Search Results

Search found 13867 results on 555 pages for 'avoid learning'.

Page 488/555 | < Previous Page | 484 485 486 487 488 489 490 491 492 493 494 495  | Next Page >

• Efficient (basic) regular expression implementation for streaming data

  - by Brendan Dolan-Gavitt

  I'm looking for an implementation of regular expression matching that operates on a stream of data -- i.e., it has an API that allows a user to pass in one character at a time and report when a match is found on the stream of characters seen so far. Only very basic (classic) regular expressions are needed, so a DFA/NFA based implementation seems like it would be well-suited to the problem. Based on the fact that it's possible to do regular expression matching using a DFA/NFA in a single linear sweep, it seems like a streaming implementation should be possible. Requirements: The library should try to wait until the full string has been read before performing the match. The data I have really is streaming; there is no way to know how much data will arrive, it's not possible to seek forward or backward. Implementing specific stream matching for a couple special cases is not an option, as I don't know in advance what patterns a user might want to look for. For the curious, my use case is the following: I have a system which intercepts memory writes inside a full system emulator, and I would like to have a way to identify memory writes that match a regular expression (e.g., one could use this to find the point in the system where a URL is written to memory). I have found (links de-linkified because I don't have enough reputation): stackoverflow.com/questions/1962220/apply-a-regex-on-stream stackoverflow.com/questions/716927/applying-a-regular-expression-to-a-java-i-o-stream www.codeguru.com/csharp/csharp/cs_data/searching/article.php/c14689/Building-a-Regular-Expression-Stream-Search-with-the-NET-Framework.htm But all of these attempt to convert the stream to a string first and then use a stock regular expression library. Another thought I had was to modify the RE2 library, but according to the author it is architected around the assumption that the entire string is in memory at the same time. If nothing's available, then I can start down the unhappy path of reinventing this wheel to fit my own needs, but I'd really rather not if I can avoid it. Any help would be greatly appreciated!

  Read the article

• Generic that takes only numeric types (int double etc)?

  - by brandon

  In a program I'm working on, I need to write a function to take any numeric type (int, short, long etc) and shove it in to a byte array at a specific offset. There exists a Bitconverter.GetBytes() method that takes the numeric type and returns it as a byte array, and this method only takes numeric types. So far I have: private void AddToByteArray<T>(byte[] destination, int offset, T toAdd) where T : struct { Buffer.BlockCopy(BitConverter.GetBytes(toAdd), 0, destination, offset, sizeof(toAdd)); } So basically my goal is that, for example, a call to AddToByteArray(array, 3, (short)10) would take 10 and store it in the 4th slot of array. The explicit cast exists because I know exactly how many bytes I want it to take up. There are cases where I would want a number that is small enough to be a short to really take up 4 bytes. On the flip side, there are times when I want an int to be crunched down to just a single byte. I'm doing this to create a custom network packet, if that makes any ideas pop in to your heads. If the where clause of a generic supported something like "where T : int || long || etc" I would be ok. (And no need to explain why they don't support that, the reason is fairly obvious) Any help would be greatly appreciated! Edit: I realize that I could just do a bunch of overloads, one for each type I want to support... but I'm asking this question because I want to avoid precisely that :)

  Read the article

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

  - by Mark Zeren

  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.

  Read the article

• Web page for IPhone - Large fonts instead of scrolling?

  - by chris_l

  I'm planning the layout of my web page, which should also be usable on the IPhone. I don't really have much experience with the IPhone yet - I just installed the IPhone Simulator on my Mac. The page's contents are flexible, so I think it would be better to use this flexibility to avoid that the user has to scroll around the entire page. Especially I have A header and a sidebar that will be used all the time to perform several actions. A main content area with a number of elements (e.g. images). The UI would stay usable pretty well, if the number of elements shown at one time is reduced for a small screen (e.g. by JavaScript). It would also be okay to make the main content area scrollable (as opposed to the entire page). The problem: If I simply display the page on the IPhone, it uses an extremely small font size, so that users must zoom in first, and then scroll around - so that they can't see the header and sidebar all the time. What's the best way to deal with this situation? Just leave it this way (very small fonts), because users expect that behaviour on the IPhone? Increase the font size (by specifying it in em or px or with xx-large, or what would be the best way?), if I detect - somehow - that it's being displayed on the IPhone. Or is there some way to restrict the viewport size to the screen size, and make it zoom in automatically? I think that would be the easiest solution in my case. Or ...?

