gum::ListConstIterator< Val > Class Template Reference

Unsafe but fast const iterators for Lists. More...

#include <agrum/base/core/list.h>

Inheritance diagram for gum::ListConstIterator< Val >:

Public Types
using	iterator_category = std::bidirectional_iterator_tag
	Types for STL compliance.
using	value_type = Val
	Types for STL compliance.
using	reference = Val&
	Types for STL compliance.
using	const_reference = const Val&
	Types for STL compliance.
using	pointer = Val*
	Types for STL compliance.
using	const_pointer = const Val*
	Types for STL compliance.
using	difference_type = std::ptrdiff_t
	Types for STL compliance.

Public Member Functions
Constructors / Destructors
	ListConstIterator () noexcept
	Default constructor.
	ListConstIterator (const List< Val > &theList) noexcept
	Constructor for a begin.
	ListConstIterator (const ListConstIterator< Val > &src) noexcept
	Copy constructor.
	ListConstIterator (ListConstIterator< Val > &&src) noexcept
	Move constructor.
	ListConstIterator (const List< Val > &theList, Size ind_elt)
	Constructor for an iterator pointing to the ind_eltth element of a List.
	~ListConstIterator () noexcept
	Class Desctructor.
Accessors / Modifiers
void	clear () noexcept
	Makes the iterator point toward nothing.
void	setToEnd () noexcept
	Positions the iterator to the end of the list.
bool	isEnd () const noexcept
	Returns a bool indicating whether the iterator points to the end of the list.
Operators
ListConstIterator< Val > &	operator= (const ListConstIterator< Val > &src) noexcept
	Copy operator.
ListConstIterator< Val > &	operator= (ListConstIterator< Val > &&src) noexcept
	Move operator.
ListConstIterator< Val > &	operator++ () noexcept
	Makes the iterator point to the next element in the List.
ListConstIterator< Val > &	operator+= (difference_type i) noexcept
	Makes the iterator point to i elements further in the List.
ListConstIterator< Val > &	operator-- () noexcept
	Makes the iterator point to the preceding element in the List.
ListConstIterator< Val > &	operator-= (difference_type i) noexcept
	Makes the iterator point to i elements befor in the List.
ListConstIterator< Val >	operator+ (difference_type i) noexcept
	Returns a new iterator pointing to i further elements in the gum::List.
ListConstIterator< Val >	operator- (difference_type i) noexcept
	Returns a new iterator pointing to i preceding elements in the gum::List.
bool	operator!= (const ListConstIterator< Val > &src) const noexcept
	Checks whether two iterators point toward different elements.
bool	operator== (const ListConstIterator< Val > &src) const noexcept
	Checks whether two iterators point toward the same elements.
const Val &	operator* () const
	Gives access to the content of the iterator.
const Val *	operator-> () const
	Dereferences the value pointed to by the iterator.

Private Member Functions
ListBucket< Val > *	_getBucket_ () const noexcept
	Returns the bucket the iterator is pointing to.

Private Attributes
ListBucket< Val > *	_bucket_ {nullptr}
	The bucket in the chained list pointed to by the iterator.

Friends
class	List< Val >
	Class List must be a friend because it uses the getBucket method to speed up some processes.

Detailed Description

template<typename Val>
class gum::ListConstIterator< Val >

Unsafe but fast const iterators for Lists.

Class ListConstIterator implements unsafe iterators for List. However, developers may consider using List<x>::const_iterator instead of ListConstIterator<x>.

These iterators are fast but they are unaware of changes within the List. Therefore, if they point to an element that is being deleted from memory by the list, their accessing this element will most probably produce a segmentation fault. Similarly, incrementing or decrementing such an iterator pointing to a deleted element will most certainly produce a mess. So, ListConstIterator should be used only if you are sure that they will never point to an element that has been removed from the list (a typical use is to iterate over a const List). Whenever you are not sure that this property holds, use ListConstIteratorSafe<x> or List<x>::const_iterator_safe. Those iterators are a little bit slower but guarantee that no segmentation fault will ever occur.

