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  • Yes, another thread question...

    - by Michael
    I can't understand why I am loosing control of my GUI even though I am implementing a thread to play a .wav file. Can someone pin point what is incorrect? #!/usr/bin/env python import wx, pyaudio, wave, easygui, thread, time, os, sys, traceback, threading import wx.lib.delayedresult as inbg isPaused = False isStopped = False class Frame(wx.Frame): def __init__(self): print 'Frame' wx.Frame.__init__(self, parent=None, id=-1, title="Jasmine", size=(720, 300)) #initialize panel panel = wx.Panel(self, -1) #initialize grid bag sizer = wx.GridBagSizer(hgap=20, vgap=20) #initialize buttons exitButton = wx.Button(panel, wx.ID_ANY, "Exit") pauseButton = wx.Button(panel, wx.ID_ANY, 'Pause') prevButton = wx.Button(panel, wx.ID_ANY, 'Prev') nextButton = wx.Button(panel, wx.ID_ANY, 'Next') stopButton = wx.Button(panel, wx.ID_ANY, 'Stop') #add widgets to sizer sizer.Add(pauseButton, pos=(1,10)) sizer.Add(prevButton, pos=(1,11)) sizer.Add(nextButton, pos=(1,12)) sizer.Add(stopButton, pos=(1,13)) sizer.Add(exitButton, pos=(5,13)) #initialize song time gauge #timeGauge = wx.Gauge(panel, 20) #sizer.Add(timeGauge, pos=(3,10), span=(0, 0)) #initialize menuFile widget menuFile = wx.Menu() menuFile.Append(0, "L&oad") menuFile.Append(1, "E&xit") menuBar = wx.MenuBar() menuBar.Append(menuFile, "&File") menuAbout = wx.Menu() menuAbout.Append(2, "A&bout...") menuAbout.AppendSeparator() menuBar.Append(menuAbout, "Help") self.SetMenuBar(menuBar) self.CreateStatusBar() self.SetStatusText("Welcome to Jasime!") #place sizer on panel panel.SetSizer(sizer) #initialize icon self.cd_image = wx.Image('cd_icon.png', wx.BITMAP_TYPE_PNG) self.temp = self.cd_image.ConvertToBitmap() self.size = self.temp.GetWidth(), self.temp.GetHeight() wx.StaticBitmap(parent=panel, bitmap=self.temp) #set binding self.Bind(wx.EVT_BUTTON, self.OnQuit, id=exitButton.GetId()) self.Bind(wx.EVT_BUTTON, self.pause, id=pauseButton.GetId()) self.Bind(wx.EVT_BUTTON, self.stop, id=stopButton.GetId()) self.Bind(wx.EVT_MENU, self.loadFile, id=0) self.Bind(wx.EVT_MENU, self.OnQuit, id=1) self.Bind(wx.EVT_MENU, self.OnAbout, id=2) #Load file usiing FileDialog, and create a thread for user control while running the file def loadFile(self, event): foo = wx.FileDialog(self, message="Open a .wav file...", defaultDir=os.getcwd(), defaultFile="", style=wx.FD_MULTIPLE) foo.ShowModal() self.queue = foo.GetPaths() self.threadID = 1 while len(self.queue) != 0: self.song = myThread(self.threadID, self.queue[0]) self.song.start() while self.song.isAlive(): time.sleep(2) self.queue.pop(0) self.threadID += 1 def OnQuit(self, event): self.Close() def OnAbout(self, event): wx.MessageBox("This is a great cup of tea.", "About Jasmine", wx.OK | wx.ICON_INFORMATION, self) def pause(self, event): global isPaused isPaused = not isPaused def stop(self, event): global isStopped isStopped = not isStopped class myThread (threading.Thread): def __init__(self, threadID, wf): self.threadID = threadID self.wf = wf threading.Thread.__init__(self) def run(self): global isPaused global isStopped self.waveFile = wave.open(self.wf, 'rb') #initialize stream self.p = pyaudio.PyAudio() self.stream = self.p.open(format = self.p.get_format_from_width(self.waveFile.getsampwidth()), channels = self.waveFile.getnchannels(), rate = self.waveFile.getframerate(), output = True) self.data = self.waveFile.readframes(1024) isPaused = False isStopped = False #main play loop, with pause event checking while self.data != '': # while isPaused != True: # if isStopped == False: self.stream.write(self.data) self.data = self.waveFile.readframes(1024) # elif isStopped == True: # self.stream.close() # self.p.terminate() self.stream.close() self.p.terminate() class App(wx.App): def OnInit(self): self.frame = Frame() self.frame.Show() self.SetTopWindow(self.frame) return True def main(): app = App() app.MainLoop() if __name__=='__main__': main()

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  • Delphi getting property value of a member from ClassType

    - by Kayode Yusuf
    I am implementing a Boilerplate feature - allow users to Change descriptions of some components - like Tlabels - at run time. e.g. TFooClass = Class ( TBaseClass) Label : Tlabel; ... End; Var FooClass : TFooClass; ... At Design time, the value Label's caption property is say - 'First Name', when the application is run, there is a feature that allows the user to change the caption value to say 'Other Name'. Once this is changed, the caption for the label for the class instance of FooClass is updated immediately. The problem now is if the user for whatever reason wants to revert back to the design time value of say 'First Name' , it seems impossible. I can use the RTTIContext methods and all that but I at the end of the day, it seems to require the instance of the class for me to change the value and since this has already being changed - I seem to to have hit a brick wall getting around it. My question is this - is there a way using the old RTTI methods or the new RTTIContext stuff to the property of a class' member without instantiating the class - i.e. getting the property from the ClassType definition. This is code snippet of my attempt at doing that : c : TRttiContext; z : TRttiInstanceType; w : TRttiProperty; Aform : Tform; .... Begin ..... Aform := Tform(FooClass); for vCount := 0 to AForm.ComponentCount-1 do begin vDummyComponent := AForm.Components[vCount]; if IsPublishedProp(vDummyComponent,'Caption') then begin c := TRttiContext.Create; try z := (c.GetType(vDummyComponent.ClassInfo) as TRttiInstanceType); w := z.GetProperty('Caption'); if w <> nil then Values[vOffset, 1] := w.GetValue(vDummyComponent.ClassType).AsString ..... ..... .... .... I am getting all sorts of errors and any help will be greatly appreciated.

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  • How do you clear RootLayoutPanel in GWT?

