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I am looking for a C++ library for reading data matrix codes, specifically ECC 200 codes (so not QR codes). I have found libdmtx and zxing. zxing is java, but there seems to be a C++ port. Does anyone have experience with reading ECC 200 codes with these libraries, or possibly with other libraries?
The DM support in the C++ port of ZXing is up to date with the Java (not true of many of the 1D codes). It's not enabled by default in the test apps but is easy to enable (and will be enabled by default in the future.)
I don't have any personal experience with actually using the DM decoder but it is included in the test suites and I believe available in the Android app.
Here's a real answer then.
I have used both libdmtx and libzxing succesfully. Libdmtx was more straightforward, because it's limited to datamatrices. In my experpience the results were, strangely enough, not always deterministic.
Libzxing is fine as well, but when you do real production (millions or readouts) it will crash sometimes due to the fact that memory management is not perfect. It's really good, but not perfect for a real production environment.
Both the libraries, libzxing and libdmtx require you to have the datamatrix deadcenter of the image and quite large. That means you need to do pre-localisation yourself.
I managed to do this by just using image routines and looking for the 'L' shape and then some smartness with a minimal-area squared bounding box, etc etc. Then the decoding and error correciton step itself i used from libzxing, which still isnt perfect.
If you go for a production environment, either do everything yourself within your own contraints, and if you are not comfortable with doing that, use a paid package, which in turn are never perfectly suited for your application and cost money.
The best port of libzxing-cpp is that of user glassenchidna. https://github.com/glassechidna/zxing-cpp
I am currently trying to use libdmtx
http://www.libdmtx.org/
It has support for all kinds of interfaces. It seems to have good reviews here and in other places….
(But I am looking for help on building the utilities :-)
Since no "real" answer was posted to my question, at least no answer from someone with experience with one of these libraries for reading 2D matrix codes, I thought I will post my own experience.
I tried both libraries and both could read codes, but the performance was not good enough for my situations. In my situation the codes are frequently not "perfect", Dots can be missing, have different size, and code can be a bit skewed. Both libraries had problems reading these codes.
At the end I used a commercial (not free) library, Sapera. Sapera was able to read the non-perfect codes much better. I used Sapera because it was used at my company in the past, but it is quite possible that other commercial machine vision libraries (like Halcon) also perform well.
I have exensively used Halcon, including for Decoding DataMatrix. I can tell you that it works really well. Even with distortions caused by, for example, reading off a circular body, or skewed prints, it still is able to read them very well, in a short amount of time.
The only downside, and a big one, is the price. The runtime license is very expensive, and you need a development license before you can purcahse a runtime license, which is even more expensive. Unless you project has enough funds, this might not be an option due to this reason. Good luck!
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Which sector of software industry uses C++?
C++ was for many years the holy grail of mission critical high performance development. However, it seems that for the past 10 years like much of the development world has moved to Java and C#. My quesiton is this, is C++ effectively relegated to embedded systems, OS, Browser and other special purpose development? Should I let this skillset go the way of the VB 6 and other skillsets that are no longer showing the same level of demand and value in the market? I love C++ and would love to update my knowledge in it, but I wouldn't even know where to begin to try to apply it to common business problems today.
Regards.
First of all, I doubt anybody can give a definitive answer -- there's just no way to tell exactly how much any particular language is really used. Nearly anything you can measure is a secondary measurement, such as how many people are advertising jobs using that language. The problem is that this tends to show relatively new languages as dominating to a much greater degree than is real.
That said, my belief is as follows. At one time, C++ was the hot new language on the block, and there was a bubble when it dominated the market. That bubble deflated quite a while ago. Since then, use of C++ has been growing on an absolute basis, but the market has been growing (quite a bit) faster so its shrinking on a relative basis.
There are a couple of reasons this doesn't show up in most secondary measures such as job advertisements though. A couple of the obvious ones include:
Many teams producing C++ have now had years to "settle in", so the turnover rate is relatively low.
It's now well established where it's used, so positions tend to be filled by internal promotions.
There's another effect I almost hesitate to mention, but it's true no matter how little a lot of people like it: there are both programmers and managers who are more excited about "new" than effective. This leads to a large group of wannabes who are constantly on the move to the latest and greatest "technology" (whether that happens to be a language, framework, platform, or whatever). They get a job, loaf (or worse, actually write some code), then move on to their next victim...er...employer. They cause a lot of "churn", and inflate the number of job advertisements, but produce little or nothing of any real value. That group moved from C++ to Java a long time ago, and have long since moved from Java to C# to Ruby on Rails to Hadoop to whatever the managers are excited about this week.
