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  • How do interpreters functions written in the class C++ in the main

    - by T_Geek
    Hi I'm working on a project about Data structures. In the first , I wrote everything in main but it sounds like C . But as I learned, I tried to thinkk OOP and do as little as possible in my main() methods. I've implemented some opertation in my class like add,delet,find.it's too easy to implement its . class ARB { private: struct BT { int data; BT *l; BT *r; }; struct BT *p; public ARB(); ~ARB(); void del(int n); void add(int n); }; void ARB::del(int num) { //The code ,don't care about it }; main() { // BTR T; T.add(3); T.add(5); }; But I arrived to the big program How can I define a methode which have to use a binary tree and to get a stack STACK ARB::MyFunct(BT* p) { // The code don't care about it } How can I apply it in the main programme main() { // BT T; T.add(3); T.add(5); STACK S; BT* p S=T.MyFunct(p); // error C2664 cannot convert parametre 1 }; **mention :I implement STACK class

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  • Moving inserted container element if possible

    - by doublep
    I'm trying to achieve the following optimization in my container library: when inserting an lvalue-referenced element, copy it to internal storage; but when inserting rvalue-referenced element, move it if supported. The optimization is supposed to be useful e.g. if contained element type is something like std::vector, where moving if possible would give substantial speedup. However, so far I was unable to devise any working scheme for this. My container is quite complicated, so I can't just duplicate insert() code several times: it is large. I want to keep all "real" code in some inner helper, say do_insert() (may be templated) and various insert()-like functions would just call that with different arguments. My best bet code for this (a prototype, of course, without doing anything real): #include <iostream> #include <utility> struct element { element () { }; element (element&&) { std::cerr << "moving\n"; } }; struct container { void insert (const element& value) { do_insert (value); } void insert (element&& value) { do_insert (std::move (value)); } private: template <typename Arg> void do_insert (Arg arg) { element x (arg); } }; int main () { { // Shouldn't move. container c; element x; c.insert (x); } { // Should move. container c; c.insert (element ()); } } However, this doesn't work at least with GCC 4.4 and 4.5: it never prints "moving" on stderr. Or is what I want impossible to achieve and that's why emplace()-like functions exist in the first place?

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  • C++ interpreter conceptual problem

    - by Jan Wilkins
    I've built an interpreter in C++ for a language created by me. One main problem in the design was that I had two different types in the language: number and string. So I have to pass around a struct like: class myInterpreterValue { myInterpreterType type; int intValue; string strValue; } Objects of this class are passed around million times a second during e.g.: a countdown loop in my language. Profiling pointed out: 85% of the performance is eaten by the allocation function of the string template. This is pretty clear to me: My interpreter has bad design and doesn't use pointers enough. Yet, I don't have an option: I can't use pointers in most cases as I just have to make copies. How to do something against this? Is a class like this a better idea? vector<string> strTable; vector<int> intTable; class myInterpreterValue { myInterpreterType type; int locationInTable; } So the class only knows what type it represents and the position in the table This however again has disadvantages: I'd have to add temporary values to the string/int vector table and then remove them again, this would eat a lot of performance again. Help, how do interpreters of languages like Python or Ruby do that? They somehow need a struct that represents a value in the language like something that can either be int or string.

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  • How to use VC++ intrinsic functions w/o run-time library

    - by Adrian McCarthy
    I'm involved in one of those challenges where you try to produce the smallest possible binary, so I'm building my program without the C or C++ run-time libraries (RTL). I don't link to the DLL version or the static version. I don't even #include the header files. I have this working fine. For some code constructs, the compiler generates calls to memset(). For example: struct MyStruct { int foo; int bar; }; MyStruct blah = {}; // calls memset() Since I don't include the RTL, this results in a missing symbol at link time. I've been getting around this by avoiding those constructs. For the given example, I'll explicitly initialize the struct. MyStruct blah; blah.foo = 0; blah.bar = 0; But memset() can be useful, so I tried adding my own implementation. It works fine in Debug builds, even for those places where the compiler generates an implicit call to memset(). But in Release builds, I get an error saying that I cannot define an intrinsic function. You see, in Release builds, intrinsic functions are enabled, and memset() is an intrinsic. I would love to use the intrinsic for memset() in my release builds, since it's probably inlined and smaller and faster than my implementation. But I seem to be a in catch-22. If I don't define memset(), the linker complains that it's undefined. If I do define it, the compiler complains that I cannot define an intrinsic function. I've tried adding #pragma intrinsic(memset) with and without declarations of memset, but no luck. Does anyone know the right combination of definition, declaration, #pragma, and compiler and linker flags to get an intrinsic function without pulling in RTL overhead? Visual Studio 2008, x86, Windows XP+.

