Avoid doing unnecessary range checks when we're looping from start to end.

Make EntityLiving call AI logic every tick again.
Rework PathfinderGoalSelector logic.

Adds UnsafeList for use in places where we use ArrayList and know we won't
get index out of range errors. Added usage to World's tickEntities, Chunk's
entitySlices to speed up searching for entities, and to PathfinderGoalSelector
to speed up dealing with AI goals.

Reworked logic in PathfinderGoalSelector with help from fullwall. This code
no longer uses an extra ArrayList for setting up goals and only updates which
goals should be run every other time it is called.

Removed only calling PathfinderGoalSelector every other tick from EntityLiving
as we now only setup new goals every other tick. This ensures existing goals
run every tick to properly update mob movement.

src/main/java/net/minecraft/server/PathfinderGoalSelector.java

@@ -2,12 +2,15 @@ package net.minecraft.server;
 
 import java.util.ArrayList;
 import java.util.Iterator;
+import org.bukkit.craftbukkit.util.UnsafeList; // CraftBukkit
 
 public class PathfinderGoalSelector {
 
-    private ArrayList a = new ArrayList();
-    private ArrayList b = new ArrayList();
-    private ArrayList arraylist = new ArrayList(); // CraftBukkit - create list for object reuse
+    // CraftBukkit start - use UnsafeList, add boolean for picking goals
+    private UnsafeList a = new UnsafeList(16);
+    private UnsafeList b = new UnsafeList(16);
+    boolean oddCall = true;
+    // CraftBukkit end
 
     public PathfinderGoalSelector() {}
 
@@ -16,12 +19,12 @@ public class PathfinderGoalSelector {
     }
 
     public void a() {
-        //ArrayList arraylist = new ArrayList(); // CraftBukkit
-        arraylist.clear(); // CraftBukkit - prepare reused list
+        //ArrayList arraylist = new ArrayList(); // CraftBukkit - removed usage
 
-        // CraftBukkit start - don't use iterators for private fields
+        // CraftBukkit start - don't use iterators for private fields, only run every other call
+        if (oddCall) {
         for (int i = 0; i < this.a.size(); i++) {
-            PathfinderGoalSelectorItem pathfindergoalselectoritem = (PathfinderGoalSelectorItem) this.a.get(i);
+            PathfinderGoalSelectorItem pathfindergoalselectoritem = (PathfinderGoalSelectorItem) this.a.unsafeGet(i); // CraftBukkit - use unsafeGet
             boolean flag = this.b.contains(pathfindergoalselectoritem);
 
             if (flag) {
@@ -34,36 +37,44 @@ public class PathfinderGoalSelector {
             }
 
             if (this.a(pathfindergoalselectoritem) && pathfindergoalselectoritem.a.a()) {
-                arraylist.add(pathfindergoalselectoritem);
+                // CraftBukkit start - call method now
+                // arraylist.add(pathfindergoalselectoritem);
+                pathfindergoalselectoritem.a.c();
+                // CraftBukkit end
                 this.b.add(pathfindergoalselectoritem);
             }
         }
+        }
+        oddCall = !oddCall;
         // CraftBukkit end
 
         boolean flag1 = false;
 
-        if (flag1 && arraylist.size() > 0) {
+        // CraftBukkit start - removed usage of arraylist
+        /*if (flag1 && arraylist.size() > 0) {
             System.out.println("Starting: ");
-        }
+        }*/
+        // CraftBukkit end
 
         Iterator iterator1;
         PathfinderGoalSelectorItem pathfindergoalselectoritem1;
 
-        //CraftBukkit start - don't use iterators for private fields
-        for (int i = 0; i < arraylist.size(); i++) {
-            pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) arraylist.get(i);
-            pathfindergoalselectoritem1.a.c();
+        // CraftBukkit start - removed usage of arraylist
+        /*for (iterator1 = arraylist.iterator(); iterator1.hasNext(); pathfindergoalselectoritem1.a.c()) {
+            pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) iterator1.next();
             if (flag1) {
                 System.out.println(pathfindergoalselectoritem1.a.toString() + ", ");
             }
-        }
+        }*/
+        // CraftBukkit end
 
         if (flag1 && this.b.size() > 0) {
             System.out.println("Running: ");
         }
 
+        // CraftBukkit start - don't use iterators for private fields
         for (int i = 0; i < this.b.size(); i++) {
-            pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) this.b.get(i);
+            pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) this.b.unsafeGet(i); // CraftBukkit - use unsafeGet
             pathfindergoalselectoritem1.a.e();
             if (flag1) {
                 System.out.println(pathfindergoalselectoritem1.a.toString());
@@ -75,14 +86,14 @@ public class PathfinderGoalSelector {
     private boolean a(PathfinderGoalSelectorItem pathfindergoalselectoritem) {
         // CraftBukkit start - don't use iterators for private fields
         for (int i = 0; i < this.a.size(); i++) {
-            PathfinderGoalSelectorItem pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) this.a.get(i);
+            PathfinderGoalSelectorItem pathfindergoalselectoritem1 = (PathfinderGoalSelectorItem) this.a.unsafeGet(i); // CraftBukkit - use unsafeGet
 
             if (pathfindergoalselectoritem1 != pathfindergoalselectoritem) {
                 if (pathfindergoalselectoritem.b >= pathfindergoalselectoritem1.b) {
-                    if (this.b.contains(pathfindergoalselectoritem1) && !this.a(pathfindergoalselectoritem, pathfindergoalselectoritem1)) {
+                    if (!this.a(pathfindergoalselectoritem, pathfindergoalselectoritem1) && this.b.contains(pathfindergoalselectoritem1)) { // CraftBukkit - switch order
                         return false;
                     }
-                } else if (this.b.contains(pathfindergoalselectoritem1) && !pathfindergoalselectoritem1.a.g()) {
+                } else if (!pathfindergoalselectoritem1.a.g() && this.b.contains(pathfindergoalselectoritem1)) { // CraftBukkit - switch order
                     return false;
                 }
             }