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472 lines
12 KiB
472 lines
12 KiB
//+-------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1992 - 2000
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//
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// File: enumerator.inl
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//
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// Contents: Supports enumeration for collections of com objects
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//
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// History: 08-Mar-2000 AudriusZ Created
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//
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//--------------------------------------------------------------------------
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#ifndef ENUMERATOR_INL_INCLUDED
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#define ENUMERATOR_INL_INCLUDED
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#pragma once
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/*+-------------------------------------------------------------------------*
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*
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* CMMCNewEnumImpl<BaseClass, _Position, EnumImplementor>::get__NewEnum
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*
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* PURPOSE: Returns new enumerator for collection
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* in the array rgvar
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*
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* PARAMETERS:
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* IUnknown** ppUnk : [out] - new enumerator
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*
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* RETURNS:
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* HRESULT
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*
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*+-------------------------------------------------------------------------*/
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template <class BaseClass, class _Position, class EnumImplementor>
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STDMETHODIMP CMMCNewEnumImpl<BaseClass, _Position, EnumImplementor>::get__NewEnum(IUnknown** ppUnk)
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{
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SC sc;
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EnumImplementor *pEnumImpl = NULL; //get enum implementor
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// validate the parameter
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sc = ScCheckPointers (ppUnk);
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if (sc)
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return (sc.ToHr());
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*ppUnk = NULL;
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sc = ScGetEnumImplementor(pEnumImpl);
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if(sc)
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return (sc.ToHr());
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// typedef the enumerator
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typedef CComObject<CMMCEnumerator<EnumImplementor, _Position> > CEnumerator;
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// create an instance of the enumerator
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CEnumerator *pEnum = NULL;
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sc = CEnumerator::CreateInstance(&pEnum);
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if (sc)
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return (sc.ToHr());
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if(!pEnum)
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return ((sc = E_UNEXPECTED).ToHr());
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// create a connection between the enumerator and the tied object.
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sc = ScCreateConnection(*pEnum, *pEnumImpl);
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if(sc)
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return (sc.ToHr());
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// initialize the position using the Reset function
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sc = pEnumImpl->ScEnumReset(pEnum->m_position);
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if(sc)
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return (sc.ToHr());
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// get the IUnknown from which IEnumVARIANT can be queried
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sc = pEnum->QueryInterface (IID_IUnknown, (void**) ppUnk);
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if (sc)
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return (sc.ToHr());
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return (sc.ToHr());
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}
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/*+-------------------------------------------------------------------------*
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*
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* CMMCEnumerator<TiedObj,_Position>::Next
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*
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* PURPOSE: Returns the next celt items starting from the current position
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* in the array rgvar
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*
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* PARAMETERS:
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* unsigned long :
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* PVARIANT rgvar :
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* unsigned long : The number of elements actually fetched
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*
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* RETURNS:
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* STDMETHODIMP
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*
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*+-------------------------------------------------------------------------*/
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template<class TiedObj, class _Position>
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STDMETHODIMP CMMCEnumerator<TiedObj,_Position>::Next(unsigned long celt, PVARIANT rgvar,
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unsigned long * pceltFetched)
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{
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DECLARE_SC(sc, TEXT("CMMCEnumerator::Next"));
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CMyTiedObject *pTiedObj = NULL;
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PVARIANT pVar = rgvar;
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unsigned long celtFetched = 0;
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_Position posTemp = m_position;
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int i = 0;
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sc = ScGetTiedObject(pTiedObj);
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if(sc)
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goto Error;
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// initialize the variables.
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if(pceltFetched != NULL)
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*pceltFetched = 0;
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// initialize the array
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for(i = 0; i<celt; i++)
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VariantInit(&rgvar[i]);
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for(celtFetched = 0; celtFetched < celt; celtFetched++, pVar++)
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{
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// at this point, we have a valid position.
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IDispatchPtr spDispatch;
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// Get the next element from the tied object.
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// The returned IDispatch* _must_ have been AddRef'd for us!
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sc = pTiedObj->ScEnumNext(m_position, *(&spDispatch));
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if(sc)
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goto Error;
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if(sc == SC(S_FALSE) )
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goto Cleanup; // return just the elements so far.
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if(spDispatch == NULL)
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{
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sc = E_UNEXPECTED;
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goto Error;
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}
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// set the dispatch member of the input array to the interface returned
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V_VT (pVar) = VT_DISPATCH;
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V_DISPATCH (pVar) = spDispatch.Detach();
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}
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Cleanup:
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// return the count fetched, if the caller wants it
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if (pceltFetched != NULL)
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*pceltFetched = celtFetched;
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return sc.ToHr();
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Error:
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// clear the array.
