f78958c9b4
* include/bits/c++config (_GLIBCXX17_DEPRECATED): Define. * include/bits/functional_hash.h (__hash_base::result_type) (__hash_base::argument_type): Add _GLIBCXX17_DEPRECATED. * include/std/optional (hash<optional<T>>::result_type) (hash<optional<T>>::argument_type): Add deprecated attribute. (__is_fast_hash<hash<optional<T>>>): Add partial specialization. * include/std/variant (hash<variant<Types...>>::result_type) (hash<variant<Types...>>::argument_type): Add deprecated attribute. (__is_fast_hash<hash<variant<Types...>>>): Add partial specialization. From-SVN: r253017
1452 lines
47 KiB
C++
1452 lines
47 KiB
C++
// <variant> -*- C++ -*-
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// Copyright (C) 2016-2017 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file variant
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* This is the <variant> C++ Library header.
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*/
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#ifndef _GLIBCXX_VARIANT
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#define _GLIBCXX_VARIANT 1
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#pragma GCC system_header
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#if __cplusplus >= 201703L
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#include <type_traits>
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#include <utility>
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#include <bits/enable_special_members.h>
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#include <bits/functexcept.h>
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#include <bits/move.h>
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#include <bits/functional_hash.h>
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#include <bits/invoke.h>
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#include <ext/aligned_buffer.h>
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#include <bits/parse_numbers.h>
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#include <bits/stl_iterator_base_types.h>
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#include <bits/stl_iterator_base_funcs.h>
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#include <bits/stl_construct.h>
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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namespace __detail
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{
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namespace __variant
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{
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template<size_t _Np, typename... _Types>
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struct _Nth_type;
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template<size_t _Np, typename _First, typename... _Rest>
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struct _Nth_type<_Np, _First, _Rest...>
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: _Nth_type<_Np-1, _Rest...> { };
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template<typename _First, typename... _Rest>
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struct _Nth_type<0, _First, _Rest...>
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{ using type = _First; };
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} // namespace __variant
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} // namespace __detail
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#define __cpp_lib_variant 201603
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template<typename... _Types> class tuple;
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template<typename... _Types> class variant;
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template <typename> struct hash;
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template<typename _Variant>
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struct variant_size;
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template<typename _Variant>
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struct variant_size<const _Variant> : variant_size<_Variant> {};
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template<typename _Variant>
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struct variant_size<volatile _Variant> : variant_size<_Variant> {};
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template<typename _Variant>
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struct variant_size<const volatile _Variant> : variant_size<_Variant> {};
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template<typename... _Types>
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struct variant_size<variant<_Types...>>
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: std::integral_constant<size_t, sizeof...(_Types)> {};
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template<typename _Variant>
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inline constexpr size_t variant_size_v = variant_size<_Variant>::value;
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template<size_t _Np, typename _Variant>
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struct variant_alternative;
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template<size_t _Np, typename _First, typename... _Rest>
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struct variant_alternative<_Np, variant<_First, _Rest...>>
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: variant_alternative<_Np-1, variant<_Rest...>> {};
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template<typename _First, typename... _Rest>
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struct variant_alternative<0, variant<_First, _Rest...>>
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{ using type = _First; };
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template<size_t _Np, typename _Variant>
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using variant_alternative_t =
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typename variant_alternative<_Np, _Variant>::type;
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template<size_t _Np, typename _Variant>
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struct variant_alternative<_Np, const _Variant>
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{ using type = add_const_t<variant_alternative_t<_Np, _Variant>>; };
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template<size_t _Np, typename _Variant>
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struct variant_alternative<_Np, volatile _Variant>
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{ using type = add_volatile_t<variant_alternative_t<_Np, _Variant>>; };
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template<size_t _Np, typename _Variant>
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struct variant_alternative<_Np, const volatile _Variant>
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{ using type = add_cv_t<variant_alternative_t<_Np, _Variant>>; };
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inline constexpr size_t variant_npos = -1;
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template<size_t _Np, typename... _Types>
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constexpr variant_alternative_t<_Np, variant<_Types...>>&
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get(variant<_Types...>&);
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template<size_t _Np, typename... _Types>
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constexpr variant_alternative_t<_Np, variant<_Types...>>&&
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get(variant<_Types...>&&);
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template<size_t _Np, typename... _Types>
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constexpr variant_alternative_t<_Np, variant<_Types...>> const&
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get(const variant<_Types...>&);
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template<size_t _Np, typename... _Types>
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constexpr variant_alternative_t<_Np, variant<_Types...>> const&&
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get(const variant<_Types...>&&);
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namespace __detail
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{
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namespace __variant
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{
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// Returns the first apparence of _Tp in _Types.
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// Returns sizeof...(_Types) if _Tp is not in _Types.
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template<typename _Tp, typename... _Types>
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struct __index_of : std::integral_constant<size_t, 0> {};
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template<typename _Tp, typename... _Types>
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inline constexpr size_t __index_of_v = __index_of<_Tp, _Types...>::value;
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template<typename _Tp, typename _First, typename... _Rest>
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struct __index_of<_Tp, _First, _Rest...> :
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std::integral_constant<size_t, is_same_v<_Tp, _First>
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? 0 : __index_of_v<_Tp, _Rest...> + 1> {};
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// _Uninitialized<T> is guaranteed to be a literal type, even if T is not.
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// We have to do this, because [basic.types]p10.5.3 (n4606) is not implemented
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// yet. When it's implemented, _Uninitialized<T> can be changed to the alias
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// to T, therefore equivalent to being removed entirely.
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//
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// Another reason we may not want to remove _Uninitialzied<T> may be that, we
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// want _Uninitialized<T> to be trivially destructible, no matter whether T
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// is; but we will see.
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template<typename _Type, bool = std::is_literal_type_v<_Type>>
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struct _Uninitialized;
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template<typename _Type>
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struct _Uninitialized<_Type, true>
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{
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template<typename... _Args>
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constexpr _Uninitialized(in_place_index_t<0>, _Args&&... __args)
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: _M_storage(std::forward<_Args>(__args)...)
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{ }
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constexpr const _Type& _M_get() const &
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{ return _M_storage; }
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constexpr _Type& _M_get() &
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{ return _M_storage; }
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constexpr const _Type&& _M_get() const &&
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{ return std::move(_M_storage); }
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constexpr _Type&& _M_get() &&
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{ return std::move(_M_storage); }
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_Type _M_storage;
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};
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template<typename _Type>
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struct _Uninitialized<_Type, false>
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{
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template<typename... _Args>
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constexpr _Uninitialized(in_place_index_t<0>, _Args&&... __args)
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{ ::new (&_M_storage) _Type(std::forward<_Args>(__args)...); }
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const _Type& _M_get() const &
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{ return *_M_storage._M_ptr(); }
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_Type& _M_get() &
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{ return *_M_storage._M_ptr(); }
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const _Type&& _M_get() const &&
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{ return std::move(*_M_storage._M_ptr()); }
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_Type&& _M_get() &&
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{ return std::move(*_M_storage._M_ptr()); }
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__gnu_cxx::__aligned_membuf<_Type> _M_storage;
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};
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template<typename _Ref>
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_Ref __ref_cast(void* __ptr)
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{
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return static_cast<_Ref>(*static_cast<remove_reference_t<_Ref>*>(__ptr));
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}
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template<typename _Union>
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constexpr decltype(auto) __get(in_place_index_t<0>, _Union&& __u)
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{ return std::forward<_Union>(__u)._M_first._M_get(); }
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template<size_t _Np, typename _Union>
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constexpr decltype(auto) __get(in_place_index_t<_Np>, _Union&& __u)
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{ return __get(in_place_index<_Np-1>, std::forward<_Union>(__u)._M_rest); }
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// Returns the typed storage for __v.
