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  • Why is the Clojure Hello World program so slow compared to Java and Python?

    - by viksit
    Hi all, I'm reading "Programming Clojure" and I was comparing some languages I use for some simple code. I noticed that the clojure implementations were the slowest in each case. For instance, Python - hello.py def hello_world(name): print "Hello, %s" % name hello_world("world") and result, $ time python hello.py Hello, world real 0m0.027s user 0m0.013s sys 0m0.014s Java - hello.java import java.io.*; public class hello { public static void hello_world(String name) { System.out.println("Hello, " + name); } public static void main(String[] args) { hello_world("world"); } } and result, $ time java hello Hello, world real 0m0.324s user 0m0.296s sys 0m0.065s and finally, Clojure - hellofun.clj (defn hello-world [username] (println (format "Hello, %s" username))) (hello-world "world") and results, $ time clj hellofun.clj Hello, world real 0m1.418s user 0m1.649s sys 0m0.154s Thats a whole, garangutan 1.4 seconds! Does anyone have pointers on what the cause of this could be? Is Clojure really that slow, or are there JVM tricks et al that need to be used in order to speed up execution? More importantly - isn't this huge difference in performance going to be an issue at some point? (I mean, lets say I was using Clojure for a production system - the gain I get in using lisp seems completely offset by the performance issues I can see here). The machine used here is a 2007 Macbook Pro running Snow Leopard, a 2.16Ghz Intel C2D and 2G DDR2 SDRAM. BTW, the clj script I'm using is from here and looks like, #!/bin/bash JAVA=/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home/bin/java CLJ_DIR=/opt/jars CLOJURE=$CLJ_DIR/clojure.jar CONTRIB=$CLJ_DIR/clojure-contrib.jar JLINE=$CLJ_DIR/jline-0.9.94.jar CP=$PWD:$CLOJURE:$JLINE:$CONTRIB # Add extra jars as specified by `.clojure` file if [ -f .clojure ] then CP=$CP:`cat .clojure` fi if [ -z "$1" ]; then $JAVA -server -cp $CP \ jline.ConsoleRunner clojure.lang.Repl else scriptname=$1 $JAVA -server -cp $CP clojure.main $scriptname -- $* fi

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  • Best Practice: QT4 QList<Mything*>... on Heap, or QList<Mything> using reference?

    - by Mike Crowe
    Hi Folks, Learning C++, so be gentle :)... I have been designing my application primarily using heap variables (coming from C), so I've designed structures like this: QList<Criteria*> _Criteria; // ... Criteria *c = new Criteria(....); _Criteria.append(c); All through my program, I'm passing pointers to specific Criteria, or often the list. So, I have a function declared like this: QList<Criteria*> Decision::addCriteria(int row,QString cname,QString ctype); Criteria * Decision::getCriteria(int row,int col) which inserts a Criteria into a list, and returns the list so my GUI can display it. I'm wondering if I should have used references, somehow. Since I'm always wanting that exact Criteria back, should I have done: QList<Criteria> _Criteria; // .... Criteria c(....); _Criteria.append(c); ... QList<Criteria>& Decision::addCriteria(int row,QString cname,QString ctype); Criteria& Decision::getCriteria(int row,int col) (not sure if the latter line is syntactically correct yet, but you get the drift). All these items are specific, quasi-global items that are the core of my program. So, the question is this: I can certainly allocate/free all my memory w/o an issue in the method I'm using now, but is there are more C++ way? Would references have been a better choice (it's not too late to change on my side). TIA Mike

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  • Programming tips for writing document editors?

    - by Tesserex
    I'm asking this because I'm in the process of writing two such editors for my Mega Man engine, one a tileset editor, and another a level editor. When I say document editor, I mean the superset application type for things like image editors and text editors. All of these share things like toolbars, menu options, and in the case of image editors, and my apps, tool panes. We all know there's tons of advice out there for interface design in these apps, but I'm wondering about programming advice. Specifically, I'm doubting my code designs with the following things: Many menu options toggle various behaviors. What's the proper way to reliably tie the checked state of the option with the status of the behavior? Sometimes it's more complicated, like options being disabled when there's no document loaded. More and more consensus seems to be against using MDI, but how should I control tool panes? For example, I can't figure out how to get the panels to minimize and maximize along with the main window, like Photoshop does. When tool panels are responsible for a particular part of the document, who actually owns that thing? The main window, or the panel class? How do you do communication between the tool panels and the main window? Currently mine is all event based but it seems like there could be a better way. This seems to be a common class of gui application, but I've never seen specific pointers on code design for them. Could you please offer whatever advice or experience you have for writing them?

