phpseclib\Crypt\RC2::_encryptBlock PHP Method

    function _encryptBlock($in)
    {
        list($r0, $r1, $r2, $r3) = array_values(unpack('v*', $in));
        $keys = $this->keys;
        $limit = 20;
        $actions = array($limit => 44, 44 => 64);
        $j = 0;
        for (;;) {
            // Mixing round.
            $r0 = ($r0 + $keys[$j++] + (($r1 ^ $r2) & $r3 ^ $r1) & 0xffff) << 1;
            $r0 |= $r0 >> 16;
            $r1 = ($r1 + $keys[$j++] + (($r2 ^ $r3) & $r0 ^ $r2) & 0xffff) << 2;
            $r1 |= $r1 >> 16;
            $r2 = ($r2 + $keys[$j++] + (($r3 ^ $r0) & $r1 ^ $r3) & 0xffff) << 3;
            $r2 |= $r2 >> 16;
            $r3 = ($r3 + $keys[$j++] + (($r0 ^ $r1) & $r2 ^ $r0) & 0xffff) << 5;
            $r3 |= $r3 >> 16;
            if ($j === $limit) {
                if ($limit === 64) {
                    break;
                }
                // Mashing round.
                $r0 += $keys[$r3 & 0x3f];
                $r1 += $keys[$r0 & 0x3f];
                $r2 += $keys[$r1 & 0x3f];
                $r3 += $keys[$r2 & 0x3f];
                $limit = $actions[$limit];
            }
        }
        return pack('vvvv', $r0, $r1, $r2, $r3);
    }