stl_multimap.h

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// Multimap 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_multimap.h
 *  This is an internal header file, included by other library headers.
 *  You should not attempt to use it directly.
 */

#ifndef _MULTIMAP_H
#define _MULTIMAP_H 1

#include <bits/concept_check.h>

namespace _GLIBCXX_STD
{
    // Forward declaration of operators < and ==, needed for friend declaration.

    template <typename _Key, typename _Tp,
             typename _Compare = less<_Key>,
             typename _Alloc = allocator<pair<const _Key, _Tp> > >
                 class multimap;

    template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
        inline bool
        operator==(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
                const multimap<_Key,_Tp,_Compare,_Alloc>& __y);

    template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
        inline bool
        operator<(const multimap<_Key,_Tp,_Compare,_Alloc>& __x,
                const multimap<_Key,_Tp,_Compare,_Alloc>& __y);

    /**
     *  @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 equivalent
     *  keys).  For a @c multimap<Key,T> the key_type is Key, the mapped_type
     *  is T, and the value_type is std::pair<const Key,T>.
     *
     *  Multimaps 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, typename _Alloc>
        class multimap
        {
            // 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 multimap<_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;

                // [23.3.2] construct/copy/destroy
                // (get_allocator() is also listed in this section)
                /**
                 *  @brief  Default constructor creates no elements.
                 */
                multimap()
                    : _M_t(_Compare(), allocator_type()) { }

                // for some reason this was made a separate function
                /**
                 *  @brief  Default constructor creates no elements.
                 */
                explicit
                    multimap(const _Compare& __comp,
                            const allocator_type& __a = allocator_type())
                    : _M_t(__comp, __a) { }

                /**
                 *  @brief  %Multimap copy constructor.
                 *  @param  x  A %multimap of identical element and allocator types.
                 *
                 *  The newly-created %multimap uses a copy of the allocation object used
                 *  by @a x.
                 */
                multimap(const multimap& __x)
                    : _M_t(__x._M_t) { }

                /**
                 *  @brief  Builds a %multimap from a range.
                 *  @param  first  An input iterator.
                 *  @param  last  An input iterator.
                 *
                 *  Create a %multimap 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>
                    multimap(_InputIterator __first, _InputIterator __last)
                    : _M_t(_Compare(), allocator_type())
                    { _M_t.insert_equal(__first, __last); }

                /**
                 *  @brief  Builds a %multimap 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 %multimap 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>
                    multimap(_InputIterator __first, _InputIterator __last,
                            const _Compare& __comp,
                            const allocator_type& __a = allocator_type())
                    : _M_t(__comp, __a)
                    { _M_t.insert_equal(__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  %Multimap assignment operator.