protected override int DoReplace(int ndxItem, T item)
{
if (ndxItem == m_positions.Count - 1)
{
Writer.Position = m_positions[ndxItem];
var dh = new DatumHolder(item);
dh.Write(Writer);
m_newItemPos = Writer.Position;
}
else
{
Writer.Position = m_positions[ndxItem];
Writer.Write(DELETED_DATUM_TAG);
m_positions.RemoveAt(ndxItem);
Writer.Position = m_newItemPos;
var dh = new DatumHolder(item);
dh.Write(Writer);
m_positions.Add(m_newItemPos);
m_newItemPos = Writer.Position;
++m_header.DataCount;
}
return(m_positions.Count - 1);
}
protected override int DoInsert(T item)
{
Writer.Position = m_newItemPos;
var dh = new DatumHolder(item);
dh.Write(Writer);
m_positions.Add(m_newItemPos);
m_newItemPos = Writer.Position;
++m_header.DataCount;
return(m_positions.Count - 1);
}
protected override void Init()
{
Reader.Position = m_header.DataPosition;
var dh = new DatumHolder(CreateEmptyDatum());
for (int i = 0; i < m_header.DataCount; ++i)
{
long pos = Reader.Position;
dh.Read(Reader);
if (dh.Tag != DELETED_DATUM_TAG)
{
m_positions.Add(pos);
}
}
m_newItemPos = Reader.Position;
}
