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  • jQuery set selected value in option box once the box has been loaded

    - by Maarten
    I want to preset the value of a selectbox based on a hidden field. I need this after an error has been detected in a form to avoid the user having to set the value themselves again. I do this by setting the value of a hidden field server side. The problem I have seems to be that the select box isn't done yet at the time I try to set the selected value. Anyone know how to solve this (possibly in a very different way?) <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.js"></script> <script type="text/javascript" charset="utf-8"> $(function(){ // this functions loads the state select box with states if a country with states is selected $("select#countries").change(function(){ $.getJSON("/ajax/exhibition/getstates.php?idCountry="+$("select#countries").val(), function(j){ var options = ''; $.each(j, function(key, value){ options += '<option value="' + key + '">' + value + '</option>'; }); $("select#state").html(options); }); }); }); $(document).ready(function(){ // preset the state select box on page ready $('select#countries').change(); // set the selected value of the state select box var foo = $('#statepreset').val(); $("select#state option[value="+foo+"]").attr('selected', 'selected'); }); </script>

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  • How can I improve my real-time behavior in multi-threaded app using pthreads and condition variables

    - by WilliamKF
    I have a multi-threaded application that is using pthreads. I have a mutex() lock and condition variables(). There are two threads, one thread is producing data for the second thread, a worker, which is trying to process the produced data in a real time fashion such that one chuck is processed as close to the elapsing of a fixed time period as possible. This works pretty well, however, occasionally when the producer thread releases the condition upon which the worker is waiting, a delay of up to almost a whole second is seen before the worker thread gets control and executes again. I know this because right before the producer releases the condition upon which the worker is waiting, it does a chuck of processing for the worker if it is time to process another chuck, then immediately upon receiving the condition in the worker thread, it also does a chuck of processing if it is time to process another chuck. In this later case, I am seeing that I am late processing the chuck many times. I'd like to eliminate this lost efficiency and do what I can to keep the chucks ticking away as close to possible to the desired frequency. Is there anything I can do to reduce the delay between the release condition from the producer and the detection that that condition is released such that the worker resumes processing? For example, would it help for the producer to call something to force itself to be context switched out? Bottom line is the worker has to wait each time it asks the producer to create work for itself so that the producer can muck with the worker's data structures before telling the worker it is ready to run in parallel again. This period of exclusive access by the producer is meant to be short, but during this period, I am also checking for real-time work to be done by the producer on behalf of the worker while the producer has exclusive access. Somehow my hand off back to running in parallel again results in significant delay occasionally that I would like to avoid. Please suggest how this might be best accomplished.

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  • Identifying and Resolving Oracle ITL Deadlock

    - by Allan
    I have an Oracle DB package that is routinely causing what I believe is an ITL (Interested Transaction List) deadlock. The relevant portion of a trace file is below. Deadlock graph: ---------Blocker(s)-------- ---------Waiter(s)--------- Resource Name process session holds waits process session holds waits TM-0000cb52-00000000 22 131 S 23 143 SS TM-0000ceec-00000000 23 143 SX 32 138 SX SSX TM-0000cb52-00000000 30 138 SX 22 131 S session 131: DID 0001-0016-00000D1C session 143: DID 0001-0017-000055D5 session 143: DID 0001-0017-000055D5 session 138: DID 0001-001E-000067A0 session 138: DID 0001-001E-000067A0 session 131: DID 0001-0016-00000D1C Rows waited on: Session 143: no row Session 138: no row Session 131: no row There are no bit-map indexes on this table, so that's not the cause. As far as I can tell, the lack of "Rows waited on" plus the "S" in the Waiter waits column likely indicates that this is an ITL deadlock. Also, the table is written to quite often (roughly 8 insert or updates concurrently, as often as 240 times a minute), so and ITL deadlock seems like a strong possibility. I've increased the INITRANS parameter of the table and it's indexes to 100 and increased the PCT_FREE on the table from 10 to 20 (then rebuilt the indexes), but the deadlocks are still occurring. The deadlock seems to happen most often during an update, but that could just be a coincidence, as I've only traced it a couple of times. My questions are two-fold: 1) Is this actually an ITL deadlock? 2) If it is an ITL deadlock, what else can be done to avoid it?

