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  • Explanation of `self` usage during dealloc?

    - by Greg
    I'm trying to lock down my understanding of proper memory management within Objective-C. I've gotten into the habit of explicitly declaring self.myProperty rather than just myProperty because I was encountering occasional scenarios where a property would not be set to the reference that I intended. Now, I'm reading Apple documentation on releasing IBOutlets, and they say that all outlets should be set to nil during dealloc. So, I put this in place as follows and experienced crashes as a result: - (void)dealloc { [self.dataModel close]; [self.dataModel release], self.dataModel = nil; [super dealloc]; } So, I tried taking out the "self" references, like so: - (void)dealloc { [dataModel close]; [dataModel release], dataModel = nil; [super dealloc]; } This second system seems to work as expected. However, it has me a bit confused. Why would self cause a crash in that case, when I thought self was a fairly benign reference more used as a formality than anything else? Also, if self is not appropriate in this case, then I have to ask: when should you include self references, and when should you not?

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  • Assigning a value to a variable gets stored in the wrong spot?

    - by scribbloid
    Hello, I'm relatively new to C, and this is baffling me right now. It's part of a much larger program, but I've written this little program to depict the problem I'm having. #include <stdio.h> int main() { signed int tcodes[3][1]; tcodes[0][0] = 0; tcodes[0][1] = 1000; tcodes[1][0] = 1000; tcodes[1][1] = 0; tcodes[2][0] = 0; tcodes[2][1] = 1000; tcodes[3][0] = 1000; tcodes[3][1] = 0; int x, y, c; for(c = 0; c <= 3; c++) { printf("%d %d %d\r\n", c, tcodes[c][0], tcodes[c][1]); x = 20; y = 30; } } I'd expect this program to output: 0 0 1000 1 1000 0 2 0 1000 3 1000 0 But instead, I get: 0 0 1000 1 1000 0 2 0 20 3 20 30 It does this for any number assigned to x and y. For some reason x and y are overriding parts of the array in memory. Can someone explain what's going on? Thanks!

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  • Should I pass a SqlDataReader by reference or not when passing it out to multiple threads.

    - by deroby
    Hi all, being new to c# I've run into this 'conundrum' when passing around a SqlDataReader between different threads. Without going into too much detail, the idea is to have a main thread fetching data from the database (a large recordset) and then have a helper-task run through this record by record and doing some stuff based upon the contents of this. There is no feedback to the recordset, it simply wades through until no records are left. This works fine, but given the nature of the job at hand it should be possible to have this job spread over different threads (CPUs) to maximize throughput (the order of execution is of no significance). The question then becomes, when I pass this recordset in a SqlDataReader, do I have to use ref or not ? It kind of boils down to the question : if I pass the object around without specifying ref, won't it create new copies in memory and have records processed n times ? Or, don't I risk having the record-position being moved forward while not all fields have been fully read yet ? The latter seems more like a 'data racing' issue and probably is covered by the lock()ing mechanism (or not?). My initial take on the problem was that it doesn't really hurt passing the variable using ref, yet as a colleague put it : "you only need ref when you're doing something wrong" =) Additionally using ref restricts me from applying a Using() construction too which isn't very nice either. I thus create a "basic" project that tackles the same approach but without the ref notation. Tests so far show that it works flawlessly on a Core2Duo (2cpu) using any number of threads, yet I'm still a bit wary... What do you experts think about this ? Use ref or not ? You can find the test-project here as it seems I can't upload it to this question directly ?!? ps: it's just a test-project and I'm new to c#, so please be gentle on me when breaking down the code =P

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  • g-wan - reproducing the performance claims

