/*
* Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Resin Open Source is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
*
* Free SoftwareFoundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Scott Ferguson
*/
package com.caucho.util;
import java.util.Iterator;
/**
* The IntMap provides a simple hashmap from keys to integers. The API is
* an abbreviation of the HashMap collection API.
*
* <p>The convenience of IntMap is avoiding all the silly wrapping of
* integers.
*/
public class IdentityIntMap {
/**
* Encoding of a null entry. Since NULL is equal to Integer.MIN_VALUE,
* it's impossible to distinguish between the two.
*/
public final static int NULL = Integer.MIN_VALUE;
private static int DELETED = 0x1;
private Object []keys;
private int nullValue;
private int []values;
private byte []flags;
private int size;
private int mask;
/**
* Create a new IntMap. Default size is 16.
*/
public IdentityIntMap()
{
keys = new Object[16];
values = new int[16];
flags = new byte[16];
mask = keys.length - 1;
size = 0;
nullValue = NULL;
}
/**
* Clear the hashmap.
*/
public void clear()
{
nullValue = NULL;
for (int i = 0; i < values.length; i++) {
keys[i] = null;
flags[i] = 0;
values[i] = 0;
}
size = 0;
}
/**
* Returns the current number of entries in the map.
*/
public int size()
{
return size;
}
/**
* Puts a new value in the property table with the appropriate flags
*/
public int get(Object key)
{
if (key == null)
return nullValue;
int hash = System.identityHashCode(key) & mask;
while (true) {
Object mapKey = keys[hash];
if (mapKey == key)
return values[hash];
else if (mapKey == null) {
if ((flags[hash] & DELETED) == 0)
return NULL;
}
else if (mapKey.equals(key))
return values[hash];
hash = (hash + 1) & mask;
}
}
/**
* Expands the property table
*/
private void resize(int newSize)
{
Object []newKeys = new Object[newSize];
int []newValues = new int[newSize];
byte []newFlags = new byte[newSize];
mask = newKeys.length - 1;
for (int i = 0; i < keys.length; i++) {
if (keys[i] == null || (flags[i] & DELETED) != 0)
continue;
int hash = System.identityHashCode(keys[i]) & mask;
while (true) {
if (newKeys[hash] == null) {
newKeys[hash] = keys[i];
newValues[hash] = values[i];
newFlags[hash] = flags[i];
break;
}
hash = (hash + 1) & mask;
}
}
keys = newKeys;
values = newValues;
flags = newFlags;
}
/**
* Puts a new value in the property table with the appropriate flags
*/
public int put(Object key, int value)
{
if (key == null) {
int old = nullValue;
nullValue = value;
return old;
}
int hash = System.identityHashCode(key) & mask;
while (true) {
Object testKey = keys[hash];
if (testKey == null || (flags[hash] & DELETED) != 0) {
keys[hash] = key;
values[hash] = value;
flags[hash] = 0;
size++;
if (keys.length <= 2 * size)
resize(2 * keys.length);
return NULL;
}
else if (key != testKey && ! testKey.equals(key)) {
hash = (hash + 1) & mask;
continue;
}
else {
int old = values[hash];
values[hash] = value;
return old;
}
}
}
/**
* Deletes the entry. Returns true if successful.
*/
public int remove(Object key)
{
if (key == null) {
int old = nullValue;
nullValue = NULL;
return old;
}
int hash = System.identityHashCode(key) & mask;
while (true) {
Object mapKey = keys[hash];
if (mapKey == null)
return NULL;
else if (mapKey.equals(key)) {
flags[hash] |= DELETED;
size--;
keys[hash] = null;
return values[hash];
}
hash = (hash + 1) & mask;
}
}
/**
* Returns an iterator of the keys.
*/
public Iterator iterator()
{
return new IntMapIterator();
}
public String toString()
{
StringBuffer sbuf = new StringBuffer();
sbuf.append("IntMap[");
boolean isFirst = true;
for (int i = 0; i <= mask; i++) {
if ((flags[i] & DELETED) == 0 && keys[i] != null) {
if (! isFirst)
sbuf.append(", ");
isFirst = false;
sbuf.append(keys[i]);
sbuf.append(":");
sbuf.append(values[i]);
}
}
sbuf.append("]");
return sbuf.toString();
}
class IntMapIterator implements Iterator {
int index;
public boolean hasNext()
{
for (; index < keys.length; index++)
if (keys[index] != null && (flags[index] & DELETED) == 0)
return true;
return false;
}
public Object next()
{
for (; index < keys.length; index++)
if (keys[index] != null && (flags[index] & DELETED) == 0)
return keys[index++];
return null;
}
public void remove()
{
throw new RuntimeException();
}
}
}