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  • Any sense to set obj = null(Nothing) in Dispose()?

    - by serhio
    Is there any sense to set custom object to null(Nothing in VB.NET) in the Dispose() method? Could this prevent memory leaks or it's useless?! Let's consider two examples: public class Foo : IDisposable { private Bar bar; // standard custom .NET object public Foo(Bar bar) { this.bar = bar; } public void Dispose() { bar = null; // any sense? } } public class Foo : RichTextBox { // this could be also: GDI+, TCP socket, SQl Connection, other "heavy" object private Bitmap backImage; public Foo(Bitmap backImage) { this.backImage = backImage; } protected override void Dispose(bool disposing) { if (disposing) { backImage = null; // any sense? } } }

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  • How to handle ordering of @Rule's when they are dependant on eachother

    - by Lennart Schedin
    I use embedded servers that run inside Junit test cases. Sometimes these servers require a working directory (for example the Apache Directory server). The new @Rule in Junit 4.7 can handle these cases. The TemporaryFolder-Rule can create a temporary directory. A custom ExternalResource-Rule can be created for server. But how do I handle if I want to pass the result from one rule into another: import static org.junit.Assert.assertEquals; import java.io.*; import org.junit.*; import org.junit.rules.*; public class FolderRuleOrderingTest { @Rule public TemporaryFolder folder = new TemporaryFolder(); @Rule public MyNumberServer server = new MyNumberServer(folder); @Test public void testMyNumberServer() throws IOException { server.storeNumber(10); assertEquals(10, server.getNumber()); } /** Simple server that can store one number */ private static class MyNumberServer extends ExternalResource { private TemporaryFolder folder; /** The actual datafile where the number are stored */ private File dataFile; public MyNumberServer(TemporaryFolder folder) { this.folder = folder; } @Override protected void before() throws Throwable { if (folder.getRoot() == null) { throw new RuntimeException("TemporaryFolder not properly initialized"); } //All server data are stored to a working folder File workingFolder = folder.newFolder("my-work-folder"); dataFile = new File(workingFolder, "datafile"); } public void storeNumber(int number) throws IOException { dataFile.createNewFile(); DataOutputStream out = new DataOutputStream(new FileOutputStream(dataFile)); out.writeInt(number); } public int getNumber() throws IOException { DataInputStream in = new DataInputStream(new FileInputStream(dataFile)); return in.readInt(); } } } In this code the folder is sent as a parameter into the server so that the server can create a working directory to store data. However this does not work because Junit processes the rules in reverse order as they are defined in the file. The TemporaryFolder Rule will not be executed before the server Rule. Thus the root-folder in TempraryFolder will be null, resulting that any files are created relative to the current working directory. If I reverse the order of the attributes in my class I get a compile error because I cannot reference a variable before it is defined. I'm using Junit 4.8.1 (because the ordering of rules was fixed a bit from the 4.7 release)

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  • EXC_BAD_ACCESS at UITableView on IOS

