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  • Perl XML SAX parser emulating XML::Simple record for record

    - by DVK
    Short Q summary: I am looking a fast XML parser (most likely a wrapper around some standard SAX parser) which will produce per-record data structure 100% identical to those produced by XML::Simple. Details: We have a large code infrastructure which depends on processing records one-by-one and expects the record to be a data structure in a format produced by XML::Simple since it always used XML::Simple since early Jurassic era. An example simple XML is: <root> <rec><f1>v1</f1><f2>v2</f2></rec> <rec><f1>v1b</f1><f2>v2b</f2></rec> <rec><f1>v1c</f1><f2>v2c</f2></rec> </root> And example rough code is: sub process_record { my ($obj, $record_hash) = @_; # do_stuff } my $records = XML::Simple->XMLin(@args)->{root}; foreach my $record (@$records) { $obj->process_record($record) }; As everyone knows XML::Simple is, well, simple. And more importantly, it is very slow and a memory hog - due to being a DOM parser and needing to build/store 100% of data in memory. So, it's not the best tool for parsing an XML file consisting of large amount of small records record-by-record. However, re-writing the entire code (which consist of large amount of "process_record"-like methods) to work with standard SAX parser seems like an big task not worth the resources, even at the cost of living with XML::Simple. What I'm looking for is an existing module which will probably be based on a SAX parser (or anything fast with small memory footprint) which can be used to produce $record hashrefs one by one based on the XML pictured above that can be passed to $obj->process_record($record) and be 100% identical to what XML::Simple's hashrefs would have been.

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  • How does real-time collaboration with multiple clients work in a system using operation transformati

    - by Saikat Chakrabarti
    I just finished reading High-Latency, Low-Bandwidth Windowing in the Jupiter Collaboration System and I mostly followed everything until part 6: global consistency. This part describes how the system described in the paper can be extended to accomodate for multiple clients connected to the server. However, the explanation is very short and essentially says the system will work if the central server merely forwards client messages to all the other clients. I don't really understand how this works though. What state vector would be sent in the message that is sent to all the other clients? Does the server maintain separate state vectors for each client? Does it maintain a separate copy of the widgets locally for each client? The simple example I can think of is this setup: imagine client A, server, and client B with client A and client B both connected to the server. To start, all three have the state object "ABCD". Then, client A sends the message "insert character F at position 0" at the same time client B sends the message "insert character G at position 0" to the server. It seems like simply relaying client A's message to client B and vice versa doesn't actually handle this case. So what exactly does the server do?

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  • Perl program - Dynamic Bootstrapping code

    - by mgj
    Hi.. I need to understand the working of this particular program, It seems to be quite complicated, could you please see if you could help me understanding what this program in Perl does, I am a beginner so I hardly can understand whats happening in the code given on the following link below, Any kind of guidance or insights wrt this program is highly appreciated. Thank you...:) This program is called premove.pl.c Its associated with one more program premove.pl, Its code looks like this: #!perl open (newdata,">newdata.txt") || die("cant create new file\n");#create passwd file $linedata = ""; while($line=<>){ chomp($line); #chop($line); print newdata $line."\n"; } close(newdata); close(olddata); __END__ I am even not sure how to run the two programs mentioned here. I wonder also what does the extension of the first program signify as it has "pl.c" extension, please let me know if you know what it could mean. I need to understand it asap thats why I am posting this question, I am kind of short of time else I would try to figure it out myself, This seems to be a complex program for a beginner like me, hope you understand. Thank you again for your time.

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  • Finding Common Phrases in SQL Server TEXT Column

    - by regex
    Short Desc: I'm curious to see if I can use SQL Analysis services or some other SQL Server service to mine some data for me that will show commonalities between SQL TEXT fields in a dataset. Long Desc I am looking at a subset of data that consists of about 10,000 rows of TEXT blobs which are used as a notes column in a issue tracking (ticketing) software. I would like to use something out of the box (without having to build something) that might be able to parse through all of the rows and find commonly used byte sequences in the "Notes" column. In other words, I want to find commonly used phrases (two to three word phrases, so 9 - 20 character sections of the TEXT blob). This will help me better determine if associate's notes contain similar phrases (troubleshooting techniques) that we could standardize in our troubleshooting process flow. Closing Note I'd really rather not build an application to do this as my method will probably not be the most efficient way to do it. Hopefully all this makes sense. Please let me know in the comments if anything needs clarification.

