SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package net.multiphasicapps.collections;

import cc.squirreljme.runtime.cldc.debug.Debugging;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Iterator;

/**
 * This is a set which allows enumeration values to be stored in it efficiently
 * using only a bit field.
 *
 * @since 2018/03/21
 */
public final class EnumSet<T extends Enum<T>>
    extends AbstractSet<T>
{
    /** The type of class being stored. */
    protected final Class<T> type;
    
    /** The number of used bits so far. */
    protected final int numbits;
    
    /** The number of ints in use. */
    protected final int numints;
    
    /** The values which are in the set, split into fields. */
    private int[] _bits;
    
    /** Is the null element in this set? */
    private boolean _hasnull;
    
    /**
     * Initializes an empty enumeration set.
     *
     * @param __cl The class type to store.
     * @throws NullPointerException On null arguments.
     * @since 2018/03/21
     */
    public EnumSet(Class<T> __cl)
        throws NullPointerException
    {
        this(__cl, EmptySet.<T>empty());
    }
    
    /**
     * Initializes an enumeration set with the given initial values.
     *
     * @param __cl The class type to store.
     * @param __v The initial values to store.
     * @throws NullPointerException On null arguments.
     * @since 2018/03/21
     */
    public EnumSet(Class<T> __cl, Collection<? extends T> __v)
        throws NullPointerException
    {
        if (__cl == null || __v == null)
            throw new NullPointerException("NARG");
        
        this.type = __cl;
        
        // Setup storage bits
        this.numbits = 0;
        this.numints = 0;
        this._bits = new int[0];
        
        // Add values
        for (T v : __v)
            this.add(v);
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/03/21
     */
    @Override
    public final boolean add(T __v)
    {
        // Adding null element?
        if (__v == null)
        {
            boolean hasnull = this._hasnull;
            if (hasnull)
                return false;
            else
            {
                this._hasnull = true;
                return true;
            }
        }
        
        // Need a place to store
        if (true)
            throw Debugging.todo();
        
        // Determine bit position
        int bit = __v.ordinal(),
            high = bit >>> 5;
        bit &= 0x1F;
        int flag = (1 << bit);
        
        // Did it have it before?
        int[] bits = this._bits;
        boolean had = ((bits[high] & flag) != 0);
        
        // Set it
        bits[high] |= flag;
        
        // The collection only changes if it did not have the bit
        return !had;
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/03/21
     */
    @Override
    public final boolean contains(Object __o)
    {
        // Only has null if it was explicitely added
        if (__o == null)
            return this._hasnull;
        
        if (!this.type.isInstance(__o))
            return false;
        
        // Determine bit position
        int bit = ((Enum)__o).ordinal(),
            high = bit >>> 5;
        bit &= 0x1F;
        
        return 0 != (this._bits[high] & (1 << bit));
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/03/21
     */
    @Override
    public final Iterator<T> iterator()
    {
        throw Debugging.todo();
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/03/21
     */
    @Override
    public final boolean remove(Object __v)
    {
        throw Debugging.todo();
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/03/21
     */
    @Override
    public final int size()
    {
        throw Debugging.todo();
    }
}