list.tcc

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// List implementation (out of line) -*- C++ -*-
 
// Copyright (C) 2001-2026 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/>.
 
/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996,1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */
 
/** @file bits/list.tcc
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{list}
 */
 
#ifndef _LIST_TCC
#define _LIST_TCC 1
 
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
  template<typename _Tp, typename _Alloc>
    void
    _List_base<_Tp, _Alloc>::
    _M_clear() _GLIBCXX_NOEXCEPT
    {
      typedef typename _Node_traits::_Node  _Node;
      typedef typename _Node_traits::_Node_base  _Node_base;
      typename _Node_base::_Base_ptr __cur = _M_impl._M_node._M_next;
      while (__cur != _M_impl._M_node._M_base())
      {
        _Node& __tmp = static_cast<_Node&>(*__cur);
        __cur = __tmp._M_next;
        this->_M_destroy_node(__tmp._M_node_ptr());
      }
    }
 
#if __cplusplus >= 201103L
  template<typename _Tp, typename _Alloc>
    template<typename... _Args>
      typename list<_Tp, _Alloc>::iterator
      list<_Tp, _Alloc>::
      emplace(const_iterator __position, _Args&&... __args)
      {
      _Node_ptr __tmp = _M_create_node(std::forward<_Args>(__args)...);
      __tmp->_M_hook(__position._M_const_cast()._M_node);
      this->_M_inc_size(1);
      return iterator(__tmp->_M_base());
      }
#endif
 
  template<typename _Tp, typename _Alloc>
    typename list<_Tp, _Alloc>::iterator
    list<_Tp, _Alloc>::
#if __cplusplus >= 201103L
    insert(const_iterator __position, const value_type& __x)
#else
    insert(iterator __position, const value_type& __x)
#endif
    {
      _Node_ptr __tmp = _M_create_node(__x);
      __tmp->_M_hook(__position._M_const_cast()._M_node);
      this->_M_inc_size(1);
      return iterator(__tmp->_M_base());
    }
 
#if __cplusplus >= 201103L
  template<typename _Tp, typename _Alloc>
    typename list<_Tp, _Alloc>::iterator
    list<_Tp, _Alloc>::
    insert(const_iterator __position, size_type __n, const value_type& __x)
    {
      if (__n)
      {
        list __tmp(__n, __x, get_allocator());
        iterator __it = __tmp.begin();
        splice(__position, __tmp);
        return __it;
      }
      return __position._M_const_cast();
    }
 
  template<typename _Tp, typename _Alloc>
    template<typename _InputIterator, typename>
      typename list<_Tp, _Alloc>::iterator
      list<_Tp, _Alloc>::
      insert(const_iterator __position, _InputIterator __first,
           _InputIterator __last)
      {
      list __tmp(__first, __last, get_allocator());
      if (!__tmp.empty())
        {
          iterator __it = __tmp.begin();
          splice(__position, __tmp);
          return __it;
        }
      return __position._M_const_cast();
      }
#endif
 
  template<typename _Tp, typename _Alloc>
    typename list<_Tp, _Alloc>::iterator
    list<_Tp, _Alloc>::
#if __cplusplus >= 201103L
    erase(const_iterator __position) noexcept
#else
    erase(iterator __position)
#endif
    {
      iterator __ret = iterator(__position._M_node->_M_next);
      _M_erase(__position._M_const_cast());
      return __ret;
    }
 
  // Return a const_iterator indicating the position to start inserting or
  // erasing elements (depending whether the list is growing or shrinking),
  // and set __new_size to the number of new elements that must be appended.
  // Equivalent to the following, but performed optimally:
  // if (__new_size < size()) {
  //   __new_size = 0;
  //   return std::next(begin(), __new_size);
  // } else {
  //   __newsize -= size();
  //   return end();
  // }
  template<typename _Tp, typename _Alloc>
    typename list<_Tp, _Alloc>::const_iterator
    list<_Tp, _Alloc>::
    _M_resize_pos(size_type& __new_size) const
    {
      const_iterator __i;
#if _GLIBCXX_USE_CXX11_ABI
      const size_type __len = size();
      if (__new_size < __len)
      {
        if (__new_size <= __len / 2)
          {
            __i = begin();
            std::advance(__i, __new_size);
          }
        else
          {
            __i = end();
            ptrdiff_t __num_erase = __len - __new_size;
            std::advance(__i, -__num_erase);
          }
        __new_size = 0;
        return __i;
      }
      else
      __i = end();
#else
      size_type __len = 0;
      for (__i = begin(); __i != end() && __len < __new_size; ++__i, ++__len)
        ;
#endif
      __new_size -= __len;
      return __i;
    }
 
