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Utilities for the Network project.
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/*******************************************************************************
* Copyright 2010 Mario Zechner ([email protected]), Nathan Sweet ([email protected])
*
* 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.
*/
// slightly tweaked from libGDX, by dorkbox, llc
package dorkbox.util.collections;
import dorkbox.util.MathUtil;
import java.util.Iterator;
import java.util.NoSuchElementException;
/** An unordered map that uses int keys. This implementation is a cuckoo hash map using 3 hashes, random walking, and a small stash
* for problematic keys. Null values are allowed. No allocation is done except when growing the table size.
*
* This map performs very fast get, containsKey, and remove (typically O(1), worst case O(log(n))). Put may be a bit slower,
* depending on hash collisions. Load factors greater than 0.91 greatly increase the chances the map will have to rehash to the
* next higher POT size.
* @author Nathan Sweet */
@SuppressWarnings({"rawtypes", "unchecked"})
public class IntMap {
@SuppressWarnings("unused")
private static final int PRIME1 = 0xbe1f14b1;
private static final int PRIME2 = 0xb4b82e39;
private static final int PRIME3 = 0xced1c241;
private static final int EMPTY = 0;
public int size;
int[] keyTable;
V[] valueTable;
int capacity, stashSize;
V zeroValue;
boolean hasZeroValue;
private float loadFactor;
private int hashShift, mask, threshold;
private int stashCapacity;
private int pushIterations;
private Entries entries1, entries2;
private Values values1, values2;
private Keys keys1, keys2;
/** Creates a new map with an initial capacity of 32 and a load factor of 0.8. This map will hold 25 items before growing the
* backing table. */
public IntMap () {
this(32, 0.8f);
}
/** Creates a new map with a load factor of 0.8. This map will hold initialCapacity * 0.8 items before growing the backing
* table. */
public IntMap (int initialCapacity) {
this(initialCapacity, 0.8f);
}
/** Creates a new map with the specified initial capacity and load factor. This map will hold initialCapacity * loadFactor items
* before growing the backing table. */
public IntMap (int initialCapacity, float loadFactor) {
if (initialCapacity < 0) {
throw new IllegalArgumentException("initialCapacity must be >= 0: " + initialCapacity);
}
if (this.capacity > 1 << 30) {
throw new IllegalArgumentException("initialCapacity is too large: " + initialCapacity);
}
this.capacity = MathUtil.nextPowerOfTwo(initialCapacity);
if (loadFactor <= 0) {
throw new IllegalArgumentException("loadFactor must be > 0: " + loadFactor);
}
this.loadFactor = loadFactor;
this.threshold = (int)(this.capacity * loadFactor);
this.mask = this.capacity - 1;
this.hashShift = 31 - Integer.numberOfTrailingZeros(this.capacity);
this.stashCapacity = Math.max(3, (int)Math.ceil(Math.log(this.capacity)) * 2);
this.pushIterations = Math.max(Math.min(this.capacity, 8), (int)Math.sqrt(this.capacity) / 8);
this.keyTable = new int[this.capacity + this.stashCapacity];
this.valueTable = (V[])new Object[this.keyTable.length];
}
public V put (int key, V value) {
if (key == 0) {
V oldValue = this.zeroValue;
this.zeroValue = value;
if (!this.hasZeroValue) {
this.hasZeroValue = true;
this.size++;
}
return oldValue;
}
int[] keyTable = this.keyTable;
// Check for existing keys.
int index1 = key & this.mask;
int key1 = keyTable[index1];
if (key1 == key) {
V oldValue = this.valueTable[index1];
this.valueTable[index1] = value;
return oldValue;
}
int index2 = hash2(key);
int key2 = keyTable[index2];
if (key2 == key) {
V oldValue = this.valueTable[index2];
this.valueTable[index2] = value;
return oldValue;
}
int index3 = hash3(key);
int key3 = keyTable[index3];
if (key3 == key) {
V oldValue = this.valueTable[index3];
this.valueTable[index3] = value;
return oldValue;
}
// Update key in the stash.
for (int i = this.capacity, n = i + this.stashSize; i < n; i++) {
if (keyTable[i] == key) {
V oldValue = this.valueTable[i];
this.valueTable[i] = value;
return oldValue;
}
}
// Check for empty buckets.
