Here you can find the source of bytesToLong(byte[] bytes, int off, boolean bigEndian)
public static long bytesToLong(byte[] bytes, int off, boolean bigEndian)
//package com.java2s; /* ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1/*from w ww. j a v a 2 s. com*/ * * The contents of this file are subject to the Mozilla Public License Version * 1.1 (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the * License. * * The Original Code is part of dcm4che, an implementation of DICOM(TM) in * Java(TM), hosted at https://github.com/gunterze/dcm4che. * * The Initial Developer of the Original Code is * Agfa Healthcare. * Portions created by the Initial Developer are Copyright (C) 2011 * the Initial Developer. All Rights Reserved. * * Contributor(s): * See @authors listed below * * Alternatively, the contents of this file may be used under the terms of * either the GNU General Public License Version 2 or later (the "GPL"), or * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */ public class Main { public static long bytesToLong(byte[] bytes, int off, boolean bigEndian) { return bigEndian ? bytesToLongBE(bytes, off) : bytesToLongLE(bytes, off); } public static long bytesToLongBE(byte[] bytes, int off) { return ((long) bytes[off] << 56) + ((long) (bytes[off + 1] & 255) << 48) + ((long) (bytes[off + 2] & 255) << 40) + ((long) (bytes[off + 3] & 255) << 32) + ((long) (bytes[off + 4] & 255) << 24) + ((bytes[off + 5] & 255) << 16) + ((bytes[off + 6] & 255) << 8) + (bytes[off + 7] & 255); } public static long bytesToLongLE(byte[] bytes, int off) { return ((long) bytes[off + 7] << 56) + ((long) (bytes[off + 6] & 255) << 48) + ((long) (bytes[off + 5] & 255) << 40) + ((long) (bytes[off + 4] & 255) << 32) + ((long) (bytes[off + 3] & 255) << 24) + ((bytes[off + 2] & 255) << 16) + ((bytes[off + 1] & 255) << 8) + (bytes[off] & 255); } }