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template<size_t _Np, typename _Variant>
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constexpr decltype(auto) __get(_Variant&& __v)
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{
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return __get(std::in_place_index<_Np>, std::forward<_Variant>(__v)._M_u);
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}
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// Various functions as "vtable" entries, where those vtables are used by
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// polymorphic operations.
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template<typename _Lhs, typename _Rhs>
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void
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__erased_ctor(void* __lhs, void* __rhs)
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{
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using _Type = remove_reference_t<_Lhs>;
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::new (__lhs) _Type(__variant::__ref_cast<_Rhs>(__rhs));
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}
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template<typename _Variant, size_t _Np>
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void
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__erased_dtor(_Variant&& __v)
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{ std::_Destroy(std::__addressof(__get<_Np>(__v))); }
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template<typename _Lhs, typename _Rhs>
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void
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__erased_assign(void* __lhs, void* __rhs)
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{
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__variant::__ref_cast<_Lhs>(__lhs) = __variant::__ref_cast<_Rhs>(__rhs);
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}
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template<typename _Lhs, typename _Rhs>
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void
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__erased_swap(void* __lhs, void* __rhs)
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{
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using std::swap;
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swap(__variant::__ref_cast<_Lhs>(__lhs),
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__variant::__ref_cast<_Rhs>(__rhs));
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}
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#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP, __NAME) \
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template<typename _Variant, size_t _Np> \
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constexpr bool \
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__erased_##__NAME(const _Variant& __lhs, const _Variant& __rhs) \
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{ \
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return __get<_Np>(std::forward<_Variant>(__lhs)) \
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__OP __get<_Np>(std::forward<_Variant>(__rhs)); \
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}
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_VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
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_VARIANT_RELATION_FUNCTION_TEMPLATE(<=, less_equal)
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_VARIANT_RELATION_FUNCTION_TEMPLATE(==, equal)
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_VARIANT_RELATION_FUNCTION_TEMPLATE(!=, not_equal)
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_VARIANT_RELATION_FUNCTION_TEMPLATE(>=, greater_equal)
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_VARIANT_RELATION_FUNCTION_TEMPLATE(>, greater)
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#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
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template<typename _Tp>
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size_t
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__erased_hash(void* __t)
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{
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return std::hash<remove_cv_t<remove_reference_t<_Tp>>>{}(
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__variant::__ref_cast<_Tp>(__t));
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}
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template<typename... _Types>
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struct _Traits
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{
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static constexpr bool _S_default_ctor =
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is_default_constructible_v<typename _Nth_type<0, _Types...>::type>;
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static constexpr bool _S_copy_ctor =
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(is_copy_constructible_v<_Types> && ...);
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static constexpr bool _S_move_ctor =
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(is_move_constructible_v<_Types> && ...);
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static constexpr bool _S_copy_assign =
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_S_copy_ctor && _S_move_ctor
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&& (is_copy_assignable_v<_Types> && ...);
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static constexpr bool _S_move_assign =
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_S_move_ctor
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&& (is_move_assignable_v<_Types> && ...);
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static constexpr bool _S_trivial_dtor =
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(is_trivially_destructible_v<_Types> && ...);
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static constexpr bool _S_trivial_copy_ctor =
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(is_trivially_copy_constructible_v<_Types> && ...);
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static constexpr bool _S_trivial_move_ctor =
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(is_trivially_move_constructible_v<_Types> && ...);
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static constexpr bool _S_trivial_copy_assign =
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_S_trivial_dtor && (is_trivially_copy_assignable_v<_Types> && ...);
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static constexpr bool _S_trivial_move_assign =
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_S_trivial_dtor && (is_trivially_move_assignable_v<_Types> && ...);
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// The following nothrow traits are for non-trivial SMFs. Trivial SMFs
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// are always nothrow.
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static constexpr bool _S_nothrow_default_ctor =
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is_nothrow_default_constructible_v<
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typename _Nth_type<0, _Types...>::type>;
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static constexpr bool _S_nothrow_copy_ctor = false;
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static constexpr bool _S_nothrow_move_ctor =
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(is_nothrow_move_constructible_v<_Types> && ...);
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static constexpr bool _S_nothrow_copy_assign = false;
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static constexpr bool _S_nothrow_move_assign =
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_S_nothrow_move_ctor && (is_nothrow_move_assignable_v<_Types> && ...);
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};
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// Defines members and ctors.
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template<typename... _Types>
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union _Variadic_union { };
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template<typename _First, typename... _Rest>
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union _Variadic_union<_First, _Rest...>
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{
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constexpr _Variadic_union() : _M_rest() { }
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template<typename... _Args>
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constexpr _Variadic_union(in_place_index_t<0>, _Args&&... __args)
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: _M_first(in_place_index<0>, std::forward<_Args>(__args)...)
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{ }
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template<size_t _Np, typename... _Args>
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constexpr _Variadic_union(in_place_index_t<_Np>, _Args&&... __args)
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: _M_rest(in_place_index<_Np-1>, std::forward<_Args>(__args)...)
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{ }
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_Uninitialized<_First> _M_first;
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_Variadic_union<_Rest...> _M_rest;
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};
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// Defines index and the dtor, possibly trivial.
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template<bool __trivially_destructible, typename... _Types>
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struct _Variant_storage;
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template <typename... _Types>
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using __select_index =
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typename __select_int::_Select_int_base<sizeof...(_Types)+1,
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unsigned char,
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unsigned short>
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::type::value_type;
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template<typename... _Types>
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struct _Variant_storage<false, _Types...>
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{
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template<size_t... __indices>
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static constexpr void (*_S_vtable[])(const _Variant_storage&) =
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{ &__erased_dtor<const _Variant_storage&, __indices>... };
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constexpr _Variant_storage() : _M_index(variant_npos) { }
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template<size_t _Np, typename... _Args>
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constexpr _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
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: _M_u(in_place_index<_Np>, std::forward<_Args>(__args)...),
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_M_index(_Np)
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{ }
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template<size_t... __indices>
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constexpr void _M_reset_impl(std::index_sequence<__indices...>)
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{
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if (_M_index != __index_type(variant_npos))
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_S_vtable<__indices...>[_M_index](*this);
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}
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void _M_reset()
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{
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_M_reset_impl(std::index_sequence_for<_Types...>{});
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_M_index = variant_npos;
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}
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~_Variant_storage()
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{ _M_reset(); }
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void*
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_M_storage() const
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{
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return const_cast<void*>(static_cast<const void*>(
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std::addressof(_M_u)));
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}
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constexpr bool
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_M_valid() const noexcept
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{
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return this->_M_index != __index_type(variant_npos);
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}
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_Variadic_union<_Types...> _M_u;
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using __index_type = __select_index<_Types...>;
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__index_type _M_index;
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};
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template<typename... _Types>
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struct _Variant_storage<true, _Types...>
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{
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constexpr _Variant_storage() : _M_index(variant_npos) { }
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template<size_t _Np, typename... _Args>
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constexpr _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
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: _M_u(in_place_index<_Np>, std::forward<_Args>(__args)...),
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_M_index(_Np)
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{ }
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void _M_reset()
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{ _M_index = variant_npos; }
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void*
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_M_storage() const
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{
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return const_cast<void*>(static_cast<const void*>(
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std::addressof(_M_u)));
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}
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|
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constexpr bool
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|
_M_valid() const noexcept
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|
{
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return this->_M_index != __index_type(variant_npos);
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}
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_Variadic_union<_Types...> _M_u;
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using __index_type = __select_index<_Types...>;
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__index_type _M_index;
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};
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template<typename... _Types>
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using _Variant_storage_alias =
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_Variant_storage<_Traits<_Types...>::_S_trivial_dtor, _Types...>;
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// The following are (Copy|Move) (ctor|assign) layers for forwarding
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// triviality and handling non-trivial SMF behaviors.
