it.unimi.dsi.fastutil.objects.Object2FloatOpenCustomHashMap Maven / Gradle / Ivy
Show all versions of fastutil Show documentation
/*
* 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 it.unimi.dsi.fastutil.floats.FloatCollection;
import it.unimi.dsi.fastutil.floats.AbstractFloatCollection;
import it.unimi.dsi.fastutil.floats.FloatIterator;
import it.unimi.dsi.fastutil.objects.AbstractObjectSet;
/** A type-specific hash map with a fast, small-footprint implementation whose {@linkplain it.unimi.dsi.fastutil.Hash.Strategy hashing strategy}
* is specified at creation time.
*
* 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, 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 Object2FloatOpenCustomHashMap extends AbstractObject2FloatMap 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 float[] value;
/** The mask for wrapping a position counter. */
protected transient int mask;
/** Whether this set contains the key zero. */
protected transient boolean containsNullKey;
/** The hash strategy of this custom map. */
protected Strategy strategy;
/** 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;
/** 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 ObjectSet keys;
/** Cached collection of values. */
protected transient FloatCollection values;
/** Creates a new hash map.
*
* The actual table size will be the least power of two greater than expected/f.
*
* @param expected the expected number of elements in the hash set.
* @param f the load factor.
* @param strategy the strategy.
*/
@SuppressWarnings("unchecked")
public Object2FloatOpenCustomHashMap(final int expected, final float f, final Strategy strategy) {
this.strategy = strategy;
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;
n = arraySize(expected, f);
mask = n - 1;
maxFill = maxFill(n, f);
key = (K[]) new Object[n + 1];
value = new float[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.
* @param strategy the strategy.
*/
public Object2FloatOpenCustomHashMap(final int expected, final Strategy strategy) {
this(expected, DEFAULT_LOAD_FACTOR, strategy);
}
/** Creates a new hash map with initial expected {@link Hash#DEFAULT_INITIAL_SIZE} entries
* and {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
* @param strategy the strategy.
*/
public Object2FloatOpenCustomHashMap(final Strategy strategy) {
this(DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, strategy);
}
/** 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.
* @param strategy the strategy.
*/
public Object2FloatOpenCustomHashMap(final Map m, final float f, final Strategy strategy) {
this(m.size(), f, strategy);
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.
* @param strategy the strategy.
*/
public Object2FloatOpenCustomHashMap(final Map m, final Strategy strategy) {
this(m, DEFAULT_LOAD_FACTOR, strategy);
}
/** 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.
* @param strategy the strategy.
*/
public Object2FloatOpenCustomHashMap(final Object2FloatMap m, final float f, final Strategy strategy) {
this(m.size(), f, strategy);
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.
* @param strategy the strategy.
*/
public Object2FloatOpenCustomHashMap(final Object2FloatMap m, final Strategy strategy) {
this(m, DEFAULT_LOAD_FACTOR, strategy);
}
/** 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.
* @param strategy the strategy.
* @throws IllegalArgumentException if k and v have different lengths.
*/
public Object2FloatOpenCustomHashMap(final K[] k, final float[] v, final float f, final Strategy strategy) {
this(k.length, f, strategy);
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.
* @param strategy the strategy.
* @throws IllegalArgumentException if k and v have different lengths.
*/
public Object2FloatOpenCustomHashMap(final K[] k, final float[] v, final Strategy strategy) {
this(k, v, DEFAULT_LOAD_FACTOR, strategy);
}
/** Returns the hashing strategy.
*
* @return the hashing strategy of this custom hash map.
