1fe6060f1SDimitry Andric // -*- C++ -*- 2fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 3fe6060f1SDimitry Andric // 4fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7fe6060f1SDimitry Andric // 8fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 9fe6060f1SDimitry Andric 10fe6060f1SDimitry Andric #ifndef _LIBCPP___MEMORY_COMPRESSED_PAIR_H 11fe6060f1SDimitry Andric #define _LIBCPP___MEMORY_COMPRESSED_PAIR_H 12fe6060f1SDimitry Andric 13fe6060f1SDimitry Andric #include <__config> 14bdd1243dSDimitry Andric #include <__fwd/get.h> 15bdd1243dSDimitry Andric #include <__fwd/tuple.h> 1606c3fb27SDimitry Andric #include <__tuple/tuple_indices.h> 17bdd1243dSDimitry Andric #include <__type_traits/decay.h> 18bdd1243dSDimitry Andric #include <__type_traits/dependent_type.h> 19bdd1243dSDimitry Andric #include <__type_traits/enable_if.h> 20bdd1243dSDimitry Andric #include <__type_traits/is_default_constructible.h> 21bdd1243dSDimitry Andric #include <__type_traits/is_empty.h> 22bdd1243dSDimitry Andric #include <__type_traits/is_final.h> 23bdd1243dSDimitry Andric #include <__type_traits/is_same.h> 24bdd1243dSDimitry Andric #include <__type_traits/is_swappable.h> 25fe6060f1SDimitry Andric #include <__utility/forward.h> 2681ad6265SDimitry Andric #include <__utility/move.h> 27bdd1243dSDimitry Andric #include <__utility/piecewise_construct.h> 28bdd1243dSDimitry Andric #include <cstddef> 29fe6060f1SDimitry Andric 30fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 31fe6060f1SDimitry Andric # pragma GCC system_header 32fe6060f1SDimitry Andric #endif 33fe6060f1SDimitry Andric 3406c3fb27SDimitry Andric _LIBCPP_PUSH_MACROS 3506c3fb27SDimitry Andric #include <__undef_macros> 3606c3fb27SDimitry Andric 37fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 38fe6060f1SDimitry Andric 39fe6060f1SDimitry Andric // Tag used to default initialize one or both of the pair's elements. 40fe6060f1SDimitry Andric struct __default_init_tag {}; 41fe6060f1SDimitry Andric struct __value_init_tag {}; 42fe6060f1SDimitry Andric 4381ad6265SDimitry Andric template <class _Tp, int _Idx, bool _CanBeEmptyBase = is_empty<_Tp>::value && !__libcpp_is_final<_Tp>::value> 44fe6060f1SDimitry Andric struct __compressed_pair_elem { 4581ad6265SDimitry Andric using _ParamT = _Tp; 4681ad6265SDimitry Andric using reference = _Tp&; 4781ad6265SDimitry Andric using const_reference = const _Tp&; 48fe6060f1SDimitry Andric __compressed_pair_elem__compressed_pair_elem4981ad6265SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(__default_init_tag) {} __compressed_pair_elem__compressed_pair_elem5081ad6265SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(__value_init_tag) : __value_() {} 51fe6060f1SDimitry Andric 5206c3fb27SDimitry Andric template <class _Up, class = __enable_if_t<!is_same<__compressed_pair_elem, __decay_t<_Up> >::value> > __compressed_pair_elem__compressed_pair_elem53*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(_Up&& __u) 54*cb14a3feSDimitry Andric : __value_(std::forward<_Up>(__u)) {} 55fe6060f1SDimitry Andric 56fe6060f1SDimitry Andric #ifndef _LIBCPP_CXX03_LANG 5781ad6265SDimitry Andric template <class... _Args, size_t... _Indices> __compressed_pair_elem__compressed_pair_elem58*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 explicit __compressed_pair_elem( 59*cb14a3feSDimitry Andric piecewise_construct_t, tuple<_Args...> __args, __tuple_indices<_Indices...