it.unimi.dsi.fastutil.objects.Reference2ObjectOpenHashMap Maven / Gradle / Ivy
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/*
* Copyright (C) 2002-2017 Sebastiano Vigna
*
* 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 it.unimi.dsi.fastutil.objects;
import it.unimi.dsi.fastutil.Hash;
import it.unimi.dsi.fastutil.HashCommon;
import static it.unimi.dsi.fastutil.HashCommon.arraySize;
import static it.unimi.dsi.fastutil.HashCommon.maxFill;
import java.util.Map;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.function.Consumer;
import it.unimi.dsi.fastutil.objects.ObjectCollection;
import it.unimi.dsi.fastutil.objects.AbstractObjectCollection;
import it.unimi.dsi.fastutil.objects.AbstractObjectSet;
import it.unimi.dsi.fastutil.objects.ObjectIterator;
/**
* A type-specific hash map with a fast, small-footprint implementation.
*
*
* Instances of this class use a hash table to represent a map. The table is
* filled up to a specified load factor, and then doubled in size to
* accommodate new entries. If the table is emptied below one fourth of
* the load factor, it is halved in size; however, the table is never reduced to
* a size smaller than that at creation time: this approach makes it possible to
* create maps with a large capacity in which insertions and deletions do not
* cause immediately rehashing. Moreover, halving is not performed when deleting
* entries from an iterator, as it would interfere with the iteration process.
*
*
* Note that {@link #clear()} does not modify the hash table size. Rather, a
* family of {@linkplain #trim() trimming methods} lets you control the size of
* the table; this is particularly useful if you reuse instances of this class.
*
* @see Hash
* @see HashCommon
*/
public class Reference2ObjectOpenHashMap extends AbstractReference2ObjectMap
implements
java.io.Serializable,
Cloneable,
Hash {
private static final long serialVersionUID = 0L;
private static final boolean ASSERTS = false;
/** The array of keys. */
protected transient K[] key;
/** The array of values. */
protected transient V[] value;
/** The mask for wrapping a position counter. */
protected transient int mask;
/** Whether this map contains the key zero. */
protected transient boolean containsNullKey;
/** The current table size. */
protected transient int n;
/**
* Threshold after which we rehash. It must be the table size times {@link #f}.
*/
protected transient int maxFill;
/**
* We never resize below this threshold, which is the construction-time {#n}.
*/
protected final transient int minN;
/** Number of entries in the set (including the key zero, if present). */
protected int size;
/** The acceptable load factor. */
protected final float f;
/** Cached set of entries. */
protected transient FastEntrySet entries;
/** Cached set of keys. */
protected transient ReferenceSet keys;
/** Cached collection of values. */
protected transient ObjectCollection values;
/**
* Creates a new hash map.
*
*
* The actual table size will be the least power of two greater than
* {@code expected}/{@code f}.
*
* @param expected
* the expected number of elements in the hash map.
* @param f
* the load factor.
*/
@SuppressWarnings("unchecked")
public Reference2ObjectOpenHashMap(final int expected, final float f) {
if (f <= 0 || f > 1)
throw new IllegalArgumentException("Load factor must be greater than 0 and smaller than or equal to 1");
if (expected < 0)
throw new IllegalArgumentException("The expected number of elements must be nonnegative");
this.f = f;
minN = n = arraySize(expected, f);
mask = n - 1;
maxFill = maxFill(n, f);
key = (K[]) new Object[n + 1];
value = (V[]) new Object[n + 1];
}
/**
* Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
*
* @param expected
* the expected number of elements in the hash map.
*/
public Reference2ObjectOpenHashMap(final int expected) {
this(expected, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash map with initial expected
* {@link Hash#DEFAULT_INITIAL_SIZE} entries and
* {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
*/
public Reference2ObjectOpenHashMap() {
this(DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash map copying a given one.
*
* @param m
* a {@link Map} to be copied into the new hash map.
* @param f
* the load factor.
*/
public Reference2ObjectOpenHashMap(final Map m, final float f) {
this(m.size(), f);
putAll(m);
}
/**
* Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
* copying a given one.
*
* @param m
* a {@link Map} to be copied into the new hash map.
*/
public Reference2ObjectOpenHashMap(final Map m) {
this(m, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash map copying a given type-specific one.
*
* @param m
* a type-specific map to be copied into the new hash map.
* @param f
* the load factor.
