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

   1 // Allocator that wraps operator new -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  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 #ifndef _NEW_ALLOCATOR_H
  31 #define _NEW_ALLOCATOR_H 1
  32
  33 #include <new>
  34 #include <bits/functexcept.h>
  35
  36 namespace __gnu_cxx
  37 {
  38   /**
  39    *  @brief  An allocator that uses global new, as per [20.4].
  40    *
  41    *  This is precisely the allocator defined in the C++ Standard.
  42    *    - all allocation calls operator new
  43    *    - all deallocation calls operator delete
  44    *
  45    *  (See @link Allocators allocators info @endlink for more.)
  46    */
  47   template<typename _Tp>
  48     class new_allocator
  49     {
  50     public:
  51       typedef size_t     size_type;
  52       typedef ptrdiff_t  difference_type;
  53       typedef _Tp*       pointer;
  54       typedef const _Tp* const_pointer;
  55       typedef _Tp&       reference;
  56       typedef const _Tp& const_reference;
  57       typedef _Tp        value_type;
  58
  59       template<typename _Tp1>
  60         struct rebind
  61         { typedef new_allocator<_Tp1> other; };
  62
  63       new_allocator() throw() { }
  64
  65       new_allocator(const new_allocator&) throw() { }
  66
  67       template<typename _Tp1>
  68         new_allocator(const new_allocator<_Tp1>&) throw() { }
  69
  70       ~new_allocator() throw() { }
  71
  72       pointer
  73       address(reference __x) const { return &__x; }
  74
  75       const_pointer
  76       address(const_reference __x) const { return &__x; }
  77
  78       // NB: __n is permitted to be 0.  The C++ standard says nothing
  79       // about what the return value is when __n == 0.
  80       pointer
  81       allocate(size_type __n, const void* = 0)
  82       {
  83         if (__builtin_expect(__n > this->max_size(), false))
  84           std::__throw_bad_alloc();
  85
  86         return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
  87       }
  88
  89       // __p is not permitted to be a null pointer.
  90       void
  91       deallocate(pointer __p, size_type)
  92       { ::operator delete(__p); }
  93
  94       size_type
  95       max_size() const throw()
  96       { return size_t(-1) / sizeof(_Tp); }
  97
  98       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  99       // 402. wrong new expression in [some_] allocator::construct
 100       void
 101       construct(pointer __p, const _Tp& __val)
 102       { ::new(__p) _Tp(__val); }
 103
 104       void
 105       destroy(pointer __p) { __p->~_Tp(); }
 106     };
 107
 108   template<typename _Tp>
 109     inline bool
 110     operator==(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
 111     { return true; }
 112
 113   template<typename _Tp>
 114     inline bool
 115     operator!=(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
 116     { return false; }
 117 } // namespace __gnu_cxx
 118
 119 #endif