File indexing completed on 2024-05-05 04:38:42

 /*
     SPDX-FileCopyrightText: 2020 Igor Kushnir <igorkuo@gmail.com>
 
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
 #ifndef KDEVPLATFORM_ALGORITHM_H
 #define KDEVPLATFORM_ALGORITHM_H
 
 #include <QSet>
 
 #include <algorithm>
 #include <iterator>
 #include <type_traits>
 #include <vector>
 
 namespace Algorithm {
 /**
  * Computes the union of the QSet range [first, last) efficiently.
  *
  * @note Pass move iterators to this function if possible. Otherwise the largest set will be
  * detached and copied if there is more than one non-empty set in the range [first, last).
  */
 template <typename ForwardIt>
 auto unite(ForwardIt first, ForwardIt last)
 {
     if (first == last) {
         return std::remove_cv_t<std::remove_reference_t<decltype(*first)>>{};
     }
     const auto maxElement = std::max_element(first, last, [](const auto& a, const auto& b) {
         return a.size() < b.size();
     });
     Q_ASSERT(maxElement != last);
 
     // Start with the largest-size set. None of this set's elements is inserted
     // into another set, so picking the largest one achieves optimum performance.
     auto result = *maxElement;
     for ( ; first != maxElement; ++first) {
         result.unite(*first);
     }
     // skip the already included *maxElement
     for (++first; first != last; ++first) {
         result.unite(*first);
     }
     return result;
 }
 
 /**
  * This is an overloaded convenience function.
  */
 template <typename T>
 QSet<T> unite(std::vector<QSet<T>>&& sets)
 {
     return unite(std::make_move_iterator(sets.begin()),
                  std::make_move_iterator(sets.end()));
 }
 }
 
 #endif // KDEVPLATFORM_ALGORITHM_H