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  • linking error in zxing while trying to use it in my project iphone

    - by Usman
    Hi, In My Project i need bar-code scanning. so i use zxing library but i m heaving some linking error and its getting me crazy. error is Undefined symbols: "zxing::BinaryBitmap::BinaryBitmap(zxing::Ref<zxing::Binarizer>)", referenced from: -[Decoder decode:] in Decoder.o "zxing::LuminanceSource::LuminanceSource()", referenced from: GrayBytesMonochromeBitmapSource::GrayBytesMonochromeBitmapSource(unsigned char const*, int, int, int)in GrayBytesMonochromeBitmapSource.o "zxing::qrcode::QRCodeReader::decode(zxing::Ref<zxing::BinaryBitmap>)", referenced from: -[Decoder decode:] in Decoder.o "zxing::LuminanceSource::~LuminanceSource()", referenced from: GrayBytesMonochromeBitmapSource::~GrayBytesMonochromeBitmapSource()in GrayBytesMonochromeBitmapSource.o GrayBytesMonochromeBitmapSource::~GrayBytesMonochromeBitmapSource()in GrayBytesMonochromeBitmapSource.o "zxing::ReaderException::~ReaderException()", referenced from: -[Decoder decode:] in Decoder.o -[Decoder decode:] in Decoder.o "zxing::String::getText()", referenced from: -[Decoder decode:] in Decoder.o "typeinfo for zxing::LuminanceSource", referenced from: typeinfo for GrayBytesMonochromeBitmapSourcein GrayBytesMonochromeBitmapSource.o "vtable for zxing::IllegalArgumentException", referenced from: __ZTVN5zxing24IllegalArgumentExceptionE$non_lazy_ptr in Decoder.o "typeinfo for zxing::ReaderException", referenced from: GCC_except_table1 in Decoder.o "vtable for zxing::Exception", referenced from: __ZTVN5zxing9ExceptionE$non_lazy_ptr in Decoder.o "zxing::LuminanceSource::copyMatrix()", referenced from: vtable for GrayBytesMonochromeBitmapSourcein GrayBytesMonochromeBitmapSource.o "zxing::Result::getText()", referenced from: -[Decoder decode:] in Decoder.o "zxing::GlobalHistogramBinarizer::GlobalHistogramBinarizer(zxing::Ref<zxing::LuminanceSource>)", referenced from: -[Decoder decode:] in Decoder.o "zxing::IllegalArgumentException::~IllegalArgumentException()", referenced from: -[Decoder decode:] in Decoder.o -[Decoder decode:] in Decoder.o "zxing::Result::getResultPoints()", referenced from: -[Decoder decode:] in Decoder.o "typeinfo for zxing::IllegalArgumentException", referenced from: GCC_except_table1 in Decoder.o "zxing::Exception::what() const", referenced from: -[Decoder decode:] in Decoder.o -[Decoder decode:] in Decoder.o "vtable for zxing::ReaderException", referenced from: __ZTVN5zxing15ReaderExceptionE$non_lazy_ptr in Decoder.o "zxing::qrcode::QRCodeReader::QRCodeReader()", referenced from: -[Decoder decode:] in Decoder.o "zxing::qrcode::QRCodeReader::~QRCodeReader()", referenced from: -[Decoder decode:] in Decoder.o -[Decoder