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  • Non RBAC User Roles and Permissions System: a role with properties

    - by micha12
    We are currently designing a User Roles and Permissions System in our web application (ASP.NET), and it seems that we have several cases that do no fit within the classical Role-Based Access Control (RBAC). I will post several questions, each devoted to a particular case. This is my second question (the first question is here: http://stackoverflow.com/questions/2839797/non-rbac-user-roles-and-permissions-system-checking-the-users-city). We have the following case: we need to implement a Manager role in our web application. However, a Manager can belong to one or several companies (within a big group of companies for which we are creating this web app). Say, there can be “Manager of companies A and B”, “Manager of company C”, etc. Depending on the companies that the Manager belongs, he has access to certain operations: for example, he can communicate with clients only of those companies that he belongs to. That is, “Manager of companies A and B” can only have contacts with clients of companies A and B, and not with those of company C. He can also view clients’ details pages of companies A and B and not of C, etc. It seems that this case falls within the RBAC. However, this is not really the case. We will need to create a ManagerRole class that will have a Companies property – that is, this will not be just a role as a collection of permissions (like in the classical RBAC), but a role with properties! This was just one example of a role having properties. There will be others: for example, an Administrator role that will also belong to a number of companies and will also have other custom properties. This means that we will a hierarchy or roles classes: class Role – base class class ManagerRole : Role List Companies class AdministratorRole : Role List Companies Other properties We investigated pure RBAC and its implementation in several systems, and found no systems featuring a hierarchy or roles, each having custom properties. In RBAC, roles are just collections of permissions. We could model our cases using permission with properties, like ManagerPermission, AdministratorPermission, but this has a lot of drawbacks, the main being that we will not be able to assign a role like “Manager of Companies A and B” to a user directly, but will have to create a role containing a ManagerPermission for companies A and B… Moreover, a "Manager" seems to be rather a "role" (position in the company) rather than a "permission" from the linguistic point of view. Would be grateful for any ideas on this subject, as well as any experience in this field! Thank you.

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  • How to maximize http.sys file upload performance

    - by anelson
    I'm building a tool that transfers very large streaming data sets (possibly on the order of terabytes in a single stream; routinely in the tens of gigabytes) from one server to another. The client portion of the tool will read blocks from the source disk, and send them over the network. The server side will read these blocks off the network and write them to a file on the server disk. Right now I'm trying to decide which transport to use. Options are raw TCP, and HTTP. I really, REALLY want to be able to use HTTP. The HttpListener (or WCF if I want to go that route) make it easy to plug in to the HTTP Server API (http.sys), and I can get things like authentication and SSL for free. The problem right now is performance. I wrote a simple test harness that sends 128K blocks of NULL bytes using the BeginWrite/EndWrite async I/O idiom, with async BeginRead/EndRead on the server side. I've modified this test harness so I can do this with either HTTP PUT operations via HttpWebRequest/HttpListener, or plain old socket writes using TcpClient/TcpListener. To rule out issues with network cards or network pathways, both the client and server are on one machine and communicate over localhost. On my 12-core Windows 2008 R2 test server, the TCP version of this test harness can push bytes at 450MB/s, with minimal CPU usage. On the same box, the HTTP version of the test harness runs between 130MB/s and 200MB/s depending upon how I tweak it. In both cases CPU usage is low, and the vast majority of what CPU usage there is is kernel time, so I'm pretty sure my usage of C# and the .NET runtime is not the bottleneck. The box has two 6-core Xeon X5650 processors, 24GB of single-ranked DDR3 RAM, and is used exclusively by me for my own performance testing. I already know about HTTP client tweaks like ServicePointManager.MaxServicePointIdleTime, ServicePointManager.DefaultConnectionLimit, ServicePointManager.Expect100Continue, and HttpWebRequest.AllowWriteStreamBuffering. Does anyone have any ideas for how I can get HTTP.sys performance beyond 200MB/s? Has anyone seen it perform this well on any environment?

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  • Sql Server Compact 2005 on Visual Studio 2008

    - by Tim
    I'm working on a Windows Forms application that interacts with a Sql Compact database file created by SQL Server 2005. This application was originally developed in Visual Studio 2005 but was recently converted to a Visual Studio 2008 solution. In regards to Sql Compact, we made sure the references were all still set to the assemblies that handle the 2005 version of Sql Compact rather than Sql Compact 3.5. Having done this, the application still runs just as it should - it will still interact with the Compact database, perform synchronization operations, etc. However, I just discovered today that Visual Studio tools such as the DataSet Designer do not play well with a Sql Compact database file of an older version than 3.5. If I go to the New Connection... wizard, the only Sql Compact Data Source / Data Provider are for Sql Compact 3.5. I assume that Visual Studio 2008 just doesn't include the data provider for the older version of Sql Compact by default. Is there a way you can add the old version of Sql Compact to the list of "Data Sources" for the connection wizard? To see exactly what I'm referring to, click on the Tools menu of Visual Studio 2008 and click Connect to Database... In the window that comes up, click Change... next to the Data source setting. From this dialog there is no way I can select the earlier version of Sql Compact - only 3.5 is available. Maybe I need to add an assembly reference somewhere? Or copy some file(s) from my Visual Studio 2005 directory over to 2008? I would think there would have to be a way for Visual Studio 2008 to be able to interact with a Sql Compact database from Sql Server 2005. To provide one more bit of detail, I discovered this problem when I went to my DataSet, right-clicked and tried to add a TableAdapter. The first screen that comes up says, "Choose Your Data Connection". If I leave it set to the Sql Compact connection that we've always used, I now get the following error when clicking the Next button: Failed to open a connection to the database "The selected database was created with an earlier version of SQL Server Compact and needs to be upgraded to SQL Server Compact 3.5 before the connection can be opened or tested. Upgrade the database by creating a new data connection and completing the Add Connection dialog box." Check the connection and try again. The only problem here is that we still use Sql Server 2005, and if my understanding is correct, it does not produce subscription files that are compatible with Sql Compact 3.5. If I am wrong in this assumption, please correct me. Any help you can provide is greatly appreciated. Thank you.

