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• PHP: Profiling code and strict environment ~ Improving my coding

  - by DavidYell

  I would like to update my local working environment to be stricter in an effort to improve my code. I know that my code is okay, but as with most things there is always room for improvement. I use XAMPP on my local machine, for simplicities sake Apache Friends XAMPP (Basic Package) version 1.7.2 So I've updated my php.ini : error_reporting to be E_ALL | E_STRICT to help with the code standard. I've also enabled the XDebug extension zend_extension = "C:\xampp\php\ext\php_xdebug.dll" which seems to be working, having tested some broken code and got the nice standard orange error notice. However, having read this question, http://stackoverflow.com/questions/133686/what-is-the-best-way-to-profile-php-code and enabled the profiler, I cannot seem to create a cachegrind file. Many of the guides that I've looked at seem to think you need to install XDebug in XAMPP which leads me to think they are out of date, as XDebug is bundled with XAMPP these days. So I would appreciate it if anyone can help point me in the right direction with both configuring XDebug to output grind files, and or just a great set of default settings for the XDebug config in XAMPP. Seems there is very little documentation to go on. If people have tips on integrating these tools with Netbeans, that would be awesomesauce. I'm happy to get suggestions on other things that I can do to help tighten up my php code, both syntactically and performance wise Thanks, and apologies for the rambling question(s)! Ninja edit I should menion that I'm using named vhosts as my Apache configuration, which I think is why running XDebug on port 9000 isn't working for me. I guess I'd need to edit my vhost to include port 9000

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• Adding and removing elements efficiently from Collection object

  - by user569125

  Hi, Below coding is the working sample,but still i am not happy with this code with related to performancewise.Please have a look and let me know if any better approach is there.Thanks in advance. Adding items to the arraylist object String resultItems[] = paging.getMoveLeftArray().split(","); String fields[]={"id","name","name1"}; leftObj=new ArrayList(); for(int i=0;i<resultItems.length;i++){ //below line mea TestVO bean=new TestVO(); String resultItem = resultItems[i]; String idANDname[] = resultItem.split("@"); String id = idANDname[0]; // name or id should not contain "-" String name[] = idANDname[1].split("-"); //values and fileds are always having same length for(int j=0;j<name.length;j++) { PropertyUtils.setProperty(bean, fields[j], name[j]); } leftObj.add(bean); } Removing items from the arraylist object:availableList contains all the TestVO objects: String []removeArray=paging.getMoveRightArray().split(","); tempList=new CopyOnWriteArrayList(); newTempList=new CopyOnWriteArrayList(); for(int i=0;i<availableList.size();i++){ boolean flag = false; TestVO tempObj = (TestVO )availableList.get(i); int id =(Integer)tempObj.getId(); // System.out.println("id value"+id); // availableList.get(i).getClass().getField(name); for(int j=0;j<removeArray.length;j++){ String resultItem = removeArray[j]; String idandname[] = resultItem.split("@"); for(int k=0;k<idandname.length;k++){ String ids[]=idandname[0].split("-"); if(id==Integer.parseInt(ids[0])){ flag = true; break; } } } if(flag){ tempList.add(tempObj); } else{ newTempList.add(tempObj); }

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• I seek a PDF paginator

  - by Cameron Laird

  More precisely, I need software that will allow me to consume existing PDF instances, decorate them with page numbers, or page-number-like writing, then write them back to the filesystem. I'll happily pay for an application, or program it myself. I almost certainly require the software run under Linux (Ubuntu, more specifically). iText comes close. iText certainly can read existing PDF instances. While iText is, for this purpose, only a library, and requires me to program a tiny amount to specify where on the page the numbers should appear, I'm happy to do that. I hesitate with iText only because the latest iText license is a headache at certain government agencies (in practice, I'd probably request and pay for a special license), and because, over the last few years, I've observed cases where iText doesn't appear to keep up with the standard, that is, it has more troubles than I expect reading PDFs observed "in the wild". Similarly, every other possibility I know has at least one difficulty: ReportLab would likely require a disproportionate licensing fee for the small value it provides in this situation, and so on. This application requires no particular sophistication with Unicode, fonts, ... I recognize there are plenty of executables and libraries that do some or all of what I require. I welcome any tips on software that is reliable, generally current with PDF practice, flexible/programmable/configurable/..., and "automatable". In the absence of any new insight, I'll likely go with a specific open-source library I don't want to mention now for which I've already contracted enhancements, or perhaps revisit iText.

