133 lines
3 KiB
C++
133 lines
3 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: varntcmp.hxx
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//
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// Contents: Variant Comparator
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//
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// Classes: CCompareVariants
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//
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// Functions:
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//
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// History: 5-01-95 srikants Created
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//
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//----------------------------------------------------------------------------
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#pragma once
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#include <compare.hxx>
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class CPathStore;
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//+---------------------------------------------------------------------------
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//
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// Class: CCompareVariants
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//
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// Purpose: A comparator for a pair of variants of the same type.
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//
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// History: 5-23-95 srikants Created
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//
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// Notes:
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//
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//----------------------------------------------------------------------------
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class CCompareVariants
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{
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enum { eSortDescend = 0x1, eSortNullFirst = 0x2 };
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public:
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CCompareVariants() : _dir(0), _vt(VT_EMPTY), _iDirMult(1), _CompareFn(0) {}
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// CCompareVariants( ULONG dir, VARENUM vt )
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CCompareVariants( ULONG dir, VARTYPE vt )
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{
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Init( dir, vt );
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}
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// void Init( ULONG dir, VARENUM vt = VT_EMPTY )
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void Init( ULONG dir, VARTYPE vt = VT_EMPTY )
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{
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_dir = dir;
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_vt = vt;
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_iDirMult = ( ( dir & eSortDescend ) != 0 ) ? -1 : 1;
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_CompareFn = CComparators::GetComparator( (VARENUM) _vt );
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}
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int Compare( const PROPVARIANT * pVarnt1, const PROPVARIANT * pVarnt2 );
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int GetDirMult() const { return _iDirMult; }
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private:
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void _UpdateCompare( VARTYPE vt );
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ULONG _dir; // direction of comparison (ascent/descend)
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int _iDirMult; // -1 for descending; +1 for ascending
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FCmp _CompareFn; // Function used to compare variants of
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// type '_vt'
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// ULONG _vt; // Type of the variant currently initialized.
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VARTYPE _vt; // Type of the variant currently initialized.
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};
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inline
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int CCompareVariants::Compare( const PROPVARIANT * pVarnt1, const PROPVARIANT * pVarnt2 )
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{
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int iComp = 0;
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Win4Assert( 0 != pVarnt1 && 0 != pVarnt2 );
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VARTYPE vt1 = pVarnt1->vt;
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VARTYPE vt2 = pVarnt2->vt;
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if ( vt1 == VT_EMPTY )
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{
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if ( vt2 == VT_EMPTY )
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iComp = 0;
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else
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iComp = (_dir & eSortNullFirst) != 0 ? -1 : 1;
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}
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else if ( vt2 == VT_EMPTY )
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{
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iComp = (_dir & eSortNullFirst) != 0 ? 1 : -1;
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}
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else
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{
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//
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// Both are non empty.
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//
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if ( vt1 != vt2 )
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{
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iComp = vt2 - vt1;
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}
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else
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{
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if ( _vt != vt1 )
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{
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_UpdateCompare( (VARTYPE) vt1 );
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}
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if ( 0 != _CompareFn )
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{
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iComp = _CompareFn( *pVarnt1, *pVarnt2 );
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}
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}
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iComp *= _iDirMult;
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}
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return iComp;
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}
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inline
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void CCompareVariants::_UpdateCompare( VARTYPE vt )
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{
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_vt = vt;
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_CompareFn = CComparators::GetComparator( (VARENUM) vt );
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}
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