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  • TcpListener is queuing connections faster than I can clear them

    - by Matthew Brindley
    As I understand it, TcpListener will queue connections once you call Start(). Each time you call AcceptTcpClient (or BeginAcceptTcpClient), it will dequeue one item from the queue. If we load test our TcpListener app by sending 1,000 connections to it at once, the queue builds far faster than we can clear it, leading (eventually) to timeouts from the client because it didn't get a response because its connection was still in the queue. However, the server doesn't appear to be under much pressure, our app isn't consuming much CPU time and the other monitored resources on the machine aren't breaking a sweat. It feels like we're not running efficiently enough right now. We're calling BeginAcceptTcpListener and then immediately handing over to a ThreadPool thread to actually do the work, then calling BeginAcceptTcpClient again. The work involved doesn't seem to put any pressure on the machine, it's basically just a 3 second sleep followed by a dictionary lookup and then a 100 byte write to the TcpClient's stream. Here's the TcpListener code we're using: // Thread signal. private static ManualResetEvent tcpClientConnected = new ManualResetEvent(false); public void DoBeginAcceptTcpClient(TcpListener listener) { // Set the event to nonsignaled state. tcpClientConnected.Reset(); listener.BeginAcceptTcpClient( new AsyncCallback(DoAcceptTcpClientCallback), listener); // Wait for signal tcpClientConnected.WaitOne(); } public void DoAcceptTcpClientCallback(IAsyncResult ar) { // Get the listener that handles the client request, and the TcpClient TcpListener listener = (TcpListener)ar.AsyncState; TcpClient client = listener.EndAcceptTcpClient(ar); if (inProduction) ThreadPool.QueueUserWorkItem(state => HandleTcpRequest(client, serverCertificate)); // With SSL else ThreadPool.QueueUserWorkItem(state => HandleTcpRequest(client)); // Without SSL // Signal the calling thread to continue. tcpClientConnected.Set(); } public void Start() { currentHandledRequests = 0; tcpListener = new TcpListener(IPAddress.Any, 10000); try { tcpListener.Start(); while (true) DoBeginAcceptTcpClient(tcpListener); } catch (SocketException) { // The TcpListener is shutting down, exit gracefully CheckBuffer(); return; } } I'm assuming the answer will be related to using Sockets instead of TcpListener, or at least using TcpListener.AcceptSocket, but I wondered how we'd go about doing that? One idea we had was to call AcceptTcpClient and immediately Enqueue the TcpClient into one of multiple Queue<TcpClient> objects. That way, we could poll those queues on separate threads (one queue per thread), without running into monitors that might block the thread while waiting for other Dequeue operations. Each queue thread could then use ThreadPool.QueueUserWorkItem to have the work done in a ThreadPool thread and then move onto dequeuing the next TcpClient in its queue. Would you recommend this approach, or is our problem that we're using TcpListener and no amount of rapid dequeueing is going to fix that?

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  • How to use objetcs as modules/functors in Scala?

    - by Jeff
    Hi. I want to use object instances as modules/functors, more or less as shown below: abstract class Lattice[E] extends Set[E] { val minimum: E val maximum: E def meet(x: E, y: E): E def join(x: E, y: E): E def neg(x: E): E } class Calculus[E](val lat: Lattice[E]) { abstract class Expr case class Var(name: String) extends Expr {...} case class Val(value: E) extends Expr {...} case class Neg(e1: Expr) extends Expr {...} case class Cnj(e1: Expr, e2: Expr) extends Expr {...} case class Dsj(e1: Expr, e2: Expr) extends Expr {...} } So that I can create a different calculus instance for each lattice (the operations I will perform need the information of which are the maximum and minimum values of the lattice). I want to be able to mix expressions of the same calculus but not be allowed to mix expressions of different ones. So far, so good. I can create my calculus instances, but problem is that I can not write functions in other classes that manipulate them. For example, I am trying to create a parser to read expressions from a file and return them; I also was trying to write an random expression generator to use in my tests with ScalaCheck. Turns out that every time a function generates an Expr object I can't use it outside the function. Even if I create the Calculus instance and pass it as an argument to the function that will in turn generate the Expr objects, the return of the function is not recognized as being of the same type of the objects created outside the function. Maybe my english is not clear enough, let me try a toy example of what I would like to do (not the real ScalaCheck generator, but close enough). def genRndExpr[E](c: Calculus[E], level: Int): Calculus[E]#Expr = { if (level > MAX_LEVEL) { val select = util.Random.nextInt(2) select match { case 0 => genRndVar(c) case 1 => genRndVal(c) } } else { val select = util.Random.nextInt(3) select match { case 0 => new c.Neg(genRndExpr(c, level+1)) case 1 => new c.Dsj(genRndExpr(c, level+1), genRndExpr(c, level+1)) case 2 => new c.Cnj(genRndExpr(c, level+1), genRndExpr(c, level+1)) } } } Now, if I try to compile the above code I get lots of error: type mismatch; found : plg.mvfml.Calculus[E]#Expr required: c.Expr case 0 = new c.Neg(genRndExpr(c, level+1)) And the same happens if I try to do something like: val boolCalc = new Calculus(Bool) val e1: boolCalc.Expr = genRndExpr(boolCalc) Please note that the generator itself is not of concern, but I will need to do similar things (i.e. create and manipulate calculus instance expressions) a lot on the rest of the system. Am I doing something wrong? Is it possible to do what I want to do? Help on this matter is highly needed and appreciated. Thanks a lot in advance.

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  • Java Hardware Acceleration

    - by Freezerburn
    I have been spending some time looking into the hardware acceleration features of Java, and I am still a bit confused as none of the sites that I found online directly and clearly answered some of the questions I have. So here are the questions I have for hardware acceleration in Java: 1) In Eclipse version 3.6.0, with the most recent Java update for Mac OS X (1.6u10 I think), is hardware acceleration enabled by default? I read somewhere that someCanvas.getGraphicsConfiguration().getBufferCapabilities().isPageFlipping() is supposed to give an indication of whether or not hardware acceleration is enabled, and my program reports back true when that is run on my main Canvas instance for drawing to. If my hardware acceleration is not enabled now, or by default, what would I have to do to enable it? 2) I have seen a couple articles here and there about the difference between a BufferedImage and VolatileImage, mainly saying that VolatileImage is the hardware accelerated image and is stored in VRAM for fast copy-from operations. However, I have also found some instances where BufferedImage is said to be hardware accelerated as well. Is BufferedImage hardware accelerated as well in my environment? What would be the advantage of using a VolatileImage if both types are hardware accelerated? My main assumption for the advantage of having a VolatileImage in the case of both having acceleration is that VolatileImage is able to detect when its VRAM has been dumped. But if BufferedImage also support acceleration now, would it not have the same kind of detection built into it as well, just hidden from the user, in case that the memory is dumped? 3) Is there any advantage to using someGraphicsConfiguration.getCompatibleImage/getCompatibleVolatileImage() as opposed to ImageIO.read() In a tutorial I have been reading for some general concepts about setting up the rendering window properly (tutorial) it uses the getCompatibleImage method, which I believe returns a BufferedImage, to get their "hardware accelerated" images for fast drawing, which ties into question 2 about if it is hardware accelerated. 4) This is less hardware acceleration, but it is something I have been curious about: do I need to order which graphics get drawn? I know that when using OpenGL via C/C++ it is best to make sure that the same graphic is drawn in all the locations it needs to be drawn at once to reduce the number of times the current texture needs to be switch. From what I have read, it seems as if Java will take care of this for me and make sure things are drawn in the most optimal fashion, but again, nothing has ever said anything like this clearly. 5) What AWT/Swing classes support hardware acceleration, and which ones should be used? I am currently using a class that extends JFrame to create a window, and adding a Canvas to it from which I create a BufferStrategy. Is this good practice, or is there some other type of way I should be implementing this? Thank you very much for your time, and I hope I provided clear questions and enough information for you to answer my several questions.

