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// Safe iterator implementation  -*- C++ -*-

// Copyright (C) 2003, 2004, 2005, 2006, 2009, 2010, 2011, 2012

// 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/safe_iterator.h

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

 */

#ifndef _GLIBCXX_DEBUG_SAFE_ITERATOR_H

#define _GLIBCXX_DEBUG_SAFE_ITERATOR_H 1

#include <debug/debug.h>

#include <debug/macros.h>

#include <debug/functions.h>

#include <debug/safe_base.h>

#include <bits/stl_pair.h>

#include <ext/type_traits.h>

namespace __gnu_debug

{

  /** Helper struct to deal with sequence offering a before_begin

   *  iterator.

   **/

  template <typename _Sequence>

    struct _BeforeBeginHelper

    {

      typedef typename _Sequence::const_iterator _It;

      typedef typename _It::iterator_type _BaseIt;

      static bool

      _S_Is(_BaseIt, const _Sequence*)

      { return false; }

      static bool

      _S_Is_Beginnest(_BaseIt __it, const _Sequence* __seq)

      { return __it == __seq->_M_base().begin(); }

    };

  /** Iterators that derive from _Safe_iterator_base but that aren't

   *  _Safe_iterators can be determined singular or non-singular via

   *  _Safe_iterator_base.

   */

  inline bool

  __check_singular_aux(const _Safe_iterator_base* __x)

  { return __x->_M_singular(); }

  /** The precision to which we can calculate the distance between

   *  two iterators.

   */

  enum _Distance_precision

    {

      __dp_equality, //< Can compare iterator equality, only

      __dp_sign,     //< Can determine equality and ordering

      __dp_exact     //< Can determine distance precisely

    };

  /** Determine the distance between two iterators with some known

   *    precision.

  */

  template<typename _Iterator1, typename _Iterator2>

    inline std::pair<typename std::iterator_traits<_Iterator1>::difference_type,

                     _Distance_precision>

    __get_distance(const _Iterator1& __lhs, const _Iterator2& __rhs,

                   std::random_access_iterator_tag)

    { return std::make_pair(__rhs - __lhs, __dp_exact); }

  template<typename _Iterator1, typename _Iterator2>

    inline std::pair<typename std::iterator_traits<_Iterator1>::difference_type,

                     _Distance_precision>

    __get_distance(const _Iterator1& __lhs, const _Iterator2& __rhs,

                   std::forward_iterator_tag)

    { return std::make_pair(__lhs == __rhs? 0 : 1, __dp_equality); }

  template<typename _Iterator1, typename _Iterator2>

    inline std::pair<typename std::iterator_traits<_Iterator1>::difference_type,

                     _Distance_precision>

    __get_distance(const _Iterator1& __lhs, const _Iterator2& __rhs)

    {

      typedef typename std::iterator_traits<_Iterator1>::iterator_category

          _Category;

      return __get_distance(__lhs, __rhs, _Category());

    }

  /** \brief Safe iterator wrapper.

   *

   *  The class template %_Safe_iterator is a wrapper around an

   *  iterator that tracks the iterator's movement among sequences and

   *  checks that operations performed on the "safe" iterator are

   *  legal. In additional to the basic iterator operations (which are

   *  validated, and then passed to the underlying iterator),

   *  %_Safe_iterator has member functions for iterator invalidation,

   *  attaching/detaching the iterator from sequences, and querying

   *  the iterator's state.

   */

  template<typename _Iterator, typename _Sequence>

    class _Safe_iterator : public _Safe_iterator_base

    {

      typedef _Safe_iterator _Self;

      /// The underlying iterator

      _Iterator _M_current;

      /// Determine if this is a constant iterator.

      bool

      _M_constant() const

      {

        typedef typename _Sequence::const_iterator const_iterator;

        return std::__are_same<const_iterator, _Safe_iterator>::__value;

      }

      typedef std::iterator_traits<_Iterator> _Traits;

    public:

      typedef _Iterator                           iterator_type;

      typedef typename _Traits::iterator_category iterator_category;

      typedef typename _Traits::value_type        value_type;

      typedef typename _Traits::difference_type   difference_type;

      typedef typename _Traits::reference         reference;

      typedef typename _Traits::pointer           pointer;

      /// @post the iterator is singular and unattached

      _Safe_iterator() : _M_current() { }

      /**

       * @brief Safe iterator construction from an unsafe iterator and

       * its sequence.