  Read the article

• Robotlegs: Warning: Injector already has a rule for type

  - by MikeW

  I have a bunch of warning messages like this appear when using Robotlegs/Signals. Everytime this command class executes, which is every 2-3 seconds ..this message displays below If you have overwritten this mapping intentionally you can use "injector.unmap()" prior to your replacement mapping in order to avoid seeing this message. Warning: Injector already has a rule for type "mx.messaging.messages::IMessage", named "". The command functions fine otherwise but I think I'm doing something wrong anyhow. public class MessageReceivedCommand extends SignalCommand { [Inject] public var message:IMessage; ...etc.. do something with message.. } the application context doesnt map IMessage to this command, as I only see an option to mapSignalClass , besides the payload is received fine. Wonder if anyone knows how I might either fix or suppress this message. I've tried calling this as the warning suggests injector.unmap(IMessage, "") but I receive an error - no mapping found for ::IMessage named "". Thanks Edit: A bit more info about the error Here is the signal that I dispatch to the command public class GameMessageSignal extends Signal { public function GameMessageSignal() { super(IMessage); } } which is dispatched from a IPushDataService class gameMessage.dispatch(message.message); and the implementation is wired up in the app context via injector.mapClass(IPushDataService, PushDataService); along with the signal signalCommandMap.mapSignalClass(GameMessageSignal, MessageReceivedCommand); Edit #2: Probably good to point out also I inject an instance of GameMessageSignal into IPushDataService public class PushDataService extends BaseDataService implements IPushDataService { [Inject] public var gameMessage:GameMessageSignal; //then private function processMessage(message:MessageEvent):void { gameMessage.dispatch(message.message); } } Edit:3 The mappings i set up in the SignalContext: injector.mapSingleton(IPushDataService); injector.mapClass(IPushDataService, PushDataService);

  Read the article

• typedef struct, circular dependency, forward definitions

  - by BlueChip

  The problem I have is a circular dependency issue in C header files ...Having looked around I suspect the solution will have something to do with Forward Definitions, but although there are many similar problems listed, none seem to offer the information I require to resolve this one... I have the following 5 source files: // fwd1.h #ifndef __FWD1_H #define __FWD1_H #include "fwd2.h" typedef struct Fwd1 { Fwd2 *f; } Fwd1; void fwd1 (Fwd1 *f1, Fwd2 *f2) ; #endif // __FWD1_H . // fwd1.c #include "fwd1.h" #include "fwd2.h" void fwd1 (Fwd1 *f1, Fwd2 *f2) { return; } . // fwd2.h #ifndef __FWD2_H #define __FWD2_H #include "fwd1.h" typedef struct Fwd2 { Fwd1 *f; } Fwd2; void fwd2 (Fwd1 *f1, Fwd2 *f2) ; #endif // __FWD2_H . // fwd2.c #include "fwd1.h" #include "fwd2.h" void fwd2 (Fwd1 *f1, Fwd2 *f2) { return; } . // fwdMain.c #include "fwd1.h" #include "fwd2.h" int main (int argc, char** argv, char** env) { Fwd1 *f1 = (Fwd1*)0; Fwd2 *f2 = (Fwd2*)0; fwd1(f1, f2); fwd2(f1, f2); return 0; } Which I am compiling with the command: gcc fwdMain.c fwd1.c fwd2.c -o fwd -Wall I have tried several ideas to resolve the compile errors, but have only managed to replace the errors with other errors ...How do I resolve the circular dependency issue with the least changes to my code? ...Ideally, as a matter of coding style, I would like to avoid putting the word "struct" all over my code.

