/// <summary>
/// Construct a tree from given storage, using the specified comparer of key
/// </summary>
/// <param name="keySerializer">Tool to serialize node keys.</param>
/// <param name="valueSerializer">Tool to serialize node values<param>
/// <param name="recordStorage">Underlying tool for storage.</param>
/// <param name="keyComparer">Key comparer.</param>
public TreeDiskNodeManager(ISerializer <K> keySerializer
, ISerializer <V> valueSerializer
, IRecordStorage recordStorage
, IComparer <K> keyComparer)
{
if (recordStorage == null)
{
throw new ArgumentNullException("nodeStorage");
}
this.recordStorage = recordStorage;
this.serializer = new TreeDiskNodeSerializer <K, V>(this, keySerializer, valueSerializer);
this.KeyComparer = keyComparer;
this.EntryComparer = Comparer <Tuple <K, V> > .Create((a, b) =>
{
return(KeyComparer.Compare(a.Item1, b.Item1));
});
// The first record of nodeStorage stores id of root node,
// if this record do not exist at the time this index instanitate,
// then attempt to create it
var firstBlockData = recordStorage.Find(1u);
if (firstBlockData != null)
{
this.rootNode = Find(BufferHelper.ReadBufferUInt32(firstBlockData, 0));
}
else
{
this.rootNode = CreateFirstRoot();
}
}
public uint Deserialize(byte[] buffer, int offset, int length)
{
if (length != 4)
{
throw new ArgumentException("Invalid length: " + length);
}
return(BufferHelper.ReadBufferUInt32(buffer, offset));
}
TreeNode <K, V> VariableKeyLengthDeserialize(uint assignId, byte[] buffer)
{
// First 4 bytes uint32 is parent id
var parentId = BufferHelper.ReadBufferUInt32(buffer, 0);
// Followed by 4 bytes uint32 of by how many entries this node has
var entriesCount = BufferHelper.ReadBufferUInt32(buffer, 4);
// Followed by 4 bytes uint32 of how many child reference this node has
var childrenCount = BufferHelper.ReadBufferUInt32(buffer, 8);
// Deserialize entries
var entries = new Tuple <K, V> [entriesCount];
var p = 12;
for (var i = 0; i < entriesCount; i++)
{
var keyLength = BufferHelper.ReadBufferInt32(buffer, p);
var key = this.keySerializer.Deserialize(buffer
, p + 4
, keyLength);
var value = this.valueSerializer.Deserialize(buffer
, p + 4 + keyLength
, this.valueSerializer.Length);
entries[i] = new Tuple <K, V>(key, value);
p += 4 + keyLength + valueSerializer.Length;
}
// Decode child refs..
var children = new uint[childrenCount];
for (var i = 0; i < childrenCount; i++)
{
// Decode child refs..
children[i] = BufferHelper.ReadBufferUInt32(buffer, (int)(p + (i * 4)));
}
// Reconstuct the node
return(new TreeNode <K, V>(nodeManager, assignId, parentId, entries, children));
}