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JDBC Driver for the Firebird RDBMS
There is a newer version: 6.0.0-beta-1
/*
 * Firebird Open Source JDBC Driver
 *
 * Distributable under LGPL license.
 * You may obtain a copy of the License at http://www.gnu.org/copyleft/lgpl.html
 *
 * This program 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
 * LGPL License for more details.
 *
 * This file was created by members of the firebird development team.
 * All individual contributions remain the Copyright (C) of those
 * individuals.  Contributors to this file are either listed here or
 * can be obtained from a source control history command.
 *
 * All rights reserved.
 */
package org.firebirdsql.util;

import java.util.Base64;

/**
 * Helper methods for byte arrays.
 *
 * @author Mark Rotteveel
 * @since 3.0
 */
@InternalApi
public final class ByteArrayHelper {

    //@formatter:off
    private static final char[] BYTE_2_HEX=(
            "000102030405060708090A0B0C0D0E0F"+
            "101112131415161718191A1B1C1D1E1F"+
            "202122232425262728292A2B2C2D2E2F"+
            "303132333435363738393A3B3C3D3E3F"+
            "404142434445464748494A4B4C4D4E4F"+
            "505152535455565758595A5B5C5D5E5F"+
            "606162636465666768696A6B6C6D6E6F"+
            "707172737475767778797A7B7C7D7E7F"+
            "808182838485868788898A8B8C8D8E8F"+
            "909192939495969798999A9B9C9D9E9F"+
            "A0A1A2A3A4A5A6A7A8A9AAABACADAEAF"+
            "B0B1B2B3B4B5B6B7B8B9BABBBCBDBEBF"+
            "C0C1C2C3C4C5C6C7C8C9CACBCCCDCECF"+
            "D0D1D2D3D4D5D6D7D8D9DADBDCDDDEDF"+
            "E0E1E2E3E4E5E6E7E8E9EAEBECEDEEEF"+
            "F0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF").toCharArray();
    //@formatter:on

    private ByteArrayHelper() {
        // no instances
    }

    /**
     * Converts the provided byte array to a hexadecimal string
     * 
     * Adapted from https://stackoverflow.com/a/21429909/466862
     * by higginse
     * 
     *
     * @param bytes
     *         byte array (not {@code null}
     * @return String with the content of the byte array in hexadecimal.
     */
    public static String toHexString(byte[] bytes) {
        final int length = bytes.length;
        final char[] chars = new char[length << 1];
        final char[] byte2Hex = BYTE_2_HEX;
        int index = 0;
        int offset = 0;
        while (offset < length) {
            int hexIndex = (bytes[offset++] & 0xFF) << 1;
            chars[index++] = byte2Hex[hexIndex++];
            chars[index++] = byte2Hex[hexIndex];
        }
        return new String(chars);
    }

    /**
     * Converts the provided hexadecimal string to a byte array.
     *
     * @param hexString
     *         Hexadecimal string
     * @return byte array
     * @since 4.0
     */
    public static byte[] fromHexString(String hexString) {
        final int length = hexString.length() / 2;
        final byte[] bytes = new byte[length];
        for (int byteIdx = 0; byteIdx < length; byteIdx++) {
            bytes[byteIdx] = (byte) ((Character.digit(hexString.charAt(2 * byteIdx), 16) << 4)
                    + Character.digit(hexString.charAt(2 * byteIdx + 1), 16));
        }
        return bytes;
    }

    /**
     * Decodes a base64 encoded string to a byte array.
     *
     * @param base64
     *         Base64 encoded data
     * @return byte array after decoding
     */
    public static byte[] fromBase64String(String base64) {
        return Base64.getDecoder().decode(base64);
    }

    /**
     * Decodes a base64url encoded string to a byte array.
     * 
     * Base64url applies the "URL and Filename safe" Base 64 Alphabet.
     * 
     *
     * @param base64url
     *         Base64url encoded data
     * @return byte array after decoding
     * @since 5
     */
    public static byte[] fromBase64urlString(String base64url) {
        return Base64.getUrlDecoder().decode(base64url);
    }

    /**
     * Returns the index of the first occurrence of {@code b} in {@code array}.
     *
     * @param array
     *         Array to search
     * @param b
     *         byte to find
     * @return the index of the first occurrence of {@code b}, or {@code -1} if {@code b} is not in the array
     * @since 5
     */
    public static int indexOf(byte[] array, byte b) {
        for (int idx = 0; idx < array.length; idx++) {
            if (array[idx] == b) return idx;
        }
        return -1;
    }

}