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  • Evaluating points in time by months, but without referencing years in Rails

    - by MikeH
    FYI, There is some overlap in the initial description of this question with a question I asked yesterday, but the question is different. My app has users who have seasonal products. When a user selects a product, we allow him to also select the product's season. We accomplish this by letting him select a start date and an end date for each product. We're using date_select to generate two sets of drop-downs: one for the start date and one for the end date. Including years doesn't make sense for our model. So we're using the option: discard_year => true When you use discard_year => true, Rails sets a year in the database, it just doesn't appear in the views. Rails sets all the years to either 0001 or 0002 in our app. Yes, we could make it 2009 and 2010 or any other pair. But the point is that we want the months and days to function independent of a particular year. If we used 2009 and 2010, then those dates would be wrong next year because we don't expect these records to be updated every year. My problem is that we need to dynamically evaluate the availability of products based on their relationship to the current month. For example, assume it's March 15. Regardless of the year, I need a method that can tell me that a product available from October to January is not available right now. If we were using actual years, this would be pretty easy. For example, in the products model, I can do this: def is_available? (season_start.past? && season_end.future?) end I can also evaluate a start_date and an end_date against current_date However, in setup I've described above where we have arbitrary years that only make sense relative to each other, these methods don't work. For example, is_available? would return false for all my products because their end date is in the year 0001 or 0002. What I need is a method just like the ones I used as examples above, except that they evaluate against current_month instead of current_date, and past? and future months instead of years. I have no idea how to do this or whether Rails has any built in functionality that could help. I've gone through all the date and time methods/helpers in the API docs, but I'm not seeing anything equivalent to what I'm describing. Thanks.

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  • C++ Unlocking a std::mutex before calling std::unique_lock wait

    - by Sant Kadog
    I have a multithreaded application (using std::thread) with a manager (class Tree) that executes some piece of code on different subtrees (embedded struct SubTree) in parallel. The basic idea is that each instance of SubTree has a deque that store objects. If the deque is empty, the thread waits until a new element is inserted in the deque or the termination criteria is reached. One subtree can generate objects and push them in the deque of another subtree. For convenience, all my std::mutex, std::locks and std::variable_condition are stored in a struct called "locks". The class Tree creates some threads that run the following method (first attempt) : void Tree::launch(SubTree & st, Locks & locks ) { /* some code */ std::lock_guard<std::mutex> deque_lock(locks.deque_mutex_[st.id_]) ; // lock the access to the deque of subtree st if (st.deque_.empty()) // check that the deque is still empty { // some threads are still running, wait for them to terminate std::unique_lock<std::mutex> wait_lock(locks.restart_mutex_[st.id_]) ; locks.restart_condition_[st.id_].wait(wait_lock) ; } /* some code */ } The problem is that "deque_lock" is still locked while the thread is waiting. Hence no object can be added in the deque of the current thread by a concurrent one. So I turned the lock_guard into a unique_lock and managed the lock/unlock manually : void launch(SubTree & st, Locks & locks ) { /* some code */ std::unique_lock<std::mutex> deque_lock(locks.deque_mutex_[st.id_]) ; // lock the access to the deque of subtree st if (st.deque_.empty()) // check that the deque is still empty { deque_lock.unlock() ; // unlock the access to the deque to enable the other threads to add objects // DATA RACE : nothing must happen to the unprotected deque here !!!!!! // some threads are still running, wait for them to terminate std::unique_lock<std::mutex> wait_lock(locks.restart_mutex_[st.id_]) ; locks.restart_condition_[st.id_].wait(wait_lock) ; } /* some code */ } The problem now, is that there is a data race, and I would like to make sure that the "wait" instruction is performed directly after the "deque_lock.unlock()" one. Would anyone know a way to create such a critical instruction sequence with the standard library ? Thanks in advance.

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  • How to develop asp.net web service to create the web method which can take the parameter of type win

    - by Shailesh Jaiswal
    I am developing asp.net web service. I am developing this web service so that OPC ( OLE for process control) client application can use it. In this web service I am using the built-in functions provided by the namespaces using OPC, using OPCDA, using OPCDA.NET. I have also added the namespace using System.Windows.Forms in this web service so that I can use the windows form control. In that we service I have created on web method which takes the parameter of type windows form control as given below. public void getOPCServerItems(TreeView tvServerItems, ListView lvBranchItems) { ArrayList ArrlstObj = new ArrayList(); ItemShowTreeList = OpcSrv.ShowBrowseTreeList(tvServerItems, lvBranchItems); ItemShowTreeList.BrowseModeOneLevel = true; // browse hierachy levels when selected. (default) ItemShowTreeList.Show(OpcSrv.ServerName); } In the above web method I need to pass the values to the built-in function ShowBrowseTreeList() (found in OPC, OPCDA, OPCDA.NET namespaces). This function takes the two parameter of windows form control type. These parameters are Treeview & ListView control of the windows form. In the above web method ShowBrowseTreeList() method automatically create the treeview & listview structure of the available items. Now as I am consuming the web service so I need to pass the values to the webmethod getOPCServerItems(). But as I my consuming application is asp.net application there is no such windows form control. In asp.net application there are also & control. I want to display The data returned in these asp.net controls rather than windows form control. I am not getting the way what should I need to do or how should I pass the values form my client application to this web service ? In the above method getOPCServerItems() when I use the parameter of type treeview & listview it generate s error "Cannot serialize member System.ComponentModel.Component.Site of type System.ComponentModel.ISite because it is an interface.". Can you provide me the the way In which I can write the above web method & how should I pass parameter to the Treeview & Listview control (windows form control) from my asp.net application ? which controls I should use to pass parameters ? Is there any need to do any type of casting ? Can you provide me the the code for above web method so that I can resolve the above issue ?

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  • All embedded databases fail to open connections

    - by rsteckly
    Hi, I'm working on a winforms desktop application that needs to store data. I made the really bad decision to try and embed a database. I've tried: SQLite VistaDB SQL Server Compact In each case, I was able to generate a Entity Framework Model over the basic schema I've created. I have an event that adds data that I've been using to test these databases. Well, I kept adding a new record using EF and finding it didn't actually insert a record. In debugging, I checked the context object to see what was happening. It turns out that it is saying "the underlying provider failed to open," or something to that effect. It was not throwing an exception, just not inserting a record. The same thing has happened for all 3 embedded databases--prompting me to get it through my dense head that there has to be something wrong with my configuration. Well, I tried to write some basic sql using a sqlconnection and sqlcommand. This time it throws an exception. In the SQL Server Compact case, it now says: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) I thought perhaps a problem was the path in app.Config. So I changed the connection string to: Note that I simplified the path away from anything that might have spaces and avoided using the Data Directory nonsense that causes problem when the debugging directory does not match the preconfigured value for the data directory. I'm running Windows 7; I thought perhaps it might be an access issue--so I tried running VS 2010 in Administrator mode. No luck. I also installed Sql Server Compact SP2, thinking this might be a bug. No luck. Anyway, I'm ready to pull my hair out. I'm on a tight deadline for this thing and didn't expect to spend the day trying to figure out what is going on.

