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• Making a 64 bit shared library that dynamically links to a 32 bit library on Mac OS X Snow Leopard

  - by carneades

  Update: After some more reading I see that this problem is totally general, you can't mix architectures in the same process, so 64 bit Java cannot dlopen() a 32 bit library like FMOD. Is there any possible workaround for this, keeping in mind I'm writing my own C interface to the FMOD library? I need to make a 64-bit dylib on Max OS X because Java Native Access only likes 64-bit libraries on 64-bit machines. The problem is, my C source code dynamically includes FMOD which on Mac only provides 32-bit dylibs. When I try to compile without the -m32 option (since I must output a 64-bit dylib) I get the following error: gcc -dynamiclib -std=c99 -pedantic -Wall -O3 -fPIC -pthread -o ../bin/libpenntotalrecall_fmod.dylib ../../src/libpenntotalrecall_fmod.c -lfmodex -L../../lib/osx/ ld: warning: in /usr/lib/libfmodex.dylib, missing required architecture x86_64 in file Undefined symbols: "_FMOD_System_CreateSound", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Channel_GetPosition", referenced from: _streamPosition in ccJnlwrd.o "_FMOD_System_Create", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_PlaySound", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Sound_Release", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_Channel_IsPlaying", referenced from: _playbackInProgress in ccJnlwrd.o "_FMOD_System_Update", referenced from: _streamPosition in ccJnlwrd.o _startPlayback in ccJnlwrd.o "_FMOD_Channel_SetPaused", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_Release", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_System_Init", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Channel_SetVolume", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_Close", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_Channel_SetCallback", referenced from: _startPlayback in ccJnlwrd.o ld: symbol(s) not found collect2: ld returned 1 exit status make: *** [all] Error 1 Shouldn't it be possible to get a 64 bit dylib from my source code that dynamically includes 32 bit libraries?!

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• Getter and Setter vs. Builder strategy

  - by Extrakun

  I was reading a JavaWorld's article on Getter and Setter where the basic premise is that getters expose internal content of an object, hence tightening coupling, and go on to provide examples using builder objects. I was rather leery of abolishing getter/setter but on second reading of the article, see to quite like the idea. However, sometimes I just need one cruical element of an entity class, such as the user's id and writing one whole class just to extract that cruical element seems like overkill. It also implies that for different view, a different type of importer/exporter must be implemented (or the whole data of the class to be exported out, thus resulting in waste). Usually I tend towards filtering the result of a getter - for example, if I need to output the price of a product in different currency, I would code it as: return CurrencyOutput::convertTo($product->price(), 'USD'); This is with the understanding that the raw output of a getter is not necessary the final result to be pushed onto a screen or a database. Is getter/setter really as bad as it is protrayed to be? When should one adopt a builder strategy, or a 'get the result and filter it' approach? How do you avoid having a class needing to know about every other objects if you are not using getter/setter?

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• MS Access: Why is ADODB.Recordset.BatchUpdate so much slower than Application.ImportXML?

  - by apenwarr

  I'm trying to run the code below to insert a whole lot of records (from a file with a weird file format) into my Access 2003 database from VBA. After many, many experiments, this code is the fastest I've been able to come up with: it does 10000 records in about 15 seconds on my machine. At least 14.5 of those seconds (ie. almost all the time) is in the single call to UpdateBatch. I've read elsewhere that the JET engine doesn't support UpdateBatch. So maybe there's a better way to do it. Now, I would just think the JET engine is plain slow, but that can't be it. After generating the 'testy' table with the code below, I right clicked it, picked Export, and saved it as XML. Then I right clicked, picked Import, and reloaded the XML. Total time to import the XML file? Less than one second, ie. at least 15x faster. Surely there's an efficient way to insert data into Access that doesn't require writing a temp file? Sub TestBatchUpdate() CurrentDb.Execute "create table testy (x int, y int)" Dim rs As New ADODB.Recordset rs.CursorLocation = adUseServer rs.Open "testy", CurrentProject.AccessConnection, _ adOpenStatic, adLockBatchOptimistic, adCmdTableDirect Dim n, v n = Array(0, 1) v = Array(50, 55) Debug.Print "starting loop", Time For i = 1 To 10000 rs.AddNew n, v Next i Debug.Print "done loop", Time rs.UpdateBatch Debug.Print "done update", Time CurrentDb.Execute "drop table testy" End Sub I would be willing to resort to C/C++ if there's some API that would let me do fast inserts that way. But I can't seem to find it. It can't be that Application.ImportXML is using undocumented APIs, can it?

