de.tum.in.naturals.set.PowerNatBitSet Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of naturals-util Show documentation
Datastructures and utility classes for non-negative integers
The newest version!
/*
 * Copyright (C) 2017 Tobias Meggendorfer
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * 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, see .
 */

package de.tum.in.naturals.set;

import it.unimi.dsi.fastutil.Size64;
import it.unimi.dsi.fastutil.ints.IntCollection;
import java.util.AbstractSet;
import java.util.Iterator;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.annotation.Nullable;

class PowerNatBitSet extends AbstractSet implements Size64 {
    private final NatBitSet baseSet;
    private final int baseSize;

    PowerNatBitSet(NatBitSet baseSet) {
        assert !baseSet.isEmpty();
        this.baseSet = NatBitSets.compact(baseSet, true);
        baseSize = this.baseSet.size();
    }

    @Override
    public boolean isEmpty() {
        return false;
    }

    @Override
    public boolean contains(@Nullable Object obj) {
        return obj instanceof IntCollection && baseSet.containsAll((IntCollection) obj);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj instanceof PowerNatBitSet) {
            PowerNatBitSet other = (PowerNatBitSet) obj;
            return baseSet.equals(other.baseSet);
        }
        Logger.getLogger(PowerNatBitSet.class.getName()).log(Level.WARNING, "Calling equals on PowerNatBitSet");
        return super.equals(obj);
    }

    @Override
    public int hashCode() {
        Logger.getLogger(PowerNatBitSet.class.getName()).log(Level.WARNING, "Calling hashCode on PowerNatBitSet");
        return super.hashCode();
    }

    /**
     * Returns an iterator over the power set.
     * Warning: To avoid repeated allocation, the returned set is modified in-place!
     */
    @Override
    public Iterator iterator() {
        return new PowerNatBitSetIterator(baseSet);
    }

    @SuppressWarnings("deprecation")
    @Override
    public int size() {
        return baseSize >= Integer.SIZE ? Integer.MAX_VALUE : 1 << baseSize;
    }

    @Override
    public long size64() {
        return 1L << baseSize;
    }

    @Override
    public String toString() {
        return String.format("powerSet(%s)", baseSet);
    }
}