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  • Word 2007 COM - Can't directly access a page when word is set to invisible

    - by Robbie
    I'm using Word 2007 via COM from PHP 5.2 Apache 2.0 on a windows machine. The goal is to programmatically render jpeg thumbnails from each page in a Word document. The following code works correctly if you set $word-Visible to 1: try { $word = new COM('word.application'); $word->Visible = 0; $word->Documents->Open("C:\\test.doc"); echo "Number of pages: " . $word->ActiveDocument->ActiveWindow->ActivePane->Pages->Count() . "</br>"; $i = 1; foreach ($word->ActiveDocument->ActiveWindow->ActivePane->Pages as $page) { echo "Page number: $i </br>"; $i++; } //get the EMF image of the page $data = $word->ActiveDocument->ActiveWindow->ActivePane->Pages->Item(3)->EnhMetaFileBits; $word->ActiveDocument->Close(); $word->Quit(); } catch (Exception $e) { echo "Exception: " .$e->getMessage(); } The test document I'm using contains 35 pages. The code will display the correct number of pages but the for each loop only loops over 1 page. I can only directly access page 1 and 2 in the Pages-Item() collection. If I try to access another page I get the exception: "The requested member of the collection does not exist." If I set the $word-Visible property to 1 I do get all the pages in the foreach loop and I can access any page directly. Everything is working as expected if Word is set to be visible. Even stranger is the fact that if I set Word to be invisible and I don't have the foreach loop I can only access page 1 instead of page 1 and 2 if I do the for each loop. Any pointers on how I can access all the pages in the document and keeping word invisible?

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  • Ruby on Rails - Static page as start page

    - by meetraghu28
    Hello! I am developing an app in RoR which has static and dynamic parts. The static portion is placed in the public/ folder of the app. Now if i have an index.html in my public folder then i will not be able to use the routes configured in my routes.rb The default configurations like map.connect /:controller/:action will not be usable if i have an index.html. So i removed the index html. Now i have a static page startpage.html in my public/ folder which has to be the starting page of the app. And the i have links in it for other static/dynamic pages. The RoR app is hosted in apache and i tried to configure the Virtual Host configuration by adding the DirectoryIndex param so that when ever a request comes for the site it will direct it to the startpage.html but still it takes me to the default controller that i have specified in routes.rb with map.root I dont want to add a dummy controller and action and create a view which has the startpage and configure routes.rb to use it as the root. What i am looking to do here is Basically startpage.html should be my first page in the app served as a static page from the public/ folder. This will then have links to other pages and controllers/actions Here i am not able to apache to redirect to the html page instead of passing on the control to rails application. Directory listing is also enabled by using Options Indexes but still no change. Any pointers anyone?

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  • Why isn't my new object being seen? C#

    - by Dan
    I am getting ready to take a class at a college on C#. I have been reading up on it a lot and decided to start a fun project. Here is what my project consists of: Main Control Form Configuration Form Arduino Program.cs calls Configuration.cs at start. This is where pin modes for the Arduino are set and where a timer is set. When I set these values, they get sent to MainControl.cs. When I hit the "Save" button in Configuration.cs, a MainControl.cs object is created [[I am correct in that?]] All of those values that were sent by Configuration.cs had corresponding setters that set private static variables in MainControl.cs [[ I don't really know if that is the preferred way, I am most definetly open to any suggestion anyone has]] MainControl.cs uses its default constructor, and this constructor calls a method that creates an arduino object from one of the private variables (serialPort) [[ Using this Arduino class Firmata.NET ]] When the arduino object is created, I know (I guess I do) because the form takes a few seconds to come up (As opposed to not using serial port) My problem is this: I do not understand why nothing can see the object I have been very wordy, I apologize if I wasn't concise. Here is the code: public partial class CMainControl : Form { private static string serialPort; public CMainControl() { InitializeComponent(); createArduino(); updateConfig(); // Change label values to values set in configuration } private void createArduino() { Arduino arduino = new Arduino(serialPort); } In Configuration.cs, when I set the serial port through a combobox, the value is sent to MainControl.cs just fine. Here is the error I get: Error 1 The name 'arduino' does not exist in the current context C:\Programming\Visual Studio\Workhead Demo\Workhead Demo\CMainControl.cs 94 13 Workhead Demo Please let me know if anyone can help and/or offer pointers, and please let me know if I didn't post or format anything correctly. Thank you very much :)

