rs-core

Core utilities

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Iterator Base Classes

Core utility library by Ross Smith

#include "rs-core/iterator.hpp"
namespace RS;

Contents

• Iterator Base Classes
  • Contents
  • Iterator base class

Iterator base class

template <typename I, typename CV, typename Guide> class Iterator;

This is a mixin class that can be used to easily create iterators using the CRTP pattern. In the template parameters:

• I is the iterator class being defined.
• CV is either the iterator’s value_type or const value_type depending on whether we want a mutable or constant iterator.
• Guide is a type used to indicate the intended iterator category. It can be one of:
  • One of the standard iterator category tag classes.
  • Another iterator type of the intended category.
  • A range type of the intended category.

The table below shows which operations must be defined for each category of iterator, and which are automatically generated by the mixin base class.

In this table:

• i, j are objects of the iterator type.
• v is an object of the value type.
• n is an integer.

Iterator category	Requires	Defines
Output	i=v	*i ++i i++
Input Forward	*i ++i i==j	i-> i++ i!=j i<=>j
Bidirectional	*i ++i --i i==j	i-> i++ i-- i!=j i<=>j
Random access Contiguous	*i i+=n i-j	i-> i[n] ++i i++ --i i-- i-=n i+n n+i i-n i==j i!=j i<j i>j i<=j i>=j i<=>j

Example:

class MyIterator:
public RS::Iterator<MyIterator, const int, std::forward_iterator_category> {
public:
    const int& operator*() const;
    MyIterator& operator++();
    bool operator==(const MyIterator& i) const;
};