Add Span<T>

This includes all the core types:

* Span<T>
* ReadOnlySpan<T>
* Memory<T>
* ReadOnlyMemory<T>
* MemoryExtensions
* MemoryMarshal

It doesn't, however, include spanified version of our APIs or the buffer work
yet.

netstandard/ref/System.Buffers.cs

@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Buffers
+{
+    public partial interface IPinnable
+    {
+        System.Buffers.MemoryHandle Pin(int elementIndex);
+        void Unpin();
+    }
+    public partial struct MemoryHandle : System.IDisposable
+    {
+        [System.CLSCompliantAttribute(false)]
+        public unsafe MemoryHandle(void* pointer, System.Runtime.InteropServices.GCHandle handle = default(System.Runtime.InteropServices.GCHandle), System.Buffers.IPinnable pinnable = null) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public unsafe void* Pointer { get { throw null; } }
+        public void Dispose() { }
+    }
+}

netstandard/ref/System.Runtime.InteropServices.cs

@@ -714,6 +714,26 @@ public partial class MarshalDirectiveException : System.SystemException
         public MarshalDirectiveException(string message) { }
         public MarshalDirectiveException(string message, System.Exception inner) { }
     }
+    public static partial class MemoryMarshal
+    {
+        public static System.ReadOnlySpan<byte> AsBytes<T>(System.ReadOnlySpan<T> span) where T : struct { throw null; }
+        public static System.Span<byte> AsBytes<T>(System.Span<T> span) where T : struct { throw null; }
+        public static System.Memory<T> AsMemory<T>(System.ReadOnlyMemory<T> memory) { throw null; }
+        public static System.ReadOnlySpan<TTo> Cast<TFrom, TTo>(System.ReadOnlySpan<TFrom> span) where TFrom : struct where TTo : struct { throw null; }
+        public static System.Span<TTo> Cast<TFrom, TTo>(System.Span<TFrom> span) where TFrom : struct where TTo : struct { throw null; }
+        public static System.Memory<T> CreateFromPinnedArray<T>(T[] array, int start, int length) { throw null; }
+        public static System.ReadOnlySpan<T> CreateReadOnlySpan<T>(ref T reference, int length) { throw null; }
+        public static System.Span<T> CreateSpan<T>(ref T reference, int length) { throw null; }
+        public static ref T GetReference<T>(System.ReadOnlySpan<T> span) { throw null; }
+        public static ref T GetReference<T>(System.Span<T> span) { throw null; }
+        public static T Read<T>(System.ReadOnlySpan<byte> source) where T : struct { throw null; }
+        public static System.Collections.Generic.IEnumerable<T> ToEnumerable<T>(System.ReadOnlyMemory<T> memory) { throw null; }
+        public static bool TryGetArray<T>(System.ReadOnlyMemory<T> memory, out System.ArraySegment<T> segment) { segment = default(System.ArraySegment<T>); throw null; }
+        public static bool TryGetString(System.ReadOnlyMemory<char> memory, out string text, out int start, out int length) { text = default(string); start = default(int); length = default(int); throw null; }
+        public static bool TryRead<T>(System.ReadOnlySpan<byte> source, out T value) where T : struct { value = default(T); throw null; }
+        public static bool TryWrite<T>(System.Span<byte> destination, ref T value) where T : struct { throw null; }
+        public static void Write<T>(System.Span<byte> destination, ref T value) where T : struct { }
+    }
     [System.AttributeUsageAttribute((System.AttributeTargets)(2048), Inherited=false)]
     public sealed partial class OptionalAttribute : System.Attribute
     {

netstandard/ref/netstandard.csproj

@@ -24,6 +24,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Microsoft.Win32.SafeHandles.cs" />
+    <Compile Include="System.Buffers.cs" />
     <Compile Include="System.CodeDom.Compiler.cs" />
     <Compile Include="System.Collections.Concurrent.cs" />
     <Compile Include="System.Collections.cs" />