Usage example:

// create a list of strings
List<string> list;
list.pushBack ("toto"); list.pushBack ("titi");
 
// parse all the elements of a list
for ( List<string>::const_iterator iter = list.cbegin ();
      iter != list.cend (); ++iter )
  cerr << *iter << endl;
for ( List<string>::const_iterator iter = list.cbegin ();
      iter != list.cend (); iter += 2 ) // step = 2
  cerr << *iter << endl;
for ( List<string>::const_iterator iter = list.cbegin ();
      iter != list.cend (); iter = iter + 2 ) // step = 2
  cerr << *iter << endl;
for ( List<string>::const_iterator iter = list.crbegin ();
      iter != list.crend (); --iter )
  cerr << *iter << endl;
 
// use member size() of the strings
for ( List<string>::const_iterator iter = list.cbegin ();
        iter != list.cend (); ++iter)
  cerr << iter->size() << endl;

Template Parameters

Val	The gum::List values type.

Definition at line 1449 of file list.h.

Member Typedef Documentation

const_pointer

template<typename Val>

using gum::ListConstIterator< Val >::const_pointer = const Val*

Types for STL compliance.

Definition at line 1458 of file list.h.

const_reference

template<typename Val>

using gum::ListConstIterator< Val >::const_reference = const Val&

Types for STL compliance.

Definition at line 1456 of file list.h.

difference_type

template<typename Val>

using gum::ListConstIterator< Val >::difference_type = std::ptrdiff_t

Types for STL compliance.

Definition at line 1459 of file list.h.

iterator_category

template<typename Val>

using gum::ListConstIterator< Val >::iterator_category = std::bidirectional_iterator_tag

Types for STL compliance.

Definition at line 1453 of file list.h.

pointer

template<typename Val>

using gum::ListConstIterator< Val >::pointer = Val*

Types for STL compliance.

Definition at line 1457 of file list.h.

reference

template<typename Val>

using gum::ListConstIterator< Val >::reference = Val&

Types for STL compliance.

Definition at line 1455 of file list.h.

value_type

template<typename Val>

using gum::ListConstIterator< Val >::value_type = Val

Types for STL compliance.

Definition at line 1454 of file list.h.

Constructor & Destructor Documentation

ListConstIterator() [1/5]

template<typename Val>

gum::ListConstIterator< Val >::ListConstIterator ( )

explicitnoexcept

Default constructor.

Returns an iterator pointing toward nothing.

Definition at line 155 of file list_tpl.h.

                                                       {
    // for debugging purposes
    GUM_CONSTRUCTOR(ListConstIterator);
  }

References ListConstIterator().

Referenced by ListConstIterator(), ListConstIterator(), ListConstIterator(), ListConstIterator(), gum::ListIterator< Val >::ListIterator(), gum::ListIterator< Val >::ListIterator(), gum::ListIterator< Val >::ListIterator(), gum::ListIterator< Val >::ListIterator(), gum::ListIterator< Val >::ListIterator(), ~ListConstIterator(), operator!=(), operator+(), operator++(), operator+=(), operator-(), operator--(), operator-=(), operator=(), and operator==().

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ListConstIterator() [2/5]

template<typename Val>

gum::ListConstIterator< Val >::ListConstIterator ( const List< Val > & theList )

noexcept

Constructor for a begin.

Definition at line 162 of file list_tpl.h.

                                                                                 :
      _bucket_{theList._deb_list_} {
    // for debugging purposes
    GUM_CONSTRUCTOR(ListConstIterator);
  }

References _bucket_, and List< Val >.

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ListConstIterator() [3/5]

template<typename Val>

gum::ListConstIterator< Val >::ListConstIterator ( const ListConstIterator< Val > & src )

noexcept

Copy constructor.

Parameters

src	The gum::ListConstIterator to copy.

Definition at line 170 of file list_tpl.h.

                                                                                          :
      _bucket_{src._bucket_} {
    // for debugging purposes
    GUM_CONS_CPY(ListConstIterator);
  }

References ListConstIterator(), and _bucket_.

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ListConstIterator() [4/5]

template<typename Val>

gum::ListConstIterator< Val >::ListConstIterator ( ListConstIterator< Val > && src )

noexcept

Move constructor.

