windows-server-2003/multimedia/published/dxmdev/dshowdev/base/sysclock.cpp

//------------------------------------------------------------------------------
// File: SysClock.cpp
//
// Desc: DirectShow base classes - implements a system clock based on 
//       IReferenceClock.
//
// Copyright (c) 1992-2001 Microsoft Corporation.  All rights reserved.
//------------------------------------------------------------------------------


#include <streams.h>
#include <limits.h>


#ifdef FILTER_DLL

/* List of class IDs and creator functions for the class factory. This
   provides the link between the OLE entry point in the DLL and an object
   being created. The class factory will call the static CreateInstance
   function when it is asked to create a CLSID_SystemClock object */

CFactoryTemplate g_Templates[1] = {
    {&CLSID_SystemClock, CSystemClock::CreateInstance}
};

int g_cTemplates = sizeof(g_Templates) / sizeof(g_Templates[0]);
#endif

/* This goes in the factory template table to create new instances */
CUnknown * WINAPI CSystemClock::CreateInstance(LPUNKNOWN pUnk,HRESULT *phr)
{
    return new CSystemClock(NAME("System reference clock"),pUnk, phr);
}


CSystemClock::CSystemClock(TCHAR *pName,LPUNKNOWN pUnk,HRESULT *phr) :
    CBaseReferenceClock(pName, pUnk, phr)
{
}

STDMETHODIMP CSystemClock::NonDelegatingQueryInterface(
    REFIID riid,
    void ** ppv)
{
    if (riid == IID_IPersist)
    {
        return GetInterface(static_cast<IPersist *>(this), ppv);
    }
    else if (riid == IID_IAMClockAdjust)
    {
        return GetInterface(static_cast<IAMClockAdjust *>(this), ppv);
    }
    else
    {
        return CBaseReferenceClock::NonDelegatingQueryInterface(riid, ppv);
    }
}

/* Return the clock's clsid */
STDMETHODIMP
CSystemClock::GetClassID(CLSID *pClsID)
{
    CheckPointer(pClsID,E_POINTER);
    ValidateReadWritePtr(pClsID,sizeof(CLSID));
    *pClsID = CLSID_SystemClock;
    return NOERROR;
}


STDMETHODIMP 
CSystemClock::SetClockDelta(REFERENCE_TIME rtDelta)
{
    return SetTimeDelta(rtDelta);
}