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  • jQuery image preload/cache halting browser

    - by Nathan Loding
    In short, I have a very large photo gallery and I'm trying to cache as many of the thumbnail images as I can when the first page loads. There could be 1000+ thumbnails. First question -- is it stupid to try to preload/cache that many? Second question -- when the preload() function fires, the entire browser stops responding for a minute to two. At which time the callback fires, so the preload is complete. Is there a way to accomplish "smart preloading" that doesn't impede on the user experience/speed when attempting to load this many objects? The $.preLoadImages function is take from here: http://binarykitten.me.uk/dev/jq-plugins/107-jquery-image-preloader-plus-callbacks.html Here's how I'm implementing it: $(document).ready(function() { setTimeout("preload()", 5000); }); function preload() { var images = ['image1.jpg', ... 'image1000.jpg']; $.preLoadImages(images, function() { alert('done'); }); } 1000 images is a lot. Am I asking too much?

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  • How to implement Excel Solver functionality in C#?

    - by Vic
    Hi, I have an application in C#, I need to do some optimization calculations, like Excel Solver Add-in does, one option is certainly to write my own solver implementation, but I'm kind of short of time, so I'm looking into libraries that already exist that can help me with this. I've been trying the Microsoft Solver Foundation, which seems pretty neat and cool, the problem is that it doesn't seem to work with the kind of calculations that I need to do. At the end of this question I'm adding the information about the calculations I need to perform and optimize. So basically my question is if any of you know of any other library that I can use for this purpose, or any tutorial that can help to do my own solver, or any idea that gives me a lead to solve this issue. Thanks. Additional Info: This is the data I need to calculate: I have 7 variables, lets call them var1, var2,...,var7 The constraints for these variables are: All of them need to be 0 <= varn <= 0.5 (where n is the number of the variable) The sum of all the variables should be equal to 1 The objective is to maximize the target formula, which in Excel looks like this: (MMULT(TRANSPOSE(L26:L32),M14:M20)) / (SQRT(MMULT(MMULT(TRANSPOSE(L26:L32),M4:S10),L26:L32))) The range that you see in this formula, L26:L32, is actually the range with the variables from above, var1, var2,..., varn. M14:M20 and M4:S10 are ranges with data that I get from different sources, there are more likely decimal values. As I said before, I was using Microsoft Solver Foundation, I modeled pretty much everything with it, I created functions that handle the operations of the target formula, but when I tried to solve the model it always fail, I think it is because of the complexity of the operations. In any case, I just wanted to show these data so you can have an idea about the kind of calculations that I need to implement.

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  • Instruments (Leaks) and NSDateFormatter

    - by Cal
    When I run my iPhone app with Instruments Leaks and parse a bunch of NSDates using NSDateFormatter my memory goes up about 1mb and stays even though these NSDates should be dealloc'd after the parsing (I just discard them if they aren't new). I thought the malloc (in my heaviest stack trace below) could become part of the NSDate but I also thought it could be memory that only used during some intermediate step in parsing. Does anyone know which one it is or how to find out? Also, is there a way to put a breakpoint on NSDate dealloc to see if that memory is really being reclaimed? Here's what my date formatter looks like for parsing these dates: df = [[NSDateFormatter alloc] init]; [df setDateFormat:@"EEE, d MMM yyyy H:m:s z"]; Here's the Heaviest Stack trace when the memory bumps up and stays there: 0 libSystem.B.dylib 208.80 Kb malloc 1 libicucore.A.dylib 868.19 Kb icu::ZoneMeta::getSingleCountry(icu::UnicodeString const&, icu::UnicodeString&) 2 libicucore.A.dylib 868.66 Kb icu::ZoneMeta::getSingleCountry(icu::UnicodeString const&, icu::UnicodeString&) 3 libicucore.A.dylib 868.67 Kb icu::ZoneMeta::getSingleCountry(icu::UnicodeString const&, icu::UnicodeString&) 4 libicucore.A.dylib 868.67 Kb icu::DateFormatSymbols::initZoneStringFormat() 5 libicucore.A.dylib 868.67 Kb icu::DateFormatSymbols::getZoneStringFormat() const 6 libicucore.A.dylib 868.67 Kb icu::SimpleDateFormat::subParse(icu::UnicodeString const&, int&, unsigned short, int, signed char, signed char, signed char*, icu::Calendar&) const 7 libicucore.A.dylib 868.67 Kb icu::SimpleDateFormat::parse(icu::UnicodeString const&, icu::Calendar&, icu::ParsePosition&) const 8 libicucore.A.dylib 868.67 Kb icu::DateFormat::parse(icu::UnicodeString const&, icu::ParsePosition&) const 9 libicucore.A.dylib 868.67 Kb udat_parse 10 CoreFoundation 868.67 Kb CFDateFormatterGetAbsoluteTimeFromString 11 CoreFoundation 868.67 Kb CFDateFormatterCreateDateFromString 12 Foundation 868.67 Kb -[NSDateFormatter getObjectValue:forString:range:error:] 13 Foundation 868.75 Kb -[NSDateFormatter getObjectValue:forString:errorDescription:] 14 Foundation 868.75 Kb -[NSDateFormatter dateFromString:] Thanks!

