1 files changed, 16 insertions, 29 deletions
diff --git a/core/java/android/util/SparseLongArray.java b/core/java/android/util/SparseLongArray.java
index 2f7a6fe63bb5..c608996c99bf 100644
--- a/core/java/android/util/SparseLongArray.java
+++ b/core/java/android/util/SparseLongArray.java
@@ -24,6 +24,7 @@ import com.android.internal.util.ArrayUtils;
  * than using a HashMap to map Integers to Longs.
  */
 public class SparseLongArray implements Cloneable {
+    static final long[] EMPTY_LONGS = new long[0];
 
     private int[] mKeys;
     private long[] mValues;
@@ -39,13 +40,19 @@ public class SparseLongArray implements Cloneable {
     /**
      * Creates a new SparseLongArray containing no mappings that will not
      * require any additional memory allocation to store the specified
-     * number of mappings.
+     * number of mappings.  If you supply an initial capacity of 0, the
+     * sparse array will be initialized with a light-weight representation
+     * not requiring any additional array allocations.
      */
     public SparseLongArray(int initialCapacity) {
-        initialCapacity = ArrayUtils.idealLongArraySize(initialCapacity);
-
-        mKeys = new int[initialCapacity];
-        mValues = new long[initialCapacity];
+        if (initialCapacity == 0) {
+            mKeys = SparseArray.EMPTY_INTS;
+            mValues = EMPTY_LONGS;
+        } else {
+            initialCapacity = ArrayUtils.idealLongArraySize(initialCapacity);
+            mKeys = new int[initialCapacity];
+            mValues = new long[initialCapacity];
+        }
         mSize = 0;
     }
 
@@ -75,7 +82,7 @@ public class SparseLongArray implements Cloneable {
      * if no such mapping has been made.
      */
     public long get(int key, long valueIfKeyNotFound) {
-        int i = binarySearch(mKeys, 0, mSize, key);
+        int i = SparseArray.binarySearch(mKeys, mSize, key);
 
         if (i < 0) {
             return valueIfKeyNotFound;
@@ -88,7 +95,7 @@ public class SparseLongArray implements Cloneable {
      * Removes the mapping from the specified key, if there was any.
      */
     public void delete(int key) {
-        int i = binarySearch(mKeys, 0, mSize, key);
+        int i = SparseArray.binarySearch(mKeys, mSize, key);
 
         if (i >= 0) {
             removeAt(i);
@@ -110,7 +117,7 @@ public class SparseLongArray implements Cloneable {
      * was one.
      */
     public void put(int key, long value) {
-        int i = binarySearch(mKeys, 0, mSize, key);
+        int i = SparseArray.binarySearch(mKeys, mSize, key);
 
         if (i >= 0) {
             mValues[i] = value;
@@ -164,7 +171,7 @@ public class SparseLongArray implements Cloneable {
      * key is not mapped.
      */
     public int indexOfKey(int key) {
-        return binarySearch(mKeys, 0, mSize, key);
+        return SparseArray.binarySearch(mKeys, mSize, key);
     }
 
     /**
@@ -222,24 +229,4 @@ public class SparseLongArray implements Cloneable {
         mKeys = nkeys;
         mValues = nvalues;
     }
-
-    private static int binarySearch(int[] a, int start, int len, long key) {
-        int high = start + len, low = start - 1, guess;
-
-        while (high - low > 1) {
-            guess = (high + low) / 2;
-
-            if (a[guess] < key)
-                low = guess;
-            else
-                high = guess;
-        }
-
-        if (high == start + len)
-            return ~(start + len);
-        else if (a[high] == key)
-            return high;
-        else
-            return ~high;
-    }
 }