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  • Can you catch exceeded allocated memory error before it kills the script?

    - by kristovaher
    The thing is that I want to catch memory problems before they happen. I have a system that gets rows from database and casts the returned associative array to a variable, but I never know what the size of the database result is is or how much memory it will take once the database request is made. This means that my software can fail simply because memory is exceeded. But I want to avoid that somehow. One of the ways is to obviously make database requests that are smaller, but what if this is not possible or what if I do not know the size of data that is returned from database? Is it possible to 'catch' situations where memory use is exceeded in PHP? Something like this: $requestOk=memory_test(function(){ return doSomething(); }); if($requestOk){ // Memory seems fine // $requestOk now has the value from memory_test() function } else { // Function would have exceeded memory } I just find it problematic that my script can just die at any moment because of memory issues. From what I know, try-catch cannot be used here because it is a fatal error. Any help would be appreciated!

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  • Trying to make a plugin system in C++/Qt

    - by Pirate for Profit
    I'm making a task-based program that needs to have plugins. Tasks need to have properties which can be easily edited, I think this can be done with Qt's Meta-Object Compiler reflection capabilities (I could be wrong, but I should be able to stick this in a QtPropertyBrowser?) So here's the base: class Task : public QObject { Q_OBJECT public: explicit Task(QObject *parent = 0) : QObject(parent){} virtual void run() = 0; signals: void taskFinished(bool success = true); } Then a plugin might have this task: class PrinterTask : public Task { Q_OBJECT public: explicit PrinterTask(QObject *parent = 0) : Task(parent) {} void run() { Printer::getInstance()->Print(this->getData()); // fictional emit taskFinished(true); } inline const QString &getData() const; inline void setData(QString data); Q_PROPERTY(QString data READ getData WRITE setData) // for reflection } In a nutshell, here's what I want to do: // load plugin // find all the Tasks interface implementations in it // have user able to choose a Task and edit its specific Q_PROPERTY's // run the TASK It's important that one .dll has multiple tasks, because I want them to be associated by their module. For instance, "FileTasks.dll" could have tasks for deleting files, making files, etc. The only problem with Qt's plugin setup is I want to store X amount of Tasks in one .dll module. As far as I can tell, you can only load one interface per plugin (I could be wrong?). If so, the only possible way to do accomplish what I want is to create a FactoryInterface with string based keys which return the objects (as in Qt's Plug-And-Paint example), which is a terrible boilerplate that I would like to avoid. Anyone know a cleaner C++ plugin architecture than Qt's to do what I want? Also, am I safely assuming Qt's reflection capabilities will do what I want (i.e. able to edit an unknown dynamically loaded tasks' properties with the QtPropertyBrowser before dispatching)?

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  • Personalized UIView created with Interface Builder

    - by Malox
    I need to project a personalized UIView with a UIImageView and 3 UILabel. I need to allocate more of this view because I want put it into a UIScrollView. I would avoid to generate the view programatically because it's difficult and boring design it. My idea is to create a new class that extends UIView and design it with interface builder. For example my Personalized View code is like that: #import <UIKit/UIKit.h> @interface PersonalizedPreview : UIView { IBOutlet UIImageView *image; IBOutlet UILabel *first_label; IBOutlet UILabel *second_label; IBOutlet UILabel *third_label; } -(void) setImage:(UIImage *)image; @property (nonatomic, retain) IBOutlet UIImageView *image; @property (nonatomic, retain) IBOutlet UILabel *label; .... @end I would create an associated xib file for this view and initialize it simply specifing the xib file. Note that I don't want create a specific ViewController for this view and PersonalizedView is instantiate at runtime not when the app runs, moreover I don't know how many PersonalizedView I will instantiate, it depends on runtime execution. Anyone can help me? Thank you very much.

