text: //////////////////////////////////////////////////////////////////////////////
  //
  // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
  // Software License, Version 1.0. (See accompanying file
  // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  // See http://www.boost.org/libs/container for documentation.
  //
  //////////////////////////////////////////////////////////////////////////////
  
  #ifndef BOOST_CONTAINER_FLAT_MAP_HPP
  #define BOOST_CONTAINER_FLAT_MAP_HPP
  
  #if (defined _MSC_VER) && (_MSC_VER >= 1200)
  #  pragma once
  #endif
  
  #include <boost/container/detail/config_begin.hpp>
  #include <boost/container/detail/workaround.hpp>
  
  #include <boost/container/container_fwd.hpp>
  #include <utility>
  #include <functional>
  #include <memory>
  #include <stdexcept>
  #include <boost/container/detail/flat_tree.hpp>
  #include <boost/type_traits/has_trivial_destructor.hpp>
  #include <boost/container/detail/mpl.hpp>
  #include <boost/container/allocator_traits.hpp>
  #include <boost/move/utility.hpp>
  #include <boost/move/detail/move_helpers.hpp>
  
  namespace boost {
  namespace container {
  
  /// @cond
  // Forward declarations of operators == and <, needed for friend declarations.
  template <class Key, class T, class Compare, class Allocator>
  class flat_map;
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator==(const flat_map<Key,T,Compare,Allocator>& x,
                         const flat_map<Key,T,Compare,Allocator>& y);
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator<(const flat_map<Key,T,Compare,Allocator>& x,
                        const flat_map<Key,T,Compare,Allocator>& y);
  
  namespace container_detail{
  
  template<class D, class S>
  static D &force(const S &s)
  {  return *const_cast<D*>((reinterpret_cast<const D*>(&s))); }
  
  template<class D, class S>
  static D force_copy(S s)
  {
     D *vp = reinterpret_cast<D *>(&s);
     return D(*vp);
  }
  
  }  //namespace container_detail{
  
  
  /// @endcond
  
  //! A flat_map is a kind of associative container that supports unique keys (contains at
  //! most one of each key value) and provides for fast retrieval of values of another
  //! type T based on the keys. The flat_map class supports random-access iterators.
  //!
  //! A flat_map satisfies all of the requirements of a container and of a reversible
  //! container and of an associative container. A flat_map also provides
  //! most operations described for unique keys. For a
  //! flat_map<Key,T> the key_type is Key and the value_type is std::pair<Key,T>
  //! (unlike std::map<Key, T> which value_type is std::pair<<b>const</b> Key, T>).
  //!
  //! Compare is the ordering function for Keys (e.g. <i>std::less<Key></i>).
  //!
  //! Allocator is the allocator to allocate the value_types
  //! (e.g. <i>allocator< std::pair<Key, T> ></i>).
  //!
  //! flat_map is similar to std::map but it's implemented like an ordered vector.
  //! This means that inserting a new element into a flat_map invalidates
  //! previous iterators and references
  //!
  //! Erasing an element of a flat_map invalidates iterators and references
  //! pointing to elements that come after (their keys are bigger) the erased element.
  #ifdef BOOST_CONTAINER_DOXYGEN_INVOKED
  template <class Key, class T, class Compare = std::less<Key>, class Allocator = std::allocator< std::pair< Key, T> > >
  #else
  template <class Key, class T, class Compare, class Allocator>
  #endif
  class flat_map
  {
     /// @cond
     private:
     BOOST_COPYABLE_AND_MOVABLE(flat_map)
     //This is the tree that we should store if pair was movable
     typedef container_detail::flat_tree<Key,
                             std::pair<Key, T>,
                             container_detail::select1st< std::pair<Key, T> >,
                             Compare,
                             Allocator> tree_t;
  
     //This is the real tree stored here. It's based on a movable pair
     typedef container_detail::flat_tree<Key,
                             container_detail::pair<Key, T>,
                             container_detail::select1st<container_detail::pair<Key, T> >,
                             Compare,
                             typename allocator_traits<Allocator>::template portable_rebind_alloc
                                <container_detail::pair<Key, T> >::type> impl_tree_t;
     impl_tree_t m_flat_tree;  // flat tree representing flat_map
  
     typedef typename impl_tree_t::value_type              impl_value_type;
     typedef typename impl_tree_t::const_iterator          impl_const_iterator;
     typedef typename impl_tree_t::allocator_type          impl_allocator_type;
     typedef container_detail::flat_tree_value_compare
        < Compare
        , container_detail::select1st< std::pair<Key, T> >
        , std::pair<Key, T> >                                                         value_compare_impl;
     typedef typename container_detail::get_flat_tree_iterators
           <typename allocator_traits<Allocator>::pointer>::iterator                  iterator_impl;
     typedef typename container_detail::get_flat_tree_iterators
        <typename allocator_traits<Allocator>::pointer>::const_iterator               const_iterator_impl;
     typedef typename container_detail::get_flat_tree_iterators
           <typename allocator_traits<Allocator>::pointer>::reverse_iterator          reverse_iterator_impl;
     typedef typename container_detail::get_flat_tree_iterators
           <typename allocator_traits<Allocator>::pointer>::const_reverse_iterator    const_reverse_iterator_impl;
     /// @endcond
  
     public:
  
     //////////////////////////////////////////////
     //
     //                    types
     //
     //////////////////////////////////////////////
     typedef Key                                                                      key_type;
     typedef T                                                                        mapped_type;
     typedef std::pair<Key, T>                                                        value_type;
     typedef typename boost::container::allocator_traits<Allocator>::pointer          pointer;
     typedef typename boost::container::allocator_traits<Allocator>::const_pointer    const_pointer;
     typedef typename boost::container::allocator_traits<Allocator>::reference        reference;
     typedef typename boost::container::allocator_traits<Allocator>::const_reference  const_reference;
     typedef typename boost::container::allocator_traits<Allocator>::size_type        size_type;
     typedef typename boost::container::allocator_traits<Allocator>::difference_type  difference_type;
     typedef Allocator                                                                allocator_type;
     typedef BOOST_CONTAINER_IMPDEF(Allocator)                                        stored_allocator_type;
     typedef BOOST_CONTAINER_IMPDEF(value_compare_impl)                               value_compare;
     typedef Compare                                                                  key_compare;
     typedef BOOST_CONTAINER_IMPDEF(iterator_impl)                                    iterator;
     typedef BOOST_CONTAINER_IMPDEF(const_iterator_impl)                              const_iterator;
     typedef BOOST_CONTAINER_IMPDEF(reverse_iterator_impl)                            reverse_iterator;
     typedef BOOST_CONTAINER_IMPDEF(const_reverse_iterator_impl)                      const_reverse_iterator;
     typedef BOOST_CONTAINER_IMPDEF(impl_value_type)                                  movable_value_type;
  
     public:
     //////////////////////////////////////////////
     //
     //          construct/copy/destroy
     //
     //////////////////////////////////////////////
  
     //! <b>Effects</b>: Default constructs an empty flat_map.
     //!
     //! <b>Complexity</b>: Constant.
     flat_map()
        : m_flat_tree() {}
  
     //! <b>Effects</b>: Constructs an empty flat_map using the specified
     //! comparison object and allocator.
     //!
     //! <b>Complexity</b>: Constant.
     explicit flat_map(const Compare& comp, const allocator_type& a = allocator_type())
        : m_flat_tree(comp, container_detail::force<impl_allocator_type>(a)) {}
  