*/
public Strategy strategy() {
return strategy;
}
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 float removeEntry(final int pos) {
final float oldValue = value[pos];
size--;
shiftKeys(pos);
if (size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE) rehash(n / 2);
return oldValue;
}
private float removeNullEntry() {
containsNullKey = false;
key[n] = null;
final float oldValue = value[n];
size--;
if (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);
}
private int insert(final K k, final float v) {
int pos;
if (( strategy.equals( (k), (null) ) )) {
if (containsNullKey) return n;
containsNullKey = true;
pos = n;
}
else {
K curr;
final K[] key = this.key;
// The starting point.
if (! ( (curr = key[pos = ( it.unimi.dsi.fastutil.HashCommon.mix( strategy.hashCode(k) ) ) & mask]) == null )) {
if (( strategy.equals( (curr), (k) ) )) return pos;
while(! ( (curr = key[pos = (pos + 1) & mask]) == null ))
if (( strategy.equals( (curr), (k) ) )) return pos;
}
}
key[pos] = k;
value[pos] = v;
if (size++ >= maxFill) rehash(arraySize(size + 1, f));
if (ASSERTS) checkTable();
return -1;
}
@Override
public float put(final K k, final float v) {
final int pos = insert(k, v);
if (pos < 0) return defRetValue;
final float oldValue = value[pos];
value[pos] = v;
return oldValue;
}
private float addToValue(final int pos, final float incr) {
final float oldValue = value[pos];
value[pos] = oldValue + incr;
return oldValue;
}
/** Adds an increment to value currently associated with a key.
*
* Note that this method respects the {@linkplain #defaultReturnValue() default return value} semantics: when
* called with a key that does not currently appears in the map, the key
* will be associated with the default return value plus
* the given increment.
*
* @param k the key.
* @param incr the increment.
* @return the old value, or the {@linkplain #defaultReturnValue() default return value} if no value was present for the given key.
*/
public float addTo(final K k, final float incr) {
int pos;
if (( strategy.equals( (k), (null) ) )) {
if (containsNullKey) return addToValue(n, incr);
pos = n;
containsNullKey = true;
}
else {
K curr;
final K[] key = this.key;
// The starting point.
if (! ( (curr = key[pos = ( it.unimi.dsi.fastutil.HashCommon.mix( strategy.hashCode(k) ) ) & mask]) == null )) {
if (( strategy.equals( (curr), (k) ) )) return addToValue(pos, incr);
while(! ( (curr = key[pos = (pos + 1) & mask]) == null ))
if (( strategy.equals( (curr), (k) ) )) return addToValue(pos, incr);
}
}
key[pos] = k;
value[pos] = defRetValue + incr;
if (size++ >= maxFill) rehash(arraySize(size + 1, f));
if (ASSERTS) checkTable();
return defRetValue;
}
/** 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);
return;
}
slot = ( it.unimi.dsi.fastutil.HashCommon.mix( strategy.hashCode(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];
}
}
@SuppressWarnings("unchecked")
public float removeFloat(final Object k) {
if (( strategy.equals( ((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( strategy.hashCode( (K) k) ) ) & mask]) == null )) return defRetValue;
if (( strategy.equals( (K) (k), (curr) ) )) return removeEntry(pos);
while(true) {
if (( (curr = key[pos = (pos + 1) & mask]) == null )) return defRetValue;
if (( strategy.equals( (K) (k), (curr) ) )) return removeEntry(pos);
}
}
@Override
@SuppressWarnings("unchecked")
public float getFloat(final Object k) {
if (( strategy.equals( ((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( strategy.hashCode( (K) k) ) ) & mask]) == null )) return defRetValue;
if (( strategy.equals( (K) (k), (curr) ) )) return value[pos];
// There's always an unused entry.
while(true) {
if (( (curr = key[pos = (pos + 1) & mask]) == null )) return defRetValue;
if (( strategy.equals( (K) (k), (curr) ) )) return value[pos];
}
}
@Override
@SuppressWarnings("unchecked")
public boolean containsKey(final Object k) {
if (( strategy.equals( ((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( strategy.hashCode( (K) k) ) ) & mask]) == null )) return false;
if (( strategy.equals( (K) (k), (curr) ) )) return true;
// There's always an unused entry.
while(true) {
if (( (curr = key[pos = (pos + 1) & mask]) == null )) return false;
if (( strategy.equals( (K) (k), (curr) ) )) return true;
}
}
@Override
public boolean containsValue(final float v) {
final float value[] = this.value;
final K key[] = this.key;
if (containsNullKey && ( (value[n]) == (v) )) return true;
for(int i = n; i-- != 0;) if (! ( (key[i]) == null ) && ( (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));
}
@Override
public int size() {
return size;
}
@Override
public boolean isEmpty() {
return size == 0;
}
/** A no-op for backward compatibility.