  Read the article

• Freetype2 (error-)return value documentation

  - by Awaki

  In short, I'm looking for documentation that would limit the error situations to check for after a Freetype library function failed, much like the OpenGL and Win32 APIs document the error codes generated by their respective functions. I can't seem to find such documentation though, so I was wondering how to best handle translation of Freetype errors to typed exceptions. Background: I am currently in the process of implementing font-rendering capability (using Freetype) for my GUI framework, which makes strong use of typed exceptions to indicate error situations. However, the Freetype docs seem to completely omit what errors can be expected from what functions. That, if such documentation does indeed not exist, would basically leave me with two options: either guessing which errors make sense for a certain Freetype function (obviously prone to mistakes on my part), or considering every error code for translation into appropriate exceptions (less verbose since I would have to write the translation only once). Performance isn't really critical in the code that calls the Freetype library, so even the latter option would probably be acceptable, but surely there must be some kind of documentation on which library calls may return what Freetype error? Is there any such documentation which I just somehow managed to not find? Should I go the route of generically expecting every error code for translation? Or are there other ways to approach this problem? By the way, I wanted to avoid introducing some kind of generic FreetypeException (containing a description of the Freetype error) since I intended to completely hide what libraries I'm using (not from a legal point-of-view, mind you), but I guess I can be convinced to do this anyway if the consensus is that it would be the best option. I don't think it matters for this question, but I'm writing in C++.

  Read the article

• MD5CryptoServiceProvider ComputeHash Issues between VS 2003 and VS 2008

  - by owensoroke

  I have a database application that generates a MD5 hash and compares the hash value to a value in our DB (SQL 2K). The original application was written in Visual Studio 2003 and a deployed version has been working for years. Recently, some new machines on the .NET framework 3.5 have been having unrelated issues with our runtime. This has forced us to port our code path from Visual Studio 2003 to Visual Studio 2008. Since that time the hash produced by the code is different than the values in the database. The original call to the function posted in code is: RemoveInvalidPasswordCharactersFromHashedPassword(Text_Scrub(GenerateMD5Hash(strPSW))) I am looking for expert guidance as to whether or not the MD5 methods have changed since VS 2K3 (causing this point of failure), or where other possible problems may be originating from. I realize this may not be the best method to hash, but utimately any changes to the MD5 code would force us to change some 300 values in our DB table and would cost us a lot of time. In addition, I am trying to avoid having to redeploy all of the functioning versions of this application. I am more than happy to post other code including the RemoveInvalidPasswordCharactersFromHashedPassword function, or our Text_Scrub if it is necessary to recieve appropriate feedback. Thank you in advance for your input. Public Function GenerateMD5Hash(ByVal strInput As String) As String Dim md5Provider As MD5 ' generate bytes for the input string Dim inputData() As Byte = ASCIIEncoding.ASCII.GetBytes(strInput) ' compute MD5 hash md5Provider = New MD5CryptoServiceProvider Dim hashResult() As Byte = md5Provider.ComputeHash(inputData) Return ASCIIEncoding.ASCII.GetString(hashResult) End Function

  Read the article

• interface variables are final and static by default and methods are public and abstract

  - by sap

  The question is why it's been decided to have variable as final and static and methods as public and abstract by default. Is there any particular reason for making them implicit,variable as final and static and methods as public and abstract. Why they are not allowing static method but allowing static variable? We have interface to have feature of multiple inheritance in Java and to avoid diamond problem. But how it solves diamond problem,since it does not allow static methods. In the following program, both interfaces have method with the same name..but while implementing only one we implement...is this how diamond problem is solved? interface testInt{ int m = 0; void testMethod(); } interface testInt1{ int m = 10; void testMethod(); } public class interfaceCheck implements testInt, testInt1{ public void testMethod(){ System . out . println ( "m is"+ testInt.m ); System . out . println ( "Hi World!" ); } }

  Read the article

• Output columns not in destination table?

  - by lance

  SUMMARY: I need to use an OUTPUT clause on an INSERT statement to return columns which don't exist on the table into which I'm inserting. If I can avoid it, I don't want to add columns to the table to which I'm inserting. DETAILS: My FinishedDocument table has only one column. This is the table into which I'm inserting. FinishedDocument -- DocumentID My Document table has two columns. This is the table from which I need to return data. Document -- DocumentID -- Description The following inserts one row into FinishedDocument. Its OUTPUT clause returns the DocumentID which was inserted. This works, but it doesn't give me the Description of the inserted document. INSERT INTO FinishedDocument OUTPUT INSERTED.DocumentID SELECT DocumentID FROM Document WHERE DocumentID = @DocumentID I need to return from the Document table both the DocumentID and the Description of the matching document from the INSERT. What syntax do I need to pull this off? I'm thinking it's possible only with the one INSERT statement, by tweaking the OUTPUT clause (in a way I clearly don't understand)? Is there a smarter way that doesn't resemble the path I'm going down here? EDIT: SQL Server 2005

  Read the article

• How to do "map chunks", like terraria or minecraft maps?

