/*
 * Copyright 2015 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
*/

package org.drools.core.util.bitmask;

public class AllSetBitMask extends SingleLongBitMask implements BitMask, AllSetMask {

    private static final AllSetBitMask INSTANCE = new AllSetBitMask();

    private AllSetBitMask() { }

    public static AllSetBitMask get() {
        return INSTANCE;
    }

    @Override
    public BitMask set(int index) {
        return this;
    }

    @Override
    public BitMask setAll(BitMask mask) {
        return this;
    }

    @Override
    public BitMask reset(int index) {
        return BitMask.getFull(index+1).reset(index);
    }

    @Override
    public BitMask resetAll(BitMask mask) {
        if (mask.isEmpty()) {
            return this;
        } else if (mask instanceof EmptyButLastBitMask) {
            return AllSetButLastBitMask.get();
        } else if (mask instanceof AllSetBitMask) {
            return EmptyBitMask.get();
        } else if (mask instanceof AllSetButLastBitMask) {
            return EmptyButLastBitMask.get();
        }
        return BitMask.getFull(mask instanceof LongBitMask ? 1 : 65).resetAll(mask);
    }

    @Override
    public boolean isSet(int index) {
        return true;
    }

    @Override
    public boolean isAllSet() {
        return true;
    }

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

    @Override
    public boolean intersects(BitMask mask) {
        return true;
    }

    @Override
    public long asLong() {
        return -1L;
    }

    @Override
    public AllSetBitMask clone() {
        return this;
    }

    @Override
    public String getInstancingStatement() {
        return AllSetBitMask.class.getCanonicalName() + ".get()";
    }
}