    - by kerrr
    I have Buttons attached to elements on the modules entrypoint html page using RootPanel.get("foo").add(button). If I subsequently create a LayoutPanel and attach it using RootLayoutPanel.get.add(layoutpanal) then the buttons cannot be clicked. This is all fine. If I then try and remove the layoutpanel or clear the RootLayoutPanel the buttons still cannot be clicked. Any ideas how to clear this? Have I missed a step or should you simply never try and get back to using a page's RootPanel if you have used a RootLayoutPanel? Sample code: public void onModuleLoad(){ final LayoutPanel lp1=new LayoutPanel(); ClickPanel ping=new ClickPanel("Ping"); ping.getElement().getStyle().setBackgroundColor( "#fdd" ); ping.addClickHandler( new ClickHandler(){ @Override public void onClick( ClickEvent event ){ Window.alert( "Ping!!!" ); //lp1.removeFromParent(); //RootLayoutPanel.get().remove(lp1); //RootLayoutPanel.get().removeFromParent(); RootLayoutPanel.get().clear(); } } ); ClickPanel bong=new ClickPanel("Bong"); bong.getElement().getStyle().setBackgroundColor( "#ddf" ); bong.addClickHandler( new ClickHandler(){ @Override public void onClick( ClickEvent event ){ Window.alert( "Bong!!!" ); } } ); lp1.add( ping ); lp1.setWidgetLeftWidth( ping, 100, Style.Unit.PX, 500, Style.Unit.PX ); lp1.setWidgetTopHeight( ping, 100, Style.Unit.PX, 500, Style.Unit.PX ); lp1.add( bong ); lp1.setWidgetLeftWidth( bong, 50, Style.Unit.PCT, 600, Style.Unit.PX ); lp1.setWidgetTopHeight( bong, 50, Style.Unit.PCT, 200, Style.Unit.PX ); Button b=new Button("Click Me"); b.addClickHandler( new ClickHandler(){ @Override public void onClick( ClickEvent event ){ RootLayoutPanel.get().add( lp1 ); } } ); RootPanel.get("button1").add( b ); } ClickPanel is simply overrides HTMLPanel implementing HasClickHandelers. Clicking "Click Me" opens the layout panel. Clicking the panel ping gets rid of the layout panel, but the button "Click Me" cannot be clicked. I've tried various options.

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  • Maven2 not compiling source

    - by Grep
    Hi, I am new to Maven2 and have been having an issue with the compiling of the source for a RAR. Maven currently copies all the information located at my sourceDirectory instead of compiling it even though the console states that the source is being compiled. If I navigate to the sourceDirectory I find all my source files with no compiled class files. I have tried changing my outputDirectory to a different location and when I inspect this directory I find that it only copied my source files instead of compiling them. I have added an example of my POM. Any advice would be appreciated and please keep in mind I have only started learning/implementing Maven2 yesterday :) <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <artifactId>MyApp</artifactId> <groupId>.</groupId> <version>4</version> <packaging>rar</packaging> <name>MyApp rar</name> <build> <directory>target\${artifactId}-${version}</directory> <resources> <resource> <directory>..\gen-src</directory> <excludes> <exclude>util.jar</exclude> </excludes> </resource> <resource> <directory>..\domain</directory> </resource> </resources> <sourceDirectory>target\${artifactId}-${version}</sourceDirectory> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-rar-plugin</artifactId> <configuration> <workDirectory>target\${artifactId}-${version}\classes</workDirectory> <outputDirectory>target</outputDirectory> <finalName>MyApp${version}</finalName> <raXmlFile>${workDirectory}\META-INF\ra.xml</raXmlFile> </configuration> </plugin> </plugins> </build> </project>

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  • std::ostream interface to an OLE IStream

    - by PaulH
    I have a Visual Studio 2008 C++ application using IStreams. I would like to use the IStream connection in a std::ostream. Something like this: IStream* stream = /*create valid IStream instance...*/; IStreamBuf< WIN32_FIND_DATA > sb( stream ); std::ostream os( &sb ); WIN32_FIND_DATA d = { 0 }; // send the structure along the IStream os << d; To accomplish this, I've implemented the following code: template< class _CharT, class _Traits > inline std::basic_ostream< _CharT, _Traits >& operator<<( std::basic_ostream< _CharT, _Traits >& os, const WIN32_FIND_DATA& i ) { const _CharT* c = reinterpret_cast< const _CharT* >( &i ); const _CharT* const end = c + sizeof( WIN32_FIND_DATA ) / sizeof( _CharT ); for( c; c < end; ++c ) os << *c; return os; } template< typename T > class IStreamBuf : public std::streambuf { public: IStreamBuf( IStream* stream ) : stream_( stream ) { setp( reinterpret_cast< char* >( &buffer_ ), reinterpret_cast< char* >( &buffer_ ) + sizeof( buffer_ ) ); }; virtual ~IStreamBuf() { sync(); }; protected: traits_type::int_type FlushBuffer() { int bytes = std::min< int >( pptr() - pbase(), sizeof( buffer_ ) ); DWORD written = 0; HRESULT hr = stream_->Write( &buffer_, bytes, &written ); if( FAILED( hr ) ) { return traits_type::eof(); } pbump( -bytes ); return bytes; }; virtual int sync() { if( FlushBuffer() == traits_type::eof() ) return -1; return 0; }; traits_type::int_type overflow( traits_type::int_type ch ) { if( FlushBuffer() == traits_type::eof() ) return traits_type::eof(); if( ch != traits_type::eof() ) { *pptr() = ch; pbump( 1 ); } return ch; }; private: /// data queued up to be sent T buffer_; /// output stream IStream* stream_; }; // class IStreamBuf Yes, the code compiles and seems to work, but I've not had the pleasure of implementing a std::streambuf before. So, I'd just like to know if it's correct and complete. Thanks, PaulH

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  • Strange behaviour with mediaplayer and seekTo

