492 lines
16 KiB
C++
492 lines
16 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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//
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// Microsoft WMIOLE DB Provider
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// (C) Copyright 1999 Microsoft Corporation. All Rights Reserved.
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//
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// CInstanceRowFetchObj object implementation
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//
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//
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///////////////////////////////////////////////////////////////////////////////////
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#include "headers.h"
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#include "WmiOleDBMap.h"
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///////////////////////////////////////////////////////////////////////////////////////
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// Function which fetches required number of rows
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///////////////////////////////////////////////////////////////////////////////////////
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HRESULT CInstanceRowFetchObj::FetchRows(CRowset * pRowset,
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HCHAPTER hChapter, // IN The Chapter handle.
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DBROWOFFSET lRowOffset, // IN Rows to skip before reading
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DBROWCOUNT cRows, // IN Number of rows to fetch
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DBCOUNTITEM* pcRowsObtained, // OUT Number of rows obtained
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HROW ** prghRows) // OUT Array of Hrows obtained)
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{
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DBCOUNTITEM cRowsTmp = 0;
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HROW irow(0), ih(0);
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PROWBUFF prowbuff = NULL;
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HRESULT hr = S_OK;
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HROW *prghRowsTemp = NULL;
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HROW hRowCurrent = 0;
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HSLOT hSlot = -1;
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BOOL bAlreadyDataRetrieved = FALSE;
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BOOL bAlreadyFetched = FALSE;
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CVARIANT varKey;
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BOOL bFetchBack = FALSE;
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HROW hRowTemp = 0;
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CBSTR strKey;
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LONG_PTR lFetchPos = 0;
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DBROWCOUNT ulMax = 0;
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BOOL bMaxRowsExceed = FALSE;
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DBSTATUS dwStat = DBSTATUS_S_OK;
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BOOL bHRowsAllocated = FALSE;
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CWbemClassWrapper *pInst = NULL;
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if(cRows != 0)
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{
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{
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VARIANT varTemp;
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VariantInit(&varTemp);
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pRowset->GetRowsetProperty(DBPROP_MAXOPENROWS,varTemp);
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ulMax = varTemp.lVal;
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VariantClear(&varTemp);
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}
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//=======================================================
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// If already maximum rows are opened then return
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//=======================================================
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if( pRowset->m_ulRowRefCount >= (DBROWCOUNT)ulMax)
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{
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hr = DB_S_ROWLIMITEXCEEDED;
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}
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else
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{
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//========================
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// Fetch Data
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//========================
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if (lRowOffset)
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{
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//===================================
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// Calculate the new position
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//===================================
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hr = pRowset->ResetRowsetToNewPosition(lRowOffset,pInst);
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if( FAILED(hr))
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{
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pRowset->SetStatus(hChapter , STAT_ENDOFCURSOR);
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hr = DB_S_ENDOFROWSET ;
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}
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}
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// 07/11/00
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//141938
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if(hr == S_OK)
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{
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if(0 >( lFetchPos = GetFirstFetchPos(pRowset,cRows,lRowOffset)))
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{
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hr = DB_E_BADSTARTPOSITION;
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}
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else
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{
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cRowsTmp = cRows >= 0 ? cRows : cRows * (-1);
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ulMax = ulMax - pRowset->m_ulRowRefCount;
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if(ulMax < (DBROWCOUNT)cRowsTmp)
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{
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bMaxRowsExceed = TRUE;
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}
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else
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{
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ulMax = cRowsTmp;
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}
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cRowsTmp = 0;
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//=======================================================================
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// If any rows is to be retrieved then allocate memory for the HROWS
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//=======================================================================
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if (ulMax )
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{
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try
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{
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prghRowsTemp = (HROW *) g_pIMalloc->Alloc( ulMax * sizeof( HROW ));
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}
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catch(...)
