Re: Bug with UNICODE and std::vector?

From:

"Giovanni Dicanio" <giovanniDOTdicanio@REMOVEMEgmail.com>

Newsgroups:

microsoft.public.vc.language

Date:

Mon, 22 Sep 2008 12:24:00 +0200

Message-ID:

<ewhNC2JHJHA.1156@TK2MSFTNGP05.phx.gbl>

I reviewed some lines of your code, I think that there are some problems
with Unicode conversion (for which I suggest CA2W from ATL) and with dynamic
allocations and delete not properly done.

You may want to try this code (I put my comments with a "@@" tag so you can
identify the corrections I proposed in your original code):

<code>

#include <iostream>
#include <vector>
#include <string>

// @@ use CA2W to convert from ANSI to Unicode
#include <atlbase.h>
#include <atlconv.h>

class Basis {
public:
    Basis* pLeft; // I dont use, these pointers were also in the original
program where I got this exception.
    Basis* pRight;

    // @@ Clear pointers in default ctor
    Basis()
        : pLeft(NULL), pRight( NULL )
    {

    }

    // @@ You are inheriting from this class, and storing pointers to
    // this class in the vector container, so I would assign a virtual
    // destructor to this class for proper cleanup
    virtual ~Basis()
    {
        // Nothing to do here
    }
};

class Test1 : public Basis {
public:
    wchar_t cChar;

    Test1(wchar_t c = L'\0') : cChar(c) {}

    virtual ~Test1()
    {
        // Nothing to do here
    }
};

int main(int argc, char* charv[])
{
    // @@ I like typedef'ing templates
    // std::vector<Basis*> vec;
    typedef std::vector< Basis * > BasisPtrVector;
    BasisPtrVector vec;

    char buf[150];
    std::string str;
    std::wstring wstr;

    do {
        // @@ Better not hard-coding numbers for sizes - use sizeof()
        // memset(buf,0,150);
        memset( buf, 0, sizeof(buf) );

        std::cout << "\nEnter: ";
        std::getline(std::cin,str);

        // @@ To convert from ANSI to Unicode, I would use ATL helper
classes:
        CA2W unicodeString( str.c_str() );

        // @@ Convert to STL wstring
        wstr = std::wstring( unicodeString );

        // @@ use ++it for better performance for iterators
// for (std::string::iterator it = str.begin(); it != str.end(); it++)
        for (std::string::iterator it = str.begin(); it != str.end(); ++it)

        {
            vec.push_back( new Test1(*it) );
        }

        for (BasisPtrVector::iterator it = vec.begin(); it !=
            vec.end(); ++it)
        {
            // @@ This code is complicated... and the cast from wchar_t to
char is not good...
            // std::cout << (char)( (Test1*)(*it))->cChar;
            // Use wcout to send Unicode output...
            std::wcout << ( static_cast<Test1 *>(*it) )->cChar;
        }

        std::cout << "\n";

        // @@ You should erase *pointed objects* you allocated with new,
        // before erasing the pointer values stored in the vector
        // vec.erase(vec.begin(),vec.end());
        for ( BasisPtrVector::iterator it = vec.begin(); it != vec.end();
++it )
        {
            delete *it;
        }

        // @@ now you can delete vector content (note that clear() method
erases all).
        vec.clear();

    } while (wstr != L"stop");

    return 0;
}

</code>

HTH,
Giovanni

"Bas" <geenspam@danku.nl> ha scritto nel messaggio
news:48d766ef$0$27217$9a622dc7@news.kpnplanet.nl...

Hello all,
Im not sure, but I get some pretty strange results here.
When I run this program debug compiled but NOT in debug mode, or release
compiled
I get an exception, sometimes immediately, sometimes after some time.
If I run in debug mode, everything runs fine.
I THINK it has something to do with reallocating of the vector if its
capacity is too small.
If I replace all UNICODE stuff with "normal" characters, I don't have any
problem.
anyone the same experience? Or am I doing something wrong?

Bas from Holland

excerpt from memory.h:
void deallocate(pointer _Ptr, size_type)
{ // deallocate object at _Ptr, ignore size
::operator delete(_Ptr); <---- here I get an
exception.
}

the program:
#include <iostream>
#include <vector>
#include <string>

class Basis {
public:
   Basis* pLeft; // I dont use, these pointers were also in the original
program where I got this exception.
   Basis* pRight;
};

class Test1 : public Basis {
public:
   wchar_t cChar;

   Test1(wchar_t c = L'\0') : cChar(c) {}
};

int main(int argc, char* charv[])
{
   std::vector<Basis*> vec;

   char buf[150];
   std::string str;
   std::wstring wstr;

   do {
       memset(buf,0,150);

       std::cout << "\nEnter: ";
       std::getline(std::cin,str);

// I use this to convert the "normal" string in a UNICODE string
       size_t iConverted;
       int strLengte = str.length();
       wchar_t* pBuf = new wchar_t(strLengte +2);
       memset(pBuf,0,strLengte + 3 );
       mbstowcs_s(&iConverted,pBuf,str.length()+1,str.c_str(),_TRUNCATE);
       wstr= std::wstring(pBuf);

       for (std::string::iterator it = str.begin(); it != str.end(); it++)
       {
           vec.push_back(new Test1(*it));
       }

       for (std::vector<Basis*>::iterator it = vec.begin(); it !=
vec.end(); it++)
           std::cout << (char)((Test1*)(*it))->cChar;

       std::cout << "\n";
       vec.erase(vec.begin(),vec.end());
   } while (wstr != L"stop");
   return 0;
}