unordered_set

Go to the documentation of this file.

// Debugging unordered_set/unordered_multiset implementation -*- C++ -*-

// Copyright (C) 2003-2015 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file debug/unordered_set
 *  This file is a GNU debug extension to the Standard C++ Library.
 */

#ifndef _GLIBCXX_DEBUG_UNORDERED_SET
#define _GLIBCXX_DEBUG_UNORDERED_SET 1

#if __cplusplus < 201103L
# include <bits/c++0x_warning.h>
#else
# include <unordered_set>

#include <debug/safe_unordered_container.h>
#include <debug/safe_container.h>
#include <debug/safe_iterator.h>
#include <debug/safe_local_iterator.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
namespace __debug
{
  /// Class std::unordered_set with safety/checking/debug instrumentation.
  template<typename _Value,
           typename _Hash = std::hash<_Value>,
           typename _Pred = std::equal_to<_Value>,
           typename _Alloc = std::allocator<_Value> >
    class unordered_set
    : public __gnu_debug::_Safe_container<
        unordered_set<_Value, _Hash, _Pred, _Alloc>, _Alloc,
        __gnu_debug::_Safe_unordered_container>,
      public _GLIBCXX_STD_C::unordered_set<_Value, _Hash, _Pred, _Alloc>
    {
      typedef _GLIBCXX_STD_C::unordered_set<
        _Value, _Hash, _Pred, _Alloc>                                   _Base;
      typedef __gnu_debug::_Safe_container<
        unordered_set, _Alloc, __gnu_debug::_Safe_unordered_container>  _Safe;

      typedef typename _Base::const_iterator       _Base_const_iterator;
      typedef typename _Base::iterator             _Base_iterator;
      typedef typename _Base::const_local_iterator _Base_const_local_iterator;
      typedef typename _Base::local_iterator       _Base_local_iterator;

    public:
      typedef typename _Base::size_type                 size_type;
      typedef typename _Base::hasher                    hasher;
      typedef typename _Base::key_equal                 key_equal;
      typedef typename _Base::allocator_type            allocator_type;

      typedef typename _Base::key_type                  key_type;
      typedef typename _Base::value_type                value_type;

      typedef __gnu_debug::_Safe_iterator<
        _Base_iterator, unordered_set>                  iterator;
      typedef __gnu_debug::_Safe_iterator<
        _Base_const_iterator, unordered_set>            const_iterator;
      typedef __gnu_debug::_Safe_local_iterator<
        _Base_local_iterator, unordered_set>            local_iterator;
      typedef __gnu_debug::_Safe_local_iterator<
        _Base_const_local_iterator, unordered_set>      const_local_iterator;

      unordered_set() = default;

      explicit
      unordered_set(size_type __n,
                    const hasher& __hf = hasher(),
                    const key_equal& __eql = key_equal(),
                    const allocator_type& __a = allocator_type())
      : _Base(__n, __hf, __eql, __a) { }

      template<typename _InputIterator>
        unordered_set(_InputIterator __first, _InputIterator __last,
                      size_type __n = 0,
                      const hasher& __hf = hasher(),
                      const key_equal& __eql = key_equal(),
                      const allocator_type& __a = allocator_type())
        : _Base(__gnu_debug::__base(__gnu_debug::__check_valid_range(__first,
                                                                     __last)),
                __gnu_debug::__base(__last), __n,
                __hf, __eql, __a) { }

      unordered_set(const unordered_set&) = default;

      unordered_set(const _Base& __x)
      : _Base(__x) { }

      unordered_set(unordered_set&&) = default;

      explicit
      unordered_set(const allocator_type& __a)
      : _Base(__a) { }

      unordered_set(const unordered_set& __uset,
                    const allocator_type& __a)
      : _Base(__uset, __a) { }

      unordered_set(unordered_set&& __uset,
                    const allocator_type& __a)
      : _Safe(std::move(__uset._M_safe()), __a),
        _Base(std::move(__uset._M_base()), __a) { }

      unordered_set(initializer_list<value_type> __l,
                    size_type __n = 0,
                    const hasher& __hf = hasher(),
                    const key_equal& __eql = key_equal(),
                    const allocator_type& __a = allocator_type())
      : _Base(__l, __n, __hf, __eql, __a) { }