     //! <b>Effects</b>: Constructs an empty flat_map using the specified comparison object and
     //! allocator, and inserts elements from the range [first ,last ).
     //!
     //! <b>Complexity</b>: Linear in N if the range [first ,last ) is already sorted using
     //! comp and otherwise N logN, where N is last - first.
     template <class InputIterator>
     flat_map(InputIterator first, InputIterator last, const Compare& comp = Compare(),
           const allocator_type& a = allocator_type())
        : m_flat_tree(true, first, last, comp, container_detail::force<impl_allocator_type>(a))
     {}
  
     //! <b>Effects</b>: Constructs an empty flat_map using the specified comparison object and
     //! allocator, and inserts elements from the ordered unique range [first ,last). This function
     //! is more efficient than the normal range creation for ordered ranges.
     //!
     //! <b>Requires</b>: [first ,last) must be ordered according to the predicate and must be
     //! unique values.
     //!
     //! <b>Complexity</b>: Linear in N.
     //!
     //! <b>Note</b>: Non-standard extension.
     template <class InputIterator>
     flat_map( ordered_unique_range_t, InputIterator first, InputIterator last
             , const Compare& comp = Compare(), const allocator_type& a = allocator_type())
        : m_flat_tree(ordered_range, first, last, comp, a)
     {}
  
     //! <b>Effects</b>: Copy constructs a flat_map.
     //!
     //! <b>Complexity</b>: Linear in x.size().
     flat_map(const flat_map& x)
        : m_flat_tree(x.m_flat_tree) {}
  
     //! <b>Effects</b>: Move constructs a flat_map.
     //!   Constructs *this using x's resources.
     //!
     //! <b>Complexity</b>: Constant.
     //!
     //! <b>Postcondition</b>: x is emptied.
     flat_map(BOOST_RV_REF(flat_map) x)
        : m_flat_tree(boost::move(x.m_flat_tree))
     {}
  
     //! <b>Effects</b>: Copy constructs a flat_map using the specified allocator.
     //!
     //! <b>Complexity</b>: Linear in x.size().
     flat_map(const flat_map& x, const allocator_type &a)
        : m_flat_tree(x.m_flat_tree, a)
     {}
  
     //! <b>Effects</b>: Move constructs a flat_map using the specified allocator.
     //!   Constructs *this using x's resources.
     //!
     //! <b>Complexity</b>: Constant if x.get_allocator() == a, linear otherwise.
     flat_map(BOOST_RV_REF(flat_map) x, const allocator_type &a)
        : m_flat_tree(boost::move(x.m_flat_tree), a)
     {}
  
     //! <b>Effects</b>: Makes *this a copy of x.
     //!
     //! <b>Complexity</b>: Linear in x.size().
     flat_map& operator=(BOOST_COPY_ASSIGN_REF(flat_map) x)
     {  m_flat_tree = x.m_flat_tree;   return *this;  }
  
     //! <b>Effects</b>: Move constructs a flat_map.
     //!   Constructs *this using x's resources.
     //!
     //! <b>Complexity</b>: Construct.
     //!
     //! <b>Postcondition</b>: x is emptied.
     flat_map& operator=(BOOST_RV_REF(flat_map) mx)
     {  m_flat_tree = boost::move(mx.m_flat_tree);   return *this;  }
  
     //! <b>Effects</b>: Returns a copy of the Allocator that
     //!   was passed to the object's constructor.
     //!
     //! <b>Complexity</b>: Constant.
     allocator_type get_allocator() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<allocator_type>(m_flat_tree.get_allocator()); }
  
     //! <b>Effects</b>: Returns a reference to the internal allocator.
     //!
     //! <b>Throws</b>: Nothing
     //!
     //! <b>Complexity</b>: Constant.
     //!
     //! <b>Note</b>: Non-standard extension.
     stored_allocator_type &get_stored_allocator() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force<stored_allocator_type>(m_flat_tree.get_stored_allocator()); }
  
     //! <b>Effects</b>: Returns a reference to the internal allocator.
     //!
     //! <b>Throws</b>: Nothing
     //!
     //! <b>Complexity</b>: Constant.
     //!
     //! <b>Note</b>: Non-standard extension.
     const stored_allocator_type &get_stored_allocator() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force<stored_allocator_type>(m_flat_tree.get_stored_allocator()); }
  
     //////////////////////////////////////////////
     //
     //                iterators
     //
     //////////////////////////////////////////////
  
     //! <b>Effects</b>: Returns an iterator to the first element contained in the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     iterator begin() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<iterator>(m_flat_tree.begin()); }
  
     //! <b>Effects</b>: Returns a const_iterator to the first element contained in the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_iterator begin() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_iterator>(m_flat_tree.begin()); }
  
     //! <b>Effects</b>: Returns an iterator to the end of the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     iterator end() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<iterator>(m_flat_tree.end()); }
  
     //! <b>Effects</b>: Returns a const_iterator to the end of the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_iterator end() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_iterator>(m_flat_tree.end()); }
  
     //! <b>Effects</b>: Returns a reverse_iterator pointing to the beginning
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     reverse_iterator rbegin() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<reverse_iterator>(m_flat_tree.rbegin()); }
  
     //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the beginning
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_reverse_iterator rbegin() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_reverse_iterator>(m_flat_tree.rbegin()); }
  
     //! <b>Effects</b>: Returns a reverse_iterator pointing to the end
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     reverse_iterator rend() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<reverse_iterator>(m_flat_tree.rend()); }
  
     //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the end
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_reverse_iterator rend() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_reverse_iterator>(m_flat_tree.rend()); }
  
     //! <b>Effects</b>: Returns a const_iterator to the first element contained in the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_iterator cbegin() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_iterator>(m_flat_tree.cbegin()); }
  
     //! <b>Effects</b>: Returns a const_iterator to the end of the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_iterator cend() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_iterator>(m_flat_tree.cend()); }
  
     //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the beginning
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_reverse_iterator crbegin() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_reverse_iterator>(m_flat_tree.crbegin()); }
  
     //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the end
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_reverse_iterator crend() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_reverse_iterator>(m_flat_tree.crend()); }
  
     //////////////////////////////////////////////
     //
     //                capacity
     //
     //////////////////////////////////////////////
  
     //! <b>Effects</b>: Returns true if the container contains no elements.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     bool empty() const BOOST_CONTAINER_NOEXCEPT
        { return m_flat_tree.empty(); }
  
     //! <b>Effects</b>: Returns the number of the elements contained in the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     size_type size() const BOOST_CONTAINER_NOEXCEPT
        { return m_flat_tree.size(); }
  
     //! <b>Effects</b>: Returns the largest possible size of the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     size_type max_size() const BOOST_CONTAINER_NOEXCEPT
        { return m_flat_tree.max_size(); }
  
     //! <b>Effects</b>: Number of elements for which memory has been allocated.
     //!   capacity() is always greater than or equal to size().
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     size_type capacity() const BOOST_CONTAINER_NOEXCEPT        
        { return m_flat_tree.capacity(); }
  
     //! <b>Effects</b>: If n is less than or equal to capacity(), this call has no
     //!   effect. Otherwise, it is a request for allocation of additional memory.
     //!   If the request is successful, then capacity() is greater than or equal to
     //!   n; otherwise, capacity() is unchanged. In either case, size() is unchanged.
     //!
     //! <b>Throws</b>: If memory allocation allocation throws or T's copy constructor throws.
     //!
     //! <b>Note</b>: If capacity() is less than "cnt", iterators and references to
     //!   to values might be invalidated.
     void reserve(size_type cnt)      
        { m_flat_tree.reserve(cnt);   }
  
     //! <b>Effects</b>: Tries to deallocate the excess of memory created
     //    with previous allocations. The size of the vector is unchanged
     //!
     //! <b>Throws</b>: If memory allocation throws, or T's copy constructor throws.
     //!
     //! <b>Complexity</b>: Linear to size().
     void shrink_to_fit()
        { m_flat_tree.shrink_to_fit(); }
  
