1// array allocator -*- C++ -*-
2
3// Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009
4// Free Software Foundation, Inc.
5//
6// This file is part of the GNU ISO C++ Library.  This library is free
7// software; you can redistribute it and/or modify it under the
8// terms of the GNU General Public License as published by the
9// Free Software Foundation; either version 3, or (at your option)
10// any later version.
11
12// This library is distributed in the hope that it will be useful,
13// but WITHOUT ANY WARRANTY; without even the implied warranty of
14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15// GNU General Public License for more details.
16
17// Under Section 7 of GPL version 3, you are granted additional
18// permissions described in the GCC Runtime Library Exception, version
19// 3.1, as published by the Free Software Foundation.
20
21// You should have received a copy of the GNU General Public License and
22// a copy of the GCC Runtime Library Exception along with this program;
23// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24// <http://www.gnu.org/licenses/>.
25
26/** @file ext/array_allocator.h
27 *  This file is a GNU extension to the Standard C++ Library.
28 */
29
30#ifndef _ARRAY_ALLOCATOR_H
31#define _ARRAY_ALLOCATOR_H 1
32
33#include <cstddef>
34#include <new>
35#include <bits/functexcept.h>
36#include <tr1/array>
37#include <bits/move.h>
38
39_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
40
41 using std::size_t;
42 using std::ptrdiff_t;
43
44  /// Base class.
45 template<typename _Tp>
46    class array_allocator_base
47    {
48    public:
49      typedef size_t     	size_type;
50      typedef ptrdiff_t  	difference_type;
51      typedef _Tp*       	pointer;
52      typedef const _Tp* 	const_pointer;
53      typedef _Tp&       	reference;
54      typedef const _Tp&	const_reference;
55      typedef _Tp        	value_type;
56
57      pointer
58      address(reference __x) const { return &__x; }
59
60      const_pointer
61      address(const_reference __x) const { return &__x; }
62
63      void
64      deallocate(pointer, size_type)
65      {
66	// Does nothing.
67      }
68
69      size_type
70      max_size() const throw()
71      { return size_t(-1) / sizeof(_Tp); }
72
73      // _GLIBCXX_RESOLVE_LIB_DEFECTS
74      // 402. wrong new expression in [some_] allocator::construct
75      void
76      construct(pointer __p, const _Tp& __val)
77      { ::new((void *)__p) value_type(__val); }
78
79#ifdef __GXX_EXPERIMENTAL_CXX0X__
80      template<typename... _Args>
81        void
82        construct(pointer __p, _Args&&... __args)
83	{ ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
84#endif
85
86      void
87      destroy(pointer __p) { __p->~_Tp(); }
88    };
89
90  /**
91   *  @brief  An allocator that uses previously allocated memory.
92   *  This memory can be externally, globally, or otherwise allocated.
93   *  @ingroup allocators
94   */
95  template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
96    class array_allocator : public array_allocator_base<_Tp>
97    {
98    public:
99      typedef size_t     	size_type;
100      typedef ptrdiff_t  	difference_type;
101      typedef _Tp*       	pointer;
102      typedef const _Tp* 	const_pointer;
103      typedef _Tp&       	reference;
104      typedef const _Tp& 	const_reference;
105      typedef _Tp        	value_type;
106      typedef _Array		array_type;
107
108    private:
109      array_type* 	_M_array;
110      size_type 	_M_used;
111
112    public:
113     template<typename _Tp1, typename _Array1 = _Array>
114        struct rebind
115        { typedef array_allocator<_Tp1, _Array1> other; };
116
117      array_allocator(array_type* __array = NULL) throw()
118      : _M_array(__array), _M_used(size_type()) { }
119
120      array_allocator(const array_allocator& __o)  throw()
121      : _M_array(__o._M_array), _M_used(__o._M_used) { }
122
123      template<typename _Tp1, typename _Array1>
124        array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
125	: _M_array(NULL), _M_used(size_type()) { }
126
127      ~array_allocator() throw() { }
128
129      pointer
130      allocate(size_type __n, const void* = 0)
131      {
132	if (_M_array == 0 || _M_used + __n > _M_array->size())
133	  std::__throw_bad_alloc();
134	pointer __ret = _M_array->begin() + _M_used;
135	_M_used += __n;
136	return __ret;
137      }
138    };
139
140  template<typename _Tp, typename _Array>
141    inline bool
142    operator==(const array_allocator<_Tp, _Array>&,
143	       const array_allocator<_Tp, _Array>&)
144    { return true; }
145
146  template<typename _Tp, typename _Array>
147    inline bool
148    operator!=(const array_allocator<_Tp, _Array>&,
149	       const array_allocator<_Tp, _Array>&)
150    { return false; }
151
152_GLIBCXX_END_NAMESPACE
153
154#endif
155