Line data    Source code

       1             : // Allocator that wraps operator new -*- C++ -*-
       2             : 
       3             : // Copyright (C) 2001-2021 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 ext/new_allocator.h
      26             :  *  This file is a GNU extension to the Standard C++ Library.
      27             :  */
      28             : 
      29             : #ifndef _NEW_ALLOCATOR_H
      30             : #define _NEW_ALLOCATOR_H 1
      31             : 
      32             : #include <bits/c++config.h>
      33             : #include <new>
      34             : #include <bits/functexcept.h>
      35             : #include <bits/move.h>
      36             : #if __cplusplus >= 201103L
      37             : #include <type_traits>
      38             : #endif
      39             : 
      40             : namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
      41             : {
      42             : _GLIBCXX_BEGIN_NAMESPACE_VERSION
      43             : 
      44             :   /**
      45             :    *  @brief  An allocator that uses global new, as per C++03 [20.4.1].
      46             :    *  @ingroup allocators
      47             :    *
      48             :    *  This is precisely the allocator defined in the C++ Standard.
      49             :    *    - all allocation calls operator new
      50             :    *    - all deallocation calls operator delete
      51             :    *
      52             :    *  @tparam  _Tp  Type of allocated object.
      53             :    */
      54             :   template<typename _Tp>
      55             :     class new_allocator
      56             :     {
      57             :     public:
      58             :       typedef _Tp        value_type;
      59             :       typedef std::size_t     size_type;
      60             :       typedef std::ptrdiff_t  difference_type;
      61             : #if __cplusplus <= 201703L
      62             :       typedef _Tp*       pointer;
      63             :       typedef const _Tp* const_pointer;
      64             :       typedef _Tp&       reference;
      65             :       typedef const _Tp& const_reference;
      66             : 
      67             :       template<typename _Tp1>
      68             :         struct rebind
      69             :         { typedef new_allocator<_Tp1> other; };
      70             : #endif
      71             : 
      72             : #if __cplusplus >= 201103L
      73             :       // _GLIBCXX_RESOLVE_LIB_DEFECTS
      74             :       // 2103. propagate_on_container_move_assignment
      75             :       typedef std::true_type propagate_on_container_move_assignment;
      76             : #endif
      77             : 
      78             :       _GLIBCXX20_CONSTEXPR
      79     2428631 :       new_allocator() _GLIBCXX_USE_NOEXCEPT { }
      80             : 
      81             :       _GLIBCXX20_CONSTEXPR
      82     1789420 :       new_allocator(const new_allocator&) _GLIBCXX_USE_NOEXCEPT { }
      83             : 
      84             :       template<typename _Tp1>
      85             :         _GLIBCXX20_CONSTEXPR
      86             :         new_allocator(const new_allocator<_Tp1>&) _GLIBCXX_USE_NOEXCEPT { }
      87             : 
      88             : #if __cplusplus <= 201703L
      89     8381144 :       ~new_allocator() _GLIBCXX_USE_NOEXCEPT { }
      90             : 
      91             :       pointer
      92             :       address(reference __x) const _GLIBCXX_NOEXCEPT
      93             :       { return std::__addressof(__x); }
      94             : 
      95             :       const_pointer
      96             :       address(const_reference __x) const _GLIBCXX_NOEXCEPT
      97             :       { return std::__addressof(__x); }
      98             : #endif
      99             : 
     100             :       // NB: __n is permitted to be 0.  The C++ standard says nothing
     101             :       // about what the return value is when __n == 0.
