// -----------------------------------------------------------------------------
// ChecksumAdler32.java
// -----------------------------------------------------------------------------

/*
 * =============================================================================
 * Copyright (c) 1998-2011 Jeffrey M. Hunter. All rights reserved.
 * 
 * All source code and material located at the Internet address of
 * http://www.idevelopment.info is the copyright of Jeffrey M. Hunter and
 * is protected under copyright laws of the United States. This source code may
 * not be hosted on any other site without my express, prior, written
 * permission. Application to host any of the material elsewhere can be made by
 * contacting me at jhunter@idevelopment.info.
 *
 * I have made every effort and taken great care in making sure that the source
 * code and other content included on my web site is technically accurate, but I
 * disclaim any and all responsibility for any loss, damage or destruction of
 * data or any other property which may arise from relying on it. I will in no
 * case be liable for any monetary damages arising from such loss, damage or
 * destruction.
 * 
 * As with any code, ensure to test this code in a development environment 
 * before attempting to run it in production.
 * =============================================================================
 */
 
import java.util.zip.CheckedInputStream;
import java.util.zip.Adler32;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

/**
 * -----------------------------------------------------------------------------
 * Used to provide an example of how to calculate the checksum of a file using
 * the Adler-32 checksum engine.
 * 
 * @version 1.0
 * @author  Jeffrey M. Hunter  (jhunter@idevelopment.info)
 * @author  http://www.idevelopment.info
 * -----------------------------------------------------------------------------
 */

public class ChecksumAdler32 {

    private static void doChecksum(String fileName) {

        try {

            CheckedInputStream cis = null;
            long fileSize = 0;
            try {
                // Computer Adler-32 checksum
                cis = new CheckedInputStream(
                        new FileInputStream(fileName), new Adler32());

                fileSize = new File(fileName).length();
                
            } catch (FileNotFoundException e) {
                System.err.println("File not found.");
                System.exit(1);
            }

            byte[] buf = new byte[128];
            while(cis.read(buf) >= 0) {
            }

            long checksum = cis.getChecksum().getValue();
            System.out.println(checksum + " " + fileSize + " " + fileName);

        } catch (IOException e) {
            e.printStackTrace();
            System.exit(1);
        }


    }


    /**
     * Sole entry point to the class and application.
     * @param args Array of String arguments.
     */
    public static void main(String[] args) {

        if (args.length != 1) {
            System.err.println("Usage: java ChecksumAdler32 filename");
        } else {
            doChecksum(args[0]);
        }

    }

}