New ArrayMap class.
This is a new kind of key/value mapping that stores its data
as an array, so it doesn't need to create an extra Entry object
for every mapping placed in to it. It is also optimized to reduce
memory overhead in other ways, by keeping the base object small,
being fairly aggressive about keeping the array data structures
small, etc.
There are some unit and performance tests dropped in to some
random places; they will need to be put somewhere else once I
decided what we are going to do with this for the next release
(for example if we make it public the unit tests should go in
to CTS).
Switch IntentResolver to using ArrayMap instead of HashMap.
Also get rid of a bunch of duplicate implementations of binarySearch,
and add an optimization to the various sparse arrays where you can
supply an explicit 0 capacity to prevent it from doing an initial
array allocation; use this new optimization in a few places where it
makes sense.
Change-Id: I01ef2764680f8ae49938e2a2ed40dc01606a056b
diff --git a/core/java/android/util/SparseIntArray.java b/core/java/android/util/SparseIntArray.java
index 8d11177..122f7f5 100644
--- a/core/java/android/util/SparseIntArray.java
+++ b/core/java/android/util/SparseIntArray.java
@@ -24,7 +24,6 @@
* than using a HashMap to map Integers to Integers.
*/
public class SparseIntArray implements Cloneable {
-
private int[] mKeys;
private int[] mValues;
private int mSize;
@@ -39,13 +38,19 @@
/**
* Creates a new SparseIntArray 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 SparseIntArray(int initialCapacity) {
- initialCapacity = ArrayUtils.idealIntArraySize(initialCapacity);
-
- mKeys = new int[initialCapacity];
- mValues = new int[initialCapacity];
+ if (initialCapacity == 0) {
+ mKeys = SparseArray.EMPTY_INTS;
+ mValues = SparseArray.EMPTY_INTS;
+ } else {
+ initialCapacity = ArrayUtils.idealIntArraySize(initialCapacity);
+ mKeys = new int[initialCapacity];
+ mValues = new int[initialCapacity];
+ }
mSize = 0;
}
@@ -75,7 +80,7 @@
* if no such mapping has been made.
*/
public int get(int key, int valueIfKeyNotFound) {
- int i = binarySearch(mKeys, 0, mSize, key);
+ int i = SparseArray.binarySearch(mKeys, mSize, key);
if (i < 0) {
return valueIfKeyNotFound;
@@ -88,7 +93,7 @@
* 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 +115,7 @@
* was one.
*/
public void put(int key, int value) {
- int i = binarySearch(mKeys, 0, mSize, key);
+ int i = SparseArray.binarySearch(mKeys, mSize, key);
if (i >= 0) {
mValues[i] = value;
@@ -175,7 +180,7 @@
* key is not mapped.
*/
public int indexOfKey(int key) {
- return binarySearch(mKeys, 0, mSize, key);
+ return SparseArray.binarySearch(mKeys, mSize, key);
}
/**
@@ -230,24 +235,4 @@
mValues[pos] = value;
mSize = pos + 1;
}
-
- private static int binarySearch(int[] a, int start, int len, int 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;
- }
}