Is it possible to call a C/C++/Python/Java function that makes an HTTP request inside of a Verilog module?
Yes, do some searching for 'DPI' or 'PLI'. If you have a SystemVerilog capable simulator the DPI solution is a lot less overhead. Basically the Verilog end of it will be:
import "DPI" function void do_http(...)
Where you can then call do_http within your Verilog like a normal task or function and you pass the .c file that implements do_http on the command line along with the rest of your sources. This of course is assuming that you're using a commercial Verilog simulator. I don't think Icarus supports DPI yet (could be wrong).
Using VPI is a more portable but takes significantly more coding to put together. I encourage you to research that one on your own if that's what you need.
Related
Is it possible to convert a Sketch file to an SVG without actually having Sketch or DrawIt? I know it's theoretically possible since they're both vector, but I use Windows and Linux, so I don't have a Mac to open the files with.
Figma is currently free for anyone to sign up and supports both Sketch import and SVG export. It's a fully-featured design tool that's browser-based so it should work on all three major platforms (OS X, Windows, and Linux). File import from Sketch isn't a perfect 1-to-1 mapping with Figma because both apps have slightly different feature sets, but it should get you 99% of the way there.
There's no "magic" about "Sketch using a lot of technology that is exclusive to OS X" or not. That statement on Sketch makers' website is in the context that they do not intend to make Sketch app available on linux and on windows.
The real problem you have is as follows:-
The sketch file is an sqlite3 file and in it there are (currently at this time of writing) two tables, meta and payload. The payload table is a single key-value store, storing main and and BLOB value. So that's where you get stuck - you will have to figure out how to reverse engineer the BLOB if you do not have a Sketch program.
On the other hand, if you do have a Sketch program, you do not need to reverse engineer anything, you can query information from your Sketch file using Sketch Plugin APIs, which are well documented here - http://bohemiancoding.com/sketch/support/developer/ - which will allow you to automate a lot of the tasks if you have a complicated design workflow. http://zeplin.io is an example of a simple Sketch plugin that pulls out relevant "spec" information for a developer from a designer-created sketch artboard.
But back to your original question, Sketch itself allows you to export SVG files but that assumes you have the Sketch app. Long story short, unless you reverse engineer the BLOB binary in the sketch file (or use a tool that someone else created that can), you can't programmatically translate sketch files into SVG files without having a Sketch app.
Currently I am calling an R script from C++ in the following way:
system("PATH C:\\Program Files\\R\\R-3.0.1\\bin\\x64");
system("RScript CommandTest.R");
Where CommandTest.R is my script.
This works, but is slow, since I need a particular package and this method makes the package load on every call.
Is there a way to load the package once and then keep that instance of Rscript open so that I can continue to make calls to it without having to reload the package every time?
PS: I know that the 'better' method is probably to go with Rcpp/Rinside, and I will go down that route if necessary, but I thought it'd be worth asking if there's an easy way to do what I need without it.
It seems like the Rserve package is what you seek. Basically it keeps open a "server" which can be asked to evaluate expressions.
It has options for Java, C++ and communication between one R session and another.
In the documentation, you might want to look at run.Rserve and self.ctrlEval
I'm not aware of a solution to keeping R permanently open, but you can speed up startup by calling R with the --vanilla option. (See Appendix B.1 of Intro to R for more options.)
You could also try accessing the functions using :: to save completely loading the package. (Try profiling to see if that really saves you much time. Is the package load actually the slow part of your analysis?)
I am working on a multinational project where target audience for logs might be from two nationalities. Therefore it is becoming important to log in more than one language , I am thinking about writing to 2 different log folders based on language every time I am logging something, but I am also wondering if there's some out of the box functionality that is coming along with logging frameworks like log4cpp?
As other commenters have mentioned, it sounds like you are going down the wrong track by looking to do multilingual logging.
My recommendation would be to use English (which is the standard for technical information, and which I guess is the language you know best) and to make sure that the language you use is clear, grammatically correct and unambiguous. Then if one of the technicians cannot understand it, they can very easily and efficiently run it through a machine translation engine such as Google Translate. Or indeed they could process the logs and run everything through Google Translate to append translated text, particularly if you annotate the logs to mark the language content.
Assuming that the input language is well-written, machine transation usually gives a good result which the end user can understand. If the message isn't clear, has typos or abbreviations, then that's where machine translation fails spectacularly.
Writing log naturally brings down the speed of execution due to file open, seek and write operations involved as part of it.
This is one primary reason why many developer and architects suggest to write log at different levels.Increasing the depth of log entries as level increases to trace down the problems better. At higher level, you will notice that your process speed drops due to more log entries getting generated.
Rather suggest you to use services that can translate from one language to other.
I'm sure there are libraries free or paid which does this translation. You can create a small utility program that runs in the background and does this conversion during process idle time.
Well one suggestion is you can use a different process/thread which listens for your log messages, which you can log it from there ..
This reduces I/O logging time in your main process/thread and you can make all changes related to Logging language over there..
For multi - Lingual support I think you can try writing with widechar string .. though I am not sure..
the best approaches for logging localization using c++
Install Qt 4 and use QObject::tr/ tr() macro for strings. Write strings in whatever language you want. Hire/Get a translator to localize strings using QT Linguist.
