I am writing a program that downloads tar.xz files from a server and extracts them in a certain place. I am struggling to find a away of extracting the tar.xz file in the certain place. I am using Qt so a more Qt-way of doing it would be useful, but I don't really mind.
There is no support for archives in Qt. You can either have a look at the KDE library which offers support for virtual file systems or you can use QProcess to call tar directly. Use -C <dir> (uppercase C) to specify the directory to extract to.
[EDIT] There also is libtar (BSD license).
Related
According to the 7zip documentation, the formats that 7zip supports are:
Packing / unpacking: 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM
Unpacking only: AR, ARJ, CAB, CHM, CPIO, CramFS, DMG, EXT, FAT, GPT, HFS, IHEX, ISO, LZH, LZMA, MBR, MSI, NSIS, NTFS, QCOW2, RAR, RPM, SquashFS, UDF, UEFI, VDI, VHD, VMDK, WIM, XAR and Z.
I wanted to ask, if I use 7zip to unpack a chm file. How can I pack it back?
I see that 7zip does not support this, so who does?
I would like to take the files that 7zip unpacked (from the chm file) and create back a CHM file.
Is that possible?
If you have only the CHM file, there is no easy way to do this and you need reverse-engineering like mentioned by #Mark.
So you have to decompile the CHM file and compile again by HTML Help Workshop - a free CHM compiler created by Microsoft many years ago - or by another help authoring tool.
Edit 2023-01-11:
I've archived a copy of the HTML Help Workshop installer
Microsoft HTML Help Downloads (the download links are broken and dropped by Microsoft)
If you really want to start with Reverse Engineering a first step of decompiling is described at HTMLHelp command-line. Search for: Example of using HH.EXE to decompile a CHM help file.
You know, you can use 7Zip or just open a command prompt window on a Windows PC and type the following:
hh.exe -decompile <target_directory> <path>\<filename>.chm
The only decompiler with any additional features is KeyTools as this can try to rebuild the project (.hhp) file. You'll need this file if you want to recompile the help project.
One thing to note is that the decompile/recompile process isn't a "round-trip" process. Certain features that the help author added to the original help file can't be recovered when you decompile it, so these may no longer work properly after you've recompiled.
This is especially true in the area of context-sensitive help, which may be broken in the new version of the file.
Only if you have some internal Microsoft utility to do that, since that is their proprietary format, or you write your own using information from reverse-engineering the format.
In my linux program, I want to decompress a tar.gz file contents to a specific directory. Is there any system call or any C++ class available in C/C++ to extract file contents from tar.gz file?
There is excellent library libarchive, which supports accessing multiple archive formats using consistent API. You can follow these examples on how to use it.
If you are on Ubuntu, you can easily install this library using command sudo apt-get install libarchive-dev. On other platforms, you may need to download source code and compile this library yourself.
One advantage of using libarchive vs. using system() calls is not depending on system utilities, and also it should work faster because it does not fork.
You can use several libs like libtar.
Or you can use a system call like you already mentioned:
system("tar -zxf /your/file.tar.gz")
I need to find a library that allows me to easily get a directory listing of all the files inside a ZIP archive and allows me to extract any given file inside the archive to memory (a buffer). Preferably, it should be a high-level library since my requirements aren't very complex (what I mentioned above is pretty much all I need).
Previously I tried PhysFS which has the behavior I need (easily access files inside an archive), but it's unsuitable because of other reasons (there are many archives and PhysFS would require me to mount all of them individually, which is not an option). Another library that kinda has the functionality I need is Chilkat, but it's shareware so I can't use it either.
Any other suggestions?
While .zip uses zlib http://zlib.net compression, it alone is not sufficient to get a directory listing from a .zip file.
You also need code that can read the .zip dictionary format. Check out Minizip http://www.winimage.com/zLibDll/minizip.html. It provides a code and simple zip/unzip command line executables.
edit 2 The code is entirely C (so is Zlib) -- the page has links to two c++ wrapper libs that both seem to be dead links.
How about zlib? http://zlib.net/ "A Massively Spiffy Yet Delicately Unobtrusive Compression Library (Also Free, Not to Mention Unencumbered by Patents)"
I'm trying to write a small, cross-platform comic book reader (Qt / C++). I don't care what's already out there, I know there are some.
My problem is that I need to read the comic book formats, which are renamed rar and zip files.
The documentation is very... nonexistent? There's no "hello archive" document anywho.
How can I set this up?
If It makes it easier to assume I'm on any particular OS, do so. I'm switching between Kubuntu, OSX, and Win7 constantly for dev work.
I've been working on a simple C++ wrapper for the 7zip SDK, which you can find here. It currently only supports Windows and the specific needs I had, but I'd be happy to make some alterations and/or accept contributions. It can extract 7zip and Zip files in a few lines of code, using the 7z.dll. RAR shouldn't be difficult to add since the DLL supports it.
7z should actually come with both source for a commandline variant and a GUI variant, you could dig into to those and see how they do the compression, else you could use unRar and see if that has any examples(unfortunatly I can't check due to the download being blocked where I am).
Poking around the LMZA SDK a bit I came across this:
ANSI-C LZMA Decoder
~~~~~~~~~~~~~~~~~~~
Please note that interfaces for ANSI-C
code were changed in LZMA SDK 4.58. If
you want to use old interfaces you can
download previous version of LZMA SDK
from sourceforge.net site.
To use ANSI-C LZMA Decoder you need
the following files:
1) LzmaDec.h + LzmaDec.c + Types.h
LzmaUtil/LzmaUtil.c is example
application that uses these files.
I'm learning C++ using Vim as an editor on Windows XP, however I found a issue that I have listed below.
I have downloaded and installed c.vim and it is a essential file, however when I start vim it shows the message C/C++ template file 'C:\Program Files\Vim\vimfiles\c-support/templates/Templates' does not exist or is not readable, How do i fix this problem?
How would i make vim compile a C++ STL file?
For your first problem: I suspect that you didn't extract all the files in the archive (that c.vim came in). The c.vim documentation (README.csupport) says:
The subdirectories in the zip archive
cvim.zip mirror the directory
structure which is needed below the
local installation directory
$HOME/.vim/ for LINUX/UNIX
($VIM/vimfiles/ for Windows)
This means that you need to uncompress the entire archive as it is into your vimfiles directory.
There are some other steps to follow, detailed in the documentation.
As for your second issue: you need a Makefile to do that. If you have never done this before, I suggest using cmake to generate a Makefile. You will also need GNU tools for Windows; Cygwin or MinGW are the most popular choices. I haven't use them, it is easier to do all this on some *nix OS :).
When done, use :cd (if you are not in your working directory), and :make. Use :cl to list the compiler output, :cn to jump to the next error. There are some other useful commands for compiling. You might find these resources useful:
StackOverflow: Recommended plugins for C coding
Compiling from Vim
C editing with Vim
Also, I found the Nerd Commenter a very useful companion.
I found that Vim acts somewhat like alien on Windows; it is designed for an *nix-like operating system. I think it is possible to craft a similar environment for it, and use it mostly successfully, but it is so much easier to do on some linux, as it is "instantly home" there.
Anyway, if you wish to stick with Windows, I think you can find a way to accomplish what you want. Good luck.
Download Vim and install to your computer.
Download c.vim and extract to $Vim\vimfiles\
Download MinGW and install to your computer, make sure that you check C++ Compiler at Select Components.
Add C:\MinGW to system Path variable
Edit _vimrc file, add set makeprg=mingw32-make after line behave mswin
Test your Vim with hello world, use !g++ c:\full_path\filename.cpp -o c:\full_path\output.exe.