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• Interactive World Map, highlight countries on mouseover

  - by BrenGG

  I need to create an interactive world map on the front page of a site, the view portal will be about 650x200 pixels. The interactivity would include the following, mouse-over a country would highlight (the countries are will literally be filled with "red" for example) that country and display the countries' name (preferably text in a div), I will also be linking the highlighting event with a that will highlight a country when selected. I am having a difficult time finding a suitable solution, I refuse to use or learn a proprietry technology such as flash so it is not an option. I created a simple mockup using openlayers and a custom map image but the countries' markers load too slowly in IE6. Also svg seems too large, as I tried to use RaphaelJS, but abondoned it when I realised the world map data is 1.2mb which is totally un acceptable for the front page of a site.. I am really at a loss on how I am going to do this, my last resort is to manually create 250+ (however many countries there are) pngs and apply mouseover events to hotspots in the image... but this is probably going to be a dead end too.. desperately seeking a solution, any helpful comments will be appreciated!

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• JNI Stream binary data from C++ to Java

  - by Cliff

  I need help passing binary data into Java. I'm trying to use jbytearray but when the data gets into Java it appears corrupt. Can somebody give me a hand? Here's a snip of some example code. First the native C++ side: printf("Building audio array copy\n"); jbyteArray rawAudioCopy = env-NewByteArray(10); jbyte toCopy[10]; printf("Filling audio array copy\n"); char theBytes[10] = {0,1,2,3,4,5,6,7,8,9}; for (int i = 0; i < sizeof(theBytes); i++) { toCopy[i] = theBytes[i]; } env->SetByteArrayRegion(rawAudioCopy,0,10,toCopy); printf("Finding object callback\n"); jmethodID aMethodId = env->GetMethodID(env->GetObjectClass(obj),"handleAudio","([B)V"); if(0==aMethodId) throw MyRuntimeException("Method not found error",99); printf("Invoking the callback\n"); env->CallVoidMethod(obj,aMethodId, &rawAudioCopy); and then the Java callback method: public void handleAudio(byte[] audio){ System.out.println("Audio supplied to Java [" + audio.length + "] bytes"); byte[] expectedAudio = {0,1,2,3,4,5,6,7,8,9}; for (int i = 0; i < audio.length; i++) { if(audio[i]!= expectedAudio[i]) System.err.println("Expected byte " + expectedAudio[i] + " at byte " + i + " but got byte " + audio[i]); else System.out.print('.'); } System.out.println("Audio passed back accordingly!"); } I get the following output when the callback is invoked: library loaded! Audio supplied to Java [-2019659176] bytes Audio passed back accordingly!

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• text to image conversion with JSON response

  - by ruhit

  i have made an application to convert text into image and it working out fine,now i am using JSON for conversion,it also working but except only two fields.....why i dont know, my codes are given below...please help me , is there any better way? // img.html excoflare enter your text here: Font Size:          Color:               Font:                 Height:              Width:                                            img.php require_once 'JSON/JSON.php'; header('Content-type: application/json'); header ("Content-type: image/png"); $text =$_REQUEST['text']; $text=json_encode($text); $path="C:\wamp\www\image"; $height=$_REQUEST['height']; $width=$_REQUEST['width']; define("WIDTH", $width); json_encode(WIDTH); define("HEIGHT", $height); json_encode(HEIGHT); $img = imagecreate(WIDTH, HEIGHT); imagesavealpha($img, true); $trans_colour = imagecolorallocatealpha($img, 0, 0, 0, 127); imagefill($img, 0, 0, $trans_colour); $getcolor=$_REQUEST['color']; switch($getcolor) { case 'red': $red = imagecolorallocate($img, 223, 14, 91); $color=json_encode($red); break; case 'white': $white = imagecolorallocate($img, 255, 255, 255); $color=json_encode($white); break; case 'black': $black = imagecolorallocate($img, 0,0,0); $color=json_encode($black); break; case 'grey': $grey = imagecolorallocate($img, 128, 128, 128); $color=json_encode($grey); break; // default: // break; } //$background_color = imagecolorallocate ($img, 25, 25, 25); $font = $_REQUEST['font']; //$font=json_encode($font); $fontsize =$_REQUEST['size']; //$fontsize=json_encode($fontsize); imagettftext($img, $fontsize, 0, 20, 20, $color, $font, $text); //Create image imagepng($img); imagepng($img,"$path/img.png"); //destroy image ImageDestroy($img); //header ('Content-type: image/png'); ? Thanks in advance..

