243 lines
6.4 KiB
C++
243 lines
6.4 KiB
C++
//+---------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1995.
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//
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// File: PCache.hxx
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//
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// Contents: Protocol for HROW cache
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//
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// Classes: PMiniRowCache
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//
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// History: 05-Jun-95 KyleP Created
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// 14-JAN-97 KrishnaN Undefined CI_INETSRV and related changes
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//
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//----------------------------------------------------------------------------
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#include <pch.cxx>
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#pragma hdrstop
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#include "pcache.hxx"
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//+---------------------------------------------------------------------------
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//
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// Member: PMiniRowCache::PMiniRowCache, public
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//
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// Synopsis: Initialize, and setup default binding
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//
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// Arguments: [Index] -- Identifier. Not used internally.
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// [pRowset] -- Rowset used to fill cache.
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// [cBindings] -- Size of [pBindings].
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// [pBindings] -- Default binding.
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// [cbMaxLen] -- Max length of data fetched via [pBindings]
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//
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// History: 05-Jun-95 KyleP Created.
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//
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//----------------------------------------------------------------------------
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PMiniRowCache::PMiniRowCache( int Index,
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IRowset * pRowset,
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unsigned cBindings,
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DBBINDING * pBindings,
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unsigned cbMaxLen )
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: _Index( Index ),
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_pRowset( pRowset ),
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_ahrow( 2 ),
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_chrow( 0 ),
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_ihrow( 0 ),
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_cbRow( cbMaxLen )
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{
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//
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// Setup buffer for current row
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//
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_pbRow = new BYTE [_cbRow];
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//
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// Setup accessor
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//
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IAccessor * pia = 0;
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SCODE sc = _pRowset->QueryInterface( IID_IAccessor, (void **)&pia );
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if (SUCCEEDED( sc ))
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{
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sc = pia->CreateAccessor( DBACCESSOR_ROWDATA,
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cBindings,
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pBindings,
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0,
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&_hacc,
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0);
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pia->Release();
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}
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if ( FAILED(sc) )
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{
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delete [] _pbRow;
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vqDebugOut(( DEB_ERROR,
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"PMiniRowCache: CreateAccessor(child %d) returned 0x%x\n",
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_Index, sc ));
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THROW( CException(sc) );
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}
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END_CONSTRUCTION( PMiniRowCache );
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}
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//+---------------------------------------------------------------------------
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//
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// Member: PMiniRowCache::~PMiniRowCache, public
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//
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// Synopsis: Destructor.
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//
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// History: 05-Jun-95 KyleP Created.
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//
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//----------------------------------------------------------------------------
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PMiniRowCache::~PMiniRowCache()
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{
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//
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// Release any rows not transferred out.
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//
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FlushCache();
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delete [] _pbRow;
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IAccessor * pia = 0;
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_pRowset->QueryInterface( IID_IAccessor, (void **)&pia );
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Win4Assert(pia && "Invalid accessor!");
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pia->ReleaseAccessor( _hacc, 0 );
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pia->Release();
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}
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//+---------------------------------------------------------------------------
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//
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// Member: PMiniRowCache::SetCacheSize, public
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//
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// Synopsis: Adjust number of cached rows.
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//
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// Arguments: [cNewRows] -- Number of rows to cache.
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//
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// History: 05-Jun-95 KyleP Created.
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//
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// Notes: This call is advisory. There are situtations where the
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// cache cannot be shrunk.
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//
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//----------------------------------------------------------------------------
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void PMiniRowCache::SetCacheSize( DBCOUNTITEM cNewRows )
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{
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Win4Assert( cNewRows > 0 );
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//
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// Only realloc if the cache size is different.
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//
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if ( cNewRows != (DBCOUNTITEM) _ahrow.Count() )
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{
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//
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// We can't realloc to a smaller size than the number of rows
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// we're currently holding. Where would we put them?
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//
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if ( cNewRows < (DBCOUNTITEM) _chrow - (DBROWCOUNT) _ihrow &&
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_ihrow < _chrow )
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{
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cNewRows = _chrow - _ihrow;
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}
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//
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// Canonicalize the empty case.
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//
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if ( _ihrow >= _chrow )
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_ihrow = _chrow = 0;
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//
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// Realloc array of HROWs.
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//
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HROW * pnew = new HROW [(unsigned) cNewRows];
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RtlCopyMemory( pnew,
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_ahrow.GetPointer() + _ihrow,
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(_chrow - _ihrow) * sizeof(HROW) );
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delete [] _ahrow.Acquire();
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_ahrow.Set( (unsigned) cNewRows, pnew );
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//
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// Adjust index
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//
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_chrow -= _ihrow;
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_ihrow = 0;
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}
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}
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//+---------------------------------------------------------------------------
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//
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// Member: PMiniRowCache::LoadData, protected
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//
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// Synopsis: Called by derived classes to load default data for a new row.
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//
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// History: 05-Jun-95 KyleP Created.
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//
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//----------------------------------------------------------------------------
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void PMiniRowCache::LoadData()
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{
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//
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// Load up data for row.
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//
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SCODE sc = _pRowset->GetData( _ahrow[(unsigned) _ihrow], _hacc, _pbRow );
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if ( FAILED(sc) )
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{
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vqDebugOut(( DEB_ERROR, "PMiniRowCache: GetData returned 0x%x\n", sc ));
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THROW( CException( E_FAIL ) );
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}
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#if CIDBG == 1
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if ( vqInfoLevel & DEB_ITRACE )
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{
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vqDebugOut(( DEB_ITRACE, "Data for %d: ", Index() ));
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for ( int i = 0; i < 40; i++ )
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{
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if ( _pbRow[i] >= ' ' && _pbRow[i] <= '~' && 0 == _pbRow[i+1] )
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{
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vqDebugOut(( DEB_ITRACE | DEB_NOCOMPNAME, "%wc", *(WCHAR UNALIGNED *)&_pbRow[i] ));
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i++;
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}
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else
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vqDebugOut(( DEB_ITRACE | DEB_NOCOMPNAME, "%02x", _pbRow[i] ));
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}
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vqDebugOut(( DEB_ITRACE | DEB_NOCOMPNAME, "\n", _pbRow[i] ));
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}
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#endif
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}
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//+---------------------------------------------------------------------------
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//
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// Member: PMiniRowCache::FlushCache, public
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//
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// Synopsis: Clear the cache.
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//
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// History: 05-Jun-95 KyleP Created.
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//
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//----------------------------------------------------------------------------
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void PMiniRowCache::FlushCache()
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{
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if ( !IsAtEnd() )
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{
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_pRowset->ReleaseRows( _chrow - _ihrow, _ahrow.GetPointer() + _ihrow, 0, 0, 0 );
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}
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_ihrow = _chrow = 0;
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}
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