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710 lines
16 KiB
710 lines
16 KiB
/*++
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Microsoft Windows
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Copyright (c) 1994 Microsoft Corporation. All rights reserved.
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Module Name:
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stream.cxx
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Abstract:
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Implements the IStream interface on a memory buffer.
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Author:
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ShannonC 09-Mar-1994
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Environment:
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Windows NT and Windows 95. We do not support DOS and Win16.
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Revision History:
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12-Oct-94 ShannonC Reformat for code review.
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--*/
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#include <ndrp.h>
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#include <ndrole.h>
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class CNdrStream : public IStream
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{
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public:
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virtual HRESULT STDMETHODCALLTYPE
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QueryInterface(
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IN REFIID riid,
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OUT void **ppvObj);
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virtual ULONG STDMETHODCALLTYPE
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AddRef();
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virtual ULONG STDMETHODCALLTYPE
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Release();
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virtual HRESULT STDMETHODCALLTYPE
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Read(
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IN void * pv,
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IN ULONG cb,
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OUT ULONG * pcbRead);
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virtual HRESULT STDMETHODCALLTYPE
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Write(
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IN void const *pv,
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IN ULONG cb,
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OUT ULONG * pcbWritten);
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virtual HRESULT STDMETHODCALLTYPE
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Seek(
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IN LARGE_INTEGER dlibMove,
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IN DWORD dwOrigin,
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OUT ULARGE_INTEGER *plibNewPosition);
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virtual HRESULT STDMETHODCALLTYPE
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SetSize(
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IN ULARGE_INTEGER libNewSize);
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virtual HRESULT STDMETHODCALLTYPE
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CopyTo(
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IN IStream * pstm,
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IN ULARGE_INTEGER cb,
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OUT ULARGE_INTEGER *pcbRead,
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OUT ULARGE_INTEGER *pcbWritten);
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virtual HRESULT STDMETHODCALLTYPE
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Commit(
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IN DWORD grfCommitFlags);
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virtual HRESULT STDMETHODCALLTYPE
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Revert();
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virtual HRESULT STDMETHODCALLTYPE
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LockRegion(
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IN ULARGE_INTEGER libOffset,
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IN ULARGE_INTEGER cb,
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IN DWORD dwLockType);
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virtual HRESULT STDMETHODCALLTYPE
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UnlockRegion(
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IN ULARGE_INTEGER libOffset,
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IN ULARGE_INTEGER cb,
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IN DWORD dwLockType);
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virtual HRESULT STDMETHODCALLTYPE
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Stat(
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OUT STATSTG * pstatstg,
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IN DWORD grfStatFlag);
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virtual HRESULT STDMETHODCALLTYPE
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Clone(
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OUT IStream **ppstm);
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CNdrStream(
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IN unsigned char * pData,
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IN unsigned long cbMax);
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private:
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long RefCount;
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unsigned char * pBuffer;
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unsigned long cbBufferLength;
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unsigned long position;
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};
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EXTERN_C IStream *STDAPICALLTYPE
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NdrpCreateStreamOnMemory(
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IN unsigned char * pData,
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IN unsigned long cbSize)
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/*++
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Routine Description:
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This function creates a stream on the specified memory buffer.
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Arguments:
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pData - Supplies pointer to memory buffer.
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cbSize - Supplies size of memory buffer.
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Return Value:
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This function returns a pointer to the newly created stream.
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--*/
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{
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CNdrStream *pStream = new CNdrStream(pData, cbSize);
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return (IStream *)pStream;
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}
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CNdrStream::CNdrStream(
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IN unsigned char * pData,
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IN unsigned long cbMax)
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: pBuffer(pData), cbBufferLength(cbMax)
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/*++
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Routine Description:
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This function creates a stream on the specified memory buffer.
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Arguments:
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pData - Supplies pointer to memory buffer.
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cbMax - Supplies size of memory buffer.
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Return Value:
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None.
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--*/
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{
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RefCount = 1;
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position = 0;
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}
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ULONG STDMETHODCALLTYPE
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CNdrStream::AddRef()
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/*++
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Routine Description:
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Increment the reference count.
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Arguments:
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Return Value:
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Reference count.
