SegStream.h

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/*
// $Id: //open/dev/fennel/segment/SegStream.h#12 $
// 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_SegStream_Included
#define Fennel_SegStream_Included

#include "fennel/common/ByteStream.h"
#include "fennel/segment/SegPageLock.h"
#include "fennel/common/PseudoUuid.h"

FENNEL_BEGIN_NAMESPACE

// NOTE:  read comments on struct StoredNode before modifying
// SegStreamNode

struct FENNEL_SEGMENT_EXPORT SegStreamNode
    : public StoredNode
{
    static const MagicNumber MAGIC_NUMBER = 0x99f28198d53750a5LL;

    uint cbData;
};

struct FENNEL_SEGMENT_EXPORT SegStreamCrc
{
    PageId pageId;

    PseudoUuid onlineUuid;

    uint64_t checksum;
};

typedef SegNodeLock<SegStreamNode> SegStreamLock;

struct FENNEL_SEGMENT_EXPORT SegStreamPosition
{
    SegByteId segByteId;

    FileSize cbOffset;
};

class FENNEL_SEGMENT_EXPORT SegStream
    : virtual public ByteStream
{
protected:
    SegmentAccessor segmentAccessor;

    SegStreamLock pageLock;

    uint cbPageHeader;

    // implement the ClosableObject interface
    virtual void closeImpl();

    explicit SegStream(SegmentAccessor const &,uint cbExtraHeader);
public:

    virtual void getSegPos(SegStreamPosition &pos) = 0;

    SharedSegment getSegment() const;

    SegmentAccessor const &getSegmentAccessor() const;
};

class FENNEL_SEGMENT_EXPORT SegStreamMarker
    : public ByteStreamMarker
{
    friend class SegInputStream;

    SegStreamPosition segPos;

    explicit SegStreamMarker(SegStream const &segStream);

    // implement ByteStreamMarker
    virtual FileSize getOffset() const;
};

FENNEL_END_NAMESPACE

#endif

// End SegStream.h

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