//------------------------------------------------------------------------------
  // File: CtlUtil.cpp
  //
  // Desc: DirectShow base classes.
  //
  // Copyright (c) Microsoft Corporation.  All rights reserved.
  //------------------------------------------------------------------------------
  
  // Base classes implementing IDispatch parsing for the basic control dual
  // interfaces. Derive from these and implement just the custom method and
  // property methods. We also implement CPosPassThru that can be used by
  // renderers and transforms to pass by IMediaPosition and IMediaSeeking
  
  include <streams.h>
  include <limits.h>
  include <seekpt.h>
  
  // 'bool' non standard reserved word
  #pragma warning(disable:4237)
  
  // --- CBaseDispatch implementation ----------
  CBaseDispatch::~CBaseDispatch()
  {
      if (m_pti) {
          m_pti->Release();
      }
  }
  
  // return 1 if we support GetTypeInfo
  
  STDMETHODIMP
  CBaseDispatch::GetTypeInfoCount(UINT * pctinfo)
  {
      CheckPointer(pctinfo,E_POINTER);
      ValidateReadWritePtr(pctinfo,sizeof(UINT *));
      *pctinfo = 1;
      return S_OK;
  }
  
  typedef HRESULT (STDAPICALLTYPE *LPLOADTYPELIB)(
                              const OLECHAR FAR *szFile,
                              ITypeLib FAR* FAR* pptlib);
  
  typedef HRESULT (STDAPICALLTYPE *LPLOADREGTYPELIB)(REFGUID rguid,
                              WORD wVerMajor,
                              WORD wVerMinor,
                              LCID lcid,
                              ITypeLib FAR* FAR* pptlib);
  
  // attempt to find our type library
  
  STDMETHODIMP
  CBaseDispatch::GetTypeInfo(
    REFIID riid,
    UINT itinfo,
    LCID lcid,
    ITypeInfo ** pptinfo)
  {
      CheckPointer(pptinfo,E_POINTER);
      ValidateReadWritePtr(pptinfo,sizeof(ITypeInfo *));
      HRESULT hr;
  
      *pptinfo = NULL;
  
      // we only support one type element
      if (0 != itinfo) {
          return TYPE_E_ELEMENTNOTFOUND;
      }
  
      if (NULL == pptinfo) {
          return E_POINTER;
      }
  
      // always look for neutral
      if (NULL == m_pti) {
  
          LPLOADTYPELIB            lpfnLoadTypeLib;
          LPLOADREGTYPELIB    lpfnLoadRegTypeLib;
          ITypeLib            *ptlib;
          HINSTANCE            hInst;
  
          static const char  szTypeLib[]          = "LoadTypeLib";
          static const char  szRegTypeLib[] = "LoadRegTypeLib";
          static const WCHAR szControl[]          = L"control.tlb";
  
          //
          // Try to get the Ole32Aut.dll module handle.
          //
  
          hInst = LoadOLEAut32();
          if (hInst == NULL) {
              DWORD dwError = GetLastError();
              return AmHresultFromWin32(dwError);
          }
          lpfnLoadRegTypeLib = (LPLOADREGTYPELIB)GetProcAddress(hInst,
                                                                szRegTypeLib);
          if (lpfnLoadRegTypeLib == NULL) {
              DWORD dwError = GetLastError();
              return AmHresultFromWin32(dwError);
          }
  
          hr = (*lpfnLoadRegTypeLib)(LIBID_QuartzTypeLib, 1, 0, // version 1.0
                                     lcid, &ptlib);
  
          if (FAILED(hr)) {
  
              // attempt to load directly - this will fill the
              // registry in if it finds it
  
              lpfnLoadTypeLib = (LPLOADTYPELIB)GetProcAddress(hInst, szTypeLib);
              if (lpfnLoadTypeLib == NULL) {
                  DWORD dwError = GetLastError();
                  return AmHresultFromWin32(dwError);
              }
  
              hr = (*lpfnLoadTypeLib)(szControl, &ptlib);
              if (FAILED(hr)) {
                  return hr;
              }
          }
  
          hr = ptlib->GetTypeInfoOfGuid(
                      riid,
                      &m_pti);
  
          ptlib->Release();
  
          if (FAILED(hr)) {
              return hr;
          }
      }
  
      *pptinfo = m_pti;
      m_pti->AddRef();
      return S_OK;
  }
  
  STDMETHODIMP
  CBaseDispatch::GetIDsOfNames(
    REFIID riid,
    OLECHAR  ** rgszNames,
    UINT cNames,
    LCID lcid,
    DISPID * rgdispid)
  {
      // although the IDispatch riid is dead, we use this to pass from
      // the interface implementation class to us the iid we are talking about.
  
      ITypeInfo * pti;
      HRESULT hr = GetTypeInfo(riid, 0, lcid, &pti);
  
      if (SUCCEEDED(hr)) {
          hr = pti->GetIDsOfNames(rgszNames, cNames, rgdispid);
  
          pti->Release();
      }
      return hr;
  }
  
  // --- CMediaControl implementation ---------
  
  CMediaControl::CMediaControl(const TCHAR * name,LPUNKNOWN pUnk) :
      CUnknown(name, pUnk)
  {
  }
  
  // expose our interfaces IMediaControl and IUnknown
  
  STDMETHODIMP
  CMediaControl::NonDelegatingQueryInterface(REFIID riid, void **ppv)
  {
      ValidateReadWritePtr(ppv,sizeof(PVOID));
      if (riid == IID_IMediaControl) {
          return GetInterface( (IMediaControl *) this, ppv);
      } else {
          return CUnknown::NonDelegatingQueryInterface(riid, ppv);
      }
  }
  
  // return 1 if we support GetTypeInfo
  
  STDMETHODIMP
  CMediaControl::GetTypeInfoCount(UINT * pctinfo)
  {
      return m_basedisp.GetTypeInfoCount(pctinfo);
  }
  
  // attempt to find our type library
  
  STDMETHODIMP
  CMediaControl::GetTypeInfo(
    UINT itinfo,
    LCID lcid,
    ITypeInfo ** pptinfo)
  {
      return m_basedisp.GetTypeInfo(
                  IID_IMediaControl,
                  itinfo,
                  lcid,
                  pptinfo);
  }
  
  STDMETHODIMP
  CMediaControl::GetIDsOfNames(
    REFIID riid,
    OLECHAR  ** rgszNames,
    UINT cNames,
    LCID lcid,
    DISPID * rgdispid)
  {
      return m_basedisp.GetIDsOfNames(
                          IID_IMediaControl,
                          rgszNames,
                          cNames,
                          lcid,
                          rgdispid);
  }
  
  STDMETHODIMP
  CMediaControl::Invoke(
    DISPID dispidMember,
    REFIID riid,
    LCID lcid,
    WORD wFlags,
    DISPPARAMS * pdispparams,
    VARIANT * pvarResult,
    EXCEPINFO * pexcepinfo,
    UINT * puArgErr)
  {
      // this parameter is a dead leftover from an earlier interface
      if (IID_NULL != riid) {
          return DISP_E_UNKNOWNINTERFACE;
      }
  
      ITypeInfo * pti;
      HRESULT hr = GetTypeInfo(0, lcid, &pti);
  
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pti->Invoke(
              (IMediaControl *)this,
              dispidMember,
              wFlags,
              pdispparams,
              pvarResult,
              pexcepinfo,
              puArgErr);
  
      pti->Release();
      return hr;
  }
  
  // --- CMediaEvent implementation ----------
  
  CMediaEvent::CMediaEvent(const TCHAR * name,LPUNKNOWN pUnk) :
      CUnknown(name, pUnk)
  {
  }
  
  // expose our interfaces IMediaEvent and IUnknown
  
  STDMETHODIMP
  CMediaEvent::NonDelegatingQueryInterface(REFIID riid, void **ppv)
  {
      ValidateReadWritePtr(ppv,sizeof(PVOID));
      if (riid == IID_IMediaEvent || riid == IID_IMediaEventEx) {
          return GetInterface( (IMediaEventEx *) this, ppv);
      } else {
          return CUnknown::NonDelegatingQueryInterface(riid, ppv);
      }
  }
  
