Merge "Add LongSparseLongArray with tests." (e95724ae) · Commits · e / os / android_frameworks_base

core/java/android/util/LongSparseLongArray.java

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		/*
		* Copyright (C) 2007 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.util;

		import com.android.internal.util.ArrayUtils;

		import java.util.Arrays;

		/**
		* Map of {@code long} to {@code long}. Unlike a normal array of longs, there
		* can be gaps in the indices. It is intended to be more efficient than using a
		* {@code HashMap}.
		*
		* @hide
		*/
		public class LongSparseLongArray implements Cloneable {
		private long[] mKeys;
		private long[] mValues;
		private int mSize;

		/**
		* Creates a new SparseLongArray containing no mappings.
		*/
		public LongSparseLongArray() {
		this(10);
		}

		/**
		* Creates a new SparseLongArray containing no mappings that will not
		* require any additional memory allocation to store the specified
		* number of mappings.
		*/
		public LongSparseLongArray(int initialCapacity) {
		initialCapacity = ArrayUtils.idealLongArraySize(initialCapacity);

		mKeys = new long[initialCapacity];
		mValues = new long[initialCapacity];
		mSize = 0;
		}

		@Override
		public LongSparseLongArray clone() {
		LongSparseLongArray clone = null;
		try {
		clone = (LongSparseLongArray) super.clone();
		clone.mKeys = mKeys.clone();
		clone.mValues = mValues.clone();
		} catch (CloneNotSupportedException cnse) {
		/* ignore */
		}
		return clone;
		}

		/**
		* Gets the long mapped from the specified key, or <code>0</code>
		* if no such mapping has been made.
		*/
		public long get(long key) {
		return get(key, 0);
		}

		/**
		* Gets the long mapped from the specified key, or the specified value
		* if no such mapping has been made.
		*/
		public long get(long key, long valueIfKeyNotFound) {
		int i = Arrays.binarySearch(mKeys, 0, mSize, key);

		if (i < 0) {
		return valueIfKeyNotFound;
		} else {
		return mValues[i];
		}
		}

		/**
		* Removes the mapping from the specified key, if there was any.
		*/
		public void delete(long key) {
		int i = Arrays.binarySearch(mKeys, 0, mSize, key);

		if (i >= 0) {
		removeAt(i);
		}
		}

		/**
		* Removes the mapping at the given index.
		*/
		public void removeAt(int index) {
		System.arraycopy(mKeys, index + 1, mKeys, index, mSize - (index + 1));
		System.arraycopy(mValues, index + 1, mValues, index, mSize - (index + 1));
		mSize--;
		}

		/**
		* Adds a mapping from the specified key to the specified value,
		* replacing the previous mapping from the specified key if there
		* was one.
		*/
		public void put(long key, long value) {
		int i = Arrays.binarySearch(mKeys, 0, mSize, key);

		if (i >= 0) {
		mValues[i] = value;
		} else {
		i = ~i;

		if (mSize >= mKeys.length) {
		growKeyAndValueArrays(mSize + 1);
		}

		if (mSize - i != 0) {
		System.arraycopy(mKeys, i, mKeys, i + 1, mSize - i);
		System.arraycopy(mValues, i, mValues, i + 1, mSize - i);
		}

		mKeys[i] = key;
		mValues[i] = value;
		mSize++;
		}
		}

		/**
		* Returns the number of key-value mappings that this SparseIntArray
		* currently stores.
		*/
		public int size() {
		return mSize;
		}

		/**
		* Given an index in the range <code>0...size()-1</code>, returns
		* the key from the <code>index</code>th key-value mapping that this
		* SparseLongArray stores.
		*/
		public long keyAt(int index) {
		return mKeys[index];
		}

		/**
		* Given an index in the range <code>0...size()-1</code>, returns
		* the value from the <code>index</code>th key-value mapping that this
		* SparseLongArray stores.
		*/
		public long valueAt(int index) {
		return mValues[index];
		}

		/**
		* Returns the index for which {@link #keyAt} would return the
		* specified key, or a negative number if the specified
		* key is not mapped.
		*/
		public int indexOfKey(long key) {
		return Arrays.binarySearch(mKeys, 0, mSize, key);
		}

