201 lines
6.7 KiB
C++
201 lines
6.7 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___MEMORY_COMPRESSED_PAIR_H
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#define _LIBCPP___MEMORY_COMPRESSED_PAIR_H
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#include <__config>
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#include <tuple> // needed in c++03 for some constructors
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#include <type_traits>
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#include <utility>
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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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_LIBCPP_BEGIN_NAMESPACE_STD
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// Tag used to default initialize one or both of the pair's elements.
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struct __default_init_tag {};
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struct __value_init_tag {};
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template <class _Tp, int _Idx,
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bool _CanBeEmptyBase =
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is_empty<_Tp>::value && !__libcpp_is_final<_Tp>::value>
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struct __compressed_pair_elem {
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typedef _Tp _ParamT;
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typedef _Tp& reference;
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typedef const _Tp& const_reference;
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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__compressed_pair_elem(__default_init_tag) {}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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__compressed_pair_elem(__value_init_tag) : __value_() {}
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template <class _Up, class = typename enable_if<
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!is_same<__compressed_pair_elem, typename decay<_Up>::type>::value
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>::type>
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_LIBCPP_INLINE_VISIBILITY
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_LIBCPP_CONSTEXPR explicit
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__compressed_pair_elem(_Up&& __u)
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: __value_(_VSTD::forward<_Up>(__u))
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{
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}
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#ifndef _LIBCPP_CXX03_LANG
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template <class... _Args, size_t... _Indexes>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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__compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args,
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__tuple_indices<_Indexes...>)
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: __value_(_VSTD::forward<_Args>(_VSTD::get<_Indexes>(__args))...) {}
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#endif
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_LIBCPP_INLINE_VISIBILITY reference __get() _NOEXCEPT { return __value_; }
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_LIBCPP_INLINE_VISIBILITY
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const_reference __get() const _NOEXCEPT { return __value_; }
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private:
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_Tp __value_;
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};
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template <class _Tp, int _Idx>
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struct __compressed_pair_elem<_Tp, _Idx, true> : private _Tp {
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typedef _Tp _ParamT;
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typedef _Tp& reference;
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typedef const _Tp& const_reference;
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typedef _Tp __value_type;
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __compressed_pair_elem() = default;
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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__compressed_pair_elem(__default_init_tag) {}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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__compressed_pair_elem(__value_init_tag) : __value_type() {}
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template <class _Up, class = typename enable_if<
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!is_same<__compressed_pair_elem, typename decay<_Up>::type>::value
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>::type>
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_LIBCPP_INLINE_VISIBILITY
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_LIBCPP_CONSTEXPR explicit
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__compressed_pair_elem(_Up&& __u)
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: __value_type(_VSTD::forward<_Up>(__u))
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{}
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#ifndef _LIBCPP_CXX03_LANG
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template <class... _Args, size_t... _Indexes>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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__compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args,
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__tuple_indices<_Indexes...>)
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: __value_type(_VSTD::forward<_Args>(_VSTD::get<_Indexes>(__args))...) {}
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#endif
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_LIBCPP_INLINE_VISIBILITY reference __get() _NOEXCEPT { return *this; }
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_LIBCPP_INLINE_VISIBILITY
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const_reference __get() const _NOEXCEPT { return *this; }
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};
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template <class _T1, class _T2>
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class __compressed_pair : private __compressed_pair_elem<_T1, 0>,
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private __compressed_pair_elem<_T2, 1> {
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public:
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// NOTE: This static assert should never fire because __compressed_pair
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// is *almost never* used in a scenario where it's possible for T1 == T2.
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// (The exception is std::function where it is possible that the function
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// object and the allocator have the same type).
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static_assert((!is_same<_T1, _T2>::value),
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"__compressed_pair cannot be instantiated when T1 and T2 are the same type; "
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"The current implementation is NOT ABI-compatible with the previous "
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"implementation for this configuration");
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typedef _LIBCPP_NODEBUG_TYPE __compressed_pair_elem<_T1, 0> _Base1;
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typedef _LIBCPP_NODEBUG_TYPE __compressed_pair_elem<_T2, 1> _Base2;
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template <bool _Dummy = true,
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class = typename enable_if<
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__dependent_type<is_default_constructible<_T1>, _Dummy>::value &&
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__dependent_type<is_default_constructible<_T2>, _Dummy>::value
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>::type
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>
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_LIBCPP_INLINE_VISIBILITY
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_LIBCPP_CONSTEXPR __compressed_pair() : _Base1(__value_init_tag()), _Base2(__value_init_tag()) {}
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template <class _U1, class _U2>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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__compressed_pair(_U1&& __t1, _U2&& __t2)
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: _Base1(_VSTD::forward<_U1>(__t1)), _Base2(_VSTD::forward<_U2>(__t2)) {}
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#ifndef _LIBCPP_CXX03_LANG
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template <class... _Args1, class... _Args2>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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__compressed_pair(piecewise_construct_t __pc, tuple<_Args1...> __first_args,
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tuple<_Args2...> __second_args)
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: _Base1(__pc, _VSTD::move(__first_args),
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typename __make_tuple_indices<sizeof...(_Args1)>::type()),
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_Base2(__pc, _VSTD::move(__second_args),
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typename __make_tuple_indices<sizeof...(_Args2)>::type()) {}
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#endif
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_LIBCPP_INLINE_VISIBILITY
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typename _Base1::reference first() _NOEXCEPT {
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return static_cast<_Base1&>(*this).__get();
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}
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_LIBCPP_INLINE_VISIBILITY
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typename _Base1::const_reference first() const _NOEXCEPT {
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return static_cast<_Base1 const&>(*this).__get();
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}
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_LIBCPP_INLINE_VISIBILITY
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typename _Base2::reference second() _NOEXCEPT {
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return static_cast<_Base2&>(*this).__get();
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}
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_LIBCPP_INLINE_VISIBILITY
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typename _Base2::const_reference second() const _NOEXCEPT {
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return static_cast<_Base2 const&>(*this).__get();
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}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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static _Base1* __get_first_base(__compressed_pair* __pair) _NOEXCEPT {
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return static_cast<_Base1*>(__pair);
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}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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static _Base2* __get_second_base(__compressed_pair* __pair) _NOEXCEPT {
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return static_cast<_Base2*>(__pair);
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}
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_LIBCPP_INLINE_VISIBILITY
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void swap(__compressed_pair& __x)
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_NOEXCEPT_(__is_nothrow_swappable<_T1>::value &&
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__is_nothrow_swappable<_T2>::value)
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{
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using _VSTD::swap;
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swap(first(), __x.first());
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swap(second(), __x.second());
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}
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};
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template <class _T1, class _T2>
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inline _LIBCPP_INLINE_VISIBILITY
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void swap(__compressed_pair<_T1, _T2>& __x, __compressed_pair<_T1, _T2>& __y)
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_NOEXCEPT_(__is_nothrow_swappable<_T1>::value &&
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__is_nothrow_swappable<_T2>::value) {
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__x.swap(__y);
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}
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___MEMORY_COMPRESSED_PAIR_H
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