multiset.h

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// Debugging multiset implementation -*- C++ -*-

// Copyright (C) 2003-2026 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/multiset.h
 *  This file is a GNU debug extension to the Standard C++ Library.
 */

#ifndef _GLIBCXX_DEBUG_MULTISET_H
#define _GLIBCXX_DEBUG_MULTISET_H 1

#include <debug/safe_sequence.h>
#include <debug/safe_container.h>
#include <debug/safe_iterator.h>
#include <bits/stl_pair.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
namespace __debug
{
  /// Class std::multiset with safety/checking/debug instrumentation.
  template<typename _Key, typename _Compare = std::less<_Key>,
           typename _Allocator = std::allocator<_Key> >
    class multiset
    : public __gnu_debug::_Safe_container<
        multiset<_Key, _Compare, _Allocator>, _Allocator,
        __gnu_debug::_Safe_node_sequence>,
      public _GLIBCXX_STD_C::multiset<_Key, _Compare, _Allocator>
    {
      typedef _GLIBCXX_STD_C::multiset<_Key, _Compare, _Allocator>      _Base;
      typedef __gnu_debug::_Safe_container<
        multiset, _Allocator, __gnu_debug::_Safe_node_sequence>         _Safe;

      typedef typename _Base::const_iterator    _Base_const_iterator;
      typedef typename _Base::iterator          _Base_iterator;
      typedef __gnu_debug::_Equal_to<_Base_const_iterator> _Equal;

      template<typename _ItT, typename _SeqT, typename _CatT>
        friend class ::__gnu_debug::_Safe_iterator;

      // Reference wrapper for base class. Disambiguates multiset(const _Base&)
      // from copy constructor by requiring a user-defined conversion.
      // See PR libstdc++/90102.
      struct _Base_ref
      {
        _Base_ref(const _Base& __r) : _M_ref(__r) { }

        const _Base& _M_ref;
      };

    public:
      // types:
      typedef _Key                                      key_type;
      typedef _Key                                      value_type;
      typedef _Compare                                  key_compare;
      typedef _Compare                                  value_compare;
      typedef _Allocator                                allocator_type;
      typedef typename _Base::reference                 reference;
      typedef typename _Base::const_reference           const_reference;

      typedef __gnu_debug::_Safe_iterator<_Base_iterator, multiset>
                                                        iterator;
      typedef __gnu_debug::_Safe_iterator<_Base_const_iterator,
                                          multiset>     const_iterator;

      typedef typename _Base::size_type                 size_type;
      typedef typename _Base::difference_type           difference_type;
      typedef typename _Base::pointer                   pointer;
      typedef typename _Base::const_pointer             const_pointer;
      typedef std::reverse_iterator<iterator>           reverse_iterator;
      typedef std::reverse_iterator<const_iterator>     const_reverse_iterator;

      // 23.3.3.1 construct/copy/destroy:

#if __cplusplus < 201103L
      multiset() : _Base() { }

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

      ~multiset() { }
#else
      multiset() = default;
      multiset(const multiset&) = default;
      multiset(multiset&&) = default;

      multiset(initializer_list<value_type> __l,
               const _Compare& __comp = _Compare(),
               const allocator_type& __a = allocator_type())
      : _Base(__l, __comp, __a) { }

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

      multiset(const multiset& __m,
               const __type_identity_t<allocator_type>& __a)
      : _Base(__m, __a) { }

      multiset(multiset&& __m, const __type_identity_t<allocator_type>& __a)
      noexcept( noexcept(_Base(std::move(__m), __a)) )
      : _Safe(std::move(__m), __a),
        _Base(std::move(__m), __a) { }

      multiset(initializer_list<value_type> __l, const allocator_type& __a)
        : _Base(__l, __a)
      { }

      template<typename _InputIterator>
        multiset(_InputIterator __first, _InputIterator __last,
                 const allocator_type& __a)
        : _Base(__gnu_debug::__base(
                  __glibcxx_check_valid_constructor_range(__first, __last)),
                __gnu_debug::__base(__last), __a) { }

