SegInputStream.h

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/*
// $Id: //open/dev/fennel/segment/SegInputStream.h#14 $
// 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_SegInputStream_Included
#define Fennel_SegInputStream_Included

#include "fennel/segment/SegStream.h"
#include "fennel/common/ByteInputStream.h"
#include "fennel/segment/SegPageIter.h"

FENNEL_BEGIN_NAMESPACE

class FENNEL_SEGMENT_EXPORT SegInputStream
    : public SegStream, public ByteInputStream
{
protected:
    SegPageIter pageIter;

    PageId currPageId;

    bool shouldDeallocate;

    // implement the ByteInputStream interface
    virtual void readNextBuffer();
    virtual void readPrevBuffer();
    virtual void closeImpl();

    explicit SegInputStream(
        SegmentAccessor const &,PageId,uint cbExtraHeader = 0);

    virtual void lockBuffer();

public:
    static SharedSegInputStream newSegInputStream(
        SegmentAccessor const &segmentAccessor,
        PageId beginPageId = FIRST_LINEAR_PAGE_ID);

    void startPrefetch();

    void endPrefetch();

    void setDeallocate(bool shouldDeallocate);

    bool isDeallocating();

    // implement the SegStream interface
    virtual void getSegPos(SegStreamPosition &pos);

    void seekSegPos(SegStreamPosition const &pos);

    // override ByteInputStream
    virtual SharedByteStreamMarker newMarker();

    // override ByteInputStream
    virtual void mark(ByteStreamMarker &marker);

    // override ByteInputStream
    virtual void reset(ByteStreamMarker const &marker);
};

FENNEL_END_NAMESPACE

#endif

// End SegInputStream.h

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