) const { return {}; } }; template using best_match_t = typename lib::invoke_result_t, T&&>::type; } // detail template class variant { static_assert(0 < sizeof...(Ts), "variant must consist of at least one alternative."); static_assert(lib::all::value...>::value, "variant can not have an array type as an alternative."); static_assert(lib::all::value...>::value, "variant can not have a reference type as an alternative."); static_assert(lib::all::value...>::value, "variant can not have a void type as an alternative."); public: template , lib::enable_if_t::value, int> = 0> inline constexpr variant() noexcept(std::is_nothrow_default_constructible::value) : impl_(::std::in_place_index_t<0>{}) { } variant(const variant&) = default; variant(variant&&) = default; template , variant>::value, int> = 0, typename T = detail::best_match_t, std::size_t I = detail::find_index_sfinae::value, lib::enable_if_t::value, int> = 0> inline constexpr variant(Arg&& arg) noexcept(std::is_nothrow_constructible::value) : impl_(::std::in_place_index_t{}, lib::forward(arg)) { } template , lib::enable_if_t::value, int> = 0> inline explicit constexpr variant(::std::in_place_index_t, Args&&... args) noexcept( std::is_nothrow_constructible::value) : impl_(::std::in_place_index_t{}, lib::forward(args)...) { } template , lib::enable_if_t&, Args...>::value, int> = 0> inline explicit constexpr variant( ::std::in_place_index_t, std::initializer_list il, Args&&... args) noexcept(std::is_nothrow_constructible&, Args...>::value) : impl_(::std::in_place_index_t{}, il, lib::forward(args)...) { } template ::value, lib::enable_if_t::value, int> = 0> inline explicit constexpr variant(::std::in_place_type_t, Args&&... args) noexcept( std::is_nothrow_constructible::value) : impl_(::std::in_place_index_t{}, lib::forward(args)...) { } template ::value, lib::enable_if_t&, Args...>::value, int> = 0> inline explicit constexpr variant( ::std::in_place_type_t, std::initializer_list il, Args&&... args) noexcept(std::is_nothrow_constructible&, Args...>::value) : impl_(::std::in_place_index_t{}, il, lib::forward(args)...) { } ~variant() = default; variant& operator=(const variant&) = default; variant& operator=(variant&&) = default; template < typename Arg, lib::enable_if_t, variant>::value, int> = 0, typename T = detail::best_match_t, std::size_t I = detail::find_index_sfinae::value, lib::enable_if_t<(std::is_assignable::value && std::is_constructible::value), int> = 0> inline variant& operator=(Arg&& arg) noexcept((std::is_nothrow_assignable::value && std::is_nothrow_constructible::value)) { impl_.template assign(lib::forward(arg)); return *this; } template , lib::enable_if_t::value, int> = 0> inline T& emplace(Args&&... args) { return impl_.template emplace(lib::forward(args)...); } template , lib::enable_if_t&, Args...>::value, int> = 0> inline T& emplace(std::initializer_list il, Args&&... args) { return impl_.template emplace(il, lib::forward(args)...); } template ::value, lib::enable_if_t::value, int> = 0> inline T& emplace(Args&&... args) { return impl_.template emplace(lib::forward(args)...); } template ::value, lib::enable_if_t&, Args...>::value, int> = 0> inline T& emplace(std::initializer_list il, Args&&... args) { return impl_.template emplace(il, lib::forward(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 ::value && lib::is_swappable::value)...>::value, int> = 0> inline void swap(variant& that) noexcept(lib::all<(std::is_nothrow_move_constructible::value && lib::is_nothrow_swappable::value)...>::value) { impl_.swap(that.impl_); } private: detail::impl impl_; friend struct detail::access::variant; friend struct detail::visitation::variant; }; template inline constexpr bool holds_alternative(const variant& v) noexcept { return v.index() == I; } template inline constexpr bool holds_alternative(const variant& v) noexcept { return holds_alternative::value>(v); } namespace detail { template struct generic_get_impl { constexpr generic_get_impl(int) {} constexpr AUTO_REFREF operator()(V&& v) const AUTO_REFREF_RETURN(access::variant::get_alt(lib::forward(v)).value) }; template inline constexpr AUTO_REFREF generic_get(V&& v) AUTO_REFREF_RETURN(generic_get_impl( holds_alternative(v) ? 0 : (throw_bad_variant_access(), 0))(lib::forward(v))) } // namespace detail template inline constexpr variant_alternative_t>& get(variant& v) { return detail::generic_get(v); } template inline constexpr variant_alternative_t>&& get(variant&& v) { return detail::generic_get(lib::move(v)); } template inline constexpr const variant_alternative_t>& get(const variant& v) { return detail::generic_get(v); } template inline constexpr const variant_alternative_t>&& get(const variant&& v) { return detail::generic_get(lib::move(v)); } template inline constexpr T& get(variant& v) { return get::value>(v); } template inline constexpr T&& get(variant&& v) { return get::value>(lib::move(v)); } template inline constexpr const T& get(const variant& v) { return get::value>(v); } template inline constexpr const T&& get(const variant&& v) { return get::value>(lib::move(v)); } namespace detail { template inline constexpr /* auto * */ AUTO generic_get_if(V* v) noexcept AUTO_RETURN( v&& holds_alternative(*v) ? lib::addressof(access::variant::get_alt(*v).value) : nullptr) } // namespace detail template inline constexpr lib::add_pointer_t>> get_if(variant* v) noexcept { return detail::generic_get_if(v); } template inline constexpr lib::add_pointer_t>> get_if(const variant* v) noexcept { return detail::generic_get_if(v); } template inline constexpr lib::add_pointer_t get_if(variant* v) noexcept { return get_if::value>(v); } template inline constexpr lib::add_pointer_t get_if(const variant* v) noexcept { return get_if::value>(v); } template inline constexpr bool operator==(const variant& lhs, const variant& 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 inline constexpr bool operator!=(const variant& lhs, const variant& 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 inline constexpr bool operator<(const variant& lhs, const variant& 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 inline constexpr bool operator>(const variant& lhs, const variant& 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 inline constexpr bool operator<=(const variant& lhs, const variant& 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 inline constexpr bool operator>=(const variant& lhs, const variant& 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 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), lib::forward(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 inline auto swap(variant& lhs, variant& rhs) noexcept(noexcept(lhs.swap(rhs))) -> decltype(lhs.swap(rhs)) { lhs.swap(rhs); } namespace detail { template using enabled_type = T; namespace hash { template constexpr bool meets_requirements() { return std::is_copy_constructible::value && std::is_move_constructible::value && lib::is_invocable_r::value; } template constexpr bool is_enabled() { using H = std::hash; return meets_requirements() && std::is_default_constructible::value && std::is_copy_assignable::value && std::is_move_assignable::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 struct hash, mpark::lib::enable_if_t>()...>::value>>> { using argument_type = mpark::variant; 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; using value_type = mpark::lib::remove_const_t; return hash{}(alt.value); } #else hasher {} #endif , v); return hash_combine(result, hash{}(v.index())); } private: #ifndef MPARK_GENERIC_LAMBDAS struct hasher { template inline std::size_t operator()(const Alt& alt) const { using alt_type = mpark::lib::decay_t; using value_type = mpark::lib::remove_const_t; return hash{}(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 { 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 namespace std { using mpark::variant; using mpark::visit; using mpark::holds_alternative; using mpark::get; using mpark::get_if; using mpark::monostate; using mpark::bad_variant_access; using mpark::variant_size; using mpark::variant_alternative; using mpark::variant_alternative_t; } // namespace std #endif