set容器是关联容器，跟数学中的集合是一样的（没有重复元素）。
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// Set implementation -*- C++ -*- // Copyright (C) 2001, 2002, 2004 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 2, 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. // You should have received a copy of the GNU General Public License along // with this library; see the file COPYING. If not, write to the Free // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, // USA. // As a special exception, you may use this file as part of a free software // library without restriction. Specifically, if other files instantiate // templates or use macros or inline functions from this file, or you compile // this file and link it with other files to produce an executable, this // file does not by itself cause the resulting executable to be covered by // the GNU General Public License. This exception does not however // invalidate any other reasons why the executable file might be covered by // the GNU General Public License. /* * * Copyright (c) 1994 * Hewlett-Packard Company * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Hewlett-Packard Company makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. * * * Copyright (c) 1996,1997 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Silicon Graphics makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. */ /** @file stl_set.h * This is an internal header file, included by other library headers. * You should not attempt to use it directly. */ #ifndef _SET_H #define _SET_H 1 #include <bits/concept_check.h> namespace _GLIBCXX_STD { // Forward declarations of operators < and ==, needed for friend declaration. template<class _Key, class _Compare = less<_Key>, class _Alloc = allocator<_Key> > class set; template<class _Key, class _Compare, class _Alloc> inline bool operator==(const set<_Key,_Compare,_Alloc>& __x, const set<_Key,_Compare,_Alloc>& __y); template<class _Key, class _Compare, class _Alloc> inline bool operator<(const set<_Key,_Compare,_Alloc>& __x, const set<_Key,_Compare,_Alloc>& __y); /** * @brief A standard container made up of unique keys, which can be * retrieved in logarithmic time. * * @ingroup Containers * @ingroup Assoc_containers * * Meets the requirements of a <a href="tables.html#65">container</a>, a * <a href="tables.html#66">reversible container</a>, and an * <a href="tables.html#69">associative container</a> (using unique keys). * * Sets support bidirectional iterators. * * @param Key Type of key objects. * @param Compare Comparison function object type, defaults to less<Key>. * @param Alloc Allocator type, defaults to allocator<Key>. * * @if maint * The private tree data is declared exactly the same way for set and * multiset; the distinction is made entirely in how the tree functions are * called (*_unique versus *_equal, same as the standard). * @endif */ template<class _Key, class _Compare, class _Alloc> class set { // concept requirements __glibcxx_class_requires(_Key, _SGIAssignableConcept) __glibcxx_class_requires4(_Compare, bool, _Key, _Key, _BinaryFunctionConcept) public: // typedefs: //@{ /// Public typedefs. typedef _Key key_type; typedef _Key value_type; typedef _Compare key_compare; typedef _Compare value_compare; //@} private: typedef _Rb_tree<key_type, value_type, _Identity<value_type>, key_compare, _Alloc> _Rep_type; _Rep_type _M_t; // red-black tree representing set public: //@{ /// Iterator-related typedefs. typedef typename _Alloc::pointer pointer; typedef typename _Alloc::const_pointer const_pointer; typedef typename _Alloc::reference reference; typedef typename _Alloc::const_reference const_reference; // _GLIBCXX_RESOLVE_LIB_DEFECTS // DR 103. set::iterator is required to be modifiable, // but this allows modification of keys. typedef typename _Rep_type::const_iterator iterator; typedef typename _Rep_type::const_iterator const_iterator; typedef typename _Rep_type::const_reverse_iterator reverse_iterator; typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator; typedef typename _Rep_type::size_type size_type; typedef typename _Rep_type::difference_type difference_type; typedef typename _Rep_type::allocator_type allocator_type; //@} // allocation/deallocation /// Default constructor