Subversion Repositories bacoAlunos

/*

 * BytesUtils.java

 *

 * Created on 2 de Dezembro de 2002, 0:24

 */

package jomm.utils;

import java.io.*;

import java.math.BigInteger;

import java.rmi.dgc.VMID;

import java.security.*;

import java.util.Random;

import org.apache.log4j.Logger;

/**

 *

 * @author  Jorge Machado

 */

public class BytesUtils {

    private static int counter = 0;

    private static 1.5.0/docs/api/java/util/Random.html">Random random = new 1.5.0/docs/api/java/util/Random.html">Random();

    private static 1.5.0/docs/api/java/rmi/dgc/VMID.html">VMID vmid = new 1.5.0/docs/api/java/rmi/dgc/VMID.html">VMID();

    private static 1.5.0/docs/api/java/util/logging/Logger.html">Logger logger = 1.5.0/docs/api/java/util/logging/Logger.html">Logger.getLogger(BytesUtils.class);

    /** Private Constructor */

    private BytesUtils () {}

         public static 1.5.0/docs/api/java/lang/String.html">String getMd5FromFile(1.5.0/docs/api/java/lang/String.html">String filepath)

         {

                        return getMD5(getBytes(filepath));

         }

     public static byte[] getBytes(1.5.0/docs/api/java/lang/String.html">String fileName)

    {

        byte[] data = null;

        try{

            1.5.0/docs/api/java/io/FileInputStream.html">FileInputStream r = new 1.5.0/docs/api/java/io/FileInputStream.html">FileInputStream(fileName);

            1.5.0/docs/api/java/io/File.html">File f = new 1.5.0/docs/api/java/io/File.html">File(fileName);

            //this value is never bigger than a integer

            int len =(int) f.length();

            data = new byte[len];

            int bytesRead = 0;

            bytesRead = r.read(data);

            r.close();

            if(bytesRead == -1)

                return null;

        }

        catch(1.5.0/docs/api/java/io/FileNotFoundException.html">FileNotFoundException e)

        {

            logger.error("Files getBytes()",e);

            return null;

        }

        catch(1.5.0/docs/api/java/io/IOException.html">IOException e)

        {

            logger.error("Files getData()",e);

            return null;

        }

        return data;

    }

    public static 1.5.0/docs/api/java/lang/String.html">String getMD5(1.5.0/docs/api/java/lang/String.html">String data)

    {

        return getMD5(data.getBytes());

    }

    public static 1.5.0/docs/api/java/lang/String.html">String getMD5(byte[] data)

    {

        return toHex(getMD5Bytes(data));

    }

    public static 1.5.0/docs/api/java/lang/String.html">String getDigestMD5Hex(1.5.0/docs/api/java/lang/String.html">String str){

        byte[] digest = getDigestMD5(str.getBytes());

        if(digest != null)

            return toHex(digest);

        return null;

    }

    public static byte[] getDigestMD5(byte[] data)

    {

        byte[] result = null;

        try{

            1.5.0/docs/api/java/security/MessageDigest.html">MessageDigest md5 = 1.5.0/docs/api/java/security/MessageDigest.html">MessageDigest.getInstance("MD5");

            md5.update(data);

            result = md5.digest();            

        }

        catch(1.5.0/docs/api/java/security/NoSuchAlgorithmException.html">NoSuchAlgorithmException e)

        {

            //this never hapens beacause MD5 is a correct algoritm

             logger.fatal("MD5 function does not exists",e);

        }

        return result;

    }

    /*********************************************************

     *Returns true if the two digests are equal

     *

     *******************************************************/

    public static boolean isDigestEqual(byte[] b1,byte[] b2)

    {

        try{

            1.5.0/docs/api/java/security/MessageDigest.html">MessageDigest md5 = 1.5.0/docs/api/java/security/MessageDigest.html">MessageDigest.getInstance("MD5");

            return md5.isEqual(b1,b2);

        }

        catch(1.5.0/docs/api/java/security/NoSuchAlgorithmException.html">NoSuchAlgorithmException e)

        {

            //this never hapens beacause MD5 is a correct algoritm

             logger.fatal("MD5 function does not exists",e);

        }

        return false;

    }

    public static byte[] getMD5Bytes(byte[] data)

    {

        try

        {

            1.5.0/docs/api/java/security/MessageDigest.html">MessageDigest digest = 1.5.0/docs/api/java/security/MessageDigest.html">MessageDigest.getInstance("MD5");

            return digest.digest(data);

        }

        catch (1.5.0/docs/api/java/security/NoSuchAlgorithmException.html">NoSuchAlgorithmException e)

        {

            logger.fatal("MD5 function does not exists",e);

        }

        return null;

    }

    /**

     * Return a hex representation of the byte array

     *

     * @param data The data to transform.

