dll/win32/shlwapi/istream.c

   1 /*
   2  * SHLWAPI IStream functions
   3  *
   4  * Copyright 2002 Jon Griffiths
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include "precomp.h"
  22
  23 #define STGM_ACCESS_MODE(stgm)   ((stgm)&0x0000f)
  24 #define STGM_SHARE_MODE(stgm)    ((stgm)&0x000f0)
  25 #define STGM_CREATE_MODE(stgm)   ((stgm)&0x0f000)
  26
  27 /* Layout of ISHFileStream object */
  28 typedef struct
  29 {
  30   IStream  IStream_iface;
  31   LONG     ref;
  32   HANDLE   hFile;
  33   DWORD    dwMode;
  34   LPOLESTR lpszPath;
  35   DWORD    type;
  36   DWORD    grfStateBits;
  37 } ISHFileStream;
  38
  39 static inline ISHFileStream *impl_from_IStream(IStream *iface)
  40 {
  41   return CONTAINING_RECORD(iface, ISHFileStream, IStream_iface);
  42 }
  43
  44 static HRESULT WINAPI IStream_fnCommit(IStream*,DWORD);
  45
  46
  47 /**************************************************************************
  48 *  IStream_fnQueryInterface
  49 */
  50 static HRESULT WINAPI IStream_fnQueryInterface(IStream *iface, REFIID riid, LPVOID *ppvObj)
  51 {
  52   ISHFileStream *This = impl_from_IStream(iface);
  53
  54   TRACE("(%p,%s,%p)\n", This, debugstr_guid(riid), ppvObj);
  55
  56   *ppvObj = NULL;
  57
  58   if(IsEqualIID(riid, &IID_IUnknown) ||
  59      IsEqualIID(riid, &IID_IStream))
  60   {
  61     IStream_AddRef(iface);
  62     *ppvObj = iface;
  63     return S_OK;
  64   }
  65   return E_NOINTERFACE;
  66 }
  67
  68 /**************************************************************************
  69 *  IStream_fnAddRef
  70 */
  71 static ULONG WINAPI IStream_fnAddRef(IStream *iface)
  72 {
  73   ISHFileStream *This = impl_from_IStream(iface);
  74   ULONG refCount = InterlockedIncrement(&This->ref);
  75
  76   TRACE("(%p)->(ref before=%u)\n",This, refCount - 1);
  77
  78   return refCount;
  79 }
  80
  81 /**************************************************************************
  82 *  IStream_fnRelease
  83 */
  84 static ULONG WINAPI IStream_fnRelease(IStream *iface)
  85 {
  86   ISHFileStream *This = impl_from_IStream(iface);
  87   ULONG refCount = InterlockedDecrement(&This->ref);
  88
  89   TRACE("(%p)->(ref before=%u)\n",This, refCount + 1);
  90
  91   if (!refCount)
  92   {
  93     IStream_fnCommit(iface, 0); /* If ever buffered, this will be needed */
  94     LocalFree(This->lpszPath);
  95     CloseHandle(This->hFile);
  96     HeapFree(GetProcessHeap(), 0, This);
  97   }
  98
  99   return refCount;
 100 }
 101
 102 /**************************************************************************
 103  * IStream_fnRead
 104  */
 105 static HRESULT WINAPI IStream_fnRead(IStream *iface, void* pv, ULONG cb, ULONG* pcbRead)
 106 {
 107   ISHFileStream *This = impl_from_IStream(iface);
 108   DWORD dwRead = 0;
 109
 110   TRACE("(%p,%p,0x%08x,%p)\n", This, pv, cb, pcbRead);
 111
 112   if (!ReadFile(This->hFile, pv, cb, &dwRead, NULL))
 113   {
 114     WARN("error %d reading file\n", GetLastError());
 115     return S_FALSE;
 116   }
 117   if (pcbRead)
 118     *pcbRead = dwRead;
 119   return S_OK;
 120 }
 121
 122 /**************************************************************************
 123  * IStream_fnWrite
 124  */
 125 static HRESULT WINAPI IStream_fnWrite(IStream *iface, const void* pv, ULONG cb, ULONG* pcbWritten)
 126 {
 127   ISHFileStream *This = impl_from_IStream(iface);
 128   DWORD dwWritten = 0;
 129