#if __glibcxx_containers_ranges // C++ >= 23
      /**
       * @brief Construct a multiset from a range.
       * @since C++23
       */
      template<std::__detail::__container_compatible_range<value_type> _Rg>
        multiset(std::from_range_t __t, _Rg&& __rg,
                 const _Compare& __c,
                 const allocator_type& __a = allocator_type())
        : _Base(__t, std::forward<_Rg>(__rg), __c, __a)
        { }

      template<std::__detail::__container_compatible_range<value_type> _Rg>
        multiset(std::from_range_t __t, _Rg&& __rg,
                 const allocator_type& __a = allocator_type())
        : _Base(__t, std::forward<_Rg>(__rg), __a)
        { }
#endif

      ~multiset() = default;
#endif

      explicit multiset(const _Compare& __comp,
                        const _Allocator& __a = _Allocator())
      : _Base(__comp, __a) { }

      template<typename _InputIterator>
        multiset(_InputIterator __first, _InputIterator __last,
                 const _Compare& __comp = _Compare(),
                 const _Allocator& __a = _Allocator())
        : _Base(__gnu_debug::__base(
                  __glibcxx_check_valid_constructor_range(__first, __last)),
                __gnu_debug::__base(__last),
                __comp, __a) { }

      multiset(_Base_ref __x)
      : _Base(__x._M_ref) { }

#if __cplusplus >= 201103L
      multiset&
      operator=(const multiset&) = default;

      multiset&
      operator=(multiset&&) = default;

      multiset&
      operator=(initializer_list<value_type> __l)
      {
        _Base::operator=(__l);
        this->_M_invalidate_all();
        return *this;
      }
#endif

      using _Base::get_allocator;

      // iterators:
      iterator
      begin() _GLIBCXX_NOEXCEPT
      { return iterator(_Base::begin(), this); }

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

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

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

      reverse_iterator
      rbegin() _GLIBCXX_NOEXCEPT
      { return reverse_iterator(end()); }

      const_reverse_iterator
      rbegin() const _GLIBCXX_NOEXCEPT
      { return const_reverse_iterator(end()); }

      reverse_iterator
      rend() _GLIBCXX_NOEXCEPT
      { return reverse_iterator(begin()); }

      const_reverse_iterator
      rend() const _GLIBCXX_NOEXCEPT
      { return const_reverse_iterator(begin()); }

#if __cplusplus >= 201103L
      const_iterator
      cbegin() const noexcept
      { return const_iterator(_Base::begin(), this); }

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

      const_reverse_iterator
      crbegin() const noexcept
      { return const_reverse_iterator(end()); }

      const_reverse_iterator
      crend() const noexcept
      { return const_reverse_iterator(begin()); }
#endif

      // capacity:
      using _Base::empty;
      using _Base::size;
      using _Base::max_size;

      // modifiers:
#if __cplusplus >= 201103L
      template<typename... _Args>
        iterator
        emplace(_Args&&... __args)
        { return { _Base::emplace(std::forward<_Args>(__args)...), this }; }

      template<typename... _Args>
        iterator
        emplace_hint(const_iterator __pos, _Args&&... __args)
        {
          __glibcxx_check_insert(__pos);
          return
            {
              _Base::emplace_hint(__pos.base(), std::forward<_Args>(__args)...),
              this
            };
        }
#endif

      iterator
      insert(const value_type& __x)
      { return iterator(_Base::insert(__x), this); }

#if __cplusplus >= 201103L
      iterator
      insert(value_type&& __x)
      { return { _Base::insert(std::move(__x)), this }; }
#endif

      iterator
      insert(const_iterator __position, const value_type& __x)
      {
        __glibcxx_check_insert(__position);
        return iterator(_Base::insert(__position.base(), __x), this);
      }

#if __cplusplus >= 201103L
      iterator
      insert(const_iterator __position, value_type&& __x)
      {
        __glibcxx_check_insert(__position);
        return { _Base::insert(__position.base(), std::move(__x)), this };
      }
#endif

      template<typename _InputIterator>
        void
        insert(_InputIterator __first, _InputIterator __last)
        {
          typename __gnu_debug::_Distance_traits<_InputIterator>::__type __dist;
          __glibcxx_check_valid_range2(__first, __last, __dist);

          if (__dist.second >= __gnu_debug::__dp_sign)
            _Base::insert(__gnu_debug::__unsafe(__first),
                          __gnu_debug::__unsafe(__last));
          else
            _Base::insert(__first, __last);
        }

