Revert "Remove memcmp from MessagePackString. Fix #206."

This reverts commit 208c0c7 and a part of 23effe8.

Author: yfakariya

CHANGES.txt

@@ -621,9 +621,6 @@ Release 0.9.0 beta1 2016/09/24
 
 Release 0.9.0 beta2 2017/2/11
 
-  BREAKING CHANGES
-  * MessagePackObject comparison which have large binary data will be about 2x - 18x slower in .NET 3.5/4.5/4.6(other platforms will not be affected).
-
   NEW FEATURES
   * Users of serializer code generator API can specify TextWriter to output. This may improve tooling chain.
   * Users of serializer code generator API can suppress [DebuggerNonUserCode] attribute to enable debugger step in.
@@ -638,7 +635,6 @@ Release 0.9.0 beta2 2017/2/11
   * Fix extra field causes IndexOutOfBoundException when reflection based serializers are used. Issue #199
   * Fix some built-in serializers throws InvalidOperationException instead of SerializationException for type errors. Issue #204
   * Fix a combination of readonly members and collection members incorrect code generation when the type also have deserialization constructor. Issue #207.
-  * Fix Windows Native build error. Issue #206.
   * Fix built-in collection serializers such as List<T> serializer causes SecurityException when the program run in restricted environment like Silverlight. Issue #205.
   * Fix null items of complex type in List<T> or Dictionary<TKey, TValue> will not be deserialized as null. Issue #211. (from 0.8.1)
   * Fix types which implement IPackable and IUnpackable but do not have any members cannot be serialized. Issue #202

MsgPack.sln

@@ -43,6 +43,9 @@ EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MsgPack.Net45", "src\MsgPack.Net45\MsgPack.Net45.csproj", "{9C7B55A6-AF7F-4D26-AB5B-297B7FF25B6D}"
 EndProject
 Global
+	GlobalSection(Performance) = preSolution
+		HasPerformanceSessions = true
+	EndGlobalSection
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		CodeAnalysis|Any CPU = CodeAnalysis|Any CPU
 		CodeAnalysis|ARM = CodeAnalysis|ARM

src/MsgPack.Net35/MsgPack.Net35.csproj

@@ -1020,6 +1020,9 @@
     <Compile Include="..\MsgPack\UnpackingStreamReader.cs">
       <Link>UnpackingStreamReader.cs</Link>
     </Compile>
+    <Compile Include="..\MsgPack\UnsafeNativeMethods.cs">
+      <Link>UnsafeNativeMethods.cs</Link>
+    </Compile>
     <Compile Include="..\MsgPack\Validation.cs">
       <Link>Validation.cs</Link>
     </Compile>

src/MsgPack.Net45/MsgPack.Net45.csproj

@@ -1057,6 +1057,9 @@
     <Compile Include="..\MsgPack\UnpackingStreamReader.cs">
       <Link>UnpackingStreamReader.cs</Link>
     </Compile>
+    <Compile Include="..\MsgPack\UnsafeNativeMethods.cs">
+      <Link>UnsafeNativeMethods.cs</Link>
+    </Compile>
     <Compile Include="..\MsgPack\Validation.cs">
       <Link>Validation.cs</Link>
     </Compile>

src/MsgPack.Silverlight.5/MsgPack.Silverlight.5.csproj

@@ -56,8 +56,7 @@
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'CodeAnalysis|AnyCPU'">
     <OutputPath>bin\CodeAnalysis\</OutputPath>
     <DefineConstants>TRACE;SILVERLIGHT;CODE_ANALYSIS</DefineConstants>
-    <DocumentationFile>
-    </DocumentationFile>
+    <DocumentationFile></DocumentationFile>
     <Optimize>true</Optimize>
     <NoStdLib>true</NoStdLib>
     <DebugType>pdbonly</DebugType>
@@ -777,6 +776,9 @@
     <Compile Include="..\MsgPack\UnpackingStreamReader.cs">
       <Link>UnpackingStreamReader.cs</Link>
     </Compile>
+    <Compile Include="..\MsgPack\UnsafeNativeMethods.cs">
+      <Link>UnsafeNativeMethods.cs</Link>
+    </Compile>
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Serialization\LockRecursionPolicy.cs" />
     <Compile Include="Serialization\ReaderWriterLockSlim.cs" />

