concurrent_unordered_map.h

/***
* ==++==
*
* Copyright (c) Microsoft Corporation.  All rights reserved.
*
* ==--==
* =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
*
* concurrent_unordered_map.h
*
* =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
****/
#pragma once

#include <utility>
#include "internal_concurrent_hash.h"

#define _PPL_CONTAINER

#if !(defined (_M_X64) || defined (_M_IX86) || defined (_M_ARM) || defined (_M_ARM64))
    #error ERROR: Concurrency Runtime is supported only on X64, X86, ARM, and ARM64 architectures.
#endif  /* !(defined (_M_X64) || defined (_M_IX86) || defined (_M_ARM) || defined (_M_ARM64)) */

#if defined (_M_CEE)
    #error ERROR: Concurrency Runtime is not supported when compiling /clr.
#endif  /* defined (_M_CEE) */

#pragma pack(push,_CRT_PACKING)
#pragma warning(push)
#pragma warning(disable: 4100) // Unreferenced formal parameter - needed for document generation

namespace Concurrency
{
namespace details
{
// Template class for hash map traits
template<typename _Key_type, typename _Element_type, typename _Key_comparator, typename _Allocator_type, bool _Allow_multimapping>
class _Concurrent_unordered_map_traits : public ::std::_Container_base
{
public:
    typedef ::std::pair<const _Key_type, _Element_type> value_type;
    typedef _Key_type key_type;
    typedef _Key_comparator _Key_compare;

    typedef typename ::std::allocator_traits<_Allocator_type>::template rebind_alloc<value_type> allocator_type;

    enum
    {
        _M_allow_multimapping = _Allow_multimapping
    };

    _Concurrent_unordered_map_traits() : _M_comparator()
    {
    }

    _Concurrent_unordered_map_traits(const _Key_compare& _Traits) : _M_comparator(_Traits)
    {
    }

    class _Value_compare
    {
        friend class _Concurrent_unordered_map_traits<_Key_type, _Element_type, _Key_comparator, _Allocator_type, _Allow_multimapping>;

    public:
        typedef value_type first_argument_type;
        typedef value_type second_argument_type;
        typedef bool result_type;

        bool operator()(const value_type& _Left, const value_type& _Right) const
        {
            return (_M_comparator(_Left.first, _Right.first));
        }

        _Value_compare(const _Key_compare& _Traits) : _M_comparator(_Traits)
        {
        }

    protected:
        _Key_compare _M_comparator;    // the comparator predicate for keys
    };

    template<class _Type1, class _Type2>
    static const _Type1& _Key_function(const ::std::pair<_Type1, _Type2>& _Value)
    {
        return (_Value.first);
    }
    _Key_compare _M_comparator; // the comparator predicate for keys
};
} // namespace details;

/// <summary>
///     The <c>concurrent_unordered_map</c> class is a concurrency-safe container that controls a varying-length sequence of
///     elements of type <c>std::pair&lt;const _Key_type, _Element_type&gt;</c>. The sequence is represented in a way that enables concurrency-safe
///     append, element access, iterator access, and iterator traversal operations.
/// </summary>
/// <typeparam name="_Key_type">
///     The key type.
/// </typeparam>
/// <typeparam name="_Element_type">
///     The mapped type.
/// </typeparam>
/// <typeparam name="_Hasher">
///     The hash function object type. This argument is optional and the default value is
///     <c>std::hash&lt;</c><typeparamref name="_Key_type"/><c>&gt;</c>.
/// </typeparam>
/// <typeparam name="_Key_equality">
///     The equality comparison function object type. This argument is optional and the default value is
///     <c>std::equal_to&lt;</c><typeparamref name="_Key_type"/><c>&gt;</c>.
/// </typeparam>
/// <typeparam name="_Allocator_type">
///     The type that represents the stored allocator object that encapsulates details about the allocation and
///     deallocation of memory for the concurrent unordered map. This argument is optional and the default value is
///     <c>std::allocator&lt;std::pair&lt;</c><typeparamref name="_Key_type"/>, <typeparamref name="_Element_type"/><c>&gt;&gt;</c>.
/// </typeparam>
/// <remarks>
///     For detailed information on the <c>concurrent_unordered_map</c> class, see <see cref="Parallel Containers and Objects"/>.
/// </remarks>
/// <seealso cref="Parallel Containers and Objects"/>
/**/
template <typename _Key_type, typename _Element_type, typename _Hasher = ::std::hash<_Key_type>, typename _Key_equality = ::std::equal_to<_Key_type>, typename _Allocator_type = ::std::allocator<::std::pair<const _Key_type, _Element_type>>>
class concurrent_unordered_map : public details::_Concurrent_hash< details::_Concurrent_unordered_map_traits<_Key_type, _Element_type, details::_Hash_compare<_Key_type, _Hasher, _Key_equality>, _Allocator_type, false>>
{
public:
    // Base type definitions
    typedef concurrent_unordered_map<_Key_type, _Element_type, _Hasher, _Key_equality, _Allocator_type> _Mytype;
    typedef details::_Hash_compare<_Key_type, _Hasher, _Key_equality> _Key_compare;
    typedef details::_Concurrent_hash< details::_Concurrent_unordered_map_traits<_Key_type, _Element_type, _Key_compare, _Allocator_type, false>> _Mybase;

    /// <summary>
    ///     The type of an ordering key.
    /// </summary>
    /**/
    typedef _Key_type key_type;

    /// <summary>
    ///     The type of an element.
    /// </summary>
    /**/
    typedef typename _Mybase::value_type value_type;

    /// <summary>
    ///     The type of a mapped value associated with each key.
    /// </summary>
    /**/
    typedef _Element_type mapped_type;

