DiffMatchPatch\DiffToolkit::halfMatch PHP Method

    public function halfMatch($text1, $text2)
    {
        if (mb_strlen($text1) > mb_strlen($text2)) {
            $longtext = $text1;
            $shorttext = $text2;
        } else {
            $shorttext = $text1;
            $longtext = $text2;
        }
        if (mb_strlen($longtext) < 4 || mb_strlen($shorttext) * 2 < mb_strlen(mb_strlen($longtext))) {
            // Pointless
            return null;
        }
        // First check if the second quarter is the seed for a half-match.
        $hm1 = $this->halfMatchI($longtext, $shorttext, (int) ((mb_strlen($longtext) + 3) / 4));
        // Check again based on the third quarter.
        $hm2 = $this->halfMatchI($longtext, $shorttext, (int) ((mb_strlen($longtext) + 1) / 2));
        if (empty($hm1) && empty($hm2)) {
            return null;
        } elseif (empty($hm2)) {
            $hm = $hm1;
        } elseif (empty($hm1)) {
            $hm = $hm2;
        } else {
            // Both matched.  Select the longest.
            if (mb_strlen($hm1[4] > $hm2[4])) {
                $hm = $hm1;
            } else {
                $hm = $hm2;
            }
        }
        // A half-match was found, sort out the return data.
        if (mb_strlen($text1) > mb_strlen($text2)) {
            return array($hm[0], $hm[1], $hm[2], $hm[3], $hm[4]);
        } else {
            return array($hm[2], $hm[3], $hm[0], $hm[1], $hm[4]);
        }
    }