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• How can I get the photo saved in Android cell phone in my application

  - by ZHAO Xiaojian

  I want display the images saved in the cell phone in my own application. now I am using MediaStore.Images.Media to do this. I can get the name, size and other information of the images. but i don't know how to get the bitmap? can u help me. thx. There is a method getBitmap(ContentResolver cr, Uri url), but i don't know how to get the Uri of one certain image. thx.

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• maintain dialog center with dynamic content

  - by mcgrailm

  I would have a dialog with the following $("#statusbox").dialog({ autoOpen: false, bgiframe: true, modal: true, width: 'auto', height:'auto', title:"Check Order Status", buttons: { Find: function() { get_status(); }, Close: function() { $(this).dialog('close'); } } }); and when the user hits the find button it runs ajax and returns orders to the dialog and it get dynamically re-sized but it only extends the box down. Is there way to make the box extend up and down so that the dialog remains centered ? also if there was enough content then it could potentially go beyond the bounds of the page so I would think I could use a max height to prevent that but what do I do if they re-size the window ? thanks for any help

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• How to take a screenshot with Mono C#?

  - by vagabond

  I'm trying to use use code get a screenshot in Mono C# but I'm getting a System.NotImplementedException when I call CopyFromScreen. My code works with .NET, so is there an alternate way of getting a screenshot using Mono? Bitmap bitmap = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height); Graphics graphics = Graphics.FromImage(bitmap as Image); graphics.CopyFromScreen(0, 0, 0, 0, bitmap.Size); System.IO.MemoryStream memoryStream = new System.IO.MemoryStream(); bitmap.Save(memoryStream, imageFormat); bitmap.Save(@"\tmp\screenshot.png", ImageFormat.Png); I am using Mono JIT compiler version 2.4.2.3 (Debian 2.4.2.3+dfsg-2)

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• Iterating backward

  - by MBennett

  Suppose I have a vector<int> myvec and I want to loop through all of the elements in reverse. I can think of a few ways of doing this: for (vector<int>::iterator it = myvec.end() - 1; it >= myvec.begin(); --it) { // do stuff here } for (vector<int>::reverse_iterator rit = myvec.rbegin(); rit != myvec.rend(); ++rit) { // do stuff here } for (int i = myvec.size() - 1; i >= 0; --i) { // do stuff here } So my question is when should I use each? Is there a difference? I know that the first one is dangerous because if I pass in an empty vector, then myvec.end() - 1 is undefined, but are there any other hazards or inefficiencies with this?

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• Does the chunk of the System.Collections.Concurrent.Partitioner need to be thread safe?

  - by Scott Chamberlain

  I am working with the Parallel libraries in .net 4 and I am creating a Partitioner and the example shown in the MSDN only has a chunk size of 1 (every time a new result is retrieved it hits the data source instead of the local cache. The version I am writing will pull 10000 SQL rows at a time then feed the rows from the cache until it is empty then pull another batch. Each partition in the Partitioner has its own chunk. I know every time I call to the IEnumerator in from the SQL data-source that needs to be thread safe but for use in a Parallel.ForEach do I need to make every call to the cache for the chunking thread safe?

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• friendship and operator overloading help

