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  • Passing an array of structs in C

    - by lelouch
    I'm having trouble passing an array of structs to a function in C. I've created the struct like this in main: int main() { struct Items { char code[10]; char description[30]; int stock; }; struct Items MyItems[10]; } I then access it like: MyItems[0].stock = 10; etc. I want to pass it to a function like so: ReadFile(MyItems); The function should read the array, and be able to edit it. Then I should be able to access the same array from other functions. I've tried heaps of declarations but none of them work. e.g. void ReadFile(struct Items[10]) I've had a look around for other questions, but the thing is they're all done different, with typedefs and asterisks. My teacher hasn't taught us pointers yet, so I'd like to do it with what I know. Any ideas? :S EDIT: Salvatore's answer is working after I fixed my prototype to: void ReadFile(struct Items[9]);

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  • Encrypt string with public key only

    - by vlahovic
    i'm currently working on a android project where i need to encrypt a string using 128 bit AES, padding PKCS7 and CBC. I don't want to use any salt for this. I've tried loads of different variations including PBEKey but i can't come up with working code. This is what i currently have: String plainText = "24124124123"; String pwd = "BobsPublicPassword"; byte[] key = pwd.getBytes(); key = cutArray(key, 16); byte[] input = plainText.getBytes(); byte[] output = null; SecretKeySpec keySpec = null; keySpec = new SecretKeySpec(key, "AES"); Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding"); cipher.init(Cipher.ENCRYPT_MODE, keySpec); output = cipher.doFinal(input); private static byte[] cutArray(byte[] arr, int length){ byte[] resultArr = new byte[length]; for(int i = 0; i < length; i++ ){ resultArr[i] = arr[i]; } return resultArr; } Any help appreciated //Vlahovic

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  • When memory is actually freeded?

    - by zhyk
    Hello all. I'm trying to understand memory management stuff in Objective-C. If I see the memory usage listed by Activity Monitor, it looks like memory is not being freed (I mean column rsize). But in "Object Allocations" everything looks fine. Here is my simple code: #import <Foundation/Foundation.h> int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSInteger i, k=10000; while (k>0) { NSMutableArray *array = [[NSMutableArray alloc]init]; for (i=0;i<1000*k; i++) { NSString *srtring = [[NSString alloc] initWithString:@"string...."]; [array addObject:srtring]; [srtring release]; srtring = nil; } [array release]; array = nil; k-=500; } [NSThread sleepForTimeInterval:5]; [pool release]; return 0; } As for retain and release it's cool, everything is balanced. But rsize decreases only after quitting from this little program. Is it possible to "clean" memory somehow before quitting?

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  • C#. How to pass message from unsafe callback to managed code?

    - by maxima120
    Is there a simple example of how to pass messages from unsafe callback to managed code? I have a proprietary dll which receives some messages packed in structs and all is coming to a callback function. The example of usage is as follows but it calls unsafe code too. I want to pass the messages into my application which is all managed code. *P.S. I have no experience in interop or unsafe code. I used to develop in C++ 8 yrs ago but remember very little from that nightmarish times :) P.P.S. The application is loaded as hell, the original devs claim it processes 2mil messages per sec.. I need a most efficient solution.* static unsafe int OnCoreCallback(IntPtr pSys, IntPtr pMsg) { // Alias structure pointers to the pointers passed in. CoreSystem* pCoreSys = (CoreSystem*)pSys; CoreMessage* pCoreMsg = (CoreMessage*)pMsg; // message handler function. if (pCoreMsg->MessageType == Core.MSG_STATUS) OnCoreStatus(pCoreSys, pCoreMsg); // Continue running return (int)Core.CALLBACKRETURN_CONTINUE; } Thank you.

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  • Qt 101: Why can't I use this class?

