nested_set_subtraction_view.h

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#ifndef MYSQL_SETS_NESTED_SET_SUBTRACTION_VIEW_H
#define MYSQL_SETS_NESTED_SET_SUBTRACTION_VIEW_H
 
/// @file
/// Experimental API header
 
#include "mysql/sets/base_binary_operation_views.h"  // Subtraction_view
#include "mysql/sets/nested_set_binary_operation_view_interface.h"  // Nested_set_binary_operation_view_interface
#include "mysql/sets/nested_set_meta.h"            // Is_nested_set
#include "mysql/sets/set_categories_and_traits.h"  // Is_compatible_set
 
/// @addtogroup GroupLibsMysqlSets
/// @{
 
namespace mysql::sets {
 
/// View over the difference of two nested sets.
///
/// @tparam Source1_tp The first source.
///
/// @tparam Source2_tp The second source.
template <Is_nested_set Source1_tp, Is_nested_set Source2_tp>
  requires Is_compatible_set<Source1_tp, Source2_tp>
class Subtraction_view<Source1_tp, Source2_tp>
    : public detail::Nested_set_binary_operation_view_interface<
          Subtraction_view<Source1_tp, Source2_tp>, Source1_tp, Source2_tp,
          Binary_operation::op_subtraction> {
  using Base_t = detail::Nested_set_binary_operation_view_interface<
      Subtraction_view<Source1_tp, Source2_tp>, Source1_tp, Source2_tp,
      Binary_operation::op_subtraction>;
  using Base_t::m_source1;
  using Base_t::m_source2;
  using Base_t::make_iterator;
 
 public:
  using typename Base_t::Iterator_t;
  using typename Base_t::Key_t;
  using typename Base_t::Source1_t;
  using typename Base_t::Source2_t;
  using Self_t = Subtraction_view<Source1_tp, Source2_tp>;
 
  Subtraction_view() noexcept = default;
 
  /// Construct a new Subtraction_view over the given sources.
  ///
  /// @param source1 The first source.
  ///
  /// @param source2 The second source.
  Subtraction_view(const Source1_t &source1, const Source2_t &source2) noexcept
      : Base_t(source1, source2) {}
 
  /// Construct a new Subtraction_view over the given sources.
  ///
  /// Use this constructor if one of the sources may be empty and you do not
  /// have an object representing it; then pass nullptr for that source.
  ///
  /// @param source1 The first source, or nullptr for empty set.
  ///
  /// @param source2 The second source, or nullptr for empty set.
  Subtraction_view(const Source1_t *source1, const Source2_t *source2) noexcept
      : Base_t(source1, source2) {}
 
  /// @return iterator to the first value pair.
  [[nodiscard]] auto begin() const noexcept {
    return make_iterator(this->m_source1.begin(), this->m_source2.begin());
  }
 
  /// @return iterator to sentinel value pair.
  [[nodiscard]] auto end() const noexcept {
    return make_iterator(this->m_source1.end(), this->m_source2.end());
  }
 
  /// Return iterator to the given key, or end() if not found.
  [[nodiscard]] auto find(const Key_t &key) const noexcept {
    auto it1 = this->m_source1.find(key);
    if (it1 == this->m_source1.end()) return end();
    auto it2 = this->m_source2.find(key);
    if (it2 != this->m_source2.end() && is_subset(it1->second, it2->second))
      return end();
    return make_iterator(it1, it2);
  }
 
  /// Return iterator to the given key, or end() if not found, using the given
  /// iterator cursor as a hint.
  ///
  /// @param[in,out] cursor Hint for the position. The behavior is undefined if
  /// this is greater than the lower bound for the key. It will be updated to
  /// the upper bound for the key.
  ///
  /// @param key Key to search for.
  ///
  /// @return Iterator to the key, or end if not found.
  [[nodiscard]] auto find(Iterator_t &cursor, const Key_t &key) const noexcept {
    auto it1 = this->m_source1.find(cursor.iterator1(), key);
    if (it1 == this->m_source1.end()) return end();
    auto it2 = this->m_source2.find(cursor.iterator2(), key);
    if (it2 != this->m_source2.end() && is_subset(it1->second, it2->second))
      return end();
    return make_iterator(it1, it2);
  }
};  // class Subtraction_view
 
}  // namespace mysql::sets
 
// addtogroup GroupLibsMysqlSets
/// @}
 
#endif  // ifndef MYSQL_SETS_NESTED_SET_SUBTRACTION_VIEW_H