lib/ole32/stg_stream.c

   1 /*
   2  * Compound Storage (32 bit version)
   3  * Stream implementation
   4  *
   5  * This file contains the implementation of the stream interface
   6  * for streams contained in a compound storage.
   7  *
   8  * Copyright 1999 Francis Beaudet
   9  * Copyright 1999 Thuy Nguyen
  10  */
  11 #include <stdlib.h>
  12 #include <stdio.h>
  13 #include <string.h>
  14
  15 #include <windows.h>
  16 #include <ddk/ntddk.h>
  17 #include <ole32/ole32.h>
  18 #include "storage32.h"
  19
  20 #include <debug.h>
  21
  22
  23 /*
  24  * Virtual function table for the StgStreamImpl class.
  25  */
  26 static ICOM_VTABLE(IStream) StgStreamImpl_Vtbl =
  27 {
  28     ICOM_MSVTABLE_COMPAT_DummyRTTIVALUE
  29     StgStreamImpl_QueryInterface,
  30     StgStreamImpl_AddRef,
  31     StgStreamImpl_Release,
  32     StgStreamImpl_Read,
  33     StgStreamImpl_Write,
  34     StgStreamImpl_Seek,
  35     StgStreamImpl_SetSize,
  36     StgStreamImpl_CopyTo,
  37     StgStreamImpl_Commit,
  38     StgStreamImpl_Revert,
  39     StgStreamImpl_LockRegion,
  40     StgStreamImpl_UnlockRegion,
  41     StgStreamImpl_Stat,
  42     StgStreamImpl_Clone
  43 };
  44
  45 /******************************************************************************
  46 ** StgStreamImpl implementation
  47 */
  48
  49 /***
  50  * This is the constructor for the StgStreamImpl class.
  51  *
  52  * Params:
  53  *    parentStorage - Pointer to the storage that contains the stream to open
  54  *    ownerProperty - Index of the property that points to this stream.
  55  */
  56 StgStreamImpl* StgStreamImpl_Construct(
  57                 StorageBaseImpl* parentStorage,
  58     DWORD            grfMode,
  59     ULONG            ownerProperty)
  60 {
  61   StgStreamImpl* newStream;
  62
  63   newStream = HeapAlloc(GetProcessHeap(), 0, sizeof(StgStreamImpl));
  64
  65   if (newStream!=0)
  66   {
  67     /*
  68      * Set-up the virtual function table and reference count.
  69      */
  70     ICOM_VTBL(newStream) = &StgStreamImpl_Vtbl;
  71     newStream->ref       = 0;
  72
  73     /*
  74      * We want to nail-down the reference to the storage in case the
  75      * stream out-lives the storage in the client application.
  76      */
  77     newStream->parentStorage = parentStorage;
  78     IStorage_AddRef((IStorage*)newStream->parentStorage);
  79
  80     newStream->grfMode = grfMode;
  81     newStream->ownerProperty = ownerProperty;
  82
  83     /*
  84      * Start the stream at the begining.
  85      */
  86     newStream->currentPosition.u.HighPart = 0;
  87     newStream->currentPosition.u.LowPart = 0;
  88
  89     /*
  90      * Initialize the rest of the data.
  91      */
  92     newStream->streamSize.u.HighPart = 0;
  93     newStream->streamSize.u.LowPart  = 0;
  94     newStream->bigBlockChain       = 0;
  95     newStream->smallBlockChain     = 0;
  96
  97     /*
  98      * Read the size from the property and determine if the blocks forming
  99      * this stream are large or small.
 100      */
 101     StgStreamImpl_OpenBlockChain(newStream);
 102   }
 103
 104   return newStream;
 105 }
 106
 107 /***
 108  * This is the destructor of the StgStreamImpl class.
 109  *
 110  * This method will clean-up all the resources used-up by the given StgStreamImpl
 111  * class. The pointer passed-in to this function will be freed and will not
 112  * be valid anymore.
