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1617 lines
59 KiB
1617 lines
59 KiB
// -*- C++ -*-
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//===------------------------------ variant -------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP_VARIANT
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#define _LIBCPP_VARIANT
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/*
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variant synopsis
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namespace std {
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// 20.7.2, class template variant
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template <class... Types>
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class variant {
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public:
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// 20.7.2.1, constructors
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constexpr variant() noexcept(see below);
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variant(const variant&); // constexpr in C++20
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variant(variant&&) noexcept(see below); // constexpr in C++20
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template <class T> constexpr variant(T&&) noexcept(see below);
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template <class T, class... Args>
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constexpr explicit variant(in_place_type_t<T>, Args&&...);
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template <class T, class U, class... Args>
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constexpr explicit variant(
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in_place_type_t<T>, initializer_list<U>, Args&&...);
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template <size_t I, class... Args>
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constexpr explicit variant(in_place_index_t<I>, Args&&...);
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template <size_t I, class U, class... Args>
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constexpr explicit variant(
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in_place_index_t<I>, initializer_list<U>, Args&&...);
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// 20.7.2.2, destructor
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~variant();
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// 20.7.2.3, assignment
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variant& operator=(const variant&); // constexpr in C++20
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variant& operator=(variant&&) noexcept(see below); // constexpr in C++20
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template <class T> variant& operator=(T&&) noexcept(see below);
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// 20.7.2.4, modifiers
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template <class T, class... Args>
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T& emplace(Args&&...);
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template <class T, class U, class... Args>
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T& emplace(initializer_list<U>, Args&&...);
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template <size_t I, class... Args>
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variant_alternative_t<I, variant>& emplace(Args&&...);
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template <size_t I, class U, class... Args>
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variant_alternative_t<I, variant>& emplace(initializer_list<U>, Args&&...);
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// 20.7.2.5, value status
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constexpr bool valueless_by_exception() const noexcept;
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constexpr size_t index() const noexcept;
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// 20.7.2.6, swap
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void swap(variant&) noexcept(see below);
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};
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// 20.7.3, variant helper classes
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template <class T> struct variant_size; // undefined
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template <class T>
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inline constexpr size_t variant_size_v = variant_size<T>::value;
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template <class T> struct variant_size<const T>;
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template <class T> struct variant_size<volatile T>;
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template <class T> struct variant_size<const volatile T>;
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template <class... Types>
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struct variant_size<variant<Types...>>;
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template <size_t I, class T> struct variant_alternative; // undefined
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template <size_t I, class T>
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using variant_alternative_t = typename variant_alternative<I, T>::type;
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template <size_t I, class T> struct variant_alternative<I, const T>;
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template <size_t I, class T> struct variant_alternative<I, volatile T>;
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template <size_t I, class T> struct variant_alternative<I, const volatile T>;
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template <size_t I, class... Types>
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struct variant_alternative<I, variant<Types...>>;
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inline constexpr size_t variant_npos = -1;
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// 20.7.4, value access
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template <class T, class... Types>
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constexpr bool holds_alternative(const variant<Types...>&) noexcept;
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template <size_t I, class... Types>
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constexpr variant_alternative_t<I, variant<Types...>>&
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get(variant<Types...>&);
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template <size_t I, class... Types>
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constexpr variant_alternative_t<I, variant<Types...>>&&
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get(variant<Types...>&&);
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template <size_t I, class... Types>
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constexpr variant_alternative_t<I, variant<Types...>> const&
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get(const variant<Types...>&);
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template <size_t I, class... Types>
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constexpr variant_alternative_t<I, variant<Types...>> const&&
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get(const variant<Types...>&&);
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template <class T, class... Types>
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constexpr T& get(variant<Types...>&);
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template <class T, class... Types>
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constexpr T&& get(variant<Types...>&&);
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template <class T, class... Types>
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constexpr const T& get(const variant<Types...>&);
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template <class T, class... Types>
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constexpr const T&& get(const variant<Types...>&&);
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template <size_t I, class... Types>
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constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>
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get_if(variant<Types...>*) noexcept;
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template <size_t I, class... Types>
