org.eclipse.jdt.internal.compiler.util.HashtableOfInt Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2000, 2009 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.internal.compiler.util;
/**
* Hashtable for non-zero int keys.
*/
public final class HashtableOfInt {
// to avoid using Enumerations, walk the individual tables skipping nulls
public int[] keyTable;
public Object[] valueTable;
public int elementSize; // number of elements in the table
int threshold;
public HashtableOfInt() {
this(13);
}
public HashtableOfInt(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.keyTable = new int[extraRoom];
this.valueTable = new Object[extraRoom];
}
public boolean containsKey(int key) {
int length = this.keyTable.length, index = key % length;
int currentKey;
while ((currentKey = this.keyTable[index]) != 0) {
if (currentKey == key)
return true;
if (++index == length) {
index = 0;
}
}
return false;
}
public Object get(int key) {
int length = this.keyTable.length, index = key % length;
int currentKey;
while ((currentKey = this.keyTable[index]) != 0) {
if (currentKey == key) return this.valueTable[index];
if (++index == length) {
index = 0;
}
}
return null;
}
public Object put(int key, Object value) {
int length = this.keyTable.length, index = key % length;
int currentKey;
while ((currentKey = this.keyTable[index]) != 0) {
if (currentKey == key) return this.valueTable[index] = value;
if (++index == length) {
index = 0;
}
}
this.keyTable[index] = key;
this.valueTable[index] = value;
// assumes the threshold is never equal to the size of the table
if (++this.elementSize > this.threshold)
rehash();
return value;
}
private void rehash() {
HashtableOfInt newHashtable = new HashtableOfInt(this.elementSize * 2); // double the number of expected elements
int currentKey;
for (int i = this.keyTable.length; --i >= 0;)
if ((currentKey = this.keyTable[i]) != 0)
newHashtable.put(currentKey, this.valueTable[i]);
this.keyTable = newHashtable.keyTable;
this.valueTable = newHashtable.valueTable;
this.threshold = newHashtable.threshold;
}
public int size() {
return this.elementSize;
}
public String toString() {
String s = ""; //$NON-NLS-1$
Object object;
for (int i = 0, length = this.valueTable.length; i < length; i++)
if ((object = this.valueTable[i]) != null)
s += this.keyTable[i] + " -> " + object.toString() + "\n"; //$NON-NLS-2$ //$NON-NLS-1$
return s;
}
}