dlls/ole32/hglobalstream.c

   1 /*
   2  * HGLOBAL Stream implementation
   3  *
   4  * This file contains the implementation of the stream interface
   5  * for streams contained supported by an HGLOBAL pointer.
   6  *
   7  * Copyright 1999 Francis Beaudet
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  22  */
  23
  24 #include "config.h"
  25
  26 #include <assert.h>
  27 #include <stdlib.h>
  28 #include <stdarg.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31
  32 #define COBJMACROS
  33 #define NONAMELESSUNION
  34 #define NONAMELESSSTRUCT
  35
  36 #include "windef.h"
  37 #include "winbase.h"
  38 #include "winuser.h"
  39 #include "objbase.h"
  40 #include "ole2.h"
  41 #include "winerror.h"
  42 #include "winreg.h"
  43 #include "winternl.h"
  44
  45 #include "wine/debug.h"
  46
  47 WINE_DEFAULT_DEBUG_CHANNEL(storage);
  48
  49 /****************************************************************************
  50  * HGLOBALStreamImpl definition.
  51  *
  52  * This class imlements the IStream inteface and represents a stream
  53  * supported by an HGLOBAL pointer.
  54  */
  55 struct HGLOBALStreamImpl
  56 {
  57   const IStreamVtbl *lpVtbl;   /* Needs to be the first item in the struct
  58                           * since we want to cast this in an IStream pointer */
  59
  60   /*
  61    * Reference count
  62    */
  63   LONG               ref;
  64
  65   /*
  66    * Support for the stream
  67    */
  68   HGLOBAL supportHandle;
  69
  70   /*
  71    * This flag is TRUE if the HGLOBAL is destroyed when the stream
  72    * is finally released.
  73    */
  74   BOOL    deleteOnRelease;
  75
  76   /*
  77    * Helper variable that contains the size of the stream
  78    */
  79   ULARGE_INTEGER     streamSize;
  80
  81   /*
  82    * This is the current position of the cursor in the stream
  83    */
  84   ULARGE_INTEGER     currentPosition;
  85 };
  86
  87 typedef struct HGLOBALStreamImpl HGLOBALStreamImpl;
  88
  89 /***
  90  * This is the destructor of the HGLOBALStreamImpl class.
  91  *
  92  * This method will clean-up all the resources used-up by the given HGLOBALStreamImpl
  93  * class. The pointer passed-in to this function will be freed and will not
  94  * be valid anymore.
  95  */
  96 static void HGLOBALStreamImpl_Destroy(HGLOBALStreamImpl* This)
  97 {
  98   TRACE("(%p)\n", This);
  99
 100   /*
 101    * Release the HGlobal if the constructor asked for that.
 102    */
 103   if (This->deleteOnRelease)
 104   {
 105     GlobalFree(This->supportHandle);
 106     This->supportHandle=0;
 107   }
 108
 109   /*
 110    * Finally, free the memory used-up by the class.
 111    */
 112   HeapFree(GetProcessHeap(), 0, This);
 113 }
 114
 115 /***
 116  * This implements the IUnknown method AddRef for this
 117  * class
 118  */
 119 static ULONG WINAPI HGLOBALStreamImpl_AddRef(
 120                 IStream* iface)
 121 {
 122   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 123   return InterlockedIncrement(&This->ref);
 124 }
 125
 126 /***
 127  * This implements the IUnknown method QueryInterface for this
 128  * class
 129  */
 130 static HRESULT WINAPI HGLOBALStreamImpl_QueryInterface(
 131                   IStream*     iface,
 132                   REFIID         riid,        /* [in] */
 133                   void**         ppvObject)   /* [iid_is][out] */
 134 {
 135   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 136
 137   /*
 138    * Perform a sanity check on the parameters.
 139    */
 140   if (ppvObject==0)
 141     return E_INVALIDARG;
 142
 143   /*
 144    * Initialize the return parameter.
 145    */
 146   *ppvObject = 0;
 147
 148   /*
 149    * Compare the riid with the interface IDs implemented by this object.
