221 lines
8.7 KiB
C++
221 lines
8.7 KiB
C++
//+-------------------------------------------------------------------------
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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.h
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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: 14-Oct-99 VivekJ Created (as comerror.h)
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// 08-Mar-2000 AudriusZ separated some code into enumerator.h file
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//
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//--------------------------------------------------------------------------
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#ifndef ENUMERATOR_H_INCLUDED
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#define ENUMERATOR_H_INCLUDED
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#pragma once
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/***************************************************************************\
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*
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* CLASS: CMMCNewEnumImpl<BaseClass, _Position, EnumImplementor>
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*
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* PURPOSE: Implements enumeration for collection class
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* EnumImplementor class is responsible for implementing these methods:
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* SC ScEnumNext(_Position &pos, PDISPATCH & pDispatch);
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* SC ScEnumSkip(unsigned long celt, unsigned long& celtSkipped, _Position &pos);
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* SC ScEnumReset(_Position &pos);
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*
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\***************************************************************************/
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/****** usage tips *******************************************************
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* Generally you will provide just 2 params to template - this means
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* the tied object of your base class needs to implement following methods:
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* ScEnumNext, ScEnumSkip, ScEnumReset;
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*
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* If you pass same class as the first and the third template parameter, your base class is
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* required to implement mentioned methods (not the tied object).
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* It's usefull when you want to have collection and enueration in one class.
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*
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* You also may specify any other class implementing the methods as the 3rd parameter,
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* but then the BaseClass needs to implement method 'ScGetEnumImplementor' returning
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* the instance of that class
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*
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* NOTE1: since it's template class, the BaseClass is not required to define/implement
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* ScGetTiedObject, when it implements enum methods itself.
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* NOTE2: But it always IS REQUIRED to define CMyTiedObject type to compile.
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* (this template class needs it to be anything different than the BaseClass)
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* It is suggested to typedef it as void : "typedef void CMyTiedObject;"
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* NOTE3: Make sure CMyTiedObject type is public or protected
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************************************************************************/
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template <class BaseClass, class _Position, class EnumImplementor = BaseClass::CMyTiedObject>
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class CMMCNewEnumImpl : public BaseClass
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{
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// Methods to get proper implementor for Enum methods
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// simple one when implemented by the base class
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SC ScGetEnumImplementor(BaseClass * &pObj) { pObj = this; return SC(S_OK); }
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// when implemented by the tied object (default) - also simple
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SC ScGetEnumImplementor(BaseClass::CMyTiedObject * &pObj) { return ScGetTiedObject(pObj); }
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public:
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STDMETHOD(get__NewEnum)(IUnknown** ppUnk);
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};
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/*+-------------------------------------------------------------------------*
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* class CMMCEnumerator
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*
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*
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* PURPOSE: General purpose enumerator class. Keyed to a position object,
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* which is templated.
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*
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* The following three methods need to be implemented by the tied object:
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*
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* SC ScEnumNext(_Position &pos, PDISPATCH & pDispatch); // should return the next element.
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* SC ScEnumSkip(unsigned long celt, unsigned long& celtSkipped,
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* _Position &pos);
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* SC ScEnumReset(_Position &pos);
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*
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* Cloning the enumerator is taken care of automatically.
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*
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* NOTE: The Position object must have a copy constructor and assignment
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* operator.
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*+-------------------------------------------------------------------------*/
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typedef IEnumVARIANT ** PPENUMVARIANT;
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typedef VARIANT * PVARIANT;
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template<class TiedObj, class _Position>
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class CMMCEnumerator :
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public IEnumVARIANT,
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public IMMCSupportErrorInfoImpl<&IID_IEnumVARIANT, &GUID_NULL>, // rich error handling
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public CComObjectRoot,
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public CTiedComObject<TiedObj>
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{
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typedef CMMCEnumerator<TiedObj, _Position> ThisClass;
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typedef TiedObj CMyTiedObject;
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friend TiedObj;
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public:
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BEGIN_COM_MAP(ThisClass)
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COM_INTERFACE_ENTRY(IEnumVARIANT)
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END_COM_MAP()
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DECLARE_NOT_AGGREGATABLE(ThisClass)
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// Returns the next celt items starting from the current position
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// in the array rgvar
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STDMETHODIMP Next(unsigned long celt, PVARIANT rgvar, unsigned long * pceltFetched);
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// Skips over the next celt elements in the enumeration sequence.