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  • LNK2001 error when compiling windows forms application with VC++ 2008

    - by Blin
    I've been trying to write a small application which will work with mysql in C++. I am using MySQL server 5.1.41 and MySQL C++ connector 1.0.5. Everything compiles fine when i write console applications, but when i try to compile windows forms application exactly the same way (same libraries, same paths, same project properties) i get this errors: Error 1 error LNK2001: unresolved external symbol "public: virtual int __clrcall sql::mysql::MySQL_Savepoint::getSavepointId(void)" (?getSavepointId@MySQL_Savepoint@mysql@sql@@$$FUAMHXZ) test1.obj test1 Error 2 error LNK2001: unresolved external symbol "public: virtual class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __clrcall sql::mysql::MySQL_Savepoint::getSavepointName(void)" (?getSavepointName@MySQL_Savepoint@mysql@sql@@$$FUAM?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ) test1.obj test1 following instructions from here, i've got this: Undecoration of :- "?getSavepointId@MySQL_Savepoint@mysql@sql@@UEAAHXZ" is :- "public: virtual int __cdecl sql::mysql::MySQL_Savepoint::getSavepointId(void) __ptr64" Undecoration of :- "?getSavepointName@MySQL_Savepoint@mysql@sql@@UEAA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ" is :- "public: virtual class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __cdecl sql::mysql::MySQL_Savepoint::getSavepointName(void) __ptr64" but what should i do now?

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  • Dynamic Method Creation

    - by TJMonk15
    So, I have been trying to research this all morning, and have had no luck. I am trying to find a way to dynamically create a method/delegate/lambda that returns a new instance of a certain class (not known until runtime) that inherits from a certain base class. I can guarantee the following about the unknown/dynamic class It will always inherit from one known Class (Row) It will have atleast 2 constructors (one accepting a long, and one accepting an IDataRecord) I plan on doign the following: Finding all classes that have a certain attribute on them Creating a delegate/method/lambda/whatever that creates a new instance of the class Storing the delegate/whatever along with some properties in a struct/class Insert the struct into a hashtable When needed, pull the info out of the hashtable and calling the delegate/whatever to get a new instance of the class and returning it/adding it to a list/etc. I need help only with #2 above!!! I have no idea where to start. I really just need some reference material to get me started, or some keywords to throw into google. This is for a compact/simple to use ORM for our office here. I understand the above is not simple, but once working, should make maintaining the code incredibly simple. Please let me know if you need any more info! And thanks in advance! :)

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  • How to initialize audio with Vala/SDL

    - by ioev
    I've been trying to figure this out for a few hours now. In order to start up the audio, I need to create an SDL.AudioSpec object and pass it to SDL.Audio.Open. The problem is, AudioSpec is a class with a private constructor, so when I try to create one I get: sdl.vala:18.25-18.43: error: `SDL.AudioSpec' does not have a default constructor AudioSpec audiospec = new SDL.AudioSpec(); ^^^^^^^^^^^^^^^^^^^ And if I try to just assign values to it's member vars like a struct (it's a struct in normal sdl) I get: sdl.vala:20.3-20.25: error: use of possibly unassigned local variable `audiospec' audiospec.freq = 22050; ^^^^^^^^^^^^^^^^^^^^^^^ I found the valac doc here: http://valadoc.org/sdl/SDL.AudioSpec.html But it isn't much help at all. The offending code block looks like this: // setup the audio configuration AudioSpec audiospec; AudioSpec specback; audiospec.freq = 22050; audiospec.format = SDL.AudioFormat.S16LSB; audiospec.channels = 2; audiospec.samples = 512; // try to initialize sound with these values if (SDL.Audio.open(audiospec, specback) < 0) { stdout.printf("ERROR! Check audio settings!\n"); return 1; } Any help would be greatly appreciated!

