com.carrotsearch.hppc.IntObjectHashMap Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of hppc Show documentation
Show all versions of hppc Show documentation
High Performance Primitive Collections: data structures (maps, sets, lists, stacks, queues) generated for combinations of object and primitive types to conserve JVM memory and speed up execution.
package com.carrotsearch.hppc;
import java.util.*;
import com.carrotsearch.hppc.cursors.*;
import com.carrotsearch.hppc.predicates.*;
import com.carrotsearch.hppc.procedures.*;
import static com.carrotsearch.hppc.HashContainers.*;
import static com.carrotsearch.hppc.Containers.*;
/**
* A hash map of int to Object, implemented using open
* addressing with linear probing for collision resolution.
*
* Note: read about important differences
* between hash and scatter sets.
*
* @see IntObjectScatterMap
* @see HPPC interfaces diagram
*/
@SuppressWarnings("unchecked")
@com.carrotsearch.hppc.Generated(
date = "2018-05-21T12:24:06+0200",
value = "KTypeVTypeHashMap.java")
public class IntObjectHashMap
implements
IntObjectMap,
Preallocable,
Cloneable
{
/**
* The array holding keys.
*/
public int []
keys;
/**
* The array holding values.
*/
public
Object []
values;
/**
* We perturb hash values with a container-unique
* seed to avoid problems with nearly-sorted-by-hash
* values on iterations.
*
* @see #hashKey
* @see "http://issues.carrot2.org/browse/HPPC-80"
* @see "http://issues.carrot2.org/browse/HPPC-103"
*/
protected int keyMixer;
/**
* The number of stored keys (assigned key slots), excluding the special
* "empty" key, if any (use {@link #size()} instead).
*
* @see #size()
*/
protected int assigned;
/**
* Mask for slot scans in {@link #keys}.
*/
protected int mask;
/**
* Expand (rehash) {@link #keys} when {@link #assigned} hits this value.
*/
protected int resizeAt;
/**
* Special treatment for the "empty slot" key marker.
*/
protected boolean hasEmptyKey;
/**
* The load factor for {@link #keys}.
*/
protected double loadFactor;
/**
* Per-instance hash order mixing strategy.
* @see #keyMixer
*/
protected HashOrderMixingStrategy orderMixer;
/**
* New instance with sane defaults.
*/
public IntObjectHashMap() {
this(DEFAULT_EXPECTED_ELEMENTS);
}
/**
* New instance with sane defaults.
*
* @param expectedElements
* The expected number of elements guaranteed not to cause buffer
* expansion (inclusive).
*/
public IntObjectHashMap(int expectedElements) {
this(expectedElements, DEFAULT_LOAD_FACTOR);
}
/**
* New instance with sane defaults.
*
* @param expectedElements
* The expected number of elements guaranteed not to cause buffer
* expansion (inclusive).
* @param loadFactor
* The load factor for internal buffers. Insane load factors (zero, full capacity)
* are rejected by {@link #verifyLoadFactor(double)}.
*/
public IntObjectHashMap(int expectedElements, double loadFactor) {
this(expectedElements, loadFactor, HashOrderMixing.defaultStrategy());
}
/**
* New instance with the provided defaults.
*
* @param expectedElements
* The expected number of elements guaranteed not to cause a rehash (inclusive).
* @param loadFactor
* The load factor for internal buffers. Insane load factors (zero, full capacity)
* are rejected by {@link #verifyLoadFactor(double)}.
* @param orderMixer
* Hash key order mixing strategy. See {@link HashOrderMixing} for predefined
* implementations. Use constant mixers only if you understand the potential
* consequences.
*/
public IntObjectHashMap(int expectedElements, double loadFactor, HashOrderMixingStrategy orderMixer) {
this.orderMixer = orderMixer;
this.loadFactor = verifyLoadFactor(loadFactor);
ensureCapacity(expectedElements);
}
/**
* Create a hash map from all key-value pairs of another container.
