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671 lines
19 KiB
671 lines
19 KiB
//+---------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1992 - 2000.
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//
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// File: RCSTRMIT.HXX
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//
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// Contents: Persistent Recoverable Stream Iterators for fixed
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// size records.
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//
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// Classes: CRcovStrmReadIter
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// CRcovStrmWriteIter
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// CRcovStrmAppendIter
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//
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// History: 25-Jan-94 SrikantS Created.
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//
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//----------------------------------------------------------------------------
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#pragma once
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#include <rcstxact.hxx>
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//+---------------------------------------------------------------------------
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//
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// Class: CRcovStrmIter
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//
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// Purpose: Iterator for the recoverable stream class assuming fixed
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// size records are stored in the stream.
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//
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// History: 1-25-94 srikants Created
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//
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//----------------------------------------------------------------------------
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class CRcovStrmIter
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{
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public:
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inline CRcovStrmIter( CRcovStrmTrans & trans , USHORT cbRec );
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inline BOOL GetRec( void *pvRec, ULONG iRec );
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inline void GetRec( void *pvRec );
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inline ULONG GetVariableRecSize();
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inline void GetVariableRecData( void * pvRec, ULONG cbRec );
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BOOL AtEnd() const { return _trans.AtEnd(); }
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inline void Advance();
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inline void Seek( ULONG iRec );
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ULONG UserDataSize( ULONG cRec ) { return cRec * (_cbRec + _CHECKSUM_SIZE); }
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ULONG UserRecordCount( ULONG cbUserData ) { return cbUserData / (_cbRec + _CHECKSUM_SIZE); }
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static unsigned SizeofChecksum() { return _CHECKSUM_SIZE; }
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protected:
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enum { _CHECKSUM_SIZE = sizeof(ULONG) };
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inline ULONG CheckSum( void const * pvRec ) const;
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inline ULONG CheckSum( void const * pvRec, unsigned cbRec ) const;
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CRcovStrmTrans & _trans; // Transaction context
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const USHORT _cbRec; // Size of user record, sans checksum
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};
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmIter::CRcovStrmIter, public
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//
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// Synopsis: Constructor. Just squirrels away member variables.
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//
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// Arguments: [trans] -- Transaction context to iterate
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// [cbRec] -- Size of 'records' to be written.
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//
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// History: 27-May-1998 KyleP Added header
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//
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//----------------------------------------------------------------------------
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inline CRcovStrmIter::CRcovStrmIter( CRcovStrmTrans & trans , USHORT cbRec )
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: _trans( trans ),
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_cbRec(cbRec)
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{
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}
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmIter::Advance, public
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//
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// Synopsis: Moves to next record
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//
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// History: 27-May-1998 KyleP Added header
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//
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//----------------------------------------------------------------------------
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inline void CRcovStrmIter::Advance()
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{
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Win4Assert( !AtEnd() );
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_trans.Advance( _cbRec + _CHECKSUM_SIZE );
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}
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmIter::Seek, public
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//
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// Synopsis: Moves to specified record
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//
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// Arguments: [iRec] -- Record to position to.
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//
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// History: 27-May-1998 KyleP Created
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//
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//----------------------------------------------------------------------------
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inline void CRcovStrmIter::Seek( ULONG iRec )
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{
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_trans.Seek( iRec * (_cbRec + _CHECKSUM_SIZE) );
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}
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmIter::CheckSum, protected
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//
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// Synopsis: Computes checksum for record
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//
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// Arguments: [pvRec] -- Record to examine
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//
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// Returns: Checksum
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//
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// History: 27-May-1998 KyleP Created
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//
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// Notes: Checksum is never 0. This is to avoid a common failed write
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// scenario where zeros are written (or nothing is ever written)
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// to a persistent data structure.
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//
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//----------------------------------------------------------------------------
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inline ULONG CRcovStrmIter::CheckSum( void const * pvRec ) const
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{
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return CheckSum( pvRec, _cbRec );
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}
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmIter::CheckSum, protected
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//
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// Synopsis: Computes checksum for variable size records
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//
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// Arguments: [pvRec] -- Record to examine
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// [cbRec] -- Size of record
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//
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// Returns: Checksum
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//
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// History: 1-Jun-1998 VikasMan Created
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//
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// Notes: Checksum is never 0. This is to avoid a common failed write
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// scenario where zeros are written (or nothing is ever written)
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// to a persistent data structure.
