143 lines
4.0 KiB
C++
143 lines
4.0 KiB
C++
//-----------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1992 - 1995
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//
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// File: caccess.cxx
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//
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// Contents: Microsoft OleDB/OleDS Data Source Object for ADSI
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//
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// Implementation of the Extended Buffer Object used for storing
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// accessor handles.
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//
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// History: 10-01-96 shanksh Created.
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//----------------------------------------------------------------------------
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#include "oleds.hxx"
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#pragma hdrstop
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// --------------------------- C E X T B U F F E R ---------------------------
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//
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// Implementation class for the Extended Buffer object.
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//-----------------------------------------------------------------------------
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// CExtBuff::CExtBuff
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//
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// @mfunc CExtBuff constructor.
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//
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// @rdesc NONE
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//-----------------------------------------------------------------------------
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CExtBuff::CExtBuff(
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void
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)
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{
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_cItem = 0;
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_cItemMax = 0;
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_rgItem = NULL;
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}
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//-----------------------------------------------------------------------------
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// CExtBuff::~CExtBuff
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//
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// @mfunc CExtBuff destructor.
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//
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// @rdesc NONE
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//-----------------------------------------------------------------------------
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CExtBuff::~CExtBuff(
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void
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)
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{
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if (_rgItem)
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FreeADsMem(_rgItem);
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}
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//-----------------------------------------------------------------------------
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// FInit::CExtBuff
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//
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// CExtBuff initialization (memory allocation for the default item
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// happens here).
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//
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// @rdesc Did the Initialization Succeed
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// @flag TRUE | Initialization succeeded
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// @flag FALSE | Initializtion failed
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//-----------------------------------------------------------------------------
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BOOL CExtBuff::FInit(
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ULONG cbItem, // size of items to store
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VOID *pvItemDefault // points to a default value to return
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// when an element asked for doesn't exist
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)
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{
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ULONG_PTR hItemDefault;
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ADsAssert(cbItem);
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ADsAssert(HIWORD(cbItem) == 0);
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_cbItem = cbItem;
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_rgItem = (BYTE *)AllocADsMem((CEXTBUFFER_DITEM*_cbItem));
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if (_rgItem == NULL)
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return FALSE;
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_cItemMax = CEXTBUFFER_DITEM;
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// It's the first insertion so hItemDefault is always 0 and consequently
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// we don't need to store it.
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if (pvItemDefault)
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return (InsertIntoExtBuffer(pvItemDefault, hItemDefault) == NOERROR);
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else
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return TRUE;
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}
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//------------------------------------------------------------------------------
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// CExtBuff::InsertIntoExtBuffer
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//
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// @mfunc Stores an item in the Extended Buffer.
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//
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// @rdesc Returns one of the following values:
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// @flag S_OK | insertion succeeded,
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// @flag E_OUTOFMEMORY | insertion failed because of memory allocation
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// failure
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//-----------------------------------------------------------------------------------
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STDMETHODIMP CExtBuff::InsertIntoExtBuffer(
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VOID *pvItem, // pointer to item to be stored
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ULONG_PTR &hItem // points to where the item handle is returned
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)
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{
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// If the buffer capacity is exhausted it needs to be reallocated. Buffer capacity
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// is increased by a fixed quantum.
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if (_cItem == _cItemMax) {
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BYTE *pbTmp;
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pbTmp = (BYTE *)ReallocADsMem(
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_rgItem,
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_cItemMax * _cbItem,
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(_cItemMax +CEXTBUFFER_DITEM)*_cbItem
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);
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if (pbTmp == NULL)
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RRETURN (E_OUTOFMEMORY);
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// Buffer capacity increased.
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_cItemMax += CEXTBUFFER_DITEM;
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_rgItem = pbTmp;
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}
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// Copy the item.
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memcpy( (_rgItem + _cItem*_cbItem), (BYTE *)pvItem, _cbItem );
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_cItem++;
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// Index of the item constitues its handle.
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hItem = _cItem -1;
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return NOERROR;
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}
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