      ~unordered_set() = default;

      unordered_set&
      operator=(const unordered_set&) = default;

      unordered_set&
      operator=(unordered_set&&) = default;

      unordered_set&
      operator=(initializer_list<value_type> __l)
      {
        _M_base() = __l;
        this->_M_invalidate_all();
        return *this;
      }

      void
      swap(unordered_set& __x)
        noexcept( noexcept(declval<_Base>().swap(__x)) )
      {
        _Safe::_M_swap(__x);
        _Base::swap(__x);
      }

      void
      clear() noexcept
      {
        _Base::clear();
        this->_M_invalidate_all();
      }

      iterator
      begin() noexcept
      { return iterator(_Base::begin(), this); }

      const_iterator
      begin() const noexcept
      { return const_iterator(_Base::begin(), this); }

      iterator
      end() noexcept
      { return iterator(_Base::end(), this); }

      const_iterator
      end() const noexcept
      { return const_iterator(_Base::end(), this); }

      const_iterator
      cbegin() const noexcept
      { return const_iterator(_Base::begin(), this); }

      const_iterator
      cend() const noexcept
      { return const_iterator(_Base::end(), this); }

      // local versions
      local_iterator
      begin(size_type __b)
      {
        __glibcxx_check_bucket_index(__b);
        return local_iterator(_Base::begin(__b), this);
      }

      local_iterator
      end(size_type __b)
      {
        __glibcxx_check_bucket_index(__b);
        return local_iterator(_Base::end(__b), this);
      }

      const_local_iterator
      begin(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return const_local_iterator(_Base::begin(__b), this);
      }

      const_local_iterator
      end(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return const_local_iterator(_Base::end(__b), this);
      }

      const_local_iterator
      cbegin(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return const_local_iterator(_Base::cbegin(__b), this);
      }

      const_local_iterator
      cend(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return const_local_iterator(_Base::cend(__b), this);
      }

      size_type
      bucket_size(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return _Base::bucket_size(__b);
      }

      float
      max_load_factor() const noexcept
      { return _Base::max_load_factor(); }

      void
      max_load_factor(float __f)
      {
        __glibcxx_check_max_load_factor(__f);
        _Base::max_load_factor(__f);
      }

      template<typename... _Args>
        std::pair<iterator, bool>
        emplace(_Args&&... __args)
        {
          size_type __bucket_count = this->bucket_count();
          std::pair<_Base_iterator, bool> __res
            = _Base::emplace(std::forward<_Args>(__args)...);
          _M_check_rehashed(__bucket_count);
          return std::make_pair(iterator(__res.first, this), __res.second);
        }

      template<typename... _Args>
        iterator
        emplace_hint(const_iterator __hint, _Args&&... __args)
        {
          __glibcxx_check_insert(__hint);
          size_type __bucket_count = this->bucket_count();
          _Base_iterator __it = _Base::emplace_hint(__hint.base(),
                                        std::forward<_Args>(__args)...);
          _M_check_rehashed(__bucket_count);
          return iterator(__it, this);
        }

      std::pair<iterator, bool>
      insert(const value_type& __obj)
      {
        size_type __bucket_count = this->bucket_count();
        std::pair<_Base_iterator, bool> __res
          = _Base::insert(__obj);
        _M_check_rehashed(__bucket_count);
        return std::make_pair(iterator(__res.first, this), __res.second);
      }

      iterator
      insert(const_iterator __hint, const value_type& __obj)
      {
        __glibcxx_check_insert(__hint);
        size_type __bucket_count = this->bucket_count();
        _Base_iterator __it = _Base::insert(__hint.base(), __obj);
        _M_check_rehashed(__bucket_count);
        return iterator(__it, this);
      }

      std::pair<iterator, bool>
      insert(value_type&& __obj)
      {
        size_type __bucket_count = this->bucket_count();
        std::pair<_Base_iterator, bool> __res
          = _Base::insert(std::move(__obj));
        _M_check_rehashed(__bucket_count);
        return std::make_pair(iterator(__res.first, this), __res.second);
      }