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  • How to use CFNetwork to get byte array from sockets?

    - by Vic
    Hi, I'm working in a project for the iPad, it is a small program and I need it to communicate with another software that runs on windows and act like a server; so the application that I'm creating for the iPad will be the client. I'm using CFNetwork to do sockets communication, this is the way I'm establishing the connection: char ip[] = "192.168.0.244"; NSString *ipAddress = [[NSString alloc] initWithCString:ip]; /* Build our socket context; this ties an instance of self to the socket */ CFSocketContext CTX = { 0, self, NULL, NULL, NULL }; /* Create the server socket as a TCP IPv4 socket and set a callback */ /* for calls to the socket's lower-level connect() function */ TCPClient = CFSocketCreate(NULL, PF_INET, SOCK_STREAM, IPPROTO_TCP, kCFSocketDataCallBack, (CFSocketCallBack)ConnectCallBack, &CTX); if (TCPClient == NULL) return; /* Set the port and address we want to listen on */ struct sockaddr_in addr; memset(&addr, 0, sizeof(addr)); addr.sin_len = sizeof(addr); addr.sin_family = AF_INET; addr.sin_port = htons(PORT); addr.sin_addr.s_addr = inet_addr([ipAddress UTF8String]); CFDataRef connectAddr = CFDataCreate(NULL, (unsigned char *)&addr, sizeof(addr)); CFSocketConnectToAddress(TCPClient, connectAddr, -1); CFRunLoopSourceRef sourceRef = CFSocketCreateRunLoopSource(kCFAllocatorDefault, TCPClient, 0); CFRunLoopAddSource(CFRunLoopGetCurrent(), sourceRef, kCFRunLoopCommonModes); CFRelease(sourceRef); CFRunLoopRun(); And this is the way I sent the data, which basically is a byte array /* The native socket, used for various operations */ // TCPClient is a CFSocketRef member variable CFSocketNativeHandle sock = CFSocketGetNative(TCPClient); Byte byteData[3]; byteData[0] = 0; byteData[1] = 4; byteData[2] = 0; send(sock, byteData, strlen(byteData)+1, 0); Finally, as you may have noticed, when I create the server socket, I registered a callback for the kCFSocketDataCallBack type, this is the code. void ConnectCallBack(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void *data, void *info) { // SocketsViewController is the class that contains all the methods SocketsViewController *obj = (SocketsViewController*)info; UInt8 *unsignedData = (UInt8 *) CFDataGetBytePtr(data); char *value = (char*)unsignedData; NSString *text = [[NSString alloc]initWithCString:value length:strlen(value)]; [obj writeToTextView:text]; [text release]; } Actually, this callback is being invoked in my code, the problem is that I don't know how can I get the data that the windows client sent me, I'm expecting to receive an array of bytes, but I don't know how can I get those bytes from the data param. If anyone can help me to find a way to do this, or maybe me point me to another way to get the data from the server in my client application I would really appreciate it. Thanks.

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  • Am I using EJBs properly?

    - by kgrad
    I am using a JEE6 stack including JPA 2.0, JSF 2.0, EJB 3.1 etc. The way my architecture is setup is the following: I have JPA annotated DAOs using hibernate as my JPA provider. I have JSF Managed beans which correspond to my facelet/xhtml pages. I have EJBs that handle all of my database requests. My XHTML pages have JSF EL which make calls to my Managed beans. My managed beans contain references to my DAO entities which are managed by EJBs. For example, I have a user entity which is mapped to a db table. I have a user EJB which handles all CRUD operations that return Users. I have a page that edits a user. The highlevel workflow would be: navigate to user edit page - EL calls a method located in the managed bean that loads a user. The method calls userEJB.loadUser(user) from the EJB to get the user from the database. The user is edited and submit - a function is called in the managed bean which calls a function in the EJB to save the user. etc. I am running into issues accessing my data within my JSF pages using EJBs. I am having a lot of problems with lazy initialization errors, which I believe is due to how I have set things up. For example, I have a Client entity that has a List of users which are lazily loaded. In order to get a client I call a method in my EJB which goes to the database, finds a client and returns it. Later on i wish to access this clients list of users, in order to do so i have to go back to the EJB by calling some sort of method in order to load those users (since they are lazily loaded). This means that I have to create a method such as public List<User> getUserListByClient(Client c) { c = em.merge(c); return c.getUserList(); } The only purpose of this method is to load the users (and I'm not even positive this approach is good or works). If i was doing session management myself, I would like just leave the session open for the entire request and access the property directly, this would be fine as the session would be open anyway, there seems to be this one extra layer of indirection in EJBs which is making things difficult for me. I do like EJBs as I like the fact that they are controlled by the container, pooled, offer transaction management for free etc. However, I get the feeling that I am using them incorrectly, or I have set up my JSF app incorrectly. Any feedback would be greatly appreciated. thanks,

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  • VS2008: File creation fails randomly in unit testing?

    - by Tim
    I'm working on implementing a reasonably simple XML serializer/deserializer (log file parser) application in C# .NET with VS 2008. I have about 50 unit tests right now for various parts of the code (mostly for the various serialization operations), and some of them seem to be failing mostly at random when they deal with file I/O. The way the tests are structured is that in the test setup method, I create a new empty file at a certain predetermined location, and close the stream I get back. Then I run some basic tests on the file (varying by what exactly is under test). In the cleanup method, I delete the file again. A large portion (usually 30 or more, though the number varies run to run) of my unit tests will fail at the initialize method, claiming they can't access the file I'm trying to create. I can't pin down the exact reason, since a test that will work one run fails the next; they all succeed when run individually. What's the problem here? Why can't I access this file across multiple unit tests? Relevant methods for a unit test that will fail some of the time: [TestInitialize()] public void LogFileTestInitialize() { this.testFolder = System.Environment.GetFolderPath( System.Environment.SpecialFolder.LocalApplicationData ); this.testPath = this.testFolder + "\\empty.lfp"; System.IO.File.Create(this.testPath); } [TestMethod()] public void LogFileConstructorTest() { string filePath = this.testPath; LogFile target = new LogFile(filePath); Assert.AreNotEqual(null, target); Assert.AreEqual(this.testPath, target.filePath); Assert.AreEqual("empty.lfp", target.fileName); Assert.AreEqual(this.testFolder + "\\empty.lfp.lfpdat", target.metaPath); } [TestCleanup()] public void LogFileTestCleanup() { System.IO.File.Delete(this.testPath); } And the LogFile() constructor: public LogFile(String filePath) { this.entries = new List<Entry>(); this.filePath = filePath; this.metaPath = filePath + ".lfpdat"; this.fileName = filePath.Substring(filePath.LastIndexOf("\\") + 1); } The precise error message: Initialization method LogFileParserTester.LogFileTest.LogFileTestInitialize threw exception. System.IO.IOException: System.IO.IOException: The process cannot access the file 'C:\Users\<user>\AppData\Local\empty.lfp' because it is being used by another process..

