CompoundId.h

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/*
// $Id: //open/dev/fennel/common/CompoundId.h#11 $
// 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_CompoundId_Included
#define Fennel_CompoundId_Included

FENNEL_BEGIN_NAMESPACE

// NOTE:  read the comment on struct StoredNode before
// modifying the encoding below

class FENNEL_COMMON_EXPORT CompoundId
{
     // masks for extracting portions of a PageId, BlockId, or SegByteId
    static const uint64_t DEVICE_ID_MASK =   0xFFF0000000000000ULL;
    static const uint64_t BYTE_OFFSET_MASK = 0x000FFFFF00000000ULL;
    static const uint64_t BLOCK_NUM_MASK =   0x00000000FFFFFFFFULL;

    static const uint DEVICE_ID_SHIFT = 52;

    static const uint BYTE_OFFSET_SHIFT = 32;

public:
    static const uint MAX_DEVICES = 0x1000;

    static const uint MAX_BYTE_OFFSET = 0xFFFFF;

    template <class PageOrBlockId>
    static BlockNum getBlockNum(PageOrBlockId pageId)
    {
        return (opaqueToInt(pageId) & BLOCK_NUM_MASK);
    }

    template <class PageOrBlockId>
    static void setBlockNum(PageOrBlockId &pageId,BlockNum blockNum)
    {
        assert(blockNum == (blockNum & BLOCK_NUM_MASK));
        pageId = PageOrBlockId(
            (opaqueToInt(pageId) & DEVICE_ID_MASK) | blockNum);
    }

    template <class PageOrBlockId>
    static void incBlockNum(PageOrBlockId &pageId)
    {
        setBlockNum(pageId,getBlockNum(pageId) + 1);
    }

    template <class PageOrBlockId>
    static void decBlockNum(PageOrBlockId &pageId)
    {
        setBlockNum(pageId,getBlockNum(pageId) - 1);
    }

    template <class PageOrBlockId>
    static DeviceId getDeviceId(PageOrBlockId pageId)
    {
        return DeviceId(
            (opaqueToInt(pageId) & DEVICE_ID_MASK) >> DEVICE_ID_SHIFT);
    }

    template <class PageOrBlockId>
    static void setDeviceId(PageOrBlockId &pageId,DeviceId deviceId)
    {
        assert(opaqueToInt(deviceId) < MAX_DEVICES);
        pageId = PageOrBlockId(
            (uint64_t(opaqueToInt(deviceId)) << DEVICE_ID_SHIFT)
            | getBlockNum(pageId));
    }

    static PageId getPageId(SegByteId segByteId)
    {
        return PageId(opaqueToInt(segByteId) & ~BYTE_OFFSET_MASK);
    }

    static void setPageId(SegByteId &segByteId,PageId pageId)
    {
        segByteId = SegByteId(
            opaqueToInt(pageId)
            | (opaqueToInt(segByteId) & BYTE_OFFSET_MASK));
    }

    static uint getByteOffset(SegByteId segByteId)
    {
        return (opaqueToInt(segByteId) & BYTE_OFFSET_MASK) >> BYTE_OFFSET_SHIFT;
    }

    static void setByteOffset(SegByteId &segByteId,uint offset)
    {
        assert(offset == (offset & (BYTE_OFFSET_MASK >> BYTE_OFFSET_SHIFT)));
        segByteId = SegByteId(
            opaqueToInt(getPageId(segByteId))
            | (SegByteIdPrimitive(offset) << BYTE_OFFSET_SHIFT));
    }

    static int comparePageIds(PageId p1,PageId p2)
    {
        return (p1 > p2) ? 1
            : ((p1 < p2) ? -1 : 0);
    }

    static int compareSegByteIds(SegByteId t1,SegByteId t2)
    {
        return (t1 > t2) ? 1
            : ((t1 < t2) ? -1 : 0);
    }

    static uint getMaxDeviceCount()
    {
        return MAX_DEVICES;
    }
};

FENNEL_END_NAMESPACE

#endif

// End CompoundId.h

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