PROJECT DIVA CUSTOM DLC SLOT CHANGER v0.15

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;

/* This program is free software. It comes without any warranty, to
 * the extent permitted by applicable law. You can redistribute it
 * and/or modify it under the terms of the Do What The Fuck You Want
 * To Public License, Version 2, as published by Sam Hocevar. See
 * http://sam.zoy.org/wtfpl/COPYING for more details. */

public class SlotChanger {

    /**
     * @param args
     */
    public static void main(String[] args) {
        System.out.println("### PROJECT DIVA CUSTOM DLC SLOT CHANGER v0.15");
        System.out.println("Written by Suyo (ProjectDIVA.net)");
        System.out.println("----------------------------------------");

        FileInputStream fis;
        String ifilen = "in.EDAT";
        if (args[0] != null) ifilen = args[0];
        String ofilen = "out.EDAT";
        File ifile = new File(ifilen);
        File ofile = new File(ofilen);

        if (!ifile.exists() || !ifile.isFile()) {
            System.out.println(ifilen+": does not exist!");
            return;
        }
        if (ofile.exists()) {
            System.out.println(ofilen+": exists already! Please rename it before running this!");
            return;
        }

        int[] fileArray;
        try {
            System.out.println("Opening "+ifilen+"...");
            fis = new FileInputStream(ifile);
            fileArray = new int[(int) ifile.length()];

            int i=0;
            int offs=0;

            System.out.println("Reading file... this could take a while.");
            while(i != -1) { /* -1 is a constant for 'EOF' : end of file. */
                i=fis.read();
                if (i!=-1) fileArray[offs] = i;
                offs++;
            }
            fis.close();
        } catch (Exception e) {
            System.out.println(ifilen+": Unknown error while opening!");
            return;
        }

        System.out.println("\nDLC Type: "+((char) fileArray[0x1800]));
        System.out.println("Current Slot: "+((char) fileArray[0x1803])+((char) fileArray[0x1804])+((char) fileArray[0x1805]));

        System.out.print("Enter new Slot (0-999): ");
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String newslot = null;
        try {
            newslot = br.readLine();
        } catch (IOException ioe) {
            System.out.println("IO error trying to read new slot!");
            return;
        }

        try {
            int i = Integer.parseInt(newslot);
            if (i>999) {
                System.out.println("The number is too big!");
                return;
            } else if (i<0) {
                System.out.println("The number is too small!");
                return;
            }
        } catch(NumberFormatException nfe) {
            System.out.println("This isn't a number!");
            return;
        }

        while (newslot.length()<3) newslot = "0" + newslot;
        fileArray[0x1803] = newslot.charAt(0);
        fileArray[0x1804] = newslot.charAt(1);
        fileArray[0x1805] = newslot.charAt(2);

        try {
            System.out.println("\nOpening "+ofilen+"...");
            FileOutputStream fos = new FileOutputStream(ofile);
            DataOutputStream dos = new DataOutputStream(fos);
            System.out.println("Writing file... this could take a while.");
            for (int i: fileArray) {
                dos.writeByte(i);
            }
            dos.close();
        } catch (Exception e) {
            System.out.println(ofilen+": Unknown Error while writing!");
        }

        System.out.println("\nSuccess! We're done here.");
    }
}