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  • Interesting articles and blogs on SPARC T4

    - by mv
    Interesting articles and blogs on SPARC T4 processor   I have consolidated all the interesting information I could get on SPARC T4 processor and its hardware cryptographic capabilities.  Hope its useful. 1. Advantages of SPARC T4 processor  Most important points in this T4 announcement are : "The SPARC T4 processor was designed from the ground up for high speed security and has a cryptographic stream processing unit (SPU) integrated directly into each processor core. These accelerators support 16 industry standard security ciphers and enable high speed encryption at rates 3 to 5 times that of competing processors. By integrating encryption capabilities directly inside the instruction pipeline, the SPARC T4 processor eliminates the performance and cost barriers typically associated with secure computing and makes it possible to deliver high security levels without impacting the user experience." Data Sheet has more details on these  : "New on-chip Encryption Instruction Accelerators with direct non-privileged support for 16 industry-standard cryptographic algorithms plus random number generation in each of the eight cores: AES, Camellia, CRC32c, DES, 3DES, DH, DSA, ECC, Kasumi, MD5, RSA, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512" I ran "isainfo -v" command on Solaris 11 Sparc T4-1 system. It shows the new instructions as expected  : $ isainfo -v 64-bit sparcv9 applications crc32c cbcond pause mont mpmul sha512 sha256 sha1 md5 camellia kasumi des aes ima hpc vis3 fmaf asi_blk_init vis2 vis popc 32-bit sparc applications crc32c cbcond pause mont mpmul sha512 sha256 sha1 md5 camellia kasumi des aes ima hpc vis3 fmaf asi_blk_init vis2 vis popc v8plus div32 mul32  2.  Dan Anderson's Blog have some interesting points about how these can be used : "New T4 crypto instructions include: aes_kexpand0, aes_kexpand1, aes_kexpand2,         aes_eround01, aes_eround23, aes_eround01_l, aes_eround_23_l, aes_dround01, aes_dround23, aes_dround01_l, aes_dround_23_l.       Having SPARC T4 hardware crypto instructions is all well and good, but how do we access it ?      The software is available with Solaris 11 and is used automatically if you are running Solaris a SPARC T4.  It is used internally in the kernel through kernel crypto modules.  It is available in user space through the PKCS#11 library." 3.   Dans' Blog on Where's the Crypto Libraries? Although this was written in 2009 but still is very useful  "Here's a brief tour of the major crypto libraries shown in the digraph:   The libpkcs11 library contains the PKCS#11 API (C_\*() functions, such as C_Initialize()). That in turn calls library pkcs11_softtoken or pkcs11_kernel, for userland or kernel crypto providers. The latter is used mostly for hardware-assisted cryptography (such as n2cp for Niagara2 SPARC processors), as that is performed more efficiently in kernel space with the "kCF" module (Kernel Crypto Framework). Additionally, for Solaris 10, strong crypto algorithms were split off in separate libraries, pkcs11_softtoken_extra libcryptoutil contains low-level utility functions to help implement cryptography. libsoftcrypto (OpenSolaris and Solaris Nevada only) implements several symmetric-key crypto algorithms in software, such as AES, RC4, and DES3, and the bignum library (used for RSA). libmd implements MD5, SHA, and SHA2 message digest algorithms" 4. Difference in T3 and T4 Diagram in this blog is good and self explanatory. Jeff's blog also highlights the differences  "The T4 servers have improved crypto acceleration, described at https://blogs.oracle.com/DanX/entry/sparc_t4_openssl_engine. It is "just built in" so administrators no longer have to assign crypto accelerator units to domains - it "just happens". Every physical or virtual CPU on a SPARC-T4 has full access to hardware based crypto acceleration at all times. .... For completeness sake, it's worth noting that the T4 adds more crypto algorithms, and accelerates Camelia, CRC32c, and more SHA-x." 5. About performance counters In this blog, performance counters are explained : "Note that unlike T3 and before, T4 crypto doesn't require kernel modules like ncp or n2cp, there is no visibility of crypto hardware with kstats or cryptoadm. T4 does provide hardware counters for crypto operations.  You can see these using cpustat: cpustat -c pic0=Instr_FGU_crypto 5 You can check the general crypto support of the hardware and OS with the command "isainfo -v". Since T4 crypto's implementation now allows direct userland access, there are no "crypto units" visible to cryptoadm.  " For more details refer Martin's blog as well. 6. How to turn off  SPARC T4 or Intel AES-NI crypto acceleration  I found this interesting blog from Darren about how to turn off  SPARC T4 or Intel AES-NI crypto acceleration. "One of the new Solaris 11 features of the linker/loader is the ability to have a single ELF object that has multiple different implementations of the same functions that are selected at runtime based on the capabilities of the machine.   The alternate to this is having the application coded to call getisax(2) system call and make the choice itself.  We use this functionality of the linker/loader when we build the userland libraries for the Solaris Cryptographic Framework (specifically libmd.so and libsoftcrypto.so) The Solaris linker/loader allows control of a lot of its functionality via environment variables, we can use that to control the version of the cryptographic functions we run.  To do this we simply export the LD_HWCAP environment variable with values that tell ld.so.1 to not select the HWCAP section matching certain features even if isainfo says they are present.  This will work for consumers of the Solaris Cryptographic Framework that use the Solaris PKCS#11 libraries or use libmd.so interfaces directly.  For SPARC T4 : export LD_HWCAP="-aes -des -md5 -sha256 -sha512 -mont -mpul" .. For Intel systems with AES-NI support: export LD_HWCAP="-aes"" Note that LD_HWCAP is explained in  http://docs.oracle.com/cd/E23823_01/html/816-5165/ld.so.1-1.html "LD_HWCAP, LD_HWCAP_32, and LD_HWCAP_64 -  Identifies an alternative hardware capabilities value... A “-” prefix results in the capabilities that follow being removed from the alternative capabilities." 7. Whitepaper on SPARC T4 Servers—Optimized for End-to-End Data Center Computing This Whitepaper on SPARC T4 Servers—Optimized for End-to-End Data Center Computing explains more details.  It has DTrace scripts which may come in handy : "To ensure the hardware-assisted cryptographic acceleration is configured to use and working with the security scenarios, it is recommended to use the following Solaris DTrace script. #!/usr/sbin/dtrace -s pid$1:libsoftcrypto:yf*:entry, pid$target:libsoftcrypto:rsa*:entry, pid$1:libmd:yf*:entry { @[probefunc] = count(); } tick-1sec { printa(@ops); trunc(@ops); }" Note that I have slightly modified the D Script to have RSA "libsoftcrypto:rsa*:entry" as well as per recommendations from Chi-Chang Lin. 8. References http://www.oracle.com/us/corporate/features/sparc-t4-announcement-494846.html http://www.oracle.com/us/products/servers-storage/servers/sparc-enterprise/t-series/sparc-t4-1-ds-487858.pdf https://blogs.oracle.com/DanX/entry/sparc_t4_openssl_engine https://blogs.oracle.com/DanX/entry/where_s_the_crypto_libraries https://blogs.oracle.com/darren/entry/howto_turn_off_sparc_t4 http://docs.oracle.com/cd/E23823_01/html/816-5165/ld.so.1-1.html   https://blogs.oracle.com/hardware/entry/unleash_the_power_of_cryptography https://blogs.oracle.com/cmt/entry/t4_crypto_cheat_sheet https://blogs.oracle.com/martinm/entry/t4_performance_counters_explained  https://blogs.oracle.com/jsavit/entry/no_mau_required_on_a http://www.oracle.com/us/products/servers-storage/servers/sparc-enterprise/t-series/sparc-t4-business-wp-524472.pdf

