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 char
to char
, implemented using open
addressing with linear probing for collision resolution.
Note: read about important differences
between hash and scatter sets.
See Also:
/**
* A hash map of <code>char</code> to <code>char</code>, implemented using open
* addressing with linear probing for collision resolution.
*
* <p><strong>Note:</strong> read about <a href="{@docRoot}/overview-summary.html#scattervshash">important differences
* between hash and scatter sets</a>.</p>
*
* @see CharCharScatterMap
* @see <a href="{@docRoot}/overview-summary.html#interfaces">HPPC interfaces diagram</a>
*/
@com.carrotsearch.hppc.Generated(
date = "2018-05-21T12:24:05+0200",
value = "KTypeVTypeHashMap.java")
public class CharCharHashMap
implements
CharCharMap,
Preallocable,
Cloneable
{
The array holding keys.
/**
* The array holding keys.
*/
public char []
keys;
The array holding values.
/**
* The array holding values.
*/
public char []
values;
We perturb hash values with a container-unique
seed to avoid problems with nearly-sorted-by-hash
values on iterations.
See Also: - hashKey
- http://issues.carrot2.org/browse/HPPC-80
- http://issues.carrot2.org/browse/HPPC-103
/**
* 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 size()
instead). See Also:
/**
* 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 keys
. /**
* 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.
/**
* Special treatment for the "empty slot" key marker.
*/
protected boolean hasEmptyKey;
The load factor for keys
. /**
* The load factor for {@link #keys}.
*/
protected double loadFactor;
Per-instance hash order mixing strategy.
See Also: - keyMixer
/**
* Per-instance hash order mixing strategy.
* @see #keyMixer
*/
protected HashOrderMixingStrategy orderMixer;
New instance with sane defaults.
/**
* New instance with sane defaults.
*/
public CharCharHashMap() {
this(DEFAULT_EXPECTED_ELEMENTS);
}
New instance with sane defaults.
Params: - expectedElements –
The expected number of elements guaranteed not to cause buffer
expansion (inclusive).
/**
* New instance with sane defaults.
*
* @param expectedElements
* The expected number of elements guaranteed not to cause buffer
* expansion (inclusive).
*/
public CharCharHashMap(int expectedElements) {
this(expectedElements, DEFAULT_LOAD_FACTOR);
}
New instance with sane defaults.
Params: - expectedElements –
The expected number of elements guaranteed not to cause buffer
expansion (inclusive).
- loadFactor – The load factor for internal buffers. Insane load factors (zero, full capacity) are rejected by
verifyLoadFactor(double)
.
/**
* 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 CharCharHashMap(int expectedElements, double loadFactor) {
this(expectedElements, loadFactor, HashOrderMixing.defaultStrategy());
}
New instance with the provided defaults.
Params: - expectedElements –
The expected number of elements guaranteed not to cause a rehash (inclusive).
- loadFactor – The load factor for internal buffers. Insane load factors (zero, full capacity) are rejected by
verifyLoadFactor(double)
. - orderMixer – Hash key order mixing strategy. See
HashOrderMixing
for predefined implementations. Use constant mixers only if you understand the potential consequences.
/**
* 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 CharCharHashMap(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.
/**
* Create a hash map from all key-value pairs of another container.
*/
public CharCharHashMap(CharCharAssociativeContainer container) {
this(container.size());
putAll(container);
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public char put(char key, char value) {
assert assigned < mask + 1;
final int mask = this.mask;
if (((key) == 0)) {
hasEmptyKey = true;
char previousValue = values[mask + 1];
values[mask + 1] = value;
return previousValue;
} else {
final char[] keys = this.keys;
int slot = hashKey(key) & mask;
char existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
final char previousValue = 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 ((char) 0);
}
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public int putAll(CharCharAssociativeContainer container) {
final int count = size();
for (CharCharCursor c : container) {
put(c.key, c.value);
}
return size() - count;
}
Puts all key/value pairs from a given iterable into this map.
/**
* Puts all key/value pairs from a given iterable into this map.
*/
@Override
public int putAll(Iterable<? extends CharCharCursor> iterable){
final int count = size();
for (CharCharCursor 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);
Params: - key – The key of the value to check.
- value – The value to put if
key
does not exist.
Returns: true
if key
did not exist and value
was placed in the map.
/**
* <a href="http://trove4j.sourceforge.net">Trove</a>-inspired API method. An equivalent
* of the following code:
* <pre>
* if (!map.containsKey(key)) map.put(value);
* </pre>
*
* @param key The key of the value to check.
* @param value The value to put if <code>key</code> does not exist.
* @return <code>true</code> if <code>key</code> did not exist and <code>value</code>
* was placed in the map.