netstandard/src/ApiCompatBaseline.net461.txt

@@ -4,7 +4,12 @@ MembersMustExist : Member 'System.AppContext.TargetFrameworkName.get()' does not
 TypeCannotChangeClassification : Type 'System.ArraySegment<T>' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.ConsoleKeyInfo' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.DateTime' is marked as readonly in the contract so it must also be marked readonly in the implementation.
+TypesMustExist : Type 'System.Memory<T>' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.MemoryExtensions' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.ReadOnlyMemory<T>' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.ReadOnlySpan<T>' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.RuntimeArgumentHandle' is a 'struct' in the implementation but is a 'ref struct' in the contract.
+TypesMustExist : Type 'System.Span<T>' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'System.StringNormalizationExtensions' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.TimeZoneInfo.TransitionTime' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 CannotRemoveBaseTypeOrInterface : Type 'System.Tuple<T1>' does not implement interface 'System.Runtime.CompilerServices.ITuple' in the implementation but it does in the contract.
@@ -38,6 +43,8 @@ CannotRemoveBaseTypeOrInterface : Type 'System.ValueTuple<T1, T2, T3, T4, T5>' d
 CannotRemoveBaseTypeOrInterface : Type 'System.ValueTuple<T1, T2, T3, T4, T5, T6>' does not implement interface 'System.Runtime.CompilerServices.ITuple' in the implementation but it does in the contract.
 CannotRemoveBaseTypeOrInterface : Type 'System.ValueTuple<T1, T2, T3, T4, T5, T6, T7>' does not implement interface 'System.Runtime.CompilerServices.ITuple' in the implementation but it does in the contract.
 CannotRemoveBaseTypeOrInterface : Type 'System.ValueTuple<T1, T2, T3, T4, T5, T6, T7, TRest>' does not implement interface 'System.Runtime.CompilerServices.ITuple' in the implementation but it does in the contract.
+TypesMustExist : Type 'System.Buffers.IPinnable' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.Buffers.MemoryHandle' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.BitArray.LeftShift(System.Int32)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.BitArray.RightShift(System.Int32)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.DictionaryEntry.Deconstruct(System.Object, System.Object)' does not exist in the implementation but it does exist in the contract.
@@ -201,6 +208,7 @@ MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.PtrToStringUTF
 MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.PtrToStringUTF8(System.IntPtr, System.Int32)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.StringToCoTaskMemUTF8(System.String)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.ZeroFreeCoTaskMemUTF8(System.IntPtr)' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.Runtime.InteropServices.MemoryMarshal' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.Runtime.InteropServices.OSPlatform' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 MembersMustExist : Member 'System.Runtime.InteropServices.UnmanagedType System.Runtime.InteropServices.UnmanagedType.LPUTF8Str' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'System.Runtime.Serialization.DataContractSerializerExtensions' does not exist in the implementation but it does exist in the contract.
@@ -278,4 +286,4 @@ MembersMustExist : Member 'System.Xml.Linq.XNode.WriteToAsync(System.Xml.XmlWrit
 MembersMustExist : Member 'System.Xml.Linq.XProcessingInstruction.WriteToAsync(System.Xml.XmlWriter, System.Threading.CancellationToken)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Xml.Linq.XText.WriteToAsync(System.Xml.XmlWriter, System.Threading.CancellationToken)' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'System.Xml.XPath.XDocumentExtensions' does not exist in the implementation but it does exist in the contract.
-Total Issues: 279
+Total Issues: 287

netstandard/src/ApiCompatBaseline.xamarin.android.txt

@@ -2,7 +2,12 @@ Compat issues with assembly netstandard:
 TypeCannotChangeClassification : Type 'System.ArraySegment<T>' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.ConsoleKeyInfo' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.DateTime' is marked as readonly in the contract so it must also be marked readonly in the implementation.
+TypesMustExist : Type 'System.Memory<T>' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.MemoryExtensions' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.ReadOnlyMemory<T>' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.ReadOnlySpan<T>' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.RuntimeArgumentHandle' is a 'struct' in the implementation but is a 'ref struct' in the contract.
+TypesMustExist : Type 'System.Span<T>' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.TimeZoneInfo.TransitionTime' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 MembersMustExist : Member 'System.Type.GetMethod(System.String, System.Int32, System.Reflection.BindingFlags, System.Reflection.Binder, System.Reflection.CallingConventions, System.Type[], System.Reflection.ParameterModifier[])' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Type.GetMethod(System.String, System.Int32, System.Reflection.BindingFlags, System.Reflection.Binder, System.Type[], System.Reflection.ParameterModifier[])' does not exist in the implementation but it does exist in the contract.
@@ -17,6 +22,8 @@ MembersMustExist : Member 'System.Type.IsTypeDefinition.get()' does not exist in
 MembersMustExist : Member 'System.Type.IsVariableBoundArray.get()' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Type.MakeGenericMethodParameter(System.Int32)' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.TypedReference' is a 'struct' in the implementation but is a 'ref struct' in the contract.
+TypesMustExist : Type 'System.Buffers.IPinnable' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'System.Buffers.MemoryHandle..ctor(System.Void*, System.Runtime.InteropServices.GCHandle, System.Buffers.IPinnable)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.BitArray.LeftShift(System.Int32)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.BitArray.RightShift(System.Int32)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.Generic.Dictionary<TKey, TValue>.TrimExcess()' does not exist in the implementation but it does exist in the contract.
@@ -98,6 +105,7 @@ TypesMustExist : Type 'System.Runtime.CompilerServices.ValueTaskAwaiter' does no
 TypeCannotChangeClassification : Type 'System.Runtime.CompilerServices.YieldAwaitable' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.Runtime.CompilerServices.YieldAwaitable.YieldAwaiter' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.StringToCoTaskMemUTF8(System.String)' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.Runtime.InteropServices.MemoryMarshal' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.Runtime.Serialization.StreamingContext' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.Security.Cryptography.HashAlgorithmName' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 MembersMustExist : Member 'System.Text.Encoding.GetByteCount(System.String, System.Int32, System.Int32)' does not exist in the implementation but it does exist in the contract.
@@ -154,4 +162,4 @@ MembersMustExist : Member 'System.Xml.Linq.XProcessingInstruction.WriteToAsync(S
 MembersMustExist : Member 'System.Xml.Linq.XText.WriteToAsync(System.Xml.XmlWriter, System.Threading.CancellationToken)' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'System.Xml.Serialization.SchemaImporter' does not exist in the implementation but it does exist in the contract.
 CannotRemoveBaseTypeOrInterface : Type 'System.Xml.Serialization.XmlSchemaImporter' does not inherit from base type 'System.Xml.Serialization.SchemaImporter' in the implementation but it does in the contract.
-Total Issues: 155
+Total Issues: 163