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//
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//----------------------------------------------------------------------------
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inline ULONG CRcovStrmIter::CheckSum( void const * pvRec, unsigned cbRec ) const
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{
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BYTE * pb = (BYTE *)pvRec;
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ULONG ulCheckSum = 0;
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//
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// First, the DWORD granular portion
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//
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unsigned cbEnd = cbRec - _CHECKSUM_SIZE;
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for ( unsigned i = 0; i <= cbEnd; i += _CHECKSUM_SIZE )
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{
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ulCheckSum += *(ULONG UNALIGNED *)pb;
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pb += _CHECKSUM_SIZE;
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}
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//
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// Then whatever is left.
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//
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ULONG ul = 0;
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for ( ; i < cbRec; i++ )
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{
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ul = (ul << 8) + *pb;
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pb++;
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}
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ulCheckSum += ul;
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//
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// Make sure the checksum is never zero. Just to avoid an obvious case
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// of error where a whole section has been zero-ed (including checksum).
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//
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if ( 0 == ulCheckSum )
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ulCheckSum = 1;
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return ulCheckSum;
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}
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//+---------------------------------------------------------------------------
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//
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// Function: CRcovStrmIter::GetRec, public
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//
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// Synopsis: Gets the specified record.
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//
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// Effects: Positions the current pointer after the current read.
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//
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// Arguments: [pvRec] -- Buffer to read the contents into.
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// [iRec] -- Number of the record, starting at 0.
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//
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// Returns: TRUE if a record was successfully read. FALSE if iRec
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// is beyond the end of stream.
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//
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// History: 2-10-94 srikants Created
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//
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//----------------------------------------------------------------------------
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inline BOOL CRcovStrmIter::GetRec( void * pvRec , ULONG iRec )
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{
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if ( !_trans.Seek(iRec * (_cbRec + _CHECKSUM_SIZE) ) || AtEnd() ) {
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return FALSE;
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}
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ULONG cbRead = _trans.Read( pvRec, _cbRec );
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Win4Assert( cbRead == _cbRec );
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ULONG ulCheckSum;
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if ( _CHECKSUM_SIZE != _trans.Read( &ulCheckSum, sizeof(ulCheckSum) ) )
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{
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ciDebugOut(( DEB_ERROR, "Error reading checksum for record %u (cbRec = %u).\n",
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iRec, _cbRec ));
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Win4Assert( !"Bad checksum" );
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THROW( CException(CI_CORRUPT_CATALOG) );
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}
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if ( ulCheckSum != CheckSum( pvRec ) )
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{
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ciDebugOut(( DEB_ERROR,
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"Incorrect checksum 0x%x (should be 0x%x) for record %u (cbRec = %u). pvRec = 0x%x\n",
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CheckSum( pvRec ), ulCheckSum, iRec, _cbRec, pvRec ));
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Win4Assert( !"Bad checksum" );
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THROW( CException(CI_CORRUPT_CATALOG) );
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}
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return cbRead == _cbRec;
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}
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//+---------------------------------------------------------------------------
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//
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// Function: CRcovStrmIter::GetRec, public
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//
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// Synopsis: Gets the current record.
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//
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// Effects: Positions the current pointer after the current read.
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//
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// Arguments: [pvRec] -- Buffer to read the contents into.
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//
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// History: 27-May-1998 KyleP Created
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//
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//----------------------------------------------------------------------------
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inline void CRcovStrmIter::GetRec( void *pvRec )
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{
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GetVariableRecData( pvRec, _cbRec );
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}
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//+---------------------------------------------------------------------------
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//
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// Function: CRcovStrmIter::GetVariableRecSize, public
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//
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// Synopsis: Gets the size of the current variable record.
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//
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// Effects: Positions the current pointer after the current read.
