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  • List<element> initialization fires "Process is terminated due to StackOverflowException"

    - by netmajor
    I have structs like below and when I do that initialization: ArrayList nodesMatrix = null; List<vertex> vertexMatrix = null; List<bool> odwiedzone = null; List<element> priorityQueue = null; vertexMatrix = new List<vertex>(nodesNr + 1); nodesMatrix = new ArrayList(nodesNr + 1); odwiedzone = new List<bool>(nodesNr + 1); priorityQueue = new List<element>(); arr.NodesMatrix = nodesMatrix; arr.VertexMatrix = vertexMatrix; arr.Odwiedzone = odwiedzone; arr.PriorityQueue = priorityQueue; //only here i have exception debuger fires Process is terminated due to StackOverflowException :/ Some idea why this collection fires this exception ? private struct arrays { ArrayList nodesMatrix; public ArrayList NodesMatrix { get { return nodesMatrix; } set { nodesMatrix = value; } } List<vertex> vertexMatrix; public List<vertex> VertexMatrix { get { return vertexMatrix; } set { vertexMatrix = value; } } List<bool> odwiedzone; public List<bool> Odwiedzone { get { return odwiedzone; } set { odwiedzone = value; } } public List<element> PriorityQueue { get { return PriorityQueue; } set { PriorityQueue = value; } } } public struct element : IComparable { public double priority { get { return priority; } set { priority = value; } } public int node { get { return node; } set { node = value; } } public element(double _prio, int _node) { priority = _prio; node = _node; } #region IComparable Members public int CompareTo(object obj) { element elem = (element)obj; return priority.CompareTo(elem.priority); } #endregion

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  • Using FluentNHibernate + SQLite with .Net4?

    - by stiank81
    I have a WPF application running with .Net3.5 using FluentNHibernate, and all works fine. When I upgraded to VS2010 I ran into some odd problems, but after changing to use x64 variant of SQLite it worked fine again. Now I want to change to use .Net4, but this has turned into a more painful experience then I expected.. When calling FluentConfiguration.BuildConfiguration I get an exception thrown: FluentConfigurationException unhandled An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more detail The inner exception gives us more information: Message = "Could not create the driver from NHibernate.Driver.SQLite20Driver, NHibernate, Version=2.1.2.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4." It has an InnerException again: Exception has been thrown by the target of an invocation. Which again has an InnerException: The IDbCommand and IDbConnection implementation in the assembly System.Data.SQLite could not be found. Ensure that the assembly System.Data.SQLite is located in the application directory or in the Global Assembly Cache. If the assembly is in the GAC, use element in the application configuration file to specify the full name of the assembly. Now - to me it sounds like it doesn't find System.Data.SQLite.dll, but I can't understand this. Everywhere this is referenced I have "Copy Local", and I have verified that it is in every build folder for projects using SQLite. I have also copied it manually to every Debug folder of the solution - without luck. Notes: This exact same code worked just fine before I upgraded to .Net4. I did see some x64 x86 mismatch problems earlier, but I have switched to use x86 as the target platform and for all referenced dlls. I have verified that all files in the Debug-folder are x86. I have tried the precompiled Fluent dlls, I have tried compiling myself, and I have compiled my own version of Fluent using .Net4. I see that there are also others that have seen this problem, but I haven't really seen any solution yet. After @devio's answer I tried adding a reference to the SQLite dll. This didn't change anything, but I hope I made it right though.. This is what I added to the root node of the app.config file: <runtime> <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> <qualifyAssembly partialName="System.Data.SQLite" fullName="System.Data.SQLite, Version=1.0.60.0, Culture=neutral, PublicKeyToken=db937bc2d44ff139" /> </assemblyBinding> </runtime> Anyone out there using Fluent with .Net4 and SQLite successfully? Help! I'm lost...

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  • How to Determine the Size of MSADO Command Parameters

    - by Adam
    I am new to MS ADO and trying to understand how to set the size on command parameters as created by the command.CreateParameter (Name, Type, Direction, Size, Value) The documentation says the following: Size Optional. A Long value that specifies the maximum length for the parameter value in characters or bytes. ... If you specify a variable-length data type in the Type argument, you must either pass a Size argument or set the Size property of the Parameter object before appending it to the Parameters collection; otherwise, an error occurs. 1.) What should one pass for fixed-size parameters? Is it a "don't care"? I was a bit confused by the example found here, in which they set size to 3 for an adInteger parameter with Value set to a variant of type VT_I2 pPrmByRoyalty->Type = adInteger; pPrmByRoyalty->Size = 3; pPrmByRoyalty->Direction = adParamInput; pPrmByRoyalty->Value = vtroyal; VT_I2 implies two bytes. A tagVARIANT struct is 16 bytes. How did they land on three? I see that the enum value for adInteger happens to be three, but I suspect that is just a coincidence. So it's a bit confusing what to pass for fixed-size parameters. The team I'm working with has always passed sizeof(int) for adInteger, and it seems to work. Is that correct? Now, for "variable-length" parameters: we are instructed by the documentation to pass "the maximum length .. in characters or bytes". 2.) For adVarChar, is it sufficient to pass the max width as defined in the database? 3.) What about the Wide types (e.g. adVarWChar)? Is it characters or bytes? 4.) How about adVariant, which could contain fixed- or variable-length data? 5.) Do arrays ever come into play here? (we don't pass them as parameters, just curious) Any references or personal insights are welcome.

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  • abstract data type list. . .

