196 lines
6.7 KiB
C++
196 lines
6.7 KiB
C++
// Uses-allocator Construction -*- C++ -*-
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// Copyright (C) 2010-2021 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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#ifndef _USES_ALLOCATOR_H
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#define _USES_ALLOCATOR_H 1
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#if __cplusplus < 201103L
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# include <bits/c++0x_warning.h>
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#else
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#include <type_traits>
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#include <bits/move.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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// This is used for std::experimental::erased_type from Library Fundamentals.
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struct __erased_type { };
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// This also supports the "type-erased allocator" protocol from the
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// Library Fundamentals TS, where allocator_type is erased_type.
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// The second condition will always be false for types not using the TS.
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template<typename _Alloc, typename _Tp>
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using __is_erased_or_convertible
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= __or_<is_convertible<_Alloc, _Tp>, is_same<_Tp, __erased_type>>;
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/// [allocator.tag]
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struct allocator_arg_t { explicit allocator_arg_t() = default; };
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_GLIBCXX17_INLINE constexpr allocator_arg_t allocator_arg =
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allocator_arg_t();
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template<typename _Tp, typename _Alloc, typename = __void_t<>>
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struct __uses_allocator_helper
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: false_type { };
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template<typename _Tp, typename _Alloc>
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struct __uses_allocator_helper<_Tp, _Alloc,
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__void_t<typename _Tp::allocator_type>>
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: __is_erased_or_convertible<_Alloc, typename _Tp::allocator_type>::type
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{ };
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/// [allocator.uses.trait]
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template<typename _Tp, typename _Alloc>
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struct uses_allocator
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: __uses_allocator_helper<_Tp, _Alloc>::type
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{ };
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struct __uses_alloc_base { };
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struct __uses_alloc0 : __uses_alloc_base
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{
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struct _Sink { void _GLIBCXX20_CONSTEXPR operator=(const void*) { } } _M_a;
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};
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template<typename _Alloc>
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struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; };
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template<typename _Alloc>
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struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; };
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template<bool, typename _Tp, typename _Alloc, typename... _Args>
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struct __uses_alloc;
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template<typename _Tp, typename _Alloc, typename... _Args>
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struct __uses_alloc<true, _Tp, _Alloc, _Args...>
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: conditional<
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is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>::value,
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__uses_alloc1<_Alloc>,
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__uses_alloc2<_Alloc>>::type
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{
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 2586. Wrong value category used in scoped_allocator_adaptor::construct
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static_assert(__or_<
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is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>,
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is_constructible<_Tp, _Args..., const _Alloc&>>::value,
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"construction with an allocator must be possible"
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" if uses_allocator is true");
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};
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template<typename _Tp, typename _Alloc, typename... _Args>
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struct __uses_alloc<false, _Tp, _Alloc, _Args...>
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: __uses_alloc0 { };
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template<typename _Tp, typename _Alloc, typename... _Args>
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using __uses_alloc_t =
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__uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp, _Alloc, _Args...>;
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template<typename _Tp, typename _Alloc, typename... _Args>
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_GLIBCXX20_CONSTEXPR
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inline __uses_alloc_t<_Tp, _Alloc, _Args...>
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__use_alloc(const _Alloc& __a)
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{
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__uses_alloc_t<_Tp, _Alloc, _Args...> __ret;
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__ret._M_a = std::__addressof(__a);
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return __ret;
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}
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template<typename _Tp, typename _Alloc, typename... _Args>
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void
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__use_alloc(const _Alloc&&) = delete;
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#if __cplusplus > 201402L
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template <typename _Tp, typename _Alloc>
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inline constexpr bool uses_allocator_v =
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uses_allocator<_Tp, _Alloc>::value;
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#endif // C++17
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template<template<typename...> class _Predicate,
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typename _Tp, typename _Alloc, typename... _Args>
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struct __is_uses_allocator_predicate
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: conditional<uses_allocator<_Tp, _Alloc>::value,
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__or_<_Predicate<_Tp, allocator_arg_t, _Alloc, _Args...>,
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_Predicate<_Tp, _Args..., _Alloc>>,
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_Predicate<_Tp, _Args...>>::type { };
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template<typename _Tp, typename _Alloc, typename... _Args>
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struct __is_uses_allocator_constructible
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: __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...>
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{ };
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#if __cplusplus >= 201402L
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template<typename _Tp, typename _Alloc, typename... _Args>
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_GLIBCXX17_INLINE constexpr bool __is_uses_allocator_constructible_v =
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__is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value;
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#endif // C++14
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template<typename _Tp, typename _Alloc, typename... _Args>
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struct __is_nothrow_uses_allocator_constructible
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: __is_uses_allocator_predicate<is_nothrow_constructible,
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_Tp, _Alloc, _Args...>
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{ };
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#if __cplusplus >= 201402L
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template<typename _Tp, typename _Alloc, typename... _Args>
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_GLIBCXX17_INLINE constexpr bool
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__is_nothrow_uses_allocator_constructible_v =
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__is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value;
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#endif // C++14
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template<typename _Tp, typename... _Args>
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void __uses_allocator_construct_impl(__uses_alloc0 __a, _Tp* __ptr,
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_Args&&... __args)
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{ ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)...); }
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template<typename _Tp, typename _Alloc, typename... _Args>
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void __uses_allocator_construct_impl(__uses_alloc1<_Alloc> __a, _Tp* __ptr,
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_Args&&... __args)
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{
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::new ((void*)__ptr) _Tp(allocator_arg, *__a._M_a,
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std::forward<_Args>(__args)...);
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}
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template<typename _Tp, typename _Alloc, typename... _Args>
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void __uses_allocator_construct_impl(__uses_alloc2<_Alloc> __a, _Tp* __ptr,
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_Args&&... __args)
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{ ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)..., *__a._M_a); }
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template<typename _Tp, typename _Alloc, typename... _Args>
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void __uses_allocator_construct(const _Alloc& __a, _Tp* __ptr,
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_Args&&... __args)
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{
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std::__uses_allocator_construct_impl(
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std::__use_alloc<_Tp, _Alloc, _Args...>(__a), __ptr,
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std::forward<_Args>(__args)...);
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}
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif
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#endif
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