deque.tcc

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// Deque implementation (out of line) -*- C++ -*-

// Copyright (C) 2001-2015 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/>.

/*
 *
 * 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) 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/deque.tcc
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{deque}
 */

#ifndef _DEQUE_TCC
#define _DEQUE_TCC 1

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_CONTAINER

#if __cplusplus >= 201103L
  template <typename _Tp, typename _Alloc>
    void
    deque<_Tp, _Alloc>::
    _M_default_initialize()
    {
      _Map_pointer __cur;
      __try
        {
          for (__cur = this->_M_impl._M_start._M_node;
               __cur < this->_M_impl._M_finish._M_node;
               ++__cur)
            std::__uninitialized_default_a(*__cur, *__cur + _S_buffer_size(),
                                           _M_get_Tp_allocator());
          std::__uninitialized_default_a(this->_M_impl._M_finish._M_first,
                                         this->_M_impl._M_finish._M_cur,
                                         _M_get_Tp_allocator());
        }
      __catch(...)
        {
          std::_Destroy(this->_M_impl._M_start, iterator(*__cur, __cur),
                        _M_get_Tp_allocator());
          __throw_exception_again;
        }
    }
#endif

  template <typename _Tp, typename _Alloc>
    deque<_Tp, _Alloc>&
    deque<_Tp, _Alloc>::
    operator=(const deque& __x)
    {
      if (&__x != this)
        {
#if __cplusplus >= 201103L
          if (_Alloc_traits::_S_propagate_on_copy_assign())
            {
              if (!_Alloc_traits::_S_always_equal()
                  && _M_get_Tp_allocator() != __x._M_get_Tp_allocator())
                {
                  // Replacement allocator cannot free existing storage,
                  // so deallocate everything and take copy of __x's data.
                  _M_replace_map(__x, __x.get_allocator());
                  std::__alloc_on_copy(_M_get_Tp_allocator(),
                                       __x._M_get_Tp_allocator());
                  return *this;
                }
              std::__alloc_on_copy(_M_get_Tp_allocator(),
                                   __x._M_get_Tp_allocator());
            }
#endif
          const size_type __len = size();
          if (__len >= __x.size())
            _M_erase_at_end(std::copy(__x.begin(), __x.end(),
                                      this->_M_impl._M_start));
          else
            {
              const_iterator __mid = __x.begin() + difference_type(__len);
              std::copy(__x.begin(), __mid, this->_M_impl._M_start);
              insert(this->_M_impl._M_finish, __mid, __x.end());
            }
        }
      return *this;
    }

#if __cplusplus >= 201103L
  template<typename _Tp, typename _Alloc>
    template<typename... _Args>
      void
      deque<_Tp, _Alloc>::
      emplace_front(_Args&&... __args)
      {
        if (this->_M_impl._M_start._M_cur != this->_M_impl._M_start._M_first)
          {
            _Alloc_traits::construct(this->_M_impl,
                                     this->_M_impl._M_start._M_cur - 1,
                                     std::forward<_Args>(__args)...);
            --this->_M_impl._M_start._M_cur;
          }
        else
          _M_push_front_aux(std::forward<_Args>(__args)...);
      }

  template<typename _Tp, typename _Alloc>
    template<typename... _Args>
      void
      deque<_Tp, _Alloc>::
      emplace_back(_Args&&... __args)
      {
        if (this->_M_impl._M_finish._M_cur
            != this->_M_impl._M_finish._M_last - 1)
          {
            _Alloc_traits::construct(this->_M_impl,
                                     this->_M_impl._M_finish._M_cur,
                                     std::forward<_Args>(__args)...);
            ++this->_M_impl._M_finish._M_cur;
          }
        else
          _M_push_back_aux(std::forward<_Args>(__args)...);
      }
#endif

#if __cplusplus >= 201103L
  template<typename _Tp, typename _Alloc>
    template<typename... _Args>
      typename deque<_Tp, _Alloc>::iterator
      deque<_Tp, _Alloc>::
      emplace(const_iterator __position, _Args&&... __args)
      {
        if (__position._M_cur == this->_M_impl._M_start._M_cur)
          {
            emplace_front(std::forward<_Args>(__args)...);
            return this->_M_impl._M_start;
          }
        else if (__position._M_cur == this->_M_impl._M_finish._M_cur)
          {
            emplace_back(std::forward<_Args>(__args)...);
            iterator __tmp = this->_M_impl._M_finish;
            --__tmp;
            return __tmp;
          }
        else
          return _M_insert_aux(__position._M_const_cast(),
                               std::forward<_Args>(__args)...);
      }
#endif