    - by aldrin
    A LIST is an ordered collection of items where items may be inserted anywhere in the list. Implement a LIST using an array as follows: struct list { int *items; // pointer to the array int size; // actual size of the array int count; // number of items in the array }; typedef struct list *List; // pointer to the structure Implement the following functions: a) List newList(int size); - will create a new List and return its pointer. Allocate space for the structure, allocate space for the array, then initialize size and count, return the pointer. b) void isEmpty(List list); c) void display(List list); d) int contains(List list, int item); e) void remove(List list, int i) ; f) void insertAfter(List list,int item, int i); g) void addEnd(List list,int item) - add item at the end of the list – simply store the data at position count, then increment count. If the array is full, allocate an array twice as big as the original. count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 addEnd(list,40) will result to count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 40 h) void addFront(List list,int item) - shift all elements to the right so that the item can be placed at position 0, then increment count. Bonus: if the array is full, allocate an array twice as big as the original. count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 addFront(list,40) will result to count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 i) void removeFront(List list) - shift all elements to the left and decrement count; count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 removeFront(list) will result to count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 j) void remove(List list,int item) - get the index of the item in the list and then shift all elements to the count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 remove(list,10) will result to count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 15 20 30

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  • How to bind a WPF CustomControl to a ListBox

    - by VivyG
    I've just started to learn WPF this week so please accept my apologies if I am being stupid or missing fundamental points! Iam trying to build a very simple Contact browser. I have a Collection of Contact objects that displayed in a ListBox control which shows the FullName of the Contact and to the right I have a customControl called BasicContactCard. This is the XAML for the ContacWindow that displays the ListBox: <DockPanel Width="auto" Height="auto" Margin="8 8 8 8"> <Border Height="56" HorizontalAlignment="Stretch" VerticalAlignment="Top" BorderThickness="1" CornerRadius="8" DockPanel.Dock="Top" Background="Beige"> <TextBox Height="32" Margin="23,5,135,5" Text="Search for contact here" FontStyle="Italic" Foreground="#FFAD9595" FontSize="14" BorderBrush="LightGray"/> </Border> <ListBox x:Name="contactList" DockPanel.Dock="Left" Width="192" Height="auto" Margin="5 4 0 8" /> <Grid> <Grid.RowDefinitions> <RowDefinition Height="1*" /> <RowDefinition Height="0.125*" /> </Grid.RowDefinitions> <local:BasicContactCard Margin="8 8 8 8" /> <Button Grid.Row="1" x:Name="exit" Content="Exit" HorizontalAlignment="Right" Width="50" Height="25" Click="exit_Click" /> </Grid> </DockPanel> and this is the XAML for the CustomControl: <DockPanel Width="auto " Height="auto" Margin="8,8,8,8"> <Grid Width="auto" Height="auto" DockPanel.Dock="Top"> <Grid.RowDefinitions> <RowDefinition Height="1*" /> <RowDefinition Height="1*" /> <RowDefinition Height="1*" /> <RowDefinition Height="1*" /> </Grid.RowDefinitions> <TextBlock x:Name="companyField" Grid.Row="0" Width="auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="8,8,8,8" Text="Company"/> <TextBlock x:Name="contactField" Grid.Row="1" Width="auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="8,8,8,8" Text="Contact"/> <TextBlock x:Name="phoneField" Grid.Row="2" Width="auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="8,8,8,8" Text="Phone"/> <TextBlock x:Name="emailField" Grid.Row="3" Width="auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="8,8,8,8" Text="email"/> </Grid> </DockPanel> The problem I have is how do I bind the individual elements of the CustomControl to the object behind the SelectedItem in the ListBox?

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  • Justifying UIVIews on the iPhone: Algorithm Help

    - by coneybeare
    I have been messing around with a way to justify align a collection of UIView subclasses within a containing view. I am having a little bit of trouble with the algorithm and was hoping someone could help spot my errors. Here is pseudocode of where I am now: // 1 see how many items there are int count = [items count]; // 2 figure out how much white space is left in the containing view float whitespace = [containingView width] - [items totalWidth]; // 3 Figure out the extra left margin to be applied to items[1] through items[count-1] float margin = whitespace/(count-1); // 4 Figure out the size of every subcontainer if it was evenly split float subcontainerWidth = [containingView width]/count; // 5 Apply the margin, starting at the second item for (int i = 1; i < [items count]; i++) { UIView *item = [items objectAtIndex:i]; [item setLeftMargin:(margin + i*subcontainerWidth)]; } The items do not appear to be evenly spaced here. Not even close. Where am I going wrong? Here is a shot of this algorithm in action: EDIT: The code above is pseudocode. I added the actual code here but it might not make sense if you are not familiar with the three20 project. @implementation TTTabStrip (JustifiedBarCategory) - (CGSize)layoutTabs { CGSize size = [super layoutTabs]; CGPoint contentOffset = _scrollView.contentOffset; _scrollView.frame = self.bounds; _scrollView.contentSize = CGSizeMake(size.width + kTabMargin, self.height); CGFloat contentWidth = size.width + kTabMargin; if (contentWidth < _scrollView.size.width) { // do the justify logic // see how many items there are int count = [_tabViews count]; // 2 figure out how much white space is left float whitespace = _scrollView.size.width - contentWidth; // 3 increase the margin on those items somehow to reflect. it should be (whitespace) / count-1 float margin = whitespace/(count-1); // 4 figure out starting point float itemWidth = (_scrollView.size.width-kTabMargin)/count; // apply the margin for (int i = 1; i < [_tabViews count]; i++) { TTTab *tab = [_tabViews objectAtIndex:i]; [tab setLeft:(margin + i*itemWidth)]; } } else { // do the normal, scrollbar logic _scrollView.contentOffset = contentOffset; } return size; } @end

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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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  • Bind listbox in WPF with grouping

