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// Allocator that wraps operator new -*- C++ -*- |
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// Copyright (C) 2001-2021 Free Software Foundation, Inc. |
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// |
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// This file is part of the GNU ISO C++ Library. This library is free |
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// software; you can redistribute it and/or modify it under the |
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// terms of the GNU General Public License as published by the |
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// Free Software Foundation; either version 3, or (at your option) |
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// any later version. |
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|
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// This library is distributed in the hope that it will be useful, |
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// but WITHOUT ANY WARRANTY; without even the implied warranty of |
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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// GNU General Public License for more details. |
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|
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// Under Section 7 of GPL version 3, you are granted additional |
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// permissions described in the GCC Runtime Library Exception, version |
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// 3.1, as published by the Free Software Foundation. |
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|
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// You should have received a copy of the GNU General Public License and |
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// a copy of the GCC Runtime Library Exception along with this program; |
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
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// <http://www.gnu.org/licenses/>. |
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|
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/** @file ext/new_allocator.h |
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* This file is a GNU extension to the Standard C++ Library. |
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*/ |
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|
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#ifndef _NEW_ALLOCATOR_H |
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#define _NEW_ALLOCATOR_H 1 |
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|
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#include <bits/c++config.h> |
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#include <new> |
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#include <bits/functexcept.h> |
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#include <bits/move.h> |
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#if __cplusplus >= 201103L |
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#include <type_traits> |
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#endif |
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|
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namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
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{ |
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_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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|
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/** |
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* @brief An allocator that uses global new, as per C++03 [20.4.1]. |
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* @ingroup allocators |
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* |
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* This is precisely the allocator defined in the C++ Standard. |
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* - all allocation calls operator new |
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* - all deallocation calls operator delete |
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* |
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* @tparam _Tp Type of allocated object. |
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*/ |
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template<typename _Tp> |
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class new_allocator |
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{ |
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public: |
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typedef _Tp value_type; |
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typedef std::size_t size_type; |
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typedef std::ptrdiff_t difference_type; |
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#if __cplusplus <= 201703L |
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typedef _Tp* pointer; |
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typedef const _Tp* const_pointer; |
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typedef _Tp& reference; |
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typedef const _Tp& const_reference; |
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|
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template<typename _Tp1> |
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struct rebind |
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{ typedef new_allocator<_Tp1> other; }; |
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#endif |
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|
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#if __cplusplus >= 201103L |
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// _GLIBCXX_RESOLVE_LIB_DEFECTS |
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// 2103. propagate_on_container_move_assignment |
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typedef std::true_type propagate_on_container_move_assignment; |
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#endif |
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|
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_GLIBCXX20_CONSTEXPR |
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new_allocator() _GLIBCXX_USE_NOEXCEPT { } |
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|
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_GLIBCXX20_CONSTEXPR |
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new_allocator(const new_allocator&) _GLIBCXX_USE_NOEXCEPT { } |
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|
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template<typename _Tp1> |
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_GLIBCXX20_CONSTEXPR |
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new_allocator(const new_allocator<_Tp1>&) _GLIBCXX_USE_NOEXCEPT { } |
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|
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#if __cplusplus <= 201703L |
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~new_allocator() _GLIBCXX_USE_NOEXCEPT { } |
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|
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pointer |
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address(reference __x) const _GLIBCXX_NOEXCEPT |
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{ return std::__addressof(__x); } |
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|
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const_pointer |
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address(const_reference __x) const _GLIBCXX_NOEXCEPT |
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{ return std::__addressof(__x); } |
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#endif |
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|
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// NB: __n is permitted to be 0. The C++ standard says nothing |
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// about what the return value is when __n == 0. |
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_GLIBCXX_NODISCARD _Tp* |
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allocate(size_type __n, const void* = static_cast<const void*>(0)) |
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{ |
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#if __cplusplus >= 201103L |
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// _GLIBCXX_RESOLVE_LIB_DEFECTS |
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// 3308. std::allocator<void>().allocate(n) |
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static_assert(sizeof(_Tp) != 0, "cannot allocate incomplete types"); |
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#endif |
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|
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if (__builtin_expect(__n > this->_M_max_size(), false)) |
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{ |
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// _GLIBCXX_RESOLVE_LIB_DEFECTS |
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// 3190. allocator::allocate sometimes returns too little storage |
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if (__n > (std::size_t(-1) / sizeof(_Tp))) |
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std::__throw_bad_array_new_length(); |
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std::__throw_bad_alloc(); |
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} |
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|
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#if __cpp_aligned_new |
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if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__) |
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{ |
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std::align_val_t __al = std::align_val_t(alignof(_Tp)); |
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return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), __al)); |
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} |
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#endif |
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return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp))); |
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} |
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|
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// __p is not permitted to be a null pointer. |
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void |
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deallocate(_Tp* __p, size_type __t __attribute__ ((__unused__))) |
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{ |
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#if __cpp_aligned_new |
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if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__) |
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{ |
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::operator delete(__p, |
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# if __cpp_sized_deallocation |
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__t * sizeof(_Tp), |
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# endif |
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std::align_val_t(alignof(_Tp))); |
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return; |
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} |
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#endif |
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::operator delete(__p |
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#if __cpp_sized_deallocation |
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, __t * sizeof(_Tp) |
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#endif |
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); |
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} |
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|
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#if __cplusplus <= 201703L |
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size_type |
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max_size() const _GLIBCXX_USE_NOEXCEPT |
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{ return _M_max_size(); } |
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|
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#if __cplusplus >= 201103L |
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template<typename _Up, typename... _Args> |
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void |
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construct(_Up* __p, _Args&&... __args) |
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noexcept(std::is_nothrow_constructible<_Up, _Args...>::value) |
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{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } |
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|
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template<typename _Up> |
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void |
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destroy(_Up* __p) |
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noexcept(std::is_nothrow_destructible<_Up>::value) |
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{ __p->~_Up(); } |
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#else |
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// _GLIBCXX_RESOLVE_LIB_DEFECTS |
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// 402. wrong new expression in [some_] allocator::construct |
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void |
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construct(pointer __p, const _Tp& __val) |
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{ ::new((void *)__p) _Tp(__val); } |
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|
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void |
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destroy(pointer __p) { __p->~_Tp(); } |
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#endif |
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#endif // ! C++20 |
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|
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template<typename _Up> |
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friend _GLIBCXX20_CONSTEXPR bool |
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operator==(const new_allocator&, const new_allocator<_Up>&) |
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_GLIBCXX_NOTHROW |
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{ return true; } |
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|
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#if __cpp_impl_three_way_comparison < 201907L |
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template<typename _Up> |
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friend _GLIBCXX20_CONSTEXPR bool |
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operator!=(const new_allocator&, const new_allocator<_Up>&) |
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_GLIBCXX_NOTHROW |
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{ return false; } |
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#endif |
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|
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private: |
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_GLIBCXX_CONSTEXPR size_type |
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_M_max_size() const _GLIBCXX_USE_NOEXCEPT |
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{ |
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#if __PTRDIFF_MAX__ < __SIZE_MAX__ |
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return std::size_t(__PTRDIFF_MAX__) / sizeof(_Tp); |
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#else |
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return std::size_t(-1) / sizeof(_Tp); |
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#endif |
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} |
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}; |
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|
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_GLIBCXX_END_NAMESPACE_VERSION |
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} // namespace |
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|
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#endif |