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  • Uncatchable AccesViolationException

    - by Roy
    Hi all, I'm getting close to desperate.. I am developing a field service application for Windows Mobile 6.1 using C# and quite some p/Invoking. (I think I'm referencing about 50 native functions) On normal circumstances this goes without any problem, but when i start stressing the GC i'm getting a nasty 0xC0000005 error witch seems uncatchable. In my test i'm rapidly closing and opening a dialog form (the form did make use of native functions, but for testing i commented these out) and after a while the Windows Mobile error reporter comes around to tell me that there was an fatal error in my application. My code uses a try-catch around the Application.Run(masterForm); and hooks into the CurrentDomain.UnhandledException event, but the application still crashes. Even when i attach the debugger, visual studio just tells me "The remote connection to the device has been lost" when the exception occurs.. Since I didn't succeed to catch the exception in the managed environment, I tried to make sense out of the Error Reporter log file. But this doesn't make any sense, the only consistent this about the error is the application where it occurs in. The thread where the application occurs in is unknown to me, the module where the error occurs differs from time to time (I've seen my application.exe, WS2.dll, netcfagl3_5.dll and mscoree3_5.dll), even the error code is not always the same. (most of the time it's 0xC0000005, but i've also seen an 0X80000002 error, which is a warning accounting the first byte?) I tried debugging through bugtrap, but strangely enough this crashes with the same error code (0xC0000005). I tried to open the kdmp file with visual studio, but i can't seem to make any sense out of this because it only shows me disassembler code when i step into the error (unless i have the right .pbb files, which i don't). Same goes for WinDbg. To make a long story short: I frankly don't have a single clue where to look for this error, and I'm hoping some bright soul on stackoverflow does. I'm happy to provide some code but at this moment I don't know which piece to provide.. Any help is greatly appreciated!

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  • PCRE/PHP regex not matching last "item"

    - by superbarney
    Here's a regex that I've cobbled up: /(.*={76}\s)?\s*(.*?)\s\-\-\s(\d{2}\/\d{2}\-\d{2}\s\d{2}:\d{2})\s\s(.*?)\s(http:\/\/service.*?)\s(\-{76})/is and here's the text I will be parsing: http://p.linode.com/7015 and here's the replacement for the matched text: <item>\n\t<title>$2</title>\n\t<pubDate>$pubDate</pubDate>\n\t<description>$4</description>\n\t<link>$5</link>\n</item>\n\n I have almost come up with a regex needed to parse a block of text into RSS 2.0 XML markup. I've tested it with RegExr and RegexBuddy and it works perfectly except for the last "item" where there is no line breaks after the link (Line 269). In short, the problem is the "iProperty" article in the text is not matched. Any regex gurus willing to help me troubleshoot what's wrong? I've tried /(.*={76}\s)?\s*(.*?)\s\-\-\s(\d{2}\/\d{2}\-\d{2}\s\d{2}:\d{2})\s\s(.*?)\s(http:\/\/service.*?)\s*(\-{76})/is Here's the output that I get: http://p.linode.com/7016 but that didn't work as I expected (i.e. a newline would be optional). Thanks!

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  • Why is Swing Parser's handleText not handling nested tags?

