Search Results

Search found 11972 results on 479 pages for 'writing'.

Page 84/479 | < Previous Page | 80 81 82 83 84 85 86 87 88 89 90 91  | Next Page >

• How should I plan the inheritance structure for my game?

  - by Eric Thoma

  I am trying to write a platform shooter in C++ with a really good class structure for robustness. The game itself is secondary; it is the learning process of writing it that is primary. I am implementing an inheritance tree for all of the objects in my game, but I find myself unsure on some decisions. One specific issue that it bugging me is this: I have an Actor that is simply defined as anything in the game world. Under Actor is Character. Both of these classes are abstract. Under Character is the Philosopher, who is the main character that the user commands. Also under Character is NPC, which uses an AI module with stock routines for friendly, enemy and (maybe) neutral alignments. So under NPC I want to have three subclasses: FriendlyNPC, EnemyNPC and NeutralNPC. These classes are not abstract, and will often be subclassed in order to make different types of NPC's, like Engineer, Scientist and the most evil Programmer. Still, if I want to implement a generic NPC named Kevin, it would nice to be able to put him in without making a new class for him. I could just instantiate a FriendlyNPC and pass some values for the AI machine and for the dialogue; that would be ideal. But what if Kevin is the one benevolent Programmer in the whole world? Now we must make a class for him (but what should it be called?). Now we have a character that should inherit from Programmer (as Kevin has all the same abilities but just uses the friendly AI functions) but also should inherit from FriendlyNPC. Programmer and FriendlyNPC branched away from each other on the inheritance tree, so inheriting from both of them would have conflicts, because some of the same functions have been implemented in different ways on the two of them. 1) Is there a better way to order these classes to avoid these conflicts? Having three subclasses; Friendly, Enemy and Neutral; from each type of NPC; Engineer, Scientist, and Programmer; would amount to a huge number of classes. I would share specific implementation details, but I am writing the game slowly, piece by piece, and so I haven't implemented past Character yet. 2) Is there a place where I can learn these programming paradigms? I am already trying to take advantage of some good design patterns, like MVC architecture and Mediator objects. The whole point of this project is to write something in good style. It is difficult to tell what should become a subclass and what should become a state (i.e. Friendly boolean v. Friendly class). Having many states slows down code with if statements and makes classes long and unwieldy. On the other hand, having a class for everything isn't practical. 3) Are there good rules of thumb or resources to learn more about this? 4) Finally, where does templating come in to this? How should I coordinate templates into my class structure? I have never actually taken advantage of templating honestly, but I hear that it increases modularity, which means good code.

  Read the article

• Deliberate Practice

  - by Jeff Foster

  It’s easy to assume, as software engineers, that there is little need to “practice” writing code. After all, we write code all day long! Just by writing a little each day, we’re constantly learning and getting better, right? Unfortunately, that’s just not true. Of course, developers do improve with experience. Each time we encounter a problem we’re more likely to avoid it next time. If we’re in a team that deploys software early and often, we hone and improve the deployment process each time we practice it. However, not all practice makes perfect. To develop true expertise requires a particular type of practice, deliberate practice, the only goal of which is to make us better programmers. Everyday software development has other constraints and goals, not least the pressure to deliver. We rarely get the chance in the course of a “sprint” to experiment with potential solutions that are outside our current comfort zone. However, if we believe that software is a craft then it’s our duty to strive continuously to raise the standard of software development. This requires specific and sustained efforts to get better at something we currently can’t do well (from Harvard Business Review July/August 2007). One interesting way to introduce deliberate practice, in a sustainable way, is the code kata. The term kata derives from martial arts and refers to a set of movements practiced either solo or in pairs. One of the better-known examples is the Bowling Game kata by Bob Martin, the goal of which is simply to write some code to do the scoring for 10-pin bowling. It sounds too easy, right? What could we possibly learn from such a simple example? Trust me, though, that it’s not as simple as five minutes of typing and a solution. Of course, we can reach a solution in a short time, but the important thing about code katas is that we explore each technique fully and in a controlled way. We tackle the same problem multiple times, using different techniques and making different decisions, understanding the ramifications of each one, and exploring edge cases. The short feedback loop optimizes opportunities to learn. Another good example is Conway’s Game of Life. It’s a simple problem to solve, but try solving it in a functional style. If you’re used to mutability, solving the problem without mutating state will push you outside of your comfort zone. Similarly, if you try to solve it with the focus of “tell-don’t-ask“, how will the responsibilities of each object change? As software engineers, we don’t get enough opportunities to explore new ideas. In the middle of a development cycle, we can’t suddenly start experimenting on the team’s code base. Code katas offer an opportunity to explore new techniques in a safe environment. If you’re still skeptical, my challenge to you is simply to try it out. Convince a willing colleague to pair with you and work through a kata or two. It only takes an hour and I’m willing to bet you learn a few new things each time. The next step is to make it a sustainable team practice. Start with an hour every Friday afternoon (after all who wants to commit code to production just before they leave for the weekend?) for month and see how that works out. Finally, consider signing up for the Global Day of Code Retreat. It’s like a daylong code kata, it’s on December 8th and there’s probably an event in your area!