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  • TicTacToe strategic reduction

    - by NickLarsen
    I decided to write a small program that solves TicTacToe in order to try out the effect of some pruning techniques on a trivial game. The full game tree using minimax to solve it only ends up with 549,946 possible games. With alpha-beta pruning, the number of states required to evaluate was reduced to 18,297. Then I applied a transposition table that brings the number down to 2,592. Now I want to see how low that number can go. The next enhancement I want to apply is a strategic reduction. The basic idea is to combine states that have equivalent strategic value. For instance, on the first move, if X plays first, there is nothing strategically different (assuming your opponent plays optimally) about choosing one corner instead of another. In the same situation, the same is true of the center of the walls of the board, and the center is also significant. By reducing to significant states only, you end up with only 3 states for evaluation on the first move instead of 9. This technique should be very useful since it prunes states near the top of the game tree. This idea came from the GameShrink method created by a group at CMU, only I am trying to avoid writing the general form, and just doing what is needed to apply the technique to TicTacToe. In order to achieve this, I modified my hash function (for the transposition table) to enumerate all strategically equivalent positions (using rotation and flipping functions), and to only return the lowest of the values for each board. Unfortunately now my program thinks X can force a win in 5 moves from an empty board when going first. After a long debugging session, it became apparent to me the program was always returning the move for the lowest strategically significant move (I store the last move in the transposition table as part of my state). Is there a better way I can go about adding this feature, or a simple method for determining the correct move applicable to the current situation with what I have already done?

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  • UnicodeEncodeError: 'ascii' codec can't encode character [...]

    - by user1461135
    I have read the HOWTO on Unicode from the official docs and a full, very detailed article as well. Still I don't get it why it throws me this error. Here is what I attempt: I open an XML file that contains chars out of ASCII range (but inside allowed XML range). I do that with cfg = codecs.open(filename, encoding='utf-8, mode='r') which runs fine. Looking at the string with repr() also shows me a unicode string. Now I go ahead and read that with parseString(cfg.read().encode('utf-8'). Of course, my XML file starts with this: <?xml version="1.0" encoding="utf-8"?>. Although I suppose it is not relevant, I also defined utf-8 for my python script, but since I am not writing unicode characters directly in it, this should not apply here. Same for the following line: from __future__ import unicode_literals which also is right at the beginning. Next thing I pass the generated Object to my own class where I read tags into variables like this: xmldata.getElementsByTagName(tagName)[0].firstChild.data and assign it to a variable in my class. Now what perfectly works are those commands (obj is an instance of the class): for element in obj: print element And this command does work as well: print obj.__repr__() I defined __iter__() to just yield every variable while __repr__() uses the typical printf stuff: "%s" % self.varname Both commands print perfectly and can output the unicode character. What does not work is this: print obj And now I am stuck because this throws the dreaded UnicodeEncodeError: 'ascii' codec can't encode character u'\xfc' in position 47: So what am I missing? What am I doing wrong? I am looking for a general solution, I always want to handle strings as unicode, just to avoid any possible errors and write a compatible program. Edit: I also defined this: def __str__(self): return self.__repr__() def __unicode__(self): return self.__repr__() From documentation I got that this

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  • How to check for mip-map availability in OpenGL?

    - by Xavier Ho
    Recently I bumped into a problem where my OpenGL program would not render textures correctly on a 2-year-old Lenovo laptop with an nVidia Quadro 140 card. It runs OpenGL 2.1.2, and GLSL 1.20, but when I turned on mip-mapping, the whole screen is black, with no warnings or errors. This is my texture filter code: glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE); After 40 minutes of fiddling around, I found out mip-mapping was the problem. Turning it off fixed it: // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE); I get a lot of aliasing, but at least the program is visible and runs fine. Finally, two questions: What's the best or standard way to check if mip-mapping is available on a machine, aside from checking OpenGL versions? If mip-mapping is not available, what's the best work-around to avoid aliasing?

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  • HTTP Compression problems on IIS7

