Save and Load Code Tutorial

Man, I wrote this thing so long ago, I can hardly believe it exists. Anyways, I dug it up from the ashes, gave it a quick grammar and understandability (is that a word?) edit, and put it up here.


I attached a map, it's a little different then the code I put here (think of this code as concept, the map actually gets the job done - rather sloppily I might add). I explained why it was different on a post on the second page.




(What is it? A save and load code tutorial, you know, the things that you can save heroes across games with)






The actual tutorial:




Most things from the tutorial were lost because of a terrible forum disaster :P This is all that I could recover, because I had to format my computer a while ago.


Please post feedback (on the thread)! It takes time to write this! Lots of time!

What is a save/load password system, anyway? If you haven’t played an RPG where they have one, then you probably don’t know, but then again, why are you here? It’s a complex series of numbers and letters that you can save a hero from an RPG with. Most codes save the level of the hero, some items, and maybe some gold.


Part 1: Setting up the trigger.

Most games will have you type in a command like "-save" or something similar to save your hero, so we need to have an event reading in the command:


And that’s all you need for the event part of the password system. Not hard? Good.

Part 2: Setting up the variables.

Oh no!! Variables! Actually, I don’t understand why everyone thinks variables are so confusing. It’s just a way of holding some data. I could write a tutorial about variables... except I'm already writing this tutorial...

Anyway what we need is different strings to hold different parts of the password. So lets make a array variable called PasswordParts. I'm gonna make this variable because I want to store separate parts of the password. For example, I'll store gold in one part, wood in another, experience in a third, and so on. (An array, very simply put, is like many variables combined together, all that can be accessed by a number – you might wanna read about it somewhere else though) So, assuming your still in the trigger window, do the following:

1. Hit ctrl+B
2. Press the green X on the toolbar
3. For variable name, type in PasswordParts
4. For variable type, select string.
5. Click on the array checkbox.
6. Type in 6 for array elements.
7. Press OK.

I am going to list all the variables you need now, as another suggestion from linkmaster23: (this also includes load code variables)

Variable Type : Variable Name


current_pswd_part : Integer
final_password : String
hero_of_player_1 : Unit
loadstring : String
oldstop : Integer
Password_before_encrypt_1 : String
Password_before_encrypt_2 : String
Passwordparts : String Array (6)
temporary_password_string : String
Unencrypt1 : String
Unencrypt2 : String



Done? Yes its a lot of work, but its easier then doing it as you go.


Anyway... Now you need to find your trigger where you create a hero for the player and have the game recognize him as the right hero. If you just created a hero for player 1 in your trigger, then do something like this


So now you have a variable containing the hero of player 1. If he already exists, it might looks something like this:




Part 3: Getting the stats of the hero and entering them in.

Now that we have the hero in a variable, we can fill up that variable we made earlier, PasswordParts, with things related to the hero or player that we want to save till the next game. Here is how we get the experience of the hero:




P.S.S.S. If you have an RPG where you buy tomes, you will need three more spots in your passwordparts array to hold the unit's stats.

Part 4: Getting the Hero and entering him in.

You will need a different number for each hero you have. If you have only 10 (or less) heroes, your in luck, and only need 1 number. However, if you have at least 11 or more, you will need 2 numbers to represent them. This is because you can use numbers to represent heroes. For example, the numbers 0123456789 could all represent a separate hero. But once you get past 9 you need two digits to store the hero: 10,11,12 and so on.

We already have a variable for the hero of player 1, so we can use it to get the hero's information.

So anyway, let me show you some of the trigger. You'll have to write the whole thing out; I'll just demonstrate a part of it.


Part 5: Combining the parts into a password.
Now we need to combine these array elements into a password. You might be thinking i am just going to concatenate these strings into a password. This would be a terrible idea, because it would be incredibly easy to crack.

My idea, be it not too complex, is to first reverse the entire string, then use a rather simple encryption to encode it (in fact, extremely simple). Here is how I will do it:




What does this do?

We take our variable, Password_before_encrypt_1, and then we go through each array element of passwordparts[] and we add it on to the variable Password_before_encrypt_1, with a dash to separate them, except the last one (#6), which doesn't need to be seperated. So if we have 66 for one and 33 for another, we get 66-33. The dash will be more important later.



What does that do?

It reverses the string.


HOW?!? HOW DOES THAT WORK??
Guess I better explain it.

