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

// Copyright (C) 2011 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_local_iterator.h

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

 */

#ifndef _GLIBCXX_DEBUG_SAFE_LOCAL_ITERATOR_H

#define _GLIBCXX_DEBUG_SAFE_LOCAL_ITERATOR_H 1

#include <debug/debug.h>

#include <debug/macros.h>

#include <debug/functions.h>

#include <debug/safe_unordered_base.h>

#include <ext/type_traits.h>

namespace __gnu_debug

{

  /** \brief Safe iterator wrapper.

   *

   *  The class template %_Safe_local_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_local_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_local_iterator : public _Safe_local_iterator_base

    {

      typedef _Safe_local_iterator _Self;

      typedef typename _Sequence::size_type size_type;

      /// The underlying iterator

      _Iterator _M_current;

      /// The bucket this local iterator belongs to 

      size_type _M_bucket;

      /// Determine if this is a constant iterator.

      bool

      _M_constant() const

      {

        typedef typename _Sequence::const_local_iterator const_iterator;

        return std::__are_same<const_iterator, _Safe_local_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_local_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_local_iterator(const _Iterator& __i, size_type __bucket,

                           const _Sequence* __seq)

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

        _M_bucket(__bucket)

      {

        _GLIBCXX_DEBUG_VERIFY(!this->_M_singular(),

                              _M_message(__msg_init_singular)

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

      }

      /**

       * @brief Copy construction.

       */

      _Safe_local_iterator(const _Safe_local_iterator& __x)

      : _Safe_local_iterator_base(__x, _M_constant()),

        _M_current(__x._M_current), _M_bucket(__x._M_bucket)

      {

        // _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"));

      }

      /**

       *  @brief Converting constructor from a mutable iterator to a

       *  constant iterator.

      */

      template<typename _MutableIterator>

        _Safe_local_iterator(

          const _Safe_local_iterator<_MutableIterator,

          typename __gnu_cxx::__enable_if<std::__are_same<

              _MutableIterator,

              typename _Sequence::local_iterator::iterator_type>::__value,

                                          _Sequence>::__type>& __x)

        : _Safe_local_iterator_base(__x, _M_constant()),

          _M_current(__x.base()), _M_bucket(__x._M_bucket)

        {

          // _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_local_iterator&

      operator=(const _Safe_local_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;

        _M_bucket = __x._M_bucket;

        this->_M_attach(__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_local_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_local_iterator

      operator++(int)

      {

        _GLIBCXX_DEBUG_VERIFY(this->_M_incrementable(),

                              _M_message(__msg_bad_inc)

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

        _Safe_local_iterator __tmp(*this);

        ++_M_current;

        return __tmp;

      }

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

      /**

       * @brief Return the underlying iterator

       */

      _Iterator

      base() const { return _M_current; }

      /**

       * @brief Return the bucket

       */

      size_type

      bucket() const { return _M_bucket; }

      /**

       * @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(); }

      /// Is the iterator incrementable?

      bool

      _M_incrementable() const

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

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

      template<typename _Other>

        bool

        _M_valid_range(const _Safe_local_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(_M_bucket); }

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

      bool _M_is_end() const

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

      /// Is this iterator part of the same bucket as the other one?

      template <typename _Other>

        bool _M_in_same_bucket(const _Safe_local_iterator<_Other,

                                                _Sequence>& __other) const

        { return _M_bucket == __other.bucket(); }

    };

  template<typename _IteratorL, typename _IteratorR, typename _Sequence>

    inline bool

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

               const _Safe_local_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"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_can_compare(__rhs),

                            _M_message(__msg_compare_different)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_in_same_bucket(__rhs),

                            _M_message(__msg_local_iter_compare_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

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

    }

  template<typename _Iterator, typename _Sequence>

    inline bool

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

               const _Safe_local_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"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_in_same_bucket(__rhs),

                            _M_message(__msg_local_iter_compare_bad)

                            ._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_local_iterator<_IteratorL, _Sequence>& __lhs,

               const _Safe_local_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"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_in_same_bucket(__rhs),

                            _M_message(__msg_local_iter_compare_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

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

    }

  template<typename _Iterator, typename _Sequence>

    inline bool

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

               const _Safe_local_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"));

      _GLIBCXX_DEBUG_VERIFY(__lhs._M_in_same_bucket(__rhs),

                            _M_message(__msg_local_iter_compare_bad)

                            ._M_iterator(__lhs, "lhs")

                            ._M_iterator(__rhs, "rhs"));

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

    }

} // namespace __gnu_debug

#include <debug/safe_local_iterator.tcc>

#endif