if (key1 == EMPTY) {
keyTable[index1] = key;
this.valueTable[index1] = value;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return null;
}
if (key2 == EMPTY) {
keyTable[index2] = key;
this.valueTable[index2] = value;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return null;
}
if (key3 == EMPTY) {
keyTable[index3] = key;
this.valueTable[index3] = value;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return null;
}
push(key, value, index1, key1, index2, key2, index3, key3);
return null;
}
public void putAll (IntMap map) {
for (Entry entry : map.entries()) {
put(entry.key, entry.value);
}
}
/** Skips checks for existing keys. */
private void putResize (int key, V value) {
if (key == 0) {
this.zeroValue = value;
this.hasZeroValue = true;
return;
}
// Check for empty buckets.
int index1 = key & this.mask;
int key1 = this.keyTable[index1];
if (key1 == EMPTY) {
this.keyTable[index1] = key;
this.valueTable[index1] = value;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return;
}
int index2 = hash2(key);
int key2 = this.keyTable[index2];
if (key2 == EMPTY) {
this.keyTable[index2] = key;
this.valueTable[index2] = value;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return;
}
int index3 = hash3(key);
int key3 = this.keyTable[index3];
if (key3 == EMPTY) {
this.keyTable[index3] = key;
this.valueTable[index3] = value;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return;
}
push(key, value, index1, key1, index2, key2, index3, key3);
}
private void push (int insertKey, V insertValue, int index1, int key1, int index2, int key2, int index3, int key3) {
int[] keyTable = this.keyTable;
V[] valueTable = this.valueTable;
int mask = this.mask;
// Push keys until an empty bucket is found.
int evictedKey;
V evictedValue;
int i = 0, pushIterations = this.pushIterations;
do {
// Replace the key and value for one of the hashes.
switch (MathUtil.randomInt(2)) {
case 0:
evictedKey = key1;
evictedValue = valueTable[index1];
keyTable[index1] = insertKey;
valueTable[index1] = insertValue;
break;
case 1:
evictedKey = key2;
evictedValue = valueTable[index2];
keyTable[index2] = insertKey;
valueTable[index2] = insertValue;
break;
default:
evictedKey = key3;
evictedValue = valueTable[index3];
keyTable[index3] = insertKey;
valueTable[index3] = insertValue;
break;
}
// If the evicted key hashes to an empty bucket, put it there and stop.
index1 = evictedKey & mask;
key1 = keyTable[index1];
if (key1 == EMPTY) {
keyTable[index1] = evictedKey;
valueTable[index1] = evictedValue;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return;
}
index2 = hash2(evictedKey);
key2 = keyTable[index2];
if (key2 == EMPTY) {
keyTable[index2] = evictedKey;
valueTable[index2] = evictedValue;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return;
}
index3 = hash3(evictedKey);
key3 = keyTable[index3];
if (key3 == EMPTY) {
keyTable[index3] = evictedKey;
valueTable[index3] = evictedValue;
if (this.size++ >= this.threshold) {
resize(this.capacity << 1);
}
return;
}
if (++i == pushIterations) {
break;
}
insertKey = evictedKey;
insertValue = evictedValue;
} while (true);
putStash(evictedKey, evictedValue);
}
private void putStash (int key, V value) {
if (this.stashSize == this.stashCapacity) {
// Too many pushes occurred and the stash is full, increase the table size.
resize(this.capacity << 1);
put(key, value);
return;
}
// Store key in the stash.
