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donn



Joined: 05 Mar 2010
Posts: 199
donn
Hi,

This may be the wrong topic for this question, but I'm looking for advice/best practices for editing existing files in Windows.

Let's say we have a very large file and you just need to remove the 20th byte in the file. I understand if there are bytes at the end, you can truncate it, but the beginning seems trickier. In the meantime, I'm going the rewrite route.

For less complicated, maybe smaller files, and depending on the needs, it may be advantageous to save parts of the file as separate files and just update each one. But what about much larger files and the case where there is only one file being edited? Rewriting the entire file seems like it would take a huge performance hit for a small removal.


Thanks a lot
Post 07 Jun 2016, 22:02
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Grom PE



Joined: 13 Mar 2008
Posts: 115
Location: i@grompe.org.ru
Grom PE
There's no way around rewriting the rest of the file.
File formats are usually designed in a way that such cutting doesn't happen often.
Post 07 Jun 2016, 23:20
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donn



Joined: 05 Mar 2010
Posts: 199
donn
That's too bad, but it makes sense if sequential addressing would become disjointed with gaps in the file.

Appreciated. Will need to research this more, but at least this allows us to get creative and come up with our own solutions.
Post 08 Jun 2016, 00:06
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17715
Location: In your JS exploiting you and your system
revolution
If the file is a simple linear format, like a text file, then your only option in all officially supported Windows file systems is to rewrite the entire remainder of the file.

But if the file is more structured, like exe or dll files, then in many cases you will only need to rewrite the affected section.
Post 08 Jun 2016, 05:13
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