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  • Are bit operations quick?

    - by flashnik
    I'm dealing with a problem which needs to work with a lot of data. Currently its' values are represented as unsigned int. I know that real values do not exceed some limit, say 1000. That means that I can use unsigned short to store it. One profit is that it'll use less space. Do I have to pay for it by loosing in performance? Another assumption. I decided to store data as short but all calling functions use int, so I need to convert between these datatypes when storing/extracting values. Wiil the performance lost be dramatic? Third assumption. Due to great wish to econom memory I decided to use not short but just 10 bits packed into array of unsigned int. What will happen in this case comparing with previous ones?

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  • String operations

    - by NEO
    I am trying to find the most repeated word in a string. My code is as follows: public class Word { private String toWord; private int Count; public Word(int count, String word){ toWord = word; Count = count; } public static void main(String args[]){ String str="my name is neo and my other name is also neo because I am neo"; String []str1=str.split(" "); Word w1=new Word(0,str1[0]); LinkedList<Word> list = new LinkedList<Word>(); list.add(w1); ListIterator itr = list.listIterator(); for(int i=1;i<str1.length;i++){ while(itr.hasNext()){ if(str1[i].equalsTO(????)); else list.add(new Word(0,str1[i])); } How do I compare the string from string array str1 to the string stored in the linked list and then how do i increase the respective count. I will then print the string with the highest count, I dont know how to do that either.

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  • How to block the UI during asynchronous operations in WPF

    - by mcintyre321
    We have a WPF app (actually a VSTO WPF app). On certain controls there are multiple elements which, when clicked, load data from a web service and update the UI. Right now, we carry out these web requests synchronously, blocking the UI thread until the response comes back. This prevents the user clicking around the app while the data is loading, potentially putting it into an invalid state to handle the data when it is returned. Of course the app becomes unresponsive if the request takes a long time. Ideally, we'd like to have the cancel button active during this time, but nothing else. Is there a clever way of doing this, or will we have to switch the requests to execute asynchronously using backgroundworker and write something that disables all the controls apart from the cancel button while a request is in progress?

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  • Using SQL dB column as a lock for concurrent operations in Entity Framework

    - by Sid
    We have a long running user operation that is handled by a pool of worker processes. Data input and output is from Azure SQL. The master Azure SQL table structure columns are approximated to [UserId, col1, col2, ... , col N, beingProcessed, lastTimeProcessed ] beingProcessed is boolean and lastTimeProcessed is DateTime. The logic in every worker role is: public void WorkerRoleMain() { while(true) { try { dbContext db = new dbContext(); // Read foreach (UserProfile user in db.UserProfile .Where(u => DateTime.UtcNow.Subtract(u.lastTimeProcessed) > TimeSpan.FromHours(24) & u.beingProcessed == false)) { user.beingProcessed = true; // Modify db.SaveChanges(); // Write // Do some long drawn processing here ... ... ... user.lastTimeProcessed = DateTime.UtcNow; user.beingProcessed = false; db.SaveChanges(); } } catch(Exception ex) { LogException(ex); Sleep(TimeSpan.FromMinutes(5)); } } // while () } With multiple workers processing as above (each with their own Entity Framework layer), in essence beingProcessed is being used a lock for MutEx purposes Question: How can I deal with concurrency issues on the beingProcessed "lock" itself based on the above load? I think read-modify-write operation on the beingProcessed needs to be atomic but I'm open to other strategies. Open to other code refinements too.

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  • identity specification gap after several operations

    - by Babak.Abad
    I'm using identity specification for a table of sql server 2012. Let we have two Insert and then two Delete operation. After these operation primary key should start from 1, but it will start from 3. I'm worry about this problem causing no place for inserting new item after long time. Does "Sql-server 2012" fill these gaps by itself? If it is possible, please refer me a documentation ( for example from microsoft)

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  • Accepting drag operations in an NSCollectionView subclass

    - by andyvn22
    I've subclassed NSCollectionView and I'm trying to receive dragged files from the Finder. I'm receiving draggingEntered: and returning an appropriate value, but I'm never receiving prepareForDragOperation: (nor any of the methods after that in the process). Is there something obvious I'm missing here? Code: - (void)awakeFromNib { [self registerForDraggedTypes:[NSArray arrayWithObjects:NSFilenamesPboardType, nil]]; } - (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender { NSLog(@"entered"); //Happens NSPasteboard *pboard; NSDragOperation sourceDragMask; sourceDragMask = [sender draggingSourceOperationMask]; pboard = [sender draggingPasteboard]; if ([[pboard types] containsObject:NSFilenamesPboardType]) { NSLog(@"copy"); //Happens return NSDragOperationCopy; } return NSDragOperationNone; } - (BOOL)prepareForDragOperation:(id <NSDraggingInfo>)sender { NSLog(@"prepare"); //Never happens return YES; }

