From 6f50e7818889ef2ac77c9e55dc88ba5e8b50fd15 Mon Sep 17 00:00:00 2001
From: cosmonaut <evan@moonside.games>
Date: Thu, 2 Nov 2023 12:15:21 -0700
Subject: [PATCH] add relation count methods

---
 .../Compatibility/EntityComponentReader.cs    |  4 ++++
 src/Rev2/World.cs                             | 24 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/src/Rev2/Compatibility/EntityComponentReader.cs b/src/Rev2/Compatibility/EntityComponentReader.cs
index 14c944c..e7bacd9 100644
--- a/src/Rev2/Compatibility/EntityComponentReader.cs
+++ b/src/Rev2/Compatibility/EntityComponentReader.cs
@@ -25,8 +25,12 @@ public abstract class EntityComponentReader
 	protected ReverseSpanEnumerator<EntityId> OutRelations<T>(in EntityId entity) where T : unmanaged => World.OutRelations<T>(entity);
 	protected EntityId OutRelationSingleton<T>(in EntityId entity) where T : unmanaged => World.OutRelationSingleton<T>(entity);
 	protected bool HasOutRelation<T>(in EntityId entity) where T : unmanaged => World.HasOutRelation<T>(entity);
+	protected int OutRelationCount<T>(in EntityId entity) where T : unmanaged => World.OutRelationCount<T>(entity);
+	protected EntityId NthOutRelation<T>(in EntityId entity, int n) where T : unmanaged => World.NthOutRelation<T>(entity, n);
 
 	protected ReverseSpanEnumerator<EntityId> InRelations<T>(in EntityId entity) where T : unmanaged => World.InRelations<T>(entity);
 	protected EntityId InRelationSingleton<T>(in EntityId entity) where T : unmanaged => World.InRelationSingleton<T>(entity);
 	protected bool HasInRelation<T>(in EntityId entity) where T : unmanaged => World.HasInRelation<T>(entity);
+	protected int InRelationCount<T>(in EntityId entity) where T : unmanaged => World.InRelationCount<T>(entity);
+	protected EntityId NthInRelation<T>(in EntityId entity, int n) where T : unmanaged => World.NthInRelation<T>(entity, n);
 }
diff --git a/src/Rev2/World.cs b/src/Rev2/World.cs
index 6dbe7e0..e3fbdb1 100644
--- a/src/Rev2/World.cs
+++ b/src/Rev2/World.cs
@@ -407,6 +407,18 @@ public class World : IDisposable
 		return relationStorage.HasOutRelation(entity);
 	}
 
+	public int OutRelationCount<T>(in EntityId entity) where T : unmanaged
+	{
+		var relationStorage = GetRelationStorage<T>();
+		return relationStorage.OutRelationCount(entity);
+	}
+
+	public EntityId NthOutRelation<T>(in EntityId entity, int n) where T : unmanaged
+	{
+		var relationStorage = GetRelationStorage<T>();
+		return relationStorage.OutNth(entity, n);
+	}
+
 	public ReverseSpanEnumerator<EntityId> InRelations<T>(EntityId entity) where T : unmanaged
 	{
 		var relationStorage = GetRelationStorage<T>();
@@ -425,6 +437,18 @@ public class World : IDisposable
 		return relationStorage.HasInRelation(entity);
 	}
 
+	public int InRelationCount<T>(in EntityId entity) where T : unmanaged
+	{
+		var relationStorage = GetRelationStorage<T>();
+		return relationStorage.InRelationCount(entity);
+	}
+
+	public EntityId NthInRelation<T>(in EntityId entity, int n) where T : unmanaged
+	{
+		var relationStorage = GetRelationStorage<T>();
+		return relationStorage.InNth(entity, n);
+	}
+
 	// used as a fast path by Archetype.ClearAll and snapshot restore
 	internal void FreeEntity(EntityId entityId)
 	{