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  • operator overloading of stream extraction operator in C++ help

    - by Crystal
    I'm having some trouble overloading my stream extraction operator in C++ for a hw assignment. I'm not really sure why I am getting these compile errors since I thought I was doing it right... Here is my code: Complex.h #ifndef COMPLEX_H #define COMPLEX_H class Complex { //friend ostream &operator<<(ostream &output, const Complex &complexObj) const; public: Complex(double = 0.0, double = 0.0); // constructor Complex operator+(const Complex &) const; // addition Complex operator-(const Complex &) const; // subtraction void print() const; // output private: double real; // real part double imaginary; // imaginary part }; #endif Complex.cpp #include <iostream> #include "Complex.h" using namespace std; // Constructor Complex::Complex(double realPart, double imaginaryPart) : real(realPart), imaginary(imaginaryPart) { } // addition operator Complex Complex::operator+(const Complex &operand2) const { return Complex(real + operand2.real, imaginary + operand2.imaginary); } // subtraction operator Complex Complex::operator-(const Complex &operand2) const { return Complex(real - operand2.real, imaginary - operand2.imaginary); } // Overload << operator ostream &Complex::operator<<(ostream &output, const Complex &complexObj) const { cout << '(' << complexObj.real << ", " << complexObj.imaginary << ')'; return output; // returning output allows chaining } // display a Complex object in the form: (a, b) void Complex::print() const { cout << '(' << real << ", " << imaginary << ')'; } main.cpp #include <iostream> #include "Complex.h" using namespace std; int main() { Complex x; Complex y(4.3, 8.2); Complex z(3.3, 1.1); cout << "x: "; x.print(); cout << "\ny: "; y.print(); cout << "\nz: "; z.print(); x = y + z; cout << "\n\nx = y + z: " << endl; x.print(); cout << " = "; y.print(); cout << " + "; z.print(); x = y - z; cout << "\n\nx = y - z: " << endl; x.print(); cout << " = "; y.print(); cout << " - "; z.print(); cout << endl; } Compile erros: complex.cpp(23) : error C2039: '<<' : is not a member of 'Complex' complex.h(5) : see declaration of 'Complex' complex.cpp(24) : error C2270: '<<' : modifiers not allowed on nonmember functions complex.cpp(25) : error C2248: 'Complex::real' : cannot access private member declared in class 'Complex' complex.h(13) : see declaration of 'Complex::real' complex.h(5) : see declaration of 'Complex' complex.cpp(25) : error C2248: 'Complex::imaginary' : cannot access private member declared in class 'Complex' complex.h(14) : see declaration of 'Complex::imaginary' complex.h(5) : see declaration of 'Complex' Thanks!

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  • Temporary "Backup" of SharePoint Content During Feature and Solution Deployment

    - by ccomet
    I need to decide on a method for storing a subset of the content in a SharePoint site, so that when I delete and recreate certain lists as part of a feature activation, I can re-insert all of this content back where it should belong. I have an idea myself, but I don't know if it's the only method and more importantly, the right method. My client has me creating a SharePoint system for them to communicate with their clients. The business process has maybe 5 stages in it (maybe it's more, I don't even know because they don't tell me everything), and the current system I've written over the past months is maybe 2 stages through. This meets our deadline of completing those systems by Monday next week... but at that point my client is planning on making the site live from that point. In effect, their work with their clients will be running parallel with my work for them. As I complete my own work on a separate test server, I'll push each following stage of the process onto the live server. Scheduled downtimes during non-business times (like a weekend) will be available for me to perform these pushes. Keeping pace so that my development is faster than the actual business process is my own problem and off-topic... so let's get back to the problem I stated at the start of this post. In this system, we have sets of features which will create lists for their associated content types and field types when activated, and delete these lists when the feature is deactivated. Most updates don't need to deactivate and reactivate these features, such as workflow changes, custom actions, custom forms, and similar ilk. But there are some parts which do require this. On my test server, it's okay for me to obliterate lists, but once the site is live and there's real correspondence data, it's absolutely unacceptable to do this. So when I need to implement a new change in functionality, I need to be able to store the currently present data in several lists, deactivate the feature, reactivate the feature, and restore all of this data. Perhaps I have hoist myself by my own petard with the feature system I implemented. Unfortunately, the necessity to later on make several of these "project sites" meant I had to do a lot of my code with the concept of "Can be deployed repeatedly" in mind. My current plan is to run through lists and libraries which will be affected by the particular feature that is to be reset. Files and all of their versions will be saved in a directory on the server. Then, a set of text files will be used to store all of the important field values for the items. This includes a lot of cross-list reference lookups that will need to be maintained, but that's simple enough. Then, I deactivate the feature, deploy the new solution, and reactivate the feature. We upload all of the files in the order specified by their versions and update them with the stored fields for those versions, so that we retain the version structure. As each one is first uploaded, the new ID is picked out, and all relevant lookups in the rest of the files are updated (in some manner that I make sure I don't re-update it later with an incorrect value, of course). After that, we run through all the rest of the items in the order most conducive to keeping the relational data correct. This roughly summarizes what my current plan is. To my advantage, there are no long running workflows in the system that will be affected by this, so there's nothing I will have to worry about making sure nothing is "still running" when I do this stuff. I don't really know all the cons of this approach... I can imagine they're quite hefty. But I'm unsure what other choices I even have, and my searches haven't turned up anything. Is there anyone who can think of a better idea? Or will anyone just tell me that I really have no other choice? Thanks in advance!

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  • I create a JPanel and GridBagLayout within an object but when I get it in the main object, attributes are missing

    - by chickeneaterguy
    public oijoij() { String name = "Jackie"; int priority = 50; int minPriority = 90; setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setBounds(100, 100, 450, 300); contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); contentPane.setLayout(new BorderLayout(0, 0)); setContentPane(contentPane); JPanel panel = new JPanel(); GridBagLayout gbc_panel = new GridBagLayout(); gbc_panel.columnWidths = new int[]{0,0,0}; gbc_panel.rowHeights = new int[]{0, 0, 0, 0, 0, 0}; gbc_panel.columnWeights = new double[]{0.0, 0.0, Double.MIN_VALUE}; gbc_panel.rowWeights = new double[]{0.0, 0.0, 0.0, 0.0, 0.0, Double.MIN_VALUE}; panel.setBorder(new LineBorder(new Color(0,0,0),1)); panel.setLayout(gbc_panel); panel.setAlignmentX(Component.LEFT_ALIGNMENT); panel.setMinimumSize(new Dimension(110,110)); panel.setPreferredSize(new Dimension(110, 110)); panel.setSize(new Dimension(110,110)); JLabel lblNewLabel = new JLabel("Process ID:"); GridBagConstraints gbc_lblNewLabel = new GridBagConstraints(); gbc_lblNewLabel.gridheight = 2; gbc_lblNewLabel.insets = new Insets(0, 0, 5, 5); gbc_lblNewLabel.gridx = 0; gbc_lblNewLabel.gridy = 0; panel.add(lblNewLabel, gbc_lblNewLabel); JLabel lblNewLabel_1 = new JLabel(name); GridBagConstraints gbc_lblNewLabel_1 = new GridBagConstraints(); gbc_lblNewLabel_1.gridheight = 2; gbc_lblNewLabel_1.insets = new Insets(0, 0, 5, 0); gbc_lblNewLabel_1.gridx = 1; gbc_lblNewLabel_1.gridy = 0; panel.add(lblNewLabel_1, gbc_lblNewLabel_1); JLabel lblNewLabel_2 = new JLabel("Priority:"); GridBagConstraints gbc_lblNewLabel_2 = new GridBagConstraints(); gbc_lblNewLabel_2.insets = new Insets(0, 0, 5, 5); gbc_lblNewLabel_2.gridx = 0; gbc_lblNewLabel_2.gridy = 2; panel.add(lblNewLabel_2, gbc_lblNewLabel_2); JLabel lblNum = new JLabel(Integer.toString(priority)); GridBagConstraints gbc_lblNum = new GridBagConstraints(); gbc_lblNum.insets = new Insets(0, 0, 5, 0); gbc_lblNum.gridx = 1; gbc_lblNum.gridy = 2; panel.add(lblNum, gbc_lblNum); JLabel lblNewLabel_3 = new JLabel("Min Priority:"); GridBagConstraints gbc_lblNewLabel_3 = new GridBagConstraints(); gbc_lblNewLabel_3.insets = new Insets(0, 0, 5, 5); gbc_lblNewLabel_3.gridx = 0; gbc_lblNewLabel_3.gridy = 3; panel.add(lblNewLabel_3, gbc_lblNewLabel_3); JLabel lblMp = new JLabel(Integer.toString(minPriority)); GridBagConstraints gbc_lblMp = new GridBagConstraints(); gbc_lblMp.insets = new Insets(0, 0, 5, 0); gbc_lblMp.gridx = 1; gbc_lblMp.gridy = 3; panel.add(lblMp, gbc_lblMp); JLabel lblTimeSlice = new JLabel("Time Slice:"); GridBagConstraints gbc_lblTimeSlice = new GridBagConstraints(); gbc_lblTimeSlice.insets = new Insets(0, 0, 0, 5); gbc_lblTimeSlice.gridx = 0; gbc_lblTimeSlice.gridy = 4; panel.add(lblTimeSlice, gbc_lblTimeSlice); Random r = new Random(System.currentTimeMillis()); panel.setBackground(new Color( r.nextInt(255 - 210) + 210, r.nextInt(255 - 210) + 210, r.nextInt(255 - 210) + 210)); } I have accessor methods for the GridBagLayout and the JPanel. When calling the functions in another file, it looks like I just get the JPanel (but without any labels or the layout or other GridBagLayout features). Help?