    - by Mathias Lin
    I'm implementing a custom video player because I need custom video controls. I have an app with only one activity, which on startup shall start playing a video right away. Now, the problem I have is: I don't want the video to start from the beginning, but from a later position. Therefore I do a seekTo(16867). Since seekTo is asynchronous, I place the start call of the mediaplayer (player.start()) in the onSeekComplete of the onSeekCompleteListener. The strange behaviour I experience though is that I can see/hear the video playing from the beginning for a few millisecs before it actually plays from/jumps to the position I seeked to. But - on the other hand - the Log output I call before the player.start returns the correct position 16867, where I seeked to. Below is the relevant code section, the complete class is at http://pastebin.com/jqAAFsuX (I'm on Nexus One / 2.2 StageFright) private void playVideo(String url) { try { btnVideoPause.setEnabled(false); if (player==null) { player=new MediaPlayer(); player.setScreenOnWhilePlaying(true); } else { player.stop(); player.reset(); } url = "/sdcard/myapp/main/videos/main.mp4"; // <--- just for test purposes hardcoded here now player.setDataSource(url); player.setDisplay(holder); player.setAudioStreamType(AudioManager.STREAM_MUSIC); player.setOnCompletionListener(this); player.setOnPreparedListener(this); player.setOnSeekCompleteListener(new MediaPlayer.OnSeekCompleteListener() { public void onSeekComplete(MediaPlayer mediaPlayer) { Log.d("APP", "current pos... "+ player.getCurrentPosition() ); player.start(); // <------------------ start video on seek completed player.setOnSeekCompleteListener(null); } }); player.prepareAsync(); } catch (Throwable t) { Log.e(TAG, "Exception in btnVideoPause prep", t); } } public void onPrepared(MediaPlayer mediaplayer) { width=player.getVideoWidth(); height=player.getVideoHeight(); if (width!=0 && height!=0) { holder.setFixedSize(width, height); progressBar.setProgress(0); progressBar.setMax(player.getDuration()); player.seekTo(16867); // <------------------ seeking to position } btnVideoPause.setEnabled(true); }

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  • JSON or YAML encoding in GWT/Java on both client and server

    - by KennethJ
    I'm looking for a super simple JSON or YAML library (not particularly bothered which one) written in Java, and can be used in both GWT on the client, and in its original Java form on the server. What I'm trying to do is this: I have my models, which are shared between the client and the server, and these are the primary source of data interchange. I want to design the web service in between to be as simple as possible, and decided to take the RESTful approach. My problem is that I know our application will grow substantially in the future, and writing all the getters, setters, serialization, factories, etc. by hand fills me with absolute dread. So in order to avoid it, I decided to implement annotations to keep track of attributes on the models. The reason I can't just serialize everything directly, using GWT's own one, or one which works through reflection, is because we need a certain amount of logic going on in the serialization process. I.e. whether references to other models get serialized during the serialization of the original model, or whether an ID is just passed, and general simple things like that. I've then written an annotation processor to preprocess my shared models and generate an implementing class with all the getters, setters, serialization, lazy-loading, etc. To make a long story short, I need some type of simple YAML or JSON library, which allows me to encode and decode manually, so I can generate this code through my annotation processor. I have had a look around the interwebs, but every single one I ran into supported some reflection which, while all fine and dandy, make it pretty much useless for GWT. And in the case of GWT's own JSON library, it uses JSNI for speed purposes, making it useless server side. One solution I did think about involved writing writing two sets of serialization methods on the models, one for the client and one for the server, but I'd rather not do that. Also, I'm pretty new to GWT, and even though I have done a lot of Java, it was back in the 1.2 days, so it's a bit rusty. So if you think I'm going about this problem completely the wrong way, I'm open to suggestions.

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  • Multi-Threading Question Concerning WPF

    - by Andrew
    Hello, I'm a newbie to threading, and I don't really know how to code a particular task. I would like to handle a mouse click event on a window that will kick off a while loop in a seperate thread. This thread, which is distinct from the UI thread, should call a function in the while loop which updates a label on the window being serviced by the UI thread. The while loop should stop running when the left mouse button is no longer being pressed. All the loop does is increment a counter, and then repeatedly call the function which displays the updated value in the window. The code for the window and all of the threading is given below (I keep getting some error about STA threading, but don't know where to put the attribute). Also, I'm hoping to use this solution, if it ever works, in another project that makes asynchronous calls elsewhere to a service via wcf, so I was hoping not to make any application-wide special configurations, since I'm really new to multi-threading and am quite worried about breaking other code in a larger program... Here's what I have: <Window x:Class="WpfApplication2.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WpfApplication2" Name="MyMainWindow" Title="MainWindow" Width="200" Height="150" PreviewMouseLeftButtonDown="MyMainWindow_PreviewMouseLeftButtonDown"> <Label Height="28" Name="CounterLbl" /> </Window> And here's the code-behind: using System.Windows; using System.Windows.Input; using System.Threading; namespace WpfApplication2 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { private int counter = 0; public MainWindow() { InitializeComponent(); } private delegate void EmptyDelegate(); private void MyMainWindow_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e) { Thread counterThread = new Thread(new ThreadStart(MyThread)); counterThread.Start(); } private void MyThread() { while (Mouse.LeftButton == MouseButtonState.Pressed) { counter++; Dispatcher.Invoke(new EmptyDelegate(UpdateLabelContents), null); } } private void UpdateLabelContents() { CounterLbl.Content = counter.ToString(); } } } Anyways, multi-threading is really new to me, and I don't have any experience implementing it, so any thoughts or suggestions are welcome! Thanks, Andrew

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  • Objective-c design advice for use of different data sources, swapping between test and live

    - by user200341
    I'm in the process of designing an application that is part of a larger piece of work, depending on other people to build an API that the app can make use of to retrieve data. While I was thinking about how to setup this project and design the architecture around it, something occurred to me, and I'm sure many people have been in similar situations. Since my work is depending on other people to complete their tasks, and a test server, this slows work down at my end. So the question is: What's the best practice for creating test repositories and classes, implementing them, and not having to depend on altering several places in the code to swap between the test classes and the actual repositories / proper api calls. Contemplate the following scenario: GetDataFromApiCommand *getDataCommand = [[GetDataFromApiCommand alloc]init]; getDataCommand.delegate = self; [getDataCommand getData]; Once the data is available via the API, "GetDataFromApiCommand" could use the actual API, but until then a set of mock data could be returned upon the call of [getDataCommand getData] There might be multiple instances of this, in various places in the code, so replacing all of them wherever they are, is a slow and painful process which inevitably leads to one or two being overlooked. In strongly typed languages we could use dependency injection and just alter one place. In objective-c a factory pattern could be implemented, but is that the best route to go for this? GetDataFromApiCommand *getDataCommand = [GetDataFromApiCommandFactory buildGetDataFromApiCommand]; getDataCommand.delegate = self; [getDataCommand getData]; What is the best practices to achieve this result? Since this would be most useful, even if you have the actual API available, to run tests, or work off-line, the ApiCommands would not necessarily have to be replaced permanently, but the option to select "Do I want to use TestApiCommand or ApiCommand". It is more interesting to have the option to switch between: All commands are test and All command use the live API, rather than selecting them one by one, however that would also be useful to do for testing one or two actual API commands, mixing them with test data. EDIT The way I have chosen to go with this is to use the factory pattern. I set up the factory as follows: @implementation ApiCommandFactory + (ApiCommand *)newApiCommand { // return [[ApiCommand alloc]init]; return [[ApiCommandMock alloc]init]; } @end And anywhere I want to use the ApiCommand class: GetDataFromApiCommand *getDataCommand = [ApiCommandFactory newApiCommand]; When the actual API call is required, the comments can be removed and the mock can be commented out. Using new in the message name implies that who ever uses the factory to get an object, is responsible for releasing it (since we want to avoid autorelease on the iPhone). If additional parameters are required, the factory needs to take these into consideration i.e: [ApiCommandFactory newSecondApiCommand:@"param1"]; This will work quite well with repositories as well.

