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  • PDFParsing & extracting the images only in iPhone application.

    - by sagar
    Hello - Every one. ** : My Query : ** I want to extract only images from entire pdf document. ( Using Objective C - for iPhone Application ) : My Efforts : I have gone through this link which has details regarding different operators of PDF Document. ( http://mail-archives.apache.org/mod_mbox/pdfbox-commits/200912.mbox/%[email protected]%3E ) I also studied this document - ( http://developer.apple.com/mac/library/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_pdf_scan/dq_pdf_scan.html#//apple_ref/doc/uid/TP30001066-CH220-TPXREF101 ) I also have gone through entire document of PDFReference.pdf ( From original Adobe Site ) PDFReference.pdf (Adobe Document - says that - for image there are following operators ) q Q BI EI I have placed following table get the image myTable = CGPDFOperatorTableCreate(); CGPDFOperatorTableSetCallback(myTable, "q", arrayCallback2); CGPDFOperatorTableSetCallback(myTable, "TJ", arrayCallback); CGPDFOperatorTableSetCallback(myTable, "Tj", stringCallback); I have following arrayCallback2 method for getting image void arrayCallback2(CGPDFScannerRef inScanner, void *userInfo) { // how to extract image from this code // means I have tried too many different ways. following is incorrect way & not giving image // CGPDFStreamRef stream; // represents a sequence of bytes // if (CGPDFDictionaryGetStream (d, "BI", &stream)){ // CGPDFDataFormat t=CGPDFDataFormatJPEG2000; // CFDataRef data = CGPDFStreamCopyData (stream, &t); // } } above arrayCallback2 method is called for operator "q", But I don't know How to extract the image from it. In short. What should be the solution for extracting the images from the pdf documents? Thanks in advance for your kind help. Sagar kothari.

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  • What OpenGL functions are not GPU accelerated?

    - by Xavier Ho
    I was shocked when I read this (from the OpenGL wiki): glTranslate, glRotate, glScale Are these hardware accelerated? No, there are no known GPUs that execute this. The driver computes the matrix on the CPU and uploads it to the GPU. All the other matrix operations are done on the CPU as well : glPushMatrix, glPopMatrix, glLoadIdentity, glFrustum, glOrtho. This is the reason why these functions are considered deprecated in GL 3.0. You should have your own math library, build your own matrix, upload your matrix to the shader. For a very, very long time I thought most of the OpenGL functions use the GPU to do computation. I'm not sure if this is a common misconception, but after a while of thinking, this makes sense. Old OpenGL functions (2.x and older) are really not suitable for real-world applications, due to too many state switches. This makes me realise that, possibly, many OpenGL functions do not use the GPU at all. So, the question is: Which OpenGL function calls don't use the GPU? I believe knowing the answer to the above question would help me become a better programmer with OpenGL. Please do share some of your insights.

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  • Parameter meaning of CBasePin::GetMediaType(int iPosition, ...) method

    - by user325320
    Thanks to everyone who views my question. http://msdn.microsoft.com/en-us/library/windows/desktop/dd368709(v=vs.85).aspx It is not very clear from the documentation regarding the iPosition parameter for virtual HRESULT GetMediaType( int iPosition, CMediaType *pMediaType ); It is said "Zero-based index value.", but what kind of index it is? the index of the samples? I have a source filter sending the H.264 NALU flows (MEDIASUBTYPE_AVC1) and it works very well except that the SPS/PPS may be changed after the video is played for a while. The SPS and PPS are appended to the MPEG2VIDEOINFO structure, which is passed in CMediaType::SetFormat method when GetMediaType method is called. and there is another version of GetMediaType which accepts the iPosition parameter. It seems I can use this method to update the SPS / PPS. My question is: What does the iPosition param mean, and how does Decoder Filter know which SPS/PPS are assigned for each NALU sample. HRESULT GetMediaType(int iPosition, CMediaType *pMediaType) { ATLTRACE( "\nGetMediaType( iPosition = %d ) ", iPosition); CheckPointer(pMediaType,E_POINTER); CAutoLock lock(m_pFilter->pStateLock()); if (iPosition < 0) { return E_INVALIDARG; } if (iPosition == 0) { pMediaType->InitMediaType(); pMediaType->SetType(&MEDIATYPE_Video); pMediaType->SetFormatType(&FORMAT_MPEG2Video); pMediaType->SetSubtype(&MEDIASUBTYPE_AVC1); pMediaType->SetVariableSize(); } int nCurrentSampleID; DWORD dwSize = m_pFlvFile->GetVideoFormatBufferSize(nCurrentSampleID); LPBYTE pBuffer = pMediaType->ReallocFormatBuffer(dwSize); memcpy( pBuffer, m_pFlvFile->GetVideoFormatBuffer(nCurrentSampleID), dwSize); pMediaType->SetFormat(pBuffer, dwSize); return S_OK; }

