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ported IntFloatMap

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Robinson 2023-08-01 20:42:23 -06:00
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src/dorkbox/collections/IntFloatMap.java
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/*******************************************************************************
* Copyright 2011 LibGDX.
* Mario Zechner <badlogicgames@gmail.com>
* Nathan Sweet <nathan.sweet@gmail.com>
*
* 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 dorkbox.collections;
import java.util.Iterator;
import java.util.NoSuchElementException;
/** An unordered map where the keys are ints and values are floats. This implementation is a cuckoo hash map using 3 hashes, random
* walking, and a small stash for problematic keys. Null keys are not allowed. No allocation is done except when growing the table
* size. <br>
* <br>
* 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 */
public class IntFloatMap implements Iterable<IntFloatMap.Entry> {
public static final String version = Collections.version;
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;
float[] valueTable;
int capacity, stashSize;
float 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 51 and a load factor of 0.8. */
public IntFloatMap () {
this(51, 0.8f);
}
/** Creates a new map with a load factor of 0.8.
* @param initialCapacity If not a power of two, it is increased to the next nearest power of two. */
public IntFloatMap (int initialCapacity) {
this(initialCapacity, 0.8f);
}
/** Creates a new map with the specified initial capacity and load factor. This map will hold initialCapacity items before
* growing the backing table.
* @param initialCapacity If not a power of two, it is increased to the next nearest power of two. */
public IntFloatMap (int initialCapacity, float loadFactor) {
if (initialCapacity < 0) throw new IllegalArgumentException("initialCapacity must be >= 0: " + initialCapacity);
initialCapacity = Collections.nextPowerOfTwo((int)Math.ceil(initialCapacity / loadFactor));
if (initialCapacity > 1 << 30) throw new IllegalArgumentException("initialCapacity is too large: " + initialCapacity);
capacity = initialCapacity;
if (loadFactor <= 0) throw new IllegalArgumentException("loadFactor must be > 0: " + loadFactor);
this.loadFactor = loadFactor;
threshold = (int)(capacity * loadFactor);
mask = capacity - 1;
hashShift = 31 - Integer.numberOfTrailingZeros(capacity);
stashCapacity = Math.max(3, (int)Math.ceil(Math.log(capacity)) * 2);
pushIterations = Math.max(Math.min(capacity, 8), (int)Math.sqrt(capacity) / 8);
keyTable = new int[capacity + stashCapacity];
valueTable = new float[keyTable.length];
}
/** Creates a new map identical to the specified map. */
public IntFloatMap (IntFloatMap map) {
this((int)Math.floor(map.capacity * map.loadFactor), map.loadFactor);
stashSize = map.stashSize;
System.arraycopy(map.keyTable, 0, keyTable, 0, map.keyTable.length);
System.arraycopy(map.valueTable, 0, valueTable, 0, map.valueTable.length);
size = map.size;
zeroValue = map.zeroValue;
hasZeroValue = map.hasZeroValue;
}
public void put (int key, float value) {
if (key == 0) {
zeroValue = value;
if (!hasZeroValue) {
hasZeroValue = true;
size++;
}
return;
}
int[] keyTable = this.keyTable;
// Check for existing keys.
int index1 = key & mask;
int key1 = keyTable[index1];
if (key == key1) {
valueTable[index1] = value;
return;
}
int index2 = hash2(key);
int key2 = keyTable[index2];
if (key == key2) {
valueTable[index2] = value;
return;
}
int index3 = hash3(key);
int key3 = keyTable[index3];
if (key == key3) {
valueTable[index3] = value;
return;
}
// Update key in the stash.
for (int i = capacity, n = i + stashSize; i < n; i++) {
if (key == keyTable[i]) {
valueTable[i] = value;
return;
}
}
// Check for empty buckets.
if (key1 == EMPTY) {
keyTable[index1] = key;
valueTable[index1] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
if (key2 == EMPTY) {
keyTable[index2] = key;
valueTable[index2] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
if (key3 == EMPTY) {
keyTable[index3] = key;
valueTable[index3] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
push(key, value, index1, key1, index2, key2, index3, key3);
}
public void putAll (IntFloatMap map) {
for (Entry entry : map.entries())
put(entry.key, entry.value);
}
/** Skips checks for existing keys. */
private void putResize (int key, float value) {
if (key == 0) {
zeroValue = value;
hasZeroValue = true;
return;
}
// Check for empty buckets.
int index1 = key & mask;
int key1 = keyTable[index1];
if (key1 == EMPTY) {
keyTable[index1] = key;
valueTable[index1] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
int index2 = hash2(key);
int key2 = keyTable[index2];
if (key2 == EMPTY) {
keyTable[index2] = key;
valueTable[index2] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
int index3 = hash3(key);
int key3 = keyTable[index3];
if (key3 == EMPTY) {
keyTable[index3] = key;
valueTable[index3] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
push(key, value, index1, key1, index2, key2, index3, key3);
}
private void push (int insertKey, float insertValue, int index1, int key1, int index2, int key2, int index3, int key3) {
int[] keyTable = this.keyTable;
float[] valueTable = this.valueTable;
int mask = this.mask;
// Push keys until an empty bucket is found.
int evictedKey;
float evictedValue;
int i = 0, pushIterations = this.pushIterations;
do {
// Replace the key and value for one of the hashes.
