xref: /llvm-project/libcxx/include/__cxx03/__memory/construct_at.h (revision ce7771902dc50d900de639d499a60486b83f70e0)
1e78f53d1SNikolas Klauser // -*- C++ -*-
2e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===//
3e78f53d1SNikolas Klauser //
4e78f53d1SNikolas Klauser // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5e78f53d1SNikolas Klauser // See https://llvm.org/LICENSE.txt for license information.
6e78f53d1SNikolas Klauser // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7e78f53d1SNikolas Klauser //
8e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===//
9e78f53d1SNikolas Klauser 
10*ce777190SNikolas Klauser #ifndef _LIBCPP___CXX03___MEMORY_CONSTRUCT_AT_H
11*ce777190SNikolas Klauser #define _LIBCPP___CXX03___MEMORY_CONSTRUCT_AT_H
12e78f53d1SNikolas Klauser 
1373fbae83SNikolas Klauser #include <__cxx03/__assert>
1473fbae83SNikolas Klauser #include <__cxx03/__config>
1573fbae83SNikolas Klauser #include <__cxx03/__iterator/access.h>
1673fbae83SNikolas Klauser #include <__cxx03/__memory/addressof.h>
1773fbae83SNikolas Klauser #include <__cxx03/__memory/voidify.h>
1873fbae83SNikolas Klauser #include <__cxx03/__type_traits/enable_if.h>
1973fbae83SNikolas Klauser #include <__cxx03/__type_traits/is_array.h>
2073fbae83SNikolas Klauser #include <__cxx03/__utility/declval.h>
2173fbae83SNikolas Klauser #include <__cxx03/__utility/forward.h>
2273fbae83SNikolas Klauser #include <__cxx03/__utility/move.h>
2373fbae83SNikolas Klauser #include <__cxx03/new>
24e78f53d1SNikolas Klauser 
25e78f53d1SNikolas Klauser #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26e78f53d1SNikolas Klauser #  pragma GCC system_header
27e78f53d1SNikolas Klauser #endif
28e78f53d1SNikolas Klauser 
29e78f53d1SNikolas Klauser _LIBCPP_PUSH_MACROS
3073fbae83SNikolas Klauser #include <__cxx03/__undef_macros>
31e78f53d1SNikolas Klauser 
32e78f53d1SNikolas Klauser _LIBCPP_BEGIN_NAMESPACE_STD
33e78f53d1SNikolas Klauser 
34e78f53d1SNikolas Klauser // construct_at
35e78f53d1SNikolas Klauser 
36e78f53d1SNikolas Klauser #if _LIBCPP_STD_VER >= 20
37e78f53d1SNikolas Klauser 
38e78f53d1SNikolas Klauser template <class _Tp, class... _Args, class = decltype(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))>
39e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI constexpr _Tp* construct_at(_Tp* __location, _Args&&... __args) {
40e78f53d1SNikolas Klauser   _LIBCPP_ASSERT_NON_NULL(__location != nullptr, "null pointer given to construct_at");
41e78f53d1SNikolas Klauser   return ::new (std::__voidify(*__location)) _Tp(std::forward<_Args>(__args)...);
42e78f53d1SNikolas Klauser }
43e78f53d1SNikolas Klauser 
44e78f53d1SNikolas Klauser #endif
45e78f53d1SNikolas Klauser 
46e78f53d1SNikolas Klauser template <class _Tp, class... _Args, class = decltype(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))>
47e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp* __construct_at(_Tp* __location, _Args&&... __args) {
48e78f53d1SNikolas Klauser #if _LIBCPP_STD_VER >= 20
49e78f53d1SNikolas Klauser   return std::construct_at(__location, std::forward<_Args>(__args)...);
50e78f53d1SNikolas Klauser #else
51e78f53d1SNikolas Klauser   return _LIBCPP_ASSERT_NON_NULL(__location != nullptr, "null pointer given to construct_at"),
52e78f53d1SNikolas Klauser          ::new (std::__voidify(*__location)) _Tp(std::forward<_Args>(__args)...);
53e78f53d1SNikolas Klauser #endif
54e78f53d1SNikolas Klauser }
55e78f53d1SNikolas Klauser 
56e78f53d1SNikolas Klauser // destroy_at
57e78f53d1SNikolas Klauser 
58e78f53d1SNikolas Klauser // The internal functions are available regardless of the language version (with the exception of the `__destroy_at`
59e78f53d1SNikolas Klauser // taking an array).