decode:] in Decoder.o ld: symbol(s) not found collect2: ld returned 1 exit status "zxing::BinaryBitmap::BinaryBitmap(zxing::Ref<zxing::Binarizer>)", referenced from: -[Decoder decode:] in Decoder.o "zxing::LuminanceSource::LuminanceSource()", referenced from: GrayBytesMonochromeBitmapSource::GrayBytesMonochromeBitmapSource(unsigned char const*, int, int, int)in GrayBytesMonochromeBitmapSource.o "zxing::qrcode::QRCodeReader::decode(zxing::Ref<zxing::BinaryBitmap>)", referenced from: -[Decoder decode:] in Decoder.o "zxing::LuminanceSource::~LuminanceSource()", referenced from: GrayBytesMonochromeBitmapSource::~GrayBytesMonochromeBitmapSource()in GrayBytesMonochromeBitmapSource.o GrayBytesMonochromeBitmapSource::~GrayBytesMonochromeBitmapSource()in GrayBytesMonochromeBitmapSource.o "zxing::ReaderException::~ReaderException()", referenced from: -[Decoder decode:] in Decoder.o -[Decoder decode:] in Decoder.o "zxing::String::getText()", referenced from: -[Decoder decode:] in Decoder.o "typeinfo for zxing::LuminanceSource", referenced from: typeinfo for GrayBytesMonochromeBitmapSourcein GrayBytesMonochromeBitmapSource.o "vtable for zxing::IllegalArgumentException", referenced from: __ZTVN5zxing24IllegalArgumentExceptionE$non_lazy_ptr in Decoder.o "typeinfo for zxing::ReaderException", referenced from: GCC_except_table1 in Decoder.o "vtable for zxing::Exception", referenced from: __ZTVN5zxing9ExceptionE$non_lazy_ptr in Decoder.o "zxing::LuminanceSource::copyMatrix()", referenced from: vtable for GrayBytesMonochromeBitmapSourcein GrayBytesMonochromeBitmapSource.o "zxing::Result::getText()", referenced from: -[Decoder decode:] in Decoder.o "zxing::GlobalHistogramBinarizer::GlobalHistogramBinarizer(zxing::Ref<zxing::LuminanceSource>)", referenced from: -[Decoder decode:] in Decoder.o "zxing::IllegalArgumentException::~IllegalArgumentException()", referenced from: -[Decoder decode:] in Decoder.o -[Decoder decode:] in Decoder.o "zxing::Result::getResultPoints()", referenced from: -[Decoder decode:] in Decoder.o "typeinfo for zxing::IllegalArgumentException", referenced from: GCC_except_table1 in Decoder.o "zxing::Exception::what() const", referenced from: -[Decoder decode:] in Decoder.o -[Decoder decode:] in Decoder.o "vtable for zxing::ReaderException", referenced from: __ZTVN5zxing15ReaderExceptionE$non_lazy_ptr in Decoder.o "zxing::qrcode::QRCodeReader::QRCodeReader()", referenced from: -[Decoder decode:] in Decoder.o "zxing::qrcode::QRCodeReader::~QRCodeReader()", referenced from: -[Decoder decode:] in Decoder.o -[Decoder decode:] in Decoder.o ld: symbol(s) not found collect2: ld returned 1 exit status i m trying to resolve this for last two day. i think i m missing some library or some file. can any one point me out what i m doing wrong. Usman