switch (Collections.INSTANCE.random(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 (size++ >= threshold) resize(capacity << 1);
return;
}
index2 = hash2(evictedKey);
key2 = keyTable[index2];
if (key2 == EMPTY) {
keyTable[index2] = evictedKey;
valueTable[index2] = evictedValue;
if (size++ >= threshold) resize(capacity << 1);
return;
}
index3 = hash3(evictedKey);
key3 = keyTable[index3];
if (key3 == EMPTY) {
keyTable[index3] = evictedKey;
valueTable[index3] = evictedValue;
if (size++ >= threshold) resize(capacity << 1);
return;
}
if (++i == pushIterations) break;
insertKey = evictedKey;
insertValue = evictedValue;
} while (true);
putStash(evictedKey, evictedValue);
}
private void putStash (int key, float value) {
if (stashSize == stashCapacity) {
// Too many pushes occurred and the stash is full, increase the table size.
resize(capacity << 1);
putResize(key, value);
return;
}
// Store key in the stash.
int index = capacity + stashSize;
keyTable[index] = key;
valueTable[index] = value;
stashSize++;
size++;
}
/** @param defaultValue Returned if the key was not associated with a value. */
public float get (int key, float defaultValue) {
if (key == 0) {
if (!hasZeroValue) return defaultValue;
return zeroValue;
}
int index = key & mask;
if (keyTable[index] != key) {
index = hash2(key);
if (keyTable[index] != key) {
index = hash3(key);
if (keyTable[index] != key) return getStash(key, defaultValue);
}
}
return valueTable[index];
}
private float getStash (int key, float defaultValue) {
int[] keyTable = this.keyTable;
for (int i = capacity, n = i + stashSize; i < n; i++)
if (key == keyTable[i]) return valueTable[i];
return defaultValue;
}
/** Returns the key's current value and increments the stored value. If the key is not in the map, defaultValue + increment is
* put into the map. */
public float getAndIncrement (int key, float defaultValue, float increment) {
if (key == 0) {
if (hasZeroValue) {
float value = zeroValue;
zeroValue += increment;
return value;
} else {
hasZeroValue = true;
zeroValue = defaultValue + increment;
++size;
return defaultValue;
}
}
int index = key & mask;
if (key != keyTable[index]) {
index = hash2(key);
if (key != keyTable[index]) {
index = hash3(key);
if (key != keyTable[index]) return getAndIncrementStash(key, defaultValue, increment);
}
}
float value = valueTable[index];
valueTable[index] = value + increment;
return value;
}
private float getAndIncrementStash (int key, float defaultValue, float increment) {
int[] keyTable = this.keyTable;
for (int i = capacity, n = i + stashSize; i < n; i++)
if (key == keyTable[i]) {
float value = valueTable[i];
valueTable[i] = value + increment;
return value;
}
put(key, defaultValue + increment);
return defaultValue;
}
public float remove (int key, float defaultValue) {
if (key == 0) {
if (!hasZeroValue) return defaultValue;
hasZeroValue = false;
size--;
return zeroValue;
}
int index = key & mask;
if (key == keyTable[index]) {
keyTable[index] = EMPTY;
float oldValue = valueTable[index];
size--;
return oldValue;
}
index = hash2(key);
if (key == keyTable[index]) {
keyTable[index] = EMPTY;
float oldValue = valueTable[index];
size--;
return oldValue;
}
index = hash3(key);
if (key == keyTable[index]) {
keyTable[index] = EMPTY;
float oldValue = valueTable[index];
size--;
return oldValue;
}
return removeStash(key, defaultValue);
}
float removeStash (int key, float defaultValue) {
int[] keyTable = this.keyTable;
for (int i = capacity, n = i + stashSize; i < n; i++) {
if (key == keyTable[i]) {
float oldValue = valueTable[i];
removeStashIndex(i);
size--;
return oldValue;
}
}
return defaultValue;
}
void removeStashIndex (int index) {
// If the removed location was not last, move the last tuple to the removed location.
stashSize--;
int lastIndex = capacity + stashSize;
if (index < lastIndex) {
keyTable[index] = keyTable[lastIndex];
valueTable[index] = valueTable[lastIndex];
}
}
/** Returns true if the map is empty. */
public boolean isEmpty () {
return size == 0;
}
/** Reduces the size of the backing arrays to be the specified capacity or less. If the capacity is already less, nothing is
* done. If the map contains more items than the specified capacity, the next highest power of two capacity is used instead. */
public void shrink (int maximumCapacity) {
if (maximumCapacity < 0) throw new IllegalArgumentException("maximumCapacity must be >= 0: " + maximumCapacity);
if (size > maximumCapacity) maximumCapacity = size;
if (capacity <= maximumCapacity) return;
maximumCapacity = Collections.nextPowerOfTwo(maximumCapacity);
resize(maximumCapacity);
}
/** Clears the map and reduces the size of the backing arrays to be the specified capacity if they are larger. */
public void clear (int maximumCapacity) {
if (capacity <= maximumCapacity) {
clear();
return;
}
hasZeroValue = false;
size = 0;
resize(maximumCapacity);
}
public void clear () {
if (size == 0) return;
int[] keyTable = this.keyTable;
for (int i = capacity + stashSize; i-- > 0;)
keyTable[i] = EMPTY;
hasZeroValue = false;
size = 0;
stashSize = 0;
}
/** 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. */
public boolean containsValue (float value) {
if (hasZeroValue && zeroValue == value) return true;
int[] keyTable = this.keyTable;
float[] valueTable = this.valueTable;
for (int i = capacity + stashSize; i-- > 0;)
if (keyTable[i] != 0 && valueTable[i] == value) return true;
return 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. */
