copy (2) of streamframe.cpp

基于WINCE的Webcam程序 基于WINCE的Webcam程序 基于WINCE的Webcam程序 基于WINCE的Webcam程序

#include <windows.h>
#include "streamframe.h"

// Implement a FileStream that derives from IStream.
FrameStream::FrameStream(PBYTE pFrame, DWORD dwSize) 
{ 
        _refcount = 0; 
		_pFrameData = pFrame;
		_dwSize = dwSize;
		_dwOffset = 0;
//		_pStream = 0;
//		_dwCheck = 0;
		InitializeCriticalSection (&_cs);

		// Test
//		_pFrameData = (LPBYTE)LocalAlloc (LPTR, dwSize);
//		if (!_pFrameData)
//		{
//			ASSERT (0);
//			return;
//		}
//		memcpy (_pFrameData, pFrame, dwSize);


//		for (DWORD i = 0; i < dwSize; i++)
//			_dwCheck += pFrame[i];

	    // Create the stream
//   HRESULT hr = CreateStreamOnHGlobal(_pFrameData, TRUE, &_pStream);

}

FrameStream::~FrameStream() 
{ 
//		DWORD dw = 0;
//		for (DWORD i = 0; i < _dwSize; i++)
//			dw += _pFrameData[i];
//
//		if (_dwCheck != dw)
//		{
//			DEBUGCHK ((TEXT("*********** Data corrupted!!! *************\r\n")));
//			printf ("*********** Data corrupted!!! *************\r\n");
//		}

//		_pStream->Release();
//		LocalFree (_pFrameData);
		DeleteCriticalSection (&_cs);
}

HRESULT FrameStream::QueryInterface(
    REFIID iid,         // Identifier of the requested interface.
    void ** ppvObject   // Receives an indirect pointer to the object.
    ) 
{ 
        if (iid == __uuidof(IUnknown)
            || iid == __uuidof(IStream)
            || iid == __uuidof(ISequentialStream))
        {
            *ppvObject = static_cast<IStream*>(this);
            AddRef();
            return S_OK;
        } else
            return E_NOINTERFACE; 
}

ULONG FrameStream::AddRef(void) 
{ 
    return (ULONG)InterlockedIncrement(&_refcount); 
}

    ULONG FrameStream::Release(void) 
    {
        ULONG res = (ULONG) InterlockedDecrement(&_refcount);
        if (res == 0) 
            delete this;
        return res;
    }

    // ISequentialStream Interface
    HRESULT FrameStream::Read(void* pv, ULONG cb, ULONG*   pcbRead)
    {
//		return _pStream->Read (pv, cb, pcbRead);


		EnterCriticalSection (&_cs);

		// Limit check
		if ((_dwOffset + cb) > _dwSize)
			cb = _dwSize - _dwOffset;

		memcpy (pv, _pFrameData, cb);
		_dwOffset += cb;
		*pcbRead = cb;

		LeaveCriticalSection (&_cs);
		return S_OK;
    }


    HRESULT FrameStream::
        Seek(LARGE_INTEGER liDistanceToMove, DWORD dwOrigin, ULARGE_INTEGER* lpNewFilePointer)                
    { 

//		return _pStream->Seek (liDistanceToMove, dwOrigin, lpNewFilePointer);


		HRESULT hr = S_OK;
		DWORD dwMove = (DWORD)liDistanceToMove.QuadPart;
        // Check to see if the origin is valid.



		EnterCriticalSection (&_cs);
        switch(dwOrigin)
        {
        case STREAM_SEEK_SET:
			if (dwMove > _dwSize)
				dwMove = _dwSize;

			_dwOffset = dwMove;
            break;
        case STREAM_SEEK_CUR:
			if ((_dwOffset + dwMove) > _dwSize)
				dwMove = _dwSize - _dwOffset;

			_dwOffset += dwMove;
            break;
        case STREAM_SEEK_END:
			if (dwMove > _dwSize)
				_dwOffset = 0;
			else
				_dwOffset = _dwSize - dwMove;
            break;
        default:   
            hr = STG_E_INVALIDFUNCTION;
            break;
        }
		LeaveCriticalSection (&_cs);
        return hr;
    }

    HRESULT FrameStream::Stat(STATSTG* pStatstg, DWORD grfStatFlag) 
    {
//		return _pStream->Stat (pStatstg, grfStatFlag);

		pStatstg->cbSize.QuadPart = _dwSize;
        return S_OK;
    }