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  • SQL Server 2008 Filestream Impersonation Access Denied error

    - by Adi
    I've been trying to upload a file to the database using SQL SERVER 2008 Filestream and Impersonation technique to save the file in the file system, but i keep getting Access Denied error; even though i've set the permissions for the impersonating user to the Filestream folder(C:\SQLFILESTREAM\Dev_DB). when i debugged the code, i found the server return a unc path(\Server_Name\MSSQLSERVER\v1\Dev_LMDB\dbo\FileData\File_Data\13C39AB1-8B91-4F5A-81A1-940B58504C17), which was not accessible through windows explorer. I've my web application hosted on local maching(Windows 7). SQL Server is located on a remote server(Windows Server 2008 R2). Sql authentication was used to call the stored procedure. Following is the code i've used to do the above operations. SqlCommand sqlCmd = new SqlCommand("AddFile"); sqlCmd.CommandType = CommandType.StoredProcedure; sqlCmd.Parameters.Add("@File_Name", SqlDbType.VarChar, 512).Value = filename; sqlCmd.Parameters.Add("@File_Type", SqlDbType.VarChar, 5).Value = Path.GetExtension(filename); sqlCmd.Parameters.Add("@Username", SqlDbType.VarChar, 20).Value = username; sqlCmd.Parameters.Add("@Output_File_Path", SqlDbType.VarChar, -1).Direction = ParameterDirection.Output; DAManager PDAM = new DAManager(DAManager.getConnectionString()); using (SqlConnection connection = (SqlConnection)PDAM.CreateConnection()) { connection.Open(); SqlTransaction transaction = connection.BeginTransaction(); WindowsImpersonationContext wImpersonationCtx; NetworkSecurity ns = null; try { PDAM.ExecuteNonQuery(sqlCmd, transaction); string filepath = sqlCmd.Parameters["@Output_File_Path"].Value.ToString(); sqlCmd = new SqlCommand("SELECT GET_FILESTREAM_TRANSACTION_CONTEXT()"); sqlCmd.CommandType = CommandType.Text; byte[] Context = (byte[])PDAM.ExecuteScalar(sqlCmd, transaction); byte[] buffer = new byte[4096]; int bytedRead; ns = new NetworkSecurity(); wImpersonationCtx = ns.ImpersonateUser(IMP_Domain, IMP_Username, IMP_Password, LogonType.LOGON32_LOGON_INTERACTIVE, LogonProvider.LOGON32_PROVIDER_DEFAULT); SqlFileStream sfs = new SqlFileStream(filepath, Context, System.IO.FileAccess.Write); while ((bytedRead = inFS.Read(buffer, 0, buffer.Length)) != 0) { sfs.Write(buffer, 0, bytedRead); } sfs.Close(); transaction.Commit(); } catch (Exception ex) { transaction.Rollback(); } finally { sqlCmd.Dispose(); connection.Close(); connection.Dispose(); ns.undoImpersonation(); wImpersonationCtx = null; ns = null; } } Can someone help me with this issue. Reference Exception: Type : System.ComponentModel.Win32Exception, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 Message : Access is denied Source : System.Data Help link : NativeErrorCode : 5 ErrorCode : -2147467259 Data : System.Collections.ListDictionaryInternal TargetSite : Void OpenSqlFileStream(System.String, Byte[], System.IO.FileAccess, System.IO.FileOptions, Int64) Stack Trace : at System.Data.SqlTypes.SqlFileStream.OpenSqlFileStream(String path, Byte[] transactionContext, FileAccess access, FileOptions options, Int64 allocationSize) at System.Data.SqlTypes.SqlFileStream..ctor(String path, Byte[] transactionContext, FileAccess access, FileOptions options, Int64 allocationSize) at System.Data.SqlTypes.SqlFileStream..ctor(String path, Byte[] transactionContext, FileAccess access) Thanks

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  • Cube project doesn't work because of permissions

    - by sms
    I'm doing "Multidimensional Project" with MS SQL Server 2012 (Server Data Tools - Visual Studio 2010 Shell). I can't run (debug) it. If the data source's impersonation information is set to "use the service account", this error occures: Error 2 Internal error: The operation terminated unsuccessfully. 0 0 Error 3 OLE DB error: OLE DB or ODBC error: Login failed for user 'NT Service\MSSQLServerOLAPService'.; 28000. 0 0 Error 4 Errors in the high-level relational engine. A connection could not be made to the data source with the DataSourceID of 'Data Warehouse', Name of 'Data Warehouse'. 0 0 Error 5 Errors in the OLAP storage engine: An error occurred while the dimension, with the ID of 'Items', Name of 'Items' was being processed. 0 0 Error 6 Errors in the OLAP storage engine: An error occurred while the 'Id' attribute of the 'Items' dimension from the 'Warehouse_MultidimensionalProject_Cube' database was being processed. 0 0 Error 7 Server: The current operation was cancelled because another operation in the transaction failed. 0 0 I guessed that this account has no premissions but (1) I coudn't even add this account (it seems that it doesn't exist) and (2) how is that even possible for it to not have built-it poremissions? When I'm setting impersonation to "use the credentials of current user" (which is the owner of the data source, btw.), another error occures: Error 2 Internal error: The operation terminated unsuccessfully. 0 0 Error 3 The datasource, 'Data Warehouse', contains an ImpersonationMode that is not supported for processing operations. 0 0 Error 4 Errors in the high-level relational engine. A connection could not be made to the data source with the DataSourceID of 'Data Warehouse', Name of 'Data Warehouse'. 0 0 Error 5 Errors in the OLAP storage engine: An error occurred while the dimension, with the ID of 'Items', Name of 'Items' was being processed. 0 0 Error 6 Errors in the OLAP storage engine: An error occurred while the 'Id' attribute of the 'Items' dimension from the 'Warehouse_MultidimensionalProject_Cube' database was being processed. 0 0 Error 7 Server: The current operation was cancelled because another operation in the transaction failed. 0 0 Any help?