    - by Jim P
    I need to transform some HTML text that has nested tags to decorate 'matches' with a css attribute to highlight it (like firefox search). I can't just do a simple replace (think if user searched for "img" for example), so I'm trying to just do the replace within the body text (not on tag attributes). I have a pretty straightforward HTML parser that I think should do this: final Pattern pat = Pattern.compile(srch, Pattern.CASE_INSENSITIVE); Matcher m = pat.matcher(output); if (m.find()) { final StringBuffer ret = new StringBuffer(output.length()+100); lastPos=0; try { new ParserDelegator().parse(new StringReader(output.toString()), new HTMLEditorKit.ParserCallback () { public void handleText(char[] data, int pos) { ret.append(output.subSequence(lastPos, pos)); Matcher m = pat.matcher(new String(data)); ret.append(m.replaceAll("<span class=\"search\">$0</span>")); lastPos=pos+data.length; } }, false); ret.append(output.subSequence(lastPos, output.length())); return ret; } catch (Exception e) { return output; } } return output; My problem is, when I debug this, the handleText is getting called with text that includes tags! It's like it's only going one level deep. Anyone know why? Is there some simple thing I need to do to HTMLParser (haven't used it much) to enable 'proper' behavior of nested tags? PS - I figured it out myself - see answer below. Short answer is, it works fine if you pass it HTML, not pre-escaped HTML. Doh! Hope this helps someone else. <span>example with <a href="#">nested</a> <p>more nesting</p> </span> <!-- all this gets thrown together -->

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  • Can't contravariance be solved with interfaces?

    - by Sir Psycho
    Hi, I'm at the point where I'm starting to grasp contravariance, although I'm trying to work out what the advantage is when an interface can be used instead. Obviously I'm missing something. Here is the c#4 example class Dog : Animal { public Dog(string name) : base(name) { } } class Animal { string _name; public Animal(string name) { _name = name; } public void Walk() { Console.WriteLine(_name + " is walking"); } } Action<Animal> MakeItMove = (ani) => { ani.Walk(); }; Action<Dog> MakeItWalk = MakeItMove; MakeItWalk(new Dog("Sandy")); Same example which works in earlier versions on c# class Dog : Animal { public Dog(string name) : base(name) { } } class Animal : IAnimal { string _name; public Animal(string name) { _name = name; } public void Walk() { Console.WriteLine(_name + " is walking"); } } interface IAnimal { void Walk(); } Action<IAnimal> MakeItMove = (ani) => { ani.Walk(); }; Action<IAnimal> MakeItWalk = MakeItMove; MakeItWalk(new Dog("Sandy")); These may not be the best examples, but I still can't seem to 'get it'. Is the in keywork defined on the action delegate simply a short hand syntax way like lamda is to delegates?

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  • matlab precision determinant problem

    - by ldigas
    I have the following program format compact; format short g; clear; clc; L = 140; J = 77; Jm = 10540; G = 0.8*10^8; d = L/3; for i=1:500000 omegan=1.+0.0001*i; a(1,1) = ((omegan^2)*(Jm/(G*J))*d^2)-2; a(1,2) = 2; a(1,3) = 0; a(1,4) = 0; a(2,1) = 1; a(2,2) = ((omegan^2)*(Jm/(G*J))*d^2)-2; a(2,3) = 1; a(2,4) = 0; a(3,1) = 0; a(3,2) = 1; a(3,3) = ((omegan^2)*(Jm/(G*J))*d^2)-2; a(3,4) = 1; a(4,1) = 0; a(4,2) = 0; a(4,3) = 2; a(4,4) = ((omegan^2)*(Jm/(G*J))*d^2)-2; if(abs(det(a))<1E-10) sprintf('omegan= %8.3f det= %8.3f',omegan,det(a)) end end Analytical solution of the above system, and the same program written in fortran gives out values of omegan equal to 16.3818 and 32.7636 (fortran values; analytical differ a little, but they're there somewhere). So, now I'm wondering ... where am I going wrong with this ? Why is matlab not giving the expected results ? (this is probably something terribly simple, but it's giving me headaches)

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  • CSS sliding-door buttons center alignment

    - by rochal
    Hi guys, I need help to align CSS buttons. I tried many different variations and I just cannot center my button the way I want. Firstly, have a look at this url: http://www.front-end-developer.net/cssbuttons/example.htm I'm using 2 images to form a button (this could be done on 1 image, but in this case we've got two). Everything works as expected as long as we apply float:left or float:right to the parent div element, to 'limit' width of the div and close it as soon as the content of the div ends. You can remove float:left from the button to see what I mean. But what about center positioned buttons? I cannot add float:left/right because I want align it in the middle. In theory, I could set { width:XXpx; margin:0 auto; } And I will get what you can see on this picture: But I don't know the length of the text inside. Having different translations my button can be very short, or 5 times that long. I also tried to use <span> instead of <div>, but unfortunately nested inline elements don't respect their padding correctly... And yes, I must use <a> inside, so buttons can be accessed by web crawlers. I'm really stuck on this one.