     102             :       _GLIBCXX_NODISCARD _Tp*
     103     6674560 :       allocate(size_type __n, const void* = static_cast<const void*>(0))
     104             :       {
     105             : #if __cplusplus >= 201103L
     106             :          // _GLIBCXX_RESOLVE_LIB_DEFECTS
     107             :          // 3308. std::allocator<void>().allocate(n)
     108             :          static_assert(sizeof(_Tp) != 0, "cannot allocate incomplete types");
     109             : #endif
     110             : 
     111     6674560 :         if (__builtin_expect(__n > this->_M_max_size(), false))
     112             :           {
     113             :             // _GLIBCXX_RESOLVE_LIB_DEFECTS
     114             :             // 3190. allocator::allocate sometimes returns too little storage
     115           0 :             if (__n > (std::size_t(-1) / sizeof(_Tp)))
     116           0 :               std::__throw_bad_array_new_length();
     117           0 :             std::__throw_bad_alloc();
     118             :           }
     119             : 
     120             : #if __cpp_aligned_new
     121             :         if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
     122             :           {
     123             :             std::align_val_t __al = std::align_val_t(alignof(_Tp));
     124             :             return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), __al));
     125             :           }
     126             : #endif
     127     6674634 :         return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
     128             :       }
     129             : 
     130             :       // __p is not permitted to be a null pointer.
     131             :       void
     132     3867137 :       deallocate(_Tp* __p, size_type __t __attribute__ ((__unused__)))
     133             :       {
     134             : #if __cpp_aligned_new
     135             :         if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
     136             :           {
     137             :             ::operator delete(__p,
     138             : # if __cpp_sized_deallocation
     139             :                               __t * sizeof(_Tp),
     140             : # endif
     141             :                               std::align_val_t(alignof(_Tp)));
     142             :             return;
     143             :           }
     144             : #endif
     145     3867137 :         ::operator delete(__p
     146             : #if __cpp_sized_deallocation
     147             :                           , __t * sizeof(_Tp)
     148             : #endif
     149             :                          );
     150             :       }
     151             : 
     152             : #if __cplusplus <= 201703L
     153             :       size_type
     154    19472779 :       max_size() const _GLIBCXX_USE_NOEXCEPT
     155    19472779 :       { return _M_max_size(); }
     156             : 
     157             : #if __cplusplus >= 201103L
     158             :       template<typename _Up, typename... _Args>
     159             :         void
     160    33143087 :         construct(_Up* __p, _Args&&... __args)
     161             :         noexcept(std::is_nothrow_constructible<_Up, _Args...>::value)
     162    33168471 :         { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
     163             : 
     164             :       template<typename _Up>
     165             :         void
     166    29373205 :         destroy(_Up* __p)
     167             :         noexcept(std::is_nothrow_destructible<_Up>::value)
     168    29373205 :         { __p->~_Up(); }
     169             : #else
     170             :       // _GLIBCXX_RESOLVE_LIB_DEFECTS
     171             :       // 402. wrong new expression in [some_] allocator::construct
     172             :       void
     173             :       construct(pointer __p, const _Tp& __val)
     174             :       { ::new((void *)__p) _Tp(__val); }
     175             : 
     176             :       void
     177             :       destroy(pointer __p) { __p->~_Tp(); }
     178             : #endif
     179             : #endif // ! C++20
     180             : 
     181             :       template<typename _Up>
     182             :         friend _GLIBCXX20_CONSTEXPR bool
     183             :         operator==(const new_allocator&, const new_allocator<_Up>&)
     184             :         _GLIBCXX_NOTHROW
     185             :         { return true; }
     186             : 
     187             : #if __cpp_impl_three_way_comparison < 201907L
     188             :       template<typename _Up>
     189             :         friend _GLIBCXX20_CONSTEXPR bool
     190             :         operator!=(const new_allocator&, const new_allocator<_Up>&)
     191             :         _GLIBCXX_NOTHROW
     192             :         { return false; }
     193             : #endif
     194             : 
     195             :     private:
     196             :       _GLIBCXX_CONSTEXPR size_type
     197    26147170 :       _M_max_size() const _GLIBCXX_USE_NOEXCEPT
     198             :       {
     199             : #if __PTRDIFF_MAX__ < __SIZE_MAX__
     200    26147170 :         return std::size_t(__PTRDIFF_MAX__) / sizeof(_Tp);
     201             : #else
     202             :         return std::size_t(-1) / sizeof(_Tp);
     203             : #endif
     204             :       }
     205             :     };
     206             : 
     207             : _GLIBCXX_END_NAMESPACE_VERSION
     208             : } // namespace
     209             : 
     210             : #endif