private function precalculate()
{
$an = Normalizer::fromString($this->a);
$bn = Normalizer::fromString($this->b);
$al = $an->getLines(true);
$bl = $bn->getLines(true);
$slm = new SequenceMatcher($al, $bl, 0.7);
$lops = $slm->getOpCodes(true);
$ops = [];
foreach ($lops as $lop) {
$atn = Normalizer::fromArray($lop[5]);
$btn = Normalizer::fromArray($lop[6]);
$at = $atn->getTokens();
$bt = $btn->getTokens();
$swm = new SequenceMatcher($at, $bt, 0.9);
$wops = $swm->getOpCodes(true);
$op = $lop;
$op['wops'] = $wops;
$ops[] = $op;
}
$this->ops = $ops;
foreach ($this->ops as $o => $lop) {
foreach ($lop['wops'] as $wop) {
list($wtag, $as, $al, $bs, $bl, $at, $bt) = $wop;
switch ($wop[0]) {
case 'delete':
$this->removals += count($at);
break;
case 'insert':
$this->additions += count($bt);
break;
case 'replace':
$this->removals += count($at);
$this->additions += count($bt);
break;
}
}
}
}