  // return 1 if we support GetTypeInfo
  
  STDMETHODIMP
  CMediaEvent::GetTypeInfoCount(UINT * pctinfo)
  {
      return m_basedisp.GetTypeInfoCount(pctinfo);
  }
  
  // attempt to find our type library
  
  STDMETHODIMP
  CMediaEvent::GetTypeInfo(
    UINT itinfo,
    LCID lcid,
    ITypeInfo ** pptinfo)
  {
      return m_basedisp.GetTypeInfo(
                  IID_IMediaEvent,
                  itinfo,
                  lcid,
                  pptinfo);
  }
  
  STDMETHODIMP
  CMediaEvent::GetIDsOfNames(
    REFIID riid,
    OLECHAR  ** rgszNames,
    UINT cNames,
    LCID lcid,
    DISPID * rgdispid)
  {
      return m_basedisp.GetIDsOfNames(
                          IID_IMediaEvent,
                          rgszNames,
                          cNames,
                          lcid,
                          rgdispid);
  }
  
  STDMETHODIMP
  CMediaEvent::Invoke(
    DISPID dispidMember,
    REFIID riid,
    LCID lcid,
    WORD wFlags,
    DISPPARAMS * pdispparams,
    VARIANT * pvarResult,
    EXCEPINFO * pexcepinfo,
    UINT * puArgErr)
  {
      // this parameter is a dead leftover from an earlier interface
      if (IID_NULL != riid) {
          return DISP_E_UNKNOWNINTERFACE;
      }
  
      ITypeInfo * pti;
      HRESULT hr = GetTypeInfo(0, lcid, &pti);
  
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pti->Invoke(
              (IMediaEvent *)this,
              dispidMember,
              wFlags,
              pdispparams,
              pvarResult,
              pexcepinfo,
              puArgErr);
  
      pti->Release();
      return hr;
  }
  
  // --- CMediaPosition implementation ----------
  
  CMediaPosition::CMediaPosition(const TCHAR * name,LPUNKNOWN pUnk) :
      CUnknown(name, pUnk)
  {
  }
  
  CMediaPosition::CMediaPosition(const TCHAR * name,
                                 LPUNKNOWN pUnk,
                                 HRESULT * phr) :
      CUnknown(name, pUnk)
  {
      UNREFERENCED_PARAMETER(phr);
  }
  
  // expose our interfaces IMediaPosition and IUnknown
  
  STDMETHODIMP
  CMediaPosition::NonDelegatingQueryInterface(REFIID riid, void **ppv)
  {
      ValidateReadWritePtr(ppv,sizeof(PVOID));
      if (riid == IID_IMediaPosition) {
          return GetInterface( (IMediaPosition *) this, ppv);
      } else {
          return CUnknown::NonDelegatingQueryInterface(riid, ppv);
      }
  }
  
  // return 1 if we support GetTypeInfo
  
  STDMETHODIMP
  CMediaPosition::GetTypeInfoCount(UINT * pctinfo)
  {
      return m_basedisp.GetTypeInfoCount(pctinfo);
  }
  
  // attempt to find our type library
  
  STDMETHODIMP
  CMediaPosition::GetTypeInfo(
    UINT itinfo,
    LCID lcid,
    ITypeInfo ** pptinfo)
  {
      return m_basedisp.GetTypeInfo(
                  IID_IMediaPosition,
                  itinfo,
                  lcid,
                  pptinfo);
  }
  
  STDMETHODIMP
  CMediaPosition::GetIDsOfNames(
    REFIID riid,
    OLECHAR  ** rgszNames,
    UINT cNames,
    LCID lcid,
    DISPID * rgdispid)
  {
      return m_basedisp.GetIDsOfNames(
                          IID_IMediaPosition,
                          rgszNames,
                          cNames,
                          lcid,
                          rgdispid);
  }
  
  STDMETHODIMP
  CMediaPosition::Invoke(
    DISPID dispidMember,
    REFIID riid,
    LCID lcid,
    WORD wFlags,
    DISPPARAMS * pdispparams,
    VARIANT * pvarResult,
    EXCEPINFO * pexcepinfo,
    UINT * puArgErr)
  {
      // this parameter is a dead leftover from an earlier interface
      if (IID_NULL != riid) {
          return DISP_E_UNKNOWNINTERFACE;
      }
  
      ITypeInfo * pti;
      HRESULT hr = GetTypeInfo(0, lcid, &pti);
  
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pti->Invoke(
              (IMediaPosition *)this,
              dispidMember,
              wFlags,
              pdispparams,
              pvarResult,
              pexcepinfo,
              puArgErr);
  
      pti->Release();
      return hr;
  }
  
  // --- IMediaPosition and IMediaSeeking pass through class ----------
  
  CPosPassThru::CPosPassThru(const TCHAR *pName,
                             LPUNKNOWN pUnk,
                             HRESULT *phr,
                             IPin *pPin) :
      CMediaPosition(pName,pUnk),
      m_pPin(pPin)
  {
      if (pPin == NULL) {
  	*phr = E_POINTER;
          return;
      }
  }
  
  // Expose our IMediaSeeking and IMediaPosition interfaces
  
  STDMETHODIMP
  CPosPassThru::NonDelegatingQueryInterface(REFIID riid,void **ppv)
  {
      CheckPointer(ppv,E_POINTER);
      *ppv = NULL;
  
      if (riid == IID_IMediaSeeking) {
          return GetInterface( static_cast<IMediaSeeking *>(this), ppv);
      }
      return CMediaPosition::NonDelegatingQueryInterface(riid,ppv);
  }
  
  // Return the IMediaPosition interface from our peer
  
  HRESULT
  CPosPassThru::GetPeer(IMediaPosition ** ppMP)
  {
      *ppMP = NULL;
  
      IPin *pConnected;
      HRESULT hr = m_pPin->ConnectedTo(&pConnected);
      if (FAILED(hr)) {
          return E_NOTIMPL;
      }
      IMediaPosition * pMP;
      hr = pConnected->QueryInterface(IID_IMediaPosition, (void **) &pMP);
      pConnected->Release();
      if (FAILED(hr)) {
          return E_NOTIMPL;
      }
  
      *ppMP = pMP;
      return S_OK;
  }
  
  // Return the IMediaSeeking interface from our peer
  
  HRESULT
  CPosPassThru::GetPeerSeeking(IMediaSeeking ** ppMS)
  {
      *ppMS = NULL;
  
      IPin *pConnected;
      HRESULT hr = m_pPin->ConnectedTo(&pConnected);
      if (FAILED(hr)) {
          return E_NOTIMPL;
      }
      IMediaSeeking * pMS;
      hr = pConnected->QueryInterface(IID_IMediaSeeking, (void **) &pMS);
      pConnected->Release();
      if (FAILED(hr)) {
          return E_NOTIMPL;
      }
  
      *ppMS = pMS;
      return S_OK;
  }
  
  // --- IMediaSeeking methods ----------
  
  STDMETHODIMP
  CPosPassThru::GetCapabilities(DWORD * pCaps)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->GetCapabilities(pCaps);
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::CheckCapabilities(DWORD * pCaps)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->CheckCapabilities(pCaps);
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::IsFormatSupported(const GUID * pFormat)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->IsFormatSupported(pFormat);
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::QueryPreferredFormat(GUID *pFormat)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->QueryPreferredFormat(pFormat);
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::SetTimeFormat(const GUID * pFormat)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->SetTimeFormat(pFormat);
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::GetTimeFormat(GUID *pFormat)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->GetTimeFormat(pFormat);
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::IsUsingTimeFormat(const GUID * pFormat)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->IsUsingTimeFormat(pFormat);
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::ConvertTimeFormat(LONGLONG * pTarget, const GUID * pTargetFormat,
                                  LONGLONG    Source, const GUID * pSourceFormat )
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->ConvertTimeFormat(pTarget, pTargetFormat, Source, pSourceFormat );
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::SetPositions( LONGLONG * pCurrent, DWORD CurrentFlags
                            , LONGLONG * pStop, DWORD StopFlags )
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->SetPositions(pCurrent, CurrentFlags, pStop, StopFlags );
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::GetPositions(LONGLONG *pCurrent, LONGLONG * pStop)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->GetPositions(pCurrent,pStop);
      pMS->Release();
      return hr;
  }
  
