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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.builder;
public class StringSet {
// to avoid using Enumerations, walk the individual values skipping nulls
public String[] values;
public int elementSize; // number of elements in the table
public int threshold;
public StringSet(int size) {
this.elementSize = 0;
this.threshold = size; // size represents the expected number of elements
int extraRoom = (int) (size * 1.5f);
if (this.threshold == extraRoom)
extraRoom++;
this.values = new String[extraRoom];
}
public boolean add(String value) {
int length = this.values.length;
int index = (value.hashCode() & 0x7FFFFFFF) % length;
String current;
while ((current = this.values[index]) != null) {
if (value.equals(current)) return false; // did not add it since it already existed
if (++index == length) index = 0;
}
this.values[index] = value;
// assumes the threshold is never equal to the size of the table
if (++this.elementSize > this.threshold) rehash();
return true;
}
public void clear() {
for (int i = this.values.length; --i >= 0;)
this.values[i] = null;
this.elementSize = 0;
}
public boolean includes(String value) {
int length = this.values.length;
int index = (value.hashCode() & 0x7FFFFFFF) % length;
String current;
while ((current = this.values[index]) != null) {
if (value.equals(current)) return true;
if (++index == length) index = 0;
}
return false;
}
private void rehash() {
StringSet newSet = new StringSet(this.elementSize * 2); // double the number of expected elements
String current;
for (int i = this.values.length; --i >= 0;)
if ((current = this.values[i]) != null)
newSet.add(current);
this.values = newSet.values;
this.elementSize = newSet.elementSize;
this.threshold = newSet.threshold;
}
@Override
public String toString() {
String s = ""; //$NON-NLS-1$
String value;
for (int i = 0, l = this.values.length; i < l; i++)
if ((value = this.values[i]) != null)
s += value + "\n"; //$NON-NLS-1$
return s;
}
}