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  • Lock-Free, Wait-Free and Wait-freedom algorithms for non-blocking multi-thread synchronization.

    - by GJ
    In multi thread programming we can find different terms for data transfer synchronization between two or more threads/tasks. When exactly we can say that some algorithem is: 1)Lock-Free 2)Wait-Free 3)Wait-Freedom I understand what means Lock-free but when we can say that some synchronization algorithm is Wait-Free or Wait-Freedom? I have made some code (ring buffer) for multi-thread synchronization and it use Lock-Free methods but: 1) Algorithm predicts maximum execution time of this routine. 2) Therad which call this routine at beginning set unique reference, what mean that is inside of this routine. 3) Other threads which are calling the same routine check this reference and if is set than count the CPU tick count (measure time) of first involved thread. If that time is to long interrupt the current work of involved thread and overrides him job. 4) Thread which not finished job because was interrupted from task scheduler (is reposed) at the end check the reference if not belongs to him repeat the job again. So this algorithm is not really Lock-free but there is no memory lock in use, and other involved threads can wait (or not) certain time before overide the job of reposed thread. Added RingBuffer.InsertLeft function: function TgjRingBuffer.InsertLeft(const link: pointer): integer; var AtStartReference: cardinal; CPUTimeStamp : int64; CurrentLeft : pointer; CurrentReference: cardinal; NewLeft : PReferencedPtr; Reference : cardinal; label TryAgain; begin Reference := GetThreadId + 1; //Reference.bit0 := 1 with rbRingBuffer^ do begin TryAgain: //Set Left.Reference with respect to all other cores :) CPUTimeStamp := GetCPUTimeStamp + LoopTicks; AtStartReference := Left.Reference OR 1; //Reference.bit0 := 1 repeat CurrentReference := Left.Reference; until (CurrentReference AND 1 = 0)or (GetCPUTimeStamp - CPUTimeStamp > 0); //No threads present in ring buffer or current thread timeout if ((CurrentReference AND 1 <> 0) and (AtStartReference <> CurrentReference)) or not CAS32(CurrentReference, Reference, Left.Reference) then goto TryAgain; //Calculate RingBuffer NewLeft address CurrentLeft := Left.Link; NewLeft := pointer(cardinal(CurrentLeft) - SizeOf(TReferencedPtr)); if cardinal(NewLeft) < cardinal(@Buffer) then NewLeft := EndBuffer; //Calcolate distance result := integer(Right.Link) - Integer(NewLeft); //Check buffer full if result = 0 then //Clear Reference if task still own reference if CAS32(Reference, 0, Left.Reference) then Exit else goto TryAgain; //Set NewLeft.Reference NewLeft^.Reference := Reference; SFence; //Try to set link and try to exchange NewLeft and clear Reference if task own reference if (Reference <> Left.Reference) or not CAS64(NewLeft^.Link, Reference, link, Reference, NewLeft^) or not CAS64(CurrentLeft, Reference, NewLeft, 0, Left) then goto TryAgain; //Calcolate result if result < 0 then result := Length - integer(cardinal(not Result) div SizeOf(TReferencedPtr)) else result := cardinal(result) div SizeOf(TReferencedPtr); end; //with end; { TgjRingBuffer.InsertLeft } RingBuffer unit you can find here: RingBuffer, CAS functions: FockFreePrimitives, and test program: RingBufferFlowTest Thanks in advance, GJ

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  • Writing a code example

    - by Stefano Borini
    I would like to have your feedback regarding code examples. One of the most frustrating experiences I sometimes have when learning a new technology is finding useless examples. I think an example as the most precious thing that comes with a new library, language, or technology. It must be a starting point, a wise and unadulterated explanation on how to achieve a given result. A perfect example must have the following characteristics: Self contained: it should be small enough to be compiled or executed as a single program, without dependencies or complex makefiles. An example is also a strong functional test if you correctly installed the new technology. The more issues could arise, the more likely is that something goes wrong, and the more difficult is to debug and solve the situation. Pertinent: it should demonstrate one, and only one, specific feature of your software/library, involving the minimal additional behavior from external libraries. Helpful: the code should bring you forward, step by step, using comments or self-documenting code. Extensible: the example code should be a small “framework” or blueprint for additional tinkering. A learner can start by adding features to this blueprint. Recyclable: it should be possible to extract parts of the example to use in your own code Easy: An example code is not the place to show your code-fu skillz. Keep it easy. helpful acronym: SPHERE. Prototypical examples of violations of those rules are the following: Violation of self-containedness: an example spanning multiple files without any real need for it. If your example is a python program, keep everything into a single module file. Don’t sub-modularize it. In Java, try to keep everything into a single class, unless you really must partition some entity into a meaningful object you need to pass around (and java mandates one class per file, if I remember correctly). Violation of Pertinency: When showing how many different shapes you can draw, adding radio buttons and complex controls with all the possible choices for point shapes is a bad idea. You de-focalize your example code, introducing code for event handling, controls initialization etc., and this is not part the feature you want to demonstrate, they are unnecessary noise in the understanding of the crucial mechanisms providing the feature. Violation of Helpfulness: code containing dubious naming, wrong comments, hacks, and functions longer than one page of code. Violation of Extensibility: badly factored code that have everything into a single function, with potentially swappable entities embedded within the code. Example: if an example reads data from a file and displays it, create a method getData() returning a useful entity, instead of opening the file raw and plotting the stuff. This way, if the user of the library needs to read data from a HTTP server instead, he just has to modify the getData() module and use the example almost as-is. Another violation of Extensibility comes if the example code is not under a fully liberal (e.g. MIT or BSD) license. Violation of Recyclability: when the code layout is so intermingled that is difficult to easily copy and paste parts of it and recycle them into another program. Again, licensing is also a factor. Violation of Easiness: Yes, you are a functional-programming nerd and want to show how cool you are by doing everything on a single line of map, filter and so on, but that could not be helpful to someone else, who is already under pressure to understand your library, and now has to understand your code as well. And in general, the final rule: if it takes more than 10 minutes to do the following: compile the code, run it, read the source, and understand it fully, it means that the example is not a good one. Please let me know your opinion, either positive or negative, or experience on this regard.

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  • Grafting LINQ onto C# 2 library

    - by P Daddy
    I'm writing a data access layer. It will have C# 2 and C# 3 clients, so I'm compiling against the 2.0 framework. Although encouraging the use of stored procedures, I'm still trying to provide a fairly complete ability to perform ad-hoc queries. I have this working fairly well, already. For the convenience of C# 3 clients, I'm trying to provide as much compatibility with LINQ query syntax as I can. Jon Skeet noticed that LINQ query expressions are duck typed, so I don't have to have an IQueryable and IQueryProvider (or IEnumerable<T>) to use them. I just have to provide methods with the correct signatures. So I got Select, Where, OrderBy, OrderByDescending, ThenBy, and ThenByDescending working. Where I need help are with Join and GroupJoin. I've got them working, but only for one join. A brief compilable example of what I have is this: // .NET 2.0 doesn't define the Func<...> delegates, so let's define some workalikes delegate TResult FakeFunc<T, TResult>(T arg); delegate TResult FakeFunc<T1, T2, TResult>(T1 arg1, T2 arg2); abstract class Projection{ public static Condition operator==(Projection a, Projection b){ return new EqualsCondition(a, b); } public static Condition operator!=(Projection a, Projection b){ throw new NotImplementedException(); } } class ColumnProjection : Projection{ readonly Table table; readonly string columnName; public ColumnProjection(Table table, string columnName){ this.table = table; this.columnName = columnName; } } abstract class Condition{} class EqualsCondition : Condition{ readonly Projection a; readonly Projection b; public EqualsCondition(Projection a, Projection b){ this.a = a; this.b = b; } } class TableView{ readonly Table table; readonly Projection[] projections; public TableView(Table table, Projection[] projections){ this.table = table; this.projections = projections; } } class Table{ public Projection this[string columnName]{ get{return new ColumnProjection(this, columnName);} } public TableView Select(params Projection[] projections){ return new TableView(this, projections); } public TableView Select(FakeFunc<Table, Projection[]> projections){ return new TableView(this, projections(this)); } public Table Join(Table other, Condition condition){ return new JoinedTable(this, other, condition); } public TableView Join(Table inner, FakeFunc<Table, Projection> outerKeySelector, FakeFunc<Table, Projection> innerKeySelector, FakeFunc<Table, Table, Projection[]> resultSelector){ Table join = new JoinedTable(this, inner, new EqualsCondition(outerKeySelector(this), innerKeySelector(inner))); return join.Select(resultSelector(this, inner)); } } class JoinedTable : Table{ readonly Table left; readonly Table right; readonly Condition condition; public JoinedTable(Table left, Table right, Condition condition){ this.left = left; this.right = right; this.condition = condition; } } This allows me to use a fairly decent syntax in C# 2: Table table1 = new Table(); Table table2 = new Table(); TableView result = table1 .Join(table2, table1["ID"] == table2["ID"]) .Select(table1["ID"], table2["Description"]); But an even nicer syntax in C# 3: TableView result = from t1 in table1 join t2 in table2 on t1["ID"] equals t2["ID"] select new[]{t1["ID"], t2["Description"]}; This works well and gives me identical results to the first case. The problem is if I want to join in a third table. TableView result = from t1 in table1 join t2 in table2 on t1["ID"] equals t2["ID"] join t3 in table3 on t1["ID"] equals t3["ID"] select new[]{t1["ID"], t2["Description"], t3["Foo"]}; Now I get an error (Cannot implicitly convert type 'AnonymousType#1' to 'Projection[]'), presumably because the second join is trying to join the third table to an anonymous type containing the first two tables. This anonymous type, of course, doesn't have a Join method. Any hints on how I can do this?