#if __cplusplus >= 201103L
      void
      insert(initializer_list<value_type> __l)
      { _Base::insert(__l); }
#endif

#ifdef __glibcxx_node_extract // >= C++17 && HOSTED
      using node_type = typename _Base::node_type;

      node_type
      extract(const_iterator __position)
      {
        __glibcxx_check_erase(__position);
        this->_M_invalidate_if(_Equal(__position.base()));
        return _Base::extract(__position.base());
      }

      node_type
      extract(const key_type& __key)
      {
        const auto __position = find(__key);
        if (__position != end())
          return extract(__position);
        return {};
      }

# ifdef __glibcxx_associative_heterogeneous_erasure
      template <__heterogeneous_tree_key<multiset> _Kt>
        node_type
        extract(_Kt&& __key)
        {
          const auto __position = find(__key);
          if (__position != end())
            return extract(__position);
          return {};
        }
#endif

      iterator
      insert(node_type&& __nh)
      { return { _Base::insert(std::move(__nh)), this }; }

      iterator
      insert(const_iterator __hint, node_type&& __nh)
      {
        __glibcxx_check_insert(__hint);
        return { _Base::insert(__hint.base(), std::move(__nh)), this };
      }

      using _Base::merge;
#endif // C++17

#if __cplusplus >= 201103L
      _GLIBCXX_ABI_TAG_CXX11
      iterator
      erase(const_iterator __position)
      {
        __glibcxx_check_erase(__position);
        return { erase(__position.base()), this };
      }

      _Base_iterator
      erase(_Base_const_iterator __position)
      {
        __glibcxx_check_erase2(__position);
        this->_M_invalidate_if(_Equal(__position));
        return _Base::erase(__position);
      }
#else
      void
      erase(iterator __position)
      {
        __glibcxx_check_erase(__position);
        this->_M_invalidate_if(_Equal(__position.base()));
        _Base::erase(__position.base());
      }
#endif

      size_type
      erase(const key_type& __x)
      {
        std::pair<_Base_iterator, _Base_iterator> __victims =
          _Base::equal_range(__x);
        size_type __count = 0;
        _Base_iterator __victim = __victims.first;
        while (__victim != __victims.second)
          {
            this->_M_invalidate_if(_Equal(__victim));
            _Base::erase(__victim++);
            ++__count;
          }
        return __count;
      }

# ifdef __glibcxx_associative_heterogeneous_erasure
      template <__heterogeneous_tree_key<multiset> _Kt>
        size_type
        erase(_Kt&& __x)
        {
          auto __victims = _Base::equal_range(__x);
          size_type __count = 0;
          for (auto __victim = __victims.first; __victim != __victims.second;)
            {
              this->_M_invalidate_if(_Equal(__victim));
              _Base::erase(__victim++);
              ++__count;
            }
          return __count;
        }
# endif

#if __cplusplus >= 201103L
      _GLIBCXX_ABI_TAG_CXX11
      iterator
      erase(const_iterator __first, const_iterator __last)
      {
        // _GLIBCXX_RESOLVE_LIB_DEFECTS
        // 151. can't currently clear() empty container
        __glibcxx_check_erase_range(__first, __last);
        for (_Base_const_iterator __victim = __first.base();
             __victim != __last.base(); ++__victim)
          {
            _GLIBCXX_DEBUG_VERIFY(__victim != _Base::cend(),
                                  _M_message(__gnu_debug::__msg_valid_range)
                                  ._M_iterator(__first, "first")
                                  ._M_iterator(__last, "last"));
            this->_M_invalidate_if(_Equal(__victim));
          }

        return { _Base::erase(__first.base(), __last.base()), this };
      }
#else
      void
      erase(iterator __first, iterator __last)
      {
        // _GLIBCXX_RESOLVE_LIB_DEFECTS
        // 151. can't currently clear() empty container
        __glibcxx_check_erase_range(__first, __last);
        for (_Base_iterator __victim = __first.base();
             __victim != __last.base(); ++__victim)
          {
            _GLIBCXX_DEBUG_VERIFY(__victim != _Base::end(),
                                  _M_message(__gnu_debug::__msg_valid_range)
                                  ._M_iterator(__first, "first")
                                  ._M_iterator(__last, "last"));
            this->_M_invalidate_if(_Equal(__victim));
          }
        _Base::erase(__first.base(), __last.base());
      }
#endif

