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() . ", " . $testOrderedEdge2->getPreviousEdge()->getNext()->getIdentifier() . ")\n";
}
/**
* Insert a vertex before a vertex identified by identifier
*
* This is why the vertices having identifiers really matter.
* This capability is why you'd use this structure in the first
* place... mostly.
*
* So, what do we got?
*
* You start with this -
*
* v1 v2 v3 v4 (edge->getPrev(), edge->getNext())
* \ / \ / \ /
* null -- e1 - e2 - e3 -- null (getNextEdge(), getPreviousEdge())
*
* And end with this (insert new vertex v5 before v3) -
*
* v1 v2 v5 v3 v4 (edge->getPrev(), edge->getNext())
* \ / \ / \ / \ /
* null -- e1 - e2 - e4 - e3 -- null (getNextEdge(), getPreviousEdge())
*
* First we build a new edge e4 pointing to v5 (new) - v3 (old)
* Then we insert the edge:
* e2 [next] = v5 now, not v3
* e2 [nextEdge] = e4, not e3
* e3 [prevEdge] = e4, not e2
*
* OR!
*
* You start with this -
*
* v1 v2 v3 v4 (edge->getPrev(), edge->getNext())
* \ / \ / \ /
* null -- e1 - e2 - e3 -- null (getNextEdge(), getPreviousEdge())
*
* And end with this (insert new vertex v5 before v1) -
*
* v5 v1 v2 v3 v4 (edge->getPrev(), edge->getNext())
* \ / \ / \ / \ /
* null -- e4 - e1 - e2 - e3 -- null (getNextEdge(), getPreviousEdge())
*
* OR!
*
* You must take those provisions into account as well, as each requires
* different steps. The steps are outlined below, but they are all a
* derivation of the above steps.
*
* Yeah, I had to figure that out all on paper.
*
* Let's do this beeyatch!
*
* @param Falcraft\Data\Types\Node\VertexInterface &$vertex The new vertex to insert
* @param mixed $identifier The identifier (v3 for instance) to insert after
*
* @return bool If the operation was successful
*
*/
public function insertBefore(TypesResource\VertexInterface &$vertex, $identifier)
{
// Get the first edge
$currentEdge = $this->getFirstEdge();
if ($currentEdge->getNextEdge() == null && ($currentEdge->getNext() == null || $currentEdge->getPrevious() == null)) {
/* currentEdge is the first, the last, the alpha and the omega
* AND one of its vertices is null
*
* ? ?
* \ /
* CE
*/
if ($currentEdge->getPrevious() == null) {
/* null ?
* \ /
* CE
*/
// we're empty bro
return false;
} else {
if ($currentEdge->getNext() == null && $currentEdge->getPrevious()->getIdentifier() == $identifier) {
/* *v1* null
* \ /
* CE
*/
$currentEdge->setNext($currentEdge->getPrevious());
$currentEdge->setPrevious($vertex);
/* NV *v1*
* \ /
* CE
*/
return true;
} else {
/* Only prev set and it's not the target, next code will
access next which is NOT set damn you, please return
your ticket */
return false;
}
}
}
// Else currentEdge is the first edge, and is full
if ($currentEdge->getPrevious()->getIdentifier() == $identifier) {
/* v5 v1 v2 v3 v4 (edge->getPrev(), edge->getNext())
* \ / \ / \ / \ /
* null -- e4 - e1 - e2 - e3 -- null (getNextEdge(), getPreviousEdge())
*/
// Make e4 linking to v5 (new) and v1 (old)
$newEdge = new OrderedEdge($vertex, $currentEdge->getPrevious());
// link e4 <- e1 done
$currentEdge->setPreviousEdge($newEdge);
$newEdge->setNextEdge($currentEdge);
// IMPORTANT! Add edge to collection of edges
$this->edges->add($newEdge);
return true;
}
// Look through the rest of the vertices for a match
while ($currentEdge && $currentEdge->getNext()->getIdentifier() != $identifier) {
$currentEdge =& $currentEdge->getNextEdge();
}
if ($currentEdge == null) {
/* We exhausted the list, with no match
Return, a disappointment to your mother */
return false;
}
if ($currentEdge->getPreviousEdge() == null) {
/* We're still at the beginning of the list so we're going to start with this:
*
* v1 *v2* v3
* \ / \ /
* null -- (e1) - e2 - ...
*
* And end with this:
*
* v1 v4 *v2* v3
* \ / \ / \ /
* null -- (e1) - e3 - e2 -- null
*
* new edge e3 = nv, e1's next
* e1 next = nv
* e1 nextEdge = e3
* e2 prevEdge = e3
* e3 nextedge = e2
* e3 prevedge = e1
*/
$newEdge = new OrderedEdge($vertex, $currentEdge->getNext());
$currentEdge->setNext($vertex);
//$nextEdge->setPreviousEdge($currentEdge);
$newEdge->setPreviousEdge($currentEdge);
//$nextEdge->setNextEdge($currentEdge->getNextEdge());
if ($e = $currentEdge->getNextEdge()) {
$newEdge->setNextEdge($e->getNextEdge());
$e->getNextEdge()->setPreviousEdge($newEdge);
}
$currentEdge->setNextEdge($newEdge);
} else {
/* Otherwise we have this:
*
* ? *v* (v4)
* \ /
* ? - CE - ? ()
*
* v1 v2 v3 v5 v4 (edge->getPrev(), edge->getNext())
* \ / \ / \ / \ /
* null -- e1 - e2 - e4 - (e3) -- null (getNextEdge(), getPreviousEdge())
*
* new edge e4 - e3's prev, nv
* e3 prev = nv
* e2 nextEdge = e4
* e3 prevEdge = e4
*/
// Create e4 with v3 (e3->prev) as prev, new vertex on next
$newEdge = new OrderedEdge($currentEdge->getPrevious(), $vertex);
$currentEdge->setPrevious($vertex);
$newEdge->setPreviousEdge($currentEdge->getPreviousEdge());
$newEdge->setNextEdge($currentEdge);
$currentEdge->getPreviousEdge()->setNextEdge($newEdge);
$currentEdge->setPreviousEdge($newEdge);
}
// IMPORTANT! Add edge to collection of edges
$this->edges->add($newEdge);
return true;
}
/**
* Utility function to connect to edges together in a given list
*
* @static
*
* @param Falcraft\Data\Types\Resource\OrderedEdge &$left The left object
* @param Falcraft\Data\Types\Resource\OrderedEdge &$right The right object
*
*/
public static function connect(OrderedEdge &$left, OrderedEdge &$right)
{
$left->setNextEdge($right);
$right->setPreviousEdge($left);
}