int index = this.capacity + this.stashSize;
this.keyTable[index] = key;
this.valueTable[index] = value;
this.stashSize++;
this.size++;
}
public V get (int key) {
if (key == 0) {
if (!this.hasZeroValue) {
return null;
}
return this.zeroValue;
}
int index = key & this.mask;
if (this.keyTable[index] != key) {
index = hash2(key);
if (this.keyTable[index] != key) {
index = hash3(key);
if (this.keyTable[index] != key) {
return getStash(key, null);
}
}
}
return this.valueTable[index];
}
public V get (int key, V defaultValue) {
if (key == 0) {
if (!this.hasZeroValue) {
return defaultValue;
}
return this.zeroValue;
}
int index = key & this.mask;
if (this.keyTable[index] != key) {
index = hash2(key);
if (this.keyTable[index] != key) {
index = hash3(key);
if (this.keyTable[index] != key) {
return getStash(key, defaultValue);
}
}
}
return this.valueTable[index];
}
private V getStash (int key, V defaultValue) {
int[] keyTable = this.keyTable;
for (int i = this.capacity, n = i + this.stashSize; i < n; i++) {
if (keyTable[i] == key) {
return this.valueTable[i];
}
}
return defaultValue;
}
public V remove (int key) {
if (key == 0) {
if (!this.hasZeroValue) {
return null;
}
V oldValue = this.zeroValue;
this.zeroValue = null;
this.hasZeroValue = false;
this.size--;
return oldValue;
}
int index = key & this.mask;
if (this.keyTable[index] == key) {
this.keyTable[index] = EMPTY;
V oldValue = this.valueTable[index];
this.valueTable[index] = null;
this.size--;
return oldValue;
}
index = hash2(key);
if (this.keyTable[index] == key) {
this.keyTable[index] = EMPTY;
V oldValue = this.valueTable[index];
this.valueTable[index] = null;
this.size--;
return oldValue;
}
index = hash3(key);
if (this.keyTable[index] == key) {
this.keyTable[index] = EMPTY;
V oldValue = this.valueTable[index];
this.valueTable[index] = null;
this.size--;
return oldValue;
}
return removeStash(key);
}
V removeStash (int key) {
int[] keyTable = this.keyTable;
for (int i = this.capacity, n = i + this.stashSize; i < n; i++) {
if (keyTable[i] == key) {
V oldValue = this.valueTable[i];
removeStashIndex(i);
this.size--;
return oldValue;
}
}
return null;
}
void removeStashIndex (int index) {
// If the removed location was not last, move the last tuple to the removed location.
this.stashSize--;
int lastIndex = this.capacity + this.stashSize;
if (index < lastIndex) {
this.keyTable[index] = this.keyTable[lastIndex];
this.valueTable[index] = this.valueTable[lastIndex];
this.valueTable[lastIndex] = null;
} else {
this.valueTable[index] = null;
}
}
public void clear () {
int[] keyTable = this.keyTable;
V[] valueTable = this.valueTable;
for (int i = this.capacity + this.stashSize; i-- > 0;) {
keyTable[i] = EMPTY;
valueTable[i] = null;
}
this.size = 0;
this.stashSize = 0;
this.zeroValue = null;
this.hasZeroValue = false;
}
/** Returns true if the specified value is in the map. Note this traverses the entire map and compares every value, which may be
* an expensive operation.
* @param identity If true, uses == to compare the specified value with values in the map. If false, uses
* {@link #equals(Object)}. */
public boolean containsValue (Object value, boolean identity) {
V[] valueTable = this.valueTable;
if (value == null) {
if (this.hasZeroValue && this.zeroValue == null) {
return true;
}
int[] keyTable = this.keyTable;
for (int i = this.capacity + this.stashSize; i-- > 0;) {
if (keyTable[i] != EMPTY && valueTable[i] == null) {
return true;
}
}
} else if (identity) {
if (value == this.zeroValue) {
return true;
}
for (int i = this.capacity + this.stashSize; i-- > 0;) {
if (valueTable[i] == value) {
return true;
}
}
} else {
if (this.hasZeroValue && value.equals(this.zeroValue)) {
return true;
}
for (int i = this.capacity + this.stashSize; i-- > 0;) {
if (value.equals(valueTable[i])) {
return true;
}
}
}
return false;
}
public boolean containsKey (int key) {
if (key == 0) {
return this.hasZeroValue;
}
int index = key & this.mask;
if (this.keyTable[index] != key) {
index = hash2(key);
if (this.keyTable[index] != key) {
index = hash3(key);
if (this.keyTable[index] != key) {
return containsKeyStash(key);
}
}
}
return true;
}
private boolean containsKeyStash (int key) {
int[] keyTable = this.keyTable;
for (int i = this.capacity, n = i + this.stashSize; i < n; i++) {
if (keyTable[i] == key) {
return true;
}
}
return false;
}
/** Returns the key for the specified value, or notFound if it is not in the map. Note this traverses the entire map
* and compares every value, which may be an expensive operation.