  template <typename _Tp, typename _Alloc>
    typename deque<_Tp, _Alloc>::iterator
    deque<_Tp, _Alloc>::
#if __cplusplus >= 201103L
    insert(const_iterator __position, const value_type& __x)
#else
    insert(iterator __position, const value_type& __x)
#endif
    {
      if (__position._M_cur == this->_M_impl._M_start._M_cur)
        {
          push_front(__x);
          return this->_M_impl._M_start;
        }
      else if (__position._M_cur == this->_M_impl._M_finish._M_cur)
        {
          push_back(__x);
          iterator __tmp = this->_M_impl._M_finish;
          --__tmp;
          return __tmp;
        }
      else
        return _M_insert_aux(__position._M_const_cast(), __x);
   }

  template <typename _Tp, typename _Alloc>
    typename deque<_Tp, _Alloc>::iterator
    deque<_Tp, _Alloc>::
    _M_erase(iterator __position)
    {
      iterator __next = __position;
      ++__next;
      const difference_type __index = __position - begin();
      if (static_cast<size_type>(__index) < (size() >> 1))
        {
          if (__position != begin())
            _GLIBCXX_MOVE_BACKWARD3(begin(), __position, __next);
          pop_front();
        }
      else
        {
          if (__next != end())
            _GLIBCXX_MOVE3(__next, end(), __position);
          pop_back();
        }
      return begin() + __index;
    }

  template <typename _Tp, typename _Alloc>
    typename deque<_Tp, _Alloc>::iterator
    deque<_Tp, _Alloc>::
    _M_erase(iterator __first, iterator __last)
    {
      if (__first == __last)
        return __first;
      else if (__first == begin() && __last == end())
        {
          clear();
          return end();
        }
      else
        {
          const difference_type __n = __last - __first;
          const difference_type __elems_before = __first - begin();
          if (static_cast<size_type>(__elems_before) <= (size() - __n) / 2)
            {
              if (__first != begin())
                _GLIBCXX_MOVE_BACKWARD3(begin(), __first, __last);
              _M_erase_at_begin(begin() + __n);
            }
          else
            {
              if (__last != end())
                _GLIBCXX_MOVE3(__last, end(), __first);
              _M_erase_at_end(end() - __n);
            }
          return begin() + __elems_before;
        }
    }

  template <typename _Tp, class _Alloc>
    template <typename _InputIterator>
      void
      deque<_Tp, _Alloc>::
      _M_assign_aux(_InputIterator __first, _InputIterator __last,
                    std::input_iterator_tag)
      {
        iterator __cur = begin();
        for (; __first != __last && __cur != end(); ++__cur, ++__first)
          *__cur = *__first;
        if (__first == __last)
          _M_erase_at_end(__cur);
        else
          insert(end(), __first, __last);
      }

  template <typename _Tp, typename _Alloc>
    void
    deque<_Tp, _Alloc>::
    _M_fill_insert(iterator __pos, size_type __n, const value_type& __x)
    {
      if (__pos._M_cur == this->_M_impl._M_start._M_cur)
        {
          iterator __new_start = _M_reserve_elements_at_front(__n);
          __try
            {
              std::__uninitialized_fill_a(__new_start, this->_M_impl._M_start,
                                          __x, _M_get_Tp_allocator());
              this->_M_impl._M_start = __new_start;
            }
          __catch(...)
            {
              _M_destroy_nodes(__new_start._M_node,
                               this->_M_impl._M_start._M_node);
              __throw_exception_again;
            }
        }
      else if (__pos._M_cur == this->_M_impl._M_finish._M_cur)
        {
          iterator __new_finish = _M_reserve_elements_at_back(__n);
          __try
            {
              std::__uninitialized_fill_a(this->_M_impl._M_finish,
                                          __new_finish, __x,
                                          _M_get_Tp_allocator());
              this->_M_impl._M_finish = __new_finish;
            }
          __catch(...)
            {
              _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
                               __new_finish._M_node + 1);
              __throw_exception_again;
            }
        }
      else
        _M_insert_aux(__pos, __n, __x);
    }