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--*/
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{
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InterlockedIncrement(&RefCount);
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return (ULONG) RefCount;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::Clone(
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OUT IStream **ppstm)
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/*++
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Routine Description:
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Create a new IStream object. The new IStream gets an
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independent seek pointer but it shares the underlying
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data buffer with the original IStream object.
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Arguments:
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ppstm - Pointer to the new stream.
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Return Value:
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S_OK - The stream was successfully copied.
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E_OUTOFMEMORY - The stream could not be copied due to lack of memory.
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--*/
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{
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HRESULT hr;
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CNdrStream *pStream = new CNdrStream(pBuffer, cbBufferLength);
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if(pStream != 0)
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{
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pStream->position = position;
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hr = S_OK;
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}
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else
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{
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hr = E_OUTOFMEMORY;
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}
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*ppstm = (IStream *) pStream;
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return hr;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::Commit(
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IN DWORD grfCommitFlags)
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/*++
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Routine Description:
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This stream does not support transacted mode. This function does nothing.
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Arguments:
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grfCommitFlags
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Return Value:
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S_OK
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--*/
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{
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return S_OK;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::CopyTo(
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IN IStream * pstm,
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IN ULARGE_INTEGER cb,
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OUT ULARGE_INTEGER *pcbRead,
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OUT ULARGE_INTEGER *pcbWritten)
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/*++
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Routine Description:
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Copies data from one stream to another stream.
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Arguments:
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pstm - Specifies the destination stream.
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cb - Specifies the number of bytes to be copied to the destination stream.
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pcbRead - Returns the number of bytes read from the source stream.
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pcbWritten - Returns the number of bytes written to the destination stream.
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Return Value:
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S_OK - The data was successfully copied.
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Other errors from IStream::Write.
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--*/
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{
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HRESULT hr;
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unsigned char * pSource;
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unsigned long cbRead;
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unsigned long cbWritten;
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unsigned long cbRemaining;
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//Check if we are going off the end of the buffer.
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if(position < cbBufferLength)
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cbRemaining = cbBufferLength - position;
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else
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cbRemaining = 0;
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if((cb.HighPart == 0) && (cb.LowPart <= cbRemaining))
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cbRead = cb.LowPart;
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else
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cbRead = cbRemaining;
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pSource = pBuffer + position;
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//copy the data
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hr = pstm->Write(pSource, cbRead, &cbWritten);
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//advance the current position
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position += cbRead;
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if (pcbRead != 0)
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{
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pcbRead->LowPart = cbRead;
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pcbRead->HighPart = 0;
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}
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if (pcbWritten != 0)
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{
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pcbWritten->LowPart = cbWritten;
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pcbWritten->HighPart = 0;
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}
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return hr;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::LockRegion(
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IN ULARGE_INTEGER libOffset,
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IN ULARGE_INTEGER cb,
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IN DWORD dwLockType)
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/*++
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Routine Description:
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Range locking is not supported by this stream.
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Return Value:
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STG_E_INVALIDFUNCTION.
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--*/
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{
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return STG_E_INVALIDFUNCTION;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::QueryInterface(
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REFIID riid,
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void **ppvObj)
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/*++
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Routine Description:
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Query for an interface on the stream. The stream supports
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the IUnknown and IStream interfaces.
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Arguments:
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riid - Supplies the IID of the interface being requested.
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ppvObject - Returns a pointer to the requested interface.
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Return Value:
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S_OK
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E_NOINTERFACE
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--*/
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{
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HRESULT hr;
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if ((memcmp(&riid, &IID_IUnknown, sizeof(IID)) == 0) ||
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(memcmp(&riid, &IID_IStream, sizeof(IID)) == 0))
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{
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this->AddRef();
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*ppvObj = (IStream *) this;
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hr = S_OK;
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}
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else
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{
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*ppvObj = 0;
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hr = E_NOINTERFACE;
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}
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return hr;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::Read(
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OUT void * pv,
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IN ULONG cb,
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OUT ULONG *pcbRead)
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/*++
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Routine Description:
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Reads data from the stream starting at the current seek pointer.
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Arguments:
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pv - Returns the data read from the stream.
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cb - Supplies the number of bytes to read from the stream.
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pcbRead - Returns the number of bytes actually read from the stream.