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  • how can I add a custom non-DataTable column to my DataView, in a winforms ADO.net application?

    - by Greg
    Hi, How could I (/is it possible) to add a custom column to my DataView, and in this column display the result of a specific calculation. That is, I currently have a dataGridView which has a binding to a DataView, based on the DataTable from my database. I'd like to add an additional column to the dataGridView to display a number which is calculated by looking at this current row plus it's children row. In other words the info for the column isn't just derivable from the row data itself. Specific questions might be: a) where to add the column itself? to the DataView I assume? b) which method / event to trigger the re-calculation of the value of this custom column from ( / how do I control this) Thanks PS. I've also noted if I use the following code/approach I get a infinite loop... // Custom Items DataColumn dc = new DataColumn("OverallSize", typeof(long)); DT_Webfiles.Columns.Add(dc); DT_Webfiles.RowChanged += new DataRowChangeEventHandler(DT_Row_Changed); private static void DT_Row_Changed(object sender, DataRowChangeEventArgs e) { e.Row["OverallSize"] = e.Row["OverallSize"] ?? 0; e.Row["OverallSize"] = (long)e.Row["OverallSize"] + 1; } What other approach could avoid this looping. i.e. currently I'm saying update the value of the custom column when the row changes, however after then changing the row it triggers antoher 'row has changed' event...

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  • Force full garbage collection when memory occupation goes beyond a certain threshold

    - by Silvio Donnini
    I have a server application that, in rare occasions, can allocate large chunks of memory. It's not a memory leak, as these chunks can be claimed back by the garbage collector by executing a full garbage collection. Normal garbage collection frees amounts of memory that are too small: it is not adequate in this context. The garbage collector executes these full GCs when it deems appropriate, namely when the memory footprint of the application nears the allotted maximum specified with -Xmx. That would be ok, if it wasn't for the fact that these problematic memory allocations come in bursts, and can cause OutOfMemoryErrors due to the fact that the jvm is not able to perform a GC quickly enough to free the required memory. If I manually call System.gc() beforehand, I can prevent this situation. Anyway, I'd prefer not having to monitor my jvm's memory allocation myself (or insert memory management into my application's logic); it would be nice if there was a way to run the virtual machine with a memory threshold, over which full GCs would be executed automatically, in order to release very early the memory I'm going to need. Long story short: I need a way (a command line option?) to configure the jvm in order to release early a good amount of memory (i.e. perform a full GC) when memory occupation reaches a certain threshold, I don't care if this slows my application down every once in a while. All I've found till now are ways to modify the size of the generations, but that's not what I need (at least not directly). I'd appreciate your suggestions, Silvio P.S. I'm working on a way to avoid large allocations, but it could require a long time and meanwhile my app needs a little stability

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  • Is This a Valid Way to Use Blocks in Objective-C?

    - by Carter
    I've been building a HTTP client that uses web services to synchronize information between the client and server. I've been using Blocks and NSURLConnection to achieve this on the client side, but I'm getting frequent EXC_BAD_ACCESS crashes in objc_msgSend(). From what I understand, this usually means that a stored block that has fallen off the stack has been called. I think I've coded things correctly to avoid this, but I'm still stuck. Here is conceptually what my code is doing. It starts by calling "synchronizeWithWebServer". That method invokes "listRootObjectsOnServerWithBlock:" which takes in a block to be called when the method returns. "listRootObjectsOnServersWithBlock:" initiates a NSURLConnection to the web server asynchronously. It to expects a block to be called when it returns. Inside that block I want to be able to execute the original Block (so aptly named 'block'). This is only a simplified version of my code. The real synchronization process is more complex but it's mostly more of the same as what you see below. Sometimes the code works perfectly, but about 80% of the time it crashes very early on in the routine. It seems to be more vulnerable to crashing when my data set gets larger. - (void)synchronizeWithWebServer { [self listRootObjectsOnServerWithBlock:^(NSArray *results, NSError *error) { //Iterate over result objects and perform some other similar routines. }]; } - (void)listRootObjectsOnServerWithBlock:(void (^)(NSArray *results, NSError *error))block { //Create NSURLRequest Here //Create connection asynchronously. block = [block copy]; [NSURLConnection sendAsynchronousRequest:urlRequest queue:[NSOperationQueue currentQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){ //Parse response from web server (stored in NSData *data) NSArray *results = ..... //Call 'block' block(results, error); [block release]; }]; }

