mirror of https://github.com/aria2/aria2
124 lines
4.7 KiB
C++
124 lines
4.7 KiB
C++
/* <!-- copyright */
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/*
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* aria2 - The high speed download utility
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*
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* Copyright (C) 2010 Tatsuhiro Tsujikawa
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* In addition, as a special exception, the copyright holders give
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* permission to link the code of portions of this program with the
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* OpenSSL library under certain conditions as described in each
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* individual source file, and distribute linked combinations
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* including the two.
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* You must obey the GNU General Public License in all respects
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* for all of the code used other than OpenSSL. If you modify
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* file(s) with this exception, you may extend this exception to your
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* version of the file(s), but you are not obligated to do so. If you
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* do not wish to do so, delete this exception statement from your
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* version. If you delete this exception statement from all source
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* files in the program, then also delete it here.
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*/
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/* copyright --> */
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#ifndef D_DHT_BUCKET_TREE_H
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#define D_DHT_BUCKET_TREE_H
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#include "common.h"
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#include <vector>
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#include <memory>
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#include "DHTConstants.h"
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namespace aria2 {
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class DHTBucket;
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class DHTNode;
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// This class represents Kademlia DHT routing tree. The leaf nodes
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// have bucket which contains DHT node. The tree is binary tree but
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// highly unbalanced.
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class DHTBucketTreeNode {
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public:
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// Ctor for internal node
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DHTBucketTreeNode(std::unique_ptr<DHTBucketTreeNode> left,
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std::unique_ptr<DHTBucketTreeNode> right);
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// Ctor for leaf node
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DHTBucketTreeNode(std::shared_ptr<DHTBucket> bucket);
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~DHTBucketTreeNode();
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// Returns child node, left or right, which contains key. If dig is
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// called against leaf node, then returns 0.
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DHTBucketTreeNode* dig(const unsigned char* key);
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bool isInRange(const unsigned char* key) const;
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// Returns true iff this is a leaf node.
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bool leaf() const { return bucket_.get(); }
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const unsigned char* getMaxId() const { return maxId_; }
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const unsigned char* getMinId() const { return minId_; }
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DHTBucketTreeNode* getParent() const { return parent_; }
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DHTBucketTreeNode* getLeft() const { return left_.get(); }
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DHTBucketTreeNode* getRight() const { return right_.get(); }
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const std::shared_ptr<DHTBucket>& getBucket() const { return bucket_; }
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// Splits this object's bucket using DHTBucket::split() and create
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// left and right child node to hold buckets. The bucket of current
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// node is reset so this node becomes internal node after this
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// call.
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void split();
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private:
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// Do not allow copying
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DHTBucketTreeNode(const DHTBucketTreeNode&);
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DHTBucketTreeNode& operator=(const DHTBucketTreeNode&);
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// Reset relation of children and minId_ and maxId_.
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void resetRelation();
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void setParent(DHTBucketTreeNode* parent) { parent_ = parent; }
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DHTBucketTreeNode* parent_;
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std::unique_ptr<DHTBucketTreeNode> left_;
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std::unique_ptr<DHTBucketTreeNode> right_;
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std::shared_ptr<DHTBucket> bucket_;
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unsigned char minId_[DHT_ID_LENGTH];
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unsigned char maxId_[DHT_ID_LENGTH];
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};
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namespace dht {
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// Returns leaf node where key fits between node's min and max ID
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// range.
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DHTBucketTreeNode* findTreeNodeFor(DHTBucketTreeNode* root,
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const unsigned char* key);
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// Returns bucket where key fits between bucket's min and max ID
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// range. This function first use findTreeNodeFor and returns its
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// bucket_.
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std::shared_ptr<DHTBucket> findBucketFor(DHTBucketTreeNode* root,
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const unsigned char* key);
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// Stores most closest K nodes against key in nodes. K is
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// DHTBucket::K. This function may returns less than K nodes because
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// the routing tree contains less than K nodes. The order of nodes is
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// arbitrary. Caller must pass empty nodes.
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void findClosestKNodes(std::vector<std::shared_ptr<DHTNode>>& nodes,
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DHTBucketTreeNode* root, const unsigned char* key);
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// Stores all buckets in buckets.
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void enumerateBucket(std::vector<std::shared_ptr<DHTBucket>>& buckets,
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DHTBucketTreeNode* root);
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} // namespace dht
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} // namespace aria2
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#endif // D_DHT_BUCKET_TREE_H
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