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  • Is there any danger in calling free() or delete instead of delete[]? [closed]

    - by Matt Joiner
    Possible Duplicate: ( POD )freeing memory : is delete[] equal to delete ? Does delete deallocate the elements beyond the first in an array? char *s = new char[n]; delete s; Does it matter in the above case seeing as all the elements of s are allocated contiguously, and it shouldn't be possible to delete only a portion of the array? For more complex types, would delete call the destructor of objects beyond the first one? Object *p = new Object[n]; delete p; How can delete[] deduce the number of Objects beyond the first, wouldn't this mean it must know the size of the allocated memory region? What if the memory region was allocated with some overhang for performance reasons? For example one could assume that not all allocators would provide a granularity of a single byte. Then any particular allocation could exceed the required size for each element by a whole element or more. For primitive types, such as char, int, is there any difference between: int *p = new int[n]; delete p; delete[] p; free p; Except for the routes taken by the respective calls through the delete-free deallocation machinery?

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  • Dynamic programming in VB

    - by Rahul Jain
    Hello Everybody, We develop applications for SAP using their SDK. SAP provides a SDK for changing and handling events occuring in the user interface. For example, with this SDK we can catch a click on a button and do something on the click. This programming can be done either VB or C#. This can also be used to create new fields on the pre-existing form. We have developed a specific application which allows users to store the definition required for new field in a database table and the fields are created at the run time. So far, this is good. What we require now is that the user should be able to store the validation code for the field in the database and the same should be executed on the run time. Following is an example of such an event: Private Sub SBO_Application_ItemEvent(ByVal FormUID As String, ByRef pVal As SAPbouiCOM.ItemEvent, ByRef BubbleEvent As Boolean) Handles SBO_Application.ItemEvent Dim oForm As SAPbouiCOM.Form If pVal.FormTypeEx = "ACC_QPLAN" Then If pVal.EventType = SAPbouiCOM.BoEventTypes.et_LOST_FOCUS And pVal.BeforeAction = False Then oProdRec.ItemPressEvent(pVal) End If End If End Sub Public Sub ItemPressEvent(ByRef pVal As SAPbouiCOM.ItemEvent) Dim oForm As SAPbouiCOM.Form oForm = oSuyash.SBO_Application.Forms.GetForm(pVal.FormTypeEx, pVal.FormTypeCount) If pVal.EventType = SAPbouiCOM.BoEventTypes.et_LOST_FOCUS And pVal.BeforeAction = False Then If pVal.ItemUID = "AC_TXT5" Then Dim CardCode, ItemCode As String ItemCode = oForm.Items.Item("AC_TXT2").Specific.Value CardCode = oForm.Items.Item("AC_TXT0").Specific.Value UpdateQty(oForm, CardCode, ItemCode) End If End If End Sub So, what we need in this case is to store the code given in the ItemPressEvent in a database, and execute this in runtime. I know this is not straight forward thing. But I presume there must be some ways of getting these kind of things done. The SDK is made up of COM components. Thanks & Regards, Rahul Jain

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  • SSRS - Oracle DB, Passing Date parameter

