void recursivelyMarkIf(Node* start, const NodeConditional& nc) {
if (nc(&*start)) {
start->mark |= MARK_KEEP | MARK_KEEP_KIDS;
for (ChildIterator ci = childBegin(start); !ci.done(); ++ci) {
recursivelyMarkIf(&*ci, nc);
}
} else {
start->mark |= MARK_KEEP;
}
}
/*!
Destroys children of nodes that are not marked,
defragments the node array
always keeps the root
Note: invalidates all pointers to nodes of the tree, and all
iterators.
*/
void eraseChildrenOfUnmarkedNodes() {
unsigned int write = 0;
nodes[root_index].mark = MARK_KEEP;
assert(root_index < allocation_index);
for (unsigned int read = root_index; read != allocation_index; read++) {
Node *node = &nodes[read];
char mark = node->mark;
if (mark) {
// TODO: could handle read == write as a special case
Node *write_node = &nodes[write];
*write_node = *node; // copy
write_node->mark = 0; // clear mark
if (mark & MARK_KEEP_KIDS) {
// adjust children's parent pointers
for (ChildIterator it = childBegin(write_node); !it.done(); ++it) {
it->parent = write;
}
} else {
write_node->num_children = 0;
}
// adjust parent's first_child "pointer" if this is its first child
if (read != root_index) {
Node* parent_node = getParent(node);
if (write < parent_node->first_child) {
parent_node->first_child = write;
}
}
write++;
}
}
root_index = 0;
nodes[root_index].parent = 0;
allocation_index = write;
}
