code: public int getFixedDataOffset(FieldType type)
     {
        int result;
        FieldItem item = m_map.get(type);
        if (item != null)
        {
           result = item.getFixedDataOffset();
        }
        else
        {
           result = -1;
        }
        return result;
     }
docs: Retrieve the fixed data offset for a specific field.
  
  @param type field type
  @return offset