/// <summary>
/// 从指定的流初始化树
/// </summary>
/// <param name="fromFile">指定的流</param>
/// <param name="seekStart">流起始查询点</param>
/// <returns>树</returns>
public static BPlusTreeLong SetupFromExistingStream(Stream fromFile, long seekStart)
{
if (fromFile == null)
{
throw new ArgumentNullException("fromFile");
}
BPlusTreeLong tree = new BPlusTreeLong(fromFile, seekStart, 100, 7, (byte)1); // dummy values for nodesize, keysize
tree.ReadHeader();
tree.BlockFile = BlockFile.SetupFromExistingStream(fromFile, seekStart + HeaderSize, StoredConstants.BlockFileHeaderPrefix);
if (tree.BlockFile.BlockSize != tree.BlockSize)
{
throw new BPlusTreeException("inner and outer block sizes should match");
}
if (tree.RootNodeBlockNumber != StoredConstants.NullBlockNumber)
{
tree.RootNode = BPlusTreeNode.MakeRoot(tree, true);
tree.RootNode.LoadFromBlock(tree.RootNodeBlockNumber);
}
return(tree);
}
/// <summary>
/// 从指定的流初始化链式块文件
/// </summary>
/// <param name="fromFile">指定的流</param>
/// <param name="seekStart">流起始索引点</param>
/// <returns>链式块文件</returns>
public static LinkedFile SetupFromExistingStream(Stream fromFile, long seekStart)
{
LinkedFile file = new LinkedFile(fromFile, seekStart, StoredConstants.LinkedFileHeaderPrefix, 100); // dummy block size for now
file.ReadFileHeader();
file.BlockFile = BlockFile.SetupFromExistingStream(fromFile, seekStart + file.FileHeaderSize, StoredConstants.BlockFileHeaderPrefix);
return(file);
}