libstdc++
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00001 // Allocators -*- C++ -*- 00002 00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 00004 // Free Software Foundation, Inc. 00005 // 00006 // This file is part of the GNU ISO C++ Library. This library is free 00007 // software; you can redistribute it and/or modify it under the 00008 // terms of the GNU General Public License as published by the 00009 // Free Software Foundation; either version 3, or (at your option) 00010 // any later version. 00011 00012 // This library is distributed in the hope that it will be useful, 00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 // GNU General Public License for more details. 00016 00017 // Under Section 7 of GPL version 3, you are granted additional 00018 // permissions described in the GCC Runtime Library Exception, version 00019 // 3.1, as published by the Free Software Foundation. 00020 00021 // You should have received a copy of the GNU General Public License and 00022 // a copy of the GCC Runtime Library Exception along with this program; 00023 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00024 // <http://www.gnu.org/licenses/>. 00025 00026 /* 00027 * Copyright (c) 1996-1997 00028 * Silicon Graphics Computer Systems, Inc. 00029 * 00030 * Permission to use, copy, modify, distribute and sell this software 00031 * and its documentation for any purpose is hereby granted without fee, 00032 * provided that the above copyright notice appear in all copies and 00033 * that both that copyright notice and this permission notice appear 00034 * in supporting documentation. Silicon Graphics makes no 00035 * representations about the suitability of this software for any 00036 * purpose. It is provided "as is" without express or implied warranty. 00037 */ 00038 00039 /** @file bits/allocator.h 00040 * This is an internal header file, included by other library headers. 00041 * Do not attempt to use it directly. @headername{memory} 00042 */ 00043 00044 #ifndef _ALLOCATOR_H 00045 #define _ALLOCATOR_H 1 00046 00047 // Define the base class to std::allocator. 00048 #include <bits/c++allocator.h> 00049 00050 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00051 #include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE 00052 #endif 00053 00054 namespace std _GLIBCXX_VISIBILITY(default) 00055 { 00056 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00057 00058 /** 00059 * @defgroup allocators Allocators 00060 * @ingroup memory 00061 * 00062 * Classes encapsulating memory operations. 00063 */ 00064 00065 template<typename _Tp> 00066 class allocator; 00067 00068 /// allocator<void> specialization. 00069 template<> 00070 class allocator<void> 00071 { 00072 public: 00073 typedef size_t size_type; 00074 typedef ptrdiff_t difference_type; 00075 typedef void* pointer; 00076 typedef const void* const_pointer; 00077 typedef void value_type; 00078 00079 template<typename _Tp1> 00080 struct rebind 00081 { typedef allocator<_Tp1> other; }; 00082 }; 00083 00084 /** 00085 * @brief The @a standard allocator, as per [20.4]. 00086 * @ingroup allocators 00087 * 00088 * Further details: 00089 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html 00090 */ 00091 template<typename _Tp> 00092 class allocator: public __glibcxx_base_allocator<_Tp> 00093 { 00094 public: 00095 typedef size_t size_type; 00096 typedef ptrdiff_t difference_type; 00097 typedef _Tp* pointer; 00098 typedef const _Tp* const_pointer; 00099 typedef _Tp& reference; 00100 typedef const _Tp& const_reference; 00101 typedef _Tp value_type; 00102 00103 template<typename _Tp1> 00104 struct rebind 00105 { typedef allocator<_Tp1> other; }; 00106 00107 allocator() throw() { } 00108 00109 allocator(const allocator& __a) throw() 00110 : __glibcxx_base_allocator<_Tp>(__a) { } 00111 00112 template<typename _Tp1> 00113 allocator(const allocator<_Tp1>&) throw() { } 00114 00115 ~allocator() throw() { } 00116 00117 // Inherit everything else. 00118 }; 00119 00120 template<typename _T1, typename _T2> 00121 inline bool 00122 operator==(const allocator<_T1>&, const allocator<_T2>&) 00123 { return true; } 00124 00125 template<typename _Tp> 00126 inline bool 00127 operator==(const allocator<_Tp>&, const allocator<_Tp>&) 00128 { return true; } 00129 00130 template<typename _T1, typename _T2> 00131 inline bool 00132 operator!