    - by Michael Stoll
    Hi, I've got a collection of ViewModels and want to bind a ListBox to them. Doing some investigation I found this. So my ViewModel look like this (Pseudo Code) interface IItemViewModel { string DisplayName { get; } } class AViewModel : IItemViewModel { string DisplayName { return "foo"; } } class BViewModel : IItemViewModel { string DisplayName { return "foo"; } } class ParentViewModel { IEnumerable<IItemViewModel> Items { get { return new IItemViewModel[] { new AItemViewModel(), new BItemViewModel() } } } } class GroupViewModel { static readonly GroupViewModel GroupA = new GroupViewModel(0); static readonly GroupViewModel GroupB = new GroupViewModel(1); int GroupIndex; GroupViewModel(int groupIndex) { this.GroupIndex = groupIndex; } string DisplayName { get { return "This is group " + GroupIndex.ToString(); } } } class ItemGroupTypeConverter : IValueConverter { object Convert(object value, Type targetType, object parameter, CultureInfo culture) { if (value is AItemViewModel) return GroupViewModel.GroupA; else return GroupViewModel.GroupB; } } And this XAML <UserControl.Resources> <vm:ItemsGroupTypeConverter x:Key="ItemsGroupTypeConverter "/> <CollectionViewSource x:Key="GroupedItems" Source="{Binding Items}"> <CollectionViewSource.GroupDescriptions> <PropertyGroupDescription Converter="{StaticResource ItemsGroupTypeConverter }"/> </CollectionViewSource.GroupDescriptions> </CollectionViewSource> </UserControl.Resources> <ListBox ItemsSource="{Binding Source={StaticResource GroupedItems}}"> <ListBox.GroupStyle> <GroupStyle> <GroupStyle.HeaderTemplate> <DataTemplate> <TextBlock Text="{Binding DisplayName}" FontWeight="bold" /> </DataTemplate> </GroupStyle.HeaderTemplate> </GroupStyle> </ListBox.GroupStyle> <ListBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding DisplayName}" /> </DataTemplate> </ListBox.ItemTemplate> </ListBox> This works somehow, exept of the fact that the binding of the HeaderTemplate does not work. Anyhow I'd prefer omitting the TypeConverter and the CollectionViewSource. Isn't there a way to use a property of the ViewModel for Grouping? I know that in this sample scenario it would be easy to replace the GroupViewModel with a string an have it working, but that's not an option. So how can I bind the HeaderTemplate to the GroupViewModel?

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  • Socket server with multiple clients, sending messages to many clients without hurting liveliness

    - by Karl Johanson
    I have a small socket server, and I need to distribute various messages from client-to-client depending on different conditionals. However I think I have a small problem with livelyness in my current code, and is there anything wrong in my approach: public class CuClient extends Thread { Socket socket = null; ObjectOutputStream out; ObjectInputStream in; CuGroup group; public CuClient(Socket s, CuGroup g) { this.socket = s; this.group = g; out = new ObjectOutputStream(this.socket.getOutputStream()); out.flush(); in = new ObjectInputStream(this.socket.getInputStream()); } @Override public void run() { String cmd = ""; try { while (!cmd.equals("client shutdown")) { cmd = (String) in.readObject(); this.group.broadcastToGroup(this, cmd); } out.close(); in.close(); socket.close(); } catch (Exception e) { System.out.println(this.getName()); e.printStackTrace(); } } public void sendToClient(String msg) { try { this.out.writeObject(msg); this.out.flush(); } catch (IOException ex) { } } And my CuGroup: public class CuGroup { private Vector<CuClient> clients = new Vector<CuClient>(); public void addClient(CuClient c) { this.clients.add(c); } void broadcastToGroup(CuClient clientName, String cmd) { Iterator it = this.clients.iterator(); while (it.hasNext()) { CuClient cu = (CuClient)it.next(); cu.sendToClient(cmd); } } } And my main-class: public class SmallServer { public static final Vector<CuClient> clients = new Vector<CuClient>(10); public static boolean serverRunning = true; private ServerSocket serverSocket; private CuGroup group = new CuGroup(); public void body() { try { this.serverSocket = new ServerSocket(1337, 20); System.out.println("Waiting for clients\n"); do { Socket s = this.serverSocket.accept(); CuClient t = new CuClient(s,group); System.out.println("SERVER: " + s.getInetAddress() + " is connected!\n"); t.start(); } while (this.serverRunning); } catch (IOException ex) { ex.printStackTrace(); } } public static void main(String[] args) { System.out.println("Server"); SmallServer server = new SmallServer(); server.body(); } } Consider the example with many more groups, maybe a Collection of groups. If they all synchronize on a single Object, I don't think my server will be very fast. I there a pattern or something that can help my liveliness?

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  • How to use DataContractSerializer to create xml with tag names that match my known types

    - by mezoid
    I have the following data contract: [CollectionDataContract(Name="MyStuff")] public class MyStuff : Collection<object> {} [DataContract(Name = "Type1")] [KnownType(typeof(Type1))] public class Type1 { [DataMember(Name = "memberId")] public int Id { get; set; } } [DataContract(Name = "Type2")] [KnownType(typeof(Type2))] public class Type2 { [DataMember(Name = "memberId")] public int Id { get; set; } } Which I serialize to xml as follows: MyStuff pm = new MyStuff(); Type1 t1 = new Type1 { Id = 111 }; Type2 t2 = new Type2 { Id = 222 }; pm.Add(t1); pm.Add(t2); string xml; StringBuilder serialXML = new StringBuilder(); DataContractSerializer dcSerializer = new DataContractSerializer(typeof(MyStuff)); using (XmlWriter xWriter = XmlWriter.Create(serialXML)) { dcSerializer.WriteObject(xWriter, pm); xWriter.Flush(); xml = serialXML.ToString(); } The resultant xml string looks like this: <?xml version="1.0" encoding="utf-16"?> <MyStuff xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/"> <anyType i:type="Type1"> <memberId>111</memberId> </anyType> <anyType i:type="Type2"> <memberId>222</memberId> </anyType> </MyStuff> Does anyone know how I can get it to instead use the name of my known types rather than anyType in the xml tag? I'm wanting it to look like this: <?xml version="1.0" encoding="utf-16"?> <MyStuff xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/"> <Type1> <memberId>111</memberId> </Type1> <Type2> <memberId>222</memberId> </Type2> </MyStuff>

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  • Scared of Calculus - Required to pass Differential Calculus as part of my Computer science major