    - by Airjoe
    I have experience with C++ but I've never really used Qt before. I'm trying to connect to a SQLite database, so I found a tutorial here and am going with that. In the QtCreator IDE, I went to Add New -- C++ Class and in the header file pasted in the header the header from that link and in the .cpp file I pasted the source. My main.cpp looks like this: #include <QtGui/QApplication> #include "mainwindow.h" #include "databasemanager.h" #include <qlabel.h> int main(int argc, char *argv[]) { QApplication a(argc, argv); MainWindow w; w.show(); DatabaseManager db(); QLabel hello("nothing..."); if(db.openDB()){ hello.setText("Win!"); } else{ hello.setText("Lame!"); } hello.resize(100, 30); hello.show(); return a.exec(); } And I'm getting this error: main.cpp:13: error: request for member 'openDB' in 'db', which is of non-class type 'DatabaseManager()' Can anyone point me in the right direction? I know "copypaste" code isn't good, I just wanted to see if I could get DB connectivity working and I figured something like this would be simple... thanks for the help.

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  • C# - Advantages/Disadvantages of different implementations for Comparing Objects

    - by Kevin Crowell
    This questions involves 2 different implementations of essentially the same code. First, using delegate to create a Comparison method that can be used as a parameter when sorting a collection of objects: class Foo { public static Comparison<Foo> BarComparison = delegate(Foo foo1, Foo foo2) { return foo1.Bar.CompareTo(foo2.Bar); }; } I use the above when I want to have a way of sorting a collection of Foo objects in a different way than my CompareTo function offers. For example: List<Foo> fooList = new List<Foo>(); fooList.Sort(BarComparison); Second, using IComparer: public class BarComparer : IComparer<Foo> { public int Compare(Foo foo1, Foo foo2) { return foo1.Bar.CompareTo(foo2.Bar); } } I use the above when I want to do a binary search for a Foo object in a collection of Foo objects. For example: BarComparer comparer = new BarComparer(); List<Foo> fooList = new List<Foo>(); Foo foo = new Foo(); int index = fooList.BinarySearch(foo, comparer); My questions are: What are the advantages and disadvantages of each of these implementations? What are some more ways to take advantage of each of these implementations? Is there a way to combine these implementations in such a way that I do not need to duplicate the code? Can I achieve both a binary search and an alternative collection sort using only 1 of these methods?

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  • Cross-platform iteration of Unicode string

    - by kizzx2
    I want to iterate each character of a Unicode string, treating each surrogate pair and combining character sequence as a single unit (one grapheme). Example The text "??????" is comprised of the code points: U+0928, U+092E, U+0938, U+094D, U+0924, U+0947, of which, U+0938 and U+0947 are combining marks. static void Main(string[] args) { const string s = "??????"; Console.WriteLine(s.Length); // Ouptuts "6" var l = 0; var e = System.Globalization.StringInfo.GetTextElementEnumerator(s); while(e.MoveNext()) l++; Console.WriteLine(l); // Outputs "4" } So there we have it in .NET. We also have Win32's CharNextW() #include <Windows.h> #include <iostream> #include <string> int main() { const wchar_t * s = L"??????"; std::cout << std::wstring(s).length() << std::endl; // Gives "6" int l = 0; while(CharNextW(s) != s) { s = CharNextW(s); ++l; } std::cout << l << std::endl; // Gives "4" return 0; } Question Both ways I know of are specific to Microsoft. Are there portable ways to do it? I heard about ICU but I couldn't find something related quickly (UnicodeString(s).length() still gives 6). Would be an acceptable answer to point to the related function/module in ICU. C++ doesn't have a notion of Unicode, so a lightweight cross-platform library for dealing with these issues would make an acceptable answer.

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  • Androids ExpandableListView - where to put the button listener for buttons that are children

    - by CommonKnowledge
    I have been playing around a lot with the ExpandableListView and I cannot figure out where to add the button listeners for the button that will be the children in the view. I did manage to get a button listener working that uses getChildView() below, but it seems to be the same listener for all the buttons. The best case scenario is that I would be able to implement the button listeners in the class that instantiates the ExpandableListAdapter class, and not have to put the listeners in the actual ExpandableListAdapter class. At this point I don't even know if that is possible I have been experimenting with this tutorial/code: HERE getChildView() @Override public View getChildView(int set_new, int child_position, boolean view, View view1, ViewGroup view_group1) { ChildHolder childHolder; if (view1 == null) { view1 = LayoutInflater.from(info_context).inflate(R.layout.list_group_item_lv, null); childHolder = new ChildHolder(); childHolder.section_btn = (Button)view1.findViewById(R.id.item_title); view1.setTag(childHolder); childHolder.section_btn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { Toast.makeText(info_context, "button pushed", Toast.LENGTH_SHORT).show(); } }); }else { childHolder = (ChildHolder) view1.getTag(); } childHolder.section_btn.setText(children_collection.get(set_new).GroupItemCollection.get(child_position).section); Typeface tf = Typeface.createFromAsset(info_context.getAssets(), "fonts/AGENCYR.TTF"); childHolder.section_btn.setTypeface(tf); return view1; } Any help would be much appreciated. Thank you and I will be standing by.