       *

       * @pre @p seq is not NULL

       * @post this is not singular

       */

      _Safe_iterator(const _Iterator& __i, const _Sequence* __seq)

      : _Safe_iterator_base(__seq, _M_constant()), _M_current(__i)

      {

        _GLIBCXX_DEBUG_VERIFY(! this->_M_singular(),

                              _M_message(__msg_init_singular)

                              ._M_iterator(*this, "this"));

      }

      /**

       * @brief Copy construction.

       */

      _Safe_iterator(const _Safe_iterator& __x)

      : _Safe_iterator_base(__x, _M_constant()), _M_current(__x._M_current)

      {

        // _GLIBCXX_RESOLVE_LIB_DEFECTS

        // DR 408. Is vector<reverse_iterator<char*> > forbidden?

        _GLIBCXX_DEBUG_VERIFY(!__x._M_singular()

                              || __x._M_current == _Iterator(),

                              _M_message(__msg_init_copy_singular)

                              ._M_iterator(*this, "this")

                              ._M_iterator(__x, "other"));

      }

#if __cplusplus >= 201103L

      /**

       * @brief Move construction.

       * @post __x is singular and unattached

       */

      _Safe_iterator(_Safe_iterator&& __x) : _M_current()

      {

        _GLIBCXX_DEBUG_VERIFY(!__x._M_singular()

                              || __x._M_current == _Iterator(),

                              _M_message(__msg_init_copy_singular)

                              ._M_iterator(*this, "this")

                              ._M_iterator(__x, "other"));

        std::swap(_M_current, __x._M_current);

        this->_M_attach(__x._M_sequence);

        __x._M_detach();

      }

#endif

      /**

       *  @brief Converting constructor from a mutable iterator to a

       *  constant iterator.

      */

      template<typename _MutableIterator>

        _Safe_iterator(

          const _Safe_iterator<_MutableIterator,

          typename __gnu_cxx::__enable_if<(std::__are_same<_MutableIterator,

                      typename _Sequence::iterator::iterator_type>::__value),

                   _Sequence>::__type>& __x)

        : _Safe_iterator_base(__x, _M_constant()), _M_current(__x.base())

        {

          // _GLIBCXX_RESOLVE_LIB_DEFECTS

          // DR 408. Is vector<reverse_iterator<char*> > forbidden?

          _GLIBCXX_DEBUG_VERIFY(!__x._M_singular()

                                || __x.base() == _Iterator(),

                                _M_message(__msg_init_const_singular)

                                ._M_iterator(*this, "this")

                                ._M_iterator(__x, "other"));

        }

      /**

       * @brief Copy assignment.

       */

      _Safe_iterator&

      operator=(const _Safe_iterator& __x)

      {

        // _GLIBCXX_RESOLVE_LIB_DEFECTS

        // DR 408. Is vector<reverse_iterator<char*> > forbidden?

        _GLIBCXX_DEBUG_VERIFY(!__x._M_singular()

                              || __x._M_current == _Iterator(),

                              _M_message(__msg_copy_singular)

                              ._M_iterator(*this, "this")

                              ._M_iterator(__x, "other"));

        _M_current = __x._M_current;

        this->_M_attach(__x._M_sequence);

        return *this;

      }

#if __cplusplus >= 201103L

      /**

       * @brief Move assignment.

       * @post __x is singular and unattached

       */

      _Safe_iterator&

      operator=(_Safe_iterator&& __x)

      {

        _GLIBCXX_DEBUG_VERIFY(this != &__x,

                              _M_message(__msg_self_move_assign)

                              ._M_iterator(*this, "this"));

        _GLIBCXX_DEBUG_VERIFY(!__x._M_singular()

                              || __x._M_current == _Iterator(),

                              _M_message(__msg_copy_singular)

                              ._M_iterator(*this, "this")

                              ._M_iterator(__x, "other"));

        _M_current = __x._M_current;

        _M_attach(__x._M_sequence);

        __x._M_detach();

        __x._M_current = _Iterator();

        return *this;

      }

#endif

      /**

       *  @brief Iterator dereference.

       *  @pre iterator is dereferenceable

       */

      reference

      operator*() const

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_dereferenceable(),

                              _M_message(__msg_bad_deref)

                              ._M_iterator(*this, "this"));

        return *_M_current;

      }

      /**

       *  @brief Iterator dereference.

