241 lines
6.7 KiB
C++
241 lines
6.7 KiB
C++
// Allocators -*- C++ -*-
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// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
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// 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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// 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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// 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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// 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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* Copyright (c) 1996-1997
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file bits/allocator.h
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* This is an internal header file, included by other library headers.
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* Do not attempt to use it directly. @headername{memory}
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*/
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#ifndef _ALLOCATOR_H
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#define _ALLOCATOR_H 1
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// Define the base class to std::allocator.
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#include <bits/c++allocator.h>
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#ifdef __GXX_EXPERIMENTAL_CXX0X__
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#include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE
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#endif
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/**
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* @defgroup allocators Allocators
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* @ingroup memory
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*
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* Classes encapsulating memory operations.
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*/
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template<typename _Tp>
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class allocator;
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/// allocator<void> specialization.
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template<>
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class allocator<void>
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{
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public:
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typedef size_t size_type;
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typedef ptrdiff_t difference_type;
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typedef void* pointer;
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typedef const void* const_pointer;
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typedef void value_type;
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template<typename _Tp1>
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struct rebind
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{ typedef allocator<_Tp1> other; };
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};
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/**
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* @brief The @a standard allocator, as per [20.4].
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* @ingroup allocators
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*
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* Further details:
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* http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
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*/
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template<typename _Tp>
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class allocator: public __glibcxx_base_allocator<_Tp>
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{
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public:
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typedef size_t size_type;
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typedef ptrdiff_t difference_type;
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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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typedef _Tp value_type;
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template<typename _Tp1>
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struct rebind
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{ typedef allocator<_Tp1> other; };
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allocator() throw() { }
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allocator(const allocator& __a) throw()
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: __glibcxx_base_allocator<_Tp>(__a) { }
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template<typename _Tp1>
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allocator(const allocator<_Tp1>&) throw() { }
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~allocator() throw() { }
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// Inherit everything else.
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};
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template<typename _T1, typename _T2>
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inline bool
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operator==(const allocator<_T1>&, const allocator<_T2>&)
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{ return true; }
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template<typename _Tp>
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inline bool
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operator==(const allocator<_Tp>&, const allocator<_Tp>&)
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{ return true; }
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template<typename _T1, typename _T2>
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inline bool
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operator!=(const allocator<_T1>&, const allocator<_T2>&)
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{ return false; }
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template<typename _Tp>
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inline bool
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operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
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{ return false; }
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// Inhibit implicit instantiations for required instantiations,
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// which are defined via explicit instantiations elsewhere.
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// NB: This syntax is a GNU extension.
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#if _GLIBCXX_EXTERN_TEMPLATE
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extern template class allocator<char>;
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extern template class allocator<wchar_t>;
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#endif
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// Undefine.
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#undef __glibcxx_base_allocator
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// To implement Option 3 of DR 431.
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template<typename _Alloc, bool = __is_empty(_Alloc)>
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struct __alloc_swap
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{ static void _S_do_it(_Alloc&, _Alloc&) { } };
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template<typename _Alloc>
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struct __alloc_swap<_Alloc, false>
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{
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static void
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_S_do_it(_Alloc& __one, _Alloc& __two)
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{
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// Precondition: swappable allocators.
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if (__one != __two)
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swap(__one, __two);
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}
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};
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// Optimize for stateless allocators.
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template<typename _Alloc, bool = __is_empty(_Alloc)>
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struct __alloc_neq
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{
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static bool
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_S_do_it(const _Alloc&, const _Alloc&)
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{ return false; }
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};
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template<typename _Alloc>
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struct __alloc_neq<_Alloc, false>
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{
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static bool
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_S_do_it(const _Alloc& __one, const _Alloc& __two)
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{ return __one != __two; }
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};
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#ifdef __GXX_EXPERIMENTAL_CXX0X__
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// A very basic implementation for now. In general we have to wait for
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// the availability of the infrastructure described in N2983: we should
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// try when either T has a move constructor which cannot throw or T is
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// CopyContructible.
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// NB: This code doesn't properly belong here, we should find a more
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// suited place common to std::vector and std::deque.
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template<typename _Tp,
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bool = __has_trivial_copy(typename _Tp::value_type)>
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struct __shrink_to_fit
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{ static void _S_do_it(_Tp&) { } };
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template<typename _Tp>
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struct __shrink_to_fit<_Tp, true>
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{
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static void
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_S_do_it(_Tp& __v)
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{
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__try
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{ _Tp(__v).swap(__v); }
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__catch(...) { }
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}
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};
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/// [allocator.tag]
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struct allocator_arg_t { };
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constexpr allocator_arg_t allocator_arg = allocator_arg_t();
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_GLIBCXX_HAS_NESTED_TYPE(allocator_type)
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template<typename _Tp, typename _Alloc,
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bool = __has_allocator_type<_Tp>::value>
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struct __uses_allocator_helper
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: public false_type { };
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template<typename _Tp, typename _Alloc>
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struct __uses_allocator_helper<_Tp, _Alloc, true>
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: public integral_constant<bool, is_convertible<_Alloc,
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typename _Tp::allocator_type>::value>
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{ };
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/// [allocator.uses.trait]
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template<typename _Tp, typename _Alloc>
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struct uses_allocator
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: public integral_constant<bool,
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__uses_allocator_helper<_Tp, _Alloc>::value>
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{ };
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#endif
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace
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#endif
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