creates no elements. set() : _M_t(_Compare(), allocator_type()) {} /** * @brief Default constructor creates no elements. * * @param comp Comparator to use. * @param a Allocator to use. */ explicit set(const _Compare& __comp, const allocator_type& __a = allocator_type()) : _M_t(__comp, __a) {} /** * @brief Builds a %set from a range. * @param first An input iterator. * @param last An input iterator. * * Create a %set consisting of copies of the elements from [first,last). * This is linear in N if the range is already sorted, and NlogN * otherwise (where N is distance(first,last)). */ template<class _InputIterator> set(_InputIterator __first, _InputIterator __last) : _M_t(_Compare(), allocator_type()) { _M_t.insert_unique(__first, __last); } /** * @brief Builds a %set from a range. * @param first An input iterator. * @param last An input iterator. * @param comp A comparison functor. * @param a An allocator object. * * Create a %set consisting of copies of the elements from [first,last). * This is linear in N if the range is already sorted, and NlogN * otherwise (where N is distance(first,last)). */ template<class _InputIterator> set(_InputIterator __first, _InputIterator __last, const _Compare& __comp, const allocator_type& __a = allocator_type()) : _M_t(__comp, __a) { _M_t.insert_unique(__first, __last); } /** * @brief Set copy constructor. * @param x A %set of identical element and allocator types. * * The newly-created %set uses a copy of the allocation object used * by @a x. */ set(const set<_Key,_Compare,_Alloc>& __x) : _M_t(__x._M_t) { } /** * @brief Set assignment operator. * @param x A %set of identical element and allocator types. * * All the elements of @a x are copied, but unlike the copy constructor, * the allocator object is not copied. */ set<_Key,_Compare,_Alloc>& operator=(const set<_Key, _Compare, _Alloc>& __x) { _M_t = __x._M_t; return *this; } // accessors: /// Returns the comparison object with which the %set was constructed. key_compare key_comp() const { return _M_t.key_comp(); } /// Returns the comparison object with which the %set was constructed. value_compare value_comp() const { return _M_t.key_comp(); } /// Returns the allocator object with which the %set was constructed. allocator_type get_allocator() const { return _M_t.get_allocator(); } /** * Returns a read/write iterator that points to the first element in the * %set. Iteration is done in ascending order according to the keys. */ iterator begin() const { return _M_t.begin(); } /** * Returns a read/write iterator that points one past the last element in * the %set. Iteration is done in ascending order according to the keys. */ iterator end() const { return _M_t.end(); } /** * Returns a read/write reverse iterator that points to the last element * in the %set. Iteration is done in descending order according to the * keys. */ reverse_iterator rbegin() const { return _M_t.rbegin(); } /** * Returns a read-only (constant) reverse iterator that points to the * last pair in the %map. Iteration is done in descending order * according to the keys. */ reverse_iterator rend() const { return _M_t.rend(); } /// Returns true if the %set is empty. bool empty() const { return _M_t.empty(); } /// Returns the size of the %set. size_type size() const { return _M_t.size(); } /// Returns the maximum size of the %set. size_type max_size() const { return _M_t.max_size(); } /** * @brief Swaps data with another %set. * @param x A %set of the same element and allocator types. * * This exchanges the elements between two sets in constant time. * (It is only swapping a pointer, an integer, and an instance of * the @c Compare type (which itself is often stateless and empty), so it * should be quite fast.) * Note that the global std::swap() function is specialized such that * std::swap(s1,s2) will feed to this function. */ void swap(set<_Key,_Compare,_Alloc>& __x) { _M_t.swap(__x._M_t); } // insert/erase /** * @brief Attempts to insert an element into the %set. * @param x Element to be inserted. * @return A pair, of which the first element is an iterator that points * to the possibly inserted element, and the second is a bool * that is true if the element was actually inserted. * * This function attempts to insert an element into