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  • Toggle two divs and classes

    - by kuswantin
    I have two links with classes (login-form and register-form) relevant to their target forms ID, they want to toggle. I have also a predefined 'slideToggle' function to toggle better. This is what I have tried so far: $('#userbar a').click(function() { var c = $(this).attr('class'); $('#userbar a').removeClass('active'); $(this).toggleClass('active'); $('#register-form,#login-form').hide(); //bad, causing flashy $('#' + c).slideToggle('slow'); return false; }); With this I have trouble with the flashy window, and to correctly toggle the active classes when another link is clicked, the other link should not have active class anymore. Additional problem is the link is dead on serial clicks. I have another try, longer one: $('#userbar a').click(function() { var c = $(this).attr('class'); switch (c) { case 'login-form': $('#' + c).slideToggle('slow'); $(this).toggleClass('active'); $('#register-form').hide(); break; case 'register-form': $('#' + c).slideToggle('slow'); $(this).toggleClass('active'); $('#login-form').hide(); break; } return false; }); This one is worse than the first :( Any suggestion to correct the behavior? What I want is when a link with class login-form is click, so toggle the form with ID login-form, and hide the register-form if open. Any help would be very much appreciated. Thanks.

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  • Cryptography: best practices for keys in memory?

    - by Johan
    Background: I got some data encrypted with AES (ie symmetric crypto) in a database. A server side application, running on a (assumed) secure and isolated Linux box, uses this data. It reads the encrypted data from the DB, and writes back encrypted data, only dealing with the unencrypted data in memory. So, in order to do this, the app is required to have the key stored in memory. The question is, is there any good best practices for this? Securing the key in memory. A few ideas: Keeping it in unswappable memory (for linux: setting SHM_LOCK with shmctl(2)?) Splitting the key over multiple memory locations. Encrypting the key. With what, and how to keep the...key key.. secure? Loading the key from file each time its required (slow and if the evildoer can read our memory, he can probably read our files too) Some scenarios on why the key might leak: evildoer getting hold of mem dump/core dump; bad bounds checking in code leading to information leakage; The first one seems like a good and pretty simple thing to do, but how about the rest? Other ideas? Any standard specifications/best practices? Thanks for any input!

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  • Generic InBetween Function.

    - by Luiscencio
    I am tired of writing x > min && x < max so i wawnt to write a simple function but I am not sure if I am doing it right... actually I am not cuz I get an error: bool inBetween<T>(T x, T min, T max) where T:IComparable { return (x > min && x < max); } errors: Operator '>' cannot be applied to operands of type 'T' and 'T' Operator '<' cannot be applied to operands of type 'T' and 'T' may I have a bad understanding of the where part in the function declaring note: for those who are going to tell me that I will be writing more code than before... think on readability =) any help will be appreciated EDIT deleted cuz it was resolved =) ANOTHER EDIT so after some headache I came out with this (ummm) thing following @Jay Idea of extreme readability: public static class test { public static comparision Between<T>(this T a,T b) where T : IComparable { var ttt = new comparision(); ttt.init(a); ttt.result = a.CompareTo(b) > 0; return ttt; } public static bool And<T>(this comparision state, T c) where T : IComparable { return state.a.CompareTo(c) < 0 && state.result; } public class comparision { public IComparable a; public bool result; public void init<T>(T ia) where T : IComparable { a = ia; } } } now you can compare anything with extreme readability =) what do you think.. I am no performance guru so any tweaks are welcome

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  • Newb Question: scanf() in C

    - by riemannliness
    So I started learning C today, and as an exercise i was told to write a program that asks the user for numbers until they type a 0, then adds the even ones and the odd ones together. Here is is (don't laugh at my bad style): #include <stdio.h>; int main() { int esum = 0, osum = 0; int n, mod; puts("Please enter some numbers, 0 to terminate:"); scanf("%d", &n); while (n != 0) { mod = n % 2; switch(mod) { case 0: esum += n; break; case 1: osum += n; } scanf("%d", &n); } printf("The sum of evens:%d,\t The sum of odds:%d", esum, osum); return 0; } My question concerns the mechanics of the scanf() function. It seems that when you enter several numbers at once separated by spaces (eg. 1 22 34 2 8), the scanf() function somehow remembers each distinct numbers in the line, and steps through the while loop for each one respectively. Why/how does this happen? Example interaction within command prompt: - Please enter some numbers, 0 to terminate: 42 8 77 23 11 (enter) 0 (enter) - The sum of evens:50, The sum of odds:111 I'm running the program through the command prompt, it's compiled for win32 platforms with visual studio.