 113  */
 114 void StgStreamImpl_Destroy(StgStreamImpl* This)
 115 {
 116   Print(MAX_TRACE, ("(%p)\n", This));
 117
 118   /*
 119    * Release the reference we are holding on the parent storage.
 120    */
 121   IStorage_Release((IStorage*)This->parentStorage);
 122   This->parentStorage = 0;
 123
 124   /*
 125    * Make sure we clean-up the block chain stream objects that we were using.
 126    */
 127   if (This->bigBlockChain != 0)
 128   {
 129     BlockChainStream_Destroy(This->bigBlockChain);
 130     This->bigBlockChain = 0;
 131   }
 132
 133   if (This->smallBlockChain != 0)
 134   {
 135     SmallBlockChainStream_Destroy(This->smallBlockChain);
 136     This->smallBlockChain = 0;
 137   }
 138
 139   /*
 140    * Finally, free the memory used-up by the class.
 141    */
 142   HeapFree(GetProcessHeap(), 0, This);
 143 }
 144
 145 /***
 146  * This implements the IUnknown method QueryInterface for this
 147  * class
 148  */
 149 HRESULT WINAPI StgStreamImpl_QueryInterface(
 150                   IStream*     iface,
 151                   REFIID         riid,        /* [in] */
 152                   void**         ppvObject)   /* [iid_is][out] */
 153 {
 154   StgStreamImpl* const This=(StgStreamImpl*)iface;
 155
 156   /*
 157    * Perform a sanity check on the parameters.
 158    */
 159   if (ppvObject==0)
 160     return E_INVALIDARG;
 161
 162   /*
 163    * Initialize the return parameter.
 164    */
 165   *ppvObject = 0;
 166
 167   /*
 168    * Compare the riid with the interface IDs implemented by this object.
 169    */
 170   if (memcmp(&IID_IUnknown, riid, sizeof(IID_IUnknown)) == 0)
 171   {
 172     *ppvObject = (IStream*)This;
 173   }
 174   else if (memcmp(&IID_IStream, riid, sizeof(IID_IStream)) == 0)
 175   {
 176     *ppvObject = (IStream*)This;
 177   }
 178
 179   /*
 180    * Check that we obtained an interface.
 181    */
 182   if ((*ppvObject)==0)
 183     return E_NOINTERFACE;
 184
 185   /*
 186    * Query Interface always increases the reference count by one when it is
 187    * successful
 188    */
 189   StgStreamImpl_AddRef(iface);
 190
 191   return S_OK;;
 192 }
 193
 194 /***
 195  * This implements the IUnknown method AddRef for this
 196  * class
 197  */
 198 ULONG WINAPI StgStreamImpl_AddRef(
 199                 IStream* iface)
 200 {
 201   StgStreamImpl* const This=(StgStreamImpl*)iface;
 202
 203   This->ref++;
 204
 205   return This->ref;
 206 }
 207
 208 /***
 209  * This implements the IUnknown method Release for this
 210  * class
 211  */
 212 ULONG WINAPI StgStreamImpl_Release(
 213                 IStream* iface)
 214 {
 215   StgStreamImpl* const This=(StgStreamImpl*)iface;
 216
 217   ULONG newRef;
 218
 219   This->ref--;
 220
 221   newRef = This->ref;
 222
 223   /*
 224    * If the reference count goes down to 0, perform suicide.
 225    */
 226   if (newRef==0)
 227   {
 228     StgStreamImpl_Destroy(This);
 229   }
 230
 231   return newRef;
 232 }
 233
 234 /***
 235  * This method will open the block chain pointed by the property
 236  * that describes the stream.
 237  * If the stream's size is null, no chain is opened.
 238  */
 239 void StgStreamImpl_OpenBlockChain(
 240         StgStreamImpl* This)
 241 {
 242   StgProperty    curProperty;
 243   BOOL         readSucessful;
 244
 245   /*
 246    * Make sure no old object is staying behind.