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  • how to get vendor id and product id of a plugged usb device on windows

    - by new
    Hello all, I am using Qt on windows platform. i want to get and display vendor id and product id of a plugged usb device from my local system. Below is my full source code to get the vendor id and product id from the usb device. when i run the my qt application it does not throw me any errors . so i plug the usb device into the system. but my print statement displays the result as below qDebug ()<DevicePath; i get the result as 0x4 Whether i have any implementation mistakes in my source code ? if so please guide me what i am doing wrong.. Have i missed out any other functions ? Is it possible to get the vendor id and product id from the usb device based on my source code .( my implementation of the code ) ? kindly find my source code below static GUID GUID_DEVINTERFACE_USB_DEVICE = { 0xA5DCBF10L, 0x6530, 0x11D2, { 0x90, 0x1F, 0x00, 0xC0, 0x4F, 0xB9, 0x51, 0xED } }; HANDLE hInfo = SetupDiGetClassDevs(&GUID_DEVINTERFACE_USB_DEVICE,NULL,NULL,DIGCF_PRESENT | DIGCF_INTERFACEDEVICE); if ( hInfo == INVALID_HANDLE_VALUE ) { qDebug ()<<"invalid"; } else { qDebug ()<<"valid handle"; SP_DEVINFO_DATA DeviceInfoData; DeviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA); SP_INTERFACE_DEVICE_DATA Interface_Info; Interface_Info.cbSize = sizeof(Interface_Info); BYTE Buf[1024]; DWORD i; DWORD InterfaceNumber= 0; PSP_DEVICE_INTERFACE_DETAIL_DATA pspdidd = (PSP_DEVICE_INTERFACE_DETAIL_DATA)Buf; for (i=0;SetupDiEnumDeviceInfo(hInfo,i,&DeviceInfoData);i++) { DWORD DataT; LPTSTR buffer = NULL; DWORD buffersize = 0; while (!SetupDiGetDeviceRegistryProperty( hInfo,&DeviceInfoData,SPDRP_DEVICEDESC,&DataT,(PBYTE)buffer,buffersize,&buffersize)) { if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) { // Change the buffer size. if (buffer) LocalFree(buffer); buffer = (LPTSTR)LocalAlloc(LPTR,buffersize); } else { // Insert error handling here. break; } qDebug ()<<(TEXT("Device Number %i is: %s\n"),i, buffer); if (buffer) LocalFree(buffer); if ( GetLastError()!=NO_ERROR && GetLastError()!=ERROR_NO_MORE_ITEMS ) { // Insert error handling here. qDebug ()<<"return false"; } InterfaceNumber = 0; // this just returns the first one, you can iterate on this if (SetupDiEnumDeviceInterfaces(hInfo,NULL,&GUID_DEVINTERFACE_USB_DEVICE,InterfaceNumber,&Interface_Info)) { printf("Got interface"); DWORD needed; pspdidd->cbSize = sizeof(*pspdidd); SP_DEVICE_INTERFACE_DETAIL_DATA *pDetData = NULL; DWORD dwDetDataSize = sizeof (SP_DEVICE_INTERFACE_DETAIL_DATA) + 256; SetupDiGetDeviceInterfaceDetail(hInfo, &Interface_Info, pDetData,dwDetDataSize, NULL,&DeviceInfoData); qDebug ()<<pDetData->DevicePath; //qDebug ()<<QString::fromWCharArray(pDetData->DevicePath); } else { printf("\nNo interface"); //ErrorExit((LPTSTR) "SetupDiEnumDeviceInterfaces"); if ( GetLastError() == ERROR_NO_MORE_ITEMS) printf(", since there are no more items found."); else printf(", unknown reason."); } // Cleanup SetupDiDestroyDeviceInfoList(hInfo); qDebug ()<<"return true"; } } }

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  • Looking for a better design: A readonly in-memory cache mechanism

    - by Dylan Lin
    Hi all, I have a Category entity (class), which has zero or one parent Category and many child Categories -- it's a tree structure. The Category data is stored in a RDBMS, so for better performance, I want to load all categories and cache them in memory while launching the applicaiton. Our system can have plugins, and we allow the plugin authors to access the Category Tree, but they should not modify the cached items and the tree(I think a non-readonly design might cause some subtle bugs in this senario), only the system knows when and how to refresh the tree. Here are some demo codes: public interface ITreeNode<T> where T : ITreeNode<T> { // No setter T Parent { get; } IEnumerable<T> ChildNodes { get; } } // This class is generated by O/R Mapping tool (e.g. Entity Framework) public class Category : EntityObject { public string Name { get; set; } } // Because Category is not stateless, so I create a cleaner view class for Category. // And this class is the Node Type of the Category Tree public class CategoryView : ITreeNode<CategoryView> { public string Name { get; private set; } #region ITreeNode Memebers public CategoryView Parent { get; private set; } private List<CategoryView> _childNodes; public IEnumerable<CategoryView> ChildNodes { return _childNodes; } #endregion public static CategoryView CreateFrom(Category category) { // here I can set the CategoryView.Name property } } So far so good. However, I want to make ITreeNode interface reuseable, and for some other types, the tree should not be readonly. We are not able to do this with the above readonly ITreeNode, so I want the ITreeNode to be like this: public interface ITreeNode<T> { // has setter T Parent { get; set; } // use ICollection<T> instead of IEnumerable<T> ICollection<T> ChildNodes { get; } } But if we make the ITreeNode writable, then we cannot make the Category Tree readonly, it's not good. So I think if we can do like this: public interface ITreeNode<T> { T Parent { get; } IEnumerable<T> ChildNodes { get; } } public interface IWritableTreeNode<T> : ITreeNode<T> { new T Parent { get; set; } new ICollection<T> ChildNodes { get; } } Is this good or bad? Are there some better designs? Thanks a lot! :)

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  • Problem with memset after an instance of a user defined class is created and a file is opened

    - by Liberalkid
    I'm having a weird problem with memset, that was something to do with a class I'm creating before it and a file I'm opening in the constructor. The class I'm working with normally reads in an array and transforms it into another array, but that's not important. The class I'm working with is: #include <vector> #include <algorithm> using namespace std; class PreProcess { public: PreProcess(char* fileName,char* outFileName); void SortedOrder(); private: vector< vector<double > > matrix; void SortRow(vector<double> &row); char* newFileName; vector< pair<double,int> > rowSorted; }; The other functions aren't important, because I've stopped calling them and the problem persists. Essentially I've narrowed it down to my constructor: PreProcess::PreProcess(char* fileName,char* outFileName):newFileName(outFileName){ ifstream input(fileName); input.close(); //this statement is inconsequential } I also read in the file in my constructor, but I've found that the problem persists if I don't read in the matrix and just open the file. Essentially I've narrowed it down to if I comment out those two lines the memset works properly, otherwise it doesn't. Now to the context of the problem I'm having with it: I wrote my own simple wrapper class for matrices. It doesn't have much functionality, I just need 2D arrays in the next part of my project and having a class handle everything makes more sense to me. The header file: #include <iostream> using namespace std; class Matrix{ public: Matrix(int r,int c); int &operator()(int i,int j) {//I know I should check my bounds here return matrix[i*columns+j]; } ~Matrix(); const void Display(); private: int *matrix; const int rows; const int columns; }; Driver: #include "Matrix.h" #include <string> using namespace std; Matrix::Matrix(int r,int c):rows(r),columns(c) { matrix=new int[rows*columns]; memset(matrix,0,sizeof(matrix)); } const void Matrix::Display(){ for(int i=0;i<rows;i++){ for(int j=0;j<columns;j++) cout << (*this)(i,j) << " "; cout << endl; } } Matrix::~Matrix() { delete matrix; } My main program runs: PreProcess test1(argv[1],argv[2]); //test1.SortedOrder(); Matrix test(10,10); test.Display(); And when I run this with the input line uncommented I get: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1371727776 32698 -1 0 0 0 0 0 6332656 0 -1 -1 0 0 6332672 0 0 0 0 0 0 0 0 0 0 0 0 0 -1371732704 32698 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I really don't have a clue what's going on in memory to cause this, on a side note if I replace memset with: for(int i=0;i<rows*columns;i++) *(matrix+i) &= 0x0; Then it works perfectly, it also works if I don't open the file. If it helps I'm running GCC 64-bit version 4.2.4 on Ubuntu.I assume there's some functionality of memset that I'm not properly understanding.

