Reusable buffers introduced.

PerfectNumbers.Core/PartialFactorPendingEntry.cs

@@ -0,0 +1,47 @@
+using System.Runtime.CompilerServices;
+
+namespace PerfectNumbers.Core;
+
+internal sealed class PartialFactorPendingEntry(ulong value, bool knownComposite)
+{
+	[ThreadStatic]
+	private static PartialFactorPendingEntry? _poolHead;
+	private PartialFactorPendingEntry? _next;
+
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	public static PartialFactorPendingEntry Rent(ulong value, bool knownComposite)
+	{
+		var poolHead = _poolHead;
+		if (poolHead == null)
+		{
+			return new(value, knownComposite);
+		}
+
+		_poolHead = poolHead._next;
+		poolHead.Value = value;
+		poolHead.KnownComposite = knownComposite;
+		poolHead.HasKnownPrimality = knownComposite;
+		poolHead.IsPrime = false;
+		return poolHead;
+	}
+
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	public static void Return(PartialFactorPendingEntry entry)
+	{
+		entry._next = _poolHead;
+		_poolHead = entry;
+	}
+
+	public ulong Value = value;
+	public bool KnownComposite = knownComposite;
+	public bool HasKnownPrimality = knownComposite;
+	public bool IsPrime = false;
+
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	public void WithPrimality(bool isPrime)
+	{
+		KnownComposite = KnownComposite || !isPrime;
+		HasKnownPrimality = true;
+		IsPrime = isPrime;
+	}
+}