Mercurial > hg > Members > kono > jpf-core
view src/main/gov/nasa/jpf/util/ArrayIntSet.java @ 0:61d41facf527
initial v8 import (history reset)
author | Peter Mehlitz <Peter.C.Mehlitz@nasa.gov> |
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date | Fri, 23 Jan 2015 10:14:01 -0800 |
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/* * Copyright (C) 2014, United States Government, as represented by the * Administrator of the National Aeronautics and Space Administration. * All rights reserved. * * The Java Pathfinder core (jpf-core) platform is licensed under the * Apache License, Version 2.0 (the "License"); you may not use this file except * in compliance with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0. * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package gov.nasa.jpf.util; import java.util.NoSuchElementException; import gov.nasa.jpf.JPFException; /** * common base for array based IntSet implementations */ public abstract class ArrayIntSet implements IntSet, Cloneable { protected int size; protected int[] elements; private class Iterator implements IntIterator { int next = 0; @Override public void remove() { int idx = next-1; if (idx >=0){ if (idx < size-1){ System.arraycopy(elements, next, elements, idx, size-idx); } size--; next = idx; } } @Override public boolean hasNext() { return (next < size); } @Override public int next() { if (next < size){ return elements[next++]; } else { throw new NoSuchElementException(); } } } protected ArrayIntSet (){ // nothing } protected ArrayIntSet (int initialCapacity){ elements = new int[initialCapacity]; } @Override public boolean isEmpty(){ return (size == 0); } @Override public int size(){ return size; } @Override public void clear(){ size = 0; elements = null; } @Override public String toString(){ StringBuilder sb = new StringBuilder(/*getClass().getName()*/); sb.append('{'); for (int i=0; i<size; i++){ if (i>0){ sb.append(','); } sb.append(elements[i]); } sb.append('}'); return sb.toString(); } @Override public ArrayIntSet clone(){ try { ArrayIntSet other = (ArrayIntSet) super.clone(); other.size = size; if (elements != null) { other.elements = elements.clone(); } return other; } catch (CloneNotSupportedException cnsx){ throw new JPFException("clone failed " + this); } } /** * this is probably a bad hash function, but we just need something that * is order independent */ @Override public int hashCode(){ int[] a = elements; int n = size; int h = (n << 16) + (n % 3); for (int i = 0; i < n; i++) { int e = a[i]; if (e == 0){ e = Integer.MAX_VALUE; } int rot = e % 31; h ^= (h << rot) | (h >>> (32 - rot)); // rotate left } return h; } @Override public boolean equals (Object o){ if (o instanceof IntSet){ IntSet other = (IntSet)o; if (size == other.size()){ int len = size; int[] a = elements; for (int i=0; i<len; i++){ if (!other.contains(a[i])){ return false; } } return true; } } return false; } @Override public IntIterator intIterator (){ return new Iterator(); } }