CSKernelClient.cUtil.getInfoString C# (CSharp) Method

        public static String getInfoString(String source, String key, String defaultValue)
        {

            if (String.IsNullOrEmpty(source)) {
                return defaultValue;
            }

            key = "#"+ key;

            int i = source.ToLower().IndexOf(key.ToLower(), 0);

            // the key can't apears more than one
            //
            if (source.ToLower().IndexOf(key.ToLower(), i + 1) != -1) 
            { 
                throw(new Exception("cUtil.getInfoString: the key can't apears more than one.")); 
            }

            // if the key is not present return default
            //
            if (i == -1) 
            {
              return defaultValue;
            } 
            else 
            {
              const string c_errorstr = "cUtil.getInfoString: source invalid, the character {0} is not present.";

              int j = source.ToLower().IndexOf(";".ToLower(), i);
              if (j == -1) 
              { 
                  throw(new Exception(String.Format(c_errorstr, ";"))); 
              }

              int k = source.Substring(i, j-i).ToLower().IndexOf("=".ToLower(), 0);
              if (k == -1) 
              { 
                  throw(new Exception(String.Format(c_errorstr, "="))); 
              }
              k = k + i;
              return source.Substring(k + 1, j - k - 1);
            }
        }