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  • Wrapping unmanaged C++ with C++/CLI - a proper approach.

    - by Jamie
    Hi there, as stated in the title, I want to have my old C++ library working in managed .NET. I think of two possibilities: 1) I might try to compile the library with /clr and try "It Just Works" approach. 2) I might write a managed wrapper to the unmanaged library. First of all, I want to have my library working FAST, as it was in unmanaged environment. Thus, I am not sure if the first approach will not cause a large decrease in performance. However, it seems to be faster to implement (not a right word :-)) (assuming it will work for me). On the other hand, I think of some problems that might appear while writing a wrapper (e.g. how to wrap some STL collection (vector for instance)?) I think of writing a wrapper residing in the same project as the unmanaged C++ resides - is that a reasonable approach (e.g. MyUnmanagedClass and MyManagedClass in the same project, the second wrapping the other)? What would you suggest in that problem? Which solution is going to give me better performance of the resulting code? Thank you in advance for any suggestions and clues! Cheers

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  • How does DateTime.Now affect query plan caching in SQL Server?

    - by Bill Paetzke
    Question: Does passing DateTime.Now as a parameter to a proc prevent SQL Server from caching the query plan? If so, then is the web app missing out on huge performance gains? Possible Solution: I thought DateTime.Today.AddDays(1) would be a possible solution. It would pass the same end-date to the sql proc (per day). And the user would still get the latest data. Please speak to this as well. Given Example: Let's say we have a stored procedure. It reports data back to a user on a webpage. The user can set a date range. If the user sets today's date as the "end date," which includes today's data, the web app passes DateTime.Now to the sql proc. Let's say that one user runs a report--5/1/2010 to now--over and over several times. On the webpage, the user sees 5/1/2010 to 5/4/2010. But the web app passes DateTime.Now to the sql proc as the end date. So, the end date in the proc will always be different, although the user is querying a similar date range. Assume the number of records in the table and number of users are large. So any performance gains matter. Hence the importance of the question. Example proc and execution (if that helps to understand): CREATE PROCEDURE GetFooData @StartDate datetime @EndDate datetime AS SELECT * FROM Foo WHERE LogDate >= @StartDate AND LogDate < @EndDate Here's a sample execution using DateTime.Now: EXEC GetFooData '2010-05-01', '2010-05-04 15:41:27' -- passed in DateTime.Now Here's a sample execution using DateTime.Today.AddDays(1) EXEC GetFooData '2010-05-01', '2010-05-05' -- passed in DateTime.Today.AddDays(1) The same data is returned for both procs, since the current time is: 2010-05-04 15:41:27.

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  • Problems with display of UTF-8 encoded content from a DB

    - by LookUp Webmaster
    Dear members of the Stackoverflow community, We are developing a web application using the Zend Framework, and we are facing some encoding issues that we hope you might help us solve. The situation goes something like this: There are certain tables on a MySQL database that need to be displayed as html. Because the site is designed using the Spanish language, the database contains some characters like "á" or "ñ". Our internal policy is to set all the encodings as UTF-8, including all the databases and the tables. The problem is, that when we retrieve the content from the DB, some characters are displayed as question marks. We are out of ideas. These are all the things that we have already tried and double-checked: 1. The SQL file from which we load all the data is properly UTF-8 encoded. 2. The SQL is loaded through phpmyadmin (which is configured as UTF-8), and the resulting tables are displayed properly. 3. The netbeans environment used for coding is also set as UTF-8. The weird thing is that all the content that is hard-coded either as php or html is displayed properly. Only the values that are extracted from the database have issues. Any ideas? Thank you very much.

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  • [jscript] Good (better) substition for setInterval or setTimeout

    - by riffnl
    I've got a masterpage with some nice UI (jQuery) features. One of these options is interefering with my embedded YouTube (or other alike-) objects. On each, in this case, setInterval event the embedded video stops displaying new frames (for like a second). More detail: I've got a "polaroid" gallery (in the header) with only 5 100x100 images in it (test: preloading has no effect on performance) and my gallery will show or hide them (fade-in / fade-out) after a period of time. (test: non-animated display:hide or display:block has no effect on performance). After some testing and I've come to the conclusion that it isn't the "animated" showing or hiding of the pictures, but it's the interval itself (- since altering to display:hide or block had the same result). Perhaps it is my "gallery" "function" on itself ... function poladroid() { if (!galleryHasFocus) { if (galleryMax >= 0) { galleryCurrent++; if (galleryCurrent > galleryMax) { galleryCurrent = 0; showPictures = !showPictures; } if (showPictures) { $('#pic-' + galleryCurrent.toString()).show("slow"); } else { $('#pic-' + galleryCurrent.toString()).hide("slow"); } } } if (!intervalSet) { window.setInterval("poladroid()", 3000); intervalSet = true; } } It's not like my function is doing really awkward stuff is it? So, I was thinking I needed a more "loose" interval function.. but is there an option for it?