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• Get ID in GridView

  - by Romil

  Hi, I have One grid say Grid 1 in which there are some columns. There is one view image button, one delete image button and one column which says that color column is Red or Blue. If color column is Red the deleted button is hidden else its shown (Based on user given rights to delete a column or not). Now a user clicks a view button for Red Color Column. If this condition is satisfied, then i want that delete icon should not be present in Grid 2. Grid 2 has 2 columns. One is deleted image button and one is file name (which is uploaded via upload control). So If in Grid One "View Image Button" is clicked for "Red" Column i should be able to hide the delete button from Grid 2. I have tried by writing code in Item command but i am not able to access control of grid2. is this the correct way? Or else suggest me some correct way. Please Make sure that code is compatible with VS 2003. let me know if more inputs are needed. Thanks

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• How to correctly relay TCP traffic between sockets?

  - by flukes1

  I'm trying to write some Python code that will establish an invisible relay between two TCP sockets. My current technique is to set up two threads, each one reading and subsequently writing 1kb of data at a time in a particular direction (i.e. 1 thread for A to B, 1 thread for B to A). This works for some applications and protocols, but it isn't foolproof - sometimes particular applications will behave differently when running through this Python-based relay. Some even crash. I think that this is because when I finish performing a read on socket A, the program running there considers its data to have already arrived at B, when in fact I - the devious man in the middle - have yet to send it to B. In a situation where B isn't ready to receive the data (whereby send() blocks for a while), we are now in a state where A believes it has successfully sent data to B, yet I am still holding the data, waiting for the send() call to execute. I think this is the cause of the difference in behaviour that I've found in some applications, while using my current relaying code. Have I missed something, or does that sound correct? If so, my real question is: is there a way around this problem? Is it possible to only read from socket A when we know that B is ready to receive data? Or is there another technique that I can use to establish a truly 'invisible' two-way relay between [already open & established] TCP sockets?

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• Idiomatic STL: Iterating over a list and inserting elements

  - by mkilling

  I'm writing an algorithm that iterates over a list of points, calculates the distance between them and inserts additional points if the distance is too great. However I seem to be lacking the proper familiarity with STL to come up with an elegant solution. I'm hoping that I can learn something, so I'll just show you my code. You might have some hints for me. for (std::list<PathPoint>::iterator it = ++points_.begin(); it != points_.end(); it++) { Vector curPos = it->getPosition(); Vector prevPos = (--it)->getPosition(); Vector vecFromPrev = curPos - prevPos; float distance = vecFromPrev.abs(); it++; if (distance > MAX_DISTANCE_BETWEEN_POINTS) { int pointsToInsert = (int)(distance / MAX_DISTANCE_BETWEEN_POINTS); Vector curPos = prevPos; for (int i = 0; i < pointsToInsert; i++) { curPos += vecFromPrev / pointsToInsert; it = points_.insert(it, PathPoint(curPos, false)); it++; } } }

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• GWT CssResource Customization

  - by Eric Landry

  I'm writing a GWT widget using UIBinder and MVP. The widget's default styles are defined in TheWidgetView.ui.xml: <ui:style type="com.widgetlib.spinner.display.TheWidgetView.MyStyle"> .textbox { border: 1px solid #red; } .important { font-weight: bold; } </ui:style> The widget's CssResource interface is defined in TheWidgetView.java: public class TheWidgetView extends HorizontalPanel implements TheWidgetPresenter.Display { // ... some code @UiField MyStyle style; public interface MyStyle extends CssResource { String textbox(); String important(); } // ... more code } I'd like the consumer of this widget to be able to customize part of the widget's styles and to have this in their MyExample.ui.xml: <ui:style type="com.consumer.MyExample.MyStyle"> .textbox { border: 2px solid #black; } </ui:style> And this be their MyExample.java: public class MyExample extends Composite { // ... some code @UiField MyStyle style; interface MyStyle extends TheWidgetView.MyStyle{ String textbox(); } // ... more code } Is there a way that my widget can have default styles, but that the consumer of the widget can override one of them? When an interface extends TheWidgetView.MyStyle, the of the widget consumer needs to define all the styles listed in that parent interface. I've seen some widget libraries have the widget's constructor take in a ClientBundle as parameter, which I suppose could apply to CssResource. Although, I'm not sure how I'd pass in this style object in a constructor invoked by UIBinder. Thanks much in advance!