 150    */
 151   if (memcmp(&IID_IUnknown, riid, sizeof(IID_IUnknown)) == 0)
 152   {
 153     *ppvObject = (IStream*)This;
 154   }
 155   else if (memcmp(&IID_IStream, riid, sizeof(IID_IStream)) == 0)
 156   {
 157     *ppvObject = (IStream*)This;
 158   }
 159
 160   /*
 161    * Check that we obtained an interface.
 162    */
 163   if ((*ppvObject)==0)
 164     return E_NOINTERFACE;
 165
 166   /*
 167    * Query Interface always increases the reference count by one when it is
 168    * successful
 169    */
 170   HGLOBALStreamImpl_AddRef(iface);
 171
 172   return S_OK;
 173 }
 174
 175 /***
 176  * This implements the IUnknown method Release for this
 177  * class
 178  */
 179 static ULONG WINAPI HGLOBALStreamImpl_Release(
 180                 IStream* iface)
 181 {
 182   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 183   ULONG newRef;
 184
 185   newRef = InterlockedDecrement(&This->ref);
 186
 187   /*
 188    * If the reference count goes down to 0, perform suicide.
 189    */
 190   if (newRef==0)
 191   {
 192     HGLOBALStreamImpl_Destroy(This);
 193   }
 194
 195   return newRef;
 196 }
 197
 198 /***
 199  * This method is part of the ISequentialStream interface.
 200  *
 201  * If reads a block of information from the stream at the current
 202  * position. It then moves the current position at the end of the
 203  * read block
 204  *
 205  * See the documentation of ISequentialStream for more info.
 206  */
 207 static HRESULT WINAPI HGLOBALStreamImpl_Read(
 208                   IStream*     iface,
 209                   void*          pv,        /* [length_is][size_is][out] */
 210                   ULONG          cb,        /* [in] */
 211                   ULONG*         pcbRead)   /* [out] */
 212 {
 213   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 214
 215   void* supportBuffer;
 216   ULONG bytesReadBuffer;
 217   ULONG bytesToReadFromBuffer;
 218
 219   TRACE("(%p, %p, %ld, %p)\n", iface,
 220         pv, cb, pcbRead);
 221
 222   /*
 223    * If the caller is not interested in the nubmer of bytes read,
 224    * we use another buffer to avoid "if" statements in the code.
 225    */
 226   if (pcbRead==0)
 227     pcbRead = &bytesReadBuffer;
 228
 229   /*
 230    * Using the known size of the stream, calculate the number of bytes
 231    * to read from the block chain
 232    */
 233   bytesToReadFromBuffer = min( This->streamSize.u.LowPart - This->currentPosition.u.LowPart, cb);
 234
 235   /*
 236    * Lock the buffer in position and copy the data.
 237    */
 238   supportBuffer = GlobalLock(This->supportHandle);
 239
 240   memcpy(pv, (char *) supportBuffer+This->currentPosition.u.LowPart, bytesToReadFromBuffer);
 241
 242   /*
 243    * Move the current position to the new position
 244    */
 245   This->currentPosition.u.LowPart+=bytesToReadFromBuffer;
 246
 247   /*
 248    * Return the number of bytes read.
 249    */
 250   *pcbRead = bytesToReadFromBuffer;
 251
 252   /*
 253    * Cleanup
 254    */
 255   GlobalUnlock(This->supportHandle);
 256
 257   /*
 258    * The function returns S_OK if the buffer was filled completely
 259    * it returns S_FALSE if the end of the stream is reached before the
 260    * buffer is filled
 261    */
 262   if(*pcbRead == cb)
 263     return S_OK;
 264
 265   return S_FALSE;
 266 }
 267
 268 /***
 269  * This method is part of the ISequentialStream interface.
 270  *
 271  * It writes a block of information to the stream at the current
 272  * position. It then moves the current position at the end of the
 273  * written block. If the stream is too small to fit the block,
 274  * the stream is grown to fit.
 275  *
 276  * See the documentation of ISequentialStream for more info.
 277  */
 278 static HRESULT WINAPI HGLOBALStreamImpl_Write(
 279                   IStream*     iface,
 280                   const void*    pv,          /* [size_is][in] */
 281                   ULONG          cb,          /* [in] */
 282                   ULONG*         pcbWritten)  /* [out] */
 283 {
 284   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 285
 286   void*          supportBuffer;
 287   ULARGE_INTEGER newSize;
 288   ULONG          bytesWritten = 0;
 289
 290   TRACE("(%p, %p, %ld, %p)\n", iface, pv, cb, pcbWritten);
 291
 292   /*
 293    * If the caller is not interested in the number of bytes written,
 294    * we use another buffer to avoid "if" statements in the code.