    - by Jonathan Wood
    I've spent quite a bit of time on this but seem to be going nowhere. I have a large page that I really want to speed up. The obvious place to start seems to be HTTP compression, but I just can't seem to get it to work for me. After considerable searching, I've tried several variations of the code below. It kind of works, but after refreshing the browser, the results seem to fall apart. They were turning to garbage when the page used caching. If I turn off caching, then the page seems right but I lose my CSS formatting (stored in a separate file) and get an error that an included JS file contains invalid characters. Most of the resources I've found on the Web were either very old or focused on accessing IIS directly. My page is running on a shared hosting account and I do not have direct access to IIS7, which it's running on. protected void Application_BeginRequest(object sender, EventArgs e) { // Implement HTTP compression if (Request["HTTP_X_MICROSOFTAJAX"] == null) // Avoid compressing AJAX calls { // Retrieve accepted encodings string encodings = Request.Headers.Get("Accept-Encoding"); if (encodings != null) { // Verify support for or gzip (deflate takes preference) encodings = encodings.ToLower(); if (encodings.Contains("gzip") || encodings == "*") { Response.Filter = new GZipStream(Response.Filter, CompressionMode.Compress); Response.AppendHeader("Content-Encoding", "gzip"); Response.Cache.VaryByHeaders["Accept-encoding"] = true; } else if (encodings.Contains("deflate")) { Response.Filter = new DeflateStream(Response.Filter, CompressionMode.Compress); Response.AppendHeader("Content-Encoding", "deflate"); Response.Cache.VaryByHeaders["Accept-encoding"] = true; } } } } Is anyone having better success with this?

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  • Vim: Making Auto-Completion Smarter

    - by Rafid K. Abdullah
    I use ctags, taglist, etc., to have auto completion in Vim. However, it is very limited compared to Visual Studio intellisense or Eclipse auto-completion. I am wondering whether it is possible to tune Vim to: Show auto-completion whenever . or - are typed. But only after some text that might be a variable (e.g. avoid showing auto completion after a number). Show function parameters when ( is typed. Stop removing the auto completion list when some delete all characters after . or -: When I enter a variable name, then press . or - to search for a certain member, I frequently have to delete all the characters I type after the . or -, but this makes Vim hide the auto completion list. I would like to keep it visible unless I press Esc. Showing related auto completion: When I type a variable and press ^X ^O, it usually shows me all the tags in the ctags file. I would like to have it showing only the tags related to the variable. Thanks for the help. EDIT: Some people are voting for this question, but no body seems to know the answer. So just wanted to mention that you don't have to provide a complete answer; partial answers to any of the mentioned points would be good also.

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  • PHP package manager

    - by Mathias
    Hey, does anyone know a package manager library for PHP (as e.g. apt or yum for linux distros) apart from PEAR? I'm working on a system which should include a package management system for module management. I managed to get a working solution using PEAR, but using the PEAR client for anything else than managing a PEAR installation is not really the optimal solution as it's not designed for that. I would have to modify/extend it (e.g. to implement actions on installation/upgrade or to move PEAR specific files like lockfiles away from the system root) and especially the CLI client code is quite messy and PHP4. So maybe someone has some suggestions for an alternative PEAR client library which is easy to use and extend (the server side has some nice implementations like Pirum and pearhub) for completely different package management systems written in PHP (ideally including dependency tracking and different channels) for some general ideas how to implement such a PM system (yes, I'm still tinkering with the idea of implementing such a system from scratch) I know that big systems like Magento and symfony use PEAR for their PM. Magento uses a hacked version of the original PEAR client (which I'd like to avoid), symfony's implementation seems quite integrated with the framework, but would be a good starting point to at least write the client from scratch. Anyway, if anybody has suggestions: please :)

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  • What if a large number of objects are passed to my SwingWorker.process() method?

    - by Trejkaz
    I just found an interesting situation. Suppose you have some SwingWorker (I've made this one vaguely reminiscent of my own): public class AddressTreeBuildingWorker extends SwingWorker<Void, NodePair> { private DefaultTreeModel model; public AddressTreeBuildingWorker(DefaultTreeModel model) { } @Override protected Void doInBackground() { // Omitted; performs variable processing to build a tree of address nodes. } @Override protected void process(List<NodePair> chunks) { for (NodePair pair : chunks) { // Actually the real thing inserts in order. model.insertNodeInto(parent, child, parent.getChildCount()); } } private static class NodePair { private final DefaultMutableTreeNode parent; private final DefaultMutableTreeNode child; private NodePair(DefaultMutableTreeNode parent, DefaultMutableTreeNode child) { this.parent = parent; this.child = child; } } } If the work done in the background is significant then things work well - process() is called with relatively small lists of objects and everything is happy. Problem is, if the work done in the background is suddenly insignificant for whatever reason, process() receives a huge list of objects (I have seen 1,000,000, for instance) and by the time you process each object, you have spent 20 seconds on the Event Dispatch Thread, exactly what SwingWorker was designed to avoid. In case it isn't clear, both of these occur on the same SwingWorker class for me - it depends on the input data, and the type of processing the caller wanted. Is there a proper way to handle this? Obviously I can intentionally delay or yield the background processing thread so that a smaller number might arrive each time, but this doesn't feel like the right solution to me.

