439 lines
13 KiB
C++
439 lines
13 KiB
C++
// Safe iterator implementation -*- C++ -*-
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// Copyright (C) 2011-2019 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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/** @file debug/safe_local_iterator.h
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* This file is a GNU debug extension to the Standard C++ Library.
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*/
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#ifndef _GLIBCXX_DEBUG_SAFE_LOCAL_ITERATOR_H
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#define _GLIBCXX_DEBUG_SAFE_LOCAL_ITERATOR_H 1
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#include <debug/safe_unordered_base.h>
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#define _GLIBCXX_DEBUG_VERIFY_OPERANDS(_Lhs, _Rhs) \
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_GLIBCXX_DEBUG_VERIFY(!_Lhs._M_singular() && !_Rhs._M_singular(), \
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_M_message(__msg_iter_compare_bad) \
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._M_iterator(_Lhs, "lhs") \
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._M_iterator(_Rhs, "rhs")); \
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_GLIBCXX_DEBUG_VERIFY(_Lhs._M_can_compare(_Rhs), \
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_M_message(__msg_compare_different) \
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._M_iterator(_Lhs, "lhs") \
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._M_iterator(_Rhs, "rhs")); \
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_GLIBCXX_DEBUG_VERIFY(_Lhs._M_in_same_bucket(_Rhs), \
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_M_message(__msg_local_iter_compare_bad) \
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._M_iterator(_Lhs, "lhs") \
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._M_iterator(_Rhs, "rhs"))
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namespace __gnu_debug
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{
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/** \brief Safe iterator wrapper.
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*
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* The class template %_Safe_local_iterator is a wrapper around an
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* iterator that tracks the iterator's movement among sequences and
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* checks that operations performed on the "safe" iterator are
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* legal. In additional to the basic iterator operations (which are
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* validated, and then passed to the underlying iterator),
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* %_Safe_local_iterator has member functions for iterator invalidation,
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* attaching/detaching the iterator from sequences, and querying
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* the iterator's state.
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*/
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template<typename _Iterator, typename _Sequence>
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class _Safe_local_iterator
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: private _Iterator
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, public _Safe_local_iterator_base
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{
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typedef _Iterator _Iter_base;
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typedef _Safe_local_iterator_base _Safe_base;
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typedef typename _Sequence::size_type size_type;
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typedef std::iterator_traits<_Iterator> _Traits;
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typedef std::__are_same<
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typename _Sequence::_Base::const_local_iterator,
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_Iterator> _IsConstant;
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typedef typename __gnu_cxx::__conditional_type<_IsConstant::__value,
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typename _Sequence::_Base::local_iterator,
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typename _Sequence::_Base::const_local_iterator>::__type
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_OtherIterator;
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typedef _Safe_local_iterator _Self;
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typedef _Safe_local_iterator<_OtherIterator, _Sequence> _OtherSelf;
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struct _Attach_single
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{ };
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_Safe_local_iterator(_Iterator __i, _Safe_sequence_base* __cont,
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_Attach_single) noexcept
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: _Iter_base(__i)
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{ _M_attach_single(__cont); }
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public:
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typedef _Iterator iterator_type;
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typedef typename _Traits::iterator_category iterator_category;
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typedef typename _Traits::value_type value_type;
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typedef typename _Traits::difference_type difference_type;
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typedef typename _Traits::reference reference;
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typedef typename _Traits::pointer pointer;
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/// @post the iterator is singular and unattached
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_Safe_local_iterator() noexcept : _Iter_base() { }
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/**
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* @brief Safe iterator construction from an unsafe iterator and
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* its sequence.
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*
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* @pre @p seq is not NULL
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* @post this is not singular
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*/
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_Safe_local_iterator(_Iterator __i, const _Safe_sequence_base* __cont)
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: _Iter_base(__i), _Safe_base(__cont, _S_constant())
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{
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_GLIBCXX_DEBUG_VERIFY(!this->_M_singular(),
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_M_message(__msg_init_singular)
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._M_iterator(*this, "this"));
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}
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/**
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* @brief Copy construction.
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*/
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_Safe_local_iterator(const _Safe_local_iterator& __x) noexcept
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: _Iter_base(__x.base())
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{
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// DR 408. Is vector<reverse_iterator<char*> > forbidden?
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_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
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|| __x.base() == _Iterator(),
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_M_message(__msg_init_copy_singular)
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._M_iterator(*this, "this")
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._M_iterator(__x, "other"));
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_M_attach(__x._M_sequence);
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}
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/**
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* @brief Move construction.