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• SQL Query to return maximums over decades

  - by Abraham Lincoln

  My question is the following. I have a baseball database, and in that baseball database there is a master table which lists every player that has ever played. There is also a batting table, which tracks every players' batting statistics. I created a view to join those two together; hence the masterplusbatting table. CREATE TABLE `Master` ( `lahmanID` int(9) NOT NULL auto_increment, `playerID` varchar(10) NOT NULL default '', `nameFirst` varchar(50) default NULL, `nameLast` varchar(50) NOT NULL default '', PRIMARY KEY (`lahmanID`), KEY `playerID` (`playerID`), ) ENGINE=MyISAM AUTO_INCREMENT=18968 DEFAULT CHARSET=latin1; CREATE TABLE `Batting` ( `playerID` varchar(9) NOT NULL default '', `yearID` smallint(4) unsigned NOT NULL default '0', `teamID` char(3) NOT NULL default '', `lgID` char(2) NOT NULL default '', `HR` smallint(3) unsigned default NULL, PRIMARY KEY (`playerID`,`yearID`,`stint`), KEY `playerID` (`playerID`), KEY `team` (`teamID`,`yearID`,`lgID`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; Anyway, my first query involved finding the most home runs hit every year since baseball began, including ties. The query to do that is the following.... select f.yearID, f.nameFirst, f.nameLast, f.HR from ( select yearID, max(HR) as HOMERS from masterplusbatting group by yearID )as x inner join masterplusbatting as f on f.yearID = x.yearId and f.HR = x.HOMERS This worked great. However, I now want to find the highest HR hitter in each decade since baseball began. Here is what I tried. select f.yearID, truncate(f.yearid/10,0) as decade,f.nameFirst, f.nameLast, f.HR from ( select yearID, max(HR) as HOMERS from masterplusbatting group by yearID )as x inner join masterplusbatting as f on f.yearID = x.yearId and f.HR = x.HOMERS group by decade You can see that I truncated the yearID in order to get 187, 188, 189 etc instead of 1897, 1885,. I then grouped by the decade, thinking that it would give me the highest per decade, but it is not returning the correct values. For example, it's giving me Adrian Beltre with 48 HR's in 2004 but everyone knows that Barry Bonds hit 73 HR in 2001. Can anyone give me some pointers?

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• What is an elegant way to solve this max and min problem in Ruby or Python?

  - by ????

  The following can be done by step by step, somewhat clumsy way, but I wonder if there are elegant method to do it. There is a page: http://www.mariowiki.com/Mario_Kart_Wii, where there are 2 tables... there is Mario - 6 2 2 3 - - Luigi 2 6 - - - - - Diddy Kong - - 3 - 3 - 5 [...] The name "Mario", etc are the Mario Kart Wii character names. The numbers are for bonus points for: Speed Weight Acceleration Handling Drift Off-Road Mini-Turbo and then there is table 2 Standard Bike S 39 21 51 51 54 43 48 Out Bullet Bike 53 24 32 35 67 29 67 In Bubble Bike / Jet Bubble 48 27 40 40 45 35 37 In [...] These are also the characteristics for the Bike or Kart. I wonder what's the most elegant solution for finding all the maximum combinations of Speed, Weight, Acceleration, etc, and also for the minimum, either by directly using the HTML on that page or copy and pasting the numbers into a text file. Actually, in that character table, Mario to Bower Jr are all medium characters, Baby Mario to Dry Bones are small characters, and the rest are all big characters, except the small, medium, or large Mii are just as what the name says. Small characters can only ride small bike or small kart, and so forth for medium and large.

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• ParseKit.framework won't work, Foundation.h not found

  - by Jeremy

  I'm really stumped trying to get the ParseKit.framework (this) to work in general, not even bothering to implement it till it runs the demo app that comes with it. What happens is the compiler can't locate < Foundation/Foundation.h or something, which I thought the header was in the linked framework. Exact error: "Lexical or Preprocessor Issue: 'Foundation/Foundation.h' file not found." Here's the code, just from the ParseKit_Prefix.pch: // // Prefix header for all source files of the 'ParseKit' target in the 'ParseKit' project. //#ifdef __OBJC__ #import <Foundation/Foundation.h> #endif Nothing unusual about it, did I mess up the file paths some how? I've reinstalled Xcode, re-downloaded the ParseKit, and nothing is helping. The suggestions here did nothing and it's not this. When I make a new project or use a different project and load the Foundation.framework and #import the header it works just fine. If I unlink the framework I can't find it to re-link again. Has anyone else had this kind of problem? Did I download it wrong somewhere? I have a very difficult time finding where exactly the Xcode UI links stuff, apple must get a kick out of frustrating people, so if anyone has anything they can think of please give me some feedback, I'm horribly confused right now. Thanks,

