[tkreuzer] 56793: [RTL] Fix a bug in RtlNumberOfSetBits

Author: tkreuzer
Date: Sun Jun 24 12:51:27 2012
New Revision: 56793

URL: http://svn.reactos.org/svn/reactos?rev=56793&view=rev
Log:
[RTL]
Fix a bug in RtlNumberOfSetBits

Modified:
    trunk/reactos/lib/rtl/bitmap.c

Modified: trunk/reactos/lib/rtl/bitmap.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/lib/rtl/bitmap.c?rev=56793…
==============================================================================
--- trunk/reactos/lib/rtl/bitmap.c [iso-8859-1] (original)
+++ trunk/reactos/lib/rtl/bitmap.c [iso-8859-1] Sun Jun 24 12:51:27 2012
@@ -410,16 +410,18 @@
     IN PRTL_BITMAP BitMapHeader)
 {
     PUCHAR Byte, MaxByte;
-    ULONG BitCount = 0;
+    ULONG BitCount = 0, Shift;
 
     Byte = (PUCHAR)BitMapHeader->Buffer;
-    MaxByte = Byte + (BitMapHeader->SizeOfBitMap + 7) / 8;
-
-    do
+    MaxByte = Byte + BitMapHeader->SizeOfBitMap / 8;
+
+    while (Byte < MaxByte);
     {
         BitCount += BitCountTable[*Byte++];
     }
-    while (Byte <= MaxByte);
+
+    Shift = 8 - (BitMapHeader->SizeOfBitMap & 7);
+    BitCount += BitCountTable[(*Byte) << Shift];
 
     return BitCount;
 }