net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/util/HashtableOfIntValues.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2004 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.compiler.util;
  12
  13 import net.sourceforge.phpdt.core.compiler.CharOperation;
  14
  15 /**
  16  * Hashtable of {char[] --> int}
  17  */
  18 public final class HashtableOfIntValues implements Cloneable {
  19
  20         public static final int NO_VALUE = Integer.MIN_VALUE;
  21
  22         // to avoid using Enumerations, walk the individual tables skipping nulls
  23         public char[] keyTable[];
  24
  25         public int valueTable[];
  26
  27         public int elementSize; // number of elements in the table
  28
  29         int threshold;
  30
  31         public HashtableOfIntValues() {
  32                 this(13);
  33         }
  34
  35         public HashtableOfIntValues(int size) {
  36
  37                 this.elementSize = 0;
  38                 this.threshold = size; // size represents the expected number of
  39                                                                 // elements
  40                 int extraRoom = (int) (size * 1.75f);
  41                 if (this.threshold == extraRoom)
  42                         extraRoom++;
  43                 this.keyTable = new char[extraRoom][];
  44                 this.valueTable = new int[extraRoom];
  45         }
  46
  47         public Object clone() throws CloneNotSupportedException {
  48                 HashtableOfIntValues result = (HashtableOfIntValues) super.clone();
  49                 result.elementSize = this.elementSize;
  50                 result.threshold = this.threshold;
  51
  52                 int length = this.keyTable.length;
  53                 result.keyTable = new char[length][];
  54                 System.arraycopy(this.keyTable, 0, result.keyTable, 0, length);
  55
  56                 length = this.valueTable.length;
  57                 result.valueTable = new int[length];
  58                 System.arraycopy(this.valueTable, 0, result.valueTable, 0, length);
  59                 return result;
  60         }
  61
  62         public boolean containsKey(char[] key) {
  63
  64                 int index = CharOperation.hashCode(key) % valueTable.length;
  65                 int keyLength = key.length;
  66                 char[] currentKey;
  67                 while ((currentKey = keyTable[index]) != null) {
  68                         if (currentKey.length == keyLength
  69                                         && CharOperation.equals(currentKey, key))
  70                                 return true;
  71                         index = (index + 1) % keyTable.length;
  72                 }
  73                 return false;
  74         }
  75
  76         public int get(char[] key) {
  77
  78                 int index = CharOperation.hashCode(key) % valueTable.length;
  79                 int keyLength = key.length;
  80                 char[] currentKey;
  81                 while ((currentKey = keyTable[index]) != null) {
  82                         if (currentKey.length == keyLength
  83                                         && CharOperation.equals(currentKey, key))
  84                                 return valueTable[index];
  85                         index = (index + 1) % keyTable.length;
  86                 }
  87                 return NO_VALUE;
  88         }
  89
  90         public int put(char[] key, int value) {
  91
  92                 int index = CharOperation.hashCode(key) % valueTable.length;
  93                 int keyLength = key.length;
  94                 char[] currentKey;
  95                 while ((currentKey = keyTable[index]) != null) {
  96                         if (currentKey.length == keyLength
  97                                         && CharOperation.equals(currentKey, key))
  98                                 return valueTable[index] = value;
  99                         index = (index + 1) % keyTable.length;
 100                 }
 101                 keyTable[index] = key;
 102                 valueTable[index] = value;
 103
 104                 // assumes the threshold is never equal to the size of the table
 105                 if (++elementSize > threshold)
 106                         rehash();
 107                 return value;
 108         }
 109
 110         public int removeKey(char[] key) {
 111
 112                 int index = CharOperation.hashCode(key) % valueTable.length;
 113                 int keyLength = key.length;
 114                 char[] currentKey;
 115                 while ((currentKey = keyTable[index]) != null) {
 116                         if (currentKey.length == keyLength
 117                                         && CharOperation.equals(currentKey, key)) {
 118                                 int value = valueTable[index];
 119                                 elementSize--;
 120                                 keyTable[index] = null;
 121                                 valueTable[index] = NO_VALUE;
 122                                 rehash();
 123                                 return value;
 124                         }
 125                         index = (index + 1) % keyTable.length;
 126                 }
 127                 return NO_VALUE;
 128         }
 129
 130         private void rehash() {
 131
 132                 HashtableOfIntValues newHashtable = new HashtableOfIntValues(
 133                                 elementSize * 2); // double the number of expected elements
 134                 char[] currentKey;
 135                 for (int i = keyTable.length; --i >= 0;)
 136                         if ((currentKey = keyTable[i]) != null)
 137                                 newHashtable.put(currentKey, valueTable[i]);
 138
 139                 this.keyTable = newHashtable.keyTable;
 140                 this.valueTable = newHashtable.valueTable;
 141                 this.threshold = newHashtable.threshold;
 142         }
 143
 144         public int size() {
 145                 return elementSize;
 146         }
 147
 148         public String toString() {
 149                 String s = ""; //$NON-NLS-1$
 150                 char[] key;
 151                 for (int i = 0, length = valueTable.length; i < length; i++)
 152                         if ((key = keyTable[i]) != null)
 153                                 s += new String(key) + " -> " + valueTable[i] + "\n"; //$NON-NLS-2$ //$NON-NLS-1$
 154                 return s;
 155         }
 156 }