stl_map.h

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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.
                          */