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• .NET Web Service hydrate custom class

  - by row1

  I am consuming an external C# Web Service method which returns a simple calculation result object like this: [Serializable] public class CalculationResult { public string Name { get; set; } public string Unit { get; set; } public decimal? Value { get; set; } } When I add a Web Reference to this service in my ASP .NET project Visual Studio is kind enough to generate a matching class so I can easily consume and work with it. I am using Castle Windsor and I may want to plug in other method of getting a calculation result object, so I want a common class CalculationResult (or ICalculationResult) in my solution which all my objects can work with, this will always match the object returned from the external Web Service 1:1. Is there anyway I can tell my Web Service client to hydrate a particular class instead of its generated one? I would rather not do it manually: foreach(var fromService in calcuationResultsFromService) { ICalculationResult calculationResult = new CalculationResult() { Name = fromService.Name }; yield return calculationResult; } Edit: I am happy to use a Service Reference type instead of the older Web Reference.

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• XSLT creating a table with varying amount of columns

  - by H4mm3rHead

  Hi, I have a RSS feed i need to display in a table (its clothes from a webshop system). The images in the RSS vary in width and height and I want to make a table that shows them all. First off i would be happy just to show all of the items in 3 columns, but further down the road i need to be able to specify through a parameter the amount of columns in my table. I run into a problem showing the tr tag, and making it right, this is my Code so far: <xsl:template match="item"> <xsl:choose> <xsl:when test="position() mod 3 = 0 or position()=1"> <tr> <td> <xsl:value-of select="title"/> </td> </tr> </xsl:when> <xsl:otherwise> <td> <xsl:value-of select="title"/> </td> </xsl:otherwise> </xsl:choose> </xsl:template> In RSS all "item" tags are on the same level in the xml, and thus far i need only the title shows. Thr problem seems to be that i need to specify the start tag as well as the end tag of the tr element, and cant get all 3 elements into it, anyone know how to do this?

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• Suggested (simple) approach for drawing large numbers of visual elements in WPF?

  - by Ender

  I'm writing an interface that features a large (~50000px width) "canvas"-type area that is used to display a lot of data in a fairly novel way. This involves lots of lines, rectangles, and text. The user can scroll around to explore the entire canvas. At the moment I'm just using a standard Canvas panel with various Shapes placed on it. This is nice and easy to do: construct a shape, assign some coordinates, and attach it to the Canvas. Unfortunately, it's pretty slow (to construct the children, not to do the actual rendering). I've looked into some alternatives, it's a bit intimidating. I don't need anything fancy - just the ability to efficiently construct and place objects in a coordinate plane. If all I get are lines, colored rectangles, and text, I'll be happy. Do I need Geometry instances inside of Geometry Groups inside of GeometryDrawings inside of some Panel container? Note: I'd like to include text and graphics (i.e. colored rectangles) in the same space, if possible.

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• Scope of "library" methods

  - by JS

  Hello, I'm apparently laboring under a poor understanding of Python scoping. Perhaps you can help. Background: I'm using the 'if name in "main"' construct to perform "self-tests" in my module(s). Each self test makes calls to the various public methods and prints their results for visual checking as I develop the modules. To keep things "purdy" and manageable, I've created a small method to simplify the testing of method calls: def pprint_vars(var_in): print("%s = '%s'" % (var_in, eval(var_in))) Calling pprint_vars with: pprint_vars('some_variable_name') prints: some_variable_name = 'foo' All fine and good. Problem statement: Not happy to just KISS, I had the brain-drizzle to move my handy-dandy 'pprint_vars' method into a separate file named 'debug_tools.py' and simply import 'debug_tools' whenever I wanted access to 'pprint_vars'. Here's where things fall apart. I would expect import debug_tools foo = bar debug_tools.pprint_vars('foo') to continue working its magic and print: foo = 'bar' Instead, it greets me with: NameError: name 'some_var' is not defined Irrational belief: I believed (apparently mistakenly) that import puts imported methods (more or less) "inline" with the code, and thus the variable scoping rules would remain similar to if the method were defined inline. Plea for help: Can someone please correct my (mis)understanding of scoping regards imports? Thanks, JS