public boolean containsValue (float value, float epsilon) {
if (hasZeroValue && Math.abs(zeroValue - value) <= epsilon) return true;
float[] valueTable = this.valueTable;
for (int i = capacity + stashSize; i-- > 0;)
if (Math.abs(valueTable[i] - value) <= epsilon) return true;
return false;
}
public boolean containsKey (int key) {
if (key == 0) return hasZeroValue;
int index = key & mask;
if (keyTable[index] != key) {
index = hash2(key);
if (keyTable[index] != key) {
index = hash3(key);
if (keyTable[index] != key) return containsKeyStash(key);
}
}
return true;
}
private boolean containsKeyStash (int key) {
int[] keyTable = this.keyTable;
for (int i = capacity, n = i + stashSize; i < n; i++)
if (key == keyTable[i]) return true;
return false;
}
/** Returns the key for the specified value, or null if it is not in the map. Note this traverses the entire map and compares
* every value, which may be an expensive operation. */
public int findKey (float value, int notFound) {
if (hasZeroValue && zeroValue == value) return 0;
int[] keyTable = this.keyTable;
float[] valueTable = this.valueTable;
for (int i = capacity + stashSize; i-- > 0;)
if (keyTable[i] != 0 && valueTable[i] == value) return keyTable[i];
return notFound;
}
/** Increases the size of the backing array to accommodate the specified number of additional items. Useful before adding many
* items to avoid multiple backing array resizes. */
public void ensureCapacity (int additionalCapacity) {
if (additionalCapacity < 0) throw new IllegalArgumentException("additionalCapacity must be >= 0: " + additionalCapacity);
int sizeNeeded = size + additionalCapacity;
if (sizeNeeded >= threshold) resize(Collections.nextPowerOfTwo((int)Math.ceil(sizeNeeded / loadFactor)));
}
private void resize (int newSize) {
int oldEndIndex = capacity + stashSize;
capacity = newSize;
threshold = (int)(newSize * loadFactor);
mask = newSize - 1;
hashShift = 31 - Integer.numberOfTrailingZeros(newSize);
stashCapacity = Math.max(3, (int)Math.ceil(Math.log(newSize)) * 2);
pushIterations = Math.max(Math.min(newSize, 8), (int)Math.sqrt(newSize) / 8);
int[] oldKeyTable = keyTable;
float[] oldValueTable = valueTable;
keyTable = new int[newSize + stashCapacity];
valueTable = new float[newSize + stashCapacity];
int oldSize = size;
size = hasZeroValue ? 1 : 0;
stashSize = 0;
if (oldSize > 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 >>> hashShift) & mask;
}
private int hash3 (int h) {
h *= PRIME3;
return (h ^ h >>> hashShift) & mask;
}
public int hashCode () {
int h = 0;
if (hasZeroValue) {
h += Float.floatToIntBits(zeroValue);
}
int[] keyTable = this.keyTable;
float[] valueTable = this.valueTable;
for (int i = 0, n = capacity + stashSize; i < n; i++) {
int key = keyTable[i];
if (key != EMPTY) {
h += key * 31;
float value = valueTable[i];
h += Float.floatToIntBits(value);
}
}
return h;
}
public boolean equals (Object obj) {
if (obj == this) return true;
if (!(obj instanceof IntFloatMap)) return false;
IntFloatMap other = (IntFloatMap)obj;
if (other.size != size) return false;
if (other.hasZeroValue != hasZeroValue) return false;
if (hasZeroValue && other.zeroValue != zeroValue) {
return false;
}
int[] keyTable = this.keyTable;
float[] valueTable = this.valueTable;
for (int i = 0, n = capacity + stashSize; i < n; i++) {
int key = keyTable[i];
if (key != EMPTY) {
float otherValue = other.get(key, 0f);
if (otherValue == 0f && !other.containsKey(key)) return false;
float value = valueTable[i];
if (otherValue != value) return false;
}
}
return true;
}
public String toString () {
if (size == 0) return "{}";
StringBuilder buffer = new StringBuilder(32);
buffer.append('{');
int[] keyTable = this.keyTable;
float[] valueTable = this.valueTable;
int i = keyTable.length;
if (hasZeroValue) {
buffer.append("0=");
buffer.append(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();
}
public Iterator<Entry> iterator () {
return entries();
}
/** 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 (entries1 == null) {
entries1 = new Entries(this);
entries2 = new Entries(this);
}
if (!entries1.valid) {
entries1.reset();
entries1.valid = true;
entries2.valid = false;
return entries1;
}
entries2.reset();
entries2.valid = true;
entries1.valid = false;
return 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 (values1 == null) {
values1 = new Values(this);
values2 = new Values(this);
}
if (!values1.valid) {
values1.reset();
values1.valid = true;
values2.valid = false;
return values1;
}
values2.reset();
values2.valid = true;
values1.valid = false;
return 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 (keys1 == null) {
keys1 = new Keys(this);
keys2 = new Keys(this);
}
if (!keys1.valid) {
keys1.reset();
keys1.valid = true;
keys2.valid = false;
return keys1;
}
keys2.reset();
keys2.valid = true;
keys1.valid = false;
return keys2;
}
static public class Entry {
public int key;
public float value;
public String toString () {
return key + "=" + value;
}
}
static private class MapIterator {
static final int INDEX_ILLEGAL = -2;
static final int INDEX_ZERO = -1;
public boolean hasNext;
final IntFloatMap map;
int nextIndex, currentIndex;
boolean valid = true;
public MapIterator (IntFloatMap map) {
this.map = map;
reset();
}
public void reset () {
currentIndex = INDEX_ILLEGAL;
nextIndex = INDEX_ZERO;
if (map.hasZeroValue)
hasNext = true;
else
findNextIndex();
}
void findNextIndex () {
hasNext = false;
int[] keyTable = map.keyTable;
for (int n = map.capacity + map.stashSize; ++nextIndex < n;) {
