Linux Cubed Series 3: Developer Tools/Linux Cubed Series 3 - Developer Tools.iso/devel/db/esm-3.1/esm-3/usr/local/sm/src/client/btree/OVPAGE.C

C/C++ Source or Header | 1996-05-05 | 5.0 KB | 215 lines

/*
 * $RCSfile: OVPAGE.C,v $
 * $Revision: 1.1.1.1 $
 * $Date: 1996/05/04 21:55:16 $
 */
/**********************************************************************
* EXODUS Database Toolkit Software
* Copyright (c) 1991 Computer Sciences Department, University of
*                    Wisconsin -- Madison
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* THE COMPUTER SCIENCES DEPARTMENT OF THE UNIVERSITY OF WISCONSIN --
* MADISON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION.
* THE DEPARTMENT DISCLAIMS ANY LIABILITY OF ANY KIND FOR ANY DAMAGES
* WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* The EXODUS Project Group requests users of this software to return
* any improvements or extensions that they make to:
*
*   EXODUS Project Group
*     c/o David J. DeWitt and Michael J. Carey
*   Computer Sciences Department
*   University of Wisconsin -- Madison
*   Madison, WI 53706
*
*     or [e-mail]
*
* In addition, the EXODUS Project Group requests that users grant the
* Computer Sciences Department rights to redistribute these changes.
**********************************************************************/
#include "BTREEPAGE.h"
#include "OVPAGE.h"
#include "sm_macro.h"


void OVPAGE::Init(PID& pid, int es)
{
    ovCtrl.elCnt = 0;
    ovCtrl.elSize = es;
    ovCtrl.maxEl = OV_DATASIZE / es;
    ovCtrl.selfID = pid;
    ovCtrl.next = ovCtrl.prev = NULLPID;
}

//
//    Class        : OVPAGE
//    Method        : void Linkup(OVPAGE* rightPage)
//    Description    : Link this page to rightPage. Update next and prev pointers.
//
void OVPAGE::Linkup(OVPAGE* rightPage)
{
    ovCtrl.next = NULLPID;
    if (rightPage)  {
    rightPage->ovCtrl.prev = ovCtrl.selfID.page;
        ovCtrl.next = rightPage->ovCtrl.selfID.page;
    }
}



//
//    Class        : OVPAGE
//    Method        : void Shift(int start, OVPAGE* destPage)
//    Description    : Shifts all tuples from this page starting
//              from slot 'start' to end of destPage.
//
void OVPAGE::Shift(int start, OVPAGE* destPage)
{
    int cnt = ElCnt() - start;        // # of oids to move

    //
    //    Assert sane parameters
    //
    ASSERT3(start >= 0 && start < ElCnt());
    ASSERT3(destPage->ElCnt() + cnt < MaxEl());
    ASSERT3(destPage->ElSize() == ElSize());

    //
    //    Move it
    //
    void* op1 = destPage->Get(destPage->ovCtrl.elCnt);
    void* op2 = Get(start);
    BCOPY(op2, op1, ElSize() * cnt);

    //
    //    Update control info
    //
    destPage->ovCtrl.elCnt += cnt;
    ovCtrl.elCnt = start;

    ASSERT3(CheckPage());
    ASSERT3(destPage->CheckPage());
}


void OVPAGE::FillSort(int cnt, void* array)
{
    ASSERT3(ovCtrl.elCnt == 0);

    BCOPY(array, Get(0), cnt * ElSize());
    ovCtrl.elCnt = cnt;

    Sort();

    ASSERT3(CheckPage());
}


//
//    Class        : OVPAGE
//    Method        : void Insert(int startSlot, int cnt, void* array)
//    Description    : Insert cnt entries of 'array' into this page starting
//                  at startSlot.
//
void OVPAGE::Insert(int startSlot, int cnt, const void* array)
{
    ASSERT3(startSlot >= 0 && startSlot <= ElCnt());

    //
    //    Make space in oidArray
    //
    if (ElCnt() > startSlot)  {
    BCOPY(Get(startSlot), Get(startSlot + cnt),
          (ElCnt() - startSlot) * ElSize());
    }

    //
    //    Copy into the space in oidArray
    //
    BCOPY(array, Get(startSlot), cnt * ElSize());

    //
    //    Update control info
    //
    ovCtrl.elCnt += cnt;

    ASSERT3(CheckPage());
}


//
//    Class        : OVPAGE
//    Method        : void Remove(int startSlot, int cnt)
//    Description    : Remove cnt entries starting from startSlot
//
void OVPAGE::Remove(int startSlot, int cnt)
{
    ASSERT3(cnt > 0);
    ASSERT3(ElCnt() >= startSlot + cnt);

    //
    //    Close the gap in oidArray
    //
    if (ElCnt() > startSlot + cnt)  {
    BCOPY(Get(startSlot + cnt), Get(startSlot),
          (ElCnt()-(startSlot+cnt)) * ElSize());
    }

    //
    //    Update control info
    //
    ovCtrl.elCnt -= cnt;
    ASSERT3(CheckPage());
}



//
//    Class        : OVPAGE
//    Method        : void Sort()
//    Description    : Sort the oidArray. A hack is needed in order to
//              use the qsort() library routine. The static variable
//              __OVSortElSize is used for this purpose.
//

static int __OVSortElSize = 0;
static int cmp(const void* o1, const void* o2);


void OVPAGE::Sort()
{
    __OVSortElSize = ElSize();                    // used by cmp()
    qsort(Get(0), ElCnt(), ElSize(), cmp);
}


static int cmp(const void* o1, const void* o2)
{
    ASSERT3(__OVSortElSize > 0 && __OVSortElSize <= SM_MAXELEMLEN);
    return BT_ElemDiff(__OVSortElSize, o1, o2);
}



//
//    Class        : OVPAGE
//    Method        : CheckPage()
//    Description    : Checks the content of the page
//
int OVPAGE::CheckPage()
{
    ASSERT1(ElCnt() >= 0);
    for (int i = 0; i < ElCnt() - 1; i++)  {
    ASSERT1(BT_ElemDiff(ElSize(), Get(i), Get(i+1)) < 0);
    }

    return TRUE;
}