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  • How to handle image/gif type response on client side using GWT

    - by user200340
    Hi all, I have a question about how to handle image/gif type response on client side, any suggestion will be great. There is a service which responds for retrieving image (only one each time at the moment) from database. The code is something like, JDBC Connection Construct MYSQL query. Execute query If has ResultSet, retrieve first one { //save image into Blob image, “img” is the only entity in the image table. image = rs.getBlob("img"); } response.setContentType("image/gif"); //set response type InputStream in = image.getBinaryStream(); //output Blob image to InputStream int bufferSize = 1024; //buffer size byte[] buffer = new byte[bufferSize]; //initial buffer int length =0; //read length data from inputstream and store into buffer while ((length = in.read(buffer)) != -1) { out.write(buffer, 0, length); //write into ServletOutputStream } in.close(); out.flush(); //write out The code on client side .... imgform.setAction(GWT.getModuleBaseURL() + "serviceexample/ImgRetrieve"); .... ClickListener { OnClick, then imgform.submit(); } formHandler { onSubmit, form validation onSubmitComplete ??????? //handle response, and display image **Here is my question, i had tried Image img = new Image(GWT.getHostPageBaseURL() +"serviceexample/ImgRetrieve"); mg.setSize("300", "300"); imgpanel.add(img); but i only got a non-displayed image with 300X300 size.** } So, how should i handle the responde in this case? Thanks,

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  • How to: generate UnhandledException?

    - by serhio
    I use this code to catch the WinForm application UnhandledException. [STAThread] static void Main(string[] args) { // Add the event handler for handling UI thread exceptions to the event. Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException); // Set the unhandled exception mode to force all Windows Forms errors // to go through our handler. Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException); // Add the event handler for handling non-UI thread exceptions to the event. AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException); try { Application.Run(new MainForm()); } catch.... There I will try to restart the application. Now my problem is to simulate a exception like this. I tried before try (in main): throw new NullReferenceException("test"); VS caught it. Tried also in MainForm code with button : private void button1_Click(object sender, EventArgs ev) { ThreadPool.QueueUserWorkItem(new WaitCallback(TestMe), null); } protected void TestMe(object state) { string s = state.ToString(); } did not help, VS caught it, even in Release mode. How should I, finally, force the application generate UnhandleldException? Will I be able to restart the application in CurrentDomain_UnhandledException?

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  • [F#] Parallelize code in nested loops

    - by Juliet
    You always hear that functional code is inherently easier to parallelize than non-functional code, so I decided to write a function which does the following: Given a input of strings, total up the number of unique characters for each string. So, given the input [ "aaaaa"; "bbb"; "ccccccc"; "abbbc" ], our method will returns a: 6; b: 6; c: 8. Here's what I've written: (* seq<#seq<char>> -> Map<char,int> *) let wordFrequency input = input |> Seq.fold (fun acc text -> (* This inner loop can be processed on its own thread *) text |> Seq.choose (fun char -> if Char.IsLetter char then Some(char) else None) |> Seq.fold (fun (acc : Map<_,_>) item -> match acc.TryFind(item) with | Some(count) -> acc.Add(item, count + 1) | None -> acc.Add(item, 1)) acc ) Map.empty This code is ideally parallelizable, because each string in input can be processed on its own thread. Its not as straightforward as it looks since the innerloop adds items to a Map shared between all of the inputs. I'd like the inner loop factored out into its own thread, and I don't want to use any mutable state. How would I re-write this function using an Async workflow?

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  • C++ iterators, default initialization and what to use as an uninitialized sentinel.

