* Sync up to trunk head (r64921).

[reactos.git] / lib / rtl / bitmap.c

diff --git a/lib/rtl/bitmap.c b/lib/rtl/bitmap.c
index b009355..378c94c 100644 (file)
--- a/lib/rtl/bitmap.c
+++ b/lib/rtl/bitmap.c
@@ -30,6 +30,9 @@ typedef ULONG64 BITMAP_BUFFER, *PBITMAP_BUFFER;
 #undef BitScanForward
 #define BitScanForward(Index, Mask) \
     do { unsigned long tmp; BitScanForward64(&tmp, Mask); *Index = tmp; } while (0)
+#undef BitScanReverse
+#define BitScanReverse(Index, Mask) \
+    do { unsigned long tmp; BitScanReverse64(&tmp, Mask); *Index = tmp; } while (0)
 #define RtlFillMemoryUlong RtlFillMemoryUlonglong
 
 #define RtlInitializeBitMap RtlInitializeBitMap64
@@ -101,6 +104,11 @@ RtlpGetLengthOfRunClear(
     BITMAP_INDEX Value, BitPos, Length;
     PBITMAP_BUFFER Buffer, MaxBuffer;
 
+    /* If we are already at the end, the length of the run is zero */
+    ASSERT(StartingIndex <= BitMapHeader->SizeOfBitMap);
+    if (StartingIndex >= BitMapHeader->SizeOfBitMap)
+        return 0;
+
     /* Calculate positions */
     Buffer = BitMapHeader->Buffer + StartingIndex / _BITCOUNT;
     BitPos = StartingIndex & (_BITCOUNT - 1);
@@ -150,6 +158,11 @@ RtlpGetLengthOfRunSet(
     BITMAP_INDEX InvValue, BitPos, Length;
     PBITMAP_BUFFER Buffer, MaxBuffer;
 
+    /* If we are already at the end, the length of the run is zero */
+    ASSERT(StartingIndex <= BitMapHeader->SizeOfBitMap);
+    if (StartingIndex >= BitMapHeader->SizeOfBitMap)
+        return 0;
+
     /* Calculate positions */
     Buffer = BitMapHeader->Buffer + StartingIndex / _BITCOUNT;
     BitPos = StartingIndex & (_BITCOUNT - 1);
@@ -349,8 +362,11 @@ RtlClearBits(
 
     /* Clear what's left */
     NumberToClear &= (_BITCOUNT - 1);
-    Mask = MAXINDEX << NumberToClear;
-    *Buffer &= Mask;
+    if (NumberToClear != 0)
+    {
+        Mask = MAXINDEX << NumberToClear;
+        *Buffer &= Mask;
+    }
 }
 
 VOID
@@ -406,8 +422,11 @@ RtlSetBits(
 
     /* Set what's left */
     NumberToSet &= (_BITCOUNT - 1);
-    Mask = MAXINDEX << NumberToSet;
-    *Buffer |= ~Mask;
+    if (NumberToSet != 0)
+    {
+        Mask = MAXINDEX << NumberToSet;
+        *Buffer |= ~Mask;
+    }
 }
 
 BOOLEAN
@@ -467,8 +486,11 @@ RtlNumberOfSetBits(
         BitCount += BitCountTable[*Byte++];
     }
 
-    Shift = 8 - (BitMapHeader->SizeOfBitMap & 7);
-    BitCount += BitCountTable[((*Byte) << Shift) & 0xFF];
+    if (BitMapHeader->SizeOfBitMap & 7)
+    {
+        Shift = 8 - (BitMapHeader->SizeOfBitMap & 7);
+        BitCount += BitCountTable[((*Byte) << Shift) & 0xFF];
+    }
 
     return BitCount;
 }
@@ -721,7 +743,7 @@ RtlFindFirstRunClear(
     return RtlFindNextForwardRunClear(BitMapHeader, 0, StartingIndex);
 }
 
-ULONG
+BITMAP_INDEX
 NTAPI
 RtlFindLastBackwardRunClear(
     _In_ PRTL_BITMAP BitMapHeader,
@@ -758,7 +780,7 @@ RtlFindLastBackwardRunClear(
     BitScanReverse(&BitPos, InvValue);
 
     /* Calculate last bit position */
-    FromIndex = (Buffer + 1 - BitMapHeader->Buffer) * _BITCOUNT + BitPos;
+    FromIndex = (BITMAP_INDEX)((Buffer + 1 - BitMapHeader->Buffer) * _BITCOUNT + BitPos);
 
     Value = ~InvValue << ((_BITCOUNT - 1) - BitPos) >> ((_BITCOUNT - 1) - BitPos);
 
@@ -774,7 +796,7 @@ RtlFindLastBackwardRunClear(
         BitScanReverse(&BitPos, Value);
 
         /* Calculate Starting Index */
-        *StartingRunIndex = (Buffer + 1 - BitMapHeader->Buffer) * _BITCOUNT + BitPos + 1;
+        *StartingRunIndex = (BITMAP_INDEX)((Buffer + 1 - BitMapHeader->Buffer) * _BITCOUNT + BitPos + 1);
     }
     else
     {
@@ -783,7 +805,7 @@ RtlFindLastBackwardRunClear(
     }
 
     /* Return length of the run */
-    return FromIndex - *StartingRunIndex;
+    return (FromIndex - *StartingRunIndex);
 }