perf tweaks to count, nth

2 files changed, 13 insertions, 1 deletions

diff --git a/src/jvm/clojure/lang/ArrayChunk.java b/src/jvm/clojure/lang/ArrayChunk.java
index 92240440..3d3d645a 100644
--- a/src/jvm/clojure/lang/ArrayChunk.java
+++ b/src/jvm/clojure/lang/ArrayChunk.java
@@ -12,7 +12,7 @@
 
 package clojure.lang;
 
-public class ArrayChunk implements Indexed{
+public final class ArrayChunk implements Indexed{
 
 final Object[] array;
 final int off;
diff --git a/src/jvm/clojure/lang/RT.java b/src/jvm/clojure/lang/RT.java
index 2053273d..0a33f55a 100644
--- a/src/jvm/clojure/lang/RT.java
+++ b/src/jvm/clojure/lang/RT.java
@@ -493,6 +493,12 @@ static public IPersistentMap meta(Object x){
 	return null;
 }
 
+public static int count(Counted o){
+	if(o != null)
+		return o.count();
+	return 0;
+}
+
 public static int count(Object o){
 	if(o instanceof Counted)
 		return ((Counted) o).count();
@@ -711,6 +717,12 @@ static public Object dissoc(Object coll, Object key) throws Exception{
 	return ((IPersistentMap) coll).without(key);
 }
 
+static public Object nth(Indexed coll, int n){
+	if(coll != null)
+		return coll.nth(n);
+	return null;
+}
+
 static public Object nth(Object coll, int n){
 	if(coll instanceof Indexed)
 		return ((Indexed) coll).nth(n);