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  • How to get hibernate3-maven-plugin hbm2ddl to find JDBC driver?

    - by HDave
    I have a Java project I am building with Maven. I am now trying to get the hibernate3-maven-plugin to run the hbm2ddl tool to generate a schema.sql file I can use to create the database schema from my annotated domain classes. This is a JPA application that uses Hibernate as the provider. In my persistence.xml file I call out the mysql driver: <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/> <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/> When I run Maven, I see it processing all my classes, but when it goes to output the schema, I get the following error: ERROR org.hibernate.connection.DriverManagerConnectionProvider - JDBC Driver class not found: com.mysql.jdbc.Driver java.lang.ClassNotFoundException: com.mysql.jdbc.Driver I have the MySQL driver as a dependency of this module. However it seems like the hbm2ddl tool cannot find it. I would have guessed that the Maven plugin would have known to search the local Maven file repository for this driver. What gives? The relevant part of my pom.xml is this: <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>hibernate3-maven-plugin</artifactId> <executions> <execution> <phase>process-classes</phase> <goals> <goal>hbm2ddl</goal> </goals> </execution> </executions> <configuration> <components> <component> <name>hbm2ddl</name> <implementation>jpaconfiguration</implementation> </component> </components> <componentProperties> <persistenceunit>my-unit</persistenceunit> </componentProperties> </configuration> </plugin>

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  • How do I get git whatchanged to show a combined list of files that have changed?

    - by Chirag Patel
    I ran the following comand git whatchanged 7c8358e.. --oneline and got the below output. Is there a way to generate a single combined list of files that changed across all commits? In other words, I don't want files to show up more than once in the below list. Thanks! 4545ed7 refs #2911. error on 'caregivers_sorted_by_position' resolved in this update. it came up randomly in cucumber :100644 100644 d750be7... 11a0bd0... M app/controllers/reporting_controller.rb :100644 100644 7334d4d... e43d9e6... M app/models/user.rb e9b2748 refs #2911. group dropdown filters the list to only the users that belong to the selected group :100644 100644 fc81b9a... d750be7... M app/controllers/reporting_controller.rb :100644 100644 aaf2398... f19038e... M app/models/group.rb :100644 100644 3cc3635... 7a6b2b1... M app/views/reporting/users.html.erb 48149c9 refs #2888 cherry pick 2888 from master into prod-temp :100644 100644 3663ecc... f672b62... M app/controllers/user_admin_controller.rb :100644 100644 aaf2398... 056ea36... M app/models/group.rb :100644 100644 32363ef... bc9a1f2... M app/models/role.rb :100644 100644 91283fa... 7334d4d... M app/models/user.rb :100644 100644 d6393a0... bae1bd6... M app/views/user_admin/roles.html.erb 994550d refs #2890. all requirements included. cucumber has 1 exception in bundle_job for count of data rows. everything else green :100644 100644 145122d... 869a005... M app/controllers/profiles_controller.rb :100644 100644 f1bfa77... 2ed0850... M app/views/alerts/message.html.erb :100644 100644 e9f8a34... f358a74... M app/views/call_list/_item.html.erb :100644 000000 fda1297... 0000000... D app/views/call_list/_load_caregivers.erb :000000 100644 0000000... fda1297... A app/views/call_list/_load_caregivers.html.erb :100644 100644 168de9e... 43594f4... M app/views/call_list/show.html.erb :100644 100644 e178d7f... 0fe77e1... M app/views/profiles/edit_caregiver_profile.html.erb 7396ff6 refs #2890. fixed --we're sorry-- error :100644 100644 d55d46d... fc81b9a... M app/controllers/reporting_controller.rb 7c8358e refs #2897 link on online store back to http://www.halomonitoring.com :100644 100644 d6f94f4... 8bc9c52... M app/views/orders/new.html.erb

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  • stop and split generated sequence at repeats - clojure

    - by fitzsnaggle
    I am trying to make a sequence that will only generate values until it finds the following conditions and return the listed results: case head = 0 - return {:origin [all generated except 0] :pattern 0} 1 - return {:origin nil :pattern [all-generated-values] } repeated-value - {:origin [values-before-repeat] :pattern [values-after-repeat] { ; n = int ; x = int ; hist - all generated values ; Keeps the head below x (defn trim-head [head x] (loop [head head] (if (> head x) (recur (- head x)) head))) ; Generates the next head (defn next-head [head x n] (trim-head (* head n) x)) (defn row [x n] (iterate #(next-head % x n) n)) ; Generates a whole row - ; Rows are a max of x - 1. (take (- x 1) (row 11 3)) Examples of cases to stop before reaching end of row: [9 8 4 5 6 7 4] - '4' is repeated so STOP. Return preceding as origin and rest as pattern. {:origin [9 8] :pattern [4 5 6 7]} [4 5 6 1] - found a '1' so STOP, so return everything as pattern {:origin nil :pattern [4 5 6 1]} [3 0] - found a '0' so STOP {:origin [3] :pattern [0]} :else if the sequences reaches a length of x - 1: {:origin [all values generated] :pattern nil} The Problem I have used partition-by with some success to split the groups at the point where a repeated value is found, but would like to do this lazily. Is there some way I can use take-while, or condp, or the :while clause of the for loop to make a condition that partitions when it finds repeats? Some Attempts (take 2 (partition-by #(= 1 %) (row 11 4))) (for [p (partition-by #(stop-match? %) head) (iterate #(next-head % x n) n) :while (or (not= (last p) (or 1 0 n) (nil? (rest p))] {:origin (first p) :pattern (concat (second p) (last p))})) # Updates What I really want to be able to do is find out if a value has repeated and partition the seq without using the index. Is that possible? Something like this - { (defn row [x n] (loop [hist [n] head (gen-next-head (first hist) x n) steps 1] (if (>= (- x 1) steps) (case head 0 {:origin [hist] :pattern [0]} 1 {:origin nil :pattern (conj hist head)} ; Speculative from here on out (let [p (partition-by #(apply distinct? %) (conj hist head))] (if-not (nil? (next p)) ; One partition if no repeats. {:origin (first p) :pattern (concat (second p) (nth 3 p))} (recur (conj hist head) (gen-next-head head x n) (inc steps))))) {:origin hist :pattern nil}))) }