*/
public boolean putIfAbsent(char key, char value) {
int keyIndex = indexOf(key);
if (!indexExists(keyIndex)) {
indexInsert(keyIndex, key, value);
return true;
} else {
return false;
}
}
If key
exists, putValue
is inserted into the map,
otherwise any existing value is incremented by additionValue
.
Params: - key –
The key of the value to adjust.
- putValue –
The value to put if
key
does not exist. - incrementValue –
The value to add to the existing value if
key
exists.
Returns: Returns the current value associated with key
(after
changes).
/**
* If <code>key</code> exists, <code>putValue</code> is inserted into the map,
* otherwise any existing value is incremented by <code>additionValue</code>.
*
* @param key
* The key of the value to adjust.
* @param putValue
* The value to put if <code>key</code> does not exist.
* @param incrementValue
* The value to add to the existing value if <code>key</code> exists.
* @return Returns the current value associated with <code>key</code> (after
* changes).
*/
@Override
public char putOrAdd(char key, char putValue, char incrementValue) {
assert assigned < mask + 1;
int keyIndex = indexOf(key);
if (indexExists(keyIndex)) {
putValue = ((char) (( values[keyIndex]) + (incrementValue)));
indexReplace(keyIndex, putValue);
} else {
indexInsert(keyIndex, key, putValue);
}
return putValue;
}
Adds incrementValue
to any existing value for the given key
or inserts incrementValue
if key
did not previously exist.
Params: - key – The key of the value to adjust.
- incrementValue – The value to put or add to the existing value if
key
exists.
Returns: Returns the current value associated with key
(after changes).
/**
* Adds <code>incrementValue</code> to any existing value for the given <code>key</code>
* or inserts <code>incrementValue</code> if <code>key</code> did not previously exist.
*
* @param key The key of the value to adjust.
* @param incrementValue The value to put or add to the existing value if <code>key</code> exists.
* @return Returns the current value associated with <code>key</code> (after changes).
*/
@Override
public char addTo(char key, char incrementValue)
{
return putOrAdd(key, incrementValue, incrementValue);
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public char remove(char key) {
final int mask = this.mask;
if (((key) == 0)) {
hasEmptyKey = false;
char previousValue = values[mask + 1];
values[mask + 1] = ((char) 0);
return previousValue;
} else {
final char[] keys = this.keys;
int slot = hashKey(key) & mask;
char existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
final char previousValue = values[slot];
shiftConflictingKeys(slot);
return previousValue;
}
slot = (slot + 1) & mask;
}
return ((char) 0);
}
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public int removeAll(CharContainer 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 CharLookupContainer) {
if (hasEmptyKey) {
if (other.contains(((char) 0))) {
hasEmptyKey = false;
values[mask + 1] = ((char) 0);
}
}
final char[] keys = this.keys;
for (int slot = 0, max = this.mask; slot <= max;) {
char existing;
if (!((existing = keys[slot]) == 0) && other.contains(existing)) {
// Shift, do not increment slot.
shiftConflictingKeys(slot);
} else {
slot++;
}
}
} else {
for (CharCursor c : other) {
this.remove( c.value);
}
}
return before - size();
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public int removeAll(CharCharPredicate predicate) {
final int before = size();
final int mask = this.mask;
if (hasEmptyKey) {
if (predicate.apply(((char) 0), values[mask + 1])) {
hasEmptyKey = false;
values[mask + 1] = ((char) 0);
}
}
final char[] keys = this.keys;
final char[] values = this.values;
for (int slot = 0; slot <= mask;) {
char existing;
if (!((existing = keys[slot]) == 0) &&
predicate.apply(existing, values[slot])) {
// Shift, do not increment slot.
shiftConflictingKeys(slot);
} else {
slot++;
}
}
return before - size();
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public int removeAll(CharPredicate predicate) {
final int before = size();
if (hasEmptyKey) {
if (predicate.apply(((char) 0))) {
hasEmptyKey = false;
values[mask + 1] = ((char) 0);
}
}
final char[] keys = this.keys;
for (int slot = 0, max = this.mask; slot <= max;) {
char existing;
if (!((existing = keys[slot]) == 0) &&
predicate.apply(existing)) {
// Shift, do not increment slot.