60e78f53d1SNikolas Klauser 
61e78f53d1SNikolas Klauser template <class _ForwardIterator>
62e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator __destroy(_ForwardIterator, _ForwardIterator);
63e78f53d1SNikolas Klauser 
64e78f53d1SNikolas Klauser template <class _Tp, __enable_if_t<!is_array<_Tp>::value, int> = 0>
65e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy_at(_Tp* __loc) {
66e78f53d1SNikolas Klauser   _LIBCPP_ASSERT_NON_NULL(__loc != nullptr, "null pointer given to destroy_at");
67e78f53d1SNikolas Klauser   __loc->~_Tp();
68e78f53d1SNikolas Klauser }
69e78f53d1SNikolas Klauser 
70e78f53d1SNikolas Klauser #if _LIBCPP_STD_VER >= 20
71e78f53d1SNikolas Klauser template <class _Tp, __enable_if_t<is_array<_Tp>::value, int> = 0>
72e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy_at(_Tp* __loc) {
73e78f53d1SNikolas Klauser   _LIBCPP_ASSERT_NON_NULL(__loc != nullptr, "null pointer given to destroy_at");
74e78f53d1SNikolas Klauser   std::__destroy(std::begin(*__loc), std::end(*__loc));
75e78f53d1SNikolas Klauser }
76e78f53d1SNikolas Klauser #endif
77e78f53d1SNikolas Klauser 
78e78f53d1SNikolas Klauser template <class _ForwardIterator>
79e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
80e78f53d1SNikolas Klauser __destroy(_ForwardIterator __first, _ForwardIterator __last) {
81e78f53d1SNikolas Klauser   for (; __first != __last; ++__first)
82e78f53d1SNikolas Klauser     std::__destroy_at(std::addressof(*__first));
83e78f53d1SNikolas Klauser   return __first;
84e78f53d1SNikolas Klauser }
85e78f53d1SNikolas Klauser 
86e78f53d1SNikolas Klauser template <class _BidirectionalIterator>
87e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _BidirectionalIterator
88e78f53d1SNikolas Klauser __reverse_destroy(_BidirectionalIterator __first, _BidirectionalIterator __last) {
89e78f53d1SNikolas Klauser   while (__last != __first) {
90e78f53d1SNikolas Klauser     --__last;
91e78f53d1SNikolas Klauser     std::__destroy_at(std::addressof(*__last));
92e78f53d1SNikolas Klauser   }
93e78f53d1SNikolas Klauser   return __last;
94e78f53d1SNikolas Klauser }
95e78f53d1SNikolas Klauser 
96e78f53d1SNikolas Klauser #if _LIBCPP_STD_VER >= 17
97e78f53d1SNikolas Klauser 
98e78f53d1SNikolas Klauser template <class _Tp, enable_if_t<!is_array_v<_Tp>, int> = 0>
99e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void destroy_at(_Tp* __loc) {
100e78f53d1SNikolas Klauser   std::__destroy_at(__loc);
101e78f53d1SNikolas Klauser }
102e78f53d1SNikolas Klauser 
103e78f53d1SNikolas Klauser #  if _LIBCPP_STD_VER >= 20
104e78f53d1SNikolas Klauser template <class _Tp, enable_if_t<is_array_v<_Tp>, int> = 0>
105e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void destroy_at(_Tp* __loc) {
106e78f53d1SNikolas Klauser   std::__destroy_at(__loc);
107e78f53d1SNikolas Klauser }
108e78f53d1SNikolas Klauser #  endif
109e78f53d1SNikolas Klauser 
110e78f53d1SNikolas Klauser template <class _ForwardIterator>
111e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void destroy(_ForwardIterator __first, _ForwardIterator __last) {
112e78f53d1SNikolas Klauser   (void)std::__destroy(std::move(__first), std::move(__last));
113e78f53d1SNikolas Klauser }
114e78f53d1SNikolas Klauser 
115e78f53d1SNikolas Klauser template <class _ForwardIterator, class _Size>
116e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator destroy_n(_ForwardIterator __first, _Size __n) {
117e78f53d1SNikolas Klauser   for (; __n > 0; (void)++__first, --__n)
118e78f53d1SNikolas Klauser     std::__destroy_at(std::addressof(*__first));
119e78f53d1SNikolas Klauser   return __first;
120e78f53d1SNikolas Klauser }
121e78f53d1SNikolas Klauser 
122e78f53d1SNikolas Klauser #endif // _LIBCPP_STD_VER >= 17
123e78f53d1SNikolas Klauser 
124e78f53d1SNikolas Klauser _LIBCPP_END_NAMESPACE_STD
125e78f53d1SNikolas Klauser 
126e78f53d1SNikolas Klauser _LIBCPP_POP_MACROS
127e78f53d1SNikolas Klauser 
128*ce777190SNikolas Klauser #endif // _LIBCPP___CXX03___MEMORY_CONSTRUCT_AT_H
129