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  • What to do when you need more verbs in REST

    - by Richard Levasseur
    There is another similar question to mine, but the discussion veered away from the problem I'm encounting. Say I have a system that deals with expense reports (ER). You can create and edit them, add attachments, and approve/reject them. An expense report might look like this: GET /er/1 => {"title": "Trip to NY", "totalcost": "400 USD", "comments": [ "john: Please add the total cost", "mike: done, can you approve it now?" ], "approvals": [ {"john": "Pending"}, {"finance-group": "Pending"}] } That looks fine, right? Thats what an expense report document looks like. If you want to update it, you can do this: POST /er/1 {"title": "Trip to NY 2010"} If you want to approve it, you can do this: POST /er/1/approval {"approved": true} But, what if you want to update the report and approve it at the same time? How do we do that? If you only wanted to approve, then doing a POST to something like /er/1/approval makes sense. We could put a flag in the URL, POST /er/1?approve=1, and send the data changes as the body, but that flag doesn't seem RESTful. We could put special field to be submitted, too, but that seems a bit hacky, too. If we did that, then why not send up data with attributes like set_title or add_to_cost? We could create a new resource for updating and approving, but (1) I can't think of how to name it without verbs, and (2) it doesn't seem right to name a resource based on what actions can be done to it (what happens if we add more actions?) We could have an X-Approve: True|False header, but headers seem like the wrong tool for the job. It'd also be difficult to get set headers without using javascript in a browser. We could use a custom media-type, application/approve+yes, but that seems no better than creating a new resource. We could create a temporary "batch operations" url, /er/1/batch/A. The client then sends multiple requests, perhaps POST /er/1/batch/A to update, then POST /er/1/batch/A/approval to approve, then POST /er/1/batch/A/status to end the batch. On the backend, the server queues up all the batch requests somewhere, then processes them in the same backend-transaction when it receives the "end batch processing" request. The downside with this is, obviously, that it introduces a lot of complexity. So, what is a good, general way to solve the problem of performing multiple actions in a single request? General because its easy to imagine additional actions that might be done in the same request: Suppress or send notifications (to email, chat, another system, whatever) Override some validation (maximum cost, names of dinner attendees) Trigger backend workflow that doesn't have a representation in the document.

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  • Core-Data + AFNetworking + UI Updating (Responsiveness)

    - by Mustafa
    Here's the scenario: I'm writing a DownloadManager, that allows the user to download, pause, cancel, download all, and pause all. The DownloadManager is a singleton, and uses AFNetworking to download files. It has it's own private managed object context, so that user can freely use other parts of the application (by adding, editing, deleting) core-data objects. I have a core-data entity DownloadInfo that stores the download information i.e. fileURL, fileSize, bytesRead, etc. The DownloadManager updates the download progress in DownloadInfo (one for each file). I have a DownloadManagerViewController which uses NSFetchedResultsController to show the download status to the user. This download view controller is using the main managed object context. Now let's say that I have 20 files in the download queue. And let's say that only 3 concurrent downloads are allowed. The download manager should download the file, and show the download progress. Problem: The DownloadInfo objects are being updated by the DownloadManager at a very high rate. The DownloadManagerViewController (responsible for showing the download progress) is updating the list using NSFetchedResultsControllerDelegate methods. The result is that a lot is happening in the main queue and application has very poor responsiveness. How can I fix this? How can I make the application responsive, while showing the download progress? I don't know how else to communicate that the download status between DownloadManager and DownloadManagerViewController. Is there another/ a better way to do this? I don't want to use main managed object context in my DownloadManager, for reasons mentioned above. Note, that the DownloadManager is using AFNetworking which is handling the requests asynchronously, but eventually the DownloadInfo objects are updated in the main thread (as a result of the callback methods). Maybe there's a way to handle the downloads and status update operations in a background thread? but how? How will I communicate between the main thread and the background thread i.e. how will I tell the background thread to queue another file for download? Thanks.

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  • How Can I create different selectors for accepting new connection in java NIO

    - by Deepak
    I want to write java tcp socket programming using java NIO. Its working fine. But I am using the same selector for accepting reading from and writing to the clients. How Can I create different selectors for accepting new connection in java NIO, reading and writing. Is there any online help. Actually when I am busy in reading or writing my selector uses more iterator. So If more number of clients are connected then performance of accepting new coneection became slow. But I donot want the accepting clients to be slow // Create a selector and register two socket channels Selector selector = null; try { // Create the selector selector = Selector.open(); // Create two non-blocking sockets. This method is implemented in // e173 Creating a Non-Blocking Socket. SocketChannel sChannel1 = createSocketChannel("hostname.com", 80); SocketChannel sChannel2 = createSocketChannel("hostname.com", 80); // Register the channel with selector, listening for all events sChannel1.register(selector, sChannel1.validOps()); sChannel2.register(selector, sChannel1.validOps()); } catch (IOException e) { } // Wait for events while (true) { try { // Wait for an event selector.select(); } catch (IOException e) { // Handle error with selector break; } // Get list of selection keys with pending events Iterator it = selector.selectedKeys().iterator(); // Process each key at a time while (it.hasNext()) { // Get the selection key SelectionKey selKey = (SelectionKey)it.next(); // Remove it from the list to indicate that it is being processed it.remove(); try { processSelectionKey(selKey); } catch (IOException e) { // Handle error with channel and unregister selKey.cancel(); } } } public void processSelectionKey(SelectionKey selKey) throws IOException { // Since the ready operations are cumulative, // need to check readiness for each operation if (selKey.isValid() && selKey.isConnectable()) { // Get channel with connection request SocketChannel sChannel = (SocketChannel)selKey.channel(); boolean success = sChannel.finishConnect(); if (!success) { // An error occurred; handle it // Unregister the channel with this selector selKey.cancel(); } } if (selKey.isValid() && selKey.isReadable()) { // Get channel with bytes to read SocketChannel sChannel = (SocketChannel)selKey.channel(); // See e174 Reading from a SocketChannel } if (selKey.isValid() && selKey.isWritable()) { // Get channel that's ready for more bytes SocketChannel sChannel = (SocketChannel)selKey.channel(); } } Thanks Deepak

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  • What's the best way to do base36 arithmetic in perl?