*/
public IntObjectHashMap(IntObjectAssociativeContainer container) {
this(container.size());
putAll(container);
}
/**
* {@inheritDoc}
*/
@Override
public VType put(int key, VType value) {
assert assigned < mask + 1;
final int mask = this.mask;
if (((key) == 0)) {
hasEmptyKey = true;
VType previousValue = (VType) values[mask + 1];
values[mask + 1] = value;
return previousValue;
} else {
final int[] keys = this.keys;
int slot = hashKey(key) & mask;
int existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
final VType previousValue = (VType) values[slot];
values[slot] = value;
return previousValue;
}
slot = (slot + 1) & mask;
}
if (assigned == resizeAt) {
allocateThenInsertThenRehash(slot, key, value);
} else {
keys[slot] = key;
values[slot] = value;
}
assigned++;
return null;
}
}
/**
* {@inheritDoc}
*/
@Override
public int putAll(IntObjectAssociativeContainer container) {
final int count = size();
for (IntObjectCursor c : container) {
put(c.key, c.value);
}
return size() - count;
}
/**
* Puts all key/value pairs from a given iterable into this map.
*/
@Override
public int putAll(Iterable> iterable){
final int count = size();
for (IntObjectCursor c : iterable) {
put(c.key, c.value);
}
return size() - count;
}
/**
* Trove-inspired API method. An equivalent
* of the following code:
*
* if (!map.containsKey(key)) map.put(value);
*
*
* @param key The key of the value to check.
* @param value The value to put if key does not exist.
* @return true if key did not exist and value
* was placed in the map.
*/
public boolean putIfAbsent(int key, VType value) {
int keyIndex = indexOf(key);
if (!indexExists(keyIndex)) {
indexInsert(keyIndex, key, value);
return true;
} else {
return false;
}
}
/**
* {@inheritDoc}
*/
@Override
public VType remove(int key) {
final int mask = this.mask;
if (((key) == 0)) {
hasEmptyKey = false;
VType previousValue = (VType) values[mask + 1];
values[mask + 1] = null;
return previousValue;
} else {
final int[] keys = this.keys;
int slot = hashKey(key) & mask;
int existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
final VType previousValue = (VType) values[slot];
shiftConflictingKeys(slot);
return previousValue;
}
slot = (slot + 1) & mask;
}
return null;
}
}
/**
* {@inheritDoc}
*/
@Override
public int removeAll(IntContainer other) {
final int before = size();
// Try to iterate over the smaller set of values or
// over the container that isn't implementing
// efficient contains() lookup.
if (other.size() >= size() &&
other instanceof IntLookupContainer) {
if (hasEmptyKey) {
if (other.contains(0)) {
hasEmptyKey = false;
values[mask + 1] = null;
}
}
final int[] keys = this.keys;
for (int slot = 0, max = this.mask; slot <= max;) {
int existing;
if (!((existing = keys[slot]) == 0) && other.contains(existing)) {
// Shift, do not increment slot.
shiftConflictingKeys(slot);
} else {
slot++;
}
}
} else {
for (IntCursor c : other) {
this.remove( c.value);
}
}
return before - size();
}
/**
* {@inheritDoc}
*/
@Override
public int removeAll(IntObjectPredicate predicate) {
final int before = size();
final int mask = this.mask;
if (hasEmptyKey) {
if (predicate.apply(0, (VType) values[mask + 1])) {
hasEmptyKey = false;
values[mask + 1] = null;
}
}
final int[] keys = this.keys;
final VType[] values = (VType[]) this.values;
for (int slot = 0; slot <= mask;) {
int existing;
if (!((existing = keys[slot]) == 0) &&
predicate.apply(existing, values[slot])) {
// Shift, do not increment slot.
shiftConflictingKeys(slot);
} else {
slot++;
}
}
return before - size();
}
/**
* {@inheritDoc}
*/
@Override
public int removeAll(IntPredicate predicate) {
final int before = size();
if (hasEmptyKey) {
if (predicate.apply(0)) {
hasEmptyKey = false;
values[mask + 1] = null;
}
}
final int[] keys = this.keys;
for (int slot = 0, max = this.mask; slot <= max;) {
int existing;
if (!((existing = keys[slot]) == 0) &&
predicate.apply(existing)) {
// Shift, do not increment slot.