  Read the article

• News From EAP Testing

  - by Fatherjack

  There is a phrase that goes something like “Watch the pennies and the pounds/dollars will take care of themselves”, meaning that if you pay attention to the small things then the larger things are going to fare well too. I am lucky enough to be a Friend of Red Gate and once in a while I get told about new features in their tools and have a test copy of the software to trial. I got one of those emails a week or so ago and I have been exploring the SQL Prompt 6 EAP since then. One really useful feature of long standing in SQL Prompt is the idea of a code snippet that is automatically pasted into the SSMS editor when you type a few key letters. For example I can type “ssf” and then press the tab key and the text is expanded to SELECT * FROM. There are lots of these combinations and it is possible to create your own really easily. To create your own you use the Snippet Manager interface to define the shortcut letters and the code that you want to have put in their place. Let’s look at an example. Say I am writing a blog about something and want to have the demo code create a temporary table. It might looks like this; The first time you run the code everything is fine, a lovely set of dates fill the results grid but run it a second time and this happens.   Yep, we didn’t destroy the temporary table so the CREATE statement fails when it finds the table already exists. No matter, I have a snippet created that takes care of this.   Nothing too technical here but you will see that in the Code section there is $CURSOR$, this isn’t a TSQL keyword but a marker for SQL Prompt to place the cursor in that position when the Code is pasted into the SSMS Editor. I just place my cursor above the CREATE statement and type “ifobj” – the shortcut for my code to DROP the temporary table – which has been defined in the Snippet Manager as below. This means I am right-away ready to type the name of the offending table. Pretty neat and it’s been very useful in saving me lots of time over many years.   The news for SQL Prompt 6 is that Red Gate have added a new Snippet Command of $PASTE$. Let’s alter our snippet to the following and try it out   Once again, we will type type “ifobj” in the SSMS Editor but first of all, highlight the name of the table #TestTable and copy it to your clipboard. Now type “ifobj” and press Tab… Wherever the string $PASTE$ is placed in the snippet, the contents of your clipboard are merged into the pasted TSQL. This means I don’t need to type the table name into the code snippet, it’s already there and I am seeing a fully functioning piece of TSQL ready to run. This means it is it even easier to write TSQL quickly and consistently. Attention to detail like this from Red Gate means that their developer tools stay on track to keep winning awards year after year and help take the hard work out of writing neat, accurate TSQL. If you want to try out SQL Prompt all the details are at http://www.red-gate.com/products/sql-development/sql-prompt/.

  Read the article

• Why Are We Here?

  - by Jonathan Mills

  Back in the early 2000s, Toyota had a vision of building the number one best selling minivan in North America. Their current minivan, the Sienna, was small, underpowered, and badly needed help.  Yuji Yokoya was given the job of re-engineering the Sienna. There was just one problem, Yuji, lived in Japan. He did not know the people or places that he would be engineering for. Believe it or not, Japan is nothing like North America. So, what does a chief engineer do in a situation like that? He packed up his team and flew halfway around the world. He made a commitment to drive through every state in the US, every province in Canada, and Mexico. He met the people and drove the roads that the Sienna would be driving. And guess what, what he learned on that trip revolutionized the Sienna. The innovations he made, sent the Sienna to number one. Why? Because he knew who he was building his product for. He knew, why he was there.Let me ask you this, do you know why you are building what you are building? As a member of a product team, can you tell me how your product will be used in the real world? As you are writing code, building test plans, writing stories, or any of the other project tasks, can you picture the face of a person who will be using what you are building? All to often, the answer to those questions is, no. Why is it important? Because, every day, project team members make assumptions. Over a given project, it is safe to say project team members will make thousands of assumptions about what they are doing. And all to often, those assumptions are not quite right. Its not that they are not good at their job, its just that they don’t really know why they are there.So, what to do? First and foremost, stop doing what you are doing. Yes, really. Schedule some time to go visit the people who will be using your product. Don’t invite them to you, go to them. Watch them work. Interact with them. Ask them questions. Maybe even try it out yourself. This serves two purposes. One, It shows them that you care about them. They will be far more engaged in your project if they feel like you care. And nothing says you care more that spending some time. Second, if gives you the proper frame of reference for you work. It gives you something tangible to go back to as you are building your product. As you make the thousands of assumptions that you will make over the life of your project, it gives you something to see in your mind that makes it real to you.Ultimately, setting a proper frame of reference is critical to the overall success of a project. The funny thing is, it really does not even take that long. In most cases, a 2-3 hour session will give you most of what you need to get the right insight. For the project, it will be the best 2 hours you could spend.

  Read the article

• What are they buying &ndash; work or value?

  - by Jamie Kurtz

  When was the last time you ordered a pizza like this: “I want the high school kid in the back to do the following… make a big circle with some dough, curl up the edges, then put some sauce on it using a small ladle, then I want him to take a handful of shredded cheese from the metal container and spread it over the circle and sauce, then finally I want the kid to place 36 pieces of pepperoni over the top of the cheese” ?? Probably never. My typical pizza order usually goes more like this: “I want a large pepperoni pizza”. In the world of software development, we try so hard to be all things agile. We: Write lots of unit tests We refactor our code, then refactor it some more We avoid writing lengthy requirements documents We try to keep processes to a minimum, and give developers freedom And we are proud of our constantly shifting focus (i.e. we’re “responding to change”) Yet, after all this, we fail to really lean and capitalize on one of agile’s main differentiators (from the twelve principles behind the Agile Manifesto): “Working software is the primary measure of progress.” That is, we foolishly commit to delivering tasks instead of features and bug fixes. Like my pizza example above, we fall into the trap of signing contracts that bind us to doing tasks – rather than delivering working software. And the biggest problem here… by far the most troubling outcome… is that we don’t let working software be a major force in all the work we do. When teams manage to ruthlessly focus on the end product, it puts them on the path of true agile. It doesn’t let them accidentally write too much documentation, or spend lots of time and money on processes and fancy tools. It forces early testing that reveals problems in the feature or bug fix. And it forces lots and lots of customer interaction.  Without that focus on the end product as your deliverable… by committing to a list of tasks instead of a list features and bug fixes… you are doomed to NOT be agile. You will end up just doing stuff, spending time on the keyboard, burning time on timesheets. Doing tasks doesn’t force you to minimize documentation. It makes it much harder to respond to change. And it will eventually force you and the client into contract haggling. Because the customer isn’t really paying you to do stuff. He’s ultimately paying for features and bug fixes. And when the customer doesn’t get what they want, responding with “well, look at the contract - we did all the tasks we committed to” doesn’t typically generate referrals or callbacks. In short, if you’re trying to deliver real value to the customer by going agile, you will most certainly fail if all you commit to is a list of things you’re going to do. Give agile what it needs by committing to features and bug fixes – not a list of ToDo items. So the next time you are writing up a contract, remember that the customer should be buying this: Not this:

  Read the article

• “Apparently, you signed a software services agreement without fully understanding it.”

