The Net: Ultimate Internet Guide/WWLCD1.ISO/mac/SiteBldr/AMOVIE/SDK/_SETUP/COMMON.Z/transip.h

C/C++ Source or Header | 1996-05-10 | 7.0 KB | 210 lines

//==========================================================================;
//
//  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
//  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
//  PURPOSE.
//
//  Copyright (c) 1992 - 1996  Microsoft Corporation.  All Rights Reserved.
//
//--------------------------------------------------------------------------;

//
// base class from which you can derive a simple Transform-In-Place filter.
// The difference between this and Transfrm.h is that Transfrm copies the data.
//
// It assumes the filter has one input and one output stream, and has no
// interest in memory management, interface negotiation or anything else.
//
// Derive your class from this, and supply Transform and the media type/format
// negotiation functions. Implement that class, compile and link and
// you're done.


#ifndef __TRANSIP__
#define __TRANSIP__

// ======================================================================
// This is the com object that represents a simple transform filter. It
// supports IFilter, IMediaFilter and two pins through nested interfaces
// ======================================================================

class CTransInPlaceFilter;

// Several of the pin functions call filter functions to do the work,
// so you can often use the pin classes unaltered, just overriding the
// functions in CTransInPlaceFilter.  If that's not enough and you want
// to derive your own pin class, override GetPin in the filter to supply
// your own pin classes to the filter.

// ==================================================
// Implements the input pin
// ==================================================

class CTransInPlaceInputPin : public CTransformInputPin
{

protected:
    CTransInPlaceFilter *m_pTIPFilter;

public:

    CTransInPlaceInputPin(
        TCHAR               *pObjectName,
        CTransInPlaceFilter *pFilter,
        HRESULT             *phr,
        LPCWSTR              pName);

    // --- IMemInputPin -----

    // Provide an enumerator for media types by getting one from downstream
    STDMETHODIMP EnumMediaTypes( IEnumMediaTypes **ppEnum );

    // Say whether media type is acceptable.
    HRESULT CheckMediaType(const CMediaType* pmt);

    // Return our upstream allocator
    STDMETHODIMP GetAllocator(IMemAllocator ** ppAllocator);

    // get told which allocator the upstream output pin is actually
    // going to use.
    STDMETHODIMP NotifyAllocator(IMemAllocator * pAllocator,
                    BOOL bReadOnly);

};  // CTransInPlaceInputPin

// ==================================================
// Implements the output pin
// ==================================================

class CTransInPlaceOutputPin : public CTransformOutputPin
{

protected:
    // m_pFilter points to our CBaseFilter
    CTransInPlaceFilter *m_pTIPFilter;

public:

    CTransInPlaceOutputPin(
        TCHAR               *pObjectName,
        CTransInPlaceFilter *pFilter,
        HRESULT             *phr,
        LPCWSTR              pName);


    // --- CBaseOutputPin ------------

    // negotiate the allocator and its buffer size/count
    // Insists on using our own allocator.  (Actually the one upstream of us).
    virtual HRESULT DecideAllocator(IMemInputPin * pPin, IMemAllocator ** pAlloc);

    // get told which allocator the upstream output pin is actually
    // going to use.
    // (This is not an override - output pins don't normally get this)
    STDMETHODIMP NotifyAllocator(IMemAllocator * pAllocator, BOOL bReadOnly);

    // Provide a media type enumerator.  Get it from upstream.
    STDMETHODIMP EnumMediaTypes( IEnumMediaTypes **ppEnum );

    // Say whether media type is acceptable.
    HRESULT CheckMediaType(const CMediaType* pmt);

};  // CTransInPlaceOutputPin


class CTransInPlaceFilter : public CTransformFilter
{

public:

    // map getpin/getpincount for base enum of pins to owner
    // override this to return more specialised pin objects

    virtual CBasePin *GetPin(int n);

public:

    CTransInPlaceFilter(TCHAR *, LPUNKNOWN, CLSID clsid, HRESULT *);

    // The following are defined to avoid undefined pure virtuals.
    // Even if they are never called, they will give linkage warnings/errors

    // We override EnumMediaTypes to bypass the transform class enumerator
    // which would otherwise call this.
    HRESULT GetMediaType(int iPosition, CMediaType *pMediaType)
        {   DbgBreak("CTransInPlaceFilter::GetMediaType should never be called");
            return E_UNEXPECTED;
        }

    // We provide no allocator, so this is never called.
    HRESULT DecideBufferSize(IMemAllocator*, ALLOCATOR_PROPERTIES *)
    {
        DbgBreak("DecideBufferSize has been called for an in-place transform.");
        return E_UNEXPECTED;
    };

    // The functions which call this in CTransform are overridden in this
    // class to call CheckInputType with the assumption that the type
    // does not change.  In Debug builds some calls will be made and
    // we just ensure that they do not assert.
    HRESULT CheckTransform(const CMediaType *mtIn, const CMediaType *mtOut)
    {
        return S_OK;
    };


    // =================================================================
    // ----- You may want to override this -----------------------------
    // =================================================================

    HRESULT CompleteConnect(PIN_DIRECTION dir,IPin *pReceivePin);

    // chance to customize the transform process
    virtual HRESULT Receive(IMediaSample *pSample);

    // =================================================================
    // ----- You MUST override these -----------------------------------
    // =================================================================

    virtual HRESULT Transform(IMediaSample *pSample) PURE;

    // this goes in the factory template table to create new instances
    // static CCOMObject * CreateInstance(LPUNKNOWN, HRESULT *);


#ifdef PERF
    // Override to register performance measurement with a less generic string
    // You should do this to avoid confusion with other filters
    virtual void RegisterPerfId()
         {m_idTransInPlace = MSR_REGISTER(TEXT("TransInPlace"));}
#endif // PERF


// implementation details

protected:

    int m_idTransInPlace;                 // performance measuring id

    // The allocator on our input pin
    IMemAllocator *m_pAllocator;

    // these hold our input and output pins

    friend class CTransInPlaceInputPin;
    friend class CTransInPlaceOutputPin;

    CTransInPlaceInputPin  *InputPin()
    {
        return (CTransInPlaceInputPin *)m_pInput;
    };
    CTransInPlaceOutputPin *OutputPin()
    {
        return (CTransInPlaceOutputPin *)m_pOutput;
    };
}; // CTransInPlaceFilter

#endif /* __TRANSIP__ */