shiftConflictingKeys(slot);
} else {
slot++;
}
}
return before - size();
}
/**
* {@inheritDoc}
*/
@Override
public VType get(int key) {
if (((key) == 0)) {
return hasEmptyKey ? (VType) values[mask + 1] : null;
} else {
final int[] keys = this.keys;
final int mask = this.mask;
int slot = hashKey(key) & mask;
int existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
return (VType) values[slot];
}
slot = (slot + 1) & mask;
}
return null;
}
}
/**
* {@inheritDoc}
*/
@Override
public VType getOrDefault(int key, VType defaultValue) {
if (((key) == 0)) {
return hasEmptyKey ? (VType) values[mask + 1] : defaultValue;
} else {
final int[] keys = this.keys;
final int mask = this.mask;
int slot = hashKey(key) & mask;
int existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
return (VType) values[slot];
}
slot = (slot + 1) & mask;
}
return defaultValue;
}
}
/**
* {@inheritDoc}
*/
@Override
public boolean containsKey(int key) {
if (((key) == 0)) {
return hasEmptyKey;
} else {
final int[] keys = this.keys;
final int mask = this.mask;
int slot = hashKey(key) & mask;
int existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
return true;
}
slot = (slot + 1) & mask;
}
return false;
}
}
/**
* {@inheritDoc}
*/
@Override
public int indexOf(int key) {
final int mask = this.mask;
if (((key) == 0)) {
return hasEmptyKey ? mask + 1 : ~(mask + 1);
} else {
final int[] keys = this.keys;
int slot = hashKey(key) & mask;
int existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
return slot;
}
slot = (slot + 1) & mask;
}
return ~slot;
}
}
/**
* {@inheritDoc}
*/
@Override
public boolean indexExists(int index) {
assert index < 0 ||
(index >= 0 && index <= mask) ||
(index == mask + 1 && hasEmptyKey);
return index >= 0;
}
/**
* {@inheritDoc}
*/
@Override
public VType indexGet(int index) {
assert index >= 0 : "The index must point at an existing key.";
assert index <= mask ||
(index == mask + 1 && hasEmptyKey);
return (VType) values[index];
}
/**
* {@inheritDoc}
*/
@Override
public VType indexReplace(int index, VType newValue) {
assert index >= 0 : "The index must point at an existing key.";
assert index <= mask ||
(index == mask + 1 && hasEmptyKey);
VType previousValue = (VType) values[index];
values[index] = newValue;
return previousValue;
}
/**
* {@inheritDoc}
*/
@Override
public void indexInsert(int index, int key, VType value) {
assert index < 0 : "The index must not point at an existing key.";
index = ~index;
if (((key) == 0)) {
assert index == mask + 1;
values[index] = value;
hasEmptyKey = true;
} else {
assert ((keys[index]) == 0);
if (assigned == resizeAt) {
allocateThenInsertThenRehash(index, key, value);
} else {
keys[index] = key;
values[index] = value;
}
assigned++;
}
}
/**
* {@inheritDoc}
*/
@Override
public void clear() {
assigned = 0;
hasEmptyKey = false;
Arrays.fill(keys, 0);
/* */
Arrays.fill(values, null);
/* */
}
/**
* {@inheritDoc}
*/
@Override
public void release() {
assigned = 0;
hasEmptyKey = false;
keys = null;
values = null;
ensureCapacity(Containers.DEFAULT_EXPECTED_ELEMENTS);
}
/**
* {@inheritDoc}
*/
@Override
public int size() {
return assigned + (hasEmptyKey ? 1 : 0);
}
/**
* {@inheritDoc}
*/
public boolean isEmpty() {
return size() == 0;
}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
int h = hasEmptyKey ? 0xDEADBEEF : 0;
for (IntObjectCursor c : this) {
h += BitMixer.mix(c.key) +
BitMixer.mix(c.value);
}
return h;
}
/**
* {@inheritDoc}
*/
@Override
public boolean equals(Object obj) {
return obj != null &&
getClass() == obj.getClass() &&
equalElements(getClass().cast(obj));
}
/**
* Return true if all keys of some other container exist in this container.
* Values are compared using {@link Objects#equals(Object)} method.
*/
protected boolean equalElements(IntObjectHashMap other) {
if (other.size() != size()) {
return false;
}
for (IntObjectCursor c : other) {
int key = c.key;
if (!containsKey(key) ||
!java.util.Objects.equals(get(key), c.value)) {
return false;
}
}
return true;
}
/**
* Ensure this container can hold at least the
* given number of keys (entries) without resizing its buffers.
*
* @param expectedElements The total number of keys, inclusive.