    - by Hassan Syed
    The Context I have a custom template container class put together from a map and vector. The map resolves a string to an ordinal, and the vector resolves an ordinal (only an initial string to ordinal lookup is done, future references are to the vector) to the entry. The entries are modified intrusively to contain a a bool "assigned" and an iterator_type which is a const_iterator to the container class's map. My container class will use RCF's serialization code (which models boost::serialization) to serialize my container classes to nodes in a network. Serializing iterator's is not possible, or a can of worms, and I can easily regenerate them onces the vectors and maps are serialized on the remote site. The Question I need to default initialize, and be able to test that the iterator has not been assigned to (if it is assigned it is valid, if not it is invalid). Since map iterators are not invalidated upon operations performed on it (unless of course items are removed :D) am I to assume that map<x,y>::end() is a valid sentinel (regardless of the state of the map -- i.e., it could be empty) to initialize to ? I will always have access to the parent map, I'm just unsure wheather end() is the same as the map contents change. I don't want to use another level of indirection (--i.e., boost::optional) to achieve my goal, I'd rather forego compiler checks to correct logic, but it would be nice if I didn't need to. Misc This question exists, but most of its content seems non-sense. Assigning a NULL to an iterator is invalid according to g++ and clang++. This is another similar question, but it focuses on the common use-cases of iterators, which generally tends to be using the iterator to iterate, ofcourse in this use-case the state of the container isn't meant to change whilst iteration is going on.

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  • Get location of element you just pushed into vector C++

    - by Satchmo Brown
    I am curious about how pushing back into a vector works. I want a way to push back an element and then be able to add it's location in the vector to a double array serving as a type of map. Something like this: // Create a bomb Bomb b; b.currentTime = SDL_GetTicks(); b.explodeTime = SDL_GetTicks() + 3000; b.owner = player; b.power = 2; b.x = x; b.y = y; bombVec.push_back(b); bombs[y][x] = THIS_IS_WHAT_I_WANT; This way when I explode the bomb, I can check the map and then have an ID in the vector to deal with. Every non bomb square will have a -1. Also, just curious. Imagine I have 3 elements in a vector. I delete the second one and then add another. Does the new element go in the same location as the one that was deleted? Thanks!

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  • How to avoid using the same identifier for Class Names and Property Names?

    - by Wololo
    Here are a few example of classes and properties sharing the same identifier: public Coordinates Coordinates { get; set; } public Country Country { get; set; } public Article Article { get; set; } public Color Color { get; set; } public Address Address { get; set; } This problem occurs more frequently when using POCO with the Entity Framework as the Entity Framework uses the Property Name for the Relationships. So what to do? Use non-standard class names? public ClsCoordinates Coordinates { get; set; } public ClsCountry Country { get; set; } public ClsArticle Article { get; set; } public ClsColor Color { get; set; } public ClsAddress Address { get; set; } public ClsCategory Category { get; set; } Yuk Or use more descriptive Property Names? public Coordinates GeographicCoordinates { get; set; } public Country GeographicCountry { get; set; } public Article WebArticle { get; set; } public Color BackgroundColor { get; set; } public Address HomeAddress { get; set; } public Category ProductCategory { get; set; } Less than ideal, but can live with it I suppose. Or JUST LIVE WITH IT? What are you best practices?

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  • optimize 2D array in C++

    - by Hristo
    I'm dealing with a 2D array with the following characteristics: const int cols = 500; const int rows = 100; int arr[rows][cols]; I access array arr in the following manner to do some work: for(int k = 0; k < T; ++k) { // for each trainee myscore[k] = 0; for(int i = 0; i < N; ++i) { // for each sample for(int j = 0; j < E[i]; ++j) { // for each expert myscore[k] += delta(i, anotherArray[k][i], arr[j][i]); } } } So I am worried about the array 'arr' and not the other one. I need to make this more cache-friendly and also boost the speed. I was thinking perhaps transposing the array but I wasn't sure how to do that. My implementation turns out to only work for square matrices. How would I make it work for non-square matrices? Also, would mapping the 2D array into a 1D array boost the performance? If so, how would I do that? Finally, any other advice on how else I can optimize this... I've run out of ideas, but I know that arr[j][i] is the place where I need to make changes because I'm accessing columns by columns instead of rows by rows so that is not cache friendly at all. Thanks, Hristo

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  • How to close all tabs in Safari using AppleScript?