shiftConflictingKeys(slot);
} else {
slot++;
}
}
return before - size();
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public char get(char key) {
if (((key) == 0)) {
return hasEmptyKey ? values[mask + 1] : ((char) 0);
} else {
final char[] keys = this.keys;
final int mask = this.mask;
int slot = hashKey(key) & mask;
char existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
return values[slot];
}
slot = (slot + 1) & mask;
}
return ((char) 0);
}
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public char getOrDefault(char key, char defaultValue) {
if (((key) == 0)) {
return hasEmptyKey ? values[mask + 1] : defaultValue;
} else {
final char[] keys = this.keys;
final int mask = this.mask;
int slot = hashKey(key) & mask;
char existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
return values[slot];
}
slot = (slot + 1) & mask;
}
return defaultValue;
}
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public boolean containsKey(char key) {
if (((key) == 0)) {
return hasEmptyKey;
} else {
final char[] keys = this.keys;
final int mask = this.mask;
int slot = hashKey(key) & mask;
char existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
return true;
}
slot = (slot + 1) & mask;
}
return false;
}
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public int indexOf(char key) {
final int mask = this.mask;
if (((key) == 0)) {
return hasEmptyKey ? mask + 1 : ~(mask + 1);
} else {
final char[] keys = this.keys;
int slot = hashKey(key) & mask;
char existing;
while (!((existing = keys[slot]) == 0)) {
if (((existing) == ( key))) {
return slot;
}
slot = (slot + 1) & mask;
}
return ~slot;
}
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public boolean indexExists(int index) {
assert index < 0 ||
(index >= 0 && index <= mask) ||
(index == mask + 1 && hasEmptyKey);
return index >= 0;
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public char indexGet(int index) {
assert index >= 0 : "The index must point at an existing key.";
assert index <= mask ||
(index == mask + 1 && hasEmptyKey);
return values[index];
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public char indexReplace(int index, char newValue) {
assert index >= 0 : "The index must point at an existing key.";
assert index <= mask ||
(index == mask + 1 && hasEmptyKey);
char previousValue = values[index];
values[index] = newValue;
return previousValue;
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public void indexInsert(int index, char key, char 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}
/**
* {@inheritDoc}
*/
@Override
public void clear() {
assigned = 0;
hasEmptyKey = false;
Arrays.fill(keys, ((char) 0));
/* */
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public void release() {
assigned = 0;
hasEmptyKey = false;
keys = null;
values = null;
ensureCapacity(Containers.DEFAULT_EXPECTED_ELEMENTS);
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public int size() {
return assigned + (hasEmptyKey ? 1 : 0);
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
public boolean isEmpty() {
return size() == 0;
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
int h = hasEmptyKey ? 0xDEADBEEF : 0;
for (CharCharCursor c : this) {
h += BitMixer.mix(c.key) +
BitMixer.mix(c.value);
}
return h;
}
{@inheritDoc}
/**
* {@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.
/**
* Return true if all keys of some other container exist in this container.
*/
protected boolean equalElements(CharCharHashMap other) {
if (other.size() != size()) {
return false;
}
for (CharCharCursor c : other) {
char key = c.key;
if (!containsKey(key) ||
!((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.
Params: - expectedElements – The total number of keys, inclusive.
/**
* 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 char[] prevKeys = this.keys;
final char[] prevValues = this.values;
allocateBuffers(minBufferSize(expectedElements, loadFactor));
if (prevKeys != null && !isEmpty()) {
rehash(prevKeys, prevValues);
}
}
}
An iterator implementation for CharCharHashMap.iterator
. /**
* An iterator implementation for {@link #iterator}.
*/
private final class EntryIterator extends AbstractIterator<CharCharCursor> {
private final CharCharCursor cursor;
private final int max = mask + 1;
private int slot = -1;
public EntryIterator() {
cursor = new CharCharCursor();
}
@Override
protected CharCharCursor fetch() {
if (slot < max) {
char existing;
for (slot++; slot < max; slot++) {
if (!((existing = keys[slot]) == 0)) {
cursor.index = slot;
cursor.key = existing;
cursor.value = values[slot];
return cursor;
}
}
}
if (slot == max && hasEmptyKey) {
cursor.index = slot;
cursor.key = ((char) 0);
cursor.value = values[max];
slot++;
return cursor;
}
return done();
}
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public Iterator<CharCharCursor> iterator() {
return new EntryIterator();
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public <T extends CharCharProcedure> T forEach(T procedure) {
final char[] keys = this.keys;
final char[] values = this.values;
if (hasEmptyKey) {
procedure.apply(((char) 0), 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}
/**
* {@inheritDoc}
*/
@Override
public <T extends CharCharPredicate> T forEach(T predicate) {
final char[] keys = this.keys;
final char[] values = this.values;
if (hasEmptyKey) {
if (!predicate.apply(((char) 0), 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 ObjectLookupContainer
. /**
* 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.
/**
* A view of the keys inside this hash map.
*/
public final class KeysContainer extends AbstractCharCollection
implements CharLookupContainer {
private final CharCharHashMap owner = CharCharHashMap.this;
@Override
public boolean contains(char e) {
return owner.containsKey(e);
}
@Override
public <T extends CharProcedure> T forEach(final T procedure) {
owner.forEach(new CharCharProcedure() {
@Override
public void apply(char key, char value) {
procedure.apply(key);
}
});
return procedure;
}
@Override
public <T extends CharPredicate> T forEach(final T predicate) {
owner.forEach(new CharCharPredicate() {
@Override
public boolean apply(char key, char value) {
return predicate.apply(key);
}
});
return predicate;
}
@Override
public boolean isEmpty() {
return owner.isEmpty();
}
@Override
public Iterator<CharCursor> 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(CharPredicate predicate) {
return owner.removeAll(predicate);
}
@Override
public int removeAll(final char 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.