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• PHP unit tests for controller returns no errors and no success message.

  - by Mallika Iyer

  I'm using the zend modular director structure, i.e. application modules users controllers . . lessons reports blog I have a unit test for a controller in 'blog' that goes something like the below section of code: I'm definitely doing something very wrong, or missing something - as when i run the test, i get no error, no success message (that goes usually like ...OK (2 tests, 2 assertions)). I get all the text from layout.phtml, where i have the global site layout. This is my first endeavor writing a unittest for zend-M-V-C structure so probably I'm missing something important? Here goes.... require_once '../../../../public/index.php'; require_once '../../../../application/Bootstrap.php'; require_once '../../../../application/modules/blog/controllers/BrowseController.php'; require_once '../../../TestConfiguration.php'; class Blog_BrowseControllerTest extends Zend_Test_PHPUnit_ControllerTestCase { public function setUp() { $this->bootstrap = array($this, 'appBootstrap'); Blog_BrowseController::setUp(); } public function appBootstrap() { require_once dirname(__FILE__) . '/../../bootstrap.php'; } public function testAction() { $this->dispatch('/'); $this->assertController('browse'); $this->assertAction('index'); } public function tearDown() { $this->resetRequest(); $this->resetResponse(); Blog_BrowseController::tearDown(); } }

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• Multithreading and Interrupts

  - by Nicholas Flynt

  I'm doing some work on the input buffers for my kernel, and I had some questions. On Dual Core machines, I know that more than one "process" can be running simultaneously. What I don't know is how the OS and the individual programs work to protect collisions in data. There are two things I'd like to know on this topic: (1) Where do interrupts occur? Are they guaranteed to occur on one core and not the other, and could this be used to make sure that real-time operations on one core were not interrupted by, say, file IO which could be handled on the other core? (I'd logically assume that the interrupts would happen on the 1st core, but is that always true, and how would you tell? Or perhaps does each core have its own settings for interrupts? Wouldn't that lead to a scenario where each core could react simultaneously to the same interrupt, possibly in different ways?) (2) How does the dual core processor handle opcode memory collision? If one core is reading an address in memory at exactly the same time that another core is writing to that same address in memory, what happens? Is an exception thrown, or is a value read? (I'd assume the write would work either way.) If a value is read, is it guaranteed to be either the old or new value at the time of the collision? I understand that programs should ideally be written to avoid these kinds of complications, but the OS certainly can't expect that, and will need to be able to handle such events without choking on itself.

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• help with Firefox extension

  - by Johnny Grass

  I'm writing a Firefox extension that creates a socket server which will output the active tab's URL when a client makes a connection to it. I have the following code in my javascript file: var serverSocket; function startServer() { var listener = { onSocketAccepted : function(socket, transport) { try { var outputString = gBrowser.currentURI.spec + "\n"; var stream = transport.openOutputStream(0,0,0); stream.write(outputString,outputString.length); stream.close(); } catch(ex2){ dump("::"+ex2); } }, onStopListening : function(socket, status){} }; try { serverSocket = Components.classes["@mozilla.org/network/server-socket;1"] .createInstance(Components.interfaces.nsIServerSocket); serverSocket.init(7055,true,-1); serverSocket.asyncListen(listener); } catch(ex){ dump(ex); } document.getElementById("status").value = "Started"; } startServer(); As it is, it works for multiple tabs in a single window. If I open multiple windows, it ignores the additional windows. I think it is creating a server socket for each window, but since they are using the same port, the additional sockets fail to initialize. I need it to create a server socket when the browser launches and continue running when I close the windows (Mac OS X). As it is, when I close a window but Firefox remains running, the socket closes and I have to restart firefox to get it up an running. How do I go about that?

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• Generate colors between red and green for a power meter?