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  • Building a complex view with Three20 - resources?

    - by psychotik
    I'm using three20 for most of my iPhone app. One of the views I need to create is relatively complex. It needs a top bar (under the nav bar) with some controls and label, an image view below this bar (which occupies most of the body) and another bottom bar with more controls and labels (above the tab bar control). I don't have much UI experience - my only experience with anything UI is laying stuff out using CSS, etc on websites. Apple's online doc seems to assume that the reader knows a bunch about rectangles, layouts, frames, etc or is using InterfaceBuilder. And three20 isn't too well documented either. So my question is: Is it possible to design something like what I describe in IB and then still have a three20-based app use it? If so, any tips/pointers on how would be much appreciated. Can you point me to some documentation that explain how views/controls etc are rendered. I'm pretty sure I can figure it out if I find some decent explanation/tutorial for it.

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  • Starting a new business with former colleagues, advice needed

    - by Sparafusile
    I was recently contacted by a former boss of mine who is thinking of starting a new business. The business will be online only it will by my job to design, build, and maintain the software going into it. I will also have to maintain the server it's running on, being the only technical person on the team. I will be one of four members of the business, the other three being the actual business know-hows and salesmen. The other three are shouldering the cost of getting the business going (incorporation, attorney fees, etc) and we will be splitting the cost of the server. I have no business knowledge at all, and don't want any part of it, I am only interested in the technical aspects. Now that we are finalizing our plans, determining roles, and getting ready to start actual work, we have come to the point where we have to determine what percentage stake each of us has. Since I have never done anything like this before, or met anyone that has, I don't know what I should expect. Can anyone give me some pointers on what to ask for in this deal?

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  • httplib2 giving internal server error 500 with proxy

    - by NJTechie
    Following is the code and error it throws. It works fine without the proxy http = httplib2.Http() . Any pointers are highly appreciated! Usage : http = httplib2.Http(proxy_info = httplib2.ProxyInfo(socks.PROXY_TYPE_HTTP, '74.115.1.11', 80)) main_url = 'http://www.mywebsite.com' response, content = http.request(main_url, 'GET') Error : File "testproxy.py", line 17, in <module> response, content = http.request(main_url, 'GET') File "/home/kk/bin/pythonlib/httplib2/__init__.py", line 1129, in request (response, content) = self._request(conn, authority, uri, request_uri, method, body, headers, redirections, cachekey) File "/home/kk/bin/pythonlib/httplib2/__init__.py", line 901, in _request (response, content) = self._conn_request(conn, request_uri, method, body, headers) File "/home/kk/bin/pythonlib/httplib2/__init__.py", line 862, in _conn_request conn.request(method, request_uri, body, headers) File "/usr/lib/python2.5/httplib.py", line 866, in request self._send_request(method, url, body, headers) File "/usr/lib/python2.5/httplib.py", line 889, in _send_request self.endheaders() File "/usr/lib/python2.5/httplib.py", line 860, in endheaders self._send_output() File "/usr/lib/python2.5/httplib.py", line 732, in _send_output self.send(msg) File "/usr/lib/python2.5/httplib.py", line 699, in send self.connect() File "/home/kk/bin/pythonlib/httplib2/__init__.py", line 740, in connect self.sock.connect(sa) File "/home/kk/bin/pythonlib/socks.py", line 383, in connect self.__negotiatehttp(destpair[0],destpair[1]) File "/home/kk/bin/pythonlib/socks.py", line 349, in __negotiatehttp raise HTTPError((statuscode,statusline[2])) socks.HTTPError: (500, 'Internal Server Error')

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  • mocking collection behavior with Moq