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  • Trouble binding WPF Menu to ItemsSource

    - by chaiguy
    I would like to avoid having to build a menu manually in XAML or code, by binding to a list of ICommand-derived objects. However, I'm experiencing a bit of a problem where the resulting menu has two levels of menu-items (i.e. each MenuItem is contained in a MenuItem): My guess is that this is happening because WPF is automatically generating a MenuItem for my binding, but the "viewer" I'm using actually already is a MenuItem (it's derived from MenuItem): <ContextMenu x:Name="selectionContextMenu" ItemsSource="{Binding Source={x:Static OrangeNote:Note.MultiCommands}}" ItemContainerStyleSelector="{StaticResource separatorStyleSelector}"> <ContextMenu.ItemTemplate> <DataTemplate> <Viewers:NoteCommandMenuItemViewer CommandParameter="{Binding Source={x:Static OrangeNote:App.Screen}, Path=SelectedNotes}" /> </DataTemplate> </ContextMenu.ItemTemplate> </ContextMenu> (The ItemContainerStyleSelector is from http://bea.stollnitz.com/blog/?p=23, which allows me to have Separator elements inside my bound source.) So, the menu is bound to a collection of ICommands, and each item's CommandParameter is set to the same global target (which happens to be a collection, but that's not important). My question is, is there any way I can bind this such that WPF doesn't automatically wrap each item in a MenuItem?

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  • IRC Server configuration possibilities

    - by Katai
    I need to know a couple of things, concerning IRC servers that I couldnt directly find out over google (or werent clear enough for me to be sure if it actually works) I'm working at a larger community site, and wanted to deliver an in-page chat. Since it would be a nice feature to let people access it from outside too, over their own clients, I tought implementing an IRC Server would be the best solution (probably dedicated, I'll have to teach myself a couple of things for that) I plan to include a Web-based IRC client over an APE Client / Server. The problem is, I want to strip down the user rights, to disallow many functionalities that IRC would offer: Change of nicknames: The user logs in over the Page login, and I'll automatically create an IRC auth for this user with that password. So basically, he would connect to the IRC client over a button. And after connecting, he shouldnt be able to change his nickname at all Creating channels: I want the possibility to create channels, but not from 'normal' users. Basically, I would prefer to set up basic channels that are public, and if a user really creates an own channel, that one should be private and via invitation (is that possible?) Private conversations: private conversations should be filtered out from the allaround IRC client, into separate 'in-browser-windows' that I create over JS. I guess I just have to filter the stuff coming from IRC - or is there a better solution to that? Only 'registered' users have access: Like I said, if someone registers on the page, I would like to create an IRC 'account' for him. Users that arent registered on the page, cant access the IRC server at all (or get thrown out). Mainly to avoid spammers or bots from outside. Is this stuff solvable over IRC? I've read some FAQ's and Instructions for IRC OP's and servers, but I couldnt find a clear answer - it seems that everyone can do pretty much everything - I would like to configure it in a way that user possibilities are more cut down. Basically, giving users the possibility to chat, but not more. So the Question basically is, how possible / solvable this issues are allaround, or if I have to find other solutions for this.

