HGlobalMemory.cs

// based on https://github.com/dotnet/corefx/blob/389d7ee/src/System.Memory/tests/Memory/CustomMemoryForTest.cs
unsafe class HGlobalMemory : OwnedMemory<byte>
{
	private bool _disposed;
	private int _referenceCount;
	private byte* _buffer;
	private int _length;

	public HGlobalMemory(int length)
	{
		_buffer = (byte*)Marshal.AllocHGlobal(length);
		_length = length;
	}

	public override int Length => _length;

	public override bool IsDisposed => _disposed;

	protected override bool IsRetained => _referenceCount > 0;

	public override Span<byte> AsSpan()
	{
		if (IsDisposed)
			throw new ObjectDisposedException(nameof(HGlobalMemory));
		return new Span<byte>(_buffer, _length);
	}

	public override MemoryHandle Pin()
	{
		Retain();
		return new MemoryHandle(this, _buffer);
	}

	protected override bool TryGetArray(out ArraySegment<byte> arraySegment)
	{
		if (IsDisposed)
			throw new ObjectDisposedException(nameof(HGlobalMemory));
		arraySegment = default;
		return false;
	}

	protected override void Dispose(bool disposing)
	{
		if (_disposed)
			return;

		Marshal.FreeHGlobal((IntPtr)_buffer);
		_buffer = null;

		if (disposing)
			GC.SuppressFinalize(this);

		_disposed = true;
	}

	~HGlobalMemory() => Dispose(false);

	public override void Retain()
	{
		if (IsDisposed)
			throw new ObjectDisposedException(nameof(HGlobalMemory));
		Interlocked.Increment(ref _referenceCount);
	}

	public override bool Release()
	{
		int newRefCount = Interlocked.Decrement(ref _referenceCount);

		if (newRefCount < 0)
			throw new InvalidOperationException();

		return newRefCount != 0;
	}
}