    - by Stephen Patten
    Hello, I've read through some of the discussions on the Moq user group and have failed to find an example and have been so far unable to find the scenario that I have. Here is my question and code: // 6 periods var schedule = new List<PaymentPlanPeriod>() { new PaymentPlanPeriod(1000m, args.MinDate.ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(1).ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(2).ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(3).ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(4).ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(5).ToString()) }; // Now the proxy is correct with the schedule helper.Setup(h => h.GetPlanPeriods(It.IsAny<String>(), schedule)); Then in my tests I use Periods but the Mocked _PaymentPlanHelper never populates the collection, see below for usage: public IEnumerable<PaymentPlanPeriod> Periods { get { if (CanCalculateExpression()) _PaymentPlanHelper.GetPlanPeriods(this.ToString(), _PaymentSchedule); return _PaymentSchedule; } } Now if I change the mocked object to use another overloaded method of GetPlanPeriods that returns a List like so : var schedule = new List<PaymentPlanPeriod>() { new PaymentPlanPeriod(1000m, args.MinDate.ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(1).ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(2).ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(3).ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(4).ToString()), new PaymentPlanPeriod(1000m, args.MinDate.Value.AddMonths(5).ToString()) }; helper.Setup(h => h.GetPlanPeriods(It.IsAny<String>())).Returns(new List<PaymentPlanPeriod>(schedule)); List<PaymentPlanPeriod> result = new _PaymentPlanHelper.GetPlanPeriods(this.ToString()); This works as expected. Any pointers would be awesome, as long as you don't bash my architecture... :) Thank you, Stephen

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  • Automatically install and launch a code-signed application from Safari

    - by Thomas Jung
    Is it possible and if so what are the steps necessary to package (or build) a Mac OS X application and code-sign it so that it can be downloaded with Safari and automatically launch? ... possibly after the user responds to some sort of dialog explaining that it is a signed application and the publisher has been verified. An example of the user experience I am trying to create is "installing Google Chrome for the first time on Windows", which is a 3-click, less-than-a-minute process. For the concerned among you: I am not trying to create a drive-by download. I am fine with some sort of intermittent user step approving the download. I just want to make the installation as quick and painless as possible and not require the user drag the app from a mounted DMG into the application folder. This may not 100% jibe with established Mac OS X user interaction guidelines, but it would work better for the not-power users. I only need the high-level steps or pointers to resources ... my google-fu was weak on this one.

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  • NSString's stringByAppendingPathComponent: removes a '/' in http://

    - by Jasarien
    I've been modifying some code to work between Mac OS X and iPhone OS. I came across some code that was using NSURL's URLByAppendingPathComponent: (added in 10.6), which as some may know, isn't available in the iPhone SDK. My solution to make this code work between OS's is to use NSString *urlString = [myURL absoluteString]; urlString = [urlString stringByAppendingPathComponent:@"helloworld"]; myURL = [NSURL urlWithString:urlString]; The problem with this is that NSString's stringByAppendingPathComponent: seems to remove one of the /'s from the http:// part of the URL. Is this intended behaviour or a bug? Edit Ok, So I was a bit too quick in asking the question above. I re-read the documentation and it does say: Note that this method only works with file paths (not, for example, string representations of URLs) However, it doesn't give any pointers in the right direction for what to do if you need to append a path component to a URL on the iPhone... I could always just do it manually, adding a /if necessary and the extra string, but I was looking to keep it as close to the original Mac OS X code as possible...

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  • How to manually add a legend to a ggplot object