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• VB.NET - Find a Substring in an ArrayList, StringCollection or List(Of String)

  - by CJM

  I've got some code that creates a list of AD groups that the user is a member of, with the intention of saying 'if user is a member of GroupX then allow admin access, if not allow basic access'. I was using a StringCollection to store this list of Groups, and intended to use the Contains method to test for membership of my admin group, but the problem is that this method only compares the full string - but my AD groups values are formatted as cn=GroupX, etc.... I want to be easily able to determine if a particular substring (i.e. 'GroupX') appears in the list of groups. I could always iterate through the groups check each for a substring representing my AD group name, but I'm more interested in finding out if there is a 'better' way. Clearly there are a number of repositories for the list of Groups, and it appears that Generics (List(Of String)) are more commonly preferred (which I may well implement anyway) but there is no in-built means of checking for a substring using this method either. Any suggestions? Or should I just iterated through the list of groups?

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• Number of simple mutations to change one string to another?

  - by mstksg

  Hi; I'm sure you've all heard of the "Word game", where you try to change one word to another by changing one letter at a time, and only going through valid English words. I'm trying to implement an A* Algorithm to solve it (just to flesh out my understanding of A*) and one of the things that is needed is a minimum-distance heuristic. That is, the minimum number of one of these three mutations that can turn an arbitrary string a into another string b: 1) Change one letter for another 2) Add one letter at a spot before or after any letter 3) Remove any letter Examples aabca => abaca: aabca abca abaca = 2 abcdebf => bgabf: abcdebf bcdebf bcdbf bgdbf bgabf = 4 I've tried many algorithms out; I can't seem to find one that gives the actual answer every time. In fact, sometimes I'm not sure if even my human reasoning is finding the best answer. Does anyone know any algorithm for such purpose? Or maybe can help me find one? Thanks.

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• Moving UIScrollView in App

  - by jsetting32

  Currently, I am attempting to create the same effect as Yahoo! Weather's App where the vital day information is at the bottom of the page on the top of a UIScrollView, that's contained by a UIView. I am having a hard time thinking about how this is going to happen or how I should implement this. If the user taps on the top of the UIScrollView which is located near the bottom of the laoded UIView, and starts to scroll up (/), the UIScrollView's frame should be moved to the TOP of the current UIView's frame. So the UIScrollView's y-value should change to UIView's (self.view.frame.origin.y) if the user starts scrolling UP on the UIScrollView which is located on the UIView's y-pixel ~280. Here's what the UIViewController should look like in the beginning of loading the ViewController... Then once the user slides his finger from the bottom to the top of the screen... this should happen........ And when the user scrolls to the top of the UIScrollView with all the content within it... the view should go back to the start picture shown... How is this done? I was thinking several UIGestureRecognizer's and Instantiating the UIscrollview at the lower part of the UIView... _weatherView = [[UIScrollView alloc] initWithFrame:CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y + 250, self.view.bounds.size.width, self.view.bounds.size.height - 44)]; _weatherView.contentSize = CGSizeMake(self.view.bounds.size.width, self.view.bounds.size.height * 4); _weatherView.backgroundColor = [UIColor clearColor]; [self.view addSubview:_weatherView]; The adding some UIGestureRecognizer delegate method.... But anyone have any ideas on the UIGestureRecognizer delegate method? And how it should be implemented? I can write the psuedo-code but I am having problems finding the delegate methods :P Thank you!!! ---- Break Time.... :)

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• deep linking in Excel sheets exported to html

  - by pomarc

  hello everybody, I am working on a project where I must export to html a lot of Excel files. This is pretty straightforward using automation and saving as html. The problem is that many of these sheets have links to worksheets of some other files. I must find a way to write a link to a single inner worksheet. When you export a multisheet excel file to html, excel creates a main htm file, a folder named filename_file, and inside this folder it writes down several files: a css, an xml list of files, a file that creates the tab bar and several html files named sheetxxx.htm, each one representing a worksheet. When you open the main file, you can click the menu bar at the bottom which lets you select the appropriate sheet. This is in fact a link, which replaces a frame content with the sheetxxx.htm file. When this file is loaded a javascript function that selects the right tab gets called. The exported files will be published on a web site. I will have to post process each file and replace every link to the other xls files to the matching htm file, finding a way to open the right worksheet. I think that I could add a parameter to the processed htm file link url, such as myfile.htm?sh=sheet002.htm if I want to link to the second worksheet of myfile.htm (ex myfile.xls). After I've exported them, I could inject a simple javascript into each of the main files which, when they are loaded, could retrieve the sh parameter with jQuery (this is easy) and use this to somehow replace the frSheet frame contents (where the sheets get loaded), opening the right inner sheet and not the default sheet (this is what I call deep linking) mimicking what happens when a user clicks on a tab. This last step is missing... :) I am considering different options, such as replacing the source of the $("frSheet") frame after document.ready. I'd like to hear from you any advice on what could be the best way to realize that in your opinion. any help is greately appreciated, many thanks.

