/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * C# Flex 1.4                                                             *
 * Copyright (C) 2004-2005  Jonathan Gilbert <logic@deltaq.org>            *
 * Derived from:                                                           *
 *                                                                         *
 *   JFlex 1.4                                                             *
 *   Copyright (C) 1998-2004  Gerwin Klein <lsf@jflex.de>                  *
 *   All rights reserved.                                                  *
 *                                                                         *
 * This program is free software; you can redistribute it and/or modify    *
 * it under the terms of the GNU General Public License. See the file      *
 * COPYRIGHT for more information.                                         *
 *                                                                         *
 * This program 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 for more details.                            *
 *                                                                         *
 * You should have received a copy of the GNU General Public License along *
 * with this program; if not, write to the Free Software Foundation, Inc., *
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA                 *
 *                                                                         *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

using System;
using System.Text;

namespace CSFlex
{
    /**
     *
     * @author Gerwin Klein
     * @version JFlex 1.4, $Revision: 2.1 $, $Date: 2004/04/12 10:07:47 $
     * @author Jonathan Gilbert
     * @version CSFlex 1.4
     */
    public sealed class CharSet
    {
        internal const int BITS = 6; // the number of bits to shift (2^6 = 64)
        internal const int MOD = (1 << BITS) - 1; // modulus

        internal long[] bits;

        private int numElements;

        public CharSet()
        {
            bits = new long[1];
        }

        public CharSet(int initialSize, int character)
        {
            bits = new long[(initialSize >> BITS) + 1];
            add(character);
        }

        public void add(int character)
        {
            resize(character);

            if ((bits[character >> BITS] & (1L << (character & MOD))) == 0)
                numElements++;

            bits[character >> BITS] |= (1L << (character & MOD));
        }

        private int nbits2size(int nbits)
        {
            return ((nbits >> BITS) + 1);
        }

        private void resize(int nbits)
        {
            int needed = nbits2size(nbits);

            if (needed < bits.Length)
                return;

            long[] newbits = new long[Math.Max(bits.Length * 2, needed)];
            Array.Copy(bits, 0, newbits, 0, bits.Length);

            bits = newbits;
        }

        public bool isElement(int character)
        {
            int index = character >> BITS;
            if (index >= bits.Length)
                return false;
            return (bits[index] & (1L << (character & MOD))) != 0;
        }

        public CharSetEnumerator characters()
        {
            return new CharSetEnumerator(this);
        }

        public bool containsElements()
        {
            return numElements > 0;
        }

        public int size()
        {
            return numElements;
        }

        public override String ToString()
        {
            CharSetEnumerator @enum = characters();

            StringBuilder result = new StringBuilder("{");

            if (@enum.hasMoreElements())
                result.Append(@enum.nextElement());

            while (@enum.hasMoreElements())
            {
                int i = @enum.nextElement();
                result.Append(", ").Append(i);
            }

            result.Append("}");

            return result.ToString();
        }
    }
}