    - by davidl98
    Using SSRS with an Oracle Database. I need to prompt the user when running the report to enter a date for report. What is the best way to add in the parameter in my SSRS Report. Having problem finding the right date format. under the "Report Parameter" menu, I have setup the Report Parameters using the DateTime Datatype. Keep getting this error "ORA-01843: Not a Valid Month" Thank you for your help. Select a.OPR_Name, a.OPR, a.Trans_Desc, a.Trans_Start_Date, Cast(a.S_Date as date) as S_Date, Sum(a.Duration) as T From ( Select US_F.OPR_Name, ITH_F.OPR, ITH_F.ITH_RID, ITH_F.TRANSACT, Transact.DESC_1 as Trans_Desc, To_CHAR(ITH_F.Start_Time,'DD-Mon-YY') as Trans_Start_Date, To_CHAR(ITH_F.Start_Time,'MM/DD/YYYY') as S_Date, Substr(To_CHAR(ITH_F.Start_Time,'HH24:MI'),1,6) as Start_Time, To_CHAR(ITH_F.End_Time,'DD-Mon-YY') as Trans_End_Date, Substr(To_CHAR(ITH_F.End_Time,'HH24:MI'),1,6) as End_Time, Cast(Case When To_CHAR(ITH_F.Start_Time,'DD-Mon-YY') = To_CHAR(ITH_F.End_Time,'DD-Mon-YY') Then (((To_CHAR(ITH_F.End_Time,'SSSSS') - To_CHAR(ITH_F.Start_Time,'SSSSS')) / 60))/60 Else ((86399 - (To_CHAR(ITH_F.Start_Time,'SSSSS')) + To_CHAR(ITH_F.End_Time,'SSSSS'))/60)/60 End as Decimal(3,1)) as Duration from Elite_76_W1.ITH_F Left Join Elite_76_W1.Transact on Transact.Transact = ITH_F.Transact Left Join Elite_76_W1.US_F on US_F.OPR = ITH_F.OPR Where ITH_F.TRANSACT not in ('ASN','QC','LGOT') ) a Where a.S_Date = @Event_Date Having Sum(a.Duration) < 0 Group By a.OPR_Name, a.OPR, a.Trans_Desc, a.Trans_Start_Date, a.S_Date Order by a.OPR_Name

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  • best practice for directory polling

    - by Hieu Lam
    Hi all, I have to do batch processing to automate business process. I have to poll directory at regular interval to detect new files and do processing. While old files is being processed, new files can come in. For now, I use quartz scheduler and thread synchronization to ensure that only one thread can process files. Part of the code are: application-context.xml <bean id="methodInvokingJob" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean" <property name="targetObject" ref="documentProcessor" / <property name="targetMethod" value="processDocuments" / </bean DocumentProcessor ..... public void processDocuments() { LOG.info(Thread.currentThread().getName() + " attempt to run."); if (!processing) { synchronized (this) { try { processing = true; LOG.info(Thread.currentThread().getName() + " is processing"); List xmlDocuments = documentManager.getFileNamesFromFolder(incomingFolderPath); // loop over the files and processed unlock files. for (String xmlDocument : xmlDocuments) { processDocument(xmlDocument); } } finally { processing = false; } } } } For the current code, I have to prevent other thread to process files when one thread is processing. Is that a good idea ? or we support multi-threaded processing. In that case how can I know which files is being process and which files has just arrived ? Any idea is really appreciated.

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  • Table design issues - should I create separate fields or store as a blob

    - by Ali
    Hi guys I'm working on my web based ordering system and we would like to maintain a kind of task history for each of our orders. A hsitory in the sense that we would like to maintain a log of who did what on an order like lets say an order has been entered - we would like to know if the order was acknowledged for an example. Or lets say somebody followed up on the order - etc. Consider that there are numerous situations like this for each order would it be wise to create a schema on the lines of: Orders ID - title - description - date - is_ack - is_follow - ack_by ..... That accounts to a lot of fields - on teh other hand I could have one LongText field called 'history' and fill it with a serialised object holding all the information. However in the latter case I can't run a query to lets say retrieve all orders that have not been acknowledged and stuff like that. With time requirements woudl change and I would be required to modify it to allow for more detailed tracking and that is why I need to set up a way which would be feasible to scale upon yet I don't want to be restricted on the SQL side too much.

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  • jQuery filename manipulation

    - by Adi
    Hi all, I am trying to do a fancy blur/fade effect (which means i need 2 images) but I only want to load 1 in the HTML (in case js is not active) and add the other filename via jQuery (copying and renaming the file/src) The pure html is along the lines of: <div id="work"> <div> <img src="css/images/abc1.jpg" width="360" height="227" alt="" /> </div> <div> <img src="css/images/xyz1.jpg" width="360" height="227" alt="" /> </div> </div> But the html after jquery has manipulated the DOM needs to be like: <div id="work"> <div> <img src="css/images/abc0.jpg" width="360" height="227" alt="" /> <img src="css/images/abc1.jpg" width="360" height="227" alt="" /> </div> <div> <img src="css/images/xyz0.jpg" width="360" height="227" alt="" /> <img src="css/images/xyz1.jpg" width="360" height="227" alt="" /> </div> </div> The question is, what is the jQuery to clone/copy the relative images and then rename the src? Any help would be much appreicated. A.

