/// <summary>
/// Free method declaration.
/// This method marks space in the database file as free.
/// </summary>
/// <remarks>
/// If more than MAX_FREE_COUNT free positios then
/// they are probably all are too small anyway; so we start a new list.
/// TODO: This is wrong when deleting lots of records.
/// </remarks>
///
/// <param name="row">Row object to be marked free</param>
/// <param name="pos">Offset in the file this Row was stored at</param>
/// <param name="length">Size of the Row object to free</param>
public void Free(Row row, int pos, int length)
{
_freeCount++;
CacheFree n = new CacheFree();
n.Pos = pos;
n.Length = length;
if (_freeCount > MAX_FREE_COUNT)
{
_freeCount = 0;
}
else
{
n.Next = _cacheRoot;
}
_cacheRoot = n;
// it's possible to remove roots to
Remove(row);
}
/// <summary>
/// Add method declaration.
/// 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.
/// </summary>
/// <param name="row">Row to be added to Cache</param>
public void Add(Row row)
{
int size = row.Size;
CacheFree f = _cacheRoot;
CacheFree last = null;
int i = _freePos;
while (f != null)
{
if (TracingHelper.TraceEnabled)
{
TracingHelper.Stop();
}
// first that is long enough
if (f.Length >= size)
{
i = f.Pos;
size = f.Length - size;
if (size < 8)
{
// remove almost empty blocks
if (last == null)
{
_cacheRoot = f.Next;
}
else
{
last.Next = f.Next;
}
_freeCount--;
}
else
{
f.Length = size;
f.Pos += row.Size;
}
break;
}
last = f;
f = f.Next;
}
row.Pos = i;
if (i == _freePos)
{
_freePos += size;
}
int k = i & MASK;
Row before = _rowData[k];
if (before == null)
{
before = _rowFirst;
}
row.Insert(before);
_cacheSize++;
_rowData[k] = row;
_rowFirst = row;
}
/// <summary>
/// Free method declaration.
/// This method marks space in the database file as free.
/// </summary>
/// <remarks>
/// If more than MAX_FREE_COUNT free positios then
/// they are probably all are too small anyway; so we start a new list.
/// TODO: This is wrong when deleting lots of records.
/// </remarks>
///
/// <param name="row">Row object to be marked free</param>
/// <param name="pos">Offset in the file this Row was stored at</param>
/// <param name="length">Size of the Row object to free</param>
public void Free(Row row, int pos, int length)
{
_freeCount++;
CacheFree n = new CacheFree();
n.Pos = pos;
n.Length = length;
if (_freeCount > MAX_FREE_COUNT)
_freeCount = 0;
else
n.Next = _cacheRoot;
_cacheRoot = n;
// it's possible to remove roots to
Remove(row);
}
/// <summary>
/// Add method declaration.
/// 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.
/// </summary>
/// <param name="row">Row to be added to Cache</param>
public void Add(Row row)
{
int size = row.Size;
CacheFree f = _cacheRoot;
CacheFree last = null;
int i = _freePos;
while (f != null)
{
if (TracingHelper.TraceEnabled)
{
TracingHelper.Stop();
}
// first that is long enough
if (f.Length >= size)
{
i = f.Pos;
size = f.Length - size;
if (size < 8)
{
// remove almost empty blocks
if (last == null)
{
_cacheRoot = f.Next;
}
else
{
last.Next = f.Next;
}
_freeCount--;
}
else
{
f.Length = size;
f.Pos += row.Size;
}
break;
}
last = f;
f = f.Next;
}
row.Pos = i;
if (i == _freePos)
{
_freePos += size;
}
int k = i & MASK;
Row before = _rowData[k];
if (before == null)
{
before = _rowFirst;
}
row.Insert(before);
_cacheSize++;
_rowData[k] = row;
_rowFirst = row;
}