[Truffle] Simpler capacity computation not requiring a loop.

* Does not always ensure power-of-two capacity. * But also avoids huge growth when unneeded.
jruby · Nov 24, 2015 · 19457f5 · 19457f5
1 parent 9f7fefc
commit 19457f5
Showing 1 changed file with 5 additions and 10 deletions.
diff --git a/truffle/src/main/java/org/jruby/truffle/runtime/array/ArrayUtils.java b/truffle/src/main/java/org/jruby/truffle/runtime/array/ArrayUtils.java
@@ -364,17 +364,12 @@ public static int capacity(int current, int needed) {
         if (needed < INITIAL_CAPACITY) {
             return INITIAL_CAPACITY;
         } else {
-            int capacity = current;
-
-            if (capacity == 0) {
-                capacity = INITIAL_CAPACITY;
-            }
-
-            while (capacity < needed) {
-                capacity *= 2;
+            final int newCapacity = current << 1;
+            if (newCapacity >= needed) {
+                return newCapacity;
+            } else {
+                return needed;
             }
-
-            return capacity;
         }
     }