Add IdentityHashMap, improve distribution of identityHashCode

Add IdentityHashMap, improve distribution of identityHashCode
This commit is contained in:
Michele Comignano 2018-05-05 21:05:22 +02:00 committed by Alexey Andreev
parent ff07b28bee
commit c11b868c0b
3 changed files with 741 additions and 8 deletions

View File

@ -0,0 +1,621 @@
/*
* Copyright 2014 Alexey Andreev.
*
* 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.
*/
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.teavm.classlib.java.util;
import java.util.Arrays;
import java.util.ConcurrentModificationException;
import org.teavm.classlib.java.io.TSerializable;
import org.teavm.classlib.java.lang.TCloneNotSupportedException;
import org.teavm.classlib.java.lang.TCloneable;
import org.teavm.classlib.java.lang.TIllegalArgumentException;
import org.teavm.classlib.java.lang.TIllegalStateException;
import org.teavm.classlib.java.lang.TObject;
import org.teavm.interop.Rename;
public class TIdentityHashMap<K, V> extends TAbstractMap<K, V> implements TCloneable, TSerializable {
transient int elementCount;
transient HashEntry<K, V>[] elementData;
transient int modCount;
private static final int DEFAULT_SIZE = 16;
final float loadFactor;
int threshold;
static class HashEntry<K, V> extends TMapEntry<K, V> {
final int origKeyHash;
HashEntry<K, V> next;
HashEntry(K theKey, int hash) {
super(theKey, null);
this.origKeyHash = hash;
}
HashEntry(K theKey, V theValue) {
super(theKey, theValue);
origKeyHash = theKey == null ? 0 : computeHashCode(theKey);
}
@Override
@SuppressWarnings("unchecked")
public Object clone() {
HashEntry<K, V> entry = (HashEntry<K, V>) super.clone();
if (next != null) {
entry.next = (HashEntry<K, V>) next.clone();
}
return entry;
}
}
private static class AbstractMapIterator<K, V> {
private int position;
int expectedModCount;
HashEntry<K, V> futureEntry;
HashEntry<K, V> currentEntry;
HashEntry<K, V> prevEntry;
final TIdentityHashMap<K, V> associatedMap;
AbstractMapIterator(TIdentityHashMap<K, V> hm) {
associatedMap = hm;
expectedModCount = hm.modCount;
futureEntry = null;
}
public boolean hasNext() {
if (futureEntry != null) {
return true;
}
while (position < associatedMap.elementData.length) {
if (associatedMap.elementData[position] == null) {
position++;
} else {
return true;
}
}
return false;
}
final void checkConcurrentMod() throws ConcurrentModificationException {
if (expectedModCount != associatedMap.modCount) {
throw new TConcurrentModificationException();
}
}
final void makeNext() {
checkConcurrentMod();
if (!hasNext()) {
throw new TNoSuchElementException();
}
if (futureEntry == null) {
currentEntry = associatedMap.elementData[position++];
futureEntry = currentEntry.next;
prevEntry = null;
} else {
if (currentEntry != null) {
prevEntry = currentEntry;
}
currentEntry = futureEntry;
futureEntry = futureEntry.next;
}
}
public final void remove() {
checkConcurrentMod();
if (currentEntry == null) {
throw new TIllegalStateException();
}
if (prevEntry == null) {
int index = currentEntry.origKeyHash & (associatedMap.elementData.length - 1);
associatedMap.elementData[index] = associatedMap.elementData[index].next;
} else {
prevEntry.next = currentEntry.next;
}
currentEntry = null;
expectedModCount++;
associatedMap.modCount++;
associatedMap.elementCount--;
}
}
private static class EntryIterator<K, V> extends AbstractMapIterator<K, V>
implements TIterator<Entry<K, V>> {
EntryIterator(TIdentityHashMap<K, V> map) {
super(map);
}
@Override
public Entry<K, V> next() {
makeNext();
return currentEntry;
}
}
private static class KeyIterator<K, V> extends AbstractMapIterator<K, V> implements TIterator<K> {
KeyIterator(TIdentityHashMap<K, V> map) {
super(map);
}
@Override
public K next() {
makeNext();
return currentEntry.key;
}
}
private static class ValueIterator<K, V> extends AbstractMapIterator<K, V> implements TIterator<V> {
ValueIterator(TIdentityHashMap<K, V> map) {
super(map);
}
@Override
public V next() {
makeNext();
return currentEntry.value;
}
}
static class HashMapEntrySet<K, V> extends TAbstractSet<Entry<K, V>> {
private final TIdentityHashMap<K, V> associatedMap;
public HashMapEntrySet(TIdentityHashMap<K, V> hm) {
associatedMap = hm;
}
TIdentityHashMap<K, V> hashMap() {
return associatedMap;
}
@Override