  - by sil3nt

  hello there, I have the following class #ifndef Container_H #define Container_H #include <iostream> using namespace std; class Container{ friend bool operator==(const Container &rhs,const Container &lhs); public: void display(ostream & out) const; private: int sizeC; // size of Container int capacityC; // capacity of dynamic array int * elements; // pntr to dynamic array }; ostream & operator<< (ostream & out, const Container & aCont); #endif and this source file #include "container.h" /*----------------------------********************************************* note: to test whether capacityC and sizeC are equal, must i add 1 to sizeC? seeing as sizeC starts off with 0?? */ Container::Container(int maxCapacity){ capacityC = maxCapacity; elements = new int [capacityC]; sizeC = 0; } Container::~Container(){ delete [] elements; } Container::Container(const Container & origCont){ //copy constructor? int i = 0; for (i = 0; i<capacityC; i++){ //capacity to be used here? (*this).elements[i] = origCont.elements[i]; } } bool Container::empty() const{ if (sizeC == 0){ return true; }else{ return false; } } void Container::insert(int item, int index){ if ( sizeC == capacityC ){ cout << "\n*** Next: Bye!\n"; return; // ? have return here? } if ( (index >= 0) && (index <= capacityC) ){ elements[index] = item; sizeC++; } if ( (index < 0) && (index > capacityC) ){ cout<<"*** Illegal location to insert--"<< index << ". Container unchanged. ***\n"; }//error here not valid? according to original a3? have i implemented wrong? } void Container::erase(int index){ if ( (index >= 0) && (index <= capacityC) ){ //correct here? legal location? int i = 0; while (i<capacityC){ //correct? elements[index] = elements[index+1]; //check if index increases here. i++; } sizeC=sizeC-1; //correct? updated sizeC? }else{ cout<<"*** Illegal location to be removed--"<< index << ". Container unchanged. ***\n"; } } int Container::size()const{ return sizeC; //correct? } /* bool Container::operator==(const Container &rhs,const Container &lhs){ int equal = 0, i = 0; for (i = 0; i < capacityC ; i++){ if ( rhs.elements[i] == lhs.elements[i] ){ equal++; } } if (equal == sizeC){ return true; }else{ return false; } } ostream & operator<< (ostream & out, const Container & aCont){ int i = 0; for (i = 0; i<sizeC; i++){ out<< aCont.elements[i] << " " << endl; } } */ I dont have the other functions in the header file (just a quikie). Anyways, the last two functions in "/* */" I cant get to work, what am I doing wrong here? the first function is to see whether the two arrays are equal to one another

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• Default input and output buffering for fopen'd files?

  - by Evan Teran

  So a FILE stream can have both input and output buffers. You can adjust the output stream using setvbuf (I am unaware of any method to play with the input buffer size and behavior). Also, by default the buffer is BUFSIZ (not sure if this is a POSIX or C thing). It is very clear what this means for stdin/stdout/stderr, but what are the defaults for newly opened files? Are they buffered for both input and output? Or perhaps just one? If it is buffered, does output default to block or line mode?

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• How to resize WebView according to its content?

  - by Miraaj

  Hi all, I want to set simple html contents within a web view and then resize it according to its content. To set simple html contents within web view I used this code and it is working fine: [[myWebView mainFrame] loadHTMLString:webViewContents baseURL:baseURLFramed]; Right now, if content is more than its actual size then it appears in web view showing both vertical and horizontal scroller in it. I want to set some default width and manage height according to its content in a way so that neither horizontal nor vertical scroller appears. Can anyone suggest me some solution for it? Thanks, Miraaj

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• GeoDjango: is there an out-of-the-box way to generate clusters of points?

  - by vaughnkoch

  Hi, I'm trying to compute clusters on a set of points in Python, using GeoDjango. The problem: Given a set of points, output a set of clusters of those points. (i'm fine specifying # of clusters/cluster size/distance in advance to simplify) There are a few solutions on the web to do clustering, so it's a well known problem. I thought that GeoDjango would handle these types of problems out of the box, but it's not clear how - I've searched the GeoDjango documentation, Google, and a few other places, but couldn't find anything. Before I roll my own clustering solution, I thought I'd ask to see if there's a straightforward way to do this using GEOS or another package within GeoDjango.

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• CodePlex Daily Summary for Thursday, November 07, 2013