 247    */
 248   if (This->smallBlockChain != 0)
 249   {
 250     SmallBlockChainStream_Destroy(This->smallBlockChain);
 251     This->smallBlockChain = 0;
 252   }
 253
 254   if (This->bigBlockChain != 0)
 255   {
 256     BlockChainStream_Destroy(This->bigBlockChain);
 257     This->bigBlockChain = 0;
 258   }
 259
 260   /*
 261    * Read the information from the property.
 262    */
 263   readSucessful = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
 264                                              This->ownerProperty,
 265                                              &curProperty);
 266
 267   if (readSucessful)
 268   {
 269     This->streamSize = curProperty.size;
 270
 271     /*
 272      * This code supports only streams that are <32 bits in size.
 273      */
 274     assert(This->streamSize.u.HighPart == 0);
 275
 276     if(curProperty.startingBlock == BLOCK_END_OF_CHAIN)
 277     {
 278       assert( (This->streamSize.u.HighPart == 0) && (This->streamSize.u.LowPart == 0) );
 279     }
 280     else
 281     {
 282       if ( (This->streamSize.u.HighPart == 0) &&
 283            (This->streamSize.u.LowPart < LIMIT_TO_USE_SMALL_BLOCK) )
 284       {
 285         This->smallBlockChain = SmallBlockChainStream_Construct(
 286                                                                 This->parentStorage->ancestorStorage,
 287                                                                 This->ownerProperty);
 288       }
 289       else
 290       {
 291         This->bigBlockChain = BlockChainStream_Construct(
 292                                                          This->parentStorage->ancestorStorage,
 293                                                          NULL,
 294                                                          This->ownerProperty);
 295       }
 296     }
 297   }
 298 }
 299
 300 /***
 301  * This method is part of the ISequentialStream interface.
 302  *
 303  * If reads a block of information from the stream at the current
 304  * position. It then moves the current position at the end of the
 305  * read block
 306  *
 307  * See the documentation of ISequentialStream for more info.
 308  */
 309 HRESULT WINAPI StgStreamImpl_Read(
 310                   IStream*     iface,
 311                   void*          pv,        /* [length_is][size_is][out] */
 312                   ULONG          cb,        /* [in] */
 313                   ULONG*         pcbRead)   /* [out] */
 314 {
 315   StgStreamImpl* const This=(StgStreamImpl*)iface;
 316
 317   ULONG bytesReadBuffer;
 318   ULONG bytesToReadFromBuffer;
 319
 320   Print(MAX_TRACE, ("(%p, %p, %ld, %p)\n",
 321         iface, pv, cb, pcbRead));
 322
 323   /*
 324    * If the caller is not interested in the nubmer of bytes read,
 325    * we use another buffer to avoid "if" statements in the code.
 326    */
 327   if (pcbRead==0)
 328     pcbRead = &bytesReadBuffer;
 329
 330   /*
 331    * Using the known size of the stream, calculate the number of bytes
 332    * to read from the block chain
 333    */
 334   bytesToReadFromBuffer = min( This->streamSize.u.LowPart - This->currentPosition.u.LowPart, cb);
 335
 336   /*
 337    * Depending on the type of chain that was opened when the stream was constructed,
 338    * we delegate the work to the method that read the block chains.
 339    */
 340   if (This->smallBlockChain!=0)
 341   {
 342     SmallBlockChainStream_ReadAt(This->smallBlockChain,
 343                                  This->currentPosition,
 344                                  bytesToReadFromBuffer,
 345                                  pv,
 346                                  pcbRead);
 347
 348   }
 349   else if (This->bigBlockChain!=0)
 350   {
 351     BlockChainStream_ReadAt(This->bigBlockChain,
 352                             This->currentPosition,
 353                             bytesToReadFromBuffer,
 354                             pv,
 355                             pcbRead);
 356   }
 357   else
 358   {
 359     /*
 360      * Small and big block chains are both NULL. This case will happen
 361      * when a stream starts with BLOCK_END_OF_CHAIN and has size zero.