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  • CodePlex Daily Summary for Tuesday, March 23, 2010

    CodePlex Daily Summary for Tuesday, March 23, 2010New Projects.NET StarCraft II Replay Parser: A .NET 3.5 Library used to parse StarCraft II replays. Developed in C# 3.5.BackToBasics "B2B" Chat: With technology and software getting more and more complicated, why not get back to basics with BackToBasicsChat. B2B allows you to chat over a ser...Dark Neuron Game Engine: Dark Neuron allows you to easily create fun and interesting games with no need of developing basic game components. This engine is developed for C#...DeepZoom Pivot Constructor: Library to make building DeepZoom images and Pivot displays simpler.ePaper reader: The project is aimed at creating a tool which helps in reading electronic editions of news papers(pdf/flash)FSharpPageProvider for EPiServer CMS 6: This project starts as the port of EPiServer XmlPageProvider to F# programming language. Hammock for REST: Hammock is a REST library for .NET that greatly simplifies consuming and wrapping RESTful services.Kirill Osenkov: Various small projects, tools, utilities and samples by Kirill OsenkovliveDB: liveDB - web client for sql serverLucilla Framework: lucilla frameworkMVC Foolproof Validation: MVC Foolproof Validation aims to extend the Data Annotation validation provided in ASP.NET MVC. Initial efforts are focused on adding contingent va...MVC2Forums: MVC2Forums is simply a forum system based upon MVC2.Mvvm Foundation Silverlight: Mvvm Foundation Silverlight is a library of classes that are helpful when building Silverlight applications based in the MVVM pattern. This librar...MyPersonalWebsite: This is my personal web site developed using ASP.NET MVC 2Planner: Planner makes it easier for all peoples to plan your tasks. It's developed in Delphi.Prose: Prose is an playground for an experimental JavaScript like language compiler. Eventually it will implement 0-CFA, CFA2, and a Tracing JITQuestTracker: QuestTracker is a todo list presented in the format of a quest tracking list such as the one in World of Warcraft.SevenZipLib: SevenZipLib is a C# interface to the 7-zip library.SimpleGeo .Net: .Net Client library for the SimpleGeo.com serviceNew ReleasesAutenticar no OpenLDAP utilizando pGIna: DLL LDAPAuth Plus: New Group: No LoginBMap.NET: BMap.NET 2: This is the 2nd version of BMap.NET. It has included these tags: Bing Maps, and "About BMap.NET".Cronos: Version 2.04: This is primarily a bug-fix release. Several numerical issues have been resolved, and a resource leak (of MS Windows graphics objects) has been fi...EV Dashboard: v1.0: This release includes support for an App.config file and Auto Connect, which will connect to the specified BMS at startup. Note: You still have to ...GKO Libraries: GKO Libraries 0.1 Beta: 0.1 Beta Added More utilities and functions RefactoringsGLB Virtual Player Builder: 0.4.2 Beta: Beta build that includes a new player creator.HKGolden Express: HKGoldenExpress (Build 201003222215): New features: (None) Bug fix: Fixed bugs of unable to parse XML file stream returned from HKGolden API, as the encoding of XML file stream chang...jQuery Web Controls ASP.Net: jQueryWebControls 1.1.1.2: En esta versión se han corregido problemas existentes en la ejecución de los scripts de jquery cuando se utilizaban MasterPage y/o Ajax Control Too...LightKit: Version 0.2.2: Fixed: fixed bug when CollectionItemsEditor ditermines IsChanged property incorrectly fixed ObjectEditor`a thisstring propertyName method wrong l...LINQ to Twitter: LINQ to Twitter Beta v2.0.8: New items added since v1.1 include: Support for OAuth (via DotNetOpenAuth), secure communication via https, VB language support, serialization of ...MapWindow6: MapWindow 6.0 msi (March 22): This version fixes the icons for the desktop installer and changes the install directory to Program Files\MapWindow instead of Program Files\ISU.Math.NET Numerics: 2010.3.22.1334 Build: Latest alpha buildMiniCalendar Web Part: MiniCalendar Web Part 1.8: A small web part to display links to events stored in a list (or document library) in a mini calendar (in month view mode). It shows tooltips for t...OCInject: Release Two: This release brings some missing features such as Singleton support, Func<T> factories and child containers. It, also, has an updated constructor ...Phalanger - The PHP Language Compiler for the .NET Framework: 2.0 (March 2010): Installer of the latest binaries of Phalanger 2.0 (March 2010) and its integration into Visual Studio 2008. Easy installer with automatic IIS int...Planner: Planner: firstQuestTracker: QuestTracker 0.1: This is the preliminary release of QuestTracker. There's not much documentation or many features yet, but it is functional. Any feedback would be a...QuestTracker: QuestTracker 0.1.1: Bugfix for QuestTracker 0.1QuestTracker: QuestTracker 0.1.2: Fixes an issue with saving the quest list.Rawr: Rawr 2.3.13: We're pleased to announce that, after long last, Rawr3 has entered public beta. You're still welcome to continue using Rawr2 (that's what you're re...Single Web Session: Alpha Model Plugin: !How to use Single Web Session add following line into your web config <httpModules> <add name="SingleSession" type="SingleWebSession.Model.W...SMIL - SharePoint Map Integration Layer: SMIL 1.0: Custom data field Extracts Lat/Lon from EXIF from images being uploaded. Map Web Part Filter with SharePoint views Filter by connecting to...sTASKedit: sTASKedit 42532 (Developer Alpha): This release is only to verify the currently decoded task structure... Supported files: tasks.data (v1.3.6 client)VCC: Latest build, v2.1.30322.0: Automatic drop of latest buildVisual Studio DSite: Advanced Notepad (Visual C++ 2008): An notepad written in c that can save in a rich text file format.Wallpaper Rotator: Wallpaper Rotator 0.5: Wallpaper Rotator 0.5 This version includes the following improvements: Saving the choice of "Random Order (Shuffle Mode)" Updating the configu...Most Popular ProjectsMetaSharpRawrWBFS ManagerSilverlight ToolkitASP.NET Ajax LibraryMicrosoft SQL Server Product Samples: DatabaseAJAX Control ToolkitLiveUpload to FacebookWindows Presentation Foundation (WPF)ASP.NETMost Active ProjectsRawrjQuery Library for SharePoint Web ServicesBlogEngine.NETLINQ to TwitterPHPExcelFarseer Physics EngineFacebook Developer ToolkitNB_Store - Free DotNetNuke Ecommerce Catalog Modulepatterns & practices: Composite WPF and SilverlightN2 CMS

