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  • Parallel Processing Simulation in Javascript

    - by le_havre
    Hello, I'm new to JavaScript so forgive me for being a n00b. When there's intensive calculation required, it more than likely involves loops that are recursive or otherwise. Sometimes this may mean having am recursive loop that runs four functions and maybe each of those functions walks the entire DOM tree, read positions and do some math for collision detection or whatever. While the first function is walking the DOM tree, the next one will have to wait its for the first one to finish, and so forth. Instead of doing this, why not launch those loops-within-loops separately, outside the programs, and act on their calculations in another loop that runs slower because it isn't doing those calculations itself? Retarded or clever? Thanks in advance!

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  • c# Generic overloaded method dispatching ambiguous

    - by sebgod
    Hello, I just hit a situation where a method dispatch was ambiguous and wondered if anyone could explain on what basis the compiler (.NET 4.0.30319) chooses what overload to call interface IfaceA { } interface IfaceB<T> { void Add(IfaceA a); T Add(T t); } class ConcreteA : IfaceA { } class abstract BaseClassB<T> : IfaceB<T> { public virtual T Add(T t) { ... } public virtual void Add(IfaceA a) { ... } } class ConcreteB : BaseClassB<IfaceA> { // does not override one of the relevant methods } void code() { var concreteB = new ConcreteB(); // it will call void Add(IfaceA a) concreteB.Add(new ConcreteA()); } In any case, why does the compiler not warn me or even why does it compile? Thank you very much for any answers.

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  • Using .dll methods to load data from file in C# code

    - by Espinas.iss
    I want to use in C# these methods: * int LibRaw::open_datastream(LibRaw_abstract_datastream *stream) * int LibRaw::open_file(const char *rawfile) * int LibRaw::open_buffer(void *buffer, size_t bufsize) * int LibRaw::unpack(void) * int LibRaw::unpack_thumb(void) that are stored in a libraw.dll. These functions one by one load data from file... I've been reading about P/Invoke but i'm not sure how to invoke them. Can anyone show me an example how to use all of these functions together in C# to load file (raw image stored in folder) or just how to PIvoke one of them. Thanx!

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  • How to accomplish covariant return types when returning a shared_ptr?

    - by Kyle
    using namespace boost; class A {}; class B : public A {}; class X { virtual shared_ptr<A> foo(); }; class Y : public X { virtual shared_ptr<B> foo(); }; The return types aren't covariant (nor are they, therefore, legal), but they would be if I was using raw pointers instead. What's the commonly accepted idiom to work around this, if there is one?

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  • Replacing objects, handling clones, dealing with write logs

