2 * Copyright (C) 2014, United States Government, as represented by the
3 * Administrator of the National Aeronautics and Space Administration.
6 * The Java Pathfinder core (jpf-core) platform is licensed under the
7 * Apache License, Version 2.0 (the "License"); you may not use this file except
8 * in compliance with the License. You may obtain a copy of the License at
10 * http://www.apache.org/licenses/LICENSE-2.0.
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
18 package gov.nasa.jpf.util;
20 import java.util.ArrayList;
24 * data structure used to do hash collapsing. All the major state components
25 * (fields, Monitors, StackFrames, uThreadData) are stored in pools to
26 * determine if they are new. Only the pool index values are used to
27 * compute hash values.
29 * 2006-06-14 - major rewrite by pcd
31 public final class HashPool<V> {
32 private IntTable<V> pool;
33 private ArrayList<V> vect;
36 this(8); // default to 256 slots
39 public HashPool(int pow) {
40 pool = new IntTable<V>(pow);
41 vect = new ArrayList<V>(1 << pow);
44 /** optionally called only once after creation to link null to 0. */
45 public HashPool<V> addNull() {
51 throw new IllegalStateException();
55 public IntTable.Entry<V> getEntry (V o) {
56 int sz = pool.size(); // == vect.size();
58 IntTable.Entry<V> e = pool.pool(o);
65 public int getIndex (V o) {
66 return getEntry(o).val;
70 return getEntry(o).key;
73 public V getObject (int idx) {
77 public void print () {
78 System.out.println("{");
80 for (IntTable.Entry<V> entry : pool) {
81 System.out.println("\t" + entry);
84 System.out.println("}");