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  • Flex 3 - Image flickers at first load

    - by BS_C3
    Hello Community! I have an application with different components that are accessible through a viewstack in the main application. The main application looks like that: <Application> <Viewstack> <myComponent1/> <myComponent2/> <myComponent3/> . . . </Viewstack> </Application> In myComponent1, I have a horizontalList where the user can select a product. In myComponent2, I have 2 containers inside the component. A left container with a larger image of the product selected in myComponent1 and a right container with all characteristics of the product. Both containers have an embed background image. When I select a product in myComponent1, the application displays myComponent2. When the component is displayed, I first see the page without the large image of the product, then both containers flickers and the product image is displayed. How could I avoid this flickering? It's really annoying _< Thanks in advance for your help =) Regards. BS_C3

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  • MySQL Database Design with Internationalization

    - by Some name
    Hello, I'm going to start work on a medium sized application, and i'm planning it's db design. One thing that I'm not sure about is this. I will have many tables which will need internationalization, such as: "membership_options, gender_options, language_options etc" Each of these tables will share common i18n fields, like: "title, alternative_title, short_description, description" In your opinion which is the best way to do it? Have an i18n table with the same fields for each of the tables that will need them? or do something like: Membership table Gender table ---------------- -------------- id | created_at id | created_at 1 - 22.03.2001 1 - 14.08.2002 2 - 22.03.2001 2 - 14.08.2002 General translation table ------------------------- record_id | table_name | string_name | alternative_title| .... |id_language 1 - membership regular null 1 (english) 1 - membership normale null 2 (italian) 1 - gender man null 1(english) 1 -gender uomo null 2(italian) This would avoid me repeating something like: membership_translation table ----------------------------- membership_id | name | alternative_title | id_lang 1 regular null 1 1 normale null 2 gender_translation table ----------------------------- gender_id | name | alternative_title | id_lang 1 man null 1 1 uomo null 2 and so on, so i would probably reduce the number of db tables, but i'm not sure about performance.I'm not much of a DB designer, so please let me know.

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  • jQuery's draggable grid

    - by Art
    It looks like that the 'grid' option in the constructor of Draggable is relatively bound to the original coordinates of the element being dragged - so simply put, if you have three draggable divs with their top set respectively to 100, 200, 254 pixels relative to their parent: <div class="parent-div" style="position: relative;"> <div id="div1" class="draggable" style="top: 100px; position: absolute;"></div> <div id="div2" class="draggable" style="top: 200px; position: absolute;"></div> <div id="div3" class="draggable" style="top: 254px; position: absolute;"></div> </div> Adn all of them are getting enabled for dragging with 'grid' set to [1, 100]: draggables = $('.draggable'); $.each(draggables, function(index, elem) { $(elem).draggable({ containment: $('#parent-div'), opacity: 0.7, revert: 'invalid', revertDuration: 300, grid: [1, 100], refreshPositions: true }); }); Problem here is that as soon as you drag div3, say, down, it's top is increased by 100, moving it to 354px instead of being increased by just mere 46px (254 + 46 = 300), which would get it to the next stop in the grid - 300px, if we are looking at the parent-div as a point of reference and "grid holder". I had a look at the draggable sources and it seem to be an in-built flaw - they just do all the calculations relative to the original position of the draggable element. I would like to avoid monkey-patching the code of draggable library and what I am really looking for here is the way how to make the Draggable calculate the grid positions relative to containing parent. However if monkey-patching is unavoidable, I guess I'll have to live with it. Thanks!