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  • jQuery Manual Resizable DIV

    - by JC
    Hi, I'm trying to create a resizable div without using jQuery's interface library. var myY = 0; var mouseDown = false; var originalHeight = 0; function resize(e){ if(mouseDown == true){ $("#cooldiv").height(originalHeight+e.pageY-myY); } } $(document).ready(function(){ $().mouseup(function(e){ myY = 0; mouseDown = false; originalHeight = 0; $().unbind("mousemove", resize); }); $("#resizeBar").mousedown(function(e){ myY = e.pageY; originalHeight = $("#cooldiv").height(); mouseDown = true; $().bind("mousemove", resize); }); }); ... <div id="cooldiv" style="width: 500px; height: 300px; background-color: #cccccc; position: relative;"> <div id="resizeBar" style="height: 10px; width: 500px; background-color: #aaaaaa; position: absolute; bottom: 0;"></div> </div> The first resize works fine(i.e. mousedown, mousemove then mouseup), but on subsequent (mousedown+mousemove)s, the browser attempts to drag the whole resizeBar div instead of properly resizing its parent container. On mouseup, the div then starts resizing "cooldiv" on mousemove without any mousedown required, until a further click of the mouse. These problems don't show up in Internet Explorer.

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  • Call .NET Webservice with Android

    - by Lasse P
    Hi, I know this question has been asked here before, but I don't think those answers were adequate for my needs. We have a SOAP webservice that is used for an iPhone application, but it is possible that we need an Android specific version or a proxy of the service, so we have the option to go with either SOAP or JSON. I have a few concerns about both methods: SOAP solution: Is it possible to generate java source code from a WSDL file, if so, will it include some kind of proxy class to invoke the webservice and will it work in the Android environment at all? Google has not provided any SOAP library in Android, so i need to use 3rd party, any suggestion? What about the performance/overhead with parsing and transmitting SOAP xml over the wire versus the JSON solution? JSON solution: There is a few classes in the Android sdk that will let me parse JSON, but does it support generic parsing, like if I want the result to be parsed as a complex type? Or would I need to implement that myself? I have read about 2 libraries before here on Stackoverflow, GSON an Jackson. What is the difference performance and usability (from a developers perspective) wise? Do you guys have any experince with either of those libraries? So i guess the big question is, what method to go with? I hope you can help me out. Thanks in advance :-)

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  • Does F# documentation have a way to search for functions by their types?

    - by Nathan Sanders
    Say I want to know if F# has a library function of type ('T -> bool) -> 'T list -> int ie, something that counts how many items of a list that a function returns true for. (or returns the index of the first item that returns true) I used to use the big list at the MSR site for F# before the documentation on MSDN was ready. I could just search the page for the above text because the types were listed. But now the MSDN documentation only lists types on the individual pages--the module page is a mush of descriptive text. Google kinda-sorta works, but it can't help with // compatible interfaces ('T -> bool) -> Seq<'T> -> int // argument-swaps Seq<'T> -> ('T -> bool) -> int // type-variable names ('a -> bool) -> Seq<'a> -> int // wrappers ('a -> bool) -> 'a list -> option<int> // uncurried versions ('T -> bool) * 'T list -> int // .NET generic syntax ('T -> bool) -> List<'T> -> int // methods List<'T> member : ('T -> bool) -> int Haskell has a standalone program for this called Hoogle. Does F# have an equivalent, like Fing or something?

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  • How to pass data to a C++0x lambda function that will run in a different thread?

    - by Dimitri C.
    In our company we've written a library function to call a function asynchronously in a separate thread. It works using a combination of inheritance and template magic. The client code looks as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, &DemoThread::SomeFunction, stringToPassByValue); Since the introduction of lambda functions I'd like to use it in combination with lambda functions. I'd like to write the following client code: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=]() { const std::string someCopy = stringToPassByValue; }); Now, with the Visual C++ 2010 this code doesn't work. What happens is that the stringToPassByValue is not copied. Instead the "capture by value" feature passes the data by reference. The result is that if the function is executed after stringToPassByValue has gone out of scope, the application crashes as its destructor is called already. So I wonder: is it possible to pass data to a lambda function as a copy? Note: One possible solution would be to modify our framework to pass the data in the lambda parameter declaration list, as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=](const std::string stringPassedByValue) { const std::string someCopy = stringPassedByValue; } , stringToPassByValue); However, this solution is so verbose that our original function pointer solution is both shorter and easier to read. Update: The full implementation of AsyncCall is too big to post here. In short, what happens is that the AsyncCall template function instantiates a template class holding the lambda function. This class is derived from a base class that contains a virtual Execute() function, and upon an AsyncCall() call, the function call class is put on a call queue. A different thread then executes the queued calls by calling the virtual Execute() function, which is polymorphically dispatched to the template class which then executes the lambda function.