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template<bool, typename... _Types>
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struct _Copy_ctor_base : _Variant_storage_alias<_Types...>
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{
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using _Base = _Variant_storage_alias<_Types...>;
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using _Base::_Base;
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_Copy_ctor_base(const _Copy_ctor_base& __rhs)
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noexcept(_Traits<_Types...>::_S_nothrow_copy_ctor)
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{
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if (__rhs._M_valid())
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{
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static constexpr void (*_S_vtable[])(void*, void*) =
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{ &__erased_ctor<_Types&, const _Types&>... };
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_S_vtable[__rhs._M_index](this->_M_storage(), __rhs._M_storage());
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this->_M_index = __rhs._M_index;
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}
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}
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_Copy_ctor_base(_Copy_ctor_base&&) = default;
|
|
_Copy_ctor_base& operator=(const _Copy_ctor_base&) = default;
|
|
_Copy_ctor_base& operator=(_Copy_ctor_base&&) = default;
|
|
};
|
|
|
|
template<typename... _Types>
|
|
struct _Copy_ctor_base<true, _Types...> : _Variant_storage_alias<_Types...>
|
|
{
|
|
using _Base = _Variant_storage_alias<_Types...>;
|
|
using _Base::_Base;
|
|
};
|
|
|
|
template<typename... _Types>
|
|
using _Copy_ctor_alias =
|
|
_Copy_ctor_base<_Traits<_Types...>::_S_trivial_copy_ctor, _Types...>;
|
|
|
|
template<bool, typename... _Types>
|
|
struct _Move_ctor_base : _Copy_ctor_alias<_Types...>
|
|
{
|
|
using _Base = _Copy_ctor_alias<_Types...>;
|
|
using _Base::_Base;
|
|
|
|
_Move_ctor_base(_Move_ctor_base&& __rhs)
|
|
noexcept(_Traits<_Types...>::_S_nothrow_move_ctor)
|
|
{
|
|
if (__rhs._M_valid())
|
|
{
|
|
static constexpr void (*_S_vtable[])(void*, void*) =
|
|
{ &__erased_ctor<_Types&, _Types&&>... };
|
|
_S_vtable[__rhs._M_index](this->_M_storage(), __rhs._M_storage());
|
|
this->_M_index = __rhs._M_index;
|
|
}
|
|
}
|
|
|
|
_Move_ctor_base(const _Move_ctor_base&) = default;
|
|
_Move_ctor_base& operator=(const _Move_ctor_base&) = default;
|
|
_Move_ctor_base& operator=(_Move_ctor_base&&) = default;
|
|
};
|
|
|
|
template<typename... _Types>
|
|
struct _Move_ctor_base<true, _Types...> : _Copy_ctor_alias<_Types...>
|
|
{
|
|
using _Base = _Copy_ctor_alias<_Types...>;
|
|
using _Base::_Base;
|
|
};
|
|
|
|
template<typename... _Types>
|
|
using _Move_ctor_alias =
|
|
_Move_ctor_base<_Traits<_Types...>::_S_trivial_move_ctor, _Types...>;
|
|
|
|
template<bool, typename... _Types>
|
|
struct _Copy_assign_base : _Move_ctor_alias<_Types...>
|
|
{
|
|
using _Base = _Move_ctor_alias<_Types...>;
|
|
using _Base::_Base;
|
|
|
|
_Copy_assign_base&
|
|
operator=(const _Copy_assign_base& __rhs)
|
|
noexcept(_Traits<_Types...>::_S_nothrow_copy_assign)
|
|
{
|
|
if (this->_M_index == __rhs._M_index)
|
|
{
|
|
if (__rhs._M_valid())
|
|
{
|
|
static constexpr void (*_S_vtable[])(void*, void*) =
|
|
{ &__erased_assign<_Types&, const _Types&>... };
|
|
_S_vtable[__rhs._M_index](this->_M_storage(), __rhs._M_storage());
|
|
}
|
|
}
|
|
else
|
|
{
|
|
_Copy_assign_base __tmp(__rhs);
|
|
this->~_Copy_assign_base();
|
|
__try
|
|
{
|
|
::new (this) _Copy_assign_base(std::move(__tmp));
|
|
}
|
|
__catch (...)
|
|
{
|
|
this->_M_index = variant_npos;
|
|
__throw_exception_again;
|
|
}
|
|
}
|
|
__glibcxx_assert(this->_M_index == __rhs._M_index);
|
|
return *this;
|
|
}
|
|
|
|
_Copy_assign_base(const _Copy_assign_base&) = default;
|
|
_Copy_assign_base(_Copy_assign_base&&) = default;
|
|
_Copy_assign_base& operator=(_Copy_assign_base&&) = default;
|
|
};
|
|
|
|
template<typename... _Types>
|
|
struct _Copy_assign_base<true, _Types...> : _Move_ctor_alias<_Types...>
|
|
{
|
|
using _Base = _Move_ctor_alias<_Types...>;
|
|
using _Base::_Base;
|
|
};
|
|
|
|
template<typename... _Types>
|
|
using _Copy_assign_alias =
|
|
_Copy_assign_base<_Traits<_Types...>::_S_trivial_copy_assign,
|
|
_Types...>;
|
|
|
|
template<bool, typename... _Types>
|
|
struct _Move_assign_base : _Copy_assign_alias<_Types...>
|
|
{
|
|
using _Base = _Copy_assign_alias<_Types...>;
|
|
using _Base::_Base;
|
|
|
|
void _M_destructive_move(_Move_assign_base&& __rhs)
|
|
{
|
|
this->~_Move_assign_base();
|
|
__try
|
|
{
|
|
::new (this) _Move_assign_base(std::move(__rhs));
