Edit File: safe_iterator.h
// Safe iterator implementation -*- C++ -*- // Copyright (C) 2003-2013 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/>. /** @file debug/safe_iterator.h * This file is a GNU debug extension to the Standard C++ Library. */ #ifndef _GLIBCXX_DEBUG_SAFE_ITERATOR_H #define _GLIBCXX_DEBUG_SAFE_ITERATOR_H 1 #include <debug/debug.h> #include <debug/macros.h> #include <debug/functions.h> #include <debug/safe_base.h> #include <bits/stl_pair.h> #include <ext/type_traits.h> namespace __gnu_debug { /** Helper struct to deal with sequence offering a before_begin * iterator. **/ template <typename _Sequence> struct _BeforeBeginHelper { typedef typename _Sequence::const_iterator _It; typedef typename _It::iterator_type _BaseIt; static bool _S_Is(_BaseIt, const _Sequence*) { return false; } static bool _S_Is_Beginnest(_BaseIt __it, const _Sequence* __seq) { return __it == __seq->_M_base().begin(); } }; /** Iterators that derive from _Safe_iterator_base but that aren't * _Safe_iterators can be determined singular or non-singular via * _Safe_iterator_base. */ inline bool __check_singular_aux(const _Safe_iterator_base* __x) { return __x->_M_singular(); } /** The precision to which we can calculate the distance between * two iterators. */ enum _Distance_precision { __dp_equality, //< Can compare iterator equality, only __dp_sign, //< Can determine equality and ordering __dp_exact //< Can determine distance precisely }; /** Determine the distance between two iterators with some known * precision. */ template<typename _Iterator1, typename _Iterator2> inline std::pair<typename std::iterator_traits<_Iterator1>::difference_type, _Distance_precision> __get_distance(const _Iterator1& __lhs, const _Iterator2& __rhs, std::random_access_iterator_tag) { return std::make_pair(__rhs - __lhs, __dp_exact); } template<typename _Iterator1, typename _Iterator2> inline std::pair<typename std::iterator_traits<_Iterator1>::difference_type, _Distance_precision> __get_distance(const _Iterator1& __lhs, const _Iterator2& __rhs, std::forward_iterator_tag) { return std::make_pair(__lhs == __rhs? 0 : 1, __dp_equality); } template<typename _Iterator1, typename _Iterator2> inline std::pair<typename std::iterator_traits<_Iterator1>::difference_type, _Distance_precision> __get_distance(const _Iterator1& __lhs, const _Iterator2& __rhs) { typedef typename std::iterator_traits<_Iterator1>::iterator_category _Category; return __get_distance(__lhs, __rhs, _Category()); } /** \brief Safe iterator wrapper. * * The class template %_Safe_iterator is a wrapper around an * iterator that tracks the iterator's movement among sequences and * checks that operations performed on the "safe" iterator are * legal. In additional to the basic iterator operations (which are * validated, and then passed to the underlying iterator), * %_Safe_iterator has member functions for iterator invalidation, * attaching/detaching the iterator from sequences, and querying * the iterator's state. */ template<typename _Iterator, typename _Sequence> class _Safe_iterator : public _Safe_iterator_base { typedef _Safe_iterator _Self; /// The underlying iterator _Iterator _M_current; /// Determine if this is a constant iterator. bool _M_constant() const { typedef typename _Sequence::const_iterator const_iterator; return std::__are_same<const_iterator, _Safe_iterator>::__value; } typedef std::iterator_traits<_Iterator> _Traits; public: typedef _Iterator iterator_type; typedef typename _Traits::iterator_category iterator_category; typedef typename _Traits::value_type value_type; typedef typename _Traits::difference_type difference_type; typedef typename _Traits::reference reference; typedef typename _Traits::pointer pointer; /// @post the iterator is singular and unattached _Safe_iterator() : _M_current() { } /** * @brief Safe iterator construction from an unsafe iterator and * its sequence. * * @pre @p seq is not NULL * @post this is not singular */ _Safe_iterator(const _Iterator& __i, const _Sequence* __seq) : _Safe_iterator_base(__seq, _M_constant()), _M_current(__i) { _GLIBCXX_DEBUG_VERIFY(! this->_M_singular(), _M_message(__msg_init_singular) ._M_iterator(*this, "this")); } /** * @brief Copy construction. */ _Safe_iterator(const _Safe_iterator& __x) : _Safe_iterator_base(__x, _M_constant()), _M_current(__x._M_current) { // _GLIBCXX_RESOLVE_LIB_DEFECTS // DR 408. Is vector<reverse_iterator<char*> > forbidden? _GLIBCXX_DEBUG_VERIFY(!