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  • Crash using WscRegisterForChanges.

    - by user335126
    I'm trying to use the WscRegisterForChanges with C++ function in Windows 7. Documentation located here: http://msdn.microsoft.com/en-us/library/bb432507(v=VS.85).aspx My problem is that even though the callback properly executes, the code crashes when it gets to the end of the callback's execution. Here's the code in question. It's very simple, so I'm not sure why it's crashing: #include #include #include void SecurityCenterChangeOccurred(void *param) { printf("Change occurred!\n"); } int main() { HRESULT result = S_OK; HANDLE callbackRegistration = NULL; result = WscRegisterForChanges( NULL, &callbackRegistration, (LPTHREAD_START_ROUTINE)SecurityCenterChangeOccurred, NULL); while(1) { Sleep(100); } return 0; } My call stack looks like this when the crash occurs: 00faf6e8() ntdll.dll!_TppWorkerThread@4() + 0x1293 bytes kernel32.dll!@BaseThreadInitThunk@12() + 0x12 bytes ntdll.dll!___RtlUserThreadStart@8() + 0x27 bytes ntdll.dll!__RtlUserThreadStart@8() + 0x1b bytes If I add ExitThread(0); to the end of SecurityCenterChangeOccurred, I get an error and the following trace (So I don't think I should be using ExitThread): Unhandled exception at 0x7799852b (ntdll.dll) in WscRegisterForChangesCrash.exe: 0xC000071C: An invalid thread, handle %p, is specified for this operation. Possibly, a threadpool worker thread was specified. ntdll.dll!_TpCheckTerminateWorker@4() + 0x3ca2f bytes ntdll.dll!_RtlExitUserThread@4() + 0x30 bytes WscRegisterForChangesCrash.exe!SecurityCenterChangeOccurred(void * param=0x00000000) Line 8 + 0xa bytes C++ wscapi.dll!WorkItemWrapper() + 0x19 bytes ntdll.dll!_RtlpTpWorkCallback@8() + 0xdf bytes ntdll.dll!_TppWorkerThread@4() + 0x1293 bytes kernel32.dll!@BaseThreadInitThunk@12() + 0x12 bytes ntdll.dll!___RtlUserThreadStart@8() + 0x27 bytes ntdll.dll!__RtlUserThreadStart@8() + 0x1b bytes Does anyone have any ideas why this might be happening? To trigger the crash run the program and turn the firewall on or off.

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  • Problems with Getting Remote Contents using Google App Engine

    - by dade
    Here is the client side code. It is running insdide a Google Gadgets var params = {}; params[gadgets.io.RequestParameters.CONTENT_TYPE] = gadgets.io.ContentType.JSON; var url = "http://invplatformtest.appspot.com/getrecent/"; gadgets.io.makeRequest(url, response, params); The response function is: function response(obj) { var r = obj.data; alert(r['name']); } while on the server end, the python code sending the JSON is: class GetRecent(webapp.RequestHandler): def get(self): self.response.out.write({'name':'geocities'}) #i know this is where the problem is so how do i encode json in GAE? which is just supposed to send back a Json encoded string but when i run this, the javascript throws the following error: r is null alert(r['name']); If i were recieving just TEXT contents and my server send TEXT everything works fine. I only get this problem when am trying to send JSON. Where exactly is the problem? Am i encoding the JSON the wrong way on AppEngine? I tried using the JSON library but it looks as if this is not supported. Where is the problem exactly? :(

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  • Appropriate uses of Monad `fail` vs. MonadPlus `mzero`

    - by jberryman
    This is a question that has come up several times for me in the design code, especially libraries. There seems to be some interest in it so I thought it might make a good community wiki. The fail method in Monad is considered by some to be a wart; a somewhat arbitrary addition to the class that does not come from the original category theory. But of course in the current state of things, many Monad types have logical and useful fail instances. The MonadPlus class is a sub-class of Monad that provides an mzero method which logically encapsulates the idea of failure in a monad. So a library designer who wants to write some monadic code that does some sort of failure handling can choose to make his code use the fail method in Monad or restrict his code to the MonadPlus class, just so that he can feel good about using mzero, even though he doesn't care about the monoidal combining mplus operation at all. Some discussions on this subject are in this wiki page about proposals to reform the MonadPlus class. So I guess I have one specific question: What monad instances, if any, have a natural fail method, but cannot be instances of MonadPlus because they have no logical implementation for mplus? But I'm mostly interested in a discussion about this subject. Thanks! EDIT: One final thought occured to me. I recently learned (even though it's right there in the docs for fail) that monadic "do" notation is desugared in such a way that pattern match failures, as in (x:xs) <- return [] call the monad's fail. It seems like the language designers must have been strongly influenced by the prospect of some automatic failure handling built in to haskell's syntax in their inclusion of fail in Monad.