  - by Dave Ballantyne

  I am not a lawyer. Let me say that again, I am not a lawyer. Todays Dilbert has prompted me to post about my recent experience with SqlServer licensing. I'm in the technical realm and rarely have much to do with purchasing and licensing.  I say “I need” , budget realities will state weather I actually get.  However, I do keep my ear to the ground and due to my community involvement, I know, or at least have an understanding of, some licensing restrictions. Due to a misunderstanding, Microsoft Licensing stated that we needed licenses for our standby servers.  I knew that that was not the case,  and a quick tweet confirmed this. So after composing an email stating exactly what the machines in question were used for ie Log shipped to and used in a disaster recover scenario only,  and posting several Technet articles to back this up, we saved 2 enterprise edition licences, a not inconsiderable cost. However during this discussion, I was made aware of another ‘legalese’ document that could completely override the referenced articles, and anything I knew, or thought i knew, about SqlServer licensing. Personally, I had no knowledge of this.  The “Purchase Use Rights” agreement would appear to be the volume licensing equivalent of the “End User License Agreement” , click throughs we all know and ignore.  Here is a direct quote from Microsoft licensing, when asked for clarification. “Thanks for your email. Just to give some background on the Product Use Rights (PUR), licenses acquired through volume licensing are bound by the most recent PUR at the time of license acquisition. The link for the current PUR and PUR archive is http://www.microsoft.com/licensing/about-licensing/product-licensing.aspx. Further to this, products acquired through boxed product or pre-installed on hardware (OEM) are bound by the End User License Agreement (EULA). The PUR will explain limitations, license requirements and rulings on areas like multiplexing, virtualization, processor licensing, etc. When an article will appear on a Microsoft site or blog describing the licensing of a product, it will be using the PUR as a base. Due to the writing style or language used by the person writing areas of the website or technical blogs, the PUR is what you should use as a rule and not any of the other media. The PUR is updated quarterly and will reference every product available at that time working on the latest version unless otherwise stated. The crux of this is that the PUR is written after extensive discussions between the different branches of Microsoft (legal, technical, etc) and the wording is then approved. This is not always the case for some pages explaining licensing as they are merely intended to advise and not subject to the intense scrutiny as the PUR.” So, exactly what does that mean ? My take :  This is a living document, “updated quarterly” , though presumably this could be done on a whim and a fancy.  It could state , you are only licensed if ,that during install you stand in a corner juggling and that photographic evidence is required. A plainly ridiculous demand but,  what else could it override or new requirements could it state that change your existing understanding of the product or your legal usage of it. As i say, im not a lawyer, but are you checking the PURA prior to purchase ?

  Read the article

• Welcome to BlogEngine.NET 2.9 using Microsoft SQL Server

  If you see this post it means that BlogEngine.NET 2.9 is running and the hard part of creating your own blog is done. There is only a few things left to do. Write Permissions To be able to log in to the blog and writing posts, you need to enable write permissions on the App_Data folder. If you’re blog is hosted at a hosting provider, you can either log into your account’s admin page or call the support. You need write permissions on the App_Data folder because all posts, comments, and blog attachments are saved as XML files and placed in the App_Data folder.  If you wish to use a database to to store your blog data, we still encourage you to enable this write access for an images you may wish to store for your blog posts.  If you are interested in using Microsoft SQL Server, MySQL, SQL CE, or other databases, please see the BlogEngine wiki to get started. Security When you've got write permissions to the App_Data folder, you need to change the username and password. Find the sign-in link located either at the bottom or top of the page depending on your current theme and click it. Now enter "admin" in both the username and password fields and click the button. You will now see an admin menu appear. It has a link to the "Users" admin page. From there you can change the username and password.  Passwords are hashed by default so if you lose your password, please see the BlogEngine wiki for information on recovery. Configuration and Profile Now that you have your blog secured, take a look through the settings and give your new blog a title.  BlogEngine.NET 2.9 is set up to take full advantage of of many semantic formats and technologies such as FOAF, SIOC and APML. It means that the content stored in your BlogEngine.NET installation will be fully portable and auto-discoverable.  Be sure to fill in your author profile to take better advantage of this. Themes, Widgets & Extensions One last thing to consider is customizing the look of your blog.  We have a few themes available right out of the box including two fully setup to use our new widget framework.  The widget framework allows drop and drag placement on your side bar as well as editing and configuration right in the widget while you are logged in.  Extensions allow you to extend and customize the behaivor of your blog.  Be sure to check the BlogEngine.NET Gallery at dnbegallery.org as the go-to location for downloading widgets, themes and extensions. On the web You can find BlogEngine.NET on the official website. Here you'll find tutorials, documentation, tips and tricks and much more. The ongoing development of BlogEngine.NET can be followed at CodePlex where the daily builds will be published for anyone to download.  Again, new themes, widgets and extensions can be downloaded at the BlogEngine.NET gallery. Good luck and happy writing. The BlogEngine.NET team

  Read the article

• Should I expose IObservable<T> on my interfaces?