  CodePlex Daily Summary for Thursday, November 07, 2013Popular ReleasesCompare .NET Objects: Version 1.7.4.0: Manual merge of patch 15325 from Farris to fix issues 9075 and 9076 relating to defects with Ignoring the Collection Order Applied patch 15263 from MariuszWojcik to support LINQ enumerators.Toolbox for Dynamics CRM 2011/2013: XrmToolBox (v1.2013.9.25): XrmToolbox improvement Correct changing connection from the status dropdown Tools improvement Updated tool Audit Center (v1.2013.9.10) -> Publish entities Iconator (v1.2013.9.27) -> Optimized asynchronous loading of images and entities MetadataDocumentGenerator (v1.2013.11.6) -> Correct system entities reading with incorrect attribute type Script Manager (v1.2013.9.27) -> Retrieve only custom events SiteMapEditor (v1.2013.11.7) -> Reset of CRM 2013 SiteMap ViewLayoutReplicator (v1.201...Event-Based Components AppBuilder: AB3.AppDesigner.59: Iteration 59 (Feature): By selecting the center thumb of a selected wire you can add a point attribute by context menu (to redirect a wire). Therefore all possible wire outlines are possible... New: AddNewWirePointAttributeFlow, AddNewWirePointAttributeAdapter, NewPointAttributeAdder Improved: LineAdorner, WireLineDecoratorBase, WireLineSourceToTargetDecorator, WiresRenderer, ... See: https://ebcappbuilder.codeplex.com/wikipage?title=Modify%20the%20view%20of%20a%20wire Coming soon: Iterat...Microsoft SQL Server Product Samples: Database: SQL Server 2014 CTP2 In-Memory OLTP Sample, based: This sample showcases the new In-Memory OLTP feature, which is part of SQL Server 2014 CTP2. It shows the new memory-optimized tables and natively-compiled stored procedures, and can be used to show the performance benefit of in-memory OLTP. Installation instructions for the sample are included in the file ‘awinmemsample.doc’, which is part of the download. You can ask a question about this sample at the SQL Server Samples Forum Composite C1 CMS - Open Source on .NET: Composite C1 4.1: Composite C1 4.1 (4.1.5058.34326) Write a review for this release - help us improve, recommend us. Getting started If you are new to Composite C1 and want to install it: http://docs.composite.net/Getting-started What's new in Composite C1 4.1 The following are highlights of major changes since Composite C1 4.0: General user features: Drag-and-drop images and files like PDF and Word directly from own your desktop and folders into page content Allow you to install Composite Form Builder ...xFunc: xFunc 2.10.1: Fixed https://github.com/sys27/xFunc/issues/60.Win_8 (??? Devel Studio 2 ??? 3): Win8 0.8 + Sample (.dvs): ???????------------------------------------------ 1. ????????? ??????????? ????????? ??????. 2. ?????????? ???? , ????????? ? ?????????? ???? ????. 3. ?????????? ?????? ??????. 4. ?????????? ????????? ???????????. 5. ????????????? ??? . English----------------------------------------------------------------------- 1. Added ability to load icons. 2. Fixed bugs related to obtaining names of shapes. 3. Fixed a memory leak. 4. Fixed some defects. 5. Optimized code. ---------------------------...ConEmu - Windows console with tabs: ConEmu 131105 [Alpha]: ConEmu - developer build x86 and x64 versions. Written in C++, no additional packages required. Run "ConEmu.exe" or "ConEmu64.exe". Some useful information you may found: http://superuser.com/questions/tagged/conemu http://code.google.com/p/conemu-maximus5/wiki/ConEmuFAQ http://code.google.com/p/conemu-maximus5/wiki/TableOfContents If you want to use ConEmu in portable mode, just create empty "ConEmu.xml" file near to "ConEmu.exe"CS-Script for Notepad++ (C# intellisense and code execution): Release v1.0.9.0: Implemented Recent Scripts list Added checking for plugin updates from AboutBox Multiple formatting improvements/fixes Implemented selection of the CLR version when preparing distribution package Added project panel button for showing plugin shortcuts list Added 'What's New?' panel Fixed auto-formatting scrolling artifact Implemented navigation to "logical" file (vs. auto-generated) file from output panel To avoid the DLLs getting locked by OS use MSI file for the installation.Home Access Plus+: v9.7: Updated: JSON.net Fixed: Issue with the Windows 8 App Added: Windows 8.1 App Added: Win: Self Signed HAP+ Install Support Added: Win: Delete File Support Added: Timeout for the Logon Tracker Removed: Error Dialogs on the User Card Fixed: Green line showing over the booking form Note: a web.config file update is requiredxUnit.net - Unit testing framework for C# and .NET (a successor to NUnit): xUnit.net Visual Studio Runner: A placeholder for downloading Visual Studio runner VSIX files, in case the Gallery is down (or you want to downgrade to older versions).Social Network Importer for NodeXL: SocialNetImporter(v.1.9.1): This new version includes: - Include me option is back - Fixed the login bug reported latelyVeraCrypt: VeraCrypt version 1.0c: Changes