src/java.base/share/classes/sun/security/util/ArrayUtil.java

/*
 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.security.util;

import java.util.List;
import java.util.function.BiFunction;
import java.security.*;
import jdk.internal.util.Preconditions;


/**
 * This class holds the various utility methods for array range checks.
 */

public final class ArrayUtil {

    private static final BiFunction<String, List<Integer>,
            ArrayIndexOutOfBoundsException> AIOOBE_SUPPLIER =
            Preconditions.outOfBoundsExceptionFormatter
            (ArrayIndexOutOfBoundsException::new);

    public static void blockSizeCheck(int len, int blockSize) {
        if ((len % blockSize) != 0) {
            throw new ProviderException("Internal error in input buffering");
        }
    }

    public static void nullAndBoundsCheck(byte[] array, int offset, int len) {
        // NPE is thrown when array is null
        Preconditions.checkFromIndexSize(offset, len, array.length, AIOOBE_SUPPLIER);
    }

    private static void swap(byte[] arr, int i, int j) {
        byte tmp = arr[i];
        arr[i] = arr[j];
        arr[j] = tmp;
    }

    public static void reverse(byte [] arr) {
        int i = 0;
        int j = arr.length - 1;

        while (i < j) {
            swap(arr, i, j);
            i++;
            j--;
        }
    }
}