public int size() {
return associatedMap.elementCount;
}
@Override
public void clear() {
associatedMap.clear();
}
@Override
public boolean remove(Object object) {
if (object instanceof TMap.Entry) {
Entry<?, ?> oEntry = (Entry<?, ?>) object;
Entry<K, V> entry = associatedMap.getEntry(oEntry.getKey());
if (valuesEq(entry, oEntry)) {
associatedMap.removeEntry(entry);
return true;
}
}
return false;
}
@Override
public boolean contains(Object object) {
if (object instanceof TMap.Entry) {
Entry<?, ?> oEntry = (Entry<?, ?>) object;
Entry<K, V> entry = associatedMap.getEntry(oEntry.getKey());
return valuesEq(entry, oEntry);
}
return false;
}
private static boolean valuesEq(Entry<?, ?> entry, Entry<?, ?> oEntry) {
return entry != null
&& (entry.getValue() == null
? oEntry.getValue() == null
: areSameValues(entry.getValue(), oEntry.getValue()));
}
@Override
public TIterator<Entry<K, V>> iterator() {
return new EntryIterator<>(associatedMap);
}
}
@SuppressWarnings("unchecked")
HashEntry<K, V>[] newElementArray(int s) {
return new HashEntry[s];
}
public TIdentityHashMap() {
this(DEFAULT_SIZE);
}
public TIdentityHashMap(int capacity) {
this(capacity, 0.75f); // default load factor of 0.75
}
private static int calculateCapacity(int x) {
if (x >= 1 << 30) {
return 1 << 30;
}
if (x == 0) {
return 16;
}
x = x - 1;
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
return x + 1;
}
/**
* Constructs a new {@code HashMap} instance with the specified capacity and
* load factor.
*
* @param capacity
* the initial capacity of this hash map.
* @param loadFactor
* the initial load factor.
* @throws IllegalArgumentException
* when the capacity is less than zero or the load factor is
* less or equal to zero.
*/
public TIdentityHashMap(int capacity, float loadFactor) {
if (capacity >= 0 && loadFactor > 0) {
capacity = calculateCapacity(capacity);
elementCount = 0;
elementData = newElementArray(capacity);
this.loadFactor = loadFactor;
computeThreshold();
} else {
throw new TIllegalArgumentException();
}
}
public TIdentityHashMap(TMap<? extends K, ? extends V> map) {
this(calculateCapacity(map.size()));
putAllImpl(map);
}
@Override
public void clear() {
if (elementCount > 0) {
elementCount = 0;
Arrays.fill(elementData, null);
modCount++;
}
}
@Rename("clone")
@SuppressWarnings("unchecked")
public TObject clone0() {
try {
TIdentityHashMap<K, V> map = (TIdentityHashMap<K, V>) super.clone();
map.elementCount = 0;
map.elementData = newElementArray(elementData.length);
map.putAll(this);
return map;
} catch (TCloneNotSupportedException e) {
return null;
}
}
private void computeThreshold() {
threshold = (int) (elementData.length * loadFactor);
}
@Override
public boolean containsKey(Object key) {
HashEntry<K, V> m = getEntry(key);
return m != null;
}
@Override
public boolean containsValue(Object value) {
if (value != null) {
for (int i = 0; i < elementData.length; i++) {
HashEntry<K, V> entry = elementData[i];
while (entry != null) {
if (areSameValues(value, entry.value)) {
return true;
}
entry = entry.next;
}
}
} else {
for (int i = 0; i < elementData.length; i++) {
HashEntry<K, V> entry = elementData[i];
while (entry != null) {
if (entry.value == null) {
return true;
}
entry = entry.next;
}
}
}
return false;
}
@Override
public TSet<Entry<K, V>> entrySet() {
return new HashMapEntrySet<>(this);
}
@Override
public V get(Object key) {
HashEntry<K, V> m = getEntry(key);
if (m != null) {
return m.value;
}
return null;
}
final HashEntry<K, V> getEntry(Object key) {
HashEntry<K, V> m;
if (key == null) {
m = findNullKeyEntry();
} else {
int hash = computeHashCode(key);
int index = hash & (elementData.length - 1);
m = findNonNullKeyEntry(key, index, hash);
}
return m;
}
final HashEntry<K, V> findNonNullKeyEntry(Object key, int index, int keyHash) {
HashEntry<K, V> m = elementData[index];
while (m != null
&& (m.origKeyHash != keyHash || !areSameKeys(key, m.key))) {
m = m.next;
}
return m;
}
final HashEntry<K, V> findNullKeyEntry() {
HashEntry<K, V> m = elementData[0];
while (m != null && m.key != null) {
m = m.next;
}
return m;
}
@Override
public boolean isEmpty() {
return elementCount == 0;
}
@Override
public TSet<K> keySet() {
if (cachedKeySet == null) {
cachedKeySet = new TAbstractSet<K>() {
@Override public boolean contains(Object object) {