    - by Suprie
    Hi all, When scrolling through table, my application crash and console said it was EXC_BAD_ACCESS. I've look everywhere, and people suggest me to use NSZombieEnabled on my executables environment variables. I've set NSZombieEnabled, NSDebugEnabled, MallocStackLogging and MallocStackLoggingNoCompact to YES on my executables. But apparently i still can't figure out which part of my program that cause EXC_BAD_ACCESS. This is what my console said [Session started at 2010-12-21 21:11:21 +0700.] GNU gdb 6.3.50-20050815 (Apple version gdb-1510) (Wed Sep 22 02:45:02 UTC 2010) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "x86_64-apple-darwin".sharedlibrary apply-load-rules all Attaching to process 9335. TwitterSearch(9335) malloc: recording malloc stacks to disk using standard recorder TwitterSearch(9335) malloc: process 9300 no longer exists, stack logs deleted from /tmp/stack-logs.9300.TwitterSearch.suirlR.index TwitterSearch(9335) malloc: stack logs being written into /tmp/stack- logs.9335.TwitterSearch.tQJAXk.index 2010-12-21 21:11:25.446 TwitterSearch[9335:207] View Did Load Program received signal: “EXC_BAD_ACCESS”. And this is when i tried to type backtrace on gdb : Program received signal: “EXC_BAD_ACCESS”. (gdb) backtrace #0 0x00f20a67 in objc_msgSend () #1 0x0565cd80 in ?? () #2 0x0033b7fa in -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:withIndexPath:] () #3 0x0033177f in -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:] () #4 0x00346450 in -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow:] () #5 0x0033e538 in -[UITableView layoutSubviews] () #6 0x01ffc451 in -[CALayer layoutSublayers] () #7 0x01ffc17c in CALayerLayoutIfNeeded () #8 0x01ff537c in CA::Context::commit_transaction () #9 0x01ff50d0 in CA::Transaction::commit () #10 0x020257d5 in CA::Transaction::observer_callback () #11 0x00d9ffbb in __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ () #12 0x00d350e7 in __CFRunLoopDoObservers () #13 0x00cfdbd7 in __CFRunLoopRun () #14 0x00cfd240 in CFRunLoopRunSpecific () #15 0x00cfd161 in CFRunLoopRunInMode () #16 0x01a73268 in GSEventRunModal () #17 0x01a7332d in GSEventRun () #18 0x002d642e in UIApplicationMain () #19 0x00001d4e in main (argc=1, argv=0xbfffee34) at /Users/suprie/Documents/Projects/Self/cocoa/TwitterSearch/main.m:14 I really appreciate for any clue to help me debug my application. EDIT this is the Header file of table #import <UIKit/UIKit.h> @interface TwitterTableViewController : UITableViewController { NSMutableArray *twitters; } @property(nonatomic,retain) NSMutableArray *twitters; @end and the implementation file #import "TwitterTableViewController.h" @implementation TwitterTableViewController @synthesize twitters; #pragma mark - #pragma mark Table view data source - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { // Return the number of sections. return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { // Return the number of rows in the section. return [twitters count]; } - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath { return 90.0f; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { const NSInteger TAG_IMAGE_VIEW = 1001; const NSInteger TAG_TWEET_VIEW = 1002; const NSInteger TAG_FROM_VIEW = 1003; static NSString *CellIdentifier = @"Cell"; UIImageView *imageView; UILabel *tweet; UILabel *from; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; // Image imageView = [[[[UIImageView alloc] initWithFrame:CGRectMake(5.0f, 5.0f, 60.0f, 60.0f)] autorelease] retain]; [cell.contentView addSubview:imageView]; imageView.tag = TAG_IMAGE_VIEW; // Tweet tweet = [[[UILabel alloc] initWithFrame:CGRectMake(105.0f, 5.0f, 200.0f, 50.0f)] autorelease]; [cell.contentView addSubview:tweet]; tweet.tag = TAG_TWEET_VIEW; tweet.numberOfLines = 2; tweet.font = [UIFont fontWithName:@"Helvetica" size:12]; tweet.textColor = [UIColor blackColor]; tweet.backgroundColor = [UIColor clearColor]; // From from = [[[UILabel alloc] initWithFrame:CGRectMake(105.0f, 55.0, 200.0f, 35.0f)] autorelease]; [cell.contentView addSubview:from]; from.tag = TAG_FROM_VIEW; from.numberOfLines = 1; from.font = [UIFont fontWithName:@"Helvetica" size:10]; from.textColor = [UIColor blackColor]; from.backgroundColor = [UIColor clearColor]; } // Configure the cell... NSMutableDictionary *twitter = [twitters objectAtIndex:(NSInteger) indexPath.row]; // cell.text = [twitter objectForKey:@"text"]; tweet.text = (NSString *) [twitter objectForKey:@"text"]; tweet.hidden = NO; from.text = (NSString *) [twitter objectForKey:@"from_user"]; from.hidden = NO; NSString *avatar_url = (NSString *)[twitter objectForKey:@"profile_image_url"]; NSData * imageData = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: avatar_url]]; imageView.image = [UIImage imageWithData: imageData]; imageView.hidden = NO; return cell; } #pragma mark - #pragma mark Table view delegate - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { NSMutableDictionary *twitter = [twitters objectAtIndex:(NSInteger)indexPath.row]; NSLog(@"Twit ini kepilih :%@", [twitter objectForKey:@"text"]); } #pragma mark - #pragma mark Memory management - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; } - (void)viewDidUnload { } - (void)dealloc { [super dealloc]; } @end

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  • Stringbuilder problem creating dynamic links

    - by wali
    Hi all, I'm having an issue creating a link like "<a href="javascript:window.open('www.microsoft.com');">Visit Microsoft</a> using stringbuilder. I am adding html to a panel dynamically and I am trying to create a popup link. The problem is that for some reason the link gets "mixed up". For example: Dim s As String sb.Append("<A HREF='javascript:void(0)' onclick='window.open(") sb.Append("'") sb.Append("Match.aspx?MatchID=") sb.Append(mt.MatchID) sb.Append("&batchid=") sb.Append(mb.batchID) sb.Append("')>") sb.Append("Match</A>") gives an output of : <a match.aspx?matchid="28840&amp;batchid=26596')" onclick="window.open(" href="javascript:void(0)">Match</a> I have no clue what I'm doing wrong, it even does this kind of crap for a regular string! Please help!

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  • Problem with tcp server when converting to service

