[aandrejevic] 59339: [NTVDM] Fix more bugs in DosResizeMemory().

Author: aandrejevic
Date: Tue Jun 25 17:18:34 2013
New Revision: 59339

URL: http://svn.reactos.org/svn/reactos?rev=59339&view=rev
Log:
[NTVDM]
Fix more bugs in DosResizeMemory().

Modified:
    branches/ntvdm/subsystems/ntvdm/dos.c
    branches/ntvdm/subsystems/ntvdm/ntvdm.h

Modified: branches/ntvdm/subsystems/ntvdm/dos.c
URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/dos.c?rev...
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/dos.c	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/dos.c	[iso-8859-1] Tue Jun 25 17:18:34 2013
@@ -152,31 +152,41 @@
     return Result + 1;
 }

-WORD DosResizeMemory(WORD BlockData, WORD NewSize)
-{
+BOOLEAN DosResizeMemory(WORD BlockData, WORD NewSize, WORD *MaxAvailable)
+{
+    BOOLEAN Success = TRUE;
     WORD Segment = BlockData - 1, ReturnSize = 0, NextSegment;
     PDOS_MCB Mcb = SEGMENT_TO_MCB(Segment), NextMcb;

/* Make sure this is a valid, allocated block */
     if ((Mcb->BlockType != 'M' && Mcb->BlockType != 'Z') || Mcb->OwnerPsp == 0)
     {
-        return 0;
-    }
-
-    /* Check if need to expand or contract the block */
+        Success = FALSE;
+        goto Done;
+    }
+
+    ReturnSize = Mcb->Size;
+
+    /* Check if we need to expand or contract the block */
     if (NewSize > Mcb->Size)
     {
         /* We can't expand the last block */
-        if (Mcb->BlockType != 'M') return Mcb->Size;
-
-        ReturnSize = Mcb->Size;
-        
+        if (Mcb->BlockType != 'M')
+        {
+            Success = FALSE;
+            goto Done;
+        }
+
         /* Get the pointer and segment of the next MCB */
         NextSegment = Segment + Mcb->Size + 1;
         NextMcb = SEGMENT_TO_MCB(NextSegment);

/* Make sure the next segment is free */
-        if (NextMcb->OwnerPsp != 0) return Mcb->Size;
+        if (NextMcb->OwnerPsp != 0)
+        {
+            Success = FALSE;
+            goto Done;
+        }

/* Combine this free block with adjoining free blocks */
         DosCombineFreeBlocks(NextSegment);
@@ -220,7 +230,15 @@
         Mcb->Size = NewSize;
     }

-    return ReturnSize;
+Done:
+    /* Check if the operation failed */
+    if (!Success)
+    {
+        /* Return the maximum possible size */
+        if (MaxAvailable) *MaxAvailable = ReturnSize;
+    }
+    
+    return Success;
 }

BOOLEAN DosFreeMemory(WORD BlockData)
@@ -785,14 +803,17 @@
         /* Resize Memory Block */
         case 0x4A:
         {
-            WORD Size = DosResizeMemory(ExtSegment, LOWORD(Ebx));
-
-            if (Size != 0)
-            {
+            WORD Size;
+
+            if (DosResizeMemory(ExtSegment, LOWORD(Ebx), &Size))
+            {
+                EmulatorClearFlag(EMULATOR_FLAG_CF);
+            }
+            else
+            {
+                EmulatorSetFlag(EMULATOR_FLAG_CF);
                 EmulatorSetRegister(EMULATOR_REG_BX, Size);
-                EmulatorClearFlag(EMULATOR_FLAG_CF);
-            }
-            else EmulatorSetFlag(EMULATOR_FLAG_CF);
+            }

break;
         }

Modified: branches/ntvdm/subsystems/ntvdm/ntvdm.h
URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/ntvdm.h?r...
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/ntvdm.h	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/ntvdm.h	[iso-8859-1] Tue Jun 25 17:18:34 2013
@@ -208,7 +208,7 @@
 BOOLEAN DosInitialize();
 WORD DosAllocateMemory(WORD Size, WORD *MaxAvailable);
 BOOLEAN DosFreeMemory(WORD BlockData);
-WORD DosResizeMemory(WORD BlockData, WORD NewSize);
+BOOLEAN DosResizeMemory(WORD BlockData, WORD NewSize, WORD *MaxAvailable);
 BOOLEAN DosCreateProcess(LPCSTR CommandLine, WORD EnvBlock);
 VOID DosInt20h(WORD CodeSegment);
 VOID DosInt21h(WORD CodeSegment);