comparing files? - GameCreators Forum

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Mugen Wizardry

User Banned

Posted: 22nd Jan 2011 02:21

Hi all. I'm having a bit of a problem comparing 1 file with another.

for now i have them both in the same folder, but when i release my program to the public, i would like 1 file to be in 1 place, and the other to be in the other place, and compare files. if 1 is not EXACTLY the same as the other, then u've hacked the file. if 1 of the files are missing then uve deleted on purpose or hacked the file.

i would like a simple answer plz & thank you

Here is the code I wrote:

+ Code Snippet

open to read 1,dir temp()+"\"+"settings.dat"
  open to read 2,dir temp()+"\"+"temp0100292847745674839.dat"
  
   while file end(1)=0 and file end(2)=0
   
   read string 1,i$
   read string 2,i1$

  print i$
  print i1$
       
      sync
   endwhile
         
  close file 1
  close file 2

//compare file 1 with file 2
//if both files are not equal then end
  
  if i$<>i1$
  end
  endif
    
  close file 1
  close file 2

thanks! ^^

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Kevin Picone

23

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Joined: 27th Aug 2002

Location: Australia

Posted: 22nd Jan 2011 02:41

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Check the length of the files. If the lengths aren't equal, then they can't match.

If the sizes are the same, then compare the raw data.

--> Load the data from file #1 into a memory bank
--> Load the data from file #2 into a memory bank

----> Loop through each byte and compare them. If any bytes aren't the same, the files don't match.

Hmm, I wonder what's coming in 2011?

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mr_d

DBPro Tool Maker

19

Years of Service

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Joined: 26th Mar 2007

Location: Somewhere In Australia

Posted: 24th Jan 2011 02:51

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As Kevin said, first compare sizes to get a "rough" compare result, and if they are the same size then go further.
If the files are relatively small (say less than about 2Mb) then a byte by byte compare would be fine, if they are larger then I'd go with another method; maybe better to compare the hash of each file.
IanM's Matrix plugin has lots of hash functions that would suffice.

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