*/
public Reference2ObjectOpenHashMap(final Reference2ObjectMap m, final float f) {
this(m.size(), f);
putAll(m);
}
/**
* Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
* copying a given type-specific one.
*
* @param m
* a type-specific map to be copied into the new hash map.
*/
public Reference2ObjectOpenHashMap(final Reference2ObjectMap m) {
this(m, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash map using the elements of two parallel arrays.
*
* @param k
* the array of keys of the new hash map.
* @param v
* the array of corresponding values in the new hash map.
* @param f
* the load factor.
* @throws IllegalArgumentException
* if {@code k} and {@code v} have different lengths.
*/
public Reference2ObjectOpenHashMap(final K[] k, final V[] v, final float f) {
this(k.length, f);
if (k.length != v.length)
throw new IllegalArgumentException(
"The key array and the value array have different lengths (" + k.length + " and " + v.length + ")");
for (int i = 0; i < k.length; i++)
this.put(k[i], v[i]);
}
/**
* Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
* using the elements of two parallel arrays.
*
* @param k
* the array of keys of the new hash map.
* @param v
* the array of corresponding values in the new hash map.
* @throws IllegalArgumentException
* if {@code k} and {@code v} have different lengths.
*/
public Reference2ObjectOpenHashMap(final K[] k, final V[] v) {
this(k, v, DEFAULT_LOAD_FACTOR);
}
private int realSize() {
return containsNullKey ? size - 1 : size;
}
private void ensureCapacity(final int capacity) {
final int needed = arraySize(capacity, f);
if (needed > n)
rehash(needed);
}
private void tryCapacity(final long capacity) {
final int needed = (int) Math.min(1 << 30,
Math.max(2, HashCommon.nextPowerOfTwo((long) Math.ceil(capacity / f))));
if (needed > n)
rehash(needed);
}
private V removeEntry(final int pos) {
final V oldValue = value[pos];
value[pos] = null;
size--;
shiftKeys(pos);
if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE)
rehash(n / 2);
return oldValue;
}
private V removeNullEntry() {
containsNullKey = false;
key[n] = null;
final V oldValue = value[n];
value[n] = null;
size--;
if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE)
rehash(n / 2);
return oldValue;
}
@Override
public void putAll(Map m) {
if (f <= .5)
ensureCapacity(m.size()); // The resulting map will be sized for m.size() elements
else
tryCapacity(size() + m.size()); // The resulting map will be tentatively sized for size() + m.size()
// elements
super.putAll(m);
}
@SuppressWarnings("unchecked")
private int find(final K k) {
if (((k) == (null)))
return containsNullKey ? n : -(n + 1);
K curr;
final K[] key = this.key;
int pos;
// The starting point.
if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(k))) & mask]) == (null)))
return -(pos + 1);
if (((k) == (curr)))
return pos;
// There's always an unused entry.
while (true) {
if (((curr = key[pos = (pos + 1) & mask]) == (null)))
return -(pos + 1);
if (((k) == (curr)))
return pos;
}
}
private void insert(final int pos, final K k, final V v) {
if (pos == n)
containsNullKey = true;
key[pos] = k;
value[pos] = v;
if (size++ >= maxFill)
rehash(arraySize(size + 1, f));
if (ASSERTS)
checkTable();
}
@Override
public V put(final K k, final V v) {
final int pos = find(k);
if (pos < 0) {
insert(-pos - 1, k, v);
return defRetValue;
}
final V oldValue = value[pos];
value[pos] = v;
return oldValue;
}
/**
* Shifts left entries with the specified hash code, starting at the specified
* position, and empties the resulting free entry.
*
* @param pos
* a starting position.
*/
protected final void shiftKeys(int pos) {
// Shift entries with the same hash.
int last, slot;
K curr;
final K[] key = this.key;
for (;;) {
pos = ((last = pos) + 1) & mask;
for (;;) {
if (((curr = key[pos]) == (null))) {
key[last] = (null);
value[last] = null;
return;
}
slot = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(curr))) & mask;
if (last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos)
break;
pos = (pos + 1) & mask;
}
key[last] = curr;
value[last] = value[pos];
}
}
@Override
@SuppressWarnings("unchecked")
public V remove(final Object k) {
if ((((K) k) == (null))) {
if (containsNullKey)
return removeNullEntry();
return defRetValue;
}
K curr;
final K[] key = this.key;
int pos;
// The starting point.
