图map是一种关联式容器，包含“关键字/值”对。
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// Map 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_map.h * This is an internal header file, included by other library headers. * You should not attempt to use it directly. */ #ifndef _MAP_H #define _MAP_H 1 #include <bits/concept_check.h> namespace _GLIBCXX_STD { /** * @brief A standard container made up of (key,value) pairs, which can be * retrieved based on a key, 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). * For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the * value_type is std::pair<const Key,T>. * * Maps support bidirectional iterators. * * @if maint * The private tree data is declared exactly the same way for map and * multimap; the distinction is made entirely in how the tree functions are * called (*_unique versus *_equal, same as the standard). * @endif */ template <typename _Key, typename _Tp, typename _Compare = less<_Key>, typename _Alloc = allocator<pair<const _Key, _Tp> > > class map { // concept requirements __glibcxx_class_requires(_Tp, _SGIAssignableConcept) __glibcxx_class_requires4(_Compare, bool, _Key, _Key, _BinaryFunctionConcept) public: typedef _Key key_type; typedef _Tp mapped_type; typedef pair<const _Key, _Tp> value_type; typedef _Compare key_compare; class value_compare : public binary_function<value_type, value_type, bool> { friend class map<_Key,_Tp,_Compare,_Alloc>; protected: _Compare comp; value_compare(_Compare __c) : comp(__c) { } public: bool operator()(const value_type& __x, const value_type& __y) const { return comp(__x.first, __y.first); } }; private: /// @if maint This turns a red-black tree into a [multi]map. @endif typedef _Rb_tree<key_type, value_type, _Select1st<value_type>, key_compare, _Alloc> _Rep_type; /// @if maint The actual tree structure. @endif _Rep_type _M_t; public: // many of these are specified differently in ISO, but the following are // "functionally equivalent" typedef typename _Alloc::pointer pointer; typedef typename _Alloc::const_pointer const_pointer; typedef typename _Alloc::reference reference; typedef typename _Alloc::const_reference const_reference; typedef typename _Rep_type::allocator_type allocator_type; typedef typename _Rep_type::iterator iterator; typedef typename _Rep_type::const_iterator const_iterator; typedef typename _Rep_type::size_type size_type; typedef typename _Rep_type::difference_type difference_type; typedef typename _Rep_type::reverse_iterator reverse_iterator; typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator; // [23.3.1.1] construct/copy/destroy // (get_allocator() is normally listed in this section, but seems to have // been accidentally omitted in the printed standard) /** * @brief Default constructor creates no elements. */ map() : _M_t(_Compare(), allocator_type()) { } // for some reason this was made a separate function /** * @brief Default constructor creates no elements. */ explicit map(const _Compare& __comp, const allocator_type& __a = allocator_type()) : _M_t(__comp, __a) { } /** * @brief Map copy constructor. * @param x A %map of identical element and allocator types. * * The newly-created %map uses a copy of the allocation object used * by @a x. */ map(const map& __x) : _M_t(__x._M_t) { } /** * @brief Builds a %map from a range. * @param first An input iterator. * @param last An input iterator. * * Create a %map 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 <typename _InputIterator> map(_InputIterator __first, _InputIterator __last) : _M_t(_Compare(), allocator_type()) { _M_t.insert_unique(__first, __last); } /** * @brief Builds a %map 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 %map 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 <typename _InputIterator> map(_InputIterator __first, _InputIterator __last, const _Compare& __comp, const allocator_type& __a = allocator_type()) : _M_t(__comp, __a) { _M_t.insert_unique(__first, __last); } // FIXME There is no dtor declared, but we should have something generated // by Doxygen. I don't know what tags to add to this paragraph to make // that happen: /** * The dtor only erases the elements, and note 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. */ /** * @brief Map assignment operator. * @param x A %map 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. */ map& operator=(const map& __x) { _M_t = __x._M_t; return *this; } /// Get a copy of the memory allocation object. allocator_type get_allocator() const { return _M_t.get_allocator(); } // iterators /** * Returns a read/write iterator that points to the first pair in the * %map. * Iteration is done in ascending order according to the keys. */ iterator begin() { return _M_t.begin(); } /** * Returns a read-only (constant) iterator that