if (keyTable[nextIndex] != EMPTY) {
hasNext = true;
break;
}
}
}
public void remove () {
if (currentIndex == INDEX_ZERO && map.hasZeroValue) {
map.hasZeroValue = false;
} else if (currentIndex < 0) {
throw new IllegalStateException("next must be called before remove.");
} else if (currentIndex >= map.capacity) {
map.removeStashIndex(currentIndex);
nextIndex = currentIndex - 1;
findNextIndex();
} else {
map.keyTable[currentIndex] = EMPTY;
}
currentIndex = INDEX_ILLEGAL;
map.size--;
}
}
static public class Entries extends MapIterator implements Iterable<Entry>, Iterator<Entry> {
private Entry entry = new Entry();
public Entries (IntFloatMap map) {
super(map);
}
/** Note the same entry instance is returned each time this method is called. */
public Entry next () {
if (!hasNext) throw new NoSuchElementException();
if (!valid) throw new RuntimeException("#iterator() cannot be used nested.");
int[] keyTable = map.keyTable;
if (nextIndex == INDEX_ZERO) {
entry.key = 0;
entry.value = map.zeroValue;
} else {
entry.key = keyTable[nextIndex];
entry.value = map.valueTable[nextIndex];
}
currentIndex = nextIndex;
findNextIndex();
return entry;
}
public boolean hasNext () {
if (!valid) throw new RuntimeException("#iterator() cannot be used nested.");
return hasNext;
}
public Iterator<Entry> iterator () {
return this;
}
public void remove () {
super.remove();
}
}
static public class Values extends MapIterator {
public Values (IntFloatMap map) {
super(map);
}
public boolean hasNext () {
if (!valid) throw new RuntimeException("#iterator() cannot be used nested.");
return hasNext;
}
public float next () {
if (!hasNext) throw new NoSuchElementException();
if (!valid) throw new RuntimeException("#iterator() cannot be used nested.");
float value;
if (nextIndex == INDEX_ZERO)
value = map.zeroValue;
else
value = map.valueTable[nextIndex];
currentIndex = nextIndex;
findNextIndex();
return value;
}
/** Returns a new array containing the remaining values. */
public FloatArray toArray () {
FloatArray array = new FloatArray(true, map.size);
while (hasNext)
array.add(next());
return array;
}
}
static public class Keys extends MapIterator {
public Keys (IntFloatMap map) {
super(map);
}
public boolean hasNext () {
if (!valid) throw new RuntimeException("#iterator() cannot be used nested.");
return hasNext;
}
public int next () {
if (!hasNext) throw new NoSuchElementException();
if (!valid) throw new RuntimeException("#iterator() cannot be used nested.");
int key = nextIndex == INDEX_ZERO ? 0 : map.keyTable[nextIndex];
currentIndex = nextIndex;
findNextIndex();
return key;
}
/** Returns a new array containing the remaining keys. */
public IntArray toArray () {
IntArray array = new IntArray(true, map.size);
while (hasNext)
array.add(next());
return array;
}
}
}

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/*
* Copyright 2023 dorkbox, llc
*
* 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.
*/
/*******************************************************************************
* Copyright 2011 LibGDX.
* Mario Zechner <badlogicgames></badlogicgames>@gmail.com>
* Nathan Sweet <nathan.sweet></nathan.sweet>@gmail.com>
*
* 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 dorkbox.collections
import dorkbox.collections.Collections.allocateIterators
import dorkbox.collections.ObjectSet.Companion.tableSize
import java.util.*
/**
* An unordered map where the keys are unboxed ints and values are floats. No allocation is done except when growing the table
* size.
*
* This class performs fast contains and remove (typically O(1), worst case O(n) but that is rare in practice). Add may be
* slightly slower, depending on hash collisions. Hashcodes are rehashed to reduce collisions and the need to resize. Load factors
* greater than 0.91 greatly increase the chances to resize to the next higher POT size.
*
*
* Unordered sets and maps are not designed to provide especially fast iteration. Iteration is faster with OrderedSet and
* OrderedMap.
*
*
* This implementation uses linear probing with the backward shift algorithm for removal. Hashcodes are rehashed using Fibonacci
* hashing, instead of the more common power-of-two mask, to better distribute poor hashCodes (see [Malte Skarupke's blog post](https://probablydance.com/2018/06/16/fibonacci-hashing-the-optimization-that-the-world-forgot-or-a-better-alternative-to-integer-modulo/)). Linear probing continues to work even when all hashCodes collide, just more slowly.
* @author Nathan Sweet
* @author Tommy Ettinger
*/
class IntFloatMap : MutableMap<Int, Float>, MutableIterable<IntFloatMap.Entry> {
companion object {
const val version = Collections.version
}
private var size_ = 0
var keyTable: IntArray
var valueTable: FloatArray
var zeroValue = 0F
var hasZeroValue = false
private val loadFactor: Float
private var threshold: Int
/**
* Used by [.place] to bit shift the upper bits of a `long` into a usable range (>= 0 and <=
* [.mask]). The shift can be negative, which is convenient to match the number of bits in mask: if mask is a 7-bit
* number, a shift of -7 shifts the upper 7 bits into the lowest 7 positions. This class sets the shift &gt; 32 and &lt; 64,
* which if used with an int will still move the upper bits of an int to the lower bits due to Java's implicit modulus on
* shifts.
*
* [.mask] can also be used to mask the low bits of a number, which may be faster for some hashcodes, if
* [.place] is overridden.