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  • Windows 7 versus Windows XP multithreading - Delphi app not acting right

    - by Robert Oschler
    I'm having a problem with a Delphi Pro 6 application that I wrote on my Windows XP machine when it runs on Windows 7. I don't have Windows 7 to test yet and I'm trying to see if Windows 7 might be the source of the trouble. Is there a fundamental difference between the way Windows 7 handles threads compared to Windows XP? I am seeing things happen out of sequence in my error logs on Windows 7 and it's causing problems. For example, objects that should have been initialized are uninitialized when running on Windows 7, yet those objects are initialized on Windows XP by the time they are needed. Some questions: 1) Are there any core differences that could cause threads/processes to behave differently between the two operating system versions? 2) I know this next question may seem absurd, but does Windows 7 attempt to split/fork threads that aren't split/forked on Windows XP? 3) And lastly, are there any known issues with FPU handling that can cause XP programs trouble when run on Windows 7 due to operational differences in wait state handling or register storage, or perhaps something like Exception mask settings, etc? 4) Any 32-bit versus 64-bit issues that could be creating trouble here? -- roschler

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  • How to read time from recorded surveillance camera video?

    - by stressed_geek
    I have a problem where I have to read the time of recording from the video recorded by a surveillance camera. The time shows up on the top-left area of the video. Below is a link to screen grab of the area which shows the time. Also, the digit color(white/black) keeps changing during the duration of the video. http://i55.tinypic.com/2j5gca8.png Please guide me in the direction to approach this problem. I am a Java programmer so would prefer an approach through Java. EDIT: Thanks unhillbilly for the comment. I had looked at the Ron Cemer OCR library and its performance is much below our requirement. Since the ocr performance is less than desired, I was planning to build a character set using the screen grabs for all the digits, and using some image/pixel comparison library to compare the frame time with the character-set which will show a probabilistic result after comparison. So I was looking for a good image comparison library(I would be OK with a non-java library which I can run using the command-line). Also any advice on the above approach would be really helpful.

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  • Is memory allocation in linux non-blocking?

    - by Mark
    I am curious to know if the allocating memory using a default new operator is a non-blocking operation. e.g. struct Node { int a,b; }; ... Node foo = new Node(); If multiple threads tried to create a new Node and if one of them was suspended by the OS in the middle of allocation, would it block other threads from making progress? The reason why I ask is because I had a concurrent data structure that created new nodes. I then modified the algorithm to recycle the nodes. The throughput performance of the two algorithms was virtually identical on a 24 core machine. However, I then created an interference program that ran on all the system cores in order to create as much OS pre-emption as possible. The throughput performance of the algorithm that created new nodes decreased by a factor of 5 relative the the algorithm that recycled nodes. I'm curious to know why this would occur. Thanks. *Edit : pointing me to the code for the c++ memory allocator for linux would be helpful as well. I tried looking before posting this question, but had trouble finding it.

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  • What is the best practice for including third party jar files in a Java program?

    - by ZoFreX
    I have a program that needs several third-party libraries, and at the moment it is packaged like so: zerobot.jar (my file) libs/pircbot.jar libs/mysql-connector-java-5.1.10-bin.jar libs/c3p0-0.9.1.2.jar As far as I know the "best" way to handle third-party libs is to put them on the classpath in the manifest of my jar file, which will work cross-platform, won't slow down launch (which bundling them might) and doesn't run into legal issues (which repackaging might). The problem is for users who supply the third party libraries themselves (example use case, upgrading them to fix a bug). Two of the libraries have the version number in the file, which adds hassle. My current solution is that my program has a bootstrapping process which makes a new classloader and instantiates the program proper using it. This custom classloader adds all .jar files in lib/ to its classpath. My current way works fine, but I now have two custom classloaders in my application and a recent change to the code has caused issues that are difficult to debug, so if there is a better way I'd like to remove this complexity. It also seems like over-engineering for what I'm sure is a very common situation. So my question is, how should I be doing this?