 130   TRACE("(%p,%p,0x%08x,%p)\n", This, pv, cb, pcbWritten);
 131
 132   switch (STGM_ACCESS_MODE(This->dwMode))
 133   {
 134   case STGM_WRITE:
 135   case STGM_READWRITE:
 136     break;
 137   default:
 138     return STG_E_ACCESSDENIED;
 139   }
 140
 141   if (!WriteFile(This->hFile, pv, cb, &dwWritten, NULL))
 142     return HRESULT_FROM_WIN32(GetLastError());
 143
 144   if (pcbWritten)
 145     *pcbWritten = dwWritten;
 146   return S_OK;
 147 }
 148
 149 /**************************************************************************
 150  *  IStream_fnSeek
 151  */
 152 static HRESULT WINAPI IStream_fnSeek(IStream *iface, LARGE_INTEGER dlibMove,
 153                                      DWORD dwOrigin, ULARGE_INTEGER* pNewPos)
 154 {
 155   ISHFileStream *This = impl_from_IStream(iface);
 156   DWORD dwPos;
 157
 158   TRACE("(%p,%d,%d,%p)\n", This, dlibMove.u.LowPart, dwOrigin, pNewPos);
 159
 160   IStream_fnCommit(iface, 0); /* If ever buffered, this will be needed */
 161   dwPos = SetFilePointer(This->hFile, dlibMove.u.LowPart, NULL, dwOrigin);
 162   if( dwPos == INVALID_SET_FILE_POINTER )
 163      return HRESULT_FROM_WIN32(GetLastError());
 164
 165   if (pNewPos)
 166   {
 167     pNewPos->u.HighPart = 0;
 168     pNewPos->u.LowPart = dwPos;
 169   }
 170   return S_OK;
 171 }
 172
 173 /**************************************************************************
 174  * IStream_fnSetSize
 175  */
 176 static HRESULT WINAPI IStream_fnSetSize(IStream *iface, ULARGE_INTEGER libNewSize)
 177 {
 178   ISHFileStream *This = impl_from_IStream(iface);
 179
 180   TRACE("(%p,%d)\n", This, libNewSize.u.LowPart);
 181
 182   IStream_fnCommit(iface, 0); /* If ever buffered, this will be needed */
 183   if( ! SetFilePointer( This->hFile, libNewSize.QuadPart, NULL, FILE_BEGIN ) )
 184     return E_FAIL;
 185
 186   if( ! SetEndOfFile( This->hFile ) )
 187     return E_FAIL;
 188
 189   return S_OK;
 190 }
 191
 192 /**************************************************************************
 193  * IStream_fnCopyTo
 194  */
 195 static HRESULT WINAPI IStream_fnCopyTo(IStream *iface, IStream* pstm, ULARGE_INTEGER cb,
 196                                        ULARGE_INTEGER* pcbRead, ULARGE_INTEGER* pcbWritten)
 197 {
 198   ISHFileStream *This = impl_from_IStream(iface);
 199   char copyBuff[1024];
 200   ULONGLONG ulSize;
 201   HRESULT hRet = S_OK;
 202
 203   TRACE("(%p,%p,%d,%p,%p)\n", This, pstm, cb.u.LowPart, pcbRead, pcbWritten);
 204
 205   if (pcbRead)
 206     pcbRead->QuadPart = 0;
 207   if (pcbWritten)
 208     pcbWritten->QuadPart = 0;
 209
 210   if (!pstm)
 211     return S_OK;
 212
 213   IStream_fnCommit(iface, 0); /* If ever buffered, this will be needed */
 214
 215   /* Copy data */
 216   ulSize = cb.QuadPart;
 217   while (ulSize)
 218   {
 219     ULONG ulLeft, ulRead, ulWritten;
 220
 221     ulLeft = ulSize > sizeof(copyBuff) ? sizeof(copyBuff) : ulSize;
 222
 223     /* Read */
 224     hRet = IStream_fnRead(iface, copyBuff, ulLeft, &ulRead);
 225     if (FAILED(hRet) || ulRead == 0)
 226       break;
 227     if (pcbRead)
 228       pcbRead->QuadPart += ulRead;
 229
 230     /* Write */
 231     hRet = IStream_fnWrite(pstm, copyBuff, ulRead, &ulWritten);
 232     if (pcbWritten)
 233       pcbWritten->QuadPart += ulWritten;
 234     if (FAILED(hRet) || ulWritten != ulLeft)
 235       break;
 236
 237     ulSize -= ulLeft;
 238   }
 239   return hRet;
 240 }
 241