  HRESULT
  CPosPassThru::GetSeekingLongLong
  ( HRESULT (__stdcall IMediaSeeking::*pMethod)( LONGLONG * )
  , LONGLONG * pll
  )
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (SUCCEEDED(hr))
      {
          hr = (pMS->*pMethod)(pll);
          pMS->Release();
      }
      return hr;
  }
  
  // If we don't have a current position then ask upstream
  
  STDMETHODIMP
  CPosPassThru::GetCurrentPosition(LONGLONG *pCurrent)
  {
      // Can we report the current position
      HRESULT hr = GetMediaTime(pCurrent,NULL);
      if (SUCCEEDED(hr)) hr = NOERROR;
      else hr = GetSeekingLongLong( &IMediaSeeking::GetCurrentPosition, pCurrent );
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::GetStopPosition(LONGLONG *pStop)
  {
      return GetSeekingLongLong( &IMediaSeeking::GetStopPosition, pStop );;
  }
  
  STDMETHODIMP
  CPosPassThru::GetDuration(LONGLONG *pDuration)
  {
      return GetSeekingLongLong( &IMediaSeeking::GetDuration, pDuration );;
  }
  
  STDMETHODIMP
  CPosPassThru::GetPreroll(LONGLONG *pllPreroll)
  {
      return GetSeekingLongLong( &IMediaSeeking::GetPreroll, pllPreroll );;
  }
  
  STDMETHODIMP
  CPosPassThru::GetAvailable( LONGLONG *pEarliest, LONGLONG *pLatest )
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMS->GetAvailable( pEarliest, pLatest );
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::GetRate(double * pdRate)
  {
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMS->GetRate(pdRate);
      pMS->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::SetRate(double dRate)
  {
      if (0.0 == dRate) {
                  return E_INVALIDARG;
      }
  
      IMediaSeeking* pMS;
      HRESULT hr = GetPeerSeeking(&pMS);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMS->SetRate(dRate);
      pMS->Release();
      return hr;
  }
  
  // --- IMediaPosition methods ----------
  
  STDMETHODIMP
  CPosPassThru::get_Duration(REFTIME * plength)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pMP->get_Duration(plength);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::get_CurrentPosition(REFTIME * pllTime)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->get_CurrentPosition(pllTime);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::put_CurrentPosition(REFTIME llTime)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->put_CurrentPosition(llTime);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::get_StopTime(REFTIME * pllTime)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->get_StopTime(pllTime);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::put_StopTime(REFTIME llTime)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->put_StopTime(llTime);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::get_PrerollTime(REFTIME * pllTime)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->get_PrerollTime(pllTime);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::put_PrerollTime(REFTIME llTime)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->put_PrerollTime(llTime);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::get_Rate(double * pdRate)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->get_Rate(pdRate);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::put_Rate(double dRate)
  {
      if (0.0 == dRate) {
                  return E_INVALIDARG;
      }
  
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->put_Rate(dRate);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::CanSeekForward(LONG *pCanSeekForward)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->CanSeekForward(pCanSeekForward);
      pMP->Release();
      return hr;
  }
  
  STDMETHODIMP
  CPosPassThru::CanSeekBackward(LONG *pCanSeekBackward)
  {
      IMediaPosition* pMP;
      HRESULT hr = GetPeer(&pMP);
      if (FAILED(hr)) {
          return hr;
      }
      hr = pMP->CanSeekBackward(pCanSeekBackward);
      pMP->Release();
      return hr;
  }
  
  // --- Implements the CRendererPosPassThru class ----------
  
  // Media times (eg current frame, field, sample etc) are passed through the
  // filtergraph in media samples. When a renderer gets a sample with media
  // times in it, it will call one of the RegisterMediaTime methods we expose
  // (one takes an IMediaSample, the other takes the media times direct). We
  // store the media times internally and return them in GetCurrentPosition.
  
  CRendererPosPassThru::CRendererPosPassThru(const TCHAR *pName,
                                             LPUNKNOWN pUnk,
                                             HRESULT *phr,
                                             IPin *pPin) :
      CPosPassThru(pName,pUnk,phr,pPin),
      m_StartMedia(0),
      m_EndMedia(0),
      m_bReset(TRUE)
  {
  }
  
  // Sets the media times the object should report
  
  HRESULT
  CRendererPosPassThru::RegisterMediaTime(IMediaSample *pMediaSample)
  {
      ASSERT(pMediaSample);
      LONGLONG StartMedia;
      LONGLONG EndMedia;
  
      CAutoLock cAutoLock(&m_PositionLock);
  
      // Get the media times from the sample
  
      HRESULT hr = pMediaSample->GetTime(&StartMedia,&EndMedia);
      if (FAILED(hr))
      {
          ASSERT(hr == VFW_E_SAMPLE_TIME_NOT_SET);
          return hr;
      }
  
      m_StartMedia = StartMedia;
      m_EndMedia = EndMedia;
      m_bReset = FALSE;
      return NOERROR;
  }
  
  // Sets the media times the object should report
  
  HRESULT
  CRendererPosPassThru::RegisterMediaTime(LONGLONG StartTime,LONGLONG EndTime)
  {
      CAutoLock cAutoLock(&m_PositionLock);
      m_StartMedia = StartTime;
      m_EndMedia = EndTime;
      m_bReset = FALSE;
      return NOERROR;
  }
  
  // Return the current media times registered in the object
  
  HRESULT
  CRendererPosPassThru::GetMediaTime(LONGLONG *pStartTime,LONGLONG *pEndTime)
  {
      ASSERT(pStartTime);
  
      CAutoLock cAutoLock(&m_PositionLock);
      if (m_bReset == TRUE) {
          return E_FAIL;
      }
  
      // We don't have to return the end time
  
      HRESULT hr = ConvertTimeFormat( pStartTime, 0, m_StartMedia, &TIME_FORMAT_MEDIA_TIME );
      if (pEndTime && SUCCEEDED(hr)) {
          hr = ConvertTimeFormat( pEndTime, 0, m_EndMedia, &TIME_FORMAT_MEDIA_TIME );
      }
      return hr;
  }
  
  // Resets the media times we hold
  
  HRESULT
  CRendererPosPassThru::ResetMediaTime()
  {
      CAutoLock cAutoLock(&m_PositionLock);
      m_StartMedia = 0;
      m_EndMedia = 0;
      m_bReset = TRUE;
      return NOERROR;
  }
  
  // Intended to be called by the owing filter during EOS processing so
  // that the media times can be adjusted to the stop time.  This ensures
  // that the GetCurrentPosition will actully get to the stop position.
  HRESULT
  CRendererPosPassThru::EOS()
  {
      HRESULT hr;
  
      if ( m_bReset == TRUE ) hr = E_FAIL;
      else
      {
          LONGLONG llStop;
          if SUCCEEDED(hr=GetStopPosition(&llStop))
          {
              CAutoLock cAutoLock(&m_PositionLock);
              m_StartMedia =
              m_EndMedia         = llStop;
          }
      }
      return hr;
  }
  