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  • Polling servers at the same port - Threads and Java

    - by John
    Hi there. I'm currently busy working on an IP ban tool for the early versions of Call of Duty 1. (Apparently such a feature wasn't implemented in these versions). I've finished a single threaded application but it won't perform well enough for multiple servers, which is why I am trying to implement threading. Right now, each server has its own thread. I have a Networking class, which has a method; "GetStatus" -- this method is synchronized. This method uses a DatagramSocket to communicate with the server. Since this method is static and synchronized, I shouldn't get in trouble and receive a whole bunch of "Address already in use" exceptions. However, I have a second method named "SendMessage". This method is supposed to send a message to the server. How can I make sure "SendMessage" cannot be invoked when there's already a thread running in "GetStatus", and the other way around? If I make both synchronized, I will still get in trouble if Thread A is opening a socket on Port 99999 and invoking "SendMessage" while Thread B is opening a socket on the same port and invoking "GetStatus"? (Game servers are usually hosted on the same ports) I guess what I am really after is a way to make an entire class synchronized, so that only one method can be invoked and run at a time by a single thread. Hope that what I am trying to accomplish/avoid is made clear in this text. Any help is greatly appreciated.

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  • Custom permalinks switching function. Please check this logic...

    - by Scott B
    I've got a setting in my theme options panel to allow the user to switch the permalinks setting to support friendly URLs. I'm only allowing /%postname%/ and /%postname%.html as options. I don't want to be triggering an htaccess rewrite everytime someone accesses a page on the site or views theme options, so I'm trying to code this to avoid that. I've got an input field in theme options that's called $myTheme_permalinks. The default value for this is "/%postname%/" but the user can also change it to "/%postname%.html" Here's the code at the top of theme options to handle this setting. Does this look sound? if(get_option('myTheme_permalinks') =="/%postname%/" && get_option('permalink_structure') !== "/%postname%/" || !get_option('myTheme_permalinks')) { require_once(ABSPATH . '/wp-admin/includes/misc.php'); require_once(ABSPATH . '/wp-admin/includes/file.php'); global $wp_rewrite; $wp_rewrite->set_permalink_structure('/%postname%/'); $wp_rewrite->flush_rules(); update_option('permalink_structure','/%postname%/'); update_option('myTheme_permalinks','/%postname%/'); } else if (get_option('myTheme_permalinks') =="/%postname%.html" && get_option('permalink_structure') !== "/%postname%.html" && ) { require_once(ABSPATH . '/wp-admin/includes/misc.php'); require_once(ABSPATH . '/wp-admin/includes/file.php'); global $wp_rewrite; $wp_rewrite->set_permalink_structure('/%postname%.html'); $wp_rewrite->flush_rules(); update_option('permalink_structure','/%postname%.html'); }

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  • Java applet loading images from external jars

    - by Mathias
    I have a jar on a server, and users should be able to develop extensions for it. Therefore the jars main class should be extended and some resources should be added to a second user created jar which will be loaded from another server or locally. Now I have problems accessing the resources (images) from the user loaded jars. Heres is the structure: My Server: game.jar containing game.class images.class ... image1.png (...) Local: user.jar containing: user.class extends game userimage.png The extension is loaded via Greasemonkey, it modifies the "archive" attribute to "/home/username/user.jar, game.jar" and the "code" attribute to "user.class". The user should be able to overwrite already defined images. If the image does not exist in game.jar, it is loaded correctly from user.jar. But the images loaded early in the game are always loaded from the game.jar, others seem to be overwritten correctly by the user. Is there a way to make sure they are always loaded in the correct order? This might be because of some caching mechanism. Because Greasemonkey removes the game from the page, changes the archive and code and reinsert it, the game is loaded without a mod for a brief second. In that time, images are loaded as expected from game jar, but those are the ones not being overwritable by the user. But how to avoid it? Another thing: If I overwrite the "run" method in user.class, the game is unable to load any image at all. Not from the user.jar and not from the game.jar. Java doesn't find the image, as the URL object "getClass().getResource(imagename)" returns with null. I tried to overwrite the image.class, but that doesn't fix the problem, unless I overwrite every class from game.class involved into calling the image.class