 362      */
 363
 364     *pcbRead = 0;
 365     return S_OK;
 366   }
 367
 368   /*
 369    * We should always be able to read the proper amount of data from the
 370    * chain.
 371    */
 372   assert(bytesToReadFromBuffer == *pcbRead);
 373
 374   /*
 375    * Advance the pointer for the number of positions read.
 376    */
 377   This->currentPosition.u.LowPart += *pcbRead;
 378
 379   /*
 380    * The function returns S_OK if the buffer was filled completely
 381    * it returns S_FALSE if the end of the stream is reached before the
 382    * buffer is filled
 383    */
 384   if(*pcbRead == cb)
 385     return S_OK;
 386
 387   return S_FALSE;
 388 }
 389
 390 /***
 391  * This method is part of the ISequentialStream interface.
 392  *
 393  * It writes a block of information to the stream at the current
 394  * position. It then moves the current position at the end of the
 395  * written block. If the stream is too small to fit the block,
 396  * the stream is grown to fit.
 397  *
 398  * See the documentation of ISequentialStream for more info.
 399  */
 400 HRESULT WINAPI StgStreamImpl_Write(
 401                   IStream*     iface,
 402                   const void*    pv,          /* [size_is][in] */
 403                   ULONG          cb,          /* [in] */
 404                   ULONG*         pcbWritten)  /* [out] */
 405 {
 406   StgStreamImpl* const This=(StgStreamImpl*)iface;
 407
 408   ULARGE_INTEGER newSize;
 409   ULONG bytesWritten = 0;
 410
 411   Print(MAX_TRACE, ("(%p, %p, %ld, %p)\n",
 412         iface, pv, cb, pcbWritten));
 413
 414   /*
 415    * Do we have permission to write to this stream?
 416    */
 417   if (!(This->grfMode & (STGM_WRITE | STGM_READWRITE))) {
 418       return STG_E_ACCESSDENIED;
 419   }
 420
 421   /*
 422    * If the caller is not interested in the number of bytes written,
 423    * we use another buffer to avoid "if" statements in the code.
 424    */
 425   if (pcbWritten == 0)
 426     pcbWritten = &bytesWritten;
 427
 428   /*
 429    * Initialize the out parameter
 430    */
 431   *pcbWritten = 0;
 432
 433   if (cb == 0)
 434   {
 435     return S_OK;
 436   }
 437   else
 438   {
 439     newSize.u.HighPart = 0;
 440     newSize.u.LowPart = This->currentPosition.u.LowPart + cb;
 441   }
 442
 443   /*
 444    * Verify if we need to grow the stream
 445    */
 446   if (newSize.u.LowPart > This->streamSize.u.LowPart)
 447   {
 448     /* grow stream */
 449     IStream_SetSize(iface, newSize);
 450   }
 451
 452   /*
 453    * Depending on the type of chain that was opened when the stream was constructed,
 454    * we delegate the work to the method that readwrites to the block chains.
 455    */
 456   if (This->smallBlockChain!=0)
 457   {
 458     SmallBlockChainStream_WriteAt(This->smallBlockChain,
 459                                   This->currentPosition,
 460                                   cb,
 461                                   pv,
 462                                   pcbWritten);
 463
 464   }
 465   else if (This->bigBlockChain!=0)
 466   {
 467     BlockChainStream_WriteAt(This->bigBlockChain,
 468                              This->currentPosition,
 469                              cb,
 470                              pv,
 471                              pcbWritten);
 472   }
 473   else
 474     assert(FALSE);
 475
 476   /*
 477    * Advance the position pointer for the number of positions written.
 478    */
 479   This->currentPosition.u.LowPart += *pcbWritten;
 480
 481   return S_OK;
 482 }
 483
 484 /***
 485  * This method is part of the IStream interface.
 486  *
 487  * It will move the current stream pointer according to the parameters
 488  * given.
 489  *
 490  * See the documentation of IStream for more info.
