// Allocators -*- C++ -*- // Copyright (C) 2001-2020 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /* * Copyright (c) 1996-1997 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Silicon Graphics makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. */ /** @file bits/allocator.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{memory} */ #ifndef _ALLOCATOR_H #define _ALLOCATOR_H 1 #include <bits/c++allocator.h> // Define the base class to std::allocator. #include <bits/memoryfwd.h> #if __cplusplus >= 201103L #include <type_traits> #endif #define __cpp_lib_incomplete_container_elements 201505 namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION /** * @addtogroup allocators * @{ */ /// allocator<void> specialization. template<> class allocator<void> { public: typedef void value_type; typedef size_t size_type; typedef ptrdiff_t difference_type; #if __cplusplus <= 201703L typedef void* pointer; typedef const void* const_pointer; template<typename _Tp1> struct rebind { typedef allocator<_Tp1> other; }; #else allocator() = default; template<typename _Up> constexpr allocator(const allocator<_Up>&) { } #endif // ! C++20 #if __cplusplus >= 201103L && __cplusplus <= 201703L // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2103. std::allocator propagate_on_container_move_assignment typedef true_type propagate_on_container_move_assignment; typedef true_type is_always_equal; template<typename _Up, typename... _Args> void construct(_Up* __p, _Args&&... __args) noexcept(std::is_nothrow_constructible<_Up, _Args...>::value) { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } template<typename _Up> void destroy(_Up* __p) noexcept(std::is_nothrow_destructible<_Up>::value) { __p->~_Up(); } #endif // C++11 to C++17 }; /** * @brief The @a standard allocator, as per [20.4]. * * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator * for further details. * * @tparam _Tp Type of allocated object. */ template<typename _Tp> class allocator : public __allocator_base<_Tp> { public: typedef _Tp value_type; typedef size_t size_type; typedef ptrdiff_t difference_type; #if __cplusplus <= 201703L typedef _Tp* pointer; typedef const _Tp* const_pointer; typedef _Tp& reference; typedef const _Tp& const_reference; template<typename _Tp1> struct rebind { typedef allocator<_Tp1> other; }; #endif #if __cplusplus >= 201103L // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2103. std::allocator propagate_on_container_move_assignment typedef true_type propagate_on_container_move_assignment; typedef true_type is_always_equal; #endif // _GLIBCXX_RESOLVE_LIB_DEFECTS // 3035. std::allocator's constructors should be constexpr _GLIBCXX20_CONSTEXPR allocator() _GLIBCXX_NOTHROW { } _GLIBCXX20_CONSTEXPR allocator(const allocator& __a) _GLIBCXX_NOTHROW : __allocator_base<_Tp>(__a) { } #if __cplusplus >= 201103L // Avoid implicit deprecation. allocator& operator=(const allocator&) = default; #endif template<typename _Tp1> _GLIBCXX20_CONSTEXPR allocator(const allocator<_Tp1>&) _GLIBCXX_NOTHROW { } #if __cpp_constexpr_dynamic_alloc constexpr #endif ~allocator() _GLIBCXX_NOTHROW { } #if __cplusplus > 201703L [[nodiscard,__gnu__::__always_inline__]] constexpr _Tp* allocate(size_t __n) { #ifdef __cpp_lib_is_constant_evaluated if (std::is_constant_evaluated()) return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp))); #endif return __allocator_base<_Tp>::allocate(__n, 0); } [[__gnu__::__always_inline__]] constexpr void deallocate(_Tp* __p, size_t __n) { #ifdef __cpp_lib_is_constant_evaluated if (std::is_constant_evaluated()) { ::operator delete(__p); return; } #endif __allocator_base<_Tp>::deallocate(__p, __n); } #endif // C++20 friend _GLIBCXX20_CONSTEXPR bool operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW { return true; } #if __cpp_impl_three_way_comparison < 201907L friend _GLIBCXX20_CONSTEXPR bool operator!=(const allocator&, const allocator&) _GLIBCXX_NOTHROW { return false; } #endif // Inherit everything else. }; template<typename _T1, typename _T2> inline _GLIBCXX20_CONSTEXPR bool operator==(const allocator<_T1>&, const allocator<_T2>&) _GLIBCXX_NOTHROW { return true; } #if __cpp_impl_three_way_comparison < 201907L template<typename _T1, typename _T2> inline _GLIBCXX20_CONSTEXPR bool operator!=(const allocator<_T1>&, const allocator<_T2>&) _GLIBCXX_NOTHROW { return false; } #endif // Invalid allocator<cv T> partial specializations. // allocator_traits::rebind_alloc can be used to form a valid allocator type. template<typename _Tp> class allocator<const _Tp> { public: typedef _Tp value_type; template<typename _Up> allocator(const allocator<_Up>&) { } }; template<typename _Tp> class allocator<volatile _Tp> { public: typedef _Tp value_type; template<typename _Up> allocator(const allocator<_Up>&) { } }; template<typename _Tp> class allocator<const volatile _Tp> { public: typedef _Tp value_type; template<typename _Up> allocator(const allocator<_Up>&) { } }; /// @} group allocator // Inhibit implicit instantiations for required instantiations, // which are defined via explicit instantiations elsewhere. #if _GLIBCXX_EXTERN_TEMPLATE extern template class allocator<char>; extern template class allocator<wchar_t>; #endif // Undefine. #undef __allocator_base // To implement Option 3 of DR 431. template<typename _Alloc, bool = __is_empty(_Alloc)> struct __alloc_swap { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } }; template<typename _Alloc> struct __alloc_swap<_Alloc, false> { static void _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT { // Precondition: swappable allocators. if (__one != __two) swap(__one, __two); } }; // Optimize for stateless allocators. template<typename _Alloc, bool = __is_empty(_Alloc)> struct __alloc_neq { static bool _S_do_it(const _Alloc&, const _Alloc&) { return false; } }; template<typename _Alloc> struct __alloc_neq<_Alloc, false> { static bool _S_do_it(const _Alloc& __one, const _Alloc& __two) { return __one != __two; } }; #if __cplusplus >= 201103L template<typename _Tp, bool = __or_<is_copy_constructible<typename _Tp::value_type>, is_nothrow_move_constructible<typename _Tp::value_type>>::value> struct __shrink_to_fit_aux { static bool _S_do_it(_Tp&) noexcept { return false; } }; template<typename _Tp> struct __shrink_to_fit_aux<_Tp, true> { static bool _S_do_it(_Tp& __c) noexcept { #if __cpp_exceptions try { _Tp(__make_move_if_noexcept_iterator(__c.begin()), __make_move_if_noexcept_iterator(__c.end()), __c.get_allocator()).swap(__c); return true; } catch(...) { return false; } #else return false; #endif } }; #endif _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #endif