    - by Alix
    Hi everyone, I'm dealing with a problem I can't figure out how to solve, and I'd love to hear some suggestions. [NOTE: I realise I'm asking several questions; however, answers need to take into account all of the issues, so I cannot split this into several questions] Here's the deal: I'm implementing a system that underlies user applications and that protect shared objects from concurrent accesses. The application programmer (whose application will run on top of my system) defines such shared objects like this: public class MyAtomicObject { // These are just examples of fields you may want to have in your class. public virtual int x { get; set; } public virtual List<int> list { get; set; } public virtual MyClassA objA { get; set; } public virtual MyClassB objB { get; set; } } As you can see they declare the fields of their class as auto-generated properties (auto-generated means they don't need to implement get and set). This is so that I can go in and extend their class and implement each get and set myself in order to handle possible concurrent accesses, etc. This is all well and good, but now it starts to get ugly: the application threads run transactions, like this: The thread signals it's starting a transaction. This means we now need to monitor its accesses to the fields of the atomic objects. The thread runs its code, possibly accessing fields for reading or writing. If there are accesses for writing, we'll hide them from the other transactions (other threads), and only make them visible in step 3. This is because the transaction may fail and have to roll back (undo) its updates, and in that case we don't want other threads to see its "dirty" data. The thread signals it wants to commit the transaction. If the commit is successful, the updates it made will now become visible to everyone else. Otherwise, the transaction will abort, the updates will remain invisible, and no one will ever know the transaction was there. So basically the concept of transaction is a series of accesses that appear to have happened atomically, that is, all at the same time, in the same instant, which would be the moment of successful commit. (This is as opposed to its updates becoming visible as it makes them) In order to hide the write accesses in step 2, I clone the accessed field (let's say it's the field list) and put it in the transaction's write log. After that, any time the transaction accesses list, it will actually be accessing the clone in its write log, and not the global copy everyone else sees. Like this, any changes it makes will be done to the (invisible) clone, not to the global copy. If in step 3 the commit is successful, the transaction should replace the global copy with the updated list it has in its write log, and then the changes become visible for everyone else at once. It would be something like this: myAtomicObject.list = updatedCloneOfListInTheWriteLog; Problem #1: possible references to the list. Let's say someone puts a reference to the global list in a dictionary. When I do... myAtomicObject.list = updatedCloneOfListInTheWriteLog; ...I'm just replacing the reference in the field list, but not the real object (I'm not overwriting the data), so in the dictionary we'll still have a reference to the old version of the list. A possible solution would be to overwrite the data (in the case of a list, empty the global list and add all the elements of the clone). More generically, I would need to copy the fields of one list to the other. I can do this with reflection, but that's not very pretty. Is there any other way to do it? Problem #2: even if problem #1 is solved, I still have a similar problem with the clone: the application programmer doesn't know I'm giving him a clone and not the global copy. What if he puts the clone in a dictionary? Then at commit there will be some references to the global copy and some to the clone, when in truth they should all point to the same object. I thought about providing a wrapper object that contains both the cloned list and a pointer to the global copy, but the programmer doesn't know about this wrapper, so they're not going to use the pointer at all. The wrapper would be like this: public class Wrapper<T> : T { // This would be the pointer to the global copy. The local data is contained in whatever fields the wrapper inherits from T. private T thisPtr; } I do need this wrapper for comparisons: if I have a dictionary that has an entry with the global copy as key, if I look it up with the clone, like this: dictionary[updatedCloneOfListInTheWriteLog] I need it to return the entry, that is, to think that updatedCloneOfListInTheWriteLog and the global copy are the same thing. For this, I can just override Equals, GetHashCode, operator== and operator!=, no problem. However I still don't know how to solve the case in which the programmer unknowingly inserts a reference to the clone in a dictionary. Problem #3: the wrapper must extend the class of the object it wraps (if it's wrapping MyClassA, it must extend MyClassA) so that it's accepted wherever an object of that class (MyClass) would be accepted. However, that class (MyClassA) may be final. This is pretty horrible :$. Any suggestions? I don't need to use a wrapper, anything you can think of is fine. What I cannot change is the write log (I need to have a write log) and the fact that the programmer doesn't know about the clone. I hope I've made some sense. Feel free to ask for more info if something needs some clearing up. Thanks so much!

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  • What's the C strategy to "imitate" a C++ template ?

    - by Andrei Ciobanu
    After reading some examples on stackoverflow, and following some of the answers for my previous questions (1), I've eventually come with a "strategy" for this. I've come to this: 1) Have a declare section in the .h file. Here I will define the data-structure, and the accesing interface. Eg.: /** * LIST DECLARATION. (DOUBLE LINKED LIST) */ #define NM_TEMPLATE_DECLARE_LIST(type) \ typedef struct nm_list_elem_##type##_s { \ type data; \ struct nm_list_elem_##type##_s *next; \ struct nm_list_elem_##type##_s *prev; \ } nm_list_elem_##type ; \ typedef struct nm_list_##type##_s { \ unsigned int size; \ nm_list_elem_##type *head; \ nm_list_elem_##type *tail; \ int (*cmp)(const type e1, const type e2); \ } nm_list_##type ; \ \ nm_list_##type *nm_list_new_##type##_(int (*cmp)(const type e1, \ const type e2)); \ \ (...other functions ...) 2) Wrap the functions in the interface inside MACROS: /** * LIST INTERFACE */ #define nm_list(type) \ nm_list_##type #define nm_list_elem(type) \ nm_list_elem_##type #define nm_list_new(type,cmp) \ nm_list_new_##type##_(cmp) #define nm_list_delete(type, list, dst) \ nm_list_delete_##type##_(list, dst) #define nm_list_ins_next(type,list, elem, data) \ nm_list_ins_next_##type##_(list, elem, data) (...others...) 3) Implement the functions: /** * LIST FUNCTION DEFINITIONS */ #define NM_TEMPLATE_DEFINE_LIST(type) \ nm_list_##type *nm_list_new_##type##_(int (*cmp)(const type e1, \ const type e2)) \ {\ nm_list_##type *list = NULL; \ list = nm_alloc(sizeof(*list)); \ list->size = 0; \ list->head = NULL; \ list->tail = NULL; \ list->cmp = cmp; \ }\ void nm_list_delete_##type##_(nm_list_##type *list, \ void (*destructor)(nm_list_elem_##type elem)) \ { \ type data; \ while(nm_list_size(list)){ \ data = nm_list_rem_##type(list, tail); \ if(destructor){ \ destructor(data); \ } \ } \ nm_free(list); \ } \ (...others...) In order to use those constructs, I have to create two files (let's call them templates.c and templates.h) . In templates.h I will have to NM_TEMPLATE_DECLARE_LIST(int), NM_TEMPLATE_DECLARE_LIST(double) , while in templates.c I will need to NM_TEMPLATE_DEFINE_LIST(int) , NM_TEMPLATE_DEFINE_LIST(double) , in order to have the code behind a list of ints, doubles and so on, generated. By following this strategy I will have to keep all my "template" declarations in two files, and in the same time, I will need to include templates.h whenever I need the data structures. It's a very "centralized" solution. Do you know other strategy in order to "imitate" (at some point) templates in C++ ? Do you know a way to improve this strategy, in order to keep things in more decentralized manner, so that I won't need the two files: templates.c and templates.h ?