return containsKey(object);
}
@Override public int size() {
return TIdentityHashMap.this.size();
}
@Override public void clear() {
TIdentityHashMap.this.clear();
}
@Override public boolean remove(Object key) {
HashEntry<K, V> entry = TIdentityHashMap.this.removeEntry(key);
return entry != null;
}
@Override public TIterator<K> iterator() {
return new KeyIterator<>(TIdentityHashMap.this);
}
};
}
return cachedKeySet;
}
@Override
public V put(K key, V value) {
return putImpl(key, value);
}
V putImpl(K key, V value) {
HashEntry<K, V> entry;
if (key == null) {
entry = findNullKeyEntry();
if (entry == null) {
modCount++;
entry = createHashedEntry(null, 0, 0);
if (++elementCount > threshold) {
rehash();
}
}
} else {
int hash = computeHashCode(key);
int index = hash & (elementData.length - 1);
entry = findNonNullKeyEntry(key, index, hash);
if (entry == null) {
modCount++;
entry = createHashedEntry(key, index, hash);
if (++elementCount > threshold) {
rehash();
}
}
}
V result = entry.value;
entry.value = value;
return result;
}
HashEntry<K, V> createEntry(K key, int index, V value) {
HashEntry<K, V> entry = new HashEntry<>(key, value);
entry.next = elementData[index];
elementData[index] = entry;
return entry;
}
HashEntry<K, V> createHashedEntry(K key, int index, int hash) {
HashEntry<K, V> entry = new HashEntry<>(key, hash);
entry.next = elementData[index];
elementData[index] = entry;
return entry;
}
@Override
public void putAll(TMap<? extends K, ? extends V> map) {
if (!map.isEmpty()) {
putAllImpl(map);
}
}
private void putAllImpl(TMap<? extends K, ? extends V> map) {
int capacity = elementCount + map.size();
if (capacity > threshold) {
rehash(capacity);
}
for (TIterator<? extends Entry<? extends K, ? extends V>> iter = map.entrySet().iterator();
iter.hasNext();) {
Entry<? extends K, ? extends V> entry = iter.next();
putImpl(entry.getKey(), entry.getValue());
}
}
void rehash(int capacity) {
int length = calculateCapacity(capacity == 0 ? 1 : capacity << 1);
HashEntry<K, V>[] newData = newElementArray(length);
for (int i = 0; i < elementData.length; i++) {
HashEntry<K, V> entry = elementData[i];
elementData[i] = null;
while (entry != null) {
int index = entry.origKeyHash & (length - 1);
HashEntry<K, V> next = entry.next;
entry.next = newData[index];
newData[index] = entry;
entry = next;
}
}
elementData = newData;
computeThreshold();
}
void rehash() {
rehash(elementData.length);
}
@Override
public V remove(Object key) {
HashEntry<K, V> entry = removeEntry(key);
if (entry != null) {
return entry.value;
}
return null;
}
final void removeEntry(HashEntry<K, V> entry) {
int index = entry.origKeyHash & (elementData.length - 1);
HashEntry<K, V> m = elementData[index];
if (m == entry) {
elementData[index] = entry.next;
} else {
while (m.next != entry) {
m = m.next;
}
m.next = entry.next;
}
modCount++;
elementCount--;
}
final HashEntry<K, V> removeEntry(Object key) {
int index = 0;
HashEntry<K, V> entry;
HashEntry<K, V> last = null;
if (key != null) {
int hash = computeHashCode(key);
index = hash & (elementData.length - 1);
entry = elementData[index];
while (entry != null && !(entry.origKeyHash == hash && areSameKeys(key, entry.key))) {
last = entry;
entry = entry.next;
}
} else {
entry = elementData[0];
while (entry != null && entry.key != null) {
last = entry;
entry = entry.next;
}
}
if (entry == null) {
return null;
}
if (last == null) {
elementData[index] = entry.next;
} else {
last.next = entry.next;
}
modCount++;
elementCount--;
return entry;
}
@Override
public int size() {
return elementCount;
}
@Override
public TCollection<V> values() {
if (cachedValues == null) {
cachedValues = new TAbstractCollection<V>() {
@Override public boolean contains(Object object) {
return containsValue(object);
}
@Override public int size() {
return TIdentityHashMap.this.size();
}
@Override public void clear() {
TIdentityHashMap.this.clear();
}
@Override public TIterator<V> iterator() {
return new ValueIterator<>(TIdentityHashMap.this);
}
};
}
return cachedValues;
}
static int computeHashCode(Object key) {
return System.identityHashCode(key);
}
static boolean areSameKeys(Object key1, Object key2) {
return key1 == key2;
}
static boolean areSameValues(Object value1, Object value2) {
return value1 == value2;
}
}

