Small cleanup in containers utils

This commit is contained in:
Maxime Coste 2015-02-27 19:32:27 +00:00
parent b480d6b419
commit 31267675b9

View File

@ -86,14 +86,17 @@ FilteredContainer<Container, Filter> filtered(Container&& container, Filter filt
return FilteredContainer<Container, Filter>(container, std::move(filter));
}
template<typename I, typename T>
using TransformedResult = decltype(std::declval<T>()(*std::declval<I>()));
template<typename Iterator, typename Transform>
struct TransformedIterator : std::iterator<std::forward_iterator_tag,
typename std::remove_reference<decltype(std::declval<Transform>()(*std::declval<Iterator>()))>::type>
typename std::remove_reference<TransformedResult<Iterator, Transform>>::type>
{
TransformedIterator(Transform transform, Iterator it)
: m_it(std::move(it)), m_transform(std::move(transform)) {}
auto operator*() -> decltype(std::declval<Transform>()(*std::declval<Iterator>())) { return m_transform(*m_it); }
auto operator*() -> TransformedResult<Iterator, Transform> { return m_transform(*m_it); }
TransformedIterator& operator++() { ++m_it; return *this; }
TransformedIterator operator++(int) { auto copy = *this; ++m_it; return copy; }