#include <DB/Interpreters/NullableUtils.h>


namespace DB
{

void extractNestedColumnsAndNullMap(ConstColumnPlainPtrs & key_columns, ColumnPtr & null_map_holder, ConstNullMapPtr & null_map)
{
	if (key_columns.size() == 1)
	{
		auto & column = key_columns[0];
		if (!column->isNullable())
			return;

		const ColumnNullable & column_nullable = static_cast<const ColumnNullable &>(*column);
		null_map = &column_nullable.getNullMap();
		column = column_nullable.getNestedColumn().get();
	}
	else
	{
		PaddedPODArray<UInt8> * mutable_null_map = nullptr;

		for (auto & column : key_columns)
		{
			if (column->isNullable())
			{
				const ColumnNullable & column_nullable = static_cast<const ColumnNullable &>(*column);
				column = column_nullable.getNestedColumn().get();

				if (!null_map_holder)
				{
					null_map_holder = column_nullable.getNullMapColumn()->clone();
					mutable_null_map = &static_cast<ColumnUInt8 &>(*null_map_holder).getData();
				}
				else
				{
					const PaddedPODArray<UInt8> & other_null_map = column_nullable.getNullMap();
					for (size_t i = 0, size = mutable_null_map->size(); i < size; ++i)
						(*mutable_null_map)[i] |= other_null_map[i];
				}
			}
		}

		null_map = mutable_null_map;
	}
}

}