  // -- CSourceSeeking implementation ------------
  
  CSourceSeeking::CSourceSeeking(
      const TCHAR * pName,
      LPUNKNOWN pUnk,
      HRESULT* phr,
      CCritSec * pLock) :
          CUnknown(pName, pUnk),
          m_pLock(pLock),
          m_rtStart((long)0)
  {
      m_rtStop = _I64_MAX / 2;
      m_rtDuration = m_rtStop;
      m_dRateSeeking = 1.0;
  
      m_dwSeekingCaps = AM_SEEKING_CanSeekForwards
          | AM_SEEKING_CanSeekBackwards
          | AM_SEEKING_CanSeekAbsolute
          | AM_SEEKING_CanGetStopPos
          | AM_SEEKING_CanGetDuration;
  }
  
  HRESULT CSourceSeeking::NonDelegatingQueryInterface(REFIID riid, void **ppv)
  {
      if(riid == IID_IMediaSeeking) {
          CheckPointer(ppv, E_POINTER);
          return GetInterface(static_cast<IMediaSeeking *>(this), ppv);
      }
      else {
          return CUnknown::NonDelegatingQueryInterface(riid, ppv);
      }
  }
  
  HRESULT CSourceSeeking::IsFormatSupported(const GUID * pFormat)
  {
      CheckPointer(pFormat, E_POINTER);
      // only seeking in time (REFERENCE_TIME units) is supported
      return *pFormat == TIME_FORMAT_MEDIA_TIME ? S_OK : S_FALSE;
  }
  
  HRESULT CSourceSeeking::QueryPreferredFormat(GUID *pFormat)
  {
      CheckPointer(pFormat, E_POINTER);
      *pFormat = TIME_FORMAT_MEDIA_TIME;
      return S_OK;
  }
  
  HRESULT CSourceSeeking::SetTimeFormat(const GUID * pFormat)
  {
      CheckPointer(pFormat, E_POINTER);
  
      // nothing to set; just check that it's TIME_FORMAT_TIME
      return *pFormat == TIME_FORMAT_MEDIA_TIME ? S_OK : E_INVALIDARG;
  }
  
  HRESULT CSourceSeeking::IsUsingTimeFormat(const GUID * pFormat)
  {
      CheckPointer(pFormat, E_POINTER);
      return *pFormat == TIME_FORMAT_MEDIA_TIME ? S_OK : S_FALSE;
  }
  
  HRESULT CSourceSeeking::GetTimeFormat(GUID *pFormat)
  {
      CheckPointer(pFormat, E_POINTER);
      *pFormat = TIME_FORMAT_MEDIA_TIME;
      return S_OK;
  }
  
  HRESULT CSourceSeeking::GetDuration(LONGLONG *pDuration)
  {
      CheckPointer(pDuration, E_POINTER);
      CAutoLock lock(m_pLock);
      *pDuration = m_rtDuration;
      return S_OK;
  }
  
  HRESULT CSourceSeeking::GetStopPosition(LONGLONG *pStop)
  {
      CheckPointer(pStop, E_POINTER);
      CAutoLock lock(m_pLock);
      *pStop = m_rtStop;
      return S_OK;
  }
  
  HRESULT CSourceSeeking::GetCurrentPosition(LONGLONG *pCurrent)
  {
      // GetCurrentPosition is typically supported only in renderers and
      // not in source filters.
      return E_NOTIMPL;
  }
  
  HRESULT CSourceSeeking::GetCapabilities( DWORD * pCapabilities )
  {
      CheckPointer(pCapabilities, E_POINTER);
      *pCapabilities = m_dwSeekingCaps;
      return S_OK;
  }
  
  HRESULT CSourceSeeking::CheckCapabilities( DWORD * pCapabilities )
  {
      CheckPointer(pCapabilities, E_POINTER);
  
      // make sure all requested capabilities are in our mask
      return (~m_dwSeekingCaps & *pCapabilities) ? S_FALSE : S_OK;
  }
  
  HRESULT CSourceSeeking::ConvertTimeFormat( LONGLONG * pTarget, const GUID * pTargetFormat,
                             LONGLONG    Source, const GUID * pSourceFormat )
  {
      CheckPointer(pTarget, E_POINTER);
      // format guids can be null to indicate current format
  
      // since we only support TIME_FORMAT_MEDIA_TIME, we don't really
      // offer any conversions.
      if(pTargetFormat == 0 || *pTargetFormat == TIME_FORMAT_MEDIA_TIME)
      {
          if(pSourceFormat == 0 || *pSourceFormat == TIME_FORMAT_MEDIA_TIME)
          {
              *pTarget = Source;
              return S_OK;
          }
      }
  
      return E_INVALIDARG;
  }
  
  HRESULT CSourceSeeking::SetPositions( LONGLONG * pCurrent,  DWORD CurrentFlags
                        , LONGLONG * pStop,  DWORD StopFlags )
  {
      DWORD StopPosBits = StopFlags & AM_SEEKING_PositioningBitsMask;
      DWORD StartPosBits = CurrentFlags & AM_SEEKING_PositioningBitsMask;
  
      if(StopFlags) {
          CheckPointer(pStop, E_POINTER);
  
          // accept only relative, incremental, or absolute positioning
          if(StopPosBits != StopFlags) {
              return E_INVALIDARG;
          }
      }
  
      if(CurrentFlags) {
          CheckPointer(pCurrent, E_POINTER);
          if(StartPosBits != AM_SEEKING_AbsolutePositioning &&
             StartPosBits != AM_SEEKING_RelativePositioning) {
              return E_INVALIDARG;
          }
      }
  
      // scope for autolock
      {
          CAutoLock lock(m_pLock);
  
          // set start position
          if(StartPosBits == AM_SEEKING_AbsolutePositioning)
          {
              m_rtStart = *pCurrent;
          }
          else if(StartPosBits == AM_SEEKING_RelativePositioning)
          {
              m_rtStart += *pCurrent;
          }
  
          // set stop position
          if(StopPosBits == AM_SEEKING_AbsolutePositioning)
          {
              m_rtStop = *pStop;
          }
          else if(StopPosBits == AM_SEEKING_IncrementalPositioning)
          {
              m_rtStop = m_rtStart + *pStop;
          }
          else if(StopPosBits == AM_SEEKING_RelativePositioning)
          {
              m_rtStop = m_rtStop + *pStop;
          }
      }
  
      HRESULT hr = S_OK;
      if(SUCCEEDED(hr) && StopPosBits) {
          hr = ChangeStop();
      }
      if(StartPosBits) {
          hr = ChangeStart();
      }
  
      return hr;
  }
  
  HRESULT CSourceSeeking::GetPositions( LONGLONG * pCurrent, LONGLONG * pStop )
  {
      if(pCurrent) {
          *pCurrent = m_rtStart;
      }
      if(pStop) {
          *pStop = m_rtStop;
      }
  
      return S_OK;;
  }
  
  HRESULT CSourceSeeking::GetAvailable( LONGLONG * pEarliest, LONGLONG * pLatest )
  {
      if(pEarliest) {
          *pEarliest = 0;
      }
      if(pLatest) {
          CAutoLock lock(m_pLock);
          *pLatest = m_rtDuration;
      }
      return S_OK;
  }
  
  HRESULT CSourceSeeking::SetRate( double dRate)
  {
      {
          CAutoLock lock(m_pLock);
          m_dRateSeeking = dRate;
      }
      return ChangeRate();
  }
  
  HRESULT CSourceSeeking::GetRate( double * pdRate)
  {
      CheckPointer(pdRate, E_POINTER);
      CAutoLock lock(m_pLock);
      *pdRate = m_dRateSeeking;
      return S_OK;
  }
  
  HRESULT CSourceSeeking::GetPreroll(LONGLONG *pPreroll)
  {
      CheckPointer(pPreroll, E_POINTER);
      *pPreroll = 0;
      return S_OK;
  }
  
  // --- CSourcePosition implementation ----------
  
  CSourcePosition::CSourcePosition(const TCHAR * pName,
                                   LPUNKNOWN pUnk,
                                   HRESULT* phr,
                                   CCritSec * pLock) :
      CMediaPosition(pName, pUnk),
      m_pLock(pLock),
      m_Start(CRefTime((LONGLONG)0))
  {
      m_Stop = _I64_MAX;
      m_Rate = 1.0;
  }
  