  - by Alex

  My colleague and I have dispute. We are writing a .NET application that processes massive amounts of data. It receives data elements, groups subsets of them into blocks according to some criterion and processes those blocks. Let's say we have data items of type Foo arriving some source (from the network, for example) one by one. We wish to gather subsets of related objects of type Foo, construct an object of type Bar from each such subset and process objects of type Bar. One of us suggested the following design. Its main theme is exposing IObservable objects directly from the interfaces of our components. // ********* Interfaces ********** interface IFooSource { // this is the event-stream of objects of type Foo IObservable<Foo> FooArrivals { get; } } interface IBarSource { // this is the event-stream of objects of type Bar IObservable<Bar> BarArrivals { get; } } / ********* Implementations ********* class FooSource : IFooSource { // Here we put logic that receives Foo objects from the network and publishes them to the FooArrivals event stream. } class FooSubsetsToBarConverter : IBarSource { IFooSource fooSource; IObservable<Bar> BarArrivals { get { // Do some fancy Rx operators on fooSource.FooArrivals, like Buffer, Window, Join and others and return IObservable<Bar> } } } // this class will subscribe to the bar source and do processing class BarsProcessor { BarsProcessor(IBarSource barSource); void Subscribe(); } // ******************* Main ************************ class Program { public static void Main(string[] args) { var fooSource = FooSourceFactory.Create(); var barsProcessor = BarsProcessorFactory.Create(fooSource) // this will create FooSubsetToBarConverter and BarsProcessor barsProcessor.Subscribe(); fooSource.Run(); // this enters a loop of listening for Foo objects from the network and notifying about their arrival. } } The other suggested another design that its main theme is using our own publisher/subscriber interfaces and using Rx inside the implementations only when needed. //********** interfaces ********* interface IPublisher<T> { void Subscribe(ISubscriber<T> subscriber); } interface ISubscriber<T> { Action<T> Callback { get; } } //********** implementations ********* class FooSource : IPublisher<Foo> { public void Subscribe(ISubscriber<Foo> subscriber) { /* ... */ } // here we put logic that receives Foo objects from some source (the network?) publishes them to the registered subscribers } class FooSubsetsToBarConverter : ISubscriber<Foo>, IPublisher<Bar> { void Callback(Foo foo) { // here we put logic that aggregates Foo objects and publishes Bars when we have received a subset of Foos that match our criteria // maybe we use Rx here internally. } public void Subscribe(ISubscriber<Bar> subscriber) { /* ... */ } } class BarsProcessor : ISubscriber<Bar> { void Callback(Bar bar) { // here we put code that processes Bar objects } } //********** program ********* class Program { public static void Main(string[] args) { var fooSource = fooSourceFactory.Create(); var barsProcessor = barsProcessorFactory.Create(fooSource) // this will create BarsProcessor and perform all the necessary subscriptions fooSource.Run(); // this enters a loop of listening for Foo objects from the network and notifying about their arrival. } } Which one do you think is better? Exposing IObservable and making our components create new event streams from Rx operators, or defining our own publisher/subscriber interfaces and using Rx internally if needed? Here are some things to consider about the designs: In the first design the consumer of our interfaces has the whole power of Rx at his/her fingertips and can perform any Rx operators. One of us claims this is an advantage and the other claims that this is a drawback. The second design allows us to use any publisher/subscriber architecture under the hood. The first design ties us to Rx. If we wish to use the power of Rx, it requires more work in the second design because we need to translate the custom publisher/subscriber implementation to Rx and back. It requires writing glue code for every class that wishes to do some event processing.

  Read the article

• How do you go from a so so programmer to a great one? [closed]

  - by Cervo

  How do you go from being an okay programmer to being able to write maintainable clean code? For example David Hansson was writing Basecamp when in the process he created Rails as part of writing Basecamp in a clean/maintainable way. But how do you know when there is value in a side project like that? I have a bachelors in computer science, and I am about to get a masters and I will say that colleges teach you to write code to solve problems, not neatly or anything. Basically you think of a problem, come up with a solution, and write it down...not necessarily the most maintainable way in the world. Also my first job was in a startup, and now my third is in a small team in a large company where the attitude was/is get it done yesterday (also most of my jobs are mainly database development with SQL with a few ASP.NET web pages/.NET apps on the side). So of course cut/paste is more favored than making things more cleanly. And they would rather have something yesterday even if you have to rewrite it next month rather than to have something in a week that lasts for a year. Also spaghetti code turns up all over the place, and it takes very smart people to write/understand/maintain spaghetti code...However it would be better to do things so simple/clean that even a caveman/woman could do maintenance. Also I get very bored/unmotivated having to go modify the same things cut/pasted in a few locations. Is this the type of skill that you need to learn by working with a serious software organization that has an emphasis on maintenance and maybe even an architect who designs a system architecture and reviews code? Could you really learn it by volunteering on an open source project (it seems to me that a full time programmer job is way more practice than a few hours a week on an open source project)? Is there some course where you can learn this? I can attest that graduate school and undergraduate school do not really emphasize clean software at all. They just teach the structures/algorithms and then send you off into the world to solve problems. Overall I think the first thing is learning to write clean/maintainable code within the bounds of the project in order to become a good programmer. Then the next thing is learning when you need to do a side project (like a framework) to make things more maintainable/clean even while you still deliver things for the deadline in order to become a great programmer. For example, you are making an SQL report and someone gives you 100 calculations for individual columns. At what point does it make sense to construct a domain specific language to encode the rules in simply and then generate all the SQL as opposed to cut/pasting the query from the table a bunch of times and then adjusting each query to do the appropriate calculations. This is the type of thing I would say a great programmer would know. He/she would maybe even know ways to avoid the domain specific language and to still do all the calculations without creating an unmaintainable mess or a ton of repetitive code to cut/paste everywhere.

