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