points to the first pair * in the %map. Iteration is done in ascending order according to the * keys. */ const_iterator begin() const { return _M_t.begin(); } /** * Returns a read/write iterator that points one past the last pair in * the %map. Iteration is done in ascending order according to the keys. */ iterator end() { return _M_t.end(); } /** * Returns a read-only (constant) iterator that points one past the last * pair in the %map. Iteration is done in ascending order according to * the keys. */ const_iterator end() const { return _M_t.end(); } /** * Returns a read/write reverse iterator that points to the last pair in * the %map. Iteration is done in descending order according to the * keys. */ reverse_iterator rbegin() { 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. */ const_reverse_iterator rbegin() const { return _M_t.rbegin(); } /** * Returns a read/write reverse iterator that points to one before the * first pair in the %map. Iteration is done in descending order * according to the keys. */ reverse_iterator rend() { return _M_t.rend(); } /** * Returns a read-only (constant) reverse iterator that points to one * before the first pair in the %map. Iteration is done in descending * order according to the keys. */ const_reverse_iterator rend() const { return _M_t.rend(); } // capacity /** Returns true if the %map is empty. (Thus begin() would equal * end().) */ bool empty() const { return _M_t.empty(); } /** Returns the size of the %map. */ size_type size() const { return _M_t.size(); } /** Returns the maximum size of the %map. */ size_type max_size() const { return _M_t.max_size(); } // [23.3.1.2] element access /** * @brief Subscript ( @c [] ) access to %map data. * @param k The key for which data should be retrieved. * @return A reference to the data of the (key,data) %pair. * * Allows for easy lookup with the subscript ( @c [] ) operator. Returns * data associated with the key specified in subscript. If the key does * not exist, a pair with that key is created using default values, which * is then returned. * * Lookup requires logarithmic time. */ mapped_type& operator[](const key_type& __k) { // concept requirements __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>) iterator __i = lower_bound(__k); // __i->first is greater than or equivalent to __k. if (__i == end() || key_comp()(__k, (*__i).first)) __i = insert(__i, value_type(__k, mapped_type())); return (*__i).second; } // modifiers /** * @brief Attempts to insert a std::pair into the %map. * @param x Pair to be inserted (see std::make_pair for easy creation of * pairs). * @return A pair, of which the first element is an iterator that points * to the possibly inserted pair, and the second is a bool that * is true if the pair was actually inserted. * * This function attempts to insert a (key, value) %pair into the %map. * A %map relies on unique keys and thus a %pair is only inserted if its * first element (the key) is not already present in the %map. * * Insertion requires logarithmic time. */ pair<iterator,bool> insert(const value_type& __x) { return _M_t.insert_unique(__x); } /** * @brief Attempts to insert a std::pair into the %map. * @param position An iterator that serves as a hint as to where the * pair should be inserted. * @param x Pair to be inserted (see std::make_pair for easy creation of * pairs). * @return An iterator that points to the element with key of @a x (may * or may not be the %pair 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) { return _M_t.insert_unique(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 <typename _InputIterator> void insert(_InputIterator __first, _InputIterator __last) { _M_t.insert_unique(__first, __last); } /** * @brief Erases an element from a %map. * @param position An iterator pointing to the element to be erased. * * This function erases an element, pointed to by the given iterator, * from a %map. 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) { _M_t.erase(__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 %map. * 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 %map. * @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 %map. * 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) { _M_t.erase(__first, __last); } /** * @brief Swaps data with another %map. * @param x A %map of the same element and allocator types. * * This exchanges the elements between two maps 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(m1,m2) will feed to this function. */ void swap(map& __x) { _M_t.swap(__x._M_t); } /** * Erases all elements in a %map. 