Class RecordReaderUtils

java/core/src/java/org/apache/orc/impl/RecordReaderUtils.java:50–860

Stateless methods shared between RecordReaderImpl and EncodedReaderImpl.

 * Stateless methods shared between RecordReaderImpl and EncodedReaderImpl.
 */
public class RecordReaderUtils {
  /**
   * The maximum size of array to allocate, value being the same as {@link java.util.Hashtable}
   */
  public static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;

  private static final HadoopShims SHIMS = HadoopShimsFactory.get();
  private static final boolean supportVectoredIO =
      SHIMS.supportVectoredIO(VersionInfo.getVersion());
  private static final Logger LOG = LoggerFactory.getLogger(RecordReaderUtils.class);

  private static class DefaultDataReader implements DataReader {
    private FSDataInputStream file;
    private ByteBufferAllocatorPool pool;
    private HadoopShims.ZeroCopyReaderShim zcr = null;
    private final Supplier<FileSystem> fileSystemSupplier;
    private final Path path;
    private final boolean useZeroCopy;
    private final int minSeekSize;
    private final double minSeekSizeTolerance;
    private InStream.StreamOptions options;
    private boolean isOpen = false;

    private DefaultDataReader(DataReaderProperties properties) {
      this.fileSystemSupplier = properties.getFileSystemSupplier();
      this.path = properties.getPath();
      this.file = properties.getFile();
      this.useZeroCopy = properties.getZeroCopy();
      this.options = properties.getCompression();
      this.minSeekSize = properties.getMinSeekSize();
      this.minSeekSizeTolerance = properties.getMinSeekSizeTolerance();
    }

    @Override
    public void open() throws IOException {
      if (file == null) {
        this.file = fileSystemSupplier.get().open(path);
      }
      if (useZeroCopy) {
        // ZCR only uses codec for boolean checks.
        pool = new ByteBufferAllocatorPool();
        zcr = RecordReaderUtils.createZeroCopyShim(file, options.getCodec(), pool);
      } else {
        zcr = null;
      }
      isOpen = true;
    }

    @Override
    public OrcProto.StripeFooter readStripeFooter(StripeInformation stripe) throws IOException {
      if (!isOpen) {
        open();
      }
      long offset = stripe.getOffset() + stripe.getIndexLength() + stripe.getDataLength();
      int tailLength = (int) stripe.getFooterLength();

      // read the footer
      ByteBuffer tailBuf = ByteBuffer.allocate(tailLength);