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  • Issues writing to serial port on MAC OSX using unistd.h in c

    - by Schuyler
    I am trying to write to a bluetooth device on MAC OSX using the unistd.h Linux functions in c. I am connecting fine and writing the first few bytes with success. When I try to write other commands to it (there are bytes added to the write buffer every 15ms), I don't see any results even though the write() function returns 1 (write success). If you start a write and it doesn't finish by the time you try to start another write (since it is non-blocking), could that possibly screw up the initial write? (If so, is there any way to check if a write has completed?) That is the only thing I can think of since the writes are occurring fairly frequently and the first two are successfully sent. qwbyte() simply adds a byte to the output array and increments its length The open port function: BAMid = -1; struct termios options; struct termios originalTTYAttrs; // Open the serial port read/write, nonblocking, with no controlling terminal, and don't wait for a connection. BAMid = open(strPath, O_RDWR | O_NOCTTY | O_NONBLOCK); if (BAMid == -1) { printf("Error opening serial port %s - %s(%d).\n", strPath, strerror(errno), errno); goto error; } // Issue TIOCEXCL ioctl to prevent additional opens except by root-owned processes. if (ioctl(BAMid, TIOCEXCL) == -1) { printf("Error setting TIOCEXCL on %s - %s(%d).\n", strPath, strerror(errno), errno); goto error; } // Get the current options and save them so we can restore the default settings later. if (tcgetattr(BAMid, &originalTTYAttrs) == -1) { printf("Error getting tty attributes %s - %s(%d).\n", strPath, strerror(errno), errno); goto error; } // The serial port attributes such as timeouts and baud rate are set by modifying the termios // structure and then calling tcsetattr() to cause the changes to take effect. Note that the // changes will not become effective without the tcsetattr() call. options = originalTTYAttrs; // Set raw input (non-canonical) mode, with reads blocking until either a single character // has been received or a one second timeout expires. [should be moot since we are leaving it as nonblocking] cfmakeraw(&options); options.c_cc[VMIN] = 1; options.c_cc[VTIME] = 10; cfsetspeed(&options, B57600); // Set 57600 baud options.c_cflag |= CS8; // Use 8 bit words // Cause the new options to take effect immediately. if (tcsetattr(BAMid, TCSANOW, &options) == -1) { printf("Error setting tty attributes %s - %s(%d).\n", strPath, strerror(errno), errno); goto error; } //flush old transmissions if (tcflush(BAMid,TCIOFLUSH) == -1) { printf("Error flushing BAM serial port - %s(%d).\n", strerror(errno), errno); } oBufLength = 0; // Ask it to start if (! qwbyte(CmdStart) ) { goto error; } if (! qwbyte(CmdFull) ) { goto error; } //this transmit works txbytes(); printf("success opening port!"); return -1; // Failure path error: if (BAMid != -1) { close(BAMid); } printf("returning an error--%d",errno); return errno; } The write function (txbytes): int i, bufSize, numBytes; if(oBufLength != 0) { //if the output array isn't empty //duplicating the output array and its size so it can //be overwritten while this write is occuring printf("about to transmit: "); for(i = 0; i < oBufLength; i++) { printf(" %u",oBuf[i]); tempBuf[i] = oBuf[i]; } printf("\n"); bufSize = oBufLength; oBufLength = 0; numBytes = write(BAMid, &tempBuf, bufSize); printf("bytes written = %d\n",numBytes); if (numBytes == -1) { printf("Error writing to port - %s(%d).\n", strerror(errno), errno); } return (numBytes 0); } else { return 0; }

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  • Issue with SPI (Serial Port Comm), stuck on ioctl()

    - by stef
    I'm trying to access a SPI sensor using the SPIDEV driver but my code gets stuck on IOCTL. I'm running embedded Linux on the SAM9X5EK (mounting AT91SAM9G25). The device is connected to SPI0. I enabled CONFIG_SPI_SPIDEV and CONFIG_SPI_ATMEL in menuconfig and added the proper code to the BSP file: static struct spi_board_info spidev_board_info[] { { .modalias = "spidev", .max_speed_hz = 1000000, .bus_num = 0, .chips_select = 0, .mode = SPI_MODE_3, }, ... }; spi_register_board_info(spidev_board_info, ARRAY_SIZE(spidev_board_info)); 1MHz is the maximum accepted by the sensor, I tried 500kHz but I get an error during Linux boot (too slow apparently). .bus_num and .chips_select should correct (I also tried all other combinations). SPI_MODE_3 I checked the datasheet for it. I get no error while booting and devices appear correctly as /dev/spidevX.X. I manage to open the file and obtain a valid file descriptor. I'm now trying to access the device with the following code (inspired by examples I found online). #define MY_SPIDEV_DELAY_USECS 100 // #define MY_SPIDEV_SPEED_HZ 1000000 #define MY_SPIDEV_BITS_PER_WORD 8 int spidevReadRegister(int fd, unsigned int num_out_bytes, unsigned char *out_buffer, unsigned int num_in_bytes, unsigned char *in_buffer) { struct spi_ioc_transfer mesg[2] = { {0}, }; uint8_t num_tr = 0; int ret; // Write data mesg[0].tx_buf = (unsigned long)out_buffer; mesg[0].rx_buf = (unsigned long)NULL; mesg[0].len = num_out_bytes; // mesg[0].delay_usecs = MY_SPIDEV_DELAY_USECS, // mesg[0].speed_hz = MY_SPIDEV_SPEED_HZ; mesg[0].bits_per_word = MY_SPIDEV_BITS_PER_WORD; mesg[0].cs_change = 0; num_tr++; // Read data mesg[1].tx_buf = (unsigned long)NULL; mesg[1].rx_buf = (unsigned long)in_buffer; mesg[1].len = num_in_bytes; // mesg[1].delay_usecs = MY_SPIDEV_DELAY_USECS, // mesg[1].speed_hz = MY_SPIDEV_SPEED_HZ; mesg[1].bits_per_word = MY_SPIDEV_BITS_PER_WORD; mesg[1].cs_change = 1; num_tr++; // Do the actual transmission if(num_tr > 0) { ret = ioctl(fd, SPI_IOC_MESSAGE(num_tr), mesg); if(ret == -1) { printf("Error: %d\n", errno); return -1; } } return 0; } Then I'm using this function: #define OPTICAL_SENSOR_ADDR "/dev/spidev0.0" ... int fd; fd = open(OPTICAL_SENSOR_ADDR, O_RDWR); if (fd<=0) { printf("Device not found\n"); exit(1); } uint8_t buffer1[1] = {0x3a}; uint8_t buffer2[1] = {0}; spidevReadRegister(fd, 1, buffer1, 1, buffer2); When I run it, the code get stuck on IOCTL! I did this way because, in order to read a register on the sensor, I need to send a byte with its address in it and then get the answer back without changing CS (however, when I tried using write() and read() functions, while learning, I got the same result, stuck on them). I'm aware that specifying .speed_hz causes a ENOPROTOOPT error on Atmel (I checked spidev.c) so I commented that part. Why does it get stuck? I though it can be as the device is created but it actually doesn't "feel" any hardware. As I wasn't sure if hardware SPI0 corresponded to bus_num 0 or 1, I tried both, but still no success (btw, which one is it?). UPDATE: I managed to have the SPI working! Half of it.. MOSI is transmitting the right data, but CLK doesn't start... any idea?