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  • Relay WCF Service

    - by Matt Ruwe
    This is more of an architectural and security question than anything else. I'm trying to determine if a suggested architecture is necessary. Let me explain my configuration. We have a standard DMZ established that essentially has two firewalls. One that's external facing and the other that connects to the internal LAN. The following describes where each application tier is currently running. Outside the firewall: Silverlight Application In the DMZ: WCF Service (Business Logic & Data Access Layer) Inside the LAN: Database I'm receiving input that the architecture is not correct. Specifically, it has been suggested that because "a web server is easily hacked" that we should place a relay server inside the DMZ that communicates with another WCF service inside the LAN which will then communicate with the database. The external firewall is currently configured to only allow port 443 (https) to the WCF service. The internal firewall is configured to allow SQL connections from the WCF service in the DMZ. Ignoring the obvious performance implications, I don't see the security benefit either. I'm going to reserve my judgement of this suggestion to avoid polluting the answers with my bias. Any input is appreciated. Thanks, Matt

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  • Optimal Serialization of Primitive Types

    - by Greg Dean
    We are beginning to roll out more and more WAN deployments of our product (.Net fat client w/ IIS hosted Remoting backend). Because of this we are trying to reduce the size of the data on the wire. We have overridden the default serialization by implementing ISerializable (similar to this), we are seeing anywhere from 12% to 50% gains. Most of our efforts focus on optimizing arrays of primitive types. I would like to know if anyone knows of any fancy way of serializing primitive types, beyond the obvious? For example today we serialize an array of ints as follows: [4-bytes (array length)][4-bytes][4-bytes] Can anyone do significantly better? The most obvious example of a significant improvement, for boolean arrays, is putting 8 bools in each byte, which we already do. Note: Saving 7 bits per bool may seem like a waste of time, but when you are dealing with large magnitudes of data (which we are), it adds up very fast. Note: We want to avoid general compression algorithms because of the latency associated with it. Remoting only supports buffered requests/responses(no chunked encoding). I realize there is a fine line between compression and optimal serialization, but our tests indicate we can afford very specific serialization optimizations at very little cost in latency. Whereas reprocessing the entire buffered response into new compressed buffer is too expensive.

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  • Jquery Tools: Scrollable - onBeforeSeek & onSeek toggle child div

    - by Rick
    I'm scrolling some panels which contain some youtube clips using Jquery Tools Scrollable. I'd like to hide them during the transition to avoid a jerky animation. Markup: <div id="panel_items"> <div id="wrap"> <div class="event"> <div class="header">Event 1</div><!-- Header is always displayed --> <div class="youtube">youtube clips</div><!-- hide during transition, then show --> </div> <div class="event"> <div class="header">Event 2</div> <div class="youtube" style="display: none">More youtube clips</div> </div> </div> </div> Current JS: $("#panel_items").scrollable({ onBeforeSeek: function() { console.log("hide .child .youtube"); }, onSeek: function() { console.log("Show child .youtube"); } }); Bonus question: How can I automatically set the height of #panel_items to match the current panel height (.event)? Thank you.

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  • Virtual Lan on the Cloud -- Help Confirm my understanding?

    - by marfarma
    [Note: Tried to post this over at ServerFault, but I don't have enough 'points' for more than one link. Powers that be, move this question over there.] Please give this a quick read and let me know if I'm missing something before I start trying to make this work. I'm not a systems admin professional, and I'd hate to end up banging my head into the wall if I can avoid it. Goals: Create a 'road-warrior' capable star shaped virtual LAN for consultants who spend the majority of their time on client sites, and who's firm has no physical network or servers. Enable CIFS access to a cloud-server based installation of Alfresco Allow Eventual implementation of some form of single-sign-on ( OpenLDAP server ) access to Alfresco and other server applications implemented in the future Given: All Servers will live in the public internet cloud (Rackspace Cloud Servers) OpenVPN Server will be a Linux disto, probably Ubuntu 9.x, installed on same server as Alfresco (at least to start) Staff will access server applications and resources from client sites, hotels, trains, planes, coffee shops or their homes over various ISP, using their company laptops or personal home desktops. Based on my Research thus far, to accomplish this, I'll need: OpenVPN with Bridging Enabled to create a star shaped "virtual" LAN http://openvpn.net/index.php/open-source/documentation/miscellaneous/76-ethernet-bridging.html A Road Warrior Network Configuration, as described in this Shorewall article (lower down the page) http://www.shorewall.net/OPENVPN.html Configure bridge addressesing (probably DHCP) http://openvpn.net/index.php/open-source/faq.html#bridge-addressing Configure CIFS / Samba to accept VPN IP address http://serverfault.com/questions/137933/howto-access-samba-share-over-vpn-tunnel Set up Client software, with keys configured for access (potentially through a OpenVPN-Sa client portal) http://www.openvpn.net/index.php/access-server/download-openvpn-as/221-installation-overview.html