between 1.0b and 1.0c (11 November 2013) : Set correctly the minimum required version in volumes header (this value must always follow the program version after any major changes). This also solves also the hidden volume issueCaptcha MVC: Captcha MVC 2.5: v 2.5: Added support for MVC 5. The DefaultCaptchaManager is no longer throws an error if the captcha values was entered incorrectly. Minor changes. v 2.4.1: Fixed issues with deleting incorrect values of the captcha token in the SessionStorageProvider. This could lead to a situation when the captcha was not working with the SessionStorageProvider. Minor changes. v 2.4: Changed the IIntelligencePolicy interface, added ICaptchaManager as parameter for all methods. Improved font size ...Duplica: duplica 0.2.498: this is first stable releaseDNN Blog: 06.00.01: 06.00.01 ReleaseThis is the first bugfix release of the new v6 blog module. These are the changes: Added some robustness in v5-v6 scripts to cater for some rare upgrade scenarios Changed the name of the module definition to avoid clash with Evoq Social Addition of sitemap providerVG-Ripper & PG-Ripper: VG-Ripper 2.9.50: changes NEW: Added Support for "ImageHostHQ.com" links NEW: Added Support for "ImgMoney.net" links NEW: Added Support for "ImgSavy.com" links NEW: Added Support for "PixTreat.com" links Bug fixesVidCoder: 1.5.11 Beta: Added Encode Details window. Exposes elapsed time, ETA, current and average FPS, running file size, current pass and pass progress. Open it by going to Windows -> Encode Details while an encode is running. Subtitle dialog now disables the "Burn In" checkbox when it's either unavailable or it's the only option. It also disables the "Forced Only" when the subtitle type doesn't support the "Forced" flag. Updated HandBrake core to SVN 5872. Fixed crash in the preview window when a source fil...Wsus Package Publisher: Release v1.3.1311.02: Add three new Actions in Custom Updates : Work with Files (Copy, Delete, Rename), Work with Folders (Add, Delete, Rename) and Work with Registry Keys (Add, Delete, Rename). Fix a bug, where after resigning an update, the display is not refresh. Modify the way WPP sort rows in 'Updates Detail Viewer' and 'Computer List Viewer' so that dates are correctly sorted. Add a Tab in the settings form to set Proxy settings when WPP needs to go on Internet. Fix a bug where 'Manage Catalogs Subsc...uComponents: uComponents v6.0.0: This release of uComponents will compile against and support the new API in Umbraco v6.1.0. What's new in uComponents v6.0.0? New DataTypesImage Point XML DropDownList XPath Templatable List New features / Resolved issuesThe following workitems have been implemented and/or resolved: 14781 14805 14808 14818 14854 14827 14868 14859 14790 14853 14790 DataType Grid 14788 14810 14873 14833 14864 14855 / 14860 14816 14823 Drag & Drop support for rows Su...New ProjectsAuto Mapping MVVM: A simple MVVM Kit that works with Windows 8 and Windows Phone 8, with the ability to automatically map between Views and ViewModels.BMS Converter: BMS Converter is a converter for .bms files (Be-Music Source), which converts them to audio and/or video files.Car Management: The software which is going to be developed aims to give an interface in order to manage cars booking with ABC University institution.Classic Algorithms: This is a collection of classic algorithms written in C#. I'll start with the Graphs.Community TFS Work Item Tracking Extensions: The Community TFS WIT Extensions project is a place to share tools and extensions to the TFS work item tracking system.D3N: "port" of D3 to .NETdoinik tara client: The Daily Star ClientLEGO MINDSTORMS EV3 API: API for the LEGO Mindstorms EV3 brick usable from desktop, Windows Phone and WinRT.LudejoWcf: Playground wcfMy Test: This is a demoPearson API Wrapper: Pearson API Wrapper enables you to develop Learning Apps faster !Pescar2013ShopAyelenArce: Lalalapescar2013-shop-ElectroShop: ya contiene: EF5 agrega: layouts bootstrap bootstrap js js linq(?) knockout(?) jquery jquery ui Pescar2013Shop-MaruMati: Venta de productos a través de una pagina web.Pescar2013Shop-The_Future_2014: primer proyecto.RatatoskSMS: SMS gateway based on library GSMComm, that can handle multiple GSM modems to send and recieve messages to/from database, with http interface.SharePoint Enhanced New: A replacement to the "New Document" split button in document libraries with a modal dialog displaying available document Content Types.Task Management Application: The Eisenhower Matrix with BacklogTridion: This project provides an analog to Tridion Core Services for older versions of Tridion that rely on the TOM (COM) architecture.Web Scripting - Assignment 2 - Website Prototype: Assignment 2 - Website PrototypeWindows Azure Custom Performance Counters: The project Windows Azure Custom Performance Counters is a startup task to help working with custom performance counters on web and worker roles.

