Source code of Windows XP (NT5)
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//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1992 - 1994.
//
// File: pathcomp.hxx
//
// Contents: Class definitions for doing "smart" path comparison in
// bigtable.
//
// Classes: CSplitPath, CSplitPathCompare
//
// History: 5-09-95 srikants Created
//
//----------------------------------------------------------------------------
#pragma once
#include "pathstor.hxx"
//+---------------------------------------------------------------------------
//
// Class: CSplitPath
//
// Purpose: To hold a path as consisting of two components - a parent
// component and a file component. This will be used
// for doing path comparisons without having to construct a
// full path but instead using the two components.
//
// History: 5-09-95 srikants Created
//
// Notes: It is possible to simplify the logic of comparison if we
// were to construct a full path by concatening the parent
// and file but that would require a big buffer. Allocating
// from heap for each comparison is expensive and the buffer is
// too big (MAX_PATH * sizeof(WCHAR)) to be allocated on stack.
// If stack can be used, the logic can be simplified
// significantly.
//
//----------------------------------------------------------------------------
class CSplitPath
{
enum ECompareStep { eUseParent, eUsePathSep, eUseFile, eDone };
friend class CPathStore;
public:
CSplitPath( CPathStore & pathStore, PATHID pathid );
CSplitPath( const WCHAR * path );
void Advance( ULONG cwc );
BOOL IsDone() const { return eDone == _step; }
int CompareCurr( CSplitPath & rhs )
{
ULONG cwcMin = min( _cwcCurr, rhs._cwcCurr );
if ( 0 == cwcMin )
return 0;
return _wcsnicmp( _pCurr, rhs._pCurr, cwcMin );
}
ULONG GetCurrLen() const { return _cwcCurr; }
unsigned GetStep() const { return _step; }
void FormFullPath( WCHAR * pwszPath, ULONG cwcPath ) const ;
void FormFileName( WCHAR * pwszFile, ULONG cwcFile ) const ;
ULONG GetFullPathLen() const;
ULONG GetFileNameLen() const
{
return _cwcFile+1;
}
void InitForPathCompare()
{
_pCurr = _pParent;
_cwcCurr = _cwcParent;
_step = eUseParent;
}
void InitForNameCompare()
{
if ( 0 != _pFile )
_SetUseFile();
else
_SetDone();
}
private:
//
// Parent part of the path.
//
const WCHAR * _pParent;
ULONG _cwcParent;
//
// File part of the path.
//
const WCHAR * _pFile;
ULONG _cwcFile;
//
// Used for comparing two split paths.
//
const WCHAR * _pCurr;
ULONG _cwcCurr;
ECompareStep _step;
static const WCHAR _awszPathSep[];
void _SetUsePathSep()
{
_pCurr = _awszPathSep;
_cwcCurr = 1;
_step = eUsePathSep;
}
void _SetUseFile()
{
Win4Assert( 0 != _pFile );
_pCurr = _pFile;
_cwcCurr = _cwcFile;
_step = eUseFile;
}
void _SetDone()
{
_pCurr = 0;
_cwcCurr = 0;
_step = eDone;
}
};
//+---------------------------------------------------------------------------
//
// Class: CSplitPathCompare
//
// Purpose: To compare two paths which are "Split".
//
// History: 5-09-95 srikants Created
//
// Notes:
//
//----------------------------------------------------------------------------
class CSplitPathCompare
{
public:
CSplitPathCompare( CSplitPath & lhs, CSplitPath & rhs )
: _lhs(lhs), _rhs(rhs) { }
int ComparePaths();
int CompareNames();
private:
CSplitPath & _lhs;
CSplitPath & _rhs;
BOOL _IsDone() const { return _lhs.IsDone() || _rhs.IsDone(); }
int _Compare();
};