/**
* Compares two nodes for their unique order.
*
* @param node1 first node
* @param node2 node to be compared
* @return {@code 0} if the nodes are identical, or {@code 1}/{@code -1} if the first node appears
* after/before the second
*/
static int diff(final ANode node1, final ANode node2) {
// cache parents of first node
final ANodeList nl = new ANodeList();
for (ANode n = node1; n != null; n = n.parent()) {
if (n == node2) return 1;
nl.add(n);
}
// find lowest common ancestor
ANode c2 = node2;
LOOP:
for (ANode n = node2; (n = n.parent()) != null; ) {
final int is = nl.size();
for (int i = 1; i < is; i++) {
if (n == node1) return -1;
if (!nl.get(i).is(n)) continue;
// check which node appears as first LCA child
final ANode c1 = nl.get(i - 1);
final BasicNodeIter ir = n.children();
for (ANode c; (c = ir.next()) != null; ) {
if (c.is(c1)) return -1;
if (c.is(c2)) return 1;
}
break LOOP;
}
c2 = n;
}
// subtraction is used instead of comparison to support overflow of node id
return node1.id - node2.id < 0 ? -1 : 1;
}
@Override
public Str item(final QueryContext qc, final InputInfo ii) throws QueryException {
ANode node, par = toNode(exprs[0], qc);
do {
node = par;
par = node.parent();
} while (par != null);
final DBNode dbn = toDBNode(node);
return dbn.kind() == Data.DOC ? Str.get(dbn.data().text(dbn.pre(), true)) : Str.ZERO;
}
/**
* Returns a copy of the namespace hierarchy.
*
* @param sc static context (can be {@code null})
* @return namespaces
*/
public final Atts nsScope(final StaticContext sc) {
final Atts ns = new Atts();
ANode node = this;
do {
final Atts nsp = node.namespaces();
if (nsp != null) {
for (int a = nsp.size() - 1; a >= 0; a--) {
final byte[] key = nsp.name(a);
if (!ns.contains(key)) ns.add(key, nsp.value(a));
}
}
node = node.parent();
} while (node != null && node.type == NodeType.ELM);
if (sc != null) sc.ns.inScope(ns);
return ns;
}