    - by ke3pup
    Hi guys I'm finishing my Computer science degree in university but my fear of maths (lack of background knowledge) made me to leave all my maths units til' the very end which is now. i either take them on and pass or have to give up. I've passed all my programming units easily but knowing my poor maths skills won't do i've been staying clear of the maths units. I have to pass Differential Calculus and Linear Algebra first. With a help of book named "Linear Algebra: A Modern Introduction" i'm finding myself on track and i think i can pass the Linear Algebra unit. But with differential calculus i can't find a book to help me. They're either too advanced or just too simple for what i have to learn. The things i'm required to know for this units are: Set notation, the real number line, Complex numbers in cartesian form. Complex plane, modulus. Complex numbers in polar form. De Moivre’s Theorem. Complex powers and nth roots. Definition of ei? and ez for z complex. Applications to trigonometry. Revision of domain and range of a function Working in R3. Curves and surfaces. Functions of 2 variables. Level curves.Partial derivatives and tangent planes. The derivative as a difference quotient. Geometric significance of the derivative. Discussion of limit. Higher order partial derivatives. Limits of f(x,y). Continuity. Maxima and minima of f(x,y). The chain rule. Implicit differentiation. Directional derivatives and the gradient. Limit laws, l’Hoˆpital’s rule, composition law. Definition of sinh and cosh and their inverses. Taylor polynomials. The remainder term. Taylor series. Is there a book to help me get on track with the above? Being a student i can't buy too many books hence why i'm looking for a book that covers topics I need to know. The University library has a fairly limited collection which i took as loan but didn't find useful as it was too complex.

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  • Rush Hour - Solving the game

    - by Rubys
    Rush Hour if you're not familiar with it, the game consists of a collection of cars of varying sizes, set either horizontally or vertically, on a NxM grid that has a single exit. Each car can move forward/backward in the directions it's set in, as long as another car is not blocking it. You can never change the direction of a car. There is one special car, usually it's the red one. It's set in the same row that the exit is in, and the objective of the game is to find a series of moves (a move - moving a car N steps back or forward) that will allow the red car to drive out of the maze. I've been trying to think how to solve this problem computationally, and I can really not think of any good solution. I came up with a few: Backtracking. This is pretty simple - Recursion and some more recursion until you find the answer. However, each car can be moved a few different ways, and in each game state a few cars can be moved, and the resulting game tree will be HUGE. Some sort of constraint algorithm that will take into account what needs to be moved, and work recursively somehow. This is a very rough idea, but it is an idea. Graphs? Model the game states as a graph and apply some sort of variation on a coloring algorithm, to resolve dependencies? Again, this is a very rough idea. A friend suggested genetic algorithms. This is sort of possible but not easily. I can't think of a good way to make an evaluation function, and without that we've got nothing. So the question is - How to create a program that takes a grid and the vehicle layout, and outputs a series of steps needed to get the red car out? Sub-issues: Finding some solution. Finding an optimal solution (minimal number of moves) Evaluating how good a current state is Example: How can you move the cars in this setting, so that the red car can "exit" the maze through the exit on the right?

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  • "EXC_BAD_ACCESS: Unable to restore previously selected frame" Error, Array size?

    - by Job
    Hi there, I have an algorithm for creating the sieve of Eratosthenes and pulling primes from it. It lets you enter a max value for the sieve and the algorithm gives you the primes below that value and stores these in a c-style array. Problem: Everything works fine with values up to 500.000, however when I enter a large value -while running- it gives me the following error message in xcode: Program received signal: “EXC_BAD_ACCESS”. warning: Unable to restore previously selected frame. Data Formatters temporarily unavailable, will re-try after a 'continue'. (Not safe to call dlopen at this time.) My first idea was that I didn't use large enough variables, but as I am using 'unsigned long long int', this should not be the problem. Also the debugger points me to a point in my code where a point in the array get assigned a value. Therefore I wonder is there a maximum limit to an array? If yes: should I use NSArray instead? If no, then what is causing this error based on this information? EDIT: This is what the code looks like (it's not complete, for it fails at the last line posted). I'm using garbage collection. /*--------------------------SET UP--------------------------*/ unsigned long long int upperLimit = 550000; // unsigned long long int sieve[upperLimit]; unsigned long long int primes[upperLimit]; unsigned long long int indexCEX; unsigned long long int primesCounter = 0; // Fill sieve with 2 to upperLimit for(unsigned long long int indexA = 0; indexA < upperLimit-1; ++indexA) { sieve[indexA] = indexA+2; } unsigned long long int prime = 2; /*-------------------------CHECK & FIND----------------------------*/ while(!((prime*prime) > upperLimit)) { //check off all multiples of prime for(unsigned long long int indexB = prime-2; indexB < upperLimit-1; ++indexB) { // Multiple of prime = 0 if(sieve[indexB] != 0) { if(sieve[indexB] % prime == 0) { sieve[indexB] = 0; } } } /*---------------- Search for next prime ---------------*/ // index of current prime + 1 unsigned long long int indexC = prime - 1; while(sieve[indexC] == 0) { ++indexC; } prime = sieve[indexC]; // Store prime in primes[] primes[primesCounter] = prime; // This is where the code fails if upperLimit > 500000 ++primesCounter; indexCEX = indexC + 1; } As you may or may not see, is that I am -very much- a beginner. Any other suggestions are welcome of course :)

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  • Silverlight 4 DataBinding: Binding to ObservableCollection<string> not working anymore