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constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>
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get_if(const variant<Types...>*) noexcept;
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template <class T, class... Types>
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constexpr add_pointer_t<T>
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get_if(variant<Types...>*) noexcept;
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template <class T, class... Types>
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constexpr add_pointer_t<const T>
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get_if(const variant<Types...>*) noexcept;
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// 20.7.5, relational operators
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template <class... Types>
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constexpr bool operator==(const variant<Types...>&, const variant<Types...>&);
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template <class... Types>
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constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&);
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template <class... Types>
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constexpr bool operator<(const variant<Types...>&, const variant<Types...>&);
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template <class... Types>
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constexpr bool operator>(const variant<Types...>&, const variant<Types...>&);
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template <class... Types>
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constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&);
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template <class... Types>
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constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&);
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// 20.7.6, visitation
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template <class Visitor, class... Variants>
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constexpr see below visit(Visitor&&, Variants&&...);
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// 20.7.7, class monostate
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struct monostate;
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// 20.7.8, monostate relational operators
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constexpr bool operator<(monostate, monostate) noexcept;
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constexpr bool operator>(monostate, monostate) noexcept;
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constexpr bool operator<=(monostate, monostate) noexcept;
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constexpr bool operator>=(monostate, monostate) noexcept;
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constexpr bool operator==(monostate, monostate) noexcept;
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constexpr bool operator!=(monostate, monostate) noexcept;
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// 20.7.9, specialized algorithms
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template <class... Types>
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void swap(variant<Types...>&, variant<Types...>&) noexcept(see below);
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// 20.7.10, class bad_variant_access
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class bad_variant_access;
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// 20.7.11, hash support
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template <class T> struct hash;
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template <class... Types> struct hash<variant<Types...>>;
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template <> struct hash<monostate>;
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} // namespace std
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*/
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#include <__config>
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#include <__tuple>
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#include <array>
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#include <exception>
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#include <functional>
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#include <initializer_list>
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#include <new>
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#include <tuple>
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#include <type_traits>
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#include <utility>
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#include <limits>
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#include <version>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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namespace std { // explicitly not using versioning namespace
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class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS bad_variant_access : public exception {
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public:
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virtual const char* what() const _NOEXCEPT;
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};
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} // namespace std
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if _LIBCPP_STD_VER > 14
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_LIBCPP_NORETURN
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inline _LIBCPP_INLINE_VISIBILITY
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_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
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void __throw_bad_variant_access() {
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#ifndef _LIBCPP_NO_EXCEPTIONS
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throw bad_variant_access();
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#else
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_VSTD::abort();
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#endif
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}
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template <class... _Types>
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class _LIBCPP_TEMPLATE_VIS variant;
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template <class _Tp>
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struct _LIBCPP_TEMPLATE_VIS variant_size;
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template <class _Tp>
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_LIBCPP_INLINE_VAR constexpr size_t variant_size_v = variant_size<_Tp>::value;
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template <class _Tp>
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struct _LIBCPP_TEMPLATE_VIS variant_size<const _Tp> : variant_size<_Tp> {};
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template <class _Tp>
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struct _LIBCPP_TEMPLATE_VIS variant_size<volatile _Tp> : variant_size<_Tp> {};
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template <class _Tp>
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struct _LIBCPP_TEMPLATE_VIS variant_size<const volatile _Tp>
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: variant_size<_Tp> {};
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template <class... _Types>
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struct _LIBCPP_TEMPLATE_VIS variant_size<variant<_Types...>>
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: integral_constant<size_t, sizeof...(_Types)> {};
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template <size_t _Ip, class _Tp>
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struct _LIBCPP_TEMPLATE_VIS variant_alternative;
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template <size_t _Ip, class _Tp>
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using variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type;
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template <size_t _Ip, class _Tp>
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struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const _Tp>
