Method bit_or

src/common/classes/sparse_bitmap.h:590–711

template <typename T, typename InternalTypes>
SparseBitmap<T, InternalTypes>**
SparseBitmap<T, InternalTypes>::bit_or(SparseBitmap<T, InternalTypes>** bitmap1,
									   SparseBitmap<T, InternalTypes>** bitmap2
)
{
	SparseBitmap *map1, *map2;

	// Handle the case when one or the other of the bitmaps is NULL
	if (!bitmap1 || !(map1 = *bitmap1)) {
		return bitmap2;
	}

	if (!bitmap2 || !(map2 = *bitmap2)) {
		return bitmap1;
	}

	// Make sure we work on 2 different bitmaps
	fb_assert(map1 != map2);

	// First bitmap is singular. Set appropriate bit in second and return it
	if (map1->singular)
	{
		map2->set(map1->singular_value);
		return bitmap2;
	}

	// Second bitmap is singular. Set appropriate bit in first and return it
	if (map2->singular)
	{
		map1->set(map2->singular_value);
		return bitmap1;
	}

	SparseBitmap *source, *dest, **result;

	// If second bitmap seems larger then use it as a target
	if (map2->tree.seemsBiggerThan(map1->tree))
	{
		dest = map2;
		source = map1;
		result = bitmap2;
	}
	else
	{
		dest = map1;
		source = map2;
		result = bitmap1;
	}

	bool sourceFound = source->tree.getFirst();

	// Source bitmap is empty. We have nothing to do thus return.
	if (!sourceFound) {
		return result;
	}

	// Both source and destination are empty. Return destination FWIW.
	bool destFound = dest->tree.getFirst();