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• Windows Services in Win7?

  - by Brandi

  I am trying to make a service that spawns a desktop application, and then watches to make sure it restarts again if it is closed. . I would like it to basically spawn the process and then forget about it, allowing to act like a normal interactive application. (Apparently this is much easier to do in XP and before, but I need this for XP, Vista, and 7) My problem now is that either it shows up invisible if I use process.start() with desktop interactive checked, and if I directly spawn a form it asks "Do you REALLY want to do this?!" and then the whole screen goes blank EXCEPT for my program. I just want this to be an inoffensive background app. I have the app working well, I just need to figure out how to spawn it from a service without all the trouble. I am finding all of this stuff that says "Don't make services that have UI", but first off this was a requirement that was given to me. (Boss does not want it to be a scheduled task) Also, I noticed that the Task scheduler is itself a service, and it does not have any problem spawning user interactive applications. Why can't I do that too? What am I doing wrong?

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• How to draw complex shape from code behind for custom control in resource dictionary

  - by HopelessCoder

  Hi I am new to wpf and am having a problem which may or may not be trivial. I have defined a custom control as follows in the resource dictionary: <ResourceDictionary x:Class="SyringeSlider.Themes.Generic" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:SyringeSlider"> <Style TargetType="{x:Type local:CustomControl1}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type local:CustomControl1}"> <Border Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}"> <Canvas Height="{TemplateBinding Height}" Width="{TemplateBinding Width}" Name="syringeCanvas"> </Canvas> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> </ResourceDictionary> Unfortunately I cannot go beyond this because I would like to draw a geometry onto the canvas consisting of a set of multiple line geometries whose dimensions are calculated as a function of the space available in the canvas. I believe that I need a code behind method to do this, but have not been able to determine how to link the xaml definition to a code behind method. Note that I have set up a class x:Class="SyringeSlider.Themes.Generic" for specifically this purpose, but can't figure out which Canvas property to link the drawing method to. My drawing method looks like this private void CalculateSyringe() { int adjHeight = (int) Height - 1; int adjWidth = (int) Width - 1; // Calculate some very useful values based on the chart above. int borderOffset = (int)Math.Floor(m_borderWidth / 2.0f); int flangeLength = (int)(adjHeight * .05f); int barrelLeftCol = (int)(adjWidth * .10f); int barrelLength = (int)(adjHeight * .80); int barrelRightCol = adjWidth - barrelLeftCol; int coneLength = (int)(adjHeight * .10); int tipLeftCol = (int)(adjWidth * .45); int tipRightCol = adjWidth - tipLeftCol; int tipBotCol = adjWidth - borderOffset; Path mySyringePath = new Path(); PathGeometry mySyringeGeometry = new PathGeometry(); PathFigure mySyringeFigure = new PathFigure(); mySyringeFigure.StartPoint = new Point(0, 0); Point pointA = new Point(0, flangeLength); mySyringeFigure.Segments.Add(new LineSegment(pointA, true)); Point pointB = new Point(); pointB.Y = pointA.Y + barrelLength; pointB.X = 0; mySyringeFigure.Segments.Add(new LineSegment(pointB, true)); // You get the idea....Add more points in this way mySyringeGeometry.Figures.Add(mySyringeFigure); mySyringePath.Data = mySyringeGeometry; } SO my question is: 1) Does what I am trying to do make any sense? 2) Can a use a canvas for this purpose? If not, what are my other options? Thanks!

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• How do I find all paths through a set of given nodes in a DAG?