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Return Value:
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S_OK - The data was successfully read from the stream.
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S_FALSE - The number of bytes read was smaller than the number requested.
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--*/
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{
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HRESULT hr;
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unsigned long cbRead;
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unsigned long cbRemaining;
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//Check if we are reading past the end of the buffer.
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if(position < cbBufferLength)
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cbRemaining = cbBufferLength - position;
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else
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cbRemaining = 0;
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if(cb <= cbRemaining)
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{
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cbRead = cb;
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hr = S_OK;
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}
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else
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{
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cbRead = cbRemaining;
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hr = S_FALSE;
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}
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//copy the data
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RpcpMemoryCopy(pv, pBuffer + position, cbRead);
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//advance the current position
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position += cbRead;
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if(pcbRead != 0)
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*pcbRead = cbRead;
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return hr;
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}
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ULONG STDMETHODCALLTYPE
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CNdrStream::Release()
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/*++
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Routine Description:
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Decrement the reference count. When the reference count
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reaches zero, the stream is deleted.
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Arguments:
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Return Value:
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Reference count.
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--*/
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{
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unsigned long count;
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count = RefCount - 1;
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if(InterlockedDecrement(&RefCount) == 0)
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{
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count = 0;
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delete this;
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}
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return count;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::Revert()
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/*++
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Routine Description:
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This stream does not support transacted mode. This function does nothing.
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Arguments:
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None.
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Return Value:
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S_OK.
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--*/
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{
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return S_OK;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::Seek(
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IN LARGE_INTEGER dlibMove,
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IN DWORD dwOrigin,
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OUT ULARGE_INTEGER *plibNewPosition)
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/*++
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Routine Description:
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Sets the position of the seek pointer. It is an error to seek
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before the beginning of the stream or past the end of the stream.
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Arguments:
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dlibMove - Supplies the offset from the position specified in dwOrigin.
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dwOrigin - Supplies the seek mode.
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plibNewPosition - Returns the new position of the seek pointer.
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Return Value:
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S_OK - The seek pointer was successfully adjusted.
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STG_E_INVALIDFUNCTION - dwOrigin contains invalid value.
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STG_E_SEEKERROR - The seek pointer cannot be positioned before the
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beginning of the stream or past the
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end of the stream.
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--*/
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{
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HRESULT hr;
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long high;
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long low;
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unsigned long offset;
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unsigned long cbRemaining;
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switch (dwOrigin)
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{
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case STREAM_SEEK_SET:
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//Set the seek position relative to the beginning of the stream.
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if((dlibMove.HighPart == 0) && (dlibMove.LowPart <= cbBufferLength))
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{
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position = dlibMove.LowPart;
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hr = S_OK;
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}
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else
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{
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//It is an error to seek past the end of the stream.
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hr = STG_E_SEEKERROR;
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}
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break;
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case STREAM_SEEK_CUR:
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//Set the seek position relative to the current position of the stream.
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high = (long) dlibMove.HighPart;
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if(high < 0)
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{
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//Negative offset
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low = (long) dlibMove.LowPart;
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offset = -low;
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if((high == -1) && (offset <= position))
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{
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position -= offset;
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hr = S_OK;
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}
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else
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{
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//It is an error to seek before the beginning of the stream.
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hr = STG_E_SEEKERROR;
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}
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}
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else
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{
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//Positive offset
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if(position < cbBufferLength)
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cbRemaining = cbBufferLength - position;
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else
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cbRemaining = 0;
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if((dlibMove.HighPart == 0) && (dlibMove.LowPart <= cbRemaining))
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{
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position += dlibMove.LowPart;
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hr = S_OK;
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}
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else
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{
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//It is an error to seek past the end of the stream.
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hr = STG_E_SEEKERROR;
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}
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}
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break;
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case STREAM_SEEK_END:
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//Set the seek position relative to the end of the stream.
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high = (long) dlibMove.HighPart;
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if(high < 0)
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{
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//Negative offset
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low = (long) dlibMove.LowPart;
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offset = -low;
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if((high == -1) && (offset <= cbBufferLength))
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{
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position = cbBufferLength - offset;
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hr = S_OK;
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}
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else
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{
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//It is an error to seek before the beginning of the stream.
