147 lines
3.3 KiB
C++
147 lines
3.3 KiB
C++
//+---------------------------------------------------------------------------
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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: bktrow.hxx
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//
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// Contents:
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//
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// Classes:
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//
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// Functions:
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//
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// History: 2-15-95 srikants Created
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//
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//----------------------------------------------------------------------------
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#pragma once
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#include <tblvarnt.hxx> // for CTableVariant
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//+---------------------------------------------------------------------------
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//
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// Class: CInlineVariant
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//
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// Purpose: To have a dummy field at the end of a PROPVARIANT. This will
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// help us get the correct offset for variable data in an inline
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// variant.
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//
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// History: 2-15-95 srikants Created
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//
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// Notes: In other places, it has been just assumed that the variable
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// part is immediately after the fixed part in a variant.
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//
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//----------------------------------------------------------------------------
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#pragma warning( disable : 4200 )
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class CInlineVariant : public CTableVariant
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{
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public:
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BYTE * GetVarBuffer()
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{
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return &_abVarData[0];
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}
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private:
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BYTE _abVarData[];
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};
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#pragma warning( default : 4200 )
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//+---------------------------------------------------------------------------
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//
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// Class: CBucketRow
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//
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// Purpose: A Bucket row consists of a columns that are part of the
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// sort key. Each field is stored as a fully expanded in-line
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// variant to avoid frequent memory allocations and frees.
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//
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// History: 2-15-95 srikants Created
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//
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// Notes:
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//
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//----------------------------------------------------------------------------
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class CBucketRow
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{
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enum { cThreshold = 20 };
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public:
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CBucketRow( unsigned cCols = 0 );
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~CBucketRow();
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//
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// The assignment operator can be used only when the RHS has the same
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// ordinality as the LHS.
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//
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CBucketRow & operator = ( CBucketRow & src );
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//
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// Initialize the specified column with given variant.
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//
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void Init( unsigned i, CTableVariant & src, BYTE * pbSrcBias = 0 );
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CTableVariant * Get( unsigned i, unsigned & size )
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{
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Win4Assert( i < _cCols );
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size = _acbVariants[i];
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return _apVariants[i];
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}
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//
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// Reallocates the specified variant to be atlease as big as cbData.
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//
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void ReAlloc( unsigned i, VARTYPE vt, unsigned cbData );
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//
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// Pointer to an array of variants that constitute the row.
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//
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PROPVARIANT ** GetVariants()
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{
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return (PROPVARIANT **) _apVariants.GetPointer();
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}
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//
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// Test if the spcified "vt" is for an ascii string.
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//
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static BOOL IsSTR( VARTYPE vt )
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{
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Win4Assert( 0 == ( VT_BYREF | vt ) );
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return LPSTR == vt;
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}
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//
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// Test if the specified "vt" is for a WIDE string.
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//
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static BOOL IsWSTR( VARTYPE vt )
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{
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Win4Assert( 0 == ( VT_BYREF | vt ) );
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return LPWSTR == vt;
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}
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private:
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// Number of columns in the row.
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unsigned _cCols;
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// Array of lengths of variants.
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XArray<unsigned> _acbVariants;
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// Array of variants, one for each column in the row.
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XArray<CInlineVariant *> _apVariants;
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};
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