org.apache.hadoop.fs.MD5MD5CRC32FileChecksum.java Source code

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Here is the source code for org.apache.hadoop.fs.MD5MD5CRC32FileChecksum.java

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/**
 * 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 org.apache.hadoop.fs;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.Options.ChecksumOpt;
import org.apache.hadoop.io.MD5Hash;
import org.apache.hadoop.io.WritableUtils;
import org.apache.hadoop.util.DataChecksum;

/** MD5 of MD5 of CRC32. */
@InterfaceAudience.LimitedPrivate({ "HDFS" })
@InterfaceStability.Unstable
public class MD5MD5CRC32FileChecksum extends FileChecksum {
    public static final int LENGTH = MD5Hash.MD5_LEN + (Integer.SIZE + Long.SIZE) / Byte.SIZE;

    private int bytesPerCRC;
    private long crcPerBlock;
    private MD5Hash md5;

    /** Same as this(0, 0, null) */
    public MD5MD5CRC32FileChecksum() {
        this(0, 0, null);
    }

    /** Create a MD5FileChecksum */
    public MD5MD5CRC32FileChecksum(int bytesPerCRC, long crcPerBlock, MD5Hash md5) {
        this.bytesPerCRC = bytesPerCRC;
        this.crcPerBlock = crcPerBlock;
        this.md5 = md5;
    }

    @Override
    public String getAlgorithmName() {
        return "MD5-of-" + crcPerBlock + "MD5-of-" + bytesPerCRC + getCrcType().name();
    }

    public static DataChecksum.Type getCrcTypeFromAlgorithmName(String algorithm) throws IOException {
        if (algorithm.endsWith(DataChecksum.Type.CRC32.name())) {
            return DataChecksum.Type.CRC32;
        } else if (algorithm.endsWith(DataChecksum.Type.CRC32C.name())) {
            return DataChecksum.Type.CRC32C;
        }

        throw new IOException("Unknown checksum type in " + algorithm);
    }

    @Override
    public int getLength() {
        return LENGTH;
    }

    @Override
    public byte[] getBytes() {
        return WritableUtils.toByteArray(this);
    }

    /** returns the CRC type */
    public DataChecksum.Type getCrcType() {
        // default to the one that is understood by all releases.
        return DataChecksum.Type.CRC32;
    }

    @Override
    public ChecksumOpt getChecksumOpt() {
        return new ChecksumOpt(getCrcType(), bytesPerCRC);
    }

    @Override
    public void readFields(DataInput in) throws IOException {
        bytesPerCRC = in.readInt();
        crcPerBlock = in.readLong();
        md5 = MD5Hash.read(in);
    }

    @Override
    public void write(DataOutput out) throws IOException {
        out.writeInt(bytesPerCRC);
        out.writeLong(crcPerBlock);
        md5.write(out);
    }

    @Override
    public String toString() {
        return getAlgorithmName() + ":" + md5;
    }
}