  STDMETHODIMP
  CSourcePosition::get_Duration(REFTIME * plength)
  {
      CheckPointer(plength,E_POINTER);
      ValidateReadWritePtr(plength,sizeof(REFTIME));
      CAutoLock lock(m_pLock);
  
      *plength = m_Duration;
      return S_OK;
  }
  
  STDMETHODIMP
  CSourcePosition::put_CurrentPosition(REFTIME llTime)
  {
      m_pLock->Lock();
      m_Start = llTime;
      m_pLock->Unlock();
  
      return ChangeStart();
  }
  
  STDMETHODIMP
  CSourcePosition::get_StopTime(REFTIME * pllTime)
  {
      CheckPointer(pllTime,E_POINTER);
      ValidateReadWritePtr(pllTime,sizeof(REFTIME));
      CAutoLock lock(m_pLock);
  
      *pllTime = m_Stop;
      return S_OK;
  }
  
  STDMETHODIMP
  CSourcePosition::put_StopTime(REFTIME llTime)
  {
      m_pLock->Lock();
      m_Stop = llTime;
      m_pLock->Unlock();
  
      return ChangeStop();
  }
  
  STDMETHODIMP
  CSourcePosition::get_PrerollTime(REFTIME * pllTime)
  {
      CheckPointer(pllTime,E_POINTER);
      ValidateReadWritePtr(pllTime,sizeof(REFTIME));
      return E_NOTIMPL;
  }
  
  STDMETHODIMP
  CSourcePosition::put_PrerollTime(REFTIME llTime)
  {
      return E_NOTIMPL;
  }
  
  STDMETHODIMP
  CSourcePosition::get_Rate(double * pdRate)
  {
      CheckPointer(pdRate,E_POINTER);
      ValidateReadWritePtr(pdRate,sizeof(double));
      CAutoLock lock(m_pLock);
  
      *pdRate = m_Rate;
      return S_OK;
  }
  
  STDMETHODIMP
  CSourcePosition::put_Rate(double dRate)
  {
      m_pLock->Lock();
      m_Rate = dRate;
      m_pLock->Unlock();
  
      return ChangeRate();
  }
  
  // By default we can seek forwards
  
  STDMETHODIMP
  CSourcePosition::CanSeekForward(LONG *pCanSeekForward)
  {
      CheckPointer(pCanSeekForward,E_POINTER);
      *pCanSeekForward = OATRUE;
      return S_OK;
  }
  
  // By default we can seek backwards
  
  STDMETHODIMP
  CSourcePosition::CanSeekBackward(LONG *pCanSeekBackward)
  {
      CheckPointer(pCanSeekBackward,E_POINTER);
      *pCanSeekBackward = OATRUE;
      return S_OK;
  }
  
  // --- Implementation of CBasicAudio class ----------
  
  CBasicAudio::CBasicAudio(const TCHAR * pName,LPUNKNOWN punk) :
      CUnknown(pName, punk)
  {
  }
  
  // overriden to publicise our interfaces
  
  STDMETHODIMP
  CBasicAudio::NonDelegatingQueryInterface(REFIID riid, void **ppv)
  {
      ValidateReadWritePtr(ppv,sizeof(PVOID));
      if (riid == IID_IBasicAudio) {
          return GetInterface( (IBasicAudio *) this, ppv);
      } else {
          return CUnknown::NonDelegatingQueryInterface(riid, ppv);
      }
  }
  
  STDMETHODIMP
  CBasicAudio::GetTypeInfoCount(UINT * pctinfo)
  {
      return m_basedisp.GetTypeInfoCount(pctinfo);
  }
  
  STDMETHODIMP
  CBasicAudio::GetTypeInfo(
    UINT itinfo,
    LCID lcid,
    ITypeInfo ** pptinfo)
  {
      return m_basedisp.GetTypeInfo(
                  IID_IBasicAudio,
                  itinfo,
                  lcid,
                  pptinfo);
  }
  
  STDMETHODIMP
  CBasicAudio::GetIDsOfNames(
    REFIID riid,
    OLECHAR  ** rgszNames,
    UINT cNames,
    LCID lcid,
    DISPID * rgdispid)
  {
      return m_basedisp.GetIDsOfNames(
                          IID_IBasicAudio,
                          rgszNames,
                          cNames,
                          lcid,
                          rgdispid);
  }
  
  STDMETHODIMP
  CBasicAudio::Invoke(
    DISPID dispidMember,
    REFIID riid,
    LCID lcid,
    WORD wFlags,
    DISPPARAMS * pdispparams,
    VARIANT * pvarResult,
    EXCEPINFO * pexcepinfo,
    UINT * puArgErr)
  {
      // this parameter is a dead leftover from an earlier interface
      if (IID_NULL != riid) {
          return DISP_E_UNKNOWNINTERFACE;
      }
  
      ITypeInfo * pti;
      HRESULT hr = GetTypeInfo(0, lcid, &pti);
  
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pti->Invoke(
              (IBasicAudio *)this,
              dispidMember,
              wFlags,
              pdispparams,
              pvarResult,
              pexcepinfo,
              puArgErr);
  
      pti->Release();
      return hr;
  }
  
  // --- IVideoWindow implementation ----------
  
  CBaseVideoWindow::CBaseVideoWindow(const TCHAR * pName,LPUNKNOWN punk) :
      CUnknown(pName, punk)
  {
  }
  
  // overriden to publicise our interfaces
  
  STDMETHODIMP
  CBaseVideoWindow::NonDelegatingQueryInterface(REFIID riid, void **ppv)
  {
      ValidateReadWritePtr(ppv,sizeof(PVOID));
      if (riid == IID_IVideoWindow) {
          return GetInterface( (IVideoWindow *) this, ppv);
      } else {
          return CUnknown::NonDelegatingQueryInterface(riid, ppv);
      }
  }
  
  STDMETHODIMP
  CBaseVideoWindow::GetTypeInfoCount(UINT * pctinfo)
  {
      return m_basedisp.GetTypeInfoCount(pctinfo);
  }
  
  STDMETHODIMP
  CBaseVideoWindow::GetTypeInfo(
    UINT itinfo,
    LCID lcid,
    ITypeInfo ** pptinfo)
  {
      return m_basedisp.GetTypeInfo(
                  IID_IVideoWindow,
                  itinfo,
                  lcid,
                  pptinfo);
  }
  
  STDMETHODIMP
  CBaseVideoWindow::GetIDsOfNames(
    REFIID riid,
    OLECHAR  ** rgszNames,
    UINT cNames,
    LCID lcid,
    DISPID * rgdispid)
  {
      return m_basedisp.GetIDsOfNames(
                          IID_IVideoWindow,
                          rgszNames,
                          cNames,
                          lcid,
                          rgdispid);
  }
  
  STDMETHODIMP
  CBaseVideoWindow::Invoke(
    DISPID dispidMember,
    REFIID riid,
    LCID lcid,
    WORD wFlags,
    DISPPARAMS * pdispparams,
    VARIANT * pvarResult,
    EXCEPINFO * pexcepinfo,
    UINT * puArgErr)
  {
      // this parameter is a dead leftover from an earlier interface
      if (IID_NULL != riid) {
          return DISP_E_UNKNOWNINTERFACE;
      }
  
      ITypeInfo * pti;
      HRESULT hr = GetTypeInfo(0, lcid, &pti);
  
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pti->Invoke(
              (IVideoWindow *)this,
              dispidMember,
              wFlags,
              pdispparams,
              pvarResult,
              pexcepinfo,
              puArgErr);
  
      pti->Release();
      return hr;
  }
  
  // --- IBasicVideo implementation ----------
  
  CBaseBasicVideo::CBaseBasicVideo(const TCHAR * pName,LPUNKNOWN punk) :
      CUnknown(pName, punk)
  {
  }
  