  Read the article

• Make a Perl-style regex interpreter behave like a basic or extended regex interpreter

  - by Barry Brown

  I am writing a tool to help students learn regular expressions. I will probably be writing it in Java. The idea is this: the student types in a regular expression and the tool shows which parts of a text will get matched by the regex. Simple enough. But I want to support several different regex "flavors" such as: Basic regular expressions (think: grep) Extended regular expressions (think: egrep) A subset of Perl regular expressions, including the character classes \w, \s, etc. Sed-style regular expressions Java has the java.util.Regex class, but it supports only Perl-style regular expressions, which is a superset of the basic and extended REs. What I think I need is a way to take any given regular expression and escape the meta-characters that aren't part of a given flavor. Then I could give it to the Regex object and it would behave as if it was written for the selected RE interpreter. For example, given the following regex: ^\w+[0-9]{5}-(\d{4})?$ As a basic regular expression, it would be interpreted as: ^\\w\+[0-9]\{5\}-\(\\d\{4\}\)\?$ As an extended regular expression, it would be: ^\\w+[0-9]{5}-(\\d{4})?$ And as a Perl-style regex, it would be the same as the original expression. Is there a "regular expression for regular expressions" than I could run through a regex search-and-replace to quote the non-meta characters? What else could I do? Are there alternative Java classes I could use?

  Read the article

• [ExtJs] Vs [Ext GWT] Vs [SmartGWT]

  - by shafi

  Hi, I am going to start a new application which mainly consist NavigationPane, Grid, Toolbar. Layout should look like this demo page http://www.gwt-ext.com/demo/ I am quite confused which one to use in terms of writing less code, more performant, etc.. Could someone tell the pros and cons of all these technologies. All the while I coded in javascript, so that way ExtJs seems to be the easy one for me to code. But I am curios to try GWT Ext, Is it true that it could do a lot just by writing few lines of java code. For eg: To achieve the layout ( given in above gwt ext demo url), which one should I opt ExtJs or GWT Ext. I read SmartGWT is relatively slower than GwtEXT. Does it have any advantage over GWT EXT. I am also looking for hibernate based data modules ( as my application is going to have many database calls). Anyone of SmartGWT or GWTExt has support for such modules. I came to know that smartgwt doesn't offer all of smartclient enterprise version functionalities, that we are allowed only a few of smartclient features. Will it be an issue? Your response is highly appreciated. Thanks & Regards `Shafi

  Read the article

• How To Create Your Own x86 Operating System for Modern PC Computers

  - by mudge

  I'd like to create a new operating system for x86 PC computers. I'd like it to be 64-bit but possibly run as 32-bit as well. I have these kinds of questions: What kinds of things do you start working on first? Knowing where to start in writing your own operating system seems to me to be a tricky subject, so I am interested in your input. Generally how to go about making your own 32-bit/64-bit operating system, or good resources that mention useful information about going about writing your own operating system for x86 computers. I don't care how old sources are as long as they are still relevant and useful to what I am doing. I know that I will want it to have kernel drivers that access peripheral hardware directly. Where should I look for advice and documentation for programming and understanding the interface to peripheral hardware the operating system will communicate with? I will need to understand how the operating system will receive input and interact with keyboards, mice, computer monitors, hard drives, USB, etc. etc. This is probably the area I know least about. I have the Intel instruction set manuals and have been getting more familiar with assembly programming, so the CPU side of things is what I know the most about. At this point I'm thinking that I'd like to implement the Linux system calls within my operating system so that programs that run on Linux can run on my operating system. I want my operating system to use the ELF binary format. I wonder what obstacles I have to overcome to achieve this Linux compatibility. Are the main things implementing the system calls that Linux provides, and using the ELF format? What else? I am also interested in people's thoughts about why it might not be a good idea to make your own operating system, and why it is a good idea to make your own operating system. Thank you for any input.

  Read the article

• Javascript/Greasemonkey: search for something then set result as a value

  - by thewinchester

  Ok, I'm a bit of a n00b when it comes to JS (I'm not the greatest programmer) so please be gentle - specially if my questions been asked already somewhere and I'm too stupid to find the right answer. Self deprecation out of the way, let's get to the question. Problem There is a site me and a large group of friends frequently use which doesn't display all the information we may like to know - in this case an airline bookings site and the class of travel. While the information is buried in the code of the page, it isn't displayed anywhere to the user. Using a Greasemonkey script, I'd like to liberate this piece of information and display it in a suitable format. Here's the psuedocode of what I'm looking to do. Search dom for specified element define variables Find a string of text If found Set result to a variable Write contents to page at a specific location (before a specified div) If not found Do nothing I think I've achieved most of it so far, except for the key bits of: Searching for the string: The page needs to search for the following piece of text in the page HEAD: mileageRequest += "&CLASSES=S,S-S,S-S"; The Content I need to extract and store is between the second equals (=) sign and the last comma ("). The contents of this area can be any letter between A-Z. I'm not fussed about splitting it up into an array so I could use the elements individually at this stage. Writing the result to a location: Taking that found piece of text and writing it to another location. Code so far This is what I've come up so far, with bits missing highlighted. buttons = document.getElementById('buttons'); ''Search goes here var flightClasses = document.createElement("div"); flightClasses.innerHTML = '<div id="flightClasses"> ' + '<h2>Travel classes</h2>' + 'For the above segments, your flight classes are as follows:' + 'write result here' + '</div>'; main.parentNode.insertBefore(flightClasses, buttons); If anyone could help me, or point me in the right direction to finish this off I'd appreciate it.