|
|
}
|
|
__catch (...)
|
|
{
|
|
this->_M_index = variant_npos;
|
|
__throw_exception_again;
|
|
}
|
|
}
|
|
|
|
_Move_assign_base&
|
|
operator=(_Move_assign_base&& __rhs)
|
|
noexcept(_Traits<_Types...>::_S_nothrow_move_assign)
|
|
{
|
|
if (this->_M_index == __rhs._M_index)
|
|
{
|
|
if (__rhs._M_valid())
|
|
{
|
|
static constexpr void (*_S_vtable[])(void*, void*) =
|
|
{ &__erased_assign<_Types&, const _Types&>... };
|
|
_S_vtable[__rhs._M_index](this->_M_storage(), __rhs._M_storage());
|
|
}
|
|
}
|
|
else
|
|
{
|
|
_Move_assign_base __tmp(__rhs);
|
|
this->~_Move_assign_base();
|
|
__try
|
|
{
|
|
::new (this) _Move_assign_base(std::move(__tmp));
|
|
}
|
|
__catch (...)
|
|
{
|
|
this->_M_index = variant_npos;
|
|
__throw_exception_again;
|
|
}
|
|
}
|
|
__glibcxx_assert(this->_M_index == __rhs._M_index);
|
|
return *this;
|
|
}
|
|
|
|
_Move_assign_base(const _Move_assign_base&) = default;
|
|
_Move_assign_base(_Move_assign_base&&) = default;
|
|
_Move_assign_base& operator=(const _Move_assign_base&) = default;
|
|
};
|
|
|
|
template<typename... _Types>
|
|
struct _Move_assign_base<true, _Types...> : _Copy_assign_alias<_Types...>
|
|
{
|
|
using _Base = _Copy_assign_alias<_Types...>;
|
|
using _Base::_Base;
|
|
};
|
|
|
|
template<typename... _Types>
|
|
using _Move_assign_alias =
|
|
_Move_assign_base<_Traits<_Types...>::_S_trivial_move_assign,
|
|
_Types...>;
|
|
|
|
template<typename... _Types>
|
|
struct _Variant_base : _Move_assign_alias<_Types...>
|
|
{
|
|
using _Base = _Move_assign_alias<_Types...>;
|
|
|
|
constexpr
|
|
_Variant_base()
|
|
noexcept(_Traits<_Types...>::_S_nothrow_default_ctor)
|
|
: _Variant_base(in_place_index<0>) { }
|
|
|
|
template<size_t _Np, typename... _Args>
|
|
constexpr explicit
|
|
_Variant_base(in_place_index_t<_Np> __i, _Args&&... __args)
|
|
: _Base(__i, std::forward<_Args>(__args)...)
|
|
{ }
|
|
|
|
_Variant_base(const _Variant_base&) = default;
|
|
_Variant_base(_Variant_base&&) = default;
|
|
_Variant_base& operator=(const _Variant_base&) = default;
|
|
_Variant_base& operator=(_Variant_base&&) = default;
|
|
};
|
|
|
|
// For how many times does _Tp appear in _Tuple?
|
|
template<typename _Tp, typename _Tuple>
|
|
struct __tuple_count;
|
|
|
|
template<typename _Tp, typename _Tuple>
|
|
inline constexpr size_t __tuple_count_v =
|
|
__tuple_count<_Tp, _Tuple>::value;
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
struct __tuple_count<_Tp, tuple<_Types...>>
|
|
: integral_constant<size_t, 0> { };
|
|
|
|
template<typename _Tp, typename _First, typename... _Rest>
|
|
struct __tuple_count<_Tp, tuple<_First, _Rest...>>
|
|
: integral_constant<
|
|
size_t,
|
|
__tuple_count_v<_Tp, tuple<_Rest...>> + is_same_v<_Tp, _First>> { };
|
|
|
|
// TODO: Reuse this in <tuple> ?
|
|
template<typename _Tp, typename... _Types>
|
|
inline constexpr bool __exactly_once =
|
|
__tuple_count_v<_Tp, tuple<_Types...>> == 1;
|
|
|
|
// Takes _Types and create an overloaded _S_fun for each type.
|
|
// If a type appears more than once in _Types, create only one overload.
|
|
template<typename... _Types>
|
|
struct __overload_set
|
|
{ static void _S_fun(); };
|
|
|
|
template<typename _First, typename... _Rest>
|
|
struct __overload_set<_First, _Rest...> : __overload_set<_Rest...>
|
|
{
|
|
using __overload_set<_Rest...>::_S_fun;
|
|
static integral_constant<size_t, sizeof...(_Rest)> _S_fun(_First);
|
|
};
|
|
|
|
template<typename... _Rest>
|
|
struct __overload_set<void, _Rest...> : __overload_set<_Rest...>
|
|
{
|
|
using __overload_set<_Rest...>::_S_fun;
|
|
};
|
|
|
|
// Helper for variant(_Tp&&) and variant::operator=(_Tp&&).
|
|
// __accepted_index maps the arbitrary _Tp to an alternative type in _Variant.
|
|
template<typename _Tp, typename _Variant, typename = void>
|
|
struct __accepted_index
|
|
{ static constexpr size_t value = variant_npos; };
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
struct __accepted_index<
|
|
_Tp, variant<_Types...>,
|
|
decltype(__overload_set<_Types...>::_S_fun(std::declval<_Tp>()),
|
|
std::declval<void>())>
|
|
{
|
|
static constexpr size_t value = sizeof...(_Types) - 1
|
|
- decltype(__overload_set<_Types...>::
|
|
_S_fun(std::declval<_Tp>()))::value;
|
|
};
|
|
|
|
// Returns the raw storage for __v.
|
|
template<typename _Variant>
|
|
void* __get_storage(_Variant&& __v)
|
|
{ return __v._M_storage(); }
|
|
|
|
// Used for storing multi-dimensional vtable.
|
|
template<typename _Tp, size_t... _Dimensions>
|
|
struct _Multi_array
|
|
{
|
|
constexpr const _Tp&
|
|
_M_access() const
|
|
{ return _M_data; }
|
|
|
|
_Tp _M_data;
|
|
};
|
|
|
|
template<typename _Tp, size_t __first, size_t... __rest>
|
|
struct _Multi_array<_Tp, __first, __rest...>
|
|
{
|
|
template<typename... _Args>
|
|
constexpr const _Tp&
|
|
_M_access(size_t __first_index, _Args... __rest_indices) const
|
|
{ return _M_arr[__first_index]._M_access(__rest_indices...); }
|
|
|
|
_Multi_array<_Tp, __rest...> _M_arr[__first];
|
|
};
|
|
|
|
// Creates a multi-dimensional vtable recursively.
|
|
//
|
|
// For example,
|
|
// visit([](auto, auto){},
|
|
// variant<int, char>(), // typedef'ed as V1
|
|
// variant<float, double, long double>()) // typedef'ed as V2
|
|
// will trigger instantiations of:
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&), 2, 3>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<>>
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&), 3>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<0>>
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&)>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<0, 0>>
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&)>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<0, 1>>
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&)>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<0, 2>>
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&), 3>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<1>>
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&)>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<1, 0>>
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&)>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<1, 1>>
|
|
// __gen_vtable_impl<_Multi_array<void(*)(V1&&, V2&&)>,
|
|
// tuple<V1&&, V2&&>, std::index_sequence<1, 2>>
|
|
// The returned multi-dimensional vtable can be fast accessed by the visitor
|
|
// using index calculation.