Parameters

src	The gum::ListConstIterator to move.

Definition at line 178 of file list_tpl.h.

                                                                                     :
      _bucket_{std::move(src._bucket_)} {
    // for debugging purposes
    GUM_CONS_MOV(ListConstIterator);
  }

References ListConstIterator(), and _bucket_.

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ListConstIterator() [5/5]

template<typename Val>

gum::ListConstIterator< Val >::ListConstIterator	(	const List< Val > &	theList,
		Size	ind_elt )

Constructor for an iterator pointing to the ind_eltth element of a List.

Parameters

theList	The list to iterate over.
ind_elt	The iterator starting position.

Exceptions

UndefinedIteratorValue

Raised if the element does not exist in the list.

Definition at line 187 of file list_tpl.h.

                                                                                      {
    // for debugging purposes
    GUM_CONSTRUCTOR(ListConstIterator);
 
    // check if the index ind_elt passed as parameter is valid
    if (ind_elt >= theList._nb_elements_) {
      GUM_ERROR(UndefinedIteratorValue, "Not enough elements in the list")
    }
 
    // check if it is faster to find the indexth element from the start or
    // from the end of the list
    if (ind_elt < (theList._nb_elements_ >> 1)) {
      // find the element we shall point to src the start of the list
      for (_bucket_ = theList._deb_list_; ind_elt; --ind_elt, _bucket_ = _bucket_->_next_) {}
    } else {
      // find the element we shall point to src the end of the list
      for (_bucket_ = theList._end_list_, ind_elt = theList._nb_elements_ - ind_elt - 1; ind_elt;
           --ind_elt, _bucket_                    = _bucket_->_prev_) {}
    }
  }

References ListConstIterator(), gum::List< Val >::_nb_elements_, GUM_ERROR, and List< Val >.

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~ListConstIterator()

template<typename Val>

gum::ListConstIterator< Val >::~ListConstIterator ( )

noexcept

Class Desctructor.

Definition at line 210 of file list_tpl.h.

                                                        {
    // for debugging purposes
    GUM_DESTRUCTOR(ListConstIterator);
  }

References ListConstIterator().

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Member Function Documentation

_getBucket_()

template<typename Val>

ListBucket< Val > * gum::ListConstIterator< Val >::_getBucket_ ( ) const

privatenoexcept

Returns the bucket the iterator is pointing to.

Definition at line 238 of file list_tpl.h.

                                                                          {
    return _bucket_;
  }

References _bucket_.

Referenced by gum::List< Val >::_insert_().

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clear()

template<typename Val>

void gum::ListConstIterator< Val >::clear ( )

noexcept

Makes the iterator point toward nothing.

A method for detaching the iterator from the List it is attached to. After being detached, the iterator does not point to any element, i.e., trying to access its content will raise an exception.

Definition at line 244 of file list_tpl.h.

                                                {
    _bucket_ = nullptr;
  }

References _bucket_.

isEnd()

template<typename Val>

bool gum::ListConstIterator< Val >::isEnd ( ) const

noexcept

Returns a bool indicating whether the iterator points to the end of the list.

Returns

Returns a bool indicating whether the iterator points to the end of the list.

Definition at line 257 of file list_tpl.h.

                                                      {
    return (_bucket_ == nullptr);
  }

References _bucket_.

operator!=()

template<typename Val>

bool gum::ListConstIterator< Val >::operator!= ( const ListConstIterator< Val > & src ) const

noexcept

Checks whether two iterators point toward different elements.

Warning

the end and rend iterators are always equal, whatever the list they belong to, i.e., list1.end() == list2.rend().

Parameters

src	The gum::ListConstIterator to test for inequality.

Returns

Returns true if src and this are equal.

Definition at line 321 of file list_tpl.h.

                                                                                            {
    return (_bucket_ != src._bucket_);
  }

References ListConstIterator(), and _bucket_.

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operator*()

template<typename Val>

const Val & gum::ListConstIterator< Val >::operator*

(

)

const

Gives access to the content of the iterator.

Exceptions

UndefinedIteratorValue

Raised if the iterator points to nothing.

