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Java example source code file (AddJsum.java)
The AddJsum.java Java example source code/* * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package build.tools.addjsum; import java.io.*; import java.util.regex.*; /** Adds a checksum ("jsum") to the end of a text file. The algorithm used is known to the JVM and prevents trivial tampering with the class list used for class data sharing. */ public class AddJsum { private static final long JSUM_SEED = 0xCAFEBABEBABECAFEL; public static void main(String[] args) throws Exception { if (args.length != 2) { System.err.println("Usage: java AddJsum [input file name] [output file name]"); System.exit(1); } try { File inFile = new File(args[0]); File outFile = new File(args[1]); BufferedReader reader = new BufferedReader(new FileReader(inFile)); BufferedWriter writer = new BufferedWriter(new FileWriter(outFile)); Pattern p = Pattern.compile("# [0-9A-Fa-f]*"); long computedJsum = JSUM_SEED; String line = null; while ((line = reader.readLine()) != null) { if (line.length() > 0 && line.charAt(0) == '#') { Matcher m = p.matcher(line); if (!m.matches()) { writer.write(line); writer.newLine(); } } else { computedJsum = jsum(computedJsum, line); writer.write(line); writer.newLine(); } } String hex = Long.toHexString(computedJsum); int diff = 16 - hex.length(); for (int i = 0; i < diff; i++) { hex = "0" + hex; } writer.write("# " + hex); writer.newLine(); reader.close(); writer.close(); } catch (IOException e) { System.err.println("Error reading or writing file"); throw(e); } } private static long jsum(long start, String str) { long h = start; int len = str.length(); for (int i = 0; i < len; i++) { char c = str.charAt(i); if (c <= ' ') { /* Skip spaces and control characters */ continue; } h = 31 * h + c; } return h; } } Other Java examples (source code examples)Here is a short list of links related to this Java AddJsum.java source code file: |
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