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  • Why do not C++11's move constructor/assignment operator act as expected

    - by xmllmx
    #include <iostream> using namespace std; struct A { A() { cout << "A()" << endl; } ~A() { cout << "~A()" << endl; } A(A&&) { cout << "A(A&&)" << endl; } A& operator =(A&&) { cout << "A& operator =(A&&)" << endl; return *this; } }; struct B { // According to the C++11, the move ctor/assignment operator // should be implicitly declared and defined. The move ctor // /assignment operator should implicitly call class A's move // ctor/assignment operator to move member a. A a; }; B f() { B b; // The compiler knows b is a temporary object, so implicitly // defined move ctor/assignment operator of class B should be // called here. Which will cause A's move ctor is called. return b; } int main() { f(); return 0; } My expected output should be: A() A(A&&) ~A() ~A() However, the actual output is: (The C++ compiler is: Visual Studio 2012) A() ~A() ~A() Is this a bug of VC++? or just my misunderstanding?

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  • How can I declare and initialize an array of pointers to a structure in C?

    - by worlds-apart89
    I have a small assignment in C. I am trying to create an array of pointers to a structure. My question is how can I initialize each pointer to NULL? Also, after I allocate memory for a member of the array, I can not assign values to the structure to which the array element points. #include <stdio.h> #include <stdlib.h> typedef struct list_node list_node_t; struct list_node { char *key; int value; list_node_t *next; }; int main() { list_node_t *ptr = (list_node_t*) malloc(sizeof(list_node_t)); ptr->key = "Hello There"; ptr->value = 1; ptr->next = NULL; // Above works fine // Below is erroneous list_node_t **array[10] = {NULL}; *array[0] = (list_node_t*) malloc(sizeof(list_node_t)); array[0]->key = "Hello world!"; //request for member ‘key’ in something not a structure or union array[0]->value = 22; //request for member ‘value’ in something not a structure or union array[0]->next = NULL; //request for member ‘next’ in something not a structure or union // Do something with the data at hand // Deallocate memory using function free return 0; }

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  • Deleting a node from linked list in C

    - by LuckySlevin
    My problem is deleting a node from linked list. I have two structs : typedef struct inner_list { int count; char word[100]; inner_list*next; } inner_list; typedef struct outer_list { char word [100]; inner_list * head; int count; outer_list * next; } outer_list; My problem is in deleting a node from outer_list linked list. For example when user entered aaa to delete, delete function should find the node with outer_list->word = aaa and delete this node and reconnect the list again. I tried the below code to do this. but After finding and deleting I'm losing the list. I don't know what's wrong. Please notice that outer_list have also a linked list of inner_list inside. void delnode(outer_list *head,char num[100]) { outer_list *temp, *m; temp=head; while(temp!=NULL) { if(strcmp(temp->word==num)==0) { if(temp==head) { head=temp->next; free(temp); return; } else { m->next=temp->next; free(temp); return; } }else { m=temp; temp= temp->next; } } printf(" ELEMENT %s NOT FOUND ", num); } What are your ideas about this?

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  • C# how to calculate hashcode from an object reference.

    - by Wayne
    Folks, here's a thorny problem for you! A part of the TickZoom system must collect instances of every type of object into a Dictionary< type. It is imperative that their equality and hash code be based on the instance of the object which means reference equality instead of value equality. The challenge is that some of the objects in the system have overridden Equals() and GetHashCode() for use as value equality and their internal values will change over time. That means that their Equals and GetHashCode are useless. How to solve this generically rather than intrusively? So far, We created a struct to wrap each object called ObjectHandle for hashing into the Dictionary. As you see below we implemented Equals() but the problem of how to calculate a hash code remains. public struct ObjectHandle : IEquatable<ObjectHandle>{ public object Object; public bool Equals(ObjectHandle other) { return object.ReferenceEquals(this.Object,other.Object); } } See? There is the method object.ReferenceEquals() which will compare reference equality without regard for any overridden Equals() implementation in the object. Now, how to calculate a matching GetHashCode() by only considering the reference without concern for any overridden GetHashCode() method? Ahh, I hope this give you an interesting puzzle. We're stuck over here. Sincerely, Wayne

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  • What is a NULL value

    - by Adi
    I am wondering , what exactly is stored in the memory when we say a particular variable pointer to be NULL. suppose I have a structure, say typdef struct MEM_LIST MEM_INSTANCE; struct MEM_LIST { char *start_addr; int size; MEM_INSTANCE *next; }; MEM_INSTANCE *front; front = (MEM_INSTANCE*)malloc(sizeof(MEM_INSTANCE*)); -1) If I make front=NULL. What will be the value which actually gets stored in the different fields of the front, say front-size ,front-start_addr. Is it 0 or something else. I have limited knowledge in this NULL thing. -2) If I do a free(front); It frees the memory which is pointed out by front. So what exactly free means here, does it make it NULL or make it all 0. -3) What can be a good strategy to deal with initialization of pointers and freeing them . Thanks in advance