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: add_const<variant_alternative_t<_Ip, _Tp>> {};
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template <size_t _Ip, class _Tp>
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struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, volatile _Tp>
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: add_volatile<variant_alternative_t<_Ip, _Tp>> {};
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template <size_t _Ip, class _Tp>
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struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp>
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: add_cv<variant_alternative_t<_Ip, _Tp>> {};
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template <size_t _Ip, class... _Types>
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struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> {
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static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>");
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using type = __type_pack_element<_Ip, _Types...>;
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};
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_LIBCPP_INLINE_VAR constexpr size_t variant_npos = static_cast<size_t>(-1);
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constexpr int __choose_index_type(unsigned int __num_elem) {
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if (__num_elem < std::numeric_limits<unsigned char>::max())
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return 0;
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if (__num_elem < std::numeric_limits<unsigned short>::max())
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return 1;
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return 2;
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}
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template <size_t _NumAlts>
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using __variant_index_t =
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#ifndef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
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unsigned int;
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#else
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std::tuple_element_t<
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__choose_index_type(_NumAlts),
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std::tuple<unsigned char, unsigned short, unsigned int>
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>;
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#endif
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template <class _IndexType>
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constexpr _IndexType __variant_npos = static_cast<_IndexType>(-1);
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namespace __find_detail {
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template <class _Tp, class... _Types>
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inline _LIBCPP_INLINE_VISIBILITY
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constexpr size_t __find_index() {
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constexpr bool __matches[] = {is_same_v<_Tp, _Types>...};
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size_t __result = __not_found;
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for (size_t __i = 0; __i < sizeof...(_Types); ++__i) {
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if (__matches[__i]) {
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if (__result != __not_found) {
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return __ambiguous;
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}
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__result = __i;
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}
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}
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return __result;
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}
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template <size_t _Index>
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struct __find_unambiguous_index_sfinae_impl
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: integral_constant<size_t, _Index> {};
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template <>
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struct __find_unambiguous_index_sfinae_impl<__not_found> {};
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template <>
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struct __find_unambiguous_index_sfinae_impl<__ambiguous> {};
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template <class _Tp, class... _Types>
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struct __find_unambiguous_index_sfinae
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: __find_unambiguous_index_sfinae_impl<__find_index<_Tp, _Types...>()> {};
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} // namespace __find_detail
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namespace __variant_detail {
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struct __valueless_t {};
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enum class _Trait { _TriviallyAvailable, _Available, _Unavailable };
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template <typename _Tp,
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template <typename> class _IsTriviallyAvailable,
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template <typename> class _IsAvailable>
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constexpr _Trait __trait =
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_IsTriviallyAvailable<_Tp>::value
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? _Trait::_TriviallyAvailable
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: _IsAvailable<_Tp>::value ? _Trait::_Available : _Trait::_Unavailable;
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inline _LIBCPP_INLINE_VISIBILITY
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constexpr _Trait __common_trait(initializer_list<_Trait> __traits) {
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_Trait __result = _Trait::_TriviallyAvailable;
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for (_Trait __t : __traits) {
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if (static_cast<int>(__t) > static_cast<int>(__result)) {
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__result = __t;
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}
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}
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return __result;
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}
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template <typename... _Types>
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struct __traits {
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static constexpr _Trait __copy_constructible_trait =
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__common_trait({__trait<_Types,
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is_trivially_copy_constructible,
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is_copy_constructible>...});
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static constexpr _Trait __move_constructible_trait =
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__common_trait({__trait<_Types,
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is_trivially_move_constructible,
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is_move_constructible>...});
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static constexpr _Trait __copy_assignable_trait = __common_trait(
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{__copy_constructible_trait,
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__trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...});
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static constexpr _Trait __move_assignable_trait = __common_trait(
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{__move_constructible_trait,
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__trait<_Types, is_trivially_move_assignable, is_move_assignable>...});
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static constexpr _Trait __destructible_trait = __common_trait(
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{__trait<_Types, is_trivially_destructible, is_destructible>...});