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  • could I know which file is altered using fsevent?

    - by Frost Li
    I get the directory path from fsevent, such as "/User/Data/" But what I really want is "/User/Data/change.txt" I have read the programming guide, it said typedef void ( *FSEventStreamCallback )( ConstFSEventStreamRef streamRef, void *clientCallBackInfo, size_t numEvents, void *eventPaths, const FSEventStreamEventFlags eventFlags[], const FSEventStreamEventId eventIds[]); eventPaths An array of paths to the directories in which event(s) occurred. is there any method to find out which file is altered? thanks!!!! I have stuck to it for so long..

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  • How to use CWnd::CreateEx

    - by chitra
    I was using CreateEx( 0, className, "XXX", WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN, rect, parent, 0); in Visual C++ 6.0. when i port the same to VS 2008.., its giving an error message saying that.. error C2664: 'BOOL CWnd::CreateEx(DWORD,LPCTSTR,LPCTSTR,DWORD,const RECT &,CWnd *,UINT,LPVOID)' : cannot convert parameter 3 from 'const char [7]' to 'LPCTSTR' how to rectify the same thanks Chitra

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  • Specialization of template after instantiation?

    - by Onur Cobanoglu
    Hi, My full code is too long, but here is a snippet that will reflect the essence of my problem: class BPCFGParser { public: ... ... class Edge { ... ... }; class ActiveEquivClass { ... ... }; class PassiveEquivClass { ... ... }; struct EqActiveEquivClass { ... ... }; struct EqPassiveEquivClass { ... ... }; unordered_map<ActiveEquivClass, Edge *, hash<ActiveEquivClass>, EqActiveEquivClass> discovered_active_edges; unordered_map<PassiveEquivClass, Edge *, hash<PassiveEquivClass>, EqPassiveEquivClass> discovered_passive_edges; }; namespace std { template <> class hash<BPCFGParser::ActiveEquivClass> { public: size_t operator()(const BPCFGParser::ActiveEquivClass & aec) const { } }; template <> class hash<BPCFGParser::PassiveEquivClass> { public: size_t operator()(const BPCFGParser::PassiveEquivClass & pec) const { } }; } When I compile this code, I get the following errors: In file included from BPCFGParser.cpp:3, from experiments.cpp:2: BPCFGParser.h:408: error: specialization of ‘std::hash<BPCFGParser::ActiveEquivClass>’ after instantiation BPCFGParser.h:408: error: redefinition of ‘class std::hash<BPCFGParser::ActiveEquivClass>’ /usr/include/c++/4.3/tr1_impl/functional_hash.h:44: error: previous definition of ‘class std::hash<BPCFGParser::ActiveEquivClass>’ BPCFGParser.h:445: error: specialization of ‘std::hash<BPCFGParser::PassiveEquivClass>’ after instantiation BPCFGParser.h:445: error: redefinition of ‘class std::hash<BPCFGParser::PassiveEquivClass>’ /usr/include/c++/4.3/tr1_impl/functional_hash.h:44: error: previous definition of ‘class std::hash<BPCFGParser::PassiveEquivClass>’ Now I have to specialize std::hash for these classes (because standard std::hash definition does not include user defined types). When I move these template specializations before the definition of class BPCFGParser, I get a variety of errors for a variety of different things tried, and somewhere (http://www.parashift.com/c++-faq-lite/misc-technical-issues.html) I read that: Whenever you use a class as a template parameter, the declaration of that class must be complete and not simply forward declared. So I'm stuck. I cannot specialize the templates after BPCFGParser definition, I cannot specialize them before BPCFGParser definition, how may I get this working? Thanks in advance, Onur

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  • Accessing not Non-QObject-based objects from Qt Script

    - by uni
    Is there any nice and simple way to access non QObject-based classes, such as QXmlQuery, QDateTime etc. from Qt Script? The only way I see is to wrap QXmlQuery in another class that inherits QObject and declare as slot every function which I need to access from Qt Script: void MyXmlQuery::setQuery ( const QString & sourceCode, const QUrl & documentURI ) { realxmlquery_.setQuery(sourceCode, documentURI); }

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  • How to linebreak long string constructs ?

    - by iFloh
    I am editing SQLite SQL statements of substantial length. How can I break these into several lines to allow comfortablt editing? const char *sql = "SELECT arguments arguments arguments arguments arguments arguments arguments arguments arguments arguments FROM a, b, WHERE condition condition condition condition condition condition condition" into const char *sql = "SELECT arguments arguments arguments arguments arguments arguments arguments arguments arguments arguments FROM a, b WHERE condition condition condition" cheers

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  • integer constant does 'not reduce to an integer'

    - by Dan Morgan
    I use this code to set my constants // Constants.h extern NSInteger const KNameIndex; // Constants.m NSInteger const KNameIndex = 0; And in a switch statement within a file that imports the Constant.h file I have this: switch (self.sectionFromParentTable) { case KNameIndex: self.types = self.facilityTypes; break; ... I get error at compile that read this: "error:case label does not reduce to an integer constant" Any ideas what might be messed up?

