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  • How can I use Convert.ChangeType to convert string into numerics with group separator?

    - by Loic
    Hello, I want to make a generic string to numeric converter, and provide it as a string extension, so I wrote the following code: public static bool TryParse<T>( this string text, out T result, IFormatProvider formatProvider ) where T : struct try { result = (T)Convert.ChangeType( text, typeof( T ), formatProvider ); return true; } catch(... I call it like this: int value; var ok = "123".TryParse(out value, NumberFormatInfo.CurrentInfo) It works fine until I want to use a group separator: As I live in France, where the thousand separator is a space and the decimal separator is a comma, the string "1 234 567,89" should be equals to 1234567.89 (in Invariant culture). But, the function crashes! When a try to perform a non generic conversion, like double.Parse(...), I can use an overload which accepts a NumberStyles parameter. I specify NumberStyles.Number and this time it works! So, the questions are : Why the parsing does not respect my NumberFormatInfo (where the NumberGroupSeparator is well specified to a space, as I specified in my OS) How could I make work the generic version with Convert.ChangeTime, as it has no overload wich accepts a NumberStyles parameter ?

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  • BN_hex2bn magicaly segfaults in openSSL

    - by xunil154
    Greetings, this is my first post on stackoverflow, and i'm sorry if its a bit long. I'm trying to build a handshake protocol for my own project and am having issues with the server converting the clients RSA's public key to a Bignum. It works in my clent code, but the server segfaults when attempting to convert the hex value of the clients public RSA to a bignum. I have already checked that there is no garbidge before or after the RSA data, and have looked online, but i'm stuck. header segment: typedef struct KEYS { RSA *serv; char* serv_pub; int pub_size; RSA *clnt; } KEYS; KEYS keys; Initializing function: // Generates and validates the servers key /* code for generating server RSA left out, it's working */ //Set client exponent keys.clnt = 0; keys.clnt = RSA_new(); BN_dec2bn(&keys.clnt->e, RSA_E_S); // RSA_E_S contains the public exponent Problem code (in Network::server_handshake): // *Recieved an encrypted message from the network and decrypt into 'buffer' (1024 byte long)* cout << "Assigning clients RSA" << endl; // I have verified that 'buffer' contains the proper key if (BN_hex2bn(&keys.clnt->n, buffer) < 0) { Error("ERROR reading server RSA"); } cout << "clients RSA has been assigned" << endl; The program segfaults at BN_hex2bn(&keys.clnt->n, buffer) with the error (valgrind output) Invalid read of size 8 at 0x50DBF9F: BN_hex2bn (in /usr/lib/libcrypto.so.0.9.8) by 0x40F23E: Network::server_handshake() (Network.cpp:177) by 0x40EF42: Network::startNet() (Network.cpp:126) by 0x403C38: main (server.cpp:51) Address 0x20 is not stack'd, malloc'd or (recently) free'd Process terminating with default action of signal 11 (SIGSEGV) Access not within mapped region at address 0x20 at 0x50DBF9F: BN_hex2bn (in /usr/lib/libcrypto.so.0.9.8) And I don't know why it is, Im using the exact same code in the client program, and it works just fine. Any input is greatly appriciated!

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  • Linking errors when building against Boost Unit Test Framework

    - by Rafid
    I am trying to use Boost Unit Test Framework by building a stand alone library as detailed here: http://www.boost.org/doc/libs/1_35_0/libs/test/doc/components/utf/compilation.html So I created a VC library project containing the mentioned files and build it and it was successful. Then I created a test project and referenced the library project I just created, but when I tried to build it, I got the following linking errors: 1>Type.obj : error LNK2019: unresolved external symbol "bool __cdecl boost::test_tools::tt_detail::check_impl(class boost::test_tools::predicate_result const &,class boost::unit_test::lazy_ostream const &,class boost::unit_test::basic_cstring<char const >,unsigned __int64,enum boost::test_tools::tt_detail::tool_level,enum boost::test_tools::tt_detail::check_type,unsigned __int64,...)" (?check_impl@tt_detail@test_tools@boost@@YA_NAEBVpredicate_result@23@AEBVlazy_ostream@unit_test@3@V?$basic_cstring@$$CBD@63@_KW4tool_level@123@W4check_type@123@3ZZ) referenced in function "public: void __cdecl test1::test_method(void)" (?test_method@test1@@QEAAXXZ) 1>BoostUnitTestFramework.lib(framework.obj) : error LNK2019: unresolved external symbol "void __cdecl boost::debug::break_memory_alloc(long)" (?break_memory_alloc@debug@boost@@YAXJ@Z) referenced in function "void __cdecl boost::unit_test::framework::init(class boost::unit_test::test_suite * (__cdecl*)(int,char * * const),int,char * * const)" (?init@framework@unit_test@boost@@YAXP6APEAVtest_suite@23@HQEAPEAD@ZH0@Z) 1>BoostUnitTestFramework.lib(framework.obj) : error LNK2019: unresolved external symbol "void __cdecl boost::debug::detect_memory_leaks(bool)" (?detect_memory_leaks@debug@boost@@YAX_N@Z) referenced in function "void __cdecl boost::unit_test::framework::init(class boost::unit_test::test_suite * (__cdecl*)(int,char * * const),int,char * * const)" (?init@framework@unit_test@boost@@YAXP6APEAVtest_suite@23@HQEAPEAD@ZH0@Z) 1>BoostUnitTestFramework.lib(execution_monitor.obj) : error LNK2019: unresolved external symbol "bool __cdecl boost::debug::attach_debugger(bool)" (?attach_debugger@debug@boost@@YA_N_N@Z) referenced in function "public: int __cdecl boost::detail::system_signal_exception::operator()(unsigned int,struct _EXCEPTION_POINTERS *)" (??Rsystem_signal_exception@detail@boost@@QEAAHIPEAU_EXCEPTION_POINTERS@@@Z) 1>BoostUnitTestFramework.lib(execution_monitor.obj) : error LNK2019: unresolved external symbol "bool __cdecl boost::debug::under_debugger(void)" (?under_debugger@debug@boost@@YA_NXZ) referenced in function "public: int __cdecl boost::execution_monitor::execute(class boost::unit_test::callback0<int> const &)" (?execute@execution_monitor@boost@@QEAAHAEBV?$callback0@H@unit_test@2@@Z) 1>BoostUnitTestFramework.lib(unit_test_main.obj) : error LNK2019: unresolved external symbol "class boost::unit_test::test_suite * __cdecl init_unit_test_suite(int,char * * const)" (?init_unit_test_suite@@YAPEAVtest_suite@unit_test@boost@@HQEAPEAD@Z) referenced in function main 1>C:\Users\Rafid\Workspace\MyPhysics\Builds\VC10\Tests\Debug\Tests.exe : fatal error LNK1120: 6 unresolved externals They seem to be mainly caused by Boost debug library, but I can't see a reason why I should get linking errors putting in mind that Boost debug library only need to be included as header files, rather than linking against as a library! Any ideas?!