  Read the article

• How to use webbrowser control DocumentCompleted event in C# ?

  - by Margus

  Before starting writing this question, i was trying to solve following // 1. navigate to page // 2. wait until page is downloaded // 3. read and write some data from/to iframe // 4. submit (post) form The problem was, that if a iframe exists on a web page, DocumentCompleted event would get fired more then once (after each document has been completed). It was highly likely that program would have tried to read data from DOM that was not completed and naturally - fail. But suddenly while writing this question 'What if' monster inspired me, and i fix'ed the problem, that i was trying to solve. As i failed Google'ing this, i thought it would be nice to post it here. private int iframe_counter = 1; // needs to be 1, to pass DCF test public bool isLazyMan = default(bool); /// <summary> /// LOCK to stop inspecting DOM before DCF /// </summary> public void waitPolice() { while (isLazyMan) Application.DoEvents(); } private void webBrowser1_Navigating(object sender, WebBrowserNavigatingEventArgs e) { if(!e.TargetFrameName.Equals("")) iframe_counter --; isLazyMan = true; } private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) { if (!((WebBrowser)sender).Document.Url.Equals(e.Url)) iframe_counter++; if (((WebBrowser)sender).Document.Window.Frames.Count <= iframe_counter) {//DCF test DocumentCompletedFully((WebBrowser)sender,e); isLazyMan = false; } } private void DocumentCompletedFully(WebBrowser sender, WebBrowserDocumentCompletedEventArgs e){ //code here } For now at least, my 5m hack seems to be working fine. Maybe i am really failing at querying google or MSDN, but i can not find: "How to use webbrowser control DocumentCompleted event in C# ?"

  Read the article

• File Translator to Export Animated 3D Character from Autodesk Maya as Quake MD2

  - by Andy R

  I'm wondering if anyone knows of a way to export geometry/textures for a rigged, animated character as Quake MD2? I’m developing an app for mobile devices, and I’ve found that MD2 works great for lightweight OpenGL rendering. I have several animated characters, and I’d like to export them as MD2 from Maya. Here are some of the things I have tried: Exporting FBX to 3D Studio Max and using the QTip plugin -- this works, but only if I convert my animation to point cache (pc2) and bring that into Max. When I do that, QTip plugin doesn’t honor the point cache node, and all I get is the model, no animation Exporting OBJ Sequence to Blender, exporting MD2 from there -- I can’t seem to get blender to compile the imported obj sequence into a single animated object Exporting FBX to Milkshape -- the maya rig gets corrupted in the process Bake point cache for animation, export to FBX, import to Milkshape -- again, Milkshape doesn’t honor the geometry cache, so all that appears is a static character. I’m currently writing a plugin for Maya using the blender MD2 export script as reference (but re-writing using the C++ Maya API), but I’m just wondering if anyone has done this before or has any suggestions of how to do this. Also, if anyone has other suggestions for the best format to render a single animated character on an OpenGL ES (Android or iPhone) device, I would be very grateful! I’m open to trying anything to get these animations rendering on device Thanks!

  Read the article

• Fastest way to remove non-numeric characters from a VARCHAR in SQL Server

  - by Dan Herbert

  I'm writing an import utility that is using phone numbers as a unique key within the import. I need to check that the phone number does not already exist in my DB. The problem is that phone numbers in the DB could have things like dashes and parenthesis and possibly other things. I wrote a function to remove these things, the problem is that it is slow and with thousands of records in my DB and thousands of records to import at once, this process can be unacceptably slow. I've already made the phone number column an index. I tried using the script from this post: http://stackoverflow.com/questions/52315/t-sql-trim-nbsp-and-other-non-alphanumeric-characters But that didn't speed it up any. Is there a faster way to remove non-numeric characters? Something that can perform well when 10,000 to 100,000 records have to be compared. Whatever is done needs to perform fast. Update Given what people responded with, I think I'm going to have to clean the fields before I run the import utility. To answer the question of what I'm writing the import utility in, it is a C# app. I'm comparing BIGINT to BIGINT now, with no need to alter DB data and I'm still taking a performance hit with a very small set of data (about 2000 records). Could comparing BIGINT to BIGINT be slowing things down? I've optimized the code side of my app as much as I can (removed regexes, removed unneccessary DB calls). Although I can't isolate SQL as the source of the problem anymore, I still feel like it is.

  Read the article

• Creating a Custom Design-Time Environment

  - by Charlie

  Hello all, My question is related to the design-time support of WPF. From MSDN I read, The WPF Designer provides a framework and a public API which you can use to implement custom adorners, tools, property editors, and designers. But the vast majority of the examples I have found are trivial, and do not illustrate much concerning the creation of a customized designer in an existing WPF application. We have migrated our application from Windows Forms to WPF over the past year, and the next step will be to take an existing WinForms Panel designer, and rewrite it in WPF. Suffice it to say that this will be a huge project. But I don't even know where to begin. I am wondering if any of you have had similar experiences writing a customized designer for a WPF application, and what it was like. Even better, if you could compare and contrast the functionality between the WinForms designer and the WPF designer, or explain the transition from the former to the latter, that would be helpful. If you know of any simple examples that demonstrate a customized design environment (with custom controls, etc.) that would be extremely beneficial. All in all, I am just wondering if many people have undertaken this yet, and what their results have been. EDIT: To clarify, yes, I am talking about hosting a WPF designer. It appears that this may not even be possible, which is a huge setback. Here is a screenshot of our current WinForms designer. As you can see, it is used to create customized user interfaces. You can drag custom controls onto it and design them, then put the panel into a "run mode" in which all of the controls become functional. Short of spending months writing our designer, would this be possible in WPF? What about .NET 4.0 and VS2010? Will those add any designer functionality?