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  • Developing Mobile Applications: Web, Native, or Hybrid?

    - by Michelle Kimihira
    Authors: Joe Huang, Senior Principal Product Manager, Oracle Mobile Application Development Framework  and Carlos Chang, Senior Principal Product Director The proliferation of mobile devices and platforms represents a game-changing technology shift on a number of levels. Companies must decide not only the best strategic use of mobile platforms, but also how to most efficiently implement them. Inevitably, this conversation devolves to the developers, who face the task of developing and supporting mobile applications—not a simple task in light of the number of devices and platforms. Essentially, developers can choose from the following three different application approaches, each with its own set of pros and cons. Native Applications: This refers to apps built for and installed on a specific platform, such as iOS or Android, using a platform-specific software development kit (SDK).  For example, apps for Apple’s iPhone and iPad are designed to run specifically on iOS and are written in Xcode/Objective-C. Android has its own variation of Java, Windows uses C#, and so on.  Native apps written for one platform cannot be deployed on another. Native apps offer fast performance and access to native-device services but require additional resources to develop and maintain each platform, which can be expensive and time consuming. Mobile Web Applications: Unlike native apps, mobile web apps are not installed on the device; rather, they are accessed via a Web browser.  These are server-side applications that render HTML, typically adjusting the design depending on the type of device making the request.  There are no program coding constraints for writing server-side apps—they can be written in Java, C, PHP, etc., it doesn’t matter.  Instead, the server detects what type of mobile browser is pinging the server and adjusts accordingly. For example, it can deliver fully JavaScript and CSS-enabled content to smartphone browsers, while downgrading gracefully to basic HTML for feature phone browsers. Mobile apps work across platforms, but are limited to what you can do through a browser and require Internet connectivity. For certain types of applications, these constraints may not be an issue. Oracle supports mobile web applications via ADF Faces (for tablets) and ADF Mobile browser (Trinidad) for smartphone and feature phones. Hybrid Applications: As the name implies, hybrid apps combine technologies from native and mobile Web apps to gain the benefits each. For example, these apps are installed on a device, like their pure native app counterparts, while the user interface (UI) is based on HTML5.  This UI runs locally within the native container, which usually leverages the device’s browser engine.  The advantage of using HTML5 is a consistent, cross-platform UI that works well on most devices.  Combining this with the native container, which is installed on-device, provides mobile users with access to local device services, such as camera, GPS, and local device storage.  Native apps may offer greater flexibility in integrating with device native services.  However, since hybrid applications already provide device integrations that typical enterprise applications need, this is typically less of an issue.  The new Oracle ADF Mobile release is an HTML5 and Java hybrid framework that targets mobile app development to iOS and Android from one code base. So, Which is the Best Approach? The short answer is – the best choice depends on the type of application you are developing.  For instance, animation-intensive apps such as games would favor native apps, while hybrid applications may be better suited for enterprise mobile apps because they provide multi-platform support. Just for starters, the following issues must be considered when choosing a development path. Application Complexity: How complex is the application? A quick app that accesses a database or Web service for some data to display?  You can keep it simple, and a mobile Web app may suffice. However, for a mobile/field worker type of applications that supports mission critical functionality, hybrid or native applications are typically needed. Richness of User Interactivity: What type of user experience is required for the application?  Mobile browser-based app that’s optimized for mobile UI may suffice for quick lookup or productivity type of applications.  However, hybrid/native application would typically be required to deliver highly interactive user experiences needed for field-worker type of applications.  For example, interactive BI charts/graphs, maps, voice/email integration, etc.  In the most extreme case like gaming applications, native applications may be necessary to deliver the highly animated and graphically intensive user experience. Performance: What type of performance is required by the application functionality?  For instance, for real-time look up of data over the network, mobile app performance depends on network latency and server infrastructure capabilities.  If consistent performance is required, data would typically need to be cached, which is supported on hybrid or native applications only. Connectivity and Availability: What sort of connectivity will your application require? Does the app require Web access all the time in order to always retrieve the latest data from the server? Or do the requirements dictate offline support? While native and hybrid apps can be built to operate offline, Web mobile apps require Web connectivity. Multi-platform Requirements: The terms “consumerization of IT” and BYOD (bring your own device) effectively mean that the line between the consumer and the enterprise devices have become blurred. Employees are bringing their personal mobile devices to work and are often expecting that they work in the corporate network and access back-office applications.  Even if companies restrict access to the big dogs: (iPad, iPhone, Android phones and tablets, possibly Windows Phone and tablets), trying to support each platform natively will require increasing resources and domain expertise with each new language/platform. And let’s not forget the maintenance costs, involved in upgrading new versions of each platform.   