 295    */
 296   if (pcbWritten == 0)
 297     pcbWritten = &bytesWritten;
 298
 299   if (cb == 0)
 300     goto out;
 301
 302   newSize.u.HighPart = 0;
 303   newSize.u.LowPart = This->currentPosition.u.LowPart + cb;
 304
 305   /*
 306    * Verify if we need to grow the stream
 307    */
 308   if (newSize.u.LowPart > This->streamSize.u.LowPart)
 309   {
 310     /* grow stream */
 311     HRESULT hr = IStream_SetSize(iface, newSize);
 312     if (FAILED(hr))
 313     {
 314       ERR("IStream_SetSize failed with error 0x%08lx\n", hr);
 315       return hr;
 316     }
 317   }
 318
 319   /*
 320    * Lock the buffer in position and copy the data.
 321    */
 322   supportBuffer = GlobalLock(This->supportHandle);
 323
 324   memcpy((char *) supportBuffer+This->currentPosition.u.LowPart, pv, cb);
 325
 326   /*
 327    * Move the current position to the new position
 328    */
 329   This->currentPosition.u.LowPart+=cb;
 330
 331   /*
 332    * Cleanup
 333    */
 334   GlobalUnlock(This->supportHandle);
 335
 336 out:
 337   /*
 338    * Return the number of bytes read.
 339    */
 340   *pcbWritten = cb;
 341
 342   return S_OK;
 343 }
 344
 345 /***
 346  * This method is part of the IStream interface.
 347  *
 348  * It will move the current stream pointer according to the parameters
 349  * given.
 350  *
 351  * See the documentation of IStream for more info.
 352  */
 353 static HRESULT WINAPI HGLOBALStreamImpl_Seek(
 354                   IStream*      iface,
 355                   LARGE_INTEGER   dlibMove,         /* [in] */
 356                   DWORD           dwOrigin,         /* [in] */
 357                   ULARGE_INTEGER* plibNewPosition) /* [out] */
 358 {
 359   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 360
 361   ULARGE_INTEGER newPosition;
 362
 363   TRACE("(%p, %lx%08lx, %ld, %p)\n", iface, dlibMove.u.HighPart,
 364         dlibMove.u.LowPart, dwOrigin, plibNewPosition);
 365
 366   /*
 367    * The file pointer is moved depending on the given "function"
 368    * parameter.
 369    */
 370   switch (dwOrigin)
 371   {
 372     case STREAM_SEEK_SET:
 373       newPosition.u.HighPart = 0;
 374       newPosition.u.LowPart = 0;
 375       break;
 376     case STREAM_SEEK_CUR:
 377       newPosition = This->currentPosition;
 378       break;
 379     case STREAM_SEEK_END:
 380       newPosition = This->streamSize;
 381       break;
 382     default:
 383       return STG_E_INVALIDFUNCTION;
 384   }
 385
 386   /*
 387    * Move the actual file pointer
 388    * If the file pointer ends-up after the end of the stream, the next Write operation will
 389    * make the file larger. This is how it is documented.
 390    */
 391   if (dlibMove.QuadPart < 0 && newPosition.QuadPart < -dlibMove.QuadPart) return STG_E_INVALIDFUNCTION;
 392
 393   newPosition.QuadPart = RtlLargeIntegerAdd(newPosition.QuadPart, dlibMove.QuadPart);
 394
 395   if (plibNewPosition) *plibNewPosition = newPosition;
 396   This->currentPosition = newPosition;
 397
 398   return S_OK;
 399 }
 400
 401 /***
 402  * This method is part of the IStream interface.
 403  *
 404  * It will change the size of a stream.
 405  *
 406  * TODO: Switch from small blocks to big blocks and vice versa.
 407  *
 408  * See the documentation of IStream for more info.