    /// <summary>
    ///     The type of the hash function.
    /// </summary>
    /**/
    typedef _Hasher hasher;

    /// <summary>
    ///     The type of the comparison function.
    /// </summary>
    /**/
    typedef _Key_equality key_equal;

    /// <summary>
    ///     The type of an allocator for managing storage.
    /// </summary>
    /**/
    typedef typename _Mybase::allocator_type allocator_type;

    /// <summary>
    ///     The type of a pointer to an element.
    /// </summary>
    /**/
    typedef typename _Mybase::pointer pointer;

    /// <summary>
    ///     The type of a constant pointer to an element.
    /// </summary>
    /**/
    typedef typename _Mybase::const_pointer const_pointer;

    /// <summary>
    ///     The type of a reference to an element.
    /// </summary>
    /**/
    typedef typename _Mybase::reference reference;

    /// <summary>
    ///     The type of a constant reference to an element.
    /// </summary>
    /**/
    typedef typename _Mybase::const_reference const_reference;

    /// <summary>
    ///     The type of an unsigned distance between two elements.
    /// </summary>
    /**/
    typedef typename _Mybase::size_type size_type;

    /// <summary>
    ///     The type of a signed distance between two elements.
    /// </summary>
    /**/
    typedef typename _Mybase::difference_type difference_type;

    /// <summary>
    ///     The type of an iterator for the controlled sequence.
    /// </summary>
    /**/
    typedef typename _Mybase::iterator iterator;

    /// <summary>
    ///     The type of a constant iterator for the controlled sequence.
    /// </summary>
    /**/
    typedef typename _Mybase::const_iterator const_iterator;

    /// <summary>
    ///     The type of a bucket iterator for the controlled sequence.
    /// </summary>
    /**/
    typedef typename _Mybase::iterator local_iterator;

    /// <summary>
    ///     The type of a constant bucket iterator for the controlled sequence.
    /// </summary>
    /**/
    typedef typename _Mybase::const_iterator const_local_iterator;

    /// <summary>
    ///     Constructs a concurrent unordered map.
    /// </summary>
    /// <param name="_Number_of_buckets">
    ///     The initial number of buckets for this unordered map.
    /// </param>
    /// <param name="_Hasharg">
    ///     The hash function for this unordered map.
    /// </param>
    /// <param name="_Keyeqarg">
    ///     The equality comparison function for this unordered map.
    /// </param>
    /// <param name="_Allocator">
    ///     The allocator for this unordered map.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered map.
    ///     <para>The first constructor specifies an empty initial map and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered map.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered map <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered map <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    explicit concurrent_unordered_map(size_type _Number_of_buckets = 8, const hasher& _Hasharg = hasher(), const key_equal& _Keyeqarg = key_equal(),
        const allocator_type& _Allocator = allocator_type())
        : _Mybase(_Number_of_buckets, _Key_compare(_Hasharg, _Keyeqarg), _Allocator)
    {
        this->rehash(_Number_of_buckets);
    }

    /// <summary>
    ///     Constructs a concurrent unordered map.
    /// </summary>
    /// <param name="_Allocator">
    ///     The allocator for this unordered map.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered map.
    ///     <para>The first constructor specifies an empty initial map and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered map.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered map <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered map <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    concurrent_unordered_map(const allocator_type& _Allocator) : _Mybase(8, _Key_compare(), _Allocator)
    {
    }

    /// <summary>
    ///     Constructs a concurrent unordered map.
    /// </summary>
    /// <typeparam name="_Iterator">
    ///     The type of the input iterator.
    /// </typeparam>
    /// <param name="_Begin">
    ///     The position of the first element in the range of elements to be copied.
    /// </param>
    /// <param name="_End">
    ///     The position of the first element beyond the range of elements to be copied.
    /// </param>
    /// <param name="_Number_of_buckets">
    ///     The initial number of buckets for this unordered map.
    /// </param>
    /// <param name="_Hasharg">
    ///     The hash function for this unordered map.
    /// </param>
    /// <param name="_Keyeqarg">
    ///     The equality comparison function for this unordered map.
    /// </param>
    /// <param name="_Allocator">
    ///     The allocator for this unordered map.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered map.
    ///     <para>The first constructor specifies an empty initial map and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered map.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered map <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered map <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    template <typename _Iterator>
    concurrent_unordered_map(_Iterator _Begin, _Iterator _End, size_type _Number_of_buckets = 8, const hasher& _Hasharg = hasher(),
        const key_equal& _Keyeqarg = key_equal(), const allocator_type& _Allocator = allocator_type())
        : _Mybase(_Number_of_buckets, _Key_compare(_Hasharg, _Keyeqarg), _Allocator)
    {
        this->rehash(_Number_of_buckets);
        for (; _Begin != _End; ++_Begin)
        {
            this->_Insert(*_Begin);
        }
    }

    /// <summary>
    ///     Constructs a concurrent unordered map.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_map</c> object to copy or move elements from.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered map.
    ///     <para>The first constructor specifies an empty initial map and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered map.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered map <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered map <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    concurrent_unordered_map(const concurrent_unordered_map& _Umap) : _Mybase(_Umap)
    {
    }

    /// <summary>
    ///     Constructs a concurrent unordered map.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_map</c> object to copy or move elements from.
    /// </param>
    /// <param name="_Allocator">
    ///     The allocator for this unordered map.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered map.
    ///     <para>The first constructor specifies an empty initial map and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered map.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered map <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered map <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    concurrent_unordered_map(const concurrent_unordered_map& _Umap, const allocator_type& _Allocator) : _Mybase(_Umap, _Allocator)
    {
    }