     //////////////////////////////////////////////
     //
     //               element access
     //
     //////////////////////////////////////////////
  
     #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
     //! Effects: If there is no key equivalent to x in the flat_map, inserts
     //!   value_type(x, T()) into the flat_map.
     //!
     //! Returns: Allocator reference to the mapped_type corresponding to x in *this.
     //!
     //! Complexity: Logarithmic.
     mapped_type &operator[](const key_type& k);
  
     //! Effects: If there is no key equivalent to x in the flat_map, inserts
     //! value_type(move(x), T()) into the flat_map (the key is move-constructed)
     //!
     //! Returns: Allocator reference to the mapped_type corresponding to x in *this.
     //!
     //! Complexity: Logarithmic.
     mapped_type &operator[](key_type &&k) ;
  
     #else
     BOOST_MOVE_CONVERSION_AWARE_CATCH( operator[] , key_type, mapped_type&, this->priv_subscript)
     #endif
  
     //! Returns: Allocator reference to the element whose key is equivalent to x.
     //!
     //! Throws: An exception object of type out_of_range if no such element is present.
     //!
     //! Complexity: logarithmic.
     T& at(const key_type& k)
     {
        iterator i = this->find(k);
        if(i == this->end()){
           throw std::out_of_range("key not found");
        }
        return i->second;
     }
  
     //! Returns: Allocator reference to the element whose key is equivalent to x.
     //!
     //! Throws: An exception object of type out_of_range if no such element is present.
     //!
     //! Complexity: logarithmic.
     const T& at(const key_type& k) const
     {
        const_iterator i = this->find(k);
        if(i == this->end()){
           throw std::out_of_range("key not found");
        }
        return i->second;
     }
  
     //////////////////////////////////////////////
     //
     //                modifiers
     //
     //////////////////////////////////////////////
  
     #if defined(BOOST_CONTAINER_PERFECT_FORWARDING) || defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
  
     //! <b>Effects</b>: Inserts an object x of type T constructed with
     //!   std::forward<Args>(args)... if and only if there is no element in the container
     //!   with key equivalent to the key of x.
     //!
     //! <b>Returns</b>: The bool component of the returned pair is true if and only
     //!   if the insertion takes place, and the iterator component of the pair
     //!   points to the element with key equivalent to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     template <class... Args>
     std::pair<iterator,bool> emplace(Args&&... args)
     {  return container_detail::force_copy< std::pair<iterator, bool> >(m_flat_tree.emplace_unique(boost::forward<Args>(args)...)); }
  
     //! <b>Effects</b>: Inserts an object of type T constructed with
     //!   std::forward<Args>(args)... in the container if and only if there is
     //!   no element in the container with key equivalent to the key of x.
     //!   p is a hint pointing to where the insert should start to search.
     //!
     //! <b>Returns</b>: An iterator pointing to the element with key equivalent
     //!   to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
     //!   right before p) plus insertion linear to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     template <class... Args>
     iterator emplace_hint(const_iterator hint, Args&&... args)
     {
        return container_detail::force_copy<iterator>
           (m_flat_tree.emplace_hint_unique( container_detail::force_copy<impl_const_iterator>(hint)
                                           , boost::forward<Args>(args)...));
     }
  
     #else //#ifdef BOOST_CONTAINER_PERFECT_FORWARDING
  
     #define BOOST_PP_LOCAL_MACRO(n)                                                                 \
     BOOST_PP_EXPR_IF(n, template<) BOOST_PP_ENUM_PARAMS(n, class P) BOOST_PP_EXPR_IF(n, >)          \
     std::pair<iterator,bool> emplace(BOOST_PP_ENUM(n, BOOST_CONTAINER_PP_PARAM_LIST, _))            \
     {  return container_detail::force_copy< std::pair<iterator, bool> >                             \
           (m_flat_tree.emplace_unique(BOOST_PP_ENUM(n, BOOST_CONTAINER_PP_PARAM_FORWARD, _))); }    \
                                                                                                     \
     BOOST_PP_EXPR_IF(n, template<) BOOST_PP_ENUM_PARAMS(n, class P) BOOST_PP_EXPR_IF(n, >)          \
     iterator emplace_hint(const_iterator hint                                                       \
                           BOOST_PP_ENUM_TRAILING(n, BOOST_CONTAINER_PP_PARAM_LIST, _))              \
     {  return container_detail::force_copy<iterator>(m_flat_tree.emplace_hint_unique                \
              (container_detail::force_copy<impl_const_iterator>(hint)                               \
                 BOOST_PP_ENUM_TRAILING(n, BOOST_CONTAINER_PP_PARAM_FORWARD, _))); }                 \
     //!
     #define BOOST_PP_LOCAL_LIMITS (0, BOOST_CONTAINER_MAX_CONSTRUCTOR_PARAMETERS)
     #include BOOST_PP_LOCAL_ITERATE()
  
     #endif   //#ifdef BOOST_CONTAINER_PERFECT_FORWARDING
  
     //! <b>Effects</b>: Inserts x if and only if there is no element in the container
     //!   with key equivalent to the key of x.
     //!
     //! <b>Returns</b>: The bool component of the returned pair is true if and only
     //!   if the insertion takes place, and the iterator component of the pair
     //!   points to the element with key equivalent to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     std::pair<iterator,bool> insert(const value_type& x)
        { return container_detail::force_copy<std::pair<iterator,bool> >(
           m_flat_tree.insert_unique(container_detail::force<impl_value_type>(x))); }
  
     //! <b>Effects</b>: Inserts a new value_type move constructed from the pair if and
     //! only if there is no element in the container with key equivalent to the key of x.
     //!
     //! <b>Returns</b>: The bool component of the returned pair is true if and only
     //!   if the insertion takes place, and the iterator component of the pair
     //!   points to the element with key equivalent to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     std::pair<iterator,bool> insert(BOOST_RV_REF(value_type) x)
     {  return container_detail::force_copy<std::pair<iterator,bool> >(
        m_flat_tree.insert_unique(boost::move(container_detail::force<impl_value_type>(x)))); }
  
     //! <b>Effects</b>: Inserts a new value_type move constructed from the pair if and
     //! only if there is no element in the container with key equivalent to the key of x.
     //!
     //! <b>Returns</b>: The bool component of the returned pair is true if and only
     //!   if the insertion takes place, and the iterator component of the pair
     //!   points to the element with key equivalent to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     std::pair<iterator,bool> insert(BOOST_RV_REF(movable_value_type) x)
     {
        return container_detail::force_copy<std::pair<iterator,bool> >
        (m_flat_tree.insert_unique(boost::move(x)));
     }
  
     //! <b>Effects</b>: Inserts a copy of x in the container if and only if there is
     //!   no element in the container with key equivalent to the key of x.
     //!   p is a hint pointing to where the insert should start to search.
     //!
     //! <b>Returns</b>: An iterator pointing to the element with key equivalent
     //!   to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
     //!   right before p) plus insertion linear to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(const_iterator position, const value_type& x)
     {
        return container_detail::force_copy<iterator>(
           m_flat_tree.insert_unique( container_detail::force_copy<impl_const_iterator>(position)
                                    , container_detail::force<impl_value_type>(x)));
     }
  
     //! <b>Effects</b>: Inserts an element move constructed from x in the container.
     //!   p is a hint pointing to where the insert should start to search.
     //!
     //! <b>Returns</b>: An iterator pointing to the element with key equivalent to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
     //!   right before p) plus insertion linear to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(const_iterator position, BOOST_RV_REF(value_type) x)
     {
        return container_detail::force_copy<iterator>
           (m_flat_tree.insert_unique( container_detail::force_copy<impl_const_iterator>(position)
                                     , boost::move(container_detail::force<impl_value_type>(x))));
     }
  