    - by Kurt
    Upgrading from SL3 - SL4. First problem: this throws a parser exception: <StackPanel Name={Binding} /> (same with x:Name) Collection is ObservableCollection<string>. Worked fine in SL3. So it seems that SL4 doen't allow binding to the Name property. Huh? So: changed to <StackPanel Tag={Binding} /> ... since I just need to ID the control in code behind. So here's the bug ('cuz this has got to be a bug!): In this frag, AllAvailableItems is an ObservableCollection<string>: <ItemsControl Name="lbItems" ItemsSource="{Binding AllAvailableItems}" Height="Auto" Width="Auto" BorderBrush="Transparent" BorderThickness="0" VerticalAlignment="Top" HorizontalAlignment="Left" Margin="12,6,0,0"> <ItemsControl.ItemTemplate> <DataTemplate> <Grid> <Grid.RowDefinitions> <RowDefinition /> <RowDefinition /> </Grid.RowDefinitions> <CheckBox Tag="{Binding}" Checked="ItemChecked_Click" Unchecked="ItemUnchecked_Click" Style="{StaticResource CheckBoxStyle}" Grid.Row="0"> <CheckBox.Content> <TextBlock Text="{Binding}" Style="{StaticResource FormLJustStyle}" /> </CheckBox.Content> </CheckBox> <StackPanel Tag="{Binding}" Orientation="Vertical" Grid.Row="1"> <configControls:ucLanguage /> <!-- simple user control --> </StackPanel> </Grid> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> In the code behind, I use a recursive function to find the Dependency object with either the Name or Tag property provided: public static T FindVisualChildByName<T>(DependencyObject parent, string name, DependencyProperty propToUse) where T : DependencyObject { for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++) { var child = VisualTreeHelper.GetChild(parent, i); string controlName = child.GetValue(propToUse) as string; if (controlName == name) { return child as T; } else { T result = FindVisualChildByName<T>(child, name, propToUse); if (result != null) return result; } } return null; } OK, get this: in the code behind, I can get the control that is ORDERED FIRST in the XAML! In other words, if I put the CheckBox first, I can retrieve the CheckBox, but no StackPanel. And vice-versa. This all worked fine in SL3. Any help, ideas ... ? Thanks - Kurt

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  • MVC 2 AntiForgeryToken - Why symmetric encryption + IPrinciple?

    - by Brad R
    We recently updated our solution to MVC 2, and this has updated the way that the AntiForgeryToken works. Unfortunately this does not fit with our AJAX framework any more. The problem is that MVC 2 now uses symmetric encryption to encode some properties about the user, including the user's Name property (from IPrincipal). We are able to securely register a new user using AJAX, after which subsequent AJAX calls will be invalid as the anti forgery token will change when the user has been granted a new principal. There are also other cases when this may happen, such as a user updating their name etc. My main question is why does MVC 2 even bother using symmetric encryption? Any then why does it care about the user name property on the principal? If my understanding is correct then any random shared secret will do. The basic principle is that the user will be sent a cookie with some specific data (HttpOnly!). This cookie is then required to match a form variable sent back with each request that may have side effects (POST's usually). Since this is only meant to protect from cross site attacks it is easy to craft up a response that would easily pass the test, but only if you had full access to the cookie. Since a cross site attacker is not going to have access to your user cookies you are protected. By using symmetric encryption, what is the advantage in checking the contents of the cookie? That is, if I already have sent an HttpOnly cookie the attacker cannot override it (unless a browser has a major security issue), so why do I then need to check it again? After having a think about it it appears to be one of those 'added layer of security' cases - but if your first line of defence has fallen (HttpOnly) then the attacker is going to get past the second layer anyway as they have full access to the users cookie collection, and could just impersonate them directly, instead of using an indirect XSS/CSRF attack. Of course I could be missing a major issue, but I haven't found it yet. If there are some obvious or subtle issues at play here then I would like to be aware of them.

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  • How to make Flash 'play well with others'?

    - by Sensei James
    What up fam. So this isn't a question asking about memory management schemes; for those of you who may not know, the Flash Virtual Machine relies on garbage collection by using reference counting and mark and sweep (for good coverage of these topics, check out Grant Skinner's article and presentation). And yes, Flash also provides the "delete" operator, which can (unfortunately only) be used to remove the properties of dynamic objects. What I want to know is how to make it so that Flash programs don't continue to consume CPU and memory while running in the background (save loading content or communicating remotely, for example). The motivation for this question comes in part from Apple's ban on cross compiled applications (in its SDK 4) on the grounds that they do not behave as predicted with the multitasking feature central to iPhone OS 4. My intention is not only to make Flash programs that will 'pass muster' as far as multitasking in iPhone OS 4, but also to simply make better (behaving) Flash programs. Put another way, how might a Flash application mimic the multitasking feature of iPhone OS 4? Does the Flash API provide the means for a developer to put their applications to 'sleep' while other programs run, and then to 'awaken' them just as quickly? In our own program, we might do something as crude as detecting when the user has been idle (no mouse motion or key press) for (say) four seconds: var idle_id:uint = setInterval(4000, pause_program); var current_movie_clip:MovieClip; var current_frame:uint; ... // on Mouse move or key press... clearInterval(idle_id); idle_id = setInterval(4000, pause_program); ... function pause_program():void { current_movie_clip = event.target as MovieClip; current_frame = current_movie_clip.currentFrame; MovieClip(root).gotoAndStop("program_pause_screen"); } (on the program pause screen) resume_button.addEventListener(MouseEvent.CLICK, resume_program); function resume_program(event:MouseEvent) { current_movie_clip.gotoAndPlay(current_frame); } If that's the right idea, what's the best way to detect that an application should be shelved? And, more importantly, is it possible for Flash Player to detect that some of its running programs are idle, and to similarly shelve them until the user performs an action to resume them? (Please feel free to answer as much or as little of the many questions I've posed.)