Lest I sound excessively negative, I should add that along the way, a few of them really find something they're good at, and (mostly) tend to stay with that. Unfortunately, for every one who does, there are at least five more new graduates to join the throng...
"C++ effectively relegated to embedded systems, OS, Browser"
"other special purpose development"
You mean 99% of the code people run on a daily basis?
C++ is still heavily used in many mission critical financial applications. For example, most of Bloomberg's platforms are based on C++ with very little front end in other languages. Many investment banks and hedge funds use algorithmic trading systems written completely in C++ (e.g., Tower Research Capital, Knight Capital, etc.).
If you've been out of C++ for a while, you may need to get used to a whole bunch of now-standard libraries. When I was doing most of my C++, STL was fairly new and you either adopted the Microsoft libs or did not. If I went back to C++ now, I'll have to learn all the new libraries to be effective.
I think most of the movement to other languages is related to web development and web-centric development. The main exception to that would be Google, which still primarily use C++ and Python.
C++ is still valuable for many high performance apps. There are other technologies, and depends on the situation different languages are better suited for your needs. But if you want strong performance, good control of what your code is doing, and flexible networking and programming stack, C++ is still a good choice.
A better suggestion is: let the problems come to you and find the language that best suites the situation, rather than take a language and go look for problems.
Still: if you know C++ well, you can learn/program in anything.
To this day, C++ is the only language which is both object oriented and compiled (or at least, which has a mature ecosystem of optimizing compilers). Which leaves it as the sole choice for most large scale, compute-intense projects.
To me the prominent example is games and game engines - these are huuuuuge projects that squeeze machines for milisecond-fractions. MS is trying to get some traction for XNA (a managed game-dev framework - basically a DirectX wrapper ), but most probably would never get any for AAA game productions.
If I take a look at the applications I have installed on the laptop I am writing this message on, I see a lot of C/C++ and few (if any) managed apps. Examples? Google Chrome, Firefox, iTunes, uTorrent, Spotify, Picasa, Google Earth, OpenOffice, Notepad++, IrfanView... this list goes on and on. I write desktop applications for a living, which are installed on thousands of PCs worldwide, and C++ is still my language of choice. The lack of dependencies (WTL is your friend) is a massive plus IMHO (and that of my customers I should add!.) YMMV though - as a seasoned developer I think I am productive enough in C++, but I can't speak for everybody.
It hasn't gone away if you need to do something really, really fast. If "fast enough" is OK, then C# and Java are fine, but if you have a calculation that takes hours or days, or you need something to happen on the microsecond timescale (i.e. high frequency trading) C++ is still the language to use.
More often than not, we get lost in the hype cycle. First there was Java, then came PHP, and currently is Python. But the fact of the matter is development of general purpose desktop application still requires use of libraries like Carbon/Cocoa for mac, GTK/QT for Linux, MFC for Windows. All of which are C/C++ based. So are most applications written for these platforms. So calling C++ as being relegated to embedded is not right, although yeah its being extensively used now, unlike earlier when it was just assembly or C at the max. In my opinion, if you want a high performance application with great looking GUI, it still has to be done in C/C++.
Different languages are prevalent in different domains. It is interesting that you think it might be rendered unimportant by being relegated to embedded systems when in fact that is where most software development occurs; at least in terms of number of projects/products.
There are many ways of measuring, and a number of them are presented here: http://langpop.com/. The evidence suggests that C++ remains important.
I'm not sure whether the gaming industry falls under "general purpose development", but if you want to develop anything that you intend to get working on more than a single console, C++ is what's for lunch. While many gaming and 3D libraries have extensions for other languages, they -all- have extensions for C/C++.
C++ is still used everywhere you want the best performance. Its major advantage is that you can use literally for everything. In addition to what other people have said you can also use it to power websites, for instance OkCupid uses it almost exclusively.
As the recent Hip Hop of Facebook shows, in the end, if you can afford it (ie. you have a large and competent team) you can always gains something using it. Then it also a matter of scale, other than industry.
C++ is still very popular. For instance, combined with Qt it is often used.
C++ is usually used for systems work, generally defined as software where the UI is not central, not application work -- where the UI is central. So, for general business use it's probably not very interesting and those problems are better solved with a higher level language. However, there will always be low level systems work to be done, and C or C++ is the practical answer for those problems right now.