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  • How to get MinValue/MaxValue of a certain ValueType via reflection?

    - by marco.ragogna
    I need to this at runtime. I checked using Reflector and value types line like Int16, for example, should contain <Serializable, StructLayout(LayoutKind.Sequential), ComVisible(True)> _ Public Structure Int16 Implements IComparable, IFormattable, IConvertible, IComparable(Of Short), IEquatable(Of Short) Public Const MaxValue As Short = &H7FFF Public Const MinValue As Short = -32768 End Structure But the following code is not working Dim dummyValue = Activator.CreateInstance(GetType(UInt16)) Dim minValue As IComparable = DirectCast(dummyValue.GetType.GetProperty("MinValue").GetValue(dummyValue, Nothing), IComparable) any idea how to solve?

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  • Inherited TShape.Paint does not work after overriding Shape property

    - by DarkWalker
    I'm to code a TExpandedShape class inherited from TShape. TExpandedShape must act like TShape and be able to draw extra shapes: Polygon and Star. Here is my code unit ExpandedShape; interface uses SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls, Windows; type TExpandedShapeType = ( stRectangle, stSquare, stRoundRect, stRoundSquare, stEllipse, stCircle, stPolygon, stStar ); TExpandedShape = class(TShape) private FShape: TExpandedShapeType; FEdgeCount: integer; procedure SetShape(const Value: TExpandedShapeType); procedure SetEdgeCount(const Value: integer); public procedure Paint; override; published property Shape : TExpandedShapeType read FShape write SetShape;// default stPolygon; property EdgeCount : integer read FEdgeCount write SetEdgeCount default 5; end; procedure Register; implementation procedure Register; begin RegisterComponents('Course', [TExpandedShape]); end; // TExpandedShape procedure TExpandedShape.Paint; begin case Shape of stStar : begin {Draw Star} end; stPolygon : begin {Draw Polygon} end; else begin {It is supposed to draw Circle, Rectangle etc, but it does not} inherited; end; end; end; procedure TExpandedShape.SetEdgeCount(const Value: integer); begin FEdgeCount := Value; Repaint; end; procedure TExpandedShape.SetShape(const Value: TExpandedShapeType); begin FShape := Value; Repaint; end; end. So, what is wrong? IMO TShape.Paint checks private value like FShape in case section and then decides what to draw. When inherited Paint method is called in my code it checks FShape value sees default 0 value [stRectangle] in there and draws it. PS: I did solve it with blackmagic way using Shape1 property instead of Shape one and if Shape1 value is not stPolygon or stStar i do like this: begin Shape := TShapeType(Shape1); inherited end; But this option is not really an option. I need a good short nice-looking one.

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  • How to declare NSString constants for passing to NSNotificationCenter

    - by synic
    I've got the following in my .h file: #ifndef _BALANCE_NOTIFICATION #define _BALANCE NOTIFICATION const NSString *BalanceUpdateNotification #endif and the following in my .m file: const NSString *BalanceUpdateNotification = @"BalanceUpdateNotification"; I'm using this with the following codes: [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateBalance:) name:BalanceUpdateNotification object:nil]; and [[NSNotificatoinCenter defaultCenter] postNotificationName:BalanceUpdateNotificatoin object:self userInfo:nil]; Which works, but it gives me a warning: Passing argument 1 of 'postNotificationName:object:userInfo' discards qualifiers from pointer target type So, I can cast it to (NSString *), but I'm wondering what the proper way to do this is.

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  • Inline instantiation of a constant List

    - by Roflcoptr
    I try to do something like this: public const List<String> METRICS = new List<String>() { SourceFile.LOC, SourceFile.MCCABE, SourceFile.NOM, SourceFile.NOA, SourceFile.FANOUT, SourceFile.FANIN, SourceFile.NOPAR, SourceFile.NDC, SourceFile.CALLS }; But unfortunately this doesn't work: FileStorer.METRICS' is of type 'System.Collections.Generic.List<string>'. A const field of a reference type other than string can only be initialized with null. How can I solve this problem?

