java.util.HugeEnumSet Maven / Gradle / Ivy
/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 java.util;
/**
* A concrete EnumSet for enums with more than 64 elements.
*/
@SuppressWarnings("serial")
final class HugeEnumSet> extends EnumSet {
private static final int BIT_IN_LONG = 64;
final private E[] enums;
private long[] bits;
private int size;
/**
* Constructs an instance.
*
* @param elementType non-null; type of the elements
* @param enums non-null; pre-populated array of constants in ordinal
* order
*/
HugeEnumSet(Class elementType, E[] enums) {
super(elementType);
this.enums = enums;
bits = new long[(enums.length + BIT_IN_LONG - 1) / BIT_IN_LONG];
}
private class HugeEnumSetIterator implements Iterator {
/**
* The bits yet to be returned for the long in bits[index]. As values from the current index
* are returned, their bits are zeroed out. When this reaches zero, the index must be
* incremented.
*/
private long currentBits = bits[0];
/**
* The index into HugeEnumSet.bits of the next value to return.
*/
private int index;
/**
* The single bit of the next value to return.
*/
private long mask;
/**
* The candidate for removal. If null, no value may be removed.
*/
private E last;
private HugeEnumSetIterator() {
computeNextElement();
}
/**
* Assigns mask and index to the next available value, cycling currentBits as necessary.
*/
void computeNextElement() {
while (true) {
if (currentBits != 0) {
mask = currentBits & -currentBits; // the lowest 1 bit in currentBits
return;
} else if (++index < bits.length) {
currentBits = bits[index];
} else {
mask = 0;
return;
}
}
}
public boolean hasNext() {
return mask != 0;
}
public E next() {
if (mask == 0) {
throw new NoSuchElementException();
}
int ordinal = Long.numberOfTrailingZeros(mask) + index * BIT_IN_LONG;
last = enums[ordinal];
currentBits &= ~mask;
computeNextElement();
return last;
}
public void remove() {
if (last == null) {
throw new IllegalStateException();
}
HugeEnumSet.this.remove(last);
last = null;
}
}
@Override
public boolean add(E element) {
elementClass.cast(element); // Called to throw ClassCastException.
int ordinal = element.ordinal();
int index = ordinal / BIT_IN_LONG;
int inBits = ordinal % BIT_IN_LONG;
long oldBits = bits[index];
long newBits = oldBits | (1L << inBits);
if (oldBits != newBits) {
bits[index] = newBits;
size++;
return true;
}
return false;
}
@Override
public boolean addAll(Collection collection) {
if (collection.isEmpty() || collection == this) {
return false;
}
if (collection instanceof EnumSet) {
EnumSet set = (EnumSet) collection; // raw type due to javac bug 6548436
set.elementClass.asSubclass(elementClass); // Called to throw ClassCastException.
HugeEnumSet hugeSet = (HugeEnumSet) set;
boolean changed = false;
for (int i = 0; i < bits.length; i++) {
long oldBits = bits[i];
long newBits = oldBits | hugeSet.bits[i];
if (oldBits != newBits) {
bits[i] = newBits;
size += Long.bitCount(newBits) - Long.bitCount(oldBits);
changed = true;
}
}
return changed;
}
return super.addAll(collection);
}
@Override
public int size() {
return size;
}
@Override
public void clear() {
Arrays.fill(bits, 0);
size = 0;
}
@Override
protected void complement() {
size = 0;
for (int i = 0, length = bits.length; i < length; i++) {
long b = ~bits[i];
// zero out unused bits on the last element
if (i == length - 1) {
b &= -1L >>> (BIT_IN_LONG - (enums.length % BIT_IN_LONG));
}
size += Long.bitCount(b);
bits[i] = b;
}
}
@Override
public boolean contains(Object object) {
if (object == null || !isValidType(object.getClass())) {
return false;
}
@SuppressWarnings("unchecked") // guarded by isValidType()
int ordinal = ((E) object).ordinal();