* @param identity If true, uses == to compare the specified value with values in the map. If false, uses
* {@link #equals(Object)}. */
public int findKey (Object value, boolean identity, int notFound) {
V[] valueTable = this.valueTable;
if (value == null) {
if (this.hasZeroValue && this.zeroValue == null) {
return 0;
}
int[] keyTable = this.keyTable;
for (int i = this.capacity + this.stashSize; i-- > 0;) {
if (keyTable[i] != EMPTY && valueTable[i] == null) {
return keyTable[i];
}
}
} else if (identity) {
if (value == this.zeroValue) {
return 0;
}
for (int i = this.capacity + this.stashSize; i-- > 0;) {
if (valueTable[i] == value) {
return this.keyTable[i];
}
}
} else {
if (this.hasZeroValue && value.equals(this.zeroValue)) {
return 0;
}
for (int i = this.capacity + this.stashSize; i-- > 0;) {
if (value.equals(valueTable[i])) {
return this.keyTable[i];
}
}
}
return notFound;
}
/** Increases the size of the backing array to acommodate the specified number of additional items. Useful before adding many
* items to avoid multiple backing array resizes. */
public void ensureCapacity (int additionalCapacity) {
int sizeNeeded = this.size + additionalCapacity;
if (sizeNeeded >= this.threshold) {
resize(MathUtil.nextPowerOfTwo((int) (sizeNeeded / this.loadFactor)));
}
}
private void resize (int newSize) {
int oldEndIndex = this.capacity + this.stashSize;
this.capacity = newSize;
this.threshold = (int)(newSize * this.loadFactor);
this.mask = newSize - 1;
this.hashShift = 31 - Integer.numberOfTrailingZeros(newSize);
this.stashCapacity = Math.max(3, (int)Math.ceil(Math.log(newSize)) * 2);
this.pushIterations = Math.max(Math.min(newSize, 8), (int)Math.sqrt(newSize) / 8);
int[] oldKeyTable = this.keyTable;
V[] oldValueTable = this.valueTable;
this.keyTable = new int[newSize + this.stashCapacity];
this.valueTable = (V[])new Object[newSize + this.stashCapacity];
this.size = this.hasZeroValue ? 1 : 0;
this.stashSize = 0;
for (int i = 0; i < oldEndIndex; i++) {
int key = oldKeyTable[i];
if (key != EMPTY) {
putResize(key, oldValueTable[i]);
}
}
}
private int hash2 (int h) {
h *= PRIME2;
return (h ^ h >>> this.hashShift) & this.mask;
}
private int hash3 (int h) {
h *= PRIME3;
return (h ^ h >>> this.hashShift) & this.mask;
}
@Override
public String toString () {
if (this.size == 0) {
return "[]";
}
StringBuilder buffer = new StringBuilder(32);
buffer.append('[');
int[] keyTable = this.keyTable;
V[] valueTable = this.valueTable;
int i = keyTable.length;
if (this.hasZeroValue) {
buffer.append("0=");
buffer.append(this.zeroValue);
} else {
while (i-- > 0) {
int key = keyTable[i];
if (key == EMPTY) {
continue;
}
buffer.append(key);
buffer.append('=');
buffer.append(valueTable[i]);
break;
}
}
while (i-- > 0) {
int key = keyTable[i];
if (key == EMPTY) {
continue;
}
buffer.append(", ");
buffer.append(key);
buffer.append('=');
buffer.append(valueTable[i]);
}
buffer.append(']');
return buffer.toString();
}
/** Returns an iterator for the entries in the map. Remove is supported. Note that the same iterator instance is returned each
* time this method is called. Use the {@link Entries} constructor for nested or multithreaded iteration. */
public Entries entries () {
if (this.entries1 == null) {
this.entries1 = new Entries(this);
this.entries2 = new Entries(this);
}
if (!this.entries1.valid) {
this.entries1.reset();
this.entries1.valid = true;
this.entries2.valid = false;
return this.entries1;
}
this.entries2.reset();
this.entries2.valid = true;
this.entries1.valid = false;
return this.entries2;
}
/** Returns an iterator for the values in the map. Remove is supported. Note that the same iterator instance is returned each
* time this method is called. Use the {@link Entries} constructor for nested or multithreaded iteration. */
public Values values () {
if (this.values1 == null) {
this.values1 = new Values(this);
this.values2 = new Values(this);
}
if (!this.values1.valid) {
this.values1.reset();
this.values1.valid = true;
this.values2.valid = false;
return this.values1;
}
this.values2.reset();
this.values2.valid = true;
this.values1.valid = false;
return this.values2;
}
