Return a long value from bytearray "ar" starting at the offset "offset". - Java java.lang

Java examples for java.lang:byte array to long

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Description

Return a long value from bytearray "ar" starting at the offset "offset".

Demo Code

/*//from  w ww .  ja  va  2 s  .  c  om
 * DomUI Java User Interface - shared code
 * Copyright (c) 2010 by Frits Jalvingh, Itris B.V.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * See the "sponsors" file for a list of supporters.
 *
 * The latest version of DomUI and related code, support and documentation
 * can be found at http://www.domui.org/
 * The contact for the project is Frits Jalvingh <jal@etc.to>.
 */
import java.sql.*;
import java.util.*;

public class Main{
    public static void main(String[] argv) throws Exception{
        byte[] ba = new byte[]{34,35,36,37,37,37,67,68,69};
        int offset = 2;
        System.out.println(getLong(ba,offset));
    }
    /**
     * Return a long value from bytearray "ar" starting at the offset "offset".
     *
     * @param ar
     * @param offset
     * @param length
     * @return
     */
    public static long getLong(byte[] ba, int offset) {
        long a = ByteArrayUtil.getInt(ba, offset + 4); // Get the 4 most significant bytes (int).
        long b = ByteArrayUtil.getInt(ba, offset); // Get the 4 less significant byted (int).
        a = a << 32; // Make them the 4 most significant bytes.
        b = b & 0x00000000ffffffffl; // Make sure the sign is removed (possible sign for the 4 most significant bytes).
        b |= a; // Merge the two values

        return b; // Return the original long.
    }
    /**
     *   Returns an integer packed into a byte array.
     */
    public static int getInt(byte[] ba, int offset) {
        int val = (ba[offset + 3] & 0xff);

        val |= (ba[offset] & 0xff) << 24;
        val |= (ba[offset + 1] & 0xff) << 16;
        val |= (ba[offset + 2] & 0xff) << 8;
        return val;
    }
}

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