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  • NGINX/PHP downloading instead of executing

    - by Travis D
    I have an NGINX server with fastcgi/PHP running on it. I need to add userdirs to it, but I can't get PHP to execute the files - it just asks me if I want to download it. It does work without the userdir (eg: it works on physibots.info/hugs.php, but not physibots.info/~kisses/hugs.php) Any help is greatly appreciated. Config: server { listen 80; server_name physibots.info; access_log /home/virtual/physibots.info/logs/access.log; root /home/virtual/physibots.info/public_html; location ~ ^/~(.+?)(/.*)?\.php$ { fastcgi_param SCRIPT_FILENAME /home/$1/public_html$fastcgi_script_name; fastcgi_pass unix:/tmp/php.socket; } location ~ ^/~(.+?)(/.*)?$ { alias /home/$1/public_html$2; autoindex on; } location ~ \.php$ { try_files $uri /error.html/$uri?null; fastcgi_pass unix:/tmp/php.socket; } }

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  • How to create a new IDA project based on an existing one with different offsets?

    - by tbergelt
    I have an existing IDA Pro project for a C166 processor embedded application. This project already has many functions, variables, etc defined. There are different versions of the embedded application I am looking at. The different versions of the application are 99% the same, but with slight variations in code and data that cause functions and variables to be at different memory offsets. I want to create a new IDA project for a different version of the application. I would like to somehow import all of my function and variable definitions from my existing IDA project. I would like IDA to recognize the signatures of the existing function definitions and define them at there new location in the new project. How can I do this? Are there certain plugins for IDA I can chain together?

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  • Simplifying const Overloading?

    - by templatetypedef
    Hello all- I've been teaching a C++ programming class for many years now and one of the trickiest things to explain to students is const overloading. I commonly use the example of a vector-like class and its operator[] function: template <typename T> class Vector { public: T& operator[] (size_t index); const T& operator[] (size_t index) const; }; I have little to no trouble explaining why it is that two versions of the operator[] function are needed, but in trying to explain how to unify the two implementations together I often find myself wasting a lot of time with language arcana. The problem is that the only good, reliable way that I know how to implement one of these functions in terms of the other is with the const_cast/static_cast trick: template <typename T> const T& Vector<T>::operator[] (size_t index) const { /* ... your implementation here ... */ } template <typename T> T& Vector<T>::operator[] (size_t index) { return const_cast<T&>(static_cast<const Vector&>(*this)[index]); } The problem with this setup is that it's extremely tricky to explain and not at all intuitively obvious. When you explain it as "cast to const, then call the const version, then strip off constness" it's a little easier to understand, but the actual syntax is frightening,. Explaining what const_cast is, why it's appropriate here, and why it's almost universally inappropriate elsewhere usually takes me five to ten minutes of lecture time, and making sense of this whole expression often requires more effort than the difference between const T* and T* const. I feel that students need to know about const-overloading and how to do it without needlessly duplicating the code in the two functions, but this trick seems a bit excessive in an introductory C++ programming course. My question is this - is there a simpler way to implement const-overloaded functions in terms of one another? Or is there a simpler way of explaining this existing trick to students? Thanks so much!