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  • Multi-reader IPC solution?

    - by gct
    I'm working on a framework in C++ (just for fun for now), that lets the user write plugins that use a standard API to stream data between each other. There's going to be three basic transport mechanisms for the data: files, sockets, and some kind of IPC piping system. The system is set up so that for the non-file transport, each stream can have multiple readers. IE once a server socket it setup, multiple computers can connect and stream the data. I'm a little stuck at the multi-reader IPC system though. All my plugins run in threads so they live in the same address space, so some kind of shared memory system would work fine, I was thinking I'd write my own circular buffer with a write pointer and read pointers chassing it around the buffer, but I have my doubts that I can achieve the same performance as something like linux pipes. I'm curious what people would suggest for a multi-reader solution to something like this? Is the overhead for pipes or domain sockets low enough that I could just open a connection to each reader and issue separate writes to each reader? This is intended to be significant volumes of data (tens of mega-samples/sec), so performance is a must.

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  • Why is Grails Searchable Plugin causing errors on Hibernate AutoFlush?

    - by Mark Rogers
    In the Grails 1.2.5 project that I am trying to troubleshoot, we use the Grails Searchable plugin .5.5.1. The problem is that whenever we attempt to index large sets domain classes, Grails keeps throwing: ERROR hibernate.AssertionFailure - an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session) org.hibernate.AssertionFailure: collection [domain-class] was not processed by flush() But the domain classes involved have been mapped and used by hibernate without issues outside of the calls to searchable plugin. The use of the searchable plugin goes as follows: Create a compass session with compass.openSession() Begin compass transaction: compassSession.beginTransaction() Then compassSession.create(result.get(0)) is called on an important unindexed domain class Finally compassTransaction.commit() is called to commit the transaction. Goto 2 and process next domain class Between the 3 and 4th Domain class, an autoflush is triggered that throws the error. Can anyone give me any hints about how to solve this problem? Has anyone encountered this problem before? I know that they had a systemic issue with this back in pre .5 versions of the searchable-plugin. Is it possible those issues weren't totally fixed?

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  • Best practice how to store HTML in a database column

    - by tbrandao
    I have an application that modifies a table dynamically, think spreadsheet), then upon saving the form (which the table is part of) ,I store that changed table (with user modifications) in a database column named html_Spreadhseet,along with the rest of the form data. right now I'm just storing the html in a plain text format with basic escaping of characters... I'm aware that this could be stored as a separate file, the source table (html_workseeet) already is. But from a data handling perspective its easier to save the changed html table to and from a column so as to avoid having to come up with a file management strategy (which folder will this live in, now must include folder in backups, security issues now need to apply to files, how to sync db security with file system etc.), so to minimize these issues I'm only storing the ... part in the database column. My question is should I gzip the HTML , maybe use JSON, or some other format to easily store and retrieve the HTML from the database column, what is the best practice to store HTML content in a datbase? Or just store it as I currently am as an escaped text column?

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  • Oracle Forms on-button-pressed trigger to solve three scenarios

    - by DBase486
    Hello, I'm writing a when-button-pressed trigger on a save button for an Oracle Forms 6i form, and it has to fulfill a couple of scenarios. Here's some background information: the fields we're primarily concerned with are: n_number, alert_id, end_date For all three scenarios we are comparing candidate records against the following records in the database (for the sake of argument, let's assume they're the only records in the database so far): alert_id|| n_number|| end_date ------------------------------------- 1|| 5|| _______ 2|| 6|| 10/25/2009 Scenario 1: The user enters a new record: alert_id 1 n_number 5 end_date NULL Objective: prevent the user from committing duplicate rows Scenario 2: The user enters a new record: alert_id 1 n_number 10 end_date NULL Objective: Notify the user that this alert_id already exists, but allow the user the ability to commit the row, if desired. Scenario 3: The user enters a new record: alert_id 2 n_number 6 end_date NULL Objective: Notify the user that this alert_id has occurred in the past (i.e. it has a not-null end_date), but allow the user to commit the row, if desired. I've written the code, which seems to comply with the first two scenarios, but prevents me from fulfilling the third. Issues: When I enter the third scenario case, I am prompted to commit the record, but when I attempt this, the "duplicate_stop" alert pops up, preventing me. Issues: I'm getting the following error: ORA-01843: not a valid month. While testing the code for the third scenario in Toad (hard-coding the values, etc) things seemed to be fine. Why would I encounter these problems at run-time? Help is very much appreciated. Thank you