  - by Simucal

  I'm writing a java game and I want to implement a power meter for how hard you are going to shoot something. I need to write a function that takes a int between 0 - 100, and based on how high that number is, it will return a color between Green (0 on the power scale) and Red (100 on the power scale). Similar to how volume controls work: What operation do I need to do on the Red, Green, and Blue components of a color to generate the colors between Green and Red? So, I could run say, getColor(80) and it will return an orangish color (its values in R, G, B) or getColor(10) which will return a more Green/Yellow rgb value. I know I need to increase components of the R, G, B values for a new color, but I don't know specifically what goes up or down as the colors shift from Green-Red. Progress: I ended up using HSV/HSB color space because I liked the gradiant better (no dark browns in the middle). The function I used was (in java): public Color getColor(double power) { double H = power * 0.4; // Hue (note 0.4 = Green, see huge chart below) double S = 0.9; // Saturation double B = 0.9; // Brightness return Color.getHSBColor((float)H, (float)S, (float)B); } Where "power" is a number between 0.0 and 1.0. 0.0 will return a bright red, 1.0 will return a bright green. Java Hue Chart: Thanks everyone for helping me with this!

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• Uncompress OpenOffice files for better storage in version control

  - by Craig McQueen

  I've heard discussion about how OpenOffice (ODF) files are compressed zip files of XML and other data. So making a tiny change to the file can potentially totally change the data, so delta compression doesn't work well in version control systems. I've done basic testing on an OpenOffice file, unzipping it and then rezipping it with zero compression. I used the Linux zip utility for my testing. OpenOffice will still happily open it. So I'm wondering if it's worth developing a small utility to run on ODF files each time just before I commit to version control. Any thoughts on this idea? Possible better alternatives? Secondly, what would be a good and robust way to implement this little utility? Bash shell that calls zip (probably Linux only)? Python? Any gotchas you can think of? Obviously I don't want to accidentally mangle a file, and there are several ways that could happen. Possible gotchas I can think of: Insufficient disk space Some other permissions issue that prevents writing the file or temporary files ODF document is encrypted (probably should just leave these alone; the encryption probably also causes large file changes and thus prevents efficient delta compression)

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• DataTable vs. Collection in .Net

  - by B Pete

  I am writing a program that needs to read a set of records that describe the register map of a device I need to communicate with. Each record will have a handfull of fields that describe the properties of each register. I don't really need to edit or modify the data in my VB or C# program, though I would like to be able to display the data on a grid. I would like to store the data in a CSV file, or perhaps an XML file. I need to enable users to edit the data off-line, preferably in excel. I am considering using a DataTable or a Collection of "Register" objects (which I would define). I prototyped a DataTable, and found I can read/write XML easily using the built in methods and I can easily bind to a DataGridView. I was not able to find a way to retreive info on a single register without using a query that returns a collection of rows, even though I defined a unique primaty key column. The syntax to get a value from a column is also complex, though I could be missing something on both counts. I'm tempted to use a collection of "Register" objects that I can access via a unique key. It would be a little more coding up front, but seems like a cleaner solution overall. I should still be able to use LINQ to dataset to query subsets of registers when I need them, but would also be able to grab a single field using a the key value, something like this: Registers(keyValue).fieldName). Which would be a cleaner approach to the problem? Is there a way to read/write XML into a Collection without needing custom code? Could this be accomplished using String for a key?

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• D callbacks in C functions

  - by Caspin

  I am writing D2 bindings for Lua. This is in one of the Lua header files. typedef int (*lua_CFunction) (lua_State *L); I assume the equivalent D2 statement would be: extern(C) alias int function( lua_State* L ) lua_CFunction; Lua also provides an api function: void lua_pushcfunction( lua_State* L, string name, lua_CFunction func ); If I want to push a D2 function does it have to be extern(C) or can I just use the function? int dfunc( lua_State* L ) { std.stdio.writeln("dfunc"); } extern(C) int cfunc( lua_State* L ) { std.stdio.writeln("cfunc"); } lua_State* L = lua_newstate(); lua_pushcfunction(L, "cfunc", &cfunc); //This will definitely work. lua_pushcfunction(L, "dfunc", &dfunc); //Will this work? If I can only use cfunc, why? I don't need to do anything like that in C++. I can just pass the address of a C++ function to C and everything just works.

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• Multiple Application Support Directories for iPhone Simulator?