 491  */
 492 HRESULT WINAPI StgStreamImpl_Seek(
 493                   IStream*      iface,
 494                   LARGE_INTEGER   dlibMove,         /* [in] */
 495                   DWORD           dwOrigin,         /* [in] */
 496                   ULARGE_INTEGER* plibNewPosition) /* [out] */
 497 {
 498   StgStreamImpl* const This=(StgStreamImpl*)iface;
 499
 500   ULARGE_INTEGER newPosition;
 501   LARGE_INTEGER Position;
 502
 503   Print(MAX_TRACE, ("(%p, %ld, %ld, %p)\n",
 504         iface, dlibMove.u.LowPart, dwOrigin, plibNewPosition));
 505
 506   /*
 507    * The caller is allowed to pass in NULL as the new position return value.
 508    * If it happens, we assign it to a dynamic variable to avoid special cases
 509    * in the code below.
 510    */
 511   if (plibNewPosition == 0)
 512   {
 513     plibNewPosition = &newPosition;
 514   }
 515
 516   /*
 517    * The file pointer is moved depending on the given "function"
 518    * parameter.
 519    */
 520   switch (dwOrigin)
 521   {
 522     case STREAM_SEEK_SET:
 523       plibNewPosition->u.HighPart = 0;
 524       plibNewPosition->u.LowPart  = 0;
 525       break;
 526     case STREAM_SEEK_CUR:
 527       *plibNewPosition = This->currentPosition;
 528       break;
 529     case STREAM_SEEK_END:
 530       *plibNewPosition = This->streamSize;
 531       break;
 532     default:
 533       return STG_E_INVALIDFUNCTION;
 534   }
 535
 536   Position = RtlLargeIntegerAdd( *((PLARGE_INTEGER)plibNewPosition), dlibMove );
 537
 538   plibNewPosition->QuadPart = Position.QuadPart;
 539
 540   /*
 541    * tell the caller what we calculated
 542    */
 543   This->currentPosition = *plibNewPosition;
 544
 545   return S_OK;
 546 }
 547
 548 /***
 549  * This method is part of the IStream interface.
 550  *
 551  * It will change the size of a stream.
 552  *
 553  * TODO: Switch from small blocks to big blocks and vice versa.
 554  *
 555  * See the documentation of IStream for more info.
 556  */
 557 HRESULT WINAPI StgStreamImpl_SetSize(
 558                                      IStream*      iface,
 559                                      ULARGE_INTEGER  libNewSize)   /* [in] */
 560 {
 561   StgStreamImpl* const This=(StgStreamImpl*)iface;
 562
 563   StgProperty    curProperty;
 564   BOOL         Success;
 565
 566   Print(MAX_TRACE, ("(%p, %ld)\n", iface, libNewSize.u.LowPart));
 567
 568   /*
 569    * As documented.
 570    */
 571   if (libNewSize.u.HighPart != 0)
 572     return STG_E_INVALIDFUNCTION;
 573
 574   /*
 575    * Do we have permission?
