text: // Map implementation -*- C++ -*-
  
  // Copyright (C) 2001-2013 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 3, 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.
  
  // Under Section 7 of GPL version 3, you are granted additional
  // permissions described in the GCC Runtime Library Exception, version
  // 3.1, as published by the Free Software Foundation.
  
  // You should have received a copy of the GNU General Public License and
  // a copy of the GCC Runtime Library Exception along with this program;
  // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  // <http://www.gnu.org/licenses/>.
  
  /*
   *
   * 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 bits/stl_map.h
   *  This is an internal header file, included by other library headers.
   *  Do not attempt to use it directly. @headername{map}
   */
  
  #ifndef _STL_MAP_H
  #define _STL_MAP_H 1
  
  #include <bits/functexcept.h>
  #include <bits/concept_check.h>
  #if __cplusplus >= 201103L
  #include <initializer_list>
  #include <tuple>
  #endif
  
  #define __EXCSTR(s) (__extension__({static const char __c[] __attribute__((section(".irom.exceptiontext,\"MS\",@progbits,1#"))) = (s); &__c[0];}))
  
  namespace std _GLIBCXX_VISIBILITY(default)
  {
  _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
  
    /**
     *  @brief A standard container made up of (key,value) pairs, which can be
     *  retrieved based on a key, in logarithmic time.
     *
     *  @ingroup associative_containers
     *
     *  @tparam _Key  Type of key objects.
     *  @tparam  _Tp  Type of mapped objects.
     *  @tparam _Compare  Comparison function object type, defaults to less<_Key>.
     *  @tparam _Alloc  Allocator type, defaults to 
     *                  allocator<pair<const _Key, _Tp>.
     *
     *  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.
     *
     *  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).
    */
    template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>,
              typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
      class map
      {
      public:
        typedef _Key                                          key_type;
        typedef _Tp                                           mapped_type;
        typedef std::pair<const _Key, _Tp>                    value_type;
        typedef _Compare                                      key_compare;
        typedef _Alloc                                        allocator_type;
  
      private:
        // concept requirements
        typedef typename _Alloc::value_type                   _Alloc_value_type;
        __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
        __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
  				_BinaryFunctionConcept)
        __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
  
      public:
        class value_compare
        : public std::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:
        /// This turns a red-black tree into a [multi]map. 
        typedef typename _Alloc::template rebind<value_type>::other 
          _Pair_alloc_type;
  
        typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
  		       key_compare, _Pair_alloc_type> _Rep_type;
  
        /// The actual tree structure.
        _Rep_type _M_t;
  
      public:
        // many of these are specified differently in ISO, but the following are
        // "functionally equivalent"
        typedef typename _Pair_alloc_type::pointer         pointer;
        typedef typename _Pair_alloc_type::const_pointer   const_pointer;
        typedef typename _Pair_alloc_type::reference       reference;
        typedef typename _Pair_alloc_type::const_reference const_reference;
        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() { }
  
        /**
         *  @brief  Creates a %map with no elements.
         *  @param  __comp  A comparison object.
         *  @param  __a  An allocator object.
         */
        explicit
        map(const _Compare& __comp,
  	  const allocator_type& __a = allocator_type())
        : _M_t(__comp, _Pair_alloc_type(__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) { }
  
  #if __cplusplus >= 201103L
        /**
         *  @brief  %Map move constructor.
         *  @param  __x  A %map of identical element and allocator types.
         *
         *  The newly-created %map contains the exact contents of @a __x.
         *  The contents of @a __x are a valid, but unspecified %map.
         */
        map(map&& __x)
        noexcept(is_nothrow_copy_constructible<_Compare>::value)
        : _M_t(std::move(__x._M_t)) { }
  
        /**
         *  @brief  Builds a %map from an initializer_list.
         *  @param  __l  An initializer_list.
         *  @param  __comp  A comparison object.
         *  @param  __a  An allocator object.
         *
         *  Create a %map consisting of copies of the elements in the
         *  initializer_list @a __l.
         *  This is linear in N if the range is already sorted, and NlogN
         *  otherwise (where N is @a __l.size()).
         */
        map(initializer_list<value_type> __l,
  	  const _Compare& __comp = _Compare(),
  	  const allocator_type& __a = allocator_type())
        : _M_t(__comp, _Pair_alloc_type(__a))
        { _M_t._M_insert_unique(__l.begin(), __l.end()); }
  #endif
  
        /**
         *  @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()
          { _M_t._M_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, _Pair_alloc_type(__a))
          { _M_t._M_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 responsibility.
         */
  
        /**
         *  @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;
        }
  
