stl_list.h

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// List implementation -*- C++ -*-

// Copyright (C) 2001, 2002, 2003, 2004, 2005 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 2, 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.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/*
 *
 * 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.
 */

#ifndef _LIST_H
#define _LIST_H 1

#include <bits/concept_check.h>

namespace _GLIBCXX_STD
{
  // Supporting structures are split into common and templated types; the
  // latter publicly inherits from the former in an effort to reduce code
  // duplication.  This results in some "needless" static_cast'ing later on,
  // but it's all safe downcasting.

  struct _List_node_base
  {
    _List_node_base* _M_next;   
    _List_node_base* _M_prev;   

    static void
    swap(_List_node_base& __x, _List_node_base& __y);

    void
    transfer(_List_node_base * const __first,
         _List_node_base * const __last);

    void
    reverse();

    void
    hook(_List_node_base * const __position);

    void
    unhook();
  };

  template<typename _Tp>
    struct _List_node : public _List_node_base
    {
      _Tp _M_data;                
    };

  template<typename _Tp>
    struct _List_iterator
    {
      typedef _List_iterator<_Tp>                _Self;
      typedef _List_node<_Tp>                    _Node;

      typedef ptrdiff_t                          difference_type;
      typedef std::bidirectional_iterator_tag    iterator_category;
      typedef _Tp                                value_type;
      typedef _Tp*                               pointer;
      typedef _Tp&                               reference;

      _List_iterator()
      : _M_node() { }

      explicit
      _List_iterator(_List_node_base* __x)
      : _M_node(__x) { }

      // Must downcast from List_node_base to _List_node to get to _M_data.
      reference
      operator*() const
      { return static_cast<_Node*>(_M_node)->_M_data; }

      pointer
      operator->() const
      { return &static_cast<_Node*>(_M_node)->_M_data; }

      _Self&
      operator++()
      {
    _M_node = _M_node->_M_next;
    return *this;
      }

      _Self
      operator++(int)
      {
    _Self __tmp = *this;
    _M_node = _M_node->_M_next;
    return __tmp;
      }

      _Self&
      operator--()
      {
    _M_node = _M_node->_M_prev;
    return *this;
      }

      _Self
      operator--(int)
      {
    _Self __tmp = *this;
    _M_node = _M_node->_M_prev;
    return __tmp;
      }

      bool
      operator==(const _Self& __x) const
      { return _M_node == __x._M_node; }

      bool
      operator!=(const _Self& __x) const
      { return _M_node != __x._M_node; }

      // The only member points to the %list element.
      _List_node_base* _M_node;
    };

  template<typename _Tp>
    struct _List_const_iterator
    {
      typedef _List_const_iterator<_Tp>          _Self;
      typedef const _List_node<_Tp>              _Node;
      typedef _List_iterator<_Tp>                iterator;

      typedef ptrdiff_t                          difference_type;
      typedef std::bidirectional_iterator_tag    iterator_category;
      typedef _Tp                                value_type;
      typedef const _Tp*                         pointer;
      typedef const _Tp&                         reference;

      _List_const_iterator()
      : _M_node() { }

      explicit
      _List_const_iterator(const _List_node_base* __x)
      : _M_node(__x) { }

      _List_const_iterator(const iterator& __x)
      : _M_node(__x._M_node) { }

      // Must downcast from List_node_base to _List_node to get to
      // _M_data.
      reference
      operator*() const
      { return static_cast<_Node*>(_M_node)->_M_data; }

      pointer
      operator->() const
      { return &static_cast<_Node*>(_M_node)->_M_data; }

      _Self&
      operator++()
      {
    _M_node = _M_node->_M_next;
    return *this;
      }

      _Self
      operator++(int)
      {
    _Self __tmp = *this;
    _M_node = _M_node->_M_next;
    return __tmp;
      }

      _Self&
      operator--()
      {
    _M_node = _M_node->_M_prev;
    return *this;
      }

      _Self
      operator--(int)
      {
    _Self __tmp = *this;
    _M_node = _M_node->_M_prev;
    return __tmp;
      }

      bool
      operator==(const _Self& __x) const
      { return _M_node == __x._M_node; }

      bool
      operator!=(const _Self& __x) const
      { return _M_node != __x._M_node; }