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  • Groovy htmlunit getFirstByXPath returning null

    - by StartingGroovy
    I have had a few issues with HtmlUnit returning nulls lately and am looking for guidance. each of my results for grabbing the first row of a website have returned null. I am wondering if someone can A) explain why they might be returning null B) explain better ways (if there are some) to go about getting the information Here is my current code (URL is in the source): client = new WebClient(BrowserVersion.FIREFOX_3) client.javaScriptEnabled = false def url = "http://www.hidemyass.com/proxy-list/" page = client.getPage(url) IpAddress = page.getFirstByXPath("//html/body/div/div/form/table/tbody/tr/td[2]").getValue() println "IP Address is: $data" //returns null //Port_Number is an Image Country = page.getFirstByXPath("//html/body/div/div/form/table/tbody/tr/td[4][@class='country']/@rel").getValue() println "Country abbreviation is: $Country" //differentiate speed and connection by name of gif? Type = page.getFirstByXPath("//html/body/div/div/form/table/tbody/tr/td[7]").getValue() println "Proxy type is: $Type" Anonymity = page.getFirstByXPath("//html/body/div/div/form/table/tbody/tr/td[8]").getValue() println "Anonymity Level is: $Anonymity" client.closeAllWindows() Right now all of my XPaths return null and .getValue() obviously doesn't work on null. I also have questions as to what I should do about the PORT since it is an image? Is there a better alternative than downloading it and attempting to solve it by OCR? Side Note There is no significance in this site, I was just looking for a site that I could practice scraping on (the last one I ran into issues of fragment identities and couldn't get an answer to: HtmlUnit getByXpath returns null and HtmlUnit and Fragment Identities )

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  • Bind an Incode DataTemplate in WPF

    - by Mike Bynum
    I have a WPF Application which is using MVVM. I know that there ways of doing this in XAML but I am working on a plugin architecture and came up with a solution where a plugin exposes it's viewmodel to my plugin host's viewmodel and it's datatemplate. I want to leave the lifetime management of the plugin view up to WPF. I have tried having the plugins expose a UserControl but ran into issues when WPF decided to dispose of my UserControl so I would not reattach it without weird hacky work arounds. I am having issues getting some sort of binding working to where i can bind a control to the data and it's template to my data template. I have a ViewModel which looks something like: public class MyViewModel { public DataTemplate SelectedTemplate{ get; set;} public object SelectedViewModel {get; set;} } The selected template and viewmodel are determined somewhere else in the code but are irrelevant to my question. My question is how i can bind to a DataTemplate so that I know how to display the data shown in the SelectedViewModel. The DataTemplate is a DataTemplate created incode which respresents: <DataTemplate DataType="{x:Type vm:MyViewModel}"> <v:MyUserControl /> </DataTemplate> I have tried: <UserControl Template="{Binding Path=SelectedTemplate}" Content="{Binding Path=SelectedViewModel"} /> But UserControl expects a control template and not a data template.

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  • LNK2019 Against CArray Add, GetAt, GetSize, all includes are present

    - by David J
    I'm having some issues trying to Compile a DLL, but I just can't see where this linking error is coming from. My LNK2019 is: Exports.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: int __thiscall CArray<struct HWND__ *,struct HWND__ *>::Add(struct HWND__ *)" (__imp_?Add@? $CArray@PAUHWND__@@PAU1@@@QAEHPAUHWND__@@@Z) referenced in function "int __stdcall _Disable(struct HWND__ *,long)" (?_Disable@@YGHPAUHWND__@@J@Z) Disable(...) is... static BOOL CALLBACK _Disable(HWND hwnd, LPARAM lParam) { CArray<HWND, HWND>* pArr = (CHWndArray*)lParam; if(::IsWindowEnabled(hwnd) && ::IsWindowVisible(hwnd)) { pArr->Add(hwnd); ::Enable(hwnd, FALSE); } } This is the first function in Exports.cpp; right above it is #include <afxtempl.h> I have the Windows 7.1 SDK installed (and have tried reinstalling both that and VS2010). The exact same project compiles perfectly fine on other machines, so it can't be the code itself.. I've spent countless errors researching, which led to desperate attempts of just changing random values in the solution file, including different Windows headers, etc. My last resort is getting to be just reinstalling the OS completely (assuming it's actually a problem with the Windows SDK being incorrect or something). Any suggestions at all would be a huge help. EDIT: I've added /showIncludes on the cpp giving issues, and I do see afxtempl.h being included. It's being included multiple times due to other headers including it, but it is there (and it is from the same directory every time): 1> Note: including file: C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\atlmfc\include\afxtempl.h

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  • JAR files, don't they just bloat and slow Java down?

