content: /*
   * 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.celeborn.common;
  
  import java.util.Objects;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.zip.CRC32;
  
  public class CelebornCRC32 {
  
    private final AtomicInteger current;
  
    CelebornCRC32(int i) {
      this.current = new AtomicInteger(i);
    }
  
    CelebornCRC32() {
      this(0);
    }
  
    static int compute(byte[] bytes) {
      CRC32 hashFunction = new CRC32();
      hashFunction.update(bytes);
      return (int) hashFunction.getValue();
    }
  
    static int compute(byte[] bytes, int offset, int length) {
      CRC32 hashFunction = new CRC32();
      hashFunction.update(bytes, offset, length);
      return (int) hashFunction.getValue();
    }
  
    static int combine(int first, int second) {
      first =
          (((byte) second + (byte) first) & 0xFF)
              | ((((byte) (second >> 8) + (byte) (first >> 8)) & 0xFF) << 8)
              | ((((byte) (second >> 16) + (byte) (first >> 16)) & 0xFF) << 16)
              | (((byte) (second >> 24) + (byte) (first >> 24)) << 24);
      return first;
    }
  
    public void addChecksum(int checksum) {
      while (true) {
        int val = current.get();
        int newVal = combine(checksum, val);
        if (current.compareAndSet(val, newVal)) {
          break;
        }
      }
    }
  
    void addData(byte[] bytes, int offset, int length) {
      addChecksum(compute(bytes, offset, length));
    }
  
    int get() {
      return current.get();
    }
  
    @Override
    public String toString() {
      return "CelebornCRC32{" + "current=" + current + '}';
    }
  
    @Override
    public boolean equals(Object o) {
      if (o == null || getClass() != o.getClass()) return false;
      CelebornCRC32 that = (CelebornCRC32) o;
      return current.get() == that.current.get();
    }
  
    @Override
    public int hashCode() {
      return Objects.hashCode(current);
    }
  }
  