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  • Cannot overload function

    - by anio
    So I've got a templatized class and I want to overload the behavior of a function when I have specific type, say char. For all other types, let them do their own thing. However, c++ won't let me overload the function. Why can't I overload this function? I really really do not want to do template specialization, because then I've got duplicate the entire class. Here is a toy example demonstrating the problem: http://codepad.org/eTgLG932 The same code posted here for your reading pleasure: #include <iostream> #include <cstdlib> #include <string> struct Bar { std::string blah() { return "blah"; } }; template <typename T> struct Foo { public: std::string doX() { return m_getY(my_t); } private: std::string m_getY(char* p_msg) { return std::string(p_msg); } std::string m_getY(T* p_msg) { return p_msg->blah(); } T my_t; }; int main(int, char**) { Foo<char> x; Foo<Bar> y; std::cout << "x " << x.doX() << std::endl; return EXIT_SUCCESS; } Thank you everyone for your suggestions. Two valid solutions have been presented. I can either specialize the doX method, or specialize m_getY() method. At the end of the day I prefer to keep my specializations private rather than public so I'm accepting Krill's answer.

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  • Overloading generic implicit conversions

    - by raichoo
    Hi I'm having a little scala (version 2.8.0RC1) problem with implicit conversions. Whenever importing more than one implicit conversion the first one gets shadowed. Here is the code where the problem shows up: // containers class Maybe[T] case class Nothing[T]() extends Maybe[T] case class Just[T](value: T) extends Maybe[T] case class Value[T](value: T) trait Monad[C[_]] { def >>=[A, B](a: C[A], f: A => C[B]): C[B] def pure[A](a: A): C[A] } // implicit converter trait Extender[C[_]] { class Wrapper[A](c: C[A]) { def >>=[B](f: A => C[B])(implicit m: Monad[C]): C[B] = { m >>= (c, f) } def >>[B](b: C[B])(implicit m: Monad[C]): C[B] = { m >>= (c, { (x: A) => b } ) } } implicit def extendToMonad[A](c: C[A]) = new Wrapper[A](c) } // instance maybe object maybemonad extends Extender[Maybe] { implicit object MaybeMonad extends Monad[Maybe] { override def >>=[A, B](a: Maybe[A], f: A => Maybe[B]): Maybe[B] = { a match { case Just(x) => f(x) case Nothing() => Nothing() } } override def pure[A](a: A): Maybe[A] = Just(a) } } // instance value object identitymonad extends Extender[Value] { implicit object IdentityMonad extends Monad[Value] { override def >>=[A, B](a: Value[A], f: A => Value[B]): Value[B] = { a match { case Value(x) => f(x) } } override def pure[A](a: A): Value[A] = Value(a) } } import maybemonad._ //import identitymonad._ object Main { def main(args: Array[String]): Unit = { println(Just(1) >>= { (x: Int) => MaybeMonad.pure(x) }) } } When uncommenting the second import statement everything goes wrong since the first "extendToMonad" is shadowed. However, this one works: object Main { implicit def foo(a: Int) = new { def foobar(): Unit = { println("Foobar") } } implicit def foo(a: String) = new { def foobar(): Unit = { println(a) } } def main(args: Array[String]): Unit = { 1 foobar() "bla" foobar() } } So, where is the catch? What am I missing? Regards, raichoo

