1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H 11 #define _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H 12 13 #include <__config> 14 #include <__memory/uses_allocator.h> 15 #include <__type_traits/integral_constant.h> 16 #include <__type_traits/is_constructible.h> 17 #include <__type_traits/remove_cvref.h> 18 #include <__utility/forward.h> 19 20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21 # pragma GCC system_header 22 #endif 23 24 _LIBCPP_BEGIN_NAMESPACE_STD 25 26 struct _LIBCPP_TEMPLATE_VIS allocator_arg_t { explicit allocator_arg_t() = default; }; 27 28 #if _LIBCPP_STD_VER >= 17 29 inline constexpr allocator_arg_t allocator_arg = allocator_arg_t(); 30 #elif !defined(_LIBCPP_CXX03_LANG) 31 constexpr allocator_arg_t allocator_arg = allocator_arg_t(); 32 #endif 33 34 #ifndef _LIBCPP_CXX03_LANG 35 36 // allocator construction 37 38 template <class _Tp, class _Alloc, class ..._Args> 39 struct __uses_alloc_ctor_imp 40 { 41 typedef _LIBCPP_NODEBUG __remove_cvref_t<_Alloc> _RawAlloc; 42 static const bool __ua = uses_allocator<_Tp, _RawAlloc>::value; 43 static const bool __ic = 44 is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value; 45 static const int value = __ua ? 2 - __ic : 0; 46 }; 47 48 template <class _Tp, class _Alloc, class ..._Args> 49 struct __uses_alloc_ctor 50 : integral_constant<int, __uses_alloc_ctor_imp<_Tp, _Alloc, _Args...>::value> 51 {}; 52 53 template <class _Tp, class _Allocator, class... _Args> 54 inline _LIBCPP_INLINE_VISIBILITY 55 void __user_alloc_construct_impl (integral_constant<int, 0>, _Tp *__storage, const _Allocator &, _Args &&... __args ) 56 { 57 new (__storage) _Tp (_VSTD::forward<_Args>(__args)...); 58 } 59 60 // FIXME: This should have a version which takes a non-const alloc. 61 template <class _Tp, class _Allocator, class... _Args> 62 inline _LIBCPP_INLINE_VISIBILITY 63 void __user_alloc_construct_impl (integral_constant<int, 1>, _Tp *__storage, const _Allocator &__a, _Args &&... __args ) 64 { 65 new (__storage) _Tp (allocator_arg, __a, _VSTD::forward<_Args>(__args)...); 66 } 67 68 // FIXME: This should have a version which takes a non-const alloc. 69 template <class _Tp, class _Allocator, class... _Args> 70 inline _LIBCPP_INLINE_VISIBILITY 71 void __user_alloc_construct_impl (integral_constant<int, 2>, _Tp *__storage, const _Allocator &__a, _Args &&... __args ) 72 { 73 new (__storage) _Tp (_VSTD::forward<_Args>(__args)..., __a); 74 } 75 76 #endif // _LIBCPP_CXX03_LANG 77 78 _LIBCPP_END_NAMESPACE_STD 79 80 #endif // _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H 81