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  • Easy way to lock a file on a remote machine (windows)?

    - by roufamatic
    I've tracked down an error in my logs, and am trying to reproduce it. My theory is that a file sometimes gets locked in a specific folder, and when the application (ASP.NET) tries to delete that folder it hangs. I don't have the application running on my own machine so I'm debugging this on a remote server. But for the life of me, I can't seem to figure out a way to lock a file that prevents it from being deleted by the process. My first thought was to map the network path to a local drive and just leave a command prompt open to that folder. Locally that always fouls up my folder deletes, but apparently SMB is a bit more robust and doesn't grant me a lock. After that I created an infinte loop vbscript in the folder and executed it remotely. The file was deleted out from underneath the executing code. Man! I then tried creating a file on the server in that folder and removing all permissions. That didn't do the trick. I don't have access to the IIS settings so perhaps it's running under a privileged system account. So: what's a program that you know is free and I can quickly use to create an exclusive lock on a file so I can test my delete theory? Like a really, really bad Notepad clone or something. :-)

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  • Twitter api - no more than 150 requests per hour....

    - by RenegadeAndy
    Hi. I am writing a twitter app using jtwitter - and its running inside a server inside my work. Anyway - whenever i run it from work it returns the error below and I am only making a couple requests per hour: HTTP/1.1 400 Bad Request {"request":"/1/statuses/user_timeline.json?count=6&id=cicsdemo&","error":"Rate limit exceeded. Clients may not make more than 150 requests per hour."} ] 2010-06-03 18:44:49 zero.timer.TimerTask::run Thread-3 SEVERE [ CWPZA3100E: Exception during processing for timer task, "twitterTimer". Exception: java.lang.ClassCastException: winterwell.jtwitter.Twitter$Status incompatible with java.lang.String ] I run the same code from home - its fine. So obviously at some point twitter thinks our work is all coming from one direct IP - which is why its hitting a limit which it shouldnt. Do I have any choice or workaround - can i make the limit be counted from my direct machine IP - or to my account instead of IP? Can i use a proxy? Has any body else had this problem and solved it?! Before anyone asks the APP must live inside my work - it cannot run anywhere else! Cheers, Andy

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  • What type of web service should I put together?

    - by Jake
    I want to write a web service using Visual Studio. The service needs to support some type of authentication, and should be able to receive commands via simple HTTP GET requests. The input would only be a method call with some parameters, and the responses will be simple status/error codes. My instinct would be to go with an ASP.NET Web Service, but this isn't an option in C# 4.0 and it makes me wonder if I should be using something that's more up-to-date. I've looked into WCF, but it seems like this requires a running application on the client-side - is there a way to query a WCF host by just accessing a URL? The authentication is also an important piece. Developing my own little authentication system seems like a bad idea - I've read that it's too easy to mess up. What would be the standard way of authenticating with a web service like this? I'd love to look up all of the specifics on this and learn it myself, but I really don't even know where to begin. Some direction would be greatly appreciated!

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  • keyUp event heard?: Overridden NSView method