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  • Problem with UITextView

    - by user367039
    I have a strange problem with trying to pass a string from one viewcontroller to another view controller if the string originates from a UITextview instead of UITextfield. Both UITextview.text and UITextfield.text are of type NSString. The following code takes either Textfield.text or Textview.text depending on the fieldType and puts it into a string called aString. NSString *aString = [[NSString alloc] init]; if (fieldType == 3) { aString = textView.text; } else { aString = textField.text; } When I examine aString on either cases, I can see that it has successfully assigned the text into aString. I then pass the string to the other view controller using this code. [delegate updateSite:aString :editedFieldKey :fieldType]; [self.navigationController popViewControllerAnimated:YES]; This works fine if aString originated from textfield.text but nothing happens except the view controller is popped if aString was from textview.text This is the code that takes aString and does stuff with it, however it doesn't even execute the first line of code "NSLog(@"Returned object: %@, field type:%@", aString,editedFieldKey);" if aString was from textview.text Any help will be appreciated. -(void)updateSite:(NSString *)aString :(NSString *)editedFieldKey :(int)fieldType { NSLog(@"Returned object: %@, field type:%@", aString,editedFieldKey); switch (fieldType) { case 0: //string [aDiveSite setValue:aString forKey:editedFieldKey] ; NSLog(@"String set %@",[aDiveSite valueForKey:editedFieldKey] ); break; case 1: //int [aDiveSite setValue:[NSNumber numberWithInt:aString.intValue] forKey:editedFieldKey]; NSLog(@"Integer set"); break; case 2: //float NSLog(@"Saving floating value"); [aDiveSite setValue:[NSNumber numberWithFloat:aString.floatValue] forKey:editedFieldKey]; NSLog(@"Float set"); break; case 3: //Text view [aDiveSite setValue:aString forKey:editedFieldKey]; NSLog(@"Textview text saved"); default: break; } [self.tableView reloadData]; }

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  • What is different about C++ math.h abs() compared to my abs()

    - by moka
    I am currently writing some glsl like vector math classes in c++, and I just implemented an abs() function like this: template<class T> static inline T abs(T _a) { return _a < 0 ? -_a : _a; } I compared its speed to the default c++ abs from math.h like this: clock_t begin = clock(); for(int i=0; i<10000000; ++i) { float a = abs(-1.25); }; clock_t end = clock(); unsigned long time1 = (unsigned long)((float)(end-begin) / ((float)CLOCKS_PER_SEC/1000.0)); begin = clock(); for(int i=0; i<10000000; ++i) { float a = myMath::abs(-1.25); }; end = clock(); unsigned long time2 = (unsigned long)((float)(end-begin) / ((float)CLOCKS_PER_SEC/1000.0)); std::cout<<time1<<std::endl; std::cout<<time2<<std::endl; Now the default abs takes about 25ms while mine takes 60. I guess there is some low level optimisation going on. Does anybody know how math.h abs works internally? The performance difference is nothing dramatic, but I am just curious!

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  • Recursive QuickSort suffering a StackOverflowException -- Need fresh eyes

    - by jon
    I am working on a Recursive QuickSort method implementation in a GenericList Class. I will have a second method that accepts a compareDelegate to compare different types, but for development purposes I'm sorting a GenericList<int I am recieving stackoverflow areas in different places depending on the list size. I've been staring at and tracing through this code for hours and probably just need a fresh pair of (more experienced)eyes. Definitely wanting to learn why it is broken, not just how to fix it. public void QuickSort() { int i, j, lowPos, highPos, pivot; GenericList<T> leftList = new GenericList<T>(); GenericList<T> rightList = new GenericList<T>(); GenericList<T> tempList = new GenericList<T>(); lowPos = 1; highPos = this.Count; if (lowPos < highPos) { pivot = (lowPos + highPos) / 2; for (i = 1; i <= highPos; i++) { if (this[i].CompareTo(this[pivot]) <= 0) leftList.Add(this[i]); else rightList.Add(this[i]); } leftList.QuickSort(); rightList.QuickSort(); for(i=1;i<=leftList.Count;i++) tempList.Add(leftList[i]); for(i=1;i<=rightList.Count;i++) tempList.Add(rightList[i]); this.items = tempList.items; this.count = tempList.count; } }

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  • Javascript CS-PRNG - 64-bit random

