Merge "Frameworks/base: Add removeAll for ArraySet"

core/java/android/util/ArraySet.java

@@ -467,6 +467,26 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
         return (E)old;
     }
 
+    /**
+     * Perform a {@link #remove(Object)} of all values in <var>array</var>
+     * @param array The array whose contents are to be removed.
+     */
+    public boolean removeAll(ArraySet<? extends E> array) {
+        // TODO: If array is sufficiently large, a marking approach might be beneficial. In a first
+        //       pass, use the property that the sets are sorted by hash to make this linear passes
+        //       (except for hash collisions, which means worst case still n*m), then do one
+        //       collection pass into a new array. This avoids binary searches and excessive memcpy.
+        final int N = array.mSize;
+
+        // Note: ArraySet does not make thread-safety guarantees. So instead of OR-ing together all
+        //       the single results, compare size before and after.
+        final int originalSize = mSize;
+        for (int i = 0; i < N; i++) {
+            remove(array.valueAt(i));
+        }
+        return originalSize != mSize;
+    }
+
     /**
      * Return the number of items in this array map.
      */