    - by Old McStopher
    UPDATED: I'm now overriding the NSView keyUp method from a NSView subclass set to first responder like below, but am still not seeing evidence that it is being called. @implementation svsView - (BOOL)acceptsFirstResponder { return YES; } - (void)keyUp:(NSEvent *)event { //--do key up stuff-- NSLog(@"key up'd!"); } @end --ORIGINAL POST-- I'm new to Cocoa and Obj-C and am trying to do a (void)keyUp: from within the implementation of my controller class (which itself is of type NSController). I'm not sure if this is the right place to put it, though. I have a series of like buttons each set to a unique key equivalent (IB button attribute) and each calls my (IBAction)keyInput method which then passes the identity of each key onto another object. This runs just fine, but I also want to track when each key is released. --ORIGINAL [bad] EXAMPLE-- @implementation svsController //init //IBActions - (IBAction)keyInput:(id)sender { //--do key down stuff-- } - (void)keyUp:(NSEvent *)event { //--do key up stuff-- } @end Upon fail, I also tried the keyUp as an IBAction (instead of void), like the user-defined keyInput is, and hooked it up to the appropriate buttons in Interface Builder, but then keyUp was only called when the keys were down and not when released. (Which I kind of figured would happen.) Pardon my noobery, but should I be putting this method in another class or doing something differently? Wherever it is, though, I need it be able to access objects owned by the controller class. Thanks for any insight you may have.

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  • Macro to improve callback registration readability

    - by Warren Seine
    I'm trying to write a macro to make a specific usage of callbacks in C++ easier. All my callbacks are member functions and will take this as first argument and a second one whose type inherits from a common base class. The usual way to go is: register_callback(boost::bind(&my_class::member_function, this, _1)); I'd love to write: register_callback(HANDLER(member_function)); Note that it will always be used within the same class. Even if typeof is considered as a bad practice, it sounds like a pretty solution to the lack of __class__ macro to get the current class name. The following code works: typedef typeof(*this) CLASS; boost::bind(& CLASS :: member_function, this, _1)(my_argument); but I can't use this code in a macro which will be given as argument to register_callback. I've tried: #define HANDLER(FUN) \ boost::bind(& typeof(*this) :: member_function, this, _1); which doesn't work for reasons I don't understand. Quoting GCC documentation: A typeof-construct can be used anywhere a typedef name could be used. My compiler is GCC 4.4, and even if I'd prefer something standard, GCC-specific solutions are accepted.

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  • WCF service reference namespace differs from original

    - by Thorarin
    I'm having a problem regarding namespaces used by my service references. I have a number of WCF services, say with the namespace MyCompany.Services.MyProduct (the actual namespaces are longer). As part of the product, I'm also providing a sample C# .NET website. This web application uses the namespace MyCompany.MyProduct. During initial development, the service was added as a project reference to the website and uses directly. I used a factory pattern that returns an object instance that implements MyCompany.Services.MyProduct.IMyService. So far, so good. Now I want to change this to use an actual service reference. After adding the reference and typing MyCompany.Services.MyProduct in the namespace textbox, it generates classes in the namespace MyCompany.MyProduct.MyCompany.Services.MyProduct. BAD! I don't want to have to change using directives in several places just because I'm using a proxy class. So I tried prepending the namespace with global::, but that is not accepted. Note that I hadn't even deleted the original assembly references yet, and "reuse types" is enabled, but no reusing was done, apparently. However, I don't want to keep the assembly references around in my sample website for it to work anyway. The only solution I've come up with so far is setting the default namespace for my web application to MyCompany (because it cannot be empty), and adding the service reference as Services.MyProduct. Suppose that a customer wants to use my sample website as a starting point, and they change the default namespace to OtherCompany.Whatever, this will obviously break my workaround. Is there a good solution to this problem? To summarize: I want to generate a service reference proxy in the original namespace, without referencing the assembly. Note: I have seen this question, but there was no solution provided that is acceptable for my use case. Edit: As John Saunders suggested, I've submitted some feedback to Microsoft about this: Feedback item @ Microsoft Connect

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  • How can I design a custom control in Javascript (possibly using jQuery)

    - by Mathieu Pagé
    I'd like to create a custom control in javascript. The goal is to create a building block that has methods, properties and events and render into a div. An example of one such control would be a calendar. It would render into a div, it would have properties that would define how it's displayed and what date is selected or highlighted, it would have methods to change the current month or to select some date and it would raise events when a day is clicked or the current month is changed by a user input. I can think of lots of way to implement this and I'm not sure what is the best way. I seem to remember that it's a bad thing to augment a DOM elements with properties and method, so I ruled that out. A jQuery plugin seems like a good idea, however I'm not sure if it's appropriate to create a plugin for each and every method my control would have so I could then use it like : $('#control').method1(); $('#control').method2(); And if I do use jQuery, where do I store the private data of my control? Another idea I got was to create a new kind of object that would have a reference to a div in which it could render it's elements. So what is the prefered way to do this. If I can I would like to do this as a jQuery plugin, but I'd need guidlines on how to create methods and where to store private data. I've loked at Plugins/Authoring on jQuery website and it did not helped that much in this regard.