    - by Dan
    I have this data frame: structure(list(month_num = 1:24, founded_month = c(4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 1L, 2L, 3L), founded_year = c(2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2010L, 2010L, 2010L), count = c(270L, 222L, 256L, 250L, 277L, 268L, 246L, 214L, 167L, 408L, 201L, 225L, 203L, 220L, 230L, 225L, 177L, 207L, 166L, 135L, 116L, 122L, 69L, 42L), month_abb = c("Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "Jan", "Feb", "Mar"), short_year = c("08", "08", "08", "08", "08", "08", "08", "08", "08", "09", "09", "09", "09", "09", "09", "09", "09", "09", "09", "09", "09", "10", "10", "10" ), proj = c(282, 246, 292, 298, 337, 340, 330, 310, 275, 528, 333, 369, 359, 388, 410, 417, 381, 423, 394, 375, 368, 386, 345, 330), label = c("Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "Jan\n09", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "Jan\n10", "Feb", "Mar")), .Names = c("month_num", "founded_month", "founded_year", "count", "month_abb", "short_year", "proj", "label"), row.names = c(NA, -24L), class = "data.frame") and i've got all of this done (I know the code's a bit ugly looking, pointers appreciated): p <- ggplot(m_summary2, aes(x = month_num, y = count)) p + geom_line(colour = rgb(0/255, 172/255, 0/255)) + geom_point(colour = rgb(0/255, 172/255, 0/255)) + geom_line(aes(x = m_summary2$month_num, y = m_summary2$proj), colour = rgb(18/255, 111/255, 150/255)) + geom_point(aes(x = m_summary2$month_num, y = m_summary2$proj), colour = rgb(18/255, 111/255, 150/255)) + scale_x_continuous("Month", breaks = m_summary2$month_num, labels = m_summary2$label) + scale_y_continuous("# Startups Founded") + opts(title = paste("# Startups Founded:", m_summary2$month_abb[1], m_summary2$short_year[1], "-", m_summary2$month_abb[nrow(m_summary2)], m_summary2$short_year[nrow(m_summary2)])) Now I would like to add a legend to clarify that the blue line is a projection and the green line is the current data. Thanks in advance!

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  • Wrapping FUSE from Go

    - by Matt Joiner
    I'm playing around with wrapping FUSE with Go. However I've come stuck with how to deal with struct fuse_operations. I can't seem to expose the operations struct by declaring type Operations C.struct_fuse_operations as the members are lower case, and my pure-Go sources would have to use C-hackery to set the members anyway. My first error in this case is "can't set getattr" in what looks to be the Go equivalent of a default copy constructor. My next attempt is to expose an interface that expects GetAttr, ReadLink etc, and then generate C.struct_fuse_operations and bind the function pointers to closures that call the given interface. This is what I've got (explanation continues after code): package fuse // #include <fuse.h> // #include <stdlib.h> import "C" import ( //"fmt" "os" "unsafe" ) type Operations interface { GetAttr(string, *os.FileInfo) int } func Main(args []string, ops Operations) int { argv := make([]*C.char, len(args) + 1) for i, s := range args { p := C.CString(s) defer C.free(unsafe.Pointer(p)) argv[i] = p } cop := new(C.struct_fuse_operations) cop.getattr = func(*C.char, *C.struct_stat) int {} argc := C.int(len(args)) return int(C.fuse_main_real(argc, &argv[0], cop, C.size_t(unsafe.Sizeof(cop)), nil)) } package main import ( "fmt" "fuse" "os" ) type CpfsOps struct { a int } func (me *CpfsOps) GetAttr(string, *os.FileInfo) int { return -1; } func main() { fmt.Println(os.Args) ops := &CpfsOps{} fmt.Println("fuse main returned", fuse.Main(os.Args, ops)) } This gives the following error: fuse.go:21[fuse.cgo1.go:23]: cannot use func literal (type func(*_Ctype_char, *_Ctype_struct_stat) int) as type *[0]uint8 in assignment I'm not sure what to pass to these members of C.struct_fuse_operations, and I've seen mention in a few places it's not possible to call from C back into Go code. If it is possible, what should I do? How can I provide the "default" values for interface functions that acts as though the corresponding C.struct_fuse_operations member is set to NULL?

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  • Need help choosing database server

    - by The Pretender
    Good day everyone. Recently I was given a task to develop an application to automate some aspects of stocks trading. While working on initial architecture, the database dilemma emerged. What I need is a fast database engine which can process huge amounts of data coming in very fast. I'm fairly experienced in general programming, but I never faced a task of developing a high-load database architecture. I developed a simple MSSQL database schema with several many-to-many relationships during one of my projects, but that's it. What I'm looking for is some advice on choosing the most suitable database engine and some pointers to various manuals or books which describe high-load database development. Specifics of the project are as follows: OS: Windows NT family (Server 2008 / 7) Primary platform: .NET with C# Database structure: one table to hold primary items and two or three tables with foreign keys to the first table to hold additional information. Database SELECT requirements: Need super-fast selection by foreign keys and by combination of foreign key and one of the columns (presumably DATETIME) Database INSERT requirements: The faster the better :) If there'll be significant performance gain, some parts can be written in C++ with managed interfaces to the rest of the system. So once again: given all that stuff I just typed, please give me some advice on what the best database for my project is. Links or references to some manuals and books on the subject are also greatly appreciated. EDIT: I'll need to insert 3-5 rows in 2 tables approximately once in 30-50 milliseconds and I'll need to do SELECT with 0-2 WHERE clauses queries with similar rate.