    /// <summary>
    ///     Constructs a concurrent unordered map.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_map</c> object to copy or move elements from.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered map.
    ///     <para>The first constructor specifies an empty initial map and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered map.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered map <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered map <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    concurrent_unordered_map(concurrent_unordered_map&& _Umap) : _Mybase(::std::move(_Umap))
    {
    }

    /// <summary>
    ///     Assigns the contents of another <c>concurrent_unordered_map</c> object to this one. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_map</c> object.
    /// </param>
    /// <returns>
    ///     A reference to this <c>concurrent_unordered_map</c> object.
    /// </returns>
    /// <remarks>
    ///     After erasing any existing elements a concurrent vector, <c>operator=</c> either copies or moves the contents of <paramref name="_Umap"/> into
    ///     the concurrent vector.
    /// </remarks>
    /**/
    concurrent_unordered_map& operator=(const concurrent_unordered_map& _Umap)
    {
        _Mybase::operator=(_Umap);
        return (*this);
    }

    /// <summary>
    ///     Assigns the contents of another <c>concurrent_unordered_map</c> object to this one. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_map</c> object.
    /// </param>
    /// <returns>
    ///     A reference to this <c>concurrent_unordered_map</c> object.
    /// </returns>
    /// <remarks>
    ///     After erasing any existing elements in a concurrent vector, <c>operator=</c> either copies or moves the contents of <paramref name="_Umap"/> into
    ///     the concurrent vector.
    /// </remarks>
    /**/
    concurrent_unordered_map& operator=(concurrent_unordered_map&& _Umap)
    {
        _Mybase::operator=(::std::move(_Umap));
        return (*this);
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_map</c> object.
    /// </summary>
    /// <param name="_Value">
    ///     The value to be inserted.
    /// </param>
    /// <returns>
    ///     A pair that contains an iterator and a boolean value. See the Remarks section for more details.
    /// </returns>
    /// <remarks>
    ///     The first member function determines whether an element X exists in the sequence whose key has equivalent ordering to
    ///     that of <paramref name="_Value"/>. If not, it creates such an element X and initializes it with <paramref name="_Value"/>.
    ///     The function then determines the iterator <c>where</c> that designates X. If an insertion occurred, the function returns
    ///     <c>std::pair(where, true)</c>. Otherwise, it returns <c>std::pair(where, false)</c>.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    ::std::pair<iterator, bool> insert(const value_type& _Value)
    {
        return this->_Insert(_Value);
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_map</c> object.
    /// </summary>
    /// <param name="_Where">
    ///     The starting location to search for an insertion point.
    /// </param>
    /// <param name="_Value">
    ///     The value to be inserted.
    /// </param>
    /// <returns>
    ///     An iterator pointing to the insertion location of the object.  If the key already exists in the container
    ///     an iterator pointing to the duplicate key location in the map is returned.
    /// </returns>
    /// <remarks>
    ///     The first member function determines whether an element X exists in the sequence whose key has equivalent ordering to
    ///     that of <paramref name="_Value"/>. If not, it creates such an element X and initializes it with <paramref name="_Value"/>.
    ///     The function then determines the iterator <c>where</c> that designates X. If an insertion occurred, the function returns
    ///     <c>std::pair(where, true)</c>. Otherwise, it returns <c>std::pair(where, false)</c>.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    iterator insert(const_iterator _Where, const value_type& _Value)
    {
        // Current implementation ignores the hint. The method is provided for compatibility with unordered_map.
        return this->_Insert(_Value).first;
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_map</c> object.
    /// </summary>
    /// <typeparam name="_Iterator">
    ///     The iterator type used for insertion.
    /// </typeparam>
    /// <param name="_First">
    ///     The beginning of the range to insert.
    /// </param>
    /// <param name="_Last">
    ///     The end of the range to insert.
    /// </param>
    /// <remarks>
    ///     The first member function determines whether an element X exists in the sequence whose key has equivalent ordering to
    ///     that of <paramref name="_Value"/>. If not, it creates such an element X and initializes it with <paramref name="_Value"/>.
    ///     The function then determines the iterator <c>where</c> that designates X. If an insertion occurred, the function returns
    ///     <c>std::pair(where, true)</c>. Otherwise, it returns <c>std::pair(where, false)</c>.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    template<class _Iterator>
    void insert(_Iterator _First, _Iterator _Last)
    {
        this->_Insert(_First, _Last);
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_map</c> object.
    /// </summary>
    /// <typeparam name="_Valty">
    ///     The type of the value inserted into the map.
    /// </typeparam>
    /// <param name="_Value">
    ///     The value to be inserted.
    /// </param>
    /// <returns>
    ///     A pair that contains an iterator and a boolean value. See the Remarks section for more details.
    /// </returns>
    /// <remarks>
    ///     The first member function determines whether an element X exists in the sequence whose key has equivalent ordering to
    ///     that of <paramref name="_Value"/>. If not, it creates such an element X and initializes it with <paramref name="_Value"/>.
    ///     The function then determines the iterator <c>where</c> that designates X. If an insertion occurred, the function returns
    ///     <c>std::pair(where, true)</c>. Otherwise, it returns <c>std::pair(where, false)</c>.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    template<class _Valty>
    ::std::pair<iterator, bool> insert(_Valty&& _Value)
    {
        return this->_Insert(::std::forward<_Valty>(_Value));
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_map</c> object.
    /// </summary>
    /// <typeparam name="_Valty">
    ///     The type of the value inserted into the map.
    /// </typeparam>
    /// <param name="_Where">
    ///     The starting location to search for an insertion point.
    /// </param>
    /// <param name="_Value">
    ///     The value to be inserted.
    /// </param>
    /// <returns>
    ///     An iterator pointing to the insertion location of the object.  If the key already exists in the container
    ///     an iterator pointing to the duplicate key location in the map is returned.
    /// </returns>
    /// <remarks>
    ///     The first member function determines whether an element X exists in the sequence whose key has equivalent ordering to
    ///     that of <paramref name="_Value"/>. If not, it creates such an element X and initializes it with <paramref name="_Value"/>.
    ///     The function then determines the iterator <c>where</c> that designates X. If an insertion occurred, the function returns
    ///     <c>std::pair(where, true)</c>. Otherwise, it returns <c>std::pair(where, false)</c>.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    template<class _Valty>
        ::std::enable_if_t<!::std::is_same_v<const_iterator,
            ::std::remove_reference_t<_Valty>>, iterator>
    insert(const_iterator _Where, _Valty&& _Value)
    {
        // Current implementation ignores the hint. The method is provided for compatibility with unordered_map.
        return this->_Insert(::std::forward<_Valty>(_Value)).first;
    }

