public int readIntField(int fileId,
                          int fieldOffsetInRow) throws IOException {
    long offsetInFile = toOffsetInFile(fileId) + fieldOffsetInRow;
    int offsetInPage = storage.toOffsetInPage(offsetInFile);

    Page page = storage.pageByOffset(offsetInFile);
    ByteBuffer rawPageBuffer = page.rawPageBuffer();

    return (int)INT_HANDLE.getVolatile(rawPageBuffer, offsetInPage);
  }
public int readIntField(int fileId,
                          int fieldOffsetInRow)