Use inline-array

Author: viceroypenguin

AdventOfCode.Common/ValueArray.cs

@@ -1,48 +1,18 @@
-using System.Runtime.InteropServices;
+using System.Runtime.CompilerServices;
 
 namespace AdventOfCode.Common;
 
-[StructLayout(LayoutKind.Sequential)]
+#pragma warning disable IDE0044 // Add readonly modifier
+#pragma warning disable IDE0051 // Remove unused private members
+
+[InlineArray(4)]
 public record struct ValueArray4<T>
 {
-	public T _0, _1, _2, _3;
-
-	public readonly T this[int i] =>
-		i switch
-		{
-			0 => _0,
-			1 => _1,
-			2 => _2,
-			3 => _3,
-			_ => throw new ArgumentOutOfRangeException(nameof(i)),
-		};
+	private T _0;
 }
 
-[StructLayout(LayoutKind.Sequential)]
+[InlineArray(8)]
 public record struct ValueArray8<T>
 {
-	public T _0, _1, _2, _3, _4, _5, _6, _7;
-
-	public readonly T this[int i] =>
-		i switch
-		{
-			0 => _0,
-			1 => _1,
-			2 => _2,
-			3 => _3,
-			4 => _4,
-			5 => _5,
-			6 => _6,
-			7 => _7,
-			_ => throw new ArgumentOutOfRangeException(nameof(i)),
-		};
-}
-
-public static class ValueArrayExtensions
-{
-	public static Span<T> Span<T>(ref this ValueArray4<T> array) =>
-		MemoryMarshal.CreateSpan(ref array._0, 4);
-
-	public static Span<T> Span<T>(ref this ValueArray8<T> array) =>
-		MemoryMarshal.CreateSpan(ref array._0, 8);
+	private T _0;
 }

AdventOfCode.Puzzles/2021/day23.original.cs

@@ -12,15 +12,15 @@ public class Day_23_Original : IPuzzle
 		var start = new Board() { Padding = 0, };
 		for (var i = 0; i < 4; i++)
 		{
-			var room = start.Rooms.Span()[i].Span();
+			var room = start.Rooms[i];
 			room[0] = map[2][(i * 2) + 3];
 			room[1] = map[3][(i * 2) + 3];
 		}
 
 		var goal = new Board();
 		for (var i = 0; i < 4; i++)
 		{
-			var room = goal.Rooms.Span()[i].Span();
+			var room = goal.Rooms[i];
 			room[0] = (byte)('A' + i);
 			room[1] = (byte)('A' + i);
 		}
@@ -40,12 +40,12 @@ public class Day_23_Original : IPuzzle
 
 		for (var i = 0; i < 4; i++)
 		{
-			var room = start.Rooms.Span()[i].Span();
+			var room = start.Rooms[i];
 			room[3] = room[1];
 			room[1] = insert[i][0];
 			room[2] = insert[i][1];
 
-			room = goal.Rooms.Span()[i].Span();
+			room = goal.Rooms[i];
 			room[2] = (byte)('A' + i);
 			room[3] = (byte)('A' + i);
 		}
@@ -70,8 +70,8 @@ private static int GetCost(byte b) =>
 
 	private static (Board, int) MoveTokenToHallway(Board board, int cost, int room, int i, int hallway)
 	{
-		var roomSpan = board.Rooms.Span()[room].Span();
-		var hallwaySpan = board.Hallway.Span();
+		var roomSpan = board.Rooms[room];
+		var hallwaySpan = board.Hallway;
 
 		var moveCost = GetCost(roomSpan[i]);
 		var steps = GetSteps(room, hallway) + i + 1;
@@ -83,8 +83,8 @@ private static (Board, int) MoveTokenToHallway(Board board, int cost, int room,
 
 	private static (Board, int) MoveTokenToRoom(Board board, int cost, int room, int i, int hallway)
 	{
-		var roomSpan = board.Rooms.Span()[room].Span();
-		var hallwaySpan = board.Hallway.Span();
+		var roomSpan = board.Rooms[room];
+		var hallwaySpan = board.Hallway;
 
 		var moveCost = GetCost(hallwaySpan[hallway]);
 		var steps = GetSteps(room, hallway) + i + 1;
@@ -96,8 +96,8 @@ private static (Board, int) MoveTokenToRoom(Board board, int cost, int room, int
 
 	private static (Board, int) MoveTokenToRoom(Board board, int cost, int from, int i, int to, int j)
 	{
-		var fromSpan = board.Rooms.Span()[from].Span();
-		var toSpan = board.Rooms.Span()[to].Span();
+		var fromSpan = board.Rooms[from];
+		var toSpan = board.Rooms[to];
 
 		var moveCost = GetCost(fromSpan[i]);
 		var steps = (Math.Abs(from - to) * 2) + i + 1 + j + 1;