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  • Creating standalone, console (shell) for domain-specific operations

    - by mr.b
    Say that I have a system service, and I want to offer a low-level maintenance access to it. For that purpose, I'd like to create a standalone, console application that somehow connects to server process and lets user type in commands, allow it to use auto-completion and auto-suggestion on single/double TAB press (just like linux bash shell, mysql cli, cmd.exe, and countless others), allow command line editing capabilities (history, cursor keys to move around text..), etc. Now, it's not that much of a problem to create something like that by rolling my own from scratch, handling user input, scanning pressed keys, and doing correct actions. But, why reinvent the wheel? Is there some library/framework that helps with this kind of problems, just like readline library that offers improved command-line editing capabilities under linux? Of course, this new "shell" would respond only to valid, domain-specific commands, and would suggest valid arguments, options, switches... Any ideas? Thanks!

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  • Core Data: Multiple conditions inside relational aggregate operations

    - by Uzaak
    I have an SQLite table used by Core Data with the following elements: Name: John LastName: Foobar Age: 23 Name: Bob LastName: Baz Age: 37 Name: Peter LastName: Fooqux Age: 32 Name: John LastName: Bar Age: 29 Those are all in a to-many relationship from another object "Company". I need to query the database and retrieve all Company objects with employees called "John" but whose last name does NOT contain "Foo". I did go as far as to make the following predicate: [NSPredicate predicateWithFormat:@"ANY employee.name = 'John'"]; How do I get to filter only by companies whose Johns don't have "Foo" in their last names?

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  • Use date operations on a computed field filter in a view

    - by stephenhay
    I'd like to expose a filter in Views based on a Computed Field. This field should utilize the date operation "less than". Apparently, a date type is not available to computed field (varchar is). However, using varchar results in views treating the field as a string rather than as a date, without the operation I'm looking for. So I tried using a timestamp instead of a date, which allowed me to use an integer data type. The exposed view gives me a "less than" operation, but as it's still not a date, the user must type in a timestamp. Not handy. So I'm thinking the best way to do this is to create a new (hidden) CCK field which is a date field, and set the value of this field to the value of the Computed Field. I can then use the new CCK field for my exposed filter. But I'm not getting anywhere with this, as I'm unsure how to set another CCK field with a Computed Field. To return the value to the computed field itself, I'm using the standard: $node_field[0]['value'] = $newestdate; I would like to set the value of the new CCK field to $newestdate as well. Can anyone help?

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  • segmentation fault in file operations in c

    - by mekasperasky
    #include<stdio.h> /* this is a lexer which recognizes constants , variables ,symbols, identifiers , functions , comments and also header files . It stores the lexemes in 3 different files . One file contains all the headers and the comments . Another file will contain all the variables , another will contain all the symbols. */ int main() { int i; char a,b[20],c; FILE *fp1; fp1=fopen("source.txt","r"); //the source file is opened in read only mode which will passed through the lexer //now lets remove all the white spaces and store the rest of the words in a file if(fp1==NULL) { perror("failed to open source.txt"); //return EXIT_FAILURE; } i=0; while(1) { a=fgetc(fp1); if(a !="") { b[i]=a; } else { fprintf(fp1, "%.20s\n", b); i=0; continue; } i=i+1; /*Switch(a) { case EOF :return eof; case '+':sym=sym+1; case '-':sym=sym+1; case '*':sym=sym+1; case '/':sym=sym+1; case '%':sym=sym+1; case ' */ } return 0; } how does this code end up in segmentation fault?

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  • Servlets, long operations

    - by asrijaal
    Hi there, I'm refactoring a big piece of code atm where a long taking operation is executed in a servlet. Now sometimes I don't get a response after the operation has finished. (It has finished because it is printed into the logs) What I wish to achieve would some "fire and forget" behavior by the servlet. I would pass my params to the action and the servlet would immediately return a status (something like: the operation has started, check your logs for further info) Is this possible with servlet 2.5 spec? I think I could get such a behavior with JMS maybe any other solutions out there?