=(const allocator<_T1>&, const allocator<_T2>&) 00133 { return false; } 00134 00135 template<typename _Tp> 00136 inline bool 00137 operator!=(const allocator<_Tp>&, const allocator<_Tp>&) 00138 { return false; } 00139 00140 // Inhibit implicit instantiations for required instantiations, 00141 // which are defined via explicit instantiations elsewhere. 00142 // NB: This syntax is a GNU extension. 00143 #if _GLIBCXX_EXTERN_TEMPLATE 00144 extern template class allocator<char>; 00145 extern template class allocator<wchar_t>; 00146 #endif 00147 00148 // Undefine. 00149 #undef __glibcxx_base_allocator 00150 00151 // To implement Option 3 of DR 431. 00152 template<typename _Alloc, bool = __is_empty(_Alloc)> 00153 struct __alloc_swap 00154 { static void _S_do_it(_Alloc&, _Alloc&) { } }; 00155 00156 template<typename _Alloc> 00157 struct __alloc_swap<_Alloc, false> 00158 { 00159 static void 00160 _S_do_it(_Alloc& __one, _Alloc& __two) 00161 { 00162 // Precondition: swappable allocators. 00163 if (__one != __two) 00164 swap(__one, __two); 00165 } 00166 }; 00167 00168 // Optimize for stateless allocators. 00169 template<typename _Alloc, bool = __is_empty(_Alloc)> 00170 struct __alloc_neq 00171 { 00172 static bool 00173 _S_do_it(const _Alloc&, const _Alloc&) 00174 { return false; } 00175 }; 00176 00177 template<typename _Alloc> 00178 struct __alloc_neq<_Alloc, false> 00179 { 00180 static bool 00181 _S_do_it(const _Alloc& __one, const _Alloc& __two) 00182 { return __one != __two; } 00183 }; 00184 00185 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00186 // A very basic implementation for now. In general we have to wait for 00187 // the availability of the infrastructure described in N2983: we should 00188 // try when either T has a move constructor which cannot throw or T is 00189 // CopyContructible. 00190 // NB: This code doesn't properly belong here, we should find a more 00191 // suited place common to std::vector and std::deque. 00192 template<typename _Tp, 00193 bool = __has_trivial_copy(typename _Tp::value_type)> 00194 struct __shrink_to_fit 00195 { static void _S_do_it(_Tp&) { } }; 00196 00197 template<typename _Tp> 00198 struct __shrink_to_fit<_Tp, true> 00199 { 00200 static void 00201 _S_do_it(_Tp& __v) 00202 { 00203 __try 00204 { _Tp(__v).swap(__v); } 00205 __catch(...) { } 00206 } 00207 }; 00208 00209 00210 /// [allocator.tag] 00211 struct allocator_arg_t { }; 00212 00213 constexpr allocator_arg_t allocator_arg = allocator_arg_t(); 00214 00215 _GLIBCXX_HAS_NESTED_TYPE(allocator_type) 00216 00217 template<typename _Tp, typename _Alloc, 00218 bool = __has_allocator_type<_Tp>::value> 00219 struct __uses_allocator_helper 00220 : public false_type { }; 00221 00222 template<typename _Tp, typename _Alloc> 00223 struct __uses_allocator_helper<_Tp, _Alloc, true> 00224 : public integral_constant<bool, is_convertible<_Alloc, 00225 typename _Tp::allocator_type>::value> 00226 { }; 00227 00228 /// [allocator.uses.trait] 00229 template<typename _Tp, typename _Alloc> 00230 struct uses_allocator 00231 : public integral_constant<bool, 00232 __uses_allocator_helper<_Tp, _Alloc>::value> 00233 { }; 00234 00235 #endif 00236 00237 _GLIBCXX_END_NAMESPACE_VERSION 00238 } // namespace 00239 00240 #endif