    /// <summary>
    ///     Removes elements from the <c>concurrent_unordered_map</c> at specified positions. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Where">
    ///     The iterator position to erase from.
    /// </param>
    /// <remarks>
    ///     The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
    ///     member function removes the elements in the range [<paramref name="_Begin"/>, <paramref name="_End"/>).
    ///     <para>The third member function removes the elements in the range delimited by <see cref="concurrent_unordered_map::equal_range Method">
    ///     concurrent_unordered_map::equal_range</see>(_Keyval). </para>
    /// </remarks>
    /// <returns>
    ///     The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
    ///     or <see cref="concurrent_unordered_map::end Method"> concurrent_unordered_map::end</see>() if no such element exists. The third
    ///     member function returns the number of elements it removes.
    /// </returns>
    /**/
    iterator unsafe_erase(const_iterator _Where)
    {
        return _Mybase::unsafe_erase(_Where);
    }

    /// <summary>
    ///     Removes elements from the <c>concurrent_unordered_map</c> at specified positions. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Begin">
    ///     The position of the first element in the range of elements to be erased.
    /// </param>
    /// <param name="_End">
    ///     The position of the first element beyond the range of elements to be erased.
    /// </param>
    /// <remarks>
    ///     The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
    ///     member function removes the elements in the range [<paramref name="_Begin"/>, <paramref name="_End"/>).
    ///     <para>The third member function removes the elements in the range delimited by <see cref="concurrent_unordered_map::equal_range Method">
    ///     concurrent_unordered_map::equal_range</see>(_Keyval). </para>
    /// </remarks>
    /// <returns>
    ///     The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
    ///     or <see cref="concurrent_unordered_map::end Method"> concurrent_unordered_map::end</see>() if no such element exists. The third
    ///     member function returns the number of elements it removes.
    /// </returns>
    /**/
    iterator unsafe_erase(const_iterator _Begin, const_iterator _End)
    {
        return _Mybase::unsafe_erase(_Begin, _End);
    }

    /// <summary>
    ///     Removes elements from the <c>concurrent_unordered_map</c> at specified positions. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Keyval">
    ///     The key value to erase.
    /// </param>
    /// <remarks>
    ///     The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
    ///     member function removes the elements in the range [<paramref name="_Begin"/>, <paramref name="_End"/>).
    ///     <para>The third member function removes the elements in the range delimited by <see cref="concurrent_unordered_map::equal_range Method">
    ///     concurrent_unordered_map::equal_range</see>(_Keyval). </para>
    /// </remarks>
    /// <returns>
    ///     The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
    ///     or <see cref="concurrent_unordered_map::end Method"> concurrent_unordered_map::end</see>() if no such element exists. The third
    ///     member function returns the number of elements it removes.
    /// </returns>
    /**/
    size_type unsafe_erase(const key_type& _Keyval)
    {
        return _Mybase::unsafe_erase(_Keyval);
    }

    /// <summary>
    ///     Swaps the contents of two <c>concurrent_unordered_map</c> objects. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Umap">
    ///     The <c>concurrent_unordered_map</c> object to swap with.
    /// </param>
    /**/
    void swap(concurrent_unordered_map& _Umap)
    {
        _Mybase::swap(_Umap);
    }

    /// <summary>
    ///     Gets the stored hash function object.
    /// </summary>
    /// <returns>
    ///     The stored hash function object.
    /// </returns>
    /**/
    hasher hash_function() const
    {
        return this->_M_comparator._M_hash_object;
    }

    /// <summary>
    ///     Gets the stored equality comparison function object.
    /// </summary>
    /// <returns>
    ///     The stored equality comparison function object.
    /// </returns>
    /**/
    key_equal key_eq() const
    {
        return this->_M_comparator._M_key_compare_object;
    }

