/*******************************************************************************
* Copyright (c) 2002 - 2006 IBM Corporation.
* 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 com.ibm.wala.util.collections;
import java.util.ArrayList;
import java.util.Iterator;
/**
* simple implementation of IVector
*/
public class SimpleVector<T> implements IVector<T> {
private final static int MAX_SIZE = Integer.MAX_VALUE / 4;
private final static double GROWTH_FACTOR = 1.5;
Object[] store = new Object[1];
int maxIndex = -1;
public SimpleVector() {
}
/*
* @see com.ibm.wala.util.intset.IntVector#get(int)
*/
@Override
@SuppressWarnings("unchecked")
public T get(int x) {
if (x < 0) {
throw new IllegalArgumentException("illegal x: " + x);
}
if (x < store.length) {
return (T) store[x];
} else {
return null;
}
}
/*
* @see com.ibm.wala.util.intset.IVector#set(int, int)
*/
@Override
public void set(int x, T value) {
if (x < 0) {
throw new IllegalArgumentException("illegal x value " + x);
}
if (x > MAX_SIZE) {
throw new IllegalArgumentException("x is too big: " + x);
}
maxIndex = Math.max(maxIndex,x);
if (value == null) {
if (x >= store.length) {
return;
} else {
store[x] = null;
}
} else {
ensureCapacity(x);
store[x] = value;
}
}
/**
* make sure we can store to a particular index
*/
private void ensureCapacity(int capacity) {
if (capacity >= store.length) {
Object[] old = store;
store = new Object[1 + (int) (GROWTH_FACTOR * capacity)];
System.arraycopy(old, 0, store, 0, old.length);
}
}
/*
* @see com.ibm.wala.util.intset.IntVector#reportStats()
*/
@Override
public void performVerboseAction() {
System.err.println(("size: " + store.length));
System.err.println(("occupancy: " + computeOccupancy()));
}
/**
* @return the percentage of entries in delegateStore that are non-null
*/
private double computeOccupancy() {
int count = 0;
for (int i = 0; i < store.length; i++) {
if (store[i] != null) {
count++;
}
}
return (double) count / (double) store.length;
}
@Override
@SuppressWarnings("unchecked")
public Iterator<T> iterator() {
ArrayList<T> result = new ArrayList<T>();
for (int i =0; i <= maxIndex; i++) {
result.add((T) store[i]);
}
return result.iterator();
}
@Override
public int getMaxIndex() {
return maxIndex;
}
}