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• ASP.NET connection pool question

  - by James Evans

  Does the same connection string used on two different physical servers hosting different web applications that talk to the same database draw connections from the same connection pool? Or are pooled connections confined to at the application level? I ask because I inherited a 7 year old .NET 1.1 web application which is riddled with in-line SQL, unclosed and undisposed sql connection and datareader objects. Recently, I was tasked to write a small web app that is hosted on another server and talks to the same database and therefore used the same database connection string. I created a LINQ object to read and write the one table required by the app. Now the original .NET 1.1 app is throwing exceptions like "Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached." Maybe these are unreleated, but wanted to get your opinions to make sure I cover all my bases. Thanks!

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• How to close the Facebook pop-up login window after the user Connects?

  - by alex

  Below is my code. For some reason, after the user logs into the little pop-up window, the little window will redirect back to '/" with a lot of session JSON junk at the end of the URL. How do I make it so that the little window closes, and my parent window refreshes? <script src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/FeatureLoader.js.php/en_US" type="text/javascript"></script> <fb:login-button v="2" onlogin='window.location("/test");' size="medium">Connect</fb:login-button> <script type="text/javascript">FB.init("XXXXX",'/xd_receiver.htm');</script>

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• java.io.IOException: Invalid argument

  - by Luixv

  Hi I have a web application running in cluster mode with a load balancer. It consists in two tomcats (T1, and T2) addressing only one DB. T2 is nfs mounted to T1. This is the only dofference between both nodes. I have a java method generating some files. If the request runs on T1 there is no problem but if the request is running on node 2 I get an exception as follows: java.io.IOException: Invalid argument at java.io.FileOutputStream.close0(Native Method) at java.io.FileOutputStream.close(FileOutputStream.java:279) The corresponding code is as follows: for (int i = 0; i < dataFileList.size(); i++) { outputFileName = outputFolder + fileNameList.get(i); FileOutputStream fileOut = new FileOutputStream(outputFileName); fileOut.write(dataFileList.get(i), 0, dataFileList.get(i).length); fileOut.flush(); fileOut.close(); } The exception appears at the fileOut.close() Any hint? Luis

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• How do I create regex groups for replacement?

  - by resting

  I have this sample string: Image: SGD$45.32 SKU: 3f3f3 dfdfd grg4t BP 6yhf Pack Size: 1000's Color: Green Price: SGD$45.32 SGD$45... I would like to remove all the prices namely: SGD$45.32 Price: SGD$45.32 SGD$45 I have this expression thats supposed to match the 3 groups: $pattern = '/(Price.+\sSGD\$\d+\.\d{2})(SGD\$\d+\.\d{2})(SGD\$\d+)/'; $new_snippet = preg_replace($pattern, '', $snippet);` But apparently its not working. It works if I replace a single group at a time. But, I'd like to know if it possible to replace all possible matching groups with a single statement. Tried preg_match_all($pattern, $snippet, $matches); to show matches based on the above pattern, but no matches are found if I put all 3 groups together.

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• java.util.BitSet -- set() doesn't work as expected

  - by dwhsix

  Am I missing something painfully obvious? Or does just nobody in the world actually use java.util.BitSet? The following test fails: @Test public void testBitSet() throws Exception { BitSet b = new BitSet(); b.set(0, true); b.set(1, false); assertEquals(2, b.length()); } It's really unclear to me why I don't end up with a BitSet of length 2 and the value 10. I peeked at the source for java.util.BitSet, and on casual inspection it seems to fail to make sufficient distinction between a bit that's been set false and a bit that has never been set to any value... (Note that explicitly setting the size of the BitSet in the constructor has no effect, e.g.: BitSet b = new BitSet(2);

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• Problems wih minSdkVersion 1.5

  - by Tebam

  Hello, we have a problem related to the manifest file and the property "android:minSdkVersion". The issue is: If our platform is 2.0 and we use the property "android:minSdkVersion=3" (3 = sdk 1.5) the graphics get corrupted (In details, the application's resolution get reduced to a 2/3 part of the original size, this is, when the resolution should be 480x720, it becomes in a 320x480). This is happening on the Android emulator, and on the devices Droid/Milestone (Which are platforms 2.0). When we switch the property to "android:minSdkVersion=4" (4 = sdk 1.6) the problem gets solved, but when we want to put that version on platform 1.5, Android doesn't allow us to install it. It would help us to know any conflict regarding graphics within the 2.0 sdk, or any known problem around the "android:minSdkVersion" in the manifest. Thanks!

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• Easiest way of checking if a string consists of unique characters?

  - by serg555

  I need to check in Java if a word consists of unique letters (case insensitive). As straight solution is boring, I came up with: For every char in a string check if indexOf(char) == lastIndexOf(char). Add all chars to HashSet and check if set size == string length. Convert a string to a char array, sort it alphabetically, loop through array elements and check if c[i] == c[i+1]. Currently I like #2 the most, seems like the easiest way. Any other interesting solutions?

