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  • Divide a path into N sections using Java or PostgreSQL/PostGIS

    - by Guido
    Imagine a GPS tracking system that is following the position of several objects. The points are stored in a database (PostgreSQL + PostGIS). Each path is composed by a different number of points. That is the reason why, in order to compare a pair of paths, I need to divide every path in a set of 100 points. Do you know any PostGIS function that already implement this algorithm? I've not been able to find it. If not, I'd like to solve it using Java. In this case I'd like to know an efficient and easy to implement algorithm to divide a path into N points. The most simple example could be to divide this path into three points: position 1 : x=1, y=2 position 2 : x=1, y=3 And the result should be: position 1 : x=1, y=2 (starting point) position 2 : x=5, y=2.5 position 3 : x=9, y=3 (end point) Edit: By 'compare a pair of paths' I mean to calculate the distance between two paths. I plan to divide each path in 100 points, and sum the euclidean distance between each one of these points as the distance between the two paths.

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  • Passing youtube video id from video feed to flash

    - by Grant Anderson
    I'm working on a flash web application (Actionscript 2.0) for my honours project but am having trouble embedding youtube videos. Basically the user selects symbols which queries the youtube api with certain tags depending on the symbols chosenand a random video is then picked from the first 30 videos. I have this working using the following code: on (release) { url="http://gdata.youtube.com/feeds/api/videos?q=danger+passion&orderby=published&start-index="+random(30)+"&max-results=1&v=2" getURL(url); } but this just displays a webpage with a link to the youtube video. This is the code I'll be using as the foundations for the player: // create a MovieClip to load the player into var ytplayer:MovieClip = _root.createEmptyMovieClip("ytplayer", 1); // create a listener object for the MovieClipLoader to use var ytPlayerLoaderListener:Object = { onLoadInit: function() { // When the player clip first loads, we start an interval to // check for when the player is ready loadInterval = setInterval(checkPlayerLoaded, 250); } }; var loadInterval:Number; function checkPlayerLoaded():Void { // once the player is ready, we can subscribe to events, or in the case of // the chromeless player, we could load videos if (ytplayer.isPlayerLoaded()) { ytplayer.addEventListener("onStateChange", onPlayerStateChange); ytplayer.addEventListener("onError", onPlayerError); clearInterval(loadInterval); } } function onPlayerStateChange(newState:Number) { trace("New player state: "+ newState); } function onPlayerError(errorCode:Number) { trace("An error occurred: "+ errorCode); } // create a MovieClipLoader to handle the loading of the player var ytPlayerLoader:MovieClipLoader = new MovieClipLoader(); ytPlayerLoader.addListener(ytPlayerLoaderListener); // load the player ytPlayerLoader.loadClip("http://www.youtube.com/v/pv5zWaTEVkI", ytplayer); can anyone help me on how to get the id of the video (for example: pv5zWaTEVkI) from the feed? Or how to send a query from flash which will return the video url/id as opposed to the url of a feed. Any help would be much appreciated as my hand in rather soon. Thanks

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  • What is the general feeling about reflection extensions in std::type_info?

    - by Evan Teran
    I've noticed that reflection is one feature that developers from other languages find very lacking in c++. For certain applications I can really see why! It is so much easier to write things like an IDE's auto-complete if you had reflection. And certainly serialization APIs would be a world easier if we had it. On the other side, one of the main tenets of c++ is don't pay for what you don't use. Which makes complete sense. That's something I love about c++. But it occurred to me there could be a compromise. Why don't compilers add extensions to the std::type_info structure? There would be no runtime overhead. The binary could end up being larger, but this could be a simple compiler switch to enable/disable and to be honest, if you are really concerned about the space savings, you'll likely disable exceptions and RTTI anyway. Some people cite issues with templates, but the compiler happily generates std::type_info structures for template types already. I can imagine a g++ switch like -fenable-typeinfo-reflection which could become very popular (and mainstream libs like boost/Qt/etc could easily have a check to generate code which uses it if there, in which case the end user would benefit with no more cost than flipping a switch). I don't find this unreasonable since large portable libraries like this already depend on compiler extensions. So why isn't this more common? I imagine that I'm missing something, what are the technical issues with this?

