Line data    Source code

       1             : // Allocator that wraps operator new -*- C++ -*-
       2             : 
       3             : // Copyright (C) 2001-2022 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             : /** @file bits/new_allocator.h
      26             :  *  This is an internal header file, included by other library headers.
      27             :  *  Do not attempt to use it directly. @headername{memory}
      28             :  */
      29             : 
      30             : #ifndef _STD_NEW_ALLOCATOR_H
      31             : #define _STD_NEW_ALLOCATOR_H 1
      32             : 
      33             : #include <bits/c++config.h>
      34             : #include <new>
      35             : #include <bits/functexcept.h>
      36             : #include <bits/move.h>
      37             : #if __cplusplus >= 201103L
      38             : #include <type_traits>
      39             : #endif
      40             : 
      41             : namespace std _GLIBCXX_VISIBILITY(default)
      42             : {
      43             : _GLIBCXX_BEGIN_NAMESPACE_VERSION
      44             : 
      45             :   /**
      46             :    *  @brief  An allocator that uses global new, as per C++03 [20.4.1].
      47             :    *  @ingroup allocators
      48             :    *
      49             :    *  This is precisely the allocator defined in the C++ Standard.
      50             :    *    - all allocation calls operator new
      51             :    *    - all deallocation calls operator delete
      52             :    *
      53             :    *  @tparam  _Tp  Type of allocated object.
      54             :    */
      55             :   template<typename _Tp>
      56             :     class __new_allocator
      57             :     {
      58             :     public:
      59             :       typedef _Tp        value_type;
      60             :       typedef std::size_t     size_type;
      61             :       typedef std::ptrdiff_t  difference_type;
      62             : #if __cplusplus <= 201703L
      63             :       typedef _Tp*       pointer;
      64             :       typedef const _Tp* const_pointer;
      65             :       typedef _Tp&       reference;
      66             :       typedef const _Tp& const_reference;
      67             : 
      68             :       template<typename _Tp1>
      69             :         struct rebind
      70             :         { typedef __new_allocator<_Tp1> other; };
      71             : #endif
      72             : 
      73             : #if __cplusplus >= 201103L
      74             :       // _GLIBCXX_RESOLVE_LIB_DEFECTS
      75             :       // 2103. propagate_on_container_move_assignment
      76             :       typedef std::true_type propagate_on_container_move_assignment;
      77             : #endif
      78             : 
      79             :       _GLIBCXX20_CONSTEXPR
      80       11561 :       __new_allocator() _GLIBCXX_USE_NOEXCEPT { }
      81             : 
      82             :       _GLIBCXX20_CONSTEXPR
      83        8825 :       __new_allocator(const __new_allocator&) _GLIBCXX_USE_NOEXCEPT { }
      84             : 
      85             :       template<typename _Tp1>
      86             :         _GLIBCXX20_CONSTEXPR
      87             :         __new_allocator(const __new_allocator<_Tp1>&) _GLIBCXX_USE_NOEXCEPT { }
      88             : 
      89             : #if __cplusplus <= 201703L
      90       70002 :       ~__new_allocator() _GLIBCXX_USE_NOEXCEPT { }
      91             : 
      92             :       pointer
      93             :       address(reference __x) const _GLIBCXX_NOEXCEPT
      94             :       { return std::__addressof(__x); }
      95             : 
      96             :       const_pointer
      97             :       address(const_reference __x) const _GLIBCXX_NOEXCEPT
      98             :       { return std::__addressof(__x); }
      99             : #endif
     100             : 
     101             : #if __has_builtin(__builtin_operator_new) >= 201802L
     102             : # define _GLIBCXX_OPERATOR_NEW __builtin_operator_new
     103             : # define _GLIBCXX_OPERATOR_DELETE __builtin_operator_delete
     104             : #else
     105             : # define _GLIBCXX_OPERATOR_NEW ::operator new
     106             : # define _GLIBCXX_OPERATOR_DELETE ::operator delete
     107             : #endif
     108             : 
     109             :       // NB: __n is permitted to be 0.  The C++ standard says nothing
     110             :       // about what the return value is when __n == 0.
