private function gen_nick_color($nick)
    {
        if (isset($this->nick_colors[$nick]))
        { 
            return $this->nick_colors[$nick];
        }
        $md5 = sha1(strtolower($nick));
        $r = hexdec(substr($md5, 0, 2));
        $g = hexdec(substr($md5, 6, 2));
        $b = hexdec(substr($md5, 12, 2));
                
        if ($r < 0x60) $r += 0x60;
        if ($g < 0x60) $g += 0x60;
        if ($b < 0x60) $b += 0x60;
        
        $n = hexdec(substr($md5, 10, 1));
        if ($n <= 5)
        {
            $r = min(255, $r * 2);
        }
        else if ($n >= 6 && $n <= 10)
        {
            $g = min(255, $g * 2);
        }
        else if ($n >= 11)
        {
            $b = min(255, $b * 2);
        }
        $c = array(floor($r), floor($g), floor($b));
        $this->nick_colors[$nick] = $c;
        return $c;
    }