*/
@Override
public void ensureCapacity(int expectedElements) {
if (expectedElements > resizeAt || keys == null) {
final int[] prevKeys = this.keys;
final VType[] prevValues = (VType[]) this.values;
allocateBuffers(minBufferSize(expectedElements, loadFactor));
if (prevKeys != null && !isEmpty()) {
rehash(prevKeys, prevValues);
}
}
}
/**
* An iterator implementation for {@link #iterator}.
*/
private final class EntryIterator extends AbstractIterator> {
private final IntObjectCursor cursor;
private final int max = mask + 1;
private int slot = -1;
public EntryIterator() {
cursor = new IntObjectCursor();
}
@Override
protected IntObjectCursor fetch() {
if (slot < max) {
int existing;
for (slot++; slot < max; slot++) {
if (!((existing = keys[slot]) == 0)) {
cursor.index = slot;
cursor.key = existing;
cursor.value = (VType) values[slot];
return cursor;
}
}
}
if (slot == max && hasEmptyKey) {
cursor.index = slot;
cursor.key = 0;
cursor.value = (VType) values[max];
slot++;
return cursor;
}
return done();
}
}
/**
* {@inheritDoc}
*/
@Override
public Iterator> iterator() {
return new EntryIterator();
}
/**
* {@inheritDoc}
*/
@Override
public > T forEach(T procedure) {
final int[] keys = this.keys;
final VType[] values = (VType[]) this.values;
if (hasEmptyKey) {
procedure.apply(0, (VType) values[mask + 1]);
}
for (int slot = 0, max = this.mask; slot <= max; slot++) {
if (!((keys[slot]) == 0)) {
procedure.apply(keys[slot], values[slot]);
}
}
return procedure;
}
/**
* {@inheritDoc}
*/
@Override
public > T forEach(T predicate) {
final int[] keys = this.keys;
final VType[] values = (VType[]) this.values;
if (hasEmptyKey) {
if (!predicate.apply(0, (VType) values[mask + 1])) {
return predicate;
}
}
for (int slot = 0, max = this.mask; slot <= max; slot++) {
if (!((keys[slot]) == 0)) {
if (!predicate.apply(keys[slot], values[slot])) {
break;
}
}
}
return predicate;
}
/**
* Returns a specialized view of the keys of this associated container. The
* view additionally implements {@link ObjectLookupContainer}.
*/
public KeysContainer keys() {
return new KeysContainer();
}
/**
* A view of the keys inside this hash map.
*/
public final class KeysContainer extends AbstractIntCollection
implements IntLookupContainer {
private final IntObjectHashMap owner = IntObjectHashMap.this;
@Override
public boolean contains(int e) {
return owner.containsKey(e);
}
@Override
public T forEach(final T procedure) {
owner.forEach(new IntObjectProcedure() {
@Override
public void apply(int key, VType value) {
procedure.apply(key);
}
});
return procedure;
}
@Override
public T forEach(final T predicate) {
owner.forEach(new IntObjectPredicate() {
@Override
public boolean apply(int key, VType value) {
return predicate.apply(key);
}
});
return predicate;
}
@Override
public boolean isEmpty() {
return owner.isEmpty();
}
@Override
public Iterator iterator() {
return new KeysIterator();
}
@Override
public int size() {
return owner.size();
}
@Override
public void clear() {
owner.clear();
}
@Override
public void release() {
owner.release();
}
@Override
public int removeAll(IntPredicate predicate) {
return owner.removeAll(predicate);
}
@Override
public int removeAll(final int e) {
final boolean hasKey = owner.containsKey(e);
if (hasKey) {
owner.remove(e);
return 1;
} else {
return 0;
}
}
};
/**
* An iterator over the set of assigned keys.
*/
private final class KeysIterator extends AbstractIterator {
private final IntCursor cursor;
private final int max = mask + 1;
private int slot = -1;
public KeysIterator() {
cursor = new IntCursor();
}
@Override
protected IntCursor fetch() {
if (slot < max) {
int existing;
for (slot++; slot < max; slot++) {
if (!((existing = keys[slot]) == 0)) {
cursor.index = slot;
cursor.value = existing;
return cursor;
}
}
}
if (slot == max && hasEmptyKey) {
cursor.index = slot;
cursor.value = 0;
slot++;
return cursor;
}
return done();
}
}
/**
* @return Returns a container with all values stored in this map.