>) 6081ad6265SDimitry Andric : __value_(std::forward<_Args>(std::get<_Indices>(__args))...) {} 61fe6060f1SDimitry Andric #endif 62fe6060f1SDimitry Andric __get__compressed_pair_elem63bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference __get() _NOEXCEPT { return __value_; } __get__compressed_pair_elem6481ad6265SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const_reference __get() const _NOEXCEPT { return __value_; } 65fe6060f1SDimitry Andric 66fe6060f1SDimitry Andric private: 67fe6060f1SDimitry Andric _Tp __value_; 68fe6060f1SDimitry Andric }; 69fe6060f1SDimitry Andric 70fe6060f1SDimitry Andric template <class _Tp, int _Idx> 71fe6060f1SDimitry Andric struct __compressed_pair_elem<_Tp, _Idx, true> : private _Tp { 7281ad6265SDimitry Andric using _ParamT = _Tp; 7381ad6265SDimitry Andric using reference = _Tp&; 7481ad6265SDimitry Andric using const_reference = const _Tp&; 7581ad6265SDimitry Andric using __value_type = _Tp; 76fe6060f1SDimitry Andric 7781ad6265SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem() = default; 7881ad6265SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(__default_init_tag) {} 7981ad6265SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(__value_init_tag) : __value_type() {} 80fe6060f1SDimitry Andric 8106c3fb27SDimitry Andric template <class _Up, class = __enable_if_t<!is_same<__compressed_pair_elem, __decay_t<_Up> >::value> > 82*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair_elem(_Up&& __u) 83*cb14a3feSDimitry Andric : __value_type(std::forward<_Up>(__u)) {} 84fe6060f1SDimitry Andric 85fe6060f1SDimitry Andric #ifndef _LIBCPP_CXX03_LANG 8681ad6265SDimitry Andric template <class... _Args, size_t... _Indices> 87bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 8881ad6265SDimitry Andric __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args, __tuple_indices<_Indices...>) 8981ad6265SDimitry Andric : __value_type(std::forward<_Args>(std::get<_Indices>(__args))...) {} 90fe6060f1SDimitry Andric #endif 91fe6060f1SDimitry Andric 92bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 reference __get() _NOEXCEPT { return *this; } 9381ad6265SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const_reference __get() const _NOEXCEPT { return *this; } 94fe6060f1SDimitry Andric }; 95fe6060f1SDimitry Andric 96fe6060f1SDimitry Andric template <class _T1, class _T2> 97*cb14a3feSDimitry Andric class __compressed_pair : private __compressed_pair_elem<_T1, 0>, private __compressed_pair_elem<_T2, 1> { 98fe6060f1SDimitry Andric public: 99fe6060f1SDimitry Andric // NOTE: This static assert should never fire because __compressed_pair 100fe6060f1SDimitry Andric // is *almost never* used in a scenario where it's possible for T1 == T2. 101fe6060f1SDimitry Andric // (The exception is std::function where it is possible that the function 102fe6060f1SDimitry Andric // object and the allocator have the same type). 103*cb14a3feSDimitry Andric static_assert( 104*cb14a3feSDimitry Andric (!is_same<_T1, _T2>::value), 105fe6060f1SDimitry Andric "__compressed_pair cannot be instantiated when T1 and T2 are the same type; " 10681ad6265SDimitry Andric "The current implementation is NOT ABI-compatible with the previous implementation for this configuration"); 107fe6060f1SDimitry Andric 10881ad6265SDimitry Andric using _Base1 _LIBCPP_NODEBUG = __compressed_pair_elem<_T1, 0>; 10981ad6265SDimitry Andric using _Base2 _LIBCPP_NODEBUG = __compressed_pair_elem<_T2, 1>; 110fe6060f1SDimitry Andric 111fe6060f1SDimitry Andric template <bool _Dummy = true, 112*cb14a3feSDimitry Andric class = __enable_if_t< __dependent_type<is_default_constructible<_T1>, _Dummy>::value && 113*cb14a3feSDimitry Andric __dependent_type<is_default_constructible<_T2>, _Dummy>::value > > 114*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair() 