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  • SQL deadlock on delete then bulk insert

    - by StarLite
    I have an issue with a deadlock in SQL Server that I haven't been able to resolve. Basically I have a large number of concurrent connections (from many machines) that are executing transactions where they first delete a range of entries and then re-insert entries within the same range with a bulk insert. Essentially, the transaction looks like this BEGIN TRANSACTION T1 DELETE FROM [TableName] WITH( XLOCK HOLDLOCK ) WHERE [Id]=@Id AND [SubId]=@SubId INSERT BULK [TableName] ( [Id] Int , [SubId] Int , [Text] VarChar(max) COLLATE SQL_Latin1_General_CP1_CI_AS ) WITH(CHECK_CONSTRAINTS, FIRE_TRIGGERS) COMMIT TRANSACTION T1 The bulk insert only inserts items matching the Id and SubId of the deletion in the same transaction. Furthermore, these Id and SubId entries should never overlap. When I have enough concurrent transaction of this form, I start to see a significant number of deadlocks between these statements. I added the locking hints XLOCK HOLDLOCK to attempt to deal with the issue, but they don't seem to be helpling. The canonical deadlock graph for this error shows: Connection 1: Holds RangeX-X on PK_TableName Holds IX Page lock on the table Requesting X Page lock on the table Connection 2: Holds IX Page lock on the table Requests RangeX-X lock on the table What do I need to do in order to ensure that these deadlocks don't occur. I have been doing some reading on the RangeX-X locks and I'm not sure I fully understand what is going on with these. Do I have any options short of locking the entire table here?

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  • NSTextView's adjustScroll method

    - by Mike
    I'm trying to implement typewriter scrolling in my Cocoa text editor, keeping the insertion point centered vertically in its scrollview. Toward this end, I have subclassed NSClipView to provide a scrollToPointWithoutConstraint method, which scrolls the document to a specified point without calling constrainScrollPoint. This is necessary because for short documents the insertion point can't be centered unless we scroll beyond the document's bounds. This seems reasonably straightforward so far and does what I want. The problem comes in when I try to scroll using the scroll bars. If I'm scrolled to the end of the document, such that part of the scroll view contains an area outside the document's bounds, trying to scroll up by a small increment causes the scroll view to jump, immediately clamping to the document's actual bounds. I gather that I might need to subclass NSTextView and override the adjustScroll method; this is where my actual question begins. The proposedVisibleRect that is passed to adjustScroll already has its dimensions adjusted so that they lie within the document's actual bounds. Is there a way that I can change the value of proposedVisibleRect before adjustScroll is called? Alternatively, am I going about this entirely wrong? Any suggestions would be greatly appreciated at this point.

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  • decimal.TryParse() drops leading "1"

    - by Martin Harris
    Short and sweet version: On one machine out of around a hundred test machines decimal.TryParse() is converting "1.01" to 0.01 Okay, this is going to sound crazy but bare with me... We have a client applications that communicates with a webservice through JSON, and that service returns a decimal value as a string so we store it as a string in our model object: [DataMember(Name = "value")] public string Value { get; set; } When we display that value on screen it is formatted to a specific number of decimal places. So the process we use is string - decimal then decimal - string. The application is currently undergoing final testing and is running on more than 100 machines, where this all works fine. However on one machine if the decimal value has a leading '1' then it is replaced by a zero. I added simple logging to the code so it looks like this: Log("Original string value: {0}", value); decimal val; if (decimal.TryParse(value, out val)) { Log("Parsed decimal value: {0}", val); string output = val.ToString(format, CultureInfo.InvariantCulture.NumberFormat); Log("Formatted string value: {0}", output); return output; } On my machine - any every other client machine - the logfile output is: Original string value: 1.010000 Parsed decimal value: 1.010000 Formatted string value: 1.01 On the defective machine the output is: Original string value: 1.010000 Parsed decimal value: 0.010000 Formatted string value: 0.01 So it would appear that the decimal.TryParse method is at fault. Things we've tried: Uninstalling and reinstalling the client application Uninstalling and reinstalling .net 3.5 sp1 Comparing the defective machine's regional settings for numbers (using English (United Kingdom)) to those of a working machine - no differences. Has anyone seen anything like this or has any suggestions? I'm quickly running out of ideas... While I was typing this some more info came in: Passing a string value of "10000" to Convert.ToInt32() returns 0, so that also seems to drop the leading 1.