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  • Force redraw before long running operations

    - by Joshua
    When you have a button, and do something like: Private Function Button_OnClick Button.Enabled = False [LONG OPERATION] End Function Then the button will not be grayed, because the long operation prevents the UI thread from repainting the control. I know the right design is to start a background thread / dispatcher, but sometimes that's too much hassle for a simple operation. So how do I force the button to redraw in disabled state? I tried .UpdateLayout() on the Button, but it didn't have any effects. I also tried System.Windows.Forms.DoEvents() which normally works when using WinForms, but it also had no effect.

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  • basic operations for modifying a source document with XSLT

    - by SpliFF
    All the tutorials and examples I've found of XSLT processing seem to assume your destination will be a significantly different format/structure to your source and that you know the structure of the source in advance. I'm struggling with finding out how to perform simple "in-place" modifications to a HTML document without knowing anything else about its existing structure. Could somebody show me a clear example that, given an arbitrary unknown HTML source will: 1.) delete the classname 'foo' from all divs 2.) delete a node if its empty (ie <p></p>) 3.) delete a <p> node if its first child is <br> 4.) add newattr="newvalue" to all H1 5.) replace 'heading' in text nodes with 'title' 6.) wrap all <u> tags in <b> tags (ie, <u>foo</u> -> <b><u>foo</u></b>) 7.) output the transformed document without changing anything else The above examples are the primary types of transform I wish to accomplish. Understanding how to do the above will go a long way towards helping me build more complex transforms. To help clarify/test the examples here is a sample source and output, however I must reiterate that I want to work with arbitrary samples without rewriting the XSLT for each source: <!doctype html> <html> <body> <h1>heading</h1> <p></p> <p><br>line</p> <div class="foo bar"><u>baz</u></div> <p>untouched</p> </body> </html> output: <!doctype html> <html> <body> <h1 newattr="newvalue">title</h1> <div class="bar"><b><u>baz</u></b></div> <p>untouched</p> </body> </html>

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  • Data on the Frequency of Edit Operations Required to Correct a Misspelt Word

    - by gvkv
    Does anybody know of any data that relates to the frequency of the types of mistakes the people make when they misspell a word? I'm not referring to words themselves, but tje errors that are made by the typist. For example, I personally make transposition errors the most followed by deletion errors (that is, not including a letter I should), substitution errors and lastly, insertion errors. However, it would not surprise me to find out that typing a wrong letter (a substitution error, e.g., xat instead of cat) is more frequent than not including a letter. My purpose is to be able to make best guesses at correcting a word when I only have the original user's input. The idea being that if one type of error is more frequent than others, then it's more likely that correcting a word via that type of operation is correct. I don't object to using a database of commonly misspelt words but I prefer an algorithmic solution to depending on a corpus--especially if it might be faster.

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  • Operations on bytes in C#

    - by Hooch
    Hello. I'm writing application to control LEDS on LPT. I have everything working except this. This is one small function. I have sth like that: I want to build function that will take two argument and return one number: In actual code those binary numers will be in hex. I put them there like that so that it's easier for you to visualize it. Example1: arg1 = 1100 1100 arg2 = 1001 0001 retu = 0100 1100 Example2: arg1 = 1111 1111 arg2 = 0001 0010 retu = 1110 1101 Example3: arg1 = 1111 0000 arg2 = 0010 0010 retu = 1101 0000 I have no idea how this function should look like. I want it to be as fast as possible. I'll call this function 200 times per second.

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  • Multiple operations depending on the type of the object passed

    - by mixm
    Assuming I create a method which is passed an object and that method would perform an action depending on the object passed. How should I identify the object? I thought of using the class name to identify the object, but that may be impractical since I could easily change the class name of objects, and generate headaches during future development. Am I right? edit: for example, i have objects ball and bomb. if i have another object called wall, and the wall has the method to resolve collisions with the wall (e.g. the coordinates of the colliding ball and bomb) but have different logic depending on the colliding object (i.e. ball and bomb)

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  • Workflow Foundation: Asynchronous operations (lengthy network I/O)

    - by StormianRootSolver
    I have to create an application that will be started a few times per day (it's non - interactive). To operate, it needs LARGE amounts of data from the Internet (megabytes) via a rather slow connection, so the WCF service calls take quite some time. At the same time, it needs to perform local calculations and has a sophisticated initialization process. So, what I want to do is to create a workflow that asynchronously fetches the data (takes a few minutes) while already initializing / calculating locally. Is there a way to accomplish this?

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  • String split operations in C# .

