find multiple closest hashes

libi2pd/KadDHT.cpp

@@ -206,6 +206,39 @@ namespace data
 		return nullptr;
 	}	
 
+	std::vector<IdentHash *> DHTTable::FindClosest (const IdentHash& h, size_t num)
+	{
+		std::vector<IdentHash *> vec;
+		if (num > 0)
+			FindClosest (h, num, m_Root, 0, vec);
+		return vec;
+	}	
+
+	void DHTTable::FindClosest (const IdentHash& h, size_t num, DHTNode * root, int level, std::vector<IdentHash *>& hashes)
+	{
+		if (hashes.size () >= num) return;
+		if (root->hash)
+		{	
+			hashes.push_back (root->hash);
+			return;
+		}	
+		int bit = h.GetBit (level);
+		if (bit)
+		{
+			if (root->one)
+				FindClosest (h, num, root->one, level + 1, hashes);
+			if (hashes.size () < num && root->zero)
+				FindClosest (h, num, root->zero, level + 1, hashes);
+		}
+		else
+		{
+			if (root->zero)
+				FindClosest (h, num, root->zero, level + 1, hashes);
+			if (hashes.size () < num && root->one)
+				FindClosest (h, num, root->one, level + 1, hashes);
+		}	
+	}	
+		
 	void DHTTable::Print (std::stringstream& s)
 	{
 		Print (s, m_Root, 0);

libi2pd/KadDHT.h

@@ -11,6 +11,7 @@
 #define KADDHT_H__
 
 #include <memory>
+#include <vector>
 #include <sstream>
 #include "Identity.h"
 
@@ -42,6 +43,7 @@ namespace data
 			DHTNode * Insert (const IdentHash& h);
 			bool Remove (const IdentHash& h);
 			IdentHash * FindClosest (const IdentHash& h);
+			std::vector<IdentHash *> FindClosest (const IdentHash& h, size_t num);
 			
 			void Print (std::stringstream& s);	
 			size_t GetSize () const { return m_Size; };
@@ -51,6 +53,7 @@ namespace data
 			DHTNode * Insert (IdentHash * h, DHTNode * root, int level); // recursive
 			bool Remove (const IdentHash& h, DHTNode * root, int level);
 			IdentHash * FindClosest (const IdentHash& h, DHTNode * root, int level);
+			void FindClosest (const IdentHash& h, size_t num, DHTNode * root, int level, std::vector<IdentHash *>& hashes);
 			void Print (std::stringstream& s, DHTNode * root, int level);	
 			
 		private: