/**
* free method declaration
* <P>This method marks space in the database file as free.
* <P><B>Note: </B>If more than MAX_FREE_COUNT free positios then
* they are probably all are too small anyway; so we start a new list
* <P>todo: This is wrong when deleting lots of records
*
* @param r (Row object to be marked free)
* @param pos (Offset in the file this Row was stored at)
* @param length (Size of the Row object to free)
*
* @throws Exception
*/
public void free(Row r, int pos, int length)
{
iFreeCount++;
CacheFree n = new CacheFree();
n.iPos = pos;
n.iLength = length;
if (iFreeCount > MAX_FREE_COUNT)
{
iFreeCount = 0;
}
else
{
n.fNext = fRoot;
}
fRoot = n;
// it's possible to remove roots to
remove(r);
}
/**
* free method declaration
* <P>This method marks space in the database file as free.
* <P><B>Note: </B>If more than MAX_FREE_COUNT free positios then
* they are probably all are too small anyway; so we start a new list
* <P>todo: This is wrong when deleting lots of records
*
* @param r (Row object to be marked free)
* @param pos (Offset in the file this Row was stored at)
* @param length (Size of the Row object to free)
*
* @throws Exception
*/
public void free(Row r, int pos, int length)
{
iFreeCount++;
CacheFree n = new CacheFree();
n.iPos = pos;
n.iLength = length;
if (iFreeCount > MAX_FREE_COUNT)
{
iFreeCount = 0;
}
else
{
n.fNext = fRoot;
}
fRoot = n;
// it's possible to remove roots to
remove(r);
}
/**
* add method declaration
* <P>This method adds a Row to the Cache. It walks the
* list of CacheFree objects to see if there is available space
* to store the new Row, reusing space if it exists, otherwise
* we grow the file.
*
* @param r (Row to be added to Cache)
*
* @throws Exception
*/
public void add(Row r)
{
int size = r.iSize;
CacheFree f = fRoot;
CacheFree last = null;
int i = iFreePos;
while (f != null)
{
if (Trace.TRACE)
{
Trace.stop();
}
// first that is long enough
if (f.iLength >= size)
{
i = f.iPos;
size = f.iLength - size;
if (size < 8)
{
// remove almost empty blocks
if (last == null)
{
fRoot = f.fNext;
}
else
{
last.fNext = f.fNext;
}
iFreeCount--;
}
else
{
f.iLength = size;
f.iPos += r.iSize;
}
break;
}
last = f;
f = f.fNext;
}
r.iPos = i;
if (i == iFreePos)
{
iFreePos += size;
}
int k = i & MASK;
Row before = rData[k];
if (before == null)
{
before = rFirst;
}
r.insert(before);
iCacheSize++;
rData[k] = r;
rFirst = r;
}
/**
* add method declaration
* <P>This method adds a Row to the Cache. It walks the
* list of CacheFree objects to see if there is available space
* to store the new Row, reusing space if it exists, otherwise
* we grow the file.
*
* @param r (Row to be added to Cache)
*
* @throws Exception
*/
public void add(Row r)
{
int size = r.iSize;
CacheFree f = fRoot;
CacheFree last = null;
int i = iFreePos;
while (f != null)
{
if (Trace.TRACE)
{
Trace.stop();
}
// first that is long enough
if (f.iLength >= size)
{
i = f.iPos;
size = f.iLength - size;
if (size < 8)
{
// remove almost empty blocks
if (last == null)
{
fRoot = f.fNext;
}
else
{
last.fNext = f.fNext;
}
iFreeCount--;
}
else
{
f.iLength = size;
f.iPos += r.iSize;
}
break;
}
last = f;
f = f.fNext;
}
r.iPos = i;
if (i == iFreePos)
{
iFreePos += size;
}
int k = i & MASK;
Row before = rData[k];
if (before == null)
{
before = rFirst;
}
r.insert(before);
iCacheSize++;
rData[k] = r;
rFirst = r;
}