  #if __cplusplus >= 201103L
        /**
         *  @brief  %Map move assignment operator.
         *  @param  __x  A %map of identical element and allocator types.
         *
         *  The contents of @a __x are moved into this map (without copying).
         *  @a __x is a valid, but unspecified %map.
         */
        map&
        operator=(map&& __x)
        {
  	// NB: DR 1204.
  	// NB: DR 675.
  	this->clear();
  	this->swap(__x);
  	return *this;
        }
  
        /**
         *  @brief  %Map list assignment operator.
         *  @param  __l  An initializer_list.
         *
         *  This function fills a %map with copies of the elements in the
         *  initializer list @a __l.
         *
         *  Note that the assignment completely changes the %map and
         *  that the resulting %map's size is the same as the number
         *  of elements assigned.  Old data may be lost.
         */
        map&
        operator=(initializer_list<value_type> __l)
        {
  	this->clear();
  	this->insert(__l.begin(), __l.end());
  	return *this;
        }
  #endif
  
        /// Get a copy of the memory allocation object.
        allocator_type
        get_allocator() const _GLIBCXX_NOEXCEPT
        { return allocator_type(_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() _GLIBCXX_NOEXCEPT
        { 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 _GLIBCXX_NOEXCEPT
        { 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() _GLIBCXX_NOEXCEPT
        { 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 _GLIBCXX_NOEXCEPT
        { 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() _GLIBCXX_NOEXCEPT
        { 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 _GLIBCXX_NOEXCEPT
        { 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() _GLIBCXX_NOEXCEPT
        { 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 _GLIBCXX_NOEXCEPT
        { return _M_t.rend(); }
  
  #if __cplusplus >= 201103L
        /**
         *  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
        cbegin() const noexcept
        { return _M_t.begin(); }
  
        /**
         *  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
        cend() const noexcept
        { return _M_t.end(); }
  
        /**
         *  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
        crbegin() const noexcept
        { return _M_t.rbegin(); }
  
        /**
         *  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
        crend() const noexcept
        { return _M_t.rend(); }
  #endif
  
        // capacity
        /** Returns true if the %map is empty.  (Thus begin() would equal
         *  end().)
        */
        bool
        empty() const _GLIBCXX_NOEXCEPT
        { return _M_t.empty(); }
  
        /** Returns the size of the %map.  */
        size_type
        size() const _GLIBCXX_NOEXCEPT
        { return _M_t.size(); }
  
        /** Returns the maximum size of the %map.  */
        size_type
        max_size() const _GLIBCXX_NOEXCEPT
        { 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))
  #if __cplusplus >= 201103L
  	  __i = _M_t._M_emplace_hint_unique(__i, std::piecewise_construct,
  					    std::tuple<const key_type&>(__k),
  					    std::tuple<>());
  #else
            __i = insert(__i, value_type(__k, mapped_type()));
  #endif
  	return (*__i).second;
        }
  
  #if __cplusplus >= 201103L
        mapped_type&
        operator[](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 = _M_t._M_emplace_hint_unique(__i, std::piecewise_construct,
  					std::forward_as_tuple(std::move(__k)),
  					std::tuple<>());
  	return (*__i).second;
        }
  #endif
  
        // _GLIBCXX_RESOLVE_LIB_DEFECTS
        // DR 464. Suggestion for new member functions in standard containers.
        /**
         *  @brief  Access to %map data.
         *  @param  __k  The key for which data should be retrieved.
         *  @return  A reference to the data whose key is equivalent to @a __k, if
         *           such a data is present in the %map.
         *  @throw  std::out_of_range  If no such data is present.
         */
        mapped_type&
        at(const key_type& __k)
        {
  	iterator __i = lower_bound(__k);
  	if (__i == end() || key_comp()(__k, (*__i).first))
  	  __throw_out_of_range(__EXCSTR(__N("map::at")));
  	return (*__i).second;
        }
  
        const mapped_type&
        at(const key_type& __k) const
        {
  	const_iterator __i = lower_bound(__k);
  	if (__i == end() || key_comp()(__k, (*__i).first))
  	  __throw_out_of_range(__EXCSTR(__N("map::at")));
  	return (*__i).second;
        }
  
        // modifiers
  #if __cplusplus >= 201103L
        /**
         *  @brief Attempts to build and insert a std::pair into the %map.
         *
         *  @param __args  Arguments used to generate a new pair instance (see
         *	        std::piecewise_contruct for passing arguments to each
         *	        part of the pair constructor).
         *
         *  @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 build and 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.
         */
        template<typename... _Args>
  	std::pair<iterator, bool>
  	emplace(_Args&&... __args)
  	{ return _M_t._M_emplace_unique(std::forward<_Args>(__args)...); }
  