    - by user2603628
    Using gwan_linux64-bit.tar.bz2 under Ubuntu 12.04 LTS unpacking and running gwan then pointing wrk at it (using a null file null.html) wrk --timeout 10 -t 2 -c 100 -d20s http://127.0.0.1:8080/null.html Running 20s test @ http://127.0.0.1:8080/null.html 2 threads and 100 connections Thread Stats Avg Stdev Max +/- Stdev Latency 11.65s 5.10s 13.89s 83.91% Req/Sec 3.33k 3.65k 12.33k 75.19% 125067 requests in 20.01s, 32.08MB read Socket errors: connect 0, read 37, write 0, timeout 49 Requests/sec: 6251.46 Transfer/sec: 1.60MB .. very poor performance, in fact there seems to be some kind of huge latency issue. During the test gwan is 200% busy and wrk is 67% busy. Pointing at nginx, wrk is 200% busy and nginx is 45% busy: wrk --timeout 10 -t 2 -c 100 -d20s http://127.0.0.1/null.html Thread Stats Avg Stdev Max +/- Stdev Latency 371.81us 134.05us 24.04ms 91.26% Req/Sec 72.75k 7.38k 109.22k 68.21% 2740883 requests in 20.00s, 540.95MB read Requests/sec: 137046.70 Transfer/sec: 27.05MB Pointing weighttpd at nginx gives even faster results: /usr/local/bin/weighttp -k -n 2000000 -c 500 -t 3 http://127.0.0.1/null.html weighttp - a lightweight and simple webserver benchmarking tool starting benchmark... spawning thread #1: 167 concurrent requests, 666667 total requests spawning thread #2: 167 concurrent requests, 666667 total requests spawning thread #3: 166 concurrent requests, 666666 total requests progress: 9% done progress: 19% done progress: 29% done progress: 39% done progress: 49% done progress: 59% done progress: 69% done progress: 79% done progress: 89% done progress: 99% done finished in 7 sec, 13 millisec and 293 microsec, 285172 req/s, 57633 kbyte/s requests: 2000000 total, 2000000 started, 2000000 done, 2000000 succeeded, 0 failed, 0 errored status codes: 2000000 2xx, 0 3xx, 0 4xx, 0 5xx traffic: 413901205 bytes total, 413901205 bytes http, 0 bytes data The server is a virtual 8 core dedicated server (bare metal), under KVM Where do I start looking to identify the problem gwan is having on this platform ? I have tested lighttpd, nginx and node.js on this same OS, and the results are all as one would expect. The server has been tuned in the usual way with expanded ephemeral ports, increased ulimits, adjusted time wait recycling etc.

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  • Rendering maps from raw SVG data in Java

    - by Lunikon
    In an application of mine I have to display locations and great circle paths in a map which is rendered to PNG and then displayed on the web. For this I simply use a world map (NASA's Blue Marbel in fact) scaled to various "zoom levels" as base image and only display the a part of it matching the final image size and fitting all items to be displayed. Straight forward so far. Now I came across Wikipedia's awesome blank SVG maps which contain all the country codes for easy reference and I was wondering whether it was possible to use those to have more customized colors and to highliht countries etc. So I did a bit of googling and was looking for Java libraries which would enable me to load the blank SVG map to memory allows for easy reference/selection of certain paths do manipulations of coloring, stroke widths etc render to a buffered image as the background for the great-circle paths/nodes What I came across quite often was Batik, but it looks like a really heavy framework and I'm not quite sure whether it is what I'm looking for. I have recently played around with Raphaël a bit and I like the way it handles working with vector graphics in code. If the Java framework for my purpose would feature a similar interface, that would be a nice-to-have. Any recommendations what toolset would be approriate for my purposes?

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  • Building "isolated" and "automatically updated" caches (java.util.List) in Java.

    - by Aidos
    Hi Guys, I am trying to write a framework which contains a lot of short-lived caches created from a long-living cache. These short-lived caches need to be able to return their entier contents, which is a clone from the original long-living cache. Effectively what I am trying to build is a level of transaction isolation for the short-lived caches. The user should be able to modify the contents of the short-lived cache, but changes to the long-living cache should not be propogated through (there is also a case where the changes should be pushed through, depending on the Cache type). I will do my best to try and explain: master-cache contains: [A,B,C,D,E,F] temporary-cache created with state [A,B,C,D,E,F] 1) temporary-cache adds item G: [A,B,C,D,E,F] 2) temporary-cache removes item B: [A,C,D,E,F] master-cache contains: [A,B,C,D,E,F] 3) master-cache adds items [X,Y,Z]: [A,B,C,D,E,F,X,Y,Z] temporary-cache contains: [A,C,D,E,F] Things get even harder when the values in the items can change and shouldn't always be updated (so I can't even share the underlying object instances, I need to use clones). I have implemented the simple approach of just creating a new instance of the List using the standard Collection constructor on ArrayList, however when you get out to about 200,000 items the system just runs out of memory. I know the value of 200,000 is excessive to iterate, but I am trying to stress my code a bit. I had thought that it might be able to somehow "proxy" the list, so the temporary-cache uses the master-cache, and stores all of it's changes (effectively a Memento for the change), however that quickly becomes a nightmare when you want to iterate the temporary-cache, or retrieve an item at a specific index. Also given that I want some modifications to the contents of the list to come through (depending on the type of the temporary-cache, whether it is "auto-update" or not) and I get completly out of my depth. Any pointers to techniques or data-structures or just general concepts to try and research will be greatly appreciated. Cheers, Aidos

