File In / Out Question

ok i hoping some much someone would finaly answer this question for me...


every time i see a new game comes out and there this smart person make some sort of program the would change stuff in the file. e.x save game editor, file editor the extract files, etc.. you problably get the idea, i want to know how do they do it ? where do they get knowledge from ? how can they understand these files?

what would make me better at file I/O ?

i try to find some C programiing file I/O advance tutorial but no luck i just run into newbie stuff..

i hope you could help me and thank you for your time..

usually the developers tell them how the files are written, other times people just read in some data and see what they get.

The best way to find out stuff like that is first learn binary and depending on how deep you want to get into stuff like that ASM. File editors are mainly done by first finding the values manually (Examples below) and then once the value is found then they know the offset of were information is stored. Thats how hack files mainly work. As for in game hacks thats is where asm comes in. First you need to find the spot to offset in memory from the start of the program. So you need to hook the program and then move that much into memory to change the values.

Example: (Hack Save File)
Lets say your playing a rpg and you want to hack your strength. YOu first find one value (lets say 55). You convert it to hex and save the game. Now you open the sav file in a hex editor and find the offset of every 55 value in the binary file. Then you return to the game get another value of strength (you level up your guy one level and now have 57 strength). Now you again go back to the hex file locate all the 57 values and compare them to the prevoius value and then remove ones that are no long the same offset. Eventually you will either have only one value or a few and you try to edit the values. Some files store multiple copies of the same value for protection against hacking other will use in game checking so sometimes that not possible to hack unless you have all values or something like that.

So anyways i hope this helps if you need more info email me at [email protected]. I did lots of this for a few years so i am still pretty well knowledgable.