  - by Hanno Fietz

  I have a list of items (blue nodes below) which are categorized by the users of my application. The categories themselves can be grouped and categorized themselves. The resulting structure can be represented as a Directed Acyclic Graph (DAG) where the items are sinks at the bottom of the graph's topology and the top categories are sources. Note that while some of the categories might be well defined, a lot is going to be user defined and might be very messy. Example: On that structure, I want to perform the following operations: find all items (sinks) below a particular node (all items in Europe) find all paths (if any) that pass through all of a set of n nodes (all items sent via SMTP from example.com) find all nodes that lie below all of a set of nodes (intersection: goyish brown foods) The first seems quite straightforward: start at the node, follow all possible paths to the bottom and collect the items there. However, is there a faster approach? Remembering the nodes I already passed through probably helps avoiding unnecessary repetition, but are there more optimizations? How do I go about the second one? It seems that the first step would be to determine the height of each node in the set, as to determine at which one(s) to start and then find all paths below that which include the rest of the set. But is this the best (or even a good) approach? The graph traversal algorithms listed at Wikipedia all seem to be concerned with either finding a particular node or the shortest or otherwise most effective route between two nodes. I think both is not what I want, or did I just fail to see how this applies to my problem? Where else should I read?

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• Problem creating a custom input element using FluentHtml (MVCContrib)

  - by seth

  Hi there, I just recently started dabbling in ASP.NET MVC 1.0 and came across the wonderful MVCContrib. I had originally gone down the path of creating some extended html helpers, but after finding FluentHTML decided to try my hand at creating a custom input element. Basically I am wanting to ultimately create several custom input elements to make it easier for some other devs on the project I'm working on to add their input fields to the page and have all of my preferred markup to render for them. So, in short, I'd like to wrap certain input elements with additional markup.. A TextBox would be wrapped in an <li /> for example. I've created my custom input elements following Tim Scott's answer in another question on here: DRY in the MVC View. So, to further elaborate, I've created my class, "TextBoxListItem": public class TextBoxListItem : TextInput<TextBox> { public TextBoxListItem (string name) : base(HtmlInputType.Text, name) { } public TextBoxListItem (string name, MemberExpression forMember, IEnumerable<IBehaviorMarker> behaviors) : base(HtmlInputType.Text, name, forMember, behaviors) { } public override string ToString() { var liBuilder = new TagBuilder(HtmlTag.ListItem); liBuilder.InnerHtml = ToString(); return liBuilder.ToString(TagRenderMode.SelfClosing); } } I've also added it to my ViewModelContainerExtensions class: public static TextBox TextBoxListItem<T>(this IViewModelContainer<T> view, Expression<Func<T, object>> expression) where T : class { return new TextBoxListItem(expression.GetNameFor(view), expression.GetMemberExpression(), view.Behaviors) .Value(expression.GetValueFrom(view.ViewModel)); } And lastly, I've added it to ViewDataContainerExtensions as well: public static TextBox TextBoxListItem(this IViewDataContainer view, string name) { return new TextBox(name).Value(view.ViewData.Eval(name)); } I'm calling it in my view like so: <%= this.TextBoxListItem("username").Label("Username:") %> Anyway, I'm not getting anything other than the standard FluentHTML TextBox, not wrapped in <li></li> elements. What am I missing here? Thanks very much for any assistance.

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• python gui generate math equation

  - by Nero Dietrich

  I have a homework question for one specific item with python GUIs. My goal is to create a GUI that asks a random mathematical equation and if the equation is evaluated correctly, then I will receive a message stating that it is correct. My main problem is finding out where to place my statements so that they show up in the labels; I have 1 textbox which generates the random equation, the next textbox is blank for me to enter the solution, and then an "Enter" button at the end to evaluate my solution. It looks like this: [randomly generated equation][Empty space to enter solution] [ENTER] I've managed to get the layout and the evaluate parameters, but I don't know where to go from here. This is my code so far: class Equation(Frame): def __init__(self,parent=None): Frame.__init__(self, parent) self.pack() Equation.make_widgets(self) Equation.new_problem(self) def make_widgets(self): Label(self).grid(row=0, column=1) ent = Entry(self) ent.grid(row=0, column=1) Label(self).grid(row=0, column=2) ent = Entry(self) ent.grid(row=0, column=2) Button(self, text='Enter', command=self.evaluate).grid(row=0, column=3) def new_problem(self): pass def evaluate(self): result = eval(self.get()) self.delete(0, END) self.insert(END, result) print('Correct')

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• Practice of checking 'trueness' or 'equality' in conditional statements - does it really make sense?

  - by Senthil

  I remember many years back, when I was in school, one of my computer science teachers taught us that it was better to check for 'trueness' or 'equality' of a condition and not the negative stuff like 'inequality'. Let me elaborate - If a piece of conditional code can be written by checking whether an expression is true or false, we should check the 'trueness'. Example: Finding out whether a number is odd - it can be done in two ways: if ( num % 2 != 0 ) { // Number is odd } or if ( num % 2 == 1 ) { // Number is odd } When I was beginning to code, I knew that num % 2 == 0 implies the number is even, so I just put a ! there to check if it is odd. But he was like 'Don't check NOT conditions. Have the practice of checking the 'trueness' or 'equality' of conditions whenever possible.' And he recommended that I use the second piece of code. I am not for or against either but I just wanted to know - what difference does it make? Please don't reply 'Technically the output will be the same' - we ALL know that. Is it a general programming practice or is it his own programming practice that he is preaching to others?