View File

@ -15,15 +15,14 @@
*/ */
"use strict"; "use strict";
var $rt_global = this; var $rt_global = this;
var $rt_lastObjectId = 1; var $rt_seed = 2463534242;
function $rt_nextId() { function $rt_nextId() {
var current = $rt_lastObjectId; var x = $rt_seed;
var next = (current + 1) | 0; x ^= x << 13;
if (next === 0) { x ^= x >> 17;
next = (next + 1) | 0; x ^= x << 5;
} $rt_seed = x;
$rt_lastObjectId = next; return x;
return current;
} }
function $rt_compare(a, b) { function $rt_compare(a, b) {
return a > b ? 1 : a < b ? -1 : 0; return a > b ? 1 : a < b ? -1 : 0;

View File

@ -0,0 +1,113 @@
/*
* Copyright 2014 Alexey Andreev.
*
* 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.
*/
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.teavm.classlib.java.util;
import static org.junit.Assert.assertEquals;
import java.util.IdentityHashMap;
import java.util.Map;
import java.util.Objects;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.teavm.junit.TeaVMTestRunner;
@RunWith(TeaVMTestRunner.class)
public class IdentityHashMapTest {
@Test
public void sameObjectOnce() {
Map<Object, Object> m = new IdentityHashMap<>();
Object key = new Object();
m.put(key, "val1");
m.put(key, "val2");
assertEquals(1, m.keySet().size());
}
@Test
public void twoObjectsTwice() {
Map<Object, Object> m = new IdentityHashMap<>();
Object key1 = new Object();
Object key2 = new Object();
m.put(key1, "val1");
m.put(key2, "val2");
assertEquals(2, m.size());
assertEquals("val1", m.get(key1));
assertEquals("val2", m.get(key2));
}
@Test
public void twoObjectsWithSameHashCode() {
Map<A, Object> m = new IdentityHashMap<>();
A key1 = new A("ciao");
A key2 = new A("ciao");
m.put(key1, "val1");
m.put(key2, "val2");
assertEquals(2, m.size());
assertEquals("val1", m.get(key1));
assertEquals("val2", m.get(key2));
}
@Test
public void nullKeyAllowed() {
Map<String, String> m = new IdentityHashMap<>();
m.put(null, "val1");
m.put(null, "val2");
assertEquals(1, m.size());
assertEquals("val2", m.get(null));
}
static class A {
public A(String b) {
this.b = b;
}
private String b;
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
A a = (A) o;
return Objects.equals(b, a.b);
}
@Override
public int hashCode() {
return Objects.hash(b);
}
}
}