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  • Persistent (purely functional) Red-Black trees on disk performance

    - by Waneck
    I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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  • Help with C# program design implementation: multiple array of lists or a better way?

    - by Bob
    I'm creating a 2D tile-based RPG in XNA and am in the initial design phase. I was thinking of how I want my tile engine to work and came up with a rough sketch. Basically I want a grid of tiles, but at each tile location I want to be able to add more than one tile and have an offset. I'd like this so that I could do something like add individual trees on the world map to give more flair. Or set bottles on a bar in some town without having to draw a bunch of different bar tiles with varying bottles. But maybe my reach is greater than my grasp. I went to implement the idea and had something like this in my Map object: List<Tile>[,] Grid; But then I thought about it. Let's say I had a world map of 200x200, which would actually be pretty small as far as RPGs go. That would amount to 40,000 Lists. To my mind I think there has to be a better way. Now this IS pre-mature optimization. I don't know if the way I happen to design my maps and game will be able to handle this, but it seems needlessly inefficient and something that could creep up if my game gets more complex. One idea I have is to make the offset and the multiple tiles optional so that I'm only paying for them when needed. But I'm not sure how I'd do this. A multiple array of objects? object[,] Grid; So here's my criteria: A 2D grid of tile locations Each tile location has a minimum of 1 tile, but can optionally have more Each extra tile can optionally have an x and y offset for pinpoint placement Can anyone help with some ideas for implementing such a design (don't need it done for me, just ideas) while keeping memory usage to a minimum? If you need more background here's roughly what my Map and Tile objects amount to: public struct Map { public Texture2D Texture; public List<Rectangle> Sources; //Source Rectangles for where in Texture to get the sprite public List<Tile>[,] Grid; } public struct Tile { public int Index; //Where in Sources to find the source Rectangle public int X, Y; //Optional offsets }

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  • Some clarification on rvalue references

    - by Dennis Zickefoose
    First: where are std::move and std::forward defined? I know what they do, but I can't find proof that any standard header is required to include them. In gcc44 sometimes std::move is available, and sometimes its not, so a definitive include directive would be useful. When implementing move semantics, the source is presumably left in an undefined state. Should this state necessarily be a valid state for the object? Obviously, you need to be able to call the object's destructor, and be able to assign to it by whatever means the class exposes. But should other operations be valid? I suppose what I'm asking is, if your class guarantees certain invariants, should you strive to enforce those invariants when the user has said they don't care about them anymore? Next: when you don't care about move semantics, are there any limitations that would cause a non-const reference to be preferred over an rvalue reference when dealing with function parameters? void function(T&); over void function(T&&); From a caller's perspective, being able to pass functions temporary values is occasionally useful, so it seems as though one should grant that option whenever it is feasible to do so. And rvalue references are themselves lvalues, so you can't inadvertently call a move-constructor instead of a copy-constructor, or something like that. I don't see a downside, but I'm sure there is one. Which brings me to my final question. You still can not bind temporaries to non-const references. But you can bind them to non-const rvalue references. And you can then pass along that reference as a non-const reference in another function. void function1(int& r) { r++; } void function2(int&& r) { function1(r); } int main() { function1(5); //bad function2(5); //good } Besides the fact that it doesn't do anything, is there anything wrong with that code? My gut says of course not, since changing rvalue references is kind of the whole point to their existence. And if the passed value is legitimately const, the compiler will catch it and yell at you. But by all appearances, this is a runaround of a mechanism that was presumably put in place for a reason, so I'd just like confirmation that I'm not doing anything foolish.

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  • Foreign key pointing to different tables

    - by Álvaro G. Vicario
    I'm implementing a table per subclass design I discussed in a previous question. It's a product database where products can have very different attributes depending on their type, but attributes are fixed for each type and types are not manageable at all. I have a master table that holds common attributes: product_type ============ product_type_id INT product_type_name VARCHAR E.g.: 1 'Magazine' 2 'Web site' product ======= product_id INT product_name VARCHAR product_type_id INT -> Foreign key to product_type.product_type_id valid_since DATETIME valid_to DATETIME E.g. 1 'Foo Magazine' 1 '1998-12-01' NULL 2 'Bar Weekly Review' 1 '2005-01-01' NULL 3 'E-commerce App' 2 '2009-10-15' NULL 4 'CMS' 2 '2010-02-01' NULL ... and one subtable for each product type: item_magazine ============= item_magazine_id INT title VARCHAR product_id INT -> Foreign key to product.product_id issue_number INT pages INT copies INT close_date DATETIME release_date DATETIME E.g. 1 'Foo Magazine Regular Issue' 1 89 52 150000 '2010-06-25' '2010-06-31' 2 'Foo Magazine Summer Special' 1 90 60 175000 '2010-07-25' '2010-07-31' 3 'Bar Weekly Review Regular Issue' 2 12 16 20000 '2010-06-01' '2010-06-02' item_web_site ============= item_web_site_id INT name VARCHAR product_id INT -> Foreign key to product.product_id bandwidth INT hits INT date_from DATETIME date_to DATETIME E.g. 1 'The Carpet Store' 3 10 90000 '2010-06-01' NULL 2 'Penauts R Us' 3 20 180000 '2010-08-01' NULL 3 'Springfield Cattle Fair' 4 15 150000 '2010-05-01' '2010-10-31' Now I want to add some fees that relate to one specific item. Since there are very little subtypes, it's feasible to do this: fee === fee_id INT fee_description VARCHAR item_magazine_id INT -> Foreign key to item_magazine.item_magazine_id item_web_site_id INT -> Foreign key to item_web_site.item_web_site_id net_price DECIMAL E.g.: 1 'Front cover' 2 NULL 1999.99 2 'Half page' 2 NULL 500.00 3 'Square banner' NULL 3 790.50 4 'Animation' NULL 3 2000.00 I have tight foreign keys to handle cascaded editions and I presume I can add a constraint so only one of the IDs is NOT NULL. However, my intuition suggests that it would be cleaner to get rid of the item_WHATEVER_id columns and keep a separate table: fee_to_item =========== fee_id INT -> Foreign key to fee.fee_id product_id INT -> Foreign key to product.product_id item_id INT -> ??? But I can't figure out how to create foreign keys on item_id since the source table varies depending on product_id. Should I stick to my original idea?

