[NTVDM]:

- Use a static buffer for read or writes of "few" bytes (and allocate one for larger operations).
- Writes of zero length, in DOS, truncates or extends the file to the current position of the file pointer. This fixes some "corruption" in some files (so far, only .INI files) in Windows 3.11 installation.

svn path=/trunk/; revision=68604

diff --git a/reactos/subsystems/mvdm/ntvdm/dos/dos32krnl/dosfiles.c b/reactos/subsystems/mvdm/ntvdm/dos/dos32krnl/dosfiles.c
index c7252fa..8439161 100644 (file)
--- a/reactos/subsystems/mvdm/ntvdm/dos/dos32krnl/dosfiles.c
+++ b/reactos/subsystems/mvdm/ntvdm/dos/dos32krnl/dosfiles.c
@@ -676,6 +676,7 @@ WORD DosReadFile(WORD FileHandle,
 {
     WORD Result = ERROR_SUCCESS;
     PDOS_FILE_DESCRIPTOR Descriptor = DosGetHandleFileDescriptor(FileHandle);
+    BYTE StaticBuffer[8192];
 
     DPRINT("DosReadFile: FileHandle 0x%04X, Count 0x%04X\n", FileHandle, Count);
 
@@ -697,10 +698,19 @@ WORD DosReadFile(WORD FileHandle,
     else
     {
         DWORD BytesRead32 = 0;
-        LPVOID LocalBuffer = RtlAllocateHeap(RtlGetProcessHeap(), 0, Count);
-        ASSERT(LocalBuffer != NULL);
+        LPVOID LocalBuffer;
 
-        /* Read the file */
+        if (Count <= sizeof(StaticBuffer))
+        {
+            LocalBuffer = StaticBuffer;
+        }
+        else
+        {
+            LocalBuffer = RtlAllocateHeap(RtlGetProcessHeap(), 0, Count);
+            ASSERT(LocalBuffer != NULL);
+        }
+
+        /* Read from the file */
         if (ReadFile(Descriptor->Win32Handle, LocalBuffer, Count, &BytesRead32, NULL))
         {
             /* Write to the memory */
@@ -710,7 +720,7 @@ WORD DosReadFile(WORD FileHandle,
                                 LOWORD(BytesRead32));
 
             /* Update the position */
-            Descriptor->Position += BytesRead32;
+            Descriptor->Position += BytesRead32; // or LOWORD(BytesRead32); ?
         }
         else
         {
@@ -720,7 +730,9 @@ WORD DosReadFile(WORD FileHandle,
 
         /* The number of bytes read is always 16-bit */
         *BytesRead = LOWORD(BytesRead32);
-        RtlFreeHeap(RtlGetProcessHeap(), 0, LocalBuffer);
+
+        if (LocalBuffer != StaticBuffer)
+            RtlFreeHeap(RtlGetProcessHeap(), 0, LocalBuffer);
     }
 
     /* Return the error code */
@@ -734,6 +746,7 @@ WORD DosWriteFile(WORD FileHandle,
 {
     WORD Result = ERROR_SUCCESS;
     PDOS_FILE_DESCRIPTOR Descriptor = DosGetHandleFileDescriptor(FileHandle);
+    BYTE StaticBuffer[8192];
 
     DPRINT("DosWriteFile: FileHandle 0x%04X, Count 0x%04X\n", FileHandle, Count);
 
@@ -755,21 +768,44 @@ WORD DosWriteFile(WORD FileHandle,
     else
     {
         DWORD BytesWritten32 = 0;
-        LPVOID LocalBuffer = RtlAllocateHeap(RtlGetProcessHeap(), 0, Count);
-        ASSERT(LocalBuffer != NULL);
+        LPVOID LocalBuffer;
+
+        /*
+         * Writing zero bytes truncates or extends the file
+         * to the current position of the file pointer.
+         */
+        if (Count == 0)
+        {
+            if (!SetEndOfFile(Descriptor->Win32Handle))
+            {
+                /* Store the error code */
+                Result = (WORD)GetLastError();
+            }
+            *BytesWritten = 0;
+            return Result;
+        }
+
+        if (Count <= sizeof(StaticBuffer))
+        {
+            LocalBuffer = StaticBuffer;
+        }
+        else
+        {
+            LocalBuffer = RtlAllocateHeap(RtlGetProcessHeap(), 0, Count);
+            ASSERT(LocalBuffer != NULL);
+        }
 
         /* Read from the memory */
         EmulatorReadMemory(&EmulatorContext,
-                           TO_LINEAR(HIWORD(Buffer),
-                           LOWORD(Buffer)),
+                           TO_LINEAR(HIWORD(Buffer), LOWORD(Buffer)),
                            LocalBuffer,
                            Count);
 
-        /* Write the file */
+        /* Write to the file */
         if (WriteFile(Descriptor->Win32Handle, LocalBuffer, Count, &BytesWritten32, NULL))
         {
             /* Update the position and size */
-            Descriptor->Position += BytesWritten32;
+            Descriptor->Position += BytesWritten32; // or LOWORD(BytesWritten32); ?
             if (Descriptor->Position > Descriptor->Size) Descriptor->Size = Descriptor->Position;
         }
         else
@@ -780,7 +816,9 @@ WORD DosWriteFile(WORD FileHandle,
 
         /* The number of bytes written is always 16-bit */
         *BytesWritten = LOWORD(BytesWritten32);
-        RtlFreeHeap(RtlGetProcessHeap(), 0, LocalBuffer);
+
+        if (LocalBuffer != StaticBuffer)
+            RtlFreeHeap(RtlGetProcessHeap(), 0, LocalBuffer);
     }
 
     /* Return the error code */
@@ -797,9 +835,7 @@ WORD DosSeekFile(WORD FileHandle,
     PDOS_FILE_DESCRIPTOR Descriptor = DosGetHandleFileDescriptor(FileHandle);
 
     DPRINT("DosSeekFile: FileHandle 0x%04X, Offset 0x%08X, Origin 0x%02X\n",
-           FileHandle,
-           Offset,
-           Origin);
+           FileHandle, Offset, Origin);
 
     if (Descriptor == NULL)
     {
@@ -950,11 +986,10 @@ BOOLEAN DosDeviceIoControl(WORD FileHandle, BYTE ControlCode, DWORD Buffer, PWOR
         {
             // TODO: NOT IMPLEMENTED
             UNIMPLEMENTED;
-
             return FALSE;
         }
 
-        /* Read From Device I/O Control Channel */
+        /* Read from Device I/O Control Channel */
         case 0x02:
         {
             if (Node == NULL || !(Node->DeviceAttributes & DOS_DEVATTR_IOCTL))
@@ -974,7 +1009,7 @@ BOOLEAN DosDeviceIoControl(WORD FileHandle, BYTE ControlCode, DWORD Buffer, PWOR
             return TRUE;
         }
 
-        /* Write To Device I/O Control Channel */
+        /* Write to Device I/O Control Channel */
         case 0x03:
         {
             if (Node == NULL || !(Node->DeviceAttributes & DOS_DEVATTR_IOCTL))
@@ -1071,5 +1106,4 @@ BOOLEAN DosDeviceIoControl(WORD FileHandle, BYTE ControlCode, DWORD Buffer, PWOR
     }
 }
 
-
 /* EOF */