Does anyone know how to read self extracting zip?

[John Kovacich]

I have a job which reads files from various organizations across the US.
Most files are submitted using a standard format, but some organizations
refuse to adopt the standards and submit files which are zipped, in excel
format, or just make up their own format. My job opens the files an searches
for identifying keywords which it uses to determine where to store the data.
I can open the zip, excel, CSV and SYLK files ok, but one organization
is sending self-extracting zip files.

There is no way I can justify the risk involved with trying to execute
one of these exe files. Does anyone know how to strip off the self extracting
code, leaving a good old fashioned zip file?



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Thanks,

John Kovacich

[Edwin Knoppert]

Pkunzip unzips them too (afaik)

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[Bob Houle]

John,
I didn't think it could be done, but I went to my favorite ZIP
program's website ( www.rarsoft.com ) and pulled this from their
Main page:

" WinRAR offers the ability to create and change SFX archives
using default and external SFX modules." (SFX mean self extracting
files or EXE's)

Check it out,
--Bob

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[Tom Hanlin]

Self-extracting .EXE files... well, it depends a lot on what they were
created with. Most ZIP-based SFX creators just encapsulate normal .ZIP
information inside the .EXE file, so any decent unzipper can deal with
them normally.

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Tom Hanlin
PowerBASIC Staff

[Bern Ertl]

John, were you asking for a program to strip the .EXE off, or for
help coding this feature into your own program?



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Bernard Ertl

[John Kovacich]

Bernard,
I need to do this from within my program. I currently use two different DLL's to
read zips (ZLIB is one). I will see if either of them can read the
files as-is. I was assuming that I would need to strip of some encapsulating
code, leaving me with a nice clean zip file.

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Thanks,

John Kovacich

[Peter Redei]

The self extracting zipfile starts with the code and followed with the zipfile after it. A normal zipfile should start with a signature of "PK", while in a self extracting archive the signature is changing to "MZ".
I think searching for the signature will tell you where the zipfile starts and than you can strip it off and changing the MZ back to PK.

I hope this helps.


Sincerely,


Peter Redei

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