/// <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 BPlusTree SetupFromExistingStream(Stream fromFile, long seekStart)
{
if (fromFile == null)
{
throw new ArgumentNullException("fromFile");
}
BPlusTree tree = new BPlusTree(fromFile, seekStart, 100, 7, (byte)1);
tree.ReadHeader();
tree.BlockFile = BlockFile.SetupFromExistingStream(
fromFile, seekStart + HeaderSize, StorageConstants.BlockFileHeaderPrefix);
if (tree.BlockFile.BlockSize != tree.BlockSize)
{
throw new BPlusTreeException("Inner and outer block sizes should match.");
}
if (tree.RootNodeBlockNumber != StorageConstants.NullBlockNumber)
{
tree.RootNode = BPlusTreeNode.MakeRoot(tree, true);
tree.RootNode.LoadFromBlock(tree.RootNodeBlockNumber);
}
return(tree);
}
