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
40_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
41
42  using std::size_t;
43  using std::ptrdiff_t;
44
45  /**
46   *  @brief  An allocator that uses global new, as per [20.4].
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  template<typename _Tp>
53    class new_allocator
54    {
55    public:
56      typedef size_t     size_type;
57      typedef ptrdiff_t  difference_type;
58      typedef _Tp*       pointer;
59      typedef const _Tp* const_pointer;
60      typedef _Tp&       reference;
61      typedef const _Tp& const_reference;
62      typedef _Tp        value_type;
63
64      template<typename _Tp1>
65        struct rebind
66        { typedef new_allocator<_Tp1> other; };
67
68      new_allocator() throw() { }
69
70      new_allocator(const new_allocator&) throw() { }
71
72      template<typename _Tp1>
73        new_allocator(const new_allocator<_Tp1>&) throw() { }
74
75      ~new_allocator() throw() { }
76
77      pointer
78      address(reference __x) const { return &__x; }
79
80      const_pointer
81      address(const_reference __x) const { return &__x; }
82
83      // NB: __n is permitted to be 0.  The C++ standard says nothing
84      // about what the return value is when __n == 0.
85      pointer
86      allocate(size_type __n, const void* = 0)
87      {
88	if (__builtin_expect(__n > this->max_size(), false))
89	  std::__throw_bad_alloc();
90
91	return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
92      }
93
94      // __p is not permitted to be a null pointer.
95      void
96      deallocate(pointer __p, size_type)
97      { ::operator delete(__p); }
98
99      size_type
100      max_size() const throw()
101      { return size_t(-1) / sizeof(_Tp); }
102
103      // _GLIBCXX_RESOLVE_LIB_DEFECTS
104      // 402. wrong new expression in [some_] allocator::construct
105      void
106      construct(pointer __p, const _Tp& __val)
107      { ::new(__p) _Tp(__val); }
108
109      void
110      destroy(pointer __p) { __p->~_Tp(); }
111    };
112
113  template<typename _Tp>
114    inline bool
115    operator==(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
116    { return true; }
117
118  template<typename _Tp>
119    inline bool
120    operator!=(const new_allocator<_Tp>&, const new_allocator<_Tp>&)
121    { return false; }
122
123_GLIBCXX_END_NAMESPACE
124
125#endif
126