    /// <summary>
    ///     Finds or inserts an element with the specified key. This method is concurrency-safe.
    /// </summary>
    /// <param name="_Keyval">
    ///     The key value to find or insert.
    /// </param>
    /// <returns>
    ///     A reference to the data value of the found or inserted element.
    /// </returns>
    /// <remarks>
    ///     If the argument key value is not found, then it is inserted along with the default value of the data type.
    ///     <para> <c>operator[]</c> may be used to insert elements into a map <c>m</c> using <c>m[_Key] = DataValue;</c>, where
    ///     <c>DataValue</c> is the value of the <c>mapped_type</c> of the element with a key value of <c>_Key</c>.</para>
    ///     <para> When using <c>operator[]</c> to insert elements, the returned reference does not indicate whether an insertion
    ///     is changing a pre-existing element or creating a new one. The member functions <see cref="concurrent_unordered_map::find Method">
    ///     find</see> and <see cref="concurrent_unordered_map::insert Method">insert</see> can be used to determine whether an element
    ///     with a specified key is already present before an insertion.</para>
    /// </remarks>
    /**/
    mapped_type& operator[](const key_type& _Keyval)
    {
        iterator _Where = this->find(_Keyval);

        if (_Where == this->end())
        {
            _Where = this->_Insert(::std::make_pair(_Keyval, mapped_type())).first;
        }

        return ((*_Where).second);
    }

    /// <summary>
    ///     Finds or inserts an element with the specified key. This method is concurrency-safe.
    /// </summary>
    /// <param name="_Keyval">
    ///     The key value to find or insert.
    /// </param>
    /// <returns>
    ///     A reference to the data value of the found or inserted element.
    /// </returns>
    /// <remarks>
    ///     If the argument key value is not found, then it is inserted along with the default value of the data type.
    ///     <para> <c>operator[]</c> may be used to insert elements into a map <c>m</c> using <c>m[_Key] = DataValue;</c>, where
    ///     <c>DataValue</c> is the value of the <c>mapped_type</c> of the element with a key value of <c>_Key</c>.</para>
    ///     <para> When using <c>operator[]</c> to insert elements, the returned reference does not indicate whether an insertion
    ///     is changing a pre-existing element or creating a new one. The member functions <see cref="concurrent_unordered_map::find Method">
    ///     find</see> and <see cref="concurrent_unordered_map::insert Method">insert</see> can be used to determine whether an element
    ///     with a specified key is already present before an insertion.</para>
    /// </remarks>
    /**/
    mapped_type& operator[](key_type && _Keyval)
    {
        iterator _Where = this->find(_Keyval);

        if (_Where == this->end())
        {
            _Where = this->_Insert(::std::make_pair(::std::forward<key_type>(_Keyval), mapped_type())).first;
        }

        return ((*_Where).second);
    }

    /// <summary>
    ///     Finds an element in a <c>concurrent_unordered_map</c> with a specified key value.. This method is concurrency-safe.
    /// </summary>
    /// <param name="_Keyval">
    ///     The key value to find.
    /// </param>
    /// <returns>
    ///     A reference to the data value of the element found.
    /// </returns>
    /// <remarks>
    ///     If the argument key value is not found, the function throws an object of class <c>out_of_range</c>.
    /// </remarks>
    /**/
    mapped_type& at(const key_type& _Keyval)
    {
        iterator _Where = this->find(_Keyval);

        if (_Where == this->end())
        {
            _STD _Xout_of_range("invalid concurrent_unordered_map<K, T> key");
        }

        return ((*_Where).second);
    }

    /// <summary>
    ///     Finds an element in a <c>concurrent_unordered_map</c> with a specified key value.. This method is concurrency-safe.
    /// </summary>
    /// <param name="_Keyval">
    ///     The key value to find.
    /// </param>
    /// <returns>
    ///     A reference to the data value of the element found.
    /// </returns>
    /// <remarks>
    ///     If the argument key value is not found, the function throws an object of class <c>out_of_range</c>.
    /// </remarks>
    /**/
    const mapped_type& at(const key_type& _Keyval) const
    {
        const_iterator _Where = this->find(_Keyval);

        if (_Where == this->end())
        {
            _STD _Xout_of_range("invalid concurrent_unordered_map<K, T> key");
        }

        return ((*_Where).second);
    }
};

/// <summary>
///     The <c>concurrent_unordered_multimap</c> class is an concurrency-safe container that controls a varying-length sequence of
///     elements of type <c>std::pair&lt;const _Key_type, _Element_type&gt;</c>. The sequence is represented in a way that enables
///     concurrency-safe append, element access, iterator access and iterator traversal operations.
/// </summary>
/// <typeparam name="_Key_type">
///     The key type.
/// </typeparam>
/// <typeparam name="_Element_type">
///     The mapped type.
/// </typeparam>
/// <typeparam name="_Hasher">
///     The hash function object type. This argument is optional and the default value is
///     <c>std::hash&lt;</c><typeparamref name="_Key_type"/><c>&gt;</c>.
/// </typeparam>
/// <typeparam name="_Key_equality">
///     The equality comparison function object type. This argument is optional and the default value is
///     <c>std::equal_to&lt;</c><typeparamref name="_Key_type"/><c>&gt;</c>.
/// </typeparam>
/// <typeparam name="_Allocator_type">
///     The type that represents the stored allocator object that encapsulates details about the allocation and
///     deallocation of memory for the concurrent vector. This argument is optional and the default value is
///     <c>std::allocator&lt;std::pair&lt;</c><typeparamref name="_Key_type"/>, <typeparamref name="_Element_type"/><c>&gt;&gt;</c>.
/// </typeparam>
/// <remarks>
///     For detailed information on the <c>concurrent_unordered_multimap</c> class, see <see cref="Parallel Containers and Objects"/>.
/// </remarks>
/// <seealso cref="Parallel Containers and Objects"/>
/**/
template <typename _Key_type, typename _Element_type, typename _Hasher = ::std::hash<_Key_type>, typename _Key_equality = ::std::equal_to<_Key_type>, typename _Allocator_type = ::std::allocator<::std::pair<const _Key_type, _Element_type>>>
class concurrent_unordered_multimap : public details::_Concurrent_hash< details::_Concurrent_unordered_map_traits<_Key_type, _Element_type, details::_Hash_compare<_Key_type, _Hasher, _Key_equality>, _Allocator_type, true>>
{
public:
    // Base type definitions
    typedef concurrent_unordered_multimap<_Key_type, _Element_type, _Hasher, _Key_equality, _Allocator_type> _Mytype;
    typedef details::_Hash_compare<_Key_type, _Hasher, _Key_equality> _Key_compare;
    typedef details::_Concurrent_hash< details::_Concurrent_unordered_map_traits<_Key_type, _Element_type, _Key_compare, _Allocator_type, true>> _Mybase;

