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@rodoufu
rodoufu committed Nov 20, 2018
1 parent 0c72c2e commit c2bcfe2
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165 changes: 165 additions & 0 deletions NeoDataStructure/MPT.cs
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using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace com.github.neoresearch.NeoDataStructure
{
public class MPT
{
private byte[] _rootHash;
private readonly Dictionary<byte[], MPTNode> _db = new Dictionary<byte[], MPTNode>();

public byte[] this[byte[] key]
{
// get => _rootHash == null ? null : Get(_db[_rootHash], ConvertToNibble(key));
get => _rootHash == null ? null : _rootHash;
set
{
var node = _rootHash == null ? null : _db[_rootHash];
if (_rootHash != null && _db.ContainsKey(_rootHash))
{
_db.Remove(_rootHash);
}

_rootHash = Set(node, ConvertToNibble(key), key, value);
}
}

private byte[] ConvertToNibble(byte[] key)
{
var resp = new byte[key.Length * 2];
for (var i = 0; i < key.Length; i++)
{
resp[2 * i] = (byte) (key[i] / 16);
resp[2 * i + 1] = (byte) (key[i] % 16);
}

return resp;
}

public string this[string key]
{
get => Encoding.Default.GetString(this[Encoding.UTF8.GetBytes(key)]);
set => this[Encoding.UTF8.GetBytes(key)] = Encoding.UTF8.GetBytes(value);
}

private byte[] Set(ExtensionNode node, byte[] path, byte[] key, byte[] value)
{
/*
if (path.Length == 0)
{
var newNode = new BranchNode
{
Key = key,
Value = value
};
var nodeHash = Set(newNode, node.Path, node.Key, node.Value);
node = _db[nodeHash];
}
else if (node.Path == path)
{
node.Key = key;
node.Value = value;
}
else if (node.Path[0] == path[0])
{
for (var pos = 0;; pos++)
{
if (pos + 1 != node.Path.Length && pos + 1 != path.Length &&
node.Path[pos + 1] == path[pos + 1]) continue;
var newNode = new MPTNode {Path = path.Take(pos + 1).ToArray()};
var innerHash = Set(new MPTNode(true), node.Path.Skip(pos + 1).ToArray(), node.Key,
node.Value);
var innerNode = _db[innerHash];
_db.Remove(innerHash);
newNode[1] = Set(innerNode, path.Skip(pos + 1).ToArray(), key, value);
node = newNode;
break;
}
}
else
{
var newNode = new MPTNode {Path = path.Take(pos + 1).ToArray()};
var innerHash = Set(new MPTNode(true), node.Path.Skip(pos + 1).ToArray(), node.Key, node.Value);
var innerNode = _db[innerHash];
_db.Remove(innerHash);
newNode[1] = Set(innerNode, path.Skip(pos + 1).ToArray(), key, value);
node = newNode;
}
*/

var tempHash = node.Hash();
_db[tempHash] = node;
return tempHash;
}

private byte[] Set(LeafNode node, byte[] path, byte[] key, byte[] value)
{
var tempHash = node.Hash();
_db[tempHash] = node;
return tempHash;
}

private byte[] Set(BranchNode node, byte[] path, byte[] key, byte[] value)
{
if (path.Length == 0)
{
node.Key = key;
node.Value = value;
}
else
{
var innerHash = node[path[0]];
var innerNode = innerHash != null ? _db[innerHash] : null;
if (innerHash != null && _db.ContainsKey(innerHash))
{
_db.Remove(innerHash);
}

node[path[0]] = Set(innerNode, path.Skip(1).ToArray(), key, value);
}

var tempHash = node.Hash();
_db[tempHash] = node;
return tempHash;
}

private byte[] Set(MPTNode node, byte[] path, byte[] key, byte[] value)
{
if (node == null)
{
node = new LeafNode
{
Path = path,
Key = key,
Value = value
};
}

var tempHash = node.Hash();
_db[tempHash] = node;
return tempHash;
}

public override string ToString() => _rootHash == null ? "{}" : $"{ToString(_db[_rootHash])}";

private string ToString(MPTNode node)
{
if (node is LeafNode || node is ExtensionNode)
{
return node.ToString();
}

var resp = new StringBuilder("{");
for (var i = 0; i < node.Length; i++)
{
if (node[i] != null)
{
resp.Append($"\"{i}\":{ToString(_db[node[i]])}");
}
}

return resp.Append("}").ToString();
}
}
}
86 changes: 86 additions & 0 deletions NeoDataStructure/MPTNode.cs
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using System.Collections.Generic;
using System.Text;

namespace com.github.neoresearch.NeoDataStructure
{
public abstract class MPTNode
{
private const int BranchSize = 18;
private const int ExtensionSize = 2;
private const int LeafSize = 3;

private readonly byte[][] _hashes;
private MPTNode(int size = 0) => _hashes = new byte[size][];

public bool IsBranch => _hashes.Length == BranchSize;
public bool IsExtension => _hashes.Length == ExtensionSize;
public bool IsLeaf => _hashes.Length == LeafSize;


public byte[] this[int index]
{
get => _hashes[index];
set => _hashes[index] = value;
}

public byte[] Path
{
get => _hashes[_hashes.Length - 2];
set => _hashes[_hashes.Length - 2] = value;
}

public byte[] Value
{
get => _hashes[_hashes.Length - 1];
set => _hashes[_hashes.Length - 1] = value;
}

public byte[] Key
{
get => _hashes[_hashes.Length - 2];
set => _hashes[_hashes.Length - 2] = value;
}

public byte[] Next
{
get => _hashes[_hashes.Length - 1];
set => _hashes[_hashes.Length - 1] = value;
}

public byte[] Hash()
{
var bytes = new List<byte>();
for (var i = 0; i < _hashes.Length; i++)
{
bytes.Add((byte) i);
if (_hashes[i] != null)
{
bytes.AddRange(_hashes[i]);
}
}

return new System.Security.Cryptography.SHA256Managed().ComputeHash(bytes.ToArray());
}

public override string ToString()
{
var resp = new StringBuilder("[");
var virgula = false;
for (var i = 0; i < _hashes.Length; i++)
{
resp.Append(virgula ? "," : "")
.Append(IsBranch ? $"{i}:" : "")
.Append($"{_hashes[i].ByteToHexString(false)}");
virgula = true;
}

return resp.Append("]").ToString();
}

public int Length => _hashes.Length;

public static MPTNode BranchNode() => new MPTNode(BranchSize);
public static MPTNode ExtensionNode() => new MPTNode(ExtensionSize);
public static MPTNode LeafNode() => new MPTNode(LeafSize);
}
}
18 changes: 18 additions & 0 deletions NeoDataStructureTest/MPTTest.cs
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namespace com.github.neoresearch.NeoDataStructureTest
{
using System.Collections.Generic;
using NeoDataStructure;
using Xunit;

public class MPTTest
{
[Fact]
public void OperatorEqual()
{
var mp = new MPT();
Assert.False(mp == null);
mp[new byte[] {0, 0, 1}] = new byte[] {0, 0, 1};
mp[new byte[] {0, 0, 2}] = new byte[] {0, 0, 2};
}
}
}

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