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  • Blackberry - application settings save/load

    - by Max Gontar
    Hi! I know two ways to save/load application settings: use PersistentStore use filesystem (store, since SDCard is optional) I'd like to know what are you're practicies of working with application settings? Using PersistentStore to save/load application settings The persistent store provides a means for objects to persist across device resets. A persistent object consists of a key-value pair. When a persistent object is committed to the persistent store, that object's value is stored in flash memory via a deep copy. The value can then be retrieved at a later point in time via the key. Example of helper class for storing and retrieving settings: class PSOptions { private PersistentObject mStore; private LongHashtableCollection mSettings; private long KEY_URL = 0; private long KEY_ENCRYPT = 1; private long KEY_REFRESH_PERIOD = 2; public PSOptions() { // "AppSettings" = 0x71f1f00b95850cfeL mStore = PersistentStore.getPersistentObject(0x71f1f00b95850cfeL); } public String getUrl() { Object result = get(KEY_URL); return (null != result) ? (String) result : null; } public void setUrl(String url) { set(KEY_URL, url); } public boolean getEncrypt() { Object result = get(KEY_ENCRYPT); return (null != result) ? ((Boolean) result).booleanValue() : false; } public void setEncrypt(boolean encrypt) { set(KEY_ENCRYPT, new Boolean(encrypt)); } public int getRefreshPeriod() { Object result = get(KEY_REFRESH_PERIOD); return (null != result) ? ((Integer) result).intValue() : -1; } public void setRefreshRate(int refreshRate) { set(KEY_REFRESH_PERIOD, new Integer(refreshRate)); } private void set(long key, Object value) { synchronized (mStore) { mSettings = (LongHashtableCollection) mStore.getContents(); if (null == mSettings) { mSettings = new LongHashtableCollection(); } mSettings.put(key, value); mStore.setContents(mSettings); mStore.commit(); } } private Object get(long key) { synchronized (mStore) { mSettings = (LongHashtableCollection) mStore.getContents(); if (null != mSettings && mSettings.size() != 0) { return mSettings.get(key); } else { return null; } } } } Example of use: class Scr extends MainScreen implements FieldChangeListener { PSOptions mOptions = new PSOptions(); BasicEditField mUrl = new BasicEditField("Url:", "http://stackoverflow.com/"); CheckboxField mEncrypt = new CheckboxField("Enable encrypt", false); GaugeField mRefresh = new GaugeField("Refresh period", 1, 60 * 10, 10, GaugeField.EDITABLE|FOCUSABLE); ButtonField mLoad = new ButtonField("Load settings", ButtonField.CONSUME_CLICK); ButtonField mSave = new ButtonField("Save settings", ButtonField.CONSUME_CLICK); public Scr() { add(mUrl); mUrl.setChangeListener(this); add(mEncrypt); mEncrypt.setChangeListener(this); add(mRefresh); mRefresh.setChangeListener(this); HorizontalFieldManager hfm = new HorizontalFieldManager(USE_ALL_WIDTH); add(hfm); hfm.add(mLoad); mLoad.setChangeListener(this); hfm.add(mSave); mSave.setChangeListener(this); loadSettings(); } public void fieldChanged(Field field, int context) { if (field == mLoad) { loadSettings(); } else if (field == mSave) { saveSettings(); } } private void saveSettings() { mOptions.setUrl(mUrl.getText()); mOptions.setEncrypt(mEncrypt.getChecked()); mOptions.setRefreshRate(mRefresh.getValue()); } private void loadSettings() { mUrl.setText(mOptions.getUrl()); mEncrypt.setChecked(mOptions.getEncrypt()); mRefresh.setValue(mOptions.getRefreshPeriod()); } }

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  • handling filename* parameters with spaces via RFC 5987 results in '+' in filenames

    - by Peter Friend
    I have some legacy code I am dealing with (so no I can't just use a URL with an encoded filename component) that allows a user to download a file from our website. Since our filenames are often in many different languages they are all stored as UTF-8. I wrote some code to handle the RFC5987 conversion to a proper filename* parameter. This works great until I have a filename with non-ascii characters and spaces. Per RFC, the space character is not part of attr_char so it gets encoded as %20. I have new versions of Chrome as well as Firefox and they are all converting to %20 to + on download. I have tried not encoding the space and putting the encoded filename in quotes and get the same result. I have sniffed the response coming from the server to verify that the servlet container wasn't mucking with my headers and they look correct to me. The RFC even has examples that contain %20. Am I missing something, or do all of these browsers have a bug related to this? Many thanks in advance. The code I use to encode the filename is below. Peter public static boolean bcsrch(final char[] chars, final char c) { final int len = chars.length; int base = 0; int last = len - 1; /* Last element in table */ int p; while (last >= base) { p = base + ((last - base) >> 1); if (c == chars[p]) return true; /* Key found */ else if (c < chars[p]) last = p - 1; else base = p + 1; } return false; /* Key not found */ } public static String rfc5987_encode(final String s) { final int len = s.length(); final StringBuilder sb = new StringBuilder(len << 1); final char[] digits = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'}; final char[] attr_char = {'!','#','$','&','\'','+','-','.','0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','^','_','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','|', '~'}; for (int i = 0; i < len; ++i) { final char c = s.charAt(i); if (bcsrch(attr_char, c)) sb.append(c); else { final char[] encoded = {'%', 0, 0}; encoded[1] = digits[0x0f & (c >>> 4)]; encoded[2] = digits[c & 0x0f]; sb.append(encoded); } } return sb.toString(); } Update Here is a screen shot of the download dialog I get for a file with Chinese characters with spaces as mentioned in my comment.

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  • How to have struct members accessible in different ways

    - by Paul J. Lucas
    I want to have a structure token that has start/end pairs for position, sentence, and paragraph information. I also want the members to be accessible in two different ways: as a start/end pair and individually. Given: struct token { struct start_end { int start; int end; }; start_end pos; start_end sent; start_end para; typedef start_end token::*start_end_ptr; }; I can write a function, say distance(), that computes the distance between any of the three start/end pairs like: int distance( token const &i, token const &j, token::start_end_ptr mbr ) { return (j.*mbr).start - (i.*mbr).end; } and call it like: token i, j; int d = distance( i, j, &token::pos ); that will return the distance of the pos pair. But I can also pass &token::sent or &token::para and it does what I want. Hence, the function is flexible. However, now I also want to write a function, say max(), that computes the maximum value of all the pos.start or all the pos.end or all the sent.start, etc. If I add: typedef int token::start_end::*int_ptr; I can write the function like: int max( list<token> const &l, token::int_ptr p ) { int m = numeric_limits<int>::min(); for ( list<token>::const_iterator i = l.begin(); i != l.end(); ++i ) { int n = (*i).pos.*p; // NOT WHAT I WANT: It hard-codes 'pos' if ( n > m ) m = n; } return m; } and call it like: list<token> l; l.push_back( i ); l.push_back( j ); int m = max( l, &token::start_end::start ); However, as indicated in the comment above, I do not want to hard-code pos. I want the flexibility of accessible the start or end of any of pos, sent, or para that will be passed as a parameter to max(). I've tried several things to get this to work (tried using unions, anonymous unions, etc.) but I can't come up with a data structure that allows the flexibility both ways while having each value stored only once. Any ideas how to organize the token struct so I can have what I want? Attempt at clarification Given struct of pairs of integers, I want to be able to "slice" the data in two distinct ways: By passing a pointer-to-member of a particular start/end pair so that the called function operates on any pair without knowing which pair. The caller decides which pair. By passing a pointer-to-member of a particular int (i.e., only one int of any pair) so that the called function operates on any int without knowing either which int or which pair said int is from. The caller decides which int of which pair. Another example for the latter would be to sum, say, all para.end or all sent.start. Also, and importantly: for #2 above, I'd ideally like to pass only a single pointer-to-member to reduce the burden on the caller. Hence, me trying to figure something out using unions.

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  • A RenderTargetView cannot be created from a NULL Resource

    - by numerical25
    I am trying to create my render target view but I get this error from direct X A RenderTargetView cannot be created from a NULL Resource To my knowledge it seems that I must fill the rendertarget pointer with data before passing it. But I am having trouble figure out how. Below is my declaration and implementation declaration #pragma once #include "stdafx.h" #include "resource.h" #include "d3d10.h" #include "d3dx10.h" #include "dinput.h" #define MAX_LOADSTRING 100 class RenderEngine { protected: RECT m_screenRect; //direct3d Members ID3D10Device *m_pDevice; // The IDirect3DDevice10 // interface ID3D10Texture2D *m_pBackBuffer; // Pointer to the back buffer ID3D10RenderTargetView *m_pRenderTargetView; // Pointer to render target view IDXGISwapChain *m_pSwapChain; // Pointer to the swap chain RECT m_rcScreenRect; // The dimensions of the screen ID3DX10Font *m_pFont; // The font used for rendering text // Sprites used to hold font characters ID3DX10Sprite *m_pFontSprite; ATOM RegisterEngineClass(); void Present(); public: static HINSTANCE m_hInst; HWND m_hWnd; int m_nCmdShow; TCHAR m_szTitle[MAX_LOADSTRING]; // The title bar text TCHAR m_szWindowClass[MAX_LOADSTRING]; // the main window class name void DrawTextString(int x, int y, D3DXCOLOR color, const TCHAR *strOutput); //static functions static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam); static INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam); bool InitWindow(); bool InitDirectX(); bool InitInstance(); int Run(); RenderEngine() { m_screenRect.right = 800; m_screenRect.bottom = 600; } }; my implementation bool RenderEngine::InitDirectX() { //potential error. You did not set to zero memory and you did not set the scaling property DXGI_MODE_DESC bd; bd.Width = m_screenRect.right; bd.Height = m_screenRect.bottom; bd.Format = DXGI_FORMAT_R8G8B8A8_UNORM; bd.RefreshRate.Numerator = 60; bd.RefreshRate.Denominator = 1; DXGI_SAMPLE_DESC sd; sd.Count = 1; sd.Quality = 0; DXGI_SWAP_CHAIN_DESC swapDesc; ZeroMemory(&swapDesc, sizeof(swapDesc)); swapDesc.BufferDesc = bd; swapDesc.SampleDesc = sd; swapDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT; swapDesc.OutputWindow = m_hWnd; swapDesc.BufferCount = 1; swapDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD, swapDesc.Windowed = true; swapDesc.Flags = 0; HRESULT hr; hr = D3D10CreateDeviceAndSwapChain(NULL, D3D10_DRIVER_TYPE_HARDWARE, NULL, D3D10_CREATE_DEVICE_DEBUG, D3D10_SDK_VERSION , &swapDesc, &m_pSwapChain, &m_pDevice); if(FAILED(hr)) return false; // Create a render target view hr = m_pDevice->CreateRenderTargetView( m_pBackBuffer, NULL, &m_pRenderTargetView); // FAILS RIGHT HERE // if(FAILED(hr)) return false; return true; }

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  • How can I implement the Gale-Shapley stable marriage algorithm in Perl?