Where multi-platform support is needed, Web mobile or hybrid apps probably have the advantage. Going native, and trying to support multiple operating systems may be cost prohibitive with existing resources and developer skills. Device-Services Access:  If your app needs to access local device services, such as the camera, contacts app, accelerometer, etc., then your choices are limited to native or hybrid applications.   Fragmentation: Apple controls Apple iOS and the only concern is what version iOS is running on any given device.   Not so Android, which is open source. There are many, many versions and variants of Android running on different devices, which can be a nightmare for app developers trying to support different devices running different flavors of Android.  (Is it an Amazon Kindle Fire? a Samsung Galaxy?  A Barnes & Noble Nook?) This is a nightmare scenario for native apps—on the other hand, a mobile Web or hybrid app, when properly designed, can shield you from these complexities because they are based on common frameworks.  Resources: How many developers can you dedicate to building and supporting mobile application development?  What are their existing skills sets?  If you’re considering native application development due to the complexity of the application under development, factor the costs of becoming proficient on a each platform’s OS and programming language. Add another platform, and that’s another language, another SDK. On the other side of the equation, Web mobile or hybrid applications are simpler to make, and readily support more platforms, but there may be performance trade-offs. Conclusion This only scratches the surface. However, I hope to have suggested some food for thought in choosing your mobile development strategy.  Do your due diligence, search the Web, read up on mobile, talk to peers, attend events. The development team at Oracle is working hard on mobile technologies to help customers extend enterprise applications to mobile faster and effectively.  To learn more on what Oracle has to offer, check out the Oracle ADF Mobile (hybrid) and ADF Faces/ADF Mobile browser (Web Mobile) solutions from Oracle.   Additional Information Blog: ADF Blog Product Information on OTN: ADF Mobile Product Information on Oracle.com: Oracle Fusion Middleware Follow us on Twitter and Facebook Subscribe to our regular Fusion Middleware Newsletter

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  • What are the best open-source software non-profits for making financial contributions and/or facilitating useful work?

    - by Jason S
    I'm not a great programmer myself (my main job is more electrical engineering) and have never really helped out with any open source projects, but I've benefited greatly from free and/or open-source software (MySQL, OpenOffice, Firefox, Apache, PHP, Java, etc.) and at some point would like to make some modest financial contributions to help keep this stuff going. I'm wondering, what are the best non-profits to make financial contributions? I'm aware of: Open Source Initiative (founded 10 years ago by several prominent figures including programmer and "The Cathedral and the Bazaar" author Eric S. Raymond) Free Software Foundation Mozilla Foundation Apache Foundation Anyone have a particular favorite? Ideally I'd like to give money to a non-profit that would foster some of the smaller but promising open-source and/or free software projects. The big projects like Firefox and Apache are already well-established. There are a few small individual shareware programs I've already paid for directly. But it's those middle-ground projects that I would really like my contributions to support. (one that comes to mind is a good GUI for Subversion or Mercurial.) It's one thing for a single person to donate a little $$ to a small project. It's another for a foundation or something to give larger grants to projects that give a good bang for the buck. Conservation organizations like The Nature Conservancy, or the Trust for Public Lands, have really honed this approach, but I'm not really sure if there's an equivalent model in software-land.

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  • Why is Microsoft under-supporting or under-developping VBNET?

    - by Will Marcouiller
    I ran into a situation where the lack of some features has become somewhat frustrating while developping in VB.NET 2.0. Since my first day of programming, I've always been a C programmer, and still am. Naturally, I chose C# as my favorite .NET language. Recently, a customer of mine has obliged that all of his development projects which disregard SharePoint development have to be written in VB.NET 2.0, that is to avoid conflictual systems to come into some problems. That is a legitimate choice of his which I approve somehow, since he's running some old central systems and is slowly migrating toward latest technologies. As for me, I would have prefered to go with C#, but then, never having done much VB in my life, I see it as an opportunity to learn somethings new, how to handle this and that in VBNET, etc. Except that the syntax is really too verbose for me, which is a pain! I got used to it and that is fine. However, I recently wanted to use the InternalsVisibleToAttribute which I discovered lastly here on SO. But then, in addition to not being able to have lambda expression that returns no value, which I discovered months ago, today I learn that I can't use the attribute in VBNET! Here is what I have read in an article: [...] Sorry VB.Net developers, Microsoft is again shunning you guys and this attribute is NOT available to you.... :( And here is the link: InternalsVisibleTo: Testing internal methods in .Net 2.0 I have heard from Anders Hejlsberg mouth while watching a Webcast from his presentation of .NET 4.0 Framework that the VBNET team was working or has worked in collaboration with the C# team (Eric Lippert and others) in order to bring VBNET to offer the same features as C# offers. But then, I say to myself that the VBNET team has a huge step forward to make, if already in .NET 2.0, some of the most important features lacked! So my question is this: Why is Microsoft under-supporting or under-developping VBNET? Will VBNET ever be lacking the C# features?