    /// <summary>
    ///     The type of an ordering key.
    /// </summary>
    /**/
    typedef _Key_type key_type;

    /// <summary>
    ///     The type of an element.
    /// </summary>
    /**/
    typedef typename _Mybase::value_type value_type;

    /// <summary>
    ///     The type of a mapped value associated with each key.
    /// </summary>
    /**/
    typedef _Element_type mapped_type;

    /// <summary>
    ///     The type of the hash function.
    /// </summary>
    /**/
    typedef _Hasher hasher;

    /// <summary>
    ///     The type of the comparison function.
    /// </summary>
    /**/
    typedef _Key_equality key_equal;

    /// <summary>
    ///     The type of an allocator for managing storage.
    /// </summary>
    /**/
    typedef typename _Mybase::allocator_type allocator_type;

    /// <summary>
    ///     The type of a pointer to an element.
    /// </summary>
    /**/
    typedef typename _Mybase::pointer pointer;

    /// <summary>
    ///     The type of a constant pointer to an element.
    /// </summary>
    /**/
    typedef typename _Mybase::const_pointer const_pointer;

    /// <summary>
    ///     The type of a reference to an element.
    /// </summary>
    /**/
    typedef typename _Mybase::reference reference;

    /// <summary>
    ///     The type of a constant reference to an element.
    /// </summary>
    /**/
    typedef typename _Mybase::const_reference const_reference;

    /// <summary>
    ///     The type of an unsigned distance between two elements.
    /// </summary>
    /**/
    typedef typename _Mybase::size_type size_type;

    /// <summary>
    ///     The type of a signed distance between two elements.
    /// </summary>
    /**/
    typedef typename _Mybase::difference_type difference_type;

    /// <summary>
    ///     The type of an iterator for the controlled sequence.
    /// </summary>
    /**/
    typedef typename _Mybase::iterator iterator;

    /// <summary>
    ///     The type of a constant iterator for the controlled sequence.
    /// </summary>
    /**/
    typedef typename _Mybase::const_iterator const_iterator;

    /// <summary>
    ///     The type of a bucket iterator for the controlled sequence.
    /// </summary>
    /**/
    typedef typename _Mybase::iterator local_iterator;

    /// <summary>
    ///     The type of a constant bucket iterator for the controlled sequence.
    /// </summary>
    /**/
    typedef typename _Mybase::const_iterator const_local_iterator;

    /// <summary>
    ///     Constructs a concurrent unordered multimap.
    /// </summary>
    /// <param name="_Number_of_buckets">
    ///     The initial number of buckets for this unordered multimap.
    /// </param>
    /// <param name="_Hasharg">
    ///     The hash function for this unordered multimap.
    /// </param>
    /// <param name="_Keyeqarg">
    ///     The equality comparison function for this unordered multimap.
    /// </param>
    /// <param name="_Allocator">
    ///     The allocator for this unordered multimap.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered multimap.
    ///     <para>The first constructor specifies an empty initial multimap and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered multimap.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    explicit concurrent_unordered_multimap(size_type _Number_of_buckets = 8, const hasher& _Hasharg = hasher(), const key_equal& _Keyeqarg = key_equal(),
        const allocator_type& _Allocator = allocator_type())
        : _Mybase(_Number_of_buckets, _Key_compare(_Hasharg, _Keyeqarg), _Allocator)
    {
        this->rehash(_Number_of_buckets);
    }

    /// <summary>
    ///     Constructs a concurrent unordered multimap.
    /// </summary>
    /// <param name="_Allocator">
    ///     The allocator for this unordered multimap.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered multimap.
    ///     <para>The first constructor specifies an empty initial multimap and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered multimap.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    concurrent_unordered_multimap(const allocator_type& _Allocator) : _Mybase(8, _Key_compare(), _Allocator)
    {
    }

    /// <summary>
    ///     Constructs a concurrent unordered multimap.
    /// </summary>
    /// <typeparam name="_Iterator">
    ///     The type of the input iterator.
    /// </typeparam>
    /// <param name="_Begin">
    ///     The position of the first element in the range of elements to be copied.
    /// </param>
    /// <param name="_End">
    ///     The position of the first element beyond the range of elements to be copied.
    /// </param>
    /// <param name="_Number_of_buckets">
    ///     The initial number of buckets for this unordered multimap.
    /// </param>
    /// <param name="_Hasharg">
    ///     The hash function for this unordered multimap.
    /// </param>
    /// <param name="_Keyeqarg">
    ///     The equality comparison function for this unordered multimap.
    /// </param>
    /// <param name="_Allocator">
    ///     The allocator for this unordered multimap.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered multimap.
    ///     <para>The first constructor specifies an empty initial multimap and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered multimap.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    template <typename _Iterator>
    concurrent_unordered_multimap(_Iterator _Begin, _Iterator _End, size_type _Number_of_buckets = 8, const hasher& _Hasharg = hasher(),
        const key_equal& _Keyeqarg = key_equal(), const allocator_type& _Allocator = allocator_type())
        : _Mybase(_Number_of_buckets, _Key_compare(_Hasharg, _Keyeqarg), _Allocator)
    {
        this->rehash(_Number_of_buckets);
        for (; _Begin != _End; ++_Begin)
        {
            this->_Insert(*_Begin);
        }
    }