#if __cplusplus >= 201103L
  template <typename _Tp, typename _Alloc>
    void
    deque<_Tp, _Alloc>::
    _M_default_append(size_type __n)
    {
      if (__n)
        {
          iterator __new_finish = _M_reserve_elements_at_back(__n);
          __try
            {
              std::__uninitialized_default_a(this->_M_impl._M_finish,
                                             __new_finish,
                                             _M_get_Tp_allocator());
              this->_M_impl._M_finish = __new_finish;
            }
          __catch(...)
            {
              _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
                               __new_finish._M_node + 1);
              __throw_exception_again;
            }
        }
    }

  template <typename _Tp, typename _Alloc>
    bool
    deque<_Tp, _Alloc>::
    _M_shrink_to_fit()
    {
      const difference_type __front_capacity
        = (this->_M_impl._M_start._M_cur - this->_M_impl._M_start._M_first);
      if (__front_capacity == 0)
        return false;

      const difference_type __back_capacity
        = (this->_M_impl._M_finish._M_last - this->_M_impl._M_finish._M_cur);
      if (__front_capacity + __back_capacity < _S_buffer_size())
        return false;

      return std::__shrink_to_fit_aux<deque>::_S_do_it(*this);
    }
#endif

  template <typename _Tp, typename _Alloc>
    void
    deque<_Tp, _Alloc>::
    _M_fill_initialize(const value_type& __value)
    {
      _Map_pointer __cur;
      __try
        {
          for (__cur = this->_M_impl._M_start._M_node;
               __cur < this->_M_impl._M_finish._M_node;
               ++__cur)
            std::__uninitialized_fill_a(*__cur, *__cur + _S_buffer_size(),
                                        __value, _M_get_Tp_allocator());
          std::__uninitialized_fill_a(this->_M_impl._M_finish._M_first,
                                      this->_M_impl._M_finish._M_cur,
                                      __value, _M_get_Tp_allocator());
        }
      __catch(...)
        {
          std::_Destroy(this->_M_impl._M_start, iterator(*__cur, __cur),
                        _M_get_Tp_allocator());
          __throw_exception_again;
        }
    }

  template <typename _Tp, typename _Alloc>
    template <typename _InputIterator>
      void
      deque<_Tp, _Alloc>::
      _M_range_initialize(_InputIterator __first, _InputIterator __last,
                          std::input_iterator_tag)
      {
        this->_M_initialize_map(0);
        __try
          {
            for (; __first != __last; ++__first)
#if __cplusplus >= 201103L
              emplace_back(*__first);
#else
              push_back(*__first);
#endif
          }
        __catch(...)
          {
            clear();
            __throw_exception_again;
          }
      }

  template <typename _Tp, typename _Alloc>
    template <typename _ForwardIterator>
      void
      deque<_Tp, _Alloc>::
      _M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
                          std::forward_iterator_tag)
      {
        const size_type __n = std::distance(__first, __last);
        this->_M_initialize_map(__n);

        _Map_pointer __cur_node;
        __try
          {
            for (__cur_node = this->_M_impl._M_start._M_node;
                 __cur_node < this->_M_impl._M_finish._M_node;
                 ++__cur_node)
              {
                _ForwardIterator __mid = __first;
                std::advance(__mid, _S_buffer_size());
                std::__uninitialized_copy_a(__first, __mid, *__cur_node,
                                            _M_get_Tp_allocator());
                __first = __mid;
              }
            std::__uninitialized_copy_a(__first, __last,
                                        this->_M_impl._M_finish._M_first,
                                        _M_get_Tp_allocator());
          }
        __catch(...)
          {
            std::_Destroy(this->_M_impl._M_start,
                          iterator(*__cur_node, __cur_node),
                          _M_get_Tp_allocator());
            __throw_exception_again;
          }
      }

  // Called only if _M_impl._M_finish._M_cur == _M_impl._M_finish._M_last - 1.
  template<typename _Tp, typename _Alloc>
#if __cplusplus >= 201103L
    template<typename... _Args>
      void
      deque<_Tp, _Alloc>::
      _M_push_back_aux(_Args&&... __args)
#else
      void
      deque<_Tp, _Alloc>::
      _M_push_back_aux(const value_type& __t)
#endif
      {
        _M_reserve_map_at_back();
        *(this->_M_impl._M_finish._M_node + 1) = this->_M_allocate_node();
        __try
          {
#if __cplusplus >= 201103L
            _Alloc_traits::construct(this->_M_impl,
                                     this->_M_impl._M_finish._M_cur,
                                     std::forward<_Args>(__args)...);
#else
            this->_M_impl.construct(this->_M_impl._M_finish._M_cur, __t);
#endif
            this->_M_impl._M_finish._M_set_node(this->_M_impl._M_finish._M_node
                                                + 1);
            this->_M_impl._M_finish._M_cur = this->_M_impl._M_finish._M_first;
          }
        __catch(...)
          {
            _M_deallocate_node(*(this->_M_impl._M_finish._M_node + 1));
            __throw_exception_again;
          }
      }

