/*
 * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 * THIS FILE WAS MODIFIED BY SUN MICROSYSTEMS, INC.
 */
package com.sun.xml.internal.fastinfoset.util;

import com.sun.xml.internal.org.jvnet.fastinfoset.FastInfosetException;
import com.sun.xml.internal.fastinfoset.CommonResourceBundle;


public class DuplicateAttributeVerifier {
    public static final int MAP_SIZE = 256;
    
    public int _currentIteration;
    
    public static class Entry {
        private int iteration;
        private int value;
        
        private Entry hashNext;
        
        private Entry poolNext;
    }
    
    private Entry[] _map;
       
    public final Entry _poolHead;
    public Entry _poolCurrent;
    private Entry _poolTail;
    
    
    public DuplicateAttributeVerifier() {
        _poolTail = _poolHead = new Entry();
    }
    
    public final void clear() {
        _currentIteration = 0;

        Entry e = _poolHead;
        while (e != null) {
            e.iteration = 0;
            e = e.poolNext;
        }
        
        reset();
    }
    
    public final void reset() {
        _poolCurrent = _poolHead;
        if (_map == null) {
            _map = new Entry[MAP_SIZE];
        }
    }
    
    private final void increasePool(int capacity) {
        if (_map == null) {
            _map = new Entry[MAP_SIZE];
            _poolCurrent = _poolHead;
        } else {
            final Entry tail = _poolTail;
            for (int i = 0; i < capacity; i++) {
                final Entry e = new Entry();
                _poolTail.poolNext = e;
                _poolTail = e;
            }

            _poolCurrent = tail.poolNext;
        }
    }
    
    public final void checkForDuplicateAttribute(int hash, int value) throws FastInfosetException {
        if (_poolCurrent == null) {
            increasePool(16);
        }
        
        // Get next free entry
        final Entry newEntry = _poolCurrent;
        _poolCurrent = _poolCurrent.poolNext;

        final Entry head = _map[hash];
        if (head == null || head.iteration < _currentIteration) {
            newEntry.hashNext = null;
            _map[hash] = newEntry;
            newEntry.iteration = _currentIteration;
            newEntry.value = value;
        } else {
            Entry e = head;
            do {
                if (e.value == value) {
                    reset();
                    throw new FastInfosetException(CommonResourceBundle.getInstance().getString("message.duplicateAttribute"));
                }
            } while ((e = e.hashNext) != null);
            
            newEntry.hashNext = head;
            _map[hash] = newEntry;
            newEntry.iteration = _currentIteration;
            newEntry.value = value;
        }        
    }
}