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  • Gravatar XML-RPC request problem in Objective-C

    - by Erik
    Hi all, I'm trying to incorporate some Gravatar functionality using its XML-RPC API in an iPhone app I'm writing. I grabbed the Cocoa XML-RPC Framework by Eric Czarny (http://github.com/eczarny/xmlrpc) and it works well when I tested it with some of the Wordpress methods. However, when I try to use the Gravatar API, I always receive a response of "Error code: -9 Authentication error". I think I'm constructing the request correctly, but I've been wracking my brain and can't seem to figure it out. Maybe someone has some experience with this API or can see what I'm doing wrong. Here's the call: <?xml version="1.0"> <methodCall> <methodName>grav.addresses</methodName> <params> <param><value><string>PASSWORD_HERE</string></value></param> </params> </methodCall> Again, the Cocoa XML-RPC Framework worked like a dream with Wordpress, but it's choking on the Gravatar API for some reason. Thanks for your help.

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  • Why is an Add method required for { } initialization?

    - by Dan Tao
    To use initialization syntax like this: var contacts = new ContactList { { "Dan", "[email protected]" }, { "Eric", "[email protected]" } }; ...my understanding is that my ContactList type would need to define an Add method that takes two string parameters: public void Add(string name, string email); What's a bit confusing to me about this is that the { } initializer syntax seems most useful when creating read-only or fixed-size collections. After all it is meant to mimic the initialization syntax for an array, right? (OK, so arrays are not read-only; but they are fixed size.) And naturally it can only be used when the collection's contents are known (at least the number of elements) at compile-time. So it would almost seem that the main requirement for using this collection initializer syntax (having an Add method and therefore a mutable collection) is at odds with the typical case in which it would be most useful. I'm sure I haven't put as much thought into this matter as the C# design team; it just seems that there could have been different rules for this syntax that would have meshed better with its typical usage scenarios. Am I way off base here? Is the desire to use the { } syntax to initialize fixed-size collections not as common as I think? What other factors might have influenced the formulation of the requirements for this syntax that I'm simply not thinking of?

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  • Generate number sequences with LINQ

    - by tanascius
    I try to write a LINQ statement which returns me all possible combinations of numbers (I need this for a test and I was inspired by this article of Eric Lippert). The method's prototype I call looks like: IEnumerable<Collection<int>> AllSequences( int start, int end, int size ); The rules are: all returned collections have a length of size number values within a collection have to increase every number between start and end should be used So calling the AllSequences( 1, 5, 3 ) should result in 10 collections, each of size 3: 1 2 3 1 2 4 1 2 5 1 3 4 1 3 5 1 4 5 2 3 4 2 3 5 2 4 5 3 4 5 Now, somehow I'd really like to see a pure LINQ solution. I am able to write a non LINQ solution on my own, so please put no effort into a solution without LINQ. My tries so far ended at a point where I have to join a number with the result of a recursive call of my method - something like: return from i in Enumerable.Range( start, end - size + 1 ) select BuildCollection(i, AllSequences( i, end, size -1)); But I can't manage it to implement BuildCollection() on a LINQ base - or even skip this method call. Can you help me here?

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  • Wordpress XML-RPC call from Objective C: wp.newComment

    - by radesix
    I'm using Eric Czarny's Cocoa XML-RPC framework to make a call to the Wordpress API's. I've downloaded the sample app from Wordpress which gives some good examples. Unfortunately the good examples are for every call EXCEPT wp.newComment. I'm trying to post a comment using the code below and I keep getting an error with a localized description that tells me to check my input parameters. I've checked and rechecked and I don't understand what is wrong. Any ideas? NSDictionary *commentStructure = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:0], @"comment_parent", @"xmlrpc anonymous comments plugin now enabled", @"content", @"Test Author", @"author", @"http://iphone.someurl.com", @"author_url", @"[email protected]", @"author_email", nil]; NSArray *args = [NSArray arrayWithObjects:[NSNumber numberWithInt:0], @"", @"", [NSNumber numberWithInt:[self.parentFeedItem.postID intValue]], commentStructure, nil]; // the param(s) NSString *server = [[[NSString alloc] initWithString:@"http://www.someurl.com/xmlrpc.php"] autorelease]; // the server NSString *method = [[[NSString alloc] initWithString:@"wp.newComment"] autorelease]; // the method XMLRPCRequest *request = [[XMLRPCRequest alloc] initWithHost:[NSURL URLWithString:server]]; [request setMethod:method withObjects:args]; id response = [self executeXMLRPCRequest:request]; [request release]; if( [response isKindOfClass:[NSError class]] ) { //return nil; NSLog(@"There was a problem"); NSLog([response localizedDescription]); }

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  • Making RDoc Ruby Gem Default on Mac OS X

