Simplify AsnDecoder.ReverseBitsPerByte (#75301)

dotnet · Sep 9, 2022 · e380cab · e380cab
1 parent 253aea6
commit e380cab
Showing 1 changed file with 1 addition and 10 deletions.
diff --git a/src/libraries/System.Formats.Asn1/src/System/Formats/Asn1/AsnDecoder.NamedBitList.cs b/src/libraries/System.Formats.Asn1/src/System/Formats/Asn1/AsnDecoder.NamedBitList.cs
@@ -394,16 +394,7 @@ internal static void ReverseBitsPerByte(Span<byte> value)
         {
             for (int byteIdx = 0; byteIdx < value.Length; byteIdx++)
             {
-                byte cur = value[byteIdx];
-                byte mask = 0b1000_0000;
-                byte next = 0;
-
-                for (; cur != 0; cur >>= 1, mask >>= 1)
-                {
-                    next |= (byte)((cur & 1) * mask);
-                }
-
-                value[byteIdx] = next;
+                value[byteIdx] = (byte)((value[byteIdx] * 0x0202020202ul & 0x010884422010ul) % 1023);
             }
         }
     }