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  • C++ explicit template specialization of templated constructor of templated class

    - by Victor Liu
    I have a class like template <class T> struct A{ template <class U> A(U u); }; I would like to write an explicit specialization of this for a declaration like A<int>::A(float); In the following test code, if I comment out the specialization, it compiles with g++. Otherwise, it says I have the wrong number of template parameters: #include <iostream> template <class T> struct A{ template <class U> A(T t, U *u){ *u += U(t); } }; template <> template <> A<int>::A<int,float>(int t, float *u){ *u += U(2*t); } int main(){ float f = 0; int i = 1; A<int>(i, &f); std::cout << f << std::endl; return 0; }

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  • Send C++ Structure to MSMQ Message

    - by Gobalakrishnan
    Hi, I am trying to send the below structure through MSMQ Message typedef struct { char cfiller[7]; short MsgCode; char cfiller1[11]; short MsgLength; char cfiller2[2]; } MESSAGECODE; typedef struct { MESSAGECODE Header; char DealerId[16]; char GroupId[16]; long Token; short Periodicity; double Deposit; double GrossExposureLimit; double NetExposureLimit; double NetSaleExposureLimit; double NetPositionLimit; double TurnoverLimit; double PendingOrdersLimit; double MTMLossLimit; double MaxSingleTransValue; long MaxSingleTransQty; double IMLimit; long NetQuantityLimit; } LIMITUPDATE; void main() { // // create queue // open queue // send message // OleInitialize(NULL); // have to init OLE // // declare some variables // IMSMQQueueInfoPtr qinfo("MSMQ.MSMQQueueInfo"); IMSMQQueuePtr qSend; IMSMQMessagePtr m("MSMQ.MSMQMessage"); LIMITUPDATE l1; l1.Header.MsgCode=26001; l1.Header.MsgLength=150; qinfo->PathName = ".\\private$\\q99"; m->Body = l1; qSend = qinfo->Open(MQ_SEND_ACCESS, MQ_DENY_NONE); m->Send(qSend); qSend->Close(); } while compiling i am getting the following error. Error 2 error C2664: 'IMSMQMessage::PutBody' : cannot convert parameter 1 from 'LIMITUPDATE' to 'const _variant_t &' c:\temp\msmq\msmq.cpp 58 msmq thank you.

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  • Interchange structured data between Haskell and C

    - by Eonil
    First, I'm a Haskell beginner. I'm planning integrating Haskell into C for realtime game. Haskell does logic, C does rendering. To do this, I have to pass huge complexly structured data (game state) from/to each other for each tick (at least 30 times per second). So the passing data should be lightweight. This state data may laid on sequential space on memory. Both of Haskell and C parts should access every area of the states freely. In best case, the cost of passing data can be copying a pointer to a memory. In worst case, copying whole data with conversion. I'm reading Haskell's FFI(http://www.haskell.org/haskellwiki/FFICookBook#Working_with_structs) The Haskell code look specifying memory layout explicitly. I have a few questions. Can Haskell specify memory layout explicitly? (to be matched exactly with C struct) Is this real memory layout? Or any kind of conversion required? (performance penalty) If Q#2 is true, Any performance penalty when the memory layout specified explicitly? What's the syntax #{alignment foo}? Where can I find the document about this? If I want to pass huge data with best performance, how should I do that? *PS Explicit memory layout feature which I said is just C#'s [StructLayout] attribute. Which is specifying in-memory position and size explicitly. http://www.developerfusion.com/article/84519/mastering-structs-in-c/ I'm not sure Haskell has matching linguistic construct matching with fields of C struct.

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  • Write to memory buffer instead of file with libjpeg?

