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<?php |
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namespace Hexogen\KDTree; |
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class FileTreePersister implements TreePersisterInterface |
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{ |
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/** |
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* @var string path to the file |
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*/ |
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private $path; |
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/** |
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* @var resource file handler |
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*/ |
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private $handler; |
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/** |
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* @var int |
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*/ |
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private $dimensions; |
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/** |
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* @var int |
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*/ |
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private $nodeMemorySize; |
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public function __construct(string $path) |
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{ |
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$this->path = $path; |
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} |
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/** |
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* @param KDTreeInterface $tree |
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* @param string $identifier that identifies persisted tree(may be a filename, database name etc.) |
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* @return mixed |
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*/ |
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public function convert(KDTreeInterface $tree, string $identifier) |
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{ |
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$dataChunk = null; |
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$this->handler = fopen($this->path . '/' . $identifier, 'wb'); |
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$this->dimensions = $tree->getDimensionCount(); |
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$this->nodeMemorySize = $this->dimensions * 8 + 3 * 4; |
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$dataChunk = pack('V', $this->dimensions); |
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fwrite($this->handler, $dataChunk); |
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$itemCount = $tree->getItemCount(); |
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$dataChunk = pack('V', $itemCount); |
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fwrite($this->handler, $dataChunk); |
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$upperBound = $tree->getMaxBoundary(); |
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$this->writeCoordinate($upperBound); |
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$lowerBound = $tree->getMinBoundary(); |
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$this->writeCoordinate($lowerBound); |
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$this->writeNode($tree->getRoot()); |
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fclose($this->handler); |
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} |
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/** |
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* @param NodeInterface $node |
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*/ |
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private function writeNode(NodeInterface $node) |
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{ |
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$position = ftell($this->handler); |
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$coordinate = []; |
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$item = $node->getItem(); |
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$itemId = $item->getId(); |
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$dataChunk = pack('V', $itemId); |
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fwrite($this->handler, $dataChunk); |
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$dataChunk = pack('V', 0); // left position currently unknown so it equal 0/null |
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fwrite($this->handler, $dataChunk); |
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$rightNode = $node->getRight(); |
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$rightPosition = 0; |
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if ($rightNode) { |
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$rightPosition = $position + $this->nodeMemorySize; |
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} |
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$dataChunk = pack('V', $rightPosition); |
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fwrite($this->handler, $dataChunk); |
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for ($i = 0; $i < $this->dimensions; $i++) { |
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$coordinate[] = $item->getNthDimension($i); |
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} |
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$this->writeCoordinate($coordinate); |
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if ($rightNode) { |
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$this->writeNode($rightNode); |
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} |
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$leftNode = $node->getLeft(); |
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if ($leftNode == null) { |
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return; |
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} |
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$leftPosition = ftell($this->handler); |
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fseek($this->handler, $position + 4); |
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$dataChunk = pack('V', $leftPosition); |
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fwrite($this->handler, $dataChunk); |
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fseek($this->handler, $leftPosition); |
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$this->writeNode($leftNode); |
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} |
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/** |
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* @param array $coordinate |
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*/ |
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private function writeCoordinate(array $coordinate) |
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{ |
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$dataChunk = pack('d'.$this->dimensions, ...$coordinate); |
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fwrite($this->handler, $dataChunk); |
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} |
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} |
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hexogen /
kdtree
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVarassignment in line 1 and the$higherassignment in line 2 are dead. The first because$myVaris never used and the second because$higheris always overwritten for every possible time line.