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hr = STG_E_SEEKERROR;
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}
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}
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else if(dlibMove.QuadPart == 0)
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{
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position = cbBufferLength;
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hr = S_OK;
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}
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else
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{
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//Positive offset
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//It is an error to seek past the end of the stream.
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hr = STG_E_SEEKERROR;
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}
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break;
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default:
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//dwOrigin contains an invalid value.
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hr = STG_E_INVALIDFUNCTION;
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}
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if (plibNewPosition != 0)
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{
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plibNewPosition->LowPart = position;
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plibNewPosition->HighPart = 0;
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}
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return hr;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::SetSize(
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IN ULARGE_INTEGER libNewSize)
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/*++
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Routine Description:
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Changes the size of the stream.
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Arguments:
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libNewSize - Supplies the new size of the stream.
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Return Value:
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S_OK - The stream size was successfully changed.
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STG_E_MEDIUMFULL - The stream size could not be changed.
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--*/
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{
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HRESULT hr;
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if((libNewSize.HighPart == 0) && (libNewSize.LowPart <= cbBufferLength))
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{
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cbBufferLength = libNewSize.LowPart;
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hr = S_OK;
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}
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else
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{
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hr = STG_E_MEDIUMFULL;
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}
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return hr;
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}
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|
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HRESULT STDMETHODCALLTYPE
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CNdrStream::Stat(
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OUT STATSTG * pstatstg,
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IN DWORD grfStatFlag)
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/*++
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Routine Description:
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This function gets information about this stream.
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Arguments:
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pstatstg - Returns information about this stream.
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grfStatFlg - Specifies the information to be returned in pstatstg.
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Return Value:
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S_OK.
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--*/
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{
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memset(pstatstg, 0, sizeof(STATSTG));
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pstatstg->type = STGTY_STREAM;
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pstatstg->cbSize.LowPart = cbBufferLength;
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pstatstg->cbSize.HighPart = 0;
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return S_OK;
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}
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HRESULT STDMETHODCALLTYPE
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CNdrStream::UnlockRegion(
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IN ULARGE_INTEGER libOffset,
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IN ULARGE_INTEGER cb,
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IN DWORD dwLockType)
|
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/*++
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Routine Description:
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Range locking is not supported by this stream.
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Return Value:
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STG_E_INVALIDFUNCTION.
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--*/
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{
|
|
return STG_E_INVALIDFUNCTION;
|
|
}
|
|
|
|
HRESULT STDMETHODCALLTYPE
|
|
CNdrStream::Write(
|
|
IN void const *pv,
|
|
IN ULONG cb,
|
|
OUT ULONG * pcbWritten)
|
|
/*++
|
|
|
|
Routine Description:
|
|
Write data to the stream starting at the current seek pointer.
|
|
|
|
Arguments:
|
|
pv - Supplies the data to be written to the stream.
|
|
cb - Specifies the number of bytes to be written to the stream.
|
|
pcbWritten - Returns the number of bytes actually written to the stream.
|
|
|
|
Return Value:
|
|
S_OK - The data was successfully written to the stream.
|
|
STG_E_MEDIUMFULL - Data cannot be written past the end of the stream.
|
|
|
|
--*/
|
|
{
|
|
HRESULT hr;
|
|
unsigned long cbRemaining;
|
|
unsigned long cbWritten;
|
|
|
|
//Check if we are writing past the end of the buffer.
|
|
if(position < cbBufferLength)
|
|
cbRemaining = cbBufferLength - position;
|
|
else
|
|
cbRemaining = 0;
|
|
|
|
if(cb <= cbRemaining)
|
|
{
|
|
cbWritten = cb;
|
|
hr = S_OK;
|
|
}
|
|
else
|
|
{
|
|
cbWritten = cbRemaining;
|
|
hr = STG_E_MEDIUMFULL;
|
|
}
|
|
|
|
// Write the data.
|
|
RpcpMemoryCopy(pBuffer + position, pv, cbWritten);
|
|
|
|
//Advance the current position
|
|
position += cbWritten;
|
|
|
|
//update pcbWritten
|
|
if (pcbWritten != 0)
|
|
*pcbWritten = cbWritten;
|
|
|
|
return hr;
|
|
}
|
|
|