C++ IStream_Seek函数代码示例

static UINT msi_dump_stream_to_file( IStream *stm, LPCWSTR name )
{
    ULARGE_INTEGER size;
    LARGE_INTEGER pos;
    IStream *out;
    DWORD stgm;
    HRESULT r;

    stgm = STGM_READWRITE | STGM_SHARE_EXCLUSIVE | STGM_FAILIFTHERE;
    r = SHCreateStreamOnFileW( name, stgm, &out );
    if( FAILED( r ) )
        return ERROR_FUNCTION_FAILED;

    pos.QuadPart = 0;
    r = IStream_Seek( stm, pos, STREAM_SEEK_END, &size );
    if( FAILED( r ) )
        goto end;

    pos.QuadPart = 0;
    r = IStream_Seek( stm, pos, STREAM_SEEK_SET, NULL );
    if( FAILED( r ) )
        goto end;

    r = IStream_CopyTo( stm, out, size, NULL, NULL );

end:
    IStream_Release( out );
    if( FAILED( r ) )
        return ERROR_FUNCTION_FAILED;
    return ERROR_SUCCESS;
}

static inline HRESULT report_data(BindStatusCallback *This)
{
    FORMATETC formatetc = {0, NULL, 1, -1, TYMED_ISTREAM};
    STGMEDIUM stgmedium;
    LARGE_INTEGER off;
    ULARGE_INTEGER size;
    HRESULT hres;

    off.QuadPart = 0;
    hres = IStream_Seek(This->stream, off, STREAM_SEEK_CUR, &size);
    if(FAILED(hres))
        return hres;

    hres = IStream_Seek(This->stream, off, STREAM_SEEK_SET, NULL);
    if(FAILED(hres))
        return hres;

    stgmedium.tymed = TYMED_ISTREAM;
    stgmedium.u.pstm = This->stream;
    stgmedium.pUnkForRelease = NULL;

    hres = IBindStatusCallback_OnDataAvailable(This->bsc,
            BSCF_FIRSTDATANOTIFICATION|BSCF_LASTDATANOTIFICATION,
            size.u.LowPart, &formatetc, &stgmedium);

    IStream_Release(This->stream);
    This->stream = NULL;
    return hres;
}

static HRESULT IDirectMusicSegTriggerTrack_IPersistStream_ParseSegTrackList (LPPERSISTSTREAM iface, DMUS_PRIVATE_CHUNK* pChunk, IStream* pStm) {
  /*ICOM_THIS_MULTI(IDirectMusicSegTriggerTrack, PersistStreamVtbl, iface);*/
  HRESULT hr = E_FAIL;
  DMUS_PRIVATE_CHUNK Chunk;
  DWORD ListSize[3], ListCount[3];
  LARGE_INTEGER liMove; /* used when skipping chunks */

  if (pChunk->fccID != DMUS_FOURCC_SEGTRACK_LIST) {
    ERR_(dmfile)(": %s chunk should be a SEGTRACK list\n", debugstr_fourcc (pChunk->fccID));
    return E_FAIL;
  }  

  ListSize[0] = pChunk->dwSize - sizeof(FOURCC);
  ListCount[0] = 0;

  do {
    IStream_Read (pStm, &Chunk, sizeof(FOURCC)+sizeof(DWORD), NULL);
    ListCount[0] += sizeof(FOURCC) + sizeof(DWORD) + Chunk.dwSize;
    TRACE_(dmfile)(": %s chunk (size = %d)", debugstr_fourcc (Chunk.fccID), Chunk.dwSize);
    switch (Chunk.fccID) { 
    case DMUS_FOURCC_SEGTRACK_CHUNK: {
      TRACE_(dmfile)(": segment trigger track chunk\n");
      liMove.QuadPart = Chunk.dwSize;
      IStream_Seek (pStm, liMove, STREAM_SEEK_CUR, NULL);
      break;
    }
    case FOURCC_LIST: {
      IStream_Read (pStm, &Chunk.fccID, sizeof(FOURCC), NULL);
      TRACE_(dmfile)(": LIST chunk of type %s", debugstr_fourcc(Chunk.fccID));
      ListSize[1] = Chunk.dwSize - sizeof(FOURCC);
      ListCount[1] = 0;
      switch (Chunk.fccID) { 
      case DMUS_FOURCC_SEGMENTS_LIST: {
	TRACE_(dmfile)(": SEGMENTS list\n"); 
	hr = IDirectMusicSegTriggerTrack_IPersistStream_ParseSegmentsList (iface, &Chunk, pStm);
	if (FAILED(hr)) return hr;
	break;
      }
      default: {
	TRACE_(dmfile)(": unknown (skipping)\n");
	liMove.QuadPart = Chunk.dwSize - sizeof(FOURCC);
	IStream_Seek (pStm, liMove, STREAM_SEEK_CUR, NULL);
	break;						
      }
      }	
      break;
    }
    default: {
      TRACE_(dmfile)(": unknown chunk (irrelevant & skipping)\n");
      liMove.QuadPart = Chunk.dwSize;
      IStream_Seek (pStm, liMove, STREAM_SEEK_CUR, NULL);
      break;						
    }
    }
    TRACE_(dmfile)(": ListCount[0] = %d < ListSize[0] = %d\n", ListCount[0], ListSize[0]);
  } while (ListCount[0] < ListSize[0]);