*/
protected var shift: Int
/**
* A bitmask used to confine hashcodes to the size of the table. Must be all 1 bits in its low positions, ie a power of two
* minus 1. If [.place] is overriden, this can be used instead of [.shift] to isolate usable bits of a
* hash.
*/
protected var mask: Int
@Transient
private var entries1: Entries? = null
@Transient
private var entries2: Entries? = null
@Transient
private var values1: Values? = null
@Transient
private var values2: Values? = null
@Transient
private var keys1: Keys? = null
@Transient
private var keys2: Keys? = null
/** Creates a new map with an initial capacity of 51 and a load factor of 0.8. */
constructor() : this(51, 0.8f)
/**
* Creates a new map with the specified initial capacity and load factor. This map will hold initialCapacity items before
* growing the backing table.
*
* @param initialCapacity The backing array size is initialCapacity / loadFactor, increased to the next power of two.
* @param loadFactor The loadfactor used to determine backing array growth
*/
constructor(initialCapacity: Int = 51, loadFactor: Float = 0.8f) {
require(!(loadFactor <= 0f || loadFactor >= 1f)) { "loadFactor must be > 0 and < 1: $loadFactor" }
this.loadFactor = loadFactor
val tableSize = tableSize(initialCapacity, loadFactor)
threshold = (tableSize * loadFactor).toInt()
mask = tableSize - 1
shift = java.lang.Long.numberOfLeadingZeros(mask.toLong())
keyTable = IntArray(tableSize)
valueTable = FloatArray(tableSize)
}
/**
* Creates a new map identical to the specified map.
*/
constructor(map: IntFloatMap) : this((map.keyTable.size * map.loadFactor).toInt(), map.loadFactor) {
System.arraycopy(map.keyTable, 0, keyTable, 0, map.keyTable.size)
System.arraycopy(map.valueTable, 0, valueTable, 0, map.valueTable.size)
size_ = map.size_
zeroValue = map.zeroValue
hasZeroValue = map.hasZeroValue
}
/**
* Returns an index >= 0 and <= [.mask] for the specified `item`.
*
* The default implementation uses Fibonacci hashing on the item's [Object.hashCode]: the hashcode is multiplied by a
* long constant (2 to the 64th, divided by the golden ratio) then the uppermost bits are shifted into the lowest positions to
* obtain an index in the desired range. Multiplication by a long may be slower than int (eg on GWT) but greatly improves
* rehashing, allowing even very poor hashcodes, such as those that only differ in their upper bits, to be used without high
* collision rates. Fibonacci hashing has increased collision rates when all or most hashcodes are multiples of larger
* Fibonacci numbers (see [Malte Skarupke's blog post](https://probablydance.com/2018/06/16/fibonacci-hashing-the-optimization-that-the-world-forgot-or-a-better-alternative-to-integer-modulo/)).
*
*
* This method can be overriden to customizing hashing. This may be useful eg in the unlikely event that most hashcodes are
* Fibonacci numbers, if keys provide poor or incorrect hashcodes, or to simplify hashing if keys provide high quality
* hashcodes and don't need Fibonacci hashing: `return item.hashCode() & mask;` */
protected fun place(item: Int): Int {
return (item * -0x61c8864680b583ebL ushr shift).toInt()
}
/**
* Returns the index of the key if already present, else -(index + 1) for the next empty index. This can be overridden in this
* pacakge to compare for equality differently than [Object.equals].
*/
private fun locateKey(key: Int): Int {
val keyTable = keyTable
var i = place(key)
while (true) {
val other = keyTable[i]
if (other == 0) return -(i + 1) // Empty space is available.
if (other == key) return i // Same key was found.
i = i + 1 and mask
}
}
override fun put(key: Int, value: Float): Float? {
if (key == 0) {
val oldValue = zeroValue
zeroValue = value
if (!hasZeroValue) {
hasZeroValue = true
size_++
}
return oldValue
}
var i = locateKey(key)
if (i >= 0) { // Existing key was found.
val oldValue = valueTable[i]
valueTable[i] = value
return oldValue
}
i = -(i + 1) // Empty space was found.
keyTable[i] = key
valueTable[i] = value
if (++size_ >= threshold) resize(keyTable.size shl 1)
return null
}
fun putAll(map: IntFloatMap) {
ensureCapacity(map.size_)
if (map.hasZeroValue) {
put(0, map.zeroValue)
}
val keyTable = map.keyTable
val valueTable = map.valueTable
var i = 0
val n = keyTable.size
while (i < n) {
val key = keyTable[i]
if (key != 0) put(key, valueTable[i])
i++
}
}
/**
* Skips checks for existing keys, doesn't increment size, doesn't need to handle key 0.
*/
private fun putResize(key: Int, value: Float) {
val keyTable = keyTable
var i = place(key)
while (true) {
if (keyTable[i] == 0) {
keyTable[i] = key
valueTable[i] = value
return
}
i = i + 1 and mask
}
}
override operator fun get(key: Int): Float? {
if (key == 0) return if (hasZeroValue) zeroValue else null
val i = locateKey(key)
return if (i >= 0) valueTable[i] else null
}
operator fun get(key: Int, defaultValue: Float?): Float? {
if (key == 0) return if (hasZeroValue) zeroValue else defaultValue
val i = locateKey(key)
return if (i >= 0) valueTable[i] else defaultValue
}
/**
* Returns the value for the removed key, or null if the key is not in the map.