  // Called only if _M_impl._M_start._M_cur == _M_impl._M_start._M_first.
  template<typename _Tp, typename _Alloc>
#if __cplusplus >= 201103L
    template<typename... _Args>
      void
      deque<_Tp, _Alloc>::
      _M_push_front_aux(_Args&&... __args)
#else
      void
      deque<_Tp, _Alloc>::
      _M_push_front_aux(const value_type& __t)
#endif
      {
        _M_reserve_map_at_front();
        *(this->_M_impl._M_start._M_node - 1) = this->_M_allocate_node();
        __try
          {
            this->_M_impl._M_start._M_set_node(this->_M_impl._M_start._M_node
                                               - 1);
            this->_M_impl._M_start._M_cur = this->_M_impl._M_start._M_last - 1;
#if __cplusplus >= 201103L
            _Alloc_traits::construct(this->_M_impl,
                                     this->_M_impl._M_start._M_cur,
                                     std::forward<_Args>(__args)...);
#else
            this->_M_impl.construct(this->_M_impl._M_start._M_cur, __t);
#endif
          }
        __catch(...)
          {
            ++this->_M_impl._M_start;
            _M_deallocate_node(*(this->_M_impl._M_start._M_node - 1));
            __throw_exception_again;
          }
      }

  // Called only if _M_impl._M_finish._M_cur == _M_impl._M_finish._M_first.
  template <typename _Tp, typename _Alloc>
    void deque<_Tp, _Alloc>::
    _M_pop_back_aux()
    {
      _M_deallocate_node(this->_M_impl._M_finish._M_first);
      this->_M_impl._M_finish._M_set_node(this->_M_impl._M_finish._M_node - 1);
      this->_M_impl._M_finish._M_cur = this->_M_impl._M_finish._M_last - 1;
      _Alloc_traits::destroy(_M_get_Tp_allocator(),
                             this->_M_impl._M_finish._M_cur);
    }

  // Called only if _M_impl._M_start._M_cur == _M_impl._M_start._M_last - 1.
  // Note that if the deque has at least one element (a precondition for this
  // member function), and if
  //   _M_impl._M_start._M_cur == _M_impl._M_start._M_last,
  // then the deque must have at least two nodes.
  template <typename _Tp, typename _Alloc>
    void deque<_Tp, _Alloc>::
    _M_pop_front_aux()
    {
      _Alloc_traits::destroy(_M_get_Tp_allocator(),
                             this->_M_impl._M_start._M_cur);
      _M_deallocate_node(this->_M_impl._M_start._M_first);
      this->_M_impl._M_start._M_set_node(this->_M_impl._M_start._M_node + 1);
      this->_M_impl._M_start._M_cur = this->_M_impl._M_start._M_first;
    }

  template <typename _Tp, typename _Alloc>
    template <typename _InputIterator>
      void
      deque<_Tp, _Alloc>::
      _M_range_insert_aux(iterator __pos,
                          _InputIterator __first, _InputIterator __last,
                          std::input_iterator_tag)
      { std::copy(__first, __last, std::inserter(*this, __pos)); }

  template <typename _Tp, typename _Alloc>
    template <typename _ForwardIterator>
      void
      deque<_Tp, _Alloc>::
      _M_range_insert_aux(iterator __pos,
                          _ForwardIterator __first, _ForwardIterator __last,
                          std::forward_iterator_tag)
      {
        const size_type __n = std::distance(__first, __last);
        if (__pos._M_cur == this->_M_impl._M_start._M_cur)
          {
            iterator __new_start = _M_reserve_elements_at_front(__n);
            __try
              {
                std::__uninitialized_copy_a(__first, __last, __new_start,
                                            _M_get_Tp_allocator());
                this->_M_impl._M_start = __new_start;
              }
            __catch(...)
              {
                _M_destroy_nodes(__new_start._M_node,
                                 this->_M_impl._M_start._M_node);
                __throw_exception_again;
              }
          }
        else if (__pos._M_cur == this->_M_impl._M_finish._M_cur)
          {
            iterator __new_finish = _M_reserve_elements_at_back(__n);
            __try
              {
                std::__uninitialized_copy_a(__first, __last,
                                            this->_M_impl._M_finish,
                                            _M_get_Tp_allocator());
                this->_M_impl._M_finish = __new_finish;
              }
            __catch(...)
              {
                _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
                                 __new_finish._M_node + 1);
                __throw_exception_again;
              }
          }
        else
          _M_insert_aux(__pos, __first, __last, __n);
      }