  // overriden to publicise our interfaces
  
  STDMETHODIMP
  CBaseBasicVideo::NonDelegatingQueryInterface(REFIID riid, void **ppv)
  {
      ValidateReadWritePtr(ppv,sizeof(PVOID));
      if (riid == IID_IBasicVideo || riid == IID_IBasicVideo2) {
          return GetInterface( static_cast<IBasicVideo2 *>(this), ppv);
      } else {
          return CUnknown::NonDelegatingQueryInterface(riid, ppv);
      }
  }
  
  STDMETHODIMP
  CBaseBasicVideo::GetTypeInfoCount(UINT * pctinfo)
  {
      return m_basedisp.GetTypeInfoCount(pctinfo);
  }
  
  STDMETHODIMP
  CBaseBasicVideo::GetTypeInfo(
    UINT itinfo,
    LCID lcid,
    ITypeInfo ** pptinfo)
  {
      return m_basedisp.GetTypeInfo(
                  IID_IBasicVideo,
                  itinfo,
                  lcid,
                  pptinfo);
  }
  
  STDMETHODIMP
  CBaseBasicVideo::GetIDsOfNames(
    REFIID riid,
    OLECHAR  ** rgszNames,
    UINT cNames,
    LCID lcid,
    DISPID * rgdispid)
  {
      return m_basedisp.GetIDsOfNames(
                          IID_IBasicVideo,
                          rgszNames,
                          cNames,
                          lcid,
                          rgdispid);
  }
  
  STDMETHODIMP
  CBaseBasicVideo::Invoke(
    DISPID dispidMember,
    REFIID riid,
    LCID lcid,
    WORD wFlags,
    DISPPARAMS * pdispparams,
    VARIANT * pvarResult,
    EXCEPINFO * pexcepinfo,
    UINT * puArgErr)
  {
      // this parameter is a dead leftover from an earlier interface
      if (IID_NULL != riid) {
          return DISP_E_UNKNOWNINTERFACE;
      }
  
      ITypeInfo * pti;
      HRESULT hr = GetTypeInfo(0, lcid, &pti);
  
      if (FAILED(hr)) {
          return hr;
      }
  
      hr = pti->Invoke(
              (IBasicVideo *)this,
              dispidMember,
              wFlags,
              pdispparams,
              pvarResult,
              pexcepinfo,
              puArgErr);
  
      pti->Release();
      return hr;
  }
  
  // --- Implementation of Deferred Commands ----------
  
  CDispParams::CDispParams(UINT nArgs, VARIANT* pArgs, HRESULT *phr)
  {
     cNamedArgs = 0;
     rgdispidNamedArgs = NULL;
     cArgs = nArgs;
  
      if (cArgs) {
          rgvarg = new VARIANT[cArgs];
          if (NULL == rgvarg) {
              cArgs = 0;
              if (phr) {
                  *phr = E_OUTOFMEMORY;
              }
              return;
          }
  
          for (UINT i = 0; i < cArgs; i++) {
  
              VARIANT * pDest = &rgvarg[i];
              VARIANT * pSrc = &pArgs[i];
  
              pDest->vt = pSrc->vt;
              switch(pDest->vt) {
  
              case VT_I4:
                  pDest->lVal = pSrc->lVal;
                  break;
  
              case VT_UI1:
                  pDest->bVal = pSrc->bVal;
                  break;
  
              case VT_I2:
                  pDest->iVal = pSrc->iVal;
                  break;
  
              case VT_R4:
                  pDest->fltVal = pSrc->fltVal;
                  break;
  
              case VT_R8:
                  pDest->dblVal = pSrc->dblVal;
                  break;
  
              case VT_BOOL:
                  pDest->boolVal = pSrc->boolVal;
                  break;
  
              case VT_ERROR:
                  pDest->scode = pSrc->scode;
                  break;
  
              case VT_CY:
                  pDest->cyVal = pSrc->cyVal;
                  break;
  
              case VT_DATE:
                  pDest->date = pSrc->date;
                  break;
  
              case VT_BSTR:
                  if (pSrc->bstrVal == NULL) {
                      pDest->bstrVal = NULL;
                  } else {
  
                      // a BSTR is a WORD followed by a UNICODE string.
                      // the pointer points just after the WORD
  
                      WORD len = * (WORD*) (pSrc->bstrVal - (sizeof(WORD) / sizeof(OLECHAR)));
                      OLECHAR* pch = new OLECHAR[len + (sizeof(WORD)/sizeof(OLECHAR))];
                      if (pch) {
                          WORD *pui = (WORD*)pch;
          		*pui = len;
                           pDest->bstrVal = pch + (sizeof(WORD)/sizeof(OLECHAR));
                           CopyMemory(pDest->bstrVal, pSrc->bstrVal, len*sizeof(OLECHAR));
                      } else {
                          cArgs = i;
                          if (phr) {
                              *phr = E_OUTOFMEMORY;
                          }
                      }
                  }
                  pDest->bstrVal = pSrc->bstrVal;
                  break;
  
              case VT_UNKNOWN:
                  pDest->punkVal = pSrc->punkVal;
                  pDest->punkVal->AddRef();
                  break;
  
              case VT_DISPATCH:
                  pDest->pdispVal = pSrc->pdispVal;
                  pDest->pdispVal->AddRef();
                  break;
  
              default:
                  // a type we haven't got round to adding yet!
                  ASSERT(0);
                  break;
              }
          }
  
      } else {
          rgvarg = NULL;
      }
  
  }
  
  CDispParams::~CDispParams()
  {
      for (UINT i = 0; i < cArgs; i++) {
          switch(rgvarg[i].vt) {
          case VT_BSTR:
              if (rgvarg[i].bstrVal != NULL) {
                  OLECHAR * pch = rgvarg[i].bstrVal - (sizeof(WORD)/sizeof(OLECHAR));
                  delete pch;
              }
              break;
  
          case VT_UNKNOWN:
              rgvarg[i].punkVal->Release();
              break;
  
          case VT_DISPATCH:
              rgvarg[i].pdispVal->Release();
              break;
          }
      }
      delete[] rgvarg;
  }
  
  // lifetime is controlled by refcounts (see defer.h)
  
  CDeferredCommand::CDeferredCommand(
      CCmdQueue * pQ,
      LPUNKNOWN        pUnk,
      HRESULT *        phr,
      LPUNKNOWN        pUnkExecutor,
      REFTIME        time,
      GUID*        iid,
      long        dispidMethod,
      short        wFlags,
      long        nArgs,
      VARIANT*        pDispParams,
      VARIANT*        pvarResult,
      short*        puArgErr,
      BOOL        bStream
      ) :
          CUnknown(NAME("DeferredCommand"), pUnk),
          m_pQueue(pQ),
          m_pUnk(pUnkExecutor),
          m_iid(iid),
          m_dispidMethod(dispidMethod),
          m_wFlags(wFlags),
          m_DispParams(nArgs, pDispParams, phr),
          m_pvarResult(pvarResult),
          m_bStream(bStream),
          m_hrResult(E_ABORT)
  
  {
      // convert REFTIME to REFERENCE_TIME
      COARefTime convertor(time);
      m_time = convertor;
  
      // no check of time validity - it's ok to queue a command that's
      // already late
  
      // check iid is supportable on pUnk by QueryInterface for it
      IUnknown * pInterface;
      HRESULT hr = m_pUnk->QueryInterface(GetIID(), (void**) &pInterface);
      if (FAILED(hr)) {
  	*phr = hr;
          return;
      }
      pInterface->Release();
  
      // !!! check dispidMethod and param/return types using typelib
      ITypeInfo *pti;
      hr = m_Dispatch.GetTypeInfo(*iid, 0, 0, &pti);
      if (FAILED(hr)) {
  	*phr = hr;
          return;
      }
      // !!! some sort of ITypeInfo validity check here
      pti->Release();
  
