/**
* Scan TSV file and return the keys, offsets and lengths of each line
*
* @param string $tsv
* @param int[] $sortPositions
* @param TsvSerializerInterface $serializer
* @return array
*/
private function index($tsv, $sortPositions, $serializer)
{
$keys = array();
$offsets = array();
$lengths = array();
$resource = $this->fopen($tsv, "r");
$offset = $this->ftell($resource);
while (($line = $serializer->fgets($resource)) !== FALSE) {
if ($line == "\n") {
continue;
}
$values = $serializer->unserialize($line);
$keys[] = $this->constructKey($values, $sortPositions);
$offsets[] = $offset;
$lengths[] = ($newOffset = $this->ftell($resource)) - $offset;
$offset = $newOffset;
}
$this->close($resource);
return array($keys, $offsets, $lengths);
}
private function tupleFromLine($line)
{
return $this->serializer->unserialize($line);
}
