//
// Copyright (C) 2012 United States Government as represented by the
// Administrator of the National Aeronautics and Space Administration
// (NASA). All Rights Reserved.
//
// This software is distributed under the NASA Open Source Agreement
// (NOSA), version 1.3. The NOSA has been approved by the Open Source
// Initiative. See the file NOSA-1.3-JPF at the top of the distribution
// directory tree for the complete NOSA document.
//
// THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
// KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
// LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
// SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
// A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
// THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
// DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
//
package gov.nasa.jpf.util;
/**
* a simplistic IntSet implementation that uses an unsorted array to keep elements.
* Obviously this is O(N) and therefore not a good choice if the list grows,
* but if we know there are only a few elements then it isn't worth to
* do any sorting or fancy lookup - the JIT would beat algorithm.
*
* If the set is empty there is no memory allocated for the elements
*/
public class UnsortedArrayIntSet extends ArrayIntSet {
static final int DEFAULT_CAPACITY = 4;
static final int GROWTH = 8;
public UnsortedArrayIntSet (){
// nothing
}
public UnsortedArrayIntSet (int initialCapacity){
super(initialCapacity);
}
@Override
public boolean add (int v) {
int len = size;
if (len == 0){
elements = new int[DEFAULT_CAPACITY];
} else {
int[] a = elements;
int i=0;
for (; i<len; i++){
if (a[i] == v){
return false; // was already there
}
}
if (i == a.length){
int[] newElements = new int[a.length + GROWTH];
System.arraycopy(a, 0, newElements, 0, size);
elements = newElements;
}
}
elements[size++] = v;
return true;
}
@Override
public boolean remove(int v) {
int len = size;
if (len > 0){
int[] a = elements;
for (int i=0; i<len; i++){
if (a[i] == v){
if (len == 1){
elements = null;
} else {
i++;
if (i < len) {
System.arraycopy(a, i, a, i-1, len-i);
}
}
size--;
return true;
}
}
}
return false; // wasn't there
}
@Override
public boolean contains(int v) {
int len = size;
if (len > 0){
int[] a = elements;
for (int i=0; i<len; i++){
if (a[i] == v){
return true;
}
}
}
return false;
}
}