  - by Alex G

  I am developing an iPhone app with someone else. The app works fine for me, but he is running into a bug. We think this bug is related to the fact that he is getting multiple Application directories for this same app. In my ~/Library/Application Support/iPhone Simulator/User/Applications, I only have one folder at all times. He says that he will get 3 or 4 directories when he is only working on this one app. We think this is our problem because our bug has to do with displaying images that are stored in the app's Documents folder. Does anyone know why he is ending up with multiple directories or how to stop it? Edit: Here is the code for writing the image to a file: NSData *image = [NSData dataWithContentsOfURL:[NSURL URLWithString:[currentArticle articleImage]]]; NSArray *array = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *imagePath = [array objectAtIndex:0]; NSFileManager *NSFM = [NSFileManager defaultManager]; BOOL isDir = YES; if(![NSFM fileExistsAtPath:imagePath isDirectory:&isDir]) if(![NSFM createDirectoryAtPath:imagePath attributes:nil]) NSLog(@"error"); imagePath = [imagePath stringByAppendingFormat:@"/images"]; if(![NSFM fileExistsAtPath:imagePath isDirectory:&isDir]) if(![NSFM createDirectoryAtPath:imagePath attributes:nil]) NSLog(@"error"); imagePath = [imagePath stringByAppendingFormat:@"/%@.jpg", [currentArticle uniqueID]]; [image writeToFile:imagePath atomically:NO]; And here is the code for getting the path when I need the image: - (NSString *)imagePath { NSArray *array = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *imagePath = [array objectAtIndex:0]; return [imagePath stringByAppendingFormat:@"/images/%@.jpg", [self uniqueID]]; } The app works great for me, but my partner says that the images don't show up intermittently, and he notices that he gets multiple directories in his Applications folder.

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• How to architect Rails site that can be edited while running?

  - by Chris Kimpton

  Hi, I am writing a Rails app that "scrapes/navigates" some other websites and webservices for content. I am using Mechanize and Savon to do the heavylifting. But given the dynamic nature of the web, I'd like to make my calls to these editable by the admin users of the site - rather than requiring me to release a new version of the site. The actual scraping thread happens async to the website, using the daemons gem. My requirements are: Thinking that the scraping/webservice calling code is quite simple, the easiest route is to make the whole class editable by the admins. Keep a history of the scraping code - so that we can fairly easily revert if we introduce a problem. Initially use the code from the file system, but as soon as thats been edited and stored somewhere, to use that code instead. I am thinking my options are: Store the code in the db (with a history table for the old versions) Store the code in a private git repo somewhere and access that for the history/latest versions. I am thinking the git route might be easiest, given its raison d'etre is to track file history... But perhaps there is a gem/plugin that does all this for me, out of the box? Thanks in advance for any tips/advice. ~chris

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• SQL Server 2008: Comparing similar records - Need to still display an ID for a record when the JOIN has no matches

  - by aleppke

  I'm writing a SQL Server 2008 report that will compare genetic test results for animals. A genetic test consists of an animalId, a gene and a result. Not all animals will have the same genes tested but I need to be able to display the results side-by-side for a given set of animals and only include the genes that are present for at least one of the selected animals. My TestResult table has the following data in it: animalId gene result 1 a CC 1 b CT 1 d TT 2 a CT 2 b CT 2 c TT 3 a CT 3 b TT 3 c CC 3 d CC 3 e TT I need to generate a result set that looks like the following. Note that Animal 3 is not being displayed (user doesn't want to see its results) and neither are results for Gene "e" since neither Animal 1 nor Animal 2 have a result for that gene: SireID SireResult CalfID CalfResult Gene 1 CC 2 CT a 1 CT 2 CT b 1 NULL 2 TT c 1 TT 2 NULL d But I can only manage to get this: SireID SireResult CalfID CalfResult Gene 1 CC 2 CT a 1 CT 2 CT b NULL NULL 2 TT c 1 TT NULL NULL d This is the query I'm using. SELECT sire.animalId AS 'SireID' ,sire.result AS 'SireResult' ,calf.animalId AS 'CalfID' ,calf.result AS 'CalfResult' ,sire.gene AS 'Gene' FROM (SELECT s.animalId ,s.result ,m1.gene FROM (SELECT [animalId ] ,result ,gene FROM TestResult WHERE animalId IN (1)) s FULL JOIN (SELECT DISTINCT gene FROM TestResult WHERE animalId IN (1, 2)) m1 ON s.marker = m1.marker) sire FULL JOIN (SELECT c.animalId ,c.result ,m2.gene FROM (SELECT animalId ,result ,gene FROM TestResult WHERE animalId IN (2)) c FULL JOIN (SELECT DISTINCT gene FROM TestResult WHERE animalId IN (1, 2)) m2 ON c.gene = m2.gene) calf ON sire.gene = calf.gene How do I get the SireIDs and CalfIDs to display their values when they don't have a record associated with a particular Gene? I was thinking of using COALESCE but I can't figure out how to specify the correct animalId to pass in. Any help would be appreciated.