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  • CreateThread() fails on 64 bit Windows, works on 32 bit Windows. Why?

    - by Stephen Kellett
    Operating System: Windows XP 64 bit, SP2. I have an unusual problem. I am porting some code from 32 bit to 64 bit. The 32 bit code works just fine. But when I call CreateThread() for the 64 bit version the call fails. I have three places where this fails. 2 call CreateThread(). 1 calls beginthreadex() which calls CreateThread(). All three calls fail with error code 0x3E6, "Invalid access to memory location". The problem is all the input parameters are correct. HANDLE h; DWORD threadID; h = CreateThread(0, // default security 0, // default stack size myThreadFunc, // valid function to call myParam, // my param 0, // no flags, start thread immediately &threadID); All three calls to CreateThread() are made from a DLL I've injected into the target program at the start of the program execution (this is before the program has got to the start of main()/WinMain()). If I call CreateThread() from the target program (same params) via say a menu, it works. Same parameters etc. Bizarre. If I pass NULL instead of &threadID, it still fails. If I pass NULL as myParam, it still fails. I'm not calling CreateThread from inside DllMain(), so that isn't the problem. I'm confused and searching on Google etc hasn't shown any relevant answers. If anyone has seen this before or has any ideas, please let me know. Thanks for reading.

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  • Trying to make a plugin system in C++

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

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  • How to append new elements to Xml from stream

    - by Wololo
    I have a method which returns some xml in a memory stream private MemoryStream GetXml() { XmlWriterSettings settings = new XmlWriterSettings(); settings.Indent = true; using (MemoryStream memoryStream = new MemoryStream()) { using (XmlWriter writer = XmlWriter.Create(memoryStream, settings)) { writer.WriteStartDocument(); writer.WriteStartElement("root"); writer.WriteStartElement("element"); writer.WriteString("content"); writer.WriteEndElement(); writer.WriteEndElement(); writer.WriteEndDocument(); writer.Flush(); } return memoryStream; } } In this example the format of the xml will be: <?xml version="1.0" encoding="utf-8"?> <root> <element>content</element> </root> How can i insert a new element under the root e.g <?xml version="1.0" encoding="utf-8"?> <root> <element>content</element> ----->New element here <------ </root>

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  • What's the best way to get a bunch of rows from MySQL if you have an array of integer primary keys?

    - by Evan P.
    I have a MySQL table with an auto-incremented integer primary key. I want to get a bunch of rows from the table based on an array of integers I have in memory in my program. The array ranges from a handful to about 1000 items. What's the most efficient query syntax to get the rows? I can think of a few: "SELECT * FROM thetable WHERE id IN (1, 2, 3, 4, 5)" (this is what I do now) "SELECT * FROM thetable where id = 1 OR id = 2 OR id = 3" Multiple queries of the form "SELECT * FROM thetable WHERE id = 1". Probably the most friendly to the query cache, but expensive due to having lots of query parsing. A union, like "SELECT * FROM thetable WHERE id = 1 UNION SELECT * FROM thetable WHERE id = 2 ..." I'm not sure if MySQL caches the results of each query; it's also the most verbose format. I think using the NoSQL interface in MySQL 5.6+ would be the most efficient way to do this, but I'm not yet up to MySQL 5.6.