115*cb14a3feSDimitry Andric : _Base1(__value_init_tag()), _Base2(__value_init_tag()) {} 116fe6060f1SDimitry Andric 117fe6060f1SDimitry Andric template <class _U1, class _U2> 118*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __compressed_pair(_U1&& __t1, _U2&& __t2) 119*cb14a3feSDimitry Andric : _Base1(std::forward<_U1>(__t1)), _Base2(std::forward<_U2>(__t2)) {} 120fe6060f1SDimitry Andric 121fe6060f1SDimitry Andric #ifndef _LIBCPP_CXX03_LANG 122fe6060f1SDimitry Andric template <class... _Args1, class... _Args2> 123*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 explicit __compressed_pair( 124*cb14a3feSDimitry Andric piecewise_construct_t __pc, tuple<_Args1...> __first_args, tuple<_Args2...> __second_args) 12581ad6265SDimitry Andric : _Base1(__pc, std::move(__first_args), typename __make_tuple_indices<sizeof...(_Args1)>::type()), 12681ad6265SDimitry Andric _Base2(__pc, std::move(__second_args), typename __make_tuple_indices<sizeof...(_Args2)>::type()) {} 127fe6060f1SDimitry Andric #endif 128fe6060f1SDimitry Andric 129*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename _Base1::reference first() _NOEXCEPT { 130fe6060f1SDimitry Andric return static_cast<_Base1&>(*this).__get(); 131fe6060f1SDimitry Andric } 132fe6060f1SDimitry Andric 133*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR typename _Base1::const_reference first() const _NOEXCEPT { 134fe6060f1SDimitry Andric return static_cast<_Base1 const&>(*this).__get(); 135fe6060f1SDimitry Andric } 136fe6060f1SDimitry Andric 137*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename _Base2::reference second() _NOEXCEPT { 138fe6060f1SDimitry Andric return static_cast<_Base2&>(*this).__get(); 139fe6060f1SDimitry Andric } 140fe6060f1SDimitry Andric 141*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR typename _Base2::const_reference second() const _NOEXCEPT { 142fe6060f1SDimitry Andric return static_cast<_Base2 const&>(*this).__get(); 143fe6060f1SDimitry Andric } 144fe6060f1SDimitry Andric 145*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR static _Base1* __get_first_base(__compressed_pair* __pair) _NOEXCEPT { 146fe6060f1SDimitry Andric return static_cast<_Base1*>(__pair); 147fe6060f1SDimitry Andric } 148*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR static _Base2* __get_second_base(__compressed_pair* __pair) _NOEXCEPT { 149fe6060f1SDimitry Andric return static_cast<_Base2*>(__pair); 150fe6060f1SDimitry Andric } 151fe6060f1SDimitry Andric 152*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void swap(__compressed_pair& __x) 1530eae32dcSDimitry Andric _NOEXCEPT_(__is_nothrow_swappable<_T1>::value&& __is_nothrow_swappable<_T2>::value) { 15481ad6265SDimitry Andric using std::swap; 155fe6060f1SDimitry Andric swap(first(), __x.first()); 156fe6060f1SDimitry Andric swap(second(), __x.second()); 157fe6060f1SDimitry Andric } 158fe6060f1SDimitry Andric }; 159fe6060f1SDimitry Andric 160fe6060f1SDimitry Andric template <class _T1, class _T2> 161*cb14a3feSDimitry Andric inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void 162*cb14a3feSDimitry Andric swap(__compressed_pair<_T1, _T2>& __x, __compressed_pair<_T1, _T2>& __y) 1630eae32dcSDimitry Andric _NOEXCEPT_(__is_nothrow_swappable<_T1>::value&& __is_nothrow_swappable<_T2>::value) { 164fe6060f1SDimitry Andric __x.swap(__y); 165fe6060f1SDimitry Andric } 166fe6060f1SDimitry Andric 167fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 168fe6060f1SDimitry Andric 16906c3fb27SDimitry Andric _LIBCPP_POP_MACROS 17006c3fb27SDimitry Andric 171fe6060f1SDimitry Andric #endif // _LIBCPP___MEMORY_COMPRESSED_PAIR_H 172