if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(k))) & mask]) == (null)))
return defRetValue;
if (((k) == (curr)))
return removeEntry(pos);
while (true) {
if (((curr = key[pos = (pos + 1) & mask]) == (null)))
return defRetValue;
if (((k) == (curr)))
return removeEntry(pos);
}
}
@Override
@SuppressWarnings("unchecked")
public V get(final Object k) {
if ((((K) k) == (null)))
return containsNullKey ? value[n] : defRetValue;
K curr;
final K[] key = this.key;
int pos;
// The starting point.
if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(k))) & mask]) == (null)))
return defRetValue;
if (((k) == (curr)))
return value[pos];
// There's always an unused entry.
while (true) {
if (((curr = key[pos = (pos + 1) & mask]) == (null)))
return defRetValue;
if (((k) == (curr)))
return value[pos];
}
}
@Override
@SuppressWarnings("unchecked")
public boolean containsKey(final Object k) {
if ((((K) k) == (null)))
return containsNullKey;
K curr;
final K[] key = this.key;
int pos;
// The starting point.
if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(k))) & mask]) == (null)))
return false;
if (((k) == (curr)))
return true;
// There's always an unused entry.
while (true) {
if (((curr = key[pos = (pos + 1) & mask]) == (null)))
return false;
if (((k) == (curr)))
return true;
}
}
@Override
public boolean containsValue(final Object v) {
final V value[] = this.value;
final K key[] = this.key;
if (containsNullKey && java.util.Objects.equals(value[n], v))
return true;
for (int i = n; i-- != 0;)
if (!((key[i]) == (null)) && java.util.Objects.equals(value[i], v))
return true;
return false;
}
/*
* Removes all elements from this map.
*
* To increase object reuse, this method does not change the table size. If
* you want to reduce the table size, you must use {@link #trim()}.
*
*/
@Override
public void clear() {
if (size == 0)
return;
size = 0;
containsNullKey = false;
Arrays.fill(key, (null));
Arrays.fill(value, null);
}
@Override
public int size() {
return size;
}
@Override
public boolean isEmpty() {
return size == 0;
}
/**
* The entry class for a hash map does not record key and value, but rather the
* position in the hash table of the corresponding entry. This is necessary so
* that calls to {@link java.util.Map.Entry#setValue(Object)} are reflected in
* the map
*/
final class MapEntry implements Reference2ObjectMap.Entry, Map.Entry {
// The table index this entry refers to, or -1 if this entry has been deleted.
int index;
MapEntry(final int index) {
this.index = index;
}
MapEntry() {
}
@Override
public K getKey() {
return key[index];
}
@Override
public V getValue() {
return value[index];
}
@Override
public V setValue(final V v) {
final V oldValue = value[index];
value[index] = v;
return oldValue;
}
@SuppressWarnings("unchecked")
@Override
public boolean equals(final Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry e = (Map.Entry) o;
return ((key[index]) == ((e.getKey()))) && java.util.Objects.equals(value[index], (e.getValue()));
}
@Override
public int hashCode() {
return (System.identityHashCode(key[index])) ^ ((value[index]) == null ? 0 : (value[index]).hashCode());
}
@Override
public String toString() {
return key[index] + "=>" + value[index];
}
}
/** An iterator over a hash map. */
private class MapIterator {
/**
* The index of the last entry returned, if positive or zero; initially,
* {@link #n}. If negative, the last entry returned was that of the key of index
* {@code - pos - 1} from the {@link #wrapped} list.
*/
int pos = n;
/**
* The index of the last entry that has been returned (more precisely, the value
* of {@link #pos} if {@link #pos} is positive, or {@link Integer#MIN_VALUE} if
* {@link #pos} is negative). It is -1 if either we did not return an entry yet,
* or the last returned entry has been removed.
*/
int last = -1;
/** A downward counter measuring how many entries must still be returned. */
int c = size;
/**
* A boolean telling us whether we should return the entry with the null key.
*/
boolean mustReturnNullKey = Reference2ObjectOpenHashMap.this.containsNullKey;
/**
* A lazily allocated list containing keys of entries that have wrapped around
* the table because of removals.
