// This provides a very simple, boring adaptor for a begin and end iterator
// into a range type. This should be used to build range views that work well
// with range based for loops and range based constructors.
//
// Note that code here follows more standards-based coding conventions as it
// is mirroring proposed interfaces for standardization.
//
// Converted from chandlerc@'s code to Google style by joshl@.

#ifndef TENSORFLOW_LIB_GTL_ITERATOR_RANGE_H_
#define TENSORFLOW_LIB_GTL_ITERATOR_RANGE_H_

#include <utility>

namespace tensorflow {
namespace gtl {

// A range adaptor for a pair of iterators.
//
// This just wraps two iterators into a range-compatible interface. Nothing
// fancy at all.
template <typename IteratorT>
class iterator_range {
 public:
  iterator_range() : begin_iterator_(), end_iterator_() {}
  iterator_range(IteratorT begin_iterator, IteratorT end_iterator)
      : begin_iterator_(std::move(begin_iterator)),
        end_iterator_(std::move(end_iterator)) {}

  IteratorT begin() const { return begin_iterator_; }
  IteratorT end() const { return end_iterator_; }

 private:
  IteratorT begin_iterator_, end_iterator_;
};

// Convenience function for iterating over sub-ranges.
//
// This provides a bit of syntactic sugar to make using sub-ranges
// in for loops a bit easier. Analogous to std::make_pair().
template <class T>
iterator_range<T> make_range(T x, T y) {
  return iterator_range<T>(std::move(x), std::move(y));
}

}  // namespace gtl
}  // namespace tensorflow

#endif  // TENSORFLOW_LIB_GTL_ITERATOR_RANGE_H_