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(); } // observers /** * Returns the key comparison object out of which the %map was * constructed. */ key_compare key_comp() const { return _M_t.key_comp(); } /** * Returns a value comparison object, built from the key comparison * object out of which the %map was constructed. */ value_compare value_comp() const { return value_compare(_M_t.key_comp()); } // [23.3.1.3] map operations /** * @brief Tries to locate an element in a %map. * @param x Key of (key, value) %pair 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 %pair. If unsuccessful it returns the * past-the-end ( @c end() ) iterator. */ iterator find(const key_type& __x) { return _M_t.find(__x); } /** * @brief Tries to locate an element in a %map. * @param x Key of (key, value) %pair to be located. * @return Read-only (constant) 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 a constant * iterator pointing to the sought after %pair. If unsuccessful it * returns the past-the-end ( @c end() ) iterator. */ const_iterator find(const key_type& __x) const { return _M_t.find(__x); } /** * @brief Finds the number of elements with given key. * @param x Key of (key, value) pairs to be located. * @return Number of elements with specified key. * * This function only makes sense for multimaps; for map 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; } /** * @brief Finds the beginning of a subsequence matching given key. * @param x Key of (key, value) pair 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); } /** * @brief Finds the beginning of a subsequence matching given key. * @param x Key of (key, value) pair to be located. * @return Read-only (constant) 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. */ 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 of (key, value) pair 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); } /** * @brief Finds the end of a subsequence matching given key. * @param x Key of (key, value) pair to be located. * @return Read-only (constant) iterator pointing to first iterator * greater than key, or end(). */ 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 of (key, value) pairs 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 multimaps. */ pair<iterator,iterator> equal_range(const key_type& __x) { return _M_t.equal_range(__x); } /** * @brief Finds a subsequence matching given key. * @param x Key of (key, value) pairs to be located. * @return Pair of read-only (constant) 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 multimaps. */ pair<const_iterator,const_iterator> equal_range(const key_type& __x) const { return _M_t.equal_range(__x); } template <typename _K1, typename _T1, typename _C1, typename _A1> friend bool operator== (const map<_K1,_T1,_C1,_A1>&, const map<_K1,_T1,_C1,_A1>&); template <typename _K1, typename _T1, typename _C1, typename _A1> friend bool operator< (const map<_K1,_T1,_C1,_A1>&, const map<_K1,_T1,_C1,_A1>&); }; /** * @brief Map equality comparison. * @param x A %map. * @param y A %map of the same type as @a x. * @return True iff the size and elements of the maps are equal. * * This is an equivalence relation. It is linear in the size of the * maps. Maps are considered equivalent if their sizes are equal, * and if corresponding elements compare equal. */ template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> inline bool operator==(const map<_Key,_Tp,_Compare,_Alloc>& __x, const map<_Key,_Tp,_Compare,_Alloc>& __y) { return __x._M_t == __y._M_t; } /** * @brief Map ordering relation. * @param x A %map. * @param y A %map 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 <typename _Key, typename _Tp, typename _Compare, typename _Alloc> inline bool operator<(const map<_Key,_Tp,_Compare,_Alloc>& __x, const map<_Key,_Tp,_Compare,_Alloc>& __y) { return __x._M_t < __y._M_t; } /// Based on operator== template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> inline bool operator!=(const map<_Key,_Tp,_Compare,_Alloc>& __x, const map<_Key,_Tp,_Compare,_Alloc>& __y) { return !(__x == __y); } /// Based on operator< template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> inline bool operator>(const map<_Key,_Tp,_Compare,_Alloc>& __x, const map<_Key,_Tp,_Compare,_Alloc>& __y) { return __y < __x; } /// Based on operator< template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> inline bool operator<=(const map<_Key,_Tp,_Compare,_Alloc>& __x, const map<_Key,_Tp,_Compare,_Alloc>& __y) { return !(__y < __x); } /// Based on operator< template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> inline bool operator>=(const map<_Key,_Tp,_Compare,_Alloc>& __x, const map<_Key,_Tp,_Compare,_Alloc>& __y) { return !(__x < __y); } /// See std::map::swap(). template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> inline void swap(map<_Key,_Tp,_Compare,_Alloc>& __x, map<_Key,_Tp,_Compare,_Alloc>& __y) { __x.swap(__y); } } // namespace std #endif /* _MAP_H */ |