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
29import java.io.RandomAccessFile;
30import java.io.IOException;
31import java.util.Random;
32
33public 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}
77