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{
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if(prghRowsTemp != NULL)
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{
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g_pIMalloc->Free(prghRowsTemp);
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}
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throw;
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}
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}
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if(prghRowsTemp == NULL)
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{
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hr = E_OUTOFMEMORY;
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}
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else
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{
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memset(prghRowsTemp,0,ulMax * sizeof(HROW));
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pRowset->m_FetchDir = (LONG_PTR)cRows < 0 ? FETCHDIRBACKWARD : FETCHDIRFORWARD;
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bFetchBack = (LONG_PTR)cRows < 0 ? TRUE : FALSE;
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hRowTemp = pRowset->m_hRowLastFetched;
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for (irow =1; irow <= (ULONG)ulMax; irow++)
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{
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bAlreadyFetched = FALSE;
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bAlreadyDataRetrieved = FALSE;
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dwStat = DBSTATUS_S_OK;
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//============================================================
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// Get the pointer to the next instance
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//============================================================
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if (S_OK != ( hr = pRowset->GetNextInstance(pInst,strKey,bFetchBack)))
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{
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pRowset->SetStatus(hChapter , STAT_ENDOFCURSOR);
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hr = DB_S_ENDOFROWSET;
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break;
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}
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//==========================================================================
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// If the instance is a deleted instance and deleted instance is to be
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// removed then continue to the next instance
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// If the rowset is opened in dyanamic cursor mode then skipping of
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// deleted row doesn't depend on REMOVEDELETED
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//==========================================================================
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if(pRowset->IsInstanceDeleted(pInst) &&
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(pRowset->m_ulProps & OTHERINSERT) ||
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( pRowset->m_ulProps & REMOVEDELETED) )
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{
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irow--;
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continue;
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}
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//=================================================================
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// Check if instance already exist
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//=================================================================
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bAlreadyFetched = pRowset->m_InstMgr->IsInstanceExist(strKey);
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//==========================================================================
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// If not able to find the instance by key ( key might change sometime
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// in some cases if all the properties are keys) So check if the instance
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// is already fetched by the instance pointers
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//==========================================================================
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if(bAlreadyFetched == FALSE)
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{
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bAlreadyFetched = pRowset->m_InstMgr->IsInstanceExist(pInst );
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//==========================================================================
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// if found the instance has to be refreshed
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//==========================================================================
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if(bAlreadyFetched == TRUE)
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{
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pRowset->RefreshInstance(pInst);
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}
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}
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//==================================================================
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// if already exists get the HROW and slot number for the instance
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//==================================================================
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if(bAlreadyFetched == TRUE)
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{
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hRowCurrent = pRowset->m_InstMgr->GetHRow(strKey);
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if((pRowset->GetRowStatus(hRowCurrent) & DBROWSTATUS_E_DELETED) && ( pRowset->m_ulProps & REMOVEDELETED))
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{
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continue;
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}
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//=================================================================
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// if the slot number for the instance exist this means thet
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// data is already retrieved for the row
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//=================================================================
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if((hSlot = pRowset->m_InstMgr->GetSlot(hRowCurrent)) != -1)
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{
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bAlreadyDataRetrieved = TRUE;
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}
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}
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else
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{
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hRowCurrent = pRowset->GetNextHRow();
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}
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//=====================================================
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// Get the data if data is already not fetched
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//=====================================================
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if(bAlreadyDataRetrieved == FALSE)
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{
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hSlot = -1;
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//============================================
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// Get the next slot for retrieving data and
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// bind it to the column mem manager
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//============================================
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if (FAILED( hr = GetNextSlots( pRowset->m_pIBuffer, 1, &hSlot )))
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{
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break;
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}
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if (FAILED( pRowset->Rebind((BYTE *) pRowset->GetRowBuffFromSlot( hSlot, TRUE ))))
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{
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hr = E_FAIL;
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break;
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}
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hRowCurrent = hSlot;
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//=========================================================
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// fill the bookmark with keyvalue of the instance
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//=========================================================
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varKey.SetStr(strKey);
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//=================================================================================================
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// if the other updates visible property is set to false ,then get the data to the local buffer
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//=================================================================================================
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if(!( pRowset->m_ulProps & OTHERUPDATEDELETE))
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{
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if(FAILED(hr = pRowset->GetInstanceDataToLocalBuffer(pInst,hSlot)))
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{
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break;
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}
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//===========================================================================
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// if there is atleast one row retrieved and there are neseted columns
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// then allocate rows for the child recordsets
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//===========================================================================
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if(pRowset->m_cNestedCols > 0 )
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{
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if(pRowset->m_ppChildRowsets == NULL)
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{
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pRowset->AllocateAndInitializeChildRowsets();
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}
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//=====================================================================
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// Fill the HCHAPTERS for the column
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//=====================================================================
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if(FAILED(hr = pRowset->FillHChaptersForRow(pInst,strKey)))
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{
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break;
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}
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}
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}
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//=================================================
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// add instance pointer to instance manager
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//=================================================
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if(FAILED(hr = pRowset->m_InstMgr->AddInstanceToList(hRowCurrent,pInst,strKey,hSlot)))
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{
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break;
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}
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//=====================================================
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// if the row is deleted then set the row status
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//=====================================================
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if(pRowset->IsInstanceDeleted(pInst) && SUCCEEDED(hr))
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{
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pRowset->SetRowStatus(hRowCurrent,DBROWSTATUS_E_DELETED);
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}
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varKey.Clear();
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}
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prghRowsTemp[irow-1] = hSlot;
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strKey.Clear();
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strKey.Unbind();
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}
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if(SUCCEEDED(hr))
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{
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cRowsTmp = irow - 1; //Irow will be +1 because of For Loop
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//=====================================================================
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// Through fetching many rows of data
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//
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// Allocate row handles for client. Note that we need to use IMalloc
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// for this. Should only malloc cRowsTmp, instead of cRows.
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// Should malloc cRows, since client will assume it's that big.
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//=====================================================================
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if ( *prghRows == NULL && cRowsTmp )
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{
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try
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{
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*prghRows = (HROW *) g_pIMalloc->Alloc( cRowsTmp * sizeof( HROW ));
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}
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catch(...)