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  • Query on object id in VQL

    - by Banang
    I'm currently working with the versant object database (using jvi), and have a case where I need to query the database based on an object id. What I'm trying to achieve is something along the lines of Employee employee = new Employee("Mr. Pickles"); session.commit(); FundVQLQuery q = new FundVQLQuery(session, "select * from Employee employee where employee = $1"); q.bind(employee); q.execute(); However, I'm finding out the hard way (I get an EVJ_NOT_A_VALID_KEY_TYPE error thrown at me) that this is infact not the way to do it. Anyone got any experience in working with VQL? Your help is much apreciated! A small clarification: The problem is I'm running some performance tests on the database using the pole position framework, and one of the tests in that framework requires me to fetch an object from the database using either an object reference or a low level object id. Thus, I'm not allowed to reference specific fields in the employee object, but must perform the query on the object in its entirety. So, it's not allowed for me to go "select * from Employee e where e.id = 4", I need it to use the entire object. Accepted answer: Since there is some sort of lunacy magic built into SO that prevents me to mark an accepted answer after a bounty has run out, readers should know that the answer posted by Chris Holmes solves this issue. Readers are encouraged to up-vote his post to further signalize the correctness of his answer to any future readers of this thread.

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  • How to send a JSONObject to a REST service?

    - by Sebi
    Retrieving data from the REST Server works well, but if I want to post an object it doesn't work: public static void postJSONObject(int store_type, FavoriteItem favorite, String token, String objectName) { String url = ""; switch(store_type) { case STORE_PROJECT: url = URL_STORE_PROJECT_PART1 + token + URL_STORE_PROJECT_PART2; //data = favorite.getAsJSONObject(); break; } HttpClient httpClient = new DefaultHttpClient(); HttpPost postMethod = new HttpPost(url); try { HttpEntity entity = new StringEntity("{\"ID\":0,\"Name\":\"Mein Projekt10\"}"); postMethod.setEntity(entity); HttpResponse response = httpClient.execute(postMethod); Log.i("JSONStore", "Post request, to URL: " + url); System.out.println("Status code: " + response.getStatusLine().getStatusCode()); } catch (ClientProtocolException e) { I always get a 400 Error Code. Does anybody know whats wrong? I have working C# code, but I can't convert: System.Net.WebRequest wr = System.Net.HttpWebRequest.Create("http://localhost:51273/WSUser.svc/pak3omxtEuLrzHSUSbQP/project"); wr.Method = "POST"; string data = "{\"ID\":1,\"Name\":\"Mein Projekt\"}"; byte [] d = UTF8Encoding.UTF8.GetBytes(data); wr.ContentLength = d.Length; wr.ContentType = "application/json"; wr.GetRequestStream().Write(d, 0, d.Length); System.Net.WebResponse wresp = wr.GetResponse(); System.IO.StreamReader sr = new System.IO.StreamReader(wresp.GetResponseStream()); string line = sr.ReadToEnd();

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  • How can I work around SQL Server - Inline Table Value Function execution plan variation based on par

    - by Ovidiu Pacurar
    Here is the situation: I have a table value function with a datetime parameter ,lest's say tdf(p_date) , that filters about two million rows selecting those with column date smaller than p_date and computes some aggregate values on other columns. It works great but if p_date is a custom scalar value function (returning the end of day in my case) the execution plan is altered an the query goes from 1 sec to 1 minute execution time. A proof of concept table - 1K products, 2M rows: CREATE TABLE [dbo].[POC]( [Date] [datetime] NOT NULL, [idProduct] [int] NOT NULL, [Quantity] [int] NOT NULL ) ON [PRIMARY] The inline table value function: CREATE FUNCTION tdf (@p_date datetime) RETURNS TABLE AS RETURN ( SELECT idProduct, SUM(Quantity) AS TotalQuantity, max(Date) as LastDate FROM POC WHERE (Date < @p_date) GROUP BY idProduct ) The scalar value function: CREATE FUNCTION [dbo].[EndOfDay] (@date datetime) RETURNS datetime AS BEGIN DECLARE @res datetime SET @res=dateadd(second, -1, dateadd(day, 1, dateadd(ms, -datepart(ms, @date), dateadd(ss, -datepart(ss, @date), dateadd(mi,- datepart(mi,@date), dateadd(hh, -datepart(hh, @date), @date)))))) RETURN @res END Query 1 - Working great SELECT * FROM [dbo].[tdf] (getdate()) The end of execution plan: Stream Aggregate Cost 13% <--- Clustered Index Scan Cost 86% Query 2 - Not so great SELECT * FROM [dbo].[tdf] (dbo.EndOfDay(getdate())) The end of execution plan: Stream Aggregate Cost 4% <--- Filter Cost 12% <--- Clustered Index Scan Cost 86%