*
* @param growthFactor unused.
* @deprecated Since fastutil 6.1.0, hash tables are doubled when they are too full.
*/
@Deprecated
public void growthFactor(int growthFactor) {}
/** Gets the growth factor (2).
*
* @return the growth factor of this set, which is fixed (2).
* @see #growthFactor(int)
* @deprecated Since fastutil 6.1.0, hash tables are doubled when they are too full.
*/
@Deprecated
public int growthFactor() {
return 16;
}
/** 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 Object2FloatMap.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 float getFloatValue() {
return value[index];
}
@Override
public float setValue(final float v) {
final float oldValue = value[index];
value[index] = v;
return oldValue;
}
/** {@inheritDoc}
* @deprecated Please use the corresponding type-specific method instead. */
@Deprecated
@Override
public Float getValue() {
return (Float.valueOf(value[index]));
}
/** {@inheritDoc}
* @deprecated Please use the corresponding type-specific method instead. */
@Deprecated
@Override
public Float setValue(final Float v) {
return (Float.valueOf(setValue(((v).floatValue()))));
}
@SuppressWarnings("unchecked")
@Override
public boolean equals(final Object o) {
if (!(o instanceof Map.Entry)) return false;
Map.Entry e = (Map.Entry)o;
return ( strategy.equals( (key[index]), ((e.getKey())) ) ) && ( (value[index]) == (((e.getValue()).floatValue())) );
}
@Override
public int hashCode() {
return ( strategy.hashCode(key[index]) ) ^ it.unimi.dsi.fastutil.HashCommon.float2int(value[index]);
}
@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 = Object2FloatOpenCustomHashMap.this.containsNullKey;
/** A lazily allocated list containing keys of entries that have wrapped around the table because of removals. */
ObjectArrayList 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[] = Object2FloatOpenCustomHashMap.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( strategy.hashCode(k) ) ) & mask;
while (! ( strategy.equals( (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 final void shiftKeys(int pos) {
// Shift entries with the same hash.
int last, slot;
K curr;
final K[] key = Object2FloatOpenCustomHashMap.this.key;
for(;;) {
pos = ((last = pos) + 1) & mask;
for(;;) {
if (( (curr = key[pos]) == null )) {
key[last] = (null);
return;
}
slot = ( it.unimi.dsi.fastutil.HashCommon.mix( strategy.hashCode(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 ObjectArrayList (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;
}
else if (pos >= 0) shiftKeys(last);
else {
// We're removing wrapped entries.
Object2FloatOpenCustomHashMap.this.removeFloat(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 {
public ObjectIterator > iterator() {
return new EntryIterator();
}
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;
if (e.getValue() == null || ! (e.getValue() instanceof Float)) return false;
final K k = ((K) e.getKey());
final float v = ((((Float)( e.getValue())).floatValue()));
if (( strategy.equals( (k), (null) ) )) return Object2FloatOpenCustomHashMap.this.containsNullKey && ( (value[n]) == (v) );
K curr;
final K[] key = Object2FloatOpenCustomHashMap.this.key;
int pos;
// The starting point.
if (( (curr = key[pos = ( it.unimi.dsi.fastutil.HashCommon.mix( strategy.hashCode(k) ) ) & mask]) == null )) return false;
if (( strategy.equals( (k), (curr) ) )) return ( (value[pos]) == (v) );
// There's always an unused entry.
