public static void CreateEmptyFile(BinaryWriter writer)
{
// Create new header instance
var header = new Header();
header.IndexRootPageID = 0;
header.FreeIndexPageID = 0;
header.FreeDataPageID = uint.MaxValue;
header.LastFreeDataPageID = uint.MaxValue;
header.LastPageID = 0;
HeaderFactory.WriteToFile(header, writer);
// Create a first fixed index page
var pageIndex = new IndexPage(0);
pageIndex.NodeIndex = 0;
pageIndex.NextPageID = uint.MaxValue;
// Create first fixed index node, with fixed middle guid
var indexNode = pageIndex.Nodes[0];
indexNode.ID = new Guid(new byte[] { 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127 });
indexNode.IsDeleted = true;
indexNode.Right = new IndexLink();
indexNode.Left = new IndexLink();
indexNode.DataPageID = uint.MaxValue;
indexNode.FileName = string.Empty;
indexNode.FileExtension = string.Empty;
PageFactory.WriteToFile(pageIndex, writer);
}
public static void WriteToFile(Header header, BinaryWriter writer)
{
// Seek the stream on 0 position to save header
writer.BaseStream.Seek(0, SeekOrigin.Begin);
writer.Write(Header.FileID.ToBytes(Header.FileID.Length));
writer.Write(Header.FileVersion);
writer.Write(header.IndexRootPageID);
writer.Write(header.FreeIndexPageID);
writer.Write(header.FreeDataPageID);
writer.Write(header.LastFreeDataPageID);
writer.Write(header.LastPageID);
}
public Engine(FileStream stream)
{
Reader = new BinaryReader(stream);
if (stream.CanWrite)
{
Writer = new BinaryWriter(stream);
Writer.Lock(Header.LOCKER_POS, 1);
}
Header = new Header();
HeaderFactory.ReadFromFile(Header, this.Reader);
CacheIndexPage = new CacheIndexPage(Reader, Writer, Header.IndexRootPageID);
}
public static void ReadFromFile(Header header, BinaryReader reader)
{
// Seek the stream on 0 position to read header
reader.BaseStream.Seek(0, SeekOrigin.Begin);
// Make same validation on header file
if (reader.ReadString(Header.FileID.Length) != Header.FileID)
throw new FileDBException("The file is not a valid storage archive");
if (reader.ReadInt16() != Header.FileVersion)
throw new FileDBException("The archive version is not valid");
header.IndexRootPageID = reader.ReadUInt32();
header.FreeIndexPageID = reader.ReadUInt32();
header.FreeDataPageID = reader.ReadUInt32();
header.LastFreeDataPageID = reader.ReadUInt32();
header.LastPageID = reader.ReadUInt32();
header.IsDirty = false;
}