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  • How can I send multiple types of objects across Protobuf?

    - by cyclotis04
    I'm implementing a client-server application, and am looking into various ways to serialize and transmit data. I began working with Xml Serializers, which worked rather well, but generate data slowly, and make large objects, especially when they need to be sent over the net. So I started looking into Protobuf, and protobuf-net. My problem lies in the fact that protobuf doesn't sent type information with it. With Xml Serializers, I was able to build a wrapper which would send and receive any various (serializable) object over the same stream, since object serialized into Xml contain the type name of the object. ObjectSocket socket = new ObjectSocket(); socket.AddTypeHandler(typeof(string)); // Tells the socket the types socket.AddTypeHandler(typeof(int)); // of objects we will want socket.AddTypeHandler(typeof(bool)); // to send and receive. socket.AddTypeHandler(typeof(Person)); // When it gets data, it looks for socket.AddTypeHandler(typeof(Address)); // these types in the Xml, then uses // the appropriate serializer. socket.Connect(_host, _port); socket.Send(new Person() { ... }); socket.Send(new Address() { ... }); ... Object o = socket.Read(); Type oType = o.GetType(); if (oType == typeof(Person)) HandlePerson(o as Person); else if (oType == typeof(Address)) HandleAddress(o as Address); ... I've considered a few solutions to this, including creating a master "state" type class, which is the only type of object sent over my socket. This moves away from the functionality I've worked out with Xml Serializers, though, so I'd like to avoid that direction. The second option would be to wrap protobuf objects in some type of wrapper, which defines the type of object. (This wrapper would also include information such as packet ID, and destination.) It seems silly to use protobuf-net to serialize an object, then stick that stream between Xml tags, but I've considered it. Is there an easy way to get this functionality out of protobuf or protobuf-net? I've come up with a third solution, and posted it below, but if you have a better one, please post it too!

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  • Precise explanation of JavaScript <-> DOM circular reference issue

    - by Joey Adams
    One of the touted advantages of jQuery.data versus raw expando properties (arbitrary attributes you can assign to DOM nodes) is that jQuery.data is "safe from circular references and therefore free from memory leaks". An article from Google titled "Optimizing JavaScript code" goes into more detail: The most common memory leaks for web applications involve circular references between the JavaScript script engine and the browsers' C++ objects' implementing the DOM (e.g. between the JavaScript script engine and Internet Explorer's COM infrastructure, or between the JavaScript engine and Firefox XPCOM infrastructure). It lists two examples of circular reference patterns: DOM element → event handler → closure scope → DOM DOM element → via expando → intermediary object → DOM element However, if a reference cycle between a DOM node and a JavaScript object produces a memory leak, doesn't this mean that any non-trivial event handler (e.g. onclick) will produce such a leak? I don't see how it's even possible for an event handler to avoid a reference cycle, because the way I see it: The DOM element references the event handler. The event handler references the DOM (either directly or indirectly). In any case, it's almost impossible to avoid referencing window in any interesting event handler, short of writing a setInterval loop that reads actions from a global queue. Can someone provide a precise explanation of the JavaScript ↔ DOM circular reference problem? Things I'd like clarified: What browsers are effected? A comment in the jQuery source specifically mentions IE6-7, but the Google article suggests Firefox is also affected. Are expando properties and event handlers somehow different concerning memory leaks? Or are both of these code snippets susceptible to the same kind of memory leak? // Create an expando that references to its own element. var elem = document.getElementById('foo'); elem.myself = elem; // Create an event handler that references its own element. var elem = document.getElementById('foo'); elem.onclick = function() { elem.style.display = 'none'; }; If a page leaks memory due to a circular reference, does the leak persist until the entire browser application is closed, or is the memory freed when the window/tab is closed?

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  • Scalable Database Tagging Schema

    - by Longpoke
    EDIT: To people building tagging systems. Don't read this. It is not what you are looking for. I asked this when I wasn't aware that RDBMS all have their own optimization methods, just use a simple many to many scheme. I have a posting system that has millions of posts. Each post can have an infinite number of tags associated with it. Users can create tags which have notes, date created, owner, etc. A tag is almost like a post itself, because people can post notes about the tag. Each tag association has an owner and date, so we can see who added the tag and when. My question is how can I implement this? It has to be fast searching posts by tag, or tags by post. Also, users can add tags to posts by typing the name into a field, kind of like the google search bar, it has to fill in the rest of the tag name for you. I have 3 solutions at the moment, but not sure which is the best, or if there is a better way. Note that I'm not showing the layout of notes since it will be trivial once I get a proper solution for tags. Method 1. Linked list tagId in post points to a linked list in tag_assoc, the application must traverse the list until flink=0 post: id, content, ownerId, date, tagId, notesId tag_assoc: id, tagId, ownerId, flink tag: id, name, notesId Method 2. Denormalization tags is simply a VARCHAR or TEXT field containing a tab delimited array of tagId:ownerId. It cannot be a fixed size. post: id, content, ownerId, date, tags, notesId tag: id, name, notesId Method 3. Toxi (from: http://www.pui.ch/phred/archives/2005/04/tags-database-schemas.html, also same thing here: http://stackoverflow.com/questions/20856/how-do-you-recommend-implementing-tags-or-tagging) post: id, content, ownerId, date, notesId tag_assoc: ownerId, tagId, postId tag: id, name, notesId Method 3 raises the question, how fast will it be to iterate through every single row in tag_assoc? Methods 1 and 2 should be fast for returning tags by post, but for posts by tag, another lookup table must be made. The last thing I have to worry about is optimizing searching tags by name, I have not worked that out yet. I made an ASCII diagram here: http://pastebin.com/f1c4e0e53