*/
override fun remove(key: Int): Float? {
if (key == 0) {
if (!hasZeroValue) return null
hasZeroValue = false
val oldValue = zeroValue
zeroValue = 0F
size_--
return oldValue
}
var i = locateKey(key)
if (i < 0) return null
val keyTable = keyTable
val valueTable = valueTable
val oldValue = valueTable[i]
val mask = mask
var next = (i + 1) and mask
var k: Int
while (keyTable[next].also { k = it } != 0) {
val placement = place(k)
if ((next - placement and mask) > (i - placement and mask)) {
keyTable[i] = k
valueTable[i] = valueTable[next]
i = next
}
next = (next + 1) and mask
}
keyTable[i] = 0
valueTable[i] = 0F
size_--
return oldValue
}
/**
* Returns true if the map has one or more items.
*/
fun notEmpty(): Boolean {
return size_ > 0
}
/**
* Returns true if the map is empty.
*/
override fun isEmpty(): Boolean {
return size_ == 0
}
override fun putAll(from: Map<out Int, Float>) {
ensureCapacity(from.size)
from.entries.forEach { (k,v) ->
put(k, v)
}
}
/**
* Reduces the size of the backing arrays to be the specified capacity / loadFactor, or less. If the capacity is already less,
* nothing is done. If the map contains more items than the specified capacity, the next highest power of two capacity is used
* instead.
*/
fun shrink(maximumCapacity: Int) {
require(maximumCapacity >= 0) { "maximumCapacity must be >= 0: $maximumCapacity" }
val tableSize = tableSize(maximumCapacity, loadFactor)
if (keyTable.size > tableSize) resize(tableSize)
}
/**
* Clears the map and reduces the size of the backing arrays to be the specified capacity / loadFactor, if they are larger.
* */
fun clear(maximumCapacity: Int) {
val tableSize = tableSize(maximumCapacity, loadFactor)
if (keyTable.size <= tableSize) {
clear()
return
}
size_ = 0
hasZeroValue = false
zeroValue = 0F
resize(tableSize)
}
@Suppress("UNCHECKED_CAST")
override val entries: MutableSet<MutableMap.MutableEntry<Int, Float>>
get() = entries() as MutableSet<MutableMap.MutableEntry<Int, Float>>
override val keys: MutableSet<Int>
get() = keys()
override val size: Int
get() = size_
override val values: MutableCollection<Float>
get() = values()
override fun clear() {
if (size_ == 0) return
size_ = 0
Arrays.fill(keyTable, 0)
Arrays.fill(valueTable, 0F)
zeroValue = 0F
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.
*/
override fun containsValue(value: Float): Boolean {
val valueTable = valueTable
if (value == 0F) {
if (hasZeroValue && zeroValue == 0F) return true
val keyTable = keyTable
for (i in valueTable.indices.reversed()) if (keyTable[i] != 0 && valueTable[i] == 0F) return true
}
else {
if (value == zeroValue) return true
for (i in valueTable.indices.reversed()) if (valueTable[i] == value) return true
}
return false
}
override fun containsKey(key: Int): Boolean {
return if (key == 0) hasZeroValue else locateKey(key) >= 0
}
/**
* Returns the key for the specified value, or <tt>notFound</tt> if it is not in the map. Note this traverses the entire map
* and compares every value, which may be an expensive operation.
*/
fun findKey(value: Any?): Int? {
val valueTable = valueTable
if (value == null) {
if (hasZeroValue && zeroValue == 0F) return 0
val keyTable = keyTable
for (i in valueTable.indices.reversed()) if (keyTable[i] != 0 && valueTable[i] == 0F) return keyTable[i]
}
else {
if (value == zeroValue) return 0
for (i in valueTable.indices.reversed()) if (valueTable[i] == value) return keyTable[i]
}
return null
}
/**
* Returns the key for the specified value, or <tt>notFound</tt> if it is not in the map. Note this traverses the entire map
* and compares every value, which may be an expensive operation.
*/
fun findKey(value: Any?, notFound: Int): Int {
return findKey(value) ?: notFound
}
/**
* Increases the size of the backing array to accommodate the specified number of additional items / loadFactor. Useful before
* adding many items to avoid multiple backing array resizes.
*/
fun ensureCapacity(additionalCapacity: Int) {
val tableSize = tableSize(size_ + additionalCapacity, loadFactor)
if (keyTable.size < tableSize) resize(tableSize)
}
private fun resize(newSize: Int) {
val oldCapacity = keyTable.size
threshold = (newSize * loadFactor).toInt()
mask = newSize - 1
shift = java.lang.Long.numberOfLeadingZeros(mask.toLong())
val oldKeyTable = keyTable
val oldValueTable = valueTable
keyTable = IntArray(newSize)
valueTable = FloatArray(newSize)
if (size_ > 0) {
for (i in 0 until oldCapacity) {
val key = oldKeyTable[i]
if (key != 0) putResize(key, oldValueTable[i])
}
}
}
override fun hashCode(): Int {
var h = size_
if (hasZeroValue && zeroValue != 0F) h += zeroValue.hashCode()
val keyTable = keyTable
val valueTable = valueTable
var i = 0
val n = keyTable.size
while (i < n) {
val key = keyTable[i]
if (key != 0) {
h += key * 31
val value = valueTable[i]
if (value != 0F) {
h += value.hashCode()
}
}
i++
}
return h
}
override fun equals(other: Any?): Boolean {
if (other === this) return true
if (other !is IntFloatMap) return false
if (other.size_ != size_) return false
if (other.hasZeroValue != hasZeroValue) return false
if (hasZeroValue) {
if (other.zeroValue == 0F) {
if (zeroValue != 0F) return false
}
else {
if (other.zeroValue != zeroValue) return false
}
}
val keyTable = keyTable
val valueTable = valueTable
var i = 0
val n = keyTable.size
while (i < n) {
val key = keyTable[i]
if (key != 0) {
val value = valueTable[i]
if (value == 0F) {
if (other[key] != null) return false
}
else {
if (value != other[key]) return false
}
}
i++
}
return true
}
override fun toString(): String {
if (size_ == 0) return "[]"
val buffer = StringBuilder(32)
buffer.append('[')
val keyTable = keyTable
val valueTable = valueTable
var i = keyTable.size
if (hasZeroValue) {
buffer.append("0=")
buffer.append(zeroValue)
}
else {
while (i-- > 0) {
val key = keyTable[i]
if (key == 0) continue
buffer.append(key)
buffer.append('=')
buffer.append(valueTable[i])
break
}
}
while (i-- > 0) {
val key = keyTable[i]
if (key == 0) continue
buffer.append(", ")
buffer.append(key)
buffer.append('=')
buffer.append(valueTable[i])
}
buffer.append(']')
return buffer.toString()
}
override fun iterator(): MutableIterator<Entry> {
return entries()
}
/**
* Returns an iterator for the entries in the map. Remove is supported.