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• DataSets to POCOs - an inquiry regarding DAL architecture

  - by alexsome

  Hello all, I have to develop a fairly large ASP.NET MVC project very quickly and I would like to get some opinions on my DAL design to make sure nothing will come back to bite me since the BL is likely to get pretty complex. A bit of background: I am working with an Oracle backend so the built-in LINQ to SQL is out; I also need to use production-level libraries so the Oracle EF provider project is out; finally, I am unable to use any GPL or LGPL code (Apache, MS-PL, BSD are okay) so NHibernate/Castle Project are out. I would prefer - if at all possible - to avoid dishing out money but I am more concerned about implementing the right solution. To summarize, there are my requirements: Oracle backend Rapid development (L)GPL-free Free I'm reasonably happy with DataSets but I would benefit from using POCOs as an intermediary between DataSets and views. Who knows, maybe at some point another DAL solution will show up and I will get the time to switch it out (yeah, right). So, while I could use LINQ to convert my DataSets to IQueryable, I would like to have a generic solution so I don't have to write a custom query for each class. I'm tinkering with reflection right now, but in the meantime I have two questions: Are there any problems I overlooked with this solution? Are there any other approaches you would recommend to convert DataSets to POCOs? Thanks in advance.

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• Tips on designing a .NET API for future use with F#

  - by Drew Noakes

  I'm in the process of designing a .NET API to allow developers to create RoboCup agents for the 3D simulated soccer league. I'm pretty happy with how the API work with C# code, however I would like to use this project to improve my F# skill (which is currently based on reading rather than practice). So I would like to ask what kinds of things I should consider when designing an API that is to be consumed by both C# and F# code. Some points. I make fairly heavy use of matrix and vector math. These are currently immutable classes/structs. The API currently defines a few interfaces with the consumer implements (eg: IAgent), using instances of their implementations (eg: MyAgent) to construct other API classes (eg: new Client(myAgent)). The API fires events. The API exposes a few delegate types. The API includes several enums. I'd like to release a version of the API as soon as possible and don't want to make major changes to it later if I realise it's too difficult to work with from F#. Any advice is appreciated.

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• Encapsulate update method inside of object or have method which accepts an object to update

  - by Tom

  Hi, I actually have 2 questions related to each other: I have an object (class) called, say MyClass which holds data from my database. Currently I have a list of these objects ( List < MyClass ) that resides in a singleton in a "communal area". I feel it's easier to manage the data this way and I fail to see how passing a class around from object to object is beneficial over a singleton (I would be happy if someone can tell me why). Anyway, the data may change in the database from outside my program and so I have to update the data every so often. To update the list of the MyClass I have a method called say, Update, written in another class which accepts a list of MyClass. This updates all the instances of MyClass in the list. However would it be better instead to encapulate the Update() method inside the MyClass object, so instead I would say foreach(MyClass obj in MyClassList) { obj.update(); } What is a better implementation and why? The update method requires a XML reader. I have written an XML reader class which is basically a wrapper over the standard XML reader the language natively provides which provides application specific data collection. Should the XML reader class be in anyway in the "inheritance path" of the MyClass object - the MyClass objects inherits from the XML reader because it uses a few methods. I can't see why it should. I don't like the idea of declaring an instance of the XML Reader class inside of MyClass and an MyClass object is meant to be a simple "record" from the database and I feel giving it loads of methods, other object instances is a bit messy. Perhaps my XML reader class should be static but C#'s native XMLReader isn't static.? Any comments would be greatly appreciated Thanks Thomas

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• Someone selling my GPL theme

