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