Imported Upstream version 6.4.0.137

Former-commit-id: 943baa9f16a098c33e129777827f3a9d20da00d6

mcs/class/System.Private.CoreLib/System/ArgIterator.cs

@@ -0,0 +1,104 @@
+// 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.
+
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace System 
+{
+	[StructLayout (LayoutKind.Auto)]
+	public ref struct ArgIterator
+	{
+#pragma warning disable 169, 414
+		IntPtr sig;
+		IntPtr args;
+		int next_arg;
+		int num_args;
+#pragma warning restore 169, 414
+
+		[MethodImpl (MethodImplOptions.InternalCall)]
+		extern void Setup (IntPtr argsp, IntPtr start);
+
+		public ArgIterator (RuntimeArgumentHandle arglist)
+		{
+			sig = IntPtr.Zero;
+			args = IntPtr.Zero;
+			next_arg = num_args = 0;
+			if (arglist.args == IntPtr.Zero)
+				throw new PlatformNotSupportedException ();
+			Setup (arglist.args, IntPtr.Zero);
+		}
+
+		[CLSCompliant (false)]
+		unsafe public ArgIterator (RuntimeArgumentHandle arglist, void *ptr)
+		{
+			sig = IntPtr.Zero;
+			args = IntPtr.Zero;
+			next_arg = num_args = 0;
+			if (arglist.args == IntPtr.Zero)
+				throw new PlatformNotSupportedException ();
+			Setup (arglist.args, (IntPtr) ptr);
+		}
+
+		public void End ()
+		{
+			next_arg = num_args;
+		}
+
+		public override bool Equals (object? o)
+		{
+			throw new NotSupportedException ("ArgIterator does not support Equals.");
+		}
+
+		public override int GetHashCode ()
+		{
+			return sig.GetHashCode ();
+		}
+
+		[CLSCompliant (false)]
+		public TypedReference GetNextArg ()
+		{
+			if (num_args == next_arg)
+				throw new InvalidOperationException ("Invalid iterator position.");
+			TypedReference result = new TypedReference ();
+			unsafe {
+				IntGetNextArg (&result);
+			}
+			return result;
+		}
+
+		[MethodImpl (MethodImplOptions.InternalCall)]
+		extern unsafe void IntGetNextArg (void *res);
+
+		[CLSCompliant (false)]
+		public TypedReference GetNextArg (RuntimeTypeHandle rth)
+		{
+			if (num_args == next_arg)
+				throw new InvalidOperationException ("Invalid iterator position.");
+			TypedReference result = new TypedReference ();
+			unsafe {
+				IntGetNextArgWithType (&result, rth.Value);
+			}
+			return result;
+		}
+
+		[MethodImpl (MethodImplOptions.InternalCall)]
+		extern unsafe void IntGetNextArgWithType (void *res, IntPtr rth);
+
+		public RuntimeTypeHandle GetNextArgType ()
+		{
+			if (num_args == next_arg)
+				throw new InvalidOperationException ("Invalid iterator position.");
+			return new RuntimeTypeHandle (IntGetNextArgType ());
+		}
+
+		[MethodImpl (MethodImplOptions.InternalCall)]
+		extern IntPtr IntGetNextArgType ();
+
+		public int GetRemainingCount ()
+		{
+			return num_args - next_arg;
+		}
+	}
+}