  - by PaKK

  I'm having a tough time trying to figure out the best way to handle this. I've created a few themes last year, released them under a GPL license, and pretty much forgot about them. My goal was to put them out publicly as samples of my work. I've recently come across a site and was shocked they are selling one of my themes among several other themes (not mine) and other support and package systems. Anyway needless to say I'm not happy about this. I did not intend for those themes to be sold, and if they are to be sold, at least I would expect a percentage of those sales. I contacted the website asking how many they sold and that I'm the author of one of the themes they were selling. I eventually received a reply that my theme is a GPL theme and that this license allows them to sell it without compensation to me. WTF? Just the way the reply was worded pissed me off. There is no way to comment on the site to inform possible buyers that those themes can be downloaded from my site. What can I do about this? I realize now it was a bad choice to release them under that license. Is it possible to take back the theme from public distribution or is it out forever. Can I change it from GPL to another license at this point? Will that be sufficient to stop the sale of my theme in the future? Any insights are appreciated.

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• writing CMS in ZEND

  - by Neoman

  Hello guys, I'm trying to write my own CMS using Zend framework and I created modular structure. I have modules like 'news', 'blog' and etc. Also I have "admin" module which has different layout and this is like the administrator panel where admin can edit all the content and etc. But the problem is that I'm looking for the best practice and solution to solve the problem. I don't like the idea that my admin module will have a lot of controllers which will be for administer all the other modules. So I want to ask you all, maybe you have some tuts or just have an advice how to implement admin module separated from other modules as much as it can be done. Because I just want to copy one module for example from one project to another and I want it will work same. I don't want to search the right admin controller, view or something like this in admin module and copy this part seperatelly into new admin module. Hope the question and situation is clear enough and I will be happy to hear any advice or see any tutorials how to do it. Thanks guys!

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• Add two 32-bit integers in Assembler for use in VB6

  - by Emtucifor

  I would like to come up with the byte code in assembler (assembly?) for Windows machines to add two 32-bit longs and throw away the carry bit. I realize the "Windows machines" part is a little vague, but I'm assuming that the bytes for ADD are pretty much the same in all modern Intel instruction sets. I'm just trying to abuse VB a little and make some things faster. So... if the string "8A4C240833C0F6C1E075068B442404D3E0C20800" is the assembly code for SHL that can be "injected" into a VB6 program for a fast SHL operation expecting two Long parameters (we're ignoring here that 32-bit longs in VB6 are signed, just pretend they are unsigned), what is the hex string of bytes representing assembler instructions that will do the same thing to return the sum? The hex code above for SHL is, according to the author: mov eax, [esp+4] mov cl, [esp+8] shl eax, cl ret 8 I spit those bytes into a file and tried unassembling them in a windows command prompt using the old debug utility, but I figured out it's not working with the newer instruction set because it didn't like EAX when I tried assembling something but it was happy with AX. I know from comments in the source code that SHL EAX, CL is D3E0, but I don't have any reference to know what the bytes are for instruction ADD EAX, CL or I'd try it. I tried flat assembler and am not getting anything I can figure out how to use. I used it to assemble the original SHL code and got a very different result, not the same bytes. Help?

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• PhpBB3: adding background to specific php generated text input without affecting the other text inputs

  - by user1780055

  I have created a custom PhpBB3 style and desperately since a few hours tried to add a background image to a specific comment text area. With firebug I checked if the comment text area had a class and it does, so I tried some css variations and finally tried: sn-inputComment { background: url("{T_THEME_PATH}/images/pencil.png") repeat-x left top #FFFFFF;} { I also tried to find and manipulate the php generated text area but no success. Non of my methods worked. I will provide you all with a tinylink url to my forum with a test user and password access. User: test Password: 123456 url: http://tinyurl.com/9yqpxdb Now when you are logged in you should be redirected to the correct url and you will see a a few text boxes with "Write a comment...". I would be very happy if you could tell me what I did wrong, why im not able to add a background to the text input without having my search boxes and "what is on your mind box" affected. I appreciate your time and hope that this can be somehow solved. Sincerely, Daniel

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• UIAlertView choice causing resignFirstResponder to fail

