From 2a244bbbe0163d23562b0984b104a3b4031dbee0 Mon Sep 17 00:00:00 2001
From: John <johndygit@live.com.ph>
Date: Fri, 11 Mar 2016 06:54:15 +0800
Subject: [PATCH] Explicit AnimationStateData key in C#.

From user issue: http://esotericsoftware.com/forum/Performance-issue-of-KeyValuePair-5966
---
 spine-csharp/src/AnimationStateData.cs | 31 +++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/spine-csharp/src/AnimationStateData.cs b/spine-csharp/src/AnimationStateData.cs
index eea87429e..bf36b2c55 100644
--- a/spine-csharp/src/AnimationStateData.cs
+++ b/spine-csharp/src/AnimationStateData.cs
@@ -35,7 +35,7 @@ using System.Collections.Generic;
 namespace Spine {
 	public class AnimationStateData {
 		internal SkeletonData skeletonData;
-		private Dictionary<KeyValuePair<Animation, Animation>, float> animationToMixTime = new Dictionary<KeyValuePair<Animation, Animation>, float>();
+		private Dictionary<AnimationPair, float> animationToMixTime = new Dictionary<AnimationPair, float>(AnimationPairComparer.Instance);
 		internal float defaultMix;
 
 		public SkeletonData SkeletonData { get { return skeletonData; } }
@@ -56,16 +56,41 @@ namespace Spine {
 		public void SetMix (Animation from, Animation to, float duration) {
 			if (from == null) throw new ArgumentNullException("from cannot be null.");
 			if (to == null) throw new ArgumentNullException("to cannot be null.");
-			KeyValuePair<Animation, Animation> key = new KeyValuePair<Animation, Animation>(from, to);
+			AnimationPair key = new AnimationPair(from, to);
 			animationToMixTime.Remove(key);
 			animationToMixTime.Add(key, duration);
 		}
 
 		public float GetMix (Animation from, Animation to) {
-			KeyValuePair<Animation, Animation> key = new KeyValuePair<Animation, Animation>(from, to);
+			AnimationPair key = new AnimationPair(from, to);
 			float duration;
 			if (animationToMixTime.TryGetValue(key, out duration)) return duration;
 			return defaultMix;
 		}
+
+		struct AnimationPair {
+			public readonly Animation a1;
+			public readonly Animation a2;
+
+			public AnimationPair (Animation a1, Animation a2) {
+				this.a1 = a1;
+				this.a2 = a2;
+			}
+		}
+
+		// Avoids boxing in the dictionary.
+		class AnimationPairComparer : IEqualityComparer<AnimationPair> {
+			internal static readonly AnimationPairComparer Instance = new AnimationPairComparer();
+
+			bool IEqualityComparer<AnimationPair>.Equals (AnimationPair x, AnimationPair y) {
+				return ReferenceEquals(x.a1, y.a1) && ReferenceEquals(x.a2, y.a2);
+			}
+
+			int IEqualityComparer<AnimationPair>.GetHashCode (AnimationPair obj) {
+				// from Tuple.CombineHashCodes // return (((h1 << 5) + h1) ^ h2);
+				int h1 = obj.a1.GetHashCode();
+				return (((h1 << 5) + h1) ^ obj.a2.GetHashCode());
+			}
+		}
 	}
 }