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  • Big and Little endian question

    - by Bobby
    I have the following code: // Incrementer datastores.cmtDatastores.u32Region[0] += 1; // Decrementer datastores.cmtDatastores.u32Region[1] = (datastores.cmtDatastores.u32Region[1] == 0) ? 10 : datastores.cmtDatastores.u32Region[1] - 1; // Toggler datastores.cmtDatastores.u32Region[2] = (datastores.cmtDatastores.u32Region[2] == 0x0000) ? 0xFFFF : 0x0000; The u32Region array is an unsigned int array that is part of a struct. Later in the code I convert this array to Big endian format: unsigned long *swapL = (unsigned long*)&datastores.cmtDatastores.u32Region[50]; for (int i=0;i<50;i++) { swapL[i] = _byteswap_ulong(swapL[i]); } This entire code snippet is part of a loop that repeats indefinitely. It is a contrived program that increments one element, decrements another and toggles a third element. The array is then sent via TCP to another machine that unpacks this data. The first loop works fine. After that, since the data is in big endian format, when I "increment", "decrement", and "toggle", the values are incorrect. Obviously, if in the first loop datastores.cmtDatastores.u32Region[0] += 1; results in 1, the second loop it should be 2, but it's not. It is adding the number 1(little endian) to the number in datastores.cmtDatastores.u32Region[0](big endian). I guess I have to revert back to little endian at the start of every loop, but it appears there should be an easier way to do this. Any thoughts? Thanks, Bobby

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  • Intellisense fails for boost::shared_ptr with Boost 1.40.0 in Visual Studio 2008

    - by Edward Loper
    I'm having trouble getting intellisense to auto-complete shared pointers for boost 1.40.0. (It works fine for Boost 1.33.1.) Here's a simple sample project file where auto-complete does not work: #include <boost/shared_ptr.hpp> struct foo { bool func() { return true; }; }; void bar() { boost::shared_ptr<foo> pfoo; pfoo.get(); // <-- intellisense does not autocomplete after "pfoo." pfoo->func(); // <-- intellisense does not autocomplete after "pfoo->" } When I right-click on shared_ptr, and do "Go to Definition," it brings be to a forward-declaration of the shared_ptr class in . It does not bring me to the actual definition, which is in However, it compiles fine, and auto-completion works fine for "boost::." Also, auto-completion works fine for boost::scoped_ptr and for boost::shared_array. Any ideas?

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  • Qt Object Linker Problem " undefined reverence to vtable"

    - by Thomas
    This is my header: #ifndef BARELYSOCKET_H #define BARELYSOCKET_H #include <QObject> //! The First Draw of the BarelySocket! class BarelySocket: public QObject { Q_OBJECT public: BarelySocket(); public slots: void sendMessage(Message aMessage); signals: void reciveMessage(Message aMessage); private: // QVector<Message> reciveMessages; }; #endif // BARELYSOCKET_H This is my class: #include <QTGui> #include <QObject> #include "type.h" #include "client.h" #include "server.h" #include "barelysocket.h" BarelySocket::BarelySocket() { //this->reciveMessages.clear(); qDebug("BarelySocket::BarelySocket()"); } void BarelySocket::sendMessage(Message aMessage) { } void BarelySocket::reciveMessage(Message aMessage) { } I get the Linker Problem : undefined reference to 'vtable for barelySocket' This should mean, i have a virtual Function not implemented. But as you can see, there is non. I comment the vector cause that should solve the Problem, but i does not. The Message is a complex struct, but even converting it to int did not solve it. I searched Mr G but he could not help me. Thank you for your support, Thomas

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  • Create ntp time stamp from gettimeofday

    - by krunk
    I need to calculate an ntp time stamp using gettimeofday. Below is how I've done it with comments on method. Look good to you guys? (minus error checking). Also, here's a codepad link. #include <unistd.h> #include <sys/time.h> const unsigned long EPOCH = 2208988800UL; // delta between epoch time and ntp time const double NTP_SCALE_FRAC = 4294967295.0; // maximum value of the ntp fractional part int main() { struct timeval tv; uint64_t ntp_time; uint64_t tv_ntp; double tv_usecs; gettimeofday(&tv, NULL); tv_ntp = tv.tv_sec + EPOCH; // convert tv_usec to a fraction of a second // next, we multiply this fraction times the NTP_SCALE_FRAC, which represents // the maximum value of the fraction until it rolls over to one. Thus, // .05 seconds is represented in NTP as (.05 * NTP_SCALE_FRAC) tv_usecs = (tv.tv_usec * 1e-6) * NTP_SCALE_FRAC; // next we take the tv_ntp seconds value and shift it 32 bits to the left. This puts the // seconds in the proper location for NTP time stamps. I recognize this method has an // overflow hazard if used after around the year 2106 // Next we do a bitwise AND with the tv_usecs cast as a uin32_t, dropping the fractional // part ntp_time = ((tv_ntp << 32) & (uint32_t)tv_usecs); }

