code: private void processColumns()
     {
        int fieldID = MPPUtility.getInt(m_data, m_headerOffset);
        m_headerOffset += 4;
  
        m_dataOffset = MPPUtility.getInt(m_data, m_headerOffset);
        m_headerOffset += 4;
  
        FieldType type = FieldTypeHelper.getInstance(fieldID);
        if (type.getDataType() != null)
        {
           processKnownType(type);
        }
     }
docs: Processes graphical indicator definitions for each column.