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//
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// Arguments:
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//
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// Returns: The size in bytes of the records
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//
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// History: 1-Jun-1998 VikasMan Created
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//
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//----------------------------------------------------------------------------
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inline ULONG CRcovStrmIter::GetVariableRecSize()
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{
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Win4Assert( !AtEnd() );
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ULONG cbRec;
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ULONG cbRead;
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// Read Size
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cbRead = _trans.Read( &cbRec, sizeof( cbRec ) );
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Win4Assert( sizeof( cbRec ) == cbRead );
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Win4Assert( cbRec );
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return cbRec;
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}
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//+---------------------------------------------------------------------------
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//
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// Function: CRcovStrmIter::GetVariableRecData, public
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//
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// Synopsis: Gets the current variable record.
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//
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// Effects: Positions the current pointer after the current read.
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//
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// Arguments: [pvRec] -- Pointer to buffer to read the contents into.
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// [cbRec] -- Size in bytes of pvRec
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//
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//
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// History: 1-Jun-1998 VikasMan Created
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//
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//----------------------------------------------------------------------------
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inline void CRcovStrmIter::GetVariableRecData( void * pvRec, ULONG cbRec )
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{
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Win4Assert( !AtEnd() );
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ULONG cbRead = _trans.Read( pvRec, cbRec );
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Win4Assert( cbRead == cbRec );
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ULONG ulCheckSum;
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if ( _CHECKSUM_SIZE != _trans.Read( &ulCheckSum, sizeof(ulCheckSum) ) )
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{
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ciDebugOut(( DEB_ERROR, "Error reading checksum.\n" ));
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Win4Assert( !"Bad checksum" );
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THROW( CException(CI_CORRUPT_CATALOG) );
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}
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if ( ulCheckSum != CheckSum( pvRec, cbRec ) )
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{
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ciDebugOut(( DEB_ERROR,
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"Incorrect checksum 0x%x (should be 0x%x). pvRec = 0x%x\n",
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CheckSum( pvRec ), ulCheckSum, pvRec ));
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Win4Assert( !"Bad checksum" );
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THROW( CException(CI_CORRUPT_CATALOG) );
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}
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}
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#if 0 // untested unsused new function
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//+---------------------------------------------------------------------------
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//
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// Function: CRcovStrmIter::GetVariableRec, public
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//
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// Synopsis: Gets the current variable record. In the process would also
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// allocate memory for it
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//
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// Effects: Positions the current pointer after the current read.
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//
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// Arguments: [ppvRec] -- Pointer to buffer to read the contents into.
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//
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// Returns: The size in bytes of *ppvRec
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//
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// History: 1-Jun-1998 VikasMan Created
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//
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//----------------------------------------------------------------------------
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inline ULONG CRcovStrmIter::GetVariableRec( void ** ppvRec )
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{
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Win4Assert( !AtEnd() );
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*ppvRec = NULL;
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ULONG cbRec;
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// Read Size
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cbRec = GetVariableRecSize();
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// Now allocate and read data
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*ppvRec = (void*) new BYTE[cbRec];
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XPtrST<BYTE> xRec((BYTE*)*ppvRec);
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GetVariableRecData( *ppvRec, cbRec );
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xRec.Acquire();
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return cbRec;
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}
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#endif
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//+---------------------------------------------------------------------------
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//
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// Class: CRcovStrmReadIter
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//
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// Purpose: Read-only version of recoverable stream iterator.
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//
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// History: 1-25-94 srikants Created
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//
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//----------------------------------------------------------------------------
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class CRcovStrmReadIter : public CRcovStrmIter
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{
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public:
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inline CRcovStrmReadIter( CRcovStrmReadTrans &readTrans, USHORT cbRec );
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};
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmReadIter::CRcovStrmReadIter, public
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//
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// Synopsis: Constructor. Just squirrels away member variables.
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//
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// Arguments: [trans] -- Transaction context to iterate
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// [cbRec] -- Size of 'records' to be written.
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//
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// History: 27-May-1998 KyleP Added header
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//
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//----------------------------------------------------------------------------
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inline CRcovStrmReadIter::CRcovStrmReadIter( CRcovStrmReadTrans & readTrans , USHORT cbRec )
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: CRcovStrmIter( readTrans, cbRec )
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{
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_trans.Seek(0);
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}
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//+---------------------------------------------------------------------------
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//
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// Class: CRcovStrmAppendIter
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//
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// Purpose: Iterator to append fixed size records to the recoverable
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// streams. This is just an optimized case of a write iterator.