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  • Trying to parse OpenCV YAML ouput with yaml-cpp

    - by Kenn Sebesta
    I've got a series of OpenCv generated YAML files and would like to parse them with yaml-cpp I'm doing okay on simple stuff, but the matrix representation is proving difficult. # Center of table tableCenter: !!opencv-matrix rows: 1 cols: 2 dt: f data: [ 240, 240] This should map into the vector 240 240 with type float. My code looks like: #include "yaml.h" #include <fstream> #include <string> struct Matrix { int x; }; void operator >> (const YAML::Node& node, Matrix& matrix) { unsigned rows; node["rows"] >> rows; } int main() { std::ifstream fin("monsters.yaml"); YAML::Parser parser(fin); YAML::Node doc; Matrix m; doc["tableCenter"] >> m; return 0; } But I get terminate called after throwing an instance of 'YAML::BadDereference' what(): yaml-cpp: error at line 0, column 0: bad dereference Abort trap I searched around for some documentation for yaml-cpp, but there doesn't seem to be any, aside from a short introductory example on parsing and emitting. Unfortunately, neither of these two help in this particular circumstance. As I understand, the !! indicate that this is a user-defined type, but I don't see with yaml-cpp how to parse that.

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  • Unmanaged DLL in C# Web Service

    - by Telis
    Hi Guys, please help µe as I am new into accessing an unmanaged DLL from C#.. I have a large unmanaged DLL in C++ and I am trying to access the DLL's classes and functions from a C# Web Service. I have seen many examples how to use DLLImport, but for some reason I am stuck with my very first wrapper method spending many hours with no luck.. What should I do to return an object in my 'Marshaled' [DllImport..] function? I would like to do something like that: [DllImport("unmanaged.dll")] public static extern MyClass MyFunction(); Here is the definition of my C++ class and the function that I want to access: class __declspec(dllexport) TPDate { public: TPDate(); TPDate(const TPDate& rhs); ... //today's date. static TPDate AsOfDate(void); ... } In my Web service I have declared the following StructLayout: [StructLayout(LayoutKind.Sequential)] public class TPDate { public TPDate(TPDate d) { _tpDate = d; } public TPDate _tpDate; } and here's where I think that I'm not doing something right: class WrapperTPDate { [DllImport("TPTools.dll", ExactSpelling=false, EntryPoint = "?AsOfDate@TPDate@@SA?AV1@XZ", CallingConvention = CallingConvention.StdCall)] [return: MarshalAs(UnmanagedType.Struct)] **public static extern TPDate AsOfDate();**// HERE THERE IS PROBLEM }; I am calling the wrapper as follows from my WebMethod: [WebMethod] public void ConstructModel() { TPDate date1 = WrapperTPDate.AsOfDate();// Here I get exception TPDate date = new TPDate(date1); } The exception i am getting is: System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.Runtime.InteropServices.MarshalDirectiveException: Cannot marshal 'return value': Invalid managed/unmanaged type combination (this type must be paired with LPStruct or Interface). If I change it to LPSTRUCT, I am getting another exception: System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt Could you please tell me where I'm doing wrong here Thanks

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  • css positioning

    - by bsreekanth
    Hello, I have uploaded a part of my screen below (link: http://yfrog.com/0d30127380p) It is part of a forum, so there are elements above and below it. The "Response Req.. Date" has a label, a date picker, and two drop down select control for time. I tried setting the width of the datepicker element, and a right margin so that the time selectors would position next to it. But it always sit below it. I'm not good in css positioning, so any suggestion would be highly appreciated. <div class="wrapper "> <label for="responseRequiredDate"> Response Required Date <span class="indicator">*</span> </label> <input type="hidden" name="responseRequiredDate" value="struct" /><div class="datetimepicker"> <div class="datePicker"> </div> <script> ...</script> <div class="timepicker"><select .... </div> </div> the date picker insert a script tag, would that cause a problem. probably not.

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  • Reinterpret a CGImageRef using PyObjC in Python

    - by Michael Rondinelli
    Hi, I'm doing something that's a little complicated to sum up in the title, so please bear with me. I'm writing a Python module that provides an interface to my C++ library, which provides some specialized image manipulation functionality. It would be most convenient to be able to access image buffers as CGImageRefs from Python, so they could be manipulated further using Quartz (using PyObjC, which works well). So I have a C++ function that provides a CGImageRef representation from my own image buffers, like this: CGImageRef CreateCGImageRefForImageBuffer(shared_ptr<ImageBuffer> buffer); I'm using Boost::Python to create my Python bridge. What is the easiest way for me to export this function so that I can use the CGImageRef from Python? Problems: The CGImageRef type can't be exported directly because it is a pointer to an undefined struct. So I could make a wrapper function that wraps it in a PyCObject or something to get it to send the pointer to Python. But then how do I "cast" this object to a CGImageRef from Python? Is there a better way to go about this?

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  • What is the best way to send structs containing enum values via sockets in C.