|
|
template<typename _Array_type, typename _Variant_tuple, typename _Index_seq>
|
|
struct __gen_vtable_impl;
|
|
|
|
template<typename _Result_type, typename _Visitor, size_t... __dimensions,
|
|
typename... _Variants, size_t... __indices>
|
|
struct __gen_vtable_impl<
|
|
_Multi_array<_Result_type (*)(_Visitor, _Variants...), __dimensions...>,
|
|
tuple<_Variants...>, std::index_sequence<__indices...>>
|
|
{
|
|
using _Next =
|
|
remove_reference_t<typename _Nth_type<sizeof...(__indices),
|
|
_Variants...>::type>;
|
|
using _Array_type =
|
|
_Multi_array<_Result_type (*)(_Visitor, _Variants...),
|
|
__dimensions...>;
|
|
|
|
static constexpr _Array_type
|
|
_S_apply()
|
|
{
|
|
_Array_type __vtable{};
|
|
_S_apply_all_alts(
|
|
__vtable, make_index_sequence<variant_size_v<_Next>>());
|
|
return __vtable;
|
|
}
|
|
|
|
template<size_t... __var_indices>
|
|
static constexpr void
|
|
_S_apply_all_alts(_Array_type& __vtable,
|
|
std::index_sequence<__var_indices...>)
|
|
{
|
|
(_S_apply_single_alt<__var_indices>(
|
|
__vtable._M_arr[__var_indices]), ...);
|
|
}
|
|
|
|
template<size_t __index, typename _Tp>
|
|
static constexpr void
|
|
_S_apply_single_alt(_Tp& __element)
|
|
{
|
|
using _Alternative = variant_alternative_t<__index, _Next>;
|
|
__element = __gen_vtable_impl<
|
|
remove_reference_t<
|
|
decltype(__element)>, tuple<_Variants...>,
|
|
std::index_sequence<__indices..., __index>>::_S_apply();
|
|
}
|
|
};
|
|
|
|
template<typename _Result_type, typename _Visitor, typename... _Variants,
|
|
size_t... __indices>
|
|
struct __gen_vtable_impl<
|
|
_Multi_array<_Result_type (*)(_Visitor, _Variants...)>,
|
|
tuple<_Variants...>, std::index_sequence<__indices...>>
|
|
{
|
|
using _Array_type =
|
|
_Multi_array<_Result_type (*)(_Visitor&&, _Variants...)>;
|
|
|
|
decltype(auto)
|
|
static constexpr __visit_invoke(_Visitor&& __visitor, _Variants... __vars)
|
|
{
|
|
return __invoke(std::forward<_Visitor>(__visitor),
|
|
std::get<__indices>(
|
|
std::forward<_Variants>(__vars))...);
|
|
}
|
|
|
|
static constexpr auto
|
|
_S_apply()
|
|
{ return _Array_type{&__visit_invoke}; }
|
|
};
|
|
|
|
template<typename _Result_type, typename _Visitor, typename... _Variants>
|
|
struct __gen_vtable
|
|
{
|
|
using _Func_ptr = _Result_type (*)(_Visitor&&, _Variants...);
|
|
using _Array_type =
|
|
_Multi_array<_Func_ptr,
|
|
variant_size_v<remove_reference_t<_Variants>>...>;
|
|
|
|
static constexpr _Array_type
|
|
_S_apply()
|
|
{
|
|
return __gen_vtable_impl<_Array_type, tuple<_Variants...>,
|
|
std::index_sequence<>>::_S_apply();
|
|
}
|
|
|
|
static constexpr auto _S_vtable = _S_apply();
|
|
};
|
|
|
|
template<size_t _Np, typename _Tp>
|
|
struct _Base_dedup : public _Tp { };
|
|
|
|
template<typename _Variant, typename __indices>
|
|
struct _Variant_hash_base;
|
|
|
|
template<typename... _Types, size_t... __indices>
|
|
struct _Variant_hash_base<variant<_Types...>,
|
|
std::index_sequence<__indices...>>
|
|
: _Base_dedup<__indices, __poison_hash<remove_const_t<_Types>>>... { };
|
|
|
|
} // namespace __variant
|
|
} // namespace __detail
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
inline constexpr bool holds_alternative(const variant<_Types...>& __v)
|
|
noexcept
|
|
{
|
|
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
|
|
"T should occur for exactly once in alternatives");
|
|
return __v.index() == __detail::__variant::__index_of_v<_Tp, _Types...>;
|
|
}
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
constexpr inline _Tp& get(variant<_Types...>& __v)
|
|
{
|
|
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
|
|
"T should occur for exactly once in alternatives");
|
|
static_assert(!is_void_v<_Tp>, "_Tp should not be void");
|
|
return get<__detail::__variant::__index_of_v<_Tp, _Types...>>(__v);
|
|
}
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
constexpr inline _Tp&& get(variant<_Types...>&& __v)
|
|
{
|
|
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
|
|
"T should occur for exactly once in alternatives");
|
|
static_assert(!is_void_v<_Tp>, "_Tp should not be void");
|
|
return get<__detail::__variant::__index_of_v<_Tp, _Types...>>(
|
|
std::move(__v));
|
|
}
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
constexpr inline const _Tp& get(const variant<_Types...>& __v)
|
|
{
|
|
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
|
|
"T should occur for exactly once in alternatives");
|
|
static_assert(!is_void_v<_Tp>, "_Tp should not be void");
|
|
return get<__detail::__variant::__index_of_v<_Tp, _Types...>>(__v);
|
|
}
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
constexpr inline const _Tp&& get(const variant<_Types...>&& __v)
|
|
{
|
|
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
|
|
"T should occur for exactly once in alternatives");
|
|
static_assert(!is_void_v<_Tp>, "_Tp should not be void");
|
|
return get<__detail::__variant::__index_of_v<_Tp, _Types...>>(
|
|
std::move(__v));
|
|
}
|
|
|
|
template<size_t _Np, typename... _Types>
|
|
constexpr inline
|
|
add_pointer_t<variant_alternative_t<_Np, variant<_Types...>>>
|
|
get_if(variant<_Types...>* __ptr) noexcept
|
|
{
|
|
using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
|
|
static_assert(_Np < sizeof...(_Types),
|
|
"The index should be in [0, number of alternatives)");
|
|
static_assert(!is_void_v<_Alternative_type>, "_Tp should not be void");
|
|
if (__ptr && __ptr->index() == _Np)
|
|
return &__detail::__variant::__get<_Np>(*__ptr);
|
|
return nullptr;
|
|
}
|
|
|
|
template<size_t _Np, typename... _Types>
|
|
constexpr inline
|
|
add_pointer_t<const variant_alternative_t<_Np, variant<_Types...>>>
|
|
get_if(const variant<_Types...>* __ptr) noexcept
|
|
{
|
|
using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
|
|
static_assert(_Np < sizeof...(_Types),
|
|
"The index should be in [0, number of alternatives)");
|
|
static_assert(!is_void_v<_Alternative_type>, "_Tp should not be void");
|
|
if (__ptr && __ptr->index() == _Np)
|
|
return &__detail::__variant::__get<_Np>(*__ptr);
|
|
return nullptr;
|
|
}
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
constexpr inline add_pointer_t<_Tp>
|
|
get_if(variant<_Types...>* __ptr) noexcept
|
|
{
|
|
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
|
|
"T should occur for exactly once in alternatives");
|
|
static_assert(!is_void_v<_Tp>, "_Tp should not be void");
|
|
return get_if<__detail::__variant::__index_of_v<_Tp, _Types...>>(__ptr);
|
|
}
|
|
|
|
template<typename _Tp, typename... _Types>
|
|
constexpr inline add_pointer_t<const _Tp>
|
|
get_if(const variant<_Types...>* __ptr)
|
|
noexcept
|
|
{
|
|
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
|
|
"T should occur for exactly once in alternatives");
|
|
static_assert(!is_void_v<_Tp>, "_Tp should not be void");
|
|
return get_if<__detail::__variant::__index_of_v<_Tp, _Types...>>(__ptr);
|
|
}
|
|
|
|
struct monostate { };
|
|
|
|
#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP, __NAME) \
|
|
template<typename... _Types> \
|
|
constexpr bool operator __OP(const variant<_Types...>& __lhs, \
|
|
const variant<_Types...>& __rhs) \
|
|
{ \
|
|
return __lhs._M_##__NAME(__rhs, std::index_sequence_for<_Types...>{}); \
|
|
} \
|
|
\
|
|
constexpr bool operator __OP(monostate, monostate) noexcept \
|
|
{ return 0 __OP 0; }
|
|
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(<=, less_equal)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(==, equal)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(!=, not_equal)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(>=, greater_equal)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(>, greater)
|
|
|
|
#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
|
|
|
|
template<typename _Visitor, typename... _Variants>
|
|
constexpr decltype(auto) visit(_Visitor&&, _Variants&&...);
|
|
|
|
template<typename... _Types>
|
|
inline enable_if_t<(is_move_constructible_v<_Types> && ...)
