libstdc++-v3/include/bits/stl_construct.h

   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
  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