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wpi::iterator_facade_base< DerivedT, IteratorCategoryT, T, DifferenceTypeT, PointerT, ReferenceT > Class Template Reference

CRTP base class which implements the entire standard iterator facade in terms of a minimal subset of the interface. More...

#include <iterator.h>

Inheritance diagram for wpi::iterator_facade_base< DerivedT, IteratorCategoryT, T, DifferenceTypeT, PointerT, ReferenceT >:
wpi::detail::zip_common< ZipType, Iters > wpi::iterator_adaptor_base< DerivedT, WrappedIteratorT, IteratorCategoryT, T, DifferenceTypeT, PointerT, ReferenceT, WrappedTraitsT > wpi::detail::zip_common< zip_first< Iters...>, Iters...> wpi::detail::zip_common< zip_shortest< Iters...>, Iters...> wpi::detail::zip_first< Iters > wpi::detail::zip_shortest< Iters >

Classes

class  ReferenceProxy
 A proxy object for computing a reference via indirecting a copy of an iterator. More...
 

Public Member Functions

DerivedT operator+ (DifferenceTypeT n) const
 
DerivedT operator- (DifferenceTypeT n) const
 
DerivedT & operator++ ()
 
DerivedT operator++ (int)
 
DerivedT & operator-- ()
 
DerivedT operator-- (int)
 
bool operator!= (const DerivedT &RHS) const
 
bool operator> (const DerivedT &RHS) const
 
bool operator<= (const DerivedT &RHS) const
 
bool operator>= (const DerivedT &RHS) const
 
PointerT operator-> ()
 
PointerT operator-> () const
 
ReferenceProxy operator[] (DifferenceTypeT n)
 
ReferenceProxy operator[] (DifferenceTypeT n) const
 

Protected Types

enum  { IsRandomAccess, IsBidirectional }
 

Friends

DerivedT operator+ (DifferenceTypeT n, const DerivedT &i)
 

Detailed Description

template<typename DerivedT, typename IteratorCategoryT, typename T, typename DifferenceTypeT = std::ptrdiff_t, typename PointerT = T *, typename ReferenceT = T &>
class wpi::iterator_facade_base< DerivedT, IteratorCategoryT, T, DifferenceTypeT, PointerT, ReferenceT >

CRTP base class which implements the entire standard iterator facade in terms of a minimal subset of the interface.

Use this when it is reasonable to implement most of the iterator functionality in terms of a core subset. If you need special behavior or there are performance implications for this, you may want to override the relevant members instead.

Note, one abstraction that this does not provide is implementing subtraction in terms of addition by negating the difference. Negation isn't always information preserving, and I can see very reasonable iterator designs where this doesn't work well. It doesn't really force much added boilerplate anyways.

Another abstraction that this doesn't provide is implementing increment in terms of addition of one. These aren't equivalent for all iterator categories, and respecting that adds a lot of complexity for little gain.

Classes wishing to use iterator_facade_base should implement the following methods:

Forward Iterators: (All of the following methods)

  • DerivedT &operator=(const DerivedT &R);
  • bool operator==(const DerivedT &R) const;
  • const T &operator*() const;
  • T &operator*();
  • DerivedT &operator++();

Bidirectional Iterators: (All methods of forward iterators, plus the following)

  • DerivedT &operator--();

Random-access Iterators: (All methods of bidirectional iterators excluding the following)

  • DerivedT &operator++();
  • DerivedT &operator--(); (and plus the following)
  • bool operator<(const DerivedT &RHS) const;
  • DifferenceTypeT operator-(const DerivedT &R) const;
  • DerivedT &operator+=(DifferenceTypeT N);
  • DerivedT &operator-=(DifferenceTypeT N);

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