🚀 go-pugleaf

Hi,
I'm testing out memory mapped files and are having some trouble.
I have a test program where I write bytes to a memory mapped file. Everything 
works if I'm using a "view" which is full the size of the file or exactly half 
of it. But if I'm setting the view to a quarter or less, the writing of the file 
fails, after moving the view first time.

Well, I don't get an error from windows, but inspecting the file reveals that 
the writing is not correct.


I have the following code setting up the file
const int ONE_MB =	1048576;
unsigned int fSize      = (unsigned int) 1024 * ONE_MB; //in bytes
unsigned int bytesToMap = fSize/2;
	

CMemoryMappedFile mmFile;	//Encapsulate win32 system calls
CFile file(CString("DiskFile"), CFile::modeReadWrite|
				CFile::modeCreate|
				CFile::shareDenyNone);

	
if(!mmFile.Open(CString("MapFile"),
		(HANDLE) file.m_hFile,
		PAGE_READWRITE,
		0,
		fSize,
		bytesToMap))
{
	cout<<"Failed opening file";
	return 0;
}

The writing to file code is shown below...

unsigned int bytesWrittenInView = 0;
unsigned int totalBytesWritten = 0;	
for(unsigned int i = 0; i < fSize/4; i++) //each write is four bytes
{	
	mmFile.Write((const void*) &i, sizeof(unsigned int));		
	bytesWrittenInView	+= sizeof(unsigned int);
	totalBytesWritten	+= sizeof(unsigned int);
	
	if(totalBytesWritten == fSize)
	{
		cout<<"Finished writing. Wrote "<<totalBytesWritten<<" bytes\n";
		break;
	} 	
			
	if(bytesWrittenInView == bytesToMap)
	{
			
	 	if(!mmFile.UnmapViewOfFile())
	 	{
		 cout<<"Failed to unmap\n";
	 	}
			
		//move the view forward...
		if(!mmFile.MapViewOfFile(FILE_MAP_WRITE, 0, bytesWrittenInView,   			bytesToMap))
		{
			cout<<"Failed changing the view\n";
			break;
		}
		else
		{
			cout<<"Changed view..\n";
		}
			
		bytesWrittenInView = 0;
	}
			
}

Can't really find whats wrong, any clues?
-totte