I am creating a C++ program that will read a .docx's plain text. My plan of attack is to rename the .docx as a .zip and then unzip. I then will rename the .xml file containing the text of the document as a .txt and parse it out.
Right now I have figured out the renaming which was easy enough. I am now struggling with unzipping. I am very proficient in C++, but this is my first time I have been extending myself to real word applications and using it beyond the STL library.
At first I tried many wrappers for C++ from the zlib library, but have not been able to get any of them to compile or work properly (it may be due to environment being in Cygwin). For that reason it seems I have to default to using the messy zlib code to do this. But from all the documentation and examples I can find it only shows zlib being used to read a .zip that is a compression of one file not multiple files. I now don't know where to go from here and, like I said earlier, being completely new to the domain outside of STL I am feeling quite lost.
Any help or guidance is much appreciated!
Thanks,
Michael
I don't think zlib supports multi-file zips directly (could be wrong), so you may want to look for alternatives. As an aside, you might also want to consider switching from cygwin to MinGW, unless you really need the POSIX/UNIX compatibility that cygwin provides.
I've been dealing with a similar issue, but don't really have a great solution yet.
zlib does not currently support multiple files.
See: C/C++ Packing and Compression
zlib is for GZip compression, not ZIP compression (see here for details).
As a result you'd perhaps be better to shell out to the unzip utility provided in Cygwin and available for lots of platforms.
Related
This is kind of a beginner question, so please let me know if this is appropriate for this website and if not, where else I should be asking this.
I've just gotten into the basics of C++ (pretty much what's being taught in this video from FreeCodeCamp: https://www.youtube.com/watch?v=vLnPwxZdW4Y). Obviously, not everything there is to know is discussed in this tutorial and I've been running into a couple of things in other demonstration vids that I don't quite get yet.
For example, this quick demonstration of how Tetris can be coded: https://www.youtube.com/watch?v=zH_omFPqMO4&t=0m25s) you can see him use the command 'RenderWindow', which apparently creates a new window the size of his choice (320*480 pixels in this case). This doesn't seem to be a standard function in C++, so I assume he somehow imported it. How can I do this myself? Does it have to with the file inclusions written at the top of the file (#include <SFML/Graphics.hpp>)? If so, how can I learn more about such files, where can I find them (is it anything like the Python Package Index, or interfaces in Java) and can I create them myself? Any general explanatory words on this?
Thanks in advance.
This doesn't seem to be a standard function in C++
That is correct. There are no functions for graphics nor window handling in C++.
so I assume he somehow imported it. How can I do this myself?
Usually, you would pick a library of your choice (there are many), or do it yourself by using whatever API your operating system provides.
Does it have to with the file inclusions written at the top of the file (#include <SFML/Graphics.hpp>)?
Yes, SFML is one of those libraries.
If so, how can I learn more about such files
You would go to the library's homepage and read the documentation.
where can I find them
Try searching the web for lists of libraries, articles, projects, etc.
is it anything like the Python Package Index
No, there is no standard one for C++. There are several package managers, build systems, etc. Popular libraries are in most of them and support one or more build systems.
I'm trying to read MXF files (from Avid) into an Objective-C project and analyze some frames from video. Preferably getting them into a CGImage or NSImage.
I've been exploring the mxflib, but find myself at a bit of a standstill. I'm used to the mechanics of the standard video methods within Obj-c, but this package is C++ and not exactly something I'm familiar with.
Does anyone have experience working with this library or another similar one? There's not much information available on the subject (at least not that I can understand). And I'm not quite sure where to begin.
Actually, I'd say you're looking at it from a not so good way, as the mxflib is prepared to handle standard MXF files, not really Avid ones.
In short, for this to work, you need to extend the library as per Avid specs (it can be done!) or go with AMT, for which I understand you need to engage Avid to have it.
Finally, I think you're stuck with C++! ;-)
I am a frustrated newbie of C++ who would like to do the simple task of extracting a pixel matrix from an image file, do some transformation, and then output the modified matrix to an image format of my choosing.
I've given libpng a try and it's API is a mess and hardly readable. Interestingly, some people said it's the best available for C++. I gave my software developer cousin a call and he told me to use OpenGL. So, I did some Googling and I still haven't found a straight answer.
It appears getting a simple "int* readPNG(char* path)" is too much to ask for when the likes of Java, Matlab, and python have these things included in their standard libraries. This is just ridiculous! How do you pros come by and what libraries do you use?
Also a few trivial C++ questions:
- Is there any way to organize classes in a hierarchy like how packages are used in Java? I tried filters in Visual C++ but they don't seem to be the same thing.
- Is there any way to get easily comprehensible stack traces for runtime failures?
Try OpenCV. It is an image processing library with very simple features for editing and saving the images. It will serve your purpose. It also comes with very elegant documentation.
I've found ImageMagick's Magick++ library to be the most useful tool for handling image formatted data programmatically.
C++ has namespaces like Java but they are much more difficult to use and may only make things less readable. As for stack traces, I recommend combing the existing stackoverflow answers for that. In short, it's not simple.
I suggest you improve your Google-fu. There are lots of image processing libraries for C++, including the Boost Generic Image Library, which is as close to standard as you'll get. If you don't have Boost installed and minimal fuss installing libraries, you can always try The CImg Library.