  template<typename _Tp, typename _Alloc>
#if __cplusplus >= 201103L
    template<typename... _Args>
      typename deque<_Tp, _Alloc>::iterator
      deque<_Tp, _Alloc>::
      _M_insert_aux(iterator __pos, _Args&&... __args)
      {
        value_type __x_copy(std::forward<_Args>(__args)...); // XXX copy
#else
    typename deque<_Tp, _Alloc>::iterator
      deque<_Tp, _Alloc>::
      _M_insert_aux(iterator __pos, const value_type& __x)
      {
        value_type __x_copy = __x; // XXX copy
#endif
        difference_type __index = __pos - this->_M_impl._M_start;
        if (static_cast<size_type>(__index) < size() / 2)
          {
            push_front(_GLIBCXX_MOVE(front()));
            iterator __front1 = this->_M_impl._M_start;
            ++__front1;
            iterator __front2 = __front1;
            ++__front2;
            __pos = this->_M_impl._M_start + __index;
            iterator __pos1 = __pos;
            ++__pos1;
            _GLIBCXX_MOVE3(__front2, __pos1, __front1);
          }
        else
          {
            push_back(_GLIBCXX_MOVE(back()));
            iterator __back1 = this->_M_impl._M_finish;
            --__back1;
            iterator __back2 = __back1;
            --__back2;
            __pos = this->_M_impl._M_start + __index;
            _GLIBCXX_MOVE_BACKWARD3(__pos, __back2, __back1);
          }
        *__pos = _GLIBCXX_MOVE(__x_copy);
        return __pos;
      }

  template <typename _Tp, typename _Alloc>
    void
    deque<_Tp, _Alloc>::
    _M_insert_aux(iterator __pos, size_type __n, const value_type& __x)
    {
      const difference_type __elems_before = __pos - this->_M_impl._M_start;
      const size_type __length = this->size();
      value_type __x_copy = __x;
      if (__elems_before < difference_type(__length / 2))
        {
          iterator __new_start = _M_reserve_elements_at_front(__n);
          iterator __old_start = this->_M_impl._M_start;
          __pos = this->_M_impl._M_start + __elems_before;
          __try
            {
              if (__elems_before >= difference_type(__n))
                {
                  iterator __start_n = (this->_M_impl._M_start
                                        + difference_type(__n));
                  std::__uninitialized_move_a(this->_M_impl._M_start,
                                              __start_n, __new_start,
                                              _M_get_Tp_allocator());
                  this->_M_impl._M_start = __new_start;
                  _GLIBCXX_MOVE3(__start_n, __pos, __old_start);
                  std::fill(__pos - difference_type(__n), __pos, __x_copy);
                }
              else
                {
                  std::__uninitialized_move_fill(this->_M_impl._M_start,
                                                 __pos, __new_start,
                                                 this->_M_impl._M_start,
                                                 __x_copy,
                                                 _M_get_Tp_allocator());
                  this->_M_impl._M_start = __new_start;
                  std::fill(__old_start, __pos, __x_copy);
                }
            }
          __catch(...)
            {
              _M_destroy_nodes(__new_start._M_node,
                               this->_M_impl._M_start._M_node);
              __throw_exception_again;
            }
        }
      else
        {
          iterator __new_finish = _M_reserve_elements_at_back(__n);
          iterator __old_finish = this->_M_impl._M_finish;
          const difference_type __elems_after =
            difference_type(__length) - __elems_before;
          __pos = this->_M_impl._M_finish - __elems_after;
          __try
            {
              if (__elems_after > difference_type(__n))
                {
                  iterator __finish_n = (this->_M_impl._M_finish
                                         - difference_type(__n));
                  std::__uninitialized_move_a(__finish_n,
                                              this->_M_impl._M_finish,
                                              this->_M_impl._M_finish,
                                              _M_get_Tp_allocator());
                  this->_M_impl._M_finish = __new_finish;
                  _GLIBCXX_MOVE_BACKWARD3(__pos, __finish_n, __old_finish);
                  std::fill(__pos, __pos + difference_type(__n), __x_copy);
                }
              else
                {
                  std::__uninitialized_fill_move(this->_M_impl._M_finish,
                                                 __pos + difference_type(__n),
                                                 __x_copy, __pos,
                                                 this->_M_impl._M_finish,
                                                 _M_get_Tp_allocator());
                  this->_M_impl._M_finish = __new_finish;
                  std::fill(__pos, __old_finish, __x_copy);
                }
            }
          __catch(...)
            {
              _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
                               __new_finish._M_node + 1);
              __throw_exception_again;
            }
        }
    }