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{
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if(*prghRows)
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{
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g_pIMalloc->Free(*prghRows);
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}
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throw;
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}
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bHRowsAllocated = TRUE;
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}
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if ( *prghRows == NULL && cRowsTmp )
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{
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hr = E_OUTOFMEMORY ;
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}
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else
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{
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memset(*prghRows,0,cRowsTmp * sizeof( HROW ));
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//=====================================================================
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// Fill in the status information: Length, IsNull. May be able to wait
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// until first call to GetData, but have to do it sometime.
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//
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// Suggest keeping an array of structs of accessor info. One element is
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// whether accessor requires any status info or length info.
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//
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// Then we could skip this whole section.
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//
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// Added check for cRowsTmp to MarkRows call. Don't want to call if
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// cRowsTmp==0.
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// (Range passed to MarkRows is inclusive, so can't specify marking 0 rows.)
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//
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// Note that SetSlots is a CBitArray member function -- not an IBuffer function.
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//
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// Bits are [0...n-1], row handles are [1...n].
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//
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// Cleanup. Row handles, bits, indices are the same [m....(m+n)], where
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// m is some # >0,
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//
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// Added row-wise reference counts and cursor-wise reference counts.
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//
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// Set row handles, fix data length field and compute data status field.
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//=======================================================================
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pRowset->m_cRows = cRowsTmp;
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for (ih =0; ih < (ULONG) pRowset->m_cRows; ih++)
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{
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//=============================================================================
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// Increment the rows-read count,
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// then store it as the bookmark in the very first DWORD of the row.
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//=============================================================================
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prowbuff = pRowset->GetRowBuff( prghRowsTemp[ih], TRUE );
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//=======================================================================================
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// Insert the bookmark and its row number (from 1...n) into a hash table.
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// This allows us to quickly determine the presence of a row in mem, given the bookmark.
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// The bookmark is contained in the row buffer, at the very beginning.
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// Bookmark is the row number within the entire result set [1...num_rows_read].
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// This was a new Bookmark, not in memory,
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// so return to user (in *prghRows) the hRow we stored.
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//=======================================================================================
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prowbuff->ulRefCount++;
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pRowset->m_ulRowRefCount++;
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(*prghRows)[ih] = prghRowsTemp[ih]; // (HROW) ( irow );
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pRowset->m_hRowLastFetched = prghRowsTemp[ih];
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if(pRowset->m_ulProps & BOOKMARKPROP)
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{
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if(ih != 0)
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{
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lFetchPos = (pRowset->m_FetchDir == FETCHDIRFORWARD ) ? lFetchPos + 1 : lFetchPos -1;
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}
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prowbuff->dwBmk = lFetchPos;
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prowbuff->cbBmk = BOOKMARKSIZE;
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pRowset->m_lLastFetchPos = lFetchPos;
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// Add bookmark to the hashtable
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pRowset->m_pHashTblBkmark->InsertFindBmk(FALSE,prghRowsTemp[ih],prowbuff->cbBmk,(BYTE *)&(prowbuff->dwBmk),(ULONG_PTR*)&hSlot);
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}
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}
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} // If proper allocation of *prghRows if required
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} // If succeeded(hr) after the loop
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if(SUCCEEDED(hr))
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{
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*pcRowsObtained = cRowsTmp;
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}
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//=====================================================
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// if the number of rows asked is more than
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// the max number of open rows and if there
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// is no error then set the error number
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//=====================================================
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if( hr == S_OK && bMaxRowsExceed == TRUE)
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{
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hr = DB_S_ROWLIMITEXCEEDED;
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}
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} // Else for check for proper allocation prghRowsTemp
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} // Else for check for DB_E_BADSTARTPOSITION
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}
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}
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} // if cRow > 0
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// IF failed clean up
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if( FAILED(hr))
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{
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for (ih =0; ih < (ULONG) cRowsTmp; ih++)
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{
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if(prghRowsTemp[ih] != 0)
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{
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pRowset->m_InstMgr->DeleteInstanceFromList(prghRowsTemp[ih]);
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}
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}
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if(pcRowsObtained)
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{
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*pcRowsObtained = 0;
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}
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if(prghRows && bHRowsAllocated == TRUE)
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{
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g_pIMalloc->Free(prghRows);
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prghRows = NULL;
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}
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else
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if(prghRows)
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{
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*prghRows = NULL;
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}
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if(pcRowsObtained)
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{
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*pcRowsObtained = 0;
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}
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}
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//==============================================
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// free the temporary memory allocated
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//==============================================
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if(prghRowsTemp)
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{
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g_pIMalloc->Free(prghRowsTemp);
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prghRowsTemp = NULL;
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}
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// reset the starting position to the original position
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if(lRowOffset && (FAILED(hr) || (hr != S_OK && cRowsTmp == 0)))
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{
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pRowset->ResetRowsetToNewPosition(lRowOffset * (-1),pInst);
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}
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return hr;
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}
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