src/MsgPack.Xamarin.Android/MsgPack.Xamarin.Android.csproj

@@ -758,6 +758,9 @@
     <Compile Include="..\MsgPack\UnpackingStreamReader.cs">
       <Link>UnpackingStreamReader.cs</Link>
     </Compile>
+    <Compile Include="..\MsgPack\UnsafeNativeMethods.cs">
+      <Link>UnsafeNativeMethods.cs</Link>
+    </Compile>
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>

src/MsgPack.Xamarin.iOS/MsgPack.Xamarin.iOS.csproj

@@ -754,6 +754,9 @@
     <Compile Include="..\MsgPack\UnpackingStreamReader.cs">
       <Link>UnpackingStreamReader.cs</Link>
     </Compile>
+    <Compile Include="..\MsgPack\UnsafeNativeMethods.cs">
+      <Link>UnsafeNativeMethods.cs</Link>
+    </Compile>
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>

src/MsgPack/MessagePackString.cs

@@ -266,21 +266,30 @@ private static bool EqualsEncoded( MessagePackString left, MessagePackString rig
 				return false;
 			}
 
+#if !UNITY && !WINDOWS_PHONE && !NETFX_CORE
+			if ( _isFastEqualsDisabled == 0 )
+			{
+				try
+				{
+					return UnsafeFastEquals( left._encoded, right._encoded );
+				}
+				catch ( SecurityException )
+				{
+					Interlocked.Exchange( ref _isFastEqualsDisabled, 1 );
+				}
+				catch ( MemberAccessException )
+				{
+					Interlocked.Exchange( ref _isFastEqualsDisabled, 1 );
+				}
+			}
+#endif // if !UNITY && !WINDOWS_PHONE && !NETFX_CORE
+
 			return SlowEquals( left._encoded, right._encoded );
 		}
 
-		// It is 1.8x(not-aligned) - 11.1x (well-aligned) slower than memcmp, but this call is rare and it is acceptable in most cases.
-		// It is roughly equal to String.Equals(String).
 		private static bool SlowEquals( byte[] x, byte[] y )
 		{
-			if ( x.Length != y.Length )
-			{
-				return false;
-			}
-
-			// This looks naive, but loop expansion or unsafe code is not effect here (unsafe is more slower).
-
-			for ( var i = 0; i < x.Length; i++ )
+			for ( int i = 0; i < x.Length; i++ )
 			{
 				if ( x[ i ] != y[ i ] )
 				{
@@ -291,6 +300,44 @@ private static bool SlowEquals( byte[] x, byte[] y )
 			return true;
 		}
 
+#if !UNITY && !WINDOWS_PHONE && !NETFX_CORE
+#if SILVERLIGHT
+		private static int _isFastEqualsDisabled =
+			System.Windows.Application.Current.HasElevatedPermissions ? 0 : 1;
+#else
+		private static int _isFastEqualsDisabled;
+#endif // if SILVERLIGHT
+
+#if DEBUG
+		// for testing
+		internal static bool IsFastEqualsDisabled
+		{
+			get { return _isFastEqualsDisabled != 0; }
+		}
+#endif
+
+#if !NETFX_35 && !UNITY
+		[SecuritySafeCritical]
+#endif // !NETFX_35 && !UNITY
+		private static bool UnsafeFastEquals( byte[] x, byte[] y )
+		{
+#if DEBUG
+			Contract.Assert( x != null, "x != null" );
+			Contract.Assert( y != null, "y != null" );
+			Contract.Assert( 0 < x.Length, "0 < x.Length" );
+			Contract.Assert( x.Length == y.Length, "x.Length == y.Length" );
+#endif // if DEBUG
+			int result;
+			if ( !UnsafeNativeMethods.TryMemCmp( x, y, new UIntPtr( unchecked( ( uint )x.Length ) ), out result ) )
+			{
+				Interlocked.Exchange( ref _isFastEqualsDisabled, 1 );
+				return SlowEquals( x, y );
+			}
+
+			return result == 0;
+		}
+#endif // if !UNITY && !WINDOWS_PHONE && !NETFX_CORE
+
 #if !SILVERLIGHT && !NETSTANDARD1_1 && !NETSTANDARD1_3
 		[Serializable]
 #endif // !SILVERLIGHT && !NETSTANDARD1_1 && !NETSTANDARD1_3

