From 8bf2c814d64c8475415c1c9ba81ffaae84039275 Mon Sep 17 00:00:00 2001
From: Ben Adams <thundercat@illyriad.co.uk>
Date: Wed, 7 Oct 2015 12:23:20 -0400
Subject: [PATCH] Add BitCount LongExtensions

---
 .../Http/FrameHeaders.Generated.cs            | 364 +-----------------
 .../Infrastructure/LongExtensions.cs          |  18 +
 .../KnownHeaders.cs                           |   1 +
 3 files changed, 22 insertions(+), 361 deletions(-)
 create mode 100644 src/Microsoft.AspNet.Server.Kestrel/Infrastructure/LongExtensions.cs

diff --git a/src/Microsoft.AspNet.Server.Kestrel/Http/FrameHeaders.Generated.cs b/src/Microsoft.AspNet.Server.Kestrel/Http/FrameHeaders.Generated.cs
index 9666fad29b..5ca0e5fc12 100644
--- a/src/Microsoft.AspNet.Server.Kestrel/Http/FrameHeaders.Generated.cs
+++ b/src/Microsoft.AspNet.Server.Kestrel/Http/FrameHeaders.Generated.cs
@@ -1,6 +1,7 @@
 
 using System;
 using System.Collections.Generic;
+using Microsoft.AspNet.Server.Kestrel.Extensions;
 using Microsoft.Extensions.Primitives;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http 
@@ -589,214 +590,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
 
         protected override int GetCountFast()
         {
-            var count = MaybeUnknown?.Count ?? 0;
-            
-                if (((_bits & 1L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 2L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 4L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 8L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 16L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 32L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 64L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 128L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 256L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 512L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 1024L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 2048L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 4096L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 8192L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 16384L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 32768L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 65536L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 131072L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 262144L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 524288L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 1048576L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 2097152L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 4194304L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 8388608L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 16777216L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 33554432L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 67108864L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 134217728L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 268435456L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 536870912L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 1073741824L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 2147483648L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 4294967296L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 8589934592L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 17179869184L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 34359738368L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 68719476736L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 137438953472L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 274877906944L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 549755813888L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 1099511627776L) != 0)) 
-                {
-                    ++count;
-                }
-            
-            return count;
+            return _bits.BitCount() + (MaybeUnknown?.Count ?? 0);
         }
 
         protected override StringValues GetValueFast(string key)
@@ -5623,159 +5417,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
 
         protected override int GetCountFast()
         {
-            var count = MaybeUnknown?.Count ?? 0;
-            
-                if (((_bits & 1L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 2L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 4L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 8L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 16L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 32L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 64L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 128L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 256L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 512L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 1024L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 2048L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 4096L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 8192L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 16384L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 32768L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 65536L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 131072L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 262144L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 524288L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 1048576L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 2097152L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 4194304L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 8388608L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 16777216L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 33554432L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 67108864L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 134217728L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 268435456L) != 0)) 
-                {
-                    ++count;
-                }
-            
-                if (((_bits & 536870912L) != 0)) 
-                {
-                    ++count;
-                }
-            
-            return count;
+            return _bits.BitCount() + (MaybeUnknown?.Count ?? 0);
         }
 
         protected override StringValues GetValueFast(string key)
diff --git a/src/Microsoft.AspNet.Server.Kestrel/Infrastructure/LongExtensions.cs b/src/Microsoft.AspNet.Server.Kestrel/Infrastructure/LongExtensions.cs
new file mode 100644
index 0000000000..0ac6a718d4
--- /dev/null
+++ b/src/Microsoft.AspNet.Server.Kestrel/Infrastructure/LongExtensions.cs
@@ -0,0 +1,18 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNet.Server.Kestrel.Extensions
+{
+    public static class LongExtensions
+    {
+        public static int BitCount(this long value)
+        {
+            // Parallel bit count for a 64-bit integer
+            var v = (ulong)value;
+            v = v - ((v >> 1) & 0x5555555555555555);
+            v = (v & 0x3333333333333333) + ((v >> 2) & 0x3333333333333333);
+            v = (v + (v >> 4) & 0x0f0f0f0f0f0f0f0f);
+            return (int)((v * 0x0101010101010101) >> 56);
+        }
+    }
+}
diff --git a/tools/Microsoft.AspNet.Server.Kestrel.GeneratedCode/KnownHeaders.cs b/tools/Microsoft.AspNet.Server.Kestrel.GeneratedCode/KnownHeaders.cs
index 0fc30fa0de..6dbad61a7c 100644
--- a/tools/Microsoft.AspNet.Server.Kestrel.GeneratedCode/KnownHeaders.cs
+++ b/tools/Microsoft.AspNet.Server.Kestrel.GeneratedCode/KnownHeaders.cs
@@ -167,6 +167,7 @@ namespace Microsoft.AspNet.Server.Kestrel.GeneratedCode
             return $@"
 using System;
 using System.Collections.Generic;
+using Microsoft.AspNet.Server.Kestrel.Extensions;
 using Microsoft.Extensions.Primitives;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http