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* @post __x is singular and unattached
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*/
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_Safe_local_iterator(_Safe_local_iterator&& __x) noexcept
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: _Iter_base()
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{
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_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
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|| __x.base() == _Iterator(),
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_M_message(__msg_init_copy_singular)
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._M_iterator(*this, "this")
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._M_iterator(__x, "other"));
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auto __cont = __x._M_sequence;
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__x._M_detach();
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std::swap(base(), __x.base());
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_M_attach(__cont);
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}
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/**
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* @brief Converting constructor from a mutable iterator to a
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* constant iterator.
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*/
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template<typename _MutableIterator>
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_Safe_local_iterator(
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const _Safe_local_iterator<_MutableIterator,
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typename __gnu_cxx::__enable_if<_IsConstant::__value &&
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std::__are_same<_MutableIterator, _OtherIterator>::__value,
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_Sequence>::__type>& __x) noexcept
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: _Iter_base(__x.base())
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{
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// DR 408. Is vector<reverse_iterator<char*> > forbidden?
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_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
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|| __x.base() == _MutableIterator(),
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_M_message(__msg_init_const_singular)
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._M_iterator(*this, "this")
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._M_iterator(__x, "other"));
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_M_attach(__x._M_sequence);
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}
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/**
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* @brief Copy assignment.
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*/
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_Safe_local_iterator&
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operator=(const _Safe_local_iterator& __x)
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{
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// DR 408. Is vector<reverse_iterator<char*> > forbidden?
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_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
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|| __x.base() == _Iterator(),
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_M_message(__msg_copy_singular)
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._M_iterator(*this, "this")
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._M_iterator(__x, "other"));
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if (this->_M_sequence && this->_M_sequence == __x._M_sequence)
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{
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__gnu_cxx::__scoped_lock __l(this->_M_get_mutex());
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base() = __x.base();
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_M_version = __x._M_sequence->_M_version;
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}
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else
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{
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_M_detach();
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base() = __x.base();
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_M_attach(__x._M_sequence);
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}
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return *this;
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}
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/**
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* @brief Move assignment.
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* @post __x is singular and unattached
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*/
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_Safe_local_iterator&
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operator=(_Safe_local_iterator&& __x) noexcept
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{
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_GLIBCXX_DEBUG_VERIFY(this != &__x,
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_M_message(__msg_self_move_assign)
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._M_iterator(*this, "this"));
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_GLIBCXX_DEBUG_VERIFY(!__x._M_singular()
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|| __x.base() == _Iterator(),
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_M_message(__msg_copy_singular)
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._M_iterator(*this, "this")
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._M_iterator(__x, "other"));
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if (this->_M_sequence && this->_M_sequence == __x._M_sequence)
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{
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__gnu_cxx::__scoped_lock __l(this->_M_get_mutex());
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base() = __x.base();
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_M_version = __x._M_sequence->_M_version;
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}
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else
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{
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_M_detach();
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base() = __x.base();
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_M_attach(__x._M_sequence);
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}
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__x._M_detach();
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__x.base() = _Iterator();
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return *this;
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}
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/**
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* @brief Iterator dereference.
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* @pre iterator is dereferenceable
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*/
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reference
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operator*() const
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{
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_GLIBCXX_DEBUG_VERIFY(this->_M_dereferenceable(),
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_M_message(__msg_bad_deref)
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._M_iterator(*this, "this"));
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return *base();
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}
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/**
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* @brief Iterator dereference.
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* @pre iterator is dereferenceable
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*/
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pointer
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operator->() const
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{
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_GLIBCXX_DEBUG_VERIFY(this->_M_dereferenceable(),
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_M_message(__msg_bad_deref)
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._M_iterator(*this, "this"));
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return base().operator->();
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}
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// ------ Input iterator requirements ------
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/**
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* @brief Iterator preincrement
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* @pre iterator is incrementable
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*/
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_Safe_local_iterator&
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operator++()
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{
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_GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(),
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_M_message(__msg_bad_inc)
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._M_iterator(*this, "this"));
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__gnu_cxx::__scoped_lock __l(this->_M_get_mutex());
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++base();
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return *this;
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}
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/**
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* @brief Iterator postincrement
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* @pre iterator is incrementable
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*/
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_Safe_local_iterator
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operator++(int)
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{
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_GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(),
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_M_message(__msg_bad_inc)
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._M_iterator(*this, "this"));
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__gnu_cxx::__scoped_lock __l(this->_M_get_mutex());
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return _Safe_local_iterator(base()++, this->_M_sequence,
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_Attach_single());
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}
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// ------ Utilities ------
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/// Determine if this is a constant iterator.
