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Use Span.IndexOf rather than Contains (#1638) 

- Remove Contains method and use IndexOf (which is already vectorized) to look for CR in header values.
This commit is contained in:
Ben Adams 2017-04-09 07:45:26 +01:00 committed by David Fowler
parent d92c55dbfc
commit fb22629da6
1 changed files with 11 additions and 49 deletions
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60
src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/HttpParser.cs
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@ -1,7 +1,6 @@
// 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.
using System.Numerics;
using System.Runtime.CompilerServices;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
using Microsoft.AspNetCore.Server.Kestrel.Internal.System;
@ -379,13 +378,14 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
}
// Check for CR in value
var i = valueStart + 1;
if (Contains(headerLine + i, valueEnd - i, ByteCR))
var valueBuffer = new Span<byte>(headerLine + valueStart, valueEnd - valueStart + 1);
if (valueBuffer.IndexOf(ByteCR) >= 0)
{
RejectRequestHeader(headerLine, length);
}
// Ignore end whitespace
var lengthChanged = false;
for (; valueEnd >= valueStart; valueEnd--)
{
var ch = headerLine[valueEnd];
@ -393,50 +393,21 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
{
break;
}
lengthChanged = true;
}
if (lengthChanged)
{
// Length changed
valueBuffer = new Span<byte>(headerLine + valueStart, valueEnd - valueStart + 1);
}
var nameBuffer = new Span<byte>(headerLine, nameEnd);
var valueBuffer = new Span<byte>(headerLine + valueStart, valueEnd - valueStart + 1);
handler.OnHeader(nameBuffer, valueBuffer);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static unsafe bool Contains(byte* searchSpace, int length, byte value)
{
var i = 0;
if (Vector.IsHardwareAccelerated)
{
// Check Vector lengths
if (length - Vector<byte>.Count >= i)
{
var vValue = GetVector(value);
do
{
if (!Vector<byte>.Zero.Equals(Vector.Equals(vValue, Unsafe.Read<Vector<byte>>(searchSpace + i))))
{
goto found;
}
i += Vector<byte>.Count;
} while (length - Vector<byte>.Count >= i);
}
}
// Check remaining for CR
for (; i <= length; i++)
{
var ch = searchSpace[i];
if (ch == value)
{
goto found;
}
}
return false;
found:
return true;
}
[MethodImpl(MethodImplOptions.NoInlining)]
private static bool TryGetNewLine(ref ReadableBuffer buffer, out ReadCursor found)
{
@ -524,14 +495,5 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
public void Reset()
{
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static Vector<byte> GetVector(byte vectorByte)
{
// Vector<byte> .ctor doesn't become an intrinsic due to detection issue
// However this does cause it to become an intrinsic (with additional multiply and reg->reg copy)
// https://github.com/dotnet/coreclr/issues/7459#issuecomment-253965670
return Vector.AsVectorByte(new Vector<uint>(vectorByte * 0x01010101u));
}
}
}