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  • How to make a mapped field inherited from a superclass transient in JPA?

    - by Russ Hayward
    I have a legacy schema that cannot be changed. I am using a base class for the common features and it contains an embedded object. There is a field that is normally mapped in the embedded object that needs to be in the persistence id for only one (of many) subclasses. I have made a new id class that includes it but then I get the error that the field is mapped twice. Here is some example code that is much simplified to maintain the sanity of the reader: @MappedSuperclass class BaseClass { @Embedded private Data data; } @Entity class SubClass extends BaseClass { @EmbeddedId private SubClassId id; } @Embeddable class Data { private int location; private String name; } @Embeddable class SubClassId { private int thingy; private int location; } I have tried @AttributeOverride but I can only get it to rename the field. I have tried to set it to updatable = false, insertable = false but this did not seem to work when used in the @AttributeOverride annotation. See answer below for the solution to this issue. I realise I could change the base class but I really do not want to split up the embedded object to separate the shared field as it would make the surrounding code more complex and require some ugly wrapping code. I could also redesign the whole system for this corner case but I would really rather not. I am using Hibernate as my JPA provider.

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  • database schema eligible for delta synchronization

    - by WilliamLou
    it's a question for discussion only. Right now, I need to re-design a mysql database table. Basically, this table contains all the contract records I synchronized from another database. The contract record can be modified, deleted or users can add new contract records via GUI interface. At this stage, the table structure is exactly the same as the Contract info (column: serial number, expiry date etc.). In that case, I can only synchronize the whole table (delete all old records, replace with new ones). If I want to delta(only synchronize with modified, new, deleted records) synchronize the table, how should I change the database schema? here is the method I come up with, but I need your suggestions because I think it's a common scenario in database applications. 1)introduce a sequence number concept/column: for each sequence, mark the new added records, modified records, deleted records with this sequence number. By recording the last synchronized sequence number, only pass those records with higher sequence number; 2) because deleted contracts can be added back, and the original table has primary key constraints, should I create another table for those deleted records? or add a flag column to indicate if this contract has been deleted? I hope I explain my question clearly. Anyway, if you know any articles or your own suggestions about this, please let me know. Thanks!

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  • EAGLContext, EAGLSharegroups, RenderBuffers, FrameBuffers, oh my!

    - by quixoto
    Hi all, I'm trying to wrap my head around the OpenGL object model on iPhone OS. I'm currently rendering into a few different UIViews (build on CAEAGLayers) on the screen. I currently have each of these as using separate EAGLContext, each of which has a color renderbuffer and a framebuffer. I'm rendering similar things in them, and I'd like to share textures between these instances to save memory overhead. My current understanding is that I could use the same setup (some number of contexts, each with a FBO/RBO) but if I spawn the later ones using the EAGLShareGroup of the first one, then I can simply use the texture names (GLuints) from the first one in the later ones. Is this accurate? If this is the case, I guess the followup question is: what's the benefit to having it be a "sharegroup"? Could I just reuse the same context, and attach multiple FBOs/RBOs to that context? I think I'm struggling with the abstraction layer of a sharegroup, which seems to share "objects" (textures and other named things) but not "state" (matrices, enabled/disabled states) which are owned by the context. What's the best way to think of this? Thanks for any enlightenment!