int index = ordinal / BIT_IN_LONG;
int inBits = ordinal % BIT_IN_LONG;
return (bits[index] & (1L << inBits)) != 0;
}
@Override
public HugeEnumSet clone() {
HugeEnumSet set = (HugeEnumSet) super.clone();
set.bits = bits.clone();
return set;
}
@Override
public boolean containsAll(Collection collection) {
if (collection.isEmpty()) {
return true;
}
if (collection instanceof HugeEnumSet) {
HugeEnumSet set = (HugeEnumSet) collection;
if (isValidType(set.elementClass)) {
for (int i = 0; i < bits.length; i++) {
long setBits = set.bits[i];
if ((bits[i] & setBits) != setBits) {
return false;
}
}
return true;
}
}
return !(collection instanceof EnumSet) && super.containsAll(collection);
}
@Override
public boolean equals(Object object) {
if (object == null) {
return false;
}
if (!isValidType(object.getClass())) {
return super.equals(object);
}
return Arrays.equals(bits, ((HugeEnumSet) object).bits);
}
@Override
public Iterator iterator() {
return new HugeEnumSetIterator();
}
@Override
public boolean remove(Object object) {
if (object == null || !isValidType(object.getClass())) {
return false;
}
@SuppressWarnings("unchecked") // guarded by isValidType()
int ordinal = ((E) object).ordinal();
int index = ordinal / BIT_IN_LONG;
int inBits = ordinal % BIT_IN_LONG;
long oldBits = bits[index];
long newBits = oldBits & ~(1L << inBits);
if (oldBits != newBits) {
bits[index] = newBits;
size--;
return true;
}
return false;
}
@Override
public boolean removeAll(Collection collection) {
if (collection.isEmpty()) {
return false;
}
if (collection instanceof EnumSet) {
EnumSet set = (EnumSet) collection;
if (!isValidType(set.elementClass)) {
return false;
}
HugeEnumSet hugeSet = (HugeEnumSet) set;
boolean changed = false;
for (int i = 0; i < bits.length; i++) {
long oldBits = bits[i];
long newBits = oldBits & ~hugeSet.bits[i];
if (oldBits != newBits) {
bits[i] = newBits;
size += Long.bitCount(newBits) - Long.bitCount(oldBits);
changed = true;
}
}
return changed;
}
return super.removeAll(collection);
}
@Override
public boolean retainAll(Collection collection) {
if (collection instanceof EnumSet) {
EnumSet set = (EnumSet) collection;
if (!isValidType(set.elementClass)) {
if (size > 0) {
clear();
return true;
} else {
return false;
}
}
HugeEnumSet hugeSet = (HugeEnumSet) set;
boolean changed = false;
for (int i = 0; i < bits.length; i++) {
long oldBits = bits[i];
long newBits = oldBits & hugeSet.bits[i];
if (oldBits != newBits) {
bits[i] = newBits;
size += Long.bitCount(newBits) - Long.bitCount(oldBits);
changed = true;
}
}
return changed;
}
return super.retainAll(collection);
}
@Override
void setRange(E start, E end) {
int startOrdinal = start.ordinal();
int startIndex = startOrdinal / BIT_IN_LONG;
int startInBits = startOrdinal % BIT_IN_LONG;
int endOrdinal = end.ordinal();
int endIndex = endOrdinal / BIT_IN_LONG;
int endInBits = endOrdinal % BIT_IN_LONG;
if (startIndex == endIndex) {
long range = (-1L >>> (BIT_IN_LONG -(endInBits - startInBits + 1))) << startInBits;
size -= Long.bitCount(bits[startIndex]);
bits[startIndex] |= range;
size += Long.bitCount(bits[startIndex]);
} else {
long range = (-1L >>> startInBits) << startInBits;
size -= Long.bitCount(bits[startIndex]);
bits[startIndex] |= range;
size += Long.bitCount(bits[startIndex]);
// endInBits + 1 is the number of consecutive ones.
// 63 - endInBits is the following zeros of the right most one.
range = -1L >>> (BIT_IN_LONG - (endInBits + 1));
size -= Long.bitCount(bits[endIndex]);
bits[endIndex] |= range;
size += Long.bitCount(bits[endIndex]);
for (int i = (startIndex + 1); i <= (endIndex - 1); i++) {
size -= Long.bitCount(bits[i]);
bits[i] = -1L;
size += Long.bitCount(bits[i]);
}
}
}
}