    - by Josamoto
    Okay, the question might seem dumb, but I'm asking it anyways. After struggling for hours to get a Spring + BlazeDS project up and running, I discovered that I was having problems with my project as a result of not including the right dependencies for Spring etc. There were .jars missing from my WEB-INF/lib folder, yes, silly me. After a while, I managed to get all the .jar files where they belong, and it comes at a whopping 12.5MB at that, and there's more than 30 of them! Which concerns me, but it probably and hopefully shouldn't be concerned. How does Java operate in terms of these JAR files, they do take up quite a bit of hard drive space, taking into account that it's compressed and compiled source code. So that can really quickly populate a lot of RAM and in an instant. My questions are: Does Java load an entire .jar file into memory when say for instance a class in that .jar is instantiated? What about stuff that's in the .jar that never gets used. Do .jars get cached somehow, for optimized application performance? When a single .jar is loaded, I understand that the thing sits in memory and is available across multiple HTTP requests (i.e. for the lifetime of the server instance running), unlike PHP where objects are created on the fly with each request, is this assumption correct? When using Spring, I'm thinking, I had to include all those fiddly .jars, wouldn't I just be better off just using native Java, with say at least and ORM solution like Hibernate? So far, Spring just took extra time configuring, extra hard drive space, extra memory, cpu consumption, so I'm concerned that the framework is going to cost too much application performance just to get for example, IoC implemented with my BlazeDS server. There still has to come ORM, a unit testing framework and bits and pieces here and there. It's just so easy to bloat up a project quickly and irresponsibly easily. Where do I draw the line?

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  • Why does my jQuery/YQL call not return anything?

    - by tastyapple
    I'm trying to access YQL with jQuery but am not getting a response: http://jsfiddle.net/tastyapple/grMb3/ Anyone know why? $(function(){ $.extend( { _prepareYQLQuery: function (query, params) { $.each( params, function (key) { var name = "#{" + key + "}"; var value = $.trim(this); if (!value.match(/^[0-9]+$/)) { value = '"' + value + '"'; } query = query.replace(name, value); } ); return query; }, yql: function (query) { var $self = this; var successCallback = null; var errorCallback = null; if (typeof arguments[1] == 'object') { query = $self._prepareYQLQuery(query, arguments[1]); successCallback = arguments[2]; errorCallback = arguments[3]; } else if (typeof arguments[1] == 'function') { successCallback = arguments[1]; errorCallback = arguments[2]; } var doAsynchronously = successCallback != null; var yqlJson = { url: "http://query.yahooapis.com/v1/public/yql", dataType: "jsonp", success: successCallback, async: doAsynchronously, data: { q: query, format: "json", env: 'store://datatables.org/alltableswithkeys', callback: "?" } } if (errorCallback) { yqlJson.error = errorCallback; } $.ajax(yqlJson); return $self.toReturn; } } ); $.yql( "SELECT * FROM github.repo WHERE id='#{username}' AND repo='#{repository}'", { username: "jquery", repository: "jquery" }, function (data) { if (data.results.repository["open-issues"].content > 0) { alert("Hey dude, you should check out your new issues!"); } } ); });

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  • How to keep windows from paging block of memory

    - by photo_tom
    We are working on a Vista/Windows 7 applicaiton that will be running in 64 bit mode using VS2008/C++. We will be needing to cache hundreds of 2-3 mb blobs of data in RAM for performance reasons up to some memory limit. Our usage profile is such that we cannot read the data in fast enough if it is all on the the disk. Cached Memory usage will be larger than 1gb memory used. For this to work well, we need to ensure that Windows does not page this memory out as it will defeat the purpose of why we are doing this. I've done a fair amount of research and cannot find documenation that states exactly how to do this. I've seen several references that infer memory mapped files work this way. Is there an expert who can clarify this for me? I'm aware there are other programs that we could adapt to do this, for example, splitting the blobs and loading into memcache or inmemory databases, but they all have too many problems with performance or code complexity. Suggestions?

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  • Can TFS workspaces be used without being tied to a specific machine?