while(true) {
if (( (curr = key[pos = (pos + 1) & mask]) == null )) return false;
if (( strategy.equals( (k), (curr) ) )) return ( (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;
if (e.getValue() == null || ! (e.getValue() instanceof Float)) return false;
final K k = ((K) e.getKey());
final float v = ((((Float)( e.getValue())).floatValue()));
if (( strategy.equals( (k), (null) ) )) {
if (containsNullKey && ( (value[n]) == (v) )) {
removeNullEntry();
return true;
}
return false;
}
K curr;
final K[] key = Object2FloatOpenCustomHashMap.this.key;
int pos;
// The starting point.
if (( (curr = key[pos = ( it.unimi.dsi.fastutil.HashCommon.mix( strategy.hashCode(k) ) ) & mask]) == null )) return false;
if (( strategy.equals( (curr), (k) ) )) {
if (( (value[pos]) == (v) )) {
removeEntry(pos);
return true;
}
return false;
}
while(true) {
if (( (curr = key[pos = (pos + 1) & mask]) == null )) return false;
if (( strategy.equals( (curr), (k) ) )) {
if (( (value[pos]) == (v) )) {
removeEntry(pos);
return true;
}
}
}
}
@Override
public int size() {
return size;
}
@Override
public void clear() {
Object2FloatOpenCustomHashMap.this.clear();
}
}
@Override
public FastEntrySet object2FloatEntrySet() {
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 AbstractObjectSet {
@Override
public ObjectIterator iterator() {
return new KeyIterator();
}
@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;
Object2FloatOpenCustomHashMap.this.removeFloat(k);
return size != oldSize;
}
@Override
public void clear() {
Object2FloatOpenCustomHashMap.this.clear();
}
}
@Override
public ObjectSet 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 FloatIterator {
public ValueIterator() { super(); }
@Override
public float nextFloat() { return value[nextEntry()]; }
@Deprecated
@Override
public Float next() { return (Float.valueOf(value[nextEntry()])); }
}
@Override
public FloatCollection values() {
if (values == null) values = new AbstractFloatCollection () {
@Override
public FloatIterator iterator() {
return new ValueIterator();
}
@Override
public int size() {
return size;
}
@Override
public boolean contains(float v) {
return containsValue(v);
}
@Override
public void clear() {
Object2FloatOpenCustomHashMap.this.clear();
}
};
return values;
}
/** A no-op for backward compatibility. The kind of tables implemented by
* this class never need rehashing.
*
*
If you need to reduce the table size to fit exactly
* this set, use {@link #trim()}.
*
* @return true.
* @see #trim()
* @deprecated A no-op.
*/
@Deprecated
public boolean rehash() {
return true;
}
/** 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
* overriden 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 float 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 float newValue[] = new float[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( strategy.hashCode(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 Object2FloatOpenCustomHashMap clone() {
Object2FloatOpenCustomHashMap c;
try {
c = (Object2FloatOpenCustomHashMap )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();
c.strategy = strategy;
return c;
}
/** Returns a hash code for this map.
*
* This method overrides the generic method provided by the superclass.
* Since 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 = ( strategy.hashCode(key[i]) );
t ^= it.unimi.dsi.fastutil.HashCommon.float2int(value[i]);
h += t;
i++;
}
// Zero / null keys have hash zero.
if (containsNullKey) h += it.unimi.dsi.fastutil.HashCommon.float2int(value[n]);
return h;
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
final K key[] = this.key;
final float 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.writeFloat(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 float value[] = this.value = new float[n + 1];
K k;
float v;
for(int i = size, pos; i-- != 0;) {
k = (K) s.readObject();
v = s.readFloat();
if (( strategy.equals( (k), (null) ) )) {
pos = n;
containsNullKey = true;
}
else {
pos = ( it.unimi.dsi.fastutil.HashCommon.mix( strategy.hashCode(k) ) ) & mask;
while (! ( (key[pos]) == null )) pos = (pos + 1) & mask;
}
key[pos] = k;
value[pos] = v;
}
if (ASSERTS) checkTable();
}
private void checkTable() {}
}