121 lines
2.9 KiB
C++
121 lines
2.9 KiB
C++
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/*
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----
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This file is part of SECONDO.
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Copyright (C) 2011, University in Hagen, Department of Computer Science,
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Database Systems for New Applications.
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SECONDO 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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SECONDO 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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You should have received a copy of the GNU General Public License
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along with SECONDO{} if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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//[_] [\_]
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*/
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/*
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1.4.3 TupleStore1
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This tuple store used a chache and a relation to store tuples.
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*/
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#include "TupleStore1.h"
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#include "Algebras/Relation-C++/RelationAlgebra.h"
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/*
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~Constructor~
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This constructor creates a new tuple store. The memSize determines the
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size of the used cache in kB.
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*/
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TupleStore1::TupleStore1(const size_t memSize):
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firstElems(), overflow(0),maxMem(0), usedMem(0), useOverflow(false){
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if(memSize>0){
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maxMem = memSize;
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maxMem = maxMem * 1024u;
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}
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}
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/*
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~AppendTuple~
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This function appends a tuple to this tuple store.
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The id of the tuple may be changed or not. To search for a certain
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tuple within this tuple store, only the return value of this funtion
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can be used. Note that the returned tuple ids are not nessecary increasing.
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*/
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TupleId TupleStore1::AppendTuple(Tuple* t){
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assert(t); // don't allow inserting of null pointers
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size_t tm = t->GetMemSize();
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if(!useOverflow){
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if(usedMem + tm < maxMem){
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size_t id = firstElems.size();
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firstElems.push_back(t);
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t->IncReference();
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usedMem += tm;
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return (TupleId) id;
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}
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useOverflow = true; // switch to relation
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}
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// tuple must be inserted into relation
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if(!overflow){
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overflow = new Relation(t->GetTupleType(), true);
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}
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t->PinAttributes();
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overflow->AppendTupleNoLOBs(t);
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TupleId newId = t->GetTupleId();
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return (TupleId) (newId + firstElems.size()-1);
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}
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/*
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~Destructor~
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*/
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TupleStore1::~TupleStore1(){
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if(overflow){
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overflow->DeleteAndTruncate();
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}
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for(size_t i=0; i< firstElems.size();i++){
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firstElems[i]->DeleteIfAllowed();
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}
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firstElems.clear();
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}
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/*
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~GetTuple~
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Retrieves a tuple by id. If no corresponding tuple is found,
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0 is returned.
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*/
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Tuple* TupleStore1::GetTuple(const TupleId tid){
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if(tid < firstElems.size()){ // get from vector
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Tuple* res = firstElems[tid];
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res->IncReference();
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assert(res);
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return res;
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} else {
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return overflow->GetTuple(tid - firstElems.size()+1,false);
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}
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}
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