org.hedera.util.SeekableInputStream.java Source code

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Here is the source code for org.hedera.util.SeekableInputStream.java

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/**
 * Copyright 2011 Yusuke Matsubara
 *
 * Licensed 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 org.hedera.util;

import java.io.FilterInputStream;
import java.io.IOException;

import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.Seekable;
import org.apache.hadoop.io.compress.CodecPool;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionCodecFactory;
import org.apache.hadoop.io.compress.CompressionInputStream;
import org.apache.hadoop.io.compress.Decompressor;
import org.apache.hadoop.io.compress.SplitCompressionInputStream;
import org.apache.hadoop.io.compress.SplittableCompressionCodec;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;

public class SeekableInputStream extends FilterInputStream implements Seekable {
    private final Seekable seek;
    private final SplitCompressionInputStream sin;

    public SeekableInputStream(FSDataInputStream in) {
        super(in);
        this.seek = in;
        this.sin = null;
    }

    public SeekableInputStream(SplitCompressionInputStream cin) {
        super(cin);
        this.seek = cin;
        this.sin = cin;
    }

    public SeekableInputStream(CompressionInputStream cin, FSDataInputStream in) {
        super(cin);
        this.seek = in;
        this.sin = null;
    }

    public static SeekableInputStream getInstance(Path path, long start, long end, FileSystem fs,
            CompressionCodecFactory compressionCodecs) throws IOException {
        CompressionCodec codec = compressionCodecs.getCodec(path);
        FSDataInputStream din = fs.open(path);
        if (codec != null) {
            Decompressor decompressor = CodecPool.getDecompressor(codec);
            if (codec instanceof SplittableCompressionCodec) {
                SplittableCompressionCodec scodec = (SplittableCompressionCodec) codec;
                SplitCompressionInputStream cin = scodec.createInputStream(din, decompressor, start, end,
                        SplittableCompressionCodec.READ_MODE.BYBLOCK);
                return new SeekableInputStream(cin);
            } else {
                // non-splittable compression input stream
                // no seeking or offsetting is needed
                assert start == 0;
                CompressionInputStream cin = codec.createInputStream(din, decompressor);
                return new SeekableInputStream(cin, din);
            }
        } else {
            // non compression input stream
            // we seek to the start of the split
            din.seek(start);
            return new SeekableInputStream(din);
        }
    }

    public static SeekableInputStream getInstance(FileSplit split, FileSystem fs,
            CompressionCodecFactory compressionCodecs) throws IOException {
        return getInstance(split.getPath(), split.getStart(), split.getStart() + split.getLength(), fs,
                compressionCodecs);
    }

    public SplitCompressionInputStream getSplitCompressionInputStream() {
        return this.sin;
    }

    @Override
    public long getPos() throws IOException {
        return this.seek.getPos();
    }

    @Override
    public void seek(long pos) throws IOException {
        this.seek.seek(pos);
    }

    @Override
    public boolean seekToNewSource(long targetPos) throws IOException {
        return this.seek.seekToNewSource(targetPos);
    }

    @Override
    public String toString() {
        return this.in.toString();
    }
}