    - by Jack
    Hi, I need to generate a cryptographically secure 64-bit unsigned random integer in Javascript. The first problem is that Javascript only allows 64-bit signed integers, so 9223372036854775808 is the biggest supported integer without going into floating point use I think? To fix this I can use a big number library, no problem. My Method: var randNum = SHA256( randBigInt(128, 0) ) % 2^64; Where SHA256() is a secure hash function and randBigInt() is defined below as a non-crypto PRNG, im giving it a 128bit seed so brute force shouldn't be a problem. randBigInt(n,s) //return an n-bit random BigInt (n>=1). If s=1, then the most significant of those n bits is set to 1. Is this a secure method to generate a cryptographically secure 64-bit random int? And importantly does taking the 2^64 mod guarantee 100% I have a 64-bit number? An abstract example, say this number is prime (it isn't i know), I will use it in the Galois Field [2^p], where p must be 64bits so that every possible 1-63bit number is a field element. In this query, my random int must be larger than any 63-bit number. And Im not sure im correct in taking the 2^64 mod of a 256bit hash output. Thanks (hope that makes sense)

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  • Problem with sprintf function, last parameters are wrong when written

    - by Apoc
    So I use sprintf sprintf(buffer,"%f|%f|%f|%f|%f|%f|%d|%f|%d", x, y, z, u, v, w, nID,dDistance, nConfig) But when I print the buffer I get the 2 last parameters wrong, they are lets suppose to be 35.0000 and 0 and in the string they are 0.00000 and 10332430 and my buffer is long enough and all the other parameters are good in the string Any idea? Is there a length limit to sprintf or something^ I checked the types of all the numbers and they are right, but what seems to be the problem is the dDistance. When I remove it from the sprint, the nConfig gets the right value in the string, but when I remove nConfig, dDistance still doesn't get the right value. I checked and dDistance is a double. Any idea? Since people don't seem to believe me I did this : char test[255]={0}; int test1 = 2; double test2=35.00; int test3 = 0; sprintf(test,"%d|%f|%d",test1,test2,test3); and I get this in my string: 2|0.000000|1078034432

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  • Download dynamic file with GWT

    - by Maksim
    I have a GWT page where user enter data (start date, end date, etc.), then this data goes to the server via RPC call. On the server I want to generate Excel report with POI and let user save that file on their local machine. This is my test code to stream file back to the client but for some reason I think it does not know how to stream file to the client when I'm using RPC: public class ReportsServiceImpl extends RemoteServiceServlet implements ReportsService { public String myMethod(String s) { File f = new File("/excelTestFile.xls"); String filename = f.getName(); int length = 0; try { HttpServletResponse resp = getThreadLocalResponse(); ServletOutputStream op = resp.getOutputStream(); ServletContext context = getServletConfig().getServletContext(); resp.setContentType("application/octet-stream"); resp.setContentLength((int) f.length()); resp.setHeader("Content-Disposition", "attachment; filename*=\"utf-8''" + filename + ""); byte[] bbuf = new byte[1024]; DataInputStream in = new DataInputStream(new FileInputStream(f)); while ((in != null) && ((length = in.read(bbuf)) != -1)) { op.write(bbuf, 0, length); } in.close(); op.flush(); op.close(); } catch (Exception ex) { ex.printStackTrace(); } return "Server says: " + filename; } } I've red somewhere on internet that you can't do file stream with RPC and I have to use Servlet for that. Is there any example of how to use Servlet and how to call that servlet from ReportsServiceImpl. Do I really need to make a servlet or it is possible to stream it back with my RPC?

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  • Animate and form rows, arrays, AS3