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  • Adobe Reader process fails when starting second instance

    - by Reddog
    In our C# WinForms application, we generate PDF files and launch Adobe Reader (or whatever the default system .pdf handler is) via the Process class. Since our PDF files can be large (approx 200K), we handle the Exited event to then clean up the temp file afterwards. The system works as required when a file is opened and then closed again. However, when a second file is opened (before closing Adobe Reader) the second process immediately exits (since Reader is now using it's MDI powers) and in our Exited handler our File.Delete call should fail because it's locked by the now joined Adobe process. However, in Reader we instead get: There was an error opening this document. This file cannot be found. The unusual thing is that if I put a debugger breakpoint before the file deletion and allow it to attempt (and fail) the deletion, then the system behaves as expected! I'm positive that the file exists and fairly positive that all handles/file streams to the file are closed before starting the process. We are launching with the following code: // Open the file for viewing/printing (if the default program supports it) var pdfProcess = new Process(); pdfProcess.StartInfo.FileName = tempFileName; if (pdfProcess.StartInfo.Verbs.Contains("open", StringComparer.InvariantCultureIgnoreCase)) { var verb = pdfProcess.StartInfo.Verbs.First(v => v.Equals("open", StringComparison.InvariantCultureIgnoreCase)); pdfProcess.StartInfo.Verb = verb; } pdfProcess.StartInfo.Arguments = "/N"; // Specifies a new window will be used! (But not definitely...) pdfProcess.SynchronizingObject = this; pdfProcess.EnableRaisingEvents = true; pdfProcess.Exited += new EventHandler(pdfProcess_Exited); _pdfProcessDictionary.Add(pdfProcess, tempFileName); pdfProcess.Start(); Note: We are using the _pdfProcessDictionary to store references to the Process objects so that they stay in scope so that Exited event can successfully be raised. Our cleanup/exited event is: void pdfProcess_Exited(object sender, EventArgs e) { Debug.Assert(!InvokeRequired); var p = sender as Process; try { if (_pdfProcessDictionary.ContainsKey(p)) { var tempFileName = _pdfProcessDictionary[p]; if (File.Exists(tempFileName)) // How else can I check if I can delete it!!?? { // NOTE: Will fail if the Adobe Reader application instance has been re-used! File.Delete(tempFileName); _pdfProcessDictionary.Remove(p); } CleanOtherFiles(); // This function will clean up files for any other previously exited processes in our dictionary } } catch (IOException ex) { // Just swallow it up, we will deal with trying to delete it at another point } } Possible solutions: Detect that the file is still open in another process Detect that the second process hasn't really been fully exited and that the file is opened in the first process instead

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  • How do you implement position-sensitive zooming inside a JScrollPane?

    - by tucuxi
    I am trying to implement position-sensitive zooming inside a JScrollPane. The JScrollPane contains a component with a customized 'paint' that will draw itself inside whatever space it is allocated - so zooming is as easy as using a MouseWheelListener that resizes the inner component as required. But I also want zooming into (or out of) a point to keep that point as central as possible within the resulting zoomed-in (or -out) view (this is what I refer to as 'position-sensitive' zooming), similar to how zooming works in google maps. I am sure this has been done many times before - does anybody know the "right" way to do it under Java Swing?. Would it be better to play with Graphic2D's transformations instead of using JScrollPanes? Sample code follows: package test; import java.awt.*; import java.awt.event.*; import java.awt.geom.*; import javax.swing.*; public class FPanel extends javax.swing.JPanel { private Dimension preferredSize = new Dimension(400, 400); private Rectangle2D[] rects = new Rectangle2D[50]; public static void main(String[] args) { JFrame jf = new JFrame("test"); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jf.setSize(400, 400); jf.add(new JScrollPane(new FPanel())); jf.setVisible(true); } public FPanel() { // generate rectangles with pseudo-random coords for (int i=0; i<rects.length; i++) { rects[i] = new Rectangle2D.Double( Math.random()*.8, Math.random()*.8, Math.random()*.2, Math.random()*.2); } // mouse listener to detect scrollwheel events addMouseWheelListener(new MouseWheelListener() { public void mouseWheelMoved(MouseWheelEvent e) { updatePreferredSize(e.getWheelRotation(), e.getPoint()); } }); } private void updatePreferredSize(int n, Point p) { double d = (double) n * 1.08; d = (n > 0) ? 1 / d : -d; int w = (int) (getWidth() * d); int h = (int) (getHeight() * d); preferredSize.setSize(w, h); getParent().doLayout(); // Question: how do I keep 'p' centered in the resulting view? } public Dimension getPreferredSize() { return preferredSize; } private Rectangle2D r = new Rectangle2D.Float(); public void paint(Graphics g) { super.paint(g); g.setColor(Color.red); int w = getWidth(); int h = getHeight(); for (Rectangle2D rect : rects) { r.setRect(rect.getX() * w, rect.getY() * h, rect.getWidth() * w, rect.getHeight() * h); ((Graphics2D)g).draw(r); } } }

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  • Complex relationship between tables in NHibernate

    - by Ilya Kogan
    Hi all, I'm writing a Fluent NHibernate mapping for a legacy Oracle database. The challenge is that the tables have composite primary keys. If I were at total freedom, I would redesign the relationships and auto-generate primary keys, but other applications must write to the same database and read from it, so I cannot do it. These are the two tables I'll focus on: Example data Trips table: 1, 10:00, 11:00 ... 1, 12:00, 15:00 ... 1, 16:00, 19:00 ... 2, 12:00, 13:00 ... 3, 9:00, 18:00 ... Faults table: 1, 13:00 ... 1, 23:00 ... 2, 12:30 ... In this case, vehicle 1 made three trips and has two faults. The first fault happened during the second trip, and the second fault happened while the vehicle was resting. Vehicle 2 had one trip, during which a fault happened. Constraints Trips of the same vehicle never overlap. So the tables have an optional one-to-many relationship, because every fault either happens during a trip or it doesn't. If I wanted to join them in SQL, I would write: select ... from Faults left outer join Trips on Faults.VehicleId = Trips.VehicleId and Faults.FaultTime between Trips.TripStartTime and Trips.TripEndTime and then I'd get a dataset where every fault appears exactly once (one-to-many as I said). Note that there is no Vehicles table, and I don't need one. But I did create a view that contains all VehicleIds from both tables, so I can use it as a junction table. What am I actually looking for? The tables are huge because they cover years of data, and every time I only need to fetch a range of a few hours. So I need a mapping and a criteria that will run something like the following SQL underneath: select ... from Faults left outer join Trips on Faults.VehicleId = Trips.VehicleId and Faults.FaultTime between Trips.TripStartTime and Trips.TripEndTime where Faults.FaultTime between :p0 and :p1 Do you have any ideas how to achieve it? Note 1: Currently the application shouldn't write to the database, so persistence is not a must, although if the mapping supports persistence, it may help at some point in the future. Note 2: I know it's a tough one, so if you give me a great answer, you will be properly rewarded :) Thank you for reading this long question, and now I only hope for the best :)