__x._M_singular() || __x._M_current == _Iterator(), _M_message(__msg_init_copy_singular) ._M_iterator(*this, "this") ._M_iterator(__x, "other")); } #if __cplusplus >= 201103L /** * @brief Move construction. * @post __x is singular and unattached */ _Safe_iterator(_Safe_iterator&& __x) : _M_current() { _GLIBCXX_DEBUG_VERIFY(!__x._M_singular() || __x._M_current == _Iterator(), _M_message(__msg_init_copy_singular) ._M_iterator(*this, "this") ._M_iterator(__x, "other")); std::swap(_M_current, __x._M_current); this->_M_attach(__x._M_sequence); __x._M_detach(); } #endif /** * @brief Converting constructor from a mutable iterator to a * constant iterator. */ template<typename _MutableIterator> _Safe_iterator( const _Safe_iterator<_MutableIterator, typename __gnu_cxx::__enable_if<(std::__are_same<_MutableIterator, typename _Sequence::iterator::iterator_type>::__value), _Sequence>::__type>& __x) : _Safe_iterator_base(__x, _M_constant()), _M_current(__x.base()) { // _GLIBCXX_RESOLVE_LIB_DEFECTS // DR 408. Is vector<reverse_iterator<char*> > forbidden? _GLIBCXX_DEBUG_VERIFY(!__x._M_singular() || __x.base() == _Iterator(), _M_message(__msg_init_const_singular) ._M_iterator(*this, "this") ._M_iterator(__x, "other")); } /** * @brief Copy assignment. */ _Safe_iterator& operator=(const _Safe_iterator& __x) { // _GLIBCXX_RESOLVE_LIB_DEFECTS // DR 408. Is vector<reverse_iterator<char*> > forbidden? _GLIBCXX_DEBUG_VERIFY(!__x._M_singular() || __x._M_current == _Iterator(), _M_message(__msg_copy_singular) ._M_iterator(*this, "this") ._M_iterator(__x, "other")); _M_current = __x._M_current; this->_M_attach(__x._M_sequence); return *this; } #if __cplusplus >= 201103L /** * @brief Move assignment. * @post __x is singular and unattached */ _Safe_iterator& operator=(_Safe_iterator&& __x) { _GLIBCXX_DEBUG_VERIFY(this != &__x, _M_message(__msg_self_move_assign) ._M_iterator(*this, "this")); _GLIBCXX_DEBUG_VERIFY(!__x._M_singular() || __x._M_current == _Iterator(), _M_message(__msg_copy_singular) ._M_iterator(*this, "this") ._M_iterator(__x, "other")); _M_current = __x._M_current; _M_attach(__x._M_sequence); __x._M_detach(); __x._M_current = _Iterator(); return *this; } #endif /** * @brief Iterator dereference. * @pre iterator is dereferenceable */ reference operator*() const { _GLIBCXX_DEBUG_VERIFY(this->_M_dereferenceable(), _M_message(__msg_bad_deref) ._M_iterator(*this, "this")); return *_M_current; } /** * @brief Iterator dereference. * @pre iterator is dereferenceable * @todo Make this correct w.r.t. iterators that return proxies * @todo Use addressof() instead of & operator */ pointer operator->() const { _GLIBCXX_DEBUG_VERIFY(this->_M_dereferenceable(), _M_message(__msg_bad_deref) ._M_iterator(*this, "this")); return &*_M_current; } // ------ Input iterator requirements ------ /** * @brief Iterator preincrement * @pre iterator is incrementable */ _Safe_iterator& operator++() { _GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(), _M_message(__msg_bad_inc) ._M_iterator(*this, "this")); ++_M_current; return *this; } /** * @brief Iterator postincrement * @pre iterator is incrementable */ _Safe_iterator operator++(int) { _GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(), _M_message(__msg_bad_inc) ._M_iterator(*this, "this")); _Safe_iterator __tmp(*this); ++_M_current; return __tmp; } // ------ Bidirectional iterator requirements ------ /** * @brief Iterator predecrement * @pre iterator is decrementable */ _Safe_iterator& operator--() { _GLIBCXX_DEBUG_VERIFY(this->_M_decrementable(), _M_message(__msg_bad_dec) ._M_iterator(*this, "this")); --_M_current; return *this; } /** * @brief Iterator postdecrement * @pre iterator is decrementable */ _Safe_iterator operator--(int) { _GLIBCXX_DEBUG_VERIFY(this->_M_decrementable(), _M_message(__msg_bad_dec) ._M_iterator(*this, "this")); _Safe_iterator __tmp(*this); --_M_current; return __tmp; } // ------ Random access iterator requirements ------ reference operator[](const difference_type& __n) const { _GLIBCXX_DEBUG_VERIFY(this->_M_can_advance(__n) && this->_M_can_advance(__n+1), _M_message(__msg_iter_subscript_oob) ._M_iterator(*this)._M_integer(__n)); return _M_current[__n]; } _Safe_iterator& operator+=(const difference_type& __n) { _GLIBCXX_DEBUG_VERIFY(this->_M_can_advance(__n), _M_message(__msg_advance_oob) ._M_iterator(*this)._M_integer(__n)); _M_current += __n; return *this; } _Safe_iterator operator+(const difference_type& __n) const { _Safe_iterator __tmp(*this); __tmp += __n; return __tmp; } _Safe_iterator& operator-=(const difference_type& __n) { _GLIBCXX_DEBUG_VERIFY(this->_M_can_advance(-__n), _M_message(__msg_retreat_oob) ._M_iterator(*this)._M_integer(__n)); _M_current += -__n; return *this; } _Safe_iterator operator-(const difference_type& __n) const { _Safe_iterator __tmp(*this); __tmp -= __n; return __tmp; } // ------ Utilities ------ /** * @brief Return the underlying iterator */ _Iterator base() const { return _M_current; } /** * @brief Conversion to underlying non-debug iterator to allow * better interaction with non-debug containers. */ operator _Iterator() const { return _M_current; } /** Attach iterator to the given sequence. */ void _M_attach(_Safe_sequence_base* __seq) { _Safe_iterator_base::_M_attach(__seq, _M_constant()); } /** Likewise, but not thread-safe. */ void _M_attach_single(_Safe_sequence_base* __seq) { _Safe_iterator_base::_M_attach_single(__seq, _M_constant()); } /// Is the iterator dereferenceable? bool _M_dereferenceable() const { return !this->_M_singular() && !_M_is_end() && !_M_is_before_begin(); } /// Is the iterator before a dereferenceable one? bool _M_before_dereferenceable() const { if (this->_M_incrementable()) { _Iterator __base = base(); return ++__base != _M_get_sequence()->_M_base().end(); } return false; } /// Is the iterator incrementable? bool _M_incrementable() const { return !this->_M_singular() && !_M_is_end(); } // Is the iterator decrementable? bool _M_decrementable() const { return !_M_singular() && !_M_is_begin(); } // Can we advance the iterator @p __n steps (@p __n may be negative) bool _M_can_advance(const difference_type& __n) const; // Is the iterator range [*this, __rhs) valid? template<typename _Other> bool _M_valid_range(const _Safe_iterator<_Other, _Sequence>& __rhs) const; // The sequence this iterator references. const _Sequence* _M_get_sequence() const { return static_cast<const _Sequence*>(_M_sequence); } /// Is this iterator equal to the sequence's begin() iterator? bool _M_is_begin() const { return base() == _M_get_sequence()->_M_base().begin(); } /// Is this iterator equal to the sequence's end() iterator? bool _M_is_end() const { return base() == _M_get_sequence()->_M_base().end(); } /// Is this iterator equal to the sequence's before_begin() iterator if /// any? bool _M_is_before_begin() const { return _BeforeBeginHelper<_Sequence>::_S_Is(base(), _M_get_sequence()); } /// Is this iterator equal to the sequence's before_begin() iterator if /// any or begin() otherwise? bool _M_is_beginnest() const { return _BeforeBeginHelper<_Sequence>::_S_Is_Beginnest(base(), _M_get_sequence()); } }; template<typename _IteratorL, typename _IteratorR, typename _Sequence> inline bool operator==(const _Safe_iterator<_IteratorL, _Sequence>& __lhs, const _Safe_iterator<_IteratorR, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_compare_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_compare_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() == __rhs.base(); } template<typename _Iterator, typename _Sequence> inline bool operator==(const _Safe_iterator<_Iterator, _Sequence>& __lhs, const _Safe_iterator<_Iterator, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_compare_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_compare_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() == __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Sequence> inline bool operator!=(const _Safe_iterator<_IteratorL, _Sequence>& __lhs, const _Safe_iterator<_IteratorR, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_compare_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_compare_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() != __rhs.base(); } template<typename _Iterator, typename _Sequence> inline bool operator!