/**
* Performs the assert-equals function.
*
* @param ctx query context
* @return resulting value
* @throws QueryException query exception
*/
private Item assertEquals(final QueryContext ctx) throws QueryException {
final byte[] str = expr.length < 3 ? null : checkStr(expr[2], ctx);
final Iter iter1 = ctx.iter(expr[0]), iter2 = ctx.iter(expr[1]);
final Compare comp = new Compare(info);
Item it1, it2;
int c = 1;
while (true) {
it1 = iter1.next();
it2 = iter2.next();
final boolean empty1 = it1 == null, empty2 = it2 == null;
if (empty1 && empty2) return null;
if (empty1 || empty2 || !comp.deep(it1.iter(), it2.iter())) break;
c++;
}
if (str != null) throw UNIT_MESSAGE.get(info, str);
throw new UnitException(info, UNIT_ASSERT_EQUALS, it1, it2, c);
}