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  • Using NHibernate to map a nChar column to an enumerated type

    - by Morrislgn
    Hello Folks, I am trying to map a table frp, a SQL Server 2005 DB to a class which contains an enum: public class MyClass{ private YesNoOptional addressSetting; public YesNoOptional AddressSetting{ {get; set;} } } public enum YesNoOptional { Yes, No, Optional } This will dictate that one of three values is inserted into the corresponding column - 'Y', 'N', 'O'. This column is of type nchar(1). My mapping file is like so (addressSetting is the property which is causing the problem): <class name="IncidentDefinition" table="IR_INCIDENT_DEF" lazy="false" > <id name="Guid" column="INT_GUID" > <generator class="guid"></generator> </id> <property name="Reference" column="INT_REF" ></property> <property name="Description" column="INT_DESCRIPTION" ></property> <property name="AddressSetting" column="INT_ADDRESS_REQ" ></property> <property name="Active" column="INT_ACTIVE" type="YesNo"></property> <property name="PinDocId" column="INT_PIN_DOC_ID"></property> </class> Using the config above I get the following error: NHibernate.ADOException: could not initialize a collection: System.FormatException: Input string was not in a correct format.. If I try to map the enum using a custom type like so: <property name="AddressSetting" column="INT_ADDRESS_REQ" type="ML.Types.YesNoOptional, ML.Types" ></property> Error: System.FormatException: Input string was not in a correct format. Next, if I try using a specific type like so: <property name="AddressSetting" column="INT_ADDRESS_REQ" type="String" ></property> This error is generated: NHibernate.PropertyAccessException: The type System.String can not be assigned to a property of type System.ArgumentException: Object of type 'System.String' cannot be converted to type 'ML.Types.YesNoOptional'.. As a last resort I tried to specify the type as a char like so: <property name="AddressSetting" column="INT_ADDRESS_REQ" type="Char" ></property> This works a bit better, as it in it doesnt throw an error, however instead of returning the character from the table and mapping it to the enumerated type the ASCII value of the character is returned instead - so Y is represented by 89! I am hoping someone can explain what I am doing wrong and\or how why this is happening please? Thanks Morris

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  • Using ViewModel Pattern with MVC 2 Strongly Typed HTML Helpers

    - by Brettski
    I am working with ASP.NET MVC2 RC and can't figure out how to get the HTML helper, TextBoxfor to work with a ViewModel pattern. When used on an edit page the data is not saved when UpdateModel() is called in the controller. I have taken the following code examples from the NerdDinner application. Edit.aspx <%@ Language="C#" Inherits="System.Web.Mvc.ViewUserControl<NerdDinner.Models.DinnerFormViewModel>" %> ... <p> // This works when saving in controller (MVC 1) <label for="Title">Dinner Title:</label> <%= Html.TextBox("Title", Model.Dinner.Title) %> <%= Html.ValidationMessage("Title", "*") %> </p> <p> // This does not work when saving in the controller (MVC 2) <label for="Title">Dinner Title:</label> <%= Html.TextBoxFor(model => model.Dinner.Title) %> <%= Html.ValidationMessageFor(model=> model.Dinner.Title) %> </p> DinnerController // POST: /Dinners/Edit/5 [HttpPost, Authorize] public ActionResult Edit(int id, FormCollection collection) { Dinner dinner = dinnerRepository.GetDinner(id); if (!dinner.IsHostedBy(User.Identity.Name)) return View("InvalidOwner"); try { UpdateModel(dinner); dinnerRepository.Save(); return RedirectToAction("Details", new { id=dinner.DinnerID }); } catch { ModelState.AddModelErrors(dinner.GetRuleViolations()); return View(new DinnerFormViewModel(dinner)); } } When the original helper style is used (Http.TextBox) the UpdateModel(dinner) call works as expected and the new values are saved. When the new (MVC2) helper style is used (Http.TextBoxFor) the UpdateModel(dinner) call does not update the values. Yes, the current values are loaded into the edit page on load. Is there something else which I need to add to the controller code for it to work? The new helper works fine if I am just using a model and not a ViewModel pattern. Thank you.

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  • SQLiteException and SQLite error near "(": syntax error with Subsonic ActiveRecord

    - by nvuono
    I ran into an interesting error with the following LiNQ query using LiNQPad and when using Subsonic 3.0.x w/ActiveRecord within my project and wanted to share the error and resolution for anyone else who runs into it. The linq statement below is meant to group entries in the tblSystemsValues collection into their appropriate system and then extract the system with the highest ID. from ksf in KeySafetyFunction where ksf.Unit == 2 && ksf.Condition_ID == 1 join sys in tblSystems on ksf.ID equals sys.KeySafetyFunction join xval in (from t in tblSystemsValues group t by t.tblSystems_ID into groupedT select new { sysId = groupedT.Key, MaxID = groupedT.Max(g=>g.ID), MaxText = groupedT.First(gt2 => gt2.ID == groupedT.Max(g=>g.ID)).TextValue, MaxChecked = groupedT.First(gt2 => gt2.ID == groupedT.Max(g=>g.ID)).Checked }) on sys.ID equals xval.sysId select new {KSFDesc=ksf.Description, sys.Description, xval.MaxText, xval.MaxChecked} On its own, the subquery for grouping into groupedT works perfectly and the query to match up KeySafetyFunctions with their System in tblSystems also works perfectly on its own. However, when trying to run the completed query in linqpad or within my project I kept running into a SQLiteException SQLite Error Near "(" First I tried splitting the queries up within my project because I knew that I could just run a foreach loop over the results if necessary. However, I continued to receive the same exception! I eventually separated the query into three separate parts before I realized that it was the lazy execution of the queries that was killing me. It then became clear that adding the .ToList() specifier after the myProtectedSystem query below was the key to avoiding the lazy execution after combining and optimizing the query and being able to get my results despite the problems I encountered with the SQLite driver. // determine the max Text/Checked values for each system in tblSystemsValue var myProtectedValue = from t in tblSystemsValue.All() group t by t.tblSystems_ID into groupedT select new { sysId = groupedT.Key, MaxID = groupedT.Max(g => g.ID), MaxText = groupedT.First(gt2 => gt2.ID ==groupedT.Max(g => g.ID)).TextValue, MaxChecked = groupedT.First(gt2 => gt2.ID ==groupedT.Max(g => g.ID)).Checked}; // get the system description information and filter by Unit/Condition ID var myProtectedSystem = (from ksf in KeySafetyFunction.All() where ksf.Unit == 2 && ksf.Condition_ID == 1 join sys in tblSystem.All() on ksf.ID equals sys.KeySafetyFunction select new {KSFDesc = ksf.Description, sys.Description, sys.ID}).ToList(); // finally join everything together AFTER forcing execution with .ToList() var joined = from protectedSys in myProtectedSystem join protectedVal in myProtectedValue on protectedSys.ID equals protectedVal.sysId select new {protectedSys.KSFDesc, protectedSys.Description, protectedVal.MaxChecked, protectedVal.MaxText}; // print the gratifying debug results foreach(var protectedItem in joined) { System.Diagnostics.Debug.WriteLine(protectedItem.Description + ", " + protectedItem.KSFDesc + ", " + protectedItem.MaxText + ", " + protectedItem.MaxChecked); }

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  • NHibernate - I have many, but I only want one!