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  • https google urlshortener request missing body

    - by Peter
    Hi, Just trying to get the new API for the goo.gl URL shortening service working on my iPhone, following the instructions on http://code.google.com/apis/urlshortener/v1/getting_started.html I'm set up and the API is enabled etc., but when I send a request in the recommended format: POST https://www.googleapis.com/urlshortener/v1/url Content-Type: application/json {"longUrl": "http://www.google.com/"} I get an error returned. The error is exactly the one listed on that page in the errors section for if you haven't passed in a longURL param. This makes me think that I'm not setting up the body of the POST request properly. Here's the code if you have any pointers... NSString *longURLString=@"http://www.stackoverflow.com"; NSString *googlRequestString=@"https://www.googleapis.com/urlshortener/v1/url"; NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:[NSURL URLWithString:googlRequestString]]; [request setHTTPMethod:@"POST"]; [request addValue:@"application/json" forHTTPHeaderField:@"Content-Type:"]; NSString *bodyString=[NSString stringWithFormat:@"{\"longUrl\": \"%@\"}",longURLString]; [request setHTTPBody:[bodyString dataUsingEncoding:NSUTF8StringEncoding]]; NSURLResponse *theResponse; NSError *error=nil; NSData *receivedData=[NSURLConnection sendSynchronousRequest:request returningResponse:&theResponse error:&error]; NSString *receivedString=[[NSString alloc] initWithData:receivedData encoding:NSUTF8StringEncoding]; NSLog(@"Received data: %@",receivedString); [receivedString release]; The NSLog returns: Received data: { "error": { "errors": [ { "domain": "global", "reason": "required", "message": "Required", "locationType": "parameter", "location": "resource.longUrl" } ], "code": 400, "message": "Required" } } which is exactly what Google says you get if you have not passed a longUrl parameter.... My guess is I'm missing something very obvious here :-) P

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  • how to know location of return address on stack c/c++

    - by Dr Deo
    i have been reading about a function that can overwrite its return address. void foo(const char* input) { char buf[10]; //What? No extra arguments supplied to printf? //It's a cheap trick to view the stack 8-) //We'll see this trick again when we look at format strings. printf("My stack looks like:\n%p\n%p\n%p\n%p\n%p\n% p\n\n"); //%p ie expect pointers //Pass the user input straight to secure code public enemy #1. strcpy(buf, input); printf("%s\n", buf); printf("Now the stack looks like:\n%p\n%p\n%p\n%p\n%p\n%p\n\n"); } It was sugggested that this is how the stack would look like Address of foo = 00401000 My stack looks like: 00000000 00000000 7FFDF000 0012FF80 0040108A <-- We want to overwrite the return address for foo. 00410EDE Question: -. Why did the author arbitrarily choose the second last value as the return address of foo()? -. Are values added to the stack from the bottom or from the top? apart from the function return address, what are the other values i apparently see on the stack? ie why isn't it filled with zeros Thanks.

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  • What's a good way of building up a String given specific start and end locations?

