74 lines
2.8 KiB
C++
74 lines
2.8 KiB
C++
/*=============================================================================
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# Filename: SITree.h
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# Author: syzz
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# Mail: 1181955272@qq.com
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# Last Modified: 2015-04-26 16:44
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# Description: struct and interface of the B+ tree
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=============================================================================*/
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#ifndef _KVSTORE_SITREE_SITREE_H
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#define _KVSTORE_SITREE_SITREE_H
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#include "../../Util/Util.h"
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#include "../../Util/Stream.h"
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#include "node/SINode.h"
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#include "node/SIIntlNode.h"
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#include "node/SILeafNode.h"
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#include "storage/SIStorage.h"
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//NOTICE:not use Stream for this tree, and no need for range query
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class SITree
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{
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private:
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unsigned int height; //0 indicates an empty tree
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SINode* root;
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SINode* leaves_head; //the head of LeafNode-list
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SINode* leaves_tail; //the tail of LeafNode-list
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std::string mode; //BETTER(to use enum)
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SIStorage* TSM; //Tree-Storage-Manage
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//always alloc one more byte than length, then user can add a '\0'
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//to get a real string, instead of new and copy
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//other operations will be harmful to search, so store value in
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//transfer temporally, while length adjusted.
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//TODO: in multi-user case, multiple-search will cause problem,
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//so lock is a must. Add lock to transfer is better than to add
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//lock to every key/value. However, modify requires a lock for a
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//key/value, and multiple search for different keys are ok!!!
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Bstr transfer[3]; //0:transfer value searched; 1:copy key-data from const char*; 2:copy val-data from const char*
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unsigned transfer_size[3];
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std::string storepath;
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std::string filename; //ok for user to change
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/* some private functions */
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std::string getFilePath(); //in UNIX system
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void CopyToTransfer(const char* _str, unsigned _len, unsigned _index);
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void release(SINode* _np) const;
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//tree's operations should be atom(if read nodes)
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//sum the request and send to Storage at last
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//ensure that all nodes operated are in memory
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long long request;
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void prepare(SINode* _np);
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public:
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SITree(); //always need to initial transfer
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SITree(std::string _storepath, std::string _filename, std::string _mode, unsigned long long _buffer_size);
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unsigned int getHeight() const;
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void setHeight(unsigned _h);
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SINode* getRoot() const;
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//insert, search, remove, set
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bool search(const char* _str, unsigned _len, int* _val);
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bool insert(const char* _str, unsigned _len, int _val);
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bool modify(const char* _str, unsigned _len, int _val);
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SINode* find(const Bstr* _key, int* store, bool ifmodify);
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bool remove(const char* _str, unsigned _len);
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bool save();
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~SITree();
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void print(std::string s); //DEBUG(print the tree)
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};
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//NOTICE: need to save tree manually before delete, otherwise will cause problem.
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//(problem range between two extremes: not-modified, totally-modified)
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//After saved, it's ok to continue operations on tree!
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#endif |