     * @return A hex representation of the data.

     */

    public static 1.5.0/docs/api/java/lang/String.html">String toHex(byte[] data)

    {

        if ((data == null) || (data.length == 0))

            return null;

        1.5.0/docs/api/java/lang/StringBuffer.html">StringBuffer result = new 1.5.0/docs/api/java/lang/StringBuffer.html">StringBuffer();

        // This is far from the most efficient way to do things...

        for (int i = 0; i < data.length; i++)

        {

            int low =  (int) (data[i] & 0x0F);

            int high = (int) (data[i] & 0xF0);

            result.append(1.5.0/docs/api/java/lang/Integer.html">Integer.toHexString(high).substring(0, 1));

            result.append(1.5.0/docs/api/java/lang/Integer.html">Integer.toHexString(low));

        }

        return result.toString();

    }

    /**

     * Generate a unique key.

     * The key is a long (length 38 to 40) sequence of digits.

     *

     * @return A unique key as a long sequence of base-10 digits.

     */

    public static 1.5.0/docs/api/java/lang/String.html">String generateKey()

    {

        return new 1.5.0/docs/api/java/math/BigInteger.html">BigInteger(generateBytesKey()).abs().toString();

    }

    /**

     * Generate a unique key.

     * The key is a 32-character long sequence of hex digits.

     *

     * @return A unique key as a long sequence of hex digits.

     */

    public static 1.5.0/docs/api/java/lang/String.html">String generateHexKey()

    {

        return toHex(generateBytesKey());

    }

    /**

     * Generate a unique key as a byte array.

     *

     * @return A unique key as a byte array.

     */

    public static synchronized byte[] generateBytesKey()

    {

        byte[] junk = new byte[16];

        random.nextBytes(junk);

        1.5.0/docs/api/java/lang/String.html">String input = new 1.5.0/docs/api/java/lang/StringBuffer.html">StringBuffer().append(vmid).append(new java.util.5+0%2Fdocs%2Fapi+Date">Date()).append(junk).append(counter++).toString();

        return getMD5Bytes(input.getBytes());

    }

    // The following two methods are taken from the Jakarta IOUtil class.

    /**

     * Copy stream-data from source to destination. This method does not

     * buffer, flush or close the streams, as to do so would require making

     * non-portable assumptions about the streams' origin and further use. If

     * you wish to perform a buffered copy, use {@link #bufferedCopy}.

     *

     * @param input The InputStream to obtain data from.

     * @param output The OutputStream to copy data to.

     */

    public static void copy( final 5+0%2Fdocs%2Fapi+InputStream">InputStream input, final 5+0%2Fdocs%2Fapi+OutputStream">OutputStream output )

        throws 1.5.0/docs/api/java/io/IOException.html">IOException

    {

        final int BUFFER_SIZE = 1024 * 4;

        final byte[] buffer = new byte[ BUFFER_SIZE ];

        while( true )

        {

            final int count = input.read( buffer, 0, BUFFER_SIZE );

            if( -1 == count ) break;

            // write out those same bytes

            output.write( buffer, 0, count );

        }

        //needed to flush cache

        //output.flush();

    }

    public static void bufferedCopy( final 5+0%2Fdocs%2Fapi+InputStream">InputStream source, final 5+0%2Fdocs%2Fapi+OutputStream">OutputStream destination )

        throws 1.5.0/docs/api/java/io/IOException.html">IOException

    {

        final 1.5.0/docs/api/java/io/BufferedInputStream.html">BufferedInputStream input = new 1.5.0/docs/api/java/io/BufferedInputStream.html">BufferedInputStream( source );

        final 1.5.0/docs/api/java/io/BufferedOutputStream.html">BufferedOutputStream output = new 1.5.0/docs/api/java/io/BufferedOutputStream.html">BufferedOutputStream( destination );

        copy( input, output );

        output.flush();

    }

}