SpectrumInfoIterator.h

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2018 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#pragma once
 
#include "MantidAPI/SpectrumInfoItem.h"
#include <boost/iterator/iterator_facade.hpp>
 
using Mantid::API::SpectrumInfoItem;
 
namespace Mantid {
namespace API {
 
template <typename T>
class SpectrumInfoIterator : public boost::iterator_facade<SpectrumInfoIterator<T>, SpectrumInfoItem<T> &,
                                                           boost::random_access_traversal_tag> {
 
public:
  SpectrumInfoIterator(T &spectrumInfo, const size_t index) : m_item(spectrumInfo, index) {}
 
private:
  // Allow boost iterator access
  friend class boost::iterator_core_access;
 
  // Iterator methods
  void advance(int64_t delta) {
    m_item.m_index = delta < 0 ? std::max(static_cast<uint64_t>(0), static_cast<uint64_t>(m_item.m_index) + delta)
                               : std::min(m_item.m_spectrumInfo->size(), m_item.m_index + static_cast<size_t>(delta));
  }
 
  // This could cause a segmentation fault if a user goes past the end of the
  // iterator and tries to index into the n+1 th element (which would not
  // exist). Adding range checks to all the above methods may slow down
  // performance though.
  void increment() {
    if (m_item.m_index < m_item.m_spectrumInfo->size()) {
      ++m_item.m_index;
    }
  }
 
  void decrement() {
    if (m_item.m_index > 0) {
      --m_item.m_index;
    }
  }
 
  size_t getIndex() const { return m_item.m_index; }
 
  void setIndex(const size_t index) { m_item.m_index = index; }
 
  uint64_t distance_to(const SpectrumInfoIterator<T> &other) const {
    return static_cast<uint64_t>(other.getIndex()) - static_cast<uint64_t>(getIndex());
  }
 
  bool equal(const SpectrumInfoIterator<T> &other) const { return getIndex() == other.getIndex(); }
 
  SpectrumInfoItem<T> &dereference() const { return m_item; }
 
  mutable SpectrumInfoItem<T> m_item;
};
 
} // namespace API
} // namespace Mantid