  - by O'poil

  Due to performance issues, I have to cut my maps into chunks. I manage the maps in this way: listMap[x][y] = new Tile (x,y); I tried in vain to cut this list for several "chunk" to avoid loading all the map because the fps are not very high with large map. And yet, when I update or Draw I do it with a little tile range. Here is how I proceed: foreach (List<Tile> list in listMap) { foreach (Tile leTile in list) { if ((leTile.Position.X < screenWidth + hero.Pos.X) && (leTile.Position.X > hero.Pos.X - tileSize) && (leTile.Position.Y < screenHeight + hero.Pos.Y) && (leTile.Position.Y > hero.Pos.Y - tileSize) ) { leTile.Draw(spriteBatch, gameTime); } } } (and the same thing, for the update method). So I try to learn with games like minecraft or terraria, and any two manages maps much larger than mine, without the slightest drop of fps. And apparently, they load "chunks". What I would like to understand is how to cut my list in Chunk, and how to display depending on the position of my character. I try many things without success. Thank you in advance for putting me on the right track! Ps : Again, sorry for my English :'( Pps : I'm not an experimented developer ;)

  Read the article

• Immutability and shared references - how to reconcile?

  - by davetron5000

  Consider this simplified application domain: Criminal Investigative database Person is anyone involved in an investigation Report is a bit of info that is part of an investigation A Report references a primary Person (the subject of an investigation) A Report has accomplices who are secondarily related (and could certainly be primary in other investigations or reports These classes have ids that are used to store them in a database, since their info can change over time (e.g. we might find new aliases for a person, or add persons of interest to a report) If these are stored in some sort of database and I wish to use immutable objects, there seems to be an issue regarding state and referencing. Supposing that I change some meta-data about a Person. Since my Person objects immutable, I might have some code like: class Person( val id:UUID, val aliases:List[String], val reports:List[Report]) { def addAlias(name:String) = new Person(id,name :: aliases,reports) } So that my Person with a new alias becomes a new object, also immutable. If a Report refers to that person, but the alias was changed elsewhere in the system, my Report now refers to the "old" person, i.e. the person without the new alias. Similarly, I might have: class Report(val id:UUID, val content:String) { /** Adding more info to our report */ def updateContent(newContent:String) = new Report(id,newContent) } Since these objects don't know who refers to them, it's not clear to me how to let all the "referrers" know that there is a new object available representing the most recent state. This could be done by having all objects "refresh" from a central data store and all operations that create new, updated, objects store to the central data store, but this feels like a cheesy reimplementation of the underlying language's referencing. i.e. it would be more clear to just make these "secondary storable objects" mutable. So, if I add an alias to a Person, all referrers see the new value without doing anything. How is this dealt with when we want to avoid mutability, or is this a case where immutability is not helpful?

  Read the article

• Issue with transparent texture on 3D primitive, XNA 4.0

  - by Bevin

  I need to draw a large set of cubes, all with (possibly) unique textures on each side. Some of the textures also have parts of transparency. The cubes that are behind ones with transparent textures should show through the transparent texture. However, it seems that the order in which I draw the cubes decides if the transparency works or not, which is something I want to avoid. Look here: cubeEffect.CurrentTechnique = cubeEffect.Techniques["Textured"]; Block[] cubes = new Block[4]; cubes[0] = new Block(BlockType.leaves, new Vector3(0, 0, 3)); cubes[1] = new Block(BlockType.dirt, new Vector3(0, 1, 3)); cubes[2] = new Block(BlockType.log, new Vector3(0, 0, 4)); cubes[3] = new Block(BlockType.gold, new Vector3(0, 1, 4)); foreach(Block b in cubes) { b.shape.RenderShape(GraphicsDevice, cubeEffect); } This is the code in the Draw method. It produces this result: As you can see, the textures behind the leaf cube are not visible on the other side. When i reverse index 3 and 0 on in the array, I get this: It is clear that the order of drawing is affecting the cubes. I suspect it may have to do with the blend mode, but I have no idea where to start with that.