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  • Microsoft Solver Foundation constraint

    - by emaster70
    Hello, I'm trying to use Microsoft Solver Foundation 2 to solve a fairly complicated situation, however I'm stuck with an UnsupportedModelException even when I dumb down the model as much as possible. Does anyone have an idea of what I'm doing wrong? Following is the least example required to reproduce the problematic behavior. var ctx = SolverContext.GetContext(); var model = ctx.CreateModel(); var someConstant = 1337.0; var decisionA = new Decision(Domain.Real, "decisionA"); var decisionB = new Decision(Domain.Real, "decisionB"); var decisionC = new Decision(Domain.Real, "decisionC"); model.AddConstraint("ca", decisionA <= someConstant); model.AddConstraint("cb", decisionB <= someConstant); model.AddConstraint("cc", decisionC <= someConstant); model.AddConstraint("mainConstraint", Model.Equal(Model.Sum(decisionA, decisionB, decisionC), someConstant)) model.AddGoal("myComplicatedGoal", GoalKind.Minimize, decisionC); var solution = ctx.Solve(); solution.GetReport().WriteTo(Console.Out); Console.ReadKey(); Please consider that my actual model should include, once complete, a few constraints in the form of a*a+b*a <= someValue, so if what I'm willing to do ultimately isn't supported, please let me know in advance. If that's the case I'd also appreciate a suggestion of some other solver with a .NET friendly interface that I could use (only well-known commercial packages, please). Thanks in advance

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  • PHP Switch and Login

    - by Steve Rivera
    I'm fairly new with PHP and I am messing around with a login/registration system. I setup my sample website using a PHP-SWITCH script I found a while back: <?php switch($_GET['id']) { default: include('home.php'); /* LOGIN PAGES */ break; case "register_form": include ('includes/user_system/register_form.php'); } ? On the registration page the form links to my "register.php" which checks the validity of the form and to check for any blank fields and so on. "register.php" is supposed to refresh the page and add a reason to what the user did wrong when submitting the form. On my "register_form.php" page, which holds the actual form. This field is hidden until the user makes a mistake. <?php if (isset($reg_error)) { ?> , please try again. My "register.php" checks the form for all the errors. Here's the bit of code that will refresh the page with the reason for the error: // Check if any of the fields are missing if (empty($_POST['username']) || empty($_POST['password']) || empty($_POST['confirmpass'])) { // Reshow the form with an error $reg_error = 'One or more fields missing'; include 'register_form.php'; Now after I submit the form without any fields filled out I get the error code, but it refreshes to the actual "register_form.php". The problem with this is that because of my PHP-SWITCH script (helps me manage the site a lot easier) I don't have any formatting on that page. The actual URL to my "register_form.php" would be: "index.php?id=register_form.php". Now I have tried several different things such as changing it to: include 'index.php?id=register_form.php' And also changing it to: header(location:index.php?id=register_form.php') Unfortunately all this does is refresh the page without the reason for the error. I know this can be easily solved by just adding a Javascript Validator but I'd like to know if it is possible to refresh the page with the error using either "include" or "header()" while having a PHP-SWITCH script on the website.

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  • Just messed up a server misusing chown, how to execute it correctly?

    - by Jack Webb-Heller
    Hi! I'm moving from an old shared host to a dedicated server at MediaTemple. The server is running Plesk CP, but, as far as I can tell, there's no way via the Interface to do what I want to do. On the old shared host, running cPanel, I creative a .zip archive of all the website's files. I downloaded this to my computer, then uploaded it with FTP to the new host account I'd set up. Finally, I logged in via SSH, navigated to the directory the zip was stored in (something like var/www/vhosts/mysite.com/httpdocs/ and ran the unzip command on the file sitearchive.zip. This extracted everything just the fine. The site appeared to work just fine. The problem: When I tried to edit a file through FTP, I got Error - 160: Permission Denied. When I Get Info for the file I'm trying to edit, it says the owner and group is swimwir1. I attemped to use chown at this point to change owner - and yes, as you may be able to tell, I'm a little inexperienced in SSH ;) luckily the server was new, since the command I ran - chown -R newuser / appeared to mess a load of stuff up. The reason I used / on the end rather than /var/www/vhosts/mysite.com/httpdocs/ was because I'd already cded into their, so I presumed the / was relative to where I was working. This may be the case, I have no idea, either way - Plesk was no longer accessible, although Apache and things continued to work. I realised my mistake, and deciding it wasn't worth the hassle of 1) being an amateur and 2) trying to fix it, I just reprovisioned the server to start afresh. So - what do I do to change the owner of these files correctly? Thanks for helping out a confused beginner! Jack