    - by DVK
    What's the best way to do base36 arithmetic in Perl? To be more specific, I need to be able to do the following: Operate on positive N-digit numbers in base 36 (e.g. digits are 0-9 A-Z) N is finite, say 9 Provide basic arithmetic, at the very least the following 3: Addition (A+B) Subtraction (A-B) Whole division, e.g. floor(A/B). Strictly speaking, I don't really need a base10 conversion ability - the numbers will 100% of time be in base36. So I'm quite OK if the solution does NOT implement conversion from base36 back to base10 and vice versa. I don't much care whether the solution is brute-force "convert to base 10 and back" or converting to binary, or some more elegant approach "natively" performing baseN operations (as stated above, to/from base10 conversion is not a requirement). My only 3 considerations are: It fits the minimum specifications above It's "standard". Currently we're using and old homegrown module based on base10 conversion done by hand that is buggy and sucks. I'd much rather replace that with some commonly used CPAN solution instead of re-writing my own bicycle from scratch, but I'm perfectly capable of building it if no better standard possibility exists. It must be fast-ish (though not lightning fast). Something that takes 1 second to sum up 2 9-digit base36 numbers is worse than anything I can roll on my own :) P.S. Just to provide some context in case people decide to solve my XY problem for me in addition to answering the technical question above :) We have a fairly large tree (stored in DB as a bunch of edges), and we need to superimpose order on a subset of that tree. The tree dimentions are big both depth- and breadth- wise. The tree is VERY actively updated (inserts and deletes and branch moves). This is currently done by having a second table with 3 columns: parent_vertex, child_vertex, local_order, where local_order is an 9-character string built of A-Z0-9 (e.g. base 36 number). Additional considerations: It is required that the local order is unique per child (and obviously unique per parent), Any complete re-ordering of a parent is somewhat expensive, and thus the implementation is to try and assign - for a parent with X children - the orders which are somewhat evenly distributed between 0 and 36**10-1, so that almost no tree inserts result in a full re-ordering.

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  • Temporarily impersonate and enable privileges?

    - by Luke
    We maintain a DLL that does a lot of system-related things; traversing the file system, registry, etc. The callers of this DLL may or may not be using impersonation. In order to better support all possible scenarios I'm trying to modify it to be smarter. I'll use the example of deleting a file. Currently we just call DeleteFile(), and if that fails that's the end of that. I've come up with the following: BOOL TryReallyHardToDeleteFile(LPCTSTR lpFileName) { // 1. caller without privilege BOOL bSuccess = DeleteFile(lpFileName); DWORD dwError = GetLastError(); if(!bSuccess && dwError == ERROR_ACCESS_DENIED) { // failed with access denied; try with privilege DWORD dwOldRestorePrivilege = 0; BOOL bHasRestorePrivilege = SetPrivilege(SE_RESTORE_NAME, SE_PRIVILEGE_ENABLED, &dwOldRestorePrivilege); if(bHasRestorePrivilege) { // 2. caller with privilege bSuccess = DeleteFile(lpFileName); dwError = GetLastError(); SetPrivilege(SE_RESTORE_NAME, dwOldRestorePrivilege, NULL); } if(!bSuccess && dwError == ERROR_ACCESS_DENIED) { // failed with access denied; if caller is impersonating then try as process HANDLE hToken = NULL; if(OpenThreadToken(GetCurrentThread(), TOKEN_QUERY | TOKEN_IMPERSONATE, TRUE, &hToken)) { if(RevertToSelf()) { // 3. process without privilege bSuccess = DeleteFile(lpFileName); dwError = GetLastError(); if(!bSuccess && dwError == ERROR_ACCESS_DENIED) { // failed with access denied; try with privilege bHasRestorePrivilege = SetPrivilege(SE_RESTORE_NAME, SE_PRIVILEGE_ENABLED, &dwOldRestorePrivilege); if(bHasRestorePrivilege) { // 4. process with privilege bSuccess = DeleteFile(lpFileName); dwError = GetLastError(); SetPrivilege(SE_RESTORE_NAME, dwOldRestorePrivilege, NULL); } } SetThreadToken(NULL, hToken); } CloseHandle(hToken); hToken = NULL; } } } if(!bSuccess) { SetLastError(dwError); } return bSuccess; } So first it tries as the caller. If that fails with access denied, it temporarily enables privileges in the caller's token and tries again. If that fails with access denied and the caller is impersonating, it temporarily unimpersonates and tries again. If that fails with access denied, it temporarily enables privileges in the process token and tries again. I think this should handle pretty much any situation, but I was wondering if there was a better way to achieve this? There are a lot of operations that we would potentially want to use this method (i.e. pretty much any operation that accesses securable objects).

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  • What would I use to remove escaped html from large sets of data.

    - by Elizabeth Buckwalter
    Our database is filled with articles retrieved from RSS feeds. I was unsure of what data I would be getting, and how much filtering was already setup (WP-O-Matic Wordpress plugin using the SimplePie library). This plugin does some basic encoding before insertion using Wordpress's built in post insert function which also does some filtering. I've figured out most of the filters before insertion, but now I have whacko data that I need to remove. This is an example of whacko data that I have data in one field which the content I want in the front, but this part removed which is at the end: <img src="http://feeds.feedburner.com/~ff/SoundOnTheSound?i=xFxEpT2Add0:xFbIkwGc-fk:V_sGLiPBpWU" border="0"></img> <img src="http://feeds.feedburner.com/~ff/SoundOnTheSound?d=qj6IDK7rITs" border="0"></img> &lt;img src=&quot;http://feeds.feedburner.com/~ff/SoundOnTheSound?i=xFxEpT2Add0:xFbIkwGc-fk:D7DqB2pKExk&quot; Notice how some of the images are escape and some aren't. I believe this has to do with the last part being cut off so as to be unrecognizable as an html tag, which then caused it to be html endcoded. Another field has only this which is now filtered before insertion, but I have to get rid of the others: &lt;img src=&quot;http://farm3.static.flickr.com/2183/2289902369_1d95bcdb85.jpg&quot; alt=&quot;post_img&quot; width=&quot;80&quot; (all examples are on one line, but broken up for readability) Question: What is the best way to work with the above escaped html (or portion of an html tag)? I can do it in Perl, PHP, SQL, Ruby, and even Python. I believe Perl to be the best at text parsing, so that's why I used the Perl tag. And PHP times out on large database operations, so that's pretty much out unless I wanted to do batch processing and what not. PS One of the nice things about using Wordpress's insert post function, is that if you use php's strip_tags function to strip out all html, insert post function will insert <p> at the paragraph points. Let me know if there's anything more that I can answer. Some article that didn't quite answer my questions. (http://stackoverflow.com/questions/2016751/remove-text-from-within-a-database-text-field) (http://stackoverflow.com/questions/462831/regular-expression-to-escape-html-ampersands-while-respecting-cdata)

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  • mysql_connect() causes page to not display (WAMP)