  template <typename _Tp, typename _Alloc>
    template <typename _ForwardIterator>
      void
      deque<_Tp, _Alloc>::
      _M_insert_aux(iterator __pos,
                    _ForwardIterator __first, _ForwardIterator __last,
                    size_type __n)
      {
        const difference_type __elemsbefore = __pos - this->_M_impl._M_start;
        const size_type __length = size();
        if (static_cast<size_type>(__elemsbefore) < __length / 2)
          {
            iterator __new_start = _M_reserve_elements_at_front(__n);
            iterator __old_start = this->_M_impl._M_start;
            __pos = this->_M_impl._M_start + __elemsbefore;
            __try
              {
                if (__elemsbefore >= difference_type(__n))
                  {
                    iterator __start_n = (this->_M_impl._M_start
                                          + difference_type(__n));
                    std::__uninitialized_move_a(this->_M_impl._M_start,
                                                __start_n, __new_start,
                                                _M_get_Tp_allocator());
                    this->_M_impl._M_start = __new_start;
                    _GLIBCXX_MOVE3(__start_n, __pos, __old_start);
                    std::copy(__first, __last, __pos - difference_type(__n));
                  }
                else
                  {
                    _ForwardIterator __mid = __first;
                    std::advance(__mid, difference_type(__n) - __elemsbefore);
                    std::__uninitialized_move_copy(this->_M_impl._M_start,
                                                   __pos, __first, __mid,
                                                   __new_start,
                                                   _M_get_Tp_allocator());
                    this->_M_impl._M_start = __new_start;
                    std::copy(__mid, __last, __old_start);
                  }
              }
            __catch(...)
              {
                _M_destroy_nodes(__new_start._M_node,
                                 this->_M_impl._M_start._M_node);
                __throw_exception_again;
              }
          }
        else
        {
          iterator __new_finish = _M_reserve_elements_at_back(__n);
          iterator __old_finish = this->_M_impl._M_finish;
          const difference_type __elemsafter =
            difference_type(__length) - __elemsbefore;
          __pos = this->_M_impl._M_finish - __elemsafter;
          __try
            {
              if (__elemsafter > difference_type(__n))
                {
                  iterator __finish_n = (this->_M_impl._M_finish
                                         - difference_type(__n));
                  std::__uninitialized_move_a(__finish_n,
                                              this->_M_impl._M_finish,
                                              this->_M_impl._M_finish,
                                              _M_get_Tp_allocator());
                  this->_M_impl._M_finish = __new_finish;
                  _GLIBCXX_MOVE_BACKWARD3(__pos, __finish_n, __old_finish);
                  std::copy(__first, __last, __pos);
                }
              else
                {
                  _ForwardIterator __mid = __first;
                  std::advance(__mid, __elemsafter);
                  std::__uninitialized_copy_move(__mid, __last, __pos,
                                                 this->_M_impl._M_finish,
                                                 this->_M_impl._M_finish,
                                                 _M_get_Tp_allocator());
                  this->_M_impl._M_finish = __new_finish;
                  std::copy(__first, __mid, __pos);
                }
            }
          __catch(...)
            {
              _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
                               __new_finish._M_node + 1);
              __throw_exception_again;
            }
        }
      }

   template<typename _Tp, typename _Alloc>
     void
     deque<_Tp, _Alloc>::
     _M_destroy_data_aux(iterator __first, iterator __last)
     {
       for (_Map_pointer __node = __first._M_node + 1;
            __node < __last._M_node; ++__node)
         std::_Destroy(*__node, *__node + _S_buffer_size(),
                       _M_get_Tp_allocator());

       if (__first._M_node != __last._M_node)
         {
           std::_Destroy(__first._M_cur, __first._M_last,
                         _M_get_Tp_allocator());
           std::_Destroy(__last._M_first, __last._M_cur,
                         _M_get_Tp_allocator());
         }
       else
         std::_Destroy(__first._M_cur, __last._M_cur,
                       _M_get_Tp_allocator());
     }

  template <typename _Tp, typename _Alloc>
    void
    deque<_Tp, _Alloc>::
    _M_new_elements_at_front(size_type __new_elems)
    {
      if (this->max_size() - this->size() < __new_elems)
        __throw_length_error(__N("deque::_M_new_elements_at_front"));

