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 /** @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
  40 namespace __gnu_cxx
  41 {
  42   /**
  43    *  @brief  An allocator that uses global new, as per [20.4].
  44    *
  45    *  This is precisely the allocator defined in the C++ Standard.
  46    *    - all allocation calls operator new
  47    *    - all deallocation calls operator delete
  48    */
  49   template<typename _Tp>
  50     class new_allocator
  51     {
  52     public:
  53       typedef size_t     size_type;
  54       typedef ptrdiff_t  difference_type;
  55       typedef _Tp*       pointer;
  56       typedef const _Tp* const_pointer;
  57       typedef _Tp&       reference;
  58       typedef const _Tp& const_reference;
  59       typedef _Tp        value_type;
  60
  61       template<typename _Tp1>
  62         struct rebind
  63         { typedef new_allocator<_Tp1> other; };
  64
  65       new_allocator() throw() { }
  66
  67       new_allocator(const new_allocator&) throw() { }
  68
  69       template<typename _Tp1>
  70         new_allocator(const new_allocator<_Tp1>&) throw() { }
  71
  72       ~new_allocator() throw() { }
  73
  74       pointer
  75       address(reference __x) const { return &__x; }
  76
  77       const_pointer
  78       address(const_reference __x) const { return &__x; }
  79
  80       // NB: __n is permitted to be 0.  The C++ standard says nothing
  81       // about what the return value is when __n == 0.
  82       pointer
  83       allocate(size_type __n, const void* = 0)
  84       {
  85         if (__builtin_expect(__n > this->max_size(), false))
  86           std::__throw_bad_alloc();
  87
  88         return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
  89       }
  90
  91       // __p is not permitted to be a null pointer.
  92       void
  93       deallocate(pointer __p, size_type)
  94       { ::operator delete(__p); }
  95
  96       size_type
  97       max_size() const throw()
  98       { return size_t(-1) / sizeof(_Tp); }
  99
 100       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 101       // 402. wrong new expression in [some_] allocator::construct
 102       void
 103       construct(pointer __p, const _Tp& __val)
 104       { ::new(__p) _Tp(__val); }
 105
 106       void
 107       destroy(pointer __p) { __p->~_Tp(); }
 108     };
 109
 110   template<typename _Tp>
 111     inline bool
 112     operator==(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
 113     { return true; }
 114
 115   template<typename _Tp>
 116     inline bool
 117     operator!=(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
 118     { return false; }
 119 } // namespace __gnu_cxx
 120
 121 #endif