/*

 * 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.

 *

 * 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.

 *

 */

/* @test

   @summary General tests of the setLength method -- Should migrate to 1.2 JCK

 */

import java.io.*;

public class SetLength {

    static void fail(String s) {

        throw new RuntimeException(s);

    }

    static void go(File fn, int max) throws IOException {

        int chunk = max / 4;

        long i;

        RandomAccessFile f;

        f = new RandomAccessFile(fn, "rw");

        f.setLength(2 * chunk);

        if (f.length() != 2 * chunk) fail("Length not increased to " + (2 * chunk));

        if ((i = f.getFilePointer()) != 0) fail("File pointer shifted to " + i);

        byte[] buf = new byte[max];

        f.write(buf);

        if (f.length() != max) fail("Write didn't work");

        if (f.getFilePointer() != max) fail("File pointer inconsistent");

        f.setLength(3 * chunk);

        if (f.length() != 3 * chunk) fail("Length not reduced to " + 3 * chunk);

        if (f.getFilePointer() != 3 * chunk) fail("File pointer not shifted to " + (3 * chunk));

        f.seek(1 * chunk);

        if (f.getFilePointer() != 1 * chunk) fail("File pointer not shifted to " + (1 * chunk));

        f.setLength(2 * chunk);

        if (f.length() != 2 * chunk) fail("Length not reduced to " + (2 * chunk));

        if (f.getFilePointer() != 1 * chunk) fail("File pointer not shifted to " + (1 * chunk));

        f.close();

    }

    public static void main(String[] args) throws IOException {

        File fn = new File("x.SetLength");

        try {

            go(fn, 20);

            fn.delete();

            go(fn, 64 * 1024);

            RandomAccessFile f = new RandomAccessFile(fn, "r");

            boolean thrown = false;

            try {

                f.setLength(3);

            } catch (IOException x) {

                thrown = true;

            }

            if (!thrown) fail("setLength succeeded on a file opened read-only");

            f.close();

        }

        finally {

            fn.delete();

        }

    }

}