/**
* Calculate Halstead metrics
*
* @param $filename
* @return Result
*/
public function calculate($filename)
{
$this->inventory($filename);
$result = new Result();
$uniqueOperators = array_map('unserialize', array_unique(array_map('serialize', $this->operators)));
$uniqueOperands = array_map('unserialize', array_unique(array_map('serialize', $this->operands)));
$n1 = sizeof($uniqueOperators, COUNT_NORMAL);
$n2 = sizeof($uniqueOperands, COUNT_NORMAL);
$N1 = sizeof($this->operators, COUNT_NORMAL);
$N2 = sizeof($this->operands, COUNT_NORMAL);
if ($n2 == 0 || $N2 == 0 || $n2 == 2) {
// files without operators
$V = $n1 = $n2 = $N1 = $N2 = $E = $D = $B = $T = $I = $L = 0;
} else {
$devAbility = 3000;
$N = $N1 + $N2;
$n = $n1 + $n2;
$V = $N * log($n, 2);
$L = 2 / max(1, $n1) * ($n2 / $N2);
$D = $n1 / 2 * ($N2 / $n2);
$E = $V * $D;
$B = $V / $devAbility;
$T = $E / 18;
$I = $L * $V;
}
$result->setLength($N1 + $N2)->setVocabulary($n1 + $n2)->setVolume(round($V, 2))->setDifficulty(round($D, 2))->setEffort(round($E, 2))->setLevel(round($L, 2))->setBugs(round($B, 2))->setTime(round($T))->setIntelligentContent(round($I, 2))->setNumberOfOperators($N1)->setNumberOfOperands($N2)->setNumberOfUniqueOperators($n1)->setNumberOfUniqueOperands($n2);
return $result;
}