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  • DataAnnotation attributes buddy class strangeness - ASP.NET MVC

    - by JK
    Given this POCO class that was automatically generated by an EntityFramework T4 template (has not and can not be manually edited in any way): public partial class Customer { [Required] [StringLength(20, ErrorMessage = "Customer Number - Please enter no more than 20 characters.")] [DisplayName("Customer Number")] public virtual string CustomerNumber { get;set; } [Required] [StringLength(10, ErrorMessage = "ACNumber - Please enter no more than 10 characters.")] [DisplayName("ACNumber")] public virtual string ACNumber{ get;set; } } Note that "ACNumber" is a badly named database field, so the autogenerator is unable to generate the correct display name and error message which should be "Account Number". So we manually create this buddy class to add custom attributes that could not be automatically generated: [MetadataType(typeof(CustomerAnnotations))] public partial class Customer { } public class CustomerAnnotations { [NumberCode] // This line does not work public virtual string CustomerNumber { get;set; } [StringLength(10, ErrorMessage = "Account Number - Please enter no more than 10 characters.")] [DisplayName("Account Number")] public virtual string ACNumber { get;set; } } Where [NumberCode] is a simple regex based attribute that allows only digits and hyphens: [AttributeUsage(AttributeTargets.Property)] public class NumberCodeAttribute: RegularExpressionAttribute { private const string REGX = @"^[0-9-]+$"; public NumberCodeAttribute() : base(REGX) { } } NOW, when I load the page, the DisplayName attribute works correctly - it shows the display name from the buddy class not the generated class. The StringLength attribute does not work correctly - it shows the error message from the generated class ("ACNumber" instead of "Account Number"). BUT the [NumberCode] attribute in the buddy class does not even get applied to the AccountNumber property: foreach (ValidationAttribute attrib in prop.Attributes.OfType<ValidationAttribute>()) { // This collection correctly contains all the [Required], [StringLength] attributes // BUT does not contain the [NumberCode] attribute ApplyValidation(generator, attrib); } Why does the prop.Attributes.OfType<ValidationAttribute>() collection not contain the [NumberCode] attribute? NumberCode inherits RegularExpressionAttribute which inherits ValidationAttribute so it should be there. If I manually move the [NumberCode] attribute to the autogenerated class, then it is included in the prop.Attributes.OfType<ValidationAttribute>() collection. So what I don't understand is why this particular attribute does not work in when in the buddy class, when other attributes in the buddy class do work. And why this attribute works in the autogenerated class, but not in the buddy. Any ideas? Also why does DisplayName get overriden by the buddy, when StringLength does not?

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  • How can I make Swig correctly wrap a char* buffer that is modified in C as a Java Something-or-other

    - by Ukko
    I am trying to wrap some legacy code for use in Java and I was quite happy to see that Swig was able to handle the header file and it generate a great wrapper that almost works. Now I am looking for the deep magic that will make it really work. In C I have a function that looks like this DLL_IMPORT int DustyVoodoo(char *buff, int len, char *curse); This integer returned by this function is an error code in case it fails. The arguments are buff is a character buffer len is the length of the data in the buffer curse the another character buffer that contains the result of calling DustyVoodoo So, you can see where this is going, the result is actually coming back via the third argument. Also len is confusing since it may be the length of both buffers, they are always allocated as being the same size in calling code but given what DustyVoodoo does I don't think that they need be the same. To be safe both buffers should be the same size in practice, say 512 chars. The C code generated for the binding is as follows: SWIGEXPORT jint JNICALL Java_pemapiJNI_DustyVoodoo(JNIEnv *jenv, jclass jcls, jstring jarg1, jint jarg2, jstring jarg3) { jint jresult = 0 ; char *arg1 = (char *) 0 ; int arg2 ; char *arg3 = (char *) 0 ; int result; (void)jenv; (void)jcls; arg1 = 0; if (jarg1) { arg1 = (char *)(*jenv)->GetStringUTFChars(jenv, jarg1, 0); if (!arg1) return 0; } arg2 = (int)jarg2; arg3 = 0; if (jarg3) { arg3 = (char *)(*jenv)->GetStringUTFChars(jenv, jarg3, 0); if (!arg3) return 0; } result = (int)PemnEncrypt(arg1,arg2,arg3); jresult = (jint)result; if (arg1) (*jenv)->ReleaseStringUTFChars(jenv, jarg1, (const char *)arg1); if (arg3) (*jenv)->ReleaseStringUTFChars(jenv, jarg3, (const char *)arg3); return jresult; } It is correct for what it does; however, it misses the fact that cursed is not just an input, it is altered by the function and should be returned as an output. It also does not know that the java Strings are really buffers and should be backed by a suitably sized array. I think that Swig can do the right thing here, I just can't figure out from the documentation how to tell Swig what it needs to know. Any typemap masers in the house?

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  • How to store result of drag and drop as a image

    - by Jimmy
    I want to take the screenshot of the result of drag and drop, but I don't know how to do. Actually, I found 2 javascript and using HTML5 such as html2canvas and canvas2image. I am now combining them together, but it's still meet some problem with the canvas2image. Please help me solve this problem if you have same experience, thank you a lot. Please help me, I've been stock here for days. Drag and drop code. <script> $(function() { $( "#draggable" ).draggable(); $( "#draggable2" ).draggable(); $( "#droppable" ).droppable({ hoverClass: "ui-state-active", drop: function( event, ui ) { $( this ) .addClass( "ui-state-highlight" ) .find( "p" ) .html( "Dropped!" ); } }); }); </script> Image generation code <script> window.onload = function() { function convertCanvas(strType) { if (strType == "JPEG") var oImg = Canvas2Image.saveAsJPEG(oCanvas, true); if (!oImg) { alert("Sorry, this browser is not capable of saving " + strType + " files!"); return false; } oImg.id = "canvasimage"; oImg.style.border = oCanvas.style.border; oCanvas.parentNode.replaceChild(oImg, oCanvas); } function convertHtml(strType) { $('body').html2canvas(); var queue = html2canvas.Parse(); var canvas = html2canvas.Renderer(queue,{elements:{length:1}}); var img = canvas.toDataURL(); convertCanvas(strType); window.open(img); } document.getElementById("html2canvasbtn").onclick = function() { convertHtml("JPEG"); } } </script> HTML code <body> <h3>Picture:</h3> <div id="draggable"> <img src='http://1.gravatar.com/avatar/1ea64135b09e00ab80fa7596fafbd340? s=50&d=identicon&r=R'> </div> <div id="draggable2"> <img src='http://0.gravatar.com/avatar/2647a7d4b4a7052d66d524701432273b?s=50&d=identicon&r=G'> </div> <div id="dCanvas"> <canvas id="droppable" width="500" height="500" style="border: 2px solid gray" class="ui-widget-header" /> </div> <input type="button" id="bGenImage" value="Generate Image" /> <div id="dOutput"></div> </body>

