/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *      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.apache.commons.collections4;

/**

 * <p>

 * Operations on arrays, primitive arrays (like {@code int[]}) and primitive wrapper arrays (like {@code Integer[]}).

 * </p>

 * <p>

 * This class tries to handle {@code null} input gracefully. An exception will not be thrown for a {@code null} array

 * input. However, an Object array that contains a {@code null} element may throw an exception. Each method documents

 * its behaviour.

 * </p>

 * <p>

 * Package private, might move to an internal package if this needs to be public.

 * </p>

 * <p>

 * #ThreadSafe#

 * </p>

 *

 * @since 4.2 (Copied from Apache Commons Lang.)

 *

 */

class ArrayUtils {

    /**

     * The index value when an element is not found in a list or array: {@code -1}. This value is returned by methods in

     * this class and can also be used in comparisons with values returned by various method from

     * {@link java.util.List}.

     */

    static final int INDEX_NOT_FOUND = -1;

    /**

     * <p>

     * Checks if the object is in the given array.

     * </p>

     *

     * <p>

     * The method returns {@code false} if a {@code null} array is passed in.

     * </p>

     *

     * @param array

     *            the array to search through

     * @param objectToFind

     *            the object to find

     * @return {@code true} if the array contains the object

     */

    static boolean contains(final Object[] array, final Object objectToFind) {

        return indexOf(array, objectToFind) != INDEX_NOT_FOUND;

    }

    /**

     * <p>

     * Finds the index of the given object in the array.

     * </p>

     *

     * <p>

     * This method returns {@link #INDEX_NOT_FOUND} ({@code -1}) for a {@code null} input array.

     * </p>

     *

     * @param array

     *            the array to search through for the object, may be {@code null}

     * @param objectToFind

     *            the object to find, may be {@code null}

     * @return the index of the object within the array, {@link #INDEX_NOT_FOUND} ({@code -1}) if not found or

     *         {@code null} array input

     */

    static <T> int indexOf(final T[] array, final Object objectToFind) {

        return indexOf(array, objectToFind, 0);

    }

    /**

     * <p>

     * Finds the index of the given object in the array starting at the given index.

     * </p>

     *

     * <p>

     * This method returns {@link #INDEX_NOT_FOUND} ({@code -1}) for a {@code null} input array.

     * </p>

     *

     * <p>

     * A negative startIndex is treated as zero. A startIndex larger than the array length will return

     * {@link #INDEX_NOT_FOUND} ({@code -1}).

     * </p>

     *

     * @param array

     *            the array to search through for the object, may be {@code null}

     * @param objectToFind

     *            the object to find, may be {@code null}

     * @param startIndex

     *            the index to start searching at

     * @return the index of the object within the array starting at the index, {@link #INDEX_NOT_FOUND} ({@code -1}) if

     *         not found or {@code null} array input

     */

    static int indexOf(final Object[] array, final Object objectToFind, int startIndex) {

        if (array == null) {

            return INDEX_NOT_FOUND;

        }

        if (startIndex < 0) {

            startIndex = 0;

        }

        if (objectToFind == null) {

            for (int i = startIndex; i < array.length; i++) {

                if (array[i] == null) {

                    return i;

                }

            }

        } else {

            for (int i = startIndex; i < array.length; i++) {

                if (objectToFind.equals(array[i])) {

                    return i;

                }

            }

        }

        return INDEX_NOT_FOUND;

    }

}