Returns

Returns the content of the iterator.

Definition at line 340 of file list_tpl.h.

                                                       {
    if (_bucket_ != nullptr) return _bucket_->_val_;
    else { GUM_ERROR(UndefinedIteratorValue, "Accessing a NULL object") }
  }

References _bucket_, and GUM_ERROR.

Referenced by gum::ListIterator< Val >::operator*(), and gum::ListIterator< Val >::operator*().

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operator+()

template<typename Val>

ListConstIterator< Val > gum::ListConstIterator< Val >::operator+ ( difference_type i )

noexcept

Returns a new iterator pointing to i further elements in the gum::List.

Parameters

i	The number of steps to move the iterator.

Returns

Returns a new gum::ListConstIterator.

Definition at line 307 of file list_tpl.h.

                                                                   {
    return ListConstIterator< Val >(*this) += i;
  }

References ListConstIterator().

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operator++()

template<typename Val>

ListConstIterator< Val > & gum::ListConstIterator< Val >::operator++ ( )

noexcept

Makes the iterator point to the next element in the List.

for (iter = list.begin(); iter != list.end(); ++iter) { }

The above loop is guaranteed to parse the whole List as long as no element is added to or deleted from the List while being in the loop. Runs in constant time.

Returns

Returns this gum::ListConstIterator.

Definition at line 263 of file list_tpl.h.

                                                                          {
    // if we are pointing to an element of the chained list, just
    // point on the next bucket in this list
    if (_bucket_ != nullptr) { _bucket_ = _bucket_->_next_; }
 
    return *this;
  }

References ListConstIterator(), and _bucket_.

Referenced by gum::ListIterator< Val >::operator++().

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operator+=()

template<typename Val>

ListConstIterator< Val > & gum::ListConstIterator< Val >::operator+= ( difference_type i )

noexcept

Makes the iterator point to i elements further in the List.

Parameters

i	The number of steps to move the iterator.

Returns

Returns this gum::ListConstIterator.

Definition at line 273 of file list_tpl.h.

                                                                   {
    if (i >= 0) {
      for (; i && (_bucket_ != nullptr); --i, _bucket_ = _bucket_->_next_) {}
    } else {
      for (; i && (_bucket_ != nullptr); ++i, _bucket_ = _bucket_->_prev_) {}
    }
    return *this;
  }

References ListConstIterator(), and _bucket_.

Referenced by gum::ListIterator< Val >::operator+=().

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operator-()

template<typename Val>

ListConstIterator< Val > gum::ListConstIterator< Val >::operator- ( difference_type i )

noexcept

Returns a new iterator pointing to i preceding elements in the gum::List.

Parameters

i	The number of steps to move the iterator.

Returns

Returns a new gum::ListConstIterator.

Definition at line 314 of file list_tpl.h.

                                                                   {
    return ListConstIterator< Val >(*this) -= i;
  }

References ListConstIterator().

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operator--()

template<typename Val>

ListConstIterator< Val > & gum::ListConstIterator< Val >::operator-- ( )

noexcept

Makes the iterator point to the preceding element in the List.

for (iter = list.rbegin(); iter != list.rend(); --iter) { }

The above loop is guaranteed to parse the whole List as long as no element is added to or deleted from the List while being in the loop. Runs in constant time.

Returns

Returns this gum::ListConstIterator.

Definition at line 285 of file list_tpl.h.

                                                                          {
    // if we are pointing to an element of the chained list, just
    // point on the preceding bucket in this list
    if (_bucket_ != nullptr) { _bucket_ = _bucket_->_prev_; }
 
    return *this;
  }

References ListConstIterator(), and _bucket_.

Referenced by gum::ListIterator< Val >::operator--().

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operator-=()

template<typename Val>

ListConstIterator< Val > & gum::ListConstIterator< Val >::operator-= ( difference_type i )

noexcept

Makes the iterator point to i elements befor in the List.

Parameters

i	The number of steps to move the iterator.

Returns

Returns this gum::ListConstIterator.

Definition at line 295 of file list_tpl.h.