    - by Axel
    I've lots of different structs containing enum members that I have to transmit via TCP/IP. While the communication endpoints are on different operating systems (Windows XP and Linux) meaning different compilers (gcc 4.x.x and MSVC 2008) both program parts share the same header files with type declarations. For performance reasons, the structures should be transmitted directly (see code sample below) without expensively serializing or streaming the members inside. So the question is how to ensure that both compilers use the same internal memory representation for the enumeration members (i.e. both use 32-bit unsigned integers). Or if there is a better way to solve this problem... //type and enum declaration typedef enum { A = 1, B = 2, C = 3 } eParameter; typedef enum { READY = 400, RUNNING = 401, BLOCKED = 402 FINISHED = 403 } eState; #pragma pack(push,1) typedef struct { eParameter mParameter; eState mState; int32_t miSomeValue; uint8_t miAnotherValue; ... } tStateMessage; #pragma pack(pop) //... send via socket tStateMessage msg; send(iSocketFD,(void*)(&msg),sizeof(tStateMessage)); //... receive message on the other side tStateMessage msg_received; recv(iSocketFD,(void*)(&msg_received),sizeof(tStateMessage)); Additionally... Since both endpoints are little endian maschines, endianess is not a problem here. And the pack #pragma solves alignment issues satisfactorily. Thx for your answers, Axel

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  • AVL tree in C language

    - by I_S_W
    Hey all; i am currently doing a project that requires the use of AVL trees , the insert function i wrote for the avl does not seem to be working , it works for 3 or 4 nodes at maximum ; i would really appreciate your help The attempt is below enter code here Tree insert(Tree t,char name[80],int num) { if(t==NULL) { t=(Tree)malloc(sizeof(struct node)); if(t!=NULL) { strcpy(t->name,name); t->num=num; t->left=NULL; t->right=NULL; t->height=0; } } else if(strcmp(name,t->name)<0) { t->left=insert(t->left,name,num); if((height(t->left)-height(t->right))==2) if(strcmp(name,t->left->name)<0) { t=s_rotate_left(t);} else{ t=d_rotate_left(t);} } else if(strcmp(name,t-name)0) { t-right=insert(t-right,name,num); if((height(t-right)-height(t-left))==2) if(strcmp(name,t-right-name)0){ t=s_rotate_right(t); } else{ t=d_rotate_right(t);} } t-height=max(height(t-left),height(t-right))+1; return t; }

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  • Python: combining making two scripts into one

    - by Alex
    I have two separately made python scripts one that makes a sine wave sound based off time, and another that produces a sine wave graph that is based off the same time factors. I need help combining them into one running file. Here's the first: from struct import pack from math import sin, pi import time def au_file(name, freq, freq1, dur, vol): fout = open(name, 'wb') # header needs size, encoding=2, sampling_rate=8000, channel=1 fout.write('.snd' + pack('>5L', 24, 8*dur, 2, 8000, 1)) factor = 2 * pi * freq/8000 factor1 = 2 * pi * freq1/8000 # write data for seg in range(8 * dur): # sine wave calculations sin_seg = sin(seg * factor) + sin(seg * factor1) fout.write(pack('b', vol * 64 * sin_seg)) fout.close() t = time.strftime("%S", time.localtime()) ti = time.strftime("%M", time.localtime()) tis = float(t) tis = tis * 100 tim = float(ti) tim = tim * 100 if __name__ == '__main__': au_file(name='timeSound.au', freq=tim, freq1=tis, dur=1000, vol=1.0) import os os.startfile('timeSound.au') and the second is this: from Tkinter import * import math import time t = time.strftime("%S", time.localtime()) ti = time.strftime("%M", time.localtime()) tis = float(t) tis = tis / 100 tim = float(ti) tim = tim / 100 root = Tk() root.title("This very moment") width = 400 height = 300 center = height//2 x_increment = 1 # width stretch x_factor1 = tis x_factor2 = tim # height stretch y_amplitude = 50 c = Canvas(width=width, height=height, bg='black') c.pack() str1 = "sin(x)=white" c.create_text(10, 20, anchor=SW, text=str1) center_line = c.create_line(0, center, width, center, fill='red') # create the coordinate list for the sin() curve, have to be integers xy1 = [] xy2 = [] for x in range(400): # x coordinates xy1.append(x * x_increment) xy2.append(x * x_increment) # y coordinates xy1.append(int(math.sin(x * x_factor1) * y_amplitude) + center) xy2.append(int(math.sin(x * x_factor2) * y_amplitude) + center) sinS_line = c.create_line(xy1, fill='white') sinM_line = c.create_line(xy2, fill='yellow') root.mainloop()

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  • OpenNETCF.Stopwatch -> only ticks changing, not Elapsed

    - by pithyless
    I've been trying to track down a bug I thought was thread-related, but I think instead there is an issue with the way I am using OpenNETCF's Stopwatch. I am using OpenNETCF.IoC in my application, but for the sake of simplicity I moved the following code directly into a view: public partial class WorkoutView : SmartPart { ... private Stopwatch stopwatch; public WorkoutView() { ... stopwatch = new Stopwatch(); stopwatch.Reset(); stopwatch.Start(); WorkoutDisplayTimer = new Timer(); WorkoutDisplayTimer.Interval = 500; WorkoutDisplayTimer.Tick += new EventHandler(WorkoutDisplayTimer_Tick); WorkoutDisplayTimer.Enabled = true; } void WorkoutDisplayTimer_Tick(object sender, EventArgs e) { ... stopwatch.Stop(); lbl.Text = stopwatch.ElapsedTicks.ToString() + "NOT WORKING: " + stopwatch.Elapsed.ToString(); stopwatch.Start(); } ... } Long story short, looking at stopwatch in the debugger, the only values that ever get updated are ElapsedTicks, mElapsed, mStartPerfCount. Everything else is always zero. Is this expected behavior? Do I need to call an additional method to have the stopwatch calculate the Elapsed struct? (Note: stopwatch.ElapsedMilliseconds is also zero)