    - by djerry
    Hello lads, I'm working on monitoring some object (cdr-packets). I'm setting up a tcp-server and am listening on port 50043 for the packages. The program as a console application is working just fine, my server is working like it should and i'm receiving the packets. When i try to use it as a service, i cannot seem to get a client connected to my server. Is there something i need to change to deploy this as a service? Code below is from my application: this is my service class where i start protected override void OnStart(string[] args) { server = new TcpServer(); server.StartServer(); } this is the constructor of TcpServer public TcpServer() { try { _server = new TcpListener(IPAddress.Any, 50043); } catch (Exception) { _server = null; } } this is the method i call after initialising the class public void StartServer() { if (_server != null) { // Create a ArrayList for storing SocketListeners before starting the server. _socketListenersList = new ArrayList(); // Start the Server and start the thread to listen client requests. _server.Start(); _serverThread = new Thread(new ThreadStart(ServerThreadStart)); _serverThread.Start(); // Create a low priority thread that checks and deletes client // SocktConnection objcts that are marked for deletion. _purgingThread = new Thread(new ThreadStart(PurgingThreadStart)); _purgingThread.Priority = ThreadPriority.Lowest; _purgingThread.Start(); } } this is the thread that keep checking if any client tries to connect private void ServerThreadStart() { // Client Socket variable; Socket clientSocket = null; TcpSocketListener socketListener = null; while (!_stopServer) { try { // Wait for any client requests and if there is any request from any //client accept it (Wait indefinitely). clientSocket = _server.AcceptSocket(); // Create a SocketListener object for the client. socketListener = new TcpSocketListener(clientSocket); // Add the socket listener to an array list in a thread safe fashon. lock (_socketListenersList) { _socketListenersList.Add(socketListener); } // Start a communicating with the client in a different thread. socketListener.StartSocketListener(); } catch (SocketException se) { _stopServer = true; } } } when for the first time a packet waits to be read, and i get to "clientSocket = _server.AcceptSocket();", it throws an exception (service, not very good debugable) Does anyone recognize this problem or can help me? Thanks in advance

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  • Storyboard as timer in WPF

    - by Adrian
    Hi, I'm trying to do smooth animation in procedural code. For this (in Silverlight at least), it's recommended to use the Storyboard timer rather than a DispatcherTimer. So I use something like this: Storyboard _LoopTimer = new Storyboard(); public void StartAnimation() { _LoopTimer.Duration = TimeSpan.FromMilliseconds(0); _LoopTimer.Completed += new EventHandler(MainLoop); _LoopTimer.Begin(); } void MainLoop(object sender, EventArgs e) { // Do animation stuff here // Continue storyboard timer _LoopTimer.Begin(); } And in Silverlight, this works fine. But in WPF, I only hit MainLoop() once. Setting RepeatBehaviour to Forever doesn't help, either. So what's the right way to do this in WPF with a Storyboard? Thanks very much.

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  • C#: how to check and display the content of a folder?

    - by user147685
    I'm not sure whether this topics has been disscussed before or not, but I'm not sure the exact word to search for it. What method/class should I use? The program has 3 buttons: 1) for folder browsing, 2) scan for the selected folder content, and 3) open the file. When user browse the selected folder*(1), user click scan button to scan from the first file until the last available files and listed it text box(2)* and from that user can decide whether to open the files or not*(3)*. Here are what have I done so far (no 1 and 3): //For browse. private void browse2() { if (folderBrowserDialog1.ShowDialog() == DialogResult.OK) { this.txtDest.Text = folderBrowserDialog1.SelectedPath; } } //For opening folder. private void btnOpen_Click(object sender, EventArgs e) { try { Process.Start(txtDest.Text); } catch { MessageBox.Show("Please select one file/folder"); } }

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  • Write a C++ program to encrypt and decrypt certain codes.