      const size_type __new_nodes = ((__new_elems + _S_buffer_size() - 1)
                                     / _S_buffer_size());
      _M_reserve_map_at_front(__new_nodes);
      size_type __i;
      __try
        {
          for (__i = 1; __i <= __new_nodes; ++__i)
            *(this->_M_impl._M_start._M_node - __i) = this->_M_allocate_node();
        }
      __catch(...)
        {
          for (size_type __j = 1; __j < __i; ++__j)
            _M_deallocate_node(*(this->_M_impl._M_start._M_node - __j));
          __throw_exception_again;
        }
    }

  template <typename _Tp, typename _Alloc>
    void
    deque<_Tp, _Alloc>::
    _M_new_elements_at_back(size_type __new_elems)
    {
      if (this->max_size() - this->size() < __new_elems)
        __throw_length_error(__N("deque::_M_new_elements_at_back"));

      const size_type __new_nodes = ((__new_elems + _S_buffer_size() - 1)
                                     / _S_buffer_size());
      _M_reserve_map_at_back(__new_nodes);
      size_type __i;
      __try
        {
          for (__i = 1; __i <= __new_nodes; ++__i)
            *(this->_M_impl._M_finish._M_node + __i) = this->_M_allocate_node();
        }
      __catch(...)
        {
          for (size_type __j = 1; __j < __i; ++__j)
            _M_deallocate_node(*(this->_M_impl._M_finish._M_node + __j));
          __throw_exception_again;
        }
    }

  template <typename _Tp, typename _Alloc>
    void
    deque<_Tp, _Alloc>::
    _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front)
    {
      const size_type __old_num_nodes
        = this->_M_impl._M_finish._M_node - this->_M_impl._M_start._M_node + 1;
      const size_type __new_num_nodes = __old_num_nodes + __nodes_to_add;

      _Map_pointer __new_nstart;
      if (this->_M_impl._M_map_size > 2 * __new_num_nodes)
        {
          __new_nstart = this->_M_impl._M_map + (this->_M_impl._M_map_size
                                         - __new_num_nodes) / 2
                         + (__add_at_front ? __nodes_to_add : 0);
          if (__new_nstart < this->_M_impl._M_start._M_node)
            std::copy(this->_M_impl._M_start._M_node,
                      this->_M_impl._M_finish._M_node + 1,
                      __new_nstart);
          else
            std::copy_backward(this->_M_impl._M_start._M_node,
                               this->_M_impl._M_finish._M_node + 1,
                               __new_nstart + __old_num_nodes);
        }
      else
        {
          size_type __new_map_size = this->_M_impl._M_map_size
                                     + std::max(this->_M_impl._M_map_size,
                                                __nodes_to_add) + 2;

          _Map_pointer __new_map = this->_M_allocate_map(__new_map_size);
          __new_nstart = __new_map + (__new_map_size - __new_num_nodes) / 2
                         + (__add_at_front ? __nodes_to_add : 0);
          std::copy(this->_M_impl._M_start._M_node,
                    this->_M_impl._M_finish._M_node + 1,
                    __new_nstart);
          _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);

          this->_M_impl._M_map = __new_map;
          this->_M_impl._M_map_size = __new_map_size;
        }

      this->_M_impl._M_start._M_set_node(__new_nstart);
      this->_M_impl._M_finish._M_set_node(__new_nstart + __old_num_nodes - 1);
    }

  // Overload for deque::iterators, exploiting the "segmented-iterator
  // optimization".
  template<typename _Tp>
    void
    fill(const _Deque_iterator<_Tp, _Tp&, _Tp*>& __first,
         const _Deque_iterator<_Tp, _Tp&, _Tp*>& __last, const _Tp& __value)
    {
      typedef typename _Deque_iterator<_Tp, _Tp&, _Tp*>::_Self _Self;

      for (typename _Self::_Map_pointer __node = __first._M_node + 1;
           __node < __last._M_node; ++__node)
        std::fill(*__node, *__node + _Self::_S_buffer_size(), __value);

      if (__first._M_node != __last._M_node)
        {
          std::fill(__first._M_cur, __first._M_last, __value);
          std::fill(__last._M_first, __last._M_cur, __value);
        }
      else
        std::fill(__first._M_cur, __last._M_cur, __value);
    }