/** Returns an iterator for the keys in the map. Remove is supported. Note that the same iterator instance is returned each time
* this method is called. Use the {@link Entries} constructor for nested or multithreaded iteration. */
public Keys keys () {
if (this.keys1 == null) {
this.keys1 = new Keys(this);
this.keys2 = new Keys(this);
}
if (!this.keys1.valid) {
this.keys1.reset();
this.keys1.valid = true;
this.keys2.valid = false;
return this.keys1;
}
this.keys2.reset();
this.keys2.valid = true;
this.keys1.valid = false;
return this.keys2;
}
static public class Entry {
public int key;
public V value;
@Override
public String toString () {
return this.key + "=" + this.value;
}
}
static private class MapIterator {
static final int INDEX_ILLEGAL = -2;
static final int INDEX_ZERO = -1;
public boolean hasNext;
final IntMap map;
int nextIndex, currentIndex;
boolean valid = true;
public MapIterator (IntMap map) {
this.map = map;
reset();
}
public void reset () {
this.currentIndex = INDEX_ILLEGAL;
this.nextIndex = INDEX_ZERO;
if (this.map.hasZeroValue) {
this.hasNext = true;
} else {
findNextIndex();
}
}
void findNextIndex () {
this.hasNext = false;
int[] keyTable = this.map.keyTable;
for (int n = this.map.capacity + this.map.stashSize; ++this.nextIndex < n;) {
if (keyTable[this.nextIndex] != EMPTY) {
this.hasNext = true;
break;
}
}
}
public void remove () {
if (this.currentIndex == INDEX_ZERO && this.map.hasZeroValue) {
this.map.zeroValue = null;
this.map.hasZeroValue = false;
} else if (this.currentIndex < 0) {
throw new IllegalStateException("next must be called before remove.");
} else if (this.currentIndex >= this.map.capacity) {
this.map.removeStashIndex(this.currentIndex);
} else {
this.map.keyTable[this.currentIndex] = EMPTY;
this.map.valueTable[this.currentIndex] = null;
}
this.currentIndex = INDEX_ILLEGAL;
this.map.size--;
}
}
static public class Entries extends MapIterator implements Iterable>, Iterator> {
private Entry entry = new Entry();
public Entries (IntMap map) {
super(map);
}
/** Note the same entry instance is returned each time this method is called. */
@Override
public Entry next () {
if (!this.hasNext) {
throw new NoSuchElementException();
}
if (!this.valid) {
throw new RuntimeException("#iterator() cannot be used nested.");
}
int[] keyTable = this.map.keyTable;
if (this.nextIndex == INDEX_ZERO) {
this.entry.key = 0;
this.entry.value = this.map.zeroValue;
} else {
this.entry.key = keyTable[this.nextIndex];
this.entry.value = this.map.valueTable[this.nextIndex];
}
this.currentIndex = this.nextIndex;
findNextIndex();
return this.entry;
}
@Override
public boolean hasNext () {
return this.hasNext;
}
@Override
public Iterator> iterator () {
return this;
}
}
static public class Values extends MapIterator implements Iterable, Iterator {
public Values (IntMap map) {
super(map);
}
@Override
public boolean hasNext () {
return this.hasNext;
}
@Override
public V next () {
if (!this.hasNext) {
throw new NoSuchElementException();
}
if (!this.valid) {
throw new RuntimeException("#iterator() cannot be used nested.");
}
V value;
if (this.nextIndex == INDEX_ZERO) {
value = this.map.zeroValue;
} else {
value = this.map.valueTable[this.nextIndex];
}
this.currentIndex = this.nextIndex;
findNextIndex();
return value;
}
@Override
public Iterator iterator () {
return this;
}
/** Returns a new array containing the remaining values. */
// public Array toArray () {
// Array array = new Array(true, map.size);
// while (hasNext) {
// array.add(next());
// }
// return array;
// }
}
static public class Keys extends MapIterator {
public Keys (IntMap map) {
super(map);
}
public int next () {
if (!this.hasNext) {
throw new NoSuchElementException();
}
if (!this.valid) {
throw new RuntimeException("#iterator() cannot be used nested.");
}
int key = this.nextIndex == INDEX_ZERO ? 0 : this.map.keyTable[this.nextIndex];
this.currentIndex = this.nextIndex;
findNextIndex();
return key;
}
/** Returns a new array containing the remaining keys. */
public IntArray toArray () {
IntArray array = new IntArray(true, this.map.size);
while (this.hasNext) {
array.add(next());
}
return array;
}
}
}
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