UnalignedAttributeAccessor.h

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/*
// $Id: //open/dev/fennel/tuple/UnalignedAttributeAccessor.h#6 $
// 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) 2006-2009 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
*/

#ifndef Fennel_UnalignedAttributeAccessor_Included
#define Fennel_UnalignedAttributeAccessor_Included

FENNEL_BEGIN_NAMESPACE

class TupleDatum;
class TupleAttributeDescriptor;

class FENNEL_TUPLE_EXPORT UnalignedAttributeAccessor
{
    static const TupleStorageByteLength ONE_BYTE_MAX_LENGTH = 127;
    static const TupleStorageByteLength TWO_BYTE_MAX_LENGTH = 32767;
    static const uint8_t ONE_BYTE_LENGTH_MASK = 0x7f;
    static const uint16_t TWO_BYTE_LENGTH_MASK1 = 0x7f00;
    static const uint16_t TWO_BYTE_LENGTH_MASK2 = 0x00ff;
    static const uint8_t TWO_BYTE_LENGTH_BIT = 0x80;

    uint cbStorage;

    bool omitLengthIndicator;

    bool isCompressedInt64;

    inline void compressInt64(
        TupleDatum const &datum,
        PBuffer pDest) const;

    inline void uncompressInt64(
        TupleDatum &datum,
        PConstBuffer pDataWithLen) const;

    bool isInitialized() const;

public:
    explicit UnalignedAttributeAccessor();

    explicit UnalignedAttributeAccessor(
        TupleAttributeDescriptor const &attrDescriptor);

    void compute(
        TupleAttributeDescriptor const &attrDescriptor);

    void storeValue(
        TupleDatum const &datum,
        PBuffer pDataWithLen) const;

    void loadValue(
        TupleDatum &datum,
        PConstBuffer pDataWithLen) const;

    TupleStorageByteLength getStoredByteCount(
        PConstBuffer pDataWithLen) const;

    TupleStorageByteLength getMaxByteCount() const;
};

FENNEL_END_NAMESPACE

#endif

// End UnalignedAttributeAccessor.h

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