 242 /**************************************************************************
 243  * IStream_fnCommit
 244  */
 245 static HRESULT WINAPI IStream_fnCommit(IStream *iface, DWORD grfCommitFlags)
 246 {
 247   ISHFileStream *This = impl_from_IStream(iface);
 248
 249   TRACE("(%p,%d)\n", This, grfCommitFlags);
 250   /* Currently unbuffered: This function is not needed */
 251   return S_OK;
 252 }
 253
 254 /**************************************************************************
 255  * IStream_fnRevert
 256  */
 257 static HRESULT WINAPI IStream_fnRevert(IStream *iface)
 258 {
 259   ISHFileStream *This = impl_from_IStream(iface);
 260
 261   TRACE("(%p)\n", This);
 262   return E_NOTIMPL;
 263 }
 264
 265 /**************************************************************************
 266  * IStream_fnLockUnlockRegion
 267  */
 268 static HRESULT WINAPI IStream_fnLockUnlockRegion(IStream *iface, ULARGE_INTEGER libOffset,
 269                                                  ULARGE_INTEGER cb, DWORD dwLockType)
 270 {
 271   ISHFileStream *This = impl_from_IStream(iface);
 272   TRACE("(%p,%d,%d,%d)\n", This, libOffset.u.LowPart, cb.u.LowPart, dwLockType);
 273   return E_NOTIMPL;
 274 }
 275
 276 /*************************************************************************
 277  * IStream_fnStat
 278  */
 279 static HRESULT WINAPI IStream_fnStat(IStream *iface, STATSTG* lpStat,
 280                                      DWORD grfStatFlag)
 281 {
 282     ISHFileStream *This = impl_from_IStream(iface);
 283     BY_HANDLE_FILE_INFORMATION fi;
 284
 285     TRACE("(%p,%p,%d)\n", This, lpStat, grfStatFlag);
 286
 287     if (!grfStatFlag)
 288         return STG_E_INVALIDPOINTER;
 289
 290     memset(&fi, 0, sizeof(fi));
 291     GetFileInformationByHandle(This->hFile, &fi);
 292
 293     if (grfStatFlag & STATFLAG_NONAME)
 294       lpStat->pwcsName = NULL;
 295     else
 296       lpStat->pwcsName = StrDupW(This->lpszPath);
 297     lpStat->type = This->type;
 298     lpStat->cbSize.u.LowPart = fi.nFileSizeLow;
 299     lpStat->cbSize.u.HighPart = fi.nFileSizeHigh;
 300     lpStat->mtime = fi.ftLastWriteTime;
 301     lpStat->ctime = fi.ftCreationTime;
 302     lpStat->atime = fi.ftLastAccessTime;
 303     lpStat->grfMode = This->dwMode;
 304     lpStat->grfLocksSupported = 0;
 305     memcpy(&lpStat->clsid, &IID_IStream, sizeof(CLSID));
 306     lpStat->grfStateBits = This->grfStateBits;
 307     lpStat->reserved = 0;
 308
 309     return S_OK;
 310 }
 311
 312 /*************************************************************************
 313  * IStream_fnClone
 314  */
 315 static HRESULT WINAPI IStream_fnClone(IStream *iface, IStream** ppstm)
 316 {
 317   ISHFileStream *This = impl_from_IStream(iface);
 318
 319   TRACE("(%p)\n",This);
 320   if (ppstm)
 321     *ppstm = NULL;
 322   return E_NOTIMPL;
 323 }
 324
 325 static const IStreamVtbl SHLWAPI_fsVTable =
 326 {
 327   IStream_fnQueryInterface,
 328   IStream_fnAddRef,
 329   IStream_fnRelease,
 330   IStream_fnRead,
 331   IStream_fnWrite,
 332   IStream_fnSeek,
 333   IStream_fnSetSize,
 334   IStream_fnCopyTo,
 335   IStream_fnCommit,
 336   IStream_fnRevert,
 337   IStream_fnLockUnlockRegion,
 338   IStream_fnLockUnlockRegion,
 339   IStream_fnStat,
 340   IStream_fnClone
 341 };
 342
 343 /**************************************************************************
 344  * IStream_Create
 345  *
 346  * Internal helper: Create and initialise a new file stream object.