 576    */
 577   if (!(This->grfMode & (STGM_WRITE | STGM_READWRITE)))
 578     return STG_E_ACCESSDENIED;
 579
 580   if (This->streamSize.u.LowPart == libNewSize.u.LowPart)
 581     return S_OK;
 582
 583   /*
 584    * This will happen if we're creating a stream
 585    */
 586   if ((This->smallBlockChain == 0) && (This->bigBlockChain == 0))
 587   {
 588     if (libNewSize.u.LowPart < LIMIT_TO_USE_SMALL_BLOCK)
 589     {
 590       This->smallBlockChain = SmallBlockChainStream_Construct(
 591                                     This->parentStorage->ancestorStorage,
 592                                     This->ownerProperty);
 593     }
 594     else
 595     {
 596       This->bigBlockChain = BlockChainStream_Construct(
 597                                 This->parentStorage->ancestorStorage,
 598                                 NULL,
 599                                 This->ownerProperty);
 600     }
 601   }
 602
 603   /*
 604    * Read this stream's property to see if it's small blocks or big blocks
 605    */
 606   Success = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
 607                                        This->ownerProperty,
 608                                        &curProperty);
 609   /*
 610    * Determine if we have to switch from small to big blocks or vice versa
 611    */
 612   if ( (This->smallBlockChain!=0) &&
 613        (curProperty.size.u.LowPart < LIMIT_TO_USE_SMALL_BLOCK) )
 614   {
 615     if (libNewSize.u.LowPart >= LIMIT_TO_USE_SMALL_BLOCK)
 616     {
 617       /*
 618        * Transform the small block chain into a big block chain
 619        */
 620       This->bigBlockChain = Storage32Impl_SmallBlocksToBigBlocks(
 621                                 This->parentStorage->ancestorStorage,
 622                                 &This->smallBlockChain);
 623     }
 624   }
 625
 626   if (This->smallBlockChain!=0)
 627   {
 628     Success = SmallBlockChainStream_SetSize(This->smallBlockChain, libNewSize);
 629   }
 630   else
 631   {
 632     Success = BlockChainStream_SetSize(This->bigBlockChain, libNewSize);
 633   }
 634
 635   /*
 636    * Write to the property the new information about this stream
 637    */
 638   Success = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
 639                                        This->ownerProperty,
 640                                        &curProperty);
 641
 642   curProperty.size.u.HighPart = libNewSize.u.HighPart;
 643   curProperty.size.u.LowPart = libNewSize.u.LowPart;
 644
 645   if (Success)
 646   {
 647     StorageImpl_WriteProperty(This->parentStorage->ancestorStorage,
 648                                 This->ownerProperty,
 649                                 &curProperty);
 650   }
 651
 652   This->streamSize = libNewSize;
 653
 654   return S_OK;
 655 }
 656
 657 /***
 658  * This method is part of the IStream interface.
 659  *
 660  * It will copy the 'cb' Bytes to 'pstm' IStream.
 661  *
 662  * See the documentation of IStream for more info.
 663  */
 664 HRESULT WINAPI StgStreamImpl_CopyTo(
 665                                     IStream*      iface,
 666                                     IStream*      pstm,         /* [unique][in] */
 667                                     ULARGE_INTEGER  cb,           /* [in] */
 668                                     ULARGE_INTEGER* pcbRead,      /* [out] */
 669                                     ULARGE_INTEGER* pcbWritten)   /* [out] */
 670 {
 671   HRESULT        hr = S_OK;
 672   BYTE           tmpBuffer[128];
 673   ULONG          bytesRead, bytesWritten, copySize;
 674   ULARGE_INTEGER totalBytesRead;
 675   ULARGE_INTEGER totalBytesWritten;
 676
 677   Print(MAX_TRACE, ("(%p, %p, %ld, %p, %p)\n",
 678         iface, pstm, cb.u.LowPart, pcbRead, pcbWritten));
 679
 680   /*
 681    * Sanity check
 682    */
 683   if ( pstm == 0 )
 684     return STG_E_INVALIDPOINTER;
 685
 686   totalBytesRead.u.LowPart = totalBytesRead.u.HighPart = 0;
 687   totalBytesWritten.u.LowPart = totalBytesWritten.u.HighPart = 0;
 688
 689   /*
 690    * use stack to store data temporarly
 691    * there is surely more performant way of doing it, for now this basic
 692    * implementation will do the job
 693    */
 694   while ( cb.u.LowPart > 0 )
 695   {
 696     if ( cb.u.LowPart >= 128 )
 697       copySize = 128;
 698     else
 699       copySize = cb.u.LowPart;
 700
 701     IStream_Read(iface, tmpBuffer, copySize, &bytesRead);
 702
 703     totalBytesRead.u.LowPart += bytesRead;
 704
 705     IStream_Write(pstm, tmpBuffer, bytesRead, &bytesWritten);
 706
 707     totalBytesWritten.u.LowPart += bytesWritten;
 708
 709     /*
 710      * Check that read & write operations were succesfull
 711      */
 712     if (bytesRead != bytesWritten)
 713     {
 714       hr = STG_E_MEDIUMFULL;
 715       break;
 716     }
 717
 718     if (bytesRead!=copySize)
 719       cb.u.LowPart = 0;
 720     else
 721       cb.u.LowPart -= bytesRead;
 722   }
 723
 724   /*
 725    * Update number of bytes read and written
 726    */
 727   if (pcbRead)
 728   {
 729     pcbRead->u.LowPart = totalBytesRead.u.LowPart;
 730     pcbRead->u.HighPart = totalBytesRead.u.HighPart;
 731   }
 732
 733   if (pcbWritten)
 734   {
 735     pcbWritten->u.LowPart = totalBytesWritten.u.LowPart;
 736     pcbWritten->u.HighPart = totalBytesWritten.u.HighPart;
 737   }
 738   return hr;
 739 }
 740
 741 /***
 742  * This method is part of the IStream interface.