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  • Compiling scalafx for Java 7u7 (that contains JavaFX 2.2) on OS X

    - by akauppi
    The compilation instructions of scalafx says to do: export JAVAFX_HOME=/Path/To/javafx-sdk2.1.0-beta sbt clean compile package make-pom package-src However, with the new packaging of JavaFX as part of the Java JDK itself (i.e. 7u7 for OS X) there no longer seems to be such a 'javafx-sdkx.x.x' folder. The Oracle docs say that JavaFX JDK is placed alongside the main Java JDK (in same folders). So I do: $ export JAVAFX_HOME=/Library/Java/JavaVirtualMachines/jdk1.7.0_07.jdk $ sbt clean [warn] Using project/plugins/ (/Users/asko/Sources/scalafx/project/plugins) for plugin configuration is deprecated. [warn] Put .sbt plugin definitions directly in project/, [warn] .scala plugin definitions in project/project/, [warn] and remove the project/plugins/ directory. [info] Loading project definition from /Users/asko/Sources/scalafx/project/plugins/project [info] Loading project definition from /Users/asko/Sources/scalafx/project/plugins [error] java.lang.NullPointerException [error] Use 'last' for the full log. Project loading failed: (r)etry, (q)uit, (l)ast, or (i)gnore? Am I doing something wrong or is scalafx not yet compatible with the latest Java release (7u7, JavaFX 2.2). What can I do? http://code.google.com/p/scalafx/ Addendum ..and finally (following Igor's solution below) sbt run launches the colorful circles demo easily (well, if one has a supported GPU that is). Oracle claims that "JavaFX supports graphic hardware acceleration on any Mac OS X system that is Lion or later" but I am inclined to think the NVidia powered Mac Mini I'm using does software rendering. A recent MacBook Air (core i7) is a complete different beast! :)

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  • Get dragged / saved items state back from Sql Server

    - by user571507
    Ok i saw many post's on how to serialize the value of dragged items to get hash and they tell how to save them. Now the question is how do i persist the dragged items the next time when user log's in using the has value that i got eg: <ul class="list"> <li id="id_1"> <div class="item ui-corner-all ui-widget ui-widget-content"> </div> </li> <li id="id_2"> <div class="item ui-corner-all ui-widget ui-widget-content"> </div> </li> <li id="id_3"> <div class="item ui-corner-all ui-widget ui-widget-content"> </div> </li> <li id="id_4"> <div class="item ui-corner-all ui-widget"> </div> </li> </ul> which on serialize will give "id[]=1&id[]=2&id[]=3&id[]=4" Now think that i saved it to Sql server database in a single field called SortOrder. Now how do i get the items to these order again ? the code to make these sort is below,without which people didn't know which library i had used to sort and serialize <script type="text/javascript"> $(document).ready(function() { $(".list li").css("cursor", "move"); $(".list").sortable(); }); </script>

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  • Boost program will not working on Linux

    - by Martin Lauridsen
    Hi SOF, I have this program which uses Boost::Asio for sockets. I pretty much altered some code from the Boost examples. The program compiles and runs just like it should on Windows in VS. However, when I compile the program on Linux and run it, I get a Segmentation fault. I posted the code here The command I use to compile it is this: c++ -I/appl/htopopt/Linux_x86_64/NTL-5.4.2/include -I/appl/htopopt/Linux_x86_64/boost_1_43_0/include mpqs.cpp mpqs_polynomial.cpp mpqs_host.cpp -o mpqs_host -L/appl/htopopt/Linux_x86_64/NTL-5.4.2/lib -lntl -L/appl/htopopt/Linux_x86_64/gmp-4.2.1/lib -lgmp -lm -L/appl/htopopt/Linux_x86_64/boost_1_43_0/lib -lboost_system -lboost_thread -static -lpthread By commenting out code, I have found out that I get the Segmentation fault due to the following line: boost::asio::io_service io_service; Can anyone provide any assistance, as to what may be the problem (and the solution)? Thanks! Edit: I tried changing the program to a minimal example, using no other libraries or headers, just boost/asio.hpp: #define DEBUG 0 #include <boost/asio.hpp> int main(int argc, char* argv[]) { boost::asio::io_service io_service; return 0; } I also removed other library inclusions and linking on compilation, however this minimal example still gives me a segmentation fault.

