We need to compress and send the data from each of the endpoint client (IOS/Android/Windows Classic) and decompress it in serve end using .NET.
Is there any open source common library for compress/decompress which can be used in this scenario (common X platform).
Pl advise.
Just about any programming platform developed it the past 20 years supports zlib out of the box. Since they generally all incorporate the same free library, the data they generate is interoperable.
Look through API documentation for keywords like "zlib", "gzip", or "deflate". For example, in Android, check out Deflater and DeflaterOutputStream which implement zlib.
Related
I've been wanting to play around with audio parsing for a while now but I haven't really been able to find the correct library for what I want to do.
I basically just want to parse through a sound file and get amplitudes/frequencies and other relevant information at certain times during the song (like every 10 ms or so) so I can graph the data for example where the song speeds up a lot and where it gets really loud.
I've looked at OpenAL quite a bit but it doesn't look like it provides this ability, other than that I have not had much luck with finding out where to start. If anyone has done this or used a library which can do this a point in the right direction would be greatly appreciated. Thanks!
For parsing and decoding audio files I had good results with libsndfile, which runs on Windows/OSX/Linux and is open source (LGPL license). This library does not support mp3 (the author wants to avoid licensing issues), but it does support FLAC and Ogg/Vorbis.
If working with closed source libraries is not a problem for you, then an interesting option could be the Quicktime SDK from Apple. This SDK is available for OSX and Windows and is free for registered developers (you can register as an Apple developer for free as well). With the QT SDK you can parse all the file formats that the Quicktime Player supports, and that includes .mp3. The SDK gives you access to all the codecs installed by QuickTime, so you can read .mp3 files and have them decoded to PCM on the fly. Note that to use this SDK you have to have the free QuickTime Player installed.
As far as signal processing libraries I honestly can't recommend any, as I have written my own functions (for speech recognition, in case you are curious). There are a few open source projects that seem interesting listed in this page.
I recommend that you start simple, for example working on analyzing amplitude data, which is readily available from the PCM samples without having to do any processing. Being able to visualize the data is very useful, I have found Audacity to be an excellent visualization tool, and since it is open source you can build your own tests inside it.
Good luck!
Similar: Does anyone know of a C/C++ Unix QR-Code library?
I tried libqrencode but apparently it's only able to generate a QR-Code. However, I need a library that reads the data from a photo of a printed QR-Code.
It must be a C, C++ or Objective-C library and it has to compile on BSD systems. On my platform, Java and .NET are not available.
What libraries can I use?
Thanks.
Try using libdecodeqr , it doesn't seem to be updated for over a year but a Google search reveals that it still works.
zxing (http://code.google.com/p/zxing/) is probably the most well-known and used in a number of barcode/qr-code apps. The original/primary code is Java but it includes a C++ port that is pretty actively maintained, particularly for QR codes.
The C++ library does not (currently) have an encoder, but it sounds like you want a decoder.
we have a C++ MFC application and C# Web Service. They are communicating over HTTP, but as they are exchanging text data, compression will help a lot. But for some reasons, we can't use an external library.
We basically need to compress a byte array on one side and decompress it on the other side.
What should we use to compress our data? The best scenario would be if there is something in MFC/win32 api. Or is there some simplistic code with at most LGPL license that we could integrate into our project?
As has already been said, the zlib is probably what you are looking for.
There are several algorithms within:
The deflate and inflate pair
zlib itself
lzo
The simpler is probably lzo (I advise to pass the uncompressed size on the side), but zlib isn't very complicated either and the compression rate can be parameterized (speed / size trade off) which can be a plus depending on your constraints.
For XML data (since you were speaking of web services), LZO gave me a ~4x compression factor.
Can't you just switch on HTTP compression? http://en.wikipedia.org/wiki/HTTP_compression
zlib has a very liberal license.
I need to write a program that displays a PDF which a third-party supplies. I need to insert text data in to the form before displaying it to the user. I do have the option to convert the PDF in to another format, but it has to look exactly like the original PDF. C++ is the preferred language of choice, but other languages can be investigated (e.g. C#). It need to work on a Windows desktop machine.
What libraries, tools, strategies, or other programming languages do you suggest investigate to accomplish this task? Are there any online examples you could direct me to.
Thank-you in advance.
What about PoDoFo:
The PoDoFo library is a free, portable
C++ library which includes classes to
parse PDF files and modify their
contents into memory. The changes can
be written back to disk easily. The
parser can also be used to extract
information from a PDF file (for
example the parser could be used in a
PDF viewer). Besides parsing PoDoFo
includes also very simple classes to
create your own PDF files. All classes
are documented so it is easy to start
writing your own application using
PoDoFo.
iTextSharp is a free library that you can use in .Net applications. Take a look at the iText page - that is for the iText project, which is a Java library. iTextSharp is part of that project, and is a port to C# and .Net.
Consider Python It have a lot PDF librarys (both creating and extracting) eg:
http://pypi.python.org/pypi/pdfsplit/0.4.2
http://pypi.python.org/pypi/JagPDF/1.4.0
http://pypi.python.org/pypi/pdfminer/20091129
http://pypi.python.org/pypi/podofo/0.0.1
http://pypi.python.org/pypi/pyFPDF/1.52
There are also good tools for using C/C++ code in Python and to create .exe form Python scripts. If you decide to use different language consider Python as prototyping language!
I'm using wxWidgets to write cross-plafrom applications. In one of applications I need to be able to load data from Microsoft Excel (.xls) files, but I need this to work on Linux as well, so I assume I cannot use OLE or whatever technology is available on Windows.
I see that there are many open source programs that can read excel files (OpenOffice, KOffice, etc.), so I wonder if there is some library that I could use?
Excel files it needs to support are very simple, straight tabular data. I don't need to extract any formatting except column/row position and the data itself.
Suggestedd reference: What is a simple and reliable C library for working with Excel files?
I came across other libraries (chicago on sf.net, xlsLib) but they seem to be outdated.
jrh
I can say that I know of a wxWidgets application that reads Excel .xls and .xlsx files on any platform. For the .xlsx files we used an XML parser and zip stream reader and grab the data we need, pretty easy to get going. For the .xls files we used: ExcelFormat, which works well and we found the author to be very generous with his support.
Maybe just some encouragement to give it a go? It was a couple of days work to get working.
Maybe http://www.libxl.com/ can help ?
I think that it is not something easy to do. xls files are quite complex and it is a proprietary format.
Maybe this is a stupid idea but why don't you upload and access your doc with Google docs. There are some apis to access your doc.
2 potential problems:
- Your app needs internet access
- Currently there is no C++ api.
But there are api for several languages including python see http://code.google.com/intl/fr/apis/gdata/articles/python_client_lib.html