As a general development language? Well, it depends on your industry, but I've worked in two different industries and there is always plenty of C++ work:
Telecoms
Embedded devices often use C and C++ for core services
Network equipment, often very complex, heavily utilize C++
Software apps that work with hardware will often be written in C++
Financial Services
Trade Execution systems are often in C++. You cannot have your garbage collection kick in when you're executing an order for a customer.
Algorithmic and high-frequency trading systems are usually in C++
General trading systems that do not have strict speed requirements seem to be in C++ and Java, with C# starting to show up as well.
Administrative applications tends to be written in Java, VB, or C# these days
Recently there is a trend towards functional languages for quantitative analysis, so F# and Haskell are starting to appear, and SAS and Matlab are always common too
I read somewhere that Nyse/Euronext uses Java, but that they disable the garbage collector and run on servers with insane amounts of memory.
I am writing a piece of software in C++ which is targeted at a market in which software is traditionally heavily cracked (or at least, attempted to be). I realise that nothing can be completely protected, however I feel that trying would be a good idea and also I think some of the specifics of the situation that I'm in might be helpful.
Firstly, it would not be annoying to the user that they must have an internet connection to use the software. I hate it when games etc. do this too, but the software requires an internet connection to function anyway due to its purpose, so this wouldn't hinder a normal user.
Secondly, it depends fairly heavily on external scripts written by me and/or supplied by third-parties, so I can have these stored on some website somewhere meaning that people who crack the software will have to also track down new copies of the scripts, which may annoy them into becoming legit.
Thirdly, new versions will, by definition due to what the app does, have to be released very often, weekly or every two weeks max. The program will obviously have an autoupdater, but since I am churning out (required to function) updates so often, any sort of key-based encryption or whatever could possibly have the keys/method change every update, and I am capable of breaking existing cracks when they do happen.
Does anyone know of any available solutions or techniques I could implement which fit the bill?
If you application is doing some sort of data processing or analysis, you can protect it by putting that part into a web service (maybe in a cloud) that your client application connects and authenticate to and then receive results from. So even if your client application is reversed engineered, it would be missing that important piece of processing.
If your application is web based, you get the same effect too.
I've previously used CrypKey successfully.
I'm going to guess that older copies of the software are far less useful than the latest copy.
If that's the case, then you already have a powerful anti-cracker technology in place: your update mechanism. When you become aware of a hacked version of your software, then you can immediately check for it, and cause trouble for users of the hacked software.
As a hobby project I am trying to create a ROM (Diku-Merc based) derivative. (Now defunct) I would appreciate it if anybody has done something similar and has some useful resources to share or tips to offer. I'm finding that a lot the resources such as mailing lists are no longer active and many links are dead.
I've picked ROM because that is what I am familiar as a player, but the source is more complicated than anything I have come across and I wouldn't mind picking a code base that was easier to understand. Any recommendations before I dive in in earnest would also be appreciated.
As for mudding communities in general I don't know of much beyond the mud connector because I've always been in more of a user/player role than developer. A forgiving and active place where I can get answers to my questions is what I value most.
After extensive research I've decided to go with a tba code base. I may elaborate later but very broadly
Coding experience is more important than experience as a player and this has convinced me to abandon my roots. I wanted a well documented, reasonably modern, managable code base undergoing active development and this seems to fit the bill.
Anyways muds are truly a labour of love and you have to have a few screws loose if you plan to run one. Moreover the glory days have passed (it seems like there many muds shut down en masse around 2000) and in my opinion the community is largely inactive and fragmented. An exerpt from from some of the tba docs sums this up nicely:
So, you're sure you want to run your own MUD? If you're already an
old hand at playing MUDs and you've
decided you want to start one of your
own, here is our advice: sleep on it,
try several other MUDs first. Work
your way up to an admin position and
see what running a MUD is really
about. It is not all fun and games.
You actually have to deal with people,
you have to babysit the players, and
be constantly nagged about things you
need to do or change. Running a MUD is
extremely time consuming if you do it
well, if you are not going to do it
well then don't bother. Just playing
MUDs is masochistic enough, isn't
it? Or are you trying to shave that
extra point off your GPA, jump down
that one last notch on your next job
evaluation, or get rid of that pesky
Significant Other for good? If you
think silly distractions like having
friends and seeing daylight are
preventing you from realizing your
full potential in the MUD world, being
a MUD Administrator is the job for
you.
Anyways I don't have any high hopes for success, but this is something I will find interesting, improve my code-fu and will keep me busy for many years to come :D
There is no active ROM developer mailing list, so tba definitely is a better choice. There was some effort to clean up ROM with the RaM project.
