Here you can find the source of computeCrc32(InputStream is)
static String computeCrc32(InputStream is) throws IOException
//package com.java2s; /*/*www. ja v a 2 s . c o m*/ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright 1997-2010 Oracle and/or its affiliates. All rights reserved. * * Oracle and Java are registered trademarks of Oracle and/or its affiliates. * Other names may be trademarks of their respective owners. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common * Development and Distribution License("CDDL") (collectively, the * "License"). You may not use this file except in compliance with the * License. You can obtain a copy of the License at * http://www.netbeans.org/cddl-gplv2.html * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the * specific language governing permissions and limitations under the * License. When distributing the software, include this License Header * Notice in each file and include the License file at * nbbuild/licenses/CDDL-GPL-2-CP. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the GPL Version 2 section of the License file that * accompanied this code. If applicable, add the following below the * License Header, with the fields enclosed by brackets [] replaced by * your own identifying information: * "Portions Copyrighted [year] [name of copyright owner]" * * Contributor(s): * * The Original Software is NetBeans. The Initial Developer of the Original * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun * Microsystems, Inc. All Rights Reserved. * * If you wish your version of this file to be governed by only the CDDL * or only the GPL Version 2, indicate your decision by adding * "[Contributor] elects to include this software in this distribution * under the [CDDL or GPL Version 2] license." If you do not indicate a * single choice of license, a recipient has the option to distribute * your version of this file under either the CDDL, the GPL Version 2 or * to extend the choice of license to its licensees as provided above. * However, if you add GPL Version 2 code and therefore, elected the GPL * Version 2 license, then the option applies only if the new code is * made subject to such option by the copyright holder. */ import java.io.IOException; import java.io.InputStream; import java.util.zip.CRC32; import java.util.zip.Checksum; public class Main { /** * Compute the CRC-32 of the contents of a stream. * \r\n and \r are both normalized to \n for purposes of the calculation. */ static String computeCrc32(InputStream is) throws IOException { Checksum crc = new CRC32(); int last = -1; int curr; while ((curr = is.read()) != -1) { if (curr != '\n' && last == '\r') { crc.update('\n'); } if (curr != '\r') { crc.update(curr); } last = curr; } if (last == '\r') { crc.update('\n'); } int val = (int) crc.getValue(); String hex = Integer.toHexString(val); while (hex.length() < 8) { hex = "0" + hex; // NOI18N } return hex; } }