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  • AS3: Removing EventListeners without knowing amount or names

    - by DevEight
    Hello! First shortly about how my site works: When a link is clicked it checks if something is already displayed in either the Left or Right side of the screen (the website looks like a book, so I have a left page I want to display information on and a right page). If there is already something showing it hides it and displays the new object, together with this it enables all the buttons within that object (I have separate functions to set up each object). An example of such an EventListener would be: pathTo.Button1.addEventListener(MouseEvent.CLICK, function():void {showText(side, object)}); What I'm trying to do is to remove all the previous set EventListeners without having to create separate functions for removing the links inside every object as well. Shorter version: How do I remove all EventListeners on all objects inside another object? The only variable I want to store is the object containing everything. There are however not always EventListeners within the objects.

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  • C++ inheritance and member function pointers

    - by smh
    In C++, can member function pointers be used to point to derived (or even base) class members? EDIT: Perhaps an example will help. Suppose we have a hierarchy of three classes X, Y, Z in order of inheritance. Y therefore has a base class X and a derived class Z. Now we can define a member function pointer p for class Y. This is written as: void (Y::*p)(); (For simplicity, I'll assume we're only interested in functions with the signature void f() ) This pointer p can now be used to point to member functions of class Y. This question (two questions, really) is then: Can p be used to point to a function in the derived class Z? Can p be used to point to a function in the base class X?

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  • Identifying a function call in a python script line in runtime

    - by Dani
    I have a python script that I run with 'exec'. The script's string has calls to functions. When a function is called, I would like it to know the line number and offset in line for that call in the script (in the string I fed exec with). Here is an example. If my script is: foo1(); foo2(); foo1() foo3() And if I have code that prints (line,offset) in every function, I should get (0,0), (0,8), (0,16), (1,0) In most cases this can be easily done by getting the stack frame, because it contains the line number and the function name. The only problem is when there are two functions with the same name in a certain line. Unfortunately this is a common case for me. Any ideas?

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  • VirtualHost problem with passenger (mod_rails)

    - by Jake
    Hi all, I'm at my wit's end here with virtual hosting. I'm trying to install redmine and it works with the webrick test server, but when I tried to use passenger (mod_rails) to host and go to the address I specified when in the virtualhost part of my apache config file nothing happens. Here is the relavent section of /etc/httpd/conf/httpd.conf where I try to set up the virtual host: <VirtualHost *:80> SetEnv RAILS_ENV production ServerName redmine.MYSITE.com:80 DocumentRoot /opt/redmine-1.0.5/public/ <Directory /opt/redmine-1.0.5/public/> Options -MultiViews Allow from all AllowOverride none </Directory> However, when I got to redmine.MYSITE.com:80 nothing happens, I just get our normal home page. I have no idea what the problem is, any help our guidance would be greatly appreciated. If you need any other information, please tell me and I'll provide it.

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  • Function Composition in C++

    - by Channel72
    There are a lot of impressive Boost libraries such as Boost.Lambda or Boost.Phoenix which go a long way towards making C++ into a truly functional language. But is there a straightforward way to create a composite function from any 2 or more arbitrary functions or functors? If I have: int f(int x) and int g(int x), I want to do something like f . g which would statically generate a new function object equivalent to f(g(x)). This seems to be possible through various techniques, such as those discussed here. Certainly, you can chain calls to boost::lambda::bind to create a composite functor. But is there anything in Boost which easily allows you to take any 2 or more functions or function objects and combine them to create a single composite functor, similar to how you would do it in a language like Haskell?

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  • Opinions regarding C++ programming practice

    - by Sagar
    I have a program that I am writing, not too big. Apart from the main function, it has about 15 other functions that called for various tasks at various times. The code works just fine all in one file, and as it is right now. However, I was wondering if anyone had any advice on whether it is smarter/more efficient/better programming to put those functions in a separate file different from where main is, or whether it even matters at all. If yes, why? If no, why not? I am not new at C++, but definitely not an expert either, so if you think this question is stupid, feel free to tell me so. Thanks for your time!