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  • Method for finding memory leak in large Java heap dumps

    - by Rickard von Essen
    I have to find a memory leak in a Java application. I have some experience with this but would like advice on a methodology/strategy for this. Any reference and advice is welcome. About our situation: Heap dumps are larger than 1 GB We have heap dumps from 5 occasions. We don't have any test case to provoke this. It only happens in the (massive) system test environment after at least a weeks usage. The system is built on a internally developed legacy framework with so many design flaws that they are impossible to count them all. Nobody understands the framework in depth. It has been transfered to one guy in India who barely keeps up with answering e-mails. We have done snapshot heap dumps over time and concluded that there is not a single component increasing over time. It is everything that grows slowly. The above points us in the direction that it is the frameworks homegrown ORM system that increases its usage without limits. (This system maps objects to files?! So not really a ORM) Question: What is the methodology that helped you succeed with hunting down leaks in a enterprise scale application?

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  • JTable listener problem

    - by newbie123
    I added a mouse clicked listner to my jtable, when i double click the row, will pop up an window accordingly. jTable.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent e) { double amount = Double.parseDouble(jTable.getValueAt(getSelectedRow(), 4).toString()); String remarks = jTable.getValueAt(getSelectedRow(), 3).toString(); String transactionID = jTable.getValueAt(getSelectedRow(), 1).toString(); new EditFrame(...) } }); This code I used to retrieve the row selected row. public int getSelectedRow() { jTable.getSelectionModel().addListSelectionListener( new ListSelectionListener() { public void valueChanged(ListSelectionEvent event) { int viewRow = jTable.getSelectedRow(); selectedRow = viewRow; System.out.println(viewRow); } }); return selectedRow; } In my case, I realised when I clicked the second row in the first time, I get null for selectedRow, only when I select first row then second row, I then can get the correct data. And If I removed the mouse listener the problem then be solved. Is it because I doing something wrong at the mouse click listener?

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  • Objective-C object release and allocation timing

    - by ryanjm.mp
    The code for this question is too long to be of any use. But I'm pretty sure my problem has to do with releasing a class. I have a helper class, ConnectionHelper.h/.m, that handles a NSURLConnection for me. Basically, I give it the URL I want and it returns the data (it happens to do a quick json parse on it too). It has a delegate which I set to the calling class (in this case: DownloadViewController). When it finishes the download, it calls [delegate didFinishParseOf:objectName withDictionary:dictionary];. Then in DownloadViewController I release ConnectionHelper and alloc a new one in order to download the next object. My problem is, I do this once, and then it creates the connection for the second one, and then my program just crashes. After this call: [[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookieAcceptPolicy:NSHTTPCookieAcceptPolicyNever]; NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; Then I don't think any of the following methods are called: - (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error - (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge So am I right in that I'm not releasing something? When I release it the first time, the dealloc function isn't being called. Is there a way I can "force" it to deallocate? Do I need to force it to? I didn't think it would matter since I allocating a new ConnectionHelper for the new call. How else would they overlap / conflict with each other? Thank you.

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  • Extracting bool from istream in a templated function

    - by Thomas Matthews
    I'm converting my fields class read functions into one template function. I have field classes for int, unsigned int, long, and unsigned long. These all use the same method for extracting a value from an istringstream (only the types change): template <typename Value_Type> Value_Type Extract_Value(const std::string& input_string) { std::istringstream m_string_stream; m_string_stream.str(input_string); m_string_stream.clear(); m_string_stream >> value; return; } The tricky part is with the bool (Boolean) type. There are many textual representations for Boolean: 0, 1, T, F, TRUE, FALSE, and all the case insensitive combinations Here's the questions: What does the C++ standard say are valid data to extract a bool, using the stream extraction operator? Since Boolean can be represented by text, does this involve locales? Is this platform dependent? I would like to simplify my code by not writing my own handler for bool input. I am using MS Visual Studio 2008 (version 9), C++, and Windows XP and Vista.

