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

// Copyright (C) 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.

#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/formatter.h>

#include <debug/safe_base.h>

#include <bits/stl_pair.h>

#include <bits/cpp_type_traits.h>

namespace __gnu_debug

{

  using std::iterator_traits;

  using std::pair;

  /** 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(); }

  /** \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 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

        };

      /// 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 __is_same<const_iterator, _Safe_iterator>::value;

      }

      typedef iterator_traits<_Iterator> _Traits;

    public:

      typedef _Iterator                           _Base_iterator;

      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.

       * @pre @p x is not singular

       */

      _Safe_iterator(const _Safe_iterator& __x)

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

      {

        _GLIBCXX_DEBUG_VERIFY(!__x._M_singular(),

                              _M_message(__msg_init_copy_singular)

                              ._M_iterator(*this, "this")

                              ._M_iterator(__x, "other"));

      }

      /**

       *  @brief Converting constructor from a mutable iterator to a

       *  constant iterator.

       *

       *  @pre @p x is not singular

      */

      template<typename _MutableIterator>

        _Safe_iterator(

          const _Safe_iterator<_MutableIterator,

          typename std::__enable_if<

                     _Sequence,

                     (std::__are_same<_MutableIterator,

                      typename _Sequence::iterator::_Base_iterator>::__value)

                   >::__type>& __x)

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

        {

          _GLIBCXX_DEBUG_VERIFY(!__x._M_singular(),

                                _M_message(__msg_init_const_singular)

                                ._M_iterator(*this, "this")

                                ._M_iterator(__x, "other"));

        }

      /**

       * @brief Copy assignment.

       * @pre @p x is not singular

       */

      _Safe_iterator&

      operator=(const _Safe_iterator& __x)

      {

        _GLIBCXX_DEBUG_VERIFY(!__x._M_singular(),

                              _M_message(__msg_copy_singular)

                              ._M_iterator(*this, "this")

                              ._M_iterator(__x, "other"));

        _M_current = __x._M_current;

        this->_M_attach(static_cast<_Sequence*>(__x._M_sequence));

        return *this;

      }

      /**

       *  @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(const _Sequence* __seq)

      {

        _Safe_iterator_base::_M_attach(const_cast<_Sequence*>(__seq),

                                       _M_constant());

      }

      /** Invalidate the iterator, making it singular. */

      void

      _M_invalidate();

      /// Is the iterator dereferenceable?

      bool

      _M_dereferenceable() const

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

      /// Is the iterator incrementable?

      bool

      _M_incrementable() const { return this->_M_dereferenceable(); }

      // 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); }

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

     *  precision.

    */

    template<typename _Iterator1, typename _Iterator2>

      static pair<difference_type, _Distance_precision>

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

      {

        typedef typename iterator_traits<_Iterator1>::iterator_category

          _Category;

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

      }

    template<typename _Iterator1, typename _Iterator2>

      static pair<difference_type, _Distance_precision>

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

                      std::random_access_iterator_tag)

      {

        return std::make_pair(__rhs.base() - __lhs.base(), __dp_exact);

      }

    template<typename _Iterator1, typename _Iterator2>

      static pair<difference_type, _Distance_precision>

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

                    std::forward_iterator_tag)

      {

        return std::make_pair(__lhs.base() == __rhs.base()? 0 : 1,

                              __dp_equality);

      }

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

      bool _M_is_begin() const

      { return *this == static_cast<const _Sequence*>(_M_sequence)->begin(); }

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

      bool _M_is_end() const

      { return *this == static_cast<const _Sequence*>(_M_sequence)->end(); }

    };

  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

  // According to the resolution of DR179 not only the various comparison

  // operators but also operator- must accept mixed iterator/const_iterator

  // parameters.

  template<typename _IteratorL, typename _IteratorR, typename _Sequence>

    inline typename _Safe_iterator<_IteratorL, _Sequence>::difference_type

    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_distance_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_distance_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

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

    }

  template<typename _Iterator, typename _Sequence>

    inline _Safe_iterator<_Iterator, _Sequence>

    operator+(typename _Safe_iterator<_Iterator,_Sequence>::difference_type __n,

              const _Safe_iterator<_Iterator, _Sequence>& __i)

    { return __i + __n; }

} // namespace __gnu_debug

#ifndef _GLIBCXX_EXPORT_TEMPLATE

#  include <debug/safe_iterator.tcc>

#endif

#endif