Imported Upstream version 5.16.0.100

Former-commit-id: 38faa55fb9669e35e7d8448b15c25dc447f25767

external/corefx/src/System.Text.Encoding.CodePages/ref/System.Text.Encoding.CodePages.cs

@@ -5,12 +5,13 @@
 // Changes to this file must follow the http://aka.ms/api-review process.
 // ------------------------------------------------------------------------------
 
-
 namespace System.Text
 {
-    public sealed partial class CodePagesEncodingProvider
+    public sealed partial class CodePagesEncodingProvider : System.Text.EncodingProvider
     {
         internal CodePagesEncodingProvider() { }
         public static System.Text.EncodingProvider Instance { get { throw null; } }
+        public override System.Text.Encoding GetEncoding(int codepage) { throw null; }
+        public override System.Text.Encoding GetEncoding(string name) { throw null; }
     }
 }

external/corefx/src/System.Text.Encoding.CodePages/src/System.Text.Encoding.CodePages.csproj

@@ -73,6 +73,7 @@
     <Reference Include="System.Runtime.Extensions" />
     <Reference Include="System.Runtime.InteropServices" />
     <Reference Include="System.Threading" />
+    <Reference Include="System.Runtime.CompilerServices.Unsafe" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
   <!-- Generator for code mapping table, target to invoke is GenerateEncodingSource -->

external/corefx/src/System.Text.Encoding.CodePages/src/System/Text/BaseCodePageEncoding.cs

@@ -82,7 +82,7 @@ namespace System.Text
             throw new PlatformNotSupportedException();
         }
 
-        // Just a helper as we cannot use 'this' when calling 'base(...)' 
+        // Just a helper as we cannot use 'this' when calling 'base(...)'
         private void SetFallbackEncoding()
         {
             (EncoderFallback as InternalEncoderBestFitFallback).encoding = this;
@@ -330,8 +330,8 @@ namespace System.Text
             return arrayBytesBestFit;
         }
 
-        // During the AppDomain shutdown the Encoding class may have already finalized, making the memory section 
-        // invalid. We detect that by validating the memory section handle then re-initializing the memory 
+        // During the AppDomain shutdown the Encoding class may have already finalized, making the memory section
+        // invalid. We detect that by validating the memory section handle then re-initializing the memory
         // section by calling LoadManagedCodePage() method and eventually the mapped file handle and
         // the memory section pointer will get finalized one more time.
         internal unsafe void CheckMemorySection()

external/corefx/src/System.Text.Encoding.CodePages/src/System/Text/DBCSCodePageEncoding.cs

@@ -8,6 +8,7 @@ using System.Diagnostics;
 using System.Text;
 using System.Threading;
 using System.Security;
+using System.Runtime.CompilerServices;
 
 namespace System.Text
 {
@@ -106,7 +107,9 @@ namespace System.Text
 
                 // Get our mapped section (bytes to allocate = 2 bytes per 65536 Unicode chars + 2 bytes per 65536 DBCS chars)
                 // Plus 4 byte to remember CP # when done loading it. (Don't want to get IA64 or anything out of alignment)
-                byte* pNativeMemory = GetNativeMemory(65536 * 2 * 2 + 4 + iExtraBytes);
+                int sizeToAllocate = 65536 * 2 * 2 + 4 + iExtraBytes;
+                byte* pNativeMemory = GetNativeMemory(sizeToAllocate);
+                Unsafe.InitBlockUnaligned(pNativeMemory, 0, (uint)sizeToAllocate);
 
                 mapBytesToUnicode = (char*)pNativeMemory;
                 mapUnicodeToBytes = (ushort*)(pNativeMemory + 65536 * 2);

external/corefx/src/System.Text.Encoding.CodePages/src/System/Text/SBCSCodePageEncoding.cs

@@ -9,6 +9,7 @@ using System.Text;
 using System.Threading;
 using System.Globalization;
 using System.Security;
+using System.Runtime.CompilerServices;
 
 namespace System.Text
 {
@@ -33,28 +34,6 @@ namespace System.Text
         {
         }
 
-        // Method assumes that memory pointer is aligned
-        private static unsafe void ZeroMemAligned(byte* buffer, int count)
-        {
-            long* pLong = (long*)buffer;
-            long* pLongEnd = (long*)(buffer + count - sizeof(long));
-
-            while (pLong < pLongEnd)
-            {
-                *pLong = 0;
-                pLong++;
-            }
-
-            byte* pByte = (byte*)pLong;
-            byte* pEnd = buffer + count;
-
-            while (pByte < pEnd)
-            {
-                *pByte = 0;
-                pByte++;
-            }
-        }
-
         // We have a managed code page entry, so load our tables
         // SBCS data section looks like:
         //
@@ -93,7 +72,7 @@ namespace System.Text
                 const int CodePageNumberSize = 4;
                 int bytesToAllocate = UnicodeToBytesMappingSize + BytesToUnicodeMappingSize + CodePageNumberSize + iExtraBytes;
                 byte* pNativeMemory = GetNativeMemory(bytesToAllocate);
-                ZeroMemAligned(pNativeMemory, bytesToAllocate);
+                Unsafe.InitBlockUnaligned(pNativeMemory, 0, (uint)bytesToAllocate);
 
                 char* mapBytesToUnicode = (char*)pNativeMemory;
                 byte* mapUnicodeToBytes = (byte*)(pNativeMemory + 256 * 2);
@@ -131,7 +110,7 @@ namespace System.Text
                         }
                     }
                 }
-                
+
                 _mapBytesToUnicode = mapBytesToUnicode;
                 _mapUnicodeToBytes = mapUnicodeToBytes;
             }