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  • Is there something like a "long running offline transaction" for NHibernate or any other ORM?

    - by Vilx-
    In essence this is a followup of this question. I'm beginning to feel that I should give up the whole idea, but I'll give it one more shot. What I want is pretty much like a DB transaction. It should track my changes to the DB and then in the end allow me to either commit or rollback them. If I insert an object, I should get it back in my next (appropriate) SELECT query. If I delete it, future SELECT queries should not return it. Etc. But there is one catch - this transaction would be very long running. It would start when the user opened a form (I'm talking about Windows Forms here), and the commit/rollback would be when the user closed it(with OK/Cancel). So it could take anywhere between seconds and days. This requirement rules out a standard DB transaction because that would lock the tables/rows it touched, and other users wouldn't be able to use the system. Also the transaction should not commit ANY changes to the DB until it was really committed. So if one user makes some changes, others don't see them until OK button is hit. This prevents errors in case the computer crashes or is disconnected from the network. I'm quite OK if the solution puts constraints on my model (I'm using MSSQL 2008, btw). I can design the DB/code any way I like. I'm also fine with the idea that a commit could fail because someone already modified one of the objects my transaction touched. Is there anything like this? I looked at NHibernate.Burrow, but I'm not sure that that's the thing I want. Added: It's the very beginning of the project so I'm not tied to NHibernate. I started out with it but I can still change easily.

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  • QT- QImage and multi-threading problem.

    - by umanga
    Greetings all, Please refer to image at : http://i48.tinypic.com/316qb78.jpg We are developing an application to extract cell edges from MRC images from electron microscope. MRC file format stores volumetric pixel data (http://en.wikipedia.org/wiki/Voxel) and we simply use 3D char array(char***) to load and store data (gray scale values) from a MRC file. As shown in the image,there are 3 viewers to display XY,YZ and ZX planes respectively. Scrollbars on the top of the viewers use to change the image slice along an axis. Here is the steps we do when user changes the scrollbar position. 1) get the new scrollbar value.(this is the selected slice) 2) for the relavant plane (YZ,XY or ZX), generate (char* slice;) array for the selected slice by reading 3D char array (char***) 3) Create a new QImage* (Format_RGB888) and set pixel values by reading 'slice' (using img-setPixel(x,y,c);) 4) This new QImage* is painted in the paintEvent() method. We are going to execute "edge-detection" process in a seperate thread since it is an intensive process.During this process we need to draw detected curve (set of pixels) on top of above QImage*.(as a layer).This means we need to call drawPoint() methods outside the QT thread. Is it the best wayto use QImage for this case? What is the best way to execute QT drawing methods from another thread? thanks in advance,

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  • Create win task to run once and delete immediately using C#

    - by pencilslate
    Here is the use case: - Create a new win task, run immediately and once complete, delete the task. Here is basic code to create a task using C#. using (TaskService ts = new TaskService(null)) { string projectName = "runnowtest" + Guid.NewGuid().ToString(); //create new task TaskDefinition td = ts.NewTask(); Trigger mt = null; //setup task as Registration trigger mt = td.Triggers.AddNew(TaskTriggerType.Registration); mt.StartBoundary = DateTime.Now; //delete the task 1 minute after the program ends td.Settings.DeleteExpiredTaskAfter = new TimeSpan(0, 1, 0); //run the notepad++ in the task td.Actions.Add(new ExecAction("notepad.exe")); //register task Task output = ts.RootFolder.RegisterTaskDefinition(projectName, td); //check output Console.WriteLine(output != null ? "Task created" : "Task not created"); } The API doesn't seem to have a property/flag to mark task as run once. I am trying to ensure the above task runs only once and deletes immediately after that. Any thoughts are much appreciated!