       *  @pre iterator is dereferenceable

       *  @todo Make this correct w.r.t. iterators that return proxies

       *  @todo Use addressof() instead of & operator

       */

      pointer

      operator->() const

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_dereferenceable(),

                              _M_message(__msg_bad_deref)

                              ._M_iterator(*this, "this"));

        return &*_M_current;

      }

      // ------ Input iterator requirements ------

      /**

       *  @brief Iterator preincrement

       *  @pre iterator is incrementable

       */

      _Safe_iterator&

      operator++()

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(),

                              _M_message(__msg_bad_inc)

                              ._M_iterator(*this, "this"));

        ++_M_current;

        return *this;

      }

      /**

       *  @brief Iterator postincrement

       *  @pre iterator is incrementable

       */

      _Safe_iterator

      operator++(int)

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(),

                              _M_message(__msg_bad_inc)

                              ._M_iterator(*this, "this"));

        _Safe_iterator __tmp(*this);

        ++_M_current;

        return __tmp;

      }

      // ------ Bidirectional iterator requirements ------

      /**

       *  @brief Iterator predecrement

       *  @pre iterator is decrementable

       */

      _Safe_iterator&

      operator--()

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_decrementable(),

                              _M_message(__msg_bad_dec)

                              ._M_iterator(*this, "this"));

        --_M_current;

        return *this;

      }

      /**

       *  @brief Iterator postdecrement

       *  @pre iterator is decrementable

       */

      _Safe_iterator

      operator--(int)

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_decrementable(),

                              _M_message(__msg_bad_dec)

                              ._M_iterator(*this, "this"));

        _Safe_iterator __tmp(*this);

        --_M_current;

        return __tmp;

      }

      // ------ Random access iterator requirements ------

      reference

      operator[](const difference_type& __n) const

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_can_advance(__n)

                              && this->_M_can_advance(__n+1),

                              _M_message(__msg_iter_subscript_oob)

                              ._M_iterator(*this)._M_integer(__n));

        return _M_current[__n];

      }

      _Safe_iterator&

      operator+=(const difference_type& __n)

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_can_advance(__n),

                              _M_message(__msg_advance_oob)

                              ._M_iterator(*this)._M_integer(__n));

        _M_current += __n;

        return *this;

      }

      _Safe_iterator

      operator+(const difference_type& __n) const

      {

        _Safe_iterator __tmp(*this);

        __tmp += __n;

        return __tmp;

      }

      _Safe_iterator&

      operator-=(const difference_type& __n)

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_can_advance(-__n),

                              _M_message(__msg_retreat_oob)

                              ._M_iterator(*this)._M_integer(__n));

        _M_current += -__n;

        return *this;

      }

      _Safe_iterator

      operator-(const difference_type& __n) const

      {

        _Safe_iterator __tmp(*this);

        __tmp -= __n;

        return __tmp;

      }

      // ------ Utilities ------

      /**

       * @brief Return the underlying iterator

       */

      _Iterator

      base() const { return _M_current; }

      /**

       * @brief Conversion to underlying non-debug iterator to allow

       * better interaction with non-debug containers.

       */

      operator _Iterator() const { return _M_current; }

      /** Attach iterator to the given sequence. */

      void

      _M_attach(_Safe_sequence_base* __seq)

      {

        _Safe_iterator_base::_M_attach(__seq, _M_constant());

      }

      /** Likewise, but not thread-safe. */

      void

      _M_attach_single(_Safe_sequence_base* __seq)

      {

        _Safe_iterator_base::_M_attach_single(__seq, _M_constant());

      }

      /// Is the iterator dereferenceable?

      bool

      _M_dereferenceable() const

      { return !this->_M_singular() && !_M_is_end() && !_M_is_before_begin(); }

      /// Is the iterator before a dereferenceable one?

      bool

      _M_before_dereferenceable() const

      {

        if (this->_M_incrementable())

        {

          _Iterator __base = base();

          return ++__base != _M_get_sequence()->_M_base().end();

        }

        return false;

      }

      /// Is the iterator incrementable?

      bool

      _M_incrementable() const

      { return !this->_M_singular() && !_M_is_end(); }

      // Is the iterator decrementable?

      bool

      _M_decrementable() const { return !_M_singular() && !_M_is_begin(); }

      // Can we advance the iterator @p __n steps (@p __n may be negative)

      bool

      _M_can_advance(const difference_type& __n) const;

      // Is the iterator range [*this, __rhs) valid?

      template<typename _Other>

        bool

        _M_valid_range(const _Safe_iterator<_Other, _Sequence>& __rhs) const;

      // The sequence this iterator references.