    - by Amber
    Step 1: Write a function int GetText(char[],int); which fills a character array from a requested file. That is, the function should prompt the user to input the filename, and then read up to the number of characters given as the second argument, terminating when the number has been reached or when the end of file is encountered. The file should then be closed. The number of characters placed in the array is then returned as the value of the function. Every character in the file should be transferred to the array. Whitespace should not be removed. When testing, assume that no more than 5000 characters will be read. The function should be placed in a file called coding.cpp while the main will be in ass5.cpp. To enable the prototypes to be accessible, the file coding.h contains the prototypes for all the functions that are to be written in coding.cpp for this assignment. (You may write other functions. If they are called from any of the functions in coding.h, they must appear in coding.cpp where their prototypes should also appear. Do not alter coding.h. Any other functions written for this assignment should be placed, along with their prototypes, with the main function.) Step 2: Write a function int SimplifyText(char[],int); which simplifies the text in the first argument, an array containing the number of characters as given in the second argument, by converting all alphabetic characters to lower case, removing all non-alpha characters, and replacing multiple whitespace by one blank. Any leading whitespace at the beginning of the array should be removed completely. The resulting number of characters should be returned as the value of the function. Note that another array cannot appear in the function (as the file does not contain one). For example, if the array contained the 29 characters "The 39 Steps" by John Buchan (with the " appearing in the array), the simplified text would be the steps by john buchan of length 24. The array should not contain a null character at the end. Step 3: Using the file test.txt, test your program so far. You will need to write a function void PrintText(const char[],int,int); that prints out the contents of the array, whose length is the second argument, breaking the lines to exactly the number of characters in the third argument. Be warned that, if the array contains newlines (as it would when read from a file), lines will be broken earlier than the specified length. Step 4: Write a function void Caesar(const char[],int,char[],int); which takes the first argument array, with length given by the second argument and codes it into the third argument array, using the shift given in the fourth argument. The shift must be performed cyclicly and must also be able to handle negative shifts. Shifts exceeding 26 can be reduced by modulo arithmetic. (Is C++'s modulo operations on negative numbers a problem here?) Demonstrate that the test file, as simplified, can be coded and decoded using a given shift by listing the original input text, the simplified text (indicating the new length), the coded text and finally the decoded text. Step 5: The permutation cypher does not limit the character substitution to just a shift. In fact, each of the 26 characters is coded to one of the others in an arbitrary way. So, for example, a might become f, b become q, c become d, but a letter never remains the same. How the letters are rearranged can be specified using a seed to the random number generator. The code can then be decoded, if the decoder has the same random number generator and knows the seed. Write the function void Permute(const char[],int,char[],unsigned long); with the same first three arguments as Caesar above, with the fourth argument being the seed. The function will have to make up a permutation table as follows: To find what a is coded as, generate a random number from 1 to 25. Add that to a to get the coded letter. Mark that letter as used. For b, generate 1 to 24, then step that many letters after b, ignoring the used letter if encountered. For c, generate 1 to 23, ignoring a or b's codes if encountered. Wrap around at z. Here's an example, for only the 6 letters a, b, c, d, e, f. For the letter a, generate, from 1-5, a 2. Then a - c. c is marked as used. For the letter b, generate, from 1-4, a 3. So count 3 from b, skipping c (since it is marked as used) yielding the coding of b - f. Mark f as used. For c, generate, from 1-3, a 3. So count 3 from c, skipping f, giving a. Note the wrap at the last letter back to the first. And so on, yielding a - c b - f c - a d - b (it got a 2) e - d f - e Thus, for a given seed, a translation table is required. To decode a piece of text, we need the table generated to be re-arranged so that the right hand column is in order. In fact you can just store the table in the reverse way (e.g., if a gets encoded to c, put a opposite c is the table). Write a function called void DePermute(const char[],int,char[], unsigned long); to reverse the permutation cypher. Again, test your functions using the test file. At this point, any main program used to test these functions will not be required as part of the assignment. The remainder of the assignment uses some of these functions, and needs its own main function. When submitted, all the above functions will be tested by the marker's own main function. Step 6: If the seed number is unknown, decoding is difficult. Write a main program which: (i) reads in a piece of text using GetText; (ii) simplifies the text using SimplifyText; (iii) prints the text using PrintText; (iv) requests two letters to swap. If we think 'a' in the text should be 'q' we would type aq as input. The text would be modified by swapping the a's and q's, and the text reprinted. Repeat this last step until the user considers the text is decoded, when the input of the same letter twice (requesting a letter to be swapped with itself) terminates the program. Step 7: If we have a large enough sample of coded text, we can use knowledge of English to aid in finding the permutation. The first clue is in the frequency of occurrence of each letter. Write a function void LetterFreq(const char[],int,freq[]); which takes the piece of text given as the first two arguments (same as above) and returns in the 26 long array of structs (the third argument), the table of the frequency of the 26 letters. This frequency table should be in decreasing order of popularity. A simple Selection Sort will suffice. (This will be described in lectures.) When printed, this summary would look something like v x r s z j p t n c l h u o i b w d g e a q y k f m 168106 68 66 59 54 48 45 44 35 26 24 22 20 20 20 17 13 12 12 4 4 1 0 0 0 The formatting will require the use of input/output manipulators. See the header file for the definition of the struct called freq. Modify the program so that, before each swap is requested, the current frequency of the letters is printed. This does not require further calls to LetterFreq, however. You may use the traditional order of regular letter frequencies (E T A I O N S H R D L U) as a guide when deciding what characters to exchange. Step 8: The decoding process can be made more difficult if blank is also coded. That is, consider the alphabet to be 27 letters. Rewrite LetterFreq and your main program to handle blank as another character to code. In the above frequency order, space usually comes first.

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  • Flash CS, reference root from external class

    - by Lotus
    Hi, I made this class and I put it in the same package of Timeline.as (the Document Class): package { import flash.utils.Timer; import flash.events.TimerEvent; public class Counter2 extends Timer { public function Counter2(delay:Number, repeatCount:int=0) { super(delay, repeatCount); super.addEventListener(TimerEvent.TIMER, timerHandler); } public override function start():void { super.start(); } public override function stop():void { super.stop(); } public function timerHandler(evt:TimerEvent) { trace(evt.target.currentCount); } } } This class is instanciated in Timeline.as constructor. Is there any way to reference Timeline(root) from this class? And, if so, how? Thanks!

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  • Including a NSUserDefault password test in 1st Tab.m to load a loginView gives eror?

    - by Michael Robinson
    I have a name and password in NSUserDefaults for login. I have this in my 1stTab View.m class to test for presence and load a login/signup loginView.xib modally if there is no password or name stored in the app. Here is the pulling of the defaults: -(void)refreshFields { NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; usernameLabel.text = [defaults objectForKey:kUsernameKey]; passwordLabel.text = [defaults objectForKey:kPasswordKey]; { Here is the Test: - (void)viewDidAppear:(BOOL)animated { [self refreshFields]; [super viewDidAppear:animated]; if ([usernameLabel.text length] == 0 || [passwordLabel.text length] == 0) { LoginViewController * vc = [[[LoginViewController alloc] initWithNibName:@"LoginView" bundle:nil] autorelease]; [self presentModalViewController:vc animated: false]; } else { [[self tableView ]reloadData]; } } Thanks in advance, I'm getting this error in the console: * Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key usernameLabel.'