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  • How to learn a C++ GUI library effectively?

    - by Chan
    Hello everyone, I have many options for GUI in my head while searching in stackoverflow, but these are what I chose among others: Qt gtkmm GTK+ I used GTK+ couple years ago, and I felt so painful when using C API without string object and containers. I prefer C++ style, I then switched to C++ gtkmm, but the documentation was bad at that time. I found no help when encountering an issue. Now I want to give a hard try for Qt4, but I really want to know how to learn a GUI librarie effectively. With core C++, I usually pick up a problem and try to solve it in different ways using that particular technique, functionality. On the other hand, after skimming through the documentation from Qt site, I don't think this way of studying is applicable, since the GUI classes and APIs are so much bigger. Plus I'm still in school, so I won't have much time to play all the day long with it. How do you guys learn GUI before? Can anyone share some experiences how they learn thing, that would be an invaluable input for me! Best regards, Chan Nguyen

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  • ORA- 01157 / Cant connect to database

    - by Tom
    Hi everyone, this is a follow up from this question. Let me start by saying that i am NOT a DBA, so i'm really really lost with this. A few weeks ago, we lost contact with one of our SID'S. All the other services are working, but this one in particular is not. What we got was this message when trying to connect ORA-01033: ORACLE initialization or shutdown in progress An attempt to alter database open ended up in ORA-01157: cannot identify/lock data file 6 - see DBWR trace file ORA-01110: data file 6: '/u01/app/oracle/oradata/xxx/xxx_data.dbf' I tried to shutdown / restart the database, but got this message. Total System Global Area 566231040 bytes Fixed Size 1220604 bytes Variable Size 117440516 bytes Database Buffers 444596224 bytes Redo Buffers 2973696 bytes Database mounted. ORA-01157: cannot identify/lock data file 6 - see DBWR trace file ORA-01110: data file 6: '/u01/app/oracle/oradata/xxx/xxx_data.dbf' When all continued the same, I erased the dbf files (rm xxx_data.dbf xxx_index.dbf), and recreated them using touch xxx_data.dbf. I also tried to recreate the tablespaces using `CREATE TABLESPACE DATA DATAFILE XXX_DATA.DBF` and got Database not open As I said, i don't know how bad this is, or how far i'm from gaining access to my database (well, to this SID at least, the others are working). I would imagine that a last resource would be to throw everything away, and recreating it, but I don't know how to, and I was hoping there's a less destructive solution. Any help will be greatly appreciated . Thanks in advance.

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  • How do i write task? (parallel code)

    - by acidzombie24
    I am impressed with intel thread building blocks. I like how i should write task and not thread code and i like how it works under the hood with my limited understanding (task are in a pool, there wont be 100 threads on 4cores, a task is not guaranteed to run because it isnt on its own thread and may be far into the pool. But it may be run with another related task so you cant do bad things like typical thread unsafe code). I wanted to know more about writing task. I like the 'Task-based Multithreading - How to Program for 100 cores' video here http://www.gdcvault.com/sponsor.php?sponsor_id=1 (currently second last link. WARNING it isnt 'great'). My fav part was 'solving the maze is better done in parallel' which is around the 48min mark (you can click the link on the left side). However i like to see more code examples and some API of how to write task. Does anyone have a good resource? I have no idea how a class or pieces of code may look after pushing it onto a pool or how weird code may look when you need to make a copy of everything and how much of everything is pushed onto a pool.