      iterator
      insert(const_iterator __hint, value_type&& __obj)
      {
        __glibcxx_check_insert(__hint);
        size_type __bucket_count = this->bucket_count();
        _Base_iterator __it = _Base::insert(__hint.base(), std::move(__obj));
        _M_check_rehashed(__bucket_count);
        return iterator(__it, this);
      }

      void
      insert(std::initializer_list<value_type> __l)
      {
        size_type __bucket_count = this->bucket_count();
        _Base::insert(__l);
        _M_check_rehashed(__bucket_count);
      }

      template<typename _InputIterator>
        void
        insert(_InputIterator __first, _InputIterator __last)
        {
          __glibcxx_check_valid_range(__first, __last);
          size_type __bucket_count = this->bucket_count();
          _Base::insert(__gnu_debug::__base(__first),
                        __gnu_debug::__base(__last));
          _M_check_rehashed(__bucket_count);
        }

      iterator
      find(const key_type& __key)
      { return iterator(_Base::find(__key), this); }

      const_iterator
      find(const key_type& __key) const
      { return const_iterator(_Base::find(__key), this); }

      std::pair<iterator, iterator>
      equal_range(const key_type& __key)
      {
        std::pair<_Base_iterator, _Base_iterator> __res
          = _Base::equal_range(__key);
        return std::make_pair(iterator(__res.first, this),
                              iterator(__res.second, this));
      }

      std::pair<const_iterator, const_iterator>
      equal_range(const key_type& __key) const
      {
        std::pair<_Base_const_iterator, _Base_const_iterator>
          __res = _Base::equal_range(__key);
        return std::make_pair(const_iterator(__res.first, this),
                              const_iterator(__res.second, this));
      }

      size_type
      erase(const key_type& __key)
      {
        size_type __ret(0);
        _Base_iterator __victim(_Base::find(__key));
        if (__victim != _Base::end())
          {
            this->_M_invalidate_if(
                            [__victim](_Base_const_iterator __it)
                            { return __it == __victim; });
            this->_M_invalidate_local_if(
                            [__victim](_Base_const_local_iterator __it)
                            { return __it._M_curr() == __victim._M_cur; });
            size_type __bucket_count = this->bucket_count();
            _Base::erase(__victim);
            _M_check_rehashed(__bucket_count);
            __ret = 1;
          }
        return __ret;
      }

      iterator
      erase(const_iterator __it)
      {
        __glibcxx_check_erase(__it);
        _Base_const_iterator __victim = __it.base();
        this->_M_invalidate_if(
                        [__victim](_Base_const_iterator __it)
                        { return __it == __victim; });
        this->_M_invalidate_local_if(
                        [__victim](_Base_const_local_iterator __it)
                        { return __it._M_curr() == __victim._M_cur; });
        size_type __bucket_count = this->bucket_count();
        _Base_iterator __next = _Base::erase(__it.base());
        _M_check_rehashed(__bucket_count);
        return iterator(__next, this);
      }

      iterator
      erase(iterator __it)
      { return erase(const_iterator(__it)); }

      iterator
      erase(const_iterator __first, const_iterator __last)
      {
        __glibcxx_check_erase_range(__first, __last);
        for (_Base_const_iterator __tmp = __first.base();
             __tmp != __last.base(); ++__tmp)
          {
            _GLIBCXX_DEBUG_VERIFY(__tmp != _Base::end(),
                                  _M_message(__gnu_debug::__msg_valid_range)
                                  ._M_iterator(__first, "first")
                                  ._M_iterator(__last, "last"));
            this->_M_invalidate_if(
                            [__tmp](_Base_const_iterator __it)
                            { return __it == __tmp; });
            this->_M_invalidate_local_if(
                            [__tmp](_Base_const_local_iterator __it)
                            { return __it._M_curr() == __tmp._M_cur; });
          }
        size_type __bucket_count = this->bucket_count();
        _Base_iterator __next = _Base::erase(__first.base(),
                                             __last.base());
        _M_check_rehashed(__bucket_count);
        return iterator(__next, this);
      }

