/*
 * MIT License
 *
 * Copyright (c) 2018 emufog contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package emufog.graph;

import java.util.BitSet;

/**
 * The UniqueIDProvider keeps track of all IDs in use and calculates based
 * on that data the next available ID such that all IDs are unique.
 */
class UniqueIDProvider {

    /**
     * the current ID is the last one in use
     */
    private int current;

    /**
     * set to keep track of all used IDs
     */
    private final BitSet bitSet;

    /**
     * Creates a new ID provider.
     */
    UniqueIDProvider() {
        current = 0;
        bitSet = new BitSet();
    }

    /**
     * Calculates and returns the next available unique ID.
     * The ID is not marked as used.
     *
     * @return the new ID
     */
    int getNextID() {
        current = bitSet.nextClearBit(current);

        return current;
    }

    /**
     * Marks an ID as used so it cannot be assigned to another object.
     *
     * @param id the ID already in use
     */
    void markIDused(int id) {
        bitSet.set(id, true);
    }

    /**
     * Checks if the given ID is already in use.
     *
     * @param id ID to check
     * @return true if the ID already used, false otherwise
     */
    boolean isUsed(int id) {
        return bitSet.get(id);
    }
}

/*
 * MIT License
 *
 * Copyright (c) 2018 emufog contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package emufog.graph;

import java.util.BitSet;

/**
 * The UniqueIDProvider keeps track of all IDs in use and calculates based
 * on that data the next available ID such that all IDs are unique.
 */
class UniqueIDProvider {

    /**
     * the current ID is the last one in use
     */
    private int current;

    /**
     * set to keep track of all used IDs
     */
    private final BitSet bitSet;

    /**
     * Creates a new ID provider.
     */
    UniqueIDProvider() {
        current = 0;
        bitSet = new BitSet();
    }

    /**
     * Calculates and returns the next available unique ID.
     * The ID is not marked as used.
     *
     * @return the new ID
     */
    int getNextID() {
        current = bitSet.nextClearBit(current);
        markIDused(current);

        return current;
    }

    /**
     * Marks an ID as used so it cannot be assigned to another object.
     *
     * @param id the ID already in use
     */
    void markIDused(int id) {
        bitSet.set(id, true);
    }

    /**
     * Checks if the given ID is already in use.
     *
     * @param id ID to check
     * @return true if the ID already used, false otherwise
     */
    boolean isUsed(int id) {
        return bitSet.get(id);
    }
}

set the next id to true