    - by srk
    Problem : We have equal number of men and women.each men has a preference score toward each woman. So do the woman for each man. each of the men and women have certain interests. Based on the interest we calculate the preference scores. So initially we have an input in a file having x columns. First column is the person(men/woman) id. id are nothing but 0.. n numbers.(first half are men and next half woman) the remaining x-1 columns will have the interests. these are integers too. now using this n by x-1 matrix... we have come up with a n by n/2 matrix. the new matrix has all men and woman as their rows and scores for opposite sex in columns. We have to sort the scores in descending order, also we need to know the id of person related to the scores after sorting. So here i wanted to use hash table. once we get the scores we need to make up pairs.. for which we need to follow some rules. My trouble is with the second matrix of n by n/2 that needs to give information of which man/woman has how much preference on a woman/man. I need these scores sorted so that i know who is the first preferred woman/man, 2nd preferred and so on for a man/woman. I hope to get good suggestions on the data structures i use.. I prefer php or perl. Thank you in advance Hey guys this is not an home work. This a little modified version of stable marriage algorithm. I have working solution. I am only working on optimizing my code. more info: It is very similar to stable marriage problem but here we need to calculate the scores based on the interests they share. So i have implemented it as the way you see in the wiki page http://en.wikipedia.org/wiki/Stable_marriage_problem. my problem is not solving the problem. i solved it and can run it. I am just trying to have a better solution. so i am asking suggestions on the type of data structure to use. Conceptually I tried using an array of hashes. where the array index give the person id and the hash in it gives the id's <= score's in sorted manner. I initially start with an array of hashes. now i sort the hashes on values, but i could not store the sorted hashes back in an array.So just stored the keys after sorting and used these to get the values from my initial unsorted hashes. Can we store the hashes after sorting ? Can you suggest a better structure ?

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  • c - fork() and wait()

    - by Joe
    Hi there, I need to use the fork() and wait() functions to complete an assignment. We are modelling non-deterministic behaviour and need the program to fork() if there is more than one possible transition. In order to try and work out how fork and wait work, I have just made a simple program. I think I understand now how the calls work and would be fine if the program only branched once because the parent process could use the exit status from the single child process to determine whether the child process reached the accept state or not. As you can see from the code that follows though, I want to be able to handle situations where there must be more than one child processes. My problem is that you seem to only be able to set the status using an _exit function once. So, as in my example the exit status that the parent process tests for shows that the first child process issued 0 as it's exit status, but has no information on the second child process. I tried simply not _exit()-ing on a reject, but then that child process would carry on, and in effect there would seem to be two parent processes. Sorry for the waffle, but I would be grateful if someone could tell me how my parent process could obtain the status information on more than one child process, or I would be happy for the parent process to only notice accept status's from the child processes, but in that case I would successfully need to exit from the child processes which have a reject status. My test code is as follows: #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <errno.h> #include <sys/wait.h> int main(void) { pid_t child_pid, wpid, pid; int status = 0; int i; int a[3] = {1, 2, 1}; for(i = 1; i < 3; i++) { printf("i = %d\n", i); pid = getpid(); printf("pid after i = %d\n", pid); if((child_pid = fork()) == 0) { printf("In child process\n"); pid = getpid(); printf("pid in child process is %d\n", pid); /* Is a child process */ if(a[i] < 2) { printf("Should be accept\n"); _exit(1); } else { printf("Should be reject\n"); _exit(0); } } } if(child_pid > 0) { /* Is the parent process */ pid = getpid(); printf("parent_pid = %d\n", pid); wpid = wait(&status); if(wpid != -1) { printf("Child's exit status was %d\n", status); if(status > 0) { printf("Accept\n"); } else { printf("Complete parent process\n"); if(a[0] < 2) { printf("Accept\n"); } else { printf("Reject\n"); } } } } return 0; } Many thanks Joe

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  • Undefined referencec to ...

    - by Patrick LaChance
    I keep getting this error message every time I try to compile, and I cannot find out what the problem is. any help would be greatly appreciated: C:\DOCUME~1\Patrick\LOCALS~1\Temp/ccL92mj9.o:main.cpp:(.txt+0x184): undefined reference to 'List::List()' C:\DOCUME~1\Patrick\LOCALS~1\Temp/ccL92mj9.o:main.cpp:(.txt+0x184): undefined reference to 'List::add(int)' collect2: ld returned 1 exit status code: //List.h ifndef LIST_H define LIST_H include //brief Definition of linked list class class List { public: /** \brief Exception for operating on empty list */ class Empty : public std::exception { public: virtual const char* what() const throw(); }; /** \brief Exception for invalid operations other than operating on an empty list */ class InvalidOperation : public std::exception { public: virtual const char* what() const throw(); }; /** \brief Node within List */ class Node { public: /** data element stored in this node */ int element; /** next node in list / Node next; /** previous node in list / Node previous; Node (int element); ~Node(); void print() const; void printDebug() const; }; List(); ~List(); void add(int element); void remove(int element); int first()const; int last()const; int removeFirst(); int removeLast(); bool isEmpty()const; int size()const; void printForward() const; void printReverse() const; void printDebug() const; /** enables extra output for debugging purposes */ static bool traceOn; private: /** head of list */ Node* head; /** tail of list */ Node* tail; /** count of number of nodes */ int count; }; endif //List.cpp I only included the parts of List.cpp that might be the issue include "List.h" include include using namespace std; List::List() { //List::size = NULL; head = NULL; tail = NULL; } List::~List() { Node* current; while(head != NULL) { current = head- next; delete current-previous; if (current-next!=NULL) { head = current; } else { delete current; } } } void List::add(int element) { Node* newNode; Node* current; newNode-element = element; if(newNode-element head-element) { current = head-next; } else { head-previous = newNode; newNode-next = head; newNode-previous = NULL; return; } while(newNode-element current-element) { current = current-next; } if(newNode-element <= current-element) { newNode-previous = current-previous; newNode-next = current; } } //main.cpp include "List.h" include include using namespace std; //void add(int element); int main (char** argv, int argc) { List* MyList = new List(); bool quit = false; string value; int element; while(quit==false) { cinvalue; if(value == "add") { cinelement; MyList-add(element); } if(value=="quit") { quit = true; } } return 0; } I'm doing everything I think I'm suppose to be doing. main.cpp isn't complete yet, just trying to get the add function to work first. Any help will be greatly appreciated.

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  • Scrolling a canvas as a shape you're moving approaches its edges

    - by Steven Sproat
    Hi, I develop a Python-based drawing program, Whyteboard. I have tools that the user can create new shapes on the canvas, such as text/images/rectangles/circles/polygons. I also have a Select tool that allows the users to modify these shapes - for example, moving a shape's position, resizing, or editing polygon's points' positions. I'm adding in a new feature where moving or resizing a point near the canvas edge will automatically scroll the canvas. I think it's a good idea in terms of program usability, and annoys me when other program's don't have this feature. I've made some good progress on coding this; below is some Python code to demonstrate what I'm doing. These functions demonstrate how some shapes calculate their "edges": def find_edges(self): """A line.""" self.edges = {EDGE_TOP: min(self.y, self.y2), EDGE_RIGHT: max(self.x, self.x2), EDGE_BOTTOM: max(self.y, self.y2), EDGE_LEFT: min(self. x, self.x2)} def find_edges(self): """An image""" self.edges = {EDGE_TOP: self.y, EDGE_RIGHT: self.x + self.image.GetWidth(), EDGE_BOTTOM: self.y + self.image.GetWidth(), EDGE_LEFT: self.x} def find_edges(self): """Get the bounding rectangle for the polygon""" xmin = min(x for x, y in self.points) ymin = min(y for x, y in self.points) xmax = max(x for x, y in self.points) ymax = max(y for x, y in self.points) self.edges = {EDGE_TOP: ymin, EDGE_RIGHT: xmax, EDGE_BOTTOM: ymax, EDGE_LEFT: xmin} And here's the code I have so far to implement the scrolling when a shape nears the edge: def check_canvas_scroll(self, x, y, moving=False): """ We check that the x/y coords are within 50px from the edge of the canvas and scroll the canvas accordingly. If the shape is being moved, we need to check specific edges of the shape (e.g. left/right side of rectangle) """ size = self.board.GetClientSizeTuple() # visible area of the canvas if not self.board.area > size: # canvas is too small to need to scroll return start = self.board.GetViewStart() # user's starting "viewport" scroll = (-1, -1) # -1 means no change if moving: if self.shape.edges[EDGE_RIGHT] > start[0] + size[0] - 50: scroll = (start[0] + 5, -1) if self.shape.edges[EDGE_BOTTOM] > start[1] + size[1] - 50: scroll = (-1, start[1] + 5) # snip others else: if x > start[0] + size[0] - 50: scroll = (start[0] + 5, -1) if y > start[1] + size[1] - 50: scroll = (-1, start[1] + 5) # snip others self.board.Scroll(*scroll) This code actually works pretty well. If we're moving a shape, then we need to know its edges to calculate when they're coming close to the canvas edge. If we're resizing just a single point, then we just use the x/y coords of that point to see if it's close to the edge. The problem I'm having is a little tricky to describe - basically, if you move a shape to the left, and stop moving it, if you positioned the shape within the 50px from the canvas, then the next time you go to move the shape, the code that says "ok, is this shape close to the end?" gets triggered, and the canvas scrolls to the left, even if you're moving the shape to the right. Can anyone think on how to stop this? I created a youtube video to demonstrate the issue. At about 0:54, I move a polygon to the left of the canvas and position it there. The next time I move it, the canvas scrolls to the left even though I'm moving it right Another thing I'd like to add, but I'm stuck on is the scroll gaining momentum the longer a shape is scrolling? So, with a large canvas, you're not moving a shape for ages, moving 5px at a time, when you need to cover a 2000px distance. Any suggestions there? Thanks all - sorry for the super long question!