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for (i=0; i<celt; i++)
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VariantClear(&rgvar[i]);
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//restore the position and set the count to zero.
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m_position = posTemp;
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celtFetched = 0;
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goto Cleanup;
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}
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/*+-------------------------------------------------------------------------*
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*
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* CMMCEnumerator<TiedObj,_Position>::Skip
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*
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* PURPOSE: Skips over the next celt elements in the enumeration sequence.
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*
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* PARAMETERS:
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* unsigned long :
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*
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* RETURNS:
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* STDMETHODIMP
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*
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*+-------------------------------------------------------------------------*/
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template<class TiedObj, class _Position>
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STDMETHODIMP CMMCEnumerator<TiedObj,_Position>::Skip(unsigned long celt)
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{
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DECLARE_SC(sc, TEXT("CMMCEnumerator::Skip"));
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CMyTiedObject *pTiedObj = NULL;
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sc = ScGetTiedObject(pTiedObj);
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if(sc)
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return (sc.ToHr());
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/*
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* It's too easy for implementers of ScEnumSkip to forget to
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* return S_FALSE if the count fetched is less than the count
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* requested. We'll take care of that here.
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*/
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unsigned long celtSkipped = celt + 1;
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/*
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* It's also easy for implementers of ScEnumNext to forget
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* that if the enumeration fails, the position needs to
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* remain unaffected.
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*/
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_Position posT = m_position;
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// call the tied object with the position.
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sc = pTiedObj->ScEnumSkip(celt, celtSkipped, posT);
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if (sc)
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return (sc.ToHr());
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/*
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* success, so update the enumeration position
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*/
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m_position = posT;
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/*
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* if this assert fails, the implementation of ScEnumSkip either
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* didn't initialize or didn't update celtSkipped
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*/
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ASSERT (celtSkipped <= celt);
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if (celtSkipped < celt)
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sc = S_FALSE;
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if (celtSkipped > celt)
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celtSkipped = celt; // sanity
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return sc.ToHr();
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}
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/*+-------------------------------------------------------------------------*
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*
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* CMMCEnumerator<TiedObj,_Position>::Reset
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*
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* PURPOSE: Resets the enumeration sequence to the beginning
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*
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* RETURNS:
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* STDMETHODIMP
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*
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*+-------------------------------------------------------------------------*/
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template<class TiedObj, class _Position>
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STDMETHODIMP CMMCEnumerator<TiedObj,_Position>::Reset()
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{
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DECLARE_SC(sc, TEXT("CMMCEnumerator::Reset"));
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CMyTiedObject *pTiedObj = NULL;
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sc = ScGetTiedObject(pTiedObj);
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if(sc)
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return (sc.ToHr());
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// call the tied object with the position.
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sc = pTiedObj->ScEnumReset(m_position);
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return sc.ToHr();
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}
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/*+-------------------------------------------------------------------------*
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*
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* CMMCEnumerator<TiedObj,_Position>::Clone
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*
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* PURPOSE: Creates a copy of the current state of enumeration
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*
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* PARAMETERS:
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* PPENUMVARIANT ppenum :
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*
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* RETURNS:
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* STDMETHODIMP
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*
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*+-------------------------------------------------------------------------*/
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template<class TiedObj, class _Position>
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STDMETHODIMP CMMCEnumerator<TiedObj,_Position>::Clone(PPENUMVARIANT ppenum)
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{
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DECLARE_SC(sc, TEXT("CMMCEnumerator::Clone"));
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if(!ppenum)
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{
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sc = E_INVALIDARG;
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return sc.ToHr();
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}
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CMyTiedObject *pTiedObj = NULL;
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sc = ScGetTiedObject(pTiedObj);
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if(sc)
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return (sc.ToHr());
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typedef CComObject<ThisClass> CNewComObject;
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CNewComObject *pNewComObj = NULL;
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// create an instance of the new enumerator.
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sc = CNewComObject::CreateInstance(&pNewComObj);
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if (sc)
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return (sc.ToHr());
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if(!pNewComObj)
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return ((sc = E_UNEXPECTED).ToHr());
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// at this point the new object has been created.
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// Set the position directly from the present state.