    - by Form
    I have made a very simple AppleScript to close all tabs in Safari. The problem is, it works, but not completely. Here's the code: tell application "Safari" repeat with aWindow in windows repeat with aTab in tabs of aWindow aTab close end repeat end repeat end tell I've also tried this script: tell application "Safari" repeat with i from 0 to the number of items in windows set aWindow to item i of windows repeat with j from 0 to the number of tabs in aWindow set aTab to item j of tabs of aWindow aTab close end repeat end repeat end tell ... but it does not work either. I tried that on my system (MacBook Pro jan 2008), as well as on a Mac Pro G5 under Tiger and the script fails on both, albeit with a much less descriptive error on Tiger. The problem is that only a couple of tabs are closed. Running the script a few times closes a few tab each time until none is left, but always fails with the same error after closing a few tabs. Under Leopard I get an out of bounds error. Since I am using fast enumeration (not using "repeat from 0 to number of items in windows") I don't see how I can get an out of bounds error with this... My goal is to use the Cocoa Scripting Bridge to close tabs in Safari from my Objective-C Cocoa application but the Scripting Bridge fails in the same manner. The non-deletable tabs show as NULL in the Xcode debugger, while the other tabs are valid objects from which I can get values back (such as their title). In fact I tried with the Scripting Bridge first then told myself why not try this directly in AppleScript and I was surprised to see the same results. I must have a glaring omission or something in there... (seems like a bug in Safari AppleScript support to me... :S) I've used repeat loops and Obj-C 2.0 fast enumeration to iterate through collections before with zero problems, so I really don't see what's wrong here. Anyone can help? Thanks in advance!

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  • Do I need to implement an XMPP server?

    - by WTFITS
    (newbie alert) I need to program a multiparty communication service for a course project, and I am considering XMPP for it. The service needs following messaging semantics: 1) server will provide a method of registering and unregistering an address such as [email protected]/SomeResource. (for now I will do it manually). 2) server will provide a method of forwarding incoming messages from, say, [email protected]/SomeResource to [email protected]/someOtherResource, assuming that the latter is registered, and a method for removing this forwarding. (for now I will do it manually). 3) anonymous clients can send messages to, say, [email protected]/someresource (one way traffic only). If there is any forwarding setup, the message will be forwarded. Finally if the address is [email protected]/someresource is registered, the message will be stored for later delivery (or immediate if a retrieving client is online - see below). If no forwarding and unregistered, message will be silently dropped. 4) clients can connect and retrieve messages from a registered address. Exact method of authenticating clients (e.g., passwords?) is yet to be determined. Eventually, I want to add support for clients to connect from a web browser so they can register/unregister and set/remove forwarding themselves. Thus, the server will have to do some non-standard switching. Will I need to implement an XMPP server for this? I guess some (or all?) of this can also be done using a XMPP client bot

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  • HTTP Negotiate windows vs. Unix server implementation using python-kerberos

    - by ondra
    I tried to implement a simple single-sign-on in my python web server. I have used the python-kerberos package which works nicely. I have tested it from my Linux box (authenticating against active directory) and it was without problem. However, when I tried to authenticate using Firefox from Windows machine (no special setup, just having the user logged into the domain + added my server into negotiate-auth.trusted-uris), it doesn't work. I have looked at what is sent and it doesn't even resemble the things the Linux machine sends. This Microsoft description of the process pretty much resembles the way my interaction from Linux works, but the Windows machine generally sends a very short string, which doesn't even resemble the things microsoft documentation states, and when base64 decoded, it is something like 12 zero bytes followed by 3 or 4 non-zero bytes (GSS functions then return that it doesn't support such scheme) Either there is something wrong with the client Firefox settings, or there is some protocol which I am supposed to follow for the Negotiate protocol, but which I cannot find any reference anywhere. Any ideas what's wrong? Do you have any idea what protocol I should by trying to find, as it doesn' look like SPNEGO, at least from MS documentation.

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  • What database systems should an startup company consider?