*/
@Override
public ObjectCollection values() {
return new ValuesContainer();
}
/**
* A view over the set of values of this map.
*/
private final class ValuesContainer extends AbstractObjectCollection {
private final IntObjectHashMap owner = IntObjectHashMap.this;
@Override
public int size() {
return owner.size();
}
@Override
public boolean isEmpty() {
return owner.isEmpty();
}
@Override
public boolean contains(VType value) {
for (IntObjectCursor c : owner) {
if (java.util.Objects.equals(c.value, value)) {
return true;
}
}
return false;
}
@Override
public > T forEach(T procedure) {
for (IntObjectCursor c : owner) {
procedure.apply(c.value);
}
return procedure;
}
@Override
public > T forEach(T predicate) {
for (IntObjectCursor c : owner) {
if (!predicate.apply(c.value)) {
break;
}
}
return predicate;
}
@Override
public Iterator> iterator() {
return new ValuesIterator();
}
@Override
public int removeAll(final VType e) {
return owner.removeAll(new IntObjectPredicate() {
@Override
public boolean apply(int key, VType value) {
return java.util.Objects.equals(value, e);
}
});
}
@Override
public int removeAll(final ObjectPredicate predicate) {
return owner.removeAll(new IntObjectPredicate() {
@Override
public boolean apply(int key, VType value) {
return predicate.apply(value);
}
});
}
@Override
public void clear() {
owner.clear();
}
@Override
public void release() {
owner.release();
}
}
/**
* An iterator over the set of assigned values.
*/
private final class ValuesIterator extends AbstractIterator> {
private final ObjectCursor cursor;
private final int max = mask + 1;
private int slot = -1;
public ValuesIterator() {
cursor = new ObjectCursor();
}
@Override
protected ObjectCursor fetch() {
if (slot < max) {
for (slot++; slot < max; slot++) {
if (!(( keys[slot]) == 0)) {
cursor.index = slot;
cursor.value = (VType) values[slot];
return cursor;
}
}
}
if (slot == max && hasEmptyKey) {
cursor.index = slot;
cursor.value = (VType) values[max];
slot++;
return cursor;
}
return done();
}
}
/**
* {@inheritDoc}
*/
@Override
public IntObjectHashMap clone() {
try {
/* */
IntObjectHashMap cloned = (IntObjectHashMap) super.clone();
cloned.keys = keys.clone();
cloned.values = values.clone();
cloned.hasEmptyKey = cloned.hasEmptyKey;
cloned.orderMixer = orderMixer.clone();
return cloned;
} catch (CloneNotSupportedException e) {
throw new RuntimeException(e);
}
}
/**
* Convert the contents of this map to a human-friendly string.
*/
@Override
public String toString() {
final StringBuilder buffer = new StringBuilder();
buffer.append("[");
boolean first = true;
for (IntObjectCursor cursor : this) {
if (!first) {
buffer.append(", ");
}
buffer.append(cursor.key);
buffer.append("=>");
buffer.append(cursor.value);
first = false;
}
buffer.append("]");
return buffer.toString();
}
@Override
public String visualizeKeyDistribution(int characters) {
return IntBufferVisualizer.visualizeKeyDistribution(keys, mask, characters);
}
/**
* Creates a hash map from two index-aligned arrays of key-value pairs.
*/
public static IntObjectHashMap from(int[] keys, VType[] values) {
if (keys.length != values.length) {
throw new IllegalArgumentException("Arrays of keys and values must have an identical length.");
}
IntObjectHashMap map = new IntObjectHashMap<>(keys.length);
for (int i = 0; i < keys.length; i++) {
map.put(keys[i], values[i]);
}
return map;
}
/**
* Returns a hash code for the given key.
*
* The default implementation mixes the hash of the key with {@link #keyMixer}
* to differentiate hash order of keys between hash containers. Helps
* alleviate problems resulting from linear conflict resolution in open
* addressing.
*
* The output from this function should evenly distribute keys across the
* entire integer range.
*/
protected
int hashKey(int key) {
assert !((key) == 0); // Handled as a special case (empty slot marker).
return BitMixer.mix(key, this.keyMixer);
}
/**
* Validate load factor range and return it. Override and suppress if you need
* insane load factors.