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• Unable to use certain Fonts programatically in ASP.Net

  - by TooFat

  I am trying to programatically create a bitmap with a specified font in ASP.Net. The idea is that the text, font name, size color etc. will be passed in from variables and a bitmap of the text using the font etc will be returned. However, I have been finding that I am only able to do so using the following code with certain fonts. <div> <% string fontName = "Segoe Script"; //Change Font here System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(100, 100); System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(bmp); System.Drawing.Font fnt = new System.Drawing.Font(fontName, 20); System.Drawing.SolidBrush brush = new System.Drawing.SolidBrush(System.Drawing.Color.Red); graph.DrawString("Help", fnt, brush, new System.Drawing.Point(10, 10)); bmp.Save(@"C:\Development\Path\image1.bmp"); this.Image1.ImageUrl = "http://mysite/Images/image1.bmp"; %> <asp:Label ID="Label1" runat="server" Text="Label" Font-Names="Segoe Script"> <%Response.Write("Help"); %></asp:Label> //Change font here <asp:Image ID="Image1" runat="server" /> </div> If I change the font name in the areas indicated by the comments to Arial or Verdana both the image and the label appear with the correct font. If however, I change the font name in both locations to something "Segoe Script" the Label will show up in Segoe Script but the image is in what looks like Arial.

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• Testing approach for multi-threaded software

  - by Shane MacLaughlin

  I have a piece of mature geospatial software that has recently had areas rewritten to take better advantage of the multiple processors available in modern PCs. Specifically, display, GUI, spatial searching, and main processing have all been hived off to seperate threads. The software has a pretty sizeable GUI automation suite for functional regression, and another smaller one for performance regression. While all automated tests are passing, I'm not convinced that they provide nearly enough coverage in terms of finding bugs relating race conditions, deadlocks, and other nasties associated with multi-threading. What techniques would you use to see if such bugs exist? What techniques would you advocate for rooting them out, assuming there are some in there to root out? What I'm doing so far is running the GUI functional automation on the app running under a debugger, such that I can break out of deadlocks and catch crashes, and plan to make a bounds checker build and repeat the tests against that version. I've also carried out a static analysis of the source via PC-Lint with the hope of locating potential dead locks, but not had any worthwhile results. The application is C++, MFC, mulitple document/view, with a number of threads per doc. The locking mechanism I'm using is based on an object that includes a pointer to a CMutex, which is locked in the ctor and freed in the dtor. I use local variables of this object to lock various bits of code as required, and my mutex has a time out that fires my a warning if the timeout is reached. I avoid locking where possible, using resource copies where possible instead. What other tests would you carry out?

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• How to seek to a specific time in a RTP stream?

  - by Cipi

  I am streaming a prerecorded H264 video that has the following structure: [I] [x] [x] [x] [I] [x] [x] [x] [I]... In between the IDR (I-s in my structure) I have 32 (only 3 presented here) other frames (all other stuff that is not IDR like SEI, SPS, PPS... X-es) Now, let assume that the timing of my frames is such: TIME: 1 2 3 4 5 6 7 8 9 FRAME: [I] [x] [x] [x] [I] [x] [x] [x] [I]... Now i want to seek to the time 4. If I seek to that frame, and send it, the picture gets messed up because the decoder needs a IDR to decode it properly, so I resorted to finding the appropriate IDR (in this case one with the time 1) and sending it as the frame with the time 4. So now the picture is decoded properly, all is well... but... If my GOV is 32, and I need to send the non IDR frame that has the index 31, and if the time span between it and the corresponding IDR is 3 seconds, I actually get 3 seconds earlier then the time I want. Now, this is not precise, because I cannot seek to the half of the GOV time span. Also, I cant set smaller GOV, so I want other ideas... My other idea was to send the last known IDR, and then send all other non IDR frames that come before the one I want, only I would set for all of them RTP-TIME to be the same as the corresponding IDR. In this case the picture gets decoded perfectly, but now in the above case, 3 seconds that follow non IDR frame with the wanted time get fast paced in the decoder/player (there is no instantaneous seek)... Any ideas? Or I can only seek to IDR-s and not the frames in between?