        /**
         *  @brief Attempts to build and insert a std::pair into the %map.
         *
         *  @param  __pos  An iterator that serves as a hint as to where the pair
         *                should be inserted.
         *  @param  __args  Arguments used to generate a new pair instance (see
         *	         std::piecewise_contruct for passing arguments to each
         *	         part of the pair constructor).
         *  @return An iterator that points to the element with key of the
         *          std::pair built from @a __args (may or may not be that
         *          std::pair).
         *
         *  This function is not concerned about whether the insertion took place,
         *  and thus does not return a boolean like the single-argument emplace()
         *  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++/manual/bk01pt07ch17.html
         *  for more on @a hinting.
         *
         *  Insertion requires logarithmic time (if the hint is not taken).
         */
        template<typename... _Args>
  	iterator
  	emplace_hint(const_iterator __pos, _Args&&... __args)
  	{
  	  return _M_t._M_emplace_hint_unique(__pos,
  					     std::forward<_Args>(__args)...);
  	}
  #endif
  
        /**
         *  @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.
         */
        std::pair<iterator, bool>
        insert(const value_type& __x)
        { return _M_t._M_insert_unique(__x); }
  
  #if __cplusplus >= 201103L
        template<typename _Pair, typename = typename
  	       std::enable_if<std::is_constructible<value_type,
  						    _Pair&&>::value>::type>
          std::pair<iterator, bool>
          insert(_Pair&& __x)
          { return _M_t._M_insert_unique(std::forward<_Pair>(__x)); }
  #endif
  
  #if __cplusplus >= 201103L
        /**
         *  @brief Attempts to insert a list of std::pairs into the %map.
         *  @param  __list  A std::initializer_list<value_type> of pairs to be
         *                  inserted.
         *
         *  Complexity similar to that of the range constructor.
         */
        void
        insert(std::initializer_list<value_type> __list)
        { insert(__list.begin(), __list.end()); }
  #endif
  
        /**
         *  @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++/manual/bk01pt07ch17.html
         *  for more on @a hinting.
         *
         *  Insertion requires logarithmic time (if the hint is not taken).
         */
        iterator
  #if __cplusplus >= 201103L
        insert(const_iterator __position, const value_type& __x)
  #else
        insert(iterator __position, const value_type& __x)
  #endif
        { return _M_t._M_insert_unique_(__position, __x); }
  
  #if __cplusplus >= 201103L
        template<typename _Pair, typename = typename
  	       std::enable_if<std::is_constructible<value_type,
  						    _Pair&&>::value>::type>
          iterator
          insert(const_iterator __position, _Pair&& __x)
          { return _M_t._M_insert_unique_(__position,
  					std::forward<_Pair>(__x)); }
  #endif
  
        /**
         *  @brief Template function that attempts 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._M_insert_unique(__first, __last); }
  
  #if __cplusplus >= 201103L
        // _GLIBCXX_RESOLVE_LIB_DEFECTS
        // DR 130. Associative erase should return an iterator.
        /**
         *  @brief Erases an element from a %map.
         *  @param  __position  An iterator pointing to the element to be erased.
         *  @return An iterator pointing to the element immediately following
         *          @a position prior to the element being erased. If no such 
         *          element exists, end() is returned.
         *
         *  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 responsibility.
         */
        iterator
        erase(const_iterator __position)
        { return _M_t.erase(__position); }
  
        // LWG 2059
        _GLIBCXX_ABI_TAG_CXX11
        iterator
        erase(iterator __position)
        { return _M_t.erase(__position); }
  #else
        /**
         *  @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 responsibility.
         */
        void
        erase(iterator __position)
        { _M_t.erase(__position); }
  #endif
  
        /**
         *  @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 responsibility.
         */
        size_type
        erase(const key_type& __x)
        { return _M_t.erase(__x); }
  
  #if __cplusplus >= 201103L
        // _GLIBCXX_RESOLVE_LIB_DEFECTS
        // DR 130. Associative erase should return an iterator.
        /**
         *  @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.
         *  @return The iterator @a __last.
         *
         *  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 responsibility.
         */
        iterator
        erase(const_iterator __first, const_iterator __last)
        { return _M_t.erase(__first, __last); }
  #else
        /**
         *  @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 responsibility.
         */
        void
        erase(iterator __first, iterator __last)
        { _M_t.erase(__first, __last); }
  #endif
  
        /**
         *  @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 responsibility.
         */
        void
        clear() _GLIBCXX_NOEXCEPT
        { _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.
         */
        std::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.
         */
        std::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); }
  
  _GLIBCXX_END_NAMESPACE_CONTAINER
  } // namespace std
  
  #undef __EXCSTR
  
  #endif /* _STL_MAP_H */
  