1 /******************************************************************************* 2 * Copyright (c) 2000, 2008 IBM Corporation and others. 3 * 4 * This program and the accompanying materials 5 * are made available under the terms of the Eclipse Public License 2.0 6 * which accompanies this distribution, and is available at 7 * https://www.eclipse.org/legal/epl-2.0/ 8 * 9 * SPDX-License-Identifier: EPL-2.0 10 * 11 * Contributors: 12 * IBM Corporation - initial API and implementation 13 *******************************************************************************/ 14 package org.eclipse.jdt.internal.compiler.util; 15 16 /** 17 * HashSet of Object[] 18 */ 19 public final class HashSetOfInt implements Cloneable { 20 21 // to avoid using Enumerations, walk the individual tables skipping nulls 22 public int[] set; 23 24 public int elementSize; // number of elements in the table 25 int threshold; 26 HashSetOfInt()27 public HashSetOfInt() { 28 this(13); 29 } 30 HashSetOfInt(int size)31 public HashSetOfInt(int size) { 32 33 this.elementSize = 0; 34 this.threshold = size; // size represents the expected number of elements 35 int extraRoom = (int) (size * 1.75f); 36 if (this.threshold == extraRoom) 37 extraRoom++; 38 this.set = new int[extraRoom]; 39 } 40 41 @Override clone()42 public Object clone() throws CloneNotSupportedException { 43 HashSetOfInt result = (HashSetOfInt) super.clone(); 44 result.elementSize = this.elementSize; 45 result.threshold = this.threshold; 46 47 int length = this.set.length; 48 result.set = new int[length]; 49 System.arraycopy(this.set, 0, result.set, 0, length); 50 51 return result; 52 } 53 contains(int element)54 public boolean contains(int element) { 55 int length = this.set.length; 56 int index = element % length; 57 int currentElement; 58 while ((currentElement = this.set[index]) != 0) { 59 if (currentElement == element) 60 return true; 61 if (++index == length) { 62 index = 0; 63 } 64 } 65 return false; 66 } 67 add(int element)68 public int add(int element) { 69 int length = this.set.length; 70 int index = element % length; 71 int currentElement; 72 while ((currentElement = this.set[index]) != 0) { 73 if (currentElement == element) 74 return this.set[index] = element; 75 if (++index == length) { 76 index = 0; 77 } 78 } 79 this.set[index] = element; 80 81 // assumes the threshold is never equal to the size of the table 82 if (++this.elementSize > this.threshold) 83 rehash(); 84 return element; 85 } 86 remove(int element)87 public int remove(int element) { 88 int length = this.set.length; 89 int index = element % length; 90 int currentElement; 91 while ((currentElement = this.set[index]) != 0) { 92 if (currentElement == element) { 93 int existing = this.set[index]; 94 this.elementSize--; 95 this.set[index] = 0; 96 rehash(); 97 return existing; 98 } 99 if (++index == length) { 100 index = 0; 101 } 102 } 103 return 0; 104 } 105 rehash()106 private void rehash() { 107 108 HashSetOfInt newHashSet = new HashSetOfInt(this.elementSize * 2); // double the number of expected elements 109 int currentElement; 110 for (int i = this.set.length; --i >= 0;) 111 if ((currentElement = this.set[i]) != 0) 112 newHashSet.add(currentElement); 113 114 this.set = newHashSet.set; 115 this.threshold = newHashSet.threshold; 116 } 117 size()118 public int size() { 119 return this.elementSize; 120 } 121 122 @Override toString()123 public String toString() { 124 StringBuffer buffer = new StringBuffer(); 125 int element; 126 for (int i = 0, length = this.set.length; i < length; i++) 127 if ((element = this.set[i]) != 0) { 128 buffer.append(element); 129 if (i != length-1) 130 buffer.append('\n'); 131 } 132 return buffer.toString(); 133 } 134 } 135