/**
* An iterator over the set of assigned keys.
*/
private final class KeysIterator extends AbstractIterator<CharCursor> {
private final CharCursor cursor;
private final int max = mask + 1;
private int slot = -1;
public KeysIterator() {
cursor = new CharCursor();
}
@Override
protected CharCursor fetch() {
if (slot < max) {
char 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 = ((char) 0);
slot++;
return cursor;
}
return done();
}
}
Returns: Returns a container with all values stored in this map.
/**
* @return Returns a container with all values stored in this map.
*/
@Override
public CharCollection values() {
return new ValuesContainer();
}
A view over the set of values of this map.
/**
* A view over the set of values of this map.
*/
private final class ValuesContainer extends AbstractCharCollection {
private final CharCharHashMap owner = CharCharHashMap.this;
@Override
public int size() {
return owner.size();
}
@Override
public boolean isEmpty() {
return owner.isEmpty();
}
@Override
public boolean contains(char value) {
for (CharCharCursor c : owner) {
if (((c.value) == (value))) {
return true;
}
}
return false;
}
@Override
public <T extends CharProcedure> T forEach(T procedure) {
for (CharCharCursor c : owner) {
procedure.apply(c.value);
}
return procedure;
}
@Override
public <T extends CharPredicate> T forEach(T predicate) {
for (CharCharCursor c : owner) {
if (!predicate.apply(c.value)) {
break;
}
}
return predicate;
}
@Override
public Iterator<CharCursor> iterator() {
return new ValuesIterator();
}
@Override
public int removeAll(final char e) {
return owner.removeAll(new CharCharPredicate() {
@Override
public boolean apply(char key, char value) {
return ((value) == (e));
}
});
}
@Override
public int removeAll(final CharPredicate predicate) {
return owner.removeAll(new CharCharPredicate() {
@Override
public boolean apply(char key, char 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.
/**
* An iterator over the set of assigned values.
*/
private final class ValuesIterator extends AbstractIterator<CharCursor> {
private final CharCursor cursor;
private final int max = mask + 1;
private int slot = -1;
public ValuesIterator() {
cursor = new CharCursor();
}
@Override
protected CharCursor fetch() {
if (slot < max) {
for (slot++; slot < max; slot++) {
if (!(( keys[slot]) == 0)) {
cursor.index = slot;
cursor.value = values[slot];
return cursor;
}
}
}
if (slot == max && hasEmptyKey) {
cursor.index = slot;
cursor.value = values[max];
slot++;
return cursor;
}
return done();
}
}
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
public CharCharHashMap clone() {
try {
/* */
CharCharHashMap cloned = (CharCharHashMap) 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.
/**
* 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 (CharCharCursor 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 CharBufferVisualizer.visualizeKeyDistribution(keys, mask, characters);
}
Creates a hash map from two index-aligned arrays of key-value pairs.
/**
* Creates a hash map from two index-aligned arrays of key-value pairs.
*/
public static CharCharHashMap from(char[] keys, char[] values) {
if (keys.length != values.length) {
throw new IllegalArgumentException("Arrays of keys and values must have an identical length.");
}
CharCharHashMap map = new CharCharHashMap(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 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.
/**
* Returns a hash code for the given key.
*
* <p>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.</p>
*
* <p>The output from this function should evenly distribute keys across the
* entire integer range.</p>
*/
protected
int hashKey(char 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.
/**
* 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.
/**
* Rehash from old buffers to new buffers.
*/
protected void rehash(char[] fromKeys, char[] fromValues) {
assert fromKeys.length == fromValues.length &&
HashContainers.checkPowerOfTwo(fromKeys.length - 1);
// Rehash all stored key/value pairs into the new buffers.
final char[] keys = this.keys;
final char[] values = this.values;
final int mask = this.mask;
char 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).
/**
* 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.
char[] prevKeys = this.keys;
char[] prevValues = this.values;
try {
int emptyElementSlot = 1;
this.keys = (new char [arraySize + emptyElementSlot]);
this.values = (new char [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.
/**
* 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, char pendingKey, char 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 char[] prevKeys = this.keys;
final char[] prevValues = 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
.
/**
* Shift all the slot-conflicting keys and values allocated to
* (and including) <code>slot</code>.
*/
protected void shiftConflictingKeys(int gapSlot) {
final char[] keys = this.keys;
final char[] values = 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 char 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] = ((char) 0);
values[gapSlot] = ((char) 0);
assigned--;
}
}