#if __cplusplus >= 201103L
  template<typename _Tp, typename _Alloc>
    void
    list<_Tp, _Alloc>::
    _M_default_append(size_type __n)
    {
      size_type __i = 0;
      __try
      {
        for (; __i < __n; ++__i)
          emplace_back();
      }
      __catch(...)
      {
        for (; __i; --__i)
          pop_back();
        __throw_exception_again;
      }
    }
 
  template<typename _Tp, typename _Alloc>
    void
    list<_Tp, _Alloc>::
    resize(size_type __new_size)
    {
      const_iterator __i = _M_resize_pos(__new_size);
      if (__new_size)
      _M_default_append(__new_size);
      else
        erase(__i, end());
    }
 
  template<typename _Tp, typename _Alloc>
    void
    list<_Tp, _Alloc>::
    resize(size_type __new_size, const value_type& __x)
    {
      const_iterator __i = _M_resize_pos(__new_size);
      if (__new_size)
        insert(end(), __new_size, __x);
      else
        erase(__i, end());
    }
#else
  template<typename _Tp, typename _Alloc>
    void
    list<_Tp, _Alloc>::
    resize(size_type __new_size, value_type __x)
    {
      const_iterator __i = _M_resize_pos(__new_size);
      if (__new_size)
        insert(end(), __new_size, __x);
      else
        erase(__i._M_const_cast(), end());
    }
#endif
 
  template<typename _Tp, typename _Alloc>
    list<_Tp, _Alloc>&
    list<_Tp, _Alloc>::
    operator=(const list& __x)
    {
      if (this != std::__addressof(__x))
      {
#if __cplusplus >= 201103L
        if (_Node_alloc_traits::_S_propagate_on_copy_assign())
          {
              auto& __this_alloc = this->_M_get_Node_allocator();
              auto& __that_alloc = __x._M_get_Node_allocator();
              if (!_Node_alloc_traits::_S_always_equal()
                && __this_alloc != __that_alloc)
              {
              // replacement allocator cannot free existing storage
              clear();
            }
            std::__alloc_on_copy(__this_alloc, __that_alloc);
            }
#endif
        _M_assign_dispatch(__x.begin(), __x.end(), __false_type());
      }
      return *this;
    }
 
  template<typename _Tp, typename _Alloc>
    void
    list<_Tp, _Alloc>::
    _M_fill_assign(size_type __n, const value_type& __val)
    {
      iterator __i = begin();
      for (; __i != end() && __n > 0; ++__i, --__n)
        *__i = __val;
      if (__n > 0)
        insert(end(), __n, __val);
      else
        erase(__i, end());
    }
 
  template<typename _Tp, typename _Alloc>
    template <typename _InputIterator>
      void
      list<_Tp, _Alloc>::
      _M_assign_dispatch(_InputIterator __first2, _InputIterator __last2,
                   __false_type)
      {
        iterator __first1 = begin();
        iterator __last1 = end();
        for (; __first1 != __last1 && __first2 != __last2;
           ++__first1, (void)++__first2)
          *__first1 = *__first2;
        if (__first2 == __last2)
          erase(__first1, __last1);
        else
          insert(__last1, __first2, __last2);
      }
 
#if __cplusplus > 201703L
# define _GLIBCXX20_ONLY(__expr) __expr
#else
# define _GLIBCXX20_ONLY(__expr)
#endif
 
  template<typename _Tp, typename _Alloc>
    typename list<_Tp, _Alloc>::__remove_return_type
    list<_Tp, _Alloc>::
    remove(const value_type& __value)
    {
#if !_GLIBCXX_USE_CXX11_ABI
      size_type __removed __attribute__((__unused__)) = 0;
#endif
      list __to_destroy(get_allocator());
      iterator __first = begin();
      iterator __last = end();
      while (__first != __last)
      {
        iterator __next = __first;
        ++__next;
        if (*__first == __value)
          {
            // _GLIBCXX_RESOLVE_LIB_DEFECTS
            // 526. Is it undefined if a function in the standard changes
            // in parameters?
            __to_destroy.splice(__to_destroy.begin(), *this, __first);
#if !_GLIBCXX_USE_CXX11_ABI
            _GLIBCXX20_ONLY( __removed++ );
#endif
          }
 
