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jules · Posted: Thu Sep 16, 2004 6:05 pm Post subject: Serious problem with VDSZIP

I've found a serious problem with VDSZIP. Under Windows XP SP2 if you turn on Data Execution Prevention (you can do this from Control Panel, System, Advanced, Performance Settings) it gives an error "The instruction .... referenced memory at 0x00000000, The memory could not be written."

I think newer systems have this enabled in hardware.

FreezingFire · **Admin Team** Joined: 23 Jun 2002 Posts: 3508

What is "data execution prevention"? Smile

X-Tools · Posted: Fri Sep 17, 2004 6:11 am Post subject:

I think this is the new buffer underun prevention feature in xp sp2.

jules · Posted: Fri Sep 17, 2004 7:37 am Post subject:

Well, I'm still burning coasters! Wink

I think you mean buffer overrun.

arcray · Posted: Fri Sep 17, 2004 9:04 am Post subject:

I use VDSZIP.DLL quite extensively to zip up files before encryption prior to sending by SMTP. I have found that it is becoming error prone in the wild, with error 407's

Can anyone recommend an alternative tool for zipping up files that can be used by VDS? In the office I use the winzip command line tool, but this requires a licence for each machine it is used on.

Thanks in advance

jules · Posted: Fri Sep 17, 2004 11:00 am Post subject:

You could use the InfoZip 32-bit command line tool (www.info-zip.org). I used that all the time for my internal applications. I only got VDSZIP because I didn't feel that bundling InfoZip in a shareware or freeware application was very professional, even though (subject to various conditions) the license does allow you to. Actually I still used it for my personal backup script as it is quicker than VDSZIP and also (as you have discovered) more stable.

For a long time I considered making a VDS ZIP DLL, but whenever I looked at any Zip libraries they all looked rather complicated to use and it seemed like a lot of work. Most of the DLL's I've done, even the CD burning one I did for Emmanuel, were about half a day's work, as they basically consisted of putting a VDS interface to ready-to-use functions. Using the code I've seen, a ZIP DLL would take a lot longer

I may be forced to develop one, because I have released products that require unzip and in one case zip functionality. But because of the disappointing experiences of others who have released extension DLLs, I doubt if the sales would even cover the cost of adding the features others want but my own software doesn't need, and documenting it, so I don't plan on making it generally available. There is also the matter of an agreement I have with Emmanuel, that prevents me from releasing VDS-related tools in my own right. (That wouldn't prevent any private contractual arrangements for developing a DLL, though. Wink

)

CodeScript · Posted: Fri Sep 17, 2004 11:46 am Post subject:

I remember working on a freeware win32 dll to add zip functionality that FreezingFire didn't get to work. However AFAIR the dll didn't come with a license agreement etc. Sad

Don't remember if I had posted info bou it on this forum.

vdsalchemist · Posted: Fri Sep 17, 2004 12:58 pm Post subject:

Well I thought about building a VDS Zip DLL as well but I never did pretty much for the same reasons that Jules is talking about. So I did the next best thing. My Guardian.dll uses the same compression that most Zip products use. It uses the free zlib library. It only de/compresses single files. I have not added archiving abilities yet. I will probably add that later but it will never be a Zip file since the header and tables used in Zip files are very complex and IMHO are not needed for an archive file. I built compression into Guardian because I built a program in VDS that UUEncodes files but I wanted to offer Compressed UUEncoding which is the new craze in this area. Anyway FF did submit a DLL that could build cab files I don't think its a VDS DLL. CAB actually has a better compression ratio for binary data than Zip but it too is pretty complicating.

jules · Posted: Fri Sep 17, 2004 1:26 pm Post subject:

Garrett · Posted: Fri Sep 17, 2004 2:35 pm Post subject:

And the author of the VDSZIP.DLL is not available to do any work on the
dll anymore.

FreezingFire · **Admin Team** Joined: 23 Jun 2002 Posts: 3508

I produced a example that used a non-VDS DLL that acted as a wrapper
around Microsoft's CAB10.DLL and the free ZLIB.DLL.

This has support for both CAB and ZIP compression/decompression.

You might want to take a look at it - you can download it at:
http://freezingfire.vdsworld.com/files/cab10.zip

(Contains all required DLLs, example scripts, and documentation links)

jules · Posted: Sat Sep 18, 2004 9:50 am Post subject:

That was the one I played with and had trouble with. I forget what it was I couldn't get it to do. I think this is the same one CodeScript referred to a couple of messages back.

CodeScript · Posted: Sun Sep 19, 2004 4:13 pm Post subject:

ShinobiSoft · Posted: Sun Oct 17, 2004 3:07 pm Post subject:

For those who'd like to know, I'm having minor success writing a dll for
VDS for working with zip files. Cool

As Jules posted previously, it is extremely
tricky dealing with the zip APIs. However, I feel that I may eventually get
this problem solved. As soon as I do, I'll let everyone know! Wink

Serge · Posted: Mon Oct 18, 2004 9:58 am Post subject:

sounds good - i could use a zip dll Smile

serge