|
|
&& (is_swappable_v<_Types> && ...)>
|
|
swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs)
|
|
noexcept(noexcept(__lhs.swap(__rhs)))
|
|
{ __lhs.swap(__rhs); }
|
|
|
|
template<typename... _Types>
|
|
enable_if_t<!((is_move_constructible_v<_Types> && ...)
|
|
&& (is_swappable_v<_Types> && ...))>
|
|
swap(variant<_Types...>&, variant<_Types...>&) = delete;
|
|
|
|
class bad_variant_access : public exception
|
|
{
|
|
public:
|
|
bad_variant_access() noexcept : _M_reason("Unknown reason") { }
|
|
const char* what() const noexcept override
|
|
{ return _M_reason; }
|
|
|
|
private:
|
|
bad_variant_access(const char* __reason) : _M_reason(__reason) { }
|
|
|
|
const char* _M_reason;
|
|
|
|
friend void __throw_bad_variant_access(const char* __what);
|
|
};
|
|
|
|
inline void
|
|
__throw_bad_variant_access(const char* __what)
|
|
{ _GLIBCXX_THROW_OR_ABORT(bad_variant_access(__what)); }
|
|
|
|
template<typename... _Types>
|
|
class variant
|
|
: private __detail::__variant::_Variant_base<_Types...>,
|
|
private _Enable_default_constructor<
|
|
__detail::__variant::_Traits<_Types...>::_S_default_ctor,
|
|
variant<_Types...>>,
|
|
private _Enable_copy_move<
|
|
__detail::__variant::_Traits<_Types...>::_S_copy_ctor,
|
|
__detail::__variant::_Traits<_Types...>::_S_copy_assign,
|
|
__detail::__variant::_Traits<_Types...>::_S_move_ctor,
|
|
__detail::__variant::_Traits<_Types...>::_S_move_assign,
|
|
variant<_Types...>>
|
|
{
|
|
private:
|
|
static_assert(sizeof...(_Types) > 0,
|
|
"variant must have at least one alternative");
|
|
static_assert(!(std::is_reference_v<_Types> || ...),
|
|
"variant must have no reference alternative");
|
|
static_assert(!(std::is_void_v<_Types> || ...),
|
|
"variant must have no void alternative");
|
|
|
|
using _Base = __detail::__variant::_Variant_base<_Types...>;
|
|
using _Default_ctor_enabler =
|
|
_Enable_default_constructor<
|
|
__detail::__variant::_Traits<_Types...>::_S_default_ctor,
|
|
variant<_Types...>>;
|
|
|
|
template<typename _Tp>
|
|
static constexpr bool
|
|
__exactly_once = __detail::__variant::__exactly_once<_Tp, _Types...>;
|
|
|
|
template<typename _Tp>
|
|
static constexpr size_t __accepted_index =
|
|
__detail::__variant::__accepted_index<_Tp&&, variant>::value;
|
|
|
|
template<size_t _Np, bool = _Np < sizeof...(_Types)>
|
|
struct __to_type_impl;
|
|
|
|
template<size_t _Np>
|
|
struct __to_type_impl<_Np, true>
|
|
{ using type = variant_alternative_t<_Np, variant>; };
|
|
|
|
template<size_t _Np>
|
|
using __to_type = typename __to_type_impl<_Np>::type;
|
|
|
|
template<typename _Tp>
|
|
using __accepted_type = __to_type<__accepted_index<_Tp>>;
|
|
|
|
template<typename _Tp>
|
|
static constexpr size_t __index_of =
|
|
__detail::__variant::__index_of_v<_Tp, _Types...>;
|
|
|
|
using _Traits = __detail::__variant::_Traits<_Types...>;
|
|
|
|
public:
|
|
variant() = default;
|
|
variant(const variant& __rhs) = default;
|
|
variant(variant&&) = default;
|
|
variant& operator=(const variant&) = default;
|
|
variant& operator=(variant&&) = default;
|
|
~variant() = default;
|
|
|
|
template<typename _Tp,
|
|
typename = enable_if_t<!is_same_v<decay_t<_Tp>, variant>>,
|
|
typename = enable_if_t<(sizeof...(_Types)>0)>,
|
|
typename = enable_if_t<__exactly_once<__accepted_type<_Tp&&>>
|
|
&& is_constructible_v<__accepted_type<_Tp&&>, _Tp&&>>>
|
|
constexpr
|
|
variant(_Tp&& __t)
|
|
noexcept(is_nothrow_constructible_v<__accepted_type<_Tp&&>, _Tp&&>)
|
|
: variant(in_place_index<__accepted_index<_Tp&&>>,
|
|
std::forward<_Tp>(__t))
|
|
{ __glibcxx_assert(holds_alternative<__accepted_type<_Tp&&>>(*this)); }
|
|
|
|
template<typename _Tp, typename... _Args,
|
|
typename = enable_if_t<__exactly_once<_Tp>
|
|
&& is_constructible_v<_Tp, _Args&&...>>>
|
|
constexpr explicit
|
|
variant(in_place_type_t<_Tp>, _Args&&... __args)
|
|
: variant(in_place_index<__index_of<_Tp>>,
|
|
std::forward<_Args>(__args)...)
