Class UnwrappingIterator

tensorflow/compiler/xla/iterator_util.h:59–89

// input_iterator -- it doesn't inherit any superpowers NestedIterator may have.
template <typename NestedIter>
class UnwrappingIterator
    : public std::iterator<std::input_iterator_tag,
                           decltype(std::declval<NestedIter>()->get())> {
 private:
  NestedIter iter_;

 public:
  explicit UnwrappingIterator(NestedIter iter) : iter_(std::move(iter)) {}

  auto operator*() -> decltype(iter_->get()) { return iter_->get(); }
  auto operator-> () -> decltype(iter_->get()) { return iter_->get(); }
  UnwrappingIterator& operator++() {
    ++iter_;
    return *this;
  }
  UnwrappingIterator operator++(int) {
    UnwrappingIterator temp(iter_);
    operator++();
    return temp;
  }

  friend bool operator==(const UnwrappingIterator& a,
                         const UnwrappingIterator& b) {
    return a.iter_ == b.iter_;
  }

  friend bool operator!=(const UnwrappingIterator& a,
                         const UnwrappingIterator& b) {
    return !(a == b);
  }
};

template <typename NestedIter>
UnwrappingIterator<NestedIter> MakeUnwrappingIterator(NestedIter iter) {