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  • javascript RegEx hashtag matching #foo and #foo-fåäö but not http://this.is/no#hashtag

    - by Simon B.
    Currently we're using javascript new RegExp('#[^,#=!\s][^,#=!\s]*') (see [1]) and it mostly works, except that it also matches URLs with anchors like http://this.is/no#hashtag and also we'd rather avoid matching foo#bar Some attempts have been made with look-ahead but it doesn't seem to work, or that I just don't get it. With the below source text: #public #writable #kommentarer-till-beta -- all these should be matched Verkligen #bra jobbat! T ex #kommentarer till #artiklar och #blogginlägg, kool. -- mixed within text http://this.is/no#hashtag -- problem xxy#bar -- We'd prefer not matching this one, and... #foo=bar =foo#bar -- we probably shouldn't match any of those either. #foo,bar #foo;bar #foo-bar #foo:bar -- We're flexible on whether these get matched in part or in full . We'd like to get below output: (showing $ instead of <a class=tag href=.....>...</a> for readability reasons) $ $ $ -- all these should be matched Verkligen $ jobbat! T ex $ till $ och $, kool. -- mixed within text http://this.is/no$ -- problem xxy$ -- We'd prefer not matching this one, and... $=bar =foo$ -- we probably shouldn't match any of those either. $,bar $ $ $ -- We're flexible on whether these get matched in part or in full [1] http://github.com/ether/pad/blob/master/etherpad/src/plugins/twitterStyleTags/hooks.js

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  • Per-pixel per-component alpha blending in Windows

    - by Crend King
    I have a 24-bit bitmaps with R, G, B color channels and a 24-bit bitmap with R, G, B alpha channels. I want to alpha blend the first bitmap to a HDC in GDI or RenderTarget in Direct2D with the alpha channels respectively. For example, suppose for one pixel, the bitmap color is (192, 192, 192), the HDC color is (0, 255, 255) and the alpha channels are (30, 40, 50). The final HDC color should be (22, 245, 242). I know I can BitBlt the HDC to a memory HDC first, do alpha blending by manually calculating the color of each pixel and finally BitBlt back. I just want to avoid the additional blitting and leave APIs do their job (faster since they are in kernel space). The first idea comes to my mind is to split the source bitmap into 3 red-only, green-only and blue-only 8-bit bitmaps, do normal alpha blending, then composite the 3 output bitmaps into the HDC. But I don't find a way to do the splitting and composition natively in Windows (would Direct2D layer help?). Also, the splitting and compositing may require many additional copying. The performance overhead would be too high. Or maybe do the alpha blending in 3 passes. Each pass apply the blending for one channel, while maintaining the other 2 unchanged. Thanks for any comment. EDIT: I found this question, and the answer should be good reference to this problem. However, besides AC_SRC_OVER, there is no other blending operation supported. Why don't Microsoft improve their API?