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  • Difference between Cloud and Virtualization

    - by Akash Kava
    Ops: This does not belong to ServerFault because it focuses on Programing Architecture. I have following questions regarding differences between Cloud and Virtualization.. How Cloud is different then Virtualization? Currently I tried to find out pricing of Rackspace, Amazone and all similar cloud providers, I found that our current 6 dedicated servers came cheaper then their pricing. So how one can claim cloud is cheaper? Is it cheaper only in comparison of normal hosting? We re organized our infrastructure in virtual environment to reduce or configuration overhead at time of failure, we did not have to rewrite any peice of code that is already written for earlier setup. So moving to virtualization does not require any re programming. But cloud is absoltely different and it will require entire reprogramming right? Is it really worth to recode when our current IT costs are 3-4 times lower then cloud hosting including raid backups and all sort of clustering for high availability? New programming architecture means new overheads of training staff, new methods of testing and new deployment schemes, does it justify over "on demand resource usage" words of cloud? We are having current development architecture with simple Server side ASP.NET WebServices with no local context and on client side Flex/Silverlight which offers pretty good REST architecture and its highly scalable. How does cloud differs from REST model of deployment? On storage, SQL Server or MySQL offers pretty good replication and high availibility then what is advantage in cloud? Data guarantee, one of our vendor hosting some other customer's app on cloud (one of most used), lost Entire Hard Disk (the virtual) and entire module in first 6 months. Second provider said its your duty to take backup, fine I agree, but no provider gives SLA for data guarantee, they give 99% uptime. However in most business apps, uptime is less important then data integrity. In our 10 years of dedicated hosting experience we had only one hard disk crash. This makes me little skeptical to go for cloud and loosing control over data. And I feel its just a big marketing buzz to sell virtulization in different form. Size of data, currently all providers charge very heavy for large data, if you are hosting only below 100GB cloud can be good alternative, but I think virtual servers and dedicated servers above 100GB to few TBs are still cheaper. Why would want to pay so high on cloud when there is no data guarentee as well as it doesnt say anything about redundancy. (I wish SO had something for spell check for Internet Explorer, sorry for wrong spellings in my post)

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  • IIS5, ASP.NET (3.5) Application and Visual Studio 2008

    - by Lakeshore
    I have a solution that was developed in VS 2008 that is configured to use IIS. I configure the Virtual directory in IIS the same way I have with other working solutions using IIS. When I either build and run the solution in VS 2008 or browse the virtual directory using IIS, I get the following error message. Internet Explorer cannot display the webpage What you can try: It appears you are not connected to the Internet, but you might want to try to reconnect to the Internet Retype the address Go back to the previous page. Most likely causes: You are not connected to the Internet The website is encountering problems There might be a typing error in the address. Why might this be?

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  • Why is sqrt() not a method on Float?

    - by KaptajnKold
    In Ruby everything is an object. That's why I don't understand why we have the Math module. It seems to me that most (all?) of the functions in the Math module should have been methods on the numeric types like Integer, Float and so on. E.g. instead of Math.sqrt(5) it would make more sense to have 5.sqrt The same goes for sin, cos, tan, log10 and so on. Does anyone know why all these functions ended up in the Math module?

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  • Adding the text area input to a list with jquery

    - by amylynn83
    I am making a shopping list app. When an item is added to the text input, it should be converted into a list item with a class of "tile" and added to the beginning of the list with a class of ".shopping_item_list". Here is my HTML: <section> <h1 class="outline">Shopping List Items</h1> <ul class="shopping_item_list"> <li class="tile">Flowers<span class="delete">Delete</span></li> </ul> </section> My jQuery: $("input[name='shopping_item']").change(function() { var item = $(this).val(); $("<li class='tile'>+ item +</li>").prependTo(".shopping_item_list"); $(".tile").removeClass("middle"); $(".shopping_item_list li:nth-child(3n+2)").addClass("middle"); }); This isn't working, and I can't figure out why. I'm new to jQuery. Also, I need to add the "delete" span to the list item and am not sure how. Thanks for any help you can offer! Edited to add: Thanks to the feedback here, I was able to make it work with: $("input[name='shopping_item']").change(function() { var item = $(this).val(); $("<li class='tile'>" + item + "<span class='delete'>Delete</span>" + " </li>").prependTo(".shopping_item_list"); $(".tile").removeClass("middle"); $(".shopping_item_list li:nth-child(3n+2)").addClass("middle"); }); However, in my jquery, I have functions for the classes "tile" and "delete" that are not working for newly added items. // hide delete button $(".delete").hide(); // delete square $(".tile").hover(function() { $(this).find(".delete").toggle(); }); $(".tile").on("click", ".delete", function() { $(this).closest("li.tile").remove(); $(".tile").removeClass("middle"); $(".shopping_item_list li:nth-child(3n+2)").addClass("middle"); }); // cross off list $(".tile").click(function() { $(this).toggleClass("deleteAction"); }); The new items, which have these classes applied aren't using these functions at all. Do I need to add the functions below the add item? Does the order in which they appear in my js file matter? Do I need to add some kind of function?