    - by MartinF
    Hello, I have a User which can have many Emails. This is mapped through a List collection (exposed by IEnumerable Emails on the User). For each User one of the Emails will be the Primary one ("Boolean IsPrimary" property on Email). How can I get the primary Email from User without NHibernate loads every email for the User ? I have the following two entities, with a corresponding table for each public class User { public virtual int Id { get; set; } public virtual IEnumerable<Email> Emails { get; set; } // public virtual Email PrimaryEmail { get; set; } - Possible somehow ? } public class Email { public virtual int Id { get; set; } public virtual String Address { get; set; } public virtual Boolean IsPrimary { get; set; } public virtual User User { get; set; } } Can I map a "Email PrimaryEmail" property etc. on the User to the Email which have "IsPrimary=1" set somehow ? Maybe using a Sql Formula ? a View ? a One-To-One relationship ? or another way ? It should be possible to change the primary email to be one of the other emails, so i would like to keep them all in 1 table and just change the IsPrimary property. Using a Sql Formula, is it be possible to keep the "PrimaryEmail" property on the User up-to-date, if I set the IsPrimary property on the current primary email to false, and then afterwards set the PrimaryEmail property to the email which should be the new primary email and set IsPrimary to true ? Will NHibernate track changes on the "old/current" primary Email loaded by the Sql Formula ? What about the 1 level cache and the 2 level cache when using SqlFormula ? I dont know if it could work by using a View ? Then i guess the Email could be mapped like a Component ? Will it work when updating the Email data when loaded from the View ? Is there a better way ? As I have a bi-directional relationship between User and Email I could in many cases of course query the primary Email and then use the "User" property on the Email to get the User (instead of the other way around - going from User to the primary Email) Hope someone can help ?

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  • WPF Linear Fill

    - by Ben
    Hi, I have found some example code that creates a gradient fill in a WPF rectangle control: <Rectangle Height="{Binding ElementName=txtName}" Width="{Binding ElementName=txtName}"> <Rectangle.Fill> <LinearGradientBrush> <GradientStop Color="Silver" Offset="0.0" /> <GradientStop Color="Black" Offset="0.5" /> <GradientStop Color="white" Offset="1.0" /> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> I have some written some code that displays a collection of ListBox's that contain details from MyObject: <UserControl.Resources> <DataTemplate x:Key="CustomerTemplate"> <Border BorderThickness="2" BorderBrush="Silver" CornerRadius="5" Padding="1" Height="50"> <Grid x:Name="thisGrid"> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" /> <ColumnDefinition Width="Auto" /> </Grid.ColumnDefinitions> <StackPanel Orientation="Horizontal" > <Image Source="C:\MyImage.jpg" Height="50" Width="100" ></Image> </StackPanel> <Border Grid.Column="1" Margin="0" Padding="0"> <StackPanel Orientation="Vertical"> <TextBlock Name="txtName" Text="{Binding Name}" Background="Silver" Foreground="Black" FontSize="16" FontWeight="Bold" Height="25"/> </StackPanel> </Border> </Grid> </Border> </DataTemplate> </UserControl.Resources> <ListBox ItemsSource="{Binding}" ItemTemplate="{StaticResource CustomerTemplate}" Name="grdList" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" > </ListBox> I would like to apply the same stlye of fill that i get with the first example, in each of my ListBox's. I can't quite figure out how to do this. Can anyone help? Thanks

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  • Problems using FluentNHibernate + SQLite with .NET4?

    - by stiank81
    I have a WPF application running with VS2010 .Net3.5 using Nhibernate with FluentNHibernate + SQLite, and all works fine. Now I want to change to use .Net4, but this has turned into a more painful experience then I expected.. When setting up the connection a FluentConfigurationException is thrown from FluentConfiguration.BuildConfiguration saying: An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more details. The inner exception gives us more information: Could not create the driver from NHibernate.Driver.SQLite20Driver, NHibernate, Version=2.1.2.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4. It has an InnerException again: Exception has been thrown by the target of an invocation. Which again has an InnerException: The IDbCommand and IDbConnection implementation in the assembly System.Data.SQLite could not be found. Ensure that the assembly System.Data.SQLite is located in the application directory or in the Global Assembly Cache. If the assembly is in the GAC, use element in the application configuration file to specify the full name of the assembly. Now - to me it sounds like it doesn't find System.Data.SQLite.dll, but I can't understand this. Everywhere this is referenced I have "Copy Local", and I have verified that it is in every build folder for projects using SQLite. I have also copied it manually to every Debug folder of the solution - without luck. Notes: This is exactly the same code that worked just fine before I upgraded to .Net4. I did see some x64 x86 mismatch problems earlier, but I have switched to use x86 as the target platform and for all referenced dlls. I have verified that all files in the Debug-folder are x86. I have tried the precompiled Fluent dlls, I have tried compiling myself, and I have compiled my own version of Fluent using .Net4. I see that there are also others that have seen this problem, but I haven't really seen any solution yet. After @devio's answer I tried adding a reference to the SQLite dll. This didn't change anything, but I hope I made it right though.. This is what I added to the root node of the app.config file: <runtime> <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> <qualifyAssembly partialName="System.Data.SQLite" fullName="System.Data.SQLite, Version=1.0.60.0, Culture=neutral, PublicKeyToken=db937bc2d44ff139" /> </assemblyBinding> </runtime> Anyone out there using Fluent with .Net4 and SQLite successfully? Help! I'm lost...