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  • Should an Event that has no arguments define its own custom EventArgs or simply use System.EventArgs

    - by Mike Rosenblum
    I have an event that is currently defined with no event arguments. That is, the EventArgs it sends is EventArgs.Empty. In this case, it is simplest to declare my Event handler as: EventHandler<System.EventArgs> MyCustomEvent; I do not plan on adding any event arguments to this event, but it is possible that any code could need to change in the future. Therefore, I am leaning towards having all my events always create an empty event args type that inheretis from System.EventArgs, even if there are no event args currently needed. Something like this: public class MyCustomEventArgs : EventArgs { } And then my event definition becomes the following: EventHandler<MyCustomEventArgs> MyCustomEvent; So my question is this: is it better to define my own MyCustomEventArgs, even if it does not add anything beyond inheriting from System.EventArgs, so that event arguments could be added in the future more easily? Or is it better to explicitly define my event as returning System.EventArgs, so that it is clearer to the user that there are no extra event args? I am leaning towards creating custom event arguments for all my events, even if the event arguments are empty. But I was wondering if others thought that making it clearer to the user that the event arguments are empty would be better? Much thanks in advance, Mike

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  • Access Violation When Writing Dynamic 2D Array... Sometimes

    - by Shraptnel
    This program is meant to generate a dynamic array, however it gives an access violation error when writing when given certain dimensions. Eg: R = 6, C = 5 crashes, but then R = 5, C = 6 doesn't. In case your wondering, it isn't my homework to "fix" this broken program, this is the method we were taught in class. Also part of my assessment is to use this method, so vectors are out. Thanks in advance! #include <iostream> using namespace std; int main(){ const int R = 6; const int C = 5; char **d; d = new char *[R]; for(int i=0; i<C; ++i){ d[i] = new char[C]; } //initialise for(int i=0; i<R; ++i){ for(int j=0; j<C; ++j){ d[i][j] = 'd'; cout<<d[i][j]; } cout<<endl; } cout<<endl; system("pause"); return 0; }

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  • Why doesn't every class in the .Net framework have a corresponding interface?

    - by Thorsten Lorenz
    Since I started to develop in a test/behavior driven style, I appreciated the ability to mock out every dependency. Since mocking frameworks like Moq work best when told to mock an interface, I now implement an interface for almost every class I create b/c most likely I will have to mock it out in a test eventually. Well, and programming to an interface is good practice, anyways. At times, my classes take dependencies on .Net classes (e.g. FileSystemWatcher, DispatcherTimer). It would be great in that case to have an interface, so I could depend on an IDispatcherTimer instead, to be able to pass it a mock and simulate its behavior to see if my system under test reacts correctly. Unfortunately both of above mentioned classes do not implement such interfaces, so I have to resort to creating adapters, that do nothing else but inherit from the original class and conform to an interface, that I then can use. Here is such an adapter for the DispatcherTimer and the corresponding interface: using System; using System.Windows.Threading; public interface IDispatcherTimer { #region Events event EventHandler Tick; #endregion #region Properties Dispatcher Dispatcher { get; } TimeSpan Interval { get; set; } bool IsEnabled { get; set; } object Tag { get; set; } #endregion #region Public Methods void Start(); void Stop(); #endregion } /// <summary> /// Adapts the DispatcherTimer class to implement the <see cref="IDispatcherTimer"/> interface. /// </summary> public class DispatcherTimerAdapter : DispatcherTimer, IDispatcherTimer { } Although this is not the end of the world, I wonder, why the .Net developers didn't take the minute to make their classes implement these interfaces from the get go. It puzzles me especially since now there is a big push for good practices from inside Microsoft. Does anyone have any (maybe inside) information why this contradiction exists?