                                                                   {
    if (i >= 0) {
      for (; i && (_bucket_ != nullptr); --i, _bucket_ = _bucket_->_prev_) {}
    } else {
      for (; i && (_bucket_ != nullptr); ++i, _bucket_ = _bucket_->_next_) {}
    }
    return *this;
  }

References ListConstIterator(), and _bucket_.

Referenced by gum::ListIterator< Val >::operator-=().

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operator->()

template<typename Val>

const Val * gum::ListConstIterator< Val >::operator->

(

)

const

Dereferences the value pointed to by the iterator.

Exceptions

UndefinedIteratorValue

Raised if the iterator points to nothing.

Returns

Returns the value pointed to by the iterator.

Definition at line 333 of file list_tpl.h.

                                                        {
    if (_bucket_ != nullptr) return &(_bucket_->_val_);
    else { GUM_ERROR(UndefinedIteratorValue, "Accessing a NULL object") }
  }

References _bucket_, and GUM_ERROR.

Referenced by gum::ListIterator< Val >::operator->(), and gum::ListIterator< Val >::operator->().

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operator=() [1/2]

template<typename Val>

ListConstIterator< Val > & gum::ListConstIterator< Val >::operator= ( const ListConstIterator< Val > & src )

noexcept

Copy operator.

The current iterator now points to the same element as iterator from.

Parameters

src	The gum::ListConstIterator to copy.

Returns

Returns this gum::ListConstIterator.

Definition at line 218 of file list_tpl.h.

                                                                                    {
    // for debugging purposes
    GUM_OP_CPY(ListConstIterator);
 
    _bucket_ = src._bucket_;
    return *this;
  }

Referenced by gum::List< gum::Instantiation * >::List(), and gum::ListIterator< Val >::operator=().

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operator=() [2/2]

template<typename Val>

ListConstIterator< Val > & gum::ListConstIterator< Val >::operator= ( ListConstIterator< Val > && src )

noexcept

Move operator.

Parameters

src	The gum::ListConstIterator to move.

Returns

Returns this gum::ListConstIterator.

Definition at line 229 of file list_tpl.h.

                                                                               {
    // for debugging purposes
    GUM_OP_MOV(ListConstIterator);
    _bucket_ = src._bucket_;
    return *this;
  }

References ListConstIterator().

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operator==()

template<typename Val>

bool gum::ListConstIterator< Val >::operator== ( const ListConstIterator< Val > & src ) const

noexcept

Checks whether two iterators point toward the same elements.

Warning

the end and rend iterators are always equal, whatever the list they belong to, i.e., list1.end() == list2.rend().

Parameters

src	The gum::ListConstIterator to test for equality.

Returns

Returns true if src and this are equal.

Definition at line 327 of file list_tpl.h.

                                                                                            {
    return (_bucket_ == src._bucket_);
  }

References ListConstIterator(), and _bucket_.

Referenced by gum::ListIterator< Val >::operator==().

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setToEnd()

template<typename Val>

void gum::ListConstIterator< Val >::setToEnd ( )

noexcept

Positions the iterator to the end of the list.

Definition at line 250 of file list_tpl.h.

                                                   {
    _bucket_ = nullptr;
  }

References _bucket_.

Friends And Related Symbol Documentation

List< Val >

template<typename Val>

friend class List< Val >

friend

Class List must be a friend because it uses the getBucket method to speed up some processes.

Definition at line 1659 of file list.h.

Referenced by ListConstIterator(), ListConstIterator(), gum::ListIterator< Val >::ListIterator(), and gum::ListIterator< Val >::ListIterator().

Member Data Documentation

_bucket_

template<typename Val>

ListBucket< Val >* gum::ListConstIterator< Val >::_bucket_ {nullptr}

private

The bucket in the chained list pointed to by the iterator.

Definition at line 1671 of file list.h.

{nullptr};

Referenced by ListConstIterator(), ListConstIterator(), ListConstIterator(), _getBucket_(), clear(), isEnd(), operator!=(), operator*(), operator++(), operator+=(), operator--(), operator-=(), operator->(), operator==(), and setToEnd().

---

The documentation for this class was generated from the following files:

• agrum/base/core/list.h
• agrum/base/core/list_tpl.h