Range.hpp

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// This file is part of the Acts project.
//
// Copyright (C) 2019 CERN for the benefit of the Acts project
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
#pragma once
 
#include <iterator>
#include <utility>
 
namespace Jug {
 
/** A wrapper around a pair of iterators to simplify range-based loops.
 *
 *  Some standard library algorithms return pairs of iterators to identify
 *  a sub-range. This wrapper simplifies the iteration and should be used as
 *  follows:
 *
 *      for (auto x : makeRange(std::equal_range(...)) {
 *          ...
 *      }
 */
template <typename Iterator>
class Range {
 public:
  Range(Iterator b, Iterator e) : m_begin(b), m_end(e) {}
  Range(Range&&) = default;
  Range(const Range&) = default;
  ~Range() = default;
  Range& operator=(Range&&) = default;
  Range& operator=(const Range&) = default;
 
  Iterator begin() const { return m_begin; }
  Iterator end() const { return m_end; }
  bool empty() const { return m_begin == m_end; }
  std::size_t size() const { return std::distance(m_begin, m_end); }
 
 private:
  Iterator m_begin;
  Iterator m_end;
};
 
template <typename Iterator>
Range<Iterator> makeRange(Iterator begin, Iterator end) {
  return Range<Iterator>(begin, end);
}
 
template <typename Iterator>
Range<Iterator> makeRange(std::pair<Iterator, Iterator> range) {
  return Range<Iterator>(range.first, range.second);
}
 
}  // namespace Jug