WinAggHistogramStrA.h

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/*
// $Id: //open/dev/fennel/calculator/WinAggHistogramStrA.h#3 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2006-2009 The Eigenbase Project
// Copyright (C) 2006-2009 SQLstream, Inc.
// Copyright (C) 2009-2009 LucidEra, Inc.
//
// 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; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// WinAggHistogram - Windowed Aggregation Histogram object.
*/

#ifndef Fennel_WinAggHistogramStrA_Included
#define Fennel_WinAggHistogramStrA_Included

#include "fennel/tuple/TupleDescriptor.h"
#include "fennel/calculator/CalcCommon.h"
#include "fennel/calculator/SqlString.h"
#include "fennel/common/TraceSource.h"

#include <utility>
#include <set>

FENNEL_BEGIN_NAMESPACE

struct StringDesc : public TupleDatum
{
    TupleStorageByteLength cbStorage;
    StandardTypeDescriptorOrdinal mType;

    StringDesc() {}
    ~StringDesc() {}

    StringDesc(StringDesc const &other)
    {
        copyFrom(other);
    }

    StringDesc& operator = (StringDesc const &other)
    {
        copyFrom(other);
        return *this;
    }


    void copyFrom(StringDesc const &other)
    {
        TupleDatum::copyFrom(other);
        cbStorage = other.cbStorage;
        mType = other.mType;
    }

    char* pointer() const;
    TupleStorageByteLength stringLength() const;

};

class FENNEL_CALCULATOR_EXPORT WinAggHistogramStrA
{
public:
    WinAggHistogramStrA()
        : currentWindow(),
          nullRows(0),
          queue()
    {}

    ~WinAggHistogramStrA()
    {}

    typedef struct _StringDescCompare
    {
        bool operator () (const StringDesc& str1, const StringDesc& str2) const
        {
            if (!str1.isNull() && !str2.isNull()) {
                int32_t result = SqlStrCmp<1,1>(
                    str1.pointer(), str1.stringLength(),
                    str2.pointer(), str2.stringLength());
                return result < 0;
            } else {
                return str2.isNull();
            }
        }
    } StringDescCompare;

    typedef multiset<StringDesc,StringDescCompare> WinAggData;

    typedef deque<StringDesc> WinAggQueue;

    //
    void addRow(RegisterRef<char*>* node);

    //
    void dropRow(RegisterRef<char*>* node);

    void getMin(RegisterRef<char*>* node);

    void getMax(RegisterRef<char*>* node);

    void getFirstValue(RegisterRef<char*>* node);

    void getLastValue(RegisterRef<char*>* node);

protected:
    void setReturnReg(RegisterRef<char*>* dest, const StringDesc& src);

private:
    WinAggData currentWindow;   // Holds the values currently in the window.
    int64_t nullRows;           // Couunt of null entries

    WinAggQueue queue;
};

FENNEL_END_NAMESPACE

#endif

// End WinAggHistogramStrA.h

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