1// Uses-allocator Construction -*- C++ -*-
2
3// Copyright (C) 2010, 2011 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 3, 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// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25#ifndef _USES_ALLOCATOR_H
26#define _USES_ALLOCATOR_H 1
27
28#ifndef __GXX_EXPERIMENTAL_CXX0X__
29# include <bits/c++0x_warning.h>
30#else
31
32#include <type_traits>
33
34namespace std _GLIBCXX_VISIBILITY(default)
35{
36_GLIBCXX_BEGIN_NAMESPACE_VERSION
37
38  /// [allocator.tag]
39  struct allocator_arg_t { };
40
41  constexpr allocator_arg_t allocator_arg = allocator_arg_t();
42
43_GLIBCXX_HAS_NESTED_TYPE(allocator_type)
44
45  template<typename _Tp, typename _Alloc,
46	   bool = __has_allocator_type<_Tp>::value>
47    struct __uses_allocator_helper
48    : public false_type { };
49
50  template<typename _Tp, typename _Alloc>
51    struct __uses_allocator_helper<_Tp, _Alloc, true>
52    : public integral_constant<bool, is_convertible<_Alloc,
53				     typename _Tp::allocator_type>::value>
54    { };
55
56  /// [allocator.uses.trait]
57  template<typename _Tp, typename _Alloc>
58    struct uses_allocator
59    : public integral_constant<bool,
60			       __uses_allocator_helper<_Tp, _Alloc>::value>
61    { };
62
63  template<typename _Tp, typename _Alloc, typename... _Args>
64    struct __uses_allocator_arg
65    : is_constructible<_Tp, _Alloc, _Args...>
66    { static_assert( uses_allocator<_Tp, _Alloc>::value, "uses allocator" ); };
67
68  struct __uses_alloc_base { };
69  struct __uses_alloc0 : __uses_alloc_base
70  { struct _Anything { _Anything(...) { } } _M_a; };
71  template<typename _Alloc>
72    struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; };
73  template<typename _Alloc>
74    struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; };
75
76  template<bool, typename _Alloc, typename... _Args>
77    struct __uses_alloc;
78
79  template<typename _Tp, typename _Alloc, typename... _Args>
80    struct __uses_alloc<true, _Tp, _Alloc, _Args...>
81    : conditional<
82        is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value,
83        __uses_alloc1<_Alloc>,
84       	__uses_alloc2<_Alloc>>::type
85    { };
86
87  template<typename _Tp, typename _Alloc, typename... _Args>
88    struct __uses_alloc<false, _Tp, _Alloc, _Args...>
89    : __uses_alloc0 { };
90
91  template<typename _Tp, typename _Alloc, typename... _Args>
92    struct __uses_alloc_impl
93    : __uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp,  _Alloc, _Args...>
94    { };
95
96  template<typename _Tp, typename _Alloc, typename... _Args>
97    __uses_alloc_impl<_Tp, _Alloc, _Args...>
98    __use_alloc(const _Alloc& __a)
99    {
100      __uses_alloc_impl<_Tp, _Alloc, _Args...> __ret;
101      __ret._M_a = &__a;
102      return __ret;
103    }
104
105_GLIBCXX_END_NAMESPACE_VERSION
106} // namespace std
107
108#endif
109#endif
110