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  • Convert UCS-2 characters to UTF-8 Using C#

    - by quanticle
    I'm pulling some internationalized text from a MS SQL Server 2005 database. As per the defaults for that DB, the characters are stored as UCS-2. However, I need to output the data in UTF-8 format, as I'm sending it out over the web. Currently, I have the following code to convert: SqlString dbString = resultReader.GetSqlString(0); byte[] dbBytes = dbString.GetUnicodeBytes(); byte[] utf8Bytes = System.Text.Encoding.Convert(System.Text.Encoding.Unicode, System.Text.Encoding.UTF8, dbBytes); System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding(); string outputString = encoder.GetString(utf8Bytes); However, when I examine the output in the browser, it appears to be garbage, no matter what I set the encoding to. What am I missing? EDIT: In response to the answers below, the reason I thought I had to perform a conversion is because I can output literal multibyte strings just fine. For example: OutputControl.Text = "????????????????????????????????????????????????????????????????"; works. Here, OutputControl is an ASP.Net Literal. However, OutputControl.Text = outputString; //Output from above snippet results in mangled output as described above. My hypothesis was that the database's output was somehow getting mangled by ASP.Net. If that's not the case, then what are some other possibilities?

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  • Why is curl in Ruby slower than command-line curl?

    - by Stiivi
    I am trying to download more than 1m pages (URLs ending by a sequence ID). I have implemented kind of multi-purpose download manager with configurable number of download threads and one processing thread. The downloader downloads files in batches: curl = Curl::Easy.new batch_urls.each { |url_info| curl.url = url_info[:url] curl.perform file = File.new(url_info[:file], "wb") file << curl.body_str file.close # ... some other stuff } I have tried to download 8000 pages sample. When using the code above, I get 1000 in 2 minutes. When I write all URLs into a file and do in shell: cat list | xargs curl I gen all 8000 pages in two minutes. Thing is, I need it to have it in ruby code, because there is other monitoring and processing code. I have tried: Curl::Multi - it is somehow faster, but misses 50-90% of files (does not download them and gives no reason/code) multiple threads with Curl::Easy - around the same speed as single threaded Why is reused Curl::Easy slower than subsequent command line curl calls and how can I make it faster? Or what I am doing wrong? I would prefer to fix my download manager code than to make downloading for this case in a different way. Before this, I was calling command-line wget which I provided with a file with list of URLs. Howerver, not all errors were handled, also it was not possible to specify output file for each URL separately when using URL list. Now it seems to me that the best way would be to use multiple threads with system call to 'curl' command. But why when I can use directly Curl in Ruby? Code for the download manager is here, if it might help: Download Manager (I have played with timeouts, from not-setting it to various values, it did not seem help) Any hints appreciated.

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  • PHP $_SERVER['HTTP_HOST'] vs. $_SERVER['SERVER_NAME'], am I understanding the man pages correctly?

    - by Jeff
    I did a lot of searching and also read the PHP $_SERVER man page. Do I have this right regarding which to use for my PHP scripts for simple link definitions used throughout my site? $_SERVER['SERVER_NAME'] is based on your web servers' config file (Apache2 in my case), and varies depending on a few directives: (1) VirtualHost, (2) ServerName, (3) UseCanonicalName, etc. $_SERVER['HTTP_HOST'] is based on the request from the client. Therefore, it would seem to me that the proper one to use in order to make my scripts as compatible as possible would be $_SERVER['HTTP_HOST']. Is this assumption correct? Followup comments: I guess I got a little paranoid after reading this article and noting that someone said "they wouldn't trust any of the $_SERVER vars": http://markjaquith.wordpress.com/2009/09/21/php-server-vars-not-safe-in-forms-or-links/ and also: http://www.php.net/manual/en/reserved.variables.server.php (comment: Vladimir Kornea 14-Mar-2009 01:06) Apparently the discussion is mainly about $_SERVER['PHP_SELF'] and why you shouldn't use it in the form action attribute without proper escaping to prevent XSS attacks. My conclusion about my original question above is that it is "safe" to use $_SERVER['HTTP_HOST'] for all links on a site without having to worry about XSS attacks, even when used in forms. Please correct me if I'm wrong.