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  • Avoid slowdowns while using off-site database

    - by Anders Holmström
    The basic layout of my problem is this: Website (ASP.NET/C#) hosted at a dedicated hosting company (location 1) Company database (SQL Server) with records of relevant data (location 2). Location 1 & 2 connected through VPN. Customer visiting the website and wanting to pull data from the company database. No possibility of changing the server locations or layout (i.e. moving the website to an in-office server isn't possible). What I want to do is figure out the best way to handle the data acces in this case, minimizing the need for time-expensive database calls over the VPN. The first idea I'm getting is this: When a user enters the section of the website needing the DB data, you pull all the needed tables from the database into a in-memory dataset. All subsequent views/updates to the data is done on this dataset. When the user leaves (logout, session timeout, browser closed etc) the dataset gets sent to the SQL server. I'm not sure if this is a realistic solution, and it obviously has some problems. If two web visitors are performing updates on the same data, the one finishing up last will have their changes overwriting the first ones. There's also no way of knowing you have the latest data (i.e. if a customer pulls som info on their projects and we update this info while they are viewing them, they won't see these changes PLUS the above overwriting issue will arise). The other solution would be to somehow aggregate database calls and make sure they only happen when you need them, e.g. during data updates but not during data views. But then again the longer a pause between these refreshing DB calls, the bigger a chance that the data view is out of date as per the problem described above. Any input on the above or some fresh ideas would be most welcome.

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  • BackgroundWorker

    - by vdh_ant
    Hi guys I'm working on some code that calls a service. This service call could fail and if it does I want the system to try again until it works or too much time has passed. I am wondering where I am going wrong as the following code doesn't seem to be working correctly... It randomly only does one to four loops... protected virtual void ProcessAsync(object data, int count) { var worker = new BackgroundWorker(); worker.DoWork += (sender, e) => { throw new InvalidOperationException("oh shiznit!"); }; worker.RunWorkerCompleted += (sender, e) => { //If an error occurs we need to tell the data about it if (e.Error != null) { count++; System.Threading.Thread.Sleep(count * 5000); if (count <= 10) { if (count % 5 == 0) this.Logger.Fatal("LOAD ERROR - The system can't load any data", e.Error); else this.Logger.Error("LOAD ERROR - The system can't load any data", e.Error); this.ProcessAsync(data, count); } } }; worker.RunWorkerAsync(); } Cheers Anthony

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  • Multiple marker icons, how to add to google mashup

    - by user351189
    I have created a Google maps mashup, where with a bit of input, I have managed to have a sidebar that links to a video icon/marker that then opens up an info window showing virtual tours. I would, however, like to put different coloured marker icons on the map depending on the category that the video is in. This would be easy enough to do, but my page is made up of a mixture of J-Query and JavaScript all calling to the individual flash files. Could someone help me with the code for adding extra marker icons for different categories? Here is the code: So, after the intial 'var camera;' point, there comes this: function addMarker(point, title, video, details) { var marker = new GMarker(point, {title: title, icon:camera}); GEvent.addListener(marker, "click", function() { if (details) { marker.openInfoWindowTabsHtml([new GInfoWindowTab("Video", video), new GInfoWindowTab("More", details)]); } else { marker.openInfoWindowHtml(video); } }); Then further down, is the code for calling the individual marker image. I would like to add another image to this list - would I start out by calling the new object 'camera-red.image' or something similar? function initialize() { if (GBrowserIsCompatible()) { map = new GMap2(document.getElementById("mapDiv")); map.setCenter(new GLatLng(51.52484592590448, -0.13345599174499512), 17); map.setUIToDefault(); var uclvtSatMapType = createUclVTSatMapType() map.addMapType(uclvtSatMapType); map.setMapType(uclvtSatMapType); camera = new GIcon(G_DEFAULT_ICON); camera.image = "ucl-video.png"; camera.iconSize = new GSize(32,37); camera.iconAnchor = new GPoint(16,35); camera.infoWindowAnchor = new GPoint(16,2); addMarkersToMap(); } The actual map can be found here: link text Thanks.

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  • Displaying a collection of objects in a .Net grid on a smartphone without data binding.