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• Visual Studio Designer looses / ignores data

  - by Kempeth

  I'm writing my own control - a datagridviewcolumn that displays integer values as texts like the comboboxcolumn can but without showing the combobox unless the cell is edited. I'm mostly there but I have problems with the databinding. I managed to get the necessary properties to appear in the designer but every time I set the datasource and close the editor the changes are dropped. When I assign the same datasource later in code it works like a charm, I just would prefer not having to do that... public class DataGridViewLookupColumn : DataGridViewColumn { private DataGridViewLookupCell template; private Object datasource = null; private String displaymember = String.Empty; private String valuemember = String.Empty; private BindingSource bindingsource = new BindingSource(); public DataGridViewLookupColumn() : base() { this.template = new DataGridViewLookupCell(); } public override DataGridViewCell CellTemplate { get { return this.template; } set { } } [Category("Data")] [ DefaultValue(null), RefreshProperties(RefreshProperties.Repaint), AttributeProvider(typeof(IListSource)), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible), ] public object DataSource { get { return this.bindingsource.DataSource; //return this.datasource; } set { this.bindingsource.DataSource = value; this.bindingsource.EndEdit(); } } [Category("Data")] [ DefaultValue(""), TypeConverterAttribute("System.Windows.Forms.Design.DataMemberFieldConverter, System.Design"), Editor("System.Windows.Forms.Design.DataMemberFieldEditor, System.Design", typeof(System.Drawing.Design.UITypeEditor)), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible), ] public String DisplayMember { get { return this.displaymember; } set { this.displaymember = value; } } [Category("Data")] [ DefaultValue(""), TypeConverterAttribute("System.Windows.Forms.Design.DataMemberFieldConverter, System.Design"), Editor("System.Windows.Forms.Design.DataMemberFieldEditor, System.Design", typeof(System.Drawing.Design.UITypeEditor)), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible), ] public String ValueMember { get { return this.valuemember; } set { this.valuemember = value; } } } EDIT: I experimenting I just found out that that original DataGridViewComboBoxColumn can be made to behave exactly like I wanted to. By setting the DisplayStyle to Nothing the combobox control is only shown in edit mode.

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• Simple in-place discrete fourier transform ( DFT )

  - by Adam

  I'm writing a very simple in-place DFT. I am using the formula shown here: http://en.wikipedia.org/wiki/Discrete_Fourier_transform#Definition along with Euler's formula to avoid having to use a complex number class just for this. So far I have this: private void fft(double[] data) { double[] real = new double[256]; double[] imag = new double[256]; double pi_div_128 = -1 * Math.PI / 128; for (int k = 0; k < 256; k++) { for (int n = 0; n < 256; n++) { real[k] += data[k] * Math.Cos(pi_div_128 * k * n); imag[k] += data[k] * Math.Sin(pi_div_128 * k * n); } data[k] = Math.Sqrt(real[k] * real[k] + imag[k] * imag[k]); } } But the Math.Cos and Math.Sin terms eventually go both positive and negative, so as I'm adding those terms multiplied with data[k], they cancel out and I just get some obscenely small value. I see how it is happening, but I can't make sense of how my code is perhaps mis-representing the mathematics. Any help is appreciated. FYI, I do have to write my own, I realize I can get off-the shelf FFT's.

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• Are there any ASP.NET MVC subscription-based starter kits or examples?

  - by Wayne M

  Basically something that handles the low-level "plumbing" code for a subscription-based service. I see a lot of things dealing with basic membership, but nothing that handles the subscription aspect (recurring billing, automated jobs for setting up billing, notification for billing, etc). This might be the one thing that keeps me from using ASP.NET MVC for my SaaS idea, since it would take a fair amount of development time to write my own; if I go with my other option, Ruby on Rails, I can buy a kit that does all of this for $250. I haven't found anything even remotely close to this for .NET - all of the SaaS sample apps I've seen are more like StackOverflow et all where you have one site that multiple people log on to, not the web application model where you have subscribers who are billed monthly, each of whom has users and other entities (e.g. Customers, Tasks, etc) for their own site. Is there anything similar for ASP.NET, or some kind of guidelines for writing my own if I have to, so I don't waste too much time? As a startup that means that I'm doing all the coding myself. I've found this, but it seems to only be for billing and didn't seem to have much (any?) documentation on exactly how to set it up.

