public function process(Vertex $vertex, Digraph $graph)
{
if ($graph->inDegreeOf($vertex) === 0 && !$vertex instanceof Vertex\Function_) {
Helper::remove($vertex, $graph);
return true;
}
return false;
}
public function countUsages(Variable $var, Digraph $graph)
{
$counter = 0;
foreach ($graph->vertices() as $vtx) {
if (in_array($var, $vtx->getVariables(), true)) {
$counter++;
}
}
return $counter;
}
/**
* Convert a Graph to a phpDocumentor graph, usable for printing
*
* @param \Gliph\Graph\Digraph $graph The graph to print
*
* @return \phpDocumentor\GraphViz\Graph The copied graph
*/
protected function convertGraph(Digraph $graph)
{
$new = Graph::create("dump");
$nodes = new \SplObjectStorage();
$ctr = 0;
foreach ($graph->vertices() as $vertex) {
$nodes[$vertex] = Node::create('node_' . $ctr++, (string) $vertex);
$new->setNode($nodes[$vertex]);
}
foreach ($graph->edges() as $edge) {
$new->link(Edge::create($nodes[$edge[0]], $nodes[$edge[1]]));
}
return $new;
}
public function process(Vertex $vertex, Digraph $graph)
{
if ($vertex instanceof Vertex\Phi) {
$types = [];
foreach ($vertex->getValues() as $value) {
$types[] = (string) $value->getType();
}
$types = array_unique($types);
if ($vertex->getResult()->getType()->isUnknown()) {
$type = null;
$setAll = false;
if (count($types) === 1 && $types[0] !== 'unknown') {
$type = Type::normalizeType($types[0]);
} elseif (count($types) === 2 && in_array('long', $types) && in_array('numeric', $types)) {
$type = new Type(Type::TYPE_LONG);
$setAll = true;
} elseif (count($types) === 2 && in_array('double', $types) && in_array('numeric', $types)) {
$type = new Type(Type::TYPE_DOUBLE);
$setAll = true;
} elseif (count($types) === 2 && in_array('bool', $types) && in_array('numeric', $types)) {
$type = new Type(Type::TYPE_BOOLEAN);
}
if ($type) {
$vertex->getResult()->setType($type);
if ($setAll) {
foreach ($vertex->getValues() as $value) {
$value->setType($type);
}
}
return true;
}
}
if (count($vertex->getValues()) === 1) {
// remove phi node
list($val) = iterator_to_array($vertex->getValues());
$result = $vertex->getResult();
foreach ($graph->vertices() as $vtx) {
$vtx->replaceVariable($result, $val);
if ($vtx instanceof Assignment && $vtx->getResult() === $result) {
$vtx->setResult($val);
}
}
Helper::remove($vertex, $graph);
return true;
}
}
return false;
}
/**
* Finds connected components in the provided directed graph.
*
* @param Digraph $graph
* The Digraph to search for connected components.
* @param TarjanSCCVisitor $visitor
* The visitor that will collect and store the connected components. One
* will be created if not provided.
*
* @return TarjanSCCVisitor
* The finalized visitor.
*/
public static function tarjan_scc(Digraph $graph, TarjanSCCVisitor $visitor = NULL)
{
$visitor = $visitor ?: new TarjanSCCVisitor();
$counter = 0;
$stack = array();
$indices = new \SplObjectStorage();
$lowlimits = new \SplObjectStorage();
$visit = function ($vertex) use(&$visit, &$counter, $graph, &$stack, $indices, $lowlimits, $visitor) {
$indices->attach($vertex, $counter);
$lowlimits->attach($vertex, $counter);
$stack[] = $vertex;
$counter++;
foreach ($graph->successorsOf($vertex) as $head) {
if (!$indices->contains($head)) {
$visit($head);
$lowlimits[$vertex] = min($lowlimits[$vertex], $lowlimits[$head]);
} else {
if (in_array($head, $stack, TRUE)) {
$lowlimits[$vertex] = min($lowlimits[$vertex], $indices[$head]);
}
}
}
if ($lowlimits[$vertex] === $indices[$vertex]) {
$visitor->newComponent();
do {
$other = array_pop($stack);
$visitor->addToCurrentComponent($other);
} while ($other != $vertex);
}
};
foreach ($graph->vertices() as $v) {
if (!$indices->contains($v)) {
$visit($v);
}
}
return $visitor;
}
public static function isLiveVar(Variable $var, Vertex $vtx, Digraph $graph)
{
static $seen = [];
if (in_array($vtx, $seen, true)) {
return false;
} elseif (in_array($var, $vtx->getVariables(), true)) {
return true;
}
$seen[] = $vtx;
foreach ($graph->successorsOf($vtx) as $sub) {
if (self::isLiveVar($var, $sub, $graph)) {
array_pop($seen);
return true;
}
}
array_pop($seen);
return false;
}
/**
* Finds source vertices in a Digraph, then enqueues them.
*
* @param Digraph $graph
* @param DepthFirstVisitorInterface $visitor
*
* @return \SplQueue
*/
public static function find_sources(Digraph $graph, DepthFirstVisitorInterface $visitor)
{
$incomings = new \SplObjectStorage();
$queue = new \SplQueue();
foreach ($graph->edges() as $edge) {
if (!isset($incomings[$edge[1]])) {
$incomings[$edge[1]] = new \SplObjectStorage();
}
$incomings[$edge[1]]->attach($edge[0]);
}
// Prime the queue with vertices that have no incoming edges.
foreach ($graph->vertices() as $vertex) {
if (!$incomings->contains($vertex)) {
$queue->push($vertex);
$visitor->onInitializeVertex($vertex, TRUE, $queue);
} else {
$visitor->onInitializeVertex($vertex, FALSE, $queue);
}
}
return $queue;
}
