Leaked source code of windows server 2003
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114 lines
2.5 KiB

//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1991 - 1992.
//
// File: bitoff.hxx
//
// Contents: Index Bit Offset
//
// Classes: CBitOffset
//
// History: 10-Nov-91 BartoszM Created
//
//----------------------------------------------------------------------------
#pragma once
#define ULONG_BITS (sizeof(ULONG)*8)
#define INVALID_PAGENUM 0xFFFFFFFF
//+---------------------------------------------------------------------------
//
// Class: BitOffset
//
// Purpose: BitOffset into index
//
// Interface:
//
// History: 13-Jun-91 BartoszM Created
//
//----------------------------------------------------------------------------
struct BitOffset
{
BitOffset( BitOffset & bo ) : page( bo.page ), off( bo.off ) {}
BitOffset() : page( 0 ), off( 0 ) {}
ULONG Page() const {
return(page);
}
ULONG Offset() const {
return(off);
}
void SetPage(ULONG p) {
page = p;
}
void SetOff(ULONG offset) {
off = offset;
}
void SetInvalid() {
page = INVALID_PAGENUM;
}
BOOL Valid() const {
return( INVALID_PAGENUM != page );
}
void Init( ULONG pageNum, ULONG bitPos )
{
if (bitPos < SMARTBUF_PAGE_SIZE_IN_BITS )
{
SetPage(pageNum);
SetOff(bitPos);
}
else
{
Win4Assert ( bitPos == SMARTBUF_PAGE_SIZE_IN_BITS );
SetPage(pageNum + 1);
SetOff(0);
}
}
void operator +=( unsigned offDelta )
{
off += offDelta;
while (off >= SMARTBUF_PAGE_SIZE_IN_BITS)
{
off -= SMARTBUF_PAGE_SIZE_IN_BITS;
page++;
}
}
ULONG Delta ( const BitOffset& bitoff ) const
{
return( (page - bitoff.page) * SMARTBUF_PAGE_SIZE_IN_BITS
+ off - bitoff.off);
}
BOOL operator > ( const BitOffset & bitoff ) const
{
if ( page > bitoff.page )
{
return TRUE;
}
else if ( ( page == bitoff.page ) &&
( off > bitoff.off )
)
{
return TRUE;
}
return FALSE;
}
#ifdef CIEXTMODE
void CiExtDump(void *ciExtSelf);
#endif
private:
ULONG page; // page number
ULONG off; // bit offset within page
};