    - by jkale
    Hey all, I've recently installed RDoc version (2.4.3) through Ruby gems to replace the one shipped with Mac OS X (version 1.0.1). Unfortunately, I can still only use RDoc 1.0.1 when I call run "rdoc" at the command line. rdoc -v returns: RDoc V1.0.1 - 20041108 I tried amending the $PATH variable to point the first entry to the RDoc 2.4.3 folder but no luck. I couldn't find anything about this online either, so I thought I'd ask here. Cheers! Update: Running "gem list -d --version 1.0.1 rdoc" returns: *** LOCAL GEMS *** rdoc (2.4.3) Authors: Eric Hodel, Dave Thomas, Phil Hagelberg, Tony Strauss Rubyforge: http://rubyforge.org/projects/rdoc Homepage: http://rdoc.rubyforge.org Installed at: /usr/local/lib/ruby/gems/1.8 RDoc is an application that produces documentation for one or more Ruby source files Therefore, it's definitely the Mac OSX version of RDoc that's interfering with the Gems version. Update 2: I found out, using: `bash --debugger rdoc` that the old version of RDoc was in /opt/local/bin. I deleted it and added my gems directory to my $PATH `export PATH=/usr/local/lib/ruby/gems/1.8/gems/` I now have a fresh working copy of the latest RDoc!

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  • Ext JS 4: Show all columns in Ext.grid.Panel as custom option

    - by MacGyver
    Is there a function that can be called on an Ext.grid.Panel in ExtJS that will make all columns visible, if some of them are hidden by default? Whenever an end-user needs to show the hidden columns, they need to click each column. Below, I have some code to add a custom menu option when you select a field header. I'd like to execute this function so all columns show. As an example below, I have 'Project ID' and 'User Created' hidden by default. By choosing 'Select All Columns' would turn those columns on, so they show in the list view. listeners: { ... }, afterrender: function() { var menu = this.headerCt.getMenu(); menu.add([{ text: 'Select All Columns', handler: function() { var columnDataIndex = menu.activeHeader.dataIndex; alert('custom item for column "'+columnDataIndex+'" was pressed'); } }]); } } }); =========================== Answer (with code): Here's what I decided to do based on Eric's code below, since hiding all columns was silly. afterrender: function () { var menu = this.headerCt.getMenu(); menu.add([{ text: 'Show All Columns', handler: function () { var columnDataIndex = menu.activeHeader.dataIndex; Ext.each(grid.headerCt.getGridColumns(), function (column) { column.show(); }); } }]); menu.add([{ text: 'Hide All Columns Except This', handler: function () { var columnDataIndex = menu.activeHeader.dataIndex; alert(columnDataIndex); Ext.each(grid.headerCt.getGridColumns(), function (column) { if (column.dataIndex != columnDataIndex) { column.hide(); } }); } }]); }

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  • Dynamically changing background color of a UIView

    - by EricM
    Hello- Here's my setup. I have a viewcontroller that I'm creating and adding as a subview. The viewcontroller presents some options that a user can chose from. The viewcontroller is being pushed in response to a "long press" gesture. Within the viewcontroller, I added a child UIView to group some other controls together so I can move them around the screen as a unit and, when they are displayed, center them on the location of the long press. Here is the code that instantiates the view controller, changes its location, and adds it as a subview: UserOptions *opts = [[UserOptions alloc] initWithNibName:@"UserOptions" bundle:nil]; [opts recenterOptions:location]; [self.view addSubview:opts.view]; That bit of code does create and push the viewcontroller, but the call to recenterOptions doesn't do anything. Here is that method: - (void) recenterOptions:(CGPoint)location { CGRect oldFrame = self.optionsView.frame; CGFloat newX = location.x; // + oldFrame.size.width / 2.0; CGFloat newY = location.y; // + oldFrame.size.height / 2.0; CGRect newFrame = CGRectMake(newX, newY, oldFrame.size.width, oldFrame.size.height); self.optionsView.frame = newFrame; } Note that self.optionsView is the child UIView that I added to the viewcontroller's nib. Does anyone know why I'm unable to change the location of the UIView? Regards, Eric

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  • What makes good web form styling for business applications?

    - by ProfK
    Styling forms (form elements) is something that even Eric Meyer prefers to avoid. However, most business forms, and that is where styling is at issue; 'contact us' forms are easy to style, put window estate at a premium, with more 'document level' (e.g. invoice) fields, plus 'detail level' (e.g. invoice line) fields. Factors I often find at play are: At my minimum, at least two horizontally adjacent fieldsets are required. In applications vs. public web pages, fixed positioning vs fluid layout is often better. Quantity of content is important, vs. exaggerated readability. Users know the system, and cues etc. take a back seat. In light of factors like these, is there any available guidence for styling web form based applications? Are there any CSS or JavaScript frameworks that would make my quest to style these applications better than Visual Studios still pathetic 'Auto-format' (what drugs were those people on? I will never take them.)

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  • Sampling Duplicates

    - by user3640982
    I have a dataset from which I need to sample. It is set up with an ID field and a year field. I want every record from the most current year and then I want the most current ID's but sampled from every 3rd year going back. The data is ordered by year. For example ID<-rep(1:3, 5) Year<-rep(c(1,2,3,4,5),each=3) df<-data.frame(ID,Year) ID Year 1 1 1 2 2 1 3 3 1 4 1 2 5 2 2 6 3 2 7 1 3 8 2 3 9 3 3 10 1 4 11 2 4 12 3 4 13 1 5 14 2 5 15 3 5 So from this example, I would want to return ID Year 1 1 1 2 2 1 3 3 1 4 1 4 5 2 4 6 3 4 I'm thinking that some combination of duplicated() and which() should get what I want, but the problem is duplicated() just tells if it has been repeated; it doesn't say which record is being repeated. which(duplicated(df$ID)) [1] 4 5 6 7 8 9 10 11 12 13 14 15 This a problem since not every ID exists in every year. Any help would be appreciated. Thanks, Eric

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  • How is a referencing environment generally implemented for closures?

