cpp-lazy-stream/include/stream/iterator.hpp

//
//  iterator.hpp
//  stream
//
//  Created by Sam Jaffe on 3/28/23.
//

#pragma once
#include "detail/ifd_pointer.hpp"

#include <iterator/facade.h>

namespace stream {
template <typename T> class iterator : public ::iterator::facade<iterator<T>> {
private:
  T (*dereference_)(void *){nullptr};
  bool (*equal_to_)(void *, void *){nullptr};
  void (*increment_)(void *){nullptr};
  char const * type_{nullptr};
  detail::ifd_pointer impl_{};

public:
  iterator() = default;

  template <typename Iter>
  iterator(Iter impl)
      : dereference_([](void * p) -> T { return **((Iter *)p); }),
        equal_to_(
            [](void * l, void * r) { return *((Iter *)l) == *((Iter *)r); }),
        increment_([](void * p) { ++(*(Iter *)(p)); }),
        type_(typeid(Iter).name()), impl_(std::forward<Iter>(impl)) {}

  T dereference() const { return dereference_(impl_.get()); }
  void increment() { increment_(impl_.get()); }
  bool equal_to(iterator const & other) const {
    return impl_ == other.impl_ ||
           (impl_ && other.impl_ && equal_to_(impl_.get(), other.impl_.get()));
  }
};

template <typename Iter>
iterator(Iter) -> iterator<typename std::iterator_traits<Iter>::reference>;
}

MAKE_ITERATOR_FACADE_TYPEDEFS_T(::stream::iterator);