regina::TableView< Element, dim1, dim >::iterator Class Reference

The iterator type for this table view. More...

#include <utilities/tableview.h>

Public Types
using	value_type = std::remove_reference_t<Subview>
	Indicates what type the iterator points to.
using	iterator_category = std::input_iterator_tag
	Declares this to be an input iterator type.
using	difference_type = ptrdiff_t
	The type obtained by subtracting iterators.
using	pointer = const value_type*
	A pointer to value_type.
using	reference = Subview
	The type returned by the dereference operator, which could be by value (for a multi-dimensional table) or by reference (for a one-dimensional table).

Public Member Functions
	iterator ()=default
	Creates a new uninitialised iterator.
	iterator (const iterator &)=default
	Creates a copy of the given iterator.
iterator &	operator= (const iterator &)=default
	Makes this a copy of the given iterator.
bool	operator== (const iterator &rhs) const
	Compares this with the given iterator for equality.
iterator &	operator++ ()
	The preincrement operator.
iterator	operator++ (int)
	The postincrement operator.
iterator &	operator-- ()
	The predecrement operator.
iterator	operator-- (int)
	The postdecrement operator.
Subview	operator* () const
	Returns the subarray or element of the underlying table that this iterator is currently pointing to.

Friends
class	TableView

Detailed Description

template<typename Element, size_t dim1, size_t... dim>
class regina::TableView< Element, dim1, dim >::iterator

The iterator type for this table view.

For a TableView t, an iterator of this type runs through the subarrays/elements t[0], t[1], ..., in order from first to last. See TableView::begin() for further details.

This iterator is, in spirit, a bidirectional multipass iterator. However, we declare it using std::input_iterator_tag here because it does not necessarily return by reference (a requirement of forward and bidirectional iterators in the C++ standard library). In particular:

• For a table with more than one dimension, the dereference operator returns a TableView of smaller dimension, by value. As a result, the reference type is identical to value_type (i.e., a smaller-dimensional TableView).
• For a one-dimensional table, the deference operator returns by reference as usual: value_type is Element, and reference is const Element&.

For most iterator classes, Regina now uses specialisations of std::iterator_traits to provide access to their associated types (e.g., value_type). However, this is not possible for TableView::iterator since TableView is templated. Therefore, for TableView::iterator, we continue to provide these associated types directly as class members.

Both iterator and const_iterator are the same type, since TableView only offers read-only access to the underlying data.

Python

Not present. TableView is an iterable type, but its iter() function returns an object of a different (hidden) iterator class.

Member Typedef Documentation

difference_type

template<typename Element , size_t dim1, size_t... dim>

using regina::TableView< Element, dim1, dim >::iterator::difference_type = ptrdiff_t

The type obtained by subtracting iterators.

iterator_category

template<typename Element , size_t dim1, size_t... dim>

using regina::TableView< Element, dim1, dim >::iterator::iterator_category = std::input_iterator_tag

Declares this to be an input iterator type.

pointer

template<typename Element , size_t dim1, size_t... dim>

using regina::TableView< Element, dim1, dim >::iterator::pointer = const value_type*

A pointer to value_type.

reference

template<typename Element , size_t dim1, size_t... dim>

using regina::TableView< Element, dim1, dim >::iterator::reference = Subview

The type returned by the dereference operator, which could be by value (for a multi-dimensional table) or by reference (for a one-dimensional table).

See the iterator class notes for details.

value_type

template<typename Element , size_t dim1, size_t... dim>

using regina::TableView< Element, dim1, dim >::iterator::value_type = std::remove_reference_t<Subview>

Indicates what type the iterator points to.

Constructor & Destructor Documentation

iterator() [1/2]

template<typename Element , size_t dim1, size_t... dim>

regina::TableView< Element, dim1, dim >::iterator::iterator ( )

default

Creates a new uninitialised iterator.

iterator() [2/2]

template<typename Element , size_t dim1, size_t... dim>

regina::TableView< Element, dim1, dim >::iterator::iterator ( const iterator & )

default

Creates a copy of the given iterator.

Member Function Documentation

operator*()

template<typename Element , size_t dim1, size_t... dim>

Subview regina::TableView< Element, dim1, dim >::iterator::operator* ( ) const

inline

Returns the subarray or element of the underlying table that this iterator is currently pointing to.

The return type follows the same design as TableView::operator[]. For a one-dimensional table it returns the current table element, by const reference. For a multi-dimensional table it returns a TableView of of smaller dimension, by value, representing the slice of the overall table that is obtained when the first array index is fixed at the current iterator position.

Precondition

This iterator is dereferenceable (in particular, it is not past-the-end).

Returns

the corresponding subarray or table element.

operator++() [1/2]

template<typename Element , size_t dim1, size_t... dim>

iterator & regina::TableView< Element, dim1, dim >::iterator::operator++ ( )

inline

The preincrement operator.

Returns

a reference to this iterator after the increment.

operator++() [2/2]

template<typename Element , size_t dim1, size_t... dim>

iterator regina::TableView< Element, dim1, dim >::iterator::operator++ ( int )

inline

The postincrement operator.

Returns

a copy of this iterator before the increment took place.

operator--() [1/2]

template<typename Element , size_t dim1, size_t... dim>

iterator & regina::TableView< Element, dim1, dim >::iterator::operator-- ( )

inline

The predecrement operator.

Returns

a reference to this iterator after the decrement.

operator--() [2/2]

template<typename Element , size_t dim1, size_t... dim>

iterator regina::TableView< Element, dim1, dim >::iterator::operator-- ( int )

inline

The postdecrement operator.

Returns

a copy of this iterator before the decrement took place.

operator=()

template<typename Element , size_t dim1, size_t... dim>

iterator & regina::TableView< Element, dim1, dim >::iterator::operator= ( const iterator & )

default

Makes this a copy of the given iterator.

Returns

a reference to this iterator.

operator==()

template<typename Element , size_t dim1, size_t... dim>

bool regina::TableView< Element, dim1, dim >::iterator::operator== ( const iterator & rhs ) const

inline

Compares this with the given iterator for equality.

Parameters

rhs	the iterator to compare this with.

Returns

true if the iterators point to the same subarray/element of the underlying table, or false if they do not.

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

• utilities/tableview.h