      const _Sequence*

      _M_get_sequence() const

      { return static_cast<const _Sequence*>(_M_sequence); }

      /// Is this iterator equal to the sequence's begin() iterator?

      bool _M_is_begin() const

      { return base() == _M_get_sequence()->_M_base().begin(); }

      /// Is this iterator equal to the sequence's end() iterator?

      bool _M_is_end() const

      { return base() == _M_get_sequence()->_M_base().end(); }

      /// Is this iterator equal to the sequence's before_begin() iterator if

      /// any?

      bool _M_is_before_begin() const

      {

        return _BeforeBeginHelper<_Sequence>::_S_Is(base(), _M_get_sequence());

      }

      /// Is this iterator equal to the sequence's before_begin() iterator if

      /// any or begin() otherwise?

      bool _M_is_beginnest() const

      {

        return _BeforeBeginHelper<_Sequence>::_S_Is_Beginnest(base(),

                                                          _M_get_sequence());

      }

    };

  template<typename _IteratorL, typename _IteratorR, typename _Sequence>

    inline bool

    operator==(const _Safe_iterator<_IteratorL, _Sequence>& __lhs,

               const _Safe_iterator<_IteratorR, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_compare_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_compare_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() == __rhs.base();

    }

  template<typename _Iterator, typename _Sequence>

    inline bool

    operator==(const _Safe_iterator<_Iterator, _Sequence>& __lhs,

               const _Safe_iterator<_Iterator, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_compare_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_compare_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() == __rhs.base();

    }

  template<typename _IteratorL, typename _IteratorR, typename _Sequence>

    inline bool

    operator!=(const _Safe_iterator<_IteratorL, _Sequence>& __lhs,

               const _Safe_iterator<_IteratorR, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_compare_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_compare_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() != __rhs.base();

    }

  template<typename _Iterator, typename _Sequence>

    inline bool

    operator!=(const _Safe_iterator<_Iterator, _Sequence>& __lhs,

               const _Safe_iterator<_Iterator, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_compare_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_compare_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() != __rhs.base();

    }

  template<typename _IteratorL, typename _IteratorR, typename _Sequence>

    inline bool

    operator<(const _Safe_iterator<_IteratorL, _Sequence>& __lhs,

              const _Safe_iterator<_IteratorR, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_order_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_order_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() < __rhs.base();

    }

  template<typename _Iterator, typename _Sequence>

    inline bool

    operator<(const _Safe_iterator<_Iterator, _Sequence>& __lhs,

              const _Safe_iterator<_Iterator, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_order_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_order_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() < __rhs.base();

    }

  template<typename _IteratorL, typename _IteratorR, typename _Sequence>

    inline bool

    operator<=(const _Safe_iterator<_IteratorL, _Sequence>& __lhs,

               const _Safe_iterator<_IteratorR, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_order_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_order_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() <= __rhs.base();

    }

  template<typename _Iterator, typename _Sequence>

    inline bool

    operator<=(const _Safe_iterator<_Iterator, _Sequence>& __lhs,

               const _Safe_iterator<_Iterator, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_order_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_order_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() <= __rhs.base();

    }

  template<typename _IteratorL, typename _IteratorR, typename _Sequence>

    inline bool

    operator>(const _Safe_iterator<_IteratorL, _Sequence>& __lhs,

              const _Safe_iterator<_IteratorR, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_order_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_order_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() > __rhs.base();

    }

  template<typename _Iterator, typename _Sequence>

    inline bool

    operator>(const _Safe_iterator<_Iterator, _Sequence>& __lhs,

              const _Safe_iterator<_Iterator, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_order_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_order_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() > __rhs.base();

    }

  template<typename _IteratorL, typename _IteratorR, typename _Sequence>

    inline bool

    operator>=(const _Safe_iterator<_IteratorL, _Sequence>& __lhs,

               const _Safe_iterator<_IteratorR, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_order_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_order_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() >= __rhs.base();

    }

  template<typename _Iterator, typename _Sequence>

    inline bool

    operator>=(const _Safe_iterator<_Iterator, _Sequence>& __lhs,

               const _Safe_iterator<_Iterator, _Sequence>& __rhs)

    {

      _GLIBCXX_DEBUG_VERIFY(! __lhs._M_singular() && ! __rhs._M_singular(),

                            _M_message(__msg_iter_order_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_order_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      return __lhs.base() >= __rhs.base();

    }

  // _GLIBCXX_RESOLVE_LIB_DEFECTS