226 lines
5.4 KiB
C++
226 lines
5.4 KiB
C++
//+---------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1992 - 1994.
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//
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// File: segmru.cxx
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//
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// Contents: Most Recently Used segments management.
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//
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// Classes: CMRUSegments
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//
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// History: 4-11-95 srikants Created
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//
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//
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// Notes : All methods in this are assumed to be under a larger
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// lock (like the bigtable lock).
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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 <segmru.hxx>
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#include <tableseg.hxx>
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//+---------------------------------------------------------------------------
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//
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// Function: CMRUSegments
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//
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// Synopsis: Destructor for the most recently used segments list.
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//
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// History: 4-11-95 srikants Created
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//
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// Notes:
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//
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//----------------------------------------------------------------------------
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CMRUSegments::~CMRUSegments()
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{
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for ( CWidSegmentMap * pEntry = _list.RemoveLast();
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0 != pEntry;
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pEntry = _list.RemoveLast() )
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{
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delete pEntry;
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}
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}
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//+---------------------------------------------------------------------------
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//
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// Function: IsSegmentInUse
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//
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// Synopsis: Tests if the given segment is currently in use or not.
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//
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// Arguments: [pSegment] - Segment to test.
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//
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// Returns: TRUE if the segment is in use. FALSE o/w
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//
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// History: 4-11-95 srikants Created
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//
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// Notes:
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//
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//----------------------------------------------------------------------------
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BOOL CMRUSegments::IsSegmentInUse( CTableSegment * pSegment )
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{
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Win4Assert( 0 != pSegment );
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for ( CFwdWidSegMapIter iter(_list); !_list.AtEnd(iter);
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_list.Advance(iter) )
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{
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if ( iter->GetWorkId() != widInvalid )
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{
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if ( iter->GetSegment() == pSegment ||
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pSegment->IsRowInSegment( iter->GetWorkId()) )
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{
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return TRUE;
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}
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}
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}
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return FALSE;
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}
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//+---------------------------------------------------------------------------
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//
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// Function: AddReplace
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//
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// Synopsis: Add/Replaces the wid/segment mapping entry in the MRU list.
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//
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// Arguments: [wid] - Workid of the new entry
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// [pSeg] - Pointer to the segment in which the wid is present.
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// If it is set to NULL, it just means that the wid
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// is going to be used but we don't know in which segment
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// it is present (during Bucket->Window conversion)
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//
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// History: 4-11-95 srikants Created
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//
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// Notes:
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//
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//----------------------------------------------------------------------------
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void CMRUSegments::AddReplace( WORKID wid, CTableSegment * pSeg )
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{
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Win4Assert( widInvalid != wid );
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//
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// Determine if the workid already exists in the list of MRU wids.
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// If so, just move it to the top of the list.
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//
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for ( CFwdWidSegMapIter iter(_list); !_list.AtEnd(iter);
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_list.Advance(iter) )
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{
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if ( wid == iter->GetWorkId() )
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{
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CWidSegmentMap * pCurrent = iter.GetEntry();
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_list.MoveToFront( pCurrent );
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pCurrent->Set( pSeg );
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return;
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}
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}
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//
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// We either need to remove an entry from the end or create a new one
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// and add
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//
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CWidSegmentMap * pEntry = 0;
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if ( _list.Count() < _nMaxEntries )
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{
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pEntry = new CWidSegmentMap( wid, pSeg );
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}
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else
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{
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//
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// Remove the last entry from the list and re-use it for
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// the new entry.
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//
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pEntry = _list.RemoveLast();
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}
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Win4Assert( 0 != pEntry );
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pEntry->Set( wid, pSeg );
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_list.Push(pEntry);
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return;
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}
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//+---------------------------------------------------------------------------
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//
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// Function: Invalidate
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//
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// Synopsis: Invalidate all cached pointers that are same as the given
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// one.
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//
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// Arguments: [pSegment] - The segment that is going to be invalid.
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//
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// History: 4-11-95 srikants Created
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//
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// Notes:
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//
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//----------------------------------------------------------------------------
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void CMRUSegments::Invalidate( const CTableSegment * const pSegment )
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{
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Win4Assert( 0 != pSegment );
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for ( CFwdWidSegMapIter iter(_list); !_list.AtEnd(iter);
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_list.Advance(iter) )
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{
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if ( iter->GetSegment() == pSegment )
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{
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iter->Set(0);
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}
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}
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}
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//+---------------------------------------------------------------------------
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//
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// Function: Remove
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//
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// Synopsis:
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//
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// Arguments: [wid] -
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//
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// Returns:
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//
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// Modifies:
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//
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// History: 5-30-95 srikants Created
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//
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// Notes:
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//
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//----------------------------------------------------------------------------
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void CMRUSegments::Remove( WORKID wid )
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{
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Win4Assert( widInvalid != wid );
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//
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// Determine if the workid already exists in the list of MRU wids.
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// If so, just move it to the top of the list.
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//
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CFwdWidSegMapIter iter(_list);
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while ( !_list.AtEnd(iter) )
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{
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CWidSegmentMap * pCurrent = iter.GetEntry();
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//
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// Because we may destroy the current node, we must skip ahead
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// before destorying it.
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//
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_list.Advance(iter);
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if ( wid == pCurrent->GetWorkId() )
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{
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_list.RemoveFromList( pCurrent );
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delete pCurrent;
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}
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}
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return;
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}
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