netstandard/src/ApiCompatBaseline.xamarin.ios.txt

@@ -2,7 +2,12 @@ Compat issues with assembly netstandard:
 TypeCannotChangeClassification : Type 'System.ArraySegment<T>' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.ConsoleKeyInfo' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.DateTime' is marked as readonly in the contract so it must also be marked readonly in the implementation.
+TypesMustExist : Type 'System.Memory<T>' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.MemoryExtensions' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.ReadOnlyMemory<T>' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.ReadOnlySpan<T>' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.RuntimeArgumentHandle' is a 'struct' in the implementation but is a 'ref struct' in the contract.
+TypesMustExist : Type 'System.Span<T>' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.TimeZoneInfo.TransitionTime' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 MembersMustExist : Member 'System.Type.GetMethod(System.String, System.Int32, System.Reflection.BindingFlags, System.Reflection.Binder, System.Reflection.CallingConventions, System.Type[], System.Reflection.ParameterModifier[])' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Type.GetMethod(System.String, System.Int32, System.Reflection.BindingFlags, System.Reflection.Binder, System.Type[], System.Reflection.ParameterModifier[])' does not exist in the implementation but it does exist in the contract.
@@ -17,6 +22,8 @@ MembersMustExist : Member 'System.Type.IsTypeDefinition.get()' does not exist in
 MembersMustExist : Member 'System.Type.IsVariableBoundArray.get()' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Type.MakeGenericMethodParameter(System.Int32)' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.TypedReference' is a 'struct' in the implementation but is a 'ref struct' in the contract.
+TypesMustExist : Type 'System.Buffers.IPinnable' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'System.Buffers.MemoryHandle..ctor(System.Void*, System.Runtime.InteropServices.GCHandle, System.Buffers.IPinnable)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.BitArray.LeftShift(System.Int32)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.BitArray.RightShift(System.Int32)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Collections.Generic.Dictionary<TKey, TValue>.TrimExcess()' does not exist in the implementation but it does exist in the contract.
@@ -105,6 +112,7 @@ MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.GetIDispatchFo
 MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.GetTypedObjectForIUnknown(System.IntPtr, System.Type)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.SetComObjectData(System.Object, System.Object, System.Object)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'System.Runtime.InteropServices.Marshal.StringToCoTaskMemUTF8(System.String)' does not exist in the implementation but it does exist in the contract.
+TypesMustExist : Type 'System.Runtime.InteropServices.MemoryMarshal' does not exist in the implementation but it does exist in the contract.
 TypeCannotChangeClassification : Type 'System.Runtime.Serialization.StreamingContext' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 TypeCannotChangeClassification : Type 'System.Security.Cryptography.HashAlgorithmName' is marked as readonly in the contract so it must also be marked readonly in the implementation.
 MembersMustExist : Member 'System.Text.Encoding.GetByteCount(System.String, System.Int32, System.Int32)' does not exist in the implementation but it does exist in the contract.
@@ -161,4 +169,4 @@ MembersMustExist : Member 'System.Xml.Linq.XProcessingInstruction.WriteToAsync(S
 MembersMustExist : Member 'System.Xml.Linq.XText.WriteToAsync(System.Xml.XmlWriter, System.Threading.CancellationToken)' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'System.Xml.Serialization.SchemaImporter' does not exist in the implementation but it does exist in the contract.
 CannotRemoveBaseTypeOrInterface : Type 'System.Xml.Serialization.XmlSchemaImporter' does not inherit from base type 'System.Xml.Serialization.SchemaImporter' in the implementation but it does in the contract.
-Total Issues: 162
+Total Issues: 170