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};
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namespace __access {
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struct __union {
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template <class _Vp>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) {
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return _VSTD::forward<_Vp>(__v).__head;
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}
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template <class _Vp, size_t _Ip>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) {
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return __get_alt(_VSTD::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>);
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}
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};
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struct __base {
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template <size_t _Ip, class _Vp>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr auto&& __get_alt(_Vp&& __v) {
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return __union::__get_alt(_VSTD::forward<_Vp>(__v).__data,
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in_place_index<_Ip>);
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}
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};
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struct __variant {
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template <size_t _Ip, class _Vp>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr auto&& __get_alt(_Vp&& __v) {
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return __base::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v).__impl);
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}
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};
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} // namespace __access
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namespace __visitation {
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struct __base {
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template <class _Visitor, class... _Vs>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr decltype(auto)
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__visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
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constexpr auto __fdiagonal =
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__make_fdiagonal<_Visitor&&,
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decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
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return __fdiagonal[__index](_VSTD::forward<_Visitor>(__visitor),
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_VSTD::forward<_Vs>(__vs).__as_base()...);
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}
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template <class _Visitor, class... _Vs>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor,
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_Vs&&... __vs) {
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constexpr auto __fmatrix =
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__make_fmatrix<_Visitor&&,
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decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
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return __at(__fmatrix, __vs.index()...)(
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_VSTD::forward<_Visitor>(__visitor),
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_VSTD::forward<_Vs>(__vs).__as_base()...);
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}
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private:
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr const _Tp& __at(const _Tp& __elem) { return __elem; }
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template <class _Tp, size_t _Np, typename... _Indices>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr auto&& __at(const array<_Tp, _Np>& __elems,
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size_t __index, _Indices... __indices) {
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return __at(__elems[__index], __indices...);
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}
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template <class _Fp, class... _Fs>
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static constexpr void __std_visit_visitor_return_type_check() {
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static_assert(
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__all<is_same_v<_Fp, _Fs>...>::value,
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"`std::visit` requires the visitor to have a single return type.");
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}
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template <class... _Fs>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr auto __make_farray(_Fs&&... __fs) {
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__std_visit_visitor_return_type_check<__uncvref_t<_Fs>...>();
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using __result = array<common_type_t<__uncvref_t<_Fs>...>, sizeof...(_Fs)>;
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return __result{{_VSTD::forward<_Fs>(__fs)...}};
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}
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template <std::size_t... _Is>
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struct __dispatcher {
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template <class _Fp, class... _Vs>
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inline _LIBCPP_INLINE_VISIBILITY
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static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) {
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return __invoke_constexpr(
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static_cast<_Fp>(__f),
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__access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...);
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}
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|
};
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|
|
template <class _Fp, class... _Vs, size_t... _Is>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr auto __make_dispatch(index_sequence<_Is...>) {
|
|
return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;
|
|
}
|
|
|
|
template <size_t _Ip, class _Fp, class... _Vs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr auto __make_fdiagonal_impl() {
|
|
return __make_dispatch<_Fp, _Vs...>(
|
|
index_sequence<(__identity<_Vs>{}, _Ip)...>{});
|
|
}
|
|
|
|
template <class _Fp, class... _Vs, size_t... _Is>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) {
|
|
return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...);
|
|
}
|
|
|
|
template <class _Fp, class _Vp, class... _Vs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr auto __make_fdiagonal() {
|
|
constexpr size_t _Np = __uncvref_t<_Vp>::__size();
|
|
static_assert(__all<(_Np == __uncvref_t<_Vs>::__size())...>::value);
|
|
return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<_Np>{});
|
|
}
|
|
|
|
template <class _Fp, class... _Vs, size_t... _Is>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) {
|
|
return __make_dispatch<_Fp, _Vs...>(__is);
|
|
}
|
|
|
|
template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr auto __make_fmatrix_impl(index_sequence<_Is...>,
|
|
index_sequence<_Js...>,
|
|
_Ls... __ls) {
|
|
return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>(
|
|
index_sequence<_Is..., _Js>{}, __ls...)...);
|
|
}
|
|
|
|
template <class _Fp, class... _Vs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr auto __make_fmatrix() {
|
|
return __make_fmatrix_impl<_Fp, _Vs...>(
|
|
index_sequence<>{}, make_index_sequence<__uncvref_t<_Vs>::__size()>{}...);
|
|
}
|
|
};
|
|
|
|
struct __variant {
|
|
template <class _Visitor, class... _Vs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr decltype(auto)
|
|
__visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
|
|
return __base::__visit_alt_at(__index,
|
|
_VSTD::forward<_Visitor>(__visitor),
|
|
_VSTD::forward<_Vs>(__vs).__impl...);
|
|
}
|
|
|
|
template <class _Visitor, class... _Vs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor,
|
|
_Vs&&... __vs) {
|
|
return __base::__visit_alt(_VSTD::forward<_Visitor>(__visitor),
