/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.index.translog;
import org.apache.lucene.store.BufferedChecksum;
import org.elasticsearch.common.io.stream.FilterStreamInput;
import org.elasticsearch.common.io.stream.StreamInput;
import java.io.EOFException;
import java.io.IOException;
import java.util.zip.CRC32;
import java.util.zip.Checksum;
/**
* Similar to Lucene's BufferedChecksumIndexInput, however this wraps a
* {@link StreamInput} so anything read will update the checksum
*/
public final class BufferedChecksumStreamInput extends FilterStreamInput {
private static final int SKIP_BUFFER_SIZE = 1024;
private byte[] skipBuffer;
private final Checksum digest;
public BufferedChecksumStreamInput(StreamInput in) {
super(in);
this.digest = new BufferedChecksum(new CRC32());
}
public BufferedChecksumStreamInput(StreamInput in, BufferedChecksumStreamInput reuse) {
super(in);
if (reuse == null ) {
this.digest = new BufferedChecksum(new CRC32());
} else {
this.digest = reuse.digest;
digest.reset();
this.skipBuffer = reuse.skipBuffer;
}
}
public long getChecksum() {
return this.digest.getValue();
}
@Override
public byte readByte() throws IOException {
final byte b = delegate.readByte();
digest.update(b);
return b;
}
@Override
public void readBytes(byte[] b, int offset, int len) throws IOException {
delegate.readBytes(b, offset, len);
digest.update(b, offset, len);
}
@Override
public void reset() throws IOException {
delegate.reset();
digest.reset();
}
@Override
public int read() throws IOException {
return readByte() & 0xFF;
}
@Override
public boolean markSupported() {
return delegate.markSupported();
}
@Override
public long skip(long numBytes) throws IOException {
if (numBytes < 0) {
throw new IllegalArgumentException("numBytes must be >= 0, got " + numBytes);
}
if (skipBuffer == null) {
skipBuffer = new byte[SKIP_BUFFER_SIZE];
}
assert skipBuffer.length == SKIP_BUFFER_SIZE;
long skipped = 0;
for (; skipped < numBytes; ) {
final int step = (int) Math.min(SKIP_BUFFER_SIZE, numBytes - skipped);
readBytes(skipBuffer, 0, step);
skipped += step;
}
return skipped;
}
@Override
public synchronized void mark(int readlimit) {
delegate.mark(readlimit);
}
public void resetDigest() {
digest.reset();
}
}