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  • Why should the "prime-based" hashcode implmentation be used instead of the "naive" one?

    - by Wilhelm
    I have seen that a prime number implmentation of the GetHashCode function is being recommend, for example here. However using the following code (in VB, sorry), it seems as if that implementation gives the same hash density as a "naive" xor implementation. If the density is the same, I would suppose there is the same probability of cllision in both implementations. Am I missing anything on why is the prime approach preferred? I am supossing that if the hash code is a byte I do not lose generality for the integer case. Sub Main() Dim XorHashes(255) As Integer Dim PrimeHashes(255) As Integer For i = 0 To 255 For j = 0 To 255 For k = 0 To 255 XorHashes(GetXorHash(i, j, k)) += 1 PrimeHashes(GetPrimeHash(i, j, k)) += 1 Next Next Next For i = 0 To 255 Console.WriteLine("{0}: {1}, {2}", i, XorHashes(i), PrimeHashes(i)) Next Console.ReadKey() End Sub Public Function GetXorHash(ByVal valueOne As Integer, ByVal valueTwo As Integer, ByVal valueThree As Integer) As Byte Return CByte((valueOne Xor valueTwo Xor valueThree) Mod 256) End Function Public Function GetPrimeHash(ByVal valueOne As Integer, ByVal valueTwo As Integer, ByVal valueThree As Integer) As Byte Dim TempHash = 17 TempHash = 31 * TempHash + valueOne TempHash = 31 * TempHash + valueTwo TempHash = 31 * TempHash + valueThree Return CByte(TempHash Mod 256) End Function

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  • How does the last integer promotion rule ever get applied in C?

    - by SiegeX
    6.3.1.8p1: Otherwise, the integer promotions are performed on both operands. Then the following rules are applied to the promoted operands: If both operands have the same type, then no further conversion is needed. Otherwise, if both operands have signed integer types or both have unsigned integer types, the operand with the type of lesser integer conversion rank is converted to the type of the operand with greater rank. Otherwise, if the operand that has unsigned integer type has rank greater or equal to the rank of the type of the other operand, then the operand with signed integer type is converted to the type of the operand with unsigned integer type. Otherwise, if the type of the operand with signed integer type can represent all of the values of the type of the operand with unsigned integer type, then the operand with unsigned integer type is converted to the type of the operand with signed integer type. Otherwise, both operands are converted to the unsigned integer type corresponding to the type of the operand with signed integer type. For the bolded rule to be applied it would seem to imply you need to have have an unsigned interger type who's rank is less than the signed integer type and the signed integer type cannot hold all the values of the unsigned integer type. Is there a real world example of such a case or is this statement serving as a catch-all to cover all possible permutations?

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  • Calling QAxWidget method outside of the GUI thread

    - by user304361
    I'm beginning to wonder if this is impossible, but I thought I'd ask in case there's a clever way to get around the problems I'm having. I have a Qt application that uses an ActiveX control. The control is held by a QAxWidget, and the QAxWidget itself is contained within another QWidget (I needed to add additional signals/slots to the widget, and I couldn't just subclass QAxWidget because the class doesn't permit that). When I need to interact with the ActiveX control, I call a method of the QWidget, which in turn calls the dynamicCall method of the QAxWidget in order to invoke the appropriate method of the ActiveX control. All of that is working fine. However, one method of the ActiveX control takes several seconds to return. When I call this method, my entire GUI locks up for a few seconds until the method returns. This is undesirable. I'd like the ActiveX control to go off and do its processing by itself and come back to me when it's done without locking up the Qt GUI. I've tried a few things without success: Creating a new QThread and calling QAxWidget::dynamicCall from the new thread Connecting a signal to the appropriate slot method of the QAxWidget and calling the method using signals/slots instead of using dynamicCall Calling QAxWidget::dynamicCall using QtConcurrent::run Nothing seems to affect the behavior. No matter how or where I use dynamicCall (or trigger the appropriate slot of the QAxWidget), the GUI locks until the ActiveX control completes its operation. Is there any way to detach this ActiveX processing from the Qt GUI thread so that the GUI doesn't lock up while the ActiveX control is running a method? Is there something clever I can do with QAxBase or QAxObject to get my desired results?