Dead Souls sees active development as well (the main dev is a hero in my eyes for the amount of work he produces).
I would not recommend MUCK as the userbase is rather small. However that is not to say there isn't good work being done -- look up the user Valente on the code subforum of the wora.netlosers.com forum, as he's probably one of the foremost MUCK developers at the moment.
However if you thought that ROM was complicated I should caution you about tackling an established/canon codebase for any purpose other than getting a familiarity with mud servers. For actual development you may be better off with a barebones codebase such as NakedMUD (C/Python) or even something slimmer than that such as Socketmud (ports in many languages).
There are of course dozens of mud servers you can look at; all will be educational in some manner, but in the beginning stages it won't be obvious what is good practice and what is not. You may want to look up ColdC (similar to LP) and TeensyMUD (Ruby) to study. The author of Teensy, Jon Lambert, has a useful developer site up at http://sourcery.dyndns.org/.
However you'll find very experienced ROM and tba (i.e., Circle) developers at MudBytes, and I'll second Sam to say that is the most active mud developer site currently. It's a little surprising but in the last year there has been a significant growth in activity at MB. I think people are coming in from the fold so to speak and gathering at MB. There also is a good-sized code repository at MB as well.
Your other options are The Mudconnector which you already know, Top Mud Sites which has a somewhat smaller crowd of mostly developers (typically of established and long-running muds), and Mudlab, which is much quieter but usually with a good signal to noise ratio. MudGamers is an interesting new site with a fairly quiet forum, but a new approach to creating a more contemporary-looking portal for playing muds.
Not to be overlooked is the archive for the old mud-dev mailing list. There is a staggering amount of information to be gleaned there. The raw archive can be found at muddev.wishes.net/. Richard Tew also has done some noble work in combing through old usenet archives to find valuable mud development related threads, which you can find through his mud tag at posted-stuff.blogspot.com/search/label/mud.
I should note that many muds use the IMC chat network to link muds (MB has a portal to this as well on the front page of their site). Once your mud is running it can be useful to get on IMC if you're in need of real-time chat to fix a problem (of course, there are many IMC channels and you'll want to choose which one you use prudently).
Despite the fact that muds today are niche at best and unheard of at worst, there is no shortage of new muds in development. They offer a design and programming challenge that is still accessible to the solo developer, unlike any graphical game of equal size or complexity.
Furthermore you shouldn't be discouraged if it feels like you'll never release a playable game. Like many larger projects you may start and abandon it many times over, but you'll be building proficiencies across a wide spectrum of programming skillsets and applications -- not many projects will allow you to take such a whole systems approach. Good luck!
An active community seems to be around for the Dead Souls MUDlib
http://en.wikipedia.org/wiki/Dead_Souls_MUDlib
I was an old player of Nightmare LPMud which sadly disappeared. I'm not much in for the coding of these MUDs, but I have been following this community loosely just due to so many positive MUDding memories.
Take a look at Nameless MUCK. It's a solid piece of software.
First concentrate on getting or finding a solid Telnet Socket library going, this is generally the main protocol for a MUD.
Next, create a FULL list of features that you want to implement, you should probably get some sort of feature or bug tracking system setup (even if it is a spreadsheet). Then prioritize the features based on dependencies of other systems.
Check out http://www.gamasutra.com for some architectural discussions on creating games in general, creating basic AI, character systems, and multi-player games.
Once you understand the theory, it is just a butt load of programming to build in everything you want to support.
I'd make the MUD engine abstract enough to run behind both a terminal client, a web-based Ajax client, and maybe stand-alone clients - i.e., don't tie the front end in with the actual game logic. I'm not averse to a MUD actually using a decent font for the text, and real graphics (as interstitials or to make notes on the bulletin board look like notes, etc), not in place of the text based interface) where necessary instead of ASCII, etc.
You might also want to have some MUD script file converters into your own format, so that you don't have to spend ages creating zones.
I find the problem with MUDs is that there is too much emphasis on killing NPCs, and not many puzzles or other interesting aspects. So a more interesting, story-oriented (possibly to the extend of sharding zones for single-player or single-team use) engine could be a nice feature to have.
I will take this opportunity to recommend MudBytes, which is probably the most active MUD developer site available right now.
Last term (August - December 2008) me and some class mates wrote an application in C++. Nothing spectacular, it is an ORM for Sqlite3. We implemented some stuff like reflection to make it work and release the end user from the ugly stuff. Personally, i think we made a nice job, and that our ORM could actually be useful for someone (even though its writen specifically for Sqlite3, its easily adaptable for oter databases).
