1 // nonstandard construct and destroy functions -*- C++ -*-
2 
3 // Copyright (C) 2001-2018 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /*
26  *
27  * Copyright (c) 1994
28  * Hewlett-Packard Company
29  *
30  * Permission to use, copy, modify, distribute and sell this software
31  * and its documentation for any purpose is hereby granted without fee,
32  * provided that the above copyright notice appear in all copies and
33  * that both that copyright notice and this permission notice appear
34  * in supporting documentation.  Hewlett-Packard Company makes no
35  * representations about the suitability of this software for any
36  * purpose.  It is provided "as is" without express or implied warranty.
37  *
38  *
39  * Copyright (c) 1996,1997
40  * Silicon Graphics Computer Systems, Inc.
41  *
42  * Permission to use, copy, modify, distribute and sell this software
43  * and its documentation for any purpose is hereby granted without fee,
44  * provided that the above copyright notice appear in all copies and
45  * that both that copyright notice and this permission notice appear
46  * in supporting documentation.  Silicon Graphics makes no
47  * representations about the suitability of this software for any
48  * purpose.  It is provided "as is" without express or implied warranty.
49  */
50 
51 /** @file bits/stl_construct.h
52  *  This is an internal header file, included by other library headers.
53  *  Do not attempt to use it directly. @headername{memory}
54  */
55 
56 #ifndef _STL_CONSTRUCT_H
57 #define _STL_CONSTRUCT_H 1
58 
59 #include <new>
60 #include <bits/move.h>
61 #include <ext/alloc_traits.h>
62 
_GLIBCXX_VISIBILITY(default)63 namespace std _GLIBCXX_VISIBILITY(default)
64 {
65 _GLIBCXX_BEGIN_NAMESPACE_VERSION
66 
67   /**
68    * Constructs an object in existing memory by invoking an allocated
69    * object's constructor with an initializer.
70    */
71 #if __cplusplus >= 201103L
72   template<typename _T1, typename... _Args>
73     inline void
74     _Construct(_T1* __p, _Args&&... __args)
75     { ::new(static_cast<void*>(__p)) _T1(std::forward<_Args>(__args)...); }
76 #else
77   template<typename _T1, typename _T2>
78     inline void
79     _Construct(_T1* __p, const _T2& __value)
80     {
81       // _GLIBCXX_RESOLVE_LIB_DEFECTS
82       // 402. wrong new expression in [some_]allocator::construct
83       ::new(static_cast<void*>(__p)) _T1(__value);
84     }
85 #endif
86 
87   template<typename _T1>
88     inline void
89     _Construct_novalue(_T1* __p)
90     { ::new(static_cast<void*>(__p)) _T1; }
91 
92   /**
93    * Destroy the object pointed to by a pointer type.
94    */
95   template<typename _Tp>
96     inline void
97     _Destroy(_Tp* __pointer)
98     { __pointer->~_Tp(); }
99 
100   template<bool>
101     struct _Destroy_aux
102     {
103       template<typename _ForwardIterator>
104         static void
105         __destroy(_ForwardIterator __first, _ForwardIterator __last)
106 	{
107 	  for (; __first != __last; ++__first)
108 	    std::_Destroy(std::__addressof(*__first));
109 	}
110     };
111 
112   template<>
113     struct _Destroy_aux<true>
114     {
115       template<typename _ForwardIterator>
116         static void
117         __destroy(_ForwardIterator, _ForwardIterator) { }
118     };
119 
120   /**
121    * Destroy a range of objects.  If the value_type of the object has
122    * a trivial destructor, the compiler should optimize all of this
123    * away, otherwise the objects' destructors must be invoked.
124    */
125   template<typename _ForwardIterator>
126     inline void
127     _Destroy(_ForwardIterator __first, _ForwardIterator __last)
128     {
129       typedef typename iterator_traits<_ForwardIterator>::value_type
130                        _Value_type;
131 #if __cplusplus >= 201103L
132       // A deleted destructor is trivial, this ensures we reject such types:
133       static_assert(is_destructible<_Value_type>::value,
134 		    "value type is destructible");
135 #endif
136       std::_Destroy_aux<__has_trivial_destructor(_Value_type)>::
137 	__destroy(__first, __last);
138     }
139 
140   template<bool>
141     struct _Destroy_n_aux
142     {
143       template<typename _ForwardIterator, typename _Size>
144         static _ForwardIterator
145         __destroy_n(_ForwardIterator __first, _Size __count)
146 	{
147 	  for (; __count > 0; (void)++__first, --__count)
148 	    std::_Destroy(std::__addressof(*__first));
149 	  return __first;
150 	}
151     };
152 
153   template<>
154     struct _Destroy_n_aux<true>
155     {
156       template<typename _ForwardIterator, typename _Size>
157         static _ForwardIterator
158         __destroy_n(_ForwardIterator __first, _Size __count)
159 	{
160 	  std::advance(__first, __count);
161 	  return __first;
162 	}
163     };
164 
165   /**
166    * Destroy a range of objects.  If the value_type of the object has
167    * a trivial destructor, the compiler should optimize all of this
168    * away, otherwise the objects' destructors must be invoked.
169    */
170   template<typename _ForwardIterator, typename _Size>
171     inline _ForwardIterator
172     _Destroy_n(_ForwardIterator __first, _Size __count)
173     {
174       typedef typename iterator_traits<_ForwardIterator>::value_type
175                        _Value_type;
176 #if __cplusplus >= 201103L
177       // A deleted destructor is trivial, this ensures we reject such types:
178       static_assert(is_destructible<_Value_type>::value,
179 		    "value type is destructible");
180 #endif
181       return std::_Destroy_n_aux<__has_trivial_destructor(_Value_type)>::
182 	__destroy_n(__first, __count);
183     }
184 
185   /**
186    * Destroy a range of objects using the supplied allocator.  For
187    * nondefault allocators we do not optimize away invocation of
188    * destroy() even if _Tp has a trivial destructor.
189    */
190 
191   template<typename _ForwardIterator, typename _Allocator>
192     void
193     _Destroy(_ForwardIterator __first, _ForwardIterator __last,
194 	     _Allocator& __alloc)
195     {
196       typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
197       for (; __first != __last; ++__first)
198 	__traits::destroy(__alloc, std::__addressof(*__first));
199     }
200 
201   template<typename _ForwardIterator, typename _Tp>
202     inline void
203     _Destroy(_ForwardIterator __first, _ForwardIterator __last,
204 	     allocator<_Tp>&)
205     {
206       _Destroy(__first, __last);
207     }
208 
209 #if __cplusplus > 201402L
210   template <typename _Tp>
211     inline void
212     destroy_at(_Tp* __location)
213     {
214       std::_Destroy(__location);
215     }
216 
217   template <typename _ForwardIterator>
218     inline void
219     destroy(_ForwardIterator __first, _ForwardIterator __last)
220     {
221       std::_Destroy(__first, __last);
222     }
223 
224   template <typename _ForwardIterator, typename _Size>
225     inline _ForwardIterator
226     destroy_n(_ForwardIterator __first, _Size __count)
227     {
228       return std::_Destroy_n(__first, __count);
229     }
230 #endif
231 
232 _GLIBCXX_END_NAMESPACE_VERSION
233 } // namespace std
234 
235 #endif /* _STL_CONSTRUCT_H */
236 
237