From 59ea5c58252df8448eb75d83490a51f0cbfcf598 Mon Sep 17 00:00:00 2001
From: ahsonkhan <ahson_ahmedk@yahoo.com>
Date: Wed, 6 Dec 2017 19:49:51 -0800
Subject: [PATCH] Add optional integer offset to OwnedMemory Pin

---
 src/mscorlib/shared/System/Buffers/MemoryHandle.cs | 12 ------------
 src/mscorlib/shared/System/Buffers/OwnedMemory.cs  |  2 +-
 src/mscorlib/shared/System/Memory.cs               |  3 +--
 src/mscorlib/shared/System/ReadOnlyMemory.cs       |  3 +--
 4 files changed, 3 insertions(+), 17 deletions(-)

diff --git a/src/mscorlib/shared/System/Buffers/MemoryHandle.cs b/src/mscorlib/shared/System/Buffers/MemoryHandle.cs
index 60592144a591..8a6b8461aca0 100644
--- a/src/mscorlib/shared/System/Buffers/MemoryHandle.cs
+++ b/src/mscorlib/shared/System/Buffers/MemoryHandle.cs
@@ -21,18 +21,6 @@ public unsafe struct MemoryHandle : IDisposable
             _handle = handle;
         }
 
-        internal void AddOffset(int offset)
-        {
-            if (_pointer == null)
-            {
-                ThrowHelper.ThrowArgumentNullException(ExceptionArgument.pointer);
-            }
-            else
-            {
-                _pointer = (void*)((byte*)_pointer + offset);
-            }
-        }
-
         [CLSCompliant(false)]
         public void* Pointer => _pointer;
 
diff --git a/src/mscorlib/shared/System/Buffers/OwnedMemory.cs b/src/mscorlib/shared/System/Buffers/OwnedMemory.cs
index 116767073dd7..5ed7d95aa92c 100644
--- a/src/mscorlib/shared/System/Buffers/OwnedMemory.cs
+++ b/src/mscorlib/shared/System/Buffers/OwnedMemory.cs
@@ -25,7 +25,7 @@ public Memory<T> Memory
             }
         }
 
-        public abstract MemoryHandle Pin();
+        public abstract MemoryHandle Pin(int offset = 0);
 
         protected internal abstract bool TryGetArray(out ArraySegment<T> arraySegment);
 
diff --git a/src/mscorlib/shared/System/Memory.cs b/src/mscorlib/shared/System/Memory.cs
index e66a61e21024..2e85da7e9ca7 100644
--- a/src/mscorlib/shared/System/Memory.cs
+++ b/src/mscorlib/shared/System/Memory.cs
@@ -233,8 +233,7 @@ public unsafe MemoryHandle Retain(bool pin = false)
             {
                 if (_index < 0)
                 {
-                    memoryHandle = ((OwnedMemory<T>)_object).Pin();
-                    memoryHandle.AddOffset((_index & RemoveOwnedFlagBitMask) * Unsafe.SizeOf<T>());
+                    memoryHandle = ((OwnedMemory<T>)_object).Pin((_index & RemoveOwnedFlagBitMask) * Unsafe.SizeOf<T>());
                 }
                 else if (typeof(T) == typeof(char) && _object is string s)
                 {
diff --git a/src/mscorlib/shared/System/ReadOnlyMemory.cs b/src/mscorlib/shared/System/ReadOnlyMemory.cs
index d68f622cce7a..18ad7a9673cb 100644
--- a/src/mscorlib/shared/System/ReadOnlyMemory.cs
+++ b/src/mscorlib/shared/System/ReadOnlyMemory.cs
@@ -215,8 +215,7 @@ public unsafe MemoryHandle Retain(bool pin = false)
             {
                 if (_index < 0)
                 {
-                    memoryHandle = ((OwnedMemory<T>)_object).Pin();
-                    memoryHandle.AddOffset((_index & RemoveOwnedFlagBitMask) * Unsafe.SizeOf<T>());
+                    memoryHandle = ((OwnedMemory<T>)_object).Pin((_index & RemoveOwnedFlagBitMask) * Unsafe.SizeOf<T>());
                 }
                 else if (typeof(T) == typeof(char) && _object is string s)
                 {