src/MsgPack/MsgPack.csproj

@@ -541,6 +541,7 @@
     <Compile Include="UnpackingMode.cs" />
     <Compile Include="UnpackingStream.cs" />
     <Compile Include="UnpackingStreamReader.cs" />
+    <Compile Include="UnsafeNativeMethods.cs" />
     <Compile Include="Validation.cs" />
     <Compile Include="UnpackingResult.cs" />
     <Compile Include="Unpacker.cs" />

src/MsgPack/UnsafeNativeMethods.cs

@@ -0,0 +1,103 @@
+#region -- License Terms --
+//
+// MessagePack for CLI
+//
+// Copyright (C) 2010-2016 FUJIWARA, Yusuke
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+#endregion -- License Terms --
+
+using System;
+using System.Runtime.InteropServices;
+using System.Security;
+using System.Threading;
+
+namespace MsgPack
+{
+
+#if !SILVERLIGHT && !NETSTANDARD1_1 && !NETSTANDARD1_3
+	[SuppressUnmanagedCodeSecurity]
+#endif // !SILVERLIGHT && !NETSTANDARD1_1 && !NETSTANDARD1_3
+#if !NETFX_35
+	[SecurityCritical]
+#endif // !NETFX_35
+	internal static class UnsafeNativeMethods
+	{
+		private static int _libCAvailability = 0;
+		private const int _libCAvailability_Unknown = 0;
+		private const int _libCAvailability_MSVCRT = 1;
+		private const int _libCAvailability_LibC = 2;
+		private const int _libCAvailability_None = -1;
+
+#if NETFX_35
+		[System.Diagnostics.CodeAnalysis.SuppressMessage( "Microsoft.Security", "CA5122:PInvokesShouldNotBeSafeCriticalFxCopRule", Justification = "OK, this is SecurityCritical" )]
+#endif // NETFX_35
+		[DllImport( "msvcrt", CallingConvention = CallingConvention.Cdecl, EntryPoint = "memcmp", ExactSpelling = true, SetLastError = false )]
+		private static extern int memcmpVC( byte[] s1, byte[] s2, /*SIZE_T*/UIntPtr size );
+
+#if !NETFX_CORE
+		// libc is for non Windows environment.
+		// Note that libc caused compilation error on .NET Native, so the DllImport itself should not be included in the first time.
+#if NETFX_35
+		[System.Diagnostics.CodeAnalysis.SuppressMessage( "Microsoft.Security", "CA5122:PInvokesShouldNotBeSafeCriticalFxCopRule", Justification = "OK, this is SecurityCritical" )]
+#endif // NETFX_35
+		[DllImport( "libc", CallingConvention = CallingConvention.Cdecl, EntryPoint = "memcmp", ExactSpelling = true, SetLastError = false )]
+		private static extern int memcmpLibC( byte[] s1, byte[] s2, /*SIZE_T*/UIntPtr size );
+#endif // !NETFX_CORE
+
+		public static bool TryMemCmp( byte[] s1, byte[] s2, /*SIZE_T*/UIntPtr size, out int result )
+		{
+			if ( _libCAvailability < 0 )
+			{
+				result = 0;
+				return false;
+			}
+
+			if ( _libCAvailability <= _libCAvailability_MSVCRT )
+			{
+				try
+				{
+					result = memcmpVC( s1, s2, size );
+					return true;
+				}
+				catch ( DllNotFoundException )
+				{
+#if !NETFX_CORE
+					Interlocked.Exchange( ref _libCAvailability, _libCAvailability_LibC );
+#else
+					Interlocked.Exchange( ref _libCAvailability, _libCAvailability_None );
+#endif // !NETFX_CORE
+				}
+			}
+
+#if !NETFX_CORE
+			if ( _libCAvailability <= _libCAvailability_LibC )
+			{
+				try
+				{
+					result = memcmpLibC( s1, s2, size );
+					return true;
+				}
+				catch ( DllNotFoundException )
+				{
+					Interlocked.Exchange( ref _libCAvailability, _libCAvailability_None );
+				}
+			}
+#endif // !NETFX_CORE
+
+			result = 0;
+			return false;
+		}
+	}
+}