  template<typename _Tp>
    _Deque_iterator<_Tp, _Tp&, _Tp*>
    copy(_Deque_iterator<_Tp, const _Tp&, const _Tp*> __first,
         _Deque_iterator<_Tp, const _Tp&, const _Tp*> __last,
         _Deque_iterator<_Tp, _Tp&, _Tp*> __result)
    {
      typedef typename _Deque_iterator<_Tp, _Tp&, _Tp*>::_Self _Self;
      typedef typename _Self::difference_type difference_type;

      difference_type __len = __last - __first;
      while (__len > 0)
        {
          const difference_type __clen
            = std::min(__len, std::min(__first._M_last - __first._M_cur,
                                       __result._M_last - __result._M_cur));
          std::copy(__first._M_cur, __first._M_cur + __clen, __result._M_cur);
          __first += __clen;
          __result += __clen;
          __len -= __clen;
        }
      return __result;
    }

  template<typename _Tp>
    _Deque_iterator<_Tp, _Tp&, _Tp*>
    copy_backward(_Deque_iterator<_Tp, const _Tp&, const _Tp*> __first,
                  _Deque_iterator<_Tp, const _Tp&, const _Tp*> __last,
                  _Deque_iterator<_Tp, _Tp&, _Tp*> __result)
    {
      typedef typename _Deque_iterator<_Tp, _Tp&, _Tp*>::_Self _Self;
      typedef typename _Self::difference_type difference_type;

      difference_type __len = __last - __first;
      while (__len > 0)
        {
          difference_type __llen = __last._M_cur - __last._M_first;
          _Tp* __lend = __last._M_cur;

          difference_type __rlen = __result._M_cur - __result._M_first;
          _Tp* __rend = __result._M_cur;

          if (!__llen)
            {
              __llen = _Self::_S_buffer_size();
              __lend = *(__last._M_node - 1) + __llen;
            }
          if (!__rlen)
            {
              __rlen = _Self::_S_buffer_size();
              __rend = *(__result._M_node - 1) + __rlen;
            }

          const difference_type __clen = std::min(__len,
                                                  std::min(__llen, __rlen));
          std::copy_backward(__lend - __clen, __lend, __rend);
          __last -= __clen;
          __result -= __clen;
          __len -= __clen;
        }
      return __result;
    }

#if __cplusplus >= 201103L
  template<typename _Tp>
    _Deque_iterator<_Tp, _Tp&, _Tp*>
    move(_Deque_iterator<_Tp, const _Tp&, const _Tp*> __first,
         _Deque_iterator<_Tp, const _Tp&, const _Tp*> __last,
         _Deque_iterator<_Tp, _Tp&, _Tp*> __result)
    {
      typedef typename _Deque_iterator<_Tp, _Tp&, _Tp*>::_Self _Self;
      typedef typename _Self::difference_type difference_type;

      difference_type __len = __last - __first;
      while (__len > 0)
        {
          const difference_type __clen
            = std::min(__len, std::min(__first._M_last - __first._M_cur,
                                       __result._M_last - __result._M_cur));
          std::move(__first._M_cur, __first._M_cur + __clen, __result._M_cur);
          __first += __clen;
          __result += __clen;
          __len -= __clen;
        }
      return __result;
    }

  template<typename _Tp>
    _Deque_iterator<_Tp, _Tp&, _Tp*>
    move_backward(_Deque_iterator<_Tp, const _Tp&, const _Tp*> __first,
                  _Deque_iterator<_Tp, const _Tp&, const _Tp*> __last,
                  _Deque_iterator<_Tp, _Tp&, _Tp*> __result)
    {
      typedef typename _Deque_iterator<_Tp, _Tp&, _Tp*>::_Self _Self;
      typedef typename _Self::difference_type difference_type;

      difference_type __len = __last - __first;
      while (__len > 0)
        {
          difference_type __llen = __last._M_cur - __last._M_first;
          _Tp* __lend = __last._M_cur;

          difference_type __rlen = __result._M_cur - __result._M_first;
          _Tp* __rend = __result._M_cur;

          if (!__llen)
            {
              __llen = _Self::_S_buffer_size();
              __lend = *(__last._M_node - 1) + __llen;
            }
          if (!__rlen)
            {
              __rlen = _Self::_S_buffer_size();
              __rend = *(__result._M_node - 1) + __rlen;
            }

          const difference_type __clen = std::min(__len,
                                                  std::min(__llen, __rlen));
          std::move_backward(__lend - __clen, __lend, __rend);
          __last -= __clen;
          __result -= __clen;
          __len -= __clen;
        }
      return __result;
    }
#endif

_GLIBCXX_END_NAMESPACE_CONTAINER
} // namespace std

#endif