void Channel::move_root_upwards(TileIndex new_root_index, TileIndex old_root_index) {
Tile old_root_tile;
Tile empty_tile;
assert(read_tile(old_root_index, old_root_tile));
TileIndex ti = old_root_index;
while (ti != new_root_index) {
write_tile(ti.sibling(), empty_tile);
write_tile(ti.parent(), old_root_tile);
ti = ti.parent();
}
}
TileIndex Channel::find_successive_tile(TileIndex root, TileIndex ti, int desired_level) const {
// Move upwards until parent has a different end time
while (1) {
if (ti.parent().is_null()) return TileIndex::null();
if (ti.parent().end_time() != ti.end_time()) break;
ti = ti.parent();
if (ti.level >= root.level) {
// No more underneath the root
return TileIndex::null();
}
}
// We are now the left child of our parent; skip to the right child
ti = ti.sibling();
return find_child_overlapping_time(ti, ti.start_time(), desired_level);
}