*/
protected double verifyLoadFactor(double loadFactor) {
checkLoadFactor(loadFactor, MIN_LOAD_FACTOR, MAX_LOAD_FACTOR);
return loadFactor;
}
/**
* Rehash from old buffers to new buffers.
*/
protected void rehash(int[] fromKeys, VType[] fromValues) {
assert fromKeys.length == fromValues.length &&
HashContainers.checkPowerOfTwo(fromKeys.length - 1);
// Rehash all stored key/value pairs into the new buffers.
final int[] keys = this.keys;
final VType[] values = (VType[]) this.values;
final int mask = this.mask;
int existing;
// Copy the zero element's slot, then rehash everything else.
int from = fromKeys.length - 1;
keys[keys.length - 1] = fromKeys[from];
values[values.length - 1] = fromValues[from];
while (--from >= 0) {
if (!((existing = fromKeys[from]) == 0)) {
int slot = hashKey(existing) & mask;
while (!((keys[slot]) == 0)) {
slot = (slot + 1) & mask;
}
keys[slot] = existing;
values[slot] = fromValues[from];
}
}
}
/**
* Allocate new internal buffers. This method attempts to allocate
* and assign internal buffers atomically (either allocations succeed or not).
*/
protected void allocateBuffers(int arraySize) {
assert Integer.bitCount(arraySize) == 1;
// Compute new hash mixer candidate before expanding.
final int newKeyMixer = this.orderMixer.newKeyMixer(arraySize);
// Ensure no change is done if we hit an OOM.
int[] prevKeys = this.keys;
VType[] prevValues = (VType[]) this.values;
try {
int emptyElementSlot = 1;
this.keys = (new int [arraySize + emptyElementSlot]);
this.values = ((VType[]) new Object [arraySize + emptyElementSlot]);
} catch (OutOfMemoryError e) {
this.keys = prevKeys;
this.values = prevValues;
throw new BufferAllocationException(
"Not enough memory to allocate buffers for rehashing: %,d -> %,d",
e,
this.mask + 1,
arraySize);
}
this.resizeAt = expandAtCount(arraySize, loadFactor);
this.keyMixer = newKeyMixer;
this.mask = arraySize - 1;
}
/**
* This method is invoked when there is a new key/ value pair to be inserted into
* the buffers but there is not enough empty slots to do so.
*
* New buffers are allocated. If this succeeds, we know we can proceed
* with rehashing so we assign the pending element to the previous buffer
* (possibly violating the invariant of having at least one empty slot)
* and rehash all keys, substituting new buffers at the end.
*/
protected void allocateThenInsertThenRehash(int slot, int pendingKey, VType pendingValue) {
assert assigned == resizeAt
&& (( keys[slot]) == 0)
&& !((pendingKey) == 0);
// Try to allocate new buffers first. If we OOM, we leave in a consistent state.
final int[] prevKeys = this.keys;
final VType[] prevValues = (VType[]) this.values;
allocateBuffers(nextBufferSize(mask + 1, size(), loadFactor));
assert this.keys.length > prevKeys.length;
// We have succeeded at allocating new data so insert the pending key/value at
// the free slot in the old arrays before rehashing.
prevKeys[slot] = pendingKey;
prevValues[slot] = pendingValue;
// Rehash old keys, including the pending key.
rehash(prevKeys, prevValues);
}
/**
* Shift all the slot-conflicting keys and values allocated to
* (and including) slot.
*/
protected void shiftConflictingKeys(int gapSlot) {
final int[] keys = this.keys;
final VType[] values = (VType[]) this.values;
final int mask = this.mask;
// Perform shifts of conflicting keys to fill in the gap.
int distance = 0;
while (true) {
final int slot = (gapSlot + (++distance)) & mask;
final int existing = keys[slot];
if (((existing) == 0)) {
break;
}
final int idealSlot = hashKey(existing);
final int shift = (slot - idealSlot) & mask;
if (shift >= distance) {
// Entry at this position was originally at or before the gap slot.
// Move the conflict-shifted entry to the gap's position and repeat the procedure
// for any entries to the right of the current position, treating it
// as the new gap.
keys[gapSlot] = existing;
values[gapSlot] = values[slot];
gapSlot = slot;
distance = 0;
}
}
// Mark the last found gap slot without a conflict as empty.
keys[gapSlot] = 0;
values[gapSlot] = null;
assigned--;
}
}