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  • Call to a member function get_segment() error

    - by hogofwar
    I'm having this problem with this piece of PHP code: class Core { public function start() { require("funk/funks/libraries/uri.php"); $this->uri = new uri(); require("funk/core/loader.php"); $this->load = new loader(); if($this->uri->get_segment(1) != "" and file_exists("funk/pages/".$uri->get_segment(1).".php")){ Only a snippet of the code The best way I can explain it is that it is a class calling upon another class (uri.php) and i am getting the error: Fatal error: Call to a member function get_segment() on a non-object in /home/eeeee/public_html/private/funkyphp/funk/core/core.php on line 11 (the if($this-uri-get_segment(1) part) I'm having this problem a lot and it is really bugging me. the library code is: <?php class uri { private $server_path_info = ''; private $segment = array(); private $segments = 0; public function __construct() { $segment_temp = array(); $this->server_path_info = preg_replace("/\?/", "", $_SERVER["PATH_INFO"]); $segment_temp = explode("/", $this->server_path_info); foreach ($segment_temp as $key => $seg) { if (!preg_match("/([a-zA-Z0-9\.\_\-]+)/", $seg) || empty($seg)) unset($segment_temp[$key]); } foreach ($segment_temp as $k => $value) { $this->segment[] = $value; } unset($segment_temp); $this->segments = count($this->segment); } public function segment_exists($id = 0) { $id = (int)$id; if (isset($this->segment[$id])) return true; else return false; } public function get_segment($id = 0) { $id--; $id = (int)$id; if ($this->segment_exists($id) === true) return $this->segment[$id]; else return false; } } ?>

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  • Why does PEAR get installed to my user directory?

    - by webworm
    I am new to Linux and I am attempting to install the PHP PEAR library on a virtual server which is running Ubuntu. I am following a tutorial that covers installing PEAR but have run up against an area where I am confused. When running the PEAR installation program I am prompted as to what I want the INSTALL_PREFIX to be. Evidently the INSTALL_PREFIX, among other things, determines where PEAR will be installed. The tutorial suggest the value of INSTALL_PREFIX be the following path ... "/home/MY_USER_NAME/pear" where MY_USER_NAME = my user account Having come from a Windows world, applications are installed on the system where everyone can use them. If I install PEAR underneath my user directory will other developers on the system be able to make use of PEAR in their PHP scripts? I want to make PEAR available to all users and not just myself. Could someone explain to me the difference between installing for all users and installing just for myself? Does the install location matter? Should I be installing PEAR in a different location? Thanks for any suggestions. P.S. The tutorial I am following is located at the following URL ... http://articles.sitepoint.com/article/getting-started-with-pear/2

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  • RadioGroup onCheckedChanged function won't fire

    - by user1758088
    First time/long time. My app keeps track of restaurant servers' shift sales to help them budget. In the activity that displays past shifts, I've created a RadioGroup under the ListView so the server can choose lunch, dinner, or both. I've implemented RadioGroup.onCheckedChangeListener, but onCheckChanged never gets called. I also tried an anonymous inner class as listener, same result. I tried to copy/modify code from this answer: http://stackoverflow.com/a/9595528 ...but when I added the @Override to the callback function, the Eclipse compiler gave me an error (not warning) that the method must override a superclass, and the quick fix was to remove the override. I'm pretty sure the signatures are correct, as they were made with Eclipse's autocomplete and implement methods facilities. I then followed instructions to move my java compiler from 1.5 to 1.6, and none of the above listed behavior seemed to change. Here's the code I thing is relavent: public class DataActivity extends ListActivity implements OnCheckedChangeListener{ RadioButton rbBoth; RadioButton rbDinnerOnly; RadioButton rbLunchOnly; @Override public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.database); ... final RadioGroup rgGroup = (RadioGroup)findViewById(R.id.DataRadioGroup); rbBoth = (RadioButton)findViewById(R.id.RadioBoth); rbDinnerOnly = (RadioButton)findViewById(R.id.RadioDinnerOnly); rbLunchOnly = (RadioButton)findViewById(R.id.RadioLunchOnly); rgGroup.setOnCheckedChangeListener(this); populateAllShifts(); } ... public void onCheckedChanged(RadioGroup group, int checkedId) { rbLunchOnly.setText("Click!"); Toast.makeText(getApplicationContext(), "Lunch Only", Toast.LENGTH_LONG).show(); if(group.getCheckedRadioButtonId() == R.id.RadioBoth){ populateAllShifts(); return; } if(group.getCheckedRadioButtonId() == R.id.RadioLunchOnly){ populatLunchShifts(); return; } if(group.getCheckedRadioButtonId() == R.id.RadioDinnerOnly){ populateDinnerShifts(); return; } } There is a ListView in this class with a custom adapter, but if my understanding and my XML are correct, the RadioGroup should be outside of the list: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/llDataLayout" android:weightSum="5" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical"> <ListView android:layout_weight="4" android:layout_width="fill_parent" android:id="@android:id/list" android:layout_height="wrap_content"></ListView> <RadioGroup android:layout_weight="1" android:id="@+id/DataRadioGroup" android:orientation="horizontal" android:layout_height="wrap_content" android:layout_width="fill_parent"> <RadioButton android:text="Lunch and Dinner" android:textSize="10dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/RadioBoth"/> <RadioButton android:text="Dinner Only" android:textSize="10dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/RadioDinnerOnly"/> <RadioButton android:text="Lunch Only" android:textSize="10dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/RadioLunchOnly"/> </RadioGroup> </LinearLayout> Any ideas out there?

