Hotfix/patches

Hello.
Question.

Lets say I write an executable program that is supposed to do

A+B+C

but i made a mistake and it does
A+B-C

and i only discovered this error after i built the program and sold it so someone.
how do i write a separate executable / patch i can send to the person that will correct that error IN c++.
Thank YOU

 

send him the executable file to overwrite the wrong one

 

well yes...but...im thinking if its a big program. Cant I just write up a little code that will do that?instead of the WHOleeeee Executable?

 

then try the patch method

read both files and find the differences(what the difference is and where)
write the data in a file
and send this with an exe patcher program to issue the changes to the old program

 

ok with this patch method if you have four forms will you be able to specify that you only want to check out the code on the 1st form?

 

thanks

 

what for

 

you check only the executable file

 

ok so i must redo the whole executable?

 

this is patch1.cpp

Code:

#include <stdio.h>

int main(){
    int A=1,B=2,C=0;
    C=A+B;
    printf("\nC=%d",C);
    getchar();
    return 0;
}

this patch2.cpp

Code:

#include <stdio.h>

int main(){
    int A=1,B=2,C=0;
    C=A-B;
    printf("\nC=%d",C);
    getchar();
    return 0;
}

patch2.cpp is the program with the error and patch1.cpp is the correct one

you compile both of them

if you see the executables in a hex editor and compare them with each other
you will see that most of the files are the same.
you need to change only the differences

in dos prompt you can use fc=filecompare like this
fc patch1.exe patch2.exe >differences.txt

in this text file you will see what you have to change in patch2.exe in order to become patch1.exe

see the files in the zip file.


p.s. all the above must be done programatically by you
or you can use something like this to do it automatically http://sourceforge.net/projects/jojodiff/



also another article based on what you want is here http://www.codediesel.com/tools/transferring-psd-files-quickly/

 

Thanks! for this example im going to try to recreate it now

 

Hello so i did the did what u said and got this Long output with everything being different and wondering how I change this to a patch and then integrate it into patch1.

Ive also been reading on Jojodif and it seems to be what im looking for. Tried it and seems to work but ill like to run the procedures over with you.

So 1st i remaned my patches,
so Patchm1 gives the output of

Code:

C=-1

//1-2
and Patch3 is C=3//2+1

so lets call Patchm1 the error and Patch3 the revision.

So i did Jdiff patchm1.exe patch3.exe patch.p
( First question:Is this the correct extension to use )

then i did:Jptch patchm1.exe patch.p patch3
(Thou i saw this in the example is causes the exe too bug out so i did)

jptch patchm1.exe patch.p patch2
So running Patch2 gave me"C=3"

Therefore what I gather is
Jdiff patchm1.exe patch3.exe patch.p
Writes the difference into patch.p which is 1+2 into patch.p instead of 1-2
and
Jptch patchm1.exe patch.p patch3
writes that into patch3?

 

the extension of the patch file is something for you to decide
you could use ptc to know its a patch file or whatever,just try to avoid
known types of files like txt,exe,com,bat,jpg,... for obvious reasons.

and finally
Jptch patchm1.exe patch.p patch3

convert it to

Jptch patchm1.exe patch.p newpatch3.exe

 

Once again thanks for the help but...this isnt patching how id like.

I added a simple line to patchm1.exe changed it too
Hello
c=-1

then i do
Jdiff patchm1.exe patch3.exe patch.p
jptch patchm1.exe patch.p newpatch.exe

this outputs C=3 without the Hello
which is basically the data in patch3.exe

Jdiff patch3.exe patchm1.exe patch.p
jptch patch3.exe patch.p newpatch.exe

outputs hello c=-1 which is patchm1.exe's data

and when i do
Jdiff patch3.exe patchm1.exe patch.p
jptch patchm1.exe patch.p newpatch.exe

it doesnt work so im stuck :embarasse
cause im lookin for
hello
c=3

 

are you sure that you open this program?---->newpatch.exe
and not patch3.exe?

 

yes very sure.
I also keep getting the error "this version of the file is not compact. with my version of windows, im using a 64 bit visa

 

Would you like me upload the files?

 

yes

 

ok here it is,i also uploaded a screen shot of the commands i wrote.Thank you

 

simple mathematics
===================
A-B=C
A+C=B

jdiff patchm1.exe patch3.exe patch.p------>A(patchm1.exe) - B(patch3.exe) = C(patch.p)
jptch patchm1.exe patch.p newpatch.exe--->A(patchm1.exe)+C(patch.p)=B(patch3.exe)=(newpatch.exe)


how it works,generally idea
======================================================
-You sent the wrong program named patchm1.exe to a user that bought your program
So he has already patchm1.exe in his computer

-Then you figure out that there is a bug to fix
You fix it and make a new program called patch3.exe

-instead of sending the patch3.exe to your user you decide to send him only
the differences between the program with the bug and the one without it.
So you send patch.p to him

-He uses the jptch program to bring his file to the new version without the bug