76 lines
2.9 KiB
C++
76 lines
2.9 KiB
C++
//=--------------------------------------------------------------------------=
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// StdEnum.H
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//=--------------------------------------------------------------------------=
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// Copyright 1995-1997 Microsoft Corporation. All Rights Reserved.
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//
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// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
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// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
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// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
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// PARTICULAR PURPOSE.
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//=--------------------------------------------------------------------------=
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//
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// object definition for a generic enumerator object.
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//
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#ifndef _STDENUM_H_
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#include "Unknown.H"
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// to support a generic Enumerator object, we'll just define this
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// interface. it can be safely cast to any other enumerator, since all
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// they differ in is their pointer type in Next().
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//
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class IEnumGeneric: public IUnknown {
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public:
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virtual HRESULT __stdcall Next(ULONG celt, LPVOID rgelt, ULONG *pceltFetched) = 0;
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virtual HRESULT __stdcall Skip(ULONG celt) = 0;
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virtual HRESULT __stdcall Reset(void) = 0;
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virtual HRESULT __stdcall Clone(IEnumGeneric **ppenum) = 0;
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};
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//=--------------------------------------------------------------------------=
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// StandardEnum
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//=--------------------------------------------------------------------------=
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// a generic enumerator object. given a pointer to generic data, some
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// information about the elements, and a function to copy the elements,
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// we can implement a generic enumerator.
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//
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// NOTE: this class assumes that rgElements is HeapAlloc'd, and will free it
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// in it's destructor [although it IS valid for this to be NULL if there
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// are no elements to enumerate over.]
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//
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class CStandardEnum: public CUnknownObject, public IEnumGeneric {
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public:
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// IUnknown methods
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//
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DECLARE_STANDARD_UNKNOWN();
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// IEnumVariant methods
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//
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STDMETHOD(Next)(unsigned long celt, void * rgvar, unsigned long * pceltFetched);
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STDMETHOD(Skip)(unsigned long celt);
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STDMETHOD(Reset)();
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STDMETHOD(Clone)(IEnumGeneric **ppEnumOut);
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CStandardEnum(REFIID riid, int cElement, int cbElement, void *rgElements,
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void (WINAPI * pfnCopyElement)(void *, const void *, DWORD));
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~CStandardEnum();
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private:
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virtual HRESULT InternalQueryInterface(REFIID riid, void **ppvObjOut);
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IID m_iid; // type of enumerator that we are
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int m_cElements; // Total number of elements
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int m_cbElementSize; // Size of each element
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int m_iCurrent; // Current position: 0 = front, m_cElt = end
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VOID * m_rgElements; // Array of elements
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CStandardEnum *m_pEnumClonedFrom; // If we were cloned, from whom?
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void (WINAPI * m_pfnCopyElement)(void *, const void *, DWORD);
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};
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#define _STDENUM_H_
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#endif // _STDENUM_H_
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