    - by Alexandr Kurilin
    Let's say I have a statically/lexically scoped language with deep binding and I create a closure. The closure will consist of the statements I want executed plus the so called referencing environment, or, to quote this post, the collection of variables which can be used. What does this referencing environment actually look like implementation-wise? I was recently reading about ObjectiveC's implementation of blocks, and the author suggests that behind the scenes you get a copy of all of the variables on the stack and also of all the references to heap objects. The explanation claims that you get a "snapshot" of the referencing environment at the point in time of the closure's creation. Is that more or less what happens, or did I misread that? Is anything done to "freeze" a separate copy of the heap objects, or is it safe to assume that if they get modified between closure creation and the closure executing, the closure will no longer be operating on the original version of the object? If indeed there's copying being made, are there memory usage considerations in situations where one might want to create plenty of closures and store them somewhere? I think that misunderstanding of some of these concepts might lead to tricky issues like the ones Eric Lippert mentions in this blog post. It's interesting because you'd think that it wouldn't make sense to keep a reference to a value type that might be gone by the time the closure is called, but I'm guessing that in C# the compiler will figure out that the variable is needed later and put it into the heap instead. It seems that in most memory-managed languages everything is a reference and thus ObjectiveC is a somewhat unique situation with having to deal with copying what's on the stack.

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  • barebones sort algorithm

    - by user309322
    i have been asked to make a simple sort aglorithm to sort a random series of 6 numbers into numerical order. However i have been asked to do this using "Barebones" a theoretical language put forward in the Book Computer Science an overview. Some information on the language can be found here http://www.brouhaha.com/~eric/software/barebones/ Just to clarify i am a student teacher and have been doing anaysis on "mini-programing languages" and their uses in a teaching environment, i suggested to my tutor that i look at barebones and asked what sort of exmaple program i should write . He suggested a simple sort algorithm. Now since looking at the language i cant understand how i can do this without using arrays and if statements. The code to swap the value of variables would be while a not 0 do; incr Aux1; decr a; end; while b not 0 do; incr Aux2 decr b end; while Aux1 not 0 do; incr a; decr Aux1; end; while Aux2 not 0 do; incr b; decr Aux2; end; however the language does not provide < or operators

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  • How should rules for Aggregate Roots be enforced?

    - by MylesRip
    While searching the web, I came across a list of rules from Eric Evans' book that should be enforced for aggregates: The root Entity has global identity and is ultimately responsible for checking invariants Root Entities have global identity. Entities inside the boundary have local identity, unique only within the Aggregate. Nothing outside the Aggregate boundary can hold a reference to anything inside, except to the root Entity. The root Entity can hand references to the internal Entities to other objects, but they can only use them transiently (within a single method or block). Only Aggregate Roots can be obtained directly with database queries. Everything else must be done through traversal. Objects within the Aggregate can hold references to other Aggregate roots. A delete operation must remove everything within the Aggregate boundary all at once When a change to any object within the Aggregate boundary is committed, all invariants of the whole Aggregate must be satisfied. This all seems fine in theory, but I don't see how these rules would be enforced in the real world. Take rule 3 for example. Once the root entity has given an exteral object a reference to an internal entity, what's to keep that external object from holding on to the reference beyond the single method or block? (If the enforcement of this is platform-specific, I would be interested in knowing how this would be enforced within a C#/.NET/NHibernate environment.)

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  • Learning Java, how to type text on canvas?

    - by Voley
    I'm reading a book by Eric Roberts - Art and science of java and it got an excersise that I can't figure out - You have to make calendar, with GRect's, 7 by 6, that goes ok, the code part is easy, but also you have to type the numbers of the date on those rectangles, and it's kinda hard for me, there is nothing about it in the book. I tried using GLabel thing, but here arises the problem that I need to work on those numbers, and it says "can't convert from int to string and vice versa". GLabel (string, posX, posY) - it is not accepting int as a parameter, only string, I even tried typecasting, still not working. For example I want to make a loop int currentDate = 1; while (currentDate < 31) { add(new Glabel(currentDate, 100, 100); currentDate++; This code is saying that no man, can't convert int to string. If i try changing currentDate to string, it works, but I got a problem with calculation, as I can't manipulate with number in string, it doesn't even allow to typecast it into int. How can I fix it? Maybe there is another class or method to type the text over those rectangles? I know about println but it doen't have any x or y coordinates, so I can't work with it. And I think it's only for console programs.

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  • Communication between lexer and parser

    - by FredOverflow
    Every time I write a simple lexer and parser, I stumble upon the same question: how should the lexer and the parser communicate? I see four different approaches: The lexer eagerly converts the entire input string into a vector of tokens. Once this is done, the vector is fed to the parser which converts it into a tree. This is by far the simplest solution to implement, but since all tokens are stored in memory, it wastes a lot of space. Each time the lexer finds a token, it invokes a function on the parser, passing the current token. In my experience, this only works if the parser can naturally be implemented as a state machine like LALR parsers. By contrast, I don't think it would work at all for recursive descent parsers. Each time the parser needs a token, it asks the lexer for the next one. This is very easy to implement in C# due to the yield keyword, but quite hard in C++ which doesn't have it. The lexer and parser communicate through an asynchronous queue. This is commonly known under the title "producer/consumer", and it should simplify the communication between the lexer and the parser a lot. Does it also outperform the other solutions on multicores? Or is lexing too trivial? Is my analysis sound? Are there other approaches I haven't thought of? What is used in real-world compilers? It would be really cool if compiler writers like Eric Lippert could shed some light on this issue.

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  • When is a try catch not a try catch?

