CODEWITHSUNDEEP
c++visual-studio-2010vectorcrash
tmighty
tmighty

Reputation: 11399

C++ Adding values to kind of a matrix

I have the following class:

class clsJoinFeeder
{
public:
    vector<vector<unsigned char> > UnsignedChars;
};

Now I would like to add a vector of unsigned chars to the class. I tried to do it like this:

void CBinLoader::LoadJoinFeaturesFromCompiledDat(clsJoinFeeder &uJoinFeeder)
{
    for (unsigned int y=0;y<2;y++)
    {
        for (unsigned int x=0;x<17;x++)
        {
            pLoadSmallFloatMap(uJoinFeeder);
            pLoadBigUnsignedCharMap(uJoinFeeder);
        }
    }
}

void CBinLoader::pLoadBigUnsignedCharMap(clsJoinFeeder &uJoinFeeder)
{
    unsigned int iItemsCount = 0;
    fread(&iItemsCount,sizeof(unsigned int),1,m_infile);

    unsigned long iByteSizeActualData = 0;
    fread(&iByteSizeActualData,sizeof(unsigned long),1,m_infile);

    vector<unsigned char>nChars;
    nChars.resize(iItemsCount+1);

    fread(&nChars[0],iByteSizeActualData,1,m_infile); //works fine. nChars is correctly filled

    uJoinFeeder.UnsignedChars.push_back(nChars); //here the crash occurs
}

It compiles fine, but at runtime it crashes with a heap alloc error in the line:

uJoinFeeder.UnsignedChars.push_back(nChars);

What can I do to resolve the problem? I don't even see my mistake.

Edit:

Thank you for the help! "iByteSizeActualData" was wrong as Mr. Kühl stated.

Upvotes: 0

Views: 61

Answers (2)

Dietmar K&#252;hl
Dietmar K&#252;hl

Reputation: 153840

I would guess that iItemsCount and iByteSizeActualData have different values with the latter being bigger than iItemsCount. Personally, I would invoke fread() as

if (fread(&nChars[0], nChars.size(), 1, m_infile) != nChars.size()) {
    dealWithTheError();
}

(well, I wouldn't call fread() but rather stream.read() but this is a different matter).

Upvotes: 1

digital_revenant
digital_revenant

Reputation: 3324

Try this:

myJoinFeeder.UnsignedChars.push_back(std::vector<unsigned char>(std::begin(nChars), std::end(nChars));

Upvotes: 0

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