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  • Calling a function that has 'Activity' as an argument.

    - by Andrew
    I have stripped down my functions for simplicity: public static int countLines(String fileName, Activity activity) throws IOException { BufferedReader in = new BufferedReader(new InputStreamReader(activity.getAssets().open(fileName))); return 3; } I am calling it from here: private CharSequence RandomRead() throws IOException { int numberLines = countLines("data.txt", ??????); return "Success" } In the call to countLines("data.txt", ??????), what do I put as the argument for the Activity? I've Googled all night and I can find no examples of an actual call to a function where Activity is an argument. (Lots of examples actually using 'activity', but no calls to the example functions). Thanks!

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  • Django, javascript and code ruse problem

    - by dragoon
    Hi, I have some sort of a design problem with my Django AJAX application. I have a template where I initialize js variable from django context variable like so: var test = "{{ test }}"; This variable is than used in a number of js functions that are needed for interface to work properly. So now I'm trying to reuse some content from this page in another page that loads it dynamically on some user interaction using jQuery.load(..), and I don't see any way how I can initialize that variable, so js functions don't work now. Is there any solution for this or may be I'm doing it wrong? Thanks.

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  • Perl: How do I extract certain bits from a byte and then covert these bits to a hex value?

    - by Siegfried Hepp
    I need to extract certain bits of a byte and covert the extract bits back to a hex value. Example (the value of the byte is 0xD2) : 76543210 bit position 11010010 is 0xD2 Bit 0-3 defines the channel which is 0010b is 0x2 Bit 4-5 defines the controller which is 01b is 0x1 Bit 6-7 defines the port which is 11b is 0x3 I somehow need to get from the byte is 0xD2 to channel is 0x2, controller is 0x1, port is 0x3 I googled allot and found the functions pack/unpack, vec and sprintf. But I'm scratching by head how to use the functions to achieve this. Any idea how to achieve this in Perl ?

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  • code folding in Visual Studio for F#

    - by Yin Zhu
    I find that I tend to write long source files in F#. Some open source projects in F# also have long source files, e.g. FPersec and F# for excel. So it would be very helpful if code folding (even very limited support) is available in VS for F#. E.g. in a module, we can fold out functions that are stable, only leave functions that are subject to change unfold. Is this feature easy to be supported, e.g. by a third party vendor?

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  • NHibernate and objects with value-semantics

    - by Groo
    Problem: If I pass a class with value semantics (Equals method overridden) to NHibernate, NHibernate tries to save it to db even though it just saved an entity equal by value (but not by reference) to the database. What am I doing wrong? Here is a simplified example model for my problem: Let's say I have a Person entity and a City entity. One thread (producer) is creating new Person objects which belong to a specific existing City, and another thread (consumer) is saving them to a repository (using NHibernate as DAL). Since there is lot of objects being flushed at a time, I am using Guid.Comb id's to ensure that each insert is made using a single SQL command. City is an object with value-type semantics (equal by name only -- for this example purposes only): public class City : IEquatable<City> { public virtual Guid Id { get; private set; } public virtual string Name { get; set; } public virtual bool Equals(City other) { if (other == null) return false; return this.Name == other.Name; } public override bool Equals(object obj) { return Equals(obj as City); } public override int GetHashCode() { return this.Name.GetHashCode(); } } Fluent NH mapping is something like: public class PersonMap : ClassMap<Person> { public PersonMap() { Id(x => x.Id) .GeneratedBy.GuidComb(); References(x => x.City) .Cascade.SaveUpdate(); } } public class CityMap : ClassMap<City> { public CityMap() { Id(x => x.Id) .GeneratedBy.GuidComb(); Map(x => x.Name); } } Right now (with my current NHibernate mapping config), my consumer thread maintains a dictionary of cities and replaces their references in incoming person objects (otherwise NHibernate will see a new, non-cached City object and try to save it as well), and I need to do it for every produced Person object. Since I have implemented City class to behave like a value type, I hoped that NHibernate would compare Cities by value and not try to save them each time -- i.e. I would only need to do a lookup once per session and not care about them anymore. Is this possible, and if yes, what am I doing wrong here?