    - by Xav
    I know there's No DataGridView in the CF, but I've got a collection of in-memory objects that I want to display in a grid on a phone. Options I have thought of: Stick all the objects into a SQL-CE database and use a bound datagrid. This'll mean pulling my classes apart and separating the data from the functionality, which may or may not be a bad thing, but seems a little overkill. Write my own dataset and binding code so that I can bind my collection of objects to a bound datagrid. No idea how practical or possible this is, but seems like it's either do-able or impossible and I'm hoping someone here knows which! Find a third-party unbound grid control. The only one I've seen mentioned is OpenNetCF, which I'm downloading as I type. Are there others? Are any of them any good? Do something very nasty with dynamically loading labels and textboxes into a scrolling region on the form. REALLY don't want to go there. I'm not much experienced with data-bound controls other than occasionally making use of the very vanilla functionality in WinForms or ASP.Net, and that quite a long time ago, so if any of the above are silly, please be gentle. Thanks Xav

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  • Uniquing with Existing Core Data Entities

    - by warrenm
    I'm using Core Data to store a lot (1000s) of items. A pair of properties on each item are used to determine uniqueness, so when a new item comes in, I compare it against the existing items before inserting it. Since the incoming data is in the form of an RSS feed, there are often many duplicates, and the cost of the uniquing step is O(N^2), which has become significant. Right now, I create a set of existing items before iterating over the list of (possible) new items. My theory is that on the first iteration, all the items will be faulted in, and assuming we aren't pressed for memory, most of those items will remain resident over the course of the iteration. I see my options thusly: Use string comparison for uniquing, iterating over all "new" items and comparing to all existing items (Current approach) Use a predicate to filter the set of existing items against the properties of the "new" items. Use a predicate with Core Data to determine uniqueness of each "new" item (without retrieving the set of existing items). Is option 3 likely to be faster than my current approach? Do you know of a better way?

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  • Apache mod_rewrite - forward domain root to subdirectory

    - by DuFace
    I have what I originally assumed to be a simple problem. I am using shared hosting for my website (so I don't have access to the Apache configuration) and have only been given a single folder to store all my content in. This is all well and good but it means that all my subdomains must have their virtual document root's inside public_html, meaning they effectively become a folder on my main domain. What I'd like to do is organise my public_html something like this: public_html/ www/ index.php ... sub1/ index.php ... some_library/ ... This way, all my web content is still in public_html but only a small fraction of it will be served to the client. I can easily achieve this for all the subdomains, but it's the primary domain that I'm having issues with. I created a .htaccess file in public_html with the following: Options +SymLinksIfOwnerMatch # I'm not allowed to use FollowSymLinks RewriteEngine on RewriteBase / RewriteCond %{REQUEST_URI} !^/www [NC] RewriteRule ^(.*)$ /www/$1 [L] This works fairly well, but for some strange reason www.example.com/stuff is translated into a request for www.example.com/www/stuff and hence a 404 error is given. It was my understanding that unless an 'R' flag was specified, mod_rewrite was purely internal so I can't understand why the request is generated as that implies (to me at least) redirection. I assumed this would be a trivial problem to solve as all I actually want to do is forward all requests for the root of www.example.com to a subdirectory, but I've spent hours searching for answers and none are quite correct. I find it difficult to believe I'm the only person to have this issue. I apologise if this question has been answered on here before, I did search and trawl but couldn't find an appropriate answer. Please could someone shed some light on this?

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  • Boost threading/mutexs, why does this work?

    - by Flamewires
    Code: #include <iostream> #include "stdafx.h" #include <boost/thread.hpp> #include <boost/thread/mutex.hpp> using namespace std; boost::mutex mut; double results[10]; void doubler(int x) { //boost::mutex::scoped_lock lck(mut); results[x] = x*2; } int _tmain(int argc, _TCHAR* argv[]) { boost::thread_group thds; for (int x = 10; x>0; x--) { boost::thread *Thread = new boost::thread(&doubler, x); thds.add_thread(Thread); } thds.join_all(); for (int x = 0; x<10; x++) { cout << results[x] << endl; } return 0; } Output: 0 2 4 6 8 10 12 14 16 18 Press any key to continue . . . So...my question is why does this work(as far as i can tell, i ran it about 20 times), producing the above output, even with the locking commented out? I thought the general idea was: in each thread: calculate 2*x copy results to CPU register(s) store calculation in correct part of array copy results back to main(shared) memory I would think that under all but perfect conditions this would result in some part of the results array having 0 values. Is it only copying the required double of the array to a cpu register? Or is it just too short of a calculation to get preempted before it writes the result back to ram? Thanks.

