1 /*

     2  * Copyright 1997 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  */

    23 

    24 

    25 /* @test

    26    @bug 4027717

    27    @summary Check for correct implementation of RandomAccessFile.skipBytes

    28    */

    29 

    30 

    31 import java.io.*;

    32 

    33 public class SkipBytes{

    34 

    35 

    36     /*

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

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

    39      * correctly or incorrectly.

    40      */

    41 

    42 

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

    44         throws Exception

    45     {

    46 

    47         raf.seek(start);

    48 

    49         long cur_ptr = raf.getFilePointer();

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

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

    52                            length + " num_to_skip = " + num_to_skip);

    53 

    54         //Do the Skip test

    55         int num_skipped = raf.skipBytes(num_to_skip);

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

    57 

    58         // if num_to_skip is negative do the negative skip test

    59         if (num_to_skip <= 0) {

    60             if (num_skipped != 0){

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

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

    63             }

    64             else {

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

    66             }

    67         }

    68 

    69         cur_ptr = raf.getFilePointer();

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

    71 

    72         // Check if skip has gone beyond EOF.

    73         if (cur_ptr > length) {

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

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

    76         }

    77         else {

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

    79         }

    80 

    81         // do read test

    82         int byte_read = raf.read();

    83         if ( (cur_ptr == length) &&

    84              (byte_read != -1) ) {

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

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

    87             throw new RuntimeException("Read Test Failed");

    88         }

    89         else {

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

    91                                " Read Test Succeeded");

    92         }

    93 

    94     }

    95 

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

    97 

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

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

   100 

   101         doTest(raf , 0 , 2*length);

   102         doTest(raf , 0 , length);

   103         doTest(raf , 0 , length/2);

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

   105         doTest(raf , length , 0);

   106         doTest(raf , 0 , -1);

   107 

   108     }

   109 

   110 }