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  • Instrumenting a string

    - by George Polevoy
    Somewhere in C++ era i have crafted a library, which enabled string representation of the computation history. Having a math expression like: TScalar Compute(TScalar a, TScalar b, TScalar c) { return ( a + b ) * c; } I could render it's string representation: r = Compute(VerbalScalar("a", 1), VerbalScalar("b", 2), VerbalScalar("c", 3)); Assert.AreEqual(9, r.Value); Assert.AreEqual("(a+b)*c==(1+2)*3", r.History ); C++ operator overloading allowed for substitution of a simple type with a complex self-tracking entity with an internal tree representation of everything happening with the objects. Now i would like to have the same possibility for NET strings, only instead of variable names i would like to see a stack traces of all the places in code which affected a string. And i want it to work with existing code, and existing compiled assemblies. Also i want all this to hook into visual studio debugger, so i could set a breakpoint, and see everything that happened with a string. Which technology would allow this kind of things? I know it sound like an utopia, but I think visual studio code coverage tools actually do the same kind of job while instrumenting the assemblies.

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  • Calculate the number of ways to roll a certain number

    - by helloworld
    I'm a high school Computer Science student, and today I was given a problem to: Program Description: There is a belief among dice players that in throwing three dice a ten is easier to get than a nine. Can you write a program that proves or disproves this belief? Have the computer compute all the possible ways three dice can be thrown: 1 + 1 + 1, 1 + 1 + 2, 1 + 1 + 3, etc. Add up each of these possibilities and see how many give nine as the result and how many give ten. If more give ten, then the belief is proven. I quickly worked out a brute force solution, as such int sum,tens,nines; tens=nines=0; for(int i=1;i<=6;i++){ for(int j=1;j<=6;j++){ for(int k=1;k<=6;k++){ sum=i+j+k; //Ternary operators are fun! tens+=((sum==10)?1:0); nines+=((sum==9)?1:0); } } } System.out.println("There are "+tens+" ways to roll a 10"); System.out.println("There are "+nines+" ways to roll a 9"); Which works just fine, and a brute force solution is what the teacher wanted us to do. However, it doesn't scale, and I am trying to find a way to make an algorithm that can calculate the number of ways to roll n dice to get a specific number. Therefore, I started generating the number of ways to get each sum with n dice. With 1 die, there is obviously 1 solution for each. I then calculated, through brute force, the combinations with 2 and 3 dice. These are for two: There are 1 ways to roll a 2 There are 2 ways to roll a 3 There are 3 ways to roll a 4 There are 4 ways to roll a 5 There are 5 ways to roll a 6 There are 6 ways to roll a 7 There are 5 ways to roll a 8 There are 4 ways to roll a 9 There are 3 ways to roll a 10 There are 2 ways to roll a 11 There are 1 ways to roll a 12 Which looks straightforward enough; it can be calculated with a simple linear absolute value function. But then things start getting trickier. With 3: There are 1 ways to roll a 3 There are 3 ways to roll a 4 There are 6 ways to roll a 5 There are 10 ways to roll a 6 There are 15 ways to roll a 7 There are 21 ways to roll a 8 There are 25 ways to roll a 9 There are 27 ways to roll a 10 There are 27 ways to roll a 11 There are 25 ways to roll a 12 There are 21 ways to roll a 13 There are 15 ways to roll a 14 There are 10 ways to roll a 15 There are 6 ways to roll a 16 There are 3 ways to roll a 17 There are 1 ways to roll a 18 So I look at that, and I think: Cool, Triangular numbers! However, then I notice those pesky 25s and 27s. So it's obviously not triangular numbers, but still some polynomial expansion, since it's symmetric. So I take to Google, and I come across this page that goes into some detail about how to do this with math. It is fairly easy(albeit long) to find this using repeated derivatives or expansion, but it would be much harder to program that for me. I didn't quite understand the second and third answers, since I have never encountered that notation or those concepts in my math studies before. Could someone please explain how I could write a program to do this, or explain the solutions given on that page, for my own understanding of combinatorics? EDIT: I'm looking for a mathematical way to solve this, that gives an exact theoretical number, not by simulating dice

