package org.eclipse.jdt.internal.compiler.util; | |
/* | |
* (c) Copyright IBM Corp. 2000, 2001. | |
* All Rights Reserved. | |
*/ | |
import org.eclipse.jdt.internal.compiler.*; | |
/** | |
* Hashtable for non-zero int keys. | |
*/ | |
public final class HashtableOfInt { | |
// to avoid using Enumerations, walk the individual tables skipping nulls | |
public int[] keyTable; | |
public Object[] valueTable; | |
int elementSize; // number of elements in the table | |
int threshold; | |
public HashtableOfInt() { | |
this(13); | |
} | |
public HashtableOfInt(int size) { | |
this.elementSize = 0; | |
this.threshold = size; // size represents the expected number of elements | |
int extraRoom = (int) (size * 1.75f); | |
if (this.threshold == extraRoom) | |
extraRoom++; | |
this.keyTable = new int[extraRoom]; | |
this.valueTable = new Object[extraRoom]; | |
} | |
public boolean containsKey(int key) { | |
int index = key % valueTable.length; | |
int currentKey; | |
while ((currentKey = keyTable[index]) != 0) { | |
if (currentKey == key) | |
return true; | |
index = (index + 1) % keyTable.length; | |
} | |
return false; | |
} | |
public Object get(int key) { | |
int index = key % valueTable.length; | |
int currentKey; | |
while ((currentKey = keyTable[index]) != 0) { | |
if (currentKey == key) return valueTable[index]; | |
index = (index + 1) % keyTable.length; | |
} | |
return null; | |
} | |
public Object put(int key, Object value) { | |
int index = key % valueTable.length; | |
int currentKey; | |
while ((currentKey = keyTable[index]) != 0) { | |
if (currentKey == key) return valueTable[index] = value; | |
index = (index + 1) % keyTable.length; | |
} | |
keyTable[index] = key; | |
valueTable[index] = value; | |
// assumes the threshold is never equal to the size of the table | |
if (++elementSize > threshold) | |
rehash(); | |
return value; | |
} | |
private void rehash() { | |
HashtableOfInt newHashtable = new HashtableOfInt(elementSize * 2); // double the number of expected elements | |
int currentKey; | |
for (int i = keyTable.length; --i >= 0;) | |
if ((currentKey = keyTable[i]) != 0) | |
newHashtable.put(currentKey, valueTable[i]); | |
this.keyTable = newHashtable.keyTable; | |
this.valueTable = newHashtable.valueTable; | |
this.threshold = newHashtable.threshold; | |
} | |
public int size() { | |
return elementSize; | |
} | |
public String toString() { | |
String s = ""/*nonNLS*/; | |
Object object; | |
for (int i = 0, length = valueTable.length; i < length; i++) | |
if ((object = valueTable[i]) != null) | |
s += keyTable[i] + " -> "/*nonNLS*/ + object.toString() + "\n"/*nonNLS*/; | |
return s; | |
} | |
} |