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  • Matplotlib canvas drawing

    - by Morgoth
    Let's say I define a few functions to do certain matplotlib actions, such as def dostuff(ax): ax.scatter([0.],[0.]) Now if I launch ipython, I can load these functions and start a new figure: In [1]: import matplotlib.pyplot as mpl In [2]: fig = mpl.figure() In [3]: ax = fig.add_subplot(1,1,1) In [4]: run functions # run the file with the above defined function If I now call dostuff, then the figure does not refresh: In [6]: dostuff(ax) I have to then explicitly run: In [7]: fig.canvas.draw() To get the canvas to draw. Now I can modify dostuff to be def dostuff(ax): ax.scatter([0.],[0.]) ax.get_figure().canvas.draw() This re-draws the canvas automatically. But now, say that I have the following code: def dostuff1(ax): ax.scatter([0.],[0.]) ax.get_figure().canvas.draw() def dostuff2(ax): ax.scatter([1.],[1.]) ax.get_figure().canvas.draw() def doboth(ax): dostuff1(ax) dostuff2(ax) ax.get_figure().canvas.draw() I can call each of these functions, and the canvas will be redrawn, but in the case of doboth(), it will get redrawn multiple times. My question is: how could I code this, such that the canvas.draw() only gets called once? In the above example it won't change much, but in more complex cases with tens of functions that can be called individually or grouped, the repeated drawing is much more obvious, and it would be nice to be able to avoid it. I thought of using decorators, but it doesn't look as though it would be simple. Any ideas?

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  • Scalaz: request for use case for Cokleisli composition

    - by oxbow_lakes
    This question isn't meant as flame-bait! As it might be apparent, I've been looking at Scalaz recently. I'm trying to understand why I need some of the functionality that the library provides. Here's something: import scalaz._ import Scalaz._ type NEL[A] = NonEmptyList[A] val NEL = NonEmptyList I put some println statements in my functions to see what was going on (aside: what would I have done if I was trying to avoid side effects like that?). My functions are: val f: NEL[Int] => String = (l: NEL[Int]) => {println("f: " + l); l.toString |+| "X" } val g: NEL[String] => BigInt = (l: NEL[String]) => {println("g: " + l); BigInt(l.map(_.length).sum) } Then I combine them via a cokleisli and pass in a NEL[Int] val k = cokleisli(f) =>= cokleisli(g) println("RES: " + k( NEL(1, 2, 3) )) What does this print? f: NonEmptyList(1, 2, 3) f: NonEmptyList(2, 3) f: NonEmptyList(3) g: NonEmptyList(NonEmptyList(1, 2, 3)X, NonEmptyList(2, 3)X, NonEmptyList(3)X) RES: 57 The RES value is the character count of the (String) elements in the final NEL. Two things occur to me: How could I have known that my NEL was going to be reduced in this manner from the method signatures involved? (I wasn't expecting the result at all) What is the point of this? Can a reasonably simple and easy-to-follow use case be distilled for me? This question is a thinly-veiled plea for some lovely person like retronym to explain how this powerful library actually works.

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  • Copy data from different worksheet to a master worksheet but no duplicates

    - by sam
    hi all, i want to clarify my initial question for a possible solutions from any savior out there. Say i have 3 excel sheets one for each user for data entry located in separate workbooks to avoid excel share workbook problems. I also have a master sheet in another workbook where i want individual data enter on those sheets precisely sheets 1 should copy to the next available row of sheet 1 in the master sheet as the users enter them. i need a vba code that can copy each record without copying a duplicate row in the master sheet but highlight the duplicate row and lookup the initial record in a master sheet and return the name of the Imputer looking up the row say column ( I) where each user sign there initials after every row of entry like below. All 4 worksheets are formatted as below: lastname account cardno. type tran amount date location comments initials JAME 65478923 1975 cash 500 4/10/2010 miles st. this acct is resolve MLK BEN 52436745 1880 CHECK 400 4/12/2010 CAREY ST Ongoing investigation MLK JAME 65478923 1975 cash 500 4/10/2010 miles st. this acct is resolve MLK I need the vba to recognize duplicates only if the account number and the card number matches the initial records. So if the duplicates exist a pop up message should be display that a duplicates exist and return the initial Imputer say MLK in COLUMN( I) to any user inputting in the individual worksheets other than warehouse sheets (master). So please any idea will be appreciated.

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  • How to catch a division by zero?