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static constexpr bool
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_S_constant()
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{ return _IsConstant::__value; }
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/**
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* @brief Return the underlying iterator
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*/
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_Iterator&
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base() noexcept { return *this; }
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const _Iterator&
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base() const noexcept { return *this; }
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/**
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* @brief Return the bucket
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*/
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size_type
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bucket() const { return base()._M_get_bucket(); }
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/**
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* @brief Conversion to underlying non-debug iterator to allow
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* better interaction with non-debug containers.
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*/
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operator _Iterator() const { return *this; }
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/** Attach iterator to the given sequence. */
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void
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_M_attach(_Safe_sequence_base* __seq)
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{ _Safe_base::_M_attach(__seq, _S_constant()); }
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/** Likewise, but not thread-safe. */
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void
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_M_attach_single(_Safe_sequence_base* __seq)
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{ _Safe_base::_M_attach_single(__seq, _S_constant()); }
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/// Is the iterator dereferenceable?
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bool
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_M_dereferenceable() const
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{ return !this->_M_singular() && !_M_is_end(); }
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/// Is the iterator incrementable?
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bool
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_M_incrementable() const
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{ return !this->_M_singular() && !_M_is_end(); }
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// Is the iterator range [*this, __rhs) valid?
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bool
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_M_valid_range(const _Safe_local_iterator& __rhs,
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std::pair<difference_type,
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_Distance_precision>& __dist_info) const;
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// Get distance to __rhs.
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typename _Distance_traits<_Iterator>::__type
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_M_get_distance_to(const _Safe_local_iterator& __rhs) const;
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// The sequence this iterator references.
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typename __gnu_cxx::__conditional_type<
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_IsConstant::__value, const _Sequence*, _Sequence*>::__type
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_M_get_sequence() const
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{ return static_cast<_Sequence*>(_M_sequence); }
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/// Is this iterator equal to the sequence's begin(bucket) iterator?
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bool _M_is_begin() const
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{ return base() == _M_get_sequence()->_M_base().begin(bucket()); }
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/// Is this iterator equal to the sequence's end(bucket) iterator?
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bool _M_is_end() const
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{ return base() == _M_get_sequence()->_M_base().end(bucket()); }
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/// Is this iterator part of the same bucket as the other one?
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template<typename _Other>
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bool
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_M_in_same_bucket(const _Safe_local_iterator<_Other,
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_Sequence>& __other) const
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{ return bucket() == __other.bucket(); }
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friend inline bool
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operator==(const _Self& __lhs, const _OtherSelf& __rhs) noexcept
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{
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_GLIBCXX_DEBUG_VERIFY_OPERANDS(__lhs, __rhs);
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return __lhs.base() == __rhs.base();
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}
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friend inline bool
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operator==(const _Self& __lhs, const _Self& __rhs) noexcept
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{
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_GLIBCXX_DEBUG_VERIFY_OPERANDS(__lhs, __rhs);
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return __lhs.base() == __rhs.base();
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}
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friend inline bool
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operator!=(const _Self& __lhs, const _OtherSelf& __rhs) noexcept
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{
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_GLIBCXX_DEBUG_VERIFY_OPERANDS(__lhs, __rhs);
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return __lhs.base() != __rhs.base();
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}
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friend inline bool
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operator!=(const _Self& __lhs, const _Self& __rhs) noexcept
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{
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_GLIBCXX_DEBUG_VERIFY_OPERANDS(__lhs, __rhs);
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return __lhs.base() != __rhs.base();
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}
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};
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/** Safe local iterators know how to check if they form a valid range. */
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template<typename _Iterator, typename _Sequence>
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inline bool
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__valid_range(const _Safe_local_iterator<_Iterator, _Sequence>& __first,
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const _Safe_local_iterator<_Iterator, _Sequence>& __last,
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typename _Distance_traits<_Iterator>::__type& __dist_info)
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{ return __first._M_valid_range(__last, __dist_info); }
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template<typename _Iterator, typename _Sequence>
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inline bool
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__valid_range(const _Safe_local_iterator<_Iterator, _Sequence>& __first,
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const _Safe_local_iterator<_Iterator, _Sequence>& __last)
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{
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typename _Distance_traits<_Iterator>::__type __dist_info;
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return __first._M_valid_range(__last, __dist_info);
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}
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#if __cplusplus < 201103L
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template<typename _Iterator, typename _Sequence>
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struct _Unsafe_type<_Safe_local_iterator<_Iterator, _Sequence> >
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{ typedef _Iterator _Type; };
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#endif
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template<typename _Iterator, typename _Sequence>
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inline _Iterator
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__unsafe(const _Safe_local_iterator<_Iterator, _Sequence>& __it)
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{ return __it.base(); }
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} // namespace __gnu_debug
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#undef _GLIBCXX_DEBUG_VERIFY_OPERANDS
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#include <debug/safe_local_iterator.tcc>
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#endif
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