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/*******************************************************************************
* Copyright 2011 LibGDX.
* Mario Zechner
* Nathan Sweet
*
* 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.util.collections;
import java.util.Iterator;
import java.util.NoSuchElementException;
import dorkbox.util.MathUtil;
import dorkbox.util.RandomUtil;
/** 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.
*
* 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 {
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 = MathUtil.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 (RandomUtil.int_(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 = MathUtil.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(MathUtil.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 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, Iterator {
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 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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