    - by GWLlosa
    So I've got a situation where we have a project with 10 developers. Each developer, when they come in for the day, is randomly issued a machine to use for development that day. The machine names are different, say DEV01 - DEV10. At the time that they are issued to the developers, the machines are identical, and no changes the developers make during the day are persisted on the machines (source code changes are stored in TFS, not locally). These are of course actually virtual machines, but that's not really relevant to the point at hand. The problem is that each morning, the developers run into 3 issues: 1) The machine that they are assigned may not be the same machine they were last assigned to. For example, DevMan A might have used DEV04 yesterday, and received DEV06 today. His workspace definitions are now tied to DEV06; he must create a new workspace, or migrate the old workspace to DEV04. 2) The machine that they are assigned may have been in use yesterday, and some of the mappings may conflict. For example, DevMan A might have DEV04 today, and wish to create a workspace mapping the project folder to "C:\MyProj\Solution". However, DevMan B had DEV04 yesterday, and he used the same project folder. TFS now complains. 3) This may be the first time they are on a given machine. They now need to recreate for this machine all of their source-control mappings for the new machine. All of these issues can be resolved in a straightforward fashion on a case-by-case basis, but it does sap some productivity from the morning. We'd much prefer if the TFS workspace definitions could be 'relaxed', such that they did not include the machine name in the definition somehow. Barring that, if anyone is aware of a solution to the above problems that can run automatically, or with limited user intervention, that would also be ideal.

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  • Dictionaries with more than one key per value in Python

    - by nickname
    I am attempting to create a nice interface to access a data set where each value has several possible keys. For example, suppose that I have both a number and a name for each value in the data set. I want to be able to access each value using either the number OR the name. I have considered several possible implementations: Using two separate dictionaries, one for the data values organized by number, and one for the data values organized by name. Simply assigning two keys to the same value in a dictionary. Creating dictionaries mapping each name to the corresponding number, and vice versa Attempting to create a hash function that maps each name to a number, etc. (related to the above) Creating an object to encapsulate all three pieces of data, then using one key to map dictionary keys to the objects and simply searching the dictionary to map the other key to the object. None of these seem ideal. The first seems ugly and unmaintainable. The second also seems fragile. The third/fourth seem plausible, but seem to require either much manual specification or an overly complex implementation. Finally, the fifth loses constant-time performance for one of the lookups. In C/C++, I believe that I would use pointers to reference the same piece of data from different keys. I know that the problem is rather similar to a database lookup problem by a non-key column, however, I would like (if possible), to maintain the approximate O(1) performance of Python dictionaries. What is the most Pythonic way to achieve this data structure?

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  • Speed of QHash lookups using QStrings as keys.

    - by Ryan R.
    I need to draw a dynamic overlay on a QImage. The component parts of the overlay are defined in XML and parsed out to a QHash<QString, QPicture> where the QString is the name (such as "crosshairs") and the QPicture is the resolution independent drawing. I then draw components of the overlay as they are needed at a position determined during runtime. Example: I have 10 pictures in my QHash composing every possible element in a HUD. During a particular frame of video I need to draw 6 of them at different positions on the image. During the next frame something has changed and now I only need to draw 4 of them but 2 of those positions have changed. Now to my question: If I am trying to do this quickly, should I redefine my QHash as QHash<int, QPicture> and enumerate the keys to counteract the overhead caused by string comparisons; or are the comparisons not going to make a very big impact on performance? I can easily make the conversion to integer keys as the XML parser and overlay composer are completely separate classes; but I would like to use a consistent data structure across the application. Should I overcome my desire for consistency and re-usability in order to increase performance? Will it even matter very much if I do?

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  • Call .NET Webservice with Android

    - by Lasse P
    Hi, I know this question has been asked here before, but I don't think those answers were adequate for my needs. We have a SOAP webservice that is used for an iPhone application, but it is possible that we need an Android specific version or a proxy of the service, so we have the option to go with either SOAP or JSON. I have a few concerns about both methods: SOAP solution: Is it possible to generate java source code from a WSDL file, if so, will it include some kind of proxy class to invoke the webservice and will it work in the Android environment at all? Google has not provided any SOAP library in Android, so i need to use 3rd party, any suggestion? What about the performance/overhead with parsing and transmitting SOAP xml over the wire versus the JSON solution? JSON solution: There is a few classes in the Android sdk that will let me parse JSON, but does it support generic parsing, like if I want the result to be parsed as a complex type? Or would I need to implement that myself? I have read about 2 libraries before here on Stackoverflow, GSON an Jackson. What is the difference performance and usability (from a developers perspective) wise? Do you guys have any experince with either of those libraries? So i guess the big question is, what method to go with? I hope you can help me out. Thanks in advance :-)