  Read the article

• Updating a Database from DataBound Controls

  - by Avatar_Squadron

  Hi. I'm currently creating a WinForm in VB.NET bound to an access database. Basically what i have are two forms: one is a search form used to search the database, and the other is a details form. You run a search on the searchForm and it returns a list of Primary Keys and a few other identifying values. You then double click on the entry you want to view, and it loads the details form. The Details form has a collection of databound controls to display the data: mostly text boxes and checkboxs. The way i've set it up is i used the UI to build the form and then set the DataBindings Property of each control to "TblPropertiesBindingSource - " where value name is one of the values in the table (such as PropertyID or HasWoodFloor). Then, when you double click an entry in the searchform, I handle the event by parsing the Primary Key (PropertyID) out of the selected row and then storing this to the details form: Note: Detail is the details form that is opened to display the info Private Sub propView_CellDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles propView.CellDoubleClick Dim detail As frmPropertiesDetail = New frmPropertiesDetail detail.id = propView.Rows(e.RowIndex).Cells(0).Value detail.Show() End Sub Then, upon loading the details form, it set's the filter on the BindSource as such: TblPropertiesBindingSource.Filter() = "PropertyID=" & id This works great so far. All the controls on the details form will display the correct info. The problem is updating changes. Scenario: If i have the user load the details for say, property 10001, it will show a description in a textBox named descriptionBox which is identical to the value of the description value of for that entry in the database. I want the user to then be able to change the text of the text box (which they can currently do) and click the save button (saveBut) and have the form update all the values in the controls to the database. Theorectically, it should do this as the controls are DataBound, thus i can avoid writing code that tells each entry in the database row to take the value of the aligned control. I've tried calleding PropertiesTableAdapter.Update(PropertiesBindingSource.DataSource), but that doesnt seem to do it.

  Read the article

• Processing a database queue across multiple threads - design advice

  - by rwmnau

  I have a SQL Server table full of orders that my program needs to "follow up" on (call a webservice to see if something has been done with them). My application is multi-threaded, and could have instances running on multiple servers. Currently, every so often (on a Threading timer), the process selects 100 rows, at random (ORDER BY NEWID()), from the list of "unconfirmed" orders and checks them, marking off any that come back successfully. The problem is that there's a lot of overlap between the threads, and between the different processes, and their's no guarantee that a new order will get checked any time soon. Also, some orders will never be "confirmed" and are dead, which means that they get in the way of orders that need to be confirmed, slowing the process down if I keep selecting them over and over. What I'd prefer is that all outstanding orders get checked, systematically. I can think of two easy ways do this: The application fetches one order to check at a time, passing in the last order it checked as a parameter, and SQL Server hands back the next order that's unconfirmed. More database calls, but this ensures that every order is checked in a reasonable timeframe. However, different servers may re-check the same order in succession, needlessly. The SQL Server keeps track of the last order it asked a process to check up on, maybe in a table, and gives a unique order to every request, incrementing its counter. This involves storing the last order somewhere in SQL, which I wanted to avoid, but it also ensures that threads won't needlessly check the same orders at the same time Are there any other ideas I'm missing? Does this even make sense? Let me know if I need some clarification.

  Read the article

• What is the standard way to bundle OSGi dependent libraries?