|
|
_VSTD::forward<_Vs>(__vs).__impl...);
|
|
}
|
|
|
|
template <class _Visitor, class... _Vs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr decltype(auto)
|
|
__visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
|
|
return __visit_alt_at(
|
|
__index,
|
|
__make_value_visitor(_VSTD::forward<_Visitor>(__visitor)),
|
|
_VSTD::forward<_Vs>(__vs)...);
|
|
}
|
|
|
|
template <class _Visitor, class... _Vs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr decltype(auto) __visit_value(_Visitor&& __visitor,
|
|
_Vs&&... __vs) {
|
|
return __visit_alt(
|
|
__make_value_visitor(_VSTD::forward<_Visitor>(__visitor)),
|
|
_VSTD::forward<_Vs>(__vs)...);
|
|
}
|
|
|
|
private:
|
|
template <class _Visitor, class... _Values>
|
|
static constexpr void __std_visit_exhaustive_visitor_check() {
|
|
static_assert(is_invocable_v<_Visitor, _Values...>,
|
|
"`std::visit` requires the visitor to be exhaustive.");
|
|
}
|
|
|
|
template <class _Visitor>
|
|
struct __value_visitor {
|
|
template <class... _Alts>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr decltype(auto) operator()(_Alts&&... __alts) const {
|
|
__std_visit_exhaustive_visitor_check<
|
|
_Visitor,
|
|
decltype((_VSTD::forward<_Alts>(__alts).__value))...>();
|
|
return __invoke_constexpr(_VSTD::forward<_Visitor>(__visitor),
|
|
_VSTD::forward<_Alts>(__alts).__value...);
|
|
}
|
|
_Visitor&& __visitor;
|
|
};
|
|
|
|
template <class _Visitor>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
|
|
return __value_visitor<_Visitor>{_VSTD::forward<_Visitor>(__visitor)};
|
|
}
|
|
};
|
|
|
|
} // namespace __visitation
|
|
|
|
template <size_t _Index, class _Tp>
|
|
struct _LIBCPP_TEMPLATE_VIS __alt {
|
|
using __value_type = _Tp;
|
|
|
|
template <class... _Args>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
explicit constexpr __alt(in_place_t, _Args&&... __args)
|
|
: __value(_VSTD::forward<_Args>(__args)...) {}
|
|
|
|
__value_type __value;
|
|
};
|
|
|
|
template <_Trait _DestructibleTrait, size_t _Index, class... _Types>
|
|
union _LIBCPP_TEMPLATE_VIS __union;
|
|
|
|
template <_Trait _DestructibleTrait, size_t _Index>
|
|
union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {};
|
|
|
|
#define _LIBCPP_VARIANT_UNION(destructible_trait, destructor) \
|
|
template <size_t _Index, class _Tp, class... _Types> \
|
|
union _LIBCPP_TEMPLATE_VIS __union<destructible_trait, \
|
|
_Index, \
|
|
_Tp, \
|
|
_Types...> { \
|
|
public: \
|
|
inline _LIBCPP_INLINE_VISIBILITY \
|
|
explicit constexpr __union(__valueless_t) noexcept : __dummy{} {} \
|
|
\
|
|
template <class... _Args> \
|
|
inline _LIBCPP_INLINE_VISIBILITY \
|
|
explicit constexpr __union(in_place_index_t<0>, _Args&&... __args) \
|
|
: __head(in_place, _VSTD::forward<_Args>(__args)...) {} \
|
|
\
|
|
template <size_t _Ip, class... _Args> \
|
|
inline _LIBCPP_INLINE_VISIBILITY \
|
|
explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args) \
|
|
: __tail(in_place_index<_Ip - 1>, _VSTD::forward<_Args>(__args)...) {} \
|
|
\
|
|
__union(const __union&) = default; \
|
|
__union(__union&&) = default; \
|
|
\
|
|
destructor \
|
|
\
|
|
__union& operator=(const __union&) = default; \
|
|
__union& operator=(__union&&) = default; \
|
|
\
|
|
private: \
|
|
char __dummy; \
|
|
__alt<_Index, _Tp> __head; \
|
|
__union<destructible_trait, _Index + 1, _Types...> __tail; \
|
|
\
|
|
friend struct __access::__union; \
|
|
}
|
|
|
|
_LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable, ~__union() = default;);
|
|
_LIBCPP_VARIANT_UNION(_Trait::_Available, ~__union() {});
|
|
_LIBCPP_VARIANT_UNION(_Trait::_Unavailable, ~__union() = delete;);
|
|
|
|
#undef _LIBCPP_VARIANT_UNION
|
|
|
|
template <_Trait _DestructibleTrait, class... _Types>
|
|
class _LIBCPP_TEMPLATE_VIS __base {
|
|
public:
|
|
using __index_t = __variant_index_t<sizeof...(_Types)>;
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
explicit constexpr __base(__valueless_t tag) noexcept
|
|
: __data(tag), __index(__variant_npos<__index_t>) {}
|
|
|
|
template <size_t _Ip, class... _Args>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args)
|
|
:
|
|
__data(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...),
|
|
__index(_Ip) {}
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool valueless_by_exception() const noexcept {
|
|
return index() == variant_npos;
|
|
}
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr size_t index() const noexcept {
|
|
return __index == __variant_npos<__index_t> ? variant_npos : __index;
|
|
}
|
|
|
|
protected:
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr auto&& __as_base() & { return *this; }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr auto&& __as_base() && { return _VSTD::move(*this); }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr auto&& __as_base() const & { return *this; }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr auto&& __as_base() const && { return _VSTD::move(*this); }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static constexpr size_t __size() { return sizeof...(_Types); }
|
|
|
|
__union<_DestructibleTrait, 0, _Types...> __data;
|
|
__index_t __index;
|
|
|
|
friend struct __access::__base;
|
|
friend struct __visitation::__base;
|
|
};
|
|
|
|
template <class _Traits, _Trait = _Traits::__destructible_trait>
|
|
class _LIBCPP_TEMPLATE_VIS __destructor;
|
|
|
|
#define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor, destroy) \
|
|
template <class... _Types> \
|
|
class _LIBCPP_TEMPLATE_VIS __destructor<__traits<_Types...>, \
|
|
destructible_trait> \
|
|
: public __base<destructible_trait, _Types...> { \
|
|
using __base_type = __base<destructible_trait, _Types...>; \
|
|
using __index_t = typename __base_type::__index_t; \
|
|
\
|
|
public: \
|
|
using __base_type::__base_type; \
|
|
using __base_type::operator=; \
|
|
\
|
|
__destructor(const __destructor&) = default; \
|
|
__destructor(__destructor&&) = default; \
|
|
destructor \
|
|
__destructor& operator=(const __destructor&) = default; \
|
|
__destructor& operator=(__destructor&&) = default; \
|
|
\
|
|
protected: \
|
|
inline _LIBCPP_INLINE_VISIBILITY \
|
|
destroy \
|
|
}
|
|
|
|
_LIBCPP_VARIANT_DESTRUCTOR(
|
|
_Trait::_TriviallyAvailable,
|
|
~__destructor() = default;,
|
|
void __destroy() noexcept { this->__index = __variant_npos<__index_t>; });
|
|
|
|
_LIBCPP_VARIANT_DESTRUCTOR(
|
|
_Trait::_Available,
|
|
~__destructor() { __destroy(); },
|
|
void __destroy() noexcept {
|
|
if (!this->valueless_by_exception()) {
|
|
__visitation::__base::__visit_alt(
|
|
[](auto& __alt) noexcept {
|
|
using __alt_type = __uncvref_t<decltype(__alt)>;
|
|
__alt.~__alt_type();
|
|
},
|
|
*this);
|
|
}
|
|
this->__index = __variant_npos<__index_t>;
|
|
});
|
|
|
|
_LIBCPP_VARIANT_DESTRUCTOR(
|
|
_Trait::_Unavailable,
|
|
~__destructor() = delete;,
|
|
void __destroy() noexcept = delete;);
|
|
|
|
#undef _LIBCPP_VARIANT_DESTRUCTOR
|
|
|
|
template <class _Traits>
|
|
class _LIBCPP_TEMPLATE_VIS __constructor : public __destructor<_Traits> {
|
|
using __base_type = __destructor<_Traits>;
|
|
|
|
public:
|
|
using __base_type::__base_type;
|
|
using __base_type::operator=;
|
|
|
|
protected:
|
|
template <size_t _Ip, class _Tp, class... _Args>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static _Tp& __construct_alt(__alt<_Ip, _Tp>& __a, _Args&&... __args) {
|
|
::new ((void*)_VSTD::addressof(__a))
|
|
__alt<_Ip, _Tp>(in_place, _VSTD::forward<_Args>(__args)...);
|
|
return __a.__value;
|
|
}
|
|
|
|
template <class _Rhs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
static void __generic_construct(__constructor& __lhs, _Rhs&& __rhs) {
|
|
__lhs.__destroy();
|
|
if (!__rhs.valueless_by_exception()) {
|
|
__visitation::__base::__visit_alt_at(
|
|
__rhs.index(),
|
|
[](auto& __lhs_alt, auto&& __rhs_alt) {
|
|
__construct_alt(
|
|
__lhs_alt,
|
|
_VSTD::forward<decltype(__rhs_alt)>(__rhs_alt).__value);
|
|
},
|
|
__lhs, _VSTD::forward<_Rhs>(__rhs));
|
|
__lhs.__index = __rhs.index();
|
|
}
|
|
}
|
|
};
|
|
|
|
template <class _Traits, _Trait = _Traits::__move_constructible_trait>
|
|
class _LIBCPP_TEMPLATE_VIS __move_constructor;
|
|
|
|
#define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, \
|
|
move_constructor) \
|
|
template <class... _Types> \
|
|
class _LIBCPP_TEMPLATE_VIS __move_constructor<__traits<_Types...>, \
|
|
move_constructible_trait> \
|
|
: public __constructor<__traits<_Types...>> { \
|
|
using __base_type = __constructor<__traits<_Types...>>; \
|
|
\
|
|
public: \
|
|
using __base_type::__base_type; \
|
|
using __base_type::operator=; \
|
|
\
|
|