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  • Why don't my scrollbars work properly when programmatically hiding rows in silverlight Datagrid?

    - by Luke Vilnis
    I have a Silverlight datagrid with custom code that allows for +/- buttons on the lefthand side and can display a table with a tree structure. The +/- buttons are bound to a IsExpanded property on my ViewModelRows, as I call them. The visibility of rows is bound to an IsVisible property on the ViewModelRows which is determined based on whether or not all of the parent rows are expanded. Straightforward enough. This code works fine in that if I scroll up and down the grid with PageUp/PageDown or the arrow keys, all the right rows are hidden and everything has the right structure and I can play with the +/- buttons to my hearts content. However, the vertical scroll bar on the right hand side, although it starts off the correct size and it scrolls through the rows smoothly, when I collapse rows and then re-expand them, doesn't go back to its correct size. The scrollbar can still usually be moved around to scroll through the whole collection, but because it is too big, once the bar moves to the bottom, there are still more rows to go through and it sort of jerkily shoots all the way down to the bottom or sometimes fails to scroll at all. This is pretty hard to describe so I included a screenshot with the black lines drawn on to show the difference in scrollbar length even though the two grids have the same number of rows expanded. I think this might be a bug related to the way the Datagrid does virtualization of rows. It seems to me like it isn't properly keeping track of how tall each row is supposed to be when expansion states change. Is there a way to programmatically "poke" (read hack) it to recalculate its scrollbar size on LoadingRow or something ugly like that? I'd include a code sample but there's 2 c# files and 1 xaml file so I wanted to see if anyone else has heard of this sort of issue before I try to make it reproducible in a self-contained way. Once again, scrolling with the arrow keys works fine so I'm pretty sure the underlying logic and binding is working, there's just some issue with the row height not being calculated properly. Since I'm a new user, it won't let me use image tags so here's the link to a picture of the problem: http://img210.imageshack.us/img210/8760/messedupscrollbars.png

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  • Finding what makes strings unique in a list, can you improve on brute force?

    - by Ed Guiness
    Suppose I have a list of strings where each string is exactly 4 characters long and unique within the list. For each of these strings I want to identify the position of the characters within the string that make the string unique. So for a list of three strings abcd abcc bbcb For the first string I want to identify the character in 4th position d since d does not appear in the 4th position in any other string. For the second string I want to identify the character in 4th position c. For the third string it I want to identify the character in 1st position b AND the character in 4th position, also b. This could be concisely represented as abcd -> ...d abcc -> ...c bbcb -> b..b If you consider the same problem but with a list of binary numbers 0101 0011 1111 Then the result I want would be 0101 -> ..0. 0011 -> .0.. 1111 -> 1... Staying with the binary theme I can use XOR to identify which bits are unique within two binary numbers since 0101 ^ 0011 = 0110 which I can interpret as meaning that in this case the 2nd and 3rd bits (reading left to right) are unique between these two binary numbers. This technique might be a red herring unless somehow it can be extended to the larger list. A brute-force approach would be to look at each string in turn, and for each string to iterate through vertical slices of the remainder of the strings in the list. So for the list abcd abcc bbcb I would start with abcd and iterate through vertical slices of abcc bbcb where these vertical slices would be a | b | c | c b | b | c | b or in list form, "ab", "bb", "cc", "cb". This would result in four comparisons a : ab -> . (a is not unique) b : bb -> . (b is not unique) c : cc -> . (c is not unique) d : cb -> d (d is unique) or concisely abcd -> ...d Maybe it's wishful thinking, but I have a feeling that there should be an elegant and general solution that would apply to an arbitrarily large list of strings (or binary numbers). But if there is I haven't yet been able to see it. I hope to use this algorithm to to derive minimal signatures from a collection of unique images (bitmaps) in order to efficiently identify those images at a future time. If future efficiency wasn't a concern I would use a simple hash of each image. Can you improve on brute force?

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  • How to designing a generic databse whos layout may change over time?

    - by mawg
    Here's a tricky one - how do I programatically create and interrogate a database who's contents I can't really foresee? I am implementing a generic input form system. The user can create PHP forms with a WYSIWYG layout and use them for any purpose he wishes. He can also query the input. So, we have three stages: a form is designed and generated. This is a one-off procedure, although the form can be edited later. This designs the database. someone or several people make use of the form - say for daily sales reports, stock keeping, payroll, etc. Their input to the forms is written to the database. others, maybe management, can query the database and generate reports. Since these forms are generic, I can't predict the database structure - other than to say that it will reflect HTML form fields and consist of a the data input from collection of edit boxes, memos, radio buttons and the like. Questions and remarks: A) how can I best structure the database, in terms of tables and columns? What about primary keys? My first thought was to use the control name to identify each column, then I realized that the user can edit the form and rename, so that maybe "name" becomes "employee" or "wages" becomes ":salary". I am leaning towards a unique number for each. B) how best to key the rows? I was thinking of a timestamp to allow me to query and a column for the row Id from A) C) I have to handle column rename/insert/delete. Foe deletion, I am unsure whether to delete the data from the database. Even if the user is not inputting it from the form any more he may wish to query what was previously entered. Or there may be some legal requirements to retain the data. Any gotchas in column rename/insert/delete? D) For the querying, I can have my PHP interrogate the database to get column names and generate a form with a list where each entry has a database column name, a checkbox to say if it should be used in the query and, based on column type, some selection criteria. That ought to be enough to build searches like "position = 'senior salesman' and salary 50k". E) I probably have to generate some fancy charts - graphs, histograms, pie charts, etc for query results of numerical data over time. I need to find some good FOSS PHP for this. F) What else have I forgotten? This all seems very tricky to me, but I am database n00b - maybe it is simple to you gurus?

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