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  • Synchronizing ASP.NET MVC action methods with ReaderWriterLockSlim

    - by James D
    Any obvious issues/problems/gotchas with synchronizing access (in an ASP.NET MVC blogging engine) to a shared object model (NHibernate, but it could be anything) at the Controller/Action level via ReaderWriterLockSlim? (Assume the object model is very large and expensive to build per-request, so we need to share it among requests.) Here's how a typical "Read Post" action would look. Enter the read lock, do some work, exit the read lock. public ActionResult ReadPost(int id) { // ReaderWriterLockSlim allows multiple concurrent writes; this method // only blocks in the unlikely event that some other client is currently // writing to the model, which would only happen if a comment were being // submitted or a new post were being saved. _lock.EnterReadLock(); try { // Access the model, fetch the post with specificied id // Pseudocode, etc. Post p = TheObjectModel.GetPostByID(id); ActionResult ar = View(p); return ar; } finally { // Under all code paths, we must release the read lock _lock.ExitReadLock(); } } Meanwhile, if a user submits a comment or an author authors a new post, they're going to need write access to the model, which is done roughly like so: [AcceptVerbs(HttpVerbs.Post)] public ActionResult SaveComment(/* some posted data */) { // try/finally omitted for brevity _lock.EnterWriteLock(); // Save the comment to the DB, update the model to include the comment, etc. _lock.ExitWriteLock(); } Of course, this could also be done by tagging those action methods with some sort of "synchronized" attribute... but however you do it, my question is is this a bad idea? ps. ReaderWriterLockSlim is optimized for multiple concurrent reads, and only blocks if the write lock is held. Since writes are so infrequent (1000s or 10,000s or 100,000s of reads for every 1 write), and since they're of such a short duration, the effect is that the model is synchronized , and almost nobody ever locks, and if they do, it's not for very long.

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  • Lightweight spinlocks built from GCC atomic operations?

    - by Thomas
    I'd like to minimize synchronization and write lock-free code when possible in a project of mine. When absolutely necessary I'd love to substitute light-weight spinlocks built from atomic operations for pthread and win32 mutex locks. My understanding is that these are system calls underneath and could cause a context switch (which may be unnecessary for very quick critical sections where simply spinning a few times would be preferable). The atomic operations I'm referring to are well documented here: http://gcc.gnu.org/onlinedocs/gcc-4.4.1/gcc/Atomic-Builtins.html Here is an example to illustrate what I'm talking about. Imagine a RB-tree with multiple readers and writers possible. RBTree::exists() is read-only and thread safe, RBTree::insert() would require exclusive access by a single writer (and no readers) to be safe. Some code: class IntSetTest { private: unsigned short lock; RBTree<int>* myset; public: // ... void add_number(int n) { // Aquire once locked==false (atomic) while (__sync_bool_compare_and_swap(&lock, 0, 0xffff) == false); // Perform a thread-unsafe operation on the set myset->insert(n); // Unlock (atomic) __sync_bool_compare_and_swap(&lock, 0xffff, 0); } bool check_number(int n) { // Increment once the lock is below 0xffff u16 savedlock = lock; while (savedlock == 0xffff || __sync_bool_compare_and_swap(&lock, savedlock, savedlock+1) == false) savedlock = lock; // Perform read-only operation bool exists = tree->exists(n); // Decrement savedlock = lock; while (__sync_bool_compare_and_swap(&lock, savedlock, savedlock-1) == false) savedlock = lock; return exists; } }; (lets assume it need not be exception-safe) Is this code indeed thread-safe? Are there any pros/cons to this idea? Any advice? Is the use of spinlocks like this a bad idea if the threads are not truly concurrent? Thanks in advance. ;)

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  • Interactive Web Collaboration Platform