        __first = __next;
      }
 
#if !_GLIBCXX_USE_CXX11_ABI
      return _GLIBCXX20_ONLY( __removed );
#else
      return _GLIBCXX20_ONLY( __to_destroy.size() );
#endif
    }
 
  template<typename _Tp, typename _Alloc>
    typename list<_Tp, _Alloc>::__remove_return_type
    list<_Tp, _Alloc>::
    unique()
    {
      iterator __first = begin();
      iterator __last = end();
      if (__first == __last)
      return _GLIBCXX20_ONLY( 0 );
#if !_GLIBCXX_USE_CXX11_ABI
      size_type __removed __attribute__((__unused__)) = 0;
#endif
      list __to_destroy(get_allocator());
      iterator __next = __first;
      while (++__next != __last)
      {
        if (*__first == *__next)
          {
            __to_destroy.splice(__to_destroy.begin(), *this, __next);
#if !_GLIBCXX_USE_CXX11_ABI
            _GLIBCXX20_ONLY( __removed++ );
#endif
          }
        else
          __first = __next;
        __next = __first;
      }
 
#if !_GLIBCXX_USE_CXX11_ABI
      return _GLIBCXX20_ONLY( __removed );
#else
      return _GLIBCXX20_ONLY( __to_destroy.size() );
#endif
    }
 
  template<typename _Tp, typename _Alloc>
    void
    list<_Tp, _Alloc>::
#if __cplusplus >= 201103L
    merge(list&& __x)
#else
    merge(list& __x)
#endif
    {
      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 300. list::merge() specification incomplete
      if (this != std::__addressof(__x))
      {
        _M_check_equal_allocators(__x);
 
        iterator __first1 = begin();
        iterator __last1 = end();
        iterator __first2 = __x.begin();
        iterator __last2 = __x.end();
 
        const _Finalize_merge __fin(*this, __x, __first2);
 
        while (__first1 != __last1 && __first2 != __last2)
          if (*__first2 < *__first1)
            {
            iterator __next = __first2;
            _M_transfer(__first1, __first2, ++__next);
            __first2 = __next;
            }
          else
            ++__first1;
        if (__first2 != __last2)
          {
            _M_transfer(__last1, __first2, __last2);
            __first2 = __last2;
          }
      }
    }
 
  template<typename _Tp, typename _Alloc>
    template <typename _StrictWeakOrdering>
      void
      list<_Tp, _Alloc>::
#if __cplusplus >= 201103L
      merge(list&& __x, _StrictWeakOrdering __comp)
#else
      merge(list& __x, _StrictWeakOrdering __comp)
#endif
      {
      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 300. list::merge() specification incomplete
      if (this != std::__addressof(__x))
        {
          _M_check_equal_allocators(__x);
 
          iterator __first1 = begin();
          iterator __last1 = end();
          iterator __first2 = __x.begin();
          iterator __last2 = __x.end();
 
          const _Finalize_merge __fin(*this, __x, __first2);
 
          while (__first1 != __last1 && __first2 != __last2)
            if (__comp(*__first2, *__first1))
            {
              iterator __next = __first2;
              _M_transfer(__first1, __first2, ++__next);
              __first2 = __next;
            }
            else
            ++__first1;
          if (__first2 != __last2)
            {
            _M_transfer(__last1, __first2, __last2);
            __first2 = __last2;
            }
        }
      }
 
  template<typename _Tp, typename _Alloc>
    void
    list<_Tp, _Alloc>::
    sort()
    {
      // Do nothing if the list has length 0 or 1.
      if (empty() || ++begin() == end())
      return;
 
      {
      typedef __list::_Scratch_list<typename _Node_traits::_Node_base>
        _Scratch_list;
 
      // The algorithm used here is largely unchanged from the SGI STL
      // and is described in The C++ Standard Template Library by Plauger,
      // Stepanov, Lee, Musser.
      // Each element of *this is spliced out and merged into one of the
      // sorted lists in __tmp, then all the lists in __tmp are merged
      // together and then swapped back into *this.
      // Because all nodes end up back in *this we do not need to update
      // this->size() while nodes are temporarily moved out.
      _Scratch_list __carry;
      _Scratch_list __tmp[64];
      _Scratch_list* __fill = __tmp;
      _Scratch_list* __counter;
 
      typename _Scratch_list::template _Ptr_cmp<iterator, void> __ptr_comp;
 
      __try
        {
          do
            {
            __carry._M_take_one(begin()._M_node);
 
            for(__counter = __tmp;
                __counter != __fill && !__counter->empty();
                ++__counter)
              {
 