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  • Bind members of different classes

    - by 7vies
    In a C++ program I have two classes (structs) like struct A { int x; double y; // other members }; struct B { int x; double y2; // other members }; I'd like to somehow "bind" the corresponding members, e.g. A::x to B::x and A::y to B::y2. By "bind" I mean ability to obtain a reference to the bound variable, for example given a member of class A I could assign it to the value of the corresponding B member. Once I have such bind, I'd like to build a bind table or something similar which I could iterate over. This would allow, for example, copying the corresponding fields from A a; to B b; like CopyBound(a, b, bind_table);, but probably also doing some other things not limited to Copy interface. The problem with this bind_table is that I want static typing and the bind_table would have to contain different types in this case. For example, a table of pointers to class members would contain &A::x and &A::y, but they are of different type, so I cannot just put them say into an array. Any ideas how this can be conveniently implemented, having as much compile-time type checking as possible?

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  • .NET Process.Kill() in a safe way

    - by Orborde
    I'm controlling a creaky old FORTRAN simulator from a VB.NET GUI, using redirected I/O to communicate with the simulator executable. The GUI pops up a "status" window with a progress bar, estimated time, and a "STOP" button (Button_Stop). Now, I want the Button_Stop to terminate the simulator process immediately. The obvious way to do this is to call Kill() on the Child Process object. This gives an exception if it's done after the process has exited, but I can test whether the process is exited before trying to kill it, right? OK, so I do the following when the button is clicked: If Not Child.HasExited Then Child.Kill() Button_Stop.Enabled = False End If However, what if the process happens to exit between the test and the call to Kill()? In that case, I get an exception. The next thing to occur to me was that I can do Button_Stop.Enabled = False in the Process.Exited event handler, and thus prevent the Child.Kill() call in the Button_Stop.Clicked handler. But since the Process.Exited handler is called on a different thread, that still leaves the following possible interleaving: Child process exits. Process.Exited fires, calls Invoke to schedule the Button_Stop.Enabled = False User clicks on Button_Stop, triggering Child.Kill() Button_Stop.Enabled = False actually happens. An exception would then be thrown on step 3. How do I kill the process without any race conditions? Am I thinking about this entirely wrong?

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  • Java equivalent to VS solution file

    - by Chris
    I'm a C# guy trying to learn Java. I understand the syntax and the basic architecture of the Java platform, and have no problem doing smaller projects myself, but I'd really like to be able to download some open source projects to learn from the work of others. However, I'm running into a stumbling block that I can't seem to find any information on. When I download an open source .NET project, I can open the .sln file with visual studio and everything just loads. Sure, there's occasionally a missing reference or something, but there's really very little configuration required to get things going. I'm not sensing the same ease of use with Java. I'm using eclipse at the moment, and it feels like for every project I have to create a brand new Eclipse project using "create from existing source", and almost nothing compiles properly without significant reconfiguration. In the case of web projects, it's even worse, because Eclipse doesn't appear to support creating a web project from existing source. I have to create a standard Java project from source, then then apparently modify the project file to include the bindings for the web toolkit stuff to work properly. Assuming I want to be able to contribute to a project later on, I shouldn't have to be making such drastic changes to the file structure to get my IDE to a workable state. What am I missing?

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  • Regex: markdown-style link matching

    - by The.Anti.9
    I want to parse markdown style links, but I'm having some trouble matching the reference style ones. Like this one: [id]: http://example.com/ "Optional Title Here" My regex gets the id and the url, but not the title. Heres what I have: /\[([a-zA-Z0-9_-]+)\]: (\S+)\s?("".*?"")?/ I go through and add the references to a hashtable. the id as the key and the value is an instance of a class I made called LinkReference that just contains the url and the title. In case the problem is not my regex, and my code adding the matches to the hash table, Heres my code for that too: Regex rx = new Regex(@"\[([a-zA-Z0-9_-]+)\]: (\S+)\s?("".*?"")?"); MatchCollection matches = rx.Matches(InputText); foreach (Match match in matches) { GroupCollection groups = match.Groups; string title = null; try { title = groups[3].Value; } catch (Exception) { // keep title null } LinkReferences.Add(groups[1].Value, new LinkReference(groups[2].Value, title)); }

