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/*=============================================================================
# Filename: IVStorage.h
# Author: syzz
# Mail: 1181955272@qq.com
# Last Modified: 2015-04-26 16:43
# Description: swap between memory and disk, achieving system-like method
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = */
# ifndef _KVSTORE_IVTREE_STORAGE_IVSTORAGE_H
# define _KVSTORE_IVTREE_STORAGE_IVSTORAGE_H
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# include "../../../Util/VList.h"
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# include "../node/IVIntlNode.h"
# include "../node/IVLeafNode.h"
# include "../heap/IVHeap.h"
//It controls read, write, swap
class IVStorage
{
public :
static const unsigned BLOCK_SIZE = Util : : STORAGE_BLOCK_SIZE ; //fixed size of disk-block
//there are 18 B+Tree indexes and one vstree index, so set 3G buffer size
//static const unsigned long long MAX_BUFFER_SIZE = Util::MAX_BUFFER_SIZE; //max buffer size
//static const unsigned SET_BUFFER_SIZE = 1 << 30; //set buffer size
//static const unsigned HEAP_SIZE = MAX_BUFFER_SIZE / IVNode::INTL_SIZE;
//DEBUG: maybe need to set larger, now the file size is 64G at most
static const unsigned MAX_BLOCK_NUM = 1 < < 24 ; //max block-num
//below two constants: must can be exactly divided by 8
static const unsigned SET_BLOCK_NUM = 1 < < 8 ; //initial blocks num
static const unsigned SET_BLOCK_INC = SET_BLOCK_NUM ; //base of blocks-num inc
static const unsigned SuperNum = MAX_BLOCK_NUM / ( 8 * BLOCK_SIZE ) + 1 ;
//static const unsigned TRANSFER_CAPACITY = BLOCK_SIZE;
//enum ReadType { OVER = 0, EXPAND, NORMAL };
private :
unsigned long long max_buffer_size ;
unsigned heap_size ;
unsigned cur_block_num ;
std : : string filepath ;
unsigned * treeheight ;
BlockInfo * freelist ;
FILE * treefp ; //file: tree nodes
IVHeap * minheap ; //heap of Nodes's pointer, sorted in NF_RK
//very long value list are stored in a separate file(with large block)
//
//NOTICE: according to the summary result, 90% value lists are just below 100 bytes
//<10%: 5000000~100M bytes
VList * value_list ;
//NOTICE: freemem's type is long long here, due to large memory in server.
//However, needmem in handler() and request() is ok to be int/unsigned.
//Because the bstr' size is controlled, so is the node.
unsigned long long freemem ; //free memory to use, non-negative
//unsigned long long time; //QUERY(achieving an old-swap startegy?)
long Address ( unsigned _blocknum ) const ;
unsigned Blocknum ( long address ) const ;
unsigned AllocBlock ( ) ;
void FreeBlock ( unsigned _blocknum ) ;
void ReadAlign ( unsigned * _next ) ;
void WriteAlign ( unsigned * _next , bool & _SpecialBlock ) ;
public :
IVStorage ( ) ;
IVStorage ( std : : string & _filepath , std : : string & _mode , unsigned * _height , unsigned long long _buffer_size , VList * _vlist ) ; //create a fixed-size file or open an existence
bool preRead ( IVNode * & _root , IVNode * & _leaves_head , IVNode * & _leaves_tail ) ; //read and build all nodes, only root in memory
bool readNode ( IVNode * _np , long long * _request ) ; //read, if virtual
bool createNode ( IVNode * & _np ) ; //use fp to create a new node
//NOTICE(if children and child not exist, build children's Nodes)
bool writeNode ( IVNode * _np ) ;
bool readBstr ( Bstr * _bp , unsigned * _next ) ;
bool writeBstr ( const Bstr * _bp , unsigned * _curnum , bool & _SpecialBlock ) ;
bool writeTree ( IVNode * _np ) ;
void updateHeap ( IVNode * _np , unsigned _rank , bool _inheap ) const ;
bool request ( long long _needmem ) ; //deal with memory request
bool handler ( unsigned long long _needmem ) ; //swap some nodes out
//bool update(); //update InMem Node's rank, with clock
~ IVStorage ( ) ;
void print ( std : : string s ) ; //DEBUG
} ;
# endif