 409  */
 410 static HRESULT WINAPI HGLOBALStreamImpl_SetSize(
 411                                      IStream*      iface,
 412                                      ULARGE_INTEGER  libNewSize)   /* [in] */
 413 {
 414   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 415   HGLOBAL supportHandle;
 416
 417   TRACE("(%p, %ld)\n", iface, libNewSize.u.LowPart);
 418
 419   /*
 420    * As documented.
 421    */
 422   if (libNewSize.u.HighPart != 0)
 423     return STG_E_INVALIDFUNCTION;
 424
 425   if (This->streamSize.u.LowPart == libNewSize.u.LowPart)
 426     return S_OK;
 427
 428   /*
 429    * Re allocate the HGlobal to fit the new size of the stream.
 430    */
 431   supportHandle = GlobalReAlloc(This->supportHandle, libNewSize.u.LowPart, 0);
 432
 433   if (supportHandle == 0)
 434     return STG_E_MEDIUMFULL;
 435
 436   This->supportHandle = supportHandle;
 437   This->streamSize.u.LowPart = libNewSize.u.LowPart;
 438
 439   return S_OK;
 440 }
 441
 442 /***
 443  * This method is part of the IStream interface.
 444  *
 445  * It will copy the 'cb' Bytes to 'pstm' IStream.
 446  *
 447  * See the documentation of IStream for more info.
 448  */
 449 static HRESULT WINAPI HGLOBALStreamImpl_CopyTo(
 450                                     IStream*      iface,
 451                                     IStream*      pstm,         /* [unique][in] */
 452                                     ULARGE_INTEGER  cb,           /* [in] */
 453                                     ULARGE_INTEGER* pcbRead,      /* [out] */
 454                                     ULARGE_INTEGER* pcbWritten)   /* [out] */
 455 {
 456   HRESULT        hr = S_OK;
 457   BYTE           tmpBuffer[128];
 458   ULONG          bytesRead, bytesWritten, copySize;
 459   ULARGE_INTEGER totalBytesRead;
 460   ULARGE_INTEGER totalBytesWritten;
 461
 462   TRACE("(%p, %p, %ld, %p, %p)\n", iface, pstm,
 463         cb.u.LowPart, pcbRead, pcbWritten);
 464
 465   /*
 466    * Sanity check
 467    */
 468   if ( pstm == 0 )
 469     return STG_E_INVALIDPOINTER;
 470
 471   totalBytesRead.u.LowPart = totalBytesRead.u.HighPart = 0;
 472   totalBytesWritten.u.LowPart = totalBytesWritten.u.HighPart = 0;
 473
 474   /*
 475    * use stack to store data temporarly
 476    * there is surely more performant way of doing it, for now this basic
 477    * implementation will do the job
 478    */
 479   while ( cb.u.LowPart > 0 )
 480   {
 481     if ( cb.u.LowPart >= 128 )
 482       copySize = 128;
 483     else
 484       copySize = cb.u.LowPart;
 485
 486     IStream_Read(iface, tmpBuffer, copySize, &bytesRead);
 487
 488     totalBytesRead.u.LowPart += bytesRead;
 489
 490     IStream_Write(pstm, tmpBuffer, bytesRead, &bytesWritten);
 491
 492     totalBytesWritten.u.LowPart += bytesWritten;
 493
 494     /*
 495      * Check that read & write operations were succesfull
 496      */
 497     if (bytesRead != bytesWritten)
 498     {
 499       hr = STG_E_MEDIUMFULL;
 500       break;
 501     }
 502
 503     if (bytesRead!=copySize)
 504       cb.u.LowPart = 0;
 505     else
 506       cb.u.LowPart -= bytesRead;
 507   }
 508
 509   /*
 510    * Update number of bytes read and written
 511    */
 512   if (pcbRead)
 513   {
 514     pcbRead->u.LowPart = totalBytesRead.u.LowPart;
 515     pcbRead->u.HighPart = totalBytesRead.u.HighPart;
 516   }
 517
 518   if (pcbWritten)
 519   {
 520     pcbWritten->u.LowPart = totalBytesWritten.u.LowPart;
 521     pcbWritten->u.HighPart = totalBytesWritten.u.HighPart;
 522   }
 523   return hr;
 524 }
 525
 526 /***
 527  * This method is part of the IStream interface.
 528  *
 529  * For streams supported by HGLOBALS, this function does nothing.
 530  * This is what the documentation tells us.