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  • Qt double click check left button mouse

    - by Alex Ivasyuv
    I need to run slot only on doubleClick with left button mouse, instead of both. connect(this -> myComponent, SIGNAL (doubleClicked (const QModelIndex & )), this, SLOT (performSomeAction(const QModelIndex & ))); With this event, double click works in both cases, but needed only with left button click. How I can do it? this - myComponent = QTableView

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  • subclassing QList and operator+ overloading

    - by Milen
    I would like to be able to add two QList objects. For example: QList<int> b; b.append(10); b.append(20); b.append(30); QList<int> c; c.append(1); c.append(2); c.append(3); QList<int> d; d = b + c; For this reason, I decided to subclass the QList and to overload the operator+. Here is my code: class List : public QList<int> { public: List() : QList<int>() {} // Add QList + QList friend List operator+(const List& a1, const List& a2); }; List operator+(const List& a1, const List& a2) { List myList; myList.append(a1[0] + a2[0]); myList.append(a1[1] + a2[1]); myList.append(a1[2] + a2[2]); return myList; } int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); List b; b.append(10); b.append(20); b.append(30); List c; c.append(1); c.append(2); c.append(3); List d; d = b + c; List::iterator i; for(i = d.begin(); i != d.end(); ++i) qDebug() << *i; return a.exec(); } , the result is correct but I am not sure whether this is a good approach. I would like to ask whether there is better solution?

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  • How to create constant NSString by concatenating strings in Obj-C ?

    - by eric-morand
    Hi guys, I'm trying to instanciate a constant NSString by concatanating other NSString instances. Here is what I'm doing in my implementation file : static NSString *const MY_CONST = @"TEST"; static NSString *const MY_CONCATENATE_CONST = [NSString stringWithFormat:@"STRING %@", MY_CONST]; It leads to the following compilation error : Initializer element is not constant I suppose this is because stringWithFormat doesn't return a constant NSString, but since there is no other way to concatenate strings in Obj-C, what am I supposed to do ? Thanks for your help, Eric.

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  • Using a function with reference as a function with pointers?

    - by epatel
    Today I stumbled over a piece of code that looked horrifying to me. The pieces was chattered in different files, I have tried write the gist of it in a simple test case below. The code base is routinely scanned with FlexeLint on a daily basis, but this construct has been laying in the code since 2004. The thing is that a function implemented with a parameter passing using references is called as a function with a parameter passing using pointers...due to a function cast. The construct has worked since 2004 on Irix and now when porting it actually do work on Linux/gcc too. My question now. Is this a construct one can trust? I can understand if compiler constructors implement the reference passing as it was a pointer, but is it reliable? Are there hidden risks? Should I change the fref(..) to use pointers and risk braking anything in the process? What to you think? #include <iostream> using namespace std; // ---------------------------------------- // This will be passed as a reference in fref(..) struct string_struct { char str[256]; }; // ---------------------------------------- // Using pointer here! void fptr(const char *str) { cout << "fptr: " << str << endl; } // ---------------------------------------- // Using reference here! void fref(string_struct &str) { cout << "fref: " << str.str << endl; } // ---------------------------------------- // Cast to f(const char*) and call with pointer void ftest(void (*fin)()) { void (*fcall)(const char*) = (void(*)(const char*))fin; fcall("Hello!"); } // ---------------------------------------- // Let's go for a test int main() { ftest((void (*)())fptr); // test with fptr that's using pointer ftest((void (*)())fref); // test with fref that's using reference return 0; }

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  • How do I modify a HTTP response packet with winpcap?