    - by Am
    Right now I'm developing the prototype of a web application that aggregates large number of text entries from a large number of users. This data must be frequently displayed back and often updated. At the moment I store the content inside a MySQL database and use NHibernate ORM layer to interact with the DB. I've got a table defined for users, roles, submissions, tags, notifications and etc. I like this solution because it works well and my code looks nice and sane, but I'm also worried about how MySQL will perform once the size of our database reaches a significant number. I feel that it may struggle performing join operations fast enough. This has made me think about non-relational database system such as MongoDB, CouchDB, Cassandra or Hadoop. Unfortunately I have no experience with either. I've read some good reviews on MongoDB and it looks interesting. I'm happy to spend the time and learn if one turns out to be the way to go. I'd much appreciate any one offering points or issues to consider when going with none relational dbms?

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  • How can I perform this query between related tables without using UNION?

    - by jeremy
    Suppose I have two separate tables that I watch to query. Both of these tables has a relation with a third table. How can I query both tables with a single, non UNION based query? I want the result of the search to rank the results by comparing a field on each table. Here's a theoretical example. I have a User table. That User can have both CDs and books. I want to find all of that user's books and CDs with a single query matching a string ("awesome" in this example). A UNION based query might look like this: SELECT "book" AS model, name, ranking FROM book WHERE name LIKE 'Awesome%' UNION SELECT "cd" AS model, name, ranking FROM cd WHERE name LIKE 'Awesome%' ORDER BY ranking DESC How can I perform a query like this without the UNION? If I do a simple left join from User to Books and CDs, we end up with a total number of results equal to the number of matching cds timse the number of matching books. Is there a GROUP BY or some other way of writing the query to fix this?

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  • Bookmarkable URLs after Ajax for Wicket

    - by Wolfgang
    There is this well-known problem that browsers don't put Ajax request in the request history and cause problems for bookmarkability, forward/back button, and refresh. Also, there is a common solution to that problem that appends the hash symbol # and some additional parameters to the URL by using Javascript window.location.hash = .... In this question a basic solution to this problem is proposed, for example. = My question is if such a solution has been integrated in Wicket, so that existing Wicket facilities are used and no custom Javascript had to be added. If not, I'd be interested in how this could be done. Such a solution had to answer the question what should be put after the hash. I like the idea that the bookmarkable URL that (in the non-Ajax case) were in front of the hash could be put behind it. For example, when you are on http://host/catalog and reach a page http://host/product/xyz the Ajax-triggered URL would be http://host/catalog#/product/xyz. Then it would be easy to write an onload handler that checks for the # and does a redirect to the URL after the hash.

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  • 60K+ Sprites on the 360?

    - by Jeffrey Kern
    Hey everyone, Just wondering - throwing ideas in my head - about starting a new XNA project for the 360. I would like it to be retro-old school, and emulating scanlines and color palettes and such. As part of this idea, what I would ideally like to do is manually draw each and every pixel of the screen. So, worst-case scenario I would have to draw about 60K sprites on a 252x240 resolution (I think thats correct). 60K sprites on the screen at a time. So, before I even attempt to code this - would the XBOX 360 be able to keep up with this even? That is a lot of sprites, but they aren't big sprites, and the texture data needed would be non-existant. However, I guess how this project would be implemented would make it or break it, but all I was thinking was coming up with a 2D array and mapping which color value would need to be drawn at that point. Of course, this is watered down talk right now. But what you all suggest? EDIT: Each sprite would represent one pixel. E.g., a sprite at 0,0. Another at 0,1. etc.

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  • Regex to check if exact string exists

    - by Jayrox
    I am looking for a way to check if an exact string match exists in another string using Regex or any better method suggested. I understand that you tell regex to match a space or any other non-word character at the beginning or end of a string. However, I don't know exactly how to set it up. Search String: t String 1: Hello World, Nice to see you! t String 2: Hello World, Nice to see you! String 3: T Hello World, Nice to see you! I would like to use the search string and compare it to String 1, String 2 and String 3 and only get a positive match from String 1 and String 3 but not from String 2. Requirements: Search String may be at any character position in the Subject. There may or may not be a white-space character before or after it. I do not want it to match if it is part of another string; such as part of a word. For the sake of this question: I think I would do this using this pattern: /\bt\b/gi /\b{$search_string}\b/gi Does this look right? Can it be made better? Any situations where this pattern wouldn't work? Additional info: this will be used in PHP 5