*/
ReferenceArrayList wrapped;
public boolean hasNext() {
return c != 0;
}
public int nextEntry() {
if (!hasNext())
throw new NoSuchElementException();
c--;
if (mustReturnNullKey) {
mustReturnNullKey = false;
return last = n;
}
final K key[] = Reference2ObjectOpenHashMap.this.key;
for (;;) {
if (--pos < 0) {
// We are just enumerating elements from the wrapped list.
last = Integer.MIN_VALUE;
final K k = wrapped.get(-pos - 1);
int p = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(k))) & mask;
while (!((k) == (key[p])))
p = (p + 1) & mask;
return p;
}
if (!((key[pos]) == (null)))
return last = pos;
}
}
/**
* Shifts left entries with the specified hash code, starting at the specified
* position, and empties the resulting free entry.
*
* @param pos
* a starting position.
*/
private void shiftKeys(int pos) {
// Shift entries with the same hash.
int last, slot;
K curr;
final K[] key = Reference2ObjectOpenHashMap.this.key;
for (;;) {
pos = ((last = pos) + 1) & mask;
for (;;) {
if (((curr = key[pos]) == (null))) {
key[last] = (null);
value[last] = null;
return;
}
slot = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(curr))) & mask;
if (last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos)
break;
pos = (pos + 1) & mask;
}
if (pos < last) { // Wrapped entry.
if (wrapped == null)
wrapped = new ReferenceArrayList<>(2);
wrapped.add(key[pos]);
}
key[last] = curr;
value[last] = value[pos];
}
}
public void remove() {
if (last == -1)
throw new IllegalStateException();
if (last == n) {
containsNullKey = false;
key[n] = null;
value[n] = null;
} else if (pos >= 0)
shiftKeys(last);
else {
// We're removing wrapped entries.
Reference2ObjectOpenHashMap.this.remove(wrapped.set(-pos - 1, null));
last = -1; // Note that we must not decrement size
return;
}
size--;
last = -1; // You can no longer remove this entry.
if (ASSERTS)
checkTable();
}
public int skip(final int n) {
int i = n;
while (i-- != 0 && hasNext())
nextEntry();
return n - i - 1;
}
}
private class EntryIterator extends MapIterator implements ObjectIterator> {
private MapEntry entry;
@Override
public MapEntry next() {
return entry = new MapEntry(nextEntry());
}
@Override
public void remove() {
super.remove();
entry.index = -1; // You cannot use a deleted entry.
}
}
private class FastEntryIterator extends MapIterator implements ObjectIterator> {
private final MapEntry entry = new MapEntry();
@Override
public MapEntry next() {
entry.index = nextEntry();
return entry;
}
}
private final class MapEntrySet extends AbstractObjectSet>
implements
FastEntrySet {
@Override
public ObjectIterator> iterator() {
return new EntryIterator();
}
@Override
public ObjectIterator> fastIterator() {
return new FastEntryIterator();
}
@Override
@SuppressWarnings("unchecked")
public boolean contains(final Object o) {
if (!(o instanceof Map.Entry))
return false;
final Map.Entry e = (Map.Entry) o;
final K k = ((K) e.getKey());
final V v = ((V) e.getValue());
if (((k) == (null)))
return Reference2ObjectOpenHashMap.this.containsNullKey && java.util.Objects.equals(value[n], v);
K curr;
final K[] key = Reference2ObjectOpenHashMap.this.key;
int pos;
// The starting point.
if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(k)))
& mask]) == (null)))
return false;
if (((k) == (curr)))
return java.util.Objects.equals(value[pos], v);
// There's always an unused entry.
while (true) {
if (((curr = key[pos = (pos + 1) & mask]) == (null)))
return false;
if (((k) == (curr)))
return java.util.Objects.equals(value[pos], v);
}
}
@Override
@SuppressWarnings("unchecked")
public boolean remove(final Object o) {
if (!(o instanceof Map.Entry))
return false;
final Map.Entry e = (Map.Entry) o;
final K k = ((K) e.getKey());
final V v = ((V) e.getValue());
if (((k) == (null))) {
if (containsNullKey && java.util.Objects.equals(value[n], v)) {
removeNullEntry();
return true;
}
return false;
}
K curr;
final K[] key = Reference2ObjectOpenHashMap.this.key;
int pos;
// The starting point.
