#pragma once

#include <lambda/metautils.h>

#include <utility>

namespace lambda {

template <typename Iter, typename Func>

class transform_iterator : std::iterator<std::input_iterator_tag, std::remove_reference_t<decltype(*std::declval<Iter>())>>

{

public:

template <typename _Iter, typename _Func>

transform_iterator(_Iter&& iter, _Func&& func, std::enable_if_t<std::is_convertible<Iter, _Iter>::value && std::is_convertible<Func, _Func>::value>* = 0) :

m_iterator(std::forward<_Iter>(iter)),

m_functor(std::forward<_Func>(func))

{

}

decltype(auto) operator*()

{

return m_functor(*m_iterator);

}

transform_iterator & operator++()

{

++m_iterator;

return *this;

}

bool operator==(const transform_iterator & other) const

{

return m_iterator == other.m_iterator;

}

bool operator!=(const transform_iterator & other) const

{

return m_iterator != other.m_iterator;

}

private:

Iter m_iterator;

Func m_functor;

};

template <typename Iter, typename Func>

transform_iterator<Iter, Func> make_transform_iterator(Iter&& iter, Func&& func)

{

return transform_iterator<Iter, Func>(std::forward<Iter>(iter), std::forward<Func>(func));

}

}