Reading multiple serialized objects from a file - c++

Question

While making my Breakout game in MFC I chose to serialize my CBlock objects so the player can make its own "maps" on a level editor I made, everything is fine while saving; everything I do is to serialize all my CBlock objects with a for since I have all my CBlock objects on a vector<CBlock*>. The problem comes when reading the files. The main problem is that my program does not know how to stop reading when the end of the file ends. I've trying most of the bool methods from CArchive. The only one that kinda worked was CArchive::IsLoading() but the problem is that it still continues to read from file despite having reached the end of the file.
CString m_filter = TEXT("Super Breakout Maker Files (*.sbm)|*.sbm|All Files (*.*)|*.*||");
CFile m_loadFile;
CFileDialog m_fileDlg(TRUE, TEXT(".sbm"), TEXT("mylayout"), OFN_HIDEREADONLY, m_filter, NULL, 0, TRUE);
//CFileDialog m_fileDlg(FALSE, TEXT(".sbm"), TEXT("mylayout"), 0, m_filter);
if (m_fileDlg.DoModal() == IDOK)
{
if (m_blockLayout.size() > 0)
{
for (int i = 0; i < m_blockLayout.size(); i++)
{
delete(m_blockLayout[i]);
}
m_blockLayout.clear();
}
m_loadFile.Open(m_fileDlg.GetFileName(), CFile::modeRead);
CArchive m_loadArchive(&m_loadFile, CArchive::load);
while (m_loadArchive.IsLoading()==true)
{
CBlock* block = new CBlock;
block->Serialize(m_loadArchive);
block->AssignBlockType();
block->m_blockState.CreateCompatibleDC(pDC);
LoadBlock(block->m_blockState, m_blockStateArray, block->GetBlockType(), block->GetHits());
m_blockLayout.push_back(block);
}
m_loadArchive.Close();
if (m_blockLayout.size() > 0)
{
MessageBox(TEXT("Your layout was successfully loaded! Resume game to play."), TEXT("Notification"), MB_ICONINFORMATION);
m_pBall->SetInitialPosition(m_ballBMP, m_pBar, m_barBMP);
}
else
{
MessageBox(TEXT("Unable to read file. Corrupted or incompatible data."), TEXT("Notification"), MB_ICONERROR);
}
}
else
{
return;
}
m_loadFile.Close();
This is my loading method, but as I mentioned, the iteration does not know where to end reading.

Answer 1

Couple of simpler options, easiest would be to store how many blocks are in the file as the first thing in the file before your blocks. Read for that many blocks, then exit.
have a predefined block with specific attributes and member variables that is your "End Of File" Block, whenever you read that specific block, you know to discard it and stop reading.
The other alternative is to just have some specific string at the end of all your block data and check the next line after every block is read for that specific string (this would require some pointer variable for your line in the file though)