    - by user1477586
    I am currently unsatisfied with most, if not all, web-based collaboration tools I've ever used. Examples of what I'm considering a "web-based collaboration tool" are TWiki, WebEx, etc. What I have in mind of developing is to develop my own. The target "market" is for software/hardware developers who will likely be working on separate projects linked by a common goal. Example: You work at a company who is designing a brand new printer. So, one man is working on the ink cartridge, another on the paper feed, one on the circuitry of the printer and one more is working on the drivers. What I would like to make (unless it already exists) is a website that, upon loading, presents the user with a web that has each project within it's own bubble, graphically. These bubbles would all be linked to the central bubble of "[Company Name]". Upon selecting an individual bubble the browser would focus and zoom in on that project bubble and expand more information (in bullets or with more affiliated bubbles) about subprojects, progress, setbacks, etc. Then, at a terminal "node" (i.e. a bubble with no sub-bubbles) a selection would then load a page with information relevant to that node. That's a lot of monologue. In short, I want to know how I might approach this. My background is with algorithmic use of Python and C++. I've never done interactive web design like this; though, I have gone through the W3C tutorials on HTML4/5. I'm willing to learn a new language I'm just wondering which language/set of languages seem(s) most appropriate for this project. Thanks, world, for imparting your knowledge to me. An example of what the start page might look like is:

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  • How do you jump to a particular row in a DataGridView by typing (a la Windows Explorer details view)

    - by russcollier
    I have a .NET Winforms app in C# with a DataGridView that's read-only and populated with some number of rows. I'd like to have functionality similar to Windows Explorer's (and many other applications) details view for example. I'd like the DataGridView to behave such that when it has focus if you start typing, the current row selection will jump to the row where the (string) value of cell 0 (i.e. the first column in the row) starts with the characters you typed in. For example, if I have a DataGridView with 1 column and the following rows: Bob Jane Jason John Leroy Sam If the DataGridView has focus and I hit the 'b' key on my keyboard, the selected row is now "Bob". If I quickly type in the keys 'ja', the selected row is Jane. If I quickly type in the letters 'jas', the selected row is Jane. If I hit the 'z' key, nothing is selected (since nothing starts with Z). Likewise if Jane is currently selected and I keep typing the letter 'j', the selection will cycle through to Jason, then John, then back to Jane, each time I hit the 'j' key. I've been doing some Googling (and "stackoverflowing" :-)) for awhile and cannot find any examples of this type of functionality. I have a rough idea in my head to do this via some sort of short lived timer thread, collecting the keystrokes on KeyPress events for the DataGridView, and selecting rows based on those collected keystrokes matching a Cells[0].Value.StartsWith() type of condition. But it seems like there has to be an easier way that I'm just not seeing. Any ideas would be much appreciated. Thanks!

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  • What's a good way of building up a String where you specific start and end locations?

    - by Michael Campbell
    (java 1.5) I have a need to build up a String, in pieces. I'm given a set of (sub)strings, each with a start and end point of where they belong in the final string. Was wondering if there were some canonical way of doing this. This isn't homework, and I can use any licensable OSS, such as jakarta commons-lang StringUtils etc. My company has a solution using a CharBuffer, and I'm content to leave it as is (and add some unit tests, of which there are none (?!)) but the code is fairly hideous and I would like something easier to read. As I said this isn't homework, and I don't need a complete solution, just some pointers to libraries or java classes that might give me some insight. The String.Format didn't seem QUITE right... I would have to honor inputs too long and too short, etc. Substrings would be overlaid in the order they appear (in case of overlap). As an example of input, I might have something like: String:start:end FO:0:3 (string shorter than field) BAR:4:5 (String larger than field) BLEH:5:9 (String overlays previous field) I'd want to end up with FO BBLEH 01234567890

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  • Just introducing myself to TMPing, and came across a quirk

    - by Justen
    I was just trying to learn the syntax of the beginner things, and how it worked when I was making this short bit of code. The code below works in adding numbers 1 to 499, but if I add 1 to 500, the compiler bugs out giving me: fatal error C1001: An internal error has occurred in the compiler. And I was just wondering why that is. Is there some limit to how much code the compiler can generate or something and it just happened to be a nice round number of 500 for me? #include <iostream> using namespace std; template < int b > struct loop { enum { sum = loop< b - 1 >::sum + b }; }; template <> struct loop< 0 > { enum { sum = 0 }; }; int main() { cout << "Adding the numbers from 1 to 499 = " << loop< 499 >::sum << endl; return 0; }

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  • RegAsm for Class Library Used in VB6 Application

