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/*
 * Copyright (c) 2010, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.grizzly.utils;

import java.lang.reflect.Array;
import java.util.Arrays;

/**
 * Set of utility methods to work with Arrays.
 *
 * @author Alexey Stashok
 */
public final class ArrayUtils {
    // Reworked the java.util.Arrays's binarySearch
    public static int binarySearch(final int[] a, final int fromIndex, final int toIndex, final int key) {
        int low = fromIndex;
        int high = toIndex - 1;

        while (low <= high) {
            int mid = low + high >>> 1;
            int midVal = a[mid];

            if (midVal < key) {
                low = mid + 1;
            } else if (midVal > key) {
                high = mid - 1;
            } else {
                return mid; // key found
            }
        }
        return low; // key not found.
    }

    /**
     * Add unique element to the array.
     * 
     * @param  type of the array element
     * @param array array
     * @param element element to add
     *
     * @return array, which will contain the new element. Either new array instance, if passed array didn't contain the
     * element, or the same array instance, if the element is already present in the array.
     */
    public static  T[] addUnique(T[] array, T element) {
        return addUnique(array, element, true);
    }

    /**
     * Add unique element to the array.
     * 
     * @param  type of the array element
     * @param array array
     * @param element element to add
     * @param replaceElementIfEquals if passed element is equal to some element in the array then depending on this
     * parameter it will be replaced or not with the passed element.
     *
     * @return array, which will contain the new element. Either new array instance, if passed array didn't contain the
     * element, or the same array instance, if the element is already present in the array.
     */
    public static  T[] addUnique(final T[] array, final T element, final boolean replaceElementIfEquals) {

        final int idx = indexOf(array, element);
        if (idx == -1) {
            final int length = array.length;
            final T[] newArray = Arrays.copyOf(array, length + 1);
            newArray[length] = element;
            return newArray;
        }

        if (replaceElementIfEquals) {
            array[idx] = element;
        }

        return array;
    }

    /**
     * Removes the element from the array.
     * 
     * @param  type of the array element
     * @param array array
     * @param element the element to remove
     *
     * @return array, which won't contain the element. Either new array instance, if passed array contains the element, or
     * the same array instance, if the element wasn't present in the array. null will be returned if the last
     * element was removed from the passed array.
     */
    @SuppressWarnings("unchecked")
    public static  T[] remove(T[] array, Object element) {
        final int idx = indexOf(array, element);
        if (idx != -1) {
            final int length = array.length;

            if (length == 1) {
                return null;
            }

            final T[] newArray = (T[]) Array.newInstance(array.getClass().getComponentType(), length - 1);

            if (idx > 0) {
                System.arraycopy(array, 0, newArray, 0, idx);
            }

            if (idx < length - 1) {
                System.arraycopy(array, idx + 1, newArray, idx, length - idx - 1);
            }

            return newArray;
        }

        return array;
    }

    /**
     * Return the element index in the array.
     * 
     * @param  type of the array element
     * @param array array
     * @param element the element to look for.
     *
     * @return element's index, or -1 if element wasn't found.
     */
    public static  int indexOf(T[] array, Object element) {
        for (int i = 0; i < array.length; i++) {
            if (element.equals(array[i])) {
                return i;
            }
        }

        return -1;
    }
}