Changeset 3167 for trunk/src/ole32/stg_stream.cpp

Timestamp:

Mar 19, 2000, 4:35:32 PM (25 years ago)

Author:

davidr

Message:

Ported changes from wine/corel sources

File:

• trunk/src/ole32/stg_stream.cpp (modified) (8 diffs)

trunk/src/ole32/stg_stream.cpp

@@ -1 @@
-/* $Id: stg_stream.cpp,v 1.1 1999-09-24 21:49:44 davidr Exp $ */
+/* $Id: stg_stream.cpp,v 1.2 2000-03-19 15:33:07 davidr Exp $ */
 /* 
  * Compound Storage (32 bit version)
@@ -65 +65 @@
 StgStreamImpl* StgStreamImpl_Construct(
                 StorageBaseImpl* parentStorage,
+                DWORD            grfMode,
                 ULONG              ownerProperty)
 {
@@ -76 +77 @@
      * Set-up the virtual function table and reference count.
      */
-    newStream->lpvtbl = &StgStreamImpl_Vtbl;
+    ICOM_VTBL(newStream) = &StgStreamImpl_Vtbl;
     newStream->ref    = 0;
     
@@ -86 +87 @@
     IStorage_AddRef((IStorage*)newStream->parentStorage);
     
+    newStream->grfMode = grfMode;    
     newStream->ownerProperty = ownerProperty;
     
@@ -431 +433 @@
   *pcbWritten = 0;
 
+  /*
+   * Do we have permission to write to this stream?
+   */
+  if (!(This->grfMode & (STGM_WRITE | STGM_READWRITE)))
+    return STG_E_ACCESSDENIED;
+
   if (cb == 0)
   {
@@ -533 +541 @@
   }
 
-  /*
-   * We don't support files with offsets of 64 bits.
-   */
-  assert(dlibMove.HighPart == 0);
-
-  /*
-   * Check if we end-up before the beginning of the file. That should trigger an
-   * error.
-   */
-  if ( (dlibMove.LowPart<0) && (plibNewPosition->LowPart < (ULONG)(-dlibMove.LowPart)) )
-  {
+#if SIZEOF_LONG_LONG >= 8
+  plibNewPosition->QuadPart += dlibMove.QuadPart;
+#else
+  /*
+   * do some multiword arithmetic:
+   *    treat HighPart as a signed value
+   *    treat LowPart as unsigned
+   *  NOTE: this stuff is two's complement specific!
+   */
+  if (dlibMove.HighPart < 0) { /* dlibMove is < 0 */
+      /* calculate the absolute value of dlibMove ... */
+      dlibMove.HighPart = -dlibMove.HighPart;
+      dlibMove.LowPart ^= -1;
+      /* ... and subtract with carry */
+      if (dlibMove.LowPart > plibNewPosition->LowPart) {
+          /* carry needed, This accounts for any underflows at [1]*/
+          plibNewPosition->HighPart -= 1; 
+      }
+      plibNewPosition->LowPart -= dlibMove.LowPart; /* [1] */
+      plibNewPosition->HighPart -= dlibMove.HighPart; 
+  } else {
+      /* add directly */
+      int initialLowPart = plibNewPosition->LowPart;
+      plibNewPosition->LowPart += dlibMove.LowPart;
+      if((plibNewPosition->LowPart < initialLowPart) ||
+         (plibNewPosition->LowPart < dlibMove.LowPart)) {
+          /* LowPart has rolled over => add the carry digit to HighPart */
+          plibNewPosition->HighPart++;
+      }
+      plibNewPosition->HighPart += dlibMove.HighPart; 
+  }
+  /*
+   * Check if we end-up before the beginning of the file. That should 
+   * trigger an error.
+   */
+  if (plibNewPosition->HighPart < 0) {
+      return STG_E_INVALIDPOINTER;
+  }
+
     /*
-     * I don't know what error to send there.
+   * We currently don't support files with offsets of >32 bits.  
+   * Note that we have checked for a negative offset already
      */
-    return E_FAIL;
-  }
-
-  /*
-   * Move the actual file pointer
-   * If the file pointer ends-up after the end of the stream, the next Write operation will
-   * make the file larger. This is how it is documented.
-   */
-  plibNewPosition->LowPart += dlibMove.LowPart;
+  assert(plibNewPosition->HighPart <= 0);
+
+#endif
+
+  /*
+   * tell the caller what we calculated
+   */
   This->currentPosition = *plibNewPosition;
  
@@ -587 +622 @@
     return STG_E_INVALIDFUNCTION;
   
+  /*
+   * Do we have permission?
+   */
+  if (!(This->grfMode & (STGM_WRITE | STGM_READWRITE)))
+    return STG_E_ACCESSDENIED;
+
   if (This->streamSize.LowPart == libNewSize.LowPart)
     return S_OK;
@@ -828 +869 @@
                                      grfStatFlag);
     
+    pstatstg->grfMode = This->grfMode;
+
     return S_OK;
   }