the %set. A %set * relies on unique keys and thus an element is only inserted if it is * not already present in the %set. * * Insertion requires logarithmic time. */ pair<iterator,bool> insert(const value_type& __x) { pair<typename _Rep_type::iterator, bool> __p = _M_t.insert_unique(__x); return pair<iterator, bool>(__p.first, __p.second); } /** * @brief Attempts to insert an element into the %set. * @param position An iterator that serves as a hint as to where the * element should be inserted. * @param x Element to be inserted. * @return An iterator that points to the element with key of @a x (may * or may not be the element passed in). * * This function is not concerned about whether the insertion took place, * and thus does not return a boolean like the single-argument insert() * does. Note that the first parameter is only a hint and can * potentially improve the performance of the insertion process. A bad * hint would cause no gains in efficiency. * * See http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html#4 * for more on "hinting". * * Insertion requires logarithmic time (if the hint is not taken). */ iterator insert(iterator __position, const value_type& __x) { typedef typename _Rep_type::iterator _Rep_iterator; return _M_t.insert_unique((_Rep_iterator&)__position, __x); } /** * @brief A template function that attemps to insert a range of elements. * @param first Iterator pointing to the start of the range to be * inserted. * @param last Iterator pointing to the end of the range. * * Complexity similar to that of the range constructor. */ template<class _InputIterator> void insert(_InputIterator __first, _InputIterator __last) { _M_t.insert_unique(__first, __last); } /** * @brief Erases an element from a %set. * @param position An iterator pointing to the element to be erased. * * This function erases an element, pointed to by the given iterator, * from a %set. Note that this function only erases the element, and * that if the element is itself a pointer, the pointed-to memory is not * touched in any way. Managing the pointer is the user's responsibilty. */ void erase(iterator __position) { typedef typename _Rep_type::iterator _Rep_iterator; _M_t.erase((_Rep_iterator&)__position); } /** * @brief Erases elements according to the provided key. * @param x Key of element to be erased. * @return The number of elements erased. * * This function erases all the elements located by the given key from * a %set. * Note that this function only erases the element, and that if * the element is itself a pointer, the pointed-to memory is not touched * in any way. Managing the pointer is the user's responsibilty. */ size_type erase(const key_type& __x) { return _M_t.erase(__x); } /** * @brief Erases a [first,last) range of elements from a %set. * @param first Iterator pointing to the start of the range to be * erased. * @param last Iterator pointing to the end of the range to be erased. * * This function erases a sequence of elements from a %set. * Note that this function only erases the element, and that if * the element is itself a pointer, the pointed-to memory is not touched * in any way. Managing the pointer is the user's responsibilty. */ void erase(iterator __first, iterator __last) { typedef typename _Rep_type::iterator _Rep_iterator; _M_t.erase((_Rep_iterator&)__first, (_Rep_iterator&)__last); } /** * Erases all elements in a %set. Note that this function only erases * the elements, and that if the elements themselves are pointers, the * pointed-to memory is not touched in any way. Managing the pointer is * the user's responsibilty. */ void clear() { _M_t.clear(); } // set operations: /** * @brief Finds the number of elements. * @param x Element to located. * @return Number of elements with specified key. * * This function only makes sense for multisets; for set the result will * either be 0 (not present) or 1 (present). */ size_type count(const key_type& __x) const { return _M_t.find(__x) == _M_t.end() ? 