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  • XML Serialize and Deserialize Problem XML Structure

    - by Ph.E
    Camarades, I'm having the following problem. Caught a list Struct, Serialize (Valid W3C) and send to a WebService. In the WebService I receive, transform to a string, valid by the W3C and then Deserializer, but when I try to run it, always occurs error, saying that some objects were not closed. Any help? Sent Code: #region ListToXML private XmlDocument ListToXMLDocument(object __Lista) { XmlDocument _ListToXMLDocument = new XmlDocument(); try { XmlDocument _XMLDoc = new XmlDocument(); MemoryStream _StreamMem = new MemoryStream(); XmlSerializer _XMLSerial = new XmlSerializer(__Lista.GetType()); StreamWriter _StreamWriter = new StreamWriter(_StreamMem, Encoding.UTF8); _XMLSerial.Serialize(_StreamWriter, __Lista); _StreamMem.Position = 0; _XMLDoc.Load(_StreamMem); if (_XMLDoc.ChildNodes.Count > 0) _ListToXMLDocument = _XMLDoc; } catch (Exception __Excp) { new uException(__Excp).GerarLogErro(CtNomeBiblioteca); } return _ListToXMLDocument; } #endregion Receive Code: #region XMLDocumentToTypedList private List<T> XMLDocumentToTypedList<T>(string __XMLDocument) { List<T> _XMLDocumentToTypedList = new List<T>(); try { XmlSerializer _XMLSerial = new XmlSerializer(typeof(List<T>)); MemoryStream _MemStream = new MemoryStream(); StreamWriter _StreamWriter = new StreamWriter(_MemStream, Encoding.UTF8); _StreamWriter.Write(__XMLDocument); _MemStream.Position = 0; _XMLDocumentToTypedList = (List<T>)_XMLSerial.Deserialize(_MemStream); return _XMLDocumentToTypedList; } catch (Exception _Ex) { new uException(_Ex).GerarLogErro(CtNomeBiblioteca); throw _Ex; } } #endregion

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  • What sorting algorithm is this?

    - by Mike
    Hi, I have a sorting algorithm as follows. My question is, which sorting algorithm is this? I thought it was bubble sort, but it does not do multiple runs. Any idea? Thanks! //sorting in descending order struct node { int value; node* NEXT; } //Assume HEAD pointer denotes the first element in the //linked list // only change the values…don’t have to change the //pointers Sort( Node *Head) { node* first,second,temp; first= Head; while(first!=null) { second=first->NEXT; while(second!=null) { if(first->value < second->value) { temp = new node(); temp->value=first->value; first->value=second->value; second->value=temp->value; delete temp; } second=second->NEXT; } first=first->NEXT; } }

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  • Removing padding from structure in kernel module

    - by dexkid
    I am compiling a kernel module, containing a structure of size 34, using the standard command. make -C /lib/modules/$(KVERSION)/build M=$(PWD) modules The sizeof(some_structure) is coming as 36 instead of 34 i.e. the compiler is padding the structure. How do I remove this padding? Running make V=1 shows the gcc compiler options passed as make -I../inc -C /lib/modules/2.6.29.4-167.fc11.i686.PAE/build M=/home/vishal/20100426_eth_vishal/organised_eth/src modules make[1]: Entering directory `/usr/src/kernels/2.6.29.4-167.fc11.i686.PAE' test -e include/linux/autoconf.h -a -e include/config/auto.conf || ( \ echo; \ echo " ERROR: Kernel configuration is invalid."; \ echo " include/linux/autoconf.h or include/config/auto.conf are missing."; \ echo " Run 'make oldconfig && make prepare' on kernel src to fix it."; \ echo; \ /bin/false) mkdir -p /home/vishal/20100426_eth_vishal/organised_eth/src/.tmp_versions ; rm -f /home/vishal/20100426_eth_vishal/organised_eth/src/.tmp_versions/* make -f scripts/Makefile.build obj=/home/vishal/20100426_eth_vishal/organised_eth/src gcc -Wp,-MD,/home/vishal/20100426_eth_vishal/organised_eth/src/.eth_main.o.d -nostdinc -isystem /usr/lib/gcc/i586-redhat-linux/4.4.0/include -Iinclude -I/usr/src/kernels/2.6.29.4-167.fc11.i686.PAE/arch/x86/include -include include/linux/autoconf.h -D__KERNEL__ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -Werror-implicit-function-declaration -Os -m32 -msoft-float -mregparm=3 -freg-struct-return -mpreferred-stack-boundary=2 -march=i686 -mtune=generic -Wa,-mtune=generic32 -ffreestanding -DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1 -pipe -Wno-sign-compare -fno-asynchronous-unwind-tables -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -Iarch/x86/include/asm/mach-generic -Iarch/x86/include/asm/mach-default -Wframe-larger-than=1024 -fno-stack-protector -fno-omit-frame-pointer -fno-optimize-sibling-calls -g -pg -Wdeclaration-after-statement -Wno-pointer-sign -fwrapv -fno-dwarf2-cfi-asm -DTX_DESCRIPTOR_IN_SYSTEM_MEMORY -DRX_DESCRIPTOR_IN_SYSTEM_MEMORY -DTX_BUFFER_IN_SYSTEM_MEMORY -DRX_BUFFER_IN_SYSTEM_MEMORY -DALTERNATE_DESCRIPTORS -DEXT_8_BYTE_DESCRIPTOR -O0 -Wall -DT_ETH_1588_051 -DALTERNATE_DESCRIPTORS -DEXT_8_BYTE_DESCRIPTOR -DNETHERNET_INTERRUPTS -DETH_IEEE1588_TESTS -DSNAPTYPSEL_TMSTRENA_TEVENTENA_TESTS -DT_ETH_1588_140_147 -DLOW_DEBUG_PRINTS -DMEDIUM_DEBUG_PRINTS -DHIGH_DEBUG_PRINTS -DMODULE -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(eth_main)" -D"KBUILD_MODNAME=KBUILD_STR(conxt_eth)" -c -o /home/vishal/20100426_eth_vishal/organised_eth/src/eth_main.o /home/vishal/20100426_eth_vishal/organised_eth/src/eth_main.c