      // The only member points to the %list element.
      const _List_node_base* _M_node;
    };

  template<typename _Val>
    inline bool
    operator==(const _List_iterator<_Val>& __x,
           const _List_const_iterator<_Val>& __y)
    { return __x._M_node == __y._M_node; }

  template<typename _Val>
    inline bool
    operator!=(const _List_iterator<_Val>& __x,
               const _List_const_iterator<_Val>& __y)
    { return __x._M_node != __y._M_node; }


  template<typename _Tp, typename _Alloc>
    class _List_base
    {
    protected:
      // NOTA BENE
      // The stored instance is not actually of "allocator_type"'s
      // type.  Instead we rebind the type to
      // Allocator<List_node<Tp>>, which according to [20.1.5]/4
      // should probably be the same.  List_node<Tp> is not the same
      // size as Tp (it's two pointers larger), and specializations on
      // Tp may go unused because List_node<Tp> is being bound
      // instead.
      //
      // We put this to the test in the constructors and in
      // get_allocator, where we use conversions between
      // allocator_type and _Node_alloc_type. The conversion is
      // required by table 32 in [20.1.5].
      typedef typename _Alloc::template rebind<_List_node<_Tp> >::other
        _Node_alloc_type;

      typedef typename _Alloc::template rebind<_Tp>::other _Tp_alloc_type;

      struct _List_impl 
      : public _Node_alloc_type
      {
    _List_node_base _M_node;

    _List_impl(const _Node_alloc_type& __a)
    : _Node_alloc_type(__a), _M_node()
    { }
      };

      _List_impl _M_impl;

      _List_node<_Tp>*
      _M_get_node()
      { return _M_impl._Node_alloc_type::allocate(1); }
      
      void
      _M_put_node(_List_node<_Tp>* __p)
      { _M_impl._Node_alloc_type::deallocate(__p, 1); }
      
  public:
      typedef _Alloc allocator_type;

      _Tp_alloc_type
      _M_get_Tp_allocator() const
      { return *static_cast<const _Node_alloc_type*>(&this->_M_impl); }

      allocator_type
      get_allocator() const
      { return _M_get_Tp_allocator(); }

      _List_base(const allocator_type& __a)
      : _M_impl(__a)
      { _M_init(); }

      // This is what actually destroys the list.
      ~_List_base()
      { _M_clear(); }

      void
      _M_clear();

      void
      _M_init()
      {
        this->_M_impl._M_node._M_next = &this->_M_impl._M_node;
        this->_M_impl._M_node._M_prev = &this->_M_impl._M_node;
      }
    };

  template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
    class list : protected _List_base<_Tp, _Alloc>
    {
      // concept requirements
      typedef typename _Alloc::value_type                _Alloc_value_type;
      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
      __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)

      typedef _List_base<_Tp, _Alloc>                    _Base;
      typedef typename _Base::_Tp_alloc_type         _Tp_alloc_type;

    public:
      typedef _Tp                                        value_type;
      typedef typename _Tp_alloc_type::pointer           pointer;
      typedef typename _Tp_alloc_type::const_pointer     const_pointer;
      typedef typename _Tp_alloc_type::reference         reference;
      typedef typename _Tp_alloc_type::const_reference   const_reference;
      typedef _List_iterator<_Tp>                        iterator;
      typedef _List_const_iterator<_Tp>                  const_iterator;
      typedef std::reverse_iterator<const_iterator>      const_reverse_iterator;
      typedef std::reverse_iterator<iterator>            reverse_iterator;
      typedef size_t                                     size_type;
      typedef ptrdiff_t                                  difference_type;
      typedef _Alloc                                     allocator_type;

    protected:
      // Note that pointers-to-_Node's can be ctor-converted to
      // iterator types.
      typedef _List_node<_Tp>                _Node;

      using _Base::_M_impl;
      using _Base::_M_put_node;
      using _Base::_M_get_node;
      using _Base::_M_get_Tp_allocator;

