From c3251a51a9a43b79c2809354e4ab97d93728fb8a Mon Sep 17 00:00:00 2001
From: sakno <roman.sakno@gmail.com>
Date: Fri, 12 Jan 2024 08:07:09 +0200
Subject: [PATCH] Fixed regression

---
 src/DotNext.Tests/IO/StreamSourceTests.cs       |  2 +-
 src/DotNext.Unsafe/Buffers/UnmanagedMemory.cs   | 10 +++++++---
 .../Runtime/InteropServices/Pointer.cs          | 17 +++--------------
 3 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/src/DotNext.Tests/IO/StreamSourceTests.cs b/src/DotNext.Tests/IO/StreamSourceTests.cs
index 126aa56f4..488a12f72 100644
--- a/src/DotNext.Tests/IO/StreamSourceTests.cs
+++ b/src/DotNext.Tests/IO/StreamSourceTests.cs
@@ -289,7 +289,7 @@ public static void ReadApm()
         var buffer = new byte[4];
         src.Position = 1;
         var ar = src.BeginRead(buffer, 0, 2, null, "state");
-        False(ar.CompletedSynchronously);
+        True(ar.CompletedSynchronously);
         Equal("state", ar.AsyncState);
         True(ar.AsyncWaitHandle.WaitOne(DefaultTimeout));
         Equal(2, src.EndRead(ar));
diff --git a/src/DotNext.Unsafe/Buffers/UnmanagedMemory.cs b/src/DotNext.Unsafe/Buffers/UnmanagedMemory.cs
index bd6039759..6d5c5efc8 100644
--- a/src/DotNext.Unsafe/Buffers/UnmanagedMemory.cs
+++ b/src/DotNext.Unsafe/Buffers/UnmanagedMemory.cs
@@ -70,6 +70,10 @@ internal unsafe class UnmanagedMemory<T> : MemoryManager<T>
     private readonly bool owner;
     private void* address;
 
+    private UnmanagedMemory()
+    {
+    }
+
     internal UnmanagedMemory(nint address, int length)
     {
         Debug.Assert(address is not 0);
@@ -78,6 +82,8 @@ internal UnmanagedMemory(nint address, int length)
         Length = length;
     }
 
+    internal static UnmanagedMemory<T> CreateEmpty() => new();
+
     private protected UnmanagedMemory(int length, delegate*<nuint, nuint, void* > allocator)
     {
         Debug.Assert(length > 0);
@@ -105,7 +111,6 @@ public ref T this[int index]
     internal void Reallocate(int length)
     {
         ArgumentOutOfRangeException.ThrowIfNegativeOrZero(length);
-        ObjectDisposedException.ThrowIf(address is null, this);
 
         var size = (nuint)length * (nuint)sizeof(T);
         address = NativeMemory.Realloc(address, size);
@@ -117,8 +122,7 @@ public sealed override Span<T> GetSpan()
 
     public sealed override MemoryHandle Pin(int elementIndex = 0)
     {
-        ObjectDisposedException.ThrowIf(address is null, this);
-        ArgumentOutOfRangeException.ThrowIfNegative(elementIndex);
+        ArgumentOutOfRangeException.ThrowIfGreaterThanOrEqual((uint)elementIndex, (uint)Length, nameof(elementIndex));
 
         return new(Unsafe.Add<T>(address, elementIndex));
     }
diff --git a/src/DotNext.Unsafe/Runtime/InteropServices/Pointer.cs b/src/DotNext.Unsafe/Runtime/InteropServices/Pointer.cs
index 9d0eb33f4..b16cf9f1b 100644
--- a/src/DotNext.Unsafe/Runtime/InteropServices/Pointer.cs
+++ b/src/DotNext.Unsafe/Runtime/InteropServices/Pointer.cs
@@ -1047,20 +1047,9 @@ public unsafe int BitwiseCompare(Pointer<T> other, nuint count)
     /// <param name="length">The number of elements in the memory.</param>
     /// <returns>The instance of memory owner.</returns>
     public unsafe IMemoryOwner<T> ToMemoryOwner(int length)
-    {
-        nint address;
-        if (IsNull)
-        {
-            length = 0;
-            address = 0;
-        }
-        else
-        {
-            address = (nint)value;
-        }
-
-        return new Buffers.UnmanagedMemory<T>(address, length);
-    }
+        => IsNull
+            ? Buffers.UnmanagedMemory<T>.CreateEmpty()
+            : new Buffers.UnmanagedMemory<T>(Address, length);
 
     /// <summary>
     /// Obtains pointer to the memory represented by given memory handle.