Please note that perfect translation is impossible, so there will be many "amusing" misunderstandings, even if your translator is a genius. So it might be a better idea to select main language for programming team.
--EDIT--
Didn't notice this part before:
in more than one language
One way to approach it is to implement log reader. Instead of writing plaintext messages, you could dump message ids (generated by some kind of macros) and string arguments if strings are formatted. "Log reader" will allow user to select desired language while viewing log file, and translate messages based on their ids/arguments using mechanism similar to QTranslator. The good thing about this approach is that you'll be able to add more languages later - so it'll be possible to retranslate old logs. The bad thing is that this format will be harder to read for "normal human", although you can add plaintext messages in addition to message ids and arguments and you'll need to write log viewer.
Qt 4 has most of this framework implemented (there are routines for dumping variants into text/data streams, and so on) along with translation tool. See QTranslator documentation and Linguist manual for more info.
I want to experiment a bit with C++ as a server side language. I'm not looking for a framework, and simply want to achieve a silly old "Hello World" webapp using C++.
Is there an Apache HTTP server module that I can install?
If i can do the PHP equivalent of :
<?php
$personName = "Peter Pan";
echo "Hello " . $personName;
I'd be most thrilled! Thanks in advance!
cgi would do this. Just have your C++ app spit its output to stdout and your mod_cgi will handle it
You might want to have a look at http://www.webtoolkit.eu/wt or www.tntnet.org instead.
"mod_c++" doesn't make sense; Once you're talking about compiled programs, Apache doesn't care what language the binary comes from. mod_cgi allows Apache to invoke such a binary (regardless of it's source language) in response to HTTP requests. Read more here:
http://library.thinkquest.org/16728/content/cgi/cplusplus.html
Suppose for the moment the OP wanted something that was "like mod_php, mod_perl". Given the right configuration, it would be monumentally easy for the "mod_c++" to look at the source files, and compiled files and decide whether it had to do a "one off" compilation task. In fact this is how make works.
I know the OP probably didn't mean that it had to be "interpreted", but it's certainly not impossible to allow apache to compile cpp files on the fly if needed [this is how jsp works, btw].
I did create a mod_cpp once. It basically was written in c, but loaded a .so which was in turn written in C++.
Its performance was really good, but lacked a lot of things that we take for granted in things like PHP (sessions, HTML un/escaping, etc). It did use a template engine to separate the HTML from the C++.
I tell you, the initial set-up was a lot of work (the mod_cpp part); after that, it was kinda easy to write the .so's. I even tried to create an sf.net project to open-source it, but I never got around to actually porting it :-(
In summary: I did not find anything like that on the net, did it myself and found out to be a lot more work then I anticipated, but the result was very cool! This helped me a lot: Apache Modules
I'm not saying there is no such thing, but if there is it would be monumentally inefficient. C++ is a compiled language, not an interpretive one, so the putative Apache C++ module would have to invoke the C++ compiler to compile the code before executing it. This would be very, very slow, apart from other problems.
I'm trying to write a chat client for a popular network. The original client is proprietary, and is about 15 GB larger than I would like. (To be fair, others call it a game.)
There is absolutely no documentation available for the protocol on the internet, and most search results only come back with the client's scripting interface. I can understand that, since used in the wrong way, it could lead to ruining other people's experience.
I've downloaded the source code of a couple of alternative servers, including the one I want to connect to, but those
contain no documentation other than install instructions
are poorly commented (I did a superficial browsing)
are HUGE (the src folder of the target server contains 12 MB worth of .cpp and .h files), and grep didn't find anything related
I've also tried searching their forums and contacting the maintainers of the server, but so far, no luck.
Packet sniffing isn't likely to help, as the protocol relies heavily on encryption.
At this point, all my hope is my ability to chew through an ungodly amount of code. How do I start?
Edit: A related question.
If your original code is encrypted with some well known library like OpenSSL or Ctypto++ it might be useful to write your wrapper for the main entry points of these libraries, then delagating the call to the actual library. If you make such substitution and build the project successfully, you will be able to trace everything which goes out in the plain text way.
If your project is not using third party encryption libs, hopefully it is still possible to substitute the encryption routines with some wrappers which trace their input and then delegate encryption to the actual code.
Your bet is that usually enctyption is implemented in separate, relatively small number of source files so that should be easier for you to track input/output in these files.
Good luck!
I'd say
find the command that is used to send data through the socket (the call depends on the network library)
find references of this command and unroll from there. If you can modify-recompile the server code, it might help.
On the way, you will be able to log decrypted (or, more likely, not yet encrypted) network activity.
IMO, the best answer is to read the source code of the alternative server. Try using a good C++ IDE to help you. It will make a lot of difference.
It is likely that the protocol related material you need to understand will be limited to a subset of the files. These will contain references to network sockets and things. Start from there and work outwards as far as you need to.
A viable approach is to tackle this as a crypto challenge. That makes it easy, because you control so much.
For instance, you can use a current client to send a known message to the server, and then check server memory for that string. Once you've found out in which object the string ends, it also becomes possible to trace its ancestry through the code. Set a breakpoint on any non-const method of the object, and find the stacktraces. This gives you a live view of how messages arrive at the server, and a list of core functions essential to message processing. You can next find related functions (caller/callee of the functions on your list).