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  • OSMF seek with Amazon Cloudfront

    - by giorrrgio
    I've written a little OSMF player that streams via RTMP from Amazon Cloudfront. There's a known issue, the mp3 duration is not correctly readed from metadata and thus the seek function is not working. I know there's a workaround implying the use of getStreamLength function of NetConnection, which I successfully implemented in a previous non-OSMF player, but now I don't know how and when to call it, in terms of OSMF Events and Traits. This code is not working: protected function initApp():void { //the pointer to the media var resource:URLResource = new URLResource( STREAMING_PATH ); // Create a mediafactory instance mediaFactory = new DefaultMediaFactory(); //creates and sets the MediaElement (generic) with a resource and path element = mediaFactory.createMediaElement( resource ); var loadTrait:NetStreamLoadTrait = element.getTrait(MediaTraitType.LOAD) as NetStreamLoadTrait; loadTrait.addEventListener(LoaderEvent.LOAD_STATE_CHANGE, _onLoaded); player = new MediaPlayer( element ); //Marker 5: Add MediaPlayer listeners for media size and current time change player.addEventListener( DisplayObjectEvent.MEDIA_SIZE_CHANGE, _onSizeChange ); player.addEventListener( TimeEvent.CURRENT_TIME_CHANGE, _onProgress ); initControlBar(); } private function onGetStreamLength(result:Object):void { Alert.show("The stream length is " + result + " seconds"); duration = Number(result); } private function _onLoaded(e:LoaderEvent):void { if (e.newState == LoadState.READY) { var loadTrait:NetStreamLoadTrait = player.media.getTrait(MediaTraitType.LOAD) as NetStreamLoadTrait; if (loadTrait && loadTrait.netStream) { var responder:Responder = new Responder(onGetStreamLength); loadTrait.connection.call("getStreamLength", responder, STREAMING_PATH); } } }

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  • What is the best approach to 2D collision detection on the iPhone?

    - by Magic Bullet Dave
    Been working on this problem of collision detection and there appears to be 3 main approaches I could take: Sprite and mask approach. (AND the overlap of the sprites and check for a non-zero number in the resulting sprite pixel data). Bounding circles, rectangles or polygons. (Create one or more shapes that enclose the sprites and do the basic maths to check for overlaps). Use an existing sprite library. The first approach, even though it would have been the way I would have done it in the old days of 16x16 sprite blocks, it appears that there just isn’t an easy way of getting at the individual image pixel data and/or alpha channel within Quartz (or OPENGL for that matter). Detecting the overlap of the bounding box is easy, but then creating a 3rd image from the overlap and then testing it for pixels is complicated and my gut feel is that even if we could get it to work would be slow. Am I missing something neat here? The second approach involves dividing up our sprites into several polygons and testing them for overlaps. The more polygons the more accurate the collision detection. The benefit is that it is fast, and can be accurate. The downside is it makes the sprite creation more complicated. i.e., we have to create the polygons for each sprite. For speed the best approach is to create a tree of polygons. The 3rd approach I’m not sure about as it involves buying code (or using an open source licence). I am not sure what the best library to use is or whether this would make life easier or give us a problem integrating this into our app. So in short I am favouring the polygon and tree approach and would appreciate you views on this before I go and write lots of code. Best regards Dave

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  • Stored Procedures In Source Control - Automate Build/Deployment Process

    - by Alex
    My company provides a large .NET service-oriented solution. The services layer interact with a T-SQL back-end consisting of hundreds of tables and stored procedures. Our C# code is in version-control (SVN) but our stored procedures and schema are not. After much lobbying of expedient upper-management, I was allowed to review our (non-existent) build/deployment process to accomplish the following goals: Place schema and stored procedures under source-control. Automate the build/deployment process. I would like to proceed per the accepted answer's strategy in this post but have additional questions: I would like to use Hudson as my build server. Is this a reasonable choice for a C#/SQL solution? What better alternatives should I explore? Assuming I have all triggers, stored-procedures, schema, etc... under source control, and that they are scripted to individual files, how do I generate a build script which will take into account dependencies/references between these items? (SQL Server does this automatically, but it generates one giant script) What does the workflow of performing an update at the client look like? i.e. I have to keep existing table data. How do I roll-back schema changes? I am the only programmer. Several other pseudo-technical staff like to make changes directly inside SQL Management Studio. Is it realistic to expect others to adhere to this solution -- how can I enforce this? Thank you in advance for your help.