  - by Chazbot

  Hi everyone. I'm having a similar issue to Anthony Chan's question, and after trying every suggested solution, I'm still stuck. Somehow, only after interacting with my UIAlertView, I'm unable to dismiss the keyboard in another view of my app. It's as though the Alert is breaking my UITextField's ability to resignFirstResponder. Below I instantiate my UIAlertView, which then calls its didDismissWIthButtonIndex method. Then, I call the showInfo method, which loads another UIViewController. UIAlertView *emailFailAlert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"error message text." delegate:self cancelButtonTitle:@"Not now" otherButtonTitles:@"Settings", nil]; [emailFailAlert setTag:2]; [emailFailAlert show]; [emailFailAlert release]; Once the 'Settings' option is pressed, I'm calling this method: - (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex { if ([alertView tag] == 2) { if (buttonIndex == 1){ [self showInfo:nil]; } } } My showInfo method loads the other ViewController, via the code below: - (IBAction)showInfo:(id)sender { FlipsideViewController *fscontroller = [[FlipsideViewController alloc] initWithNibName:@"FlipsideView" bundle:nil]; fscontroller.delegate = self; fscontroller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal; [self presentModalViewController:fscontroller animated:YES]; [fscontroller release]; } Upon clicking any textField in this Flipside VC, I'm unable to dismiss the keyboard as I normally can with - (BOOL)textFieldShouldReturn:(UITextField *)textField, and [textField resignFirstResponder]. I've omitted this code bc this question is getting long, but I'm happy to post if necessary. The interesting part is that if I comment out the [self showInfo:nil] call made when the button is clicked and call it by clicking a test button (outside the alertView didDismissWithButtonIndex: method), everything works fine. Any idea what's happening here? Thanks in advance!

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• Best XML format for log events in terms of tool support for data mining and visualization?

  - by Thorbjørn Ravn Andersen

  We want to be able to create log files from our Java application which is suited for later processing by tools to help investigate bugs and gather performance statistics. Currently we use the traditional "log stuff which may or may not be flattened into text form and appended to a log file", but this works the best for small amounts of information read by a human. After careful consideration the best bet has been to store the log events as XML snippets in text files (which is then treated like any other log file), and then download them to the machine with the appropriate tool for post processing. I'd like to use as widely supported an XML format as possible, and right now I am in the "research-then-make-decision" phase. I'd appreciate any help both in terms of XML format and tools and I'd be happy to write glue code to get what I need. What I've found so far: log4j XML format: Supported by chainsaw and Vigilog. Lilith XML format: Supported by Lilith Uninvestigated tools: Microsoft Log Parser: Apparently supports XML. OS X log viewer: plus there is a lot of tools on http://www.loganalysis.org/sections/parsing/generic-log-parsers/ Any suggestions?

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• Recommendations for a 3rd party Calendar picker class that's easy to use in iPhone/iPad apps

  - by BeachRunnerJoe

  Hello. I'd like to add a Calendar picker control to my iPad app that is similar in appearence and functionality to the Calendar picker control in the upper right corner of the native Calendar app on the iPad. I've looked into a couple of the 3rd party frameworks that have Calendar controls like this (such as the Tapku Library), but because I'm new to iPhone OS development, I'm having a hard time figuring out how to use them, mostly because the ones I've looked at have little or no documentation. For those that have used 3rd party Calendar picker controls, can you recommend one that is... Easy to use or provide decent enough documentation to figure out how to use it Legit for use in iPhone OS 3.2+ (including 4.0) Or if you could recommend one and provide some code snippets from your projects that show how to... Initialize and display it Retrieve the date selected by the user I would most greatly appreciate it and I'm sure there are many others that would as well (and would be happy to vote up your response)! Thank you very much in advance, I'm going to continue researching this question right now!

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• Technology Plan - Which tools should I use?