  - by Chris

  Hi, I have a project that references a number of open source libraries, some new, some not so new. That said, they are all stable and I wish to stick with my chosen versions until I have time to migrate to the newer versions (I tested hsqldb 2.0 yesterday and it contains many api changes). One of the libraries I have wish to embed is Jasper Reports, but as you all surely know, it comes with a mountain of supporting jar files and I have only need a subset of the mountain (known) therefore I am planning to custom bundle all of my dependant libraries. So: Does everyone custom-make their own OSGi bundles for open-source libraries they are using or is there a master source of OSGi versions of common libraries? Also, I was thinking that it would be far simpler for each of my bundles simply to embed their dependent jars within the bundle itself. Is this possible? If I choose to embed the 3rd party foc libraries within a bundle, I assume I will need to produce 2 jar files, one without the embedded libraries (for libraries to be loaded via the classpath via standard classloader), and one osgi version that includes the embedded libraryy, therefore should I choose a bundle name like this <<myprojectname>>-<<subproject>>-osgi-.1.0.0.jar ? If I cannot embed the open source libraries and choose to custom bundle the open source libraries (via bnd), should I choose a unique bundle name to avoid conflict with a possible official bundle? e.g. <<myprojectname>>-<<3rdpartylibname>>-<<3rdpartylibversion>>.jar ? My non-OSGi enabled project currently scans for custom plugins via scanning the META-INF folders in my various plugin jars via Service.providers(...). If I go OSGi, will this mechanism still work?

  Read the article

• Django | passing form values

  - by MMRUser

  I want to create a user sign up process that requires two different forms with the same data one (1st form) is for filling out the data and other one (2nd form) is for displaying the filled data as a summery (before actually saving the data) so then user can view what he/she has filled up... my problem is that how do I pass 1st form's data in to the 2nd one .. I have used the basic Django form manipulation mechanism and passed the form field values to the next form using Django template tags.. if request.method == 'POST': form = Users(request.POST) if form.is_valid(): cd = form.cleaned_data try: name = cd['fullName'] email = cd['emailAdd'] password1 = cd['password'] password2 = cd['password2'] phoneNumber = cd['phoneNumber'] return render_to_response('signup2.html', {'name': name, 'email': email, 'password1': password1, 'password2': password2, 'phone': phone, 'pt': phoneType}) except Exception, ex: return HttpResponse("Error %s" % str(ex)) and from the second from I just displayed those field values using tags and also used hidden fields in order to submit the form with values, like this: <label for="">Email:</label> {{ email }} <input type="hidden" id="" name="email" class="width250" value="{{ email }}" readonly /> It works nicely from the out look, but the real problem is that if someone view the source of the html he can simply get the password even hackers can get through this easily. So how do I avoid this issue.. and I don't want to use Django session since this is just a simple sign up process and no other interactions involved. Thanks.

  Read the article

• Test the sequentiality of a column with a single SQL query

  - by LauriE

  Hey, I have a table that contains sets of sequential datasets, like that: ID set_ID some_column n 1 'set-1' 'aaaaaaaaaa' 1 2 'set-1' 'bbbbbbbbbb' 2 3 'set-1' 'cccccccccc' 3 4 'set-2' 'dddddddddd' 1 5 'set-2' 'eeeeeeeeee' 2 6 'set-3' 'ffffffffff' 2 7 'set-3' 'gggggggggg' 1 At the end of a transaction that makes several types of modifications to those rows, I would like to ensure that within a single set, all the values of "n" are still sequential (rollback otherwise). They do not need to be in the same order according to the PK, just sequential, like 1-2-3 or 3-1-2, but not like 1-3-4. Due to the fact that there might be thousands of rows within a single set I would prefer to do it in the db to avoid the overhead of fetching the data just for verification after making some small changes. Also there is the issue of concurrency. The way locking in InnoDB (repeatable read) works (as I understand) is that if I have an index on "n" then InnoDB also locks the "gaps" between values. If I combine set_ID and n to a single index, would that eliminate the problem of phantom rows appearing? Looks to me like a common problem. Any brilliant ideas? Thanks! Note: using MySQL + InnoDB

  Read the article

• Javascript, IE, Strings, and Performance problems

  - by Infinity

  Hey guys, So we have this product, and it's really slow in IE. We've already applied a lot of the practices advised by the IE guys themselves (like this, and this), and try to sacrifice clean code for performance in the critical parts like DOM manipulation. However, as you can see in this IE profiler screenshot.. Just "String" is the biggest offender. Almost 750ms of exclusive time. Does this mean IE is spending 750ms just instantiating Strings? I also read this stuff on the Opera dev blog: A build script can remove whitespace, comments, replace strings with Array lookups (to avoid MSIE creating a string object for every single instance of a string — even in conditions) But no more info regarding this. Anyone can clarify? It seems like IE has to create a full String instance every time you have " " in your code, which could explain this, but I don't know what the array lookup optimization would look like. BTW- we don't really do much of string concatenation anywhere in the code. The library we use is MooTools 1.2.4 Any suggestions will be appreciated! Thx