  return S_OK;
}

UINT MSI_RecordReadStream(MSIRECORD *rec, UINT iField, char *buf, LPDWORD sz)
{
    ULONG count;
    HRESULT r;
    IStream *stm;

    TRACE("%p %d %p %p\n", rec, iField, buf, sz);

    if( !sz )
        return ERROR_INVALID_PARAMETER;

    if( iField > rec->count)
        return ERROR_INVALID_PARAMETER;

    if ( rec->fields[iField].type == MSIFIELD_NULL )
    {
        *sz = 0;
        return ERROR_INVALID_DATA;
    }

    if( rec->fields[iField].type != MSIFIELD_STREAM )
        return ERROR_INVALID_DATATYPE;

    stm = rec->fields[iField].u.stream;
    if( !stm )
        return ERROR_INVALID_PARAMETER;

    /* if there's no buffer pointer, calculate the length to the end */
    if( !buf )
    {
        LARGE_INTEGER ofs;
        ULARGE_INTEGER end, cur;

        ofs.QuadPart = cur.QuadPart = 0;
        end.QuadPart = 0;
        IStream_Seek( stm, ofs, STREAM_SEEK_SET, &cur );
        IStream_Seek( stm, ofs, STREAM_SEEK_END, &end );
        ofs.QuadPart = cur.QuadPart;
        IStream_Seek( stm, ofs, STREAM_SEEK_SET, &cur );
        *sz = end.QuadPart - cur.QuadPart;

        return ERROR_SUCCESS;
    }

    /* read the data */
    count = 0;
    r = IStream_Read( stm, buf, *sz, &count );
    if( FAILED( r ) )
    {
        *sz = 0;
        return ERROR_FUNCTION_FAILED;
    }

    *sz = count;

    return ERROR_SUCCESS;
}

static void test_copyto(void)
{
    IStream *pStream, *pStream2;
    HRESULT hr = CreateStreamOnHGlobal(NULL, TRUE, &pStream);
    static const char szHello[] = "Hello";
    ULARGE_INTEGER cb;
    static const char *methods_copyto[] =
    {
        "TestStream_Write",
        NULL
    };
    ULONG written;
    ULARGE_INTEGER ullRead;
    ULARGE_INTEGER ullWritten;
    ULARGE_INTEGER libNewPosition;
    static const LARGE_INTEGER llZero;
    char buffer[15];

    ok_ole_success(hr, "CreateStreamOnHGlobal");

    expected_method_list = methods_copyto;

    hr = IStream_Write(pStream, szHello, sizeof(szHello), &written);
    ok_ole_success(hr, "IStream_Write");
    ok(written == sizeof(szHello), "only %d bytes written\n", written);

    hr = IStream_Seek(pStream, llZero, STREAM_SEEK_SET, NULL);
    ok_ole_success(hr, "IStream_Seek");

    cb.QuadPart = sizeof(szHello);
    hr = IStream_CopyTo(pStream, &Test_Stream, cb, &ullRead, &ullWritten);
    ok(ullWritten.QuadPart == 5, "ullWritten was %d instead\n", (ULONG)ullWritten.QuadPart);
    ok(ullRead.QuadPart == sizeof(szHello), "only %d bytes read\n", (ULONG)ullRead.QuadPart);
    ok_ole_success(hr, "IStream_CopyTo");

    ok(!*expected_method_list, "Method sequence starting from %s not called\n", *expected_method_list);

    hr = IStream_Clone(pStream, &pStream2);
    ok_ole_success(hr, "IStream_Clone");

    hr = IStream_Seek(pStream2, llZero, STREAM_SEEK_CUR, &libNewPosition);
    ok_ole_success(hr, "IStream_Seek");
    ok(libNewPosition.QuadPart == sizeof(szHello), "libNewPosition wasn't set correctly for the cloned stream\n");

    hr = IStream_Seek(pStream2, llZero, STREAM_SEEK_SET, NULL);
    ok_ole_success(hr, "IStream_Seek");

    hr = IStream_Read(pStream2, buffer, sizeof(buffer), NULL);
    ok_ole_success(hr, "IStream_Read");
    ok(!strcmp(buffer, szHello), "read data \"%s\" didn't match originally written data\n", buffer);