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• Working with images in WCF

  - by hgulyan

  Hi, I have a desktop application that needs to upload/download images to/from service computer over TCP Protocol. At first, I stored images in file system, but I need to in MS SQL DB to compare which solution is better. Number of images is over half a million. I don't know yet will there be any limitation on size of a photo. If you have done smth like that, please, write what your opinion upon this question. Which one is faster, more safe? Which of them works better with this number of photos? If I'll store on DB, do I need to store images apart from all other tables which I use for my application and which type works better - image or varbinary on DB?..and so on. Thank you.

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• Safari ignores input type="file" on server post

  - by Jon

  I have a real problem with a classic ASP page. The page allows the user to upload a document and save it to the database. The intial page posts to another asp page which saves down to the db. This works on IE and Firefox. However on Safari it fails. I've debugged the problem and it boils down to the fact that of all the controls that the server page has access to, only 1 control is missing. This happens to be this: <input type="file" size="40" id="myfile" name="myfile" /> So I'm wondering why safari would decide to not give me access to this control (using asp's Request("") ) and why it works in FF and IE. I have some debug code which writes out all controls and it doesn't see this control. p.s. I hate Web development

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• How to assign permissions for Copy/Paste on windows

  - by jalchr

  Well, as everyone knows there is no way you can assign permissions for Copy/Paste of files on windows platform. I need to control the copy process from a central file server, in a way that helps me know: which user performed the copy Which files were copied where did he pasted them Total size of data copied Time of copy operation If user exceeds the allowed "Copy-Limit", a dialog box requests him to enter administrative credentials or deny him (as it would be configured) Store all this data in a file for later review or send by email. I need to collect this data by putting a utility program on the server itself, without any other installation on client computers. I know about monitoring the Clipboard, but which clipboard would it be? the user's clipboard or the server's clipboard ? And what about drag-drop operation, which doesn't even pass through the clipboard? Any knowledge of whether SystemFileWatcher is useful in such case ? Any ideas ?

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• .NET Code Evolution

  - by Alois Kraus

  Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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• How to use less memory while running a task in Symfony 1.4?

  - by Guillaume Flandre

  I'm using Symfony 1.4 and Doctrine. So far I had no problem running tasks with Symfony. But now that I have to import a pretty big amount of data and save them in the database, I get the infamous "Fatal Error: Allowed memory size of XXXX bytes exhausted" During this import I'm only creating new objects, setting a few fields and saving them. I'm pretty sure it has something to do with the number of objects I'm creating when saving data. Unsetting those objects doesn't do anything though. Are there any best practices to limit memory usage in Symfony?

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• C# and Linq: Generating SQL Backup/Restore From Code

  - by mdvaldosta

  I'm working with a C# and Linq to SQL Winforms app and needed to integrate backup and restores through the program. I used SMO and got it working pretty smoothly. The issue, however, is that the app is deployed using ClickOnce, which I like very much - but since I had to include the dll's the download size jumped from 3mb = 15mb. I know they've only got to download it once, but it also sucks for me as Visual Studio 2010 seems to upload the dll's every time and that takes a while on AT&T broadband (eh). So, anyone have any suggestion on how I can work out an effective backup/restore solution without using SMO objects?

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• How to recognize whether a web site is opened in a mobile or a PC

  - by Yogi Yang 007

  We have a site developed in PHP. It is working just fine. We have used JQuery for every kind of situation like slide shows, menus, etc. This site contains a lot of images which are large in size. because of this when viewed in a mobile phone user has to scroll a lot. How can we recognize whether the client (browser) trying to access our site is a mobile phone or a standard PC. Is there any standard way to build site for such situations? TIA

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• UITextView like iPhone Notes application

  - by Mark

  I am trying to recreate the Notes application. So far I got the following: textView = [[UITextView alloc] initWithFrame:CGRectMake(25.0, 30.0, 295.0, 214.0)]; textView.delegate = self; textView.backgroundColor = [UIColor clearColor]; textView.font = [UIFont fontWithName:@"MarkerFelt-Thin" size:19.0]; [self.view addSubview:textView]; The thing I dont know is how they were able to put the date on top like a header (it is within the UIScrollView that is obvious). Also under every text there is a line where did that came from. Does someone have an idea or a sample project I can take a look at?

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