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// Map implementation -*- C++ -*-

// Copyright (C) 2001-2015 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

// .

/*

 *

 * 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 

#include 

#if __cplusplus >= 201103L

#include 

#include 

#endif

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.

   *

   *  Meets the requirements of a container, a

   *  reversible container, and an

   *  associative container (using unique keys).

   *  For a @c map the key_type is Key, the mapped_type is T, and the

   *  value_type is std::pair.

   *

   *  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 _Alloc = std::allocator > >

    class map

    {

    public:

      typedef _Key                                          key_type;

      typedef _Tp                                           mapped_type;

      typedef std::pair                    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

      {

	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 __gnu_cxx::__alloc_traits<_Alloc>::template

	rebind::other _Pair_alloc_type;

      typedef _Rb_tree,

		       key_compare, _Pair_alloc_type> _Rep_type;

      /// The actual tree structure.

      _Rep_type _M_t;

      typedef __gnu_cxx::__alloc_traits<_Pair_alloc_type> _Alloc_traits;

    public:

      // many of these are specified differently in ISO, but the following are

      // "functionally equivalent"

      typedef typename _Alloc_traits::pointer            pointer;

      typedef typename _Alloc_traits::const_pointer      const_pointer;

      typedef typename _Alloc_traits::reference          reference;

      typedef typename _Alloc_traits::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 also listed in this section)

      /**

       *  @brief  Default constructor creates no elements.

       */

      map()

#if __cplusplus >= 201103L

      noexcept(is_nothrow_default_constructible::value)

#endif

      : _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 __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()); }

      /// Allocator-extended default constructor.

      explicit

      map(const allocator_type& __a)

      : _M_t(_Compare(), _Pair_alloc_type(__a)) { }

      /// Allocator-extended copy constructor.

      map(const map& __m, const allocator_type& __a)

      : _M_t(__m._M_t, _Pair_alloc_type(__a)) { }

      /// Allocator-extended move constructor.

      map(map&& __m, const allocator_type& __a)

      noexcept(is_nothrow_copy_constructible<_Compare>::value

	       && _Alloc_traits::_S_always_equal())

      : _M_t(std::move(__m._M_t), _Pair_alloc_type(__a)) { }

      /// Allocator-extended initialier-list constructor.

      map(initializer_list __l, const allocator_type& __a)

      : _M_t(_Compare(), _Pair_alloc_type(__a))

      { _M_t._M_insert_unique(__l.begin(), __l.end()); }

      /// Allocator-extended range constructor.

      template

        map(_InputIterator __first, _InputIterator __last,

	    const allocator_type& __a)

	: _M_t(_Compare(), _Pair_alloc_type(__a))

        { _M_t._M_insert_unique(__first, __last); }

#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

        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

        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

      /// Move assignment operator.

      map&

      operator=(map&&) = default;

      /**

       *  @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 __l)

      {

	_M_t._M_assign_unique(__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)

	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(__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)

	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(__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(__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

	std::pair

	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

       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints

       *  for more on @a hinting.

       *

       *  Insertion requires logarithmic time (if the hint is not taken).

       */

      template

	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

      insert(const value_type& __x)

      { return _M_t._M_insert_unique(__x); }

#if __cplusplus >= 201103L

      template

	       std::enable_if

						    _Pair&&>::value>::type>

        std::pair

        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 of pairs to be

       *                  inserted.

       *

       *  Complexity similar to that of the range constructor.

       */

      void

      insert(std::initializer_list __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

       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints

       *  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

	       std::enable_if

						    _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

        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)

#if __cplusplus >= 201103L

      noexcept(_Alloc_traits::_S_nothrow_swap())

#endif

      { _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); }

#if __cplusplus > 201103L

      template

	auto

	find(const _Kt& __x) -> decltype(_M_t._M_find_tr(__x))

	{ return _M_t._M_find_tr(__x); }

#endif

      //@}

      //@{

      /**

       *  @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); }

#if __cplusplus > 201103L

      template

	auto

	find(const _Kt& __x) const -> decltype(_M_t._M_find_tr(__x))

	{ return _M_t._M_find_tr(__x); }

#endif

      //@}

      //@{

      /**

       *  @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; }

#if __cplusplus > 201103L

      template

	auto

	count(const _Kt& __x) const -> decltype(_M_t._M_count_tr(__x))

	{ return _M_t._M_find_tr(__x) == _M_t.end() ? 0 : 1; }

#endif

      //@}

      //@{

      /**

       *  @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); }

#if __cplusplus > 201103L

      template

	auto

	lower_bound(const _Kt& __x)

	-> decltype(_M_t._M_lower_bound_tr(__x))

	{ return _M_t._M_lower_bound_tr(__x); }

#endif

      //@}

      //@{

      /**

       *  @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); }

#if __cplusplus > 201103L

      template

	auto

	lower_bound(const _Kt& __x) const

	-> decltype(_M_t._M_lower_bound_tr(__x))

	{ return _M_t._M_lower_bound_tr(__x); }

#endif

      //@}

      //@{

      /**

       *  @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); }

#if __cplusplus > 201103L

      template

	auto

	upper_bound(const _Kt& __x)

	-> decltype(_M_t._M_upper_bound_tr(__x))

	{ return _M_t._M_upper_bound_tr(__x); }

#endif

      //@}

      //@{

      /**

       *  @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); }

#if __cplusplus > 201103L

      template

	auto

	upper_bound(const _Kt& __x) const

	-> decltype(_M_t._M_upper_bound_tr(__x))

	{ return _M_t._M_upper_bound_tr(__x); }

#endif

      //@}

      //@{

      /**

       *  @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

      equal_range(const key_type& __x)

      { return _M_t.equal_range(__x); }

#if __cplusplus > 201103L

      template

	auto

	equal_range(const _Kt& __x)

	-> decltype(_M_t._M_equal_range_tr(__x))

	{ return _M_t._M_equal_range_tr(__x); }

#endif

      //@}

      //@{

      /**

       *  @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

      equal_range(const key_type& __x) const

      { return _M_t.equal_range(__x); }

#if __cplusplus > 201103L

      template

	auto

	equal_range(const _Kt& __x) const

	-> decltype(_M_t._M_equal_range_tr(__x))

	{ return _M_t._M_equal_range_tr(__x); }

#endif

      //@}

      template

        friend bool

        operator==(const map<_K1, _T1, _C1, _A1>&,

		   const map<_K1, _T1, _C1, _A1>&);

      template

        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

    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

    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

    inline bool

    operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x,

               const map<_Key, _Tp, _Compare, _Alloc>& __y)

    { return !(__x == __y); }

  /// Based on operator<

  template

    inline bool

    operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x,

              const map<_Key, _Tp, _Compare, _Alloc>& __y)

    { return __y < __x; }

  /// Based on operator<

  template

    inline bool

    operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x,

               const map<_Key, _Tp, _Compare, _Alloc>& __y)

    { return !(__y < __x); }

  /// Based on operator<

  template

    inline bool

    operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,

               const map<_Key, _Tp, _Compare, _Alloc>& __y)

    { return !(__x < __y); }