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  • TicTacToe AI Making Incorrect Decisions

    - by Chris Douglass
    A little background: as a way to learn multinode trees in C++, I decided to generate all possible TicTacToe boards and store them in a tree such that the branch beginning at a node are all boards that can follow from that node, and the children of a node are boards that follow in one move. After that, I thought it would be fun to write an AI to play TicTacToe using that tree as a decision tree. TTT is a solvable problem where a perfect player will never lose, so it seemed an easy AI to code for my first time trying an AI. Now when I first implemented the AI, I went back and added two fields to each node upon generation: the # of times X will win & the # of times O will win in all children below that node. I figured the best solution was to simply have my AI on each move choose and go down the subtree where it wins the most times. Then I discovered that while it plays perfect most of the time, I found ways where I could beat it. It wasn't a problem with my code, simply a problem with the way I had the AI choose it's path. Then I decided to have it choose the tree with either the maximum wins for the computer or the maximum losses for the human, whichever was more. This made it perform BETTER, but still not perfect. I could still beat it. So I have two ideas and I'm hoping for input on which is better: 1) Instead of maximizing the wins or losses, instead I could assign values of 1 for a win, 0 for a draw, and -1 for a loss. Then choosing the tree with the highest value will be the best move because that next node can't be a move that results in a loss. It's an easy change in the board generation, but it retains the same search space and memory usage. Or... 2) During board generation, if there is a board such that either X or O will win in their next move, only the child that prevents that win will be generated. No other child nodes will be considered, and then generation will proceed as normal after that. It shrinks the size of the tree, but then I have to implement an algorithm to determine if there is a one move win and I think that can only be done in linear time (making board generation a lot slower I think?) Which is better, or is there an even better solution?

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  • Share a "deep link" from a Windows 8/WinRT application

    - by Dave Parker
    I have searched using many different terms and phrases, and waded through many pages of results, but I have (remarkably) not seen anyone else addressing, even asking, about, this issue. So here goes... Ultimate Goal: Allow a user viewing a content-based page (may contain both text and images) within a Windows Store app to share that content with someone else. Description I am working on taking a fair amount of content and making it available for browsing/navigating as a Windows 8/WinRT/Windows Store (we need a consistent name here) application. One of the desired features is to take advantage of the Share Charm, such that someone viewing a page could share that page with someone else. The ideal behavior is for the application to implement the Share Source contract which would share an email message that contained some explanatory text, a link to get the app from the Windows Store, and a "deep link" into the shared page in the application. Solutions Considered We had originally looked at just generating a PDF representation of the page, but there are very few external libraries that would work under WinRT, and having to include externally licensed code would be problematic as well. Writing our own PDF generation code would out of scope. We have also considered generating a Word document or PowerPoint slide using OpenXML, but again, we run up against the limitaions of WinRT. In this case, it is highly unlikely the OpenXML SDK is useable in a WinRT application. Another thought was to pre-generate all of the pages as .pdf files, store them as resources, and when the Share Charm is invoked, share the .pdf file associated with the current page. The problem here is the application will have at least 150 content pages, and depending on how we break the content down, up to over 600. This would likely cause serious bloat. Where We Are At Thus we have come to sharing URIs. From what I can tell, though, the "deep linking" feature is only intended for use on Secondary Tiles tied to your application. Another avenue I considered was registering a protocol like, "my-special-app:" with the OS and having it fire up the application but that would require HKCR registry access, which is outside the WinRT sandbox. If it matters, we are leaning towards an HTML/JS application, rather than XAML/C#, because the converted content will all be in HTML and the WebView control in WinRT is fairly limited. This decision is not yet final, though. Conclusion So, is this possible, and if so, how would it be done or where can I find documentation on it? Thanks, Dave Parker

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  • How to verify if the private key matches with the certificate..?

    - by surendhar_s
    I have the private key stored as .key file.. -----BEGIN RSA PRIVATE KEY----- MIICXAIBAAKBgQD5YBS6V3APdgqaWAkijIUHRK4KQ6eChSaRWaw9L/4u8o3T1s8J rUFHQhcIo5LPaQ4BrIuzHS8yzZf0m3viCTdZAiDn1ZjC2koquJ53rfDzqYxZFrId 7a4QYUCvM0gqx5nQ+lw1KoY/CDAoZN+sO7IJ4WkMg5XbgTWlSLBeBg0gMwIDAQAB AoGASKDKCKdUlLwtRFxldLF2QPKouYaQr7u1ytlSB5QFtIih89N5Avl5rJY7/SEe rdeL48LsAON8DpDAM9Zg0ykZ+/gsYI/C8b5Ch3QVgU9m50j9q8pVT04EOCYmsFi0 DBnwNBRLDESvm1p6NqKEc7zO9zjABgBvwL+loEVa1JFcp5ECQQD9/sekGTzzvKa5 SSVQOZmbwttPBjD44KRKi6LC7rQahM1PDqmCwPFgMVpRZL6dViBzYyWeWxN08Fuv p+sIwwLrAkEA+1f3VnSgIduzF9McMfZoNIkkZongcDAzjQ8sIHXwwTklkZcCqn69 qTVPmhyEDA/dJeAK3GhalcSqOFRFEC812QJAXStgQCmh2iaRYdYbAdqfJivMFqjG vgRpP48JHUhCeJfOV/mg5H2yDP8Nil3SLhSxwqHT4sq10Gd6umx2IrimEQJAFNA1 ACjKNeOOkhN+SzjfajJNHFyghEnJiw3NlqaNmEKWNNcvdlTmecObYuSnnqQVqRRD cfsGPU661c1MpslyCQJBAPqN0VXRMwfU29a3Ve0TF4Aiu1iq88aIPHsT3GKVURpO XNatMFINBW8ywN5euu8oYaeeKdrVSMW415a5+XEzEBY= -----END RSA PRIVATE KEY----- And i extracted public key from ssl certificate file.. Below is the code i tried to verify if private key matches with ssl certificate or not.. I used the modulus[i.e. private key get modulus==public key get modulus] to check if they are matching.. And this seems to hold only for RSAKEYS.. But i want to check for other keys as well.. Is there any other alternative to do the same..?? private static boolean verifySignature(File serverCertificateFile, File serverCertificateKey) { try { byte[] certificateBytes = FileUtils.readFileToByteArray(serverCertificateFile); //byte[] keyBytes = FileUtils.readFileToByteArray(serverCertificateKey); RandomAccessFile raf = new RandomAccessFile(serverCertificateKey, "r"); byte[] buf = new byte[(int) raf.length()]; raf.readFully(buf); raf.close(); PKCS8EncodedKeySpec kspec = new PKCS8EncodedKeySpec(buf); KeyFactory kf; try { kf = KeyFactory.getInstance("RSA"); RSAPrivateKey privKey = (RSAPrivateKey) kf.generatePrivate(kspec); CertificateFactory certFactory = CertificateFactory.getInstance("X.509"); InputStream in = new ByteArrayInputStream(certificateBytes); //Generate Certificate in X509 Format X509Certificate cert = (X509Certificate) certFactory.generateCertificate(in); RSAPublicKey publicKey = (RSAPublicKey) cert.getPublicKey(); in.close(); return privKey.getModulus() == publicKey.getModulus(); } catch (NoSuchAlgorithmException ex) { logger.log(Level.SEVERE, "Such algorithm is not found", ex); } catch (CertificateException ex) { logger.log(Level.SEVERE, "certificate exception", ex); } catch (InvalidKeySpecException ex) { Logger.getLogger(CertificateConversion.class.getName()).log(Level.SEVERE, null, ex); } } catch (IOException ex) { logger.log(Level.SEVERE, "Signature verification failed.. This could be because the file is in use", ex); } return false; } And the code isn't working either.. throws invalidkeyspec exception

