/**
 * 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.trevni;

import java.nio.ByteBuffer;
import java.util.zip.CRC32;

/** Implements CRC32 checksum. */
final class Crc32Checksum extends Checksum {
  private CRC32 crc32 = new CRC32();

  @Override public int size() { return 4; }

  @Override public ByteBuffer compute(ByteBuffer data) {
    crc32.reset();
    crc32.update(data.array(), data.position(), data.remaining());

    ByteBuffer result = ByteBuffer.allocate(size());
    result.putInt((int)crc32.getValue());
    result.flip();
    return result;
 }

}

Add crc32 checksum, checkum tests and a bugfix.