0 : 1; } // _GLIBCXX_RESOLVE_LIB_DEFECTS // 214. set::find() missing const overload //@{ /** * @brief Tries to locate an element in a %set. * @param x Element to be located. * @return Iterator pointing to sought-after element, or end() if not * found. * * This function takes a key and tries to locate the element with which * the key matches. If successful the function returns an iterator * pointing to the sought after element. If unsuccessful it returns the * past-the-end ( @c end() ) iterator. */ iterator find(const key_type& __x) { return _M_t.find(__x); } const_iterator find(const key_type& __x) const { return _M_t.find(__x); } //@} //@{ /** * @brief Finds the beginning of a subsequence matching given key. * @param x Key to be located. * @return Iterator pointing to first element equal to or greater * than key, or end(). * * This function returns the first element of a subsequence of elements * that matches the given key. If unsuccessful it returns an iterator * pointing to the first element that has a greater value than given key * or end() if no such element exists. */ iterator lower_bound(const key_type& __x) { return _M_t.lower_bound(__x); } const_iterator lower_bound(const key_type& __x) const { return _M_t.lower_bound(__x); } //@} //@{ /** * @brief Finds the end of a subsequence matching given key. * @param x Key to be located. * @return Iterator pointing to the first element * greater than key, or end(). */ iterator upper_bound(const key_type& __x) { return _M_t.upper_bound(__x); } const_iterator upper_bound(const key_type& __x) const { return _M_t.upper_bound(__x); } //@} //@{ /** * @brief Finds a subsequence matching given key. * @param x Key to be located. * @return Pair of iterators that possibly points to the subsequence * matching given key. * * This function is equivalent to * @code * std::make_pair(c.lower_bound(val), * c.upper_bound(val)) * @endcode * (but is faster than making the calls separately). * * This function probably only makes sense for multisets. */ pair<iterator,iterator> equal_range(const key_type& __x) { return _M_t.equal_range(__x); } pair<const_iterator,const_iterator> equal_range(const key_type& __x) const { return _M_t.equal_range(__x); } //@} template<class _K1, class _C1, class _A1> friend bool operator== (const set<_K1,_C1,_A1>&, const set<_K1,_C1,_A1>&); template<class _K1, class _C1, class _A1> friend bool operator< (const set<_K1,_C1,_A1>&, const set<_K1,_C1,_A1>&); }; /** * @brief Set equality comparison. * @param x A %set. * @param y A %set of the same type as @a x. * @return True iff the size and elements of the sets are equal. * * This is an equivalence relation. It is linear in the size of the sets. * Sets are considered equivalent if their sizes are equal, and if * corresponding elements compare equal. */ template<class _Key, class _Compare, class _Alloc> inline bool operator==(const set<_Key,_Compare,_Alloc>& __x, const set<_Key,_Compare,_Alloc>& __y) { return __x._M_t == __y._M_t; } /** * @brief Set ordering relation. * @param x A %set. * @param y A %set of the same type as @a x. * @return True iff @a x is lexicographically less than @a y. * * This is a total ordering relation. It is linear in the size of the * maps. The elements must be comparable with @c <. * * See std::lexicographical_compare() for how the determination is made. */ template<class _Key, class _Compare, class _Alloc> inline bool operator<(const set<_Key,_Compare,_Alloc>& __x, const set<_Key,_Compare,_Alloc>& __y) { return __x._M_t < __y._M_t; } /// Returns !(x == y). template<class _Key, class _Compare, class _Alloc> inline bool operator!=(const set<_Key,_Compare,_Alloc>& __x, const set<_Key,_Compare,_Alloc>& __y) { return !(__x == __y); } /// Returns y < x. template<class _Key, class _Compare, class _Alloc> inline bool operator>(const set<_Key,_Compare,_Alloc>& __x, const set<_Key,_Compare,_Alloc>& __y) { return __y < __x; } /// Returns !(y < x) template<class _Key, class _Compare, class _Alloc> inline bool operator<=(const set<_Key,_Compare,_Alloc>& __x, const set<_Key,_Compare,_Alloc>& __y) { return !(__y < __x); } /// Returns !(x < y) template<class _Key, class _Compare, class _Alloc> inline bool operator>=(const set<_Key,_Compare,_Alloc>& __x, const set<_Key,_Compare,_Alloc>& __y) { return !(__x < __y); } /// See std::set::swap(). template<class _Key, class _Compare, class _Alloc> inline void swap(set<_Key,_Compare,_Alloc>& __x, set<_Key,_Compare,_Alloc>& __y) { __x.swap(__y); } } // namespace std #endif /* _SET_H */ |