    - by Richard Knop
    I have found this function which uses libjpeg to write to a file: int write_jpeg_file( char *filename ) { struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr; /* this is a pointer to one row of image data */ JSAMPROW row_pointer[1]; FILE *outfile = fopen( filename, "wb" ); if ( !outfile ) { printf("Error opening output jpeg file %s\n!", filename ); return -1; } cinfo.err = jpeg_std_error( &jerr ); jpeg_create_compress(&cinfo); jpeg_stdio_dest(&cinfo, outfile); /* Setting the parameters of the output file here */ cinfo.image_width = width; cinfo.image_height = height; cinfo.input_components = bytes_per_pixel; cinfo.in_color_space = color_space; /* default compression parameters, we shouldn't be worried about these */ jpeg_set_defaults( &cinfo ); /* Now do the compression .. */ jpeg_start_compress( &cinfo, TRUE ); /* like reading a file, this time write one row at a time */ while( cinfo.next_scanline < cinfo.image_height ) { row_pointer[0] = &raw_image[ cinfo.next_scanline * cinfo.image_width * cinfo.input_components]; jpeg_write_scanlines( &cinfo, row_pointer, 1 ); } /* similar to read file, clean up after we're done compressing */ jpeg_finish_compress( &cinfo ); jpeg_destroy_compress( &cinfo ); fclose( outfile ); /* success code is 1! */ return 1; } I would actually need to write the jpeg compressed image just to memory buffer, without saving it to a file, to save time. Could somebody give me an example how to do it? I have been searching the web for a while but the documentation is very rare if any and examples are also difficult to come by.

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  • Is it undefined behavior in the case of the private functions call in the initializer list?

    - by Alexey Malistov
    Consider the following code: struct Calc { Calc(const Arg1 & arg1, const Arg2 & arg2, /* */ const ArgN & argn) : arg1(arg1), arg2(arg2), /* */ argn(argn), coef1(get_coef1()), coef2(get_coef2()) { } int Calc1(); int Calc2(); int Calc3(); private: const Arg1 & arg1; const Arg2 & arg2; // ... const ArgN & argn; const int coef1; // I want to use const because const int coef2; // no modification is needed. int get_coef1() const { // calc coef1 using arg1, arg2, ..., argn; // undefined behavior? } int get_coef2() const { // calc coef2 using arg1, arg2, ..., argn and coef1; // undefined behavior? } }; struct Calc is not completely defined when I call get_coef1 and get_coef2 Is this code valid? Can I get UB?

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  • Are function-local typedefs visible inside C++0x lambdas?

    - by GMan - Save the Unicorns
    I've run into a strange problem. The following simplified code reproduces the problem in MSVC 2010 Beta 2: template <typename T> struct dummy { static T foo(void) { return T(); } }; int main(void) { typedef dummy<bool> dummy_type; auto x = [](void){ bool b = dummy_type::foo(); }; // auto x = [](void){ bool b = dummy<bool>::foo(); }; // works } The typedef I created locally in the function doesn't seem to be visible in the lambda. If I replace the typedef with the actual type, it works as expected. Here are some other test cases: // crashes the compiler, credit to Tarydon int main(void) { struct dummy {}; auto x = [](void){ dummy d; }; } // works as expected int main(void) { typedef int integer; auto x = [](void){ integer i = 0; }; } I don't have g++ 4.5 available to test it, right now. Is this some strange rule in C++0x, or just a bug in the compiler? From the results above, I'm leaning towards bug. Though the crash is definitely a bug. For now, I have filed two bug reports. All code snippets above should compile. The error has to do with using the scope resolution on locally defined scopes. (Spotted by dvide.) And the crash bug has to do with... who knows. :) Update According to the bug reports, they have both been fixed for the next release of Visual Studio 2010.

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  • Recursion in assembly?

    - by Davis
    I'm trying to get a better grasp of assembly, and I am a little confused about how to recursively call functions when I have to deal with registers, popping/pushing, etc. I am embedding x86 assembly in C++. Here I am trying to make a method which given an array of integers will build a linked list containing these integers in the order they appear in the array. I am doing this by calling a recursive function: insertElem (struct elem *head, struct elem *newElem, int data) -head: head of the list -data: the number that will be inserted at the end of a list -newElem: points to the location in memory where I will store the new element (data field) My problem is that I keep overwriting the registers instead of a typical linked list. For example, if I give it an array {2,3,1,8,3,9} my linked-list will return the first element (head) and only the last element, because the elements keep overwriting each other after head is no longer null. So here my linked list looks something like: 2--9 instead of 2--3--1--8--3--9 I feel like I don't have a grasp on how to organize and handle the registers. newElem is in EBX and just keeps getting rewritten. Thanks in advance!