  Read the article

• Progress Bar design patterns?

  - by shoosh

  The application I'm writing performs a length algorithm which usually takes a few minutes to finish. During this time I'd like to show the user a progress bar which indicates how much of the algorithm is done as precisely as possible. The algorithm is divided into several steps, each with its own typical timing. For instance- initialization (500 milli-sec) reading inputs (5 sec) step 1 (30 sec) step 2 (3 minutes) writing outputs (7 sec) shutting down (10 milli-sec) Each step can report its progress quite easily by setting the range its working on, say [0 to 150] and then reporting the value it completed in its main loop. What I currently have set up is a scheme of nested progress monitors which form a sort of implicit tree of progress reporting. All progress monitors inherit from an interface IProgressMonitor: class IProgressMonitor { public: void setRange(int from, int to) = 0; void setValue(int v) = 0; }; The root of the tree is the ProgressMonitor which is connected to the actual GUI interface: class GUIBarProgressMonitor : public IProgressMonitor { GUIBarProgressMonitor(ProgressBarWidget *); }; Any other node in the tree are monitors which take control of a piece of the parent progress: class SubProgressMonitor : public IProgressMonitor { SubProgressMonitor(IProgressMonitor *parent, int parentFrom, int parentLength) ... }; A SubProgressMonitor takes control of the range [parentFrom, parentFrom+parentLength] of its parent. With this scheme I am able to statically divide the top level progress according to the expected relative portion of each step in the global timing. Each step can then be further subdivided into pieces etc' The main disadvantage of this is that the division is static and it gets painful to make changes according to variables which are discovered at run time. So the question: are there any known design patterns for progress monitoring which solve this issue?

  Read the article

• C# wrapper and Callbacks

  - by fergs

  I'm in the process of writing a C# wrapper for Dallmeier Common API light (Camera & Surviellance systems) and I've never written a wrapper before, but I have used the Canon EDSDK C# wrapper. So I'm using the Canon wrapper as a guide to writing the Dallmeier wrapper. I'm currently having issues with wrapping a callback. In the API manual it has the following: dlm_connect int(unsigned long uLWindowHandle, const char * strIP, const char* strUser1, const char* strPwd1, const char* strUser2, const char* strPwd2, void (*callback)(void *pParameters, void *pResult, void *pInput), void * pInput) Arguments - ulWindowhandle - handle of the window that is passed to the ViewerSDK to display video and messages there - strUser1/2 - names of the users to log in. If only single user login is used strUser2 is - NULL - strPwd1/2 - passwords of both users. If strUser2 is NULL strPwd2 is ignored. Return This function creates a SessionHandle that has to be passed Callback pParameters will be structured: - unsigned long ulFunctionID - unsigned long ulSocketHandle, //handle to socket of the established connection - unsigned long ulWindowHandle, - int SessionHandle, //session handle of the session created - const char * strIP, - const char* strUser1, - const char* strPwd1, - const char* strUser2, - const char * strPWD2 pResult is a pointer to an integer, representing the result of the operation. Zero on success. Negative values are error codes. So from what I've read on the Net and Stack Overflow - C# uses delegates for the purpose of callbacks. So I create a my Callback function : public delegate uint DallmeierCallback(DallPparameters pParameters, IntPtr pResult, IntPtr pInput); I create the connection function [DllImport("davidapidis.dll")] public extern static int dlm_connect(ulong ulWindowHandle, string strIP, string strUser1, string strPwd1, string strUser2, string strPwd2, DallmeierCallback inDallmeierFunc And (I think) the DallPParameters as a struct : [StructLayout(LayoutKind.Sequential)] public struct DallPParameters { public ulong ulfunctionID; public ulong ulsocketHandle; public ulong ulWindowHandle; ... } All of this is in my wrapper class. Am I heading in the right direction or is this completely wrong?

  Read the article

• Nonblocking Tcp server

  - by hoodoos

  It's not a question really, i'm just looking for some guidelines :) I'm currently writing some abstract tcp server which should use as low number of threads as it can. Currently it works this way. I have a thread doing listening and some worker threads. Listener thread is just sits and wait for clients to connect I expect to have a single listener thread per server instance. Worker threads are doing all read/write/processing job on clients socket. So my problem is in building efficient worker process. And I came to some problem I can't really solve yet. Worker code is something like that(code is really simple just to show a place where i have my problem): List<Socket> readSockets = new List<Socket>(); List<Socket> writeSockets = new List<Socket>(); List<Socket> errorSockets = new List<Socket>(); while( true ){ Socket.Select( readSockets, writeSockets, errorSockets, 10 ); foreach( readSocket in readSockets ){ // do reading here } foreach( writeSocket in writeSockets ){ // do writing here } // POINT2 and here's the problem i will describe below } it works all smothly accept for 100% CPU utilization because of while loop being cycling all over again, if I have my clients doing send-receive-disconnect routine it's not that painful, but if I try to keep alive doing send-receive-send-receive all over again it really eats up all CPU. So my first idea was to put a sleep there, I check if all sockets have their data send and then putting Thread.Sleep in POINT2 just for 10ms, but this 10ms later on produces a huge delay of that 10ms when I want to receive next command from client socket.. For example if I don't try to "keep alive" commands are being executed within 10-15ms and with keep alive it becomes worse by atleast 10ms :( Maybe it's just a poor architecture? What can be done so my processor won't get 100% utilization and my server to react on something appear in client socket as soon as possible? Maybe somebody can point a good example of nonblocking server and architecture it should maintain?

