public static void ReadFromFile(IndexPage indexPage, BinaryReader reader)
{
// Seek the stream to the fist byte on page
long initPos = reader.Seek(Header.HEADER_SIZE + ((long)indexPage.PageID * BasePage.PAGE_SIZE));
if (reader.ReadByte() != (byte)PageType.Index)
throw new FileDBException("PageID {0} is not a Index Page", indexPage.PageID);
indexPage.NextPageID = reader.ReadUInt32();
indexPage.NodeIndex = reader.ReadByte();
// Seek the stream to end of header data page
reader.Seek(initPos + IndexPage.HEADER_SIZE);
for (int i = 0; i <= indexPage.NodeIndex; i++)
{
var node = indexPage.Nodes[i];
node.ID = reader.ReadGuid();
node.IsDeleted = reader.ReadBoolean();
node.Right.Index = reader.ReadByte();
node.Right.PageID = reader.ReadUInt32();
node.Left.Index = reader.ReadByte();
node.Left.PageID = reader.ReadUInt32();
node.DataPageID = reader.ReadUInt32();
node.FileName = reader.ReadString(IndexNode.FILENAME_SIZE);
node.FileExtension = reader.ReadString(IndexNode.FILE_EXTENSION_SIZE);
node.FileLength = reader.ReadUInt32();
}
}
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 IndexPage GetFreeIndexPage()
{
var freeIndexPage = CacheIndexPage.GetPage(Header.FreeIndexPageID);
// Check if "free page" has no more index to be used
if (freeIndexPage.UsedNodeCount >= IndexPage.NODES_PER_PAGE - 1)
{
Header.LastPageID++; // Take last page and increase
Header.IsDirty = true;
var newIndexPage = new IndexPage(Header.LastPageID); // Create a new index page
freeIndexPage.NextPageID = newIndexPage.PageID; // Point older page to the new page
Header.FreeIndexPageID = Header.LastPageID; // Update last index page
CacheIndexPage.AddPage(freeIndexPage, true);
return newIndexPage;
}
else
{
// Has more free index on same index page? return them
freeIndexPage.IncNodeUsed(); // Reserve space
return freeIndexPage;
}
}
public const int INDEX_NODE_SIZE = 81; // Node Index size
#endregion Fields
#region Constructors
public IndexNode(IndexPage indexPage)
{
ID = Guid.Empty;
IsDeleted = true; // Start with index node mark as deleted. Update this after save all stream on disk
Right = new IndexLink();
Left = new IndexLink();
DataPageID = uint.MaxValue;
IndexPage = indexPage;
}
public static void WriteToFile(IndexPage indexPage, BinaryWriter writer)
{
// Seek the stream to the fist byte on page
long initPos = writer.SetWritePos(Header.FILE_START_HEADER_SIZE + (indexPage.PageID * BasePage.PAGE_SIZE));
// Write page header
writer.Write((byte)indexPage.Type);
writer.Write(indexPage.NextPageID);
writer.Write(indexPage.UsedNodeCount);
// Seek the stream to end of header index page
writer.SetWritePos(initPos + IndexPage.INDEX_HEADER_SIZE); //46
for (int i = 0; i <= indexPage.UsedNodeCount; i++)
{
var node = indexPage.Nodes[i];
writer.Write(node.ID); //16
writer.Write(node.IsDeleted); //1
writer.Write(node.Right.Index); //1
writer.Write(node.Right.PageID); //4
writer.Write(node.Left.Index);//1
writer.Write(node.Left.PageID); //4
writer.Write(node.DataPageID); //4
writer.Write(node.FileMetaDataLength); //2
writer.Write(node.FileLength); //4
byte[] fileUrlBytes = System.Text.Encoding.UTF8.GetBytes(node.FileUrl);
if (fileUrlBytes.Length >= ushort.MaxValue)
{
throw new FileDBException("filename is too long!");
}
int diff = fileUrlBytes.Length - IndexNode.FILENAME_SIZE;
if (diff >= 0)
{
//limit
writer.Write((byte)(IndexNode.FILENAME_SIZE + 1)); //1
writer.Write(fileUrlBytes, 0, IndexNode.FILENAME_SIZE);
}
else
{
writer.Write((byte)(fileUrlBytes.Length));
writer.Write(fileUrlBytes);
//diff
//write padding
writer.Write(new byte[-diff]);
}
}
}
public static void ReadFromFile(IndexPage indexPage, BinaryReader reader)
{
// Seek the stream to the first byte on page
long initPos = reader.SetReadPos(Header.FILE_START_HEADER_SIZE + (indexPage.PageID * BasePage.PAGE_SIZE));
if (reader.ReadByte() != (byte)PageType.Index)
throw new FileDBException("PageID {0} is not a Index Page", indexPage.PageID);
indexPage.NextPageID = reader.ReadUInt32();
indexPage.SetUsedNodeCount(reader.ReadByte());