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  • Change the size of the panel dynamically

    - by C. Karunarathne
    Hi! I am implementing an application that needs to drag and drop image boxes in a panel.Image boxes are added dynamically from the program and so I have set the autoscroll property to true in panel.But when I have drag out the boxes at bottom in the panel the panel size got reduced.I have put autosize property false in panel.The panel is docked in another panel.I want to set the size of panel at run time.How can I achieve this. public form1(int[,] dummy, int columnSize, int rowSize) { this.dummy= dummy; numOfColumns = columnSize; numOfRows = rowSize; getData(); addIds = addIdArray; data = mylist; InitializeComponent(); //panel1.MinimumSize = new Size(columnSize * 40, rowSize * 40); //panel1.Height = rowSize * 40; //panel1.Width = columnSize * 40; //panel4.Height = rowSize * 40; //panel4.Width = columnSize * 40; int x, y; Structures.EmptyRectSpace space = new Structures.EmptyRectSpace(); for (int i = 0; i < data.Count; i++)// set picture boxes { space = (Structures.EmptyRectSpace)data[i]; x = space.startingJ; y = space.startingI; int h, w; h = space.length; w = space.width; p = new PictureBox(); p.Width = w * 40; p.Height = h * 40; p.BackColor = Color.DarkGreen; p.Image = Properties.Resources.v; p.BorderStyle = BorderStyle.FixedSingle; p.Name = addIdArray[i].ToString(); p.Location = new Point((x + 1 - w) * 40, (y + 1 - h) * 40); this.panel1.Controls.Add(p); } foreach (Control c in this.panel1.Controls) { if (c is PictureBox) { c.MouseDown += new MouseEventHandler(pictureBox1_MouseDown); } } this.panel1.DragOver += new System.Windows.Forms.DragEventHandler(this.panel1_DragOver); panel1.DragOver += new DragEventHandler(panel1_DragOver); panel1.DragDrop += new DragEventHandler(panel1_DragDrop); panel1.AllowDrop = true; panel2.AllowDrop = true; foreach (Control c in this.panel2.Controls) { c.MouseDown += new MouseEventHandler(pictureBox1_MouseDown); } this.panel2.DragOver += new System.Windows.Forms.DragEventHandler(this.panel2_DragOver); panel2.DragOver += new DragEventHandler(panel2_DragOver); panel2.DragDrop += new DragEventHandler(panel2_DragDrop); } This is the constructor of the form that contained panel.When it loaded the picture boxes must be added to the panel and there drag drop events of panel are implemented. Please give me a helping hand..

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  • Using events in threads between processes - C

    - by Jamie Keeling
    Hello all! I have an application consisting of two windows, one communicates to the other and sends it a struct constaining two integers (In this case two rolls of a dice). I will be using events for the following circumstances: Process a sends data to process b, process b displays data Process a closes, in turn closing process b Process b closes a, in turn closing process a I have noticed that if the second process is constantly waiting for the first process to send data then the program will be just sat waiting, which is where the idea of implementing threads on each process occurred and I have started to implement this already. The problem i'm having is that I don't exactly have a lot of experience with threads and events so I'm not sure of the best way to actually implement what I want to do. Following is a small snippet of what I have so far in the producer application; Create thread: case IDM_FILE_ROLLDICE: { hDiceRoll = CreateThread( NULL, // lpThreadAttributes (default) 0, // dwStackSize (default) ThreadFunc(hMainWindow), // lpStartAddress NULL, // lpParameter 0, // dwCreationFlags &hDiceID // lpThreadId (returned by function) ); } break; The data being sent to the other process: DWORD WINAPI ThreadFunc(LPVOID passedHandle) { HANDLE hMainHandle = *((HANDLE*)passedHandle); WCHAR buffer[256]; LPCTSTR pBuf; LPVOID lpMsgBuf; LPVOID lpDisplayBuf; struct diceData storage; HANDLE hMapFile; DWORD dw; //Roll dice and store results in variable storage = RollDice(); hMapFile = CreateFileMapping( (HANDLE)0xFFFFFFFF, // use paging file NULL, // default security PAGE_READWRITE, // read/write access 0, // maximum object size (high-order DWORD) BUF_SIZE, // maximum object size (low-order DWORD) szName); // name of mapping object if (hMapFile == NULL) { dw = GetLastError(); MessageBox(hMainHandle,L"Could not create file mapping object",L"Error",MB_OK); return 1; } pBuf = (LPTSTR) MapViewOfFile(hMapFile, // handle to map object FILE_MAP_ALL_ACCESS, // read/write permission 0, 0, BUF_SIZE); if (pBuf == NULL) { MessageBox(hMainHandle,L"Could not map view of file",L"Error",MB_OK); CloseHandle(hMapFile); return 1; } CopyMemory((PVOID)pBuf, &storage, (_tcslen(szMsg) * sizeof(TCHAR))); //_getch(); MessageBox(hMainHandle,L"Completed!",L"Success",MB_OK); UnmapViewOfFile(pBuf); return 0; } I'm trying to find out how I would integrate an event with the threaded code to signify to the other process that something has happened, I've seen an MSDN article on using events but it's just confused me if anything, I'm coming up on empty whilst searching on the internet too. Thanks for any help Edit: I can only use the Create/Set/Open methods for events, sorry for not mentioning it earlier.

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  • HTML-like GUI Framework in Java

    - by wintermute
    I was recently brought onto a project where we are developing a lot GUI elements for BlackBerry devices. The standard RIM APIs are pretty basic, almost never do what is required and are difficult or impossible to extend, so we end up re-implementing chunks of it. Currently the code we have isn't super organized and factored so there are lots of little tricks that get implemented over and over again. I had a thought about how to aid development efforts on this platform and wanted to see if the community could tell me if I'm still sane or if I've gone totally nuts. By far, the biggest organizational problem I've run into is making sure that each screen is laid out properly with proper padding and such. The current approach is to manually keep track of padding like so: protected void sublayout(int width, int height) { final int padding = 5; int y = padding; int x = padding; layoutChild(_someChild, width - padding * 2, height / 3 - padding * 2); setPositionChild(_someChild, x, y); y += _someChild.getHeight() + padding; // Calculate where to start drawing next. /* ... snipped ... */ } As you can see, positioning elements on a screen is a nightmare due to the tedium. I have investigated other GUI frameworks but, for a variety of reasons, it is difficult to find one that suites our purposes. One potential solution that came to me is to create a GUI framework who's API resembles HTML/CSS. This would allow for things like padding, margins, borders and colours to be handled through a sort of CSS API while the content would be organized using the HTML part of the API. It might look something like this: public class OptionsScreen extends Document { public OptionsScreen() { // You would set the style (like CSS style) through the constructor. Div content = new Div(new Style(new Padding(5), Color.BLACK)); // Then build up a tree of elements which can each have their own style's. // Each element knows how to draw itself, but it doesn't have to worry about // manually handling things like padding. // content.addChild(new P("This is a paragraph", new Style(new Padding(), Color.RED))); Ul list = new Ul(); list.addChild(new Li("item 1")); list.addChild(new Li("item 2")); content.addChild(list); addChild(content); } } I can imagine this making it easier to customize the UI of our app (which is very important) with different fonts, colours and layouts. Does this idea belong on The Daily WTF or do you think there is some promise?

