📄 stl_iterator.h
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* This wrapper function helps in creating back_insert_iterator instances. * Typing the name of the %iterator requires knowing the precise full * type of the container, which can be tedious and impedes generic * programming. Using this function lets you take advantage of automatic * template parameter deduction, making the compiler match the correct * types for you. */ template<typename _Container> inline back_insert_iterator<_Container> back_inserter(_Container& __x) { return back_insert_iterator<_Container>(__x); } /** * @brief Turns assignment into insertion. * * These are output iterators, constructed from a container-of-T. * Assigning a T to the iterator prepends it to the container using * push_front. * * Tip: Using the front_inserter function to create these iterators can * save typing. */ template<typename _Container> class front_insert_iterator : public iterator<output_iterator_tag, void, void, void, void> { protected: _Container* container; public: /// A nested typedef for the type of whatever container you used. typedef _Container container_type; /// The only way to create this %iterator is with a container. explicit front_insert_iterator(_Container& __x) : container(&__x) { } /** * @param value An instance of whatever type * container_type::const_reference is; presumably a * reference-to-const T for container<T>. * @return This %iterator, for chained operations. * * This kind of %iterator doesn't really have a "position" in the * container (you can think of the position as being permanently at * the front, if you like). Assigning a value to the %iterator will * always prepend the value to the front of the container. */ front_insert_iterator& operator=(typename _Container::const_reference __value) { container->push_front(__value); return *this; } /// Simply returns *this. front_insert_iterator& operator*() { return *this; } /// Simply returns *this. (This %iterator does not "move".) front_insert_iterator& operator++() { return *this; } /// Simply returns *this. (This %iterator does not "move".) front_insert_iterator operator++(int) { return *this; } }; /** * @param x A container of arbitrary type. * @return An instance of front_insert_iterator working on @p x. * * This wrapper function helps in creating front_insert_iterator instances. * Typing the name of the %iterator requires knowing the precise full * type of the container, which can be tedious and impedes generic * programming. Using this function lets you take advantage of automatic * template parameter deduction, making the compiler match the correct * types for you. */ template<typename _Container> inline front_insert_iterator<_Container> front_inserter(_Container& __x) { return front_insert_iterator<_Container>(__x); } /** * @brief Turns assignment into insertion. * * These are output iterators, constructed from a container-of-T. * Assigning a T to the iterator inserts it in the container at the * %iterator's position, rather than overwriting the value at that * position. * * (Sequences will actually insert a @e copy of the value before the * %iterator's position.) * * Tip: Using the inserter function to create these iterators can * save typing. */ template<typename _Container> class insert_iterator : public iterator<output_iterator_tag, void, void, void, void> { protected: _Container* container; typename _Container::iterator iter; public: /// A nested typedef for the type of whatever container you used. typedef _Container container_type; /** * The only way to create this %iterator is with a container and an * initial position (a normal %iterator into the container). */ insert_iterator(_Container& __x, typename _Container::iterator __i) : container(&__x), iter(__i) {} /** * @param value An instance of whatever type * container_type::const_reference is; presumably a * reference-to-const T for container<T>. * @return This %iterator, for chained operations. * * This kind of %iterator maintains its own position in the * container. Assigning a value to the %iterator will insert the * value into the container at the place before the %iterator. * * The position is maintained such that subsequent assignments will * insert values immediately after one another. For example, * @code * // vector v contains A and Z * * insert_iterator i (v, ++v.begin()); * i = 1; * i = 2; * i = 3; * * // vector v contains A, 1, 2, 3, and Z * @endcode */ insert_iterator& operator=(const typename _Container::const_reference __value) { iter = container->insert(iter, __value); ++iter; return *this; } /// Simply returns *this. insert_iterator& operator*() { return *this; } /// Simply returns *this. (This %iterator does not "move".) insert_iterator& operator++() { return *this; } /// Simply returns *this. (This %iterator does not "move".) insert_iterator& operator++(int) { return *this; } }; /** * @param x A container of arbitrary type. * @return An instance of insert_iterator working on @p x. * * This wrapper function helps in creating insert_iterator instances. * Typing the name of the %iterator requires knowing the precise full * type of the container, which can be tedious and impedes generic * programming. Using this function lets you take advantage of automatic * template parameter deduction, making the compiler match the correct * types for you. */ template<typename _Container, typename _Iterator> inline insert_iterator<_Container> inserter(_Container& __x, _Iterator __i) { return insert_iterator<_Container>(__x, typename _Container::iterator(__i)); }} // namespace stdnamespace __gnu_cxx{ // This iterator adapter is 'normal' in the sense that it does not // change the semantics of any of the operators of its iterator // parameter. Its primary purpose is to convert an iterator that is // not a class, e.g. a pointer, into an iterator that is a class. // The _Container parameter exists solely so that different containers // using