    IStream_Release(pStream2);
    IStream_Release(pStream);
}

static void
test_pic(const unsigned char *imgdata, unsigned int imgsize)
{
	LPSTREAM 	stream;
	HGLOBAL		hglob;
	LPBYTE		data;
	HRESULT		hres;
	LARGE_INTEGER	seekto;
	ULARGE_INTEGER	newpos1;

	/* Let the fun begin */
	hglob = GlobalAlloc (0, imgsize);
	data = GlobalLock (hglob);
	memcpy(data, imgdata, imgsize);

	hres = CreateStreamOnHGlobal (hglob, FALSE, &stream);
	ok (hres == S_OK, "createstreamonhglobal failed? doubt it... hres 0x%08lx\n", hres);

	memset(&seekto,0,sizeof(seekto));
	hres = IStream_Seek(stream,seekto,SEEK_CUR,&newpos1);
	ok (hres == S_OK, "istream seek failed? doubt it... hres 0x%08lx\n", hres);
	test_pic_with_stream(stream, imgsize);

	/* again with Non Statable and Non Seekable stream */
	stream = (LPSTREAM)NoStatStreamImpl_Construct(hglob);
	test_pic_with_stream(stream, 0);
}

/*************************************************************************
 * @       [SHLWAPI.166]
 *
 * Determine if a stream has 0 length.
 *
 * PARAMS
 *  lpStream [I] IStream object
 *
 * RETURNS
 *  TRUE:  If the stream has 0 length
 *  FALSE: Otherwise.
 */
BOOL WINAPI SHIsEmptyStream(IStream *lpStream)
{
  STATSTG statstg;
  BOOL bRet = TRUE;

  TRACE("(%p)\n", lpStream);

  memset(&statstg, 0, sizeof(statstg));

  if(SUCCEEDED(IStream_Stat(lpStream, &statstg, 1)))
  {
    if(statstg.cbSize.QuadPart)
      bRet = FALSE; /* Non-Zero */
  }
  else
  {
    DWORD dwDummy;

    /* Try to read from the stream */
    if(SUCCEEDED(SHIStream_Read(lpStream, &dwDummy, sizeof(dwDummy))))
    {
      LARGE_INTEGER zero;
      zero.QuadPart = 0;

      IStream_Seek(lpStream, zero, 0, NULL);
      bRet = FALSE; /* Non-Zero */
    }
  }
  return bRet;
}

/*************************************************************************
 * @       [SHLWAPI.213]
 *
 * Seek to the start of a stream.
 *
 * PARAMS
 *  lpStream [I] IStream object
 *
 * RETURNS
 *  Success: S_OK. The current position within the stream is updated
 *  Failure: An HRESULT error code.
 */
HRESULT WINAPI IStream_Reset(IStream *lpStream)
{
  LARGE_INTEGER zero;
  TRACE("(%p)\n", lpStream);
  zero.QuadPart = 0;
  return IStream_Seek(lpStream, zero, 0, NULL);
}

static HRESULT navigate_history(DocHost *This, unsigned travellog_pos)
{
    IPersistHistory *persist_history;
    travellog_entry_t *entry;
    LARGE_INTEGER li;
    HRESULT hres;

    if(!This->doc_navigate) {
        FIXME("unsupported doc_navigate FALSE\n");
        return E_NOTIMPL;
    }

    This->travellog.loading_pos = travellog_pos;
    entry = This->travellog.log + This->travellog.loading_pos;

    if(!entry->stream)
        return async_doc_navigate(This, entry->url, NULL, NULL, 0, FALSE);

    hres = IUnknown_QueryInterface(This->document, &IID_IPersistHistory, (void**)&persist_history);
    if(FAILED(hres))
        return hres;

    li.QuadPart = 0;
    IStream_Seek(entry->stream, li, STREAM_SEEK_SET, NULL);

    hres = IPersistHistory_LoadHistory(persist_history, entry->stream, NULL);
    IPersistHistory_Release(persist_history);
    return hres;
}

