/**
* Unshift, or 'push', a vertex onto the front of the list
*
* This is confusing, believe me, but I can explain it:
*
* You start with this -
*
* v1 v2 v3 v4 (edge->getPrev(), edge->getNext())
* \ / \ / \ /
* null -- e1 - e2 - e3 -- null (getNextEdge(), getPreviousEdge())
*
* And end with this -
*
* * v5 v1 v2 v3 v4 (edge->getPrev(), edge->getNext())
* \ / \ / \ / \ /
* null -- e5 - e1 - e2 - e3 -- null (getNextEdge(), getPreviousEdge())
*
* So a new edge (e5) is created, pointing to the new vertex previously and the old vertex in next
*
* @param Falcraft\Data\Types\Node\VertexInterface The vertex to make first
*
* @return int New count of elements (vertices)
*
*/
public function unshiftReference(TypesResource\VertexInterface &$vertex)
{
// Get the beginning of the list and set it as the current edge
$currentEdge =& $this->getFirstEdge();
// $currentEdge = $this->getFirstEdge();
if ($currentEdge->getNextEdge() == null) {
/* First edge is last edge is the only edge
*
* ? ?
* \ /
* null - CE - null
*/
if ($currentEdge->getPrevious() == null) {
/* null ?
* \ /
* CE
*/
// push new value to beginning of list:
$currentEdge->setPrevious($vertex);
return $this->count();
}
if ($currentEdge->getNext() == null) {
/* v1 null
* \ /
* CE
*/
// push new value to the beginning of list:
$currentEdge->setNext($currentEdge->getPrevious());
$currentEdge->setPrevious($vertex);
return $this->count();
}
}
/* v1 v2 new v1 v2
* \ / -> \ /\ /
* CE NE CE
*/
// Construct a new node e5 -> v5 - v1 (v5 is $vertex)
$newEdge = new OrderedEdge($vertex, $currentEdge->getPrevious());
/* append edge on to front of list:
(null - e1 - e2) becomes (null - e5 - e1 - e2) */
OrderedEdge::connect($newEdge, $currentEdge);
// $currentEdge->setPreviousEdge($newEdge);
// $newEdge->setNextEdge($currentEdge);
// Add the edge to the RestrictedSet. Booyah!
$this->edges->addReference($newEdge);
return $this->count();
}
echo "Failure...\n";
}
echo "Instantiate Ordered Edges -> ";
$success = true;
$testOrderedEdge1 = $testOrderedEdge2 = null;
try {
$testOrderedEdge1 = new Types\OrderedEdge($testUnorderedNode1, $testUnorderedNode2);
$testOrderedEdge2 = new Types\OrderedEdge($testUnorderedNode3, $testUnorderedNode4);
} catch (\Exception $e) {
$success = false;
}
if ($success) {
echo "Success!\n";
} else {
echo "Failure...\n";
}
echo "Linking Ordered Edges -> ";
$success = true;
try {
Types\OrderedEdge::connect($testOrderedEdge1, $testOrderedEdge2);
} catch (\Exception $e) {
$success = false;
}
if ($success) {
echo "Success!\n\n";
echo "Test Results\n\n";
echo "testOrderedEdge1 Next (Prev Node, Next Node) -> ";
echo "(" . $testOrderedEdge1->getNextEdge()->getPrevious()->getIdentifier() . ", " . $testOrderedEdge1->getNextEdge()->getNext()->getIdentifier() . ")\n";
echo "testOrderedEdge2 Previous (Prev Node, Next Node) -> ";
echo "(" . $testOrderedEdge2->getPreviousEdge()->getPrevious()->getIdentifier() . ", " . $testOrderedEdge2->getPreviousEdge()->getNext()->getIdentifier() . ")\n";
}