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• Use of const double for intermediate results

  - by Arne

  Hi, I a writing a Simulation program and wondering if the use of const double is of any use when storing intermediate results. Consider this snippet: double DoSomeCalculation(const AcModel &model) { (...) const double V = model.GetVelocity(); const double m = model.GetMass(); const double cos_gamma = cos(model.GetFlightPathAngleRad()); (...) return m*V*cos_gamma*Chi_dot; } Note that the sample is there only to illustrate -- it might not make to much sense from the engineering side of things. The motivation of storing for example cos_gamma in a variable is that this cosine is used many time in other expressions covered by (...) and I feel that the code gets more readable when using cos_gamma rather than cos(model.GetFlightPathAngleRad()) in various expressions. Now the actual is question is this: since I expect the cosine to be the same througout the code section and I actually created the thing only as a placeholder and for convenience I tend to declare it const. Is there a etablished opinion on wether this is good or bad practive or whether it might bite me in the end? Does a compiler make any use of this additional information or am I actually hindering the compiler from performing useful optimizations? Arne

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• How to install DBD::mysql on OS X Server 10.6?

  - by Zoran Simic

  Trying to install DBD::mysql on OS X Server 10.6 (mac mini server). But I'm missing the mysql headers apparently. Since mysql is already part of OS X Server 10.6, I would like to NOT install anything else (no fink or darwin ports installs), just whatever's needed to get DBD::mysql installed and working. Do you know how I could do that? Do I have to install the headers somewhere? And if so, where? (again: I don't want to install another version of mysql on the box, want to use the version it came with). Is there a way to install DBD::mysql without compiling any C files? This is the error I get (the actual error is much longer, but these are the most meaningful bits, this is the first error reported). Checking if your kit is complete... Looks good Unrecognized argument in LIBS ignored: '-pipe' Note (probably harmless): No library found for -lmysqlclient Multiple copies of Driver.xst found in: /Library/Perl/5.10.0/darwin-thread-multi-2level/auto/DBI/ /System/Library/Perl/Extras/5.10.0/darwin-thread-multi-2level/auto/DBI/ at Makefile.PL line 907 Using DBI 1.611 (for perl 5.010000 on darwin-thread-multi-2level) installed in /Library/Perl/5.10.0/darwin-thread-multi-2level/auto/DBI/ Writing Makefile for DBD::mysql cp lib/DBD/mysql.pm blib/lib/DBD/mysql.pm cp lib/DBD/mysql/GetInfo.pm blib/lib/DBD/mysql/GetInfo.pm cp lib/DBD/mysql/INSTALL.pod blib/lib/DBD/mysql/INSTALL.pod cp lib/Bundle/DBD/mysql.pm blib/lib/Bundle/DBD/mysql.pm gcc-4.2 -c -I/Library/Perl/5.10.0/darwin-thread-multi-2level/auto/DBI -I/usr/include -fno-omit-frame-pointer -pipe -D_P1003_1B_VISIBLE -DSIGNAL_WITH_VIO_CLOSE -DSIGNALS_DONT_BREAK_READ -DIGNORE_SIGHUP_SIGQUIT -DDBD_MYSQL_INSERT_ID_IS_GOOD -g -arch x86_64 -arch i386 -arch ppc -g -pipe -fno-common -DPERL_DARWIN -fno-strict-aliasing -I/usr/local/include -Os -DVERSION=\"4.014\" -DXS_VERSION=\"4.014\" "-I/System/Library/Perl/5.10.0/darwin-thread-multi-2level/CORE" dbdimp.c In file included from dbdimp.c:20: dbdimp.h:22:49: error: mysql.h: No such file or directory dbdimp.h:23:45: error: mysqld_error.h: No such file or directory dbdimp.h:25:49: error: errmsg.h: No such file or directory

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• CssClass and default images in ServerContol

