/* Copyright (C) 2014 InfiniDB, Inc.
   Copyright (c) 2019 MariaDB Corporation

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; version 2 of
   the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

//  $Id: wf_sum_avg.h 3868 2013-06-06 22:13:05Z xlou $


#ifndef UTILS_WF_SUM_AVG_H
#define UTILS_WF_SUM_AVG_H

#include <set>
#include "windowfunctiontype.h"


namespace windowfunction
{

// T_IN is the data type of the input values.
// T_OUT is the data type we are using for output and internal values    
template<typename T_IN, typename T_OUT>
class WF_sum_avg : public WindowFunctionType
{
public:
    WF_sum_avg(int id, const std::string& name) :
        WindowFunctionType(id, name), fDistinct(id != WF__SUM && id != WF__AVG)
    {
        resetData();
        utils::int128Max(fMax128);
        utils::int128Min(fMin128);
        utils::uint128Max(fMaxu128);
    }

    // pure virtual in base
    void operator()(int64_t b, int64_t e, int64_t c);
    WindowFunctionType* clone() const;
    void resetData();

    static boost::shared_ptr<WindowFunctionType> makeFunction(int, const string&, int, WindowFunctionColumn*);

protected:
    T_IN        fVal;
    T_OUT       fAvg;
    T_OUT       fSum;
    uint64_t    fCount;
    bool        fDistinct;
    std::set<T_IN> fSet;
    int128_t    fMax128;
    int128_t    fMin128;
    uint128_t   fMaxu128;

    void checkSumLimit(long double val, long double sum);
    void checkSumLimit(int128_t val, int128_t sum);
    void checkSumLimit(uint128_t val, uint128_t sum);
    
    int128_t calculateAvg(int128_t sum, uint64_t count, int scale);
    uint128_t calculateAvg(uint128_t sum, uint64_t count, int scale);
    long double calculateAvg(long double sum, uint64_t count, int scale);
};

} // namespace

#endif  // UTILS_WF_SUM_AVG_H

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