    - by httpinterpret
    There are two problems here: What if content is encoded:gzip... Do I also need to change the header part to make the HTTP packet valid(checksums if any?) UPDATE Can someone with actual experience elaborate the steps involved? I'm using winpcap and bpf tcp and src port 80 to filter the traffic,so my job lies in this callback function: void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data)

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  • cannot delete from doubly linked list using visual studios in C

    - by Jesus Sanchez
    hello I am currently doing an assignment that is supposed to read in a file, use the information, and then print out another file. all using doubly linked list. Currently i am trying to just read in the file into a doubly linked list, print it out onto the screen and a file, and finally delete the list and close the program. The program works fine as long as I don't call the dlist_distroy function which is supposed to delete the string. as soon as I do it the program starts running and then a window pops up saying "Windows has triggered a breakpoint in tempfilter.exe. This may be due to a corruption of the heap, which indicates a bug in tempfilter.exe or any of the DLLs it has loaded. This may also be due to the user pressing F12 while tempfilter.exe has focus. The output window may have more diagnostic information." I have revised the destroy and remove functions and cant understand the problem. my program is the following main.c #include <stdlib.h> #include <stdio.h> #include <string.h> #include "dlinklist.h" #include "DlistElmt.h" #include "Dlist.h" #include "dlistdata.h" /**************************************************************************************************/ int main ( int argc, char *argv[] ) { FILE *ifp, *ofp; int hour, min; Dlist *list; DlistElmt *current=NULL, *element; float temp; list = (Dlist *)malloc(sizeof(list)); element = (DlistElmt *)malloc(sizeof(element)); if ( argc != 3 ) /* argc should be 3 for correct execution */ { /* We print argv[0] assuming it is the program name */ /* TODO: This is wrong, it should be: usage: %s inputfile outputfile */ printf( "usage: %s filename", argv[0] ); } else { // We assume argv[1] is a filename to open ifp = fopen( argv[1], "r" ); if (ifp == 0 ){ printf("Could not open file\n"); } else{ ofp = fopen(argv[2], "w"); dlist_init(list);//, (destroy)(hour, min, temp)); while (fscanf(ifp, "%d:%d %f ", &hour, &min, &temp) == 3) { current=list->tail; if(dlist_size(list)==0){ dlist_ins_prev(list, current, hour, min, temp); } else{ dlist_ins_next(list, current, hour, min, temp); } } current = list->head; while(current != NULL){ if(current==list->head){ current=current->next; } else if((current->temp > (current->prev->temp +5)) || (current->temp < (current->prev->temp -5))){ dlist_remove(list, current); current=current->next; } else current=current->next; } current = list->head; while(current != NULL){ printf("%d:%d %2.1lf\n" ,current->time, current->time2, current->temp ); fprintf(ofp, "%d:%d %2.1lf\n", current->time, current->time2, current->temp ); current = current->next; } //dlist_destroy(list); //} fclose(ifp); fclose(ofp); } } getchar(); } dlistdata.c #include <stdlib.h> #include <stdio.h> #include <string.h> #include "dlinklist.h" #include "DlistElmt.h" #include "dlistdata.h" /**************************************************************************************************/ void dlist_init(Dlist *list){ list->size = 0; list->head = NULL; list->tail = NULL; return; } void dlist_destroy(Dlist *list){ while (dlist_size(list) > 0){ dlist_remove(list, list->head); } memset(list, 0, sizeof(Dlist)); return; } int dlist_ins_next(Dlist *list, DlistElmt *element, const int time, const int time2, const float temp){ DlistElmt *new_element; if (element == NULL && dlist_size(list) != 0) return -1; if ((new_element = (DlistElmt *)malloc(sizeof(new_element))) == NULL) return -1; new_element->time = (int )time; new_element->time2 = (int )time2; new_element->temp = (float )temp; if (dlist_size(list) == 0) { list->head = new_element; list->head->prev = NULL; list->head->next = NULL; list->tail = new_element; } else { new_element->next = element->next; new_element->prev = element; if(element->next == NULL) list->tail = new_element; else element->next->prev = new_element; element->next = new_element; } list->size++; return 0; } int dlist_ins_prev(Dlist *list, DlistElmt *element, const int time, const int time2, const float temp){ DlistElmt *new_element; if (element == NULL && dlist_size(list) != 0) return -1; if ((new_element = (DlistElmt *)malloc(sizeof(new_element))) == NULL) return -1; new_element->time = (int )time; new_element->time2 = (int )time2; new_element->temp = (float )temp; if (dlist_size(list) == 0){ list->head = new_element; list->head->prev = NULL; list->head->next=NULL; list->tail = new_element; } else{ new_element->next = element; new_element->prev = element->prev; if(element->prev ==NULL) list->head = new_element; else element->prev->next = new_element; element->prev = new_element; } list->size++; return 0; } int dlist_remove(Dlist *list, DlistElmt *element){//, int time, int time2, float temp){ if (element == NULL || dlist_size(list) == 0) return -1; if (element == list->head) { list->head = element->next; if (list->head == NULL) list->tail = NULL; else element->next->prev = NULL; } else{ element->prev->next = element->next; if (element->next = NULL) list->tail = element->prev; else element->next->prev = element->prev; } free(element); list->size--; return 0; }

