Add LongSparseLongArray with tests. (dda73b5d) · 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();
			}
			}