      _Node*
      _M_create_node(const value_type& __x)
      {
    _Node* __p = this->_M_get_node();
    try
      {
        _M_get_Tp_allocator().construct(&__p->_M_data, __x);
      }
    catch(...)
      {
        _M_put_node(__p);
        __throw_exception_again;
      }
    return __p;
      }

    public:
      // [23.2.2.1] construct/copy/destroy
      // (assign() and get_allocator() are also listed in this section)
      explicit
      list(const allocator_type& __a = allocator_type())
      : _Base(__a) { }

      explicit
      list(size_type __n, const value_type& __value = value_type(),
       const allocator_type& __a = allocator_type())
      : _Base(__a)
      { this->insert(begin(), __n, __value); }

      list(const list& __x)
      : _Base(__x.get_allocator())
      { this->insert(begin(), __x.begin(), __x.end()); }

      template<typename _InputIterator>
        list(_InputIterator __first, _InputIterator __last,
         const allocator_type& __a = allocator_type())
        : _Base(__a)
        { this->insert(begin(), __first, __last); }

      list&
      operator=(const list& __x);

      void
      assign(size_type __n, const value_type& __val)
      { _M_fill_assign(__n, __val); }

      template<typename _InputIterator>
        void
        assign(_InputIterator __first, _InputIterator __last)
        {
      // Check whether it's an integral type.  If so, it's not an iterator.
      typedef typename std::__is_integer<_InputIterator>::__type _Integral;
      _M_assign_dispatch(__first, __last, _Integral());
    }

      allocator_type
      get_allocator() const
      { return _Base::get_allocator(); }

      // iterators
      iterator
      begin()
      { return iterator(this->_M_impl._M_node._M_next); }

      const_iterator
      begin() const
      { return const_iterator(this->_M_impl._M_node._M_next); }

      iterator
      end()
      { return iterator(&this->_M_impl._M_node); }

      const_iterator
      end() const
      { return const_iterator(&this->_M_impl._M_node); }

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

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

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

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

      // [23.2.2.2] capacity
      bool
      empty() const
      { return this->_M_impl._M_node._M_next == &this->_M_impl._M_node; }

      size_type
      size() const
      { return std::distance(begin(), end()); }

      size_type
      max_size() const
      { return size_type(-1); }

      void
      resize(size_type __new_size, value_type __x = value_type());

      // element access
      reference
      front()
      { return *begin(); }

      const_reference
      front() const
      { return *begin(); }

      reference
      back()
      { 
    iterator __tmp = end();
    --__tmp;
    return *__tmp;
      }

      const_reference
      back() const
      { 
    const_iterator __tmp = end();
    --__tmp;
    return *__tmp;
      }

      // [23.2.2.3] modifiers
      void
      push_front(const value_type& __x)
      { this->_M_insert(begin(), __x); }

      void
      pop_front()
      { this->_M_erase(begin()); }

      void
      push_back(const value_type& __x)
      { this->_M_insert(end(), __x); }

      void
      pop_back()
      { this->_M_erase(iterator(this->_M_impl._M_node._M_prev)); }

      iterator
      insert(iterator __position, const value_type& __x);

      void
      insert(iterator __position, size_type __n, const value_type& __x)
      { _M_fill_insert(__position, __n, __x); }

      template<typename _InputIterator>
        void
        insert(iterator __position, _InputIterator __first,
           _InputIterator __last)
        {
      // Check whether it's an integral type.  If so, it's not an iterator.
      typedef typename std::__is_integer<_InputIterator>::__type _Integral;
      _M_insert_dispatch(__position, __first, __last, _Integral());
    }

      iterator
      erase(iterator __position);

      iterator
      erase(iterator __first, iterator __last)
      {
    while (__first != __last)
      __first = erase(__first);
    return __last;
      }

      void
      swap(list& __x)
      { _List_node_base::swap(this->_M_impl._M_node, __x._M_impl._M_node); }

      void
      clear()
      {
        _Base::_M_clear();
        _Base::_M_init();
      }