 743  *
 744  * For streams contained in structured storages, this method
 745  * does nothing. This is what the documentation tells us.
 746  *
 747  * See the documentation of IStream for more info.
 748  */
 749 HRESULT WINAPI StgStreamImpl_Commit(
 750                   IStream*      iface,
 751                   DWORD           grfCommitFlags)  /* [in] */
 752 {
 753   return S_OK;
 754 }
 755
 756 /***
 757  * This method is part of the IStream interface.
 758  *
 759  * For streams contained in structured storages, this method
 760  * does nothing. This is what the documentation tells us.
 761  *
 762  * See the documentation of IStream for more info.
 763  */
 764 HRESULT WINAPI StgStreamImpl_Revert(
 765                   IStream* iface)
 766 {
 767   return S_OK;
 768 }
 769
 770 HRESULT WINAPI StgStreamImpl_LockRegion(
 771                                         IStream*     iface,
 772                                         ULARGE_INTEGER libOffset,   /* [in] */
 773                                         ULARGE_INTEGER cb,          /* [in] */
 774                                         DWORD          dwLockType)  /* [in] */
 775 {
 776   UNIMPLEMENTED;
 777   return E_NOTIMPL;
 778 }
 779
 780 HRESULT WINAPI StgStreamImpl_UnlockRegion(
 781                                           IStream*     iface,
 782                                           ULARGE_INTEGER libOffset,   /* [in] */
 783                                           ULARGE_INTEGER cb,          /* [in] */
 784                                           DWORD          dwLockType)  /* [in] */
 785 {
 786   UNIMPLEMENTED;
 787   return E_NOTIMPL;
 788 }
 789
 790 /***
 791  * This method is part of the IStream interface.
 792  *
 793  * This method returns information about the current
 794  * stream.
 795  *
 796  * See the documentation of IStream for more info.
 797  */
 798 HRESULT WINAPI StgStreamImpl_Stat(
 799                   IStream*     iface,
 800                   STATSTG*       pstatstg,     /* [out] */
 801                   DWORD          grfStatFlag)  /* [in] */
 802 {
 803   StgStreamImpl* const This=(StgStreamImpl*)iface;
 804
 805   StgProperty    curProperty;
 806   BOOL         readSucessful;
 807
 808   /*
 809    * Read the information from the property.
 810    */
 811   readSucessful = StorageImpl_ReadProperty(This->parentStorage->ancestorStorage,
 812                                              This->ownerProperty,
 813                                              &curProperty);
 814
 815   if (readSucessful)
 816   {
 817     StorageUtl_CopyPropertyToSTATSTG(pstatstg,
 818                                      &curProperty,
 819                                      grfStatFlag);
 820
 821     pstatstg->grfMode = This->grfMode;
 822
 823     return S_OK;
 824   }
 825
 826   return E_FAIL;
 827 }
 828
 829 HRESULT WINAPI StgStreamImpl_Clone(
 830                                    IStream*     iface,
 831                                    IStream**    ppstm) /* [out] */
 832 {
 833   UNIMPLEMENTED;
 834   return E_NOTIMPL;
 835 }