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  • How can i do the same thing with Gallery in Android

    - by Maxood
    I am navigating images with the clicks of next and previous buttons.Here is my code: package com.myapps.imagegallery; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; public class ImageGallery extends Activity { /** Called when the activity is first created. */ int imgs[] = {R.drawable.bluehills,R.drawable.lilies,R.drawable.sunset,R.drawable.winter}; String desc[] = {"Blue Hills", "Lillies", "Sunset", "Winter" }; int counter=0; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); final ImageView imgView = (ImageView)findViewById(R.id.ImageView01); imgView.setImageResource(imgs[counter]); final TextView tvDesc = (TextView)findViewById(R.id.tvDesc); Button btnNext = (Button)findViewById(R.id.btnNext); btnNext.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View arg0) { try{ // TODO Auto-generated method stub if (counter < desc.length -1) counter++; imgView.setImageResource(imgs[counter]); tvDesc.setText(desc[counter]); }catch(Exception e) { Toast.makeText(ImageGallery.this, e.toString(), Toast.LENGTH_SHORT).show(); } } }); Button btnPrev = (Button)findViewById(R.id.btnPre); btnPrev.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View arg0) { // TODO Auto-generated method stub try{ // TODO Auto-generated method stub if (counter > 0) counter--; imgView.setImageResource(imgs[counter]); tvDesc.setText(desc[counter]); }catch(Exception e) { Toast.makeText(ImageGallery.this, e.toString(), Toast.LENGTH_SHORT).show(); } }}); } } <?xml version="1.0" encoding="utf-8"?> <AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <ImageView android:id="@+id/ImageView01" android:layout_x="70dip" android:layout_width="200px" android:layout_height="200px" android:layout_y="90dip" > </ImageView> <TextView android:id="@+id/tvDesc" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" android:layout_x="90px" android:layout_y="300px" /> <Button android:layout_x="47dip" android:layout_height="wrap_content" android:text="Previous" android:layout_width="100px" android:id="@+id/btnPre" android:layout_y="341dip"> </Button> <Button android:layout_x="190dip" android:layout_height="wrap_content" android:text="Next" android:layout_width="100px" android:id="@+id/btnNext" android:layout_y="341dip"> </Button> </AbsoluteLayout>

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  • How to obtain a pointer out of a C++ vtable?

    - by Josh Haberman
    Say you have a C++ class like: class Foo { public: virtual ~Foo() {} virtual DoSomething() = 0; }; The C++ compiler translates a call into a vtable lookup: Foo* foo; // Translated by C++ to: // foo->vtable->DoSomething(foo); foo->DoSomething(); Suppose I was writing a JIT compiler and I wanted to obtain the address of the DoSomething() function for a particular instance of class Foo, so I can generate code that jumps to it directly instead of doing a table lookup and an indirect branch. My questions are: Is there any standard C++ way to do this (I'm almost sure the answer is no, but wanted to ask for the sake of completeness). Is there any remotely compiler-independent way of doing this, like a library someone has implemented that provides an API for accessing a vtable? I'm open to completely hacks, if they will work. For example, if I created my own derived class and could determine the address of its DoSomething method, I could assume that the vtable is the first (hidden) member of Foo and search through its vtable until I find my pointer value. However, I don't know a way of getting this address: if I write &DerivedFoo::DoSomething I get a pointer-to-member, which is something totally different. Maybe I could turn the pointer-to-member into the vtable offset. When I compile the following: class Foo { public: virtual ~Foo() {} virtual void DoSomething() = 0; }; void foo(Foo *f, void (Foo::*member)()) { (f->*member)(); } On GCC/x86-64, I get this assembly output: Disassembly of section .text: 0000000000000000 <_Z3fooP3FooMS_FvvE>: 0: 40 f6 c6 01 test sil,0x1 4: 48 89 74 24 e8 mov QWORD PTR [rsp-0x18],rsi 9: 48 89 54 24 f0 mov QWORD PTR [rsp-0x10],rdx e: 74 10 je 20 <_Z3fooP3FooMS_FvvE+0x20> 10: 48 01 d7 add rdi,rdx 13: 48 8b 07 mov rax,QWORD PTR [rdi] 16: 48 8b 74 30 ff mov rsi,QWORD PTR [rax+rsi*1-0x1] 1b: ff e6 jmp rsi 1d: 0f 1f 00 nop DWORD PTR [rax] 20: 48 01 d7 add rdi,rdx 23: ff e6 jmp rsi I don't fully understand what's going on here, but if I could reverse-engineer this or use an ABI spec I could generate a fragment like the above for each separate platform, as a way of obtaining a pointer out of a vtable.

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  • Why is javac 1.5 running so slowly compared with the Eclipse compiler?

