working with binary files

[DevLip]

I have a few functions I'm using to write values to a binary file. The problem is when I read from the file to retrieve values all I get is the last value written.

The structure I am inserting is:

struct tsDataS
{
	unsigned	ts		: 32;
	unsigned	volID	: 8;
	unsigned	offset	: 32;
};

I calll the function add to insert (update) the value:

bool timestamp::add(tsData &ts)
{

	if(!myDB) return 0;

	//change this to seek for empty spots first
	fstream mFile;
	int location, findRec;

	objKey1.ts = TS_EMPTY;

	//do we have an open entry space?
	findRec = seekLocation(objKey1, TS_TST);//used to determine the record number
	
	mFile.open(myDB,ios::binary|ios::out);
	location = (findRec - 1)*sizeof(ts);

	mFile.seekp (location);//used to determine location of record
	mFile.write((char*)&ts,sizeof(ts));

	//replace old stamp
	if(findRec < DBSize)
	{
		//increment counter
		activeTScount++;
	}

	//need to make a new entry
	else
	{
		//increment counters
		DBSize++;
		activeTScount++;
	}
	return 1;

}

And then add calls this to get the location of any "empty" (TS_EMPTY == ts) values:

int timestamp::seekLocation(tsData &ts, int tok)
//Find a timestamp matching field tok in ts
{

	fstream seekFile;
	int count =0;
	bool found = false;
	seekFile.open(myDB,ios::binary | ios::in);
	seekFile.seekg(0,ios::beg);
	while(seekFile.read((char*)&objKey1,sizeof(objKey1)))
	{
		++count;
	if( tok == TS_VOL )
		if(ts.volID == objKey1.volID)
		{
			found = true;
			break;
		}
	else if ( tok == TS_OFF )
		if(ts.offset == objKey1.offset)
		{
			found = true;
			break;
		}
	else if ( tok == TS_TST )
		if(ts.ts == objKey1.ts)
		{
			found = true;
			break;
		}
	else if ( tok == TS_VOL + TS_OFF )
		if(ts.offset == objKey1.offset && ts.volID == objKey1.volID)
		{
			found = true;
			break;
		}
	}
	seekFile.close();
	
	if(found) return count;
	return count + 1;

}

Also another interesting point is that sizeof(objKey1) == 12 and sizeof(ts) == 4 even thought they are both struct tsDataS which I thought should equal 9??

thanks,
Devan