LbmMinusExecStream.h

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/*
// $Id: //open/dev/fennel/lucidera/bitmap/LbmMinusExecStream.h#13 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2006-2009 LucidEra, Inc.
// Copyright (C) 2006-2009 The Eigenbase Project
//
// 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
*/

#ifndef Fennel_LbmMinusExecStream_Included
#define Fennel_LbmMinusExecStream_Included

#include "fennel/lucidera/bitmap/LbmBitOpExecStream.h"
#include "fennel/lucidera/bitmap/LbmSeqSegmentReader.h"
#include "fennel/tuple/TupleDataWithBuffer.h"

FENNEL_BEGIN_NAMESPACE

struct LbmMinusExecStreamParams : public LbmBitOpExecStreamParams
{
};

class FENNEL_LBM_EXPORT LbmMinusExecStream
    : public LbmBitOpExecStream
{
    bool subtrahendsDone;

    bool needToRead;

    LcsRid baseRid;

    PBuffer baseByteSeg;

    uint baseLen;

    LcsRid minSubtrahendRid;

    LcsRid maxSubtrahendRid;

    bool advancePending;

    LcsRid advanceSubtrahendRid;

    int advanceSubtrahendInputNo;

    enum MinusInputType {
        UNKNOWN_INPUT = 0,
        EMPTY_INPUT,
        NONEMPTY_INPUT
    };

    MinusInputType inputType;

    LbmSeqSegmentReader minuendReader;

    bool prevTupleValid;

    TupleDataWithBuffer prevTuple;

    bool copyPrefixPending;

    TupleData prefixedBitmapTuple;

    static const uint SUBTRAHEND_BITMAP_SIZE = 32768;

    boost::dynamic_bitset<> subtrahendBitmap;

    bool needSubtrahendRestart;

    ExecStreamResult readMinuendInputAndFlush(
        LcsRid &currRid, PBuffer &currByteSeg, uint &currLen);

    ExecStreamResult readMinuendInput(
        LcsRid &currRid, PBuffer &currByteSeg, uint &currLen);

    int comparePrefixes();
    void restartSubtrahends();
    void copyPrefix();

    ExecStreamResult advanceSingleSubtrahend(int inputNo, LcsRid rid);

    ExecStreamResult advanceSubtrahends(LcsRid baseRid);

    ExecStreamResult minusSegments(
        LcsRid baseRid, PBuffer baseByteSeg, uint baseLen);

    ExecStreamResult findMinInput(int &minInput);

    bool checkNeedForRestart();

    bool canSkipMinus();

protected:
    // override LbmBitOpStream
    bool produceTuple(TupleData bitmapTuple);

public:
    virtual void prepare(LbmMinusExecStreamParams const &params);
    virtual void open(bool restart);
    virtual ExecStreamResult execute(ExecStreamQuantum const &quantum);
    virtual void closeImpl();
};

FENNEL_END_NAMESPACE

#endif

// End LbmMinusExecStream.h

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