__move_constructor(const __move_constructor&) = default; \
|
|
move_constructor \
|
|
~__move_constructor() = default; \
|
|
__move_constructor& operator=(const __move_constructor&) = default; \
|
|
__move_constructor& operator=(__move_constructor&&) = default; \
|
|
}
|
|
|
|
_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
|
|
_Trait::_TriviallyAvailable,
|
|
__move_constructor(__move_constructor&& __that) = default;);
|
|
|
|
_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
|
|
_Trait::_Available,
|
|
__move_constructor(__move_constructor&& __that) noexcept(
|
|
__all<is_nothrow_move_constructible_v<_Types>...>::value)
|
|
: __move_constructor(__valueless_t{}) {
|
|
this->__generic_construct(*this, _VSTD::move(__that));
|
|
});
|
|
|
|
_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
|
|
_Trait::_Unavailable,
|
|
__move_constructor(__move_constructor&&) = delete;);
|
|
|
|
#undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR
|
|
|
|
template <class _Traits, _Trait = _Traits::__copy_constructible_trait>
|
|
class _LIBCPP_TEMPLATE_VIS __copy_constructor;
|
|
|
|
#define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, \
|
|
copy_constructor) \
|
|
template <class... _Types> \
|
|
class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>, \
|
|
copy_constructible_trait> \
|
|
: public __move_constructor<__traits<_Types...>> { \
|
|
using __base_type = __move_constructor<__traits<_Types...>>; \
|
|
\
|
|
public: \
|
|
using __base_type::__base_type; \
|
|
using __base_type::operator=; \
|
|
\
|
|
copy_constructor \
|
|
__copy_constructor(__copy_constructor&&) = default; \
|
|
~__copy_constructor() = default; \
|
|
__copy_constructor& operator=(const __copy_constructor&) = default; \
|
|
__copy_constructor& operator=(__copy_constructor&&) = default; \
|
|
}
|
|
|
|
_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
|
|
_Trait::_TriviallyAvailable,
|
|
__copy_constructor(const __copy_constructor& __that) = default;);
|
|
|
|
_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
|
|
_Trait::_Available,
|
|
__copy_constructor(const __copy_constructor& __that)
|
|
: __copy_constructor(__valueless_t{}) {
|
|
this->__generic_construct(*this, __that);
|
|
});
|
|
|
|
_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
|
|
_Trait::_Unavailable,
|
|
__copy_constructor(const __copy_constructor&) = delete;);
|
|
|
|
#undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR
|
|
|
|
template <class _Traits>
|
|
class _LIBCPP_TEMPLATE_VIS __assignment : public __copy_constructor<_Traits> {
|
|
using __base_type = __copy_constructor<_Traits>;
|
|
|
|
public:
|
|
using __base_type::__base_type;
|
|
using __base_type::operator=;
|
|
|
|
template <size_t _Ip, class... _Args>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
auto& __emplace(_Args&&... __args) {
|
|
this->__destroy();
|
|
auto& __res = this->__construct_alt(__access::__base::__get_alt<_Ip>(*this),
|
|
_VSTD::forward<_Args>(__args)...);
|
|
this->__index = _Ip;
|
|
return __res;
|
|
}
|
|
|
|
protected:
|
|
template <size_t _Ip, class _Tp, class _Arg>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) {
|
|
if (this->index() == _Ip) {
|
|
__a.__value = _VSTD::forward<_Arg>(__arg);
|
|
} else {
|
|
struct {
|
|
void operator()(true_type) const {
|
|
__this->__emplace<_Ip>(_VSTD::forward<_Arg>(__arg));
|
|
}
|
|
void operator()(false_type) const {
|
|
__this->__emplace<_Ip>(_Tp(_VSTD::forward<_Arg>(__arg)));
|
|
}
|
|
__assignment* __this;
|
|
_Arg&& __arg;
|
|
} __impl{this, _VSTD::forward<_Arg>(__arg)};
|
|
__impl(bool_constant<is_nothrow_constructible_v<_Tp, _Arg> ||
|
|
!is_nothrow_move_constructible_v<_Tp>>{});
|
|
}
|
|
}
|
|
|
|
template <class _That>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
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(),
|
|
[this](auto& __this_alt, auto&& __that_alt) {
|
|
this->__assign_alt(
|
|
__this_alt,
|
|
_VSTD::forward<decltype(__that_alt)>(__that_alt).__value);
|
|
},
|
|
*this, _VSTD::forward<_That>(__that));
|
|
}
|
|
}
|
|
};
|
|
|
|
template <class _Traits, _Trait = _Traits::__move_assignable_trait>
|
|
class _LIBCPP_TEMPLATE_VIS __move_assignment;
|
|
|
|
#define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, \
|
|
move_assignment) \
|
|
template <class... _Types> \
|
|
class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>, \
|
|
move_assignable_trait> \
|
|
: public __assignment<__traits<_Types...>> { \
|
|
using __base_type = __assignment<__traits<_Types...>>; \
|
|
\
|
|
public: \
|
|
using __base_type::__base_type; \
|
|
using __base_type::operator=; \
|
|
\
|
|
__move_assignment(const __move_assignment&) = default; \
|
|
__move_assignment(__move_assignment&&) = default; \
|
|
~__move_assignment() = default; \
|
|
__move_assignment& operator=(const __move_assignment&) = default; \
|
|
move_assignment \
|
|
}
|
|
|
|
_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
|
|
_Trait::_TriviallyAvailable,
|
|
__move_assignment& operator=(__move_assignment&& __that) = default;);
|
|
|
|
_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
|
|
_Trait::_Available,
|
|
__move_assignment& operator=(__move_assignment&& __that) noexcept(
|
|
__all<(is_nothrow_move_constructible_v<_Types> &&
|
|
is_nothrow_move_assignable_v<_Types>)...>::value) {
|
|
this->__generic_assign(_VSTD::move(__that));
|
|
return *this;
|
|
});
|
|
|
|
_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
|
|
_Trait::_Unavailable,
|
|
__move_assignment& operator=(__move_assignment&&) = delete;);
|
|
|
|
#undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT
|
|
|
|
template <class _Traits, _Trait = _Traits::__copy_assignable_trait>
|
|
class _LIBCPP_TEMPLATE_VIS __copy_assignment;
|
|
|
|
#define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait, \
|
|
copy_assignment) \
|
|
template <class... _Types> \
|
|
class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>, \
|
|
copy_assignable_trait> \
|
|
: public __move_assignment<__traits<_Types...>> { \
|
|
using __base_type = __move_assignment<__traits<_Types...>>; \
|
|
\
|
|
public: \
|
|
using __base_type::__base_type; \
|
|
using __base_type::operator=; \
|
|
\
|
|
__copy_assignment(const __copy_assignment&) = default; \
|
|
__copy_assignment(__copy_assignment&&) = default; \
|
|
~__copy_assignment() = default; \
|
|
copy_assignment \
|
|
__copy_assignment& operator=(__copy_assignment&&) = default; \
|
|
}
|
|
|
|
_LIBCPP_VARIANT_COPY_ASSIGNMENT(
|
|
_Trait::_TriviallyAvailable,
|
|
__copy_assignment& operator=(const __copy_assignment& __that) = default;);
|
|
|
|
_LIBCPP_VARIANT_COPY_ASSIGNMENT(
|
|
_Trait::_Available,
|
|
__copy_assignment& operator=(const __copy_assignment& __that) {
|
|
this->__generic_assign(__that);
|
|
return *this;
|
|
});
|
|
|
|
_LIBCPP_VARIANT_COPY_ASSIGNMENT(
|
|
_Trait::_Unavailable,
|
|
__copy_assignment& operator=(const __copy_assignment&) = delete;);
|
|
|
|
#undef _LIBCPP_VARIANT_COPY_ASSIGNMENT
|
|
|
|
template <class... _Types>
|
|
class _LIBCPP_TEMPLATE_VIS __impl
|
|
: public __copy_assignment<__traits<_Types...>> {
|
|
using __base_type = __copy_assignment<__traits<_Types...>>;
|
|
|
|
public:
|
|
using __base_type::__base_type;
|
|
using __base_type::operator=;
|
|
|
|
template <size_t _Ip, class _Arg>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
void __assign(_Arg&& __arg) {
|
|
this->__assign_alt(__access::__base::__get_alt<_Ip>(*this),
|
|
_VSTD::forward<_Arg>(__arg));
|
|
}
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
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(),
|
|
[](auto& __this_alt, auto& __that_alt) {
|
|
using _VSTD::swap;
|
|
swap(__this_alt.__value, __that_alt.__value);
|
|
},
|
|
*this,
|
|
__that);
|
|
} else {
|
|
__impl* __lhs = this;
|
|
__impl* __rhs = _VSTD::addressof(__that);
|
|
if (__lhs->__move_nothrow() && !__rhs->__move_nothrow()) {
|
|
_VSTD::swap(__lhs, __rhs);
|
|
}
|
|
__impl __tmp(_VSTD::move(*__rhs));
|
|
#ifndef _LIBCPP_NO_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, _VSTD::move(*__lhs));
|
|
} catch (...) {
|
|
if (__tmp.__move_nothrow()) {
|
|
this->__generic_construct(*__rhs, _VSTD::move(__tmp));
|
|
}
|
|
throw;
|
|
}
|
|
#else
|
|
this->__generic_construct(*__rhs, _VSTD::move(*__lhs));
|
|
#endif
|
|
this->__generic_construct(*__lhs, _VSTD::move(__tmp));
|
|
}
|
|
}
|
|
|
|
private:
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
bool __move_nothrow() const {
|
|
constexpr bool __results[] = {is_nothrow_move_constructible_v<_Types>...};
|
|
return this->valueless_by_exception() || __results[this->index()];
|
|
}
|
|
};
|
|
|
|
template <class... _Types>
