1// array allocator -*- C++ -*-
2
3// Copyright (C) 2004, 2005, 2006 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/array_allocator.h
31 *  This file is a GNU extension to the Standard C++ Library.
32 */
33
34#ifndef _ARRAY_ALLOCATOR_H
35#define _ARRAY_ALLOCATOR_H 1
36
37#include <cstddef>
38#include <new>
39#include <bits/functexcept.h>
40#include <tr1/array>
41
42_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
43
44 using std::size_t;
45 using std::ptrdiff_t;
46
47  /// @brief  Base class.
48 template<typename _Tp>
49    class array_allocator_base
50    {
51    public:
52      typedef size_t     	size_type;
53      typedef ptrdiff_t  	difference_type;
54      typedef _Tp*       	pointer;
55      typedef const _Tp* 	const_pointer;
56      typedef _Tp&       	reference;
57      typedef const _Tp&	const_reference;
58      typedef _Tp        	value_type;
59
60      pointer
61      address(reference __x) const { return &__x; }
62
63      const_pointer
64      address(const_reference __x) const { return &__x; }
65
66      void
67      deallocate(pointer, size_type)
68      {
69	// Does nothing.
70      }
71
72      size_type
73      max_size() const throw()
74      { return size_t(-1) / sizeof(_Tp); }
75
76      // _GLIBCXX_RESOLVE_LIB_DEFECTS
77      // 402. wrong new expression in [some_] allocator::construct
78      void
79      construct(pointer __p, const _Tp& __val)
80      { ::new(__p) value_type(__val); }
81
82      void
83      destroy(pointer __p) { __p->~_Tp(); }
84    };
85
86  /**
87   *  @brief  An allocator that uses previously allocated memory.
88   *  This memory can be externally, globally, or otherwise allocated.
89   */
90  template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
91    class array_allocator : public array_allocator_base<_Tp>
92    {
93    public:
94      typedef size_t     	size_type;
95      typedef ptrdiff_t  	difference_type;
96      typedef _Tp*       	pointer;
97      typedef const _Tp* 	const_pointer;
98      typedef _Tp&       	reference;
99      typedef const _Tp& 	const_reference;
100      typedef _Tp        	value_type;
101      typedef _Array		array_type;
102
103    private:
104      array_type* 	_M_array;
105      size_type 	_M_used;
106
107    public:
108     template<typename _Tp1, typename _Array1 = _Array>
109        struct rebind
110        { typedef array_allocator<_Tp1, _Array1> other; };
111
112      array_allocator(array_type* __array = NULL) throw()
113      : _M_array(__array), _M_used(size_type()) { }
114
115      array_allocator(const array_allocator& __o)  throw()
116      : _M_array(__o._M_array), _M_used(__o._M_used) { }
117
118      template<typename _Tp1, typename _Array1>
119        array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
120	: _M_array(NULL), _M_used(size_type()) { }
121
122      ~array_allocator() throw() { }
123
124      pointer
125      allocate(size_type __n, const void* = 0)
126      {
127	if (_M_array == 0 || _M_used + __n > _M_array->size())
128	  std::__throw_bad_alloc();
129	pointer __ret = _M_array->begin() + _M_used;
130	_M_used += __n;
131	return __ret;
132      }
133    };
134
135  template<typename _Tp, typename _Array>
136    inline bool
137    operator==(const array_allocator<_Tp, _Array>&,
138	       const array_allocator<_Tp, _Array>&)
139    { return true; }
140
141  template<typename _Tp, typename _Array>
142    inline bool
143    operator!=(const array_allocator<_Tp, _Array>&,
144	       const array_allocator<_Tp, _Array>&)
145    { return false; }
146
147_GLIBCXX_END_NAMESPACE
148
149#endif
150