    - by Dearmash
    I have a fun issue where during application shutdown, try / catch blocks are being seemingly ignored in the stack. I don't have a working test project (yet due to deadline, otherwise I'd totally try to repro this), but consider the following code snippet. public static string RunAndPossiblyThrow(int index, bool doThrow) { try { return Run(index); } catch(ApplicationException e) { if(doThrow) throw; } return ""; } public static string Run(int index) { if(_store.Contains(index)) return _store[index]; throw new ApplicationException("index not found"); } public static string RunAndIgnoreThrow(int index) { try { return Run(index); } catch(ApplicationException e) { } return ""; } During runtime this pattern works famously. We get legacy support for code that relies on exceptions for program control (bad) and we get to move forward and slowly remove exceptions used for program control. However, when shutting down our UI, we see an exception thrown from "Run" even though "doThrow" is false for ALL current uses of "RunAndPossiblyThrow". I've even gone so far as to verify this by modifying code to look like "RunAndIgnoreThrow" and I'll still get a crash post UI shutdown. Mr. Eric Lippert, I read your blog daily, I'd sure love to hear it's some known bug and I'm not going crazy. EDIT This is multi-threaded, and I've verified all objects are not modified while being accessed

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  • Prototyping Qt/C++ in Python

    - by tstenner
    I want to write a C++ application with Qt, but build a prototype first using Python and then gradually replace the Python code with C++. Is this the right approach, and what tools (bindings, binding generators, IDE) should I use? Ideally, everything should be available in the Ubuntu repositories so I wouldn't have to worry about incompatible or old versions and have everything set up with a simple aptitude install. Is there any comprehensive documentation about this process or do I have to learn every single component, and if yes, which ones? Right now I have multiple choices to make: Qt Creator, because of the nice auto completion and Qt integration. Eclipse, as it offers support for both C++ and Python. Eric (haven't used it yet) Vim PySide as it's working with CMake and Boost.Python, so theoretically it will make replacing python code easier. PyQt as it's more widely used (more support) and is available as a Debian package. Edit: As I will have to deploy the program to various computers, the C++-solution would require 1-5 files (the program and some library files if I'm linking it statically), using Python I'd have to build PyQt/PySide/SIP/whatever on every platform and explain how to install Python and everything else.

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  • are margin and padding most disbalanced thing among all browser?

    - by metal-gear-solid
    While some people use this reset. * { margin: 0; padding: 0; } Is every element has default margin and padding in each browser default stylesheet( but differently)? While eric meyer collected some most used selectors and given this to all { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; } Are those elements has different type of font sizes? different baseline, different background, outline and border? if we keep besides cons of universal selector. is this * { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; } better than this * { margin: 0; padding: 0; }

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  • Trying to Insert Text to Access Database with ExecuteNonQueryin VB

    - by user3673701
    I'm working on this feature were i save text from a textbox on my form to a access database file. With the click on my "store" button I want to save the text in the corresponding textbox fields to the fields in my access database for searching and retrieving purposes. Im doing this in VB The problem I run into is the INSERT TO error with my "store" button Any help or insight as to why im getting error would be greatly appreciated. here is my code: Dim con As System.Data.OleDb.OleDbConnection Dim cmd As System.Data.OleDb.OleDbCommand Dim dr As System.Data.OleDb.OleDbDataReader Dim sqlStr As String Private Sub btnStore_Click(sender As Object, e As EventArgs) Handles btnStore.Click con = New System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Eric\Documents\SPC1.2.accdb") con.Open() MsgBox("Initialized") sqlStr = "INSERT INTO Master FADV Calll info (First Name, Last Name, Phone Number, Email, User Id) values (" & txtFirstName.Text & " ' ,'" & txtLastName.Text & "','" & txtPhone.Text & "', '" & txtEmail.Text & "', '" & txtUserID.Text & "', '" & txtOtherOptionTxt.Text & "','" & txtCallDetail.Text & "');" cmd = New OleDb.OleDbCommand(sqlStr, con) cmd.ExecuteNonQuery() <------- **IM RECIVING THE ERROR HERE** MsgBox("Stored") ''pass ther parameter as sq; query, con " connection Obj)" con.Close()'

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  • How can a B-tree node be represented?

    - by chronodekar
    We're learning B-trees in class and have been asked to implement them in code. The teacher has left choice of programming language to us and I want to try and do it in C#. My problem is that the following structure is illegal in C#, unsafe struct BtreeNode { int key_num; // The number of keys in a node int[] key; // Array of keys bool leaf; // Is it a leaf node or not? BtreeNode*[] c; // Pointers to next nodes } Specifically, one is not allowed to create a pointer to point to the structure itself. Is there some work-around or alternate approach I could use? I'm fairly certain that there MUST be a way to do this within the managed code, but I can't figure it out. EDIT: Eric's answer pointed me in the right direction. Here's what I ended up using, class BtreeNode { public List<BtreeNode> children; // The child nodes public static int MinDeg; // The Minimum Degree of the tree public bool IsLeaf { get; set; } // Is the current node a leaf or not? public List<int> key; // The list of keys ... }

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  • How do I pause main() until all other threads have died?

    - by thechiman
    In my program, I am creating several threads in the main() method. The last line in the main method is a call to System.out.println(), which I don't want to call until all the threads have died. I have tried calling Thread.join() on each thread however that blocks each thread so that they execute sequentially instead of in parallel. Is there a way to block the main() thread until all other threads have finished executing? Here is the relevant part of my code: public static void main(String[] args) { //some other initialization code //Make array of Thread objects Thread[] racecars = new Thread[numberOfRaceCars]; //Fill array with RaceCar objects for(int i=0; i<numberOfRaceCars; i++) { racecars[i] = new RaceCar(laps, args[i]); } //Call start() on each Thread for(int i=0; i<numberOfRaceCars; i++) { racecars[i].start(); try { racecars[i].join(); //This is where I tried to using join() //It just blocks all other threads until the current //thread finishes. } catch(InterruptedException e) { e.printStackTrace(); } } //This is the line I want to execute after all other Threads have finished System.out.println("It's Over!"); } Thanks for the help guys! Eric

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