     111             :       _GLIBCXX_NODISCARD _Tp*
     112      142204 :       allocate(size_type __n, const void* = static_cast<const void*>(0))
     113             :       {
     114             : #if __cplusplus >= 201103L
     115             :         // _GLIBCXX_RESOLVE_LIB_DEFECTS
     116             :         // 3308. std::allocator<void>().allocate(n)
     117             :         static_assert(sizeof(_Tp) != 0, "cannot allocate incomplete types");
     118             : #endif
     119             : 
     120      142204 :         if (__builtin_expect(__n > this->_M_max_size(), false))
     121             :           {
     122             :             // _GLIBCXX_RESOLVE_LIB_DEFECTS
     123             :             // 3190. allocator::allocate sometimes returns too little storage
     124           0 :             if (__n > (std::size_t(-1) / sizeof(_Tp)))
     125           0 :               std::__throw_bad_array_new_length();
     126           0 :             std::__throw_bad_alloc();
     127             :           }
     128             : 
     129             : #if __cpp_aligned_new
     130             :         if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
     131             :           {
     132             :             std::align_val_t __al = std::align_val_t(alignof(_Tp));
     133             :             return static_cast<_Tp*>(_GLIBCXX_OPERATOR_NEW(__n * sizeof(_Tp),
     134             :                                                            __al));
     135             :           }
     136             : #endif
     137      142204 :         return static_cast<_Tp*>(_GLIBCXX_OPERATOR_NEW(__n * sizeof(_Tp)));
     138             :       }
     139             : 
     140             :       // __p is not permitted to be a null pointer.
     141             :       void
     142      147954 :       deallocate(_Tp* __p, size_type __n __attribute__ ((__unused__)))
     143             :       {
     144             : #if __cpp_sized_deallocation
     145             : # define _GLIBCXX_SIZED_DEALLOC(p, n) (p), (n) * sizeof(_Tp)
     146             : #else
     147             : # define _GLIBCXX_SIZED_DEALLOC(p, n) (p)
     148             : #endif
     149             : 
     150             : #if __cpp_aligned_new
     151             :         if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
     152             :           {
     153             :             _GLIBCXX_OPERATOR_DELETE(_GLIBCXX_SIZED_DEALLOC(__p, __n),
     154             :                                      std::align_val_t(alignof(_Tp)));
     155             :             return;
     156             :           }
     157             : #endif
     158      147954 :         _GLIBCXX_OPERATOR_DELETE(_GLIBCXX_SIZED_DEALLOC(__p, __n));
     159             :       }
     160             : 
     161             : #undef _GLIBCXX_SIZED_DEALLOC
     162             : #undef _GLIBCXX_OPERATOR_DELETE
     163             : #undef _GLIBCXX_OPERATOR_NEW
     164             : 
     165             : #if __cplusplus <= 201703L
     166             :       size_type
     167             :       max_size() const _GLIBCXX_USE_NOEXCEPT
     168             :       { return _M_max_size(); }
     169             : 
     170             : #if __cplusplus >= 201103L
     171             :       template<typename _Up, typename... _Args>
     172             :         void
     173      142204 :         construct(_Up* __p, _Args&&... __args)
     174             :         noexcept(std::is_nothrow_constructible<_Up, _Args...>::value)
     175      142204 :         { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
     176             : 
     177             :       template<typename _Up>
     178             :         void
     179       26276 :         destroy(_Up* __p)
     180             :         noexcept(std::is_nothrow_destructible<_Up>::value)
     181      142131 :         { __p->~_Up(); }
     182             : #else
     183             :       // _GLIBCXX_RESOLVE_LIB_DEFECTS
     184             :       // 402. wrong new expression in [some_] allocator::construct
     185             :       void
     186             :       construct(pointer __p, const _Tp& __val)
     187             :       { ::new((void *)__p) _Tp(__val); }
     188             : 
     189             :       void
     190             :       destroy(pointer __p) { __p->~_Tp(); }
     191             : #endif
     192             : #endif // ! C++20
     193             : 
     194             :       template<typename _Up>
     195             :         friend _GLIBCXX20_CONSTEXPR bool
     196             :         operator==(const __new_allocator&, const __new_allocator<_Up>&)
     197             :         _GLIBCXX_NOTHROW
     198             :         { return true; }
     199             : 
     200             : #if __cpp_impl_three_way_comparison < 201907L
     201             :       template<typename _Up>
     202             :         friend _GLIBCXX20_CONSTEXPR bool
     203             :         operator!=(const __new_allocator&, const __new_allocator<_Up>&)
     204             :         _GLIBCXX_NOTHROW
     205             :         { return false; }
     206             : #endif
     207             : 
     208             :     private:
     209             :       _GLIBCXX_CONSTEXPR size_type
     210             :       _M_max_size() const _GLIBCXX_USE_NOEXCEPT
     211             :       {
     212             : #if __PTRDIFF_MAX__ < __SIZE_MAX__
     213             :         return std::size_t(__PTRDIFF_MAX__) / sizeof(_Tp);
     214             : #else
     215             :         return std::size_t(-1) / sizeof(_Tp);
     216             : #endif
     217             :       }
     218             :     };
     219             : 
     220             : _GLIBCXX_END_NAMESPACE_VERSION
     221             : } // namespace
     222             : 
     223             : #endif