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//
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// History: 2-10-94 srikants Created
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//
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//----------------------------------------------------------------------------
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class CRcovStrmAppendIter : public CRcovStrmIter
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{
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public:
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inline CRcovStrmAppendIter( CRcovStrmAppendTrans &appendTrans, USHORT cbRec );
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inline void AppendRec( const void *pvRec );
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inline void AppendVariableRec( const void *pvRec, ULONG cbRec );
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private:
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CRcovStrmAppendTrans & _appendTrans;
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};
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmAppendIter::CRcovStrmAppendIter, public
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//
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// Synopsis: Constructor. Just squirrels away member variables.
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//
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// Arguments: [trans] -- Transaction context to iterate
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// [cbRec] -- Size of 'records' to be written.
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//
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// History: 27-May-1998 KyleP Added header
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//
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//----------------------------------------------------------------------------
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inline CRcovStrmAppendIter::CRcovStrmAppendIter( CRcovStrmAppendTrans & trans, USHORT cbRec )
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: CRcovStrmIter( trans, cbRec ),
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_appendTrans( trans )
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{
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_appendTrans.Seek( ENDOFSTRM );
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}
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmAppendIter::AppendRec, public
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//
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// Synopsis: Appends record to end of stream.
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//
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// Arguments: [pvRec] -- Record to append.
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//
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// History: 27-May-1998 KyleP Added header
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//
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//----------------------------------------------------------------------------
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inline void CRcovStrmAppendIter::AppendRec( const void *pvRec )
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{
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_appendTrans.Append( pvRec, _cbRec );
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ULONG ulCheckSum = CheckSum( pvRec );
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_appendTrans.Append( &ulCheckSum, sizeof(ulCheckSum), FALSE );
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}
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmAppendIter::AppendVariableRec, public
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//
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// Synopsis: Appends variable size record to end of stream
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//
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// Arguments: [pvRec] -- Record to append.
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// [cbRec] -- Count in bytes of pvRec
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//
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// Returns: void
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//
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// History: 01-Jun-1998 VikasMan Created
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//
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//----------------------------------------------------------------------------
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inline void CRcovStrmAppendIter::AppendVariableRec( const void *pvRec,
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ULONG cbRec )
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{
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ULONG ulCheckSum;
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Win4Assert( cbRec != 0 && pvRec != 0 );
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// first write the size
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_appendTrans.Append( &cbRec, sizeof( cbRec ), FALSE );
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// next write the data
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_appendTrans.Append( pvRec, cbRec );
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ulCheckSum = CheckSum( pvRec, cbRec );
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_appendTrans.Append( &ulCheckSum, sizeof(ulCheckSum), FALSE );
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}
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//+---------------------------------------------------------------------------
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//
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// Class: CRcovStrmWriteIter
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//
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// Purpose: Iterator for writing fixed size anywhere in the
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// recoverable stream.
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//
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// History: 2-10-94 srikants Created
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//
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//----------------------------------------------------------------------------
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class CRcovStrmWriteIter : public CRcovStrmIter
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{
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public:
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inline CRcovStrmWriteIter( CRcovStrmWriteTrans & writeTrans, USHORT cbRec );
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inline BOOL SetRec( const void *pvBuf, ULONG iRec );
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inline void SetRec( const void *pvBuf );
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inline void AppendRec( const void *pvBuf );
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#if 0 // untested unused new function
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inline void SetVariableRec( const void *pvRec,
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ULONG cbRec,
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BOOL fAppend = FALSE );
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#endif
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private:
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CRcovStrmWriteTrans & _writeTrans;
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};
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmWriteIter::CRcovStrmWriteIter, public
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//
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// Synopsis: Constructor. Just squirrels away member variables.
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//
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// Arguments: [trans] -- Transaction context to iterate
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// [cbRec] -- Size of 'records' to be written.