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  • Problem using SQLDataReader with Sybase ASE

    - by John K.
    We're developing a reporting application that uses asp.net-mvc (.net 4). We connect through DDTEK.Sybase middleware to a Sybase ASE 12.5 database. We're having a problem pulling data into a datareader (from a stored procedure). The stored procedure computes values (approximately 50 columns) by doing sums, counts, and calling other stored procedures. The problem we're experiencing is... certain (maybe 5% of the columns) come back with NULL or 0. If we debug and copy the SQL statement being used for the datareader and run it inside another SQL tool we get all valid values for all columns. conn = new SybaseConnection { ConnectionString = ConfigurationManager.ConnectionStrings[ConnectStringName].ToString() }; conn.Open(); cmd = new SybaseCommand { CommandTimeout = cmdTimeout, Connection = conn, CommandText = mainSql }; reader = cmd.ExecuteReader(); // AT THIS POINT IMMEDIATELY AFTER THE EXECUTEREADER COMMAND // THE READER CONTAINS THE BAD (NULL OR 0) DATA FOR THESE COLUMNS. DataTable schemaTable = reader.GetSchemaTable(); // AT THIS POINT WE CAN VIEW THE DATATABLE FOR THE SCHEMA AND IT APPEARS CORRECT // THE COLUMNS THAT DON'T WORK HAVE SPECIFICATIONS IDENTICAL TO THE COLUMNS THAT DO WORK Has anyone had problems like this using Sybase and ADO? Thanks, John K.

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  • Ideal directory structure for web application

    - by rno
    I'm about to create a user based website and will have to store photo, docs and other data for each user. If I take a silly number like 1 000 000 000 users, I believe than one folder with 1 000 000 000 won't be the fastest thing in the world! So I was thinking of creating something like 1st level : [a-z] 2nd level : [a-z] 3rd level : [a-z] Therefor bobby will be in /b/o/b/by But this also mean that it won't be spread equaly, because there will be very few user starting with a z and many more with a m,s,l ... so I was thinking of using a user id such as "000000000001", "000000000001" etc... 1st level : [000-999] 2nd level : [000-999] 3rd level : [000-999] therefore data of the user 000000000001 will be store in /data/000/000/000/001 then I will be sure to have a maximum of 1000 folder in each level. What do you guys think about it, what I should do or not do ? The server will be running Centos 5.4 with EXT3 on raid 1, if the I/O get's too bad i will probably go for a raid 10.

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  • How to Load external Div that has a dynamic content using ajax and jsp/servlets ?

    - by A.S al-shammari
    I need to use ajax feature to load external div element ( external jsp file) into the current page. That JSP page contains a dynamic content - e.g. content that is based on values received from the current session. I solved this problem , but I'm in doubt because I think that my solution is bad , or maybe there is better solution since I'm not expert. I have three files: Javascript function that is triggered when a element is clicked, it requests html data from a servlet: $("#inboxtable tbody tr").click(function(){ var trID = $(this).attr('id'); $.post("event?view=read",{id:trID}, function(data){ $("#eventContent").html(data); // load external file },"html"); // type }); The servlet "event" loads the data and generates HTML content using include method : String id = request.getParameter("id"); if (id != null) { v.add("Test"); v.add(id); session.setAttribute("readMessageVector", v); request.getRequestDispatcher("readMessage.jsp").include(request, response); } The readMessage jsp file looks like this: <p> Text: ${readMessageVector[0]} </p> <p> ID: ${readMessageVector[1]} </p> My questions Is this solution good enough to solve this problem - loading external jsp that has dynamic content ? Is there better solution ?

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  • How to get the most out of a 3 month intern?

    - by firoso
    We've got a software engineering intern coming in who's fairly competent and shows promise. There's one catch: we have him for 3 months full time and can't count on anything past that. He still has a year of school left, which is why we can't say for sure that we have him past 3 months. We have a specific project we're putting him on. How can we maximize his productivity while still giving him a positive learning experience? He wants to learn about development cycles and real-world software engineering. Anything that you think would be critical that you wish you had learned earlier? Nearly six months later: He's preformed admirably and even I have learned a lot from him. Thank you all for the input. Now I want to provide feedback to YOU! He has benefited most from sitting down and writing code. However, he has had a nasty history of bad software engineering practices which I'm trying to replace with good habits (properly finishing a method before moving on, not hacking code together, proper error channeling, etc). He has also really gained a lot by feeling involved in design decisions, even if most of the time they're related to my own design plans.

