/**
* Returns the value of the specified attribute or {@code null}.
*
* @param name attribute to be found
* @return attribute value
*/
public byte[] attribute(final QNm name) {
final BasicNodeIter iter = attributes();
while (true) {
final ANode node = iter.next();
if (node == null) return null;
if (node.qname().eq(name)) return node.string();
}
}
/**
* Recursively finds the uri for the specified prefix.
*
* @param pref prefix
* @return uri
*/
public final byte[] uri(final byte[] pref) {
final Atts at = namespaces();
if (at != null) {
final byte[] s = at.value(pref);
if (s != null) return s;
final ANode n = parent();
if (n != null) return n.uri(pref);
}
return pref.length == 0 ? Token.EMPTY : null;
}
/**
* Parses a string as XML and adds the resulting nodes to the specified parent.
*
* @param value string to parse
* @param elem element
*/
public static void add(final byte[] value, final FElem elem) {
try {
final Parser parser = new XMLParser(new IOContent(value), MainOptions.get(), true);
for (final ANode node : new DBNode(parser).children()) elem.add(node.copy());
} catch (final IOException ex) {
// fallback: add string representation
Util.debug(ex);
elem.add(value);
}
}
/**
* 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;
}
/**
* 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 Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
final ANode node = toEmptyNode(arg(0, qc), qc);
final QNm qname = node != null ? node.qname() : null;
return qname != null ? Uri.uri(qname.uri(), false) : Uri.EMPTY;
}
/**
* Adds children of a sub node.
*
* @param ch child nodes
* @param nb node cache
*/
static void addDesc(final BasicNodeIter ch, final ANodeList nb) {
for (ANode n; (n = ch.next()) != null; ) {
nb.add(n.finish());
addDesc(n.children(), nb);
}
}
/**
* Returns the root of a node (the topmost ancestor without parent node).
*
* @return root node
*/
public final ANode root() {
final ANode p = parent();
return p == null ? this : p.root();
}