public static function buildTree($s)
{
$t = new Tree();
$seenSymbols = array();
$pq = new PriorityQueue();
// Add leaf nodes for each symbol to the priority queue.
for ($i = 0; $i < strlen($s); ++$i) {
$c = $s[$i];
if (array_key_exists($c, $seenSymbols)) {
continue;
}
$occurrences = 0;
for ($j = $i; $j < strlen($s); ++$j) {
if ($s[$j] != $c) {
continue;
}
$occurrences++;
}
$node = new Node($c, $occurrences);
$pq->enqueue($node);
$t->leaves[$c] = $node;
$seenSymbols[$c] = true;
}
if ($pq->size() == 0) {
return $t;
}
// While there is more than one node left in the priority queue:
while ($pq->size() > 1) {
// Remove the two nodes of highest priority (lowest probability).
$node1 = $pq->dequeue();
$node2 = $pq->dequeue();
// Create a new internal node with the two nodes as children with
// p_total = p_1 + p_2
$newNode = new Node(null, $node1->weight + $node2->weight);
$newNode->left = $node1;
$newNode->right = $node2;
$node1->parent = $newNode;
$node2->parent = $newNode;
// Add the new node to the queue.
$pq->enqueue($newNode);
}
// The final node in the priority queue is the root.
$t->root = $pq->dequeue();
return $t;
}
unset($in_progress[$k]);
}
}
$md5top = md5($top);
$text = curl_multi_getcontent($ch);
Error::disableLogging();
db_query("REPLACE INTO primitive_cache (url, content) VALUES ('%s', '%s')", $md5top, $text);
Error::enableLogging();
db_end_transaction('primitive_cache', $md5top);
curl_multi_remove_handle($mch, $ch);
curl_close($ch);
$n_reqs_procd++;
fputs($fp, "Daemon {$GLOBALS['client']} processed {$top}\r\n");
Error::generate('debug', "Processed {$top}");
} else {
if (count($in_progress) < $max_simult_queries && $curl_stack->size() > 0) {
$ch = $curl_stack->pop();
$top = $completed->pop();
$md5top = md5($top);
db_query("INSERT IGNORE INTO primitive_cache_lock (id,locked) VALUES ('%s','0')", $md5top);
$exists = db_affected_rows() == 0;
// TODO: CURLOPT_TIMEVALUE and CURLOPT_TIMECONDITION on cache timestamp for Last-Modified if exists
if (!$exists) {
$locked = db_start_transaction('primitive_cache', $md5top, $blocking);
} else {
$locked = false;
}
if ($locked) {
// we've got a lock, we can either start or finish
$in_progress[] = array('ch' => $ch, 'top' => $top);
curl_multi_add_handle($mch, $ch);