libstdc++-v3/include/ext/new_allocator.h

   1 // Allocator that wraps operator new -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009, 2010
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /** @file ext/new_allocator.h
  27  *  This file is a GNU extension to the Standard C++ Library.
  28  */
  29
  30 #ifndef _NEW_ALLOCATOR_H
  31 #define _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
  38 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  39
  40   using std::size_t;
  41   using std::ptrdiff_t;
  42
  43   /**
  44    *  @brief  An allocator that uses global new, as per [20.4].
  45    *  @ingroup allocators
  46    *
  47    *  This is precisely the allocator defined in the C++ Standard.
  48    *    - all allocation calls operator new
  49    *    - all deallocation calls operator delete
  50    */
  51   template<typename _Tp>
  52     class new_allocator
  53     {
  54     public:
  55       typedef size_t     size_type;
  56       typedef ptrdiff_t  difference_type;
  57       typedef _Tp*       pointer;
  58       typedef const _Tp* const_pointer;
  59       typedef _Tp&       reference;
  60       typedef const _Tp& const_reference;
  61       typedef _Tp        value_type;
  62
  63       template<typename _Tp1>
  64         struct rebind
  65         { typedef new_allocator<_Tp1> other; };
  66
  67       new_allocator() throw() { }
  68
  69       new_allocator(const new_allocator&) throw() { }
  70
  71       template<typename _Tp1>
  72         new_allocator(const new_allocator<_Tp1>&) throw() { }
  73
  74       ~new_allocator() throw() { }
  75
  76       pointer
  77       address(reference __x) const { return std::__addressof(__x); }
  78
  79       const_pointer
  80       address(const_reference __x) const { return std::__addressof(__x); }
  81
  82       // NB: __n is permitted to be 0.  The C++ standard says nothing
  83       // about what the return value is when __n == 0.
  84       pointer
  85       allocate(size_type __n, const void* = 0)
  86       {
  87         if (__n > this->max_size())
  88           std::__throw_bad_alloc();
  89
  90         return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
  91       }
  92
  93       // __p is not permitted to be a null pointer.
  94       void
  95       deallocate(pointer __p, size_type)
  96       { ::operator delete(__p); }
  97
  98       size_type
  99       max_size() const throw()
 100       { return size_t(-1) / sizeof(_Tp); }
 101
 102       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 103       // 402. wrong new expression in [some_] allocator::construct
 104       void
 105       construct(pointer __p, const _Tp& __val)
 106       { ::new((void *)__p) _Tp(__val); }
 107
 108 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 109       template<typename... _Args>
 110         void
 111         construct(pointer __p, _Args&&... __args)
 112         { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
 113 #endif
 114
 115       void
 116       destroy(pointer __p) { __p->~_Tp(); }
 117     };
 118
 119   template<typename _Tp>
 120     inline bool
 121     operator==(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
 122     { return true; }
 123
 124   template<typename _Tp>
 125     inline bool
 126     operator!=(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
 127     { return false; }
 128
 129 _GLIBCXX_END_NAMESPACE
 130
 131 #endif