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  • MVC DropDownListFor not populating the selected value

    - by user2254436
    I'm really having troubles with MVC, in another project I've done the same thing and it worked fine but in this project I just don't understand why the selected item in the dropdown is not populating the class correctly with EF. I have 2 classes: public partial class License { public License() { this.Customers = new HashSet<Customer>(); } public int LicenseID { get; set; } public int Lic_LicenseTypeID { get; set; } public int Lic_LicenseStatusID { get; set; } public string Lic_LicenseComments { get; set; } public virtual EntitiesList LicenseStatus { get; set; } public virtual EntitiesList LicenseType { get; set; } } public partial class EntitiesList { public EntitiesList() { this.LicensesStatus = new HashSet<License>(); this.LicensesType = new HashSet<License>(); } public int ListID { get; set; } public string List_EntityValue { get; set; } public string List_Comments { get; set; } public string List_EntityName { get; set; } public virtual ICollection<License> LicensesStatus { get; set; } public virtual ICollection<License> LicensesType { get; set; } public string List_DisplayName { get { return Regex.Replace(List_EntityName, "([a-z])([A-Z])", "$1 $2"); ; } } public string List_DisplayValue { get { return Regex.Replace(List_EntityValue, "([a-z])([A-Z])", "$1 $2"); } } } The EntitiesList is table in db that have all my "enum" lists. For example: ListID - 0 List_EntityValue - Activate List_EntityName - LicenseStatus ListID - 1 List_EntityValue - Basic List_EntityName - LicenseType This is my model: public class LicenseModel { public License License { get; set; } public SelectList LicenseStatuses { get; set; } public int SelectedStatus { get; set; } public SelectList LicenseTypes { get; set; } public int SelectedType { get; set; } } My controller for create: public ActionResult Create() { LicenseModel model = new LicenseModel(); model.License = new License(); model.LicenseStatuses = new SelectList(managerLists.GetAllLicenseStatuses(), "ListID", "List_DisplayValue"); model.LicenseTypes = new SelectList(managerLists.GetAllLicenseTypes(), "ListID", "List_DisplayValue"); return View(model); } [HttpPost] [ValidateAntiForgeryToken] public ActionResult Create(LicenseModel model) { if (ModelState.IsValid) { model.License.Lic_LicenseTypeID = model.SelectedType; model.License.Lic_LicenseStatusID = model.SelectedStatus; managerLicense.AddNewObject(model.License); return RedirectToAction("Index"); } return View(model); } managerLists and managerLicense are the managers that connect between the entities in db and the MVC UI, nothing special... they contains queries for adding new objects, getting the lists, editing and so on. And the view for creating the License: @using (Html.BeginForm()) { @Html.AntiForgeryToken() @Html.ValidationSummary(true) <fieldset> <legend>License</legend> <div class="form-group"> @Html.LabelFor(model => model.License.Lic_LicenseTypeID) @Html.DropDownListFor(model => model.SelectedType, Model.LicenseTypes, new { @class = "form-control" }) <p class="help-block">@Html.ValidationMessageFor(model => model.License.Lic_LicenseTypeID)</p> </div> <div class="form-group"> @Html.LabelFor(model => model.License.Lic_LicenseStatusID) @Html.DropDownListFor(model => model.SelectedStatus, Model.LicenseStatuses, new { @class = "form-control" }) <p class="help-block">@Html.ValidationMessageFor(model => model.License.Lic_LicenseStatusID)</p> </div> <div class="form-group"> @Html.LabelFor(model => model.License.Lic_LicenseComments) @Html.TextAreaFor(model => model.License.Lic_LicenseComments, new { @class = "form-control", rows = "3" }) <p class="help-block">@Html.ValidationMessageFor(model => model.License.Lic_LicenseComments)</p> </div> <p> <input type="submit" value="Create" /> </p> </fieldset> } Now, when I'm trying to save the new license, when it gets to the db.SaveChanges() in the manager I'm getting: "Validation failed for one or more entities. See 'EntityValidationErrors' property for more details." In breakpoint, the Lic_LicenseTypeID and Lic_LicenseStatusID are getting correctly the ID's from the selected item in the dropdown but the LicenseStatus and LicenseStatus properties are null. What an I missing?

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