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  • PHP running as a FastCGI application (php-cgi) - how to issue concurrent requests?

    - by Sbm007
    Some background information: I'm writing my own webserver in Java and a couple of days ago I asked on SO how exactly Apache interfaces with PHP, so I can implement PHP support. I learnt that FastCGI is the best approach (since mod_php is not an option). So I have looked at the FastCGI protocol specification and have managed to write a working FastCGI wrapper for my server. I have tested phpinfo() and it works, in fact all PHP functions seem to work just fine (posting data, sessions, date/time, etc etc). My webserver is able to serve requests concurrently (ie user1 can retrieve file1.html at the same time as user2 requesting some_large_binary_file.zip), it does this by spawning a new Java thread for each user request (terminating when completed or user connection with client is cancelled). However, it cannot deal with 2 (or more) FastCGI requests at the same time. What it does is, it queues them up, so when request 1 is completed immediately thereafter it starts processing request 2. I tested this with 2 PHP pages, one contains sleep(10) and the other phpinfo(). How would I go about dealing with multiple requests as I know it can be done (PHP under IIS runs as FastCGI and it can deal with multiple requests just fine). Some more info: I am coding under windows and my batch file used to execute php-cgi.exe contains: set PHP_FCGI_CHILDREN=8 set PHP_FCGI_MAX_REQUESTS=500 php-cgi.exe -b 9000 But it does not spawn 8 children, the service simply terminates after 500 requests. I have done research and from Wikipedia: Processing of multiple requests simultaneously is achieved either by using a single connection with internal multiplexing (ie. multiple requests over a single connection) and/or by using multiple connections Now clearly the multiple connections isn't working for me, as everytime a client requests something that involves FastCGI it creates a new socket to the FastCGI application, but it does not work concurrently (it queues them up instead). I know that internal multiplexing of FastCGI requests under the same connection is accomplished by issuing each unique FastCGI request with a different request ID. (also see the last 3 paragraphs of 'The Communication Protocol' heading in this article). I have not tested this, but how would I go about implementing that? I take it I need some kind of FastCGI Java thread which contains a Map of some sort and a static function which I can use to add requests to. Then in the Thread's run() function it would have a while loop and for every cycle it would check whether the Map contains new requests, if so it would assign them a request ID and write them to the FastCGI stream. And then wait for input etc etc, As you can see this becomes too complicated. Does anyone know the correct way of doing this? Or any thoughts at all? Thanks very much. Note, if required I can supply the code for my FastCGI wrapper.

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  • Sliding panel in the middle of the page. Z-index given not working

    - by Nehal Rupani
    Hi all, I am implementing sliding panel element but problem is when i slide out other div element is floating down. I guess and tried to give z-index to element which i am sliding but it doesn't seems to work. Let me put code for both div. <div class="vrcontrol"> <div class="slide-out-div"> <a class="handle" href="http://link-for-non-js-users.html">Content</a> <h3>Contact me</h3> <p>Thanks for checking out my jQuery plugin, I hope you find this useful. </p> <p>This can be a form to submit feedback, or contact info</p> </div> This is div which i am sliding in and out and beneath is code of effective div. <div class="askform"> <p class="titletext">Ask an Expert Trade Forum</p> <p class="detailtext">WD-40’s leading source for DIY tips and tricks.</p> <span> <form id="askform" name="askform" action="" method="post"> <span class="left"><input name="input" type="text" class="askinputbox"/></span><span class="marginleft"><input type="image" src="images/search_icon.gif" /></span> </form> </span> <div class="followus"> <span class="followtext">Follow us on</span><span class="right"><img src="images/bookmark.jpg" width="121" height="45" alt="Bookmark" /></span> </div> </div> Sliding div is in left portion of the page and effective div is in right portion of the page. I guess something with z-index, positioning element and overflow properties will do something.

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  • Cross-site request forgery protections: Where do I put all these lines?

    - by brilliant
    Hello, I was looking for a python code that would be able to log in from "Google App Engine" to some of my accounts on some websites (like yahoo or eBay) and was given this code: import urllib, urllib2, cookielib url = "https://login.yahoo.com/config/login?" form_data = {'login' : 'my-login-here', 'passwd' : 'my-password-here'} jar = cookielib.CookieJar() opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(jar)) form_data = urllib.urlencode(form_data) # data returned from this pages contains redirection resp = opener.open(url, form_data) # yahoo redirects to http://my.yahoo.com, so lets go there instead resp = opener.open('http://mail.yahoo.com') print resp.read() Unfortunately, this code didn't work, so I asked another question here and one supporter among other things said this: "You send MD5 hash and not plain password. Also you'd have to play along with all kinds of CSRF protections etc. that they're implementing. Look: <input type="hidden" name=".tries" value="1"> <input type="hidden" name=".src" value="ym"> <input type="hidden" name=".md5" value=""> <input type="hidden" name=".hash" value=""> <input type="hidden" name=".js" value=""> <input type="hidden" name=".last" value=""> <input type="hidden" name="promo" value=""> <input type="hidden" name=".intl" value="us"> <input type="hidden" name=".bypass" value=""> <input type="hidden" name=".partner" value=""> <input type="hidden" name=".u" value="bd5tdpd5rf2pg"> <input type="hidden" name=".v" value="0"> <input type="hidden" name=".challenge" value="5qUiIPGVFzRZ2BHhvtdGXoehfiOj"> <input type="hidden" name=".yplus" value=""> <input type="hidden" name=".emailCode" value=""> <input type="hidden" name="pkg" value=""> <input type="hidden" name="stepid" value=""> <input type="hidden" name=".ev" value=""> <input type="hidden" name="hasMsgr" value="0"> <input type="hidden" name=".chkP" value="Y"> <input type="hidden" name=".done" value="http://mail.yahoo.com"> <input type="hidden" name=".pd" value="ym_ver=0&c=&ivt=&sg="> I am not quite sure where he got all these lines from and where in my code I am supposed to add them. Do You have any idea? I know I was supposed to ask him this question first, and I did, but he never returned, so I decided to ask a separate question here.

