io.datarouter.filesystem.snapshot.compress.ChecksumBlockCompressor Maven / Gradle / Ivy
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/*
* Copyright © 2009 HotPads ([email protected])
*
* 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 io.datarouter.filesystem.snapshot.compress;
import java.util.Arrays;
import java.util.zip.CRC32;
import io.datarouter.bytes.codec.longcodec.RawLongCodec;
import io.datarouter.filesystem.snapshot.encode.EncodedBlock;
public class ChecksumBlockCompressor implements BlockCompressor{
public static final String NAME = "checksum";
private static final RawLongCodec RAW_LONG_CODEC = RawLongCodec.INSTANCE;
@Override
public String name(){
return NAME;
}
@Override
public CompressedBlock compress(EncodedBlock encodedBlock, boolean concatChunks){
var crc = new CRC32();
byte[][] chunksAndChecksum = new byte[encodedBlock.chunks.length + 1][];
for(int i = 0; i < encodedBlock.chunks.length; ++i){
crc.update(encodedBlock.chunks[i]);
chunksAndChecksum[i] = encodedBlock.chunks[i];
}
byte[] checksum = RAW_LONG_CODEC.encode(crc.getValue());
chunksAndChecksum[encodedBlock.chunks.length] = checksum;
return new CompressedBlock(chunksAndChecksum);
}
@Override
public byte[] decompress(byte[] withChecksum, boolean validateChecksum){
byte[] withoutChecksum = Arrays.copyOfRange(withChecksum, 0, withChecksum.length - 8);
if(validateChecksum){
var crc = new CRC32();
crc.update(withoutChecksum);
long expectedChecksum = RAW_LONG_CODEC.decode(withChecksum, withChecksum.length - 8);
long actualChecksum = crc.getValue();
if(expectedChecksum != actualChecksum){
String message = String.format("invalid checksum, expected=%s, actual=%s",
expectedChecksum,
actualChecksum);
throw new IllegalStateException(message);
}
}
return withoutChecksum;
}
}