109 lines
4.5 KiB
C++
109 lines
4.5 KiB
C++
/*=============================================================================
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# Filename: Node.h
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# Author: syzz
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# Mail: 1181955272@qq.com
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# Last Modified: 2015-04-26 16:38
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# Description: basic Node class, father of IntlNode and LeafNode
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=============================================================================*/
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#ifndef _KVSTORE_NODE_H
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#define _KVSTORE_NODE_H
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#include "../../Util/Util.h"
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#include "../../Bstr/Bstr.h"
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class Node //abstract basic class
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{
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public:
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static const unsigned DEGREE = 2 * 63; //the degree of B+ tree
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static const unsigned MAX_CHILD_NUM = DEGREE;
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static const unsigned MIN_CHILD_NUM = DEGREE >> 1;
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static const unsigned MAX_KEY_NUM = MAX_CHILD_NUM - 1; //max key-num
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static const unsigned MIN_KEY_NUM = MIN_CHILD_NUM - 1; //min key-num
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/* diffrent flags for tree-nodes, 32-bit put rank in low-bits means no need to move*/
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static const unsigned NF_IL = 0x80000000; //is leaf
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static const unsigned NF_ID = 0x00080000; //is dirty, in rank-area
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static const unsigned NF_IM = 0x20000000; //in memory, not virtual
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//static const unsigned NF_IV = 0x10000000; //is virtual
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static const unsigned NF_RK = 0x00ffffff; //select-rank, in Storage
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static const unsigned NF_HT = 0xf00000; //height area in rank
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static const unsigned NF_KN = 0x07f000; //NOTICE: decided by DEGREE
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static const unsigned INTL_SIZE = sizeof(Bstr) * MAX_KEY_NUM;
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static const unsigned LEAF_SIZE = 2 * INTL_SIZE;
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protected:
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unsigned store; //store address, the BLock index
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unsigned flag; //NF_RK, NF_IL,NF_ID, NF_IV, propety
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//int num; //totle keys num
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//Node* father; //point to father-node, which must be IntlNode
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Bstr* keys;
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void AllocKeys();
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//void FreeKeys();
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public:
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Node();
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Node(bool isVirtual);
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bool isLeaf() const;
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bool isDirty() const;
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void setDirty();
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void delDirty();
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bool inMem() const;
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void setMem();
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void delMem();
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//bool isVirtual() const;
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//void setVirtual();
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//void delVirtual();
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unsigned getRank() const;
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void setRank(unsigned _rank);
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unsigned getHeight() const;
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void setHeight(unsigned _h);
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unsigned getNum() const;
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bool setNum(int _num);
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bool addNum();
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bool subNum();
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unsigned getStore() const;
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void setStore(unsigned _store);
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unsigned getFlag() const;
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void setFlag(unsigned _flag);
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const Bstr* getKey(int _index) const; //need to check the index
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bool setKey(const Bstr* _key, int _index, bool ifcopy = false);
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bool addKey(const Bstr* _key, int _index, bool ifcopy = false);
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bool subKey(int _index, bool ifdel = false);
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//virtual functions: polymorphic
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virtual Node* getChild(int _index) const { return NULL; };
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virtual bool setChild(Node* _child, int _index) { return true; };
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virtual bool addChild(Node* _child, int _index) { return true; };
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virtual bool subChild(int _index) { return true; };
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virtual Node* getPrev() const { return NULL; };
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virtual Node* getNext() const { return NULL; };
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virtual const Bstr* getValue(int _index) const { return NULL; };
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virtual bool setValue(const Bstr* _value, int _index, bool ifcopy = false) { return true; };
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virtual bool addValue(const Bstr* _value, int _index, bool ifcopy = false) { return true; };
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virtual bool subValue(int _index, bool ifdel = false) { return true;};
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virtual void setPrev(Node* _prev) {};
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virtual void setNext(Node* _next) {};
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virtual void Virtual() = 0;
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virtual void Normal() = 0;
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virtual unsigned getSize() const = 0; //return all memory owned
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virtual Node* split(Node* _father, int _index) = 0;
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virtual Node* coalesce(Node* _father, int _index) = 0;
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virtual void release() = 0; //release the node, only remain necessary information
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virtual ~Node() {};
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virtual void print(std::string s) = 0; //DEBUG(print the Node)
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};
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/*NOTICE(operations in release())
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*To save memory, we can only remain store and flag(childs added for Leaf).
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*However, in this way childs'pointers is ok to change, use Node** or Node*& is also nonsense
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*because the pointer variable may die.
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*Another way is only to release dynamic memory, and store thw whole, read the Bstr only to
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*build. In this way nodes'pointer doesn't change, and operation is simplified, while memory
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*is consumed a bit more. Because Bstrs consume the most memory, and memory-disk swapping is
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*the most time-consuming thing, it seems to be a better way.
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*WARN:when a node is in memory and not deleted, its basic content is always being! If nodes are
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*really too many, this will cause disaster because we can't swap them out until tree is closed!
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*To solve this problem, there should be two types of release-function: one to release Bstr, one
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*to release the whole(pointer is invalid and rebuild problem)
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*/
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#endif
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