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  • C callback functions defined in an unnamed namespace?

    - by Johannes Schaub - litb
    Hi all. I have a C++ project that uses a C bison parser. The C parser uses a struct of function pointers to call functions that create proper AST nodes when productions are reduced by bison: typedef void Node; struct Actions { Node *(*newIntLit)(int val); Node *(*newAsgnExpr)(Node *left, Node *right); /* ... */ }; Now, in the C++ part of the project, i fill those pointers class AstNode { /* ... */ }; class IntLit : public AstNode { /* ... */ }; extern "C" { Node *newIntLit(int val) { return (Node*)new IntLit(val); } /* ... */ } Actions createActions() { Actions a; a.newIntLit = &newIntLit; /* ... */ return a; } Now the only reason i put them within extern "C" is because i want them to have C calling conventions. But optimally, i would like their names still be mangled. They are never called by-name from C code, so name mangling isn't an issue. Having them mangled will avoid name conflicts, since some actions are called like error, and the C++ callback function has ugly names like the following just to avoid name clashes with other modules. extern "C" { void uglyNameError(char const *str) { /* ... */ } /* ... */ } a.error = &uglyNameError; I wondered whether it could be possible by merely giving the function type C linkage extern "C" void fty(char const *str); namespace { fty error; /* Declared! But i can i define it with that type!? */ } Any ideas? I'm looking for Standard-C++ solutions.

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  • Formulae for U and V buffer offset

    - by Abhi
    Hi all ! What should be the buffer offset value for U & V in YUV444 format type? Like for an example if i am using YV12 format the value is as follows: ppData.inputIDMAChannel.UBufOffset = iInputHeight * iInputWidth + (iInputHeight * iInputWidth)/4; ppData.inputIDMAChannel.VBufOffset = iInputHeight * iInputWidth; iInputHeight = 160 & iInputWidth = 112 ppdata is an object for the following structure: typedef struct ppConfigDataStruct { //--------------------------------------------------------------- // General controls //--------------------------------------------------------------- UINT8 IntType; // FIRSTMODULE_INTERRUPT: the interrupt will be // rised once the first sub-module finished its job. // FRAME_INTERRUPT: the interrput will be rised // after all sub-modules finished their jobs. //--------------------------------------------------------------- // Format controls //--------------------------------------------------------------- // For input idmaChannel inputIDMAChannel; BOOL bCombineEnable; idmaChannel inputcombIDMAChannel; UINT8 inputcombAlpha; UINT32 inputcombColorkey; icAlphaType alphaType; // For output idmaChannel outputIDMAChannel; CSCEQUATION CSCEquation; // Selects R2Y or Y2R CSC Equation icCSCCoeffs CSCCoeffs; // Selects R2Y or Y2R CSC Equation icFlipRot FlipRot; // Flip/Rotate controls for VF BOOL allowNopPP; // flag to indicate we need a NOP PP processing }*pPpConfigData, ppConfigData; and idmaChannel structure is as follows: typedef struct idmaChannelStruct { icFormat FrameFormat; // YUV or RGB icFrameSize FrameSize; // frame size UINT32 LineStride;// stride in bytes icPixelFormat PixelFormat;// Input frame RGB format, set NULL // to use standard settings. icDataWidth DataWidth;// Bits per pixel for RGB format UINT32 UBufOffset;// offset of U buffer from Y buffer start address // ignored if non-planar image format UINT32 VBufOffset;// offset of U buffer from Y buffer start address // ignored if non-planar image format } idmaChannel, *pIdmaChannel; I want the formulae for ppData.inputIDMAChannel.UBufOffset & ppData.inputIDMAChannel.VBufOffset for YUV444 Thanks in advance

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  • socket timeout and remove O_NONBLOCK option

