ceph/src/boost/boost/histogram/axis/iterator.hpp

   1 // Copyright 2015-2017 Hans Dembinski
   2 //
   3 // Distributed under the Boost Software License, Version 1.0.
   4 // (See accompanying file LICENSE_1_0.txt
   5 // or copy at http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #ifndef BOOST_HISTOGRAM_AXIS_ITERATOR_HPP
   8 #define BOOST_HISTOGRAM_AXIS_ITERATOR_HPP
   9
  10 #include <boost/histogram/axis/interval_view.hpp>
  11 #include <boost/histogram/detail/iterator_adaptor.hpp>
  12 #include <iterator>
  13
  14 namespace boost {
  15 namespace histogram {
  16 namespace axis {
  17
  18 template <class Axis>
  19 class iterator : public detail::iterator_adaptor<iterator<Axis>, index_type,
  20                                                  decltype(std::declval<Axis>().bin(0))> {
  21 public:
  22   /// Make iterator from axis and index.
  23   iterator(const Axis& axis, index_type idx)
  24       : iterator::iterator_adaptor_(idx), axis_(axis) {}
  25
  26   /// Return current bin object.
  27   decltype(auto) operator*() const { return axis_.bin(this->base()); }
  28
  29 private:
  30   const Axis& axis_;
  31 };
  32
  33 /// Uses CRTP to inject iterator logic into Derived.
  34 template <class Derived>
  35 class iterator_mixin {
  36 public:
  37   using const_iterator = iterator<Derived>;
  38   using const_reverse_iterator = std::reverse_iterator<const_iterator>;
  39
  40   /// Bin iterator to beginning of the axis (read-only).
  41   const_iterator begin() const noexcept {
  42     return const_iterator(*static_cast<const Derived*>(this), 0);
  43   }
  44
  45   /// Bin iterator to the end of the axis (read-only).
  46   const_iterator end() const noexcept {
  47     return const_iterator(*static_cast<const Derived*>(this),
  48                           static_cast<const Derived*>(this)->size());
  49   }
  50
  51   /// Reverse bin iterator to the last entry of the axis (read-only).
  52   const_reverse_iterator rbegin() const noexcept {
  53     return std::make_reverse_iterator(end());
  54   }
  55
  56   /// Reverse bin iterator to the end (read-only).
  57   const_reverse_iterator rend() const noexcept {
  58     return std::make_reverse_iterator(begin());
  59   }
  60 };
  61
  62 } // namespace axis
  63 } // namespace histogram
  64 } // namespace boost
  65
  66 #endif