base_volume.h

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#ifndef MYSQL_SETS_BASE_VOLUME_H
#define MYSQL_SETS_BASE_VOLUME_H
 
/// @file
/// Experimental API header
 
#include "mysql/sets/set_categories_and_traits.h"  // Is_set
 
/// @addtogroup GroupLibsMysqlSets
/// @{
 
namespace mysql::sets {
 
/// Return the volume of the first set minus the volume of the second set.
///
/// This is the default implementation. The result is accurate for set types
/// whose volumes can be represented without loss of precision in the return
/// type from `volume`, i.e., typically set types whose volume does not exceed
/// std::numeric_limits<uint64_t>::max(). Other set types should override this
/// function to avoid precision loss for large sets of almost the same size.
///
/// @tparam Result_t Type of return value. Default is double. The result will be
/// exact if it is at most `mysql::math::max_exact_int<double>`.
///
/// @tparam Set1_t Type of first set.
///
/// @tparam Set2_t Type of second set.
///
/// @param set1 First set.
///
/// @param set2 Second set.
template <class Result_t = double, Is_set Set1_t, Is_set Set2_t>
  requires Is_compatible_set<Set1_t, Set2_t>
[[nodiscard]] Result_t volume_difference(const Set1_t &set1,
                                         const Set2_t &set2) {
  auto c1 = volume(set1);
  auto c2 = volume(set2);
  if (c1 < c2) return -Result_t(c2 - c1);
  return Result_t(c1 - c2);
}
 
}  // namespace mysql::sets
 
// addtogroup GroupLibsMysqlSets
/// @}
 
#endif  // ifndef MYSQL_SETS_BASE_VOLUME_H