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  • Can parser combination be made efficient?

    - by Jon Harrop
    Around 6 years ago, I benchmarked my own parser combinators in OCaml and found that they were ~5× slower than the parser generators on offer at the time. I recently revisited this subject and benchmarked Haskell's Parsec vs a simple hand-rolled precedence climbing parser written in F# and was surprised to find the F# to be 25× faster than the Haskell. Here's the Haskell code I used to read a large mathematical expression from file, parse and evaluate it: import Control.Applicative import Text.Parsec hiding ((<|>)) expr = chainl1 term ((+) <$ char '+' <|> (-) <$ char '-') term = chainl1 fact ((*) <$ char '*' <|> div <$ char '/') fact = read <$> many1 digit <|> char '(' *> expr <* char ')' eval :: String -> Int eval = either (error . show) id . parse expr "" . filter (/= ' ') main :: IO () main = do file <- readFile "expr" putStr $ show $ eval file putStr "\n" and here's my self-contained precedence climbing parser in F#: let rec (|Expr|) (P(f, xs)) = Expr(loop (' ', f, xs)) and shift oop f op (P(g, xs)) = let h, xs = loop (op, g, xs) loop (oop, f h, xs) and loop = function | ' ' as oop, f, ('+' | '-' as op)::P(g, xs) | (' ' | '+' | '-' as oop), f, ('*' | '/' as op)::P(g, xs) | oop, f, ('^' as op)::P(g, xs) -> let h, xs = loop (op, g, xs) let op = match op with | '+' -> (+) | '-' -> (-) | '*' -> (*) | '/' -> (/) | '^' -> pown loop (oop, op f h, xs) | _, f, xs -> f, xs and (|P|) = function | '-'::P(f, xs) -> let f, xs = loop ('~', f, xs) P(-f, xs) | '('::Expr(f, ')'::xs) -> P(f, xs) | c::xs when '0' <= c && c <= '9' -> P(int(string c), xs) My impression is that even state-of-the-art parser combinators waste a lot of time back tracking. Is that correct? If so, is it possible to write parser combinators that generate state machines to obtain competitive performance or is it necessary to use code generation?

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  • How to stream XML data using XOM?

    - by Jonik
    Say I want to output a huge set of search results, as XML, into a PrintWriter or an OutputStream, using XOM. The resulting XML would look like this: <?xml version="1.0" encoding="UTF-8"?> <resultset> <result> [child elements and data] </result> ... ... [1000s of result elements more] </resultset> Because the resulting XML document could be big (tens or hundreds of megabytes, perhaps), I want to output it in a streaming fashion (instead of creating the whole Document in memory and then writing that). The granularity of outputting one <result> at a time is fine, so I want to generate one <result> after another, and write it into the stream. Assume there's already a method that helps with iterating the results and generating Element objects: public nu.xom.Element getNextResult(); So I'd simply like to do something like this pseudocode (automatic flushing enabled, so don't worry about that) : open stream/writer write declaration write start tag for <resultset> while more results: write next <result> element write end tag for <resultset> close stream/writer I've been looking at Serializer, but the necessary methods, writeStartTag(Element), writeEndTag(Element), write(DocType) are protected, not public! Is there no other way than to subclass Serializer to be able to use those methods, or to manually write the start and end tags directly into the stream as Strings, bypassing XOM altogether? (The latter wouldn't be too bad in this simple example, but in the general case it would get quite ugly.) Am I missing something or is XOM just not made for this? With dom4j I could do this easily using XMLWriter - it has constructors that take a Writer or OutputStream, and methods writeOpen(Element), writeClose(Element), writeDocType(DocumentType) etc. Compare to XOM's Serializer where the only public write method is the one that takes a whole Document. Please refrain from answering if you're not familiar with XOM! I specifically want to know if and how you can do this kind of streaming with that library. (This is related to my question about the best dom4j replacement where XOM is a strong contender.)

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  • gcc/g++: error when compiling large file

    - by Alexander
    Hi, I have a auto-generated C++ source file, around 40 MB in size. It largely consists of push_back commands for some vectors and string constants that shall be pushed. When I try to compile this file, g++ exits and says that it couldn't reserve enough virtual memory (around 3 GB). Googling this problem, I found that using the command line switches --param ggc-min-expand=0 --param ggc-min-heapsize=4096 may solve the problem. They, however, only seem to work when optimization is turned on. 1) Is this really the solution that I am looking for? 2) Or is there a faster, better (compiling takes ages with these options acitvated) way to do this? Best wishes, Alexander Update: Thanks for all the good ideas. I tried most of them. Using an array instead of several push_back() operations reduced memory usage, but as the file that I was trying to compile was so big, it still crashed, only later. In a way, this behaviour is really interesting, as there is not much to optimize in such a setting -- what does the GCC do behind the scenes that costs so much memory? (I compiled with deactivating all optimizations as well and got the same results) The solution that I switched to now is reading in the original data from a binary object file that I created from the original file using objcopy. This is what I originally did not want to do, because creating the data structures in a higher-level language (in this case Perl) was more convenient than having to do this in C++. However, getting this running under Win32 was more complicated than expected. objcopy seems to generate files in the ELF format, and it seems that some of the problems I had disappeared when I manually set the output format to pe-i386. The symbols in the object file are by standard named after the file name, e.g. converting the file inbuilt_training_data.bin would result in these two symbols: binary_inbuilt_training_data_bin_start and binary_inbuilt_training_data_bin_end. I found some tutorials on the web which claim that these symbols should be declared as extern char _binary_inbuilt_training_data_bin_start;, but this does not seem to be right -- only extern char binary_inbuilt_training_data_bin_start; worked for me.

