code: private void readNextPage() throws IOException {
          processNextPage();
          while (currentPageType != PAGE_META_TYPE_1 && currentPageType != PAGE_META_TYPE_2
                  && currentPageType != PAGE_MIX_TYPE && currentPageType != PAGE_DATA_TYPE) {
              if (eof) {
                  return;
              }
              processNextPage();
          }
      }
docs: The method to read next page from sas7bdat file and put it into {@link SasFileParser#cachedPage}. If this page
  has {@link SasFileConstants#PAGE_META_TYPE_1} or {@link SasFileConstants#PAGE_META_TYPE_2} type method process
  it's subheaders. Method skips page with type other than {@link SasFileConstants#PAGE_META_TYPE_1},
  {@link SasFileConstants#PAGE_META_TYPE_2}, {@link SasFileConstants#PAGE_MIX_TYPE} or
  {@link SasFileConstants#PAGE_DATA_TYPE} and reads next.
  
  @throws IOException if reading from the {@link SasFileParser#sasFileStream} stream is impossible.