  - by Armadillo

  Hi, Soon, I'll start my own software company. My primary product/solution will be a Billing/Invoice Software. In a near future, I pretend to expand this first module to an ERP. My app should be able to run as a stand-alone application and as a Web-based application (so there will be, probably two GUI for the same Database). My problem, now, is to choose the right tools; I'm talking about what programming language(s) should I use, what kind of database should I choose, and stuff like that. I'm primarily a VB6 programmer, so probably I'll choose the .net framework (vb/c#). But I'm seriously thinking about Java. Java has 2 "pros" that I really like: write once, run anywhere and it is free (I think...). I've been thinking about RIAs too, but I just don't have any substantial feedback about them... Then, I'll need a report tool. Crystal Reports? HTML based Reports? Other? Databases: I'm not sure if I should use SQL-Server Express or PostgreSQL (or other). I'd be happy to hear any comments and advices Thanks

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• Customers angry, fighting unknown DLL dependencies

  - by wheaties

  I'm a one man show developing a C++ Windows application for a customer. Over the past several months we've been running to the same problems with missing DLL dependencies on customer machines. Despite my best efforts something keeps going wrong and we get angry emails back. My boss and my boss's boss are angry with me and the customers aren't happy. I'm hoping you guys can help out and give suggestions/ideas on how to get the deliverables in order. Before some of the obvious: I have no test machine. That is, I can't replicate the customer environment nor attempt to install the app on a "clean" system to catch gotchas before shipping. I've tried using depends.exe to track down what versions of the DLLs my project is dependent upon. I'm shipping our code with the redistributables I've been able to find that way. After that it's an angry customer email waiting game. I'm required to use a third-party DLL which can not be registered (it's buggy as hell.) I'm not supposed to use Install Shield, any other automated installer, or write an install script. I provide written instructions on how to get the app installed (unzip, double click exe file.) I'm tired of taking heat for this stuff. What am I missing that I could be doing? What should I ask in terms of support from my employer? How should I ask for that support in a way that they'll provide it?

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• Tools to document/visualize call graph?

  - by Dave Griffiths

  Hi, having recently joined a project with a vast amount of code to get to grips with, I would like to start documenting and visualizing some of the flows through the call graph to give me a better understanding of how everything fits together. This is what I would like to see in my ideal tool: every node is a function/method nodes are connected if one function can call another optional square box in between detailing conditions under which call is made (or a label icon you can hover over like a tooltip) also icon on edge describing parameters hover over node and description is displayed optional icons for node to display pseudo code scenario/domain view - display subset of complete diagram for particular use-case slide view mode - for each frame, the currently executing function is highlighted plenty of options over what to display to reduce on-screen clutter the interactive use of such a tool is key, I'm not looking for a Graphviz type solution because there would be too much clutter. The ability to form a view of a subset of the entire graph would be very handy (maybe with the unimportant clutter greyed out). Don't need automatic generation from source code, happy to enter it manually. Almost like a mind-map. Does that make sense? If you are not aware of such a tool, do you also think it would be useful? (Just in case I decide to go and scratch that itch one day!)

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• Angular ng-style not changing with property

  - by ganaraj

  For the life of me I cant seem to figure out why the style property is not getting updated. In my larger application it seems to work fine. http://jsfiddle.net/ganarajpr/C2hRa/4/ Here is a fiddle which shows the issue I am currently facing. You will notice that the width and height are getting updated in the div when you change the input. But the style itself doesnt seem to be updating. Anyone can tell me what I am doing wrong here? I have tried all the following scenarios using $scope.$apply.. - Throws an error stating $apply already in progress.. $rootScope.$apply - same as above. Setting another variable in a service which is $watched in the other controller. - no change seen. It would be really cool if someone can get me an answer to this. Also would be really happy if you can tell me why exactly it is not getting updated.

