org.eclipse.jdt.internal.compiler.util.HashtableOfObjectToInt 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 of {Object --> int }
*/
public final class HashtableOfObjectToInt implements Cloneable {
// to avoid using Enumerations, walk the individual tables skipping nulls
public Object[] keyTable;
public int[] valueTable;
public int elementSize; // number of elements in the table
int threshold;
public HashtableOfObjectToInt() {
this(13);
}
public HashtableOfObjectToInt(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 Object[extraRoom];
this.valueTable = new int[extraRoom];
}
public Object clone() throws CloneNotSupportedException {
HashtableOfObjectToInt result = (HashtableOfObjectToInt) super.clone();
result.elementSize = this.elementSize;
result.threshold = this.threshold;
int length = this.keyTable.length;
result.keyTable = new Object[length];
System.arraycopy(this.keyTable, 0, result.keyTable, 0, length);
length = this.valueTable.length;
result.valueTable = new int[length];
System.arraycopy(this.valueTable, 0, result.valueTable, 0, length);
return result;
}
public boolean containsKey(Object key) {
int length = this.keyTable.length,
index = (key.hashCode()& 0x7FFFFFFF) % length;
Object currentKey;
while ((currentKey = this.keyTable[index]) != null) {
if (currentKey.equals(key))
return true;
if (++index == length) {
index = 0;
}
}
return false;
}
public int get(Object key) {
int length = this.keyTable.length,
index = (key.hashCode()& 0x7FFFFFFF) % length;
Object currentKey;
while ((currentKey = this.keyTable[index]) != null) {
if (currentKey.equals(key))
return this.valueTable[index];
if (++index == length) {
index = 0;
}
}
return -1;
}
public void keysToArray(Object[] array) {
int index = 0;
for (int i=0, length=this.keyTable.length; i this.threshold)
rehash();
return value;
}
public int removeKey(Object key) {
int length = this.keyTable.length,
index = (key.hashCode()& 0x7FFFFFFF) % length;
Object currentKey;
while ((currentKey = this.keyTable[index]) != null) {
if (currentKey.equals(key)) {
int value = this.valueTable[index];
this.elementSize--;
this.keyTable[index] = null;
rehash();
return value;
}
if (++index == length) {
index = 0;
}
}
return -1;
}
private void rehash() {
HashtableOfObjectToInt newHashtable = new HashtableOfObjectToInt(this.elementSize * 2); // double the number of expected elements
Object currentKey;
for (int i = this.keyTable.length; --i >= 0;)
if ((currentKey = this.keyTable[i]) != null)
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 key;
for (int i = 0, length = this.keyTable.length; i < length; i++)
if ((key = this.keyTable[i]) != null)
s += key + " -> " + this.valueTable[i] + "\n"; //$NON-NLS-2$ //$NON-NLS-1$
return s;
}
}