      // Fix up the dispid for put and get
      if (wFlags == DISPATCH_PROPERTYPUT) {
          m_DispParams.cNamedArgs = 1;
          m_DispId = DISPID_PROPERTYPUT;
          m_DispParams.rgdispidNamedArgs = &m_DispId;
      }
  
      // all checks ok - add to queue
      hr = pQ->Insert(this);
      if (FAILED(hr)) {
  	*phr = hr;
      }
  }
  
  // refcounts are held by caller of InvokeAt... and by list. So if
  // we get here, we can't be on the list
  
  if 0
  CDeferredCommand::~CDeferredCommand()
  {
      // this assert is invalid since if the queue is deleted while we are
      // still on the queue, we will have been removed by the queue and this
      // m_pQueue will not have been modified.
      // ASSERT(m_pQueue == NULL);
  
      // we don't hold a ref count on pUnk, which is the object that should
      // execute the command.
      // This is because there would otherwise be a circular refcount problem
      // since pUnk probably owns the CmdQueue object that has a refcount
      // on us.
      // The lifetime of pUnk is guaranteed by it being part of, or lifetime
      // controlled by, our parent object. As long as we are on the list, pUnk
      // must be valid. Once we are off the list, we do not use pUnk.
  
  }
  endif
  
  // overriden to publicise our interfaces
  
  STDMETHODIMP
  CDeferredCommand::NonDelegatingQueryInterface(REFIID riid, void **ppv)
  {
      ValidateReadWritePtr(ppv,sizeof(PVOID));
      if (riid == IID_IDeferredCommand) {
          return GetInterface( (IDeferredCommand *) this, ppv);
      } else {
          return CUnknown::NonDelegatingQueryInterface(riid, ppv);
      }
  }
  
  // remove from q. this will reduce the refcount by one (since the q
  // holds a count) but can't make us go away since he must have a
  // refcount in order to call this method.
  
  STDMETHODIMP
  CDeferredCommand::Cancel()
  {
      if (m_pQueue == NULL) {
          return VFW_E_ALREADY_CANCELLED;
      }
  
      HRESULT hr = m_pQueue->Remove(this);
      if (FAILED(hr)) {
          return hr;
      }
  
      m_pQueue = NULL;
      return S_OK;
  }
  
  STDMETHODIMP
  CDeferredCommand::Confidence(LONG* pConfidence)
  {
      return E_NOTIMPL;
  }
  
  STDMETHODIMP
  CDeferredCommand::GetHResult(HRESULT * phrResult)
  {
      CheckPointer(phrResult,E_POINTER);
      ValidateReadWritePtr(phrResult,sizeof(HRESULT));
  
      if (m_pQueue != NULL) {
          return E_ABORT;
      }
      *phrResult = m_hrResult;
      return S_OK;
  }
  
  // set the time to be a new time (checking that it is valid) and
  // then requeue
  
  STDMETHODIMP
  CDeferredCommand::Postpone(REFTIME newtime)
  {
  
      // check that this time is not past
      // convert REFTIME to REFERENCE_TIME
      COARefTime convertor(newtime);
  
      // check that the time has not passed
      if (m_pQueue->CheckTime(convertor, IsStreamTime())) {
          return VFW_E_TIME_ALREADY_PASSED;
      }
  
      // extract from list
      HRESULT hr = m_pQueue->Remove(this);
      if (FAILED(hr)) {
          return hr;
      }
  
      // change time
      m_time = convertor;
  
      // requeue
      hr = m_pQueue->Insert(this);
  
      return hr;
  }
  
  HRESULT
  CDeferredCommand::Invoke()
  {
      // check that we are still outstanding
      if (m_pQueue == NULL) {
          return VFW_E_ALREADY_CANCELLED;
      }
  
      // get the type info
      ITypeInfo* pti;
      HRESULT hr = m_Dispatch.GetTypeInfo(GetIID(), 0, 0, &pti);
      if (FAILED(hr)) {
          return hr;
      }
  
      // qi for the expected interface and then invoke it. Note that we have to
      // treat the returned interface as IUnknown since we don't know its type.
      IUnknown* pInterface;
  
      hr = m_pUnk->QueryInterface(GetIID(), (void**) &pInterface);
      if (FAILED(hr)) {
          pti->Release();
          return hr;
      }
  
      EXCEPINFO expinfo;
      UINT uArgErr;
      m_hrResult = pti->Invoke(
          pInterface,
          GetMethod(),
          GetFlags(),
          GetParams(),
          GetResult(),
          &expinfo,
          &uArgErr);
  
      // release the interface we QI'd for
      pInterface->Release();
      pti->Release();
  
      // remove from list whether or not successful
      // or we loop indefinitely
      hr = m_pQueue->Remove(this);
      m_pQueue = NULL;
      return hr;
  }
  
  // --- CCmdQueue methods ----------
  
  CCmdQueue::CCmdQueue() :
      m_listPresentation(NAME("Presentation time command list")),
      m_listStream(NAME("Stream time command list")),
      m_evDue(TRUE),    // manual reset
      m_dwAdvise(0),
      m_pClock(NULL),
      m_bRunning(FALSE)
  {
  }
  
  CCmdQueue::~CCmdQueue()
  {
      // empty all our lists
  
      // we hold a refcount on each, so traverse and Release each
      // entry then RemoveAll to empty the list
      POSITION pos = m_listPresentation.GetHeadPosition();
  
      while(pos) {
          CDeferredCommand* pCmd = m_listPresentation.GetNext(pos);
          pCmd->Release();
      }
      m_listPresentation.RemoveAll();
  
      pos = m_listStream.GetHeadPosition();
  
      while(pos) {
          CDeferredCommand* pCmd = m_listStream.GetNext(pos);
          pCmd->Release();
      }
      m_listStream.RemoveAll();
  
      if (m_pClock) {
          if (m_dwAdvise) {
              m_pClock->Unadvise(m_dwAdvise);
              m_dwAdvise = 0;
          }
          m_pClock->Release();
      }
  }
  
  // returns a new CDeferredCommand object that will be initialised with
  // the parameters and will be added to the queue during construction.
  // returns S_OK if successfully created otherwise an error and
  // no object has been queued.
  
  HRESULT
  CCmdQueue::New(
      CDeferredCommand **ppCmd,
      LPUNKNOWN        pUnk,                // this object will execute command
      REFTIME        time,
      GUID*        iid,
      long        dispidMethod,
      short        wFlags,
      long        cArgs,
      VARIANT*        pDispParams,
      VARIANT*        pvarResult,
      short*        puArgErr,
      BOOL        bStream
  )
  {
      CAutoLock lock(&m_Lock);
  
      HRESULT hr = S_OK;
      *ppCmd = NULL;
  
      CDeferredCommand* pCmd;
      pCmd = new CDeferredCommand(
                      this,
                      NULL,            // not aggregated
                      &hr,
                      pUnk,            // this guy will execute
                      time,
                      iid,
                      dispidMethod,
                      wFlags,
                      cArgs,
                      pDispParams,
                      pvarResult,
                      puArgErr,
                      bStream);
  
      if (pCmd == NULL) {
          hr = E_OUTOFMEMORY;
      } else {
  	*ppCmd = pCmd;
      }
      return hr;
  }
  
  HRESULT
  CCmdQueue::Insert(CDeferredCommand* pCmd)
  {
      CAutoLock lock(&m_Lock);
  
      // addref the item
      pCmd->AddRef();
  
      CGenericList<CDeferredCommand> * pList;
      if (pCmd->IsStreamTime()) {
          pList = &m_listStream;
      } else {
          pList = &m_listPresentation;
      }
      POSITION pos = pList->GetHeadPosition();
  
      // seek past all items that are before us
      while (pos &&
          (pList->Get(pos)->GetTime() <= pCmd->GetTime())) {
  
          pList->GetNext(pos);
      }
  
      // now at end of list or in front of items that come later
      if (!pos) {
          pList->AddTail(pCmd);
      } else {
          pList->AddBefore(pos, pCmd);
      }
  