Consequently, i`ve come to the conclusion that it should be published somewhere (sourceforge most likely) as an open source project. But, as it was a term project, there are some things that need to be addresesed before doing that. Namely, it has some memory leaks that should be fixed, and some parts of the code could be refactored to make everyone´s life easier in the future.
I would like to know more experienced C++ programmers opinion on some issues:
Is it worth rewriting some parts to
apply new techonologies (for example,
boost).
Should our ORM be adapted to latest
C++ standard? Is there any benefit in
doing this?
How will we know when our code is
ready for release?
What are the chances that this ORM
will be forgotten into the mists of
the internet? (i.e is it worth
publishing it beyond personal pride
as a programmer?)
Right now i can`t think of many more questions, but i would like to read on similar experiences.
EDIT: I should probably translate my code + comments to english right? (self question)
Thanks in advance.
I guess I am "more experienced" with regard to your particular question. I co-developed an open source web application language & template system a lot like ColdFusion back in the early days of web design before Java or ASP were around. You can still see it at http://www.steelblue.com/ if you are interested. It's still used at the company I was at when it was developed, but I don't think anywhere else.
What I found is that unless you are already well connected and people are watching what you are doing, getting people to use your open source code is just about as hard as selling somone your closed source program. You really need to advocate for your project and it should have some kind of unique selling proposition that distinguishes it from the compitition.
So, that's the unsolicited advice. Here are some specific answers to the questions you had...all purely my opinion, of course.
I wouldn't rewrite any code unless you have a featuer you want to put in. That feature might be compatibility with a specific platforms or compilers. It might be to support a new db datatype or smarter indicies or whatever. If you are going to put some more serious work into the applicaiton, think about a roadmap of what you can realistically accomplish in the next iteration and what choices will make the app the "most better" at the end of your cycle.
Release the code as soon as it is usable for a specific purpose, any purpose. Two reasons. First off, there might be someone who wants it for that purpose right now. If it's not available, they will use something else. Also, if it's open source, they might contribute back to the project. Second, the sooner you find out how much people want to use the code, the better. Either it will be more popular than you expect and you can get excited about continuing the development....or....you will find that no one is even visiting your web page to see what you've got. In either case, better to know sooner than later what people really want from your project so you can take that into account when planning new releases.
About the "forgotten into the mists." I think most projects are. I don't want to be a downer, but looking at Wikipedia, there were 5 C++ ORM tools popular enough to get mention and they were all open source. As I said above, unless you can sell your idea to people, they are going to go with another proven open source solution. For someone to choose you over them, three things have to happen: 1. They need a feature you have that the others don't. 2. They find your project web site and it demonstrates the superiority of your code. 3. They trust your code enough to give it a shot.
On the other hand, if you are in this for the long haul and want to continue development thigns get easier over time. Eventually the project will get all the basics covered and you can start developing those new featuers that aren't in the other solutions. Also, the longer you are in active development the more trustworthy the project will seem. Finally, you will get more experience in the nitch. 2 years from now you will be better positioned to say where your effort will have the most impact on bettering the project.
A final thought: If you are enjoying it, learning from it, and it's not getting in the way of you keeping food on the table, it's a good use of your time.
Good luck!
-Al
Regarding the open source part:
If you really want to make it an open source project, you really should publish it regardless of it's current state - fully working and debugged - or half working and full of memory leaks.
Just, if it's state is bad, make sure to document it, and give it a suitable version number (less than one?). then others may view your code, suggest improving, join your team, etc...
My--rather random--thoughts on the matter (in the order I think is most important):
How will we know when our code is ready for release?
Like Liran Orevi said: if you're going open source release early. Document it reasonable well, and take the time to provide a road map of planned or hoped for future improvements (these are a invitation for people to help you, so note which ones have no one working on them).
Is it worth rewriting some parts to apply new technologies (for example, boost).
Should our ORM be adapted to latest C++ standard? Is there any benefit in doing this?
SQLite relies on a fairly limited base. Maybe you don't want your tool to demand a much heavier environment. If the code in not currently a tangled and unmaintainable mess, you might want to avoid boost and newest frills. Once you have a stable release (1.0 at least) you can starting thinking about the improvements that can be made for version 2.
What are the chances that this ORM will be forgotten into the mists of the internet? (i.e is it worth publishing it beyond personal pride as a programmer?)
Most things end up in the big /dev/null in the sky, and there is only one way to find out... If it goes anywhere at all, you win. If it doesn't it was a modest investment, and maybe you learned something while you were at it.