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  • Using JSON Data to Populate a Google Map with Database Objects

    - by MikeH
    I'm revising this question after reading the resources mentioned in the original answers and working through implementing it. I'm using the google maps api to integrate a map into my Rails site. I have a markets model with the following columns: ID, name, address, lat, lng. On my markets/index view, I want to populate a map with all the markets in my markets table. I'm trying to output @markets as json data, and that's where I'm running into problems. I have the basic map displaying, but right now it's just a blank map. I'm following the tutorials very closely, but I can't get the markers to generate dynamically from the json. Any help is much appreciated! Here's my setup: Markets Controller: def index @markets = Market.filter_city(params[:filter]) respond_to do |format| format.html # index.html.erb format.json { render :json => @market} format.xml { render :xml => @market } end end Markets/index view: <head> <script type="text/javascript" src="http://www.google.com/jsapi?key=GOOGLE KEY REDACTED, BUT IT'S THERE" > </script> <script type="text/javascript"> var markets = <%= @markets.to_json %>; </script> <script type="text/javascript" charset="utf-8"> google.load("maps", "2.x"); google.load("jquery", "1.3.2"); </script> </head> <body> <div id="map" style="width:400px; height:300px;"></div> </body> Public/javascripts/application.js: function initialize() { if (GBrowserIsCompatible() && typeof markets != 'undefined') { var map = new GMap2(document.getElementById("map")); map.setCenter(new GLatLng(40.7371, -73.9903), 13); map.addControl(new GLargeMapControl()); function createMarker(latlng, market) { var marker = new GMarker(latlng); var html="<strong>"+market.name+"</strong><br />"+market.address; GEvent.addListener(marker,"click", function() { map.openInfoWindowHtml(latlng, html); }); return marker; } var bounds = new GLatLngBounds; for (var i = 0; i < markets.length; i++) { var latlng=new GLatLng(markets[i].lat,markets[i].lng) bounds.extend(latlng); map.addOverlay(createMarker(latlng, markets[i])); } } } window.onload=initialize; window.onunload=GUnload;

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  • Feedback on Optimizing C# NET Code Block

    - by Brett Powell
    I just spent quite a few hours reading up on TCP servers and my desired protocol I was trying to implement, and finally got everything working great. I noticed the code looks like absolute bollocks (is the the correct usage? Im not a brit) and would like some feedback on optimizing it, mostly for reuse and readability. The packet formats are always int, int, int, string, string. try { BinaryReader reader = new BinaryReader(clientStream); int packetsize = reader.ReadInt32(); int requestid = reader.ReadInt32(); int serverdata = reader.ReadInt32(); Console.WriteLine("Packet Size: {0} RequestID: {1} ServerData: {2}", packetsize, requestid, serverdata); List<byte> str = new List<byte>(); byte nextByte = reader.ReadByte(); while (nextByte != 0) { str.Add(nextByte); nextByte = reader.ReadByte(); } // Password Sent to be Authenticated string string1 = Encoding.UTF8.GetString(str.ToArray()); str.Clear(); nextByte = reader.ReadByte(); while (nextByte != 0) { str.Add(nextByte); nextByte = reader.ReadByte(); } // NULL string string string2 = Encoding.UTF8.GetString(str.ToArray()); Console.WriteLine("String1: {0} String2: {1}", string1, string2); // Reply to Authentication Request MemoryStream stream = new MemoryStream(); BinaryWriter writer = new BinaryWriter(stream); writer.Write((int)(1)); // Packet Size writer.Write((int)(requestid)); // Mirror RequestID if Authenticated, -1 if Failed byte[] buffer = stream.ToArray(); clientStream.Write(buffer, 0, buffer.Length); clientStream.Flush(); } I am going to be dealing with other packet types as well that are formatted the same (int/int/int/str/str), but different values. I could probably create a packet class, but this is a bit outside my scope of knowledge for how to apply it to this scenario. If it makes any difference, this is the Protocol I am implementing. http://developer.valvesoftware.com/wiki/Source_RCON_Protocol

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  • c++ templates: problem with member specialization

    - by ChAoS
    I am attempting to create a template "AutoClass" that create an arbitrary class with an arbitrary set of members, such as: AutoClass<int,int,double,double> a; a.set(1,1); a.set(0,2); a.set(3,99.7); std::cout << "Hello world! " << a.get(0) << " " << a.get(1) << " " << a.get(3) << std::endl; By now I have an AutoClass with a working "set" member: class nothing {}; template < typename T1 = nothing, typename T2 = nothing, typename T3 = nothing, typename T4 = nothing, typename T5 = nothing, typename T6 = nothing> class AutoClass; template <> class AutoClass<nothing, nothing, nothing, nothing, nothing, nothing> { public: template <typename U> void set(int n,U v){} }; template < typename T1, typename T2, typename T3, typename T4, typename T5, typename T6> class AutoClass: AutoClass<T2,T3,T4,T5,T6> { public: T1 V; template <typename U> void set(int n,U v) { if (n <= 0) V = v; else AutoClass<T2,T3,T4,T5,T6>::set(n-1,v); } }; and I started to have problems implementing the corresponding "get". This approach doesn't compile: template < typename T1, typename T2, typename T3, typename T4, typename T5, typename T6> class AutoClass: AutoClass<T2,T3,T4,T5,T6> { public: T1 V; template <typename U> void set(int n,U v) { if (n <= 0) V = v; else AutoClass<T2,T3,T4,T5,T6>::set(n-1,v); } template <typename W> W get(int n) { if (n <= 0) return V; else return AutoClass<T2,T3,T4,T5,T6>::get(n-1); } template <> T1 get(int n) { if (n <= 0) return V; else return AutoClass<T2,T3,T4,T5,T6>::get(n-1); } }; Besides, it seems I need to implement get for the <nothing, nothing, nothing, nothing, nothing, nothing> specialization. Any Idea on how to solve this?

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