|
|
{ __glibcxx_assert(holds_alternative<_Tp>(*this)); }
|
|
|
|
template<typename _Tp, typename _Up, typename... _Args,
|
|
typename = enable_if_t<__exactly_once<_Tp>
|
|
&& is_constructible_v<
|
|
_Tp, initializer_list<_Up>&, _Args&&...>>>
|
|
constexpr explicit
|
|
variant(in_place_type_t<_Tp>, initializer_list<_Up> __il,
|
|
_Args&&... __args)
|
|
: variant(in_place_index<__index_of<_Tp>>, __il,
|
|
std::forward<_Args>(__args)...)
|
|
{ __glibcxx_assert(holds_alternative<_Tp>(*this)); }
|
|
|
|
template<size_t _Np, typename... _Args,
|
|
typename = enable_if_t<
|
|
is_constructible_v<__to_type<_Np>, _Args&&...>>>
|
|
constexpr explicit
|
|
variant(in_place_index_t<_Np>, _Args&&... __args)
|
|
: _Base(in_place_index<_Np>, std::forward<_Args>(__args)...),
|
|
_Default_ctor_enabler(_Enable_default_constructor_tag{})
|
|
{ __glibcxx_assert(index() == _Np); }
|
|
|
|
template<size_t _Np, typename _Up, typename... _Args,
|
|
typename = enable_if_t<is_constructible_v<__to_type<_Np>,
|
|
initializer_list<_Up>&, _Args&&...>>>
|
|
constexpr explicit
|
|
variant(in_place_index_t<_Np>, initializer_list<_Up> __il,
|
|
_Args&&... __args)
|
|
: _Base(in_place_index<_Np>, __il, std::forward<_Args>(__args)...),
|
|
_Default_ctor_enabler(_Enable_default_constructor_tag{})
|
|
{ __glibcxx_assert(index() == _Np); }
|
|
|
|
template<typename _Tp>
|
|
enable_if_t<__exactly_once<__accepted_type<_Tp&&>>
|
|
&& is_constructible_v<__accepted_type<_Tp&&>, _Tp&&>
|
|
&& is_assignable_v<__accepted_type<_Tp&&>&, _Tp&&>
|
|
&& !is_same_v<decay_t<_Tp>, variant>, variant&>
|
|
operator=(_Tp&& __rhs)
|
|
noexcept(is_nothrow_assignable_v<__accepted_type<_Tp&&>&, _Tp&&>
|
|
&& is_nothrow_constructible_v<__accepted_type<_Tp&&>, _Tp&&>)
|
|
{
|
|
constexpr auto __index = __accepted_index<_Tp&&>;
|
|
if (index() == __index)
|
|
std::get<__index>(*this) = std::forward<_Tp>(__rhs);
|
|
else
|
|
this->emplace<__index>(std::forward<_Tp>(__rhs));
|
|
__glibcxx_assert(holds_alternative<__accepted_type<_Tp&&>>(*this));
|
|
return *this;
|
|
}
|
|
|
|
template<typename _Tp, typename... _Args>
|
|
enable_if_t<is_constructible_v<_Tp, _Args...> && __exactly_once<_Tp>,
|
|
_Tp&>
|
|
emplace(_Args&&... __args)
|
|
{
|
|
auto& ret =
|
|
this->emplace<__index_of<_Tp>>(std::forward<_Args>(__args)...);
|
|
__glibcxx_assert(holds_alternative<_Tp>(*this));
|
|
return ret;
|
|
}
|
|
|
|
template<typename _Tp, typename _Up, typename... _Args>
|
|
enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>
|
|
&& __exactly_once<_Tp>,
|
|
_Tp&>
|
|
emplace(initializer_list<_Up> __il, _Args&&... __args)
|
|
{
|
|
auto& ret =
|
|
this->emplace<__index_of<_Tp>>(__il,
|
|
std::forward<_Args>(__args)...);
|
|
__glibcxx_assert(holds_alternative<_Tp>(*this));
|
|
return ret;
|
|
}
|
|
|
|
template<size_t _Np, typename... _Args>
|
|
enable_if_t<is_constructible_v<variant_alternative_t<_Np, variant>,
|
|
_Args...>,
|
|
variant_alternative_t<_Np, variant>&>
|
|
emplace(_Args&&... __args)
|
|
{
|
|
static_assert(_Np < sizeof...(_Types),
|
|
"The index should be in [0, number of alternatives)");
|
|
this->~variant();
|
|
__try
|
|
{
|
|
::new (this) variant(in_place_index<_Np>,
|
|
std::forward<_Args>(__args)...);
|
|
}
|
|
__catch (...)
|
|
{
|
|
this->_M_index = variant_npos;
|
|
__throw_exception_again;
|
|
}
|
|
__glibcxx_assert(index() == _Np);
|
|
return std::get<_Np>(*this);
|
|
}
|
|
|
|
template<size_t _Np, typename _Up, typename... _Args>
|
|
enable_if_t<is_constructible_v<variant_alternative_t<_Np, variant>,
|
|
initializer_list<_Up>&, _Args...>,
|
|
variant_alternative_t<_Np, variant>&>
|
|
emplace(initializer_list<_Up> __il, _Args&&... __args)
|
|
{
|
|
static_assert(_Np < sizeof...(_Types),
|
|
"The index should be in [0, number of alternatives)");
|
|
this->~variant();
|
|
__try
|
|
{
|
|
::new (this) variant(in_place_index<_Np>, __il,
|
|
std::forward<_Args>(__args)...);
|
|
}
|
|
__catch (...)
|
|
{
|
|
this->_M_index = variant_npos;
|
|
__throw_exception_again;
|
|
}
|
|
__glibcxx_assert(index() == _Np);
|
|
return std::get<_Np>(*this);
|
|
}
|
|
|
|
constexpr bool valueless_by_exception() const noexcept
|
|
{ return !this->_M_valid(); }
|
|
|
|
constexpr size_t index() const noexcept
|
|
{
|
|
if (this->_M_index ==
|
|
typename _Base::__index_type(variant_npos))
|
|
return variant_npos;
|
|
return this->_M_index;
|
|
}
|
|
|
|
void
|
|
swap(variant& __rhs)
|
|
noexcept((__is_nothrow_swappable<_Types>::value && ...)
