| /******************************************************************************* |
| * Copyright (c) 2006, 2009 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jdt.internal.compiler.util; |
| |
| import org.eclipse.jdt.core.compiler.CharOperation; |
| |
| /** |
| * A simple lookup table is a non-synchronized Hashtable, whose keys |
| * and values are char[]. It also uses linear probing to resolve collisions |
| * rather than a linked list of hash table entries. |
| */ |
| public final class SimpleSetOfCharArray implements Cloneable { |
| |
| // to avoid using Enumerations, walk the individual values skipping nulls |
| public char[][] values; |
| public int elementSize; // number of elements in the table |
| public int threshold; |
| |
| public SimpleSetOfCharArray() { |
| this(13); |
| } |
| |
| public SimpleSetOfCharArray(int size) { |
| if (size < 3) size = 3; |
| this.elementSize = 0; |
| this.threshold = size + 1; // size is the expected number of elements |
| this.values = new char[2 * size + 1][]; |
| } |
| |
| public Object add(char[] object) { |
| int length = this.values.length; |
| int index = (CharOperation.hashCode(object) & 0x7FFFFFFF) % length; |
| char[] current; |
| while ((current = this.values[index]) != null) { |
| if (CharOperation.equals(current, object)) return this.values[index] = object; |
| if (++index == length) index = 0; |
| } |
| this.values[index] = object; |
| |
| // assumes the threshold is never equal to the size of the table |
| if (++this.elementSize > this.threshold) rehash(); |
| return object; |
| } |
| |
| public void asArray(Object[] copy) { |
| if (this.elementSize != copy.length) |
| throw new IllegalArgumentException(); |
| int index = this.elementSize; |
| for (int i = 0, l = this.values.length; i < l && index > 0; i++) |
| if (this.values[i] != null) |
| copy[--index] = this.values[i]; |
| } |
| |
| public void clear() { |
| for (int i = this.values.length; --i >= 0;) |
| this.values[i] = null; |
| this.elementSize = 0; |
| } |
| |
| public Object clone() throws CloneNotSupportedException { |
| SimpleSetOfCharArray result = (SimpleSetOfCharArray) super.clone(); |
| result.elementSize = this.elementSize; |
| result.threshold = this.threshold; |
| |
| int length = this.values.length; |
| result.values = new char[length][]; |
| System.arraycopy(this.values, 0, result.values, 0, length); |
| return result; |
| } |
| |
| public char[] get(char[] object) { |
| int length = this.values.length; |
| int index = (CharOperation.hashCode(object) & 0x7FFFFFFF) % length; |
| char[] current; |
| while ((current = this.values[index]) != null) { |
| if (CharOperation.equals(current, object)) return current; |
| if (++index == length) index = 0; |
| } |
| this.values[index] = object; |
| |
| // assumes the threshold is never equal to the size of the table |
| if (++this.elementSize > this.threshold) rehash(); |
| return object; |
| } |
| |
| public boolean includes(char[] object) { |
| int length = this.values.length; |
| int index = (CharOperation.hashCode(object) & 0x7FFFFFFF) % length; |
| char[] current; |
| while ((current = this.values[index]) != null) { |
| if (CharOperation.equals(current, object)) return true; |
| if (++index == length) index = 0; |
| } |
| return false; |
| } |
| |
| public char[] remove(char[] object) { |
| int length = this.values.length; |
| int index = (CharOperation.hashCode(object) & 0x7FFFFFFF) % length; |
| char[] current; |
| while ((current = this.values[index]) != null) { |
| if (CharOperation.equals(current, object)) { |
| this.elementSize--; |
| char[] oldValue = this.values[index]; |
| this.values[index] = null; |
| if (this.values[index + 1 == length ? 0 : index + 1] != null) |
| rehash(); // only needed if a possible collision existed |
| return oldValue; |
| } |
| if (++index == length) index = 0; |
| } |
| return null; |
| } |
| |
| private void rehash() { |
| SimpleSetOfCharArray newSet = new SimpleSetOfCharArray(this.elementSize * 2); // double the number of expected elements |
| char[] current; |
| for (int i = this.values.length; --i >= 0;) |
| if ((current = this.values[i]) != null) |
| newSet.add(current); |
| |
| this.values = newSet.values; |
| this.elementSize = newSet.elementSize; |
| this.threshold = newSet.threshold; |
| } |
| |
| public String toString() { |
| String s = ""; //$NON-NLS-1$ |
| char[] object; |
| for (int i = 0, l = this.values.length; i < l; i++) |
| if ((object = this.values[i]) != null) |
| s += new String(object) + "\n"; //$NON-NLS-1$ |
| return s; |
| } |
| } |