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

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

      // observers:
      using _Base::key_comp;
      using _Base::value_comp;

      // multiset operations:
      iterator
      find(const key_type& __x)
      { return iterator(_Base::find(__x), this); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 214. set::find() missing const overload
      const_iterator
      find(const key_type& __x) const
      { return const_iterator(_Base::find(__x), this); }

#ifdef __glibcxx_generic_associative_lookup // C++ >= 14
      template<typename _Kt,
               typename _Req =
                 typename __has_is_transparent<_Compare, _Kt>::type>
        iterator
        find(const _Kt& __x)
        { return { _Base::find(__x), this }; }

      template<typename _Kt,
               typename _Req =
                 typename __has_is_transparent<_Compare, _Kt>::type>
        const_iterator
        find(const _Kt& __x) const
        { return { _Base::find(__x), this }; }
#endif

      using _Base::count;

      iterator
      lower_bound(const key_type& __x)
      { return iterator(_Base::lower_bound(__x), this); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 214. set::find() missing const overload
      const_iterator
      lower_bound(const key_type& __x) const
      { return const_iterator(_Base::lower_bound(__x), this); }

#ifdef __glibcxx_generic_associative_lookup // C++ >= 14
      template<typename _Kt,
               typename _Req =
                 typename __has_is_transparent<_Compare, _Kt>::type>
        iterator
        lower_bound(const _Kt& __x)
        { return { _Base::lower_bound(__x), this }; }

      template<typename _Kt,
               typename _Req =
                 typename __has_is_transparent<_Compare, _Kt>::type>
        const_iterator
        lower_bound(const _Kt& __x) const
        { return { _Base::lower_bound(__x), this }; }
#endif

      iterator
      upper_bound(const key_type& __x)
      { return iterator(_Base::upper_bound(__x), this); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 214. set::find() missing const overload
      const_iterator
      upper_bound(const key_type& __x) const
      { return const_iterator(_Base::upper_bound(__x), this); }

#ifdef __glibcxx_generic_associative_lookup // C++ >= 14
      template<typename _Kt,
               typename _Req =
                 typename __has_is_transparent<_Compare, _Kt>::type>
        iterator
        upper_bound(const _Kt& __x)
        { return { _Base::upper_bound(__x), this }; }

      template<typename _Kt,
               typename _Req =
                 typename __has_is_transparent<_Compare, _Kt>::type>
        const_iterator
        upper_bound(const _Kt& __x) const
        { return { _Base::upper_bound(__x), this }; }
#endif

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

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 214. set::find() missing const overload
      std::pair<const_iterator,const_iterator>
      equal_range(const key_type& __x) const
      {
        std::pair<_Base_const_iterator, _Base_const_iterator> __res =
          _Base::equal_range(__x);
        return std::make_pair(const_iterator(__res.first, this),
                              const_iterator(__res.second, this));
      }

#ifdef __glibcxx_generic_associative_lookup // C++ >= 14
      template<typename _Kt,
               typename _Req =
                 typename __has_is_transparent<_Compare, _Kt>::type>
        std::pair<iterator, iterator>
        equal_range(const _Kt& __x)
        {
          auto __res = _Base::equal_range(__x);
          return { { __res.first, this }, { __res.second, this } };
        }

      template<typename _Kt,
               typename _Req =
                 typename __has_is_transparent<_Compare, _Kt>::type>
        std::pair<const_iterator, const_iterator>
        equal_range(const _Kt& __x) const
        {
          auto __res = _Base::equal_range(__x);
          return { { __res.first, this }, { __res.second, this } };
        }
#endif