  - by Jeff Dege

  I'm writing a ServerControl in ASP.NET 3.5, and I'm exposing CssClass, so the user can manipulate the visual appearance of the control. My problem is that I want to establish reasonable defaults, so that the user doesn't have to configure CSS unless he wants to change the defaults. My specific problem is that my control is emitting html divs, that need to display background images. I want the user to be able to specify a different image in CSS, but I want to display a default background image, and I can't make that work. The entire server control is emitted as a div, with a class name set to the value the user provided in CssClass. The div that needs the background image is enclosed within this outer div, with a class name of its own. I am currently setting the background image in CSS on the page that contains the control: <style type="text/css"> .cssClass .innerDiv { background-image: url("http://...."); } </style> With this the proper image is drawn. But if it's not there, no image is drawn. What I want is for the ServerControl to emit some CSS that will define these image urls, that would be over-ridden by any css that was added by the user, and for that default CSS to include URLs to images embedded in the ServerControl's assembly. And I'm not sure of how to do either. Nor, for that matter, am I sure this is the best approach. Any ideas?

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• My First F# program

  - by sudaly

  Hi I just finish writing my first F# program. Functionality wise the code works the way I wanted, but not sure if the code is efficient. I would much appreciate if someone could review the code for me and point out the areas where the code can be improved. Thanks Sudaly open System open System.IO open System.IO.Pipes open System.Text open System.Collections.Generic open System.Runtime.Serialization [<DataContract>] type Quote = { [<field: DataMember(Name="securityIdentifier") >] RicCode:string [<field: DataMember(Name="madeOn") >] MadeOn:DateTime [<field: DataMember(Name="closePrice") >] Price:float } let m_cache = new Dictionary<string, Quote>() let ParseQuoteString (quoteString:string) = let data = Encoding.Unicode.GetBytes(quoteString) let stream = new MemoryStream() stream.Write(data, 0, data.Length); stream.Position <- 0L let ser = Json.DataContractJsonSerializer(typeof<Quote array>) let results:Quote array = ser.ReadObject(stream) :?> Quote array results let RefreshCache quoteList = m_cache.Clear() quoteList |> Array.iter(fun result->m_cache.Add(result.RicCode, result)) let EstablishConnection() = let pipeServer = new NamedPipeServerStream("testpipe", PipeDirection.InOut, 4) let mutable sr = null printfn "[F#] NamedPipeServerStream thread created, Wait for a client to connect" pipeServer.WaitForConnection() printfn "[F#] Client connected." try // Stream for the request. sr <- new StreamReader(pipeServer) with | _ as e -> printfn "[F#]ERROR: %s" e.Message sr while true do let sr = EstablishConnection() // Read request from the stream. printfn "[F#] Ready to Receive data" sr.ReadLine() |> ParseQuoteString |> RefreshCache printfn "[F#]Quot Size, %d" m_cache.Count let quot = m_cache.["MSFT.OQ"] printfn "[F#]RIC: %s" quot.RicCode printfn "[F#]MadeOn: %s" (String.Format("{0:T}",quot.MadeOn)) printfn "[F#]Price: %f" quot.Price

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• Efficient cron job utilizing Zend_Mail_Storage_Imap.

  - by fireeyedboy

  I'm new to the IMAP protocol and Zend_Mail_Storage and I'm writing a small php script for a cron job that should regularly poll an IMAP account and check for new messages, and send an e-mail if new messages have arrived. As you can imagine, I want to only poll the IMAP account for relevant messages, and I only want to send a new e-mail if new messages have arrived since the last polled new message. So I thought of keeping track of the last message I polled with some unique identifier for a message. But I'm a bit uncertain about whether the methods I want to utilize for this do what I expect them to do though. So my questions are: Does the iterator position of Zend_Mail_Storage_Imap actually resemble some IMAP unique identifier for messages, or is it simply only and internal position of Zend_Mail_Storage_Abstract? For instance, if I tell it to seek() to message 5 (which I stored from an earlier session) will it indeed seek to the appropriate message on the IMAP server, even if for instance messages have been deleted since last session? Would keeping track of this latest polled message id in a file suffice for a cron job that, say, polls the account every 5 or 10 minutes? Or is this too naive, and should I be using a database for instance. Or is there maybe a much easier way to keep track of such state with Zend_Mail_Storage_Abstract? Also, do I need to poll every IMAP folder? Or is everything accumulated when I poll INBOX? If you could shed some light on any of these matters, I'ld appreciate it. Thanks in advance.

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