                __counter->merge(__carry, __ptr_comp);
                __carry.swap(*__counter);
              }
            __carry.swap(*__counter);
            if (__counter == __fill)
              ++__fill;
            }
          while ( !empty() );
 
          for (__counter = __tmp + 1; __counter != __fill; ++__counter)
            __counter->merge(__counter[-1], __ptr_comp);
          __fill[-1].swap(this->_M_impl._M_node);
        }
      __catch(...)
        {
          // Move all nodes back into *this.
          __carry._M_put_all(end()._M_node);
          for (int __i = 0; __i < sizeof(__tmp)/sizeof(__tmp[0]); ++__i)
            __tmp[__i]._M_put_all(end()._M_node);
          __throw_exception_again;
        }
      }
    }
 
  template<typename _Tp, typename _Alloc>
    template <typename _Predicate>
      typename list<_Tp, _Alloc>::__remove_return_type
      list<_Tp, _Alloc>::
      remove_if(_Predicate __pred)
      {
#if !_GLIBCXX_USE_CXX11_ABI
      size_type __removed __attribute__((__unused__)) = 0;
#endif
      list __to_destroy(get_allocator());
      iterator __first = begin();
      iterator __last = end();
      while (__first != __last)
        {
          iterator __next = __first;
          ++__next;
          if (__pred(*__first))
            {
            __to_destroy.splice(__to_destroy.begin(), *this, __first);
#if !_GLIBCXX_USE_CXX11_ABI
            _GLIBCXX20_ONLY( __removed++ );
#endif
            }
          __first = __next;
        }
 
#if !_GLIBCXX_USE_CXX11_ABI
      return _GLIBCXX20_ONLY( __removed );
#else
      return _GLIBCXX20_ONLY( __to_destroy.size() );
#endif
      }
 
  template<typename _Tp, typename _Alloc>
    template <typename _BinaryPredicate>
      typename list<_Tp, _Alloc>::__remove_return_type
      list<_Tp, _Alloc>::
      unique(_BinaryPredicate __binary_pred)
      {
        iterator __first = begin();
        iterator __last = end();
        if (__first == __last)
        return _GLIBCXX20_ONLY(0);
#if !_GLIBCXX_USE_CXX11_ABI
        size_type __removed __attribute__((__unused__)) = 0;
#endif
      list __to_destroy(get_allocator());
        iterator __next = __first;
        while (++__next != __last)
        {
          if (__binary_pred(*__first, *__next))
            {
            __to_destroy.splice(__to_destroy.begin(), *this, __next);
#if !_GLIBCXX_USE_CXX11_ABI
            _GLIBCXX20_ONLY( __removed++ );
#endif
            }
          else
            __first = __next;
          __next = __first;
        }
 
#if !_GLIBCXX_USE_CXX11_ABI
      return _GLIBCXX20_ONLY( __removed );
#else
      return _GLIBCXX20_ONLY( __to_destroy.size() );
#endif
      }
 
#undef _GLIBCXX20_ONLY
 
  template<typename _Tp, typename _Alloc>
    template <typename _StrictWeakOrdering>
      void
      list<_Tp, _Alloc>::
      sort(_StrictWeakOrdering __comp)
      {
      // Do nothing if the list has length 0 or 1.
      if (empty() || ++begin() == end())
        return;
 
      {
        typedef __list::_Scratch_list<typename _Node_traits::_Node_base>
          _Scratch_list;
 
        _Scratch_list __carry;
        _Scratch_list __tmp[64];
        _Scratch_list* __fill = __tmp;
        _Scratch_list* __counter;
 
        typename _Scratch_list::
          template _Ptr_cmp<iterator, _StrictWeakOrdering> __ptr_comp
          = { __comp };
 
        __try
          {
            do
            {
              __carry._M_take_one(begin()._M_node);
 
              for(__counter = __tmp;
                  __counter != __fill && !__counter->empty();
                  ++__counter)
                {
 
                  __counter->merge(__carry, __ptr_comp);
                  __carry.swap(*__counter);
                }
              __carry.swap(*__counter);
              if (__counter == __fill)
                ++__fill;
            }
            while ( !empty() );
 
            for (__counter = __tmp + 1; __counter != __fill; ++__counter)
            __counter->merge(__counter[-1], __ptr_comp);
            __fill[-1].swap(this->_M_impl._M_node);
          }
        __catch(...)
          {
            // Move all nodes back into *this.
            __carry._M_put_all(end()._M_node);
            for (size_t __i = 0; __i < sizeof(__tmp)/sizeof(__tmp[0]); ++__i)
            __tmp[__i]._M_put_all(end()._M_node);
            __throw_exception_again;
          }
      }
      }
 
_GLIBCXX_END_NAMESPACE_CONTAINER
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
 
#endif /* _LIST_TCC */