    - by Michael Campbell
    (java 1.5) I have a need to build up a String, in pieces. I'm given a set of (sub)strings, each with a start and end point of where they belong in the final string. Was wondering if there were some canonical way of doing this. This isn't homework, and I can use any licensable OSS, such as jakarta commons-lang StringUtils etc. My company has a solution using a CharBuffer, and I'm content to leave it as is (and add some unit tests, of which there are none (?!)) but the code is fairly hideous and I would like something easier to read. As I said this isn't homework, and I don't need a complete solution, just some pointers to libraries or java classes that might give me some insight. The String.Format didn't seem QUITE right... I would have to honor inputs too long and too short, etc. Substrings would be overlaid in the order they appear (in case of overlap). As an example of input, I might have something like: String:start:end FO:0:3 (string shorter than field) BAR:4:5 (String larger than field) BLEH:5:9 (String overlays previous field) I'd want to end up with FO BBLEH 01234567890

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  • WPF and Prism View Overlay

    - by Zaheer
    Hi, I need some help with overlaying views using the prism framework.Its a little more complexed than that so let me explain.I could be over-thinking this as well :D i have shell (wpf window) and i have 2 views(A & B - both usercontrols) in a module. when the shell loads it loads view A. On view A i have a button to "popup" view B for some user input. so naturally i would think to some sort of modal window/control, maybe even a popup. however the problem i face with the popup is that when i move the shell the popup remains fixed and it doesnt block events in view A. I've tried disabling view A to stop events being fired and i've also tried to use a to get the view B move with the shell. Only the canvas works but i now need a way to block it tho'. Is there anyway i can overlay a view on top of another view with prism? or how does everyone else create modal popups with prism & wpf? any advise or pointers would be greatly appreciated.

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  • What would be the safest way to store objects of classes derived from a common interface in a common

    - by Svenstaro
    I'd like to manage a bunch of objects of classes derived from a shared interface class in a common container. To illustrate the problem, let's say I'm building a game which will contain different actors. Let's call the interface IActor and derive Enemy and Civilian from it. Now, the idea is to have my game main loop be able to do this: // somewhere during init std::vector<IActor> ActorList; Enemy EvilGuy; Civilian CoolGuy; ActorList.push_back(EvilGuy); ActorList.push_back(CoolGuy); and // main loop while(!done) { BOOST_FOREACH(IActor CurrentActor, ActorList) { CurrentActor.Update(); CurrentActor.Draw(); } } ... or something along those lines. This example obviously won't work but that is pretty much the reason I'm asking here. I'd like to know: What would be the best, safest, highest-level way to manage those objects in a common heterogeneous container? I know about a variety of approaches (Boost::Any, void*, handler class with boost::shared_ptr, Boost.Pointer Container, dynamic_cast) but I can't decide which would be the way to go here. Also I'd like to emphasize that I want to stay away as far as possible from manual memory management or nested pointers. Help much appreciated :).

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  • 3 index buffers

    - by bobobobo
    So, in both D3D and OpenGL there's ability to draw from an index buffer. The OBJ file format however does something weird. It specifies a bunch of vertices like: v -21.499660 6.424470 4.069845 v -25.117170 6.418100 4.068025 v -21.663851 8.282170 4.069585 v -21.651890 6.420180 4.068675 v -25.128481 8.281520 4.069585 Then it specifies a bunch of normals like.. vn 0.196004 0.558984 0.805680 vn -0.009523 0.210194 -0.977613 vn -0.147787 0.380832 -0.912757 vn 0.822108 0.567581 0.044617 vn 0.597037 0.057507 -0.800150 vn 0.809312 -0.045432 0.585619 Then it specifies a bunch of tex coords like vt 0.1225 0.5636 vt 0.6221 0.1111 vt 0.4865 0.8888 vt 0.2862 0.2586 vt 0.5865 0.2568 vt 0.1862 0.2166 THEN it specifies "faces" on the model like: f 1/2/5 2/3/7 8/2/6 f 5/9/7 6/3/8 5/2/1 So, in trying to render this with vertex buffers, In OpenGL I can use glVertexPointer, glNormalPointer and glTexCoordPointer to set pointers to each of the vertex, normal and texture coordinate arrays respectively.. but when it comes down to drawing with glDrawElements, I can only specify ONE set of indices, namely the indices it should use when visiting the vertices. Ok, then what? I still have 3 sets of indices to visit. In d3d its much the same - I can set up 3 streams: one for vertices, one for texcoords, and one for normals, but when it comes to using IDirect3DDevice9::DrawIndexedPrimitive, I can still only specify ONE index buffer, which will index into the vertices array. So, is it possible to draw from vertex buffers using different index arrays for each of the vertex, texcoord, and normal buffers (EITHER d3d or opengl!)