     //! <b>Effects</b>: Inserts an element move constructed from x in the container.
     //!   p is a hint pointing to where the insert should start to search.
     //!
     //! <b>Returns</b>: An iterator pointing to the element with key equivalent to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
     //!   right before p) plus insertion linear to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(const_iterator position, BOOST_RV_REF(movable_value_type) x)
     {
        return container_detail::force_copy<iterator>(
           m_flat_tree.insert_unique(container_detail::force_copy<impl_const_iterator>(position), boost::move(x)));
     }
  
     //! <b>Requires</b>: first, last are not iterators into *this.
     //!
     //! <b>Effects</b>: inserts each element from the range [first,last) if and only
     //!   if there is no element with key equivalent to the key of that element.
     //!
     //! <b>Complexity</b>: At most N log(size()+N) (N is the distance from first to last)
     //!   search time plus N*size() insertion time.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     template <class InputIterator>
     void insert(InputIterator first, InputIterator last)
     {  m_flat_tree.insert_unique(first, last);  }
  
     //! <b>Requires</b>: first, last are not iterators into *this.
     //!
     //! <b>Requires</b>: [first ,last) must be ordered according to the predicate and must be
     //! unique values.
     //!
     //! <b>Effects</b>: inserts each element from the range [first,last) if and only
     //!   if there is no element with key equivalent to the key of that element. This
     //!   function is more efficient than the normal range creation for ordered ranges.
     //!
     //! <b>Complexity</b>: At most N log(size()+N) (N is the distance from first to last)
     //!   search time plus N*size() insertion time.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     template <class InputIterator>
     void insert(ordered_unique_range_t, InputIterator first, InputIterator last)
        {  m_flat_tree.insert_unique(ordered_unique_range, first, last); }
  
     //! <b>Effects</b>: Erases the element pointed to by position.
     //!
     //! <b>Returns</b>: Returns an iterator pointing to the element immediately
     //!   following q prior to the element being erased. If no such element exists,
     //!   returns end().
     //!
     //! <b>Complexity</b>: Linear to the elements with keys bigger than position
     //!
     //! <b>Note</b>: Invalidates elements with keys
     //!   not less than the erased element.
     iterator erase(const_iterator position)
     {
        return container_detail::force_copy<iterator>
           (m_flat_tree.erase(container_detail::force_copy<impl_const_iterator>(position)));
     }
  
     //! <b>Effects</b>: Erases all elements in the container with key equivalent to x.
     //!
     //! <b>Returns</b>: Returns the number of erased elements.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus erasure time
     //!   linear to the elements with bigger keys.
     size_type erase(const key_type& x)
        { return m_flat_tree.erase(x); }
  
     //! <b>Effects</b>: Erases all the elements in the range [first, last).
     //!
     //! <b>Returns</b>: Returns last.
     //!
     //! <b>Complexity</b>: size()*N where N is the distance from first to last.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus erasure time
     //!   linear to the elements with bigger keys.
     iterator erase(const_iterator first, const_iterator last)
     {
        return container_detail::force_copy<iterator>(
           m_flat_tree.erase( container_detail::force_copy<impl_const_iterator>(first)
                            , container_detail::force_copy<impl_const_iterator>(last)));
     }
  
     //! <b>Effects</b>: Swaps the contents of *this and x.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     void swap(flat_map& x)
     { m_flat_tree.swap(x.m_flat_tree); }
  
     //! <b>Effects</b>: erase(a.begin(),a.end()).
     //!
     //! <b>Postcondition</b>: size() == 0.
     //!
     //! <b>Complexity</b>: linear in size().
     void clear() BOOST_CONTAINER_NOEXCEPT
        { m_flat_tree.clear(); }
  
     //////////////////////////////////////////////
     //
     //                observers
     //
     //////////////////////////////////////////////
  
     //! <b>Effects</b>: Returns the comparison object out
     //!   of which a was constructed.
     //!
     //! <b>Complexity</b>: Constant.
     key_compare key_comp() const
        { return container_detail::force_copy<key_compare>(m_flat_tree.key_comp()); }
  
     //! <b>Effects</b>: Returns an object of value_compare constructed out
     //!   of the comparison object.
     //!
     //! <b>Complexity</b>: Constant.
     value_compare value_comp() const
        { return value_compare(container_detail::force_copy<key_compare>(m_flat_tree.key_comp())); }
  
     //////////////////////////////////////////////
     //
     //              map operations
     //
     //////////////////////////////////////////////
  
     //! <b>Returns</b>: An iterator pointing to an element with the key
     //!   equivalent to x, or end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic.
     iterator find(const key_type& x)
        { return container_detail::force_copy<iterator>(m_flat_tree.find(x)); }
  
     //! <b>Returns</b>: Allocator const_iterator pointing to an element with the key
     //!   equivalent to x, or end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic.s
     const_iterator find(const key_type& x) const
        { return container_detail::force_copy<const_iterator>(m_flat_tree.find(x)); }
  
     //! <b>Returns</b>: The number of elements with key equivalent to x.
     //!
     //! <b>Complexity</b>: log(size())+count(k)
     size_type count(const key_type& x) const
        {  return m_flat_tree.find(x) == m_flat_tree.end() ? 0 : 1;  }
  
     //! <b>Returns</b>: An iterator pointing to the first element with key not less
     //!   than k, or a.end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic
     iterator lower_bound(const key_type& x)
        {  return container_detail::force_copy<iterator>(m_flat_tree.lower_bound(x)); }
  
     //! <b>Returns</b>: Allocator const iterator pointing to the first element with key not
     //!   less than k, or a.end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic
     const_iterator lower_bound(const key_type& x) const
        {  return container_detail::force_copy<const_iterator>(m_flat_tree.lower_bound(x)); }
  
     //! <b>Returns</b>: An iterator pointing to the first element with key not less
     //!   than x, or end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic
     iterator upper_bound(const key_type& x)
        {  return container_detail::force_copy<iterator>(m_flat_tree.upper_bound(x)); }
  
     //! <b>Returns</b>: Allocator const iterator pointing to the first element with key not
     //!   less than x, or end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic
     const_iterator upper_bound(const key_type& x) const
        {  return container_detail::force_copy<const_iterator>(m_flat_tree.upper_bound(x)); }
  
     //! <b>Effects</b>: Equivalent to std::make_pair(this->lower_bound(k), this->upper_bound(k)).
     //!
     //! <b>Complexity</b>: Logarithmic
     std::pair<iterator,iterator> equal_range(const key_type& x)
        {  return container_detail::force_copy<std::pair<iterator,iterator> >(m_flat_tree.equal_range(x)); }
  
     //! <b>Effects</b>: Equivalent to std::make_pair(this->lower_bound(k), this->upper_bound(k)).
     //!
     //! <b>Complexity</b>: Logarithmic
     std::pair<const_iterator,const_iterator> equal_range(const key_type& x) const
        {  return container_detail::force_copy<std::pair<const_iterator,const_iterator> >(m_flat_tree.equal_range(x)); }
  