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  • Execution time in nano seconds and related issues

    - by anup
    Hi All, I am using the following code to compute execution time in milli-secs. struct timespec tp; if (clock_gettime (CLOCK_REALTIME, &tp) == 0) return ((tp.tv_sec * 1000000000) + tp.tv_nsec); else return ; Can you please tell me whether this is correct? Let's name this function comptime_nano(). Now, I write the following code in main() to check execution times of following operations. unsigned long int a, b, s1, s3; a = (unsigned long int)(1) << 63; b = (unsigned long int)(1) << 63; btime = comptime_nano(); s1 = b >> 30; atime = comptime_nano(); printf ("Time =%ld for %lu\n", (atime - btime), s1); btime = comptime_nano(); s3 = a >> 1; atime = comptime_nano(); printf ("Time =%ld for %lu\n", (atime - btime), s3); To my surprise, the first operation takes about roughly 4 times more time than the second. Again, if I change the relative ordering of these operations, the respective timings change drastically. Please comment...

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  • Query on simple C++ threadpool implementation

    - by ticketman
    Stackoverflow has been a tremendous help to me and I'd to give something back to the community. I have been implementing a simple threadpool using the tinythread C++ portable thread library, using what I have learnt from Stackoverflow. I am new to thread programming, so not that comfortable with mutexes, etc. I have a question best asked after presenting the code (which runs quite well under Linux): // ThreadPool.h class ThreadPool { public: ThreadPool(); ~ThreadPool(); // Creates a pool of threads and gets them ready to be used void CreateThreads(int numOfThreads); // Assigns a job to a thread in the pool, but doesn't start the job // Each SubmitJob call will use up one thread of the pool. // This operation can only be undone by calling StartJobs and // then waiting for the jobs to complete. On completion, // new jobs may be submitted. void SubmitJob( void (*workFunc)(void *), void *workData ); // Begins execution of all the jobs in the pool. void StartJobs(); // Waits until all jobs have completed. // The wait will block the caller. // On completion, new jobs may be submitted. void WaitForJobsToComplete(); private: enum typeOfWorkEnum { e_work, e_quit }; class ThreadData { public: bool ready; // thread has been created and is ready for work bool haveWorkToDo; typeOfWorkEnum typeOfWork; // Pointer to the work function each thread has to call. void (*workFunc)(void *); // Pointer to work data void *workData; ThreadData() : ready(false), haveWorkToDo(false) { }; }; struct ThreadArgStruct { ThreadPool *threadPoolInstance; int threadId; }; // Data for each thread ThreadData *m_ThreadData; ThreadPool(ThreadPool const&); // copy ctor hidden ThreadPool& operator=(ThreadPool const&); // assign op. hidden // Static function that provides the function pointer that a thread can call // By including the ThreadPool instance in the void * parameter, // we can use it to access other data and methods in the ThreadPool instance. static void ThreadFuncWrapper(void *arg) { ThreadArgStruct *threadArg = static_cast<ThreadArgStruct *>(arg); threadArg->threadPoolInstance->ThreadFunc(threadArg->threadId); } // The function each thread calls void ThreadFunc( int threadId ); // Called by the thread pool destructor void DestroyThreadPool(); // Total number of threads available // (fixed on creation of thread pool) int m_numOfThreads; int m_NumOfThreadsDoingWork; int m_NumOfThreadsGivenJobs; // List of threads std::vector<tthread::thread *> m_ThreadList; // Condition variable to signal each thread has been created and executing tthread::mutex m_ThreadReady_mutex; tthread::condition_variable m_ThreadReady_condvar; // Condition variable to signal each thread to start work tthread::mutex m_WorkToDo_mutex; tthread::condition_variable m_WorkToDo_condvar; // Condition variable to signal the main thread that // all threads in the pool have completed their work tthread::mutex m_WorkCompleted_mutex; tthread::condition_variable m_WorkCompleted_condvar; }; cpp file: // // ThreadPool.cpp // #include "ThreadPool.h" // This is the thread function for each thread. // All threads remain in this function until // they are asked to quit, which only happens // when terminating the thread pool. void ThreadPool::ThreadFunc( int threadId ) { ThreadData *myThreadData = &m_ThreadData[threadId]; std::cout << "Hello world: Thread " << threadId << std::endl; // Signal that this thread is ready m_ThreadReady_mutex.lock(); myThreadData->ready = true; m_ThreadReady_condvar.notify_one(); // notify the main thread m_ThreadReady_mutex.unlock(); while(true) { //tthread::lock_guard<tthread::mutex> guard(m); m_WorkToDo_mutex.lock(); while(!myThreadData->haveWorkToDo) // check for work to do m_WorkToDo_condvar.wait(m_WorkToDo_mutex); // if no work, wait here myThreadData->haveWorkToDo = false; // need to do this before unlocking the mutex m_WorkToDo_mutex.unlock(); // Do the work switch(myThreadData->typeOfWork) { case e_work: std::cout << "Thread " << threadId << ": Woken with work to do\n"; // Do work myThreadData->workFunc(myThreadData->workData); std::cout << "#Thread " << threadId << ": Work is completed\n"; break; case e_quit: std::cout << "Thread " << threadId << ": Asked to quit\n"; return; // ends the thread } // Now to signal the main thread that my work is completed