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  • Can not access response.body inside after filter block in Sinatra 1.0

    - by Petr Vostrel
    I'm struggling with a strange issue. According to http://github.com/sinatra/sinatra (secion Filters) a response object is available in after filter blocks in Sinatra 1.0. However the response.status is correctly accessible, I can not see non-empty response.body from my routes inside after filter. I have this rackup file: config.ru require 'app' run TestApp Then Sinatra 1.0.b gem installed using: gem install --pre sinatra And this is my tiny app with a single route: app.rb require 'rubygems' require 'sinatra/base' class TestApp < Sinatra::Base set :root, File.dirname(__FILE__) get '/test' do 'Some response' end after do halt 500 if response.empty? # used 500 just for illustation end end And now, I would like to access the response inside the after filter. When I run this app and access /test URL, I got a 500 response as if the response is empty, but the response clearly is 'Some response'. Along with my request to /test, a separate request to /favicon.ico is issued by the browser and that returns 404 as there is no route nor a static file. But I would expect the 500 status to be returned as the response should be empty. In console, I can see that within the after filter, the response to /favicon.ico is something like 'Not found' and response to /test really is empty even though there is response returned by the route. What do I miss?

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  • pdf external streams in Max OS X Preview

    - by olpa
    According to the specification, a part of a PDF document can reside in an external file. An example for an image: 2 0 obj << /Type /XObject /Subtype /Image /Width 117 /Height 117 /BitsPerComponent 8 /Length 0 /ColorSpace /DeviceRGB /FFilter /DCTDecode /F (pinguine.jpg) >> stream endstream endobj I found that this functionality does work in Adobe Acrobat 5.0 for Windows (sample PDF with the image), also I managed to view this file in Adobe Acrobat Reader 8.1.3 for Mac OS X after I found the setting "Allow external content". Unfortunately, it seems that non-Adobe tools ignore the external stream feature. I hope I'm wrong, therefore ask the question: How to enable external streams in Mac OS X? (I think that all the system Mac OS X tools use the same library, therefore say "Mac OS X" instead of "Preview".) Or maybe there could be a programming hook to emulate external streams? My task is: store a big set of images (total ˜300Mb) outside of a small PDF (˜1Mb). At some moment, I want to filter PDF through a quartz filter and get a PDF with the images embedded. Any suggestions are welcome.

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  • Should I use a regular server instead of AWS?

    - by Jon Ramvi
    Reading about and using the Amazon Web Services, I'm not really able to grasp how to use it correctly. Sorry about the long question: I have a EC2 instance which mostly does the work of a web server (apache for file sharing and Tomcat with Play Framework for the web app). As it's a web server, the instance is running 24/7. It just came to my attention that the data on the EC2 instance is non persistent. This means I lose my database and files if it's stopped. But I guess it also means my server settings and installed applications are lost as they are just files in the same way as the other data. This means that I will either have to rewrite the whole app to use amazon CloudDB or write some code which stores the db on S3 and make my own AMI with the correct applications installed and configured. Or can this be quick-fixed by using EBS somehow? My question is 1. is my understanding of aws is correct? and 2. is it's worth it? It could be a possibility to just set up a regular dedicated server where everything is persistent, as you would expect. Would love to have the scaleability of aws though..