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  • twisted deferred/callbacks and asynchronous execution

    - by NetSkay
    hey guys, quick question about twisted and python... im trying to figure out how can i make my code more asynchronous using twisted and ive come to sort of a dead end, if a function of mine returns a deferred object, then i add a list of callbacks, the first callback will be called after the deferred function provides some result through deferred_obj.callback, then, in the chain of callbacks, the first callback will do something with the data and call the second callback and etc. however chained callbacks will not be considered asynchronous because they're chained and the event loop will keep firing each one of them concurrently until there is no more, right? however, if i have a deferred object, and i attach as its callback the deferred_obj.callback as in d.addCallback(deferred_obj.callback) then this will be considered asynchronous, because the deferred_obj is waiting for the data, and then the method that will pass the data is waiting on data as well, however once i d.callback 'd' object processes the data then it call deferred_obj.callback however since this object is deferred, unlike the case of chained callbacks, it will execute asynchronously... correct? meaning chained callbacks are NOT asynchronous while chained deferreds are, correct? thank you PS: assuming all of my code is non-blocking

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  • Replacement for deprecated SQL Server User Defined Type with a bound Rule and Default

    - by Adam Jones
    We have a User Defined Data Type of YesNo which has an which is an alias for char(1). The type has a bound Rule (must be Y or N) and a Default (N). The aim of this is that when any of the development team create a new field of type YesNo the rule and default are automatically bound to the new column. Rules and Defaults have been deprecated and won't be available in the next a future version of SQL Server, is there another way to achieve the same functionality? I should add that I'm aware that I could use CHECK and DEFAULT constraints to replicate the functionality of the bound Rule and Defalut objects, however these would have to be applied at each usage of the type, rather than getting the functionality 'for free' by using a UDT which has a bound Rule and Default. The post relates to a database that backs an existing application, rather than a new development, so I'm aware that our use of UDT's is less than optimal. I suspect the answer to the question is 'No', however normally when features are deprecated there's usually an alternative syntax that can be used as a drop in replacement so I wanted to pose the question in-case someone knew of an alternative.

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  • How is conversion of float/double to int handled in printf?

    - by Sandip
    Consider this program int main() { float f = 11.22; double d = 44.55; int i,j; i = f; //cast float to int j = d; //cast double to int printf("i = %d, j = %d, f = %d, d = %d", i,j,f,d); //This prints the following: // i = 11, j = 44, f = -536870912, d = 1076261027 return 0; } Can someone explain why the casting from double/float to int works correctly in the first case, and does not work when done in printf? This program was compiled on gcc-4.1.2 on 32-bit linux machine. EDIT: Zach's answer seems logical, i.e. use of format specifiers to figure out what to pop off the stack. However then consider this follow up question: int main() { char c = 'd'; // sizeof c is 1, however sizeof character literal // 'd' is equal to sizeof(int) in ANSI C printf("lit = %c, lit = %d , c = %c, c = %d", 'd', 'd', c, c); //this prints: lit = d, lit = 100 , c = d, c = 100 //how does printf here pop off the right number of bytes even when //the size represented by format specifiers doesn't actually match //the size of the passed arguments(char(1 byte) & char_literal(4 bytes)) return 0; } How does this work?

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  • How can I programmatically add more than just one view object to my view controller?

    - by BeachRunnerJoe
    I'm diving into iPhone OS development and I'm trying to understand how I can add multiple view objects to the "Left/Root" view of my SplitView iPad app. I've figured out how to programmatically add a TableView to that view based on the example code I found in Apple's online documentation... RootViewController.h @interface RootViewController : UITableViewController <NSFetchedResultsControllerDelegate, UITableViewDelegate, UITableViewDataSource> { DetailViewController *detailViewController; UITableView *tableView; NSFetchedResultsController *fetchedResultsController; NSManagedObjectContext *managedObjectContext; } RootViewController.m - (void)loadView { UITableView *newTableView = [[UITableView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame] style:UITableViewStylePlain]; newTableView.autoresizingMask = UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth; newTableView.delegate = self; newTableView.dataSource = self; [newTableView reloadData]; self.view = newTableView; [newTableView release]; } but there are a few things I don't understand about it and I was hoping you veterans could help clear up some confusion. In the statement self.view = newTableView, I assume I'm setting the entire view to a single UITableView. If that's the case, then how can I add additional view objects to that view alongside the table view? For example, if I wanted to have a DatePicker view object and the TableView object instead of just the TableView object, then how would I programmatically add that? Referencing the code above, how can I resize the table view to make room for the DatePicker view object that I'd like to add? Thanks so much in advance for your help! I'm going to continue researching these questions right now.