    - by Cristian Castiblanco
    I have a large mathematical expression that has to be created dinamically. So, for example, once I have parsed "something" the result will be a string like: "$foo+$bar/$baz";. So, for calculating the result of that expression I'm using the eval function... something like this: eval("\$result = $expresion;"); echo "The result is: $result"; The problem here is that sometimes I get errors that says there was a division by zero, and I don't know how to catch that Exception. I have tried things like: eval("try{\$result = $expresion;}catch(Exception \$e){\$result = 0;}"); echo "The result is: $result"; Or: try{ eval("\$result = $expresion;"); } catch(Exception $e){ $result = 0; } echo "The result is: $result"; But it does not work. So, how can I avoid that my application crashes when there is a division by zero?

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  • How to temporarily replace one primitive type with another when compiling to different targets in c#

    - by Keith
    How to easily/quickly replace float's for doubles (for example) for compiling to two different targets using these two particular choices of primitive types? Discussion: I have a large amount of c# code under development that I need to compile to alternatively use float, double or decimals depending on the use case of the target assembly. Using something like “class MYNumber : Double” so that it is only necessary to change one line of code does not work as Double is sealed, and obviously there is no #define in C#. Peppering the code with #if #else statements is also not an option, there is just too much supporting Math operators/related code using these particular primitive types. I am at a loss on how to do this apparently simple task, thanks! Edit: Just a quick comment in relation to boxing mentioned in Kyles reply: Unfortunately I need to avoid boxing, mainly since float's are being chosen when maximum speed is required, and decimals when maximum accuracy is the priority (and taking the 20x+ performance hit is acceptable). Boxing would probably rules out decimals as a valid choice and defeat the purpose somewhat. Edit2: For reference, those suggesting generics as a possible answer to this question note that there are many issues which count generics out (at least for our needs). For an overview and further references see Using generics for calculations

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  • Looking for streaming xml pretty printer in C/C++ using expat or libxml2

    - by Mark Zeren
    I'm looking for a streaming xml pretty printer for C/C++ that's either self contained or that uses libxml2 or expat. I've searched a bit and not found one. It seems like something that would be generally useful. Am I missing an obvious tool that does this? Background: I have a library that outputs xml without whitespace all on one line. In some cases I'd like to pretty print that output. I'm looking for a BSD-ish licensed C/C++ library or sample code that will take a raw xml byte stream and pretty print it. Here's some pseudo code showing one way that I might use this functionality: void my_write(const char* buf, int len); PrettyPrinter pp(bind(&my_write)); while (...) { // ... get some more xml ... const char* buf = xmlSource.get_buf(); int len = xmlSource.get_buf_len(); int written = pp.write(buf, len); // calls my_write with pretty printed xml // ... error handling, maybe call write again, etc. ... } I'd like to avoid instantiating a DOM representation. I already have dependencies on the expat and libxml2 shared libraries, and I'd rather not add any more shared library dependencies.

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  • Sharing large objects between ruby processes without a performance hit

    - by Gdeglin
    I have a Ruby hash that reaches approximately 10 megabytes if written to a file using Marshal.dump. After gzip compression it is approximately 500 kilobytes. Iterating through and altering this hash is very fast in ruby (fractions of a millisecond). Even copying it is extremely fast. The problem is that I need to share the data in this hash between Ruby on Rails processes. In order to do this using the Rails cache (file_store or memcached) I need to Marshal.dump the file first, however this incurs a 1000 millisecond delay when serializing the file and a 400 millisecond delay when serializing it. Ideally I would want to be able to save and load this hash from each process in under 100 milliseconds. One idea is to spawn a new Ruby process to hold this hash that provides an API to the other processes to modify or process the data within it, but I want to avoid doing this unless I'm certain that there are no other ways to share this object quickly. Is there a way I can more directly share this hash between processes without needing to serialize or deserialize it? Here is the code I'm using to generate a hash similar to the one I'm working with: @a = [] 0.upto(500) do |r| @a[r] = [] 0.upto(10_000) do |c| if rand(10) == 0 @a[r][c] = 1 # 10% chance of being 1 else @a[r][c] = 0 end end end @c = Marshal.dump(@a) # 1000 milliseconds Marshal.load(@c) # 400 milliseconds