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  • C# SQLite file import prevent duplicates

    - by jakesankey
    Hi, I am attempting to get a directory (which is ever-growing) full of .txt comma delimited files to import into my SQLite db. I now have all of the files importing ok, however I need to have some way of excluding the files that have been previously added to db. I have a column in the db called FileName where the name and extension are stored next to each record from each file. Now I need to say 'If the code finds XXX.txt and XXX.txt is already in db, then skip this file'. Can I somehow add this logic to the getfiles command or is there another easy way? using (SQLiteCommand insertCommand = con.CreateCommand()) { SQLiteCommand cmdd = con.CreateCommand(); string[] files = Directory.GetFiles(@"C:\Documents and Settings\js91162\Desktop\", "R303717*.txt*", SearchOption.AllDirectories); foreach (string file in files) { string FileNameExt1 = Path.GetFileName(file); cmdd.CommandText = @" SELECT COUNT(*) FROM Import WHERE FileName = @FileExt;"; cmdd.Parameters.Add(new SQLiteParameter("@FileExt", FileNameExt1)); int count = Convert.ToInt32(cmdd.ExecuteScalar()); //int count = ((IConvertible)insertCommand.ExecuteScalar().ToInt32(null)); if (count == 0) { Console.WriteLine("Parsing CMM data for SQL database... Please wait."); insertCommand.CommandText = @" INSERT INTO Import (FeatType, FeatName, Value, Actual, Nominal, Dev, TolMin, TolPlus, OutOfTol, PartNumber, CMMNumber, Date, FileName) VALUES (@FeatType, @FeatName, @Value, @Actual, @Nominal, @Dev, @TolMin, @TolPlus, @OutOfTol, @PartNumber, @CMMNumber, @Date, @FileName);"; insertCommand.Parameters.Add(new SQLiteParameter("@FeatType", DbType.String)); insertCommand.Parameters.Add(new SQLiteParameter("@FeatName", DbType.String)); insertCommand.Parameters.Add(new SQLiteParameter("@Value", DbType.String)); insertCommand.Parameters.Add(new SQLiteParameter("@Actual", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@Nominal", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@Dev", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@TolMin", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@TolPlus", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@OutOfTol", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@Comment", DbType.String)); string FileNameExt = Path.GetFileName(file); string RNumber = Path.GetFileNameWithoutExtension(file); string RNumberE = RNumber.Split('_')[0]; string RNumberD = RNumber.Split('_')[1]; string RNumberDate = RNumber.Split('_')[2]; DateTime dateTime = DateTime.ParseExact(RNumberDate, "yyyyMMdd", Thread.CurrentThread.CurrentCulture); string cmmDate = dateTime.ToString("dd-MMM-yyyy"); string[] lines = File.ReadAllLines(file); bool parse = false; foreach (string tmpLine in lines) { string line = tmpLine.Trim(); if (!parse && line.StartsWith("Feat. Type,")) { parse = true; continue; } if (!parse || string.IsNullOrEmpty(line)) { continue; } Console.WriteLine(tmpLine); foreach (SQLiteParameter parameter in insertCommand.Parameters) { parameter.Value = null; } string[] values = line.Split(new[] { ',' }); for (int i = 0; i < values.Length - 1; i++) { SQLiteParameter param = insertCommand.Parameters[i]; if (param.DbType == DbType.Decimal) { decimal value; param.Value = decimal.TryParse(values[i], out value) ? value : 0; } else { param.Value = values[i]; } } insertCommand.Parameters.Add(new SQLiteParameter("@PartNumber", RNumberE)); insertCommand.Parameters.Add(new SQLiteParameter("@CMMNumber", RNumberD)); insertCommand.Parameters.Add(new SQLiteParameter("@Date", cmmDate)); insertCommand.Parameters.Add(new SQLiteParameter("@FileName", FileNameExt)); // insertCommand.ExecuteNonQuery(); } } } Console.WriteLine("CMM data successfully imported to SQL database..."); } con.Close(); }

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  • Template problems: No matching function for call

    - by Nick Sweet
    I'm trying to create a template class, and when I define a non-member template function, I get the "No matching function for call to randvec()" error. I have a template class defined as: template <class T> class Vector { T x, y, z; public: //constructors Vector(); Vector(const T& x, const T& y, const T& z); Vector(const Vector& u); //accessors T getx() const; T gety() const; T getz() const; //mutators void setx(const T& x); void sety(const T& y); void setz(const T& z); //operations void operator-(); Vector plus(const Vector& v); Vector minus(const Vector& v); Vector cross(const Vector& v); T dot(const Vector& v); void times(const T& s); T length() const; //Vector<T>& randvec(); //operators Vector& operator=(const Vector& rhs); friend std::ostream& operator<< <T>(std::ostream&, const Vector<T>&); }; and the function in question, which I've defined after all those functions above, is: //random Vector template <class T> Vector<double>& randvec() { const int min=-10, max=10; Vector<double>* r = new Vector<double>; int randx, randy, randz, temp; const int bucket_size = RAND_MAX/(max-min +1); temp = rand(); //voodoo hackery do randx = (rand()/bucket_size)+min; while (randx < min || randx > max); r->setx(randx); do randy = (rand()/bucket_size)+min; while (randy < min || randy > max); r->sety(randy); do randz = (rand()/bucket_size)+min; while (randz < min || randz > max); r->setz(randz); return *r; } Yet, every time I call it in my main function using a line like: Vector<double> a(randvec()); I get that error. However, if I remove the template and define it using 'double' instead of 'T', the call to randvec() works perfectly. Why doesn't it recognize randvec()? P.S. Don't mind the bit labeled voodoo hackery - this is just a cheap hack so that I can get around another problem I encountered.

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  • news feed using .Net Dataservices / OData / Atom ?

    - by Stephan
    Let's say I have an web CMS type application, and an EDM model with an entity called 'article', and I need to offer the ability for client applications, to a read/query the articles (and other resources stored in our database) a straightforward syndication feed of these articles to end users (along the lines of a simple RSS feed) It seems to me that for the first task, and .net 4's dataservice would be perfect for the job. For the second case, I'm wondering (a) whether atom the right format to choose - I think it is - and (b) whether it's possible to achieve such a feed using the same ado.net OData service. I took a look at some of the examples out there and briefly set up a proof of concept: http://localhost/projectname/DataService.svc/Articles <?xml version="1.0" encoding="utf-8" standalone="yes"?> <feed xml:base="http://localhost/projectname/DataService.svc/" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom"> <title type="text">Articles</title> <id>http://localhost/projectname/DataService.svc/Articles</id> <updated>2010-05-21T09:41:22Z</updated> <link rel="self" title="Articles" href="Articles" /> <entry> <id>http://---------DataService.svc/Articles(1)</id> <title type="text"></title> <updated>2010-05-21T09:41:22Z</updated> <author> <name /> </author> <link rel="edit" title="Article" href="Articles(1)" /> <category term="Model1.Article" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" /> <content type="application/xml"> <m:properties> <d:int_ContentID m:type="Edm.Int32">1</d:int_ContentID> <d:Titel>hello world</d:Titel> <d:Source>http://www.google.com</d:Source> </m:properties> </content> </entry> </feed> and noticed that, though the feed works and items are showing up, the title tag on the entry level is left blank. (as a result, when you check this feed in a feed reader, you will see no title). I searched msdn but haven't found a way to do that, but it should be possible. Stackoverflow itself uses an atom feed in that fashion, so it should be possible. Right? So I suppose my question is; Is there a way to make the ado.net dataservice Atom feed look like something suitable for your average news feed reader? - OR, am I using the wrong tool for the wrong purposes, and should I be looking elsewhere (.net syndication API's perhaps)?