 347  */
 348 static IStream *IStream_Create(LPCWSTR lpszPath, HANDLE hFile, DWORD dwMode)
 349 {
 350     ISHFileStream *fileStream;
 351
 352     fileStream = HeapAlloc(GetProcessHeap(), 0, sizeof(ISHFileStream));
 353     if (!fileStream) return NULL;
 354
 355     fileStream->IStream_iface.lpVtbl = &SHLWAPI_fsVTable;
 356     fileStream->ref = 1;
 357     fileStream->hFile = hFile;
 358     fileStream->dwMode = dwMode;
 359     fileStream->lpszPath = StrDupW(lpszPath);
 360     fileStream->type = 0; /* FIXME */
 361     fileStream->grfStateBits = 0; /* FIXME */
 362
 363     TRACE ("Returning %p\n", fileStream);
 364     return &fileStream->IStream_iface;
 365 }
 366
 367 /*************************************************************************
 368  * SHCreateStreamOnFileEx   [SHLWAPI.@]
 369  *
 370  * Create a stream on a file.
 371  *
 372  * PARAMS
 373  *  lpszPath     [I] Path of file to create stream on
 374  *  dwMode       [I] Mode to create stream in
 375  *  dwAttributes [I] Attributes of the file
 376  *  bCreate      [I] Whether to create the file if it doesn't exist
 377  *  lpTemplate   [I] Reserved, must be NULL
 378  *  lppStream    [O] Destination for created stream
 379  *
 380  * RETURNS
 381  * Success: S_OK. lppStream contains the new stream object
 382  * Failure: E_INVALIDARG if any parameter is invalid, or an HRESULT error code
 383  *
 384  * NOTES
 385  *  This function is available in Unicode only.
 386  */
 387 HRESULT WINAPI SHCreateStreamOnFileEx(LPCWSTR lpszPath, DWORD dwMode,
 388                                       DWORD dwAttributes, BOOL bCreate,
 389                                       IStream *lpTemplate, IStream **lppStream)
 390 {
 391   DWORD dwAccess, dwShare, dwCreate;
 392   HANDLE hFile;
 393
 394   TRACE("(%s,%d,0x%08X,%d,%p,%p)\n", debugstr_w(lpszPath), dwMode,
 395         dwAttributes, bCreate, lpTemplate, lppStream);
 396
 397   if (!lpszPath || !lppStream || lpTemplate)
 398     return E_INVALIDARG;
 399
 400   *lppStream = NULL;
 401
 402   /* Access */
 403   switch (STGM_ACCESS_MODE(dwMode))
 404   {
 405   case STGM_WRITE:
 406   case STGM_READWRITE:
 407     dwAccess = GENERIC_READ|GENERIC_WRITE;
 408     break;
 409   case STGM_READ:
 410     dwAccess = GENERIC_READ;
 411     break;
 412   default:
 413     return E_INVALIDARG;
 414   }
 415
 416   /* Sharing */
 417   switch (STGM_SHARE_MODE(dwMode))
 418   {
 419   case 0:
 420   case STGM_SHARE_DENY_NONE:
 421     dwShare = FILE_SHARE_READ|FILE_SHARE_WRITE;
 422     break;
 423   case STGM_SHARE_DENY_READ:
 424     dwShare = FILE_SHARE_WRITE;
 425     break;
 426   case STGM_SHARE_DENY_WRITE:
 427     dwShare = FILE_SHARE_READ;
 428     break;
 429   case STGM_SHARE_EXCLUSIVE:
 430     dwShare = 0;
 431     break;
 432   default:
 433     return E_INVALIDARG;
 434   }
 435
 436   switch(STGM_CREATE_MODE(dwMode))
 437   {
 438   case STGM_FAILIFTHERE:
 439     dwCreate = bCreate ? CREATE_NEW : OPEN_EXISTING;
 440     break;
 441   case STGM_CREATE:
 442     dwCreate = CREATE_ALWAYS;
 443     break;
 444   default:
 445     return E_INVALIDARG;
 446   }
 447
 448   /* Open HANDLE to file */
 449   hFile = CreateFileW(lpszPath, dwAccess, dwShare, NULL, dwCreate,
 450                       dwAttributes, 0);
 451
 452   if(hFile == INVALID_HANDLE_VALUE)
 453     return HRESULT_FROM_WIN32(GetLastError());
 454
 455   *lppStream = IStream_Create(lpszPath, hFile, dwMode);
 456
 457   if(!*lppStream)
 458   {
 459     CloseHandle(hFile);
 460     return E_OUTOFMEMORY;
 461   }
 462   return S_OK;
 463 }
 464
 465 /*************************************************************************
 466  * SHCreateStreamOnFileW   [SHLWAPI.@]
 467  *
 468  * See SHCreateStreamOnFileA.