    - by VideoDnd
    Question How can I animate and form rows together? Explanation One 'for loop' is for animation, the other 'for loop' is for making rows. I want to understand how to use arrays and create a row of sprite animations. 'for loop' for animation //FRAMES ARRAY //THIS SETS UP MY ANIMATION FOR TIMER EVENT var frames:Array = [ new Frame1(), new Frame2(), new Frame3(), new Frame4(), new Frame5(), new Frame6(), new Frame7(), new Frame8(), new Frame9(), new Frame0(), ]; for each (var frame:Sprite in frames) { addChild(frame); } 'for loop' for rows //THIS MAKES A ROW OF DISPLAY OBJECTS var numberOfClips:Number = 11; var xStart:Number = 0; var yStart:Number = 0; var xVal:Number = xStart; var xOffset:Number = 2; for (var $:Number=0; $<numberOfClips; $++) { //DUDE ARRAY var dude:Array = frames; dude.y = yStart +11; dude.x = xVal +55; xVal = dude.x + dude.width + this.xOffset; } timer var timer:Timer = new Timer(100); timer.addEventListener(TimerEvent.TIMER, countdown); function countdown(event:TimerEvent) { var currentFrame:int = timer.currentCount % frames.length; for (var i:int = 0; i < frames.length; ++i) { frames[i].visible = (i == currentFrame); } } timer.start(); counter experiment My new class I'm working on loops through 10 different display objects that are numbers. For those following, I'm trying to make something like NumbersView.

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  • Strange Sql Server 2005 behavior

    - by Justin C
    Background: I have a site built in ASP.NET with Sql Server 2005 as it's database. The site is the only site on a Windows Server 2003 box sitting in my clients server room. The client is a local school district, so for data security reasons there is no remote desktop access and no remote Sql Server connection, so if I have to service the database I have to be at the terminal. I do have FTP access to update ASP code. Problem: I was contacted yesterday about an issue with the system. When I looked in to it, it seems a bug that I had solved nearly a year ago had returned. I have a stored procedure that used to take an int as a parameter but a year ago we changed the structure of the system and updated the stored procedure to take an nvarchar(10). The stored procedure somehow changed back to taking an int instead of an nvarchar. There is an external hard drive connected to the server that copies data periodically and has the ability to restore the server in case of failure. I would have assumed that somehow an older version of the database had been restored, but data that I know was inserted 7 days and 1 day before the bug occurred is still in the database. Question: Is there anyway that the structure of a Sql Server 2005 database can revert to a previous version or be restored to a previous version without touching the actual data? No one else should have access to the server so I'm going a little insane trying to figure out how this even happened. Any ideas?

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  • How might I wrap the FindXFile-style APIs to the STL-style Iterator Pattern in C++?

    - by BillyONeal
    Hello everyone :) I'm working on wrapping up the ugly innards of the FindFirstFile/FindNextFile loop (though my question applies to other similar APIs, such as RegEnumKeyEx or RegEnumValue, etc.) inside iterators that work in a manner similar to the Standard Template Library's istream_iterators. I have two problems here. The first is with the termination condition of most "foreach" style loops. STL style iterators typically use operator!= inside the exit condition of the for, i.e. std::vector<int> test; for(std::vector<int>::iterator it = test.begin(); it != test.end(); it++) { //Do stuff } My problem is I'm unsure how to implement operator!= with such a directory enumeration, because I do not know when the enumeration is complete until I've actually finished with it. I have sort of a hack together solution in place now that enumerates the entire directory at once, where each iterator simply tracks a reference counted vector, but this seems like a kludge which can be done a better way. The second problem I have is that there are multiple pieces of data returned by the FindXFile APIs. For that reason, there's no obvious way to overload operator* as required for iterator semantics. When I overload that item, do I return the file name? The size? The modified date? How might I convey the multiple pieces of data to which such an iterator must refer to later in an ideomatic way? I've tried ripping off the C# style MoveNext design but I'm concerned about not following the standard idioms here. class SomeIterator { public: bool next(); //Advances the iterator and returns true if successful, false if the iterator is at the end. std::wstring fileName() const; //other kinds of data.... }; EDIT: And the caller would look like: SomeIterator x = ??; //Construct somehow while(x.next()) { //Do stuff } Thanks! Billy3

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  • where did the _syscallN macros go in <linux/unistd.h>?

    - by Evan Teran
    It used to be the case that if you needed to make a system call directly in linux without the use of an existing library, you could just include <linux/unistd.h> and it would define a macro similar to this: #define _syscall3(type,name,type1,arg1,type2,arg2,type3,arg3) \ type name(type1 arg1,type2 arg2,type3 arg3) \ { \ long __res; \ __asm__ volatile ("int $0x80" \ : "=a" (__res) \ : "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \ "d" ((long)(arg3))); \ if (__res>=0) \ return (type) __res; \ errno=-__res; \ return -1; \ } Then you could just put somewhere in your code: _syscall3(ssize_t, write, int, fd, const void *, buf, size_t, count); which would define a write function for you that properly performed the system call. It seems that this system has been superseded by something (i am guessing that "[vsyscall]" page that every process gets) more robust. So what is the proper way (please be specific) for a program to perform a system call directly on newer linux kernels? I realize that I should be using libc and let it do the work for me. But let's assume that I have a decent reason for wanting to know how to do this :-).

