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// Copyright 2015-2019 Hans Dembinski
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt
// or copy at


#include <boost/histogram/fwd.hpp>

namespace boost {
namespace histogram {
namespace axis {

  Lightweight bin view.

  Represents the current bin interval.
template <class Axis>
class interval_view {
  interval_view(const Axis& axis, index_type idx) : axis_(axis), idx_(idx) {}
  // avoid viewing a temporary that goes out of scope
  interval_view(Axis&& axis, index_type idx) = delete;

  /// Return lower edge of bin.
  decltype(auto) lower() const noexcept { return axis_.value(idx_); }
  /// Return upper edge of bin.
  decltype(auto) upper() const noexcept { return axis_.value(idx_ + 1); }
  /// Return center of bin.
  decltype(auto) center() const noexcept { return axis_.value(idx_ + 0.5); }
  /// Return width of bin.
  decltype(auto) width() const noexcept { return upper() - lower(); }

  template <class BinType>
  bool operator==(const BinType& rhs) const noexcept {
    return lower() == rhs.lower() && upper() == rhs.upper();

  template <class BinType>
  bool operator!=(const BinType& rhs) const noexcept {
    return !operator==(rhs);

  const Axis& axis_;
  const index_type idx_;

} // namespace axis
} // namespace histogram
} // namespace boost