      _Base&
      _M_base() noexcept { return *this; }

      const _Base&
      _M_base() const noexcept { return *this; }

    private:
      void
      _M_check_rehashed(size_type __prev_count)
      {
        if (__prev_count != this->bucket_count())
          this->_M_invalidate_locals();
      }
    };

  template<typename _Value, typename _Hash, typename _Pred, typename _Alloc>
    inline void
    swap(unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
         unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
    { __x.swap(__y); }

  template<typename _Value, typename _Hash, typename _Pred, typename _Alloc>
    inline bool
    operator==(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
               const unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
    { return __x._M_base() == __y._M_base(); }

  template<typename _Value, typename _Hash, typename _Pred, typename _Alloc>
    inline bool
    operator!=(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
               const unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
    { return !(__x == __y); }


  /// Class std::unordered_multiset with safety/checking/debug instrumentation.
  template<typename _Value,
           typename _Hash = std::hash<_Value>,
           typename _Pred = std::equal_to<_Value>,
           typename _Alloc = std::allocator<_Value> >
    class unordered_multiset
    : public __gnu_debug::_Safe_container<
        unordered_multiset<_Value, _Hash, _Pred, _Alloc>, _Alloc,
        __gnu_debug::_Safe_unordered_container>,
      public _GLIBCXX_STD_C::unordered_multiset<_Value, _Hash, _Pred, _Alloc>
    {
      typedef _GLIBCXX_STD_C::unordered_multiset<
        _Value, _Hash, _Pred, _Alloc>                           _Base;
      typedef __gnu_debug::_Safe_container<unordered_multiset,
        _Alloc, __gnu_debug::_Safe_unordered_container>         _Safe;
      typedef typename _Base::const_iterator    _Base_const_iterator;
      typedef typename _Base::iterator          _Base_iterator;
      typedef typename _Base::const_local_iterator
                                                _Base_const_local_iterator;
      typedef typename _Base::local_iterator    _Base_local_iterator;

    public:
      typedef typename _Base::size_type                 size_type;
      typedef typename _Base::hasher                    hasher;
      typedef typename _Base::key_equal                 key_equal;
      typedef typename _Base::allocator_type            allocator_type;

      typedef typename _Base::key_type                  key_type;
      typedef typename _Base::value_type                value_type;

      typedef __gnu_debug::_Safe_iterator<
        _Base_iterator, unordered_multiset>             iterator;
      typedef __gnu_debug::_Safe_iterator<
        _Base_const_iterator, unordered_multiset>       const_iterator;
      typedef __gnu_debug::_Safe_local_iterator<
        _Base_local_iterator, unordered_multiset>       local_iterator;
      typedef __gnu_debug::_Safe_local_iterator<
        _Base_const_local_iterator, unordered_multiset> const_local_iterator;

      unordered_multiset() = default;

      explicit
      unordered_multiset(size_type __n,
                         const hasher& __hf = hasher(),
                         const key_equal& __eql = key_equal(),
                         const allocator_type& __a = allocator_type())
      : _Base(__n, __hf, __eql, __a) { }

      template<typename _InputIterator>
        unordered_multiset(_InputIterator __first, _InputIterator __last,
                           size_type __n = 0,
                           const hasher& __hf = hasher(),
                           const key_equal& __eql = key_equal(),
                           const allocator_type& __a = allocator_type())
        : _Base(__gnu_debug::__base(__gnu_debug::__check_valid_range(__first,
                                                                     __last)),
                __gnu_debug::__base(__last), __n,
                __hf, __eql, __a) { }

      unordered_multiset(const unordered_multiset&) = default;

      unordered_multiset(const _Base& __x)
      : _Base(__x) { }

      unordered_multiset(unordered_multiset&&) = default;

      explicit
      unordered_multiset(const allocator_type& __a)
      : _Base(__a) { }

      unordered_multiset(const unordered_multiset& __uset,
                         const allocator_type& __a)
      : _Base(__uset, __a) { }

      unordered_multiset(unordered_multiset&& __uset,
                         const allocator_type& __a)
      : _Safe(std::move(__uset._M_safe()), __a),
        _Base(std::move(__uset._M_base()), __a) { }

      unordered_multiset(initializer_list<value_type> __l,
                         size_type __n = 0,
                         const hasher& __hf = hasher(),
                         const key_equal& __eql = key_equal(),
                         const allocator_type& __a = allocator_type())
      : _Base(__l, __n, __hf, __eql, __a) { }

