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/*******************************************************************************
* Copyright (c) 2000, 2009 IBM Corporation and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.internal.core.util;
/**
* HashSet of Object[]
*/
public final class HashSetOfArray implements Cloneable {
// to avoid using Enumerations, walk the individual tables skipping nulls
public Object[][] set;
public int elementSize; // number of elements in the table
int threshold;
public HashSetOfArray() {
this(13);
}
public HashSetOfArray(int size) {
this.elementSize = 0;
this.threshold = size; // size represents the expected number of elements
int extraRoom = (int) (size * 1.75f);
if (this.threshold == extraRoom)
extraRoom++;
this.set = new Object[extraRoom][];
}
@Override
public Object clone() throws CloneNotSupportedException {
HashSetOfArray result = (HashSetOfArray) super.clone();
result.elementSize = this.elementSize;
result.threshold = this.threshold;
int length = this.set.length;
result.set = new Object[length][];
System.arraycopy(this.set, 0, result.set, 0, length);
return result;
}
public boolean contains(Object[] array) {
int length = this.set.length;
int index = hashCode(array) % length;
int arrayLength = array.length;
Object[] currentArray;
while ((currentArray = this.set[index]) != null) {
if (currentArray.length == arrayLength && Util.equalArraysOrNull(currentArray, array))
return true;
if (++index == length) {
index = 0;
}
}
return false;
}
private int hashCode(Object[] element) {
return hashCode(element, element.length);
}
private int hashCode(Object[] element, int length) {
int hash = 0;
for (int i = length-1; i >= 0; i--)
hash = Util.combineHashCodes(hash, element[i].hashCode());
return hash & 0x7FFFFFFF;
}
public Object add(Object[] array) {
int length = this.set.length;
int index = hashCode(array) % length;
int arrayLength = array.length;
Object[] currentArray;
while ((currentArray = this.set[index]) != null) {
if (currentArray.length == arrayLength && Util.equalArraysOrNull(currentArray, array))
return this.set[index] = array;
if (++index == length) {
index = 0;
}
}
this.set[index] = array;
// assumes the threshold is never equal to the size of the table
if (++this.elementSize > this.threshold)
rehash();
return array;
}
public Object remove(Object[] array) {
int length = this.set.length;
int index = hashCode(array) % length;
int arrayLength = array.length;
Object[] currentArray;
while ((currentArray = this.set[index]) != null) {
if (currentArray.length == arrayLength && Util.equalArraysOrNull(currentArray, array)) {
Object existing = this.set[index];
this.elementSize--;
this.set[index] = null;
rehash();
return existing;
}
if (++index == length) {
index = 0;
}
}
return null;
}
private void rehash() {
HashSetOfArray newHashSet = new HashSetOfArray(this.elementSize * 2); // double the number of expected elements
Object[] currentArray;
for (int i = this.set.length; --i >= 0;)
if ((currentArray = this.set[i]) != null)
newHashSet.add(currentArray);
this.set = newHashSet.set;
this.threshold = newHashSet.threshold;
}
public int size() {
return this.elementSize;
}
@Override
public String toString() {
StringBuilder buffer = new StringBuilder();
Object[] element;
for (int i = 0, length = this.set.length; i < length; i++)
if ((element = this.set[i]) != null) {
buffer.append('{');
for (int j = 0, length2 = element.length; j < length2; j++) {
buffer.append(element[j]);
if (j != length2-1)
buffer.append(", "); //$NON-NLS-1$
}
buffer.append("}"); //$NON-NLS-1$
if (i != length-1)
buffer.append('\n');
}
return buffer.toString();
}
}