 531  *
 532  * See the documentation of IStream for more info.
 533  */
 534 static HRESULT WINAPI HGLOBALStreamImpl_Commit(
 535                   IStream*      iface,
 536                   DWORD         grfCommitFlags)  /* [in] */
 537 {
 538   return S_OK;
 539 }
 540
 541 /***
 542  * This method is part of the IStream interface.
 543  *
 544  * For streams supported by HGLOBALS, this function does nothing.
 545  * This is what the documentation tells us.
 546  *
 547  * See the documentation of IStream for more info.
 548  */
 549 static HRESULT WINAPI HGLOBALStreamImpl_Revert(
 550                   IStream* iface)
 551 {
 552   return S_OK;
 553 }
 554
 555 /***
 556  * This method is part of the IStream interface.
 557  *
 558  * For streams supported by HGLOBALS, this function does nothing.
 559  * This is what the documentation tells us.
 560  *
 561  * See the documentation of IStream for more info.
 562  */
 563 static HRESULT WINAPI HGLOBALStreamImpl_LockRegion(
 564                   IStream*       iface,
 565                   ULARGE_INTEGER libOffset,   /* [in] */
 566                   ULARGE_INTEGER cb,          /* [in] */
 567                   DWORD          dwLockType)  /* [in] */
 568 {
 569   return S_OK;
 570 }
 571
 572 /*
 573  * This method is part of the IStream interface.
 574  *
 575  * For streams supported by HGLOBALS, this function does nothing.
 576  * This is what the documentation tells us.
 577  *
 578  * See the documentation of IStream for more info.
 579  */
 580 static HRESULT WINAPI HGLOBALStreamImpl_UnlockRegion(
 581                   IStream*       iface,
 582                   ULARGE_INTEGER libOffset,   /* [in] */
 583                   ULARGE_INTEGER cb,          /* [in] */
 584                   DWORD          dwLockType)  /* [in] */
 585 {
 586   return S_OK;
 587 }
 588
 589 /***
 590  * This method is part of the IStream interface.
 591  *
 592  * This method returns information about the current
 593  * stream.
 594  *
 595  * See the documentation of IStream for more info.
 596  */
 597 static HRESULT WINAPI HGLOBALStreamImpl_Stat(
 598                   IStream*     iface,
 599                   STATSTG*     pstatstg,     /* [out] */
 600                   DWORD        grfStatFlag)  /* [in] */
 601 {
 602   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 603
 604   memset(pstatstg, 0, sizeof(STATSTG));
 605
 606   pstatstg->pwcsName = NULL;
 607   pstatstg->type     = STGTY_STREAM;
 608   pstatstg->cbSize   = This->streamSize;
 609
 610   return S_OK;
 611 }
 612
 613 static HRESULT WINAPI HGLOBALStreamImpl_Clone(
 614                   IStream*     iface,
 615                   IStream**    ppstm) /* [out] */
 616 {
 617   ULARGE_INTEGER dummy;
 618   LARGE_INTEGER offset;
 619   HRESULT hr;
 620   HGLOBALStreamImpl* const This=(HGLOBALStreamImpl*)iface;
 621   TRACE(" Cloning %p (deleteOnRelease=%d seek position=%ld)\n",iface,This->deleteOnRelease,(long)This->currentPosition.QuadPart);
 622   hr=CreateStreamOnHGlobal(This->supportHandle, FALSE, ppstm);
 623   if(FAILED(hr))
 624     return hr;
 625   offset.QuadPart=(LONGLONG)This->currentPosition.QuadPart;
 626   HGLOBALStreamImpl_Seek(*ppstm,offset,STREAM_SEEK_SET,&dummy);
 627   return S_OK;
 628 }
 629
 630 /*
 631  * Virtual function table for the HGLOBALStreamImpl class.