static HRESULT WINAPI IDirectMusicLoaderGenericStream_IStream_Seek (LPSTREAM iface, LARGE_INTEGER dlibMove, DWORD dwOrigin, ULARGE_INTEGER* plibNewPosition) {
	ICOM_THIS_MULTI(IDirectMusicLoaderGenericStream, StreamVtbl, iface);	
	TRACE_(dmfileraw)("(%p, 0x%08llX, %s, %p): redirecting to low-level stream\n", This, dlibMove.QuadPart, resolve_STREAM_SEEK(dwOrigin), plibNewPosition);
	if (!This->pStream)
		return E_FAIL;

	return IStream_Seek (This->pStream, dlibMove, dwOrigin, plibNewPosition);
}

static HRESULT WINAPI IWICStreamImpl_Seek(IWICStream *iface,
    LARGE_INTEGER dlibMove, DWORD dwOrigin, ULARGE_INTEGER *plibNewPosition)
{
    IWICStreamImpl *This = impl_from_IWICStream(iface);
    TRACE("(%p): relay\n", This);

    if (!This->pStream) return WINCODEC_ERR_NOTINITIALIZED;
    return IStream_Seek(This->pStream, dlibMove, dwOrigin, plibNewPosition);
}

static gboolean
gdip_save_bitmap_to_callback (GpBitmap *bitmap,
                              const CLSID *format,
                              const EncoderParameters *encoder_params,
                              GdkPixbufSaveFunc save_func,
                              gpointer user_data,
                              GError **error)
{
  HRESULT hr;  
  IStream *streamOut = NULL;
  gboolean success = FALSE;
  guint64 zero = 0;
  GpStatus status;

  hr = CreateStreamOnHGlobal (NULL, TRUE, &streamOut);
  if (!SUCCEEDED (hr)) {
    gdip_set_error_from_hresult (error, GDK_PIXBUF_ERROR_FAILED, hr, _("Could not create stream: %s"));
    return FALSE;
  }

  status = GdipSaveImageToStream ((GpImage *)bitmap, streamOut, format, encoder_params);
  if (Ok != status) {
    gdip_set_error_from_gpstatus (error, GDK_PIXBUF_ERROR_FAILED, status);
    IStream_Release (streamOut);
    return FALSE;
  }

  /* seek back to the beginning of the stream */
  hr = IStream_Seek (streamOut, *(LARGE_INTEGER *)&zero, STREAM_SEEK_SET, NULL);
  if (!SUCCEEDED (hr)) {
    gdip_set_error_from_hresult (error, GDK_PIXBUF_ERROR_FAILED, hr, _("Could not seek stream: %s"));
    IStream_Release (streamOut);
    return FALSE;
  }
  
  for (;;) {
    char buffer[LOAD_BUFFER_SIZE];
    ULONG nread;
    
    hr = IStream_Read (streamOut, buffer, sizeof(buffer), &nread);
    if (!SUCCEEDED (hr))
      {
        gdip_set_error_from_hresult (error, GDK_PIXBUF_ERROR_FAILED, hr, _("Could not read from stream: %s"));
        break;
      }
    else if (0 == nread) {
      success = TRUE; /* EOF */
      break;
    }
    else if (!(*save_func) (buffer, nread, error, user_data))
      break;
  }
  
  IStream_Release (streamOut);
  
  return success;
}                     

static HRESULT WINAPI IDirectMusicSegTriggerTrack_IPersistStream_Load (LPPERSISTSTREAM iface, IStream* pStm) {
  ICOM_THIS_MULTI(IDirectMusicSegTriggerTrack, PersistStreamVtbl, iface);

  DMUS_PRIVATE_CHUNK Chunk;
  LARGE_INTEGER liMove;
  HRESULT hr;

  TRACE("(%p, %p): Loading\n", This, pStm);
  
#if 1
  IStream_Read (pStm, &Chunk, sizeof(FOURCC)+sizeof(DWORD), NULL);
  TRACE_(dmfile)(": %s chunk (size = %d)", debugstr_fourcc (Chunk.fccID), Chunk.dwSize);
  switch (Chunk.fccID) {	
  case FOURCC_LIST: {
    IStream_Read (pStm, &Chunk.fccID, sizeof(FOURCC), NULL);
    TRACE_(dmfile)(": %s chunk (size = %d)", debugstr_fourcc (Chunk.fccID), Chunk.dwSize);
    switch (Chunk.fccID) {
    case DMUS_FOURCC_SEGTRACK_LIST: {
      TRACE_(dmfile)(": segment trigger track list\n");
      hr = IDirectMusicSegTriggerTrack_IPersistStream_ParseSegTrackList (iface, &Chunk, pStm);
      if (FAILED(hr)) return hr;
      break;    
    }
    default: {
      TRACE_(dmfile)(": unexpected chunk; loading failed)\n");
      liMove.QuadPart = Chunk.dwSize;
      IStream_Seek (pStm, liMove, STREAM_SEEK_CUR, NULL);
      return E_FAIL;
    }
    }
    TRACE_(dmfile)(": reading finished\n");
    break;
  }
  default: {
    TRACE_(dmfile)(": unexpected chunk; loading failed)\n");
    liMove.QuadPart = Chunk.dwSize;
    IStream_Seek (pStm, liMove, STREAM_SEEK_CUR, NULL); /* skip the rest of the chunk */
    return E_FAIL;
  }
  }  
#endif