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  • Forming triangles from points and relations

    - by SiN
    Hello, I want to generate triangles from points and optional relations between them. Not all points form triangles, but many of them do. In the initial structure, I've got a database with the following tables: Nodes(id, value) Relations(id, nodeA, nodeB, value) Triangles(id, relation1_id, relation2_id, relation3_id) In order to generate triangles from both nodes and relations table, I've used the following query: INSERT INTO Triangles SELECT t1.id, t2.id , t3.id, FROM Relations t1, Relations t2, Relations t3 WHERE t1.id < t2.id AND t3.id > t1.id AND ( t1.nodeA = t2.nodeA AND (t3.nodeA = t1.nodeB AND t3.nodeB = t2.nodeB OR t3.nodeA = t2.nodeB AND t3.nodeB = t1.nodeB) OR t1.nodeA = t2.nodeB AND (t3.nodeA = t1.nodeB AND t3.nodeB = t2.nodeA OR t3.nodeA = t2.nodeA AND t3.nodeB = t1.nodeB) ) It's working perfectly on small sized data. (~< 50 points) In some cases however, I've got around 100 points all related to each other which leads to thousands of relations. So when the expected number of triangles is in the hundreds of thousands, or even in the millions, the query might take several hours. My main problem is not in the select query, while I see it execute in Management Studio, the returned results slow. I received around 2000 rows per minute, which is not acceptable for my case. As a matter of fact, the size of operations is being added up exponentionally and that is terribly affecting the performance. I've tried doing it as a LINQ to object from my code, but the performance was even worse. I've also tried using SqlBulkCopy on a reader from C# on the result, also with no luck. So the question is... Any ideas or workarounds?

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  • OpenSceneGraph C++ Access Violation reading location 0x00421000

    - by Kobojunkie
    Working with OpenSceneGraph, and I keep running into this violation issue that I would appreciate some help with. The problem is with the particular line below which happens to be the first in my main function. osg::ref_ptr<osg::Node> bench = osgDB::readNodeFile("Models/test.IVE"); I have my models folder right in my directory. The error is as below. Unhandled exception at 0x68630A6C (msvcr100.dll) in OSG3D.exe: 0xC0000005: Access violation reading location 0x00421000. And this is where the problem seems to be coming up. /** Read an osg::Node from file. * Return valid osg::Node on success, * return NULL on failure. * The osgDB::Registry is used to load the appropriate ReaderWriter plugin * for the filename extension, and this plugin then handles the request * to read the specified file.*/ inline osg::Node* readNodeFile(const std::string& filename) { return readNodeFile(filename,Registry::instance()->getOptions()); } I would appreciate details on how best to tackle this kind of exception message in the future. Are there tools that make this easy to debug or are there ways to capture the exact issues and fix them? I would appreciate any help with this. My ultimate goal is to learn how to better debug C++ related issues please. With this, it means reading through the compiler error list http://msdn.microsoft.com/en-us/library/850cstw1(v=vs.71).aspx is not enough

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  • Iteration over a linq to sql query is very slow.

    - by devzero
    I have a view, AdvertView in my database, this view is a simple join between some tables (advert, customer, properties). Then I have a simple linq query to fetch all adverts for a customer: public IEnumerable<AdvertView> GetAdvertForCustomerID(int customerID) { var advertList = from advert in _dbContext.AdvertViews where advert.Customer_ID.Equals(customerID) select advert; return advertList; } I then wish to map this to modelItems for my MVC application: public List<AdvertModelItem> GetAdvertsByCustomer(int customerId) { List<AdvertModelItem> lstAdverts = new List<AdvertModelItem>(); List<AdvertView> adViews = _dataHandler.GetAdvertForCustomerID(customerId).ToList(); foreach(AdvertView adView in adViews) { lstAdverts.Add(_advertMapper.MapToModelClass(adView)); } return lstAdverts; } I was expecting to have some performance issues with the SQL, but the problem seems to be with the .ToList() function. I'm using ANTS performance profiler and it reports that the total runtime of the function is 1.400ms, and 850 of those is with the ToList(). So my question is, why does the tolist function take such a long time here?

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