      ~unordered_multiset() = default;

      unordered_multiset&
      operator=(const unordered_multiset&) = default;

      unordered_multiset&
      operator=(unordered_multiset&&) = default;

      unordered_multiset&
      operator=(initializer_list<value_type> __l)
      {
        this->_M_base() = __l;
        this->_M_invalidate_all();
        return *this;
      }

      void
      swap(unordered_multiset& __x)
        noexcept( noexcept(declval<_Base>().swap(__x)) )
      {
        _Safe::_M_swap(__x);
        _Base::swap(__x);
      }

      void
      clear() noexcept
      {
        _Base::clear();
        this->_M_invalidate_all();
      }

      iterator
      begin() noexcept
      { return iterator(_Base::begin(), this); }

      const_iterator
      begin() const noexcept
      { return const_iterator(_Base::begin(), this); }

      iterator
      end() noexcept
      { return iterator(_Base::end(), this); }

      const_iterator
      end() const noexcept
      { return const_iterator(_Base::end(), this); }

      const_iterator
      cbegin() const noexcept
      { return const_iterator(_Base::begin(), this); }

      const_iterator
      cend() const noexcept
      { return const_iterator(_Base::end(), this); }

      // local versions
      local_iterator
      begin(size_type __b)
      {
        __glibcxx_check_bucket_index(__b);
        return local_iterator(_Base::begin(__b), this);
      }

      local_iterator
      end(size_type __b)
      {
        __glibcxx_check_bucket_index(__b);
        return local_iterator(_Base::end(__b), this);
      }

      const_local_iterator
      begin(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return const_local_iterator(_Base::begin(__b), this);
      }

      const_local_iterator
      end(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return const_local_iterator(_Base::end(__b), this);
      }

      const_local_iterator
      cbegin(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return const_local_iterator(_Base::cbegin(__b), this);
      }

      const_local_iterator
      cend(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return const_local_iterator(_Base::cend(__b), this);
      }

      size_type
      bucket_size(size_type __b) const
      {
        __glibcxx_check_bucket_index(__b);
        return _Base::bucket_size(__b);
      }

      float
      max_load_factor() const noexcept
      { return _Base::max_load_factor(); }

      void
      max_load_factor(float __f)
      {
        __glibcxx_check_max_load_factor(__f);
        _Base::max_load_factor(__f);
      }

      template<typename... _Args>
        iterator
        emplace(_Args&&... __args)
        {
          size_type __bucket_count = this->bucket_count();
          _Base_iterator __it
            = _Base::emplace(std::forward<_Args>(__args)...);
          _M_check_rehashed(__bucket_count);
          return iterator(__it, this);
        }

      template<typename... _Args>
        iterator
        emplace_hint(const_iterator __hint, _Args&&... __args)
        {
          __glibcxx_check_insert(__hint);
          size_type __bucket_count = this->bucket_count();
          _Base_iterator __it = _Base::emplace_hint(__hint.base(),
                                        std::forward<_Args>(__args)...);
          _M_check_rehashed(__bucket_count);
          return iterator(__it, this);
        }

      iterator
      insert(const value_type& __obj)
      {
        size_type __bucket_count = this->bucket_count();
        _Base_iterator __it = _Base::insert(__obj);
        _M_check_rehashed(__bucket_count);
        return iterator(__it, this);
      }

      iterator
      insert(const_iterator __hint, const value_type& __obj)
      {
        __glibcxx_check_insert(__hint);
        size_type __bucket_count = this->bucket_count();
        _Base_iterator __it = _Base::insert(__hint.base(), __obj);
        _M_check_rehashed(__bucket_count);
        return iterator(__it, this);
      }

      iterator
      insert(value_type&& __obj)
      {
        size_type __bucket_count = this->bucket_count();
        _Base_iterator __it = _Base::insert(std::move(__obj));
        _M_check_rehashed(__bucket_count);
        return iterator(__it, this);
      }

      iterator
      insert(const_iterator __hint, value_type&& __obj)
      {
        __glibcxx_check_insert(__hint);
        size_type __bucket_count = this->bucket_count();
        _Base_iterator __it = _Base::insert(__hint.base(), std::move(__obj));
        _M_check_rehashed(__bucket_count);
        return iterator(__it, this);
      }