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pNewComObj->m_position = m_position;
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// connect the COM object to the tied object
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sc = ScCreateConnection(*pNewComObj, *pTiedObj);
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if(sc)
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return sc.ToHr();
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// addref the new object for the client.
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*ppenum = pNewComObj;
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(*ppenum)->AddRef();
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return sc.ToHr();
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}
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/***************************************************************************\
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*
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* CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::get_Count
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*
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* PURPOSE: Returns count of items in the collection
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*
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* RETURNS:
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* HRESULT
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*
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\***************************************************************************/
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template <class _CollectionInterface, class _ItemInterface>
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STDMETHODIMP CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::get_Count( PLONG pCount )
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{
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DECLARE_SC(sc, TEXT("CMMCArrayEnumBase::get_Count"));
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// parameter check
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sc = ScCheckPointers(pCount);
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if (sc)
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return sc.ToHr();
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// return the count
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*pCount = m_array.size();
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return sc.ToHr();
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}
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/***************************************************************************\
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*
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* CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::Item
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*
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* PURPOSE: Returns specified item from collection
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*
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* RETURNS:
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* HRESULT
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*
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\***************************************************************************/
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template <class _CollectionInterface, class _ItemInterface>
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STDMETHODIMP CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::Item( long Index, _ItemInterface ** ppItem )
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{
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DECLARE_SC(sc, TEXT("CMMCArrayEnumBase::Item"));
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// parameter check
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sc = ScCheckPointers(ppItem);
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if (sc)
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return sc.ToHr();
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// initialization
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*ppItem = NULL;
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// remember - we are 1 based!
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if (Index < 1 || Index > m_array.size())
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return (sc = E_INVALIDARG).ToHr();
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*ppItem = m_array[Index - 1];
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// recheck the pointer
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sc = ScCheckPointers(*ppItem, E_NOINTERFACE);
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if (sc)
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return sc.ToHr();
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(*ppItem)->AddRef();
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return sc.ToHr();
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}
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/***************************************************************************\
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*
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* CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::ScEnumReset
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*
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* PURPOSE: Resets position to the first item in the collection
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*
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* RETURNS:
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* HRESULT
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*
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\***************************************************************************/
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template <class _CollectionInterface, class _ItemInterface>
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::SC CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::ScEnumReset (unsigned &pos)
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{
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DECLARE_SC(sc, TEXT("CMMCArrayEnumBase::ScEnumReset"));
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pos = 0;
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return sc;
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}
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/***************************************************************************\
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*
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* CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::ScEnumNext
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*
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* PURPOSE: Returns item from the collection, advances position
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*
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* RETURNS:
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* HRESULT
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*
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\***************************************************************************/
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template <class _CollectionInterface, class _ItemInterface>
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::SC CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::ScEnumNext(unsigned &pos, PDISPATCH & pDispatch)
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{
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DECLARE_SC(sc, TEXT("CMMCArrayEnumBase::ScEnumNext"));
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// initialize;
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pDispatch = NULL;
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// check the ranges
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if (pos >= m_array.size())
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return sc = S_FALSE;
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// get element
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pDispatch = m_array[pos];
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// recheck the pointer
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sc = ScCheckPointers(pDispatch, E_NOINTERFACE);
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if (sc)
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return sc;
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pDispatch->AddRef();
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++pos;
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return sc;
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}
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/***************************************************************************\
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*
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* CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::ScEnumSkip
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*
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* PURPOSE: Skips the amount of items in enumeration
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*
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* RETURNS:
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* HRESULT
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*
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\***************************************************************************/
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template <class _CollectionInterface, class _ItemInterface>
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::SC CMMCArrayEnumBase<_CollectionInterface, _ItemInterface>::ScEnumSkip (unsigned long celt, unsigned long& celtSkipped, unsigned &pos)
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{
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DECLARE_SC(sc, TEXT("CMMCArrayEnumBase::ScEnumSkip"));
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// no skipped at start
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celtSkipped = 0;
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// check if it's a void task
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if (!celt)
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return sc;
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// are we behind the last item?
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if (pos >= m_array.size())
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return sc = S_FALSE;
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// how far can we go?
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celtSkipped = m_array.size() - pos;
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// but go no more than requested
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if (celtSkipped > celt)
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celtSkipped = celt;
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// advance
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pos += celtSkipped;
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// check if we could do as much as requested
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if (celtSkipped < celt)
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return sc = S_FALSE;
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return sc;
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}
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#endif // ENUMERATOR_INL_INCLUDED
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