/**
 * $Id: $
 * $Date: $
 *
 */

package org.xmlsh.util.commands;
import org.xmlsh.util.Base64Coder;
import java.math.BigInteger;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.xmlsh.core.CoreException;



/**
 * @author David A. Lee
 */
public class Checksum
{
  public enum Format {
    HEX,
    BINARY,
    BASE64
  };
	private		byte[]	mMD5;
	private		long	mLength;

	private Checksum( byte[] md5 , long len )
	{
		mMD5 = md5;
		mLength = len ;
	}

	public static String toHexString(byte[] bytes)
	{

		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < bytes.length; i++)
		{
			int b = bytes[i] & 0xFF;

			String hex = Integer.toString(b, 16);
			if (hex.length() < 2)
				sb.append('0');
			sb.append(hex);

		}
		return sb.toString();

	}

	private static MessageDigest getMD5Digest() throws NoSuchAlgorithmException
	{
		MessageDigest digest = MessageDigest.getInstance("MD5");
		return digest;

	}

	public static Checksum calcChecksum(InputStream in) throws CoreException, IOException  
	{
		return calcChecksum( in , null );

	}
	/**
	 * @param file
	 * @return
	 * @throws CoreException 
	 * @throws IOException 
	 */
	public static Checksum calcChecksum(InputStream in, OutputStream out) throws CoreException, IOException  
	{
		long totlen = 0;
		try
		{
			final int kBUF_SIZE = 1024 * 4;
			MessageDigest digest = getMD5Digest();
			if (digest == null)
				return null;

			byte buf[] = new byte[kBUF_SIZE];
			int len;
			while ((len = in.read(buf)) > 0){
				digest.update(buf, 0, len);
				totlen += len ;
				if( out != null )
					out.write(buf , 0 , len );
			}

			return new Checksum(digest.digest() , totlen );
		}
		catch (NoSuchAlgorithmException e)
		{
			throw new CoreException("Exception getting MD5 algorithm");
		}

	}

	/**
	 * @param file
	 * @return
	 */
	public static Checksum calcChecksum(File file) throws CoreException, IOException
	{
		InputStream in = new FileInputStream(file);
		Checksum checksum = calcChecksum(in);
		in.close();
		return checksum;

	}
	/**
	 * @param file
	 * @return
	 */
	public static Checksum calcChecksum(String data) throws CoreException, IOException
	{
		return calcChecksum( data.getBytes());

	}

	/**
	 * @param file
	 * @return
	 */
	public static Checksum calcChecksum(byte[] data ) throws CoreException, IOException
	{
		InputStream in = new ByteArrayInputStream(data);
		Checksum checksum = calcChecksum(in);
		in.close();
		return checksum;

	}

	/**
	 * @return the mD5
	 */
	public String getMD5(Format format) {
            switch( format )
            {
             case BINARY :
                return new BigInteger(mMD5).toString();
            case BASE64:
               return new String( Base64Coder.encode( mMD5 , mMD5.length ) );
            case HEX :
            default:
		return toHexString(mMD5);
            }
	}

	/**
	 * @return the length
	 */
	public long getLength() {
		return mLength;
	}


}




//
//
//Copyright (C) 2008-2014 David A. Lee.
//
//The contents of this file are subject to the "Simplified BSD License" (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.opensource.org/licenses/bsd-license.php 
//
//Software distributed under the License is distributed on an "AS IS" basis,
//WITHOUT WARRANTY OF ANY KIND, either express or implied.
//See the License for the specific language governing rights and limitations under the License.
//
//The Original Code is: all this file.
//
//The Initial Developer of the Original Code is David A. Lee
//
//Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
//Contributor(s): none.
//