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  • Container item implementation

    - by onurozcelik
    Hi, I am working in Train Traffic Controller software project. My responsibility in this project is to develop the visual railroad GUI. We are implementing the project with Qt. By now I am using QGraphicsLinearLayout to hold my items. I am using the layout because I do not want to calculate coordinates of each item. So far I wrote item classes to add the layout. For instance SwitchItem class symbolizes railroad switch in real world. Each item class is responsible for its own painting and events. So far so good. Now I need a composite item that can contain two or more item. This class is going to be responsible for painting the items contained in it. I need this class because I have to put two or more items inside same layout cell. If I don' t put them in same cell I can' t use layout. See the image below. BlockSegmentItem and SignalItem inside same cell. Here is my compositeitem implementation. #include "compositeitem.h" CompositeItem::CompositeItem(QString id,QList<FieldItem *> _children) { children = _children; } CompositeItem::~CompositeItem() { } QRectF CompositeItem::boundingRect() const { FieldItem *child; QRectF rect(0,0,0,0); foreach(child,children) { rect = rect.united(child->boundingRect()); } return rect; } void CompositeItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget ) { FieldItem *child; foreach(child,children) { child->paint(painter,option,widget); } } QSizeF CompositeItem::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const { QSizeF itsSize(0,0); FieldItem *child; foreach(child,children) { // if its size empty set first child size to itsSize if(itsSize.isEmpty()) itsSize = child->sizeHint(Qt::PreferredSize); else { QSizeF childSize = child->sizeHint(Qt::PreferredSize); if(itsSize.width() < childSize.width()) itsSize.setWidth(childSize.width()); itsSize.setHeight(itsSize.height() + childSize.height()); } } return itsSize; } void CompositeItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event) { qDebug()<<"Test"; } This code works good with painting but when it comes to item events it is problematic. QGraphicsScene treats the composite item like a single item which is right for layout but not for events. Because each item has its own event implementation.(e.g. SignalItem has its special context menu event.) I have to handle item events seperately. Also I need a composite item implementation for the layout. How can I overcome this dilemma?

