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package com.couchbase.lite.util;

/**
 * Useful ArrayUtils taken from android security package.
 * Source: https://github.com/android/platform_frameworks_base/blob/master/keystore/java/android/security/ArrayUtils.java
 * Created by pasin on 8/28/15.
 */
public abstract class ArrayUtils {
    private ArrayUtils() {}

    public static String[] nullToEmpty(String[] array) {
        return (array != null) ? array : new String[0];
    }

    public static String[] cloneIfNotEmpty(String[] array) {
        return ((array != null) && (array.length > 0)) ? array.clone() : array;
    }

    public static byte[] concat(byte[] arr1, byte[] arr2) {
        return concat(arr1, 0, (arr1 != null) ? arr1.length : 0,
                arr2, 0, (arr2 != null) ? arr2.length : 0);
    }

    public static byte[] concat(byte[] arr1, int offset1, int len1,
                                byte[] arr2, int offset2, int len2) {
        if (len1 == 0) {
            return subarray(arr2, offset2, len2);
        } else if (len2 == 0) {
            return subarray(arr1, offset1, len1);
        } else {
            byte[] result = new byte[len1 + len2];
            System.arraycopy(arr1, offset1, result, 0, len1);
            System.arraycopy(arr2, offset2, result, len1, len2);
            return result;
        }
    }

    public static byte[] subarray(byte[] arr, int offset, int len) {
        if (len == 0) {
            return new byte[0];
        }
        if ((offset == 0) && (len == arr.length)) {
            return arr;
        }
        byte[] result = new byte[len];
        System.arraycopy(arr, offset, result, 0, len);
        return result;
    }
}