Untitled

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.security.NoSuchAlgorithmException;
import java.util.Scanner;
import java.security.SecureRandom;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Calendar;
import java.util.Date;
import java.nio.charset.StandardCharsets;
import java.io.FileNotFoundException;
import java.security.SecureRandom;

public class Main extends JFrame
{
    int i = 0;
    boolean logged_in = false;

    public static void main(String[] args)
    {
        new Main().setVisible(true);
    }

    public class User
    {
        String salt;
        String username;
        String password;
    }

    public Main()
    {
        super("Login");

        setLayout(new GridBagLayout());

        GridBagConstraints gbc = new GridBagConstraints();

        //username label/field
        JLabel userlabel = new JLabel("Enter Username:");
        gbc.gridx = 0;
        gbc.gridy = 1;
        add(userlabel,gbc);

        final JTextField userfield = new JTextField(20);
        gbc.gridx = 1;
        gbc.gridy = 1;
        add(userfield,gbc);
        //end username label/field

        //password label/field
        JLabel passlabel = new JLabel("Enter Password:");
        gbc.gridx = 0;
        gbc.gridy = 2;
        add(passlabel,gbc);

        final JPasswordField passfield = new JPasswordField(20);
        passfield.setEchoChar('*');
        gbc.gridx = 1;
        gbc.gridy = 2;
        add(passfield,gbc);
        //end password label/field

        //user array
        User[] userArray = new User[100];
        System.out.print(i);
        //end user array

        //login button
        JButton login = new JButton("Login");
        gbc.gridx = 1;
        gbc.gridy = 3;
        add(login,gbc);

        //register button
        JButton register = new JButton("Register");
        gbc.gridx = 2;
        gbc.gridy = 3;
        add(register,gbc);

        //logout button
        JButton logout = new JButton("Logout");

        //end buttons

        logout.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e3) {
                    setVisible(true);
                }
            });

        login.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e1)
                {

                    int lineNum = 0;
                    if(lineNum <100){
                        System.out.print("lineNum =" + lineNum+ "\n");
                        while((((userArray[lineNum]).username).equals(userfield.getText())))
                        {   System.out.print("lineNum = " + lineNum+ "\n");
                            System.out.print("\nfound username");

                            System.out.print("\nuser salt is not null");
                            System.out.print("\nuser salt = " + userArray[lineNum].salt);
                            String hex2 = Hash.mainHash(String.valueOf(passfield), userArray[lineNum].salt);
                            System.out.print("\nproposed hash = " + hex2);
                            if(userArray[lineNum].password.equals(hex2))
                            {
                                logged_in = true;

                                JFrame frame2 = new JFrame("Members");
                                frame2.setVisible(true);
                                frame2.setSize(500, 500);

                                JLabel welcome = new JLabel("Welcome " + userfield.getText() + "!");

                                JLabel newline = new JLabel("<html> <br/> </html>");

                                DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
                                Date date = new Date();
                                JLabel datelabel = new JLabel("Your local time  is: \t" + (dateFormat.format(date)));

                                setVisible(false);

                                JPanel panel = new JPanel();
                                frame2.add(panel);
                                panel.add(welcome);
                                panel.add(datelabel);
                                panel.add(logout);
                                lineNum = 0;
                            }else {lineNum++;}
                        }

                    }
                }
            });

        register.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e2)
                {
                    SecureRandom secureRNG = new SecureRandom();
                    int secureSalt = secureRNG.nextInt(1000);

                    String salt = Integer.toString(secureSalt);

                    String hex = Hash.mainHash(String.valueOf(passfield), salt);
                    userArray[i] = new User();

                    userArray[i].username = userfield.getText();
                    userArray[i].password = hex;
                    userArray[i].salt = salt;

                    try {
                        //String saltedpass = hex;
                        String pass = String.valueOf(passfield.getPassword());

                        if(pass.length() >= 5)
                        {
                            BufferedWriter writer = new BufferedWriter(new FileWriter("C:/Users/cm6140/Desktop/test.txt", true));

                            writer.newLine();
                            writer.write(userArray[i].username);
                            writer.write(" ");
                            writer.write(userArray[i].password);
                            writer.write(" ");
                            //writer.write(pass);
                            writer.write(" ");
                            writer.write(userArray[i].salt);
                            writer.close();

                            JFrame frame2 = new JFrame("Members");
                            frame2.setVisible(true);
                            frame2.setSize(500, 500);
                            JLabel welcome = new JLabel("Welcome " + userfield.getText() + "!");

                            JLabel newline = new JLabel("<html> <br/> </html>");

                            DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
                            Date date = new Date();
                            JLabel datelabel = new JLabel("Your local time is: \t" + (dateFormat.format(date)));

                            setVisible(false);

                            JPanel panel = new JPanel();
                            frame2.add(panel);
                            panel.add(welcome);
                            panel.add(datelabel);
                            panel.add(logout);
                        }

                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    i++;
                }
            });

        setSize(500,500);
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }

    public static class Hash
    {
        private static final long MASK_16_BITS = 0xFFFFL;
        private static final int MASK_BIT_1 = 0x1;

        /*
         * Paul Hsieh's Hash Function.
         *
         * @param data data to hash
         * @param dataLength length of the data, in bytes
         * @param hashedValue previous value of the hash. If it is the start of the
         * method, used the length of the data (ex.: 8 bytes).
         * @return
         */

        public static int superFastHash(long data, int hash)
        {
            int tmp;
            //int rem;

            //if (len <= 0) {
            //   return 0;
            //}

            //rem = len & 3;
            //len >>= 2;

            //Main Loop
            for (int i = 0; i < 4; i += 2) {
                // Get lower 16 bits
                hash += get16BitsAligned(data, i);
                // Calculate some random value with second-lower 16 bits
                tmp = (get16BitsAligned(data, i + 1) << 11) ^ hash;
                hash = (hash << 16) ^ tmp;
                // At this point, it would advance the data, but since it is restricted
                // to longs (64-bit values), it is unnecessary).
                hash += hash >> 11;
            }

            // Handle end cases //
            // There are no end cases, main loop is done in chuncks of 32 bits.

            // Force "avalanching" of final 127 bits //
            hash ^= hash << 3;
            hash += hash >> 5;
            hash ^= hash << 4;
            hash += hash >> 17;
            hash ^= hash << 25;
            hash += hash >> 6;
            //System.out.print(hash);
            return hash;
        }

        /*
         * Returns 16 bits from the long number.
         *
         * @param data
         * @param offset one of 0 to 3
         * @return
         */

        public static int get16BitsAligned(long data, int offset)
        {
            // Normalize offset
            offset = offset%4;
            //System.out.println("offset:"+offset);
            // Align the mask
            long mask = MASK_16_BITS << 16*offset;
            //System.out.println("Mask:"+Long.toHexString(mask));
            //System.out.println("Data:"+Long.toHexString(data));

            // Get the bits
            long result = data & mask;

            // Put bits in position
            return (int) (result >>> (16*offset));
        }

        public static String mainHash(String password, String salt)
        {
            String password2 = password + salt;

            int dechash;
            byte[] bytes = password2.getBytes(StandardCharsets.US_ASCII);
            long result = 0;
            for (int i = 0; i < bytes.length; i++) {
                result <<= 8;
                result |= (bytes[i] & 0xFF);
            }
            dechash = superFastHash(result, password2.length());
            StringBuilder sb = new StringBuilder();
            sb.append(Integer.toHexString(dechash));
            if (sb.length() % 2 > 0) {
                sb.insert(0, '0'); // pad with leading zero if needed
            }
            String hex = sb.toString();
            return hex;
        }
    }
}