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  • Algorithm to detect how many words typed, also multi sentence support (Java)

    - by Alex Cheng
    Hello all. Problem: I have to design an algorithm, which does the following for me: Say that I have a line (e.g.) alert tcp 192.168.1.1 (caret is currently here) The algorithm should process this line, and return a value of 4. I coded something for it, I know it's sloppy, but it works, partly. private int counter = 0; public void determineRuleActionRegion(String str, int index) { if (str.length() == 0 || str.indexOf(" ") == -1) { triggerSuggestionList(1); return; } //remove duplicate space, spaces in front and back before searching int num = str.trim().replaceAll(" +", " ").indexOf(" ", index); //Check for occurances of spaces, recursively if (num == -1) { //if there is no space //no need to check if it's 0 times it will assign to 1 triggerSuggestionList(counter + 1); counter = 0; return; //set to rule action } else { //there is a space counter++; determineRuleActionRegion(str, num + 1); } } //end of determineactionRegion() So basically I find for the space and determine the region (number of words typed). However, I want it to change upon the user pressing space bar <space character>. How may I go around with the current code? Or better yet, how would one suggest me to do it the correct way? I'm figuring out on BreakIterator for this case... To add to that, I believe my algorithm won't work for multi sentences. How should I address this problem as well. -- The source of String str is acquired from textPane.getText(0, pos + 1);, the JTextPane. Thanks in advance. Do let me know if my question is still not specific enough.

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  • Cursor image to the center on mouseout

    - by Milla
    Hi all! I'm a real noobie with flash and I was wondering if somebody could help me with this one. I have this actionsript 3 code, where the cursor image "ball_mc" follows the mouse's position with a slight delay: stage.addEventListener(Event.ENTER_FRAME,followBall); function followBall(event:Event):void { var dx:int = ball_mc.x - mouseX; var dy:int = ball_mc.y - mouseY; ball_mc.x -= dx / 5; ball_mc.y -= dy /5; } 1) How can I get the cursor image automatically return to the center of the stage on mouseout? As of now, it stays at the position where the mouse leaves the stage. 2) How can I reverse the movement of the mouse? So that when I, for example, move mouse to the right, the cursor image would move to the left? And when moving the mouse up, the image would go down. The stage is 800 x 250 pixels, in case that makes any difference.

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  • verilog / systemverilog -- What is the behavior of blocking statements across two always blocks?

    - by miles.sherman
    I am wondering about the behavior of the below code. There are two always blocks, one is combinational to calculate the next_state signal, the other is sequential which will perform some logic and determine whether or not to shutdown the system. It does this by setting the shutdown_now signal high and then calling state <= next_state. My question is if the conditions become true that the shutdown_now signal is set (during clock cycle n) in a blocking manner before the state <= next_state line, will the state during clock cycle n+1 be SHUTDOWN or RUNNING? In other words, does the shutdown_now = 1'b1 line block across both state machines since the state signal is dependent on it through the next_state determination? enum {IDLE, RUNNING, SHUTDOWN} state, next_state; logic shutdown_now; // State machine (combinational) always_comb begin case (state) IDLE: next_state <= RUNNING; RUNNING: next_state <= shutdown ? SHUTDOWN : RUNNING; SHUTDOWN: next_state <= SHUTDOWN; default: next_state <= SHUTDOWN; endcase end // Sequential Behavior always_ff @ (posedge clk) begin // Some code here if (/*some condition) begin shutdown_now = 1'b0; end else begin shutdown_now = 1'b1; end state <= next_state; end

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