    - by michael.lukatchik
    To be short and to the point, I've built a C# class library that is both COM-Visible and Registered for COM Interop. I've compiled the library, which resulted in the generation of .dll and .tlb files. I have another machine that's running a VB6 application. So, I copied the .dll and .tlb files over to C:/Windows/system32 folder on the machine. I then registered those files using the following: C:\Windows\Microsoft.NET\Framework\v2.0.50727\RegAsm C:\Windows\system32\TestClass.dll /tlb:TestClass.tlb After the files were registered successfully, I added a project reference to the Test.tlb file from inside my VB6 app, then I tried to invoke a method in my new referenced class like so: Dim myObject As TestNamespace.TestClass Set myObject = New TestNamespace.TestClass MsgBox (myObject.TestMethod()) It doesn't work, and I receive a -2147024894 Automation Error. I've read that I shouldn't install the dll into a private folder like system32. I should either be registering in the GAC or I should be registering in another location using the "/codebase" option: C:\Windows\Microsoft.NET\Framework\v2.0.50727\RegAsm C:\TestClass.dll /tlb:TestClass.tlb /codebase Is there any reason I shouldn't be using system32? Past devs that have worked on this project have placed assembly files used by this VB6 project into system32 and there haven't seemed to be any issues. When I register my dll in the system32 location, I get the Automation Error. When I register my dll in another location (i.e. C:/), the method call into my class library from VB6 works as expected. What gives? I should mention that we will NOT be using the GAC to register any DLL's. That's just the way it is. Any help is appreciated. Mike

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  • Selenium RC: how to capture/handle error?

    - by KenBurnsFan1
    Hi, My test uses Selenium to loop through a CSV list of URLs via an HTTP proxy (working script below). As I watch the script run I can see about 10% of the calls produce "Proxy error: 502" ("Bad_Gateway"); however, the errors are not captured by my catch-all "except Exception" clause -- ie: instead of writing 'error' in the appropriate row of the "output.csv", they get passed to the else clause and produce a short piece of html that starts: "Proxy error: 502 Read from server failed: Unknown error." Also, if I collect all the URLs which returned 502s and re-run the script, they all pass, which leads me to believe that this is a sporadic network path issue. Question: Can the script be made to recognize the the 502 errors, sleep a minute, and then retry the URL instead of moving on to the next URL in the list? The only alternative that I can think of is to apply re.search("Proxy error: 502") after "get_html_source" as a way to catch the bad calls. Then, if the RE matches, put the script to sleep for a minute and then retry 'sel.open(row[0]' on the URL which produced the 502. Any advice would be much appreciated. Thanks! #python 2.6 from selenium import selenium import unittest, time, re, csv, logging class Untitled(unittest.TestCase): def setUp(self): self.verificationErrors = [] self.selenium = selenium("localhost", 4444, "*firefox", "http://baseDomain.com") self.selenium.start() self.selenium.set_timeout("60000") def test_untitled(self): sel = self.selenium spamReader = csv.reader(open('ListOfSubDomains.csv', 'rb')) for row in spamReader: try: sel.open(row[0]) except Exception: ofile = open('output.csv', 'ab') ofile.write("error" + '\n') ofile.close() else: time.sleep(5) html = sel.get_html_source() ofile = open('output.csv', 'ab') ofile.write(html.encode('utf-8') + '\n') ofile.close() def tearDown(self): self.selenium.stop() self.assertEqual([], self.verificationErrors) if __name__ == "__main__": unittest.main()

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  • PHP jQuery Long Polling Chat Application

    - by Tejas Jadhav
    I've made a simple PHP jQuery Chat Application with Short Polling (AJAX Refresh). Like, every 2 - 3 seconds it asks for new messages. But, I read that Long Polling is a better approach for Chat applications. So, I went through some Long Polling scripts. I made like this: Javascript: $("#submit").click(function(){ $.ajax({ url: 'chat-handler.php', dataType: 'json', data: {action : 'read', message : 'message'} }); }); var getNewMessage = function() { $.ajax({ url: 'chat-handler.php', dataType: 'json', data: {action : 'read', message : 'message'}, function(data){ alert(data); } }); getNewMessage(); } $(document).ready(getNewMessage); PHP <?php $time = time(); while ((time() - $time) < 25) { $data = $db->getNewMessage (); if (!empty ($data)) { echo json_encode ($data); break; } usleep(1000000); // 1 Second } ?> The problem is, once getNewMessage() starts, it executes unless it gets some response (from chat-handler.php). It executes recursively. But if someone wants to send a message in between, then actually that function ($("#submit").click()) never executes as getNewMessage() is still executing. So is there any workaround?

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