1 /*
   2  * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /*
  25  *
  26  * Driven by: 3GBZipFiles.sh
  27  */
  28 
  29 import java.io.RandomAccessFile;
  30 import java.io.IOException;
  31 import java.util.Random;
  32 
  33 public class FileBuilder {
  34     private static void usageError() {
  35         System.err.println("Usage: FileBuilder filetype filename filesize");
  36         System.err.println("");
  37         System.err.println("Makes a file named FILENAME of size FILESIZE.");
  38         System.err.println("If FILETYPE is \"MostlyEmpty\", the file contents is mostly null bytes");
  39         System.err.println("(which might occupy no disk space if the right OS support exists).");
  40         System.err.println("If FILETYPE is \"SlightlyCompressible\", the file contents are");
  41         System.err.println("approximately 90% random data.");
  42         System.exit(1);
  43     }
  44 
  45     public static void main (String[] args) throws IOException {
  46         if (args.length != 3)
  47             usageError();
  48         String filetype = args[0];
  49         String filename = args[1];
  50         long   filesize = Long.parseLong(args[2]);
  51 
  52         if (! (filetype.equals("MostlyEmpty") ||
  53                filetype.equals("SlightlyCompressible")))
  54             usageError();
  55 
  56         try (RandomAccessFile raf = new RandomAccessFile(filename, "rw")) {
  57             if (filetype.equals("SlightlyCompressible")) {
  58                 byte[] randomBytes = new byte[16384];
  59                 byte[] nullBytes   = new byte[randomBytes.length/10];
  60                 Random rand = new Random();
  61                 for (int i = 0; raf.length() < filesize; ++i) {
  62                     rand.nextBytes(randomBytes);
  63                     raf.write(nullBytes);
  64                     raf.write(randomBytes);
  65                 }
  66             }
  67 
  68             // Make sure file is exactly the requested size, and that
  69             // a unique identifying trailer is written.
  70             byte[] filenameBytes = filename.getBytes("UTF8");
  71             raf.seek(filesize-filenameBytes.length);
  72             raf.write(filenameBytes);
  73             raf.setLength(filesize);
  74         }
  75     }
  76 }