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  • jquery question

    - by OM The Eternity
    I am using the Jquery library to copy the text enter in one textfield to another textfield using a check box when clicked.. which is as follows <html> <head> <script src="js/jquery.js" ></script> </head> <body> <form> <input type="text" name="startdate" id="startdate" value=""/> <input type="text" name="enddate" id="enddate" value=""/> <input type="checkbox" name="checker" id="checker" /> </form> <script> $(document).ready(function(){ $("input#checker").bind("click",function(o){ if($("input#checker:checked").length){ $("#enddate").val($("#startdate").val()); }else{ $("#enddate").val(""); } }); } ); </script> </body> </html> now here i want the check box to be selected by default, so that the data entered in start date get copied automatically as check box is checked by default... so what event should be called here in jquery script? please help me in resolving this issue...

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  • ZEND - Creating custom routes without overwriting the default ones

    - by Pedro Cordeiro
    I'm trying to create something that looks like facebook's profile URL (http://facebook.com/username). So, at first I tried something like that: $router->addRoute( 'eventName', new Zend_Controller_Router_Route( '/:eventName', array( 'module' => 'default', 'controller' => 'event', 'action' => 'detail' ) ) ); I kept getting the following error: Fatal error: Uncaught exception 'Zend_Controller_Router_Exception' with message 'eventName is not specified' in /var/desenvolvimento/padroes/zf/ZendFramework-1.12.0/library/Zend/Controller/Plugin/Broker.php on line 336 Not only I was unable to make that piece of code work, all my default routes were (obviously) overwritten. So I have, for example, stuff like "mydomain.com/admin", that was now returning the same error (as it fell in the same pattern as /:eventName). What I need to do is to create this custom route, without overwriting the default ones and actually working (dûh). I have already checked the online docs and a lot (A LOT) of stuff on google, but I didn't find anything related to the error I'm getting or how to not overwrite the default routes. I'd appreciate anything that could point me the right direction. Thanks.

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  • Do I need to Salt and Hash a randomly generated token?

    - by wag2639
    I'm using Adam Griffiths's Authentication Library for CodeIgniter and I'm tweaking the usermodel. I came across a generate function that he uses to generate tokens. His preferred approach is to reference a value from random.org but I considered that superfluous. I'm using his fall back approach of randomly generating a 20 character long string: $length = 20; $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'; $token = ''; for ($i = 0; $i < $length; $i++) { $token .= $characters[mt_rand(0, strlen($characters)-1)]; } He then hashes this token using a salt (I'm combing code from different functions) sha1($this->CI->config->item('encryption_key').$str); I was wondering if theres any reason to to run the token through the salted hash? I've read that simply randomly generating strings was a naive way of making random passwords but is the sh1 hash and salt necessary? Note: I got my encryption_key from https://www.grc.com/passwords.htm (63 random alpha-numeric)

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  • Setting up isolated COM for multiple projects.

    - by Praneeth
    My solution consists of multiple projects all of which out type class library except one whose output type is windows application. The application references all the other projects. I also have a COM component which is referenced by some of the projects and the application also. I can setup the regfree COM by changing the Isolated property of the referenced COM component in visual studio to TRUE. The solution builds successfully and I can see the manifest file generated for that particular assembly or application. Now, my question is that do I need to do this for all the projects which reference the COM component? If yes, then I know that i cannot set the Isolated property to TRUE on more than one project(gives a build error) so how do I workaround this? I am relatively new to .net and don't know much regfree COM(i assume what i am doing IS regfree COM?). Any help I can get on this issue is greatly appreciated. Thanks. I am currently using VS 2008.

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  • Defend PHP; convince me it isn't horrible