 632  */
 633 static const IStreamVtbl HGLOBALStreamImpl_Vtbl =
 634 {
 635     HGLOBALStreamImpl_QueryInterface,
 636     HGLOBALStreamImpl_AddRef,
 637     HGLOBALStreamImpl_Release,
 638     HGLOBALStreamImpl_Read,
 639     HGLOBALStreamImpl_Write,
 640     HGLOBALStreamImpl_Seek,
 641     HGLOBALStreamImpl_SetSize,
 642     HGLOBALStreamImpl_CopyTo,
 643     HGLOBALStreamImpl_Commit,
 644     HGLOBALStreamImpl_Revert,
 645     HGLOBALStreamImpl_LockRegion,
 646     HGLOBALStreamImpl_UnlockRegion,
 647     HGLOBALStreamImpl_Stat,
 648     HGLOBALStreamImpl_Clone
 649 };
 650
 651 /******************************************************************************
 652 ** HGLOBALStreamImpl implementation
 653 */
 654
 655 /***
 656  * This is the constructor for the HGLOBALStreamImpl class.
 657  *
 658  * Params:
 659  *    hGlobal          - Handle that will support the stream. can be NULL.
 660  *    fDeleteOnRelease - Flag set to TRUE if the HGLOBAL will be released
 661  *                       when the IStream object is destroyed.
 662  */
 663 HGLOBALStreamImpl* HGLOBALStreamImpl_Construct(
 664                 HGLOBAL  hGlobal,
 665                 BOOL     fDeleteOnRelease)
 666 {
 667   HGLOBALStreamImpl* newStream;
 668
 669   newStream = HeapAlloc(GetProcessHeap(), 0, sizeof(HGLOBALStreamImpl));
 670
 671   if (newStream!=0)
 672   {
 673     /*
 674      * Set-up the virtual function table and reference count.
 675      */
 676     newStream->lpVtbl = &HGLOBALStreamImpl_Vtbl;
 677     newStream->ref    = 0;
 678
 679     /*
 680      * Initialize the support.
 681      */
 682     newStream->supportHandle = hGlobal;
 683     newStream->deleteOnRelease = fDeleteOnRelease;
 684
 685     /*
 686      * This method will allocate a handle if one is not supplied.
 687      */
 688     if (!newStream->supportHandle)
 689     {
 690       newStream->supportHandle = GlobalAlloc(GMEM_MOVEABLE | GMEM_NODISCARD |
 691                                              GMEM_SHARE, 0);
 692     }
 693
 694     /*
 695      * Start the stream at the beginning.
 696      */
 697     newStream->currentPosition.u.HighPart = 0;
 698     newStream->currentPosition.u.LowPart = 0;
 699
 700     /*
 701      * Initialize the size of the stream to the size of the handle.
 702      */
 703     newStream->streamSize.u.HighPart = 0;
 704     newStream->streamSize.u.LowPart  = GlobalSize(newStream->supportHandle);
 705   }
 706
 707   return newStream;
 708 }
 709
 710
 711 /***********************************************************************
 712  *           CreateStreamOnHGlobal     [OLE32.@]
 713  */
 714 HRESULT WINAPI CreateStreamOnHGlobal(
 715                 HGLOBAL   hGlobal,
 716                 BOOL      fDeleteOnRelease,
 717                 LPSTREAM* ppstm)
 718 {
 719   HGLOBALStreamImpl* newStream;
 720
 721   newStream = HGLOBALStreamImpl_Construct(hGlobal,
 722                                           fDeleteOnRelease);
 723
 724   if (newStream!=NULL)
 725   {
 726     return IUnknown_QueryInterface((IUnknown*)newStream,
 727                                    &IID_IStream,
 728                                    (void**)ppstm);
 729   }
 730
 731   return E_OUTOFMEMORY;
 732 }
 733
 734 /***********************************************************************
 735  *           GetHGlobalFromStream     [OLE32.@]
 736  */
 737 HRESULT WINAPI GetHGlobalFromStream(IStream* pstm, HGLOBAL* phglobal)
 738 {
 739   HGLOBALStreamImpl* pStream;
 740
 741   if (pstm == NULL)
 742     return E_INVALIDARG;
 743
 744   pStream = (HGLOBALStreamImpl*) pstm;
 745
 746   /*
 747    * Verify that the stream object was created with CreateStreamOnHGlobal.
 748    */
 749   if (pStream->lpVtbl == &HGLOBALStreamImpl_Vtbl)
 750     *phglobal = pStream->supportHandle;
 751   else
 752   {
 753     *phglobal = 0;
 754     return E_INVALIDARG;
 755   }
 756
 757   return S_OK;
 758 }