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  • Sanitize a string with non-alphanum repetition

    - by Toto
    I need to sanitize article titles when (creative) users try to "attract attention" with some non-alphanum repetition. Exemples: Buy my product !!!!!!!!!!!!!!!!!!!!!!!! Buy my product !? !? !? !? !? !? Buy my product !!!!!!!!!.......!!!!!!!! Buy my product <----------- Some acceptable solution would be to reduce the repetition of non-alphanum to 2. So I would get: Buy my product !! Buy my product !? !? Buy my product !!..!! Buy my product <-- This solution did not work that well: preg_replace('/(\W{2,})(?=\1+)/', '', $title) Any idea how to do it in PHP with regex? Other better solution is also welcomed (I cannot strip all the non-alphanum characters as they can make sense). Edit: the objective is only to avoid most common issues. The other creative cases will be sanitized manually or sanitized with an other regex.

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  • Simplest possible voting/synchronization algorithm

    - by Domchi
    What would be a simplest algorithm one or more people could use to decide who of them should perform some task? There is one task, which needs to be done only once, and one or more people. People can speak, that is, send messages one to another. Communication must be minimal, and all people use the exact same algorithm. One person saying "I'm doing it" is not good enough since two persons may say it at a same time. Simplest that comes to my mind is that each person says a number and waits a bit. If somebody responds in that time, the person with lower number "wins" and does the task. If nobody responds, person says that she's doing it and does it. When she says that she does it, everybody else backs off. This should be enough to avoid two persons doing the task in the same time (since there is wait/handhake period), but might need a "second round" if both persons say the same number. Is there something simpler? For those curious, I'm trying to synchronize several copies of SecondLife LSL script to do something only once.

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  • rails, mysql charsets & encoding: binary

    - by Benjamin Vetter
    Hi, i've a rails app that runs using utf-8. It uses a mysql database, all tables with mysql's default charset and collation (i.e. latin1). Therefore the latin1 tables contain utf-8 data. Sure, that's not nice, but i'm not really interested in it. Everything works fine, because the connection encoding is latin1 as well and therefore mysql does not convert between charsets. Only one problem: i need a utf-8 fulltext index for one table: mysql> show create table autocompletephrases; ... AUTO_INCREMENT=310095 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci But: I don't want to convert between charsets in my rails app. Therefore I would like to know if i could just set config/database.yml production: adapter: mysql >>>> encoding: binary ... which just calls SET NAMES 'binary' when connecting to mySQL. It looks like it works for my case, because i guess it forces mysql to -not- convert between charsets (mySQL docs). Does anyone knows about problems about doing this? Any side-effects? Or do you have any other suggestions? But i'd like to avoid converting my whole database to utf-8. Many Thanks! Benjamin

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  • Does my API design violate RESTful principles?

    - by peta
    Hello everybody, I'm currently (I try to) designing a RESTful API for a social network. But I'm not sure if my current approach does still accord to the RESTful principles. I'd be glad if some brighter heads could give me some tips. Suppose the following URI represents the name field of a user account: people/{UserID}/profile/fields/name But there are almost hundred possible fields. So I want the client to create its own field views or use predefined ones. Let's suppose that the following URI represents a predefined field view that includes the fields "name", "age", "gender": utils/views/field-views/myFieldView And because field views are kind of higher logic I don't want to mix support for field views into the "people/{UserID}/profile/fields" resource. Instead I want to do the following: utils/views/field-views/myFieldView/{UserID} Though Leonard Richardson & Sam Ruby state in their book "RESTful Web Services" that a RESTful design is somehow like an "extreme object oriented" approach, I think that my approach is object oriented and therefore accords to RESTful principles. Or am I wrong? When not: Are such "object oriented" approaches generally encouraged when used with care and in order to avoid query-based REST-RPC hybrids? Thanks for your feedback in advance, peta

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