    - by Simon Nickerson
    I have a Java Maven project with about 800 source files (some generated by javacc/JTB) which is taking a good 25 minutes to compile with javac. When I changed my pom.xml over to use the Eclipse compiler, it takes about 30 seconds to compile. Any suggestions as to why javac (1.5) is running so slowly? (I don't want to switch over to the Eclipse compiler permanently, as the plugin for Maven seems more than a little buggy.) I have a test case which easily reproduces the problem. The following code generates a number of source files in the default package. If you try to compile ImplementingClass.java with javac, it will seem to pause for an inordinately long time. import java.io.File; import java.io.FileNotFoundException; import java.io.PrintStream; public class CodeGenerator { private final static String PATH = System.getProperty("java.io.tmpdir"); private final static int NUM_TYPES = 1000; public static void main(String[] args) throws FileNotFoundException { PrintStream interfacePs = new PrintStream(PATH + File.separator + "Interface.java"); PrintStream abstractClassPs = new PrintStream(PATH + File.separator + "AbstractClass.java"); PrintStream implementingClassPs = new PrintStream(PATH + File.separator + "ImplementingClass.java"); interfacePs.println("public interface Interface<T> {"); abstractClassPs.println("public abstract class AbstractClass<T> implements Interface<T> {"); implementingClassPs.println("public class ImplementingClass extends AbstractClass<Object> {"); for (int i=0; i<NUM_TYPES; i++) { String nodeName = "Node" + i; PrintStream nodePs = new PrintStream(PATH + File.separator + nodeName + ".java"); nodePs.printf("public class %s { }\n", nodeName); nodePs.close(); interfacePs.printf("void visit(%s node, T obj);%n", nodeName); abstractClassPs.printf("public void visit(%s node, T obj) { System.out.println(obj.toString()); }%n", nodeName); } interfacePs.println("}"); abstractClassPs.println("}"); implementingClassPs.println("}"); interfacePs.close(); abstractClassPs.close(); implementingClassPs.close(); } }

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  • what happens to running/blocked runnables when executorservice is shutdown()

    - by prmatta
    I posted a question about a thread pattern today, and almost everyone suggested that I look into the ExecutorService. While I was looking into the ExecutorService, I think I am missing something. What happens if the service has a running or blocked threads, and someone calls ExecutorService.shutdown(). What happens to threads that are running or blocked? Does the ExecutorService wait for those threads to complete before it terminates? The reason I ask this is because a long time ago when I used to dabble in Java, they deprecated Thread.stop(), and I remember the right way of stopping a thread was to use sempahores and extend Thread when necessary: public void run () { while (!this.exit) { try { block(); //do something } catch (InterruptedException ie) { } } } public void stop () { this.exit = true; if (this.thread != null) { this.thread.interrupt(); this.thread = null; } } How does ExecutorService handle running threads?

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  • C operating system createprozess

    - by Tyzak
    hello, i'm new at C Programming (i learned c++) i want to create a process with windows.h at first i just want to start my main programm that creates a process ( -- starts an other programm) that's my code, but it doesn't really work, i removed every unnessasery line of code but "void sleep(700)" (or "sleep (700)" for testing if the windows methods work, but i get an error, that "sleep" cant be found. #include <iostream> #include <windows.h> #include <string> using namespace std; void main() { //bool ret; //startupinfo stupinfo; //prozess_information pro2info; //Getstartupinfo (&stupinfo); //createprozess(null, "C:\\bsss10\\betriebssystemePRA1.exe", null, null, false, create_new_console, null, // null, &stupinfo, &pro2info); sleep (700); cout<< "hello"; } thanks in advance

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  • Best approach to create a security environment in Java

    - by Tom Brito
    I need to create a desktop application that will run third party code, and I need to avoid the third party code from export by any way (web, clipboard, file io) informations from the application. Somethig like: public class MyClass { private String protectedData; public void doThirdPartyTask() { String unprotedtedData = unprotect(protectedData); ThirdPartyClass.doTask(unprotectedData); } private String unprotect(String data) { // ... } } class ThirdPartyClass { public static void doTask(String unprotectedData) { // Do task using unprotected data. // Malicious code may try to externalize the data. } } I'm reading about SecurityManager and AccessControler, but I'm still not sure what's the best approach to handle this. What should I read about to do this implementation?

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  • How do I let main thread suspend and wait for the System.Timer.Timer running

    - by Kelvin
    Hi I am using System.Timer.Timer I always get NULL after running my programme and it only works if I add this.sleep(6000). Suppose the reason is the main thread ends but the timer hasn't finished ... Here is the class and I call the class from my main form. Class class1 { string finalResult = ""; public string getNumber() { RunTimer(); return finalResult; } pubic void RunTimer () { timer = new System.Timers.Timer(30000); timer.Interval = 1000; timer.Elapsed += new System.Timers.ElapsedEventHandler(cal); timer.Start(); } private void cal(object sender,System.Timers.ElapsedEventArgs e) { finalResult += READFROMCOMPORT; } }

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  • UIWebView in multithread ViewController

    - by Tao
    I have a UIWebView in a viewcontroller, which has two methods as below. The question is if I pop out(tap back on navigation bar) this controller before the second thread is done, the app will crash after [super dealloc], because "Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread.". Any help would be really appreciated. -(void)viewDidAppear:(BOOL)animated { [super viewWillAppear:animated]; NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(load) object:nil]; [operationQueue addOperation:operation]; [operation release]; } -(void)load { [NSThread sleepForTimeInterval:5]; [self performSelectorOnMainThread:@selector(done) withObject:nil waitUntilDone:NO]; }

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  • problems calling webservices through the https connection