		/**
		* Returns an index for which {@link #valueAt} would return the
		* specified key, or a negative number if no keys map to the
		* specified value.
		* Beware that this is a linear search, unlike lookups by key,
		* and that multiple keys can map to the same value and this will
		* find only one of them.
		*/
		public int indexOfValue(long value) {
		for (int i = 0; i < mSize; i++)
		if (mValues[i] == value)
		return i;

		return -1;
		}

		/**
		* Removes all key-value mappings from this SparseIntArray.
		*/
		public void clear() {
		mSize = 0;
		}

		/**
		* Puts a key/value pair into the array, optimizing for the case where
		* the key is greater than all existing keys in the array.
		*/
		public void append(long key, long value) {
		if (mSize != 0 && key <= mKeys[mSize - 1]) {
		put(key, value);
		return;
		}

		int pos = mSize;
		if (pos >= mKeys.length) {
		growKeyAndValueArrays(pos + 1);
		}

		mKeys[pos] = key;
		mValues[pos] = value;
		mSize = pos + 1;
		}

		private void growKeyAndValueArrays(int minNeededSize) {
		int n = ArrayUtils.idealLongArraySize(minNeededSize);

		long[] nkeys = new long[n];
		long[] nvalues = new long[n];

		System.arraycopy(mKeys, 0, nkeys, 0, mKeys.length);
		System.arraycopy(mValues, 0, nvalues, 0, mValues.length);

		mKeys = nkeys;
		mValues = nvalues;
		}
		}

core/tests/coretests/src/android/util/LongSparseLongArrayTest.java

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		/*
		* Copyright (C) 2007 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.util;

		import junit.framework.TestCase;

		import java.util.HashMap;
		import java.util.Iterator;
		import java.util.Map;
		import java.util.Random;

		/**
		* Tests for {@link LongSparseLongArray}.
		*/
		public class LongSparseLongArrayTest extends TestCase {
		private static final String TAG = "LongSparseLongArrayTest";

		public void testSimplePut() throws Exception {
		final LongSparseLongArray array = new LongSparseLongArray(5);
		for (int i = 0; i < 48; i++) {
		final long value = 1 << i;
		array.put(value, value);
		}
		for (int i = 0; i < 48; i++) {
		final long value = 1 << i;
		assertEquals(value, array.get(value, -1));
		assertEquals(-1, array.get(-value, -1));
		}
		}

		public void testSimplePutBackwards() throws Exception {
		final LongSparseLongArray array = new LongSparseLongArray(5);
		for (int i = 47; i >= 0; i--) {
		final long value = 1 << i;
		array.put(value, value);
		}
		for (int i = 0; i < 48; i++) {
		final long value = 1 << i;
		assertEquals(value, array.get(value, -1));
		assertEquals(-1, array.get(-value, -1));
		}
		}

		public void testMiddleInsert() throws Exception {
		final LongSparseLongArray array = new LongSparseLongArray(5);
		for (int i = 0; i < 48; i++) {
		final long value = 1 << i;
		array.put(value, value);
		}
		final long special = (1 << 24) + 5;
		array.put(special, 1024);
		for (int i = 0; i < 48; i++) {
		final long value = 1 << i;
		assertEquals(value, array.get(value, -1));
		assertEquals(-1, array.get(-value, -1));
		}
		assertEquals(1024, array.get(special, -1));
		}

		public void testFuzz() throws Exception {
		final Random r = new Random();

		final HashMap<Long, Long> map = new HashMap<Long, Long>();
		final LongSparseLongArray array = new LongSparseLongArray(r.nextInt(128));

		for (int i = 0; i < 10240; i++) {
		if (r.nextBoolean()) {
		final long key = r.nextLong();
		final long value = r.nextLong();
		map.put(key, value);
		array.put(key, value);
		}
		if (r.nextBoolean() && map.size() > 0) {
		final int index = r.nextInt(map.size());
		final long key = getKeyAtIndex(map, index);
		map.remove(key);
		array.delete(key);
		}
		}

		Log.d(TAG, "verifying a map with " + map.size() + " entries");

		for (Map.Entry<Long, Long> e : map.entrySet()) {
		final long key = e.getKey();
		final long value = e.getValue();
		assertEquals(value, array.get(key));
		}
		}

		private static <E> E getKeyAtIndex(Map<E, ?> map, int index) {
		final Iterator<E> keys = map.keySet().iterator();
		for (int i = 0; i < index; i++) {
		keys.next();
		}
		return keys.next();
		}
		}