Leaked source code of windows server 2003
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//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1994.
//
// File: KVec.hxx
//
// Contents: CKeyVector
//
// Classes: CEntryBuffer, CEntryBufferHandler
//
// History: 18-Mar-93 AmyA Created.
//
//----------------------------------------------------------------------------
#pragma once
#include <entry.hxx>
//+---------------------------------------------------------------------------
//
// Class: CKeyVector
//
// Purpose: A vector of pointers to entries stored in the entry buffer
// The vector grows backwards from the end of the buffer
//
// Notes: Instead of storing pointers we store byte offsets
// from the beginning of buffer. FixPointers converts
// them to actual pointers by adding the address
// of the base pointer.
//
// History: 12-Jun-91 BartoszM Created
// 18-Mar-93 AmyA Moved from sort.hxx
//
//----------------------------------------------------------------------------
class CKeyVector
{
public:
inline void Init ( BYTE * buf, unsigned cb );
inline void Add ( CEntry* pEntry );
inline void Sentinel( CEntry* sentinel );
inline BYTE* GetCurPos() const;
inline CEntry** GetVector() const;
inline void CalculateOffsets( unsigned count );
private:
CEntry** _ppEntry;
BYTE * _pbFirstEntry;
};
//+---------------------------------------------------------------------------
//
// Member: CKeyVector::Init, public
//
// Synopsis: Initialize cursor to point to the end of buffer
//
// Arguments: [buf] -- buffer
// [cb] -- size of buffer
//
// History: 07-Jun-91 BartoszM Created
//
//----------------------------------------------------------------------------
inline void CKeyVector::Init ( BYTE * buf, unsigned cb )
{
//
// point it at the end of buffer.
// it will grow up
//
_ppEntry = (CEntry **) & buf[cb];
_pbFirstEntry = buf;
}
inline void CKeyVector::Add ( CEntry* pEntry )
{
--_ppEntry;
// store pointer to entry
*_ppEntry = pEntry;
}
inline void CKeyVector::Sentinel( CEntry* sentinel )
{
Add ( sentinel );
}
inline BYTE * CKeyVector::GetCurPos() const
{
return (BYTE*)_ppEntry;
}
inline CEntry** CKeyVector::GetVector() const
{
return _ppEntry;
}
//+---------------------------------------------------------------------------
//
// Member: CKeyVector::CalculateOffsets, public
//
// Synopsis: Calculate relative pointers by subtracting the base pointer
//
// Arguments: [count] -- number of offsets to calculate
//
// History: 30-Jun-93 AmyA Created
//
//----------------------------------------------------------------------------
inline void CKeyVector::CalculateOffsets ( unsigned count )
{
// _ppEntry stores an array of pointers to entries. We subtract the base
// pointer from all of them in order to create an array of relative
// pointers to entries.
for ( unsigned i = 0; i < count; i++ )
*((INT_PTR *)(_ppEntry+i)) = (BYTE *)(_ppEntry[i]) - _pbFirstEntry;
}