|
|
&& is_nothrow_move_constructible_v<variant>)
|
|
{
|
|
if (this->index() == __rhs.index())
|
|
{
|
|
if (this->_M_valid())
|
|
{
|
|
static constexpr void (*_S_vtable[])(void*, void*) =
|
|
{ &__detail::__variant::__erased_swap<_Types&, _Types&>... };
|
|
_S_vtable[__rhs._M_index](this->_M_storage(),
|
|
__rhs._M_storage());
|
|
}
|
|
}
|
|
else if (!this->_M_valid())
|
|
{
|
|
this->_M_destructive_move(std::move(__rhs));
|
|
__rhs._M_reset();
|
|
}
|
|
else if (!__rhs._M_valid())
|
|
{
|
|
__rhs._M_destructive_move(std::move(*this));
|
|
this->_M_reset();
|
|
}
|
|
else
|
|
{
|
|
auto __tmp = std::move(__rhs);
|
|
__rhs._M_destructive_move(std::move(*this));
|
|
this->_M_destructive_move(std::move(__tmp));
|
|
}
|
|
}
|
|
|
|
private:
|
|
#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP, __NAME) \
|
|
template<size_t... __indices> \
|
|
static constexpr bool \
|
|
(*_S_erased_##__NAME[])(const variant&, const variant&) = \
|
|
{ &__detail::__variant::__erased_##__NAME< \
|
|
const variant&, __indices>... }; \
|
|
template<size_t... __indices> \
|
|
constexpr inline bool \
|
|
_M_##__NAME(const variant& __rhs, \
|
|
std::index_sequence<__indices...>) const \
|
|
{ \
|
|
auto __lhs_index = this->index(); \
|
|
auto __rhs_index = __rhs.index(); \
|
|
if (__lhs_index != __rhs_index || valueless_by_exception()) \
|
|
/* Modulo addition. */ \
|
|
return __lhs_index + 1 __OP __rhs_index + 1; \
|
|
return _S_erased_##__NAME<__indices...>[__lhs_index](*this, __rhs); \
|
|
}
|
|
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(<=, less_equal)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(==, equal)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(!=, not_equal)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(>=, greater_equal)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(>, greater)
|
|
|
|
#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
|
|
|
|
template<size_t _Np, typename _Vp>
|
|
friend constexpr decltype(auto) __detail::__variant::__get(_Vp&& __v);
|
|
|
|
template<typename _Vp>
|
|
friend void* __detail::__variant::__get_storage(_Vp&& __v);
|
|
|
|
#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP) \
|
|
template<typename... _Tp> \
|
|
friend constexpr bool \
|
|
operator __OP(const variant<_Tp...>& __lhs, \
|
|
const variant<_Tp...>& __rhs);
|
|
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(<)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(<=)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(==)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(!=)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(>=)
|
|
_VARIANT_RELATION_FUNCTION_TEMPLATE(>)
|
|
|
|
#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
|
|
};
|
|
|
|
template<size_t _Np, typename... _Types>
|
|
constexpr variant_alternative_t<_Np, variant<_Types...>>&
|
|
get(variant<_Types...>& __v)
|
|
{
|
|
static_assert(_Np < sizeof...(_Types),
|
|
"The index should be in [0, number of alternatives)");
|
|
if (__v.index() != _Np)
|
|
__throw_bad_variant_access("Unexpected index");
|
|
return __detail::__variant::__get<_Np>(__v);
|
|
}
|
|
|
|
template<size_t _Np, typename... _Types>
|
|
constexpr variant_alternative_t<_Np, variant<_Types...>>&&
|
|
get(variant<_Types...>&& __v)
|
|
{
|
|
static_assert(_Np < sizeof...(_Types),
|
|
"The index should be in [0, number of alternatives)");
|
|
if (__v.index() != _Np)
|
|
__throw_bad_variant_access("Unexpected index");
|
|
return __detail::__variant::__get<_Np>(std::move(__v));
|
|
}
|
|
|
|
template<size_t _Np, typename... _Types>
|
|
constexpr const variant_alternative_t<_Np, variant<_Types...>>&
|
|
get(const variant<_Types...>& __v)
|
|
{
|
|
static_assert(_Np < sizeof...(_Types),
|
|
"The index should be in [0, number of alternatives)");
|
|
if (__v.index() != _Np)
|
|
__throw_bad_variant_access("Unexpected index");
|
|
return __detail::__variant::__get<_Np>(__v);
|
|
}
|
|
|
|
template<size_t _Np, typename... _Types>
|
|
constexpr const variant_alternative_t<_Np, variant<_Types...>>&&
|
|
get(const variant<_Types...>&& __v)
|
|
{
|
|
static_assert(_Np < sizeof...(_Types),
|
|
"The index should be in [0, number of alternatives)");
|
|
if (__v.index() != _Np)
|
|
__throw_bad_variant_access("Unexpected index");
|
|
return __detail::__variant::__get<_Np>(std::move(__v));
|
|
}
|
|
|
|
template<typename _Visitor, typename... _Variants>
|
|
constexpr decltype(auto)
|
|
visit(_Visitor&& __visitor, _Variants&&... __variants)
|
|
{
|
|
if ((__variants.valueless_by_exception() || ...))
|
|
__throw_bad_variant_access("Unexpected index");
|
|
|
|
using _Result_type =
|
|
decltype(std::forward<_Visitor>(__visitor)(
|
|
get<0>(std::forward<_Variants>(__variants))...));
|
|
|
|
constexpr auto& __vtable = __detail::__variant::__gen_vtable<
|
|
_Result_type, _Visitor&&, _Variants&&...>::_S_vtable;
|
|
|
|
auto __func_ptr = __vtable._M_access(__variants.index()...);
|
|
return (*__func_ptr)(std::forward<_Visitor>(__visitor),
|
|
std::forward<_Variants>(__variants)...);
|
|
}
|
|
|
|
template<bool, typename... _Types>
|
|
struct __variant_hash_call_base_impl
|
|
{
|
|
size_t
|
|
operator()(const variant<_Types...>& __t) const
|
|
noexcept((is_nothrow_invocable_v<hash<decay_t<_Types>>, _Types> && ...))
|
|
{
|
|
if (!__t.valueless_by_exception())
|
|
{
|
|
namespace __edv = __detail::__variant;
|
|
static constexpr size_t (*_S_vtable[])(void*) =
|
|
{ &__edv::__erased_hash<const _Types&>... };
|
|
return hash<size_t>{}(__t.index())
|
|
+ _S_vtable[__t.index()](__edv::__get_storage(__t));
|
|
}
|
|
return hash<size_t>{}(__t.index());
|
|
}
|
|
};
|
|
|
|
template<typename... _Types>
|
|
struct __variant_hash_call_base_impl<false, _Types...> {};
|
|
|
|
template<typename... _Types>
|
|
using __variant_hash_call_base =
|
|
__variant_hash_call_base_impl<(__poison_hash<remove_const_t<_Types>>::
|
|
__enable_hash_call &&...), _Types...>;
|
|
|
|
template<typename... _Types>
|
|
struct hash<variant<_Types...>>
|
|
: private __detail::__variant::_Variant_hash_base<
|
|
variant<_Types...>, std::index_sequence_for<_Types...>>,
|
|
public __variant_hash_call_base<_Types...>
|
|
{
|
|
using result_type [[__deprecated__]] = size_t;
|
|
using argument_type [[__deprecated__]] = variant<_Types...>;
|
|
};
|
|
|
|
template<>
|
|
struct hash<monostate>
|
|
{
|
|
using result_type [[__deprecated__]] = size_t;
|
|
using argument_type [[__deprecated__]] = monostate;
|
|
|
|
size_t
|
|
operator()(const monostate& __t) const noexcept
|
|
{
|
|
constexpr size_t __magic_monostate_hash = -7777;
|
|
return __magic_monostate_hash;
|
|
}
|
|
};
|
|
|
|
template<typename... _Types>
|
|
struct __is_fast_hash<hash<variant<_Types...>>>
|
|
: bool_constant<(__is_fast_hash<_Types>::value && ...)>
|
|
{ };
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace std
|
|
|
|
#endif // C++17
|
|
|
|
#endif // _GLIBCXX_VARIANT
|