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  • Assignment operator that calls a constructor is broken

    - by Delan Azabani
    I've implemented some of the changes suggested in this question, and (thanks very much) it works quite well, however... in the process I've seemed to break the post-declaration assignment operator. With the following code: #include <cstdio> #include "ucpp" main() { ustring a = "test"; ustring b = "ing"; ustring c = "- -"; ustring d = "cafe\xcc\x81"; printf("%s\n", (a + b + c[1] + d).encode()); } I get a nice "testing cafe´" message. However, if I modify the code slightly so that the const char * conversion is done separately, post-declaration: #include <cstdio> #include "ucpp" main() { ustring a = "test"; ustring b = "ing"; ustring c = "- -"; ustring d; d = "cafe\xcc\x81"; printf("%s\n", (a + b + c[1] + d).encode()); } the ustring named d becomes blank, and all that is output is "testing ". My new code has three constructors, one void (which is probably the one being incorrectly used, and is used in the operator+ function), one that takes a const ustring &, and one that takes a const char *. The following is my new library code: #include <cstdlib> #include <cstring> class ustring { int * values; long len; public: long length() { return len; } ustring() { len = 0; values = (int *) malloc(0); } ustring(const ustring &input) { len = input.len; values = (int *) malloc(sizeof(int) * len); for (long i = 0; i < len; i++) values[i] = input.values[i]; } ustring operator=(ustring input) { ustring result(input); return result; } ustring(const char * input) { values = (int *) malloc(0); long s = 0; // s = number of parsed chars int a, b, c, d, contNeed = 0, cont = 0; for (long i = 0; input[i]; i++) if (input[i] < 0x80) { // ASCII, direct copy (00-7f) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = input[i]; } else if (input[i] < 0xc0) { // this is a continuation (80-bf) if (cont == contNeed) { // no need for continuation, use U+fffd values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } cont = cont + 1; values[s - 1] = values[s - 1] | ((input[i] & 0x3f) << ((contNeed - cont) * 6)); if (cont == contNeed) cont = contNeed = 0; } else if (input[i] < 0xc2) { // invalid byte, use U+fffd (c0-c1) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } else if (input[i] < 0xe0) { // start of 2-byte sequence (c2-df) contNeed = 1; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x1f) << 6; } else if (input[i] < 0xf0) { // start of 3-byte sequence (e0-ef) contNeed = 2; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x0f) << 12; } else if (input[i] < 0xf5) { // start of 4-byte sequence (f0-f4) contNeed = 3; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x07) << 18; } else { // restricted or invalid (f5-ff) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } len = s; } ustring operator=(const char * input) { ustring result(input); return result; } ustring operator+(ustring input) { ustring result; result.len = len + input.len; result.values = (int *) malloc(sizeof(int) * result.len); for (long i = 0; i < len; i++) result.values[i] = values[i]; for (long i = 0; i < input.len; i++) result.values[i + len] = input.values[i]; return result; } ustring operator[](long index) { ustring result; result.len = 1; result.values = (int *) malloc(sizeof(int)); result.values[0] = values[index]; return result; } char * encode() { char * r = (char *) malloc(0); long s = 0; for (long i = 0; i < len; i++) { if (values[i] < 0x80) r = (char *) realloc(r, s + 1), r[s + 0] = char(values[i]), s += 1; else if (values[i] < 0x800) r = (char *) realloc(r, s + 2), r[s + 0] = char(values[i] >> 6 | 0x60), r[s + 1] = char(values[i] & 0x3f | 0x80), s += 2; else if (values[i] < 0x10000) r = (char *) realloc(r, s + 3), r[s + 0] = char(values[i] >> 12 | 0xe0), r[s + 1] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 2] = char(values[i] & 0x3f | 0x80), s += 3; else r = (char *) realloc(r, s + 4), r[s + 0] = char(values[i] >> 18 | 0xf0), r[s + 1] = char(values[i] >> 12 & 0x3f | 0x80), r[s + 2] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 3] = char(values[i] & 0x3f | 0x80), s += 4; } return r; } };

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  • warning: returning reference to temporary

    - by Jack
    I have a function like this const string &SomeClass::Foo(int Value) { if (Value < 0 or Value > 10) return ""; else return SomeClass::StaticMember[i]; } I get warning: returning reference to temporary. Why is that? I thought the both values the function returns (reference to const char* "" and reference to a static member) cannot be temporary.

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