Converts an int64 into a byte array with a maximum size of 8. - Java java.lang

Java examples for java.lang:byte Array Convert

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Description

Converts an int64 into a byte array with a maximum size of 8.

Demo Code

/**//w  w w  . jav  a 2s  . c  om
 * 
 * Copyright (C) 2004-2008 FhG Fokus
 *
 * This file is part of the FhG Fokus UPnP stack - an open source UPnP implementation
 * with some additional features
 *
 * You can redistribute the FhG Fokus UPnP stack and/or modify it
 * under the terms of the GNU General Public License Version 3 as published by
 * the Free Software Foundation.
 *
 * For a license to use the FhG Fokus UPnP stack software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact Fraunhofer FOKUS by e-mail at the following
 * addresses:
 *   upnpstack@fokus.fraunhofer.de
 *
 * The FhG Fokus UPnP stack 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>
 * or write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        long value = 2;
        int size = 2;
        System.out.println(java.util.Arrays.toString(int64ToByteArray(
                value, size)));
    }

    /**
     * Converts an int64 into a byte array with a maximum size of 8. Leading digits are filled with zero.
     */
    public static byte[] int64ToByteArray(long value, int size) {
        if (size > 8) {
            return null;
        }
        byte[] tempResult = new byte[8];
        clear(tempResult);

        int offset = 7;
        while (value != 0 && offset != -1) {
            tempResult[offset] = (byte) (value & 0xFF);
            value = value >> 8;
            offset--;
        }
        byte[] result = new byte[size];
        System.arraycopy(tempResult, 8 - size, result, 0, size);

        return result;
    }

    /** Fills a byte array with 0. */
    public static void clear(byte[] array) {
        fill(array, (byte) 0);
    }

    /** Fills a byte array with a value. */
    public static void fill(byte[] array, byte value) {
        if (array == null) {
            return;
        }
        for (int i = 0; i < array.length; i++) {
            array[i] = value;
        }
    }
}

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