m_WorkCompleted_mutex.lock(); m_NumOfThreadsDoingWork--; // Unsure if this 'if' would make the program more efficient // if(NumOfThreadsDoingWork == 0) m_WorkCompleted_condvar.notify_one(); // notify the main thread m_WorkCompleted_mutex.unlock(); } } ThreadPool::ThreadPool() { m_numOfThreads = 0; m_NumOfThreadsDoingWork = 0; m_NumOfThreadsGivenJobs = 0; } ThreadPool::~ThreadPool() { if(m_numOfThreads) { DestroyThreadPool(); delete [] m_ThreadData; } } void ThreadPool::CreateThreads(int numOfThreads) { // Check a thread pool has already been created if(m_numOfThreads > 0) return; m_NumOfThreadsGivenJobs = 0; m_NumOfThreadsDoingWork = 0; m_numOfThreads = numOfThreads; m_ThreadData = new ThreadData[m_numOfThreads]; ThreadArgStruct threadArg; for(int i=0; i<m_numOfThreads; ++i) { threadArg.threadId = i; threadArg.threadPoolInstance = this; // Creates the thread and save in a list so we can destroy it later m_ThreadList.push_back( new tthread::thread( ThreadFuncWrapper, (void *)&threadArg ) ); // It takes a little time for a thread to get established. // Best wait until it gets established before creating the next thread. m_ThreadReady_mutex.lock(); while(!m_ThreadData[i].ready) // Check if thread is ready m_ThreadReady_condvar.wait(m_ThreadReady_mutex); // If not, wait here m_ThreadReady_mutex.unlock(); } } // Adds a job to the batch, but doesn't start the job void ThreadPool::SubmitJob(void (*workFunc)(void *), void *workData) { // Check that the thread pool has been created if(!m_numOfThreads) return; if(m_NumOfThreadsGivenJobs >= m_numOfThreads) return; m_ThreadData[m_NumOfThreadsGivenJobs].workFunc = workFunc; m_ThreadData[m_NumOfThreadsGivenJobs].workData = workData; std::cout << "Submitted job " << m_NumOfThreadsGivenJobs << std::endl; m_NumOfThreadsGivenJobs++; } void ThreadPool::StartJobs() { // Check that the thread pool has been created // and some jobs have been assigned if(!m_numOfThreads || !m_NumOfThreadsGivenJobs) return; // Set 'haveworkToDo' flag for all threads m_WorkToDo_mutex.lock(); for(int i=0; i<m_NumOfThreadsGivenJobs; ++i) m_ThreadData[i].haveWorkToDo = true; m_NumOfThreadsDoingWork = m_NumOfThreadsGivenJobs; // Reset this counter so we can resubmit jobs later m_NumOfThreadsGivenJobs = 0; // Notify all threads they have work to do m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); } void ThreadPool::WaitForJobsToComplete() { // Check that a thread pool has been created if(!m_numOfThreads) return; m_WorkCompleted_mutex.lock(); while(m_NumOfThreadsDoingWork > 0) // Check if all threads have completed their work m_WorkCompleted_condvar.wait(m_WorkCompleted_mutex); // If not, wait here m_WorkCompleted_mutex.unlock(); } void ThreadPool::DestroyThreadPool() { std::cout << "Ask threads to quit\n"; m_WorkToDo_mutex.lock(); for(int i=0; i<m_numOfThreads; ++i) { m_ThreadData[i].haveWorkToDo = true; m_ThreadData[i].typeOfWork = e_quit; } m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); // As each thread terminates, catch them here for(int i=0; i<m_numOfThreads; ++i) { tthread::thread *t = m_ThreadList[i]; // Wait for thread to complete t->join(); } m_numOfThreads = 0; } Example of usage: (this calculates pi-squared/6) struct CalculationDataStruct { int inputVal; double outputVal; }; void LongCalculation( void *theSums ) { CalculationDataStruct *sums = (CalculationDataStruct *)theSums; int terms = sums->inputVal; double sum; for(int i=1; i<terms; i++) sum += 1.0/( double(i)*double(i) ); sums->outputVal = sum; } int main(int argc, char** argv) { int numThreads = 10; // Create pool ThreadPool threadPool; threadPool.CreateThreads(numThreads); // Create thread workspace CalculationDataStruct sums[numThreads]; // Set up jobs for(int i=0; i<numThreads; i++) { sums[i].inputVal = 3000*(i+1); threadPool.SubmitJob(LongCalculation, &sums[i]); } // Run the jobs threadPool.StartJobs(); threadPool.WaitForJobsToComplete(); // Print results for(int i=0; i<numThreads; i++) std::cout << "Sum of " << sums[i].inputVal << " terms is " << sums[i].outputVal << std::endl; return 0; } Question: In the ThreadPool::ThreadFunc method, would better performance be obtained if the following if statement if(NumOfThreadsDoingWork == 0) was included? Also, I'd be grateful of criticisms and ways to improve the code. At the same time, I hope the code is of use to others.

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  • Variant datatype library for C

    - by Joey Adams
    Is there a decent open-source C library for storing and manipulating dynamically-typed variables (a.k.a. variants)? I'm primarily interested in atomic values (int8, int16, int32, uint, strings, blobs, etc.), while JSON-style arrays and objects as well as custom objects would also be nice. A major case where such a library would be useful is in working with SQL databases. The most obvious feature of such a library would be a single type for all supported values, e.g.: struct Variant { enum Type type; union { int8_t int8_; int16_t int16_; // ... }; }; Other features might include converting Variant objects to/from C structures (using a binding table), converting values to/from strings, and integration with an existing database library such as SQLite. Note: I do not believe this is question is a duplicate of http://stackoverflow.com/questions/649649/any-library-for-generic-datatypes-in-c , which refers to "queues, trees, maps, lists". What I'm talking about focuses more on making working with SQL databases roughly as smooth as working with them in interpreted languages.