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//
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// History: 27-May-1998 KyleP Added header
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//
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//----------------------------------------------------------------------------
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inline CRcovStrmWriteIter::CRcovStrmWriteIter( CRcovStrmWriteTrans & writeTrans, USHORT cbRec )
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: CRcovStrmIter( writeTrans, cbRec ),
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_writeTrans(writeTrans)
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{
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}
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|
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//+---------------------------------------------------------------------------
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//
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// Method: CRcovStrmWriteIter::SetRec, public
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//
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// Synopsis: Writes specified record to stream.
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//
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// Arguments: [pvRec] -- Record data
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// [iRec] -- Location at which write should occur
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//
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// History: 27-May-1998 KyleP Added header
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//
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//----------------------------------------------------------------------------
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inline BOOL CRcovStrmWriteIter::SetRec( const void * pvRec, ULONG iRec )
|
|
{
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|
if (! _writeTrans.Seek( (_cbRec + _CHECKSUM_SIZE) * iRec ) || AtEnd() )
|
|
{
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|
return FALSE;
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|
}
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|
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|
SetRec( pvRec );
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return TRUE;
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|
}
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|
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//+---------------------------------------------------------------------------
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|
//
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|
// Method: CRcovStrmWriteIter::SetRec, public
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|
//
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|
// Synopsis: Writes specified record to current location in stream.
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|
//
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|
// Arguments: [pvRec] -- Record data
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|
//
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|
// History: 27-May-1998 KyleP Added header
|
|
//
|
|
//----------------------------------------------------------------------------
|
|
|
|
inline void CRcovStrmWriteIter::SetRec( const void * pvRec )
|
|
{
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|
_writeTrans.Write( pvRec, _cbRec );
|
|
|
|
ULONG ulCheckSum = CheckSum( pvRec );
|
|
_writeTrans.Write( &ulCheckSum, sizeof(ulCheckSum) );
|
|
}
|
|
|
|
//+---------------------------------------------------------------------------
|
|
//
|
|
// Method: CRcovStrmWriteIter::AppendRec, public
|
|
//
|
|
// Synopsis: Appends record to end of stream.
|
|
//
|
|
// Arguments: [pvRec] -- Record to append.
|
|
//
|
|
// History: 27-May-1998 KyleP Added header
|
|
//
|
|
//----------------------------------------------------------------------------
|
|
|
|
inline void CRcovStrmWriteIter::AppendRec( const void *pvRec )
|
|
{
|
|
_writeTrans.Append( pvRec, _cbRec );
|
|
|
|
ULONG ulCheckSum = CheckSum( pvRec );
|
|
_writeTrans.Write( &ulCheckSum, sizeof(ulCheckSum) );
|
|
}
|
|
|
|
|
|
#if 0 // untested unused new function
|
|
|
|
//+---------------------------------------------------------------------------
|
|
//
|
|
// Method: CRcovStrmWriteIter::SetVariableRec, public
|
|
//
|
|
// Synopsis: Writes/Appends variable size record to end of stream
|
|
//
|
|
// Arguments: [pvRec] -- Record to append.
|
|
// [cbRec] -- Count in bytes of pvRec
|
|
// [fAppend] -- If TRUE, then record is appended
|
|
//
|
|
// Returns: void
|
|
//
|
|
// History: 01-Jun-1998 VikasMan Created
|
|
//
|
|
//----------------------------------------------------------------------------
|
|
inline void CRcovStrmWriteIter::SetVariableRec( const void *pvRec,
|
|
ULONG cbRec,
|
|
BOOL fAppend /* = FALSE */ )
|
|
{
|
|
ULONG ulCheckSum;
|
|
|
|
Win4Assert( cbRec != 0 && pvRec != 0 );
|
|
|
|
// first write the size
|
|
if ( fAppend )
|
|
_writeTrans.Append( &cbRec, sizeof( cbRec ) );
|
|
else
|
|
_writeTrans.Write( &cbRec, sizeof( cbRec ) );
|
|
|
|
// next write the data
|
|
_writeTrans.Write( pvRec, cbRec );
|
|
ulCheckSum = CheckSum( pvRec, cbRec );
|
|
_writeTrans.Write( &ulCheckSum, sizeof(ulCheckSum) );
|
|
}
|
|
#endif
|
|
|