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

   1 // Allocator that wraps operator new -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /** @file ext/new_allocator.h
  31  *  This file is a GNU extension to the Standard C++ Library.
  32  */
  33
  34 #ifndef _NEW_ALLOCATOR_H
  35 #define _NEW_ALLOCATOR_H 1
  36
  37 #include <new>
  38 #include <bits/functexcept.h>
  39 #include <bits/stl_move.h>
  40
  41 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  42
  43   using std::size_t;
  44   using std::ptrdiff_t;
  45
  46   /**
  47    *  @brief  An allocator that uses global new, as per [20.4].
  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   template<typename _Tp>
  54     class new_allocator
  55     {
  56     public:
  57       typedef size_t     size_type;
  58       typedef ptrdiff_t  difference_type;
  59       typedef _Tp*       pointer;
  60       typedef const _Tp* const_pointer;
  61       typedef _Tp&       reference;
  62       typedef const _Tp& const_reference;
  63       typedef _Tp        value_type;
  64
  65       template<typename _Tp1>
  66         struct rebind
  67         { typedef new_allocator<_Tp1> other; };
  68
  69       new_allocator() throw() { }
  70
  71       new_allocator(const new_allocator&) throw() { }
  72
  73       template<typename _Tp1>
  74         new_allocator(const new_allocator<_Tp1>&) throw() { }
  75
  76       ~new_allocator() throw() { }
  77
  78       pointer
  79       address(reference __x) const { return &__x; }
  80
  81       const_pointer
  82       address(const_reference __x) const { return &__x; }
  83
  84       // NB: __n is permitted to be 0.  The C++ standard says nothing
  85       // about what the return value is when __n == 0.
  86       pointer
  87       allocate(size_type __n, const void* = 0)
  88       {
  89         if (__builtin_expect(__n > this->max_size(), false))
  90           std::__throw_bad_alloc();
  91
  92         return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
  93       }
  94
  95       // __p is not permitted to be a null pointer.
  96       void
  97       deallocate(pointer __p, size_type)
  98       { ::operator delete(__p); }
  99
 100       size_type
 101       max_size() const throw()
 102       { return size_t(-1) / sizeof(_Tp); }
 103
 104       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 105       // 402. wrong new expression in [some_] allocator::construct
 106       void
 107       construct(pointer __p, const _Tp& __val)
 108       { ::new((void *)__p) _Tp(__val); }
 109
 110 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 111       template<typename... _Args>
 112         void
 113         construct(pointer __p, _Args&&... __args)
 114         { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
 115 #endif
 116
 117       void
 118       destroy(pointer __p) { __p->~_Tp(); }
 119     };
 120
 121   template<typename _Tp>
 122     inline bool
 123     operator==(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
 124     { return true; }
 125
 126   template<typename _Tp>
 127     inline bool
 128     operator!=(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
 129     { return false; }
 130
 131 _GLIBCXX_END_NAMESPACE
 132
 133 #endif