/**
*
* @param string $a
* @param string $b
* @param float $divisor for calculating the minimum required percentage of overlap
* @return string a copy of $a, where the overlap is indicated with <overlap></overlap>
* tags
*/
public static function overlap($a, $b, $divisor = 3.0)
{
self::$divisor = $divisor;
if ($a == $b) {
return $a;
} elseif (empty($a)) {
return '';
} elseif (empty($b)) {
return $a;
}
$lcs = StringDiff::longest_common_substring($a, $b);
if (empty($lcs)) {
return $a;
}
$atripartite = StringDiff::tripartite($a, $lcs);
$btripartite = StringDiff::tripartite($b, $lcs);
$headdiff = StringDiff::overlap($atripartite[0], $btripartite[0]);
$taildiff = StringDiff::overlap($atripartite[2], $btripartite[2]);
return $headdiff . '<overlap>' . $lcs . '</overlap>' . $taildiff;
}