    /// <summary>
    ///     Constructs a concurrent unordered multimap.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_multimap</c> object to copy elements from.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered multimap.
    ///     <para>The first constructor specifies an empty initial multimap and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered multimap.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    concurrent_unordered_multimap(const concurrent_unordered_multimap& _Umap) : _Mybase(_Umap)
    {
    }

    /// <summary>
    ///     Constructs a concurrent unordered multimap.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_multimap</c> object to copy elements from.
    /// </param>
    /// <param name="_Allocator">
    ///     The allocator for this unordered multimap.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered multimap.
    ///     <para>The first constructor specifies an empty initial multimap and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered multimap.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    concurrent_unordered_multimap(const concurrent_unordered_multimap& _Umap, const allocator_type& _Allocator) : _Mybase(_Umap, _Allocator)
    {
    }

    /// <summary>
    ///     Constructs a concurrent unordered multimap.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_multimap</c> object to copy elements from.
    /// </param>
    /// <remarks>
    ///     All constructors store an allocator object <paramref name="_Allocator"/> and initialize the unordered multimap.
    ///     <para>The first constructor specifies an empty initial multimap and explicitly specifies the number of buckets,
    ///     hash function, equality function and allocator type to be used.</para>
    ///     <para>The second constructor specifies an allocator for the unordered multimap.</para>
    ///     <para>The third constructor specifies values supplied by the iterator range [<paramref name="_Begin"/>, <paramref name="_End"/>).</para>
    ///     <para>The fourth and fifth constructors specify a copy of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    ///     <para>The last constructor specifies a move of the concurrent unordered multimap <paramref name="_Umap"/>.</para>
    /// </remarks>
    /**/
    concurrent_unordered_multimap(concurrent_unordered_multimap&& _Umap) : _Mybase(::std::move(_Umap))
    {
    }

    /// <summary>
    ///     Assigns the contents of another <c>concurrent_unordered_multimap</c> object to this one. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_multimap</c> object.
    /// </param>
    /// <returns>
    ///     A reference to this <c>concurrent_unordered_multimap</c> object.
    /// </returns>
    /// <remarks>
    ///     After erasing any existing elements in a concurrent unordered multimap, <c>operator=</c> either copies or moves the contents of
    ///     <paramref name="_Umap"/> into the concurrent unordered multimap.
    /// </remarks>
    /**/
    concurrent_unordered_multimap& operator=(const concurrent_unordered_multimap& _Umap)
    {
        _Mybase::operator=(_Umap);
        return (*this);
    }

    /// <summary>
    ///     Assigns the contents of another <c>concurrent_unordered_multimap</c> object to this one. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Umap">
    ///     The source <c>concurrent_unordered_multimap</c> object.
    /// </param>
    /// <returns>
    ///     A reference to this <c>concurrent_unordered_multimap</c> object.
    /// </returns>
    /// <remarks>
    ///     After erasing any existing elements in a concurrent unordered multimap, <c>operator=</c> either copies or moves the contents of
    ///     <paramref name="_Umap"/> into the concurrent unordered multimap.
    /// </remarks>
    /**/
    concurrent_unordered_multimap& operator=(concurrent_unordered_multimap&& _Umap)
    {
        _Mybase::operator=(::std::move(_Umap));
        return (*this);
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_multimap</c> object.
    /// </summary>
    /// <param name="_Value">
    ///     The value to be inserted.
    /// </param>
    /// <returns>
    ///     An iterator pointing to the insertion location.
    /// </returns>
    /// <remarks>
    ///     The first member function inserts the element <paramref name="_Value"/> in the controlled sequence, then returns the iterator
    ///     that designates the inserted element.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    iterator insert(const value_type& _Value)
    {
        return this->_Insert(_Value).first;
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_multimap</c> object.
    /// </summary>
    /// <param name="_Where">
    ///     The starting location to search for an insertion point.
    /// </param>
    /// <param name="_Value">
    ///     The value to be inserted.
    /// </param>
    /// <returns>
    ///     An iterator pointing to the insertion location.
    /// </returns>
    /// <remarks>
    ///     The first member function inserts the element <paramref name="_Value"/> in the controlled sequence, then returns the iterator
    ///     that designates the inserted element.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    iterator insert(const_iterator _Where, const value_type& _Value)
    {
        // Current implementation ignores the hint. The method is provided for compatibility with unordered_multimap.
        return this->_Insert(_Value).first;
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_multimap</c> object.
    /// </summary>
    /// <typeparam name="_Iterator">
    ///     The iterator type used for insertion.
    /// </typeparam>
    /// <param name="_First">
    ///     The beginning of the range to insert.
    /// </param>
    /// <param name="_Last">
    ///     The end of the range to insert.
    /// </param>
    /// <remarks>
    ///     The first member function inserts the element <paramref name="_Value"/> in the controlled sequence, then returns the iterator
    ///     that designates the inserted element.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    template<class _Iterator>
    void insert(_Iterator _First, _Iterator _Last)
    {
        this->_Insert(_First, _Last);
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_multimap</c> object.
    /// </summary>
    /// <typeparam name="_Valty">
    ///     The type of the value inserted into the map.
    /// </typeparam>
    /// <param name="_Value">
    ///     The value to be inserted.
    /// </param>
    /// <returns>
    ///     An iterator pointing to the insertion location.
    /// </returns>
    /// <remarks>
    ///     The first member function inserts the element <paramref name="_Value"/> in the controlled sequence, then returns the iterator
    ///     that designates the inserted element.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    template<class _Valty>
    iterator insert(_Valty&& _Value)
    {
        return this->_Insert(::std::forward<_Valty>(_Value)).first;
    }