    - by Jason L
    I made a tongue-in-cheek comment in another question thread calling PHP a terrible language and it got down-voted like crazy. Apparently there are lots of people here who love PHP. So I'm genuinely curious. What am I missing? What makes PHP a good language? Here are my reasons for disliking it: PHP has inconsistent naming of built-in and library functions. Predictable naming patterns are important in any design. PHP has inconsistent parameter ordering of built-in functions, eg array_map vs. array_filter which is annoying in the simple cases and raises all sorts of unexpected behaviour or worse. The PHP developers constantly deprecate built-in functions and lower-level functionality. A good example is when they deprecated pass-by-reference for functions. This created a nightmare for anyone doing, say, function callbacks. A lack of consideration in redesign. The above deprecation eliminated the ability to, in many cases, provide default keyword values for functions. They fixed this in PHP 5, but they deprecated the pass-by-reference in PHP 4! Poor execution of name spaces (formerly no name spaces at all). Now that name spaces exist, what do we use as the dereference character? Backslash! The character used universally for escaping, even in PHP! Overly-broad implicit type conversion leads to bugs. I have no problem with implicit conversions of, say, float to integer or back again. But PHP (last I checked) will happily attempt to magically convert an array to an integer. Poor recursion performance. Recursion is a fundamentally important tool for writing in any language; it can make complex algorithms far simpler. Poor support is inexcusable. Functions are case insensitive. I have no idea what they were thinking on this one. A programming language is a way to specify behavior to both a computer and a reader of the code without ambiguity. Case insensitivity introduces much ambiguity. PHP encourages (practically requires) a coupling of processing with presentation. Yes, you can write PHP that doesn't do so, but it's actually easier to write code in the incorrect (from a sound design perspective) manner. PHP performance is abysmal without caching. Does anyone sell a commercial caching product for PHP? Oh, look, the designers of PHP do. Worst of all, PHP convinces people that designing web applications is easy. And it does indeed make much of the effort involved much easier. But the fact is, designing a web application that is both secure and efficient is a very difficult task. By convincing so many to take up programming, PHP has taught an entire subgroup of programmers bad habits and bad design. It's given them access to capabilities that they lack the understanding to use safely. This has led to PHP's reputation as being insecure. (However, I will readily admit that PHP is no more or less secure than any other web programming language.) What is it that I'm missing about PHP? I'm seeing an organically-grown, poorly-managed mess of a language that's spawning poor programmers. So convince me otherwise!

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  • Using stringstream instead of `sscanf` to parse a fixed-format string

    - by John Dibling
    I would like to use the facilities provided by stringstream to extract values from a fixed-format string as a type-safe alternative to sscanf. How can I do this? Consider the following specific use case. I have a std::string in the following fixed format: YYYYMMDDHHMMSSmmm Where: YYYY = 4 digits representing the year MM = 2 digits representing the month ('0' padded to 2 characters) DD = 2 digits representing the day ('0' padded to 2 characters) HH = 2 digits representing the hour ('0' padded to 2 characters) MM = 2 digits representing the minute ('0' padded to 2 characters) SS = 2 digits representing the second ('0' padded to 2 characters) mmm = 3 digits representing the milliseconds ('0' padded to 3 characters) Previously I was doing something along these lines: string s = "20101220110651184"; unsigned year = 0, month = 0, day = 0, hour = 0, minute = 0, second = 0, milli = 0; sscanf(s.c_str(), "%4u%2u%2u%2u%2u%2u%3u", &year, &month, &day, &hour, &minute, &second, &milli ); The width values are magic numbers, and that's ok. I'd like to use streams to extract these values and convert them to unsigneds in the interest of type safety. But when I try this: stringstream ss; ss << "20101220110651184"; ss >> setw(4) >> year; year retains the value 0. It should be 2010. How do I do what I'm trying to do? I can't use Boost or any other 3rd party library, nor can I use C++0x.

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  • OSX launchctl programmatically as root

    - by Lukas1
    I'm trying to start samba service using launchctl from OSX app as root, but I get error status -60031. I can run without problems the command in Terminal: sudo launchctl load -F /System/Library/LaunchDaemons/com.apple.AppleFileServer.plist` In the objective-c code, I'm using (I know it's deprecated, but that really shouldn't be the issue here) AuthorizationExecuteWithPrivileges method. Here's the code: NSString *command = @"launchctl"; // Conversion of NSArray args to char** args here (not relevant part of the code) OSStatus authStatus = AuthorizationCreate(NULL, kAuthorizationEmptyEnvironment, kAuthorizationFlagDefaults, &_authRef); if (authStatus != errAuthorizationSuccess) { NSLog(@"Failed to create application authorization: %d", (int)authStatus); return; } FILE* pipe = NULL; AuthorizationFlags flags = kAuthorizationFlagDefaults; AuthorizationItem right = {kAuthorizationRightExecute, 0, NULL, 0}; AuthorizationRights rights = {1, &right}; // Call AuthorizationCopyRights to determine or extend the allowable rights. OSStatus stat = AuthorizationCopyRights(_authRef, &rights, NULL, flags, NULL); if (stat != errAuthorizationSuccess) { NSLog(@"Copy Rights Unsuccessful: %d", (int)stat); return; } OSStatus status = AuthorizationExecuteWithPrivileges(_authRef, command.UTF8String, flags, args, &pipe); if (status != errAuthorizationSuccess) { NSLog(@"Error executing command %@ with status %d", command, status); } else { // some other stuff } I have also tried using different flags then kAuthorizationFlagDefaults, but that led to either the same problem or error code -60011 - invalid flags. What am I doing wrong here, please?

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