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  • Determining polygon intersection and containment

    - by Victor Liu
    I have a set of simple (no holes, no self-intersections) polygons, and I need to check that they don't intersect each other (one can be entirely contained in another; that is okay). I can check this by simply checking the per-vertex inside-ness of one polygon versus other polygons. I also need to determine the containment tree, which is the set of relationships that say which polygon contains any given polygon. Since no polygon can intersect any other, then any contained polygon has a unique container; the "next-bigger" one. In other words, if A contains B contains C, then A is the parent of B, and B is the parent of C, and we don't consider A the parent of C. The question: How do I efficiently determine the containment relationships and check the non-intersection criterion? I ask this as one question because maybe a combined algorithm is more efficient than solving each problem separately. The algorithm should take as input a list of polygons, given by a list of their vertices. It should produce a boolean B indicating if none of the polygons intersect any other polygon, and also if B = true, a list of pairs (P, C) where polygon P is the parent of child C. This is not homework. This is for a hobby project I am working on.

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  • Immutable classes in C++

    - by ereOn
    Hi, In one of my projects, I have some classes that represent entities that cannot change once created, aka. immutable classes. Example : A class RSAKey that represent a RSA key which only has const methods. There is no point changing the existing instance: if you need another one, you just create one. My objects sometimes are heavy and I enforced the use of smart pointers to avoid copy. So far, I have the following pattern for my classes: class RSAKey : public boost::noncopyable, public boost::enable_shared_from_this<RSAKey> { public: /** * \brief Some factory. * \param member A member value. * \return An instance. */ static boost::shared_ptr<const RSAKey> createFromMember(int member); /** * \brief Get a member. * \return The member. */ int getMember() const; private: /** * \brief Constructor. * \param member A member. */ RSAKey(int member); /** * \brief Member. */ const int m_member; }; So you can only get a pointer (well, a smart pointer) to a const RSAKey. To me, it makes sense, because having a non-const reference to the instance is useless (it only has const methods). Do you guys see any issue regarding this pattern ? Are immutable classes something common in C++ or did I just created a monster ? Thank you for your advices !

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  • Are there more secure alternatives to the .Net SQLConnection class?

    - by KeyboardMonkey
    Hi SO people, I'm very surprised this issue hasn't been discussed in-depth: This article tells us how to use windbg to dump a running .Net process strings in memory. I spent much time researching the SecureString class, which uses unmanaged pinned memory blocks, and keeps the data encrypted too. Great stuff. The problem comes in when you use it's value, and assign it to the SQLConnection.ConnectionString property, which is of the System.String type. What does this mean? Well... It's stored in plain text Garbage Collection moves it around, leaving copies in memory It can be read with windbg memory dumps That totally negates the SecureString functionality! On top of that, the SQLConnection class is non-inheritable, I can't even roll my own with a SecureString property instead; Yay for closed-source. Yay. A new DAL layer is in progress, but for a new major version and for so many users it will be at least 2 years before every user is upgraded, others might stay on the old version indefinitely, for whatever reason. Because of the frequency the connection is used, marshalling from a SecureString won't help, since the immutable old copies stick in memory until GC comes around. Integrated Windows security isn't an option, since some clients don't work on domains, and other roam and connect over the net. How can I secure the connection string, in memory, so it can't be viewed with windbg?

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  • scanf segfaults and various other anomalies inside while loop

    - by Shadow
    while(1){ //Command prompt char *command; printf("%s>",current_working_directory); scanf("%s",command);<--seg faults after input has been received. printf("\ncommand:%s\n",command); } I am getting a few different errors and they don't really seem reproducible(except for the segfault at this point .<). This code worked fine about 10 minutes ago, then it infinite looped the printf command and now it seg faults on the line mentioned above. The only thing I changed was scanf("%s",command); to what it currently is. If I change the command variable to be an array it works, obviously this is because the storage is set aside for it. 1) I got prosecuted about telling someone that they needed to malloc a pointer* (But that usually seems to solve the problem such as making it an array) 2) the command I am entering is "magic" 5 characters so there shouldn't be any crazy stack overflow. 3) I am running on mac OSX 10.6 with newest version of xCode(non-OS4) and standard gcc 4) this is how I compile the program: gcc --std=c99 -W sfs.c Just trying to figure out what is going on. Being this is for a school project I am never going to have to see again, I will just code some noob work around that would make my boss cry :) But for afterwards I would love to figure out why this is happening and not just make some fix for it, and if there is some fix for it why that fix works.

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