    - by VOIDHand
    I currently have a website running MySQL and PHP in which this is all working. I've tried installing WAMPServer to be able to work on the site on my own computer, but I have been having issues trying to get the site to work correctly. HTML and PHP files work correctly (by going to http://localhost/index.php, etc.). But some of the pages display "This Webpage is not available" (in Chrome) or "Internet Explorer cannot display this webpage", which leads me to think there is an error is the server, as when the page doesn't exist, it typically dispays "Oops! This link appears to be broken" or IE's standard 404 page. Each page in my site has an include() call to set up an instance of a class to handle all database transactions. This class opens the connection to the database in its constructor. I have found commenting out the contents of the constructor will allow the page to load, although this understandably causes errors later in the page. This is the contents of the included file: class dbAccess { private $db; function __construct() { $this->db = mysql_connect("externalURL","user","password") or die ("Connection for database not found."); mysql_select_db("dbName", $this->db) or die ("Database not selected"); } ... } As a note for what's happening here. I'm attempting to use the database on my site, rather than the local machine. The actual values of externalURL, dbName, user, and password work when I plug them into my database software and the file fine of the site, so I don't think the issue is with those values themselves, but rather some setting with Apache or Wamp. The issue persists if I try a local database as well. This is an excerpt of my Apache error log for one attempt at logging into the site: [Wed Apr 14 15:32:54 2010] [notice] Parent: child process exited with status 255 -- Restarting. [Wed Apr 14 15:32:54 2010] [notice] Apache/2.2.11 (Win32) PHP/5.3.0 configured -- resuming normal operations [Wed Apr 14 15:32:54 2010] [notice] Server built: Dec 10 2008 00:10:06 [Wed Apr 14 15:32:54 2010] [notice] Parent: Created child process 1756 [Wed Apr 14 15:32:55 2010] [notice] Child 1756: Child process is running [Wed Apr 14 15:32:55 2010] [notice] Child 1756: Acquired the start mutex. [Wed Apr 14 15:32:55 2010] [notice] Child 1756: Starting 64 worker threads. [Wed Apr 14 15:32:55 2010] [notice] Child 1756: Starting thread to listen on port 80. For the first line, isLoggedIn (from the first line) is a method of the class above. Assuming that the connection works, this error should disappear. I've tried searching for solutions online, but haven't been able to find anything to help. If you need any further information to help solve this issue, feel free to ask for it. (One more note, I don't even have Skype on this computer, so I can't see it being an issue, as this conflict seems to be the default response for any Wamp issue.) [Edit: Removed entry from the error log as it was solved as an unrelated issue]

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  • casting, converting, and input from textbox controls

    - by Matt
    Working on some .aspx.cs code and decided I would forget how to turn a textbox value into a useable integer or decimal. Be warned I'm pretty new to .asp. Wish I could say the same for c sharp. So the value going into my textbox (strawberryp_textbox) is "1" which I presume I can access with the .text property. Which I then parse into a int. The Error reads Format Exception was unhandled by user code. My other question is can I do operations on a session variable? protected void submit_order_button_Click(object sender, EventArgs e) { int strawberryp; int strawberrys; decimal money1 = decimal.Parse(moneybox1.Text); decimal money2 = decimal.Parse(moneybox2.Text); decimal money3 = decimal.Parse(moneybox3.Text); decimal money4 = decimal.Parse(moneybox4.Text); decimal money5 = decimal.Parse(moneybox5.Text); strawberryp = int.Parse(strawberryp_Textbox.Text); //THE PROBLEM RIGHT HERE! strawberrys = int.Parse(strawberrys_Textbox.Text); // Needs fixed int strawberryc = int.Parse(strawberryc_Textbox.Text); //fix int berryp = int.Parse(berryp_Textbox.Text); //fix int raspberryp = int.Parse(raspberryp_Textbox.Text); /fix decimal subtotal = (money1 * strawberryp) + (money2 * strawberrys) + (money3 * strawberryc) + (money4 * berryp) + (money5 * raspberryp); //check to see if you can multiply decimal and int to get a deciaml!! Session["passmysubtotal"] = subtotal; //TextBox2.Text; (strawberryp_Textbox.Text);//TextBox4.Text; add_my_order_button.Enabled = true; add_my_order_button.Visible = true; submit_order_button.Enabled = false; submit_order_button.Visible = false; strawberryp_Textbox.ReadOnly = false; strawberrys_Textbox.ReadOnly = false; strawberryc_Textbox.ReadOnly = false; berryp_Textbox.ReadOnly = false; raspberryp_Textbox.ReadOnly = false; Response.Redirect("reciept.aspx"); } Thanks for the help

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  • cuda/thrust: Trying to sort_by_key 2.8GB of data in 6GB of gpu RAM throws bad_alloc

    - by Sven K
    I have just started using thrust and one of the biggest issues I have so far is that there seems to be no documentation as to how much memory operations require. So I am not sure why the code below is throwing bad_alloc when trying to sort (before the sorting I still have 50% of GPU memory available, and I have 70GB of RAM available on the CPU)--can anyone shed some light on this? #include <thrust/device_vector.h> #include <thrust/sort.h> #include <thrust/random.h> void initialize_data(thrust::device_vector<uint64_t>& data) { thrust::fill(data.begin(), data.end(), 10); } #define BUFFERS 3 int main(void) { size_t N = 120 * 1024 * 1024; char line[256]; try { std::cout << "device_vector" << std::endl; typedef thrust::device_vector<uint64_t> vec64_t; // Each buffer is 900MB vec64_t c[3] = {vec64_t(N), vec64_t(N), vec64_t(N)}; initialize_data(c[0]); initialize_data(c[1]); initialize_data(c[2]); std::cout << "initialize_data finished... Press enter"; std::cin.getline(line, 0); // nvidia-smi reports 48% memory usage at this point (2959MB of // 6143MB) std::cout << "sort_by_key col 0" << std::endl; // throws bad_alloc thrust::sort_by_key(c[0].begin(), c[0].end(), thrust::make_zip_iterator(thrust::make_tuple(c[1].begin(), c[2].begin()))); std::cout << "sort_by_key col 1" << std::endl; thrust::sort_by_key(c[1].begin(), c[1].end(), thrust::make_zip_iterator(thrust::make_tuple(c[0].begin(), c[2].begin()))); } catch(thrust::system_error &e) { std::cerr << "Error: " << e.what() << std::endl; exit(-1); } return 0; }

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  • WPF Application Slow Unresponsive when demonstrating using remote sharing software

    - by Kev
    After spending 14 hours on this I think its time to share my woes and see if anyone has experienced this issue before. Ill describe the issue and tests I have done to rule out certain things. Ok so I have a WPF application which loads in data from an SQL database. I am using DevExpress Components for datagrids, ribbons etc.. and FluentNhibernate to provide a session for database operations. I am also using log4net to log events to a textfile. Using the application on my laptop with SQL Express 2008 works fine.. the application starts up, retrieves 1000 records and I can tab through the controls on the ribbon. Now, I decided to demo the application to a third party and used remote login/sharing software online to share my desktop with the other person so as I could load the application on my laptop and they could view me using the application. Now, the application takes approx 45 seconds to load... 30 seconds with a blank database where as, when im not sharing out my screen using the online software the application loads in about 7-10 seconds. As well as that, even using the controls in the application during the demo were very sticky, slow and unresponsive. During the sharing session though however I was able to use other applications without any problems.. everything else worked fine. But I cannot understand how my application works ok under normal conditions , even browsing the net at the same time etc... BUT totally fails to perform correctly when I am sharing a session with another user... the CPU usage shot up to 100% too at times when the application was trying to start up... Please see below a list of 3rd party dlls I am using as references in my project. DevExpress dlls FluidKit PixelLab.WPF PixelLab.Common Galasoft WPF Kit FluentNHibernate NHibernate Nhibernate.ByteCode.Castle Skype4ComLib TXTEXTControl log4net LinqKit All of these DLLs are in the output folder with the application dlls created from the class assemblys in the project. So when installed via an installer on a machine the dlls will be in the same application folder as the application file itself. Many thanks

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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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  • Good working habits to observe in project development?