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• connecting to secure database from website host

  - by jim

  Hello all, I've got a requirement to both read and write data via a .net webservice to a sqlserver database that's on a private network. this database is currently accessed via a vpn connection by remote client software (on standard desktop machines) to get latest product prices and to upload product stock sales. I've been tasked with finding a way to centralise this access from a webservice that the clients then access, rather than them using the vpn route to connect directly to the database. My question is related to my .net service's relationship to the sqlserver database. What are the options for connecting to a private network vpn from a domain host in order to achive the functionality of allowing the webservice to both read and write data to the database. For now, I'm not too concerned about the client connectivity and security (tho i appreciate that this will have to be worked out too), I'm really just interested in discovering the options available in order to allow my .net webservice to connect to the private network in as painless and transparent a way as posible. The option of switching the database onto public hosting is not an option, so I have to work with the sdcenario as described above for now, unless there's a compelling rationale presented to do otherwise. thanks all... jim

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• How to pair users? (Like Omegle.com)

  - by Carlos Dubus

  Hi, I'm trying to do an Omegle.com clone script, basically for learning purposes. I'm doing it in PHP/MySQL/AJAX. I'm having problems finding two users and connecting them. The purpose of omegle is connecting two users "randomly". What I'm doing right now is the following: When a user enters the website a session is assigned. There are 3 states for each session/user (Normal,Waiting,Chatting) At first the user has state Normal and a field "connected_to" = NULL If the users clicks the START button, a state of "Waiting" is assigned. Then it looks for another user with state Waiting, if doesn't find one then it keeps looping, waiting for the "connected_to" to change. The "connected_to" will change when other user click START and then find another user waiting and updates the sessions accordingly. Now this have several problems, like: A user only can be connected to one user at a time. In omegle you can open more than one chat simultaneously. I don't know if this is the best way. About the chat, each user is polling the events from the server with AJAX calls, I saw that omegle, instead of several HTTP requests each second (let's say), does ONE request and wait for an answer, that means that the PHP script is looping indefinitely until gets an answer.I did this using set_time_limit(30) each time the loop is started. Then when the Ajax call is done start over again. Is this approach correct? I will appreciate a LOT your answers, Thank you, Carlos

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• Euler Project Help (Problem 12) - Prime Factors and the like

  - by Richie_W

  I hate to have to ask, but I'm pretty stuck here. I need to test a sequence of numbers to find the first which has over 500 factors: http://projecteuler.net/index.php?section=problems&id=12 -At first I attempted to brute force the answer (finding a number with 480 after a LONG time) -I am now looking at determining the prime factors of a number and then use them to find all other factors. I am currently at the stage where I can get an array of prime factors for any number I input - i.e 300 has the prime factors 2 2 3 5 5 Using this array of prime factors I need to be able to calculate the remaining factors - This is the part I am stuck on. Basically, as I understand it, I need to calculate ALL possible combinations of the numbers in the array... i.e 2 * 2 2 * 2 * 3 2 * 2 * 3 * 5 2 * 3 2 * 3 * 3 ...and so forth - But where it gets interesting is with things like... 2 * 5 2 * 3 * 5 ...i.e Numbers which are not adjacent to each other in the array I can't think of a way to code this in a generic fashion for any length array... I need help! P.S - I am working in Java EDIT: My brute force code - As it has been suggested brute forcing the problem will work and so there may be an error in my code :( package euler.problem12; public class Solution { public static void main(String[] args) { int next = 1; int triangle = 0; int maxFactors = 0; while(true) { triangle = triangle + next; int factors = 1; int max = (int) triangle / 2; for(int i = 1; i <= max; ++i) { if(triangle % i == 0) { factors ++; } } if(factors > maxFactors) { maxFactors = factors; System.out.println(triangle + "\t" + factors); } next++; } } }

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• What algorithms compute directions from point A to point B on a map?

  - by A. Rex

  How do map providers (such as Google or Yahoo! Maps) suggest directions? I mean, they probably have real-world data in some form, certainly including distances but also perhaps things like driving speeds, presence of sidewalks, train schedules, etc. But suppose the data were in a simpler format, say a very large directed graph with edge weights reflecting distances. I want to be able to quickly compute directions from one arbitrary point to another. Sometimes these points will be close together (within one city) while sometimes they will be far apart (cross-country). Graph algorithms like Dijkstra's algorithm will not work because the graph is enormous. Luckily, heuristic algorithms like A* will probably work. However, our data is very structured, and perhaps some kind of tiered approach might work? (For example, store precomputed directions between certain "key" points far apart, as well as some local directions. Then directions for two far-away points will involve local directions to a key points, global directions to another key point, and then local directions again.) What algorithms are actually used in practice? PS. This question was motivated by finding quirks in online mapping directions. Contrary to the triangle inequality, sometimes Google Maps thinks that X-Z takes longer and is farther than using an intermediate point as in X-Y-Z. But maybe their walking directions optimize for another parameter, too? PPS. Here's another violation of the triangle inequality that suggests (to me) that they use some kind of tiered approach: X-Z versus X-Y-Z. The former seems to use prominent Boulevard de Sebastopol even though it's slightly out of the way. (Edit: this example doesn't work anymore, but did at the time of the original post. The one above still works as of early November 2009.)