 469  */
 470 HRESULT WINAPI SHCreateStreamOnFileW(LPCWSTR lpszPath, DWORD dwMode,
 471                                    IStream **lppStream)
 472 {
 473   TRACE("(%s,%d,%p)\n", debugstr_w(lpszPath), dwMode, lppStream);
 474
 475   if (!lpszPath || !lppStream)
 476     return E_INVALIDARG;
 477
 478   if ((dwMode & (STGM_CONVERT|STGM_DELETEONRELEASE|STGM_TRANSACTED)) != 0)
 479     return E_INVALIDARG;
 480
 481   return SHCreateStreamOnFileEx(lpszPath, dwMode, 0, FALSE, NULL, lppStream);
 482 }
 483
 484 /*************************************************************************
 485  * SHCreateStreamOnFileA   [SHLWAPI.@]
 486  *
 487  * Create a stream on a file.
 488  *
 489  * PARAMS
 490  *  lpszPath  [I] Path of file to create stream on
 491  *  dwMode    [I] Mode to create stream in
 492  *  lppStream [O] Destination for created IStream object
 493  *
 494  * RETURNS
 495  * Success: S_OK. lppStream contains the new IStream object
 496  * Failure: E_INVALIDARG if any parameter is invalid, or an HRESULT error code
 497  */
 498 HRESULT WINAPI SHCreateStreamOnFileA(LPCSTR lpszPath, DWORD dwMode,
 499                                      IStream **lppStream)
 500 {
 501   WCHAR szPath[MAX_PATH];
 502
 503   TRACE("(%s,%d,%p)\n", debugstr_a(lpszPath), dwMode, lppStream);
 504
 505   if (!lpszPath)
 506     return HRESULT_FROM_WIN32(ERROR_PATH_NOT_FOUND);
 507
 508   MultiByteToWideChar(CP_ACP, 0, lpszPath, -1, szPath, MAX_PATH);
 509   return SHCreateStreamOnFileW(szPath, dwMode, lppStream);
 510 }
 511
 512 /*************************************************************************
 513  * @       [SHLWAPI.184]
 514  *
 515  * Call IStream_Read() on a stream.
 516  *
 517  * PARAMS
 518  *  lpStream [I] IStream object
 519  *  lpvDest  [O] Destination for data read
 520  *  ulSize   [I] Size of data to read
 521  *
 522  * RETURNS
 523  *  Success: S_OK. ulSize bytes have been read from the stream into lpvDest.
 524  *  Failure: An HRESULT error code, or E_FAIL if the read succeeded but the
 525  *           number of bytes read does not match.
 526  */
 527 HRESULT WINAPI SHIStream_Read(IStream *lpStream, LPVOID lpvDest, ULONG ulSize)
 528 {
 529   ULONG ulRead;
 530   HRESULT hRet;
 531
 532   TRACE("(%p,%p,%d)\n", lpStream, lpvDest, ulSize);
 533
 534   hRet = IStream_Read(lpStream, lpvDest, ulSize, &ulRead);
 535
 536   if (SUCCEEDED(hRet) && ulRead != ulSize)
 537     hRet = E_FAIL;
 538   return hRet;
 539 }
 540
 541 /*************************************************************************
 542  * @       [SHLWAPI.166]
 543  *
 544  * Determine if a stream has 0 length.