|
|
struct __overload;
|
|
|
|
template <>
|
|
struct __overload<> { void operator()() const; };
|
|
|
|
template <class _Tp, class... _Types>
|
|
struct __overload<_Tp, _Types...> : __overload<_Types...> {
|
|
using __overload<_Types...>::operator();
|
|
__identity<_Tp> operator()(_Tp) const;
|
|
};
|
|
|
|
template <class _Tp, class... _Types>
|
|
using __best_match_t = typename result_of_t<__overload<_Types...>(_Tp&&)>::type;
|
|
|
|
} // __variant_detail
|
|
|
|
template <class... _Types>
|
|
class _LIBCPP_TEMPLATE_VIS variant
|
|
: private __sfinae_ctor_base<
|
|
__all<is_copy_constructible_v<_Types>...>::value,
|
|
__all<is_move_constructible_v<_Types>...>::value>,
|
|
private __sfinae_assign_base<
|
|
__all<(is_copy_constructible_v<_Types> &&
|
|
is_copy_assignable_v<_Types>)...>::value,
|
|
__all<(is_move_constructible_v<_Types> &&
|
|
is_move_assignable_v<_Types>)...>::value> {
|
|
static_assert(0 < sizeof...(_Types),
|
|
"variant must consist of at least one alternative.");
|
|
|
|
static_assert(__all<!is_array_v<_Types>...>::value,
|
|
"variant can not have an array type as an alternative.");
|
|
|
|
static_assert(__all<!is_reference_v<_Types>...>::value,
|
|
"variant can not have a reference type as an alternative.");
|
|
|
|
static_assert(__all<!is_void_v<_Types>...>::value,
|
|
"variant can not have a void type as an alternative.");
|
|
|
|
using __first_type = variant_alternative_t<0, variant>;
|
|
|
|
public:
|
|
template <bool _Dummy = true,
|
|
enable_if_t<__dependent_type<is_default_constructible<__first_type>,
|
|
_Dummy>::value,
|
|
int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>)
|
|
: __impl(in_place_index<0>) {}
|
|
|
|
variant(const variant&) = default;
|
|
variant(variant&&) = default;
|
|
|
|
template <
|
|
class _Arg,
|
|
enable_if_t<!is_same_v<__uncvref_t<_Arg>, variant>, int> = 0,
|
|
enable_if_t<!__is_inplace_type<__uncvref_t<_Arg>>::value, int> = 0,
|
|
enable_if_t<!__is_inplace_index<__uncvref_t<_Arg>>::value, int> = 0,
|
|
class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,
|
|
size_t _Ip =
|
|
__find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
|
|
enable_if_t<is_constructible_v<_Tp, _Arg>, int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr variant(_Arg&& __arg) noexcept(
|
|
is_nothrow_constructible_v<_Tp, _Arg>)
|
|
: __impl(in_place_index<_Ip>, _VSTD::forward<_Arg>(__arg)) {}
|
|
|
|
template <size_t _Ip, class... _Args,
|
|
class = enable_if_t<(_Ip < sizeof...(_Types)), int>,
|
|
class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
|
|
enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
explicit constexpr variant(
|
|
in_place_index_t<_Ip>,
|
|
_Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
|
|
: __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
|
|
|
|
template <
|
|
size_t _Ip,
|
|
class _Up,
|
|
class... _Args,
|
|
enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
|
|
class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
|
|
enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
|
|
int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
explicit constexpr variant(
|
|
in_place_index_t<_Ip>,
|
|
initializer_list<_Up> __il,
|
|
_Args&&... __args) noexcept(
|
|
is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>)
|
|
: __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
|
|
|
|
template <
|
|
class _Tp,
|
|
class... _Args,
|
|
size_t _Ip =
|
|
__find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
|
|
enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept(
|
|
is_nothrow_constructible_v<_Tp, _Args...>)
|
|
: __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
|
|
|
|
template <
|
|
class _Tp,
|
|
class _Up,
|
|
class... _Args,
|
|
size_t _Ip =
|
|
__find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
|
|
enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
|
|
int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
explicit constexpr variant(
|
|
in_place_type_t<_Tp>,
|
|
initializer_list<_Up> __il,
|
|
_Args&&... __args) noexcept(
|
|
is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>)
|
|
: __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
|
|
|
|
~variant() = default;
|
|
|
|
variant& operator=(const variant&) = default;
|
|
variant& operator=(variant&&) = default;
|
|
|
|
template <
|
|
class _Arg,
|
|
enable_if_t<!is_same_v<__uncvref_t<_Arg>, variant>, int> = 0,
|
|
class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,
|
|
size_t _Ip =
|
|
__find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
|
|
enable_if_t<is_assignable_v<_Tp&, _Arg> && is_constructible_v<_Tp, _Arg>,
|
|
int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
variant& operator=(_Arg&& __arg) noexcept(
|
|
is_nothrow_assignable_v<_Tp&, _Arg> &&
|
|
is_nothrow_constructible_v<_Tp, _Arg>) {
|
|
__impl.template __assign<_Ip>(_VSTD::forward<_Arg>(__arg));
|
|
return *this;
|
|
}
|
|
|
|
template <
|
|
size_t _Ip,
|
|
class... _Args,
|
|
enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
|
|
class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
|
|
enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_Tp& emplace(_Args&&... __args) {
|
|
return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
|
|
}
|
|
|
|
template <
|
|
size_t _Ip,
|
|
class _Up,
|
|
class... _Args,
|
|
enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
|
|
class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
|
|
enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
|
|
int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
|
|
return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
|
|
}
|
|
|
|
template <
|
|
class _Tp,
|
|
class... _Args,
|
|
size_t _Ip =
|
|
__find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
|
|
enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_Tp& emplace(_Args&&... __args) {
|
|
return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
|
|
}
|
|
|
|
template <
|
|
class _Tp,
|
|
class _Up,
|
|
class... _Args,
|
|
size_t _Ip =
|
|
__find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
|
|
enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
|
|
int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
|
|
return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
|
|
}
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool valueless_by_exception() const noexcept {
|
|
return __impl.valueless_by_exception();
|
|
}
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr size_t index() const noexcept { return __impl.index(); }
|
|
|
|
template <
|
|
bool _Dummy = true,
|
|
enable_if_t<
|
|
__all<(
|
|
__dependent_type<is_move_constructible<_Types>, _Dummy>::value &&
|
|
__dependent_type<is_swappable<_Types>, _Dummy>::value)...>::value,
|
|
int> = 0>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
void swap(variant& __that) noexcept(
|
|
__all<(is_nothrow_move_constructible_v<_Types> &&
|
|
is_nothrow_swappable_v<_Types>)...>::value) {
|
|
__impl.__swap(__that.__impl);
|
|
}
|
|
|
|
private:
|
|
__variant_detail::__impl<_Types...> __impl;
|
|
|
|
friend struct __variant_detail::__access::__variant;
|
|
friend struct __variant_detail::__visitation::__variant;
|
|
};
|
|
|
|
template <size_t _Ip, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool __holds_alternative(const variant<_Types...>& __v) noexcept {
|
|
return __v.index() == _Ip;
|
|
}
|
|
|
|
template <class _Tp, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool holds_alternative(const variant<_Types...>& __v) noexcept {
|
|
return __holds_alternative<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
|
|
}
|
|
|
|
template <size_t _Ip, class _Vp>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr auto&& __generic_get(_Vp&& __v) {
|
|
using __variant_detail::__access::__variant;
|
|
if (!__holds_alternative<_Ip>(__v)) {
|
|
__throw_bad_variant_access();
|
|
}
|
|
return __variant::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v)).__value;
|
|
}
|
|
|
|
template <size_t _Ip, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr variant_alternative_t<_Ip, variant<_Types...>>& get(
|
|
variant<_Types...>& __v) {
|
|
static_assert(_Ip < sizeof...(_Types));
|
|
static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
|
|
return __generic_get<_Ip>(__v);
|
|
}
|
|
|
|
template <size_t _Ip, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr variant_alternative_t<_Ip, variant<_Types...>>&& get(
|
|
variant<_Types...>&& __v) {
|
|
static_assert(_Ip < sizeof...(_Types));
|
|
static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
|
|
return __generic_get<_Ip>(_VSTD::move(__v));
|
|
}
|
|
|
|