  Read the article

• Check a list of packages to install with apt-get

  - by Joel

  I am writing a post-install script for Ubuntu in Perl (same script as seen here). One of the steps is to install a list of packages. The problem is that if apt-get install fails in some of many different ways for any one of the packages the script dies badly. I would like to prevent that from happening. This happens because of the ways that apt-get install fails for packages that it doesn't like. For example when I try to install a nonsense word (i.e. typed in the wrong package name) $ sudo apt-get install oblihbyvl Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package oblihbyvl but if instead the package name has been obsoleted (installing handbrake from ppa) $ sudo apt-get install handbrake Reading package lists... Done Building dependency tree Reading state information... Done Package handbrake is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'handbrake' has no installation candidate $ apt-cache search handbrake handbrake-cli - versatile DVD ripper and video transcoder - command line handbrake-gtk - versatile DVD ripper and video transcoder - GTK GUI I have tried parsing the results of apt-cache and apt-get -s install to try to catch all possibilities before doing the install, but I seem to keep finding new ways to allow failures to continue to the actual install system command. My question is, is there some facility either in Perl (e.g. a module, though I would like to avoid installing modules if possible as this is supposed to be the first thing run after a new install of Ubuntu) or apt-* or dpkg that would let me be sure that the packages are all available to be installed before installing and if not fail gracefully in some way that lets the user decide what to do?

  Read the article

• Resources for setting up a Visual Studio/C++ development environment

  - by Tom H.

  I haven't done much "front-end" development in about 15 years since moving to database development. I'm planning to start work on a personal project using C++ and since I already have MSDN I'll probably end up doing it in Visual Studio 2010. I'm thinking about using Subversion as a version control system eventually. Of course, I'd like to get up and running as quickly as I can, but I'd also like to avoid any pitfalls from a poorly organized project environment. So, my question is, are there any good resources with common best practices for setting up a development environment? I'm thinking along the lines of where to break down a solution into multiple projects if necessary, how to set up a unit testing process, organizing resources, directories, etc. Are there any great add-ons that I should make sure I have set up from the start? Most tutorials just have one simple project, type in your code and click on build to see that your new application says, "Hello World!". This will be a Windows application with several DLLs as well (no web development), so there doesn't need to be a deploy to a web server kind of process. Mostly I just want to make sure that I don't miss anything big and then have to extensively refactor because of it. Thanks!

  Read the article

• Trie Backtracking in Recursion

  - by Darksky

  I am building a tree for a spell checker with suggestions. Each node contains a key (a letter) and a value (array of letters down that path). So assume the following sub-trie in my big trie: W / \ a e | | k k | | is word--> e e | ... This is just a subpath of a sub-trie. W is a node and a and e are two nodes in its value array etc... At each node, I check if the next letter in the word is a value of the node. I am trying to support mistyped vowels for now. So 'weke' will yield 'wake' as a suggestion. Here's my searchWord function in my trie: def searchWord(self, word, path=""): if len(word) > 0: key = word[0] word = word[1:] if self.values.has_key(key): path = path + key nextNode = self.values[key] return nextNode.searchWord(word, path) else: # check here if key is a vowel. If it is, check for other vowel substitutes else: if self.isWord: return path # this is the word found else: return None Given 'weke', at the end when word is of length zero and path is 'weke', my code will hit the second big else block. weke is not marked as a word and so it will return with None. This will return out of searchWord with None. To avoid this, at each stack unwind or recursion backtrack, I need to check if a letter is a vowel and if it is, do the checking again. I changed the if self.values.has_key(key) loop to the following: if self.values.has_key(key): path = path + key nextNode = self.values[key] ret = nextNode.searchWord(word, path) if ret == None: # check if key == vowel and replace path # return nextNode.searchWord(... return ret What am I doing wrong here? What can I do when backtracking to achieve what I'm trying to do?