     /// @cond
     template <class K1, class T1, class C1, class A1>
     friend bool operator== (const flat_map<K1, T1, C1, A1>&,
                             const flat_map<K1, T1, C1, A1>&);
     template <class K1, class T1, class C1, class A1>
     friend bool operator< (const flat_map<K1, T1, C1, A1>&,
                             const flat_map<K1, T1, C1, A1>&);
  
     private:
     mapped_type &priv_subscript(const key_type& k)
     {
        iterator i = lower_bound(k);
        // i->first is greater than or equivalent to k.
        if (i == end() || key_comp()(k, (*i).first)){
           container_detail::value_init<mapped_type> m;
           i = insert(i, impl_value_type(k, ::boost::move(m.m_t)));
        }
        return (*i).second;
     }
     mapped_type &priv_subscript(BOOST_RV_REF(key_type) mk)
     {
        key_type &k = mk;
        iterator i = lower_bound(k);
        // i->first is greater than or equivalent to k.
        if (i == end() || key_comp()(k, (*i).first)){
           container_detail::value_init<mapped_type> m;
           i = insert(i, impl_value_type(boost::move(k), ::boost::move(m.m_t)));
        }
        return (*i).second;
     }
     /// @endcond
  };
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator==(const flat_map<Key,T,Compare,Allocator>& x,
                         const flat_map<Key,T,Compare,Allocator>& y)
     {  return x.m_flat_tree == y.m_flat_tree;  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator<(const flat_map<Key,T,Compare,Allocator>& x,
                        const flat_map<Key,T,Compare,Allocator>& y)
     {  return x.m_flat_tree < y.m_flat_tree;   }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator!=(const flat_map<Key,T,Compare,Allocator>& x,
                         const flat_map<Key,T,Compare,Allocator>& y)
     {  return !(x == y); }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator>(const flat_map<Key,T,Compare,Allocator>& x,
                        const flat_map<Key,T,Compare,Allocator>& y)
     {  return y < x;  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator<=(const flat_map<Key,T,Compare,Allocator>& x,
                         const flat_map<Key,T,Compare,Allocator>& y)
     {  return !(y < x);  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator>=(const flat_map<Key,T,Compare,Allocator>& x,
                         const flat_map<Key,T,Compare,Allocator>& y)
     {  return !(x < y);  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline void swap(flat_map<Key,T,Compare,Allocator>& x,
                   flat_map<Key,T,Compare,Allocator>& y)
     {  x.swap(y);  }
  
  /// @cond
  
  }  //namespace container {
  
  //!has_trivial_destructor_after_move<> == true_type
  //!specialization for optimizations
  template <class K, class T, class C, class Allocator>
  struct has_trivial_destructor_after_move<boost::container::flat_map<K, T, C, Allocator> >
  {
     static const bool value = has_trivial_destructor_after_move<Allocator>::value && has_trivial_destructor_after_move<C>::value;
  };
  
  namespace container {
  
  // Forward declaration of operators < and ==, needed for friend declaration.
  template <class Key, class T, class Compare, class Allocator>
  class flat_multimap;
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator==(const flat_multimap<Key,T,Compare,Allocator>& x,
                         const flat_multimap<Key,T,Compare,Allocator>& y);
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator<(const flat_multimap<Key,T,Compare,Allocator>& x,
                        const flat_multimap<Key,T,Compare,Allocator>& y);
  /// @endcond
  
  //! A flat_multimap is a kind of associative container that supports equivalent keys
  //! (possibly containing multiple copies of the same key value) and provides for
  //! fast retrieval of values of another type T based on the keys. The flat_multimap
  //! class supports random-access iterators.
  //!
  //! A flat_multimap satisfies all of the requirements of a container and of a reversible
  //! container and of an associative container. For a
  //! flat_multimap<Key,T> the key_type is Key and the value_type is std::pair<Key,T>
  //! (unlike std::multimap<Key, T> which value_type is std::pair<<b>const</b> Key, T>).
  //!
  //! Compare is the ordering function for Keys (e.g. <i>std::less<Key></i>).
  //!
  //! Allocator is the allocator to allocate the value_types
  //! (e.g. <i>allocator< std::pair<Key, T> ></i>).
  #ifdef BOOST_CONTAINER_DOXYGEN_INVOKED
  template <class Key, class T, class Compare = std::less<Key>, class Allocator = std::allocator< std::pair< Key, T> > >
  #else
  template <class Key, class T, class Compare, class Allocator>
  #endif
  class flat_multimap
  {
     /// @cond
     private:
     BOOST_COPYABLE_AND_MOVABLE(flat_multimap)
     typedef container_detail::flat_tree<Key,
                             std::pair<Key, T>,
                             container_detail::select1st< std::pair<Key, T> >,
                             Compare,
                             Allocator> tree_t;
     //This is the real tree stored here. It's based on a movable pair
     typedef container_detail::flat_tree<Key,
                             container_detail::pair<Key, T>,
                             container_detail::select1st<container_detail::pair<Key, T> >,
                             Compare,
                             typename allocator_traits<Allocator>::template portable_rebind_alloc
                                <container_detail::pair<Key, T> >::type> impl_tree_t;
     impl_tree_t m_flat_tree;  // flat tree representing flat_map
  
     typedef typename impl_tree_t::value_type              impl_value_type;
     typedef typename impl_tree_t::const_iterator          impl_const_iterator;
     typedef typename impl_tree_t::allocator_type          impl_allocator_type;
     typedef container_detail::flat_tree_value_compare
        < Compare
        , container_detail::select1st< std::pair<Key, T> >
        , std::pair<Key, T> >                                                         value_compare_impl;
     typedef typename container_detail::get_flat_tree_iterators
           <typename allocator_traits<Allocator>::pointer>::iterator                  iterator_impl;
     typedef typename container_detail::get_flat_tree_iterators
        <typename allocator_traits<Allocator>::pointer>::const_iterator               const_iterator_impl;
     typedef typename container_detail::get_flat_tree_iterators
           <typename allocator_traits<Allocator>::pointer>::reverse_iterator          reverse_iterator_impl;
     typedef typename container_detail::get_flat_tree_iterators
           <typename allocator_traits<Allocator>::pointer>::const_reverse_iterator    const_reverse_iterator_impl;
     /// @endcond
  
     public:
  
     //////////////////////////////////////////////
     //
     //                    types
     //
     //////////////////////////////////////////////
     typedef Key                                                                      key_type;
     typedef T                                                                        mapped_type;
     typedef std::pair<Key, T>                                                        value_type;
     typedef typename boost::container::allocator_traits<Allocator>::pointer          pointer;
     typedef typename boost::container::allocator_traits<Allocator>::const_pointer    const_pointer;
     typedef typename boost::container::allocator_traits<Allocator>::reference        reference;
     typedef typename boost::container::allocator_traits<Allocator>::const_reference  const_reference;
     typedef typename boost::container::allocator_traits<Allocator>::size_type        size_type;
     typedef typename boost::container::allocator_traits<Allocator>::difference_type  difference_type;
     typedef Allocator                                                                allocator_type;
     typedef BOOST_CONTAINER_IMPDEF(Allocator)                                        stored_allocator_type;
     typedef BOOST_CONTAINER_IMPDEF(value_compare_impl)                               value_compare;
     typedef Compare                                                                  key_compare;
     typedef BOOST_CONTAINER_IMPDEF(iterator_impl)                                    iterator;
     typedef BOOST_CONTAINER_IMPDEF(const_iterator_impl)                              const_iterator;
     typedef BOOST_CONTAINER_IMPDEF(reverse_iterator_impl)                            reverse_iterator;
     typedef BOOST_CONTAINER_IMPDEF(const_reverse_iterator_impl)                      const_reverse_iterator;
     typedef BOOST_CONTAINER_IMPDEF(impl_value_type)                                  movable_value_type;
  
     //////////////////////////////////////////////
     //
     //          construct/copy/destroy
     //
     //////////////////////////////////////////////
  
     //! <b>Effects</b>: Default constructs an empty flat_map.
     //!
     //! <b>Complexity</b>: Constant.
     flat_multimap()
        : m_flat_tree() {}
  