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  • Call dll - pcshll32.dll using delphi

    - by Davis
    Hi, I need to call hllapi function of pcshll32.dll using delphi. It's works with personal communications of ibm. How can i change the code bellow to delphi ? Thanks !!! The EHLLAPI entry point (hllapi) is always called with the following four parameters: EHLLAPI Function Number (input) Data Buffer (input/output) Buffer Length (input/output) Presentation Space Position (input); Return Code (output) The prototype for IBM Standard EHLLAPI is: [long hllapi (LPWORD, LPSTR, LPWORD, LPWORD); The prototype for IBM Enhanced EHLLAPI is: [long hllapi (LPINT, LPSTR, LPINT, LPINT); Each parameter is passed by reference not by value. Thus each parameter to the function call must be a pointer to the value, not the value itself. For example, the following is a correct example of calling the EHLLAPI Query Session Status function: #include "hapi_c.h" struct HLDQuerySessionStatus QueryData; int Func, Len, Rc; long Rc; memset(QueryData, 0, sizeof(QueryData)); // Init buffer QueryData.qsst_shortname = ©A©; // Session to query Func = HA_QUERY_SESSION_STATUS; // Function number Len = sizeof(QueryData); // Len of buffer Rc = 0; // Unused on input hllapi(&Func, (char *)&QueryData, &Len, &Rc); // Call EHLLAPI if (Rc != 0) { // Check return code // ...Error handling } All the parameters in the hllapi call are pointers and the return code of the EHLLAPI function is returned in the value of the 4th parameter, not as the value of the function.

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  • Multiplication algorithm for abritrary precision (bignum) integers.

    - by nn
    Hi, I'm writing a small bignum library for a homework project. I am to implement Karatsuba multiplication, but before that I would like to write a naive multiplication routine. I'm following a guide written by Paul Zimmerman titled "Modern Computer Arithmetic" which is freely available online. On page 4, there is a description of an algorithm titled BasecaseMultiply which performs gradeschool multiplication. I understand step 2, 3, where B^j is a digit shift of 1, j times. But I don't understand step 1 and 3, where we have A*b_j. How is this multiplication meant to be carried out if the bignum multiplication hasn't been defined yet? Would the operation "*" in this algorithm just be the repeated addition method? Here is the parts I have written thus far. I have unit tested them so they appear to be correct for the most part: The structure I use for my bignum is as follows: #define BIGNUM_DIGITS 2048 typedef uint32_t u_hw; // halfword typedef uint64_t u_w; // word typedef struct { unsigned int sign; // 0 or 1 unsigned int n_digits; u_hw digits[BIGNUM_DIGITS]; } bn; Currently available routines: bn *bn_add(bn *a, bn *b); // returns a+b as a newly allocated bn void bn_lshift(bn *b, int d); // shifts d digits to the left, retains sign int bn_cmp(bn *a, bn *b); // returns 1 if a>b, 0 if a=b, -1 if a<b

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  • valgrind complains doing a very simple strtok in c

    - by monkeyking
    Hi I'm trying to tokenize a string by loading an entire file into a char[] using fread. For some strange reason it is not always working, and valgrind complains in this very small sample program. Given an input like test.txt first second And the following program #include <stdio.h> #include <string.h> #include <stdlib.h> #include <sys/stat.h> //returns the filesize in bytes size_t fsize(const char* fname){ struct stat st ; stat(fname,&st); return st.st_size; } int main(int argc, char *argv[]){ FILE *fp = NULL; if(NULL==(fp=fopen(argv[1],"r"))){ fprintf(stderr,"\t-> Error reading file:%s\n",argv[1]); return 0; } char buffer[fsize(argv[1])]; fread(buffer,sizeof(char),fsize(argv[1]),fp); char *str = strtok(buffer," \t\n"); while(NULL!=str){ fprintf(stderr,"token is:%s with strlen:%lu\n",str,strlen(str)); str = strtok(NULL," \t\n"); } return 0; } compiling like gcc test.c -std=c99 -ggdb running like ./a.out test.txt thanks

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  • is delete p where p is a pointer to array a memory leak ?

    - by Eli
    following a discussion in a software meeting I setup to find out if deleting an dynamically allocated primitive array with plain delete will cause a memory leak. I have written this tiny program and compiled with visual studio 2008 running on windows XP: #include "stdafx.h" #include "Windows.h" const unsigned long BLOCK_SIZE = 1024*100000; int _tmain() { for (unsigned int i =0; i < 1024*1000; i++) { int* p = new int[1024*100000]; for (int j =0;j<BLOCK_SIZE;j++) p[j]= j % 2; Sleep(1000); delete p; } } I than monitored the memory consumption of my application using task manager, surprisingly the memory was allocated and freed correctly, allocated memory did not steadily increase as was expected I've modified my test program to allocate a non primitive type array : #include "stdafx.h" #include "Windows.h" struct aStruct { aStruct() : i(1), j(0) {} int i; char j; } NonePrimitive; const unsigned long BLOCK_SIZE = 1024*100000; int _tmain() { for (unsigned int i =0; i < 1024*100000; i++) { aStruct* p = new aStruct[1024*100000]; Sleep(1000); delete p; } } after running for for 10 minutes there was no meaningful increase in memory I compiled the project with warning level 4 and got no warnings. is it possible that the visual studio run time keep track of the allocated objects types so there is no different between delete and delete[] in that environment ?

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