countQuery.h

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//File: $Id$
// Author: John Wu <John.Wu at ACM.org>
//         Lawrence Berkeley National Laboratory
// Copyright 2008-2011 the Regents of the University of California
#ifndef IBIS_COUNTQUERY_H
#define IBIS_COUNTQUERY_H



#include "part.h"       // class part
#include "whereClause.h"        // ibis::whereClause

namespace ibis {
    class countQuery;
}

class FASTBIT_CXX_DLLSPEC ibis::countQuery {
public:
    virtual ~countQuery() {clear();}
    countQuery(const part* et=0, const ibis::selectClause *s=0)
        : mypart(et), m_sel(s), hits(0), cand(0) {};

    int setWhereClause(const char *str);
    int setWhereClause(const ibis::qExpr*);
    const char* getWhereClause() const {return conds.getString();}
    int setPartition(const ibis::part* tbl);
    const part* getPartition() const {return mypart;}
    int setSelectClause(const ibis::selectClause *s);
    const selectClause* getSelectClause() const {return m_sel;}

    int estimate();
    long getMinNumHits() const;
    long getMaxNumHits() const;

    int evaluate();
    long getNumHits() const;
    long getHitRows(std::vector<uint32_t> &rids) const;
    const ibis::bitvector* getHitVector() const {return hits;}

    void clear();

protected:
    whereClause conds;  
    const part* mypart; 
    const selectClause *m_sel;  
    ibis::bitvector* hits;
    ibis::bitvector* cand;

    void doEstimate(const qExpr* term, ibis::bitvector& low,
                    ibis::bitvector& high) const;
    int doEvaluate(const qExpr* term, const ibis::bitvector& mask,
                   ibis::bitvector& hits) const;
    int doScan(const ibis::qExpr* term, const ibis::bitvector& mask,
               ibis::bitvector& ht) const;

private:
    countQuery(const countQuery&);
    countQuery& operator=(const countQuery&);
}; // class ibis::countQuery

inline int ibis::countQuery::setSelectClause(const ibis::selectClause *s) {
    if (s == 0) return -1;
    m_sel = s;
    return 0;
} // ibis::countQuery::setSelectClause
#endif // IBIS_COUNTQUERY_H