//add recognized cookie field: expires/domain/path/secure/httponly/version, into cookie
    public bool addFieldToCookie(ref Cookie ck, pairItem pairInfo)
    {
        bool added = false;
        if (pairInfo.key != "")
        {
            string lowerKey = pairInfo.key.ToLower();
            switch (lowerKey)
            {
                case "expires":
                    DateTime expireDatetime;
                    if (DateTime.TryParse(pairInfo.value, out expireDatetime))
                    {
                        // note: here coverted to local time: GMT +8
                        ck.Expires = expireDatetime;

                        //update expired filed
                        if (DateTime.Now.Ticks > ck.Expires.Ticks)
                        {
                            ck.Expired = true;
                        }

                        added = true;
                    }
                    break;
                case "domain":
                    ck.Domain = pairInfo.value;
                    added = true;
                    break;
                case "secure":
                    ck.Secure = true;
                    added = true;
                    break;
                case "path":
                    ck.Path = pairInfo.value;
                    added = true;
                    break;
                case "httponly":
                    ck.HttpOnly = true;
                    added = true;
                    break;
                case "version":
                    int versionValue;
                    if (int.TryParse(pairInfo.value, out versionValue))
                    {
                        ck.Version = versionValue;
                        added = true;
                    }
                    break;
                default:
                    break;
            }
        }

        return added;
    }//addFieldToCookie

    

    public bool parseSingleCookie(string cookieStr, ref Cookie ck)
    {
        bool parsedOk = true;
        //Cookie ck = new Cookie();
        //string[] expressions = cookieStr.Split(";".ToCharArray(),StringSplitOptions.RemoveEmptyEntries);
        //refer: http://msdn.microsoft.com/en-us/library/b873y76a.aspx
        string[] expressions = cookieStr.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
        //get cookie name and value
        pairItem pair = new pairItem();
        if (parseCookieNameValue(expressions[0], out pair))
        {
            ck.Name = pair.key;
            ck.Value = pair.value;

            string[] fieldExpressions = getSubStrArr(expressions, 1, expressions.Length - 1);
            foreach (string eachExpression in fieldExpressions)
            {
                //parse key and value
                if (parseCookieField(eachExpression, out pair))
                {
                    // add to cookie field if possible
                    addFieldToCookie(ref ck, pair);
                }