 545  *
 546  * PARAMS
 547  *  lpStream [I] IStream object
 548  *
 549  * RETURNS
 550  *  TRUE:  If the stream has 0 length
 551  *  FALSE: Otherwise.
 552  */
 553 BOOL WINAPI SHIsEmptyStream(IStream *lpStream)
 554 {
 555   STATSTG statstg;
 556   BOOL bRet = TRUE;
 557
 558   TRACE("(%p)\n", lpStream);
 559
 560   memset(&statstg, 0, sizeof(statstg));
 561
 562   if(SUCCEEDED(IStream_Stat(lpStream, &statstg, 1)))
 563   {
 564     if(statstg.cbSize.QuadPart)
 565       bRet = FALSE; /* Non-Zero */
 566   }
 567   else
 568   {
 569     DWORD dwDummy;
 570
 571     /* Try to read from the stream */
 572     if(SUCCEEDED(SHIStream_Read(lpStream, &dwDummy, sizeof(dwDummy))))
 573     {
 574       LARGE_INTEGER zero;
 575       zero.QuadPart = 0;
 576
 577       IStream_Seek(lpStream, zero, 0, NULL);
 578       bRet = FALSE; /* Non-Zero */
 579     }
 580   }
 581   return bRet;
 582 }
 583
 584 /*************************************************************************
 585  * @       [SHLWAPI.212]
 586  *
 587  * Call IStream_Write() on a stream.
 588  *
 589  * PARAMS
 590  *  lpStream [I] IStream object
 591  *  lpvSrc   [I] Source for data to write
 592  *  ulSize   [I] Size of data
 593  *
 594  * RETURNS
 595  *  Success: S_OK. ulSize bytes have been written to the stream from lpvSrc.
 596  *  Failure: An HRESULT error code, or E_FAIL if the write succeeded but the
 597  *           number of bytes written does not match.
 598  */
 599 HRESULT WINAPI SHIStream_Write(IStream *lpStream, LPCVOID lpvSrc, ULONG ulSize)
 600 {
 601   ULONG ulWritten;
 602   HRESULT hRet;
 603
 604   TRACE("(%p,%p,%d)\n", lpStream, lpvSrc, ulSize);
 605
 606   hRet = IStream_Write(lpStream, lpvSrc, ulSize, &ulWritten);
 607
 608   if (SUCCEEDED(hRet) && ulWritten != ulSize)
 609     hRet = E_FAIL;
 610
 611   return hRet;
 612 }
 613
 614 /*************************************************************************
 615  * @       [SHLWAPI.213]
 616  *
 617  * Seek to the start of a stream.
 618  *
 619  * PARAMS
 620  *  lpStream [I] IStream object
 621  *
 622  * RETURNS
 623  *  Success: S_OK. The current position within the stream is updated
 624  *  Failure: An HRESULT error code.
 625  */
 626 HRESULT WINAPI IStream_Reset(IStream *lpStream)
 627 {
 628   LARGE_INTEGER zero;
 629   TRACE("(%p)\n", lpStream);
 630   zero.QuadPart = 0;
 631   return IStream_Seek(lpStream, zero, 0, NULL);
 632 }
 633
 634 /*************************************************************************
 635  * @       [SHLWAPI.214]
 636  *
 637  * Get the size of a stream.
 638  *
 639  * PARAMS
 640  *  lpStream [I] IStream object
 641  *  lpulSize [O] Destination for size
 642  *
 643  * RETURNS
 644  *  Success: S_OK. lpulSize contains the size of the stream.
 645  *  Failure: An HRESULT error code.
 646  */
 647 HRESULT WINAPI IStream_Size(IStream *lpStream, ULARGE_INTEGER* lpulSize)
 648 {
 649   STATSTG statstg;
 650   HRESULT hRet;
 651
 652   TRACE("(%p,%p)\n", lpStream, lpulSize);
 653
 654   memset(&statstg, 0, sizeof(statstg));
 655
 656   hRet = IStream_Stat(lpStream, &statstg, 1);
 657
 658   if (SUCCEEDED(hRet) && lpulSize)
 659     *lpulSize = statstg.cbSize;
 660   return hRet;
 661 }