  Read the article

• Source of parsers for programming languages?

  - by Arkaaito

  I'm dusting off an old project of mine which calculates a number of simple metrics about large software projects. One of the metrics is the length of files/classes/methods. Currently my code "guesses" where class/method boundaries are based on a very crude algorithm (traverse the file, maintaining a "current depth" and adjusting it whenever you encounter unquoted brackets; when you return to the level a class or method began on, consider it exited). However, there are many problems with this procedure, and a "simple" way of detecting when your depth has changed is not always effective. To make this give accurate results, I need to use the canonical way (in each language) of detecting function definitions, class definitions and depth changes. This amounts to writing a simple parser to generate parse trees containing at least these elements for every language I want my project to be applicable to. Obviously parsers have been written for all these languages before, so it seems like I shouldn't have to duplicate that effort (even though writing parsers is fun). Is there some open-source project which collects ready-to-use parser libraries for a bunch of source languages? Or should I just be using ANTLR to make my own from scratch? (Note: I'd be delighted to port the project to another language to make use of a great existing resource, so if you know of one, it doesn't matter what language it's written in.)

  Read the article

• JSON: Jackson stream parser - is it really worth it?

  - by synic

  I'm making pretty heavy use of JSON parsing in an app I'm writing. Most of what I have done is already implemented using Android's built in JSONObject library (is it json-lib?). JSONObject appears to create instances of absolutely everything in the JSON string... even if I don't end up using all of them. My app currently runs pretty well, even on a G1. My question is this: are the speed and memory benefits from using a stream parser like Jackson worth all the trouble? By trouble, I mean this: As far as I can tell, there are three downsides to using Jackson instead of the built in library: Dependency on an external library. This makes your .apk bigger in the end. Not a huge deal. Your app is more fragile. Since the parsing is not done automatically, it is more vulnerable to changes in the JSON text that it's parsing. I'm extremely worried that malformed JSON will result in infinite loops (as pull parsing requires a lot of while loops). Writing code to parse JSON via a stream parser is ugly and tedious.

  Read the article

• UTF-8 BOM signature in PHP files

  - by skidding

  I was writing some commented PHP classes and I stumbled upon a problem. My name (for the @author tag) ends up with a ? (which is a UTF-8 character, ...and a strange name, I know). Even though I save the file as UTF-8, some friends reported that they see that character totally messed up (È™). This problem goes away by adding the BOM signature. But that thing troubles me a bit, since I don't know that much about it, except from what I saw on Wikipedia and on some other similar questions here on SO. I know that it adds some things at the beginning of the file, and from what I understood it's not that bad, but I'm concerned because the only problematic scenarios I read about involved PHP files. And since I'm writing PHP classes to share them, being 100% compatible is more important than having my name in the comments. But I'm trying to understand the implications, should I use it without worrying? or are there cases when it might cause damage? When? Thanks!

  Read the article

• AudioFileWriteBytes fails with error code -40

  - by alexbw

  I'm trying to write raw audio bytes to a file using AudioFileWriteBytes(). Here's what I'm doing: void writeSingleChannelRingBufferDataToFileAsSInt16(AudioFileID audioFileID, AudioConverterRef audioConverter, ringBuffer *rb, SInt16 *holdingBuffer) { // First, figure out which bits of audio we'll be // writing to file from the ring buffer UInt32 lastFreshSample = rb->lastWrittenIndex; OSStatus status; int numSamplesToWrite; UInt32 numBytesToWrite; if (lastFreshSample < rb->lastReadIndex) { numSamplesToWrite = kNumPointsInWave + lastFreshSample - rb->lastReadIndex - 1; } else { numSamplesToWrite = lastFreshSample - rb->lastReadIndex; } numBytesToWrite = numSamplesToWrite*sizeof(SInt16); Then we copy the audio data (stored as floats) to a holding buffer (SInt16) that will be written directly to the file. The copying looks funky because it's from a ring buffer. UInt32 buffLen = rb->sizeOfBuffer - 1; for (int i=0; i < numSamplesToWrite; ++i) { holdingBuffer[i] = rb->data[(i + rb->lastReadIndex) & buffLen]; } Okay, now we actually try to write the audio from the SInt16 buffer "holdingBuffer" to the audio file. The NSLog will spit out an error -40, but also claims that it's writing bytes. No data is written to file. status = AudioFileWriteBytes(audioFileID, NO, 0, &numBytesToWrite, &holdingBuffer); rb->lastReadIndex = lastFreshSample; NSLog(@"Error = %d, wrote %d bytes", status, numBytesToWrite); return;

  Read the article

• Unit testing JSON output module, best practices

  - by Banang

  I am currently working on a module that takes one of our business objects and returns a json representation of that object to the caller. Due to limitations in our environment I am unable to use any existing json writer, so I have written my own, which is then used by the business object writer to serialize my objects. The json writer is tested in a way similar to this @Test public void writeEmptyArrayTest() { String expected = "[ ]"; writer.array().endArray(); assertEquals(expected, writer.toString()); } which is only manageable because of the small output each instruction produces, even though I keep feeling there must be a better way. The problem I am now facing is writing tests for the object writer module, where the output is much larger and much less manageable. The risk of spelling mistakes in the expected strings mucking up my tests seem too great, and writing code in this fashion seems both silly and unmanageable in a long term perspective. I keep feeling like I want to write tests to ensure that my tests are behaving correctly, and this feeling worries me. Therefore, is there a better way of doing this? Surely there must be? Does anyone know of any good literature in regard to this specific case (doesn't have to be json, but you know what I mean)? Grateful for all help.

  Read the article

< Previous Page | 80 81 82 83 84 85 86 87 88 89 90 91  | Next Page >