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  • "Programming In Haskell" error in sat function

    - by Matt Ellen
    I'm in chapter 8 of Graham Hutton's Programming in Haskell and I'm copying the code and testing it in GHC. See the slides here: http://www.cis.syr.edu/~sueo/cis352/chapter8.pdf in particular slide 15 The relevant code I've copied so far is: type Parser a = String -> [(a, String)] pih_return :: a -> Parser a pih_return v = \inp -> [(v, inp)] failure :: Parser a failure = \inp -> [] item :: Parser Char item = \inp -> case inp of [] -> [] (x:xs) -> [(x,xs)] parse :: Parser a -> String -> [(a, String)] parse p inp = p inp sat :: (Char -> Bool) -> Parser Char sat p = do x <- item if p x then pih_return x else failure I have changed the name of the return function from the book to pih_return so that it doesn't clash with the Prelude return function. The errors are in the last function sat. I have copied this directly from the book. As you can probably see p is a function from Char to Bool (e.g. isDigit) and x is of type [(Char, String)], so that's the first error. Then pih_return takes a value v and returns [(v, inp)] where inp is a String. This causes an error in sat because the v being passed is x which is not a Char. I have come up with this solution, by explicitly including inp into sat sat :: (Char -> Bool) -> Parser Char sat p inp = do x <- item inp if p (fst x) then pih_return (fst x) inp else failure inp Is this the best way to solve the issue?

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  • Variable-width inline underline effects in CSS

    - by sidereal
    I need to simulate the look of a typical paper form in CSS. It consists of a two-column table of fields. Each field consists of a field name (of variable width) followed by an underline that continues to the end of the column. The field might be populated, in which case there is some text centered above the line, or it may be blank. If that isn't clear, he's a rough idea in manky ASCII art: Name: _______Foo_______ Age: _____17______ Location: __Melbourne__ Handedness: _Left_ (except that the underline would continue under any text) To implement the underline without text, I assume I should use a border-bottom rather than a text-decoration: underline. Additionally, I need the bordered element to take up the full available space. Both of those argue for a block-level element. However, I can't find any way to get the block level element (either a div, an li, or a span set to display: block or inline-block) to remain on the same line as the label. As soon as I give it a width: 100%, it newlines. I've tried various combinations of floats, and I'm not inclined to do anything ridiculous with absolute positioning. Any recommendations?

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  • Iteration speed of int vs long

    - by jqno
    I have the following two programs: long startTime = System.currentTimeMillis(); for (int i = 0; i < N; i++); long endTime = System.currentTimeMillis(); System.out.println("Elapsed time: " + (endTime - startTime) + " msecs"); and long startTime = System.currentTimeMillis(); for (long i = 0; i < N; i++); long endTime = System.currentTimeMillis(); System.out.println("Elapsed time: " + (endTime - startTime) + " msecs"); Note: the only difference is the type of the loop variable (int and long). When I run this, the first program consistently prints between 0 and 16 msecs, regardless of the value of N. The second takes a lot longer. For N == Integer.MAX_VALUE, it runs in about 1800 msecs on my machine. The run time appears to be more or less linear in N. So why is this? I suppose the JIT-compiler optimizes the int loop to death. And for good reason, because obviously it doesn't do anything. But why doesn't it do so for the long loop as well? A colleague thought we might be measuring the JIT compiler doing its work in the long loop, but since the run time seems to be linear in N, this probably isn't the case.

