pkienumformatetc.cpp

PGP8.0源码 请认真阅读您的文件包然后写出其具体功能

/*____________________________________________________________________________
	Copyright (C) 2002 PGP Corporation
	All rights reserved.

	PKIEnumFormatEtc.cpp - implements OLE IEnumFORMATETC for drag and drop
	to the shell.

	$Id: PKIEnumFormatEtc.cpp,v 1.2 2002/08/06 20:09:46 dallen Exp $
____________________________________________________________________________*/
#include "pgpPFLConfig.h"

// system header files
#include <windows.h>

// project header files
#include "PKIEnumFormatEtc.h"


//	________________________________________
//
//	IUnknown Methods

STDMETHODIMP CEnumFormatEtc::QueryInterface (
		REFIID			iid,
		void FAR* FAR*	ppv)
{
    if ((iid == IID_IUnknown) || (iid == IID_IDataObject))
	{
      *ppv = this;
      ++m_refs;
      return NOERROR;
    }
    *ppv = NULL;

    return E_NOINTERFACE;
}


STDMETHODIMP_(ULONG) CEnumFormatEtc::AddRef (void)
{
    return ++m_refs;
}


STDMETHODIMP_(ULONG) CEnumFormatEtc::Release (void)
{
	if(--m_refs == 0)
	{
		if (m_prgfe != NULL)
			delete [] m_prgfe;
		m_prgfe = NULL;
		delete this;
		return 0;
    }
    return m_refs;
}


//	________________________________________
//
//	CEnumFormatEtc Constructor
//		cFE             ULONG number of FORMATETCs in pFE
//		prgFE           LPFORMATETC to the array to enumerate.
//

CEnumFormatEtc::CEnumFormatEtc (
		ULONG		cFE,
		LPFORMATETC	prgFE)
{
    UINT i;

    m_refs = 1;

    m_iCur = 0;
    m_cfe = cFE;
    m_prgfe = new FORMATETC[(UINT)cFE];

    if (m_prgfe != NULL)
	{
        for (i = 0; i < cFE; i++)
            m_prgfe[i] = prgFE[i];
    }

    return;
}


//	________________________________________
//
//	CEnumFormatEtc Destructor

CEnumFormatEtc::~CEnumFormatEtc(void)
{
    if (m_prgfe != NULL)
        delete [] m_prgfe;
    return;
}


//	________________________________________
//
//	IEnumFORMATETC Methods


//	________________________________________
//
//	CEnumFormatEtc::Next
//
//	Purpose:
//		Returns the next element in the enumeration.
//
//	Parameters:
//		cFE             ULONG number of FORMATETCs to return.
//		pFE             LPFORMATETC in which to store the returned
//					    structures.
//		pulFE           ULONG * in which to return how many we
//						enumerated.
//
//	Return Value:
//		HRESULT         NOERROR if successful, S_FALSE otherwise,
//

STDMETHODIMP CEnumFormatEtc::Next (
		ULONG		cFE,
		LPFORMATETC	pFE,
		ULONG*		pulFE)
{
    ULONG               cReturn=0L;

    if (m_prgfe == NULL)
        return S_FALSE;

    if (pulFE == NULL)
	{
        if (cFE != 1L)
			return S_FALSE;
    }
    else
		*pulFE=0L;

    if ((pFE == NULL) || (m_iCur >= m_cfe))
        return S_FALSE;

    while ((m_iCur < m_cfe) && (cFE > 0))
	{
        *pFE++=m_prgfe[m_iCur++];
        cReturn++;
        cFE--;
    }

    if (pulFE != NULL)
		*pulFE=cReturn;

    return S_OK;
}


//	________________________________________
//
//	CEnumFormatEtc::Skip
//
//	Purpose:
//		Skips the next n elements in the enumeration.
//
//	Parameters:
//		cSkip           ULONG number of elements to skip.
//
//	Return Value:
//		HRESULT         NOERROR if successful, S_FALSE if we could not
//						skip the requested number.
//

STDMETHODIMP CEnumFormatEtc::Skip (ULONG cSkip)
{
    if (((m_iCur+cSkip) >= m_cfe) || (m_prgfe == NULL))
        return S_FALSE;

    m_iCur+=cSkip;
    return S_OK;
}


//	________________________________________
//
//	CEnumFormatEtc::Reset
//
//	Purpose:
//		Resets the current element index in the enumeration to zero.
//
//	Parameters:
//		None
//
//	Return Value:
//		HRESULT         NOERROR
//

STDMETHODIMP CEnumFormatEtc::Reset (void)
{
    m_iCur=0;
    return S_OK;
}


//	________________________________________
//
//	CEnumFormatEtc::Clone
//
//	Purpose:
//		Returns another IEnumFORMATETC with the same state as ourselves.
//
//	Parameters:
//		ppEnum          LPENUMFORMATETC * in which to return the
//						new object.
//
//	Return Value:
//		HRESULT         NOERROR or a general error value.
//

STDMETHODIMP CEnumFormatEtc::Clone (LPENUMFORMATETC *ppEnum)
{
    CEnumFormatEtc*     pNew;

    *ppEnum=NULL;

    //Create the clone
    pNew = new CEnumFormatEtc (m_cfe, m_prgfe);

    if (pNew == NULL)
		return E_OUTOFMEMORY;

    pNew->m_iCur = m_iCur;

    *ppEnum = pNew;
    return S_OK;
}