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• How to model a mutually exclusive relationship in sql server

  - by littlechris

  Hi, I have to add functionality to an existing application and I've run into a data situation that I'm not sure how to model. I am being restricted to the creation of new tables and code. If I need to alter the existing structure I think my client may reject the proposal..although if its the only way to get it right this is what I will have to do. I have an Item table that can me link to any number of tables, and these tables may increase over time. The Item can only me linked to one other table, but the record in the other table may have many items linked to it. Examples of the tables/entities being linked to are "Person", "Vehicle", "Building", "Office". These are all separate tables. Example of Items are "Pen", "Stapler", "Cushion", "Tyre", "A4 Paper", "Plastic Bag", "Poster", "Decoration" For instance a "Poster" may be allocated to a "Person" or "Office" or "Building". In the future if they add a "Conference Room" table it may also be added to that. My intital thoughts are: Item { ID, Name } LinkedItem { ItemID, LinkedToTableName, LinkedToID } The LinkedToTableName field will then allow me to identify the correct table to link to in my code. I'm not overly happy with this solution, but I can't quite think of anything else. Please help! :) Thanks!

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• Fastest inline-assembly spinlock

  - by sigvardsen

  I'm writing a multithreaded application in c++, where performance is critical. I need to use a lot of locking while copying small structures between threads, for this I have chosen to use spinlocks. I have done some research and speed testing on this and I found that most implementations are roughly equally fast: Microsofts CRITICAL_SECTION, with SpinCount set to 1000, scores about 140 time units Implementing this algorithm with Microsofts InterlockedCompareExchange scores about 95 time units Ive also tried to use some inline assembly with __asm {} using something like this code and it scores about 70 time units, but I am not sure that a proper memory barrier has been created. Edit: The times given here are the time it takes for 2 threads to lock and unlock the spinlock 1,000,000 times. I know this isn't a lot of difference but as a spinlock is a heavily used object, one would think that programmers would have agreed on the fastest possible way to make a spinlock. Googling it leads to many different approaches however. I would think this aforementioned method would be the fastest if implemented using inline assembly and using the instruction CMPXCHG8B instead of comparing 32bit registers. Furthermore memory barriers must be taken into account, this could be done by LOCK CMPXHG8B (I think?), which guarantees "exclusive rights" to the shared memory between cores. At last [some suggests] that for busy waits should be accompanied by NOP:REP that would enable Hyper-threading processors to switch to another thread, but I am not sure whether this is true or not? From my performance-test of different spinlocks, it is seen that there is not much difference, but for purely academic purpose I would like to know which one is fastest. However as I have extremely limited experience in the assembly-language and with memory barriers, I would be happy if someone could write the assembly code for the last example I provided with LOCK CMPXCHG8B and proper memory barriers in the following template: __asm { spin_lock: ;locking code. spin_unlock: ;unlocking code. }

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• How to ensure DB security for a Windows Forms application?

  - by Vilx-

  The basic setup is classic - you're creating a Windows Forms application that connects to a DB and does all kinds of enterprise-y stuff. Naturally, such an application will have many users with different access rights in the DB, and each with their own login name and password. So how do you implement this? One way is to create a DB login for every application user, but that's a pretty serious thing to do, which even requires admin rights on the DB server, etc. If the DB server hosts several applications, the admins are quite likely not to be happy with this. In the web world typically one creates his own "Users" table which contains all the necessary info, and uses one fixed DB login for all interaction. That is all nice for a web app, but a windows forms can't hide this master login information, negating security altogether. (It can try to hide, but all such attempts are easily broken with a bit of effort). So... is there some middle way? Perhaps logging in with a fixed login, and then elevating priviledges from a special stored procedure which checks the username and password?

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• Encrypt a file base upon a pregenerated "key" C#

  - by Anubis

  Hello everyone. I'm trying to determine the best course of action to implement a simple "licensing" system with a partner of mine. The concept is: Generate an encrypted value based upon several internal hardware components. Have the customer send this value to us which we will implement into our key generator. Once we have that, we add any other restrictions on the license (user, expires, etc.). From there we generate a file which we send to the customer they can add to their installation and voila, happy people about. I have the first part all done. My next part is trying to figure out which encryption methodology I would need to use. I already know Symmetric Encryption is pretty much the only route I can take. Most of the information I have found involves .NET already creating a key from its own internal methods. That's a bit of background, my question is: "Which encryption method could I use which would allow me to encrypt the restrictions based upon the "id" I was given from the customer's computer?" I'm writing this in C# by the way. Any ideas would be greatly appreciated! Take Care!

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