The meat of the code is at
(Substring(Password_before_encrypt_1, ((Length of Password_before_encrypt_1) - (Integer A)), (((Length of Password_before_encrypt_1) - (Integer A))))))

If your anything like me you get freaked out by long pieces of confusing code, but this is pretty simple. This means to use Password_before_encrypt_1 as the substring string. That parts easy enough. But what is ((Length of Password_before_encrypt_1) - (Integer A))? I could say its a tried and true reverse algorithm. In fact, I could say this whole thing is. But, what that does is it takes the length of the string, and subtracts it from the Integer A. This basically reverses the value of integer A with respect to the length of the string. I'm sure that made no sense, consider this. If you reverse Int. A with a str. length of 8, and Int. A is 0, it will come out as 8.

So for instance say you have a 3 letter string "cat". The value of Integer A would be 0. Three (length of "cat") minus Zero gives... 3, meaning to use the third character. That just happens to be the last character. So good so far. Then it goes on. 3 - 1 gives two, the second to last character. And 3-2 gives 1, the location of the first character. Notice that I say
For each (Integer A) from 0 to ((Length of Password_before_encrypt_1) - 1),...

It needs to start at zero to get the character right. Now you know why.


Writing the code backwards is practically the easiest to break encryption. Remember that I wrote this save/load for the concepts, not the incredibly hard to crack encryption.


And then to the actual encryption:

What does that do? Here goes: Say you take a number, like 7. subtract that number from 9. you get 2 (9-7). Just like if you take 4, 9-4 gives 5. Thats what I do to each number in the password. Easy to break, yes. Easy to guess, yes. Teach you what to do, yes. (That last one is the only important one)


Now how does that WORK?
Whatever that is, it needs to stop, it's annoying. Anyway, on to code dissecting.

Set final_password = (final_password + (String((9 - (Integer((Substring(Password_before_encrypt_2, (Integer A), (Integer A)))))))))

Seems to be the most confusing part. What this does , in reality, is simple. Take the character. (we already made sure it wasn't a dash in the if/then/else) take 9 minus that character (the character is turned into an integer to make that possible). Then we turn that back into a string, and add it on to the final password. It inst really that confusing, it's just long. Just subtract nine, and done.


And don't forget the best part!


I hope you knew that that displays the text to the player.


I know that that is an INCREDIBLY easy code, and also pretty easy to hack. This tutorial is just for showing people how to do it. It is not for the big, impossible to hack code.

Part 6: The end of the Save Code…

I only left out one thing. Its pretty advanced, and the other reason I left it out is it pertains to your rpg more then just some generic one.

That would be the items. My idea is that you give each item it's own letter/number/symbol. So perhaps a potion of healing would get an H, where a mask of death a %. Then you could just put these symbols in the code, somewhere. Since there are (I think) 95 keys on the keyboard, you shouldn’t run out unless you have a HUGE rpg. (Then just use two keys!!)


Part 8: Load code
Ok, this isn’t that hard. What we have to do is basically reverse everything we did to encrypt and concatenate it.

Well, here goes.






Optional Part 9: It’s not over yet!

Now that you have your password system up + running, let’s make it a bit tougher to break. (Also, let’s see if I really do know what I'm talking about)

It’s called an optional section because you can opt not to do it, but I recommend you do for difficulty of cracking the code.
Part 9, subsection 1: Checksums
Eh? What’s a checksum?
Part 9, subsection 1, subsubsection 1: What is a checksum?
A checksum is a type of number that you can use to check to see if the whole thing’s in order. It’s not only used for password systems, people also use it for things like downloaded applications to check if the app downloaded right.

Part 9, subsection 2: My Idea

After thinking this through, I think a good way to do it would be to add the first + second digits, then subtract the third. Add that to the fourth, and then subtract that from the fifth… and so on (it’s not advanced or anything, but I believe that even in its simplicity it will delay the average cracker). If you end up with a negative number, make it positive. If you get a number that has more then one digit, then add the digits together. Then put all these numbers together and put them into the 7th (is it actually the 7th?) passwordpart. (for the paranoid, you could do the same thing for the checksum passwordpart and add that on as the last digit :p)

Part 9, subsection 3: Implementation

(Implementation means the code)

Part 9, subsection 3, subsubsection 1: Variables

New variables because this is an optional section. (Yup, that’s my excuse)
Here we go again…
Variable name
Variable Type
Add : Boolean
CurrentChecksumValue : Integer

Part 9, subsection 3, subsubsection 1, subsubsubsection 1: What is a Boolean?

