i working on ClamAV antivirus database.
ZMD one of clamav database file who store information about malice's zip file.
i need to get this information from zip file but if possible not use any component
is encryption.
normal size
compressed size
CRC32
compression method
please help me.
You can use unzip -l to list the contents or you can write your own zip format decoder to extract the information from the headers. The format is documented in the .ZIP File Format Specification.
Related
I am using Data flow templates API to decompress a zipped file I have in Google Storage Bucket. This zip file in turn has multiple folders and files. Now the Data flow api decompresses my zip file but writes the output into a plain text file. What I want is only unzipping of my input file and extract all contents within. How can I do this?
My zip contains following heirarchy
file.zip
|
|_folder1
| |
| |_file1
| |_file2
| |_file3
|_file
Thanks in advance!
The pipeline print only the file in failure in a plain text file. You can see the detail of the process here
Are you sure that your files are readable and well decompressed?
I was able to compress and decompress files using Data flow from console.
On the settings it says: Bulk Decompress Cloud Storage Files template
Required Parameters. The input filepattern to read from (e.g.,
gs://bucket-name/uncompressed/*.gz).
So the compressing/decompressing works at the level of files, by matching the pattern. I do not know how did you compressed or decompressed at the level of folders. When I try to input a folder name for the input parameter I get: "No files matched spec Error."
this is the first time I write on StackOverflow. My question is the following.
I am trying to write a OneDrive C++ API based on the cpprest sdk CasaBlanca project:
https://casablanca.codeplex.com/
In particular, I am currently implementing read operations on OneDrive files.
Actually, I have been able to download a whole file with the following code:
http_client api(U("https://apis.live.net/v5.0/"), m_http_config);
api.request(methods::GET, file_id +L"/content" ).then([=](http_response response){
return response.body();
}).then([=]( istream is){
streambuf<uint8_t> rwbuf = file_buffer<uint8_t>::open(L"test.txt").get();
is.read_to_end(rwbuf).get();
rwbuf.close();
}).wait()
This code is basically downloading the whole file on the computer (file_id is the id of the file I am trying to download). Of course, I can extract an inputstream from the file and using it to read the file.
However, this could give me issues if the file is big. What I had in mind was to download a part of the file while the caller was reading it (and caching that part if he came back).
Then, my question would be:
Is it possible, using the OneDrive REST + cpprest downloading a part of a file stored on OneDrive. I have found that uploading files in chunks seems apparently not possible (Chunked upload (resumable upload) for OneDrive?). Is this true also for the download?
Thank you in advance for your time.
Best regards,
Giuseppe
OneDrive supports byte range reads. And so you should be able to request chunks of whatever size you want by adding a Range header.
For example,
GET /v5.0/<fileid>/content
Range: bytes=0-1023
This will fetch the first KB of the file.
Hi Guys I need a zip library with which I will be able to validate the file. I would like to read the crc from the zip header using this library and compare it with my own calculated crc. Could you suggest me any??
zlib should be enough. Take a look here: http://zlib.net/manual.html#Checksum
Once upon a time I've used this:
http://zziplib.sourceforge.net/
But nowadays I use my own code, as others suggest.
The format of zip files is very simple, so you don't really need a library to read them. You can find the complete specification for zip files here. It should take you no more than an hour to write some code to locate the zip 'local file header' of interest in the archive and extract the CRC32.
I did search for this topic, but I didn't find any relevant clue for this.
Can anyone give me some tips or demo code that can solve the problem?
Thanks in advance.
---FYI---
What I wanna do here is to zip files and upload to remote PC.
I think it'll take the following steps:
a) initialize a zipped file head and send to remote PC and save that zipped file head.
b) open file to read a portion of file data and zip the file data locally.
c) send zipped data through a pipe (tcp or udp for example) to remote PC.
d) save the data from pipe, which is zipped, on the remote PC.
e) if there are multiple files, come back to b)
e) when all files is zipped and transferred to remote PC, then close zipped file.
Two question here:
a) compress/decompress
b) File format
Thanks guys!
zlib zips a single stream. If you want to zip multiple files, you need to do one of two things:
Define a format (or use an existing format) that combines multiple files into one stream, then zip that; or
Zip each file individually, then use some format to combine those into one output file.
If you take the first option, using the existing tar format to combine the files, you will be producing a .tar.Z file which can be extracted with standard tools, so this is a good way to go. You can use libtar to generate a tar archive.
I have built a wrapper around minizip adding some features that I needed and making it nicer to use it. Is does use the latest c++11 and is developed using Visual Studio 2013 (should be portable, but i havent tested it on unix)
There's a full description here: https://github.com/sebastiandev/zipper
but is as simple as you can get:
Zipper zipper("ziptest.zip");
zipper.add("somefile.txt");
zipper.add("myFolder");
zipper.close();
you can zip entire folders, streams, vectors, etc. Also a nice feature is doing everything entirely in memory.
I'm working on application that must enrypt and zip files. So, I create some data in memory (text, binary or whatever), encrypt it and save to disk (file1 and file2). The I call e.g. "zip out.zip file1 file2 ".
I do not want to save this files to disk, but immediately create zip and pack these files from memory.
How should I do that?
Thanks a lot!
You could try to use the zlib library to be able to create zip files from memory buffers.
The boost:iostreams could also be a good solution.
For zlib there is an extension for zip called minizip in the contribs. For minizip you can find code to work with in-memory buffers on the authors page:
Justin Fletcher wrote a very simple implementation of a memory access method for the ioapi code (ioapi_mem_c.zip).
Note that you must compress first and then encrypt. Encrypted data can't be compressed anymore.
Interestingly enough, I wasn't able to find a library to create ZIP files from C. zlib only allows to (de-)compress individual entries in a ZIP archive.
It comes with contrib/minizip; maybe that can get you started.