com.facebook.hive.orc.lazy.LazyBinaryTreeReader.java Source code

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Here is the source code for com.facebook.hive.orc.lazy.LazyBinaryTreeReader.java

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//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.facebook.hive.orc.lazy;

import java.io.EOFException;
import java.io.IOException;
import java.util.List;
import java.util.Map;

import org.apache.hadoop.io.BytesWritable;

import com.facebook.hive.orc.InStream;
import com.facebook.hive.orc.OrcProto;
import com.facebook.hive.orc.RunLengthIntegerReader;
import com.facebook.hive.orc.StreamName;
import com.facebook.hive.orc.WriterImpl;
import com.facebook.hive.orc.OrcProto.RowIndex;
import com.facebook.hive.orc.OrcProto.RowIndexEntry;

public class LazyBinaryTreeReader extends LazyTreeReader {

    private InStream stream;
    private RunLengthIntegerReader lengths;

    public LazyBinaryTreeReader(int columnId, long rowIndexStride) {
        super(columnId, rowIndexStride);
    }

    @Override
    public void startStripe(Map<StreamName, InStream> streams, List<OrcProto.ColumnEncoding> encodings,
            RowIndex[] indexes, long rowBaseInStripe) throws IOException {
        super.startStripe(streams, encodings, indexes, rowBaseInStripe);
        StreamName name = new StreamName(columnId, OrcProto.Stream.Kind.DATA);
        stream = streams.get(name);
        lengths = new RunLengthIntegerReader(streams.get(new StreamName(columnId, OrcProto.Stream.Kind.LENGTH)),
                false, WriterImpl.INT_BYTE_SIZE);
        if (indexes[columnId] != null) {
            loadIndeces(indexes[columnId].getEntryList(), 0);
        }
    }

    @Override
    public void seek(int index) throws IOException {
        stream.seek(index);
        lengths.seek(index);
    }

    @Override
    public int loadIndeces(List<RowIndexEntry> rowIndexEntries, int startIndex) {
        int updatedStartIndex = super.loadIndeces(rowIndexEntries, startIndex);
        updatedStartIndex = stream.loadIndeces(rowIndexEntries, updatedStartIndex);
        return lengths.loadIndeces(rowIndexEntries, updatedStartIndex);
    }

    @Override
    public Object next(Object previous) throws IOException {
        BytesWritable result = null;
        if (valuePresent) {
            if (previous == null) {
                result = new BytesWritable();
            } else {
                result = (BytesWritable) previous;
            }
            int len = (int) lengths.next();
            result.setSize(len);
            int offset = 0;
            while (len > 0) {
                int written = stream.read(result.getBytes(), offset, len);
                if (written < 0) {
                    throw new EOFException("Can't finish byte read from " + stream);
                }
                len -= written;
                offset += written;
            }
        }
        return result;
    }

    @Override
    public void skipRows(long numNonNullValues) throws IOException {
        long lengthToSkip = 0;
        for (int i = 0; i < numNonNullValues; ++i) {
            lengthToSkip += lengths.next();
        }
        stream.skip(lengthToSkip);
    }

    @Override
    public void close() throws IOException {
        super.close();
        if (stream != null) {
            stream.close();
        }
        if (lengths != null) {
            lengths.close();
        }
    }

}