  return S_OK;
}

static HRESULT BmpFrameDecode_ReadUncompressed(BmpFrameDecode* This)
{
    UINT bytesperrow;
    UINT width, height;
    UINT datasize;
    int bottomup;
    HRESULT hr;
    LARGE_INTEGER offbits;
    ULONG bytesread;

    if (This->bih.bV5Size == sizeof(BITMAPCOREHEADER))
    {
        BITMAPCOREHEADER *bch = (BITMAPCOREHEADER*)&This->bih;
        width = bch->bcWidth;
        height = bch->bcHeight;
        bottomup = 1;
    }
    else
    {
        width = This->bih.bV5Width;
        height = abs(This->bih.bV5Height);
        bottomup = (This->bih.bV5Height > 0);
    }

    /* row sizes in BMP files must be divisible by 4 bytes */
    bytesperrow = (((width * This->bitsperpixel)+31)/32)*4;
    datasize = bytesperrow * height;

    This->imagedata = HeapAlloc(GetProcessHeap(), 0, datasize);
    if (!This->imagedata) return E_OUTOFMEMORY;

    offbits.QuadPart = This->bfh.bfOffBits;
    hr = IStream_Seek(This->stream, offbits, STREAM_SEEK_SET, NULL);
    if (FAILED(hr)) goto fail;

    hr = IStream_Read(This->stream, This->imagedata, datasize, &bytesread);
    if (FAILED(hr) || bytesread != datasize) goto fail;

    if (bottomup)
    {
        This->imagedatastart = This->imagedata + (height-1) * bytesperrow;
        This->stride = -bytesperrow;
    }
    else
    {
        This->imagedatastart = This->imagedata;
        This->stride = bytesperrow;
    }
    return S_OK;

fail:
    HeapFree(GetProcessHeap(), 0, This->imagedata);
    This->imagedata = NULL;
    if (SUCCEEDED(hr)) hr = E_FAIL;
    return hr;
}

static HRESULT WINAPI IDirectMusicBandImpl_IPersistStream_Load (LPPERSISTSTREAM iface, IStream* pStm) {
  ICOM_THIS_MULTI(IDirectMusicBandImpl, PersistStreamVtbl, iface);

  DMUS_PRIVATE_CHUNK Chunk;
  LARGE_INTEGER liMove;
  HRESULT hr;
  
  TRACE("(%p,%p): loading\n", This, pStm);
  
  IStream_Read (pStm, &Chunk, sizeof(FOURCC)+sizeof(DWORD), NULL);
  TRACE_(dmfile)(": %s chunk (size = %d)", debugstr_fourcc (Chunk.fccID), Chunk.dwSize);
  switch (Chunk.fccID) {
  case FOURCC_RIFF: {
    IStream_Read (pStm, &Chunk.fccID, sizeof(FOURCC), NULL);
    TRACE_(dmfile)(": %s chunk (size = %d)", debugstr_fourcc (Chunk.fccID), Chunk.dwSize);
    switch (Chunk.fccID) {
    case DMUS_FOURCC_BAND_FORM: {
      TRACE_(dmfile)(": Band form\n");
      hr = IDirectMusicBandImpl_IPersistStream_ParseBandForm (iface, &Chunk, pStm);
      if (FAILED(hr)) return hr;
      break;    
    }
    default: {
      TRACE_(dmfile)(": unexpected chunk; loading failed)\n");
      liMove.QuadPart = Chunk.dwSize;
      IStream_Seek (pStm, liMove, STREAM_SEEK_CUR, NULL);
      return E_FAIL;
    }
    }
    TRACE_(dmfile)(": reading finished\n");
    break;
  }
  default: {
    TRACE_(dmfile)(": unexpected chunk; loading failed)\n");
    liMove.QuadPart = Chunk.dwSize;
    IStream_Seek (pStm, liMove, STREAM_SEEK_CUR, NULL); /* skip the rest of the chunk */
    return E_FAIL;
  }
  }
  
  return S_OK;
}