safe_iterator.h

mingw32.rar

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

// Copyright (C) 2003, 2004
// 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// 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 <bits/stl_pair.h>
#include <debug/debug.h>
#include <debug/formatter.h>
#include <debug/safe_base.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>::_M_type)
                   >::_M_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; }