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

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

#if __cpp_deduction_guides >= 201606

  template<typename _InputIterator,
           typename _Compare =
             less<typename iterator_traits<_InputIterator>::value_type>,
           typename _Allocator =
             allocator<typename iterator_traits<_InputIterator>::value_type>,
           typename = _RequireInputIter<_InputIterator>,
           typename = _RequireNotAllocator<_Compare>,
           typename = _RequireAllocator<_Allocator>>
    multiset(_InputIterator, _InputIterator,
             _Compare = _Compare(), _Allocator = _Allocator())
    -> multiset<typename iterator_traits<_InputIterator>::value_type,
                _Compare, _Allocator>;

  template<typename _Key,
           typename _Compare = less<_Key>,
           typename _Allocator = allocator<_Key>,
           typename = _RequireNotAllocator<_Compare>,
           typename = _RequireAllocator<_Allocator>>
    multiset(initializer_list<_Key>,
             _Compare = _Compare(), _Allocator = _Allocator())
    -> multiset<_Key, _Compare, _Allocator>;

  template<typename _InputIterator, typename _Allocator,
           typename = _RequireInputIter<_InputIterator>,
           typename = _RequireAllocator<_Allocator>>
    multiset(_InputIterator, _InputIterator, _Allocator)
    -> multiset<typename iterator_traits<_InputIterator>::value_type,
                less<typename iterator_traits<_InputIterator>::value_type>,
                _Allocator>;

  template<typename _Key, typename _Allocator,
           typename = _RequireAllocator<_Allocator>>
    multiset(initializer_list<_Key>, _Allocator)
    -> multiset<_Key, less<_Key>, _Allocator>;

#if __glibcxx_containers_ranges // C++ >= 23
  template<ranges::input_range _Rg,
           __not_allocator_like _Compare = less<ranges::range_value_t<_Rg>>,
           __allocator_like _Alloc = std::allocator<ranges::range_value_t<_Rg>>>
    multiset(from_range_t, _Rg&&, _Compare = _Compare(), _Alloc = _Alloc())
      -> multiset<ranges::range_value_t<_Rg>, _Compare, _Alloc>;

  template<ranges::input_range _Rg, __allocator_like _Alloc>
    multiset(from_range_t, _Rg&&, _Alloc)
      -> multiset<ranges::range_value_t<_Rg>, less<ranges::range_value_t<_Rg>>, _Alloc>;
#endif
#endif // deduction guides

  template<typename _Key, typename _Compare, typename _Allocator>
    inline bool
    operator==(const multiset<_Key, _Compare, _Allocator>& __lhs,
               const multiset<_Key, _Compare, _Allocator>& __rhs)
    { return __lhs._M_base() == __rhs._M_base(); }

#if __cpp_lib_three_way_comparison
  template<typename _Key, typename _Compare, typename _Alloc>
    inline __detail::__synth3way_t<_Key>
    operator<=>(const multiset<_Key, _Compare, _Alloc>& __lhs,
                const multiset<_Key, _Compare, _Alloc>& __rhs)
    { return __lhs._M_base() <=> __rhs._M_base(); }
#else
  template<typename _Key, typename _Compare, typename _Allocator>
    inline bool
    operator!=(const multiset<_Key, _Compare, _Allocator>& __lhs,
               const multiset<_Key, _Compare, _Allocator>& __rhs)
    { return __lhs._M_base() != __rhs._M_base(); }

  template<typename _Key, typename _Compare, typename _Allocator>
    inline bool
    operator<(const multiset<_Key, _Compare, _Allocator>& __lhs,
              const multiset<_Key, _Compare, _Allocator>& __rhs)
    { return __lhs._M_base() < __rhs._M_base(); }

  template<typename _Key, typename _Compare, typename _Allocator>
    inline bool
    operator<=(const multiset<_Key, _Compare, _Allocator>& __lhs,
               const multiset<_Key, _Compare, _Allocator>& __rhs)
    { return __lhs._M_base() <= __rhs._M_base(); }

  template<typename _Key, typename _Compare, typename _Allocator>
    inline bool
    operator>=(const multiset<_Key, _Compare, _Allocator>& __lhs,
               const multiset<_Key, _Compare, _Allocator>& __rhs)
    { return __lhs._M_base() >= __rhs._M_base(); }

  template<typename _Key, typename _Compare, typename _Allocator>
    inline bool
    operator>(const multiset<_Key, _Compare, _Allocator>& __lhs,
              const multiset<_Key, _Compare, _Allocator>& __rhs)
    { return __lhs._M_base() > __rhs._M_base(); }
#endif // three-way comparison

  template<typename _Key, typename _Compare, typename _Allocator>
    void
    swap(multiset<_Key, _Compare, _Allocator>& __x,
         multiset<_Key, _Compare, _Allocator>& __y)
    _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
    { return __x.swap(__y); }

} // namespace __debug
} // namespace std

#endif