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  • Haml Inherit Templates

    - by kjfletch
    I'm using Haml (Haml/Sass 3.0.9 - Classy Cassidy) stand-alone to generate static HTML. I want to create a shared layout template that all my other templates inherit. Layout.haml %html %head %title Test Template %body .Content Content.haml SOMEHOW INHERIT Layout.haml SOMEHOW Change the title of the page "My Content". %p This is my content To produce: Content.html <html> <head> <title>My Content</title> </head> <body> <div class="Content"> <p>This is my content</p> </div> </body> </html> But this doesn't seem possible. I have seen the use of rendering partials when using Haml with Rails but can't find any solution when using Haml stand-alone. Having to put the layout code in all of my templates would be a maintenance nightmare; so my question is how do I avoid doing this? Is there a standard way to solve this problem? Have I missed something fundamental?

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  • EF/LINQ: Where() against a property of a subtype

    - by ladenedge
    I have a set of POCOs, all of which implement the following simple interface: interface IIdObject { int Id { get; set; } } A subset of these POCOs implement this additional interface: interface IDeletableObject : IIdObject { bool IsDeleted { get; set; } } I have a repository hierarchy that looks something like this: IRepository<T <: BasicRepository<T <: ValidatingRepository<T (where T is IIdObject) I'm trying to add a FilteringRepository to the hierarchy such that all of the POCOs that implement IDeletableObject have a Where(p => p.IsDeleted == false) filter applied before any other queries take place. My goal is to avoid duplicating the hierarchy solely for IDeletableObjects. My first attempt looked like this: public override IQueryable<T> Query() { return base.Query().Where(t => ((IDeletableObject)t).IsDeleted == false); } This works well with LINQ to Objects, but when I switch to an EF backend I get: "LINQ to Entities only supports casting Entity Data Model primitive types." I went on to try some fancier parameterized solutions, but they ultimately failed because I couldn't make T covariant in the following case for some reason I don't quite understand: interface IQueryFilter<out T> // error { Expression<Func<T, bool>> GetFilter(); } I'd be happy to go into more detail on my more complicated solutions if it would help, but I think I'll stop here for now in hope that someone might have an idea for me to try. Thanks very much in advance!

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  • [C#] Three System.Drawing methods manifest slow drawing or flickery: Solutions? or Other Options?

    - by Luke Mcneice
    Hi all, I am doing a little graphing via the System.Drawing and im having a few problems. I'm holding data in a Queue and i'm drawing(graphing) out that data onto three picture boxes this method fills the picture box then scrolls the graph across. so not to draw on top of the previous drawings (and graduly looking messier) i found 2 solutions to draw the graph. Call plot.Clear(BACKGOUNDCOLOR) before the draw loop [block commented] although this causes a flicker to appear from the time it takes to do the actual drawing loop. call plot.DrawLine(channelPen[5], j, 140, j, 0); just before each drawline [commented] although this causes the drawing to start ok then slow down very quickly to a crawl as if a wait command had been placed before the draw command. Here is the Code for reference: /*plotx.Clear(BACKGOUNDCOLOR) ploty.Clear(BACKGOUNDCOLOR) plotz.Clear(BACKGOUNDCOLOR)*/ for (int j = 1; j < 599; j++) { if (j > RealTimeBuffer.Count - 1) break; QueueEntity past = RealTimeBuffer.ElementAt(j - 1); QueueEntity current = RealTimeBuffer.ElementAt(j); if (j == 1) { //plotx.DrawLine(channelPen[5], 0, 140, 0, 0); //ploty.DrawLine(channelPen[5], 0, 140, 0, 0); //plotz.DrawLine(channelPen[5], 0, 140, 0, 0); } //plotx.DrawLine(channelPen[5], j, 140, j, 0); plotx.DrawLine(channelPen[0], j - 1, (((past.accdata.X - 0x7FFF) / 256) + 64), j, (((current.accdata.X - 0x7FFF) / 256) + 64)); //ploty.DrawLine(channelPen[5], j, 140, j, 0); ploty.DrawLine(channelPen[1], j - 1, (((past.accdata.Y - 0x7FFF) / 256) + 64), j, (((current.accdata.Y - 0x7FFF) / 256) + 64)); //plotz.DrawLine(markerPen, j, 140, j, 0); plotz.DrawLine(channelPen[2], j - 1, (((past.accdata.Z - 0x7FFF) / 256) + 94), j, (((current.accdata.Z - 0x7FFF) / 256) + 94)); } Is there any tricks to avoid these overheads? If not would there be any other/better solutions?

