1// <extptr_allocator.h> -*- C++ -*- 2 3// Copyright (C) 2008, 2009, 2010 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/** 26 * @file ext/extptr_allocator.h 27 * This file is a GNU extension to the Standard C++ Library. 28 * 29 * @author Bob Walters 30 * 31 * An example allocator which uses an alternative pointer type from 32 * bits/pointer.h. Supports test cases which confirm container support 33 * for alternative pointers. 34 */ 35 36#ifndef _EXTPTR_ALLOCATOR_H 37#define _EXTPTR_ALLOCATOR_H 1 38 39#include <memory> 40#include <limits> 41#include <ext/pointer.h> 42 43namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 44{ 45_GLIBCXX_BEGIN_NAMESPACE_VERSION 46 47 /** 48 * @brief An example allocator which uses a non-standard pointer type. 49 * @ingroup allocators 50 * 51 * This allocator specifies that containers use a 'relative pointer' as it's 52 * pointer type. (See ext/pointer.h) Memory allocation in this example 53 * is still performed using std::allocator. 54 */ 55 template<typename _Tp> 56 class _ExtPtr_allocator 57 { 58 public: 59 typedef std::size_t size_type; 60 typedef std::ptrdiff_t difference_type; 61 62 // Note the non-standard pointer types. 63 typedef _Pointer_adapter<_Relative_pointer_impl<_Tp> > pointer; 64 typedef _Pointer_adapter<_Relative_pointer_impl<const _Tp> > 65 const_pointer; 66 67 typedef _Tp& reference; 68 typedef const _Tp& const_reference; 69 typedef _Tp value_type; 70 71 template<typename _Up> 72 struct rebind 73 { typedef _ExtPtr_allocator<_Up> other; }; 74 75 _ExtPtr_allocator() throw() 76 : _M_real_alloc() { } 77 78 _ExtPtr_allocator(const _ExtPtr_allocator &__rarg) throw() 79 : _M_real_alloc(__rarg._M_real_alloc) { } 80 81 template<typename _Up> 82 _ExtPtr_allocator(const _ExtPtr_allocator<_Up>& __rarg) throw() 83 : _M_real_alloc(__rarg._M_getUnderlyingImp()) { } 84 85 ~_ExtPtr_allocator() throw() 86 { } 87 88 pointer address(reference __x) const 89 { return std::__addressof(__x); } 90 91 const_pointer address(const_reference __x) const 92 { return std::__addressof(__x); } 93 94 pointer allocate(size_type __n, void* __hint = 0) 95 { return _M_real_alloc.allocate(__n,__hint); } 96 97 void deallocate(pointer __p, size_type __n) 98 { _M_real_alloc.deallocate(__p.get(), __n); } 99 100 size_type max_size() const throw() 101 { return std::numeric_limits<size_type>::max() / sizeof(_Tp); } 102 103 void construct(pointer __p, const _Tp& __val) 104 { ::new(__p.get()) _Tp(__val); } 105 106#ifdef __GXX_EXPERIMENTAL_CXX0X__ 107 template<typename... _Args> 108 void 109 construct(pointer __p, _Args&&... __args) 110 { ::new(__p.get()) _Tp(std::forward<_Args>(__args)...); } 111#endif 112 113 void destroy(pointer __p) 114 { __p->~_Tp(); } 115 116 template<typename _Up> 117 inline bool 118 operator==(const _ExtPtr_allocator<_Up>& __rarg) 119 { return _M_real_alloc == __rarg._M_getUnderlyingImp(); } 120 121 inline bool 122 operator==(const _ExtPtr_allocator& __rarg) 123 { return _M_real_alloc == __rarg._M_real_alloc; } 124 125 template<typename _Up> 126 inline bool 127 operator!=(const _ExtPtr_allocator<_Up>& __rarg) 128 { return _M_real_alloc != __rarg._M_getUnderlyingImp(); } 129 130 inline bool 131 operator!=(const _ExtPtr_allocator& __rarg) 132 { return _M_real_alloc != __rarg._M_real_alloc; } 133 134 template<typename _Up> 135 inline friend void 136 swap(_ExtPtr_allocator<_Up>&, _ExtPtr_allocator<_Up>&); 137 138 // A method specific to this implementation. 139 const std::allocator<_Tp>& 140 _M_getUnderlyingImp() const 141 { return _M_real_alloc; } 142 143 private: 144 std::allocator<_Tp> _M_real_alloc; 145 }; 146 147 // _ExtPtr_allocator<void> specialization. 148 template<> 149 class _ExtPtr_allocator<void> 150 { 151 public: 152 typedef std::size_t size_type; 153 typedef std::ptrdiff_t difference_type; 154 typedef void value_type; 155 156 // Note the non-standard pointer types 157 typedef _Pointer_adapter<_Relative_pointer_impl<void> > pointer; 158 typedef _Pointer_adapter<_Relative_pointer_impl<const void> > 159 const_pointer; 160 161 template<typename _Up> 162 struct rebind 163 { typedef _ExtPtr_allocator<_Up> other; }; 164 165 private: 166 std::allocator<void> _M_real_alloc; 167 }; 168 169 template<typename _Tp> 170 inline void 171 swap(_ExtPtr_allocator<_Tp>& __larg, _ExtPtr_allocator<_Tp>& __rarg) 172 { 173 std::allocator<_Tp> __tmp( __rarg._M_real_alloc ); 174 __rarg._M_real_alloc = __larg._M_real_alloc; 175 __larg._M_real_alloc = __tmp; 176 } 177 178_GLIBCXX_END_NAMESPACE_VERSION 179} // namespace 180 181#endif /* _EXTPTR_ALLOCATOR_H */ 182