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STDMETHODIMP Skip(unsigned long celt);
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// Resets the enumeration sequence to the beginning
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STDMETHODIMP Reset();
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// Creates a copy of the current state of enumeration
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STDMETHODIMP Clone(PPENUMVARIANT ppenum);
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public:
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// the position object that keeps track of the present location.
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_Position m_position;
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};
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/*+-------------------------------------------------------------------------*
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* class CMMCArrayEnumBase
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*
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* PURPOSE: General purpose array enumeration base class.
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* Particularly useful when array of items to be enumerated is initially
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* available, or when com object creation is not a big penalty and there
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* is no need to postpone item creation to when they are requested.
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*
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* USAGE: typedef your enumerator as CMMCNewEnumImpl parameterized by this class
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* - or even better - create the instance of CMMCArrayEnum class.
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* Use Init method passing an array of pointers to items [first, last)
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*+-------------------------------------------------------------------------*/
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template <class _CollectionInterface, class _ItemInterface>
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class CMMCArrayEnumBase :
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public CMMCIDispatchImpl<_CollectionInterface>,
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public CTiedObject // enumerators are tied to it
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{
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protected:
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typedef void CMyTiedObject; // not tied
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public:
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BEGIN_MMC_COM_MAP(CMMCArrayEnumBase)
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END_MMC_COM_MAP()
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public:
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// Returns count of items in the collection
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STDMETHODIMP get_Count( PLONG pCount );
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// Returns specified item from collection
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STDMETHODIMP Item( long Index, _ItemInterface ** ppItem );
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// Resets position to the first item in the collection
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::SC ScEnumReset (unsigned &pos);
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// Returns item from the collection, advances position
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::SC ScEnumNext (unsigned &pos, PDISPATCH & pDispatch);
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// Skips the amount of items in enumeration
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::SC ScEnumSkip (unsigned long celt, unsigned long& celtSkipped, unsigned &pos);
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// Initializes the array with given iterators
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template<typename InIt>
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void Init(InIt first, InIt last)
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{
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m_array.clear();
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m_array.reserve(last - first);
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while(first != last)
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m_array.push_back(*first), ++first;
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}
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private:
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// data members
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std::vector< CComPtr<_ItemInterface> > m_array;
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};
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/*+-------------------------------------------------------------------------*
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* class CMMCArrayEnumBase
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*
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* PURPOSE: General purpose array enumeration class.
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* Particularly useful when array of items to be enumerated is initially
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* available, or when com object creation is not a big penalty and there
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* is no need to postpone item creation to when they are requested.
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*
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* USAGE: create the instance of CMMCArrayEnum class whenever you need an
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* enumerator for the array of objects you have.
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* Parameterized by collection type and element type;
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* For instance CMMCArrayEnum< Nodes, Node >
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* Use Init method passing an array of pointers to items [first, last)
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*
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* EXAMPLE: << skipping error checking for clarity >>
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* void GetNodes(std::vector<PNODE>& InNodes, PPNODES ppOutNodes)
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* {
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* typedef CComObject< CMMCArrayEnum<Nodes, Node> > EnumNodes;
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* EnumNodes *pNodes = NULL;
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* EnumNodes::CreateInstance(&pNodes); // create
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* pNodes->Init(InNodes.begin(), InNodes.end()); // initialize with array
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* pNodes->AddRef(); // addref for caller
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* *ppOutNodes = pNodes; // return
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* }
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*
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*+-------------------------------------------------------------------------*/
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template <class _CollT, class _ItemT>
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class CMMCArrayEnum :
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public CMMCNewEnumImpl<CMMCArrayEnumBase<_CollT, _ItemT>, unsigned, CMMCArrayEnumBase<_CollT, _ItemT> >
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{
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};
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// include inline definitions
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#include "enumerator.inl"
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#endif // ENUMERATOR_H_INCLUDED
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