CrcToolMain.java

package com.linkedin.databus.core.util;
/*
 *
 * Copyright 2013 LinkedIn Corp. All rights reserved
 *
 * 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.
 *
*/


import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.Charset;

public class CrcToolMain
{
  private static final int BUFFER_SIZE = 4096;

  private static void printCrc(ByteOrder order, byte[] value)
  {
    ByteBuffer argBuffer = ByteBuffer.wrap(value).order(order);
    long crc = ByteBufferCRC32.getChecksum(argBuffer);
    ByteBuffer resBuffer = ByteBuffer.allocate(4).order(order);
    Utils.putUnsignedInt(resBuffer, 0, crc);

    System.out.print(order.toString() + ": 0x");
    for (int i = 0; i < 4; ++i) System.out.print(Integer.toHexString(resBuffer.get(i) & 0xFF));
  }

  private static void printBothCrcs(String label, byte[] value)
  {
    System.out.print(label + ": ");
    printCrc(ByteOrder.LITTLE_ENDIAN, value);
    System.out.print("     ");
    printCrc(ByteOrder.BIG_ENDIAN, value);
    System.out.println();
  }

  /**
   * @param args
   */
  public static void main(String[] args) throws IOException
  {
    for (String arg: args)
    {
      printBothCrcs(arg, arg.getBytes(Charset.defaultCharset()));
    }

    if (System.in.available() > 0)
    {
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      byte[] buffer = new byte[BUFFER_SIZE];

      int bytesRead;
      while ((bytesRead = System.in.read(buffer)) > 0)
      {
        baos.write(buffer, 0, bytesRead);
      }
      baos.close();

      byte[] inBytes = baos.toByteArray();
      printBothCrcs("<stdin>", inBytes);
    }
  }

}