    - by Indigo Praveen
    Hi All, I have a string say string s ="C:\\Data" , I have an array which contains some strings containg "C:\Data" in the beginning i.e. string[] arr = new {"C:\\Data\abc.xml","C:\\Data\Test\hello.cs"};. I have to remove the string "C:\Data" from each entry and have to combine it with another string say string fixed = "D:\\Data". What is the best way to do it, please help as I am a new programmer in C#.

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  • Invalid Cross-Thread Operations from BackgroundWorker2_RunWorkerCompleted in C#

    - by Jim Fell
    Hello. I'm getting an error that does not make sense. Cross-thread operation not valid: Control 'buttonOpenFile' accessed from a thread other than the thread it was created on. In my application, the UI thread fires off backgroundWorker1, which when almost complete fires off backgroundWorker2 and waits for it to complete. backgroundWorker1 waits for backgroundWorker2 to complete, before it completes. AutoResetEvent variables are used to flag when each of the workers complete. In backgroundWorker2_RunWorkerComplete a function is called that resets the form controls. It is in this ResetFormControls() function where the exception is thrown. I thought it was safe to modify form controls in the RunWorkerCompleted function. Both background workers are instantiated from the UI thread. Here is a greatly summarized version of what I am doing: AutoResetEvent evtProgrammingComplete_c = new AutoResetEvent(false); AutoResetEvent evtResetComplete_c = new AutoResetEvent(false); private void ResetFormControls() { toolStripProgressBar1.Enabled = false; toolStripProgressBar1.RightToLeftLayout = false; toolStripProgressBar1.Value = 0; buttonInit.Enabled = true; buttonOpenFile.Enabled = true; // Error occurs here. buttonProgram.Enabled = true; buttonAbort.Enabled = false; buttonReset.Enabled = true; checkBoxPeripheryModule.Enabled = true; checkBoxVerbose.Enabled = true; comboBoxComPort.Enabled = true; groupBoxToolSettings.Enabled = true; groupBoxNodeSettings.Enabled = true; } private void buttonProgram_Click(object sender, EventArgs e) { while (backgroundWorkerProgram.IsBusy) backgroundWorkerProgram.CancelAsync(); backgroundWorkerProgram.RunWorkerAsync(); } private void backgroundWorkerProgram_DoWork(object sender, DoWorkEventArgs e) { // Does a bunch of stuff... if (tProgramStat_c == eProgramStat_t.DONE) { tProgramStat_c = eProgramStat_t.RESETTING; while (backgroundWorkerReset.IsBusy) backgroundWorkerReset.CancelAsync(); backgroundWorkerReset.RunWorkerAsync(); evtResetComplete_c.WaitOne(LONG_ACK_WAIT * 2); if (tResetStat_c == eResetStat_t.COMPLETED) tProgramStat_c = eProgramStat_t.DONE; } } private void backgroundWorkerProgram_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { // Updates form to report complete. No problems here. evtProgrammingComplete_c.Set(); backgroundWorkerProgram.Dispose(); } private void backgroundWorkerReset_DoWork(object sender, DoWorkEventArgs e) { // Does a bunch of stuff... if (tResetStat_c == eResetStat_t.COMPLETED) if (tProgramStat_c == eProgramStat_t.RESETTING) evtProgrammingComplete_c.WaitOne(); } private void backgroundWorkerReset_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { CloseAllComms(); ResetFormControls(); evtResetComplete_c.Set(); backgroundWorkerReset.Dispose(); } Any thoughts or suggestions you may have would be appreciated. I am using Microsoft Visual C# 2008 Express Edition. Thanks.

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  • java multiple operations depending on the type of the object passed

    - by mixm
    assuming i create a method which is passed an object, and that method would perform an action depending on the object passed. how should i identify the object? i thought of using the class name to identify the object, but may be impractical since i could easily change the class name of objects, and generate headaches during future development. am i right?

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  • Bitfield mask/operations with optional items

    - by user1560249
    I'm trying to find a way to handle several bitfield cases that include optional, required, and not allowed positions. yy?nnn?y 11000001 ?yyy?nnn 01110000 nn?yyy?n 00011100 ?nnn?yyy 00000111 In these four cases, the ? indicates that the bit can be either 1 or 0 while y indicates a 1 is required and n indicates that a 0 is required. The bits to the left/right of the required bits can be anything and the remaining bits must be 0. Is there a masking method I can use to test if an input bit set satisfies one of these cases?

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