*
* If [Collections.allocateIterators] is false, the same iterator instance is returned each time this method is called.
*
* Use the [Entries] constructor for nested or multithreaded iteration.
*/
fun entries(): Entries {
if (allocateIterators) return Entries(this)
if (entries1 == null) {
entries1 = Entries(this)
entries2 = Entries(this)
}
if (!entries1!!.valid) {
entries1!!.reset()
entries1!!.valid = true
entries2!!.valid = false
return entries1!!
}
entries2!!.reset()
entries2!!.valid = true
entries1!!.valid = false
return entries2!!
}
/**
* Returns an iterator for the values in the map. Remove is supported.
*
* If [Collections.allocateIterators] is false, the same iterator instance is returned each time this method is called.
* Use the [Entries] constructor for nested or multithreaded iteration.
*/
fun values(): Values {
if (allocateIterators) return Values(this)
if (values1 == null) {
values1 = Values(this)
values2 = Values(this)
}
if (!values1!!.valid) {
values1!!.reset()
values1!!.valid = true
values2!!.valid = false
return values1!!
}
values2!!.reset()
values2!!.valid = true
values1!!.valid = false
return values2!!
}
/**
* Returns an iterator for the keys in the map. Remove is supported.
*
* If [Collections.allocateIterators] is false, the same iterator instance is returned each time this method is called.
* Use the [Entries] constructor for nested or multithreaded iteration.
*/
fun keys(): Keys {
if (allocateIterators) return Keys(this)
if (keys1 == null) {
keys1 = Keys(this)
keys2 = Keys(this)
}
if (!keys1!!.valid) {
keys1!!.reset()
keys1!!.valid = true
keys2!!.valid = false
return keys1!!
}
keys2!!.reset()
keys2!!.valid = true
keys1!!.valid = false
return keys2!!
}
class Entry: MutableMap.MutableEntry<Int, Float> {
override var key = 0
override var value = 0F
override fun setValue(newValue: Float): Float {
val oldValue = value
value = newValue
return oldValue
}
override fun toString(): String {
return "$key=$value"
}
}
abstract class MapIterator<V, I>(map: IntFloatMap): Iterable<I>, MutableIterator<I> {
var hasNext = false
val map: IntFloatMap
var nextIndex = 0
var currentIndex = 0
var valid = true
init {
this.map = map
reset()
}
fun reset() {
currentIndex = INDEX_ILLEGAL
nextIndex = INDEX_ZERO
if (map.hasZeroValue) hasNext = true else findNextIndex()
}
fun findNextIndex() {
val keyTable = map.keyTable
val n = keyTable.size
while (++nextIndex < n) {
if (keyTable[nextIndex] != 0) {
hasNext = true
return
}
}
hasNext = false
}
override fun remove() {
var i = currentIndex
if (i == INDEX_ZERO && map.hasZeroValue) {
map.hasZeroValue = false
map.zeroValue = 0F
} else if (i < 0) {
throw IllegalStateException("next must be called before remove.");
} else {
val keyTable = map.keyTable
val valueTable = map.valueTable
val mask = map.mask
var next = (i + 1) and mask
var key: Int
while (keyTable[next].also { key = it } != 0) {
val placement = map.place(key)
if ((next - placement and mask) > (i - placement and mask)) {
keyTable[i] = key
valueTable[i] = valueTable[next]
i = next
}
next = (next + 1) and mask
}
keyTable[i] = 0
valueTable[i] = 0F
if (i != currentIndex) --nextIndex
currentIndex = INDEX_ILLEGAL
map.size_--
}
}
companion object {
private const val INDEX_ILLEGAL = -2
const val INDEX_ZERO = -1
}
}
class Entries(map: IntFloatMap) : MutableSet<Entry>, MapIterator<Int, Entry>(map) {
private val entry = Entry()
/** Note the same entry instance is returned each time this method is called. */
override fun next(): Entry {
if (!hasNext) throw NoSuchElementException()
if (!valid) throw RuntimeException("#iterator() cannot be used nested.")
val keyTable = map.keyTable
if (nextIndex == INDEX_ZERO) {
entry.key = 0
entry.value = map.zeroValue
}
else {
entry.key = keyTable[nextIndex]
entry.value = map.valueTable[nextIndex]
}
currentIndex = nextIndex
findNextIndex()
return entry
}
override fun hasNext(): Boolean {
if (!valid) throw RuntimeException("#iterator() cannot be used nested.")