     //! <b>Effects</b>: Constructs an empty flat_multimap using the specified comparison
     //!   object and allocator.
     //!
     //! <b>Complexity</b>: Constant.
     explicit flat_multimap(const Compare& comp,
                            const allocator_type& a = allocator_type())
        : m_flat_tree(comp, container_detail::force<impl_allocator_type>(a)) { }
  
     //! <b>Effects</b>: Constructs an empty flat_multimap using the specified comparison object
     //!   and allocator, and inserts elements from the range [first ,last ).
     //!
     //! <b>Complexity</b>: Linear in N if the range [first ,last ) is already sorted using
     //! comp and otherwise N logN, where N is last - first.
     template <class InputIterator>
     flat_multimap(InputIterator first, InputIterator last,
              const Compare& comp        = Compare(),
              const allocator_type& a = allocator_type())
        : m_flat_tree(false, first, last, comp, container_detail::force<impl_allocator_type>(a))
     {}
  
     //! <b>Effects</b>: Constructs an empty flat_multimap using the specified comparison object and
     //! allocator, and inserts elements from the ordered range [first ,last). This function
     //! is more efficient than the normal range creation for ordered ranges.
     //!
     //! <b>Requires</b>: [first ,last) must be ordered according to the predicate.
     //!
     //! <b>Complexity</b>: Linear in N.
     //!
     //! <b>Note</b>: Non-standard extension.
     template <class InputIterator>
     flat_multimap(ordered_range_t, InputIterator first, InputIterator last,
              const Compare& comp        = Compare(),
              const allocator_type& a = allocator_type())
        : m_flat_tree(ordered_range, first, last, comp, a)
     {}
  
     //! <b>Effects</b>: Copy constructs a flat_multimap.
     //!
     //! <b>Complexity</b>: Linear in x.size().
     flat_multimap(const flat_multimap& x)
        : m_flat_tree(x.m_flat_tree) { }
  
     //! <b>Effects</b>: Move constructs a flat_multimap. Constructs *this using x's resources.
     //!
     //! <b>Complexity</b>: Constant.
     //!
     //! <b>Postcondition</b>: x is emptied.
     flat_multimap(BOOST_RV_REF(flat_multimap) x)
        : m_flat_tree(boost::move(x.m_flat_tree))
     {}
  
     //! <b>Effects</b>: Copy constructs a flat_multimap using the specified allocator.
     //!
     //! <b>Complexity</b>: Linear in x.size().
     flat_multimap(const flat_multimap& x, const allocator_type &a)
        : m_flat_tree(x.m_flat_tree, a)
     {}
  
     //! <b>Effects</b>: Move constructs a flat_multimap using the specified allocator.
     //!                 Constructs *this using x's resources.
     //!
     //! <b>Complexity</b>: Constant if a == x.get_allocator(), linear otherwise.
     flat_multimap(BOOST_RV_REF(flat_multimap) x, const allocator_type &a)
        : m_flat_tree(boost::move(x.m_flat_tree), a)
     { }
  
     //! <b>Effects</b>: Makes *this a copy of x.
     //!
     //! <b>Complexity</b>: Linear in x.size().
     flat_multimap& operator=(BOOST_COPY_ASSIGN_REF(flat_multimap) x)
        {  m_flat_tree = x.m_flat_tree;   return *this;  }
  
     //! <b>Effects</b>: this->swap(x.get()).
     //!
     //! <b>Complexity</b>: Constant.
     flat_multimap& operator=(BOOST_RV_REF(flat_multimap) mx)
        {  m_flat_tree = boost::move(mx.m_flat_tree);   return *this;  }
  
     //! <b>Effects</b>: Returns a copy of the Allocator that
     //!   was passed to the object's constructor.
     //!
     //! <b>Complexity</b>: Constant.
     allocator_type get_allocator() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<allocator_type>(m_flat_tree.get_allocator()); }
  
     //! <b>Effects</b>: Returns a reference to the internal allocator.
     //!
     //! <b>Throws</b>: Nothing
     //!
     //! <b>Complexity</b>: Constant.
     //!
     //! <b>Note</b>: Non-standard extension.
     stored_allocator_type &get_stored_allocator() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force<stored_allocator_type>(m_flat_tree.get_stored_allocator()); }
  
     //! <b>Effects</b>: Returns a reference to the internal allocator.
     //!
     //! <b>Throws</b>: Nothing
     //!
     //! <b>Complexity</b>: Constant.
     //!
     //! <b>Note</b>: Non-standard extension.
     const stored_allocator_type &get_stored_allocator() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force<stored_allocator_type>(m_flat_tree.get_stored_allocator()); }
  
     //////////////////////////////////////////////
     //
     //                iterators
     //
     //////////////////////////////////////////////
  
     //! <b>Effects</b>: Returns an iterator to the first element contained in the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     iterator begin() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<iterator>(m_flat_tree.begin()); }
  
     //! <b>Effects</b>: Returns a const_iterator to the first element contained in the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_iterator begin() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_iterator>(m_flat_tree.begin()); }
  
     //! <b>Effects</b>: Returns an iterator to the end of the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     iterator end() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<iterator>(m_flat_tree.end()); }
  
     //! <b>Effects</b>: Returns a const_iterator to the end of the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_iterator end() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_iterator>(m_flat_tree.end()); }
  
     //! <b>Effects</b>: Returns a reverse_iterator pointing to the beginning
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     reverse_iterator rbegin() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<reverse_iterator>(m_flat_tree.rbegin()); }
  
     //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the beginning
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_reverse_iterator rbegin() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_reverse_iterator>(m_flat_tree.rbegin()); }
  
     //! <b>Effects</b>: Returns a reverse_iterator pointing to the end
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     reverse_iterator rend() BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<reverse_iterator>(m_flat_tree.rend()); }
  
     //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the end
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_reverse_iterator rend() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_reverse_iterator>(m_flat_tree.rend()); }
  
     //! <b>Effects</b>: Returns a const_iterator to the first element contained in the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_iterator cbegin() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_iterator>(m_flat_tree.cbegin()); }
  
     //! <b>Effects</b>: Returns a const_iterator to the end of the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_iterator cend() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_iterator>(m_flat_tree.cend()); }
  
     //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the beginning
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_reverse_iterator crbegin() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_reverse_iterator>(m_flat_tree.crbegin()); }
  
     //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the end
     //! of the reversed container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     const_reverse_iterator crend() const BOOST_CONTAINER_NOEXCEPT
        { return container_detail::force_copy<const_reverse_iterator>(m_flat_tree.crend()); }
  
     //////////////////////////////////////////////
     //
     //                capacity
     //
     //////////////////////////////////////////////
  
     //! <b>Effects</b>: Returns true if the container contains no elements.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     bool empty() const BOOST_CONTAINER_NOEXCEPT
        { return m_flat_tree.empty(); }
  
     //! <b>Effects</b>: Returns the number of the elements contained in the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     size_type size() const BOOST_CONTAINER_NOEXCEPT
        { return m_flat_tree.size(); }
  
     //! <b>Effects</b>: Returns the largest possible size of the container.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     size_type max_size() const BOOST_CONTAINER_NOEXCEPT
        { return m_flat_tree.max_size(); }
  
     //! <b>Effects</b>: Number of elements for which memory has been allocated.
     //!   capacity() is always greater than or equal to size().
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     size_type capacity() const BOOST_CONTAINER_NOEXCEPT
        { return m_flat_tree.capacity(); }
  