  Read the article

• Handling Denormalized Schema with Eclipselink

  - by iamrohitbanga

  Hello All I have a denormalized table containing employee information. The fields are employee id, name and department name. The primary key is a composite one consisting of all three fields. An employee can belong to multiple departments. I want to read/write the objects in the table using the Eclipselink Dynamic Persistence API (which is infact a wrapper on top of JPA descriptors etc.). Example Data: 1 e1 dep1 2 e1 dep2 3 e2 dep1 4 e2 dep3 5 e3 dep1 5 e3 dep2 5 e3 dep3 A normal ReadAllQuery (select query) on the table returns a DynamicEntity corresponding to each row in the table. However I want to club all entities based on the emp id and return all the departments he belongs to as a list. I can merge the entities after retrieving them but if I can use some Eclipselink feature out of the box then it would be better. One way to do the read is the following: I create two dynamic types corresponding to employee: Having id,name as the primary key Having id, department as the primary key, I create a OneToManyMapping from the first type to the second one. Then when I query the first type it does return the departments to which employee belongs as a list of DynamicEntity of the second type. This satisfies the read scenario. Is there a better way of doing this? Is this inherently supported by Eclipselink or JPA? I cannot get the same dynamic type configuration working for the write scenario. This is because when I write the changes using the writeObject method of UnitOfWork, it generates insert queries which enter the following entries in the table id name department 102 emp_102 102 st 102 dep_102 102 dep_102 102 dep_102 instead of: id name department 102 emp_102 st 102 emp_102 dep_102 102 emp_102 dep_102 102 emp_102 dep_102 Is there any way I can get write to work with this schema using eclipselink? I want to avoid doing the heavy lifting of merging the rows for such a denormalized schema or generating each row before doing a write. Is there no clean way of doing this using Eclipselink or JPA? Thanks in Advance.

  Read the article

• Why would using a Temp table be faster than a nested query?

  - by Mongus Pong

  We are trying to optimise some of our queries. One query is doing the following: SELECT t.TaskID, t.Name as Task, '' as Tracker, t.ClientID, (<complex subquery>) Date, INTO [#Gadget] FROM task t SELECT TOP 500 TaskID, Task, Tracker, ClientID, dbo.GetClientDisplayName(ClientID) as Client FROM [#Gadget] order by CASE WHEN Date IS NULL THEN 1 ELSE 0 END , Date ASC DROP TABLE [#Gadget] (I have removed the complex subquery, cos I dont think its relevant other than to explain why this query has been done as a two stage process.) Now I would have thought it would be far more efficient to merge this down into a single query using subqueries as : SELECT TOP 500 TaskID, Task, Tracker, ClientID, dbo.GetClientDisplayName(ClientID) FROM ( SELECT t.TaskID, t.Name as Task, '' as Tracker, t.ClientID, (<complex subquery>) Date, FROM task t ) as sub order by CASE WHEN Date IS NULL THEN 1 ELSE 0 END , Date ASC This would give the optimiser better information to work out what was going on and avoid any temporary tables. It should be faster. But it turns out it is a lot slower. 8 seconds vs under 5 seconds. I cant work out why this would be the case as all my knowledge of databases imply that subqueries would always be faster than using temporary tables. Can anyone explain what could be going on!?!?

  Read the article

• C++ variable to const expression

  - by user1344784

  template <typename Real> class A{ }; template <typename Real> class B{ }; //... a few dozen more similar template classes class Computer{ public slots: void setFrom(int from){ from_ = from; } void setTo(int to){ to_ = to; } private: template <int F, int T> void compute(){ using boost::fusion::vector; using boost::fusion::at_c; vector<A<float>, B<float>, ...> v; at_c<from_>(v).operator()(at_c<to_>(v)); //error; needs to be const-expression. }; This question isn't about Qt, but there is a line of Qt code in my example. The setFrom() and setTo() are functions that are called based on user selection via the GUI widget. The root of my problem is that 'from' and 'to' are variables. In my compute member function I need to pick a type (A, B, etc.) based on the values of 'from' and 'to'. The only way I know how to do what I need to do is to use switch statements, but that's extremely tedious in my case and I would like to avoid. Is there anyway to convert the error line to a constant-expression?

  Read the article

< Previous Page | 484 485 486 487 488 489 490 491 492 493 494 495  | Next Page >