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  • Socket - Adress already in use

    - by Hamza Karmouda
    I'm new to socketand i try to code an Server and client on the same application just to see how it work. here's my code : public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); ((Button)this.findViewById(R.id.bouton1)).setOnClickListener(this); } public void onClick(View v) { TCPServer server = new TCPServer(); TCPClient client = new TCPClient(); server.start(); client.start(); } public class TCPServer extends Thread { @Override public void run() { try { ServerSocket s = new ServerSocket(8080,0,InetAddress.getLocalHost()); Socket cli = s.accept(); byte[] b = new byte[512]; int n; InputStream is = cli.getInputStream(); while((n=is.read(b))>0){ Log.d("TCPServer",new String(b)); if(new String(b).contains("\r\n\r\n"))break; b = new byte[512]; } OutputStream os = cli.getOutputStream(); os.write("Hello".getBytes()); } catch (Exception e) { e.printStackTrace(); } } } public class TCPClient extends Thread { @Override public void run() { try { Socket s = new Socket(InetAddress.getLocalHost().getHostAddress(),8080); //Socket s = new Socket("www.google.com",80); //Log.i("",s.getLocalAddress().getHostAddress()); byte[] b = new byte[512]; int n; if (s.isConnected()) { OutputStream os = s.getOutputStream(); os.write("Hi How are you \r\n\r\n".getBytes()); InputStream is = s.getInputStream(); while((n=is.read(b))>0){ Log.d("TCPClient",new String(b)); b = new byte[512]; } } s.close(); } catch (Exception e) { e.printStackTrace(); } } } the code work fine but just for the first time i click my button. the error is java.net.BindException: Address already in use .

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  • AppFabric caching's local cache isnt working for us... What are we doing wrong?

    - by Olly
    We are using appfabric as the 2ndlevel cache for an NHibernate asp.net application comprising a customer facing website and an admin website. They are both connected to the same cache so when admin updates something, the customer facing site is updated. It seems to be working OK - we have a CacheCLuster on a seperate server and all is well but we want to enable localcache to get better performance, however, it dosnt seem to be working. We have enabled it like this... bool UseLocalCache = int LocalCacheObjectCount = int.MaxValue; TimeSpan LocalCacheDefaultTimeout = TimeSpan.FromMinutes(3); DataCacheLocalCacheInvalidationPolicy LocalCacheInvalidationPolicy = DataCacheLocalCacheInvalidationPolicy.TimeoutBased; if (UseLocalCache) { configuration.LocalCacheProperties = new DataCacheLocalCacheProperties( LocalCacheObjectCount, LocalCacheDefaultTimeout, LocalCacheInvalidationPolicy ); // configuration.NotificationProperties = new DataCacheNotificationProperties(500, TimeSpan.FromSeconds(300)); } Initially we tried using a timeout invalidation policy (3mins) and our app felt like it was running faster. HOWEVER, we noticed that if we changed something in the admin site, it was immediatley updated in the live site. As we are using timeouts not notifications, this demonstrates that the local cache isnt being queried (or is, but is always missing). The cache.GetType().Name returns "LocalCache" - so the factory has made a local cache. Running "Get-Cache-Statistics MyCache" in PS on my dev environment (asp.net app running local from vs2008, cache cluster running on a seperate w2k8 machine) show a handful of Request Counts. However, on the Production environment, the Request Count increases dramaticaly. We tried following the method here to se the cache cliebt-server traffic... http://blogs.msdn.com/b/appfabriccat/archive/2010/09/20/appfabric-cache-peeking-into-client-amp-server-wcf-communication.aspx but the log file had nothing but the initial header in it - i.e no loggin either. I cant find anything in SO or Google. Have we done something wrong? Have we got a screwy install of AppFabric - we installed it via WebPlatform Installer - I think? (note: the IIS box running ASp.net isnt in yhe cluster - it is just the client). Any insights greatfully received!

