cpp-intrusive-list/intrusive_iterator.hpp

//
//  intrusive_iterator.hpp
//  intrusive_list
//
//  Created by Sam Jaffe on 1/7/17.
//

#pragma once

#include <iterator>

template <typename T> class intrusive_list;

template <typename N>
class intrusive_iterator : public std::iterator<std::bidirectional_iterator_tag, typename N::value_type> {
public:
  typedef std::bidirectional_iterator_tag iterator_category;
  typedef typename N::value_type value_type;
  typedef typename N::reference reference;
  typedef typename N::const_reference const_reference;
  typedef typename N::pointer pointer;
  typedef typename N::const_pointer const_pointer;
public:
  intrusive_iterator(N* node);
  operator const_intrusive_iterator<N>() const;
  
  reference operator*();
  const_reference operator*() const;
  
  pointer operator->();
  const_pointer operator->() const;
  
  intrusive_iterator operator++(int);
  intrusive_iterator& operator++();
  
  intrusive_iterator operator--(int);
  intrusive_iterator& operator--();
  
  bool operator==(const intrusive_iterator& other) const;
  bool operator!=(const intrusive_iterator& other) const;
  
private:
  friend intrusive_list<value_type>;
  
  N* get() const;
  N* node_;
};

template <typename N>
class const_intrusive_iterator : public std::iterator<std::bidirectional_iterator_tag, typename N::value_type> {
public:
  typedef std::bidirectional_iterator_tag iterator_category;
  typedef typename N::value_type value_type;
  typedef typename N::reference reference;
  typedef typename N::const_reference const_reference;
  typedef typename N::pointer pointer;
  typedef typename N::const_pointer const_pointer;
public:
  const_intrusive_iterator(N* node);
  
  const_reference operator*() const;
  
  const_pointer operator->() const;
  
  const_intrusive_iterator operator++(int);
  const_intrusive_iterator& operator++();
  
  const_intrusive_iterator operator--(int);
  const_intrusive_iterator& operator--();
  
  bool operator==(const const_intrusive_iterator& other) const;
  bool operator!=(const const_intrusive_iterator& other) const;
  
private:
  friend intrusive_list<value_type>;
  
  N* get() const;
  N* node_;
};