     //! <b>Effects</b>: If n is less than or equal to capacity(), this call has no
     //!   effect. Otherwise, it is a request for allocation of additional memory.
     //!   If the request is successful, then capacity() is greater than or equal to
     //!   n; otherwise, capacity() is unchanged. In either case, size() is unchanged.
     //!
     //! <b>Throws</b>: If memory allocation allocation throws or T's copy constructor throws.
     //!
     //! <b>Note</b>: If capacity() is less than "cnt", iterators and references to
     //!   to values might be invalidated.
     void reserve(size_type cnt)      
        { m_flat_tree.reserve(cnt);   }
  
     //! <b>Effects</b>: Tries to deallocate the excess of memory created
     //    with previous allocations. The size of the vector is unchanged
     //!
     //! <b>Throws</b>: If memory allocation throws, or T's copy constructor throws.
     //!
     //! <b>Complexity</b>: Linear to size().
     void shrink_to_fit()
        { m_flat_tree.shrink_to_fit(); }
  
     //////////////////////////////////////////////
     //
     //                modifiers
     //
     //////////////////////////////////////////////
  
     #if defined(BOOST_CONTAINER_PERFECT_FORWARDING) || defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
  
     //! <b>Effects</b>: Inserts an object of type T constructed with
     //!   std::forward<Args>(args)... and returns the iterator pointing to the
     //!   newly inserted element.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     template <class... Args>
     iterator emplace(Args&&... args)
     {  return container_detail::force_copy<iterator>(m_flat_tree.emplace_equal(boost::forward<Args>(args)...)); }
  
     //! <b>Effects</b>: Inserts an object of type T constructed with
     //!   std::forward<Args>(args)... in the container.
     //!   p is a hint pointing to where the insert should start to search.
     //!
     //! <b>Returns</b>: An iterator pointing to the element with key equivalent
     //!   to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time (constant time if the value
     //!   is to be inserted before p) plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     template <class... Args>
     iterator emplace_hint(const_iterator hint, Args&&... args)
     {
        return container_detail::force_copy<iterator>(m_flat_tree.emplace_hint_equal
           (container_detail::force_copy<impl_const_iterator>(hint), boost::forward<Args>(args)...));
     }
  
     #else //#ifdef BOOST_CONTAINER_PERFECT_FORWARDING
  
     #define BOOST_PP_LOCAL_MACRO(n)                                                                 \
     BOOST_PP_EXPR_IF(n, template<) BOOST_PP_ENUM_PARAMS(n, class P) BOOST_PP_EXPR_IF(n, >)          \
     iterator emplace(BOOST_PP_ENUM(n, BOOST_CONTAINER_PP_PARAM_LIST, _))                            \
     {  return container_detail::force_copy<iterator>(m_flat_tree.emplace_equal                      \
                 (BOOST_PP_ENUM(n, BOOST_CONTAINER_PP_PARAM_FORWARD, _))); }                         \
                                                                                                     \
     BOOST_PP_EXPR_IF(n, template<) BOOST_PP_ENUM_PARAMS(n, class P) BOOST_PP_EXPR_IF(n, >)          \
     iterator emplace_hint(const_iterator hint                                                       \
                           BOOST_PP_ENUM_TRAILING(n, BOOST_CONTAINER_PP_PARAM_LIST, _))              \
     {  return container_detail::force_copy<iterator>(m_flat_tree.emplace_hint_equal                 \
              (container_detail::force_copy<impl_const_iterator>(hint)                               \
                 BOOST_PP_ENUM_TRAILING(n, BOOST_CONTAINER_PP_PARAM_FORWARD, _))); }                 \
     //!
     #define BOOST_PP_LOCAL_LIMITS (0, BOOST_CONTAINER_MAX_CONSTRUCTOR_PARAMETERS)
     #include BOOST_PP_LOCAL_ITERATE()
  
     #endif   //#ifdef BOOST_CONTAINER_PERFECT_FORWARDING
  
     //! <b>Effects</b>: Inserts x and returns the iterator pointing to the
     //!   newly inserted element.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(const value_type& x)
     {
        return container_detail::force_copy<iterator>(
           m_flat_tree.insert_equal(container_detail::force<impl_value_type>(x)));
     }
  
     //! <b>Effects</b>: Inserts a new value move-constructed from x and returns
     //!   the iterator pointing to the newly inserted element.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(BOOST_RV_REF(value_type) x)
     { return container_detail::force_copy<iterator>(m_flat_tree.insert_equal(boost::move(x))); }
  
     //! <b>Effects</b>: Inserts a new value move-constructed from x and returns
     //!   the iterator pointing to the newly inserted element.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(BOOST_RV_REF(impl_value_type) x)
        { return container_detail::force_copy<iterator>(m_flat_tree.insert_equal(boost::move(x))); }
  
     //! <b>Effects</b>: Inserts a copy of x in the container.
     //!   p is a hint pointing to where the insert should start to search.
     //!
     //! <b>Returns</b>: An iterator pointing to the element with key equivalent
     //!   to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time (constant time if the value
     //!   is to be inserted before p) plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(const_iterator position, const value_type& x)
     {
        return container_detail::force_copy<iterator>
           (m_flat_tree.insert_equal( container_detail::force_copy<impl_const_iterator>(position)
                                    , container_detail::force<impl_value_type>(x)));
     }
  
     //! <b>Effects</b>: Inserts a value move constructed from x in the container.
     //!   p is a hint pointing to where the insert should start to search.
     //!
     //! <b>Returns</b>: An iterator pointing to the element with key equivalent
     //!   to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time (constant time if the value
     //!   is to be inserted before p) plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(const_iterator position, BOOST_RV_REF(value_type) x)
     {
        return container_detail::force_copy<iterator>
           (m_flat_tree.insert_equal(container_detail::force_copy<impl_const_iterator>(position)
                                    , boost::move(x)));
     }
  
     //! <b>Effects</b>: Inserts a value move constructed from x in the container.
     //!   p is a hint pointing to where the insert should start to search.
     //!
     //! <b>Returns</b>: An iterator pointing to the element with key equivalent
     //!   to the key of x.
     //!
     //! <b>Complexity</b>: Logarithmic search time (constant time if the value
     //!   is to be inserted before p) plus linear insertion
     //!   to the elements with bigger keys than x.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     iterator insert(const_iterator position, BOOST_RV_REF(impl_value_type) x)
     {
        return container_detail::force_copy<iterator>(
           m_flat_tree.insert_equal(container_detail::force_copy<impl_const_iterator>(position), boost::move(x)));
     }
  
     //! <b>Requires</b>: first, last are not iterators into *this.
     //!
     //! <b>Effects</b>: inserts each element from the range [first,last) .
     //!
     //! <b>Complexity</b>: At most N log(size()+N) (N is the distance from first to last)
     //!   search time plus N*size() insertion time.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     template <class InputIterator>
     void insert(InputIterator first, InputIterator last)
        {  m_flat_tree.insert_equal(first, last); }
  
     //! <b>Requires</b>: first, last are not iterators into *this.
     //!
     //! <b>Requires</b>: [first ,last) must be ordered according to the predicate.
     //!
     //! <b>Effects</b>: inserts each element from the range [first,last) if and only
     //!   if there is no element with key equivalent to the key of that element. This
     //!   function is more efficient than the normal range creation for ordered ranges.
     //!
     //! <b>Complexity</b>: At most N log(size()+N) (N is the distance from first to last)
     //!   search time plus N*size() insertion time.
     //!
     //! <b>Note</b>: If an element is inserted it might invalidate elements.
     template <class InputIterator>
     void insert(ordered_range_t, InputIterator first, InputIterator last)
        {  m_flat_tree.insert_equal(ordered_range, first, last); }
  
