75 lines
3.3 KiB
C++
75 lines
3.3 KiB
C++
/*=============================================================================
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# Filename: Storage.h
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# Author: syzz
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# Mail: 1181955272@qq.com
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# Last Modified: 2015-04-26 16:43
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# Description: swap between memory and disk, achieving system-like method
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=============================================================================*/
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#ifndef _KVSTORE_STORAGE_STORAGE_H
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#define _KVSTORE_STORAGE_STORAGE_H
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#include "../node/IntlNode.h"
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#include "../node/LeafNode.h"
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#include "../heap/Heap.h"
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//It controls read, write, swap
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class Storage
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{
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public:
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static const unsigned BLOCK_SIZE = Util::STORAGE_BLOCK_SIZE; //fixed size of disk-block
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//there are 18 B+Tree indexes and one vstree index, so set 3G buffer size
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//static const unsigned long long MAX_BUFFER_SIZE = 0xC0000000; //max buffer size
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//static const unsigned long long MAX_BUFFER_SIZE = 0x1ffffffff; //max buffer size
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//NOTICE:this is 1G(ok for most cases), use 2* if need more
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static const unsigned long long MAX_BUFFER_SIZE = Util::MAX_BUFFER_SIZE * 2; //max buffer size
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//static const unsigned SET_BUFFER_SIZE = 1 << 30; //set buffer size
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static const unsigned HEAP_SIZE = MAX_BUFFER_SIZE/Node::INTL_SIZE;
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static const unsigned MAX_BLOCK_NUM = Util::MAX_BLOCK_NUM; //max block-num
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//below two constants: must can be exactly divided by 8
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static const unsigned SET_BLOCK_NUM = 1 << 3; //initial blocks num
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static const unsigned SET_BLOCK_INC = SET_BLOCK_NUM; //base of blocks-num inc
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static const unsigned SuperNum = MAX_BLOCK_NUM/(8*BLOCK_SIZE)+1;
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//static const unsigned TRANSFER_CAPACITY = BLOCK_SIZE;
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//enum ReadType { OVER = 0, EXPAND, NORMAL };
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private:
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unsigned cur_block_num;
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std::string filepath;
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unsigned* treeheight;
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BlockInfo* freelist;
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FILE* treefp; //file: tree nodes
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Heap* minheap; //heap of Nodes's pointer, sorted in NF_RK
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//NOTICE: freemem's type is long long here, due to large memory in server.
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//However, needmem in handler() and request() is ok to be int/unsigned.
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//Because the bstr' size is controlled, so is the node.
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unsigned long long freemem; //free memory to use, non-negative
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//unsigned long long time; //QUERY(achieving an old-swap startegy?)
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long Address(unsigned _blocknum) const;
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unsigned Blocknum(long address) const;
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unsigned AllocBlock();
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void FreeBlock(unsigned _blocknum);
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void ReadAlign(unsigned* _next);
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void WriteAlign(unsigned* _next, bool& _SpecialBlock);
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public:
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Storage();
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Storage(std::string& _filepath, std::string& _mode, unsigned* _height);//create a fixed-size file or open an existence
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bool preRead(Node*& _root, Node*& _leaves_head, Node*& _leaves_tail); //read and build all nodes, only root in memory
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bool readNode(Node* _np, long long* _request); //read, if virtual
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bool createNode(Node*& _np); //use fp to create a new node
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//NOTICE(if children and child not exist, build children's Nodes)
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bool writeNode(Node* _np);
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bool readBstr(Bstr* _bp, unsigned* _next);
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bool writeBstr(const Bstr* _bp, unsigned* _curnum, bool& _SpecialBlock);
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bool writeTree(Node* _np);
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void updateHeap(Node* _np, unsigned _rank, bool _inheap) const;
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void request(long long _needmem); //deal with memory request
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bool handler(unsigned long long _needmem); //swap some nodes out
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//bool update(); //update InMem Node's rank, with clock
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~Storage();
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void print(std::string s); //DEBUG
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};
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#endif
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