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  • Advice on optimzing speed for a Stored Procedure that uses Views

    - by Belliez
    Based on a previous question and with a lot of help from Damir Sudarevic (thanks) I have the following sql code which works great but is very slow. Can anyone suggest how I can speed this up and optimise for speed. I am now using SQL Server Express 2008 (not 2005 as per my original question). What this code does is retrieves parameters and their associated values from several tables and rotates the table in a form that can be easily compared. Its great for one of two rows of data but now I am testing with 100 rows and to run GetJobParameters takes over 7 minutes to complete? Any advice is gratefully accepted, thank you in advanced. /*********************************************************************************************** ** CREATE A VIEW (VIRTUAL TABLE) TO ALLOW EASIER RETREIVAL OF PARMETERS ************************************************************************************************/ CREATE VIEW dbo.vParameters AS SELECT m.MachineID AS [Machine ID] ,j.JobID AS [Job ID] ,p.ParamID AS [Param ID] ,t.ParamTypeID AS [Param Type ID] ,m.Name AS [Machine Name] ,j.Name AS [Job Name] ,t.Name AS [Param Type Name] ,t.JobDataType AS [Job DataType] ,x.Value AS [Measurement Value] ,x.Unit AS [Unit] ,y.Value AS [JobDataType] FROM dbo.Machines AS m JOIN dbo.JobFiles AS j ON j.MachineID = m.MachineID JOIN dbo.JobParams AS p ON p.JobFileID = j.JobID JOIN dbo.JobParamType AS t ON t.ParamTypeID = p.ParamTypeID LEFT JOIN dbo.JobMeasurement AS x ON x.ParamID = p.ParamID LEFT JOIN dbo.JobTrait AS y ON y.ParamID = p.ParamID GO -- Step 2 CREATE VIEW dbo.vJobValues AS SELECT [Job Name] ,[Param Type Name] ,COALESCE(cast([Measurement Value] AS varchar(50)), [JobDataType]) AS [Val] FROM dbo.vParameters GO /*********************************************************************************************** ** GET JOB PARMETERS FROM THE VIEW JUST CREATED ************************************************************************************************/ CREATE PROCEDURE GetJobParameters AS -- Step 3 DECLARE @Params TABLE ( id int IDENTITY (1,1) ,ParamName varchar(50) ); INSERT INTO @Params (ParamName) SELECT DISTINCT [Name] FROM dbo.JobParamType -- Step 4 DECLARE @qw TABLE( id int IDENTITY (1,1) , txt nchar(300) ) INSERT INTO @qw (txt) SELECT 'SELECT' UNION SELECT '[Job Name]' ; INSERT INTO @qw (txt) SELECT ',MAX(CASE [Param Type Name] WHEN ''' + ParamName + ''' THEN Val ELSE NULL END) AS [' + ParamName + ']' FROM @Params ORDER BY id; INSERT INTO @qw (txt) SELECT 'FROM dbo.vJobValues' UNION SELECT 'GROUP BY [Job Name]' UNION SELECT 'ORDER BY [Job Name]'; -- Step 5 --SELECT txt FROM @qw DECLARE @sql_output VARCHAR (MAX) SET @sql_output = '' -- NULL + '' = NULL, so we need to have a seed SELECT @sql_output = -- string to avoid losing the first line. COALESCE (@sql_output + txt + char (10), '') FROM @qw EXEC (@sql_output) GO

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  • In C# should I reuse a function / property parameter to compute temp result or create a temporary v

    - by Hamish Grubijan
    The example below may not be problematic as is, but it should be enough to illustrate a point. Imagine that there is a lot more work than trimming going on. public string Thingy { set { // I guess we can throw a null reference exception here on null. value = value.Trim(); // Well, imagine that there is so much processing to do this.thingy = value; // That this.thingy = value.Trim() would not fit on one line ... So, if the assignment has to take two lines, then I either have to abusereuse the parameter, or create a temporary variable. I am not a big fan of temporary variables. On the other hand, I am not a fan of convoluted code. I did not include an example where a function is involved, but I am sure you can imagine it. One concern I have is if a function accepted a string and the parameter was "abused", and then someone changed the signature to ref in both places - this ought to mess things up, but ... who would knowingly make such a change if it already worked without a ref? Seems like it is their responsibility in this case. If I mess with the value of value, am I doing something non-trivial under the hood? If you think that both approaches are acceptable, then which do you prefer and why? Thanks.

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