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  • Sending changes from multiple tables in disconnected dataset to SQLServer...

    - by Stecy
    We have a third party application that accept calls using an XML RPC mechanism for calling stored procs. We send a ZIP-compressed dataset containing multiple tables with a bunch of update/delete/insert using this mechanism. On the other end, a CLR sproc decompress the data and gets the dataset. Then, the following code gets executed: using (var conn = new SqlConnection("context connection=true")) { if (conn.State == ConnectionState.Closed) conn.Open(); try { foreach (DataTable table in ds.Tables) { string columnList = ""; for (int i = 0; i < table.Columns.Count; i++) { if (i == 0) columnList = table.Columns[0].ColumnName; else columnList += "," + table.Columns[i].ColumnName; } var da = new SqlDataAdapter("SELECT " + columnList + " FROM " + table.TableName, conn); var builder = new SqlCommandBuilder(da); builder.ConflictOption = ConflictOption.OverwriteChanges; da.RowUpdating += onUpdatingRow; da.Update(ds, table.TableName); } } catch (....) { ..... } } Here's the event handler for the RowUpdating event: public static void onUpdatingRow(object sender, SqlRowUpdatingEventArgs e) { if ((e.StatementType == StatementType.Update) && (e.Command == null)) { e.Command = CreateUpdateCommand(e.Row, sender as SqlDataAdapter); e.Status = UpdateStatus.Continue; } } and the CreateUpdateCommand method: private static SqlCommand CreateUpdateCommand(DataRow row, SqlDataAdapter da) { string whereClause = ""; string setClause = ""; SqlConnection conn = da.SelectCommand.Connection; for (int i = 0; i < row.Table.Columns.Count; i++) { char quoted; if ((row.Table.Columns[i].DataType == Type.GetType("System.String")) || (row.Table.Columns[i].DataType == Type.GetType("System.DateTime"))) quoted = '\''; else quoted = ' '; string val = row[i].ToString(); if (row.Table.Columns[i].DataType == Type.GetType("System.Boolean")) val = (bool)row[i] ? "1" : "0"; bool isPrimaryKey = false; for (int j = 0; j < row.Table.PrimaryKey.Length; j++) { if (row.Table.PrimaryKey[j].ColumnName == row.Table.Columns[i].ColumnName) { if (whereClause != "") whereClause += " AND "; if (row[i] == DBNull.Value) whereClause += row.Table.Columns[i].ColumnName + "=NULL"; else whereClause += row.Table.Columns[i].ColumnName + "=" + quoted + val + quoted; isPrimaryKey = true; break; } } /* Only values for column that is not a primary key can be modified */ if (!isPrimaryKey) { if (setClause != "") setClause += ", "; if (row[i] == DBNull.Value) setClause += row.Table.Columns[i].ColumnName + "=NULL"; else setClause += row.Table.Columns[i].ColumnName + "=" + quoted + val + quoted; } } return new SqlCommand("UPDATE " + row.Table.TableName + " SET " + setClause + " WHERE " + whereClause, conn); } However, this is really slow when we have a lot of records. Is there a way to optimize this or an entirely different way to send lots of udpate/delete on several tables? I would really much like to use TSQL for this but can't figure a way to send a dataset to a regular sproc. Additional notes: We cannot directly access the SQLServer database. We tried without compression and it was slower.

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  • Someone please help google create instuctions that windows users understand. googles "instructions"

    - by nathan
    Below are the only instructions i managed to find from google on how to install the android NDK, it is written as if we all run Linux and presumes we all understand what these obscure tools are. My comments and questions appear in Italics if somone who knows unix and windows would translate for google that would be great! Android NDK Installation Introduction: Please read docs/OVERVIEW.TXT to understand what the Android NDK is and is not. This file gives instructions on how to properly setup your NDK. I. Requirements: The Android NDK currently requires a Linux, OS X or Windows host operating system. Windows users will need to install Cygwin (http://www.cygwin.com) to use it. Note that running the NDK under MSys is not supported. You will need to have the Android SDK and its dependencies installed. The NDK cannot generate final application packages (.apk files), only the shared library files that can go into them. IMPORTANT: The Android NDK can only be used to target system images using the Cupcake (1.5) or later releases of the platform. This is due to subtle toolchain and ABI related changed that make it incompatible with 1.0 and 1.1 system images. The NDK requires GNU Make 3.81 or later being available on your development system. Earlier versions of GNU Make might work but have not been tested. You can check this by running 'make -v' from the command-line. The output should look like: GNU Make 3.81 Copyright (C) 2006 Free Software Foundation, Inc. ... On certain systems, GNU Make might be available through a different command like 'gmake' or 'gnumake'. For these systems, replace 'make' by the appropriate command when invoking the NDK build system as described in the documentation. Great some strange thing called gnu make.. if your not going to tell me what it does maybe you then at least you could give me a URL to it? The NDK also requires a Nawk or GNU Awk executable being available on your development system. Note that the original 'awk' program doesn't implement the 'match' and 'substr' functions used by the NDK build system. Ok another tool, with 1 of 2 possible names, but not the third... and again where should i download this?? On Windows, you will need to install a recent release of Cygwin to use the NDK. See http://www.cygwin.com for instructions. Woohoo a URL! download took about a day because these install instructions do not specify what parts to download. II. Preparing your installation prebuilt cross-toolchain binaries: After installing and unarchiving the NDK, you will need to run the following command from the root folder: build/host-setup.sh hello? windows dont run nothing but .exe .com or .dll, just tell me how you want me to run it.. This will test your setup and make sure the NDK can work properly. Nothing is said about where any of these things need to be installed to (what directory)

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  • Problem exporting NSOpenGLView pixel data to some image file formats using ImageKit & CGImageDestina

    - by walkytalky
    I am developing an application to visualise some experimental data. One of its functions is to render the data in an NSOpenGLView subclass, and allow the resulting image to be exported to a file or copied to the clipboard. The view exports the data as an NSImage, generated like this: - (NSImage*) image { NSBitmapImageRep* imageRep; NSImage* image; NSSize viewSize = [self bounds].size; int width = viewSize.width; int height = viewSize.height; [self lockFocus]; [self drawRect:[self bounds]]; [self unlockFocus]; imageRep=[[[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL pixelsWide:width pixelsHigh:height bitsPerSample:8 samplesPerPixel:4 hasAlpha:YES isPlanar:NO colorSpaceName:NSDeviceRGBColorSpace bytesPerRow:width*4 bitsPerPixel:32] autorelease]; [[self openGLContext] makeCurrentContext]; glReadPixels(0,0,width,height,GL_RGBA,GL_UNSIGNED_BYTE,[imageRep bitmapData]); image=[[[NSImage alloc] initWithSize:NSMakeSize(width,height)] autorelease]; [image addRepresentation:imageRep]; [image setFlipped:YES]; // this is deprecated in 10.6 [image lockFocusOnRepresentation:imageRep]; // this will flip the rep [image unlockFocus]; return image; } Copying uses this image very simply, like this: - (IBAction) copy:(id) sender { NSImage* img = [self image]; NSPasteboard* pb = [NSPasteboard generalPasteboard]; [pb clearContents]; NSArray* copied = [NSArray arrayWithObject:img]; [pb writeObjects:copied]; } For file writing, I use the ImageKit IKSaveOptions accessory panel to set the output file type and associated options, then use the following code to do the writing: NSImage* glImage = [glView image]; NSRect rect = [glView bounds]; rect.origin.x = rect.origin.y = 0; img = [glImage CGImageForProposedRect:&rect context:[NSGraphicsContext currentContext] hints:nil]; if (img) { NSURL* url = [NSURL fileURLWithPath: path]; CGImageDestinationRef dest = CGImageDestinationCreateWithURL((CFURLRef)url, (CFStringRef)newUTType, 1, NULL); if (dest) { CGImageDestinationAddImage(dest, img, (CFDictionaryRef)[imgSaveOptions imageProperties]); CGImageDestinationFinalize(dest); CFRelease(dest); } } (I've trimmed a bit of extraneous code here, but nothing that would affect the outcome as far as I can see. The newUTType comes from the IKSaveOptions panel.) This works fine when the file is exported as GIF, JPEG, PNG, PSD or TIFF, but exporting to PDF, BMP, TGA, ICNS and JPEG-2000 produces a red colour artefact on part of the image. Example images are below, the first exported as JPG, the second as PDF. Copy to clipboard does not exhibit this red stripe with the current implementation of image, but it did with the original implementation, which generated the imageRep using NSCalibratedRGBColorSpace rather than NSDeviceRGBColorSpace. So I'm guessing there's some issue with the colour representation in the pixels I get from OpenGL that doesn't get through the subsequent conversions properly, but I'm at a loss as to what to do about it. So, can anyone tell me (i) what is causing this, and (ii) how can I make it go away? I don't care so much about all of the formats but I'd really like at least PDF to work.

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