If you don’t know what a Boolean is, don’t panic. Actually do panic. But it wont help you. A Boolean is a variable that can either store true or false. In this case I will set it to true if you are adding numbers and false if you are subtracting.
Part 9, subsection 3, subsubsection 2: The code

I’m using the same method of writing code as previously. Where you want to put this function is after storing all the password parts, but before encrypting them.


(I've lost the actual code for this, so you'll have to deal with poor formatting. :p)


What you need to do to check the checksum is do the exact same thing you did here (except you don’t store the number in passwordparts.) Then check each number individually to see if it matches up with the typed in code. If it doesn’t, no hero! What this does is make experimentation with the code difficult (because you cant change one number because then the ultimate checksum isn’t changed, so you will need to change the checksum as well, and then if you followed my paranoid advice you would have to change the third digit as well.










Last update 01/15/06

-johnfn

Ah great ^^ the big tutorial I downloaded, but didn't read is back online :)

Haha. Why so it is :P

Woa!
Thanks!
I was searching for an Good Save/Load system!
Reputation for you! ;)

could you try make it bbcode based or would you let me to do the conversion? I don't want the tutorial to be downloadable but just readable that's it. mostly cause it is too much of a problem and the contents of the tutorial don't get indexed in the search engine

I can do that. I was getting to work on it before and I was trying to make the trigger tags work and it was too much trouble and then turned my computer off forgetting about it.

trigger tags just require to use Copy As text in the editor nothing more

Yeah but I thought I had lost the triggers until just now when miraculously I found them. Everything seems to be in working order now.

Ok I got the code to work, though the hero spawns in the middle and also the code mostly looks like:

990--9-9-9--82--9-9Is

Very much - in it. Is it supposed to be like that or did I do something wrong?
Can post the trigger if you want to take a look at it

BTW. really nice tutorial, tried to get it after the site moved though the link was gone then, really needed this tutorial!
rep.

Post the trigger. A lot of people had problems with 9s last time but I was too lazy to check it out, lets see if I can't figure out what happened here. It sounds to me like somehow none of the indicies of the PasswordParts variable were filled to me.

and oh for your information, I did set the hero_of_player_1 to a paladin.
A thing that was unclear to me was where I should put
in the


And well the one I just showed was maybe a little exaggerated. but atleast 50% or more of the numbers are 9.
But the real thing that bothers me is why it is so many -'s, doesnt look very pretty with
990--9-9-9--82--9-9Is

When I read the tutorial I hoped it would be something like
4215-1235-2364
or maybe because the trigger contained so many Integer A X - 6
134613-164123

(mark that I didn't fully understand the whole thing. Though the most of it. Maybe if I would be more concentrated I would be now as I only wanted to test it I wasn't)

btw. sry for long post :P

I'm sorry about this, but would you mind sending the map? It'd be a lot easier if I could debug as I went along.

here it is

Can you mind reading the
"(Integer A) Equal to (Length of unencrypt2) Alternatively, check to see if its the last one, then automatically end the passwordpart."
part?
I edited the previous post.

If i cant get this to work in the way I want it I guess I will have to do my own code :P
which will probably just be something like
Paladin = ah
Mountain King = ea

and so one, very easy to crack in other words.
Still.. the map Im making is mostly for LAN party's,

I dont really mind if someone figures out the code and make a uber hero. I'll just feel sorry for him to miss the whole game, I dont think they will think its fun for to long to run around with uber stuff.

It turns out that that hero save and load system there works fine. It's just that since your gold, wood, experiance, and hero level were all 0, 9-0 is 0 and it comes out with a lot of 9s. As for the dashes I think thats what happens when a 0 gets turned into a string, it just turns into "" and then the two dashes get stuck together. I'd say to just keep it like that for now. It'll look better when you have tons of gold and stuff :D

ok, I'll test it in a normal map later : P

EDIT: I dont think the triggers work.
I made a test map with tomes and leveled the hero to lvl 6.
when I loaded I got a lvl 1 paladin.

Also, wtf is up with this code I got??
0-0-0-190-0-0-1750-0-0-10-0-0-18-9-9-98-9-9-98-9-9-9428-9-9-97-9-9-9948-9-9-9428-9-9-9

(its a lvl 3 archmage)