function diff_local($from_lines, $to_lines)
{
global $wgExternalDiffEngine;
wfProfileIn(__METHOD__);
if ($wgExternalDiffEngine == 'wikidiff3') {
// wikidiff3
$wikidiff3 = new WikiDiff3();
$wikidiff3->diff($from_lines, $to_lines);
$this->xchanged = $wikidiff3->removed;
$this->ychanged = $wikidiff3->added;
unset($wikidiff3);
} else {
// old diff
$n_from = sizeof($from_lines);
$n_to = sizeof($to_lines);
$this->xchanged = $this->ychanged = array();
$this->xv = $this->yv = array();
$this->xind = $this->yind = array();
unset($this->seq);
unset($this->in_seq);
unset($this->lcs);
// Skip leading common lines.
for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
if ($from_lines[$skip] !== $to_lines[$skip]) {
break;
}
$this->xchanged[$skip] = $this->ychanged[$skip] = false;
}
// Skip trailing common lines.
$xi = $n_from;
$yi = $n_to;
for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
if ($from_lines[$xi] !== $to_lines[$yi]) {
break;
}
$this->xchanged[$xi] = $this->ychanged[$yi] = false;
}
// Ignore lines which do not exist in both files.
for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
$xhash[$this->_line_hash($from_lines[$xi])] = 1;
}
for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
$line = $to_lines[$yi];
if ($this->ychanged[$yi] = empty($xhash[$this->_line_hash($line)])) {
continue;
}
$yhash[$this->_line_hash($line)] = 1;
$this->yv[] = $line;
$this->yind[] = $yi;
}
for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
$line = $from_lines[$xi];
if ($this->xchanged[$xi] = empty($yhash[$this->_line_hash($line)])) {
continue;
}
$this->xv[] = $line;
$this->xind[] = $xi;
}
// Find the LCS.
$this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
}
wfProfileOut(__METHOD__);
}
public function getResult(AncestorComparator $other)
{
$diffengine = new WikiDiff3(10000, 1.35);
$differences = $diffengine->diff_range($other->ancestorsText, $this->ancestorsText);
if (count($differences) == 0) {
return null;
}
$changeTxt = new ChangeTextGenerator($this, $other);
return $changeTxt->getChanged($differences)->toString();
}