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  • How to emulate mod_rewrite in PHP

    - by Tyler Crompton
    I have a few URLs that I want to map to certain files via PHP. Currently, I am just using mod_rewrite in Apache. However, my application is getting too large for the rewriting to be done with regular expressions. So I created a file router.php that does the rewriting. I understand to do a redirect I could just send the Location: header. However, I don't always want to do a redirect. For example, I may want /api/item/ to map to the file /herp/derp.php relative to the document root. I need to preserve the HTTP method as well. "No problem," I thought. I made my .htaccess have the following snippet. RewriteEngine On RewriteRule ^api/item/$ /cgi-bin/router.php [L] And my router.php file looks as follows: <?php $uri = parse_url($_SERVER['REQUEST_URI']); $query = isset($uri['query']) ? $uri['query'] ? array(); // some code that modifies the query require_once "{$_SERVER['DOCUMENT_ROOT']}/herp/derp.php?" . http_build_query($query); ?> However, this doesn't work, because the OS is looking for a file named derp.php?some=query. How can I simulate a rewrite rule such as RewriteRule ^api/item/$ /herp/derp/ [L] in PHP. In other words, how do I tell the server to process a different URL than requested and preserve the query and HTTP method without causing a redirect? Note: Using variables set in router.php is less than desirable and is bad structure since it's only supposed to be responsible for handling URLs. I am open to using a light-weight third party solution.

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  • Access modifiers - Property on business objects - getting and setting

    - by Mike
    Hi, I am using LINQ to SQL for the DataAccess layer. I have similar business objects to what is in the data access layer. I have got the dataprovider getting the message #23. On instantiation of the message, in the message constructor, it gets the MessageType and makes a new instance of MessageType class and fills in the MessageType information from the database. Therefore; I want this to get the Name of the MessageType of the Message. user.Messages[23].MessageType.Name I also want an administrator to set the MessageType user.Messages[23].MessageType = MessageTypes.LoadType(3); but I don't want the user to publicly set the MessageType.Name. But when I make a new MessageType instance, the access modifier for the Name property is public because I want to set that from an external class (my data access layer). I could change this to property to internal, so that my class can access it like a public variable, and not allow my other application access to modify it. This still doesn't feel right as it seems like a public property. Are public access modifiers in this situation bad? Any tips or suggestions would be appreciated. Thanks.

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  • Is it possible to split HTML using DOMDocument?

    - by Lynn Adrianna
    Using DOMDocument, is it possible to split a block of HTML by text wrapped in tags and those that are not, while maintaining the order? Sorry, if this doesn't make sense. My example should make it clear. Let's say I have the following block of HTML: text1<b style="color:pink">text2</b>text3<b>text4</b> <b style="font-weight:bold">text5</b> Is it possible create an array as such: array( [0] => text1 [1] => <b style="color:pink">text2</b> [2] => text3 [3] => <b>text4</b> [4] => [5] => <b style="font-weight:bold">text5</b> ) Below is my current working solution, which uses a regular expression, to split the HTML. $tokens = preg_split('/(<b\b[^>]*>.*?<\/b>)/i', $html, null, PREG_SPLIT_DELIM_CAPTURE); However, I always read that it is a bad idea to parse HTML using regular expressions, so was just wondering if there is a better way.

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  • Is there a fundamental difference between malloc and HeapAlloc (aside from the portability)?

    - by Lambert
    Hi, I'm having code that, for various reasons, I'm trying to port from the C runtime to one that uses the Windows Heap API. I've encountered a problem: If I redirect the malloc/calloc/realloc/free calls to HeapAlloc/HeapReAlloc/HeapFree (with GetProcessHeap for the handle), the memory seems to be allocated correctly (no bad pointer returned, and no exceptions thrown), but the library I'm porting says "failed to allocate memory" for some reason. I've tried this both with the Microsoft CRT (which uses the Heap API underneath) and with another company's run-time library (which uses the Global Memory API underneath); the malloc for both of those works well with the library, but for some reason, using the Heap API directly doesn't work. I've checked that the allocations aren't too big (= 0x7FFF8 bytes), and they're not. The only problem I can think of is memory alignment; is that the case? Or other than that, is there a fundamental difference between the Heap API and the CRT memory API that I'm not aware of? If so, what is it? And if not, then why does the static Microsoft CRT (included with Visual Studio) take some extra steps in malloc/calloc before calling HeapAlloc? I'm suspecting there's a difference but I can't think of what it might be. Thank you!

