1// Allocator that wraps "C" malloc -*- 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, 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/malloc_allocator.h
31 *  This file is a GNU extension to the Standard C++ Library.
32 */
33
34#ifndef _MALLOC_ALLOCATOR_H
35#define _MALLOC_ALLOCATOR_H 1
36
37#include <cstdlib>
38#include <new>
39#include <bits/functexcept.h>
40
41namespace __gnu_cxx
42{
43  /**
44   *  @brief  An allocator that uses malloc.
45   *
46   *  This is precisely the allocator defined in the C++ Standard.
47   *    - all allocation calls malloc
48   *    - all deallocation calls free
49   */
50  template<typename _Tp>
51    class malloc_allocator
52    {
53    public:
54      typedef size_t     size_type;
55      typedef ptrdiff_t  difference_type;
56      typedef _Tp*       pointer;
57      typedef const _Tp* const_pointer;
58      typedef _Tp&       reference;
59      typedef const _Tp& const_reference;
60      typedef _Tp        value_type;
61
62      template<typename _Tp1>
63        struct rebind
64        { typedef malloc_allocator<_Tp1> other; };
65
66      malloc_allocator() throw() { }
67
68      malloc_allocator(const malloc_allocator&) throw() { }
69
70      template<typename _Tp1>
71        malloc_allocator(const malloc_allocator<_Tp1>&) throw() { }
72
73      ~malloc_allocator() throw() { }
74
75      pointer
76      address(reference __x) const { return &__x; }
77
78      const_pointer
79      address(const_reference __x) const { return &__x; }
80
81      // NB: __n is permitted to be 0.  The C++ standard says nothing
82      // about what the return value is when __n == 0.
83      pointer
84      allocate(size_type __n, const void* = 0)
85      {
86	if (__builtin_expect(__n > this->max_size(), false))
87	  std::__throw_bad_alloc();
88
89	pointer __ret = static_cast<_Tp*>(malloc(__n * sizeof(_Tp)));
90	if (!__ret)
91	  std::__throw_bad_alloc();
92	return __ret;
93      }
94
95      // __p is not permitted to be a null pointer.
96      void
97      deallocate(pointer __p, size_type)
98      { free(static_cast<void*>(__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(__p) value_type(__val); }
109
110      void
111      destroy(pointer __p) { __p->~_Tp(); }
112    };
113
114  template<typename _Tp>
115    inline bool
116    operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
117    { return true; }
118
119  template<typename _Tp>
120    inline bool
121    operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
122    { return false; }
123} // namespace __gnu_cxx
124
125#endif
126