      // [23.2.2.4] list operations
      void
      splice(iterator __position, list& __x)
      {
    if (!__x.empty())
      this->_M_transfer(__position, __x.begin(), __x.end());
      }

      void
      splice(iterator __position, list&, iterator __i)
      {
    iterator __j = __i;
    ++__j;
    if (__position == __i || __position == __j)
      return;
    this->_M_transfer(__position, __i, __j);
      }

      void
      splice(iterator __position, list&, iterator __first, iterator __last)
      {
    if (__first != __last)
      this->_M_transfer(__position, __first, __last);
      }

      void
      remove(const _Tp& __value);

      template<typename _Predicate>
      void
      remove_if(_Predicate);

      void
      unique();

      template<typename _BinaryPredicate>
        void
        unique(_BinaryPredicate);

      void
      merge(list& __x);

      template<typename _StrictWeakOrdering>
        void
        merge(list&, _StrictWeakOrdering);

      void
      reverse()
      { this->_M_impl._M_node.reverse(); }

      void
      sort();

      template<typename _StrictWeakOrdering>
        void
        sort(_StrictWeakOrdering);

    protected:
      // Internal assign functions follow.

      // Called by the range assign to implement [23.1.1]/9
      template<typename _Integer>
        void
        _M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
        {
      _M_fill_assign(static_cast<size_type>(__n),
             static_cast<value_type>(__val));
    }

      // Called by the range assign to implement [23.1.1]/9
      template<typename _InputIterator>
        void
        _M_assign_dispatch(_InputIterator __first, _InputIterator __last,
               __false_type);

      // Called by assign(n,t), and the range assign when it turns out
      // to be the same thing.
      void
      _M_fill_assign(size_type __n, const value_type& __val);


      // Internal insert functions follow.

      // Called by the range insert to implement [23.1.1]/9
      template<typename _Integer>
        void
        _M_insert_dispatch(iterator __pos, _Integer __n, _Integer __x,
               __true_type)
        {
      _M_fill_insert(__pos, static_cast<size_type>(__n),
             static_cast<value_type>(__x));
    }

      // Called by the range insert to implement [23.1.1]/9
      template<typename _InputIterator>
        void
        _M_insert_dispatch(iterator __pos,
               _InputIterator __first, _InputIterator __last,
               __false_type)
        {
      for (; __first != __last; ++__first)
        _M_insert(__pos, *__first);
    }

      // Called by insert(p,n,x), and the range insert when it turns out
      // to be the same thing.
      void
      _M_fill_insert(iterator __pos, size_type __n, const value_type& __x)
      {
    for (; __n > 0; --__n)
      _M_insert(__pos, __x);
      }


      // Moves the elements from [first,last) before position.
      void
      _M_transfer(iterator __position, iterator __first, iterator __last)
      { __position._M_node->transfer(__first._M_node, __last._M_node); }

      // Inserts new element at position given and with value given.
      void
      _M_insert(iterator __position, const value_type& __x)
      {
        _Node* __tmp = _M_create_node(__x);
        __tmp->hook(__position._M_node);
      }

      // Erases element at position given.
      void
      _M_erase(iterator __position)
      {
        __position._M_node->unhook();
        _Node* __n = static_cast<_Node*>(__position._M_node);
        _M_get_Tp_allocator().destroy(&__n->_M_data);
        _M_put_node(__n);
      }
    };

  template<typename _Tp, typename _Alloc>
    inline bool
    operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
    {
      typedef typename list<_Tp, _Alloc>::const_iterator const_iterator;
      const_iterator __end1 = __x.end();
      const_iterator __end2 = __y.end();

      const_iterator __i1 = __x.begin();
      const_iterator __i2 = __y.begin();
      while (__i1 != __end1 && __i2 != __end2 && *__i1 == *__i2)
    {
      ++__i1;
      ++__i2;
    }
      return __i1 == __end1 && __i2 == __end2;
    }

  template<typename _Tp, typename _Alloc>
    inline bool
    operator<(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
    { return std::lexicographical_compare(__x.begin(), __x.end(),
                      __y.begin(), __y.end()); }

  template<typename _Tp, typename _Alloc>
    inline bool
    operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
    { return !(__x == __y); }

  template<typename _Tp, typename _Alloc>
    inline bool
    operator>(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
    { return __y < __x; }

  template<typename _Tp, typename _Alloc>
    inline bool
    operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
    { return !(__y < __x); }

  template<typename _Tp, typename _Alloc>
    inline bool
    operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
    { return !(__x < __y); }

  template<typename _Tp, typename _Alloc>
    inline void
    swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
    { __x.swap(__y); }
} // namespace std

#endif /* _LIST_H */

---