How to debug a .zip generator algorithm? - zip

I'm trying to implement a minimal version of .zip file generation following this spec: https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
I don't actually need compression, I just need a way to string together a bunch of files into a single widely adopted archive format with the capability to stream in file data while streaming out the zip.
So far I'm partially successful, 7-zip and windows built in zip extractor can extract them just fine, winrar and macos built in zip extractor are giving me corrupted archive errors.
I can't for the life of me find the actual problem(s?) though, as far as I can tell the .zips are built 100% to the specification but the spec is a big wall of text and with swooping changes from one zip file version to the next along with legacy attributes taking on new functions it is tad confusing.
Does anyone know of an extraction tool that can give me more specific errors than just "archive is corrupt"?
Or perhaps a zip generation utility where I can pick and choose between all the different ways of building a zip file so I can go and compare the results byte by byte?

Does anyone know of an extraction tool that can give me more specific errors than just "archive is corrupt"?
The unzipada tool # Zip-Ada project will do exactly that
Testing archive ko.zip
raised ZIP.ARCHIVE_CORRUPTED : Bad (or no) end-of-central-directory
[C:\Ada\za\unzipada.exe]
Zip.Find_First_Offset at zip.adb:589
Unzip.Extract at unzip.adb:667
Unzipada at unzipada.adb:259
By browsing the code (like: zip.adb, line 589) you can narrow down the corrupt archive issues. For building the tool, download the sources and follow the readme.txt file. There are also pre-built binaries for Windows.

Related

collada2gltf converter can't produce *.json file

I am reading a book: Programming 3D Applications with HTML5 and WebG , it involve a Vizi framework.
All the examples load the *.json file instead of *.gltf file. Why?
When I load *.gltf, it doesn't load any result, and the collada2gltf converters only produce *.gltf, *.bin, *.glsl files and so on.
What should I do?
.gltf is a JSON file. Try to open it with a text editor and see for youself. .bin and .glsl files are just additional resources, linked from .gltf file. Those are geometry buffers and shaders respectively. So to make it work you should make sure that all the files produced with the converter are also available to a web browser you running your code in.
Also you can try to add -e CLI flag to collada2gltf and it'll embed all the resources into result .gltf file.

How can I tell what language a file is written in?

I've been trying to find, for a long time, what language this file is written in so that I can decompile it. I have tried to decompile as .luac, .class and also tried to open it as .jar and .rar and .zip.
Although the file extension is .car I have never seen this extension before and there certainly aren't any openers for it on the internet. I have even gone to the point of finding a .car opener, but it wasn't for my .car.
So, I suspect it has just been renamed.
Can anyone tell me what language it is coded in?
I don't know if I'm allowed to post files here, as I have only just joined, but here is a Dropbox link to the file: https://www.dropbox.com/s/y6jd62lfywoskqi/code.car?dl=1
Any help would be appreciated. This is the first line in Notepad++:
rac T D ` constants.lu œÂ tools.stashsaver.lu à scenes.sellitems.lu ˆî scenes.draw.lu ¼ gui.menu.lu 6 scenes.missions.lu ˆP
A quick dump of the file leads to several URLs referencing:
http://www.coronalabs.com/
So based on this I'd say the file was created with the SDK they offer.
https://coronalabs.com/products/corona-sdk/
Corona lets developers use integrated Lua, layered on top of
C++/OpenGL, to build graphic applications. https://en.wikipedia.org/wiki/Corona_%28software%29

save MATLAB code file along with results in one folder?

I'm processing a data set and running into a problem - although I xlswrite all the relevant output variables to a big Excel file that is timestamped, I don't save the code that actually generated that result. So if I try to recreate a certain set of results, I can't do it without relying on memory (which is obviously not a good plan). I'd like to know if there's a command(s) that will help me save the m-files used to generate the output Excel file, as well as the Excel file itself, in a folder I can name and timestamp so I don't have to do this manually.
In my perfect world I would run the master code file that calls 4 or 5 other function m-files, then all those m-files would be saved along with the Excel output to a folder names results_YYYYMMDDTIME. Does this functionality exist? I can't seem to find it.
There's no such functionality built in.
You could build a dependency tree of your main function by using depfun with mfilename.
depfun(mfilename()) will return a list of all functions/m-files that are called by the currently executing m-file.
This will include all files that come as MATLAB builtins, you might want to remove those (and only record the MATLAB version in your excel sheet).
As pseudocode:
% get all files:
dependencies = depfun(mfilename());
for all dependencies:
if not a matlab-builtin:
copyfile(dependency, your_folder)
As a "long term" solution you might want to check if using a version control system like subversion, mercurial (or one of many others) would be applicable in your case.
In larger projects this is preferred way to record the version of source code used to produce a certain result.

Artefact folder structure does not contain empty directories

I'm trying to store whole the output of my build, this includes some empty folders. These aren't included by the artefact mechanism in teamcity:
What doesn't work:
OAR\=> OAR.zip
OAR->OAR.zip
OAR
Inside of OAR i have a folder structure that needs to be stored. I know i could put a placeholder file in each but that is not the answer i'm after. Otherwise ill have to zip it myself?
Unfortunately TeamCity, by design, searches for files and uploads them as artifacts which means that empty folders are never included. Given the open and very old issue in the TeamCity tracker I doubt they are going to fix it any time soon.
I would recommend zipping the folder yourself, that is the approach we have taken. How you implement that depends on the build technology you are using. For example, if you are building using Nant you could add the zip task to your build, there are similar options for MSBuild and Ant.
If you don't want to rely on the build performing the zip I would recommend installing 7zip on your build agents and using the command line to perform the zip. Just remember if you want 7zip to include empty directories use * as the wildcard rather than *. * like so:
7z a -r OAR.zip *
Technically you could use powershell to do the zipping, which would be better than having to install something on your agents. I haven't tried this option myself.
Apologies for not linking all my references above. Apparently, and understandably so, I need at least 10 reputation to post more than 2 links.

Deal with ZIP-Buffer in node.js

I am building the server part of a webapp, using node.js. This involves getting data from thetvdb.com (API documentation of thetvdb).
The data comes as a zip file. HTTP download is no problem, however, parsing the file is. I actually never save the file, but just keep it in memory, as suggested in How to download and unzip a zip file in memory in NodeJs?
I have a buffer with valid data (same data as when I download the file with browser/curl...). However, adm-zip (I also tired other zip libraries, some suggest invalid zip length) can't open it. It does not show an error, but the zipEntries in the end have length of 0.
When I write out the buffer to the filesystem and open it with gui or cli tools it works.
I can't give a direkt link to the file, as it would involve my API key, however I re-uploaded it here.
I think I might have an answer for you:
Don't rely on npm install. I just ran the example that you linked to with the zip file you provided, and I get an output of "0".
I saw a comment on that other StackOverflow page, saying that the version of adm-zip on npm is not up to date. I grabbed a fresh copy of adm-zip from github, overwrote the one in my node_modules folder and reran the example code and now get the following:
...
<Actor>
<id>237811</id>
<Image>actors/237811.jpg</Image>
<Name>Peter Pratt</Name>
<Role>The Master</Role>
<SortOrder>3</SortOrder>
</Actor>
<Actor>
<id>23780s/237811.jpg</Image>
Give that a shot!

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