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  • How to create view model without sorting collections in memory.

    - by Chevex
    I have a view model (below). public class TopicsViewModel { public Topic Topic { get; set; } public Reply LastReply { get; set; } } I want to populate an IQueryable<TopicsViewModel> with values from my IQueryable<Topic> collection and IQueryable<Reply> collection. I do not want to use the attached entity collection (i.e. Topic.Replies) because I only want the last reply for that topic and doing Topic.Replies.Last() loads the entire entity collection in memory and then grabs the last one in the list. I am trying to stay in IQueryable so that the query is executed in the database. I also don't want to foreach through topics and query replyRepository.Replies because looping through IQueryable<Topic> will start the lazy loading. I'd prefer to build one expression and have all the leg work done in the lower layers. I have the following: IQueryable<TopicsViewModel> topicsViewModel = from x in topicRepository.Topics from y in replyRepository.Replies where y.TopicID == x.TopicID orderby y.PostedDate ascending select new TopicsViewModel { Topic = x, LastReply = y }; But this isn't working. Any ideas how I can populate an IQueryable or IEnumerable of TopicsViewModel so that it queries the database and grabs topics and that topic's last reply? I am trying really hard to avoid grabbing all replies related to that topic. I only want to grab the last reply. Thank you for any insight you have to offer.

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  • How can I shared controller logic in ASP.NET MVC for 2 controllers, where they are overriden

    - by AbeP
    Hello, I am trying to implement user-friendly URLS, while keeping the existing routes, and was able to do so using the ActionName tag on top of my controller (http://stackoverflow.com/questions/436866/can-you-overload-controller-methods-in-asp-net-mvc) I have 2 controllers: ActionName("UserFriendlyProjectIndex")] public ActionResult Index(string projectName) { ... } public ActionResult Index(long id) { ... } Basically, what I am trying to do is I store the user-friendly URL in the database for each project. If the user enters the URL /Project/TopSecretProject/, the action UserFriendlyProjectIndex gets called. I do a database lookup and if everything checks out, I want to apply the exact same logic that is used in the Index action. I am basically trying to avoid writing duplicate code. I know I can separate the common logic into another method, but I wanted to see if there is a built-in way of doing this in ASP.NET MVC. Any suggestions? I tried the following and I go the View could not be found error message: [ActionName("UserFriendlyProjectIndex")] public ActionResult Index(string projectName) { var filteredProjectName = projectName.EscapeString().Trim(); if (string.IsNullOrEmpty(filteredProjectName)) return RedirectToAction("PageNotFound", "Error"); using (var db = new PIMPEntities()) { var project = db.Project.Where(p => p.UserFriendlyUrl == filteredProjectName).FirstOrDefault(); if (project == null) return RedirectToAction("PageNotFound", "Error"); return View(Index(project.ProjectId)); } } Here's the error message: The view 'UserFriendlyProjectIndex' or its master could not be found. The following locations were searched: ~/Views/Project/UserFriendlyProjectIndex.aspx ~/Views/Project/UserFriendlyProjectIndex.ascx ~/Views/Shared/UserFriendlyProjectIndex.aspx ~/Views/Shared/UserFriendlyProjectIndex.ascx Project\UserFriendlyProjectIndex.spark Shared\UserFriendlyProjectIndex.spark I am using the SparkViewEngine as the view engine and LINQ-to-Entities, if that helps. thank you!

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  • How to efficiently store and update binary data in Mongodb?