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  • If a nonblocking recv with MSG_PEEK succeeds, will a subsequent recv without MSG_PEEK also succeed?

    - by Michael Wolf
    Here's a simplified version of some code I'm working on: void stuff(int fd) { int ret1, ret2; char buffer[32]; ret1 = recv(fd, buffer, 32, MSG_PEEK | MSG_DONTWAIT); /* Error handling -- and EAGAIN handling -- would go here. Bail if necessary. Otherwise, keep going. */ /* Can this call to recv fail, setting errno to EAGAIN? */ ret2 = recv(fd, buffer, ret1, 0); } If we assume that the first call to recv succeeds, returning a value between 1 and 32, is it safe to assume that the second call will also succeed? Can ret2 ever be less than ret1? In which cases? (For clarity's sake, assume that there are no other error conditions during the second call to recv: that no signal is delivered, that it won't set ENOMEM, etc. Also assume that no other threads will look at fd. I'm on Linux, but MSG_DONTWAIT is, I believe, the only Linux-specific thing here. Assume that the right fnctl was set previously on other platforms.)

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  • calculate business days including holidays

    - by ran
    i need to calculate the business days between two dates. ex : we have holiday(in USA) on july4th. so if my dates are date1 = 07/03/2012 date2 = 07/06/2012 no of business days b/w these dates should be 1 since july4th is holiday. i have a below method to calclulate the business days which will only counts week ends but not holidays. is there any way to calculate holidays also....please help me on this. public static int getWorkingDaysBetweenTwoDates(Date startDate, Date endDate) { Calendar startCal; Calendar endCal; startCal = Calendar.getInstance(); startCal.setTime(startDate); endCal = Calendar.getInstance(); endCal.setTime(endDate); int workDays = 0; //Return 0 if start and end are the same if (startCal.getTimeInMillis() == endCal.getTimeInMillis()) { return 0; } if (startCal.getTimeInMillis() > endCal.getTimeInMillis()) { startCal.setTime(endDate); endCal.setTime(startDate); } do { startCal.add(Calendar.DAY_OF_MONTH, 1); if (startCal.get(Calendar.DAY_OF_WEEK) != Calendar.SATURDAY && startCal.get(Calendar.DAY_OF_WEEK) != Calendar.SUNDAY) { ++workDays; } } while (startCal.getTimeInMillis() < endCal.getTimeInMillis()); return workDays; }

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  • Are programming languages and methods inefficient? (assembler and C knowledge needed)

    - by b-gen-jack-o-neill
    Hi, for a long time, I am thinking and studying output of C language compiler in assembler form, as well as CPU architecture. I know this may be silly to you, but it seems to me that something is very ineffective. Please, don´t be angry if I am wrong, and there is some reason I do not see for all these principles. I will be very glad if you tell me why is it designed this way. I actually truly believe I am wrong, I know the genius minds of people which get PCs together knew a reason to do so. What exactly, do you ask? I´ll tell you right away, I use C as a example: 1: Stack local scope memory allocation: So, typical local memory allocation uses stack. Just copy esp to ebp and than allocate all the memory via ebp. OK, I would understand this if you explicitly need allocate RAM by default stack values, but if I do understand it correctly, modern OS use paging as a translation layer between application and physical RAM, when address you desire is further translated before reaching actual RAM byte. So why don´t just say 0x00000000 is int a,0x00000004 is int b and so? And access them just by mov 0x00000000,#10? Because you wont actually access memory blocks 0x00000000 and 0x00000004 but those your OS set the paging tables to. Actually, since memory allocation by ebp and esp use indirect addressing, "my" way would be even faster. 2: Variable allocation duplicity: When you run application, Loader load its code into RAM. When you create variable, or string, compiler generates code that pushes these values on the top o stack when created in main. So there is actual instruction for do so, and that actual number in memory. So, there are 2 entries of the same value in RAM. One in form of instruction, second in form of actual bytes in the RAM. But why? Why not to just when declaring variable count at which memory block it would be, than when used, just insert this memory location?

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