      SetTimeAdvise();
      return S_OK;
  }
  
  HRESULT
  CCmdQueue::Remove(CDeferredCommand* pCmd)
  {
      CAutoLock lock(&m_Lock);
      HRESULT hr = S_OK;
  
      CGenericList<CDeferredCommand> * pList;
      if (pCmd->IsStreamTime()) {
          pList = &m_listStream;
      } else {
          pList = &m_listPresentation;
      }
      POSITION pos = pList->GetHeadPosition();
  
      // traverse the list
      while (pos && (pList->Get(pos) != pCmd)) {
          pList->GetNext(pos);
      }
  
      // did we drop off the end?
      if (!pos) {
          hr = VFW_E_NOT_FOUND;
      } else {
  
          // found it - now take off list
          pList->Remove(pos);
  
          // Insert did an AddRef, so release it
          pCmd->Release();
  
          // check that timer request is still for earliest time
          SetTimeAdvise();
      }
      return hr;
  }
  
  // set the clock used for timing
  
  HRESULT
  CCmdQueue::SetSyncSource(IReferenceClock* pClock)
  {
      CAutoLock lock(&m_Lock);
  
      // addref the new clock first in case they are the same
      if (pClock) {
          pClock->AddRef();
      }
  
      // kill any advise on the old clock
      if (m_pClock) {
          if (m_dwAdvise) {
              m_pClock->Unadvise(m_dwAdvise);
              m_dwAdvise = 0;
          }
          m_pClock->Release();
      }
      m_pClock = pClock;
  
      // set up a new advise
      SetTimeAdvise();
      return S_OK;
  }
  
  // set up a timer event with the reference clock
  
  void
  CCmdQueue::SetTimeAdvise(void)
  {
      // make sure we have a clock to use
      if (!m_pClock) {
          return;
      }
  
      // reset the event whenever we are requesting a new signal
      m_evDue.Reset();
  
      // time 0 is earliest
      CRefTime current;
  
      // find the earliest presentation time
      if (m_listPresentation.GetCount() > 0) {
  
          POSITION pos = m_listPresentation.GetHeadPosition();
          current = m_listPresentation.Get(pos)->GetTime();
      }
  
      // if we're running, check the stream times too
      if (m_bRunning) {
  
          CRefTime t;
  
          if (m_listStream.GetCount() > 0) {
  
              POSITION pos = m_listStream.GetHeadPosition();
              t = m_listStream.Get(pos)->GetTime();
  
              // add on stream time offset to get presentation time
              t += m_StreamTimeOffset;
  
              // is this earlier?
              if ((current == TimeZero) || (t < current)) {
                  current = t;
              }
          }
      }
  
      // need to change?
      if ((current > TimeZero) && (current != m_tCurrentAdvise)) {
          if (m_dwAdvise) {
              m_pClock->Unadvise(m_dwAdvise);
              // reset the event whenever we are requesting a new signal
              m_evDue.Reset();
          }
  
          // ask for time advice - the first two params are either
          // stream time offset and stream time or
          // presentation time and 0. we always use the latter
          HRESULT hr = m_pClock->AdviseTime(
                      (REFERENCE_TIME)current,
                      TimeZero,
                      (HEVENT) HANDLE(m_evDue),
                      &m_dwAdvise);
  
          ASSERT(SUCCEEDED(hr));
          m_tCurrentAdvise = current;
      }
  }
  
  // switch to run mode. Streamtime to Presentation time mapping known.
  
  HRESULT
  CCmdQueue::Run(REFERENCE_TIME tStreamTimeOffset)
  {
      CAutoLock lock(&m_Lock);
  
      m_StreamTimeOffset = tStreamTimeOffset;
      m_bRunning = TRUE;
  
      // ensure advise is accurate
      SetTimeAdvise();
      return S_OK;
  }
  
  // switch to Stopped or Paused mode. Time mapping not known.
  
  HRESULT
  CCmdQueue::EndRun()
  {
      CAutoLock lock(&m_Lock);
  
      m_bRunning = FALSE;
  
      // check timer setting - stream times
      SetTimeAdvise();
      return S_OK;
  }
  
  // return a pointer to the next due command. Blocks for msTimeout
  // milliseconds until there is a due command.
  // Stream-time commands will only become due between Run and Endrun calls.
  // The command remains queued until invoked or cancelled.
  // Returns E_ABORT if timeout occurs, otherwise S_OK (or other error).
  //
  // returns an AddRef'd object
  
  HRESULT
  CCmdQueue::GetDueCommand(CDeferredCommand ** ppCmd, long msTimeout)
  {
      // loop until we timeout or find a due command
      for (;;) {
  
          {
              CAutoLock lock(&m_Lock);
  
              // find the earliest command
              CDeferredCommand * pCmd = NULL;
  
              // check the presentation time and the
              // stream time list to find the earliest
  
              if (m_listPresentation.GetCount() > 0) {
                  POSITION pos = m_listPresentation.GetHeadPosition();
                  pCmd = m_listPresentation.Get(pos);
              }
  
              if (m_bRunning && (m_listStream.GetCount() > 0)) {
                  POSITION pos = m_listStream.GetHeadPosition();
                  CDeferredCommand* pStrm = m_listStream.Get(pos);
  
                  CRefTime t = pStrm->GetTime() + m_StreamTimeOffset;
                  if (!pCmd || (t < pCmd->GetTime())) {
                      pCmd = pStrm;
                  }
              }
  
              //        if we have found one, is it due?
              if (pCmd) {
                  if (CheckTime(pCmd->GetTime(), pCmd->IsStreamTime())) {
  
                      // yes it's due - addref it
                      pCmd->AddRef();
  		    *ppCmd = pCmd;
                      return S_OK;
                  }
              }
          }
  
          // block until the advise is signalled
          if (WaitForSingleObject(m_evDue, msTimeout) != WAIT_OBJECT_0) {
              return E_ABORT;
          }
      }
  }
  
  // return a pointer to a command that will be due for a given time.
  // Pass in a stream time here. The stream time offset will be passed
  // in via the Run method.
  // Commands remain queued until invoked or cancelled.
  // This method will not block. It will report E_ABORT if there are no
  // commands due yet.
  //
  // returns an AddRef'd object
  
  HRESULT
  CCmdQueue::GetCommandDueFor(REFERENCE_TIME rtStream, CDeferredCommand**ppCmd)
  {
      CAutoLock lock(&m_Lock);
  
      CRefTime tStream(rtStream);
  
      // find the earliest stream and presentation time commands
      CDeferredCommand* pStream = NULL;
      if (m_listStream.GetCount() > 0) {
          POSITION pos = m_listStream.GetHeadPosition();
          pStream = m_listStream.Get(pos);
      }
      CDeferredCommand* pPresent = NULL;
      if (m_listPresentation.GetCount() > 0) {
          POSITION pos = m_listPresentation.GetHeadPosition();
          pPresent = m_listPresentation.Get(pos);
      }
  
      // is there a presentation time that has passed already
      if (pPresent && CheckTime(pPresent->GetTime(), FALSE)) {
          pPresent->AddRef();
  	*ppCmd = pPresent;
          return S_OK;
      }
  
      // is there a stream time command due before this stream time
      if (pStream && (pStream->GetTime() <= tStream)) {
          pPresent->AddRef();
  	*ppCmd = pStream;
          return S_OK;
      }
  
      // if we are running, we can map presentation times to
      // stream time. In this case, is there a presentation time command
      // that will be due before this stream time is presented?
      if (m_bRunning && pPresent) {
  
          // this stream time will appear at...
          tStream += m_StreamTimeOffset;
  
          // due before that?
          if (pPresent->GetTime() <= tStream) {
  	    *ppCmd = pPresent;
              return S_OK;
          }
      }
  
      // no commands due yet
      return VFW_E_NOT_FOUND;
  }