1 // Uses-allocator Construction -*- C++ -*- 2 3 // Copyright (C) 2010-2013 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 #if __cplusplus < 201103L 29 # include <bits/c++0x_warning.h> 30 #else 31 32 #include <type_traits> 33 34 namespace 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