      void
      insert(std::initializer_list<value_type> __l)
      {
        size_type __bucket_count = this->bucket_count();
        _Base::insert(__l);
        _M_check_rehashed(__bucket_count);
      }

      template<typename _InputIterator>
        void
        insert(_InputIterator __first, _InputIterator __last)
        {
          __glibcxx_check_valid_range(__first, __last);
          size_type __bucket_count = this->bucket_count();
          _Base::insert(__gnu_debug::__base(__first),
                        __gnu_debug::__base(__last));
          _M_check_rehashed(__bucket_count);
        }

      iterator
      find(const key_type& __key)
      { return iterator(_Base::find(__key), this); }

      const_iterator
      find(const key_type& __key) const
      { return const_iterator(_Base::find(__key), this); }

      std::pair<iterator, iterator>
      equal_range(const key_type& __key)
      {
        std::pair<_Base_iterator, _Base_iterator> __res
          = _Base::equal_range(__key);
        return std::make_pair(iterator(__res.first, this),
                              iterator(__res.second, this));
      }

      std::pair<const_iterator, const_iterator>
      equal_range(const key_type& __key) const
      {
        std::pair<_Base_const_iterator, _Base_const_iterator>
          __res = _Base::equal_range(__key);
        return std::make_pair(const_iterator(__res.first, this),
                              const_iterator(__res.second, this));
      }

      size_type
      erase(const key_type& __key)
      {
        size_type __ret(0);
        std::pair<_Base_iterator, _Base_iterator> __pair =
          _Base::equal_range(__key);
        for (_Base_iterator __victim = __pair.first; __victim != __pair.second;)
          {
            this->_M_invalidate_if([__victim](_Base_const_iterator __it)
                            { return __it == __victim; });
            this->_M_invalidate_local_if(
                            [__victim](_Base_const_local_iterator __it)
                            { return __it._M_curr() == __victim._M_cur; });
            _Base::erase(__victim++);
            ++__ret;
          }
        return __ret;
      }

      iterator
      erase(const_iterator __it)
      {
        __glibcxx_check_erase(__it);
        _Base_const_iterator __victim = __it.base();
        this->_M_invalidate_if([__victim](_Base_const_iterator __it)
                        { return __it == __victim; });
        this->_M_invalidate_local_if(
                        [__victim](_Base_const_local_iterator __it)
                        { return __it._M_curr() == __victim._M_cur; });
        return iterator(_Base::erase(__it.base()), this);
      }

      iterator
      erase(iterator __it)
      { return erase(const_iterator(__it)); }

      iterator
      erase(const_iterator __first, const_iterator __last)
      {
        __glibcxx_check_erase_range(__first, __last);
        for (_Base_const_iterator __tmp = __first.base();
             __tmp != __last.base(); ++__tmp)
          {
            _GLIBCXX_DEBUG_VERIFY(__tmp != _Base::end(),
                                  _M_message(__gnu_debug::__msg_valid_range)
                                  ._M_iterator(__first, "first")
                                  ._M_iterator(__last, "last"));
            this->_M_invalidate_if([__tmp](_Base_const_iterator __it)
                            { return __it == __tmp; });
            this->_M_invalidate_local_if(
                            [__tmp](_Base_const_local_iterator __it)
                            { return __it._M_curr() == __tmp._M_cur; });
          }
        return iterator(_Base::erase(__first.base(),
                                     __last.base()), this);
      }

      _Base&
      _M_base() noexcept        { return *this; }

      const _Base&
      _M_base() const noexcept  { return *this; }

    private:
      void
      _M_check_rehashed(size_type __prev_count)
      {
        if (__prev_count != this->bucket_count())
          this->_M_invalidate_locals();
      }
    };

  template<typename _Value, typename _Hash, typename _Pred, typename _Alloc>
    inline void
    swap(unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
         unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
    { __x.swap(__y); }

  template<typename _Value, typename _Hash, typename _Pred, typename _Alloc>
    inline bool
    operator==(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
               const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
    { return __x._M_base() == __y._M_base(); }

  template<typename _Value, typename _Hash, typename _Pred, typename _Alloc>
    inline bool
    operator!=(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
               const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
    { return !(__x == __y); }

} // namespace __debug
} // namespace std

#endif // C++11

#endif