TupleAccessor.h

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/*
// $Id: //open/dev/fennel/tuple/TupleAccessor.h#17 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
// Portions Copyright (C) 1999-2009 John V. Sichi
//
// 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_TupleAccessor_Included
#define Fennel_TupleAccessor_Included

#include "fennel/tuple/TupleFormat.h"

#include <boost/dynamic_bitset.hpp>
#include <boost/utility.hpp>
#include <vector>

FENNEL_BEGIN_NAMESPACE

class TupleData;
class TupleDescriptor;
class AttributeAccessor;

// NOTE: see comments on struct StoredNode before modifying the way tuples are
// stored.

class FENNEL_TUPLE_EXPORT TupleAccessor
    : public boost::noncopyable
{
    std::vector<AttributeAccessor *> ppAttributeAccessors;

    VectorOfUint pVarWidthAttrIndices;

    VectorOfUint marshalOrder;

    uint cbMaxStorage;

    uint cbMinStorage;

    uint nBitFields;

    uint iBitFieldOffset;

    uint iFirstVarEndIndirectOffset;

    uint iLastVarEndIndirectOffset;

    uint iFirstVarOffset;

    bool bAlignedVar;

    PConstBuffer pTupleBuf;

    boost::dynamic_bitset<FixedBuffer> bitFields;

    TupleFormat format;

    // private helpers
    void initFixedAccessors(TupleDescriptor const &,VectorOfUint &);
    void clear();

public:
    typedef uint16_t StoredValueOffset;

    static const bool BOOL_TRUE;

    static const bool BOOL_FALSE;

    explicit TupleAccessor();

    virtual ~TupleAccessor();

    void compute(
        TupleDescriptor const &tuple,
        TupleFormat format = TUPLE_FORMAT_STANDARD);

    uint getMaxByteCount() const
    {
        return cbMaxStorage;
    }

    uint getMinByteCount() const
    {
        return cbMinStorage;
    }

    bool isFixedWidth() const
    {
        return isMAXU(iFirstVarOffset);
    }

    uint getBitFieldOffset() const
    {
        return iBitFieldOffset;
    }

    PConstBuffer getCurrentTupleBuf() const
    {
        return pTupleBuf;
    }

    void setCurrentTupleBuf(PConstBuffer pTupleBuf, bool valid = true);

    void resetCurrentTupleBuf();

    inline uint getCurrentByteCount() const;

    uint getBufferByteCount(PConstBuffer pBuf) const;

    uint getByteCount(TupleData const &tuple) const;

    bool isBufferSufficient(TupleData const &tuple,uint cbBuffer) const;

    // TODO:  come up with a common interface for TupleProjectionAccessor, and
    // add an additional virtual interface
    void unmarshal(TupleData &tuple,uint iFirstDatum = 0) const;

    AttributeAccessor const &getAttributeAccessor(uint iAttribute) const
    {
        return *(ppAttributeAccessors[iAttribute]);
    }

    void marshal(TupleData const &tuple,PBuffer pTupleBuf);

    uint size() const
    {
        return ppAttributeAccessors.size();
    }

    // TODO:  private

    boost::dynamic_bitset<FixedBuffer> const &getBitFields() const
    {
        return bitFields;
    }

    StoredValueOffset const *referenceIndirectOffset(uint iIndirectOffset) const
    {
        return referenceIndirectOffset(
            const_cast<PBuffer>(pTupleBuf),
            iIndirectOffset);
    }

    static StoredValueOffset *referenceIndirectOffset(
        PBuffer pTupleBuf,uint iIndirectOffset)
    {
        return reinterpret_cast<StoredValueOffset *>(
            pTupleBuf + iIndirectOffset);
    }
};

inline uint TupleAccessor::getCurrentByteCount() const
{
    assert(pTupleBuf);
    return getBufferByteCount(pTupleBuf);
}

FENNEL_END_NAMESPACE

#endif

// End TupleAccessor.h

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