     //! <b>Effects</b>: Erases the element pointed to by position.
     //!
     //! <b>Returns</b>: Returns an iterator pointing to the element immediately
     //!   following q prior to the element being erased. If no such element exists,
     //!   returns end().
     //!
     //! <b>Complexity</b>: Linear to the elements with keys bigger than position
     //!
     //! <b>Note</b>: Invalidates elements with keys
     //!   not less than the erased element.
     iterator erase(const_iterator position)
     {
        return container_detail::force_copy<iterator>(
           m_flat_tree.erase(container_detail::force_copy<impl_const_iterator>(position)));
     }
  
     //! <b>Effects</b>: Erases all elements in the container with key equivalent to x.
     //!
     //! <b>Returns</b>: Returns the number of erased elements.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus erasure time
     //!   linear to the elements with bigger keys.
     size_type erase(const key_type& x)
        { return m_flat_tree.erase(x); }
  
     //! <b>Effects</b>: Erases all the elements in the range [first, last).
     //!
     //! <b>Returns</b>: Returns last.
     //!
     //! <b>Complexity</b>: size()*N where N is the distance from first to last.
     //!
     //! <b>Complexity</b>: Logarithmic search time plus erasure time
     //!   linear to the elements with bigger keys.
     iterator erase(const_iterator first, const_iterator last)
     {
        return container_detail::force_copy<iterator>
           (m_flat_tree.erase( container_detail::force_copy<impl_const_iterator>(first)
                             , container_detail::force_copy<impl_const_iterator>(last)));
     }
  
     //! <b>Effects</b>: Swaps the contents of *this and x.
     //!
     //! <b>Throws</b>: Nothing.
     //!
     //! <b>Complexity</b>: Constant.
     void swap(flat_multimap& x)
     { m_flat_tree.swap(x.m_flat_tree); }
  
     //! <b>Effects</b>: erase(a.begin(),a.end()).
     //!
     //! <b>Postcondition</b>: size() == 0.
     //!
     //! <b>Complexity</b>: linear in size().
     void clear() BOOST_CONTAINER_NOEXCEPT
        { m_flat_tree.clear(); }
  
     //////////////////////////////////////////////
     //
     //                observers
     //
     //////////////////////////////////////////////
  
     //! <b>Effects</b>: Returns the comparison object out
     //!   of which a was constructed.
     //!
     //! <b>Complexity</b>: Constant.
     key_compare key_comp() const
        { return container_detail::force_copy<key_compare>(m_flat_tree.key_comp()); }
  
     //! <b>Effects</b>: Returns an object of value_compare constructed out
     //!   of the comparison object.
     //!
     //! <b>Complexity</b>: Constant.
     value_compare value_comp() const
        { return value_compare(container_detail::force_copy<key_compare>(m_flat_tree.key_comp())); }
  
     //////////////////////////////////////////////
     //
     //              map operations
     //
     //////////////////////////////////////////////
  
     //! <b>Returns</b>: An iterator pointing to an element with the key
     //!   equivalent to x, or end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic.
     iterator find(const key_type& x)
        { return container_detail::force_copy<iterator>(m_flat_tree.find(x)); }
  
     //! <b>Returns</b>: An const_iterator pointing to an element with the key
     //!   equivalent to x, or end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic.
     const_iterator find(const key_type& x) const
        { return container_detail::force_copy<const_iterator>(m_flat_tree.find(x)); }
  
     //! <b>Returns</b>: The number of elements with key equivalent to x.
     //!
     //! <b>Complexity</b>: log(size())+count(k)
     size_type count(const key_type& x) const
        { return m_flat_tree.count(x); }
  
     //! <b>Returns</b>: An iterator pointing to the first element with key not less
     //!   than k, or a.end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic
     iterator lower_bound(const key_type& x)
        {  return container_detail::force_copy<iterator>(m_flat_tree.lower_bound(x)); }
  
     //! <b>Returns</b>: Allocator const iterator pointing to the first element with key
     //!   not less than k, or a.end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic
     const_iterator lower_bound(const key_type& x) const
        {  return container_detail::force_copy<const_iterator>(m_flat_tree.lower_bound(x));  }
  
     //! <b>Returns</b>: An iterator pointing to the first element with key not less
     //!   than x, or end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic
     iterator upper_bound(const key_type& x)
        {return container_detail::force_copy<iterator>(m_flat_tree.upper_bound(x)); }
  
     //! <b>Returns</b>: Allocator const iterator pointing to the first element with key
     //!   not less than x, or end() if such an element is not found.
     //!
     //! <b>Complexity</b>: Logarithmic
     const_iterator upper_bound(const key_type& x) const
        {  return container_detail::force_copy<const_iterator>(m_flat_tree.upper_bound(x)); }
  
     //! <b>Effects</b>: Equivalent to std::make_pair(this->lower_bound(k), this->upper_bound(k)).
     //!
     //! <b>Complexity</b>: Logarithmic
     std::pair<iterator,iterator> equal_range(const key_type& x)
        {  return container_detail::force_copy<std::pair<iterator,iterator> >(m_flat_tree.equal_range(x));   }
  
     //! <b>Effects</b>: Equivalent to std::make_pair(this->lower_bound(k), this->upper_bound(k)).
     //!
     //! <b>Complexity</b>: Logarithmic
     std::pair<const_iterator,const_iterator> equal_range(const key_type& x) const
        {  return container_detail::force_copy<std::pair<const_iterator,const_iterator> >(m_flat_tree.equal_range(x));   }
  
     /// @cond
     template <class K1, class T1, class C1, class A1>
     friend bool operator== (const flat_multimap<K1, T1, C1, A1>& x,
                             const flat_multimap<K1, T1, C1, A1>& y);
  
     template <class K1, class T1, class C1, class A1>
     friend bool operator< (const flat_multimap<K1, T1, C1, A1>& x,
                            const flat_multimap<K1, T1, C1, A1>& y);
     /// @endcond
  };
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator==(const flat_multimap<Key,T,Compare,Allocator>& x,
                         const flat_multimap<Key,T,Compare,Allocator>& y)
     {  return x.m_flat_tree == y.m_flat_tree;  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator<(const flat_multimap<Key,T,Compare,Allocator>& x,
                        const flat_multimap<Key,T,Compare,Allocator>& y)
     {  return x.m_flat_tree < y.m_flat_tree;   }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator!=(const flat_multimap<Key,T,Compare,Allocator>& x,
                         const flat_multimap<Key,T,Compare,Allocator>& y)
     {  return !(x == y);  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator>(const flat_multimap<Key,T,Compare,Allocator>& x,
                        const flat_multimap<Key,T,Compare,Allocator>& y)
     {  return y < x;  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator<=(const flat_multimap<Key,T,Compare,Allocator>& x,
                         const flat_multimap<Key,T,Compare,Allocator>& y)
     {  return !(y < x);  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline bool operator>=(const flat_multimap<Key,T,Compare,Allocator>& x,
                         const flat_multimap<Key,T,Compare,Allocator>& y)
     {  return !(x < y);  }
  
  template <class Key, class T, class Compare, class Allocator>
  inline void swap(flat_multimap<Key,T,Compare,Allocator>& x, flat_multimap<Key,T,Compare,Allocator>& y)
     {  x.swap(y);  }
  
  }}
  
  /// @cond
  
  namespace boost {
  
  //!has_trivial_destructor_after_move<> == true_type
  //!specialization for optimizations
  template <class K, class T, class C, class Allocator>
  struct has_trivial_destructor_after_move< boost::container::flat_multimap<K, T, C, Allocator> >
  {
     static const bool value = has_trivial_destructor_after_move<Allocator>::value && has_trivial_destructor_after_move<C>::value;
  };
  
  }  //namespace boost {
  
  /// @endcond
  
  #include <boost/container/detail/config_end.hpp>
  
  #endif /* BOOST_CONTAINER_FLAT_MAP_HPP */
  