    /// <summary>
    ///     Adds elements to the <c>concurrent_unordered_multimap</c> object.
    /// </summary>
    /// <typeparam name="_Valty">
    ///     The type of the value inserted into the map.
    /// </typeparam>
    /// <param name="_Where">
    ///     The starting location to search for an insertion point.
    /// </param>
    /// <param name="_Value">
    ///     The value to be inserted.
    /// </param>
    /// <returns>
    ///     An iterator pointing to the insertion location.
    /// </returns>
    /// <remarks>
    ///     The first member function inserts the element <paramref name="_Value"/> in the controlled sequence, then returns the iterator
    ///     that designates the inserted element.
    ///     <para>The second member function returns insert(<paramref name="_Value"/>), using <paramref name="_Where"/> as a starting
    ///     place within the controlled sequence to search for the insertion point.</para>
    ///     <para>The third member function inserts the sequence of element values from the range [<paramref name="_First"/>,
    ///     <paramref name="_Last"/>).</para>
    ///     <para>The last two member functions behave the same as the first two, except that <paramref name="_Value"/> is used to
    ///     construct the inserted value.</para>
    /// </remarks>
    /**/
    template<class _Valty>
        ::std::enable_if_t<!::std::is_same_v<const_iterator, ::std::remove_reference_t<_Valty>>, iterator>
    insert(const_iterator _Where, _Valty&& _Value)
    {
        // Current implementation ignores the hint. The method is provided for compatibility with unordered_multimap.
        return this->_Insert(::std::forward<_Valty>(_Value)).first;
    }

    /// <summary>
    ///     Removes elements from the <c>concurrent_unordered_multimap</c> at specified positions. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Where">
    ///     The iterator position to erase from.
    /// </param>
    /// <remarks>
    ///     The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
    ///     member function removes the elements in the range [<paramref name="_Begin"/>, <paramref name="_End"/>).
    ///     <para>The third member function removes the elements in the range delimited by <see cref="concurrent_unordered_multimap::equal_range Method">
    ///     concurrent_unordered_multimap::equal_range</see>(_Keyval). </para>
    /// </remarks>
    /// <returns>
    ///     The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
    ///     or <see cref="concurrent_unordered_multimap::end Method">concurrent_unordered_multimap::end</see>() if no such element exists. The third
    ///     member function returns the number of elements it removes.
    /// </returns>
    /**/
    iterator unsafe_erase(const_iterator _Where)
    {
        return _Mybase::unsafe_erase(_Where);
    }

    /// <summary>
    ///     Removes elements from the <c>concurrent_unordered_multimap</c> at specified positions. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Keyval">
    ///     The key value to erase.
    /// </param>
    /// <remarks>
    ///     The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
    ///     member function removes the elements in the range [<paramref name="_Begin"/>, <paramref name="_End"/>).
    ///     <para>The third member function removes the elements in the range delimited by <see cref="concurrent_unordered_multimap::equal_range Method">
    ///     concurrent_unordered_multimap::equal_range</see>(_Keyval). </para>
    /// </remarks>
    /// <returns>
    ///     The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
    ///     or <see cref="concurrent_unordered_multimap::end Method">concurrent_unordered_multimap::end</see>() if no such element exists. The third
    ///     member function returns the number of elements it removes.
    /// </returns>
    /**/
    size_type unsafe_erase(const key_type& _Keyval)
    {
        return _Mybase::unsafe_erase(_Keyval);
    }

    /// <summary>
    ///     Removes elements from the <c>concurrent_unordered_multimap</c> at specified positions. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Begin">
    ///     Position of the first element in the range of elements to be erased.
    /// </param>
    /// <param name="_End">
    ///     Position of the first element beyond the range of elements to be erased.
    /// </param>
    /// <remarks>
    ///     The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
    ///     member function removes the elements in the range [<paramref name="_Begin"/>, <paramref name="_End"/>).
    ///     <para>The third member function removes the elements in the range delimited by <see cref="concurrent_unordered_multimap::equal_range Method">
    ///     concurrent_unordered_multimap::equal_range</see>(_Keyval). </para>
    /// </remarks>
    /// <returns>
    ///     The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
    ///     or <see cref="concurrent_unordered_multimap::end Method">concurrent_unordered_multimap::end</see>() if no such element exists. The third
    ///     member function returns the number of elements it removes.
    /// </returns>
    /**/
    iterator unsafe_erase(const_iterator _First, const_iterator _Last)
    {
        return _Mybase::unsafe_erase(_First, _Last);
    }

    /// <summary>
    ///     Swaps the contents of two <c>concurrent_unordered_multimap</c> objects. This method is not concurrency-safe.
    /// </summary>
    /// <param name="_Umap">
    ///     The <c>concurrent_unordered_multimap</c> object to swap with.
    /// </param>
    /**/
    void swap(concurrent_unordered_multimap& _Umap)
    {
        _Mybase::swap(_Umap);
    }

    /// <summary>
    ///     Returns the stored hash function object.
    /// </summary>
    /// <returns>
    ///     The stored hash function object.
    /// </returns>
    /**/
    hasher hash_function() const
    {
        return this->_M_comparator._M_hash_object;
    }

    /// <summary>
    ///     Returns the stored equality comparison function object.
    /// </summary>
    /// <returns>
    ///     The stored equality comparison function object.
    /// </returns>
    /**/
    key_equal key_eq() const
    {
        return this->_M_comparator._M_key_compare_object;
    }
};
} // namespace Concurrency

namespace concurrency = ::Concurrency;

#pragma warning(pop)
#pragma pack(pop)