    - by juxstapose
    Hello, I implemented a socket timeout and retry but in order to do it I had to set the socket as a non-blocking socket. However, I need the socket to block. This was my attempt at a solution to these two problems. This is not working. Subsequent send calls block but never send any data. When I connect without the select and the timeout, subsequent send calls work normally. References: C: socket connection timeout How to reset a socket back to blocking mode (after I set it to nonblocking mode)? Code: fd_set fdset; struct timeval tv; fcntl(dsock, F_SETFL, O_NONBLOCK); tv.tv_sec = theDeviceTimeout; tv.tv_usec = 0; int retries=0; logi(theLogOutput, LOG_INFO, "connecting to device socket num retrys: %i", theDeviceRetry); for(retries=0;retries<theDeviceRetry;retries++) { connect(dsock, (struct sockaddr *)&daddr, sizeof daddr); FD_ZERO(&fdset); FD_SET(dsock, &fdset); if (select(dsock + 1, NULL, &fdset, NULL, &tv) == 1) { int so_error; socklen_t slen = sizeof so_error; getsockopt(dsock, SOL_SOCKET, SO_ERROR, &so_error, &slen); if (so_error == 0) { logi(theLogOutput, LOG_INFO, "connected to socket on port %i on %s", theDevicePort, theDeviceIP); break; } else { logi(theLogOutput, LOG_WARN, "connect to %i failed on ip %s because %s retries %i", theDevicePort, theDeviceIP, strerror(errno), retries); logi(theLogOutput, LOG_WARN, "failed to connect to device %s", strerror(errno)); logi(theLogOutput, LOG_WARN, "error: %i %s", so_error, strerror(so_error)); continue; } } } int opts; opts = fcntl(dsock,F_GETFL); logi(theLogOutput, LOG_DEBUG, "clearing nonblock option %i retries %i", opts, retries); opts ^= O_NONBLOCK; fcntl(dsock, F_SETFL, opts);

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  • C++ Declarative Parsing Serialization

    - by Martin York
    Looking at Java and C# they manage to do some wicked processing based on special languaged based anotation (forgive me if that is the incorrect name). In C++ we have two problems with this: 1) There is no way to annotate a class with type information that is accessable at runtime. 2) Parsing the source to generate stuff is way to complex. But I was thinking that this could be done with some template meta-programming to achieve the same basic affect as anotations (still just thinking about it). Like char_traits that are specialised for the different types an xml_traits template could be used in a declaritive way. This traits class could be used to define how a class is serialised/deserialized by specializing the traits for the class you are trying to serialize. Example Thoughs: template<typename T> struct XML_traits { typedef XML_Empty Children; }; template<> struct XML_traits<Car> { typedef boost::mpl::vector<Body,Wheels,Engine> Children; }; template<typename T> std::ostream& Serialize(T const&) { // my template foo is not that strong. // but somthing like this. boost::mpl::for_each<typename XML_Traits<T>::Children,Serialize>(data); } template<> std::ostream& Serialize<XML_Empty>(T const&) { /* Do Nothing */ } My question is: Has anybody seen any projects/decumentation (not just XML) out there that uses techniques like this (template meta-programming) to emulate the concept of annotation used in languges like Java and C# that can then be used in code generation (to effectively automate the task by using a declaritive style). At this point in my research I am looking for more reading material and examples.

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  • C++ meta-splat function

    - by aaa
    hello. Is there an existing function (in boost mpl or fusion) to splat meta-vector to variadic template arguments? for example: splat<vector<T1, T2, ...>, function>::type same as function<T1, T2, ...> my search have not found one, and I do not want to reinvent one if it already exists. edit: after some tinkering, apparently it's next to impossible to accomplish this in general way, as it would require declaring full template template parameter list for all possible cases. only reasonable solution is to use macro: #define splat(name, function) \ template<class T, ...> struct name; \ template<class T> \ struct name<T,typename boost::enable_if_c< \ result_of::size<T>::value == 1>::type> { \ typedef function< \ typename result_of::value_at_c<T,0>::type \ > type; \ }; Oh well. thank you

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  • How can I modified the value of a string defined in a struc?

    - by Eric
    Hi, I have the following code in c++: define TAM 4000 define NUMPAGS 512 struct pagina { bitset<12 direccion; char operacion; char permiso; string *dato; int numero; }; void crearPagina(pagina* pag[], int pos, int dir) { pagina * paginas = (pagina*)malloc(sizeof(char) * TAM); paginas - direccion = bitset<12 (dir); paginas - operacion = 'n'; paginas - permiso = 'n'; string **tempDato = &paginas - dato; char *temp = " "; **tempDato = temp; paginas - numero = 0; pag[pos] = paginas; } I want to modify the value of the variable called "string *dato" in the struct pagina but, everytime I want to assing a new value, the compiler throws a segmentation fault. In this case I'm using a pointer to string, but I have also tried with a string. In a few words I want to do the following: pagina - dato = "test"; Any idea? Thanks in advance!!!

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