    - by shivaji123
    i have done an application in BlackBerry which takes username & password with url link which is a link of server here i am calling some webservices but it is doing the connection in https so when i take the username password & url link & hit the login button it basically calls a webservice but then the application connecting to the webservice for ever & after some time i get the error massage something "unreported exception the application is not responding" .& then the application crashes out.Also i am using the SOAP client library . this is the piece of code synchronized (this) { try { _httpconn = (HttpConnection) Connector.open(url,Connector.READ_WRITE);//Connector.READ_WRITE //_httpconn =(StreamConnection)Connector.open(url); //System.out.println("-----------httpsconnection() PART--------------------"); _httpconn.setRequestMethod(HttpConnection.POST); //_httpconn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); //System.out.println("-----------httpsconnection() PART- **-------------------"); _httpconn.setRequestProperty("SOAPAction", Constants.EXIST_STR); //System.out.println("-----------httpsconnection() PART-REQUEST -------------------"); _httpconn.setRequestProperty("Content-Type", "text/soap+xml"); //System.out.println("-----------httpsconnection() PART- CONTENT-------------------"); _httpconn.setRequestProperty("User-Agent", "kSOAP/1.0"); //System.out.println("-----------httpsconnection() PART-USER Agent-------------------"); String clen = Integer.toBinaryString(input.length()); _httpconn.setRequestProperty("Content-Length", clen); //System.out.println("-----------httpsconnection() Content-Length--------------------"); _out = _httpconn.openDataOutputStream(); //System.out.println(input+"-----------input--------------------"+url); _out.write(input.getBytes()); _out.flush(); // may or may not be needed. //int rc = _httpconn.getResponseCode(); int rc = _httpconn.getResponseCode(); if(rc == HttpConnection.HTTP_OK) { isComplete = true; _in = _httpconn.openInputStream(); msg = new StringBuffer(); byte[] data = new byte[1024]; int len = 0; int size = 0; while ( -1 != (len = _in.read(data)) ) { msg.append(new String(data, 0, len)); size += len; } responsData = msg.toString(); System.out.println("-----------responsData "+responsData); } if(responsData!=null) isSuccessful = true; stop(); } catch (InterruptedIOException interrIO) { //errStr = "Network Connection hasn't succedded. "+ //"Please check APN setting."; UiApplication.getUiApplication().invokeLater(new Runnable() { public void run() { Status.show("Network Connection hasn't succedded. "+ "Please try again later."); } }); isComplete = true; System.out.println(interrIO); stop(); } catch (IOException interrIO) { System.out.println("-----------IO EXCEPTION--------- "+interrIO); //errStr = "Network Connection hasn't succedded. "+ //"Please check APN setting." ; UiApplication.getUiApplication().invokeLater(new Runnable() { public void run() { Status.show("Network Connection hasn't succedded. "+ "Please try again later." ); } }); isComplete = true; System.out.println(interrIO); stop(); } catch (Exception e) { System.out.println(e); //errStr = "Unable to connect to the internet at this time. "+ //"Please try again later."; UiApplication.getUiApplication().invokeLater(new Runnable() { public void run() { Status.show("Unable to connect to the internet at this time. "+ "Please try again later." ); } }); isComplete = true; stop(); } finally { try { if(_httpconn != null) { _httpconn.close(); _httpconn = null; } if(_in != null) { _in.close(); _in = null; } if(_out != null) { _out.close(); _out = null; } } catch(Exception e) { System.out.println(e); UiApplication.getUiApplication().invokeLater(new Runnable() { public void run() { Status.show("Unable to connect to the internet at this time. "+ "Please try again later." ); } }); } } } } can anybody help me out. Thanks in advance

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  • Accessing controls defined inside DataRepeater within Page_Load

    - by xander
    I have a series of controls, 3 of which I need to disable. protected void AddToCart_Click(object sender, CommandEventArgs e) { //some other code... LinkButton ctrl = (LinkButton)sender; RepeaterItem rpItem = ctrl.NamingContainer as RepeaterItem; if (rpItem != null) { LinkButton btn = (LinkButton)rpItem.FindControl("btnRemoveFromCart"); btn.Visible = true; btn = (LinkButton)rpItem.FindControl("btnAddToCart"); btn.Visible = false; Image img = (Image)rpItem.FindControl("imgAdded"); img.Visible = true; } I want to access the DataRepeater and get to the controls to disable them. Only on Page_Load. protected void Page_Load(object sender, EventArgs e) { string galleryID = Session["selectedGalleryID"].ToString(); getItems(); if (!IsPostBack) { h1GalleryTitle.InnerText = Session["selectedGalleryName"].ToString(); //the code will go here to initially disable the controls that need to be disabled... } }

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  • Can I make ungetc unblock a blocking fgetc call?