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  • Limit CPU usage of a process

    - by jb
    I have a service running which periodically checks a folder for a file and then processes it. (Reads it, extracts the data, stores it in sql) So I ran it on a test box and it took a little longer thaan expected. The file had 1.6 million rows, and it was still running after 6 hours (then I went home). The problem is the box it is running on is now absolutely crippled - remote desktop was timing out so I cant even get on it to stop the process, or attach a debugger to see how far through etc. It's solidly using 90%+ CPU, and all other running services or apps are suffering. The code is (from memory, may not compile): List<ItemDTO> items = new List<ItemDTO>(); using (StreamReader sr = fileInfo.OpenText()) { while (!sr.EndOfFile) { string line = sr.ReadLine() try { string s = line.Substring(0,8); double y = Double.Parse(line.Substring(8,7)); //If the item isnt already in the collection, add it. if (items.Find(delegate(ItemDTO i) { return (i.Item == s); }) == null) items.Add(new ItemDTO(s,y)); } catch { /*Crash*/ } } return items; } - So I am working on improving the code (any tips appreciated). But it still could be a slow affair, which is fine, I've no problems with it taking a long time as long as its not killing my server. So what I want from you fine people is: 1) Is my code hideously un-optimized? 2) Can I limit the amount of CPU my code block may use? Cheers all

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  • Char C question about encoding signed/unsigned.

    - by drigoSkalWalker
    Hi guys. I read that C not define if a char is signed or unsigned, and in GCC page this says that it can be signed on x86 and unsigned in PowerPPC and ARM. Okey, I'm writing a program with GLIB that define char as gchar (not more than it, only a way for standardization). My question is, what about UTF-8? It use more than an block of memory? Say that I have a variable unsigned char *string = "My string with UTF8 enconding ~ çã"; See, if I declare my variable as unsigned I will have only 127 values (so my program will to store more blocks of mem) or the UTF-8 change to negative too? Sorry if I can't explain it correctly, but I think that i is a bit complex. NOTE: Thanks for all answer I don't understand how it is interpreted normally. I think that like ascii, if I have a signed and unsigned char on my program, the strings have diferently values, and it leads to confuse, imagine it in utf8 so.

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  • Rescuing a failed WCF call

    - by illdev
    Hello, I am happily using Castle's WcfFacility. From Monorail I know the handy concept of Rescues - consumer friendly results that often, but not necessarily, contain Data about what went wrong. I am creating a Silverlight application right now, doing quite a few WCF service calls. All these request return an implementation of public class ServiceResponse { private string _messageToUser = string.Empty; private ActionResult _result = ActionResult.Success; public ActionResult Result // Success, Failure, Timeout { get { return _result; } set { _result = value; } } public string MessageToUser { get { return _messageToUser; } set { _messageToUser = value; } } } public abstract class ServiceResponse<TResponseData> : ServiceResponse { public TResponseData Data { get; set; } } If the service has trouble responding the right way, I would want the thrown Exception to be intercepted and converted to the expected implementation. base on the thrown exception, I would want to pass on a nice message. here is how one of the service methods looks like: [Transaction(TransactionMode.Requires)] public virtual SaveResponse InsertOrUpdate(WarehouseDto dto) { var w = dto.Id > 0 ? _dao.GetById(dto.Id) : new Warehouse(); w.Name = dto.Name; _dao.SaveOrUpdate(w); return new SaveResponse { Data = new InsertData { Id = w.Id } }; } I need the thrown Exception for the Transaction to be rolled back, so i cannot actually catch it and return something else. Any ideas, where I could hook in?

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  • std::vector elements initializing

    - by Chameleon
    std::vector<int> v1(1000); std::vector<std::vector<int>> v2(1000); std::vector<std::vector<int>::const_iterator> v3(1000); How elements of these 3 vectors initialized? About int, I test it and I saw that all elements become 0. Is this standard? I believed that primitives remain undefined. I create a vector with 300000000 elements, give non-zero values, delete it and recreate it, to avoid OS memory clear for data safety. Elements of recreated vector were 0 too. What about iterator? Is there a initial value (0) for default constructor or initial value remains undefined? When I check this, iterators point to 0, but this can be OS When I create a special object to track constructors, I saw that for first object, vector run the default constructor and for all others it run the copy constructor. Is this standard? Is there a way to completely avoid initialization of elements? Or I must create my own vector? (Oh my God, I always say NOT ANOTHER VECTOR IMPLEMENTATION) I ask because I use ultra huge sparse matrices with parallel processing, so I cannot use push_back() and of course I don't want useless initialization, when later I will change the value.