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  • Animation is slow on iPhone

    - by Anthony Chan
    I'm developing an app that would display images and change them according to the user's action. I've created a subclass of UIView to contain an image, an index number and an array of image names. The code is like this: @interface CustomPic : UIView { UIImageView *pic; NSInteger index; NSMutableArray *picNames; //<-- an array of NSString } And in the implementation part, it has a method to change the image using a dissolve effect. - (void)nextPic { index++; if (index >= [picNames count]) { index = 0; } UIImageView *temp = pic; pic.image = [UIImage imageNamed:[picNames objectAtIndex:index]]; temp.alpha = 0; [UIView beginAnimations:nil context:nil]; [UIView setAnimationCurve:UIViewAnimationCurveEaseOut]; [UIView setAnimationDuration:0.25]; pic.alpha = 0; temp.alpha = 1; [UIView commitAnimations]; } In the viewController, there are several CustomPic which would change the images depends on users' choice. The images would change as expected with the fade in/out effect, but the animation performance is really bad. I've tested it on an iPhone 3G, the Instruments shows that the animation is only 2-3FPS! I tried many methods to simplify and modify the codes but with no hope. Is there something wrong in my code or in my concept? Thanks for any help. P.S. all the images are 320*480 PNGs with a max size of 15KB.

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  • What is wrong with locking non-static fields? What is the correct way to lock a particular instance?

    - by smartcaveman
    Why is it considered bad practice to lock non-static fields? And, if I am not locking non-static fields, then how do I lock an instance method without locking the method on all other instances of the same or derived class? I wrote an example to make my question more clear. public abstract class BaseClass { private readonly object NonStaticLockObject = new object(); private static readonly object StaticLockObject = new object(); protected void DoThreadSafeAction<T>(Action<T> action) where T: BaseClass { var derived = this as T; if(derived == null) { throw new Exception(); } lock(NonStaticLockObject) { action(derived); } } } public class DerivedClass :BaseClass { private readonly Queue<object> _queue; public void Enqueue(object obj) { DoThreadSafeAction<DerivedClass>(x=>x._queue.Enqueue(obj)); } } If I make the lock on the StaticLockObject, then the DoThreadSafeAction method will be locked for all instances of all classes that derive from BaseClass and that is not what I want. I want to make sure that no other threads can call a method on a particular instance of an object while it is locked.

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  • Dynamic/Generic ViewModelBase?

    - by Shimmy
    I am learning MVVM now and I understand few things (more than but few are here..): Does every model potentially exposed (thru a VM) to the View is having a VM? For example, if I have a Contact and Address entity and each contact has an Addresses (many) property, does it mean I have to create a ContactViewModel and an AddressViewModel etc.? Do I have to redeclare all the properties of the Model again in the ViewModel (i.e. FirstName, LastName blah blah)? why not have a ViewModelBase and the ContactViewMode will be a subclass of ViewModelBase accessing the Entity's properties itself? and if this is a bad idea that the View has access to the entity (please explain why), then why not have the ViewModelBase be a DynamicObject (view the Dictionary example @ the link page), so I don't have to redeclare all the properties and validation over and over in the two tiers (M & VM) - because really, the View is anyway accessing the ViewModel's fields via reflection anyway. I think MVVM was the hardest technology I've ever learned. it doesn't have out-the-box support and there are to many frameworks and methods to achieve it, and in the other hand there is no arranged way to learn it (as MVC for instance), learning MVVM means browsing and surfing around trying to figure out what's better. Bottom line, what I mean by this section is please go and vote to MSFT to add MVVM support in the BCL and generators for VMs and Vs according to the Ms. Thanks

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