1 /*
2  * Copyright (c) 2003, 2011, 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 {
usageError()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 
main(String[] args)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 }
77