private void Open(string filename)
{
this._fs = new FileStream(filename, FileMode.Open);
this._br = new BinaryReader(this._fs);
this.Header = new TableHeader();
this.Header.BinRead(this._br);
this.Columns = new List<Column>();
for (Int16 i = 0; i < this.Header.ColumnCount; i++)
{
Column c = new Column();
c.BinRead(_br);
this.Columns.Add(c);
}
// Read mysterious extra byte; found in original test
// table from a Lotus Approach database.
_br.ReadByte();
// Sanity check row size
if (this.CalculateTotalRowSize() != this.Header.RowLength)
{
throw new BadDataException("Total size of columns does not match that defined in the header");
}
}
// <summary>
// This method is intended to be used only when
// creating a new table. So; e.g. not for normal writes.
// </summary>
public void CommitToDisk(string filename)
{
// Check that the file doesn't already exist
if (File.Exists(filename))
{
throw new InvalidOperationException("Commit is for writing new tables only; and the filename allocated for this table already exists");
}
// Use a temporary handle, it will be re-opened when we retrieve from it
using (FileStream newTableStream = new FileStream(filename, FileMode.CreateNew))
{
BinaryWriter bw = new BinaryWriter(newTableStream);
// Write the header
this.Header = new TableHeader();
this.Header.Size = (short)((this.Columns.Count + 1) * 32);
this.Header.RowCount = 0;
this.Header.RowLength = (short)this.CalculateTotalRowSize();
this.Header.BinWrite(bw);
foreach (Column c in this.Columns)
{
c.BinWrite(bw);
}
// Add mysterious extra byte
bw.Write(new byte[1]);
bw.Close();
}
}