    - by Will Marcouiller
    As my development experience grows, I see fit to stick to best practices from here and there to build somehow my own working practices while observing the conventions, etc. I'm currently working on a project which my goals is to graduate the security access model from an environment's Active Directory to another environment's automatically. I don't know for any of you, but as far as I'm concerned, I meet some real difficulties sticking to only one way, then develop. I mean, I learn something new everyday while visiting SO, and recently wanted to get acquainted with generics. On the other hand, I better know the Façade pattern which proved to be very practical in transactional programming in process systems. This seems to be less practical for desktop application as there are plenty of variables to consider in a desktop application that you don't have to care in transactional programming, as you're playing only with information data. As for my current project, I have: Groups; Organizational Units; Users. Which are all considered an entry in the Active Directory. This points out to be a good candidate for generics, as also approached this way by Bart de Smett's Linq to AD on CodePlex. He has a DirectorySource<T>, and to manage let's say groups, then he instantiate a source with the proper type: var groups = new DirectorySource<Group>(); This seems to be very a good way of doing. Despite, I seem to go from one pattern to another and I don't seem to be able to strictly stick to one. While I'm aware that one must not stay with only one way of doing, since each pattern statisfies certain advantages, while also illustrating disadvantages under some usage conditions, I seem to want to develop with both patterns having a singleton Façade class with the underlying factories which represent the sub systems: GroupsFactory; UsersFactory; OrganizationalUnitsFactory. Each of the factories offers the possible operations for their respective entity (group, user, OU). To make a very long story short, I often have plenty of ideas while developping and this causes me some trouble, as I go from an idea to another feeling completely lost after a while. Yet I understand the advantages and disavantages, I have no trouble choosing from one pattern to another depending on the situation. Nevertheless, when it comes to programming itself, if I'm not part of a team, I feel sometimes like I can't do anything good. That is, because I can't stand not doing something "perfect" the first time. The role I play within the project is both: the project manager and the programmer. I am more comfortable in the project manager role, architectural role, analytical role than the developer's. Has any of you some good habbits to observe in project development? Thanks to you all! =)

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  • chaining array of tasks with continuation

    - by Andrei Cristof
    I have a Task structure that is a little bit complex(for me at least). The structure is: (where T = Task) T1, T2, T3... Tn. There's an array (a list of files), and the T's represent tasks created for each file. Each T has always two subtasks that it must complete or fail: Tn.1, Tn.2 - download and install. For each download (Tn.1) there are always two subtasks to try, download from two paths(Tn.1.1, Tn.1.2). Execution would be: First, download file: Tn1.1. If Tn.1.1 fails, then Tn.1.2 executes. If either from download tasks returns OK - execute Tn.2. If Tn.2 executed or failed - go to next Tn. I figured the first thing to do, was to write all this structure with jagged arrays: private void CreateTasks() { //main array Task<int>[][][] mainTask = new Task<int>[_queuedApps.Count][][]; for (int i = 0; i < mainTask.Length; i++) { Task<int>[][] arr = GenerateOperationTasks(); mainTask[i] = arr; } } private Task<int>[][] GenerateOperationTasks() { //two download tasks Task<int>[] downloadTasks = new Task<int>[2]; downloadTasks[0] = new Task<int>(() => { return 0; }); downloadTasks[1] = new Task<int>(() => { return 0; }); //one installation task Task<int>[] installTask = new Task<int>[1] { new Task<int>(() => { return 0; }) }; //operations Task is jagged - keeps tasks above Task<int>[][] operationTasks = new Task<int>[2][]; operationTasks[0] = downloadTasks; operationTasks[1] = installTask; return operationTasks; } So now I got my mainTask array of tasks, containing nicely ordered tasks just as described above. However after reading the docs on ContinuationTasks, I realise this does not help me since I must call e.g. Task.ContinueWith(Task2). I'm stumped about doing this on my mainTask array. I can't write mainTask[0].ContinueWith(mainTask[1]) because I dont know the size of the array. If I could somehow reference the next task in the array (but without knowing its index), but cant figure out how. Any ideas? Thank you very much for your help. Regards,

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  • How can I limit the cache used by copying so there is still memory available for other cache?

    - by Peter
    Basic situation: I am copying some NTFS disks in openSuSE. Each one is 2TB. When I do this, the system runs slow. My guesses: I believe it is likely due to caching. Linux decides to discard useful cache (eg. kde4 bloat, virtual machine disks, LibreOffice binaries, Thunderbird binaries, etc.) and instead fill all available memory (24 GB total) with stuff from the copying disks, which will be read only once, then written and never used again. So then any time I use these apps (or kde4), the disk needs to be read again, and reading the bloat off the disk again makes things freeze/hiccup. Due to the cache being gone and the fact that these bloated applications need lots of cache, this makes the system horribly slow. Since it is USB,the disk and disk controller are not the bottleneck, so using ionice does not make it faster. I believe it is the cache rather than just the motherboard going too slow, because if I stop everything copying, it still runs choppy for a while until it recaches everything. And if I restart the copying, it takes a minute before it is choppy again. But also, I can limit it to around 40 MB/s, and it runs faster again (not because it has the right things cached, but because the motherboard busses have lots of extra bandwidth for the system disks). I can fully accept a performance loss from my motherboard's IO capability being completely consumed (which is 100% used, meaning 0% wasted power which makes me happy), but I can't accept that this caching mechanism performs so terribly in this specific use case. # free total used free shared buffers cached Mem: 24731556 24531876 199680 0 8834056 12998916 -/+ buffers/cache: 2698904 22032652 Swap: 4194300 24764 4169536 I also tried the same thing on Ubuntu, which causes a total system hang instead. ;) And to clarify, I am not asking how to leave memory free for the "system", but for "cache". I know that cache memory is automatically given back to the system when needed, but my problem is that it is not reserved for caching of specific things. Question: Is there some way to tell these copy operations to limit memory usage so some important things remain cached, and therefore any slowdowns are a result of normal disk usage and not rereading the same commonly used files? For example, is there a setting of max memory per process/user/file system allowed to be used as cache/buffers?

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