Method sortColumns

src/backend/spreadsheet/Spreadsheet.cpp:756–1116

! * Clears all values in the specified columns. * @param cols The columns in the spreadsheet to clear. */

 * @param cols The columns in the spreadsheet to clear.
 */
void Spreadsheet::sortColumns(Column* leading, const QVector<Column*>& cols, bool ascending) {
	DEBUG(Q_FUNC_INFO << ", ascending = " << ascending)
	if (cols.isEmpty())
		return;

	// the normal QPair comparison does not work properly with descending sorting
	// therefore we use our own compare functions
	// TODO: check this. a < b vs. a.first < b.first
	class CompareFunctions {
	public:
		static bool doubleLess(QPair<double, int> a, QPair<double, int> b) {
			return a.first < b.first;
		}
		static bool doubleGreater(QPair<double, int> a, QPair<double, int> b) {
			return a.first > b.first;
		}
		static bool integerLess(QPair<int, int> a, QPair<int, int> b) {
			return a.first < b.first;
		}
		static bool integerGreater(QPair<int, int> a, QPair<int, int> b) {
			return a.first > b.first;
		}
		static bool bigIntLess(QPair<qint64, int> a, QPair<qint64, int> b) {
			return a.first < b.first;
		}
		static bool bigIntGreater(QPair<qint64, int> a, QPair<qint64, int> b) {
			return a.first > b.first;
		}
		static bool QStringLess(const QPair<QString, int>& a, const QPair<QString, int>& b) {
			return a < b;
		}
		static bool QStringGreater(const QPair<QString, int>& a, const QPair<QString, int>& b) {
			return a > b;
		}
		static bool QDateTimeLess(const QPair<QDateTime, int>& a, const QPair<QDateTime, int>& b) {
			return a < b;
		}
		static bool QDateTimeGreater(const QPair<QDateTime, int>& a, const QPair<QDateTime, int>& b) {
			return a > b;
		}
	};

	WAIT_CURSOR;
	beginMacro(i18n("%1: sort columns", name()));

	if (!leading) { // sort separately
		DEBUG("	sort separately")
		for (auto* col : cols) {
			int rows = col->rowCount();
			std::unique_ptr<Column> tempCol(new Column(QStringLiteral("temp"), col->columnMode()));

			switch (col->columnMode()) {
			case AbstractColumn::ColumnMode::Double: {
				QVector<QPair<double, int>> map;

				for (int i = 0; i < rows; i++)
					if (col->isValid(i))
						map.append(QPair<double, int>(col->valueAt(i), i));