return hasNext
}
override fun add(element: Entry): Boolean {
map.put(element.key, element.value)
return true
}
override fun addAll(elements: Collection<Entry>): Boolean {
var added = false
elements.forEach {
map.put(it.key, it.value)
added = true
}
return added
}
override val size: Int
get() = map.size_
override fun clear() {
map.clear()
reset()
}
override fun isEmpty(): Boolean {
return map.isEmpty()
}
override fun containsAll(elements: Collection<Entry>): Boolean {
elements.forEach {(k,v) ->
if (map.get(k) != v) {
return false
}
}
return true
}
override fun contains(element: Entry): Boolean {
return (map.get(element.key) == element.value)
}
override fun iterator(): MutableIterator<Entry> {
return this
}
override fun retainAll(elements: Collection<Entry>): Boolean {
var removed = false
// check zero value first
if (map.hasZeroValue) {
val hasElement = elements.firstOrNull { it.key == 0 } != null
if (hasElement) {
removed = map.remove(0) != null
}
}
// now check remaining entries
map.keyTable.forEach { key ->
if (key == 0) return@forEach
val hasElement = elements.firstOrNull { it.key == key } != null
if (!hasElement) {
removed = map.remove(key) != null || removed
}
}
reset()
return removed
}
override fun removeAll(elements: Collection<Entry>): Boolean {
var removed = false
elements.forEach { (k,_) ->
removed = map.remove(k) != null || removed
}
reset()
return removed
}
override fun remove(element: Entry): Boolean {
val removed = map.remove(entry.key) != null
reset()
return removed
}
}
class Values(map: IntFloatMap) : MutableCollection<Float>, MapIterator<Int, Float>(map) {
override fun hasNext(): Boolean {
if (!valid) throw RuntimeException("#iterator() cannot be used nested.")
return hasNext
}
override fun next(): Float {
if (!hasNext) throw NoSuchElementException()
if (!valid) throw RuntimeException("#iterator() cannot be used nested.")
val value = if (nextIndex == INDEX_ZERO) {
map.zeroValue
} else {
map.valueTable[nextIndex]
}
currentIndex = nextIndex
findNextIndex()
return value
}
override val size: Int
get() = map.size_
override fun clear() {
map.clear()
reset()
}
override fun addAll(elements: Collection<Float>): Boolean {
throw IllegalStateException("Cannot add values to a map without keys")
}
override fun add(element: Float): Boolean {
throw IllegalStateException("Cannot add values to a map without keys")
}
override fun isEmpty(): Boolean {
return map.isEmpty()
}
override fun containsAll(elements: Collection<Float>): Boolean {
elements.forEach {
if (!map.containsValue(it)) {
return false
}
}
return true
}
override fun contains(element: Float): Boolean {
return map.containsValue(element)
}
override fun iterator(): MutableIterator<Float> {
return this
}
override fun retainAll(elements: Collection<Float>): Boolean {
var removed = false
map.keyTable.forEach { key ->
if (key != 0) {
val value = map[key]
if (!elements.contains(value)) {
map.remove(key)
removed = true
}
}
}
reset()
return removed
}
override fun removeAll(elements: Collection<Float>): Boolean {
var removed = false
elements.forEach {
val key = map.findKey(it)
if (key != null) {
removed = map.remove(key) != null || removed
}
}
reset()
return removed
}
override fun remove(element: Float): Boolean {
var removed = false
val key = map.findKey(element)
if (key != null) {
removed = map.remove(key) != null
}
reset()
return removed
}
/**
* Returns a new array containing the remaining values.
*/
fun toArray(): FloatArray {
val array = FloatArray(map.size)
var index = 0
while (hasNext()) {
array[index++] = next()
}
return array
}
}
class Keys(map: IntFloatMap) : MutableSet<Int>, MapIterator<Int, Int>(map) {
override fun hasNext(): Boolean {
if (!valid) throw RuntimeException("#iterator() cannot be used nested.")
return hasNext
}
override operator fun next(): Int {
if (!hasNext) throw NoSuchElementException()
if (!valid) throw RuntimeException("#iterator() cannot be used nested.")
val key = if (nextIndex == INDEX_ZERO) 0 else map.keyTable[nextIndex]
currentIndex = nextIndex
findNextIndex()
return key
}
override val size: Int
get() = map.size_
override fun clear() {
map.clear()
}
override fun addAll(elements: Collection<Int>): Boolean {
var alreadyAdded = false
elements.forEach {
alreadyAdded = alreadyAdded || map.put(it, 0F) == null
}
return alreadyAdded
}
override fun add(element: Int): Boolean {
return map.put(element, 0F) == null
}
override fun isEmpty(): Boolean {
return map.size_ == 0
}
override fun containsAll(elements: Collection<Int>): Boolean {
elements.forEach {
if (!map.containsKey(it)) {
return false
}
}
return true
}
override fun contains(element: Int): Boolean {
return map.containsKey(element)
}
override fun iterator(): MutableIterator<Int> {
return this
}
override fun retainAll(elements: Collection<Int>): Boolean {
var removed = false
map.keyTable.forEach {
if (!elements.contains(it)) {
if (map.remove(it) == null) {
removed = true
}
}
}
reset()
return removed
}
override fun removeAll(elements: Collection<Int>): Boolean {
var removed = false
elements.forEach {
if (map.remove(it) == null) {
removed = true
}
}
reset()
return removed
}
override fun remove(element: Int): Boolean {
return map.remove(element) == null
}
/**
* Returns a new array containing the remaining keys.
*/
fun toArray(): IntArray {
val array = IntArray(map.size)
var index = 0
while (hasNext()) {
array[index++] = next()
}
return array
}
/**
* Adds the remaining values to the specified array.
*/
fun toArray(array: IntArray): IntArray {
var index = 0
while (hasNext) {
array[index++] = next()
}
return array
}
}
}