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  • A simple WCF Service (POX) without complex serialization

    - by jammer59
    I'm a complete WCF novice. I'm trying to build a deploy a very, very simple IIS 7.0 hosted web service. For reasons outside of my control it must be WCF and not ASMX. It's a wrapper service for a pre-existing web application that simply does the following: 1) Receives a POST request with the request body XML-encapsulated form elements. Something like valuevalue. This is untyped XML and the XML is atomic (a form) and not a list of records/objects. 2) Add a couple of tags to the request XML and the invoke another HTTP-based service with a simple POST + bare XML -- this will actually be added by some internal SQL ops but that isn't the issue. 3) Receive the XML response from the 3rd party service and relay it as the response to the original calling client in Step 1. The clients (step 1) will be some sort of web-based scripting but could be anything .aspx, python, php, etc. I can't have SOAP and the usual WCF-based REST examples with their contracts and serialization have me confused. This seems like a very common and very simple problem conceptually. It would be easy to implement in code but IIS-hosted WCF is a requirement. Any pointers?

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  • What's a good way of building up a String where you specific start and end locations?

    - by Michael Campbell
    (java 1.5) I have a need to build up a String, in pieces. I'm given a set of (sub)strings, each with a start and end point of where they belong in the final string. Was wondering if there were some canonical way of doing this. This isn't homework, and I can use any licensable OSS, such as jakarta commons-lang StringUtils etc. My company has a solution using a CharBuffer, and I'm content to leave it as is (and add some unit tests, of which there are none (?!)) but the code is fairly hideous and I would like something easier to read. As I said this isn't homework, and I don't need a complete solution, just some pointers to libraries or java classes that might give me some insight. The String.Format didn't seem QUITE right... I would have to honor inputs too long and too short, etc. Substrings would be overlaid in the order they appear (in case of overlap). As an example of input, I might have something like: String:start:end FO:0:3 (string shorter than field) BAR:4:5 (String larger than field) BLEH:5:9 (String overlays previous field) I'd want to end up with FO BBLEH 01234567890

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  • .net Class "is not a member of" Class .. even though it is?

    - by Matt Thrower
    Hi, Looking over some older code, I've run into a strange namespace error. Let's say I have two projects, HelperProject and WebProject. The full namespace of each - as given in application properties - is myEmployer.HelperProject and myEmployer.Web.WebProject. The pages in the web project are full of statements that use classes from the helper project. There are no imports/using statements but there is a reference to the helper project added in the bin. A few example lines might be: myEmployer.HelperProject.StringHelper.GetFixedLengthText(Text, "", Me.Width, 11) myEmploter.HelperProject.Utils.StringHelper.EstimatePixelLength(Text, 11) However every line that is written in this manner is throwing the error 'HelperProject' is not a member of 'myEmployer'. If you declare the statements like this: HelperProject.StringHelper.GetFixedLengthText(Text, "", Me.Width, 11) HelperProject.Utils.StringHelper.EstimatePixelLength(Text, 11) Everything seems fine. In the solution object browser and the bin folder, HelperProject appears with its full namespace, myEmployer.HelperProject. I don't want to have to change all the statements, and besides I suspect this is masking a more fundamental problem here. But I have no idea what's going on. Can anyone offer any pointers please? Cheers, Matt

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  • session regeneration in tomcat ?

    - by shrini1000
    Hi, I am using Spring security to secure my Java web application which is deployed in tomcat. I found out that it is vulnerable to session fixation attacks because tomcat does not create a new session upon successful log in. On debugging some more, here's what I found. For the following code (which is supposed to create a new session - pl. note, it's just a snippet and not full code): HttpSession session = request.getSession(false); session.invalidate(); session = request.getSession(true); // we now have a new session I thought a new session will be created, but tomcat simply uses the same session that got invalidated and hence the session id does not change. I searched online and found a solution which uses a 'valve' - http://marvinsmutterings.blogspot.com/2010/02/fixing-session-fixation-in-liferay-on.html but could not get it to work because it's looking for a jboss logging class and when I add it to lib, I get a reflection exception and the server doesn't start up. I'm using tomcat 5.5.28. Will be glad to have any pointers. Pl. let me know if you need more details, since I don't want to make this post too long. Sincere thanks!

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