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• How Can I Find a List of All Exceptions That a Given Library Function Throws in Python?

  - by b14ck

  Sorry for the long title, but it seems most descriptive for my question. Basically, I'm having a difficult time finding exception information in the official python documentation. For example, in one program I'm currently writing, I'm using the shutil libary's move function: from shutil import move move('somefile.txt', '/tmp/somefile.txt') That works fine, as long as I have write access to /tmp/, there is enough diskspace, and if all other requirements are satisfied. However, when writing generic code, it is often difficult to guarantee those factors, so one usually uses exceptions: from shutil import move try: move('somefile.txt', '/tmp/somefile.txt') except: print 'Move failed for some reason.' I'd like to actually catch the appropriate exceptions thrown instead of just catching everything, but I simply can't find a list of exceptions thrown for most python modules. Is there a way for me to see which exceptions a given function can throw, and why? This way I can make appropriate cases for each exception, eg: from shutil import move try: move('somefile.txt', '/tmp/somefile.txt') except PermissionDenied: print 'No permission.' except DestinationDoesNotExist: print "/tmp/ doesn't exist" except NoDiskSpace: print 'No diskspace available.' Answer points go to whoever can either link me to some relevant documentation that I've somehow overlooked in the official docs, or provide a sure-fire way to figure out exactly which exceptions are thrown by which functions, and why. Thanks!

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• How best to modernize the 2002-era J2EE app?

  - by user331465

  I have this friend.... I have this friend who works on a java ee application (j2ee) application started in the early 2000's. Currently they add a feature here and there, but have a large codebase. Over the years the team has shrunk by 70%. [Yes, the "i have this friend is". It's me, attempting to humorously inject teenage high-school counselor shame into the mix] Java, Vintage 2002 The application uses EJB 2.1, struts 1.x, DAO's etc with straight jdbc calls (mixture of stored procedures and prepared statements). No ORM. For caching they use a mixture of OpenSymphony OSCache and a home-grown cache layer. Over the last few years, they have spent effort to modernize the UI using ajax techniques and libraries. This largely involves javascript libaries (jquery, yui, etc). Client Side On the client side, the lack of upgrade path from struts1 to struts2 discouraged them from migrating to struts2. Other web frameworks became popular (wicket, spring , jsf). Struts2 was not the "clear winner". Migrating all the existing UI from Struts1 to Struts2/wicket/etc did not seem to present much marginal benefit at a very high cost. They did not want to have a patchwork of technologies-du-jour (subsystem X in Struts2, subsystem Y in Wicket, etc.) so developer write new features using Struts 1. Server Side On the server side, they looked into moving to ejb 3, but never had a big impetus. The developers are all comfortable with ejb-jar.xml, EJBHome, EJBRemote, that "ejb 2.1 as is" represented the path of least resistance. One big complaint about the ejb environment: programmers still pretend "ejb server runs in separate jvm than servlet engine". No app server (jboss/weblogic) has ever enforced this separation. The team has never deployed the ejb server on a separate box then the app server. The ear file contains multiple copies of the same jar file; one for the 'web layer' (foo.war/WEB-INF/lib) and one for the server side (foo.ear/). The app server only loads one jar. The duplications makes for ambiguity. Caching As for caching, they use several cache implementations: OpenSymphony cache and a homegrown cache. Jgroups provides clustering support Now What? The question: The team currently has spare cycles to to invest in modernizing the application? Where would the smart investor spend them? The main criteria: 1) productivity gains. Specifically reducing the time to develope new subsystems features and reduced maintenance. 2) performance/scalability. They do not care about fashion or techno-du-jour street cred. What do you all recommend? On the persistence side Switch everything (or new development only) to JPA/JPA2? Straight hibernate? Wait for Java EE 6? On the client/web-framework side: Migrate (some or all) to struts2? wicket? jsf/jsf2? As for caching: terracotta? ehcache? coherence? stick with what they have? how best to take advantage of the huge heap sizes that the 64-bit jvms offer? Thanks in advance.

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