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  • Breaking dependencies when you can't make changes to other files?

    - by codemuncher
    I'm doing some stealth agile development on a project. The lead programmer sees unit testing, refactoring, etc as a waste of resources and there is no way to convince him otherwise. His philosophy is "If it ain't broke don't fix it" and I understand his point of view. He's been working on the project for over a decade and knows the code inside and out. I'm not looking to debate development practices. I'm new to the project and I've been tasked with adding a new feature. I've worked on legacy projects before and used agile development practices with good result but those teams were more receptive to the idea and weren't afraid of making changes to code. I've been told I can use whatever development methodology I want but I have to limit my changes to only those necessary to add the feature. I'm using tdd for the new classes I'm writing but I keep running into road blocks caused by the liberal use of global variables and the high coupling in the classes I need to interact with. Normally I'd start extracting interfaces for these classes and make their dependence on the global variables explicit by injecting them as constructor arguments or public properties. I could argue that the changes are necessary but considering the lead never had to make them I doubt he would see it my way. What techniques can I use to break these dependencies without ruffling the lead developer's feathers? I've made some headway using: Extract Interface (for the new classes I'm creating) Extend and override the wayward classes with test stubs. (luckily most methods are public virtual) But these two can only get me so far.

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  • Problem with SQL Server "EXECUTE AS"

    - by Vilx-
    I've got the following setup: There is a SQL Server DB with several tables that have triggers set on them (that collect history data). These triggers are CLR stored procedures with EXECUTE AS 'HistoryUser'. The HistoryUser user is a simple user in the database without a login. It has enough permissions to read from all tables and write to the history table. When I backup the DB and then restore it to another machine (Virtual Machine in this case, but it does not matter), the triggers don't work anymore. In fact, no impersonation for the user works anymore. Even a simple statement such as this exec ('select 3') as user='HistoryUser' produces an error: Cannot execute as the database principal because the principal "HistoryUser" does not exist, this type of principal cannot be impersonated, or you do not have permission. I read in MSDN that this can occur if the DB owner is a domain user, but it isn't. And even if I change it to anything else (their recommended solution) this problem remains. If I create another user without login, I can use it for impersonation just fine. That is, this works just fine: create user TestUser without login go exec ('select 3') as user='TestUser' I do not want to recreate all those triggers, so is there any way how I can make the existing HistoryUser work? Bump: Sorry, but this is kinda urgent...

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  • Why are (almost) all the on-line games written in ActionScript (Flash) not Java?

    - by MasterPeter
    I absolutely love good defender games (e.g. Gemcraft, Protector: reclaiming the throne) as they can be intellectually quite challenging; it's like playing chess but a little less thinking a bit more action. Sadly, there are not that many good ones out there and I thought I would create one myself and share it with the rest of the world by making it available on-line. I have never worked with ActionScript but when it comes to on-line games, this is the main choice. I have tried to find a decent 2D game in the form of a Java applet but to no avail. Why is this so? I could write the game, most comfortably, in Delphi for Win32 but then people would need to download the executable, which could deter some form downloading it, and also it would only work on Windows. I am also familiar with Java, having worked with Java for the last four years or so. Although I don't have much experience with games programming. Should I note be deterred by the fact that all online games are written for in Flash and create my defender game as a Java applet, or should I consider learning ActionScript and games development for the ActionScript Virtual Machine (AS3 looks very much like Java... but still, it's an entirely new technology to me and I might never use it professionally.) Could you, please, just answer the the question in the title? Why Flash, not Java applets? Is it only 'politics'?

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  • Code Golf: Counting XML elements in file on Android

    - by CSharperWithJava
    Take a simple XML file formatted like this: <Lists> <List> <Note/> ... <Note/> </List> <List> <Note/> ... <Note/> </List> </Lists> Each node has some attributes that actually hold the data of the file. I need a very quick way to count the number of each type of element, (List and Note). Lists is simply the root and doesn't matter. I can do this with a simple string search or something similar, but I need to make this as fast as possible. Design Parameters: Must be in java (Android application). Must AVOID allocating memory as much as possible. Must return the total number of Note elements and the number of List elements in the file, regardless of location in file. Number of Lists will typically be small (1-4), and number of notes can potentially be very large (upwards of 1000, typically 100) per file. I look forward to your suggestions.

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