    - by Rocketman
    I am storing a large binary array within a document. I wish to continually add bytes to this array and sometimes change the value of existing bytes. I was looking for some $append_bytes and $replace_bytes type of modifiers but it appears that the best I can do is $push for arrays. It seems like this would be doable by performing seek-write type operations if I had access somehow to the underlying bson on disk, but it does not appear to me that there is anyway to do this in mongodb (and probably for good reason). If I were instead to just query this binary array, edit or add to it, and then update the document by rewriting the entire field, how costly will this be? Each binary array will be on the order of 1-2MB, and updates occur once every 5 minutes and across 1000s of documents. Worse, yet there is no easy way to spread these out (in time) and they will usually be happening close to one another on the 5 minute intervals. Does anyone have a good feel for how disastrous this will be? Seems like it would be problematic. An alternative would be to store this binary data as separate files on disk, implement a thread pool to efficiently manipulate the files on disk, and reference the filename from my mongodb document. (I'm using python and pymongo so I was looking at pytables). I'd prefer to avoid this though if possible. Is there any other alternative that I am overlooking here? Thanks in advnace.

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  • Why there is no scoped locks for multiple mutexes in C++0x or Boost.Thread?

    - by Vicente Botet Escriba
    C++0x thread library or Boost.thread define non-member variadic template function that lock all lock avoiding dead lock. template <class L1, class L2, class... L3> void lock(L1&, L2&, L3&...); While this function avoid help to deadlock, the standard do not includes the associated scoped lock to write exception safe code. { std::lock(l1,l2); // do some thing // unlock li l2 exception safe } That means that we need to use other mechanism as try-catch block to make exception safe code or define our own scoped lock on multiple mutexes ourselves or even do that { std::lock(l1,l2); std::unique_lock lk1(l1, std::adopted); std::unique_lock lk2(l2, std::adopted); // do some thing // unlock li l2 on destruction of lk1 lk2 } Why the standard doesn't includes a scoped lock on multiple mutexes of the same type, as for example { std::array_unique_lock<std::mutex> lk(l1,l2); // do some thing // unlock l1 l2 on destruction of lk } or tuples of mutexes { std::tuple_unique_lock<std::mutex, std::recursive_mutex> lk(l1,l2); // do some thing // unlock l1 l2 on destruction of lk } Is there something wrong on the design?

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  • MySQL get point in time totals from related tables

    - by batfastad
    Hi everyone We have an order book and invoicing system and I've been tasked with trying to output monthly rolling totals from these tables. But I don't know really where to start with this. I think there's some SQL syntax that I don't even know about yet. I'm familiar with INNER/LEFT/JOINS and GROUP BY etc but grouping by date is confusing since I don't know how to limit the data to only the current date that's being grouped by at that point. I think this will involve joining the tables to themselves or possibly a sub-select. I always thought it best to avoid sub-selects apart from when absolutely necessary. Basically the system has 3 tables orders: order_id, currency, order_stamp orders_lines: order_line_id, invoice_id, order_id, price invoices: invoice_id, invoice_stamp order_stamp and invoice_stamp are UTC unix timestamps stored as integers, not MySQL timestamps. I'm trying to get a listing by year/month showing the total of current unbilled orders (sum of price), at that point in time. Current orders are ones where order_stamp is less than or equal to 00:00 on the 1st of the month. Unbilled orders are ones where invoice_stamp is null or invoice_stamp is greater than 00:00 on the 1st of the month. At that point in time there may not be a related invoice yet and invoice_id might be null. Anyone got any suggestions on what I should join to what and what I need to group by? Cheers, B

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  • Practical non-image based CAPTCHA approaches?

    - by Jeff Atwood
    It looks like we'll be adding CAPTCHA support to Stack Overflow. This is necessary to prevent bots, spammers, and other malicious scripted activity. We only want human beings to post or edit things here! We'll be using a JavaScript (jQuery) CAPTCHA as a first line of defense: http://docs.jquery.com/Tutorials:Safer_Contact_Forms_Without_CAPTCHAs The advantage of this approach is that, for most people, the CAPTCHA won't ever be visible! However, for people with JavaScript disabled, we still need a fallback and this is where it gets tricky. I have written a traditional CAPTCHA control for ASP.NET which we can re-use. However, I'd prefer to go with something textual to avoid the overhead of creating all these images on the server with each request. I've seen things like.. ASCII text captcha: \/\/(_)\/\/ math puzzles: what is 7 minus 3 times 2? trivia questions: what tastes better, a toad or a popsicle? Maybe I'm just tilting at windmills here, but I'd like to have a less resource intensive, non-image based <noscript> compatible CAPTCHA if possible. Ideas?

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