if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(k)))
& mask]) == (null)))
return false;
if (((curr) == (k))) {
if (java.util.Objects.equals(value[pos], v)) {
removeEntry(pos);
return true;
}
return false;
}
while (true) {
if (((curr = key[pos = (pos + 1) & mask]) == (null)))
return false;
if (((curr) == (k))) {
if (java.util.Objects.equals(value[pos], v)) {
removeEntry(pos);
return true;
}
}
}
}
@Override
public int size() {
return size;
}
@Override
public void clear() {
Reference2ObjectOpenHashMap.this.clear();
}
/** {@inheritDoc} */
@Override
public void forEach(final Consumer> consumer) {
if (containsNullKey)
consumer.accept(new AbstractReference2ObjectMap.BasicEntry(key[n], value[n]));
for (int pos = n; pos-- != 0;)
if (!((key[pos]) == (null)))
consumer.accept(new AbstractReference2ObjectMap.BasicEntry(key[pos], value[pos]));
}
/** {@inheritDoc} */
@Override
public void fastForEach(final Consumer> consumer) {
final AbstractReference2ObjectMap.BasicEntry entry = new AbstractReference2ObjectMap.BasicEntry<>();
if (containsNullKey) {
entry.key = key[n];
entry.value = value[n];
consumer.accept(entry);
}
for (int pos = n; pos-- != 0;)
if (!((key[pos]) == (null))) {
entry.key = key[pos];
entry.value = value[pos];
consumer.accept(entry);
}
}
}
@Override
public FastEntrySet reference2ObjectEntrySet() {
if (entries == null)
entries = new MapEntrySet();
return entries;
}
/**
* An iterator on keys.
*
*
* We simply override the
* {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()}
* methods (and possibly their type-specific counterparts) so that they return
* keys instead of entries.
*/
private final class KeyIterator extends MapIterator implements ObjectIterator {
public KeyIterator() {
super();
}
@Override
public K next() {
return key[nextEntry()];
}
}
private final class KeySet extends AbstractReferenceSet {
@Override
public ObjectIterator iterator() {
return new KeyIterator();
}
/** {@inheritDoc} */
@Override
public void forEach(final Consumer consumer) {
if (containsNullKey)
consumer.accept(key[n]);
for (int pos = n; pos-- != 0;) {
final K k = key[pos];
if (!((k) == (null)))
consumer.accept(k);
}
}
@Override
public int size() {
return size;
}
@Override
public boolean contains(Object k) {
return containsKey(k);
}
@Override
public boolean remove(Object k) {
final int oldSize = size;
Reference2ObjectOpenHashMap.this.remove(k);
return size != oldSize;
}
@Override
public void clear() {
Reference2ObjectOpenHashMap.this.clear();
}
}
@Override
public ReferenceSet keySet() {
if (keys == null)
keys = new KeySet();
return keys;
}
/**
* An iterator on values.
*
*
* We simply override the
* {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()}
* methods (and possibly their type-specific counterparts) so that they return
* values instead of entries.
*/
private final class ValueIterator extends MapIterator implements ObjectIterator {
public ValueIterator() {
super();
}
@Override
public V next() {
return value[nextEntry()];
}
}
@Override
public ObjectCollection values() {
if (values == null)
values = new AbstractObjectCollection() {
@Override
public ObjectIterator iterator() {
return new ValueIterator();
}
@Override
public int size() {
return size;
}
@Override
public boolean contains(Object v) {
return containsValue(v);
}
@Override
public void clear() {
Reference2ObjectOpenHashMap.this.clear();
}
/** {@inheritDoc} */
@Override
public void forEach(final Consumer consumer) {
if (containsNullKey)
consumer.accept(value[n]);
for (int pos = n; pos-- != 0;)
if (!((key[pos]) == (null)))
consumer.accept(value[pos]);
}
};
return values;
}
/**
* Rehashes the map, making the table as small as possible.
*
*
* This method rehashes the table to the smallest size satisfying the load
* factor. It can be used when the set will not be changed anymore, so to
* optimize access speed and size.
*
*
* If the table size is already the minimum possible, this method does nothing.
*
* @return true if there was enough memory to trim the map.
* @see #trim(int)
*/
public boolean trim() {
final int l = arraySize(size, f);
if (l >= n || size > maxFill(l, f))
return true;
try {
rehash(l);
} catch (OutOfMemoryError cantDoIt) {
return false;
}
return true;
}
/**
* Rehashes this map if the table is too large.
*
*
* Let N be the smallest table size that can hold
* max(n,{@link #size()}) entries, still satisfying the load
* factor. If the current table size is smaller than or equal to N,
* this method does nothing. Otherwise, it rehashes this map in a table of size
* N.