template <size_t _Ip, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr const variant_alternative_t<_Ip, variant<_Types...>>& get(
|
|
const variant<_Types...>& __v) {
|
|
static_assert(_Ip < sizeof...(_Types));
|
|
static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
|
|
return __generic_get<_Ip>(__v);
|
|
}
|
|
|
|
template <size_t _Ip, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr const variant_alternative_t<_Ip, variant<_Types...>>&& get(
|
|
const variant<_Types...>&& __v) {
|
|
static_assert(_Ip < sizeof...(_Types));
|
|
static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
|
|
return __generic_get<_Ip>(_VSTD::move(__v));
|
|
}
|
|
|
|
template <class _Tp, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr _Tp& get(variant<_Types...>& __v) {
|
|
static_assert(!is_void_v<_Tp>);
|
|
return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
|
|
}
|
|
|
|
template <class _Tp, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr _Tp&& get(variant<_Types...>&& __v) {
|
|
static_assert(!is_void_v<_Tp>);
|
|
return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(
|
|
_VSTD::move(__v));
|
|
}
|
|
|
|
template <class _Tp, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr const _Tp& get(const variant<_Types...>& __v) {
|
|
static_assert(!is_void_v<_Tp>);
|
|
return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
|
|
}
|
|
|
|
template <class _Tp, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr const _Tp&& get(const variant<_Types...>&& __v) {
|
|
static_assert(!is_void_v<_Tp>);
|
|
return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(
|
|
_VSTD::move(__v));
|
|
}
|
|
|
|
template <size_t _Ip, class _Vp>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr auto* __generic_get_if(_Vp* __v) noexcept {
|
|
using __variant_detail::__access::__variant;
|
|
return __v && __holds_alternative<_Ip>(*__v)
|
|
? _VSTD::addressof(__variant::__get_alt<_Ip>(*__v).__value)
|
|
: nullptr;
|
|
}
|
|
|
|
template <size_t _Ip, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr add_pointer_t<variant_alternative_t<_Ip, variant<_Types...>>>
|
|
get_if(variant<_Types...>* __v) noexcept {
|
|
static_assert(_Ip < sizeof...(_Types));
|
|
static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
|
|
return __generic_get_if<_Ip>(__v);
|
|
}
|
|
|
|
template <size_t _Ip, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr add_pointer_t<const variant_alternative_t<_Ip, variant<_Types...>>>
|
|
get_if(const variant<_Types...>* __v) noexcept {
|
|
static_assert(_Ip < sizeof...(_Types));
|
|
static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
|
|
return __generic_get_if<_Ip>(__v);
|
|
}
|
|
|
|
template <class _Tp, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr add_pointer_t<_Tp>
|
|
get_if(variant<_Types...>* __v) noexcept {
|
|
static_assert(!is_void_v<_Tp>);
|
|
return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
|
|
}
|
|
|
|
template <class _Tp, class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr add_pointer_t<const _Tp>
|
|
get_if(const variant<_Types...>* __v) noexcept {
|
|
static_assert(!is_void_v<_Tp>);
|
|
return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
|
|
}
|
|
|
|
template <class _Operator>
|
|
struct __convert_to_bool {
|
|
template <class _T1, class _T2>
|
|
_LIBCPP_INLINE_VISIBILITY constexpr bool operator()(_T1 && __t1, _T2&& __t2) const {
|
|
static_assert(std::is_convertible<decltype(_Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2))), bool>::value,
|
|
"the relational operator does not return a type which is implicitly convertible to bool");
|
|
return _Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
|
|
}
|
|
};
|
|
|
|
template <class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator==(const variant<_Types...>& __lhs,
|
|
const variant<_Types...>& __rhs) {
|
|
using __variant_detail::__visitation::__variant;
|
|
if (__lhs.index() != __rhs.index()) return false;
|
|
if (__lhs.valueless_by_exception()) return true;
|
|
return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<equal_to<>>{}, __lhs, __rhs);
|
|
}
|
|
|
|
template <class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator!=(const variant<_Types...>& __lhs,
|
|
const variant<_Types...>& __rhs) {
|
|
using __variant_detail::__visitation::__variant;
|
|
if (__lhs.index() != __rhs.index()) return true;
|
|
if (__lhs.valueless_by_exception()) return false;
|
|
return __variant::__visit_value_at(
|
|
__lhs.index(), __convert_to_bool<not_equal_to<>>{}, __lhs, __rhs);
|
|
}
|
|
|
|
template <class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator<(const variant<_Types...>& __lhs,
|
|
const variant<_Types...>& __rhs) {
|
|
using __variant_detail::__visitation::__variant;
|
|
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(), __convert_to_bool<less<>>{}, __lhs, __rhs);
|
|
}
|
|
|
|
template <class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator>(const variant<_Types...>& __lhs,
|
|
const variant<_Types...>& __rhs) {
|
|
using __variant_detail::__visitation::__variant;
|
|
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(), __convert_to_bool<greater<>>{}, __lhs, __rhs);
|
|
}
|
|
|
|
template <class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator<=(const variant<_Types...>& __lhs,
|
|
const variant<_Types...>& __rhs) {
|
|
using __variant_detail::__visitation::__variant;
|
|
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(), __convert_to_bool<less_equal<>>{}, __lhs, __rhs);
|
|
}
|
|
|
|
template <class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator>=(const variant<_Types...>& __lhs,
|
|
const variant<_Types...>& __rhs) {
|
|
using __variant_detail::__visitation::__variant;
|
|
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(), __convert_to_bool<greater_equal<>>{}, __lhs, __rhs);
|
|
}
|
|
|
|
template <class _Visitor, class... _Vs>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
|
|
constexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) {
|
|
using __variant_detail::__visitation::__variant;
|
|
bool __results[] = {__vs.valueless_by_exception()...};
|
|
for (bool __result : __results) {
|
|
if (__result) {
|
|
__throw_bad_variant_access();
|
|
}
|
|
}
|
|
return __variant::__visit_value(_VSTD::forward<_Visitor>(__visitor),
|
|
_VSTD::forward<_Vs>(__vs)...);
|
|
}
|
|
|
|
struct _LIBCPP_TEMPLATE_VIS monostate {};
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator<(monostate, monostate) noexcept { return false; }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator>(monostate, monostate) noexcept { return false; }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator<=(monostate, monostate) noexcept { return true; }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator>=(monostate, monostate) noexcept { return true; }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator==(monostate, monostate) noexcept { return true; }
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
constexpr bool operator!=(monostate, monostate) noexcept { return false; }
|
|
|
|
template <class... _Types>
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
auto swap(variant<_Types...>& __lhs,
|
|
variant<_Types...>& __rhs) noexcept(noexcept(__lhs.swap(__rhs)))
|
|
-> decltype(__lhs.swap(__rhs)) {
|
|
__lhs.swap(__rhs);
|
|
}
|
|
|
|
template <class... _Types>
|
|
struct _LIBCPP_TEMPLATE_VIS hash<
|
|
__enable_hash_helper<variant<_Types...>, remove_const_t<_Types>...>> {
|
|
using argument_type = variant<_Types...>;
|
|
using result_type = size_t;
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
result_type operator()(const argument_type& __v) const {
|
|
using __variant_detail::__visitation::__variant;
|
|
size_t __res =
|
|
__v.valueless_by_exception()
|
|
? 299792458 // Random value chosen by the universe upon creation
|
|
: __variant::__visit_alt(
|
|
[](const auto& __alt) {
|
|
using __alt_type = __uncvref_t<decltype(__alt)>;
|
|
using __value_type = remove_const_t<
|
|
typename __alt_type::__value_type>;
|
|
return hash<__value_type>{}(__alt.__value);
|
|
},
|
|
__v);
|
|
return __hash_combine(__res, hash<size_t>{}(__v.index()));
|
|
}
|
|
};
|
|
|
|
template <>
|
|
struct _LIBCPP_TEMPLATE_VIS hash<monostate> {
|
|
using argument_type = monostate;
|
|
using result_type = size_t;
|
|
|
|
inline _LIBCPP_INLINE_VISIBILITY
|
|
result_type operator()(const argument_type&) const _NOEXCEPT {
|
|
return 66740831; // return a fundamentally attractive random value.
|
|
}
|
|
};
|
|
|
|
#endif // _LIBCPP_STD_VER > 14
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
_LIBCPP_POP_MACROS
|
|
|
|
#endif // _LIBCPP_VARIANT
|