this template can instantiate different types, even if the // _Iterator parameter is the same. using std::iterator_traits; using std::iterator; template<typename _Iterator, typename _Container> class __normal_iterator { protected: _Iterator _M_current; public: typedef typename iterator_traits<_Iterator>::iterator_category iterator_category; typedef typename iterator_traits<_Iterator>::value_type value_type; typedef typename iterator_traits<_Iterator>::difference_type difference_type; typedef typename iterator_traits<_Iterator>::reference reference; typedef typename iterator_traits<_Iterator>::pointer pointer; __normal_iterator() : _M_current(_Iterator()) { } explicit __normal_iterator(const _Iterator& __i) : _M_current(__i) { } // Allow iterator to const_iterator conversion template<typename _Iter> inline __normal_iterator(const __normal_iterator<_Iter, _Container>& __i) : _M_current(__i.base()) { } // Forward iterator requirements reference operator*() const { return *_M_current; } pointer operator->() const { return _M_current; } __normal_iterator& operator++() { ++_M_current; return *this; } __normal_iterator operator++(int) { return __normal_iterator(_M_current++); } // Bidirectional iterator requirements __normal_iterator& operator--() { --_M_current; return *this; } __normal_iterator operator--(int) { return __normal_iterator(_M_current--); } // Random access iterator requirements reference operator[](const difference_type& __n) const { return _M_current[__n]; } __normal_iterator& operator+=(const difference_type& __n) { _M_current += __n; return *this; } __normal_iterator operator+(const difference_type& __n) const { return __normal_iterator(_M_current + __n); } __normal_iterator& operator-=(const difference_type& __n) { _M_current -= __n; return *this; } __normal_iterator operator-(const difference_type& __n) const { return __normal_iterator(_M_current - __n); } const _Iterator& base() const { return _M_current; } }; // Note: In what follows, the left- and right-hand-side iterators are // allowed to vary in types (conceptually in cv-qualification) so that // comparaison between cv-qualified and non-cv-qualified iterators be // valid. However, the greedy and unfriendly operators in std::rel_ops // will make overload resolution ambiguous (when in scope) if we don't // provide overloads whose operands are of the same type. Can someone // remind me what generic programming is about? -- Gaby // Forward iterator requirements template<typename _IteratorL, typename _IteratorR, typename _Container> inline bool operator==(const __normal_iterator<_IteratorL, _Container>& __lhs, const __normal_iterator<_IteratorR, _Container>& __rhs) { return __lhs.base() == __rhs.base(); } template<typename _Iterator, typename _Container> inline bool operator==(const __normal_iterator<_Iterator, _Container>& __lhs, const __normal_iterator<_Iterator, _Container>& __rhs) { return __lhs.base() == __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Container> inline bool operator!=(const __normal_iterator<_IteratorL, _Container>& __lhs, const __normal_iterator<_IteratorR, _Container>& __rhs) { return __lhs.base() != __rhs.base(); } template<typename _Iterator, typename _Container> inline bool operator!=(const __normal_iterator<_Iterator, _Container>& __lhs, const __normal_iterator<_Iterator, _Container>& __rhs) { return __lhs.base() != __rhs.base(); } // Random access iterator requirements template<typename _IteratorL, typename _IteratorR, typename _Container> inline bool operator<(const __normal_iterator<_IteratorL, _Container>& __lhs, const __normal_iterator<_IteratorR, _Container>& __rhs) { return __lhs.base() < __rhs.base(); } template<typename _Iterator, typename _Container> inline bool operator<(const __normal_iterator<_Iterator, _Container>& __lhs, const __normal_iterator<_Iterator, _Container>& __rhs) { return __lhs.base() < __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Container> inline bool operator>(const __normal_iterator<_IteratorL, _Container>& __lhs, const __normal_iterator<_IteratorR, _Container>& __rhs) { return __lhs.base() > __rhs.base(); } template<typename _Iterator, typename _Container> inline bool operator>(const __normal_iterator<_Iterator, _Container>& __lhs, const __normal_iterator<_Iterator, _Container>& __rhs) { return __lhs.base() > __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Container> inline bool operator<=(const __normal_iterator<_IteratorL, _Container>& __lhs, const __normal_iterator<_IteratorR, _Container>& __rhs) { return __lhs.base() <= __rhs.base(); } template<typename _Iterator, typename _Container> inline bool operator<=(const __normal_iterator<_Iterator, _Container>& __lhs, const __normal_iterator<_Iterator, _Container>& __rhs) { return __lhs.base() <= __rhs.base(); } template<typename _IteratorL, typename _IteratorR, typename _Container> inline bool operator>=(const __normal_iterator<_IteratorL, _Container>& __lhs, const __normal_iterator<_IteratorR, _Container>& __rhs) { return __lhs.base() >= __rhs.base(); } template<typename _Iterator, typename _Container> inline bool operator>=(const __normal_iterator<_Iterator, _Container>& __lhs, const __normal_iterator<_Iterator, _Container>& __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 _Container> inline typename __normal_iterator<_IteratorL, _Container>::difference_type operator-(const __normal_iterator<_IteratorL, _Container>& __lhs, const __normal_iterator<_IteratorR, _Container>& __rhs) { return __lhs.base() - __rhs.base(); } template<typename _Iterator, typename _Container> inline __normal_iterator<_Iterator, _Container> operator+(typename __normal_iterator<_Iterator, _Container>::difference_type __n, const __normal_iterator<_Iterator, _Container>& __i) { return __normal_iterator<_Iterator, _Container>(__i.base() + __n); }} // namespace __gnu_cxx#endif// Local Variables:// mode:C++// End:
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