*
*
* This method is useful when reusing maps. {@linkplain #clear() Clearing a map}
* leaves the table size untouched. If you are reusing a map many times, you can
* call this method with a typical size to avoid keeping around a very large
* table just because of a few large transient maps.
*
* @param n
* the threshold for the trimming.
* @return true if there was enough memory to trim the map.
* @see #trim()
*/
public boolean trim(final int n) {
final int l = HashCommon.nextPowerOfTwo((int) Math.ceil(n / f));
if (l >= n || size > maxFill(l, f))
return true;
try {
rehash(l);
} catch (OutOfMemoryError cantDoIt) {
return false;
}
return true;
}
/**
* Rehashes the map.
*
*
* This method implements the basic rehashing strategy, and may be overridden by
* subclasses implementing different rehashing strategies (e.g., disk-based
* rehashing). However, you should not override this method unless you
* understand the internal workings of this class.
*
* @param newN
* the new size
*/
@SuppressWarnings("unchecked")
protected void rehash(final int newN) {
final K key[] = this.key;
final V value[] = this.value;
final int mask = newN - 1; // Note that this is used by the hashing macro
final K newKey[] = (K[]) new Object[newN + 1];
final V newValue[] = (V[]) new Object[newN + 1];
int i = n, pos;
for (int j = realSize(); j-- != 0;) {
while (((key[--i]) == (null)));
if (!((newKey[pos = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(key[i])))
& mask]) == (null)))
while (!((newKey[pos = (pos + 1) & mask]) == (null)));
newKey[pos] = key[i];
newValue[pos] = value[i];
}
newValue[newN] = value[n];
n = newN;
this.mask = mask;
maxFill = maxFill(n, f);
this.key = newKey;
this.value = newValue;
}
/**
* Returns a deep copy of this map.
*
*
* This method performs a deep copy of this hash map; the data stored in the
* map, however, is not cloned. Note that this makes a difference only for
* object keys.
*
* @return a deep copy of this map.
*/
@Override
@SuppressWarnings("unchecked")
public Reference2ObjectOpenHashMap clone() {
Reference2ObjectOpenHashMap c;
try {
c = (Reference2ObjectOpenHashMap) super.clone();
} catch (CloneNotSupportedException cantHappen) {
throw new InternalError();
}
c.keys = null;
c.values = null;
c.entries = null;
c.containsNullKey = containsNullKey;
c.key = key.clone();
c.value = value.clone();
return c;
}
/**
* Returns a hash code for this map.
*
* This method overrides the generic method provided by the superclass. Since
* {@code equals()} is not overriden, it is important that the value returned by
* this method is the same value as the one returned by the overriden method.
*
* @return a hash code for this map.
*/
@Override
public int hashCode() {
int h = 0;
for (int j = realSize(), i = 0, t = 0; j-- != 0;) {
while (((key[i]) == (null)))
i++;
if (this != key[i])
t = (System.identityHashCode(key[i]));
if (this != value[i])
t ^= ((value[i]) == null ? 0 : (value[i]).hashCode());
h += t;
i++;
}
// Zero / null keys have hash zero.
if (containsNullKey)
h += ((value[n]) == null ? 0 : (value[n]).hashCode());
return h;
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
final K key[] = this.key;
final V value[] = this.value;
final MapIterator i = new MapIterator();
s.defaultWriteObject();
for (int j = size, e; j-- != 0;) {
e = i.nextEntry();
s.writeObject(key[e]);
s.writeObject(value[e]);
}
}
@SuppressWarnings("unchecked")
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
n = arraySize(size, f);
maxFill = maxFill(n, f);
mask = n - 1;
final K key[] = this.key = (K[]) new Object[n + 1];
final V value[] = this.value = (V[]) new Object[n + 1];
K k;
V v;
for (int i = size, pos; i-- != 0;) {
k = (K) s.readObject();
v = (V) s.readObject();
if (((k) == (null))) {
pos = n;
containsNullKey = true;
} else {
pos = (it.unimi.dsi.fastutil.HashCommon.mix(System.identityHashCode(k))) & mask;
while (!((key[pos]) == (null)))
pos = (pos + 1) & mask;
}
key[pos] = k;
value[pos] = v;
}
if (ASSERTS)
checkTable();
}
private void checkTable() {
}
}