=(const _Safe_iterator<_Iterator, _Sequence>& __lhs, const _Safe_iterator<_Iterator, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_compare_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_compare_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() != __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Sequence> inline bool operator<(const _Safe_iterator<_IteratorL, _Sequence>& __lhs, const _Safe_iterator<_IteratorR, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_order_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_order_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() < __rhs.base(); } template<typename _Iterator, typename _Sequence> inline bool operator<(const _Safe_iterator<_Iterator, _Sequence>& __lhs, const _Safe_iterator<_Iterator, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_order_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_order_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() < __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Sequence> inline bool operator<=(const _Safe_iterator<_IteratorL, _Sequence>& __lhs, const _Safe_iterator<_IteratorR, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_order_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_order_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() <= __rhs.base(); } template<typename _Iterator, typename _Sequence> inline bool operator<=(const _Safe_iterator<_Iterator, _Sequence>& __lhs, const _Safe_iterator<_Iterator, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_order_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_order_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() <= __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Sequence> inline bool operator>(const _Safe_iterator<_IteratorL, _Sequence>& __lhs, const _Safe_iterator<_IteratorR, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_order_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_order_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() > __rhs.base(); } template<typename _Iterator, typename _Sequence> inline bool operator>(const _Safe_iterator<_Iterator, _Sequence>& __lhs, const _Safe_iterator<_Iterator, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_order_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_order_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() > __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Sequence> inline bool operator>=(const _Safe_iterator<_IteratorL, _Sequence>& __lhs, const _Safe_iterator<_IteratorR, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_order_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_order_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() >= __rhs.base(); } template<typename _Iterator, typename _Sequence> inline bool operator>=(const _Safe_iterator<_Iterator, _Sequence>& __lhs, const _Safe_iterator<_Iterator, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_iter_order_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_order_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() >= __rhs.base(); } // _GLIBCXX_RESOLVE_LIB_DEFECTS // According to the resolution of DR179 not only the various comparison // operators but also operator- must accept mixed iterator/const_iterator // parameters. template<typename _IteratorL, typename _IteratorR, typename _Sequence> inline typename _Safe_iterator<_IteratorL, _Sequence>::difference_type operator-(const _Safe_iterator<_IteratorL, _Sequence>& __lhs, const _Safe_iterator<_IteratorR, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_distance_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_distance_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() - __rhs.base(); } template<typename _Iterator, typename _Sequence> inline typename _Safe_iterator<_Iterator, _Sequence>::difference_type operator-(const _Safe_iterator<_Iterator, _Sequence>& __lhs, const _Safe_iterator<_Iterator, _Sequence>& __rhs) { _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(), _M_message(__msg_distance_bad) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs), _M_message(__msg_distance_different) ._M_iterator(__lhs, "lhs") ._M_iterator(__rhs, "rhs")); return __lhs.base() - __rhs.base(); } template<typename _Iterator, typename _Sequence> inline _Safe_iterator<_Iterator, _Sequence> operator+(typename _Safe_iterator<_Iterator,_Sequence>::difference_type __n, const _Safe_iterator<_Iterator, _Sequence>& __i) { return __i + __n; } } // namespace __gnu_debug #include <debug/safe_iterator.tcc> #endif