As for your other questions (e.g. stack traces), you'll need to ask separate questions.
I'd suggest Magick++, the C++ API to ImageMagick.
As for packages: you can use namespaces, but that's not nearly comparable to Java's packages (no package-level access etc). They're mostly what they're called: a means to organize names.
Stack traces are not trivial in C++. And there's no platform-independent way of implementing them that I'm aware of.
If you need these features, I just wonder why you don't stick with Java or Python or the likes ? ...
1) Try freeImage - very easy to use and the documentation is readable.
freeimage site
2) for stack traces: which environment are you working with? In Visual Studio there is Stack window (Debug/Windows/Call Stack - Alt 7),
You can also use DebugView and OutputDebugString - not really traces the stack, but can be very usable in debugging. .
I recommend DevIL (formerly known as OpenIL). It has read and write support for 17 formats, and supports many more for just reading.
This is my answer to my very own question here:
Some of the suggested libraries up there have issues with installation with Visual Studio 2010, offer practically no instructions for installation with Visual Studio (i.e. FreeImage), or simply have ridiculously messy API's (i.e. libpng).
If you are new to C/C++, please be careful about what library to choose. Even if there are technical forums roaming with gurus who knows all the answers, you are most likely on your own spending days experimenting and piecing up clues that experienced volunteers could've easily answered in 2 sentences (if they bothered).
Now, what works for me is the OpenCV image library (http://opencv.willowgarage.com/), which is introduced by Mister daerty0153 up there. When you go on the website, don't download the superpack from sourceforge. Instead, read the installation instructions (http://opencv.willowgarage.com/wiki/InstallGuide) and choose what platform you are using.
In my case, I use Visual Studio 2010 as my IDE and so this is the actual subpage that is relevant: http://opencv.willowgarage.com/wiki/VisualC%2B%2B
One problem I encountered is letting VS2010 recognize the .dll files and is not remedied by following those instructions. My solution was to copy all of them to my project folder and that solves all the problem. Some suggested it is a VS 2010 bug.
Hope it helps others suffering from the same situation.
I have been trying to generate doxygen documentation for boost, as a way to browse source tree and have man documentation.
However, doxygen has been running for past week or so on IBM power5, and I have no idea how much longer (right now I am on boost_1_43_0/boost/mpl/).
Is there prebuilt doxygen documentation, if not, is there any way to speed up documentation generation without losing cross-referencing in code browser?
I have been using older documentation located on tena-sda, but that is quite old.
thank you
I agree with you. However, doxygen cannot parse the complexity of C++ that Boost utilizes. Best bet is for you to grock (search) the source with a powerful IDE.
Even if it was working using doxygen to browse a source code is not really relevant. Here are two alternatives that I use daily :
grep is your friend ! It is very efficient and fast to find what you want in a source code, even if this one is large
Make development with an IDE that support live parsing like NetBeans, then you will have cross-references inside your whole code, even across libraries (like Boost) that it uses, inside the editor itself.
I'm looking for a wrapper that distills zlib to:
OpenZipFile()
GetItemInfo(n)
UnzipItem(n) // Bonus points for unzipping recursively if item n is a directory.
I see a lot of wrappers around the zlib library on, say, codeproject.com but they are all platform-specific in order to provide the added platform-specific functionality of unzipping to file/memory buffer/pipe.
In boost::iostreams there is the possibility to use zlib, gzip and bzip2 formats.
You find it from http://www.boost.org/
In the zlib source archive, there is a contribution named "minizip".
"minizip" is a set of files you can use to play with .zip files. Basic services you need are already there :
unzOpen
unzLocateFile
unzOpenCurrentFile
unzGetCurrentFileInfo
unzCloseCurrentFile
unzClose
Of course, this is not object oriented (and I'm sure that was not the goal of the creator of minizip), but writing a simple object oriented wrapper should be easy.
firstobject's easy zlib stays cross-platform; it has zlib in a single file easyzlib.c and exposes only ezcompress and ezuncompress functions with the added feature of determining the memory requirement before allocating the exact size.
You could try to grab the code from another FOSS project. ScummVM, for example, has a highly portable Zlib wrapper (implementation, header) with all the functions you need, plus an OO layer for interfacing generically with any other kind of archive.
Maybe that's a good starting point? The wrapper functions are totally standalone and portable (heck, they even work on a Nintendo DS), but the OO layer depends on many custom classes which may be hard to add to your own project.
GZStream is worth a look. This is a nice cross-platform wrapper round ZLib which extend the STL iostream classes.
http://www.cs.unc.edu/Research/compgeom/gzstream/
What is good about this wrapper over some of the others is that if you're working with very large archives you don't need to load the whole dataset into memory.
If you will use minizip -- pay attention, thet version shipped with zlib 1.2.3 has 2GB resulting zip file limitation. IT will produce zip with size >2GB - but you won't be able to open them...
This is an old thread, but I thought I'd throw in Boost's ZLib wrapper:
http://www.boost.org/doc/libs/1_47_0/libs/iostreams/doc/classes/zlib.html
You can check also this C++ Zlib wrapper with auto-detection of input format:
https://github.com/mateidavid/zstr