// Seek the stream to end of header data page
reader.SetReadPos(initPos + IndexPage.INDEX_HEADER_SIZE);
//in this version
//each node uses buffer= 16+1+1+4+1+4+4+8+4+2+36 =81
//IndexPage.NODES_PER_PAGE = 50;
//so it use 81*50 = 4050
//IndexPage.INDEX_HEADER_SIZE =46
//so => 4050 +46 = 4096
//and each page has BasePage.PAGE_SIZE = 4096 => matched
for (int i = 0; i <= indexPage.UsedNodeCount; i++)
{
var node = indexPage.Nodes[i];
node.ID = reader.ReadGuid(); //16
node.IsDeleted = reader.ReadBoolean(); //1
node.Right.Index = reader.ReadByte(); //1
node.Right.PageID = reader.ReadUInt32(); //4
node.Left.Index = reader.ReadByte(); //1
node.Left.PageID = reader.ReadUInt32();//4
node.DataPageID = reader.ReadUInt32();//4
node.FileMetaDataLength = reader.ReadUInt16();//2
node.FileLength = reader.ReadUInt32();//4
int filenameCount = reader.ReadByte(); //1
if (filenameCount > IndexNode.FILENAME_SIZE)
{
node.FileUrl = reader.ReadUtf8String(IndexNode.FILENAME_SIZE);
}
else
{
string filename = reader.ReadUtf8String(IndexNode.FILENAME_SIZE);
node.FileUrl = filename.Substring(0, filenameCount);
}
}
}
public void AddPage(IndexPage indexPage, bool markAsDirty)
{
if(!_cache.ContainsKey(indexPage.PageID))
{
if(_cache.Count >= CACHE_SIZE)
{
// Remove fist page that are not the root page (because I use too much)
var pageToRemove = _cache.First(x => x.Key != _rootPageID);
if (pageToRemove.Value.IsDirty)
{
PageFactory.WriteToFile(pageToRemove.Value, _writer);
pageToRemove.Value.IsDirty = false;
}
_cache.Remove(pageToRemove.Key);
}
_cache.Add(indexPage.PageID, indexPage);
}
if(markAsDirty)
indexPage.IsDirty = true;
}
public static void ReadFromFile(IndexPage indexPage, BinaryReader reader)
{
// Seek the stream to the fist byte on page
long initPos = reader.Seek(Header.HEADER_SIZE + ((long)indexPage.PageID * BasePage.PAGE_SIZE));
if (reader.ReadByte() != (byte)PageType.Index)
{
throw new FileDBException("PageID {0} is not a Index Page", indexPage.PageID);
}
indexPage.NextPageID = reader.ReadUInt32();
indexPage.NodeIndex = reader.ReadByte();
// Seek the stream to end of header data page
reader.Seek(initPos + IndexPage.HEADER_SIZE);
for (int i = 0; i <= indexPage.NodeIndex; i++)
{
var node = indexPage.Nodes[i];
node.ID = reader.ReadGuid();
node.IsDeleted = reader.ReadBoolean();
node.Right.Index = reader.ReadByte();
node.Right.PageID = reader.ReadUInt32();
node.Left.Index = reader.ReadByte();
node.Left.PageID = reader.ReadUInt32();
node.DataPageID = reader.ReadUInt32();
node.FileName = reader.ReadString(IndexNode.FILENAME_SIZE);
node.FileExtension = reader.ReadString(IndexNode.FILE_EXTENSION_SIZE);
node.FileLength = reader.ReadUInt32();
}
}
public void AddPage(IndexPage indexPage)
{
AddPage(indexPage, false);
}
public static IndexNode GetRootIndexNode(Engine engine)
{
IndexPage rootIndexPage = engine.CacheIndexPage.GetPage(engine.Header.IndexRootPageID);
return(rootIndexPage.Nodes[0]);
}
public static void WriteToFile(IndexPage indexPage, BinaryWriter writer)
{
// Seek the stream to the fist byte on page
long initPos = writer.Seek(Header.HEADER_SIZE + ((long)indexPage.PageID * BasePage.PAGE_SIZE));
// Write page header
writer.Write((byte)indexPage.Type);
writer.Write(indexPage.NextPageID);
writer.Write(indexPage.NodeIndex);
// Seek the stream to end of header index page
writer.Seek(initPos + IndexPage.HEADER_SIZE);
for (int i = 0; i <= indexPage.NodeIndex; i++)
{
var node = indexPage.Nodes[i];
writer.Write(node.ID);
writer.Write(node.IsDeleted);
writer.Write(node.Right.Index);
writer.Write(node.Right.PageID);
writer.Write(node.Left.Index);
writer.Write(node.Left.PageID);
writer.Write(node.DataPageID);
writer.Write(node.FileName.ToBytes(IndexNode.FILENAME_SIZE));
writer.Write(node.FileExtension.ToBytes(IndexNode.FILE_EXTENSION_SIZE));
writer.Write(node.FileLength);
}
}
public static IndexPage GetIndexPage(uint pageID, BinaryReader reader)
{
var indexPage = new IndexPage(pageID);
ReadFromFile(indexPage, reader);
return indexPage;
}
public void AddPage(IndexPage indexPage)
{
AddPage(indexPage, false);
}