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  • Buy or Build for web deployment?

    - by Cannonade
    I have been evaluating the wide range of installation and web deployment solutions available for Windows applications. I will just clarify here (without too much detail, these tools have been covered in other questions) my understanding of the options: NSIS - Free tool that generates setup executables. Small binary. Specialized, sometimes obtuse, scripting language. Inno Setup - Free tools for setup executables. Various binary compression schemes. Pascal scripting engine. WIX - Free toolset to generate MSI binaries. XML definitions language. WIX ClickThrough - Additional tools for packaging, web download and auto update detection (now part of WIX core). InstallShield - Commercial development environment for installation packaging. Generates MSI binaries. C-like InstallScript language. Wise - Commercial development environment for installation packaging. Generates MSI binaries. ClickOnce - Visual Studio supported framework for publishing applications to a webserver, with automatic detection of updates. No support for custom installation requirements (INI files, registry etc ...). Packages setup as an MSI binary. Install Aware - Commercial development environment for installation. Generates MSI binaries. Automatic Update framwork (Web Update). If I have missed any, please let me know. And found some useful discussions of these technologies on StackOverflow: Best Simple Install System Best choice for Windows installers Alternatives to ClickOnce I have worked with a few of these solutions, as well as a handful of proprietary internal installation solutions. They are mostly concerned with packing installations and providing a framework for developers to access the run time environment. With the growing requirement for web deployment and automatic software updates, I expected to find more of a consensus among developers on a framework for web delivery of software and subsequent updates, I haven't really found that consensus. There are certainly solutions available (ClickOnce, ClickThrough, InstallShield Update Service), but they each have considerable limitations (please correct me if I mis-represent any of these). I would be interested in a framework that provided some of the following: Third party hosting/management of updates. Access to client environment (INI files, registry, etc..). User registration/activation. Feedback/Error reporting This is leaving me with the strong impression that the best way to approach the web deployment problem is through a custom built proprietary solution (possibly leveraging existing installer packaging). I have seen this sort of solution work well for a number of successful applications: FileZilla - HTTP request to update.filezilla-project.org to check for updates, downloads an NSIS binary (I think) and then shuts down to run the install.

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  • Multiple Cookie Generation Issue

    - by Shannon
    Hi all, jQuery newbie here. I need to be able to set multiple cookies within the code without have to change out this variable each and every time. Is there any way to make this code generate unique cookies for different pages? As it is now, I'm having to rename that variable for each page that the jQuery animations exist on. (sbbcookiename) Background on the issue: We are having issues with the sliders not autoplaying once one has already been triggered, due to it the cookie having been cached. Thanks for your help. (function(){ jQuery.noConflict(); var _TIMEOUT= 1000, initTimer= 0, sbLoaded= false, _re= null ; initTimer= setTimeout(initSlider, _TIMEOUT); jQuery(document).ready(initSlider); function initSlider(){ if(sbLoaded) return; if (jQuery('#campaign_name').length > 0) { var sbbcookiename = jQuery('#campaign_name').attr('class'); } else { var sbbcookiename = "slider728x90"; } var slideTimeout //timer ,sbTrigger = jQuery('#slidebartrigger') //convenience ,sbFirstSlide = (document.cookie.indexOf(sbbcookiename) == -1) //check cookie for 'already seen today' ; clearTimeout(initTimer); sbLoaded= true; function toggleSlideboxes(){ if(slideTimeout) clearTimeout(slideTimeout); var isDown = sbTrigger.is('.closeSlide'); jQuery('#slidebar')['slide' + (isDown ? 'Up' : 'Down')]((isDown ? 1000 : 1000), function(){ if(sbFirstSlide){ //if 'first time today' then clear for click-to-replay sbTrigger.removeClass('firstSlide'); sbFirstSlide = false; } sbTrigger[(isDown ? 'remove' : 'add') + 'Class']('closeSlide').one('click', toggleSlideboxes); if(!isDown) slideTimeout = setTimeout(toggleSlideboxes, 4000); }); } if(sbFirstSlide){ //not seen yet today so set a cookie for expire tomorrow, then toggle the slide boxes... var oneDay = new Date(); oneDay.setUTCDate(oneDay.getUTCDate()+1); oneDay.setUTCHours(0, 0, 0, 0); //set to literally day-by-day, rather than 24 hours document.cookie=sbbcookiename+"=true;path=/;expires="+oneDay.toUTCString(); toggleSlideboxes(); }else{ //already seen today so show the trigger and set a click event on it... sbTrigger.removeClass('firstSlide').one('click', toggleSlideboxes); } } })();

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  • deleted gen folder, eclipse isn't generating it now :(

    - by LuxuryMode
    I accidentally deleted my gen folder and now, predictably, my resources are all messed up. I just created a gen folder myself and tried to project clean - that didn't work. Tried right-clicking project and going to android tools fix project properties - didn't work. Tried unchecking build automatically...didn't work. cleaned, closed project, closed eclipse, restarted, etc, etc. Nothing is working and I keep seeing this error: gen already exists but is not a source folder. Convert to a source folder or rename it. EDIT - OK was able to generate R.java, but now I'm getting crazy stuff in the console: [2011-06-14 17:06:11 - fastapp] Conversion to Dalvik format failed with error 1 [2011-06-14 17:06:42 - fastapp] Dx trouble processing "java/awt/font/NumericShaper.class": Ill-advised or mistaken usage of a core class (java.* or javax.*) when not building a core library. This is often due to inadvertently including a core library file in your application's project, when using an IDE (such as Eclipse). If you are sure you're not intentionally defining a core class, then this is the most likely explanation of what's going on. However, you might actually be trying to define a class in a core namespace, the source of which you may have taken, for example, from a non-Android virtual machine project. This will most assuredly not work. At a minimum, it jeopardizes the compatibility of your app with future versions of the platform. It is also often of questionable legality. If you really intend to build a core library -- which is only appropriate as part of creating a full virtual machine distribution, as opposed to compiling an application -- then use the "--core-library" option to suppress this error message. If you go ahead and use "--core-library" but are in fact building an application, then be forewarned that your application will still fail to build or run, at some point. Please be prepared for angry customers who find, for example, that your application ceases to function once they upgrade their operating system. You will be to blame for this problem. If you are legitimately using some code that happens to be in a core package, then the easiest safe alternative you have is to repackage that code. That is, move the classes in question into your own package namespace. This means that they will never be in conflict with core system classes. JarJar is a tool that may help you in this endeavor. If you find that you cannot do this, then that is an indication that the path you are on will ultimately lead to pain, suffering, grief, and lamentation. [2011-06-14 17:06:42 - fastapp] Dx 1 error; aborting [2011-06-14 17:06:42 - fastapp] Conversion to Dalvik format failed with error 1 And eclipse can't resolve the import of my resources import com.me.fastapp.R;

