/*

 * 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.

 *

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 */

/* @test

   @bug 4027717

   @summary Check for correct implementation of RandomAccessFile.skipBytes

   */

import java.io.*;

public class SkipBytes{

    /*

     * doTest attempts to skip num_to_skip bytes in raf starting from position 0.

     * It also does a read after the skip to check if EOF has been reached

     * correctly or incorrectly.

     */

    private static void doTest(RandomAccessFile raf, int start, int num_to_skip)

        throws Exception

    {

        raf.seek(start);

        long cur_ptr = raf.getFilePointer();

        int length = (int) raf.length();

        System.err.println("\nCurrent pointer = " + cur_ptr + " length = " +

                           length + " num_to_skip = " + num_to_skip);

        //Do the Skip test

        int num_skipped = raf.skipBytes(num_to_skip);

        System.err.println("After skipBytes -- no. skipped = " + num_skipped);

        // if num_to_skip is negative do the negative skip test

        if (num_to_skip <= 0) {

            if (num_skipped != 0){

                System.err.println("Negative Skip Test Failed");

                throw new RuntimeException("Negative Skip Test Failed");

            }

            else {

                System.err.println("Negative Skip Test Succeeded");

            }

        }

        cur_ptr = raf.getFilePointer();

        System.err.println("Current pointer = " + cur_ptr);

        // Check if skip has gone beyond EOF.

        if (cur_ptr > length) {

            System.err.println("Past EOF Skip Test Failed");

            throw new RuntimeException("Past EOF Skip Test Failed");

        }

        else {

            System.err.println("Past EOF Skip Test Succeeded");

        }

        // do read test

        int byte_read = raf.read();

        if ( (cur_ptr == length) &&

             (byte_read != -1) ) {

            System.err.println("byte_read = " + byte_read +

                               " Read Test Failed ......");

            throw new RuntimeException("Read Test Failed");

        }

        else {

            System.err.println("byte_read = " + byte_read +

                               " Read Test Succeeded");

        }

    }

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

        RandomAccessFile raf = new RandomAccessFile("input.txt" , "rw");

        try {

            int length = (int)raf.length();

            doTest(raf , 0 , 2*length);

            doTest(raf , 0 , length);

            doTest(raf , 0 , length/2);

            doTest(raf , length/2 , -2);

            doTest(raf , length , 0);

            doTest(raf , 0 , -1);

        } finally{

            raf.close();

        }

    }

}