    - by Paul Beckingham
    I would like to stuff an 'A' character back into stdin using ungetc on receipt of SIGUSR1. Imagine that I have a good reason for doing this. When calling foo(), the blocking read in stdin is not interrupted by the ungetc call on receipt of the signal. While I didn't expect this to work as is, I wonder if there is a way to achieve this - does anyone have suggestions? void handler (int sig) { ungetc ('A', stdin); } void foo () { signal (SIGUSR1, handler); while ((key = fgetc (stdin)) != EOF) { ... } }

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  • Order of calls to set functions when invoking a flex component

    - by Jason
    I have a component called a TableDataViewer that contains the following pieces of data and their associated set functions: [Bindable] private var _dataSetLoader:DataSetLoader; public function get dataSetLoader():DataSetLoader {return _dataSetLoader;} public function set dataSetLoader(dataSetLoader:DataSetLoader):void { trace("setting dSL"); _dataSetLoader = dataSetLoader; } [Bindable] private var _table:Table = null; public function set table(table:Table):void { trace("setting table"); _table = table; _dataSetLoader.load(_table.definition.id, "viewData", _table.definition.id); } This component is nested in another component as follows: <ve:TableDataViewer width="100%" height="100%" paddingTop="10" dataSetLoader="{_openTable.dataSetLoader}" table="{_openTable.table}"/> Looking at the trace in the logs, the call to set table is coming before the call to set dataSetLoader. Which is a real shame because set table() needs dataSetLoader to already be set in order to call its load() function. So my question is, is there a way to enforce an order on the calls to the set functions when declaring a component?

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  • how do i scroll through 100 photos in UIScrollView in IPhone

    - by mwangima
    I'm trying to scroll through images being downloaded from a users online album (like in the facebook iphone app) since i can't load all images into memory, i'm loading 3 at a time (prev,current & next). then removing image(prev-1) & image (next +1) from the uiscroller subviews. my logic works fine in the simulator but fails in the device with this error: [CALayer retain]: message sent to deallocated instance what could be the problem below is my code sample - (void)scrollViewDidEndDecelerating:(UIScrollView *)_scrollView { pageControlIsChangingPage = NO; CGFloat pageWidth = _scrollView.frame.size.width; int page = floor((_scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1; if (page1 && page<=(pageControl.numberOfPages-3)) { [self removeThisView:(page-2)]; [self removeThisView:(page+2)]; } if(page0) { NSLog(@"<< PREVIOUS"); [self showPhoto:(page-1)]; } [self showPhoto:page]; if(page<(pageControl.numberOfPages-1)) { //NSLog(@"NEXT "); [self showPhoto:page+1]; NSLog(@"FINISHED LOADING NEXT "); } } -(void) showPhoto:(NSInteger)index { CGFloat cx = scrollView.frame.size.width*index; CGFloat cy = 40; CGRect rect=CGRectMake( 0, 0,320, 480); rect.origin.x = cx; rect.origin.y = cy; AsyncImageView* asyncImage = [[AsyncImageView alloc] initWithFrame:rect]; asyncImage.tag = 999; NSURL *url = [NSURL URLWithString:[pics objectAtIndex:index]]; [asyncImage loadImageFromURL:url place:CGRectMake(150, 190, 30, 30) member:memberid isSlide:@"Yes" picId:[picsIds objectAtIndex:index]]; [scrollView addSubview:asyncImage]; [asyncImage release]; } -(void) removeThisView:(NSInteger)index { if(index<[[scrollView subviews] count] && [[scrollView subviews] objectAtIndex:index]!=nil){ if ([[[scrollView subviews] objectAtIndex:index] isKindOfClass:[AsyncImageView class]] || [[[scrollView subviews] objectAtIndex:index] isKindOfClass:[UIImageView class]]) { [[[scrollView subviews] objectAtIndex:index] removeFromSuperview]; } } } For the record it works OK in the simulator, but not the iphone device itself. any ideas will be appreciated. cheers, fred.

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  • Android: Autostart app and load preferences

    - by BBoom
    Hi, I have a problem with initializing my app properly after the autostart. I've managed to get an autostart to work, after a reboot the app is shown as started but the timer's are not. My guess is that the "onCreate" function of MyApp is not called when I call the context.startService(). The timers are set in the doActivity() function of MyApp. I would greatly appreciate any tips on what I could be doing wrong or links to good tutorials. :) The manifest: <activity android:name=".MyApp" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <receiver android:name="MyApp_Receiver"> <intent-filter> <action android:name="android.intent.action.BOOT_COMPLETED" /> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </receiver>[/syntax] MyApp_Receiver is a BoradcastReciever with the following two functions public void onReceive(Context context, Intent intent) { // Do Autostart if intent is "BOOT_COMPLETED" if ((intent.getAction() != null) && (intent.getAction().equals("android.intent.action.BOOT_COMPLETED"))) { // Start the service context.startService(new Intent(context, MyApp.class)); } // Else do activity else MAIN_ACTIVITY.doActivity(); } public static void setMainActivity(MyApp activity) { MAIN_ACTIVITY = activity; } MyApp extends PreferenceActivity and has an onCreate() and a doActivity(), the doActivity() reads out the preferences and sets a timer depending on them. public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Show preferences addPreferencesFromResource(R.xml.preferences);; // Register Preference Click Listeners getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this); // Prepare for one-shot alarms if (mIntent == null) { mIntent = new Intent(MyApp.this, MyApp_Receiver.class); mSender = PendingIntent.getBroadcast(MyApp.this, 0, mIntent, 0); MyApp_Receiver.setMainActivity(this); } // Refresh and set all timers on start doActivity(); }

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