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  • SIGSEGV problem

    - by sickmate
    I'm designing a protocol (in C) to implement the layered OSI network structure, using cnet (http://www.csse.uwa.edu.au/cnet/). I'm getting a SIGSEGV error at runtime, however cnet compiles my source code files itself (I can't compile it through gcc) so I can't easily use any debugging tools such as gdb to find the error. Here's the structures used, and the code in question: typedef struct { char *data; } DATA; typedef struct { CnetAddr src_addr; CnetAddr dest_addr; PACKET_TYPE type; DATA data; } Packet; typedef struct { int length; int checksum; Packet datagram; } Frame; static void keyboard(CnetEvent ev, CnetTimerID timer, CnetData data) { char line[80]; int length; length = sizeof(line); CHECK(CNET_read_keyboard((void *)line, (unsigned int *)&length)); // Reads input from keyboard if(length > 1) { /* not just a blank line */ printf("\tsending %d bytes - \"%s\"\n", length, line); application_downto_transport(1, line, &length); } } void application_downto_transport(int link, char *msg, int *length) { transport_downto_network(link, msg, length); } void transport_downto_network(int link, char *msg, int *length) { Packet *p; DATA *d; p = (Packet *)malloc(sizeof(Packet)); d = (DATA *)malloc(sizeof(DATA)); d->data = msg; p->data = *d; network_downto_datalink(link, (void *)p, length); } void network_downto_datalink(int link, Packet *p, int *length) { Frame *f; // Encapsulate datagram and checksum into a Frame. f = (Frame *)malloc(sizeof(Frame)); f->checksum = CNET_crc32((unsigned char *)(p->data).data, *length); // Generate 32-bit CRC for the data. f->datagram = *p; f->length = sizeof(f); //Pass Frame to the CNET physical layer to send Frame to the require link. CHECK(CNET_write_physical(link, (void *)f, (size_t *)f->length)); free(p->data); free(p); free(f); } I managed to find that the line: CHECK(CNET_write_physical(link, (void *)f, (size_t *)f-length)); is causing the segfault but I can't work out why. Any help is greatly appreciated.

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  • Parallel For Loop - Problems when adding to a List - Possible .Net Bugs

    - by Kevin Crowell
    I am having some issues involving Parallel for loops and adding to a List. The problem is, the same code may generate different output at different times. I have set up some test code below. In this code, I create a List of 10,000 int values. 1/10th of the values will be 0, 1/10th of the values will be 1, all the way up to 1/10th of the values being 9. After setting up this List, I setup a Parallel for loop that iterates through the list. If the current number is 0, I add a value to a new List. After the Parallel for loop completes, I output the size of the list. The size should always be 1,000. Most of the time, the correct answer is given. However, I have seen 3 possible incorrect outcomes occur: The size of the list is less than 1,000 An IndexOutOfRangeException occurs @ doubleList.Add(0.0); An ArgumentException occurs @ doubleList.Add(0.0); The message for the ArgumentException given was: Destination array was not long enough. Check destIndex and length, and the array's lower bounds. What could be causing the errors? Is this a .Net bug? Is there something I can do to prevent this from happening? Please try the code for yourself. If you do not get an error, try it a few times. Please also note that you probably will not see any errors using a single-core machine. using System; using System.Collections.Generic; using System.Threading.Tasks; namespace ParallelTest { class Program { static void Main(string[] args) { List<int> intList = new List<int>(); List<double> doubleList = new List<double>(); for (int i = 0; i < 250; i++) { intList.Clear(); doubleList.Clear(); for (int j = 0; j < 10000; j++) { intList.Add(j % 10); } Parallel.For(0, intList.Count, j => { if (intList[j] == 0) { doubleList.Add(0.0); } }); if (doubleList.Count != 1000) { Console.WriteLine("On iteration " + i + ": List size = " + doubleList.Count); } } Console.WriteLine("\nPress any key to exit."); Console.ReadKey(); } } }

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  • Parallel For Loop - Problems when adding to a List

    - by Kevin Crowell
    I am having some issues involving Parallel for loops and adding to a List. The problem is, the same code may generate different output at different times. I have set up some test code below. In this code, I create a List of 10,000 int values. 1/10th of the values will be 0, 1/10th of the values will be 1, all the way up to 1/10th of the values being 9. After setting up this List, I setup a Parallel for loop that iterates through the list. If the current number is 0, I add a value to a new List. After the Parallel for loop completes, I output the size of the list. The size should always be 1,000. Most of the time, the correct answer is given. However, I have seen 3 possible incorrect outcomes occur: The size of the list is less than 1,000 An IndexOutOfRangeException occurs @ doubleList.Add(0.0); An ArgumentException occurs @ doubleList.Add(0.0); The message for the ArgumentException given was: Destination array was not long enough. Check destIndex and length, and the array's lower bounds. What could be causing the errors? Is this a .Net bug? Is there something I can do to prevent this from happening? Please try the code for yourself. If you do not get an error, try it a few times. Please also note that you probably will not see any errors using a single-core machine. using System; using System.Collections.Generic; using System.Threading.Tasks; namespace ParallelTest { class Program { static void Main(string[] args) { List<int> intList = new List<int>(); List<double> doubleList = new List<double>(); for (int i = 0; i < 250; i++) { intList.Clear(); doubleList.Clear(); for (int j = 0; j < 10000; j++) { intList.Add(j % 10); } Parallel.For(0, intList.Count, j => { if (intList[j] == 0) { doubleList.Add(0.0); } }); if (doubleList.Count != 1000) { Console.WriteLine("On iteration " + i + ": List size = " + doubleList.Count); } } Console.WriteLine("\nPress any key to exit."); Console.ReadKey(); } } }

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